Investments (Fixed Maturity Securities Available-For-Sale by Sector) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 304,767	$ 310,811
Allowance for Credit Loss for Debt Securities	(104)	(81)	$ (187)	$ 0
Estimated Fair Value of Fixed Maturity Securities AFS	332,941	354,809
Fixed Maturity Securities
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Gain	31,251	45,519
Gross Unrealized Temporary Loss	2,973	1,440
U.S. corporate
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	79,513	79,788
Allowance for Credit Loss for Debt Securities	(43)	(44)	(51)	0
Gross Unrealized Gain	9,080	13,924
Gross Unrealized Temporary Loss	548	252
Estimated Fair Value of Fixed Maturity Securities AFS	88,002	93,416
Foreign government
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	60,896	63,243
Allowance for Credit Loss for Debt Securities	(21)	(21)	(136)	0
Gross Unrealized Gain	6,970	8,883
Gross Unrealized Temporary Loss	708	406
Estimated Fair Value of Fixed Maturity Securities AFS	67,137	71,699
Foreign corporate
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	60,042	60,995
Allowance for Credit Loss for Debt Securities	(33)	(16)	0	0
Gross Unrealized Gain	6,395	8,897
Gross Unrealized Temporary Loss	521	468
Estimated Fair Value of Fixed Maturity Securities AFS	65,883	69,408
U.S. government and agency
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	37,827	39,094
Allowance for Credit Loss for Debt Securities	0	0
Gross Unrealized Gain	4,370	8,095
Gross Unrealized Temporary Loss	795	89
Estimated Fair Value of Fixed Maturity Securities AFS	41,402	47,100
RMBS
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	27,772	28,415
Allowance for Credit Loss for Debt Securities	0	0
Gross Unrealized Gain	1,726	2,062
Gross Unrealized Temporary Loss	196	42
Estimated Fair Value of Fixed Maturity Securities AFS	29,302	30,435
ABS
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	16,049	16,963
Allowance for Credit Loss for Debt Securities	0	0
Gross Unrealized Gain	208	231
Gross Unrealized Temporary Loss	40	75
Estimated Fair Value of Fixed Maturity Securities AFS	16,217	17,119
Municipals
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	11,321	10,982
Allowance for Credit Loss for Debt Securities	0	0
Gross Unrealized Gain	1,976	2,746
Gross Unrealized Temporary Loss	85	6
Estimated Fair Value of Fixed Maturity Securities AFS	13,212	13,722
CMBS
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	11,347	11,331
Allowance for Credit Loss for Debt Securities	(7)	0	$ 0	$ 0
Gross Unrealized Gain	526	681
Gross Unrealized Temporary Loss	80	102
Estimated Fair Value of Fixed Maturity Securities AFS	$ 11,786	$ 11,910

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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