Loans And Allowance For Loan Losses (Summary Of Loans In The Personal Banking Portfolio Percentage Of Balances Outstanding ) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Loans And Allowance For Loan Losses [Line Items]
Credit Quality Personal Real Estate Loans Excluded	$ 216.2	$ 219.2
Consumer Healthcare Loans Excluded	$ 148.9	$ 145.0
Credit quality personal banking loan table percentage loans excluded	7.00%
Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	100.00%	100.00%
Real Estate - Personal [Member] | Fico Under Six Hundred [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	1.30%	1.30%
Real Estate - Personal [Member] | Fico Six Hundred To Six Hundred Fifty Nine [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	1.70%	2.10%
Real Estate - Personal [Member] | Fico Six Hundred Sixty To Seven Hundred Nineteen [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	10.00%	10.50%
Real Estate - Personal [Member] | Fico Seven Hundred Twenty To Seven Hundred Seventy Nine [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	26.00%	25.60%
Real Estate - Personal [Member] | Fico Seven Hundred Eighty And Above [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	61.00%	60.50%
Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	100.00%	100.00%
Consumer [Member] | Fico Under Six Hundred [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	3.50%	3.30%
Consumer [Member] | Fico Six Hundred To Six Hundred Fifty Nine [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	5.30%	5.50%
Consumer [Member] | Fico Six Hundred Sixty To Seven Hundred Nineteen [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	17.30%	17.30%
Consumer [Member] | Fico Seven Hundred Twenty To Seven Hundred Seventy Nine [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	26.90%	26.80%
Consumer [Member] | Fico Seven Hundred Eighty And Above [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	47.00%	47.10%
Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	100.00%	100.00%
Revolving Home Equity [Member] | Fico Under Six Hundred [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	1.10%	1.10%
Revolving Home Equity [Member] | Fico Six Hundred To Six Hundred Fifty Nine [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	1.70%	1.70%
Revolving Home Equity [Member] | Fico Six Hundred Sixty To Seven Hundred Nineteen [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	9.10%	9.50%
Revolving Home Equity [Member] | Fico Seven Hundred Twenty To Seven Hundred Seventy Nine [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	23.20%	21.40%
Revolving Home Equity [Member] | Fico Seven Hundred Eighty And Above [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	64.90%	66.30%
Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	100.00%	100.00%
Consumer Credit Card [Member] | Fico Under Six Hundred [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	5.20%	4.70%
Consumer Credit Card [Member] | Fico Six Hundred To Six Hundred Fifty Nine [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	15.10%	14.40%
Consumer Credit Card [Member] | Fico Six Hundred Sixty To Seven Hundred Nineteen [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	36.10%	34.40%
Consumer Credit Card [Member] | Fico Seven Hundred Twenty To Seven Hundred Seventy Nine [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	25.60%	26.00%
Consumer Credit Card [Member] | Fico Seven Hundred Eighty And Above [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	18.00%	20.50%