Finance Receivables and Loans, Net (Troubled Debt Restructurings) (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 1,300,000,000		$ 1,200,000,000
Financing Receivable, TDRs, Number of Contracts	5,838	3,046
Financing Receivable, TDRs, Pre-Modification Recorded Investment	317,000,000	76,000,000
Financing Receivable, TDRs, Post-Modification Recorded Investment	269,000,000	74,000,000
Consumer Loans Auto Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	5,285	2,792
Financing Receivable, TDRs, Pre-Modification Recorded Investment	79,000,000	33,000,000
Financing Receivable, TDRs, Post-Modification Recorded Investment	68,000,000	33,000,000
Residential Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	545	250
Financing Receivable, TDRs, Pre-Modification Recorded Investment	169,000,000	38,000,000
Financing Receivable, TDRs, Post-Modification Recorded Investment	134,000,000	36,000,000
First Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	474	77
Financing Receivable, TDRs, Pre-Modification Recorded Investment	165,000,000	28,000,000
Financing Receivable, TDRs, Post-Modification Recorded Investment	130,000,000	27,000,000
Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	71	173
Financing Receivable, TDRs, Pre-Modification Recorded Investment	4,000,000	10,000,000
Financing Receivable, TDRs, Post-Modification Recorded Investment	4,000,000	9,000,000
Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	8	4
Financing Receivable, TDRs, Pre-Modification Recorded Investment	69,000,000	5,000,000
Financing Receivable, TDRs, Post-Modification Recorded Investment	67,000,000	5,000,000
Commercial And Industrial Automobile [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	4	3
Financing Receivable, TDRs, Pre-Modification Recorded Investment	25,000,000	3,000,000
Financing Receivable, TDRs, Post-Modification Recorded Investment	25,000,000	3,000,000
Commercial And Industrial Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	0	0
Financing Receivable, TDRs, Pre-Modification Recorded Investment	0	0
Financing Receivable, TDRs, Post-Modification Recorded Investment	0	0
Commercial And Industrial Other [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	1	0
Financing Receivable, TDRs, Pre-Modification Recorded Investment	33,000,000	0
Financing Receivable, TDRs, Post-Modification Recorded Investment	31,000,000	0
Commercial Real Estate Automobile [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	3	1
Financing Receivable, TDRs, Pre-Modification Recorded Investment	11,000,000	2,000,000
Financing Receivable, TDRs, Post-Modification Recorded Investment	11,000,000	2,000,000
Commercial Real Estate Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	0	0
Financing Receivable, TDRs, Pre-Modification Recorded Investment	0	0
Financing Receivable, TDRs, Post-Modification Recorded Investment	$ 0	$ 0