Finance Receivables and Loans, Net (Troubled Debt Restructurings) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 1,300,000,000		$ 1,300,000,000		$ 1,200,000,000
Financing Receivable, TDRs, Number of Contracts	4,606	2,885	10,444	5,931
Financing Receivable, TDRs, Pre-Modification Recorded Investment	141,000,000	271,000,000	458,000,000	347,000,000
Financing Receivable, TDRs, Post-Modification Recorded Investment	123,000,000	200,000,000	392,000,000	274,000,000
Consumer Loans Auto Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	4,414	1,980	9,699	4,772
Financing Receivable, TDRs, Pre-Modification Recorded Investment	68,000,000	25,000,000	147,000,000	58,000,000
Financing Receivable, TDRs, Post-Modification Recorded Investment	57,000,000	25,000,000	125,000,000	58,000,000
Residential Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	187	899	732	1,149
Financing Receivable, TDRs, Pre-Modification Recorded Investment	44,000,000	234,000,000	213,000,000	272,000,000
Financing Receivable, TDRs, Post-Modification Recorded Investment	37,000,000	164,000,000	171,000,000	200,000,000
First Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	144	845	618	922
Financing Receivable, TDRs, Pre-Modification Recorded Investment	42,000,000	231,000,000	207,000,000	259,000,000
Financing Receivable, TDRs, Post-Modification Recorded Investment	35,000,000	161,000,000	165,000,000	188,000,000
Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	43	54	114	227
Financing Receivable, TDRs, Pre-Modification Recorded Investment	2,000,000	3,000,000	6,000,000	13,000,000
Financing Receivable, TDRs, Post-Modification Recorded Investment	2,000,000	3,000,000	6,000,000	12,000,000
Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	5	6	13	10
Financing Receivable, TDRs, Pre-Modification Recorded Investment	29,000,000	12,000,000	98,000,000	17,000,000
Financing Receivable, TDRs, Post-Modification Recorded Investment	29,000,000	11,000,000	96,000,000	16,000,000
Commercial And Industrial Automobile [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	2	3	6	6
Financing Receivable, TDRs, Pre-Modification Recorded Investment	7,000,000	5,000,000	32,000,000	8,000,000
Financing Receivable, TDRs, Post-Modification Recorded Investment	7,000,000	5,000,000	32,000,000	8,000,000
Commercial And Industrial Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	0	0	0	0
Financing Receivable, TDRs, Pre-Modification Recorded Investment	0	0	0	0
Financing Receivable, TDRs, Post-Modification Recorded Investment	0	0	0	0
Commercial And Industrial Other [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	2	0	3	0
Financing Receivable, TDRs, Pre-Modification Recorded Investment	20,000,000	0	53,000,000	0
Financing Receivable, TDRs, Post-Modification Recorded Investment	20,000,000	0	51,000,000	0
Commercial Real Estate Automobile [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	1	3	4	4
Financing Receivable, TDRs, Pre-Modification Recorded Investment	2,000,000	7,000,000	13,000,000	9,000,000
Financing Receivable, TDRs, Post-Modification Recorded Investment	2,000,000	6,000,000	13,000,000	8,000,000
Commercial Real Estate Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts	0	0	0	0
Financing Receivable, TDRs, Pre-Modification Recorded Investment	0	0	0	0
Financing Receivable, TDRs, Post-Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0