Income Tax (Net Deferred Income Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Deferred income tax assets:
Policyholder liabilities and receivables	$ 3,635	$ 3,558
Net operating loss carryforwards (1)	240	237
Employee benefits	692	705
Capital loss carryforwards	10	0
Tax credit carryforwards (2)	1,296	1,113
Litigation-related and government mandated	151	161
Other	127	365
Total gross deferred income tax assets	6,151	6,139
Less: Valuation allowance (1)	294	302
Total net deferred income tax assets	5,857	5,837
Deferred income tax liabilities:
Investments, including derivatives	4,170	3,854
Intangibles	1,181	1,256
Net unrealized investment gains	6,226	2,898
DAC	3,312	3,243
Total deferred income tax liabilities	14,889	11,251
Deferred tax assets and liabilities [Abstract]
Net deferred income tax asset (liability) (3)	(9,097)	$ (5,414)
Certain State and Foreign Net Operating Loss Carryforwards
Tax Credit Carryforward [Line Items]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ 240