Segment Reporting - Operations Reporting by Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Total revenue	$ 2,499	$ 1,707	$ 6,866	$ 4,576
Operating expenses	392	320	1,069	945
Leased vehicle expenses	1,202	629	3,163	1,423
Provision for loan losses	172	144	519	440
Interest expense	541	412	1,505	1,183
Equity income	36	29	109	85
Income before income taxes	228	231	719	670
Operating Segments [Member] | North America Segment [Member]
Segment Reporting Information [Line Items]
Total revenue	2,092	1,302	5,666	3,293
Operating expenses	240	185	656	530
Leased vehicle expenses	1,194	626	3,143	1,416
Provision for loan losses	147	106	449	335
Interest expense	383	214	1,025	572
Equity income	0	0	0	0
Income before income taxes	128	171	393	440
Operating Segments [Member] | International Segment [Member]
Segment Reporting Information [Line Items]
Total revenue	407	405	1,200	1,283
Operating expenses	152	135	413	415
Leased vehicle expenses	8	3	20	7
Provision for loan losses	25	38	70	105
Interest expense	158	175	479	564
Equity income	36	29	109	85
Income before income taxes	100	83	327	277
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Total revenue	0	2	(1)	13
Operating expenses	0	0	0	0
Leased vehicle expenses	0	0	0	0
Provision for loan losses	0	0	0	0
Interest expense	0	25	0	60
Equity income	0	0	0	0
Income before income taxes	0	(23)	(1)	(47)
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenue	0	(2)	1	(13)
Operating expenses	0	0	0	0
Leased vehicle expenses	0	0	0	0
Provision for loan losses	0	0	0	0
Interest expense	0	(2)	1	(13)
Equity income	0	0	0	0
Income before income taxes	$ 0	$ 0	$ 0	$ 0