Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (56)	$ (224)	$ (163)	$ (253)
Other comprehensive income (loss):
Foreign currency translation adjustments	(3)	(46)	12	(72)
Comprehensive loss	$ (59)	$ (270)	$ (151)	$ (325)