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		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Derivatives Designated as Cash Flow Value Hedges [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Other Comprehensive Income	$ 3	$ 4	$ 4	$ 4
Amount of Gain (Loss) Reclassified from OCI to Consolidated Statement of Income	(1)	(2)	(3)	(4)
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income	0	1	1	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)	(2)	(3)	(4)
Amount of Gain (Loss) on Derivative Recognized in Consolidated Statement of Income		1	1	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	2	4	3	4
Foreign Exchange Contracts [Member]
Derivative [Line Items]
Amount of Gain (Loss) on Derivative Recognized in Other Comprehensive Income	1		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			$ 0