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v3.22.0.1

Segment Information (Details For MMC's Operating Segments) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Segment Reporting Information [Line Items] |  |  |
Revenue | $ 19,820 | $ 17,224 | $ 16,652
Operating Income (Loss) | 4,312 | 3,066 | 2,677
Total Assets | 34,388 | 33,049 | 31,357
Depreciation and Amortization | 747 | 741 | 647
Capital Expenditures | 406 | 348 | 421
Equity method income |  |  | 12
Equity method investments | 207 | 280 |
Risk and Insurance Services |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenue | 12,085 | 10,337 | 9,599
Interest income, fiduciary assets | 15 | 46 | 105
Consulting |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenue | 7,789 | 6,976 | 7,143
Operating Segments |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenue | 19,874 | 17,313 | 16,742
Operating Income (Loss) | 4,584 | 3,340 | 3,043
Total Assets | 32,342 | 30,183 | 35,820
Depreciation and Amortization | 676 | 674 | 572
Capital Expenditures | 323 | 277 | 334
Operating Segments | Risk and Insurance Services |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenue | 12,085 | 10,337 | 9,599
Operating Income (Loss) | 3,080 | 2,346 | 1,833
Total Assets | 21,996 | 20,612 | 26,098
Depreciation and Amortization | 505 | 500 | 416
Capital Expenditures | 214 | 170 | 184
Interest income, fiduciary assets | 15 | 46 | 105
Equity method income | 31 | 27 | 25
Gain (loss) on consolidation of business | 267 |  |
Pre-tax gain on sale | 50 |  |
Equity method investments | 53 | 165 | 179
Operating Segments | Consulting |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenue | 7,789 | 6,976 | 7,143
Operating Income (Loss) | 1,504 | 994 | 1,210
Total Assets | 10,346 | 9,571 | 9,722
Depreciation and Amortization | 171 | 174 | 156
Capital Expenditures | 109 | 107 | 150
Equity method income |  | 5 | 16
Equity method investments | 5 | 5 | 149
Corporate/Eliminations |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenue | (54) | (89) | (90)
Operating Income (Loss) | (272) | (274) | (366)
Total Assets | 2,046 | 2,866 | (4,463)
Depreciation and Amortization | 71 | 67 | 75
Capital Expenditures | 83 | 71 | 87
Inter-segment | Risk and Insurance Services |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenue | 5 | 5 | 8
Inter-segment | Consulting |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenue | $ 49 | $ 84 | $ 82

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