Investments - Internally Managed Investment Portfolio (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Debt and Equity Securities, FV-NI [Line Items]
Estimated fair value	$ 6,415	$ 6,369
Fixed-maturity securities, trading	137	147
Short-term investments, at fair value	1,158	1,221
Other invested assets	960	926
Total investments	8,670	8,663
Sound Point Capital Management, LP
Debt and Equity Securities, FV-NI [Line Items]
Equity method investments	411	418
Total investments	547	569
Equity method investments
Debt and Equity Securities, FV-NI [Line Items]
Equity method investments	531	496
Other
Debt and Equity Securities, FV-NI [Line Items]
Other invested assets	$ 18	$ 12

Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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