Transfers of Receivables - Exposure Based on Fair Value of Derivative Instruments (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Securitization Transactions [Line Items]
Fair Value of Derivative Assets	$ 668	$ 585
Fair Value of Derivative Liabilities	470	506
Variable Interest Entity, Primary Beneficiary [Member]
Securitization Transactions [Line Items]
Fair Value of Derivative Assets	1	5
Fair Value of Derivative Liabilities	73	88
Securitization Transactions [Member]
Securitization Transactions [Line Items]
Fair Value of Derivative Assets	25	33
Fair Value of Derivative Liabilities	98	125
Securitization Transactions [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Securitization Transactions [Line Items]
Fair Value of Derivative Assets	1	5
Fair Value of Derivative Liabilities	73	88
Related to Variable Interest Entity - Not VIE [Member] | Securitization Transactions [Member]
Securitization Transactions [Line Items]
Fair Value of Derivative Assets	19	23
Fair Value of Derivative Liabilities	19	30
Other, Not Variable Interest Entity Related [Member] | Securitization Transactions [Member]
Securitization Transactions [Line Items]
Fair Value of Derivative Assets	5	5
Fair Value of Derivative Liabilities	$ 6	$ 7