Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income		$ 32	$ 27	$ 36	$ 40
Other comprehensive income (loss):
Foreign currency translation adjustments	[1]	(17)	13	(9)	20
Total other comprehensive income (loss)		(17)	13	(9)	20
Comprehensive income		$ 15	$ 40	$ 27	$ 60

[1] Foreign currency translation adjustments exclude income taxes due to our intention to indefinitely reinvest the earnings of our foreign subsidiaries in those operations.