The amount of residual value associated with direct financing leases that are guaranteed by the lessees or others.

No definition available.

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Charges incurred related to reimbursement to loan purchasers for losses incurred, or the repurchase of previously sold residential real estate loans that do not ultimately meet investor sale criteria related to underwriting procedures or loan documentation.

+ References

No definition available.

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The amount of interest income that would have been recognized if nonaccrual and renegotiated loans had been accruing interest at their originally contracted terms.

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No definition available.

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The amount of interest income that was included in earnings during the period on loans that were in nonaccrual or renegotiated status as of the end of the period.

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No definition available.

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The amount of purchased impaired loans as a percentage of total assets.

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No definition available.

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Loans and leases receivable.

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No definition available.

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Amount of loans serviced for others that were sold with recourse in conjunction with the participation in the Fannie Mae Delegated Underwriting Servicing program.

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No definition available.

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Percentage of loans in the process of foreclosure, serviced by other entities, classified as government guaranteed.

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No definition available.

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Residential mortgage loans secured by residential real estate in process of foreclosure.

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No definition available.

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Fair value at acquisition of acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition

For an unclassified balance sheet, reflects the carrying amount of unpaid loan amounts due from related parties at the balance sheet date.

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Reflects the amount of new advances made to related parties in the form of loan and lease receivables.

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Describes transactions with related parties, including directors, officers and key employees, including: (1) the aggregate amount of related party loans if they exceed 5 percent of shareholders' equity at the balance sheet date or at any time during the latest fiscal year, (2) an analysis of activity with respect to such loans for the latest fiscal year (i.e., beginning balance, new loans, repayments, other changes and ending balance), (3) the aggregate amount of any significant nonaccrual of interest, past due amounts, or restructured or potential problem (including additional information necessary to understand the impact on the financial statements), and (4) any related party loans not made in the ordinary course of business.

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- Definition

Amount of cash inflow from related parties which reduce the amount of loans and leases receivable due from related parties.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Amount, after valuation allowance, of financing receivable held for sale and not part of disposal group. Excludes loan covered under loss sharing agreement and loan classified as investment in debt security.

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Carrying amount as of the balance sheet date of other real estate and foreclosed assets. Other real estate may include real estate investments, real estate loans that qualify as investments in real estate, and premises that are no longer used in operations may also be included in real estate owned. Foreclosed assets include all assets obtained in full or partial satisfaction of a debt arrangement through foreclosure proceedings.

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The carrying amount, as of the date of the latest financial statement presented, of loans receivable which are owned but transferred to serve as collateral for the payment of FHLB debt obligations, and for which the transferee is not permitted to sell or re-pledge them to an unrelated party.

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Loans and Leases - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Loans And Leases Receivable [Line Items]
Charges incurred for reimbursement of loan	$ 0	$ 0	$ 0
Amount of foreclosed residential real estate property held	28,000,000	76,000,000
Loans secured by residential real estate that were in the process of foreclosure	$ 214,000,000	402,000,000
Percentage loans in the process of foreclosure, serviced by other entities, classified as government guaranteed	41.00%
Interest income that would have been recognized on nonaccrual and renegotiated loans if those loans were accruing interest at their originally contracted terms	$ 96,000,000	68,000,000	69,000,000
Interest on nonaccrual and renegotiated loans included in interest income	44,000,000	33,000,000	33,000,000
Contractual principal and interest payments		228,000,000	$ 228,000,000
Guaranteed amount included in the estimated residual value of leased assets associated with direct financing leases	$ 34,000,000	$ 37,000,000
Maximum [Member]
Loans And Leases Receivable [Line Items]
Purchased impaired loans as a percentage of total assets		1.00%	1.00%
Director and Certain Officers [Member]
Loans And Leases Receivable [Line Items]
Exclusion limit of loans from related party disclosure	less than $60,000
Borrowing by directors and certain officers of M&T and its banking subsidiaries and their associates	$ 72,000,000	$ 28,000,000
New borrowings by directors, certain officers and their associates	46,000,000
Repayments and other reductions of borrowings by directors, certain officers and their associates	2,000,000
Commercial Real Estate [Member]
Loans And Leases Receivable [Line Items]
Loans serviced for others sold with credit recourse	4,000,000,000.0
Loans pledged to secure outstanding borrowings from the FHLB of New York	13,700,000,000
Residential Mortgage Loans [Member]
Loans And Leases Receivable [Line Items]
Loans pledged to secure outstanding borrowings from the FHLB of New York	12,900,000,000
Residential Mortgage Loans [Member] \| One-to-Four Family Residential [Member]
Loans And Leases Receivable [Line Items]
Mortgage loans held for sale	777,000,000	414,000,000
Commercial Real Estate Loans [Member] \| One-to-Four Family Residential [Member]
Loans And Leases Receivable [Line Items]
Mortgage loans held for sale	278,000,000	$ 28,000,000
Commercial Loans and Leases [Member]
Loans And Leases Receivable [Line Items]
Loans pledged to secure outstanding borrowings from the FHLB of New York	10,200,000,000
Home Equity Loans and Lines of Credit [Member]
Loans And Leases Receivable [Line Items]
Loans pledged to secure outstanding borrowings from the FHLB of New York	2,100,000,000
Other Consumer Loans [Member]
Loans And Leases Receivable [Line Items]
Loans pledged to secure outstanding borrowings from the FHLB of New York	$ 8,500,000,000