Derivative Financial Instruments (Impact Of Derivatives On Consolidated Statement Of Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Derivatives Not Designated As Hedging Instruments [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	$ 115	$ 218	$ 372	$ 528
Derivatives Designated As Fair Value Hedges [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	47	(433)	85	(407)
Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income	(46)	436	(85)	408
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				(56)
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				158
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				306
Interest Rate Contracts [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Processing Fees And Other Revenue [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	0	0	2	0
Interest Rate Contracts [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Trading Services Revenue [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	1	43	(87)	(4)
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	(21)	(42)	(58)
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	1	172	3
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	22	44	62	60
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	(1)	(171)	(7)	(161)
Foreign Exchange Contracts [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	2		2
Foreign Exchange Contracts [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Processing Fees And Other Revenue [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	1	5	(2)	6
Foreign Exchange Contracts [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Trading Services Revenue [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	113	170	459	526
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	(26)	306	(30)
Foreign Exchange 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		(306)		(306)
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	$ 26		$ 30