Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ (234)	$ (502)	$ 116
Other comprehensive loss:
Foreign currency translation adjustments	(8)	(89)	(45)
Comprehensive income (loss)	$ (242)	$ (591)	$ 71