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Investments - Internally Managed Investment Portfolio (Details) - USD ($) $ in Millions | Mar. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Debt and Equity Securities, FV-NI [Line Items] |  |
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
Total investments | $ 8,887 | $ 9,115
Fixed-maturity investments, non-investment grade, percent | 9.50% | 9.20%
Sound Point Capital Management, LP |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Equity method investments | $ 417 | $ 429
Total investments | 636 | 631
Externally managed |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Estimated fair value | 5,383 | 5,372
Loss Mitigation Securities |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Estimated fair value | 464 | 459
Other |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Estimated fair value | 244 | 476
Alternative Investment |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Equity method investments | 451 | 394
Other |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Other invested assets | $ 7 | $ 6

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