Loans and Allowance for Credit Losses for Loans - Loan Portfolio (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 50,097,519	$ 46,917,200
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	9,274,630	8,804,830
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	31,874,319	29,432,868
Commercial real estate | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	28,041,050	25,732,033
Commercial real estate | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	3,833,269	3,700,835
Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	5,562,665	5,364,550
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	3,385,905	3,314,952
Consumer | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	548,918	503,884
Consumer | Automobile
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,585,987	1,746,225
Consumer | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 1,251,000	$ 1,064,843