v3.26.1
Fair Value Measurements - Fair Value Measurement (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivatives $ 151 $ 154
Assets held in separate accounts 116,066 109,772
Total assets 152,828 147,429
Derivatives 204 232
Total liabilities 150,642 145,004
Fixed maturities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 22,519 22,838
U.S. Treasuries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 527 470
US Government Agencies Debt Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 28 28
State, municipalities and political subdivisions    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 318 359
Debt Security, Corporate, US    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 6,213 6,012
Private Equity Funds, US    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 4,422 4,473
Foreign corporate public securities and foreign governments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 2,161 2,157
Private Equity Funds, Non-US    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 2,178 2,248
Residential mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 3,102 3,237
Commercial mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 1,649 1,879
Other asset-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 1,921 1,975
Assets measured on recurring basis    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash and cash equivalents, short-term investments and short-term investments under securities loan agreement 1,081 1,149
Assets held in separate accounts 116,066 109,772
Total assets 139,897 134,008
Total liabilities 212 237
Assets measured on recurring basis | Stabilizer and MCGs    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Product guarantees 8 5
Assets measured on recurring basis | Interest rate contracts    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivatives 142 147
Derivatives 191 215
Assets measured on recurring basis | Foreign exchange contracts    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivatives 9 7
Derivatives 13 17
Assets measured on recurring basis | Embedded derivatives within reinsurance    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivatives 15 23
Assets measured on recurring basis | Fixed maturities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 22,519 22,838
Assets measured on recurring basis | U.S. Treasuries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 527 470
Assets measured on recurring basis | US Government Agencies Debt Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 28 28
Assets measured on recurring basis | State, municipalities and political subdivisions    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 318 359
Assets measured on recurring basis | Debt Security, Corporate, US    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 6,213 6,012
Assets measured on recurring basis | Private Equity Funds, US    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 4,422 4,473
Assets measured on recurring basis | Foreign corporate public securities and foreign governments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 2,161 2,157
Assets measured on recurring basis | Private Equity Funds, Non-US    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 2,178 2,248
Assets measured on recurring basis | Residential mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 3,102 3,237
Assets measured on recurring basis | Commercial mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 1,649 1,879
Assets measured on recurring basis | Other asset-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 1,921 1,975
Assets measured on recurring basis | Equity securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity Securities, FV-NI 65 72
Assets measured on recurring basis | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash and cash equivalents, short-term investments and short-term investments under securities loan agreement 1,081 1,144
Assets held in separate accounts 110,230 103,956
Total assets 111,744 105,466
Total liabilities 1 0
Assets measured on recurring basis | Level 1 | Stabilizer and MCGs    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Product guarantees 0 0
Assets measured on recurring basis | Level 1 | Interest rate contracts    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivatives 1 1
Derivatives 1 0
Assets measured on recurring basis | Level 1 | Foreign exchange contracts    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivatives 0 0
Derivatives 0 0
Assets measured on recurring basis | Level 1 | Embedded derivatives within reinsurance    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivatives 0 0
Assets measured on recurring basis | Level 1 | Fixed maturities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 412 344
Assets measured on recurring basis | Level 1 | U.S. Treasuries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 412 344
Assets measured on recurring basis | Level 1 | US Government Agencies Debt Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 0 0
Assets measured on recurring basis | Level 1 | State, municipalities and political subdivisions    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 0 0
Assets measured on recurring basis | Level 1 | Debt Security, Corporate, US    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 0 0
Assets measured on recurring basis | Level 1 | Private Equity Funds, US    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 0 0
Assets measured on recurring basis | Level 1 | Foreign corporate public securities and foreign governments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 0 0
Assets measured on recurring basis | Level 1 | Private Equity Funds, Non-US    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 0 0
Assets measured on recurring basis | Level 1 | Residential mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 0 0
Assets measured on recurring basis | Level 1 | Commercial mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 0 0
Assets measured on recurring basis | Level 1 | Other asset-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 0 0
Assets measured on recurring basis | Level 1 | Equity securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity Securities, FV-NI 20 21
Assets measured on recurring basis | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash and cash equivalents, short-term investments and short-term investments under securities loan agreement 0 5
Assets held in separate accounts 5,390 5,428
Total assets 24,186 25,498
Total liabilities 203 232
Assets measured on recurring basis | Level 2 | Stabilizer and MCGs    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Product guarantees 0 0
Assets measured on recurring basis | Level 2 | Interest rate contracts    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivatives 141 146
Derivatives 190 215
Assets measured on recurring basis | Level 2 | Foreign exchange contracts    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivatives 9 7
Derivatives 13 17
Assets measured on recurring basis | Level 2 | Embedded derivatives within reinsurance    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivatives 15 23
Assets measured on recurring basis | Level 2 | Fixed maturities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 18,631 19,889
Assets measured on recurring basis | Level 2 | U.S. Treasuries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 115 126
Assets measured on recurring basis | Level 2 | US Government Agencies Debt Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 28 28
Assets measured on recurring basis | Level 2 | State, municipalities and political subdivisions    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 318 359
Assets measured on recurring basis | Level 2 | Debt Security, Corporate, US    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 6,152 5,950
Assets measured on recurring basis | Level 2 | Private Equity Funds, US    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 2,164 2,772
Assets measured on recurring basis | Level 2 | Foreign corporate public securities and foreign governments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 2,100 2,109
Assets measured on recurring basis | Level 2 | Private Equity Funds, Non-US    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 1,412 1,755
Assets measured on recurring basis | Level 2 | Residential mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 3,049 3,176
Assets measured on recurring basis | Level 2 | Commercial mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 1,649 1,879
Assets measured on recurring basis | Level 2 | Other asset-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 1,644 1,735
Assets measured on recurring basis | Level 2 | Equity securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity Securities, FV-NI 0 0
Assets measured on recurring basis | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash and cash equivalents, short-term investments and short-term investments under securities loan agreement 0 0
Assets held in separate accounts 446 388
Total assets 3,967 3,044
Total liabilities 8 5
Assets measured on recurring basis | Level 3 | Stabilizer and MCGs    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Product guarantees 8 5
Assets measured on recurring basis | Level 3 | Interest rate contracts    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivatives 0 0
Derivatives 0 0
Assets measured on recurring basis | Level 3 | Foreign exchange contracts    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivatives 0 0
Derivatives 0 0
Assets measured on recurring basis | Level 3 | Embedded derivatives within reinsurance    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivatives 0 0
Assets measured on recurring basis | Level 3 | Fixed maturities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 3,476 2,605
Assets measured on recurring basis | Level 3 | U.S. Treasuries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 0 0
Assets measured on recurring basis | Level 3 | US Government Agencies Debt Securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 0 0
Assets measured on recurring basis | Level 3 | State, municipalities and political subdivisions    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 0 0
Assets measured on recurring basis | Level 3 | Debt Security, Corporate, US    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 61 62
Assets measured on recurring basis | Level 3 | Private Equity Funds, US    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 2,258 1,701
Assets measured on recurring basis | Level 3 | Foreign corporate public securities and foreign governments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 61 48
Assets measured on recurring basis | Level 3 | Private Equity Funds, Non-US    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 766 493
Assets measured on recurring basis | Level 3 | Residential mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 53 61
Assets measured on recurring basis | Level 3 | Commercial mortgage-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 0 0
Assets measured on recurring basis | Level 3 | Other asset-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Debt Securities, Available-for-Sale, Excluding Accrued Interest 277 240
Assets measured on recurring basis | Level 3 | Equity securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity Securities, FV-NI $ 45 $ 51