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		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 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	$ 102,791		$ 102,791		$ 104,110
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	609		609		690
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	150	130	373	354
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	99,521		99,521		100,363
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	569		569		618
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	149	126	367	343
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	58,675		58,675		56,417
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	388		388		412
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	137	115	341	288
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	7,598		7,598		8,460
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	181		181		164
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	12	11	32	58
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	31,492		31,492		33,803
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	0		0		42
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	0	0	1	0
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	1,756		1,756		1,683
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	0		0		0
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	0	0	(7)	(3)
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	2,032		2,032		899
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	3		3		3
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	0	1	1	3
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	2,032		2,032		899
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	3		3		3
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	0	1	1	3
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	1,238		1,238		2,848
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	37		37		69
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	$ 1	$ 3	$ 5	$ 8