Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Feb. 16, 2024	Jun. 30, 2023
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Entity Registrant Name	M&T BANK CORPORATION
Entity Central Index Key	0000036270
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Entity Public Float			$ 19,900,658,494
Entity Common Stock, Shares Outstanding		166,624,291
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity File Number	1-9861
Entity Incorporation, State or Country Code	NY
Entity Tax Identification Number	16-0968385
Entity Address, City or Town	Buffalo
Entity Address, Address Line One	One M&T Plaza
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	14203
City Area Code	716
Local Phone Number	635-4000
Document Annual Report	true
Document Transition Report	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Auditor Firm ID	238
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	Buffalo, NY, United States
Documents Incorporated by Reference [Text Block]	Portions of the Proxy Statement for the 2024 Annual Meeting of Shareholders of M&T Bank Corporation in Parts II and III.
Common Stock [Member]
Document Information [Line Items]
Title of 12(b) Security	Common Stock, $0.50 par value
Trading Symbol	MTB
Security Exchange Name	NYSE
Series H Preferred Stock [Member]
Document Information [Line Items]
Title of 12(b) Security	Perpetual Fixed-to-Floating Rate Non-Cumulative Preferred Stock, Series H
Trading Symbol	MTBPrH
Security Exchange Name	NYSE