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, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Derivative expense/(income) related to securitization transactions [Abstract]
Derivative expense/(income)	$ 70	$ (60)	$ 218	$ 19
Variable Interest Entity, Primary Beneficiary [Member]
Derivative expense/(income) related to securitization transactions [Abstract]
Derivative expense/(income)	58	(46)	209	(13)
Related to Variable Interest Entity - Not VIE [Member]
Derivative expense/(income) related to securitization transactions [Abstract]
Derivative expense/(income)	8	(18)	(7)	20
Other, Not Variable Interest Entity Related [Member]
Derivative expense/(income) related to securitization transactions [Abstract]
Derivative expense/(income)	$ 4	$ 4	$ 16	$ 12