Supplemental Condensed Consolidating Financial Information - Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Condensed Statement of Income Captions [Line Items]
Net (loss) income	$ (230)	$ 33	$ (153)	$ 57
Other comprehensive income, net of tax	0	2	1	8
Comprehensive (loss) income	(230)	35	(152)	65
Eliminations
Condensed Statement of Income Captions [Line Items]
Net (loss) income	241	(47)	197	(82)
Other comprehensive income, net of tax	0	(2)	(1)	(7)
Comprehensive (loss) income	241	(49)	196	(89)
Parent Guarantor \| Reportable Legal Entities
Condensed Statement of Income Captions [Line Items]
Net (loss) income	(230)	33	(153)	57
Other comprehensive income, net of tax	0	2	1	8
Comprehensive (loss) income	(230)	35	(152)	65
Other Guarantors \| Reportable Legal Entities
Condensed Statement of Income Captions [Line Items]
Net (loss) income	(63)	1	(66)	3
Other comprehensive income, net of tax	0	0	0	0
Comprehensive (loss) income	(63)	1	(66)	3
Non-Guarantors \| Reportable Legal Entities
Condensed Statement of Income Captions [Line Items]
Net (loss) income	(178)	46	(131)	79
Other comprehensive income, net of tax	0	2	1	7
Comprehensive (loss) income	$ (178)	$ 48	$ (130)	$ 86

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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