Finance Receivables And Loans, Net (Average Balance And Interest Income Of Impaired Finance Receivables) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	$ 679	$ 1,411
Impaired Financing Receivable, Interest Income, Accrual Method	9	13
Consumer Loans Auto Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	290	294
Impaired Financing Receivable, Interest Income, Accrual Method	4	4
Residential Mortgage [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	311	928
Impaired Financing Receivable, Interest Income, Accrual Method	2	8
Commercial Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	78	189
Impaired Financing Receivable, Interest Income, Accrual Method	3	1
Commercial And Industrial Automobile [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	34	104
Impaired Financing Receivable, Interest Income, Accrual Method	0	1
Commercial And Industrial Other [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	40	74
Impaired Financing Receivable, Interest Income, Accrual Method	3	0
Commercial Real Estate Automobile [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	4	11
Impaired Financing Receivable, Interest Income, Accrual Method	$ 0	$ 0