Condensed Consolidated Statement of Equity (Deficit) - 6 months ended Jun. 30, 2018 - USD ($) $ in Millions	Total	Common Stock [Member]	Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income [Member]	Accumulated Deficit [Member]	Parent [Member]	Noncontrolling Interest [Member]
Balance at Dec. 31, 2017	$ (2,742)	$ 1	$ 526	$ (296)	$ (8)	$ (2,964)	$ (2,741)	$ (1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(34)	0	0	0	0	(35)	(35)	1
Other comprehensive income	(2)	0	0	0	(2)	0	(2)	0
Impact of change in accounting policy	1	0	0	0	0	1	1	0
Balance at Jun. 30, 2018	$ (2,777)	$ 1	$ 526	$ (296)	$ (10)	$ (2,998)	$ (2,777)	$ 0