Segment Reporting and Geographic Information - Operations Reporting by Assets (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Finance receivables, net	$ 42,172	$ 33,475
Leased vehicles, net	42,882	34,342	$ 20,100
Total assets	97,015	87,765
Assets held for sale	0	10,951
North America [Member]
Segment Reporting Information [Line Items]
Finance receivables, net	35,436	27,617
Leased vehicles, net	42,753	34,284
Total assets	87,618	68,656
International [Member]
Segment Reporting Information [Line Items]
Finance receivables, net	6,736	5,858
Leased vehicles, net	129	58
Total assets	$ 9,397	$ 19,109