Investments (Fixed Maturity Securities Available-For-Sale by Sector) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	$ 293,130	$ 286,816
Gross Unrealized OTTI Loss	37	25
Estimated Fair Value of Fixed Maturity Securities AFS	326,049	298,265
Fixed Maturity Securities
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Gain	34,964	17,404
Gross Unrealized Temporary Loss	2,082	5,980
Gross Unrealized OTTI Loss	(37)	(25)
U.S. corporate
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	78,243	77,761
Gross Unrealized Gain	9,194	3,467
Gross Unrealized Temporary Loss	323	2,280
Gross Unrealized OTTI Loss	0	0
Estimated Fair Value of Fixed Maturity Securities AFS	87,114	78,948
Foreign government
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	58,318	56,353
Gross Unrealized Gain	9,663	6,406
Gross Unrealized Temporary Loss	434	471
Gross Unrealized OTTI Loss	0	0
Estimated Fair Value of Fixed Maturity Securities AFS	67,547	62,288
Foreign corporate
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	58,699	56,290
Gross Unrealized Gain	5,523	2,438
Gross Unrealized Temporary Loss	1,122	2,025
Gross Unrealized OTTI Loss	0	0
Estimated Fair Value of Fixed Maturity Securities AFS	63,100	56,703
U.S. government and agency
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	34,963	37,030
Gross Unrealized Gain	5,853	2,756
Gross Unrealized Temporary Loss	14	464
Gross Unrealized OTTI Loss	0	0
Estimated Fair Value of Fixed Maturity Securities AFS	40,802	39,322
RMBS
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	27,889	27,409
Gross Unrealized Gain	1,728	920
Gross Unrealized Temporary Loss	63	394
Gross Unrealized OTTI Loss	(37)	(26)
Estimated Fair Value of Fixed Maturity Securities AFS	29,591	27,961
ABS
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	14,319	12,552
Gross Unrealized Gain	111	74
Gross Unrealized Temporary Loss	85	153
Gross Unrealized OTTI Loss	0	1
Estimated Fair Value of Fixed Maturity Securities AFS	14,345	12,472
Municipals
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	10,600	10,376
Gross Unrealized Gain	2,348	1,228
Gross Unrealized Temporary Loss	6	71
Gross Unrealized OTTI Loss	0	0
Estimated Fair Value of Fixed Maturity Securities AFS	12,942	11,533
CMBS
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	10,099	9,045
Gross Unrealized Gain	544	115
Gross Unrealized Temporary Loss	35	122
Gross Unrealized OTTI Loss	0	0
Estimated Fair Value of Fixed Maturity Securities AFS	$ 10,608	$ 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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