Transfers of Receivables - Derivative Income and Expense (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Derivative expense/(income) related to securitization transactions [Abstract]
Derivative expense/(income)	$ (205)	$ (46)
Securitization Transactions [Member]
Derivative expense/(income) related to securitization transactions [Abstract]
Derivative expense/(income)	(16)	18
Securitization Transactions [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Derivative expense/(income) related to securitization transactions [Abstract]
Derivative expense/(income)	(24)	20
Related to Variable Interest Entity - Not VIE [Member] | Securitization Transactions [Member]
Derivative expense/(income) related to securitization transactions [Abstract]
Derivative expense/(income)	(5)	(6)
Other, Not Variable Interest Entity Related [Member] | Securitization Transactions [Member]
Derivative expense/(income) related to securitization transactions [Abstract]
Derivative expense/(income)	$ 13	$ 4