Investments (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	$ 724	$ 685	$ 1,358	$ 1,311
Investment expense	(23)	(23)	(47)	(45)
Net investment income	701	662	1,311	1,266
Fixed maturity securities
Net Investment Income [Line Items]
Gross investment income	553	536	1,096	1,058
Equity securities
Net Investment Income [Line Items]
Gross investment income	41	27		33
Gross investment income			37
Limited partnership investments
Net Investment Income [Line Items]
Gross investment income	99	81	154	137
Mortgage loans
Net Investment Income [Line Items]
Gross investment income	15	16	32	32
Short-term investments
Net Investment Income [Line Items]
Gross investment income	11	14	30	33
Trading portfolio
Net Investment Income [Line Items]
Gross investment income	1	3	1	4
Other
Net Investment Income [Line Items]
Gross investment income	4	8	8	14
Common Stock
Net Investment Income [Line Items]
Net investment income (loss)	9	15	10	15
Non-redeemable preferred stock
Net Investment Income [Line Items]
Net investment income (loss)	$ 2	$ 6	$ (3)	$ 4

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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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