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		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Interest and Fee Income, Loans and Leases	$ 1,114	$ 1,119	$ 3,345	$ 3,393
Interest on long-term debt	(493)	(609)	(1,576)	(2,013)
Servicing asset valuation and hedge activities, net	0	0	0	(213)
Gain (loss) on mortgage and automotive loans, net	0	15	6	52
Other income, net of losses	78	93	214	324
Gain (Loss) on Equity Forward Contract Not Designated as Hedging Instruments	(6)	0	(6)	0
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	(5)	20	(24)	(123)
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	(100)	48	(109)	96
Gain (Loss) on Derivative Instruments, Net, Pretax	(88)	64	(91)	(18)
Interest Gain For Qualifying Accounting Hedges Of Debt	27	33	89	94
Gains on amortization of deferred basis adjustments on the hedged items	38	112	120	188
Gain (Loss) from Revaulation of Foreign-Denominated Debt or Receivable	102	(47)	112	(94)
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	23	(4)	48	9
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	28	3	22	3
Interest on long-term debt	(39)	11	102	(302)
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	(15)	(3)	14	(3)
Interest on long-term debt	49	(15)	(90)	311
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	16	1	43	1
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	0	0	(37)
Other income, net of losses	(5)	20	(24)	26
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest on long-term debt	(108)	52	(117)	71
Other income, net of losses	8	(4)	8	25
Forward Contracts [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other income, net of losses	$ (6)	$ 0	$ (6)	$ 0