v2.4.0.8
Document and Entity Information
12 Months Ended
Dec. 31, 2014
Document and Entity Information [Abstract]  
Entity Registrant Name WILLIS GROUP HOLDINGS PLC
Entity Central Index Key 0001140536
Document Type 8-K
Document Period End Date Aug. 04, 2015
Amendment Flag false
Document Fiscal Year Focus 2014
Current Fiscal Year End Date --12-31