Loans and Leases - Asset Quality Indicators (Details) - Commercial	Sep. 30, 2020
Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades	16
Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades	13
Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades	14
Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades	15
Minimum | PD Grade 1
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lowest expected default probability	1
Minimum | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades	1
Minimum | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades	13
Maximum | Loss
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades	16
Maximum | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades	12