Investments (Fixed Maturity Securities Available-For-Sale by Sector) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 302,624	$ 297,655
Amortized cost of fixed maturity securities valuation allowances	(187)	0
Gross Unrealized OTTI Loss	0	(33)
Debt Securities, Available-for-sale	326,685	327,820
Fixed Maturity Securities
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Gain	32,005	31,812
Gross Unrealized Temporary Loss	7,757	1,680
Gross Unrealized OTTI Loss		(33)
U.S. corporate
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	80,287	79,115
Amortized cost of fixed maturity securities valuation allowances	(51)	0
Gross Unrealized Gain	7,151	8,943
Gross Unrealized Temporary Loss	2,316	305
Gross Unrealized OTTI Loss		0
Debt Securities, Available-for-sale	85,071	87,753
Foreign government
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	57,737	58,840
Amortized cost of fixed maturity securities valuation allowances	(136)	0
Gross Unrealized Gain	7,816	8,710
Gross Unrealized Temporary Loss	573	321
Gross Unrealized OTTI Loss		0
Debt Securities, Available-for-sale	64,844	67,229
Foreign corporate
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	58,679	59,342
Amortized cost of fixed maturity securities valuation allowances	0
Gross Unrealized Gain	3,281	5,540
Gross Unrealized Temporary Loss	2,765	717
Gross Unrealized OTTI Loss		0
Debt Securities, Available-for-sale	59,195	64,165
U.S. government and agency
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	38,181	37,586
Amortized cost of fixed maturity securities valuation allowances	0
Gross Unrealized Gain	9,787	4,604
Gross Unrealized Temporary Loss	9	106
Gross Unrealized OTTI Loss		0
Debt Securities, Available-for-sale	47,959	42,084
RMBS
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	29,242	27,051
Amortized cost of fixed maturity securities valuation allowances	0
Gross Unrealized Gain	1,636	1,535
Gross Unrealized Temporary Loss	409	72
Gross Unrealized OTTI Loss		(33)
Debt Securities, Available-for-sale	30,469	28,547
ABS
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	15,870	14,547
Amortized cost of fixed maturity securities valuation allowances	0
Gross Unrealized Gain	48	83
Gross Unrealized Temporary Loss	1,080	88
Gross Unrealized OTTI Loss		0
Debt Securities, Available-for-sale	14,838	14,542
Municipals
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	11,877	11,081
Amortized cost of fixed maturity securities valuation allowances	0
Gross Unrealized Gain	2,054	2,001
Gross Unrealized Temporary Loss	60	29
Gross Unrealized OTTI Loss		0
Debt Securities, Available-for-sale	13,871	13,053
CMBS
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	10,751	10,093
Amortized cost of fixed maturity securities valuation allowances	0
Gross Unrealized Gain	232	396
Gross Unrealized Temporary Loss	545	42
Gross Unrealized OTTI Loss		0
Debt Securities, Available-for-sale	$ 10,438	$ 10,447

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