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Investments - Internally Managed Investment Portfolio (Details) - USD ($) $ in Millions | Sep. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Debt and Equity Securities, FV-NI [Line Items] |  |
Estimated fair value | $ 6,278 | $ 6,369
Fixed-maturity securities, trading | 136 | 147
Short-term investments, at fair value | 1,332 | 1,221
Other invested assets | 1,012 | 926
Total investments | 8,758 | 8,663
Sound Point Capital Management, LP |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Equity method investments | 414 | 418
Total investments | 581 | 569
Equity method investments |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Equity method investments | 587 | 496
Other |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Other invested assets | $ 11 | $ 12

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