Income Taxes - Components of United States and Foreign Tax (Benefit) Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal	$ (25)	$ 0	$ 0
Foreign	175	154	135
State	2	(1)	1
Current income tax expense (benefit)	152	153	136
Deferred:
Federal	77	74	(2,103)
Foreign	(328)	5	84
State	22	0	49
Deferred income tax expense (benefit)	(229)	79	(1,970)
United States and Foreign Tax (Benefit) Expense	$ (77)	$ 232	$ (1,834)