Segment Reporting - Operations Reporting by Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Total revenue	$ 2,879	$ 2,075
Operating expenses	392	334
Leased vehicle expenses	1,438	893
Provision for loan losses	217	196
Interest expense	619	463
Equity income	47	36
Income before income taxes	260	225
Operating Segments [Member] | North America Segment [Member]
Segment Reporting Information [Line Items]
Total revenue	2,474	1,688
Operating expenses	248	201
Leased vehicle expenses	1,426	888
Provision for loan losses	187	177
Interest expense	455	305
Equity income	0	0
Income before income taxes	158	117
Operating Segments [Member] | International Segment [Member]
Segment Reporting Information [Line Items]
Total revenue	405	387
Operating expenses	144	133
Leased vehicle expenses	12	5
Provision for loan losses	30	19
Interest expense	164	157
Equity income	47	36
Income before income taxes	102	109
Corporate [Member]
Segment Reporting Information [Line Items]
Total revenue	0	(1)
Operating expenses	0	0
Leased vehicle expenses	0	0
Provision for loan losses	0	0
Interest expense	0	0
Equity income	0	0
Income before income taxes	0	(1)
Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenue	0	1
Operating expenses	0	0
Leased vehicle expenses	0	0
Provision for loan losses	0	0
Interest expense	0	1
Equity income	0	0
Income before income taxes	$ 0	$ 0