Investments - Components of Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Net Investment Income [Line Items]
Gross investment income	$ 917	$ 814
Investment expenses	(8)	(7)
Net Investment Income	909	807
Available-for-sale Securities
Net Investment Income [Line Items]
Gross investment income	900	792
Total equity securities
Net Investment Income [Line Items]
Gross investment income	17	22
Total equity securities \| Nonredeemable preferred stocks
Net Investment Income [Line Items]
Gross investment income	4	8
Total equity securities \| Common equities
Net Investment Income [Line Items]
Gross investment income	13	14
Total fixed maturities
Net Investment Income [Line Items]
Gross investment income	856	774
Total fixed maturities \| U.S. government
Net Investment Income [Line Items]
Gross investment income	400	422
Total fixed maturities \| State and local government
Net Investment Income [Line Items]
Gross investment income	24	19
Total fixed maturities \| Corporate and other debt
Net Investment Income [Line Items]
Gross investment income	235	171
Total fixed maturities \| Residential mortgage-backed
Net Investment Income [Line Items]
Gross investment income	39	25
Total fixed maturities \| Commercial mortgage-backed
Net Investment Income [Line Items]
Gross investment income	71	53
Total fixed maturities \| Other asset-backed
Net Investment Income [Line Items]
Gross investment income	87	84
Short-term investments
Net Investment Income [Line Items]
Gross investment income	$ 44	$ 18

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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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