Segment Reporting - Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Total revenue	$ 3,561	$ 3,620
Operating expenses	358	370
Leased vehicle expenses	1,697	1,814
Provision for loan losses	466	175
Interest expense	835	947
Equity income	25	45
Income before income taxes	230	359
North America Segment [Member]
Segment Reporting Information [Line Items]
Total revenue	3,277	3,306
Operating expenses	294	276
Leased vehicle expenses	1,684	1,803
Provision for loan losses	391	139
Interest expense	738	823
Equity income	0	0
Income before income taxes	170	265
International Segment [Member]
Segment Reporting Information [Line Items]
Total revenue	284	314
Operating expenses	64	94
Leased vehicle expenses	13	11
Provision for loan losses	75	36
Interest expense	97	124
Equity income	25	45
Income before income taxes	$ 60	$ 94