Finance Receivables and Loans, Net (Troubled Debt Restructurings) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 1,300,000,000		$ 1,300,000,000		$ 1,300,000,000
Financing Receivable, Modifications, Number of Contracts	4,398	4,735	14,037	15,179
Financing Receivable, Modifications, Pre-Modification Recorded Investment	79,000,000	141,000,000	365,000,000	599,000,000
Financing Receivable, Modifications, Post-Modification Recorded Investment	69,000,000	128,000,000	330,000,000	520,000,000
Consumer Loans Auto Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	4,361	4,610	13,681	14,309
Financing Receivable, Modifications, Pre-Modification Recorded Investment	72,000,000	69,000,000	223,000,000	216,000,000
Financing Receivable, Modifications, Post-Modification Recorded Investment	63,000,000	57,000,000	193,000,000	182,000,000
Residential Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	37	121	350	853
Financing Receivable, Modifications, Pre-Modification Recorded Investment	7,000,000	33,000,000	71,000,000	246,000,000
Financing Receivable, Modifications, Post-Modification Recorded Investment	6,000,000	32,000,000	66,000,000	203,000,000
Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	0	4	6	17
Financing Receivable, Modifications, Pre-Modification Recorded Investment	0	39,000,000	71,000,000	137,000,000
Financing Receivable, Modifications, Post-Modification Recorded Investment	0	39,000,000	71,000,000	135,000,000
Commercial And Industrial Automobile [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	0	2	3	8
Financing Receivable, Modifications, Pre-Modification Recorded Investment	0	5,000,000	23,000,000	37,000,000
Financing Receivable, Modifications, Post-Modification Recorded Investment	0	5,000,000	23,000,000	37,000,000
Commercial And Industrial Other [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	0	1	3	4
Financing Receivable, Modifications, Pre-Modification Recorded Investment	0	27,000,000	48,000,000	80,000,000
Financing Receivable, Modifications, Post-Modification Recorded Investment	0	27,000,000	48,000,000	78,000,000
Commercial Real Estate Automobile [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	0	1	0	5
Financing Receivable, Modifications, Pre-Modification Recorded Investment	0	7,000,000	0	20,000,000
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 0	$ 7,000,000	$ 0	$ 20,000,000