Finance Receivables Finance Receivables, net (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Mar. 31, 2013	Dec. 31, 2012		Sep. 30, 2012
Finance Receivables, net [Line Items]
Financing Receivable, Gross	$ 11,467	[1]		$ 10,993	[1]
Notes, Loans and Financing Receivable, Net	23,867			10,998
Loans and Leases Receivable, Net Amount	23,867			10,998
North America [Member]
Finance Receivables, net [Line Items]
Loans and Leases Receivable, Net Amount	12,232
International [Member]
Finance Receivables, net [Line Items]
Loans and Leases Receivable, Net Amount	11,635
Commercial Loan [Member]
Finance Receivables, net [Line Items]
Post-Acquisition Finance Receivables, Carrying Value				560
Financing Receivable, Gross	5,246			560
Allowance for Notes, Loans and Financing Receivable	(29)		(24)	(6)
Notes, Loans and Financing Receivable, Net	5,217
Financing Receivable, Collectively Evaluated for Impairment	5,167
Financing Receivable, Individually Evaluated for Impairment	79
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	(25)
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	(4)
Loans and Leases Receivable, Net Amount	5,246
Commercial Loan [Member] | North America [Member]
Finance Receivables, net [Line Items]
Post-Acquisition Finance Receivables, Carrying Value				560
Allowance for Notes, Loans and Financing Receivable	(13)		(12)	(6)
Notes, Loans and Financing Receivable, Net	1,344			554
Financing Receivable, Collectively Evaluated for Impairment	1,355			560
Financing Receivable, Individually Evaluated for Impairment	2
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	(12)			(6)
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	(1)
Loans and Leases Receivable, Net Amount	1,357					284
Commercial Loan [Member] | International [Member]
Finance Receivables, net [Line Items]
Allowance for Notes, Loans and Financing Receivable	(16)		(12)
Notes, Loans and Financing Receivable, Net	3,873
Financing Receivable, Collectively Evaluated for Impairment	3,812
Financing Receivable, Individually Evaluated for Impairment	77
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	(13)
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	(3)
Loans and Leases Receivable, Net Amount	3,889
Consumer Loan [Member]
Finance Receivables, net [Line Items]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Outstanding Balance	1,599
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net	1,452
Post-Acquisition Finance Receivables, Carrying Value	17,665
Financing Receivable, Gross	19,117
Allowance for Notes, Loans and Financing Receivable	(467)
Notes, Loans and Financing Receivable, Net	18,650
Loans and Leases Receivable, Net Amount	17,665
Consumer Loan [Member] | North America [Member]
Finance Receivables, net [Line Items]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Outstanding Balance	1,154			2,162
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net	1,028			1,958
Post-Acquisition Finance Receivables, Carrying Value	10,313			8,831
Financing Receivable, Gross	11,341			10,789
Allowance for Notes, Loans and Financing Receivable	(453)			(345)
Notes, Loans and Financing Receivable, Net	10,888			10,444
Loans and Leases Receivable, Net Amount	10,313					8,255
Consumer Loan [Member] | International [Member]
Finance Receivables, net [Line Items]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Outstanding Balance	445
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net	424
Post-Acquisition Finance Receivables, Carrying Value	7,352
Financing Receivable, Gross	7,776
Allowance for Notes, Loans and Financing Receivable	(14)
Notes, Loans and Financing Receivable, Net	7,762
Loans and Leases Receivable, Net Amount	$ 7,352

[1] (a)Balance at the end of the period is the sum of pre-acquisition consumer finance receivables-outstanding balance and post-acquisition consumer finance receivables, net of fees for North America Segment.