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Fair Value Measurements - Assets and liabilities measured and carried at fair value in the financial statements (Details) - USD ($) $ in Millions | Dec. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Assets: |  |
Available for sale (AFS) fixed maturities | $ 10,398 | $ 10,377
Trading fixed maturities | 76 | 57
Equity securities, at fair value | 751 | 1,018
Assets of managed investment entities | 4,140 | 4,484
Other assets — derivatives | 82 | 87
Total assets accounted for at fair value | 15,366 | 15,942
Liabilities: |  |
Liabilities of managed investment entities | 3,965 | 4,307
Other liabilities — derivatives | 18 | 22
Total liabilities accounted for at fair value | 3,985 | 4,331
Contingent consideration - acquisitions |  |
Liabilities: |  |
Contingent consideration — acquisitions | 2 | 2
Other liabilities — derivatives |  |
Liabilities: |  |
Other liabilities — derivatives | 18 | 22
Fixed maturities |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 10,398 | 10,377
Trading fixed maturities | 76 | 57
U.S. Government and government agencies |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 173 | 236
States, municipalities and political subdivisions |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 859 | 984
Foreign government |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 237 | 230
Residential MBS |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 1,989 | 1,658
Commercial MBS |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 51 | 74
Collateralized loan obligations |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 1,237 | 1,687
Other asset-backed securities |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 2,356 | 2,362
Corporate and other |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 3,496 | 3,146
Equity securities |  |
Assets: |  |
Equity securities, at fair value | 751 | 1,018
Other assets |  |
Assets: |  |
Other assets — derivatives | 1 | 6
Level 1 |  |
Assets: |  |
Assets of managed investment entities | 419 | 335
Total assets accounted for at fair value | 1,023 | 1,079
Liabilities: |  |
Liabilities of managed investment entities | 402 | 322
Total liabilities accounted for at fair value | 402 | 322
Level 1 | Contingent consideration - acquisitions |  |
Liabilities: |  |
Contingent consideration — acquisitions | 0 | 0
Level 1 | Other liabilities — derivatives |  |
Liabilities: |  |
Other liabilities — derivatives | 0 | 0
Level 1 | Fixed maturities |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 185 | 244
Trading fixed maturities | 0 | 0
Level 1 | U.S. Government and government agencies |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 173 | 235
Level 1 | States, municipalities and political subdivisions |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 0 | 0
Level 1 | Foreign government |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 0 | 0
Level 1 | Residential MBS |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 0 | 0
Level 1 | Commercial MBS |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 0 | 0
Level 1 | Collateralized loan obligations |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 0 | 0
Level 1 | Other asset-backed securities |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 0 | 0
Level 1 | Corporate and other |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 12 | 9
Level 1 | Equity securities |  |
Assets: |  |
Equity securities, at fair value | 419 | 500
Level 1 | Other assets |  |
Assets: |  |
Other assets — derivatives | 0 | 0
Level 2 |  |
Assets: |  |
Assets of managed investment entities | 3,711 | 4,140
Total assets accounted for at fair value | 13,247 | 13,633
Liabilities: |  |
Liabilities of managed investment entities | 3,553 | 3,976
Total liabilities accounted for at fair value | 3,571 | 3,998
Level 2 | Contingent consideration - acquisitions |  |
Liabilities: |  |
Contingent consideration — acquisitions | 0 | 0
Level 2 | Other liabilities — derivatives |  |
Liabilities: |  |
Other liabilities — derivatives | 18 | 22
Level 2 | Fixed maturities |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 9,445 | 9,397
Trading fixed maturities | 50 | 57
Level 2 | U.S. Government and government agencies |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 0 | 1
Level 2 | States, municipalities and political subdivisions |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 858 | 982
Level 2 | Foreign government |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 237 | 230
Level 2 | Residential MBS |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 1,988 | 1,656
Level 2 | Commercial MBS |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 51 | 74
Level 2 | Collateralized loan obligations |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 1,237 | 1,686
Level 2 | Other asset-backed securities |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 2,060 | 2,011
Level 2 | Corporate and other |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 3,014 | 2,757
Level 2 | Equity securities |  |
Assets: |  |
Equity securities, at fair value | 40 | 33
Level 2 | Other assets |  |
Assets: |  |
Other assets — derivatives | 1 | 6
Level 3 |  |
Assets: |  |
Assets of managed investment entities | 10 | 9
Total assets accounted for at fair value | 1,096 | 1,230
Liabilities: |  |
Liabilities of managed investment entities | 10 | 9
Total liabilities accounted for at fair value | 12 | 11
Level 3 | Contingent consideration - acquisitions |  |
Liabilities: |  |
Contingent consideration — acquisitions | 2 | 2
Level 3 | Other liabilities — derivatives |  |
Liabilities: |  |
Other liabilities — derivatives | 0 | 0
Level 3 | Fixed maturities |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 768 | 736
Trading fixed maturities | 26 | 0
Level 3 | U.S. Government and government agencies |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 0 | 0
Level 3 | States, municipalities and political subdivisions |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 1 | 2
Level 3 | Foreign government |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 0 | 0
Level 3 | Residential MBS |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 1 | 2
Level 3 | Commercial MBS |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 0 | 0
Level 3 | Collateralized loan obligations |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 0 | 1
Level 3 | Other asset-backed securities |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 296 | 351
Level 3 | Corporate and other |  |
Assets: |  |
Available for sale (AFS) fixed maturities | 470 | 380
Level 3 | Equity securities |  |
Assets: |  |
Equity securities, at fair value | 292 | 485
Level 3 | Other assets |  |
Assets: |  |
Other assets — derivatives | $ 0 | $ 0

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