Securitizations And Variable Interest Entities (Schedule Of Variable Interest Entities) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010
Variable Interest Entity [Line Items]
Assets of nonconsolidated variable interest entities	$ 1,659		$ 51,757
Maximum exposure to loss in nonconsolidated VIEs	1,764		48,860
Total consoldiated involvement with VIEs	48,500		51,094
Mortgage loans held-for-sale	1,927		8,112
Other assets	13,936		18,741
Mortgage servicing rights	902	1,105	2,519	2,663	3,701		3,738
Excess Servicing Rights Sold to Variable Interest Entity						266
Total finance receivables and loans, net	119,836		113,252
Consumer Loans Auto Financing Receivable [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	29,131		26,504
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets	0
Assets of nonconsolidated variable interest entities	1,659
Maximum exposure to loss in nonconsolidated VIEs	1,659
Commercial Automobile [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	18,741		19,594
Other [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets			956
Consumer Mortgage Other Member
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets	0		0
Assets of nonconsolidated variable interest entities	0		0
Maximum exposure to loss in nonconsolidated VIEs	13		17
Government National Mortgage Association (GNMA) [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets			2,652
Assets of nonconsolidated variable interest entities			44,127
Maximum exposure to loss in nonconsolidated VIEs			44,127
Canada Mortgage and Housing Corporation [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets			66
Assets of nonconsolidated variable interest entities			3,222
Maximum exposure to loss in nonconsolidated VIEs			66
Private Placement [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets			1,098
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets			141
Assets of nonconsolidated variable interest entities			4,408
Maximum exposure to loss in nonconsolidated VIEs			4,408
Commercial Other [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	656
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets	(28)		83
Assets of nonconsolidated variable interest entities	0		0
Maximum exposure to loss in nonconsolidated VIEs	92		242
Other assets	0		20
Total finance receivables and loans, net	0		100
Accrued expenses and other liabilities	28		37
Off Balance Sheet Variable Interest Entities Member | Residential Mortgage [Member]
Variable Interest Entity [Line Items]
Mortgage loans held-for-sale	0		2,400
Other assets	0		92
Mortgage servicing rights	$ 0		$ 386