Derivative Financial Instruments (Impact of Derivatives on Consolidated Statement of Income) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Derivatives not designated as hedging instruments
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	$ 589	$ 494	$ 669
Derivatives designated as fair value hedges
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	(343)	95	(251)
Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income	328	(96)	244
Foreign exchange contracts | Trading services | Derivatives not designated as hedging instruments
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	586	576	641
Foreign exchange contracts | Processing fees and other revenue | Derivatives not designated as hedging instruments
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	0	(2)	7
Foreign exchange contracts | Processing fees and other revenue | Derivatives designated as fair value hedges
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	(183)	34	(161)
Foreign exchange contracts | Processing fees and other revenue | Investment securities | Derivatives designated as fair value hedges
Derivative [Line Items]
Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income	183	(34)	161
Interest-rate contracts | Trading services | Derivatives not designated as hedging instruments
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	2	(86)	21
Interest-rate contracts | Processing fees and other revenue | Derivatives not designated as hedging instruments
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	0	6	0
Interest-rate contracts | Processing fees and other revenue | Contract one | Derivatives designated as fair value hedges
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	32	11	(165)
Interest-rate contracts | Processing fees and other revenue | Contract two | Derivatives designated as fair value hedges
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	(192)	50	75
Interest-rate contracts | Processing fees and other revenue | Long-term debt | Derivatives designated as fair value hedges
Derivative [Line Items]
Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income	(30)	(17)	153
Interest-rate contracts | Processing fees and other revenue | Investment securities available for sale | Derivatives designated as fair value hedges
Derivative [Line Items]
Amount of Gain (Loss) on Hedged Item Recognized in Consolidated Statement of Income	175	(45)	(70)
Credit derivative contracts | Processing fees and other revenue | Derivatives not designated as hedging instruments
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	$ 1	$ 0	$ 0