Finance Receivables and Loans, Net (Troubled Debt Restructurings) (Details) (USD $)	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	$ 1,300,000,000		$ 1,300,000,000		$ 1,200,000,000
Financing Receivable, Modifications, Number of Contracts	4,735	1,514	15,179	7,445
Financing Receivable, Modifications, Pre-Modification Recorded Investment	141,000,000	102,000,000	599,000,000	449,000,000
Financing Receivable, Modifications, Post-Modification Recorded Investment	128,000,000	87,000,000	520,000,000	361,000,000
Consumer Loans Auto Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	4,610	1,207	14,309	5,979
Financing Receivable, Modifications, Pre-Modification Recorded Investment	69,000,000	14,000,000	216,000,000	72,000,000
Financing Receivable, Modifications, Post-Modification Recorded Investment	57,000,000	14,000,000	182,000,000	72,000,000
Residential Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	121	303	853	1,452
Financing Receivable, Modifications, Pre-Modification Recorded Investment	33,000,000	79,000,000	246,000,000	351,000,000
Financing Receivable, Modifications, Post-Modification Recorded Investment	32,000,000	64,000,000	203,000,000	264,000,000
First Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	88	218	706	1,140
Financing Receivable, Modifications, Pre-Modification Recorded Investment	31,000,000	74,000,000	238,000,000	333,000,000
Financing Receivable, Modifications, Post-Modification Recorded Investment	31,000,000	59,000,000	196,000,000	247,000,000
Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	33	85	147	312
Financing Receivable, Modifications, Pre-Modification Recorded Investment	2,000,000	5,000,000	8,000,000	18,000,000
Financing Receivable, Modifications, Post-Modification Recorded Investment	1,000,000	5,000,000	7,000,000	17,000,000
Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	4	4	17	14
Financing Receivable, Modifications, Pre-Modification Recorded Investment	39,000,000	9,000,000	137,000,000	26,000,000
Financing Receivable, Modifications, Post-Modification Recorded Investment	39,000,000	9,000,000	135,000,000	25,000,000
Commercial And Industrial Automobile [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	2	3	8	9
Financing Receivable, Modifications, Pre-Modification Recorded Investment	5,000,000	7,000,000	37,000,000	15,000,000
Financing Receivable, Modifications, Post-Modification Recorded Investment	5,000,000	7,000,000	37,000,000	15,000,000
Commercial And Industrial Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	0	0	0	0
Financing Receivable, Modifications, Pre-Modification Recorded Investment	0	0	0	0
Financing Receivable, Modifications, Post-Modification Recorded Investment	0	0	0	0
Commercial And Industrial Other [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	1	0	4	0
Financing Receivable, Modifications, Pre-Modification Recorded Investment	27,000,000	0	80,000,000	0
Financing Receivable, Modifications, Post-Modification Recorded Investment	27,000,000	0	78,000,000	0
Commercial Real Estate Automobile [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	1	1	5	5
Financing Receivable, Modifications, Pre-Modification Recorded Investment	7,000,000	2,000,000	20,000,000	11,000,000
Financing Receivable, Modifications, Post-Modification Recorded Investment	7,000,000	2,000,000	20,000,000	10,000,000
Commercial Real Estate Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	0	0	0	0
Financing Receivable, Modifications, Pre-Modification Recorded Investment	0	0	0	0
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0