Income Taxes - Components of Income Tax (Benefit) Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
US Tax Reform, Provisional Tax Expense	$ 0	$ 37	$ 130
Current
Federal	1	18	14
State	2	0	2
Foreign	78	42	54
Deferred
Federal	(19)	(2)	178
State	0	1	(3)
Foreign	(335)	14	(3)
Total income tax expense (benefit)	$ (273)	$ 73	$ 242