Income Taxes - Components of United States and Foreign Tax (Benefit) Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal	$ 0	$ (15)	$ (22)
Foreign	134	188	166
State	17	(1)	3
Current income tax expense (benefit)	151	172	147
Deferred:
Federal	133	120	389
Foreign	153	6	(8)
State	37	5	(15)
Deferred income tax expense (benefit)	323	131	366
United States and Foreign Tax (Benefit) Expense	$ 474	$ 303	$ 513