Loans and Allowance for Loan Losses (Schedule of Current, Accruing Past Due and Nonaccrual Loans) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	$ 44,044,939	$ 43,716,353
Non-accrual with an ALL	164,452	113,519
Non-accrual without an ALL	18,008	14,542
Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	22,600,176	22,066,656
Non-accrual with an ALL	104,383	57,507
Non-accrual without an ALL	15,404	11,904
Total commercial and industrial | Commercial, financial and agricultural
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	14,201,398	13,874,416
Non-accrual with an ALL	78,792	48,008
Non-accrual without an ALL	15,404	11,299
Total commercial and industrial | Owner-occupied
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	8,398,778	8,192,240
Non-accrual with an ALL	25,591	9,499
Non-accrual without an ALL	0	605
Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	8,448,008	8,999,384
Non-accrual with an ALL	54,360	50,897
Non-accrual without an ALL	32	0
Total consumer | Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	5,246,640	5,214,443
Non-accrual with an ALL	39,536	36,847
Non-accrual without an ALL	0	0
Total consumer | Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,757,250	1,757,038
Non-accrual with an ALL	7,967	6,830
Non-accrual without an ALL	0	0
Total consumer | Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	184,595	203,612
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	1,259,523	1,824,291
Non-accrual with an ALL	6,857	7,220
Non-accrual without an ALL	32	0
Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	12,996,755	12,650,313
Non-accrual with an ALL	5,709	5,115
Non-accrual without an ALL	2,572	2,638
Total commercial real estate | Investment properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	11,976,830	11,644,047
Non-accrual with an ALL	1,935	1,785
Non-accrual without an ALL	1,678	1,688
Total commercial real estate | 1-4 family properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	596,650	616,933
Non-accrual with an ALL	2,621	2,172
Non-accrual without an ALL	894	950
Total commercial real estate | Land and development
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	423,275	389,333
Non-accrual with an ALL	1,153	1,158
Non-accrual without an ALL	0	0
Current
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	43,807,426	43,522,724
Current | Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	22,465,388	21,980,288
Current | Total commercial and industrial | Commercial, financial and agricultural
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	14,095,704	13,798,639
Current | Total commercial and industrial | Owner-occupied
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	8,369,684	8,181,649
Current | Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	8,355,916	8,901,675
Current | Total consumer | Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	5,194,675	5,163,417
Current | Total consumer | Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,742,419	1,742,412
Current | Total consumer | Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	181,091	200,047
Current | Total consumer | Other consumer loans
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,237,731	1,795,799
Current | Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	12,986,122	12,640,761
Current | Total commercial real estate | Investment properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	11,971,387	11,639,614
Current | Total commercial real estate | 1-4 family properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	592,680	613,049
Current | Total commercial real estate | Land and development
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	422,055	388,098
Accruing 30-89 Days Past Due
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	51,524	62,195
Accruing 30-89 Days Past Due | Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	13,178	15,520
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	9,723	15,033
Accruing 30-89 Days Past Due | Total commercial and industrial | Owner-occupied
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	3,455	487
Accruing 30-89 Days Past Due | Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	35,994	44,876
Accruing 30-89 Days Past Due | Total consumer | Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	12,429	13,969
Accruing 30-89 Days Past Due | Total consumer | Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	6,863	7,795
Accruing 30-89 Days Past Due | Total consumer | Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,799	1,843
Accruing 30-89 Days Past Due | Total consumer | Other consumer loans
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	14,903	21,269
Accruing 30-89 Days Past Due | Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	2,352	1,799
Accruing 30-89 Days Past Due | Total commercial real estate | Investment properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,830	960
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	455	762
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	67	77
Accruing 90 Days or Greater Past Due
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	3,529	3,373
Accruing 90 Days or Greater Past Due | Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,823	1,437
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	1,775	1,437
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	48	0
Accruing 90 Days or Greater Past Due | Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,706	1,936
Accruing 90 Days or Greater Past Due | Total consumer | Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	0	210
Accruing 90 Days or Greater Past Due | Total consumer | Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1	1
Accruing 90 Days or Greater Past Due | Total consumer | Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,705	1,722
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	3
Accruing 90 Days or Greater Past Due | Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	0	0
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	0
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	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
Total Accruing Past Due
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	55,053	65,568
Total Accruing Past Due | Total commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	15,001	16,957
Total Accruing Past Due | Total commercial and industrial | Commercial, financial and agricultural
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	11,498	16,470
Total Accruing Past Due | Total commercial and industrial | Owner-occupied
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	3,503	487
Total Accruing Past Due | Total consumer
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	37,700	46,812
Total Accruing Past Due | Total consumer | Consumer mortgages
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	12,429	14,179
Total Accruing Past Due | Total consumer | Home equity
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	6,864	7,796
Total Accruing Past Due | Total consumer | Credit cards
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	3,504	3,565
Total Accruing Past Due | Total consumer | Other consumer loans
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	14,903	21,272
Total Accruing Past Due | Total commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	2,352	1,799
Total Accruing Past Due | Total commercial real estate | Investment properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	1,830	960
Total Accruing Past Due | Total commercial real estate | 1-4 family properties
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	455	762
Total Accruing Past Due | Total commercial real estate | Land and development
Financing Receivable, Nonaccrual [Line Items]
Loans, net of deferred fees and costs	$ 67	$ 77