Investments and Cash - Investment Portfolio Carrying Value (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Schedule of Cost-method Investments [Line Items]
Fixed-maturity securities, available-for-sale	$ 6,369	$ 6,307
Fixed-maturity securities, trading	147	318
Short-term investments	1,221	1,661
Other invested assets:
Other invested assets	926	829
Total investments	8,663	9,115
Sound Point
Other invested assets:
Equity method investments	418	429
Total investments	569	202
Funds and other investments
Other invested assets:
Other invested assets	496	394
Other
Other invested assets:
Other invested assets	$ 12	$ 6