Income Taxes - Components of Income Tax (Benefit) Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Foreign:
Current	$ 206	$ 213	$ 253
Deferred	29	3	(1)
Federal:
Current	9	4	(5)
Deferred	(5)	16	(2)
Total income tax expense	$ 239	$ 236	$ 245