Securitizations And Variable Interest Entities (Schedule Of Variable Interest Entities) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Variable Interest Entity [Line Items]
Assets of nonconsolidated variable interest entities	$ 1,336	$ 1,495
Maximum exposure to loss in nonconsolidated VIEs	1,419	1,592
Total consoldiated involvement with VIEs	45,324	52,405
Consumer Loans Auto Financing Receivable [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	25,048	28,566
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets	0	0
Assets of nonconsolidated variable interest entities	1,336	1,495
Maximum exposure to loss in nonconsolidated VIEs	1,336	1,495
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	10	12
Commercial Automobile [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	19,576	23,139
Commercial Other [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	727	728
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets	(27)	(28)
Assets of nonconsolidated variable interest entities	0	0
Maximum exposure to loss in nonconsolidated VIEs	$ 73	$ 85