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
Mar. 31, 2026
Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities $ 45,095 $ 45,762
Equity securities 544 555
Limited partnerships 2,843 2,784
Other invested assets:    
Derivative assets 32 39
Short-term investments 29 37
Total other invested assets 61 76
Separate account assets 4,093 4,369
Total assets 52,636 53,546
Interest rate swaps    
Other invested assets:    
Derivative assets 8 11
Foreign currency swaps    
Other invested assets:    
Derivative assets 8 4
Equity index options    
Other invested assets:    
Derivative assets 12 18
Forward bond purchase commitments    
Other invested assets:    
Derivative assets 4 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 3,616 3,701
State and political subdivisions    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 2,086 2,114
Non-U.S. government    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,191 1,215
U.S. corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 26,509 27,046
U.S. corporate | Utilities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 4,483 4,515
U.S. corporate | Energy    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 2,425 2,452
U.S. corporate | Finance and insurance    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 6,922 7,057
U.S. corporate | Consumer—non-cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 4,354 4,406
U.S. corporate | Technology and communications    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 2,620 2,749
U.S. corporate | Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 895 954
U.S. corporate | Capital goods    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 2,273 2,319
U.S. corporate | Consumer—cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,219 1,249
U.S. corporate | Transportation    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,057 1,075
U.S. corporate | Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 261 270
Non-U.S. corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 7,045 7,191
Non-U.S. corporate | Utilities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 599 637
Non-U.S. corporate | Energy    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 915 944
Non-U.S. corporate | Finance and insurance    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,700 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 550 557
Non-U.S. corporate | Technology and communications    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 706 689
Non-U.S. corporate | Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 741 761
Non-U.S. corporate | Capital goods    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 686 692
Non-U.S. corporate | Consumer—cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 221 250
Non-U.S. corporate | Transportation    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 491 485
Non-U.S. corporate | Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 436 457
Residential mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,064 1,100
Commercial mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,358 1,309
Other asset-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 2,226 2,086
Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 0 0
Equity securities 467 485
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 4,093 4,369
Total assets 4,560 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 42,072 42,691
Equity securities 29 29
Limited partnerships 0 0
Other invested assets:    
Derivative assets 16 15
Short-term investments 6 14
Total other invested assets 22 29
Separate account assets 0 0
Total assets 42,123 42,749
Level 2 | Interest rate swaps    
Other invested assets:    
Derivative assets 8 11
Level 2 | Foreign currency swaps    
Other invested assets:    
Derivative assets 8 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 3,616 3,701
Level 2 | State and political subdivisions    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 2,086 2,114
Level 2 | Non-U.S. government    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,176 1,199
Level 2 | U.S. corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 24,621 25,089
Level 2 | U.S. corporate | Utilities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 3,490 3,511
Level 2 | U.S. corporate | Energy    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 2,404 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 6,318 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 4,320 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 2,610 2,731
Level 2 | U.S. corporate | Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 878 938
Level 2 | U.S. corporate | Capital goods    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 2,237 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 1,177 1,194
Level 2 | U.S. corporate | Transportation    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,044 1,048
Level 2 | U.S. corporate | Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 143 145
Level 2 | Non-U.S. corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 6,308 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 372 400
Level 2 | Non-U.S. corporate | Energy    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 807 837
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 1,678 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 533 541
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 697 680
Level 2 | Non-U.S. corporate | Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 627 645
Level 2 | Non-U.S. corporate | Capital goods    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 623 628
Level 2 | Non-U.S. corporate | Consumer—cyclical    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 196 226
Level 2 | Non-U.S. corporate | Transportation    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 413 406
Level 2 | Non-U.S. corporate | Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 362 382
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 1,338 1,290
Level 2 | Other asset-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 1,865 1,759
Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 3,023 3,071
Equity securities 48 41
Limited partnerships 20 16
Other invested assets:    
Derivative assets 16 24
Short-term investments 23 23
Total other invested assets 39 47
Separate account assets 0 0
Total assets 3,130 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 12 18
Level 3 | Forward bond purchase commitments    
Other invested assets:    
Derivative assets 4 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 1,888 1,957
Level 3 | U.S. corporate | Utilities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 993 1,004
Level 3 | U.S. corporate | Energy    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 21 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 604 619
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 10 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 42 55
Level 3 | U.S. corporate | Transportation    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 13 27
Level 3 | U.S. corporate | Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 118 125
Level 3 | Non-U.S. corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 737 749
Level 3 | Non-U.S. corporate | Utilities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 227 237
Level 3 | Non-U.S. corporate | Energy    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 108 107
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 9 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 63 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 25 24
Level 3 | Non-U.S. corporate | Transportation    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 78 79
Level 3 | Non-U.S. corporate | Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 74 75
Level 3 | Residential mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities 2 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 361 327
Total limited partnerships accounted for at NAV    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Limited partnerships 2,823 2,768
Other invested assets:    
Total assets $ 2,823 $ 2,768