Investments (Net Investment Income) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net Investment Income [Line Items]
Less: Investment expenses	$ 1,422	$ 1,285	$ 1,122
Net Investment Income	18,868	16,166	17,363
Securities Investment
Net Investment Income [Line Items]
Gross Investment Income, Operating	18,815	18,134	17,185
Net Investment Income	17,393	16,849	16,063
Fixed Maturity Securities
Net Investment Income [Line Items]
Gross Investment Income, Operating	11,886	11,946	11,497
Equity securities
Net Investment Income [Line Items]
Gross Investment Income, Operating	61	64	129
FVO Securities (1)
Net Investment Income [Line Items]
Gross Investment Income, Operating	184	51	68
Mortgage loans
Net Investment Income [Line Items]
Gross Investment Income, Operating	3,782	3,340	3,082
Policy loans
Net Investment Income [Line Items]
Gross Investment Income, Operating	512	506	517
Real estate and real estate joint ventures
Net Investment Income [Line Items]
Gross Investment Income, Operating	676	694	646
Other limited partnership interests
Net Investment Income [Line Items]
Gross Investment Income, Operating	825	731	798
Cash, cash equivalents and short-term investments
Net Investment Income [Line Items]
Gross Investment Income, Operating	457	387	228
Operating joint ventures
Net Investment Income [Line Items]
Gross Investment Income, Operating	84	51	28
Other
Net Investment Income [Line Items]
Gross Investment Income, Operating	348	364	192
Unit-linked investments (1)
Net Investment Income [Line Items]
Net Investment Income	1,475	(683)	1,300
Trading Securities, Change in Unrealized Holding Gain (Loss)	$ 1,000	$ (771)	$ 662

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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-SubTopic 220
-Section S99
-Paragraph 1
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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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