Investments (Net Investment Income) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net Investment Income [Line Items]
Net investment income	$ 2,774	$ 2,749	$ 7,423	$ 8,188
Less: Investment expenses	153	258	540	782
Securities investment
Net Investment Income [Line Items]
Gross Investment Income, Operating	2,927	3,007	7,963	8,970
Fixed maturity securities AFS
Net Investment Income [Line Items]
Gross Investment Income, Operating	1,635	1,724	4,929	5,272
Equity securities
Net Investment Income [Line Items]
Gross Investment Income, Operating	5	8	19	27
Mortgage loans
Net Investment Income [Line Items]
Gross Investment Income, Operating	711	772	2,134	2,322
Policy loans
Net Investment Income [Line Items]
Gross Investment Income, Operating	77	77	230	230
Real estate and real estate joint ventures
Net Investment Income [Line Items]
Gross Investment Income, Operating	41	104	163	283
Other limited partnership interests
Net Investment Income [Line Items]
Net investment income	370	171	194	429
Cash, cash equivalents and short-term investments
Net Investment Income [Line Items]
Gross Investment Income, Operating	11	57	72	144
FVO Securities (1)
Net Investment Income [Line Items]
Gross Investment Income, Operating	19	25	21	58
FVO securities, Change in Unrealized Holding Gain (Loss)	18	25	20	58
Operating joint ventures
Net Investment Income [Line Items]
Gross Investment Income, Operating	20	10	67	55
Other
Net Investment Income [Line Items]
Gross Investment Income, Operating	$ 38	$ 59	$ 134	$ 150

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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