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Investments - Internally Managed Investment Portfolio (Details) - USD ($) $ in Millions | Sep. 30, 2024 | Dec. 31, 2023
--- | --- | ---
Debt and Equity Securities, FV-NI [Line Items] |  |
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
Total investments | $ 8,846 | $ 9,115
Fixed-maturity investments, non-investment grade, percent | 9.10% | 9.20%
Sound Point Capital Management, LP |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Equity method investments | $ 417 | $ 429
Total investments | 288 | 202
Externally managed |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Estimated fair value | 5,554 | 5,372
Loss Mitigation Securities |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Estimated fair value | 468 | 459
Other |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Estimated fair value | 262 | 476
Contingent Value Instruments |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Fixed-maturity securities, trading | 136 | 318
Alternative Investment |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Equity method investments | 487 | 394
Alternative Investment | Consolidated Investment Vehicles |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Equity method investments | 278 | 305
Other |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Other invested assets | $ 8 | $ 6

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