Segment Reporting and Geographic Information - Operations Reporting by Assets (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Finance receivables, net (Note 4) ($23,109 and $21,781 in VIEs; Note 8)	$ 33,000	$ 29,282
Total assets	47,724	37,990
North America Segment [Member]
Segment Reporting Information [Line Items]
Finance receivables, net (Note 4) ($23,109 and $21,781 in VIEs; Note 8)	15,943	12,878
Total assets	27,687	19,094
International Segment [Member]
Segment Reporting Information [Line Items]
Finance receivables, net (Note 4) ($23,109 and $21,781 in VIEs; Note 8)	17,057	16,404
Total assets	$ 20,037	$ 18,896