Derivative Financial Instruments (Schedule Of Differences Between The Gains (Losses) On The Derivative And The Gains (Losses) On The Hedged Item) (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 Designated as Cash Flow Value Hedges [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Other Comprehensive Income	$ (2)	$ 4	$ 2	$ 8
Amount of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income	(1)	(1)	(4)	(5)
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	3	0	4	2
Net Interest Revenue [Member] | Derivatives Designated as Cash Flow Value Hedges [Member]
Derivative [Line Items]
Amount of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income	(1)	(1)	(4)	(5)
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	1		2	2
Interest Rate Contracts [Member] | Derivatives Designated as Cash Flow Value Hedges [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Other Comprehensive Income		4	3	8
Foreign Exchange Contracts [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Other Comprehensive Income	(2)		(1)
Amount of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income	0		0
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	$ 2		$ 2