Derivative Instruments And Hedging Activities (Statement Of Gains and Losses on Derivative Instruments Reported in Statement of Comprehensive Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Interest and Fee Income, Loans and Leases	$ 1,107	$ 1,135
Interest on long-term debt	(534)	(701)
Servicing asset valuation and hedge activities, net	0	(201)
Gain (loss) on mortgage and automotive loans, net	0	38
Other income, net of losses	67	157
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	(8)	(145)
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	(5)	67
Gain (Loss) on Derivative Instruments, Net, Pretax	2	(75)
Interest Gain For Qualifying Accounting Hedges Of Debt	35	33
Gains on amortization of deferred basis adjustments on the hedged items	45	38
Gain (Loss) from Revaulation of Foreign-Denominated Debt or Receivable	4	(65)
Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	15	3
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Gain (Loss) Recognized in Earnings on Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest and Fee Income, Loans and Leases	2	0
Interest on long-term debt	34	(98)
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Gain (Loss) Recognized in Earnings on Hedged Item [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest and Fee Income, Loans and Leases	11	0
Interest on long-term debt	(32)	101
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Gain (loss) Excluded from Earnings on Derivatives [Domain]
Derivative Instruments, Gain (Loss) [Line Items]
Interest and Fee Income, Loans and Leases	(13)
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Servicing asset valuation and hedge activities, net	0	(112)
Gain (loss) on mortgage and automotive loans, net	0	(32)
Other income, net of losses	(8)	(1)
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest on long-term debt	(5)	39
Other income, net of losses	$ 0	$ 28