Investments (Details) - Net Investment Income - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net investment income
Gross investment income	$ 2,508	$ 2,513	$ 2,435
Investment expenses	40	39	38
Net investment income	2,468	2,474	2,397
Fixed maturities [Member]
Net investment income
Gross investment income	2,070	1,980	1,895
Equity securities [Member]
Net investment income
Gross investment income	15	16	28
Short-term securities [Member]
Net investment income
Gross investment income	105	92	62
Real estate [Member]
Net investment income
Gross investment income	55	48	44
Other investments [Member]
Net investment income
Gross investment income	$ 263	$ 377	$ 406

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.

+ References

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