Loans and Allowance for Credit Losses for Loans - Past Due, Current, and Non-Accrual Loans Without an Allowance for Credit Losses by Loan Portfolio Class (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
Loans	$ 50,210,295	$ 46,917,200
Non-Accrual Loans	291,871	269,761
Non-Accrual Loans Without Allowance for Loan Losses	115,126	102,186
Total Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	383,497	360,649
30-59 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	59,214	43,535
60-89 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	19,267	20,766
90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	13,145	26,587
Current Loans
Financing Receivable, Past Due [Line Items]
Loans	49,826,798	46,556,551
Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans	9,230,543	8,804,830
Non-Accrual Loans	99,912	98,881
Non-Accrual Loans Without Allowance for Loan Losses	6,594	5,659
Commercial and industrial | Total Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	119,893	141,642
Commercial and industrial | 30-59 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	9,307	11,664
Commercial and industrial | 60-89 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	5,095	12,705
Commercial and industrial | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	5,579	18,392
Commercial and industrial | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	9,110,650	8,663,188
Commercial real estate
Financing Receivable, Past Due [Line Items]
Loans	31,970,047	29,432,868
Non-Accrual Loans	160,590	142,546
Non-Accrual Loans Without Allowance for Loan Losses	93,289	82,186
Commercial real estate | Total Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	168,845	158,633
Commercial real estate | 30-59 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	3,008	6,638
Commercial real estate | 60-89 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	1,257	3,167
Commercial real estate | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	3,990	6,282
Commercial real estate | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	31,801,202	29,274,235
Commercial real estate | Commercial real estate
Financing Receivable, Past Due [Line Items]
Loans	28,243,239	25,732,033
Non-Accrual Loans	99,739	68,316
Non-Accrual Loans Without Allowance for Loan Losses	81,282	66,066
Commercial real estate | Commercial real estate | Total Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	104,004	80,413
Commercial real estate | Commercial real estate | 30-59 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	3,008	6,638
Commercial real estate | Commercial real estate | 60-89 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	1,257	3,167
Commercial real estate | Commercial real estate | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	0	2,292
Commercial real estate | Commercial real estate | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	28,139,235	25,651,620
Commercial real estate | Construction
Financing Receivable, Past Due [Line Items]
Loans	3,726,808	3,700,835
Non-Accrual Loans	60,851	74,230
Non-Accrual Loans Without Allowance for Loan Losses	12,007	16,120
Commercial real estate | Construction | Total Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	64,841	78,220
Commercial real estate | Construction | 30-59 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	0	0
Commercial real estate | Construction | 60-89 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	0	0
Commercial real estate | Construction | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	3,990	3,990
Commercial real estate | Construction | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	3,661,967	3,622,615
Residential mortgage
Financing Receivable, Past Due [Line Items]
Loans	5,569,010	5,364,550
Non-Accrual Loans	26,986	25,160
Non-Accrual Loans Without Allowance for Loan Losses	14,654	14,224
Residential mortgage | Total Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	64,019	46,487
Residential mortgage | 30-59 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	26,345	16,146
Residential mortgage | 60-89 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	8,200	3,315
Residential mortgage | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	2,488	1,866
Residential mortgage | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	5,504,991	5,318,063
Home equity
Financing Receivable, Past Due [Line Items]
Loans	3,440,695	3,314,952
Non-Accrual Loans	4,383	3,174
Non-Accrual Loans Without Allowance for Loan Losses	589	117
Home equity | Total Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	30,740	13,887
Home equity | 30-59 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	20,554	9,087
Home equity | 60-89 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	4,715	1,579
Home equity | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	1,088	47
Home equity | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	3,409,955	3,301,065
Home equity | Home equity
Financing Receivable, Past Due [Line Items]
Loans	559,152	503,884
Non-Accrual Loans	3,539	2,810
Non-Accrual Loans Without Allowance for Loan Losses	0	117
Home equity | Home equity | Total Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	5,839	4,019
Home equity | Home equity | 30-59 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	1,687	955
Home equity | Home equity | 60-89 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	613	254
Home equity | Home equity | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	0	0
Home equity | Home equity | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	553,313	499,865
Home equity | Automobile
Financing Receivable, Past Due [Line Items]
Loans	1,620,389	1,746,225
Non-Accrual Loans	212	271
Non-Accrual Loans Without Allowance for Loan Losses	0	0
Home equity | Automobile | Total Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	14,493	6,876
Home equity | Automobile | 30-59 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	11,850	5,974
Home equity | Automobile | 60-89 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	1,855	630
Home equity | Automobile | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	576	1
Home equity | Automobile | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	1,605,896	1,739,349
Home equity | Other consumer
Financing Receivable, Past Due [Line Items]
Loans	1,261,154	1,064,843
Non-Accrual Loans	632	93
Non-Accrual Loans Without Allowance for Loan Losses	589	0
Home equity | Other consumer | Total Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	10,408	2,992
Home equity | Other consumer | 30-59 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	7,017	2,158
Home equity | Other consumer | 60-89 Days Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	2,247	695
Home equity | Other consumer | 90 Days or More Past Due Loans
Financing Receivable, Past Due [Line Items]
Loans	512	46
Home equity | Other consumer | Current Loans
Financing Receivable, Past Due [Line Items]
Loans	$ 1,250,746	$ 1,061,851