Servicing Activities (Schedule Of Total Serviced Automobile Loans Outstanding) (Details) (Automobile Member, USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	$ 110,868	$ 111,589
On-Balance Sheet Loans [Member] | Consumer Loans Auto Financing Receivable [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	56,775	56,417
On-Balance Sheet Loans [Member] | Commercial Automobile [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	32,984	33,803
On-Balance Sheet Loans [Member] | Operating Leases [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	18,187	17,680
On-Balance Sheet Loans [Member] | Other Assets [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	48	54
Off-Balance Sheet Loans [Member] | Securitizations [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	765	887
Off-Balance Sheet Loans [Member] | Whole-Loan Transactions [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	$ 2,109	$ 2,748