Income Taxes - Components of Income Tax (Benefit) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Current	$ 21	$ 23	$ 37	$ 149
Deferred	(1)	(7)	(101)	(164)
Total Income Tax Expense (Benefit)	$ 20	$ 16	$ (64)	$ (15)
Effective Tax Rate	71.40%	160.00%	18.60%	(2.70%)

Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration