Securitizations And Variable Interest Entities (Schedule Of Quantitative Information and Net Credit Losses about Securitized and Other Financial Assets Managed Together) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	$ 102,631		$ 104,110
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	556		690
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	136	115
On-Balance Sheet Loans [Member]
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	99,667		100,363
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	501		618
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	133	114
On-Balance Sheet Loans [Member] | Consumer Loans Auto Financing Receivable [Member]
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	56,775		56,417
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	301		412
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	121	93
On-Balance Sheet Loans [Member] | Residential Mortgage [Member]
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	8,181		8,460
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	146		164
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	12	21
On-Balance Sheet Loans [Member] | Commercial Automobile [Member]
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	32,984		33,803
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	54		42
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	0	1
On-Balance Sheet Loans [Member] | Commercial Other [Member]
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	1,727		1,683
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	0		0
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	0	(1)
Off-Balance Sheet Loans [Member]
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	776		899
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	3		3
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	0	1
Off-Balance Sheet Loans [Member] | Consumer Loans Auto Financing Receivable [Member]
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	776		899
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	3		3
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	0	1
Whole-Loan Transactions [Member]
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement	2,188		2,848
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	52		69
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	$ 3