Income Tax (Net Deferred Income Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Deferred income tax assets:
Policyholder liabilities and receivables	$ 1,405	$ 1,734
Net operating loss carryforwards	1,420	1,229
Employee benefits	1,099	1,094
Capital loss carryforwards	9	9
Tax credit carryforwards	1,574	1,264
Litigation-related and government mandated	256	260
Other	798	858
Total gross deferred income tax assets	6,561	6,448
Less: Valuation allowance	161	203
Total net deferred income tax assets	6,400	6,245
Deferred income tax liabilities:
Investments, including derivatives	2,615	4,469
Intangibles	1,505	1,606
Net unrealized investment gains	6,093	5,639
DAC	5,367	5,000
Other	187	123
Total deferred income tax liabilities	15,767	16,837
Deferred tax assets and liabilities [Abstract]
Net deferred income tax asset (liability)	$ (9,367)	$ (10,592)