Segment Information (Narrative) (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Assets Under Vehicle Programs	$ 14,388	$ 12,779
Americas [Member]
Segment Reporting Information [Line Items]
Segment Assets Exclusive Of Assets Under Vehicle Program	5,800	3,800
Assets Under Vehicle Programs	10,800	9,700
International [Member]
Segment Reporting Information [Line Items]
Segment Assets Exclusive Of Assets Under Vehicle Program	2,800	2,500
Assets Under Vehicle Programs	$ 3,600	$ 3,100