Investments (Details) - Net Investment Income - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net investment income
Gross investment income	$ 2,513	$ 2,435	$ 2,340
Investment expenses	39	38	38
Net Investment income	2,474	2,397	2,302
Fixed maturities [Member]
Net investment income
Gross investment income	1,980	1,895	1,981
Equity securities [Member]
Net investment income
Gross investment income	16	28	37
Short-term securities [Member]
Net investment income
Gross investment income	92	62	29
Real estate [Member]
Net investment income
Gross investment income	48	44	51
Other investments [Member]
Net investment income
Gross investment income	$ 377	$ 406	$ 242

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.

+ References

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