Investments - Components of Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Net Investment Income [Line Items]
Gross investment income	$ 979	$ 871	$ 1,896	$ 1,685
Investment expenses	(10)	(9)	(18)	(16)
Net Investment Income	969	862	1,878	1,669
Available-for-sale Securities
Net Investment Income [Line Items]
Gross investment income	966	854	1,866	1,646
Total equity securities
Net Investment Income [Line Items]
Gross investment income	13	17	30	39
Total equity securities \| Nonredeemable preferred stocks
Net Investment Income [Line Items]
Gross investment income	2	5	6	13
Total equity securities \| Common equities
Net Investment Income [Line Items]
Gross investment income	11	12	24	26
Total fixed maturities
Net Investment Income [Line Items]
Gross investment income	950	826	1,806	1,600
Total fixed maturities \| U.S. government
Net Investment Income [Line Items]
Gross investment income	433	422	833	844
Total fixed maturities \| State and local government
Net Investment Income [Line Items]
Gross investment income	27	21	51	40
Total fixed maturities \| Corporate and other debt
Net Investment Income [Line Items]
Gross investment income	253	208	488	379
Total fixed maturities \| Residential mortgage-backed
Net Investment Income [Line Items]
Gross investment income	54	32	93	57
Total fixed maturities \| Commercial mortgage-backed
Net Investment Income [Line Items]
Gross investment income	83	59	154	112
Total fixed maturities \| Other asset-backed
Net Investment Income [Line Items]
Gross investment income	100	84	187	168
Short-term investments
Net Investment Income [Line Items]
Gross investment income	$ 16	$ 28	$ 60	$ 46

Amount, before investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

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Amount of expenses related to the generation of investment income.

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Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

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