Fair Value Measurements (excluding Consolidated Investment Entities) - Fair Value Measurement (Details) - USD ($) $ in Millions | Dec. 31, 2024 | Dec. 31, 2023 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets held in separate accounts | $ 101,676 | $ 93,133 |
Total assets | 163,889 | 157,085 |
Derivatives | 332 | 371 |
Total liabilities | 157,882 | 151,032 |
Fixed maturities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 27,454 | 28,611 |
U.S. Treasuries | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 472 | 403 |
U.S. Government agencies and authorities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 30 | 56 |
State, municipalities, and political subdivisions | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 580 | 771 |
U.S. corporate public securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 7,008 | 7,666 |
U.S. corporate private securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 4,983 | 4,760 |
Foreign corporate public securities and foreign governments | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 2,472 | 2,702 |
Foreign corporate private securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 2,537 | 2,812 |
Residential mortgage-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 3,471 | 3,476 |
Commercial mortgage-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 3,132 | 3,495 |
Other asset-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 2,769 | 2,470 |
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 agreements | 2,535 | 2,165 |
Assets held in separate accounts | 101,676 | 93,133 |
Total assets | 132,269 | 124,517 |
Contingent consideration liability | 2 | 51 |
Total liabilities | 394 | 480 |
Assets measured on recurring basis | Stabilizer and MCGs | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Investment contract liabilities | 19 | 9 |
Assets measured on recurring basis | Credit Default Swap | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivatives | 2 | 2 |
Assets measured on recurring basis | Interest rate contracts | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivatives | 246 | 270 |
Derivatives | 313 | 354 |
Assets measured on recurring basis | Foreign exchange contracts | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivatives | 55 | 37 |
Derivatives | 8 | 13 |
Assets measured on recurring basis | Equity contracts | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivatives | 2 | 4 |
Derivatives | 9 | 2 |
Assets measured on recurring basis | Embedded derivatives on reinsurance . | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivatives | 55 | 61 |
Embedded derivative on reinsurance liability | (41) | (49) |
Assets measured on recurring basis | Fixed maturities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 27,454 | 28,611 |
Assets measured on recurring basis | U.S. Treasuries | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 472 | 403 |
Assets measured on recurring basis | U.S. Government agencies and authorities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 30 | 56 |
Assets measured on recurring basis | State, municipalities, and political subdivisions | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 580 | 771 |
Assets measured on recurring basis | U.S. corporate public securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 7,008 | 7,666 |
Assets measured on recurring basis | U.S. corporate private securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 4,983 | 4,760 |
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] | | |
Fixed maturities, including securities pledged | 2,472 | 2,702 |
Assets measured on recurring basis | Foreign corporate private securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 2,537 | 2,812 |
Assets measured on recurring basis | Residential mortgage-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 3,471 | 3,476 |
Assets measured on recurring basis | Commercial mortgage-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 3,132 | 3,495 |
Assets measured on recurring basis | Other asset-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 2,769 | 2,470 |
Assets measured on recurring basis | Equity securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Equity securities | 246 | 236 |
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 agreements | 2,511 | 2,148 |
Assets held in separate accounts | 95,946 | 87,180 |
Total assets | 99,007 | 89,821 |
Contingent consideration liability | 0 | 0 |
Total liabilities | 11 | 0 |
Assets measured on recurring basis | Level 1 | Stabilizer and MCGs | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Investment contract liabilities | 0 | 0 |
Assets measured on recurring basis | Level 1 | Credit Default Swap | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivatives | 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 | 0 | 7 |
Derivatives | 11 | 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 | Equity 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 on reinsurance . | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivatives | 0 | |
Embedded derivative on reinsurance liability | 0 | 0 |
Assets measured on recurring basis | Level 1 | Fixed maturities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 402 | 346 |
Assets measured on recurring basis | Level 1 | U.S. Treasuries | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 402 | 346 |
Assets measured on recurring basis | Level 1 | U.S. Government agencies and authorities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 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] | | |
Fixed maturities, including securities pledged | 0 | 0 |
Assets measured on recurring basis | Level 1 | U.S. corporate public securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 0 | 0 |
Assets measured on recurring basis | Level 1 | U.S. corporate private securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 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] | | |
Fixed maturities, including securities pledged | 0 | 0 |
Assets measured on recurring basis | Level 1 | Foreign corporate private securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 0 | 0 |
Assets measured on recurring basis | Level 1 | Residential mortgage-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 0 | 0 |
Assets measured on recurring basis | Level 1 | Commercial mortgage-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 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] | | |
Fixed maturities, including securities pledged | 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 | 148 | 140 |
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 agreements | 1 | 17 |
Assets held in separate accounts | 5,390 | 5,605 |
Total assets | 30,674 | 32,162 |
Contingent consideration liability | 0 | 0 |
Total liabilities | 309 | 362 |
Assets measured on recurring basis | Level 2 | Stabilizer and MCGs | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Investment contract liabilities | 0 | 0 |
Assets measured on recurring basis | Level 2 | Credit Default Swap | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivatives | 2 | 2 |
Assets measured on recurring basis | Level 2 | Interest rate contracts | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivatives | 246 | 263 |
Derivatives | 302 | 354 |
Assets measured on recurring basis | Level 2 | Foreign exchange contracts | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivatives | 55 | 37 |
Derivatives | 8 | 13 |
Assets measured on recurring basis | Level 2 | Equity contracts | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivatives | 2 | 4 |
Derivatives | 9 | 2 |
Assets measured on recurring basis | Level 2 | Embedded derivatives on reinsurance . | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivatives | 55 | 61 |
Embedded derivative on reinsurance liability | (12) | (9) |
Assets measured on recurring basis | Level 2 | Fixed maturities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 24,925 | 26,175 |
Assets measured on recurring basis | Level 2 | U.S. Treasuries | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 70 | 57 |
Assets measured on recurring basis | Level 2 | U.S. Government agencies and authorities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 30 | 55 |
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] | | |
Fixed maturities, including securities pledged | 580 | 771 |
Assets measured on recurring basis | Level 2 | U.S. corporate public securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 6,949 | 7,648 |
Assets measured on recurring basis | Level 2 | U.S. corporate private securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 3,486 | 3,234 |
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] | | |
Fixed maturities, including securities pledged | 2,412 | 2,702 |
Assets measured on recurring basis | Level 2 | Foreign corporate private securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 2,116 | 2,376 |
Assets measured on recurring basis | Level 2 | Residential mortgage-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 3,404 | 3,419 |
Assets measured on recurring basis | Level 2 | Commercial mortgage-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 3,132 | 3,495 |
Assets measured on recurring basis | Level 2 | Other asset-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 2,746 | 2,418 |
Assets measured on recurring basis | Level 2 | Equity securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Equity securities | 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 agreements | 23 | 0 |
Assets held in separate accounts | 340 | 348 |
Total assets | 2,588 | 2,534 |
Contingent consideration liability | 2 | 51 |
Total liabilities | 74 | 118 |
Assets measured on recurring basis | Level 3 | Stabilizer and MCGs | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Investment contract liabilities | 19 | 9 |
Assets measured on recurring basis | Level 3 | Credit Default Swap | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivatives | 0 | 0 |
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 | Equity 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 on reinsurance . | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Derivatives | 0 | 0 |
Embedded derivative on reinsurance liability | (53) | (58) |
Assets measured on recurring basis | Level 3 | Fixed maturities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 2,127 | 2,090 |
Assets measured on recurring basis | Level 3 | U.S. Treasuries | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 0 | 0 |
Assets measured on recurring basis | Level 3 | U.S. Government agencies and authorities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 0 | 1 |
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] | | |
Fixed maturities, including securities pledged | 0 | 0 |
Assets measured on recurring basis | Level 3 | U.S. corporate public securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 59 | 18 |
Assets measured on recurring basis | Level 3 | U.S. corporate private securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 1,497 | 1,526 |
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] | | |
Fixed maturities, including securities pledged | 60 | 0 |
Assets measured on recurring basis | Level 3 | Foreign corporate private securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 421 | 436 |
Assets measured on recurring basis | Level 3 | Residential mortgage-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 67 | 57 |
Assets measured on recurring basis | Level 3 | Commercial mortgage-backed securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Fixed maturities, including securities pledged | 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] | | |
Fixed maturities, including securities pledged | 23 | 52 |
Assets measured on recurring basis | Level 3 | Equity securities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Equity securities | $ 98 | $ 96 |