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Fair Value Measurement - Financial Instruments Carried at Fair Value (Details) - USD ($) $ in Millions | Mar. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Assets: |  |
Estimated Fair Value | $ 6,091 | $ 6,307
Fixed-maturity securities, trading | 272 | 318
Short-term investments, at fair value | 1,649 | 1,661
Other invested assets | 875 | 829
FG VIEs’ assets | 167 | 174
Other assets | 123 | 123
Liabilities: |  |
Credit derivative liabilities | 43 | 53
FG VIEs' liabilities | 399 | 554
Obligations of state and political subdivisions |  |
Assets: |  |
Estimated Fair Value | 2,331 | 2,661
U.S. government and agencies |  |
Assets: |  |
Estimated Fair Value | 55 | 60
Corporate securities |  |
Assets: |  |
Estimated Fair Value | 2,101 | 2,141
RMBS |  |
Assets: |  |
Estimated Fair Value | 402 | 342
CMBS |  |
Assets: |  |
Estimated Fair Value | 196 | 151
Non-U.S. government securities |  |
Assets: |  |
Estimated Fair Value | 84 | 100
Recurring |  |
Assets: |  |
Short-term investments, at fair value | 1,649 | 1,661
Other invested assets | 4 | 3
Other assets | 123 | 123
Total assets carried at fair value | 8,659 | 8,917
Liabilities: |  |
Credit derivative liabilities | 43 | 53
Total liabilities carried at fair value | 442 | 607
Recurring | Financial Guaranty Variable Interest Entities |  |
Liabilities: |  |
FG VIEs' liabilities | 399 | 554
Recurring | Financial Guaranty Variable Interest Entities |  |
Assets: |  |
FG VIEs’ assets | 167 | 174
Recurring | Consolidated Investment Vehicles |  |
Assets: |  |
FG VIEs’ assets | 353 | 331
Recurring | Fixed-maturity securities, available-for-sale |  |
Assets: |  |
Estimated Fair Value | 6,091 | 6,307
Fixed-maturity securities, trading | 272 | 318
Recurring | Fixed-maturity securities, available-for-sale | Obligations of state and political subdivisions |  |
Assets: |  |
Estimated Fair Value | 2,331 | 2,661
Recurring | Fixed-maturity securities, available-for-sale | U.S. government and agencies |  |
Assets: |  |
Estimated Fair Value | 55 | 60
Recurring | Fixed-maturity securities, available-for-sale | Corporate securities |  |
Assets: |  |
Estimated Fair Value | 2,101 | 2,141
Recurring | Fixed-maturity securities, available-for-sale | RMBS |  |
Assets: |  |
Estimated Fair Value | 402 | 342
Recurring | Fixed-maturity securities, available-for-sale | CMBS |  |
Assets: |  |
Estimated Fair Value | 196 | 151
Recurring | Fixed-maturity securities, available-for-sale | Asset-backed securities |  |
Assets: |  |
Estimated Fair Value | 922 | 852
Recurring | Fixed-maturity securities, available-for-sale | Non-U.S. government securities |  |
Assets: |  |
Estimated Fair Value | 84 | 100
Recurring | Fund Investments | Equity securities and warrants | Consolidated Investment Vehicles |  |
Assets: |  |
FG VIEs’ assets | 89 | 83
Recurring | Fund Investments | Structured products | Consolidated Investment Vehicles |  |
Assets: |  |
FG VIEs’ assets | 264 | 248
Recurring | Level 1 |  |
Assets: |  |
Short-term investments, at fair value | 1,649 | 1,657
Other invested assets | 0 | 0
Other assets | 61 | 55
Total assets carried at fair value | 1,710 | 1,712
Liabilities: |  |
Credit derivative liabilities | 0 | 0
Total liabilities carried at fair value | 0 | 0
Recurring | Level 1 | Financial Guaranty Variable Interest Entities |  |
Liabilities: |  |
FG VIEs' liabilities | 0 | 0
Recurring | Level 1 | Financial Guaranty Variable Interest Entities |  |
Assets: |  |
FG VIEs’ assets | 0 | 0
Recurring | Level 1 | Consolidated Investment Vehicles |  |
Assets: |  |
FG VIEs’ assets | 0 | 0
Recurring | Level 1 | Fixed-maturity securities, available-for-sale |  |
Assets: |  |
Estimated Fair Value | 0 | 0
Fixed-maturity securities, trading | 0 | 0
Recurring | Level 1 | Fixed-maturity securities, available-for-sale | Obligations of state and political subdivisions |  |
Assets: |  |
Estimated Fair Value | 0 | 0
Recurring | Level 1 | Fixed-maturity securities, available-for-sale | U.S. government and agencies |  |
Assets: |  |
Estimated Fair Value | 0 | 0
Recurring | Level 1 | Fixed-maturity securities, available-for-sale | Corporate securities |  |
Assets: |  |
Estimated Fair Value | 0 | 0
Recurring | Level 1 | Fixed-maturity securities, available-for-sale | RMBS |  |
Assets: |  |
Estimated Fair Value | 0 | 0
Recurring | Level 1 | Fixed-maturity securities, available-for-sale | CMBS |  |
Assets: |  |
Estimated Fair Value | 0 | 0
Recurring | Level 1 | Fixed-maturity securities, available-for-sale | Asset-backed securities |  |
Assets: |  |
Estimated Fair Value | 0 | 0
Recurring | Level 1 | Fixed-maturity securities, available-for-sale | Non-U.S. government securities |  |
Assets: |  |
Estimated Fair Value | 0 | 0
Recurring | Level 1 | Fund Investments | Equity securities and warrants | Consolidated Investment Vehicles |  |
Assets: |  |
FG VIEs’ assets | 0 | 0
Recurring | Level 1 | Fund Investments | Structured products | Consolidated Investment Vehicles |  |
Assets: |  |
FG VIEs’ assets | 0 | 0
Recurring | Level 2 |  |
Assets: |  |
Short-term investments, at fair value | 0 | 4
Other invested assets | 0 | 0
Other assets | 55 | 52
Total assets carried at fair value | 5,482 | 5,780
Liabilities: |  |
Credit derivative liabilities | 0 | 0
Total liabilities carried at fair value | 0 | 0
Recurring | Level 2 | Financial Guaranty Variable Interest Entities |  |
Liabilities: |  |
FG VIEs' liabilities | 0 | 0
Recurring | Level 2 | Financial Guaranty Variable Interest Entities |  |
Assets: |  |
FG VIEs’ assets | 0 | 0
Recurring | Level 2 | Consolidated Investment Vehicles |  |
Assets: |  |
FG VIEs’ assets | 44 | 62
Recurring | Level 2 | Fixed-maturity securities, available-for-sale |  |
Assets: |  |
Estimated Fair Value | 5,111 | 5,344
Fixed-maturity securities, trading | 272 | 318
Recurring | Level 2 | Fixed-maturity securities, available-for-sale | Obligations of state and political subdivisions |  |
Assets: |  |
Estimated Fair Value | 2,325 | 2,655
Recurring | Level 2 | Fixed-maturity securities, available-for-sale | U.S. government and agencies |  |
Assets: |  |
Estimated Fair Value | 55 | 60
Recurring | Level 2 | Fixed-maturity securities, available-for-sale | Corporate securities |  |
Assets: |  |
Estimated Fair Value | 2,101 | 2,141
Recurring | Level 2 | Fixed-maturity securities, available-for-sale | RMBS |  |
Assets: |  |
Estimated Fair Value | 249 | 188
Recurring | Level 2 | Fixed-maturity securities, available-for-sale | CMBS |  |
Assets: |  |
Estimated Fair Value | 196 | 151
Recurring | Level 2 | Fixed-maturity securities, available-for-sale | Asset-backed securities |  |
Assets: |  |
Estimated Fair Value | 101 | 49
Recurring | Level 2 | Fixed-maturity securities, available-for-sale | Non-U.S. government securities |  |
Assets: |  |
Estimated Fair Value | 84 | 100
Recurring | Level 2 | Fund Investments | Equity securities and warrants | Consolidated Investment Vehicles |  |
Assets: |  |
FG VIEs’ assets | 0 | 3
Recurring | Level 2 | Fund Investments | Structured products | Consolidated Investment Vehicles |  |
Assets: |  |
FG VIEs’ assets | 44 | 59
Recurring | Level 3 |  |
Assets: |  |
Short-term investments, at fair value | 0 | 0
Other invested assets | 4 | 3
Other assets | 7 | 16
Total assets carried at fair value | 1,467 | 1,425
Liabilities: |  |
Credit derivative liabilities | 43 | 53
Total liabilities carried at fair value | 442 | 607
Recurring | Level 3 | Financial Guaranty Variable Interest Entities |  |
Liabilities: |  |
FG VIEs' liabilities | 399 | 554
Recurring | Level 3 | Financial Guaranty Variable Interest Entities |  |
Assets: |  |
FG VIEs’ assets | 167 | 174
Recurring | Level 3 | Consolidated Investment Vehicles |  |
Assets: |  |
FG VIEs’ assets | 309 | 269
Recurring | Level 3 | Fixed-maturity securities, available-for-sale |  |
Assets: |  |
Estimated Fair Value | 980 | 963
Fixed-maturity securities, trading | 0 | 0
Recurring | Level 3 | Fixed-maturity securities, available-for-sale | Obligations of state and political subdivisions |  |
Assets: |  |
Estimated Fair Value | 6 | 6
Recurring | Level 3 | Fixed-maturity securities, available-for-sale | U.S. government and agencies |  |
Assets: |  |
Estimated Fair Value | 0 | 0
Recurring | Level 3 | Fixed-maturity securities, available-for-sale | Corporate securities |  |
Assets: |  |
Estimated Fair Value | 0 | 0
Recurring | Level 3 | Fixed-maturity securities, available-for-sale | RMBS |  |
Assets: |  |
Estimated Fair Value | 153 | 154
Recurring | Level 3 | Fixed-maturity securities, available-for-sale | CMBS |  |
Assets: |  |
Estimated Fair Value | 0 | 0
Recurring | Level 3 | Fixed-maturity securities, available-for-sale | Asset-backed securities |  |
Assets: |  |
Estimated Fair Value | 821 | 803
Recurring | Level 3 | Fixed-maturity securities, available-for-sale | Non-U.S. government securities |  |
Assets: |  |
Estimated Fair Value | 0 | 0
Recurring | Level 3 | Fund Investments | Equity securities and warrants | Consolidated Investment Vehicles |  |
Assets: |  |
FG VIEs’ assets | 89 | 80
Recurring | Level 3 | Fund Investments | Structured products | Consolidated Investment Vehicles |  |
Assets: |  |
FG VIEs’ assets | $ 220 | $ 189

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