Investments - Net Investment Income and Equity in Earnings of Investees (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Net Investment Income
Gross investment income	$ 94	$ 88
Investment expenses	(2)	(1)
Net investment income	92	87
Fair value gains (losses) on trading securities	6	1
Equity in Earnings (Losses) of Investees	31	53
Fixed-maturity securities, available-for-sale:
Net Investment Income
Gross investment income	85	74
Short-term investments
Net Investment Income
Gross investment income	8	13
Other
Net Investment Income
Gross investment income	1	1
Sound Point
Net Investment Income
Equity in Earnings (Losses) of Investees	6	13
Equity method investments
Net Investment Income
Equity in Earnings (Losses) of Investees	25	40
Insured Financial Obligations, Loss Mitigation Securities
Net Investment Income
Gross investment income	3	$ 7
Fixed-Maturity Securities, Trading
Net Investment Income
Fair value gains (losses) on trading securities still held	$ 5

Amount of unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in net income (trading).

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Amount of income (loss) for proportionate share of equity method investee's income (loss).

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