Securitizations And Variable Interest Entities (Schedule Of Cash Flow Received and Paid To Nonconsolidated Securitization Entities) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 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	$ 5	$ 722
Cash flows received on retained interests in securitization entities	71	53
Cash Flows Between Transferor and Transferee, Servicing Fees	63	152
Purchases of previously transferred financial assets	(12)	(17)
Representations and warranties obligations	(7)	(29)
Cash Flows Between Transferor and Transferee, Receipts on Transferor's Interest in Transferred Financial Assets, Other	255	135
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	23,779	43,877
Cash flows received on retained interests in securitization entities	0	0
Cash Flows Between Transferor and Transferee, Servicing Fees	560	747
Purchases of previously transferred financial assets	(876)	(1,744)
Representations and warranties obligations	(105)	(101)
Cash Flows Between Transferor and Transferee, Receipts on Transferor's Interest in Transferred Financial Assets, Other	(91)	60
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
Cash Flows Between Transferor and Transferee, Servicing Fees	$ 8	$ 0