Transfers of Receivables - Exposure Based on Fair Value of Derivative Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Securitization Transactions [Line Items]
Fair Value of Derivative Assets	$ 924	$ 859
Fair Value of Derivative Liabilities	243	167
Securitization Transactions [Member]
Securitization Transactions [Line Items]
Fair Value of Derivative Assets	116	48
Fair Value of Derivative Liabilities	48	30
Related to Variable Interest Entity - Not VIE [Member] | Securitization Transactions [Member]
Securitization Transactions [Line Items]
Fair Value of Derivative Assets	19	16
Fair Value of Derivative Liabilities	29	7
Other, Not Variable Interest Entity Related [Member] | Securitization Transactions [Member]
Securitization Transactions [Line Items]
Fair Value of Derivative Assets	12	5
Fair Value of Derivative Liabilities	0	1
Variable Interest Entity, Primary Beneficiary [Member]
Securitization Transactions [Line Items]
Fair Value of Derivative Assets	85	27
Fair Value of Derivative Liabilities	19	22
Variable Interest Entity, Primary Beneficiary [Member] | Securitization Transactions [Member]
Securitization Transactions [Line Items]
Fair Value of Derivative Assets	85	27
Fair Value of Derivative Liabilities	$ 19	$ 22