Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income		$ 5	$ 13
Other comprehensive income:
Foreign currency translation adjustments	[1]	8	7
Total other comprehensive income		8	7
Comprehensive income		$ 13	$ 20

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