Investments (Fixed Maturity Securities Available-For-Sale by Sector) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	$ 288,559	$ 286,816
Gross Unrealized OTTI Loss	29	25
Estimated Fair Value of Fixed Maturity Securities AFS	308,410	298,265
Fixed Maturity Securities
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Gain	22,662	17,404
Gross Unrealized Temporary Loss	2,840	5,980
Gross Unrealized OTTI Loss	(29)	(25)
U.S. corporate
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	75,893	77,761
Gross Unrealized Gain	5,040	3,467
Gross Unrealized Temporary Loss	787	2,280
Gross Unrealized OTTI Loss	0	0
Estimated Fair Value of Fixed Maturity Securities AFS	80,146	78,948
Foreign government
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	57,483	56,353
Gross Unrealized Gain	7,749	6,406
Gross Unrealized Temporary Loss	277	471
Gross Unrealized OTTI Loss	0	0
Estimated Fair Value of Fixed Maturity Securities AFS	64,955	62,288
Foreign corporate
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	57,640	56,290
Gross Unrealized Gain	3,504	2,438
Gross Unrealized Temporary Loss	1,199	2,025
Gross Unrealized OTTI Loss	0	0
Estimated Fair Value of Fixed Maturity Securities AFS	59,945	56,703
U.S. government and agency
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	37,819	37,030
Gross Unrealized Gain	3,413	2,756
Gross Unrealized Temporary Loss	224	464
Gross Unrealized OTTI Loss	0	0
Estimated Fair Value of Fixed Maturity Securities AFS	41,008	39,322
RMBS
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	27,439	27,409
Gross Unrealized Gain	1,097	920
Gross Unrealized Temporary Loss	206	394
Gross Unrealized OTTI Loss	(30)	(26)
Estimated Fair Value of Fixed Maturity Securities AFS	28,360	27,961
ABS
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	12,635	12,552
Gross Unrealized Gain	77	74
Gross Unrealized Temporary Loss	80	153
Gross Unrealized OTTI Loss	1	1
Estimated Fair Value of Fixed Maturity Securities AFS	12,631	12,472
Municipals
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	10,371	10,376
Gross Unrealized Gain	1,546	1,228
Gross Unrealized Temporary Loss	19	71
Gross Unrealized OTTI Loss	0	0
Estimated Fair Value of Fixed Maturity Securities AFS	11,898	11,533
CMBS
Debt Securities, Available-for-sale [Line Items]
Cost or Amortized Cost	9,279	9,045
Gross Unrealized Gain	236	115
Gross Unrealized Temporary Loss	48	122
Gross Unrealized OTTI Loss	0	0
Estimated Fair Value of Fixed Maturity Securities AFS	$ 9,467	$ 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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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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