Investments (Net investment income) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Net Investment Income [Line Items]
Gross investment income	$ 634	$ 626
Investment expense	(24)	(22)
Net investment income	610	604
Fixed maturity securities
Net Investment Income [Line Items]
Gross investment income	543	522
Equity securities
Net Investment Income [Line Items]
Gross investment income		6
Gross investment expense	(4)
Limited partnership investments
Net Investment Income [Line Items]
Gross investment income	55	56
Mortgage loans
Net Investment Income [Line Items]
Gross investment income	17	16
Short-term investments
Net Investment Income [Line Items]
Gross investment income	19	19
Trading portfolio
Net Investment Income [Line Items]
Gross investment income	0	1
Other
Net Investment Income [Line Items]
Gross investment income	4	6
Common Stock
Net Investment Income [Line Items]
Net investment income (loss)	(8)	(4)
Non-redeemable preferred stock
Net Investment Income [Line Items]
Net investment income (loss)	$ (5)	$ (2)

Gross Investment Loss, Operating

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Amount of unrealized and realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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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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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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