Investments - Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Net Investment Income [Line Items]
Investment income, operating	$ 425	$ 501	$ 1,264	$ 1,705
Investment expenses	(21)	(18)	(62)	(56)
Net investment income	404	483	1,202	1,649
Net investment income (loss) recognized due to the change in fair value of equity and trading portfolio securities held as of September 30, 2022 and 2021	(68)	(55)	(179)	(9)
Fixed maturity securities
Net Investment Income [Line Items]
Investment income, operating	454	425	1,324	1,278
Limited partnership investments
Net Investment Income [Line Items]
Gain (losses) on investments, before investment expenses	(32)	89	(5)	285
Equity securities
Net Investment Income [Line Items]
Gain (losses) on investments, before investment expenses	2	4	(7)	53
Income (loss) from trading portfolio
Net Investment Income [Line Items]
Gain (losses) on investments, before investment expenses	(18)	(30)	(95)	46
Other
Net Investment Income [Line Items]
Investment income, operating	$ 19	$ 13	$ 47	$ 43

Amount, before investment expenses, of gains (losses) on investments.

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Trading Securities, Change in Unrealized Holding Gain (Loss), Net Investment Income Recognized

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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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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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