Goodwill and Intangibles - Schedule of Goodwill Balance and Related Activity (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill beginning balance, gross	$ 2,706	$ 2,751
Distribution to parent, gross		(41)
Goodwill ending balance, gross	2,708	2,706
Accumulated impairment losses, beginning balance	(2,102)	(2,134)
Accumulated impairment losses, distribution to parent		32
Accumulated impairment losses, ending balance	(2,102)	(2,102)
Goodwill, beginning balance	604	617
Distribution to parent		(9)
Foreign currency translation	2	(4)
Goodwill, ending balance	$ 606	$ 604