M&T Bank (MTB) 10-K 22 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 17, 2017	Jun. 30, 2016
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Trading Symbol	MTB
Entity Registrant Name	M&T BANK CORP
Entity Central Index Key	36,270
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		154,172,084
Entity Public Float			$ 16,919,525,595

Consolidated Balance Sheet

Consolidated Balance Sheet - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets
Cash and due from banks	$ 1,320,549	$ 1,368,040
Interest-bearing deposits at banks	5,000,638	7,594,350
Trading account	323,867	273,783
Investment securities (includes pledged securities that can be sold or repledged of $1,203,473 at December 31, 2016; $2,136,712 at December 31, 2015)
Available for sale (cost: $13,338,301 at December 31, 2016; $12,138,636 at December 31, 2015)	13,332,072	12,242,671
Held to maturity (fair value: $2,451,222 at December 31, 2016; $2,864,147 at December 31, 2015)	2,457,278	2,859,709
Other (fair value: $461,118 at December 31, 2016; $554,059 at December 31, 2015)	461,118	554,059
Total investment securities	16,250,468	15,656,439
Loans and leases	91,101,677	87,719,234
Unearned discount	(248,261)	(229,735)
Loans and leases, net of unearned discount	90,853,416	87,489,499
Allowance for credit losses	(988,997)	(955,992)
Loans and leases, net	89,864,419	86,533,507
Premises and equipment	675,263	666,682
Goodwill	4,593,112	4,593,112
Core deposit and other intangible assets	97,655	140,268
Accrued interest and other assets	5,323,235	5,961,703
Total assets	123,449,206	122,787,884
Liabilities
Noninterest-bearing deposits	32,813,896	29,110,635
Savings and interest-checking deposits	52,346,207	49,566,644
Time deposits	10,131,846	13,110,392
Deposits at Cayman Islands office	201,927	170,170
Total deposits	95,493,876	91,957,841
Federal funds purchased and agreements to repurchase securities	163,442	150,546
Other short-term borrowings		1,981,636
Accrued interest and other liabilities	1,811,431	1,870,714
Long-term borrowings	9,493,835	10,653,858
Total liabilities	106,962,584	106,614,595
Shareholders' equity
Preferred stock, $1.00 par, 1,000,000 shares authorized; Issued and outstanding: Liquidation preference of $1,000 per share: 731,500 shares at December 31, 2016 and December 31, 2015; Liquidation preference of $10,000 per share: 50,000 shares at December 31, 2016 and December 31, 2015	1,231,500	1,231,500
Common stock, $.50 par, 250,000,000 shares authorized, 159,945,678 shares issued at December 31, 2016; 159,563,512 shares issued at December 31, 2015	79,973	79,782
Common stock issuable, 32,403 shares at December 31, 2016; 36,644 shares at December 31, 2015	2,145	2,364
Additional paid-in capital	6,676,948	6,680,768
Retained earnings	9,222,488	8,430,502
Accumulated other comprehensive income (loss), net	(294,636)	(251,627)
Treasury stock - common, at cost - 3,764,742 shares at December 31, 2016	(431,796)
Total shareholders’ equity	16,486,622	16,173,289
Total liabilities and shareholders’ equity	$ 123,449,206	$ 122,787,884

Consolidated Balance Sheet (Par

Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Pledged securities that can be sold or repledged	$ 1,203,473	$ 2,136,712
Investment securities, available for sale, amortized cost	13,338,301	12,138,636
Investment securities, held to maturity, fair value	2,451,222	2,864,147
Other, fair value	$ 461,118	$ 554,059
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	1,000,000	1,000,000
Common stock, par value	$ 0.50	$ 0.50
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	159,945,678	159,563,512
Common stock issuable, shares	32,403	36,644
Treasury stock, shares	3,764,742
Series A and Series C [Member]
Preferred stock, shares issued	731,500	731,500
Preferred stock, shares outstanding	731,500	731,500
Preferred stock, liquidation preference per share	$ 1,000	$ 1,000
Series D Preferred Stock [Member]
Preferred stock, shares issued	50,000	50,000
Preferred stock, shares outstanding	50,000	50,000
Preferred stock, liquidation preference per share	$ 10,000	$ 10,000

Consolidated Statement of Incom

Consolidated Statement of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Interest income
Loans and leases, including fees	$ 3,485,050	$ 2,778,151	$ 2,596,586
Investment securities
Fully taxable	361,494	372,162	340,391
Exempt from federal taxes	2,606	4,263	5,356
Deposits at banks	45,516	15,252	13,361
Other	1,205	1,016	1,183
Total interest income	3,895,871	3,170,844	2,956,877
Interest expense
Savings and interest-checking deposits	87,704	46,140	46,869
Time deposits	102,841	27,059	15,515
Deposits at Cayman Islands office	797	615	699
Short-term borrowings	3,625	1,677	101
Long-term borrowings	231,017	252,766	217,247
Total interest expense	425,984	328,257	280,431
Net interest income	3,469,887	2,842,587	2,676,446
Provision for credit losses	190,000	170,000	124,000
Net interest income after provision for credit losses	3,279,887	2,672,587	2,552,446
Other income
Mortgage banking revenues	373,697	375,738	362,912
Service charges on deposit accounts	419,102	420,608	427,956
Trust income	472,184	470,640	508,258
Brokerage services income	63,423	64,770	67,212
Trading account and foreign exchange gains	41,126	30,577	29,874
Gain (loss) on bank investment securities	30,314	(130)
Other revenues from operations	426,150	462,834	383,061
Total other income	1,825,996	1,825,037	1,779,273
Other expense
Salaries and employee benefits	1,623,600	1,549,530	1,404,950
Equipment and net occupancy	295,141	272,539	269,299
Outside data processing and software	172,389	164,133	151,568
FDIC assessments	105,045	52,113	55,531
Advertising and marketing	87,137	59,227	47,111
Printing, postage and supplies	39,546	38,491	38,201
Amortization of core deposit and other intangible assets	42,613	26,424	33,824
Other costs of operations	682,014	660,475	688,990
Total other expense	3,047,485	2,822,932	2,689,474
Income before taxes	2,058,398	1,674,692	1,642,245
Income taxes	743,284	595,025	575,999
Net income	1,315,114	1,079,667	1,066,246
Net income available to common shareholders
Basic	1,223,459	987,689	978,531
Diluted	$ 1,223,481	$ 987,724	$ 978,581
Net income per common share
Basic	$ 7.80	$ 7.22	$ 7.47
Diluted	$ 7.78	$ 7.18	$ 7.42

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Partners Capital [Abstract]
Net income	$ 1,315,114	$ 1,079,667	$ 1,066,246
Other comprehensive income (loss), net of tax and reclassification adjustments:
Net unrealized gains (losses) on investment securities	(64,406)	(79,114)	93,275
Cash flow hedges adjustments	(94)	796	(96)
Foreign currency translation adjustment	(2,614)	(925)	(2,607)
Defined benefit plans liability adjustments	24,105	8,610	(207,407)
Total other comprehensive loss	(43,009)	(70,633)	(116,835)
Total comprehensive income	$ 1,272,105	$ 1,009,034	$ 949,411

Consolidated Statement of Cash

Consolidated Statement of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities
Net income	$ 1,315,114	$ 1,079,667	$ 1,066,246
Adjustments to reconcile net income to net cash provided by operating activities
Provision for credit losses	190,000	170,000	124,000
Depreciation and amortization of premises and equipment	106,996	99,019	96,496
Amortization of capitalized servicing rights	50,982	49,906	68,410
Amortization of core deposit and other intangible assets	42,613	26,424	33,824
Provision for deferred income taxes	174,013	396,596	92,848
Asset write-downs	21,036	9,029	6,593
Net gain on sales of assets	(63,222)	(67,759)	(6,859)
Net change in accrued interest receivable, payable	(12,282)	(46,338)	15,163
Net change in other accrued income and expense	60,263	(289,139)	(68,722)
Net change in loans originated for sale	(665,649)	323,330	(350,581)
Net change in trading account assets and liabilities	(36,453)	(8,327)	21,623
Net cash provided by operating activities	1,183,411	1,742,408	1,099,041
Cash flows from investing activities
Proceeds from sales of investment securities Available for sale	63,513	5,654,850	16
Proceeds from sales of investment securities Other	94,749	183,892	23,445
Proceeds from maturities of investment securities Available for sale	2,309,208	2,392,331	998,413
Proceeds from maturities of investment securities Held to maturity	609,080	662,959	468,999
Purchases of investment securities Available for sale	(3,562,711)	(3,614,324)	(5,347,145)
Purchases of investment securities Held to maturity	(214,791)	(29,431)	(21,283)
Purchases of investment securities Other	(1,808)	(99,317)	(53,606)
Net increase in loans and leases	(2,952,129)	(2,326,744)	(2,421,162)
Net (increase) decrease in interest-bearing deposits at banks	2,593,712	6,445,451	(4,819,729)
Capital expenditures, net	(107,693)	(81,936)	(73,161)
Net (increase) decrease in loan servicing advances	170,141	448,271	(484,689)
Acquisition of bank and bank holding company, net of cash acquired		(1,932,596)
Other, net	277,961	10,876	19,531
Net cash provided (used) by investing activities	(720,768)	7,714,282	(11,710,371)
Cash flows from financing activities
Net increase in deposits	3,554,673	504,393	6,466,697
Net decrease in short-term borrowings	(1,937,105)	(2,167,405)	(67,779)
Proceeds from long-term borrowings		1,500,000	4,345,478
Payments on long-term borrowings	(1,119,898)	(8,912,474)	(426,275)
Purchases of treasury stock	(641,334)
Dividends paid — common	(441,891)	(375,017)	(371,199)
Dividends paid — preferred	(81,270)	(81,270)	(70,234)
Redemption of Series D preferred stock	(500,000)
Proceeds from issuance of preferred stock	495,000		346,500
Other, net	161,691	69,766	88,565
Net cash provided (used) by financing activities	(510,134)	(9,462,007)	10,311,753
Net increase (decrease) in cash and cash equivalents	(47,491)	(5,317)	(299,577)
Cash and cash equivalents at beginning of year	1,368,040	1,373,357	1,672,934
Cash and cash equivalents at end of year	1,320,549	1,368,040	1,373,357
Supplemental disclosure of cash flow information
Interest received during the year	3,903,374	3,134,311	2,893,153
Interest paid during the year	498,951	400,329	257,553
Income taxes paid during the year	276,866	378,660	411,912
Supplemental schedule of noncash investing and financing activities
Real estate acquired in settlement of loans	124,033	67,753	43,821
Acquisition of bank and bank holding company
Common stock issued		3,110,581
Common stock awards converted		28,243
Fair value of Assets acquired (noncash)		36,567,632
Fair value of Liabilities assumed		31,496,212
Securitization of residential mortgage loans allocated to Available-for-sale investment securities	24,233	65,023	134,698
Securitization of residential mortgage loans allocated to Capitalized servicing rights	$ 248	$ 646	$ 1,760

Consolidated Statement of Chang

Consolidated Statement of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Series E Preferred Stock [Member]	Series D Preferred Stock [Member]	Series F Preferred Stock [Member]	Series A Warrants [Member]	Preferred Stock [Member]	Preferred Stock [Member]Series E Preferred Stock [Member]	Preferred Stock [Member]Series D Preferred Stock [Member]	Preferred Stock [Member]Series F Preferred Stock [Member]	Common Stock [Member]	Common Stock [Member]Series A Warrants [Member]	Common Stock Issuable [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member]Series E Preferred Stock [Member]	Additional Paid-in Capital [Member]Series F Preferred Stock [Member]	Additional Paid-in Capital [Member]Series A Warrants [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss), Net [Member]	Treasury Stock [Member]	Treasury Stock [Member]Series A Warrants [Member]
Beginning balance at Dec. 31, 2013	$ 11,305,532					$ 881,500				$ 65,258		$ 2,915	$ 3,232,014				$ 7,188,004	$ (64,159)
Total comprehensive income	949,411																1,066,246	(116,835)
Preferred stock cash dividends	(75,878)																(75,878)
Issuance of preferred stock		$ 346,500					$ 350,000							$ (3,500)
Exercise of stock warrants into common stock											$ 85					$ (85)
Stock-based compensation plans:
Compensation expense, net	45,434									128			45,306
Exercises of stock options, net	123,109									633			122,476
Stock purchase plan	9,588									43			9,545
Directors’ stock plan	1,665									7			1,658
Deferred compensation plans, net, including dividend equivalents	(75)									3		(307)	345				(116)
Other	1,747												1,747
Common stock cash dividends - $2.80 per share	(371,137)																(371,137)
Ending balance at Dec. 31, 2014	12,335,896					1,231,500				66,157		2,608	3,409,506				7,807,119	(180,994)
Total comprehensive income	1,009,034																1,079,667	(70,633)
Acquisition of Hudson City Bancorp, Inc, common stock issued	3,110,581									12,977			3,097,604
Acquisition of Hudson City Bancorp, Inc, common stock awards converted	28,243												28,243
Preferred stock cash dividends	(81,270)																(81,270)
Exercise of stock warrants into common stock											$ 1					(1)
Stock-based compensation plans:
Compensation expense, net	43,195									155			43,040
Exercises of stock options, net	88,893									438			88,455
Stock purchase plan	10,346									45			10,301
Directors’ stock plan	1,761									7			1,754
Deferred compensation plans, net, including dividend equivalents	(51)									2		(244)	293				(102)
Other	1,573												1,573
Common stock cash dividends - $2.80 per share	(374,912)																(374,912)
Ending balance at Dec. 31, 2015	16,173,289					1,231,500				79,782		2,364	6,680,768				8,430,502	(251,627)
Total comprehensive income	1,272,105																1,315,114	(43,009)
Preferred stock cash dividends	(81,270)																(81,270)
Redemption of Series D preferred stock			$ (500,000)					$ (500,000)
Issuance of preferred stock				$ 495,000					$ 500,000						$ (5,000)
Exercise of stock warrants into common stock					$ (2)											$ (4,750)				$ 4,748
Purchases of treasury stock	(641,334)																		$ (641,334)
Stock-based compensation plans:
Compensation expense, net	27,290									169			16,132						10,989
Exercises of stock options, net	169,617									18			(12,190)						181,789
Stock purchase plan	10,594												275						10,319
Directors’ stock plan	2,080									2			535						1,543
Deferred compensation plans, net, including dividend equivalents	3									2		(219)	163				(93)		150
Other	1,015												1,015
Common stock cash dividends - $2.80 per share	(441,765)																(441,765)
Ending balance at Dec. 31, 2016	$ 16,486,622					$ 1,231,500				$ 79,973		$ 2,145	$ 6,676,948				$ 9,222,488	$ (294,636)	$ (431,796)

Consolidated Statement of Chan8

Consolidated Statement of Changes in Shareholders' Equity (Parenthetical) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Common Stock [Member] | Series A Warrants [Member]
Exercise of warrants into shares of common stock		2,315	427,905
Exercise of warrants into shares of common stock		904	169,543
Retained Earnings [Member]
Common stock per share dividend amount	$ 2.80	$ 2.80	$ 2.80
Treasury Stock [Member] | Series A Warrants [Member]
Exercise of warrants into shares of common stock	87,381
Exercise of warrants into shares of common stock	41,439

Significant accounting policies

Significant accounting policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Significant accounting policies	1. Significant accounting policies M&T Bank Corporation (“M&T”) is a bank holding company headquartered in Buffalo, New York. Through subsidiaries, M&T provides individuals, corporations and other businesses, and institutions with commercial and retail banking services, including loans and deposits, trust, mortgage banking, asset management, insurance and other financial services. Banking activities are largely focused on consumers residing in New York State, Maryland, New Jersey, Pennsylvania, Delaware, Connecticut, Virginia, West Virginia and the District of Columbia and on small and medium-size businesses based in those areas. Certain subsidiaries also conduct activities in other areas. The accounting and reporting policies of M&T and subsidiaries (“the Company”) are in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and to general practices within the banking industry. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The more significant accounting policies are as follows: Consolidation The consolidated financial statements include M&T and all of its subsidiaries. All significant intercompany accounts and transactions of consolidated subsidiaries have been eliminated in consolidation. The financial statements of M&T included in note 25 report investments in subsidiaries under the equity method. Information about some limited purpose entities that are affiliates of the Company but are not included in the consolidated financial statements appears in note 19. Consolidated Statement of Cash Flows For purposes of this statement, cash and due from banks and federal funds sold are considered cash and cash equivalents. Securities purchased under agreements to resell and securities sold under agreements to repurchase Securities purchased under agreements to resell and securities sold under agreements to repurchase are treated as collateralized financing transactions and are recorded at amounts equal to the cash or other consideration exchanged. It is generally the Company’s policy to take possession of collateral pledged to secure agreements to resell. Trading account Financial instruments used for trading purposes are stated at fair value. Realized gains and losses and unrealized changes in fair value of financial instruments utilized in trading activities are included in “trading account and foreign exchange gains” in the consolidated statement of income. Investment securities Investments in debt securities are classified as held to maturity and stated at amortized cost when management has the positive intent and ability to hold such securities to maturity. Investments in other debt securities and equity securities having readily determinable fair values are classified as available for sale and stated at estimated fair value. Amortization of premiums and accretion of discounts for investment securities available for sale and held to maturity are included in interest income. Other securities are stated at cost and include stock of the Federal Reserve Bank of New York and the Federal Home Loan Bank (“FHLB”) of New York. The cost basis of individual securities is written down through a charge to earnings when declines in value below amortized cost are considered to be other than temporary. In cases where fair value is less than amortized cost and the Company intends to sell a debt security, it is more likely than not to be required to sell a debt security before recovery of its amortized cost basis, or the Company does not expect to recover the entire amortized cost basis of a debt security, an other-than-temporary impairment is considered to have occurred. If the Company intends to sell the debt security or more likely than not will be required to sell the security before recovery of its amortized cost basis, the other-than-temporary impairment is recognized in earnings equal to the entire difference between the debt security’s amortized cost basis and its fair value. If the Company does not expect to recover the entire amortized cost basis of the security, the Company does not intend to sell the security and it is not more likely than not that the Company will be required to sell the security before recovery of its amortized cost basis, the other-than-temporary impairment is separated into (a) the amount representing the credit loss and (b) the amount related to all other factors. The amount of the other-than-temporary impairment related to the credit loss is recognized in earnings while the amount related to other factors is recognized in other comprehensive income, net of applicable taxes. Subsequently, the Company accounts for the other-than-temporarily impaired debt security as if the security had been purchased on the measurement date of the other-than-temporary impairment at an amortized cost basis equal to the previous amortized cost basis less the other-than-temporary impairment recognized in earnings. The cost basis of individual equity securities is written down to estimated fair value through a charge to earnings when declines in value below cost are considered to be other than temporary. Realized gains and losses on the sales of investment securities are determined using the specific identification method. Loans and leases The Company’s accounting methods for loans depends on whether the loans were originated by the Company or were acquired in a business combination. Originated loans and leases Interest income on loans is accrued on a level yield method. Loans are placed on nonaccrual status and previously accrued interest thereon is charged against income when principal or interest is delinquent 90 days, unless management determines that the loan status clearly warrants other treatment. Nonaccrual commercial loans and commercial real estate loans are returned to accrual status when borrowers have demonstrated an ability to repay their loans and there are no delinquent principal and interest payments. Consumer loans not secured by residential real estate are returned to accrual status when all past due principal and interest payments have been paid by the borrower. Loans secured by residential real estate are returned to accrual status when they are deemed to have an insignificant delay in payments of 90 days or less. Loan balances are charged off when it becomes evident that such balances are not fully collectible. For commercial loans and commercial real estate loans, charge-offs are recognized after an assessment by credit personnel of the capacity and willingness of the borrower to repay, the estimated value of any collateral, and any other potential sources of repayment. A charge-off is recognized when, after such assessment, it becomes evident that the loan balance is not fully collectible. For loans secured by residential real estate, the excess of the loan balances over the net realizable value of the property collateralizing the loan is charged-off when the loan becomes 150 days delinquent. Consumer loans are generally charged-off when the loans are 91 to 180 days past due, depending on whether the loan is collateralized and the status of repossession activities with respect to such collateral. Loan fees and certain direct loan origination costs are deferred and recognized as an interest yield adjustment over the life of the loan. Net deferred fees have been included in unearned discount as a reduction of loans outstanding. Commitments to sell real estate loans are utilized by the Company to hedge the exposure to changes in fair value of real estate loans held for sale. The carrying value of hedged real estate loans held for sale recorded in the consolidated balance sheet includes changes in estimated fair market value during the hedge period, typically from the date of close through the sale date. Valuation adjustments made on these loans and commitments are included in “mortgage banking revenues.” Except for consumer and residential mortgage loans that are considered smaller balance homogenous loans and are evaluated collectively, the Company considers a loan to be impaired for purposes of applying GAAP when, based on current information and events, it is probable that the Company will be unable to collect all amounts according to the contractual terms of the loan agreement or the loan is delinquent 90 days. Regardless of loan type, the Company considers a loan to be impaired if it qualifies as a troubled debt restructuring. Impaired loans are classified as either nonaccrual or as loans renegotiated at below market rates which continue to accrue interest, provided that a credit assessment of the borrower’s financial condition results in an expectation of full repayment under the modified contractual terms. Certain loans greater than 90 days delinquent are not considered impaired if they are well-secured and in the process of collection. Loans less than 90 days delinquent are deemed to have an insignificant delay in payment and are generally not considered impaired. Impairment of a loan is measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate, the loan’s observable market price, or the fair value of collateral if the loan is collateral-dependent. Interest received on impaired loans placed on nonaccrual status is generally applied to reduce the carrying value of the loan or, if principal is considered fully collectible, recognized as interest income. Residual value estimates for commercial leases are generally determined through internal or external reviews of the leased property. The Company reviews commercial lease residual values at least annually and recognizes residual value impairments deemed to be other than temporary. Loans and leases acquired in a business combination Loans acquired in a business combination subsequent to December 31, 2008 are initially recorded at fair value with no carry-over of an acquired entity’s previously established allowance for credit losses. Purchased impaired loans represent specifically identified loans with evidence of credit deterioration for which it was probable at acquisition that the Company would be unable to collect all contractual principal and interest payments. For purchased impaired loans and other loans acquired at a discount that was, in part, attributable to credit quality, the excess of cash flows expected at acquisition over the estimated fair value of acquired loans is recognized as interest income over the remaining lives of the loans. Subsequent decreases in the expected principal cash flows require the Company to evaluate the need for additions to the Company’s allowance for credit losses. Subsequent improvements in expected cash flows result first in the recovery of any related allowance for credit losses and then in recognition of additional interest income over the then-remaining lives of the loans. For all other acquired loans, the difference between the fair value and outstanding principal balance of the loans is recognized as an adjustment to interest income over the lives of those loans. Those loans are then accounted for in a manner that is similar to originated loans. Allowance for credit losses The allowance for credit losses represents, in management’s judgment, the amount of losses inherent in the loan and lease portfolio as of the balance sheet date. The allowance is determined by management’s evaluation of the loan and lease portfolio based on such factors as the differing economic risks associated with each loan category, the current financial condition of specific borrowers, the economic environment in which borrowers operate, the level of delinquent loans, the value of any collateral and, where applicable, the existence of any guarantees or indemnifications. The effects of probable decreases in expected principal cash flows on loans acquired at a discount are also considered in the establishment of the allowance for credit losses. Assets taken in foreclosure of defaulted loans Assets taken in foreclosure of defaulted loans are primarily comprised of commercial and residential real property and are included in “other assets” in the consolidated balance sheet. An in-substance repossession or foreclosure occurs and a creditor is considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan upon either (1) the creditor obtaining legal title to the residential real estate property upon completion of a foreclosure or (2) the borrower conveying all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. Upon acquisition of assets taken in satisfaction of a defaulted loan, the excess of the remaining loan balance over the asset’s estimated fair value less costs to sell is charged-off against the allowance for credit losses. Subsequent declines in value of the assets are recognized as “other costs of operations” in the consolidated statement of income. Premises and equipment Premises and equipment are stated at cost less accumulated depreciation. Depreciation expense is computed principally using the straight-line method over the estimated useful lives of the assets. Capitalized servicing rights Capitalized servicing assets are included in “other assets” in the consolidated balance sheet. Separately recognized servicing assets are initially measured at fair value. The Company uses the amortization method to subsequently measure servicing assets. Under that method, capitalized servicing assets are charged to expense in proportion to and over the period of estimated net servicing income. To estimate the fair value of servicing rights, the Company considers market prices for similar assets and the present value of expected future cash flows associated with the servicing rights calculated using assumptions that market participants would use in estimating future servicing income and expense. Such assumptions include estimates of the cost of servicing loans, loan default rates, an appropriate discount rate, and prepayment speeds. For purposes of evaluating and measuring impairment of capitalized servicing rights, the Company stratifies such assets based on the predominant risk characteristics of the underlying financial instruments that are expected to have the most impact on projected prepayments, cost of servicing and other factors affecting future cash flows associated with the servicing rights. Such factors may include financial asset or loan type, note rate and term. The amount of impairment recognized is the amount by which the carrying value of the capitalized servicing rights for a stratum exceeds estimated fair value. Impairment is recognized through a valuation allowance. Sales and securitizations of financial assets Transfers of financial assets for which the Company has surrendered control of the financial assets are accounted for as sales. Interests in a sale of financial assets that continue to be held by the Company, including servicing rights, are measured at fair value. The fair values of retained debt securities are generally determined through reference to independent pricing information. The fair values of retained servicing rights and any other retained interests are determined based on the present value of expected future cash flows associated with those interests and by reference to market prices for similar assets. Securitization structures typically require the use of special-purpose trusts that are considered variable interest entities. A variable interest entity is included in the consolidated financial statements if the Company has the power to direct the activities that most significantly impact the variable interest entity’s economic performance and has the obligation to absorb losses or the right to receive benefits of the variable interest entity that could potentially be significant to that entity. Goodwill and core deposit and other intangible assets Goodwill represents the excess of the cost of an acquired entity over the fair value of the identifiable net assets acquired. Goodwill is not amortized, but rather is tested for impairment at least annually at the reporting unit level, which is either at the same level or one level below an operating segment. Other acquired intangible assets with finite lives, such as core deposit intangibles, are initially recorded at estimated fair value and are amortized over their estimated lives. Core deposit and other intangible assets are generally amortized using accelerated methods over estimated useful lives of five to ten years. The Company periodically assesses whether events or changes in circumstances indicate that the carrying amounts of core deposit and other intangible assets may be impaired. Derivative financial instruments The Company accounts for derivative financial instruments at fair value. If certain conditions are met, a derivative may be specifically designated as (a) a hedge of the exposure to changes in the fair value of a recognized asset or liability or an unrecognized firm commitment, (b) a hedge of the exposure to variable cash flows of a forecasted transaction or (c) a hedge of the foreign currency exposure of a net investment in a foreign operation, an unrecognized firm commitment, an available-for-sale security, or a foreign currency denominated forecasted transaction. The Company utilizes interest rate swap agreements as part of the management of interest rate risk to modify the repricing characteristics of certain portions of its portfolios of earning assets and interest-bearing liabilities. For such agreements, amounts receivable or payable are recognized as accrued under the terms of the agreement and the net differential is recorded as an adjustment to interest income or expense of the related asset or liability. Interest rate swap agreements may be designated as either fair value hedges or cash flow hedges. In a fair value hedge, the fair values of the interest rate swap agreements and changes in the fair values of the hedged items are recorded in the Company’s consolidated balance sheet with the corresponding gain or loss recognized in current earnings. The difference between changes in the fair values of interest rate swap agreements and the hedged items represents hedge ineffectiveness and is recorded in “other revenues from operations” in the consolidated statement of income. In a cash flow hedge, the effective portion of the derivative’s unrealized gain or loss is initially recorded as a component of other comprehensive income and subsequently reclassified into earnings when the forecasted transaction affects earnings. The ineffective portion of the unrealized gain or loss is reported in “other revenues from operations” immediately. The Company utilizes commitments to sell real estate loans to hedge the exposure to changes in the fair value of real estate loans held for sale. Commitments to originate real estate loans to be held for sale and commitments to sell real estate loans are generally recorded in the consolidated balance sheet at estimated fair value. Derivative instruments not related to mortgage banking activities, including financial futures commitments and interest rate swap agreements, that do not satisfy the hedge accounting requirements are recorded at fair value and are generally classified as trading account assets or liabilities with resultant changes in fair value being recognized in “trading account and foreign exchange gains” in the consolidated statement of income. Stock-based compensation Stock-based compensation expense is recognized over the vesting period of the stock-based grant based on the estimated grant date value of the stock-based compensation, except that the recognition of compensation costs is accelerated for stock-based awards granted to retirement-eligible employees and employees who will become retirement-eligible prior to full vesting of the award because the Company’s incentive compensation plan allows for vesting at the time an employee retires. Income taxes Deferred tax assets and liabilities are recognized for the future tax effects attributable to differences between the financial statement value of existing assets and liabilities and their respective tax bases and carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates and laws. The Company evaluates uncertain tax positions using the two-step process required by GAAP. The first step requires a determination of whether it is more likely than not that a tax position will be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. Under the second step, a tax position that meets the more-likely-than-not recognition threshold is measured at the largest amount of benefit that is greater than fifty percent likely of being realized upon ultimate settlement. The Company accounts for its investments in qualified affordable housing projects using the proportional amortization method. Under that method, the Company amortizes the initial cost of the investment in proportion to the tax credits and other tax benefits received and recognizes the net investment performance in the income statement as a component of income tax expense. Earnings per common share Basic earnings per common share exclude dilution and are computed by dividing income available to common shareholders by the weighted-average number of common shares outstanding (exclusive of shares represented by the unvested portion of restricted stock and restricted stock unit grants) and common shares issuable under deferred compensation arrangements during the period. Diluted earnings per common share reflect shares represented by the unvested portion of restricted stock and restricted stock unit grants and the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock or resulted in the issuance of common stock that then shared in earnings. Proceeds assumed to have been received on such exercise or conversion are assumed to be used to purchase shares of M&T common stock at the average market price during the period, as required by the “treasury stock method” of accounting. GAAP requires that unvested share-based payment awards that contain nonforfeitable rights to dividends or dividend equivalents (whether paid or unpaid) shall be considered participating securities and shall be included in the computation of earnings per common share pursuant to the two-class method. The Company has issued stock-based compensation awards in the form of restricted stock and restricted stock units that contain such rights and, accordingly, the Company’s earnings per common share are calculated using the two-class method. Treasury stock Repurchases of shares of M&T common stock are recorded at cost as a reduction of shareholders’ equity. Reissuances of shares of treasury stock are recorded at average cost.

Acquisition and divestiture

Acquisition and divestiture	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Acquisition and divestiture	2. Acquisition and divestiture Hudson City Bancorp, Inc. On November 1, 2015, M&T completed the acquisition of Hudson City Bancorp, Inc. (“Hudson City”), headquartered in Paramus, New Jersey. On that date, Hudson City Savings Bank, the banking subsidiary of Hudson City, was merged into M&T Bank, a wholly owned banking subsidiary of M&T. Hudson City Savings Bank operated 135 banking offices in New Jersey, Connecticut and New York at the date of acquisition. The results of operations acquired in the Hudson City transaction have been included in the Company’s financial results since November 1, 2015. After application of the election, allocation and proration procedures contained in the merger agreement with Hudson City, M&T paid $2.1 billion in cash and issued 25,953,950 shares of M&T common stock in exchange for Hudson City shares outstanding at the time of the acquisition. The purchase price was approximately $5.2 billion based on the cash paid to Hudson City shareholders, the fair value of M&T stock exchanged and the estimated fair value of Hudson City stock awards converted into M&T stock awards. The acquisition of Hudson City expanded the Company’s presence in New Jersey, Connecticut and New York, and management expects that the Company will benefit from greater geographic diversity and the advantages of scale associated with a larger company. The Hudson City transaction was accounted for using the acquisition method of accounting and, accordingly, assets acquired, liabilities assumed and consideration exchanged were recorded at estimated fair value on the acquisition date. The consideration paid for Hudson City’s common equity and the amounts of identifiable assets acquired and liabilities assumed as of the acquisition date were as follows: (In thousands) Identifiable assets: Cash and due from banks $ 131,688 Interest-bearing deposits at banks 7,568,934 Investment securities 7,929,014 Loans 19,015,013 Goodwill 1,079,787 Core deposit intangible 131,665 Other assets 843,219 Total identifiable assets 36,699,320 Liabilities: Deposits 17,879,589 Borrowings 13,211,598 Other liabilities 405,025 Total liabilities 31,496,212 Total consideration $ 5,203,108 Cash paid $ 2,064,284 Common stock issued (25,953,950 shares) 3,110,581 Common stock awards converted 28,243 Total consideration $ 5,203,108 In early November 2015, the Company sold $5.8 billion of investment securities obtained in the acquisition and repaid $10.6 billion of borrowings assumed in the transaction. In connection with the acquisition, the Company recorded approximately $1.1 billion of goodwill and $132 million of core deposit intangible. The core deposit intangible asset is being amortized over a period of seven years using an accelerated method. In many cases, determining the fair value of the acquired assets and assumed liabilities required the Company to estimate cash flows expected to result from those assets and liabilities and to discount those cash flows at appropriate rates of interest. The most significant of these determinations related to the fair valuation of acquired loans. Approximately $688 million of the loans acquired from Hudson City had specific evidence of credit deterioration at the acquisition date and it was deemed probable that the Company would be unable to collect all contractually required principal and interest payments (“purchased impaired loans”). Such loans were acquired at a discount from outstanding customer principal balance of $1.0 billion. For purchased impaired loans, the excess of cash flows expected at acquisition over the estimated fair value is recognized as interest income over the remaining lives of the loans. The difference between contractually required payments at acquisition and the cash flows expected to be collected at acquisition, as shown in the following table, reflected the impact of estimated credit losses and other factors, such as prepayments. November 1, 2015 (In thousands) Contractually required principal and interest at acquisition $ 1,304,366 Contractual cash flows not expected to be collected (498,919 ) Expected cash flows at acquisition 805,447 Interest component of expected cash flows (117,251 ) Estimated fair value $ 688,196 The remaining acquired loans had a fair value of $18.3 billion and outstanding principal of $18.0 billion, resulting in a premium which will be amortized over the remaining lives of the loans as a reduction of interest income. In accordance with GAAP, there was no carry-over of Hudson City’s previously established allowance for credit losses. The following table discloses the impact of Hudson City since the acquisition on November 1, 2015 through the end of 2015. The table also presents certain pro forma information as if Hudson City had been acquired on January 1, 2014. These results combine the historical results of Hudson City into the Company’s consolidated statement of income and, while certain adjustments were made for the estimated impact of certain fair valuation adjustments and other acquisition-related activity, they are not indicative of what would have occurred had the acquisition taken place on the indicated date. In particular, no adjustments have been made to eliminate the impact of gains on securities transactions of $102 million in 2015 and $104 million in 2014 that may not have been recognized had the investment securities been recorded at fair value as of the beginning of 2014. Furthermore, expenses related to systems conversions and other costs of integration of $97 million are included in the 2015 periods in which such costs were incurred. Additionally, the Company expects to achieve further operating cost savings and other business synergies as a result of the acquisition which are not reflected in the pro forma amounts that follow. Actual Since Acquisition Through Pro Forma December 31, Year Ended December 31 2015 2015 2014 (In thousands) Total revenues(a) $ 111,168 $ 5,132,662 $ 5,406,291 Net income (loss) (21,175 ) 1,011,463 1,445,779 (a) Represents net interest income plus other income. In connection with the Hudson City acquisition, the Company incurred merger-related expenses related to systems conversions and other costs of integrating and conforming acquired operations with and into the Company. Those expenses consisted largely of professional services and other temporary help fees associated with preparing for systems conversions and/or integration of operations; costs related to termination of existing contractual arrangements for various services; initial marketing and promotion expenses designed to introduce M&T Bank to its new customers; severance (for former Hudson City employees); travel costs; and other costs of completing the transaction and commencing operations in new markets and offices. There were no merger-related expenses during 2014. In 2015, the Company also recognized a $21 million provision for credit losses related to the $18.3 billion of Hudson City loans acquired at a premium. GAAP does not allow the credit loss component of the net premium associated with those loans to be bifurcated and accounted for as a nonaccreting difference as is the case with purchased impaired loans and other loans acquired at a discount. Neverthless, GAAP requires that an allowance for credit losses be recognized for incurred losses in loans acquired at a premium even though in a relatively homogenous portfolio of residential mortgage loans the specific loans to which the losses relate cannot be individually identified at the acquisition date. Given the recognition of such losses above and beyond the impact of forecasted losses used in determining the fair value of the loans acquired at a premium, the initial $21 million provision for credit losses has been noted as a merger-related expense. A summary of merger-related expenses included in the consolidated statement of income for the years ended December 31, 2016 and 2015 follows: 2016 2015 (In thousands) Salaries and employee benefits $ 5,334 $ 51,287 Equipment and net occupancy 1,278 3 Outside data processing and software 1,067 785 Advertising and marketing 10,522 79 Printing, postage and supplies 1,482 504 Other cost of operations 16,072 23,318 Other expense 35,755 75,976 Provision for credit losses — 21,000 Total $ 35,755 $ 96,976 Sale of trust accounts In April 2015, the Company sold the trade processing business within the retirement services division of its Institutional Client Services business. That sale resulted in an after-tax gain of $23 million ($45 million pre-tax) that reflected the allocation of approximately $11 million of previously recorded goodwill to the divested business. Revenues of the sold business had been included in “trust income” and were $9 million and $34 million during 2015 and 2014, respectively. After considering related expenses, net income attributable to the business that was sold was not material to the consolidated results of operations of the Company in any of those periods.

Investment securities

Investment securities	12 Months Ended
	Dec. 31, 2016
Investments Debt And Equity Securities [Abstract]
Investment securities	3. Investment securities The amortized cost and estimated fair value of investment securities were as follows: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value (In thousands) December 31, 2016 Investment securities available for sale: U.S. Treasury and federal agencies $ 1,912,110 $ 386 $ 9,952 $ 1,902,544 Obligations of states and political subdivisions 3,570 77 6 3,641 Mortgage-backed securities: Government issued or guaranteed 10,980,507 88,343 113,989 10,954,861 Privately issued 45 — 1 44 Other debt securities 134,105 1,407 16,996 118,516 Equity securities 307,964 45,073 571 352,466 13,338,301 135,286 141,515 13,332,072 Investment securities held to maturity: Obligations of states and political subdivisions 60,858 267 224 60,901 Mortgage-backed securities: Government issued or guaranteed 2,233,173 37,498 7,374 2,263,297 Privately issued 157,704 897 37,120 121,481 Other debt securities 5,543 — — 5,543 2,457,278 38,662 44,718 2,451,222 Other securities 461,118 — — 461,118 Total $ 16,256,697 $ 173,948 $ 186,233 $ 16,244,412 December 31, 2015 Investment securities available for sale: U.S. Treasury and federal agencies $ 299,890 $ 294 $ 187 $ 299,997 Obligations of states and political subdivisions 5,924 146 42 6,028 Mortgage-backed securities: Government issued or guaranteed 11,592,959 142,370 48,701 11,686,628 Privately issued 74 2 2 74 Collateralized debt obligations 28,438 20,143 1,188 47,393 Other debt securities 137,556 1,514 20,190 118,880 Equity securities 73,795 10,230 354 83,671 12,138,636 174,699 70,664 12,242,671 Investment securities held to maturity: Obligations of states and political subdivisions 118,431 1,003 421 119,013 Mortgage-backed securities: Government issued or guaranteed 2,553,612 50,936 7,817 2,596,731 Privately issued 181,091 2,104 41,367 141,828 Other debt securities 6,575 — — 6,575 2,859,709 54,043 49,605 2,864,147 Other securities 554,059 — — 554,059 Total $ 15,552,404 $ 228,742 $ 120,269 $ 15,660,877 No investment in securities of a single non-U.S. Government, government agency or government guaranteed issuer exceeded ten percent of shareholders’ equity at December 31, 2016. As of December 31, 2016, the latest available investment ratings of all obligations of states and political subdivisions, privately issued mortgage-backed securities and other debt securities were: Average Credit Rating of Fair Value Amount Amortized Cost Estimated Fair Value A or Better BBB BB B or Less Not Rated (In thousands) Obligations of states and political subdivisions $ 64,428 $ 64,542 $ 47,023 $ — $ — $ — $ 17,519 Privately issued mortgage-backed securities 157,749 121,525 30,760 16 — 90,730 19 Other debt securities 139,648 124,059 5,442 63,353 30,373 — 24,891 Total $ 361,825 $ 310,126 $ 83,225 $ 63,369 $ 30,373 $ 90,730 $ 42,429 The amortized cost and estimated fair value of collateralized mortgage obligations included in mortgage-backed securities were as follows: December 31 2016 2015 (In thousands) Collateralized mortgage obligations: Amortized cost $ 162,027 $ 188,819 Estimated fair value 125,848 149,632 Gross realized gains from sales of investment securities were $30,545,000 in 2016. During 2016, the Company sold its collateralized debt obligations held in the available-for-sale investment securities portfolio for a gain of $30 million. There were no significant realized gross losses from sales of investments securities in 2016. There were no significant gross realized gains or losses from sales of investment securities in 2015 or 2014. At December 31, 2016, the amortized cost and estimated fair value of debt securities by contractual maturity were as follows: Amortized Cost Estimated Fair Value (In thousands) Debt securities available for sale: Due in one year or less $ 157,954 $ 158,334 Due after one year through five years 1,760,301 1,750,542 Due after five years through ten years 2,689 3,132 Due after ten years 128,841 112,693 2,049,785 2,024,701 Mortgage-backed securities available for sale 10,980,552 10,954,905 $ 13,030,337 $ 12,979,606 Debt securities held to maturity: Due in one year or less $ 24,533 $ 24,643 Due after one year through five years 34,073 33,963 Due after five years through ten years 2,252 2,295 Due after ten years 5,543 5,543 66,401 66,444 Mortgage-backed securities held to maturity 2,390,877 2,384,778 $ 2,457,278 $ 2,451,222 A summary of investment securities that as of December 31, 2016 and 2015 had been in a continuous unrealized loss position for less than twelve months and those that had been in a continuous unrealized loss position for twelve months or longer follows: Less Than 12 Months 12 Months or More Fair Value Unrealized Losses Fair Value Unrealized Losses (In thousands) December 31, 2016 Investment securities available for sale: U.S. Treasury and federal agencies $ 1,710,241 $ (9,950 ) $ 2,295 $ (2 ) Obligations of states and political subdivisions — — 593 (6 ) Mortgage-backed securities: Government issued or guaranteed 6,730,829 (113,374 ) 81,003 (615 ) Privately issued — — 27 (1 ) Other debt securities 100 (1 ) 85,400 (16,995 ) Equity securities 17,776 (422 ) 151 (149 ) 8,458,946 (123,747 ) 169,469 (17,768 ) Investment securities held to maturity: Obligations of states and political subdivisions 17,988 (126 ) 11,891 (98 ) Mortgage-backed securities: Government issued or guaranteed 618,832 (6,842 ) 17,481 (532 ) Privately issued 17,911 (1,222 ) 57,016 (35,898 ) 654,731 (8,190 ) 86,388 (36,528 ) Total $ 9,113,677 $ (131,937 ) $ 255,857 $ (54,296 ) December 31, 2015 Investment securities available for sale: U.S. Treasury and federal agencies $ 147,508 $ (187 ) $ — $ — Obligations of states and political subdivisions 865 (2 ) 1,335 (40 ) Mortgage-backed securities: Government issued or guaranteed 4,061,899 (48,534 ) 7,216 (167 ) Privately issued — — 43 (2 ) Collateralized debt obligations 5,711 (335 ) 2,063 (853 ) Other debt securities 12,935 (462 ) 93,344 (19,728 ) Equity securities 18,073 (207 ) 153 (147 ) 4,246,991 (49,727 ) 104,154 (20,937 ) Investment securities held to maturity: Obligations of states and political subdivisions 42,913 (335 ) 5,853 (86 ) Mortgage-backed securities: Government issued or guaranteed 459,983 (1,801 ) 228,867 (6,016 ) Privately issued — — 112,155 (41,367 ) 502,896 (2,136 ) 346,875 (47,469 ) Total $ 4,749,887 $ (51,863 ) $ 451,029 $ (68,406 ) The Company owned 1,083 individual investment securities with aggregate gross unrealized losses of $186 million at December 31, 2016. Based on a review of each of the securities in the investment securities portfolio at December 31, 2016, the Company concluded that it expected to recover the amortized cost basis of its investment. As of December 31, 2016, the Company does not intend to sell nor is it anticipated that it would be required to sell any of its impaired investment securities at a loss. At December 31, 2016, the Company has not identified events or changes in circumstances which may have a significant adverse effect on the fair value of the $461 million of cost method investment securities. At December 31, 2016, investment securities with a carrying value of $3,775,571,000, including $3,240,079,000 of investment securities available for sale, were pledged to secure borrowings from various FHLBs, repurchase agreements, governmental deposits, interest rate swap agreements and available lines of credit as described in note 9. Investment securities pledged by the Company to secure obligations whereby the secured party is permitted by contract or custom to sell or repledge such collateral totaled $1,203,473,000 at December 31, 2016. The pledged securities included securities of the U.S. Treasury and federal agencies and mortgage-backed securities.

Loans and leases

Loans and leases	12 Months Ended
	Dec. 31, 2016
Receivables [Abstract]
Loans and leases	4. Loans and leases Total loans and leases outstanding were comprised of the following: December 31 2016 2015 (In thousands) Loans Commercial, financial, etc. $ 21,351,119 $ 19,223,419 Real estate: Residential 22,584,141 26,249,059 Commercial 25,550,057 23,592,097 Construction 8,066,756 5,716,994 Consumer 12,130,094 11,584,347 Total loans 89,682,167 86,365,916 Leases Commercial 1,419,510 1,353,318 Total loans and leases 91,101,677 87,719,234 Less: unearned discount (248,261 ) (229,735 ) Total loans and leases, net of unearned discount $ 90,853,416 $ 87,489,499 One-to-four family residential mortgage loans held for sale were $414 million at December 31, 2016 and $353 million at December 31, 2015. Commercial real estate loans held for sale were $643 million at December 31, 2016 and $39 million at December 31, 2015. As of December 31, 2016, approximately $2.8 billion of commercial real estate loan balances serviced for others had been sold with recourse in conjunction with the Company’s participation in the Federal National Mortgage Association (“Fannie Mae”) Delegated Underwriting and Servicing (“DUS”) program. At December 31, 2016, the Company estimated that the recourse obligations described above were not material to the Company’s consolidated financial position. There have been no material losses incurred as a result of those credit recourse arrangements. In addition to recourse obligations, as described in note 21, the Company is contractually obligated to repurchase previously sold residential real estate loans that do not ultimately meet investor sale criteria related to underwriting procedures or loan documentation. When required to do so, the Company may reimburse loan purchasers for losses incurred or may repurchase certain loans. Charges incurred for such obligation, which are recorded as a reduction of mortgage banking revenues, were $4 million, $5 million and $4 million in 2016, 2015 and 2014, respectively. The outstanding principal balance and the carrying amount of loans acquired at a discount that were recorded at fair value at the acquisition date and included in the consolidated balance sheet were as follows: December 31 2016 2015 (In thousands) Outstanding principal balance $ 2,311,699 $ 3,122,935 Carrying amount: Commercial, financial, leasing, etc. 59,928 78,847 Commercial real estate 456,820 644,284 Residential real estate 799,802 1,016,129 Consumer 487,721 725,807 $ 1,804,271 $ 2,465,067 Purchased impaired loans included in the table above totaled $578 million at December 31, 2016 and $768 million at December 31, 2015, representing less than 1% of the Company’s assets as of each date. A summary of changes in the accretable yield for loans acquired at a discount for the years ended December 31, 2016, 2015 and 2014 follows: For the Year Ended December 31, 2016 2015 2014 Purchased Other Purchased Other Purchased Other Impaired Acquired Impaired Acquired Impaired Acquired (In thousands) Balance at beginning of period $ 184,618 $ 296,434 $ 76,518 $ 397,379 $ 37,230 $ 538,633 Additions — — 117,251 — — — Interest income (52,769 ) (123,044 ) (28,551 ) (158,260 ) (21,263 ) (178,670 ) Reclassifications from nonaccretable balance 22,384 22,677 19,400 49,930 60,551 24,907 Other(a) — 5,086 — 7,385 — 12,509 Balance at end of period $ 154,233 $ 201,153 $ 184,618 $ 296,434 $ 76,518 $ 397,379 (a) Other changes in expected cash flows including changes in interest rates and prepayment assumptions. A summary of current, past due and nonaccrual loans as of December 31, 2016 and 2015 follows: Current 30-89 Days Past Due Accruing Loans Past Due 90 Days or More(a) Accruing Loans Acquired at a Discount Past Due 90 Days or More(b) Purchased Impaired(c) Nonaccrual Total (In thousands) December 31, 2016 Commercial, financial, leasing, etc. $ 22,287,857 $ 53,503 $ 6,195 $ 417 $ 641 $ 261,434 $ 22,610,047 Real estate: Commercial 25,076,684 183,531 7,054 12,870 31,404 176,201 25,487,744 Residential builder and developer 1,884,989 4,667 5 1,952 14,006 16,707 1,922,326 Other commercial construction 5,985,118 77,701 922 198 14,274 18,111 6,096,324 Residential 17,631,377 485,468 281,298 11,537 378,549 229,242 19,017,471 Residential — limited documentation 3,239,344 88,366 — — 139,158 106,573 3,573,441 Consumer: Home equity lines and loans 5,502,091 44,565 — 12,678 — 81,815 5,641,149 Automobile 2,869,232 56,158 — 1 — 18,674 2,944,065 Other 3,491,629 31,286 5,185 21,491 — 11,258 3,560,849 Total $ 87,968,321 $ 1,025,245 $ 300,659 $ 61,144 $ 578,032 $ 920,015 $ 90,853,416 December 31, 2015 Commercial, financial, leasing, etc. $ 20,122,648 $ 52,868 $ 2,310 $ 693 $ 1,902 $ 241,917 $ 20,422,338 Real estate: Commercial(d) 23,111,673 172,439 12,963 8,790 46,790 179,606 23,532,261 Residential builder and developer 1,507,856 7,969 5,760 6,925 28,734 28,429 1,585,673 Other commercial construction(d) 3,962,620 65,932 7,936 2,001 24,525 16,363 4,079,377 Residential 20,507,551 560,312 284,451 16,079 488,599 153,281 22,010,273 Residential — limited documentation 3,885,073 137,289 — — 175,518 61,950 4,259,830 Consumer: Home equity lines and loans 5,805,222 45,604 — 15,222 2,261 84,467 5,952,776 Automobile 2,446,473 56,181 — 6 — 16,597 2,519,257 Other 3,051,435 36,702 4,021 18,757 — 16,799 3,127,714 Total $ 84,400,551 $ 1,135,296 $ 317,441 $ 68,473 $ 768,329 $ 799,409 $ 87,489,499 (a) Excludes loans acquired at a discount. (b) Loans acquired at a discount that were recorded at fair value at acquisition date. This category does not include purchased impaired loans that are presented separately. (c) Accruing loans acquired at a discount that were impaired at acquisition date and recorded at fair value. (d) The Company expanded its definition of construction loans in 2016 and, as a result, re-characterized certain commercial real estate loans as other commercial construction loans. The December 31, 2015 balances reflect such changes. If nonaccrual and renegotiated loans had been accruing interest at their originally contracted terms, interest income on such loans would have amounted to $68,371,000 in 2016, $56,784,000 in 2015 and $58,314,000 in 2014. The actual amounts included in interest income during 2016, 2015 and 2014 on such loans were $33,941,000, $30,735,000 and $28,492,000, respectively. During the normal course of business, the Company modifies loans to maximize recovery efforts. If the borrower is experiencing financial difficulty and a concession is granted, the Company considers such modifications as troubled debt restructurings and classifies those loans as either nonaccrual loans or renegotiated loans. The types of concessions that the Company grants typically include principal deferrals and interest rate concessions, but may also include other types of concessions. The table below summarizes the Company’s loan modification activities that were considered troubled debt restructurings for the year ended December 31, 2016: Recorded Investment Financial Effects of Modification Number Pre- modification Post- modification Recorded Investment(a) Interest (b) (Dollars in thousands) Commercial, financial, leasing, etc. Principal deferral 127 $ 102,872 $ 102,446 $ (426 ) $ — Combination of concession types 37 51,221 41,673 (9,548 ) (95 ) Real estate: Commercial Principal deferral 56 24,323 23,558 (765 ) — Interest rate reduction 1 129 129 — (25 ) Other 1 4,723 4,447 (276 ) — Combination of concession types 23 15,695 15,603 (92 ) (585 ) Residential builder and developer Principal deferral 3 23,905 22,958 (947 ) — Combination of concession types 3 15,755 15,123 (632 ) — Other commercial construction Principal deferral 1 250 250 — — Combination of concession types 2 2,863 2,782 (81 ) — Residential Principal deferral 73 11,082 11,771 689 — Combination of concession types 46 8,975 9,367 392 (120 ) Residential-limited documentation Principal deferral 8 902 1,047 145 — Combination of concession types 13 2,658 2,917 259 (706 ) Consumer: Home equity lines and loans Principal deferral 10 760 761 1 — Combination of concession types 93 11,110 11,110 — (916 ) Automobile Principal deferral 117 1,124 1,124 — — Other 38 55 55 — — Combination of concession types 8 85 85 — (3 ) Other Principal deferral 57 968 968 — — Other 5 45 45 — — Combination of concession types 17 196 196 — (32 ) Total 739 $ 279,696 $ 268,415 $ (11,281 ) $ (2,482 ) (a) Financial effects impacting the recorded investment included principal payments or advances, charge-offs and capitalized escrow arrearages. (b) Represents the present value of interest rate concessions discounted at the effective rate of the original loan. The table below summarizes the Company’s loan modification activities that were considered troubled debt restructurings for the year ended December 31, 2015: Recorded Investment Financial Effects of Modification Number Pre- modification Post- modification Recorded Investment(a) Interest (b) (Dollars in thousands) Commercial, financial, leasing, etc. Principal deferral 114 $ 55,621 $ 50,807 $ (4,814 ) $ — Interest rate reduction 1 99 99 — (19 ) Other 3 12,965 12,827 (138 ) — Combination of concession types 9 32,444 31,439 (1,005 ) (245 ) Real estate: Commercial Principal deferral 49 49,486 48,388 (1,098 ) — Other 3 4,169 4,087 (82 ) — Combination of concession types 6 3,238 3,242 4 (159 ) Residential builder and developer Principal deferral 2 10,650 10,598 (52 ) — Other commercial construction Principal deferral 4 368 460 92 — Combination of concession types 2 10,375 10,375 — (49 ) Residential Principal deferral 58 6,194 6,528 334 — Other 1 267 267 — — Combination of concession types 26 4,024 4,277 253 (483 ) Residential-limited documentation Principal deferral 2 426 437 11 — Combination of concession types 9 1,536 1,635 99 (121 ) Consumer: Home equity lines and loans Principal deferral 8 2,175 2,175 — — Combination of concession types 63 5,203 5,204 1 (677 ) Automobile Principal deferral 192 1,818 1,818 — — Interest rate reduction 7 137 137 — (10 ) Other 46 150 150 — — Combination of concession types 57 948 948 — (43 ) Other Principal deferral 102 1,995 1,995 — — Other 13 116 116 — — Combination of concession types 40 396 396 — (45 ) Total 817 $ 204,800 $ 198,405 $ (6,395 ) $ (1,851 ) (a) Financial effects impacting the recorded investment included principal payments or advances, charge-offs and capitalized escrow arrearages. (b) Represents the present value of interest rate concessions discounted at the effective rate of the original loan. The table below summarizes the Company’s loan modification activities that were considered troubled debt restructurings for the year ended December 31, 2014: Recorded Investment Financial Effects of Modification Number Pre- modification Post- modification Recorded Investment(a) Interest (b) (Dollars in thousands) Commercial, financial, leasing, etc. Principal deferral 95 $ 29,035 $ 23,628 $ (5,407 ) $ — Other 3 29,912 31,604 1,692 — Combination of concession types 7 19,167 19,030 (137 ) (20 ) Real estate: Commercial Principal deferral 39 19,077 18,997 (80 ) — Interest rate reduction 1 255 252 (3 ) (48 ) Other 1 650 — (650 ) — Combination of concession types 7 1,152 1,198 46 (264 ) Residential builder and developer Principal deferral 2 1,639 1,639 — — Other commercial construction Principal deferral 4 6,703 6,611 (92 ) — Residential Principal deferral 28 2,710 2,905 195 — Interest rate reduction 11 1,146 1,222 76 (152 ) Other 1 188 188 — — Combination of concession types 30 4,211 4,287 76 (483 ) Residential-limited documentation Principal deferral 6 880 963 83 — Combination of concession types 21 3,806 3,846 40 (386 ) Consumer: Home equity lines and loans Principal deferral 3 280 280 — — Interest rate reduction 6 535 535 — (120 ) Combination of concession types 47 5,031 5,031 — (560 ) Automobile Principal deferral 208 3,293 3,293 — — Interest rate reduction 9 152 152 — (12 ) Other 42 255 255 — — Combination of concession types 81 1,189 1,189 — (100 ) Other Principal deferral 33 245 245 — — Interest rate reduction 4 293 293 — (63 ) Other 1 45 45 — — Combination of concession types 70 2,502 2,502 — (761 ) Total 760 $ 134,351 $ 130,190 $ (4,161 ) $ (2,969 ) (a) Financial effects impacting the recorded investment included principal payments or advances, charge-offs and capitalized escrow arrearages. (b) Represents the present value of interest rate concessions discounted at the effective rate of the original loan. Troubled debt restructurings are considered to be impaired loans and for purposes of establishing the allowance for credit losses are evaluated for impairment giving consideration to the impact of the modified loan terms on the present value of the loan’s expected cash flows. Impairment of troubled debt restructurings that have subsequently defaulted may also be measured based on the loan’s observable market price or the fair value of collateral if the loan is collateral-dependent. Charge-offs may also be recognized on troubled debt restructurings that have subsequently defaulted. Loans that were modified as troubled debt restructurings during the twelve months ended December 31, 2016, 2015 and 2014 and for which there was a subsequent payment default during the respective period were not material. Borrowings by directors and certain officers of M&T and its banking subsidiaries, and by associates of such persons, exclusive of loans aggregating less than $120,000, amounted to $63,543,000 and $52,152,000 at December 31, 2016 and 2015, respectively. During 2016, new borrowings by such persons amounted to $15,350,000 (including any borrowings of new directors or officers that were outstanding at the time of their election) and repayments and other reductions (including reductions resulting from retirements) were $3,959,000. At December 31, 2016, approximately $11.9 billion of commercial loans and leases, $12.5 billion of commercial real estate loans, $17.8 billion of one-to-four family residential real estate loans, $2.3 billion of home equity loans and lines of credit and $4.4 billion of other consumer loans were pledged to secure outstanding borrowings from the FHLB of New York and available lines of credit as described in note 9. The Company’s loan and lease portfolio includes commercial lease financing receivables consisting of direct financing and leveraged leases for machinery and equipment, railroad equipment, commercial trucks and trailers, and aircraft. A summary of lease financing receivables follows: December 31 2016 2015 (In thousands) Commercial leases: Direct financings: Lease payments receivable $ 1,136,815 $ 1,058,605 Estimated residual value of leased assets 79,449 81,269 Unearned income (107,535 ) (102,723 ) Investment in direct financings 1,108,729 1,037,151 Leveraged leases: Lease payments receivable 92,918 95,316 Estimated residual value of leased assets 110,328 118,128 Unearned income (38,760 ) (41,556 ) Investment in leveraged leases 164,486 171,888 Total investment in leases $ 1,273,215 $ 1,209,039 Deferred taxes payable arising from leveraged leases $ 139,067 $ 160,603 Included within the estimated residual value of leased assets at December 31, 2016 and 2015 were $47 million and $50 million, respectively, in residual value associated with direct financing leases that are guaranteed by the lessees or others. At December 31, 2016, the minimum future lease payments to be received from lease financings were as follows: (In thousands) Year ending December 31: 2017 $ 301,611 2018 276,524 2019 209,835 2020 150,631 2021 101,403 Later years 189,729 $ 1,229,733 The amount of foreclosed residential real estate property held by the Company was $129 million and $172 million at December 31, 2016 and 2015, respectively. There were $314 million and $315 million at December 31, 2016 and 2015, respectively, in loans secured by residential real estate and serviced by the Company that were in the process of foreclosure. There were $192 million in loans secured by residential real estate and serviced by other entities for the Company that were in the process of foreclosure at December 31, 2016. Of all the loans in the process of foreclosure at December 31, 2016, approximately 57% were classified as purchased impaired and 20% were government guaranteed.

Allowance for credit losses

Allowance for credit losses	12 Months Ended
	Dec. 31, 2016
Receivables [Abstract]
Allowance for credit losses	5. Allowance for credit losses Changes in the allowance for credit losses for the years ended December 31, 2016, 2015 and 2014 were as follows: Commercial, Financial, Real Estate 2016 Leasing, etc. Commercial Residential Consumer Unallocated Total (In thousands) Beginning balance $ 300,404 326,831 72,238 178,320 78,199 $ 955,992 Provision for credit losses 59,506 33,627 6,902 90,134 (169 ) 190,000 Net charge-offs Charge-offs (59,244 ) (4,805 ) (26,133 ) (141,073 ) — (231,255 ) Recoveries 30,167 7,066 8,120 28,907 — 74,260 Net (charge-offs) recoveries (29,077 ) 2,261 (18,013 ) (112,166 ) — (156,995 ) Ending balance $ 330,833 362,719 61,127 156,288 78,030 $ 988,997 Commercial, Financial, Real Estate 2015 Leasing, etc. Commercial Residential Consumer Unallocated Total (In thousands) Beginning balance $ 288,038 307,927 61,910 186,033 75,654 $ 919,562 Provision for credit losses 43,065 25,768 19,133 79,489 2,545 170,000 Net charge-offs Charge-offs (60,983 ) (16,487 ) (13,116 ) (107,787 ) — (198,373 ) Recoveries 30,284 9,623 4,311 20,585 — 64,803 Net charge-offs (30,699 ) (6,864 ) (8,805 ) (87,202 ) — (133,570 ) Ending balance $ 300,404 326,831 72,238 178,320 78,199 $ 955,992 2014 Beginning balance $ 273,383 324,978 78,656 164,644 75,015 $ 916,676 Provision for credit losses 51,410 (13,779 ) (3,974 ) 89,704 639 124,000 Net charge-offs Charge-offs (58,943 ) (14,058 ) (21,351 ) (84,390 ) — (178,742 ) Recoveries 22,188 10,786 8,579 16,075 — 57,628 Net charge-offs (36,755 ) (3,272 ) (12,772 ) (68,315 ) — (121,114 ) Ending balance $ 288,038 307,927 61,910 186,033 75,654 $ 919,562 Despite the above allocation, the allowance for credit losses is general in nature and is available to absorb losses from any loan or lease type. In establishing the allowance for credit losses, the Company estimates losses attributable to specific troubled credits identified through both normal and detailed or intensified credit review processes and also estimates losses inherent in other loans and leases on a collective basis. For purposes of determining the level of the allowance for credit losses, the Company evaluates its loan and lease portfolio by loan type. The amounts of loss components in the Company’s loan and lease portfolios are determined through a loan-by-loan analysis of larger balance commercial loans and commercial real estate loans that are in nonaccrual status and by applying loss factors to groups of loan balances based on loan type and management’s classification of such loans under the Company’s loan grading system. Measurement of the specific loss components is typically based on expected future cash flows, collateral values and other factors that may impact the borrower’s ability to pay. In determining the allowance for credit losses, the Company utilizes a loan grading system which is applied to commercial and commercial real estate credits on an individual loan basis. Loan officers are responsible for continually assigning grades to these loans based on standards outlined in the Company’s Credit Policy. Internal loan grades are also monitored by the Company’s credit review department to ensure consistency and strict adherence to the prescribed standards. Loan grades are assigned loss component factors that reflect the Company’s loss estimate for each group of loans and leases. Factors considered in assigning loan grades and loss component factors include borrower-specific information related to expected future cash flows and operating results, collateral values, geographic location, financial condition and performance, payment status, and other information; levels of and trends in portfolio charge-offs and recoveries; levels of and trends in portfolio delinquencies and impaired loans; changes in the risk profile of specific portfolios; trends in volume and terms of loans; effects of changes in credit concentrations; and observed trends and practices in the banking industry. As updated appraisals are obtained on individual loans or other events in the market place indicate that collateral values have significantly changed, individual loan grades are adjusted as appropriate. Changes in other factors cited may also lead to loan grade changes at any time. Except for consumer loans and residential real estate loans that are considered smaller balance homogenous loans and acquired loans that are evaluated on an aggregated basis, the Company considers a loan to be impaired for purposes of applying GAAP when, based on current information and events, it is probable that the Company will be unable to collect all amounts according to the contractual terms of the loan agreement or the loan is delinquent 90 days. Regardless of loan type, the Company considers a loan to be impaired if it qualifies as a troubled debt restructuring. Modified loans, including smaller balance homogenous loans, that are considered to be troubled debt restructurings are evaluated for impairment giving consideration to the impact of the modified loan terms on the present value of the loan’s expected cash flows. The following tables provide information with respect to loans and leases that were considered impaired as of December 31, 2016 and 2015 and for the years ended December 31, 2016, 2015 and 2014. December 31, 2016 December 31, 2015 Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance Related Allowance (In thousands) With an allowance recorded: Commercial, financial, leasing, etc. $ 168,072 184,432 48,480 179,037 195,821 44,752 Real estate: Commercial 71,862 86,666 11,620 85,974 95,855 18,764 Residential builder and developer 7,396 8,361 506 3,316 5,101 196 Other commercial construction 2,475 2,731 448 3,548 3,843 348 Residential 86,680 105,944 3,457 79,558 96,751 4,727 Residential-limited documentation 82,547 97,718 6,000 90,356 104,251 8,000 Consumer: Home equity lines and loans 44,693 48,965 8,027 25,220 26,195 3,777 Automobile 16,982 18,272 3,740 22,525 22,525 4,709 Other 3,791 5,296 776 17,620 17,620 4,820 484,498 558,385 83,054 507,154 567,962 90,093 With no related allowance recorded: Commercial, financial, leasing, etc. 100,805 124,786 — 93,190 110,735 — Real estate: Commercial 113,276 121,846 — 101,340 116,230 — Residential builder and developer 14,368 21,124 — 27,651 47,246 — Other commercial construction 15,933 35,281 — 13,221 31,477 — Residential 16,823 24,161 — 19,621 30,940 — Residential-limited documentation 15,429 24,590 — 18,414 31,113 — 276,634 351,788 — 273,437 367,741 — Total: Commercial, financial, leasing, etc. 268,877 309,218 48,480 272,227 306,556 44,752 Real estate: Commercial 185,138 208,512 11,620 187,314 212,085 18,764 Residential builder and developer 21,764 29,485 506 30,967 52,347 196 Other commercial construction 18,408 38,012 448 16,769 35,320 348 Residential 103,503 130,105 3,457 99,179 127,691 4,727 Residential-limited documentation 97,976 122,308 6,000 108,770 135,364 8,000 Consumer: Home equity lines and loans 44,693 48,965 8,027 25,220 26,195 3,777 Automobile 16,982 18,272 3,740 22,525 22,525 4,709 Other 3,791 5,296 776 17,620 17,620 4,820 Total $ 761,132 910,173 83,054 780,591 935,703 90,093 Year Ended December 31, 2016 Year Ended December 31, 2015 Interest Income Recognized Interest Income Recognized Average Recorded Investment Total Cash Basis Average Recorded Investment Total Cash Basis (In thousands) Commercial, financial, leasing, etc. $ 277,647 8,342 8,342 236,201 2,933 2,933 Real estate: Commercial 175,877 4,878 4,878 166,628 6,243 6,243 Residential builder and developer 29,237 2,300 2,300 59,457 335 335 Other commercial construction 19,697 644 644 20,276 2,311 2,311 Residential 98,394 6,227 3,154 101,483 6,188 4,037 Residential-limited documentation 103,060 5,999 1,975 118,449 6,380 2,638 Consumer: Home equity lines and loans 36,493 1,325 410 21,523 905 261 Automobile 19,636 1,242 99 25,675 1,619 175 Other 9,218 440 83 18,809 729 113 Total $ 769,259 31,397 21,885 768,501 27,643 19,046 Year Ended December 31, 2014 Interest Income Recognized Average Recorded Investment Total Cash Basis (In thousands) Commercial, financial, leasing, etc. $ 181,932 2,251 2,251 Real estate: Commercial 184,773 4,029 4,029 Residential builder and developer 91,149 142 142 Other commercial construction 62,734 1,893 1,893 Residential 126,005 9,180 6,978 Residential-limited documentation 133,800 6,613 2,546 Consumer: Home equity lines and loans 18,083 750 248 Automobile 35,173 2,251 295 Other 18,378 690 191 Total $ 852,027 27,799 18,573 In accordance with the previously described policies, the Company utilizes a loan grading system that is applied to all commercial loans and commercial real estate loans. Loan grades are utilized to differentiate risk within the portfolio and consider the expectations of default for each loan. Commercial loans and commercial real estate loans with a lower expectation of default are assigned one of ten possible “pass” loan grades and are generally ascribed lower loss factors when determining the allowance for credit losses. Loans with an elevated level of credit risk are classified as “criticized” and are ascribed a higher loss factor when determining the allowance for credit losses. Criticized loans may be classified as “nonaccrual” if the Company no longer expects to collect all amounts according to the contractual terms of the loan agreement or the loan is delinquent 90 days or more. All larger-balance criticized commercial loans and commercial real estate loans are individually reviewed by centralized credit personnel each quarter to determine the appropriateness of the assigned loan grade, including whether the loan should be reported as accruing or nonaccruing. Smaller-balance criticized loans are analyzed by business line risk management areas to ensure proper loan grade classification. Furthermore, criticized nonaccrual commercial loans and commercial real estate loans are considered impaired and, as a result, specific loss allowances on such loans are established within the allowance for credit losses to the extent appropriate in each individual instance. The following table summarizes the loan grades applied to the various classes of the Company’s commercial loans and commercial real estate loans. Real Estate Commercial, Residential Other Financial, Builder and Commercial Leasing, etc. Commercial Developer Construction (In thousands) December 31, 2016 Pass $ 21,398,581 24,570,269 1,789,071 5,912,351 Criticized accrual 950,032 741,274 116,548 165,862 Criticized nonaccrual 261,434 176,201 16,707 18,111 Total $ 22,610,047 25,487,744 1,922,326 6,096,324 December 31, 2015 Pass $ 19,442,183 22,697,398 1,497,465 3,834,137 Criticized accrual 738,238 655,257 59,779 228,877 Criticized nonaccrual 241,917 179,606 28,429 16,363 Total $ 20,422,338 23,532,261 1,585,673 4,079,377 In determining the allowance for credit losses, residential real estate loans and consumer loans are generally evaluated collectively after considering such factors as payment performance and recent loss experience and trends, which are mainly driven by current collateral values in the market place as well as the amount of loan defaults. Loss rates on such loans are determined by reference to recent charge-off history and are evaluated (and adjusted if deemed appropriate) through consideration of other factors including near-term forecasted loss estimates developed by the Company’s credit department. In arriving at such forecasts, the Company considers the current estimated fair value of its collateral based on geographical adjustments for home price depreciation/appreciation and overall borrower repayment performance. With regard to collateral values, the realizability of such values by the Company contemplates repayment of any first lien position prior to recovering amounts on a second lien position. However, residential real estate loans and outstanding balances of home equity loans and lines of credit that are more than 150 days past due are generally evaluated for collectibility on a loan-by-loan basis giving consideration to estimated collateral values. The carrying value of residential real estate loans and home equity loans and lines of credit for which a partial charge-off has been recognized aggregated $44 million and $32 million, respectively, at December 31, 2016 and $55 million and $21 million, respectively, at December 31, 2015. Residential real estate loans and home equity loans and lines of credit that were more than 150 days past due but did not require a partial charge-off because the net realizable value of the collateral exceeded the outstanding customer balance totaled $16 million and $39 million, respectively, at December 31, 2016 and $20 million and $28 million, respectively, at December 31, 2015. The Company also measures additional losses for purchased impaired loans when it is probable that the Company will be unable to collect all cash flows expected at acquisition plus additional cash flows expected to be collected arising from changes in estimates after acquisition. The determination of the allocated portion of the allowance for credit losses is very subjective. Given that inherent subjectivity and potential imprecision involved in determining the allocated portion of the allowance for credit losses, the Company also provides an inherent unallocated portion of the allowance. The unallocated portion of the allowance is intended to recognize probable losses that are not otherwise identifiable and includes management’s subjective determination of amounts necessary to provide for the possible use of imprecise estimates in determining the allocated portion of the allowance. Therefore, the level of the unallocated portion of the allowance is primarily reflective of the inherent imprecision in the various calculations used in determining the allocated portion of the allowance for credit losses. Other factors that could also lead to changes in the unallocated portion include the effects of expansion into new markets for which the Company does not have the same degree of familiarity and experience regarding portfolio performance in changing market conditions, the introduction of new loan and lease product types, and other risks associated with the Company’s loan portfolio that may not be specifically identifiable. The allocation of the allowance for credit losses summarized on the basis of the Company’s impairment methodology was as follows: Commercial, Financial, Real Estate Leasing, etc. Commercial Residential Consumer Total (In thousands) December 31, 2016 Individually evaluated for impairment $ 48,480 12,500 9,457 12,543 $ 82,980 Collectively evaluated for impairment 282,353 348,301 47,993 143,745 822,392 Purchased impaired — 1,918 3,677 — 5,595 Allocated $ 330,833 362,719 61,127 156,288 910,967 Unallocated 78,030 Total $ 988,997 December 31, 2015 Individually evaluated for impairment $ 44,752 19,175 12,727 13,306 $ 89,960 Collectively evaluated for impairment 255,615 307,000 57,624 163,511 783,750 Purchased impaired 37 656 1,887 1,503 4,083 Allocated $ 300,404 326,831 72,238 178,320 877,793 Unallocated 78,199 Total $ 955,992 The recorded investment in loans and leases summarized on the basis of the Company’s impairment methodology was as follows: Commercial, Financial, Real Estate Leasing, etc. Commercial Residential Consumer Total (In thousands) December 31, 2016 Individually evaluated for impairment $ 268,877 224,630 201,479 65,466 $ 760,452 Collectively evaluated for impairment 22,340,529 33,222,080 21,871,726 12,080,597 89,514,932 Purchased impaired 641 59,684 517,707 — 578,032 Total $ 22,610,047 33,506,394 22,590,912 12,146,063 $ 90,853,416 December 31, 2015 Individually evaluated for impairment $ 272,227 234,132 207,949 65,365 $ 779,673 Collectively evaluated for impairment 20,148,209 28,863,130 25,398,037 11,532,121 85,941,497 Purchased impaired 1,902 100,049 664,117 2,261 768,329 Total $ 20,422,338 29,197,311 26,270,103 11,599,747 $ 87,489,499

Premises and equipment

Premises and equipment	12 Months Ended
	Dec. 31, 2016
Property Plant And Equipment [Abstract]
Premises and equipment	6. Premises and equipment The detail of premises and equipment was as follows: December 31 2016 2015 (In thousands) Land $ 104,671 $ 105,435 Buildings — owned 448,442 443,507 Buildings — capital leases — 1,108 Leasehold improvements 232,936 229,919 Furniture and equipment — owned 636,219 614,591 Furniture and equipment — capital leases 14,849 12,019 1,437,117 1,406,579 Less: accumulated depreciation and amortization Owned assets 756,245 732,315 Capital leases 5,609 7,582 761,854 739,897 Premises and equipment, net $ 675,263 $ 666,682 Net lease expense for all operating leases totaled $113,663,000 in 2016, $102,356,000 in 2015 and $104,297,000 in 2014. Minimum lease payments under noncancelable operating leases are presented in note 21. Minimum lease payments required under capital leases are not material.

Capitalized servicing assets

Capitalized servicing assets	12 Months Ended
	Dec. 31, 2016
Transfers And Servicing [Abstract]
Capitalized servicing assets	7. Capitalized servicing assets Changes in capitalized servicing assets were as follows: Residential Mortgage Loans Commercial Mortgage Loans For the Year Ended December 31, 2016 2015 2014 2016 2015 2014 (In thousands) Beginning balance $ 118,303 $ 109,871 $ 126,377 $ 83,692 $ 72,939 $ 72,499 Originations 28,618 35,556 28,285 40,117 29,914 15,922 Purchases 638 243 289 — — 730 Amortization (30,208 ) (27,367 ) (45,080 ) (20,045 ) (19,161 ) (16,212 ) 117,351 118,303 109,871 103,764 83,692 72,939 Valuation allowance — — — — — — Ending balance, net $ 117,351 $ 118,303 $ 109,871 $ 103,764 $ 83,692 $ 72,939 Other Total For the Year Ended December 31, 2016 2015 2014 2016 2015 2014 (In thousands) Beginning balance $ 729 $ 4,107 $ 11,225 $ 202,724 $ 186,917 $ 210,101 Originations — — — 68,735 65,470 44,207 Purchases — — — 638 243 1,019 Amortization (729 ) (3,378 ) (7,118 ) (50,982 ) (49,906 ) (68,410 ) — 729 4,107 221,115 202,724 186,917 Valuation allowance — — — — — — Ending balance, net $ — $ 729 $ 4,107 $ 221,115 $ 202,724 $ 186,917 Residential mortgage loans serviced for others were $53.2 billion at December 31, 2016, $61.7 billion at December 31, 2015 and $67.2 billion at December 31, 2014. Reflected in residential mortgage loans serviced for others were loans sub-serviced for others of $30.4 billion, $37.8 billion and $42.1 billion at December 31, 2016, 2015, and 2014, respectively. Commercial mortgage loans serviced for others were $11.8 billion at December 31, 2016, $11.0 billion at December 31, 2015 and $11.3 billion at December 31, 2014. The estimated fair value of capitalized residential mortgage loan servicing assets was approximately $235 million at December 31, 2016 and $249 million at December 31, 2015. The fair value of capitalized residential mortgage loan servicing assets was estimated using weighted-average discount rates of 12.2% and 12.4% at December 31, 2016 and 2015, respectively, and contemporaneous prepayment assumptions that vary by loan type. At December 31, 2016 and 2015, the discount rate represented a weighted-average option-adjusted spread (“OAS”) of 1095 basis points (hundredths of one percent) and 1119 basis points, respectively, over market implied forward London Interbank Offered Rates (“LIBOR”). The estimated fair value of capitalized residential mortgage loan servicing rights may vary significantly in subsequent periods due to changing interest rates and the effect thereof on prepayment speeds. The estimated fair value of capitalized commercial mortgage loan servicing assets was approximately $119 million and $99 million at December 31, 2016 and 2015, respectively. An 18% discount rate was used to estimate the fair value of capitalized commercial mortgage loan servicing rights at December 31, 2016 and 2015 with no prepayment assumptions because, in general, the servicing agreements allow the Company to share in customer loan prepayment fees and thereby recover the remaining carrying value of the capitalized servicing rights associated with such loan. The Company’s ability to realize the carrying value of capitalized commercial mortgage servicing rights is more dependent on the borrowers’ abilities to repay the underlying loans than on prepayments or changes in interest rates. The key economic assumptions used to determine the fair value of significant portfolios of capitalized servicing rights at December 31, 2016 and the sensitivity of such value to changes in those assumptions are summarized in the table that follows. Those calculated sensitivities are hypothetical and actual changes in the fair value of capitalized servicing rights may differ significantly from the amounts presented herein. The effect of a variation in a particular assumption on the fair value of the servicing rights is calculated without changing any other assumption. In reality, changes in one factor may result in changes in another which may magnify or counteract the sensitivities. The changes in assumptions are presumed to be instantaneous. Residential Commercial Weighted-average prepayment speeds 11.30 % Impact on fair value of 10% adverse change $ (8,525,000 ) Impact on fair value of 20% adverse change (16,390,000 ) Weighted-average OAS 10.95 % Impact on fair value of 10% adverse change $ (7,106,000 ) Impact on fair value of 20% adverse change (13,779,000 ) Weighted-average discount rate 18.00 % Impact on fair value of 10% adverse change $ (5,285,000 ) Impact on fair value of 20% adverse change (10,186,000 )

Goodwill and other intangible a

Goodwill and other intangible assets	12 Months Ended
	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and other intangible assets	8. Goodwill and other intangible assets In accordance with GAAP, the Company does not amortize goodwill, however, core deposit and other intangible assets are amortized over the estimated life of each respective asset. Total amortizing intangible assets were comprised of the following: Gross Carrying Amount Accumulated Amortization Net Carrying Amount (In thousands) December 31, 2016 Core deposit $ 887,459 $ 789,988 $ 97,471 Other 177,268 177,084 184 Total $ 1,064,727 $ 967,072 $ 97,655 December 31, 2015 Core deposit $ 887,459 $ 750,624 $ 136,835 Other 177,268 173,835 3,433 Total $ 1,064,727 $ 924,459 $ 140,268 Amortization of core deposit and other intangible assets was generally computed using accelerated methods over original amortization periods of five to ten years. The weighted-average original amortization period was approximately eight years. The remaining weighted-average amortization period as of December 31, 2016 was approximately six years. Amortization expense for core deposit and other intangible assets was $42,613,000, $26,424,000 and $33,824,000 for the years ended December 31, 2016, 2015 and 2014, respectively. Estimated amortization expense in future years for such intangible assets is as follows: (In thousands) Year ending December 31: 2017 $ 30,305 2018 23,462 2019 18,026 2020 13,323 2021 8,621 Later years 3,918 $ 97,655 In accordance with GAAP, the Company completed annual goodwill impairment tests as of October 1, 2016, 2015 and 2014. For purposes of testing for impairment, the Company assigned all recorded goodwill to the reporting units originally intended to benefit from past business combinations, which has historically been the Company’s core relationship business reporting units. Goodwill was generally assigned based on the implied fair value of the acquired goodwill applicable to the benefited reporting units at the time of each respective acquisition. The implied fair value of the goodwill was determined as the difference between the estimated incremental overall fair value of the reporting unit and the estimated fair value of the net assets assigned to the reporting unit as of each respective acquisition date. To test for goodwill impairment at each evaluation date, the Company compared the estimated fair value of each of its reporting units to their respective carrying amounts and certain other assets and liabilities assigned to the reporting unit, including goodwill and core deposit and other intangible assets. The methodologies used to estimate fair values of reporting units as of the acquisition dates and as of the evaluation dates were similar. For the Company’s core customer relationship business reporting units, fair value was estimated as the present value of the expected future cash flows of the reporting unit. Based on the results of the goodwill impairment tests, the Company concluded that the amount of recorded goodwill was not impaired at the respective testing dates. A summary of goodwill assigned to each of the Company’s reportable segments as of December 31, 2016 and 2015 for purposes of testing for impairment is as follows. (In thousands) Business Banking $ 864,366 Commercial Banking 1,401,873 Commercial Real Estate 654,389 Discretionary Portfolio — Residential Mortgage Banking — Retail Banking 1,309,191 All Other 363,293 Total $ 4,593,112

Borrowings

Borrowings	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Borrowings	9. Borrowings The amounts and interest rates of short-term borrowings were as follows: Federal Funds Purchased and Repurchase Agreements Other Short-term Borrowings Total (Dollars in thousands) At December 31, 2016 Amount outstanding $ 163,442 — $ 163,442 Weighted-average interest rate 0.32 % — 0.32 % For the year ended December 31, 2016 Highest amount at a month-end $ 225,940 $ 1,974,013 Daily-average amount outstanding 203,853 689,969 $ 893,822 Weighted-average interest rate 0.28 % 0.44 % 0.41 % At December 31, 2015 Amount outstanding $ 150,546 $ 1,981,636 $ 2,132,182 Weighted-average interest rate 0.06 % 0.43 % 0.40 % For the year ended December 31, 2015 Highest amount at a month-end $ 202,951 $ 1,989,257 Daily-average amount outstanding 187,167 360,838 $ 548,005 Weighted-average interest rate 0.08 % 0.43 % 0.31 % At December 31, 2014 Amount outstanding $ 192,676 — $ 192,676 Weighted-average interest rate 0.07 % — 0.07 % For the year ended December 31, 2014 Highest amount at a month-end $ 280,350 — Daily-average amount outstanding 214,736 — $ 214,736 Weighted-average interest rate 0.05 % — 0.05 % Short-term borrowings have a stated maturity of one year or less at the date the Company enters into the obligation. In general, federal funds purchased and short-term repurchase agreements outstanding at December 31, 2016 matured on the next business day following year-end. Other short-term borrowings at December 31, 2015 represent borrowings from the FHLB of New York that were assumed in the acquisition of Hudson City. Those borrowings matured at various dates during 2016. At December 31, 2016, M&T Bank had lines of credit under formal agreements as follows: (In thousands) Outstanding borrowings $ 1,154,828 Unused 32,573,956 At December 31, 2016, M&T Bank had borrowing facilities available with the FHLBs whereby M&T Bank could borrow up to approximately $22.5 billion. Additionally, M&T Bank had an available line of credit with the Federal Reserve Bank of New York totaling approximately $11.2 billion at December 31, 2016. M&T Bank is required to pledge loans and investment securities as collateral for these borrowing facilities. Long-term borrowings were as follows: December 31, 2016 2015 (In thousands) Senior notes of M&T Bank: Variable rate due 2016 $ — $ 300,000 Variable rate due 2017 550,000 550,000 1.25% due 2017 499,999 499,984 1.40% due 2017 749,946 749,851 1.45% due 2018 501,829 503,527 2.25% due 2019 649,012 648,628 2.30% due 2019 749,473 749,219 2.10% due 2020 749,735 749,650 2.90% due 2025 749,320 749,236 Advances from FHLB: Fixed rates 1,154,737 1,158,216 Agreements to repurchase securities 1,084,694 1,899,281 Subordinated notes of Wilmington Trust Corporation (a wholly owned subsidiary of M&T): 8.50% due 2018 207,651 213,417 Subordinated notes of M&T Bank: 6.625% due 2017 409,526 419,800 5.585% due 2020, variable rate commenced 2015 409,361 409,361 5.629% due 2021, variable rate commenced 2016 500,000 518,797 Junior subordinated debentures of M&T associated with preferred capital securities: Fixed rates: BSB Capital Trust I — 8.125%, due 2028 15,659 15,635 Provident Trust I — 8.29%, due 2028 26,293 25,817 Southern Financial Statutory Trust I — 10.60%, due 2030 6,620 6,583 Variable rates: First Maryland Capital I — due 2027 146,256 145,717 First Maryland Capital II — due 2027 147,954 147,291 Allfirst Asset Trust — due 2029 96,494 96,349 BSB Capital Trust III — due 2033 15,464 15,464 Provident Statutory Trust III — due 2033 53,834 53,244 Southern Financial Capital Trust III — due 2033 7,968 7,889 Other 12,010 20,902 $ 9,493,835 $ 10,653,858 The variable rate senior notes of M&T Bank pay interest quarterly at rates that are indexed to the three-month LIBOR. The contractual interest rates for those notes ranged from 1.18% to 1.26% at December 31, 2016 and from 0.62% to 0.75% at December 31, 2015. The weighted-average contractual interest rates payable were 1.22% at December 31, 2016 and 0.69% at December 31, 2015. Long-term fixed rate advances from the FHLB had contractual interest rates ranging from 1.17% to 7.32% with a weighted-average contractual interest rate of 1.65% at December 31, 2016 and 1.66% at December 31, 2015. Advances from the FHLB mature at various dates through 2035 and are secured by residential real estate loans, commercial real estate loans and investment securities. Long-term agreements to repurchase securities had contractual interest rates that ranged from 3.65% to 4.58% at December 31, 2016 and from 3.61% to 4.58% at December 31, 2015. The weighted-average contractual interest rates payable were 4.05% at December 31, 2016 and 4.00% at December 31, 2015. The agreements reflect various repurchase dates through 2020, however, the contractual maturities of the underlying investment securities extend beyond such repurchase dates. The agreements are subject to legally enforceable master netting arrangements, however, the Company has not offset any amounts related to these agreements in its consolidated financial statements. The Company posted collateral consisting primarily of government guaranteed mortgage-backed securities of $1.1 billion and $2.0 billion at December 31, 2016 and 2015, respectively. The subordinated notes of M&T Bank and Wilmington Trust Corporation are unsecured and are subordinate to the claims of other creditors of those entities. The subordinated notes of M&T Bank that mature in 2020 converted to variable rate notes in December 2015. These notes now pay interest monthly at a rate that is indexed to the one-month LIBOR. The contractual interest rates were 1.97% and 1.64% at December 31, 2016 and 2015, respectively. The subordinated notes of M&T Bank that mature in 2021 converted to variable rate notes in December 2016. These notes now pay interest quarterly at a rate that is indexed to the three-month LIBOR. The contractual interest rate was 1.57% at December 31, 2016. The fixed and variable rate junior subordinated deferrable interest debentures of M&T (“Junior Subordinated Debentures”) are held by various trusts and were issued in connection with the issuance by those trusts of preferred capital securities (“Capital Securities”) and common securities (“Common Securities”). The proceeds from the issuances of the Capital Securities and the Common Securities were used by the trusts to purchase the Junior Subordinated Debentures. The Common Securities of each of those trusts are wholly owned by M&T and are the only class of each trust’s securities possessing general voting powers. The Capital Securities represent preferred undivided interests in the assets of the corresponding trust. Under the Federal Reserve Board’s risk-based capital guidelines, in 2015 only 25% of then-outstanding Capital Securities were included in Tier 1 capital and beginning in 2016 none of the securities were included in M&T’s Tier 1 regulatory capital, but do qualify for inclusion in Tier 2 regulatory capital. The variable rate Junior Subordinated Debentures pay interest quarterly at rates that are indexed to the three-month LIBOR. Those rates ranged from 1.74% to 4.23% at December 31, 2016 and from 1.18% to 3.67% at December 31, 2015. The weighted-average variable rates payable on those Junior Subordinated Debentures were 2.33% at December 31, 2016 and 1.78% at December 31, 2015. Holders of the Capital Securities receive preferential cumulative cash distributions unless M&T exercises its right to extend the payment of interest on the Junior Subordinated Debentures as allowed by the terms of each such debenture, in which case payment of distributions on the respective Capital Securities will be deferred for comparable periods. During an extended interest period, M&T may not pay dividends or distributions on, or repurchase, redeem or acquire any shares of its capital stock. In general, the agreements governing the Capital Securities, in the aggregate, provide a full, irrevocable and unconditional guarantee by M&T of the payment of distributions on, the redemption of, and any liquidation distribution with respect to the Capital Securities. The obligations under such guarantee and the Capital Securities are subordinate and junior in right of payment to all senior indebtedness of M&T. The Capital Securities will remain outstanding until the Junior Subordinated Debentures are repaid at maturity, are redeemed prior to maturity or are distributed in liquidation to the trusts. The Capital Securities are mandatorily redeemable in whole, but not in part, upon repayment at the stated maturity dates (ranging from 2027 to 2033) of the Junior Subordinated Debentures or the earlier redemption of the Junior Subordinated Debentures in whole upon the occurrence of one or more events set forth in the indentures relating to the Capital Securities, and in whole or in part at any time after an optional redemption prior to contractual maturity contemporaneously with the optional redemption of the related Junior Subordinated Debentures in whole or in part, subject to possible regulatory approval. Long-term borrowings at December 31, 2016 mature as follows: (In thousands) Year ending December 31: 2017 $ 3,442,484 2018 714,358 2019 2,299,502 2020 1,269,939 2021 500,144 Later years 1,267,408 $ 9,493,835

Shareholders' equity

Shareholders' equity	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Shareholders' equity	10. Shareholders’ equity M&T is authorized to issue 1,000,000 shares of preferred stock with a $1.00 par value per share. Preferred shares outstanding rank senior to common shares both as to dividends and liquidation preference, but have no general voting rights. Issued and outstanding preferred stock of M&T is presented below: December 31, 2016 December 31, 2015 Shares Issued and Outstanding Carrying value Shares Issued and Outstanding Carrying value (Dollars in thousands) Series A (a) Fixed Rate Cumulative Perpetual Preferred Stock, $1,000 liquidation preference per share 230,000 $ 230,000 230,000 $ 230,000 Series C (a) Fixed Rate Cumulative Perpetual Preferred Stock, $1,000 liquidation preference per share 151,500 $ 151,500 151,500 $ 151,500 Series D (b) Fixed Rate Non-cumulative Perpetual Preferred Stock, $10,000 liquidation preference per share — — 50,000 $ 500,000 Series E (c) Fixed-to-Floating Rate Non-cumulative Perpetual Preferred Stock, $1,000 liquidation preference per share 350,000 $ 350,000 350,000 $ 350,000 Series F (d) Fixed-to-Floating Rate Non-cumulative Perpetual Preferred Stock, $10,000 liquidation preference per share 50,000 $ 500,000 — — (a) Dividends, if declared, are paid at 6.375%. Warrants to purchase M&T common stock at $73.86 per share issued in connection with the Series A preferred stock expire in 2018 and totaled 631,794 and 719,175 at December 31, 2016 and 2015, respectively. (b) The shares were fully redeemed in December 2016, having received the approval of the Federal Reserve to redeem such shares after issuing the Series F preferred stock. (c) Dividends, if declared, are paid semi-annually at a rate of 6.45% through February 14, 2024 and thereafter will be paid quarterly at a rate of the three-month LIBOR plus 361 basis points (hundredths of one percent). The shares are redeemable in whole or in part on or after February 15, 2024. Notwithstanding M&T’s option to redeem the shares, if an event occurs such that the shares no longer qualify as Tier 1 capital, M&T may redeem all of the shares within 90 days following that occurrence. (d) Dividends, if declared, are paid semi-annually at a rate of 5.125% through October 31, 2026 and thereafter will be paid quarterly at a rate of the three-month LIBOR plus 352 basis points. The shares are redeemable in whole or in part on or after November 1, 2026. Notwithstanding M&T’s option to redeem the shares, if an event occurs such that the shares no longer qualify as Tier 1 capital, M&T may redeem all of the shares within 90 days following that occurrence. In addition to the Series A warrants mentioned in (a) above, a warrant to purchase 95,383 shares of M&T common stock at $518.96 per share was outstanding at each of December 31, 2016 and 2015. The obligation under that warrant was assumed by M&T in an acquisition.

Stock-based compensation plans

Stock-based compensation plans	12 Months Ended
	Dec. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based compensation plans	11. Stock-based compensation plans Stock-based compensation expense was $65 million in 2016 and 2014, and $67 million in 2015. The Company recognized income tax benefits related to stock-based compensation of $31 million in 2016, $29 million in 2015 and $31 million in 2014. The Company’s equity incentive compensation plan allows for the issuance of various forms of stock-based compensation, including stock options, restricted stock, restricted stock units and performance-based awards. At December 31, 2016 and 2015, respectively, there were 3,667,800 and 3,954,712 shares available for future grant under the Company’s equity incentive compensation plan. Restricted stock awards Restricted stock awards are comprised of restricted stock and restricted stock units. Restricted stock awards granted since 2014 vest over three years. Restricted stock awards granted prior to 2014 vest over four years. A portion of restricted stock awards granted after 2013 require a performance condition to be met before such awards vest. Unrecognized compensation expense associated with restricted stock was $12 million as of December 31, 2016 and is expected to be recognized over a weighted-average period of approximately one year. The Company may issue restricted shares from treasury stock to the extent available or issue new shares. The number of restricted shares issued was 218,341 in 2016, 218,183 in 2015 and 221,822 in 2014, with a weighted-average grant date fair value of $24,085,000 in 2016, $24,726,000 in 2015 and $24,765,000 in 2014. Unrecognized compensation expense associated with restricted stock units was $5 million as of December 31, 2016 and is expected to be recognized over a weighted-average period of approximately one year. The number of restricted stock units issued was 348,297 in 2016, 324,772 in 2015 and 299,525 in 2014, with a weighted-average grant date fair value of $38,795,000, $37,070,000 and $33,406,000, respectively. A summary of restricted stock and restricted stock unit activity follows: Restricted Stock Units Outstanding Weighted- Average Grant Price Restricted Stock Outstanding Weighted- Average Grant Price Unvested at January 1, 2016 968,498 $ 109.38 625,888 $ 103.82 Granted 348,297 111.38 218,341 110.31 Vested (570,509 ) 108.21 (324,981 ) 98.55 Cancelled (6,936 ) 110.90 (19,924 ) 108.15 Unvested at December 31, 2016 739,350 $ 111.21 499,324 $ 109.92 Stock option awards Stock options issued generally vested over four years and are exercisable over terms not exceeding ten years and one day. The Company used an option pricing model to estimate the grant date present value of stock options granted. Stock options granted in 2016, 2015 and 2014 were not significant. A summary of stock option activity follows: Weighted-Average Stock Options Outstanding Exercise Price Life (In Years) Aggregate Intrinsic Value (In thousands) Outstanding at January 1, 2016 4,223,710 $ 126.65 Granted 200 110.18 Exercised (1,694,440 ) 106.68 Expired (934,879 ) 140.75 Outstanding at December 31, 2016 1,594,591 $ 139.60 1.5 $ 39,326 Exercisable at December 31, 2016 1,594,149 $ 139.60 1.5 $ 39,305 For 2016, 2015 and 2014, M&T received $172 million, $93 million and $127 million, respectively, in cash and realized tax benefits from the exercise of stock options of $15 million, $6 million and $9 million, respectively. The intrinsic value of stock options exercised during those periods was $42 million, $17 million and $26 million, respectively. As of December 31, 2016, the amount of unrecognized compensation cost related to non-vested stock options was not significant. The total grant date fair value of stock options vested during 2016, 2015 and 2014 was not significant. Upon the exercise of stock options, the Company may issue shares from treasury stock to the extent available or issue new shares. Stock purchase plan The stock purchase plan provides eligible employees of the Company with the right to purchase shares of M&T common stock at a discount through accumulated payroll deductions. In connection with the employee stock purchase plan, 2,500,000 shares of M&T common stock were authorized for issuance under a plan adopted in 2013. There were 97,880 shares issued in 2016, 89,384 shares issued in 2015 and 85,761 shares issued in 2014. For 2016, 2015 and 2014, M&T received $9,528,000, $9,296,000 and $8,607,000, respectively, in cash for shares purchased through the employee stock purchase plan. Compensation expense recognized for the stock purchase plan was not significant in 2016, 2015 or 2014. Deferred bonus plan The Company provided a deferred bonus plan pursuant to which eligible employees could elect to defer all or a portion of their annual incentive compensation awards and allocate such awards to several investment options, including M&T common stock. Participants could elect the timing of distributions from the plan. Such distributions are payable in cash with the exception of balances allocated to M&T common stock which are distributable in the form of M&T common stock. Shares of M&T common stock distributable pursuant to the terms of the deferred bonus plan were 23,188 and 26,365 at December 31, 2016 and 2015, respectively. The obligation to issue shares is included in “common stock issuable” in the consolidated balance sheet. Directors’ stock plan The Company maintains a compensation plan for non-employee members of the Company’s boards of directors and directors advisory councils that allows such members to receive all or a portion of their compensation in shares of M&T common stock. Through December 31, 2016, 243,652 shares had been issued in connection with the directors’ stock plan. Through acquisitions, the Company assumed obligations to issue shares of M&T common stock related to deferred directors compensation plans. Shares of common stock issuable under such plans were 9,215 and 10,279 at December 31, 2016 and 2015, respectively. The obligation to issue shares is included in “common stock issuable” in the consolidated balance sheet.

Pension plans and other postret

Pension plans and other postretirement benefits	12 Months Ended
	Dec. 31, 2016
Compensation And Retirement Disclosure [Abstract]
Pension plans and other postretirement benefits	12. Pension plans and other postretirement benefits The Company provides defined benefit pension and other postretirement benefits (including health care and life insurance benefits) to qualified retired employees. The Company uses a December 31 measurement date for all of its plans. Net periodic pension expense for defined benefit plans consisted of the following: Year Ended December 31 2016 2015 2014 (In thousands) Service cost $ 25,037 $ 24,372 $ 20,520 Interest cost on benefit obligation 83,410 72,731 69,162 Expected return on plan assets (108,473 ) (96,155 ) (91,568 ) Amortization of prior service credit (3,228 ) (6,005 ) (6,552 ) Recognized net actuarial loss 30,145 44,825 14,494 Net periodic pension expense $ 26,891 $ 39,768 $ 6,056 Net other postretirement benefits expense for defined benefit plans consisted of the following: Year Ended December 31 2016 2015 2014 (In thousands) Service cost $ 1,595 $ 914 $ 605 Interest cost on benefit obligation 4,971 2,995 2,778 Amortization of prior service credit (1,359 ) (1,359 ) (1,359 ) Recognized net actuarial loss 60 106 — Net other postretirement benefits expense $ 5,267 $ 2,656 $ 2,024 Data relating to the funding position of the defined benefit plans were as follows: Pension Benefits Other Postretirement Benefits 2016 2015 2016 2015 (In thousands) Change in benefit obligation: Benefit obligation at beginning of year $ 2,004,531 $ 1,813,409 $ 121,497 $ 67,502 Service cost 25,037 24,372 1,595 914 Interest cost 83,410 72,731 4,971 2,995 Plan participants’ contributions — — 3,085 2,619 Amendments and curtailments (28,308 ) — — — Actuarial (gain) loss 4,827 (83,593 ) (10,553 ) (2,431 ) Business combinations — 247,340 — 56,539 Medicare Part D reimbursement — — 592 420 Benefits paid (82,339 ) (69,728 ) (11,265 ) (7,061 ) Benefit obligation at end of year 2,007,158 2,004,531 109,922 121,497 Change in plan assets: Fair value of plan assets at beginning of year 1,625,134 1,505,661 — — Actual return on plan assets 88,564 (14,069 ) — — Employer contributions 10,772 8,367 7,588 4,022 Plan participants’ contributions — — 3,085 2,619 Business combinations — 194,903 — — Medicare Part D reimbursement — — 592 420 Benefits paid (82,339 ) (69,728 ) (11,265 ) (7,061 ) Fair value of plan assets at end of year 1,642,131 1,625,134 — — Funded status $ (365,027 ) $ (379,397 ) $ (109,922 ) $ (121,497 ) Accrued liabilities recognized in the consolidated balance sheet $ (365,027 ) $ (379,397 ) $ (109,922 ) $ (121,497 ) Amounts recognized in accumulated other comprehensive income (“AOCI”) were: Net loss (gain) $ 460,562 $ 494,279 $ (6,413 ) $ 4,200 Net prior service cost (credit) 3,505 277 (7,737 ) (9,096 ) Pre-tax adjustment to AOCI 464,067 494,556 (14,150 ) (4,896 ) Taxes (182,611 ) (194,608 ) 5,568 1,927 Net adjustment to AOCI $ 281,456 $ 299,948 $ (8,582 ) $ (2,969 ) The Company has an unfunded supplemental pension plan for certain key executives and others. The projected benefit obligation and accumulated benefit obligation included in the preceding data related to such plan were $160,433,000 as of December 31, 2016 and $161,657,000 as of December 31, 2015. The accumulated benefit obligation for all defined benefit pension plans was $1,979,225,000 and $1,951,425,000 at December 31, 2016 and 2015, respectively. GAAP requires an employer to recognize in its balance sheet as an asset or liability the overfunded or underfunded status of a defined benefit postretirement plan, measured as the difference between the fair value of plan assets and the benefit obligation. For a pension plan, the benefit obligation is the projected benefit obligation; for any other postretirement benefit plan, such as a retiree health care plan, the benefit obligation is the accumulated postretirement benefit obligation. Gains or losses and prior service costs or credits that arise during the period, but are not included as components of net periodic benefit expense, are recognized as a component of other comprehensive income. As indicated in the preceding table, as of December 31, 2016 the Company recorded a minimum liability adjustment of $449,916,000 ($464,066,000 related to pension plans and $(14,150,000) related to other postretirement benefits) with a corresponding reduction of shareholders’ equity, net of applicable deferred taxes, of $272,874,000. In aggregate, the benefit plans realized a net gain during 2016 that allowed the Company to decrease its minimum liability adjustment from that which was recorded at December 31, 2015 by $39,743,000 with a corresponding increase to shareholders’ equity that, net of applicable deferred taxes, was $24,105,000. The net gain reflects the amortization of unrealized losses previously recorded in other comprehensive income and the reduction of future benefit accruals under the former Hudson City retirement plan upon its merger with the Company’s qualified pension plan as of December 31, 2016. The table below reflects the changes in plan assets and benefit obligations recognized in other comprehensive income related to the Company’s postretirement benefit plans. Pension Plans Other Postretirement Benefit Plans Total (In thousands) 2016 Net loss (gain) $ 24,736 $ (10,553 ) $ 14,183 Amendments and curtailments (28,308 ) — (28,308 ) Amortization of prior service credit 3,228 1,359 4,587 Amortization of actuarial loss (30,145 ) (60 ) (30,205 ) Total recognized in other comprehensive income, pre-tax $ (30,489 ) $ (9,254 ) $ (39,743 ) 2015 Net loss (gain) $ 26,631 $ (2,431 ) $ 24,200 Amortization of prior service credit 6,005 1,359 7,364 Amortization of actuarial loss (44,825 ) (106 ) (44,931 ) Total recognized in other comprehensive income, pre-tax $ (12,189 ) $ (1,178 ) $ (13,367 ) The following table reflects the amortization of amounts in accumulated other comprehensive income expected to be recognized as components of net periodic benefit expense during 2017: Pension Plans Other Postretirement Benefit Plans (In thousands) Amortization of net prior service cost (credit) $ 557 $ (1,359 ) Amortization of net loss (gain) 27,196 (44 ) The Company also provides a qualified defined contribution pension plan to eligible employees who were not participants in the defined benefit pension plan as of December 31, 2005 and to other employees who have elected to participate in the defined contribution plan. The Company makes contributions to the defined contribution plan each year in an amount that is based on an individual participant’s total compensation (generally defined as total wages, incentive compensation, commissions and bonuses) and years of service. Participants do not contribute to the defined contribution pension plan. Pension expense recorded in 2016, 2015 and 2014 associated with the defined contribution pension plan was approximately $25 million, $23 million and $22 million, respectively. Assumptions The assumed weighted-average rates used to determine benefit obligations at December 31 were: Pension Benefits Other Postretirement Benefits 2016 2015 2016 2015 Discount rate 4.00 % 4.25 % 4.00 % 4.25 % Rate of increase in future compensation levels 4.39 % 4.37 % — — The assumed weighted-average rates used to determine net benefit expense for the years ended December 31 were: Pension Benefits Other Postretirement Benefits 2016 2015 2014 2016 2015 2014 Discount rate 4.25 % 4.00 % 4.75 % 4.25 % 4.00 % 4.75 % Long-term rate of return on plan assets 6.50 % 6.50 % 6.50 % — — — Rate of increase in future compensation levels 4.37 % 4.39 % 4.42 % — — — The expected long-term rate of return assumption as of each measurement date was developed through analysis of historical market returns, current market conditions, anticipated future asset allocations, the funds’ past experience, and expectations on potential future market returns. The expected rate of return assumption represents a long-term average view of the performance of the plan assets, a return that may or may not be achieved during any one calendar year. For measurement of other postretirement benefits, a 6.50% annual rate of increase in the per capita cost of covered health care benefits was assumed for 2017. The rate was assumed to decrease to 5.00% over 12 years. A one-percentage point change in assumed health care cost trend rates would have had the following effects: +1% -1% (In thousands) Increase (decrease) in: Service and interest cost $ 106 $ (87 ) Accumulated postretirement benefit obligation 1,548 (1,400 ) Plan assets The Company’s policy is to invest the pension plan assets in a prudent manner for the purpose of providing benefit payments to participants and mitigating reasonable expenses of administration. The Company’s investment strategy is designed to provide a total return that, over the long-term, places an emphasis on the preservation of capital. The strategy attempts to maximize investment returns on assets at a level of risk deemed appropriate by the Company while complying with applicable regulations and laws. The investment strategy utilizes asset diversification as a principal determinant for establishing an appropriate risk profile while emphasizing total return realized from capital appreciation, dividends and interest income. The target allocations for plan assets are generally 25 to 60 percent equity securities, 10 to 65 percent debt securities, and 10 to 85 percent money-market funds/cash equivalents and other investments, although holdings could be more or less than these general guidelines based on market conditions at the time and actions taken or recommended by the investment managers providing advice to the Company. Assets are managed by a combination of internal and external investment managers. Equity securities may include investments in domestic and international equities, through individual securities, mutual funds and exchange-traded funds. Debt securities may include investments in corporate bonds of companies from diversified industries, mortgage-backed securities guaranteed by government agencies and U.S. Treasury securities, through individual securities and mutual funds. Additionally, the Company’s defined benefit pension plan held $234,969,000 (14.3% of total assets) of real estate, private investments, hedge funds and other investments at December 31, 2016. Returns on invested assets are periodically compared with target market indices for each asset type to aid management in evaluating such returns. Furthermore, management regularly reviews the investment policy and may, if deemed appropriate, make changes to the target allocations noted above. The fair values of the Company’s pension plan assets at December 31, 2016, by asset category, were as follows: Fair Value Measurement of Plan Assets At December 31, 2016 Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Asset category: Money-market funds $ 39,556 $ 35,562 $ 3,994 $ — Equity securities: M&T 164,474 164,474 — — Domestic(a) 200,595 200,595 — — International(b) 14,364 14,364 — — Mutual funds: Domestic(a) 250,472 250,472 — — International(b) 290,172 290,172 — — 920,077 920,077 — — Debt securities: Corporate(c) 104,909 — 104,909 — Government 121,869 — 121,869 — International 13,073 — 13,073 — Mutual funds: Domestic(d) 205,847 205,847 — — 445,698 205,847 239,851 — Other: Diversified mutual fund 92,691 92,691 — — Real estate partnerships 3,112 768 — 2,344 Private equity 21,924 — — 21,924 Hedge funds 106,250 85,270 — 20,980 Guaranteed deposit fund 10,992 — — 10,992 234,969 178,729 — 56,240 Total(e) $ 1,640,300 $ 1,340,215 $ 243,845 $ 56,240 The fair values of the Company’s pension plan assets at December 31, 2015, by asset category, were as follows: Fair Value Measurement of Plan Assets At December 31, 2015 Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Asset category: Money-market funds $ 69,634 $ 37,958 $ 31,676 $ — Equity securities: M&T 148,800 148,800 — — Domestic(a) 106,993 106,993 — — International(b) 9,433 9,433 — — Mutual funds: Domestic(a) 445,663 445,663 — — International(b) 348,869 348,869 — — 1,059,758 1,059,758 — — Debt securities: Corporate(c) 105,499 — 105,499 — Government 120,346 — 120,346 — International 7,492 — 7,492 — Mutual funds: Domestic(d) 51,028 51,028 — — 284,365 51,028 233,337 — Other: Diversified mutual fund 70,343 70,343 — — Real estate partnerships 2,787 — — 2,787 Private equity 5,603 — — 5,603 Hedge funds 119,549 81,861 — 37,688 Guaranteed deposit fund 11,596 — — 11,596 209,878 152,204 — 57,674 Total(e) $ 1,623,635 $ 1,300,948 $ 265,013 $ 57,674 (a) This category is comprised of equities of companies primarily within the mid-cap and large-cap sectors of the U.S. economy and range across diverse industries. (b) This category is comprised of equities in companies primarily within the mid-cap and large-cap sectors of international markets mainly in developed markets in Europe and the Pacific Rim. (c) This category represents investment grade bonds of U.S. issuers from diverse industries. (d) Approximately 75% of the mutual funds were invested in investment grade bonds and 25% in high-yielding bonds at December 31, 2016. Approximately 33% of the mutual funds were invested in investment grade bonds and 67% in high-yielding bonds at December 31, 2015. The holdings within the funds were spread across diverse industries. (e) Excludes dividends and interest receivable totaling $1,831,000 and $1,499,000 at December 31, 2016 and 2015, respectively. Pension plan assets included common stock of M&T with a fair value of $164,474,000 (10.0% of total plan assets) at December 31, 2016 and $148,800,000 (9.2% of total plan assets) at December 31, 2015. No other investment in securities of a non-U.S. Government or government agency issuer exceeded ten percent of plan assets at December 31, 2016. Assets subject to Level 3 valuations did not constitute a significant portion of plan assets at December 31, 2016 or December 31, 2015. The changes in Level 3 pension plan assets measured at estimated fair value on a recurring basis during the year ended December 31, 2016 were as follows: Balance – January 1, 2016 Purchases (Sales) Total Realized/ Unrealized Gains (Losses) Balance – December 31, 2016 (In thousands) Other Private real estate $ 2,787 $ (1,111 ) $ 668 $ 2,344 Private equity 5,603 17,177 (856 ) 21,924 Hedge funds 37,688 (16,337 ) (371 ) 20,980 Guaranteed deposit fund 11,596 (540 ) (64 ) 10,992 Total $ 57,674 $ (811 ) $ (623 ) $ 56,240 The Company makes contributions to its funded qualified defined benefit pension plan as required by government regulation or as deemed appropriate by management after considering factors such as the fair value of plan assets, expected returns on such assets, and the present value of benefit obligations of the plan. Subject to the impact of actual events and circumstances that may occur in 2017, the Company may make contributions to the qualified defined benefit pension plan in 2017, but the amount of any such contribution has not yet been determined. The Company did not make any contributions to the plan in 2016 or 2015. The Company regularly funds the payment of benefit obligations for the supplemental defined benefit pension and postretirement benefit plans because such plans do not hold assets for investment. Payments made by the Company for supplemental pension benefits were $10,772,000 and $8,367,000 in 2016 and 2015, respectively. Payments made by the Company for postretirement benefits were $7,588,000 and $4,022,000 in 2016 and 2015, respectively. Payments for supplemental pension and other postretirement benefits for 2017 are not expected to differ from those made in 2016 by an amount that will be material to the Company’s consolidated financial position. Estimated benefits expected to be paid in future years related to the Company’s defined benefit pension and other postretirement benefits plans are as follows: Pension Benefits Other Postretirement Benefits (In thousands) Year ending December 31: 2017 $ 81,927 $ 8,142 2018 85,715 8,220 2019 91,819 8,251 2020 96,465 8,259 2021 101,698 8,235 2022 through 2026 568,830 40,282 The Company has a retirement savings plan (“RSP”) that is a defined contribution plan in which eligible employees of the Company may defer up to 50% of qualified compensation via contributions to the plan. The Company makes an employer matching contribution in an amount equal to 75% of an employee’s contribution, up to 4.5% of the employee’s qualified compensation. Employees’ accounts, including employee contributions, employer matching contributions and accumulated earnings thereon, are at all times fully vested and nonforfeitable. Employee benefits expense resulting from the Company’s contributions to the RSP totaled $36,766,000, $34,145,000 and $32,466,000 in 2016, 2015 and 2014, respectively.

Income taxes

Income taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income taxes	13. Income taxes The components of income tax expense were as follows: Year Ended December 31 2016 2015 2014 (In thousands) Current Federal $ 428,750 $ 130,349 $ 378,978 State and city 95,426 21,549 50,790 Total current 524,176 151,898 429,768 Deferred Federal 147,662 324,317 65,503 State and city 26,351 72,279 27,345 Total deferred 174,013 396,596 92,848 Amortization of investments in qualified affordable housing projects 45,095 46,531 53,383 Total income taxes applicable to pre-tax income $ 743,284 $ 595,025 $ 575,999 The Company files a consolidated federal income tax return reflecting taxable income earned by all domestic subsidiaries. In prior years, applicable federal tax law allowed certain financial institutions the option of deducting as bad debt expense for tax purposes amounts in excess of actual losses. In accordance with GAAP, such financial institutions were not required to provide deferred income taxes on such excess. Recapture of the excess tax bad debt reserve established under the previously allowed method will result in taxable income if M&T Bank fails to maintain bank status as defined in the Internal Revenue Code or charges are made to the reserve for other than bad debt losses. At December 31, 2016, M&T Bank’s tax bad debt reserve for which no federal income taxes have been provided was $137,121,000. No actions are planned that would cause this reserve to become wholly or partially taxable. Income taxes attributable to gains or losses on bank investment securities were an expense of $11,929,000 in 2016. There were no significant gains or losses on bank investment securities in 2015 or 2014. No alternative minimum tax expense was recognized in 2016, 2015 or 2014. Total income taxes differed from the amount computed by applying the statutory federal income tax rate to pre-tax income as follows: Year Ended December 31 2016 2015 2014 (In thousands) Income taxes at statutory federal income tax rate $ 720,439 $ 586,142 $ 574,786 Increase (decrease) in taxes: Tax-exempt income (35,364 ) (33,102 ) (31,752 ) State and city income taxes, net of federal income tax effect 79,155 60,988 50,788 Qualified affordable housing project federal tax credits, net (15,091 ) (15,297 ) (14,827 ) Other (5,855 ) (3,706 ) (2,996 ) $ 743,284 $ 595,025 $ 575,999 Deferred tax assets (liabilities) were comprised of the following at December 31: 2016 2015 2014 (In thousands) Losses on loans and other assets $ 590,288 $ 637,955 $ 605,273 Retirement benefits 143,067 148,722 120,222 Postretirement and other employee benefits 52,512 55,962 34,052 Incentive and other compensation plans 36,616 60,337 36,450 Interest on loans 61,266 57,640 79,147 Stock-based compensation 52,181 72,090 64,017 Unrealized investment losses 10,741 — — Depreciation and amortization — — 3,527 Other 106,876 162,086 100,999 Gross deferred tax assets 1,053,547 1,194,792 1,043,687 Leasing transactions (266,268 ) (285,074 ) (280,596 ) Unrealized investment gains — (31,121 ) (82,065 ) Capitalized servicing rights (71,108 ) (59,171 ) (46,393 ) Depreciation and amortization (63,959 ) (56,731 ) — Other (87,200 ) (55,611 ) (66,939 ) Gross deferred tax liabilities (488,535 ) (487,708 ) (475,993 ) Net deferred tax asset $ 565,012 $ 707,084 $ 567,694 The Company believes that it is more likely than not that the deferred tax assets will be realized through taxable earnings or alternative tax strategies. The income tax credits shown in the statement of income of M&T in note 25 arise principally from operating losses before dividends from subsidiaries. A reconciliation of the beginning and ending amount of unrecognized tax benefits follows: Federal, State and Local Tax Accrued Interest Unrecognized Income Tax Benefits (In thousands) Gross unrecognized tax benefits at January 1, 2014 $ 14,611 $ 14,696 $ 29,307 Increases as a result of tax positions taken during 2014 769 — 769 Increases as a result of tax positions taken in prior years — 453 453 Decreases as a result of settlements with taxing authorities (4,668 ) (11,280 ) (15,948 ) Gross unrecognized tax benefits at December 31, 2014 10,712 3,869 14,581 Increases as a result of tax positions taken during 2015 8,108 — 8,108 Increases as a result of tax positions taken in prior years — 807 807 Decreases as a result of settlements with taxing authorities (1,515 ) (274 ) (1,789 ) Unrealized tax benefits acquired in a business combination 7,232 3,567 10,799 Gross unrecognized tax benefits at December 31, 2015 24,537 7,969 32,506 Increases as a result of tax positions taken during 2016 12,237 — 12,237 Increases as a result of tax positions taken in prior years — 656 656 Decreases as a result of tax positions taken in prior years (885 ) (710 ) (1,595 ) Gross unrecognized tax benefits at December 31, 2016 $ 35,889 $ 7,915 43,804 Less: Federal, state and local income tax benefits (15,332 ) Net unrecognized tax benefits at December 31, 2016 that, if recognized, would impact the effective income tax rate $ 28,472 The Company’s policy is to recognize interest and penalties, if any, related to unrecognized tax benefits in income taxes in the consolidated statement of income. The balance of accrued interest at December 31, 2016 is included in the table above. The Company’s federal, state and local income tax returns are routinely subject to examinations from various governmental taxing authorities. Such examinations may result in challenges to the tax return treatment applied by the Company to specific transactions. Management believes that the assumptions and judgment used to record tax-related assets or liabilities have been appropriate. Should determinations rendered by tax authorities ultimately indicate that management’s assumptions were inappropriate, the result and adjustments required could have a material effect on the Company’s results of operations. Examinations by the Internal Revenue Service of the Company’s federal income tax returns have been largely concluded through 2015, although under statute the income tax returns from 2010 and 2013 through 2015 could be adjusted. The Company also files income tax returns in over forty states and numerous local jurisdictions. Substantially all material state and local matters have been concluded for years through 2012. It is not reasonably possible to estimate when examinations for any subsequent years will be completed.

Earnings per common share

Earnings per common share	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Earnings per common share	14. Earnings per common share The computations of basic earnings per common share follow: Year Ended December 31 2016 2015 2014 (In thousands, except per share) Income available to common shareholders: Net income $ 1,315,114 $ 1,079,667 $ 1,066,246 Less: Preferred stock dividends(a) (81,270 ) (81,270 ) (75,878 ) Net income available to common equity 1,233,844 998,397 990,368 Less: Income attributable to unvested stock-based compensation awards (10,385 ) (10,708 ) (11,837 ) Net income available to common shareholders $ 1,223,459 $ 987,689 $ 978,531 Weighted-average shares outstanding: Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards 158,121 138,285 132,532 Less: Unvested stock-based compensation awards (1,341 ) (1,482 ) (1,582 ) Weighted-average shares outstanding 156,780 136,803 130,950 Basic earnings per common share $ 7.80 $ 7.22 $ 7.47 (a) Including impact of not as yet declared cumulative dividends. The computations of diluted earnings per common share follow: Year Ended December 31 2016 2015 2014 (In thousands, except per share) Net income available to common equity $ 1,233,844 $ 998,397 $ 990,368 Less: Income attributable to unvested stock-based compensation awards (10,363 ) (10,673 ) (11,787 ) Net income available to common shareholders $ 1,223,481 $ 987,724 $ 978,581 Adjusted weighted-average shares outstanding: Common and unvested stock-based compensation awards 158,121 138,285 132,532 Less: Unvested stock-based compensation awards (1,341 ) (1,482 ) (1,582 ) Plus: Incremental shares from assumed conversion of stock-based compensation awards and warrants to purchase common stock 524 730 894 Adjusted weighted-average shares outstanding 157,304 137,533 131,844 Diluted earnings per common share $ 7.78 $ 7.18 $ 7.42 GAAP defines unvested share-based awards that contain nonforfeitable rights to dividends or dividend equivalents (whether Stock-based compensation awards and warrants to purchase common stock of M&T representing common shares of

Comprehensive income

Comprehensive income	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Comprehensive income	15. Comprehensive income The following tables display the components of other comprehensive income (loss) and amounts reclassified from accumulated other Investment Securities Defined Total With OTTI (a) All Other Benefit Plans Other Amount Before Tax Income Tax Net (In thousands) Balance — January 1, 2016 $ 16,359 $ 62,849 $ (489,660 ) $ (4,093 ) $ (414,545 ) $ 162,918 $ (251,627 ) Other comprehensive income before reclassifications: Unrealized holding gains (losses), net 30,366 (110,316 ) — — (79,950 ) 31,509 (48,441 ) Foreign currency translation adjustment — — — (4,020 ) (4,020 ) 1,406 (2,614 ) Current year benefit plans gains — — 14,125 — 14,125 (5,557 ) 8,568 Total other comprehensive income (loss) before reclassifications 30,366 (110,316 ) 14,125 (4,020 ) (69,845 ) 27,358 (42,487 ) Amounts reclassified from accumulated other comprehensive income that (increase) decrease net income: Amortization of unrealized holding losses on held-to- maturity ("HTM") securities — 3,996 — — 3,996 (b) (1,572 ) 2,424 Gains realized in net income — (30,314 ) — — (30,314 ) (c) 11,925 (18,389 ) Accretion of net gain on terminated cash flow hedges — — — (155 ) (155 ) (d) 61 (94 ) Amortization of prior service credit — — (4,587 ) — (4,587 ) (e) 1,805 (2,782 ) Amortization of actuarial losses — — 30,205 — 30,205 (e) (11,886 ) 18,319 Total reclassifications — (26,318 ) 25,618 (155 ) (855 ) 333 (522 ) Total gain (loss) during the period 30,366 (136,634 ) 39,743 (4,175 ) (70,700 ) 27,691 (43,009 ) Balance — December 31, 2016 $ 46,725 $ (73,785 ) $ (449,917 ) $ (8,268 ) $ (485,245 ) $ 190,609 $ (294,636 ) Investment Securities Defined Total With OTTI (a) All Other Benefit Plans Other Amount Before Tax Income Tax Net (In thousands) Balance — January 1, 2015 $ 7,438 $ 201,828 $ (503,027 ) $ (4,082 ) $ (297,843 ) $ 116,849 $ (180,994 ) Other comprehensive income before reclassifications: Unrealized holding gains (losses), net 8,921 (142,623 ) — — (133,702 ) 52,376 (81,326 ) Foreign currency translation adjustment — — — (1,323 ) (1,323 ) 398 (925 ) Gains on cash flow hedges — — — 1,453 1,453 (572 ) 881 Current year benefit plans losses — — (24,200 ) — (24,200 ) 8,612 (15,588 ) Total other comprehensive income (loss) before reclassifications 8,921 (142,623 ) (24,200 ) 130 (157,772 ) 60,814 (96,958 ) Amounts reclassified from accumulated other comprehensive income that (increase) decrease net income: Amortization of unrealized holding losses on HTM securities — 3,514 — — 3,514 (b) (1,383 ) 2,131 Losses realized in net income — 130 — — 130 (c) (49 ) 81 Accretion of net gain on terminated cash flow hedges — — — (141 ) (141 ) (d) 56 (85 ) Amortization of prior service credit — — (7,364 ) — (7,364 ) (e) 2,620 (4,744 ) Amortization of actuarial losses — — 44,931 — 44,931 (e) (15,989 ) 28,942 Total reclassifications — 3,644 37,567 (141 ) 41,070 (14,745 ) 26,325 Total gain (loss) during the period 8,921 (138,979 ) 13,367 (11 ) (116,702 ) 46,069 (70,633 ) Balance — December 31, 2015 $ 16,359 $ 62,849 $ (489,660 ) $ (4,093 ) $ (414,545 ) $ 162,918 $ (251,627 ) Investment Securities Defined Total With OTTI (a) All Other Benefit Plans Other Amount Before Tax Income Tax Net (In thousands) Balance — January 1, 2014 $ 37,255 $ 18,450 $ (161,617 ) $ 115 $ (105,797 ) $ 41,638 $ (64,159 ) Other comprehensive income before reclassifications: Unrealized holding gains (losses), net (29,818 ) 180,005 — — 150,187 (58,962 ) 91,225 Foreign currency translation adjustment — — — (4,039 ) (4,039 ) 1,432 (2,607 ) Unrealized losses on cash flow hedges — — — (165 ) (165 ) 65 (100 ) Current year benefit plans losses — — (347,993 ) — (347,993 ) 136,587 (211,406 ) Total other comprehensive income (loss) before reclassifications (29,818 ) 180,005 (347,993 ) (4,204 ) (202,010 ) 79,122 (122,888 ) Amounts reclassified from accumulated other comprehensive income that (increase) decrease net income: Amortization of unrealized holding losses on HTM securities 1 3,373 — — 3,374 (b) (1,324 ) 2,050 Amortization of losses on terminated cash flow hedges — — — 7 7 (d) (3 ) 4 Amortization of prior service credit — — (7,911 ) — (7,911 ) (e) 3,105 (4,806 ) Amortization of actuarial losses — — 14,494 — 14,494 (e) (5,689 ) 8,805 Total reclassifications 1 3,373 6,583 7 9,964 (3,911 ) 6,053 Total gain (loss) during the period (29,817 ) 183,378 (341,410 ) (4,197 ) (192,046 ) 75,211 (116,835 ) Balance — December 31, 2014 $ 7,438 $ 201,828 $ (503,027 ) $ (4,082 ) $ (297,843 ) $ 116,849 $ (180,994 ) (a) Other-than-temporary impairment. (b) Included in interest income. (c) Included in gain (loss) on bank investment securities. (d) Included in interest expense. (e) Included in salaries and employee benefits expense. Accumulated other comprehensive income (loss), net consisted of the following: Investment securities Defined Benefit With All Other Plans Other Total (In thousands) Balance at January 1, 2014 $ 22,632 $ 11,294 $ (98,182 ) $ 97 $ (64,159 ) Net gain (loss) during 2014 (18,114 ) 111,389 (207,407 ) (2,703 ) (116,835 ) Balance at December 31, 2014 4,518 122,683 (305,589 ) (2,606 ) (180,994 ) Net gain (loss) during 2015 5,403 (84,517 ) 8,610 (129 ) (70,633 ) Balance at December 31, 2015 9,921 38,166 (296,979 ) (2,735 ) (251,627 ) Net gain (loss) during 2016 18,417 (82,823 ) 24,105 (2,708 ) (43,009 ) Balance at December 31, 2016 $ 28,338 $ (44,657 ) $ (272,874 ) $ (5,443 ) $ (294,636 )

Other income and other expense

Other income and other expense	12 Months Ended
	Dec. 31, 2016
Other Income And Expenses [Abstract]
Other income and other expense	16. Other income and other expense The following items, which exceeded 1% of total interest income and other income in the respective period, were included in either “other revenues from operations” or “other costs of operations” in the consolidated statement of income: Year Ended December 31 2016 2015 2014 (In thousands) Other income: Credit-related fee income $ 70,424 $ 81,558 $ 72,454 Letter of credit fees 52,724 56,708 Bank owned life insurance 52,984 50,004 Other expense: Professional services 268,060 267,540 324,460 Amortization of capitalized servicing rights 49,906 68,410

International activities

International activities	12 Months Ended
	Dec. 31, 2016
International Activities [Abstract]
International Activities	17. International activities The Company engages in limited international activities including certain trust-related services in Europe, collecting Eurodollar deposits, engaging in foreign currency transactions associated with customer activity, providing credit to support the international activities of domestic companies and holding certain loans to foreign borrowers. Assets and revenues associated with international activities represent less than 1% of the Company’s consolidated assets and revenues. International assets included $292 million and $265 million of loans to foreign borrowers at December 31, 2016 and 2015, respectively. Deposits at M&T Bank’s Cayman Islands office were $202 million and $170 million at December 31, 2016 and 2015, respectively. The Company uses such deposits to facilitate customer demand and as an alternative to short-term borrowings when the costs of such deposits seem reasonable. Deposits at M&T Bank’s office in Ontario, Canada were $50 million at December 31, 2016 and $35 million at December 31, 2015. Revenues from providing international trust-related services were approximately $25 million in 2016, $26 million in 2015 and $31 million in 2014.

Derivative financial instrument

Derivative financial instruments	12 Months Ended
	Dec. 31, 2016
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative financial instruments	18. Derivative financial instruments As part of managing interest rate risk, the Company enters into interest rate swap agreements to modify the repricing characteristics of certain portions of the Company’s portfolios of earning assets and interest-bearing liabilities. The Company designates interest rate swap agreements utilized in the management of interest rate risk as either fair value hedges or cash flow hedges. Interest rate swap agreements are generally entered into with counterparties that meet established credit standards and most contain master netting and collateral provisions protecting the at-risk party. Based on adherence to the Company’s credit standards and the presence of the netting and collateral provisions, the Company believes that the credit risk inherent in these contracts was not significant as of December 31, 2016. The net effect of interest rate swap agreements was to increase net interest income by $37 million in 2016, $44 million in 2015 and $45 million in 2014. The average notional amounts of interest rate swap agreements impacting net interest income that were entered into for interest rate risk management purposes were $1.4 billion in each of 2016, 2015 and 2014. Information about interest rate swap agreements entered into for interest rate risk management purposes summarized by type of financial instrument the swap agreements were intended to hedge follows: Notional Average Weighted- Average Rate Estimated Fair Amount Maturity Fixed Variable Value Gain (In thousands) (In years) (In thousands) December 31, 2016 Fair value hedges: Fixed rate long-term borrowings(a) $ 900,000 1.1 3.75 % 2.08 % $ 11,892 December 31, 2015 Fair value hedges: Fixed rate long-term borrowings(a) $ 1,400,000 1.7 4.42 % 1.39 % $ 43,892 (a) Under the terms of these agreements, the Company receives settlement amounts at a fixed rate and pays at a variable rate. The notional amount of interest rate swap agreements entered into for risk management purposes that were outstanding at December 31, 2016 mature as follows: (In thousands) Year ending December 31: 2017 $ 400,000 2018 500,000 $ 900,000 The Company utilizes commitments to sell residential and commercial real estate loans to hedge the exposure to changes in the fair value of real estate loans held for sale. Such commitments have generally been designated as fair value hedges. The Company also utilizes commitments to sell real estate loans to offset the exposure to changes in fair value of certain commitments to originate real estate loans for sale. Derivative financial instruments used for trading account purposes included interest rate contracts, foreign exchange and other option contracts, foreign exchange forward and spot contracts, and financial futures. Interest rate contracts entered into for trading account purposes had notional values of $21.6 billion and $18.4 billion at December 31, 2016 and 2015, respectively. The notional amounts of foreign currency and other option and futures contracts entered into for trading account purposes aggregated $471 million and $1.6 billion at December 31, 2016 and 2015, respectively. Information about the fair values of derivative instruments in the Company’s consolidated balance sheet and consolidated statement of income follows: Asset Derivatives Liability Derivatives Fair Value Fair Value December 31 December 31 2016 2015 2016 2015 (In thousands) Derivatives designated and qualifying as hedging instruments Fair value hedges: Interest rate swap agreements(a) $ 11,892 $ 43,892 $ — $ — Commitments to sell real estate loans(a) 33,189 1,844 1,347 656 45,081 45,736 1,347 656 Derivatives not designated and qualifying as hedging instruments Mortgage-related commitments to originate real estate loans for sale(a) 8,060 10,282 735 403 Commitments to sell real estate loans(a) 5,210 533 399 846 Trading: Interest rate contracts(b) 228,810 203,517 167,737 153,723 Foreign exchange and other option and futures contracts(b) 7,908 8,569 6,639 7,022 249,988 222,901 175,510 161,994 Total derivatives $ 295,069 $ 268,637 $ 176,857 $ 162,650 (a) Asset derivatives are reported in other assets and liability derivatives are reported in other liabilities. (b) Asset derivatives are reported in trading account assets and liability derivatives are reported in other liabilities. Amount of Gain (Loss) Recognized Year Ended December 31, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 Derivative Hedged Item Derivative Hedged Item Derivative Hedged Item (In thousands) Derivatives in fair value hedging relationships Interest rate swap agreements: Fixed rate long-term borrowings(a) $ (32,000 ) 30,906 $ (29,359 ) 28,719 $ (29,624 ) 28,870 Derivatives not designated as hedging instruments Trading: Interest rate contracts(b) $ 14,042 $ 10,755 $ 3,398 Foreign exchange and other option and futures contracts(b) 7,665 9,337 7,670 Total $ 21,707 $ 20,092 $ 11,068 (a) Reported as other revenues from operations. (b) Reported as trading account and foreign exchange gains. The Company also has commitments to sell and commitments to originate residential and commercial real estate loans that are considered derivatives. The Company designates certain of the commitments to sell real estate loans as fair value hedges of real estate loans held for sale. The Company also utilizes commitments to sell real estate loans to offset the exposure to changes in the fair value of certain commitments to originate real estate loans for sale. As a result of these activities, net unrealized pre-tax gains related to hedged loans held for sale, commitments to originate loans for sale and commitments to sell loans were approximately $28 million and $18 million at December 31, 2016 and 2015, respectively. Changes in unrealized gains and losses are included in mortgage banking revenues and, in general, are realized in subsequent periods as the related loans are sold and commitments satisfied. The Company does not offset derivative asset and liability positions in its consolidated financial statements. The Company’s exposure to credit risk by entering into derivative contracts is mitigated through master netting agreements and collateral posting requirements. Master netting agreements covering interest rate and foreign exchange contracts with the same party include a right to set-off that becomes enforceable in the event of default, early termination or under other specific conditions. The aggregate fair value of derivative financial instruments in a liability position, which are subject to enforceable master netting arrangements, was $34 million and $59 million at December 31, 2016 and 2015, respectively. After consideration of such netting arrangements, the net liability positions with counterparties aggregated $30 million and $55 million at December 31, 2016 and 2015, respectively. The Company was required to post collateral relating to those positions of $27 million and $52 million at December 31, 2016 and 2015, respectively. Certain of the Company’s derivative financial instruments contain provisions that require the Company to maintain specific credit ratings from credit rating agencies to avoid higher collateral posting requirements. If the Company’s debt ratings were to fall below specified ratings, the counterparties to the derivative financial instruments could demand immediate incremental collateralization on those instruments in a net liability position. The aggregate fair value of all derivative financial instruments with such credit risk-related contingent features in a net liability position on December 31, 2016 was $2 million, for which the Company was not required to post collateral in the normal course of business. If the credit risk-related contingent features had been triggered on December 31, 2016, the maximum amount of additional collateral the Company would have been required to post with counterparties was $2 million. The aggregate fair value of derivative financial instruments in an asset position, which are subject to enforceable master netting arrangements, was $15 million and $23 million at December 31, 2016 and 2015, respectively. After consideration of such netting arrangements, the net asset positions with counterparties aggregated $11 million and $19 million at December 31, 2016 and 2015, respectively. Counterparties posted collateral relating to those positions of $9 million and $22 million at December 31, 2016 and 2015, respectively. Trading account interest rate swap agreements entered into with customers are subject to the Company’s credit risk standards and often contain collateral provisions. In addition to the derivative contracts noted above, the Company clears certain derivative transactions through a clearinghouse, rather than directly with counterparties. Those transactions cleared through a clearinghouse require initial margin collateral and additional collateral depending on the contracts being in a net asset or liability position. The amount of initial margin posted by the Company was $111 million and $52 million at December 31, 2016 and 2015, respectively. The net fair values of derivative instruments cleared through clearinghouses for which variation margin is required was a net asset position of $63 million at December 31, 2016. Collateral posted by the clearinghouses associated with that net asset position was $81 million at December 31, 2016. The net fair values of derivative instruments cleared through clearinghouses for which variation margin is required was a net liability position of $50 million at December 31, 2015. Collateral posted by the Company associated with that net liability position was $47 million at December 31, 2015.

Variable interest entities and

Variable interest entities and asset securitizations	12 Months Ended
	Dec. 31, 2016
Text Block [Abstract]
Variable interest entities and asset securitizations	19. Variable interest entities and asset securitizations In accordance with GAAP, the Company determined that it was the primary beneficiary of a residential mortgage loan securitization trust considering its role as servicer and its retained subordinated interests in the trust. As a result, the Company had included the one-to-four family residential mortgage loans that were included in the trust in its consolidated financial statements. In the first quarter of 2016, the securitization trust was terminated as the Company exercised its right to purchase the underlying mortgage loans pursuant to the clean-up call provisions of the trust. At December 31, 2015, the carrying value of the loans in the securitization trust was $81 million. The outstanding principal amount of mortgage-backed securities issued by the qualified special purpose trust that was held by parties unrelated to M&T at December 31, 2015 was $13 million. During the years ended December 31, 2016, 2015 and 2014, the Company securitized one-to-four family residential real estate loans that had been originated for sale in guaranteed mortgage securitizations with Ginnie Mae totaling $24 million, $65 million and $135 million, respectively, and retained those securities in its investment securities portfolio. Pre-tax gains on such transactions were not material. As a result of the securitization structures, the Company does not have effective control over the underlying loans and expects no material credit-related losses on the retained securities as a result of the guarantees by Ginnie Mae. As described in note 9, M&T has issued junior subordinated debentures payable to various trusts that have issued Capital Securities. M&T owns the common securities of those trust entities. The Company is not considered to be the primary beneficiary of those entities and, accordingly, the trusts are not included in the Company’s consolidated financial statements. At December 31, 2016 and 2015, the Company included the junior subordinated debentures as “long-term borrowings” in its consolidated balance sheet and recognized $24 million in other assets for its “investment” in the common securities of the trusts that will be concomitantly repaid to M&T by the respective trust from the proceeds of M&T’s repayment of the junior subordinated debentures associated with preferred capital securities described in note 9. The Company has invested as a limited partner in various partnerships that collectively had total assets of approximately $1.0 billion at December 31, 2016 and $1.1 billion at December 31, 2015. Those partnerships generally construct or acquire properties for which the investing partners are eligible to receive certain federal income tax credits in accordance with government guidelines. Such investments may also provide tax deductible losses to the partners. The partnership investments also assist the Company in achieving its community reinvestment initiatives. As a limited partner, there is no recourse to the Company by creditors of the partnerships. However, the tax credits that result from the Company’s investments in such partnerships are generally subject to recapture should a partnership fail to comply with the respective government regulations. The Company’s maximum exposure to loss of its investments in such partnerships was $294 million, including $102 million of unfunded commitments, at December 31, 2016 and $295 million, including $78 million of unfunded commitments, at December 31, 2015. Contingent commitments to provide additional capital contributions to these partnerships were not material at December 31, 2016. The Company has not provided financial or other support to the partnerships that was not contractually required. Management currently estimates that no material losses are probable as a result of the Company’s involvement with such entities. The Company, in its position as limited partner, does not direct the activities that most significantly impact the economic performance of the partnerships and, therefore, in accordance with the accounting provisions for variable interest entities, the partnership entities are not included in the Company’s consolidated financial statements. The Company’s investment cost is amortized to income taxes in the consolidated statement of income as tax credits and other tax benefits resulting from deductible losses associated with the projects are received. The Company serves as investment advisor for certain registered money-market funds. The Company has no explicit arrangement to provide support to those funds, but may waive portions of its allowable management fees as a result of market conditions.

Fair value measurements

Fair value measurements	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair value measurements	20. Fair value measurements GAAP permits an entity to choose to measure eligible financial instruments and other items at fair value. The Company has not made any fair value elections at December 31, 2016. Pursuant to GAAP, fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. A three-level hierarchy exists in GAAP for fair value measurements based upon the inputs to the valuation of an asset or liability. • Level 1 — Valuation is based on quoted prices in active markets for identical assets and liabilities. • Level 2 — Valuation is determined from quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar instruments in markets that are not active or by model-based techniques in which all significant inputs are observable in the market. • Level 3 — Valuation is derived from model-based and other techniques in which at least one significant input is unobservable and which may be based on the Company’s own estimates about the assumptions that market participants would use to value the asset or liability. When available, the Company attempts to use quoted market prices in active markets to determine fair value and classifies such items as Level 1 or Level 2. If quoted market prices in active markets are not available, fair value is often determined using model-based techniques incorporating various assumptions including interest rates, prepayment speeds and credit losses. Assets and liabilities valued using model-based techniques are classified as either Level 2 or Level 3, depending on the lowest level classification of an input that is considered significant to the overall valuation. The following is a description of the valuation methodologies used for the Company’s assets and liabilities that are measured on a recurring basis at estimated fair value. Trading account assets and liabilities Trading account assets and liabilities consist primarily of interest rate swap agreements and foreign exchange contracts with customers who require such services with offsetting positions with third parties to minimize the Company’s risk with respect to such transactions. The Company generally determines the fair value of its derivative trading account assets and liabilities using externally developed pricing models based on market observable inputs and, therefore, classifies such valuations as Level 2. Mutual funds held in connection with deferred compensation and other arrangements have been classified as Level 1 valuations. Valuations of investments in municipal and other bonds can generally be obtained through reference to quoted prices in less active markets for the same or similar securities or through model-based techniques in which all significant inputs are observable and, therefore, such valuations have been classified as Level 2. Investment securities available for sale The majority of the Company’s available-for-sale investment securities have been valued by reference to prices for similar securities or through model-based techniques in which all significant inputs are observable and, therefore, such valuations have been classified as Level 2. Certain investments in mutual funds and equity securities are actively traded and, therefore, have been classified as Level 1 valuations. Included in collateralized debt obligations at December 31, 2015 were securities backed by trust preferred securities issued by financial institutions and other entities. As disclosed in note 3, the Company sold its collateralized debt obligations in 2016. The Company performed internal modeling to estimate the cash flows and fair value of its portfolio of securities backed by trust preferred securities at December 31, 2015. The modeling techniques included estimating cash flows using bond-specific assumptions about future collateral defaults and related loss severities. The resulting cash flows were then discounted by reference to market yields observed in the single-name trust preferred securities market. In determining a market yield applicable to the estimated cash flows, a margin over LIBOR, ranging from 4% to 10% with a weighted-average of 8% was used. Significant unobservable inputs used in the determination of estimated fair value of collateralized debt obligations are included in the accompanying table of significant unobservable inputs to Level 3 measurements. At December 31, 2015, the total amortized cost and fair value of securities backed by trust preferred securities issued by financial institutions and other entities were $28 million and $47 million, respectively. Real estate loans held for sale The Company utilizes commitments to sell real estate loans to hedge the exposure to changes in fair value of real estate loans held for sale. The carrying value of hedged real estate loans held for sale includes changes in estimated fair value during the hedge period. Typically, the Company attempts to hedge real estate loans held for sale from the date of close through the sale date. The fair value of hedged real estate loans held for sale is generally calculated by reference to quoted prices in secondary markets for commitments to sell real estate loans with similar characteristics and, accordingly, such loans have been classified as a Level 2 valuation. Commitments to originate real estate loans for sale and commitments to sell real estate loans The Company enters into various commitments to originate real estate loans for sale and commitments to sell real estate loans. Such commitments are considered to be derivative financial instruments and, therefore, are carried at estimated fair value on the consolidated balance sheet. The estimated fair values of such commitments were generally calculated by reference to quoted prices in secondary markets for commitments to sell real estate loans to certain government-sponsored entities and other parties. The fair valuations of commitments to sell real estate loans generally result in a Level 2 classification. The estimated fair value of commitments to originate real estate loans for sale are adjusted to reflect the Company’s anticipated commitment expirations. The estimated commitment expirations are considered significant unobservable inputs contributing to the Level 3 classification of commitments to originate real estate loans for sale. Significant unobservable inputs used in the determination of estimated fair value of commitments to originate real estate loans for sale are included in the accompanying table of significant unobservable inputs to Level 3 measurements. Interest rate swap agreements used for interest rate risk management The Company utilizes interest rate swap agreements as part of the management of interest rate risk to modify the repricing characteristics of certain portions of its portfolios of earning assets and interest-bearing liabilities. The Company generally determines the fair value of its interest rate swap agreements using externally developed pricing models based on market observable inputs and, therefore, classifies such valuations as Level 2. The Company has considered counterparty credit risk in the valuation of its interest rate swap agreement assets and has considered its own credit risk in the valuation of its interest rate swap agreement liabilities . The following tables present assets and liabilities at December 31, 2016 and 2015 measured at estimated fair value on a recurring basis: Fair Value Measurements at December 31, 2016 Level 1 (a) Level 2 (a) Level 3 (In thousands) Trading account assets $ 323,867 $ 46,135 $ 277,732 $ — Investment securities available for sale: U.S. Treasury and federal agencies 1,902,544 — 1,902,544 — Obligations of states and political subdivisions 3,641 — 3,641 — Mortgage-backed securities: Government issued or guaranteed 10,954,861 — 10,954,861 — Privately issued 44 — — 44 Other debt securities 118,516 — 118,516 — Equity securities 352,466 301,711 50,755 — 13,332,072 301,711 13,030,317 44 Real estate loans held for sale 1,056,180 — 1,056,180 — Other assets(b) 58,351 — 50,291 8,060 Total assets $ 14,770,470 $ 347,846 $ 14,414,520 $ 8,104 Trading account liabilities $ 174,376 $ — $ 174,376 $ — Other liabilities(b) 2,481 — 1,746 735 Total liabilities $ 176,857 $ — $ 176,122 $ 735 Fair Value Measurements at December 31, 2015 Level 1(a) Level 2(a) Level 3 (In thousands) Trading account assets $ 273,783 $ 56,763 $ 217,020 $ — Investment securities available for sale: U.S. Treasury and federal agencies 299,997 — 299,997 — Obligations of states and political subdivisions 6,028 — 6,028 — Mortgage-backed securities: Government issued or guaranteed 11,686,628 — 11,686,628 — Privately issued 74 — — 74 Collateralized debt obligations 47,393 — — 47,393 Other debt securities 118,880 — 118,880 — Equity securities 83,671 65,178 18,493 — 12,242,671 65,178 12,130,026 47,467 Real estate loans held for sale 392,036 — 392,036 — Other assets(b) 56,551 — 46,269 10,282 Total assets $ 12,965,041 $ 121,941 $ 12,785,351 $ 57,749 Trading account liabilities $ 160,745 $ — $ 160,745 $ — Other liabilities(b) 1,905 — 1,502 403 Total liabilities $ 162,650 $ — $ 162,247 $ 403 (a) There were no significant transfers between Level 1 and Level 2 of the fair value hierarchy during the years ended December 31, 2016 and 2015. (b) Comprised predominantly of interest rate swap agreements used for interest rate risk management (Level 2), commitments to sell real estate loans (Level 2) and commitments to originate real estate loans to be held for sale (Level 3). The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the year ended December 31, 2016 were as follows: Investment Securities Available for S Privately Issued Mortgage-Backed Securities Collateralized Debt Obligations Other Assets and Other Liabilities (In thousands) Balance - January 1, 2016 $ 74 $ 47,393 $ 9,879 Total gains (losses) realized/unrealized: Included in earnings — 30,041 (c) 110,937 (b) Included in other comprehensive income — (18,268 ) (d) — Sales — (58,296 ) — Settlements (30 ) (870 ) — Transfers out of Level 3(a) — — (113,491 ) (e) Balance — December 31, 2016 $ 44 $ — $ 7,325 Changes in unrealized gains included in earnings related to assets still held at December 31, 2016 $ — $ — $ 7,256 (b) The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the year ended December 31, 2015 were as follows: Investment Securities Available for S Privately Issued Mortgage-Backed Securities Collateralized Debt Obligations Other Assets and Other Liabilities (In thousands) Balance — January 1, 2015 $ 103 $ 50,316 $ 17,347 Total gains realized/unrealized: Included in earnings — — 87,061 (b) Included in other comprehensive income — 3,254 (d) — Settlements (29 ) (6,177 ) — Transfers out of Level 3(a) — — (94,529 ) (e) Balance — December 31, 2015 $ 74 $ 47,393 $ 9,879 Changes in unrealized gains included in earnings related to assets still held at December 31, 2015 $ — $ — $ 8,850 (b) The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the year ended December 31, 2014 were as follows: Investment Securities Available for S Privately Issued Mortgage-Backed Securities Collateralized Debt Obligations Other Assets and Other Liabilities (In thousands) Balance – January 1, 2014 $ 1,850 $ 63,083 $ 3,941 Total gains realized/unrealized: Included in earnings — — 83,417 (b) Included in other comprehensive income 271 (d) 8,209 (d) — Settlements (2,018 ) (20,976 ) — Transfers out of Level 3(a) — — (70,011 ) (e) Balance – December 31, 2014 $ 103 $ 50,316 $ 17,347 Changes in unrealized gains included in earnings related to assets still held at December 31, 2014 $ — $ — $ 18,196 (b) (a ) The Company’s policy for transfers between fair value levels is to recognize the transfer as of the actual date of the event or change in circumstances that caused the transfer. (b) Reported as mortgage banking revenues in the consolidated statement of income and includes the fair value of commitment issuances and expirations. (c) Reported as gain (loss) on bank investment securities in the consolidated statement of income. (d) Reported as net unrealized gains (losses) on investment securities in the consolidated statement of comprehensive income. (e) Transfers out of Level 3 consist of interest rate locks transferred to closed loans. The Company is required, on a nonrecurring basis, to adjust the carrying value of certain assets or provide valuation allowances related to certain assets using fair value measurements. The more significant of those assets follow. Loans Loans are generally not recorded at fair value on a recurring basis. Periodically, the Company records nonrecurring adjustments to the carrying value of loans based on fair value measurements for partial charge-offs of the uncollectible portions of those loans. Nonrecurring adjustments also include certain impairment amounts for collateral-dependent loans when establishing the allowance for credit losses. Such amounts are generally based on the fair value of the underlying collateral supporting the loan and, as a result, the carrying value of the loan less the calculated valuation amount does not necessarily represent the fair value of the loan. Real estate collateral is typically valued using appraisals or other indications of value based on recent comparable sales of similar properties or assumptions generally observable in the marketplace and the related nonrecurring fair value measurement adjustments have generally been classified as Level 2, unless significant adjustments have been made to the valuation that are not readily observable by market participants. Non-real estate collateral supporting commercial loans generally consists of business assets such as receivables, inventory and equipment. Fair value estimations are typically determined by discounting recorded values of those assets to reflect estimated net realizable value considering specific borrower facts and circumstances and the experience of credit personnel in their dealings with similar borrower collateral liquidations. Such discounts were generally in the range of 15% to 90% at December 31, 2016. As these discounts are not readily observable and are considered significant, the valuations have been classified as Level 3. Automobile collateral is typically valued by reference to independent pricing sources based on recent sales transactions of similar vehicles, and the related non-recurring fair value measurement adjustments have been classified as Level 2. Collateral values for other consumer installment loans are generally estimated based on historical recovery rates for similar types of loans. As these recovery rates are not readily observable by market participants, such valuation adjustments have been classified as Level 3. Loans subject to nonrecurring fair value measurement were $293 million at December 31, 2016, ($153 million and $140 million of which were classified as Level 2 and Level 3, respectively), $210 million at December 31, 2015 ($106 million and $104 million of which were classified as Level 2 and Level 3, respectively), and $173 million at December 31, 2014 ($94 million and $79 million of which were classified as Level 2 and Level 3, respectively). Changes in fair value recognized during the years ended December 31, 2016, 2015 and 2014 for partial charge-offs of loans and loan impairment reserves on loans held by the Company at the end of each of those years were decreases of $71 million, $75 million and $55 million, respectively. Assets taken in foreclosure of defaulted loans Assets taken in foreclosure of defaulted loans are primarily comprised of commercial and residential real property and are generally measured at the lower of cost or fair value less costs to sell. The fair value of the real property is generally determined using appraisals or other indications of value based on recent comparable sales of similar properties or assumptions generally observable in the marketplace, and the related nonrecurring fair value measurement adjustments have generally been classified as Level 2. Assets taken in foreclosure of defaulted loans subject to nonrecurring fair value measurement were $56 million and $29 million at December 31, 2016 and December 31, 2015, respectively. Changes in fair value recognized during the years ended December 31, 2016, 2015 and 2014 for foreclosed assets held by the Company at the end of each of those years were not material. Significant unobservable inputs to level 3 measurements The following tables present quantitative information about significant unobservable inputs used in the fair value measurements for Level 3 assets and liabilities at December 31, 2016 and 2015: Fair Value at December 31, 2016 Valuation Technique Unobservable Inputs/Assumptions Range (Weighted- Average) (In thousands) Recurring fair value measurements: Privately issued mortgage-backed securities $ 44 Two independent pricing quotes — — Net other assets (liabilities)(a) 7,325 Discounted cash flow Commitment expirations 0%-77% (30%) Fair Value at December 31, 2015 Valuation Technique Unobservable Inputs/Assumptions Range (Weighted- Average) (In thousands) Recurring fair value measurements: Privately issued mortgage-backed securities $ 74 Two independent pricing quotes — — Collateralized debt obligations 47,393 Discounted cash flow Probability of default 10%-56% (31%) Loss severity 100% Net other assets (liabilities)(a) 9,879 Discounted cash flow Commitment expirations 0%-60% (39%) (a) Other Level 3 assets (liabilities) consist of commitments to originate real estate loans. Sensitivity of fair value measurements to changes in unobservable inputs An increase (decrease) in the estimate of expirations for commitments to originate real estate loans would generally result in a lower (higher) fair value measurement. Estimated commitment expirations are derived considering loan type, changes in interest rates and remaining length of time until closing. An increase (decrease) in the probability of default and loss severity for collateralized debt securities would generally result in a lower (higher) fair value measurement. Disclosures of fair value of financial instruments The carrying amounts and estimated fair value for financial instrument assets (liabilities) are presented in the following table: December 31, 2016 Carrying Amount Estimated Fair Value Level 1 Level 2 Level 3 (In thousands) Financial assets: Cash and cash equivalents $ 1,320,549 1,320,549 1,249,654 70,895 — Interest-bearing deposits at banks 5,000,638 5,000,638 — 5,000,638 — Trading account assets 323,867 323,867 46,135 277,732 — Investment securities 16,250,468 16,244,412 301,711 15,821,176 121,525 Loans and leases: Commercial loans and leases 22,610,047 22,239,428 — — 22,239,428 Commercial real estate loans 33,506,394 33,129,428 — 642,590 32,486,838 Residential real estate loans 22,590,912 22,638,167 — 4,912,488 17,725,679 Consumer loans 12,146,063 12,061,590 — — 12,061,590 Allowance for credit losses (988,997 ) — — — — Loans and leases, net 89,864,419 90,068,613 — 5,555,078 84,513,535 Accrued interest receivable 308,805 308,805 — 308,805 — Financial liabilities: Noninterest-bearing deposits $ (32,813,896 ) (32,813,896 ) — (32,813,896 ) — Savings and interest-checking deposits (52,346,207 ) (52,346,207 ) — (52,346,207 ) — Time deposits (10,131,846 ) (10,222,585 ) — (10,222,585 ) — Deposits at Cayman Islands office (201,927 ) (201,927 ) — (201,927 ) — Short-term borrowings (163,442 ) (163,442 ) — (163,442 ) — Long-term borrowings (9,493,835 ) (9,473,844 ) — (9,473,844 ) — Accrued interest payable (75,172 ) (75,172 ) — (75,172 ) — Trading account liabilities (174,376 ) (174,376 ) — (174,376 ) — Other financial instruments: Commitments to originate real estate loans for sale $ 7,325 7,325 — — 7,325 Commitments to sell real estate loans 36,653 36,653 — 36,653 — Other credit-related commitments (136,295 ) (136,295 ) — — (136,295 ) Interest rate swap agreements used for interest rate risk management 11,892 11,892 — 11,892 — December 31, 2015 Carrying Amount Estimated Fair Value Level 1 Level 2 Level 3 (In thousands) Financial assets: Cash and cash equivalents $ 1,368,040 1,368,040 1,276,678 91,362 — Interest-bearing deposits at banks 7,594,350 7,594,350 — 7,594,350 — Trading account assets 273,783 273,783 56,763 217,020 — Investment securities 15,656,439 15,660,877 65,178 15,406,404 189,295 Loans and leases: Commercial loans and leases 20,422,338 20,146,201 — — 20,146,201 Commercial real estate loans 29,197,311 29,044,244 — 38,774 29,005,470 Residential real estate loans 26,270,103 26,267,771 — 4,727,816 21,539,955 Consumer loans 11,599,747 11,550,270 — — 11,550,270 Allowance for credit losses (955,992 ) — — — — Loans and leases, net 86,533,507 87,008,486 — 4,766,590 82,241,896 Accrued interest receivable 306,496 306,496 — 306,496 — Financial liabilities: Noninterest-bearing deposits $ (29,110,635 ) (29,110,635 ) — (29,110,635 ) — Savings and interest-checking deposits (49,566,644 ) (49,566,644 ) — (49,566,644 ) — Time deposits (13,110,392 ) (13,135,042 ) — (13,135,042 ) — Deposits at Cayman Islands office (170,170 ) (170,170 ) — (170,170 ) — Short-term borrowings (2,132,182 ) (2,132,182 ) — (2,132,182 ) — Long-term borrowings (10,653,858 ) (10,639,556 ) — (10,639,556 ) — Accrued interest payable (85,145 ) (85,145 ) — (85,145 ) — Trading account liabilities (160,745 ) (160,745 ) — (160,745 ) — Other financial instruments: Commitments to originate real estate loans for sale $ 9,879 9,879 — — 9,879 Commitments to sell real estate loans 875 875 — 875 — Other credit-related commitments (122,334 ) (122,334 ) — — (122,334 ) Interest rate swap agreements used for interest rate risk management 43,892 43,892 — 43,892 — With the exception of marketable securities, certain off-balance sheet financial instruments and mortgage loans originated for sale, the Company’s financial instruments are not readily marketable and market prices do not exist. The Company, in attempting to comply with the provisions of GAAP that require disclosures of fair value of financial instruments, has not attempted to market its financial instruments to potential buyers, if any exist. Since negotiated prices in illiquid markets depend greatly upon the then present motivations of the buyer and seller, it is reasonable to assume that actual sales prices could vary widely from any estimate of fair value made without the benefit of negotiations. Additionally, changes in market interest rates can dramatically impact the value of financial instruments in a short period of time. The following assumptions, methods and calculations were used in determining the estimated fair value of financial instruments not measured at fair value in the consolidated balance sheet. Cash and cash equivalents, interest-bearing deposits at banks, deposits at Cayman Islands office, short-term borrowings, accrued interest receivable and accrued interest payable Due to the nature of cash and cash equivalents and the near maturity of interest-bearing deposits at banks, deposits at Cayman Islands office, short-term borrowings, accrued interest receivable and accrued interest payable, the Company estimated that the carrying amount of such instruments approximated estimated fair value. Investment securities Estimated fair values of investments in readily marketable securities were generally based on quoted market prices. Investment securities that were not readily marketable were assigned amounts based on estimates provided by outside parties or modeling techniques that relied upon discounted calculations of projected cash flows or, in the case of other investment securities, which include capital stock of the Federal Reserve Bank of New York and the Federal Home Loan Bank of New York, at an amount equal to the carrying amount. Loans and leases In general, discount rates used to calculate values for loan products were based on the Company’s pricing at the respective period end. A higher discount rate was assumed with respect to estimated cash flows associated with nonaccrual loans. Projected loan cash flows were adjusted for estimated credit losses. However, such estimates made by the Company may not be indicative of assumptions and adjustments that a purchaser of the Company’s loans and leases would seek. Deposits Pursuant to GAAP, the estimated fair value ascribed to noninterest-bearing deposits, savings deposits and interest-checking deposits must be established at carrying value because of the customers’ ability to withdraw funds immediately. Time deposit accounts are required to be revalued based upon prevailing market interest rates for similar maturity instruments. As a result, amounts assigned to time deposits were based on discounted cash flow calculations using prevailing market interest rates based on the Company’s pricing at the respective date for deposits with comparable remaining terms to maturity. The Company believes that deposit accounts have a value greater than that prescribed by GAAP. The Company feels, however, that the value associated with these deposits is greatly influenced by characteristics of the buyer, such as the ability to reduce the costs of servicing the deposits and deposit attrition which often occurs following an acquisition. Long-term borrowings The amounts assigned to long-term borrowings were based on quoted market prices, when available, or were based on discounted cash flow calculations using prevailing market interest rates for borrowings of similar terms and credit risk. Other commitments and contingencies As described in note 21, in the normal course of business, various commitments and contingent liabilities are outstanding, such as loan commitments, credit guarantees and letters of credit. The Company’s pricing of such financial instruments is based largely on credit quality and relationship, probability of funding and other requirements. Loan commitments often have fixed expiration dates and contain termination and other clauses which provide for relief from funding in the event of significant deterioration in the credit quality of the customer. The rates and terms of the Company’s loan commitments, credit guarantees and letters of credit are competitive with other financial institutions operating in markets served by the Company. The Company believes that the carrying amounts, which are included in other liabilities, are reasonable estimates of the fair value of these financial instruments. The Company does not believe that the estimated information presented herein is representative of the earnings power or value of the Company. The preceding analysis, which is inherently limited in depicting fair value, also does not consider any value associated with existing customer relationships nor the ability of the Company to create value through loan origination, deposit gathering or fee generating activities. Many of the estimates presented herein are based upon the use of highly subjective information and assumptions and, accordingly, the results may not be precise. Management believes that fair value estimates may not be comparable between financial institutions due to the wide range of permitted valuation techniques and numerous estimates which must be made. Furthermore, because the disclosed fair value amounts were estimated as of the balance sheet date, the amounts actually realized or paid upon maturity or settlement of the various financial instruments could be significantly different.

Commitments and contingencies

Commitments and contingencies	12 Months Ended
	Dec. 31, 2016
Commitments And Contingencies Disclosure [Abstract]
Commitments and contingencies	21. Commitments and contingencies In the normal course of business, various commitments and contingent liabilities are outstanding. The following table presents the Company’s significant commitments. Certain of these commitments are not included in the Company’s consolidated balance sheet. December 31 2016 2015 (In thousands) Commitments to extend credit Home equity lines of credit $ 5,499,609 $ 5,631,680 Commercial real estate loans to be sold 70,100 57,597 Other commercial real estate 6,451,709 5,949,933 Residential real estate loans to be sold 478,950 488,621 Other residential real estate 232,721 212,619 Commercial and other 12,298,473 11,802,850 Standby letters of credit 2,987,091 3,330,013 Commercial letters of credit 44,723 55,559 Financial guarantees and indemnification contracts 3,043,580 2,794,322 Commitments to sell real estate loans 1,489,237 782,885 Commitments to extend credit are agreements to lend to customers, generally having fixed expiration dates or other termination clauses that may require payment of a fee. Standby and commercial letters of credit are conditional commitments issued to guarantee the performance of a customer to a third party. Standby letters of credit generally are contingent upon the failure of the customer to perform according to the terms of the underlying contract with the third party, whereas commercial letters of credit are issued to facilitate commerce and typically result in the commitment being funded when the underlying transaction is consummated between the customer and a third party. The credit risk associated with commitments to extend credit and standby and commercial letters of credit is essentially the same as that involved with extending loans to customers and is subject to normal credit policies. Collateral may be obtained based on management’s assessment of the customer’s creditworthiness. Financial guarantees and indemnification contracts are oftentimes similar to standby letters of credit and include mandatory purchase agreements issued to ensure that customer obligations are fulfilled, recourse obligations associated with sold loans, and other guarantees of customer performance or compliance with designated rules and regulations. Included in financial guarantees and indemnification contracts are loan principal amounts sold with recourse in conjunction with the Company’s involvement in the Fannie Mae DUS program. The Company’s maximum credit risk for recourse associated with loans sold under this program totaled approximately $2.8 billion and $2.5 billion at December 31, 2016 and 2015, respectively. Since many loan commitments, standby letters of credit, and guarantees and indemnification contracts expire without being funded in whole or in part, the contract amounts are not necessarily indicative of future cash flows. The Company utilizes commitments to sell real estate loans to hedge exposure to changes in the fair value of real estate loans held for sale. Such commitments are considered derivatives and along with commitments to originate real estate loans to be held for sale are generally recorded in the consolidated balance sheet at estimated fair market value. The Company occupies certain banking offices and uses certain equipment under noncancelable operating lease agreements expiring at various dates over the next 22 years. Minimum lease payments under noncancelable operating leases are summarized in the following table: (In thousands) Year ending December 31: 2017 $ 99,847 2018 94,448 2019 74,814 2020 58,216 2021 44,508 Later years 94,825 $ 466,658 The Company is contractually obligated to repurchase previously sold residential real estate loans that do not ultimately meet investor sale criteria related to underwriting procedures or loan documentation. When required to do so, the Company may reimburse loan purchasers for losses incurred or may repurchase certain loans. The Company reduces residential mortgage banking revenues by an estimate for losses related to its obligations to loan purchasers. The amount of those charges is based on the volume of loans sold, the level of reimbursement requests received from loan purchasers and estimates of losses that may be associated with previously sold loans. Nevertheless, given the outcome of the matter discussed in the following paragraph, at December 31, 2016 the Company’s remaining obligation to loan purchasers was not considered material to the Company’s consolidated financial position. The Company was the subject of an investigation by government agencies relating to the origination of Federal Housing Administration (“FHA”) insured residential home loans and residential home loans sold to The Federal Home Loan Mortgage Corporation (“Freddie Mac”) and Fannie Mae. A number of other U.S. financial institutions have announced similar investigations. Regarding FHA loans, the U.S. Department of Housing and Urban Development (“HUD”) Office of Inspector General and the U.S. Department of Justice (collectively, the “Government”) investigated whether the Company complied with underwriting guidelines concerning certain loans where HUD paid FHA insurance claims. The Company fully cooperated with the investigation. The Government advised the Company that based upon its review of a sample of loans for which an FHA insurance claim was paid by HUD, some of the loans did not meet underwriting guidelines. The Company, based on its own review of the sample, did not agree with the sampling methodology and loan analysis employed by the Government. Regarding loans originated by the Company and sold to Freddie Mac and Fannie Mae, the investigation concerned whether the mortgages sold to Freddie Mac and Fannie Mae complied with applicable underwriting guidelines. The Company also cooperated with that portion of the investigation. In order to bring those investigations to a close, M&T Bank entered into a settlement agreement with the Government under which M&T Bank paid $64 million on May 12, 2016, without admitting liability. As a result, on May 20, 2016, a Joint Stipulation of Dismissal was filed with the United States District Court for the Western District of New York. The settlement did not have a material impact on the Company’s consolidated financial condition or results of operations in the year ended December 31, 2016. M&T and its subsidiaries are subject in the normal course of business to various pending and threatened legal proceedings and other matters in which claims for monetary damages are asserted. On an on-going basis management, after consultation with legal counsel, assesses the Company’s liabilities and contingencies in connection with such proceedings. For those matters where it is probable that the Company will incur losses and the amounts of the losses can be reasonably estimated, the Company records an expense and corresponding liability in its consolidated financial statements. To the extent the pending or threatened litigation could result in exposure in excess of that liability, the amount of such excess is not currently estimable. Although not considered probable, the range of reasonably possible losses for such matters in the aggregate, beyond the existing recorded liability, was between $0 and $40 million. Although the Company does not believe that the outcome of pending litigations will be material to the Company’s consolidated financial position, it cannot rule out the possibility that such outcomes will be material to the consolidated results of operations for a particular reporting period in the future.

Segment information

Segment information	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Segment information	22. Segment information Reportable segments have been determined based upon the Company’s internal profitability reporting system, which is organized by strategic business unit. Certain strategic business units have been combined for segment information reporting purposes where the nature of the products and services, the type of customer and the distribution of those products and services are similar. The reportable segments are Business Banking, Commercial Banking, Commercial Real Estate, Discretionary Portfolio, Residential Mortgage Banking and Retail Banking. The financial information of the Company’s segments was compiled utilizing the accounting policies described in note 1 with certain exceptions. The more significant of these exceptions are described herein. The Company allocates interest income or interest expense using a methodology that charges users of funds (assets) interest expense and credits providers of funds (liabilities) with income based on the maturity, prepayment and/or repricing characteristics of the assets and liabilities. The net effect of this allocation is recorded in the “All Other” category. A provision for credit losses is allocated to segments in an amount based largely on actual net charge-offs incurred by the segment during the period plus or minus an amount necessary to adjust the segment’s allowance for credit losses due to changes in loan balances. In contrast, the level of the consolidated provision for credit losses is determined using the methodologies described in notes 1 and 5. Indirect fixed and variable expenses incurred by certain centralized support areas are allocated to segments based on actual usage (for example, volume measurements) and other criteria. Certain types of administrative expenses and bankwide expense accruals (including amortization of core deposit and other intangible assets associated with acquisitions of financial institutions) are generally not allocated to segments. Income taxes are allocated to segments based on the Company’s marginal statutory tax rate adjusted for any tax-exempt income or non-deductible expenses. Equity is allocated to the segments based on regulatory capital requirements and in proportion to an assessment of the inherent risks associated with the business of the segment (including interest, credit and operating risk). The management accounting policies and processes utilized in compiling segment financial information are highly subjective and, unlike financial accounting, are not based on authoritative guidance similar to GAAP. As a result, reported segment results are not necessarily comparable with similar information reported by other financial institutions. Furthermore, changes in management structure or allocation methodologies and procedures may result in changes in reported segment financial data. During 2016, the Company revised its funds transfer pricing allocation related to borrowings and to the residential real estate loans obtained in the acquisition of Hudson City, retroactive to 2015. Accordingly, segment financial information for the year ended December 31, 2015 has been reclassified to conform to the current methodology. As a result, net interest income, income tax expense and net income increased in the Discretionary Portfolio segment and decreased in the “All Other” category by $12 million, $5 million and $7 million, respectively, for the year ended December 31, 2015 from that which was previously reported. Information about the Company’s segments is presented in the accompanying table. Income statement amounts are in thousands of dollars. Balance sheet amounts are in millions of dollars. For the Years Ended December 31, 2016, 2015 and 2014 Business Banking Commercial Banking Commercial Real Estate Discretionary Portfolio 2016 2015 2014 2016 2015 2014 2016 2015 2014 2016 2015 2014 Net interest income(a) $ 354,333 $ 338,855 $ 345,773 $ 785,874 $ 753,604 $ 746,344 $ 608,385 $ 577,922 $ 555,358 $ 345,926 $ 97,626 $ 74,204 Noninterest income 108,783 108,195 105,149 274,923 290,142 254,295 179,706 142,948 125,087 26,075 28,114 27,464 463,116 447,050 450,922 1,060,797 1,043,746 1,000,639 788,091 720,870 680,445 372,001 125,740 101,668 Provision for credit losses 12,709 15,513 18,883 34,903 25,089 33,213 (3,447 ) (8,003 ) (7,339 ) 32,925 7,599 16,547 Amortization of core deposit and other intangible assets — — — — — — — — — — — — Depreciation and other amortization 404 407 405 520 566 588 20,120 19,247 16,300 472 679 891 Other noninterest expense 292,124 264,163 263,734 327,616 288,303 284,091 204,965 169,688 169,039 95,300 49,839 33,522 Income (loss) before taxes 157,879 166,967 167,900 697,758 729,788 682,747 566,453 539,938 502,445 243,304 67,623 50,708 Income tax expense (benefit) 64,533 68,209 68,630 286,062 298,758 279,819 216,095 199,297 186,485 79,766 8,351 2,365 Net income (loss) $ 93,346 $ 98,758 $ 99,270 $ 411,696 $ 431,030 $ 402,928 $ 350,358 $ 340,641 $ 315,960 $ 163,538 $ 59,272 $ 48,343 Average total assets (in millions) $ 5,456 $ 5,339 $ 5,278 $ 25,592 $ 24,143 $ 22,860 $ 21,131 $ 18,827 $ 17,405 $ 40,867 $ 26,648 $ 20,798 Capital expenditures (in millions) $ — $ — $ 2 $ — $ — $ — $ — $ — $ — $ — $ — $ — For the Years Ended December 31, 2016, 2015 and 2014 Residential Mortgage Banking Retail Banking All Other Total 2016 2015 2014 2016 2015 2014 2016 2015 2014 2016 2015 2014 Net interest income(a) $ 70,655 $ 63,939 $ 67,482 $ 1,074,125 $ 917,041 $ 908,828 $ 230,589 $ 93,600 $ (21,543 ) $ 3,469,887 $ 2,842,587 $ 2,676,446 Noninterest income 342,858 336,099 331,366 323,176 324,953 336,042 570,475 594,586 599,870 1,825,996 1,825,037 1,779,273 413,513 400,038 398,848 1,397,301 1,241,994 1,244,870 801,064 688,186 578,327 5,295,883 4,667,624 4,455,719 Provision for credit losses (3,617 ) (5,225 ) (1,508 ) 120,437 72,953 77,158 (3,910 ) 62,074 (12,954 ) 190,000 170,000 124,000 Amortization of core deposit and other intangible assets — — — — — — 42,613 26,424 33,824 42,613 26,424 33,824 Depreciation and other amortization 30,264 27,883 47,086 37,657 35,291 37,788 68,541 64,852 61,848 157,978 148,925 164,906 Other noninterest expense 258,141 233,651 216,556 776,123 682,594 668,919 892,625 959,345 854,883 2,846,894 2,647,583 2,490,744 Income (loss) before taxes 128,725 143,729 136,714 463,084 451,156 461,005 (198,805 ) (424,509 ) (359,274 ) 2,058,398 1,674,692 1,642,245 Income tax expense (benefit) 49,047 55,151 52,172 188,438 183,638 187,647 (140,657 ) (218,379 ) (201,119 ) 743,284 595,025 575,999 Net income (loss) $ 79,678 $ 88,578 $ 84,542 $ 274,646 $ 267,518 $ 273,358 $ (58,148 ) $ (206,130 ) $ (158,155 ) $ 1,315,114 $ 1,079,667 $ 1,066,246 Average total assets (in millions) $ 2,569 $ 2,918 $ 3,076 $ 11,840 $ 11,035 $ 10,449 $ 16,885 $ 12,870 $ 12,277 $ 124,340 $ 101,780 $ 92,143 Capital expenditures (in millions) $ — $ — $ — $ 46 $ 14 $ 14 $ 62 $ 68 $ 57 $ 108 $ 82 $ 73 (a) Net interest income is the difference between actual taxable-equivalent interest earned on assets and interest paid on liabilities by a segment and a funding charge (credit) based on the Company’s internal funds transfer pricing methodology. Segments are charged a cost to fund any assets (e.g. loans) and are paid a funding credit for any funds provided (e.g. deposits). The taxable-equivalent adjustment aggregated $26,962,000 in 2016, $24,463,000 in 2015 and $23,642,000 in 2014 and is eliminated in “All Other” net interest income and income tax expense (benefit). The Business Banking segment provides deposit, lending, cash management and other financial services to small businesses and professionals through the Company’s banking office network and several other delivery channels, including business banking centers, telephone banking, Internet banking and automated teller machines. The Commercial Banking segment provides a wide range of credit products and banking services to middle-market and large commercial customers, mainly within the markets the Company serves. Among the services provided by this segment are commercial lending and leasing, letters of credit, deposit products and cash management services. The Commercial Real Estate segment provides credit services which are secured by various types of multifamily residential and commercial real estate and deposit services to its customers. Activities of this segment include the origination, sales and servicing of commercial real estate loans. Commercial real estate loans held for sale are included in the Commercial Real Estate Segment. The Discretionary Portfolio segment includes securities; residential real estate loans and other assets; short-term and long-term borrowed funds; brokered deposits; and Cayman Islands branch deposits. This segment also provides foreign exchange services to customers. Residential real estate loans obtained in the Hudson City acquisition on November 1, 2015 are included in this segment. The Residential Mortgage Banking segment originates and services residential real estate loans for consumers and sells substantially all of those loans in the secondary market to investors or to the Discretionary Portfolio segment. The segment periodically purchases servicing rights to loans that have been originated by other entities. Residential real estate loans held for sale are included in the Residential Mortgage Banking segment. The Retail Banking segment offers a variety of services to consumers through several delivery channels that include banking offices, automated teller machines, and telephone, mobile and Internet banking. Consumer loans and deposits obtained in the acquisition of Hudson City have been included in this segment. The “All Other” category includes other operating activities of the Company that are not directly attributable to the reported segments; the difference between the provision for credit losses and the calculated provision allocated to the reportable segments; goodwill and core deposit and other intangible assets resulting from acquisitions of financial institutions; merger-related gains and expenses resulting from acquisitions; the net impact of the Company’s internal funds transfer pricing methodology; eliminations of transactions between reportable segments; certain nonrecurring transactions; the residual effects of unallocated support systems and general and administrative expenses; and the impact of interest rate risk management strategies. The amount of intersegment activity eliminated in arriving at consolidated totals was included in the “All Other” category as follows: Year Ended December 31 2016 2015 2014 (In thousands) Revenues $ (48,625 ) $ (48,972 ) $ (49,800 ) Expenses (40,422 ) (13,332 ) (12,014 ) Income taxes (benefit) (3,338 ) (14,503 ) (15,375 ) Net income (loss) (4,865 ) (21,137 ) (22,411 ) The Company conducts substantially all of its operations in the United States. There are no transactions with a single customer that in the aggregate result in revenues that exceed ten percent of consolidated total revenues.

Regulatory matters

Regulatory matters	12 Months Ended
	Dec. 31, 2016
Banking And Thrift [Abstract]
Regulatory matters	23. Regulatory matters Payment of dividends by M&T’s banking subsidiaries is restricted by various legal and regulatory limitations. Dividends from any banking subsidiary to M&T are limited by the amount of earnings of the banking subsidiary in the current year and the preceding two years. For purposes of this test, at December 31, 2016, approximately $627 million was available for payment of dividends to M&T from banking subsidiaries. Additionally, the Federal Reserve Board requires bank holding companies with $50 billion or more of total consolidated assets to submit annual capital plans. Such bank holding companies may pay dividends and repurchase stock only in accordance with a capital plan that the Federal Reserve Board has not objected to. Banking regulations prohibit extensions of credit by the subsidiary banks to M&T unless appropriately secured by assets. Securities of affiliates are not eligible as collateral for this purpose. The bank subsidiaries are required to maintain reserves against certain deposit liabilities. During the maintenance periods that included December 31, 2016 and 2015, cash and due from banks and interest-earning deposits at banks included a daily average of $594,831,000 and $664,586,000, respectively, for such purpose. M&T and its subsidiary banks are required to comply with applicable capital adequacy regulations established by the federal banking agencies. Failure to meet minimum capital requirements can result in certain mandatory, and possibly additional discretionary, actions by regulators that, if undertaken, could have a material effect on the Company’s financial statements. Pursuant to the rules in effect as of December 31, 2016, the required minimum and well capitalized capital ratios are as follows: Well Minimum Capitalized ● Common equity Tier 1 ("CET1") to risk-weighted assets 4.5 % 6.5 % ● Tier 1 capital to risk-weighted assets 6.0 % 8.0 % ● Total capital to risk-weighted assets 8.0 % 10.0 % ● Leverage — Tier 1 capital to average total assets, as defined 4.0 % 5.0 % In addition, capital regulations provide for the phase-in of a “capital conservation buffer” composed entirely of CET1 on top of these minimum risk-weighted asset ratios. When fully phased-in on January 1, 2019 the capital conservation buffer will be 2.5%. For 2016, the phase-in transition portion of that buffer was .625%. The capital ratios and amounts of the Company and its banking subsidiaries as of December 31, 2016 and 2015 are presented below: M&T (Consolidated) M&T Bank Wilmington Trust, N.A. (Dollars in thousands) December 31, 2016: Common equity Tier 1 capital Amount $ 10,849,642 $ 10,115,688 $ 496,801 Ratio(a) 10.70 % 10.02 % 57.08 % Minimum required amount(b) 5,195,288 5,175,310 44,607 Tier 1 capital Amount 12,083,948 10,115,688 496,801 Ratio(a) 11.92 % 10.02 % 57.08 % Minimum required amount(b) 6,715,859 6,690,035 57,662 Total capital Amount 14,282,492 11,812,114 501,111 Ratio(a) 14.09 % 11.70 % 57.57 % Minimum required amount(b) 8,743,289 8,709,668 75,070 Leverage Amount 12,083,948 10,115,688 496,801 Ratio(c) 9.99 % 8.41 % 15.31 % Minimum required amount(b) 4,836,901 4,812,685 129,774 December 31, 2015: Common equity Tier 1 capital Amount $ 10,485,426 $ 10,680,827 $ 476,106 Ratio(a) 11.08 % 11.33 % 86.87 % Minimum required amount(b) 4,259,977 4,242,817 24,664 Tier 1 capital Amount 12,008,232 10,680,827 476,106 Ratio(a) 12.68 % 11.33 % 86.87 % Minimum required amount(b) 5,679,969 5,657,089 32,886 Total capital Amount 14,128,454 12,589,917 480,415 Ratio(a) 14.92 % 13.35 % 87.65 % Minimum required amount(b) 7,573,292 7,542,786 43,848 Leverage Amount 12,008,232 10,680,827 476,106 Ratio(c) 10.89 % 9.75 % 22.38 % Minimum required amount(b) 4,408,971 4,381,617 85,082 (a) The ratio of capital to risk-weighted assets, as defined by regulation. (b) Minimum amount of capital to be considered adequately capitalized, as defined by regulation and including transition portion of the capital conservation buffer for 2016. (c) The ratio of capital to average assets, as defined by regulation.

Relationship with Bayview Lendi

Relationship with Bayview Lending Group LLC and Bayview Financial Holdings, L.P.	12 Months Ended
	Dec. 31, 2016
Text Block [Abstract]
Relationship with Bayview Lending Group LLC and Bayview Financial Holdings, L.P.	24. Relationship with Bayview Lending Group LLC and Bayview Financial Holdings, L.P. M&T holds a 20% minority interest in Bayview Lending Group LLC (“BLG”), a privately-held commercial mortgage company. M&T recognizes income or loss from BLG using the equity method of accounting. The carrying value of that investment was $12 million at December 31, 2016. Bayview Financial Holdings, L.P. (together with its affiliates, “Bayview Financial”), a privately-held specialty financial company, is BLG’s majority investor. In addition to their common investment in BLG, the Company and Bayview Financial conduct other business activities with each other. The Company has obtained loan servicing rights for mortgage loans from BLG and Bayview Financial having outstanding principal balances of $3.5 billion and $4.1 billion at December 31, 2016 and 2015, respectively. Revenues from those servicing rights were $19 million, $23 million and $26 million during 2016, 2015 and 2014, respectively. The Company sub-services residential real estate loans for Bayview Financial having outstanding principal balances totaling $30.4 billion and $37.7 billion at December 31, 2016 and 2015, respectively. Revenues earned for sub-servicing loans for Bayview Financial were $98 million in 2016 and $115 million in each of 2015 and 2014. In addition, the Company held $158 million and $181 million of mortgage-backed securities in its held-to-maturity portfolio at December 31, 2016 and 2015, respectively, that were securitized by Bayview Financial.

Parent company financial statem

Parent company financial statements	12 Months Ended
	Dec. 31, 2016
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Parent company financial statements	25. Parent company financial statements Condensed Balance Sheet December 31 2016 2015 (In thousands) Assets Cash in subsidiary bank $ 15,003 $ 19,874 Due from consolidated bank subsidiaries Money-market savings 1,767,184 865,274 Current income tax receivable 3,061 572 Other — 10 Total due from consolidated bank subsidiaries 1,770,245 865,856 Investments in consolidated subsidiaries Banks 15,003,964 15,581,931 Other 161,201 149,178 Investments in unconsolidated subsidiaries (note 19) 23,643 23,824 Investment in Bayview Lending Group LLC 11,908 30,264 Other assets 71,687 73,147 Total assets $ 17,057,651 $ 16,744,074 Liabilities Accrued expenses and other liabilities $ 54,487 $ 56,796 Long-term borrowings 516,542 513,989 Total liabilities 571,029 570,785 Shareholders’ equity 16,486,622 16,173,289 Total liabilities and shareholders’ equity $ 17,057,651 $ 16,744,074 Condensed Statement of Income Year Ended December 31 2016 2015 2014 (In thousands, except per share) Income Dividends from consolidated bank subsidiaries $ 1,930,000 $ 480,000 $ 480,000 Equity in earnings of Bayview Lending Group LLC (10,752 ) (14,267 ) (16,672 ) Other income 5,530 2,364 7,755 Total income 1,924,778 468,097 471,083 Expense Interest on long-term borrowings 18,963 24,453 47,700 Other expense 21,361 16,793 15,107 Total expense 40,324 41,246 62,807 Income before income taxes and equity in undistributed income of subsidiaries 1,884,454 426,851 408,276 Income tax credits 17,247 19,965 27,284 Income before equity in undistributed income of subsidiaries 1,901,701 446,816 435,560 Equity in undistributed income of subsidiaries Net income of subsidiaries 1,343,413 1,112,851 1,110,686 Less: dividends received (1,930,000 ) (480,000 ) (480,000 ) Equity in undistributed income of subsidiaries (586,587 ) 632,851 630,686 Net income $ 1,315,114 $ 1,079,667 $ 1,066,246 Net income per common share Basic $ 7.80 $ 7.22 $ 7.47 Diluted 7.78 7.18 7.42 Condensed Statement of Cash Flows Year Ended December 31 2016 2015 2014 (In thousands) Cash flows from operating activities Net income $ 1,315,114 $ 1,079,667 $ 1,066,246 Adjustments to reconcile net income to net cash provided by operating activities Equity in undistributed income of subsidiaries 586,587 (632,851 ) (630,686 ) Provision for deferred income taxes (3,157 ) (3,655 ) (6,522 ) Net change in accrued income and expense 12,898 21,780 23,419 Loss (gain) on sale of assets (2,342 ) 119 — Net cash provided by operating activities 1,909,100 465,060 452,457 Cash flows from investing activities Proceeds from sales or maturities of investment securities 51 755 — Other, net 13,619 14,038 10,721 Net cash provided by investing activities 13,670 14,793 10,721 Cash flows from financing activities Payments on long-term borrowings — (322,621 ) (350,010 ) Purchases of treasury stock (641,334 ) — — Dividends paid — common (441,891 ) (375,017 ) (371,199 ) Dividends paid — preferred (81,270 ) (81,270 ) (70,234 ) Redemption of Series D preferred stock (500,000 ) — — Proceeds from issuance of preferred stock 495,000 — 346,500 Other, net 143,764 76,364 110,601 Net cash used by financing activities (1,025,731 ) (702,544 ) (334,342 ) Net increase (decrease) in cash and cash equivalents 897,039 (222,691 ) 128,836 Cash and cash equivalents at beginning of year 885,148 1,107,839 979,003 Cash and cash equivalents at end of year $ 1,782,187 $ 885,148 $ 1,107,839 Supplemental disclosure of cash flow information Interest received during the year $ 1,931 $ 1,905 $ 2,094 Interest paid during the year 15,918 30,420 47,003 Income taxes received during the year 8,877 16,696 24,588

Recent accounting developments

Recent accounting developments	12 Months Ended
	Dec. 31, 2016
Accounting Changes And Error Corrections [Abstract]
Recent accounting developments	26. Recent accounting developments Effective January 1, 2016, the Company adopted amended accounting guidance relating to the consolidation of variable interest entities that modifies the evaluation of whether limited partnerships and similar legal entities are variable interest entities or voting interest entities and eliminates the presumption that a general partner should consolidate a limited partnership. The amended guidance also eliminates certain conditions in the assessment of whether fees paid by a legal entity to a decision maker or a service provider represent a variable interest in the legal entity and reduces the extent to which related party arrangements cause an entity to be considered a primary beneficiary. The new guidance eliminates the indefinite deferral of existing consolidation guidance for certain investment funds, but provides a scope exception for reporting entities with interests in legal entities that are required to comply with or operate in accordance with requirements similar to those in Rule 2a-7 of the Investment Company Act of 1940 for registered money market funds. The adoption of this guidance did not have a material effect on the Company’s consolidated financial position or results of operations. In January 2016, the Company also adopted amended accounting guidance for debt issuance costs. The guidance requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability. The adoption of this guidance did not have a material effect on the Company’s consolidated financial position at January 1, 2016. In the first quarter of 2016, the Company adopted amended accounting guidance for share-based payments when the terms of an award provide that a performance target could be achieved after the requisite service period. The amended guidance requires that a performance target that affects vesting and that could be achieved after the requisite service period be treated as a performance condition. The performance target should not be reflected in estimating the grant-date fair value of the award. Compensation cost should be recognized in the period in which it becomes probable that the performance target will be achieved and should represent the compensation cost attributable to the period(s) for which the requisite service has already been rendered. If the performance target becomes probable of being achieved before the end of the requisite service period, the remaining unrecognized compensation cost should be recognized prospectively over the remaining requisite service period. The total amount of compensation cost recognized during and after the requisite service period should reflect the number of awards that are expected to vest and should be adjusted to reflect those awards that ultimately vest. The requisite service period ends when the employee can cease rendering service and still be eligible to vest in the award if the performance target is achieved. The adoption of this guidance did not have a material effect on the Company’s consolidated financial position or results of operations. Amended accounting guidance for measurement-period adjustments related to business combinations was also adopted by the Company in the first quarter of 2016. The amended guidance requires that an acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amounts are determined. The acquirer is now required to record, in the same period’s financial statements, the effect on earnings of changes in depreciation, amortization, or other income effects, if any, as a result of the change to the provisional amounts, calculated as if the accounting had been completed at the acquisition date. The adoption of this guidance did not have a material effect on the Company’s consolidated financial position or results of operations. In January 2017, the Financial Accounting Standards Board (“FASB”) issued amended guidance eliminating Step 2 from the goodwill impairment test. Under the amendments to the guidance, an entity should perform its goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value. The loss recognized, however, should not exceed the total amount of goodwill allocated to that reporting unit. Additionally, an entity should consider income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if applicable. The guidance is effective for annual periods or any interim goodwill impairment tests beginning after December 15, 2019 using a prospective transition method. Early adoption is permitted. The Company does not expect the guidance will have a material impact on its consolidated financial statements, unless at some point in the future one of its reporting units were to fail step 1 of the goodwill impairment test. In January 2017, the FASB issued amended guidance clarifying the definition of a business for purposes of evaluating whether transactions would be accounted for as acquisitions (or disposals) of assets or businesses. The amendments provide a screen to determine when a set of assets and activities (collectively referred to as a “set”) is not a business. The screen requires that when substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or group of similar assets, the set is not a business. If the screen is not met, the amendments (1) require that to be considered a business, a set must include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create output, and (2) remove the evaluation of whether a market participant could replace missing elements. The guidance is effective for annual periods and interim periods within those annual periods beginning after December 15, 2017 using a prospective transition method. The Company does not expect the guidance to have a material impact on its consolidated financial statements. In November 2016, the FASB issued amended guidance for the presentation of restricted cash in the statement of cash flows. The guidance requires that restricted cash and restricted cash equivalents be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. In addition, when cash, cash equivalents, and restricted cash or restricted cash equivalents are presented in more than one line item within the statement of financial position, the line items and amounts must be presented on the face of the statement of cash flows or disclosed in the notes to the financial statements. Information about the nature of restrictions on an entity’s cash and cash equivalents must also be disclosed. The guidance is effective for annual periods and interim periods within those annual periods beginning after December 15, 2017, using a retrospective transition method. The Company is evaluating the impact the guidance may have on the presentation of its consolidated statement of cash flows. In August 2016, the FASB issued amended guidance for how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The guidance addresses the following eight specific cash flow issues: 1) cash payments for debt extinguishment costs should be classified as cash outflows for financing activities; 2) for zero-coupon debt instruments, the portion of the cash payment attributable to the accreted interest should be classified as a cash outflow for operating activities; 3) contingent consideration payments made after a business combination should be classified based on the timing of the payment; 4) cash proceeds received from the settlement of insurance claims should be classified on the basis of the related insurance coverage; 5) cash proceeds received from the settlement of corporate-owned and bank-owned life insurance policies should be classified as cash inflows from investing activities; 6) when the equity method is applied, an accounting policy election should be made to classify distributions received using either the cumulative earnings approach or the nature of the distribution approach; 7) cash receipts from payments on a transferor’s beneficial interests obtained in a securitization of financial assets should be classified as cash inflows from investing activities; and 8) the classification of cash receipts and payments that have aspects of more than one class of cash flows should be determined by applying specific guidance in GAAP. The guidance is effective for annual periods and interim periods within those annual periods beginning after December 15, 2017. The Company is evaluating the impact the guidance may have on the presentation within its consolidated statement of cash flows. In June 2016, the FASB issued amended guidance for the measurement of credit losses on certain financial assets. The amended guidance requires financial assets measured at amortized cost to be presented at the net amount expected to be collected. The allowance for credit losses will represent a valuation account that is deducted from the amortized cost basis of the financial assets to present their net carrying value at the amount expected to be collected. The income statement will reflect the measurement of credit losses for newly recognized financial assets as well as expected increases or decreases of expected credit losses that have taken place during the period. When determining the allowance, expected credit losses over the contractual term of the financial asset(s) (taking into account prepayments) will be estimated considering relevant information about past events, current conditions, and reasonable and supportable forecasts that affect the collectibility of the reported amount. The amended guidance also requires recording an allowance for credit losses for purchased financial assets with a more-than-insignificant amount of credit deterioration since origination. The initial allowance for these assets will be added to the purchase price at acquisition rather than being reported as an expense. Subsequent changes in the allowance will be recorded through the income statement as an expense adjustment. In addition, the amended guidance requires credit losses relating to available-for-sale debt securities to be recorded through an allowance for credit losses. The calculation of credit losses for available-for-sale securities will be similar to how it is determined under existing guidance. The guidance is effective for annual periods and interim periods within those annual periods beginning after December 15, 2019. The Company is assessing the new guidance to determine what modifications to existing credit estimation processes may be required. The Company expects that the new guidance will result in an increase in its allowance for credit losses as a result of considering credit losses over the expected life of its loan portfolios. Increases in the level of the allowance for credit losses will also reflect new requirements to include the nonaccretable principal difference on purchased credit impaired loans and estimated credit losses on investment securities classified as held-to-maturity, if any. The Company is still evaluating the extent of the increase to the allowance for credit losses and the impact to its financial statements. In March 2016, the FASB issued amended accounting guidance for share-based transactions. The amended guidance requires that all excess tax benefits and tax deficiencies be recognized as income tax expense or benefit in the income statement and that such amounts be recognized in the period in which the tax deduction arises or in the period in which an expiration of an award occurs. The guidance allows an entity to make an accounting policy election to either estimate the number of awards that are expected to vest or account for forfeitures when they occur. The guidance permits share-based awards that allow for the withholding of shares up to the maximum statutory tax rate in applicable jurisdictions to qualify for equity classification. The previous GAAP threshold was restricted to the employer’s minimum statutory withholding requirements. The guidance also specifies certain changes to the reporting of share-based transactions on the statement of cash flows and is effective for annual periods and interim periods within those annual periods beginning after December 15, 2016. The Company expects adoption of the guidance will result in increased volatility to reported income tax expense related to excess tax benefits and tax deficiencies for share-based transactions, but the actual amounts recognized in tax expense will be dependent on the amount of share-based transactions entered into and the stock price at the time of vesting. In March 2016, the FASB issued amended accounting guidance for the transition to the equity method of accounting. The amended guidance eliminates the requirement that when an investment qualifies for use of the equity method as a result of an increase in the level of ownership interest or degree of influence, an investor must adjust the investment, results of operations, and retained earnings retroactively on a step-by-step basis as if the equity method has been in effect during all previous periods that the investment had been held. Instead, the amended guidance requires the investor to adopt the equity method of accounting as of the date the investment first qualifies for such accounting. The guidance is effective for annual periods and interim periods within those annual periods beginning after December 15, 2016. The Company does not expect the guidance to have a material impact on its consolidated financial statements. In March 2016, the FASB issued two amendments to its rules on accounting for derivatives and hedging. The first amendment clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument does not, in and of itself, require dedesignation of that hedging relationship provided that all other hedge accounting criteria continue to be met. The second amendment clarifies the requirements for assessing whether contingent call (put) options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts. An entity performing the assessment is required to assess the embedded call (put) options solely in accordance with a four-step decision sequence and no longer has to assess whether the event that triggers the ability to exercise the option is related to interest rates or credit risks. Both amendments are effective for annual periods and interim periods within those annual periods beginning after December 15, 2016, with early adoption permitted. The Company does not expect the guidance to have a material impact on its consolidated financial statements. In February 2016, the FASB issued guidance related to the accounting for leases. The core principle of the guidance is that all leases create an asset and a liability for the lessee and, therefore, lease assets and lease liabilities should be recognized in the balance sheet. Lease assets will be recognized as a right-of-use asset and lease liabilities will be recognized as a liability to make lease payments. While the guidance requires all leases to be recognized in the balance sheet, there continues to be a differentiation between finance leases and operating leases for purposes of income statement recognition and cash flow statement presentation. For finance leases, interest on the lease liability and amortization of the right-of-use asset will be recognized separately in the statement of income. Repayments of principal on those lease liabilities will be classified within financing activities and payments of interest on the lease liability will be classified within operating activities in the statement of cash flows. For operating leases, a single lease cost is recognized in the statement of income and allocated over the lease term, generally on a straight-line basis. All cash payments are presented within operating activities in the statement of cash flows. The accounting applied by lessors is largely unchanged from existing GAAP, however, the guidance eliminates the accounting model for leveraged leases for leases that commence after the effective date of the guidance. The guidance is effective for annual periods beginning after December 15, 2018, including interim periods within those fiscal years. The Company occupies certain banking offices and uses certain equipment under noncancelable operating lease agreements, which currently are not reflected in its consolidated balance sheet. Upon adoption of the guidance, the Company expects to report increased assets and increased liabilities as a result of recognizing right-of-use assets and lease liabilities on its consolidated balance sheet. As described in note 21 of the Notes to Financial Statements, the Company is committed to $467 million of minimum lease payments under noncancelable operating lease agreements at December 31, 2016. The Company does not expect the new guidance will have a material impact to its consolidated statement of income. In January 2016, the FASB issued amended guidance related to recognition and measurement of financial assets and liabilities. The amended guidance requires that equity investments (excluding those accounted for under the equity method of accounting or those that result in consolidation of the investee) be measured at fair value with changes in fair value recognized in net income. An entity can elect to measure equity investments that do not have readily determinable fair values at cost less impairment, plus or minus changes resulting from observable price changes in orderly transactions for the identical or similar investment of the same issuer. The impairment assessment of equity investments without readily determinable fair values is simplified by requiring a qualitative assessment to identify impairment. When a qualitative assessment indicates impairment exists, an entity is required to measure the investment at fair value. The guidance eliminates the requirement for public business entities to disclose the method and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet. Further, the guidance requires public entities to use the exit price when measuring the fair value of financial instruments for disclosure purposes. The guidance also requires an entity to present separately in other comprehensive income, a change in the instrument-specific credit risk when the entity has elected to measure a liability at fair value in accordance with the fair value option. Separate presentation of financial assets and liabilities by measurement category and type of instrument on the balance sheet or accompanying notes to the financial statements is required. The guidance also clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity’s other deferred tax assets. This guidance is effective for annual periods and interim periods within those annual periods beginning after December 15, 2017. The Company is still evaluating the impact the guidance could have on its consolidated financial statements, however, it does hold certain equity securities in its available-for-sale portfolio. Upon adoption of this guidance, fair value changes in such equity securities will be recognized in the consolidated statement of income as opposed to accumulated other comprehensive income where they are recognized under current accounting guidance. In May 2014, the FASB issued amended accounting and disclosure guidance for revenue from contracts with customers. The core principle of the accounting guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle, an entity should apply the following steps: (1) identify the contract(s) with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; (5) recognize revenue when (or as) the entity satisfies a performance obligation. The guidance also specifies the accounting for some costs to obtain or fulfill a contract with a customer. The amended disclosure guidance requires sufficient information to enable users of financial statements to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. In August 2015, the FASB deferred the effective date of this guidance by one year. The amended guidance is now effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. The guidance should be applied either retrospectively to each prior reporting period presented or retrospectively with the cumulative effect of initially applying this guidance recognized at the date of initial application (the “modified retrospective approach”). At present, the Company expects to adopt the revenue recognition guidance in the first quarter of 2018 using the modified retrospective approach. A significant amount of the Company’s revenues are derived from net interest income on financial assets and liabilities, which are excluded from the scope of the amended guidance. With respect to noninterest income, the Company has identified revenue streams within the scope of the guidance, and is performing an evaluation of the underlying revenue contracts. To date, the Company has not yet identified any material changes in the timing of revenue recognition when considering the amended accounting guidance, however, the Company’s implementation efforts are ongoing and such assessments may change prior to the January 1, 2018 implementation date.

Significant accounting polici35

Significant accounting policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Consolidation	Consolidation The consolidated financial statements include M&T and all of its subsidiaries. All significant intercompany accounts and transactions of consolidated subsidiaries have been eliminated in consolidation. The financial statements of M&T included in note 25 report investments in subsidiaries under the equity method. Information about some limited purpose entities that are affiliates of the Company but are not included in the consolidated financial statements appears in note 19.
Consolidated Statement of Cash Flows	Consolidated Statement of Cash Flows For purposes of this statement, cash and due from banks and federal funds sold are considered cash and cash equivalents.
Securities purchased under agreements to resell and securities sold under agreements to repurchase	Securities purchased under agreements to resell and securities sold under agreements to repurchase Securities purchased under agreements to resell and securities sold under agreements to repurchase are treated as collateralized financing transactions and are recorded at amounts equal to the cash or other consideration exchanged. It is generally the Company’s policy to take possession of collateral pledged to secure agreements to resell.
Trading account	Trading account Financial instruments used for trading purposes are stated at fair value. Realized gains and losses and unrealized changes in fair value of financial instruments utilized in trading activities are included in “trading account and foreign exchange gains” in the consolidated statement of income.
Investment securities	Investment securities Investments in debt securities are classified as held to maturity and stated at amortized cost when management has the positive intent and ability to hold such securities to maturity. Investments in other debt securities and equity securities having readily determinable fair values are classified as available for sale and stated at estimated fair value. Amortization of premiums and accretion of discounts for investment securities available for sale and held to maturity are included in interest income. Other securities are stated at cost and include stock of the Federal Reserve Bank of New York and the Federal Home Loan Bank (“FHLB”) of New York. The cost basis of individual securities is written down through a charge to earnings when declines in value below amortized cost are considered to be other than temporary. In cases where fair value is less than amortized cost and the Company intends to sell a debt security, it is more likely than not to be required to sell a debt security before recovery of its amortized cost basis, or the Company does not expect to recover the entire amortized cost basis of a debt security, an other-than-temporary impairment is considered to have occurred. If the Company intends to sell the debt security or more likely than not will be required to sell the security before recovery of its amortized cost basis, the other-than-temporary impairment is recognized in earnings equal to the entire difference between the debt security’s amortized cost basis and its fair value. If the Company does not expect to recover the entire amortized cost basis of the security, the Company does not intend to sell the security and it is not more likely than not that the Company will be required to sell the security before recovery of its amortized cost basis, the other-than-temporary impairment is separated into (a) the amount representing the credit loss and (b) the amount related to all other factors. The amount of the other-than-temporary impairment related to the credit loss is recognized in earnings while the amount related to other factors is recognized in other comprehensive income, net of applicable taxes. Subsequently, the Company accounts for the other-than-temporarily impaired debt security as if the security had been purchased on the measurement date of the other-than-temporary impairment at an amortized cost basis equal to the previous amortized cost basis less the other-than-temporary impairment recognized in earnings. The cost basis of individual equity securities is written down to estimated fair value through a charge to earnings when declines in value below cost are considered to be other than temporary. Realized gains and losses on the sales of investment securities are determined using the specific identification method.
Loans and leases	Loans and leases The Company’s accounting methods for loans depends on whether the loans were originated by the Company or were acquired in a business combination. Originated loans and leases Interest income on loans is accrued on a level yield method. Loans are placed on nonaccrual status and previously accrued interest thereon is charged against income when principal or interest is delinquent 90 days, unless management determines that the loan status clearly warrants other treatment. Nonaccrual commercial loans and commercial real estate loans are returned to accrual status when borrowers have demonstrated an ability to repay their loans and there are no delinquent principal and interest payments. Consumer loans not secured by residential real estate are returned to accrual status when all past due principal and interest payments have been paid by the borrower. Loans secured by residential real estate are returned to accrual status when they are deemed to have an insignificant delay in payments of 90 days or less. Loan balances are charged off when it becomes evident that such balances are not fully collectible. For commercial loans and commercial real estate loans, charge-offs are recognized after an assessment by credit personnel of the capacity and willingness of the borrower to repay, the estimated value of any collateral, and any other potential sources of repayment. A charge-off is recognized when, after such assessment, it becomes evident that the loan balance is not fully collectible. For loans secured by residential real estate, the excess of the loan balances over the net realizable value of the property collateralizing the loan is charged-off when the loan becomes 150 days delinquent. Consumer loans are generally charged-off when the loans are 91 to 180 days past due, depending on whether the loan is collateralized and the status of repossession activities with respect to such collateral. Loan fees and certain direct loan origination costs are deferred and recognized as an interest yield adjustment over the life of the loan. Net deferred fees have been included in unearned discount as a reduction of loans outstanding. Commitments to sell real estate loans are utilized by the Company to hedge the exposure to changes in fair value of real estate loans held for sale. The carrying value of hedged real estate loans held for sale recorded in the consolidated balance sheet includes changes in estimated fair market value during the hedge period, typically from the date of close through the sale date. Valuation adjustments made on these loans and commitments are included in “mortgage banking revenues.” Except for consumer and residential mortgage loans that are considered smaller balance homogenous loans and are evaluated collectively, the Company considers a loan to be impaired for purposes of applying GAAP when, based on current information and events, it is probable that the Company will be unable to collect all amounts according to the contractual terms of the loan agreement or the loan is delinquent 90 days. Regardless of loan type, the Company considers a loan to be impaired if it qualifies as a troubled debt restructuring. Impaired loans are classified as either nonaccrual or as loans renegotiated at below market rates which continue to accrue interest, provided that a credit assessment of the borrower’s financial condition results in an expectation of full repayment under the modified contractual terms. Certain loans greater than 90 days delinquent are not considered impaired if they are well-secured and in the process of collection. Loans less than 90 days delinquent are deemed to have an insignificant delay in payment and are generally not considered impaired. Impairment of a loan is measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate, the loan’s observable market price, or the fair value of collateral if the loan is collateral-dependent. Interest received on impaired loans placed on nonaccrual status is generally applied to reduce the carrying value of the loan or, if principal is considered fully collectible, recognized as interest income. Residual value estimates for commercial leases are generally determined through internal or external reviews of the leased property. The Company reviews commercial lease residual values at least annually and recognizes residual value impairments deemed to be other than temporary. Loans and leases acquired in a business combination Loans acquired in a business combination subsequent to December 31, 2008 are initially recorded at fair value with no carry-over of an acquired entity’s previously established allowance for credit losses. Purchased impaired loans represent specifically identified loans with evidence of credit deterioration for which it was probable at acquisition that the Company would be unable to collect all contractual principal and interest payments. For purchased impaired loans and other loans acquired at a discount that was, in part, attributable to credit quality, the excess of cash flows expected at acquisition over the estimated fair value of acquired loans is recognized as interest income over the remaining lives of the loans. Subsequent decreases in the expected principal cash flows require the Company to evaluate the need for additions to the Company’s allowance for credit losses. Subsequent improvements in expected cash flows result first in the recovery of any related allowance for credit losses and then in recognition of additional interest income over the then-remaining lives of the loans. For all other acquired loans, the difference between the fair value and outstanding principal balance of the loans is recognized as an adjustment to interest income over the lives of those loans. Those loans are then accounted for in a manner that is similar to originated loans.
Allowance for credit losses	Allowance for credit losses The allowance for credit losses represents, in management’s judgment, the amount of losses inherent in the loan and lease portfolio as of the balance sheet date. The allowance is determined by management’s evaluation of the loan and lease portfolio based on such factors as the differing economic risks associated with each loan category, the current financial condition of specific borrowers, the economic environment in which borrowers operate, the level of delinquent loans, the value of any collateral and, where applicable, the existence of any guarantees or indemnifications. The effects of probable decreases in expected principal cash flows on loans acquired at a discount are also considered in the establishment of the allowance for credit losses.
Assets taken in foreclosure of defaulted loans	Assets taken in foreclosure of defaulted loans Assets taken in foreclosure of defaulted loans are primarily comprised of commercial and residential real property and are included in “other assets” in the consolidated balance sheet. An in-substance repossession or foreclosure occurs and a creditor is considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan upon either (1) the creditor obtaining legal title to the residential real estate property upon completion of a foreclosure or (2) the borrower conveying all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. Upon acquisition of assets taken in satisfaction of a defaulted loan, the excess of the remaining loan balance over the asset’s estimated fair value less costs to sell is charged-off against the allowance for credit losses. Subsequent declines in value of the assets are recognized as “other costs of operations” in the consolidated statement of income.
Premises and equipment	Premises and equipment Premises and equipment are stated at cost less accumulated depreciation. Depreciation expense is computed principally using the straight-line method over the estimated useful lives of the assets.
Capitalized servicing rights	Capitalized servicing rights Capitalized servicing assets are included in “other assets” in the consolidated balance sheet. Separately recognized servicing assets are initially measured at fair value. The Company uses the amortization method to subsequently measure servicing assets. Under that method, capitalized servicing assets are charged to expense in proportion to and over the period of estimated net servicing income. To estimate the fair value of servicing rights, the Company considers market prices for similar assets and the present value of expected future cash flows associated with the servicing rights calculated using assumptions that market participants would use in estimating future servicing income and expense. Such assumptions include estimates of the cost of servicing loans, loan default rates, an appropriate discount rate, and prepayment speeds. For purposes of evaluating and measuring impairment of capitalized servicing rights, the Company stratifies such assets based on the predominant risk characteristics of the underlying financial instruments that are expected to have the most impact on projected prepayments, cost of servicing and other factors affecting future cash flows associated with the servicing rights. Such factors may include financial asset or loan type, note rate and term. The amount of impairment recognized is the amount by which the carrying value of the capitalized servicing rights for a stratum exceeds estimated fair value. Impairment is recognized through a valuation allowance.
Sales and securitizations of financial assets	Sales and securitizations of financial assets Transfers of financial assets for which the Company has surrendered control of the financial assets are accounted for as sales. Interests in a sale of financial assets that continue to be held by the Company, including servicing rights, are measured at fair value. The fair values of retained debt securities are generally determined through reference to independent pricing information. The fair values of retained servicing rights and any other retained interests are determined based on the present value of expected future cash flows associated with those interests and by reference to market prices for similar assets. Securitization structures typically require the use of special-purpose trusts that are considered variable interest entities. A variable interest entity is included in the consolidated financial statements if the Company has the power to direct the activities that most significantly impact the variable interest entity’s economic performance and has the obligation to absorb losses or the right to receive benefits of the variable interest entity that could potentially be significant to that entity.
Goodwill and core deposit and other intangible assets	Goodwill and core deposit and other intangible assets Goodwill represents the excess of the cost of an acquired entity over the fair value of the identifiable net assets acquired. Goodwill is not amortized, but rather is tested for impairment at least annually at the reporting unit level, which is either at the same level or one level below an operating segment. Other acquired intangible assets with finite lives, such as core deposit intangibles, are initially recorded at estimated fair value and are amortized over their estimated lives. Core deposit and other intangible assets are generally amortized using accelerated methods over estimated useful lives of five to ten years. The Company periodically assesses whether events or changes in circumstances indicate that the carrying amounts of core deposit and other intangible assets may be impaired.
Derivative financial instruments	Derivative financial instruments The Company accounts for derivative financial instruments at fair value. If certain conditions are met, a derivative may be specifically designated as (a) a hedge of the exposure to changes in the fair value of a recognized asset or liability or an unrecognized firm commitment, (b) a hedge of the exposure to variable cash flows of a forecasted transaction or (c) a hedge of the foreign currency exposure of a net investment in a foreign operation, an unrecognized firm commitment, an available-for-sale security, or a foreign currency denominated forecasted transaction. The Company utilizes interest rate swap agreements as part of the management of interest rate risk to modify the repricing characteristics of certain portions of its portfolios of earning assets and interest-bearing liabilities. For such agreements, amounts receivable or payable are recognized as accrued under the terms of the agreement and the net differential is recorded as an adjustment to interest income or expense of the related asset or liability. Interest rate swap agreements may be designated as either fair value hedges or cash flow hedges. In a fair value hedge, the fair values of the interest rate swap agreements and changes in the fair values of the hedged items are recorded in the Company’s consolidated balance sheet with the corresponding gain or loss recognized in current earnings. The difference between changes in the fair values of interest rate swap agreements and the hedged items represents hedge ineffectiveness and is recorded in “other revenues from operations” in the consolidated statement of income. In a cash flow hedge, the effective portion of the derivative’s unrealized gain or loss is initially recorded as a component of other comprehensive income and subsequently reclassified into earnings when the forecasted transaction affects earnings. The ineffective portion of the unrealized gain or loss is reported in “other revenues from operations” immediately. The Company utilizes commitments to sell real estate loans to hedge the exposure to changes in the fair value of real estate loans held for sale. Commitments to originate real estate loans to be held for sale and commitments to sell real estate loans are generally recorded in the consolidated balance sheet at estimated fair value. Derivative instruments not related to mortgage banking activities, including financial futures commitments and interest rate swap agreements, that do not satisfy the hedge accounting requirements are recorded at fair value and are generally classified as trading account assets or liabilities with resultant changes in fair value being recognized in “trading account and foreign exchange gains” in the consolidated statement of income.
Stock-based compensation	Stock-based compensation Stock-based compensation expense is recognized over the vesting period of the stock-based grant based on the estimated grant date value of the stock-based compensation, except that the recognition of compensation costs is accelerated for stock-based awards granted to retirement-eligible employees and employees who will become retirement-eligible prior to full vesting of the award because the Company’s incentive compensation plan allows for vesting at the time an employee retires.
Income taxes	Income taxes Deferred tax assets and liabilities are recognized for the future tax effects attributable to differences between the financial statement value of existing assets and liabilities and their respective tax bases and carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates and laws. The Company evaluates uncertain tax positions using the two-step process required by GAAP. The first step requires a determination of whether it is more likely than not that a tax position will be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. Under the second step, a tax position that meets the more-likely-than-not recognition threshold is measured at the largest amount of benefit that is greater than fifty percent likely of being realized upon ultimate settlement. The Company accounts for its investments in qualified affordable housing projects using the proportional amortization method. Under that method, the Company amortizes the initial cost of the investment in proportion to the tax credits and other tax benefits received and recognizes the net investment performance in the income statement as a component of income tax expense.
Earnings per common share	Earnings per common share Basic earnings per common share exclude dilution and are computed by dividing income available to common shareholders by the weighted-average number of common shares outstanding (exclusive of shares represented by the unvested portion of restricted stock and restricted stock unit grants) and common shares issuable under deferred compensation arrangements during the period. Diluted earnings per common share reflect shares represented by the unvested portion of restricted stock and restricted stock unit grants and the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock or resulted in the issuance of common stock that then shared in earnings. Proceeds assumed to have been received on such exercise or conversion are assumed to be used to purchase shares of M&T common stock at the average market price during the period, as required by the “treasury stock method” of accounting. GAAP requires that unvested share-based payment awards that contain nonforfeitable rights to dividends or dividend equivalents (whether paid or unpaid) shall be considered participating securities and shall be included in the computation of earnings per common share pursuant to the two-class method. The Company has issued stock-based compensation awards in the form of restricted stock and restricted stock units that contain such rights and, accordingly, the Company’s earnings per common share are calculated using the two-class method.
Treasury stock	Treasury stock Repurchases of shares of M&T common stock are recorded at cost as a reduction of shareholders’ equity. Reissuances of shares of treasury stock are recorded at average cost.

Acquisition and divestiture (Ta

Acquisition and divestiture (Tables)	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Schedule of Acquired Identifiable Assets and Liabilities Assumed	The consideration paid for Hudson City’s common equity and the amounts of identifiable assets acquired and liabilities assumed as of the acquisition date were as follows: (In thousands) Identifiable assets: Cash and due from banks $ 131,688 Interest-bearing deposits at banks 7,568,934 Investment securities 7,929,014 Loans 19,015,013 Goodwill 1,079,787 Core deposit intangible 131,665 Other assets 843,219 Total identifiable assets 36,699,320 Liabilities: Deposits 17,879,589 Borrowings 13,211,598 Other liabilities 405,025 Total liabilities 31,496,212 Total consideration $ 5,203,108 Cash paid $ 2,064,284 Common stock issued (25,953,950 shares) 3,110,581 Common stock awards converted 28,243 Total consideration $ 5,203,108
Summary of Acquired Impaired Loans	The difference between contractually required payments at acquisition and the cash flows expected to be collected at acquisition, as shown in the following table, reflected the impact of estimated credit losses and other factors, such as prepayments. November 1, 2015 (In thousands) Contractually required principal and interest at acquisition $ 1,304,366 Contractual cash flows not expected to be collected (498,919 ) Expected cash flows at acquisition 805,447 Interest component of expected cash flows (117,251 ) Estimated fair value $ 688,196
Pro Forma Information	Additionally, the Company expects to achieve further operating cost savings and other business synergies as a result of the acquisition which are not reflected in the pro forma amounts that follow. Actual Since Acquisition Through Pro Forma December 31, Year Ended December 31 2015 2015 2014 (In thousands) Total revenues(a) $ 111,168 $ 5,132,662 $ 5,406,291 Net income (loss) (21,175 ) 1,011,463 1,445,779 (a) Represents net interest income plus other income.
Summary of Merger-Related Expenses	A summary of merger-related expenses included in the consolidated statement of income for the years ended December 31, 2016 and 2015 follows: 2016 2015 (In thousands) Salaries and employee benefits $ 5,334 $ 51,287 Equipment and net occupancy 1,278 3 Outside data processing and software 1,067 785 Advertising and marketing 10,522 79 Printing, postage and supplies 1,482 504 Other cost of operations 16,072 23,318 Other expense 35,755 75,976 Provision for credit losses — 21,000 Total $ 35,755 $ 96,976

Investment securities (Tables)

Investment securities (Tables)	12 Months Ended
	Dec. 31, 2016
Investments Debt And Equity Securities [Abstract]
Amortized Cost and Estimated Fair Value of Investment Securities	The amortized cost and estimated fair value of investment securities were as follows: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value (In thousands) December 31, 2016 Investment securities available for sale: U.S. Treasury and federal agencies $ 1,912,110 $ 386 $ 9,952 $ 1,902,544 Obligations of states and political subdivisions 3,570 77 6 3,641 Mortgage-backed securities: Government issued or guaranteed 10,980,507 88,343 113,989 10,954,861 Privately issued 45 — 1 44 Other debt securities 134,105 1,407 16,996 118,516 Equity securities 307,964 45,073 571 352,466 13,338,301 135,286 141,515 13,332,072 Investment securities held to maturity: Obligations of states and political subdivisions 60,858 267 224 60,901 Mortgage-backed securities: Government issued or guaranteed 2,233,173 37,498 7,374 2,263,297 Privately issued 157,704 897 37,120 121,481 Other debt securities 5,543 — — 5,543 2,457,278 38,662 44,718 2,451,222 Other securities 461,118 — — 461,118 Total $ 16,256,697 $ 173,948 $ 186,233 $ 16,244,412 December 31, 2015 Investment securities available for sale: U.S. Treasury and federal agencies $ 299,890 $ 294 $ 187 $ 299,997 Obligations of states and political subdivisions 5,924 146 42 6,028 Mortgage-backed securities: Government issued or guaranteed 11,592,959 142,370 48,701 11,686,628 Privately issued 74 2 2 74 Collateralized debt obligations 28,438 20,143 1,188 47,393 Other debt securities 137,556 1,514 20,190 118,880 Equity securities 73,795 10,230 354 83,671 12,138,636 174,699 70,664 12,242,671 Investment securities held to maturity: Obligations of states and political subdivisions 118,431 1,003 421 119,013 Mortgage-backed securities: Government issued or guaranteed 2,553,612 50,936 7,817 2,596,731 Privately issued 181,091 2,104 41,367 141,828 Other debt securities 6,575 — — 6,575 2,859,709 54,043 49,605 2,864,147 Other securities 554,059 — — 554,059 Total $ 15,552,404 $ 228,742 $ 120,269 $ 15,660,877
Investment Ratings of All Privately Issued Mortgage-Backed Securities and Other Debt Securities	As of December 31, 2016, the latest available investment ratings of all obligations of states and political subdivisions, privately issued mortgage-backed securities and other debt securities were: Average Credit Rating of Fair Value Amount Amortized Cost Estimated Fair Value A or Better BBB BB B or Less Not Rated (In thousands) Obligations of states and political subdivisions $ 64,428 $ 64,542 $ 47,023 $ — $ — $ — $ 17,519 Privately issued mortgage-backed securities 157,749 121,525 30,760 16 — 90,730 19 Other debt securities 139,648 124,059 5,442 63,353 30,373 — 24,891 Total $ 361,825 $ 310,126 $ 83,225 $ 63,369 $ 30,373 $ 90,730 $ 42,429
Amortized Cost and Estimated Fair Value of Collateralized Mortgage Obligations	The amortized cost and estimated fair value of collateralized mortgage obligations included in mortgage-backed securities were as follows: December 31 2016 2015 (In thousands) Collateralized mortgage obligations: Amortized cost $ 162,027 $ 188,819 Estimated fair value 125,848 149,632
Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity	At December 31, 2016, the amortized cost and estimated fair value of debt securities by contractual maturity were as follows: Amortized Cost Estimated Fair Value (In thousands) Debt securities available for sale: Due in one year or less $ 157,954 $ 158,334 Due after one year through five years 1,760,301 1,750,542 Due after five years through ten years 2,689 3,132 Due after ten years 128,841 112,693 2,049,785 2,024,701 Mortgage-backed securities available for sale 10,980,552 10,954,905 $ 13,030,337 $ 12,979,606 Debt securities held to maturity: Due in one year or less $ 24,533 $ 24,643 Due after one year through five years 34,073 33,963 Due after five years through ten years 2,252 2,295 Due after ten years 5,543 5,543 66,401 66,444 Mortgage-backed securities held to maturity 2,390,877 2,384,778 $ 2,457,278 $ 2,451,222
Investment Securities in Continuous Unrealized Loss Position	A summary of investment securities that as of December 31, 2016 and 2015 had been in a continuous unrealized loss position for less than twelve months and those that had been in a continuous unrealized loss position for twelve months or longer follows: Less Than 12 Months 12 Months or More Fair Value Unrealized Losses Fair Value Unrealized Losses (In thousands) December 31, 2016 Investment securities available for sale: U.S. Treasury and federal agencies $ 1,710,241 $ (9,950 ) $ 2,295 $ (2 ) Obligations of states and political subdivisions — — 593 (6 ) Mortgage-backed securities: Government issued or guaranteed 6,730,829 (113,374 ) 81,003 (615 ) Privately issued — — 27 (1 ) Other debt securities 100 (1 ) 85,400 (16,995 ) Equity securities 17,776 (422 ) 151 (149 ) 8,458,946 (123,747 ) 169,469 (17,768 ) Investment securities held to maturity: Obligations of states and political subdivisions 17,988 (126 ) 11,891 (98 ) Mortgage-backed securities: Government issued or guaranteed 618,832 (6,842 ) 17,481 (532 ) Privately issued 17,911 (1,222 ) 57,016 (35,898 ) 654,731 (8,190 ) 86,388 (36,528 ) Total $ 9,113,677 $ (131,937 ) $ 255,857 $ (54,296 ) December 31, 2015 Investment securities available for sale: U.S. Treasury and federal agencies $ 147,508 $ (187 ) $ — $ — Obligations of states and political subdivisions 865 (2 ) 1,335 (40 ) Mortgage-backed securities: Government issued or guaranteed 4,061,899 (48,534 ) 7,216 (167 ) Privately issued — — 43 (2 ) Collateralized debt obligations 5,711 (335 ) 2,063 (853 ) Other debt securities 12,935 (462 ) 93,344 (19,728 ) Equity securities 18,073 (207 ) 153 (147 ) 4,246,991 (49,727 ) 104,154 (20,937 ) Investment securities held to maturity: Obligations of states and political subdivisions 42,913 (335 ) 5,853 (86 ) Mortgage-backed securities: Government issued or guaranteed 459,983 (1,801 ) 228,867 (6,016 ) Privately issued — — 112,155 (41,367 ) 502,896 (2,136 ) 346,875 (47,469 ) Total $ 4,749,887 $ (51,863 ) $ 451,029 $ (68,406 )

Loans and leases (Tables)

Loans and leases (Tables)	12 Months Ended
	Dec. 31, 2016
Receivables [Abstract]
Total Loans and Leases Outstanding	Total loans and leases outstanding were comprised of the following: December 31 2016 2015 (In thousands) Loans Commercial, financial, etc. $ 21,351,119 $ 19,223,419 Real estate: Residential 22,584,141 26,249,059 Commercial 25,550,057 23,592,097 Construction 8,066,756 5,716,994 Consumer 12,130,094 11,584,347 Total loans 89,682,167 86,365,916 Leases Commercial 1,419,510 1,353,318 Total loans and leases 91,101,677 87,719,234 Less: unearned discount (248,261 ) (229,735 ) Total loans and leases, net of unearned discount $ 90,853,416 $ 87,489,499
Outstanding Principal Balance and Carrying Amount of Loans and Included in Consolidated Balance Sheet	The outstanding principal balance and the carrying amount of loans acquired at a discount that were recorded at fair value at the acquisition date and included in the consolidated balance sheet were as follows: December 31 2016 2015 (In thousands) Outstanding principal balance $ 2,311,699 $ 3,122,935 Carrying amount: Commercial, financial, leasing, etc. 59,928 78,847 Commercial real estate 456,820 644,284 Residential real estate 799,802 1,016,129 Consumer 487,721 725,807 $ 1,804,271 $ 2,465,067
Summary of Changes in Accretable Yield for Acquired Loans	A summary of changes in the accretable yield for loans acquired at a discount for the years ended December 31, 2016, 2015 and 2014 follows: For the Year Ended December 31, 2016 2015 2014 Purchased Other Purchased Other Purchased Other Impaired Acquired Impaired Acquired Impaired Acquired (In thousands) Balance at beginning of period $ 184,618 $ 296,434 $ 76,518 $ 397,379 $ 37,230 $ 538,633 Additions — — 117,251 — — — Interest income (52,769 ) (123,044 ) (28,551 ) (158,260 ) (21,263 ) (178,670 ) Reclassifications from nonaccretable balance 22,384 22,677 19,400 49,930 60,551 24,907 Other(a) — 5,086 — 7,385 — 12,509 Balance at end of period $ 154,233 $ 201,153 $ 184,618 $ 296,434 $ 76,518 $ 397,379 (a) Other changes in expected cash flows including changes in interest rates and prepayment assumptions.
Summary of Current, Past Due and Nonaccrual Loans	A summary of current, past due and nonaccrual loans as of December 31, 2016 and 2015 follows: Current 30-89 Days Past Due Accruing Loans Past Due 90 Days or More(a) Accruing Loans Acquired at a Discount Past Due 90 Days or More(b) Purchased Impaired(c) Nonaccrual Total (In thousands) December 31, 2016 Commercial, financial, leasing, etc. $ 22,287,857 $ 53,503 $ 6,195 $ 417 $ 641 $ 261,434 $ 22,610,047 Real estate: Commercial 25,076,684 183,531 7,054 12,870 31,404 176,201 25,487,744 Residential builder and developer 1,884,989 4,667 5 1,952 14,006 16,707 1,922,326 Other commercial construction 5,985,118 77,701 922 198 14,274 18,111 6,096,324 Residential 17,631,377 485,468 281,298 11,537 378,549 229,242 19,017,471 Residential — limited documentation 3,239,344 88,366 — — 139,158 106,573 3,573,441 Consumer: Home equity lines and loans 5,502,091 44,565 — 12,678 — 81,815 5,641,149 Automobile 2,869,232 56,158 — 1 — 18,674 2,944,065 Other 3,491,629 31,286 5,185 21,491 — 11,258 3,560,849 Total $ 87,968,321 $ 1,025,245 $ 300,659 $ 61,144 $ 578,032 $ 920,015 $ 90,853,416 December 31, 2015 Commercial, financial, leasing, etc. $ 20,122,648 $ 52,868 $ 2,310 $ 693 $ 1,902 $ 241,917 $ 20,422,338 Real estate: Commercial(d) 23,111,673 172,439 12,963 8,790 46,790 179,606 23,532,261 Residential builder and developer 1,507,856 7,969 5,760 6,925 28,734 28,429 1,585,673 Other commercial construction(d) 3,962,620 65,932 7,936 2,001 24,525 16,363 4,079,377 Residential 20,507,551 560,312 284,451 16,079 488,599 153,281 22,010,273 Residential — limited documentation 3,885,073 137,289 — — 175,518 61,950 4,259,830 Consumer: Home equity lines and loans 5,805,222 45,604 — 15,222 2,261 84,467 5,952,776 Automobile 2,446,473 56,181 — 6 — 16,597 2,519,257 Other 3,051,435 36,702 4,021 18,757 — 16,799 3,127,714 Total $ 84,400,551 $ 1,135,296 $ 317,441 $ 68,473 $ 768,329 $ 799,409 $ 87,489,499 (a) Excludes loans acquired at a discount. (b) Loans acquired at a discount that were recorded at fair value at acquisition date. This category does not include purchased impaired loans that are presented separately. (c) Accruing loans acquired at a discount that were impaired at acquisition date and recorded at fair value. (d) The Company expanded its definition of construction loans in 2016 and, as a result, re-characterized certain commercial real estate loans as other commercial construction loans. The December 31, 2015 balances reflect such changes.
Loan Modification Activities that were Considered Troubled Debt Restructurings	The table below summarizes the Company’s loan modification activities that were considered troubled debt restructurings for the year ended December 31, 2016: Recorded Investment Financial Effects of Modification Number Pre- modification Post- modification Recorded Investment(a) Interest (b) (Dollars in thousands) Commercial, financial, leasing, etc. Principal deferral 127 $ 102,872 $ 102,446 $ (426 ) $ — Combination of concession types 37 51,221 41,673 (9,548 ) (95 ) Real estate: Commercial Principal deferral 56 24,323 23,558 (765 ) — Interest rate reduction 1 129 129 — (25 ) Other 1 4,723 4,447 (276 ) — Combination of concession types 23 15,695 15,603 (92 ) (585 ) Residential builder and developer Principal deferral 3 23,905 22,958 (947 ) — Combination of concession types 3 15,755 15,123 (632 ) — Other commercial construction Principal deferral 1 250 250 — — Combination of concession types 2 2,863 2,782 (81 ) — Residential Principal deferral 73 11,082 11,771 689 — Combination of concession types 46 8,975 9,367 392 (120 ) Residential-limited documentation Principal deferral 8 902 1,047 145 — Combination of concession types 13 2,658 2,917 259 (706 ) Consumer: Home equity lines and loans Principal deferral 10 760 761 1 — Combination of concession types 93 11,110 11,110 — (916 ) Automobile Principal deferral 117 1,124 1,124 — — Other 38 55 55 — — Combination of concession types 8 85 85 — (3 ) Other Principal deferral 57 968 968 — — Other 5 45 45 — — Combination of concession types 17 196 196 — (32 ) Total 739 $ 279,696 $ 268,415 $ (11,281 ) $ (2,482 ) (a) Financial effects impacting the recorded investment included principal payments or advances, charge-offs and capitalized escrow arrearages. (b) Represents the present value of interest rate concessions discounted at the effective rate of the original loan. The table below summarizes the Company’s loan modification activities that were considered troubled debt restructurings for the year ended December 31, 2015: Recorded Investment Financial Effects of Modification Number Pre- modification Post- modification Recorded Investment(a) Interest (b) (Dollars in thousands) Commercial, financial, leasing, etc. Principal deferral 114 $ 55,621 $ 50,807 $ (4,814 ) $ — Interest rate reduction 1 99 99 — (19 ) Other 3 12,965 12,827 (138 ) — Combination of concession types 9 32,444 31,439 (1,005 ) (245 ) Real estate: Commercial Principal deferral 49 49,486 48,388 (1,098 ) — Other 3 4,169 4,087 (82 ) — Combination of concession types 6 3,238 3,242 4 (159 ) Residential builder and developer Principal deferral 2 10,650 10,598 (52 ) — Other commercial construction Principal deferral 4 368 460 92 — Combination of concession types 2 10,375 10,375 — (49 ) Residential Principal deferral 58 6,194 6,528 334 — Other 1 267 267 — — Combination of concession types 26 4,024 4,277 253 (483 ) Residential-limited documentation Principal deferral 2 426 437 11 — Combination of concession types 9 1,536 1,635 99 (121 ) Consumer: Home equity lines and loans Principal deferral 8 2,175 2,175 — — Combination of concession types 63 5,203 5,204 1 (677 ) Automobile Principal deferral 192 1,818 1,818 — — Interest rate reduction 7 137 137 — (10 ) Other 46 150 150 — — Combination of concession types 57 948 948 — (43 ) Other Principal deferral 102 1,995 1,995 — — Other 13 116 116 — — Combination of concession types 40 396 396 — (45 ) Total 817 $ 204,800 $ 198,405 $ (6,395 ) $ (1,851 ) (a) Financial effects impacting the recorded investment included principal payments or advances, charge-offs and capitalized escrow arrearages. (b) Represents the present value of interest rate concessions discounted at the effective rate of the original loan. The table below summarizes the Company’s loan modification activities that were considered troubled debt restructurings for the year ended December 31, 2014: Recorded Investment Financial Effects of Modification Number Pre- modification Post- modification Recorded Investment(a) Interest (b) (Dollars in thousands) Commercial, financial, leasing, etc. Principal deferral 95 $ 29,035 $ 23,628 $ (5,407 ) $ — Other 3 29,912 31,604 1,692 — Combination of concession types 7 19,167 19,030 (137 ) (20 ) Real estate: Commercial Principal deferral 39 19,077 18,997 (80 ) — Interest rate reduction 1 255 252 (3 ) (48 ) Other 1 650 — (650 ) — Combination of concession types 7 1,152 1,198 46 (264 ) Residential builder and developer Principal deferral 2 1,639 1,639 — — Other commercial construction Principal deferral 4 6,703 6,611 (92 ) — Residential Principal deferral 28 2,710 2,905 195 — Interest rate reduction 11 1,146 1,222 76 (152 ) Other 1 188 188 — — Combination of concession types 30 4,211 4,287 76 (483 ) Residential-limited documentation Principal deferral 6 880 963 83 — Combination of concession types 21 3,806 3,846 40 (386 ) Consumer: Home equity lines and loans Principal deferral 3 280 280 — — Interest rate reduction 6 535 535 — (120 ) Combination of concession types 47 5,031 5,031 — (560 ) Automobile Principal deferral 208 3,293 3,293 — — Interest rate reduction 9 152 152 — (12 ) Other 42 255 255 — — Combination of concession types 81 1,189 1,189 — (100 ) Other Principal deferral 33 245 245 — — Interest rate reduction 4 293 293 — (63 ) Other 1 45 45 — — Combination of concession types 70 2,502 2,502 — (761 ) Total 760 $ 134,351 $ 130,190 $ (4,161 ) $ (2,969 ) (a) Financial effects impacting the recorded investment included principal payments or advances, charge-offs and capitalized escrow arrearages. (b) Represents the present value of interest rate concessions discounted at the effective rate of the original loan.
Summary of Lease Financing Receivables	A summary of lease financing receivables follows: December 31 2016 2015 (In thousands) Commercial leases: Direct financings: Lease payments receivable $ 1,136,815 $ 1,058,605 Estimated residual value of leased assets 79,449 81,269 Unearned income (107,535 ) (102,723 ) Investment in direct financings 1,108,729 1,037,151 Leveraged leases: Lease payments receivable 92,918 95,316 Estimated residual value of leased assets 110,328 118,128 Unearned income (38,760 ) (41,556 ) Investment in leveraged leases 164,486 171,888 Total investment in leases $ 1,273,215 $ 1,209,039 Deferred taxes payable arising from leveraged leases $ 139,067 $ 160,603
Minimum Future Lease Payments to be Received from Lease Financings	At December 31, 2016, the minimum future lease payments to be received from lease financings were as follows: (In thousands) Year ending December 31: 2017 $ 301,611 2018 276,524 2019 209,835 2020 150,631 2021 101,403 Later years 189,729 $ 1,229,733

Allowance for credit losses (Ta

Allowance for credit losses (Tables)	12 Months Ended
	Dec. 31, 2016
Receivables [Abstract]
Changes in Allowance for Credit Losses	Changes in the allowance for credit losses for the years ended December 31, 2016, 2015 and 2014 were as follows: Commercial, Financial, Real Estate 2016 Leasing, etc. Commercial Residential Consumer Unallocated Total (In thousands) Beginning balance $ 300,404 326,831 72,238 178,320 78,199 $ 955,992 Provision for credit losses 59,506 33,627 6,902 90,134 (169 ) 190,000 Net charge-offs Charge-offs (59,244 ) (4,805 ) (26,133 ) (141,073 ) — (231,255 ) Recoveries 30,167 7,066 8,120 28,907 — 74,260 Net (charge-offs) recoveries (29,077 ) 2,261 (18,013 ) (112,166 ) — (156,995 ) Ending balance $ 330,833 362,719 61,127 156,288 78,030 $ 988,997 Commercial, Financial, Real Estate 2015 Leasing, etc. Commercial Residential Consumer Unallocated Total (In thousands) Beginning balance $ 288,038 307,927 61,910 186,033 75,654 $ 919,562 Provision for credit losses 43,065 25,768 19,133 79,489 2,545 170,000 Net charge-offs Charge-offs (60,983 ) (16,487 ) (13,116 ) (107,787 ) — (198,373 ) Recoveries 30,284 9,623 4,311 20,585 — 64,803 Net charge-offs (30,699 ) (6,864 ) (8,805 ) (87,202 ) — (133,570 ) Ending balance $ 300,404 326,831 72,238 178,320 78,199 $ 955,992 2014 Beginning balance $ 273,383 324,978 78,656 164,644 75,015 $ 916,676 Provision for credit losses 51,410 (13,779 ) (3,974 ) 89,704 639 124,000 Net charge-offs Charge-offs (58,943 ) (14,058 ) (21,351 ) (84,390 ) — (178,742 ) Recoveries 22,188 10,786 8,579 16,075 — 57,628 Net charge-offs (36,755 ) (3,272 ) (12,772 ) (68,315 ) — (121,114 ) Ending balance $ 288,038 307,927 61,910 186,033 75,654 $ 919,562
Impaired Loans and Leases	The following tables provide information with respect to loans and leases that were considered impaired as of December 31, 2016 and 2015 and for the years ended December 31, 2016, 2015 and 2014.
Interest Income Recognized on Impaired Loans	Year Ended December 31, 2016 Year Ended December 31, 2015 Interest Income Recognized Interest Income Recognized Average Recorded Investment Total Cash Basis Average Recorded Investment Total Cash Basis (In thousands) Commercial, financial, leasing, etc. $ 277,647 8,342 8,342 236,201 2,933 2,933 Real estate: Commercial 175,877 4,878 4,878 166,628 6,243 6,243 Residential builder and developer 29,237 2,300 2,300 59,457 335 335 Other commercial construction 19,697 644 644 20,276 2,311 2,311 Residential 98,394 6,227 3,154 101,483 6,188 4,037 Residential-limited documentation 103,060 5,999 1,975 118,449 6,380 2,638 Consumer: Home equity lines and loans 36,493 1,325 410 21,523 905 261 Automobile 19,636 1,242 99 25,675 1,619 175 Other 9,218 440 83 18,809 729 113 Total $ 769,259 31,397 21,885 768,501 27,643 19,046 Year Ended December 31, 2014 Interest Income Recognized Average Recorded Investment Total Cash Basis (In thousands) Commercial, financial, leasing, etc. $ 181,932 2,251 2,251 Real estate: Commercial 184,773 4,029 4,029 Residential builder and developer 91,149 142 142 Other commercial construction 62,734 1,893 1,893 Residential 126,005 9,180 6,978 Residential-limited documentation 133,800 6,613 2,546 Consumer: Home equity lines and loans 18,083 750 248 Automobile 35,173 2,251 295 Other 18,378 690 191 Total $ 852,027 27,799 18,573
Summary of Loan Grades	The following table summarizes the loan grades applied to the various classes of the Company’s commercial loans and commercial real estate loans. Real Estate Commercial, Residential Other Financial, Builder and Commercial Leasing, etc. Commercial Developer Construction (In thousands) December 31, 2016 Pass $ 21,398,581 24,570,269 1,789,071 5,912,351 Criticized accrual 950,032 741,274 116,548 165,862 Criticized nonaccrual 261,434 176,201 16,707 18,111 Total $ 22,610,047 25,487,744 1,922,326 6,096,324 December 31, 2015 Pass $ 19,442,183 22,697,398 1,497,465 3,834,137 Criticized accrual 738,238 655,257 59,779 228,877 Criticized nonaccrual 241,917 179,606 28,429 16,363 Total $ 20,422,338 23,532,261 1,585,673 4,079,377
Allocation of Allowance for Credit Losses on Basis of Company's Impairment Methodology	The allocation of the allowance for credit losses summarized on the basis of the Company’s impairment methodology was as follows: Commercial, Financial, Real Estate Leasing, etc. Commercial Residential Consumer Total (In thousands) December 31, 2016 Individually evaluated for impairment $ 48,480 12,500 9,457 12,543 $ 82,980 Collectively evaluated for impairment 282,353 348,301 47,993 143,745 822,392 Purchased impaired — 1,918 3,677 — 5,595 Allocated $ 330,833 362,719 61,127 156,288 910,967 Unallocated 78,030 Total $ 988,997 December 31, 2015 Individually evaluated for impairment $ 44,752 19,175 12,727 13,306 $ 89,960 Collectively evaluated for impairment 255,615 307,000 57,624 163,511 783,750 Purchased impaired 37 656 1,887 1,503 4,083 Allocated $ 300,404 326,831 72,238 178,320 877,793 Unallocated 78,199 Total $ 955,992
Recorded Investment in Loans and Leases on Basis of Company's Impairment Methodology	The recorded investment in loans and leases summarized on the basis of the Company’s impairment methodology was as follows: Commercial, Financial, Real Estate Leasing, etc. Commercial Residential Consumer Total (In thousands) December 31, 2016 Individually evaluated for impairment $ 268,877 224,630 201,479 65,466 $ 760,452 Collectively evaluated for impairment 22,340,529 33,222,080 21,871,726 12,080,597 89,514,932 Purchased impaired 641 59,684 517,707 — 578,032 Total $ 22,610,047 33,506,394 22,590,912 12,146,063 $ 90,853,416 December 31, 2015 Individually evaluated for impairment $ 272,227 234,132 207,949 65,365 $ 779,673 Collectively evaluated for impairment 20,148,209 28,863,130 25,398,037 11,532,121 85,941,497 Purchased impaired 1,902 100,049 664,117 2,261 768,329 Total $ 20,422,338 29,197,311 26,270,103 11,599,747 $ 87,489,499

Premises and equipment (Tables)

Premises and equipment (Tables)	12 Months Ended
	Dec. 31, 2016
Property Plant And Equipment [Abstract]
Summary of Premises and Equipment	The detail of premises and equipment was as follows: December 31 2016 2015 (In thousands) Land $ 104,671 $ 105,435 Buildings — owned 448,442 443,507 Buildings — capital leases — 1,108 Leasehold improvements 232,936 229,919 Furniture and equipment — owned 636,219 614,591 Furniture and equipment — capital leases 14,849 12,019 1,437,117 1,406,579 Less: accumulated depreciation and amortization Owned assets 756,245 732,315 Capital leases 5,609 7,582 761,854 739,897 Premises and equipment, net $ 675,263 $ 666,682

Capitalized servicing assets (T

Capitalized servicing assets (Tables)	12 Months Ended
	Dec. 31, 2016
Transfers And Servicing [Abstract]
Servicing Asset at Amortized Cost	Changes in capitalized servicing assets were as follows: Residential Mortgage Loans Commercial Mortgage Loans For the Year Ended December 31, 2016 2015 2014 2016 2015 2014 (In thousands) Beginning balance $ 118,303 $ 109,871 $ 126,377 $ 83,692 $ 72,939 $ 72,499 Originations 28,618 35,556 28,285 40,117 29,914 15,922 Purchases 638 243 289 — — 730 Amortization (30,208 ) (27,367 ) (45,080 ) (20,045 ) (19,161 ) (16,212 ) 117,351 118,303 109,871 103,764 83,692 72,939 Valuation allowance — — — — — — Ending balance, net $ 117,351 $ 118,303 $ 109,871 $ 103,764 $ 83,692 $ 72,939 Other Total For the Year Ended December 31, 2016 2015 2014 2016 2015 2014 (In thousands) Beginning balance $ 729 $ 4,107 $ 11,225 $ 202,724 $ 186,917 $ 210,101 Originations — — — 68,735 65,470 44,207 Purchases — — — 638 243 1,019 Amortization (729 ) (3,378 ) (7,118 ) (50,982 ) (49,906 ) (68,410 ) — 729 4,107 221,115 202,724 186,917 Valuation allowance — — — — — — Ending balance, net $ — $ 729 $ 4,107 $ 221,115 $ 202,724 $ 186,917
Economic Assumptions Used to Determine Fair Value of Capitalized Servicing Rights and Sensitivity of Value to Changes in Assumptions	Residential Commercial Weighted-average prepayment speeds 11.30 % Impact on fair value of 10% adverse change $ (8,525,000 ) Impact on fair value of 20% adverse change (16,390,000 ) Weighted-average OAS 10.95 % Impact on fair value of 10% adverse change $ (7,106,000 ) Impact on fair value of 20% adverse change (13,779,000 ) Weighted-average discount rate 18.00 % Impact on fair value of 10% adverse change $ (5,285,000 ) Impact on fair value of 20% adverse change (10,186,000 )

Goodwill and other intangible42

Goodwill and other intangible assets (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Finite-Lived Intangible Assets	Total amortizing intangible assets were comprised of the following: Gross Carrying Amount Accumulated Amortization Net Carrying Amount (In thousands) December 31, 2016 Core deposit $ 887,459 $ 789,988 $ 97,471 Other 177,268 177,084 184 Total $ 1,064,727 $ 967,072 $ 97,655 December 31, 2015 Core deposit $ 887,459 $ 750,624 $ 136,835 Other 177,268 173,835 3,433 Total $ 1,064,727 $ 924,459 $ 140,268
Estimated Amortization Expense in Future Years	Estimated amortization expense in future years for such intangible assets is as follows: (In thousands) Year ending December 31: 2017 $ 30,305 2018 23,462 2019 18,026 2020 13,323 2021 8,621 Later years 3,918 $ 97,655
Summary of Goodwill Assigned to Reportable Segments for Purposes of Testing for Impairment	A summary of goodwill assigned to each of the Company’s reportable segments as of December 31, 2016 and 2015 for purposes of testing for impairment is as follows. (In thousands) Business Banking $ 864,366 Commercial Banking 1,401,873 Commercial Real Estate 654,389 Discretionary Portfolio — Residential Mortgage Banking — Retail Banking 1,309,191 All Other 363,293 Total $ 4,593,112

Borrowings (Tables)

Borrowings (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Amounts and Interest Rates of Short-term Borrowings	The amounts and interest rates of short-term borrowings were as follows: Federal Funds Purchased and Repurchase Agreements Other Short-term Borrowings Total (Dollars in thousands) At December 31, 2016 Amount outstanding $ 163,442 — $ 163,442 Weighted-average interest rate 0.32 % — 0.32 % For the year ended December 31, 2016 Highest amount at a month-end $ 225,940 $ 1,974,013 Daily-average amount outstanding 203,853 689,969 $ 893,822 Weighted-average interest rate 0.28 % 0.44 % 0.41 % At December 31, 2015 Amount outstanding $ 150,546 $ 1,981,636 $ 2,132,182 Weighted-average interest rate 0.06 % 0.43 % 0.40 % For the year ended December 31, 2015 Highest amount at a month-end $ 202,951 $ 1,989,257 Daily-average amount outstanding 187,167 360,838 $ 548,005 Weighted-average interest rate 0.08 % 0.43 % 0.31 % At December 31, 2014 Amount outstanding $ 192,676 — $ 192,676 Weighted-average interest rate 0.07 % — 0.07 % For the year ended December 31, 2014 Highest amount at a month-end $ 280,350 — Daily-average amount outstanding 214,736 — $ 214,736 Weighted-average interest rate 0.05 % — 0.05 %
Lines of Credit Under Formal Agreements	At December 31, 2016, M&T Bank had lines of credit under formal agreements as follows: (In thousands) Outstanding borrowings $ 1,154,828 Unused 32,573,956
Long-term Borrowings	Long-term borrowings were as follows: December 31, 2016 2015 (In thousands) Senior notes of M&T Bank: Variable rate due 2016 $ — $ 300,000 Variable rate due 2017 550,000 550,000 1.25% due 2017 499,999 499,984 1.40% due 2017 749,946 749,851 1.45% due 2018 501,829 503,527 2.25% due 2019 649,012 648,628 2.30% due 2019 749,473 749,219 2.10% due 2020 749,735 749,650 2.90% due 2025 749,320 749,236 Advances from FHLB: Fixed rates 1,154,737 1,158,216 Agreements to repurchase securities 1,084,694 1,899,281 Subordinated notes of Wilmington Trust Corporation (a wholly owned subsidiary of M&T): 8.50% due 2018 207,651 213,417 Subordinated notes of M&T Bank: 6.625% due 2017 409,526 419,800 5.585% due 2020, variable rate commenced 2015 409,361 409,361 5.629% due 2021, variable rate commenced 2016 500,000 518,797 Junior subordinated debentures of M&T associated with preferred capital securities: Fixed rates: BSB Capital Trust I — 8.125%, due 2028 15,659 15,635 Provident Trust I — 8.29%, due 2028 26,293 25,817 Southern Financial Statutory Trust I — 10.60%, due 2030 6,620 6,583 Variable rates: First Maryland Capital I — due 2027 146,256 145,717 First Maryland Capital II — due 2027 147,954 147,291 Allfirst Asset Trust — due 2029 96,494 96,349 BSB Capital Trust III — due 2033 15,464 15,464 Provident Statutory Trust III — due 2033 53,834 53,244 Southern Financial Capital Trust III — due 2033 7,968 7,889 Other 12,010 20,902 $ 9,493,835 $ 10,653,858
Maturity of Long-term Borrowings	Long-term borrowings at December 31, 2016 mature as follows: (In thousands) Year ending December 31: 2017 $ 3,442,484 2018 714,358 2019 2,299,502 2020 1,269,939 2021 500,144 Later years 1,267,408 $ 9,493,835

Shareholders' equity (Tables)

Shareholders' equity (Tables)	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Issued and Outstanding Preferred Stock	Issued and outstanding preferred stock of M&T is presented below: December 31, 2016 December 31, 2015 Shares Issued and Outstanding Carrying value Shares Issued and Outstanding Carrying value (Dollars in thousands) Series A (a) Fixed Rate Cumulative Perpetual Preferred Stock, $1,000 liquidation preference per share 230,000 $ 230,000 230,000 $ 230,000 Series C (a) Fixed Rate Cumulative Perpetual Preferred Stock, $1,000 liquidation preference per share 151,500 $ 151,500 151,500 $ 151,500 Series D (b) Fixed Rate Non-cumulative Perpetual Preferred Stock, $10,000 liquidation preference per share — — 50,000 $ 500,000 Series E (c) Fixed-to-Floating Rate Non-cumulative Perpetual Preferred Stock, $1,000 liquidation preference per share 350,000 $ 350,000 350,000 $ 350,000 Series F (d) Fixed-to-Floating Rate Non-cumulative Perpetual Preferred Stock, $10,000 liquidation preference per share 50,000 $ 500,000 — — (a) Dividends, if declared, are paid at 6.375%. Warrants to purchase M&T common stock at $73.86 per share issued in connection with the Series A preferred stock expire in 2018 and totaled 631,794 and 719,175 at December 31, 2016 and 2015, respectively. (b) The shares were fully redeemed in December 2016, having received the approval of the Federal Reserve to redeem such shares after issuing the Series F preferred stock. (c) Dividends, if declared, are paid semi-annually at a rate of 6.45% through February 14, 2024 and thereafter will be paid quarterly at a rate of the three-month LIBOR plus 361 basis points (hundredths of one percent). The shares are redeemable in whole or in part on or after February 15, 2024. Notwithstanding M&T’s option to redeem the shares, if an event occurs such that the shares no longer qualify as Tier 1 capital, M&T may redeem all of the shares within 90 days following that occurrence. (d) Dividends, if declared, are paid semi-annually at a rate of 5.125% through October 31, 2026 and thereafter will be paid quarterly at a rate of the three-month LIBOR plus 352 basis points. The shares are redeemable in whole or in part on or after November 1, 2026. Notwithstanding M&T’s option to redeem the shares, if an event occurs such that the shares no longer qualify as Tier 1 capital, M&T may redeem all of the shares within 90 days following that occurrence.

Stock-based compensation plans

Stock-based compensation plans (Tables)	12 Months Ended
	Dec. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Restricted Stock and Restricted Stock Unit Activity	A summary of restricted stock and restricted stock unit activity follows: Restricted Stock Units Outstanding Weighted- Average Grant Price Restricted Stock Outstanding Weighted- Average Grant Price Unvested at January 1, 2016 968,498 $ 109.38 625,888 $ 103.82 Granted 348,297 111.38 218,341 110.31 Vested (570,509 ) 108.21 (324,981 ) 98.55 Cancelled (6,936 ) 110.90 (19,924 ) 108.15 Unvested at December 31, 2016 739,350 $ 111.21 499,324 $ 109.92
Summary of Stock Option Activity	A summary of stock option activity follows: Weighted-Average Stock Options Outstanding Exercise Price Life (In Years) Aggregate Intrinsic Value (In thousands) Outstanding at January 1, 2016 4,223,710 $ 126.65 Granted 200 110.18 Exercised (1,694,440 ) 106.68 Expired (934,879 ) 140.75 Outstanding at December 31, 2016 1,594,591 $ 139.60 1.5 $ 39,326 Exercisable at December 31, 2016 1,594,149 $ 139.60 1.5 $ 39,305

Pension plans and other postr46

Pension plans and other postretirement benefits (Tables)	12 Months Ended
	Dec. 31, 2016
Compensation And Retirement Disclosure [Abstract]
Net Periodic Pension Expense for Defined Benefit Plans	Net periodic pension expense for defined benefit plans consisted of the following: Year Ended December 31 2016 2015 2014 (In thousands) Service cost $ 25,037 $ 24,372 $ 20,520 Interest cost on benefit obligation 83,410 72,731 69,162 Expected return on plan assets (108,473 ) (96,155 ) (91,568 ) Amortization of prior service credit (3,228 ) (6,005 ) (6,552 ) Recognized net actuarial loss 30,145 44,825 14,494 Net periodic pension expense $ 26,891 $ 39,768 $ 6,056 Net other postretirement benefits expense for defined benefit plans consisted of the following: Year Ended December 31 2016 2015 2014 (In thousands) Service cost $ 1,595 $ 914 $ 605 Interest cost on benefit obligation 4,971 2,995 2,778 Amortization of prior service credit (1,359 ) (1,359 ) (1,359 ) Recognized net actuarial loss 60 106 — Net other postretirement benefits expense $ 5,267 $ 2,656 $ 2,024
Data Relating to Funding Position of Defined Benefit Plans	Data relating to the funding position of the defined benefit plans were as follows: Pension Benefits Other Postretirement Benefits 2016 2015 2016 2015 (In thousands) Change in benefit obligation: Benefit obligation at beginning of year $ 2,004,531 $ 1,813,409 $ 121,497 $ 67,502 Service cost 25,037 24,372 1,595 914 Interest cost 83,410 72,731 4,971 2,995 Plan participants’ contributions — — 3,085 2,619 Amendments and curtailments (28,308 ) — — — Actuarial (gain) loss 4,827 (83,593 ) (10,553 ) (2,431 ) Business combinations — 247,340 — 56,539 Medicare Part D reimbursement — — 592 420 Benefits paid (82,339 ) (69,728 ) (11,265 ) (7,061 ) Benefit obligation at end of year 2,007,158 2,004,531 109,922 121,497 Change in plan assets: Fair value of plan assets at beginning of year 1,625,134 1,505,661 — — Actual return on plan assets 88,564 (14,069 ) — — Employer contributions 10,772 8,367 7,588 4,022 Plan participants’ contributions — — 3,085 2,619 Business combinations — 194,903 — — Medicare Part D reimbursement — — 592 420 Benefits paid (82,339 ) (69,728 ) (11,265 ) (7,061 ) Fair value of plan assets at end of year 1,642,131 1,625,134 — — Funded status $ (365,027 ) $ (379,397 ) $ (109,922 ) $ (121,497 ) Accrued liabilities recognized in the consolidated balance sheet $ (365,027 ) $ (379,397 ) $ (109,922 ) $ (121,497 ) Amounts recognized in accumulated other comprehensive income (“AOCI”) were: Net loss (gain) $ 460,562 $ 494,279 $ (6,413 ) $ 4,200 Net prior service cost (credit) 3,505 277 (7,737 ) (9,096 ) Pre-tax adjustment to AOCI 464,067 494,556 (14,150 ) (4,896 ) Taxes (182,611 ) (194,608 ) 5,568 1,927 Net adjustment to AOCI $ 281,456 $ 299,948 $ (8,582 ) $ (2,969 )
Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income	The table below reflects the changes in plan assets and benefit obligations recognized in other comprehensive income related to the Company’s postretirement benefit plans. Pension Plans Other Postretirement Benefit Plans Total (In thousands) 2016 Net loss (gain) $ 24,736 $ (10,553 ) $ 14,183 Amendments and curtailments (28,308 ) — (28,308 ) Amortization of prior service credit 3,228 1,359 4,587 Amortization of actuarial loss (30,145 ) (60 ) (30,205 ) Total recognized in other comprehensive income, pre-tax $ (30,489 ) $ (9,254 ) $ (39,743 ) 2015 Net loss (gain) $ 26,631 $ (2,431 ) $ 24,200 Amortization of prior service credit 6,005 1,359 7,364 Amortization of actuarial loss (44,825 ) (106 ) (44,931 ) Total recognized in other comprehensive income, pre-tax $ (12,189 ) $ (1,178 ) $ (13,367 )
Amortization of Amounts in Accumulated Other Comprehensive Income Expected to be Recognized as Components of Net Periodic Benefit Expense	The following table reflects the amortization of amounts in accumulated other comprehensive income expected to be recognized as components of net periodic benefit expense during 2017: Pension Plans Other Postretirement Benefit Plans (In thousands) Amortization of net prior service cost (credit) $ 557 $ (1,359 ) Amortization of net loss (gain) 27,196 (44 )
Assumed Weighted-Average Rates Used to Determine Benefit Obligations	The assumed weighted-average rates used to determine benefit obligations at December 31 were: Pension Benefits Other Postretirement Benefits 2016 2015 2016 2015 Discount rate 4.00 % 4.25 % 4.00 % 4.25 % Rate of increase in future compensation levels 4.39 % 4.37 % — —
Assumed Weighted-Average Rates Used to Determine Net Benefit Expense	The assumed weighted-average rates used to determine net benefit expense for the years ended December 31 were: Pension Benefits Other Postretirement Benefits 2016 2015 2014 2016 2015 2014 Discount rate 4.25 % 4.00 % 4.75 % 4.25 % 4.00 % 4.75 % Long-term rate of return on plan assets 6.50 % 6.50 % 6.50 % — — — Rate of increase in future compensation levels 4.37 % 4.39 % 4.42 % — — —
Effects on One-Percentage Point Change in Assumed Health Care Cost Trend Rates	A one-percentage point change in assumed health care cost trend rates would have had the following effects: +1% -1% (In thousands) Increase (decrease) in: Service and interest cost $ 106 $ (87 ) Accumulated postretirement benefit obligation 1,548 (1,400 )
Fair Values of Company's Pension Plan Assets by Asset Category	The fair values of the Company’s pension plan assets at December 31, 2016, by asset category, were as follows: Fair Value Measurement of Plan Assets At December 31, 2016 Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Asset category: Money-market funds $ 39,556 $ 35,562 $ 3,994 $ — Equity securities: M&T 164,474 164,474 — — Domestic(a) 200,595 200,595 — — International(b) 14,364 14,364 — — Mutual funds: Domestic(a) 250,472 250,472 — — International(b) 290,172 290,172 — — 920,077 920,077 — — Debt securities: Corporate(c) 104,909 — 104,909 — Government 121,869 — 121,869 — International 13,073 — 13,073 — Mutual funds: Domestic(d) 205,847 205,847 — — 445,698 205,847 239,851 — Other: Diversified mutual fund 92,691 92,691 — — Real estate partnerships 3,112 768 — 2,344 Private equity 21,924 — — 21,924 Hedge funds 106,250 85,270 — 20,980 Guaranteed deposit fund 10,992 — — 10,992 234,969 178,729 — 56,240 Total(e) $ 1,640,300 $ 1,340,215 $ 243,845 $ 56,240 The fair values of the Company’s pension plan assets at December 31, 2015, by asset category, were as follows: Fair Value Measurement of Plan Assets At December 31, 2015 Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Asset category: Money-market funds $ 69,634 $ 37,958 $ 31,676 $ — Equity securities: M&T 148,800 148,800 — — Domestic(a) 106,993 106,993 — — International(b) 9,433 9,433 — — Mutual funds: Domestic(a) 445,663 445,663 — — International(b) 348,869 348,869 — — 1,059,758 1,059,758 — — Debt securities: Corporate(c) 105,499 — 105,499 — Government 120,346 — 120,346 — International 7,492 — 7,492 — Mutual funds: Domestic(d) 51,028 51,028 — — 284,365 51,028 233,337 — Other: Diversified mutual fund 70,343 70,343 — — Real estate partnerships 2,787 — — 2,787 Private equity 5,603 — — 5,603 Hedge funds 119,549 81,861 — 37,688 Guaranteed deposit fund 11,596 — — 11,596 209,878 152,204 — 57,674 Total(e) $ 1,623,635 $ 1,300,948 $ 265,013 $ 57,674 (a) This category is comprised of equities of companies primarily within the mid-cap and large-cap sectors of the U.S. economy and range across diverse industries. (b) This category is comprised of equities in companies primarily within the mid-cap and large-cap sectors of international markets mainly in developed markets in Europe and the Pacific Rim. (c) This category represents investment grade bonds of U.S. issuers from diverse industries. (d) Approximately 75% of the mutual funds were invested in investment grade bonds and 25% in high-yielding bonds at December 31, 2016. Approximately 33% of the mutual funds were invested in investment grade bonds and 67% in high-yielding bonds at December 31, 2015. The holdings within the funds were spread across diverse industries. (e) Excludes dividends and interest receivable totaling $1,831,000 and $1,499,000 at December 31, 2016 and 2015, respectively.
Changes in Level 3 Pension Plan Assets Measured at Fair Value on Recurring Basis	The changes in Level 3 pension plan assets measured at estimated fair value on a recurring basis during the year ended December 31, 2016 were as follows: Balance – January 1, 2016 Purchases (Sales) Total Realized/ Unrealized Gains (Losses) Balance – December 31, 2016 (In thousands) Other Private real estate $ 2,787 $ (1,111 ) $ 668 $ 2,344 Private equity 5,603 17,177 (856 ) 21,924 Hedge funds 37,688 (16,337 ) (371 ) 20,980 Guaranteed deposit fund 11,596 (540 ) (64 ) 10,992 Total $ 57,674 $ (811 ) $ (623 ) $ 56,240
Defined Benefit Plan Estimated Future Benefit Payments	Estimated benefits expected to be paid in future years related to the Company’s defined benefit pension and other postretirement benefits plans are as follows: Pension Benefits Other Postretirement Benefits (In thousands) Year ending December 31: 2017 $ 81,927 $ 8,142 2018 85,715 8,220 2019 91,819 8,251 2020 96,465 8,259 2021 101,698 8,235 2022 through 2026 568,830 40,282

Income taxes (Tables)

Income taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Components of Income Tax Expense	The components of income tax expense were as follows: Year Ended December 31 2016 2015 2014 (In thousands) Current Federal $ 428,750 $ 130,349 $ 378,978 State and city 95,426 21,549 50,790 Total current 524,176 151,898 429,768 Deferred Federal 147,662 324,317 65,503 State and city 26,351 72,279 27,345 Total deferred 174,013 396,596 92,848 Amortization of investments in qualified affordable housing projects 45,095 46,531 53,383 Total income taxes applicable to pre-tax income $ 743,284 $ 595,025 $ 575,999
Schedule of Income Tax Expense Benefit Reconciliation	Total income taxes differed from the amount computed by applying the statutory federal income tax rate to pre-tax income as follows: Year Ended December 31 2016 2015 2014 (In thousands) Income taxes at statutory federal income tax rate $ 720,439 $ 586,142 $ 574,786 Increase (decrease) in taxes: Tax-exempt income (35,364 ) (33,102 ) (31,752 ) State and city income taxes, net of federal income tax effect 79,155 60,988 50,788 Qualified affordable housing project federal tax credits, net (15,091 ) (15,297 ) (14,827 ) Other (5,855 ) (3,706 ) (2,996 ) $ 743,284 $ 595,025 $ 575,999
Deferred Tax Assets (Liabilities)	Deferred tax assets (liabilities) were comprised of the following at December 31: 2016 2015 2014 (In thousands) Losses on loans and other assets $ 590,288 $ 637,955 $ 605,273 Retirement benefits 143,067 148,722 120,222 Postretirement and other employee benefits 52,512 55,962 34,052 Incentive and other compensation plans 36,616 60,337 36,450 Interest on loans 61,266 57,640 79,147 Stock-based compensation 52,181 72,090 64,017 Unrealized investment losses 10,741 — — Depreciation and amortization — — 3,527 Other 106,876 162,086 100,999 Gross deferred tax assets 1,053,547 1,194,792 1,043,687 Leasing transactions (266,268 ) (285,074 ) (280,596 ) Unrealized investment gains — (31,121 ) (82,065 ) Capitalized servicing rights (71,108 ) (59,171 ) (46,393 ) Depreciation and amortization (63,959 ) (56,731 ) — Other (87,200 ) (55,611 ) (66,939 ) Gross deferred tax liabilities (488,535 ) (487,708 ) (475,993 ) Net deferred tax asset $ 565,012 $ 707,084 $ 567,694
Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits follows: Federal, State and Local Tax Accrued Interest Unrecognized Income Tax Benefits (In thousands) Gross unrecognized tax benefits at January 1, 2014 $ 14,611 $ 14,696 $ 29,307 Increases as a result of tax positions taken during 2014 769 — 769 Increases as a result of tax positions taken in prior years — 453 453 Decreases as a result of settlements with taxing authorities (4,668 ) (11,280 ) (15,948 ) Gross unrecognized tax benefits at December 31, 2014 10,712 3,869 14,581 Increases as a result of tax positions taken during 2015 8,108 — 8,108 Increases as a result of tax positions taken in prior years — 807 807 Decreases as a result of settlements with taxing authorities (1,515 ) (274 ) (1,789 ) Unrealized tax benefits acquired in a business combination 7,232 3,567 10,799 Gross unrecognized tax benefits at December 31, 2015 24,537 7,969 32,506 Increases as a result of tax positions taken during 2016 12,237 — 12,237 Increases as a result of tax positions taken in prior years — 656 656 Decreases as a result of tax positions taken in prior years (885 ) (710 ) (1,595 ) Gross unrecognized tax benefits at December 31, 2016 $ 35,889 $ 7,915 43,804 Less: Federal, state and local income tax benefits (15,332 ) Net unrecognized tax benefits at December 31, 2016 that, if recognized, would impact the effective income tax rate $ 28,472

Earnings per common share (Tabl

Earnings per common share (Tables)	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Computations of Basic Earnings Per Common Share	The computations of basic earnings per common share follow: Year Ended December 31 2016 2015 2014 (In thousands, except per share) Income available to common shareholders: Net income $ 1,315,114 $ 1,079,667 $ 1,066,246 Less: Preferred stock dividends(a) (81,270 ) (81,270 ) (75,878 ) Net income available to common equity 1,233,844 998,397 990,368 Less: Income attributable to unvested stock-based compensation awards (10,385 ) (10,708 ) (11,837 ) Net income available to common shareholders $ 1,223,459 $ 987,689 $ 978,531 Weighted-average shares outstanding: Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards 158,121 138,285 132,532 Less: Unvested stock-based compensation awards (1,341 ) (1,482 ) (1,582 ) Weighted-average shares outstanding 156,780 136,803 130,950 Basic earnings per common share $ 7.80 $ 7.22 $ 7.47 (a) Including impact of not as yet declared cumulative dividends.
Computations of Diluted Earnings Per Common Share	The computations of diluted earnings per common share follow: Year Ended December 31 2016 2015 2014 (In thousands, except per share) Net income available to common equity $ 1,233,844 $ 998,397 $ 990,368 Less: Income attributable to unvested stock-based compensation awards (10,363 ) (10,673 ) (11,787 ) Net income available to common shareholders $ 1,223,481 $ 987,724 $ 978,581 Adjusted weighted-average shares outstanding: Common and unvested stock-based compensation awards 158,121 138,285 132,532 Less: Unvested stock-based compensation awards (1,341 ) (1,482 ) (1,582 ) Plus: Incremental shares from assumed conversion of stock-based compensation awards and warrants to purchase common stock 524 730 894 Adjusted weighted-average shares outstanding 157,304 137,533 131,844 Diluted earnings per common share $ 7.78 $ 7.18 $ 7.42

Comprehensive income (Tables)

Comprehensive income (Tables)	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Components of Other Comprehensive Income (Loss) and Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) to Net Income	The following tables display the components of other comprehensive income (loss) and amounts reclassified from accumulated other Investment Securities Defined Total With OTTI (a) All Other Benefit Plans Other Amount Before Tax Income Tax Net (In thousands) Balance — January 1, 2016 $ 16,359 $ 62,849 $ (489,660 ) $ (4,093 ) $ (414,545 ) $ 162,918 $ (251,627 ) Other comprehensive income before reclassifications: Unrealized holding gains (losses), net 30,366 (110,316 ) — — (79,950 ) 31,509 (48,441 ) Foreign currency translation adjustment — — — (4,020 ) (4,020 ) 1,406 (2,614 ) Current year benefit plans gains — — 14,125 — 14,125 (5,557 ) 8,568 Total other comprehensive income (loss) before reclassifications 30,366 (110,316 ) 14,125 (4,020 ) (69,845 ) 27,358 (42,487 ) Amounts reclassified from accumulated other comprehensive income that (increase) decrease net income: Amortization of unrealized holding losses on held-to- maturity ("HTM") securities — 3,996 — — 3,996 (b) (1,572 ) 2,424 Gains realized in net income — (30,314 ) — — (30,314 ) (c) 11,925 (18,389 ) Accretion of net gain on terminated cash flow hedges — — — (155 ) (155 ) (d) 61 (94 ) Amortization of prior service credit — — (4,587 ) — (4,587 ) (e) 1,805 (2,782 ) Amortization of actuarial losses — — 30,205 — 30,205 (e) (11,886 ) 18,319 Total reclassifications — (26,318 ) 25,618 (155 ) (855 ) 333 (522 ) Total gain (loss) during the period 30,366 (136,634 ) 39,743 (4,175 ) (70,700 ) 27,691 (43,009 ) Balance — December 31, 2016 $ 46,725 $ (73,785 ) $ (449,917 ) $ (8,268 ) $ (485,245 ) $ 190,609 $ (294,636 ) Investment Securities Defined Total With OTTI (a) All Other Benefit Plans Other Amount Before Tax Income Tax Net (In thousands) Balance — January 1, 2015 $ 7,438 $ 201,828 $ (503,027 ) $ (4,082 ) $ (297,843 ) $ 116,849 $ (180,994 ) Other comprehensive income before reclassifications: Unrealized holding gains (losses), net 8,921 (142,623 ) — — (133,702 ) 52,376 (81,326 ) Foreign currency translation adjustment — — — (1,323 ) (1,323 ) 398 (925 ) Gains on cash flow hedges — — — 1,453 1,453 (572 ) 881 Current year benefit plans losses — — (24,200 ) — (24,200 ) 8,612 (15,588 ) Total other comprehensive income (loss) before reclassifications 8,921 (142,623 ) (24,200 ) 130 (157,772 ) 60,814 (96,958 ) Amounts reclassified from accumulated other comprehensive income that (increase) decrease net income: Amortization of unrealized holding losses on HTM securities — 3,514 — — 3,514 (b) (1,383 ) 2,131 Losses realized in net income — 130 — — 130 (c) (49 ) 81 Accretion of net gain on terminated cash flow hedges — — — (141 ) (141 ) (d) 56 (85 ) Amortization of prior service credit — — (7,364 ) — (7,364 ) (e) 2,620 (4,744 ) Amortization of actuarial losses — — 44,931 — 44,931 (e) (15,989 ) 28,942 Total reclassifications — 3,644 37,567 (141 ) 41,070 (14,745 ) 26,325 Total gain (loss) during the period 8,921 (138,979 ) 13,367 (11 ) (116,702 ) 46,069 (70,633 ) Balance — December 31, 2015 $ 16,359 $ 62,849 $ (489,660 ) $ (4,093 ) $ (414,545 ) $ 162,918 $ (251,627 ) Investment Securities Defined Total With OTTI (a) All Other Benefit Plans Other Amount Before Tax Income Tax Net (In thousands) Balance — January 1, 2014 $ 37,255 $ 18,450 $ (161,617 ) $ 115 $ (105,797 ) $ 41,638 $ (64,159 ) Other comprehensive income before reclassifications: Unrealized holding gains (losses), net (29,818 ) 180,005 — — 150,187 (58,962 ) 91,225 Foreign currency translation adjustment — — — (4,039 ) (4,039 ) 1,432 (2,607 ) Unrealized losses on cash flow hedges — — — (165 ) (165 ) 65 (100 ) Current year benefit plans losses — — (347,993 ) — (347,993 ) 136,587 (211,406 ) Total other comprehensive income (loss) before reclassifications (29,818 ) 180,005 (347,993 ) (4,204 ) (202,010 ) 79,122 (122,888 ) Amounts reclassified from accumulated other comprehensive income that (increase) decrease net income: Amortization of unrealized holding losses on HTM securities 1 3,373 — — 3,374 (b) (1,324 ) 2,050 Amortization of losses on terminated cash flow hedges — — — 7 7 (d) (3 ) 4 Amortization of prior service credit — — (7,911 ) — (7,911 ) (e) 3,105 (4,806 ) Amortization of actuarial losses — — 14,494 — 14,494 (e) (5,689 ) 8,805 Total reclassifications 1 3,373 6,583 7 9,964 (3,911 ) 6,053 Total gain (loss) during the period (29,817 ) 183,378 (341,410 ) (4,197 ) (192,046 ) 75,211 (116,835 ) Balance — December 31, 2014 $ 7,438 $ 201,828 $ (503,027 ) $ (4,082 ) $ (297,843 ) $ 116,849 $ (180,994 ) (a) Other-than-temporary impairment. (b) Included in interest income. (c) Included in gain (loss) on bank investment securities. (d) Included in interest expense. (e) Included in salaries and employee benefits expense.
Accumulated Other Comprehensive Income (Loss), Net	Accumulated other comprehensive income (loss), net consisted of the following: Investment securities Defined Benefit With All Other Plans Other Total (In thousands) Balance at January 1, 2014 $ 22,632 $ 11,294 $ (98,182 ) $ 97 $ (64,159 ) Net gain (loss) during 2014 (18,114 ) 111,389 (207,407 ) (2,703 ) (116,835 ) Balance at December 31, 2014 4,518 122,683 (305,589 ) (2,606 ) (180,994 ) Net gain (loss) during 2015 5,403 (84,517 ) 8,610 (129 ) (70,633 ) Balance at December 31, 2015 9,921 38,166 (296,979 ) (2,735 ) (251,627 ) Net gain (loss) during 2016 18,417 (82,823 ) 24,105 (2,708 ) (43,009 ) Balance at December 31, 2016 $ 28,338 $ (44,657 ) $ (272,874 ) $ (5,443 ) $ (294,636 )

Other income and other expense

Other income and other expense (Tables)	12 Months Ended
	Dec. 31, 2016
Other Income And Expenses [Abstract]
Other Income and Other Expense	The following items, which exceeded 1% of total interest income and other income in the respective period, were included in either “other revenues from operations” or “other costs of operations” in the consolidated statement of income: Year Ended December 31 2016 2015 2014 (In thousands) Other income: Credit-related fee income $ 70,424 $ 81,558 $ 72,454 Letter of credit fees 52,724 56,708 Bank owned life insurance 52,984 50,004 Other expense: Professional services 268,060 267,540 324,460 Amortization of capitalized servicing rights 49,906 68,410

Derivative financial instrume51

Derivative financial instruments (Tables)	12 Months Ended
	Dec. 31, 2016
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Information about Interest Rate Swap Agreements	Information about interest rate swap agreements entered into for interest rate risk management purposes summarized by type of financial instrument the swap agreements were intended to hedge follows: Notional Average Weighted- Average Rate Estimated Fair Amount Maturity Fixed Variable Value Gain (In thousands) (In years) (In thousands) December 31, 2016 Fair value hedges: Fixed rate long-term borrowings(a) $ 900,000 1.1 3.75 % 2.08 % $ 11,892 December 31, 2015 Fair value hedges: Fixed rate long-term borrowings(a) $ 1,400,000 1.7 4.42 % 1.39 % $ 43,892 (a) Under the terms of these agreements, the Company receives settlement amounts at a fixed rate and pays at a variable rate.
Notional Amount of Interest Rate Swap Agreements Outstanding Maturity	The notional amount of interest rate swap agreements entered into for risk management purposes that were outstanding at December 31, 2016 mature as follows: (In thousands) Year ending December 31: 2017 $ 400,000 2018 500,000 $ 900,000
Information about Fair Values of Derivative Instruments in Consolidated Balance Sheet	Information about the fair values of derivative instruments in the Company’s consolidated balance sheet and consolidated statement of income follows: Asset Derivatives Liability Derivatives Fair Value Fair Value December 31 December 31 2016 2015 2016 2015 (In thousands) Derivatives designated and qualifying as hedging instruments Fair value hedges: Interest rate swap agreements(a) $ 11,892 $ 43,892 $ — $ — Commitments to sell real estate loans(a) 33,189 1,844 1,347 656 45,081 45,736 1,347 656 Derivatives not designated and qualifying as hedging instruments Mortgage-related commitments to originate real estate loans for sale(a) 8,060 10,282 735 403 Commitments to sell real estate loans(a) 5,210 533 399 846 Trading: Interest rate contracts(b) 228,810 203,517 167,737 153,723 Foreign exchange and other option and futures contracts(b) 7,908 8,569 6,639 7,022 249,988 222,901 175,510 161,994 Total derivatives $ 295,069 $ 268,637 $ 176,857 $ 162,650 (a) Asset derivatives are reported in other assets and liability derivatives are reported in other liabilities. (b) Asset derivatives are reported in trading account assets and liability derivatives are reported in other liabilities.
Information about Fair Values of Derivative Instruments in Consolidated Statement of Income	Amount of Gain (Loss) Recognized Year Ended December 31, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 Derivative Hedged Item Derivative Hedged Item Derivative Hedged Item (In thousands) Derivatives in fair value hedging relationships Interest rate swap agreements: Fixed rate long-term borrowings(a) $ (32,000 ) 30,906 $ (29,359 ) 28,719 $ (29,624 ) 28,870 Derivatives not designated as hedging instruments Trading: Interest rate contracts(b) $ 14,042 $ 10,755 $ 3,398 Foreign exchange and other option and futures contracts(b) 7,665 9,337 7,670 Total $ 21,707 $ 20,092 $ 11,068 (a) Reported as other revenues from operations. (b) Reported as trading account and foreign exchange gains.

Fair value measurements (Tables

Fair value measurements (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Estimated Fair Value on Recurring Basis	The following tables present assets and liabilities at December 31, 2016 and 2015 measured at estimated fair value on a recurring basis: Fair Value Measurements at December 31, 2016 Level 1 (a) Level 2 (a) Level 3 (In thousands) Trading account assets $ 323,867 $ 46,135 $ 277,732 $ — Investment securities available for sale: U.S. Treasury and federal agencies 1,902,544 — 1,902,544 — Obligations of states and political subdivisions 3,641 — 3,641 — Mortgage-backed securities: Government issued or guaranteed 10,954,861 — 10,954,861 — Privately issued 44 — — 44 Other debt securities 118,516 — 118,516 — Equity securities 352,466 301,711 50,755 — 13,332,072 301,711 13,030,317 44 Real estate loans held for sale 1,056,180 — 1,056,180 — Other assets(b) 58,351 — 50,291 8,060 Total assets $ 14,770,470 $ 347,846 $ 14,414,520 $ 8,104 Trading account liabilities $ 174,376 $ — $ 174,376 $ — Other liabilities(b) 2,481 — 1,746 735 Total liabilities $ 176,857 $ — $ 176,122 $ 735 Fair Value Measurements at December 31, 2015 Level 1(a) Level 2(a) Level 3 (In thousands) Trading account assets $ 273,783 $ 56,763 $ 217,020 $ — Investment securities available for sale: U.S. Treasury and federal agencies 299,997 — 299,997 — Obligations of states and political subdivisions 6,028 — 6,028 — Mortgage-backed securities: Government issued or guaranteed 11,686,628 — 11,686,628 — Privately issued 74 — — 74 Collateralized debt obligations 47,393 — — 47,393 Other debt securities 118,880 — 118,880 — Equity securities 83,671 65,178 18,493 — 12,242,671 65,178 12,130,026 47,467 Real estate loans held for sale 392,036 — 392,036 — Other assets(b) 56,551 — 46,269 10,282 Total assets $ 12,965,041 $ 121,941 $ 12,785,351 $ 57,749 Trading account liabilities $ 160,745 $ — $ 160,745 $ — Other liabilities(b) 1,905 — 1,502 403 Total liabilities $ 162,650 $ — $ 162,247 $ 403 (a) There were no significant transfers between Level 1 and Level 2 of the fair value hierarchy during the years ended December 31, 2016 and 2015. (b) Comprised predominantly of interest rate swap agreements used for interest rate risk management (Level 2), commitments to sell real estate loans (Level 2) and commitments to originate real estate loans to be held for sale (Level 3).
Changes in Level 3 Assets and Liabilities Measured at Estimated Fair Value on Recurring Basis	The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the year ended December 31, 2016 were as follows: Investment Securities Available for S Privately Issued Mortgage-Backed Securities Collateralized Debt Obligations Other Assets and Other Liabilities (In thousands) Balance - January 1, 2016 $ 74 $ 47,393 $ 9,879 Total gains (losses) realized/unrealized: Included in earnings — 30,041 (c) 110,937 (b) Included in other comprehensive income — (18,268 ) (d) — Sales — (58,296 ) — Settlements (30 ) (870 ) — Transfers out of Level 3(a) — — (113,491 ) (e) Balance — December 31, 2016 $ 44 $ — $ 7,325 Changes in unrealized gains included in earnings related to assets still held at December 31, 2016 $ — $ — $ 7,256 (b) The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the year ended December 31, 2015 were as follows: Investment Securities Available for S Privately Issued Mortgage-Backed Securities Collateralized Debt Obligations Other Assets and Other Liabilities (In thousands) Balance — January 1, 2015 $ 103 $ 50,316 $ 17,347 Total gains realized/unrealized: Included in earnings — — 87,061 (b) Included in other comprehensive income — 3,254 (d) — Settlements (29 ) (6,177 ) — Transfers out of Level 3(a) — — (94,529 ) (e) Balance — December 31, 2015 $ 74 $ 47,393 $ 9,879 Changes in unrealized gains included in earnings related to assets still held at December 31, 2015 $ — $ — $ 8,850 (b) The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the year ended December 31, 2014 were as follows: Investment Securities Available for S Privately Issued Mortgage-Backed Securities Collateralized Debt Obligations Other Assets and Other Liabilities (In thousands) Balance – January 1, 2014 $ 1,850 $ 63,083 $ 3,941 Total gains realized/unrealized: Included in earnings — — 83,417 (b) Included in other comprehensive income 271 (d) 8,209 (d) — Settlements (2,018 ) (20,976 ) — Transfers out of Level 3(a) — — (70,011 ) (e) Balance – December 31, 2014 $ 103 $ 50,316 $ 17,347 Changes in unrealized gains included in earnings related to assets still held at December 31, 2014 $ — $ — $ 18,196 (b) (a ) The Company’s policy for transfers between fair value levels is to recognize the transfer as of the actual date of the event or change in circumstances that caused the transfer. (b) Reported as mortgage banking revenues in the consolidated statement of income and includes the fair value of commitment issuances and expirations. (c) Reported as gain (loss) on bank investment securities in the consolidated statement of income. (d) Reported as net unrealized gains (losses) on investment securities in the consolidated statement of comprehensive income. (e) Transfers out of Level 3 consist of interest rate locks transferred to closed loans.
Quantitative Information Related to Significant Unobservable Inputs	The following tables present quantitative information about significant unobservable inputs used in the fair value measurements for Level 3 assets and liabilities at December 31, 2016 and 2015: Fair Value at December 31, 2016 Valuation Technique Unobservable Inputs/Assumptions Range (Weighted- Average) (In thousands) Recurring fair value measurements: Privately issued mortgage-backed securities $ 44 Two independent pricing quotes — — Net other assets (liabilities)(a) 7,325 Discounted cash flow Commitment expirations 0%-77% (30%) Fair Value at December 31, 2015 Valuation Technique Unobservable Inputs/Assumptions Range (Weighted- Average) (In thousands) Recurring fair value measurements: Privately issued mortgage-backed securities $ 74 Two independent pricing quotes — — Collateralized debt obligations 47,393 Discounted cash flow Probability of default 10%-56% (31%) Loss severity 100% Net other assets (liabilities)(a) 9,879 Discounted cash flow Commitment expirations 0%-60% (39%) (a) Other Level 3 assets (liabilities) consist of commitments to originate real estate loans.
Carrying Amounts and Estimated Fair Value for Financial Instrument Assets (Liabilities)	The carrying amounts and estimated fair value for financial instrument assets (liabilities) are presented in the following table: December 31, 2016 Carrying Amount Estimated Fair Value Level 1 Level 2 Level 3 (In thousands) Financial assets: Cash and cash equivalents $ 1,320,549 1,320,549 1,249,654 70,895 — Interest-bearing deposits at banks 5,000,638 5,000,638 — 5,000,638 — Trading account assets 323,867 323,867 46,135 277,732 — Investment securities 16,250,468 16,244,412 301,711 15,821,176 121,525 Loans and leases: Commercial loans and leases 22,610,047 22,239,428 — — 22,239,428 Commercial real estate loans 33,506,394 33,129,428 — 642,590 32,486,838 Residential real estate loans 22,590,912 22,638,167 — 4,912,488 17,725,679 Consumer loans 12,146,063 12,061,590 — — 12,061,590 Allowance for credit losses (988,997 ) — — — — Loans and leases, net 89,864,419 90,068,613 — 5,555,078 84,513,535 Accrued interest receivable 308,805 308,805 — 308,805 — Financial liabilities: Noninterest-bearing deposits $ (32,813,896 ) (32,813,896 ) — (32,813,896 ) — Savings and interest-checking deposits (52,346,207 ) (52,346,207 ) — (52,346,207 ) — Time deposits (10,131,846 ) (10,222,585 ) — (10,222,585 ) — Deposits at Cayman Islands office (201,927 ) (201,927 ) — (201,927 ) — Short-term borrowings (163,442 ) (163,442 ) — (163,442 ) — Long-term borrowings (9,493,835 ) (9,473,844 ) — (9,473,844 ) — Accrued interest payable (75,172 ) (75,172 ) — (75,172 ) — Trading account liabilities (174,376 ) (174,376 ) — (174,376 ) — Other financial instruments: Commitments to originate real estate loans for sale $ 7,325 7,325 — — 7,325 Commitments to sell real estate loans 36,653 36,653 — 36,653 — Other credit-related commitments (136,295 ) (136,295 ) — — (136,295 ) Interest rate swap agreements used for interest rate risk management 11,892 11,892 — 11,892 — December 31, 2015 Carrying Amount Estimated Fair Value Level 1 Level 2 Level 3 (In thousands) Financial assets: Cash and cash equivalents $ 1,368,040 1,368,040 1,276,678 91,362 — Interest-bearing deposits at banks 7,594,350 7,594,350 — 7,594,350 — Trading account assets 273,783 273,783 56,763 217,020 — Investment securities 15,656,439 15,660,877 65,178 15,406,404 189,295 Loans and leases: Commercial loans and leases 20,422,338 20,146,201 — — 20,146,201 Commercial real estate loans 29,197,311 29,044,244 — 38,774 29,005,470 Residential real estate loans 26,270,103 26,267,771 — 4,727,816 21,539,955 Consumer loans 11,599,747 11,550,270 — — 11,550,270 Allowance for credit losses (955,992 ) — — — — Loans and leases, net 86,533,507 87,008,486 — 4,766,590 82,241,896 Accrued interest receivable 306,496 306,496 — 306,496 — Financial liabilities: Noninterest-bearing deposits $ (29,110,635 ) (29,110,635 ) — (29,110,635 ) — Savings and interest-checking deposits (49,566,644 ) (49,566,644 ) — (49,566,644 ) — Time deposits (13,110,392 ) (13,135,042 ) — (13,135,042 ) — Deposits at Cayman Islands office (170,170 ) (170,170 ) — (170,170 ) — Short-term borrowings (2,132,182 ) (2,132,182 ) — (2,132,182 ) — Long-term borrowings (10,653,858 ) (10,639,556 ) — (10,639,556 ) — Accrued interest payable (85,145 ) (85,145 ) — (85,145 ) — Trading account liabilities (160,745 ) (160,745 ) — (160,745 ) — Other financial instruments: Commitments to originate real estate loans for sale $ 9,879 9,879 — — 9,879 Commitments to sell real estate loans 875 875 — 875 — Other credit-related commitments (122,334 ) (122,334 ) — — (122,334 ) Interest rate swap agreements used for interest rate risk management 43,892 43,892 — 43,892 —

Commitments and contingencies (

Commitments and contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments And Contingencies Disclosure [Abstract]
Company's Significant Commitments	The following table presents the Company’s significant commitments. Certain of these commitments are not included in the Company’s consolidated balance sheet. December 31 2016 2015 (In thousands) Commitments to extend credit Home equity lines of credit $ 5,499,609 $ 5,631,680 Commercial real estate loans to be sold 70,100 57,597 Other commercial real estate 6,451,709 5,949,933 Residential real estate loans to be sold 478,950 488,621 Other residential real estate 232,721 212,619 Commercial and other 12,298,473 11,802,850 Standby letters of credit 2,987,091 3,330,013 Commercial letters of credit 44,723 55,559 Financial guarantees and indemnification contracts 3,043,580 2,794,322 Commitments to sell real estate loans 1,489,237 782,885
Minimum Lease Payments Under Noncancelable Operating Leases	Minimum lease payments under noncancelable operating leases are summarized in the following table: (In thousands) Year ending December 31: 2017 $ 99,847 2018 94,448 2019 74,814 2020 58,216 2021 44,508 Later years 94,825 $ 466,658

Segment information (Tables)

Segment information (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Information about Company's Segments	Information about the Company’s segments is presented in the accompanying table. Income statement amounts are in thousands of dollars. Balance sheet amounts are in millions of dollars. For the Years Ended December 31, 2016, 2015 and 2014 Business Banking Commercial Banking Commercial Real Estate Discretionary Portfolio 2016 2015 2014 2016 2015 2014 2016 2015 2014 2016 2015 2014 Net interest income(a) $ 354,333 $ 338,855 $ 345,773 $ 785,874 $ 753,604 $ 746,344 $ 608,385 $ 577,922 $ 555,358 $ 345,926 $ 97,626 $ 74,204 Noninterest income 108,783 108,195 105,149 274,923 290,142 254,295 179,706 142,948 125,087 26,075 28,114 27,464 463,116 447,050 450,922 1,060,797 1,043,746 1,000,639 788,091 720,870 680,445 372,001 125,740 101,668 Provision for credit losses 12,709 15,513 18,883 34,903 25,089 33,213 (3,447 ) (8,003 ) (7,339 ) 32,925 7,599 16,547 Amortization of core deposit and other intangible assets — — — — — — — — — — — — Depreciation and other amortization 404 407 405 520 566 588 20,120 19,247 16,300 472 679 891 Other noninterest expense 292,124 264,163 263,734 327,616 288,303 284,091 204,965 169,688 169,039 95,300 49,839 33,522 Income (loss) before taxes 157,879 166,967 167,900 697,758 729,788 682,747 566,453 539,938 502,445 243,304 67,623 50,708 Income tax expense (benefit) 64,533 68,209 68,630 286,062 298,758 279,819 216,095 199,297 186,485 79,766 8,351 2,365 Net income (loss) $ 93,346 $ 98,758 $ 99,270 $ 411,696 $ 431,030 $ 402,928 $ 350,358 $ 340,641 $ 315,960 $ 163,538 $ 59,272 $ 48,343 Average total assets (in millions) $ 5,456 $ 5,339 $ 5,278 $ 25,592 $ 24,143 $ 22,860 $ 21,131 $ 18,827 $ 17,405 $ 40,867 $ 26,648 $ 20,798 Capital expenditures (in millions) $ — $ — $ 2 $ — $ — $ — $ — $ — $ — $ — $ — $ — For the Years Ended December 31, 2016, 2015 and 2014 Residential Mortgage Banking Retail Banking All Other Total 2016 2015 2014 2016 2015 2014 2016 2015 2014 2016 2015 2014 Net interest income(a) $ 70,655 $ 63,939 $ 67,482 $ 1,074,125 $ 917,041 $ 908,828 $ 230,589 $ 93,600 $ (21,543 ) $ 3,469,887 $ 2,842,587 $ 2,676,446 Noninterest income 342,858 336,099 331,366 323,176 324,953 336,042 570,475 594,586 599,870 1,825,996 1,825,037 1,779,273 413,513 400,038 398,848 1,397,301 1,241,994 1,244,870 801,064 688,186 578,327 5,295,883 4,667,624 4,455,719 Provision for credit losses (3,617 ) (5,225 ) (1,508 ) 120,437 72,953 77,158 (3,910 ) 62,074 (12,954 ) 190,000 170,000 124,000 Amortization of core deposit and other intangible assets — — — — — — 42,613 26,424 33,824 42,613 26,424 33,824 Depreciation and other amortization 30,264 27,883 47,086 37,657 35,291 37,788 68,541 64,852 61,848 157,978 148,925 164,906 Other noninterest expense 258,141 233,651 216,556 776,123 682,594 668,919 892,625 959,345 854,883 2,846,894 2,647,583 2,490,744 Income (loss) before taxes 128,725 143,729 136,714 463,084 451,156 461,005 (198,805 ) (424,509 ) (359,274 ) 2,058,398 1,674,692 1,642,245 Income tax expense (benefit) 49,047 55,151 52,172 188,438 183,638 187,647 (140,657 ) (218,379 ) (201,119 ) 743,284 595,025 575,999 Net income (loss) $ 79,678 $ 88,578 $ 84,542 $ 274,646 $ 267,518 $ 273,358 $ (58,148 ) $ (206,130 ) $ (158,155 ) $ 1,315,114 $ 1,079,667 $ 1,066,246 Average total assets (in millions) $ 2,569 $ 2,918 $ 3,076 $ 11,840 $ 11,035 $ 10,449 $ 16,885 $ 12,870 $ 12,277 $ 124,340 $ 101,780 $ 92,143 Capital expenditures (in millions) $ — $ — $ — $ 46 $ 14 $ 14 $ 62 $ 68 $ 57 $ 108 $ 82 $ 73 (a) Net interest income is the difference between actual taxable-equivalent interest earned on assets and interest paid on liabilities by a segment and a funding charge (credit) based on the Company’s internal funds transfer pricing methodology. Segments are charged a cost to fund any assets (e.g. loans) and are paid a funding credit for any funds provided (e.g. deposits). The taxable-equivalent adjustment aggregated $26,962,000 in 2016, $24,463,000 in 2015 and $23,642,000 in 2014 and is eliminated in “All Other” net interest income and income tax expense (benefit).
Intersegment Activity Eliminated in Arriving at Consolidated Totals was Included in "All Other" Category	The amount of intersegment activity eliminated in arriving at consolidated totals was included in the “All Other” category as follows: Year Ended December 31 2016 2015 2014 (In thousands) Revenues $ (48,625 ) $ (48,972 ) $ (49,800 ) Expenses (40,422 ) (13,332 ) (12,014 ) Income taxes (benefit) (3,338 ) (14,503 ) (15,375 ) Net income (loss) (4,865 ) (21,137 ) (22,411 )

Regulatory matters (Tables)

Regulatory matters (Tables)	12 Months Ended
	Dec. 31, 2016
Banking And Thrift [Abstract]
Summary of Required Minimum and Well Capitalized Capital Ratios	Pursuant to the rules in effect as of December 31, 2016, the required minimum and well capitalized capital ratios are as follows: Well Minimum Capitalized ● Common equity Tier 1 ("CET1") to risk-weighted assets 4.5 % 6.5 % ● Tier 1 capital to risk-weighted assets 6.0 % 8.0 % ● Total capital to risk-weighted assets 8.0 % 10.0 % ● Leverage — Tier 1 capital to average total assets, as defined 4.0 % 5.0 %
Capital Ratios and Amounts of Company and its Banking Subsidiaries	The capital ratios and amounts of the Company and its banking subsidiaries as of December 31, 2016 and 2015 are presented below: M&T (Consolidated) M&T Bank Wilmington Trust, N.A. (Dollars in thousands) December 31, 2016: Common equity Tier 1 capital Amount $ 10,849,642 $ 10,115,688 $ 496,801 Ratio(a) 10.70 % 10.02 % 57.08 % Minimum required amount(b) 5,195,288 5,175,310 44,607 Tier 1 capital Amount 12,083,948 10,115,688 496,801 Ratio(a) 11.92 % 10.02 % 57.08 % Minimum required amount(b) 6,715,859 6,690,035 57,662 Total capital Amount 14,282,492 11,812,114 501,111 Ratio(a) 14.09 % 11.70 % 57.57 % Minimum required amount(b) 8,743,289 8,709,668 75,070 Leverage Amount 12,083,948 10,115,688 496,801 Ratio(c) 9.99 % 8.41 % 15.31 % Minimum required amount(b) 4,836,901 4,812,685 129,774 December 31, 2015: Common equity Tier 1 capital Amount $ 10,485,426 $ 10,680,827 $ 476,106 Ratio(a) 11.08 % 11.33 % 86.87 % Minimum required amount(b) 4,259,977 4,242,817 24,664 Tier 1 capital Amount 12,008,232 10,680,827 476,106 Ratio(a) 12.68 % 11.33 % 86.87 % Minimum required amount(b) 5,679,969 5,657,089 32,886 Total capital Amount 14,128,454 12,589,917 480,415 Ratio(a) 14.92 % 13.35 % 87.65 % Minimum required amount(b) 7,573,292 7,542,786 43,848 Leverage Amount 12,008,232 10,680,827 476,106 Ratio(c) 10.89 % 9.75 % 22.38 % Minimum required amount(b) 4,408,971 4,381,617 85,082 (a) The ratio of capital to risk-weighted assets, as defined by regulation. (b) Minimum amount of capital to be considered adequately capitalized, as defined by regulation and including transition portion of the capital conservation buffer for 2016. (c) The ratio of capital to average assets, as defined by regulation.

Parent company financial stat56

Parent company financial statements (Tables)	12 Months Ended
	Dec. 31, 2016
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Condensed Balance Sheet	Condensed Balance Sheet December 31 2016 2015 (In thousands) Assets Cash in subsidiary bank $ 15,003 $ 19,874 Due from consolidated bank subsidiaries Money-market savings 1,767,184 865,274 Current income tax receivable 3,061 572 Other — 10 Total due from consolidated bank subsidiaries 1,770,245 865,856 Investments in consolidated subsidiaries Banks 15,003,964 15,581,931 Other 161,201 149,178 Investments in unconsolidated subsidiaries (note 19) 23,643 23,824 Investment in Bayview Lending Group LLC 11,908 30,264 Other assets 71,687 73,147 Total assets $ 17,057,651 $ 16,744,074 Liabilities Accrued expenses and other liabilities $ 54,487 $ 56,796 Long-term borrowings 516,542 513,989 Total liabilities 571,029 570,785 Shareholders’ equity 16,486,622 16,173,289 Total liabilities and shareholders’ equity $ 17,057,651 $ 16,744,074
Condensed Statement of Income	Condensed Statement of Income Year Ended December 31 2016 2015 2014 (In thousands, except per share) Income Dividends from consolidated bank subsidiaries $ 1,930,000 $ 480,000 $ 480,000 Equity in earnings of Bayview Lending Group LLC (10,752 ) (14,267 ) (16,672 ) Other income 5,530 2,364 7,755 Total income 1,924,778 468,097 471,083 Expense Interest on long-term borrowings 18,963 24,453 47,700 Other expense 21,361 16,793 15,107 Total expense 40,324 41,246 62,807 Income before income taxes and equity in undistributed income of subsidiaries 1,884,454 426,851 408,276 Income tax credits 17,247 19,965 27,284 Income before equity in undistributed income of subsidiaries 1,901,701 446,816 435,560 Equity in undistributed income of subsidiaries Net income of subsidiaries 1,343,413 1,112,851 1,110,686 Less: dividends received (1,930,000 ) (480,000 ) (480,000 ) Equity in undistributed income of subsidiaries (586,587 ) 632,851 630,686 Net income $ 1,315,114 $ 1,079,667 $ 1,066,246 Net income per common share Basic $ 7.80 $ 7.22 $ 7.47 Diluted 7.78 7.18 7.42
Condensed Statement of Cash Flow	Condensed Statement of Cash Flows Year Ended December 31 2016 2015 2014 (In thousands) Cash flows from operating activities Net income $ 1,315,114 $ 1,079,667 $ 1,066,246 Adjustments to reconcile net income to net cash provided by operating activities Equity in undistributed income of subsidiaries 586,587 (632,851 ) (630,686 ) Provision for deferred income taxes (3,157 ) (3,655 ) (6,522 ) Net change in accrued income and expense 12,898 21,780 23,419 Loss (gain) on sale of assets (2,342 ) 119 — Net cash provided by operating activities 1,909,100 465,060 452,457 Cash flows from investing activities Proceeds from sales or maturities of investment securities 51 755 — Other, net 13,619 14,038 10,721 Net cash provided by investing activities 13,670 14,793 10,721 Cash flows from financing activities Payments on long-term borrowings — (322,621 ) (350,010 ) Purchases of treasury stock (641,334 ) — — Dividends paid — common (441,891 ) (375,017 ) (371,199 ) Dividends paid — preferred (81,270 ) (81,270 ) (70,234 ) Redemption of Series D preferred stock (500,000 ) — — Proceeds from issuance of preferred stock 495,000 — 346,500 Other, net 143,764 76,364 110,601 Net cash used by financing activities (1,025,731 ) (702,544 ) (334,342 ) Net increase (decrease) in cash and cash equivalents 897,039 (222,691 ) 128,836 Cash and cash equivalents at beginning of year 885,148 1,107,839 979,003 Cash and cash equivalents at end of year $ 1,782,187 $ 885,148 $ 1,107,839 Supplemental disclosure of cash flow information Interest received during the year $ 1,931 $ 1,905 $ 2,094 Interest paid during the year 15,918 30,420 47,003 Income taxes received during the year 8,877 16,696 24,588

Significant Accounting Polici57

Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016
Significant Accounting Policies [Line Items]
Delinquent period of loans resulting in accrued interest being charged against income	90 days
Delinquent period of loans secured by real estate resulting in charge off	150 days
Maximum [Member]
Significant Accounting Policies [Line Items]
Loans secured by real estate delinquent period threshold for return to accrual status	90 days
Consumer loan delinquent period threshold for consideration for charge off	180 days
Estimated useful lives	10 years
Minimum [Member]
Significant Accounting Policies [Line Items]
Consumer loan delinquent period threshold for consideration for charge off	91 days
Estimated useful lives	5 years
Income tax benefit recognition criteria percentage threshold	50.00%

Acquisition and Divestiture - A

Acquisition and Divestiture - Additional Information (Detail)	Nov. 01, 2015USD ($)Officeshares	Nov. 30, 2015USD ($)	Apr. 30, 2015USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Business Acquisition [Line Items]
Proceeds from sales of investment securities				$ 63,513,000	$ 5,654,850,000	$ 16,000
Goodwill				4,593,112,000	4,593,112,000
Provision for credit losses				$ 190,000,000	170,000,000	124,000,000
Gain on sale of business net of tax			$ 23,000,000
Gain on sale of business before tax			45,000,000
Goodwill recorded			$ 11,000,000
Revenue on sale of business					9,000,000	34,000,000
Hudson City [Member]
Business Acquisition [Line Items]
Number of banking offices acquired in New Jersey, Connecticut and New York | Office	135
Gross amount of cash paid in the acquisition	$ 2,064,284,000
Business acquisition, purchase price	5,203,108,000
Proceeds from sales of investment securities		$ 5,800,000,000
Repayments of borrowings assumed in acquisition		$ 10,600,000,000
Goodwill	1,079,787,000
Core deposit intangible	$ 131,665,000
Amortization period of core deposit intangible				7 years
Loans acquired				$ 688,000,000
Discount recorded on purchased impaired loans				1,000,000,000
Estimated fair value of purchased impaired loans				18,300,000,000
Outstanding principal of purchased impaired loans				18,000,000,000
Other- than-temporary impairment					102,000,000	104,000,000
Merger-related expenses				$ 35,755,000	96,976,000	$ 0
Provision for credit losses					$ 21,000,000
Hudson City [Member] | Common Stock [Member]
Business Acquisition [Line Items]
Shares issued upon acquisition | shares	25,953,950

Acquisition and Divestiture - S

Acquisition and Divestiture - Schedule of Identifiable Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Nov. 01, 2015	Dec. 31, 2015	Dec. 31, 2016
Identifiable assets:
Goodwill		$ 4,593,112	$ 4,593,112
Liabilities:
Common stock awards converted		$ 28,243
Hudson City [Member]
Identifiable assets:
Cash and due from banks	$ 131,688
Interest-bearing deposits at banks	7,568,934
Investment securities	7,929,014
Loans	19,015,013
Goodwill	1,079,787
Core deposit intangible	131,665
Other assets	843,219
Total identifiable assets	36,699,320
Liabilities:
Deposits	17,879,589
Borrowings	13,211,598
Other liabilities	405,025
Total liabilities	31,496,212
Total consideration	5,203,108
Cash paid	2,064,284
Common stock awards converted	28,243
Total consideration	5,203,108
Hudson City [Member] | Common Stock [Member]
Liabilities:
Common stock issued (25,953,950 shares)	$ 3,110,581

Acquisition and Divestiture -60

Acquisition and Divestiture - Schedule of Identifiable Assets Acquired and Liabilities Assumed (Parenthetical) (Detail)	Nov. 01, 2015shares
Common Stock [Member] | Hudson City [Member]
Business Acquisition [Line Items]
Common stock issued	25,953,950

Acquisitions and Divestiture -

Acquisitions and Divestiture - Summary of Acquired Impaired Loans (Detail) - Hudson City [Member] $ in Thousands	Nov. 01, 2015USD ($)
Financing Receivable Impaired [Line Items]
Contractually required principal and interest at acquisition	$ 1,304,366
Contractual cash flows not expected to be collected	(498,919)
Expected cash flows at acquisition	805,447
Interest component of expected cash flows	(117,251)
Estimated fair value	$ 688,196

Acquisition and Divestiture - P

Acquisition and Divestiture - Pro Forma Information (Detail) - USD ($) $ in Thousands	2 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition Pro Forma Information [Abstract]
Total revenues actual since acquisition through	$ 111,168
Net income (loss) actual since acquisition through	$ (21,175)
Total revenues		$ 5,132,662	$ 5,406,291
Net income (loss)		$ 1,011,463	$ 1,445,779

Acquisition and Divestiture -63

Acquisition and Divestiture - Summary of Merger-Related Expenses (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary of merger-related expenses
Salaries and employee benefits	$ 1,623,600,000	$ 1,549,530,000	$ 1,404,950,000
Equipment and net occupancy	295,141,000	272,539,000	269,299,000
Outside data processing and software	172,389,000	164,133,000	151,568,000
Advertising and marketing	87,137,000	59,227,000	47,111,000
Printing, postage and supplies	39,546,000	38,491,000	38,201,000
Other costs of operations	682,014,000	660,475,000	688,990,000
Total other expense	3,047,485,000	2,822,932,000	2,689,474,000
Provision for credit losses	190,000,000	170,000,000	124,000,000
Hudson City [Member]
Summary of merger-related expenses
Salaries and employee benefits	5,334,000	51,287,000
Equipment and net occupancy	1,278,000	3,000
Outside data processing and software	1,067,000	785,000
Advertising and marketing	10,522,000	79,000
Printing, postage and supplies	1,482,000	504,000
Other costs of operations	16,072,000	23,318,000
Total other expense	35,755,000	75,976,000
Provision for credit losses		21,000,000
Total	$ 35,755,000	$ 96,976,000	$ 0

Investment Securities - Amortiz

Investment Securities - Amortized Cost and Estimated Fair Value of Investment Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	$ 13,338,301	$ 12,138,636
Investment securities available for sale, gross unrealized gains	135,286	174,699
Investment securities available for sale, gross unrealized losses	141,515	70,664
Investment securities available for sale, estimated fair value	13,332,072	12,242,671
Amortized cost for held to maturity	2,457,278	2,859,709
Gross unrealized gains for held to maturity	38,662	54,043
Gross unrealized losses for held to maturity	44,718	49,605
Estimated fair value for held to maturity	2,451,222	2,864,147
Other securities, Amortized cost	461,118	554,059
Other securities, Estimated fair value	461,118	554,059
Total Amortized cost	16,256,697	15,552,404
Total for Gross unrealized gains	173,948	228,742
Total for Gross unrealized losses	186,233	120,269
Total for Estimated fair value	16,244,412	15,660,877
U.S. Treasury and Federal Agencies [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	1,912,110	299,890
Investment securities available for sale, gross unrealized gains	386	294
Investment securities available for sale, gross unrealized losses	9,952	187
Investment securities available for sale, estimated fair value	1,902,544	299,997
Obligations of States and Political Subdivisions [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	3,570	5,924
Investment securities available for sale, gross unrealized gains	77	146
Investment securities available for sale, gross unrealized losses	6	42
Investment securities available for sale, estimated fair value	3,641	6,028
Amortized cost for held to maturity	60,858	118,431
Gross unrealized gains for held to maturity	267	1,003
Gross unrealized losses for held to maturity	224	421
Estimated fair value for held to maturity	60,901	119,013
Government Issued or Guaranteed [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	10,980,507	11,592,959
Investment securities available for sale, gross unrealized gains	88,343	142,370
Investment securities available for sale, gross unrealized losses	113,989	48,701
Investment securities available for sale, estimated fair value	10,954,861	11,686,628
Amortized cost for held to maturity	2,233,173	2,553,612
Gross unrealized gains for held to maturity	37,498	50,936
Gross unrealized losses for held to maturity	7,374	7,817
Estimated fair value for held to maturity	2,263,297	2,596,731
Privately Issued [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	45	74
Investment securities available for sale, gross unrealized gains		2
Investment securities available for sale, gross unrealized losses	1	2
Investment securities available for sale, estimated fair value	44	74
Amortized cost for held to maturity	157,704	181,091
Gross unrealized gains for held to maturity	897	2,104
Gross unrealized losses for held to maturity	37,120	41,367
Estimated fair value for held to maturity	121,481	141,828
Collateralized Debt Obligations [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost		28,438
Investment securities available for sale, gross unrealized gains		20,143
Investment securities available for sale, gross unrealized losses		1,188
Investment securities available for sale, estimated fair value		47,393
Other Debt Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	134,105	137,556
Investment securities available for sale, gross unrealized gains	1,407	1,514
Investment securities available for sale, gross unrealized losses	16,996	20,190
Investment securities available for sale, estimated fair value	118,516	118,880
Amortized cost for held to maturity	5,543	6,575
Estimated fair value for held to maturity	5,543	6,575
Equity Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	307,964	73,795
Investment securities available for sale, gross unrealized gains	45,073	10,230
Investment securities available for sale, gross unrealized losses	571	354
Investment securities available for sale, estimated fair value	$ 352,466	$ 83,671

Investment Securities - Additio

Investment Securities - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016USD ($)Investment	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Investment Holdings [Line Items]
Gross realized gains on sale of investment securities	$ 30,545,000	$ 0	$ 0
Number of investment securities with aggregate gross unrealized losses | Investment	1,083
Unrealized losses on individual investment securities	$ 186,233,000	120,269,000
Cost method investment securities	461,000,000
Investment securities pledged to secure debt carrying value	3,775,571,000
Pledged securities that can be sold or repledged	1,203,473,000	$ 2,136,712,000
Available-for-Sale Securities [Member]
Investment Holdings [Line Items]
Investment securities pledged to secure debt carrying value	3,240,079,000
Collateralized Debt Obligations [Member]
Investment Holdings [Line Items]
Net gain on securities sold	$ 30,000,000
Government Agency [Member]
Investment Holdings [Line Items]
Number of investment securities that exceeded ten percent of shareholders' equity | Investment	0
Non-U.S. Government [Member]
Investment Holdings [Line Items]
Number of investment securities that exceeded ten percent of shareholders' equity | Investment	0
Government Issued or Guaranteed [Member]
Investment Holdings [Line Items]
Number of investment securities that exceeded ten percent of shareholders' equity | Investment	0

Investment Securities - Investm

Investment Securities - Investment Ratings of All Privately Issued Mortgage-Backed Securities and Other Debt Securities (Detail) $ in Thousands	Dec. 31, 2016USD ($)
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Amortized Cost	$ 361,825
Total securities with disclosed rating, Estimated Fair Value	310,126
A or Better [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Estimated Fair Value	83,225
BBB [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Estimated Fair Value	63,369
BB [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Estimated Fair Value	30,373
B or Less [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Estimated Fair Value	90,730
Not Rated [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Estimated Fair Value	42,429
Obligations of States and Political Subdivisions [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Amortized Cost	64,428
Total securities with disclosed rating, Estimated Fair Value	64,542
Obligations of States and Political Subdivisions [Member] | A or Better [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Estimated Fair Value	47,023
Obligations of States and Political Subdivisions [Member] | Not Rated [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Estimated Fair Value	17,519
Privately Issued [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Amortized Cost	157,749
Total securities with disclosed rating, Estimated Fair Value	121,525
Privately Issued [Member] | A or Better [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Estimated Fair Value	30,760
Privately Issued [Member] | BBB [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Estimated Fair Value	16
Privately Issued [Member] | B or Less [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Estimated Fair Value	90,730
Privately Issued [Member] | Not Rated [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Estimated Fair Value	19
Other Debt Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Amortized Cost	139,648
Total securities with disclosed rating, Estimated Fair Value	124,059
Other Debt Securities [Member] | A or Better [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Estimated Fair Value	5,442
Other Debt Securities [Member] | BBB [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Estimated Fair Value	63,353
Other Debt Securities [Member] | BB [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Estimated Fair Value	30,373
Other Debt Securities [Member] | Not Rated [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total securities with disclosed rating, Estimated Fair Value	$ 24,891

Investment Securities - Amort67

Investment Securities - Amortized Cost and Estimated Fair Value of Collateralized Mortgage Obligations (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Amortized Cost And Fair Value Debt Securities [Abstract]
Collateralized mortgage obligations, Amortized cost	$ 162,027	$ 188,819
Collateralized mortgage obligations, Estimated fair value	$ 125,848	$ 149,632

Investment Securities - Amort68

Investment Securities - Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Debt securities available for sale:
Due in one year or less	$ 157,954
Due after one year through five years	1,760,301
Due after five years through ten years	2,689
Due after ten years	128,841
Total available for sale (amortized cost)	2,049,785
Mortgage-backed securities available for sale	10,980,552
Total	13,030,337
Debt securities held to maturity:
Due in one year or less	24,533
Due after one year through five years	34,073
Due after five years through ten years	2,252
Due after ten years	5,543
Total available for held to maturity (amortized cost)	66,401
Mortgage-backed securities held to maturity	2,390,877
Amortized cost for held to maturity	2,457,278	$ 2,859,709
Debt securities available for sale:
Due in one year or less	158,334
Due after one year through five years	1,750,542
Due after five years through ten years	3,132
Due after ten years	112,693
Total available for sale (fair value)	2,024,701
Mortgage-backed securities available for sale	10,954,905
Total	12,979,606
Debt securities held to maturity:
Due in one year or less	24,643
Due after one year through five years	33,963
Due after five years through ten years	2,295
Due after ten years	5,543
Total available for held to maturity (fair value)	66,444
Mortgage-backed securities held to maturity	2,384,778
Total	$ 2,451,222	$ 2,864,147

Investment Securities - Inves69

Investment Securities - Investment Securities in Continuous Unrealized Loss Position (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months	$ 8,458,946	$ 4,246,991
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses	(123,747)	(49,727)
Estimated fair value, 12 months or more	169,469	104,154
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(17,768)	(20,937)
Held to maturity, Estimated fair value, Less than 12 months	654,731	502,896
Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses	(8,190)	(2,136)
Held to maturity, Estimated fair value, 12 months or more	86,388	346,875
Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses	(36,528)	(47,469)
Total investment securities, fair value less than 12 months	9,113,677	4,749,887
Investment Securities Continuous Unrealized Loss Position Less Than Twelve Months Aggregate Losses	(131,937)	(51,863)
Total of investment securities, fair value, 12 Months or More	255,857	451,029
Investment Securities Continuous Unrealized Loss Position Twelve Months or Longer Aggregate Losses	(54,296)	(68,406)
U.S. Treasury and Federal Agencies [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months	1,710,241	147,508
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses	(9,950)	(187)
Estimated fair value, 12 months or more	2,295
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(2)
Obligations of States and Political Subdivisions [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months		865
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses		(2)
Estimated fair value, 12 months or more	593	1,335
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(6)	(40)
Held to maturity, Estimated fair value, Less than 12 months	17,988	42,913
Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses	(126)	(335)
Held to maturity, Estimated fair value, 12 months or more	11,891	5,853
Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses	(98)	(86)
Government Issued or Guaranteed [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months	6,730,829	4,061,899
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses	(113,374)	(48,534)
Estimated fair value, 12 months or more	81,003	7,216
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(615)	(167)
Held to maturity, Estimated fair value, Less than 12 months	618,832	459,983
Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses	(6,842)	(1,801)
Held to maturity, Estimated fair value, 12 months or more	17,481	228,867
Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses	(532)	(6,016)
Privately Issued Mortgage-Backed Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, 12 months or more	27	43
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(1)	(2)
Collateralized Debt Obligations [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months		5,711
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses		(335)
Estimated fair value, 12 months or more		2,063
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses		(853)
Other Debt Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months	100	12,935
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses	(1)	(462)
Estimated fair value, 12 months or more	85,400	93,344
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(16,995)	(19,728)
Equity Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months	17,776	18,073
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses	(422)	(207)
Estimated fair value, 12 months or more	151	153
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(149)	(147)
Privately Issued [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Held to maturity, Estimated fair value, Less than 12 months	17,911
Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses	(1,222)
Held to maturity, Estimated fair value, 12 months or more	57,016	112,155
Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses	$ (35,898)	$ (41,367)

Loans and Leases - Total Loans

Loans and Leases - Total Loans and Leases Outstanding (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Loans
Commercial, financial, etc.	$ 21,351,119	$ 19,223,419
Real estate:
Residential	22,584,141	26,249,059
Commercial	25,550,057	23,592,097
Construction	8,066,756	5,716,994
Consumer	12,130,094	11,584,347
Total loans	89,682,167	86,365,916
Leases
Commercial	1,419,510	1,353,318
Total loans and leases	91,101,677	87,719,234
Unearned discount	(248,261)	(229,735)
Loans and leases, net of unearned discount	$ 90,853,416	$ 87,489,499

Loans and Leases - Additional I

Loans and Leases - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loans And Leases Receivable [Line Items]
Commercial real estate loans held for sale	$ 643,000,000	$ 39,000,000
Charges incurred for reimbursement of loan	4,000,000	5,000,000	$ 4,000,000
Contractual principal and interest payments	578,000,000	768,000,000
Interest income that would have been recognized on nonaccrual and renegotiated loans if those loans were accruing interest at their originally contracted terms	68,371,000	56,784,000	58,314,000
Interest on nonaccrual and renegotiated loans included in interest income	33,941,000	30,735,000	$ 28,492,000
Guaranteed amount included in the estimated residual value of leased assets associated with direct financing leases	47,000,000	50,000,000
Amount of foreclosed residential real estate property held	129,000,000	172,000,000
Loans secured by residential real estate that were in the process of foreclosure	314,000,000	315,000,000
Loans secured by residential real estate that were in the process of foreclosure, serviced by other entities	$ 192,000,000
Percentage loans in the process of foreclosure, serviced by other entities, classified as purchased impaired	57.00%
Percentage loans in the process of foreclosure, serviced by other entities, classified as government guaranteed	20.00%
Director and Certain Officers [Member]
Loans And Leases Receivable [Line Items]
Exclusion limit of loans from related party disclosure	Less than $120,000
Borrowing by directors and certain officers of M&T and its banking subsidiaries and their associates	$ 63,543,000	$ 52,152,000
New borrowings by directors, certain officers and their associates	15,350,000
Repayments and other reductions of borrowings by directors, certain officers and their associates	$ 3,959,000
Maximum [Member]
Loans And Leases Receivable [Line Items]
Purchased impaired loans as a percentage of total assets	1.00%	1.00%
Commercial Real Estate [Member]
Loans And Leases Receivable [Line Items]
Loans serviced for others sold with credit recourse	$ 2,800,000,000
Loans pledged to secure outstanding borrowings from the FHLB of New York	12,500,000,000
Residential Mortgage Loans [Member]
Loans And Leases Receivable [Line Items]
Mortgage loans held for sale	414,000,000	$ 353,000,000
Loans pledged to secure outstanding borrowings from the FHLB of New York	17,800,000,000
Commercial Loans and Leases [Member]
Loans And Leases Receivable [Line Items]
Loans pledged to secure outstanding borrowings from the FHLB of New York	11,900,000,000
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	2,300,000,000
Other Consumer Loans [Member]
Loans And Leases Receivable [Line Items]
Loans pledged to secure outstanding borrowings from the FHLB of New York	$ 4,400,000,000

Loans and Leases - Outstanding

Loans and Leases - Outstanding Principal Balance and Carrying Amount of Loans and Included in Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Outstanding principal and carrying value of acquired loans recorded at fair value
Outstanding principal balance	$ 2,311,699	$ 3,122,935
Carrying amount	1,804,271	2,465,067
Commercial, Financial, Leasing, etc. [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	59,928	78,847
Commercial Real Estate [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	456,820	644,284
Residential Real Estate [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	799,802	1,016,129
Consumer [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	$ 487,721	$ 725,807

Loans and Leases - Summary of C

Loans and Leases - Summary of Changes in Accretable Yield for Acquired Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Purchased Impaired [Member]
Summary of changes in Accretable Yield for acquired loans
Balance at beginning of period	$ 184,618	$ 76,518	$ 37,230
Additions		117,251
Interest income	(52,769)	(28,551)	(21,263)
Reclassifications from nonaccretable balance	22,384	19,400	60,551
Balance at end of period	154,233	184,618	76,518
Other Acquired [Member]
Summary of changes in Accretable Yield for acquired loans
Balance at beginning of period	296,434	397,379	538,633
Interest income	(123,044)	(158,260)	(178,670)
Reclassifications from nonaccretable balance	22,677	49,930	24,907
Other	5,086	7,385	12,509
Balance at end of period	$ 201,153	$ 296,434	$ 397,379

Loans and Leases - Summary of74

Loans and Leases - Summary of Current, Past Due and Nonaccrual Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	$ 87,968,321	$ 84,400,551
30-89 Days Past Due	1,025,245	1,135,296
Accruing Loans Past Due 90 Days or More	300,659	317,441
Purchased Impaired	578,032	768,329
Nonaccrual	920,015	799,409
Loans and leases, net of unearned discount	90,853,416	87,489,499
Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing Loans Past Due 90 Days or More	61,144	68,473
Commercial, Financial, Leasing, etc. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	22,287,857	20,122,648
30-89 Days Past Due	53,503	52,868
Accruing Loans Past Due 90 Days or More	6,195	2,310
Purchased Impaired	641	1,902
Nonaccrual	261,434	241,917
Loans and leases, net of unearned discount	22,610,047	20,422,338
Commercial, Financial, Leasing, etc. [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing Loans Past Due 90 Days or More	417	693
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	25,076,684	23,111,673
30-89 Days Past Due	183,531	172,439
Accruing Loans Past Due 90 Days or More	7,054	12,963
Purchased Impaired	31,404	46,790
Nonaccrual	176,201	179,606
Loans and leases, net of unearned discount	25,487,744	23,532,261
Commercial [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing Loans Past Due 90 Days or More	12,870	8,790
Residential Builder and Developer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,884,989	1,507,856
30-89 Days Past Due	4,667	7,969
Accruing Loans Past Due 90 Days or More	5	5,760
Purchased Impaired	14,006	28,734
Nonaccrual	16,707	28,429
Loans and leases, net of unearned discount	1,922,326	1,585,673
Residential Builder and Developer [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing Loans Past Due 90 Days or More	1,952	6,925
Other Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	5,985,118	3,962,620
30-89 Days Past Due	77,701	65,932
Accruing Loans Past Due 90 Days or More	922	7,936
Purchased Impaired	14,274	24,525
Nonaccrual	18,111	16,363
Loans and leases, net of unearned discount	6,096,324	4,079,377
Other Commercial Construction [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing Loans Past Due 90 Days or More	198	2,001
Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	17,631,377	20,507,551
30-89 Days Past Due	485,468	560,312
Accruing Loans Past Due 90 Days or More	281,298	284,451
Purchased Impaired	378,549	488,599
Nonaccrual	229,242	153,281
Loans and leases, net of unearned discount	19,017,471	22,010,273
Residential [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing Loans Past Due 90 Days or More	11,537	16,079
Residential Limited Documentation [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	3,239,344	3,885,073
30-89 Days Past Due	88,366	137,289
Purchased Impaired	139,158	175,518
Nonaccrual	106,573	61,950
Loans and leases, net of unearned discount	3,573,441	4,259,830
Home Equity Lines and Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	5,502,091	5,805,222
30-89 Days Past Due	44,565	45,604
Purchased Impaired		2,261
Nonaccrual	81,815	84,467
Loans and leases, net of unearned discount	5,641,149	5,952,776
Home Equity Lines and Loans [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing Loans Past Due 90 Days or More	12,678	15,222
Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	2,869,232	2,446,473
30-89 Days Past Due	56,158	56,181
Nonaccrual	18,674	16,597
Loans and leases, net of unearned discount	2,944,065	2,519,257
Automobile [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing Loans Past Due 90 Days or More	1	6
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	3,491,629	3,051,435
30-89 Days Past Due	31,286	36,702
Accruing Loans Past Due 90 Days or More	5,185	4,021
Nonaccrual	11,258	16,799
Loans and leases, net of unearned discount	3,560,849	3,127,714
Other [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing Loans Past Due 90 Days or More	$ 21,491	$ 18,757

Loans and Leases - Loan Modific

Loans and Leases - Loan Modification Activities that were Considered Troubled Debt Restructurings (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)Modification	Dec. 31, 2015USD ($)Modification	Dec. 31, 2014USD ($)Modification
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	739	817	760
Pre-modification, Recorded Investment	$ 279,696	$ 204,800	$ 134,351
Post-modification, Recorded Investment	268,415	198,405	130,190
Financial Effects of Modification, Recorded Investment	(11,281)	(6,395)	(4,161)
Financial Effects of Modification, Interest	$ (2,482)	$ (1,851)	$ (2,969)
Principal Deferral [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	56	49	39
Pre-modification, Recorded Investment	$ 24,323	$ 49,486	$ 19,077
Post-modification, Recorded Investment	23,558	48,388	18,997
Financial Effects of Modification, Recorded Investment	$ (765)	$ (1,098)	$ (80)
Principal Deferral [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	127	114	95
Pre-modification, Recorded Investment	$ 102,872	$ 55,621	$ 29,035
Post-modification, Recorded Investment	102,446	50,807	23,628
Financial Effects of Modification, Recorded Investment	$ (426)	$ (4,814)	$ (5,407)
Principal Deferral [Member] | Residential Builder and Developer [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	3	2	2
Pre-modification, Recorded Investment	$ 23,905	$ 10,650	$ 1,639
Post-modification, Recorded Investment	22,958	10,598	$ 1,639
Financial Effects of Modification, Recorded Investment	$ (947)	$ (52)
Principal Deferral [Member] | Other Commercial Construction [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	1	4	4
Pre-modification, Recorded Investment	$ 250	$ 368	$ 6,703
Post-modification, Recorded Investment	$ 250	460	6,611
Financial Effects of Modification, Recorded Investment		$ 92	$ (92)
Principal Deferral [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	73	58	28
Pre-modification, Recorded Investment	$ 11,082	$ 6,194	$ 2,710
Post-modification, Recorded Investment	11,771	6,528	2,905
Financial Effects of Modification, Recorded Investment	$ 689	$ 334	$ 195
Principal Deferral [Member] | Residential Limited Documentation [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	8	2	6
Pre-modification, Recorded Investment	$ 902	$ 426	$ 880
Post-modification, Recorded Investment	1,047	437	963
Financial Effects of Modification, Recorded Investment	$ 145	$ 11	$ 83
Principal Deferral [Member] | Home Equity Lines and Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	10	8	3
Pre-modification, Recorded Investment	$ 760	$ 2,175	$ 280
Post-modification, Recorded Investment	761	$ 2,175	$ 280
Financial Effects of Modification, Recorded Investment	$ 1
Principal Deferral [Member] | Automobile [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	117	192	208
Pre-modification, Recorded Investment	$ 1,124	$ 1,818	$ 3,293
Post-modification, Recorded Investment	$ 1,124	$ 1,818	$ 3,293
Principal Deferral [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	57	102	33
Pre-modification, Recorded Investment	$ 968	$ 1,995	$ 245
Post-modification, Recorded Investment	$ 968	$ 1,995	$ 245
Combination of Concession Types [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	23	6	7
Pre-modification, Recorded Investment	$ 15,695	$ 3,238	$ 1,152
Post-modification, Recorded Investment	15,603	3,242	1,198
Financial Effects of Modification, Recorded Investment	(92)	4	46
Financial Effects of Modification, Interest	$ (585)	$ (159)	$ (264)
Combination of Concession Types [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	37	9	7
Pre-modification, Recorded Investment	$ 51,221	$ 32,444	$ 19,167
Post-modification, Recorded Investment	41,673	31,439	19,030
Financial Effects of Modification, Recorded Investment	(9,548)	(1,005)	(137)
Financial Effects of Modification, Interest	$ (95)	$ (245)	$ (20)
Combination of Concession Types [Member] | Residential Builder and Developer [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	3
Pre-modification, Recorded Investment	$ 15,755
Post-modification, Recorded Investment	15,123
Financial Effects of Modification, Recorded Investment	$ (632)
Combination of Concession Types [Member] | Other Commercial Construction [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	2	2
Pre-modification, Recorded Investment	$ 2,863	$ 10,375
Post-modification, Recorded Investment	2,782	10,375
Financial Effects of Modification, Recorded Investment	$ (81)
Financial Effects of Modification, Interest		$ (49)
Combination of Concession Types [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	46	26	30
Pre-modification, Recorded Investment	$ 8,975	$ 4,024	$ 4,211
Post-modification, Recorded Investment	9,367	4,277	4,287
Financial Effects of Modification, Recorded Investment	392	253	76
Financial Effects of Modification, Interest	$ (120)	$ (483)	$ (483)
Combination of Concession Types [Member] | Residential Limited Documentation [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	13	9	21
Pre-modification, Recorded Investment	$ 2,658	$ 1,536	$ 3,806
Post-modification, Recorded Investment	2,917	1,635	3,846
Financial Effects of Modification, Recorded Investment	259	99	40
Financial Effects of Modification, Interest	$ (706)	$ (121)	$ (386)
Combination of Concession Types [Member] | Home Equity Lines and Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	93	63	47
Pre-modification, Recorded Investment	$ 11,110	$ 5,203	$ 5,031
Post-modification, Recorded Investment	11,110	5,204	5,031
Financial Effects of Modification, Recorded Investment		1
Financial Effects of Modification, Interest	$ (916)	$ (677)	$ (560)
Combination of Concession Types [Member] | Automobile [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	8	57	81
Pre-modification, Recorded Investment	$ 85	$ 948	$ 1,189
Post-modification, Recorded Investment	85	948	1,189
Financial Effects of Modification, Interest	$ (3)	$ (43)	$ (100)
Combination of Concession Types [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	17	40	70
Pre-modification, Recorded Investment	$ 196	$ 396	$ 2,502
Post-modification, Recorded Investment	196	396	2,502
Financial Effects of Modification, Interest	$ (32)	$ (45)	$ (761)
Interest Rate Reduction [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	1		1
Pre-modification, Recorded Investment	$ 129		$ 255
Post-modification, Recorded Investment	129		252
Financial Effects of Modification, Recorded Investment			(3)
Financial Effects of Modification, Interest	$ (25)		$ (48)
Interest Rate Reduction [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification		1
Pre-modification, Recorded Investment		$ 99
Post-modification, Recorded Investment		99
Financial Effects of Modification, Interest		$ (19)
Interest Rate Reduction [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification			11
Pre-modification, Recorded Investment			$ 1,146
Post-modification, Recorded Investment			1,222
Financial Effects of Modification, Recorded Investment			76
Financial Effects of Modification, Interest			$ (152)
Interest Rate Reduction [Member] | Home Equity Lines and Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification			6
Pre-modification, Recorded Investment			$ 535
Post-modification, Recorded Investment			535
Financial Effects of Modification, Interest			$ (120)
Interest Rate Reduction [Member] | Automobile [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification		7	9
Pre-modification, Recorded Investment		$ 137	$ 152
Post-modification, Recorded Investment		137	152
Financial Effects of Modification, Interest		$ (10)	$ (12)
Interest Rate Reduction [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification			4
Pre-modification, Recorded Investment			$ 293
Post-modification, Recorded Investment			293
Financial Effects of Modification, Interest			$ (63)
Other [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	1	3	1
Pre-modification, Recorded Investment	$ 4,723	$ 4,169	$ 650
Post-modification, Recorded Investment	4,447	4,087
Financial Effects of Modification, Recorded Investment	$ (276)	$ (82)	$ (650)
Other [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification		3	3
Pre-modification, Recorded Investment		$ 12,965	$ 29,912
Post-modification, Recorded Investment		12,827	31,604
Financial Effects of Modification, Recorded Investment		$ (138)	$ 1,692
Other [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification		1	1
Pre-modification, Recorded Investment		$ 267	$ 188
Post-modification, Recorded Investment		$ 267	$ 188
Other [Member] | Automobile [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	38	46	42
Pre-modification, Recorded Investment	$ 55	$ 150	$ 255
Post-modification, Recorded Investment	$ 55	$ 150	$ 255
Other [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	5	13	1
Pre-modification, Recorded Investment	$ 45	$ 116	$ 45
Post-modification, Recorded Investment	$ 45	$ 116	$ 45

Loans and Leases - Summary of L

Loans and Leases - Summary of Lease Financing Receivables (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Direct financings:
Lease payments receivable	$ 1,136,815	$ 1,058,605
Estimated residual value of leased assets	79,449	81,269
Unearned income	(107,535)	(102,723)
Investment in direct financings	1,108,729	1,037,151
Leveraged leases:
Lease payments receivable	92,918	95,316
Estimated residual value of leased assets	110,328	118,128
Unearned income	(38,760)	(41,556)
Investment in leveraged leases	164,486	171,888
Total investment in leases	1,273,215	1,209,039
Deferred taxes payable arising from leveraged leases	$ 139,067	$ 160,603

Loans and Leases - Minimum Futu

Loans and Leases - Minimum Future Lease Payments to be Received from Lease Financings (Detail) $ in Thousands	Dec. 31, 2016USD ($)
Receivables [Abstract]
2,017	$ 301,611
2,018	276,524
2,019	209,835
2,020	150,631
2,021	101,403
Later years	189,729
Total	$ 1,229,733

Allowance for Credit Losses - C

Allowance for Credit Losses - Changes in Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$ 955,992	$ 919,562	$ 916,676
Provision for credit losses	190,000	170,000	124,000
Net charge-offs
Charge-offs	(231,255)	(198,373)	(178,742)
Recoveries	74,260	64,803	57,628
Net (charge-offs) recoveries	(156,995)	(133,570)	(121,114)
Ending balance	988,997	955,992	919,562
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	300,404	288,038	273,383
Provision for credit losses	59,506	43,065	51,410
Net charge-offs
Charge-offs	(59,244)	(60,983)	(58,943)
Recoveries	30,167	30,284	22,188
Net (charge-offs) recoveries	(29,077)	(30,699)	(36,755)
Ending balance	330,833	300,404	288,038
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	326,831	307,927	324,978
Provision for credit losses	33,627	25,768	(13,779)
Net charge-offs
Charge-offs	(4,805)	(16,487)	(14,058)
Recoveries	7,066	9,623	10,786
Net (charge-offs) recoveries	2,261	(6,864)	(3,272)
Ending balance	362,719	326,831	307,927
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	72,238	61,910	78,656
Provision for credit losses	6,902	19,133	(3,974)
Net charge-offs
Charge-offs	(26,133)	(13,116)	(21,351)
Recoveries	8,120	4,311	8,579
Net (charge-offs) recoveries	(18,013)	(8,805)	(12,772)
Ending balance	61,127	72,238	61,910
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	178,320	186,033	164,644
Provision for credit losses	90,134	79,489	89,704
Net charge-offs
Charge-offs	(141,073)	(107,787)	(84,390)
Recoveries	28,907	20,585	16,075
Net (charge-offs) recoveries	(112,166)	(87,202)	(68,315)
Ending balance	156,288	178,320	186,033
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	78,199	75,654	75,015
Provision for credit losses	(169)	2,545	639
Net charge-offs
Ending balance	$ 78,030	$ 78,199	$ 75,654

Allowance for Credit Losses - A

Allowance for Credit Losses - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan delinquent period	90 days
Minimum delinquency period for loan level collectability analysis consumer mortgage	150 days
Residential Mortgage Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value of loans for which partial charge-off has been recognized	$ 44	$ 55
Mortgage loans on real real estate not requiring charge off due to collateral carrying amount	16	20
Home Equity Loans and Lines of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value of loans for which partial charge-off has been recognized	32	21
Mortgage loans on real real estate not requiring charge off due to collateral carrying amount	$ 39	$ 28

Allowance for Credit Losses - I

Allowance for Credit Losses - Impaired Loans and Leases (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	$ 484,498	$ 507,154
Unpaid principal balance with related allowance	558,385	567,962
Related allowance	83,054	90,093
Recorded investment with no related allowance	276,634	273,437
Unpaid principal balance with no related allowance	351,788	367,741
Recorded investment	761,132	780,591
Unpaid principal balance	910,173	935,703
Commercial Real Estate [Member]
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	71,862	85,974
Unpaid principal balance with related allowance	86,666	95,855
Related allowance	11,620	18,764
Recorded investment with no related allowance	113,276	101,340
Unpaid principal balance with no related allowance	121,846	116,230
Recorded investment	185,138	187,314
Unpaid principal balance	208,512	212,085
Automobile [Member]
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	16,982	22,525
Unpaid principal balance with related allowance	18,272	22,525
Related allowance	3,740	4,709
Recorded investment	16,982	22,525
Unpaid principal balance	18,272	22,525
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	168,072	179,037
Unpaid principal balance with related allowance	184,432	195,821
Related allowance	48,480	44,752
Recorded investment with no related allowance	100,805	93,190
Unpaid principal balance with no related allowance	124,786	110,735
Recorded investment	268,877	272,227
Unpaid principal balance	309,218	306,556
Residential Builder and Developer [Member]
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	7,396	3,316
Unpaid principal balance with related allowance	8,361	5,101
Related allowance	506	196
Recorded investment with no related allowance	14,368	27,651
Unpaid principal balance with no related allowance	21,124	47,246
Recorded investment	21,764	30,967
Unpaid principal balance	29,485	52,347
Other Commercial Construction [Member]
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	2,475	3,548
Unpaid principal balance with related allowance	2,731	3,843
Related allowance	448	348
Recorded investment with no related allowance	15,933	13,221
Unpaid principal balance with no related allowance	35,281	31,477
Recorded investment	18,408	16,769
Unpaid principal balance	38,012	35,320
Residential [Member]
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	86,680	79,558
Unpaid principal balance with related allowance	105,944	96,751
Related allowance	3,457	4,727
Recorded investment with no related allowance	16,823	19,621
Unpaid principal balance with no related allowance	24,161	30,940
Recorded investment	103,503	99,179
Unpaid principal balance	130,105	127,691
Residential Limited Documentation [Member]
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	82,547	90,356
Unpaid principal balance with related allowance	97,718	104,251
Related allowance	6,000	8,000
Recorded investment with no related allowance	15,429	18,414
Unpaid principal balance with no related allowance	24,590	31,113
Recorded investment	97,976	108,770
Unpaid principal balance	122,308	135,364
Home Equity Lines and Loans [Member]
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	44,693	25,220
Unpaid principal balance with related allowance	48,965	26,195
Related allowance	8,027	3,777
Recorded investment	44,693	25,220
Unpaid principal balance	48,965	26,195
Other [Member]
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	3,791	17,620
Unpaid principal balance with related allowance	5,296	17,620
Related allowance	776	4,820
Recorded investment	3,791	17,620
Unpaid principal balance	$ 5,296	$ 17,620

Allowance for Credit Losses -81

Allowance for Credit Losses - Interest Income Recognized on Impaired Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	$ 769,259	$ 768,501	$ 852,027
Interest income recognized, Total	31,397	27,643	27,799
Interest income recognized, Cash basis	21,885	19,046	18,573
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	175,877	166,628	184,773
Interest income recognized, Total	4,878	6,243	4,029
Interest income recognized, Cash basis	4,878	6,243	4,029
Commercial, Financial, Leasing, etc. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	277,647	236,201	181,932
Interest income recognized, Total	8,342	2,933	2,251
Interest income recognized, Cash basis	8,342	2,933	2,251
Residential Builder and Developer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	29,237	59,457	91,149
Interest income recognized, Total	2,300	335	142
Interest income recognized, Cash basis	2,300	335	142
Other Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	19,697	20,276	62,734
Interest income recognized, Total	644	2,311	1,893
Interest income recognized, Cash basis	644	2,311	1,893
Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	98,394	101,483	126,005
Interest income recognized, Total	6,227	6,188	9,180
Interest income recognized, Cash basis	3,154	4,037	6,978
Residential Limited Documentation [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	103,060	118,449	133,800
Interest income recognized, Total	5,999	6,380	6,613
Interest income recognized, Cash basis	1,975	2,638	2,546
Home Equity Lines and Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	36,493	21,523	18,083
Interest income recognized, Total	1,325	905	750
Interest income recognized, Cash basis	410	261	248
Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	19,636	25,675	35,173
Interest income recognized, Total	1,242	1,619	2,251
Interest income recognized, Cash basis	99	175	295
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	9,218	18,809	18,378
Interest income recognized, Total	440	729	690
Interest income recognized, Cash basis	$ 83	$ 113	$ 191

Allowance for Credit Losses - S

Allowance for Credit Losses - Summary of Loan Grades (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	$ 90,853,416	$ 87,489,499
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	22,610,047	20,422,338
Commercial, Financial, Leasing, etc. [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	21,398,581	19,442,183
Commercial, Financial, Leasing, etc. [Member] | Criticized Accrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	950,032	738,238
Commercial, Financial, Leasing, etc. [Member] | Criticized Nonaccrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	261,434	241,917
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	25,487,744	23,532,261
Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	24,570,269	22,697,398
Commercial [Member] | Criticized Accrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	741,274	655,257
Commercial [Member] | Criticized Nonaccrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	176,201	179,606
Residential Builder and Developer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	1,922,326	1,585,673
Residential Builder and Developer [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	1,789,071	1,497,465
Residential Builder and Developer [Member] | Criticized Accrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	116,548	59,779
Residential Builder and Developer [Member] | Criticized Nonaccrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	16,707	28,429
Other Commercial Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	6,096,324	4,079,377
Other Commercial Construction [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	5,912,351	3,834,137
Other Commercial Construction [Member] | Criticized Accrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	165,862	228,877
Other Commercial Construction [Member] | Criticized Nonaccrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	$ 18,111	$ 16,363

Allowance for Credit Losses -83

Allowance for Credit Losses - Allocation of Allowance for Credit Losses on Basis of Company's Impairment Methodology (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	$ 82,980	$ 89,960
Allowance for credit losses	822,392	783,750
Allowance for credit losses	988,997	955,992	$ 919,562	$ 916,676
Purchased Impaired [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	5,595	4,083
Allocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	910,967	877,793
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	78,030	78,199	$ 75,654	$ 75,015
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	48,480	44,752
Allowance for credit losses	282,353	255,615
Commercial, Financial, Leasing, etc. [Member] | Purchased Impaired [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses		37
Commercial, Financial, Leasing, etc. [Member] | Allocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	330,833	300,404
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	12,500	19,175
Allowance for credit losses	348,301	307,000
Commercial Real Estate [Member] | Purchased Impaired [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	1,918	656
Commercial Real Estate [Member] | Allocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	362,719	326,831
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	9,457	12,727
Allowance for credit losses	47,993	57,624
Residential Real Estate [Member] | Purchased Impaired [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	3,677	1,887
Residential Real Estate [Member] | Allocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	61,127	72,238
Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	12,543	13,306
Allowance for credit losses	143,745	163,511
Consumer Loans [Member] | Purchased Impaired [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses		1,503
Consumer Loans [Member] | Allocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	$ 156,288	$ 178,320

Allowance for Credit Losses - R

Allowance for Credit Losses - Recorded Investment in Loans and Leases on Basis of Company's Impairment Methodology (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	$ 90,853,416	$ 87,489,499
Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	760,452	779,673
Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	89,514,932	85,941,497
Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	578,032	768,329
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	22,610,047	20,422,338
Commercial, Financial, Leasing, etc. [Member] | Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	268,877	272,227
Commercial, Financial, Leasing, etc. [Member] | Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	22,340,529	20,148,209
Commercial, Financial, Leasing, etc. [Member] | Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	641	1,902
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	33,506,394	29,197,311
Commercial Real Estate [Member] | Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	224,630	234,132
Commercial Real Estate [Member] | Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	33,222,080	28,863,130
Commercial Real Estate [Member] | Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	59,684	100,049
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	22,590,912	26,270,103
Residential Real Estate [Member] | Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	201,479	207,949
Residential Real Estate [Member] | Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	21,871,726	25,398,037
Residential Real Estate [Member] | Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	517,707	664,117
Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	12,146,063	11,599,747
Consumer Loans [Member] | Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	65,466	65,365
Consumer Loans [Member] | Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	$ 12,080,597	11,532,121
Consumer Loans [Member] | Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount		$ 2,261

Premises and Equipment - Summar

Premises and Equipment - Summary of Premises and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Land	$ 104,671	$ 105,435
Leasehold improvements	232,936	229,919
Premises and equipment, gross	1,437,117	1,406,579
Less: accumulated depreciation and amortization	761,854	739,897
Premises and equipment, net	675,263	666,682
Owned Assets [Member]
Property, Plant and Equipment [Line Items]
Buildings	448,442	443,507
Furniture and equipment	636,219	614,591
Less: accumulated depreciation and amortization	756,245	732,315
Capital Leases [Member]
Property, Plant and Equipment [Line Items]
Buildings		1,108
Furniture and equipment	14,849	12,019
Less: accumulated depreciation and amortization	$ 5,609	$ 7,582

Premises and Equipment - Additi

Premises and Equipment - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property Plant And Equipment Capitalized Interest Costs [Abstract]
Net lease expense for all operating leases	$ 113,663,000	$ 102,356,000	$ 104,297,000

Capitalized Servicing Assets -

Capitalized Servicing Assets - Changes in Capitalized Servicing Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Servicing Asset at Amortized Cost [Line Items]
Amortized value, Beginning balance	$ 202,724	$ 186,917	$ 210,101
Originations	68,735	65,470	44,207
Purchases	638	243	1,019
Amortization	(50,982)	(49,906)	(68,410)
Amortized value, ending balance	221,115	202,724	186,917
Ending balance, net	221,115	202,724	186,917
Residential Mortgage Loans [Member]
Servicing Asset at Amortized Cost [Line Items]
Amortized value, Beginning balance	118,303	109,871	126,377
Originations	28,618	35,556	28,285
Purchases	638	243	289
Amortization	(30,208)	(27,367)	(45,080)
Amortized value, ending balance	117,351	118,303	109,871
Ending balance, net	117,351	118,303	109,871
Commercial Mortgage Loans [Member]
Servicing Asset at Amortized Cost [Line Items]
Amortized value, Beginning balance	83,692	72,939	72,499
Originations	40,117	29,914	15,922
Purchases			730
Amortization	(20,045)	(19,161)	(16,212)
Amortized value, ending balance	103,764	83,692	72,939
Ending balance, net	103,764	83,692	72,939
Other [Member]
Servicing Asset at Amortized Cost [Line Items]
Amortized value, Beginning balance	729	4,107	11,225
Amortization	$ (729)	(3,378)	(7,118)
Amortized value, ending balance		729	4,107
Ending balance, net		$ 729	$ 4,107

Capitalized Servicing Assets 88

Capitalized Servicing Assets - Additional Information (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Residential Mortgage Loans [Member]
Servicing Assets at Fair Value [Line Items]
Mortgage loans serviced for others	$ 53,200	$ 61,700	$ 53,200	$ 61,700	$ 67,200
Estimated fair value of capitalized mortgage loan servicing assets	$ 235	$ 249	$ 235	$ 249
Weighted average discount rates used to estimate fair value of capitalized mortgaged loan servicing assets	12.20%	12.40%
Residential Mortgage Loans [Member] | LIBOR [Member]
Servicing Assets at Fair Value [Line Items]
Discounted rate represented weighted-average option-adjusted basis spread point percentage			10.95%	11.19%
Residential Mortgage Sub Servicing Loan [Member]
Servicing Assets at Fair Value [Line Items]
Mortgage loans serviced for others	$ 30,400	$ 37,800	$ 30,400	$ 37,800	42,100
Commercial Mortgage Loans [Member]
Servicing Assets at Fair Value [Line Items]
Mortgage loans serviced for others	11,800	11,000	11,800	11,000	$ 11,300
Estimated fair value of capitalized mortgage loan servicing assets	$ 119	$ 99	$ 119	$ 99
Weighted average discount rates used to estimate fair value of capitalized mortgaged loan servicing assets	18.00%	18.00%	18.00%

Capitalized Servicing Assets 89

Capitalized Servicing Assets - Economic Assumptions Used to Determine Fair Value of Capitalized Servicing Rights and Sensitivity of Value to Changes in Assumptions (Detail) - USD ($)	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016
Residential Mortgage Loans [Member]
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]
Weighted-average prepayment speeds			11.30%
Impact on fair value of 10% adverse change	$ (8,525,000)		$ (8,525,000)
Impact on fair value of 20% adverse change	$ (16,390,000)		$ (16,390,000)
Weighted-average OAS	10.95%		10.95%
Impact on fair value of 10% adverse change	$ (7,106,000)		$ (7,106,000)
Impact on fair value of 20% adverse change	$ (13,779,000)		$ (13,779,000)
Weighted-average discount rate	12.20%	12.40%
Commercial Mortgage Loans [Member]
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]
Weighted-average discount rate	18.00%	18.00%	18.00%
Impact on fair value of 10% adverse change	$ (5,285,000)		$ (5,285,000)
Impact on fair value of 20% adverse change	$ (10,186,000)		$ (10,186,000)

Goodwill and Other Intangible90

Goodwill and Other Intangible Assets - Total Amortizing Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,064,727	$ 1,064,727
Accumulated Amortization	967,072	924,459
Net Carrying Amount	97,655	140,268
Core Deposit [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	887,459	887,459
Accumulated Amortization	789,988	750,624
Net Carrying Amount	97,471	136,835
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	177,268	177,268
Accumulated Amortization	177,084	173,835
Net Carrying Amount	$ 184	$ 3,433

Goodwill and Other Intangible91

Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill And Other Intangible Assets [Line Items]
Amortization of core deposit and other intangible assets	$ 42,613,000	$ 26,424,000	$ 33,824,000
Core Deposit and Other Intangible Assets [Member]
Goodwill And Other Intangible Assets [Line Items]
Estimated useful lives	8 years
Remaining weighted-average amortization period	6 years
Amortization of core deposit and other intangible assets	$ 42,613,000	$ 26,424,000	$ 33,824,000
Minimum [Member]
Goodwill And Other Intangible Assets [Line Items]
Estimated useful lives	5 years
Minimum [Member] | Core Deposit and Other Intangible Assets [Member]
Goodwill And Other Intangible Assets [Line Items]
Estimated useful lives	5 years
Maximum [Member]
Goodwill And Other Intangible Assets [Line Items]
Estimated useful lives	10 years
Maximum [Member] | Core Deposit and Other Intangible Assets [Member]
Goodwill And Other Intangible Assets [Line Items]
Estimated useful lives	10 years

Goodwill and Other Intangible92

Goodwill and Other Intangible Assets - Estimated Amortization Expense in Future Years (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
2,017	$ 30,305
2,018	23,462
2,019	18,026
2,020	13,323
2,021	8,621
Later years	3,918
Future Amortization Expense, Total	$ 97,655	$ 140,268

Goodwill and Other Intangible93

Goodwill and Other Intangible Assets - Summary of Goodwill Assigned to Reportable Segments for Purposes of Testing for Impairment (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Line Items]
Goodwill	$ 4,593,112	$ 4,593,112
Business Banking [Member]
Goodwill [Line Items]
Goodwill	864,366	864,366
Commercial Banking [Member]
Goodwill [Line Items]
Goodwill	1,401,873	1,401,873
Commercial Real Estate [Member]
Goodwill [Line Items]
Goodwill	654,389	654,389
Retail Banking [Member]
Goodwill [Line Items]
Goodwill	1,309,191	1,309,191
All Other [Member]
Goodwill [Line Items]
Goodwill	$ 363,293	$ 363,293

Borrowings - Amounts and Intere

Borrowings - Amounts and Interest Rates of Short-term Borrowings (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Borrowings [Line Items]
Weighted-average interest rate	0.32%	0.40%	0.07%
Daily-average amount outstanding	$ 893,822,000	$ 548,005,000	$ 214,736,000
Weighted-average interest rate	0.41%	0.31%	0.05%
Federal Funds Purchased and Repurchase Agreements	$ 163,442,000	$ 150,546,000
Other Short-term Borrowings		1,981,636,000
Federal funds purchased and short term borrowings	$ 163,442,000	$ 2,132,182,000	$ 192,676,000
Federal Funds Purchased and Repurchase Agreements [Member]
Schedule Of Borrowings [Line Items]
Weighted-average interest rate	0.32%	0.06%	0.07%
Highest amount at a month-end	$ 225,940,000	$ 202,951,000	$ 280,350,000
Daily-average amount outstanding	$ 203,853,000	$ 187,167,000	$ 214,736,000
Weighted-average interest rate	0.28%	0.08%	0.05%
Federal Funds Purchased and Repurchase Agreements	$ 163,442,000	$ 150,546,000	$ 192,676,000
Other Short-term Borrowings [Member]
Schedule Of Borrowings [Line Items]
Weighted-average interest rate		0.43%
Highest amount at a month-end	1,974,013,000	$ 1,989,257,000
Daily-average amount outstanding	$ 689,969,000	$ 360,838,000
Weighted-average interest rate	0.44%	0.43%
Other Short-term Borrowings		$ 1,981,636,000

Borrowings - Lines of Credit Un

Borrowings - Lines of Credit Under Formal Agreements (Detail) - M&T Bank [Member] $ in Thousands	Dec. 31, 2016USD ($)
Schedule Of Borrowings [Line Items]
Outstanding borrowings	$ 1,154,828
Unused	$ 32,573,956

Borrowings - Additional Informa

Borrowings - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Schedule Of Borrowings [Line Items]
Minimum contractual interest rates of long-term agreements to repurchase securities	3.65%	3.61%
Maximum contractual interest rates of long-term agreements to repurchase securities	4.58%	4.58%
Weighted-average contractual interest rates of long term agreements to repurchase securities	4.05%	4.00%
Repurchase dates of the long-term agreements outstanding	2,020
Collateral posted	$ 1,100,000,000	$ 2,000,000,000
Trust preferred capital securities	0.00%	25.00%
Debt Maturity, Start Year	Jan. 1, 2027
Debt Maturity, End Year	Dec. 31, 2033
Minimum [Member]
Schedule Of Borrowings [Line Items]
Variable interest rate of Senior Notes /Junior Subordinated Debentures	1.74%	1.18%
Maximum [Member]
Schedule Of Borrowings [Line Items]
Variable interest rate of Senior Notes /Junior Subordinated Debentures	4.23%	3.67%
FHLBs Facility [Member]
Schedule Of Borrowings [Line Items]
Borrowing facilities available with FHLB's amount	$ 22,500,000,000
Federal Reserve Bank of New York [Member]
Schedule Of Borrowings [Line Items]
Line of credit facility	$ 11,200,000,000
Variable Rate Senior Notes [Member]
Schedule Of Borrowings [Line Items]
Weighted-average variable rates payable	1.22%	0.69%
Variable Rate Senior Notes [Member] | Minimum [Member]
Schedule Of Borrowings [Line Items]
Variable interest rate of Senior Notes /Junior Subordinated Debentures	1.18%	0.62%
Variable Rate Senior Notes [Member] | Maximum [Member]
Schedule Of Borrowings [Line Items]
Variable interest rate of Senior Notes /Junior Subordinated Debentures	1.26%	0.75%
Long-term Fixed Rate Advances From FHLB [Member]
Schedule Of Borrowings [Line Items]
Advances from the FHLB maturity date	2,035
Long-term Fixed Rate Advances From FHLB [Member] | Minimum [Member]
Schedule Of Borrowings [Line Items]
Variable contractual interest rate of long-term debt	1.17%
Long-term Fixed Rate Advances From FHLB [Member] | Maximum [Member]
Schedule Of Borrowings [Line Items]
Variable contractual interest rate of long-term debt	7.32%
Long-term Fixed Rate Advances From FHLB [Member] | Weighted Average [Member]
Schedule Of Borrowings [Line Items]
Variable contractual interest rate of long-term debt	1.65%	1.66%
Subordinated Capital Notes [Member]
Schedule Of Borrowings [Line Items]
Interest rate of debt instrument	1.97%	1.64%
Subordinated Variable Rate Notes Due 2021 [Member]
Schedule Of Borrowings [Line Items]
Interest rate of debt instrument	1.57%
Junior Subordinated Debt [Member]
Schedule Of Borrowings [Line Items]
Weighted-average variable rates payable	2.33%	1.78%

Borrowings - Long-term Borrowin

Borrowings - Long-term Borrowings (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Schedule Of Borrowings [Line Items]
Fixed rates	$ 1,154,737	$ 1,158,216
Agreements to repurchase securities	1,084,694	1,899,281
Other	12,010	20,902
Long-term borrowings	9,493,835	10,653,858
Variable Rate Notes Due 2016 [Member]
Schedule Of Borrowings [Line Items]
Variable rates		300,000
Variable Rate Term Loans Due 2017 [Member]
Schedule Of Borrowings [Line Items]
Variable rates	550,000	550,000
1.25% Due 2017 [Member]
Schedule Of Borrowings [Line Items]
Variable rates	499,999	499,984
1.40% Due 2017 [Member]
Schedule Of Borrowings [Line Items]
Variable rates	749,946	749,851
1.45% Due 2018 [Member]
Schedule Of Borrowings [Line Items]
Variable rates	501,829	503,527
2.25% Due 2019 [Member]
Schedule Of Borrowings [Line Items]
Variable rates	649,012	648,628
2.30% Due 2019 [Member]
Schedule Of Borrowings [Line Items]
Variable rates	749,473	749,219
2.10% Due 2020 [Member]
Schedule Of Borrowings [Line Items]
Variable rates	749,735	749,650
2.90% Due 2025 [Member]
Schedule Of Borrowings [Line Items]
Variable rates	749,320	749,236
8.5% due 2018 [Member]
Schedule Of Borrowings [Line Items]
Subordinated notes	207,651	213,417
6.625% due 2017 [Member]
Schedule Of Borrowings [Line Items]
Subordinated notes	409,526	419,800
5.585% due 2020, Variable Rate Commenced 2015 [Member]
Schedule Of Borrowings [Line Items]
Subordinated notes	409,361	409,361
5.629% due 2021, Variable Rate Commenced 2016 [Member]
Schedule Of Borrowings [Line Items]
Subordinated notes	500,000	518,797
BSB Capital Trust I - 8.125%, due 2028 [Member]
Schedule Of Borrowings [Line Items]
Junior subordinated debentures associated with preferred capital securities	15,659	15,635
Provident Trust I - 8.29%, due 2028 [Member]
Schedule Of Borrowings [Line Items]
Junior subordinated debentures associated with preferred capital securities	26,293	25,817
Southern Financial Statutory Trust I - 10.60%, due 2030 [Member]
Schedule Of Borrowings [Line Items]
Junior subordinated debentures associated with preferred capital securities	6,620	6,583
First Maryland Capital I - due 2027 [Member]
Schedule Of Borrowings [Line Items]
Junior subordinated debentures associated with preferred capital securities	146,256	145,717
First Maryland Capital II - due 2027 [Member]
Schedule Of Borrowings [Line Items]
Junior subordinated debentures associated with preferred capital securities	147,954	147,291
Allfirst Asset Trust - due 2029 [Member]
Schedule Of Borrowings [Line Items]
Junior subordinated debentures associated with preferred capital securities	96,494	96,349
BSB Capital Trust III - due 2033 [Member]
Schedule Of Borrowings [Line Items]
Junior subordinated debentures associated with preferred capital securities	15,464	15,464
Provident Statutory Trust III - Due 2033 [Member]
Schedule Of Borrowings [Line Items]
Junior subordinated debentures associated with preferred capital securities	53,834	53,244
Southern Financial Capital Trust III - due 2033 [Member]
Schedule Of Borrowings [Line Items]
Junior subordinated debentures associated with preferred capital securities	$ 7,968	$ 7,889

Borrowings - Long-term Borrow98

Borrowings - Long-term Borrowings (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Schedule Of Borrowings [Line Items]
Debt Maturity, Start Date	Jan. 1, 2027
Debt Maturity, End Date	Dec. 31, 2033
Variable Rate Due 2016 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,016	2,016
Senior Notes Due 2017 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,017	2,017
1.25% Due 2017 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,017	2,017
Interest rate of debt instrument	1.25%	1.25%
1.40% Due 2017 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,017	2,017
Interest rate of debt instrument	1.40%	1.40%
1.45% Due 2018 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,018	2,018
Interest rate of debt instrument	1.45%	1.45%
2.25% Due 2019 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,019	2,019
Interest rate of debt instrument	2.25%	2.25%
2.30% Due 2019 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,019	2,019
Interest rate of debt instrument	2.30%	2.30%
2.10% Due 2020 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,020	2,020
Interest rate of debt instrument	2.10%	2.10%
2.90% Due 2025 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,025	2,025
Interest rate of debt instrument	2.90%	2.90%
8.5% due 2018 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,018	2,018
Interest rate of debt instrument	8.50%	8.50%
6.625% due 2017 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,017	2,017
Interest rate of debt instrument	6.625%	6.625%
5.585% due 2020, Variable Rate Commenced 2015 [Member]
Schedule Of Borrowings [Line Items]
Interest rate of debt instrument	5.585%	5.585%
Debt Maturity, Start Date	Jan. 1, 2015	Jan. 1, 2015
Debt Maturity, End Date	Dec. 31, 2020	Dec. 31, 2020
5.629% due 2021, Variable Rate Commenced 2016 [Member]
Schedule Of Borrowings [Line Items]
Interest rate of debt instrument	5.629%	5.629%
Debt Maturity, Start Date	Jan. 1, 2016	Jan. 1, 2016
Debt Maturity, End Date	Dec. 31, 2021	Dec. 31, 2021
BSB Capital Trust I - 8.125%, due 2028 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,028	2,028
Interest rate of debt instrument	8.125%	8.125%
Provident Trust I - 8.29%, due 2028 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,028	2,028
Interest rate of debt instrument	8.29%	8.29%
Southern Financial Statutory Trust I - 10.60%, due 2030 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,030	2,030
Interest rate of debt instrument	10.60%	10.60%
First Maryland Capital I - due 2027 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,027	2,027
First Maryland Capital II - due 2027 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,027	2,027
Allfirst Asset Trust - due 2029 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,029	2,029
BSB Capital Trust III - due 2033 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,033	2,033
Provident Statutory Trust III - Due 2033 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,033	2,033
Southern Financial Capital Trust III - due 2033 [Member]
Schedule Of Borrowings [Line Items]
Debt maturity date	2,033	2,033

Borrowings - Maturity of Long-t

Borrowings - Maturity of Long-term Borrowings (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Debt Disclosure [Abstract]
2,017	$ 3,442,484
2,018	714,358
2,019	2,299,502
2,020	1,269,939
2,021	500,144
Later years	1,267,408
Long-term borrowings	$ 9,493,835	$ 10,653,858

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, par value	$ 1	$ 1
Warrant [Member] | Assumed In Acquisition [Member]
Class of Stock [Line Items]
Exercise price of each class of warrants or rights outstanding	$ 518.96	$ 518.96
Warrant to purchase common stock	95,383	95,383

Shareholders' Equity - Issued a

Shareholders' Equity - Issued and Outstanding Preferred Stock (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Carrying value	$ 1,231,500	$ 1,231,500
Series A Fixed Rate Cumulative Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, Shares Issued	230,000	230,000
Preferred stock, Shares Outstanding	230,000	230,000
Carrying value	$ 230,000	$ 230,000
Series C Fixed Rate Cumulative Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, Shares Issued	151,500	151,500
Preferred stock, Shares Outstanding	151,500	151,500
Carrying value	$ 151,500	$ 151,500
Series D Fixed Rate Non-cumulative Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, Shares Issued		50,000
Preferred stock, Shares Outstanding		50,000
Carrying value		$ 500,000
Series E Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, Shares Issued	350,000	350,000
Preferred stock, Shares Outstanding	350,000	350,000
Carrying value	$ 350,000	$ 350,000
Series F Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, Shares Issued	50,000
Preferred stock, Shares Outstanding	50,000
Carrying value	$ 500,000

Shareholders' Equity - Issue102

Shareholders' Equity - Issued and Outstanding Preferred Stock (Parenthetical) (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Series A Fixed Rate Cumulative Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, liquidation preference per share	$ 1,000	$ 1,000
Preferred stock dividend rate	6.375%	6.375%
Exercise price of each class of warrants or rights outstanding	$ 73.86	$ 73.86
Warrants and rights outstanding	631,794	719,175
Warrants, year of expiration	2,018	2,018
Series C Fixed Rate Cumulative Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, liquidation preference per share	$ 1,000	$ 1,000
Preferred stock dividend rate	6.375%	6.375%
Series D Fixed Rate Non-cumulative Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, liquidation preference per share	$ 10,000	$ 10,000
Series E Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, liquidation preference per share	$ 1,000	$ 1,000
Preferred stock dividend rate	6.45%	6.45%
Date of change in the dividend rate	Feb. 14, 2024	Feb. 14, 2024
London Interbank offered rate plus basis points	361.00%	361.00%
Preferred shares redemption date	Feb. 15, 2024	Feb. 15, 2024
Preferred Stock, Redemption Feature, Redemption Term	90 days	90 days
Series F Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, liquidation preference per share	$ 10,000
Preferred stock dividend rate	5.125%
Date of change in the dividend rate	Oct. 31, 2026
London Interbank offered rate plus basis points	352.00%
Preferred shares redemption date	Nov. 1, 2026
Preferred Stock, Redemption Feature, Redemption Term	90 days

Stock-Based Compensation Pla103

Stock-Based Compensation Plans - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 65,000,000	$ 67,000,000	$ 65,000,000
Recognized income tax benefits related to stock-based compensation	$ 31,000,000	$ 29,000,000	$ 31,000,000
Shares under equity incentive compensation plan for future grant	3,667,800	3,954,712
Directors Stock Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issuable under deferred compensation plans	9,215	10,279
Shares issued in connection with deferred compensation plans	243,652
Deferred Bonus Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issuable under deferred compensation plans	23,188	26,365
Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issued	97,880	89,384	85,761
Common stock authorized for issuance	2,500,000
Cash received from exercise of stock options	$ 9,528,000	$ 9,296,000	$ 8,607,000
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	3 years	3 years	3 years	4 years
Unrecognized compensation cost expected to be recognized over a weighted-average period (in years)	1 year	1 year
Unrecognized compensation cost related to non-vested awards	$ 12,000,000
Shares issued	218,341	218,183	221,822
Restricted Stock Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average grant date fair value	$ 24,085,000	$ 24,726,000	$ 24,765,000
Restricted Stock Units (RSUs) [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost related to non-vested awards	$ 5,000,000
Shares issued	348,297	324,772	299,525
Weighted-average grant date fair value	$ 38,795,000	$ 37,070,000	$ 33,406,000
Stock Option Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	4 years
Stock options exercisable period, maximum	10 years 1 day
Cash realized from exercise of stock options	$ 172,000,000	93,000,000	127,000,000
Tax benefits realized from exercise of stock options	15,000,000	6,000,000	9,000,000
Intrinsic value of stock options exercised	$ 42,000,000	$ 17,000,000	$ 26,000,000

Stock-Based Compensation Pla104

Stock-Based Compensation Plans - Summary of Restricted Stock and Restricted Stock Unit Activity (Detail)	12 Months Ended
	Dec. 31, 2016$ / sharesshares
Restricted Stock Units (RSUs) [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted Stock Outstanding, Unvested, Beginning balance | shares	968,498
Restricted Stock Outstanding, Granted | shares	348,297
Restricted Stock Outstanding, Vested | shares	(570,509)
Restricted Stock Outstanding, Cancelled | shares	(6,936)
Restricted Stock Outstanding, Unvested, Ending balance | shares	739,350
Weighted-Average Grant Price, Unvested, Beginning balance | $ / shares	$ 109.38
Weighted-Average Grant Price, Granted | $ / shares	111.38
Weighted-Average Grant Price, Vested | $ / shares	108.21
Weighted-Average Grant Price, Cancelled | $ / shares	110.90
Weighted-Average Grant Price, Unvested, Ending balance | $ / shares	$ 111.21
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted Stock Outstanding, Unvested, Beginning balance | shares	625,888
Restricted Stock Outstanding, Granted | shares	218,341
Restricted Stock Outstanding, Vested | shares	(324,981)
Restricted Stock Outstanding, Cancelled | shares	(19,924)
Restricted Stock Outstanding, Unvested, Ending balance | shares	499,324
Weighted-Average Grant Price, Unvested, Beginning balance | $ / shares	$ 103.82
Weighted-Average Grant Price, Granted | $ / shares	110.31
Weighted-Average Grant Price, Vested | $ / shares	98.55
Weighted-Average Grant Price, Cancelled | $ / shares	108.15
Weighted-Average Grant Price, Unvested, Ending balance | $ / shares	$ 109.92

Stock-Based Compensation Pla105

Stock-Based Compensation Plans - Summary of Stock Option Activity (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Options Outstanding, Beginning balance | shares	4,223,710
Stock Options Outstanding, Granted | shares	200
Stock Options Outstanding, Exercised | shares	(1,694,440)
Stock Options Outstanding, Expired | shares	(934,879)
Stock Options Outstanding, Ending balance | shares	1,594,591
Stock Options Outstanding, Exercisable | shares	1,594,149
Weighted-Average Exercise Price, Outstanding, Beginning balance | $ / shares	$ 126.65
Weighted-Average Exercise Price, Granted | $ / shares	110.18
Weighted-Average Exercise Price, Exercised | $ / shares	106.68
Weighted-Average Exercise Price, Expired | $ / shares	140.75
Weighted-Average Exercise Price, Outstanding, Ending balance | $ / shares	139.60
Weighted-Average Exercise Price, Exercisable | $ / shares	$ 139.60
Weighted-Average Life (In Years), Outstanding, Ending balance	1 year 6 months
Weighted-Average Life (In Years), Exercisable	1 year 6 months
Aggregate Intrinsic Value, Outstanding, Ending balance | $	$ 39,326
Aggregate Intrinsic Value, Exercisable | $	$ 39,305

Pension Plans and Other Post106

Pension Plans and Other Postretirement Benefits - Net Periodic Benefit Cost for Defined Benefit Plans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 25,037	$ 24,372	$ 20,520
Interest cost on benefit obligation	83,410	72,731	69,162
Expected return on plan assets	(108,473)	(96,155)	(91,568)
Amortization of prior service credit	(3,228)	(6,005)	(6,552)
Recognized net actuarial loss	30,145	44,825	14,494
Net periodic benefit costs	26,891	39,768	6,056
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,595	914	605
Interest cost on benefit obligation	4,971	2,995	2,778
Amortization of prior service credit	(1,359)	(1,359)	(1,359)
Recognized net actuarial loss	60	106
Net periodic benefit costs	$ 5,267	$ 2,656	$ 2,024

Pension Plans and Other Post107

Pension Plans and Other Postretirement Benefits - Data Relating to Funding Position of Defined Benefit Plans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Change in plan assets:
Fair value of plan assets at beginning of year	$ 1,623,635
Fair value of plan assets at end of year	1,640,300	$ 1,623,635
Pension Benefits [Member]
Change in benefit obligation:
Benefit obligation at beginning of year	2,004,531	1,813,409
Service cost	25,037	24,372	$ 20,520
Interest cost	83,410	72,731	69,162
Amendments and curtailments	(28,308)
Actuarial (gain) loss	4,827	(83,593)
Business combinations		247,340
Benefits paid	(82,339)	(69,728)
Benefit obligation at end of year	2,007,158	2,004,531	1,813,409
Change in plan assets:
Fair value of plan assets at beginning of year	1,625,134	1,505,661
Actual return on plan assets	88,564	(14,069)
Employer contributions	10,772	8,367
Business combinations		194,903
Benefits paid	(82,339)	(69,728)
Fair value of plan assets at end of year	1,642,131	1,625,134	1,505,661
Funded status	(365,027)	(379,397)
Accrued liabilities recognized in the consolidated balance sheet	(365,027)	(379,397)
Net loss (gain)	460,562	494,279
Net prior service cost (credit)	3,505	277
Pre-tax adjustment to AOCI	464,067	494,556
Taxes	(182,611)	(194,608)
Net adjustment to AOCI	281,456	299,948
Other Postretirement Benefits [Member]
Change in benefit obligation:
Benefit obligation at beginning of year	121,497	67,502
Service cost	1,595	914	605
Interest cost	4,971	2,995	2,778
Plan participants’ contributions	3,085	2,619
Actuarial (gain) loss	(10,553)	(2,431)
Business combinations		56,539
Medicare Part D reimbursement	592	420
Benefits paid	(11,265)	(7,061)
Benefit obligation at end of year	109,922	121,497	$ 67,502
Change in plan assets:
Employer contributions	7,588	4,022
Plan participants’ contributions	3,085	2,619
Medicare Part D reimbursement	592	420
Benefits paid	(11,265)	(7,061)
Funded status	(109,922)	(121,497)
Accrued liabilities recognized in the consolidated balance sheet	(109,922)	(121,497)
Net loss (gain)	(6,413)	4,200
Net prior service cost (credit)	(7,737)	(9,096)
Pre-tax adjustment to AOCI	(14,150)	(4,896)
Taxes	5,568	1,927
Net adjustment to AOCI	$ (8,582)	$ (2,969)

Pension Plans and Other Post108

Pension Plans and Other Postretirement Benefits - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Minimum pension liability	$ 449,916,000
Minimum pension liability adjustment net of tax	272,874,000
Decrease in minimum liability adjustment		$ 39,743,000
Increase in minimum pension liability adjustment net of tax		24,105,000
Defined contribution pension and retirement savings plans total expense	$ 25,000,000	23,000,000	$ 22,000,000
Annual rate of increase in health care cost assumed for next fiscal year	6.50%
Defined Benefit Plan, ultimate health care cost trend rate	5.00%
Period for decreasing the annual rate	Over 12 years
Defined benefit pension plans	$ 234,969,000
Percentage of total assets	14.30%
Defined benefit plan fair value of plan assets	$ 1,640,300,000	1,623,635,000
Qualified benefit pension plans	$ 0	0
Percentage of pension plan assets that is not exceeded by investment in security of single Non-US Government of Government agency	10.00%
Percentage of eligible employees contribution for Retirement Savings Plan	50.00%
Percentage of employer matching contribution to employee's contribution	75.00%
Maximum employer contribution on Employee's qualified contribution	4.50%
Qualified defined contribution plans expense during the period	$ 36,766,000	34,145,000	32,466,000
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocations for plan assets, minimum range	25.00%
Target allocations for plan assets, maximum range	60.00%
Defined benefit plan fair value of plan assets	$ 920,077,000	1,059,758,000
Total Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocations for plan assets, minimum range	10.00%
Target allocations for plan assets, maximum range	65.00%
Defined benefit plan fair value of plan assets	$ 445,698,000	284,365,000
Other Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocations for plan assets, minimum range	10.00%
Target allocations for plan assets, maximum range	85.00%
Defined benefit plan fair value of plan assets	$ 234,969,000	209,878,000
M&T Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	$ 164,474,000	$ 148,800,000
Percentage of common stock in total plan assets	10.00%	9.20%
Supplemental Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 160,433,000
Accumulated benefit obligation		$ 161,657,000
Employer contributions	10,772,000	8,367,000
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	2,007,158,000	2,004,531,000	1,813,409,000
Accumulated benefit obligation	1,979,225,000	1,951,425,000
Minimum pension liability	464,066,000
Defined benefit plan fair value of plan assets	1,642,131,000	1,625,134,000	1,505,661,000
Employer contributions	10,772,000	8,367,000
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	109,922,000	121,497,000	$ 67,502,000
Minimum pension liability	14,150,000
Employer contributions	$ 7,588,000	$ 4,022,000

Pension Plans and Other Post109

Pension Plans and Other Postretirement Benefits - Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Net loss (gain)	$ 14,183	$ 24,200
Amendments and curtailments	(28,308)
Amortization of prior service credit	4,587	7,364	$ 7,911
Amortization of actuarial loss	(30,205)	(44,931)	$ (14,494)
Total recognized in other comprehensive income, pre-tax	(39,743)	(13,367)
Pension Benefits [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Net loss (gain)	24,736	26,631
Amendments and curtailments	(28,308)
Amortization of prior service credit	3,228	6,005
Amortization of actuarial loss	(30,145)	(44,825)
Total recognized in other comprehensive income, pre-tax	(30,489)	(12,189)
Other Postretirement Benefits [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Net loss (gain)	(10,553)	(2,431)
Amortization of prior service credit	1,359	1,359
Amortization of actuarial loss	(60)	(106)
Total recognized in other comprehensive income, pre-tax	$ (9,254)	$ (1,178)

Pension Plans and other Post110

Pension Plans and other Postretirement Benefits - Amortization of Amounts in Accumulated Other Comprehensive Income Expected to be Recognized as Components of Net Periodic Benefit Expense (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)
Pension Benefits [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Amortization of net prior service cost (credit)	$ 557
Amortization of net loss (gain)	27,196
Other Postretirement Benefits [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Amortization of net prior service cost (credit)	(1,359)
Amortization of net loss (gain)	$ (44)

Pension Plans and Other Post111

Pension Plans and Other Postretirement Benefits - Assumed Weighted-Average Rates Used to Determine Benefit Obligations (Detail)	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Discount rate	4.00%	4.25%
Rate of increase in future compensation levels	4.39%	4.37%
Other Postretirement Benefits [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Discount rate	4.00%	4.25%

Pension Plans and Other Post112

Pension Plans and Other Postretirement Benefits - Assumed Weighted-Average Rates Used to Determine Net Benefit Expense (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Discount rate	4.25%	4.00%	4.75%
Long-term rate of return on plan assets	6.50%	6.50%	6.50%
Rate of increase in future compensation levels	4.37%	4.39%	4.42%
Other Postretirement Benefits [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Discount rate	4.25%	4.00%	4.75%

Pension Plans and Other Post113

Pension Plans and Other Postretirement Benefits - Effects on One-Percentage Point Change in Assumed Health Care Cost Trend Rates (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)
Compensation And Retirement Disclosure [Abstract]
Service and interest cost	$ 106
Accumulated postretirement benefit obligation	1,548
Service and interest cost	(87)
Accumulated postretirement benefit obligation	$ (1,400)

Pension Plans and Other Post114

Pension Plans and Other Postretirement Benefits - Fair Values of Company's Pension Plan Assets by Asset Category (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	$ 1,640,300	$ 1,623,635
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	1,340,215	1,300,948
Significant Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	243,845	265,013
Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	56,240	57,674
Money-Market Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	39,556	69,634
Money-Market Funds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	35,562	37,958
Money-Market Funds [Member] | Significant Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	3,994	31,676
M&T Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	164,474	148,800
M&T Equity Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	164,474	148,800
Domestic Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	200,595	106,993
Domestic Equity Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	200,595	106,993
International Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	14,364	9,433
International Equity Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	14,364	9,433
Domestic Mutual Fund Equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	250,472	445,663
Domestic Mutual Fund Equity securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	250,472	445,663
International Mutual Fund Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	290,172	348,869
International Mutual Fund Equity Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	290,172	348,869
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	920,077	1,059,758
Equity Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	920,077	1,059,758
Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	104,909	105,499
Corporate Debt Securities [Member] | Significant Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	104,909	105,499
Government Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	121,869	120,346
Government Debt Securities [Member] | Significant Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	121,869	120,346
International Debt securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	13,073	7,492
International Debt securities [Member] | Significant Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	13,073	7,492
Domestic Mutual Fund Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	205,847	51,028
Domestic Mutual Fund Debt Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	205,847	51,028
Total Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	445,698	284,365
Total Debt Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	205,847	51,028
Total Debt Securities [Member] | Significant Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	239,851	233,337
Other Diversified Mutual Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	92,691	70,343
Other Diversified Mutual Fund [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	92,691	70,343
Other Real Estate Partnerships [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	3,112	2,787
Other Real Estate Partnerships [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	768
Other Real Estate Partnerships [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	2,344	2,787
Other Private Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	21,924	5,603
Other Private Equity [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	21,924	5,603
Other Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	106,250	119,549
Other Hedge Funds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	85,270	81,861
Other Hedge Funds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	20,980	37,688
Guaranteed Deposit Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	10,992	11,596
Guaranteed Deposit Fund [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	10,992	11,596
Other Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	234,969	209,878
Other Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	178,729	152,204
Other Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of plan assets	$ 56,240	$ 57,674

Pension Plans and Other Post115

Pension Plans and Other Postretirement Benefits - Fair Values of Company's Pension Plan Assets by Asset Category (Parenthetical) (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Interest and dividend receivable on plan assets	$ 1,831,000	$ 1,499,000
Investment Grade Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Investment in mutual funds	75.00%	33.00%
High-Yielding Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Investment in mutual funds	25.00%	67.00%

Pension Plans and Other Post116

Pension Plans and Other Postretirement Benefits - Changes in Level 3 Pension Plan Assets Measured at Fair Value on Recurring Basis (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	$ 1,623,635
Fair value of plan assets at end of year	1,640,300
Significant Unobservable Inputs (Level 3) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	57,674
Fair value of plan assets at end of year	56,240
Other Private Real Estate [Member] | Significant Unobservable Inputs (Level 3) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	2,787
Purchase(Sales)	(1,111)
Total Realized/Unrealized Gains (Losses)	668
Fair value of plan assets at end of year	2,344
Other Private Equity [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	5,603
Fair value of plan assets at end of year	21,924
Other Private Equity [Member] | Significant Unobservable Inputs (Level 3) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	5,603
Purchase(Sales)	17,177
Total Realized/Unrealized Gains (Losses)	(856)
Fair value of plan assets at end of year	21,924
Other Hedge Funds [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	119,549
Fair value of plan assets at end of year	106,250
Other Hedge Funds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	37,688
Purchase(Sales)	(16,337)
Total Realized/Unrealized Gains (Losses)	(371)
Fair value of plan assets at end of year	20,980
Guaranteed Deposit Fund [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	11,596
Fair value of plan assets at end of year	10,992
Guaranteed Deposit Fund [Member] | Significant Unobservable Inputs (Level 3) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	11,596
Purchase(Sales)	(540)
Total Realized/Unrealized Gains (Losses)	(64)
Fair value of plan assets at end of year	10,992
Other Securities [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	209,878
Fair value of plan assets at end of year	234,969
Other Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Fair value of plan assets at beginning of year	57,674
Purchase(Sales)	(811)
Total Realized/Unrealized Gains (Losses)	(623)
Fair value of plan assets at end of year	$ 56,240

Pension Plans and Other Post117

Pension Plans and Other Postretirement Benefits - Defined Benefit Plan Estimated Future Benefit Payments (Detail) $ in Thousands	Dec. 31, 2016USD ($)
Pension Benefits [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
2,017	$ 81,927
2,018	85,715
2,019	91,819
2,020	96,465
2,021	101,698
2022 through 2026	568,830
Other Postretirement Benefits [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
2,017	8,142
2,018	8,220
2,019	8,251
2,020	8,259
2,021	8,235
2022 through 2026	$ 40,282

Income Taxes - Components of In

Income Taxes - Components of Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current
Federal	$ 428,750	$ 130,349	$ 378,978
State and city	95,426	21,549	50,790
Total current	524,176	151,898	429,768
Deferred
Federal	147,662	324,317	65,503
State and city	26,351	72,279	27,345
Total deferred	174,013	396,596	92,848
Amortization of investments in qualified affordable housing projects	45,095	46,531	53,383
Income taxes	$ 743,284	$ 595,025	$ 575,999

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016USD ($)State	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Income Tax Disclosure [Abstract]
Tax bad debt reserve	$ 137,121,000
Income taxes attributable to gains or losses on bank investment securities	11,929,000	$ 0	$ 0
Minimum alternative tax expense recognized for gains or losses on bank investment securities	$ 0	$ 0	$ 0
Number of state and local jurisdictions where company files income tax returns | State	40

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income Taxes Expenses Benefit Reconciliation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income taxes at statutory federal income tax rate	$ 720,439	$ 586,142	$ 574,786
Increase (decrease) in taxes:
Tax-exempt income	(35,364)	(33,102)	(31,752)
State and city income taxes, net of federal income tax effect	79,155	60,988	50,788
Qualified affordable housing project federal tax credits, net	(15,091)	(15,297)	(14,827)
Other	(5,855)	(3,706)	(2,996)
Income taxes	$ 743,284	$ 595,025	$ 575,999

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets (Liabilities) (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Losses on loans and other assets	$ 590,288	$ 637,955	$ 605,273
Retirement benefits	143,067	148,722	120,222
Postretirement and other employee benefits	52,512	55,962	34,052
Incentive and other compensation plans	36,616	60,337	36,450
Interest on loans	61,266	57,640	79,147
Stock-based compensation	52,181	72,090	64,017
Unrealized investment losses	10,741
Depreciation and amortization			3,527
Other	106,876	162,086	100,999
Gross deferred tax assets	1,053,547	1,194,792	1,043,687
Leasing transactions	(266,268)	(285,074)	(280,596)
Unrealized investment gains		(31,121)	(82,065)
Capitalized servicing rights	(71,108)	(59,171)	(46,393)
Depreciation and amortization	(63,959)	(56,731)
Other	(87,200)	(55,611)	(66,939)
Gross deferred tax liabilities	(488,535)	(487,708)	(475,993)
Net deferred tax asset	$ 565,012	$ 707,084	$ 567,694

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Federal, State and Local Tax [Member]
Reconciliation Of Unrecognized Tax Benefits [Line Items]
Beginning Balance	$ 24,537	$ 10,712	$ 14,611
Increases as a result of tax positions taken during the period	12,237	8,108	769
Decreases as a result of settlements with taxing authorities		(1,515)	(4,668)
Unrealized tax benefits acquired in a business combination		7,232
Decreases as a result of tax positions taken in prior years	(885)
Ending Balance	35,889	24,537	10,712
Accrued Interest [Member]
Reconciliation Of Unrecognized Tax Benefits [Line Items]
Beginning Balance	7,969	3,869	14,696
Increases as a result of tax positions taken in prior years	656	807	453
Decreases as a result of settlements with taxing authorities		(274)	(11,280)
Unrealized tax benefits acquired in a business combination		3,567
Decreases as a result of tax positions taken in prior years	(710)
Ending Balance	7,915	7,969	3,869
Unrecognized Income Tax Benefits [Member]
Reconciliation Of Unrecognized Tax Benefits [Line Items]
Beginning Balance	32,506	14,581	29,307
Increases as a result of tax positions taken during the period	12,237	8,108	769
Increases as a result of tax positions taken in prior years	656	807	453
Decreases as a result of settlements with taxing authorities		(1,789)	(15,948)
Unrealized tax benefits acquired in a business combination		10,799
Decreases as a result of tax positions taken in prior years	(1,595)
Ending Balance	43,804	$ 32,506	$ 14,581
Less: Federal, state and local income tax benefits	(15,332)
Net unrecognized tax benefits that, if recognized, would impact the effective income tax rate	$ 28,472

Earnings Per Common Share - Com

Earnings Per Common Share - Computations of Basic Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income available to common shareholders:
Net income	$ 1,315,114	$ 1,079,667	$ 1,066,246
Less: Preferred stock dividends	(81,270)	(81,270)	(75,878)
Net income available to common equity	1,233,844	998,397	990,368
Less: Income attributable to unvested stock-based compensation awards	(10,385)	(10,708)	(11,837)
Net income available to common shareholders	$ 1,223,459	$ 987,689	$ 978,531
Weighted-average shares outstanding:
Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards	158,121	138,285	132,532
Less: Unvested stock-based compensation awards	(1,341)	(1,482)	(1,582)
Weighted-average shares outstanding	156,780	136,803	130,950
Basic earnings per common share	$ 7.80	$ 7.22	$ 7.47

Earnings Per Common Share - 124

Earnings Per Common Share - Computations of Diluted Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Net income available to common equity	$ 1,233,844	$ 998,397	$ 990,368
Less: Income attributable to unvested stock-based compensation awards	(10,363)	(10,673)	(11,787)
Net income available to common shareholders	$ 1,223,481	$ 987,724	$ 978,581
Adjusted weighted-average shares outstanding:
Common and unvested stock-based compensation awards	158,121	138,285	132,532
Less: Unvested stock-based compensation awards	(1,341)	(1,482)	(1,582)
Plus: Incremental shares from assumed conversion of stock-based compensation awards and warrants to purchase common stock	524	730	894
Adjusted weighted-average shares outstanding	157,304	137,533	131,844
Diluted earnings per common share	$ 7.78	$ 7.18	$ 7.42

Earnings Per Common Share - Add

Earnings Per Common Share - Additional Information (Detail) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Antidilutive securities excluded from computation of earnings per share	2,171,000	2,268,000	2,017,000

Comprehensive Income - Componen

Comprehensive Income - Components of Other Comprehensive Income (Loss) and Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) to Net Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, before tax	$ (414,545)	$ (297,843)	$ (105,797)
Unrealized holding gains (losses), before tax	(79,950)	(133,702)	150,187
Foreign currency translation adjustment, before tax	(4,020)	(1,323)	(4,039)
Unrealized Gains (losses) on cash flow hedges, before tax		1,453	(165)
Current year benefit plans gains (losses), before tax	14,125	(24,200)	(347,993)
Total other comprehensive income (loss) before reclassifications, before tax	(69,845)	(157,772)	(202,010)
Amortization of unrealized holding losses on held-to-maturity ("HTM") securities, before tax	3,996	3,514	3,374
Gains (losses) realized in net income, before tax	(30,314)	130
Accretion of net gain (losses) on terminated cash flow hedges, before tax	(155)	(141)	7
Amortization of prior service credit, before tax	(4,587)	(7,364)	(7,911)
Amortization of actuarial losses, before tax	30,205	44,931	14,494
Total reclassifications, before tax	(855)	41,070	9,964
Total gain (loss) during the period, before tax	(70,700)	(116,702)	(192,046)
Ending balance, before tax	(485,245)	(414,545)	(297,843)
Beginning balance, tax	162,918	116,849	41,638
Unrealized holding gains (losses), tax	31,509	52,376	(58,962)
Foreign currency translation adjustment, tax	1,406	398	1,432
Unrealized Gains (losses) on cash flow hedges, tax		(572)	65
Current year benefit plans gains (losses), tax	(5,557)	8,612	136,587
Total other comprehensive income (loss) before reclassifications, tax	27,358	60,814	79,122
Amortization of unrealized holding losses on held-to-maturity ("HTM") securities, tax	(1,572)	(1,383)	(1,324)
Gains (losses) realized in net income, tax	11,925	(49)
Accretion of net gain (losses) on terminated cash flow hedges, tax	61	56	(3)
Amortization of prior service credit, tax	1,805	2,620	3,105
Amortization of actuarial losses, tax	(11,886)	(15,989)	(5,689)
Total reclassifications, tax	333	(14,745)	(3,911)
Total gain (loss) during the period, tax	27,691	46,069	75,211
Ending balance, tax	190,609	162,918	116,849
Beginning balance, net of tax	(251,627)	(180,994)	(64,159)
Unrealized holding gains (losses), net of tax	(48,441)	(81,326)	91,225
Foreign currency translation adjustment, net of tax	(2,614)	(925)	(2,607)
Unrealized Gains (losses) on cash flow hedges, net of tax		881	(100)
Current year benefit plans gains (losses), net of tax	8,568	(15,588)	(211,406)
Total other comprehensive income (loss) before reclassifications, net of tax	(42,487)	(96,958)	(122,888)
Amortization of unrealized holding losses on held-to-maturity ("HTM") securities, net of tax	2,424	2,131	2,050
Gains (losses) realized in net income, net of tax	(18,389)	81
Accretion of net gain on terminated cash flow hedges, net of tax	(94)	(85)	4
Amortization of prior service credit, net of tax	(2,782)	(4,744)	(4,806)
Amortization of actuarial losses, net of tax	18,319	28,942	8,805
Total reclassifications, net of tax	(522)	26,325	6,053
Total other comprehensive loss	(43,009)	(70,633)	(116,835)
Ending balance, net of tax	(294,636)	(251,627)	(180,994)
Investment Securities With OTTI [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, before tax	16,359	7,438	37,255
Unrealized holding gains (losses), before tax	30,366	8,921	(29,818)
Total other comprehensive income (loss) before reclassifications, before tax	30,366	8,921	(29,818)
Amortization of unrealized holding losses on held-to-maturity ("HTM") securities, before tax			1
Total reclassifications, before tax			1
Total gain (loss) during the period, before tax	30,366	8,921	(29,817)
Ending balance, before tax	46,725	16,359	7,438
Investment Securities All Other [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, before tax	62,849	201,828	18,450
Unrealized holding gains (losses), before tax	(110,316)	(142,623)	180,005
Total other comprehensive income (loss) before reclassifications, before tax	(110,316)	(142,623)	180,005
Amortization of unrealized holding losses on held-to-maturity ("HTM") securities, before tax	3,996	3,514	3,373
Gains (losses) realized in net income, before tax	(30,314)	130
Total reclassifications, before tax	(26,318)	3,644	3,373
Total gain (loss) during the period, before tax	(136,634)	(138,979)	183,378
Ending balance, before tax	(73,785)	62,849	201,828
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, before tax	(489,660)	(503,027)	(161,617)
Current year benefit plans gains (losses), before tax	14,125	(24,200)	(347,993)
Total other comprehensive income (loss) before reclassifications, before tax	14,125	(24,200)	(347,993)
Amortization of prior service credit, before tax	(4,587)	(7,364)	(7,911)
Amortization of actuarial losses, before tax	30,205	44,931	14,494
Total reclassifications, before tax	25,618	37,567	6,583
Total gain (loss) during the period, before tax	39,743	13,367	(341,410)
Ending balance, before tax	(449,917)	(489,660)	(503,027)
Total other comprehensive loss	24,105	8,610	(207,407)
Other [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, before tax	(4,093)	(4,082)	115
Foreign currency translation adjustment, before tax	(4,020)	(1,323)	(4,039)
Unrealized Gains (losses) on cash flow hedges, before tax		1,453	(165)
Total other comprehensive income (loss) before reclassifications, before tax	(4,020)	130	(4,204)
Accretion of net gain (losses) on terminated cash flow hedges, before tax	(155)	(141)	7
Total reclassifications, before tax	(155)	(141)	7
Total gain (loss) during the period, before tax	(4,175)	(11)	(4,197)
Ending balance, before tax	$ (8,268)	$ (4,093)	$ (4,082)

Comprehensive Income - Accumula

Comprehensive Income - Accumulated Other Comprehensive Income (Loss), Net (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 16,173,289	$ 12,335,896	$ 11,305,532
Net gain (loss) during period	(43,009)	(70,633)	(116,835)
Ending balance	16,486,622	16,173,289	12,335,896
Investment securities With OTTI [Member] | Investment Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	9,921	4,518	22,632
Net gain (loss) during period	18,417	5,403	(18,114)
Ending balance	28,338	9,921	4,518
Investment securities All Other [Member] | Investment Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	38,166	122,683	11,294
Net gain (loss) during period	(82,823)	(84,517)	111,389
Ending balance	(44,657)	38,166	122,683
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(296,979)	(305,589)	(98,182)
Net gain (loss) during period	24,105	8,610	(207,407)
Ending balance	(272,874)	(296,979)	(305,589)
Accumulated Other Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(2,735)	(2,606)	97
Net gain (loss) during period	(2,708)	(129)	(2,703)
Ending balance	(5,443)	(2,735)	(2,606)
Accumulated Other Comprehensive Income (Loss), Net [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(251,627)	(180,994)	(64,159)
Net gain (loss) during period	(43,009)	(70,633)	(116,835)
Ending balance	$ (294,636)	$ (251,627)	$ (180,994)

Other Income and Other Expen128

Other Income and Other Expense - Other Income and Other Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other income:
Credit-related fee income	$ 70,424	$ 81,558	$ 72,454
Letter of credit fees		52,724	56,708
Bank owned life insurance		52,984	50,004
Other expense:
Professional services	268,060	267,540	324,460
Amortization of capitalized servicing rights	$ 50,982	$ 49,906	$ 68,410

International Activities - Addi

International Activities - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
International Activities [Line Items]
Revenues from international trust-related services	$ 25,000	$ 26,000	$ 31,000
Loans to foreign borrowers	89,864,419	86,533,507
Deposits at foreign office	201,927	170,170
Cayman Islands [Member]
International Activities [Line Items]
Deposits at foreign office	201,927	170,170
Canada [Member]
International Activities [Line Items]
Deposits at foreign office	50,000	35,000
Geographic Distribution, Foreign [Member]
International Activities [Line Items]
Loans to foreign borrowers	$ 292,000	$ 265,000
Geographic Concentration Risk [Member] | Assets, Total [Member]
International Activities [Line Items]
Concentration risk percentage	1.00%
Geographic Concentration Risk [Member] | Sales Revenue, Net [Member]
International Activities [Line Items]
Concentration risk percentage	1.00%

Derivative Financial Instrum130

Derivative Financial Instruments - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative [Line Items]
Net unrealized pre-tax gains related to hedged loans held for sale, commitments to originate loans for sale and commitments to sell loans	$ 28,000,000	$ 18,000,000
Aggregate fair value of derivative financial instruments in a liability position	34,000,000	59,000,000
Net liability positions with counterparties	30,000,000	55,000,000
Aggregate fair value of derivative financial instruments in asset position	15,000,000	23,000,000
Net fair value of derivative financial instruments in a net asset position	11,000,000	19,000,000
Collateral relating to net asset positions	9,000,000	22,000,000
Counterparties [Member]
Derivative [Line Items]
Post collateral requirements relating to positions	27,000,000	52,000,000
Clearinghouse Credit Facilities [Member]
Derivative [Line Items]
Post collateral requirements relating to positions		47,000,000
Aggregate fair value of derivative financial instruments in a net liability position		50,000,000
Net fair value of derivative financial instruments in a net asset position	63,000,000
Collateral relating to net asset positions	81,000,000
Amount of initial margin posted	111,000,000	52,000,000
Interest Rate Swap Agreements [Member]
Derivative [Line Items]
Increase in net interest income due to interest rate swap agreements	37,000,000	44,000,000	$ 45,000,000
Average notional amounts of interest rate swap agreements impacting net interest income, contract entered into for interest rate risk management purposes	1,400,000,000	1,400,000,000	$ 1,400,000,000
Notional amounts of derivative contracts entered into for trading account purposes	900,000,000
Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amounts of derivative contracts entered into for trading account purposes	21,600,000,000	18,400,000,000
Foreign Currency and Other Option and Futures Contracts [Member]
Derivative [Line Items]
Notional amounts of derivative contracts entered into for trading account purposes	471,000,000,000	$ 1,600,000,000
Credit Risk Derivative [Member]
Derivative [Line Items]
Aggregate fair value of derivative financial instruments in a net liability position	2,000,000
Fair value of additional collateral to be posted for derivative financial instruments	$ 2,000,000

Derivative Financial Instrum131

Derivative Financial Instruments - Information about Interest Rate Swap Agreements (Detail) - Fixed Rate Long-Term Borrowings [Member] - Fair Value Hedges [Member] - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Notional Amount	$ 900,000,000	$ 1,400,000,000
Average Maturity (in years)	1 year 1 month 6 days	1 year 8 months 12 days
Weighted-Average Rate, Fixed	3.75%	4.42%
Weighted-Average Rate, Variable	2.08%	1.39%
Estimated Fair Value Gain	$ 11,892,000	$ 43,892,000

Derivative Financial Instrum132

Derivative Financial Instruments - Notional Amount of Interest Rate Swap Agreements Outstanding Maturity (Detail) - Interest Rate Swap Agreements [Member]	Dec. 31, 2016USD ($)
Derivative Instruments And Hedging Activities Disclosures [Line Items]
2,017	$ 400,000,000
2,018	500,000,000
Total	$ 900,000,000

Derivative Financial Instrum133

Derivative Financial Instruments - Information about Fair Values of Derivative Instruments in Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	$ 295,069	$ 268,637
Liability Derivatives, Fair Value	176,857	162,650
Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	249,988	222,901
Liability Derivatives, Fair Value	175,510	161,994
Fair Value Hedges [Member] | Derivatives Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	45,081	45,736
Liability Derivatives, Fair Value	1,347	656
Interest Rate Swap Agreements [Member] | Fair Value Hedges [Member] | Derivatives Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	11,892	43,892
Commitments to Sell Real Estate Loans [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	5,210	533
Liability Derivatives, Fair Value	399	846
Commitments to Sell Real Estate Loans [Member] | Fair Value Hedges [Member] | Derivatives Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	33,189	1,844
Liability Derivatives, Fair Value	1,347	656
Mortgage-Related Commitments to Originate Real Estate Loans for Sale [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	8,060	10,282
Liability Derivatives, Fair Value	735	403
Interest Rate Contracts [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	228,810	203,517
Liability Derivatives, Fair Value	167,737	153,723
Foreign Exchange and Other Option and Futures Contracts [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	7,908	8,569
Liability Derivatives, Fair Value	$ 6,639	$ 7,022

Derivative Financial Instrum134

Derivative Financial Instruments - Information about Fair Values of Derivative Instruments in Consolidated Statement of Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives not designated as hedging instruments, Derivatives	$ 21,707	$ 20,092	$ 11,068
Interest Rate Swap Agreements [Member] | Fixed Rate Long-Term Borrowings [Member] | Derivatives Designated and Qualifying as Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives in fair value hedging relationships, Derivatives	(32,000)	(29,359)	(29,624)
Derivatives in fair value hedging relationships, Hedged item	30,906	28,719	28,870
Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives not designated as hedging instruments, Derivatives	14,042	10,755	3,398
Foreign Exchange and Other Option and Futures Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives not designated as hedging instruments, Derivatives	$ 7,665	$ 9,337	$ 7,670

Variable Interest Entities a135

Variable Interest Entities and Asset Securitizations - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Variable Interest Entity Disclosure [Abstract]
Carrying value of loans in the Securitization trusts		$ 81,000,000
Combined outstanding principal amount of mortgage-backed securities issued by qualified special purpose trust held by unrelated parties		13,000,000
Residential mortgage loans securitized with Ginnie Mae	$ 24,000,000	65,000,000	$ 135,000,000
Other assets for its "investment" in the common securities recognized by the company of various trusts	24,000,000	24,000,000
Total assets of partnerships in which the company invested	1,000,000,000	1,100,000,000
Maximum exposure to loss of investments in real estate partnerships	294,000,000	295,000,000
Unfunded commitments included in company's maximum exposure to loss of investments in real estate partnerships	$ 102,000,000	$ 78,000,000

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities issued by financial institutions and other entities backed by trust preferred securities at cost		$ 28
Fair value of securities issued by financial institutions and other entities backed by trust preferred securities		47
Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Change in fair value of nonrecurring fair value measured loans for charge-offs and impairment reserves	$ 71	75	$ 55
Fair Value, Measurements, Nonrecurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loans measured at fair value on nonrecurring basis	293	210	173
Assets taken in foreclosure of defaulted loans measured at fair value on a nonrecurring basis	56	29
Fair Value, Measurements, Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loans measured at fair value on nonrecurring basis	153	106	94
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loans measured at fair value on nonrecurring basis	$ 140	$ 104	$ 79
Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount margin over LIBOR	4.00%
Discount rates for fair value estimations	15.00%
Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount margin over LIBOR	10.00%
Discount rates for fair value estimations	90.00%
Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount margin over LIBOR	8.00%

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Estimated Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets	$ 323,867	$ 273,783
Investment securities	13,332,072	12,242,671
U.S. Treasury and Federal Agencies [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	1,902,544	299,997
Obligations of States and Political Subdivisions [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	3,641	6,028
Government Issued or Guaranteed [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	10,954,861	11,686,628
Collateralized Debt Obligations [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities		47,393
Other Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	118,516	118,880
Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	352,466	83,671
Fair Value Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets	323,867	273,783
Investment securities	13,332,072	12,242,671
Real estate loans held for sale	1,056,180	392,036
Other assets	58,351	56,551
Total assets	14,770,470	12,965,041
Trading account liabilities	174,376	160,745
Other liabilities	2,481	1,905
Total liabilities	176,857	162,650
Fair Value Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets	46,135	56,763
Investment securities	301,711	65,178
Total assets	347,846	121,941
Fair Value Measurements, Recurring [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets	277,732	217,020
Investment securities	13,030,317	12,130,026
Real estate loans held for sale	1,056,180	392,036
Other assets	50,291	46,269
Total assets	14,414,520	12,785,351
Trading account liabilities	174,376	160,745
Other liabilities	1,746	1,502
Total liabilities	176,122	162,247
Fair Value Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	44	47,467
Other assets	8,060	10,282
Total assets	8,104	57,749
Other liabilities	735	403
Total liabilities	735	403
Fair Value Measurements, Recurring [Member] | U.S. Treasury and Federal Agencies [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	1,902,544	299,997
Fair Value Measurements, Recurring [Member] | U.S. Treasury and Federal Agencies [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	1,902,544	299,997
Fair Value Measurements, Recurring [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	3,641	6,028
Fair Value Measurements, Recurring [Member] | Obligations of States and Political Subdivisions [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	3,641	6,028
Fair Value Measurements, Recurring [Member] | Government Issued or Guaranteed [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	10,954,861	11,686,628
Fair Value Measurements, Recurring [Member] | Government Issued or Guaranteed [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	10,954,861	11,686,628
Fair Value Measurements, Recurring [Member] | Privately Issued Mortgage-Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	44	74
Fair Value Measurements, Recurring [Member] | Privately Issued Mortgage-Backed Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	44	74
Fair Value Measurements, Recurring [Member] | Collateralized Debt Obligations [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities		47,393
Fair Value Measurements, Recurring [Member] | Collateralized Debt Obligations [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities		47,393
Fair Value Measurements, Recurring [Member] | Other Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	118,516	118,880
Fair Value Measurements, Recurring [Member] | Other Debt Securities [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	118,516	118,880
Fair Value Measurements, Recurring [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	352,466	83,671
Fair Value Measurements, Recurring [Member] | Equity Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	301,711	65,178
Fair Value Measurements, Recurring [Member] | Equity Securities [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	$ 50,755	$ 18,493

Fair Value Measurements - Chang

Fair Value Measurements - Changes in Level 3 Assets and Liabilities Measured at Estimated Fair Value on Recurring Basis (Detail) - Fair Value Measurements, Recurring [Member] - Significant Unobservable Inputs (Level 3) [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Privately Issued [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 74	$ 103	$ 1,850
Total gains (losses) realized/unrealized:
Included in other comprehensive income			271
Settlements	(30)	(29)	(2,018)
Ending Balance	44	74	103
Collateralized Debt Obligations [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	47,393	50,316	63,083
Total gains (losses) realized/unrealized:
Included in earnings	30,041
Included in other comprehensive income	(18,268)	3,254	8,209
Sales	(58,296)
Settlements	(870)	(6,177)	(20,976)
Ending Balance		47,393	50,316
Other Assets and Other Liabilities [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	9,879	17,347	3,941
Total gains (losses) realized/unrealized:
Included in earnings	110,937	87,061	83,417
Transfers out of Level 3(a)	(113,491)	(94,529)	(70,011)
Ending Balance	7,325	9,879	17,347
Changes in unrealized gains included in earnings related to assets still held at end of period	$ 7,256	$ 8,850	$ 18,196

Fair Value Measurements - Quant

Fair Value Measurements - Quantitative Information Related to Significant Unobservable Inputs (Detail) - Fair Value Measurements, Recurring [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Privately Issued [Member] | Two Independent Pricing Quotes [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Recurring fair value measurements for certain Level 3 Assets and Liabilities	$ 44	$ 74
Collateralized Debt Obligations [Member] | Discounted Cash Flows [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Recurring fair value measurements for certain Level 3 Assets and Liabilities		$ 47,393
Loss severity		100.00%
Collateralized Debt Obligations [Member] | Discounted Cash Flows [Member] | Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Probability of default		10.00%
Collateralized Debt Obligations [Member] | Discounted Cash Flows [Member] | Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Probability of default		56.00%
Collateralized Debt Obligations [Member] | Discounted Cash Flows [Member] | Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Probability of default		31.00%
Other Assets and Other Liabilities [Member] | Discounted Cash Flows [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Recurring fair value measurements for certain Level 3 Assets and Liabilities	$ 7,325	$ 9,879
Other Assets and Other Liabilities [Member] | Discounted Cash Flows [Member] | Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Commitment expirations	0.00%	0.00%
Other Assets and Other Liabilities [Member] | Discounted Cash Flows [Member] | Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Commitment expirations	77.00%	60.00%
Other Assets and Other Liabilities [Member] | Discounted Cash Flows [Member] | Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Commitment expirations	30.00%	39.00%

Fair Value Measurements - Carry

Fair Value Measurements - Carrying Amounts and Estimated Fair Value for Financial Instrument Assets (Liabilities) (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financial assets:
Cash and cash equivalents	$ 1,320,549	$ 1,368,040	$ 1,373,357	$ 1,672,934
Interest-bearing deposits at banks	5,000,638	7,594,350
Trading account assets	323,867	273,783
Investment securities	16,250,468	15,656,439
Loans and leases:
Residential real estate loans	22,584,141	26,249,059
Consumer loans	12,130,094	11,584,347
Allowance for credit losses	(988,997)	(955,992)	$ (919,562)	$ (916,676)
Loans and leases, net	89,864,419	86,533,507
Financial liabilities:
Noninterest-bearing deposits	(32,813,896)	(29,110,635)
Savings and interest-checking deposits	(52,346,207)	(49,566,644)
Time deposits	(10,131,846)	(13,110,392)
Deposits at Cayman Islands office	(201,927)	(170,170)
Short-term borrowings	(163,442)	(150,546)
Long-term borrowings	(9,493,835)	(10,653,858)
Carrying Amount [Member]
Financial assets:
Cash and cash equivalents	1,320,549	1,368,040
Interest-bearing deposits at banks	5,000,638	7,594,350
Trading account assets	323,867	273,783
Investment securities	16,250,468	15,656,439
Loans and leases:
Commercial loans and leases	22,610,047	20,422,338
Commercial real estate loans	33,506,394	29,197,311
Residential real estate loans	22,590,912	26,270,103
Consumer loans	12,146,063	11,599,747
Allowance for credit losses	(988,997)	(955,992)
Loans and leases, net	89,864,419	86,533,507
Accrued interest receivable	308,805	306,496
Financial liabilities:
Noninterest-bearing deposits	(32,813,896)	(29,110,635)
Savings and interest-checking deposits	(52,346,207)	(49,566,644)
Time deposits	(10,131,846)	(13,110,392)
Deposits at Cayman Islands office	(201,927)	(170,170)
Short-term borrowings	(163,442)	(2,132,182)
Long-term borrowings	(9,493,835)	(10,653,858)
Accrued interest payable	(75,172)	(85,145)
Trading account liabilities	(174,376)	(160,745)
Other financial instruments:
Commitments to originate real estate loans for sale	7,325	9,879
Commitments to sell real estate loans	36,653	875
Other credit-related commitments	(136,295)	(122,334)
Interest rate swap agreements used for interest rate risk management	11,892	43,892
Estimate Fair Value [Member]
Financial assets:
Cash and cash equivalents	1,320,549	1,368,040
Interest-bearing deposits at banks	5,000,638	7,594,350
Trading account assets	323,867	273,783
Investment securities	16,244,412	15,660,877
Loans and leases:
Commercial loans and leases	22,239,428	20,146,201
Commercial real estate loans	33,129,428	29,044,244
Residential real estate loans	22,638,167	26,267,771
Consumer loans	12,061,590	11,550,270
Loans and leases, net	90,068,613	87,008,486
Accrued interest receivable	308,805	306,496
Financial liabilities:
Noninterest-bearing deposits	(32,813,896)	(29,110,635)
Savings and interest-checking deposits	(52,346,207)	(49,566,644)
Time deposits	(10,222,585)	(13,135,042)
Deposits at Cayman Islands office	(201,927)	(170,170)
Short-term borrowings	(163,442)	(2,132,182)
Long-term borrowings	(9,473,844)	(10,639,556)
Accrued interest payable	(75,172)	(85,145)
Trading account liabilities	(174,376)	(160,745)
Other financial instruments:
Commitments to originate real estate loans for sale	7,325	9,879
Commitments to sell real estate loans	36,653	875
Other credit-related commitments	(136,295)	(122,334)
Interest rate swap agreements used for interest rate risk management	11,892	43,892
Estimate Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets:
Cash and cash equivalents	1,249,654	1,276,678
Trading account assets	46,135	56,763
Investment securities	301,711	65,178
Estimate Fair Value [Member] | Significant Observable Inputs (Level 2) [Member]
Financial assets:
Cash and cash equivalents	70,895	91,362
Interest-bearing deposits at banks	5,000,638	7,594,350
Trading account assets	277,732	217,020
Investment securities	15,821,176	15,406,404
Loans and leases:
Commercial real estate loans	642,590	38,774
Residential real estate loans	4,912,488	4,727,816
Loans and leases, net	5,555,078	4,766,590
Accrued interest receivable	308,805	306,496
Financial liabilities:
Noninterest-bearing deposits	(32,813,896)	(29,110,635)
Savings and interest-checking deposits	(52,346,207)	(49,566,644)
Time deposits	(10,222,585)	(13,135,042)
Deposits at Cayman Islands office	(201,927)	(170,170)
Short-term borrowings	(163,442)	(2,132,182)
Long-term borrowings	(9,473,844)	(10,639,556)
Accrued interest payable	(75,172)	(85,145)
Trading account liabilities	(174,376)	(160,745)
Other financial instruments:
Commitments to sell real estate loans	36,653	875
Interest rate swap agreements used for interest rate risk management	11,892	43,892
Estimate Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member]
Financial assets:
Investment securities	121,525	189,295
Loans and leases:
Commercial loans and leases	22,239,428	20,146,201
Commercial real estate loans	32,486,838	29,005,470
Residential real estate loans	17,725,679	21,539,955
Consumer loans	12,061,590	11,550,270
Loans and leases, net	84,513,535	82,241,896
Other financial instruments:
Commitments to originate real estate loans for sale	7,325	9,879
Other credit-related commitments	$ (136,295)	$ (122,334)

Commitments and Contingencies -

Commitments and Contingencies - Company's Significant Commitments (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Commitments to extend credit
Home equity lines of credit	$ 5,499,609	$ 5,631,680
Commercial real estate loans to be sold	70,100	57,597
Other commercial real estate	6,451,709	5,949,933
Residential real estate loans to be sold	478,950	488,621
Other residential real estate	232,721	212,619
Commercial and other	12,298,473	11,802,850
Standby letters of credit	2,987,091	3,330,013
Commercial letters of credit	44,723	55,559
Financial guarantees and indemnification contracts	3,043,580	2,794,322
Commitments to sell real estate loans	$ 1,489,237	$ 782,885

Commitments and Contingencie142

Commitments and Contingencies - Additional Information (Detail) - USD ($)	May 12, 2016	Dec. 31, 2016	Dec. 31, 2015
Loss Contingencies [Line Items]
Maximum credit risk for recourse associated with loans sold under Federal National Mortgage Association Delegated Underwriting and Servicing program		$ 2,800,000,000	$ 2,500,000,000
Period of noncancelable operating lease in years		22 years
Payment of litigation settlement expense	$ 64,000,000
Minimum [Member]
Loss Contingencies [Line Items]
Range of reasonably possible losses		$ 0
Maximum [Member]
Loss Contingencies [Line Items]
Range of reasonably possible losses		$ 40,000,000

Commitments and Contingencie143

Commitments and Contingencies - Minimum Lease Payments Under Noncancellable Operating Leases (Detail) $ in Thousands	Dec. 31, 2016USD ($)
Commitments And Contingencies Disclosure [Abstract]
2,017	$ 99,847
2,018	94,448
2,019	74,814
2,020	58,216
2,021	44,508
Later years	94,825
Total	$ 466,658

Segment Information - Additiona

Segment Information - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Percent of maximum revenue from single customer on total revenues	10.00%
Hudson City [Member] | Discretionary Portfolio [Member]
Segment Reporting Information [Line Items]
Increase (decrease) in net interest income		$ 12
Increase (decrease) in income tax expense		5
Increase (decrease) in net income		7
Hudson City [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Increase (decrease) in net interest income		(12)
Increase (decrease) in income tax expense		(5)
Increase (decrease) in net income		$ (7)

Segment Information - Informati

Segment Information - Information about Company's Segments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Net interest income	$ 3,469,887	$ 2,842,587	$ 2,676,446
Noninterest income	1,825,996	1,825,037	1,779,273
Total income	5,295,883	4,667,624	4,455,719
Provision for credit losses	190,000	170,000	124,000
Amortization of core deposit and other intangible assets	42,613	26,424	33,824
Depreciation and other amortization	157,978	148,925	164,906
Other noninterest expense	2,846,894	2,647,583	2,490,744
Income before taxes	2,058,398	1,674,692	1,642,245
Income tax expense (benefit)	743,284	595,025	575,999
Net income	1,315,114	1,079,667	1,066,246
Average total assets	124,340,000	101,780,000	92,143,000
Capital expenditures	108,000	82,000	73,000
All Other [Member]
Segment Reporting Information [Line Items]
Net interest income	230,589	93,600	(21,543)
Noninterest income	570,475	594,586	599,870
Total income	801,064	688,186	578,327
Provision for credit losses	(3,910)	62,074	(12,954)
Amortization of core deposit and other intangible assets	42,613	26,424	33,824
Depreciation and other amortization	68,541	64,852	61,848
Other noninterest expense	892,625	959,345	854,883
Income before taxes	(198,805)	(424,509)	(359,274)
Income tax expense (benefit)	(140,657)	(218,379)	(201,119)
Net income	(58,148)	(206,130)	(158,155)
Average total assets	16,885,000	12,870,000	12,277,000
Capital expenditures	62,000	68,000	57,000
Business Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income	354,333	338,855	345,773
Noninterest income	108,783	108,195	105,149
Total income	463,116	447,050	450,922
Provision for credit losses	12,709	15,513	18,883
Depreciation and other amortization	404	407	405
Other noninterest expense	292,124	264,163	263,734
Income before taxes	157,879	166,967	167,900
Income tax expense (benefit)	64,533	68,209	68,630
Net income	93,346	98,758	99,270
Average total assets	5,456,000	5,339,000	5,278,000
Capital expenditures			2,000
Commercial Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income	785,874	753,604	746,344
Noninterest income	274,923	290,142	254,295
Total income	1,060,797	1,043,746	1,000,639
Provision for credit losses	34,903	25,089	33,213
Depreciation and other amortization	520	566	588
Other noninterest expense	327,616	288,303	284,091
Income before taxes	697,758	729,788	682,747
Income tax expense (benefit)	286,062	298,758	279,819
Net income	411,696	431,030	402,928
Average total assets	25,592,000	24,143,000	22,860,000
Commercial Real Estate [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income	608,385	577,922	555,358
Noninterest income	179,706	142,948	125,087
Total income	788,091	720,870	680,445
Provision for credit losses	(3,447)	(8,003)	(7,339)
Depreciation and other amortization	20,120	19,247	16,300
Other noninterest expense	204,965	169,688	169,039
Income before taxes	566,453	539,938	502,445
Income tax expense (benefit)	216,095	199,297	186,485
Net income	350,358	340,641	315,960
Average total assets	21,131,000	18,827,000	17,405,000
Discretionary Portfolio [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income	345,926	97,626	74,204
Noninterest income	26,075	28,114	27,464
Total income	372,001	125,740	101,668
Provision for credit losses	32,925	7,599	16,547
Depreciation and other amortization	472	679	891
Other noninterest expense	95,300	49,839	33,522
Income before taxes	243,304	67,623	50,708
Income tax expense (benefit)	79,766	8,351	2,365
Net income	163,538	59,272	48,343
Average total assets	40,867,000	26,648,000	20,798,000
Residential Mortgage Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income	70,655	63,939	67,482
Noninterest income	342,858	336,099	331,366
Total income	413,513	400,038	398,848
Provision for credit losses	(3,617)	(5,225)	(1,508)
Depreciation and other amortization	30,264	27,883	47,086
Other noninterest expense	258,141	233,651	216,556
Income before taxes	128,725	143,729	136,714
Income tax expense (benefit)	49,047	55,151	52,172
Net income	79,678	88,578	84,542
Average total assets	2,569,000	2,918,000	3,076,000
Retail Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income	1,074,125	917,041	908,828
Noninterest income	323,176	324,953	336,042
Total income	1,397,301	1,241,994	1,244,870
Provision for credit losses	120,437	72,953	77,158
Depreciation and other amortization	37,657	35,291	37,788
Other noninterest expense	776,123	682,594	668,919
Income before taxes	463,084	451,156	461,005
Income tax expense (benefit)	188,438	183,638	187,647
Net income	274,646	267,518	273,358
Average total assets	11,840,000	11,035,000	10,449,000
Capital expenditures	$ 46,000	$ 14,000	$ 14,000

Segment Information - Inform146

Segment Information - Information about Company's Segments (Parenthetical) (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting [Abstract]
Taxable-equivalent adjustment	$ 26,962,000	$ 24,463,000	$ 23,642,000

Segment Information - Intersegm

Segment Information - Intersegment Activity Eliminated in Arriving at Consolidated Totals was Included in "All Other" Category (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Revenues	$ 5,295,883	$ 4,667,624	$ 4,455,719
Income taxes (benefit)	743,284	595,025	575,999
Net income (loss)	1,315,114	1,079,667	1,066,246
Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Revenues	(48,625)	(48,972)	(49,800)
Expenses	(40,422)	(13,332)	(12,014)
Income taxes (benefit)	(3,338)	(14,503)	(15,375)
Net income (loss)	$ (4,865)	$ (21,137)	$ (22,411)

Regulatory Matters - Additional

Regulatory Matters - Additional Information (Detail) - USD ($)	Jan. 01, 2019	Dec. 31, 2016	Dec. 31, 2015
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Funds available for payment of dividends to M&T from banking subsidiaries		$ 627,000,000
Required subsidiary noninterest-earning reserves against certain deposit liabilities		$ 594,831,000	$ 664,586,000
Capital conservation buffer		0.625%
Scenario Forecast [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital conservation buffer	2.50%
Minimum [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Consolidated assets required per Federal Reserve Board to submit annual capital plans		$ 50,000,000,000

Regulatory Matters - Summary of

Regulatory Matters - Summary of Required Minimum and Well Capitalized Capital Ratios (Detail)	Dec. 31, 2016
Banking And Thrift [Abstract]
Common equity Tier 1 ("CET1") to risk-weighted assets, Minimum	4.50%
Tier 1 capital to risk-weighted assets, Minimum	6.00%
Total capital to risk-weighted assets, Minimum	8.00%
Leverage — Tier 1 capital to average total assets, as defined, Minimum	4.00%
Common equity Tier 1 ("CET1") to risk-weighted assets, Well Capitalized	6.50%
Tier 1 capital to risk-weighted assets, Well capitalized	8.00%
Total capital to risk-weighted assets, Well capitalized	10.00%
Leverage — Tier 1 capital to average total assets, as defined, Well capitalized	5.00%

Regulatory Matters - Capital Ra

Regulatory Matters - Capital Ratios and Amounts of Company and its Banking Subsidiaries (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Ratio	4.50%
Ratio	6.00%
Ratio	8.00%
M&T (Consolidated) [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Amount	$ 10,849,642	$ 10,485,426
Ratio	10.70%	11.08%
Minimum required amount	$ 5,195,288	$ 4,259,977
Amount	$ 12,083,948	$ 12,008,232
Ratio	11.92%	12.68%
Minimum required amount	$ 6,715,859	$ 5,679,969
Amount	$ 14,282,492	$ 14,128,454
Ratio	14.09%	14.92%
Minimum required amount	$ 8,743,289	$ 7,573,292
Amount	$ 12,083,948	$ 12,008,232
Ratio	9.99%	10.89%
Minimum required amount	$ 4,836,901	$ 4,408,971
M&T Bank [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Amount	$ 10,115,688	$ 10,680,827
Ratio	10.02%	11.33%
Minimum required amount	$ 5,175,310	$ 4,242,817
Amount	$ 10,115,688	$ 10,680,827
Ratio	10.02%	11.33%
Minimum required amount	$ 6,690,035	$ 5,657,089
Amount	$ 11,812,114	$ 12,589,917
Ratio	11.70%	13.35%
Minimum required amount	$ 8,709,668	$ 7,542,786
Amount	$ 10,115,688	$ 10,680,827
Ratio	8.41%	9.75%
Minimum required amount	$ 4,812,685	$ 4,381,617
Wilmington Trust, N.A. [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Amount	$ 496,801	$ 476,106
Ratio	57.08%	86.87%
Minimum required amount	$ 44,607	$ 24,664
Amount	$ 496,801	$ 476,106
Ratio	57.08%	86.87%
Minimum required amount	$ 57,662	$ 32,886
Amount	$ 501,111	$ 480,415
Ratio	57.57%	87.65%
Minimum required amount	$ 75,070	$ 43,848
Amount	$ 496,801	$ 476,106
Ratio	15.31%	22.38%
Minimum required amount	$ 129,774	$ 85,082

Relationship with Bayview Le151

Relationship with Bayview Lending Group LLC and Bayview Financial Holdings, L.P. - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Bayview Lending Group [Member]
Schedule of Equity Method Investments [Line Items]
Minority interest in Bayview Lending Group LLC	20.00%
Carrying value of minority interest investment in Bayview Lending Group LLC	$ 12
Bayview Lending Group and Bayview Financial [Member]
Schedule of Equity Method Investments [Line Items]
Outstanding principal balances of mortgage servicing rights	3,500	$ 4,100
Revenues from servicing	19	23	$ 26
Bayview Financial [Member]
Schedule of Equity Method Investments [Line Items]
Outstanding principal balances of residential mortgage loans from Bayview Financial	30,400	37,700
Revenues from sub-servicing	98	115	$ 115
Investment securities in held-to-maturity portfolio securitized by Bayview Financial	$ 158	$ 181

Parent Company Financial Sta152

Parent Company Financial Statements - Condensed Balance Sheet (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Investments in consolidated subsidiaries
Total assets	$ 123,449,206	$ 122,787,884
Liabilities
Long-term borrowings	9,493,835	10,653,858
Total liabilities	106,962,584	106,614,595
Shareholders’ equity	16,486,622	16,173,289	$ 12,335,896	$ 11,305,532
Total liabilities and shareholders’ equity	123,449,206	122,787,884
Parent Company [Member]
Assets
Cash in subsidiary bank	15,003	19,874
Due from consolidated bank subsidiaries
Money-market savings	1,767,184	865,274
Current income tax receivable	3,061	572
Other		10
Total due from consolidated bank subsidiaries	1,770,245	865,856
Investments in consolidated subsidiaries
Banks	15,003,964	15,581,931
Other	161,201	149,178
Investments in unconsolidated subsidiaries (note 19)	23,643	23,824
Investment in Bayview Lending Group LLC	11,908	30,264
Other assets	71,687	73,147
Total assets	17,057,651	16,744,074
Liabilities
Accrued expenses and other liabilities	54,487	56,796
Long-term borrowings	516,542	513,989
Total liabilities	571,029	570,785
Shareholders’ equity	16,486,622	16,173,289
Total liabilities and shareholders’ equity	$ 17,057,651	$ 16,744,074

Parent Company Financial Sta153

Parent Company Financial Statements - Condensed Statement of Income (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Expense
Interest on long-term borrowings	$ 231,017	$ 252,766	$ 217,247
Other expense	3,047,485	2,822,932	2,689,474
Income tax credits	(743,284)	(595,025)	(575,999)
Equity in undistributed income of subsidiaries
Net income	$ 1,315,114	$ 1,079,667	$ 1,066,246
Net income per common share
Basic	$ 7.80	$ 7.22	$ 7.47
Diluted	$ 7.78	$ 7.18	$ 7.42
Parent Company [Member]
Income
Dividends from consolidated bank subsidiaries	$ 1,930,000	$ 480,000	$ 480,000
Equity in earnings of Bayview Lending Group LLC	(10,752)	(14,267)	(16,672)
Other income	5,530	2,364	7,755
Total income	1,924,778	468,097	471,083
Expense
Interest on long-term borrowings	18,963	24,453	47,700
Other expense	21,361	16,793	15,107
Total expense	40,324	41,246	62,807
Income before income taxes and equity in undistributed income of subsidiaries	1,884,454	426,851	408,276
Income tax credits	17,247	19,965	27,284
Income before equity in undistributed income of subsidiaries	1,901,701	446,816	435,560
Equity in undistributed income of subsidiaries
Net income of subsidiaries	1,343,413	1,112,851	1,110,686
Less: dividends received	(1,930,000)	(480,000)	(480,000)
Equity in undistributed income of subsidiaries	(586,587)	632,851	630,686
Net income	$ 1,315,114	$ 1,079,667	$ 1,066,246
Net income per common share
Basic	$ 7.80	$ 7.22	$ 7.47
Diluted	$ 7.78	$ 7.18	$ 7.42

Parent Company Financial Sta154

Parent Company Financial Statements - Condensed Statement of Cash Flows (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities
Net income	$ 1,315,114	$ 1,079,667	$ 1,066,246
Adjustments to reconcile net income to net cash provided by operating activities
Provision for deferred income taxes	174,013	396,596	92,848
Net gain on sales of assets	(63,222)	(67,759)	(6,859)
Net cash provided by operating activities	1,183,411	1,742,408	1,099,041
Cash flows from investing activities
Other, net	277,961	10,876	19,531
Net cash provided by investing activities	(720,768)	7,714,282	(11,710,371)
Cash flows from financing activities
Payments on long-term borrowings	(1,119,898)	(8,912,474)	(426,275)
Purchases of treasury stock	(641,334)
Dividends paid — common	(441,891)	(375,017)	(371,199)
Dividends paid — preferred	(81,270)	(81,270)	(70,234)
Redemption of Series D preferred stock	(500,000)
Proceeds from issuance of preferred stock	495,000		346,500
Other, net	161,691	69,766	88,565
Net cash provided (used) by financing activities	(510,134)	(9,462,007)	10,311,753
Net increase (decrease) in cash and cash equivalents	(47,491)	(5,317)	(299,577)
Cash and cash equivalents at beginning of year	1,368,040	1,373,357	1,672,934
Cash and cash equivalents at end of year	1,320,549	1,368,040	1,373,357
Supplemental disclosure of cash flow information
Interest received during the year	3,903,374	3,134,311	2,893,153
Interest paid during the year	498,951	400,329	257,553
Income taxes received during the year	276,866	378,660	411,912
Parent Company [Member]
Cash flows from operating activities
Net income	1,315,114	1,079,667	1,066,246
Adjustments to reconcile net income to net cash provided by operating activities
Equity in undistributed income of subsidiaries	586,587	(632,851)	(630,686)
Provision for deferred income taxes	(3,157)	(3,655)	(6,522)
Net change in accrued income and expense	12,898	21,780	23,419
Net gain on sales of assets	(2,342)	119
Net cash provided by operating activities	1,909,100	465,060	452,457
Cash flows from investing activities
Proceeds from sales or maturities of investment securities	51	755
Other, net	13,619	14,038	10,721
Net cash provided by investing activities	13,670	14,793	10,721
Cash flows from financing activities
Payments on long-term borrowings		(322,621)	(350,010)
Purchases of treasury stock	(641,334)
Dividends paid — common	(441,891)	(375,017)	(371,199)
Dividends paid — preferred	(81,270)	(81,270)	(70,234)
Redemption of Series D preferred stock	(500,000)
Proceeds from issuance of preferred stock	495,000		346,500
Other, net	143,764	76,364	110,601
Net cash provided (used) by financing activities	(1,025,731)	(702,544)	(334,342)
Net increase (decrease) in cash and cash equivalents	897,039	(222,691)	128,836
Cash and cash equivalents at beginning of year	885,148	1,107,839	979,003
Cash and cash equivalents at end of year	1,782,187	885,148	1,107,839
Supplemental disclosure of cash flow information
Interest received during the year	1,931	1,905	2,094
Interest paid during the year	15,918	30,420	47,003
Income taxes received during the year	$ 8,877	$ 16,696	$ 24,588

Recent Accounting Developments

Recent Accounting Developments - Additional Information (Detail) $ in Thousands	Dec. 31, 2016USD ($)
Accounting Changes And Error Corrections [Abstract]
Minimum lease payments under non cancelable operating lease	$ 466,658