Finance Receivables - Finance Receivables, net (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables, net	$ 35,074	$ 33,000
North America Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables, net	19,853	15,943
International Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables, net	15,221	17,057
Consumer Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collectively evaluated for impairment, net of fees	26,472	24,389
Individually evaluated for impairment, net of fees	1,515	1,234
Total finance receivables	27,987	25,623
Less: allowance for loan losses - collective	(503)	(483)
Less: allowance for loan losses - specific	(215)	(172)
Total finance receivables, net	27,269	24,968
Consumer Finance Receivables [Member] | North America Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collectively evaluated for impairment, net of fees	15,479	12,127
Individually evaluated for impairment, net of fees	1,515	1,234
Total finance receivables	16,994	13,361
Less: allowance for loan losses - collective	(408)	(405)
Less: allowance for loan losses - specific	(215)	(172)
Total finance receivables, net	16,371	12,784
Consumer Finance Receivables [Member] | North America Segment [Member] | Post-Acquisition Portfolio [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Deferred Income	167	245
Consumer Finance Receivables [Member] | International Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collectively evaluated for impairment, net of fees	10,993	12,262
Individually evaluated for impairment, net of fees	0	0
Total finance receivables	10,993	12,262
Less: allowance for loan losses - collective	(95)	(78)
Less: allowance for loan losses - specific	0	0
Total finance receivables, net	10,898	12,184
Loans and Leases Receivable, Gross, Consumer, Lease Financing	1,100	1,000
Commercial Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collectively evaluated for impairment, net of fees	7,793	7,983
Individually evaluated for impairment, net of fees	52	89
Total finance receivables	7,845	8,072	$ 7,151	$ 6,700
Less: allowance for loan losses - collective	(33)	(35)
Less: allowance for loan losses - specific	(7)	(5)
Total finance receivables, net	7,805	8,032
Commercial Finance Receivables [Member] | North America Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collectively evaluated for impairment, net of fees	3,498	3,180
Individually evaluated for impairment, net of fees	5	0
Total finance receivables	3,503	3,180	2,513	1,975
Less: allowance for loan losses - collective	(20)	(21)
Less: allowance for loan losses - specific	(1)	0
Total finance receivables, net	3,482	3,159
Commercial Finance Receivables [Member] | International Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collectively evaluated for impairment, net of fees	4,295	4,803
Individually evaluated for impairment, net of fees	47	89
Total finance receivables	4,342	4,892	$ 4,638	$ 4,725
Less: allowance for loan losses - collective	(13)	(14)
Less: allowance for loan losses - specific	(6)	(5)
Total finance receivables, net	$ 4,323	$ 4,873