Loans, Leases, And Allowance For Credit Losses (Schedule Of Investment Of Accruing And Nonaccruing Loans Modified As Troubled Debt Restructurings) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, subsequent default, recorded investment	$ 3	$ 1	$ 6	$ 3
Loans modified as troubled debt restructurings loans					$ 190	$ 73
Commercial
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, subsequent default, recorded investment			6	3
Accruing
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, subsequent default, recorded investment	0	0	0	0
Accruing | Commercial
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, subsequent default, recorded investment			0	0
Nonaccruing
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, subsequent default, recorded investment	3	1	6	3
Nonaccruing | Commercial
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, subsequent default, recorded investment			6	3
Commercial and industrial | Commercial
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, subsequent default, recorded investment	3	1	6	2
Commercial and industrial | Accruing | Commercial
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, subsequent default, recorded investment	0	0	0	0
Commercial and industrial | Nonaccruing | Commercial
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, subsequent default, recorded investment	$ 3	$ 1	6	2
Owner-occupied | Commercial
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, subsequent default, recorded investment			0	1
Owner-occupied | Accruing | Commercial
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, subsequent default, recorded investment			0	0
Owner-occupied | Nonaccruing | Commercial
Financing Receivable, Modifications [Line Items]
Financing receivable, modifications, subsequent default, recorded investment			$ 0	$ 1