Loans and Allowance for Loan Losses (Schedule of Current, Accruing Past Due and Nonaccrual Loans) (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	$ 42,571,458	$ 39,311,958
Non-accrual with an ALL	92,522	100,518
Non-accrual without an ALL	29,572	30,524
Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	21,212,516	19,622,924
Non-accrual with an ALL	41,540	45,064
Non-accrual without an ALL	26,168	27,919
Total commercial and industrial | Commercial, financial and agricultural
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	13,254,966	12,147,858
Non-accrual with an ALL	33,712	37,918
Non-accrual without an ALL	25,563	23,869
Total commercial and industrial | Owner-occupied
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	7,957,550	7,475,066
Non-accrual with an ALL	7,828	7,146
Non-accrual without an ALL	605	4,050
Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	12,287,965	11,015,111
Non-accrual with an ALL	6,396	9,726
Non-accrual without an ALL	3,404	2,605
Total commercial real estate | Investment properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	11,238,404	9,902,776
Non-accrual with an ALL	2,702	3,273
Non-accrual without an ALL	2,339	2,577
Total commercial real estate | 1-4 family properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	639,627	645,469
Non-accrual with an ALL	2,026	4,535
Non-accrual without an ALL	1,065	28
Total commercial real estate | Land and development
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	409,934	466,866
Non-accrual with an ALL	1,668	1,918
Non-accrual without an ALL	0	0
Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	9,070,977	8,673,923
Non-accrual with an ALL	44,586	45,728
Non-accrual without an ALL	0	0
Total consumer | Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	5,166,928	5,068,998
Non-accrual with an ALL	32,527	29,078
Non-accrual without an ALL	0	0
Total consumer | Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,708,246	1,361,419
Non-accrual with an ALL	7,121	9,773
Non-accrual without an ALL	0	0
Total consumer | Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	197,978	204,172
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	1,997,825	2,039,334
Non-accrual with an ALL	4,938	6,877
Non-accrual without an ALL	0	0
Current
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	42,385,819	39,123,351
Current | Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	21,124,274	19,528,924
Current | Total commercial and industrial | Commercial, financial and agricultural
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	13,180,498	12,068,740
Current | Total commercial and industrial | Owner-occupied
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	7,943,776	7,460,184
Current | Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	12,276,250	10,998,504
Current | Total commercial real estate | Investment properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	11,232,942	9,894,924
Current | Total commercial real estate | 1-4 family properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	635,157	639,631
Current | Total commercial real estate | Land and development
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	408,151	463,949
Current | Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	8,985,295	8,595,923
Current | Total consumer | Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	5,123,759	5,033,537
Current | Total consumer | Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,695,825	1,349,027
Current | Total consumer | Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	194,860	201,929
Current | Total consumer | Other consumer loans
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,970,851	2,011,430
Accruing 30-89 Days Past Due
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	60,102	50,795
Accruing 30-89 Days Past Due | Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	18,723	17,005
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	14,050	13,378
Accruing 30-89 Days Past Due | Total commercial and industrial | Owner-occupied
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	4,673	3,627
Accruing 30-89 Days Past Due | Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,915	3,312
Accruing 30-89 Days Past Due | Total commercial real estate | Investment properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	421	1,285
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	1,379	1,182
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	115	845
Accruing 30-89 Days Past Due | Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	39,464	30,478
Accruing 30-89 Days Past Due | Total consumer | Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	10,642	6,257
Accruing 30-89 Days Past Due | Total consumer | Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	5,225	2,619
Accruing 30-89 Days Past Due | Total consumer | Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,561	1,233
Accruing 30-89 Days Past Due | Total consumer | Other consumer loans
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	22,036	20,369
Accruing 90 Days or Greater Past Due
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	3,443	6,770
Accruing 90 Days or Greater Past Due | Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,811	4,012
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	1,143	3,953
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	668	59
Accruing 90 Days or Greater Past Due | Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	0	964
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	0	717
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	0	93
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	154
Accruing 90 Days or Greater Past Due | Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,632	1,794
Accruing 90 Days or Greater Past Due | Total consumer | Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	0	126
Accruing 90 Days or Greater Past Due | Total consumer | Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	75	0
Accruing 90 Days or Greater Past Due | Total consumer | Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,557	1,010
Accruing 90 Days or Greater Past Due | Total consumer | Other consumer loans
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	0	658
Total Accruing Past Due
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	63,545	57,565
Total Accruing Past Due | Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	20,534	21,017
Total Accruing Past Due | Total commercial and industrial | Commercial, financial and agricultural
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	15,193	17,331
Total Accruing Past Due | Total commercial and industrial | Owner-occupied
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	5,341	3,686
Total Accruing Past Due | Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,915	4,276
Total Accruing Past Due | Total commercial real estate | Investment properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	421	2,002
Total Accruing Past Due | Total commercial real estate | 1-4 family properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,379	1,275
Total Accruing Past Due | Total commercial real estate | Land and development
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	115	999
Total Accruing Past Due | Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	41,096	32,272
Total Accruing Past Due | Total consumer | Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	10,642	6,383
Total Accruing Past Due | Total consumer | Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	5,300	2,619
Total Accruing Past Due | Total consumer | Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	3,118	2,243
Total Accruing Past Due | Total consumer | Other consumer loans
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	$ 22,036	$ 21,027