Securitizations And Variable Interest Entities (Schedule Of Cash Flow Received and Paid To Nonconsolidated Securitization Entities) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Private Placement [Member]
Cash Flow Received and Paid to Nonconsolidated Securitization Entities [Line Items]
Cash Flows Between Transferor and Transferee, Proceeds from New Transfers	$ 0	$ 727
Cash flows received on retained interests in securitization entities	71	37
Cash Flows Between Transferor and Transferee, Servicing Fees	63	72
Purchases of previously transferred financial assets	(12)	(11)
Representations and warranties obligations	(7)	(28)
Cash Flows Between Transferor and Transferee, Receipts on Transferor's Interest in Transferred Financial Assets, Other	255	141
US Government-sponsored Enterprises [Member]
Cash Flow Received and Paid to Nonconsolidated Securitization Entities [Line Items]
Cash Flows Between Transferor and Transferee, Proceeds from New Transfers	16,645	28,418
Cash flows received on retained interests in securitization entities	0	0
Cash Flows Between Transferor and Transferee, Servicing Fees	434	495
Purchases of previously transferred financial assets	(876)	(1,068)
Representations and warranties obligations	(30)	(100)
Cash Flows Between Transferor and Transferee, Receipts on Transferor's Interest in Transferred Financial Assets, Other	(84)	67
Consumer Loans Auto Financing Receivable [Member]
Cash Flow Received and Paid to Nonconsolidated Securitization Entities [Line Items]
Cash Flows Between Transferor and Transferee, Proceeds from New Transfers	$ 1,978	$ 0