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, 2013	Mar. 31, 2012
Financing Receivable, Impaired [Line Items]
Average balance	$ 1,403	$ 1,010
Impaired Financing Receivable, Interest Income, Accrual Method	14	9
Consumer Loans Auto Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Average balance	272	83
Impaired Financing Receivable, Interest Income, Accrual Method	4	2
Residential Mortgage [Member]
Financing Receivable, Impaired [Line Items]
Average balance	879	612
Impaired Financing Receivable, Interest Income, Accrual Method	8	5
First Mortgage [Member]
Financing Receivable, Impaired [Line Items]
Average balance	744	512
Impaired Financing Receivable, Interest Income, Accrual Method	7	4
Home Equity [Member]
Financing Receivable, Impaired [Line Items]
Average balance	135	100
Impaired Financing Receivable, Interest Income, Accrual Method	1	1
Commercial Loan [Member]
Financing Receivable, Impaired [Line Items]
Average balance	252	315
Impaired Financing Receivable, Interest Income, Accrual Method	2	2
Commercial And Industrial Automobile [Member]
Financing Receivable, Impaired [Line Items]
Average balance	157	196
Impaired Financing Receivable, Interest Income, Accrual Method	2	2
Commercial And Industrial Mortgage [Member]
Financing Receivable, Impaired [Line Items]
Average balance	0	7
Impaired Financing Receivable, Interest Income, Accrual Method	0	0
Commercial And Industrial Other [Member]
Financing Receivable, Impaired [Line Items]
Average balance	57	34
Impaired Financing Receivable, Interest Income, Accrual Method	0	0
Commercial Real Estate Automobile [Member]
Financing Receivable, Impaired [Line Items]
Average balance	38	63
Impaired Financing Receivable, Interest Income, Accrual Method	0	0
Commercial Real Estate Mortgage [Member]
Financing Receivable, Impaired [Line Items]
Average balance	0	15
Impaired Financing Receivable, Interest Income, Accrual Method	$ 0	$ 0