Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ (224)	$ 32	$ (253)	$ 100
Other comprehensive income (loss):
Foreign currency translation adjustments	(46)	(22)	(72)	(21)
Comprehensive income (loss)	$ (270)	$ 10	$ (325)	$ 79