Income Tax (Net Deferred Income Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deferred income tax assets:
Policyholder liabilities and receivables	$ 2,887	$ 2,654
Net operating loss carryforwards	104	512
Employee benefits	705	802
Capital loss carryforwards	0	6
Tax credit carryforwards	1,113	1,322
Litigation-related and government mandated	161	160
Other	191	657
Total gross deferred income tax assets	5,161	6,113
Less: Valuation allowance	169	189
Total net deferred income tax assets	4,992	5,924
Deferred income tax liabilities:
Investments, including derivatives	2,494	2,772
Intangibles	1,256	1,321
Net unrealized investment gains	2,898	4,783
DAC	3,263	3,206
Other	495	609
Total deferred income tax liabilities	10,406	12,691
Deferred tax assets and liabilities [Abstract]
Net deferred income tax asset (liability)	$ (5,414)	$ (6,767)