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		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Interest and Fee Income, Loans and Leases	$ 1,124	$ 1,139	$ 2,231	$ 2,274
Interest on long-term debt	(549)	(703)	(1,083)	(1,404)
Servicing asset valuation and hedge activities, net	0	(12)	0	(213)
Gain (loss) on mortgage and automotive loans, net	6	(1)	6	37
Other income, net of losses	69	74	136	231
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	(11)	2	(19)	(143)
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	(4)	(19)	(9)	48
Gain (Loss) on Derivative Instruments, Net, Pretax	(5)	(7)	(3)	(82)
Interest Gain For Qualifying Accounting Hedges Of Debt	27	28	62	61
Gains on amortization of deferred basis adjustments on the hedged items	37	38	82	76
Gain (Loss) from Revaulation of Foreign-Denominated Debt or Receivable	6	18	10	(47)
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	10	10	25	13
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	(8)	0	(6)	0
Interest on long-term debt	107	(215)	141	(313)
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	18	0	29	0
Interest on long-term debt	(107)	225	(139)	326
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	14		27
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Servicing asset valuation and hedge activities, net	0	0	0	(112)
Gain (loss) on mortgage and automotive loans, net	0	(5)	0	(37)
Other income, net of losses	(11)	7	(19)	6
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest on long-term debt	(4)	(20)	(9)	19
Other income, net of losses	$ 0	$ 1	$ 0	$ 29