Loans and Leases - Performance of Loans that have been Modified in the Last 12 Months (Details) $ in Millions	Mar. 31, 2025 USD ($)
Financing Receivable, Troubled Debt Restructuring [Line Items]
Non-Accruing	$ 86
Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	313
30-89 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	0
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	16
Commercial: | Commercial and industrial | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	133
Commercial: | Commercial and industrial | 30-89 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	0
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	69
Commercial: | Commercial real estate | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	178
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	1
Consumer: | Consumer Real Estate | Current
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans	2
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