Loans and Allowance for Credit Losses for Loans - Loan Portfolio (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 50,311,702	$ 50,210,295
Automobile
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,800,000
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	9,479,147	9,230,543
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	31,768,846	31,970,047
Commercial real estate | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	28,223,123	28,243,239
Commercial real estate | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	3,545,723	3,726,808
Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	5,627,113	5,569,010
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	3,436,596	3,440,695
Consumer loans | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	566,467	559,152
Consumer loans | Automobile
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,762,852	1,620,389
Consumer loans | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 1,107,277	$ 1,261,154