Loans and Leases - Summary of Current, Past Due and Nonaccrual Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	$ 92,040,032	$ 97,628,892
30-89 Days Past Due	845,930	662,439
Accruing Loans Past Due 90 Days or More	963,399	859,208
Nonaccrual	2,060,083	1,893,299
Loans and leases, net of unearned discount	92,912,452	98,535,867
Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	89,043,040	95,120,921
Commercial, Financial, Leasing, etc. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	142,208	60,822
Accruing Loans Past Due 90 Days or More	8,284	10,053
Nonaccrual	221,022	306,827
Loans and leases, net of unearned discount	23,473,324	27,574,564
Commercial, Financial, Leasing, etc. [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	23,101,810	27,196,862
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	319,099	168,917
Accruing Loans Past Due 90 Days or More	31,733	47,014
Nonaccrual	1,069,280	775,894
Loans and leases, net of unearned discount	26,132,755	27,680,340
Commercial [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	24,712,643	26,688,515
Residential Builder and Developer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	2,904	1,693
Accruing Loans Past Due 90 Days or More		856
Nonaccrual	3,005	1,094
Loans and leases, net of unearned discount	1,406,346	1,249,738
Residential Builder and Developer [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,400,437	1,246,095
Other Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	17,175	66,365
Accruing Loans Past Due 90 Days or More		3,816
Nonaccrual	111,405	114,039
Loans and leases, net of unearned discount	7,850,629	8,707,811
Other Commercial Construction [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	7,722,049	8,523,591
Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	239,561	200,406
Accruing Loans Past Due 90 Days or More	920,080	792,888
Nonaccrual	355,858	365,729
Loans and leases, net of unearned discount	14,810,371	15,123,859
Residential [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	13,294,872	13,764,836
Residential Limited Documentation [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	16,666	19,687
Nonaccrual	122,888	147,170
Loans and leases, net of unearned discount	1,264,074	1,629,134
Residential Limited Documentation [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,124,520	1,462,277
Home Equity Lines and Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	15,486	24,329
Nonaccrual	70,488	79,392
Loans and leases, net of unearned discount	3,562,591	3,985,606
Home Equity Lines and Loans [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	3,476,617	3,881,885
Recreational Finance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	40,544	47,161
Nonaccrual	27,811	25,519
Loans and leases, net of unearned discount	8,053,528	7,075,323
Recreational Finance [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	7,985,173	7,002,643
Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	40,064	55,498
Nonaccrual	34,037	39,404
Loans and leases, net of unearned discount	4,678,873	4,102,251
Automobile [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	4,604,772	4,007,349
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	12,223	17,561
Accruing Loans Past Due 90 Days or More	3,302	4,581
Nonaccrual	44,289	38,231
Loans and leases, net of unearned discount	1,679,961	1,407,241
Other [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	$ 1,620,147	$ 1,346,868