CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net loss	$ (48)	$ (53)	$ (45)	$ (37)	$ 39	$ (70)	$ (96)	$ (42)	$ (183)	$ (169)	$ (304)
Net impact of interest rate derivative instruments, net of tax									19	34	(10)
Comprehensive loss									$ (164)	$ (135)	$ (314)