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, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Interest on long-term debt	$ 1,068	$ 1,331	$ 2,245	$ 2,737
Servicing asset valuation and hedge activities, net	(73)	(105)	(64)	(192)
Gain (loss) on mortgage and automotive loans, net	134	116	260	206
Other gain (loss) on investments, net	66	92	156	176
Other income, net of losses	226	239	503	443
Other operating expenses	1,933	892	2,649	1,638
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	215	(100)	180	(331)
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	45	20	15	(72)
Gain (Loss) on Derivative Instruments, Net, Pretax	270	(72)	186	(397)
Interest Gain For Qualifying Accounting Hedges Of Debt	30	82	59	170
Gains on amortization of deferred basis adjustments on the hedged items	61	53	124	117
Gain (Loss) from Revaulation of Foreign-Denominated Debt or Receivable	(55)	(33)	(26)	57
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	8	(9)	6
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Gain (Loss) Recognized in Earnings on Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest on long-term debt	267	262	196	114
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 on long-term debt	(257)	(254)	(205)	(108)
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest on long-term debt	(1)	0	(3)	0
Servicing asset valuation and hedge activities, net	329	127	337	(77)
Gain (loss) on mortgage and automotive loans, net	(67)	(190)	(124)	(230)
Other gain (loss) on investments, net	0	0	0	1
Other income, net of losses	(46)	(41)	(30)	(33)
Other operating expenses	0	4	0	8
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest on long-term debt	(1)	48	(12)	61
Other income, net of losses	50	(28)	25	(133)
Other operating expenses	$ (4)	$ 0	$ 2	$ 0