Income Tax (Net Deferred Income Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred income tax assets:
Investments, including derivatives	$ 313	$ 357
Deferred Tax Assets, Operating Loss Carryforwards	416	0
Tax credit carryforwards	191	184
Deferred Tax Assets, Goodwill and Intangible Assets	227	0
Other	74	55
Deferred Tax Assets, Valuation Allowance	11	0
Deferred Tax Assets, Net	1,221	596
Total deferred income tax assets	1,210	596
Deferred Tax Liabilities, Deferred Expense, Reserves and Accruals	853	536
Deferred income tax liabilities:
Intangibles	0	293
Net unrealized investment gains	494	653
DAC	757	1,565
Total deferred income tax liabilities	2,104	3,047
Deferred tax assets and liabilities [Abstract]
Net deferred income tax asset (liability)	$ (894)	$ (2,451)