Significant accounting policies and current environment	9 Months Ended
Sep. 30, 2020
Accounting Policies [Abstract]
Significant accounting policies and current environment	1. Significant accounting policies and current environment The consolidated interim financial statements of M&T Bank Corporation (“M&T”) and subsidiaries (“the Company”) were compiled in accordance with generally accepted accounting principles (“GAAP”) using the accounting policies set forth in note 1 of Notes to Financial Statements included in Form 10-K for the year ended December 31, 2019 (“2019 Annual Report”), except that effective January 1, 2020 the Company adopted accounting guidance related to the recognition of expected credit losses that is discussed in notes 2, 3 and 15 herein. The financial statements contain all adjustments which are, in the opinion of management, necessary for a fair statement of the Company’s financial position, results of operations and cash flows for the interim periods presented. The United States has been operating under a state of emergency related to the Coronavirus Disease 2019 (“COVID-19”) pandemic since March 13, 2020. The direct and indirect effects of the COVID-19 pandemic resulted in a dramatic reduction in economic activity that severely hampered the ability for businesses and consumers to meet their repayment obligations. The effects of the pandemic contributed to a significant increase in the provision for credit losses during the first nine months of 2020. The Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”), in addition to providing financial assistance to both businesses and consumers, creates a forbearance program for federally-backed mortgage loans, protects borrowers from negative credit reporting due to loan accommodations related to the national emergency, and provides financial institutions the option to temporarily suspend certain requirements under GAAP related to troubled debt restructurings to account for the effects of COVID-19. The bank regulatory agencies likewise issued guidance encouraging financial institutions to work prudently with borrowers who are, or may be, unable to meet their contractual payment obligations because of the effects of COVID-19. That guidance, with concurrence of the Financial Accounting Standards Board, and provisions of the CARES Act allow modifications made on a good faith basis in response to COVID-19 to borrowers who were generally current with their payments prior to any relief, to not be treated as troubled debt restructurings nor be reported as past due. Modifications may include payment deferrals, fee waivers, extensions of repayment term, or other delays in payment. The Company has been working with its customers affected by COVID-19 and has granted modifications across many of its loan portfolios. To the extent that such modifications meet the criteria previously described, the modified loans have not been classified as troubled debt restructurings nor reported as past due.

Significant accounting policies and current environment

9 Months Ended

Sep. 30, 2020

Significant accounting policies and current environment

1. Significant accounting policies and current environment

The consolidated interim financial statements of M&T Bank Corporation (“M&T”) and subsidiaries (“the Company”) were compiled in accordance with generally accepted accounting principles (“GAAP”) using the accounting policies set forth in note 1 of Notes to Financial Statements included in Form 10-K for the year ended December 31, 2019 (“2019 Annual Report”), except that effective January 1, 2020 the Company adopted accounting guidance related to the recognition of expected credit losses that is discussed in notes 2, 3 and 15 herein. The financial statements contain all adjustments which are, in the opinion of management, necessary for a fair statement of the Company’s financial position, results of operations and cash flows for the interim periods presented.

The United States has been operating under a state of emergency related to the Coronavirus Disease 2019 (“COVID-19”) pandemic since March 13, 2020. The direct and indirect effects of the COVID-19 pandemic resulted in a dramatic reduction in economic activity that severely hampered the ability for businesses and consumers to meet their repayment obligations. The effects of the pandemic contributed to a significant increase in the provision for credit losses during the first nine months of 2020. The Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”), in addition to providing financial assistance to both businesses and consumers, creates a forbearance program for federally-backed mortgage loans, protects borrowers from negative credit reporting due to loan accommodations related to the national emergency, and provides financial institutions the option to temporarily suspend certain requirements under GAAP related to troubled debt restructurings to account for the effects of COVID-19. The bank regulatory agencies likewise issued guidance encouraging financial institutions to work prudently with borrowers who are, or may be, unable to meet their contractual payment obligations because of the effects of COVID-19. That guidance, with concurrence of the Financial Accounting Standards Board, and provisions of the CARES Act allow modifications made on a good faith basis in response to COVID-19 to borrowers who were generally current with their payments prior to any relief, to not be treated as troubled debt restructurings nor be reported as past due. Modifications may include payment deferrals, fee waivers, extensions of repayment term, or other delays in payment. The Company has been working with its customers affected by COVID-19 and has granted modifications across many of its loan portfolios. To the extent that such modifications meet the criteria previously described, the modified loans have not been classified as troubled debt restructurings nor reported as past due.