Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ (22)	$ 10	$ (383)	$ 42
Other comprehensive income (loss):
Foreign currency translation adjustments	3	(11)	(28)
Comprehensive income (loss)	$ (19)	$ (1)	$ (411)	$ 42