Loans and Allowance for Loan Losses - Schedule of Current, Accruing Past Due, and Non-Accrual Loans by Portfolio Class (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	$ 43,120,674	$ 43,404,490
Non-accrual with an ALL	297,218	216,667
Non-accrual without an ALL	15,746	71,510
Accrued interest receivable	$ 221,900	$ 256,300
Financing receivable, accrued interest, after allowance for credit loss, statement of financial position [extensible enumeration]	Other assets	Other assets
Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	$ 22,663,997	$ 22,598,493
Non-accrual with an ALL	141,339	137,184
Non-accrual without an ALL	14,055	44,056
Total commercial and industrial \| Commercial, financial and agricultural
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	14,563,913	14,459,345
Non-accrual with an ALL	94,339	66,400
Non-accrual without an ALL	12,665	23,470
Total commercial and industrial \| Owner-occupied
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	8,100,084	8,139,148
Non-accrual with an ALL	47,000	70,784
Non-accrual without an ALL	1,390	20,586
Total commercial and industrial \| Senior Housing Loans
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	3,100,000	3,280,000
Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	12,177,484	12,316,758
Non-accrual with an ALL	85,114	16,205
Non-accrual without an ALL	1,691	27,425
Total commercial real estate \| Investment properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	11,346,549	11,363,304
Non-accrual with an ALL	80,729	12,796
Non-accrual without an ALL	1,542	26,974
Total commercial real estate \| 1-4 family properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	528,130	598,502
Non-accrual with an ALL	2,695	2,605
Non-accrual without an ALL	149	451
Total commercial real estate \| Land and development
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	302,805	354,952
Non-accrual with an ALL	1,690	804
Non-accrual without an ALL	0	0
Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	8,279,193	8,489,239
Non-accrual with an ALL	70,765	63,278
Non-accrual without an ALL	0	29
Total consumer \| Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	5,323,443	5,411,723
Non-accrual with an ALL	48,956	46,108
Non-accrual without an ALL	0	0
Total consumer \| Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,809,286	1,807,399
Non-accrual with an ALL	15,837	10,473
Non-accrual without an ALL	0	0
Total consumer \| Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	181,386	194,141
Non-accrual with an ALL	0	0
Non-accrual without an ALL	0	0
Total consumer \| Other consumer loans
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	965,078	1,075,976
Non-accrual with an ALL	5,972	6,697
Non-accrual without an ALL	0	29
Current
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	42,710,481	43,057,214
Current \| Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	22,450,422	22,396,987
Current \| Total commercial and industrial \| Commercial, financial and agricultural
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	14,442,436	14,355,414
Current \| Total commercial and industrial \| Owner-occupied
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	8,007,986	8,041,573
Current \| Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	12,085,220	12,271,352
Current \| Total commercial real estate \| Investment properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	11,260,803	11,322,516
Current \| Total commercial real estate \| 1-4 family properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	524,304	595,359
Current \| Total commercial real estate \| Land and development
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	300,113	353,477
Current \| Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	8,174,839	8,388,875
Current \| Total consumer \| Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	5,266,124	5,359,153
Current \| Total consumer \| Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,782,849	1,785,836
Current \| Total consumer \| Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	178,182	190,299
Current \| Total consumer \| Other consumer loans
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	947,684	1,053,587
Accruing 30-89 Days Past Due
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	92,870	54,046
Accruing 30-89 Days Past Due \| Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	56,245	18,320
Accruing 30-89 Days Past Due \| Total commercial and industrial \| Commercial, financial and agricultural
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	12,537	12,264
Accruing 30-89 Days Past Due \| Total commercial and industrial \| Owner-occupied
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	43,708	6,056
Accruing 30-89 Days Past Due \| Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	4,687	1,498
Accruing 30-89 Days Past Due \| Total commercial real estate \| Investment properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	2,865	740
Accruing 30-89 Days Past Due \| Total commercial real estate \| 1-4 family properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	820	87
Accruing 30-89 Days Past Due \| Total commercial real estate \| Land and development
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,002	671
Accruing 30-89 Days Past Due \| Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	31,938	34,228
Accruing 30-89 Days Past Due \| Total consumer \| Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	8,363	6,462
Accruing 30-89 Days Past Due \| Total consumer \| Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	10,600	10,374
Accruing 30-89 Days Past Due \| Total consumer \| Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,589	1,818
Accruing 30-89 Days Past Due \| Total consumer \| Other consumer loans
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	11,386	15,574
Accruing 90 Days or Greater Past Due
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	4,359	5,053
Accruing 90 Days or Greater Past Due \| Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,936	1,946
Accruing 90 Days or Greater Past Due \| Total commercial and industrial \| Commercial, financial and agricultural
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,936	1,797
Accruing 90 Days or Greater Past Due \| Total commercial and industrial \| Owner-occupied
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	0	149
Accruing 90 Days or Greater Past Due \| Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	772	278
Accruing 90 Days or Greater Past Due \| Total commercial real estate \| Investment properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	610	278
Accruing 90 Days or Greater Past Due \| Total commercial real estate \| 1-4 family properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	162	0
Accruing 90 Days or Greater Past Due \| Total commercial real estate \| Land and development
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	0	0
Accruing 90 Days or Greater Past Due \| Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,651	2,829
Accruing 90 Days or Greater Past Due \| Total consumer \| Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	0	0
Accruing 90 Days or Greater Past Due \| Total consumer \| Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	0	716
Accruing 90 Days or Greater Past Due \| Total consumer \| Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,615	2,024
Accruing 90 Days or Greater Past Due \| Total consumer \| Other consumer loans
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	36	89
Total Accruing Past Due
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	97,229	59,099
Total Accruing Past Due \| Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	58,181	20,266
Total Accruing Past Due \| Total commercial and industrial \| Commercial, financial and agricultural
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	14,473	14,061
Total Accruing Past Due \| Total commercial and industrial \| Owner-occupied
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	43,708	6,205
Total Accruing Past Due \| Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	5,459	1,776
Total Accruing Past Due \| Total commercial real estate \| Investment properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	3,475	1,018
Total Accruing Past Due \| Total commercial real estate \| 1-4 family properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	982	87
Total Accruing Past Due \| Total commercial real estate \| Land and development
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,002	671
Total Accruing Past Due \| Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	33,589	37,057
Total Accruing Past Due \| Total consumer \| Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	8,363	6,462
Total Accruing Past Due \| Total consumer \| Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	10,600	11,090
Total Accruing Past Due \| Total consumer \| Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	3,204	3,842
Total Accruing Past Due \| Total consumer \| Other consumer loans
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	$ 11,422	$ 15,663

Loans and Allowance for Loan Losses - Schedule of Current, Accruing Past Due, and Non-Accrual Loans by Portfolio Class (Details) - USD ($)
$ in Thousands