Loans And Allowance For Credit Losses (Summary Of Loans In The Personal Banking Portfolio Percentage Of Balances Outstanding ) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Loans And Allowance For Loan Losses [Line Items]
Credit Quality Personal Real Estate Loans Excluded	$ 183.3	$ 198.2
Consumer Healthcare Loans Excluded	$ 193.2	$ 199.2
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	1.00%	1.00%
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	2.10%	1.90%
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	8.50%	9.20%
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	25.70%	25.70%
Real Estate - Personal [Member] | Fico Seven Hundred Eighty And Above [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	62.70%	62.20%
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	2.40%	3.00%
Consumer [Member] | Fico Six Hundred To Six Hundred Fifty Nine [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	3.90%	5.20%
Consumer [Member] | Fico Six Hundred Sixty To Seven Hundred Nineteen [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	14.50%	15.40%
Consumer [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%	27.00%
Consumer [Member] | Fico Seven Hundred Eighty And Above [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	53.60%	49.40%
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	1.40%	1.70%
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	2.50%	1.90%
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	7.30%	9.00%
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	22.60%	21.50%
Revolving Home Equity [Member] | Fico Seven Hundred Eighty And Above [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	66.20%	65.90%
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%	5.60%
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	12.90%	14.30%
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	32.20%	32.20%
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	27.50%	26.60%
Consumer Credit Card [Member] | Fico Seven Hundred Eighty And Above [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	22.20%	21.30%