Investments (Net Investment Income) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net Investment Income [Line Items]
Gross investment income	$ 4,962	$ 3,695	$ 3,687
Less: Investment expenses	147	167	201
Net investment income	4,815	3,528	3,486
Fixed maturity securities
Net Investment Income [Line Items]
Gross investment income	2,794	2,659	2,627
Equity securities
Net Investment Income [Line Items]
Gross investment income	5	6	8
Mortgage loans
Net Investment Income [Line Items]
Gross investment income	686	663	676
Policy loans
Net Investment Income [Line Items]
Gross investment income	41	34	46
Limited partnerships and LLCs
Net Investment Income [Line Items]
Gross investment income	1,391	240	220
Cash, cash equivalents and short-term investments
Net Investment Income [Line Items]
Gross investment income	3	41	72
Other
Net Investment Income [Line Items]
Gross investment income	$ 42	$ 52	$ 38

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, 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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