XML 128 R105.htm IDEA: XBRL DOCUMENT v3.25.0.1
Segment Information (Segments and Geographic Areas) (Details) - USD ($)
$ in Millions
 1 Months Ended 12 Months Ended
Oct. 31, 2023
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Segment Reporting, Asset Reconciling Item [Line Items]        
Revenue   $ 24,458 $ 22,736 $ 20,720
Compensation and benefits   13,996 13,099 12,071
Depreciation and amortization expense   369 370 381
Identified intangible amortization expense   377 343 338
Other operating expenses   3,899 3,642 3,650
Operating income   5,817 5,282 4,280
Risk and Insurance Services        
Segment Reporting, Asset Reconciling Item [Line Items]        
Fiduciary interest income   497 453 120
Risk and Insurance Services | Guy Carpenter Reinsurance Group        
Segment Reporting, Asset Reconciling Item [Line Items]        
Gain from the settlement $ 58   58  
Operating Segments        
Segment Reporting, Asset Reconciling Item [Line Items]        
Revenue   24,528 22,798 20,784
Compensation and benefits   13,857 12,951 11,928
Depreciation and amortization expense   306 296 289
Identified intangible amortization expense   377 343 338
Other operating expenses   3,853 3,597 3,587
Operating income   6,135 5,611 4,642
Operating Segments | Risk and Insurance Services        
Segment Reporting, Asset Reconciling Item [Line Items]        
Revenue   15,395 14,089 12,645
Compensation and benefits   8,499 7,702 7,101
Depreciation and amortization expense   192 190 178
Identified intangible amortization expense   326 297 291
Other operating expenses   2,013 1,955 1,986
Operating income   4,365 3,945 3,089
Fiduciary interest income   497 453 120
Gain related to investments in private equity funds and other investments   22 18 12
Operating Segments | Risk and Insurance Services | Guy Carpenter Reinsurance Group        
Segment Reporting, Asset Reconciling Item [Line Items]        
Revenue   2,544 2,432 2,060
Operating Segments | Consulting Segment        
Segment Reporting, Asset Reconciling Item [Line Items]        
Revenue   9,133 8,709 8,139
Compensation and benefits   5,358 5,249 4,827
Depreciation and amortization expense   114 106 111
Identified intangible amortization expense   51 46 47
Other operating expenses   1,840 1,642 1,601
Operating income   1,770 1,666 1,553
Operating Segments | Consulting Segment | Mercer U.S. Affinity Business        
Segment Reporting, Asset Reconciling Item [Line Items]        
Pre-tax gain (loss) on sale   (35)   112
Operating Segments | Consulting Segment | Small Individual Financial Advisory Business        
Segment Reporting, Asset Reconciling Item [Line Items]        
Pre-tax gain (loss) on sale   35 17  
Corporate/Eliminations        
Segment Reporting, Asset Reconciling Item [Line Items]        
Revenue   (70) (62) (64)
Compensation and benefits   139 148 143
Depreciation and amortization expense   63 74 92
Identified intangible amortization expense   0 0 0
Other operating expenses   46 45 63
Operating income   (318) (329) (362)
Inter-segment | Consulting Segment        
Segment Reporting, Asset Reconciling Item [Line Items]        
Revenue   $ 60 $ 56 $ 59