Loans and Allowance for Credit Losses for Loans - Loan Portfolio (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 49,922,042	$ 50,210,295
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	9,104,193	9,230,543
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	31,705,464	31,970,047
Commercial real estate | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	28,148,953	28,243,239
Commercial real estate | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	3,556,511	3,726,808
Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	5,618,355	5,569,010
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	3,494,030	3,440,695
Consumer loans | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	564,083	559,152
Consumer loans | Automobile
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,700,508	1,620,389
Consumer loans | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 1,229,439	$ 1,261,154