Securitizations And Variable Interest Entities (Schedule Of Quantitative Information about Securitized and Other Financial Assets Managed Together) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
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	$ 260,226	$ 484,248
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	2,519	27,418
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	129,212	326,975
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	1,848	20,757
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	121,913	123,312
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	640	3,760
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	9,101	33,961
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	31	2,901
Consumer Loans Auto Financing Receivable [Member] | 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	1,829	0
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	1	0
Consumer Loans Auto Financing Receivable [Member] | 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	68,759	63,884
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	342	341
Commercial Automobile [Member] | 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	38,373	37,302
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	67	162
Commercial Finance Receivables And Loans, Mortgage [Member] | 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	1,146	1,925
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	0	14
Commercial Other [Member] | 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	2,435	1,261
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	1	1
Residential Mortgage [Member] | 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	11,200	18,940
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	230	3,242
US Government-sponsored Enterprises [Member]
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
loans subject to conditional repurchase options	0	2,300
US Government-sponsored Enterprises [Member] | 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	127,383	262,984
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	1,847	9,456
Private Placement [Member]
Quantitative Information about Securitized and Other Financial Assets Managed Together [Line Items]
loans subject to conditional repurchase options	0	132
Private Placement [Member] | 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	0	63,991
Delinquent Amount at End of Period on Loans Managed and Securitized or Asset-backed Financing Arrangement	$ 0	$ 11,301