Loans And Allowance For Loan Losses (Narrative) (Details) (USD $)	Mar. 31, 2012	Dec. 31, 2011
Loans And Allowance For Loan Losses [Abstract]
Loans pledged at the Federal Home Loan Bank as collateral for borrowings and letters of credit obtained to secure public deposits	$ 3,100,000,000
Loans pledged at the Federal Reserve Bank as collateral for discount window borrowings	1,200,000,000
Restructured loans performing under their modified terms	41,300,000	41,300,000
Aggregate restructured credit card loans held	22,500,000	22,400,000
Personal real estate loans excluded from table	221,000,000
Consumer loans excluded from table	140,200,000
Consumer and personal real estate loans excluded from table, as a percentage of Personal Banking portfolio	9.60%
Commitments to lend additional funds to customers with restructured loans	5,800,000
Foreclosed real estate	18,600,000	18,300,000
Personal property acquired in repossession	$ 3,500,000	$ 4,200,000