v3.26.1
Fair Value of Financial Instruments - Schedule of Assets by Class of Instrument that are Measured at Fair Value on Recurring Basis (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities $ 45,264 $ 45,762
Equity securities 564 555
Limited partnerships 2,863 2,784
Other invested assets:    
Derivative assets 36 39
Short-term investments 79 37
Total other invested assets 115 76
Separate account assets 4,396 4,369
Total assets 53,202 53,546
Interest rate swaps    
Other invested assets:    
Derivative assets 8 11
Foreign currency swaps    
Other invested assets:    
Derivative assets 6 4
Equity index options    
Other invested assets:    
Derivative assets 15 18
Forward bond purchase commitments    
Other invested assets:    
Derivative assets 7 6
U.S. government, agencies and government-sponsored enterprises    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 3,624 3,701
State and political subdivisions    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,999 2,114
Non-U.S. government    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,333 1,215
U.S. corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 26,355 27,046
U.S. corporate | Utilities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 4,551 4,515
U.S. corporate | Energy    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 2,421 2,452
U.S. corporate | Finance and insurance    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 6,871 7,057
U.S. corporate | Consumer—non-cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 4,390 4,406
U.S. corporate | Technology and communications    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 2,480 2,749
U.S. corporate | Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 867 954
U.S. corporate | Capital goods    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 2,279 2,319
U.S. corporate | Consumer—cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,207 1,249
U.S. corporate | Transportation    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,052 1,075
U.S. corporate | Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 237 270
Non-U.S. corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 7,018 7,191
Non-U.S. corporate | Utilities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 585 637
Non-U.S. corporate | Energy    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 918 944
Non-U.S. corporate | Finance and insurance    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,689 1,719
Non-U.S. corporate | Consumer—non-cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 531 557
Non-U.S. corporate | Technology and communications    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 721 689
Non-U.S. corporate | Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 735 761
Non-U.S. corporate | Capital goods    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 700 692
Non-U.S. corporate | Consumer—cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 217 250
Non-U.S. corporate | Transportation    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 490 485
Non-U.S. corporate | Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 432 457
Residential mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,069 1,100
Commercial mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,361 1,309
Other asset-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 2,505 2,086
Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Equity securities 525 485
Limited partnerships 0 0
Other invested assets:    
Derivative assets 0 0
Short-term investments 0 0
Total other invested assets 0 0
Separate account assets 4,396 4,369
Total assets 4,921 4,854
Level 1 | Interest rate swaps    
Other invested assets:    
Derivative assets 0 0
Level 1 | Foreign currency swaps    
Other invested assets:    
Derivative assets 0 0
Level 1 | Equity index options    
Other invested assets:    
Derivative assets 0 0
Level 1 | Forward bond purchase commitments    
Other invested assets:    
Derivative assets 0 0
Level 1 | U.S. government, agencies and government-sponsored enterprises    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | State and political subdivisions    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | Non-U.S. government    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | U.S. corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | U.S. corporate | Utilities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | U.S. corporate | Energy    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | U.S. corporate | Finance and insurance    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | U.S. corporate | Consumer—non-cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | U.S. corporate | Technology and communications    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | U.S. corporate | Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | U.S. corporate | Capital goods    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | U.S. corporate | Consumer—cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | U.S. corporate | Transportation    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | U.S. corporate | Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | Non-U.S. corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | Non-U.S. corporate | Utilities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | Non-U.S. corporate | Energy    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | Non-U.S. corporate | Finance and insurance    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | Non-U.S. corporate | Consumer—non-cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | Non-U.S. corporate | Technology and communications    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | Non-U.S. corporate | Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | Non-U.S. corporate | Capital goods    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | Non-U.S. corporate | Consumer—cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | Non-U.S. corporate | Transportation    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | Non-U.S. corporate | Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | Residential mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | Commercial mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 1 | Other asset-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 42,021 42,691
Equity securities 29 29
Limited partnerships 0 0
Other invested assets:    
Derivative assets 14 15
Short-term investments 56 14
Total other invested assets 70 29
Separate account assets 0 0
Total assets 42,120 42,749
Level 2 | Interest rate swaps    
Other invested assets:    
Derivative assets 8 11
Level 2 | Foreign currency swaps    
Other invested assets:    
Derivative assets 6 4
Level 2 | Equity index options    
Other invested assets:    
Derivative assets 0 0
Level 2 | Forward bond purchase commitments    
Other invested assets:    
Derivative assets 0 0
Level 2 | U.S. government, agencies and government-sponsored enterprises    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 3,624 3,701
Level 2 | State and political subdivisions    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,999 2,114
Level 2 | Non-U.S. government    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,318 1,199
Level 2 | U.S. corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 24,360 25,089
Level 2 | U.S. corporate | Utilities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 3,503 3,511
Level 2 | U.S. corporate | Energy    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 2,357 2,431
Level 2 | U.S. corporate | Finance and insurance    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 6,261 6,438
Level 2 | U.S. corporate | Consumer—non-cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 4,356 4,371
Level 2 | U.S. corporate | Technology and communications    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 2,461 2,731
Level 2 | U.S. corporate | Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 850 938
Level 2 | U.S. corporate | Capital goods    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 2,243 2,282
Level 2 | U.S. corporate | Consumer—cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,166 1,194
Level 2 | U.S. corporate | Transportation    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,040 1,048
Level 2 | U.S. corporate | Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 123 145
Level 2 | Non-U.S. corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 6,269 6,442
Level 2 | Non-U.S. corporate | Utilities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 370 400
Level 2 | Non-U.S. corporate | Energy    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 819 837
Level 2 | Non-U.S. corporate | Finance and insurance    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,667 1,697
Level 2 | Non-U.S. corporate | Consumer—non-cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 514 541
Level 2 | Non-U.S. corporate | Technology and communications    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 701 680
Level 2 | Non-U.S. corporate | Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 621 645
Level 2 | Non-U.S. corporate | Capital goods    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 621 628
Level 2 | Non-U.S. corporate | Consumer—cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 191 226
Level 2 | Non-U.S. corporate | Transportation    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 402 406
Level 2 | Non-U.S. corporate | Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 363 382
Level 2 | Residential mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,062 1,097
Level 2 | Commercial mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,341 1,290
Level 2 | Other asset-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 2,048 1,759
Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 3,243 3,071
Equity securities 10 41
Limited partnerships 19 16
Other invested assets:    
Derivative assets 22 24
Short-term investments 23 23
Total other invested assets 45 47
Separate account assets 0 0
Total assets 3,317 3,175
Level 3 | Interest rate swaps    
Other invested assets:    
Derivative assets 0 0
Level 3 | Foreign currency swaps    
Other invested assets:    
Derivative assets 0 0
Level 3 | Equity index options    
Other invested assets:    
Derivative assets 15 18
Level 3 | Forward bond purchase commitments    
Other invested assets:    
Derivative assets 7 6
Level 3 | U.S. government, agencies and government-sponsored enterprises    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 3 | State and political subdivisions    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Level 3 | Non-U.S. government    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 15 16
Level 3 | U.S. corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,995 1,957
Level 3 | U.S. corporate | Utilities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,048 1,004
Level 3 | U.S. corporate | Energy    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 64 21
Level 3 | U.S. corporate | Finance and insurance    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 610 619
Level 3 | U.S. corporate | Consumer—non-cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 34 35
Level 3 | U.S. corporate | Technology and communications    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 19 18
Level 3 | U.S. corporate | Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 17 16
Level 3 | U.S. corporate | Capital goods    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 36 37
Level 3 | U.S. corporate | Consumer—cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 41 55
Level 3 | U.S. corporate | Transportation    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 12 27
Level 3 | U.S. corporate | Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 114 125
Level 3 | Non-U.S. corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 749 749
Level 3 | Non-U.S. corporate | Utilities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 215 237
Level 3 | Non-U.S. corporate | Energy    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 99 107
Level 3 | Non-U.S. corporate | Finance and insurance    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 22 22
Level 3 | Non-U.S. corporate | Consumer—non-cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 17 16
Level 3 | Non-U.S. corporate | Technology and communications    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 20 9
Level 3 | Non-U.S. corporate | Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 114 116
Level 3 | Non-U.S. corporate | Capital goods    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 79 64
Level 3 | Non-U.S. corporate | Consumer—cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 26 24
Level 3 | Non-U.S. corporate | Transportation    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 88 79
Level 3 | Non-U.S. corporate | Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 69 75
Level 3 | Residential mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 7 3
Level 3 | Commercial mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 20 19
Level 3 | Other asset-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 457 327
Total limited partnerships accounted for at NAV    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Limited partnerships 2,844 2,768
Other invested assets:    
Total assets $ 2,844 $ 2,768