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Fair Value Measurement - Financial Instruments Carried at Fair Value (Details) - USD ($) $ in Millions | Sep. 30, 2024 | Dec. 31, 2023
--- | --- | ---
Assets: |  |
Estimated Fair Value | $ 6,284 | $ 6,307
Fixed-maturity securities, trading | 163 | 318
Short-term investments, at fair value | 1,487 | 1,661
Other invested assets | 912 | 829
FG VIEs’ assets | 156 | 174
Other assets | 129 | 123
Liabilities: |  |
Credit derivative liabilities | 39 | 53
FG VIEs' liabilities | 392 | 554
Obligations of state and political subdivisions |  |
Assets: |  |
Estimated Fair Value | 2,119 | 2,661
U.S. government and agencies |  |
Assets: |  |
Estimated Fair Value | 71 | 60
Corporate securities |  |
Assets: |  |
Estimated Fair Value | 2,404 | 2,141
RMBS |  |
Assets: |  |
Estimated Fair Value | 544 | 342
CMBS |  |
Assets: |  |
Estimated Fair Value | 180 | 151
Non-U.S. government securities |  |
Assets: |  |
Estimated Fair Value | 75 | 100
Recurring |  |
Assets: |  |
Short-term investments, at fair value | 1,487 | 1,661
Other invested assets | 5 | 3
Other assets | 129 | 123
Total assets carried at fair value | 8,558 | 8,917
Liabilities: |  |
Credit derivative liabilities | 39 | 53
Total liabilities carried at fair value | 431 | 607
Recurring | Financial Guaranty Variable Interest Entities |  |
Liabilities: |  |
FG VIEs' liabilities | 392 | 554
Recurring | Financial Guaranty Variable Interest Entities |  |
Assets: |  |
FG VIEs’ assets | 156 | 174
Recurring | Consolidated Investment Vehicles |  |
Assets: |  |
FG VIEs’ assets | 334 | 331
Recurring | Fixed-maturity securities, available-for-sale |  |
Assets: |  |
Estimated Fair Value | 6,284 | 6,307
Fixed-maturity securities, trading | 163 | 318
Recurring | Fixed-maturity securities, available-for-sale | Obligations of state and political subdivisions |  |
Assets: |  |
Estimated Fair Value | 2,119 | 2,661
Recurring | Fixed-maturity securities, available-for-sale | U.S. government and agencies |  |
Assets: |  |
Estimated Fair Value | 71 | 60
Recurring | Fixed-maturity securities, available-for-sale | Corporate securities |  |
Assets: |  |
Estimated Fair Value | 2,404 | 2,141
Recurring | Fixed-maturity securities, available-for-sale | RMBS |  |
Assets: |  |
Estimated Fair Value | 544 | 342
Recurring | Fixed-maturity securities, available-for-sale | CMBS |  |
Assets: |  |
Estimated Fair Value | 180 | 151
Recurring | Fixed-maturity securities, available-for-sale | Asset-backed securities |  |
Assets: |  |
Estimated Fair Value | 891 | 852
Recurring | Fixed-maturity securities, available-for-sale | Non-U.S. government securities |  |
Assets: |  |
Estimated Fair Value | 75 | 100
Recurring | Fund Investments | Equity securities and warrants | Consolidated Investment Vehicles |  |
Assets: |  |
FG VIEs’ assets | 97 | 83
Recurring | Fund Investments | Structured products | Consolidated Investment Vehicles |  |
Assets: |  |
FG VIEs’ assets | 237 | 248
Recurring | Level 1 |  |
Assets: |  |
Short-term investments, at fair value | 1,482 | 1,657
Other invested assets | 0 | 0
Other assets | 64 | 55
Total assets carried at fair value | 1,546 | 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 | 5 | 4
Other invested assets | 0 | 0
Other assets | 59 | 52
Total assets carried at fair value | 5,559 | 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 | 0 | 62
Recurring | Level 2 | Fixed-maturity securities, available-for-sale |  |
Assets: |  |
Estimated Fair Value | 5,338 | 5,344
Fixed-maturity securities, trading | 157 | 318
Recurring | Level 2 | Fixed-maturity securities, available-for-sale | Obligations of state and political subdivisions |  |
Assets: |  |
Estimated Fair Value | 2,112 | 2,655
Recurring | Level 2 | Fixed-maturity securities, available-for-sale | U.S. government and agencies |  |
Assets: |  |
Estimated Fair Value | 71 | 60
Recurring | Level 2 | Fixed-maturity securities, available-for-sale | Corporate securities |  |
Assets: |  |
Estimated Fair Value | 2,404 | 2,141
Recurring | Level 2 | Fixed-maturity securities, available-for-sale | RMBS |  |
Assets: |  |
Estimated Fair Value | 392 | 188
Recurring | Level 2 | Fixed-maturity securities, available-for-sale | CMBS |  |
Assets: |  |
Estimated Fair Value | 180 | 151
Recurring | Level 2 | Fixed-maturity securities, available-for-sale | Asset-backed securities |  |
Assets: |  |
Estimated Fair Value | 104 | 49
Recurring | Level 2 | Fixed-maturity securities, available-for-sale | Non-U.S. government securities |  |
Assets: |  |
Estimated Fair Value | 75 | 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 | 0 | 59
Recurring | Level 3 |  |
Assets: |  |
Short-term investments, at fair value | 0 | 0
Other invested assets | 5 | 3
Other assets | 6 | 16
Total assets carried at fair value | 1,453 | 1,425
Liabilities: |  |
Credit derivative liabilities | 39 | 53
Total liabilities carried at fair value | 431 | 607
Recurring | Level 3 | Financial Guaranty Variable Interest Entities |  |
Liabilities: |  |
FG VIEs' liabilities | 392 | 554
Recurring | Level 3 | Financial Guaranty Variable Interest Entities |  |
Assets: |  |
FG VIEs’ assets | 156 | 174
Recurring | Level 3 | Consolidated Investment Vehicles |  |
Assets: |  |
FG VIEs’ assets | 334 | 269
Recurring | Level 3 | Fixed-maturity securities, available-for-sale |  |
Assets: |  |
Estimated Fair Value | 946 | 963
Fixed-maturity securities, trading | 6 | 0
Recurring | Level 3 | Fixed-maturity securities, available-for-sale | Obligations of state and political subdivisions |  |
Assets: |  |
Estimated Fair Value | 7 | 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 | 152 | 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 | 787 | 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 | 97 | 80
Recurring | Level 3 | Fund Investments | Structured products | Consolidated Investment Vehicles |  |
Assets: |  |
FG VIEs’ assets | $ 237 | $ 189

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