Derivative Financial Instruments (Impact Of Derivatives On Consolidated Statement Of Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	$ 1	$ 1
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	129	154
Derivatives Designated As Fair Value Hedges [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	39	23
Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income	(44)	(22)
Interest-Rate Contracts [Member] | Not Designated as Hedging Instrument [Member] | Processing Fees And Other Revenue [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	2	0
Interest-Rate Contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Services Revenue [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	(88)	(10)
Interest-Rate Contracts [Member] | Derivatives Designated As Fair Value Hedges [Member] | Processing Fees And Other Revenue [Member] | Long-Term Debt [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income	13	3
Interest-Rate Contracts [Member] | Derivatives Designated As Fair Value Hedges [Member] | Processing Fees And Other Revenue [Member] | Investment Securities Available For Sale [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income	(27)	(25)
Interest-Rate Contracts [Member] | Derivatives Designated As Fair Value Hedges [Member] | Processing Fees And Other Revenue [Member] | Contract One [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	(16)	(3)
Interest-Rate Contracts [Member] | Derivatives Designated As Fair Value Hedges [Member] | Processing Fees And Other Revenue [Member] | Contract Two [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	25	26
Foreign Exchange Contracts [Member] | Not Designated as Hedging Instrument [Member] | Processing Fees And Other Revenue [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	(2)	5
Foreign Exchange Contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Services Revenue [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	217	159
Foreign Exchange Contracts [Member] | Derivatives Designated As Fair Value Hedges [Member] | Processing Fees And Other Revenue [Member] | Investment Securities [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income	(30)
Foreign Exchange Contracts [Member] | Derivatives Designated As Fair Value Hedges [Member] | Processing Fees And Other Revenue [Member] | Contract Three [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	$ 30