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v3.25.3

Revenue from Contracts with Customers - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | $ 3,997 | $ 3,721 | $ 12,881 | $ 11,551
U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 2,084 | 2,083 | 6,126 | 5,432
Americas other than U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 381 | 263 | 1,150 | 948
U.K. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 525 | 437 | 1,756 | 1,568
Ireland |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 42 | 38 | 133 | 106
Europe, Middle East, & Africa other than U.K. and Ireland |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 555 | 492 | 2,451 | 2,267
Asia Pacific |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 410 | 408 | 1,265 | 1,230
Operating Segments | Risk Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 2,525 | 2,355 | 8,582 | 7,980
Operating Segments | Human Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 1,475 | 1,369 | 4,311 | 3,597
Operating Segments | U.S. | Risk Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 1,229 | 1,206 | 3,774 | 3,501
Operating Segments | U.S. | Human Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 858 | 880 | 2,364 | 1,957
Operating Segments | Americas other than U.S. | Risk Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 260 | 195 | 799 | 682
Operating Segments | Americas other than U.S. | Human Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 121 | 68 | 351 | 266
Operating Segments | U.K. | Risk Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 303 | 255 | 1,144 | 1,045
Operating Segments | U.K. | Human Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 222 | 182 | 612 | 523
Operating Segments | Ireland | Risk Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 21 | 20 | 67 | 56
Operating Segments | Ireland | Human Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 21 | 18 | 66 | 50
Operating Segments | Europe, Middle East, & Africa other than U.K. and Ireland | Risk Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 400 | 361 | 1,815 | 1,717
Operating Segments | Europe, Middle East, & Africa other than U.K. and Ireland | Human Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 155 | 131 | 636 | 550
Operating Segments | Asia Pacific | Risk Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 312 | 318 | 983 | 979
Operating Segments | Asia Pacific | Human Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 98 | 90 | 282 | 251
Eliminations |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | (3) | (3) | (12) | (26)
Eliminations | Risk Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 1 | 1 | 5 | 16
Eliminations | Human Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 3 | 3 | 7 | 10
Corporate/Eliminations |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | (3) | (3) | (12) | (26)
Corporate/Eliminations | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | (3) | (3) | (12) | (26)
Corporate/Eliminations | Americas other than U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 0 | 0 | 0 | 0
Corporate/Eliminations | U.K. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 0 | 0 | 0 | 0
Corporate/Eliminations | Ireland |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 0 | 0 | 0 | 0
Corporate/Eliminations | Europe, Middle East, & Africa other than U.K. and Ireland |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 0 | 0 | 0 | 0
Corporate/Eliminations | Asia Pacific |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 0 | 0 | 0 | 0
Commercial Risk Solutions | Operating Segments | Risk Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 1,988 | 1,852 | 6,168 | 5,675
Reinsurance Solutions | Operating Segments | Risk Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 537 | 503 | 2,414 | 2,305
Health Solutions | Operating Segments | Human Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | 935 | 870 | 2,733 | 2,265
Wealth Solutions | Operating Segments | Human Capital |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Total revenue | $ 540 | $ 499 | $ 1,578 | $ 1,332

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