Loans and Leases - Performance Of Loans That Have Been Modified In The Last 12 Months (Details) $ in Millions	Mar. 31, 2024 USD ($)
Financing Receivable, Troubled Debt Restructuring [Line Items]
Non-Accruing	$ 49
Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	123
30-89 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	1
90+ Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	0
Commercial: | Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Non-Accruing	18
Commercial: | Commercial and industrial | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	100
Commercial: | Commercial and industrial | 30-89 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	1
Commercial: | Commercial and industrial | 90+ Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	0
Commercial: | Commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Non-Accruing	28
Commercial: | Commercial real estate | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	19
Commercial: | Commercial real estate | 30-89 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	0
Commercial: | Commercial real estate | 90+ Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	0
Consumer: | Consumer Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Non-Accruing	3
Consumer: | Consumer Real Estate | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	4
Consumer: | Consumer Real Estate | 30-89 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	0
Consumer: | Consumer Real Estate | 90+ Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	0
Consumer: | Credit Card and Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Non-Accruing	0
Consumer: | Credit Card and Other | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	0
Consumer: | Credit Card and Other | 30-89 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	0
Consumer: | Credit Card and Other | 90+ Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	$ 0