Loans and Leases and the Allowance for Credit Losses - Summary of Current, Past Due and Nonaccrual Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	$ 123,740,992	$ 89,043,040
30-89 Days Past Due	1,578,766	845,930
Accruing Loans Past Due 90 Days or More	476,503	963,399
Nonaccrual	2,429,326	2,060,083
Loans and leases, net of unearned discount	128,225,587	92,912,452
Commercial, Financial, Leasing, etc. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	37,938,053	23,101,810
30-89 Days Past Due	481,091	142,208
Accruing Loans Past Due 90 Days or More	20,639	8,284
Nonaccrual	368,166	221,022
Loans and leases, net of unearned discount	38,807,949	23,473,324
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	35,880,425	24,712,643
30-89 Days Past Due	227,399	319,099
Accruing Loans Past Due 90 Days or More	38,470	31,733
Nonaccrual	1,406,200	1,069,280
Loans and leases, net of unearned discount	37,552,494	26,132,755
Residential Builder and Developer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,377,505	1,400,437
30-89 Days Past Due	62	2,904
Nonaccrual	1,930	3,005
Loans and leases, net of unearned discount	1,379,497	1,406,346
Other Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	6,981,412	7,722,049
30-89 Days Past Due	157,175	17,175
Accruing Loans Past Due 90 Days or More	1,900
Nonaccrual	66,187	111,405
Loans and leases, net of unearned discount	7,206,674	7,850,629
Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	20,709,362	13,294,872
30-89 Days Past Due	580,357	239,561
Accruing Loans Past Due 90 Days or More	411,731	920,080
Nonaccrual	285,395	355,858
Loans and leases, net of unearned discount	21,986,845	14,810,371
Residential Limited Documentation [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	974,779	1,124,520
30-89 Days Past Due	17,274	16,666
Nonaccrual	95,382	122,888
Loans and leases, net of unearned discount	1,087,435	1,264,074
Home Equity Lines and Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	4,959,845	3,476,617
30-89 Days Past Due	25,370	15,486
Nonaccrual	78,208	70,488
Loans and leases, net of unearned discount	5,063,423	3,562,591
Recreational Finance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	8,738,849	7,985,173
30-89 Days Past Due	41,758	40,544
Nonaccrual	38,718	27,811
Loans and leases, net of unearned discount	8,819,325	8,053,528
Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	4,282,895	4,604,772
30-89 Days Past Due	35,550	40,064
Nonaccrual	40,318	34,037
Loans and leases, net of unearned discount	4,358,763	4,678,873
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,897,867	1,620,147
30-89 Days Past Due	12,730	12,223
Accruing Loans Past Due 90 Days or More	3,763	3,302
Nonaccrual	48,822	44,289
Loans and leases, net of unearned discount	$ 1,963,182	$ 1,679,961