Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 112	$ 55	$ 138	$ 72
Other comprehensive income (loss), net of income taxes:
Currency translation adjustment	1		(1)
Employee benefit plans				(1)
Other comprehensive income (loss), net of income taxes	1		(1)	(1)
Comprehensive income	$ 113	$ 55	$ 137	$ 71