Servicing Activities (Schedule Of Total Serviced Automobile Loans Outstanding) (Details) (Automobile Member, USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	$ 128,980	$ 122,881
On-Balance Sheet Loans [Member] | Consumer Loans Auto Financing Receivable [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	68,759	63,884
On-Balance Sheet Loans [Member] | Commercial Automobile [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	38,373	37,302
On-Balance Sheet Loans [Member] | Operating Leases [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	11,197	9,275
On-Balance Sheet Loans [Member] | Operations Held-For-Sale [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	43	102
Off-Balance Sheet Loans [Member] | Securitizations [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	1,803	0
Off-Balance Sheet Loans [Member] | Whole-Loan Transactions [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	$ 8,805	$ 12,318