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Amount of allowance for credit loss on 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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Investments (Reconciliation Of Available-For-Sale Securities From Cost Basis To Fair Value) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020
Amortized cost, gross unrealized gains, losses, OTTI and fair value of AFS securities
Allowance for Credit Losses	$ 9	$ 14	$ 13	$ 21	$ 18
Fixed Maturity AFS Securities [Member]
Amortized cost, gross unrealized gains, losses, OTTI and fair value of AFS securities
Amortized Cost	105,530		103,021
Gross Unrealized Gains	15,235		18,287
Gross Unrealized Losses	304		184
Allowance for Credit Losses	9		13
Fair Value	120,452		121,111
Corporate Bonds [Member]
Amortized cost, gross unrealized gains, losses, OTTI and fair value of AFS securities
Allowance for Credit Losses	8	13	12	19	$ 18
Corporate Bonds [Member] \| Fixed Maturity AFS Securities [Member]
Amortized cost, gross unrealized gains, losses, OTTI and fair value of AFS securities
Amortized Cost	86,931		85,625
Gross Unrealized Gains	13,132		15,947
Gross Unrealized Losses	248		136
Allowance for Credit Losses	8		12
Fair Value	99,807		101,424
ABS [Member]
Amortized cost, gross unrealized gains, losses, OTTI and fair value of AFS securities
Allowance for Credit Losses				1
ABS [Member] \| Fixed Maturity AFS Securities [Member]
Amortized cost, gross unrealized gains, losses, OTTI and fair value of AFS securities
Amortized Cost	8,033		7,035
Gross Unrealized Gains	159		158
Gross Unrealized Losses	22		15
Fair Value	8,170		7,178
U.S. Government Bonds [Member] \| Fixed Maturity AFS Securities [Member]
Amortized cost, gross unrealized gains, losses, OTTI and fair value of AFS securities
Amortized Cost	355		369
Gross Unrealized Gains	58		81
Gross Unrealized Losses	2		1
Fair Value	411		449
Foreign Government Bonds [Member] \| Fixed Maturity AFS Securities [Member]
Amortized cost, gross unrealized gains, losses, OTTI and fair value of AFS securities
Amortized Cost	391		380
Gross Unrealized Gains	66		86
Gross Unrealized Losses	3		1
Fair Value	454		465
RMBS [Member]
Amortized cost, gross unrealized gains, losses, OTTI and fair value of AFS securities
Allowance for Credit Losses	1	$ 1	1	$ 1
RMBS [Member] \| Fixed Maturity AFS Securities [Member]
Amortized cost, gross unrealized gains, losses, OTTI and fair value of AFS securities
Amortized Cost	2,541		2,551
Gross Unrealized Gains	256		289
Gross Unrealized Losses	1		1
Allowance for Credit Losses	1		1
Fair Value	2,795		2,838
CMBS [Member] \| Fixed Maturity AFS Securities [Member]
Amortized cost, gross unrealized gains, losses, OTTI and fair value of AFS securities
Amortized Cost	1,489		1,380
Gross Unrealized Gains	86		115
Gross Unrealized Losses	6
Fair Value	1,569		1,495
State And Municipal Bonds [Member] \| Fixed Maturity AFS Securities [Member]
Amortized cost, gross unrealized gains, losses, OTTI and fair value of AFS securities
Amortized Cost	5,292		5,145
Gross Unrealized Gains	1,374		1,517
Gross Unrealized Losses	7
Fair Value	6,659		6,662
Hybrid And Redeemable Preferred Securities [Member] \| Fixed Maturity AFS Securities [Member]
Amortized cost, gross unrealized gains, losses, OTTI and fair value of AFS securities
Amortized Cost	498		536
Gross Unrealized Gains	104		94
Gross Unrealized Losses	15		30
Fair Value	$ 587		$ 600