Servicing Activities (Schedule Of Total Serviced Automobile Loans Outstanding) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Automobile Serviced Assets [Line Items]
Servicing fees	$ 12	$ 6	$ 32	$ 22
Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Servicing fees	12	$ 6	32	$ 22
Total Primary Serviced Assets	117,618		117,618		$ 115,391
Consumer Loan [Member] | On-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	63,352		63,352		58,085
Commercial Loan [Member] | On-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	32,322		32,322		34,022
Operating Leases [Member] | On-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	16,955		16,955		19,510
Other Assets [Member] | On-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	61		61		55
Securitizations [Member] | Off-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	2,901		2,901		2,832
Whole-Loan Transactions [Member] | Off-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	$ 2,027		$ 2,027		$ 887