Subsequent event	12 Months Ended
Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent event	27. Subsequent event On February 22, 2021, M&T announced that it had entered into a definitive agreement with People’s United Financial, Inc. (“People’s United”), headquartered in Bridgeport, Connecticut, under which M&T will acquire People’s United in an all-stock transaction with a total market value of approximately $7.6 billion. Under the terms of the merger agreement, People’s United shareholders will receive 0.118 of a share of M&T common stock for each People’s United share they own. In addition, at the effective time of the merger, each outstanding share of fixed-to-floating rate non-cumulative perpetual preferred stock, Series A, of People’s United will be converted into a right to receive a share of newly created series of M&T preferred stock. The merger has been unanimously approved by the boards of directors of each company. The merger is expected to close in the fourth quarter of 2021, subject to the satisfaction of customary closing conditions, including the receipt of regulatory approvals and approval by the shareholders of M&T and People’s United. In a press release dated January 21, 2021, People’s United preliminarily reported total assets of approximately $63 billion, including loans of $44 billion, and deposits of $52 billion.

Subsequent event

12 Months Ended

Dec. 31, 2020

27. Subsequent event

On February 22, 2021, M&T announced that it had entered into a definitive agreement with People’s United Financial, Inc. (“People’s United”), headquartered in Bridgeport, Connecticut, under which M&T will acquire People’s United in an all-stock transaction with a total market value of approximately $7.6 billion. Under the terms of the merger agreement, People’s United shareholders will receive 0.118 of a share of M&T common stock for each People’s United share they own. In addition, at the effective time of the merger, each outstanding share of fixed-to-floating rate non-cumulative perpetual preferred stock, Series A, of People’s United will be converted into a right to receive a share of newly created series of M&T preferred stock.

The merger has been unanimously approved by the boards of directors of each company. The merger is expected to close in the fourth quarter of 2021, subject to the satisfaction of customary closing conditions, including the receipt of regulatory approvals and approval by the shareholders of M&T and People’s United.

In a press release dated January 21, 2021, People’s United preliminarily reported total assets of approximately $63 billion, including loans of $44 billion, and deposits of $52 billion.