Consolidated Statements of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flows from Operating Activities
Net income		$ 326,790	$ 333,562	$ 229,264
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses		16,000	0	26,000
Depreciation and amortization		58,149	48,253	46,967
Addition to (recovery of) valuation allowance on mortgage servicing rights, net		63	(545)	175
Amortization of mortgage servicing rights		12,432	9,594	10,084
Amortization of Intangible Assets		9,948	8,159	1,959
Amortization and accretion on earning assets, funding, and other, net		23,573	11,624	37,476
Net amortization of tax credit investments		20,062	19,425	19,834
Deferred income taxes		13,833	46,947	21,402
Losses (gains) on sales of investment securities, net		(5,957)	1,985	(434)
Asset (gains) losses, net	[1]	(2,713)	1,103	1,244
(Gain) loss on mortgage banking activities, net		(20,120)	(22,497)	(3,516)
Mortgage loans originated for sale		(1,090,792)	(1,092,318)	(715,357)
Proceeds from sales of mortgage loans held for sale		1,317,077	1,131,652	819,950
Pension contributions		0	(41,877)	(6,242)
(Increase) decrease in interest receivable		7,595	(7,417)	(9,476)
Increase (decrease) in interest payable		2,495	10,407	6,535
Increase (decrease) in accrued expenses		723	30,924	3,520
Increase (decrease) in derivative asset		(102,966)	40,950	(13,076)
Net change in other assets and other liabilities		(11,930)	(33,363)	(17,941)
Net cash provided by operating activities		574,260	496,567	458,368
Cash Flows from Investing Activities
Net increase in loans		(137,990)	(326,464)	(861,934)
Purchases of
Available for sale securities		(460,124)	(737,580)	(1,137,191)
Held to maturity securities		(423,682)	(682,622)	(234,379)
Federal Home Loan Bank and Federal Reserve Bank stocks		(246,836)	(347,323)	(262,986)
Premises, equipment, and software, net of disposals		(67,459)	(65,854)	(47,369)
Proceeds from
Sales of available for sale securities		1,367,476	601,130	18,467
Sale of Federal Home Loan Bank and Federal Reserve Bank stocks		270,023	282,145	237,656
Prepayments, calls, and maturities of available for sale investment securities		561,659	633,859	713,486
Prepayments, calls, and maturities of held to maturity investment securities		260,510	217,836	210,753
Sales, prepayments, calls and maturities of other assets		10,250	41,856	20,070
Net change in tax credit and alternative investments		(67,632)	(57,327)	(53,770)
Net cash (paid) received in acquisition		551,250	59,472	339
Net cash provided by (used in) investing activities		1,617,446	(380,872)	(1,396,858)
Cash Flows from Financing Activities
Net increase (decrease) in deposits		(1,842,748)	270,481	897,514
Net increase (decrease) in short-term funding		308,039	(581,371)	(217,753)
Net increase (decrease) in short-term FHLB advances		(380,000)	616,000	(198,000)
Repayment of long-term FHLB advances		(764,657)	(2,150,016)	(115,020)
Proceeds from long-term FHLB advances		751,573	1,837,680	750,000
Redemption of Corporation's senior notes		(250,000)	0	0
Finance Lease, Principal Payments		(1)	0	0
Proceeds from issuance of long-term funding		0	300,000	0
Proceeds from issuance of preferred shares		0	97,315	0
Proceeds from issuance of common stock for stock-based compensation plans		11,216	18,408	27,619
Common stock warrants exercised		0	(1)	0
Purchase of preferred shares		0	(537)	0
Purchase of common stock returned to authorized but unissued		0	(33,075)	(37,031)
Purchase of treasury stock		(186,076)	(213,598)	(9,290)
Cash dividends on common stock		(111,804)	(105,519)	(76,417)
Cash dividends on preferred stock		(15,202)	(10,784)	(9,347)
Net cash provided by (used in) financing activities		(2,479,660)	44,983	1,012,275
Net increase (decrease) in cash, cash equivalents, and restricted cash		(287,954)	160,678	73,785
Cash, cash equivalents, and restricted cash at beginning of period		876,698	716,018	642,233
Cash, cash equivalents, and restricted cash at end of period		588,744	876,698	716,018
Supplemental disclosures of cash flow information
Cash paid for interest		332,919	261,724	138,174
Cash paid for income and franchise taxes		41,131	18,335	81,450
Loans and bank premises transferred to other real estate owned		10,513	26,517	11,505
Capitalized mortgage servicing rights		11,606	10,722	7,167
Loans transferred into held for sale from portfolio, net		313,570	33,010	71,954
Transfer of held to maturity securities to available for sale securities (adoption of ASU 2019-04)		692,414	0	0
Unsettled trades to purchase securities		0	883	0
Acquisition
Fair value of assets acquired, including cash and cash equivalents		695,848	2,567,488	647
Fair value ascribed to goodwill and intangible assets		29,837	261,243	6,450
Fair value of liabilities assumed		725,764	2,340,323	54
Common stock issued in acquisition			488,408	7,151
Equity Interests Reversed		(79)
Cash and cash equivalents		400,232	782,784	643,042
Restricted Cash		$ 188,512	$ 93,914	$ 72,976

[1] (b) The year ended December 31, 2019 includes less than $1 million of Huntington related asset losses; the year ended December 31, 2018 includes approximately $2 million of Bank Mutual acquisition related asset losses net of asset gains.