Loans And Allowance For Credit Losses (Summary Of Loans In The Personal Banking Portfolio Percentage Of Balances Outstanding ) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Loans And Allowance For Credit Losses [Abstract]
Credit Quality Personal Real Estate Loans Excluded	$ 191.1	$ 198.2
Consumer Healthcare Loans Excluded	$ 188.1	$ 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] \| Under 600 [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	0.80%	1.00%
Real Estate - Personal [Member] \| 600 - 659 [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	1.90%	1.90%
Real Estate - Personal [Member] \| 660 - 719 [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	8.80%	9.20%
Real Estate - Personal [Member] \| 720 - 779 [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	24.50%	25.70%
Real Estate - Personal [Member] \| 780 and over [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	64.00%	62.20%
Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	100.00%	100.00%
Consumer [Member] \| Under 600 [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	2.30%	3.00%
Consumer [Member] \| 600 - 659 [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	4.20%	5.20%
Consumer [Member] \| 660 - 719 [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	14.10%	15.40%
Consumer [Member] \| 720 - 779 [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	23.90%	27.00%
Consumer [Member] \| 780 and over [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	55.50%	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] \| Under 600 [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	1.30%	1.70%
Revolving Home Equity [Member] \| 600 - 659 [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	2.40%	1.90%
Revolving Home Equity [Member] \| 660 - 719 [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	8.60%	9.00%
Revolving Home Equity [Member] \| 720 - 779 [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	22.20%	21.50%
Revolving Home Equity [Member] \| 780 and over [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	65.50%	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] \| Under 600 [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	5.00%	5.60%
Consumer Credit Card [Member] \| 600 - 659 [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	12.30%	14.30%
Consumer Credit Card [Member] \| 660 - 719 [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	31.20%	32.20%
Consumer Credit Card [Member] \| 720 - 779 [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	28.00%	26.60%
Consumer Credit Card [Member] \| 780 and over [Member]
Loans And Allowance For Loan Losses [Line Items]
Percentage of Loan Category	23.50%	21.30%