Transfers of Receivables - Derivative Income and Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Derivative expense/(income) related to securitization transactions [Abstract]
Derivative expense/(income)	$ (481)	$ (512)	$ (106)
Securitization Transactions [Member]
Derivative expense/(income) related to securitization transactions [Abstract]
Derivative expense/(income)	(2)	(4)	25
Related to Variable Interest Entity - Not VIE [Member] | Securitization Transactions [Member]
Derivative expense/(income) related to securitization transactions [Abstract]
Derivative expense/(income)	12	(16)	16
Other, Not Variable Interest Entity Related [Member] | Securitization Transactions [Member]
Derivative expense/(income) related to securitization transactions [Abstract]
Derivative expense/(income)	18	21	6
Variable Interest Entity, Primary Beneficiary [Member] | Securitization Transactions [Member]
Derivative expense/(income) related to securitization transactions [Abstract]
Derivative expense/(income)	$ (32)	$ (9)	$ 3