Income Tax (Net Deferred Income Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Tax Credit Carryforward [Line Items]
Deferred Tax Liabilities, Other	$ 134	$ 0
Tax Credit Carryforward, Amount	922	1,296
Deferred income tax assets:
Policyholder liabilities and receivables	3,890	3,635
Net operating loss carryforwards (1)	301	240
Employee benefits	673	692
Capital loss carryforwards	9	10
Tax credit carryforwards (2)	922	1,296
Litigation-related and government mandated	126	151
Other	0	127
Total gross deferred income tax assets	5,921	6,151
Less: Valuation allowance (1)	309	294
Total net deferred income tax assets	5,612	5,857
Deferred income tax liabilities:
Investments, including derivatives	4,421	4,170
Intangibles	1,387	1,181
Net unrealized investment gains	7,422	6,226
DAC	3,162	3,312
Other	134	0
Total deferred income tax liabilities	16,526	14,889
Net deferred income tax asset (liability) (3)	(10,914)	(9,032)
Deferred tax assets and liabilities [Abstract]
Deferred Income Tax Liabilities, Net	11,008	9,097
General Business Tax Credit Carryforward [Member] | 2037and2040 [Member]
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Amount	94
Deferred income tax assets:
Tax credit carryforwards (2)	94
Other Assets
Deferred tax assets and liabilities [Abstract]
Deferred Tax Assets, Net	94	$ 65
Certain State and Foreign Net Operating Loss Carryforwards
Tax Credit Carryforward [Line Items]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ 301