Income Taxes - Components of Income Tax (Benefit) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Current	$ 126	$ 12
Deferred	(157)	0
Total Income Tax (Benefit) Expense	$ 31	$ (12)
Effective Tax Rate	(5.70%)	20.30%