Parent Company Condensed Financial Statements (Condensed Statement of Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of income
Interest expense on long-term debt	$ 87,163	$ 217,849	$ 414,487
Compensation and employee benefits	433,728	404,071	401,700
Amortization of tax credit and other investments	122,457	70,082	98,383
Other expense	81,798	79,489	92,249
Income tax benefit	(183,396)	(117,968)	(169,882)
NET INCOME	872,981	567,797	674,035
Parent Company
Statement of income
Other income	11	3	425
Total income	200,093	511,112	190,614
Interest expense on long-term debt	2,974	3,877	6,482
Compensation and employee benefits	6,370	6,210	5,479
Amortization of tax credit and other investments	425	1,248	8,437
Other expense	1,306	1,184	1,487
Total expense	11,075	12,519	21,885
Income before income tax benefit and equity in undistributed income of subsidiaries	189,018	498,593	168,729
Income tax benefit	3,005	4,158	6,737
Undistributed earnings of subsidiaries, primarily bank	680,958	65,046	498,569
NET INCOME	872,981	567,797	674,035
Parent Company | Bank
Statement of income
Dividends from subsidiaries	200,000	511,000	190,000
Parent Company | Nonbank
Statement of income
Dividends from subsidiaries	$ 82	$ 109	$ 189