Investment Securities (Schedule Of Realized Gross Gains And Losses On Sale From Available For Sale Portfolio ) (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010
Gross gains on sales of securities	$ 35,162,000	[1]	$ 35,000	[1]	$ 44,585,000	[1]	$ 231,000	[1]
Gross (losses) on sales of securities					(8,623,000)		(1,000)
Net gain/(loss) on sales of securities	35,162,000	[2]	35,000	[2]	35,962,000	[2]	230,000	[2]
Venture capital investments			(2,963,000)	[3]			(4,801,000)	[3]
Net other than temporary impairment ("OTTI") recorded							(188,000)	[4]
Total securities gain/(loss)	35,162,000		(2,928,000)		35,962,000		(4,759,000)
Proceeds from sales from available for sale portfolio	35,200,000		0		500,000		36,500,000
Visa Class B Shares [Member]
Gross gains on sales of securities	$ 35,100,000				$ 35,100,000

[1] Three and nine months ended September 30, 2011, include gain of $35.1 million related to the sale of Visa Class B shares.

[2] Proceeds from sales for the three months ended September 30, 2011, were $35.2 million. Proceeds were not material in third quarter 2010. Proceeds were $.5 billion and $36.5 million for the nine months ended September 30, 2011 and 2010, respectively.

[3] Generally includes write-offs and/or fair value adjustments related to venture capital investments.

[4] OTTI recognized for the nine months ended September 30, 2010 is related to marketable equity securities.