Servicing Activities (Schedule Of Total Serviced Automobile Loans Outstanding) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Automobile Serviced Assets [Line Items]
Servicing fees	$ 18	$ 10	$ 31	$ 20
Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Servicing fees	18	$ 10	31	$ 20
Total Primary Serviced Assets	119,270		119,270		$ 119,808
Consumer Loan [Member] | On-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	63,113		63,113		64,067
Commercial Loan [Member] | On-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	35,251		35,251		34,895
Operating Leases [Member] | On-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	13,527		13,527		15,965
Other Assets [Member] | On-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	61		61		72
Securitizations [Member] | Off-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	3,252		3,252		2,550
Whole-Loan Transactions [Member] | Off-Balance Sheet Loans [Member] | Automobile Loan [Member]
Automobile Serviced Assets [Line Items]
Total Primary Serviced Assets	$ 4,066		$ 4,066		$ 2,259