Segment Reporting and Geographic Information - Operations Reporting by Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Total finance receivables, net	$ 58,390	$ 53,473
Leased vehicles, net	184	226
Total assets	113,825	109,217
North America [Member]
Segment Reporting Information [Line Items]
Total finance receivables, net	53,332	46,679
Total assets	105,507	99,453
International [Member]
Segment Reporting Information [Line Items]
Total finance receivables, net	5,058	6,794
Total assets	8,318	9,764
Assets Leased to Others [Member]
Segment Reporting Information [Line Items]
Leased vehicles, net	39,819	42,055
Assets Leased to Others [Member] | North America [Member]
Segment Reporting Information [Line Items]
Leased vehicles, net	39,656	41,881
Assets Leased to Others [Member] | International [Member]
Segment Reporting Information [Line Items]
Leased vehicles, net	$ 163	$ 174