Transfers of Receivables - Derivative Income and Expense (Details) (Securitization Transactions [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Derivative expense/(income) related to securitization transactions [Abstract]
Derivative expense/(income)	$ 78	$ 70	$ (6)	$ 218
Variable Interest Entity, Primary Beneficiary [Member]
Derivative expense/(income) related to securitization transactions [Abstract]
Derivative expense/(income)	73	58	(20)	209
Related to Variable Interest Entity - Not VIE [Member]
Derivative expense/(income) related to securitization transactions [Abstract]
Derivative expense/(income)	(2)	8	8	(7)
Other, Not Variable Interest Entity Related [Member]
Derivative expense/(income) related to securitization transactions [Abstract]
Derivative expense/(income)	$ 7	$ 4	$ 6	$ 16