Finance Receivables Troubled Debt Restructurings (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 633		$ 633		$ 228
Troubled Debt Restructurings - Number of Loans Entering a Modification Program	11,364	4,148	27,302	6,857
Principal Collection and Recoveries on Receivables			5,099	3,050
Impaired Financing Receivable, Average Recorded Investment	552	91	417	70
Allowance Related to Finance Receivable Modifications	(88)		(88)		(32)
Financing Receivables, Modifications, Recorded Investment, Net of Allowance	545		545		196
Impaired Financing Receivable, Unpaid Principal Balance	642		642		232
Loans and Leases Receivable, Impaired, Troubled Debt, Interest Income Earne	20	3	45	4
Troubled Debt Restructurings - Amount of Loans That Entered a Loan Modification Program	$ 204	$ 77	$ 478	$ 129