Investments - Gross Unrealized Appreciation (Depreciation) on Debt Securities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 15,775
Allowance for Credit Loss	(23)
Unrealized Appreciation	1,337
Unrealized Depreciation	(131)
Fair Value	16,958
Amortized Cost		$ 16,220
Allowance for Credit Loss		(26)
Unrealized Appreciation		1,990
Unrealized Depreciation		(53)
Fair Value		18,131
Run-Off Settlement Annuity Business
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,262
Allowance for Credit Loss	(5)
Unrealized Appreciation	720
Unrealized Depreciation	(10)
Fair Value	2,967
Amortized Cost		2,282
Allowance for Credit Loss		(5)
Unrealized Appreciation		838
Unrealized Depreciation		(3)
Fair Value		3,112
Federal government and agency
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	287
Allowance for Credit Loss	0
Unrealized Appreciation	101
Unrealized Depreciation	(1)
Fair Value	387
Amortized Cost		334
Allowance for Credit Loss		0
Unrealized Appreciation		122
Unrealized Depreciation		0
Fair Value		456
State and local government
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	154
Allowance for Credit Loss	0
Unrealized Appreciation	17
Unrealized Depreciation	0
Fair Value	171
Amortized Cost		150
Allowance for Credit Loss		0
Unrealized Appreciation		17
Unrealized Depreciation		0
Fair Value		167
Foreign government
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,468
Allowance for Credit Loss	0
Unrealized Appreciation	194
Unrealized Depreciation	(46)
Fair Value	2,616
Amortized Cost		2,201
Allowance for Credit Loss		0
Unrealized Appreciation		318
Unrealized Depreciation		(8)
Fair Value		2,511
Corporate
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	12,361
Allowance for Credit Loss	(23)
Unrealized Appreciation	1,008
Unrealized Depreciation	(80)
Fair Value	13,266
Amortized Cost		13,108
Allowance for Credit Loss		(19)
Unrealized Appreciation		1,506
Unrealized Depreciation		(33)
Fair Value		14,562
Mortgage and other asset-backed
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	505
Allowance for Credit Loss	0
Unrealized Appreciation	17
Unrealized Depreciation	(4)
Fair Value	$ 518
Amortized Cost		427
Allowance for Credit Loss		(7)
Unrealized Appreciation		27
Unrealized Depreciation		(12)
Fair Value		$ 435

Available For Sale Debt Securities Amortized Cost Basis Before Reclassification To Disposal Group Assets Held For Sale

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Available For Sale Securities Accumulated Gross Unrealized Gain Before Tax Before Reclassification To Disposal Group Assets Held For Sale

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Available For Sale Securities Accumulated Gross Unrealized Loss Before Tax Before Reclassification To Disposal Group Assets Held For Sale

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Debt Securities, Available For Sale, Allowance For Credit Loss, Before Reclassification To Disposal Group Assets Held For Sale

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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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