Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2022	Apr. 29, 2022
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Entity Registrant Name	M&T BANK CORPORATION
Entity Central Index Key	0000036270
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		179,417,450
Entity File Number	1-9861
Entity Tax Identification Number	16-0968385
Entity Incorporation, State or Country Code	NY
Entity Address, Address Line One	One M & T Plaza
Entity Address, Postal Zip Code	14203
Entity Address, City or Town	Buffalo
Entity Address, State or Province	NY
City Area Code	716
Local Phone Number	635-4000
Document Quarterly Report	true
Document Transition Report	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Common Stock [Member]
Document Information [Line Items]
Trading Symbol	MTB
Title of 12(b) Security	Common Stock, $.50 par value
Security Exchange Name	NYSE
Series H Preferred Stock [Member]
Document Information [Line Items]
Trading Symbol	MTBPrH
Title of 12(b) Security	Perpetual Fixed-to-Floating RateNon-Cumulative Preferred Stock, Series H
Security Exchange Name	NYSE