Schedule of Goodwill (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Line Items]
Gross goodwill			$ 3,125
Goodwill [Roll Forward]
Goodwill	$ 1,073	$ 1,007
Goodwill, Impaired, Accumulated Impairment Loss			(2,118)
Acquisition	54	5
Adjustments to the allocation of purchase price	(35)	61
Goodwill	1,092	1,073
Americas
Goodwill [Line Items]
Gross goodwill			2,139
Goodwill [Roll Forward]
Goodwill	552	552
Goodwill, Impaired, Accumulated Impairment Loss			1,587
Acquisition	0	0
Adjustments to the allocation of purchase price	(13)	0
Goodwill	539	552
International
Goodwill [Line Items]
Gross goodwill			986
Goodwill [Roll Forward]
Goodwill	521	455
Goodwill, Impaired, Accumulated Impairment Loss			$ 531
Acquisition	54	5
Adjustments to the allocation of purchase price	(22)	61
Goodwill	$ 553	$ 521