$ 1,033

$ 1,030

12,604

12,155

2,379

2,246

404

430

16,420

15,861

942

985

10,465

10,519

3,318

3,882

773

764

467

447

15,965

16,597

32,385

32,458

12,604

12,155

Short-term debt and current portion of long-term debt

1,647

1,711

186

864

804

15,301

14,755

4,389

4,450

1,170

1,259

559

615

540

558

429

544

7,087

7,426

COMMITMENTS AND CONTINGENCIES

22,388

22,181

Additional paid-in capital

EQUITY

^[1]

10,615

10,538

Accumulated other comprehensive loss, net of tax

^[1]

1,201

1,104

^[1]

(1,961)

(1,513)

Treasury shares, at cost, 17,519 in 2018 and 2017 and 40,000 shares, €1 nominal value, in 2018 and 2017

^[1]

(3)

^[1]

9,852

10,126

^[1]

119

123

^[1]

9,971

10,249

CASH FLOWS FROM OPERATING ACTIVITIES

^[1]

$ 32,385

$ 32,458

[1]

Equity includes (a) Ordinary shares $0.000304635 nominal value; Authorized 1,510,003,775; Issued 128,921,530 (2018) and 132,139,581 (2017); Outstanding 128,921,530 (2018) and 132,139,581 (2017); (b) Ordinary shares, €1 nominal value; Authorized and Issued 40,000 shares in 2018 and 2017; and (c) Preference shares, $0.000115 nominal value; Authorized 1,000,000,000 and Issued none in 2018 and 2017.

Consolidated Balance Sheets (Parenthetical)	Dec. 31, 2018 $ / shares shares	Dec. 31, 2018 € / shares shares	Dec. 31, 2017 $ / shares shares	Dec. 31, 2017 € / shares shares
Preference shares, nominal value (USD per share) \| $ / shares	$ 0.000115		$ 0.000115
Preference shares, shares authorized	1,000,000,000	1,000,000,000	1,000,000,000	1,000,000,000
Preference shares, shares issued	0	0	0	0
Ordinary shares, $0.000304635 nominal value [Member]
Ordinary shares, nominal value (euro per share) \| $ / shares	$ 0.000304635		$ 0.000304635
Ordinary shares, shares authorized	1,510,003,775	1,510,003,775	1,510,003,775	1,510,003,775
Ordinary shares, shares issued	128,921,530	128,921,530	132,139,581	132,139,581
Ordinary shares, shares outstanding	128,921,530	128,921,530	132,139,581	132,139,581
Treasury shares	17,519	17,519	17,519	17,519
Ordinary shares, €1 nominal value [Member]
Ordinary shares, nominal value (euro per share) \| € / shares		€ 1		€ 1
Ordinary shares, shares authorized	40,000	40,000	40,000	40,000
Ordinary shares, shares issued	40,000	40,000	40,000	40,000
Treasury shares	40,000	40,000	40,000	40,000

Consolidated Statements of Cash Flows - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Adjustments to reconcile net income to total net cash from operating activities:

$ 715

$ 592

$ 438

213

^[1]

252

^[1]

178

Net periodic benefit of defined benefit pension plans

534

581

591

(163)

(91)

(93)

Provision for doubtful receivables from clients

Benefit from deferred income taxes

(115)

(285)

(244)

Non-cash foreign exchange loss/(gain)

123

(28)

Net loss/(gain) on disposal of operations

(13)

Other, net

(57)

Changes in operating assets and liabilities, net of effects from purchase of subsidiaries:

Accounts receivable

(64)

(101)

(839)

(1,167)

(249)

839

1,167

249

Other assets

(22)

(128)

(233)

Other liabilities

(20)

(51)

174

Provisions

(23)

(35)

CASH FLOWS (USED IN)/FROM INVESTING ACTIVITIES

1,288

862

933

Additions to fixed assets and software for internal use

(268)

(300)

(218)

Acquisitions of operations, net of cash acquired

(54)

(75)

(85)

(36)

(13)

476

Net proceeds from sale of operations

(1)

Other, net

(4)

Net cash (used in)/from investing activities

(341)

(335)

195

CASH FLOWS USED IN FINANCING ACTIVITIES

Net (payments)/borrowings on revolving credit facility

(754)

642

(237)

Senior notes issued

998

649

1,606

Proceeds from issuance of other debt

404

Debt issuance costs

(8)

(9)

(14)

Repayments of debt

(170)

(734)

(1,901)

Repurchase of shares

(602)

(532)

(396)

Proceeds from issuance of shares

Payments related to share cancellation

(177)

Payments of deferred and contingent consideration related to acquisitions

(50)

(65)

(67)

Cash paid for employee taxes on withholding shares

(30)

(18)

(13)

Dividends paid

(306)

(277)

(199)

Acquisitions of and dividends paid to non-controlling interests

(26)

(51)

(21)

Net cash used in financing activities

(903)

(479)

(775)

INCREASE IN CASH AND CASH EQUIVALENTS

353

Effect of exchange rate changes on cash and cash equivalents

(41)

112

(15)

CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD

1,030

870

532

CASH AND CASH EQUIVALENTS, END OF PERIOD

$ 1,033

$ 1,030

$ 870

[1]	Depreciation expense included here does not equal the depreciation expense on the statements of comprehensive income for the years ended December 31, 2018 and 2017 due to the inclusion of $5 million and $49 million, respectively, which have been classified as transaction and integration expenses.

Consolidated Statements of Changes in Equity - USD ($)
shares in Thousands, $ in Millions

Total

Shares outstanding [Member]

Ordinary shares and APIC [Member]

Retained earnings [Member]

Treasury shares [Member]

AOCL [Member]

^[1]

Total WTW shareholders’ equity [Member]

Non-controlling interests [Member]

Redeemable Noncontrolling interests [Member]

Equity, beginning balance at Dec. 31, 2015

$ 2,360

$ 1,672

$ 1,597

$ (3)

$ (1,037)

$ 2,229

$ 131

Equity, beginning balance (in shares) at Dec. 31, 2015

68,625

Temporary equity, beginning balance at Dec. 31, 2015

^[2]

$ 53

Increase (Decrease) in Stockholders' Equity [Roll Forward]

Shares repurchased

(396)

(300)

(96)

(396)

Shares repurchased (in shares)

(3,170)

Net income

431

420

Net income, redeemable

^[2]

Net income, total

438

Dividends

(274)

(265)

(9)

(5)

^[2]

Other comprehensive (loss)/income

(863)

(847)

(16)

Other comprehensive (loss)/income, redeemable

^[2]

(4)

Other comprehensive (loss)/income, total

(867)

Issuance of shares under employee stock compensation plans

Issuance of shares under employee stock compensation plans (in shares)

1,342

Issuance of shares for acquisitions

8,686

Issuance of shares for acquisitions (in shares)

69,500

Replacement share-based compensation awards issued on acquisition

Additional non-controlling interests

123

Foreign currency translation

Equity, ending balance at Dec. 31, 2016

10,183

10,596

1,452

(99)

(1,884)

10,065

118

Equity, ending balance (in shares) at Dec. 31, 2016

136,297

Temporary equity, ending balance at Dec. 31, 2016

^[2]

Adoption of New Pronouncement (Accounting Standards Update 2016-16 [Member]) at Dec. 31, 2016

(3)

Increase (Decrease) in Stockholders' Equity [Roll Forward]

Shares repurchased

(532)

Shares repurchased (in shares)

(3,797)

Shares canceled

(177)

(96)

(177)

Shares canceled, shares

(1,415)

Net income

584

568

Net income, redeemable

^[2]

Net income, total

592

Dividends

(300)

(285)

(15)

(3)

^[2]

Other comprehensive (loss)/income

378

371

Other comprehensive (loss)/income, redeemable

^[2]

Other comprehensive (loss)/income, total

384

Issuance of shares under employee stock compensation plans

Issuance of shares under employee stock compensation plans (in shares)

1,055

Acquisition of non-controlling interests

(3)

(34)

^[2]

Foreign currency translation

(10)

Equity, ending balance at Dec. 31, 2017

10,249

^[3]

10,538

1,104

(3)

(1,513)

10,126

123

Equity, ending balance (in shares) at Dec. 31, 2017

132,140

Temporary equity, ending balance at Dec. 31, 2017

^[2]

Adoption of New Pronouncement (Accounting Standards Update 2014-09 [Member]) at Dec. 31, 2017

317

Increase (Decrease) in Stockholders' Equity [Roll Forward]

Shares repurchased

(602)

Shares repurchased (in shares)

(3,919)

Net income

713

695

Net income, redeemable

^[2]

Net income, total

715

Dividends

(337)

(313)

(24)

(2)

^[2]

Other comprehensive (loss)/income

(446)

(448)

Other comprehensive (loss)/income, redeemable

^[2]

(2)

Other comprehensive (loss)/income, total

(448)

Issuance of shares under employee stock compensation plans

Issuance of shares under employee stock compensation plans (in shares)

701

Foreign currency translation

Equity, ending balance at Dec. 31, 2018

$ 9,971

^[3]

$ 10,615

$ 1,201

$ (3)

$ (1,961)

$ 9,852

$ 119

Equity, ending balance (in shares) at Dec. 31, 2018

128,922

Temporary equity, ending balance at Dec. 31, 2018

^[2]

$ 26

[1]	Accumulated other comprehensive loss, net of tax (‘AOCL’)
[2]	The non-controlling interest is related to Max Matthiessen Holding AB.
[3]	Equity includes (a) Ordinary shares $0.000304635 nominal value; Authorized 1,510,003,775; Issued 128,921,530 (2018) and 132,139,581 (2017); Outstanding 128,921,530 (2018) and 132,139,581 (2017); (b) Ordinary shares, €1 nominal value; Authorized and Issued 40,000 shares in 2018 and 2017; and (c) Preference shares, $0.000115 nominal value; Authorized 1,000,000,000 and Issued none in 2018 and 2017.

Nature of Operations

12 Months Ended

Dec. 31, 2018

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Nature of Operations

Note 1 — Nature of Operations

Willis Towers Watson plc is a leading global advisory, broking and solutions company that helps clients around the world turn risk into a path for growth. The Company has more than 43,000 employees and services clients in more than 140 countries. We design and deliver solutions that manage risk, optimize benefits, cultivate talent, and expand the power of capital to protect and strengthen institutions and individuals. We believe our broad perspective allows us to see the critical intersections between talent, assets and ideas - the dynamic formula that drives business performance.

We offer our clients a broad range of services to help them identify and control their risks, and to enhance business performance by improving their ability to attract, retain and engage a talented workforce. Our risk control services range from strategic risk consulting (including providing actuarial analysis), to a variety of due diligence services, to the provision of practical on-site risk control services (such as health and safety or property loss control consulting), as well as analytical and advisory services (such as hazard modeling and reinsurance optimization studies). We assist clients in planning how to manage incidents or crises when they occur. These services include contingency planning, security audits and product tampering plans. We help our clients enhance their business performance by delivering consulting services, technology and solutions that help them anticipate, identify and capitalize on emerging opportunities in human capital management as well as offer investment advice to help them develop disciplined and efficient strategies to meet their investment goals.

As an insurance broker, we act as an intermediary between our clients and insurance carriers by advising our clients on their risk management requirements, helping them to determine the best means of managing risk and negotiating and placing insurance with insurance carriers through our global distribution network. We operate a private Medicare exchange in the U.S. Through this exchange and those for active employees, we help our clients move to a more sustainable economic model by capping and controlling the costs associated with healthcare benefits.

We are not an insurance company, and therefore we do not underwrite insurable risks for our own account.

Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements

Note 2 — Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements

Basis of Presentation

The accompanying audited consolidated financial statements of Willis Towers Watson and our subsidiaries are presented in accordance with the rules and regulations of the SEC for annual reports on Form 10-K and are prepared in accordance with U.S. GAAP. All intercompany accounts and transactions have been eliminated in consolidation. We have reclassified certain prior year amounts to conform to the current year presentation.

Significant Accounting Policies

Principles of Consolidation — The accompanying consolidated financial statements include the accounts of Willis Towers Watson and those of our majority-owned and controlled subsidiaries. Intercompany accounts and transactions have been eliminated.

We determine whether we have a controlling financial interest in an entity by first evaluating whether the entity is a voting interest entity or a variable interest entity (‘VIE’). Variable interest entities are entities that lack one or more of the characteristics of a voting interest entity and therefore require a different approach in determining which party involved with the VIE should consolidate the entity. With a VIE, either the entity does not have sufficient equity at risk to finance its activities without additional subordinated financial support from other parties, or the equity holders, as a group, do not have the power to direct the activities that most significantly impact its financial performance, the obligation to absorb expected losses of the entity, or the right to receive the expected residual returns of the entity. The entity that has a controlling financial interest in a VIE is referred to as the primary beneficiary and is required to consolidate the VIE.

Voting interest entities are entities that have sufficient equity and provide equity investors voting rights that give them the power to make significant decisions related to the entity’s operations. The usual condition for a controlling financial interest in a voting interest entity is ownership of a majority voting interest. Accordingly, we consolidate our voting interest entity investments in which we hold, directly or indirectly, more than 50% of the voting rights.

Use of Estimates — These consolidated financial statements conform to U.S. GAAP, which requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities as well as disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting periods. Our estimates, judgments and assumptions are continually evaluated based on available information and experience. Because of the use of estimates inherent in the financial reporting process, actual results could differ from those estimates. Estimates are used when accounting for revenue recognition and related costs, the selection of useful lives of fixed and intangible assets, impairment testing, valuation of billed and unbilled receivables from clients, discretionary compensation, income taxes, pension assumptions, incurred but not reported claims, legal reserves and goodwill and intangible assets.

Going Concern — Management evaluates at each annual and interim period whether there are conditions or events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern within one year after the date that the consolidated financial statements are issued. Management’s evaluation is based on relevant conditions and events that are known and reasonably knowable at the date that the consolidated financial statements are issued. Management has concluded that there are no conditions or events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern within one year after the date of these financial statements.

Fair Value of Financial Instruments — The carrying values of our cash and cash equivalents, accounts receivable, accrued expenses, revolving lines of credit and term loans approximate their fair values because of the short maturity and liquidity of those instruments. We consider the difference between carrying value and fair value to be immaterial for our senior notes. The fair value of our senior notes are considered Level 2 financial instruments as they are corroborated by observable market data. See Note 12 — Fair Value Measurements for additional information about our measurements of fair value.

Investments in Associates — Investments are accounted for using the equity method of accounting, included within other non-current assets in the consolidated balance sheets, if the Company has the ability to exercise significant influence, but not control, over the investee. Significant influence is generally deemed to exist if the Company has an equity ownership in the voting stock of the investee between 20 and 50 percent, although other factors, such as representation on the board of directors, the existence of substantive participation rights, and the impact of commercial arrangements, are considered in determining whether the equity method of accounting is appropriate. Under the equity method of accounting, the investment is carried at the cost of acquisition, plus the Company’s equity in undistributed net income since acquisition, less any dividends received since acquisition.

The Company periodically reviews its investments in associates for which fair value is less than cost to determine if the decline in value is other than temporary. If the decline in value is judged to be other than temporary, the cost basis of the investment is written down to fair value. The amount of any write-down is included in the consolidated statements of comprehensive income.

Common Shares Split — On January 4, 2016, the Company effected a 1 to 2.6490 reverse share split to shareholders of record as of January 4, 2016. All share and per share information has been retroactively adjusted to reflect the reverse share split and show the new number of shares. See Note 3 — Merger, Acquisitions and Divestitures for additional information about our Merger and reverse share split.

Cash and Cash Equivalents — Cash and cash equivalents primarily consist of time deposits with original maturities of 90 days or less. In certain of the countries in which we conduct business, we are subject to capital adequacy requirements. Most significantly, Willis Limited, our U.K. brokerage subsidiary regulated by the Financial Conduct Authority, is currently required to maintain $140 million in unencumbered and available financial resources, of which at least $79 million must be in cash, for regulatory purposes. Term deposits and certificates of deposits with original maturities greater than 90 days are considered to be short-term investments. There is no restricted cash included in our cash and cash equivalents balance, as these amounts are included in fiduciary assets.

Fiduciary Assets and Liabilities — The Company collects premiums from insureds and, after deducting commissions, remits the premiums to the respective insurers. The Company also collects claims or refunds from insurers on behalf of insureds. Certain of our health and welfare benefits administration outsourcing agreements require us to hold funds on behalf of clients to pay obligations on their behalf. Each of these transactions is reported on our consolidated balance sheet as assets and corresponding liabilities unless such balances are due to or from the same party and a right of offset exists, in which case the balances are recorded net.

Fiduciary assets on the consolidated balance sheets are comprised of both fiduciary funds and fiduciary receivables:

Fiduciary Funds – Unremitted insurance premiums and claims are recorded within fiduciary assets on the consolidated balance sheets. Fiduciary funds are generally required to be kept in certain regulated bank accounts subject to guidelines which emphasize capital preservation and liquidity. Such funds are not available to service the Company’s debt or for other corporate purposes. Notwithstanding the legal relationships with insureds and insurers, the Company is entitled to retain investment income earned on fiduciary funds in accordance with industry custom and practice and, in some cases, as supported by agreements with insureds. The period for which the Company holds such funds is dependent upon the date the insured remits the payment of the premium to the Company, or the date the Company receives refunds from the insurers, and the date the Company is required to forward such payments to the insurer or insured, respectively.

Fiduciary receivables – Uncollected premiums from insureds and uncollected claims or refunds from insurers are recorded as fiduciary assets on the consolidated balance sheets. In certain instances, the Company advances premiums, refunds or claims to insurance underwriters or insureds prior to collection. Such advances are made from fiduciary funds and are reflected in the consolidated balance sheets as fiduciary assets.

Fiduciary liabilities on the consolidated balance sheets represent the obligations to remit all fiduciary funds and fiduciary receivables to insurers or insureds.

Accounts Receivable — Accounts receivable includes both billed and unbilled receivables and is stated at estimated net realizable values. Provision for billed receivables is recorded, when necessary, in an amount considered by management to be sufficient to meet probable future losses related to uncollectible accounts. Accrued and unbilled receivables are stated at net realizable value which includes an allowance for accrued and unbillable amounts. See Note 4 — Revenue for additional information about our accounts receivable.

Income Taxes — The Company recognizes deferred tax assets and liabilities for the estimated future tax consequences of events attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating and capital loss and tax credit carry forwards. Deferred tax assets and liabilities are measured using enacted rates in effect for the year in which the differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of changes in tax rates is recognized in the consolidated statement of comprehensive income in the period in which the change is enacted. Deferred tax assets are reduced through the establishment of a valuation allowance at such time as, based on available evidence, it is more likely than not that the deferred tax assets will not be realized. The Company adjusts valuation allowances to measure deferred tax assets at the amounts considered realizable in future periods if the Company’s facts and assumptions change. In making such determinations, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax planning strategies and the results of recent financial operations. We place more reliance on evidence that is objectively verifiable.

Positions taken in the Company’s tax returns may be subject to challenge by the taxing authorities upon examination. The Company recognizes the benefit of uncertain tax positions in the financial statements when it is more likely than not that the position will be sustained on the basis of the technical merits of the position assuming the tax authorities have full knowledge of the position and all relevant facts. Recognition also occurs upon either the lapse of the relevant statute of limitations, or when positions are effectively settled. The benefit recognized is the largest amount of tax benefit that is greater than 50 percent likely to be realized on settlement with the tax authority. The Company adjusts its recognition of uncertain tax benefits in the period in which new information is available impacting either the recognition or measurement of its uncertain tax positions. Such adjustments are reflected as increases or decreases to income taxes in the period in which they are determined.

The Company recognizes interest and penalties relating to unrecognized tax benefits within income taxes. See Note 7 — Income Taxes for additional information regarding the Company’s income taxes.

Foreign Currency — Transactions in currencies other than the functional currency of the entity are recorded at the rates of exchange prevailing at the date of the transaction. Monetary assets and liabilities in currencies other than the functional currency are translated at the rates of exchange prevailing at the balance sheet date and the related transaction gains and losses are reported as income or expense in the consolidated statements of comprehensive income. Certain intercompany loans are determined to be of a long-term investment nature. The Company records transaction gains and losses from re-measuring such loans as other comprehensive income in the consolidated statements of comprehensive income.

Upon consolidation, the results of operations of subsidiaries and associates whose functional currency is other than the U.S. dollar are translated into U.S. dollars at the average exchange rates and assets and liabilities are translated at year-end exchange rates. Translation adjustments are presented as a separate component of other comprehensive income in the financial statements and are included in net income only upon sale or liquidation of the underlying foreign subsidiary or associated company.

Derivatives — The Company uses derivative financial instruments for other than trading purposes to alter the risk profile of an existing underlying exposure. Interest rate swaps have been used to manage interest risk exposures. Forward foreign currency exchange contracts are used to manage currency exposures arising from future income and expenses. The fair values of derivative contracts are recorded in other assets and other liabilities in the consolidated balance sheets. The effective portions of changes in the fair value of derivatives that qualify for hedge accounting as cash flow hedges are recorded in other comprehensive income. Amounts are reclassified from other comprehensive income into earnings when the hedged exposure affects earnings. If the derivative is designated and qualifies as an effective fair value hedge, the changes in the fair value of the derivative and of the hedged item associated with the hedged risk are both recognized in earnings. The amount of hedge ineffectiveness recognized in earnings is based on the extent to which an offset between the fair value of the derivative and hedged item is not achieved. Changes in fair value of derivatives that do not qualify for hedge accounting, together with any hedge ineffectiveness on those that do qualify, are recorded in other income, net or interest expense as appropriate.

The Company evaluates whether its contracts include clauses or conditions which would be required to be separately accounted for at fair value as embedded derivatives. See Note 10 — Derivative Financial Instruments for additional information about the Company’s derivatives.

Commitments, Contingencies and Provisions for Liabilities — The Company establishes provisions against various actual and potential claims, lawsuits and other proceedings relating principally to alleged errors and omissions in the ordinary course of business. Such provisions cover claims that have been reported but not paid and also unasserted claims and related legal fees. These provisions are established based on actuarial estimates together with individual case reviews and are believed to be adequate in light of current information and legal advice. In certain cases, where a range of loss exists, we accrue the minimum amount in the range if no amount within the range is a better estimate than any other amount. To the extent such losses can be recovered under the Company’s insurance programs, estimated recoveries are recorded when losses for insured events are recognized and the recoveries are likely to be realized. Significant management judgment is required to estimate the amounts of such unasserted claims and the related insurance recoveries. The Company analyzes its litigation exposure based on available information, including consultation with outside counsel handling the defense of these matters, to assess its potential liability. These contingent liabilities are not discounted. See Note 14 — Commitments and Contingencies and Note 15 — Supplementary Information for Certain Balance Sheet Accounts for additional information about our commitments, contingencies and provisions for liabilities.

Share-Based Compensation — The Company has equity-based compensation plans that provide for grants of restricted stock units and stock options to employees and non-employee directors of the Company. Additionally, the Company has cash-settled share-based compensation plans that provide for grants to employees.

The Company expenses equity-based compensation, which is included in Salaries and benefits in the consolidated statements of comprehensive income, primarily on a straight-line basis over the requisite service period. The significant assumptions underlying our expense calculations include the fair value of the award on the date of grant, the estimated achievement of any performance targets and estimated forfeiture rates. The awards under equity-based compensation are classified as equity and are included as a component of equity on the Company’s consolidated balance sheets, as the ultimate payment of such awards will not be achieved through use of the Company’s cash or other assets.

For the cash-settled share-based compensation, the Company recognizes a liability for the fair-value of the awards as of each reporting date included within other non-current liabilities in the consolidated balance sheets. Expense is recognized over the service period, and as the liability is remeasured at the end of each reporting period, changes in fair value are recognized as compensation cost within Salaries and benefits in the consolidated statements of comprehensive income. The significant assumptions underlying our expense calculations include the estimated achievement of any performance targets and estimated forfeiture rates.

See Note 18 — Share-based Compensation for additional information about the Company’s share-based compensation.

Fixed Assets — Fixed assets are stated at cost less accumulated depreciation. Expenditures for improvements are capitalized; repairs and maintenance are charged to expense as incurred. Depreciation is computed primarily using the straight-line method based on the estimated useful lives of assets.

Depreciation on internally-developed software is amortized over the estimated useful life of the asset ranging from 3 to 10 years. Buildings include assets held under capital leases and are depreciated over the lesser of 50 years, the asset lives or the lease terms. Depreciation on leasehold improvements is calculated over the lesser of the useful lives of the assets or the remaining lease terms. Depreciation on furniture and equipment is calculated based on a range of 3 to 10 years. Land is not depreciated.

Long-lived assets are tested for recoverability whenever events or changes in circumstance indicate that their carrying amounts may not be recoverable. An impairment loss is recognized if the carrying amount of a long-lived asset is not recoverable and exceeds its fair value. Recoverability is determined based on the undiscounted cash flows expected to result from the use and eventual disposition of the asset or asset group. Long-lived assets and certain identifiable intangible assets to be disposed of are reported at the lower of carrying amount or fair value less cost to sell. See Note 8 — Fixed Assets for additional information about our fixed assets.

Operating Leases — Rentals payable on operating leases are charged on a straight-line basis to Other operating expenses in the consolidated statements of comprehensive income over the lease terms. See Note 14 — Commitments and Contingencies for additional information about our operating leases.

Goodwill and Other Intangible Assets — In applying the acquisition method of accounting for business combinations, amounts assigned to identifiable assets and liabilities acquired were based on estimated fair values as of the date of acquisition, with the remainder recorded as goodwill. Intangible assets are initially valued at fair value using generally accepted valuation methods appropriate for the type of intangible asset. Intangible assets with definite lives are amortized over their estimated useful lives and are reviewed for impairment if indicators of impairment arise. Intangible assets with indefinite lives are tested for impairment annually as of October 1, and whenever indicators of impairment exist. The fair values of intangible assets are compared with their carrying values, and an impairment loss would be recognized for the amount by which a carrying amount exceeds its fair value.

Acquired intangible assets are amortized over the following periods:



	Amortization basis	Expected life (years)
Client relationships	In line with underlying cash flows	5 to 20
Software	In line with underlying cash flows or straight-line basis	4 to 7
Product	In line with underlying cash flows	17.5
Trademark and trade name	Straight-line basis	14 to 25
Favorable agreements	Straight-line basis	7
Management contracts	Straight-line basis	18

Goodwill is tested for impairment annually as of October 1, and whenever indicators of impairment exist. Goodwill is tested at the reporting unit level, and the Company had nine reporting units as of October 1, 2018. In the first step of the impairment test, the fair value of each reporting unit is compared with its carrying value, including goodwill. If the carrying value of a reporting unit exceeds its fair value, the amount of an impairment loss, if any, is calculated in the second step of the impairment test by comparing the implied fair value of reporting unit goodwill with the carrying amount of that goodwill. The Company’s goodwill impairment tests for the years ended December 31, 2018 and 2017 have not resulted in any impairment charges. See Note 9 — Goodwill and Other Intangible Assets for additional information about our goodwill and other intangible assets.

Pensions — The Company has multiple defined benefit pension and defined contribution plans. The net periodic cost of the Company’s defined benefit plans is measured on an actuarial basis using various methods and actuarial assumptions. The most significant assumptions are the discount rates (calculated using the granular approach to calculating service and interest cost) and the expected long-term rates of return on plan assets. Other material assumptions include rates of participant mortality, the expected long-term rates of compensation and pension increases and rates of employee termination. Gains and losses occur when actual experience differs from actuarial assumptions. If such gains or losses exceed ten percent of the greater of the market-related value of plan assets or the projected benefit obligation, the Company amortizes those gains or losses over the average remaining service period or average remaining life expectancy, as appropriate, of the plan participants. In accordance with U.S. GAAP, the Company records on its consolidated balance sheets the funded status of its pension plans based on the projected benefit obligation.

Contributions to the Company’s defined contribution plans are recognized as incurred. Differences between contributions payable in the year and contributions actually paid are shown as either other assets or other liabilities in the consolidated balance sheets. See Note 13 — Retirement Benefits for additional information about our pensions.

Revenue Recognition (effective from January 1, 2018) — The following policies were effective for the 2018 fiscal year as a result of the adoption, on January 1, 2018, of ASC 606, Revenue From Contracts With Customers (‘ASC 606’). The revenue recognition policies in effect prior to 2018 are reflected in the next section.

We recognize revenue from a variety of services, with broking, consulting and outsourced administration representing our most significant offerings. All other revenue streams, which can be recognized at either point in time or over time, are individually less significant and are grouped in Other in our revenue disaggregation disclosures in Note 4 — Revenue. These Other revenue streams represent approximately 5% of customer contract revenue for the year ended December 31, 2018.

Broking — Representing approximately 48% of customer contract revenue for the year ended December 31, 2018, in our broking arrangements, we earn revenue by acting as an intermediary in the placement of effective insurance policies. Generally, we act as an agent and view our client to be the party looking to obtain insurance coverage for various risks, or an employer or sponsoring organization looking to obtain insurance coverage for its employees or members. Also, we act as an agent in reinsurance broking arrangements where our client is the party looking to cede risks to the reinsurance markets. Our primary performance obligation under the majority of these arrangements is to place an effective insurance or reinsurance policy, but there can also be significant post-placement obligations in certain contracts to which we need to allocate revenue. The most common of these is for claims handling or call center support. The revenue recognition method for these, after the relative fair value allocation, is described further as part of the ‘Outsourced Administration’ description below.

Due to the nature of the majority of our broking arrangements, no single document constitutes the contract for ASC 606 purposes. Our services may be governed by a mixture of different types of contractual arrangements depending on the jurisdiction or type of coverage, including terms of business agreements, broker-of-record letters, statements of work or local custom and practice. This is then confirmed by the client’s acceptance of the underlying insurance contract. Prior to the policy inception date, the client has not accepted nor formally committed to perform under the arrangement (i.e. pay for the insurance coverage in place). Therefore in the majority of broking arrangements, the contract date is the date the insurance policy incepts. However, in certain instances such as Medicare broking or Affinity arrangements, where the employer or sponsoring organization is our customer, client acceptance of underlying individual policy placements is not required, and therefore the date at which we have a contract with a customer is not dependent upon placement.

As noted, our primary performance obligations typically consist of only the placement of an effective insurance policy which precedes the inception date of the policy. Therefore, most of our fulfillment costs are incurred before we can recognize revenue, and are thus deferred during the pre-placement process. Where we have material post-placement services obligations, we estimate the relative fair value of the post-placement services using either the expected cost-plus-margin or the market assessment approach.

Fees for our broking services consist of commissions or fees negotiated in lieu of commissions. At times, we may receive additional income for performing these services from the insurance and reinsurance carriers’ markets, which is collectively referred to as ‘market derived income’. In situations in which our fees are not fixed but are variable, we must estimate the likely commission per policy, taking into account the likelihood of cancellation before the end of the policy. For Medicare broking, Affinity arrangements and proportional treaty reinsurance broking, the commissions to which we will be entitled can vary based on the underlying individual insurance policies that are placed. For Medicare broking and proportional treaty reinsurance broking in particular, we base the estimates of transaction prices on supportable evidence from an analysis of past transactions, and only include amounts that are probable of being received or not refunded (referred to as applying ‘constraint’ under ASC 606). This is an area requiring significant judgment and results in us estimating a transaction price that may be significantly lower than the ultimate amount of commissions we may collect. The transaction price is then adjusted over time as we receive confirmation of our remuneration through receipt of treaty statements, or as other information becomes available.

We recognize revenue for most broking arrangements as of a point in time at the later of the policy inception date or when the policy placement is complete, because this is viewed as the date when control is transferred to the client. For Medicare broking, we recognize revenue over time, as we stand ready under our agreements to place retiree Medicare coverage. For this type of broking arrangement, we recognize the majority of our placement revenue in the fourth quarter of the calendar year when the majority of the placement or renewal activity occurs.

Consulting — We earn revenue for advisory and consulting work that may be structured as different types of service offerings, including annual recurring projects, projects of a short duration or stand-ready obligations. Collectively, our consulting arrangements represent approximately 34% of customer contract revenue for the year ended December 31, 2018.

We have engagement letters with our clients that specify the terms and conditions upon which the engagements are based. These terms and conditions can only be changed upon agreement by both parties.

In assessing our performance obligations, our consulting work is typically highly integrated, with the various promised services representing inputs of the combined overall output. We view these arrangements to represent a single performance obligation. To the extent we do not integrate our services, as is the case with unrelated services that may be sourced from different areas of our business, we consider these separate performance obligations.

Fee terms can be in the form of fixed-fees (including fixed-fees offset by commissions), time-and-expense fees, commissions, per-participant fees, or fees based on assets under management. Payment is typically due on a monthly basis as we perform under the contract, and we are entitled to be reimbursed for work performed to date in the event of termination.

The majority of our revenue from these consulting engagements is recognized over time, either because our clients are simultaneously receiving and consuming the benefits of our services, or because we have an enforceable right to payment for performance rendered to date. Additionally, from time to time, we may be entitled to an additional fee based on achieving certain performance criteria. To the extent that we cannot estimate with reasonable assurance the likelihood that we will achieve the performance target, we will ‘constrain’ this portion of the transaction price and recognize it when or as the uncertainty is resolved.

We use different progress measures to determine our revenue depending on the nature of the engagement:

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Annual recurring projects and projects of short duration. These projects are typically straightforward and highly predictable in nature with either time-and-expense or fixed fee terms. Time-and-expense fees are recognized as hours or expenses are incurred using the ‘right to invoice’ practical expedient allowed under ASC 606. For fixed-fee arrangements, to the extent estimates can be made of the remaining work required under the arrangement, revenue is based upon the proportional performance method, using the value of labor hours compared to the estimated total value of labor hours. We believe that cost represents a faithful depiction of transfer of value because the completion of these performance obligations is based upon the professional services of employees of differing experience levels and thereby costs. It is appropriate that satisfaction of these performance obligations considers both the number of hours incurred by each employee and the value of each labor hour worked (as opposed to simply the hours worked).

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Stand-ready obligations. These projects consist of repetitive monthly or quarterly services performed consistently each period. As none of the activities provided under these services are performed at specified times and quantities, but at the discretion of each customer, our obligation is to stand ready to perform these services on an as-needed basis. These arrangements represent a ‘series’ performance obligation in accordance with ASC 606. Each time increment (i.e. each month or quarter) of standing ready to provide the overall services is distinct and the customer obtains value from each period of service independent of the other periods of service.

Where we recognize revenue on a proportional performance basis, the amount we recognize is affected by a number of factors that can change the estimated amount of work required to complete the project such as the staffing on the engagement and/or the level of client participation. Our periodic engagement evaluations require us to make judgments and estimates regarding the overall profitability and stage of project completion that, in turn, affect how we recognize revenue. We recognize a loss on an engagement when estimated revenue to be received for that engagement is less than the total estimated costs associated with the engagement. Losses are recognized in the period in which the loss becomes probable and the amount of the loss is reasonably estimable.

Outsourced Administration — We provide customized benefits outsourcing and co-sourcing solutions services in relation to the administration of defined benefit, defined contribution, and health and welfare plans. These plans are sponsored by our clients to provide benefits to their active or retired employees. Additionally, these services include operating call centers, and may include providing access to, and managing a variety of consumer-directed savings accounts. The operation of call centers and consumer-directed accounts can be provisioned as part of an ongoing administration or solutions service, or separately as part of a broking arrangement. The products and services available to all clients are the same, but the selections by the client can vary and portray customized products and services based on the customer’s specific needs. Our services often include the use of proprietary systems that are configured for each of our clients’ needs. In total, our outsourced administration services represent approximately 12% of customer contract revenue for the year ended December 31, 2018.

These contracts typically consist of an implementation phase and an ongoing administration phase:

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Implementation phase. Work performed during the implementation phase is considered a set-up activity because it does not transfer a service to the customer, and therefore costs are deferred during this phase of the arrangement. Since these arrangements are longer term in nature and subject to more changes in scope as the project progresses, our contracts generally provide that if the client terminates a contract, we are entitled to an additional payment for services performed through the termination date designed to recover our up-front costs of implementation.

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Ongoing administration phase. The ongoing administration phase includes a variety of plan administration services, system hosting and support services. More specifically, these services include data management, calculations, reporting, fulfillment/communications, compliance services, call center support, and in our health and welfare arrangements, annual onboarding and enrollment support. While there are a variety of activities performed, the overall nature of the obligation is to provide an integrated outsourcing solution to the customer. The arrangement represents a stand-ready obligation to perform these activities on an as-needed basis. The customer obtains value from each period of service, and each time increment (i.e., each month, or each benefits cycle in our health and welfare arrangements) is distinct and substantially the same. Accordingly, the ongoing administration services represent a ‘series’ in accordance with ASC 606 and are deemed one performance obligation.

We have engagement letters with our clients that specify the terms and conditions upon which the engagements are based. These terms and conditions can only be changed upon agreement by both parties. Fees for these arrangements can be fixed, per-participant-per-month, or in the case of call center services provided in conjunction with our broking services, an allocation based on commissions. Our fees are not typically payable until the commencement of the ongoing administration phase. However, in our health and welfare arrangements, we begin transferring services to our customers approximately four months prior to payments being due as part of our annual onboarding and enrollment work. Although our per-participant-per-month and commission-based fees are considered variable, they are typically predictable in nature, and therefore we generally do not ‘constrain’ any portion of our transaction price estimates. Once fees become payable, payment is typically due on a monthly basis as we perform under the contract, and are entitled to be reimbursed for work performed to date in the event of termination.

Revenue is recognized over time as the services are performed because our clients are simultaneously receiving and consuming the benefits of our services. For our health and welfare arrangements where each benefits cycle represents a time increment under the series guidance, revenue is recognized based on proportional performance. We use an input measure (value of labor hours worked) as the measure of progress. Given that the service is stand-ready in nature, it can be difficult to predict the remaining obligation under the benefits cycle. Therefore, the input measure is based on the historical effort expended each month, which is measured as labor cost. This results in slightly more revenue being recognized during periods of annual onboarding since we are performing both our normal monthly services and our annual services during this portion of the benefits cycle.

For all other outsourced administration arrangements where a month represents our time increment under the series guidance, we allocate transaction price to the month we are performing our services. Therefore, the amount recognized each month is the variable consideration related to that month plus the fixed monthly or annual fee. The fixed monthly or annual fee is recognized on a straight-line basis. Revenue recognition for these types of arrangements is therefore more consistent throughout the year.

Reimbursed expenses — Client reimbursable expenses, including those relating to travel, other out-of-pocket expenses and any third-party costs, are included in revenue, and an equivalent amount of reimbursable expenses is included in other operating expenses as a cost of revenue as incurred. Reimbursed expenses represented approximately 1% of customer contract revenue for the year ended December 31, 2018. Taxes collected from customers and remitted to government authorities are recorded net and are excluded from revenue.

Revenue Recognition (effective before January 1, 2018) — Revenue included insurance commissions, fees in lieu of commission, fees for consulting services rendered, hosted and delivered software, survey sales, interest and other income.

Revenue recognized in excess of billings was recorded as unbilled accounts receivable. Cash collections in excess of revenue recognized were recorded as deferred revenue until the revenue recognition criteria were met. Client reimbursable expenses, including those relating to travel, other out-of-pocket expenses and any third-party costs, were included in revenue, and an equivalent amount of reimbursable expenses was included in other operating expenses as a cost of revenue. Taxes collected from customers and remitted to government authorities were recorded net and were excluded from revenue.

Commissions revenue. Brokerage commissions and fees negotiated in lieu of commissions were recognized at the later of the policy inception date or when the policy placement was complete. In situations in which our fees were not fixed and determinable due to the uncertainty of the commission fee per policy, we recognized revenue as the fees were determined. Commissions on additional premiums and adjustments were recognized when approved by or agreed between the parties and collectability was reasonably assured.

Consulting revenue. The majority of our consulting revenue consisted of fees earned from providing consulting services. We recognized revenue from these consulting engagements when hours were worked, either on a time-and-expense basis or on a fixed-fee basis, depending on the terms and conditions defined at the inception of an engagement with a client. We had engagement letters with our clients that specified the terms and conditions upon which the engagements were based. These terms and conditions could only be changed upon agreement by both parties. Individual billing rates were principally based on a multiple of salary and compensation costs.

Revenue for fixed-fee arrangements was based upon the proportional performance method to the extent estimates could be made of the remaining work required under the arrangement. If we did not have sufficient information to estimate proportional performance, we recognized the fees straight-line over the contract period. We typically had four types of fixed-fee arrangements: annual recurring projects, projects of a short duration, stand-ready obligations and non-recurring system projects.

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Annual recurring projects and projects of short duration. These projects were typically straightforward and highly predictable in nature. As a result, the project manager and financial staff were able to identify, as the project status was reviewed and bills were prepared monthly, the occasions when cost overruns could lead to the recording of a loss accrual.

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Stand-ready obligations. Where we were entitled to fees (whether fixed or variable based on assets under management or a per-participant per-month basis) regardless of the hours, we generally recognized this revenue on either a straight-line basis or as the variable fees were calculated.

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Non-recurring system projects. These projects were longer in duration and subject to more changes in scope as the project progressed. Certain software or outsourced administration contracts generally provided that if the client terminated a contract, we were entitled to an additional payment for services performed through termination designed to recover our up-front cost of implementation.

Revenue recognition for fixed-fee engagements was affected by a number of factors that changed the estimated amount of work required to complete the project such as changes in scope, the staffing on the engagement and/or the level of client participation. The periodic engagement evaluations required us to make judgments and estimates regarding the overall profitability and stage of project completion that, in turn, affected how we recognized revenue. We recognized a loss on an engagement when estimated revenue to be received for that engagement was less than the total estimated costs associated with the engagement. Losses were recognized in the period in which the loss became probable and the amount of the loss was reasonably estimable.

Hosted software. We develop various software programs and technologies that we provide to clients in connection with consulting services. In most instances, such software is hosted and maintained by us and ownership of the technology and rights to the related code remain with us. We deferred costs for software developed to be utilized in providing services to a client, but for which the client did not have the contractual right to take possession, during the implementation stage. We recognized these deferred costs from the go-live date, signaling the end of the implementation stage, until the end of the initial term of the contract with the client. We determined that the system implementation and customized ongoing administrative services were one combined service. Revenue was recognized over the service period, after the go-live date, on a straight-line basis. As a result, we did not recognize revenue during the implementation phase of an engagement.

Delivered software. We deliver software under arrangements with clients who take possession of our software. The maintenance associated with the initial software fees is a fixed percentage which enabled us to determine the stand-alone value of the delivered software separate from the maintenance. We recognized the initial software fees as software was delivered to the client, and we recognized the maintenance fees ratably over the contract period based on each element’s relative fair value. For software arrangements in which initial fees were received in connection with mandatory maintenance for the initial software license to remain active, we determined that the initial maintenance period was substantive. Therefore, we recognized the fees for the initial license and maintenance bundle ratably over the initial contract term, which was generally one year. Each subsequent renewal fee was recognized ratably over the contractually-stated renewal period.

Surveys. We collect, analyze and compile data in the form of surveys for our clients who have the option of participating in the survey. The surveys are published online via a web tool that provides simplistic functionality. We determined that the web tool was inconsequential to the overall arrangement. We recorded the survey revenue when the results were delivered online and made available to our clients who had a contractual right to the data. If the data was updated more frequently than annually, we recognized the survey revenue ratably over the contractually-stated period.

Interest income — Interest income is recognized as earned.

Other income — Other income includes gains on disposal of intangible assets, which primarily arise from settlements through enforcing non-compete agreements in the event of losing accounts through producer defection or the disposal of books of business.

Cost to obtain or fulfill contracts (effective from January 1, 2018) — Costs to obtain customers include commissions for brokers under specific agreements that would not be incurred without a contract being signed and executed. The Company has elected to apply the ASC 606 ‘practical expedient’ which allows us to expense these costs as incurred if the amortization period related to the resulting asset would be one year or less. The Company has no significant instances of contracts that would be amortized for a period greater than a year, and therefore has no contract costs capitalized for these arrangements.

Costs to fulfill include costs incurred by the Company that are expected to be recovered within the expected contract period. The costs associated with our system implementation activities and consulting contracts are recorded through time entry.

For our broking business, the Company must estimate the fulfillment costs incurred during the pre-placement of the broking contracts. These judgments include:

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which activities in the pre-placement process should be eligible for capitalization;

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the amount of time and effort expended on those pre-placement activities;

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the amount of payroll and related costs eligible for capitalization; and,

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the monthly timing of underlying insurance and reinsurance policy inception dates.

We amortize costs to fulfill over the period we receive the related benefits. For broking pre-placement costs, this is typically less than a year. In our system implementation and consulting arrangements, we include the likelihood of contract renewals in our estimate of the amortization period, resulting in most costs being amortized for a greater length of time than the initial contract term.

Recent Accounting Pronouncements

Not yet adopted

In February 2016, the FASB issued ASU No. 2016-02, Leases, which requires a lessee to recognize in the statement of financial position a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term. Additional ASUs have since been issued which provide amended and additional guidance for the implementation of ASU No. 2016-02. All related guidance has been codified into, and is now known as, ASC 842, Leases (‘ASC 842’). ASC 842 became effective for the Company at the beginning of its 2019 calendar year, at which time the Company adopted it.

As a result of finalizing and analyzing our inventory of lease agreements to determine the full impact this standard will have on the consolidated financial statements, processes and systems, the Company has determined the following:

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The Company will adopt the standard using the modified retrospective approach whereby it will recognize a transition adjustment at the effective date of ASC 842, January 1, 2019, rather than at the beginning of the earliest comparative period presented.

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We will reflect additional operating lease liabilities at the transition date of approximately $1.2 billion, as well as right-of-use assets of approximately $1.0 billion and an immaterial adjustment to retained earnings.

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We have assessed the transition practical expedients available under the guidance and, in addition to selecting the modified retrospective transition approach as noted above, we have made the following elections:

Practical expedient package - We have elected this package, and therefore we will not reassess lease classification for our existing or expired leases, whether any existing or expired contracts contain a lease, or our treatment of any initial direct costs.

Hindsight practical expedient – We have elected this practical expedient, and therefore will not revisit our estimate of lease terms upon transition to ASC 842.

Short-term lease exemption – We have elected this exemption, and will therefore not recognize any right-of-use assets or liabilities for short-term leases (generally defined as having a term of 12 months or less) on our consolidated balance sheet.

Separation of lease and non-lease components – We have elected the practical expedient to not separate the cash flows associated with lease and non-lease components in our lease accounting and resulting amounts recorded in our consolidated financial statements.

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Additionally, to prepare for the other required disclosures and new accounting treatment, the Company has implemented additional tools for its lease accounting and data collection processes, which were in place and effective on January 1, 2019.

In January 2017, the FASB issued ASU No. 2017-04, Simplifying the Test for Goodwill Impairment, which simplifies the subsequent measurement of goodwill by eliminating Step 2 from the goodwill impairment test. In computing the implied fair value of goodwill under Step 2, current U.S. GAAP requires the performance of procedures to determine the fair value at the impairment testing date of assets and liabilities (including unrecognized assets and liabilities) following the procedure that would be required in determining the fair value of assets acquired and liabilities assumed in a business combination. Instead, the amendments under this ASU require the goodwill impairment test to be performed by comparing the fair value of a reporting unit with its carrying amount. An impairment charge would be recognized for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. The ASU becomes effective for the Company on January 1, 2020. The amendments in this ASU should be applied on a prospective basis. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017, and the Company is still evaluating when to adopt this ASU. The Company does not expect an immediate impact to its consolidated financial statements upon adopting this ASU since the most recent Step 1 goodwill impairment test resulted in fair values in excess of carrying values for all reporting units at October 1, 2018.

In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities, which provides amendments under six specific objectives to better align risk management activities and financial reporting, and to simplify disclosure, presentation, hedging and the testing and measurement of ineffectiveness. The ASU became effective for the Company on January 1, 2019, at which time we adopted it. The Company does not believe adopting this ASU will have a material impact on its consolidated financial statements.

In February 2018, the FASB issued ASU No. 2018-02, Income Statement - Reporting Comprehensive Income: Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, which allows for a reclassification from accumulated other comprehensive income to retained earnings for ‘stranded’ tax effects (those tax effects of items within accumulated other comprehensive income resulting from the historical corporate income tax rate reduction) resulting from U.S. Tax Reform. The amendments within this ASU also require certain disclosures about stranded tax effects. The ASU became effective for the Company on January 1, 2019, at which time we adopted it. This ASU did not have a material impact on our consolidated financial statements.

In August 2018, the FASB issued two ASU’s as part of its disclosure framework project. The focus of this project is to improve the effectiveness of disclosures in the notes to the financial statements by facilitating clear communication of the information required by GAAP that is most important to users of an entity’s financial statements. Both of these ASU’s remove certain disclosure requirements and add or modify other requirements. The two ASU’s are as follows:

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ASU No. 2018-13, Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement – effective for the Company on January 1, 2020, although early adoption is permitted immediately. Additionally, companies are permitted to immediately adopt the removal or modifications of disclosures as provided in this ASU, and adopt the additional disclosures on the effective date of the ASU. Certain provisions of the ASU must be adopted retrospectively, while others must be adopted prospectively. The Company is still assessing when and how it will adopt this ASU, but does not expect there to be a material impact to the notes to the consolidated financial statements.

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ASU No. 2018-14, Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans – this ASU will impact certain 10-K disclosures and will be effective for the Company for its 2020 Annual Report on Form 10-K. Early adoption is permitted and must be applied on a retrospective basis. The Company is still assessing when it will adopt this ASU, but does not expect there to be a material impact to the notes to the consolidated financial statements.

Adopted

In August 2018, the FASB issued ASU No. 2018-15, Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, which requires implementation costs, in a hosting arrangement that is a service contract, to be capitalized consistent with the rules in ASC 350-40, Intangibles—Goodwill and Other—Internal-Use Software. Costs incurred during the application development stage are to be capitalized and expensed according to their nature, while costs incurred during the preliminary project and post-implementation stages are to be expensed. This ASU also contains guidance with regard to the amortization period, impairment and presentation within the financial statements. The ASU is required to be adopted by the Company during 2020, however early adoption is allowed in an interim period before then, and may be applied retrospectively or prospectively to applicable costs on the Company’s consolidated financial statements. The Company adopted this ASU prospectively during the fourth quarter of 2018, which began on October 1. The impact of this ASU is not material.

In August 2018, the SEC issued a final rule that amended certain of its disclosure requirements that have become redundant, duplicative or superseded in light of other SEC disclosure requirements, changes in U.S. GAAP, or other information that has become widely available. As part of the SEC’s overall effort to improve the effectiveness of financial reporting requirements, the amendments contained in the final rule were intended to facilitate the disclosure of information to investors and simplify compliance without significantly altering the total mix of information provided to investors. Certain amendments affect this Annual Report on Form 10-K, while others were reflected initially in our Quarterly Report on Form 10-Q filed on November 2, 2018. Specifically, the final rule changes to annual requirements which have been reflected in this Form 10-K include the elimination of the ratio of earnings to fixed charges schedule, as well as changes to the market price information and geographic data contained in Parts I and II of this Form 10-K. None of these changes have a significant impact to our Form 10-K.

In May 2014, the FASB issued ASU No. 2014-09, Revenue From Contracts With Customers. The new standard supersedes most current revenue recognition guidance and eliminates most industry-specific guidance. The ASU is based on the principle that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to fulfill a contract. Entities had the option of using either a full retrospective or a modified retrospective approach for the adoption of the new standard. Additional ASUs have since been issued which provide further guidance, examples and technical corrections for the implementation of ASU No. 2014-09. All related guidance has been codified into, and is now known as, ASC 606. The guidance was effective for, and was adopted by, the Company as of January 1, 2018 using the modified retrospective method, and has a material impact on the consolidated financial statements and their accompanying notes containing our 2018 information. A full description of each impact, as well as the new disclosures required by ASC 606, is discussed in Note 4 — Revenue.

In March 2017, the FASB issued ASU No. 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost, which requires entities to (1) disaggregate the current service-cost component from the other components of net benefit cost (the ‘other components’) and present it in the income statement with other current compensation costs for related employees and (2) present the other components elsewhere in the income statement and outside of income from operations if that subtotal is presented. In addition, the ASU requires entities to disclose the income statement lines that contain the other components if they are not presented or included in appropriately-described separate lines. The ASU became effective for the Company on January 1, 2018, and it has applied the standard retrospectively in this Annual Report on Form 10-K. As a result of adopting this ASU, the Company classified or reclassified net periodic pension and postretirement benefit credits totaling $280 million, $222 million and $203 million for the years ended December 31, 2018, 2017 and 2016, respectively, from salaries and benefits expense to other income, net, in the consolidated statements of comprehensive income.

In May 2017, the FASB issued ASU No. 2017-09, Stock Compensation - Scope of Modification Accounting, which provides guidance on which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting. The ASU requires that an entity should account for the effects of a modification unless the fair value (or calculated value or intrinsic value, if used), vesting conditions and classification (as equity or liability) of the modified award are all the same as for the original award immediately before the modification. The ASU became effective for the Company on January 1, 2018 and will be applied prospectively to any award modified on or after this date. There is no immediate impact to the accompanying consolidated financial statements, until such time as an award may be modified in 2019 or beyond.

In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows - Classification of Certain Cash Receipts and Cash Payments, which amends guidance on presentation and classification of eight specific cash flow issues with the objective of reducing diversity in practice. The ASU became effective for the Company on January 1, 2018 on a prospective basis. While there was no impact to the consolidated statement of cash flows for the year ended December 31, 2018, the Company will reflect the new guidance prospectively as applicable transactions occur.

Merger Acquisitions and Divestitures

12 Months Ended

Dec. 31, 2018

Business Combinations [Abstract]

Merger Acquisitions and Divestitures

Note 3 — Merger, Acquisitions and Divestitures

The following paragraphs describe significant transactions during the three year period ending December 31, 2018. There have been other less significant transactions during this time period which have not been discussed.

Merger

On January 4, 2016, pursuant to the Agreement and Plan of Merger, dated June 29, 2015, as amended on November 19, 2015, between Willis, Towers Watson, and Citadel Merger Sub, Inc., a wholly-owned subsidiary of Willis formed for the purpose of facilitating this transaction (‘Merger Sub’), Merger Sub merged with and into Towers Watson, with Towers Watson continuing as the surviving corporation and as a wholly-owned subsidiary of Willis.

Towers Watson was a leading global professional services firm operating throughout the world, dating back more than 100 years. The Merger allows the combined firm to go to market with complementary strategic product and services offerings.

At the effective time of the Merger (the ‘Effective Time’), each issued and outstanding share of Towers Watson common stock (the ‘Towers Watson shares’), was converted into the right to receive 2.6490 validly issued, fully paid and nonassessable ordinary shares of Willis (the ‘Willis ordinary shares’), $0.000115 nominal value per share, other than any Towers Watson shares owned by Towers Watson, Willis or Merger Sub at the Effective Time and the Towers Watson shares held by stockholders who are entitled to and who properly exercised dissenter’s rights under Delaware law.

The Merger was accounted for using the acquisition method of accounting, with Willis considered the accounting acquirer of Towers Watson.

The table below presents the final calculation of aggregate Merger consideration.

	January 4, 2016
Number of shares of Towers Watson common stock outstanding as of January 4, 2016	69 million
Exchange ratio		2.6490
Number of Willis Group Holdings shares issued (prior to reverse stock split)	184 million
Willis Group Holdings price per share on January 4, 2016	$	47.18
Fair value of 184 million Willis ordinary shares	$	8,686
Value of equity awards assumed		37
Aggregate Merger consideration	$	8,723

The Company acquired cash and cash equivalents of $476 million as a result of the Merger.

Acquisitions

Alston Gayler Acquisition

On December 21, 2018, the Company, through its majority-owned subsidiary, Miller, completed the transaction to acquire Alston Gayler, a U.K.-based insurance and reinsurance broker, for total consideration of $67 million. Cash consideration of $35 million was paid upon completion of the acquisition, with the remaining $32 million deferred consideration to be paid in equal installments on the first, second and third anniversaries of the date of acquisition.

The Company has preliminarily recognized $36 million of intangible assets, primarily arising from client relationships, and $24 million of goodwill. The purchase price allocation as of the acquisition date and our accounting for the related tax assets and liabilities is not yet complete.

Divestitures

Related Party Transaction - In the third quarter of 2017, the Company divested its Global Wealth Solutions business through a sale to an employee of the business. As part of that transaction, we financed a $50 million note payable from the employee to purchase the business. The note amortizes over 10 years, bears interest at a weighted-average rate of 3% and is guaranteed by $3 million in assets. Following the sale, employees of this business are no longer employees of the Company, and the purchasing employee is no longer considered a related party. The current and non-current portions of the note receivable are included in the tables found in Note 15 — Supplementary Information for Certain Balance Sheet Accounts to these consolidated financial statements as Other current assets and Other non-current assets.

2017 Cumulative Divestiture Impact - Including the divestiture of Global Wealth Solutions, we sold five businesses during the second half of 2017. For the year ended December 31, 2017, the total gain recognized related to business disposals was $13 million, which was recorded in Other income, net on the accompanying consolidated statements of comprehensive income. Results from these disposals prior to the sales represented $54 million of revenue and $13 million of operating income for the year ended December 31, 2017.

Revenue

12 Months Ended

Dec. 31, 2018

Revenue From Contract With Customer [Abstract]

Restructuring And Related Activities [Abstract]

Note 4 — Revenue

As of January 1, 2018, the Company adopted ASC 606. The adoption of this new guidance had a material impact to the amounts and classification of certain balances within our consolidated financial statements and disclosures in the accompanying notes.

We adopted ASC 606 using the modified retrospective approach, and elected to apply the following ‘practical expedients’ during adoption:

•

We elected to apply the new standard only to contracts that were not completed as of the transition date. This had the net effect of reducing revenue recognized under ASC 606 due to the change in method in our Health and Benefits broking business. See a further discussion and quantification for the annual results below.

•

We elected to reflect the aggregate effect of all modifications made to contracts prior to the transition date, January 1, 2018, rather than retrospectively restating the contracts for each of these modifications.

We recognized the cumulative effect of initially applying ASC 606 as an adjustment to the opening balance of retained earnings. The comparative periods included within this Annual Report on Form 10-K have not been restated and continue to be reported under the accounting standards in effect for those periods.

The cumulative effect of the changes made to our consolidated January 1, 2018 balance sheet for the adoption of ASC 606 were as follows:

Balance Sheet	Balance at December 31, 2017		Adjustments due to ASC 606				Balance at January 1, 2018
ASSETS
Accounts receivable, net	$	2,246	$	309		a	$	2,555
Prepaid and other current assets		430		89		b		519
Fixed assets, net		985		(83	)	c		902
Other non-current assets		447		39		c		486
LIABILITIES
Deferred revenue and accrued expenses		1,711		(74	)	d		1,637
Deferred tax liabilities		615		99		e		714
Provision for liabilities		558		12		f		570
EQUITY
Retained earnings		1,104		317		g		1,421

In accordance with the modified retrospective adoption requirements of ASC 606, the following disclosures represent the impact of adoption on our consolidated statement of comprehensive income, balance sheet and statement of cash flows:

	Year Ended December 31, 2018
Statement of Comprehensive Income	As Reported			Balances Without Adoption of ASC 606			Effect of Change
Revenue	$	8,513		$	8,613		$	(100	)	h
Costs of providing services
Salaries and benefits		5,123			5,098			25		i
Depreciation		208			235			(27	)	i
Income from operations		809			907			(98	)
INCOME FROM OPERATIONS BEFORE INCOME TAXES		851			949			(98	)
Provision for income taxes		(136	)		(154	)		18		j
NET INCOME		715			795			(80	)
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON		695			775			(80	)

EARNINGS PER SHARE
Basic earnings per share	$	5.29		$	5.90		$	(0.61	)
Diluted earnings per share	$	5.27		$	5.87		$	(0.60	)

	As of December 31, 2018
Balance Sheet	As Reported		Balances Without Adoption of ASC 606		Effect of Change
ASSETS
Accounts receivable, net	$	2,379	$	2,198	$	181		a
Prepaid and other current assets		404		302		102		b
Fixed assets, net		942		1,051		(109	)	c
Other non-current assets		467		419		48		c
LIABILITIES
Deferred revenue and accrued expenses		1,647		1,754		(107	)	d
Other current liabilities		864		863		1		e
Deferred tax liabilities		559		479		80		e
Provision for liabilities		540		529		11		f
EQUITY
Retained earnings		1,201		964		237		g

	Year Ended December 31, 2018
Statement of Cash Flows	As Reported			Balances Without Adoption of ASC 606			Effect of Change
Net cash from operating activities	$	1,288		$	1,338		$	(50	)	k
Capitalized software costs		(54	)		(104	)		50		k

Explanation of Changes

The adoption of ASC 606 had the following impacts to our balance sheets at January 1, 2018 and December 31, 2018:

Accounts receivable, net, now includes receivables that have been billed, not yet billed and short-term contract assets. This adjustment is the result of the cumulative adjustments to revenue that have not yet been collected from our customers, but are expected to be collected within the next twelve months. The most significant increases to this balance result from revenue acceleration under ASC 606 for Medicare and proportional treaty broking commissions.

Prepaid and other current assets include the impact of costs deferred in connection with our broking pre-placement activities. These costs are being deferred while the related pre-placement work is performed, and amortized as the related revenue is recognized, typically upon policy inception. Since the amortization period associated with these fulfillment costs is less than one year, these deferred costs have been classified as a current asset.

Prior to the adoption of ASC 606, costs that we deferred related to certain system implementation activities had been included in fixed assets, net. These costs, adjusted based on the guidance in ASC 606, have now been included in other non-current assets. Additionally we have included less significant impacts of adjustments to deferred tax assets and have classified non-current contract assets within non-current assets.

Deferred revenue has been adjusted primarily to reflect revenue acceleration in our Medicare broking business. Additional adjustments were included to accelerate the license component of certain software arrangements and to net deferred revenue with contract assets.

Other current liabilities, which include current taxes payable, and deferred tax liabilities, have been adjusted for the tax effects of the individual changes resulting from the adoption of ASC 606. The income tax expense was calculated based on the U.S. and foreign statutory rates applicable to adjustments made. Where applicable, a U.S. statutory rate of 21% was used.

Provision for liabilities has been adjusted for additional reserves for long-term post-placement obligations in our broking business.

Retained earnings has been adjusted for the net impact of the adoption of ASC 606. See the discussion of the significant pre-tax changes by revenue in the following section.

The following changes are now reflected in our consolidated statements of comprehensive income for the year ended December 31, 2018. Each description also includes a discussion of the impact to retained earnings as of the adoption date.

	Retained Earnings Increase/(Decrease) at January 1, 2018			Increase/(Decrease) for the Year Ended December 31, 2018
Revenue adjustments
Medicare broking	$	311		$	(38	)
Proportional treaty reinsurance broking		50			2
Health and benefits broking		—			(57	)
Other adjustments		28			(7	)
Total adjustments related to revenue		389			(100	)

Cost adjustments
System implementation activities		(46	)		6
Other cost adjustments		75			(8	)
Total adjustments related to costs		29			(2	)

Tax effect		(101	)		(18	)
Total net adjustments	$	317		$	(80	)

Revenue was adjusted for the following significant changes:

•

Medicare broking — The majority of revenue recognition for this offering, within our Individual Marketplace business, has moved from monthly ratable recognition over the policy period, to recognition upon placement of the policy. Consequently, the Company will now recognize approximately two-thirds of one calendar year of expected commissions during its fourth quarter of the preceding calendar year. The remainder of the revenue is recognized consistently with methods used prior to the adoption of ASC 606. Therefore, at the adoption date, we have reflected a $271 million pre-tax increase to retained earnings for the portion of the revenue that would otherwise have been recognized during our 2018 calendar year since our earnings process was largely completed during the fourth quarter of 2017. Additionally, we have reflected a $40 million pretax adjustment to increase retained earnings related to previously deferred contingent revenue from placements made prior to 2018 because the earnings process was complete under ASC 606. During the year ended December 31, 2018, the accounting for this revenue stream under ASC 606 represented a reduction of revenue from ASC 605, Revenue Recognition (‘ASC 605’) accounting methods of $38 million.

•

Proportional treaty reinsurance broking — The revenue recognition for proportional treaty reinsurance broking commissions, within our Investment, Risk and Reinsurance segment, has moved from recognition upon the receipt of the monthly or quarterly treaty statements from the ceding insurance carriers, to the recognition of an estimate of expected commissions upon the policy effective date. Since the majority of revenue recognized historically based on these monthly or quarterly statements was received over a two-year period, we reflected a $50 million pretax increase to retained earnings at the adoption date for the portion of revenue that would otherwise have been recognized during our 2018 calendar year related to policies effective in 2017 or prior years. For the year ended December 31, 2018, this accounting change resulted in a revenue increase of $2 million related to this adjustment.

•

Health and benefits broking — Revenue for certain Health and Benefits broking arrangements, in our Human Capital and Benefits segment, will now be recognized evenly over the year to reflect the nature of the ongoing obligations to our customers as well as receipt of the monthly commissions. These contracts are monthly or annual in nature, and are considered complete as of the transition date. Therefore, no retained earnings adjustment is required. The total effect to revenue as a result of this accounting change for the year ended December 31, 2018 was a decrease of $57 million.

•

Other adjustments — Certain other revenue changes with individually less significant adjustments were made to retained earnings as of the adoption date totaling a net $28 million. The cumulative change to revenue for the year ended December 31, 2018 for other revenue streams not discussed above resulting from the ASC 606 adoption was a decrease of $7 million.

Salaries and benefits and depreciation expense have been impacted by the guidance for deferred costs. Our accounting for these deferred costs has changed for certain revenue streams with system implementation activities, and other types of arrangements with associated costs, that now meet the criteria for cost deferral under ASC 606:

•

System implementation activities — For those portions of the business that previously deferred costs, the length of time over which we amortize those costs will extend to a longer estimated contract term. For 2017 and prior years, these costs were amortized over a typical period of 3-5 years in accordance with the initial stated terms of the customer agreements. Additionally, the composition of deferred costs has been adjusted to reflect the guidance in ASC 606. A reduction adjustment to retained earnings of $46 million was recorded on the adoption date to reflect these changes. Further, the amortization of the costs are no longer classified as depreciation expense, but rather included in salaries and benefits. These adjustments resulted in an increase in expense of $6 million for the year ended December 31, 2018.

•

Other cost adjustments — This guidance now applies to our broking arrangements and certain consulting engagements. While the costs deferred for our broking arrangements will typically be amortized within one year, costs now deferred related to certain consulting arrangements will be amortized over a longer term. We have increased pre-tax retained earnings by $75 million, primarily to reflect the total changes to contract costs as of the adoption date. For the year ended December 31, 2018, these changes resulted in a decrease in expense of $8 million.

The provision for income taxes for the year ended December 31, 2018 was $18 million lower than our provision on an ASC 605 basis. The income tax expense was calculated based on the U.S. and foreign statutory rates applicable to adjustments made. Where applicable, a U.S. statutory rate of 21% was used. There was a $101 million net tax reduction to retained earnings upon adoption of ASC 606.

The following changes are now reflected in our consolidated statement of cash flows for the year ended December 31, 2018.

As part of the changes in accounting for deferred costs, amounts capitalized relating to system implementation activities are now classified as operating cash flows. Prior to 2018, those costs capitalized under previous guidance were included in Capitalized software costs as an investing cash outflow.

Disaggregation of Revenue

The Company reports revenue by segment in Note 5 — Segment Information. The following table presents revenue by service offering and segment, as well as a reconciliation to total revenue for the year ended December 31, 2018. Along with reimbursable expenses and other, total revenue by service offering represents our revenue from customer contracts. See Note 5 — Segment Information for further information.

	Year ended December 31, 2018
	HCB		CRB		IRR		BDA		Corporate ⁽ⁱ⁾		Total
Broking	$	266	$	2,578	$	905	$	272	$	—	$	4,021
Consulting		2,224		163		430		—		13		2,830
Outsourced administration		484		65		—		486		—		1,035
Other		235		9		185		—		4		433
Total revenue by service offering		3,209		2,815		1,520		758		17		8,319
Reimbursable expenses and other ⁽ⁱ⁾		62		—		8		7		17		94
Total revenue from customer contracts	$	3,271	$	2,815	$	1,528	$	765	$	34	$	8,413
Interest and other income ⁽ⁱⁱ⁾		24		37		36		—		3		100
Total revenue	$	3,295	$	2,852	$	1,564	$	765	$	37	$	8,513

_________

(i)	Reimbursable expenses and other, as well as Corporate revenue, are excluded from segment revenue, but included in total revenue on the consolidated statements of comprehensive income.

(ii)	Interest and other income is included in segment revenue and total revenue, however it has been presented separately in the above tables because it does not arise directly from contracts with customers.

Individual revenue streams aggregating to 5% of total revenue for the year ended December 31, 2018 have been included within the Other line in the table above.

The following table presents revenue by the geography where our work was performed for the year ended December 31, 2018. The reconciliation to total revenue on our consolidated statements of comprehensive income and to segment revenue is shown in the table above.

	Year ended December 31, 2018
	HCB		CRB		IRR		BDA		Corporate		Total
North America	$	1,849	$	1,044	$	416	$	758	$	16	$	4,083
Great Britain		481		648		732		—		—		1,861
Western Europe		562		631		218		—		1		1,412
International		317		492		154		—		—		963
Total revenue by geography	$	3,209	$	2,815	$	1,520	$	758	$	17	$	8,319

Contract Balances

The Company reports accounts receivable, net on the consolidated balance sheet, which includes billed and unbilled receivables and current contract assets. In addition to accounts receivable, net, the Company had the following non-current contract assets and deferred revenue balances at December 31, 2018 and January 1, 2018:

	December 31, 2018		January 1, 2018
Billed receivables, net of allowance for doubtful accounts of $40 million and $45 million	$	1,702	$	1,933
Unbilled receivables		356		276
Current contract assets		321		346
Accounts receivable, net	$	2,379	$	2,555
Non-current accounts receivable, net	$	20	$	33
Non-current contract assets	$	3	$	5
Deferred revenue	$	448	$	463

The Company receives payments from customers based on billing schedules or terms as written in our contracts. Those balances denoted as contract assets relate to situations where we have completed some or all performance under the contract, however our right to consideration is conditional. Contract assets result most materially in our Medicare broking and proportional treaty broking businesses. Billed and unbilled receivables are recorded when the right to consideration becomes unconditional. Deferred revenue relates to payments received in advance of performance under the contract, and is recognized as revenue as (or when) we perform under the contract.

Accounts receivable are stated at estimated net realizable values. The following table presents the changes in our allowance for doubtful accounts for the years ended December 31, 2018, 2017 and 2016.

	December 31, 2018			December 31, 2017			December 31, 2016
Balance at beginning of year	$	45		$	40		$	22
Additions charged to costs and expenses		9			17			36
Charges to other accounts - acquisitions		—			—			8
Deductions/other movements		(15	)		(9	)		(27	)
Foreign exchange		1			(3	)		1
Balance at end of year	$	40		$	45		$	40

During the year ended December 31, 2018, revenue of approximately $389 million was recognized that was reflected as deferred revenue at January 1, 2018. There were no other primary drivers for the changes in contract assets and liabilities from January 1, 2018 to December 31, 2018 besides the recognition of revenue and receipts of cash.

During the year ended December 31, 2018, the Company recognized no material revenue related to performance obligations satisfied in a prior period.

Performance Obligations

The Company has contracts for which performance obligations have not been satisfied as of December 31, 2018 or have been partially satisfied as of December 31, 2018. The following table shows the expected timing for the satisfaction of the remaining performance obligations. This table does not include contract renewals nor variable consideration, which was excluded from the transaction prices in accordance with the guidance on constraining estimates of variable consideration.

In addition, the Company has elected not to disclose the remaining performance obligations when one or both of the following circumstances apply:

•

Performance obligations which are part of a contract that has an original expected duration of less than one year, and

•

Performance obligations satisfied in accordance with ASC 606-10-55-18 (‘right to invoice’).

		2019				2020				2021 onward				Total
Revenue expected to be recognized on contracts as of December 31, 2018		$	441			$	357			$	466			$	1,264

Since most of the Company’s contracts are cancellable with less than one year’s notice, and have no substantive penalty for cancellation, the majority of the Company’s remaining performance obligations as of December 31, 2018 has been excluded from the table above.

Costs to obtain or fulfill a contract

The Company incurs costs to obtain or fulfill contracts which it would not incur if a contract with a customer was not executed.

The following table shows the categories of costs that are capitalized and deferred over the expected life of a contract.

	Costs to fulfill
Balance at January 1, 2018	$	126
New capitalized costs		465
Amortization		(442	)
Impairments		—
Foreign currency translation		(1	)
Balance at December 31, 2018	$	148

Segment Information

12 Months Ended

Dec. 31, 2018

Segment Reporting [Abstract]

Segment Information

Note 5 — Segment Information

Willis Towers Watson has four reportable operating segments or business areas:

•

Human Capital and Benefits (‘HCB’)

•

Corporate Risk and Broking (‘CRB’)

•

Investment, Risk and Reinsurance (‘IRR’)

•

Benefits Delivery and Administration (‘BDA’)

Willis Towers Watson’s chief operating decision maker is its chief executive officer. We determined that the operational data used by the chief operating decision maker is at the segment level. Management bases strategic goals and decisions on these segments and the data presented below is used to assess the adequacy of strategic decisions and the method of achieving these strategies and related financial results. Management evaluates the performance of its segments and allocates resources to them based on net operating income on a pre-bonus, pre-tax basis.

The Company experiences seasonal fluctuations of its revenue. Revenue is typically higher during the Company’s first and fourth quarters due to the timing of broking-related activities, and although the mix of quarterly income changed as a result of the adoption of ASC 606, we expect our revenue to remain highest in our first and fourth quarters.

Beginning in 2018, we made certain changes that affect our segment results that are not material. These changes include the following:

•

To better align our business within our segments, we (1) moved portions of our Insurance, Consulting and Technology business from IRR to CRB; (2) moved certain resources that support our outsourced administration offerings from HCB to BDA; and (3) moved our CEEMEA-based strategy study business from our Health and Benefits business in HCB to CRB.

•

As part of the continued integration of our businesses, we have applied our 2018 corporate expense allocation methodology to our 2017 and 2016 segment results in order to standardize our methodologies and allocate those expenses for period over period comparatives. Such methodology updates include (1) an increased allocation for Gras Savoye as it no longer benefits as a new acquisition; (2) adjustments relating to changes in segment and total headcount; and (3) the addition of certain allocable direct expenses, which lowers the corporate expense allocation.

In connection with our segment realignment, we reassigned a proportional amount of the carrying value of goodwill between the CRB and IRR segments. See Note 9 — Goodwill and Other Intangible Assets for further information.

Previously during the year ended December 31, 2017, the Company made changes to our segment results which standardized the allocation of corporate expenses directly attributable to business segments, reassigned Max Matthiessen to IRR and Fine Art, Jewellery & Specie to CRB to better align with their specializations, and revised the presentation of certain costs impacting fixed assets and internally-developed software which arose from the purchase accounting for the Merger.

The prior period comparatives reflected in the tables below have been retroactively adjusted to reflect our current segment presentation.

Under the segment structure and for internal and segment reporting, Willis Towers Watson segment revenue includes commissions and fees, interest and other income. U.S. GAAP revenue includes amounts that were directly incurred on behalf of our clients and reimbursed by them (reimbursable expenses), which are removed from segment revenue. Segment operating income excludes certain costs, including (i) amortization of intangibles; (ii) restructuring costs; (iii) certain transaction and integration expenses; (iv) certain litigation provisions; (v) significant pension settlement and curtailment gains or losses; and (vi) to the extent that the actual expense based upon which allocations are made differs from the forecast/budget amount, a reconciling item will be created between internally-allocated expenses and the actual expenses that we report for U.S. GAAP purposes.

During 2016, segment revenue and operating income both include revenue that was deferred by Towers Watson at the time of the Merger, and eliminated due to purchase accounting. The impact of the elimination from purchase accounting (which is the reduction to 2016 consolidated revenue and operating income) has been included in the reconciliation to our consolidated results in order to provide the actual revenue that the segments would have recognized on an unadjusted basis.

The following table presents segment revenue and segment operating income for our reportable segments for the years ended December 31, 2018, 2017 and 2016.

	Segment revenue						Segment operating income
	Years ended December 31						Years ended December 31
	2018		2017		2016		2018		2017		2016
HCB	$	3,233	$	3,176	$	3,100	$	789	$	774	$	722
CRB		2,852		2,709		2,608		528		483		458
IRR		1,556		1,474		1,473		384		329		346
BDA		758		734		660		144		153		120
Total	$	8,399	$	8,093	$	7,841	$	1,845	$	1,739	$	1,646

The following table presents reconciliations of the information reported by segment to the Company’s consolidated amounts reported for the years ended December 31, 2018, 2017 and 2016.

	Years ended December 31,
	2018			2017			2016
Revenue:
Total segment revenue	$	8,399		$	8,093		$	7,841
Fair value adjustment to deferred revenue		—			—			(58	)
Reimbursable expenses and other		114			109			104
Revenue	$	8,513		$	8,202		$	7,887

Total segment operating income	$	1,845		$	1,739		$	1,646
Fair value adjustment for deferred revenue		—			—			(58	)
Amortization		(534	)		(581	)		(591	)
Restructuring costs		—			(132	)		(193	)
Transaction and integration expenses ⁽ⁱ⁾		(202	)		(269	)		(177	)
Provisions for significant litigation		—			(11	)		(50	)
Unallocated, net ⁽ⁱⁱ⁾		(300	)		(230	)		(229	)
Income from operations		809			516			348
Interest expense		(208	)		(188	)		(184	)
Other income, net		250			164			178
Income from operations before income taxes	$	851		$	492		$	342

(i)	Includes transaction and integration expenses related to the Merger and the acquisition of Gras Savoye.

(ii)	Includes certain costs, primarily related to corporate functions which are not directly related to the segments, and certain differences between budgeted expenses determined at the beginning of the year and actual expenses that we report for U.S. GAAP purposes.

The Company does not currently provide asset information by reportable segment as it does not routinely evaluate the total asset position by segment.

None of the Company’s customers represented a significant amount of the Company’s consolidated revenue for the years ended December 31, 2018, 2017 and 2016.

Below are our revenue and long-lived assets for Ireland, our country of domicile, countries with significant concentrations, and all other foreign countries for each of the years ended December 31, 2018, 2017 and 2016:

	Revenue						Long-Lived Assets ⁽ⁱ⁾
	2018		2017		2016		2018		2017		2016
Ireland	$	138	$	107	$	92	$	78	$	127	$	114

United States		3,970		3,821		3,395		11,068		9,988		11,400
United Kingdom		1,926		1,815		2,236		2,349		3,173		2,431
Rest of World		2,479		2,459		2,164		2,411		3,263		2,466
Total Foreign Countries		8,375		8,095		7,795		15,828		16,424		16,297
	$	8,513	$	8,202	$	7,887	$	15,906	$	16,551	$	16,411

(i)	Long-lived assets do not include deferred tax assets.

Restructuring Costs

12 Months Ended

Dec. 31, 2018

Restructuring Costs

Note 6 — Restructuring Costs

The Company had two major elements of the restructuring costs included in its consolidated financial statements, which were the Operational Improvement Program and the Business Restructure Program. Costs for each program were fully accrued and completed by the end of 2017 and 2016, respectively. No additional costs for either program were incurred during 2018.

Operational Improvement Program - In April 2014, Legacy Willis announced a multi-year operational improvement program designed to strengthen its client service capabilities and to deliver future cost savings. The main elements of the program included: moving more than 3,500 support roles from higher cost locations to facilities in lower cost locations; net workforce reductions in support positions; lease consolidation in real estate; and information technology systems simplification and rationalization.

The Company recognized restructuring costs of $134 million and $145 million for the years ended December 31, 2017 and 2016, respectively, related to the Operational Improvement Program. The Company spent a cumulative amount of $441 million on restructuring costs for this program.

Business Restructure Program - In the second quarter of 2016, we began planning targeted staffing reductions in certain portions of the business due to a reduction in business demand or change in business focus (hereinafter referred to as the Business Restructure Program). The main element of the program included workforce reductions, and was completed in 2016, however, cash payments pertaining to the program were made primarily in 2017. During the year ended December 31, 2017, the Company recognized a $2 million reversal of expense related to an estimate of previously incurred termination benefits. The Company recognized restructuring costs of $48 million for the year ended December 31, 2016.

An analysis of total restructuring costs recognized in the consolidated statements of comprehensive income, with costs by segment, and costs attributable to corporate functions, for the years ended December 31, 2017 and 2016 is as follows:

	HCB		CRB		IRR		BDA		Corporate		Total
Year ended December 31, 2017
Termination benefits	$	—	$	25	$	4	$	—	$	17	$	46
Professional services and other ⁽ⁱ⁾		3		63		6		—		14		86
Total	$	3	$	88	$	10	$	—	$	31	$	132

Year ended December 31, 2016
Termination benefits	$	33	$	26	$	6	$	1	$	2	$	68
Professional services and other ⁽ⁱ⁾		4		81		4		—		36		125
Total	$	37	$	107	$	10	$	1	$	38	$	193

(i)	Other includes salary and benefits, premises, and other expenses incurred to support the ongoing management and facilitation of the programs.

An analysis of the total cumulative restructuring costs recognized for the Operational Improvement Program from its commencement to December 31, 2017 by segment is as follows:

	HCB		CRB		IRR		BDA		Corporate		Total
2014
Termination benefits	$	—	$	15	$	1	$	—	$	—	$	16
Professional services and other ⁽ⁱ⁾		—		3		—		—		17		20
2015
Termination benefits	$	2	$	24	$	7	$	—	$	3	$	36
Professional services and other ⁽ⁱ⁾		1		57		2		—		30		90
2016
Termination benefits	$	1	$	18	$	3	$	—	$	1	$	23
Professional services and other ⁽ⁱ⁾		1		81		4		—		36		122
2017
Termination benefits	$	—	$	25	$	4	$	—	$	19	$	48
Professional services and other ⁽ⁱ⁾		3		63		6		—		14		86
Total
Termination benefits	$	3	$	82	$	15	$	—	$	23	$	123
Professional services and other ⁽ⁱ⁾		5		204		12		—		97		318
Total	$	8	$	286	$	27	$	—	$	120	$	441

(i)	Other includes salary and benefits, premises, and other expenses incurred to support the ongoing management and facilitation of the program.

The changes in the Company’s liability under the Operational Improvement Program from its commencement to December 31, 2018, are as follows:

	Termination Benefits			Professional Services and Other			Total
Balance at January 1, 2014	$	—		$	—		$	—
Charges incurred		16			20			36
Cash payments		(11	)		(14	)		(25	)
Balance at December 31, 2014		5			6			11
Charges incurred		36			90			126
Cash payments		(26	)		(85	)		(111	)
Balance at December 31, 2015		15			11			26
Charges incurred		23			122			145
Cash payments		(31	)		(115	)		(146	)
Balance at December 31, 2016		7			18			25
Charges incurred		48			86			134
Cash payments		(41	)		(97	)		(138	)
Balance at December 31, 2017		14			7			21
Cash payments		(12	)		(6	)		(18	)
Balance at December 31, 2018	$	2		$	1		$	3

Restructuring costs related to the Business Restructuring Program for the year ended December 31, 2016 by segment are as follows:

	HCB		CRB		IRR		BDA		Corporate		Total
	(in millions)
2016
Termination benefits	$	32	$	8	$	3	$	1	$	1	$	45
Professional services and other ⁽ⁱ⁾		3		—		—		—		—		3
Total	$	35	$	8	$	3	$	1	$	1	$	48

(i)	Other includes salary and benefits, premises, and other expenses incurred to support the ongoing management and facilitation of the program.

The changes in the Company’s liability under the Business Restructure Program from its commencement to December 31, 2018, are as follows:

	Termination Benefits			Professional Services and Other			Total
Balance at January 1, 2016	$	—		$	—		$	—
Charges incurred		45			3			48
Cash payments		(19	)		(3	)		(22	)
Balance at December 31, 2016		26			—			26
Adjustment to prior charges incurred		(2	)		—			(2	)
Cash payments		(23	)		—			(23	)
Balance at December 31, 2017		1			—			1
Cash payments		(1	)		—			(1	)
Balance at December 31, 2018	$	—		$	—		$	—

Income Taxes

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Income Taxes

Note 7 — Income Taxes

Impact of U.S. Tax Reform

On December 22, 2017, the U.S. government enacted comprehensive tax legislation, commonly referred to as ‘U.S. Tax Reform’. U.S. Tax Reform makes broad and complex changes to the U.S. tax code, including, but not limited to: (1) requiring a one-time transition tax on certain unremitted earnings of foreign subsidiaries that may be payable over eight years; (2) bonus depreciation that will allow for full expensing of qualified property; (3) reduction of the federal corporate tax rate from 35% to 21%; (4) a new provision designed to tax global intangible low-taxed income (‘GILTI’), which allows for the possibility of using foreign tax credits (‘FTCs’) and a deduction of up to 50% to offset the income tax liability (subject to some limitations); (5) a new limitation on deductible interest expense; (6) limitations on the deductibility of certain executive compensation; (7) limitations on the use of FTCs to reduce the U.S. income tax liability; (8) the creation of the base erosion anti-abuse tax (‘BEAT’), a new minimum tax; and (9) a general elimination of U.S. federal income taxes on dividends from foreign subsidiaries.

Also on December 22, 2017, the SEC staff issued Staff Accounting Bulletin No. 118 (‘SAB 118’), which provided guidance on accounting for the tax effects of the U.S. Tax Reform. SAB 118 provided a measurement period that should not extend beyond one year from the U.S. Tax Reform enactment date for companies to complete the accounting under ASC 740, Income Taxes (‘ASC 740’). In accordance with SAB 118, a company was required to reflect the income tax effects of those aspects of U.S. Tax Reform for which the accounting under ASC 740 was complete. Adjustments to incomplete and unknown amounts were required to be recorded and disclosed during the measurement period. To the extent that a company’s accounting for certain income tax effects of U.S. Tax Reform was incomplete but it was able to determine a reasonable estimate, a provisional estimate in the financial statements was required to be recorded. If a company was unable to determine a provisional estimate, it was required to continue to apply ASC 740 on the basis of the provisions of the tax laws that were in effect immediately before the enactment of U.S. Tax Reform.

While the measurement period under SAB 118 is now closed, the Company may in future periods need to further refine its U.S. federal and state calculations related to U.S. Tax Reform as the taxing authorities provide additional guidance and clarification. However, as of December 31, 2018, the Company's accounting for U.S. Tax Reform is complete based on its interpretation of the guidance issued as of the balance sheet date.

As such, the Company has revised and finalized the provisional adjustments for the following items:

Reduction of the federal corporate tax rate – Beginning January 1, 2018, the Company’s U.S. income is taxed at a 21% federal corporate tax rate. Under ASC 740, deferred tax assets or liabilities must be recalculated as of the enactment date using current tax laws and rates expected to be in effect when the deferred tax items reverse in future periods, which is 21%. Consequently, the Company recorded a provisional decrease in its net deferred tax liabilities of $208 million, with a corresponding deferred income tax benefit of $208 million during the year ended December 31, 2017. On October 12, 2018, the Company filed its 2017 U.S. federal corporate income tax return. After refining our analysis of those items directly related to U.S. Tax Reform, the Company recorded additional deferred tax benefit of approximately $8 million related to deferred tax items that are now subject to tax at 21%. The effect of the measurement period adjustment on the 2018 effective tax rate is approximately 1%.

One-time transition tax – The one-time transition tax is based on the Company’s total post-1986 earnings and profits (‘E&P’) that it previously deferred from U.S. income taxes. At December 31, 2017, the Company recorded a provisional amount for the one-time transition tax liability for our foreign subsidiaries owned by U.S. corporate shareholders, resulting in an increase in U.S. Federal income tax expense of $70 million and state income tax expense of $2 million. This transition tax liability was recorded as a long-term liability in the 2017 financial statements. Subsequent to the December 31, 2017 reporting period, the Internal Revenue Service (‘IRS’) clarified the application of the ‘with’ and ‘without’ approach for calculating the transition tax liability in determining the amount payable over eight years. Based on this guidance the Company revised its provisional estimate for the U.S. federal transition tax liability in the first quarter of 2018, which was reduced by $64 million due to the utilization of interest loss carryforwards resulting from the transition tax income inclusion. This reduction has no impact on the 2018 effective tax rate. Additionally, on the basis of revised E&P computations that were completed during the year ended December 31, 2018, we recognized an additional increase to income tax expense of $8 million, which was recorded in current income tax payable. This has an approximate 1% impact on the Company’s 2018 effective tax rate. The tax expense recorded includes the final measurement period adjustment related to the Company’s November 30, 2018 foreign subsidiaries. While the measurement period under SAB 118 is now closed, we may in future periods need to further refine the U.S. federal and state transition tax calculations of the November 30, 2018 foreign subsidiaries as the taxing authorities provide additional guidance and clarification.

Indefinite reinvestment assertion – Beginning in 2018, U.S. Tax Reform provides a 100% deduction for dividends received from 10-percent owned foreign corporations by U.S. corporate shareholders, subject to a one-year holding period. Although dividend income is now exempt from U.S. federal tax for U.S. corporate shareholders, companies must still account for the tax consequences of outside basis differences and other tax impacts of their investments in non-U.S. subsidiaries. At December 31, 2017, we analyzed our global working capital and cash requirements and the potential tax liabilities attributable to a repatriation and determined we might repatriate up to $219 million which was previously deemed indefinitely reinvested. For those investments from which we were able to make a reasonable estimate of the tax effects of such repatriation, we recorded a provisional estimate for foreign withholding and state income taxes of $1 million. In addition, we re-measured the existing deferred tax liability accrued on certain acquired Towers Watson subsidiaries and released the associated deferred tax liability. This resulted in an income tax benefit of $76 million as these foreign earnings were subject to the one-time transition tax. These estimates are now considered final and no further adjustments have been made in the year ended December 31, 2018 as a result of U.S. Tax Reform.

Bonus Depreciation – The Company completed its determination of all capital expenditures that qualify for immediate expensing. For the year ended December 31, 2017, the Company recorded a provisional deduction of $40 million based on its current intent to fully expense all qualifying expenditures. This resulted in an increase of approximately $14 million to the Company's U.S. federal current income taxes receivable and a corresponding increase in its net deferred tax liabilities of approximately $14 million. However, as a result of further analysis on assets placed in service after September 27, 2017, the Company concluded its tax deduction to be $8 million. The tax benefit was reflected on the Company’s 2017 U.S. federal corporate income tax return filed on October 12, 2018. The effect of the measurement-period adjustment on the 2018 effective tax rate is included in the reduction of the federal corporate tax rate above.

Executive compensation – Starting with compensation paid in 2018, Section 162(m) will limit the Company from deducting compensation, including performance-based compensation, in excess of $1 million paid to anyone who, starting in 2018, serves as the Chief Executive Officer or Chief Financial Officer, or who is among the three most highly compensated executive officers. The only exception to this rule is for compensation that is paid pursuant to a binding contract in effect on November 2, 2017 that would have otherwise been deductible under the prior Section 162(m) rules. Accordingly, any compensation paid in the future pursuant to new compensation arrangements entered into after November 2, 2017, even if performance-based, will count towards the $1 million deduction limit if paid to a covered executive. The Company recorded a provisional income tax expense of $8 million relating to our compensation plans not qualifying as a binding contract exception. During the fourth quarter the Company finalized its analysis and review of the executive compensation plans and IRS guidance released throughout the year. The Company has concluded that the reviewed plans are not subject to future limitation under the binding contract exception and grandfathering rules. This resulted in the re-establishment of the deferred tax asset through the recording of an income tax benefit of $8 million. The effect of the measurement period adjustment on the 2018 effective tax rate is approximately 1%.

GILTI – U.S. Tax Reform creates a new requirement that certain income (i.e., GILTI) earned by controlled foreign corporations (‘CFCs’) must be included currently in the gross income of the CFCs’ U.S. shareholders. GILTI is the excess of the shareholder’s ‘net CFC tested income’ over the net deemed tangible income return, which is currently defined as the excess of (1) 10 percent of the aggregate of the U.S. shareholder’s pro rata share of the qualified business asset investment of each CFC with respect to which it is a U.S. shareholder over (2) the amount of certain interest expense taken into account in the determination of net CFC-tested income. Under U.S. GAAP, the Company is allowed to make an accounting policy choice of either (1) treating taxes due on future U.S. inclusions in taxable income related to GILTI as a current-period expense when incurred (the ‘period cost method’) or (2) factoring such amounts into a company’s measurement of its deferred taxes (the ‘deferred method’). The Company has concluded it is treating the taxes due on U.S. inclusions in taxable income related to GILTI as a current-period expense when incurred (the ‘period cost method’). The estimated tax impact of GILTI, net of available foreign tax credits, is approximately $15 million at December 31, 2018.

Valuation allowances – The Company has concluded there have been no changes to valuation allowances as a result of U.S. Tax Reform.

Provision for income taxes

An analysis of income from operations before income taxes by taxing jurisdiction is shown below:

	Years ended December 31,
	2018			2017			2016
Ireland	$	(16	)	$	(23	)	$	(27	)
U.S.		(101	)		(198	)		(311	)
U.K.		182			31			123
Other jurisdictions		786			682			557
Total	$	851		$	492		$	342

The components of the (provision for)/benefit from income taxes include:

	Years ended December 31,
	2018			2017			2016
Current tax expense:
U.S. federal taxes	$	(98	)	$	(65	)	$	(35	)
U.S. state and local taxes		(25	)		(7	)		(14	)
U.K. corporation tax		(16	)		(14	)		(28	)
Other jurisdictions		(112	)		(99	)		(71	)
Total current tax expense		(251	)		(185	)		(148	)
Deferred tax benefit:
U.S. federal taxes		79			268			214
U.S. state and local taxes		12			(6	)		5
U.K. corporation tax		(6	)		9			(10	)
Other jurisdictions		30			14			35
Total deferred tax benefit		115			285			244
Total (provision for)/benefit from income taxes	$	(136	)	$	100		$	96

Included in the 2018 U.S. state and local tax expense is an approximate $25 million deferred tax benefit related to a valuation allowance release on certain state deferred tax assets offset with the write-off of certain state net operating losses that are no longer realizable.

Effective tax rate reconciliation

The reported (provision for)/benefit from income taxes differs from the amounts that would have resulted had the reported income before income taxes been taxed at the U.S. federal statutory rate. The principal reasons for the differences between the amounts provided and those that would have resulted from the application of the U.S. federal statutory tax rate are as follows:

	Years ended December 31,
	2018			2017			2016
INCOME FROM OPERATIONS BEFORE INCOME TAXES	$	851		$	492		$	342
U.S. federal statutory income tax rate		21	%		35	%		35	%
Income tax expense at U.S. federal tax rate		(179	)		(172	)		(120	)
Adjustments to derive effective tax rate:
Non-deductible expenses and dividends		(44	)		(68	)		(15	)
Non-deductible acquisition costs		(2	)		(11	)		(1	)
Disposal of non-deductible goodwill		1			(11	)		(2	)
Impact of change in rate on deferred tax balances		7			—			15
Effect of foreign exchange and other differences		1			(3	)		(6	)
Non-deductible Venezuelan foreign exchange loss		—			(2	)		(4	)
Changes in valuation allowances		80			(13	)		74
Net tax effect of intra-group items		99			97			98
Tax differentials of non-U.S. jurisdictions		(2	)		69			80
Tax differentials of U.S. state taxes and local taxes		(77	)		6			(14	)
Global Intangible Low-Taxed Income (GILTI)		(15	)		—			—
Impact of U.S. Tax Reform		—			204			—
Other items, net		(5	)		4			(9	)
(Provision for)/benefit from income taxes	$	(136	)	$	100		$	96

Included in the changes in valuation allowance for 2018, the Company recorded a deferred income tax benefit for approximately $71 million related to the valuation allowance release of certain state deferred tax assets.

In 2017, in connection with our initial analysis of U.S. Tax Reform, the Company recorded a provisional net tax benefit of $204 million, which consisted of a net benefit of $208 million due to the reduction of the federal corporate tax rate and re-measurement of our net U.S. deferred tax liabilities primarily related to acquisition-based intangibles, and a $76 million benefit related to the release of a deferred tax liability we had previously recorded on the accumulated earnings of certain Towers Watson subsidiaries. These net benefit items were offset by provisional expenses of $8 million recognized as a write-off of a deferred tax asset the Company had previously recorded on executive compensation as well as the U.S. federal and state income tax expense of $72 million associated with the one-time transition tax on foreign earnings of our subsidiaries.

Willis Towers Watson plc is a non-trading holding company tax resident in Ireland where it is taxed at the statutory rate of 25%. In 2018, the provision for income tax on operations has been reconciled above to the U.S. federal statutory tax rate of 21% due to significant operations in the U.S. The prior year effective tax rates have not been restated to reflect a U.S. federal statutory tax rate of 21%.

Deferred income taxes

Deferred income tax assets and liabilities reflect the effect of temporary differences between the assets and liabilities recognized for financial reporting purposes and the amounts recognized for income tax purposes. We recognize deferred tax assets if it is more likely than not that a benefit will be realized.

Deferred income tax assets and liabilities included in the consolidated balance sheets at December 31, 2018 and 2017 are comprised of the following:

	December 31,
	2018			2017
Deferred tax assets:
Accrued expenses not currently deductible	$	177		$	131
Net operating losses		91			145
Capital loss carryforwards		30			28
Accrued retirement benefits		285			339
Deferred compensation		82			69
Stock options		22			24
Financial derivative transactions		1			18
Gross deferred tax assets		688			754
Less: valuation allowance		(81	)		(162	)
Net deferred tax assets	$	607		$	592
Deferred tax liabilities:
Cost of intangible assets, net of related amortization	$	825		$	929
Cost of tangible assets, net of related depreciation		37			56
Prepaid retirement benefits		101			114
Accrued revenue not currently taxable		144			62
Deferred tax liabilities	$	1,107		$	1,161
Net deferred tax liabilities	$	500		$	569

During December 2017, the Company re-measured its U.S. deferred tax assets and liabilities as a result of U.S. Tax Reform to the newly enacted federal tax rate, which is 21%. The net deferred income tax assets are included in other non-current assets and the net deferred tax liabilities are included in deferred tax liabilities in our consolidated balance sheets.

	December 31,
	2018		2017
Balance sheet classifications:
Other non-current assets	$	59	$	46
Deferred tax liabilities		559		615
Net deferred tax liability	$	500	$	569

At December 31, 2018, we had U.S. federal and non-U.S. net operating loss carryforwards amounting to $288 million of which $239 million can be indefinitely carried forward under local statutes. The remaining $49 million of net operating loss carryforwards will expire, if unused, in varying amounts from 2019 through 2038. In addition, we had U.S. state net operating loss carryforwards of $515 million, which will expire in varying amounts from 2019 to 2038.

Management believes, based on the evaluation of positive and negative evidence, including the future reversal of existing taxable temporary differences, it is more likely than not that the Company will realize the benefits of net deferred tax assets of $607 million, net of the valuation allowance. During 2018, the Company decreased its valuation allowance by $81 million primarily related to the completion of an internal U.S. restructuring. The U.S. restructuring provided a source of positive evidence and enabled the Company to release valuation allowance on certain state deferred tax assets now considered realizable. In addition, the Company reassessed certain state net operating losses and determined these losses and related valuation allowance would never be realized. During 2017, the Company increased its valuation allowance by $28 million primarily due to state net operating losses.

At December 31, 2018 and 2017, the Company had valuation allowances of $81 million and $162 million, respectively, to reduce its deferred tax assets to estimated realizable value. The valuation allowance at December 31, 2018 primarily relates to deferred tax assets for U.K. capital loss carryforwards of $30 million, which have an unlimited carryforward period but can only be utilized against capital gains and U.S. and non-U.S. net operating losses of $27 million and $20 million, respectively. The valuation allowance at December 31, 2017 related to deferred tax assets for U.K. capital loss carryforwards of $28 million, which have an unlimited carryforward period and U.S. and non-U.S. net operating losses of $80 million and $34 million, respectively.

An analysis of our valuation allowance is shown below.

	Years ended December 31,
	2018			2017			2016
Balance at beginning of year	$	162		$	134		$	187
Additions charged to costs and expenses		18			35			—
Additions charged against other accounts		—			—			21
Deductions		(99	)		(7	)		(74	)
Balance at end of year	$	81		$	162		$	134

In 2018, the net change in valuation allowance was an $81 million decrease, of which $80 million was a reduction to tax expense primarily related to an internal U.S. restructuring. In 2017, the amount charged to tax expense in the table above differs from the 2017 rate reconciliation of $13 million because a portion of the valuation allowance increase is related to the U.S. federal corporate tax rate reduction impact on the U.S. state valuation allowance and is included in the impact of U.S. Tax Reform. The amount charged to tax expense in the table above for 2016 differs from the effect of $74 million disclosed in the 2016 rate reconciliation primarily because the movement in this table includes the effects of acquisition accounting, which does not impact tax expense.

The Company recognizes deferred tax balances related to the undistributed earnings of subsidiaries when the Company expects that it will recover those undistributed earnings in a taxable manner, such as through receipt of dividends or sale of the investments. In 2016 we began accruing deferred taxes on the cumulative earnings of certain acquired Towers Watson subsidiaries. The historical cumulative earnings of our other subsidiaries have been reinvested indefinitely.

As a result of U.S. Tax Reform we analyzed our global working capital and cash requirements and the potential tax liabilities attributable to a repatriation and determined we might repatriate up to $219 million, the majority of which was previously deemed indefinitely reinvested. For those investments from which we were able to make a reasonable estimate of the tax effects of such repatriation, we recorded a provisional estimate for foreign withholding taxes and state income taxes of $1 million. In addition, we re-measured the existing deferred tax liability accrued on certain acquired Towers Watson subsidiaries and released the associated deferred tax liability for this item. This resulted in an income tax benefit of $76 million as these foreign earnings were subject to the one-time transition tax. These estimates are now considered final and no further adjustments have been made in the period ended December 31, 2018 as a result of U.S. Tax Reform.

At December 31, 2018, as a result of an international restructuring, we have determined that we may repatriate an additional $2.1 billion, which was previously deemed indefinitely reinvested. As a result we recorded an estimate for foreign withholding and state income tax expense of approximately $11 million.

The cumulative earnings related to amounts reinvested indefinitely as of December 31, 2018 were approximately $7.2 billion, the majority of which are non-U.S. earnings not subject to U.S. tax. As a result, it is not practicable to calculate the tax cost of repatriating these unremitted earnings. If future events, including material changes in estimates of cash, working capital, long-term investment requirements or additional guidance relating to U.S. Tax Reform necessitate that these earnings be distributed, an additional provision for income and foreign withholding taxes, net of credits, may be necessary.

Uncertain tax positions

At December 31, 2018, the amount of unrecognized tax benefits associated with uncertain tax positions, determined in accordance with ASC 740-10, excluding interest and penalties, was $49 million. A reconciliation of the beginning and ending balances of the liability for unrecognized tax benefits is as follows:

	2018			2017			2016
Balance at beginning of year	$	59		$	56		$	22
Increases related to acquisitions		—			—			33
Increases related to tax positions in prior years		2			2			1
Decreases related to tax positions in prior years		(4	)		(5	)		(9	)
Decreases related to settlements		(4	)		—			(1	)
Decreases related to lapse in statute of limitations		(5	)		(2	)		(1	)
Increases related to current year tax positions		3			9			11
Cumulative translation adjustment and other adjustments		(2	)		(1	)		—
Balance at end of year	$	49		$	59		$	56

The liability for unrecognized tax benefits for the years ended December 31, 2018, 2017 and 2016 can be reduced by $2 million, $3 million and $4 million, respectively, of offsetting deferred tax benefits associated with timing differences, foreign tax credits and the federal tax benefit of state income taxes. If these offsetting deferred tax benefits were recognized, there would have been a favorable impact on our effective tax rate. There are no material balances that would result in adjustments to other tax accounts.

Interest and penalties related to unrecognized tax benefits are included as a component of income tax expense. At December 31, 2018, we had cumulative accrued interest of $3 million. At December 31, 2017, the cumulative accrued interest was $5 million. Penalties accrued in 2018 were immaterial and $2 million in 2017.

Tax expense for the years ended December 31, 2018 and 2017 included immaterial interest benefits.

The Company believes that the outcomes which are reasonably possible within the next 12 months may result in a reduction in the liability for unrecognized tax benefits in the range of $1 million to $3 million, excluding interest and penalties.

The Company and its subsidiaries file income tax returns in various tax jurisdictions in which it operates.

Willis North America Inc. is not currently under examination by the IRS. We have ongoing state income tax examinations in certain states for tax years ranging from calendar years ended December 31, 2013 through December 31, 2016. The statute of limitations in certain states extends back to the fiscal year ended June 30, 2014.

All U.K. tax returns have been filed timely and are in the normal process of being reviewed by HM Revenue & Customs. The Company is not currently subject to any material examinations in other jurisdictions. A summary of the tax years that remain open to tax examination in our major tax jurisdictions are as follows:



	Open Tax Years (fiscal year ending in)
U.S. — federal	2015 and forward
U.S. — various states	2013 and forward
U.K.	2010 and forward
Ireland	2014 and forward
France	2010 and forward
Germany	2010 and forward
Canada - federal	2011 and forward

Fixed Assets

12 Months Ended

Dec. 31, 2018

Property Plant And Equipment [Abstract]

Fixed Assets

Note 8 — Fixed Assets

The following table reflects changes in the net carrying amount of the components of fixed assets for the year ended December 31, 2018 and 2017:

	Furniture, equipment and software			Leasehold improvements			Land and buildings			Total
Cost: at January 1, 2017	$	1,009		$	382		$	90		$	1,481
Additions		303			91			—			394
Disposals		(61	)		(21	)		—			(82	)
Foreign exchange		49			16			4			69
Cost: at December 31, 2017		1,300			468			94			1,862
Additions		249			70			—			319
Disposals		(278	)		(35	)		—			(313	)
Reclassification due to ASC 606 ⁽ⁱ⁾		(102	)		—			—			(102	)
Foreign exchange		(39	)		(15	)		(2	)		(56	)
Cost: at December 31, 2018	$	1,130		$	488		$	92		$	1,710

Depreciation: at January 1, 2017	$	(464	)	$	(137	)	$	(41	)	$	(642	)
Depreciation expense ⁽ⁱⁱ⁾		(199	)		(47	)		(6	)		(252	)
Disposals		37			14			—			51
Foreign exchange		(26	)		(6	)		(2	)		(34	)
Depreciation: at December 31, 2017		(652	)		(176	)		(49	)		(877	)
Depreciation expense ⁽ⁱⁱ⁾		(155	)		(54	)		(4	)		(213	)
Disposals		250			27			—			277
Reclassification due to ASC 606 ⁽ⁱ⁾		19			—			—			19
Foreign exchange		19			6			1			26
Depreciation: at December 31, 2018	$	(519	)	$	(197	)	$	(52	)	$	(768	)

Net book value:
At December 31, 2017	$	648		$	292		$	45		$	985

At December 31, 2018	$	611		$	291		$	40		$	942

(i)	Pertains to costs related to certain system implementation activities that have now been included in other non-current assets based on the guidance in ASC 606. See Note 4 — Revenue for further information.

(ii)	Depreciation expense included here does not equal the depreciation expense on the statements of comprehensive income for the years ended December 31, 2018 and 2017 due to the inclusion of $5 million and $49 million, respectively, which have been classified as transaction and integration expenses.

Included within land and buildings are the following assets held under capital leases:

	December 31,
	2018			2017
Capital leases	$	31		$	31
Accumulated depreciation		(16	)		(14	)
	$	15		$	17

Depreciation related to capital leases was $2 million for each of the years ended December 31, 2018, 2017 and 2016.

Goodwill and Other Intangible Assets

12 Months Ended

Dec. 31, 2018

Goodwill And Intangible Assets Disclosure [Abstract]

Goodwill and Other Intangible Assets

Note 9 — Goodwill and Other Intangible Assets

Goodwill

The components of goodwill are outlined below for the years ended December 31, 2018 and 2017:

	HCB			CRB			IRR			BDA		Total
Balance at December 31, 2016
Goodwill, gross	$	4,412		$	2,178		$	1,758		$	2,557	$	10,905
Accumulated impairment losses		(130	)		(362	)		—			—		(492	)
Goodwill, net - December 31, 2016		4,282			1,816			1,758			2,557		10,413
Goodwill reassigned in segment realignment		(113	)		13			100			—		—
Goodwill acquired during the period		—			8			—			—		8
Goodwill disposed of during the period		(31	)		(5	)		(27	)		—		(63	)
Foreign exchange		74			67			20			—		161
Balance at December 31, 2017
Goodwill, gross		4,342			2,261			1,851			2,557		11,011
Accumulated impairment losses		(130	)		(362	)		—			—		(492	)
Goodwill, net - December 31, 2017		4,212			1,899			1,851			2,557		10,519
Goodwill reassigned in segment realignment ⁽ⁱ⁾		—			72			(72	)		—		—
Goodwill acquired during the period		—			9			29			—		38
Goodwill disposed of during the period		—			—			(5	)		—		(5	)
Foreign exchange		(42	)		(34	)		(11	)		—		(87	)
Balance at December 31, 2018
Goodwill, gross		4,300			2,308			1,792			2,557		10,957
Accumulated impairment losses		(130	)		(362	)		—			—		(492	)
Goodwill, net - December 31, 2018	$	4,170		$	1,946		$	1,792		$	2,557	$	10,465

(i)	Represents the reallocation of goodwill related to certain businesses which were realigned among the segments as of January 1, 2018. See Note 5 — Segment Information for further information.

Other Intangible Assets

The following table reflects changes in the net carrying amounts of the components of finite-lived intangible assets for the year ended December 31, 2018:

	Balance at December 31, 2017		Intangible assets acquired		Intangible assets disposed			Amortization ⁽ⁱ⁾			Foreign exchange			Balance at December 31, 2018
Client relationships	$	2,342	$	39	$	(7	)	$	(341	)	$	(47	)	$	1,986
Management contracts		56		—		—			(4	)		(4	)		48
Software		473		—		—			(140	)		(5	)		328
Trademark and trade name		966		—		—			(44	)		(2	)		920
Product		33		—		—			(4	)		(2	)		27
Favorable agreements		10		—		—			(2	)		1			9
Other		2		—		—			(1	)		(1	)		—
Total amortizable intangible assets	$	3,882	$	39	$	(7	)	$	(536	)	$	(60	)	$	3,318

(i)	Amortization associated with favorable lease agreements is recorded in Other operating expenses in the consolidated statements of comprehensive income.

The following table reflects changes in the net carrying amounts of the components of finite-lived intangible assets for the year ended December 31, 2017:

	Balance at December 31, 2016		Intangible assets acquired		Intangible assets disposed			Amortization ⁽ⁱⁱ⁾			Foreign exchange		Balance at December 31, 2017
Client relationships	$	2,655	$	13	$	(44	)	$	(379	)	$	97	$	2,342
Management contracts		54		—		—			(4	)		6		56
Software ⁽ⁱ⁾		570		36		—			(150	)		17		473
Trademark and trade name		1,006		—		(1	)		(44	)		5		966
Product		33		—		—			(3	)		3		33
Favorable agreements		11		1		—			(2	)		—		10
Other		3		—		—			(1	)		—		2
Total amortizable intangible assets	$	4,332	$	50	$	(45	)	$	(583	)	$	128	$	3,882

(i)

In-process research and development intangible assets acquired as part of the Merger on January 4, 2016 of $39 million ($36 million at the date placed into service due to changes in foreign currency exchange rates) had been placed in service during the year ended December 31, 2017 and are included as intangible assets acquired in this presentation.

(ii)	Amortization associated with favorable lease agreements is recorded in Other operating expenses in the consolidated statements of comprehensive income.

We recorded amortization related to our finite-lived intangible assets, exclusive of the amortization of our favorable lease agreements, of $534 million, $581 million and $591 million for the years ended December 31, 2018, 2017 and 2016, respectively.

Our acquired unfavorable lease liabilities were $21 million and $26 million as of December 31, 2018 and December 31, 2017, respectively, and are recorded in other non-current liabilities in the consolidated balance sheet.

The following table reflects the carrying values of finite-lived intangible assets and liabilities at December 31, 2018 and December 31, 2017:

	December 31, 2018					December 31, 2017
	Gross Carrying Amount		Accumulated Amortization			Gross Carrying Amount		Accumulated Amortization
Client relationships	$	3,401	$	(1,415	)	$	3,462	$	(1,120	)
Management contracts		63		(15	)		68		(12	)
Software		749		(421	)		764		(291	)
Trademark and trade name		1,052		(132	)		1,055		(89	)
Product		36		(9	)		39		(6	)
Favorable agreements		14		(5	)		14		(4	)
Other		3		(3	)		6		(4	)
Total finite-lived assets	$	5,318	$	(2,000	)	$	5,408	$	(1,526	)

Unfavorable agreements	$	34	$	(13	)	$	34	$	(8	)
Total finite-lived intangible liabilities	$	34	$	(13	)	$	34	$	(8	)

The weighted-average remaining life of amortizable intangible assets and liabilities at December 31, 2018 was 13.9 years.

The table below reflects the future estimated amortization expense for amortizable intangible assets and the rent offset resulting from amortization of the net lease intangible assets and liabilities for the next five years and thereafter:

Years ended December 31,	Amortization		Rent offset
2019	$	472	$	(2	)
2020		420		(2	)
2021		344		(2	)
2022		287		(3	)
2023		239		(2	)
Thereafter		1,547		(1	)
Total	$	3,309	$	(12	)

Derivative Financial Instruments

12 Months Ended

Dec. 31, 2018

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Derivative Financial Instruments

Note 10 — Derivative Financial Instruments

We are exposed to certain interest rate and foreign currency risks. Where possible, we identify exposures in our business that can be offset internally. Where no natural offset is identified, we may choose to enter into various derivative transactions. These instruments have the effect of reducing our exposure to unfavorable changes in interest and foreign currency rates. The Company’s board of directors reviews and approves policies for managing each of these risks as summarized below. Additional information regarding our derivative financial instruments can be found in Note 2 — Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements, Note 12 — Fair Value Measurements and Note 17 — Accumulated Other Comprehensive Loss.

Interest Rate Risk - Investment Income

As a result of its operating activities, the Company holds fiduciary funds. The Company earns interest on these funds, which is included in its consolidated financial statements in revenue. These funds are regulated in terms of access as are the instruments in which they may be invested, most of which are short-term in nature.

During 2015, in order to manage interest rate risk arising from these financial assets, the Company entered into interest rate swaps to receive a fixed rate of interest and pay a variable rate of interest. These derivatives, with total notional amounts of $300 million, were designated as hedging instruments at December 31, 2017 and had a net fair value liability of $1 million. These derivatives matured during 2018.

Foreign Currency Risk

Certain non-U.S. subsidiaries receive revenue and incur expenses in currencies other than their functional currency, and as a result, the foreign subsidiary’s functional currency revenue will fluctuate as the currency rates change. Additionally, the forecast Pounds sterling expenses of our London brokerage market operations may exceed their Pounds sterling revenue, and they may also hold significant foreign currency asset or liability positions in the consolidated balance sheet. To reduce such variability, we use foreign exchange contracts to hedge against this currency risk.

These derivatives were designated as hedging instruments and at December 31, 2018 and December 31, 2017 had total notional amounts of $438 million and $937 million, respectively, and had net fair value liabilities of $15 million and $21 million, respectively.

At December 31, 2018, the Company estimates, based on current interest and exchange rates, there will be $12 million of net derivative losses on forward exchange rates reclassified from accumulated other comprehensive loss into earnings within the next twelve months as the forecast transactions affect earnings. At December 31, 2018, our longest outstanding maturity was 2 years.

The effects of the material derivative instruments that are designated as hedging instruments on the consolidated statements of comprehensive income for the years ended December 31, 2018, 2017 and 2016 are as follows:

(Loss)/gain

recognized in OCI

(effective element)

Location of loss reclassified from Accumulated OCL into income (effective element)

Loss

reclassified from Accumulated

OCL into income

(effective element)

Location of

loss recognized in

income (ineffective

portion and amount

excluded from

effectiveness testing)

Loss

recognized in income

(ineffective portion and

amount excluded from

effectiveness testing)

2018

2017

2016

2018

2017

2016

2018

2017

2016

Foreign exchange

contracts

(22

)

(127

)

Other income, net

(28

)

(53

)

(42

)

Interest expense

)

We also enter into foreign currency transactions, primarily to hedge certain intercompany loans. These derivatives are not generally designated as hedging instruments and at December 31, 2018 and December 31, 2017, we had notional amounts of $909 million and $971 million, respectively, and had a net fair value asset of $3 million at both December 31, 2018 and 2017.

The effects of derivatives that have not been designated as hedging instruments on the consolidated statements of comprehensive income for the years ended December 31, 2018, 2017 and 2016 are as follows:

	Location of gain/(loss)	Gain/(loss) recognized in income
Derivatives not designated as hedging instruments:	recognized in income	2018		2017		2016
Foreign exchange contracts	Other income, net	$	—	$	11	$	(3	)

Debt

12 Months Ended

Dec. 31, 2018

Debt Disclosure [Abstract]

Debt

Note 11 — Debt

Short-term debt and current portion of long-term debt consists of the following:

	December 31,
	2018		2017
7.000% senior notes due 2019	$	186	$	—
Current portion of term loan due 2019		—		85
	$	186	$	85

Long-term debt consists of the following:

	December 31,
	2018		2017
Revolving $1.25 billion credit facility	$	130	$	884
Term loan due 2019		—		84
7.000% senior notes due 2019		—		186
5.750% senior notes due 2021		498		497
3.500% senior notes due 2021		448		447
2.125% senior notes due 2022 ⁽ⁱ⁾		615		644
4.625% senior notes due 2023		248		248
3.600% senior notes due 2024		645		645
4.400% senior notes due 2026		544		544
4.500% senior notes due 2028		595		—
6.125% senior notes due 2043		271		271
5.050% senior notes due 2048		395		—
	$	4,389	$	4,450

(i)	Notes issued in Euro (€540 million)

Guarantees

All direct obligations under the 5.750% senior notes are issued by Willis Towers Watson and guaranteed by Willis Netherlands B.V., Willis Investment U.K. Holdings Limited, TA I Limited, Trinity Acquisition plc, Willis Group Limited, Willis North America Inc., Willis Towers Watson Sub Holdings Unlimited Company and Willis Towers Watson U.K. Holdings Limited.

All direct obligations under the 7.000%, 3.600%, 4.500% and 5.050% senior notes are issued by Willis North America Inc. and guaranteed by Willis Towers Watson and each of the subsidiaries that guarantees the Company notes, except for Willis North America Inc. itself.

All direct obligations under the 4.625%, 6.125%, 3.500%, 4.400%, and 2.125% senior notes are issued by Trinity Acquisition plc and guaranteed by Willis Towers Watson and each of the subsidiaries that guarantees the Company notes, except for Trinity Acquisition plc itself. See Note 22 — Financial Information for Issuers and Other Guarantor Subsidiaries.

Revolving Credit Facility

$1.25 billion revolving credit facility

On March 7, 2017, Trinity Acquisition plc (see Note 22 for further information) entered into a $1.25 billion amended and restated revolving credit facility (the ‘RCF’), that will mature on March 7, 2022. The RCF replaced the previous $800 million revolving credit facility (see below for further information). Amounts outstanding under the RCF shall bear interest at LIBOR plus a margin of 1.00% to 1.75%, or alternatively, the base rate plus a margin of 0.00% to 0.75%, based upon the Company’s guaranteed senior unsecured long-term debt rating.

Borrowings of $409 million and €45 million against the RCF were used to repay all outstanding borrowings against the previous $800 million revolving credit facility and the 7-year term loan due July 23, 2018.

Additionally, on March 28, 2017, $407 million was used to repay the 6.200% senior notes due 2017, including accrued interest.

Senior Notes

4.500% senior notes due 2028 and 5.050% senior notes due 2048

On September 10, 2018, the Company, together with its wholly-owned subsidiary, Willis North America Inc. as issuer (see Note 22 for further information), completed an offering of $600 million of 4.500% senior notes due 2028 (‘2028 senior notes’) and $400 million of 5.050% senior notes due 2048 (‘2048 senior notes’). The effective interest rates of the 2028 senior notes and 2048 senior notes are 4.504% and 5.073%, respectively, which include the impact of the discount upon issuance. The 2028 senior notes will mature on September 15, 2028 and the 2048 senior notes will mature on September 15, 2048. Interest has accrued on both the 2028 senior notes and 2048 senior notes from September 10, 2018 and will be paid in cash on March 15 and September 15 of each year, commencing on March 15, 2019. The net proceeds from this offering, after deducting underwriter discounts and commissions and estimated offering expenses, were $989 million, and were used to prepay in full $127 million outstanding under the Company’s term loan due December 2019, and to repay a portion of the amount outstanding under the Company’s RCF.

3.600% senior notes due 2024

On May 16, 2017, Willis North America Inc. (see Note 22 for further information) issued $650 million of 3.600% senior notes due 2024 (‘2024 senior notes’). The effective interest rate of the 2024 senior notes is 3.614%, which includes the impact of the discount upon issuance. The 2024 senior notes will mature on May 15, 2024, and interest has accrued on the 2024 senior notes from May 16, 2017 and will be paid in cash on May 15 and November 15 of each year. The net proceeds from this offering, after deducting underwriter discounts and commissions and estimated offering expenses, were $644 million, and were used to pay down amounts outstanding under the RCF and for general corporate purposes.

2.125% senior notes due 2022

On May 26, 2016, Trinity Acquisition plc issued €540 million ($609 million) of 2.125% senior notes due 2022 (‘2022 senior notes’). The effective interest rate of these senior notes is 2.154%, which includes the impact of the discount upon issuance. The 2022 senior notes will mature on May 26, 2022. Interest has accrued on the notes from May 26, 2016 and will be paid in cash on May 26 of each year. The net proceeds from this offering, after deducting underwriter discounts and commissions and estimated offering expenses, were €535 million ($600 million). We used the net proceeds of this offering to repay Tranche A of the previous 1-year term loan facility, which matured in 2016, and related accrued interest.

3.500% senior notes due 2021 and 4.400% senior notes due 2026

On March 22, 2016, Trinity Acquisition plc issued $450 million of 3.500% senior notes due 2021 (‘2021 senior notes’) and $550 million of 4.400% senior notes due 2026 (‘2026 senior notes’). The effective interest rates of these senior notes are 3.707% and 4.572%, respectively, which include the impact of the discount upon issuance. The 2021 senior notes and the 2026 senior notes will mature on September 15, 2021 and March 15, 2026, respectively. Interest has accrued on the notes from March 22, 2016 and will be paid in cash on March 15 and September 15 of each year. The net proceeds from these offerings, after deducting underwriter discounts and commissions and estimated offering expenses, were $988 million. We used the net proceeds of these offerings to: (i) repay $300 million principal under the prior $800 million revolving credit facility and related accrued interest, which was drawn to repay our previously issued 4.125% senior notes on March 15, 2016; (ii) repay $400 million principal on Tranche B of the previous 1-year term loan facility and related accrued interest; and (iii) pay down a portion of the remaining principal amount outstanding under the previous $800 million revolving credit facility (see below for further information) and related accrued interest.

4.625% senior notes due 2023 and 6.125% senior notes due 2043

On August 15, 2013, the Company issued $250 million of 4.625% senior notes due 2023 and $275 million of 6.125% senior notes due 2043. The effective interest rates of these senior notes are 4.696% and 6.154%, respectively, which include the impact of the discount upon issuance. The proceeds were used to repurchase other previously issued senior notes.

5.750% senior notes due 2021

In March 2011, the Company issued $500 million of 5.750% senior notes due 2021. The effective interest rate of this senior note is 5.871%, which includes the impact of the discount upon issuance. The proceeds were used to repurchase and redeem other previously issued senior notes.

7.000% senior notes due 2019

In September 2009, Willis North America Inc. issued $300 million of 7.000% senior notes due 2019. The effective interest rate of these senior notes is 7.081%, which includes the impact of the discount upon issuance. A portion of the proceeds were used to repurchase and redeem other previously-issued senior notes. In August 2013, $113 million of the 7.000% senior notes due 2019 were repurchased.

Term Loan Facilities

Term loan due December 2019

On January 4, 2016, we acquired a $340 million term loan in connection with the Merger. On November 20, 2015, Towers Watson Delaware Inc. entered into a 4-year amortizing term loan agreement for up to $340 million with a consortium of banks to help fund the pre-Merger special dividend. On December 28, 2015, Towers Watson Delaware Inc. borrowed the full $340 million. During 2018, we prepaid the remaining $127 million outstanding under the term loan with proceeds from the issuance of the 2028 senior notes and 2048 senior notes discussed above.

Additional Information Regarding Fully Repaid Revolving Credit Facility, Term Loan Facilities and Senior Notes

$800 million revolving credit facility

Drawings under the previous $800 million revolving credit facility bore interest at LIBOR plus a margin of 1.25% to 2.00%, or alternatively the base rate plus a margin of 0.25% to 1.00% based upon the Company’s guaranteed senior unsecured long-term debt rating; a 1.375% margin applied while the Company’s debt rating remained BBB/Baa3.

7-year term loan facility

The 7-year term loan facility expiring 2018 bore interest at the same rate applicable to the previous $800 million revolving credit facility and was repayable in quarterly installments of $6 million with a final repayment of $186 million due in the third quarter of 2018. During 2017, we repaid in full and terminated the 7-year term loan with proceeds from borrowings against our $1.25 billion revolving credit facility.

1-year term loan facility

On November 20, 2015, Legacy Willis entered into a 1-year term loan facility. The 1-year term loan had two tranches: Tranche A was for €550 million, of which €544 million ($592 million) was drawn on December 19, 2015 and used to finance the acquisition of Gras Savoye. Tranche B was for $400 million and was drawn on January 4, 2016 and used to re-finance debt held by Legacy Towers Watson which became due on acquisition. Tranche A was repaid in its entirety on May 26, 2016 from the proceeds from the issuance of our 2022 senior notes discussed above. Tranche B was repaid in its entirety on March 22, 2016 from a portion of the proceeds from the issuance of our senior notes discussed above.

4.125% senior notes due 2016

In March 2011, the Company issued $300 million of 4.125% senior notes due 2016. The effective interest rate of the senior notes was 4.240%, which included the impact of the discount upon issuance. The proceeds were used to repurchase and redeem other previously issued senior notes. The 4.125% senior notes were repaid in March 2016.

6.200% senior notes due 2017

On March 28, 2007, we issued $600 million of 10-year senior notes at 6.200%. The effective interest rate of these senior notes was 6.253%. In August 2013, $206 million of the 6.200% senior notes was repurchased. The final balance was repaid on March 28, 2017 from the RCF as discussed above.

Covenants

The terms of our current financings also include certain limitations. For example, the agreements relating to the debt arrangements and credit facilities generally contain numerous operating and financial covenants, including requirements to maintain minimum ratios of consolidated EBITDA to consolidated cash interest expense and maximum levels of consolidated funded indebtedness in relation to consolidated EBITDA, in each case subject to certain adjustments. The operating restrictions and financial covenants in our current credit facilities do, and any future financing agreements may, limit our ability to finance future operations or capital needs or to engage in other business activities. At December 31, 2018 and 2017, we were in compliance with all financial covenants.

Debt Maturity

The following table summarizes the maturity of our debt, interest on senior notes and excludes any reduction for debt issuance costs:

	2019		2020		2021		2022		2023		Thereafter		Total
Senior notes	$	187	$	—	$	950	$	617	$	250	$	2,475	$	4,479
Interest on senior notes		191		181		153		128		119		1,019		1,791
RCF		—		—		—		130		—		—		130
Total	$	378	$	181	$	1,103	$	875	$	369	$	3,494	$	6,400

Interest Expense

The following table shows an analysis of the interest expense for the years ended December 31:

	Years ended December 31,
	2018		2017		2016
Senior notes	$	166	$	148	$	139
Term loans		4		8		17
RCF		26		17		10
WSI revolving credit facility		—		1		2
Other⁽ⁱ⁾		12		14		16
Total interest expense	$	208	$	188	$	184

(i)	Other primarily includes debt issuance costs, interest expense on capitalized leases and accretion on deferred and contingent consideration.

Fair Value Measurements

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Fair Value Measurements

Note 12 — Fair Value Measurements

The Company has categorized its assets and liabilities that are measured at fair value on a recurring and non-recurring basis into a three-level fair value hierarchy, based on the reliability of the inputs used to determine fair value as follows:

•

Level 1: refers to fair values determined based on quoted market prices in active markets for identical assets;

•

Level 2: refers to fair values estimated using observable market-based inputs or unobservable inputs that are corroborated by market data; and

•

Level 3: includes fair values estimated using unobservable inputs that are not corroborated by market data.

The following methods and assumptions were used by the Company in estimating its fair value disclosure for financial instruments:

•

Available-for-sale securities are classified as Level 1 because we use quoted market prices in determining the fair value of these securities.

•

Market values for our derivative instruments have been used to determine the fair values of interest rate swaps and forward foreign exchange contracts based on estimated amounts the Company would receive or have to pay to terminate the agreements, taking into account observable information about the current interest rate environment or current foreign currency forward rates. Such financial instruments are classified as Level 2 in the fair value hierarchy.

•

Contingent consideration payable is classified as Level 3, and we estimate fair value based on the likelihood and timing of achieving the relevant milestones of each arrangement, applying a probability assessment to each of the potential outcomes, and discounting the probability-weighted payout. Typically, milestones are based on revenue or EBITDA growth for the acquired business.

The following tables present our assets and liabilities measured at fair value on a recurring basis at December 31, 2018 and December 31, 2017:

		Fair Value Measurements on a Recurring Basis at December 31, 2018
	Balance Sheet Location	Level 1		Level 2		Level 3		Total
Assets:
Available-for-sale securities:
Mutual funds / exchange traded funds	Prepaid and other current assets and other non-current assets	$	18	$	—	$	—	$	18
Derivatives:
Derivative financial instruments ⁽ⁱ⁾	Prepaid and other current assets and other non-current assets	$	—	$	5	$	—	$	5
Liabilities:
Contingent consideration:
Contingent consideration ⁽ⁱⁱ⁾	Other current liabilities and other non-current liabilities	$	—	$	—	$	51	$	51
Derivatives:
Derivative financial instruments ⁽ⁱ⁾	Other current liabilities and other non-current liabilities	$	—	$	17	$	—	$	17

		Fair Value Measurements on a Recurring Basis at December 31, 2017
	Balance Sheet Location	Level 1		Level 2		Level 3		Total
Assets:
Available-for-sale securities:
Mutual funds / exchange traded funds	Prepaid and other current assets and other non-current assets	$	40	$	—	$	—	$	40
Derivatives:
Derivative financial instruments ⁽ⁱ⁾	Prepaid and other current assets and other non-current assets	$	—	$	18	$	—	$	18
Liabilities:
Contingent consideration:
Contingent consideration ⁽ⁱⁱ⁾	Other current liabilities and other non-current liabilities	$	—	$	—	$	51	$	51
Derivatives:
Derivative financial instruments ⁽ⁱ⁾	Other current liabilities and other non-current liabilities	$	—	$	37	$	—	$	37

(i)	See Note 10 — Derivative Financial Instruments for further information on our derivative instruments.

(ii)

Probability weightings are based on our knowledge of the past and planned performance of the acquired entity to which the contingent consideration applies. The weighted-average discount rates used on our material contingent consideration calculations were 9.92% and 9.64% at December 31, 2018 and December 31, 2017, respectively. Using different probability weightings and discount rates could result in an increase or decrease of the contingent consideration payable.

The following table summarizes the change in fair value of the Level 3 liabilities:

Fair Value Measurements Using Significant Unobservable Inputs (Level 3)	December 31, 2018
Balance at December 31, 2017	$	51
Obligations assumed		2
Payments		(3	)
Realized and unrealized gains		3
Foreign exchange		(2	)
Balance at December 31, 2018	$	51

There were no significant transfers between Levels 1, 2 or 3 during the years ended December 31, 2018 and 2017.

Fair value information about financial instruments not measured at fair value

The following tables present our liabilities not measured at fair value on a recurring basis at December 31, 2018 and 2017:

	December 31, 2018				December 31, 2017
	Carrying Value		Fair Value		Carrying Value		Fair Value
Liabilities:
Short-term debt and current portion of long-term debt	$	186	$	191	$	85	$	85
Long-term debt	$	4,389	$	4,458	$	4,450	$	4,706

The carrying values of our revolving lines of credit and term loans approximate their fair values. The fair values above are not necessarily indicative of the amounts that the Company would realize upon disposition nor do they indicate the Company’s intent or ability to dispose of the financial instrument. The fair value of our respective senior notes are considered level 2 financial instruments as they are corroborated by observable market data.

Compensation And Retirement Disclosure [Abstract]

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Retirement Benefits

12 Months Ended

Dec. 31, 2018

Retirement Benefits

Note 13 — Retirement Benefits

Defined Benefit Plans and Post-retirement Welfare Plans

Willis Towers Watson sponsors both qualified and non-qualified defined benefit pension plans and other post-retirement welfare (‘PRW’) plans throughout the world. The majority of our plan assets and obligations are in the United States and the United Kingdom. We have also included disclosures related to defined benefit plans in certain other countries, including Canada, France, Germany, Ireland and the Netherlands. Together, these disclosed funded and unfunded plans represent 99% of Willis Towers Watson’s pension and PRW obligations and are disclosed herein.

As part of these obligations, in the United States, the United Kingdom and Canada, we have non-qualified plans that provide for the additional pension benefits that would be covered under the qualified plan in the respective country were it not for statutory maximums. The non-qualified plans are unfunded.

The significant plans within each grouping are described below:

United States

Legacy Willis – This plan was frozen in 2009. Approximately one-quarter of the Legacy Willis employees in the United States have a frozen accrued benefit under this plan.

Willis Towers Watson Plan – Substantially all U.S. employees are eligible to participate in this plan. Benefits are provided under a stable value pension plan design. The original stable value design came into effect on January 1, 2012. Existing plan participants as of July 1, 2017 earn benefits without having to make employee contributions, and all newly eligible employees after that date are required to contribute 2% of pay to participate in the plan.

United Kingdom

Legacy Willis – This plan covers approximately one-third of the Legacy Willis employees in the United Kingdom. The plan is now closed to new entrants. New employees in the United Kingdom are offered the opportunity to join a defined contribution plan.

Legacy Towers Watson – Benefit accruals earned under the Legacy Watson Wyatt defined benefit plan (predominantly pension benefits) ceased on February 28, 2015, although benefits earned prior to January 1, 2008 retain a link to salary until the employee leaves the Company. Benefit accruals earned under the legacy Towers Perrin defined benefit plan (predominantly lump sum benefits) were frozen on March 31, 2008. All participants now accrue defined contribution benefits.

Legacy Miller – The plan provides retirement benefits based on members’ salaries at the point at which they ceased to accrue benefits under the scheme.

Other

Canada (Legacy Towers Watson) – Participants accrue qualified and non-qualified benefits based on a career average benefit formula. Additionally, participants can choose to make voluntary contributions to purchase enhancements to their pension.

France (Legacy Gras Savoye) – The mandatory retirement indemnity plan is a termination benefit which provides lump sum benefits at retirement. There is no vesting before the retirement date and the benefit formula is determined through the collective bargaining agreement and the labor code. All employees with permanent employment contracts are eligible.

Germany (Legacy Willis and Legacy Towers Watson) – Both defined benefit plans are closed to new entrants and include certain legacy employee populations hired before 2011. These benefits are primarily account-based, with some long-service participants continuing to accrue benefits according to grandfathered final-average–pay formulas. Other employees, including new entrants, participate in defined contribution arrangements.

Ireland (Legacy Willis) – The defined benefit plans provide pension benefits for approximately one-third of legacy Willis employees in Ireland. The defined benefit plans are now closed to new entrants.

Ireland (Legacy Towers Watson) – Benefit accruals earned under the scheme’s defined benefit plan ceased on May 1, 2015. Benefits earned prior to this date retain a link to salary until the employee leaves the Company.

Netherlands (Legacy Towers Watson) – This plan was terminated during the year ended December 31, 2018. Benefits under the plan accrued on a final pay basis on earnings up to a maximum amount each year, however this accrual stopped at December 31, 2010. The accrued benefits received conditional indexation each year prior to the plan termination.

Post-retirement Welfare Plan

We provide certain healthcare and life insurance benefits for retired participants. The principal plans cover participants in the U.S. who have met certain eligibility requirements. Our principal post-retirement benefit plans are primarily unfunded. Retiree medical benefits provided under our U.S. post-retirement benefit plans were closed to new hires effective January 1, 2011. Life insurance benefits under the plans were frozen with respect to service, eligibility and amounts as of January 1, 2012 for active participants.

Amounts Recognized in our Consolidated Financial Statements

The following schedules provide information concerning the defined benefit pension plans and PRW plan as of and for the years ended December 31, 2018 and 2017:

	2018												2017
	U.S.			U.K.			Other			PRW			U.S.			U.K.			Other			PRW
Change in Benefit Obligation
Benefit obligation, beginning of year	$	4,476		$	4,165		$	822		$	123		$	4,169		$	3,899		$	732		$	113
Service cost		66			18			21			1			66			32			20			—
Interest cost		140			95			18			4			139			93			17			4
Employee contributions		14			1			—			7			6			1			—			6
Actuarial (gains)/losses		(313	)		(176	)		(7	)		(3	)		293			2			5			14
Settlements		(11	)		(152	)		(26	)		—			(16	)		(138	)		(1	)		—
Curtailments		—			—			(20	)		—			—			—			—			—
Benefits paid		(185	)		(96	)		(28	)		(14	)		(181	)		(93	)		(29	)		(14	)
Plan amendments		—			40			—			(31	)		—			—			—			—
Transfers in		—			—			1			—			—			—			1			—
Foreign currency changes		—			(229	)		(53	)		—			—			369			77			—
Benefit obligation, end of year	$	4,187		$	3,666		$	728		$	87		$	4,476		$	4,165		$	822		$	123
Change in Plan Assets
Fair value of plan assets, beginning of year	$	3,654		$	4,910		$	562		$	2		$	3,280		$	4,360		$	467		$	4
Actual return on plan assets		(157	)		(69	)		(9	)		—			464			290			42			—
Employer contributions		88			85			22			6			101			66			34			6
Employee contributions		14			1			—			7			6			1			—			6
Settlements		(11	)		(152	)		(26	)		—			(16	)		(138	)		(1	)		—
Benefits paid		(185	)		(96	)		(28	)		(14	)		(181	)		(93	)		(29	)		(14	)
Transfers in		—			—			1			—			—			—			1			—
Foreign currency adjustment		—			(277	)		(36	)		—			—			424			48			—
Fair value of plan assets, end of year	$	3,403		$	4,402		$	486		$	1		$	3,654		$	4,910		$	562		$	2
Funded status at end of year	$	(784	)	$	736		$	(242	)	$	(86	)	$	(822	)	$	745		$	(260	)	$	(121	)
Accumulated Benefit Obligation	$	4,187		$	3,666		$	698		$	87		$	4,476		$	4,165		$	790		$	123
Components on the Consolidated Balance Sheet
Pension benefits assets	$	—		$	745		$	17		$	—		$	—		$	754		$	17		$	—
Current liability for pension benefits	$	(49	)	$	(1	)	$	(6	)	$	(5	)	$	(40	)	$	—		$	(6	)	$	(5	)
Non-current liability for pension benefits	$	(735	)	$	(8	)	$	(253	)	$	(81	)	$	(782	)	$	(9	)	$	(271	)	$	(116	)
	$	(784	)	$	736		$	(242	)	$	(86	)	$	(822	)	$	745		$	(260	)	$	(121	)

Amounts recognized in accumulated other comprehensive loss as of December 31, 2018 and 2017 consist of:

	2018										2017
	U.S.		U.K.			Other		PRW			U.S.		U.K.			Other		PRW
Net actuarial loss	$	769	$	955		$	98	$	16		$	663	$	909		$	79	$	19
Net prior service gain		—		(76	)		—		(31	)		—		(142	)		—		—
Accumulated other comprehensive loss/(income)	$	769	$	879		$	98	$	(15	)	$	663	$	767		$	79	$	19

The following table presents the projected benefit obligation and fair value of plan assets for our plans that have a projected benefit obligation in excess of plan assets as of December 31, 2018 and 2017:

	2018						2017
	U.S.		U.K.		Other		U.S.		U.K.		Other
Projected benefit obligation at end of year	$	4,187	$	9	$	672	$	4,476	$	10	$	758
Fair value of plan assets at end of year	$	3,403	$	—	$	413	$	3,654	$	—	$	481

The following table presents the projected benefit obligation, accumulated benefit obligation and fair value of plan assets for our plans that have an accumulated benefit obligation in excess of plan assets as of December 31, 2018 and 2017.

	2018						2017
	U.S.		U.K.		Other		U.S.		U.K.		Other
Projected benefit obligation at end of year	$	4,187	$	9	$	672	$	4,476	$	10	$	758
Accumulated benefit obligation at end of year	$	4,187	$	9	$	642	$	4,476	$	10	$	726
Fair value of plan assets at end of year	$	3,403	$	—	$	413	$	3,654	$	—	$	481

The components of the net periodic benefit income and other amounts recognized in other comprehensive (income)/loss for the years ended December 31, 2018, 2017 and 2016 for the defined benefit pension and PRW plans are as follows:

	2018												2017											2016
	U.S.			U.K.			Other			PRW			U.S.			U.K.			Other			PRW		U.S.			U.K.			Other			PRW
Components of net periodic benefit (income)/cost:
Service cost	$	66		$	18		$	21		$	1		$	66		$	32		$	20		$	—	$	59		$	24		$	19		$	1
Interest cost		140			95			18			4			139			93			17			4		137			114			18			3
Expected return on plan assets		(273	)		(298	)		(31	)		—			(245	)		(284	)		(30	)		—		(240	)		(253	)		(27	)		—
Amortization of unrecognized prior service credit		—			(19	)		—			—			—			(18	)		—			—		—			(19	)		—			—
Amortization of unrecognized actuarial loss		11			45			2			—			13			53			2			—		12			42			—			—
Settlement		1			41			2			—			1			37			1			—		—			—			5			—
Curtailment gain		—			—			(16	)		—			—			—			—			—		—			—			—			—
Net periodic benefit (income)/cost	$	(55	)	$	(118	)	$	(4	)	$	5		$	(26	)	$	(87	)	$	10		$	4	$	(32	)	$	(92	)	$	15		$	4
Other changes in plan assets and benefit obligations recognized in other comprehensive loss/(income):
Net actuarial loss/(gain)	$	117		$	191		$	13		$	(3	)	$	74		$	(4	)	$	(7	)	$	14	$	238		$	323		$	62		$	4
Amortization of unrecognized actuarial loss		(11	)		(45	)		(2	)		—			(13	)		(53	)		(2	)		—		(12	)		(42	)		—			—
Prior service cost/(credit)		—			40			—			(31	)		—			—			—			—		—			—			—			—
Amortization of unrecognized prior service credit		—			19			—			—			—			18			—			—		—			19			—			—
Settlement		(1	)		(41	)		(2	)		—			(1	)		(37	)		(1	)		—		—			—			(8	)		—
Curtailment gain		—			—			16			—			—			—			—			—		—			—			—			—
Total recognized in other comprehensive loss/(income)		105			164			25			(34	)		60			(76	)		(10	)		14		226			300			54			4
Total recognized in net periodic benefit (income)/cost and other comprehensive loss/(income)	$	50		$	46		$	21		$	(29	)	$	34		$	(163	)	$	—		$	18	$	194		$	208		$	69		$	8

As a result of adopting ASU 2017-07, within the consolidated statements of comprehensive income, service cost is included within salaries and benefits expense. The remainder of the components of net periodic benefit income of $280 million, $222 million and $203 million for the years ended December 31, 2018, 2017 and 2016, respectively, are included within other income, net. These reclassifications include amounts for those plans which are immaterial for disclosure.

During the year ended December 31, 2018, the Company terminated its Netherlands-based defined benefit plan, resulting in the recognition of a non-cash curtailment gain of $16 million.

During the years ended December 31, 2018 and 2017, as a result of past changes in UK legislation and the low interest rate environment, the amount of transfer payments from the Legacy Willis UK pension plan exceeded the plan’s service and interest cost. This triggers settlement accounting which requires immediate recognition of a portion of the obligations associated with the plan transfers. Consequently, the Company recognized a non-cash expense of $40 million and $36 million for the years ended December 31, 2018 and 2017, respectively.

During the year ended December 31, 2016, we adopted the granular approach to calculating service and interest costs. This was treated as a change in accounting estimate, and resulted in a credit of $51 million included in our total net periodic benefit income reflected above.

The estimated net actuarial loss and prior service credit for the defined benefit plans that will be amortized from accumulated other comprehensive loss into net periodic benefit cost over the next fiscal year are:

	For the Year Ended December 31, 2019
	U.S.		U.K			Other		PRW
Estimated net actuarial loss	$	19	$	21		$	2	$	1
Prior service credit	$	—	$	(16	)	$	—	$	(4	)

Assumptions Used in the Valuations of the Defined Benefit Pension Plans and PRW Plan

The determination of the Company’s obligations and annual expense under the plans is based on a number of assumptions that, given the longevity of the plans, are long-term in focus. A change in one or a combination of these assumptions could have a material impact on our projected benefit obligation. However, certain of these changes, such as changes in the discount rate and actuarial assumptions, are not recognized immediately in net income, but are instead recorded in other comprehensive income. The accumulated gains and losses not yet recognized in net income are amortized into net income as a component of the net periodic benefit cost/(income) generally based on the average working life expectancy of each of the plan’s active participants to the extent that the net gains or losses as of the beginning of the year exceed 10% of the greater of the market-related value of plan assets or the projected benefit obligation. The average remaining service period of participants for the PRW plan is approximately 10.6 years.

The Company considers several factors prior to the start of each fiscal year when determining the appropriate annual assumptions, including economic forecasts, relevant benchmarks, historical trends, portfolio composition and peer company comparisons. These assumptions, used to determine our pension liabilities and pension expense, are reviewed annually by senior management and changed when appropriate. A discount rate will be changed annually if underlying rates have moved, whereas an expected long-term return on assets will be changed less frequently as longer term trends in asset returns emerge or long-term target asset allocations are revised. To calculate the discount rate, we use the granular approach to determining service and interest costs. The expected rate of return assumptions for all plans are supported by an analysis of the weighted-average yield expected to be achieved based upon the anticipated makeup of the plans’ investments. Other material assumptions include rates of participant mortality, and the expected long-term rate of compensation and pension increases.

The following assumptions were used in the valuations of Willis Towers Watson’s defined benefit pension plans and PRW plan. The assumptions presented for the U.S. plans represent the weighted-average of rates for all U.S. plans. The assumptions presented for the U.K. plans represent the weighted-average of rates for the U.K. plans. The assumptions presented for the Other plans represent the weighted-average of rates for the Canada, France, Germany, Ireland, and Netherlands plans. The Netherlands plan is excluded from the 2018 disclosures due to the plan termination during the year.

The assumptions used to determine net periodic benefit cost for the fiscal years ended December 31, 2018, 2017, and 2016 were as follows:

	Years ended December 31,
	2018												2017												2016
	U.S.			U.K.			Other			PRW			U.S.			U.K.			Other			PRW			U.S.			U.K.			Other			PRW
Discount rate - PBO		3.6	%		2.6	%		2.6	%		3.5	%		4.0	%		2.6	%		2.7	%		4.0	%		4.2	%		3.8	%		3.2	%		4.2	%
Discount rate - service cost		3.5	%		2.7	%		2.9	%		3.5	%		3.9	%		2.6	%		3.0	%		3.9	%		3.9	%		3.8	%		3.4	%		4.1	%
Discount rate - interest cost on service cost		3.1	%		2.5	%		2.7	%		3.2	%		3.2	%		2.4	%		2.8	%		3.5	%		3.2	%		3.8	%		3.1	%		3.5	%
Discount rate - interest cost on PBO		3.2	%		2.3	%		2.3	%		3.1	%		3.4	%		2.3	%		2.3	%		3.3	%		3.4	%		3.4	%		2.8	%		3.3	%
Expected long-term rate of return on assets		7.6	%		6.2	%		5.7	%		2.0	%		7.6	%		6.3	%		6.1	%		2.0	%		7.6	%		6.2	%		6.1	%		2.0	%
Rate of increase in compensation levels		4.3	%		3.0	%		2.3	%	N/A				4.3	%		3.2	%		2.3	%	N/A				4.3	%		3.2	%		2.3	%	N/A
Healthcare cost trend
Initial rate											6.5	%											7.0	%											7.0	%
Ultimate rate											5.0	%											5.0	%											5.0	%
Year reaching ultimate rate										2022												2022												2022

The following tables present the assumptions used in the valuation to determine the projected benefit obligation for the fiscal years ended December 31, 2018 and 2017:

	December 31, 2018												December 31, 2017
	U.S.			U.K.			Other			PRW			U.S.			U.K.			Other			PRW
Discount rate		4.2	%		2.8	%		2.8	%		4.2	%		3.6	%		2.6	%		2.6	%		3.5	%
Rate of increase in compensation levels		4.3	%		3.0	%		2.3	%	N/A				4.3	%		3.0	%		2.3	%	N/A

A one percentage point change in the assumed healthcare cost trend rates would have an immaterial effect on the post-retirement benefit cost and obligation as of December 31, 2018.

The expected return on plan assets was determined on the basis of the weighted-average of the expected future returns of the various asset classes, using the target allocations shown below. The Company’s pension plan asset target allocations as of December 31, 2018 were as follows:

	U.S.						U.K.									Canada			Germany			Ireland
Asset Category	Willis			Willis Towers Watson			Willis			Towers Watson			Miller			Towers Watson			Towers Watson			Willis			Towers Watson
Equity securities		30	%		23	%		23	%		7	%		19	%		40	%		34	%		30	%		40	%
Debt securities		44	%		43	%		58	%		25	%		21	%		50	%		59	%		29	%		30	%
Real estate		11	%		6	%		2	%		1	%		—	%		5	%		—	%		3	%		—	%
Other		15	%		28	%		17	%		67	%		60	%		5	%		7	%		38	%		30	%
Total		100	%		100	%		100	%		100	%		100	%		100	%		100	%		100	%		100	%

The Legacy Willis plan in Germany is invested in insurance contracts. Consequently, the asset allocations of the plans are managed by the respective insurer. The Legacy Gras Savoye plan in France is unfunded.

Our investment strategy is designed to generate returns that will reduce the interest rate risk inherent in each of the plan’s benefit obligations and enable the plans to meet their future obligations. The precise amount for which these obligations will be settled depends on future events, including the life expectancy of the plan participants and salary inflation. The obligations are estimated using actuarial assumptions, based on the current economic environment.

Each pension plan seeks to achieve total returns sufficient to meet expected future obligations when considered in conjunction with expected future contributions and prudent levels of investment risk and diversification. Each plan’s targeted asset allocation is generally determined through a plan-specific asset-liability modeling study. These comprehensive studies provide an evaluation of the projected status of asset and benefit obligation measures for each plan under a range of both positive and negative factors. The studies include a number of different asset mixes, spanning a range of diversification and potential equity exposures.

In evaluating the strategic asset allocation choices, an emphasis is placed on the long-term characteristics of each individual asset class, such as expected return, volatility of returns and correlations with other asset classes within the portfolios. Consideration is also given to the proper long-term level of risk for each plan, the impact of the volatility and magnitude of plan contributions and costs, and the impact that certain actuarial techniques may have on the plan’s recognition of investment experience.

We monitor investment performance and portfolio characteristics on a quarterly basis to ensure that managers are meeting expectations with respect to their investment approach. There are also various restrictions and controls placed on managers, including prohibition from investing in our stock.

Fair Value of Plan Assets

The fair value hierarchy has three levels based on the reliability of the inputs used to determine fair value:

•

Level 1: refers to fair values determined based on quoted market prices in active markets for identical assets;

•

Level 2: refers to fair values estimated using observable market-based inputs or unobservable inputs that are corroborated by market data; and

•

Level 3: includes fair values estimated using unobservable inputs that are not corroborated by market data.

The fair values of our U.S. plan assets by asset category at December 31, 2018 and 2017 are as follows:

	December 31, 2018								December 31, 2017
	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
Asset category:
Cash	$	6	$	—	$	—	$	6	$	10	$	—	$	—	$	10
Short-term securities		—		78		—		78		—		283		—		283
Equity securities		156		—		—		156		202		—		—		202
Government bonds		2		—		—		2		10		—		—		10
Corporate bonds		—		354		—		354		—		193		—		193
Other fixed income		—		—		—		—		—		20		—		20
Pooled / commingled funds		—		—		—		1,467		—		—		—		1,922
Mutual funds		—		—		—		—		1		—		—		1
Private equity		—		—		—		357		—		—		—		287
Hedge funds		—		—		—		984		—		—		—		724
Total assets	$	164	$	432	$	—	$	3,404	$	223	$	496	$	—	$	3,652

The fair values of our U.K. plan assets by asset category at December 31, 2018 and 2017 are as follows:

	December 31, 2018									December 31, 2017
	Level 1		Level 2			Level 3		Total		Level 1		Level 2		Level 3		Total
Asset category:
Cash	$	229	$	—		$	—	$	229	$	92	$	—	$	—	$	92
Equity securities		—		—			—		—		24		—		—		24
Government bonds		1,804		—			—		1,804		1,841		—		—		1,841
Corporate bonds		—		297			—		297		—		224		—		224
Other fixed income		—		248			—		248		—		246		—		246
Pooled / commingled funds		—		—			—		934		—		—		—		2,294
Mutual funds		—		—			—		16		—		—		—		8
Private equity		—		—			—		33		—		—		—		32
Derivatives		—		96			—		96		—		102		—		102
Real estate		—		—			—		184		—		—		—		218
Hedge funds		—		—			—		1,232		—		—		—		393
Total assets	$	2,033	$	641		$	—	$	5,073	$	1,957	$	572	$	—	$	5,474

Liability category:
Repurchase agreements		—		684			—		684		—		549		—		549
Derivatives		—		—			—		—		—		16		—		16
Net assets/(liabilities)	$	2,033	$	(43	)	$	—	$	4,389	$	1,957	$	7	$	—	$	4,909

The fair values of our Other plan assets by asset category at December 31, 2018 and 2017 are as follows:

	December 31, 2018								December 31, 2017
	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
Asset category:
Cash	$	1	$	—	$	—	$	1	$	5	$	—	$	—	$	5
Pooled / commingled funds		—		—		—		294		—		—		—		327
Mutual funds		—		—		—		185		—		—		—		209
Hedge funds		—		—		—		4		—		—		—		—
Insurance contracts		—		—		2		2		—		—		19		19
Total assets	$	1	$	—	$	2	$	486	$	5	$	—	$	19	$	560

Our PRW plan invests only in short-term investments and mutual funds and is not included within this fair value hierarchy table.

We evaluate the need to transfer between levels based upon the nature of the financial instrument and size of the transfer relative to the total net assets of the plans. There were no significant transfers between Levels 1, 2 or 3 in the fiscal years ended December 31, 2018 and 2017.

In accordance with Subtopic 820-10, Fair Value Measurement and Disclosures, certain investments that are measured at fair value using the net asset value per share practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in these tables are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the statements of net assets.

Following is a description of the valuation methodologies used for investments at fair value:

Short-term securities: Valued at the net value of shares held by the Company at year end as reported by the sponsor of the funds.

Equity securities and mutual funds: Valued at the closing price reported on the active market on which the individual securities are traded. Exchange-traded mutual funds are included as Level 1 above.

Government bonds: Valued at the closing price reported in the active market in which the bond is traded.

Corporate bonds: Valued using pricing models maximizing the use of observable inputs for similar securities. This includes basing values on yields currently available on comparable securities of issuers with similar credit ratings.

Other fixed income: Foreign and municipal bonds are valued at the closing price reported in the active market in which the bond is traded.

Pooled / commingled funds and mutual funds: Valued at the net value of shares held by the Company at year end as reported by the manager of the funds. These funds are not exchange-traded and are not reported by level in the tables above.

Derivative investments: Valued at the closing level of the relevant index or security and interest accrual through the valuation date.

Private equity funds, real estate funds, hedge funds: The fair values for these investments are estimated based on the net asset values derived from the latest audited financial statements or most recent capital account statements provided by the private equity fund’s investment manager or third-party administrator.

Insurance contracts: The fair values are determined using model-based techniques that include option-pricing models, discounted cash flow models and similar techniques.

Repurchase agreements: Valued as the repurchase obligation which includes an interest rate linked to the underlying fixed interest government bond portfolio. These agreements are short-term in nature (less than one year) and were entered into for the purpose of purchasing additional government bonds.

The following table reconciles the net plan investments to the total fair value of the plan assets:

	December 31,
	2018			2017
Net assets held in investments	$	8,279		$	9,121
PRW plan assets		1			2
Net (payable)/receivable for investments purchased		(1	)		2
Dividend and interest receivable		1			3
Other adjustments		12			—
Fair value of plan assets	$	8,292		$	9,128

Level 3 investments

As a result of the inherent limitations related to the valuations of the Level 3 investments, due to the unobservable inputs of the underlying funds, the estimated fair value may differ significantly from the values that would have been used had a market for those investments existed.

The following table sets forth a summary of changes in the fair value of the plans’ Level 3 assets for the fiscal year ended December 31, 2018:

	Level 3 Roll Forward
Beginning balance at December 31, 2017	$	19
Plan termination	$	(17	)
Foreign exchange		—
Ending balance at December 31, 2018	$	2

Contributions and Benefit Payments

Funding is based on actuarially-determined contributions and is limited to amounts that are currently deductible for tax purposes. Since funding calculations are based on different measurements than those used for accounting purposes, pension contributions are not equal to net periodic pension costs.

The following table sets forth our projected pension contributions to our qualified plans for fiscal year 2019, as well as the pension contributions to our qualified plans in fiscal years 2018 and 2017:

	2019 (Projected)		2018 (Actual)		2017 (Actual)
U.S.	$	60	$	50	$	50
U.K.	$	75	$	84	$	65
Other	$	23	$	14	$	13

Expected benefit payments from our defined benefit pension plans to current plan participants, including the effects of their expected future service, as appropriate, are as follows:

	Benefit Payments
Fiscal Year	U.S.		U.K.		Other		PRW		Total
2019	$	263	$	109	$	28	$	13	$	413
2020		250		107		25		10		392
2021		263		116		25		11		415
2022		272		119		26		11		428
2023		280		127		27		11		445
Years 2024 – 2028		1,435		735		160		60		2,390
	$	2,763	$	1,313	$	291	$	116	$	4,483

Defined Contribution Plan

We have defined contribution plans covering eligible employees in many countries. The most significant plans are in the U.S. and U.K. and are described here.

We have a U.S. defined contribution plan (the ‘Plan’) covering all eligible employees of Willis Towers Watson. The Plan allows participants to make pre-tax and Roth after-tax contributions and the Company provides a 100% match on the first 1% of employee contributions and a 50% match on the next 5% of employee contributions. Employees vest in the Company match upon 2 years of service. All investment assets of the plan are held in a trust account administered by independent trustees.

The Legacy Towers Watson U.K. pension plan has a money purchase component to which we make core contributions plus additional contributions matching those of the participants up to a maximum rate. Contribution rates depend on the age of the participant and whether or not they arise from salary sacrifice arrangements through which the participant has elected to receive a pension contribution in lieu of additional salary.

The Legacy Willis U.K. pension plan has a money purchase component to which we make core contributions plus additional contributions matching those of the participants up to a maximum rate. Contribution rates may arise from salary sacrifice arrangements through which the participant has elected to receive a pension contribution in lieu of additional salary.

We had defined contribution plan expense for the years ended December 31, 2018, 2017, and 2016 amounting to $150 million, $154 million and $152 million, respectively.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2018

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

Note 14 — Commitments and Contingencies

Leases

The Company leases certain land, buildings and equipment under various operating lease commitments. The total amount of the minimum rent is expensed on a straight-line basis over the term of the lease. Rental expenses and sub-lease rental income for operating leases are recorded as part of other operating expenses in the consolidated statements of comprehensive income. Rental expense, exclusive of sublease income, was $295 million, $302 million, and $302 million for the years ended December 31, 2018, 2017 and 2016, respectively. We have entered into sublease agreements for some of our excess leased space. Sublease income was $15 million, $21 million and $17 million for the years ended December 31, 2018, 2017 and 2016, respectively.

As of December 31, 2018, the aggregate future minimum rental commitments under all non-cancellable operating lease agreements are as follows:

	Gross rental commitments		Rentals from subleases			Net rental commitments
2019	$	197	$	(11	)	$	186
2020		180		(11	)		169
2021		159		(8	)		151
2022		142		(2	)		140
2023		131		(2	)		129
Thereafter		542		(8	)		534
Total	$	1,351	$	(42	)	$	1,309

At December 31, 2018 and 2017, the Company had certain capital lease obligations totaling $43 million and $48 million, respectively, primarily in respect of the Company’s Nashville property.

Guarantees

Guarantees issued by certain of Willis Towers Watson’s subsidiaries with respect to the senior notes and revolving credit facilities are discussed in Note 11 — Debt and Note 22 — Financial Information for Issuers and Other Guarantor Subsidiaries.

Certain of Willis Towers Watson’s subsidiaries have given the landlords of some leasehold properties occupied by the Company in the U.K. and the U.S. guarantees with respect to the performance of the lease obligations of the subsidiary holding the lease. The operating lease obligations subject to such guarantees amounted to $570 million and $669 million at December 31, 2018 and 2017, respectively. The capital lease obligations subject to such guarantees amounted to $7 million and $8 million at December 31, 2018 and 2017, respectively.

Acquisition liabilities

The Company has deferred and contingent consideration due to be paid on existing acquisitions until 2021 totaling $83 million at December 31, 2018. Most notably, our liabilities for the acquisitions of Alston Gayler and Miller Insurance Services LLP in December 2018 and May 2015, respectively, for which deferred and contingent consideration, including interest, was $73 million at December 31, 2018. Total deferred and contingent consideration paid during the year ended December 31, 2018 was $50 million.

Other contractual obligations

For certain subsidiaries and associates, the Company has the right to purchase shares (a call option) from co-shareholders at various dates in the future. In addition, the co-shareholders of certain subsidiaries and associates have the right to sell their shares (a put option) to the Company at various dates in the future. Generally, the exercise price of such put options and call options is formula-based (using revenue and earnings) and is designed to reflect fair value. Based on current projections of profitability and exchange rates, and assuming the put options are exercised, the potential amount payable from these options is not expected to exceed $33 million.

Additionally, the Company has capital commitments with Trident V Parallel Fund, LP, an investment fund managed by Stone Point Capital, and Dowling Capital Partners I, LP. At December 31, 2018, the Company is obligated to make capital contributions of approximately $2 million, collectively, to these funds.

Indemnification Agreements

Willis Towers Watson has various agreements which provide that it may be obligated to indemnify the other party to the agreement with respect to certain matters. Generally, these indemnification provisions are included in contracts arising in the normal course of business and in connection with the purchase and sale of certain businesses. Although it is not possible to predict the maximum potential amount of future payments that may become due under these indemnification agreements because of the conditional nature of the Company’s obligations and the unique facts of each particular agreement, we do not believe that any potential liability that may arise from such indemnity provisions is probable or material. There are no provisions for recourse to third parties, nor are any assets held by any third parties that any guarantor can liquidate to recover amounts paid under such indemnities.

Legal Proceedings

In the ordinary course of business, the Company is subject to various actual and potential claims, lawsuits and other proceedings. Some of the claims, lawsuits and other proceedings seek damages in amounts which could, if assessed, be significant. We do not expect the impact of claims or demands not described below to be material to the Company’s consolidated financial statements. The Company also receives subpoenas in the ordinary course of business and, from time to time, receives requests for information in connection with governmental investigations.

Errors and omissions claims, lawsuits, and other proceedings arising in the ordinary course of business are covered in part by professional indemnity or other appropriate insurance. See Note 15 — Supplementary Information for Certain Balance Sheet Accounts for the amounts accrued at December 31, 2018 and December 31, 2017 in the consolidated balance sheets. The terms of this insurance vary by policy year. Regarding self-insured risks, the Company has established provisions which are believed to be adequate in light of current information and legal advice, or, in certain cases, where a range of loss exists, the Company accrues the minimum amount in the range if no amount within the range is a better estimate than any other amount. The Company adjusts such provisions from time to time according to developments.

On the basis of current information, the Company does not expect that the actual claims, lawsuits and other proceedings to which the Company is subject, or potential claims, lawsuits, and other proceedings relating to matters of which it is aware, will ultimately have a material adverse effect on the Company’s financial condition, results of operations or liquidity. Nonetheless, given the large or indeterminate amounts sought in certain of these actions, and the inherent unpredictability of litigation and disputes with insurance companies, it is possible that an adverse outcome or settlement in certain matters could, from time to time, have a material adverse effect on the Company’s results of operations or cash flows in particular quarterly or annual periods. In addition, given the early stages of some litigation or regulatory proceedings described below, it is not possible to predict their outcome or resolution, and it is possible that these events may have a material adverse effect on the Company.

The Company provides for contingent liabilities based on ASC 450, Contingencies, when it is determined that a liability, inclusive of defense costs, is probable and reasonably estimable. The contingent liabilities recorded are primarily developed actuarially. Litigation is subject to many factors which are difficult to predict so there can be no assurance that in the event of a material unfavorable result in one or more claims, we will not incur material costs.

Merger-Related Securities Litigation

On November 21, 2017, a purported former stockholder of Legacy Towers Watson filed a putative class action complaint on behalf of a putative class consisting of all Legacy Towers Watson stockholders as of October 2, 2015 against the Company, Legacy Towers Watson, Legacy Willis, ValueAct Capital Management (‘ValueAct’), and certain current and former directors and officers of Legacy Towers Watson and Legacy Willis (John Haley, Dominic Casserley, and Jeffrey Ubben), in the United States District Court for the Eastern District of Virginia. The complaint asserted claims against certain defendants under Section 14(a) of the Securities Exchange Act of 1934 (the ‘Exchange Act’) for allegedly false and misleading statements in the proxy statement for the Merger; and against other defendants under Section 20(a) of the Exchange Act for alleged ‘control person’ liability with respect to such allegedly false and misleading statements. The complaint further contended that the allegedly false and misleading statements caused stockholders of Legacy Towers Watson to accept inadequate Merger consideration. The complaint sought damages in an unspecified amount. On February 20, 2018, the court appointed the Regents of the University of California (‘Regents’) as Lead Plaintiff and Bernstein Litowitz Berger & Grossman LLP (‘Bernstein’) as Lead Counsel for the putative class, consolidated all subsequently filed, removed, or transferred actions, and captioned the consolidated action ‘In re Willis Towers Watson plc Proxy Litigation,’ Master File No. 1:17-cv-1338-AJT-JFA. On March 9, 2018, Lead Plaintiff filed an Amended Complaint. On April 13, 2018, the defendants filed motions to dismiss the Amended Complaint, and, on July 11, 2018, following briefing and argument, the court granted the motions and dismissed the Amended Complaint in its entirety. On July 30, 2018, Lead Plaintiff filed a notice of appeal from the court’s July 11, 2018 dismissal order to the United States Court of Appeals for the Fourth Circuit, and, on December 6, 2018, the parties completed briefing on the appeal.

On February 27, 2018 and March 8, 2018, two additional purported former stockholders of Legacy Towers Watson, City of Fort Myers General Employees’ Pension Fund (‘Fort Myers’) and Alaska Laborers-Employers Retirement Trust (‘Alaska’), filed putative class action complaints on behalf of a putative class of Legacy Towers Watson stockholders against the former members of the Legacy Towers Watson board of directors, Legacy Towers Watson, Legacy Willis and ValueAct, in the Delaware Court of Chancery, captioned City of Fort Myers General Employees’ Pension Fund v. Towers Watson & Co., et al., C.A. No. 2018-0132, and Alaska Laborers-Employers Retirement Trust v. Victor F. Ganzi, et al., C.A. No. 2018-0155, respectively. Based on similar allegations as the Eastern District of Virginia action described above, the complaints assert claims against the former directors of Legacy Towers Watson for breach of fiduciary duty and against Legacy Willis and ValueAct for aiding and abetting breach of fiduciary duty.

On March 9, 2018, Regents filed a putative class action complaint on behalf of a putative class of Legacy Towers Watson stockholders against the Company, Legacy Willis, ValueAct, and Messrs. Haley, Casserley, and Ubben, in the Delaware Court of Chancery, captioned The Regents of the University of California v. John J. Haley, et al., C.A. No. 2018-0166. Based on similar allegations as the Eastern District of Virginia action described above, the complaint asserts claims against Mr. Haley for breach of fiduciary duty and against all other defendants for aiding and abetting breach of fiduciary duty. Also on March 9, 2018, Regents filed a motion for consolidation of all pending and subsequently filed Delaware Court of Chancery actions, and for appointment as Lead Plaintiff and for the appointment of Bernstein as Lead Counsel for the putative class. On March 29, 2018, Fort Myers and Alaska responded to Regents’ motion and cross-moved for appointment as Co-Lead Plaintiffs and for the appointment of their counsel, Grant & Eisenhofer P.A. and Kessler Topaz Meltzer & Check, LLP as Co-Lead Counsel. On April 2, 2018, the court consolidated the Delaware Court of Chancery actions and all related actions subsequently filed in or transferred to the Delaware Court of Chancery. On June 5, 2018, the court denied Regents’ motion for appointment of Lead Plaintiff and Lead Counsel and granted Fort Myers’ and Alaska’s cross-motion. On June 20, 2018, Fort Myers and Alaska designated the complaint previously filed by Alaska (the ‘Alaska Complaint’) as the operative complaint in the consolidated action. On September 14, 2018, the defendants filed motions to dismiss the Alaska Complaint. On October 31, 2018, Fort Myers and Alaska filed an amended complaint, which, based on similar allegations, asserts claims against the former directors of legacy Towers Watson for breach of fiduciary duty and against ValueAct and Mr. Ubben for aiding and abetting breach of fiduciary duty. On January 11, 2019, the defendants filed motions to dismiss the amended complaint.

On October 18, 2018, three additional purported former stockholders of Legacy Towers Watson, Naya Master Fund LP, Naya 174 Fund Limited and Naya Lincoln Park Master Fund Limited (collectively, ‘Naya’), filed a complaint against the Company, Legacy Towers Watson, Legacy Willis and John Haley, in the Supreme Court of the State of New York, County of New York, captioned Naya Master Fund LP, et al. v. John J. Haley, et al., Index No. 654968/2018. Based on similar allegations as the Eastern District of Virginia and Delaware actions described above, the complaint asserts claims for common law fraud and negligent misrepresentation. On December 18, 2018, the defendants filed a motion to dismiss the complaint.

The defendants dispute the allegations in these actions and intend to defend the lawsuits vigorously. Given the stage of the proceedings, the Company is unable to provide an estimate of the reasonably possible loss or range of loss in respect of the complaints.

Stanford Financial Group

The Company has been named as a defendant in 15 similar lawsuits relating to the collapse of The Stanford Financial Group (‘Stanford’), for which Willis of Colorado, Inc. acted as broker of record on certain lines of insurance. The complaints in these actions generally allege that the defendants actively and materially aided Stanford’s alleged fraud by providing Stanford with certain letters regarding coverage that they knew would be used to help retain or attract actual or prospective Stanford client investors. The complaints further allege that these letters, which contain statements about Stanford and the insurance policies that the defendants placed for Stanford, contained untruths and omitted material facts and were drafted in this manner to help Stanford promote and sell its allegedly fraudulent certificates of deposit.

The 15 actions are as follows:

•

Troice, et al. v. Willis of Colorado, Inc., et al., C.A. No. 3:9-CV-1274-N, was filed on July 2, 2009 in the U.S. District Court for the Northern District of Texas against Willis Group Holdings plc, Willis of Colorado, Inc. and a Willis associate, among others. On April 1, 2011, plaintiffs filed the operative Third Amended Class Action Complaint individually and on behalf of a putative, worldwide class of Stanford investors, adding Willis Limited as a defendant and alleging claims under Texas statutory and common law and seeking damages in excess of $1 billion, punitive damages and costs. On May 2, 2011, the defendants filed motions to dismiss the Third Amended Class Action Complaint, arguing, inter alia, that the plaintiffs’ claims are precluded by the Securities Litigation Uniform Standards Act of 1998 (‘SLUSA’).

On May 10, 2011, the court presiding over the Stanford-related actions in the Northern District of Texas entered an order providing that it would consider the applicability of SLUSA to the Stanford-related actions based on the decision in a separate Stanford action not involving a Willis entity, Roland v. Green, Civil Action No. 3:10-CV-0224-N (‘Roland’). On August 31, 2011, the court issued its decision in Roland, dismissing that action with prejudice under SLUSA.

On October 27, 2011, the court in Troice entered an order (i) dismissing with prejudice those claims asserted in the Third Amended Class Action Complaint on a class basis on the grounds set forth in the Roland decision discussed above and (ii) dismissing without prejudice those claims asserted in the Third Amended Class Action Complaint on an individual basis. Also on October 27, 2011, the court entered a final judgment in the action.

On October 28, 2011, the plaintiffs in Troice filed a notice of appeal to the U.S. Court of Appeals for the Fifth Circuit. Subsequently, Troice, Roland and a third action captioned Troice, et al. v. Proskauer Rose LLP, Civil Action No. 3:09-CV-01600-N, which also was dismissed on the grounds set forth in the Roland decision discussed above and on appeal to the U.S. Court of Appeals for the Fifth Circuit, were consolidated for purposes of briefing and oral argument. Following the completion of briefing and oral argument, on March 19, 2012, the Fifth Circuit reversed and remanded the actions. On April 2, 2012, the defendants-appellees filed petitions for rehearing en banc. On April 19, 2012, the petitions for rehearing en banc were denied. On July 18, 2012, defendants-appellees filed a petition for writ of certiorari with the United States Supreme Court regarding the Fifth Circuit’s reversal in Troice. On January 18, 2013, the Supreme Court granted our petition. Opening briefs were filed on May 3, 2013 and the Supreme Court heard oral argument on October 7, 2013. On February 26, 2014, the Supreme Court affirmed the Fifth Circuit’s decision.

On March 19, 2014, the plaintiffs in Troice filed a Motion to Defer Resolution of Motions to Dismiss, to Compel Rule 26(f) Conference and For Entry of Scheduling Order.

On March 25, 2014, the parties in Troice and the Janvey, et al. v. Willis of Colorado, Inc., et al. action discussed below stipulated to the consolidation of the two actions for pre-trial purposes under Rule 42(a) of the Federal Rules of Civil Procedure. On March 28, 2014, the Court ‘so ordered’ that stipulation and, thus, consolidated Troice and Janvey for pre-trial purposes under Rule 42(a).

On September 16, 2014, the court (a) denied the plaintiffs’ request to defer resolution of the defendants’ motions to dismiss, but granted the plaintiffs’ request to enter a scheduling order; (b) requested the submission of supplemental briefing by all parties on the defendants’ motions to dismiss, which the parties submitted on September 30, 2014; and (c) entered an order setting a schedule for briefing and discovery regarding plaintiffs’ motion for class certification, which schedule, among other things, provided for the submission of the plaintiffs’ motion for class certification (following the completion of briefing and discovery) on April 20, 2015.

On December 15, 2014, the court granted in part and denied in part the defendants’ motions to dismiss. On January 30, 2015, the defendants except Willis Group Holdings plc answered the Third Amended Class Action Complaint.

On April 20, 2015, the plaintiffs filed their motion for class certification, the defendants filed their opposition to plaintiffs’ motion, and the plaintiffs filed their reply in further support of the motion. Pursuant to an agreed stipulation also filed with the court on April 20, 2015, the defendants on June 4, 2015 filed sur-replies in further opposition to the motion. The Court has not yet scheduled a hearing on the motion.

On June 19, 2015, Willis Group Holdings plc filed a motion to dismiss the complaint for lack of personal jurisdiction. On November 17, 2015, Willis Group Holdings plc withdrew the motion.

On March 31, 2016, the parties in the Troice and Janvey actions entered into a settlement in principle that is described in more detail below.

•

Ranni v. Willis of Colorado, Inc., et al., C.A. No. 9-22085, was filed on July 17, 2009 against Willis Group Holdings plc and Willis of Colorado, Inc. in the U.S. District Court for the Southern District of Florida. The complaint was filed on behalf of a putative class of Venezuelan and other South American Stanford investors and alleges claims under Section 10(b) of the Securities Exchange Act of 1934 (and Rule 10b-5 thereunder) and Florida statutory and common law and seeks damages in an amount to be determined at trial. On October 6, 2009, Ranni was transferred, for consolidation or coordination with other Stanford-related actions (including Troice), to the Northern District of Texas by the U.S. Judicial Panel on Multidistrict Litigation (the ‘JPML’). The defendants have not yet responded to the complaint in Ranni. On August 26, 2014, the plaintiff filed a notice of voluntary dismissal of the action without prejudice.

•

Canabal, et al. v. Willis of Colorado, Inc., et al., C.A. No. 3:9-CV-1474-D, was filed on August 6, 2009 against Willis Group Holdings plc, Willis of Colorado, Inc. and the same Willis associate named as a defendant in Troice, among others, also in the Northern District of Texas. The complaint was filed individually and on behalf of a putative class of Venezuelan Stanford investors, alleged claims under Texas statutory and common law and sought damages in excess of $1 billion, punitive damages, attorneys’ fees and costs. On December 18, 2009, the parties in Troice and Canabal stipulated to the consolidation of those actions (under the Troice civil action number), and, on December 31, 2009, the plaintiffs in Canabal filed a notice of dismissal, dismissing the action without prejudice.

•

Rupert, et al. v. Winter, et al., Case No. 2009C115137, was filed on September 14, 2009 on behalf of 97 Stanford investors against Willis Group Holdings plc, Willis of Colorado, Inc. and the same Willis associate, among others, in Texas state court (Bexar County). The complaint alleges claims under the Securities Act of 1933, Texas and Colorado statutory law and Texas common law and seeks special, consequential and treble damages of more than $300 million, attorneys’ fees and costs. On October 20, 2009, certain defendants, including Willis of Colorado, Inc., (i) removed Rupert to the U.S. District Court for the Western District of Texas, (ii) notified the JPML of the pendency of this related action and (iii) moved to stay the action pending a determination by the JPML as to whether it should be transferred to the Northern District of Texas for consolidation or coordination with the other Stanford-related actions. On April 1, 2010, the JPML issued a final transfer order for the transfer of Rupert to the Northern District of Texas. On January 24, 2012, the court remanded Rupert to Texas state court (Bexar County), but stayed the action until further order of the court. On August 13, 2012, the plaintiffs filed a motion to lift the stay, which motion was denied by the court on September 16, 2014. On October 10, 2014, the plaintiffs appealed the court’s denial of their motion to lift the stay to the U.S. Court of Appeals for the Fifth Circuit. On January 5, 2015, the Fifth Circuit consolidated the appeal with the appeal in the Rishmague, et ano. v. Winter, et al. action discussed below, and the consolidated appeal, was fully briefed as of March 24, 2015. Oral argument on the consolidated appeal was held on September 2, 2015. On September 16, 2015, the Fifth Circuit affirmed. The defendants have not yet responded to the complaint in Rupert.

•

Casanova, et al. v. Willis of Colorado, Inc., et al., C.A. No. 3:10-CV-1862-O, was filed on September 16, 2010 on behalf of seven Stanford investors against Willis Group Holdings plc, Willis Limited, Willis of Colorado, Inc. and the same Willis associate, among others, also in the Northern District of Texas. The complaint alleges claims under Texas statutory and common law and seeks actual damages in excess of $5 million, punitive damages, attorneys’ fees and costs. On February 13, 2015, the parties filed an Agreed Motion for Partial Dismissal pursuant to which they agreed to the dismissal of certain claims pursuant to the motion to dismiss decisions in the Troice action discussed above and the Janvey action discussed below. Also on February 13, 2015, the defendants except Willis Group Holdings plc answered the complaint in the Casanova action. On June 19, 2015, Willis Group Holdings plc filed a motion to dismiss the complaint for lack of personal jurisdiction. Plaintiffs have not opposed the motion.

•

Rishmague, et ano. v. Winter, et al., Case No. 2011CI2585, was filed on March 11, 2011 on behalf of two Stanford investors, individually and as representatives of certain trusts, against Willis Group Holdings plc, Willis of Colorado, Inc., Willis of Texas, Inc. and the same Willis associate, among others, in Texas state court (Bexar County). The complaint alleges claims under Texas and Colorado statutory law and Texas common law and seeks special, consequential and treble damages of more than $37 million and attorneys’ fees and costs. On April 11, 2011, certain defendants, including Willis of Colorado, Inc., (i) removed Rishmague to the Western District of Texas, (ii) notified the JPML of the pendency of this related action and (iii) moved to stay the action pending a determination by the JPML as to whether it should be transferred to the Northern District of Texas for consolidation or coordination with the other Stanford-related actions. On August 8, 2011, the JPML issued a final transfer order for the transfer of Rishmague to the Northern District of Texas, where it is currently pending. On August 13, 2012, the plaintiffs joined with the plaintiffs in the Rupert action in their motion to lift the court’s stay of the Rupert action. On September 9, 2014, the court remanded Rishmague to Texas state court (Bexar County), but stayed the action until further order of the court and denied the plaintiffs’ motion to lift the stay. On October 10, 2014, the plaintiffs appealed the court’s denial of their motion to lift the stay to the Fifth Circuit. On January 5, 2015, the Fifth Circuit consolidated the appeal with the appeal in the Rupert action, and the consolidated appeal was fully briefed as of March 24, 2015. Oral argument on the consolidated appeal was held on September 2, 2015. On September 16, 2015, the Fifth Circuit affirmed. The defendants have not yet responded to the complaint in Rishmague.

•

MacArthur v. Winter, et al., Case No. 2013-07840, was filed on February 8, 2013 on behalf of two Stanford investors against Willis Group Holdings plc, Willis of Colorado, Inc., Willis of Texas, Inc. and the same Willis associate, among others, in Texas state court (Harris County). The complaint alleges claims under Texas and Colorado statutory law and Texas common law and seeks actual, special, consequential and treble damages of approximately $4 million and attorneys’ fees and costs. On March 29, 2013, Willis of Colorado, Inc. and Willis of Texas, Inc. (i) removed MacArthur to the U.S. District Court for the Southern District of Texas and (ii) notified the JPML of the pendency of this related action. On April 2, 2013, Willis of Colorado, Inc. and Willis of Texas, Inc. filed a motion in the Southern District of Texas to stay the action pending a determination by the JPML as to whether it should be transferred to the Northern District of Texas for consolidation or coordination with the other Stanford-related actions. Also on April 2, 2013, the court presiding over MacArthur in the Southern District of Texas transferred the action to the Northern District of Texas for consolidation or coordination with the other Stanford-related actions. On September 29, 2014, the parties stipulated to the remand (to Texas state court (Harris County)) and stay of MacArthur until further order of the court (in accordance with the court’s September 9, 2014 decision in Rishmague (discussed above)), which stipulation was ‘so ordered’ by the court on October 14, 2014. The defendants have not yet responded to the complaint in MacArthur.

•

Florida suits: On February 14, 2013, five lawsuits were filed against Willis Group Holdings plc, Willis Limited and Willis of Colorado, Inc. in Florida state court (Miami-Dade County), alleging violations of Florida common law. The five suits are: (1) Barbar, et al. v. Willis Group Holdings Public Limited Company, et al., Case No. 13-05666CA27, filed on behalf of 35 Stanford investors seeking compensatory damages in excess of $30 million; (2) de Gadala-Maria, et al. v. Willis Group Holdings Public Limited Company, et al., Case No. 13-05669CA30, filed on behalf of 64 Stanford investors seeking compensatory damages in excess of $83.5 million; (3) Ranni, et ano. v. Willis Group Holdings Public Limited Company, et al., Case No. 13-05673CA06, filed on behalf of two Stanford investors seeking compensatory damages in excess of $3 million; (4) Tisminesky, et al. v. Willis Group Holdings Public Limited Company, et al., Case No. 13-05676CA09, filed on behalf of 11 Stanford investors seeking compensatory damages in excess of $6.5 million; and (5) Zacarias, et al. v. Willis Group Holdings Public Limited Company, et al., Case No. 13-05678CA11, filed on behalf of 10 Stanford investors seeking compensatory damages in excess of $12.5 million. On June 3, 2013, Willis of Colorado, Inc. removed all five cases to the Southern District of Florida and, on June 4, 2013, notified the JPML of the pendency of these related actions. On June 10, 2013, the court in Tisminesky issued an order sua sponte staying and administratively closing that action pending a determination by the JPML as to whether it should be transferred to the Northern District of Texas for consolidation and coordination with the other Stanford-related actions. On June 11, 2013, Willis of Colorado, Inc. moved to stay the other four actions pending the JPML’s transfer decision. On June 20, 2013, the JPML issued a conditional transfer order for the transfer of the five actions to the Northern District of Texas, the transmittal of which was stayed for seven days to allow for any opposition to be filed. On June 28, 2013, with no opposition having been filed, the JPML lifted the stay, enabling the transfer to go forward.

On September 30, 2014, the court denied the plaintiffs’ motion to remand in Zacarias, and, on October 3, 2014, the court denied the plaintiffs’ motions to remand in Tisminesky and de Gadala Maria. On December 3, 2014 and March 3, 2015, the court granted the plaintiffs’ motions to remand in Barbar and Ranni, respectively, remanded both actions to Florida state court (Miami-Dade County) and stayed both actions until further order of the court. On January 2, 2015 and April 1, 2015, the plaintiffs in Barbar and Ranni, respectively, appealed the court’s December 3, 2014 and March 3, 2015 decisions to the Fifth Circuit. On April 22, 2015 and July 22, 2015, respectively, the Fifth Circuit dismissed the Barbar and Ranni appeals sua sponte for lack of jurisdiction. The defendants have not yet responded to the complaints in Ranni or Barbar.

On April 1, 2015, the defendants except Willis Group Holdings plc filed motions to dismiss the complaints in Zacarias, Tisminesky and de Gadala-Maria. On June 19, 2015, Willis Group Holdings plc filed motions to dismiss the complaints in Zacarias, Tisminesky and de Gadala-Maria for lack of personal jurisdiction. On July 15, 2015, the court dismissed the complaint in Zacarias in its entirety with leave to replead within 21 days. On July 21, 2015, the court dismissed the complaints in Tisminesky and de Gadala-Maria in their entirety with leave to replead within 21 days. On August 6, 2015, the plaintiffs in Zacarias, Tisminesky and de Gadala-Maria filed amended complaints (in which, among other things, Willis Group Holdings plc was no longer named as a defendant). On September 11, 2015, the defendants filed motions to dismiss the amended complaints. The motions await disposition by the court.

•

Janvey, et al. v. Willis of Colorado, Inc., et al., Case No. 3:13-CV-03980-D, was filed on October 1, 2013 also in the Northern District of Texas against Willis Group Holdings plc, Willis Limited, Willis North America Inc., Willis of Colorado, Inc. and the same Willis associate. The complaint was filed (i) by Ralph S. Janvey, in his capacity as Court-Appointed Receiver for the Stanford Receivership Estate, and the Official Stanford Investors Committee (the ‘OSIC’) against all defendants and (ii) on behalf of a putative, worldwide class of Stanford investors against Willis North America Inc. Plaintiffs Janvey and the OSIC allege claims under Texas common law and the court’s Amended Order Appointing Receiver, and the putative class plaintiffs allege claims under Texas statutory and common law. Plaintiffs seek actual damages in excess of $1 billion, punitive damages and costs. As alleged by the Stanford Receiver, the total amount of collective losses allegedly sustained by all investors in Stanford certificates of deposit is approximately $4.6 billion.

On November 15, 2013, plaintiffs in Janvey filed the operative First Amended Complaint, which added certain defendants unaffiliated with Willis. On February 28, 2014, the defendants filed motions to dismiss the First Amended Complaint, which motions, other than with respect to Willis Group Holding plc’s motion to dismiss for lack of personal jurisdiction, were granted in part and denied in part by the court on December 5, 2014. On December 22, 2014, Willis filed a motion to amend the court’s December 5 order to certify an interlocutory appeal to the Fifth Circuit, and, on December 23, 2014, Willis filed a motion to amend and, to the extent necessary, reconsider the court’s December 5 order. On January 16, 2015, the defendants answered the First Amended Complaint. On January 28, 2015, the court denied Willis’s motion to amend the court’s December 5 order to certify an interlocutory appeal to the Fifth Circuit. On February 4, 2015, the court granted Willis’s motion to amend and, to the extent necessary, reconsider the December 5 order.

As discussed above, on March 25, 2014, the parties in Troice and Janvey stipulated to the consolidation of the two actions for pre-trial purposes under Rule 42(a) of the Federal Rules of Civil Procedure. On March 28, 2014, the Court ‘so ordered’ that stipulation and, thus, consolidated Troice and Janvey for pre-trial purposes under Rule 42(a).

On January 26, 2015, the court entered an order setting a schedule for briefing and discovery regarding the plaintiffs’ motion for class certification, which schedule, among other things, provided for the submission of the plaintiffs’ motion for class certification (following the completion of briefing and discovery) on July 20, 2015. By letter dated March 4, 2015, the parties requested that the court consolidate the scheduling orders entered in Troice and Janvey to provide for a class certification submission date of April 20, 2015 in both cases. On March 6, 2015, the court entered an order consolidating the scheduling orders in Troice and Janvey, providing for a class certification submission date of April 20, 2015 in both cases, and vacating the July 20, 2015 class certification submission date in the original Janvey scheduling order.

On November 17, 2015, Willis Group Holdings plc withdrew its motion to dismiss for lack of personal jurisdiction.

On March 31, 2016, the parties in the Troice and Janvey actions entered into a settlement in principle that is described in more detail below.

•

Martin v. Willis of Colorado, Inc., et al., Case No. 201652115, was filed on August 5, 2016, on behalf of one Stanford investor against Willis Group Holdings plc, Willis Limited, Willis of Colorado, Inc. and the same Willis associate in Texas state court (Harris County). The complaint alleges claims under Texas statutory and common law and seeks actual damages of less than $100,000, exemplary damages, attorneys’ fees and costs. On September 12, 2016, the plaintiff filed an amended complaint, which added five more Stanford investors as plaintiffs and seeks damages in excess of $1 million. The defendants have not yet responded to the amended complaint in Martin.

•

Abel, et al. v. Willis of Colorado, Inc., et al., C.A. No. 3:16-cv-2601, was filed on September 12, 2016, on behalf of more than 300 Stanford investors against Willis Group Holdings plc, Willis Limited, Willis of Colorado, Inc. and the same Willis associate, also in the Northern District of Texas. The complaint alleges claims under Texas statutory and common law and seeks actual damages in excess of $135 million, exemplary damages, attorneys’ fees and costs. On November 10, 2016, the plaintiffs filed an amended complaint, which, among other things, added several more Stanford investors as plaintiffs. The defendants have not yet responded to the complaint in Abel.

The plaintiffs in Janvey and Troice and the other actions above seek overlapping damages, representing either the entirety or a portion of the total alleged collective losses incurred by investors in Stanford certificates of deposit, notwithstanding the fact that Legacy Willis acted as broker of record for only a portion of time that Stanford issued certificates of deposit. In the fourth quarter of 2015, the Company recognized a $70 million litigation provision for loss contingencies relating to the Stanford matters based on its ongoing review of a variety of factors as required by accounting standards.

On March 31, 2016, the Company entered into a settlement in principle for $120 million relating to this litigation, and increased its provisions by $50 million during that quarter. Further details on this settlement in principle are given below.

The settlement is contingent on a number of conditions, including court approval of the settlement and a bar order prohibiting any continued or future litigation against Willis related to Stanford, which may not be given. Therefore, the ultimate resolution of these matters may differ from the amount provided for. The Company continues to dispute the allegations and, to the extent litigation proceeds, to defend the lawsuits vigorously.

Settlement. On March 31, 2016, the Company entered into a settlement in principle, as reflected in a Settlement Term Sheet, relating to the Stanford litigation matter. The Company agreed to the Settlement Term Sheet to eliminate the distraction, burden, expense and uncertainty of further litigation. In particular, the settlement and the related bar orders described below, if upheld through any appeals, would enable the Company (a newly-combined firm) to conduct itself with the bar orders’ protection from the continued overhang of matters alleged to have occurred approximately a decade ago. Further, the Settlement Term Sheet provided that the parties understood and agreed that there is no admission of liability or wrongdoing by the Company. The Company expressly denies any liability or wrongdoing with respect to the matters alleged in the Stanford litigation.

On or about August 31, 2016, the parties to the settlement signed a formal Settlement Agreement memorializing the terms of the settlement as originally set forth in the Settlement Term Sheet. The parties to the Settlement Agreement are Ralph S. Janvey (in his capacity as the Court-appointed receiver (the ‘Receiver’) for The Stanford Financial Group and its affiliated entities in receivership (collectively, ‘Stanford’)), the Official Stanford Investors Committee, Samuel Troice, Martha Diaz, Paula Gilly-Flores, Punga Punga Financial, Ltd., Manuel Canabal, Daniel Gomez Ferreiro and Promotora Villa Marina, C.A. (collectively, ‘Plaintiffs’), on the one hand, and Willis Towers Watson Public Limited Company (formerly Willis Group Holdings Public Limited Company), Willis Limited, Willis North America Inc., Willis of Colorado, Inc. and the Willis associate referenced above (collectively, ‘Defendants’), on the other hand. Under the terms of the Settlement Agreement, the parties agreed to settle and dismiss the Janvey and Troice actions (collectively, the ‘Actions’) and all current or future claims arising from or related to Stanford in exchange for a one-time cash payment to the Receiver by the Company of $120 million to be distributed to all Stanford investors who have claims recognized by the Receiver pursuant to the distribution plan in place at the time the payment is made.

The Settlement Agreement also provides the parties’ agreement to seek the Court’s entry of bar orders prohibiting any continued or future litigation against the Defendants and their related parties of claims relating to Stanford, whether asserted to date or not. The terms of the bar orders therefore would prohibit all Stanford-related litigation described above, and not just the Actions, but including any pending matters and any actions that may be brought in the future. Final Court approval of these bar orders is a condition of the settlement.

On September 7, 2016, Plaintiffs filed with the Court a motion to approve the settlement. On October 19, 2016, the Court preliminarily approved the settlement. Several of the plaintiffs in the other actions above objected to the settlement, and a hearing to consider final approval of the settlement was held on January 20, 2017, after which the Court reserved decision. On August 23, 2017, the Court approved the settlement, including the bar orders. Several of the objectors appealed the settlement approval and bar orders to the Fifth Circuit. The briefing related to the appeals is now completed and oral argument on the appeals was heard on December 3, 2018. There is no date certain for when the appeals will be decided.

The Company will not make the $120 million settlement payment unless and until the appeals are decided in its favor and the settlement is not subject to any further appeal.

City of Houston

On August 1, 2014, the City of Houston (‘plaintiff’) filed suit against Legacy Towers Watson in the United States District Court for the Southern District of Texas, Houston Division. On March 8, 2016, plaintiff filed its First Amended Complaint.

In the amended complaint, plaintiff alleged various deficiencies in pension actuarial work-product and advice stated to have been provided by Legacy Towers Watson’s predecessor firm, Towers Perrin, in its capacity as principal actuary to the Houston Firefighters’ Relief and Retirement Fund (the ‘Fund’). Towers Perrin is stated to have acted in this capacity between ‘the early 1980s until 2003.’

In particular, the amended complaint alleged ‘misrepresentations and miscalculations’ in valuation reports allegedly issued by Towers Perrin from 2000 through 2002 upon which plaintiff claimed to have relied. Plaintiff asserted that Towers Perrin assigned a new team of actuaries to the Fund in 2002 ‘to correct Towers’ own earlier mistakes’ and that the new team ‘altered’ certain calculations which ‘increased the actuarial accrued liability by $163 million.’ Plaintiff claimed that the reports indicated that the City’s minimum contribution percentages to the Fund would remain in place through at least 2019 and that existing benefits under the Fund could be increased, and new benefits could be added, without increasing plaintiff’s financial burden, and without increasing plaintiff’s rate of annual contributions to the Fund. The amended complaint alleged that plaintiff relied on these reports when supporting a new benefits package for the Fund. These reports, and other advice, were alleged, among other things, to have been negligent, to have misrepresented the present and future financial condition of the Fund and the contributions required to be made by plaintiff to support those benefits. Plaintiff asserted that, but for Towers Perrin’s alleged negligence and misrepresentations, plaintiff would not have supported the benefits increase, and that such increased benefits would not and could not have been approved or enacted. It is further asserted that Towers Perrin’s alleged ‘negligence and misrepresentations damaged the City in the amount of tens of millions of dollars in annual contributions.’ The amended complaint sought the award of punitive damages, actual damages, exemplary damages, special damages, attorney’s fees and expenses, costs of suit, pre- and post- judgment interest at the maximum legal rate, and other unspecified legal and equitable relief.

On October 10, 2014, Legacy Towers Watson filed a motion to dismiss plaintiff’s entire complaint on the basis that the complaint fails to state a claim upon which relief can be granted. On November 21, 2014, the City filed its response in opposition to Legacy Towers Watson’s motion to dismiss. On September 23, 2015, Legacy Towers Watson’s motion to dismiss was denied by the United States District Court for the Southern District of Texas, Houston Division. The court entered a Scheduling Order setting trial for May 30, 2017. On June 20, 2016, the Court entered a Second Amended Scheduling Order setting trial for October 31, 2017. On March 27, 2017, the Court entered a Third Amended Scheduling Order setting trial for January 16, 2018.

On May 8, 2017, Legacy Towers Watson received the City’s expert’s damages report, which asserted the City had incurred actual damages of approximately $430 million through July 1, 2017, and would incur future damages that have a present value of approximately $400 million as of July 1, 2017 if the Fund pension benefits remained unchanged. On June 30, 2017, Legacy Towers Watson served its expert reports in rebuttal to the City’s expert reports. Legacy Towers Watson’s experts concluded that Legacy Towers Watson’s work was reasonable and conformed with the actuarial standards of practice, and that Legacy Towers Watson did not cause any damages to the City. Legacy Towers Watson’s experts also concluded that the City’s damages model is flawed.

On January 9, 2018, Legacy Towers Watson and the City participated in a mediation and reached a settlement in principle. On April 4, 2018, the City of Houston City Council approved the settlement. On April 13, 2018, the court entered an order dismissing the case with prejudice, and the settlement became effective on that date. The settlement provided that in exchange for a dismissal of the claims of the City related to Legacy Towers Watson’s pension actuarial advice to the Fund, and any potential claims the City may have related to Legacy Towers Watson’s pension actuarial advice to the Houston Municipal Employees Pension System and the Houston Police Officers Pension System, Legacy Towers Watson agreed to pay a total of $40 million, which was paid in full in April 2018. The Company accrued its portion of the settlement prior to 2018.

Elma Sanchez, et. al

On August 6, 2013, three individual plaintiffs filed a putative class action suit against the California Public Employees’ Retirement System (‘CalPERS’) in Los Angeles County Superior Court. On January 10, 2014, plaintiffs filed an amended complaint, which added as defendants several members of CalPERS’ Board of Administration and three Legacy Towers Watson entities, Towers Watson & Co., Towers Perrin, and Tillinghast-Towers Perrin (‘Towers Perrin’).

Plaintiffs’ claims all relate to a self-funded, non-profit Long Term Care Program that CalPERS established in 1995 (the ‘LTC Program’). Plaintiffs’ claims seek unspecified damages allegedly resulting from CalPERS’ 2012 decision to implement in 2015 and 2016 an 85 percent increase in the premium rates of certain of the long term care policies it issued between 1995 and 2004 (the ‘85% Increase’).

The amended complaint alleges claims against CalPERS for breach of contract and breach of fiduciary duty. It also includes a single cause of action against Towers Perrin for professional negligence relating to actuarial services Towers Perrin provided to CalPERS relating to the LTC Program between 1995 and 2004.

Plaintiffs principally allege that CalPERS mismanaged the LTC Program and its investment assets in multiple respects and breached its contractual and fiduciary duties to plaintiffs and other class members by impermissibly imposing the 85% Increase to make up for investment losses. Plaintiffs also allege that Towers Perrin recommended inadequate initial premium rates at the outset of the LTC Program and used unspecified inappropriate assumptions in its annual valuations for CalPERS. Plaintiffs claim that Towers Perrin’s allegedly negligent acts and omissions, prior to the end of its retainer in 2004, contributed to the need for the 85% Increase.

In May 2014, the court denied the motions to dismiss filed by CalPERS and Towers Perrin addressed to the sufficiency of the complaint. On January 28, 2016, the court granted plaintiffs’ motion for class certification. The certified class as currently defined includes those long term care policy holders whose policies were ‘subject to’ the 85% Increase. The court thereafter set an October 2, 2017 trial date.

In May 2016, the case was reassigned to a different judge. The court agreed that Towers Perrin may file a motion for summary judgment which was initially scheduled to be heard on February 3, 2017. The motion was then fully briefed, and the hearing date was thereafter moved to March 8, 2017.

On March 1, 2017, Towers Perrin and Plaintiffs participated in a mediation and reached a settlement in principle. Pursuant to the settlement in principle, in exchange for a dismissal of the claims of all class members and a release of Towers Perrin by all class members, Towers Perrin would pay a total of $9.75 million into an interest-bearing settlement fund, to be used to reimburse class counsel's costs, and for later distribution to class members as approved by the Court. This proposed settlement amount was accrued during the three months ended March 31, 2017. At the hearing on final approval held on January 26, 2018, the Court granted final approval of the settlement. Class members who properly objected to the settlement had standing to appeal by April 9, 2018. No class members filed an appeal and, therefore, the judgment is now final.

The settlement amount of $9.75 million was paid on June 5, 2018.

Aviation Broking Competition Investigations

In April 2017, the Financial Conduct Authority (‘FCA’) informed Willis Limited, our U.K. broking subsidiary, that it had opened a formal investigation into possible agreements/concerted practices in the aviation broking sector.

In October 2017, the European Commission (‘Commission’) disclosed to us that it has initiated civil investigation proceedings in respect of a suspected infringement of E.U. competition rules involving several broking firms, including our principal U.K. broking subsidiary and one of its parent entities. In particular, the Commission has stated that the civil proceedings concern the exchange of commercially sensitive information between competitors in relation to aviation and aerospace insurance and reinsurance broking products and services in the European Economic Area, as well as possible coordination between competitors. The initiation of proceedings does not mean there has been a finding of infringement, merely that the Commission will investigate the case. We are providing information to the Commission as requested.

When the Commission initiated these proceedings, the FCA closed its related competition investigation, but still retained jurisdiction over broking regulatory matters arising from this conduct. In early 2018, the FCA advised that it will not be taking enforcement action against Willis Limited in connection with any such broking regulatory matters.

In May 2018, the Korea Fair Trade Commission (‘KFTC’) disclosed to us that it is investigating alleged cartels in the insurance broking industry. The KFTC has since requested information related to, among other topics, the aviation and aerospace insurance brokerage market and exchanges of information between brokers about insurance policies.

In January 2019, the Brazil Conselho Administrativo de Defesa Economica (‘CADE’) launched an administrative proceeding to investigate alleged sharing of competitive and commercially sensitive information in the insurance and reinsurance brokerage industry for aviation and aerospace and related ancillary services. The CADE identified 11 entities under investigation, including Willis Group Limited, one of our U.K. subsidiaries.

Given the status of these investigations, the Company is currently unable to assess the terms on which they will be resolved, or any other regulatory matter or civil claims emanating from the conduct being investigated, will be resolved, and thus is unable to provide an estimate of the reasonably possible loss or range of loss.

U.K. Investment Consulting Investigation

In September 2017, the FCA announced that it would make a referral with respect to the investment consulting industry to the U.K. Competition & Markets Authority (the ‘CMA’). The CMA then commenced a market investigation, and the Company is currently cooperating with the investigation.

The CMA released its final report on December 12, 2018, finding that there is an adverse effect on competition. To address these findings, the CMA has proposed certain remedies, including mandatory tendering when trustees first purchase fiduciary management services, the reporting of investment performance to customers using a set of common standards, transparency in reporting of fees in fiduciary management and the expansion of the FCA’s regulatory perimeter to include the main activities of investment consultancy and fiduciary management providers. The Company is generally supportive of these proposed remedies. The CMA will implement the remedies by way of an order on pension scheme trustees and firms providing the relevant services. Before finalizing the order, the CMA will consult with all interested parties until March 13, 2019 on the details of the order. The remedies are expected to be effective later in 2019.

London Wholesale Insurance Broker Market Study

In November 2017, the FCA published its Terms of Reference for its Market Study into insurance broking activities in the London Wholesale Market including market power, conflicts of interest and broker conduct. This was an industry-wide inquiry and not particular to the Company. The FCA used its powers under the UK Financial Services and Markets Act 2000 to collate information and originally aimed to issue an interim report in or about the first quarter of 2019. The Study had been expected to take two years to conclude. Two of the Company’s subsidiaries responded to extensive data requests which had phased response times through May 2018. It was possible that outcomes of the Study could include new rules, changes to market practices, referral to the U.K. Competition & Markets Authority for a market investigation, and/or individual firm investigations on specific issues. On February 20, 2019, the FCA published its report in final form and closed its study, finding amongst other things that it had ‘not found evidence of significant levels of harm to competition that require intrusive remedies’. The FCA also said it planned to continue to monitor the market as part of its normal supervision function, including in relation to broker business models and the effectiveness of competition. It also said it planned to engage with individual firms on a number of related issues and would continue to assess specific firms’ compliance with regulatory obligations, including conflict of interest, as part of its normal supervisory function.

Supplementary Information for Certain Balance Sheet Accounts Supplementary Information for Certain Balance Sheet Accounts (Notes)

12 Months Ended

Dec. 31, 2018

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Supplemental Balance Sheet Disclosures

Note 15 — Supplementary Information for Certain Balance Sheet Accounts

Additional details of specific balance sheet accounts are detailed below.

Prepaid and other current assets consist of the following:

	December 31, 2018		December 31, 2017
Prepayments and accrued income	$	136	$	132
Deferred contract costs		102		—
Derivatives and investments		25		29
Deferred compensation plan assets		18		21
Retention incentives		5		7
Corporate income and other taxes		61		170
Other current assets		57		71
Total prepaid and other current assets	$	404	$	430

Other non-current assets consist of the following:

	December 31, 2018		December 31, 2017
Prepayments and accrued income	$	14	$	18
Deferred contract costs		46		—
Deferred compensation plan assets		125		135
Deferred tax assets		59		46
Accounts receivable, net		20		33
Other investments		7		26
Other non-current assets		196		189
Total other non-current assets	$	467	$	447

Deferred revenue and accrued expenses consist of the following:

	December 31, 2018		December 31, 2017
Accounts payable, accrued liabilities and deferred income	$	691	$	772
Discretionary compensation		321		313
Accrued compensation		437		439
Accrued vacation		111		93
Other employee-related liabilities		87		94
Total deferred revenue and accrued expenses	$	1,647	$	1,711

Other current liabilities consist of the following:

	December 31, 2018		December 31, 2017
Accounts payable	$	163	$	136
Income and other taxes payable		129		90
Contingent and deferred consideration on acquisitions		61		55
Payroll-related liabilities		210		209
Derivatives		13		32
Third party commissions		169		172
Other current liabilities		119		110
Total other current liabilities	$	864	$	804

Provision for liabilities consists of the following:

	December 31, 2018		December 31, 2017
Claims, lawsuits and other proceedings	$	455	$	474
Other provisions		85		84
Total provision for liabilities	$	540	$	558

Other non-current liabilities consist of the following:

	December 31, 2018		December 31, 2017
Incentives from lessors	$	120	$	138
Deferred compensation plan liability		125		135
Contingent and deferred consideration on acquisitions		22		41
Liabilities for uncertain tax positions		46		60
Lease-related liabilities		29		28
Other non-current liabilities		87		142
Total other non-current liabilities	$	429	$	544

Other Income, Net

12 Months Ended

Dec. 31, 2018

Other Income And Expenses [Abstract]

Other Income, Net

Note 16 — Other Income, Net

Other income, net consists of the following:

	Years ended December 31,
	2018			2017			2016
(Loss)/gain on disposal of operations	$	(9	)	$	13		$	2
Net periodic pension and postretirement benefit credits ⁽ⁱ⁾		280			222			203
Interest in earnings of associates ⁽ⁱⁱ⁾		3			3			2
Impact of Venezuelan currency devaluation		—			(2	)		—
Foreign exchange loss		(24	)		(72	)		(29	)
Other income, net	$	250		$	164		$	178

(i)

As a result of the retrospective adoption of ASU 2017-07 within the consolidated statements of comprehensive income, the service-cost component of net periodic benefit (income)/cost remained within salaries and benefits expense, while the remainder of the components are now included within other income, net. See Note 2 — Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements for further details.

(ii)	Beginning in 2018, the Company retrospectively reclassified the pre-tax effect of its interest in earnings of associates from its own line item to other income, net within its consolidated statements of comprehensive income.

Accumulated Other Comprehensive Loss

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

Accumulated Other Comprehensive Loss

Note 17 — Accumulated Other Comprehensive Loss

The components of other comprehensive (loss)/income are as follows:

	December 31, 2018									December 31, 2017									December 31, 2016
	Before tax amount			Tax			Net of tax amount			Before tax amount			Tax			Net of tax amount			Before tax amount			Tax		Net of tax amount
Other comprehensive (loss)/income:
Foreign currency translation	$	(251	)	$	—		$	(251	)	$	295		$	—		$	295		$	(353	)	$	—	$	(353	)
Defined pension and post-retirement benefits		(258	)		59			(199	)		3			11			14			(553	)		114		(439	)
Derivative instruments		5			(3	)		2			90			(15	)		75			(87	)		12		(75	)
Other comprehensive (loss)/income		(504	)		56			(448	)		388			(4	)		384			(993	)		126		(867	)
Less: Other comprehensive (income)/loss attributable to non-controlling interests		—			—			—			(13	)		—			(13	)		20			—		20
Other comprehensive (loss)/income attributable to Willis Towers Watson	$	(504	)	$	56		$	(448	)	$	375		$	(4	)	$	371		$	(973	)	$	126	$	(847	)

Changes in the components of accumulated other comprehensive loss, net of tax, are included in the following table. This table excludes amounts attributable to non-controlling interests, which are not material for further disclosure.

	Foreign currency translation ⁽ⁱ⁾			Cash flow hedges ⁽ⁱ⁾			Defined pension and post- retirement benefit costs ⁽ⁱⁱ⁾			Total
Balance, January 1, 2016	$	(314	)	$	(10	)	$	(713	)	$	(1,037	)
Other comprehensive loss before reclassifications		(336	)		(110	)		(483	)		(929	)
Loss reclassified from accumulated other comprehensive loss (net of income tax benefit of $5)		—			38			44			82
Net other comprehensive loss		(336	)		(72	)		(439	)		(847	)
Balance, December 31, 2016	$	(650	)	$	(82	)	$	(1,152	)	$	(1,884	)
Other comprehensive income/(loss) before reclassifications		285			28			(26	)		287
Loss reclassified from accumulated other comprehensive loss (net of income tax benefit of $18)		—			44			40			84
Net other comprehensive income		285			72			14			371
Balance, December 31, 2017	$	(365	)	$	(10	)	$	(1,138	)	$	(1,513	)
Other comprehensive income/(loss) before reclassifications		(251	)		(22	)		(241	)		(514	)
Loss reclassified from accumulated other comprehensive loss (net of income tax benefit of $17)		—			24			42			66
Net other comprehensive loss		(251	)		2			(199	)		(448	)
Balance, December 31, 2018	$	(616	)	$	(8	)	$	(1,337	)	$	(1,961	)

(i)

Reclassification adjustments from accumulated other comprehensive loss related to foreign currency translation and cash flow hedges are included in Other income, net in the accompanying consolidated statements of comprehensive income. See Note 10 — Derivative Financial Instruments for additional details regarding the reclassification adjustments for the hedge settlements.

(ii)	Reclassification adjustments from accumulated other comprehensive loss are included in the computation of net periodic pension cost (see Note 13 — Retirement Benefits). These components are included in Other income, net in the accompanying consolidated statements of comprehensive income.

Share-Based Compensation

12 Months Ended

Dec. 31, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Share-Based Compensation

Note 18 — Share-based Compensation

Plan Summaries

On December 31, 2018, the Company had a number of open share-based compensation plans, which provide for the grant of time-based and performance-based options, time-based and performance-based restricted stock units, and various other share-based grants to employees. All of the Company’s share-based compensation plans under which any options, restricted stock units (‘RSUs’) or other share-based grants are outstanding as of December 31, 2018 are described below. The compensation cost that has been recognized for these plans for the years ended December 31, 2018, 2017 and 2016 was $50 million, $67 million and $123 million, respectively. The total income tax benefits recognized in the consolidated statements of comprehensive income for share-based compensation arrangements for the years ended December 31, 2018, 2017, and 2016 were $10 million, $22 million and $35 million, respectively.

2012 Equity Incentive Plan

This plan, which was established on April 25, 2012, provides for the granting of incentive stock options, time-based or performance-based non-statutory stock options, share appreciation rights, restricted shares, time-based or performance-based RSUs, performance-based awards and other share-based grants or any combination thereof (collectively referred to as ‘Awards’) to employees, officers, non-employee directors and consultants (‘Eligible Individuals’) of the Company (‘2012 Plan’). The board of directors also adopted a sub-plan under the 2012 plan to provide an employee sharesave scheme in the U.K.

There were approximately 7 million shares remaining available for grant under this plan as of December 31, 2018. Options are exercisable on a variety of dates, including from the second, third, fourth or fifth anniversary of the grant date. Unless terminated sooner by the board of directors, the 2012 Plan will expire 10 years after the date of its adoption. That termination will not affect the validity of any grants outstanding at that date.

Towers Watson Share Plans

In January 2016, in connection with the Merger, we assumed the Towers Watson & Co. 2009 Long-Term Incentive Plan (‘LTIP’) and converted the outstanding unvested restricted stock units and options into Willis Towers Watson RSUs and options using a conversion ratio stated in the Merger Agreement. We determined the fair value of the portion of the outstanding RSUs and options related to pre-acquisition employee service using the straight-line methodology from the date of grant to the acquisition date to be $37 million, which was added to the transaction consideration. The fair value of the remaining portion of RSUs and options related to the post-acquisition employee services was $45 million, and was recorded over the subsequent vesting periods. For the years ended December 31, 2018, 2017 and 2016, we recorded $3 million, $11 million and $31 million of non-cash stock based compensation expense, respectively.

The acquired awards included performance-vested RSUs. Under the RSU agreement, participants became vested in a number of RSUs based on the achievement of specified levels of financial performance during the performance period set forth in the Merger Agreement, provided that the participant remained in continuous service with us through the end of the performance period. Dividend equivalents accrued on these RSUs and vested to the same extent as the underlying shares. The Compensation Committee of the board of directors did provide for the continuation of the vesting of RSUs upon an employee’s termination under certain circumstances such as qualified retirement. The definition of qualified retirement is age 55 with 15 years of service with the Company and a minimum of one year of service in the performance period. Based on the terms of the RSU agreement, the achievement of the level of financial performance was determined at the higher of 100% or the level attained at the time of the Merger.

The Company does not intend to grant future awards under the 2009 LTIP plan.

Employee Stock Purchase Plans

The Company adopted the Willis Group Holdings 2010 North America Employee Stock Purchase Plan, which expires on May 31, 2020. These plans provide certain eligible employees in the United States and Canada with the ability to contribute payroll deductions to the purchase of Willis Towers Watson ordinary shares at the end of each offering period.

Options

Valuation Assumptions

The fair value of each option is estimated on the date of grant using the Black-Scholes option pricing model that uses the assumptions noted in the following table. Expected volatility is based on historical volatility of the Company’s shares. The Company uses the simplified method set out in ASC 718 – Compensation – Stock Compensation to derive the expected term of options granted as it does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term. The risk-free interest rate for periods within the expected life of the option is based on the U.S. Treasury yield curve in effect at the time of grant. The assumptions noted in the table below represent the weighted-average of each assumption for each grant during the year.

	Years ended December 31,
	2017			2016
Expected volatility		19.8	%		21.0	%
Expected dividends		1.4	%		1.5	%
Expected life (years)		4.2			2.7
Risk-free interest rate		1.6	%		0.7	%

There were no options granted during the year ended December 31, 2018.

Award Activity

Classification of options as time-based or performance-based is dependent on the original terms of the award. Performance conditions on the majority of options have been met. A summary of option activity under the plans at December 31, 2018, and changes during the year then ended is presented below:

	Options (thousands)		Weighted- Average Exercise Price ⁽ⁱ⁾		Weighted- Average Remaining Contractual Term	Aggregate Intrinsic Value
Time-based stock options
Balance as of December 31, 2017		754	$	103.85
Granted		—	$	—
Exercised		294	$	107.96
Expired		11	$	102.19
Balance as of December 31, 2018		449	$	101.21	3 years	$	23
Options vested or expected to vest at December 31, 2018		445	$	100.97	3 years	$	23
Options exercisable at December 31, 2018		329	$	99.48	3 years	$	17
Performance-based stock options
Balance as of December 31, 2017		680	$	106.42
Granted		—	$	—
Exercised		138	$	96.02
Forfeited		—	$	—
Balance as of December 31, 2018		542	$	110.55	3 years	$	22
Options vested or expected to vest at December 31, 2018		542	$	110.55	3 years	$	22
Options exercisable at December 31, 2018		542	$	110.55	3 years	$	22

(i)	Certain options are exercisable in Pounds sterling and are converted to dollars using the exchange rate at December 31, 2018.

The weighted-average grant-date fair values of time-based options granted during the years ended December 31, 2017 and 2016 were $27.69 and $16.88, respectively. The total intrinsic values of time-based options exercised during the years ended December 31, 2018, 2017 and 2016 were $12 million, $19 million and $25 million, respectively. At December 31, 2018, there was $1 million of total unrecognized compensation cost under the time-based stock option plans; that cost is expected to be recognized over a weighted-average period of less than one year.

The total intrinsic values of performance-based options exercised during the years ended December 31, 2018, 2017 and 2016 were $8 million, $10 million and $9 million, respectively. At December 31, 2018, there is no unrecognized compensation cost related to the performance-based stock option plans.

Cash received from option exercises under all share-based payment arrangements for the years ended December 31, 2018, 2017 and 2016 was $45 million, $61 million and $63 million, respectively. The actual tax benefit recognized for the tax deductions from option exercises of the share-based payment arrangements totaled $4 million, $7 million and $6 million for the years ended December 31, 2018, 2017 and 2016, respectively.

Equity-settled RSUs

Valuation Assumptions

The fair value of each time-based RSU is based on the grant date fair value, or the fair value on the acquisition date in the case of acquired awards. The fair value of each performance-based RSU is estimated on the grant date using a Monte-Carlo simulation that uses the assumptions noted in the following table. The awards also contain a market-based performance target. For the awards granted in 2018, the performance measure is entirely based on this market target. Expected volatility is based on the historical volatility of the Company’s shares. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of the grant. The assumptions noted in the table below represent the weighted-average of each assumption for each grant during the year.

	Years ended December 31,
	2018			2017			2016
Expected volatility		17.9	%		20.2	%		20.3	%
Expected dividend yield		—	%		—	%		—	%
Expected life (years)		2.5			2.4			2.6
Risk-free interest rate		2.6	%		1.4	%		0.8	%

Award Activity

A summary of time-based and performance-based RSU activity under the plans at December 31, 2018, and changes during the year then ended, is presented below:

	Shares (thousands)		Weighted- Average Grant Date Fair Value
Nonvested shares (time-based RSUs)
Balance as of December 31, 2017		143	$	122.27
Granted		51	$	153.58
Vested		165	$	122.61
Forfeited		10	$	117.09
Balance as of December 31, 2018		19	$	141.19
Nonvested shares (performance-based RSUs)
Balance as of December 31, 2017		881	$	90.61
Granted		141	$	204.13
Vested		250	$	125.75
Forfeited		14	$	118.94
Balance as of December 31, 2018		758	$	91.02

The total number of time-based RSUs that vested during the year ended December 31, 2018 was 164,728 shares at an average share price of $156.14. The total number of time-based RSUs that vested during the year ended December 31, 2017 was 178,574 shares at an average share price of $150.81. The total number of time-based RSUs that vested during the year ended December 31, 2016 was 459,838 shares at an average share price of $120.42. At December 31, 2018 there was $2 million of total unrecognized compensation cost related to the time-based RSU plan; that cost is expected to be recognized over a weighted-average period of 1.4 years.

The total number of performance-based RSUs that vested during the year ended December 31, 2018 was 249,901 shares at an average share price of $154.99. The total number of performance-based RSUs that vested during the year ended December 31, 2017 was 318,714 shares at an average share price of $140.32. The total number of performance-based RSUs that vested during the year ended December 31, 2016 was 258,536 shares at an average share price of $119.75. At December 31, 2018 there was $12 million of total unrecognized compensation cost related to the performance-based RSU plan; that cost is expected to be recognized over a weighted-average period of 1.9 years.

The actual tax benefit recognized for the tax deductions from RSUs that vested totaled $12 million, $19 million and $25 million for the years ended December 31, 2018, 2017 and 2016, respectively.

Phantom RSUs

The Company granted 268,956 units of phantom stock with a market-performance feature in the year ended December 31, 2018. These are cash-settled awards with final payout based on the performance of Company stock. The grant date fair value of the awards was $83.57 per share. The fair value of each phantom RSU is estimated using a Monte Carlo simulation. The Company’s stock price as of the last day of the period is one of the inputs into the model. Expected volatility is based on the historical volatility of the Company’s shares. The expected term of the plan is three years, based on the vesting terms of the award. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant.

Since the awards are cash-settled, they are considered a liability. Expense is recognized over the service period. The liability is remeasured at the end of each reporting period and changes in fair value are recognized as compensation cost. As of December 31, 2018, the liability recognized is $5 million and the estimated unrecognized compensation cost is $18 million.

Earnings Per Share

12 Months Ended

Dec. 31, 2018

Earnings Per Share [Abstract]

Earnings Per Share

Note 19 — Earnings Per Share

Basic and diluted earnings per share are calculated by dividing net income attributable to Willis Towers Watson by the average number of ordinary shares outstanding during each period. The computation of diluted earnings per share reflects the potential dilution that could occur if dilutive securities and other contracts to issue shares were exercised or converted into shares or resulted in the issuance of shares that then shared in the net income of the Company.

At December 31, 2018, 2017 and 2016, there were 0.4 million, 0.8 million and 1.2 million time-based share options; 0.5 million, 0.7 million and 0.9 million performance-based options; and 0.8 million, 0.9 million and 1.2 million performance-based RSUs outstanding, respectively. The Company’s time-based RSUs were immaterial at December 31, 2018; there were 0.1 million and 0.4 million time-based RSUs outstanding at December 31, 2017 and 2016, respectively. In addition, the Company had 0.3 million performance-based phantom units outstanding at December 31, 2018; there were no phantom units outstanding at December 31, 2017 and 2016.

Basic and diluted earnings per share are as follows:

	Years ended December 31,
	2018			2017			2016
Net income attributable to Willis Towers Watson	$	695		$	568		$	420

Basic weighted-average number of shares outstanding		131			135			137
Dilutive effect of potentially issuable shares		1			1			1
Diluted weighted-average number of shares outstanding		132			136			138

Basic earnings per share	$	5.29		$	4.21		$	3.07
Dilutive effect of potentially issuable shares		(0.02	)		(0.03	)		(0.03	)
Diluted earnings per share	$	5.27		$	4.18		$	3.04

There were no anti-dilutive options for the years ended December 31, 2018 and 2017. Options to purchase 0.5 million shares for the year ended December 31, 2016 were not included in the computation of the dilutive effect of stock options because their effect was anti-dilutive. For the year ended December 31, 2018, 0.2 million RSUs were not included in the computation of the dilutive effect of potentially issuable shares because their effect was anti-dilutive. There were no anti-dilutive RSUs for the years ended December 31, 2017 and 2016.

Supplemental Disclosures of Cash Flow Information

12 Months Ended

Dec. 31, 2018

Supplemental Cash Flow Elements [Abstract]

Supplemental Disclosures of Cash Flow Information

Note 20 — Supplemental Disclosures of Cash Flow Information

Supplemental disclosures regarding cash flow information and non-cash investing and financing activities are as follows:

	Years Ended December 31,
	2018		2017		2016
Supplemental disclosures of cash flow information:
Cash payments for income taxes, net	$	178	$	203	$	158
Cash payments for interest	$	176	$	169	$	143
Cash acquired	$	13	$	—	$	476
Supplemental disclosures of non-cash investing and financing activities:
Issuance of shares and assumed awards in connection with the Merger	$	—	$	—	$	8,723
Fair value of deferred and contingent consideration related to acquisitions	$	36	$	—	$	—

Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Data (Unaudited)

Note 21 — Quarterly Financial Data (Unaudited)

Quarterly financial data for 2018 and 2017 were as follows:

	Three Months Ended
	March 31,		June 30,		September 30,			December 31,
2018
Revenue	$	2,292	$	1,990	$	1,859		$	2,372
Total costs of providing services	$	2,033	$	1,927	$	1,842		$	1,902
Income from operations	$	259	$	63	$	17		$	470
Net income	$	221	$	65	$	46		$	383
Net income attributable to Willis Towers Watson	$	215	$	58	$	44		$	378
Earnings per share
— Basic	$	1.62	$	0.44	$	0.34		$	2.91
— Diluted	$	1.61	$	0.44	$	0.33		$	2.89
2017
Revenue	$	2,319	$	1,953	$	1,852		$	2,078
Total costs of providing services	$	1,918	$	1,892	$	1,878		$	1,998
Income/(loss) from operations	$	401	$	61	$	(26	)	$	80
Net income/(loss)	$	352	$	41	$	(54	)	$	253
Net income/(loss) attributable to Willis Towers Watson	$	344	$	33	$	(54	)	$	245
Earnings/(loss) per share
— Basic	$	2.51	$	0.24	$	(0.40	)	$	1.85
— Diluted	$	2.50	$	0.24	$	(0.40	)	$	1.84

Financial Information for Issuers and Other Guarantor Subsidiaries

12 Months Ended

Dec. 31, 2018

Condensed Financial Information Of Parent Company Only Disclosure [Abstract]

Financial Information for Issuers and Other Guarantor Subsidiaries

Note 22 — Financial Information for Issuers and Other Guarantor Subsidiaries

As of December 31, 2018 Willis Towers Watson has issued the following debt securities (‘WTW Debt Securities’):

Willis Towers Watson plc (the parent company) has $500 million senior notes outstanding, which were issued on March 15, 2016;

Willis North America Inc. (‘Willis North America’) has $1.8 billion senior notes outstanding, of which $187 million were issued on September 29, 2009, $650 million were issued on May 16, 2017, and $1.0 billion were issued on September 10, 2018; and

Trinity Acquisition plc has $2.1 billion senior notes outstanding, of which $525 million were issued on August 15, 2013, $1.0 billion were issued on March 22, 2016 and €540 million ($609 million) were issued on May 26, 2016, and $130 million currently outstanding on a consolidated basis under the $1.25 billion revolving credit facility issued on March 7, 2017.

The notes issued by the Company are guaranteed by the following additional wholly owned subsidiaries on a joint and several basis: Willis Netherlands B.V., Willis Investment U.K. Holdings Limited, TA I Limited, Trinity Acquisition plc, Willis Group Limited, Willis North America, Willis Towers Watson Sub Holdings Unlimited Company and Willis Towers Watson U.K. Holdings Limited.

The notes issued by Willis North America are guaranteed on a joint and several basis by the Company and each of the subsidiaries that guarantees the Company notes, except for Willis North America itself.

The notes issued by Trinity Acquisition plc are guaranteed on a joint and several basis by the Company and each of the subsidiaries that guarantees the Company notes, except for Trinity Acquisition plc itself.

For the purposes of this footnote, the companies that guarantee the Company notes, the Willis North America notes and the Trinity Acquisition plc notes, other than Willis North America and Trinity Acquisition plc, are referred to as the ‘other guarantors.’

The presentation of the financial information for issuers and other guarantor subsidiaries has been changed from prior filings in that the three previously disclosed separate notes that presented the three different issuer and related guarantor scenarios have been combined into one note. This new presentation still includes all of the financial information of the appropriate issuing and guarantor entities, with some immaterial reclassifications from what had been previously disclosed for each entity. We believe that this presentation will help to reduce the complexity of the information and offer a more meaningful analysis for the reader.

All intercompany receivables/payables have been presented in the condensed consolidating financial statements as non-current on a net presentation basis, rather than a gross basis, as this better reflects the nature of the intercompany positions and presents the funding or funded position that is due or owed. The equity method has been used for investments in subsidiaries in the condensed consolidating balance sheets of Willis Towers Watson plc, Willis North America, Trinity Acquisition plc and the other guarantors.

Presented below is condensed financial information for:

(i)

Willis Towers Watson plc, which is both an issuer and guarantor, on a parent company only basis;

(ii)

Willis North America, which is both an issuer and guarantor, on a company only basis;

(iii)

Trinity Acquisition plc, which is both an issuer and guarantor, on a company only basis;

(iv)

Other guarantors, which are all wholly owned direct or indirect subsidiaries of the parent, on a combined basis;

(v)

Non-guarantors, which are all wholly owned direct or indirect subsidiaries of the parent, on a combined basis;

(vi)

Eliminations, which are consolidating adjustments on a combined basis; and

(vii)

The consolidated Company.

Condensed Consolidating Statement of Comprehensive Income

	Year ended December 31, 2018
	Willis Towers Watson plc			Willis North America			Trinity Acquisition plc			Other guarantors			Non- guarantors			Eliminations			Consolidated
Revenue	$	—		$	34		$	—		$	—		$	8,479		$	—		$	8,513
Costs of providing services
Salaries and benefits		2			68			—			—			5,053			—			5,123
Other operating expenses		3			38			1			165			1,430			—			1,637
Depreciation		—			—			—			4			204			—			208
Amortization		—			—			—			3			534			(3	)		534
Transaction and integration expenses		—			8			—			1			193			—			202
Total costs of providing services		5			114			1			173			7,414			(3	)		7,704
(Loss)/income from operations		(5	)		(80	)		(1	)		(173	)		1,065			3			809
Intercompany income/(expense)		—			56			124			356			(536	)		—			—
Interest expense		(30	)		(58	)		(104	)		—			(16	)		—			(208	)
Other income, net		—			—			—			2			1,540			(1,292	)		250
(LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES		(35	)		(82	)		19			185			2,053			(1,289	)		851
(Provision for)/benefit from income taxes		—			(1	)		(3	)		41			(173	)		—			(136	)
Equity account for subsidiaries		730			124			437			498			—			(1,789	)		—
NET INCOME		695			41			453			724			1,880			(3,078	)		715
Income attributable to non-controlling interests		—			—			—			—			(20	)		—			(20	)
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON	$	695		$	41		$	453		$	724		$	1,860		$	(3,078	)	$	695

Comprehensive income/(loss) before non- controlling interests	$	247		$	(88	)	$	14		$	286		$	1,470		$	(1,662	)	$	267
Comprehensive income attributable to non- controlling interests		—			—			—			—			(20	)		—			(20	)
Comprehensive income/(loss) attributable to Willis Towers Watson	$	247		$	(88	)	$	14		$	286		$	1,450		$	(1,662	)	$	247

Condensed Consolidating Statement of Comprehensive Income

	Year ended December 31, 2017
	Willis Towers Watson plc			Willis North America			Trinity Acquisition plc			Other guarantors			Non- guarantors			Eliminations			Consolidated
Revenue	$	—		$	19		$	—		$	—		$	8,183		$	—		$	8,202
Costs of providing services
Salaries and benefits		4			48			—			—			4,915			—			4,967
Other operating expenses		3			20			1			91			1,419			—			1,534
Depreciation		—			—			—			6			197			—			203
Amortization		—			—			—			3			581			(3	)		581
Restructuring costs		—			15			—			8			109			—			132
Transaction and integration expenses		—			19			—			73			177			—			269
Total costs of providing services		7			102			1			181			7,398			(3	)		7,686
(Loss)/income from operations		(7	)		(83	)		(1	)		(181	)		785			3			516
Intercompany income/(expense)		—			34			123			350			(507	)		—			—
Interest expense		(30	)		(35	)		(103	)		—			(20	)		—			(188	)
Other income, net		35			—			—			—			367			(238	)		164
(LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES		(2	)		(84	)		19			169			625			(235	)		492
(Provision for)/benefit from income taxes		—			(29	)		(2	)		53			78			—			100
Equity account for subsidiaries		570			171			290			370			—			(1,401	)		—
NET INCOME		568			58			307			592			703			(1,636	)		592
Income attributable to non-controlling interests		—			—			—			—			(24	)		—			(24	)
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON	$	568		$	58		$	307		$	592		$	679		$	(1,636	)	$	568

Comprehensive income before non- controlling interests	$	939		$	197		$	663		$	952		$	1,051		$	(2,826	)	$	976
Comprehensive income attributable to non- controlling interests		—			—			—			—			(37	)		—			(37	)
Comprehensive income attributable to Willis Towers Watson	$	939		$	197		$	663		$	952		$	1,014		$	(2,826	)	$	939

Condensed Consolidating Statement of Comprehensive Income

	Year ended December 31, 2016
	Willis Towers Watson plc			Willis North America			Trinity Acquisition plc			Other guarantors			Non- guarantors			Eliminations			Consolidated
Revenue	$	—		$	19		$	—		$	2		$	7,866		$	—			7,887
Costs of providing services
Salaries and benefits		2			15			—			1			4,831			—			4,849
Other operating expenses		3			88			—			112			1,348			—			1,551
Depreciation		—			14			—			5			159			—			178
Amortization		—			—			—			—			591			—			591
Restructuring costs		—			39			—			29			125			—			193
Transaction and integration expenses		1			26			—			16			134			—			177
Total costs of providing services		6			182			—			163			7,188			—			7,539
(Loss)/income from operations		(6	)		(163	)		-			(161	)		678			—			348
Intercompany income/(expense)		—			109			106			320			(535	)		—			—
Interest expense		(32	)		(39	)		(90	)		—			(23	)		—			(184	)
Other income, net		—			—			—			2			176			—			178
(LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES		(38	)		(93	)		16			161			296			—			342
Benefit from/(provision for) income taxes		—			86			(3	)		39			(26	)		—			96
Equity account for subsidiaries		458			157			151			247			—			(1,013	)		—
NET INCOME		420			150			164			447			270			(1,013	)		438
Income attributable to non-controlling interests		—			—			—			—			(18	)		—			(18	)
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON	$	420		$	150		$	164		$	447		$	252		$	(1,013	)	$	420

Comprehensive loss before non- controlling interests	$	(427	)	$	(266	)	$	(656	)	$	(381	)	$	(549	)	$	1,850		$	(429	)
Comprehensive loss attributable to non- controlling interests		—			—			—			—			2			—			2
Comprehensive loss attributable to Willis Towers Watson	$	(427	)	$	(266	)	$	(656	)	$	(381	)	$	(547	)	$	1,850		$	(427	)

Condensed Consolidating Balance Sheet

	As of December 31, 2018
	Willis Towers Watson plc		Willis North America		Trinity Acquisition plc		Other guarantors		Non- guarantors		Eliminations			Consolidated
ASSETS
Cash and cash equivalents	$	—	$	—	$	—	$	—	$	1,033	$	—		$	1,033
Fiduciary assets		—		—		—		—		12,604		—			12,604
Accounts receivable, net		—		24		—		—		2,355		—			2,379
Prepaid and other current assets		—		311		1		33		357		(298	)		404
Total current assets		—		335		1		33		16,349		(298	)		16,420
Intercompany receivables, net		4,755		—		1,355		—		—		(6,110	)		—
Fixed assets, net		—		—		—		16		926		—			942
Goodwill		—		—		—		—		10,465		—			10,465
Other intangible assets, net		—		—		—		58		3,318		(58	)		3,318
Pension benefits assets		—		—		—		—		773		—			773
Other non-current assets		—		92		2		49		452		(128	)		467
Total non-current assets		4,755		92		1,357		123		15,934		(6,296	)		15,965
Investments in subsidiaries		5,691		6,649		2,677		8,108		—		(23,125	)		—
TOTAL ASSETS	$	10,446	$	7,076	$	4,035	$	8,264	$	32,283	$	(29,719	)	$	32,385
LIABILITIES AND EQUITY
Fiduciary liabilities	$	—	$	—	$	—	$	—	$	12,604	$	—		$	12,604
Deferred revenue and accrued expenses		1		2		—		3		1,641		—			1,647
Short-term debt and current portion of long-term debt		—		186		—		—		—		—			186
Other current liabilities		95		38		33		13		935		(250	)		864
Total current liabilities		96		226		33		16		15,180		(250	)		15,301
Intercompany payables, net		—		902		—		4,691		517		(6,110	)		—
Long-term debt		498		1,635		2,256		—		—		—			4,389
Liability for pension benefits		—		—		—		—		1,170		—			1,170
Deferred tax liabilities		—		—		—		—		688		(129	)		559
Provision for liabilities		—		120		—		—		420		—			540
Other non-current liabilities		—		13		—		5		411		—			429
Total non-current liabilities		498		2,670		2,256		4,696		3,206		(6,239	)		7,087
TOTAL LIABILITIES		594		2,896		2,289		4,712		18,386		(6,489	)		22,388
REDEEMABLE NON-CONTROLLING INTEREST		—		—		—		—		26		—			26
EQUITY
Total Willis Towers Watson shareholders’ equity		9,852		4,180		1,746		3,552		13,752		(23,230	)		9,852
Non-controlling interests		—		—		—		—		119		—			119
Total equity		9,852		4,180		1,746		3,552		13,871		(23,230	)		9,971
TOTAL LIABILITIES AND EQUITY	$	10,446	$	7,076	$	4,035	$	8,264	$	32,283	$	(29,719	)	$	32,385

Condensed Consolidating Balance Sheet

	As of December 31, 2017
	Willis Towers Watson plc		Willis North America		Trinity Acquisition plc		Other guarantors		Non guarantors		Eliminations			Consolidated
ASSETS
Cash and cash equivalents	$	2	$	—	$	—	$	1	$	1,027	$	—		$	1,030
Fiduciary assets		—		—		—		—		12,155		—			12,155
Accounts receivable, net		—		4		—		—		2,242		—			2,246
Prepaid and other current assets		—		267		1		44		264		(146	)		430
Total current assets		2		271		1		45		15,688		(146	)		15,861
Intercompany receivables, net		6,202		—		2,501		—		—		(8,703	)		-
Fixed assets, net		—		—		—		25		960		—			985
Goodwill		—		—		—		—		10,519		—			10,519
Other intangible assets, net		—		—		—		60		3,882		(60	)		3,882
Pension benefits assets		—		—		—		—		764		—			764
Other non-current assets		—		115		3		31		388		(90	)		447
Total non-current assets		6,202		115		2,504		116		16,513		(8,853	)		16,597
Investments in subsidiaries		4,506		6,125		1,918		8,425		—		(20,974	)		—
TOTAL ASSETS	$	10,710	$	6,511	$	4,423	$	8,586	$	32,201	$	(29,973	)	$	32,458
LIABILITIES AND EQUITY
Fiduciary liabilities	$	—	$	—	$	—	$	—	$	12,155	$	—		$	12,155
Deferred revenue and accrued expenses		—		19		—		7		1,685		—			1,711
Short-term debt and current portion of long-term debt		—		—		—		—		85		—			85
Other current liabilities		87		83		33		27		724		(150	)		804
Total current liabilities		87		102		33		34		14,649		(150	)		14,755
Intercompany payables, net		—		787		—		3,895		4,021		(8,703	)		—
Long-term debt		497		986		2,883		—		84		—			4,450
Liability for pension benefits		—		—		—		—		1,259		—			1,259
Deferred tax liabilities		—		—		—		—		704		(89	)		615
Provision for liabilities		—		120		—		—		438		—			558
Other non-current liabilities		—		19		—		5		520		—			544
Total non-current liabilities		497		1,912		2,883		3,900		7,026		(8,792	)		7,426
TOTAL LIABILITIES		584		2,014		2,916		3,934		21,675		(8,942	)		22,181
REDEEMABLE NON-CONTROLLING INTEREST		—		—		—		—		28		—			28
EQUITY
Total Willis Towers Watson shareholders’ equity		10,126		4,497		1,507		4,652		10,375		(21,031	)		10,126
Non-controlling interests		—		—		—		—		123		—			123
Total equity		10,126		4,497		1,507		4,652		10,498		(21,031	)		10,249
TOTAL LIABILITIES AND EQUITY	$	10,710	$	6,511	$	4,423	$	8,586	$	32,201	$	(29,973	)	$	32,458

Condensed Consolidating Statement of Cash Flows

	Year ended December 31, 2018
	Willis Towers Watson plc			Willis North America			Trinity Acquisition plc			Other guarantors			Non- guarantors			Eliminations			Consolidated
NET CASH (USED IN)/FROM OPERATING ACTIVITIES	$	(537	)	$	153		$	355		$	(792	)	$	3,196		$	(1,087	)	$	1,288
CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES
Additions to fixed assets and software for internal use		—			—			—			(4	)		(264	)		—			(268	)
Capitalized software costs		—			—			—			—			(54	)		—			(54	)
Acquisitions of operations, net of cash acquired		—			—			—			—			(36	)		—			(36	)
Net proceeds from sale of operations		—			—			—			—			4			—			4
Other, net		—			—			—			—			13			—			13
Proceeds from/(repayments of) intercompany investing activities, net		1,398			369			92			356			(2,673	)		458			—
Net cash from/(used in) investing activities	$	1,398		$	369		$	92		$	352		$	(3,010	)	$	458		$	(341	)
CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES
Net payments on revolving credit facility		—			(155	)		(599	)		—			—			—			(754	)
Senior notes issued		—			998			—			—			—			—			998
Debt issuance costs		—			(8	)		—			—			—			—			(8	)
Repayments of debt		—			—			—			—			(170	)		—			(170	)
Repurchase of shares		(602	)		—			—			—			—			—			(602	)
Proceeds from issuance of shares		45			—			—			—			—			—			45
Payments of deferred and contingent consideration related to acquisitions		—			—			—			—			(50	)		—			(50	)
Cash paid for employee taxes on withholding shares		—			—			—			—			(30	)		—			(30	)
Dividends paid		(306	)		—			(686	)		(150	)		(251	)		1,087			(306	)
Acquisitions of and dividends paid to non- controlling interests		—			—			—			—			(26	)		—			(26	)
(Repayments of)/proceeds from intercompany financing activities, net		—			(1,357	)		838			589			388			(458	)		—
Net cash (used in)/from financing activities	$	(863	)	$	(522	)	$	(447	)	$	439		$	(139	)	$	629		$	(903	)
(DECREASE)/INCREASE IN CASH AND CASH EQUIVALENTS		(2	)		—			—			(1	)		47			—			44
Effect of exchange rate changes on cash and cash equivalents		—			—			—			—			(41	)		—			(41	)
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR		2			—			—			1			1,027			—			1,030
CASH AND CASH EQUIVALENTS, END OF YEAR	$	—		$	—		$	—		$	—		$	1,033		$	—		$	1,033

Condensed Consolidating Statement of Cash Flows

	Year ended December 31, 2017
	Willis Towers Watson plc			Willis North America			Trinity Acquisition plc			Other guarantors			Non- guarantors			Eliminations			Consolidated
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	$	743		$	114		$	29		$	(696	)	$	939		$	(267	)	$	862
CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES
Additions to fixed assets and software for internal use		—			—			—			(8	)		(292	)		—			(300	)
Capitalized software costs		—			—			—			—			(75	)		—			(75	)
Acquisitions of operations, net of cash acquired		—			—			—			—			(13	)		—			(13	)
Net proceeds from sale of operations		—			—			—			—			57			—			57
Other, net		—			—			—			—			(4	)		—			(4	)
Proceeds from/(repayments of) intercompany investing activities, net		1,042			(55	)		(1,600	)		277			(485	)		821			—
(Increase)/decrease in investment in subsidiaries		(1,035	)		(115	)		(148	)		833			465			—			—
Net cash from/(used in) investing activities	$	7		$	(170	)	$	(1,748	)	$	1,102		$	(347	)	$	821		$	(335	)
CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES
Net borrowings on revolving credit facility		—			155			487			—			—			—			642
Senior notes issued		—			649			—			—			—			—			649
Proceeds from issuance of other debt		—			—			—			—			32			—			32
Debt issuance costs		—			(5	)		(4	)		—			—			—			(9	)
Repayments of debt		—			(394	)		(220	)		—			(120	)		—			(734	)
Repurchase of shares		(532	)		—			—			—			—			—			(532	)
Proceeds from issuance of shares		61			—			—			—			—			—			61
Payments related to share cancellation		—			—			—			—			(177	)		—			(177	)
Payments of deferred and contingent consideration related to acquisitions		—			—			—			—			(65	)		—			(65	)
Cash paid for employee taxes on withholding shares		—			—			—			—			(18	)		—			(18	)
Dividends paid		(277	)		(58	)		—			(58	)		(151	)		267			(277	)
Acquisitions of and dividends paid to non- controlling interests		—			—			—			—			(51	)		—			(51	)
(Repayments of)/proceeds from intercompany financing activities, net		—			(291	)		1,456			(347	)		3			(821	)		—
Net cash (used in)/from financing activities	$	(748	)	$	56		$	1,719		$	(405	)	$	(547	)	$	(554	)	$	(479	)
INCREASE IN CASH AND CASH EQUIVALENTS		2			—			—			1			45			—			48
Effect of exchange rate changes on cash and cash equivalents		—			—			—			—			112			—			112
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR		—			—			—			—			870			—			870
CASH AND CASH EQUIVALENTS, END OF YEAR	$	2		$	—		$	—		$	1		$	1,027		$	—		$	1,030

Condensed Consolidating Statement of Cash Flows

	Year ended December 31, 2016
	Willis Towers Watson plc			Willis North America			Trinity Acquisition plc			Other guarantors			Non- guarantors			Eliminations			Consolidated
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	$	(20	)	$	(83	)	$	152		$	440		$	1,114		$	(670	)	$	933
CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES
Additions to fixed assets and software for internal use		—			(12	)		—			(79	)		(221	)		94			(218	)
Capitalized software costs		—			—			—			—			(85	)		—			(85	)
Acquisitions of operations, net of cash acquired		—			—			—			—			476			—			476
Net proceeds from sale of operations		—			—			—			—			(4	)		3			(1	)
Other, net		—			33			—			—			20			(30	)		23
Proceeds from/(repayments of) intercompany investing activities, net		(3,751	)		—			(547	)		(3,405	)		(739	)		8,442			—
Decrease/(increase) in investment in subsidiaries		4,600			—			—			(1,000	)		(3,600	)		—			—
Net cash from/(used in) investing activities	$	849		$	21		$	(547	)	$	(4,484	)	$	(4,153	)	$	8,509		$	195
CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES
Net payments on revolving credit facility		—			—			(237	)		—			—			—			(237	)
Senior notes issued		—			—			1,606			—			—			—			1,606
Proceeds from issuance of other debt		—			—			400			—			4			—			404
Debt issuance costs		—			—			(14	)		—			—			—			(14	)
Repayments of debt		(300	)		—			(1,037	)		—			(564	)		—			(1,901	)
Repurchase of shares		(396	)		—			—			—			—			—			(396	)
Proceeds from issuance of shares		63			—			—			—			—			—			63
Payments of deferred and contingent consideration related to acquisitions		—			—			—			—			(67	)		—			(67	)
Cash paid for employee taxes on withholding shares		—			—			—			—			(13	)		—			(13	)
Dividends paid		(199	)		(49	)		(302	)		(162	)		(90	)		603			(199	)
Acquisitions of and dividends paid to non- controlling interests		—			—			—			—			(21	)		—			(21	)
Proceeds from/(repayments of) intercompany financing activities, net		—			111			(21	)		4,204			4,148			(8,442	)		—
Net cash (used in)/from financing activities	$	(832	)	$	62		$	395		$	4,042		$	3,397		$	(7,839	)	$	(775	)
(DECREASE)/INCREASE IN CASH AND CASH EQUIVALENTS		(3	)		—			—			(2	)		358			—			353
Effect of exchange rate changes on cash and cash equivalents		—			—			—			—			(15	)		—			(15	)
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR		3			—			—			2			527			—			532
CASH AND CASH EQUIVALENTS, END OF YEAR	$	—		$	—		$	—		$	—		$	870		$	—		$	870

Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements (Policies)

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Basis of Presentation

Principles of Consolidation

Use of Estimates

Going Concern

Fair Value of Financial Instruments

•

Level 1: refers to fair values determined based on quoted market prices in active markets for identical assets;

•

Level 2: refers to fair values estimated using observable market-based inputs or unobservable inputs that are corroborated by market data; and

•

Level 3: includes fair values estimated using unobservable inputs that are not corroborated by market data.

The following methods and assumptions were used by the Company in estimating its fair value disclosure for financial instruments:

•

Available-for-sale securities are classified as Level 1 because we use quoted market prices in determining the fair value of these securities.

•

Investments in Associates

Cash and Cash Equivalents

Fiduciary Assets and Liabilities

Fiduciary assets on the consolidated balance sheets are comprised of both fiduciary funds and fiduciary receivables:

Fiduciary liabilities on the consolidated balance sheets represent the obligations to remit all fiduciary funds and fiduciary receivables to insurers or insureds.

Accounts Receivable

Income Taxes

The Company recognizes interest and penalties relating to unrecognized tax benefits within income taxes. See Note 7 — Income Taxes for additional information regarding the Company’s income taxes.

Foreign Currency

Derivatives

Commitments, Contingencies and Accrued Liabilities

Share-Based Compensation

See Note 18 — Share-based Compensation for additional information about the Company’s share-based compensation.

Fixed Assets

Operating Leases

Operating Leases — Rentals payable on operating leases are charged on a straight-line basis to Other operating expenses in the consolidated statements of comprehensive income over the lease terms.

Goodwill and Other Intangible Assets

Acquired intangible assets are amortized over the following periods:



	Amortization basis	Expected life (years)
Client relationships	In line with underlying cash flows	5 to 20
Software	In line with underlying cash flows or straight-line basis	4 to 7
Product	In line with underlying cash flows	17.5
Trademark and trade name	Straight-line basis	14 to 25
Favorable agreements	Straight-line basis	7
Management contracts	Straight-line basis	18

Pensions

Revenue Recognition

We have engagement letters with our clients that specify the terms and conditions upon which the engagements are based. These terms and conditions can only be changed upon agreement by both parties.

We use different progress measures to determine our revenue depending on the nature of the engagement:

•

These contracts typically consist of an implementation phase and an ongoing administration phase:

•

Interest income — Interest income is recognized as earned.

For our broking business, the Company must estimate the fulfillment costs incurred during the pre-placement of the broking contracts. These judgments include:

•

which activities in the pre-placement process should be eligible for capitalization;

•

the amount of time and effort expended on those pre-placement activities;

•

the amount of payroll and related costs eligible for capitalization; and,

•

the monthly timing of underlying insurance and reinsurance policy inception dates.

Recent Accounting Pronouncements

Not yet adopted

•

Hindsight practical expedient – We have elected this practical expedient, and therefore will not revisit our estimate of lease terms upon transition to ASC 842.

•

Adopted

Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements (Tables)

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination

Acquired intangible assets are amortized over the following periods:



	Amortization basis	Expected life (years)
Client relationships	In line with underlying cash flows	5 to 20
Software	In line with underlying cash flows or straight-line basis	4 to 7
Product	In line with underlying cash flows	17.5
Trademark and trade name	Straight-line basis	14 to 25
Favorable agreements	Straight-line basis	7
Management contracts	Straight-line basis	18

Merger Acquisitions and Divestitures (Tables)

12 Months Ended

Dec. 31, 2018

Business Combinations [Abstract]

Calculation of Aggregate Merger Consideration

The table below presents the final calculation of aggregate Merger consideration.

	January 4, 2016
Number of shares of Towers Watson common stock outstanding as of January 4, 2016	69 million
Exchange ratio		2.6490
Number of Willis Group Holdings shares issued (prior to reverse stock split)	184 million
Willis Group Holdings price per share on January 4, 2016	$	47.18
Fair value of 184 million Willis ordinary shares	$	8,686
Value of equity awards assumed		37
Aggregate Merger consideration	$	8,723

Revenue (Tables)

12 Months Ended

Dec. 31, 2018

Revenue From Contract With Customer [Abstract]

Schedule Of Effect Of ASC 606 On Financial Statements

The cumulative effect of the changes made to our consolidated January 1, 2018 balance sheet for the adoption of ASC 606 were as follows:

Balance Sheet	Balance at December 31, 2017		Adjustments due to ASC 606				Balance at January 1, 2018
ASSETS
Accounts receivable, net	$	2,246	$	309		a	$	2,555
Prepaid and other current assets		430		89		b		519
Fixed assets, net		985		(83	)	c		902
Other non-current assets		447		39		c		486
LIABILITIES
Deferred revenue and accrued expenses		1,711		(74	)	d		1,637
Deferred tax liabilities		615		99		e		714
Provision for liabilities		558		12		f		570
EQUITY
Retained earnings		1,104		317		g		1,421

	Year Ended December 31, 2018
Statement of Comprehensive Income	As Reported			Balances Without Adoption of ASC 606			Effect of Change
Revenue	$	8,513		$	8,613		$	(100	)	h
Costs of providing services
Salaries and benefits		5,123			5,098			25		i
Depreciation		208			235			(27	)	i
Income from operations		809			907			(98	)
INCOME FROM OPERATIONS BEFORE INCOME TAXES		851			949			(98	)
Provision for income taxes		(136	)		(154	)		18		j
NET INCOME		715			795			(80	)
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON		695			775			(80	)

EARNINGS PER SHARE
Basic earnings per share	$	5.29		$	5.90		$	(0.61	)
Diluted earnings per share	$	5.27		$	5.87		$	(0.60	)

	As of December 31, 2018
Balance Sheet	As Reported		Balances Without Adoption of ASC 606		Effect of Change
ASSETS
Accounts receivable, net	$	2,379	$	2,198	$	181		a
Prepaid and other current assets		404		302		102		b
Fixed assets, net		942		1,051		(109	)	c
Other non-current assets		467		419		48		c
LIABILITIES
Deferred revenue and accrued expenses		1,647		1,754		(107	)	d
Other current liabilities		864		863		1		e
Deferred tax liabilities		559		479		80		e
Provision for liabilities		540		529		11		f
EQUITY
Retained earnings		1,201		964		237		g

	Year Ended December 31, 2018
Statement of Cash Flows	As Reported			Balances Without Adoption of ASC 606			Effect of Change
Net cash from operating activities	$	1,288		$	1,338		$	(50	)	k
Capitalized software costs		(54	)		(104	)		50		k

Explanation of Changes

The adoption of ASC 606 had the following impacts to our balance sheets at January 1, 2018 and December 31, 2018:

Provision for liabilities has been adjusted for additional reserves for long-term post-placement obligations in our broking business.

Retained earnings has been adjusted for the net impact of the adoption of ASC 606. See the discussion of the significant pre-tax changes by revenue in the following section.

	Retained Earnings Increase/(Decrease) at January 1, 2018			Increase/(Decrease) for the Year Ended December 31, 2018
Revenue adjustments
Medicare broking	$	311		$	(38	)
Proportional treaty reinsurance broking		50			2
Health and benefits broking		—			(57	)
Other adjustments		28			(7	)
Total adjustments related to revenue		389			(100	)

Cost adjustments
System implementation activities		(46	)		6
Other cost adjustments		75			(8	)
Total adjustments related to costs		29			(2	)

Tax effect		(101	)		(18	)
Total net adjustments	$	317		$	(80	)

Revenue was adjusted for the following significant changes:

•

The following changes are now reflected in our consolidated statement of cash flows for the year ended December 31, 2018.

Disaggregation of Revenue

The following table presents revenue by service offering and segment, as well as a reconciliation to total revenue for the year ended December 31, 2018. Along with reimbursable expenses and other, total revenue by service offering represents our revenue from customer contracts. See Note 5 — Segment Information for further information.

	Year ended December 31, 2018
	HCB		CRB		IRR		BDA		Corporate ⁽ⁱ⁾		Total
Broking	$	266	$	2,578	$	905	$	272	$	—	$	4,021
Consulting		2,224		163		430		—		13		2,830
Outsourced administration		484		65		—		486		—		1,035
Other		235		9		185		—		4		433
Total revenue by service offering		3,209		2,815		1,520		758		17		8,319
Reimbursable expenses and other ⁽ⁱ⁾		62		—		8		7		17		94
Total revenue from customer contracts	$	3,271	$	2,815	$	1,528	$	765	$	34	$	8,413
Interest and other income ⁽ⁱⁱ⁾		24		37		36		—		3		100
Total revenue	$	3,295	$	2,852	$	1,564	$	765	$	37	$	8,513

_________

(i)	Reimbursable expenses and other, as well as Corporate revenue, are excluded from segment revenue, but included in total revenue on the consolidated statements of comprehensive income.

(ii)	Interest and other income is included in segment revenue and total revenue, however it has been presented separately in the above tables because it does not arise directly from contracts with customers.

Individual revenue streams aggregating to 5% of total revenue for the year ended December 31, 2018 have been included within the Other line in the table above.

	Year ended December 31, 2018
	HCB		CRB		IRR		BDA		Corporate		Total
North America	$	1,849	$	1,044	$	416	$	758	$	16	$	4,083
Great Britain		481		648		732		—		—		1,861
Western Europe		562		631		218		—		1		1,412
International		317		492		154		—		—		963
Total revenue by geography	$	3,209	$	2,815	$	1,520	$	758	$	17	$	8,319

Contract with Customer, Asset and Liability

	December 31, 2018		January 1, 2018
Billed receivables, net of allowance for doubtful accounts of $40 million and $45 million	$	1,702	$	1,933
Unbilled receivables		356		276
Current contract assets		321		346
Accounts receivable, net	$	2,379	$	2,555
Non-current accounts receivable, net	$	20	$	33
Non-current contract assets	$	3	$	5
Deferred revenue	$	448	$	463

Schedule of Changes in Allowance for Doubtful Accounts

	December 31, 2018			December 31, 2017			December 31, 2016
Balance at beginning of year	$	45		$	40		$	22
Additions charged to costs and expenses		9			17			36
Charges to other accounts - acquisitions		—			—			8
Deductions/other movements		(15	)		(9	)		(27	)
Foreign exchange		1			(3	)		1
Balance at end of year	$	40		$	45		$	40

Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction

In addition, the Company has elected not to disclose the remaining performance obligations when one or both of the following circumstances apply:

•

Performance obligations which are part of a contract that has an original expected duration of less than one year, and

•

Performance obligations satisfied in accordance with ASC 606-10-55-18 (‘right to invoice’).

		2019				2020				2021 onward				Total
Revenue expected to be recognized on contracts as of December 31, 2018		$	441			$	357			$	466			$	1,264

Capitalized Contract Cost

The following table shows the categories of costs that are capitalized and deferred over the expected life of a contract.

	Costs to fulfill
Balance at January 1, 2018	$	126
New capitalized costs		465
Amortization		(442	)
Impairments		—
Foreign currency translation		(1	)
Balance at December 31, 2018	$	148

Segment Information (Tables)

12 Months Ended

Dec. 31, 2018

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment

The following table presents segment revenue and segment operating income for our reportable segments for the years ended December 31, 2018, 2017 and 2016.

	Segment revenue						Segment operating income
	Years ended December 31						Years ended December 31
	2018		2017		2016		2018		2017		2016
HCB	$	3,233	$	3,176	$	3,100	$	789	$	774	$	722
CRB		2,852		2,709		2,608		528		483		458
IRR		1,556		1,474		1,473		384		329		346
BDA		758		734		660		144		153		120
Total	$	8,399	$	8,093	$	7,841	$	1,845	$	1,739	$	1,646

Net Operating Income of the Reported Segments

The following table presents reconciliations of the information reported by segment to the Company’s consolidated amounts reported for the years ended December 31, 2018, 2017 and 2016.

	Years ended December 31,
	2018			2017			2016
Revenue:
Total segment revenue	$	8,399		$	8,093		$	7,841
Fair value adjustment to deferred revenue		—			—			(58	)
Reimbursable expenses and other		114			109			104
Revenue	$	8,513		$	8,202		$	7,887

Total segment operating income	$	1,845		$	1,739		$	1,646
Fair value adjustment for deferred revenue		—			—			(58	)
Amortization		(534	)		(581	)		(591	)
Restructuring costs		—			(132	)		(193	)
Transaction and integration expenses ⁽ⁱ⁾		(202	)		(269	)		(177	)
Provisions for significant litigation		—			(11	)		(50	)
Unallocated, net ⁽ⁱⁱ⁾		(300	)		(230	)		(229	)
Income from operations		809			516			348
Interest expense		(208	)		(188	)		(184	)
Other income, net		250			164			178
Income from operations before income taxes	$	851		$	492		$	342

(i)	Includes transaction and integration expenses related to the Merger and the acquisition of Gras Savoye.

(ii)	Includes certain costs, primarily related to corporate functions which are not directly related to the segments, and certain differences between budgeted expenses determined at the beginning of the year and actual expenses that we report for U.S. GAAP purposes.

Revenue and Long-lived Assets by Geographical Areas

	Revenue						Long-Lived Assets ⁽ⁱ⁾
	2018		2017		2016		2018		2017		2016
Ireland	$	138	$	107	$	92	$	78	$	127	$	114

United States		3,970		3,821		3,395		11,068		9,988		11,400
United Kingdom		1,926		1,815		2,236		2,349		3,173		2,431
Rest of World		2,479		2,459		2,164		2,411		3,263		2,466
Total Foreign Countries		8,375		8,095		7,795		15,828		16,424		16,297
	$	8,513	$	8,202	$	7,887	$	15,906	$	16,551	$	16,411

(i)	Long-lived assets do not include deferred tax assets.

Restructuring Costs (Tables)

12 Months Ended

Dec. 31, 2018

Restructuring And Related Activities [Abstract]

Analysis of the Cost for Restructuring

	HCB		CRB		IRR		BDA		Corporate		Total
Year ended December 31, 2017
Termination benefits	$	—	$	25	$	4	$	—	$	17	$	46
Professional services and other ⁽ⁱ⁾		3		63		6		—		14		86
Total	$	3	$	88	$	10	$	—	$	31	$	132

Year ended December 31, 2016
Termination benefits	$	33	$	26	$	6	$	1	$	2	$	68
Professional services and other ⁽ⁱ⁾		4		81		4		—		36		125
Total	$	37	$	107	$	10	$	1	$	38	$	193

(i)	Other includes salary and benefits, premises, and other expenses incurred to support the ongoing management and facilitation of the programs.

An analysis of the total cumulative restructuring costs recognized for the Operational Improvement Program from its commencement to December 31, 2017 by segment is as follows:

	HCB		CRB		IRR		BDA		Corporate		Total
2014
Termination benefits	$	—	$	15	$	1	$	—	$	—	$	16
Professional services and other ⁽ⁱ⁾		—		3		—		—		17		20
2015
Termination benefits	$	2	$	24	$	7	$	—	$	3	$	36
Professional services and other ⁽ⁱ⁾		1		57		2		—		30		90
2016
Termination benefits	$	1	$	18	$	3	$	—	$	1	$	23
Professional services and other ⁽ⁱ⁾		1		81		4		—		36		122
2017
Termination benefits	$	—	$	25	$	4	$	—	$	19	$	48
Professional services and other ⁽ⁱ⁾		3		63		6		—		14		86
Total
Termination benefits	$	3	$	82	$	15	$	—	$	23	$	123
Professional services and other ⁽ⁱ⁾		5		204		12		—		97		318
Total	$	8	$	286	$	27	$	—	$	120	$	441

(i)	Other includes salary and benefits, premises, and other expenses incurred to support the ongoing management and facilitation of the program.

Restructuring costs related to the Business Restructuring Program for the year ended December 31, 2016 by segment are as follows:

	HCB		CRB		IRR		BDA		Corporate		Total
	(in millions)
2016
Termination benefits	$	32	$	8	$	3	$	1	$	1	$	45
Professional services and other ⁽ⁱ⁾		3		—		—		—		—		3
Total	$	35	$	8	$	3	$	1	$	1	$	48

(i)	Other includes salary and benefits, premises, and other expenses incurred to support the ongoing management and facilitation of the program.

Schedule of Restructuring Liability

The changes in the Company’s liability under the Operational Improvement Program from its commencement to December 31, 2018, are as follows:

	Termination Benefits			Professional Services and Other			Total
Balance at January 1, 2014	$	—		$	—		$	—
Charges incurred		16			20			36
Cash payments		(11	)		(14	)		(25	)
Balance at December 31, 2014		5			6			11
Charges incurred		36			90			126
Cash payments		(26	)		(85	)		(111	)
Balance at December 31, 2015		15			11			26
Charges incurred		23			122			145
Cash payments		(31	)		(115	)		(146	)
Balance at December 31, 2016		7			18			25
Charges incurred		48			86			134
Cash payments		(41	)		(97	)		(138	)
Balance at December 31, 2017		14			7			21
Cash payments		(12	)		(6	)		(18	)
Balance at December 31, 2018	$	2		$	1		$	3

The changes in the Company’s liability under the Business Restructure Program from its commencement to December 31, 2018, are as follows:

	Termination Benefits			Professional Services and Other			Total
Balance at January 1, 2016	$	—		$	—		$	—
Charges incurred		45			3			48
Cash payments		(19	)		(3	)		(22	)
Balance at December 31, 2016		26			—			26
Adjustment to prior charges incurred		(2	)		—			(2	)
Cash payments		(23	)		—			(23	)
Balance at December 31, 2017		1			—			1
Cash payments		(1	)		—			(1	)
Balance at December 31, 2018	$	—		$	—		$	—

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Income from continuing operations before income taxes and interest in earnings of associates by location of taxing jurisdiction

An analysis of income from operations before income taxes by taxing jurisdiction is shown below:

	Years ended December 31,
	2018			2017			2016
Ireland	$	(16	)	$	(23	)	$	(27	)
U.S.		(101	)		(198	)		(311	)
U.K.		182			31			123
Other jurisdictions		786			682			557
Total	$	851		$	492		$	342

Provision for benefit from income taxes

The components of the (provision for)/benefit from income taxes include:

	Years ended December 31,
	2018			2017			2016
Current tax expense:
U.S. federal taxes	$	(98	)	$	(65	)	$	(35	)
U.S. state and local taxes		(25	)		(7	)		(14	)
U.K. corporation tax		(16	)		(14	)		(28	)
Other jurisdictions		(112	)		(99	)		(71	)
Total current tax expense		(251	)		(185	)		(148	)
Deferred tax benefit:
U.S. federal taxes		79			268			214
U.S. state and local taxes		12			(6	)		5
U.K. corporation tax		(6	)		9			(10	)
Other jurisdictions		30			14			35
Total deferred tax benefit		115			285			244
Total (provision for)/benefit from income taxes	$	(136	)	$	100		$	96

Reconciliation between US federal income taxes at the statutory rate and the Company's provision for income taxes on continuing operations

	Years ended December 31,
	2018			2017			2016
INCOME FROM OPERATIONS BEFORE INCOME TAXES	$	851		$	492		$	342
U.S. federal statutory income tax rate		21	%		35	%		35	%
Income tax expense at U.S. federal tax rate		(179	)		(172	)		(120	)
Adjustments to derive effective tax rate:
Non-deductible expenses and dividends		(44	)		(68	)		(15	)
Non-deductible acquisition costs		(2	)		(11	)		(1	)
Disposal of non-deductible goodwill		1			(11	)		(2	)
Impact of change in rate on deferred tax balances		7			—			15
Effect of foreign exchange and other differences		1			(3	)		(6	)
Non-deductible Venezuelan foreign exchange loss		—			(2	)		(4	)
Changes in valuation allowances		80			(13	)		74
Net tax effect of intra-group items		99			97			98
Tax differentials of non-U.S. jurisdictions		(2	)		69			80
Tax differentials of U.S. state taxes and local taxes		(77	)		6			(14	)
Global Intangible Low-Taxed Income (GILTI)		(15	)		—			—
Impact of U.S. Tax Reform		—			204			—
Other items, net		(5	)		4			(9	)
(Provision for)/benefit from income taxes	$	(136	)	$	100		$	96

Significant components of deferred income tax assets and liabilities and their balance sheet classifications

Deferred income tax assets and liabilities included in the consolidated balance sheets at December 31, 2018 and 2017 are comprised of the following:

	December 31,
	2018			2017
Deferred tax assets:
Accrued expenses not currently deductible	$	177		$	131
Net operating losses		91			145
Capital loss carryforwards		30			28
Accrued retirement benefits		285			339
Deferred compensation		82			69
Stock options		22			24
Financial derivative transactions		1			18
Gross deferred tax assets		688			754
Less: valuation allowance		(81	)		(162	)
Net deferred tax assets	$	607		$	592
Deferred tax liabilities:
Cost of intangible assets, net of related amortization	$	825		$	929
Cost of tangible assets, net of related depreciation		37			56
Prepaid retirement benefits		101			114
Accrued revenue not currently taxable		144			62
Deferred tax liabilities	$	1,107		$	1,161
Net deferred tax liabilities	$	500		$	569

	December 31,
	2018		2017
Balance sheet classifications:
Other non-current assets	$	59	$	46
Deferred tax liabilities		559		615
Net deferred tax liability	$	500	$	569

Summary of Valuation Allowance

An analysis of our valuation allowance is shown below.

	Years ended December 31,
	2018			2017			2016
Balance at beginning of year	$	162		$	134		$	187
Additions charged to costs and expenses		18			35			—
Additions charged against other accounts		—			—			21
Deductions		(99	)		(7	)		(74	)
Balance at end of year	$	81		$	162		$	134

Reconciliation of the beginning and ending amounts of unrecognized tax benefits

A reconciliation of the beginning and ending balances of the liability for unrecognized tax benefits is as follows:

	2018			2017			2016
Balance at beginning of year	$	59		$	56		$	22
Increases related to acquisitions		—			—			33
Increases related to tax positions in prior years		2			2			1
Decreases related to tax positions in prior years		(4	)		(5	)		(9	)
Decreases related to settlements		(4	)		—			(1	)
Decreases related to lapse in statute of limitations		(5	)		(2	)		(1	)
Increases related to current year tax positions		3			9			11
Cumulative translation adjustment and other adjustments		(2	)		(1	)		—
Balance at end of year	$	49		$	59		$	56

Summary of Income Tax Examinations



	Open Tax Years (fiscal year ending in)
U.S. — federal	2015 and forward
U.S. — various states	2013 and forward
U.K.	2010 and forward
Ireland	2014 and forward
France	2010 and forward
Germany	2010 and forward
Canada - federal	2011 and forward

Fixed Assets (Tables)

12 Months Ended

Dec. 31, 2018

Property Plant And Equipment [Abstract]

Property, Plant and Equipment

The following table reflects changes in the net carrying amount of the components of fixed assets for the year ended December 31, 2018 and 2017:

	Furniture, equipment and software			Leasehold improvements			Land and buildings			Total
Cost: at January 1, 2017	$	1,009		$	382		$	90		$	1,481
Additions		303			91			—			394
Disposals		(61	)		(21	)		—			(82	)
Foreign exchange		49			16			4			69
Cost: at December 31, 2017		1,300			468			94			1,862
Additions		249			70			—			319
Disposals		(278	)		(35	)		—			(313	)
Reclassification due to ASC 606 ⁽ⁱ⁾		(102	)		—			—			(102	)
Foreign exchange		(39	)		(15	)		(2	)		(56	)
Cost: at December 31, 2018	$	1,130		$	488		$	92		$	1,710

Depreciation: at January 1, 2017	$	(464	)	$	(137	)	$	(41	)	$	(642	)
Depreciation expense ⁽ⁱⁱ⁾		(199	)		(47	)		(6	)		(252	)
Disposals		37			14			—			51
Foreign exchange		(26	)		(6	)		(2	)		(34	)
Depreciation: at December 31, 2017		(652	)		(176	)		(49	)		(877	)
Depreciation expense ⁽ⁱⁱ⁾		(155	)		(54	)		(4	)		(213	)
Disposals		250			27			—			277
Reclassification due to ASC 606 ⁽ⁱ⁾		19			—			—			19
Foreign exchange		19			6			1			26
Depreciation: at December 31, 2018	$	(519	)	$	(197	)	$	(52	)	$	(768	)

Net book value:
At December 31, 2017	$	648		$	292		$	45		$	985

At December 31, 2018	$	611		$	291		$	40		$	942

Capital Leases

Included within land and buildings are the following assets held under capital leases:

	December 31,
	2018			2017
Capital leases	$	31		$	31
Accumulated depreciation		(16	)		(14	)
	$	15		$	17

Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2018

Goodwill And Intangible Assets Disclosure [Abstract]

Components of Goodwill

The components of goodwill are outlined below for the years ended December 31, 2018 and 2017:

	HCB			CRB			IRR			BDA		Total
Balance at December 31, 2016
Goodwill, gross	$	4,412		$	2,178		$	1,758		$	2,557	$	10,905
Accumulated impairment losses		(130	)		(362	)		—			—		(492	)
Goodwill, net - December 31, 2016		4,282			1,816			1,758			2,557		10,413
Goodwill reassigned in segment realignment		(113	)		13			100			—		—
Goodwill acquired during the period		—			8			—			—		8
Goodwill disposed of during the period		(31	)		(5	)		(27	)		—		(63	)
Foreign exchange		74			67			20			—		161
Balance at December 31, 2017
Goodwill, gross		4,342			2,261			1,851			2,557		11,011
Accumulated impairment losses		(130	)		(362	)		—			—		(492	)
Goodwill, net - December 31, 2017		4,212			1,899			1,851			2,557		10,519
Goodwill reassigned in segment realignment ⁽ⁱ⁾		—			72			(72	)		—		—
Goodwill acquired during the period		—			9			29			—		38
Goodwill disposed of during the period		—			—			(5	)		—		(5	)
Foreign exchange		(42	)		(34	)		(11	)		—		(87	)
Balance at December 31, 2018
Goodwill, gross		4,300			2,308			1,792			2,557		10,957
Accumulated impairment losses		(130	)		(362	)		—			—		(492	)
Goodwill, net - December 31, 2018	$	4,170		$	1,946		$	1,792		$	2,557	$	10,465

(i)	Represents the reallocation of goodwill related to certain businesses which were realigned among the segments as of January 1, 2018. See Note 5 — Segment Information for further information.

Changes in the Net Carrying Amount of the Components of Finite-Lived Intangible Assets

The following table reflects changes in the net carrying amounts of the components of finite-lived intangible assets for the year ended December 31, 2018:

	Balance at December 31, 2017		Intangible assets acquired		Intangible assets disposed			Amortization ⁽ⁱ⁾			Foreign exchange			Balance at December 31, 2018
Client relationships	$	2,342	$	39	$	(7	)	$	(341	)	$	(47	)	$	1,986
Management contracts		56		—		—			(4	)		(4	)		48
Software		473		—		—			(140	)		(5	)		328
Trademark and trade name		966		—		—			(44	)		(2	)		920
Product		33		—		—			(4	)		(2	)		27
Favorable agreements		10		—		—			(2	)		1			9
Other		2		—		—			(1	)		(1	)		—
Total amortizable intangible assets	$	3,882	$	39	$	(7	)	$	(536	)	$	(60	)	$	3,318

(i)	Amortization associated with favorable lease agreements is recorded in Other operating expenses in the consolidated statements of comprehensive income.

The following table reflects changes in the net carrying amounts of the components of finite-lived intangible assets for the year ended December 31, 2017:

	Balance at December 31, 2016		Intangible assets acquired		Intangible assets disposed			Amortization ⁽ⁱⁱ⁾			Foreign exchange		Balance at December 31, 2017
Client relationships	$	2,655	$	13	$	(44	)	$	(379	)	$	97	$	2,342
Management contracts		54		—		—			(4	)		6		56
Software ⁽ⁱ⁾		570		36		—			(150	)		17		473
Trademark and trade name		1,006		—		(1	)		(44	)		5		966
Product		33		—		—			(3	)		3		33
Favorable agreements		11		1		—			(2	)		—		10
Other		3		—		—			(1	)		—		2
Total amortizable intangible assets	$	4,332	$	50	$	(45	)	$	(583	)	$	128	$	3,882

(i)

(ii)	Amortization associated with favorable lease agreements is recorded in Other operating expenses in the consolidated statements of comprehensive income.

Schedule of Carrying Values of Finite-Lived Intangible Assets and Liabilities

The following table reflects the carrying values of finite-lived intangible assets and liabilities at December 31, 2018 and December 31, 2017:

	December 31, 2018					December 31, 2017
	Gross Carrying Amount		Accumulated Amortization			Gross Carrying Amount		Accumulated Amortization
Client relationships	$	3,401	$	(1,415	)	$	3,462	$	(1,120	)
Management contracts		63		(15	)		68		(12	)
Software		749		(421	)		764		(291	)
Trademark and trade name		1,052		(132	)		1,055		(89	)
Product		36		(9	)		39		(6	)
Favorable agreements		14		(5	)		14		(4	)
Other		3		(3	)		6		(4	)
Total finite-lived assets	$	5,318	$	(2,000	)	$	5,408	$	(1,526	)

Unfavorable agreements	$	34	$	(13	)	$	34	$	(8	)
Total finite-lived intangible liabilities	$	34	$	(13	)	$	34	$	(8	)

Schedule of Future Amortization Expense and Rent Offset

Years ended December 31,	Amortization		Rent offset
2019	$	472	$	(2	)
2020		420		(2	)
2021		344		(2	)
2022		287		(3	)
2023		239		(2	)
Thereafter		1,547		(1	)
Total	$	3,309	$	(12	)

Derivative Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2018

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Schedule of Derivative Instruments Designated As Hedging Instrument Effect on Other Comprehensive Income (Loss)

(Loss)/gain

recognized in OCI

(effective element)

Location of loss reclassified from Accumulated OCL into income (effective element)

Loss

reclassified from Accumulated

OCL into income

(effective element)

Location of

loss recognized in

income (ineffective

portion and amount

excluded from

effectiveness testing)

Loss

recognized in income

(ineffective portion and

amount excluded from

effectiveness testing)

2018

2017

2016

2018

2017

2016

2018

2017

2016

Foreign exchange

contracts

(22

)

(127

)

Other income, net

(28

)

(53

)

(42

)

Interest expense

)

Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss)

	Location of gain/(loss)	Gain/(loss) recognized in income
Derivatives not designated as hedging instruments:	recognized in income	2018		2017		2016
Foreign exchange contracts	Other income, net	$	—	$	11	$	(3	)

Debt (Tables)

12 Months Ended

Dec. 31, 2018

Debt Disclosure [Abstract]

Schedule of Debt

Short-term debt and current portion of long-term debt consists of the following:

	December 31,
	2018		2017
7.000% senior notes due 2019	$	186	$	—
Current portion of term loan due 2019		—		85
	$	186	$	85

Long-term debt consists of the following:

	December 31,
	2018		2017
Revolving $1.25 billion credit facility	$	130	$	884
Term loan due 2019		—		84
7.000% senior notes due 2019		—		186
5.750% senior notes due 2021		498		497
3.500% senior notes due 2021		448		447
2.125% senior notes due 2022 ⁽ⁱ⁾		615		644
4.625% senior notes due 2023		248		248
3.600% senior notes due 2024		645		645
4.400% senior notes due 2026		544		544
4.500% senior notes due 2028		595		—
6.125% senior notes due 2043		271		271
5.050% senior notes due 2048		395		—
	$	4,389	$	4,450

(i)	Notes issued in Euro (€540 million)

Schedule of Maturities of Long-term Debt

The following table summarizes the maturity of our debt, interest on senior notes and excludes any reduction for debt issuance costs:

	2019		2020		2021		2022		2023		Thereafter		Total
Senior notes	$	187	$	—	$	950	$	617	$	250	$	2,475	$	4,479
Interest on senior notes		191		181		153		128		119		1,019		1,791
RCF		—		—		—		130		—		—		130
Total	$	378	$	181	$	1,103	$	875	$	369	$	3,494	$	6,400

Schedule Of Debt Interest Expense

The following table shows an analysis of the interest expense for the years ended December 31:

	Years ended December 31,
	2018		2017		2016
Senior notes	$	166	$	148	$	139
Term loans		4		8		17
RCF		26		17		10
WSI revolving credit facility		—		1		2
Other⁽ⁱ⁾		12		14		16
Total interest expense	$	208	$	188	$	184

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis

The following tables present our assets and liabilities measured at fair value on a recurring basis at December 31, 2018 and December 31, 2017:

		Fair Value Measurements on a Recurring Basis at December 31, 2018
	Balance Sheet Location	Level 1		Level 2		Level 3		Total
Assets:
Available-for-sale securities:
Mutual funds / exchange traded funds	Prepaid and other current assets and other non-current assets	$	18	$	—	$	—	$	18
Derivatives:
Derivative financial instruments ⁽ⁱ⁾	Prepaid and other current assets and other non-current assets	$	—	$	5	$	—	$	5
Liabilities:
Contingent consideration:
Contingent consideration ⁽ⁱⁱ⁾	Other current liabilities and other non-current liabilities	$	—	$	—	$	51	$	51
Derivatives:
Derivative financial instruments ⁽ⁱ⁾	Other current liabilities and other non-current liabilities	$	—	$	17	$	—	$	17

		Fair Value Measurements on a Recurring Basis at December 31, 2017
	Balance Sheet Location	Level 1		Level 2		Level 3		Total
Assets:
Available-for-sale securities:
Mutual funds / exchange traded funds	Prepaid and other current assets and other non-current assets	$	40	$	—	$	—	$	40
Derivatives:
Derivative financial instruments ⁽ⁱ⁾	Prepaid and other current assets and other non-current assets	$	—	$	18	$	—	$	18
Liabilities:
Contingent consideration:
Contingent consideration ⁽ⁱⁱ⁾	Other current liabilities and other non-current liabilities	$	—	$	—	$	51	$	51
Derivatives:
Derivative financial instruments ⁽ⁱ⁾	Other current liabilities and other non-current liabilities	$	—	$	37	$	—	$	37

(i)	See Note 10 — Derivative Financial Instruments for further information on our derivative instruments.

(ii)

Schedule of Change in Fair Value of Level 3 Liabilities

The following table summarizes the change in fair value of the Level 3 liabilities:

Fair Value Measurements Using Significant Unobservable Inputs (Level 3)	December 31, 2018
Balance at December 31, 2017	$	51
Obligations assumed		2
Payments		(3	)
Realized and unrealized gains		3
Foreign exchange		(2	)
Balance at December 31, 2018	$	51

Schedule of Liabilities Whose Carrying Values Differ From the Fair Value and are Not Measured on a Recurring Basis

The following tables present our liabilities not measured at fair value on a recurring basis at December 31, 2018 and 2017:

	December 31, 2018				December 31, 2017
	Carrying Value		Fair Value		Carrying Value		Fair Value
Liabilities:
Short-term debt and current portion of long-term debt	$	186	$	191	$	85	$	85
Long-term debt	$	4,389	$	4,458	$	4,450	$	4,706

Retirement Benefits (Tables)

12 Months Ended

Dec. 31, 2018

Compensation And Retirement Disclosure [Abstract]

Schedule of Changes in Projected Benefit Obligations

The following schedules provide information concerning the defined benefit pension plans and PRW plan as of and for the years ended December 31, 2018 and 2017:

	2018												2017
	U.S.			U.K.			Other			PRW			U.S.			U.K.			Other			PRW
Change in Benefit Obligation
Benefit obligation, beginning of year	$	4,476		$	4,165		$	822		$	123		$	4,169		$	3,899		$	732		$	113
Service cost		66			18			21			1			66			32			20			—
Interest cost		140			95			18			4			139			93			17			4
Employee contributions		14			1			—			7			6			1			—			6
Actuarial (gains)/losses		(313	)		(176	)		(7	)		(3	)		293			2			5			14
Settlements		(11	)		(152	)		(26	)		—			(16	)		(138	)		(1	)		—
Curtailments		—			—			(20	)		—			—			—			—			—
Benefits paid		(185	)		(96	)		(28	)		(14	)		(181	)		(93	)		(29	)		(14	)
Plan amendments		—			40			—			(31	)		—			—			—			—
Transfers in		—			—			1			—			—			—			1			—
Foreign currency changes		—			(229	)		(53	)		—			—			369			77			—
Benefit obligation, end of year	$	4,187		$	3,666		$	728		$	87		$	4,476		$	4,165		$	822		$	123
Change in Plan Assets
Fair value of plan assets, beginning of year	$	3,654		$	4,910		$	562		$	2		$	3,280		$	4,360		$	467		$	4
Actual return on plan assets		(157	)		(69	)		(9	)		—			464			290			42			—
Employer contributions		88			85			22			6			101			66			34			6
Employee contributions		14			1			—			7			6			1			—			6
Settlements		(11	)		(152	)		(26	)		—			(16	)		(138	)		(1	)		—
Benefits paid		(185	)		(96	)		(28	)		(14	)		(181	)		(93	)		(29	)		(14	)
Transfers in		—			—			1			—			—			—			1			—
Foreign currency adjustment		—			(277	)		(36	)		—			—			424			48			—
Fair value of plan assets, end of year	$	3,403		$	4,402		$	486		$	1		$	3,654		$	4,910		$	562		$	2
Funded status at end of year	$	(784	)	$	736		$	(242	)	$	(86	)	$	(822	)	$	745		$	(260	)	$	(121	)
Accumulated Benefit Obligation	$	4,187		$	3,666		$	698		$	87		$	4,476		$	4,165		$	790		$	123
Components on the Consolidated Balance Sheet
Pension benefits assets	$	—		$	745		$	17		$	—		$	—		$	754		$	17		$	—
Current liability for pension benefits	$	(49	)	$	(1	)	$	(6	)	$	(5	)	$	(40	)	$	—		$	(6	)	$	(5	)
Non-current liability for pension benefits	$	(735	)	$	(8	)	$	(253	)	$	(81	)	$	(782	)	$	(9	)	$	(271	)	$	(116	)
	$	(784	)	$	736		$	(242	)	$	(86	)	$	(822	)	$	745		$	(260	)	$	(121	)

Schedule of Amounts Recognized in Other Comprehensive Income (Loss)

Amounts recognized in accumulated other comprehensive loss as of December 31, 2018 and 2017 consist of:

	2018										2017
	U.S.		U.K.			Other		PRW			U.S.		U.K.			Other		PRW
Net actuarial loss	$	769	$	955		$	98	$	16		$	663	$	909		$	79	$	19
Net prior service gain		—		(76	)		—		(31	)		—		(142	)		—		—
Accumulated other comprehensive loss/(income)	$	769	$	879		$	98	$	(15	)	$	663	$	767		$	79	$	19

Schedule of Benefit Obligations in Excess of Fair Value of Plan Assets

	2018						2017
	U.S.		U.K.		Other		U.S.		U.K.		Other
Projected benefit obligation at end of year	$	4,187	$	9	$	672	$	4,476	$	10	$	758
Fair value of plan assets at end of year	$	3,403	$	—	$	413	$	3,654	$	—	$	481

Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets

	2018						2017
	U.S.		U.K.		Other		U.S.		U.K.		Other
Projected benefit obligation at end of year	$	4,187	$	9	$	672	$	4,476	$	10	$	758
Accumulated benefit obligation at end of year	$	4,187	$	9	$	642	$	4,476	$	10	$	726
Fair value of plan assets at end of year	$	3,403	$	—	$	413	$	3,654	$	—	$	481

Schedule of Net Periodic Benefit Cost

	2018												2017											2016
	U.S.			U.K.			Other			PRW			U.S.			U.K.			Other			PRW		U.S.			U.K.			Other			PRW
Components of net periodic benefit (income)/cost:
Service cost	$	66		$	18		$	21		$	1		$	66		$	32		$	20		$	—	$	59		$	24		$	19		$	1
Interest cost		140			95			18			4			139			93			17			4		137			114			18			3
Expected return on plan assets		(273	)		(298	)		(31	)		—			(245	)		(284	)		(30	)		—		(240	)		(253	)		(27	)		—
Amortization of unrecognized prior service credit		—			(19	)		—			—			—			(18	)		—			—		—			(19	)		—			—
Amortization of unrecognized actuarial loss		11			45			2			—			13			53			2			—		12			42			—			—
Settlement		1			41			2			—			1			37			1			—		—			—			5			—
Curtailment gain		—			—			(16	)		—			—			—			—			—		—			—			—			—
Net periodic benefit (income)/cost	$	(55	)	$	(118	)	$	(4	)	$	5		$	(26	)	$	(87	)	$	10		$	4	$	(32	)	$	(92	)	$	15		$	4
Other changes in plan assets and benefit obligations recognized in other comprehensive loss/(income):
Net actuarial loss/(gain)	$	117		$	191		$	13		$	(3	)	$	74		$	(4	)	$	(7	)	$	14	$	238		$	323		$	62		$	4
Amortization of unrecognized actuarial loss		(11	)		(45	)		(2	)		—			(13	)		(53	)		(2	)		—		(12	)		(42	)		—			—
Prior service cost/(credit)		—			40			—			(31	)		—			—			—			—		—			—			—			—
Amortization of unrecognized prior service credit		—			19			—			—			—			18			—			—		—			19			—			—
Settlement		(1	)		(41	)		(2	)		—			(1	)		(37	)		(1	)		—		—			—			(8	)		—
Curtailment gain		—			—			16			—			—			—			—			—		—			—			—			—
Total recognized in other comprehensive loss/(income)		105			164			25			(34	)		60			(76	)		(10	)		14		226			300			54			4
Total recognized in net periodic benefit (income)/cost and other comprehensive loss/(income)	$	50		$	46		$	21		$	(29	)	$	34		$	(163	)	$	—		$	18	$	194		$	208		$	69		$	8

Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year

	For the Year Ended December 31, 2019
	U.S.		U.K			Other		PRW
Estimated net actuarial loss	$	19	$	21		$	2	$	1
Prior service credit	$	—	$	(16	)	$	—	$	(4	)

Schedule of Assumptions Used

The assumptions used to determine net periodic benefit cost for the fiscal years ended December 31, 2018, 2017, and 2016 were as follows:

	Years ended December 31,
	2018												2017												2016
	U.S.			U.K.			Other			PRW			U.S.			U.K.			Other			PRW			U.S.			U.K.			Other			PRW
Discount rate - PBO		3.6	%		2.6	%		2.6	%		3.5	%		4.0	%		2.6	%		2.7	%		4.0	%		4.2	%		3.8	%		3.2	%		4.2	%
Discount rate - service cost		3.5	%		2.7	%		2.9	%		3.5	%		3.9	%		2.6	%		3.0	%		3.9	%		3.9	%		3.8	%		3.4	%		4.1	%
Discount rate - interest cost on service cost		3.1	%		2.5	%		2.7	%		3.2	%		3.2	%		2.4	%		2.8	%		3.5	%		3.2	%		3.8	%		3.1	%		3.5	%
Discount rate - interest cost on PBO		3.2	%		2.3	%		2.3	%		3.1	%		3.4	%		2.3	%		2.3	%		3.3	%		3.4	%		3.4	%		2.8	%		3.3	%
Expected long-term rate of return on assets		7.6	%		6.2	%		5.7	%		2.0	%		7.6	%		6.3	%		6.1	%		2.0	%		7.6	%		6.2	%		6.1	%		2.0	%
Rate of increase in compensation levels		4.3	%		3.0	%		2.3	%	N/A				4.3	%		3.2	%		2.3	%	N/A				4.3	%		3.2	%		2.3	%	N/A
Healthcare cost trend
Initial rate											6.5	%											7.0	%											7.0	%
Ultimate rate											5.0	%											5.0	%											5.0	%
Year reaching ultimate rate										2022												2022												2022

The following tables present the assumptions used in the valuation to determine the projected benefit obligation for the fiscal years ended December 31, 2018 and 2017:

	December 31, 2018												December 31, 2017
	U.S.			U.K.			Other			PRW			U.S.			U.K.			Other			PRW
Discount rate		4.2	%		2.8	%		2.8	%		4.2	%		3.6	%		2.6	%		2.6	%		3.5	%
Rate of increase in compensation levels		4.3	%		3.0	%		2.3	%	N/A				4.3	%		3.0	%		2.3	%	N/A

Schedule of Allocation of Plan Assets

The Company’s pension plan asset target allocations as of December 31, 2018 were as follows:

	U.S.						U.K.									Canada			Germany			Ireland
Asset Category	Willis			Willis Towers Watson			Willis			Towers Watson			Miller			Towers Watson			Towers Watson			Willis			Towers Watson
Equity securities		30	%		23	%		23	%		7	%		19	%		40	%		34	%		30	%		40	%
Debt securities		44	%		43	%		58	%		25	%		21	%		50	%		59	%		29	%		30	%
Real estate		11	%		6	%		2	%		1	%		—	%		5	%		—	%		3	%		—	%
Other		15	%		28	%		17	%		67	%		60	%		5	%		7	%		38	%		30	%
Total		100	%		100	%		100	%		100	%		100	%		100	%		100	%		100	%		100	%

The fair values of our U.S. plan assets by asset category at December 31, 2018 and 2017 are as follows:

	December 31, 2018								December 31, 2017
	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
Asset category:
Cash	$	6	$	—	$	—	$	6	$	10	$	—	$	—	$	10
Short-term securities		—		78		—		78		—		283		—		283
Equity securities		156		—		—		156		202		—		—		202
Government bonds		2		—		—		2		10		—		—		10
Corporate bonds		—		354		—		354		—		193		—		193
Other fixed income		—		—		—		—		—		20		—		20
Pooled / commingled funds		—		—		—		1,467		—		—		—		1,922
Mutual funds		—		—		—		—		1		—		—		1
Private equity		—		—		—		357		—		—		—		287
Hedge funds		—		—		—		984		—		—		—		724
Total assets	$	164	$	432	$	—	$	3,404	$	223	$	496	$	—	$	3,652

The fair values of our U.K. plan assets by asset category at December 31, 2018 and 2017 are as follows:

	December 31, 2018									December 31, 2017
	Level 1		Level 2			Level 3		Total		Level 1		Level 2		Level 3		Total
Asset category:
Cash	$	229	$	—		$	—	$	229	$	92	$	—	$	—	$	92
Equity securities		—		—			—		—		24		—		—		24
Government bonds		1,804		—			—		1,804		1,841		—		—		1,841
Corporate bonds		—		297			—		297		—		224		—		224
Other fixed income		—		248			—		248		—		246		—		246
Pooled / commingled funds		—		—			—		934		—		—		—		2,294
Mutual funds		—		—			—		16		—		—		—		8
Private equity		—		—			—		33		—		—		—		32
Derivatives		—		96			—		96		—		102		—		102
Real estate		—		—			—		184		—		—		—		218
Hedge funds		—		—			—		1,232		—		—		—		393
Total assets	$	2,033	$	641		$	—	$	5,073	$	1,957	$	572	$	—	$	5,474

Liability category:
Repurchase agreements		—		684			—		684		—		549		—		549
Derivatives		—		—			—		—		—		16		—		16
Net assets/(liabilities)	$	2,033	$	(43	)	$	—	$	4,389	$	1,957	$	7	$	—	$	4,909

The fair values of our Other plan assets by asset category at December 31, 2018 and 2017 are as follows:

	December 31, 2018								December 31, 2017
	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
Asset category:
Cash	$	1	$	—	$	—	$	1	$	5	$	—	$	—	$	5
Pooled / commingled funds		—		—		—		294		—		—		—		327
Mutual funds		—		—		—		185		—		—		—		209
Hedge funds		—		—		—		4		—		—		—		—
Insurance contracts		—		—		2		2		—		—		19		19
Total assets	$	1	$	—	$	2	$	486	$	5	$	—	$	19	$	560

Schedule of Net Plan Investments Reconciliation To Total Fair Value Of Plan Assets

The following table reconciles the net plan investments to the total fair value of the plan assets:

	December 31,
	2018			2017
Net assets held in investments	$	8,279		$	9,121
PRW plan assets		1			2
Net (payable)/receivable for investments purchased		(1	)		2
Dividend and interest receivable		1			3
Other adjustments		12			—
Fair value of plan assets	$	8,292		$	9,128

Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets

The following table sets forth a summary of changes in the fair value of the plans’ Level 3 assets for the fiscal year ended December 31, 2018:

	Level 3 Roll Forward
Beginning balance at December 31, 2017	$	19
Plan termination	$	(17	)
Foreign exchange		—
Ending balance at December 31, 2018	$	2

Schedule of Projected Pension Contributions

	2019 (Projected)		2018 (Actual)		2017 (Actual)
U.S.	$	60	$	50	$	50
U.K.	$	75	$	84	$	65
Other	$	23	$	14	$	13

Schedule of Expected Benefit Payments

Expected benefit payments from our defined benefit pension plans to current plan participants, including the effects of their expected future service, as appropriate, are as follows:

	Benefit Payments
Fiscal Year	U.S.		U.K.		Other		PRW		Total
2019	$	263	$	109	$	28	$	13	$	413
2020		250		107		25		10		392
2021		263		116		25		11		415
2022		272		119		26		11		428
2023		280		127		27		11		445
Years 2024 – 2028		1,435		735		160		60		2,390
	$	2,763	$	1,313	$	291	$	116	$	4,483

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2018

Commitments And Contingencies Disclosure [Abstract]

Future Minimum Rental Commitments Under all Non-Cancellable Operating Lease Agreements

As of December 31, 2018, the aggregate future minimum rental commitments under all non-cancellable operating lease agreements are as follows:

	Gross rental commitments		Rentals from subleases			Net rental commitments
2019	$	197	$	(11	)	$	186
2020		180		(11	)		169
2021		159		(8	)		151
2022		142		(2	)		140
2023		131		(2	)		129
Thereafter		542		(8	)		534
Total	$	1,351	$	(42	)	$	1,309

Supplementary Information for Certain Balance Sheet Accounts Supplementary Information for Certain Balance Sheet Accounts (Tables)

12 Months Ended

Dec. 31, 2018

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Schedule of Prepaid and Other Current Asset

Prepaid and other current assets consist of the following:

	December 31, 2018		December 31, 2017
Prepayments and accrued income	$	136	$	132
Deferred contract costs		102		—
Derivatives and investments		25		29
Deferred compensation plan assets		18		21
Retention incentives		5		7
Corporate income and other taxes		61		170
Other current assets		57		71
Total prepaid and other current assets	$	404	$	430

Schedule of Other Non-current Asset

Other non-current assets consist of the following:

	December 31, 2018		December 31, 2017
Prepayments and accrued income	$	14	$	18
Deferred contract costs		46		—
Deferred compensation plan assets		125		135
Deferred tax assets		59		46
Accounts receivable, net		20		33
Other investments		7		26
Other non-current assets		196		189
Total other non-current assets	$	467	$	447

Schedule of Accounts Payable and Accrued Liabilities

Deferred revenue and accrued expenses consist of the following:

	December 31, 2018		December 31, 2017
Accounts payable, accrued liabilities and deferred income	$	691	$	772
Discretionary compensation		321		313
Accrued compensation		437		439
Accrued vacation		111		93
Other employee-related liabilities		87		94
Total deferred revenue and accrued expenses	$	1,647	$	1,711

Schedule of Other Current Liabilities

Other current liabilities consist of the following:

	December 31, 2018		December 31, 2017
Accounts payable	$	163	$	136
Income and other taxes payable		129		90
Contingent and deferred consideration on acquisitions		61		55
Payroll-related liabilities		210		209
Derivatives		13		32
Third party commissions		169		172
Other current liabilities		119		110
Total other current liabilities	$	864	$	804

Provisions for Liabilities

Provision for liabilities consists of the following:

	December 31, 2018		December 31, 2017
Claims, lawsuits and other proceedings	$	455	$	474
Other provisions		85		84
Total provision for liabilities	$	540	$	558

Schedule of Other Non-current Liabilities

Other non-current liabilities consist of the following:

	December 31, 2018		December 31, 2017
Incentives from lessors	$	120	$	138
Deferred compensation plan liability		125		135
Contingent and deferred consideration on acquisitions		22		41
Liabilities for uncertain tax positions		46		60
Lease-related liabilities		29		28
Other non-current liabilities		87		142
Total other non-current liabilities	$	429	$	544

Other Income, Net (Tables)

12 Months Ended

Dec. 31, 2018

Other Income And Expenses [Abstract]

Schedule of Other Nonoperating Income

Other income, net consists of the following:

	Years ended December 31,
	2018			2017			2016
(Loss)/gain on disposal of operations	$	(9	)	$	13		$	2
Net periodic pension and postretirement benefit credits ⁽ⁱ⁾		280			222			203
Interest in earnings of associates ⁽ⁱⁱ⁾		3			3			2
Impact of Venezuelan currency devaluation		—			(2	)		—
Foreign exchange loss		(24	)		(72	)		(29	)
Other income, net	$	250		$	164		$	178

(i)

(ii)	Beginning in 2018, the Company retrospectively reclassified the pre-tax effect of its interest in earnings of associates from its own line item to other income, net within its consolidated statements of comprehensive income.

Accumulated Other Comprehensive Loss (Tables)

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

Comprehensive Income (Loss)

The components of other comprehensive (loss)/income are as follows:

	December 31, 2018									December 31, 2017									December 31, 2016
	Before tax amount			Tax			Net of tax amount			Before tax amount			Tax			Net of tax amount			Before tax amount			Tax		Net of tax amount
Other comprehensive (loss)/income:
Foreign currency translation	$	(251	)	$	—		$	(251	)	$	295		$	—		$	295		$	(353	)	$	—	$	(353	)
Defined pension and post-retirement benefits		(258	)		59			(199	)		3			11			14			(553	)		114		(439	)
Derivative instruments		5			(3	)		2			90			(15	)		75			(87	)		12		(75	)
Other comprehensive (loss)/income		(504	)		56			(448	)		388			(4	)		384			(993	)		126		(867	)
Less: Other comprehensive (income)/loss attributable to non-controlling interests		—			—			—			(13	)		—			(13	)		20			—		20
Other comprehensive (loss)/income attributable to Willis Towers Watson	$	(504	)	$	56		$	(448	)	$	375		$	(4	)	$	371		$	(973	)	$	126	$	(847	)

Schedule of Accumulated Other Comprehensive Income (Loss)

	Foreign currency translation ⁽ⁱ⁾			Cash flow hedges ⁽ⁱ⁾			Defined pension and post- retirement benefit costs ⁽ⁱⁱ⁾			Total
Balance, January 1, 2016	$	(314	)	$	(10	)	$	(713	)	$	(1,037	)
Other comprehensive loss before reclassifications		(336	)		(110	)		(483	)		(929	)
Loss reclassified from accumulated other comprehensive loss (net of income tax benefit of $5)		—			38			44			82
Net other comprehensive loss		(336	)		(72	)		(439	)		(847	)
Balance, December 31, 2016	$	(650	)	$	(82	)	$	(1,152	)	$	(1,884	)
Other comprehensive income/(loss) before reclassifications		285			28			(26	)		287
Loss reclassified from accumulated other comprehensive loss (net of income tax benefit of $18)		—			44			40			84
Net other comprehensive income		285			72			14			371
Balance, December 31, 2017	$	(365	)	$	(10	)	$	(1,138	)	$	(1,513	)
Other comprehensive income/(loss) before reclassifications		(251	)		(22	)		(241	)		(514	)
Loss reclassified from accumulated other comprehensive loss (net of income tax benefit of $17)		—			24			42			66
Net other comprehensive loss		(251	)		2			(199	)		(448	)
Balance, December 31, 2018	$	(616	)	$	(8	)	$	(1,337	)	$	(1,961	)

(i)

(ii)	Reclassification adjustments from accumulated other comprehensive loss are included in the computation of net periodic pension cost (see Note 13 — Retirement Benefits). These components are included in Other income, net in the accompanying consolidated statements of comprehensive income.

Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Assumptions Used on Options

	Years ended December 31,
	2017			2016
Expected volatility		19.8	%		21.0	%
Expected dividends		1.4	%		1.5	%
Expected life (years)		4.2			2.7
Risk-free interest rate		1.6	%		0.7	%

The assumptions noted in the table below represent the weighted-average of each assumption for each grant during the year.

	Years ended December 31,
	2018			2017			2016
Expected volatility		17.9	%		20.2	%		20.3	%
Expected dividend yield		—	%		—	%		—	%
Expected life (years)		2.5			2.4			2.6
Risk-free interest rate		2.6	%		1.4	%		0.8	%

Schedule of Share-based Compensation, Stock Options, Activity

A summary of option activity under the plans at December 31, 2018, and changes during the year then ended is presented below:

	Options (thousands)		Weighted- Average Exercise Price ⁽ⁱ⁾		Weighted- Average Remaining Contractual Term	Aggregate Intrinsic Value
Time-based stock options
Balance as of December 31, 2017		754	$	103.85
Granted		—	$	—
Exercised		294	$	107.96
Expired		11	$	102.19
Balance as of December 31, 2018		449	$	101.21	3 years	$	23
Options vested or expected to vest at December 31, 2018		445	$	100.97	3 years	$	23
Options exercisable at December 31, 2018		329	$	99.48	3 years	$	17
Performance-based stock options
Balance as of December 31, 2017		680	$	106.42
Granted		—	$	—
Exercised		138	$	96.02
Forfeited		—	$	—
Balance as of December 31, 2018		542	$	110.55	3 years	$	22
Options vested or expected to vest at December 31, 2018		542	$	110.55	3 years	$	22
Options exercisable at December 31, 2018		542	$	110.55	3 years	$	22

Schedule of Share-based Compensation, Restricted Stock Units Award Activity

Award Activity

A summary of time-based and performance-based RSU activity under the plans at December 31, 2018, and changes during the year then ended, is presented below:

	Shares (thousands)		Weighted- Average Grant Date Fair Value
Nonvested shares (time-based RSUs)
Balance as of December 31, 2017		143	$	122.27
Granted		51	$	153.58
Vested		165	$	122.61
Forfeited		10	$	117.09
Balance as of December 31, 2018		19	$	141.19
Nonvested shares (performance-based RSUs)
Balance as of December 31, 2017		881	$	90.61
Granted		141	$	204.13
Vested		250	$	125.75
Forfeited		14	$	118.94
Balance as of December 31, 2018		758	$	91.02

Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2018

Earnings Per Share [Abstract]

Schedule of Basic and Diluted Earnings Per Share

Basic and diluted earnings per share are as follows:

	Years ended December 31,
	2018			2017			2016
Net income attributable to Willis Towers Watson	$	695		$	568		$	420

Basic weighted-average number of shares outstanding		131			135			137
Dilutive effect of potentially issuable shares		1			1			1
Diluted weighted-average number of shares outstanding		132			136			138

Basic earnings per share	$	5.29		$	4.21		$	3.07
Dilutive effect of potentially issuable shares		(0.02	)		(0.03	)		(0.03	)
Diluted earnings per share	$	5.27		$	4.18		$	3.04

Supplemental Disclosures of Cash Flow Information (Tables)

12 Months Ended

Dec. 31, 2018

Supplemental Cash Flow Elements [Abstract]

Supplemental Disclosures Regarding Cash Flow Information and Non-cash Flow Investing and Financing Activities

Supplemental disclosures regarding cash flow information and non-cash investing and financing activities are as follows:

	Years Ended December 31,
	2018		2017		2016
Supplemental disclosures of cash flow information:
Cash payments for income taxes, net	$	178	$	203	$	158
Cash payments for interest	$	176	$	169	$	143
Cash acquired	$	13	$	—	$	476
Supplemental disclosures of non-cash investing and financing activities:
Issuance of shares and assumed awards in connection with the Merger	$	—	$	—	$	8,723
Fair value of deferred and contingent consideration related to acquisitions	$	36	$	—	$	—

Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Data

Quarterly financial data for 2018 and 2017 were as follows:

	Three Months Ended
	March 31,		June 30,		September 30,			December 31,
2018
Revenue	$	2,292	$	1,990	$	1,859		$	2,372
Total costs of providing services	$	2,033	$	1,927	$	1,842		$	1,902
Income from operations	$	259	$	63	$	17		$	470
Net income	$	221	$	65	$	46		$	383
Net income attributable to Willis Towers Watson	$	215	$	58	$	44		$	378
Earnings per share
— Basic	$	1.62	$	0.44	$	0.34		$	2.91
— Diluted	$	1.61	$	0.44	$	0.33		$	2.89
2017
Revenue	$	2,319	$	1,953	$	1,852		$	2,078
Total costs of providing services	$	1,918	$	1,892	$	1,878		$	1,998
Income/(loss) from operations	$	401	$	61	$	(26	)	$	80
Net income/(loss)	$	352	$	41	$	(54	)	$	253
Net income/(loss) attributable to Willis Towers Watson	$	344	$	33	$	(54	)	$	245
Earnings/(loss) per share
— Basic	$	2.51	$	0.24	$	(0.40	)	$	1.85
— Diluted	$	2.50	$	0.24	$	(0.40	)	$	1.84

Financial Information for Issuers and Other Guarantor Subsidiaries (Tables)

12 Months Ended

Dec. 31, 2018

Condensed Financial Information Of Parent Company Only Disclosure [Abstract]

Condensed Consolidating Statement of Comprehensive Income

	Year ended December 31, 2018
	Willis Towers Watson plc			Willis North America			Trinity Acquisition plc			Other guarantors			Non- guarantors			Eliminations			Consolidated
Revenue	$	—		$	34		$	—		$	—		$	8,479		$	—		$	8,513
Costs of providing services
Salaries and benefits		2			68			—			—			5,053			—			5,123
Other operating expenses		3			38			1			165			1,430			—			1,637
Depreciation		—			—			—			4			204			—			208
Amortization		—			—			—			3			534			(3	)		534
Transaction and integration expenses		—			8			—			1			193			—			202
Total costs of providing services		5			114			1			173			7,414			(3	)		7,704
(Loss)/income from operations		(5	)		(80	)		(1	)		(173	)		1,065			3			809
Intercompany income/(expense)		—			56			124			356			(536	)		—			—
Interest expense		(30	)		(58	)		(104	)		—			(16	)		—			(208	)
Other income, net		—			—			—			2			1,540			(1,292	)		250
(LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES		(35	)		(82	)		19			185			2,053			(1,289	)		851
(Provision for)/benefit from income taxes		—			(1	)		(3	)		41			(173	)		—			(136	)
Equity account for subsidiaries		730			124			437			498			—			(1,789	)		—
NET INCOME		695			41			453			724			1,880			(3,078	)		715
Income attributable to non-controlling interests		—			—			—			—			(20	)		—			(20	)
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON	$	695		$	41		$	453		$	724		$	1,860		$	(3,078	)	$	695

Comprehensive income/(loss) before non- controlling interests	$	247		$	(88	)	$	14		$	286		$	1,470		$	(1,662	)	$	267
Comprehensive income attributable to non- controlling interests		—			—			—			—			(20	)		—			(20	)
Comprehensive income/(loss) attributable to Willis Towers Watson	$	247		$	(88	)	$	14		$	286		$	1,450		$	(1,662	)	$	247

Condensed Consolidating Statement of Comprehensive Income

	Year ended December 31, 2017
	Willis Towers Watson plc			Willis North America			Trinity Acquisition plc			Other guarantors			Non- guarantors			Eliminations			Consolidated
Revenue	$	—		$	19		$	—		$	—		$	8,183		$	—		$	8,202
Costs of providing services
Salaries and benefits		4			48			—			—			4,915			—			4,967
Other operating expenses		3			20			1			91			1,419			—			1,534
Depreciation		—			—			—			6			197			—			203
Amortization		—			—			—			3			581			(3	)		581
Restructuring costs		—			15			—			8			109			—			132
Transaction and integration expenses		—			19			—			73			177			—			269
Total costs of providing services		7			102			1			181			7,398			(3	)		7,686
(Loss)/income from operations		(7	)		(83	)		(1	)		(181	)		785			3			516
Intercompany income/(expense)		—			34			123			350			(507	)		—			—
Interest expense		(30	)		(35	)		(103	)		—			(20	)		—			(188	)
Other income, net		35			—			—			—			367			(238	)		164
(LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES		(2	)		(84	)		19			169			625			(235	)		492
(Provision for)/benefit from income taxes		—			(29	)		(2	)		53			78			—			100
Equity account for subsidiaries		570			171			290			370			—			(1,401	)		—
NET INCOME		568			58			307			592			703			(1,636	)		592
Income attributable to non-controlling interests		—			—			—			—			(24	)		—			(24	)
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON	$	568		$	58		$	307		$	592		$	679		$	(1,636	)	$	568

Comprehensive income before non- controlling interests	$	939		$	197		$	663		$	952		$	1,051		$	(2,826	)	$	976
Comprehensive income attributable to non- controlling interests		—			—			—			—			(37	)		—			(37	)
Comprehensive income attributable to Willis Towers Watson	$	939		$	197		$	663		$	952		$	1,014		$	(2,826	)	$	939

Condensed Consolidating Statement of Comprehensive Income

	Year ended December 31, 2016
	Willis Towers Watson plc			Willis North America			Trinity Acquisition plc			Other guarantors			Non- guarantors			Eliminations			Consolidated
Revenue	$	—		$	19		$	—		$	2		$	7,866		$	—			7,887
Costs of providing services
Salaries and benefits		2			15			—			1			4,831			—			4,849
Other operating expenses		3			88			—			112			1,348			—			1,551
Depreciation		—			14			—			5			159			—			178
Amortization		—			—			—			—			591			—			591
Restructuring costs		—			39			—			29			125			—			193
Transaction and integration expenses		1			26			—			16			134			—			177
Total costs of providing services		6			182			—			163			7,188			—			7,539
(Loss)/income from operations		(6	)		(163	)		-			(161	)		678			—			348
Intercompany income/(expense)		—			109			106			320			(535	)		—			—
Interest expense		(32	)		(39	)		(90	)		—			(23	)		—			(184	)
Other income, net		—			—			—			2			176			—			178
(LOSS)/INCOME FROM OPERATIONS BEFORE INCOME TAXES		(38	)		(93	)		16			161			296			—			342
Benefit from/(provision for) income taxes		—			86			(3	)		39			(26	)		—			96
Equity account for subsidiaries		458			157			151			247			—			(1,013	)		—
NET INCOME		420			150			164			447			270			(1,013	)		438
Income attributable to non-controlling interests		—			—			—			—			(18	)		—			(18	)
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON	$	420		$	150		$	164		$	447		$	252		$	(1,013	)	$	420

Comprehensive loss before non- controlling interests	$	(427	)	$	(266	)	$	(656	)	$	(381	)	$	(549	)	$	1,850		$	(429	)
Comprehensive loss attributable to non- controlling interests		—			—			—			—			2			—			2
Comprehensive loss attributable to Willis Towers Watson	$	(427	)	$	(266	)	$	(656	)	$	(381	)	$	(547	)	$	1,850		$	(427	)

Condensed Consolidating Balance Sheet

	As of December 31, 2018
	Willis Towers Watson plc		Willis North America		Trinity Acquisition plc		Other guarantors		Non- guarantors		Eliminations			Consolidated
ASSETS
Cash and cash equivalents	$	—	$	—	$	—	$	—	$	1,033	$	—		$	1,033
Fiduciary assets		—		—		—		—		12,604		—			12,604
Accounts receivable, net		—		24		—		—		2,355		—			2,379
Prepaid and other current assets		—		311		1		33		357		(298	)		404
Total current assets		—		335		1		33		16,349		(298	)		16,420
Intercompany receivables, net		4,755		—		1,355		—		—		(6,110	)		—
Fixed assets, net		—		—		—		16		926		—			942
Goodwill		—		—		—		—		10,465		—			10,465
Other intangible assets, net		—		—		—		58		3,318		(58	)		3,318
Pension benefits assets		—		—		—		—		773		—			773
Other non-current assets		—		92		2		49		452		(128	)		467
Total non-current assets		4,755		92		1,357		123		15,934		(6,296	)		15,965
Investments in subsidiaries		5,691		6,649		2,677		8,108		—		(23,125	)		—
TOTAL ASSETS	$	10,446	$	7,076	$	4,035	$	8,264	$	32,283	$	(29,719	)	$	32,385
LIABILITIES AND EQUITY
Fiduciary liabilities	$	—	$	—	$	—	$	—	$	12,604	$	—		$	12,604
Deferred revenue and accrued expenses		1		2		—		3		1,641		—			1,647
Short-term debt and current portion of long-term debt		—		186		—		—		—		—			186
Other current liabilities		95		38		33		13		935		(250	)		864
Total current liabilities		96		226		33		16		15,180		(250	)		15,301
Intercompany payables, net		—		902		—		4,691		517		(6,110	)		—
Long-term debt		498		1,635		2,256		—		—		—			4,389
Liability for pension benefits		—		—		—		—		1,170		—			1,170
Deferred tax liabilities		—		—		—		—		688		(129	)		559
Provision for liabilities		—		120		—		—		420		—			540
Other non-current liabilities		—		13		—		5		411		—			429
Total non-current liabilities		498		2,670		2,256		4,696		3,206		(6,239	)		7,087
TOTAL LIABILITIES		594		2,896		2,289		4,712		18,386		(6,489	)		22,388
REDEEMABLE NON-CONTROLLING INTEREST		—		—		—		—		26		—			26
EQUITY
Total Willis Towers Watson shareholders’ equity		9,852		4,180		1,746		3,552		13,752		(23,230	)		9,852
Non-controlling interests		—		—		—		—		119		—			119
Total equity		9,852		4,180		1,746		3,552		13,871		(23,230	)		9,971
TOTAL LIABILITIES AND EQUITY	$	10,446	$	7,076	$	4,035	$	8,264	$	32,283	$	(29,719	)	$	32,385

Condensed Consolidating Balance Sheet

	As of December 31, 2017
	Willis Towers Watson plc		Willis North America		Trinity Acquisition plc		Other guarantors		Non guarantors		Eliminations			Consolidated
ASSETS
Cash and cash equivalents	$	2	$	—	$	—	$	1	$	1,027	$	—		$	1,030
Fiduciary assets		—		—		—		—		12,155		—			12,155
Accounts receivable, net		—		4		—		—		2,242		—			2,246
Prepaid and other current assets		—		267		1		44		264		(146	)		430
Total current assets		2		271		1		45		15,688		(146	)		15,861
Intercompany receivables, net		6,202		—		2,501		—		—		(8,703	)		-
Fixed assets, net		—		—		—		25		960		—			985
Goodwill		—		—		—		—		10,519		—			10,519
Other intangible assets, net		—		—		—		60		3,882		(60	)		3,882
Pension benefits assets		—		—		—		—		764		—			764
Other non-current assets		—		115		3		31		388		(90	)		447
Total non-current assets		6,202		115		2,504		116		16,513		(8,853	)		16,597
Investments in subsidiaries		4,506		6,125		1,918		8,425		—		(20,974	)		—
TOTAL ASSETS	$	10,710	$	6,511	$	4,423	$	8,586	$	32,201	$	(29,973	)	$	32,458
LIABILITIES AND EQUITY
Fiduciary liabilities	$	—	$	—	$	—	$	—	$	12,155	$	—		$	12,155
Deferred revenue and accrued expenses		—		19		—		7		1,685		—			1,711
Short-term debt and current portion of long-term debt		—		—		—		—		85		—			85
Other current liabilities		87		83		33		27		724		(150	)		804
Total current liabilities		87		102		33		34		14,649		(150	)		14,755
Intercompany payables, net		—		787		—		3,895		4,021		(8,703	)		—
Long-term debt		497		986		2,883		—		84		—			4,450
Liability for pension benefits		—		—		—		—		1,259		—			1,259
Deferred tax liabilities		—		—		—		—		704		(89	)		615
Provision for liabilities		—		120		—		—		438		—			558
Other non-current liabilities		—		19		—		5		520		—			544
Total non-current liabilities		497		1,912		2,883		3,900		7,026		(8,792	)		7,426
TOTAL LIABILITIES		584		2,014		2,916		3,934		21,675		(8,942	)		22,181
REDEEMABLE NON-CONTROLLING INTEREST		—		—		—		—		28		—			28
EQUITY
Total Willis Towers Watson shareholders’ equity		10,126		4,497		1,507		4,652		10,375		(21,031	)		10,126
Non-controlling interests		—		—		—		—		123		—			123
Total equity		10,126		4,497		1,507		4,652		10,498		(21,031	)		10,249
TOTAL LIABILITIES AND EQUITY	$	10,710	$	6,511	$	4,423	$	8,586	$	32,201	$	(29,973	)	$	32,458

Condensed Consolidating Statement of Cash Flows

	Year ended December 31, 2018
	Willis Towers Watson plc			Willis North America			Trinity Acquisition plc			Other guarantors			Non- guarantors			Eliminations			Consolidated
NET CASH (USED IN)/FROM OPERATING ACTIVITIES	$	(537	)	$	153		$	355		$	(792	)	$	3,196		$	(1,087	)	$	1,288
CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES
Additions to fixed assets and software for internal use		—			—			—			(4	)		(264	)		—			(268	)
Capitalized software costs		—			—			—			—			(54	)		—			(54	)
Acquisitions of operations, net of cash acquired		—			—			—			—			(36	)		—			(36	)
Net proceeds from sale of operations		—			—			—			—			4			—			4
Other, net		—			—			—			—			13			—			13
Proceeds from/(repayments of) intercompany investing activities, net		1,398			369			92			356			(2,673	)		458			—
Net cash from/(used in) investing activities	$	1,398		$	369		$	92		$	352		$	(3,010	)	$	458		$	(341	)
CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES
Net payments on revolving credit facility		—			(155	)		(599	)		—			—			—			(754	)
Senior notes issued		—			998			—			—			—			—			998
Debt issuance costs		—			(8	)		—			—			—			—			(8	)
Repayments of debt		—			—			—			—			(170	)		—			(170	)
Repurchase of shares		(602	)		—			—			—			—			—			(602	)
Proceeds from issuance of shares		45			—			—			—			—			—			45
Payments of deferred and contingent consideration related to acquisitions		—			—			—			—			(50	)		—			(50	)
Cash paid for employee taxes on withholding shares		—			—			—			—			(30	)		—			(30	)
Dividends paid		(306	)		—			(686	)		(150	)		(251	)		1,087			(306	)
Acquisitions of and dividends paid to non- controlling interests		—			—			—			—			(26	)		—			(26	)
(Repayments of)/proceeds from intercompany financing activities, net		—			(1,357	)		838			589			388			(458	)		—
Net cash (used in)/from financing activities	$	(863	)	$	(522	)	$	(447	)	$	439		$	(139	)	$	629		$	(903	)
(DECREASE)/INCREASE IN CASH AND CASH EQUIVALENTS		(2	)		—			—			(1	)		47			—			44
Effect of exchange rate changes on cash and cash equivalents		—			—			—			—			(41	)		—			(41	)
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR		2			—			—			1			1,027			—			1,030
CASH AND CASH EQUIVALENTS, END OF YEAR	$	—		$	—		$	—		$	—		$	1,033		$	—		$	1,033

Condensed Consolidating Statement of Cash Flows

	Year ended December 31, 2017
	Willis Towers Watson plc			Willis North America			Trinity Acquisition plc			Other guarantors			Non- guarantors			Eliminations			Consolidated
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	$	743		$	114		$	29		$	(696	)	$	939		$	(267	)	$	862
CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES
Additions to fixed assets and software for internal use		—			—			—			(8	)		(292	)		—			(300	)
Capitalized software costs		—			—			—			—			(75	)		—			(75	)
Acquisitions of operations, net of cash acquired		—			—			—			—			(13	)		—			(13	)
Net proceeds from sale of operations		—			—			—			—			57			—			57
Other, net		—			—			—			—			(4	)		—			(4	)
Proceeds from/(repayments of) intercompany investing activities, net		1,042			(55	)		(1,600	)		277			(485	)		821			—
(Increase)/decrease in investment in subsidiaries		(1,035	)		(115	)		(148	)		833			465			—			—
Net cash from/(used in) investing activities	$	7		$	(170	)	$	(1,748	)	$	1,102		$	(347	)	$	821		$	(335	)
CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES
Net borrowings on revolving credit facility		—			155			487			—			—			—			642
Senior notes issued		—			649			—			—			—			—			649
Proceeds from issuance of other debt		—			—			—			—			32			—			32
Debt issuance costs		—			(5	)		(4	)		—			—			—			(9	)
Repayments of debt		—			(394	)		(220	)		—			(120	)		—			(734	)
Repurchase of shares		(532	)		—			—			—			—			—			(532	)
Proceeds from issuance of shares		61			—			—			—			—			—			61
Payments related to share cancellation		—			—			—			—			(177	)		—			(177	)
Payments of deferred and contingent consideration related to acquisitions		—			—			—			—			(65	)		—			(65	)
Cash paid for employee taxes on withholding shares		—			—			—			—			(18	)		—			(18	)
Dividends paid		(277	)		(58	)		—			(58	)		(151	)		267			(277	)
Acquisitions of and dividends paid to non- controlling interests		—			—			—			—			(51	)		—			(51	)
(Repayments of)/proceeds from intercompany financing activities, net		—			(291	)		1,456			(347	)		3			(821	)		—
Net cash (used in)/from financing activities	$	(748	)	$	56		$	1,719		$	(405	)	$	(547	)	$	(554	)	$	(479	)
INCREASE IN CASH AND CASH EQUIVALENTS		2			—			—			1			45			—			48
Effect of exchange rate changes on cash and cash equivalents		—			—			—			—			112			—			112
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR		—			—			—			—			870			—			870
CASH AND CASH EQUIVALENTS, END OF YEAR	$	2		$	—		$	—		$	1		$	1,027		$	—		$	1,030

Condensed Consolidating Statement of Cash Flows

	Year ended December 31, 2016
	Willis Towers Watson plc			Willis North America			Trinity Acquisition plc			Other guarantors			Non- guarantors			Eliminations			Consolidated
NET CASH FROM/(USED IN) OPERATING ACTIVITIES	$	(20	)	$	(83	)	$	152		$	440		$	1,114		$	(670	)	$	933
CASH FLOWS FROM/(USED IN) INVESTING ACTIVITIES
Additions to fixed assets and software for internal use		—			(12	)		—			(79	)		(221	)		94			(218	)
Capitalized software costs		—			—			—			—			(85	)		—			(85	)
Acquisitions of operations, net of cash acquired		—			—			—			—			476			—			476
Net proceeds from sale of operations		—			—			—			—			(4	)		3			(1	)
Other, net		—			33			—			—			20			(30	)		23
Proceeds from/(repayments of) intercompany investing activities, net		(3,751	)		—			(547	)		(3,405	)		(739	)		8,442			—
Decrease/(increase) in investment in subsidiaries		4,600			—			—			(1,000	)		(3,600	)		—			—
Net cash from/(used in) investing activities	$	849		$	21		$	(547	)	$	(4,484	)	$	(4,153	)	$	8,509		$	195
CASH FLOWS (USED IN)/FROM FINANCING ACTIVITIES
Net payments on revolving credit facility		—			—			(237	)		—			—			—			(237	)
Senior notes issued		—			—			1,606			—			—			—			1,606
Proceeds from issuance of other debt		—			—			400			—			4			—			404
Debt issuance costs		—			—			(14	)		—			—			—			(14	)
Repayments of debt		(300	)		—			(1,037	)		—			(564	)		—			(1,901	)
Repurchase of shares		(396	)		—			—			—			—			—			(396	)
Proceeds from issuance of shares		63			—			—			—			—			—			63
Payments of deferred and contingent consideration related to acquisitions		—			—			—			—			(67	)		—			(67	)
Cash paid for employee taxes on withholding shares		—			—			—			—			(13	)		—			(13	)
Dividends paid		(199	)		(49	)		(302	)		(162	)		(90	)		603			(199	)
Acquisitions of and dividends paid to non- controlling interests		—			—			—			—			(21	)		—			(21	)
Proceeds from/(repayments of) intercompany financing activities, net		—			111			(21	)		4,204			4,148			(8,442	)		—
Net cash (used in)/from financing activities	$	(832	)	$	62		$	395		$	4,042		$	3,397		$	(7,839	)	$	(775	)
(DECREASE)/INCREASE IN CASH AND CASH EQUIVALENTS		(3	)		—			—			(2	)		358			—			353
Effect of exchange rate changes on cash and cash equivalents		—			—			—			—			(15	)		—			(15	)
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR		3			—			—			2			527			—			532
CASH AND CASH EQUIVALENTS, END OF YEAR	$	—		$	—		$	—		$	—		$	870		$	—		$	870

Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements - Narrative (Details) $ in Millions		12 Months Ended
	Jan. 04, 2016	Dec. 31, 2018 USD ($) Unit	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Significant Accounting Policies and Recent Accounting Pronouncements [Line Items]
Number of reporting units \| Unit		9
Accounting Standards Update 2014-09 [Member] \| Other [Member]
Significant Accounting Policies and Recent Accounting Pronouncements [Line Items]
Portion of Revenue		5.00%
Accounting Standards Update 2014-09 [Member] \| Broking [Member]
Significant Accounting Policies and Recent Accounting Pronouncements [Line Items]
Portion of Revenue		48.00%
Accounting Standards Update 2014-09 [Member] \| Consulting [Member]
Significant Accounting Policies and Recent Accounting Pronouncements [Line Items]
Portion of Revenue		34.00%
Accounting Standards Update 2014-09 [Member] \| Outsourced administration [Member]
Significant Accounting Policies and Recent Accounting Pronouncements [Line Items]
Portion of Revenue		12.00%
Accounting Standards Update 2014-09 [Member] \| Reimbursed Expenses [Member]
Significant Accounting Policies and Recent Accounting Pronouncements [Line Items]
Portion of Revenue		1.00%
Accounting Standards Update 2017-07 [Member]
Significant Accounting Policies and Recent Accounting Pronouncements [Line Items]
Reclassification For Presentation		$ 280	$ 222	$ 203
Buildings [Member]
Significant Accounting Policies and Recent Accounting Pronouncements [Line Items]
Useful life		50 years
Willis Limited [Member]
Significant Accounting Policies and Recent Accounting Pronouncements [Line Items]
Unencumbered and available funds required		$ 140
Unencumbered and available cash balance required		79
Common Stock [Member]
Significant Accounting Policies and Recent Accounting Pronouncements [Line Items]
Reverse stock split ratio	1 to 2.6490
Retained earnings [Member] \| Accounting Standards Update 2016-02 [Member]
Significant Accounting Policies and Recent Accounting Pronouncements [Line Items]
Additional operating lease liabilities at the transition date		1,200
Right-of-Use Asset		$ 1,000
Minimum [Member]
Significant Accounting Policies and Recent Accounting Pronouncements [Line Items]
Variable interest entity ownership percentage		50.00%
Equity ownership voting percentage		20.00%
Minimum [Member] \| Internally developed software [Member]
Significant Accounting Policies and Recent Accounting Pronouncements [Line Items]
Useful life		3 years
Minimum [Member] \| Furniture, equipment and software [Member]
Significant Accounting Policies and Recent Accounting Pronouncements [Line Items]
Useful life		3 years
Maximum [Member]
Significant Accounting Policies and Recent Accounting Pronouncements [Line Items]
Equity ownership voting percentage		50.00%
Maximum [Member] \| Internally developed software [Member]
Significant Accounting Policies and Recent Accounting Pronouncements [Line Items]
Useful life		10 years
Maximum [Member] \| Furniture, equipment and software [Member]
Significant Accounting Policies and Recent Accounting Pronouncements [Line Items]
Useful life		10 years

Basis of Presentation, Significant Accounting Policies and Recent Accounting Pronouncements - Finite-lived Intangible Assets (Details)	12 Months Ended
	Dec. 31, 2018
Product [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Expected life	17 years 6 months
Favorable agreements [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Expected life	7 years
Management contracts [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Expected life	18 years
Minimum [Member] \| Client relationships [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Expected life	5 years
Minimum [Member] \| Software [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Expected life	4 years
Minimum [Member] \| Trademark and trade name [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Expected life	14 years
Maximum [Member] \| Client relationships [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Expected life	20 years
Maximum [Member] \| Software [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Expected life	7 years
Maximum [Member] \| Trademark and trade name [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Expected life	25 years

Merger, Acquisitions and Divestitures - Narrative (Details) $ / shares in Units, $ in Millions			12 Months Ended
	Dec. 21, 2018 USD ($)	Jan. 04, 2016 USD ($) $ / shares	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Cash acquired			$ 13	$ 0	$ 476
Other intangible assets, net			3,318	3,882
Goodwill			$ 10,465	$ 10,519	$ 10,413
Towers Watson & Co. [Member]
Business Acquisition [Line Items]
Duration that entity has been in existence (more than)		100 years
Conversion of Towers Watson stock to Willis stock, conversion ratio		2.6490
Cash acquired		$ 476
Total consideration		$ 8,723
Towers Watson & Co. [Member] \| Ordinary shares, $0.000115 nominal value [Member]
Business Acquisition [Line Items]
Ordinary shares, nominal value (USD per share) \| $ / shares		$ 0.000115
Alston Gayler Acquisition [Member]
Business Acquisition [Line Items]
Total consideration	$ 67
Consideration paid in cash	35
Deferred consideration	32
Other intangible assets, net	36
Goodwill	$ 24

Merger, Acquisitions and Divestitures - Calculation of Aggregate Merger Consideration (Details) $ / shares in Units, $ in Millions		12 Months Ended
	Jan. 04, 2016 USD ($) $ / shares shares	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Value of equity awards assumed		$ 37
Towers Watson & Co. [Member]
Business Acquisition [Line Items]
Number of shares of Towers Watson common stock outstanding as of January 4, 2016 \| shares	69,000,000
Exchange ratio	2.6490
Fair value of 184 million Willis ordinary shares	$ 8,686
Value of equity awards assumed	37
Aggregate Merger consideration	$ 8,723
Towers Watson & Co. [Member] \| Willis Group Holdings [Member]
Business Acquisition [Line Items]
Number of Willis Group Holdings shares issued (prior to reverse stock split) \| shares	184,000,000
Willis Group Holdings price per share on January 4, 2016 \| $ / shares	$ 47.18

Merger, Acquisitions and Divestitures - Global Wealth Solutions Divestiture (Details) - Affiliated Entity [Member] $ in Millions	3 Months Ended
	Sep. 30, 2017 USD ($)
Global Wealth Solutions Transaction [Line Items]
Global Wealth Solutions Transaction, Amounts of Transaction	$ 50
Global Wealth Solutions Transaction, Related Party Loan Collateral	$ 3
Global Wealth Solutions Transaction, Rate	3.00%
Global Wealth Solutions Transaction, Loan Receivable Term	10 years

Merger, Acquisitions and Divestitures - All divestitures (Details) $ in Millions	6 Months Ended	12 Months Ended
	Dec. 31, 2017 Business	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Dispositions [Abstract]
Dispositions, Number of Businesses \| Business	5
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal		$ (9)	$ 13	$ 2
Dispositions, Revenues prior to Sales			54
Dispositions Operating Income prior to Sales			$ 13

Revenue - Schedule of Effect of ASC 606 on Financial Statements (Details) - USD ($)
$ / shares in Units, $ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2017

Sep. 30, 2017

Jun. 30, 2017

Mar. 31, 2017

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Jan. 01, 2018

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

$ 2,379

$ 2,246

$ 2,379

$ 2,246

$ 2,555

404

430

404

430

942

985

942

985

467

447

467

447

1,647

1,711

1,647

1,711

864

804

864

804

559

615

559

615

540

558

540

558

^[1]

1,201

1,104

1,201

1,104

2,372

$ 1,859

$ 1,990

$ 2,292

2,078

$ 1,852

$ 1,953

$ 2,319

8,513

8,202

$ 7,887

Salaries and benefits

5,123

4,967

4,849

INCOME FROM OPERATIONS BEFORE INCOME TAXES

208

203

178

Income from operations

470

259

(26)

401

809

516

348

851

492

342

Provision for income taxes

(136)

100

383

221

253

(54)

352

715

592

438

Diluted earnings per share

$ 378

$ 44

$ 58

$ 215

$ 245

$ (54)

$ 33

$ 344

$ 695

$ 568

$ 420

Basic earnings per share

$ 2.91

$ 0.34

$ 0.44

$ 1.62

$ 1.85

$ (0.40)

$ 0.24

$ 2.51

$ 5.29

$ 4.21

$ 3.07

$ 2.89

$ 0.33

$ 0.44

$ 1.61

$ 1.84

$ (0.40)

$ 0.24

$ 2.50

$ 5.27

$ 4.18

$ 3.04

$ 1,288

$ 862

$ 933

Calculated under revenue guidance in Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]

(54)

(75)

$ (85)

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

2,555

519

902

486

1,637

714

570

Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]

1,421

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

$ 2,198

$ 2,246

2,198

2,246

302

430

302

430

1,051

985

1,051

985

419

447

419

447

1,754

1,711

1,754

1,711

863

479

615

479

615

529

558

529

558

964

$ 1,104

964

$ 1,104

8,613

Salaries and benefits

5,098

INCOME FROM OPERATIONS BEFORE INCOME TAXES

235

Income from operations

907

949

Provision for income taxes

(154)

795

Diluted earnings per share

$ 775

Basic earnings per share

$ 5.90

$ 5.87

$ 1,338

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]

(104)

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

^[2]

181

309

^[3]

102

^[4]

(109)

(83)

^[4]

^[5]

(107)

(74)

^[6]

^[6]

^[7]

^[8]

$ 237

237

$ 317

^{[9],[10],[11],[12],[13]}

(100)

Salaries and benefits

^{[14],[15],[16]}

INCOME FROM OPERATIONS BEFORE INCOME TAXES

^{[14],[15],[16]}

(27)

Income from operations

(98)

(98)

Provision for income taxes

^[17]

(80)

Diluted earnings per share

$ (80)

Basic earnings per share

$ (0.61)

$ (0.60)

^[18]

$ (50)

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

^[18]

$ 50

[1]	Equity includes (a) Ordinary shares $0.000304635 nominal value; Authorized 1,510,003,775; Issued 128,921,530 (2018) and 132,139,581 (2017); Outstanding 128,921,530 (2018) and 132,139,581 (2017); (b) Ordinary shares, €1 nominal value; Authorized and Issued 40,000 shares in 2018 and 2017; and (c) Preference shares, $0.000115 nominal value; Authorized 1,000,000,000 and Issued none in 2018 and 2017.
[2]	Accounts receivable, net, now includes receivables that have been billed, not yet billed and short-term contract assets. This adjustment is the result of the cumulative adjustments to revenue that have not yet been collected from our customers, but are expected to be collected within the next twelve months. The most significant increases to this balance result from revenue acceleration under ASC 606 for Medicare and proportional treaty broking commissions.
[3]	Prepaid and other current assets include the impact of costs deferred in connection with our broking pre-placement activities. These costs are being deferred while the related pre-placement work is performed, and amortized as the related revenue is recognized, typically upon policy inception. Since the amortization period associated with these fulfillment costs is less than one year, these deferred costs have been classified as a current asset.
[4]	Prior to the adoption of ASC 606, costs that we deferred related to certain system implementation activities had been included in fixed assets, net. These costs, adjusted based on the guidance in ASC 606, have now been included in other non-current assets. Additionally we have included less significant impacts of adjustments to deferred tax assets and have classified non-current contract assets within non-current assets.
[5]	Deferred revenue has been adjusted primarily to reflect revenue acceleration in our Medicare broking business. Additional adjustments were included to accelerate the license component of certain software arrangements and to net deferred revenue with contract assets.
[6]	Other current liabilities, which include current taxes payable, and deferred tax liabilities, have been adjusted for the tax effects of the individual changes resulting from the adoption of ASC 606. The income tax expense was calculated based on the U.S. and foreign statutory rates applicable to adjustments made. Where applicable, a U.S. statutory rate of 21% was used.
[7]	Provision for liabilities has been adjusted for additional reserves for long-term post-placement obligations in our broking business.
[8]	Retained earnings has been adjusted for the net impact of the adoption of ASC 606. See the discussion of the significant pre-tax changes by revenue in the following section.
[9]	Health and benefits broking — Revenue for certain Health and Benefits broking arrangements, in our Human Capital and Benefits segment, will now be recognized evenly over the year to reflect the nature of the ongoing obligations to our customers as well as receipt of the monthly commissions. These contracts are monthly or annual in nature, and are considered complete as of the transition date. Therefore, no retained earnings adjustment is required. The total effect to revenue as a result of this accounting change for the year ended December 31, 2018 was a decrease of $57 million.
[10]	Medicare broking — The majority of revenue recognition for this offering, within our Individual Marketplace business, has moved from monthly ratable recognition over the policy period, to recognition upon placement of the policy. Consequently, the Company will now recognize approximately two-thirds of one calendar year of expected commissions during its fourth quarter of the preceding calendar year. The remainder of the revenue is recognized consistently with methods used prior to the adoption of ASC 606. Therefore, at the adoption date, we have reflected a $271 million pre-tax increase to retained earnings for the portion of the revenue that would otherwise have been recognized during our 2018 calendar year since our earnings process was largely completed during the fourth quarter of 2017. Additionally, we have reflected a $40 million pretax adjustment to increase retained earnings related to previously deferred contingent revenue from placements made prior to 2018 because the earnings process was complete under ASC 606. During the year ended December 31, 2018, the accounting for this revenue stream under ASC 606 represented a reduction of revenue from ASC 605, Revenue Recognition (‘ASC 605’) accounting methods of $38 million.
[11]	Other adjustments — Certain other revenue changes with individually less significant adjustments were made to retained earnings as of the adoption date totaling a net $28 million. The cumulative change to revenue for the year ended December 31, 2018 for other revenue streams not discussed above resulting from the ASC 606 adoption was a decrease of $7 million.
[12]	Proportional treaty reinsurance broking — The revenue recognition for proportional treaty reinsurance broking commissions, within our Investment, Risk and Reinsurance segment, has moved from recognition upon the receipt of the monthly or quarterly treaty statements from the ceding insurance carriers, to the recognition of an estimate of expected commissions upon the policy effective date. Since the majority of revenue recognized historically based on these monthly or quarterly statements was received over a two-year period, we reflected a $50 million pretax increase to retained earnings at the adoption date for the portion of revenue that would otherwise have been recognized during our 2018 calendar year related to policies effective in 2017 or prior years. For the year ended December 31, 2018, this accounting change resulted in a revenue increase of $2 million related to this adjustment.
[13]	Revenue was adjusted for the following significant changes:
[14]	Other cost adjustments — This guidance now applies to our broking arrangements and certain consulting engagements. While the costs deferred for our broking arrangements will typically be amortized within one year, costs now deferred related to certain consulting arrangements will be amortized over a longer term. We have increased pre-tax retained earnings by $75 million, primarily to reflect the total changes to contract costs as of the adoption date. For the year ended December 31, 2018, these changes resulted in a decrease in expense of $8 million.
[15]	Salaries and benefits and depreciation expense have been impacted by the guidance for deferred costs. Our accounting for these deferred costs has changed for certain revenue streams with system implementation activities, and other types of arrangements with associated costs, that now meet the criteria for cost deferral under ASC 606:
[16]	System implementation activities — For those portions of the business that previously deferred costs, the length of time over which we amortize those costs will extend to a longer estimated contract term. For 2017 and prior years, these costs were amortized over a typical period of 3-5 years in accordance with the initial stated terms of the customer agreements. Additionally, the composition of deferred costs has been adjusted to reflect the guidance in ASC 606. A reduction adjustment to retained earnings of $46 million was recorded on the adoption date to reflect these changes. Further, the amortization of the costs are no longer classified as depreciation expense, but rather included in salaries and benefits. These adjustments resulted in an increase in expense of $6 million for the year ended December 31, 2018.
[17]	The provision for income taxes for the year ended December 31, 2018 was $18 million lower than our provision on an ASC 605 basis. The income tax expense was calculated based on the U.S. and foreign statutory rates applicable to adjustments made. Where applicable, a U.S. statutory rate of 21% was used. There was a $101 million net tax reduction to retained earnings upon adoption of ASC 606.
[18]	As part of the changes in accounting for deferred costs, amounts capitalized relating to system implementation activities are now classified as operating cash flows. Prior to 2018, those costs capitalized under previous guidance were included in Capitalized software costs as an investing cash outflow.

Revenue - Narrative (Details) - USD ($)
$ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2017

Sep. 30, 2017

Jun. 30, 2017

Mar. 31, 2017

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Jan. 01, 2018

U.S. statutory tax rate

21.00%

35.00%

$ 2,372

$ 1,859

$ 1,990

$ 2,292

$ 2,078

$ 1,852

$ 1,953

$ 2,319

$ 8,513

$ 8,202

$ 7,887

^[1]

1,201

1,104

1,201

1,104

Operating Expenses

1,902

$ 1,842

$ 1,927

$ 2,033

$ 1,998

$ 1,878

$ 1,892

$ 1,918

7,704

7,686

7,539

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

(136)

$ 100

$ 96

January 1 2018 [Member]

Contract with Customer, Liability, Revenue Recognized

$ 389

Other [Member] | Accounting Standards Update 2014-09 [Member] | Maximum [Member]

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

Revenue, Percentage of Total Revenue

5.00%

System implementation activities [Member] | Accounting Standards Update 2014-09 [Member] | For 2017 and Prior Years [Member] | Minimum [Member]

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

Costs amortization period

3 years

System implementation activities [Member] | Accounting Standards Update 2014-09 [Member] | For 2017 and Prior Years [Member] | Maximum [Member]

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

Costs amortization period

5 years

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

^{[2],[3],[4],[5],[6]}

$ (100)

^[7]

$ 237

237

$ 317

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Medicare broking [Member] | Accounting Standards Update 2014-09 [Member]

^[8]

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

^[3]

(38)

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Proportional treaty reinsurance broking [Member] | Accounting Standards Update 2014-09 [Member]

^[3]

311

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

^[5]

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Health and benefits broking [Member] | Accounting Standards Update 2014-09 [Member]

^[5]

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

^[2]

(57)

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Other [Member] | Accounting Standards Update 2014-09 [Member]

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

^[4]

(7)

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | System implementation activities [Member] | Accounting Standards Update 2014-09 [Member]

^[4]

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Other Cost Adjustments [Member] | Accounting Standards Update 2014-09 [Member]

^[9]

(46)

Operating Expenses

^[9]

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Income Tax Effect [Member] | Accounting Standards Update 2014-09 [Member]

^[10]

Operating Expenses

^[10]

(8)

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

^[8]

(101)

Current Year Policies [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Medicare broking [Member] | Accounting Standards Update 2014-09 [Member]

^[8]

$ (18)

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

Prior Policy Years [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Medicare broking [Member] | Accounting Standards Update 2014-09 [Member]

271

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

$ 40

[1]	Equity includes (a) Ordinary shares $0.000304635 nominal value; Authorized 1,510,003,775; Issued 128,921,530 (2018) and 132,139,581 (2017); Outstanding 128,921,530 (2018) and 132,139,581 (2017); (b) Ordinary shares, €1 nominal value; Authorized and Issued 40,000 shares in 2018 and 2017; and (c) Preference shares, $0.000115 nominal value; Authorized 1,000,000,000 and Issued none in 2018 and 2017.
[2]	Health and benefits broking — Revenue for certain Health and Benefits broking arrangements, in our Human Capital and Benefits segment, will now be recognized evenly over the year to reflect the nature of the ongoing obligations to our customers as well as receipt of the monthly commissions. These contracts are monthly or annual in nature, and are considered complete as of the transition date. Therefore, no retained earnings adjustment is required. The total effect to revenue as a result of this accounting change for the year ended December 31, 2018 was a decrease of $57 million.
[3]	Medicare broking — The majority of revenue recognition for this offering, within our Individual Marketplace business, has moved from monthly ratable recognition over the policy period, to recognition upon placement of the policy. Consequently, the Company will now recognize approximately two-thirds of one calendar year of expected commissions during its fourth quarter of the preceding calendar year. The remainder of the revenue is recognized consistently with methods used prior to the adoption of ASC 606. Therefore, at the adoption date, we have reflected a $271 million pre-tax increase to retained earnings for the portion of the revenue that would otherwise have been recognized during our 2018 calendar year since our earnings process was largely completed during the fourth quarter of 2017. Additionally, we have reflected a $40 million pretax adjustment to increase retained earnings related to previously deferred contingent revenue from placements made prior to 2018 because the earnings process was complete under ASC 606. During the year ended December 31, 2018, the accounting for this revenue stream under ASC 606 represented a reduction of revenue from ASC 605, Revenue Recognition (‘ASC 605’) accounting methods of $38 million.
[4]	Other adjustments — Certain other revenue changes with individually less significant adjustments were made to retained earnings as of the adoption date totaling a net $28 million. The cumulative change to revenue for the year ended December 31, 2018 for other revenue streams not discussed above resulting from the ASC 606 adoption was a decrease of $7 million.
[5]	Proportional treaty reinsurance broking — The revenue recognition for proportional treaty reinsurance broking commissions, within our Investment, Risk and Reinsurance segment, has moved from recognition upon the receipt of the monthly or quarterly treaty statements from the ceding insurance carriers, to the recognition of an estimate of expected commissions upon the policy effective date. Since the majority of revenue recognized historically based on these monthly or quarterly statements was received over a two-year period, we reflected a $50 million pretax increase to retained earnings at the adoption date for the portion of revenue that would otherwise have been recognized during our 2018 calendar year related to policies effective in 2017 or prior years. For the year ended December 31, 2018, this accounting change resulted in a revenue increase of $2 million related to this adjustment.
[6]	Revenue was adjusted for the following significant changes:
[7]	Retained earnings has been adjusted for the net impact of the adoption of ASC 606. See the discussion of the significant pre-tax changes by revenue in the following section.
[8]	The provision for income taxes for the year ended December 31, 2018 was $18 million lower than our provision on an ASC 605 basis. The income tax expense was calculated based on the U.S. and foreign statutory rates applicable to adjustments made. Where applicable, a U.S. statutory rate of 21% was used. There was a $101 million net tax reduction to retained earnings upon adoption of ASC 606.
[9]	System implementation activities — For those portions of the business that previously deferred costs, the length of time over which we amortize those costs will extend to a longer estimated contract term. For 2017 and prior years, these costs were amortized over a typical period of 3-5 years in accordance with the initial stated terms of the customer agreements. Additionally, the composition of deferred costs has been adjusted to reflect the guidance in ASC 606. A reduction adjustment to retained earnings of $46 million was recorded on the adoption date to reflect these changes. Further, the amortization of the costs are no longer classified as depreciation expense, but rather included in salaries and benefits. These adjustments resulted in an increase in expense of $6 million for the year ended December 31, 2018.
[10]	Other cost adjustments — This guidance now applies to our broking arrangements and certain consulting engagements. While the costs deferred for our broking arrangements will typically be amortized within one year, costs now deferred related to certain consulting arrangements will be amortized over a longer term. We have increased pre-tax retained earnings by $75 million, primarily to reflect the total changes to contract costs as of the adoption date. For the year ended December 31, 2018, these changes resulted in a decrease in expense of $8 million.

Revenue - Schedule of Effect of ASC 606 on Items in Retained Earnings and Earnings (Details) - USD ($)
$ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2017

Sep. 30, 2017

Jun. 30, 2017

Mar. 31, 2017

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Jan. 01, 2018

^[1]

$ 1,201

$ 1,104

$ 1,201

$ 1,104

(136)

100

$ 96

2,372

$ 1,859

$ 1,990

$ 2,292

2,078

$ 1,852

$ 1,953

$ 2,319

8,513

8,202

7,887

1,902

1,842

1,927

2,033

1,998

1,878

1,892

1,918

7,704

7,686

7,539

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]

378

$ 44

$ 58

$ 215

$ 245

$ (54)

$ 33

$ 344

695

$ 568

$ 420

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

^[2]

$ 237

237

$ 317

^[3]

^{[4],[5],[6],[7],[8]}

(100)

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member] | Medicare broking [Member]

(80)

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

^[5]

311

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member] | Proportional treaty reinsurance broking [Member]

^[5]

(38)

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

^[7]

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member] | Health and benefits broking [Member]

^[7]

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member] | Other [Member]

^[4]

(57)

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

^[6]

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member] | Total Revenue Adjustments [Member]

^[6]

(7)

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

389

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member] | System implementation activities [Member]

(100)

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

^[9]

(46)

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member] | Other Cost Adjustments [Member]

^[9]

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

^[10]

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member] | Total Cost Adjustments [Member]

^[10]

(8)

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member] | Income Tax Effect [Member]

(2)

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

^[3]

$ (101)

^[3]

$ (18)

[1]	Equity includes (a) Ordinary shares $0.000304635 nominal value; Authorized 1,510,003,775; Issued 128,921,530 (2018) and 132,139,581 (2017); Outstanding 128,921,530 (2018) and 132,139,581 (2017); (b) Ordinary shares, €1 nominal value; Authorized and Issued 40,000 shares in 2018 and 2017; and (c) Preference shares, $0.000115 nominal value; Authorized 1,000,000,000 and Issued none in 2018 and 2017.
[2]	Retained earnings has been adjusted for the net impact of the adoption of ASC 606. See the discussion of the significant pre-tax changes by revenue in the following section.
[3]	The provision for income taxes for the year ended December 31, 2018 was $18 million lower than our provision on an ASC 605 basis. The income tax expense was calculated based on the U.S. and foreign statutory rates applicable to adjustments made. Where applicable, a U.S. statutory rate of 21% was used. There was a $101 million net tax reduction to retained earnings upon adoption of ASC 606.
[4]	Health and benefits broking — Revenue for certain Health and Benefits broking arrangements, in our Human Capital and Benefits segment, will now be recognized evenly over the year to reflect the nature of the ongoing obligations to our customers as well as receipt of the monthly commissions. These contracts are monthly or annual in nature, and are considered complete as of the transition date. Therefore, no retained earnings adjustment is required. The total effect to revenue as a result of this accounting change for the year ended December 31, 2018 was a decrease of $57 million.
[5]	Medicare broking — The majority of revenue recognition for this offering, within our Individual Marketplace business, has moved from monthly ratable recognition over the policy period, to recognition upon placement of the policy. Consequently, the Company will now recognize approximately two-thirds of one calendar year of expected commissions during its fourth quarter of the preceding calendar year. The remainder of the revenue is recognized consistently with methods used prior to the adoption of ASC 606. Therefore, at the adoption date, we have reflected a $271 million pre-tax increase to retained earnings for the portion of the revenue that would otherwise have been recognized during our 2018 calendar year since our earnings process was largely completed during the fourth quarter of 2017. Additionally, we have reflected a $40 million pretax adjustment to increase retained earnings related to previously deferred contingent revenue from placements made prior to 2018 because the earnings process was complete under ASC 606. During the year ended December 31, 2018, the accounting for this revenue stream under ASC 606 represented a reduction of revenue from ASC 605, Revenue Recognition (‘ASC 605’) accounting methods of $38 million.
[6]	Other adjustments — Certain other revenue changes with individually less significant adjustments were made to retained earnings as of the adoption date totaling a net $28 million. The cumulative change to revenue for the year ended December 31, 2018 for other revenue streams not discussed above resulting from the ASC 606 adoption was a decrease of $7 million.
[7]	Proportional treaty reinsurance broking — The revenue recognition for proportional treaty reinsurance broking commissions, within our Investment, Risk and Reinsurance segment, has moved from recognition upon the receipt of the monthly or quarterly treaty statements from the ceding insurance carriers, to the recognition of an estimate of expected commissions upon the policy effective date. Since the majority of revenue recognized historically based on these monthly or quarterly statements was received over a two-year period, we reflected a $50 million pretax increase to retained earnings at the adoption date for the portion of revenue that would otherwise have been recognized during our 2018 calendar year related to policies effective in 2017 or prior years. For the year ended December 31, 2018, this accounting change resulted in a revenue increase of $2 million related to this adjustment.
[8]	Revenue was adjusted for the following significant changes:
[9]	System implementation activities — For those portions of the business that previously deferred costs, the length of time over which we amortize those costs will extend to a longer estimated contract term. For 2017 and prior years, these costs were amortized over a typical period of 3-5 years in accordance with the initial stated terms of the customer agreements. Additionally, the composition of deferred costs has been adjusted to reflect the guidance in ASC 606. A reduction adjustment to retained earnings of $46 million was recorded on the adoption date to reflect these changes. Further, the amortization of the costs are no longer classified as depreciation expense, but rather included in salaries and benefits. These adjustments resulted in an increase in expense of $6 million for the year ended December 31, 2018.
[10]	Other cost adjustments — This guidance now applies to our broking arrangements and certain consulting engagements. While the costs deferred for our broking arrangements will typically be amortized within one year, costs now deferred related to certain consulting arrangements will be amortized over a longer term. We have increased pre-tax retained earnings by $75 million, primarily to reflect the total changes to contract costs as of the adoption date. For the year ended December 31, 2018, these changes resulted in a decrease in expense of $8 million.

Revenue - Schedule of Contract Balances (Details) - USD ($) $ in Millions	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements And Changes In Accounting Principles [Abstract]
Billed Receivable, Current	$ 1,702	$ 1,933
Unbilled Receivable, Current	356	276
Contract asset, Current	321	346
Accounts receivable, net	2,379	2,555	$ 2,246
Non-current accounts receivable, net	20	33	$ 33
Contract asset, Noncurrent	3	5
Deferred revenue	448	463
Allowance for doubtful debts	$ 40	$ 45

Revenue - Schedule of Changes in Allowance for Doubtful Accounts (Details) - Allowance for doubtful accounts [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	$ 45	$ 40	$ 22
Additions charged to costs and expenses	9	17	36
Charges to other accounts - acquisitions			8
Deductions/other movements	(15)	(9)	(27)
Foreign exchange	1	(3)	1
Balance at end of year	$ 40	$ 45	$ 40

Revenue - Schedule of Remaining Performance Obligations (Details 1) $ in Millions	Dec. 31, 2018 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue, Remaining Performance Obligation	$ 1,264
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue, Remaining Performance Obligation	$ 441
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue, Remaining Performance Obligation	$ 357
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue, Remaining Performance Obligation	$ 466
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period

Revenue - Schedule of Capitalized and Deferred Costs (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
New Accounting Pronouncements And Changes In Accounting Principles [Abstract]
Capitalized Contract Cost, Net	$ 126
Capitalized Contract Cost, Additions	465
Capitalized Contract Cost, Amortization	(442)
Capitalized Contract Cost, Impairment Loss	0
Capitalized Contract Cost, Foreign Exchange Translation Gain (Loss)	(1)
Capitalized Contract Cost, Net	$ 148

Segment Information - Revenue (Net of Reimbursable Expenses) of the Reported Segments (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Revenue	$ 2,372	$ 1,859	$ 1,990	$ 2,292	$ 2,078	$ 1,852	$ 1,953	$ 2,319	$ 8,513	$ 8,202	$ 7,887
Income from operations	$ 470	$ 17	$ 63	$ 259	$ 80	$ (26)	$ 61	$ 401	809	516	348
HCB [Member]
Segment Reporting Information [Line Items]
Revenue									3,295
CRB [Member]
Segment Reporting Information [Line Items]
Revenue									2,852
IRR [Member]
Segment Reporting Information [Line Items]
Revenue									1,564
BDA [Member]
Segment Reporting Information [Line Items]
Revenue									765
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue									8,399	8,093	7,841
Income from operations									1,845	1,739	1,646
Operating Segments [Member] \| HCB [Member]
Segment Reporting Information [Line Items]
Revenue									3,233	3,176	3,100
Income from operations									789	774	722
Operating Segments [Member] \| CRB [Member]
Segment Reporting Information [Line Items]
Revenue									2,852	2,709	2,608
Income from operations									528	483	458
Operating Segments [Member] \| IRR [Member]
Segment Reporting Information [Line Items]
Revenue									1,556	1,474	1,473
Income from operations									384	329	346
Operating Segments [Member] \| BDA [Member]
Segment Reporting Information [Line Items]
Revenue									758	734	660
Income from operations									$ 144	$ 153	$ 120

Segment Information - Reconciliation of Information Reported by Segment to Consolidated Amounts (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue:
Revenue	$ 2,372	$ 1,859	$ 1,990	$ 2,292	$ 2,078	$ 1,852	$ 1,953	$ 2,319	$ 8,513	$ 8,202	$ 7,887
Income from operations	$ 470	$ 17	$ 63	$ 259	$ 80	$ (26)	$ 61	$ 401	809	516	348
Amortization									(534)	(581)	(591)
Restructuring costs									0	(132)	(193)
Interest expense									(208)	(188)	(184)
Other income, net									250	164	178
INCOME FROM OPERATIONS BEFORE INCOME TAXES									851	492	342
Operating Segments [Member]
Revenue:
Revenue									8,399	8,093	7,841
Income from operations									1,845	1,739	1,646
Segment Reconciling Items [Member]
Revenue:
Revenue									114	109	104
Fair value adjustment to deferred revenue											(58)
Amortization									(534)	(581)	(591)
Restructuring costs										(132)	(193)
Transaction and integration expenses									(202)	(269)	(177)
Provisions for significant litigation										(11)	(50)
Unallocated, net									(300)	(230)	(229)
Interest expense									(208)	(188)	(184)
Other income, net									$ 250	$ 164	$ 178

Segment Information - Revenue and Long-Lived Assets by Geographical Areas (Details) - USD ($)
$ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2017

Sep. 30, 2017

Jun. 30, 2017

Mar. 31, 2017

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

$ 2,372

$ 1,859

$ 1,990

$ 2,292

$ 2,078

$ 1,852

$ 1,953

$ 2,319

$ 8,513

$ 8,202

$ 7,887

^[1]

15,906

16,551

15,906

16,551

16,411

Ireland [Member]

138

107

^[1]

127

114

United States [Member]

3,970

3,821

3,395

^[1]

11,068

9,988

11,068

9,988

11,400

United Kingdom [Member]

1,926

1,815

2,236

^[1]

2,349

3,173

2,349

3,173

2,431

Rest of World [Member]

2,479

2,459

2,164

Total Foreign Countries [Member]

^[1]

2,411

3,263

2,411

3,263

2,466

8,375

8,095

7,795

^[1]

$ 15,828

$ 16,424

$ 15,828

$ 16,424

$ 16,297

[1]	Long-lived assets do not include deferred tax assets.

Restructuring Costs - Narrative (Details) $ in Millions	12 Months Ended					45 Months Ended
Restructuring Costs - Narrative (Details) $ in Millions	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2017 USD ($) Position
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 0	$ 132	$ 193
Operational Improvement Program [Member]
Restructuring Cost and Reserve [Line Items]
Number of support roles moved from higher cost locations to lower cost locations (more than) \| Position						3,500
Restructuring costs		134	145	$ 126	$ 36
Cumulative Restructuring Cost						$ 441
Business Restructure Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs		$ (2)	$ 48

Restructuring Costs - Restructuring Liability (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Dec. 31, 2014

Termination benefits [Member]

$ 0

$ 132

$ 193

Professional services and other [Member]

Operational Improvement Program [Member]

^[1]

125

$ 11

$ 0

134

145

126

(18)

(138)

(146)

(111)

(25)

Operational Improvement Program [Member] | Termination benefits [Member]

(12)

(41)

(31)

(26)

(11)

Operational Improvement Program [Member] | Professional services and other [Member]

^[2]

122

(6)

(97)

(115)

(85)

(14)

Business Restructure Program [Member]

$ 6

(2)

(1)

(23)

(22)

Business Restructure Program [Member] | Termination benefits [Member]

(2)

(1)

(23)

(19)

Business Restructure Program [Member] | Professional services and other [Member]

^[2]

(3)

Movement in Property, Plant and Equipment [Roll Forward]

$ 0

[1]	Other includes salary and benefits, premises, and other expenses incurred to support the ongoing management and facilitation of the programs
[2]	Other includes salary and benefits, premises, and other expenses incurred to support the ongoing management and facilitation of the program

Income Taxes - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
Income Taxes - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
U.S. statutory tax rate	21.00%	35.00%	35.00%
Tax Cuts And Jobs Act Of 2017 Incomplete Accounting Change In Tax Rate Deferred Tax Liability		$ (208)
Tax Cuts And Jobs Act Of 2017 Incomplete Accounting Change In Tax Rate Provisional Deferred Income Tax Benefit		208
Tax Cuts And Jobs Act Of 2017 Complete Accounting Change In Tax Rate Provisional Additional Deferred Income Tax Benefit	$ 8
Tax Cuts and Jobs Act, Complete Accounting, Additional increase to income tax expense	$ 8
Percentage of impact on effective tax rate	1.00%
Tax Cuts and Jobs Act, Incomplete Accounting, Repatriation of Foreign Earnings, Provisional Income Tax Expense (Benefit)		1
Tax Cuts And Jobs Act Of 2017 Incomplete Accounting Provisional Transition Tax For Foreign Earnings Provisional Income Tax Expense Benefit		(76)
Percentage of Dividends received from owned foreign corporations by US corporate shareholders	100.00%
Tax Cuts and Jobs Act, Incomplete Accounting, Bonus Depreciation, Provisional Income Tax Expense (Benefit)		40
Tax Cuts and Jobs Act, Complete Accounting, Bonus Depreciation, Provisional Income Tax Expense (Benefit)	$ 8
Tax Cuts and Jobs Act, Incomplete Accounting, Bonus Depreciation, Provisional increase in net deferred tax liabilities		14
Tax Cuts and Jobs Act, Incomplete Accounting, Bonus Depreciation, Provisional Increase in Federal Current Income Taxes Receivable		14
Tax cuts and jobs act complete accounting, executive compensation, deduction limit	1
Tax cuts and jobs act incomplete accounting, executive compensation, provisional income tax expense (benefit)		8
Tax cuts and jobs act complete accounting, executive compensation, income tax expense (benefit)	$ 8
Tax cuts and jobs act complete accounting, executive compensation, measurement period adjustment in effective tax rate	1.00%
Estimated tax impact of GILTI	$ 15	0	$ 0
U.S. state and local tax expense	(12)	6	(5)
Deferred income tax benefit	(115)	(285)	(244)
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount		(204)	0
Tax Cuts and Jobs Act of 2017 Incomplete Accounting Change in Federal Corporate Tax Rate and Remeasurement of Deferred Tax Liabilities Related to Acquisition Based Intangibles Provisional Income Tax Benefit		(208)
Net operating losses	91	145
Deferred Tax Assets, Net of Valuation Allowance	607	592
Changes in valuation allowances	80	(13)	74
Decrease in valuation allowance	81
Valuation allowance	81	162
Additional repatriation, amount previously deemed indefinitely reinvested	2,100
Foreign withholding taxes and state income taxes	11
Cumulative earnings	7,200
Unrecognized tax benefits	49	59	56	$ 22
Decrease in unrecognized tax benefits is reasonably possible	2	3	$ 4
Interest on income taxes accrued	3	5
Income Tax Examination, Penalties Accrued		2
Internal Restructuring
Operating Loss Carryforwards [Line Items]
Decrease in valuation allowance	80
Tax Cuts and Jobs Act [Member]
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount		(204)
Foreign withholding taxes and state income taxes on potential repatriation, amount previously deemed indefinitely reinvested		1
Tax Cuts and Jobs Act [Member] \| One-Time Transition Tax [Member]
Operating Loss Carryforwards [Line Items]
Deferred tax expense (benefit) on potential repatriation, amount previously deemed indefinitely reinvested		(76)
Tax Cuts and Jobs Act [Member] \| One-Time Transition Tax [Member] \| Section 162(m) [Member]
Operating Loss Carryforwards [Line Items]
Federal and state tax expense (benefit) on potential repatriation, amount previously deemed indefinitely reinvested		72
Tax Cuts and Jobs Act [Member] \| Executive Compensation [Member] \| Section 162(m) [Member]
Operating Loss Carryforwards [Line Items]
Other Tax Expense (Benefit)		8
Valuation Allowance of Deferred Tax Assets [Member]
Operating Loss Carryforwards [Line Items]
U.S. state and local tax expense	(25)
Deferred income tax benefit	(71)
State and Local [Member]
Operating Loss Carryforwards [Line Items]
Tax Cuts and Jobs Act, Incomplete Accounting, One Time Transition Tax Liability For Foreign Subsidiaries, Provisional Income Tax Expense		2
Changes in valuation allowances		28
State and Local [Member] \| United States [Member] \| Tax Year 2019 Through 2038 [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, subject to expiration	515
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, valuation allowance	27	80
U.S. Federal and Non-U.S. [Member]
Operating Loss Carryforwards [Line Items]
Net operating losses	288
Operating loss carryforwards, not subject to expiration	239
U.S. Federal and Non-U.S. [Member] \| United States [Member] \| Tax Year 2019 Through 2038 [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, subject to expiration	49
Foreign Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, valuation allowance	20	34
Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Tax Cuts and Jobs Act, Incomplete Accounting, One Time Transition Tax Liability For Foreign Subsidiaries, Provisional Income Tax Expense		70
Tax Cuts and Jobs Act, Complete Accounting, Change In Tax Rate One Time Transition Tax Liability, Provisional Income Tax Benefit	$ 64
Revenue Commissioners, Ireland [Member] \| Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Foreign statutory income tax rate	25.00%
Her Majesty's Revenue and Customs (HMRC) [Member] \| Foreign Tax Authority [Member] \| Capital Loss Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, valuation allowance	$ 30	28
Minimum [Member]
Operating Loss Carryforwards [Line Items]
Significant change in unrecognized tax benefits is reasonably possible, amount of unrecorded benefit	$ 1
Maximum [Member]
Operating Loss Carryforwards [Line Items]
GILTI deduction rate	50.00%
Tax Cuts and Jobs Act, Incomplete Accounting, Repatriation of Foreign Earnings, Previously Deemed Indefinitely Reinvested		$ 219
Significant change in unrecognized tax benefits is reasonably possible, amount of unrecorded benefit	$ 3
Maximum [Member] \| Tax Cuts and Jobs Act [Member]
Operating Loss Carryforwards [Line Items]
Potential repatriation, amount previously deemed indefinitely reinvested	$ 219

Income Taxes - Income (Loss) from Operations Before Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income from Continuing Operations before Income Taxes and Interest in Earnings of Associates [Line Items]
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	$ 851	$ 492	$ 342
Revenue Commissioners, Ireland [Member] \| Domestic Tax Authority [Member]
Income from Continuing Operations before Income Taxes and Interest in Earnings of Associates [Line Items]
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(16)	(23)	(27)
Internal Revenue Service (IRS) [Member] \| Foreign Tax Authority [Member]
Income from Continuing Operations before Income Taxes and Interest in Earnings of Associates [Line Items]
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	(101)	(198)	(311)
Her Majesty's Revenue and Customs (HMRC) [Member] \| Foreign Tax Authority [Member]
Income from Continuing Operations before Income Taxes and Interest in Earnings of Associates [Line Items]
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	182	31	123
Other jurisdictions [Member] \| Foreign Tax Authority [Member]
Income from Continuing Operations before Income Taxes and Interest in Earnings of Associates [Line Items]
INCOME FROM OPERATIONS BEFORE INCOME TAXES AND INTEREST IN EARNINGS OF ASSOCIATES	$ 786	$ 682	$ 557

Income Taxes - (Provision for) Benefit from Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current tax expense:
U.S. federal taxes	$ (98)	$ (65)	$ (35)
U.S. state and local taxes	(25)	(7)	(14)
U.K. corporation tax	(16)	(14)	(28)
Other jurisdictions	(112)	(99)	(71)
Total current tax expense	(251)	(185)	(148)
Deferred tax benefit:
U.S. federal taxes	79	268	214
U.S. state and local taxes	12	(6)	5
U.K. corporation tax	(6)	9	(10)
Other jurisdictions	30	14	35
Total deferred tax benefit	115	285	244
Total (provision for)/benefit from income taxes	$ (136)	$ 100	$ 96

Income Taxes - Effective Tax Rate Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
INCOME FROM OPERATIONS BEFORE INCOME TAXES	$ 851	$ 492	$ 342
U.S. federal statutory income tax rate	21.00%	35.00%	35.00%
Income tax expense at U.S. federal tax rate	$ (179)	$ (172)	$ (120)
Non-deductible expenses and dividends	(44)	(68)	(15)
Non-deductible acquisition costs	(2)	(11)	(1)
Disposal of non-deductible goodwill	1	(11)	(2)
Impact of change in rate on deferred tax balances	7	0	15
Effect of foreign exchange and other differences	1	(3)	(6)
Non-deductible Venezuelan foreign exchange loss		(2)	(4)
Changes in valuation allowances	80	(13)	74
Net tax effect of intra-group items	99	97	98
Tax differentials of non-U.S. jurisdictions	(2)	69	80
Tax differentials of U.S. state taxes and local taxes	(77)	6	(14)
Global Intangible Low-Taxed Income (GILTI)	(15)	0	0
Impact of U.S. Tax Reform		204	0
Other items, net	(5)	4	(9)
Total (provision for)/benefit from income taxes	$ (136)	$ 100	$ 96

Income Taxes - Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Accrued expenses not currently deductible	$ 177	$ 131
Net operating losses	91	145
Capital loss carryforwards	30	28
Accrued retirement benefits	285	339
Deferred compensation	82	69
Stock options	22	24
Financial derivative transactions	1	18
Gross deferred tax assets	688	754
Less: valuation allowance	(81)	(162)
Net deferred tax assets	607	592
Deferred tax liabilities:
Cost of intangible assets, net of related amortization	825	929
Cost of tangible assets, net of related depreciation	37	56
Prepaid retirement benefits	101	114
Accrued revenue not currently taxable	144	62
Deferred tax liabilities	1,107	1,161
Net deferred tax liabilities	$ 500	$ 569

Income Taxes - Deferred Tax Liabilities, Balance Sheet Classification (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Other non-current assets	$ 59	$ 46
Deferred tax liabilities	559	615
Net deferred tax liabilities	$ 500	$ 569

Income Taxes - Valuation Allowance (Details) - Valuation Allowance of Deferred Tax Assets [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	$ 162	$ 134	$ 187
Additions charged to costs and expenses	18	35	0
Charges to other accounts - acquisitions		0	21
Deductions	(99)	(7)	(74)
Balance at end of year	$ 81	$ 162	$ 134

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	$ 59	$ 56	$ 22
Increases related to acquisitions		0	33
Increases related to tax positions in prior years	2	2	1
Decreases related to tax positions in prior years	(4)	(5)	(9)
Decreases related to settlements	(4)	0	(1)
Decreases related to lapse in statute of limitations	(5)	(2)	(1)
Increases related to current year tax positions	3	9	11
Cumulative translation adjustment and other adjustments	(2)	(1)	0
Balance at end of year	$ 49	$ 59	$ 56

Income Taxes - Summary of Tax Years that Remain Open to Tax Examination in Major Tax Jurisdictions (Details)	12 Months Ended
	Dec. 31, 2018
U.S. - Federal [Member]
Income Tax Contingency [Line Items]
Open Tax Years	2015 and forward
State and Local [Member]
Income Tax Contingency [Line Items]
Open Tax Years	2013 and forward
Foreign Tax Authority [Member] \| United Kingdom [Member]
Income Tax Contingency [Line Items]
Open Tax Years	2010 and forward
Foreign Tax Authority [Member] \| Ireland [Member]
Income Tax Contingency [Line Items]
Open Tax Years	2014 and forward
Foreign Tax Authority [Member] \| France [Member]
Income Tax Contingency [Line Items]
Open Tax Years	2010 and forward
Foreign Tax Authority [Member] \| Germany [Member]
Income Tax Contingency [Line Items]
Open Tax Years	2010 and forward
Foreign Tax Authority [Member] \| Canada - Federal [Member]
Income Tax Contingency [Line Items]
Open Tax Years	2011 and forward

Fixed Assets - Components of Fixed Assets (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

$ 1,862

$ 1,481

Additions

319

394

(313)

(82)

^[1]

(102)

(56)

Movement in Accumulated Depreciation, Depletion and Amortization, Property, Plant and Equipment [Roll Forward]

1,710

1,862

$ 1,481

(877)

(642)

(213)

^[2]

(252)

^[2]

(178)

277

^[1]

(34)

(768)

(877)

(642)

Transaction and integration expenses

942

985

202

269

177

Transaction and integration expenses

Movement in Accumulated Depreciation, Depletion and Amortization, Property, Plant and Equipment [Roll Forward]

Transaction and integration expenses

Furniture, equipment and software [Member]

Movement in Property, Plant and Equipment [Roll Forward]

1,300

1,009

Additions

249

303

(278)

(61)

^[1]

(102)

(39)

Movement in Accumulated Depreciation, Depletion and Amortization, Property, Plant and Equipment [Roll Forward]

1,130

1,300

1,009

(652)

(464)

^[2]

(155)

(199)

250

^[1]

(26)

(519)

(652)

(464)

Leasehold Improvements [Member]

611

648

Movement in Property, Plant and Equipment [Roll Forward]

468

382

Additions

(35)

(21)

(15)

Movement in Accumulated Depreciation, Depletion and Amortization, Property, Plant and Equipment [Roll Forward]

488

468

382

(176)

(137)

^[2]

(54)

(47)

(6)

(197)

(176)

(137)

Land and Building [Member]

291

292

Movement in Property, Plant and Equipment [Roll Forward]

(2)

Movement in Accumulated Depreciation, Depletion and Amortization, Property, Plant and Equipment [Roll Forward]

(49)

(41)

^[2]

(4)

(6)

(2)

(52)

(49)

$ (41)

$ 40

$ 45

[1]	Pertains to costs related to certain system implementation activities that have now been included in other non-current assets based on the guidance in ASC 606. See Note 4 — Revenue for further information.
[2]	Depreciation expense included here does not equal the depreciation expense on the statements of comprehensive income for the years ended December 31, 2018 and 2017 due to the inclusion of $5 million and $49 million, respectively, which have been classified as transaction and integration expenses.

Fixed Assets - Assets Held Under Capital Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property,Plant and Equipment [LineItems]
Capital leases	$ 31	$ 31
Accumulated depreciation	(16)	(14)
Net book value	15	17
Capital Leases [Member]
Property,Plant and Equipment [LineItems]
Depreciation	$ 2	$ 2	$ 2

Goodwill and Other Intangible Assets - Components of Goodwill (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2018

Dec. 31, 2017

$ 11,011

$ 10,905

(492)

10,519

10,413

(5)

(63)

(87)

161

10,957

11,011

(492)

10,465

10,519

HCB [Member]

4,342

4,412

(130)

4,212

4,282

(113)

(31)

(42)

4,300

4,342

(130)

4,170

4,212

CRB [Member]

2,261

2,178

(362)

1,899

1,816

^[1]

(5)

(34)

2,308

2,261

(362)

1,946

1,899

IRR [Member]

1,851

1,758

1,851

1,758

(72)

^[1]

100

(5)

(27)

(11)

1,792

1,851

1,792

1,851

BDA [Member]

2,557

2,557

2,557

$ 2,557

[1]	Represents the reallocation of goodwill related to certain businesses which were realigned among the segments as of January 1, 2018. See Note 5 — Segment Information for further information.

Goodwill and Other Intangible Assets - Finite-Lived Intangible Assets and Liabilities (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2018

Dec. 31, 2017

Jan. 04, 2016

$ 3,882

$ 4,332

(7)

(45)

(536)

(583)

^[1]

(60)

128

Finite-lived intangible assets, gross carrying amount

3,318

3,882

5,318

5,408

Finite-lived intangible assets, accumulated amortization

(2,000)

(1,526)

Finite-lived intangible liabilities, gross carrying amount

Finite-lived intangible liabilities, accumulated amortization

(13)

(8)

In Process Research and Development [Member]

Indefinite-Lived Intangible Assets (Excluding Goodwill)

$ 39

Client relationships [Member]

2,342

2,655

(7)

(44)

(341)

(379)

^[1]

(47)

Finite-lived intangible assets, gross carrying amount

1,986

2,342

3,401

3,462

Finite-lived intangible assets, accumulated amortization

(1,415)

(1,120)

Management contracts [Member]

(4)

^[1]

(4)

Finite-lived intangible assets, gross carrying amount

Finite-lived intangible assets, accumulated amortization

(15)

(12)

Software [Member]

^[2]

473

570

^[2]

^[2]

(140)

(150)

^[1],[2]

(5)

^[2]

Finite-lived intangible assets, gross carrying amount

328

473

^[2]

749

764

Finite-lived intangible assets, accumulated amortization

(421)

(291)

Trademark and trade name [Member]

966

1,006

(1)

(44)

^[1]

(2)

Finite-lived intangible assets, gross carrying amount

920

966

1,052

1,055

Finite-lived intangible assets, accumulated amortization

(132)

(89)

Product [Member]

(4)

(3)

^[1]

(2)

Finite-lived intangible assets, gross carrying amount

Finite-lived intangible assets, accumulated amortization

(9)

(6)

Favorable agreements [Member]

(2)

^[1]

Finite-lived intangible assets, gross carrying amount

Finite-lived intangible assets, accumulated amortization

(5)

(4)

Other [Member]

(1)

^[1]

(1)

Finite-lived intangible assets, gross carrying amount

Finite-lived intangible assets, accumulated amortization

(3)

(4)

Unfavorable agreements [Member]

Finite-lived intangible liabilities, gross carrying amount

Finite-lived intangible liabilities, accumulated amortization

$ (13)

$ (8)

[1]	Amortization associated with favorable lease agreements is recorded in Other operating expenses in the consolidated statements of comprehensive income
[2]	In-process research and development intangible assets acquired as part of the Merger on January 4, 2016 of $39 million ($36 million at the date placed into service due to changes in foreign currency exchange rates) had been placed in service during the year ended December 31, 2017 and are included as intangible assets acquired in this presentation.

Goodwill and Other Intangible Assets - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite-lived Intangible Assets [Roll Forward]
Amortization	$ 534	$ 581	$ 591
Acquired unfavorable lease liabilities, net	$ 21	$ 26
Weighted average remaining life of amortizable intangible assets	13 years 10 months 24 days

Goodwill and Other Intangible Assets - Schedule of Future Amortization Expense and Rent Offset (Details) $ in Millions	Dec. 31, 2018 USD ($)
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
2019	$ 472
2020	420
2021	344
2022	287
2023	239
Thereafter	1,547
Total	3,309
Rent offset
2019	(2)
2020	(2)
2021	(2)
2022	(3)
2023	(2)
Thereafter	(1)
Total	$ (12)

Derivative Financial Instruments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Loss on derivatives to be reclassified within the next twelve months	$ (12)
Maximum [Member]
Derivative [Line Items]
Longest outstanding maturity	2 years
Not Designated as Hedging Instrument [Member] \| Foreign exchange contracts [Member]
Derivative [Line Items]
Derivative, notional amount	$ 909	$ 971
Derivative asset, fair value	3	3
Not Designated as Hedging Instrument [Member] \| Foreign exchange contracts [Member] \| Other income, net [Member]
Derivative [Line Items]
Gain/(loss) recognized in income	0	11	$ (3)
Cash Flow Hedges [Member] \| Designated as Hedging Instrument [Member] \| Interest rate swaps [Member]
Derivative [Line Items]
Derivative, notional amount		300
Derivative liability, fair value		1
Cash Flow Hedges [Member] \| Designated as Hedging Instrument [Member] \| Foreign exchange contracts [Member]
Derivative [Line Items]
Derivative, notional amount	438	937
Derivative liability, fair value	15	21
(Loss)/gain recognized in OCI (effective element)	(22)	39	(127)
Loss reclassified from Accumulated OCL into income (effective element)	(28)	(53)	(42)
Loss recognized in income (ineffective portion and amount excluded from effectiveness testing)	$ (1)	$ (1)	$ (1)

Debt - Schedule of Long-term Debt (Details)
€ in Millions

12 Months Ended

Dec. 31, 2018

USD ($)

Dec. 31, 2018

EUR (€)

Sep. 10, 2018

Dec. 31, 2017

USD ($)

Short-term debt and current portion of long-term debt

$ 186,000,000

$ 85,000,000

7.000% senior notes due 2019 [Member]

4,389,000,000

4,450,000,000

Short-term debt and current portion of long-term debt

$ 186,000,000

186,000,000

7.00%

Term loan due 2019 [Member]

2019

Short-term debt and current portion of long-term debt

85,000,000

84,000,000

Revolving 1.25 Billion Dollar Credit Facility [Member]

2019

Revolving 1.25 Billion Dollar Credit Facility [Member] | Revolving Credit Facility [Member]

$ 130,000,000

884,000,000

5.750% senior notes due 2021 [Member]

^[1]

1,250,000,000

$ 498,000,000

497,000,000

5.75%

3.500% senior notes due 2021 [Member]

2021

$ 448,000,000

447,000,000

3.50%

2.125% senior notes due 2022 [Member]

2021

$ 615,000,000

^[1]

€ 540

644,000,000

^[1]

^[1]

2.125%

4.625% senior notes due 2023 [Member]

^[1]

2022

$ 248,000,000

248,000,000

4.625%

3.600% senior notes due 2024 [Member]

2023

$ 645,000,000

645,000,000

3.60%

4.400% senior notes due 2026 [Member]

2024

$ 544,000,000

544,000,000

4.40%

4.500% senior notes due 2028 [Member]

2026

$ 595,000,000

4.50%

6.125% senior notes due 2043 [Member]

2028

$ 271,000,000

6.125%

5.050% senior notes due 2048 [Member]

2043

$ 395,000,000

5.05%

2048

[1]	Notes issued in Euro (€540 million)

Debt - Narrative (Details)

1 Months Ended

2 Months Ended

3 Months Ended

12 Months Ended

Sep. 10, 2018

USD ($)

May 16, 2017

USD ($)

Mar. 28, 2017

USD ($)

Mar. 07, 2017

USD ($)

May 26, 2016

USD ($)

May 26, 2016

EUR (€)

Mar. 22, 2016

USD ($)

Jan. 04, 2016

USD ($)

Dec. 28, 2015

USD ($)

Dec. 19, 2015

USD ($)

Dec. 19, 2015

EUR (€)

Nov. 20, 2015

USD ($)

tranche

Mar. 28, 2007

USD ($)

Aug. 31, 2013

USD ($)

Mar. 07, 2017

USD ($)

Sep. 30, 2018

USD ($)

Dec. 31, 2018

USD ($)

Dec. 31, 2017

USD ($)

Mar. 07, 2017

EUR (€)

May 26, 2016

EUR (€)

Mar. 15, 2016

Nov. 20, 2015

EUR (€)

Aug. 15, 2013

USD ($)

Mar. 31, 2011

USD ($)

Mar. 11, 2011

USD ($)

Sep. 30, 2009

USD ($)

Description of interest accrual date

Interest has accrued on both the 2028 senior notes and 2048 senior notes from September 10, 2018 and will be paid in cash on March 15 and September 15 of each year, commencing on March 15, 2019.

Proceeds from Debt, Net of Issuance Costs

$ 989,000,000

Revolving Credit Facility [Member] | Trinity Acquisition plc [Member]

Term loan due 2019 [Member]

$ 1,250,000,000

Prepayment of outstanding debt

$ 127,000,000

5.750% senior notes due 2021 [Member]

5.750% senior notes due 2021 [Member] | Senior Notes [Member]

5.75%

5.75%

$ 500,000,000

7.000% senior notes due 2019 [Member]

5.871%

7.000% senior notes due 2019 [Member] | Senior Notes [Member]

7.00%

7.00%

Repayments of Debt

$ 113,000,000

$ 300,000,000

3.600% senior notes due 2024 [Member]

7.081%

4.500% senior notes due 2028 [Member]

3.60%

4.50%

$ 600,000,000

4.504%

5.050% senior notes due 2048 [Member]

Sep. 15, 2028

5.05%

$ 400,000,000

5.073%

4.625% senior notes due 2023 [Member]

Sep. 15, 2048

4.625% senior notes due 2023 [Member] | Senior Notes [Member]

4.625%

4.625%

$ 250,000,000

6.125% senior notes due 2043 [Member]

4.696%

6.125% senior notes due 2043 [Member] | Senior Notes [Member]

6.125%

6.125%

$ 275,000,000

3.500% senior notes due 2021 [Member]

6.154%

3.500% senior notes due 2021 [Member] | Senior Notes [Member]

3.50%

3.50%

$ 450,000,000

4.400% senior notes due 2026 [Member]

3.707%

4.400% senior notes due 2026 [Member] | Senior Notes [Member]

4.40%

4.40%

$ 550,000,000

2.125% senior notes due 2022 [Member]

4.572%

2.125% senior notes due 2022 [Member] | Senior Notes [Member]

^[1]

2.125%

2.125%

2.154%

Description of interest accrual date

May 26, 2022

Interest has accrued on the notes from May 26, 2016 and will be paid in cash on May 26 of each year.

Proceeds from long-term debt issuance

$ 600,000,000

€ 535,000,000

2.125% senior notes due 2022 [Member] | Senior Notes [Member] | Trinity Acquisition plc [Member]

Revolving 1.25 Billion Dollar Credit Facility [Member] | Revolving Credit Facility [Member]

$ 609,000,000

€ 540,000,000

Revolving 1.25 Billion Dollar Credit Facility [Member] | Line of Credit [Member] | Revolving Credit Facility [Member]

^[1]

$ 1,250,000,000

Line of credit maturity date

$ 1,250,000,000

1,250,000,000

$ 1,250,000,000

Mar. 07, 2022

Long-term borrowings outstanding

$ 409,000,000

409,000,000

€ 45,000,000

Revolving 1.25 Billion Dollar Credit Facility [Member] | Line of Credit [Member] | Revolving Credit Facility [Member] | LIBOR [Member] | Minimum [Member]

Revolving 1.25 Billion Dollar Credit Facility [Member] | Line of Credit [Member] | Revolving Credit Facility [Member] | LIBOR [Member] | Maximum [Member]

1.00%

Revolving 1.25 Billion Dollar Credit Facility [Member] | Line of Credit [Member] | Revolving Credit Facility [Member] | Bank Base Rate [Member] | Minimum [Member]

1.75%

Revolving 1.25 Billion Dollar Credit Facility [Member] | Line of Credit [Member] | Revolving Credit Facility [Member] | Bank Base Rate [Member] | Maximum [Member]

0.00%

Revolving $800 million Credit Facility [Member] | Line of Credit [Member] | Revolving Credit Facility [Member]

0.75%

Current borrowing capacity

$ 800,000,000

800,000,000

800,000,000

6.200% senior notes due 2017 [Member] | Senior Notes [Member]

6.20%

Repayments of Debt

$ 407,000,000

$ 206,000,000

$ 600,000,000

6.253%

3.600% senior notes due 2024 [Member] | Senior Notes [Member]

10 years

3.60%

$ 650,000,000

3.614%

Description of interest accrual date

May 15, 2024

Interest accrues on the 2024 senior notes from May 16, 2017 and will be paid in cash on May 15 and November 15 of each year.

Proceeds from Debt, Net of Issuance Costs

$ 644,000,000

Senior Notes Due 2021 and 2026 [Member] | Senior Notes [Member]

Proceeds from long-term debt issuance

$ 988,000,000

Revolving $800 million Credit Facility [Member] | Line of Credit [Member] | Revolving Credit Facility [Member]

Current borrowing capacity

800,000,000

$ 800,000,000

Repayment of line of credit

300,000,000

Revolving $800 million Credit Facility [Member] | Line of Credit [Member] | Revolving Credit Facility [Member] | LIBOR [Member] | Minimum [Member]

1.375%

Revolving $800 million Credit Facility [Member] | Line of Credit [Member] | Revolving Credit Facility [Member] | LIBOR [Member] | Maximum [Member]

1.25%

Revolving $800 million Credit Facility [Member] | Line of Credit [Member] | Revolving Credit Facility [Member] | Bank Base Rate [Member] | Minimum [Member]

2.00%

Revolving $800 million Credit Facility [Member] | Line of Credit [Member] | Revolving Credit Facility [Member] | Bank Base Rate [Member] | Maximum [Member]

0.25%

4.125% Senior Notes Due 2016 [Member] | Senior Notes [Member]

1.00%

4.125% Senior Notes Due 2016 [Member] | Senior Notes [Member]

4.125%

4.125%

$ 300,000,000

Senior notes repaid month and year

4.24%

2016-03

1-year Term Loan Facility Matures 2016, Tranche two [Member] | Line of Credit [Member] | Notes Payable [Member]

Repayment of line of credit

$ 400,000,000

Amounts drawn on line of credit

$ 400,000,000

1-year Term Loan Facility Matures 2016 [Member] | Line of Credit [Member] | Notes Payable [Member]

Term loan due 2019 [Member] | Notes Payable [Member]

1 year

Prepayment of outstanding debt

$ 340,000,000

$ 127,000,000

Proceeds from long-term debt issuance

$ 340,000,000

4 years

Debt Instrument, Credit Rating

BBB/Baa3

7-year term loan facility [Member] | Notes Payable [Member]

1-year Term Loan Facility Matures 2016, Tranche one [Member] | Line of Credit [Member] | Notes Payable [Member]

7 years

Quarterly payment

$ 6,000,000

Final payment of debt

$ 186,000,000

Maximum borrowing capacity | €

€ 550,000,000

Number of tranches | tranche

1 year

Amounts drawn on line of credit

$ 592,000,000

€ 544,000,000

[1]	Notes issued in Euro (€540 million)

Debt - Maturities Of Long Term Debt (Details) $ in Millions	Dec. 31, 2018 USD ($)
Debt Instrument [Line Items]
2019	$ 378
2020	181
2021	1,103
2022	875
2023	369
Thereafter	3,494
Total	6,400
Senior Notes [Member]
Debt Instrument [Line Items]
2019	187
2020	0
2021	950
2022	617
2023	250
Thereafter	2,475
Total	4,479
Senior Notes [Member] \| Interest on Senior Notes [Member]
Debt Instrument [Line Items]
2019	191
2020	181
2021	153
2022	128
2023	119
Thereafter	1,019
Total	1,791
Revolving Credit Facility [Member] \| Line of Credit [Member] \| Revolving $1.25 Billion Credit Facility [Member]
Debt Instrument [Line Items]
2019	0
2020	0
2021	0
2022	130
2023	0
Thereafter	0
Total	$ 130

Debt - Interest Expense (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

$ 208

$ 188

$ 184

Senior Notes [Member]

166

148

139

Term Loan

Other (i) [Member]

Revolving Credit Facility [Member] | Line of Credit [Member] | Revolving 1.25 Billion Dollar Credit Facility [Member]

^[1]

Revolving Credit Facility [Member] | Line of Credit [Member] | WSI Revolving Credit Facility [Member]

$ 26

$ 1

$ 2

[1]	Other primarily includes debt issuance costs, interest expense on capitalized leases and accretion on deferred and contingent consideration.

Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) $ in Millions	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Contingent consideration [Member] \| Fair Value Inputs, Discount Rate [Member]
Liabilities:
Fair Value Inputs, Discount Rate	9.92	9.64
Recurring [Member]
Assets:
Mutual funds / exchange traded funds	$ 18	$ 40
Derivative financial instruments	5	18
Liabilities:
Contingent consideration	51	51
Derivative financial instruments	17	37
Recurring [Member] \| Level 1 [Member]
Assets:
Mutual funds / exchange traded funds	18	40
Derivative financial instruments	0	0
Liabilities:
Contingent consideration	0	0
Derivative financial instruments	0	0
Recurring [Member] \| Level 2 [Member]
Assets:
Mutual funds / exchange traded funds	0	0
Derivative financial instruments	5	18
Liabilities:
Contingent consideration	0	0
Derivative financial instruments	17	37
Recurring [Member] \| Level 3 [Member]
Assets:
Mutual funds / exchange traded funds	0	0
Derivative financial instruments	0	0
Liabilities:
Contingent consideration	51	51
Derivative financial instruments	$ 0	$ 0

Fair Value Measurements - Fair Value Liabilities Measured Using Significant Unobservable Inputs Level 3 (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance as of beginning of period	$ 51
Obligations assumed	2
Payments	(3)
Realized and unrealized gains	3
Foreign exchange	(2)
Balance as of end of period	$ 51

Fair Value Measurements - Schedule of Liabilities Whose Carrying Values Differ From the Fair Value and are Not Measured on a Recurring Basis (Details) - Nonrecurring [Member] - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt and current portion of long-term debt	$ 186	$ 85
Long-term debt	4,389	4,450
Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt and current portion of long-term debt	191	85
Long-term debt	$ 4,458	$ 4,706

Retirement Benefits - Narrative (Details) $ in Millions	6 Months Ended	12 Months Ended
Retirement Benefits - Narrative (Details) $ in Millions	Dec. 31, 2017	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Portion of pension and OPEB obligation attributed to disclosed plans (as a percent)		99.00%
Defined contribution plan expenses		$ 150	$ 154	$ 152
Change in Assumptions for Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Credit to net periodic benefit income				51
Accounting Standards Update 2017-07 [Member]
Defined Benefit Plan Disclosure [Line Items]
Reclassification For Presentation		$ 280	222	203
PRW [Member]
Defined Benefit Plan Disclosure [Line Items]
Curtailment			0	0
Settlement			0	0
Average remaining service period		10 years 7 months 6 days
UNITED STATES [Member]
Defined Benefit Plan Disclosure [Line Items]
Vesting period		2 years
UNITED STATES [Member] \| Defined Contribution Plan Tranche One [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution, percent of match		100.00%
Maximum annual contributions per employee, percent		1.00%
UNITED STATES [Member] \| Defined Contribution Plan Tranche Two [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution, percent of match		50.00%
Maximum annual contributions per employee, percent		5.00%
UNITED STATES [Member] \| Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Curtailment			0	0
Settlement		$ (1)	(1)	0
UNITED KINGDOM [Member] \| Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan employees covered percentage		33.33%
Curtailment			0	0
Settlement		$ (41)	(37)	$ 0
UNITED KINGDOM [Member] \| Pension Plan [Member] \| Pension Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlement		(40)	$ (36)
NETHERLANDS [Member] \| Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Curtailment		$ 16
Newly-eligible employees [Member] \| UNITED STATES [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan required employee contribution rate	0.02

Retirement Benefits - Change in Benefit Obligation and Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Change in Plan Assets
Fair value of plan assets, beginning of year	$ 9,128
Fair value of plan assets, end of year	8,292	$ 9,128
Pension benefits assets	773	764
Non-current liability for pension benefits	(1,170)	(1,259)
Pension Plan [Member] \| UNITED STATES [Member]
Change in Benefit Obligation
Benefit obligation, beginning of year	4,476	4,169
Service cost	66	66	$ 59
Interest cost	140	139	137
Employee contributions	14	6
Actuarial (gains)/losses	(313)	293
Settlements	(11)	(16)
Benefits paid	(185)	(181)
Transfers in		0
Foreign currency changes		0
Benefit obligation, end of year	4,187	4,476	4,169
Change in Plan Assets
Fair value of plan assets, beginning of year	3,654	3,280
Actual return on plan assets	(157)	464
Employer contributions	88	101
Employee contributions	14	6
Settlements	(11)	(16)
Benefits paid	(185)	(181)
Transfers in		0
Foreign currency adjustment		0
Fair value of plan assets, end of year	3,403	3,654	3,280
Funded status at end of year	(784)	(822)
Accumulated Benefit Obligation	4,187	4,476
Pension benefits assets		0
Current liability for pension benefits	(49)	(40)
Non-current liability for pension benefits	(735)	(782)
Components on the Consolidated Balance Sheet	(784)	(822)
Pension Plan [Member] \| UNITED KINGDOM [Member]
Change in Benefit Obligation
Benefit obligation, beginning of year	4,165	3,899
Service cost	18	32	24
Interest cost	95	93	114
Employee contributions	1	1
Actuarial (gains)/losses	(176)	2
Settlements	(152)	(138)
Benefits paid	(96)	(93)
Plan amendments	40
Transfers in		0
Foreign currency changes	(229)	369
Benefit obligation, end of year	3,666	4,165	3,899
Change in Plan Assets
Fair value of plan assets, beginning of year	4,910	4,360
Actual return on plan assets	(69)	290
Employer contributions	85	66
Employee contributions	1	1
Settlements	(152)	(138)
Benefits paid	(96)	(93)
Transfers in		0
Foreign currency adjustment	(277)	424
Fair value of plan assets, end of year	4,402	4,910	4,360
Funded status at end of year	736	745
Accumulated Benefit Obligation	3,666	4,165
Pension benefits assets	745	754
Current liability for pension benefits	(1)	0
Non-current liability for pension benefits	(8)	(9)
Components on the Consolidated Balance Sheet	736	745
Pension Plan [Member] \| Other Foreign Plans [Member]
Change in Benefit Obligation
Benefit obligation, beginning of year	822	732
Service cost	21	20	19
Interest cost	18	17	18
Employee contributions		0
Actuarial (gains)/losses	(7)	5
Settlements	(26)	(1)
Curtailments	(20)
Benefits paid	(28)	(29)
Transfers in	1	1
Foreign currency changes	(53)	77
Benefit obligation, end of year	728	822	732
Change in Plan Assets
Fair value of plan assets, beginning of year	562	467
Actual return on plan assets	(9)	42
Employer contributions	22	34
Employee contributions		0
Settlements	(26)	(1)
Benefits paid	(28)	(29)
Transfers in	1	1
Foreign currency adjustment	(36)	48
Fair value of plan assets, end of year	486	562	467
Funded status at end of year	(242)	(260)
Accumulated Benefit Obligation	698	790
Pension benefits assets	17	17
Current liability for pension benefits	(6)	(6)
Non-current liability for pension benefits	(253)	(271)
Components on the Consolidated Balance Sheet	(242)	(260)
PRW [Member]
Change in Benefit Obligation
Benefit obligation, beginning of year	123	113
Service cost	1	0	1
Interest cost	4	4	3
Employee contributions	7	6
Actuarial (gains)/losses	(3)	14
Settlements		0
Benefits paid	(14)	(14)
Plan amendments	(31)
Transfers in		0
Foreign currency changes		0
Benefit obligation, end of year	87	123	113
Change in Plan Assets
Fair value of plan assets, beginning of year	2	4
Actual return on plan assets		0
Employer contributions	6	6
Employee contributions	7	6
Settlements		0
Benefits paid	(14)	(14)
Transfers in		0
Foreign currency adjustment		0
Fair value of plan assets, end of year	1	2	$ 4
Funded status at end of year	(86)	(121)
Accumulated Benefit Obligation	87	123
Pension benefits assets		0
Current liability for pension benefits	(5)	(5)
Non-current liability for pension benefits	(81)	(116)
Components on the Consolidated Balance Sheet	$ (86)	$ (121)

Retirement Benefits - Amounts Recognized in Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Pension Plan [Member] \| UNITED STATES [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ 769	$ 663
Accumulated other comprehensive loss/(income)	769	663
Pension Plan [Member] \| UNITED KINGDOM [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	955	909
Net prior service gain	(76)	(142)
Accumulated other comprehensive loss/(income)	879	767
Pension Plan [Member] \| Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	98	79
Accumulated other comprehensive loss/(income)	98	79
PRW [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	16	19
Net prior service gain	(31)
Accumulated other comprehensive loss/(income)	$ (15)	$ 19

Retirement Benefits - Benefit Obligation In Excess Of Plan Assets (Details) - Pension Plan [Member] - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
UNITED STATES [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	$ 4,187	$ 4,476
Fair value of plan assets at end of year	3,403	3,654
UNITED KINGDOM [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	9	10
Fair value of plan assets at end of year		0
Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	672	758
Fair value of plan assets at end of year	$ 413	$ 481

Retirement Benefits - Accumulated Benefit Obligation In Excess of Plan Assets (Details) - Pension Plan [Member] - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
UNITED STATES [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	$ 4,187	$ 4,476
Accumulated benefit obligation at end of year	4,187	4,476
Fair value of plan assets at end of year	3,403	3,654
UNITED KINGDOM [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	9	10
Accumulated benefit obligation at end of year	9	10
Fair value of plan assets at end of year		0
Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	672	758
Accumulated benefit obligation at end of year	642	726
Fair value of plan assets at end of year	$ 413	$ 481

Retirement Benefits - Net Periodic Benefit Cost (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Pension Plan [Member] | UNITED STATES [Member]

^[1]

$ (280)

$ (222)

$ (203)

140

139

137

(273)

(245)

(240)

(55)

(26)

(32)

117

238

(11)

(13)

(12)

(1)

Total recognized in other comprehensive loss/(income)

105

226

Total recognized in net periodic benefit (income)/cost and other comprehensive loss/(income)

194

Pension Plan [Member] | UNITED KINGDOM [Member]

114

(298)

(284)

(253)

(19)

(18)

(19)

(118)

(87)

(92)

191

(4)

323

(45)

(53)

(42)

(41)

(37)

Total recognized in other comprehensive loss/(income)

164

(76)

300

Total recognized in net periodic benefit (income)/cost and other comprehensive loss/(income)

(163)

208

Pension Plan [Member] | Other Foreign Plans [Member]

(31)

(30)

(27)

(16)

(4)

(7)

(2)

(2)

(1)

(8)

Total recognized in other comprehensive loss/(income)

(10)

Total recognized in net periodic benefit (income)/cost and other comprehensive loss/(income)

PRW [Member]

(3)

(31)

Total recognized in other comprehensive loss/(income)

(34)

Total recognized in net periodic benefit (income)/cost and other comprehensive loss/(income)

$ (29)

$ 18

$ 8

[1]

Retirement Benefits - Amounts in AOCI to be Recognized Next Fiscal Year (Details) $ in Millions	Dec. 31, 2018 USD ($)
Pension Plan [Member] \| UNITED STATES [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated net actuarial loss	$ (19)
Pension Plan [Member] \| UNITED KINGDOM [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated net actuarial loss	(21)
Prior service credit	(16)
Pension Plan [Member] \| Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated net actuarial loss	(2)
PRW [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated net actuarial loss	(1)
Prior service credit	$ (4)

Retirement Benefits - Assumptions Used (Details)	12 Months Ended
Retirement Benefits - Assumptions Used (Details)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Plan [Member] \| UNITED STATES [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate - PBO	3.60%	4.00%	4.20%
Discount rate - service cost	3.50%	3.90%	3.90%
Discount rate - interest cost on service cost	3.10%	3.20%	3.20%
Discount rate - interest cost on PBO	3.20%	3.40%	3.40%
Expected long-term rate of return on assets	7.60%	7.60%	7.60%
Rate of increase in compensation levels	4.30%	4.30%	4.30%
Discount rate	4.20%	3.60%
Rate of increase in compensation levels	4.30%	4.30%
Pension Plan [Member] \| UNITED KINGDOM [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate - PBO	2.60%	2.60%	3.80%
Discount rate - service cost	2.70%	2.60%	3.80%
Discount rate - interest cost on service cost	2.50%	2.40%	3.80%
Discount rate - interest cost on PBO	2.30%	2.30%	3.40%
Expected long-term rate of return on assets	6.20%	6.30%	6.20%
Rate of increase in compensation levels	3.00%	3.20%	3.20%
Discount rate	2.80%	2.60%
Rate of increase in compensation levels	3.00%	3.00%
Pension Plan [Member] \| Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate - PBO	2.60%	2.70%	3.20%
Discount rate - service cost	2.90%	3.00%	3.40%
Discount rate - interest cost on service cost	2.70%	2.80%	3.10%
Discount rate - interest cost on PBO	2.30%	2.30%	2.80%
Expected long-term rate of return on assets	5.70%	6.10%	6.10%
Rate of increase in compensation levels	2.30%	2.30%	2.30%
Discount rate	2.80%	2.60%
Rate of increase in compensation levels	2.30%	2.30%
PRW [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate - PBO	3.50%	4.00%	4.20%
Discount rate - service cost	3.50%	3.90%	4.10%
Discount rate - interest cost on service cost	3.20%	3.50%	3.50%
Discount rate - interest cost on PBO	3.10%	3.30%	3.30%
Expected long-term rate of return on assets	2.00%	2.00%	2.00%
Health care cost trend - Initial rate	6.50%	7.00%	7.00%
Health care cost trend - Ultimate rate	5.00%	5.00%	5.00%
Health care cost trend - ultimate rate year	2022	2022	2022
Discount rate	4.20%	3.50%

Retirement Benefits - Fair Value Reconciliation (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Compensation And Retirement Disclosure [Abstract]
Net assets held in investments	$ 8,279	$ 9,121
PRW plan assets	1	2
Net (payable)/receivable for investments purchased	(1)	2
Dividend and interest receivable	1	3
Other adjustments	12
Fair value of plan assets	$ 8,292	$ 9,128

Retirement Benefits - Significant Unobservable Input Reconciliation (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets, beginning of year	$ 9,128
Fair value of plan assets, end of year	8,292
Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets, beginning of year	19
Plan termination	(17)
Fair value of plan assets, end of year	$ 2

Retirement Benefits - Projected Benefit Obligation (Details) - Pension Plan [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
UNITED STATES [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 88	$ 101
UNITED STATES [Member] \| Qualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected future employer contributions, next fiscal year	60
Employer contributions	50	50
UNITED KINGDOM [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	85	66
UNITED KINGDOM [Member] \| Qualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected future employer contributions, next fiscal year	75
Employer contributions	84	65
Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	22	34
Other Foreign Plans [Member] \| Qualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected future employer contributions, next fiscal year	23
Employer contributions	$ 14	$ 13

Retirement Benefits - Expected Benefit Payments (Details) $ in Millions	Dec. 31, 2018 USD ($)
Defined Benefit Plan Disclosure [Line Items]
2019	$ 413
2020	392
2021	415
2022	428
2023	445
Years 2024 – 2028	2,390
Expected future benefit payments, total	4,483
Pension Plan [Member] \| UNITED STATES [Member]
Defined Benefit Plan Disclosure [Line Items]
2019	263
2020	250
2021	263
2022	272
2023	280
Years 2024 – 2028	1,435
Expected future benefit payments, total	2,763
Pension Plan [Member] \| UNITED KINGDOM [Member]
Defined Benefit Plan Disclosure [Line Items]
2019	109
2020	107
2021	116
2022	119
2023	127
Years 2024 – 2028	735
Expected future benefit payments, total	1,313
Pension Plan [Member] \| Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
2019	28
2020	25
2021	25
2022	26
2023	27
Years 2024 – 2028	160
Expected future benefit payments, total	291
PRW [Member]
Defined Benefit Plan Disclosure [Line Items]
2019	13
2020	10
2021	11
2022	11
2023	11
Years 2024 – 2028	60
Expected future benefit payments, total	$ 116

Commitments and Contingencies - Narrative (Details)																					1 Months Ended	3 Months Ended		12 Months Ended
Commitments and Contingencies - Narrative (Details)	Jun. 05, 2018 USD ($)	Sep. 12, 2016 USD ($) plaintiff	Aug. 05, 2016 USD ($) plaintiff	Mar. 31, 2016 USD ($)	Jul. 21, 2015	Jul. 15, 2015	Aug. 01, 2014 USD ($)	Jan. 10, 2014 plaintiff	Oct. 01, 2013 USD ($)	Aug. 06, 2013 plaintiff	Jun. 20, 2013 lawsuit	Jun. 11, 2013 lawsuit	Jun. 03, 2013 lawsuit	Feb. 14, 2013 USD ($) plaintiff lawsuit	Feb. 08, 2013 USD ($) plaintiff	Mar. 11, 2011 USD ($) plaintiff	Sep. 16, 2010 USD ($) plaintiff	Sep. 14, 2009 USD ($) plaintiff	Aug. 06, 2009 USD ($)	Jul. 02, 2009 USD ($)	Apr. 30, 2018 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jul. 01, 2017 USD ($)	May 08, 2017 USD ($)	Mar. 01, 2017 USD ($)	Mar. 25, 2014 action
Loss Contingencies [Line Items]
Rent expense, exclusive of sublease income																								$ 295,000,000	$ 302,000,000	$ 302,000,000
Sublease income																								15,000,000	21,000,000	17,000,000
Capital lease obligations																								43,000,000	48,000,000
Operating leases																								1,351,000,000
Business combination, deferred and contingent consideration																								83,000,000
Payments for deferred contingent consideration, financing activities																								50,000,000	65,000,000	$ 67,000,000
Amount payable from option																								33,000,000
Settled Litigation [Member] \| Troice, et al. v. Willis of Colorado, Inc., et al. [Member]
Loss Contingencies [Line Items]
Damages sought (in excess of)																				$ 1,000,000,000
Number of actions consolidated \| action																														2
Settled Litigation [Member] \| Janvey, et al. v. Willis of Colorado, Inc., et al. [Member]
Loss Contingencies [Line Items]
Damages sought (in excess of)									$ 1,000,000,000
Total losses incurred by plaintiff									$ 4,600,000,000
Settled Litigation [Member] \| Stanford Financial Group [Member]
Loss Contingencies [Line Items]
Provision for litigation losses																						$ 50,000,000	$ 70,000,000
Litigation settlement amount				$ 120,000,000																		$ 120,000,000
Settled Litigation [Member] \| City of Houston [Member]
Loss Contingencies [Line Items]
Litigation settlement amount																					$ 40,000,000
Increase to actuarial accrued liability alleged by plaintiff							$ 163,000,000
Estimated damages incurred (through July 1, 2017)																												$ 430,000,000
Estimated future damages incurred (as of July 1, 2017)																											$ 400,000,000
Settled Litigation [Member] \| Elma Sanchez, et al. [Member]
Loss Contingencies [Line Items]
Number of plaintiffs \| plaintiff								3		3
Litigation settlement amount	$ 9,750,000
Premium rate increase										85.00%
Litigation settlement amount payable																													$ 9,750,000
Pending Litigation [Member] \| Canabal, et al. v. Willis of Colorado, Inc., et al. [Member]
Loss Contingencies [Line Items]
Damages sought (in excess of)																			$ 1,000,000,000
Pending Litigation [Member] \| Rupert, et al. v. Winter, et al. [Member]
Loss Contingencies [Line Items]
Damages sought (in excess of)																		$ 300,000,000
Number of plaintiffs \| plaintiff																		97
Pending Litigation [Member] \| Casanova, et al. v. Willis of Colorado, Inc., et al. [Member]
Loss Contingencies [Line Items]
Damages sought (in excess of)																	$ 5,000,000
Number of plaintiffs \| plaintiff																	7
Pending Litigation [Member] \| Rishmague, et ano. v. Winter, et al. [Member]
Loss Contingencies [Line Items]
Damages sought (in excess of)																$ 37,000,000
Number of plaintiffs \| plaintiff																2
Pending Litigation [Member] \| MacArthur v. Winter, et al. [Member]
Loss Contingencies [Line Items]
Damages sought (in excess of)															$ 4,000,000
Number of plaintiffs \| plaintiff															2
Pending Litigation [Member] \| Stanford Financial Group, Florida Suits [Member]
Loss Contingencies [Line Items]
Number of complaints filed \| lawsuit														5
Number of cases removed \| lawsuit													5
Number of cases moved to stay \| lawsuit												4
Number of cases transferred \| lawsuit											5
Claims stayed, period											7 days
Pending Litigation [Member] \| Barbar, et al. v. Willis Group Holdings Public Limited Company, et al. [Member]
Loss Contingencies [Line Items]
Damages sought (in excess of)														$ 30,000,000
Number of plaintiffs \| plaintiff														35
Pending Litigation [Member] \| de Gadala-Maria, et al. v. Willis Group Holdings Public Limited Company, et al. [Member]
Loss Contingencies [Line Items]
Damages sought (in excess of)														$ 83,500,000
Number of plaintiffs \| plaintiff														64
Period to replead dismissed claim					21 days
Pending Litigation [Member] \| Ranni, et ano. v. Willis Group Holdings Public Limited Company, et al. [Member]
Loss Contingencies [Line Items]
Damages sought (in excess of)														$ 3,000,000
Number of plaintiffs \| plaintiff														2
Pending Litigation [Member] \| Tisminesky, et al. v. Willis Group Holdings Public Limited Company, et al. [Member]
Loss Contingencies [Line Items]
Damages sought (in excess of)														$ 6,500,000
Number of plaintiffs \| plaintiff														11
Period to replead dismissed claim					21 days
Pending Litigation [Member] \| Zacarias, et al. v. Willis Group Holdings Public Limited Company, et al. [Member]
Loss Contingencies [Line Items]
Damages sought (in excess of)														$ 12,500,000
Number of plaintiffs \| plaintiff														10
Period to replead dismissed claim						21 days
Pending Litigation [Member] \| Martin v. Willis of Colorado, Inc., et. al. [Member]
Loss Contingencies [Line Items]
Damages sought (in excess of)		$ 1,000,000	$ 100,000
Number of plaintiffs \| plaintiff		5	1
Pending Litigation [Member] \| Abel, et al. v. Willis of Colorado, Inc., et al [Member]
Loss Contingencies [Line Items]
Damages sought (in excess of)		$ 135,000,000
Number of plaintiffs \| plaintiff		300
Trident V Parallel Fund [Member]
Loss Contingencies [Line Items]
Capital contribution																								2,000,000
Alston, Gayler and Miller Insurance Services LLP [Member]
Loss Contingencies [Line Items]
Business combination, contingent consideration, liability																								73,000,000
Property Lease Guarantee [Member]
Loss Contingencies [Line Items]
Capital lease obligations																								7,000,000	8,000,000
Operating leases																								$ 570,000,000	$ 669,000,000

Commitments and Contingencies - Future Minimum Rental Commitments Under all Non-Cancellable Operating Lease Agreements (Details) $ in Millions	Dec. 31, 2018 USD ($)
Commitments And Contingencies Disclosure [Abstract]
Gross rental commitments due 2019	$ 197
Gross rental commitments due 2020	180
Gross rental commitments due 2021	159
Gross rental commitments due 2022	142
Gross rental commitments due 2023	131
Thereafter	542
Gross rental commitments due	1,351
Rentals from subleases due 2019	(11)
Rentals from subleases due 2020	(11)
Rentals from subleases due 2021	(8)
Rentals from subleases due 2022	(2)
Rentals from subleases due 2023	(2)
Rentals from subleases due Thereafter	(8)
Rentals from subleases due	(42)
Net rental commitments due 2019	186
Net rental commitments due 2020	169
Net rental commitments due 2021	151
Net rental commitments due 2022	140
Net rental commitments due 2023	129
Net rental commitments due Thereafter	534
Net rental commitments due	$ 1,309

Supplementary Information for Certain Balance Sheet Accounts - Prepaid and Other Current Assets (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Prepayments and accrued income	$ 136	$ 132
Deferred contract costs	102
Derivatives and investments	25	29
Deferred compensation plan assets	18	21
Retention incentives	5	7
Corporate income and other taxes	61	170
Other current assets	57	71
Total prepaid and other current assets	$ 404	$ 430

Supplementary Information for Certain Balance Sheet Accounts - Other non - Current Assets (Details) - USD ($) $ in Millions	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Prepayments and accrued income	$ 14		$ 18
Deferred contract costs	46
Deferred compensation plan assets	125		135
Deferred tax assets	59		46
Accounts receivable, net	20	$ 33	33
Other investments	7		26
Other non-current assets	196		189
Total other non-current assets	$ 467		$ 447

Supplementary Information for Certain Balance Sheet Accounts - Deferred Revenue and Accrued Expenses (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Accounts payable, accrued liabilities and deferred income	$ 691	$ 772
Discretionary compensation	321	313
Accrued compensation	437	439
Accrued vacation	111	93
Other employee-related liabilities	87	94
Total deferred revenue and accrued expenses	$ 1,647	$ 1,711

Supplementary Information for Certain Balance Sheet Accounts - Other Current Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Accounts payable	$ 163	$ 136
Income and other taxes payable	129	90
Contingent and deferred consideration on acquisitions	61	55
Payroll-related liabilities	210	209
Derivatives	13	32
Third party commissions	169	172
Other current liabilities	119	110
Total other current liabilities	$ 864	$ 804

Supplementary Information for Certain Balance Sheet Accounts - Provision For Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Claims, lawsuits and other proceedings	$ 455	$ 474
Other provisions	85	84
Total provision for liabilities	$ 540	$ 558

Supplementary Information for Certain Balance Sheet Accounts - Other Non-current Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Incentives from lessors	$ 120	$ 138
Deferred compensation plan liability	125	135
Contingent and deferred consideration on acquisitions	22	41
Liabilities for uncertain tax positions	46	60
Lease-related liabilities	29	28
Other non-current liabilities	87	142
Total other non-current liabilities	$ 429	$ 544

Other Income, Net (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Other Income And Expenses [Abstract]

(Loss)/gain on disposal of operations

$ (9)

$ 13

$ 2

Net periodic pension and postretirement benefit credits

^[1]

280

222

203

Interest in earnings of associates

^[2]

Impact of Venezuelan currency devaluation

(2)

Foreign exchange loss

(24)

(72)

(29)

Other income, net

$ 250

$ 164

$ 178

[1]

[2]

Beginning in 2018, the Company retrospectively reclassified the pre-tax effect of its interest in earnings of associates from its own line item to other income, net within its consolidated statements of comprehensive income

Accumulated Other Comprehensive Loss - Components of Other Comprehensive (Loss) Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive (loss)/income, before tax	$ (504)	$ 388	$ (993)
Other comprehensive (loss)/income, tax	56	(4)	126
Other comprehensive (loss)/income, net of tax, before non-controlling interests	(448)	384	(867)
Foreign currency translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive (loss)/income, before tax	(251)	295	(353)
Other comprehensive (loss)/income, tax	0	0	0
Other comprehensive (loss)/income, net of tax, before non-controlling interests	(251)	295	(353)
Defined pension and post-retirement benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive (loss)/income, before tax	(258)	3	(553)
Other comprehensive (loss)/income, tax	59	11	114
Other comprehensive (loss)/income, net of tax, before non-controlling interests	(199)	14	(439)
Derivative instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive (loss)/income, before tax	5	90	(87)
Other comprehensive (loss)/income, tax	(3)	(15)	12
Other comprehensive (loss)/income, net of tax, before non-controlling interests	2	75	(75)
AOCI Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive (loss)/income, before tax	0	(13)	20
Other comprehensive (loss)/income, tax	0	0	0
Other comprehensive (loss)/income, net of tax, before non-controlling interests	0	(13)	20
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive (loss)/income, before tax	(504)	375	(973)
Other comprehensive (loss)/income, tax	56	(4)	126
Other comprehensive (loss)/income, net of tax, before non-controlling interests	$ (448)	$ 371	$ (847)

Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

AOCI Attributable to Parent, Net of Tax [Roll Forward]

Other comprehensive (loss)/income before reclassifications

$ 10,249

^[1]

$ 10,183

$ 2,360

(514)

287

(929)

Amounts reclassified from accumulated other comprehensive income/(loss) (net of income tax)

(448)

371

(847)

Reclassification from AOCI, Current Period, Tax

9,971

^[1]

10,249

^[1]

10,183

Foreign currency translation [Member]

AOCI Attributable to Parent, Net of Tax [Roll Forward]

Other comprehensive (loss)/income before reclassifications

(365)

(650)

(314)

(251)

285

(336)

Amounts reclassified from accumulated other comprehensive income/(loss) (net of income tax)

(251)

285

(336)

Gains and losses on cash flow hedges [Member]

(616)

(365)

(650)

AOCI Attributable to Parent, Net of Tax [Roll Forward]

Other comprehensive (loss)/income before reclassifications

(10)

(82)

(10)

(22)

(110)

Amounts reclassified from accumulated other comprehensive income/(loss) (net of income tax)

(72)

Defined pension and post-retirement benefit costs [Member]

(8)

(10)

(82)

AOCI Attributable to Parent, Net of Tax [Roll Forward]

Other comprehensive (loss)/income before reclassifications

(1,138)

(1,152)

(713)

(241)

(26)

(483)

Amounts reclassified from accumulated other comprehensive income/(loss) (net of income tax)

(199)

(439)

AOCI Attributable to Parent, Net of Tax [Roll Forward]

(1,337)

(1,138)

(1,152)

AOCL [Member]

(1,513)

(1,884)

(1,037)

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]

$ (1,961)

$ (1,513)

$ (1,884)

[1]

Share-Based Compensation - Narrative (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) Age $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Jan. 31, 2016 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 50	$ 67	$ 123
Tax benefit from compensation expense	10	22	35
Cash received from exercise of stock options	45	61	63
Employee Services Share Based Compensation, Tax Benefit Realized From Vesting Of RSUs	$ 12	$ 19	$ 25
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted \| shares	0
Time-based stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted \| shares	0
Options, grants in period, weighted average grant date fair value (in dollars per share) \| $ / shares		$ 27.69	$ 16.88
Options, exercises in period, intrinsic value	$ 12	$ 19	$ 25
Compensation cost not yet recognized	$ 1
Time-based stock options \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost not yet recognized, period for recognition	1 year
Performance-based stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted \| shares	0
Options, exercises in period, intrinsic value	$ 8	10	9
Compensation cost not yet recognized	0
Employee Service Share-based Compensation, Tax Benefit from Exercise of Stock Options	4	$ 7	$ 6
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost not yet recognized	$ 2
Compensation cost not yet recognized, period for recognition	1 year 4 months 24 days
Vested (shares) \| shares	164,728	178,574	459,838
Vested, Weighted Average Grant Date Fair Value (in dollars per share) \| $ / shares	$ 156.14	$ 150.81	$ 120.42
Granted units \| shares	51,000
Grant date fair value,per share \| $ / shares	$ 141.19	$ 122.27
Performance-Based Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost not yet recognized	$ 12
Compensation cost not yet recognized, period for recognition	1 year 10 months 24 days
Vested (shares) \| shares	249,901	318,714	258,536
Vested, Weighted Average Grant Date Fair Value (in dollars per share) \| $ / shares	$ 154.99	$ 140.32	$ 119.75
Granted units \| shares	141,000
Grant date fair value,per share \| $ / shares	$ 91.02	$ 90.61
Phantom RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost not yet recognized	$ 18
Granted units \| shares	268,956
Grant date fair value,per share \| $ / shares	$ 83.57
Share-based compensation, expected term	3 years
Liability recognized	$ 5
2012 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant \| shares	7,000,000
Expiration period	10 years
Towers Watson & Co. 2009 Long Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 3	$ 11	$ 31
Qualified retirement age \| Age	55
Qualified years of service	15
Towers Watson & Co. 2009 Long Term Incentive Plan \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Qualified years of service in the performance period	1
Towers Watson & Co. 2009 Long Term Incentive Plan \| Restricted Stock Units (RSU) and Options \| Pre-acquisition
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of the outstanding units				$ 37
Towers Watson & Co. 2009 Long Term Incentive Plan \| Restricted Stock Units (RSU) and Options \| Post-acquisition
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of the outstanding units				$ 45

Share-Based Compensation - Assumptions (Details)	12 Months Ended
Share-Based Compensation - Assumptions (Details)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility		19.80%	21.00%
Expected dividends		1.40%	1.50%
Expected life (years)		4 years 2 months 12 days	2 years 8 months 12 days
Risk-free interest rate		1.60%	0.70%
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	17.90%	20.20%	20.30%
Expected life (years)	2 years 6 months	2 years 4 months 24 days	2 years 7 months 6 days
Risk-free interest rate	2.60%	1.40%	0.80%

Share-Based Compensation - Options Activity (Details)
$ / shares in Units, shares in Thousands, $ in Millions

12 Months Ended

Dec. 31, 2018

USD ($)

$ / shares

Time-based stock options

Balance as of beginning of period, Outstanding (in shares) | shares

754

Granted, Outstanding (in shares) | shares

Exercised, Outstanding (in shares) | shares

294

Expired, Outstanding (in shares) | shares

Balance as of end of period, Outstanding (in shares) | shares

449

Options vested or expected to vest at end of period, Outstanding (in shares) | shares

445

Options exercisable at end of period, Outstanding (in shares) | shares

329

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]

Balance as of beginning of period, Weighted Average Exercise Price (in dollars per share)

$ 103.85

^[1]

Granted, Weighted Average Exercise Price (in dollars per share)

^[1]

Exercised, Weighted Average Exercise Price (in dollars per share)

107.96

^[1]

Balance as of end of period, Weighted Average Exercise Price (in dollars per share)

101.21

^[1]

Options vested or expected to vest at end of period, Weighted Average Exercise Price (in dollars per share)

100.97

^[1]

Options exercisable at end of period, Weighted Average Exercise Price (in dollars per share)

99.48

^[1]

Expired, Weighted Average Exercise Price (in dollars per share)

102.19

^[1]

Granted, Weighted Average Exercise Price (in dollars per share)

$ 0

^[1]

End of period, Weighted Average Remaining Contractual Term

3 years

Options vested or expected to vest at end of period, Weighted Average Remaining Contractual Term

3 years

Options exercisable at end of period, Weighted Average Remaining Contractual Term

3 years

End of period, Aggregate Intrinsic Value | $

$ 23

Options vested or expected to vest at end of period, Aggregate Intrinsic Value | $

Options exercisable at end of period, Aggregate Intrinsic Value | $

$ 17

Performance-based stock options

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]

Balance as of beginning of period, Outstanding (in shares) | shares

680

Granted, Outstanding (in shares) | shares

Exercised, Outstanding (in shares) | shares

138

Balance as of end of period, Outstanding (in shares) | shares

542

Options vested or expected to vest at end of period, Outstanding (in shares) | shares

542

Options exercisable at end of period, Outstanding (in shares) | shares

542

Forfeited, Outstanding (in shares) | shares

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]

Balance as of beginning of period, Weighted Average Exercise Price (in dollars per share)

$ 106.42

^[1]

Granted, Weighted Average Exercise Price (in dollars per share)

^[1]

Exercised, Weighted Average Exercise Price (in dollars per share)

96.02

^[1]

Balance as of end of period, Weighted Average Exercise Price (in dollars per share)

110.55

^[1]

Options vested or expected to vest at end of period, Weighted Average Exercise Price (in dollars per share)

110.55

^[1]

Options exercisable at end of period, Weighted Average Exercise Price (in dollars per share)

110.55

^[1]

Forfeited, Weighted Average Exercise Price (in dollars per share)

^[1]

Granted, Weighted Average Exercise Price (in dollars per share)

$ 0

^[1]

End of period, Weighted Average Remaining Contractual Term

3 years

Options vested or expected to vest at end of period, Weighted Average Remaining Contractual Term

3 years

Options exercisable at end of period, Weighted Average Remaining Contractual Term

3 years

End of period, Aggregate Intrinsic Value | $

$ 22

Options vested or expected to vest at end of period, Aggregate Intrinsic Value | $

Options exercisable at end of period, Aggregate Intrinsic Value | $

$ 22

[1]	Certain options are exercisable in Pounds sterling and are converted to dollars using the exchange rate at December 31, 2018.

Share-Based Compensation - Nonvested Restricted Stock Units and Performance Based Stock Units Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Balance (shares)	143,000
Granted (shares)	51,000
Vested (shares)	164,728	178,574	459,838
Forfeited (shares)	10,000
Balance (shares)	19,000	143,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Balance, Weighted Average Grant Date Fair Value (in dollars per share)	$ 122.27
Granted, Weighted Average Grant Date Fair Value (in dollars per share)	153.58
Vested, Weighted Average Grant Date Fair Value (in dollars per share)	122.61
Forfeited, Weighted Average Grant Date Fair Value (in dollars per share)	117.09
Balance, Weighted Average Grant Date Fair Value (in dollars per share)	$ 141.19	$ 122.27
Performance-Based Stock Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Balance (shares)	881,000	1,200,000
Granted (shares)	141,000
Vested (shares)	249,901	318,714	258,536
Forfeited (shares)	14,000
Balance (shares)	758,000	881,000	1,200,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Balance, Weighted Average Grant Date Fair Value (in dollars per share)	$ 90.61
Granted, Weighted Average Grant Date Fair Value (in dollars per share)	204.13
Vested, Weighted Average Grant Date Fair Value (in dollars per share)	125.75
Forfeited, Weighted Average Grant Date Fair Value (in dollars per share)	118.94
Balance, Weighted Average Grant Date Fair Value (in dollars per share)	$ 91.02	$ 90.61

Earnings Per Share - Narrative (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive securities excluded from computation of earnings per share	0	0	500
Restricted share units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Antidilutive securities excluded from computation of earnings per share	200	0	0
Time-based award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	400	800	1,200
Restricted share units outstanding		100	400
Phantom Share Units (PSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted share units outstanding	300	0	0
Performance-Based Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	500	700	900
Restricted share units outstanding	758	881	1,200

Earnings Per Share - Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Net income attributable to Willis Towers Watson	$ 378	$ 44	$ 58	$ 215	$ 245	$ (54)	$ 33	$ 344	$ 695	$ 568	$ 420
Basic weighted-average number of shares outstanding									131	135	137
Dilutive effect of potentially issuable shares									1	1	1
Diluted weighted-average number of shares outstanding									132	136	138
Basic earnings per share	$ 2.91	$ 0.34	$ 0.44	$ 1.62	$ 1.85	$ (0.40)	$ 0.24	$ 2.51	$ 5.29	$ 4.21	$ 3.07
Dilutive effect of potentially issuable shares									(0.02)	(0.03)	(0.03)
Diluted earnings per share	$ 2.89	$ 0.33	$ 0.44	$ 1.61	$ 1.84	$ (0.40)	$ 0.24	$ 2.50	$ 5.27	$ 4.18	$ 3.04

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

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+ Details

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

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+ Details

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Supplemental Disclosures of Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental disclosures of cash flow information:
Cash payments for income taxes, net	$ 178	$ 203	$ 158
Cash payments for interest	176	169	143
Cash acquired	13	0	476
Supplemental disclosures of non-cash investing and financing activities:
Issuance of shares and assumed awards in connection with the Merger		0	8,723
Fair value of deferred and contingent consideration related to acquisitions	$ 36	$ 0	$ 0

Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Data [Abstract]
Revenue	$ 2,372	$ 1,859	$ 1,990	$ 2,292	$ 2,078	$ 1,852	$ 1,953	$ 2,319	$ 8,513	$ 8,202	$ 7,887
Total costs of providing services	1,902	1,842	1,927	2,033	1,998	1,878	1,892	1,918	7,704	7,686	7,539
Income from operations	470	17	63	259	80	(26)	61	401	809	516	348
Net income/(loss)	383	46	65	221	253	(54)	41	352	715	592	438
Net income/(loss) attributable to Willis Towers Watson	$ 378	$ 44	$ 58	$ 215	$ 245	$ (54)	$ 33	$ 344	$ 695	$ 568	$ 420
Earnings/(loss) per share
Basic earnings per share	$ 2.91	$ 0.34	$ 0.44	$ 1.62	$ 1.85	$ (0.40)	$ 0.24	$ 2.51	$ 5.29	$ 4.21	$ 3.07
Diluted earnings per share	$ 2.89	$ 0.33	$ 0.44	$ 1.61	$ 1.84	$ (0.40)	$ 0.24	$ 2.50	$ 5.27	$ 4.18	$ 3.04

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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+ Details

Financial Information for Issuers and Other Guarantor Subsidiaries - Narrative (Details)
€ in Millions

Dec. 31, 2018

USD ($)

Sep. 10, 2018

USD ($)

May 16, 2017

USD ($)

Mar. 07, 2017

USD ($)

May 26, 2016

USD ($)

May 26, 2016

EUR (€)

Mar. 22, 2016

USD ($)

Mar. 15, 2016

USD ($)

Aug. 15, 2013

USD ($)

Sep. 29, 2009

USD ($)

Revolving Credit Facility [Member] | Revolving 1.25 Billion Dollar Credit Facility [Member]

$ 6,400,000,000

Trinity Acquisition plc [Member] | Revolving Credit Facility [Member]

^[1]

1,250,000,000

Trinity Acquisition plc [Member] | Revolving Credit Facility [Member] | Revolving 1.25 Billion Dollar Credit Facility [Member]

$ 1,250,000,000

130,000,000

Senior Notes [Member]

Senior Notes [Member] | Willis North America [Member]

4,479,000,000

Senior Notes [Member] | Trinity Acquisition plc [Member]

1,800,000,000

$ 1,000,000,000

$ 650,000,000

$ 187,000,000

Parent Company [Member] | Senior Notes [Member]

$ 2,100,000,000

$ 609,000,000

€ 540

$ 1,000,000,000

$ 525,000,000

$ 500,000,000

[1]	Notes issued in Euro (€540 million)

Financial Information for Issuers and Other Guarantor Subsidiaries - Condensed Consolidating Statement of Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Revenue	$ 2,372	$ 1,859	$ 1,990	$ 2,292	$ 2,078	$ 1,852	$ 1,953	$ 2,319	$ 8,513	$ 8,202	$ 7,887
Costs of providing services
Salaries and benefits									5,123	4,967	4,849
Other operating expenses									1,637	1,534	1,551
Depreciation									208	203	178
Amortization									534	581	591
Restructuring costs									0	132	193
Transaction and integration expenses									202	269	177
Total costs of providing services	1,902	1,842	1,927	2,033	1,998	1,878	1,892	1,918	7,704	7,686	7,539
Income from operations	470	17	63	259	80	(26)	61	401	809	516	348
Intercompany income/(expense)									0	0	0
Interest expense									(208)	(188)	(184)
Other income, net									250	164	178
INCOME FROM OPERATIONS BEFORE INCOME TAXES									851	492	342
(Provision for)/benefit from income taxes									(136)	100	96
Equity account for subsidiaries									0	0	0
NET INCOME	383	46	65	221	253	(54)	41	352	715	592	438
Income attributable to non-controlling interests									(20)	(24)	(18)
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON	$ 378	$ 44	$ 58	$ 215	$ 245	$ (54)	$ 33	$ 344	695	568	420
Comprehensive income/(loss) before non- controlling interests									267	976	(429)
Comprehensive (income)/loss attributable to non-controlling interests									(20)	(37)	2
Comprehensive income/(loss) attributable to Willis Towers Watson									247	939	(427)
Other guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue									0	0	2
Costs of providing services
Salaries and benefits									0	0	1
Other operating expenses									165	91	112
Depreciation									4	6	5
Amortization									3	3	0
Restructuring costs										8	29
Transaction and integration expenses									1	73	16
Total costs of providing services									173	181	163
Income from operations									(173)	(181)	(161)
Intercompany income/(expense)									356	350	320
Interest expense									0	0	0
Other income, net									2	0	2
INCOME FROM OPERATIONS BEFORE INCOME TAXES									185	169	161
(Provision for)/benefit from income taxes									41	53	39
Equity account for subsidiaries									498	370	247
NET INCOME									724	592	447
Income attributable to non-controlling interests									0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									724	592	447
Comprehensive income/(loss) before non- controlling interests									286	952	(381)
Comprehensive (income)/loss attributable to non-controlling interests									0	0	0
Comprehensive income/(loss) attributable to Willis Towers Watson									286	952	(381)
Non-guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue									8,479	8,183	7,866
Costs of providing services
Salaries and benefits									5,053	4,915	4,831
Other operating expenses									1,430	1,419	1,348
Depreciation									204	197	159
Amortization									534	581	591
Restructuring costs										109	125
Transaction and integration expenses									193	177	134
Total costs of providing services									7,414	7,398	7,188
Income from operations									1,065	785	678
Intercompany income/(expense)									(536)	(507)	(535)
Interest expense									(16)	(20)	(23)
Other income, net									1,540	367	176
INCOME FROM OPERATIONS BEFORE INCOME TAXES									2,053	625	296
(Provision for)/benefit from income taxes									(173)	78	(26)
Equity account for subsidiaries									0	0	0
NET INCOME									1,880	703	270
Income attributable to non-controlling interests									(20)	(24)	(18)
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									1,860	679	252
Comprehensive income/(loss) before non- controlling interests									1,470	1,051	(549)
Comprehensive (income)/loss attributable to non-controlling interests									(20)	(37)	2
Comprehensive income/(loss) attributable to Willis Towers Watson									1,450	1,014	(547)
Reportable Legal Entities [Member] \| Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue									0	0	0
Costs of providing services
Salaries and benefits									2	4	2
Other operating expenses									3	3	3
Depreciation									0	0	0
Amortization									0	0	0
Restructuring costs										0	0
Transaction and integration expenses									0	0	1
Total costs of providing services									5	7	6
Income from operations									(5)	(7)	(6)
Intercompany income/(expense)									0	0	0
Interest expense									(30)	(30)	(32)
Other income, net									0	35	0
INCOME FROM OPERATIONS BEFORE INCOME TAXES									(35)	(2)	(38)
(Provision for)/benefit from income taxes									0	0	0
Equity account for subsidiaries									730	570	458
NET INCOME									695	568	420
Income attributable to non-controlling interests									0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									695	568	420
Comprehensive income/(loss) before non- controlling interests									247	939	(427)
Comprehensive (income)/loss attributable to non-controlling interests									0	0	0
Comprehensive income/(loss) attributable to Willis Towers Watson									247	939	(427)
Consolidating adjustments [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue									0	0	0
Costs of providing services
Salaries and benefits									0	0	0
Other operating expenses									0	0	0
Depreciation									0	0	0
Amortization									(3)	(3)	0
Restructuring costs										0	0
Transaction and integration expenses									0	0	0
Total costs of providing services									(3)	(3)	0
Income from operations									3	3	0
Intercompany income/(expense)									0	0	0
Interest expense									0	0	0
Other income, net									(1,292)	(238)	0
INCOME FROM OPERATIONS BEFORE INCOME TAXES									(1,289)	(235)	0
(Provision for)/benefit from income taxes									0	0	0
Equity account for subsidiaries									(1,789)	(1,401)	(1,013)
NET INCOME									(3,078)	(1,636)	(1,013)
Income attributable to non-controlling interests									0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									(3,078)	(1,636)	(1,013)
Comprehensive income/(loss) before non- controlling interests									(1,662)	(2,826)	1,850
Comprehensive (income)/loss attributable to non-controlling interests									0	0	0
Comprehensive income/(loss) attributable to Willis Towers Watson									(1,662)	(2,826)	1,850
Willis North America [Member] \| Reportable Legal Entities [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue									34	19	19
Costs of providing services
Salaries and benefits									68	48	15
Other operating expenses									38	20	88
Depreciation									0	0	14
Amortization									0	0	0
Restructuring costs										15	39
Transaction and integration expenses									8	19	26
Total costs of providing services									114	102	182
Income from operations									(80)	(83)	(163)
Intercompany income/(expense)									56	34	109
Interest expense									(58)	(35)	(39)
Other income, net									0	0	0
INCOME FROM OPERATIONS BEFORE INCOME TAXES									(82)	(84)	(93)
(Provision for)/benefit from income taxes									(1)	(29)	86
Equity account for subsidiaries									124	171	157
NET INCOME									41	58	150
Income attributable to non-controlling interests									0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									41	58	150
Comprehensive income/(loss) before non- controlling interests									(88)	197	(266)
Comprehensive (income)/loss attributable to non-controlling interests									0	0	0
Comprehensive income/(loss) attributable to Willis Towers Watson									(88)	197	(266)
Trinity Acquisition plc [Member] \| Reportable Legal Entities [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue									0	0	0
Costs of providing services
Salaries and benefits									0	0	0
Other operating expenses									1	1	0
Depreciation									0	0	0
Amortization									0	0	0
Restructuring costs										0	0
Transaction and integration expenses									0	0	0
Total costs of providing services									1	1	0
Income from operations									(1)	(1)	0
Intercompany income/(expense)									124	123	106
Interest expense									(104)	(103)	(90)
Other income, net									0	0	0
INCOME FROM OPERATIONS BEFORE INCOME TAXES									19	19	16
(Provision for)/benefit from income taxes									(3)	(2)	(3)
Equity account for subsidiaries									437	290	151
NET INCOME									453	307	164
Income attributable to non-controlling interests									0	0	0
NET INCOME ATTRIBUTABLE TO WILLIS TOWERS WATSON									453	307	164
Comprehensive income/(loss) before non- controlling interests									14	663	(656)
Comprehensive (income)/loss attributable to non-controlling interests									0	0	0
Comprehensive income/(loss) attributable to Willis Towers Watson									$ 14	$ 663	$ (656)

Financial Information for Issuers and Other Guarantor Subsidiaries - Condensed Consolidating Balance Sheet (Details) - USD ($)
$ in Millions

Dec. 31, 2018

Jan. 01, 2018

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

ASSETS

$ 1,033

$ 1,030

$ 870

$ 532

12,604

12,155

2,379

$ 2,555

2,246

404

430

16,420

15,861

942

985

10,465

10,519

10,413

3,318

3,882

773

764

467

447

15,965

16,597

32,385

32,458

12,604

12,155

Short-term debt and current portion of long-term debt

1,647

1,711

186

864

804

15,301

14,755

4,389

4,450

1,170

1,259

559

615

540

558

429

544

7,087

7,426

22,388

22,181

EQUITY

^[1]

9,852

10,126

^[1]

119

123

9,971

^[1]

10,249

^[1]

10,183

2,360

Other guarantors [Member]

^[1]

32,385

32,458

ASSETS

123

116

8,108

8,425

8,264

8,586

Short-term debt and current portion of long-term debt

4,691

3,895

4,696

3,900

4,712

3,934

EQUITY

3,552

4,652

3,552

4,652

8,264

8,586

Non-guarantors [Member]

ASSETS

1,033

1,027

870

527

12,604

12,155

2,355

2,242

357

264

16,349

15,688

926

960

10,465

10,519

3,318

3,882

773

764

452

388

15,934

16,513

32,283

32,201

12,604

12,155

Short-term debt and current portion of long-term debt

1,641

1,685

935

724

15,180

14,649

517

4,021

1,170

1,259

688

704

420

438

411

520

3,206

7,026

18,386

21,675

EQUITY

13,752

10,375

119

123

13,871

10,498

Reportable Legal Entities [Member] | Parent Company [Member]

32,283

32,201

ASSETS

4,755

6,202

4,755

6,202

5,691

4,506

10,446

10,710

Short-term debt and current portion of long-term debt

498

497

498

497

594

584

EQUITY

9,852

10,126

9,852

10,126

Consolidating adjustments [Member]

10,446

10,710

ASSETS

(298)

(146)

(298)

(146)

(6,110)

(8,703)

(58)

(60)

(128)

(90)

(6,296)

(8,853)

(23,125)

(20,974)

(29,719)

(29,973)

Short-term debt and current portion of long-term debt

(250)

(150)

(250)

(150)

(6,110)

(8,703)

(129)

(89)

(6,239)

(8,792)

(6,489)

(8,942)

EQUITY

(23,230)

(21,031)

(23,230)

(21,031)

Willis North America [Member] | Reportable Legal Entities [Member]

(29,719)

(29,973)

ASSETS

311

267

335

271

115

115

6,649

6,125

7,076

6,511

Short-term debt and current portion of long-term debt

186

226

102

902

787

1,635

986

120

2,670

1,912

2,896

2,014

EQUITY

4,180

4,497

4,180

4,497

Trinity Acquisition plc [Member] | Reportable Legal Entities [Member]

7,076

6,511

ASSETS

$ 0

1,355

2,501

1,357

2,504

2,677

1,918

4,035

4,423

Short-term debt and current portion of long-term debt

2,256

2,883

2,256

2,883

2,289

2,916

EQUITY

1,746

1,507

1,746

1,507