Loans and Leases and the Allowance for Credit Losses - Summary of Current, Past Due and Nonaccrual Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	$ 1,656,111	$ 1,779,054
Accruing Loans Past Due 90 Days or More	380,079	491,018
Nonaccrual	2,435,581	2,438,435
Loans and leases, net of unearned discount	133,343,729	131,564,163
Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	128,871,958	126,855,656
Commercial, Financial, Leasing, etc. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	289,931	448,462
Accruing Loans Past Due 90 Days or More	38,039	72,502
Nonaccrual	416,022	347,204
Loans and leases, net of unearned discount	44,683,549	41,850,566
Commercial, Financial, Leasing, etc. [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	43,939,557	40,982,398
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	450,072	311,188
Accruing Loans Past Due 90 Days or More	37,542	67,696
Nonaccrual	1,383,190	1,396,662
Loans and leases, net of unearned discount	36,732,086	36,748,173
Commercial [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	34,861,282	34,972,627
Residential Builder and Developer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	18,745	8,703
Nonaccrual	1,193	1,229
Loans and leases, net of unearned discount	1,135,311	1,314,730
Residential Builder and Developer [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,115,373	1,304,798
Other Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	154,908	239,521
Accruing Loans Past Due 90 Days or More	15,124	549
Nonaccrual	146,024	124,937
Loans and leases, net of unearned discount	6,781,314	7,301,668
Other Commercial Construction [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	6,465,258	6,936,661
Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	581,806	595,897
Accruing Loans Past Due 90 Days or More	284,410	345,402
Nonaccrual	238,509	272,090
Loans and leases, net of unearned discount	22,771,049	22,704,895
Residential [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	21,666,324	21,491,506
Residential Limited Documentation [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	23,945	22,456
Nonaccrual	66,614	77,814
Loans and leases, net of unearned discount	991,168	1,051,052
Residential Limited Documentation [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	900,609	950,782
Home Equity Lines and Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,669,522
30-89 Days Past Due	26,478	30,787
Nonaccrual	77,090	84,788
Loans and leases, net of unearned discount	4,773,090	5,006,886
Home Equity Lines and Loans [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,669,522	4,891,311
Recreational Finance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	9,171,034
30-89 Days Past Due	53,483	54,593
Nonaccrual	32,286	44,630
Loans and leases, net of unearned discount	9,256,803	9,073,394
Recreational Finance [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	9,171,034	8,974,171
Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,020,722
30-89 Days Past Due	40,974	44,486
Nonaccrual	21,791	39,584
Loans and leases, net of unearned discount	4,083,487	4,477,276
Automobile [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,020,722	4,393,206
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,062,277
30-89 Days Past Due	15,769	22,961
Accruing Loans Past Due 90 Days or More	4,964	4,869
Nonaccrual	52,862	49,497
Loans and leases, net of unearned discount	2,135,872	2,035,523
Other [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 2,062,277	$ 1,958,196