Segment Reporting - Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Total revenue	$ 3,423	$ 3,639	$ 6,984	$ 7,259
Operating expenses	345	377	703	747
Leased vehicle expenses	1,779	1,637	3,476	3,451
Provision for loan losses	327	179	793	354
Interest expense	788	952	1,623	1,899
Equity income	42	42	67	87
Income before income taxes	226	536	456	895
North America Segment [Member]
Segment Reporting Information [Line Items]
Total revenue	3,197	3,332	6,474	6,638
Operating expenses	273	281	567	557
Leased vehicle expenses	1,768	1,627	3,452	3,430
Provision for loan losses	244	142	635	281
Interest expense	710	831	1,448	1,654
Equity income	0	0	0	0
Income before income taxes	202	451	372	716
International Segment [Member]
Segment Reporting Information [Line Items]
Total revenue	226	307	510	621
Operating expenses	72	96	136	190
Leased vehicle expenses	11	10	24	21
Provision for loan losses	83	37	158	73
Interest expense	78	121	175	245
Equity income	42	42	67	87
Income before income taxes	$ 24	$ 85	$ 84	$ 179