Segment Reporting - Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Total revenue	$ 3,146	$ 3,426	$ 6,302	$ 6,833
Operating expenses	393	378	766	789
Leased vehicle expenses	856	825	1,711	2,069
Provision for loan losses	198	59	320	33
Interest expense	642	633	1,219	1,283
Equity income	50	50	104	104
Income before income taxes	1,106	1,581	2,390	2,763
North America Segment
Segment Reporting Information [Line Items]
Total revenue	2,904	3,188	5,834	6,359
Operating expenses	315	302	618	641
Leased vehicle expenses	842	813	1,685	2,044
Provision for loan losses	170	36	268	(8)
Interest expense	560	575	1,067	1,167
Equity income	0	0	0	0
Income before income taxes	1,017	1,462	2,197	2,515
International Segment
Segment Reporting Information [Line Items]
Total revenue	242	238	468	474
Operating expenses	79	76	148	148
Leased vehicle expenses	13	12	26	25
Provision for loan losses	28	23	52	41
Interest expense	82	58	152	116
Equity income	50	50	104	104
Income before income taxes	$ 89	$ 119	$ 194	$ 248