Derivative Financial Instruments (Schedule Of Differences Between The Gains (Losses) On The Derivative And The Gains (Losses) On The Hedged Item) (Details) (Derivatives designed as cash flow value hedges, USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Other Comprehensive Income	$ 117	$ 1
Amount of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income	(1)	(2)
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	4	1
Interest-rate contracts
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Other Comprehensive Income	12	1
Interest-rate contracts | Net interest revenue
Derivative [Line Items]
Amount of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income	(1)	(2)
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	1	1
Foreign exchange contracts
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Other Comprehensive Income	105
Foreign exchange contracts | Net interest revenue
Derivative [Line Items]
Amount of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income	0
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	$ 3