Investments (Fixed Maturity Securities Available-For-Sale by Sector) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 297,655	$ 286,816
Gross Unrealized OTTI Loss	(33)	(25)	$ (41)
Debt Securities, Available-for-sale	327,820	298,265
Fixed Maturity Securities
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Gain	31,812	17,404
Gross Unrealized Temporary Loss	1,680	5,980
Gross Unrealized OTTI Loss	(33)	(25)
U.S. corporate
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	79,115	77,761
Gross Unrealized Gain	8,943	3,467
Gross Unrealized Temporary Loss	305	2,280
Gross Unrealized OTTI Loss	0	0
Debt Securities, Available-for-sale	87,753	78,948
Foreign government
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	58,840	56,353
Gross Unrealized Gain	8,710	6,406
Gross Unrealized Temporary Loss	321	471
Gross Unrealized OTTI Loss	0	0
Debt Securities, Available-for-sale	67,229	62,288
Foreign corporate
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	59,342	56,290
Gross Unrealized Gain	5,540	2,438
Gross Unrealized Temporary Loss	717	2,025
Gross Unrealized OTTI Loss	0	0
Debt Securities, Available-for-sale	64,165	56,703
U.S. government and agency
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	37,586	37,030
Gross Unrealized Gain	4,604	2,756
Gross Unrealized Temporary Loss	106	464
Gross Unrealized OTTI Loss	0	0
Debt Securities, Available-for-sale	42,084	39,322
RMBS
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	27,051	27,409
Gross Unrealized Gain	1,535	920
Gross Unrealized Temporary Loss	72	394
Gross Unrealized OTTI Loss	(33)	(26)
Debt Securities, Available-for-sale	28,547	27,961
ABS
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	14,547	12,552
Gross Unrealized Gain	83	74
Gross Unrealized Temporary Loss	88	153
Gross Unrealized OTTI Loss	0	(1)
Debt Securities, Available-for-sale	14,542	12,472
Municipals
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	11,081	10,376
Gross Unrealized Gain	2,001	1,228
Gross Unrealized Temporary Loss	29	71
Gross Unrealized OTTI Loss	0	0
Debt Securities, Available-for-sale	13,053	11,533
CMBS
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	10,093	9,045
Gross Unrealized Gain	396	115
Gross Unrealized Temporary Loss	42	122
Gross Unrealized OTTI Loss	0	0
Debt Securities, Available-for-sale	$ 10,447	$ 9,038

Other-than-temporary impairments on fixed maturity securities transferred to other comprehensive income loss.

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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-Publisher FASB
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