Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest income
Interest and fees on loans		$ 785,241	$ 998,099	$ 976,990
Interest and dividends on investment securities
Taxable		59,806	100,304	119,741
Tax-exempt		58,320	57,565	44,782
Other interest		9,473	16,643	12,623
Total interest income		912,840	1,172,610	1,154,137
Interest expense
Interest on deposits		67,639	237,286	176,118
Interest on federal funds purchased and securities sold under agreements to repurchase		485	1,579	2,006
Interest on other short-term funding		51	138	180
Interest on PPPLF Funding		1,984
Interest on FHLB advances		57,359	69,816	73,668
Interest on long-term funding		22,365	28,116	22,585
Total interest expense		149,883	336,936	274,557
Net interest income		762,957	835,674	879,580
Provision for credit losses		174,006	16,000	0
Net interest income after provision for credit losses		588,950	819,674	879,580
Noninterest income
Noninterest Income In Scope of Topic 606		246,077	288,247	290,084
Capital markets, net		27,966	19,862	20,120
Mortgage banking, net		45,580	31,878	19,911
Bank and corporate owned life insurance		13,771	14,845	13,951
Asset gains (losses), net(b)	[1]	155,589	2,713	(1,103)
Investment securities gains (losses), net		9,222	5,957	(1,985)
Gains on sale of branches, net		7,449	0	0
Other		10,200	11,165	9,051
Total noninterest income		514,056	380,824	355,568
Noninterest expense
Personnel		432,151	487,063	482,676
Technology		81,214	82,429	72,674
Occupancy		64,064	62,399	59,121
Business development and advertising		18,428	29,600	30,923
Equipment		21,705	23,550	23,243
Legal and professional		21,546	19,901	23,061
Loan and foreclosure costs		12,600	8,861	7,410
FDIC assessment		20,350	16,250	30,000
Other intangible amortization		10,192	9,948	8,159
Loss on prepayments of FHLB advances		44,650
Other		46,688	46,666	55,530
Total noninterest expense		776,034	793,988	821,799
Income before income taxes		326,972	406,509	413,349
Income tax expense		20,200	79,720	79,786
Net income		306,771	326,790	333,562
Preferred stock dividends		18,358	15,202	10,784
Net income available to common equity		$ 288,413	$ 311,587	$ 322,779
Earnings per common share
Basic		$ 1.87	$ 1.93	$ 1.92
Diluted		$ 1.86	$ 1.91	$ 1.89
Average common shares outstanding
Basic		153,005	160,534	167,345
Diluted		153,642	161,932	169,732
Insurance commissions and fees
Noninterest income
Noninterest Income In Scope of Topic 606		$ 45,245	$ 89,104	$ 89,511
Wealth management fees(a)
Noninterest income
Noninterest Income In Scope of Topic 606	[2]	84,957	83,467	82,562
Service charges and deposit account fees
Noninterest income
Noninterest Income In Scope of Topic 606		56,307	63,135	66,075
Card-based fees(b)
Noninterest income
Noninterest Income In Scope of Topic 606		38,605	39,912	39,810
Card-based fees		38,534	39,755	39,656
Other revenue
Noninterest income
Noninterest Income In Scope of Topic 606		20,963	12,629	12,126
Card-based fees		19,238	18,942	17,818
Risk Management and Shared Serivies [Member]
Noninterest expense
Loss on prepayments of FHLB advances		45,000
Operating Segments [Member] | Risk Management and Shared Serivies [Member]
Noninterest expense
Acquisition related costs(c)	[3]	$ 2,447	$ 7,320	$ 29,002

[1] (b) The year ended December 31, 2020 includes a gain of $163 million from the sale of ABRC. 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 the First Staunton, Huntington branch, and Bank Mutual acquisition related costs only.