Investments - Components of Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Net Investment Income [Line Items]
Gross investment income	$ 924	$ 739	$ 2,609	$ 2,042
Investment expenses	(10)	(7)	(26)	(20)
Net Investment Income	914	732	2,583	2,022
Available-for-sale Securities
Net Investment Income [Line Items]
Gross investment income	907	722	2,553	1,980
Total equity securities
Net Investment Income [Line Items]
Gross investment income	17	17	56	62
Total equity securities \| Nonredeemable preferred stocks
Net Investment Income [Line Items]
Gross investment income	6	9	19	30
Total equity securities \| Common equities
Net Investment Income [Line Items]
Gross investment income	11	8	37	32
Total fixed maturities
Net Investment Income [Line Items]
Gross investment income	887	713	2,487	1,935
Total fixed maturities \| U.S. government obligations
Net Investment Income [Line Items]
Gross investment income	470	396	1,314	1,064
Total fixed maturities \| State and local government obligations
Net Investment Income [Line Items]
Gross investment income	24	16	64	42
Total fixed maturities \| Corporate and other debt securities
Net Investment Income [Line Items]
Gross investment income	214	155	593	417
Total fixed maturities \| Residential mortgage-backed securities
Net Investment Income [Line Items]
Gross investment income	38	14	95	27
Total fixed maturities \| Commercial mortgage-backed securities
Net Investment Income [Line Items]
Gross investment income	63	49	175	142
Total fixed maturities \| Other asset-backed securities
Net Investment Income [Line Items]
Gross investment income	78	83	246	243
Short-term investments
Net Investment Income [Line Items]
Gross investment income	$ 20	$ 9	$ 66	$ 45

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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