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		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 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	$ 103,088		$ 103,088		$ 104,110
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	547		547		690
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	86	109	223	224
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	100,781		100,781		100,363
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	500		500		618
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	85	103	218	217
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	58,114		58,114		56,417
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	345		345		412
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	83	80	204	173
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	7,850		7,850		8,460
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	142		142		164
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	8	26	20	47
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	33,041		33,041		33,803
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	13		13		42
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	1	(1)	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	1,776		1,776		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	(7)	(2)	(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	659		659		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	2
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	659		659		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	2
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	1,648		1,648		2,848
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	44		44		69
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	$ 1	$ 5	$ 4	$ 5