Investments (Details) - Net Investment Income - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net investment income
Gross investment income	$ 2,966	$ 2,605	$ 3,073
Investment expenses	44	43	40
Net investment income	2,922	2,562	3,033
Fixed maturities [Member]
Net investment income
Gross investment income	2,472	2,113	1,989
Equity securities [Member]
Net investment income
Gross investment income	18	17	19
Short-term securities [Member]
Net investment income
Gross investment income	241	73	7
Real estate [Member]
Net investment income
Gross investment income	64	66	59
Other investments [Member]
Net investment income
Gross investment income	$ 171	$ 336	$ 999

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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