Debt Obligations 2017 Refinancing Transactions (Details) - USD ($) $ in Millions	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Long-term debt	$ 3,585		$ 3,397
13.75% Senior Secured Notes due 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	225		0
8.875% Senior Secured Notes Due 2018 [Member]
Debt Instrument [Line Items]
Long-term debt	0		706
10.375% First-Priority Senion Secured Notes due 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	560		$ 0
Debt Refinancing Transactions [Member] | 13.75% Senior Secured Notes due 2022 [Member]
Debt Instrument [Line Items]
Long-term debt		$ 225
Debt Refinancing Transactions [Member] | 10.375% First-Priority Senion Secured Notes due 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 75	$ 485