Servicing Activities (Schedule Of Total Serviced Automobile Loans Outstanding) (Details) - Automobile Member - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	$ 116,761	$ 115,391
On-Balance Sheet Loans [Member] | Consumer Loans Auto Financing Receivable [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	62,142	58,085
On-Balance Sheet Loans [Member] | Commercial Automobile [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	33,026	34,022
On-Balance Sheet Loans [Member] | Operating Leases [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	17,950	19,510
On-Balance Sheet Loans [Member] | Other Assets [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	61	55
Off-Balance Sheet Loans [Member] | Securitizations [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	2,234	2,832
Off-Balance Sheet Loans [Member] | Whole-Loan Transactions [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	$ 1,348	$ 887