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 [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Other Comprehensive Income	$ 126	$ 9	$ 7
Amount of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income	(5)	(7)	(7)
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	9	3	5
Interest rate contracts [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Other Comprehensive Income	4	9	7
Interest rate contracts [Member] | Net Interest Revenue [Member]
Derivative [Line Items]
Amount of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income	(5)	(7)	(7)
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	3	3	5
Foreign exchange contracts [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Other Comprehensive Income	122	0	0
Foreign exchange contracts [Member] | Net Interest Revenue [Member]
Derivative [Line Items]
Amount of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income	0	0	0
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	$ 6	$ 0	$ 0