Derivative Financial Instruments (Impact of Derivatives on Consolidated Statement of Income) (Details) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Interest-Rate Contracts [Member] | Long-Term Debt [Member] | Derivatives Designated as Fair Value Hedges [Member] | Processing Fees and Other Revenue [Member]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income		$ 38		$ 40
Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income		(36)		(35)
Interest-Rate Contracts [Member] | Derivatives Designated as Fair Value Hedges [Member] | Processing Fees and Other Revenue [Member]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	19		16
Interest-Rate Contracts [Member] | Derivatives Designated as Fair Value Hedges [Member] | Processing Fees and Other Revenue [Member] | Total Investment Securities Available for Sale [Member]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	(16)	(81)	10	(90)
Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income	11	81	(14)	90
Interest-Rate Contracts [Member] | Derivatives not Designated as Hedging Instruments [Member] | Processing Fees and Other Revenue [Member]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income		3		14
Interest-Rate Contracts [Member] | Derivatives not Designated as Hedging Instruments [Member] | Trading Services Revenue [Member]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	(8)	(1)	(18)	(2)
Foreign Exchange Contracts [Member] | Derivatives not Designated as Hedging Instruments [Member] | Processing Fees and Other Revenue [Member]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	(4)	(5)	1	(7)
Foreign Exchange Contracts [Member] | Derivatives not Designated as Hedging Instruments [Member] | Trading Services Revenue [Member]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	168	188	327	331
Long-Term Debt [Member] | Derivatives Designated as Fair Value Hedges [Member] | Processing Fees and Other Revenue [Member]
Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income	(17)		(14)
Derivatives Designated as Fair Value Hedges [Member]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	3	(43)	26	(50)
Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income	(6)	45	(28)	55
Derivatives not Designated as Hedging Instruments [Member]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	$ 156	$ 185	$ 310	$ 336