Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Interest income
Interest and fees on loans		$ 998,099	$ 976,990	$ 749,000
Interest and dividends on investment securities
Taxable		100,304	119,741	96,909
Tax-exempt		57,565	44,782	32,977
Other interest		16,643	12,623	7,719
Total interest income		1,172,610	1,154,137	886,605
Interest expense
Interest on deposits		237,286	176,118	94,025
Interest on federal funds purchased and securities sold under agreements to repurchase		1,579	2,006	2,527
Interest on other short-term funding		149	186	293
Interest on FHLB advances		69,816	73,668	30,364
Interest on long-term funding		28,106	22,579	18,176
Total interest expense		336,936	274,557	145,385
Net interest income		835,674	879,580	741,220
Provision for credit losses		16,000	0	26,000
Net interest income after provision for credit losses		819,674	879,580	715,220
Noninterest income
Noninterest Income In Scope of Topic 606		288,247	290,084	262,175
Capital markets, net		19,862	20,120	19,642
Mortgage banking, net		31,878	19,911	19,360
Bank and corporate owned life insurance		14,845	13,951	16,250
Asset gains (losses), net(b)	[1]	2,713	(1,103)	(1,244)
Investment securities gains (losses), net		5,957	(1,985)	434
Other		11,165	9,051	9,523
Total noninterest income		380,824	355,568	332,680
Noninterest expense
Personnel		487,063	482,676	428,976
Technology		82,429	72,674	63,004
Occupancy		62,399	59,121	53,842
Business development and advertising		29,600	30,923	28,946
Equipment		23,550	23,243	21,201
Legal and professional		19,901	23,061	22,509
Loan and foreclosure costs		8,861	7,410	7,293
FDIC assessment		16,250	30,000	31,300
Other intangible amortization		9,948	8,159	1,959
Other		46,666	55,530	50,102
Total noninterest expense		793,988	821,799	709,133
Income before income taxes		406,509	413,349	338,767
Income tax expense		79,720	79,786	109,503
Net income		326,790	333,562	229,264
Preferred stock dividends		15,202	10,784	9,347
Net income available to common equity		$ 311,587	$ 322,779	$ 219,917
Earnings per common share
Basic		$ 1.93	$ 1.92	$ 1.45
Diluted		$ 1.91	$ 1.89	$ 1.42
Average common shares outstanding
Basic		160,534	167,345	150,877
Diluted		161,932	169,732	153,647
Insurance commissions and fees
Noninterest income
Noninterest Income In Scope of Topic 606		$ 89,104	$ 89,511	$ 81,474
Wealth management fees(a)
Noninterest income
Noninterest Income In Scope of Topic 606	[2]	83,467	82,562	70,126
Service charges on deposit account fees
Noninterest income
Noninterest Income In Scope of Topic 606		63,135	66,075	64,427
Card-based fees
Noninterest income
Noninterest Income In Scope of Topic 606		39,912	39,810	34,997
Service charges on deposit account fees		39,755	39,656	34,834
Other fee-based revenue
Noninterest income
Noninterest Income In Scope of Topic 606		12,629	12,126	11,151
Service charges on deposit account fees		18,942	17,818	17,854
Operating Segments [Member] | Risk Management and Shared Serivies [Member]
Noninterest expense
Acquisition related costs(c)	[3]	$ 7,320	29,002	$ 0
Huntington National Bank
Related acquisition asset losses net of asset gains		less than $1 million
Bank Mutual [Member]
Gain (Loss) on Disposition of Assets for Financial Service Operations			$ 2,000

[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.

[2] (a) Includes trust, asset management, brokerage, and annuity fees.

[3] (c) Includes Bank Mutual, Huntington branch, and First Staunton acquisition related costs only.