Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash Flows From Operating Activities: [Abstract]
Net income	$ 499,136	$ 280,362
Adjustments to reconcile net income to net cash used in operating activities: [Abstract]
Provision for credit losses	(83,000)	229,092
Change in fair value of mortgage servicing rights due to market assumption changes	(33,778)	85,800
Change in the fair value of mortgage servicing rights due to principal payments	30,949	28,971
Net unrealized (gains) losses from derivative contracts	81,667	(51,323)
Share-based compensation	5,677	14,879
Depreciation and amortization	76,196	74,330
Net amortization of discounts and premiums	14,286	1,921
Net losses (gains) on financial instruments and other losses (gains), net	(57,467)	(4,216)
Net gain on mortgage loans held for sale	(56,423)	(77,039)
Mortgage loans originated for sale	(2,250,282)	(2,773,686)
Proceeds from sale of mortgage loans held for sale	2,376,479	2,757,412
Capitalized mortgage servicing rights	(29,307)	(21,330)
Change in trading and fair value option securities	(782,380)	338,992
Change in receivables	97,430	(936,428)
Change in other assets	206	(8,574)
Change in other liabilities	27,285	421,364
Net cash provided by (used in) operating activities	(83,326)	360,527
Cash Flows From Investing Activities: [Abstract]
Proceeds from maturities or redemptions of investment securities	28,970	35,967
Proceeds from maturities or redemptions of available for sale securities	2,682,934	1,813,057
Purchases of available for sale securities	(3,704,636)	(3,238,556)
Proceeds from sales of available for sale securities	488,274	206,979
Change in amount receivable on unsettled available for sale securities transactions	(176,600)	3,988
Loans originated, net of principal collected	2,690,611	(1,894,663)
Net payments on derivative asset contracts	33,183	(96,109)
Net change in restricted equity securities	93,849	348,896
Proceeds from disposition of assets	141,006	62,677
Purchases of assets	(130,146)	(116,800)
Net cash provided by (used in) investing activities	2,147,445	(2,874,564)
Cash Flows From Financing Activities: [Abstract]
Net change in demand deposits, transaction deposits and savings accounts	2,567,084	7,561,708
Net change in time deposits	(186,413)	(209,876)
Proceeds from (Repayments of) Other Debt	(2,734,198)	(4,839,524)
Repayment of subordinated debentures	(150,000)	0
Net proceeds on derivative liability contracts	(32,591)	102,064
Net change in derivative margin accounts	(834,108)	(260,949)
Change in amount due on unsettled available for sale securities transactions	234,589	54,408
Issuance of common and treasury stock, net	(4,866)	(5,022)
Repurchase of common stock	(104,512)	(33,380)
Dividends paid	(107,699)	(107,842)
Net cash provided by (used in) financing activities	(1,352,714)	2,261,587
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect, Total	711,405	(252,450)
Cash and cash equivalents at beginning of period	1,180,573	1,258,821
Cash and cash equivalents at end of period	1,891,978	1,006,371
Supplemental Cash Flow Information: [Abstract]
Cash paid for interest	52,304	138,877
Cash paid for taxes	120,879	91,977
Net loans and bank premises transferred to repossessed real estate and other assets	8,175	42,099
Residential mortgage loans guaranteed by U.S. government agencies that became eligible for repurchase during the period	69,541	239,200
Conveyance of other real estate owned guaranteed by U.S. government agencies	4,956	9,165
Right-of-use assets obtained in exchange for operating lease liabilities	$ 14,551	$ 9,481