M&T Bank (MTB) 10-Q 5 May 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2017	Apr. 28, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1
Trading Symbol	MTB
Entity Registrant Name	M&T BANK CORP
Entity Central Index Key	36,270
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		153,863,872

Consolidated Balance Sheet (Una

Consolidated Balance Sheet (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Assets
Cash and due from banks	$ 1,286,962	$ 1,320,549
Interest-bearing deposits at banks	6,945,149	5,000,638
Trading account	174,854	323,867
Investment securities (includes pledged securities that can be sold or repledged of $519,063 at March 31, 2017; $1,203,473 at December 31, 2016)
Available for sale (cost: $12,640,244 at March 31, 2017; $13,338,301 at December 31, 2016)	12,631,000	13,332,072
Held to maturity (fair value: $2,865,885 at March 31, 2017; $2,451,222 at December 31, 2016)	2,876,119	2,457,278
Other (fair value: $461,296 at March 31, 2017; $461,118 at December 31, 2016)	461,296	461,118
Total investment securities	15,968,415	16,250,468
Loans and leases	89,555,547	91,101,677
Unearned discount	(242,545)	(248,261)
Loans and leases, net of unearned discount	89,313,002	90,853,416
Allowance for credit losses	(1,001,430)	(988,997)
Loans and leases, net	88,311,572	89,864,419
Premises and equipment	672,769	675,263
Goodwill	4,593,112	4,593,112
Core deposit and other intangible assets	94,535	97,655
Accrued interest and other assets	5,175,883	5,323,235
Total assets	123,223,251	123,449,206
Liabilities
Noninterest-bearing deposits	34,279,591	32,813,896
Savings and interest-checking deposits	53,542,149	52,346,207
Time deposits	9,028,018	10,131,846
Deposits at Cayman Islands office	192,763	201,927
Total deposits	97,042,521	95,493,876
Federal funds purchased and agreements to repurchase securities	185,102	163,442
Accrued interest and other liabilities	1,694,905	1,811,431
Long-term borrowings	8,087,619	9,493,835
Total liabilities	107,010,147	106,962,584
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 March 31, 2017 and December 31, 2016; Liquidation preference of $10,000 per share: 50,000 shares at March 31, 2017 and December 31, 2016	1,231,500	1,231,500
Common stock, $.50 par, 250,000,000 shares authorized, 159,825,445 shares issued at March 31, 2017; 159,945,678 shares issued at December 31, 2016	79,913	79,973
Common stock issuable, 28,740 shares at March 31, 2017; 32,403 shares at December 31, 2016	1,921	2,145
Additional paid-in capital	6,603,355	6,676,948
Retained earnings	9,437,450	9,222,488
Accumulated other comprehensive income (loss), net	(291,567)	(294,636)
Treasury stock - common, at cost - 6,073,095 shares at March 31, 2017; 3,764,742 shares at December 31, 2016	(849,468)	(431,796)
Total shareholders’ equity	16,213,104	16,486,622
Total liabilities and shareholders’ equity	$ 123,223,251	$ 123,449,206

Consolidated Balance Sheet (Un3

Consolidated Balance Sheet (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Pledged securities that can be sold or repledged	$ 519,063	$ 1,203,473
Investment securities, available for sale, amortized cost	12,640,244	13,338,301
Investment securities, held to maturity, fair value	2,865,885	2,451,222
Other, fair value	$ 461,296	$ 461,118
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	159,825,445	159,945,678
Common stock issuable, shares	28,740	32,403
Treasury stock, shares	6,073,095	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 (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Interest income
Loans and leases, including fees	$ 898,038	$ 863,385
Investment securities
Fully taxable	95,124	98,015
Exempt from federal taxes	430	795
Deposits at banks	12,162	10,337
Other	279	302
Total interest income	1,006,033	972,834
Interest expense
Savings and interest-checking deposits	25,634	16,305
Time deposits	18,998	24,322
Deposits at Cayman Islands office	265	193
Short-term borrowings	216	2,162
Long-term borrowings	46,660	57,888
Total interest expense	91,773	100,870
Net interest income	914,260	871,964
Provision for credit losses	55,000	49,000
Net interest income after provision for credit losses	859,260	822,964
Other income
Mortgage banking revenues	84,692	82,063
Service charges on deposit accounts	104,176	102,405
Trust income	120,015	111,077
Brokerage services income	17,384	16,004
Trading account and foreign exchange gains	9,691	7,458
Gain on bank investment securities		4
Other revenues from operations	110,887	101,922
Total other income	446,845	420,933
Other expense
Salaries and employee benefits	449,862	431,785
Equipment and net occupancy	74,366	74,178
Outside data processing and software	44,301	43,015
FDIC assessments	28,827	25,225
Advertising and marketing	16,110	21,454
Printing, postage and supplies	9,708	11,986
Amortization of core deposit and other intangible assets	8,420	12,319
Other costs of operations	156,258	156,133
Total other expense	787,852	776,095
Income before taxes	518,253	467,802
Income taxes	169,326	169,274
Net income	348,927	298,528
Net income available to common shareholders
Basic	328,562	275,744
Diluted	$ 328,567	$ 275,748
Net income per common share
Basic	$ 2.13	$ 1.74
Diluted	2.12	1.73
Cash dividends per common share	$ 0.75	$ 0.70
Average common shares outstanding
Basic	154,427	158,734
Diluted	154,949	159,181

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement Of Partners Capital [Abstract]
Net income	$ 348,927	$ 298,528
Other comprehensive income, net of tax and reclassification adjustments:
Net unrealized gains (losses) on investment securities	(1,356)	97,194
Cash flow hedges adjustments	(23)	(24)
Foreign currency translation adjustment	476	(53)
Defined benefit plans liability adjustments	3,972	4,321
Total other comprehensive income	3,069	101,438
Total comprehensive income	$ 351,996	$ 399,966

Consolidated Statement of Cash

Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities
Net income	$ 348,927	$ 298,528
Adjustments to reconcile net income to net cash provided by operating activities
Provision for credit losses	55,000	49,000
Depreciation and amortization of premises and equipment	27,429	27,141
Amortization of capitalized servicing rights	13,543	12,249
Amortization of core deposit and other intangible assets	8,420	12,319
Provision for deferred income taxes	36,731	50,075
Asset write-downs	5,118	8,940
Net gain on sales of assets	(11,647)	(5,399)
Net change in accrued interest receivable, payable	(23,782)	(16,530)
Net change in other accrued income and expense	(209)	70,766
Net change in loans originated for sale	712,954	211
Net change in trading account assets and liabilities	113,332	(59,080)
Net cash provided by operating activities	1,285,816	448,220
Cash flows from investing activities
Proceeds from sales of investment securities Available for sale		518
Proceeds from sales of investment securities Other	100	18,121
Proceeds from maturities of investment securities Available for sale	697,756	511,549
Proceeds from maturities of investment securities Held to maturity	121,455	132,636
Purchases of investment securities Available for sale	(5,143)	(311,302)
Purchases of investment securities Held to maturity	(539,516)	(5,343)
Purchases of investment securities Other	(278)	(124)
Net decrease (increase) in loans and leases	797,351	(439,712)
Net increase in interest-bearing deposits at banks	(1,944,511)	(1,950,831)
Capital expenditures, net	(21,521)	(16,307)
Net decrease in loan servicing advances	56,437	37,600
Other, net	11,863	7,920
Net cash used by investing activities	(826,007)	(2,015,275)
Cash flows from financing activities
Net increase in deposits	1,550,297	2,264,623
Net increase (decrease) in short-term borrowings	21,660	(343,838)
Payments on long-term borrowings	(1,401,410)	(317,187)
Purchases of treasury stock	(532,073)	(100,000)
Dividends paid - common	(116,566)	(112,000)
Dividends paid - preferred	(17,368)	(17,368)
Other, net	2,064	2,960
Net cash provided (used) by financing activities	(493,396)	1,377,190
Net decrease in cash and cash equivalents	(33,587)	(189,865)
Cash and cash equivalents at beginning of period	1,320,549	1,368,040
Cash and cash equivalents at end of period	1,286,962	1,178,175
Supplemental disclosure of cash flow information
Interest received during the period	1,001,129	968,223
Interest paid during the period	116,183	146,568
Income taxes paid (refunded) during the period	29,272	(86,146)
Supplemental schedule of noncash investing and financing activities
Real estate acquired in settlement of loans	23,607	33,737
Securitization of residential mortgage loans allocated to Available-for-sale investment securities	3,684	8,452
Securitization of residential mortgage loans allocated to capitalized servicing rights	$ 36	$ 92

Consolidated Statement of Chang

Consolidated Statement of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Common Stock Issuable [Member]	Additional Paid-in Capital [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, 2015	$ 16,173,289	$ 1,231,500	$ 79,782	$ 2,364	$ 6,680,768		$ 8,430,502	$ (251,627)
Total comprehensive income	399,966						298,528	101,438
Preferred stock cash dividends	(20,318)						(20,318)
Purchases of treasury stock	(100,000)								$ (100,000)
Stock-based compensation plans:
Compensation expense, net	(55)		178		(978)				745
Exercises of stock options, net	2,618		18		2,335				265
Stock purchase plan	10,594				275				10,319
Directors' stock plan	473		2		471
Deferred compensation plans, net, including dividend equivalents	29		2	(184)	234		(23)
Other	394				394
Common stock cash dividends	(111,937)						(111,937)
Ending balance at Mar. 31, 2016	16,355,053	1,231,500	79,982	2,180	6,683,499		8,596,752	(150,189)	(88,671)
Beginning 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)
Total comprehensive income	351,996						348,927	3,069
Preferred stock cash dividends	(18,237)						(18,237)
Exercise of stock warrants into common stock						$ (5,934)				$ 5,934
Purchases of treasury stock	(532,073)								(532,073)
Stock-based compensation plans:
Compensation expense, net	(11,409)		(60)		(67,016)				55,667
Exercises of stock options, net	40,662				(3,127)				43,789
Stock purchase plan	10,831				2,563				8,268
Directors' stock plan	473				126				347
Deferred compensation plans, net, including dividend equivalents	(54)			(224)	(205)		(21)		396
Common stock cash dividends	(115,707)						(115,707)
Ending balance at Mar. 31, 2017	$ 16,213,104	$ 1,231,500	$ 79,913	$ 1,921	$ 6,603,355		$ 9,437,450	$ (291,567)	$ (849,468)

Consolidated Statement of Chan8

Consolidated Statement of Changes in Shareholders' Equity (Unaudited) (Parenthetical) - $ / shares shares in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Common stock per share dividend amount	$ 0.75	$ 0.70
Retained Earnings [Member]
Common stock per share dividend amount	$ 0.75	$ 0.70
Series A Warrants [Member] | Common Stock [Member]
Exercise of warrants into shares of common stock	87,515
Exercise of warrants into shares of common stock	47,954

Significant accounting policies

Significant accounting policies	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Significant accounting policies	1. Significant accounting policies The consolidated financial statements of M&T Bank Corporation (“M&T”) and subsidiaries (“the Company”) were compiled in accordance with generally accepted accounting principles (“GAAP”) using the accounting policies set forth in note 1 of Notes to Financial Statements included in Form 10-K for the year ended December 31, 2016 (“2016 Annual Report”), except that effective January 2017 the Company adopted amended accounting guidance that is discussed in note 16 herein. The most significant of those changes related to the accounting for excess tax benefits or deficiencies associated with share-based compensation whereby beginning in 2017 those amounts are recognized in income tax expense. Previously, tax effects resulting from changes in M&T’s share price subsequent to the grant date were recorded through shareholders’ equity. The adoption of this new accounting guidance resulted in a reduction of income tax expense for the quarter ended March 31, 2017 of $18 million, or $.12 of diluted earnings per common share. In the opinion of management, all adjustments necessary for a fair presentation have been made and were all of a normal recurring nature.

Acquisitions

Acquisitions	3 Months Ended
	Mar. 31, 2017
Business Combinations [Abstract]
Acquisitions	2. Acquisitions In connection with the acquisition of Hudson City Bancorp, Inc. (“Hudson City”) on November 1, 2015 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. A summary of merger-related expenses included in the consolidated statement of income for the three-month period ended March 31, 2016 follows: (In thousands) Salaries and employee benefits $ 5,274 Equipment and net occupancy 939 Outside data processing and software 715 Advertising and marketing 4,195 Printing, postage and supplies 937 Other cost of operations 11,102 Total $ 23,162 There were no merger-related expenses during the three-month period ended March 31, 2017.

Investment securities

Investment securities	3 Months Ended
	Mar. 31, 2017
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) March 31, 2017 Investment securities available for sale: U.S. Treasury and federal agencies $ 1,907,573 181 9,504 $ 1,898,250 Obligations of states and political subdivisions 3,051 77 4 3,124 Mortgage-backed securities: Government issued or guaranteed 10,525,601 87,830 109,117 10,504,314 Privately issued 42 — 1 41 Other debt securities 133,778 1,300 15,311 119,767 Equity securities 70,199 35,873 568 105,504 12,640,244 125,261 134,505 12,631,000 Investment securities held to maturity: Obligations of states and political subdivisions 46,836 233 156 46,913 Mortgage-backed securities: Government issued or guaranteed 2,670,966 34,777 10,577 2,695,166 Privately issued 153,036 1,191 35,702 118,525 Other debt securities 5,281 — — 5,281 2,876,119 36,201 46,435 2,865,885 Other securities 461,296 — — 461,296 Total $ 15,977,659 161,462 180,940 $ 15,958,181 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 3. Investment securities, continued There were no significant gross realized gains or losses from sales of investment securities for the quarters ended March 31, 2017 and 2016. At March 31, 2017, 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 $ 156,211 156,378 Due after one year through five years 1,756,628 1,747,311 Due after five years through ten years 56,297 54,094 Due after ten years 75,266 63,358 2,044,402 2,021,141 Mortgage-backed securities available for sale 10,525,643 10,504,355 $ 12,570,045 12,525,496 Debt securities held to maturity: Due in one year or less $ 21,613 21,711 Due after one year through five years 23,326 23,261 Due after five years through ten years 1,897 1,941 Due after ten years 5,281 5,281 52,117 52,194 Mortgage-backed securities held to maturity 2,824,002 2,813,691 $ 2,876,119 2,865,885 3. Investment securities, continued A summary of investment securities that as of March 31, 2017 and December 31, 2016 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) March 31, 2017 Investment securities available for sale: U.S. Treasury and federal agencies $ 1,745,277 (9,494 ) 2,044 (10 ) Obligations of states and political subdivisions — — 472 (4 ) Mortgage-backed securities: Government issued or guaranteed 5,549,268 (108,380 ) 93,425 (737 ) Privately issued — — 25 (1 ) Other debt securities 19,052 (100 ) 75,763 (15,211 ) Equity securities 17,869 (422 ) 154 (146 ) 7,331,466 (118,396 ) 171,883 (16,109 ) Investment securities held to maturity: Obligations of states and political subdivisions 13,205 (87 ) 9,909 (69 ) Mortgage-backed securities: Government issued or guaranteed 896,556 (10,013 ) 17,472 (564 ) Privately issued 7,161 (29 ) 74,137 (35,673 ) 916,922 (10,129 ) 101,518 (36,306 ) Total $ 8,248,388 (128,525 ) 273,401 (52,415 ) 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 ) The Company owned 1,075 individual investment securities with aggregate gross unrealized losses of $181 million at March 31, 2017. Based on a review of each of the securities in the investment securities portfolio at March 31, 2017, the Company concluded that it expected to recover the amortized cost basis of its investment. As of March 31, 2017, the Company does not intend to sell nor is it anticipated that it would be required to sell any of its impaired 3. Investment securities, continued investment securities at a loss. At March 31, 2017, 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.

Loans and leases and the allowa

Loans and leases and the allowance for credit losses	3 Months Ended
	Mar. 31, 2017
Receivables [Abstract]
Loans and leases and the allowance for credit losses	4. Loans and leases and the allowance for credit losses A summary of current, past due and nonaccrual loans as of March 31, 2017 and December 31, 2016 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) March 31, 2017 Commercial, financial, leasing, etc. $ 21,986,926 38,046 6,695 387 1,825 261,497 $ 22,295,376 Real estate: Commercial 25,088,525 185,331 17,322 13,618 26,391 183,113 25,514,300 Residential builder and developer 1,714,177 15,185 — 1,972 12,798 13,573 1,757,705 Other commercial construction 5,747,834 23,973 — — 13,879 13,963 5,799,649 Residential 17,004,912 431,427 251,308 11,116 362,283 237,685 18,298,731 Residential — limited documentation 3,086,264 91,177 — — 135,759 112,560 3,425,760 Consumer: Home equity lines and loans 5,398,590 32,939 — 12,238 — 79,962 5,523,729 Automobile 3,049,712 48,751 — — — 16,109 3,114,572 Other 3,519,996 25,876 4,694 24,401 — 8,213 3,583,180 Total $ 86,596,936 892,705 280,019 63,732 552,935 926,675 $ 89,313,002 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 (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. 4. Loans and leases and the allowance for credit losses, continued One-to-four family residential mortgage loans held for sale were $297 million and $414 million at March 31, 2017 and December 31, 2016, respectively. Commercial real estate loans held for sale were $75 million at March 31, 2017 and $643 million at December 31, 2016. 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: March 31, December 31, 2017 2016 (In thousands) Outstanding principal balance $ 2,089,909 2,311,699 Carrying amount: Commercial, financial, leasing, etc. 55,671 59,928 Commercial real estate 415,047 456,820 Residential real estate 765,986 799,802 Consumer 369,803 487,721 $ 1,606,507 1,804,271 Purchased impaired loans included in the table above totaled $553 million at March 31, 2017 and $578 million at December 31, 2016, 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 three-month periods ended March 31, 2017 and 2016 follows: Three Months Ended March 31, 2017 Three Months Ended March 31, 2016 Purchased Other Purchased Other Impaired Acquired Impaired Acquired (In thousands) Balance at beginning of period $ 154,233 201,153 $ 184,618 296,434 Interest income (10,925 ) (25,518 ) (14,062 ) (37,862 ) Reclassifications from nonaccretable balance 146 3,183 629 5,664 Other (a) — 2,492 — 4,781 Balance at end of period $ 143,454 181,310 $ 171,185 269,017 (a) Other changes in expected cash flows including changes in interest rates and prepayment assumptions. 4. Loans and leases and the allowance for credit losses, continued Changes in the allowance for credit losses for the three months ended March 31, 2017 were as follows: Commercial, Financial, Real Estate Leasing, etc. Commercial Residential Consumer Unallocated Total (In thousands) Beginning balance $ 330,833 362,719 61,127 156,288 78,030 $ 988,997 Provision for credit losses 28,823 1,262 5,637 18,832 446 55,000 Net charge-offs Charge-offs (16,357 ) (5,445 ) (6,259 ) (34,503 ) — (62,564 ) Recoveries 4,461 1,474 1,507 12,555 — 19,997 Net charge-offs (11,896 ) (3,971 ) (4,752 ) (21,948 ) — (42,567 ) Ending balance $ 347,760 360,010 62,012 153,172 78,476 $ 1,001,430 Changes in the allowance for credit losses for the three months ended March 31, 2016 were as follows: Commercial, Financial, Real Estate 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 24,364 4,013 1,218 19,893 (488 ) 49,000 Net charge-offs Charge-offs (6,149 ) (1,272 ) (6,972 ) (44,319 ) — (58,712 ) Recoveries 5,247 2,413 1,887 6,925 — 16,472 Net (charge-offs) recoveries (902 ) 1,141 (5,085 ) (37,394 ) — (42,240 ) Ending balance $ 323,866 331,985 68,371 160,819 77,711 $ 962,752 4. Loans and leases and the allowance for credit losses, continued Despite the allocation in the preceding table, 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. 4. Loans and leases and the allowance for credit losses, continued The following tables provide information with respect to loans and leases that were considered impaired as of March 31, 2017 and December 31, 2016 and for the three-month periods ended March 31, 2017 and 2016. March 31, 2017 December 31, 2016 Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance Related Allowance (In thousands) With an allowance recorded: Commercial, financial, leasing, etc. $ 177,001 196,338 64,056 168,072 184,432 48,480 Real estate: Commercial 64,746 80,482 10,541 71,862 86,666 11,620 Residential builder and developer 6,870 7,031 403 7,396 8,361 506 Other commercial construction 2,203 2,673 398 2,475 2,731 448 Residential 91,077 111,477 3,738 86,680 105,944 3,457 Residential — limited documentation 81,922 97,658 5,000 82,547 97,718 6,000 Consumer: Home equity lines and loans 46,132 50,262 8,389 44,693 48,965 8,027 Automobile 16,087 16,602 3,508 16,982 18,272 3,740 Other 3,522 3,670 725 3,791 5,296 776 489,560 566,193 96,758 484,498 558,385 83,054 With no related allowance recorded: Commercial, financial, leasing, etc. 92,546 127,252 — 100,805 124,786 — Real estate: Commercial 126,437 139,103 — 113,276 121,846 — Residential builder and developer 11,748 18,863 — 14,368 21,124 — Other commercial construction 12,029 31,072 — 15,933 35,281 — Residential 14,946 22,209 — 16,823 24,161 — Residential — limited documentation 14,466 22,941 — 15,429 24,590 — 272,172 361,440 — 276,634 351,788 — Total: Commercial, financial, leasing, etc. 269,547 323,590 64,056 268,877 309,218 48,480 Real estate: Commercial 191,183 219,585 10,541 185,138 208,512 11,620 Residential builder and developer 18,618 25,894 403 21,764 29,485 506 Other commercial construction 14,232 33,745 398 18,408 38,012 448 Residential 106,023 133,686 3,738 103,503 130,105 3,457 Residential — limited documentation 96,388 120,599 5,000 97,976 122,308 6,000 Consumer: Home equity lines and loans 46,132 50,262 8,389 44,693 48,965 8,027 Automobile 16,087 16,602 3,508 16,982 18,272 3,740 Other 3,522 3,670 725 3,791 5,296 776 Total $ 761,732 927,633 96,758 761,132 910,173 83,054 4. Loans and leases and the allowance for credit losses, continued Three Months Ended March 31, 2017 Three Months Ended March 31, 2016 Interest Income Recognized Interest Income Recognized Average Recorded Investment Total Cash Basis Average Recorded Investment Total Cash Basis (In thousands) Commercial, financial, leasing, etc. $ 271,825 478 478 296,584 611 611 Real estate: Commercial 182,857 975 975 182,454 1,474 1,474 Residential builder and developer 20,051 429 429 33,750 42 42 Other commercial construction 16,328 847 847 16,868 38 38 Residential 103,875 1,636 774 96,788 1,372 882 Residential — limited documentation 97,121 1,500 384 107,473 1,472 630 Consumer: Home equity lines and loans 45,542 399 100 26,019 246 85 Automobile 16,504 275 19 21,962 339 36 Other 3,598 72 3 17,717 178 27 Total $ 757,701 6,611 4,009 799,615 5,772 3,825 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. 4. Loans and leases and the allowance for credit losses, continued 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) March 31, 2017 Pass $ 21,036,982 24,589,201 1,660,537 5,609,985 Criticized accrual 996,897 741,986 83,595 175,701 Criticized nonaccrual 261,497 183,113 13,573 13,963 Total $ 22,295,376 25,514,300 1,757,705 5,799,649 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 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 totaled $43 million and $30 million, respectively, at March 31, 2017 and $44 million and $32 million, respectively, at December 31, 2016. 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 were $18 million and $39 million, respectively, at March 31, 2017 and $16 million and $39 million, respectively, at December 31, 2016. 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. 4. Loans and leases and the allowance for credit losses, continued 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) March 31, 2017 Individually evaluated for impairment $ 64,056 11,342 8,738 12,622 $ 96,758 Collectively evaluated for impairment 283,704 346,795 49,902 140,550 820,951 Purchased impaired — 1,873 3,372 — 5,245 Allocated $ 347,760 360,010 62,012 153,172 922,954 Unallocated 78,476 Total $ 1,001,430 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 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) March 31, 2017 Individually evaluated for impairment $ 269,547 224,033 202,411 65,741 $ 761,732 Collectively evaluated for impairment 22,024,004 32,794,553 21,024,038 12,155,740 87,998,335 Purchased impaired 1,825 53,068 498,042 — 552,935 Total $ 22,295,376 33,071,654 21,724,491 12,221,481 $ 89,313,002 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 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. 4. Loans and leases and the allowance for credit losses, continued The table that follows summarizes the Company’s loan modification activities that were considered troubled debt restructurings for the three months ended March 31, 2017 and 2016: Post-modification (a) Number Pre- modification recorded investment Principal Deferral Other Combination of Concession Types Total Three Months Ended March 31, 2017 (Dollars in thousands) Commercial, financial, leasing, etc. 50 $ 11,921 $ 4,389 $ 806 $ 2,728 $ 7,923 Real estate: Commercial 20 6,702 2,991 — 3,606 6,597 Residential builder and developer 3 12,291 — — 10,879 10,879 Other commercial construction 1 102 102 — — 102 Residential 41 9,380 5,593 — 4,355 9,948 Residential — limited documentation 6 1,378 - — 1,525 1,525 Consumer: Home equity lines and loans 25 2,502 163 491 1,848 2,502 Automobile 20 390 383 — 7 390 Other 2 26 26 — — 26 Total 168 $ 44,692 $ 13,647 $ 1,297 $ 24,948 $ 39,892 Three Months Ended March 31, 2016 Commercial, financial, leasing, etc. 31 $ 17,728 $ 12,721 $ — $ 5,952 $ 18,673 Real estate: Commercial 21 7,416 3,448 — 3,924 7,372 Residential 27 4,302 2,191 — 2,369 4,560 Residential — limited documentation 6 1,437 138 — 1,379 1,517 Consumer: Home equity lines and loans 26 2,831 335 — 2,496 2,831 Automobile 72 644 521 38 85 644 Other 36 546 374 25 147 546 Total 219 $ 34,904 $ 19,728 $ 63 $ 16,352 $ 36,143 (a) Financial effects impacting the recorded investment included principal payments or advances, charge-offs and capitalized escrow arrearages. The present value of interest rate concessions, discounted at the effective rate of the original loan, was not material. 4. Loans and leases and the allowance for credit losses, continued 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 March 31, 2017 and 2016 and for which there was a subsequent payment default during the three-month periods ended March 31, 2017 and 2016, respectively, were not material. The amount of foreclosed residential real estate property held by the Company totaled $112 million and $129 million at March 31, 2017 and December 31, 2016, respectively. There were $538 million and $506 million at March 31, 2017 and December 31, 2016, respectively, in loans secured by residential real estate that were in the process of foreclosure. Of all loans in the process of foreclosure at March 31, 2017, approximately 53% were classified as purchased impaired and 20% were government guaranteed.

Borrowings

Borrowings	3 Months Ended
	Mar. 31, 2017
Debt Disclosure [Abstract]
Borrowings	5. Borrowings M&T had $517 million of fixed and variable rate junior subordinated deferrable interest debentures ("Junior Subordinated Debentures") outstanding at March 31, 2017 that are held by various trusts that 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, the securities are includable in M&T’s Tier 2 regulatory capital. 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. 5. Borrowings, continued Also included in long-term borrowings are agreements to repurchase securities of $431 million and $1.1 billion at March 31, 2017 and December 31, 2016, respectively. 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 $452 million and $1.1 billion at March 31, 2017 and December 31, 2016, respectively .

Shareholders' equity

Shareholders' equity	3 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Shareholders' equity	6. 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 as of March 31, 2017 and December 31, 2016 is presented below: 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 Series C (a) Fixed Rate Cumulative Perpetual Preferred Stock, $1,000 liquidation preference per share 151,500 $ 151,500 Series E (b) Fixed-to-Floating Rate Non-cumulative Perpetual Preferred Stock, $1,000 liquidation preference per share 350,000 $ 350,000 Series F (c) 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 $73.84 per share issued in connection with the Series A preferred stock expire in 2018 and totaled 544,279 at March 31, 2017. (b) 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. (c) 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 95,410 shares of M&T common stock at $518.81 per share was outstanding at March 31, 2017. The obligation under that warrant was assumed by M&T in an acquisition and expires in 2018.

Pension plans and other postret

Pension plans and other postretirement benefits	3 Months Ended
	Mar. 31, 2017
Compensation And Retirement Disclosure [Abstract]
Pension plans and other postretirement benefits	7. 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. Net periodic defined benefit cost for defined benefit plans consisted of the following: Pension Benefits Other Postretirement Benefits Three Months Ended March 31 2017 2016 2017 2016 (In thousands) Service cost $ 4,908 6,382 383 458 Interest cost on projected benefit obligation 19,691 20,883 1,080 1,205 Expected return on plan assets (27,200 ) (27,814 ) — — Amortization of prior service cost (credit) 125 (825 ) (350 ) (350 ) Amortization of net actuarial loss 6,800 8,300 (25 ) — Net periodic benefit cost $ 4,324 6,926 1,088 1,313 Expense incurred in connection with the Company's defined contribution pension and retirement savings plans totaled $19,419,000 and $17,690,000 for the three months ended March 31, 2017 and 2016, respectively.

Earnings per common share

Earnings per common share	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Earnings per common share	8. Earnings per common share The computations of basic earnings per common share follow: Three Months Ended March 31 2017 2016 (In thousands, except per share) Income available to common shareholders: Net income $ 348,927 298,528 Less: Preferred stock dividends (a) (18,237 ) (20,318 ) Net income available to common equity 330,690 278,210 Less: Income attributable to unvested stock-based compensation awards (2,128 ) (2,466 ) Net income available to common shareholders $ 328,562 275,744 Weighted-average shares outstanding: Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards 155,463 160,220 Less: Unvested stock-based compensation awards (1,036 ) (1,486 ) Weighted-average shares outstanding 154,427 158,734 Basic earnings per common share $ 2.13 1.74 (a) Including impact of not as yet declared cumulative dividends. 8. Earnings per common share, continued The computations of diluted earnings per common share follow: Three Months Ended March 31 2017 2016 (In thousands, except per share) Net income available to common equity $ 330,690 278,210 Less: Income attributable to unvested stock-based compensation awards (2,123 ) (2,462 ) Net income available to common shareholders $ 328,567 275,748 Adjusted weighted-average shares outstanding: Common and unvested stock-based compensation awards 155,463 160,220 Less: Unvested stock-based compensation awards (1,036 ) (1,486 ) Plus: Incremental shares from assumed conversion of stock-based compensation awards and warrants to purchase common stock 522 447 Adjusted weighted-average shares outstanding 154,949 159,181 Diluted earnings per common share $ 2.12 1.73 GAAP defines unvested share-based awards that contain nonforfeitable rights to dividends or dividend equivalents (whether paid or unpaid) as participating securities that 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 which, in accordance with GAAP, are considered participating securities. Stock-based compensation awards and warrants to purchase common stock of M&T representing 391,764 and 2,840,575 common shares during the three-month periods ended March 31, 2017 and 2016, respectively, were not included in the computations of diluted earnings per common share because the effect on those periods would have been antidilutive.

Comprehensive income

Comprehensive income	3 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Comprehensive income	9. Comprehensive income The following tables display the components of other comprehensive income (loss) and amounts reclassified from accumulated other comprehensive income (loss) to net income: Investment Securities Defined Benefit Total Amount Income With OTTI (a) All Other Plans Other Before Tax Tax Net (In thousands) Balance — January 1, 2017 $ 46,725 (73,785 ) (449,917 ) (8,268 ) $ (485,245 ) 190,609 $ (294,636 ) Other comprehensive income before reclassifications: Unrealized holding gains (losses), net (8,628 ) 5,613 — — (3,015 ) 1,182 (1,833 ) Foreign currency translation adjustment — — — 732 732 (256 ) 476 Total other comprehensive income (loss) before reclassifications (8,628 ) 5,613 — 732 (2,283 ) 926 (1,357 ) Amounts reclassified from accumulated other comprehensive income that (increase) decrease net income: Amortization of unrealized holding losses on held-to-maturity (“HTM”) securities — 787 — — 787 (b) (310 ) 477 Accretion of net gain on terminated cash flow hedges — — — (39 ) (39 ) (d) 16 (23 ) Amortization of prior service credit — — (225 ) — (225 ) (e) 88 (137 ) Amortization of actuarial losses — — 6,775 — 6,775 (e) (2,666 ) 4,109 Total reclassifications — 787 6,550 (39 ) 7,298 (2,872 ) 4,426 Total gain (loss) during the period (8,628 ) 6,400 6,550 693 5,015 (1,946 ) 3,069 Balance — March 31, 2017 $ 38,097 (67,385 ) (443,367 ) (7,575 ) (480,230 ) 188,663 $ (291,567 ) 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 (370 ) 159,660 — — 159,290 (62,680 ) 96,610 Foreign currency translation adjustment — — — (83 ) (83 ) 30 (53 ) Total other comprehensive income (loss) before reclassifications (370 ) 159,660 — (83 ) 159,207 (62,650 ) 96,557 Amounts reclassified from accumulated other comprehensive income that (increase) decrease net income: Amortization of unrealized holding losses on HTM securities — 968 — — 968 (b) (381 ) 587 Gains realized in net income — (4 ) — — (4 ) (c) 1 (3 ) Accretion of net gain on terminated cash flow hedges — — — (39 ) (39 ) (d) 15 (24 ) Amortization of prior service credit — — (1,175 ) — (1,175 ) (e) 462 (713 ) Amortization of actuarial losses — — 8,300 — 8,300 (e) (3,266 ) 5,034 Total reclassifications — 964 7,125 (39 ) 8,050 (3,169 ) 4,881 Total gain (loss) during the period (370 ) 160,624 7,125 (122 ) 167,257 (65,819 ) 101,438 Balance — March 31, 2016 $ 15,989 223,473 (482,535 ) (4,215 ) $ (247,288 ) 97,099 $ (150,189 ) (a) Other-than-temporary impairment (b) Included in interest income (c) Included in gain on bank investment securities (d) Included in interest expense (e) Included in salaries and employee benefits expense 9. Comprehensive income, continued Accumulated other comprehensive income (loss), net consisted of the following: Investment Securities Defined Benefit With OTTI All Other Plans Other Total (In thousands) Balance - December 31, 2016 $ 28,338 (44,657 ) (272,874 ) (5,443 ) $ (294,636 ) Net gain (loss) during period (5,232 ) 3,876 3,972 453 3,069 Balance — March 31, 2017 $ 23,106 (40,781 ) (268,902 ) (4,990 ) $ (291,567 )

Derivative financial instrument

Derivative financial instruments	3 Months Ended
	Mar. 31, 2017
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative financial instruments	10. 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, collateral and/or settlement provisions protecting the at-risk party. Based on adherence to the Company’s credit standards and the presence of the netting, collateral or settlement provisions, the Company believes that the credit risk inherent in these contracts was not significant as of March 31, 2017. The net effect of interest rate swap agreements was to increase net interest income by $4 million and $10 million for the three-month periods ended March 31, 2017 and 2016, respectively. 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) March 31, 2017 Fair value hedges: Fixed rate long-term borrowings (a) $ 900,000 .8 3.75 % 2.24 % $ 7,773 December 31, 2016 Fair value hedges: Fixed rate long-term borrowings (a) $ 900,000 1.1 3.75 % 2.08 % $ 11,892 (a) Under the terms of these agreements, the Company receives settlement amounts at a fixed rate and pays at a variable rate. 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 $22.3 billion and $21.6 billion at March 31, 2017 and December 31, 2016, respectively. The notional amounts of foreign currency and other option and futures contracts entered into for trading account purposes aggregated $496 million and $471 million at March 31, 2017 and December 31, 2016, respectively. 10. Derivative financial instruments, continued 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 March 31, 2017 December 31, 2016 March 31, 2017 December 31, 2016 (In thousands) Derivatives designated and qualifying as hedging instruments Fair value hedges: Interest rate swap agreements (a) $ 7,773 11,892 $ — — Commitments to sell real estate loans (a) 825 33,189 2,321 1,347 8,598 45,081 2,321 1,347 Derivatives not designated and qualifying as hedging instruments Mortgage-related commitments to originate real estate loans for sale (a) 16,847 8,060 645 735 Commitments to sell real estate loans (a) 4,126 5,210 1,582 399 Trading: Interest rate contracts (b) 109,996 228,810 134,919 167,737 Foreign exchange and other option and futures contracts (b) 4,632 7,908 3,776 6,639 135,601 249,988 140,922 175,510 Total derivatives $ 144,199 295,069 $ 143,243 176,857 (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 Three Months Ended March 31, 2017 Three Months Ended March 31, 2016 Derivative Hedged Item Derivative Hedged Item (In thousands) Derivatives in fair value hedging relationships Interest rate swap agreements: Fixed rate long-term borrowings (a) $ (4,119 ) 4,012 $ (2,633 ) 1,870 Derivatives not designated as hedging instruments Trading: Interest rate contracts (b) $ 1,950 $ 974 Foreign exchange and other option and futures contracts (b) 1,836 1,212 Total $ 3,786 $ 2,186 (a) Reported as other revenues from operations. (b) Reported as trading account and foreign exchange gains. 10. Derivative financial instruments, continued 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 $24 million and $28 million at March 31, 2017 and December 31, 2016, 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 or settlement 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 $26 million and $34 million at March 31, 2017 and December 31, 2016, respectively. After consideration of such netting arrangements, the net liability positions with counterparties aggregated $25 million and $30 million at March 31, 2017 and December 31, 2016, respectively. The Company was required to post collateral relating to those positions of $23 million and $27 million at March 31, 2017 and December 31, 2016, 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 rating were to fall below specified ratings, the counterparties of 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 March 31, 2017 was less than $1 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 March 31, 2017, the Company would not have been required to post any collateral to counterparties. The aggregate fair value of derivative financial instruments in an asset position, which are subject to enforceable master netting arrangements, was $14 million and $15 million at March 31, 2017 and December 31, 2016, respectively. After consideration of such netting arrangements, the net asset positions with counterparties aggregated $13 million and $11 million at March 31, 2017 and December 31, 2016, respectively. Counterparties posted collateral relating to those positions of $12 million and $9 million at March 31, 2017 and December 31, 2016, 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 (“variation margin”) depending on the contracts being in a net asset or liability position. The amount of initial margin posted by the Company was $83 million and $111 million at March 31, 2017 and December 31, 2016, respectively. Effective January 2017, certain clearinghouse exchanges revised their rules to re-characterize required collateral postings for variation margin as legal settlements of those positions. As a result, the fair value asset and liability amounts of derivative contracts at March 31, 2017 have been reduced by contractual settlements of $112 million and $25 million, respectively. Variation margin on derivative contracts not affected by the rule changes continue to represent collateral posted or received by the Company. For those contracts, the net fair values of derivative financial instruments cleared through clearinghouses for which variation margin is required was a net asset position of $1 million and $63 million at March 31, 2017 and December 31, 2016, respectively. Collateral posted by the clearinghouses associated with that net asset position was $1 million and $81 million at March 31, 2017 and December 31, 2016, respectively .

Variable interest entities and

Variable interest entities and asset securitizations	3 Months Ended
	Mar. 31, 2017
Text Block [Abstract]
Variable interest entities and asset securitizations	11. Variable interest entities and asset securitizations As described in note 5, 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 March 31, 2017 and December 31, 2016, 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 5. The Company has invested as a limited partner in various partnerships that collectively had total assets of approximately $1.0 billion at each of March 31, 2017 and December 31, 2016. 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 $316 million, including $114 million of unfunded commitments, at March 31, 2017 and $294 million, including $102 million of unfunded commitments, at December 31, 2016. Contingent commitments to provide additional capital contributions to these partnerships were not material at March 31, 2017. 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 amortized $13 million and $11 million of its investments in qualified affordable housing projects to income tax expense during the three-month periods ended March 31, 2017 and 2016, respectively, and recognized $16 million and $14 million of tax credits and other tax benefits during those respective periods. 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	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Fair value measurements	12. 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 March 31, 2017. 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. 12. Fair value measurements, continued 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. 12. Fair value measurements, continued The following tables present assets and liabilities at March 31, 2017 and December 31, 2016 measured at estimated fair value on a recurring basis: Fair Value Measurements Level 1 (a) Level 2 (a) Level 3 (In thousands) March 31, 2017 Trading account assets $ 174,854 46,137 128,717 — Investment securities available for sale: U.S. Treasury and federal agencies 1,898,250 — 1,898,250 — Obligations of states and political subdivisions 3,124 — 3,124 — Mortgage-backed securities: Government issued or guaranteed 10,504,314 — 10,504,314 — Privately issued 41 — — 41 Other debt securities 119,767 — 119,767 — Equity securities 105,504 63,698 41,806 — 12,631,000 63,698 12,567,261 41 Real estate loans held for sale 372,023 — 372,023 — Other assets (b) 29,571 — 12,724 16,847 Total assets $ 13,207,448 109,835 13,080,725 16,888 Trading account liabilities $ 138,695 — 138,695 — Other liabilities (b) 4,548 — 3,903 645 Total liabilities $ 143,243 — 142,598 645 December 31, 2016 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 (a) There were no significant transfers between Level 1 and Level 2 of the fair value hierarchy during the three months ended March 31, 2017 and the year ended December 31, 2016. (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). 12. Fair value measurements, continued The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the three months ended March 31, 2017 were as follows: Investment Securities Available for S Privately Issued Mortgage-Backed Securities Other Assets and Other Liabilities (In thousands) Balance — January 1, 2017 $ 44 7,325 Total gains (losses) realized/unrealized: Included in earnings — 23,940 (b) Included in other comprehensive income — — Sales — — Settlements (3 ) — Transfers in and/or out of Level 3 (a) — (15,063 ) (d) Balance — March 31, 2017 $ 41 16,202 Changes in unrealized gains included in earnings related to assets still held at March 31, 2017 $ — 15,094 (b) The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the three months ended March 31, 2016 were as follows: Investment Securities Available for Sale 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 — — 23,898 (b) Included in other comprehensive income — (2,148 ) (c) — Settlements (9 ) (205 ) — Transfers in and/or out of Level 3 (a) — — (16,892 ) (d) Balance — March 31, 2016 $ 65 45,040 16,885 Changes in unrealized gains included in earnings related to assets still held at March 31, 2016 $ — — 14,539 (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 net unrealized losses on investment securities in the consolidated statement of comprehensive income. The Company sold its collateralized debt obligations during the third and fourth quarters of 2016. (d) Transfers out of Level 3 consist of interest rate locks transferred to closed loans. 12. Fair value measurements, continued 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 March 31, 2017. 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 nonrecurring 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 $210 million at March 31, 2017 ($88 million and $122 million of which were classified as Level 2 and Level 3, respectively), $293 million at December 31, 2016 ($153 million and $140 million of which were classified as Level 2 and Level 3, respectively) and $226 million at March 31, 2016 ($127 million and $99 million of which were classified as Level 2 and Level 3, respectively). Changes in fair value recognized for partial charge-offs of loans and loan impairment reserves on loans held by the Company on March 31, 2017 and 2016 were decreases of $42 million and $27 million for the three-month periods ended March 31, 2017 and March 31, 2016, 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 $32 million and $62 million at March 31, 2017 and 2016, respectively. Changes in fair value recognized for those foreclosed assets held by the Company were not material during the three-month periods ended March 31, 2017 and 2016. 12. Fair value measurements, continued Significant unobservable inputs to Level 3 measurements The following tables present quantitative information about significant unobservable inputs used in the fair value measurements for certain Level 3 assets and liabilities at March 31, 2017 and December 31, 2016: Fair Value Valuation Technique Unobservable Inputs/Assumptions Range (Weighted- Average) (In thousands) March 31, 2017 Recurring fair value measurements Privately issued mortgage-backed securities $ 41 Two independent pricing quotes — — Net other assets (liabilities) (a) 16,202 Discounted cash flow Commitment expirations 0%-80% (24%) December 31, 2016 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%) (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. 12. Fair value measurements, continued 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: March 31, 2017 Carrying Amount Estimated Fair Value Level 1 Level 2 Level 3 (In thousands) Financial assets: Cash and cash equivalents $ 1,286,962 1,286,962 1,213,120 73,842 — Interest-bearing deposits at banks 6,945,149 6,945,149 — 6,945,149 — Trading account 174,854 174,854 46,137 128,717 — Investment securities 15,968,415 15,958,181 63,698 15,775,917 118,566 Loans and leases: Commercial loans and leases 22,295,376 21,882,456 — — 21,882,456 Commercial real estate loans 33,071,654 32,607,794 — 74,563 32,533,231 Residential real estate loans 21,724,491 21,776,908 — 4,686,339 17,090,569 Consumer loans 12,221,481 12,083,513 — — 12,083,513 Allowance for credit losses (1,001,430 ) — — — — Loans and leases, net 88,311,572 88,350,671 — 4,760,902 83,589,769 Accrued interest receivable 318,152 318,152 — 318,152 — Financial liabilities: Noninterest-bearing deposits $ (34,279,591 ) (34,279,591 ) — (34,279,591 ) — Savings and interest-checking deposits (53,542,149 ) (53,542,149 ) — (53,542,149 ) — Time deposits (9,028,018 ) (9,106,654 ) — (9,106,654 ) — Deposits at Cayman Islands office (192,763 ) (192,763 ) — (192,763 ) — Short-term borrowings (185,102 ) (185,102 ) — (185,102 ) — Long-term borrowings (8,087,619 ) (8,104,055 ) — (8,104,055 ) — Accrued interest payable (60,737 ) (60,737 ) — (60,737 ) — Trading account (138,695 ) (138,695 ) — (138,695 ) — Other financial instruments: Commitments to originate real estate loans for sale $ 16,202 16,202 — — 16,202 Commitments to sell real estate loans 1,048 1,048 — 1,048 — Other credit-related commitments (129,968 ) (129,968 ) — — (129,968 ) Interest rate swap agreements used for interest rate risk management 7,773 7,773 — 7,773 — 12. Fair value measurements, continued 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 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 (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 — 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. 12. Fair value measurements, continued 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 13, 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. 12. Fair value measurements, continued 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	3 Months Ended
	Mar. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments and contingencies	13. 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. March 31, December 31, 2017 2016 (In thousands) Commitments to extend credit Home equity lines of credit $ 5,535,221 5,499,609 Commercial real estate loans to be sold 298,039 70,100 Other commercial real estate 6,166,511 6,451,709 Residential real estate loans to be sold 473,837 478,950 Other residential real estate 240,430 232,721 Commercial and other 12,134,803 12,298,473 Standby letters of credit 2,937,504 2,987,091 Commercial letters of credit 46,560 44,723 Financial guarantees and indemnification contracts 3,477,006 3,043,580 Commitments to sell real estate loans 1,013,409 1,489,237 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 Delegated Underwriting and Servicing program. The Company's maximum credit risk for recourse associated with loans sold under this program totaled approximately $3.0 billion and $2.8 billion at March 31, 2017 and December 31, 2016, respectively. 13. Commitments and contingencies, continued 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 also has commitments under long-term operating leases. 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. At March 31, 2017 the Company believes that its obligation to loan purchasers was not material to the Company’s consolidated financial position. 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	3 Months Ended
	Mar. 31, 2017
Segment Reporting [Abstract]
Segment information	14. 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 22 of Notes to Financial Statements in the 2016 Annual Report. 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, the financial information of the reported segments is 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. As disclosed in the 2016 Annual Report, 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, financial information for the three-month period 14. Segment information, continued ended March 31, 2016 has been reclassified to conform to the current methodology. As a result, total revenues and net income increased in the Discretionary Portfolio segment and decreased in the “All Other” category by $14 million and $8 million, respectively, for the three months ended March 31, 2016 from that which was previously reported. As also described in note 22 in the 2016 Annual Report, neither goodwill nor core deposit and other intangible assets (and the amortization charges associated with such assets) resulting from acquisitions of financial institutions have been allocated to the Company's reportable segments, but are included in the “All Other” category. The Company does, however, assign such intangible assets to business units for purposes of testing for impairment. Information about the Company's segments is presented in the following table: Three Months Ended March 31 2017 2016 Total Revenues(a) Inter- segment Revenues Net Income (Loss) Total Revenues(a) Inter- segment Revenues Net Income (Loss) (In thousands) Business Banking $ 115,981 911 22,407 $ 113,689 991 25,448 Commercial Banking 273,845 920 112,750 253,617 1,056 101,327 Commercial Real Estate 195,125 407 84,547 177,380 387 80,529 Discretionary Portfolio 78,946 (12,927 ) 33,945 101,036 (14,323 ) 48,410 Residential Mortgage Banking 93,708 18,211 14,844 96,935 19,660 17,077 Retail Banking 361,237 3,047 81,873 339,046 3,014 63,288 All Other 242,263 (10,569 ) (1,439 ) 211,194 (10,785 ) (37,551 ) Total $ 1,361,105 — 348,927 $ 1,292,897 — 298,528 Average total assets Three Months Ended March 31 Year Ended December 31 2017 2016 2016 (In millions) Business Banking $ 5,596 5,424 5,456 Commercial Banking 26,723 24,838 25,592 Commercial Real Estate 22,977 19,839 21,131 Discretionary Portfolio 38,731 42,509 40,867 Residential Mortgage Banking 2,426 2,647 2,569 Retail Banking 12,204 11,568 11,840 All Other 14,321 16,427 16,885 Total $ 122,978 123,252 124,340 (a) Total revenues are comprised of net interest income and other income. Net interest income is the difference between taxable-equivalent interest earned on assets and interest paid on liabilities owed by a segment and a funding charge (credit) based on the Company's internal funds transfer and allocation 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 $7,999,000 and $6,332,000 for the three-month periods ended March 31, 2017 and 2016, respectively, and is eliminated in "All Other" total revenues. Intersegment revenues are included in total revenues of the reportable segments. The elimination of intersegment revenues is included in the determination of "All Other" total revenues.

Relationship with Bayview Lendi

Relationship with Bayview Lending Group LLC and Bayview Financial Holdings, L.P.	3 Months Ended
	Mar. 31, 2017
Text Block [Abstract]
Relationship with Bayview Lending Group LLC and Bayview Financial Holdings, L.P.	15. 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 $364 thousand at March 31, 2017. Bayview Financial Holdings, L.P. (together with its affiliates, "Bayview Financial"), a privately-held specialty mortgage finance 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 $3.4 billion and $3.5 billion at March 31, 2017 and December 31, 2016, respectively. Revenues from those servicing rights were $4 million and $5 million for the quarters ended March 31, 2017 and 2016, respectively. The Company sub-services residential mortgage loans for Bayview Financial having outstanding principal balances of $40.8 billion and $30.4 billion at March 31, 2017 and December 31, 2016, respectively. Revenues earned for sub-servicing loans for Bayview Financial were $23 million for each of the three-month periods ended March 31, 2017 and 2016. In addition, the Company held $153 million and $158 million of mortgage-backed securities in its held-to-maturity portfolio at March 31, 2017 and December 31, 2016, respectively, that were securitized by Bayview Financial. In April 2017, the Company provided a loan to Bayview Financial for $100 million at terms consistent with those offered to non-affiliated customers.

Recent accounting developments

Recent accounting developments	3 Months Ended
	Mar. 31, 2017
Accounting Changes And Error Corrections [Abstract]
Recent accounting developments	16. Recent accounting developments Effective January 1, 2017, the Company adopted amended accounting guidance for share-based transactions. The most significant aspect of the amended guidance that affects the Company requires that all excess tax benefits and tax deficiencies be recognized in income tax expense 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 adoption of this guidance resulted in an $18 million reduction of income tax expense for the quarter ended March 31, 2017 that under previous accounting guidance would have been recognized directly in shareholders’ equity. Effective January 2017, the Company also adopted 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 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 Company adopted two amendments to the accounting guidance 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. The adoption of this guidance did not have a material effect on the Company’s consolidated financial position or results of operations. 16. Recent accounting developments, continued In March 2017, the Financial Accounting Standards Board (“FASB”) issued amended guidance requiring the premium on callable debt securities held at a premium to be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. The guidance is effective for annual periods and interim periods within those annual periods beginning after December 15, 2018, with early adoption permitted. If adopted in an interim period, any adjustments should be reflected as of the beginning of the fiscal year that includes that interim period. The amendments should be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. The Company does not expect the guidance to have a material impact on its consolidated financial statements. In March 2017, the FASB issued amended guidance requiring the service cost component of the net periodic pension cost and net periodic postretirement benefit cost to be reported in the same line item or items in the income statement as other compensation costs arising from services rendered by the pertinent employees during the period (except for the amount being capitalized, if appropriate). The amendments also require disclosure of the line item(s) used in the income statement to present the components other than the service cost component if the other components are not presented in a separate line item or items in the income statement. The guidance is effective for annual periods and interim periods within those annual periods beginning after December 15, 2017, using a retrospective transition method for the presentation of the service cost and other components of net periodic pension cost and net periodic postretirement benefit cost in the income statement. The capitalization of the service cost component of net periodic pension cost and net periodic postretirement benefit cost would be applied using a prospective transition method. The amendments allow for a practical expedient that permits the use of the amounts disclosed in the Company’s pension and other postretirement benefit plan note for the prior comparative periods as the estimation basis for applying the retrospective presentation requirements. The Company is evaluating the impact the guidance may have on its consolidated financial statements. In January 2017, the 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 16. Recent accounting developments, continued 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 16. Recent accounting developments, continued 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 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. The Company was 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 16. Recent accounting developments, continued have on its consolidated financial statements. The Company 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. The amended guidance is 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 polici25

Significant accounting policies (Policies)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Basis of Accounting	The consolidated financial statements of M&T Bank Corporation (“M&T”) and subsidiaries (“the Company”) were compiled in accordance with generally accepted accounting principles (“GAAP”) using the accounting policies set forth in note 1 of Notes to Financial Statements included in Form 10-K for the year ended December 31, 2016 (“2016 Annual Report”), except that effective January 2017 the Company adopted amended accounting guidance that is discussed in note 16 herein. The most significant of those changes related to the accounting for excess tax benefits or deficiencies associated with share-based compensation whereby beginning in 2017 those amounts are recognized in income tax expense. Previously, tax effects resulting from changes in M&T’s share price subsequent to the grant date were recorded through shareholders’ equity. The adoption of this new accounting guidance resulted in a reduction of income tax expense for the quarter ended March 31, 2017 of $18 million, or $.12 of diluted earnings per common share. In the opinion of management, all adjustments necessary for a fair presentation have been made and were all of a normal recurring nature.

Acquisitions (Tables)

Acquisitions (Tables)	3 Months Ended
	Mar. 31, 2017
Business Combinations [Abstract]
Summary of Merger-Related Expenses	A summary of merger-related expenses included in the consolidated statement of income for the three-month period ended March 31, 2016 follows: (In thousands) Salaries and employee benefits $ 5,274 Equipment and net occupancy 939 Outside data processing and software 715 Advertising and marketing 4,195 Printing, postage and supplies 937 Other cost of operations 11,102 Total $ 23,162

Investment securities (Tables)

Investment securities (Tables)	3 Months Ended
	Mar. 31, 2017
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) March 31, 2017 Investment securities available for sale: U.S. Treasury and federal agencies $ 1,907,573 181 9,504 $ 1,898,250 Obligations of states and political subdivisions 3,051 77 4 3,124 Mortgage-backed securities: Government issued or guaranteed 10,525,601 87,830 109,117 10,504,314 Privately issued 42 — 1 41 Other debt securities 133,778 1,300 15,311 119,767 Equity securities 70,199 35,873 568 105,504 12,640,244 125,261 134,505 12,631,000 Investment securities held to maturity: Obligations of states and political subdivisions 46,836 233 156 46,913 Mortgage-backed securities: Government issued or guaranteed 2,670,966 34,777 10,577 2,695,166 Privately issued 153,036 1,191 35,702 118,525 Other debt securities 5,281 — — 5,281 2,876,119 36,201 46,435 2,865,885 Other securities 461,296 — — 461,296 Total $ 15,977,659 161,462 180,940 $ 15,958,181 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
Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity	At March 31, 2017, 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 $ 156,211 156,378 Due after one year through five years 1,756,628 1,747,311 Due after five years through ten years 56,297 54,094 Due after ten years 75,266 63,358 2,044,402 2,021,141 Mortgage-backed securities available for sale 10,525,643 10,504,355 $ 12,570,045 12,525,496 Debt securities held to maturity: Due in one year or less $ 21,613 21,711 Due after one year through five years 23,326 23,261 Due after five years through ten years 1,897 1,941 Due after ten years 5,281 5,281 52,117 52,194 Mortgage-backed securities held to maturity 2,824,002 2,813,691 $ 2,876,119 2,865,885 3. Investment securities, continued A summary of investment securities that as of March 31, 2017 and December 31, 2016 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:
Investment Securities in Continuous Unrealized Loss Position	Less Than 12 Months 12 Months or More Fair Value Unrealized Losses Fair Value Unrealized Losses (In thousands) March 31, 2017 Investment securities available for sale: U.S. Treasury and federal agencies $ 1,745,277 (9,494 ) 2,044 (10 ) Obligations of states and political subdivisions — — 472 (4 ) Mortgage-backed securities: Government issued or guaranteed 5,549,268 (108,380 ) 93,425 (737 ) Privately issued — — 25 (1 ) Other debt securities 19,052 (100 ) 75,763 (15,211 ) Equity securities 17,869 (422 ) 154 (146 ) 7,331,466 (118,396 ) 171,883 (16,109 ) Investment securities held to maturity: Obligations of states and political subdivisions 13,205 (87 ) 9,909 (69 ) Mortgage-backed securities: Government issued or guaranteed 896,556 (10,013 ) 17,472 (564 ) Privately issued 7,161 (29 ) 74,137 (35,673 ) 916,922 (10,129 ) 101,518 (36,306 ) Total $ 8,248,388 (128,525 ) 273,401 (52,415 ) 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 )

Loans and leases and the allo28

Loans and leases and the allowance for credit losses (Tables)	3 Months Ended
	Mar. 31, 2017
Receivables [Abstract]
Summary of Current, Past Due and Nonaccrual Loans	A summary of current, past due and nonaccrual loans as of March 31, 2017 and December 31, 2016 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) March 31, 2017 Commercial, financial, leasing, etc. $ 21,986,926 38,046 6,695 387 1,825 261,497 $ 22,295,376 Real estate: Commercial 25,088,525 185,331 17,322 13,618 26,391 183,113 25,514,300 Residential builder and developer 1,714,177 15,185 — 1,972 12,798 13,573 1,757,705 Other commercial construction 5,747,834 23,973 — — 13,879 13,963 5,799,649 Residential 17,004,912 431,427 251,308 11,116 362,283 237,685 18,298,731 Residential — limited documentation 3,086,264 91,177 — — 135,759 112,560 3,425,760 Consumer: Home equity lines and loans 5,398,590 32,939 — 12,238 — 79,962 5,523,729 Automobile 3,049,712 48,751 — — — 16,109 3,114,572 Other 3,519,996 25,876 4,694 24,401 — 8,213 3,583,180 Total $ 86,596,936 892,705 280,019 63,732 552,935 926,675 $ 89,313,002 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 (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.
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: March 31, December 31, 2017 2016 (In thousands) Outstanding principal balance $ 2,089,909 2,311,699 Carrying amount: Commercial, financial, leasing, etc. 55,671 59,928 Commercial real estate 415,047 456,820 Residential real estate 765,986 799,802 Consumer 369,803 487,721 $ 1,606,507 1,804,271
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 three-month periods ended March 31, 2017 and 2016 follows: Three Months Ended March 31, 2017 Three Months Ended March 31, 2016 Purchased Other Purchased Other Impaired Acquired Impaired Acquired (In thousands) Balance at beginning of period $ 154,233 201,153 $ 184,618 296,434 Interest income (10,925 ) (25,518 ) (14,062 ) (37,862 ) Reclassifications from nonaccretable balance 146 3,183 629 5,664 Other (a) — 2,492 — 4,781 Balance at end of period $ 143,454 181,310 $ 171,185 269,017 (a) Other changes in expected cash flows including changes in interest rates and prepayment assumptions.
Changes in Allowance for Credit Losses	Changes in the allowance for credit losses for the three months ended March 31, 2017 were as follows: Commercial, Financial, Real Estate Leasing, etc. Commercial Residential Consumer Unallocated Total (In thousands) Beginning balance $ 330,833 362,719 61,127 156,288 78,030 $ 988,997 Provision for credit losses 28,823 1,262 5,637 18,832 446 55,000 Net charge-offs Charge-offs (16,357 ) (5,445 ) (6,259 ) (34,503 ) — (62,564 ) Recoveries 4,461 1,474 1,507 12,555 — 19,997 Net charge-offs (11,896 ) (3,971 ) (4,752 ) (21,948 ) — (42,567 ) Ending balance $ 347,760 360,010 62,012 153,172 78,476 $ 1,001,430 Changes in the allowance for credit losses for the three months ended March 31, 2016 were as follows: Commercial, Financial, Real Estate 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 24,364 4,013 1,218 19,893 (488 ) 49,000 Net charge-offs Charge-offs (6,149 ) (1,272 ) (6,972 ) (44,319 ) — (58,712 ) Recoveries 5,247 2,413 1,887 6,925 — 16,472 Net (charge-offs) recoveries (902 ) 1,141 (5,085 ) (37,394 ) — (42,240 ) Ending balance $ 323,866 331,985 68,371 160,819 77,711 $ 962,752
Impaired Loans and Leases	The following tables provide information with respect to loans and leases that were considered impaired as of March 31, 2017 and December 31, 2016 and for the three-month periods ended March 31, 2017 and 2016. March 31, 2017 December 31, 2016 Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance Related Allowance (In thousands) With an allowance recorded: Commercial, financial, leasing, etc. $ 177,001 196,338 64,056 168,072 184,432 48,480 Real estate: Commercial 64,746 80,482 10,541 71,862 86,666 11,620 Residential builder and developer 6,870 7,031 403 7,396 8,361 506 Other commercial construction 2,203 2,673 398 2,475 2,731 448 Residential 91,077 111,477 3,738 86,680 105,944 3,457 Residential — limited documentation 81,922 97,658 5,000 82,547 97,718 6,000 Consumer: Home equity lines and loans 46,132 50,262 8,389 44,693 48,965 8,027 Automobile 16,087 16,602 3,508 16,982 18,272 3,740 Other 3,522 3,670 725 3,791 5,296 776 489,560 566,193 96,758 484,498 558,385 83,054 With no related allowance recorded: Commercial, financial, leasing, etc. 92,546 127,252 — 100,805 124,786 — Real estate: Commercial 126,437 139,103 — 113,276 121,846 — Residential builder and developer 11,748 18,863 — 14,368 21,124 — Other commercial construction 12,029 31,072 — 15,933 35,281 — Residential 14,946 22,209 — 16,823 24,161 — Residential — limited documentation 14,466 22,941 — 15,429 24,590 — 272,172 361,440 — 276,634 351,788 — Total: Commercial, financial, leasing, etc. 269,547 323,590 64,056 268,877 309,218 48,480 Real estate: Commercial 191,183 219,585 10,541 185,138 208,512 11,620 Residential builder and developer 18,618 25,894 403 21,764 29,485 506 Other commercial construction 14,232 33,745 398 18,408 38,012 448 Residential 106,023 133,686 3,738 103,503 130,105 3,457 Residential — limited documentation 96,388 120,599 5,000 97,976 122,308 6,000 Consumer: Home equity lines and loans 46,132 50,262 8,389 44,693 48,965 8,027 Automobile 16,087 16,602 3,508 16,982 18,272 3,740 Other 3,522 3,670 725 3,791 5,296 776 Total $ 761,732 927,633 96,758 761,132 910,173 83,054
Interest Income Recognized on Impaired Loans	Three Months Ended March 31, 2017 Three Months Ended March 31, 2016 Interest Income Recognized Interest Income Recognized Average Recorded Investment Total Cash Basis Average Recorded Investment Total Cash Basis (In thousands) Commercial, financial, leasing, etc. $ 271,825 478 478 296,584 611 611 Real estate: Commercial 182,857 975 975 182,454 1,474 1,474 Residential builder and developer 20,051 429 429 33,750 42 42 Other commercial construction 16,328 847 847 16,868 38 38 Residential 103,875 1,636 774 96,788 1,372 882 Residential — limited documentation 97,121 1,500 384 107,473 1,472 630 Consumer: Home equity lines and loans 45,542 399 100 26,019 246 85 Automobile 16,504 275 19 21,962 339 36 Other 3,598 72 3 17,717 178 27 Total $ 757,701 6,611 4,009 799,615 5,772 3,825
Summary of Loan Grades	Real Estate Commercial, Residential Other Financial, Builder and Commercial Leasing, etc. Commercial Developer Construction (In thousands) March 31, 2017 Pass $ 21,036,982 24,589,201 1,660,537 5,609,985 Criticized accrual 996,897 741,986 83,595 175,701 Criticized nonaccrual 261,497 183,113 13,573 13,963 Total $ 22,295,376 25,514,300 1,757,705 5,799,649 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
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) March 31, 2017 Individually evaluated for impairment $ 64,056 11,342 8,738 12,622 $ 96,758 Collectively evaluated for impairment 283,704 346,795 49,902 140,550 820,951 Purchased impaired — 1,873 3,372 — 5,245 Allocated $ 347,760 360,010 62,012 153,172 922,954 Unallocated 78,476 Total $ 1,001,430 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
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) March 31, 2017 Individually evaluated for impairment $ 269,547 224,033 202,411 65,741 $ 761,732 Collectively evaluated for impairment 22,024,004 32,794,553 21,024,038 12,155,740 87,998,335 Purchased impaired 1,825 53,068 498,042 — 552,935 Total $ 22,295,376 33,071,654 21,724,491 12,221,481 $ 89,313,002 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
Loan Modification Activities that were Considered Troubled Debt Restructurings	The table that follows summarizes the Company’s loan modification activities that were considered troubled debt restructurings for the three months ended March 31, 2017 and 2016: Post-modification (a) Number Pre- modification recorded investment Principal Deferral Other Combination of Concession Types Total Three Months Ended March 31, 2017 (Dollars in thousands) Commercial, financial, leasing, etc. 50 $ 11,921 $ 4,389 $ 806 $ 2,728 $ 7,923 Real estate: Commercial 20 6,702 2,991 — 3,606 6,597 Residential builder and developer 3 12,291 — — 10,879 10,879 Other commercial construction 1 102 102 — — 102 Residential 41 9,380 5,593 — 4,355 9,948 Residential — limited documentation 6 1,378 - — 1,525 1,525 Consumer: Home equity lines and loans 25 2,502 163 491 1,848 2,502 Automobile 20 390 383 — 7 390 Other 2 26 26 — — 26 Total 168 $ 44,692 $ 13,647 $ 1,297 $ 24,948 $ 39,892 Three Months Ended March 31, 2016 Commercial, financial, leasing, etc. 31 $ 17,728 $ 12,721 $ — $ 5,952 $ 18,673 Real estate: Commercial 21 7,416 3,448 — 3,924 7,372 Residential 27 4,302 2,191 — 2,369 4,560 Residential — limited documentation 6 1,437 138 — 1,379 1,517 Consumer: Home equity lines and loans 26 2,831 335 — 2,496 2,831 Automobile 72 644 521 38 85 644 Other 36 546 374 25 147 546 Total 219 $ 34,904 $ 19,728 $ 63 $ 16,352 $ 36,143 (a) Financial effects impacting the recorded investment included principal payments or advances, charge-offs and capitalized escrow arrearages. The present value of interest rate concessions, discounted at the effective rate of the original loan, was not material.

Shareholders' equity (Tables)

Shareholders' equity (Tables)	3 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Issued and Outstanding Preferred Stock	Issued and outstanding preferred stock of M&T as of March 31, 2017 and December 31, 2016 is presented below: 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 Series C (a) Fixed Rate Cumulative Perpetual Preferred Stock, $1,000 liquidation preference per share 151,500 $ 151,500 Series E (b) Fixed-to-Floating Rate Non-cumulative Perpetual Preferred Stock, $1,000 liquidation preference per share 350,000 $ 350,000 Series F (c) 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 $73.84 per share issued in connection with the Series A preferred stock expire in 2018 and totaled 544,279 at March 31, 2017. (b) 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. (c) 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.

Pension plans and other postr30

Pension plans and other postretirement benefits (Tables)	3 Months Ended
	Mar. 31, 2017
Compensation And Retirement Disclosure [Abstract]
Net Periodic Defined Benefit Cost for Defined Benefit Plans	Net periodic defined benefit cost for defined benefit plans consisted of the following: Pension Benefits Other Postretirement Benefits Three Months Ended March 31 2017 2016 2017 2016 (In thousands) Service cost $ 4,908 6,382 383 458 Interest cost on projected benefit obligation 19,691 20,883 1,080 1,205 Expected return on plan assets (27,200 ) (27,814 ) — — Amortization of prior service cost (credit) 125 (825 ) (350 ) (350 ) Amortization of net actuarial loss 6,800 8,300 (25 ) — Net periodic benefit cost $ 4,324 6,926 1,088 1,313

Earnings per common share (Tabl

Earnings per common share (Tables)	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Computations of Basic Earnings Per Common Share	The computations of basic earnings per common share follow: Three Months Ended March 31 2017 2016 (In thousands, except per share) Income available to common shareholders: Net income $ 348,927 298,528 Less: Preferred stock dividends (a) (18,237 ) (20,318 ) Net income available to common equity 330,690 278,210 Less: Income attributable to unvested stock-based compensation awards (2,128 ) (2,466 ) Net income available to common shareholders $ 328,562 275,744 Weighted-average shares outstanding: Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards 155,463 160,220 Less: Unvested stock-based compensation awards (1,036 ) (1,486 ) Weighted-average shares outstanding 154,427 158,734 Basic earnings per common share $ 2.13 1.74 (a) Including impact of not as yet declared cumulative dividends.
Computations of Diluted Earnings Per Common Share	8. Earnings per common share, continued The computations of diluted earnings per common share follow: Three Months Ended March 31 2017 2016 (In thousands, except per share) Net income available to common equity $ 330,690 278,210 Less: Income attributable to unvested stock-based compensation awards (2,123 ) (2,462 ) Net income available to common shareholders $ 328,567 275,748 Adjusted weighted-average shares outstanding: Common and unvested stock-based compensation awards 155,463 160,220 Less: Unvested stock-based compensation awards (1,036 ) (1,486 ) Plus: Incremental shares from assumed conversion of stock-based compensation awards and warrants to purchase common stock 522 447 Adjusted weighted-average shares outstanding 154,949 159,181 Diluted earnings per common share $ 2.12 1.73

Comprehensive income (Tables)

Comprehensive income (Tables)	3 Months Ended
	Mar. 31, 2017
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 comprehensive income (loss) to net income: Investment Securities Defined Benefit Total Amount Income With OTTI (a) All Other Plans Other Before Tax Tax Net (In thousands) Balance — January 1, 2017 $ 46,725 (73,785 ) (449,917 ) (8,268 ) $ (485,245 ) 190,609 $ (294,636 ) Other comprehensive income before reclassifications: Unrealized holding gains (losses), net (8,628 ) 5,613 — — (3,015 ) 1,182 (1,833 ) Foreign currency translation adjustment — — — 732 732 (256 ) 476 Total other comprehensive income (loss) before reclassifications (8,628 ) 5,613 — 732 (2,283 ) 926 (1,357 ) Amounts reclassified from accumulated other comprehensive income that (increase) decrease net income: Amortization of unrealized holding losses on held-to-maturity (“HTM”) securities — 787 — — 787 (b) (310 ) 477 Accretion of net gain on terminated cash flow hedges — — — (39 ) (39 ) (d) 16 (23 ) Amortization of prior service credit — — (225 ) — (225 ) (e) 88 (137 ) Amortization of actuarial losses — — 6,775 — 6,775 (e) (2,666 ) 4,109 Total reclassifications — 787 6,550 (39 ) 7,298 (2,872 ) 4,426 Total gain (loss) during the period (8,628 ) 6,400 6,550 693 5,015 (1,946 ) 3,069 Balance — March 31, 2017 $ 38,097 (67,385 ) (443,367 ) (7,575 ) (480,230 ) 188,663 $ (291,567 ) 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 (370 ) 159,660 — — 159,290 (62,680 ) 96,610 Foreign currency translation adjustment — — — (83 ) (83 ) 30 (53 ) Total other comprehensive income (loss) before reclassifications (370 ) 159,660 — (83 ) 159,207 (62,650 ) 96,557 Amounts reclassified from accumulated other comprehensive income that (increase) decrease net income: Amortization of unrealized holding losses on HTM securities — 968 — — 968 (b) (381 ) 587 Gains realized in net income — (4 ) — — (4 ) (c) 1 (3 ) Accretion of net gain on terminated cash flow hedges — — — (39 ) (39 ) (d) 15 (24 ) Amortization of prior service credit — — (1,175 ) — (1,175 ) (e) 462 (713 ) Amortization of actuarial losses — — 8,300 — 8,300 (e) (3,266 ) 5,034 Total reclassifications — 964 7,125 (39 ) 8,050 (3,169 ) 4,881 Total gain (loss) during the period (370 ) 160,624 7,125 (122 ) 167,257 (65,819 ) 101,438 Balance — March 31, 2016 $ 15,989 223,473 (482,535 ) (4,215 ) $ (247,288 ) 97,099 $ (150,189 ) (a) Other-than-temporary impairment (b) Included in interest income (c) Included in gain 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 OTTI All Other Plans Other Total (In thousands) Balance - December 31, 2016 $ 28,338 (44,657 ) (272,874 ) (5,443 ) $ (294,636 ) Net gain (loss) during period (5,232 ) 3,876 3,972 453 3,069 Balance — March 31, 2017 $ 23,106 (40,781 ) (268,902 ) (4,990 ) $ (291,567 )

Derivative financial instrume33

Derivative financial instruments (Tables)	3 Months Ended
	Mar. 31, 2017
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) March 31, 2017 Fair value hedges: Fixed rate long-term borrowings (a) $ 900,000 .8 3.75 % 2.24 % $ 7,773 December 31, 2016 Fair value hedges: Fixed rate long-term borrowings (a) $ 900,000 1.1 3.75 % 2.08 % $ 11,892 (a) Under the terms of these agreements, the Company receives settlement amounts at a fixed rate and pays at a variable rate.
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 March 31, 2017 December 31, 2016 March 31, 2017 December 31, 2016 (In thousands) Derivatives designated and qualifying as hedging instruments Fair value hedges: Interest rate swap agreements (a) $ 7,773 11,892 $ — — Commitments to sell real estate loans (a) 825 33,189 2,321 1,347 8,598 45,081 2,321 1,347 Derivatives not designated and qualifying as hedging instruments Mortgage-related commitments to originate real estate loans for sale (a) 16,847 8,060 645 735 Commitments to sell real estate loans (a) 4,126 5,210 1,582 399 Trading: Interest rate contracts (b) 109,996 228,810 134,919 167,737 Foreign exchange and other option and futures contracts (b) 4,632 7,908 3,776 6,639 135,601 249,988 140,922 175,510 Total derivatives $ 144,199 295,069 $ 143,243 176,857 (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 Three Months Ended March 31, 2017 Three Months Ended March 31, 2016 Derivative Hedged Item Derivative Hedged Item (In thousands) Derivatives in fair value hedging relationships Interest rate swap agreements: Fixed rate long-term borrowings (a) $ (4,119 ) 4,012 $ (2,633 ) 1,870 Derivatives not designated as hedging instruments Trading: Interest rate contracts (b) $ 1,950 $ 974 Foreign exchange and other option and futures contracts (b) 1,836 1,212 Total $ 3,786 $ 2,186 (a) Reported as other revenues from operations. (b) Reported as trading account and foreign exchange gains.

Fair value measurements (Tables

Fair value measurements (Tables)	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Estimated Fair Value on Recurring Basis	The following tables present assets and liabilities at March 31, 2017 and December 31, 2016 measured at estimated fair value on a recurring basis: Fair Value Measurements Level 1 (a) Level 2 (a) Level 3 (In thousands) March 31, 2017 Trading account assets $ 174,854 46,137 128,717 — Investment securities available for sale: U.S. Treasury and federal agencies 1,898,250 — 1,898,250 — Obligations of states and political subdivisions 3,124 — 3,124 — Mortgage-backed securities: Government issued or guaranteed 10,504,314 — 10,504,314 — Privately issued 41 — — 41 Other debt securities 119,767 — 119,767 — Equity securities 105,504 63,698 41,806 — 12,631,000 63,698 12,567,261 41 Real estate loans held for sale 372,023 — 372,023 — Other assets (b) 29,571 — 12,724 16,847 Total assets $ 13,207,448 109,835 13,080,725 16,888 Trading account liabilities $ 138,695 — 138,695 — Other liabilities (b) 4,548 — 3,903 645 Total liabilities $ 143,243 — 142,598 645 December 31, 2016 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 (a) There were no significant transfers between Level 1 and Level 2 of the fair value hierarchy during the three months ended March 31, 2017 and the year ended December 31, 2016. (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 three months ended March 31, 2017 were as follows: Investment Securities Available for S Privately Issued Mortgage-Backed Securities Other Assets and Other Liabilities (In thousands) Balance — January 1, 2017 $ 44 7,325 Total gains (losses) realized/unrealized: Included in earnings — 23,940 (b) Included in other comprehensive income — — Sales — — Settlements (3 ) — Transfers in and/or out of Level 3 (a) — (15,063 ) (d) Balance — March 31, 2017 $ 41 16,202 Changes in unrealized gains included in earnings related to assets still held at March 31, 2017 $ — 15,094 (b) The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the three months ended March 31, 2016 were as follows: Investment Securities Available for Sale 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 — — 23,898 (b) Included in other comprehensive income — (2,148 ) (c) — Settlements (9 ) (205 ) — Transfers in and/or out of Level 3 (a) — — (16,892 ) (d) Balance — March 31, 2016 $ 65 45,040 16,885 Changes in unrealized gains included in earnings related to assets still held at March 31, 2016 $ — — 14,539 (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 net unrealized losses on investment securities in the consolidated statement of comprehensive income. The Company sold its collateralized debt obligations during the third and fourth quarters of 2016. (d) 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 certain Level 3 assets and liabilities at March 31, 2017 and December 31, 2016: Fair Value Valuation Technique Unobservable Inputs/Assumptions Range (Weighted- Average) (In thousands) March 31, 2017 Recurring fair value measurements Privately issued mortgage-backed securities $ 41 Two independent pricing quotes — — Net other assets (liabilities) (a) 16,202 Discounted cash flow Commitment expirations 0%-80% (24%) December 31, 2016 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%) (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: March 31, 2017 Carrying Amount Estimated Fair Value Level 1 Level 2 Level 3 (In thousands) Financial assets: Cash and cash equivalents $ 1,286,962 1,286,962 1,213,120 73,842 — Interest-bearing deposits at banks 6,945,149 6,945,149 — 6,945,149 — Trading account 174,854 174,854 46,137 128,717 — Investment securities 15,968,415 15,958,181 63,698 15,775,917 118,566 Loans and leases: Commercial loans and leases 22,295,376 21,882,456 — — 21,882,456 Commercial real estate loans 33,071,654 32,607,794 — 74,563 32,533,231 Residential real estate loans 21,724,491 21,776,908 — 4,686,339 17,090,569 Consumer loans 12,221,481 12,083,513 — — 12,083,513 Allowance for credit losses (1,001,430 ) — — — — Loans and leases, net 88,311,572 88,350,671 — 4,760,902 83,589,769 Accrued interest receivable 318,152 318,152 — 318,152 — Financial liabilities: Noninterest-bearing deposits $ (34,279,591 ) (34,279,591 ) — (34,279,591 ) — Savings and interest-checking deposits (53,542,149 ) (53,542,149 ) — (53,542,149 ) — Time deposits (9,028,018 ) (9,106,654 ) — (9,106,654 ) — Deposits at Cayman Islands office (192,763 ) (192,763 ) — (192,763 ) — Short-term borrowings (185,102 ) (185,102 ) — (185,102 ) — Long-term borrowings (8,087,619 ) (8,104,055 ) — (8,104,055 ) — Accrued interest payable (60,737 ) (60,737 ) — (60,737 ) — Trading account (138,695 ) (138,695 ) — (138,695 ) — Other financial instruments: Commitments to originate real estate loans for sale $ 16,202 16,202 — — 16,202 Commitments to sell real estate loans 1,048 1,048 — 1,048 — Other credit-related commitments (129,968 ) (129,968 ) — — (129,968 ) Interest rate swap agreements used for interest rate risk management 7,773 7,773 — 7,773 — 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 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 (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 —

Commitments and contingencies (

Commitments and contingencies (Tables)	3 Months Ended
	Mar. 31, 2017
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. March 31, December 31, 2017 2016 (In thousands) Commitments to extend credit Home equity lines of credit $ 5,535,221 5,499,609 Commercial real estate loans to be sold 298,039 70,100 Other commercial real estate 6,166,511 6,451,709 Residential real estate loans to be sold 473,837 478,950 Other residential real estate 240,430 232,721 Commercial and other 12,134,803 12,298,473 Standby letters of credit 2,937,504 2,987,091 Commercial letters of credit 46,560 44,723 Financial guarantees and indemnification contracts 3,477,006 3,043,580 Commitments to sell real estate loans 1,013,409 1,489,237

Segment information (Tables)

Segment information (Tables)	3 Months Ended
	Mar. 31, 2017
Segment Reporting [Abstract]
Information about Company's Segments	Information about the Company's segments is presented in the following table: Three Months Ended March 31 2017 2016 Total Revenues(a) Inter- segment Revenues Net Income (Loss) Total Revenues(a) Inter- segment Revenues Net Income (Loss) (In thousands) Business Banking $ 115,981 911 22,407 $ 113,689 991 25,448 Commercial Banking 273,845 920 112,750 253,617 1,056 101,327 Commercial Real Estate 195,125 407 84,547 177,380 387 80,529 Discretionary Portfolio 78,946 (12,927 ) 33,945 101,036 (14,323 ) 48,410 Residential Mortgage Banking 93,708 18,211 14,844 96,935 19,660 17,077 Retail Banking 361,237 3,047 81,873 339,046 3,014 63,288 All Other 242,263 (10,569 ) (1,439 ) 211,194 (10,785 ) (37,551 ) Total $ 1,361,105 — 348,927 $ 1,292,897 — 298,528 Average total assets Three Months Ended March 31 Year Ended December 31 2017 2016 2016 (In millions) Business Banking $ 5,596 5,424 5,456 Commercial Banking 26,723 24,838 25,592 Commercial Real Estate 22,977 19,839 21,131 Discretionary Portfolio 38,731 42,509 40,867 Residential Mortgage Banking 2,426 2,647 2,569 Retail Banking 12,204 11,568 11,840 All Other 14,321 16,427 16,885 Total $ 122,978 123,252 124,340 (a) Total revenues are comprised of net interest income and other income. Net interest income is the difference between taxable-equivalent interest earned on assets and interest paid on liabilities owed by a segment and a funding charge (credit) based on the Company's internal funds transfer and allocation 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 $7,999,000 and $6,332,000 for the three-month periods ended March 31, 2017 and 2016, respectively, and is eliminated in "All Other" total revenues. Intersegment revenues are included in total revenues of the reportable segments. The elimination of intersegment revenues is included in the determination of "All Other" total revenues.

Significant Accounting Polici37

Significant Accounting Policies - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Significant Accounting Policies [Line Items]
Diluted	$ 2.12	$ 1.73
Adoption of New Accounting Guidance [Member]
Significant Accounting Policies [Line Items]
Reduction of Income tax expense	$ (18)
Diluted	$ 0.12

Acquisitions - Summary of Merge

Acquisitions - Summary of Merger-Related Expenses (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Summary of merger-related expenses
Salaries and employee benefits	$ 449,862,000	$ 431,785,000
Equipment and net occupancy	74,366,000	74,178,000
Outside data processing and software	44,301,000	43,015,000
Advertising and marketing	16,110,000	21,454,000
Printing, postage and supplies	9,708,000	11,986,000
Other costs of operations	156,258,000	156,133,000
Hudson City [Member]
Summary of merger-related expenses
Salaries and employee benefits		5,274,000
Equipment and net occupancy		939,000
Outside data processing and software		715,000
Advertising and marketing		4,195,000
Printing, postage and supplies		937,000
Other costs of operations		11,102,000
Total	$ 0	$ 23,162,000

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Hudson City [Member]
Business Acquisition [Line Items]
Merger-related expenses	$ 0	$ 23,162,000

Investment Securities - Amortiz

Investment Securities - Amortized Cost and Estimated Fair Value of Investment Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	$ 12,640,244	$ 13,338,301
Investment securities available for sale, gross unrealized gains	125,261	135,286
Investment securities available for sale, gross unrealized losses	134,505	141,515
Investment securities available for sale, estimated fair value	12,631,000	13,332,072
Amortized cost for held to maturity	2,876,119	2,457,278
Gross unrealized gains for held to maturity	36,201	38,662
Gross unrealized losses for held to maturity	46,435	44,718
Estimated fair value for held to maturity	2,865,885	2,451,222
Other securities, Amortized cost	461,296	461,118
Other securities, Estimated fair value	461,296	461,118
Total Amortized cost	15,977,659	16,256,697
Total for Gross unrealized gains	161,462	173,948
Total for Gross unrealized losses	180,940	186,233
Total for Estimated fair value	15,958,181	16,244,412
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	1,907,573	1,912,110
Investment securities available for sale, gross unrealized gains	181	386
Investment securities available for sale, gross unrealized losses	9,504	9,952
Investment securities available for sale, estimated fair value	1,898,250	1,902,544
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	3,051	3,570
Investment securities available for sale, gross unrealized gains	77	77
Investment securities available for sale, gross unrealized losses	4	6
Investment securities available for sale, estimated fair value	3,124	3,641
Amortized cost for held to maturity	46,836	60,858
Gross unrealized gains for held to maturity	233	267
Gross unrealized losses for held to maturity	156	224
Estimated fair value for held to maturity	46,913	60,901
Government Issued or Guaranteed [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	10,525,601	10,980,507
Investment securities available for sale, gross unrealized gains	87,830	88,343
Investment securities available for sale, gross unrealized losses	109,117	113,989
Investment securities available for sale, estimated fair value	10,504,314	10,954,861
Amortized cost for held to maturity	2,670,966	2,233,173
Gross unrealized gains for held to maturity	34,777	37,498
Gross unrealized losses for held to maturity	10,577	7,374
Estimated fair value for held to maturity	2,695,166	2,263,297
Privately Issued [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	42	45
Investment securities available for sale, gross unrealized losses	1	1
Investment securities available for sale, estimated fair value	41	44
Amortized cost for held to maturity	153,036	157,704
Gross unrealized gains for held to maturity	1,191	897
Gross unrealized losses for held to maturity	35,702	37,120
Estimated fair value for held to maturity	118,525	121,481
Other Debt Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	133,778	134,105
Investment securities available for sale, gross unrealized gains	1,300	1,407
Investment securities available for sale, gross unrealized losses	15,311	16,996
Investment securities available for sale, estimated fair value	119,767	118,516
Amortized cost for held to maturity	5,281	5,543
Estimated fair value for held to maturity	5,281	5,543
Equity Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	70,199	307,964
Investment securities available for sale, gross unrealized gains	35,873	45,073
Investment securities available for sale, gross unrealized losses	568	571
Investment securities available for sale, estimated fair value	$ 105,504	$ 352,466

Investment Securities - Additio

Investment Securities - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2017USD ($)Investment	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)
Amortized Cost And Fair Value Debt Securities [Abstract]
Gross realized gains on sale of investment securities	$ 0	$ 0
Number of investment securities with aggregate gross unrealized losses | Investment	0
Unrealized losses on individual investment securities	$ 180,940,000		$ 186,233,000
Cost method investment securities	$ 0

Investment Securities - Amort42

Investment Securities - Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Debt securities available for sale:
Due in one year or less	$ 156,211
Due after one year through five years	1,756,628
Due after five years through ten years	56,297
Due after ten years	75,266
Total available for sale (amortized cost)	2,044,402
Mortgage-backed securities available for sale	10,525,643
Total	12,570,045
Debt securities held to maturity:
Due in one year or less	21,613
Due after one year through five years	23,326
Due after five years through ten years	1,897
Due after ten years	5,281
Total available for held to maturity (amortized cost)	52,117
Mortgage-backed securities held to maturity	2,824,002
Amortized cost for held to maturity	2,876,119	$ 2,457,278
Debt securities available for sale:
Due in one year or less	156,378
Due after one year through five years	1,747,311
Due after five years through ten years	54,094
Due after ten years	63,358
Total available for sale (fair value)	2,021,141
Mortgage-backed securities available for sale	10,504,355
Total	12,525,496
Debt securities held to maturity:
Due in one year or less	21,711
Due after one year through five years	23,261
Due after five years through ten years	1,941
Due after ten years	5,281
Total available for held to maturity (fair value)	52,194
Mortgage-backed securities held to maturity	2,813,691
Total	$ 2,865,885	$ 2,451,222

Investment Securities - Investm

Investment Securities - Investment Securities in Continuous Unrealized Loss Position (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months	$ 7,331,466	$ 8,458,946
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses	(118,396)	(123,747)
Estimated fair value, 12 months or more	171,883	169,469
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(16,109)	(17,768)
Held to maturity, Estimated fair value, Less than 12 months	916,922	654,731
Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses	(10,129)	(8,190)
Held to maturity, Estimated fair value, 12 months or more	101,518	86,388
Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses	(36,306)	(36,528)
Total investment securities, fair value less than 12 months	8,248,388	9,113,677
Investment Securities Continuous Unrealized Loss Position Less Than Twelve Months Aggregate Losses	(128,525)	(131,937)
Total of investment securities, fair value, 12 Months or More	273,401	255,857
Investment Securities Continuous Unrealized Loss Position Twelve Months or Longer Aggregate Losses	(52,415)	(54,296)
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	1,745,277	1,710,241
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses	(9,494)	(9,950)
Estimated fair value, 12 months or more	2,044	2,295
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(10)	(2)
Obligations of States and Political Subdivisions [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, 12 months or more	472	593
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(4)	(6)
Held to maturity, Estimated fair value, Less than 12 months	13,205	17,988
Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses	(87)	(126)
Held to maturity, Estimated fair value, 12 months or more	9,909	11,891
Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses	(69)	(98)
Government Issued or Guaranteed [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months	5,549,268	6,730,829
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses	(108,380)	(113,374)
Estimated fair value, 12 months or more	93,425	81,003
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(737)	(615)
Held to maturity, Estimated fair value, Less than 12 months	896,556	618,832
Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses	(10,013)	(6,842)
Held to maturity, Estimated fair value, 12 months or more	17,472	17,481
Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses	(564)	(532)
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	25	27
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(1)	(1)
Other Debt Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months	19,052	100
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses	(100)	(1)
Estimated fair value, 12 months or more	75,763	85,400
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(15,211)	(16,995)
Equity Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months	17,869	17,776
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses	(422)	(422)
Estimated fair value, 12 months or more	154	151
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(146)	(149)
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	7,161	17,911
Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses	(29)	(1,222)
Held to maturity, Estimated fair value, 12 months or more	74,137	57,016
Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses	$ (35,673)	$ (35,898)

Loans and Leases and the Allo44

Loans and Leases and the Allowance for Credit Losses - Summary of Current, Past Due and Nonaccrual Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	$ 86,596,936	$ 87,968,321
30-89 Days Past Due	892,705	1,025,245
Accruing Loans Past Due 90 Days or More	280,019	300,659
Purchased Impaired	552,935	578,032
Nonaccrual	926,675	920,015
Loans and leases, net of unearned discount	89,313,002	90,853,416
Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing Loans Past Due 90 Days or More	63,732	61,144
Commercial, Financial, Leasing, etc. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	21,986,926	22,287,857
30-89 Days Past Due	38,046	53,503
Accruing Loans Past Due 90 Days or More	6,695	6,195
Purchased Impaired	1,825	641
Nonaccrual	261,497	261,434
Loans and leases, net of unearned discount	22,295,376	22,610,047
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	387	417
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	25,088,525	25,076,684
30-89 Days Past Due	185,331	183,531
Accruing Loans Past Due 90 Days or More	17,322	7,054
Purchased Impaired	26,391	31,404
Nonaccrual	183,113	176,201
Loans and leases, net of unearned discount	25,514,300	25,487,744
Commercial [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing Loans Past Due 90 Days or More	13,618	12,870
Residential Builder and Developer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,714,177	1,884,989
30-89 Days Past Due	15,185	4,667
Accruing Loans Past Due 90 Days or More		5
Purchased Impaired	12,798	14,006
Nonaccrual	13,573	16,707
Loans and leases, net of unearned discount	1,757,705	1,922,326
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	1,972	1,952
Other Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	5,747,834	5,985,118
30-89 Days Past Due	23,973	77,701
Accruing Loans Past Due 90 Days or More		922
Purchased Impaired	13,879	14,274
Nonaccrual	13,963	18,111
Loans and leases, net of unearned discount	5,799,649	6,096,324
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
Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	17,004,912	17,631,377
30-89 Days Past Due	431,427	485,468
Accruing Loans Past Due 90 Days or More	251,308	281,298
Purchased Impaired	362,283	378,549
Nonaccrual	237,685	229,242
Loans and leases, net of unearned discount	18,298,731	19,017,471
Residential [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing Loans Past Due 90 Days or More	11,116	11,537
Residential Limited Documentation [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	3,086,264	3,239,344
30-89 Days Past Due	91,177	88,366
Purchased Impaired	135,759	139,158
Nonaccrual	112,560	106,573
Loans and leases, net of unearned discount	3,425,760	3,573,441
Home Equity Lines and Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	5,398,590	5,502,091
30-89 Days Past Due	32,939	44,565
Nonaccrual	79,962	81,815
Loans and leases, net of unearned discount	5,523,729	5,641,149
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	12,238	12,678
Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	3,049,712	2,869,232
30-89 Days Past Due	48,751	56,158
Nonaccrual	16,109	18,674
Loans and leases, net of unearned discount	3,114,572	2,944,065
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
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	3,519,996	3,491,629
30-89 Days Past Due	25,876	31,286
Accruing Loans Past Due 90 Days or More	4,694	5,185
Nonaccrual	8,213	11,258
Loans and leases, net of unearned discount	3,583,180	3,560,849
Other [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing Loans Past Due 90 Days or More	$ 24,401	$ 21,491

Loans and Leases and the Allo45

Loans and Leases and the Allowance for Credit Losses - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Loans And Leases Receivable [Line Items]
Commercial real estate loans held for sale	$ 75		$ 643
Contractual principal and interest payments	$ 553		578
Loan delinquent period	90 days
Minimum delinquency period for loan level collectability analysis consumer mortgage	150 days
Amount of foreclosed residential real estate property held	$ 112		129
Loans secured by residential real estate that were in the process of foreclosure	$ 538		506
Percentage loans in the process of foreclosure, serviced by other entities, classified as purchased impaired	53.00%
Percentage loans in the process of foreclosure, serviced by other entities, classified as government guaranteed	20.00%
Residential Mortgage Loans [Member]
Loans And Leases Receivable [Line Items]
Mortgage loans held for sale	$ 297		414
Carrying value of loans for which partial charge-off has been recognized	43		44
Mortgage loans on real real estate not requiring charge off due to collateral carrying amount	18		16
Home Equity Loans and Lines of Credit [Member]
Loans And Leases Receivable [Line Items]
Carrying value of loans for which partial charge-off has been recognized	30		32
Mortgage loans on real real estate not requiring charge off due to collateral carrying amount	$ 39		$ 39
Maximum [Member]
Loans And Leases Receivable [Line Items]
Purchased impaired loans as a percentage of total assets	1.00%	1.00%

Loans and Leases and the Allo46

Loans and Leases and the Allowance for Credit Losses - Outstanding Principal Balance and Carrying Amount of Loans and Included in Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Outstanding principal and carrying value of acquired loans recorded at fair value
Outstanding principal balance	$ 2,089,909	$ 2,311,699
Carrying amount	1,606,507	1,804,271
Commercial, Financial, Leasing, etc. [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	55,671	59,928
Commercial Real Estate [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	415,047	456,820
Residential Real Estate [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	765,986	799,802
Consumer [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	$ 369,803	$ 487,721

Loans and Leases and the Allo47

Loans and Leases and the Allowance for Credit Losses - Summary of Changes in Accretable Yield for Acquired Loans (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Purchased Impaired [Member]
Summary of changes in Accretable Yield for acquired loans
Balance at beginning of period	$ 154,233	$ 184,618
Interest income	(10,925)	(14,062)
Reclassifications from nonaccretable balance	146	629
Balance at end of period	143,454	171,185
Other Acquired [Member]
Summary of changes in Accretable Yield for acquired loans
Balance at beginning of period	201,153	296,434
Interest income	(25,518)	(37,862)
Reclassifications from nonaccretable balance	3,183	5,664
Other	2,492	4,781
Balance at end of period	$ 181,310	$ 269,017

Loans and Leases and the Allo48

Loans and Leases and the Allowance for Credit Losses - Changes in Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$ 988,997	$ 955,992
Provision for credit losses	55,000	49,000
Net charge-offs
Charge-offs	(62,564)	(58,712)
Recoveries	19,997	16,472
Net (charge-offs) recoveries	(42,567)	(42,240)
Ending balance	1,001,430	962,752
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	330,833	300,404
Provision for credit losses	28,823	24,364
Net charge-offs
Charge-offs	(16,357)	(6,149)
Recoveries	4,461	5,247
Net (charge-offs) recoveries	(11,896)	(902)
Ending balance	347,760	323,866
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	362,719	326,831
Provision for credit losses	1,262	4,013
Net charge-offs
Charge-offs	(5,445)	(1,272)
Recoveries	1,474	2,413
Net (charge-offs) recoveries	(3,971)	1,141
Ending balance	360,010	331,985
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	61,127	72,238
Provision for credit losses	5,637	1,218
Net charge-offs
Charge-offs	(6,259)	(6,972)
Recoveries	1,507	1,887
Net (charge-offs) recoveries	(4,752)	(5,085)
Ending balance	62,012	68,371
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	156,288	178,320
Provision for credit losses	18,832	19,893
Net charge-offs
Charge-offs	(34,503)	(44,319)
Recoveries	12,555	6,925
Net (charge-offs) recoveries	(21,948)	(37,394)
Ending balance	153,172	160,819
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	78,030	78,199
Provision for credit losses	446	(488)
Net charge-offs
Ending balance	$ 78,476	$ 77,711

Loans and Leases and the Allo49

Loans and Leases and the Allowance for Credit Losses - Impaired Loans and Leases (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	$ 489,560	$ 484,498
Unpaid principal balance with related allowance	566,193	558,385
Related allowance	96,758	83,054
Recorded investment with no related allowance	272,172	276,634
Unpaid principal balance with no related allowance	361,440	351,788
Recorded investment	761,732	761,132
Unpaid principal balance	927,633	910,173
Commercial Real Estate [Member]
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	64,746	71,862
Unpaid principal balance with related allowance	80,482	86,666
Related allowance	10,541	11,620
Recorded investment with no related allowance	126,437	113,276
Unpaid principal balance with no related allowance	139,103	121,846
Recorded investment	191,183	185,138
Unpaid principal balance	219,585	208,512
Automobile [Member]
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	16,087	16,982
Unpaid principal balance with related allowance	16,602	18,272
Related allowance	3,508	3,740
Recorded investment	16,087	16,982
Unpaid principal balance	16,602	18,272
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	177,001	168,072
Unpaid principal balance with related allowance	196,338	184,432
Related allowance	64,056	48,480
Recorded investment with no related allowance	92,546	100,805
Unpaid principal balance with no related allowance	127,252	124,786
Recorded investment	269,547	268,877
Unpaid principal balance	323,590	309,218
Residential Builder and Developer [Member]
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	6,870	7,396
Unpaid principal balance with related allowance	7,031	8,361
Related allowance	403	506
Recorded investment with no related allowance	11,748	14,368
Unpaid principal balance with no related allowance	18,863	21,124
Recorded investment	18,618	21,764
Unpaid principal balance	25,894	29,485
Other Commercial Construction [Member]
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	2,203	2,475
Unpaid principal balance with related allowance	2,673	2,731
Related allowance	398	448
Recorded investment with no related allowance	12,029	15,933
Unpaid principal balance with no related allowance	31,072	35,281
Recorded investment	14,232	18,408
Unpaid principal balance	33,745	38,012
Residential [Member]
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	91,077	86,680
Unpaid principal balance with related allowance	111,477	105,944
Related allowance	3,738	3,457
Recorded investment with no related allowance	14,946	16,823
Unpaid principal balance with no related allowance	22,209	24,161
Recorded investment	106,023	103,503
Unpaid principal balance	133,686	130,105
Residential Limited Documentation [Member]
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	81,922	82,547
Unpaid principal balance with related allowance	97,658	97,718
Related allowance	5,000	6,000
Recorded investment with no related allowance	14,466	15,429
Unpaid principal balance with no related allowance	22,941	24,590
Recorded investment	96,388	97,976
Unpaid principal balance	120,599	122,308
Home Equity Lines and Loans [Member]
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	46,132	44,693
Unpaid principal balance with related allowance	50,262	48,965
Related allowance	8,389	8,027
Recorded investment	46,132	44,693
Unpaid principal balance	50,262	48,965
Other [Member]
Financing Receivable Impaired [Line Items]
Recorded investment with related allowance	3,522	3,791
Unpaid principal balance with related allowance	3,670	5,296
Related allowance	725	776
Recorded investment	3,522	3,791
Unpaid principal balance	$ 3,670	$ 5,296

Loans and Leases and the Allo50

Loans and Leases and the Allowance for Credit Losses - Interest Income Recognized on Impaired Loans (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	$ 757,701	$ 799,615
Interest income recognized, Total	6,611	5,772
Interest income recognized, Cash basis	4,009	3,825
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	182,857	182,454
Interest income recognized, Total	975	1,474
Interest income recognized, Cash basis	975	1,474
Commercial, Financial, Leasing, etc. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	271,825	296,584
Interest income recognized, Total	478	611
Interest income recognized, Cash basis	478	611
Residential Builder and Developer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	20,051	33,750
Interest income recognized, Total	429	42
Interest income recognized, Cash basis	429	42
Other Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	16,328	16,868
Interest income recognized, Total	847	38
Interest income recognized, Cash basis	847	38
Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	103,875	96,788
Interest income recognized, Total	1,636	1,372
Interest income recognized, Cash basis	774	882
Residential Limited Documentation [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	97,121	107,473
Interest income recognized, Total	1,500	1,472
Interest income recognized, Cash basis	384	630
Home Equity Lines and Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	45,542	26,019
Interest income recognized, Total	399	246
Interest income recognized, Cash basis	100	85
Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	16,504	21,962
Interest income recognized, Total	275	339
Interest income recognized, Cash basis	19	36
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	3,598	17,717
Interest income recognized, Total	72	178
Interest income recognized, Cash basis	$ 3	$ 27

Loans and Leases and the Allo51

Loans and Leases and the Allowance for Credit Losses - Summary of Loan Grades (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	$ 89,313,002	$ 90,853,416
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	22,295,376	22,610,047
Commercial, Financial, Leasing, etc. [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	21,036,982	21,398,581
Commercial, Financial, Leasing, etc. [Member] | Criticized Accrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	996,897	950,032
Commercial, Financial, Leasing, etc. [Member] | Criticized Nonaccrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	261,497	261,434
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	25,514,300	25,487,744
Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	24,589,201	24,570,269
Commercial [Member] | Criticized Accrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	741,986	741,274
Commercial [Member] | Criticized Nonaccrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	183,113	176,201
Residential Builder and Developer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	1,757,705	1,922,326
Residential Builder and Developer [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	1,660,537	1,789,071
Residential Builder and Developer [Member] | Criticized Accrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	83,595	116,548
Residential Builder and Developer [Member] | Criticized Nonaccrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	13,573	16,707
Other Commercial Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	5,799,649	6,096,324
Other Commercial Construction [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	5,609,985	5,912,351
Other Commercial Construction [Member] | Criticized Accrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	175,701	165,862
Other Commercial Construction [Member] | Criticized Nonaccrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	$ 13,963	$ 18,111

Loans and Leases and the Allo52

Loans and Leases and the Allowance for Credit Losses - Allocation of Allowance for Credit Losses on Basis of Company's Impairment Methodology (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	$ 96,758	$ 82,980
Allowance for credit losses	820,951	822,392
Allowance for credit losses	1,001,430	988,997	$ 962,752	$ 955,992
Purchased Impaired [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	5,245	5,595
Allocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	922,954	910,967
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	78,476	78,030	$ 77,711	$ 78,199
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	64,056	48,480
Allowance for credit losses	283,704	282,353
Commercial, Financial, Leasing, etc. [Member] | Allocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	347,760	330,833
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	11,342	12,500
Allowance for credit losses	346,795	348,301
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	1,873	1,918
Commercial Real Estate [Member] | Allocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	360,010	362,719
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	8,738	9,457
Allowance for credit losses	49,902	47,993
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	3,372	3,677
Residential Real Estate [Member] | Allocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	62,012	61,127
Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	12,622	12,543
Allowance for credit losses	140,550	143,745
Consumer Loans [Member] | Allocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	$ 153,172	$ 156,288

Loans and Leases and the Allo53

Loans and Leases and the Allowance for Credit Losses - Recorded Investment in Loans and Leases on Basis of Company's Impairment Methodology (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	$ 89,313,002	$ 90,853,416
Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	761,732	760,452
Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	87,998,335	89,514,932
Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	552,935	578,032
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	22,295,376	22,610,047
Commercial, Financial, Leasing, etc. [Member] | Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	269,547	268,877
Commercial, Financial, Leasing, etc. [Member] | Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	22,024,004	22,340,529
Commercial, Financial, Leasing, etc. [Member] | Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	1,825	641
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	33,071,654	33,506,394
Commercial Real Estate [Member] | Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	224,033	224,630
Commercial Real Estate [Member] | Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	32,794,553	33,222,080
Commercial Real Estate [Member] | Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	53,068	59,684
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	21,724,491	22,590,912
Residential Real Estate [Member] | Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	202,411	201,479
Residential Real Estate [Member] | Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	21,024,038	21,871,726
Residential Real Estate [Member] | Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	498,042	517,707
Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	12,221,481	12,146,063
Consumer Loans [Member] | Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	65,741	65,466
Consumer Loans [Member] | Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	$ 12,155,740	$ 12,080,597

Loans and Leases and the Allo54

Loans and Leases and the Allowance for Credit Losses - Loan Modification Activities that were Considered Troubled Debt Restructurings (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)Modification	Mar. 31, 2016USD ($)Modification
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	168	219
Pre-modification recorded investment	$ 44,692	$ 34,904
Post- modification	$ 39,892	$ 36,143
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	20	21
Pre-modification recorded investment	$ 6,702	$ 7,416
Post- modification	6,597	7,372
Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	13,647	19,728
Principal Deferral [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	2,991	3,448
Other [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	1,297	63
Combination of Concession Types [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	24,948	16,352
Combination of Concession Types [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	$ 3,606	$ 3,924
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	50	31
Pre-modification recorded investment	$ 11,921	$ 17,728
Post- modification	7,923	18,673
Commercial, Financial, Leasing, etc. [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	4,389	12,721
Commercial, Financial, Leasing, etc. [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	806
Commercial, Financial, Leasing, etc. [Member] | Combination of Concession Types [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	$ 2,728	$ 5,952
Residential Builder and Developer [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	3
Pre-modification recorded investment	$ 12,291
Post- modification	10,879
Residential Builder and Developer [Member] | Combination of Concession Types [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	$ 10,879
Other Commercial Construction [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	1
Pre-modification recorded investment	$ 102
Post- modification	102
Other Commercial Construction [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	$ 102
Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	41	27
Pre-modification recorded investment	$ 9,380	$ 4,302
Post- modification	9,948	4,560
Residential [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	5,593	2,191
Residential [Member] | Combination of Concession Types [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	$ 4,355	$ 2,369
Residential Limited Documentation [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	6	6
Pre-modification recorded investment	$ 1,378	$ 1,437
Post- modification	1,525	1,517
Residential Limited Documentation [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Post- modification		138
Residential Limited Documentation [Member] | Combination of Concession Types [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	$ 1,525	$ 1,379
Home Equity Lines and Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	25	26
Pre-modification recorded investment	$ 2,502	$ 2,831
Post- modification	2,502	2,831
Home Equity Lines and Loans [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	163	335
Home Equity Lines and Loans [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	491
Home Equity Lines and Loans [Member] | Combination of Concession Types [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	$ 1,848	$ 2,496
Automobile [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	20	72
Pre-modification recorded investment	$ 390	$ 644
Post- modification	390	644
Automobile [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	383	521
Automobile [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Post- modification		38
Automobile [Member] | Combination of Concession Types [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	$ 7	$ 85
Other [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	2	36
Pre-modification recorded investment	$ 26	$ 546
Post- modification	26	546
Other [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Post- modification	$ 26	374
Other [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Post- modification		25
Other [Member] | Combination of Concession Types [Member]
Financing Receivable, Modifications [Line Items]
Post- modification		$ 147

Borrowings - Additional Informa

Borrowings - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Debt Instruments [Abstract]
Junior subordinated debentures	$ 517
Trust preferred capital securities	0.00%
Debt Maturity, Start Year	Jan. 1, 2027
Debt Maturity, End Year	Dec. 31, 2033
Agreements to repurchase securities	$ 431	$ 1,100
Collateral posted	$ 452	$ 1,100

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail) - $ / shares	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
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	$ 518.81
Warrant to purchase common stock	95,410	95,410
Warrants, year of expiration	2,018

Shareholders' Equity - Issued a

Shareholders' Equity - Issued and Outstanding Preferred Stock (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
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 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	50,000
Preferred stock, Shares Outstanding	50,000	50,000
Carrying Value	$ 500,000	$ 500,000

Shareholders' Equity - Issued58

Shareholders' Equity - Issued and Outstanding Preferred Stock (Parenthetical) (Detail) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
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	$ 73.84	$ 73.84
Warrants and rights outstanding	544,279
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 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	3.61%	3.61%
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	$ 10,000
Preferred stock dividend rate	5.125%	5.125%
Date of change in the dividend rate	Oct. 31, 2026	Oct. 31, 2026
London Interbank offered rate plus basis points	3.52%	3.52%
Preferred shares redemption date	Nov. 1, 2026	Nov. 1, 2026
Preferred Stock, Redemption Feature, Redemption Term	90 days	90 days

Pension Plans and Other Postr59

Pension Plans and Other Postretirement Benefits - Net Periodic Defined Benefit Cost for Defined Benefit Plans (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4,908	$ 6,382
Interest cost on projected benefit obligation	19,691	20,883
Expected return on plan assets	(27,200)	(27,814)
Amortization of prior service cost (credit)	125	(825)
Amortization of net actuarial loss	6,800	8,300
Net periodic benefit cost	4,324	6,926
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	383	458
Interest cost on projected benefit obligation	1,080	1,205
Amortization of prior service cost (credit)	(350)	(350)
Amortization of net actuarial loss	(25)
Net periodic benefit cost	$ 1,088	$ 1,313

Pension Plans and Other Postr60

Pension Plans and Other Postretirement Benefits - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Compensation And Retirement Disclosure [Abstract]
Defined contribution pension and retirement savings plans total expense	$ 19,419,000	$ 17,690,000

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	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income available to common shareholders:
Net income	$ 348,927	$ 298,528
Less: Preferred stock dividends	(18,237)	(20,318)
Net income available to common equity	330,690	278,210
Less: Income attributable to unvested stock-based compensation awards	(2,128)	(2,466)
Net income available to common shareholders	$ 328,562	$ 275,744
Weighted-average shares outstanding:
Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards	155,463	160,220
Less: Unvested stock-based compensation awards	(1,036)	(1,486)
Weighted-average shares outstanding	154,427	158,734
Basic earnings per common share	$ 2.13	$ 1.74

Earnings Per Common Share - C62

Earnings Per Common Share - Computations of Diluted Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Earnings Per Share [Abstract]
Net income available to common equity	$ 330,690	$ 278,210
Less: Income attributable to unvested stock-based compensation awards	(2,123)	(2,462)
Net income available to common shareholders	$ 328,567	$ 275,748
Adjusted weighted-average shares outstanding:
Common and unvested stock-based compensation awards	155,463	160,220
Less: Unvested stock-based compensation awards	(1,036)	(1,486)
Plus: Incremental shares from assumed conversion of stock-based compensation awards and warrants to purchase common stock	522	447
Adjusted weighted-average shares outstanding	154,949	159,181
Diluted earnings per common share	$ 2.12	$ 1.73

Earnings Per Common Share - Add

Earnings Per Common Share - Additional Information (Detail) - shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Earnings Per Share [Abstract]
Antidilutive securities excluded from computation of earnings per share	391,764	2,840,575

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	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, before tax	$ (485,245)	$ (414,545)
Unrealized holding gains (losses), before tax	(3,015)	159,290
Foreign currency translation adjustment, before tax	732	(83)
Total other comprehensive income (loss) before reclassifications, before tax	(2,283)	159,207
Amortization of unrealized holding losses on held-to-maturity (“HTM”) securities, before tax	787	968
Gains (losses) realized in net income, before tax		(4)
Accretion of net gain (losses) on terminated cash flow hedges, before tax	(39)	(39)
Amortization of prior service credit, before tax	(225)	(1,175)
Amortization of actuarial losses, before tax	6,775	8,300
Total reclassifications, before tax	7,298	8,050
Total gain (loss) during the period, before tax	5,015	167,257
Ending balance, before tax	(480,230)	(247,288)
Beginning balance, tax	190,609	162,918
Unrealized holding gains (losses), tax	1,182	(62,680)
Foreign currency translation adjustment, tax	(256)	30
Total other comprehensive income (loss) before reclassifications, tax	926	(62,650)
Amortization of unrealized holding losses on held-to-maturity (“HTM”) securities, tax	(310)	(381)
Gains (losses) realized in net income, tax		1
Accretion of net gain (losses) on terminated cash flow hedges, tax	16	15
Amortization of prior service credit, tax	88	462
Amortization of actuarial losses, tax	(2,666)	(3,266)
Total reclassifications, tax	(2,872)	(3,169)
Total gain (loss) during the period, tax	(1,946)	(65,819)
Ending balance, tax	188,663	97,099
Beginning balance, net of tax	(294,636)	(251,627)
Unrealized holding gains (losses), net	(1,833)	96,610
Foreign currency translation adjustment, net of tax	476	(53)
Total other comprehensive income (loss) before reclassifications, net of tax	(1,357)	96,557
Amortization of unrealized holding losses on held-to-maturity (“HTM”) securities, net of tax	477	587
Gains (losses) realized in net income, net of tax		(3)
Accretion of net gain on terminated cash flow hedges, net of tax	(23)	(24)
Amortization of prior service credit, net of tax	(137)	(713)
Amortization of actuarial losses, net of tax	4,109	5,034
Total reclassifications, net of tax	4,426	4,881
Total other comprehensive income	3,069	101,438
Ending balance, net of tax	(291,567)	(150,189)
Investment Securities With OTTI [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, before tax	46,725	16,359
Unrealized holding gains (losses), before tax	(8,628)	(370)
Total other comprehensive income (loss) before reclassifications, before tax	(8,628)	(370)
Total gain (loss) during the period, before tax	(8,628)	(370)
Ending balance, before tax	38,097	15,989
Investment Securities All Other [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, before tax	(73,785)	62,849
Unrealized holding gains (losses), before tax	5,613	159,660
Total other comprehensive income (loss) before reclassifications, before tax	5,613	159,660
Amortization of unrealized holding losses on held-to-maturity (“HTM”) securities, before tax	787	968
Gains (losses) realized in net income, before tax		(4)
Total reclassifications, before tax	787	964
Total gain (loss) during the period, before tax	6,400	160,624
Ending balance, before tax	(67,385)	223,473
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, before tax	(449,917)	(489,660)
Amortization of prior service credit, before tax	(225)	(1,175)
Amortization of actuarial losses, before tax	6,775	8,300
Total reclassifications, before tax	6,550	7,125
Total gain (loss) during the period, before tax	6,550	7,125
Ending balance, before tax	(443,367)	(482,535)
Total other comprehensive income	3,972
Other [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, before tax	(8,268)	(4,093)
Foreign currency translation adjustment, before tax	732	(83)
Total other comprehensive income (loss) before reclassifications, before tax	732	(83)
Accretion of net gain (losses) on terminated cash flow hedges, before tax	(39)	(39)
Total reclassifications, before tax	(39)	(39)
Total gain (loss) during the period, before tax	693	(122)
Ending balance, before tax	$ (7,575)	$ (4,215)

Comprehensive Income - Accumula

Comprehensive Income - Accumulated Other Comprehensive Income (Loss), Net (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 16,486,622	$ 16,173,289
Net gain (loss) during period	3,069	101,438
Ending balance	16,213,104	16,355,053
Investment Securities With OTTI [Member] | Investment Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	28,338
Net gain (loss) during period	(5,232)
Ending balance	23,106
Investment Securities All Other [Member] | Investment Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(44,657)
Net gain (loss) during period	3,876
Ending balance	(40,781)
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(272,874)
Net gain (loss) during period	3,972
Ending balance	(268,902)
Accumulated Other Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(5,443)
Net gain (loss) during period	453
Ending balance	(4,990)
Accumulated Other Comprehensive Income (Loss), Net [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(294,636)	(251,627)
Net gain (loss) during period	3,069
Ending balance	$ (291,567)	$ (150,189)

Derivative Financial Instrume66

Derivative Financial Instruments - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
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	$ 24,000,000		$ 28,000,000
Aggregate fair value of derivative financial instruments in a liability position	26,000,000		34,000,000
Net liability positions with counterparties	25,000,000		30,000,000
Aggregate fair value of derivative financial instruments in asset position	14,000,000		15,000,000
Net fair value of derivative financial instruments in a net asset position	13,000,000		11,000,000
Collateral relating to net asset positions	12,000,000		9,000,000
Counterparties [Member]
Derivative [Line Items]
Post collateral requirements relating to positions	23,000,000		27,000,000
Clearinghouse Credit Facilities [Member]
Derivative [Line Items]
Amount of initial margin posted	83,000,000		111,000,000
Net fair value of derivative financial instruments in a net asset position	1,000,000		63,000,000
Collateral relating to net asset positions	1,000,000		81,000,000
Reduction in the fair value of derivative asset due to contractual settlements	(112,000,000)
Reduction in the fair value of derivative liability due to contractual settlements	(25,000,000)
Interest Rate Swap Agreements [Member]
Derivative [Line Items]
Increase in net interest income due to interest rate swap agreements	4,000,000	$ 10,000,000
Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amounts of derivative contracts entered into for trading account purposes	22,300,000,000		21,600,000,000
Foreign Currency and Other Option and Futures Contracts [Member]
Derivative [Line Items]
Notional amounts of derivative contracts entered into for trading account purposes	496,000,000		$ 471,000,000
Credit Risk Derivative [Member]
Derivative [Line Items]
Amount of initial margin posted	0
Fair value of additional collateral to be posted for derivative financial instruments	0
Credit Risk Derivative [Member] | Maximum [Member]
Derivative [Line Items]
Aggregate fair value of derivative financial instruments in a net liability position	$ 1,000,000

Derivative Financial Instrume67

Derivative Financial Instruments - Information about Interest Rate Swap Agreements (Detail) - Fixed Rate Long-Term Borrowings [Member] - Fair Value Hedges [Member] - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Notional Amount	$ 900,000,000	$ 900,000,000
Average Maturity (in years)	9 months 18 days	1 year 1 month 6 days
Weighted-Average Rate, Fixed	3.75%	3.75%
Weighted-Average Rate, Variable	2.24%	2.08%
Estimated Fair Value Gain	$ 7,773,000	$ 11,892,000

Derivative Financial Instrume68

Derivative Financial Instruments - Information about Fair Values of Derivative Instruments in Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	$ 144,199	$ 295,069
Liability Derivatives, Fair Value	143,243	176,857
Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	135,601	249,988
Liability Derivatives, Fair Value	140,922	175,510
Fair Value Hedges [Member] | Derivatives Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	8,598	45,081
Liability Derivatives, Fair Value	2,321	1,347
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	7,773	11,892
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	4,126	5,210
Liability Derivatives, Fair Value	1,582	399
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	825	33,189
Liability Derivatives, Fair Value	2,321	1,347
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	16,847	8,060
Liability Derivatives, Fair Value	645	735
Interest Rate Contracts [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	109,996	228,810
Liability Derivatives, Fair Value	134,919	167,737
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	4,632	7,908
Liability Derivatives, Fair Value	$ 3,776	$ 6,639

Derivative Financial Instrume69

Derivative Financial Instruments - Information about Fair Values of Derivative Instruments in Consolidated Statement of Income (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives not designated as hedging instruments, Derivatives	$ 3,786	$ 2,186
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	(4,119)	(2,633)
Derivatives in fair value hedging relationships, Hedged item	4,012	1,870
Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives not designated as hedging instruments, Derivatives	1,950	974
Foreign Exchange and Other Option and Futures Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives not designated as hedging instruments, Derivatives	$ 1,836	$ 1,212

Variable Interest Entities an70

Variable Interest Entities and Asset Securitizations - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Variable Interest Entity Disclosure [Abstract]
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		1,000,000,000
Maximum exposure to loss of investments in real estate partnerships	316,000,000		294,000,000
Unfunded commitments included in company's maximum exposure to loss of investments in real estate partnerships	114,000,000		$ 102,000,000
Investments amortized to income tax expense	13,000,000	$ 11,000,000
Federal tax credits and other federal tax benefits recognized	$ 16,000,000	$ 14,000,000

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Estimated Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets	$ 174,854	$ 323,867
Investment securities	12,631,000	13,332,072
U.S. Treasury and Federal Agencies [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	1,898,250	1,902,544
Obligations of States and Political Subdivisions [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	3,124	3,641
Government Issued or Guaranteed [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	10,504,314	10,954,861
Other Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	119,767	118,516
Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	105,504	352,466
Fair Value Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets	174,854	323,867
Investment securities	12,631,000	13,332,072
Real estate loans held for sale	372,023	1,056,180
Other assets	29,571	58,351
Total assets	13,207,448	14,770,470
Trading account liabilities	138,695	174,376
Other liabilities	4,548	2,481
Total liabilities	143,243	176,857
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	46,137	46,135
Investment securities	63,698	301,711
Total assets	109,835	347,846
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	128,717	277,732
Investment securities	12,567,261	13,030,317
Real estate loans held for sale	372,023	1,056,180
Other assets	12,724	50,291
Total assets	13,080,725	14,414,520
Trading account liabilities	138,695	174,376
Other liabilities	3,903	1,746
Total liabilities	142,598	176,122
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	41	44
Other assets	16,847	8,060
Total assets	16,888	8,104
Other liabilities	645	735
Total liabilities	645	735
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	1,898,250	1,902,544
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	1,898,250	1,902,544
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	3,124	3,641
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	3,124	3,641
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	10,504,314	10,954,861
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	10,504,314	10,954,861
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	41	44
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	41	44
Fair Value Measurements, Recurring [Member] | Other Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	119,767	118,516
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	119,767	118,516
Fair Value Measurements, Recurring [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	105,504	352,466
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	63,698	301,711
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	$ 41,806	$ 50,755

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	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Privately Issued [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 44	$ 74
Total gains (losses) realized/unrealized:
Settlements	(3)	(9)
Ending Balance	41	65
Other Assets and Other Liabilities [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	7,325	9,879
Total gains (losses) realized/unrealized:
Included in earnings	23,940	23,898
Transfers in and/or out of Level 3 (a)	(15,063)	(16,892)
Ending Balance	16,202	16,885
Changes in unrealized gains included in earnings related to assets still held at end of period	$ 15,094	14,539
Collateralized Debt Obligations [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance		47,393
Total gains (losses) realized/unrealized:
Included in other comprehensive income		(2,148)
Settlements		(205)
Ending Balance		$ 45,040

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount rates for fair value estimations	15.00%
Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount rates for fair value estimations	90.00%
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	$ 42	$ 27
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	210	226	$ 293
Assets taken in foreclosure of defaulted loans measured at fair value on a nonrecurring basis	32	62
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	88	127	153
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	$ 122	$ 99	$ 140

Fair Value Measurements - Quant

Fair Value Measurements - Quantitative Information Related to Significant Unobservable Inputs (Detail) - Fair Value Measurements, Recurring [Member] - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
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	$ 41	$ 44
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	$ 16,202	$ 7,325
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	80.00%	77.00%
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	24.00%	30.00%

Fair Value Measurements - Carry

Fair Value Measurements - Carrying Amounts and Estimated Fair Value for Financial Instrument Assets (Liabilities) (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Financial assets:
Cash and cash equivalents	$ 1,286,962	$ 1,320,549	$ 1,178,175	$ 1,368,040
Interest-bearing deposits at banks	6,945,149	5,000,638
Trading account	174,854	323,867
Investment securities	15,968,415	16,250,468
Loans and leases:
Allowance for credit losses	(1,001,430)	(988,997)	$ (962,752)	$ (955,992)
Loans and leases, net	88,311,572	89,864,419
Financial liabilities:
Noninterest-bearing deposits	(34,279,591)	(32,813,896)
Savings and interest-checking deposits	(53,542,149)	(52,346,207)
Time deposits	(9,028,018)	(10,131,846)
Deposits at Cayman Islands office	(192,763)	(201,927)
Short-term borrowings	(185,102)	(163,442)
Long-term borrowings	(8,087,619)	(9,493,835)
Carrying Amount [Member]
Financial assets:
Cash and cash equivalents	1,286,962	1,320,549
Interest-bearing deposits at banks	6,945,149	5,000,638
Trading account	174,854	323,867
Investment securities	15,968,415	16,250,468
Loans and leases:
Commercial loans and leases	22,295,376	22,610,047
Commercial real estate loans	33,071,654	33,506,394
Residential real estate loans	21,724,491	22,590,912
Consumer loans	12,221,481	12,146,063
Allowance for credit losses	(1,001,430)	(988,997)
Loans and leases, net	88,311,572	89,864,419
Accrued interest receivable	318,152	308,805
Financial liabilities:
Noninterest-bearing deposits	(34,279,591)	(32,813,896)
Savings and interest-checking deposits	(53,542,149)	(52,346,207)
Time deposits	(9,028,018)	(10,131,846)
Deposits at Cayman Islands office	(192,763)	(201,927)
Short-term borrowings	(185,102)	(163,442)
Long-term borrowings	(8,087,619)	(9,493,835)
Accrued interest payable	(60,737)	(75,172)
Trading account	(138,695)	(174,376)
Other financial instruments:
Commitments to originate real estate loans for sale	16,202	7,325
Commitments to sell real estate loans	1,048	36,653
Other credit-related commitments	(129,968)	(136,295)
Interest rate swap agreements used for interest rate risk management	7,773	11,892
Estimate Fair Value [Member]
Financial assets:
Cash and cash equivalents	1,286,962	1,320,549
Interest-bearing deposits at banks	6,945,149	5,000,638
Trading account	174,854	323,867
Investment securities	15,958,181	16,244,412
Loans and leases:
Commercial loans and leases	21,882,456	22,239,428
Commercial real estate loans	32,607,794	33,129,428
Residential real estate loans	21,776,908	22,638,167
Consumer loans	12,083,513	12,061,590
Loans and leases, net	88,350,671	90,068,613
Accrued interest receivable	318,152	308,805
Financial liabilities:
Noninterest-bearing deposits	(34,279,591)	(32,813,896)
Savings and interest-checking deposits	(53,542,149)	(52,346,207)
Time deposits	(9,106,654)	(10,222,585)
Deposits at Cayman Islands office	(192,763)	(201,927)
Short-term borrowings	(185,102)	(163,442)
Long-term borrowings	(8,104,055)	(9,473,844)
Accrued interest payable	(60,737)	(75,172)
Trading account	(138,695)	(174,376)
Other financial instruments:
Commitments to originate real estate loans for sale	16,202	7,325
Commitments to sell real estate loans	1,048	36,653
Other credit-related commitments	(129,968)	(136,295)
Interest rate swap agreements used for interest rate risk management	7,773	11,892
Estimate Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets:
Cash and cash equivalents	1,213,120	1,249,654
Trading account	46,137	46,135
Investment securities	63,698	301,711
Estimate Fair Value [Member] | Significant Observable Inputs (Level 2) [Member]
Financial assets:
Cash and cash equivalents	73,842	70,895
Interest-bearing deposits at banks	6,945,149	5,000,638
Trading account	128,717	277,732
Investment securities	15,775,917	15,821,176
Loans and leases:
Commercial real estate loans	74,563	642,590
Residential real estate loans	4,686,339	4,912,488
Loans and leases, net	4,760,902	5,555,078
Accrued interest receivable	318,152	308,805
Financial liabilities:
Noninterest-bearing deposits	(34,279,591)	(32,813,896)
Savings and interest-checking deposits	(53,542,149)	(52,346,207)
Time deposits	(9,106,654)	(10,222,585)
Deposits at Cayman Islands office	(192,763)	(201,927)
Short-term borrowings	(185,102)	(163,442)
Long-term borrowings	(8,104,055)	(9,473,844)
Accrued interest payable	(60,737)	(75,172)
Trading account	(138,695)	(174,376)
Other financial instruments:
Commitments to sell real estate loans	1,048	36,653
Interest rate swap agreements used for interest rate risk management	7,773	11,892
Estimate Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member]
Financial assets:
Investment securities	118,566	121,525
Loans and leases:
Commercial loans and leases	21,882,456	22,239,428
Commercial real estate loans	32,533,231	32,486,838
Residential real estate loans	17,090,569	17,725,679
Consumer loans	12,083,513	12,061,590
Loans and leases, net	83,589,769	84,513,535
Other financial instruments:
Commitments to originate real estate loans for sale	16,202	7,325
Other credit-related commitments	$ (129,968)	$ (136,295)

Commitments and Contingencies -

Commitments and Contingencies - Company's Significant Commitments (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Commitments to extend credit
Home equity lines of credit	$ 5,535,221	$ 5,499,609
Commercial real estate loans to be sold	298,039	70,100
Other commercial real estate	6,166,511	6,451,709
Residential real estate loans to be sold	473,837	478,950
Other residential real estate	240,430	232,721
Commercial and other	12,134,803	12,298,473
Standby letters of credit	2,937,504	2,987,091
Commercial letters of credit	46,560	44,723
Financial guarantees and indemnification contracts	3,477,006	3,043,580
Commitments to sell real estate loans	$ 1,013,409	$ 1,489,237

Commitments and Contingencies77

Commitments and Contingencies - Additional Information (Detail) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Loss Contingencies [Line Items]
Maximum credit risk for recourse associated with loans sold under Federal National Mortgage Association Delegated Underwriting and Servicing program	$ 3,000,000,000	$ 2,800,000,000
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

Segment Information - Additiona

Segment Information - Additional Information (Detail) - Hudson City [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)
Discretionary Portfolio [Member]
Segment Reporting Information [Line Items]
Increase (decrease) in total revenues	$ 14
Increase (decrease) in net income	8
All Other [Member]
Segment Reporting Information [Line Items]
Increase (decrease) in total revenues	(14)
Increase (decrease) in net income	$ (8)

Segment Information - Informati

Segment Information - Information about Company's Segments (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Net Income (Loss)	$ 348,927	$ 298,528
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	1,361,105	1,292,897
Business Banking [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)	22,407	25,448
Business Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	115,981	113,689
Business Banking [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total Revenues	911	991
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)	112,750	101,327
Commercial Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	273,845	253,617
Commercial Banking [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total Revenues	920	1,056
Commercial Real Estate [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)	84,547	80,529
Commercial Real Estate [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	195,125	177,380
Commercial Real Estate [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total Revenues	407	387
Discretionary Portfolio [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)	33,945	48,410
Discretionary Portfolio [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	78,946	101,036
Discretionary Portfolio [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total Revenues	(12,927)	(14,323)
Residential Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)	14,844	17,077
Residential Mortgage Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	93,708	96,935
Residential Mortgage Banking [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total Revenues	18,211	19,660
Retail Banking [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)	81,873	63,288
Retail Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	361,237	339,046
Retail Banking [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total Revenues	3,047	3,014
All Other [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)	(1,439)	(37,551)
All Other [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	242,263	211,194
All Other [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total Revenues	$ (10,569)	$ (10,785)

Segment Information - Summary o

Segment Information - Summary of Segment Information (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Segment Reporting Information [Line Items]
Average Assets	$ 122,978	$ 124,340	$ 123,252
Business Banking [Member]
Segment Reporting Information [Line Items]
Average Assets	5,596	5,456	5,424
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Average Assets	26,723	25,592	24,838
Commercial Real Estate [Member]
Segment Reporting Information [Line Items]
Average Assets	22,977	21,131	19,839
Discretionary Portfolio [Member]
Segment Reporting Information [Line Items]
Average Assets	38,731	40,867	42,509
Residential Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Average Assets	2,426	2,569	2,647
Retail Banking [Member]
Segment Reporting Information [Line Items]
Average Assets	12,204	11,840	11,568
All Other [Member]
Segment Reporting Information [Line Items]
Average Assets	$ 14,321	$ 16,885	$ 16,427

Segment Information - Summary81

Segment Information - Summary of Segment Information (Parenthetical) (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting [Abstract]
Taxable-equivalent adjustment	$ 7,999,000	$ 6,332,000

Relationship with Bayview Len82

Relationship with Bayview Lending Group LLC and Bayview Financial Holdings, L.P. - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Apr. 28, 2017	Dec. 31, 2016
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	$ 364
Bayview Lending Group and Bayview Financial [Member]
Schedule of Equity Method Investments [Line Items]
Outstanding principal balances of mortgage servicing rights	3,400			$ 3,500
Revenues from servicing	4	$ 5
Bayview Financial [Member]
Schedule of Equity Method Investments [Line Items]
Outstanding principal balances of residential mortgage loans from Bayview Financial	40,800			30,400
Revenues from sub-servicing	23	$ 23
Investment securities in held-to-maturity portfolio securitized by Bayview Financial	$ 153			$ 158
Bayview Financial [Member] | Subsequent Event [Member]
Schedule of Equity Method Investments [Line Items]
Loan to Bayview Financial			$ 100

Recent Accounting Developments

Recent Accounting Developments - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Minimum lease payments under non cancelable operating lease		$ 467
Adoption of New Accounting Guidance [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Reduction of Income tax expense	$ (18)