M&T Bank (MTB) 10-Q 4 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Oct. 28, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3
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		155,048,618

Consolidated Balance Sheet (Una

Consolidated Balance Sheet (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Assets
Cash and due from banks	$ 1,332,202	$ 1,368,040
Interest-bearing deposits at banks	10,777,636	7,594,350
Trading account	488,588	273,783
Investment securities (includes pledged securities that can be sold or repledged of $1,856,326 at September 30, 2016; $2,136,712 at December 31, 2015)
Available for sale (cost: $11,551,614 at September 30, 2016;$12,138,636 at December 31, 2015)	11,862,567	12,242,671
Held to maturity (fair value: $2,456,097 at September 30, 2016; $2,864,147 at December 31, 2015)	2,409,950	2,859,709
Other (fair value: $461,057 at September 30, 2016; $554,059 at December 31, 2015)	461,057	554,059
Total investment securities	14,733,574	15,656,439
Loans and leases	89,887,257	87,719,234
Unearned discount	(240,765)	(229,735)
Loans and leases, net of unearned discount	89,646,492	87,489,499
Allowance for credit losses	(976,121)	(955,992)
Loans and leases, net	88,670,371	86,533,507
Premises and equipment	660,381	666,682
Goodwill	4,593,112	4,593,112
Core deposit and other intangible assets	106,744	140,268
Accrued interest and other assets	5,478,420	5,961,703
Total assets	126,841,028	122,787,884
Liabilities
Noninterest-bearing deposits	33,127,627	29,110,635
Interest-checking deposits	2,554,507	2,939,274
Savings deposits	50,510,523	46,627,370
Time deposits	11,721,005	13,110,392
Deposits at Cayman Islands office	223,183	170,170
Total deposits	98,136,845	91,957,841
Federal funds purchased and agreements to repurchase securities	213,846	150,546
Other short-term borrowings		1,981,636
Accrued interest and other liabilities	1,938,201	1,870,714
Long-term borrowings	10,211,160	10,653,858
Total liabilities	110,500,052	106,614,595
Shareholders’ equity
Preferred stock, $1.00 par, 1,000,000 shares authorized; Issued and outstanding: Liquidation preference of $1,000 per share: 731,500 shares at September 30, 2016 and December 31,2015; Liquidation preference of $10,000 per share: 50,000 shares at September 30, 2016 and December 31, 2015	1,231,500	1,231,500
Common stock, $.50 par, 250,000,000 shares authorized, 159,950,278 shares issued at September 30, 2016; 159,563,512 shares issued at December 31, 2015	79,975	79,782
Common stock issuable, 33,748 shares at September 30, 2016; 36,644 shares at December 31, 2015	2,224	2,364
Additional paid-in capital	6,689,812	6,680,768
Retained earnings	9,021,965	8,430,502
Accumulated other comprehensive income (loss), net	(114,559)	(251,627)
Treasury stock - common, at cost - 4,997,089 shares at September 30, 2016	(569,941)
Total shareholders' equity	16,340,976	16,173,289
Total liabilities and shareholders' equity	$ 126,841,028	$ 122,787,884

Consolidated Balance Sheet (Un3

Consolidated Balance Sheet (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Pledged securities that can be sold or repledged	$ 1,856,326	$ 2,136,712
Investment securities, available for sale, amortized cost	11,551,614	12,138,636
Investment securities, held to maturity, fair value	2,456,097	2,864,147
Other, fair value	$ 461,057	$ 554,059
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	1,000,000	1,000,000
Common stock, par value	$ 0.50	$ 0.50
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	159,950,278	159,563,512
Common stock issuable, shares	33,748	36,644
Treasury stock, shares	4,997,089
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		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Interest income
Loans and leases, including fees	$ 871,345	$ 672,092	$ 2,602,208	$ 1,981,904
Investment securities
Fully taxable	84,893	93,062	274,092	272,163
Exempt from federal taxes	623	950	2,081	3,330
Deposits at banks	12,354	3,852	33,684	10,321
Other	300	70	905	749
Total interest income	969,515	770,026	2,912,970	2,268,467
Interest expense
Interest-checking deposits	378	360	1,192	1,020
Savings deposits	23,689	10,937	59,714	31,517
Time deposits	27,886	3,643	79,075	11,073
Deposits at Cayman Islands office	204	151	578	448
Short-term borrowings	169	32	3,474	102
Long-term borrowings	58,849	62,076	174,814	188,764
Total interest expense	111,175	77,199	318,847	232,924
Net interest income	858,340	692,827	2,594,123	2,035,543
Provision for credit losses	47,000	44,000	128,000	112,000
Net interest income after provision for credit losses	811,340	648,827	2,466,123	1,923,543
Other income
Mortgage banking revenues	103,747	84,035	275,193	288,238
Service charges on deposit accounts	107,935	107,259	314,212	314,860
Trust income	118,654	113,744	350,181	356,076
Brokerage services income	15,914	16,902	48,190	49,224
Trading account and foreign exchange gains	12,754	8,362	33,434	20,639
Gain (loss) on bank investment securities	28,480		28,748	(108)
Other revenues from operations	103,866	109,397	310,579	348,000
Total other income	491,350	439,699	1,360,537	1,376,929
Other expense
Salaries and employee benefits	399,786	363,567	1,230,246	1,115,117
Equipment and net occupancy	75,263	68,470	225,165	201,792
Printing, postage and supplies	8,972	8,691	30,865	27,586
Amortization of core deposit and other intangible assets	9,787	4,090	33,524	16,848
FDIC assessments	28,459	11,090	76,054	32,551
Other costs of operations	230,125	197,908	682,528	642,925
Total other expense	752,392	653,816	2,278,382	2,036,819
Income before taxes	550,298	434,710	1,548,278	1,263,653
Income taxes	200,314	154,309	563,735	454,951
Net income	349,984	280,401	984,543	808,702
Net income available to common shareholders
Basic	326,992	257,337	915,670	739,627
Diluted	$ 326,998	$ 257,346	$ 915,686	$ 739,656
Net income per common share
Basic	$ 2.10	$ 1.94	$ 5.82	$ 5.59
Diluted	2.10	1.93	5.80	5.56
Cash dividends per common share	$ 0.70	$ 0.70	$ 2.10	$ 2.10
Average common shares outstanding
Basic	155,493	132,630	157,336	132,347
Diluted	156,026	133,376	157,843	133,089

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement Of Partners Capital [Abstract]
Net income	$ 349,984	$ 280,401	$ 984,543	$ 808,702
Other comprehensive income (loss), net of tax and reclassification adjustments:
Net unrealized gains (losses) on investment securities	(17,133)	48,332	127,331	1,053
Cash flow hedges adjustments	(23)	(24)	(70)	823
Foreign currency translation adjustment	(229)	(3)	(1,847)	(521)
Defined benefit plans liability adjustments	3,847	5,724	11,654	16,166
Total other comprehensive income (loss)	(13,538)	54,029	137,068	17,521
Total comprehensive income	$ 336,446	$ 334,430	$ 1,121,611	$ 826,223

Consolidated Statement of Cash

Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities
Net income	$ 984,543	$ 808,702
Adjustments to reconcile net income to net cash provided by operating activities
Provision for credit losses	128,000	112,000
Depreciation and amortization of premises and equipment	79,911	73,916
Amortization of capitalized servicing rights	37,979	36,730
Amortization of core deposit and other intangible assets	33,524	16,848
Provision for deferred income taxes	109,274	20,141
Asset write-downs	14,276	5,775
Net gain on sales of assets	(46,732)	(61,969)
Net change in accrued interest receivable, payable	(13,833)	(5,484)
Net change in other accrued income and expense	113,809	11,200
Net change in loans originated for sale	(285,824)	232,974
Net change in trading account assets and liabilities	(82,837)	(2,993)
Net cash provided by operating activities	1,072,090	1,247,840
Cash flows from investing activities
Proceeds from sales of investment securities Available for sale	61,947	2,579
Proceeds from sales of investment securities Other	94,516	377
Proceeds from maturities of investment securities Available for sale	1,690,665	1,343,869
Proceeds from maturities of investment securities Held to maturity	459,399	519,359
Purchases of investment securities Available for sale	(1,150,523)	(3,320,931)
Purchases of investment securities Held to maturity	(15,806)	(22,592)
Purchases of investment securities Other	(1,514)	(8,179)
Net increase in loans and leases	(2,021,004)	(2,208,660)
Net (increase) decrease in interest-bearing deposits at banks	(3,183,286)	1,757,601
Capital expenditures, net	(65,277)	(42,744)
Net decrease in loan servicing advances	121,226	461,700
Other, net	11,459	(75,449)
Net cash used by investing activities	(3,998,198)	(1,593,070)
Cash flows from financing activities
Net increase (decrease) in deposits	6,195,511	(636,144)
Net decrease in short-term borrowings	(1,886,701)	(18,893)
Proceeds from long-term borrowings		1,500,000
Payments on long-term borrowings	(427,035)	(324,308)
Purchases of treasury stock	(604,000)
Dividends paid - common	(333,042)	(281,149)
Dividends paid - preferred	(58,003)	(58,003)
Other, net	3,540	40,074
Net cash provided by financing activities	2,890,270	221,577
Net decrease in cash and cash equivalents	(35,838)	(123,653)
Cash and cash equivalents at beginning of period	1,368,040	1,373,357
Cash and cash equivalents at end of period	1,332,202	1,249,704
Supplemental disclosure of cash flow information
Interest received during the period	2,923,278	2,234,476
Interest paid during the period	387,695	234,989
Income taxes paid during the period	138,375	373,016
Supplemental schedule of noncash investing and financing activities
Real estate acquired in settlement of loans	100,106	35,018
Securitization of residential mortgage loans allocated to Available-for-sale investment securities	18,685	51,481
Securitization of residential mortgage loans allocated to capitalized servicing rights	$ 193	$ 528

Consolidated Statement of Chang

Consolidated Statement of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Common Stock [Member]Series A Warrants [Member]	Common Stock Issuable [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member]Series 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, 2014	$ 12,335,896	$ 1,231,500	$ 66,157		$ 2,608	$ 3,409,506		$ 7,807,119	$ (180,994)
Total comprehensive income	826,223							808,702	17,521
Preferred stock cash dividends	(60,953)							(60,953)
Exercise of stock warrants into common stock				$ 1			$ (1)
Stock-based compensation plans:
Compensation expense, net	31,559		143			31,416
Exercises of stock options, net	57,418		285			57,133
Stock purchase plan	10,346		45			10,301
Directors' stock plan	1,350		4			1,346
Deferred compensation plans, net, including dividend equivalents	(51)		2		(267)	290		(76)
Other	1,191					1,191
Common stock cash dividends - $2.10 per share	(281,045)							(281,045)
Ending balance at Sep. 30, 2015	12,921,934	1,231,500	66,637		2,341	3,511,182		8,273,747	(163,473)
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	1,121,611							984,543	137,068
Preferred stock cash dividends	(60,953)							(60,953)
Exercise of stock warrants into common stock							$ (223)				$ 223
Purchases of treasury stock	(604,000)									$ (604,000)
Stock-based compensation plans:
Compensation expense, net	18,376		171			7,315				10,890
Exercises of stock options, net	11,411		18			(183)				11,576
Stock purchase plan	10,594					275				10,319
Directors' stock plan	1,575		2			526				1,047
Deferred compensation plans, net, including dividend equivalents	28		2		(140)	232		(70)		4
Other	1,102					1,102
Common stock cash dividends - $2.10 per share	(332,057)							(332,057)
Ending balance at Sep. 30, 2016	$ 16,340,976	$ 1,231,500	$ 79,975		$ 2,224	$ 6,689,812		$ 9,021,965	$ (114,559)	$ (569,941)

Consolidated Statement of Chan8

Consolidated Statement of Changes in Shareholders' Equity (Unaudited) (Parenthetical) - $ / shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Common stock per share dividend amount	$ 0.70	$ 0.70	$ 2.10	$ 2.10
Common Stock [Member] | Series A Warrants [Member]
Exercise of warrants into shares of common stock		2,315		2,315
Exercise of warrants into shares of common stock				904
Retained Earnings [Member]
Common stock per share dividend amount			$ 2.10	$ 2.10
Treasury Stock [Member] | Series A Warrants [Member]
Exercise of warrants into shares of common stock	5,320		5,320
Exercise of warrants into shares of common stock			1,983

Significant accounting policies

Significant accounting policies	9 Months Ended
	Sep. 30, 2016
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, 2015 (“2015 Annual Report”). 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	9 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Acquisitions	2. Acquisitions On November 1, 2015, M&T completed the acquisition of Hudson City Bancorp, Inc. (“Hudson City”), headquartered in Paramus, New Jersey. On that date, Hudson City Savings Bank, the banking subsidiary of Hudson City, was merged into M&T Bank, a wholly owned banking subsidiary of M&T. Hudson City Savings Bank operated 135 banking offices in New Jersey, Connecticut and New York at the date of acquisition. The results of operations acquired in the Hudson City transaction have been included in the Company’s financial results since November 1, 2015. After application of the election, allocation and proration procedures contained in the merger agreement with Hudson City, M&T paid $2.1 billion in cash and issued 25,953,950 shares of M&T common stock in exchange for Hudson City shares outstanding at the time of the acquisition. The purchase price was approximately $5.2 billion based on the cash paid to Hudson City shareholders, the fair value of M&T stock exchanged and the estimated fair value of Hudson City stock awards converted into M&T stock awards. The acquisition of Hudson City expanded the Company’s presence in New Jersey, Connecticut and New York, and management expects that the Company will benefit from greater geographic diversity and the advantages of scale associated with a larger company. The Hudson City transaction has been accounted for using the acquisition method of accounting and, accordingly, assets acquired, liabilities assumed and consideration exchanged were recorded at estimated fair value on the acquisition date. The consideration paid for Hudson City’s common equity and the amounts of identifiable assets acquired and liabilities assumed as of the acquisition date were as follows: (in thousands) Identifiable assets: Cash and due from banks $ 131,688 Interest-bearing deposits at banks 7,568,934 Investment securities 7,929,014 Loans 19,015,013 Goodwill 1,079,787 Core deposit intangible 131,665 Other assets 843,219 Total identifiable assets 36,699,320 Liabilities: Deposits 17,879,589 Borrowings 13,211,598 Other liabilities 405,025 Total liabilities 31,496,212 Total consideration $ 5,203,108 Cash paid $ 2,064,284 Common stock issued (25,953,950 shares) 3,110,581 Common stock awards converted 28,243 Total consideration $ 5,203,108 In early November 2015, the Company sold $5.8 billion of investment securities obtained in the acquisition and repaid $10.6 billion of borrowings assumed in the transaction. In connection with the acquisition, the Company recorded approximately $1.1 billion of goodwill and $132 million of core deposit intangible. The core deposit intangible asset is being amortized over a period of 7 years using an accelerated method. 2. Acquisitions, continued The following table presents certain pro forma information as if Hudson City had been included in the Company’s results of operations in the three-month and nine-month periods ended September 30, 2015. These results combine the historical results of Hudson City into the Company’s consolidated statement of income and, while certain adjustments were made for the estimated impact of certain fair valuation adjustments and other acquisition-related activity, they are not indicative of what would have occurred had the acquisition taken place as indicated. In particular, no adjustments have been made to eliminate the impact of gains on securities transactions of $23 million during the three months ended September 30, 2015 and $97 million during the nine months ended September 30, 2015 that may not have been recognized had the investment securities been recorded at fair value. Additionally, the Company expects to achieve operating cost savings and other business synergies as a result of the acquisition which are not reflected in the pro forma amounts that follow. Pro forma Pro forma Three months ended September 30, Nine months ended September 30, 2015 2015 (in thousands) Total revenues (a) $ 1,255,165 3,879,204 Net income 296,335 939,226 (a) Represents net interest income plus other income. In connection with the Hudson City acquisition, the Company incurred merger-related expenses related to systems conversions and other costs of integrating and conforming acquired operations with and into the Company. Those expenses consisted largely of professional services and other temporary help fees associated with preparing for systems conversions and/or integration of operations; costs related to termination of existing contractual arrangements for various services; initial marketing and promotion expenses designed to introduce M&T Bank to its new customers; severance (for former Hudson City employees); travel costs; and other costs of completing the transaction and commencing operations in new markets and offices. The Company does not expect additional merger-related expenses in 2016. A summary of merger-related expenses included in the consolidated statement of income follows: Nine months ended September 30, 2016 (in thousands) Salaries and employee benefits $ 5,334 Equipment and net occupancy 1,278 Printing, postage and supplies 1,482 Other cost of operations 27,661 Total $ 35,755 There were no merger-related expenses during the three-month period ended September 30, 2016 or during the three-month and nine-month periods ended September 30, 2015.

Investment securities

Investment securities	9 Months Ended
	Sep. 30, 2016
Investments Debt And Equity Securities [Abstract]
Investment securities	3. Investment securities The amortized cost and estimated fair value of investment securities were as follows: Amortized cost Gross unrealized gains Gross unrealized losses Estimated fair value (in thousands) September 30, 2016 Investment securities available for sale: U.S. Treasury and federal agencies $ 724,540 1,864 3 $ 726,401 Obligations of states and political subdivisions 4,912 108 5 5,015 Mortgage-backed securities: Government issued or guaranteed 10,617,605 314,088 1,031 10,930,662 Privately issued 52 — 1 51 Other debt securities 134,393 1,802 17,969 118,226 Equity securities 70,112 12,363 263 82,212 11,551,614 330,225 19,272 11,862,567 Investment securities held to maturity: Obligations of states and political subdivisions 72,258 458 220 72,496 Mortgage-backed securities: Government issued or guaranteed 2,168,460 83,630 215 2,251,875 Privately issued 163,489 1,616 39,122 125,983 Other debt securities 5,743 — — 5,743 2,409,950 85,704 39,557 2,456,097 Other securities 461,057 — — 461,057 Total $ 14,422,621 415,929 58,829 $ 14,779,721 December 31, 2015 Investment securities available for sale: U.S. Treasury and federal agencies $ 299,890 294 187 $ 299,997 Obligations of states and political subdivisions 5,924 146 42 6,028 Mortgage-backed securities: Government issued or guaranteed 11,592,959 142,370 48,701 11,686,628 Privately issued 74 2 2 74 Collateralized debt obligations 28,438 20,143 1,188 47,393 Other debt securities 137,556 1,514 20,190 118,880 Equity securities 73,795 10,230 354 83,671 12,138,636 174,699 70,664 12,242,671 Investment securities held to maturity: Obligations of states and political subdivisions 118,431 1,003 421 119,013 Mortgage-backed securities: Government issued or guaranteed 2,553,612 50,936 7,817 2,596,731 Privately issued 181,091 2,104 41,367 141,828 Other debt securities 6,575 — — 6,575 2,859,709 54,043 49,605 2,864,147 Other securities 554,059 — — 554,059 Total $ 15,552,404 228,742 120,269 $ 15,660,877 3. Investment securities, During the three months ended September 30, 2016, the Company sold substantially all of its collateralized debt obligations held in the available-for-sale investment securities portfolio for a gain of $28 million. There were no other significant gross realized gains or losses from sales of investment securities for the three-month and nine-month periods ended September 30, 2016 and 2015. At September 30, 2016, the amortized cost and estimated fair value of debt securities by contractual maturity were as follows: Amortized cost Estimated fair value (in thousands) Debt securities available for sale: Due in one year or less $ 105,225 105,679 Due after one year through five years 625,911 627,585 Due after five years through ten years 3,968 4,538 Due after ten years 128,741 111,840 863,845 849,642 Mortgage-backed securities available for sale 10,617,657 10,930,713 $ 11,481,502 11,780,355 Debt securities held to maturity: Due in one year or less $ 25,141 25,301 Due after one year through five years 43,474 43,474 Due after five years through ten years 3,643 3,721 Due after ten years 5,743 5,743 78,001 78,239 Mortgage-backed securities held to maturity 2,331,949 2,377,858 $ 2,409,950 2,456,097 3. Investment securities, A summary of investment securities that as of September 30, 2016 and December 31, 2015 had been in a continuous unrealized loss position for less than twelve months and those that had been in a continuous unrealized loss position for twelve months or longer follows: Less than 12 months 12 months or more Fair value Unrealized losses Fair value Unrealized losses (in thousands) September 30, 2016 Investment securities available for sale: U.S. Treasury and federal agencies $ 3,355 (3 ) — — Obligations of states and political subdivisions — — 472 (5 ) Mortgage-backed securities: Government issued or guaranteed 224,128 (904 ) 7,294 (127 ) Privately issued — — 34 (1 ) Other debt securities — — 106,876 (17,969 ) Equity securities 767 (101 ) 138 (162 ) 228,250 (1,008 ) 114,814 (18,264 ) Investment securities held to maturity: Obligations of states and political subdivisions 19,557 (113 ) 11,050 (107 ) Mortgage-backed securities: Government issued or guaranteed 74,629 (46 ) 19,256 (169 ) Privately issued 17,542 (2,371 ) 91,127 (36,751 ) 111,728 (2,530 ) 121,433 (37,027 ) Total $ 339,978 (3,538 ) 236,247 (55,291 ) December 31, 2015 Investment securities available for sale: U.S. Treasury and federal agencies $ 147,508 (187 ) — — Obligations of states and political subdivisions 865 (2 ) 1,335 (40 ) Mortgage-backed securities: Government issued or guaranteed 4,061,899 (48,534 ) 7,216 (167 ) Privately issued — — 43 (2 ) Collateralized debt obligations 5,711 (335 ) 2,063 (853 ) Other debt securities 12,935 (462 ) 93,344 (19,728 ) Equity securities 18,073 (207 ) 153 (147 ) 4,246,991 (49,727 ) 104,154 (20,937 ) Investment securities held to maturity: Obligations of states and political subdivisions 42,913 (335) 5,853 (86) Mortgage-backed securities: Government issued or guaranteed 459,983 (1,801 ) 228,867 (6,016 ) Privately issued — — 112,155 (41,367 ) 502,896 (2,136 ) 346,875 (47,469 ) Total $ 4,749,887 (51,863 ) 451,029 (68,406 ) The Company owned 504 individual investment securities with aggregate gross unrealized losses of $59 million at September 30, 2016. Based on a review of each of the securities in the investment securities portfolio at September 30, 2016, the Company concluded that it expected to recover the amortized cost basis of its investment. As of September 30, 2016, the Company does not intend to sell nor is it anticipated that it would be required to sell any of its impaired investment securities at a loss. At September 30, 2016, the Company has not identified events or changes in circumstances which may have a significant adverse effect on the fair value of the $461 million of cost method investment securities.

Loans and leases and the allowa

Loans and leases and the allowance for credit losses	9 Months Ended
	Sep. 30, 2016
Receivables [Abstract]
Loans and leases and the allowance for credit losses	4. Loans and leases and the allowance for credit losses 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: September 30, December 31, 2016 2015 (in thousands) Outstanding principal balance $ 2,556,085 3,122,935 Carrying amount: Commercial, financial, leasing, etc. 62,244 78,847 Commercial real estate 504,406 644,284 Residential real estate 845,976 1,016,129 Consumer 609,400 725,807 $ 2,022,026 2,465,067 Purchased impaired loans included in the table above totaled $617 million at September 30, 2016 and $768 million at December 31, 2015, representing less than 1% of the Company’s assets as of each date. A summary of changes in the accretable yield for loans acquired at a discount for the three months and nine months ended September 30, 2016 and 2015 follows: Three months ended September 30 2016 2015 Purchased Other Purchased Other impaired acquired impaired acquired (in thousands) Balance at beginning of period $ 162,023 245,195 $ 77,624 344,989 Interest income (12,784 ) (26,540 ) (5,865 ) (37,396 ) Reclassifications from nonaccretable balance 2,256 12,050 47 769 Other (a) — (818 ) — 4,697 Balance at end of period $ 151,495 229,887 $ 71,806 313,059 Nine months ended September 30 2016 2015 Purchased Other Purchased Other impaired acquired impaired acquired (in thousands) Balance at beginning of period $ 184,618 296,434 $ 76,518 397,379 Interest income (40,906 ) (97,300 ) (16,843 ) (118,697 ) Reclassifications from nonaccretable balance 7,783 20,647 12,131 27,792 Other (a) — 10,106 — 6,585 Balance at end of period $ 151,495 229,887 $ 71,806 313,059 (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 A summary of current, past due and nonaccrual loans as of September 30, 2016 and December 31, 2015 follows: Current 30-89 days past due Accruing loans past due 90 days or more (a) Accruing loans acquired at a discount past due 90 days or more (b) Purchased impaired (c) Nonaccrual Total September 30, 2016 (in thousands) Commercial, financial, leasing, etc. $ 21,601,646 70,597 10,831 1,893 795 231,401 $ 21,917,163 Real estate: Commercial 24,283,146 116,651 15,926 13,292 32,775 157,527 24,619,317 Residential builder and developer 1,814,299 16,993 4,476 3,262 18,096 20,118 1,877,244 Other commercial construction 5,525,684 20,238 — 198 15,412 20,669 5,582,201 Residential 18,438,396 494,767 281,023 12,510 401,551 213,896 19,842,143 Residential-limited documentation 3,400,578 105,621 — — 146,722 89,356 3,742,277 Consumer: Home equity lines and loans 5,586,704 40,406 — 13,014 1,640 79,623 5,721,387 Automobile 2,805,779 46,347 — 4 — 14,453 2,866,583 Other 3,410,790 31,033 5,026 21,009 — 10,319 3,478,177 Total $ 86,867,022 942,653 317,282 65,182 616,991 837,362 $ 89,646,492 December 31, 2015 Commercial, financial, leasing, etc. $ 20,122,648 52,868 2,310 693 1,902 241,917 $ 20,422,338 Real estate: Commercial (d) 23,111,673 172,439 12,963 8,790 46,790 179,606 23,532,261 Residential builder and developer 1,507,856 7,969 5,760 6,925 28,734 28,429 1,585,673 Other commercial construction (d) 3,962,620 65,932 7,936 2,001 24,525 16,363 4,079,377 Residential 20,507,551 560,312 284,451 16,079 488,599 153,281 22,010,273 Residential-limited documentation 3,885,073 137,289 — — 175,518 61,950 4,259,830 Consumer: Home equity lines and loans 5,805,222 45,604 — 15,222 2,261 84,467 5,952,776 Automobile 2,446,473 56,181 — 6 — 16,597 2,519,257 Other 3,051,435 36,702 4,021 18,757 — 16,799 3,127,714 Total $ 84,400,551 1,135,296 317,441 68,473 768,329 799,409 $ 87,489,499 (a) Excludes loans acquired at a discount. (b) Loans acquired at a discount that were recorded at fair value at acquisition date. This category does not include purchased impaired loans that are presented separately. (c) Accruing loans acquired at a discount that were impaired at acquisition date and recorded at fair value. (d) The Company expanded its definition of construction loans in 2016 and, as a result, re-characterized certain commercial real estate loans as other commercial construction loans. The December 31, 2015 balances reflect such changes. One-to-four family residential mortgage loans held for sale were $415 million and $353 million at September 30, 2016 and December 31, 2015, respectively. Commercial mortgage loans held for sale were $290 million at September 30, 2016 and $39 million at December 31, 2015. 4. Loans and leases and the allowance for credit losses, continued Changes in the allowance for credit losses for the three months ended September 30, 2016 were as follows: Commercial, Financial, Real Estate Leasing, etc. Commercial Residential Consumer Unallocated Total (in thousands) Beginning balance $ 316,079 349,674 69,660 157,361 77,722 $ 970,496 Provision for credit losses 26,222 9,963 (6,232 ) 16,539 508 47,000 Net charge-offs Charge-offs (21,075 ) (1,564 ) (6,754 ) (29,882 ) — (59,275 ) Recoveries 6,958 1,704 1,919 7,319 — 17,900 Net charge-offs (14,117 ) 140 (4,835 ) (22,563 ) — (41,375 ) Ending balance $ 328,184 359,777 58,593 151,337 78,230 $ 976,121 Changes in the allowance for credit losses for the three months ended September 30, 2015 were as follows: Commercial, Financial, Real Estate Leasing, etc. Commercial Residential Consumer Unallocated Total (in thousands) Beginning balance $ 286,750 311,294 60,294 194,238 77,411 $ 929,987 Provision for credit losses 21,507 1,879 (3,155 ) 24,448 (679 ) 44,000 Net charge-offs Charge-offs (26,912 ) (2,203 ) (3,268 ) (20,758 ) — (53,141 ) Recoveries 5,322 2,119 1,125 4,386 — 12,952 Net charge-offs (21,590 ) (84 ) (2,143 ) (16,372 ) — (40,189 ) Ending balance $ 286,667 313,089 54,996 202,314 76,732 $ 933,798 Changes in the allowance for credit losses for the nine months ended September 30, 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 39,667 29,799 (610 ) 59,113 31 128,000 Net charge-offs Charge-offs (34,711 ) (3,569 ) (18,816 ) (107,761 ) — (164,857 ) Recoveries 22,824 6,716 5,781 21,665 — 56,986 Net charge-offs (11,887 ) 3,147 (13,035 ) (86,096 ) — (107,871 ) Ending balance $ 328,184 359,777 58,593 151,337 78,230 $ 976,121 Changes in the allowance for credit losses for the nine months ended September 30, 2015 were as follows: Commercial, Financial, Real Estate Leasing, etc. Commercial Residential Consumer Unallocated Total (in thousands) Beginning balance $ 288,038 307,927 61,910 186,033 75,654 $ 919,562 Provision for credit losses 32,686 13,769 (571 ) 65,038 1,078 112,000 Net charge-offs Charge-offs (46,990 ) (12,352 ) (9,695 ) (64,542 ) — (133,579 ) Recoveries 12,933 3,745 3,352 15,785 — 35,815 Net charge-offs (34,057 ) (8,607 ) (6,343 ) (48,757 ) — (97,764 ) Ending balance $ 286,667 313,089 54,996 202,314 76,732 $ 933,798 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 loan 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 September 30, 2016 and December 31, 2015 and for the three-month and nine-month periods ended September 30, 2016 and 2015. September 30, 2016 December 31, 2015 Recorded investment Unpaid principal balance Related allowance Recorded investment Unpaid principal balance Related allowance (in thousands) With an allowance recorded: Commercial, financial, leasing, etc. $ 192,805 212,009 55,020 179,037 195,821 44,752 Real estate: Commercial 75,749 85,137 14,939 85,974 95,855 18,764 Residential builder and developer 8,142 8,923 714 3,316 5,101 196 Other commercial construction 2,729 3,092 1,103 3,548 3,843 348 Residential 79,036 97,466 3,144 79,558 96,751 4,727 Residential-limited documentation 83,296 97,984 6,200 90,356 104,251 8,000 Consumer: Home equity lines and loans 42,862 46,844 7,697 25,220 26,195 3,777 Automobile 18,033 19,218 3,737 22,525 22,525 4,709 Other 4,122 5,122 864 17,620 17,620 4,820 506,774 575,795 93,418 507,154 567,962 90,093 With no related allowance recorded: Commercial, financial, leasing, etc. 72,429 80,757 — 93,190 110,735 — Real estate: Commercial 90,425 104,508 — 101,340 116,230 — Residential builder and developer 17,346 23,617 — 27,651 47,246 — Other commercial construction 18,265 37,432 — 13,221 31,477 — Residential 18,079 26,127 — 19,621 30,940 — Residential-limited documentation 17,611 27,936 — 18,414 31,113 — 234,155 300,377 — 273,437 367,741 — Total: Commercial, financial, leasing, etc. 265,234 292,766 55,020 272,227 306,556 44,752 Real estate: Commercial 166,174 189,645 14,939 187,314 212,085 18,764 Residential builder and developer 25,488 32,540 714 30,967 52,347 196 Other commercial construction 20,994 40,524 1,103 16,769 35,320 348 Residential 97,115 123,593 3,144 99,179 127,691 4,727 Residential-limited documentation 100,907 125,920 6,200 108,770 135,364 8,000 Consumer: Home equity lines and loans 42,862 46,844 7,697 25,220 26,195 3,777 Automobile 18,033 19,218 3,737 22,525 22,525 4,709 Other 4,122 5,122 864 17,620 17,620 4,820 Total $ 740,929 876,172 93,418 780,591 935,703 90,093 4. Loans and leases and the allowance for credit losses, continued Three months ended September 30, 2016 Three months ended September 30, 2015 Interest income recognized Interest income recognized Average recorded investment Total Cash basis Average recorded investment Total Cash basis (in thousands) Commercial, financial, leasing, etc. $ 262,796 744 744 242,157 1,017 1,017 Real estate: Commercial 175,256 1,806 1,806 179,327 2,327 2,327 Residential builder and developer 26,996 405 405 53,009 81 81 Other commercial construction 21,500 190 190 17,236 1,943 1,943 Residential 96,961 1,572 570 99,939 1,835 1,316 Residential-limited documentation 101,877 1,501 378 116,191 1,539 618 Consumer: Home equity lines and loans 41,740 368 112 21,952 231 66 Automobile 18,571 303 19 24,429 391 39 Other 4,077 72 11 19,238 188 23 Total $ 749,774 6,961 4,235 773,478 9,552 7,430 Nine months ended September 30, 2016 Nine months ended September 30, 2015 Interest income recognized Interest income recognized Average recorded investment Total Cash basis Average recorded investment Total Cash basis (in thousands) Commercial, financial, leasing, etc. $ 283,783 7,055 7,055 226,243 2,123 2,123 Real estate: Commercial 177,579 3,891 3,891 161,834 4,433 4,433 Residential builder and developer 30,832 488 488 64,165 275 275 Other commercial construction 19,774 563 563 22,130 2,166 2,166 Residential 97,229 4,778 2,591 101,997 4,639 3,011 Residential-limited documentation 104,382 4,580 1,648 120,710 4,799 1,962 Consumer: Home equity lines and loans 33,998 937 295 20,619 656 179 Automobile 20,358 964 83 26,521 1,257 136 Other 10,987 371 74 19,053 547 86 Total $ 778,922 23,627 16,688 763,272 20,895 14,371 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 loan review personnel each quarter to determine the appropriateness of the assigned loan grade, including whether the loan should be reported as accruing or nonaccruing. Smaller-balance criticized loans are analyzed by business line risk management areas to ensure proper loan grade classification. Furthermore, criticized nonaccrual commercial loans and commercial real estate loans are considered impaired and, as a result, specific loss allowances on such loans are established within the allowance for credit losses to the extent appropriate in each individual instance. The following table summarizes the loan grades applied to the various classes of the Company’s commercial loans and commercial real estate loans. 4. Loans and leases and the allowance for credit losses, continued Real Estate Commercial, Residential Other Financial, Builder and Commercial Leasing, etc. Commercial Developer Construction (in thousands) September 30, 2016 Pass $ 20,825,301 23,540,787 1,699,263 5,405,719 Criticized accrual 860,461 921,003 157,863 155,813 Criticized nonaccrual 231,401 157,527 20,118 20,669 Total $ 21,917,163 24,619,317 1,877,244 5,582,201 December 31, 2015 Pass $ 19,442,183 22,697,398 1,497,465 3,834,137 Criticized accrual 738,238 655,257 59,779 228,877 Criticized nonaccrual 241,917 179,606 28,429 16,363 Total $ 20,422,338 23,532,261 1,585,673 4,079,377 In determining the allowance for credit losses, residential real estate loans and consumer loans are generally evaluated collectively after considering such factors as payment performance and recent loss experience and trends, which are mainly driven by current collateral values in the market place as well as the amount of loan defaults. Loss rates on such loans are determined by reference to recent charge-off history and are evaluated (and adjusted if deemed appropriate) through consideration of other factors including near-term forecasted loss estimates developed by the Company’s Credit Department. In arriving at such forecasts, the Company considers the current estimated fair value of its collateral based on geographical adjustments for home price depreciation/appreciation and overall borrower repayment performance. With regard to collateral values, the realizability of such values by the Company contemplates repayment of any first lien position prior to recovering amounts on a second lien position. However, residential real estate loans and outstanding balances of home equity loans and lines of credit that are more than 150 days past due are generally evaluated for collectibility on a loan-by-loan basis giving consideration to estimated collateral values. The carrying value of residential real estate loans and home equity loans and lines of credit for which a partial charge-off has been recognized aggregated $47 million and $33 million, respectively, at September 30, 2016 and $55 million and $21 million, respectively, at December 31, 2015. Residential real estate loans and home equity loans and lines of credit that were more than 150 days past due but did not require a partial charge-off because the net realizable value of the collateral exceeded the outstanding customer balance totaled $20 million and $38 million, respectively, at September 30, 2016 and $20 million and $28 million, respectively, at December 31, 2015. The Company also measures additional losses for purchased impaired loans when it is probable that the Company will be unable to collect all cash flows expected at acquisition plus additional cash flows expected to be collected arising from changes in estimates after acquisition. The determination of the allocated portion of the allowance for credit losses is very subjective. Given that inherent subjectivity and potential imprecision involved in determining the allocated portion of the allowance for credit losses, the Company also provides an inherent unallocated portion of the allowance. The unallocated portion of the allowance is intended to recognize probable losses that are not otherwise identifiable and includes management’s subjective determination of amounts necessary to provide for the possible use of imprecise estimates in determining the allocated portion of the allowance. Therefore, the level of the unallocated portion of the allowance is primarily reflective of the inherent imprecision in the various calculations used in determining the allocated portion of the allowance for credit losses. Other factors that could also lead to changes in the unallocated portion include the effects of expansion into new markets for which the Company does not have the same degree of familiarity and experience regarding portfolio performance in changing market conditions, the introduction of new loan and lease product types, and other risks associated with the Company’s loan portfolio that may not be specifically identifiable. 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) September 30, 2016 Individually evaluated for impairment $ 55,020 16,608 9,344 12,298 $ 93,270 Collectively evaluated for impairment 273,164 340,737 48,500 138,193 800,594 Purchased impaired — 2,432 749 846 4,027 Allocated $ 328,184 359,777 58,593 151,337 897,891 Unallocated 78,230 Total $ 976,121 December 31, 2015 Individually evaluated for impairment $ 44,752 19,175 12,727 13,306 $ 89,960 Collectively evaluated for impairment 255,615 307,000 57,624 163,511 783,750 Purchased impaired 37 656 1,887 1,503 4,083 Allocated $ 300,404 326,831 72,238 178,320 877,793 Unallocated 78,199 Total $ 955,992 The recorded investment in loans and leases summarized on the basis of the Company’s impairment methodology was as follows: Commercial, Financial, Real Estate Leasing, etc. Commercial Residential Consumer Total (in thousands) September 30, 2016 Individually evaluated for impairment $ 265,234 211,730 198,022 65,017 $ 740,003 Collectively evaluated for impairment 21,651,134 31,800,749 22,838,125 11,999,490 88,289,498 Purchased impaired 795 66,283 548,273 1,640 616,991 Total $ 21,917,163 32,078,762 23,584,420 12,066,147 $ 89,646,492 December 31, 2015 Individually evaluated for impairment $ 272,227 234,132 207,949 65,365 $ 779,673 Collectively evaluated for impairment 20,148,209 28,863,130 25,398,037 11,532,121 85,941,497 Purchased impaired 1,902 100,049 664,117 2,261 768,329 Total $ 20,422,338 29,197,311 26,270,103 11,599,747 $ 87,489,499 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 tables that follow summarize the Company’s loan modification activities that were considered troubled debt restructurings for the three months ended September 30, 2016 and 2015: Recorded investment Financial effects of modification Three months ended September 30, 2016 Number Pre- modification Post- modification Recorded investment (a) Interest (b) (dollars in thousands) Commercial, financial, leasing, etc. Principal deferral 30 $ 41,652 $ 40,183 $ (1,469 ) $ — Combination of concession types 13 27,834 19,802 (8,032 ) (6 ) Real estate: Commercial Principal deferral 14 12,302 11,644 (658 ) — Combination of concession types 4 2,623 2,614 (9 ) (172 ) Residential Principal deferral 21 4,489 4,714 225 — Combination of concession types 9 1,149 1,214 65 (120 ) Residential-limited documentation Principal deferral 3 435 470 35 — Combination of concession types 3 392 493 101 (123 ) Consumer: Home equity lines and loans Principal deferral 4 251 251 — — Combination of concession types 22 2,301 2,301 — (178 ) Automobile Principal deferral 10 186 186 — — Other Principal deferral 1 26 26 — — Total 134 $ 93,640 $ 83,898 $ (9,742 ) $ (599 ) (a) Financial effects impacting the recorded investment included principal payments or advances, charge-offs and capitalized escrow arrearages. (b) Represents the present value of interest rate concessions discounted at the effective rate of the original loan. 4. Loans and leases and the allowance for credit losses, continued Recorded investment Financial effects of modification Three months ended September 30, 2015 Number Pre- modification Post- modification Recorded investment (a) Interest (b) (dollars in thousands) Commercial, financial, leasing, etc. Principal deferral 36 $ 7,893 $ 7,419 $ (474 ) $ — Combination of concession types 1 31 31 — (6 ) Real estate: Commercial Principal deferral 15 4,230 4,208 (22 ) — Combination of concession types 1 1,156 1,169 13 (54 ) Other commercial construction Principal deferral 3 296 390 94 — Residential Principal deferral 31 3,540 3,743 203 — Other 1 267 267 — — Combination of concession types 10 1,296 1,380 84 (178 ) Residential-limited documentation Principal deferral 1 265 276 11 — Combination of concession types 4 605 662 57 (91 ) Consumer: Home equity lines and loans Principal deferral 4 727 727 — — Combination of concession types 22 2,003 2,003 — (199 ) Automobile Principal deferral 35 316 316 — — Other 15 93 93 — — Combination of concession types 25 471 471 — (17 ) Other Principal deferral 24 352 352 — — Other 5 33 33 — — Combination of concession types 12 117 117 — (12 ) Total 245 $ 23,691 $ 23,657 $ (34 ) $ (557 ) (a) Financial effects impacting the recorded investment included principal payments or advances, charge-offs and capitalized escrow arrearages. (b) Represents the present value of interest rate concessions discounted at the effective rate of the original loan. 4. Loans and leases and the allowance for credit losses, continued The tables below summarize the Company’s loan modification activities that were considered troubled debt restructurings for the nine months ended September 30, 2016 and 2015: Recorded investment Financial effects of modification Nine months ended September 30, 2016 Number Pre- modification Post- modification Recorded investment (a) Interest (b) (dollars in thousands) Commercial, financial, leasing, etc. Principal deferral 87 $ 98,956 $ 98,561 $ (395 ) $ — Combination of concession types 25 49,248 39,971 (9,277 ) (6 ) Real estate: Commercial Principal deferral 40 18,511 17,802 (709 ) — Interest rate reduction 1 129 129 — (25 ) Other 1 4,723 4,447 (276 ) — Combination of concession types 13 13,621 13,546 (75 ) (238 ) Residential builder and developer Principal deferral 3 23,905 22,958 (947 ) — Other commercial construction Principal deferral 1 250 250 — — Combination of concession types 1 124 124 — — Residential Principal deferral 46 7,433 7,945 512 — Combination of concession types 27 4,513 4,705 192 (120 ) Residential-limited documentation Principal deferral 6 711 803 92 — Combination of concession types 8 1,704 1,872 168 (462 ) Consumer: Home equity lines and loans Principal deferral 8 655 655 — — Combination of concession types 76 8,534 8,534 — (741 ) Automobile Principal deferral 102 865 865 — — Other 38 55 55 — — Combination of concession types 8 85 85 — (3 ) Other Principal deferral 56 951 951 — — Other 5 45 45 — — Combination of concession types 17 196 196 — (32 ) Total 569 $ 235,214 $ 224,499 $ (10,715 ) $ (1,627 ) (a) Financial effects impacting the recorded investment included principal payments or advances, charge-offs and capitalized escrow arrearages. (b) Represents the present value of interest rate concessions discounted at the effective rate of the original loan. 4. Loans and leases and the allowance for credit losses, continued Recorded investment Financial effects of modification Nine months ended September 30, 2015 Number Pre- modification Post- modification Recorded investment (a) Interest (b) (dollars in thousands) Commercial, financial, leasing, etc. Principal deferral 87 $ 25,483 $ 24,331 $ (1,152 ) $ — Interest rate reduction 1 99 99 — (19 ) Other 2 8,991 8,883 (108 ) — Combination of concession types 6 25,075 24,884 (191 ) (245 ) Real estate: Commercial Principal deferral 37 47,005 45,569 (1,436 ) — Combination of concession types 6 3,238 3,242 4 (159 ) Residential builder and developer Principal deferral 2 10,650 10,598 (52 ) — Other commercial construction Principal deferral 3 296 390 94 — Residential Principal deferral 50 4,954 5,239 285 — Other 1 267 267 — — Combination of concession types 22 2,551 2,795 244 (356 ) Residential-limited documentation Principal deferral 2 426 437 11 — Combination of concession types 7 1,239 1,298 59 (121 ) Consumer: Home equity lines and loans Principal deferral 6 1,946 1,946 — — Combination of concession types 41 3,555 3,555 — (424 ) Automobile Principal deferral 133 1,234 1,234 — — Interest rate reduction 7 137 137 — (10 ) Other 38 134 134 — — Combination of concession types 42 693 693 — (28 ) Other Principal deferral 73 1,418 1,418 — — Other 12 113 113 — — Combination of concession types 35 384 384 — (44 ) Total 613 $ 139,888 $ 137,646 $ (2,242 ) $ (1,406 ) (a) Financial effects impacting the recorded investment included principal payments or advances, charge-offs and capitalized escrow arrearages. (b) Represents the present value of interest rate concessions discounted at the effective rate of the original loan. Troubled debt restructurings are considered to be impaired loans and for purposes of establishing the allowance for credit losses are evaluated for impairment giving consideration to the impact of the modified loan terms on the present value of the loan’s expected cash flows. Impairment of troubled debt restructurings that have subsequently defaulted may also be measured based on the loan’s observable market price or the fair value of collateral if the loan is collateral-dependent. Charge-offs may also be recognized on troubled debt restructurings that have subsequently defaulted. Loans that were modified as troubled debt restructurings during the twelve months ended September 30, 2016 and 2015 and for which there was a subsequent payment default during the nine-month periods ended September 30, 2016 and 2015, respectively, were not material. 4. Loans and leases and the allowance for credit losses, continued The amount of foreclosed residential real estate property held by the Company was $148 million and $172 million at September 30, 2016 and December 31, 2015, respectively. There were $321 million and $315 million at September 30, 2016 and December 31, 2015, respectively, in loans secured by residential real estate and serviced by the Company that were in the process of foreclosure. There were $246 million at September 30, 2016 in loans secured by residential real estate and serviced by other entities for the Company that were in the process of foreclosure. Of all loans in the process of foreclosure at September 30, 2016, approximately 61% were classified as purchased impaired and 21% were government guaranteed.

Borrowings

Borrowings	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Borrowings	5. Borrowings M&T had $516 million of fixed and variable rate junior subordinated deferrable interest debentures ("Junior Subordinated Debentures") outstanding at September 30, 2016 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, beginning in 2016 none of the securities are includable in M&T’s Tier 1 regulatory capital, but do qualify for inclusion in 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. Also included in long-term borrowings are agreements to repurchase securities of $1.8 billion and $1.9 billion at September 30, 2016 and December 31, 2015, 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 $1.9 billion and $2.0 billion at September 30, 2016 and December 31, 2015, respectively.

Shareholders' equity

Shareholders' equity	9 Months Ended
	Sep. 30, 2016
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 September 30, 2016 and December 31, 2015 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 D (b) Fixed Rate Non-cumulative Perpetual Preferred Stock, $10,000 liquidation preference per share 50,000 $ 500,000 Series E (c) Fixed-to-Floating Rate Non-cumulative Perpetual Preferred Stock, $1,000 liquidation preference per share 350,000 $ 350,000 (a) Dividends, if declared, are paid at 6.375%. Warrants to purchase M&T common stock at $73.86 per share issued in connection with the Series A preferred stock expire in 2018 and totaled 713,855 at September 30, 2016 and 719,175 at December 31, 2015. (b) Dividends, if declared, are paid semi-annually at a rate of 6.875% per year. The shares became redeemable in whole or in part on June 15, 2016. (c) Dividends, if declared, are paid semi-annually at a rate of 6.45% through February 14, 2024 and thereafter will be paid quarterly at a rate of the three-month LIBOR plus 361 basis points (hundredths of one percent). The shares are redeemable in whole or in part on or after February 15, 2024. Notwithstanding M&T’s option to redeem the shares, if an event occurs such that the shares no longer qualify as Tier 1 capital, M&T may redeem all of the shares within 90 days following that occurrence. In addition to the Series A warrants mentioned in (a) above, a warrant to purchase 95,383 shares of M&T common stock at $518.96 per share was outstanding at September 30, 2016 and December 31, 2015. The obligation under that warrant was assumed by M&T in an acquisition. On October 28, 2016, M&T issued 50,000 shares of Series F Perpetual Fixed-to-Floating Rate Non-cumulative Preferred Stock, par value $1.00 per share and liquidation preference of $10,000 per share. Through November 1, 2026 holders of the Series F preferred stock are entitled to receive, only when, as and if declared by M&T’s Board of Directors, non-cumulative cash dividends at an annual rate of 5.125%, payable semi-annually in arrears. Subsequent to November 1, 2026 holders will be entitled to receive quarterly cash dividends at an annual rate of three-month LIBOR plus 352 basis points. The Series F preferred stock may be redeemed at M&T’s option, in whole or in part, on any dividend payment date on or after November 1, 2026 or, in whole but not in part, at any time within 90 days following a regulatory capital treatment event whereby the full liquidation value of the shares no longer qualifies as “additional Tier 1 capital”. In addition, M&T expects to redeem the 50,000 shares issued and outstanding of the Series D Fixed Rate Non-cumulative Perpetual Preferred Stock, $10,000 liquidation preference per share during December 2016, having received the approval of the Federal Reserve to redeem such shares after issuing the Series F preferred stock.

Pension plans and other postret

Pension plans and other postretirement benefits	9 Months Ended
	Sep. 30, 2016
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 September 30 2016 2015 2016 2015 (in thousands) Service cost $ 6,259 5,916 399 188 Interest cost on projected benefit obligation 20,853 17,754 1,242 651 Expected return on plan assets (27,118 ) (23,527 ) — — Amortization of prior service credit (807 ) (1,501 ) (339 ) (340 ) Amortization of net actuarial loss 7,536 11,207 15 26 Net periodic benefit cost $ 6,723 9,849 1,317 525 Pension benefits Other postretirement benefits Nine months ended September 30 2016 2015 2016 2015 (in thousands) Service cost $ 18,778 17,748 1,197 562 Interest cost on projected benefit obligation 62,558 53,261 3,728 1,953 Expected return on plan assets (81,355 ) (70,578 ) — — Amortization of prior service credit (2,421 ) (4,504 ) (1,019 ) (1,019 ) Amortization of net actuarial loss 22,609 33,619 45 79 Net periodic benefit cost $ 20,169 29,546 3,951 1,575 Expense incurred in connection with the Company's defined contribution pension and retirement savings plans totaled $14,783,000 and $14,281,000 for the three months ended September 30, 2016 and 2015, respectively, and $47,747,000 and $44,377,000 for the nine months ended September 30, 2016 and 2015, respectively.

Earnings per common share

Earnings per common share	9 Months Ended
	Sep. 30, 2016
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 September 30 Nine months ended September 30 2016 2015 2016 2015 (in thousands, except per share) Income available to common shareholders: Net income $ 349,984 280,401 984,543 808,702 Less: Preferred stock dividends (a) (20,318 ) (20,318 ) (60,953 ) (60,953 ) Net income available to common equity 329,666 260,083 923,590 747,749 Less: Income attributable to unvested stock-based compensation awards (2,674 ) (2,746 ) (7,920 ) (8,122 ) Net income available to common shareholders $ 326,992 257,337 915,670 739,627 Weighted-average shares outstanding: Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards 156,767 134,049 158,710 133,805 Less: Unvested stock-based compensation awards (1,274 ) (1,419 ) (1,374 ) (1,458 ) Weighted-average shares outstanding 155,493 132,630 157,336 132,347 Basic earnings per common share $ 2.10 1.94 5.82 5.59 (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 September 30 Nine months ended September 30 2016 2015 2016 2015 (in thousands, except per share) Net income available to common equity $ 329,666 260,083 923,590 747,749 Less: Income attributable to unvested stock-based compensation awards (2,668 ) (2,737 ) (7,904 ) (8,093 ) Net income available to common shareholders $ 326,998 257,346 915,686 739,656 Adjusted weighted-average shares outstanding: Common and unvested stock-based compensation awards 156,767 134,049 158,710 133,805 Less: Unvested stock-based compensation awards (1,274 ) (1,419 ) (1,374 ) (1,458 ) Plus: Incremental shares from assumed conversion of stock-based compensation awards and warrants to purchase common stock 533 746 507 742 Adjusted weighted-average shares outstanding 156,026 133,376 157,843 133,089 Diluted earnings per common share $ 2.10 1.93 5.80 5.56 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 approximately 2.0 million and 1.5 million common shares during the three-month periods ended September 30, 2016 and 2015, respectively, and 2.5 million and 1.9 million common shares during the nine-month periods ended September 30, 2016 and 2015, 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	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Comprehensive income	9. Comprehensive income The following tables displays 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, 2016 $ 16,359 62,849 (489,660 ) (4,093 ) $ (414,545 ) 162,918 $ (251,627 ) Other comprehensive income before reclassifications: Unrealized holding gains, net 1,228 234,438 — — 235,666 (92,714 ) 142,952 Foreign currency translation adjustment — — — (2,836 ) (2,836 ) 989 (1,847 ) Total other comprehensive income (loss) before reclassifications 1,228 234,438 — (2,836 ) 232,830 (91,725 ) 141,105 Amounts reclassified from accumulated other comprehensive income that (increase) decrease net income: Accretion of unrealized holding losses on held-to-maturity (“HTM”) securities — 2,998 — — 2,998 (b) (1,180 ) 1,818 Gains realized in net income — (28,748 ) — — (28,748 ) (c) 11,309 (17,439 ) Accretion of net gain on terminated cash flow hedges — — — (116 ) (116 ) (d) 46 (70 ) Amortization of prior service credit — — (3,440 ) — (3,440 ) (e) 1,354 (2,086 ) Amortization of actuarial losses — — 22,654 — 22,654 (e) (8,914 ) 13,740 Total reclassifications — (25,750 ) 19,214 (116 ) (6,652 ) 2,615 (4,037 ) Total gain (loss) during the period 1,228 208,688 19,214 (2,952 ) 226,178 (89,110 ) 137,068 Balance - September 30, 2016 $ 17,587 271,537 (470,446 ) (7,045 ) $ (188,367 ) 73,808 $ (114,559 ) Balance - January 1, 2015 $ 7,438 201,828 (503,027 ) (4,082 ) $ (297,843 ) 116,849 $ (180,994 ) Other comprehensive income before reclassifications: Unrealized holding gains (losses), net 9,699 (11,139 ) — — (1,440 ) 952 (488 ) Foreign currency translation adjustment — — — (735 ) (735 ) 214 (521 ) Gains on cash flow hedges — — — 1,453 1,453 (568 ) 885 Total other comprehensive income before reclassifications 9,699 (11,139 ) — 718 (722 ) 598 (124 ) Amounts reclassified from accumulated other comprehensive income that (increase) decrease net income: Accretion of unrealized holding losses on HTM securities — 2,417 — — 2,417 (b) (944 ) 1,473 Losses realized in net income — 108 — — 108 (c) (40 ) 68 Accretion of net gain on terminated cash flow hedges — — — (102 ) (102 ) (d) 40 (62 ) Amortization of prior service credit — — (5,523 ) — (5,523 ) (e) 2,359 (3,164 ) Amortization of actuarial losses — — 33,698 — 33,698 (e) (14,368 ) 19,330 Total reclassifications — 2,525 28,175 (102 ) 30,598 (12,953 ) 17,645 Total gain (loss) during the period 9,699 (8,614 ) 28,175 616 29,876 (12,355 ) 17,521 Balance - September 30, 2015 $ 17,137 193,214 (474,852 ) (3,466 ) $ (267,967 ) 104,494 $ (163,473 ) (a) Other-than-temporary impairment (b) Included in interest income (c) Included in gain (loss) on bank investment securities (d) Included in interest expense (e) Included in salaries and employee benefits expense Accumulated other comprehensive income (loss), net consisted of the following: Investment securities Defined benefit With OTTI All other plans Other Total (in thousands) Balance - December 31, 2015 $ 9,921 38,166 (296,979 ) (2,735 ) $ (251,627 ) Net gain (loss) during period 745 126,586 11,654 (1,917 ) 137,068 Balance - September 30, 2016 $ 10,666 164,752 (285,325 ) (4,652 ) $ (114,559 )

Derivative financial instrument

Derivative financial instruments	9 Months Ended
	Sep. 30, 2016
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 and collateral provisions protecting the at-risk party. Based on adherence to the Company’s credit standards and the presence of the netting and collateral provisions, the Company believes that the credit risk inherent in these contracts was not material as of September 30, 2016. The net effect of interest rate swap agreements was to increase net interest income by $9 million and $11 million for the three-month periods ended September 30, 2016 and 2015, respectively, and $30 million and $33 million for the nine-month periods ended September 30, 2016 and 2015, 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 amount maturity Fixed Variable (in thousands) (in years) September 30, 2016 Fair value hedges: Fixed rate long-term borrowings (a) $ 1,400,000 0.9 4.42 % 1.79 % December 31, 2015 Fair value hedges: Fixed rate long-term borrowings (a) $ 1,400,000 1.7 4.42 % 1.39 % (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 $21.2 billion and $18.4 billion at September 30, 2016 and December 31, 2015, respectively. The notional amounts of foreign currency and other option and futures contracts entered into for trading account purposes aggregated $891 million and $1.6 billion at September 30, 2016 and December 31, 2015, 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 September 30, 2016 December 31, 2015 September 30, 2016 December 31, 2015 (in thousands) Derivatives designated and qualifying as hedging instruments Fair value hedges: Interest rate swap agreements (a) $ 21,060 43,892 $ — — Commitments to sell real estate loans (a) 382 1,844 3,946 656 21,442 45,736 3,946 656 Derivatives not designated and qualifying as hedging instruments Mortgage-related commitments to originate real estate loans for sale (a) 29,851 10,282 51 403 Commitments to sell real estate loans (a) 626 533 8,437 846 Trading: Interest rate contracts (b) 346,453 203,517 286,298 153,723 Foreign exchange and other option and futures contracts (b) 7,092 8,569 6,415 7,022 384,022 222,901 301,201 161,994 Total derivatives $ 405,464 268,637 $ 305,147 162,650 (a) Asset derivatives are reported in other assets and liability derivatives are reported in other liabilities. (b) Asset derivatives are reported in trading account assets and liability derivatives are reported in other liabilities. Amount of gain (loss) recognized Three months ended September 30, 2016 Three months ended September 30, 2015 Derivative Hedged item Derivative Hedged item (in thousands) Derivatives in fair value hedging relationships Interest rate swap agreements: Fixed rate long-term borrowings (a) $ (12,588 ) 12,587 $ (2,719 ) 2,382 Derivatives not designated as hedging instruments Trading: Interest rate contracts (b) $ 4,822 $ 4,120 Foreign exchange and other option and futures contracts (b) 1,746 2,613 Total $ 6,568 $ 6,733 10. Derivative financial instruments, continued Amount of gain (loss) recognized Nine months ended September 30, 2016 Nine months ended September 30, 2015 Derivative Hedged item Derivative Hedged item (in thousands) Derivatives in fair value hedging relationships Interest rate swap agreements: Fixed rate long-term borrowings (a) $ (22,832 ) 21,603 $ (12,469 ) 11,495 Derivatives not designated as hedging instruments Trading: Interest rate contracts (b) $ 11,578 $ 6,552 Foreign exchange and other option and futures contracts (b) 5,415 7,023 Total $ 16,993 $ 13,575 (a) Reported as other revenues from operations. (b) Reported as trading account and foreign exchange gains. The Company 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 $38 million and $18 million at September 30, 2016 and December 31, 2015, respectively. Changes in unrealized gains and losses are included in mortgage banking revenues and, in general, are realized in subsequent periods as the related loans are sold and commitments satisfied. The Company does not offset derivative asset and liability positions in its consolidated financial statements. The Company’s exposure to credit risk by entering into derivative contracts is mitigated through master netting agreements and collateral posting requirements. Master netting agreements covering interest rate and foreign exchange contracts with the same party include a right to set-off that becomes enforceable in the event of default, early termination or under other specific conditions. The aggregate fair value of derivative financial instruments in a liability position, which are subject to enforceable master netting arrangements, was $85 million and $59 million at September 30, 2016 and December 31, 2015, respectively. After consideration of such netting arrangements, the net liability positions with counterparties aggregated $81 million and $55 million at September 30, 2016 and December 31, 2015, respectively. The Company was required to post collateral relating to those positions of $79 million and $52 million at September 30, 2016 and December 31, 2015, respectively. Certain of the Company’s derivative financial instruments contain provisions that require the Company to maintain specific credit ratings from credit rating agencies to avoid higher collateral posting requirements. If the Company’s debt 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 September 30, 2016 was $19 million, for which the Company had posted collateral of $15 million in the normal course of business. If the credit risk-related contingent features had been triggered on September 30, 2016, the maximum amount of additional collateral the Company would have been required to post to counterparties was $4 million. The aggregate fair value of derivative financial instruments in an asset position, which are subject to enforceable master netting arrangements, was $15 million and $23 million at September 30, 2016 and December 31, 2015, respectively. After consideration of such netting arrangements, the net asset positions with counterparties aggregated $11 million and $19 million at September 30, 2016 and December 31, 2015, respectively. Counterparties posted collateral relating to those positions of $11 million and $22 million at September 30, 2016 and December 31, 2015, respectively. Trading account interest rate swap agreements entered into with customers are subject to the Company’s credit risk standards and often contain collateral provisions. In addition to the derivative contracts noted above, the Company clears certain derivative transactions through a clearinghouse, rather than directly with counterparties. Those transactions cleared through a clearinghouse require initial margin collateral and additional collateral for contracts in a net liability position. The net fair values of derivative financial instruments cleared through clearinghouses at September 30, 2016 was a net liability position of $177 million and at December 31, 2015 was a net liability position of $50 million. Collateral posted with clearinghouses was $265 million and $99 million at September 30, 2016 and December 31, 2015, respectively.

Variable interest entities and

Variable interest entities and asset securitizations	9 Months Ended
	Sep. 30, 2016
Text Block [Abstract]
Variable interest entities and asset securitizations	11. Variable interest entities and asset securitizations In accordance with GAAP, at December 31, 2015 the Company determined that it was the primary beneficiary of a residential mortgage loan securitization trust considering its role as servicer and its retained subordinated interests in the trust. As a result, the Company had included the one-to-four family residential mortgage loans that were included in the trust in its consolidated financial statements. In the first quarter of 2016, the securitization trust was terminated as the Company exercised its right to purchase the underlying mortgage loans pursuant to the clean-up call provisions of the trust. At December 31, 2015, the carrying values of the loans in the securitization trust was $81 million. The outstanding principal amount of mortgage-backed securities issued by the qualified special purpose trust that was held by parties unrelated to the Company at December 31, 2015 was $13 million. 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 September 30, 2016 and December 31, 2015, the Company included the junior subordinated debentures as “long-term borrowings” in its consolidated balance sheet and recognized $24 million in other assets for its “investment” in the common securities of the trusts that will be concomitantly repaid to M&T by the respective trust from the proceeds of M&T’s repayment of the junior subordinated debentures associated with preferred capital securities described in note 5. The Company has invested as a limited partner in various partnerships that collectively had total assets of approximately $1.1 billion at each of September 30, 2016 and December 31, 2015. Those partnerships generally construct or acquire properties for which the investing partners are eligible to receive certain federal income tax credits in accordance with government guidelines. Such investments may also provide tax deductible losses to the partners. The partnership investments also assist the Company in achieving its community reinvestment initiatives. As a limited partner, there is no recourse to the Company by creditors of the partnerships. However, the tax credits that result from the Company’s investments in such partnerships are generally subject to recapture should a partnership fail to comply with the respective government regulations. The Company’s maximum exposure to loss of its investments in such partnerships was $287 million, including $82 million of unfunded commitments, at September 30, 2016 and $295 million, including $78 million of unfunded commitments, at December 31, 2015. Contingent commitments to provide additional capital contributions to these partnerships were not material at September 30, 2016. The Company has not provided financial or other support to the partnerships that was not contractually required. Management currently estimates that no material losses are probable as a result of the Company’s involvement with such entities. The Company, in its position as limited partner, does not direct the activities that most significantly impact the economic performance of the partnerships and, therefore, in accordance with the accounting provisions for variable interest entities, the partnership entities are not included in the Company’s consolidated financial statements. The Company’s investment cost is amortized to income taxes in the consolidated statement of income as tax credits and other tax benefits resulting from deductible losses associated with the projects are received. The Company amortized $13 million and $34 million of its investments in qualified affordable housing projects to income tax expense during the three months and nine months ended September 30, 2016, respectively, and recognized $18 million and $46 million of tax credits and other tax benefits during those respective periods. Similarly, for the three months and nine months ended September 30, 2015, the Company amortized $10 million and $31 million, respectively, of its investments in qualified affordable housing projects to income tax expense, and recognized $15 million and $44 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	9 Months Ended
	Sep. 30, 2016
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 September 30, 2016. Pursuant to GAAP, fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. A three-level hierarchy exists in GAAP for fair value measurements based upon the inputs to the valuation of an asset or liability. • Level 1 — Valuation is based on quoted prices in active markets for identical assets and liabilities. • Level 2 — Valuation is determined from quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar instruments in markets that are not active or by model-based techniques in which all significant inputs are observable in the market. 12. Fair value measurements, continued • Level 3 — Valuation is derived from model-based and other techniques in which at least one significant input is unobservable and which may be based on the Company's own estimates about the assumptions that market participants would use to value the asset or liability. When available, the Company attempts to use quoted market prices in active markets to determine fair value and classifies such items as Level 1 or Level 2. If quoted market prices in active markets are not available, fair value is often determined using model-based techniques incorporating various assumptions including interest rates, prepayment speeds and credit losses. Assets and liabilities valued using model-based techniques are classified as either Level 2 or Level 3, depending on the lowest level classification of an input that is considered significant to the overall valuation. The following is a description of the valuation methodologies used for the Company's assets and liabilities that are measured on a recurring basis at estimated fair value. Trading account assets and liabilities Trading account assets and liabilities consist primarily of interest rate swap agreements and foreign exchange contracts with customers who require such services with offsetting positions with third parties to minimize the Company's risk with respect to such transactions. The Company generally determines the fair value of its derivative trading account assets and liabilities using externally developed pricing models based on market observable inputs and, therefore, classifies such valuations as Level 2. Mutual funds held in connection with deferred compensation and other arrangements have been classified as Level 1 valuations. Valuations of investments in municipal and other bonds can generally be obtained through reference to quoted prices in less active markets for the same or similar securities or through model-based techniques in which all significant inputs are observable and, therefore, such valuations have been classified as Level 2. Investment securities available for sale The majority of the Company's available-for-sale investment securities have been valued by reference to prices for similar securities or through model-based techniques in which all significant inputs are observable and, therefore, such valuations have been classified as Level 2. Certain investments in mutual funds and equity securities are actively traded and, therefore, have been classified as Level 1 valuations. Included in collateralized debt obligations at December 31, 2015 were securities backed by trust preferred securities issued by financial institutions and other entities. As disclosed in Note 3, in the third quarter of 2016 the Company sold substantially all of its collateralized debt obligations. The Company performed internal modeling to estimate the cash flows and fair value of its portfolio of securities backed by trust preferred securities at December 31, 2015. The modeling techniques included estimating cash flows using bond-specific assumptions about future collateral defaults and related loss severities. The resulting cash flows were then discounted by reference to market yields observed in the single-name trust preferred securities market. In determining a market yield applicable to the estimated cash flows, a margin over LIBOR ranging from 4% to 10%, with a weighted-average of 8%, was used. Significant unobservable inputs used in the determination of estimated fair value of collateralized debt obligations are included in the accompanying table of significant unobservable inputs to Level 3 measurements. At December 31, 2015, the total amortized cost and fair value of securities backed by trust preferred securities issued by financial institutions and other entities were $28 million and $47 million, respectively. Privately issued mortgage-backed securities and securities backed by trust preferred securities issued by financial institutions and other entities constituted all of the available-for-sale investment securities classified as Level 3 valuations. 12. Fair value measurements, continued The Company ensures an appropriate control framework is in place over the valuation processes and techniques used for significant Level 3 fair value measurements. Internal pricing models used for significant valuation measurements have generally been subjected to validation procedures including testing of mathematical constructs, review of valuation methodology and significant assumptions used. 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 September 30, 2016 and December 31, 2015 measured at estimated fair value on a recurring basis: Fair value measurements at September 30, 2016 Level 1 (a) Level 2 (a) Level 3 (in thousands) Trading account assets $ 488,588 50,699 437,889 — Investment securities available for sale: U.S. Treasury and federal agencies 726,401 — 726,401 — Obligations of states and political subdivisions 5,015 — 5,015 — Mortgage-backed securities: Government issued or guaranteed 10,930,662 — 10,930,662 — Privately issued 51 — — 51 Other debt securities 118,226 — 118,226 — Equity securities 82,212 62,546 19,666 — 11,862,567 62,546 11,799,970 51 Real estate loans held for sale 704,984 — 704,984 — Other assets (b) 51,919 — 22,068 29,851 Total assets $ 13,108,058 113,245 12,964,911 29,902 Trading account liabilities $ 292,713 — 292,713 — Other liabilities (b) 12,434 — 12,383 51 Total liabilities $ 305,147 — 305,096 51 Fair value measurements at December 31, 2015 Level 1(a) Level 2(a) Level 3 (in thousands) Trading account assets $ 273,783 56,763 217,020 — Investment securities available for sale: U.S. Treasury and federal agencies 299,997 — 299,997 — Obligations of states and political subdivisions 6,028 — 6,028 — Mortgage-backed securities: Government issued or guaranteed 11,686,628 — 11,686,628 — Privately issued 74 — — 74 Collateralized debt obligations 47,393 — — 47,393 Other debt securities 118,880 — 118,880 — Equity securities 83,671 65,178 18,493 — 12,242,671 65,178 12,130,026 47,467 Real estate loans held for sale 392,036 — 392,036 — Other assets (b) 56,551 — 46,269 10,282 Total assets $ 12,965,041 121,941 12,785,351 57,749 Trading account liabilities $ 160,745 — 160,745 — Other liabilities (b) 1,905 — 1,502 403 Total liabilities $ 162,650 — 162,247 403 (a) There were no significant transfers between Level 1 and Level 2 of the fair value hierarchy during the nine months ended September 30, 2016 and the year ended December 31, 2015. (b) Comprised predominantly of interest rate swap agreements used for interest rate risk management (Level 2), commitments to sell real estate loans (Level 2) and commitments to originate real estate loans to be held for sale (Level 3). 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 September 30, 2016 were as follows: Investment securities available for Privately issued mortgage-backed securities Collateralized debt obligations Other assets and other liabilities (in thousands) Balance - June 30, 2016 $ 57 43,305 21,383 Total gains (losses) realized/unrealized: Included in earnings — 28,475 45,534 (b) Included in other comprehensive income — (15,050 ) (c) — Sales — (56,730 ) — Settlements (6 ) — — Transfers in and/or out of Level 3 (a) — — (37,117 ) (d) Balance - September 30, 2016 $ 51 — 29,800 Changes in unrealized gains included in earnings related to assets still held at September 30, 2016 $ — — 27,663 (b) The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the three months ended September 30, 2015 were as follows: Investment securities available for sale Privately issued mortgage-backed securities Collateralized debt obligations Other assets and other liabilities (in thousands) Balance - June 30, 2015 $ 88 50,483 11,206 Total gains (losses) realized/unrealized: Included in earnings — — 21,709 (b) Included in other comprehensive income — (472 ) (c) — Settlements (6 ) (135 ) — Transfers in and/or out of Level 3 (a) — — (15,268 ) (d) Balance - September 30, 2015 $ 82 49,876 17,647 Changes in unrealized gains included in earnings related to assets still held at September 30, 2015 $ — — 15,488 (b) 12. Fair value measurements, continued The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the nine months ended September 30, 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 — 28,475 104,862 (b) Included in other comprehensive income — (18,268 ) (c) — Sales — (56,730 ) — Settlements (23 ) (870 ) — Transfers in and/or out of Level 3 (a) — — (84,941 ) (d) Balance – September 30, 2016 $ 51 — 29,800 Changes in unrealized gains included in earnings related to assets still held at September 30, 2016 $ — — 29,288 (b) The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the nine months ended September 30, 2015 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, 2015 $ 103 50,316 17,347 Total gains (losses) realized/unrealized: Included in earnings — — 67,611 (b) Included in other comprehensive income — 5,153 (c) — Settlements (21 ) (5,593 ) — Transfers in and/or out of Level 3 (a) — — (67,311 ) (d) Balance - September 30, 2015 $ 82 49,876 17,647 Changes in unrealized gains included in earnings related to assets still held at September 30, 2015 $ — — 15,965 (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 gains (losses) on investment securities in the consolidated statement of comprehensive income. (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 92% at September 30, 2016. As these discounts are not readily observable and are considered significant, the valuations have been classified as Level 3. Automobile collateral is typically valued by reference to independent pricing sources based on recent sales transactions of similar vehicles, and the related non-recurring fair value measurement adjustments have been classified as Level 2. Collateral values for other consumer installment loans are generally estimated based on historical recovery rates for similar types of loans. As these recovery rates are not readily observable by market participants, such valuation adjustments have been classified as Level 3. Loans subject to nonrecurring fair value measurement were $249 million at September 30, 2016 ($144 million and $105 million of which were classified as Level 2 and Level 3, respectively), $210 million at December 31, 2015 ($106 million and $104 million of which were classified as Level 2 and Level 3, respectively) and $177 million at September 30, 2015 ($106 million and $71 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 September 30, 2016 were decreases of $20 million and $42 million for the three-month and nine-month periods ended September 30, 2016, respectively. Changes in fair value recognized for partial charge-offs of loans and loan impairment reserves on loans held by the Company on September 30, 2015 were decreases of $11 million and $53 million for the three-month and nine-month periods ended September 30, 2015, 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 $53 million and $15 million at September 30, 2016 and September 30, 2015, respectively. Changes in fair value recognized for those foreclosed assets held by the Company were not material during the three-month and nine-month periods ended September 30, 2016 and 2015. 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 September 30, 2016 and December 31, 2015: Fair value at September 30, 2016 Valuation technique Unobservable input/assumptions Range (weighted- average) (in thousands) Recurring fair value measurements Privately issued mortgage-backed securities $ 51 Two independent pricing quotes — — Net other assets (liabilities) (a) 29,800 Discounted cash flow Commitment expirations 0%-92% (26%) Fair value at December 31, 2015 Valuation technique Unobservable input/assumptions Range (weighted- average) (in thousands) Recurring fair value measurements Privately issued mortgage-backed securities $ 74 Two independent pricing quotes — — Collateralized debt obligations 47,393 Discounted cash flow Probability of default 10%-56% (31%) Loss severity 100% Net other assets (liabilities) (a) 9,879 Discounted cash flow Commitment expirations 0%-60% (39%) (a) Other Level 3 assets (liabilities) consist of commitments to originate real estate loans. Sensitivity of fair value measurements to changes in unobservable inputs An increase (decrease) in the probability of default and loss severity for collateralized debt securities would generally result in a lower (higher) fair value measurement. 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: September 30, 2016 Carrying amount Estimated fair value Level 1 Level 2 Level 3 (in thousands) Financial assets: Cash and cash equivalents $ 1,332,202 1,332,202 1,258,882 73,320 — Interest-bearing deposits at banks 10,777,636 10,777,636 — 10,777,636 — Trading account assets 488,588 488,588 50,699 437,889 — Investment securities 14,733,574 14,779,721 62,546 14,591,141 126,034 Loans and leases: Commercial loans and leases 21,917,163 21,563,190 — — 21,563,190 Commercial real estate loans 32,078,762 31,944,341 — 290,347 31,653,994 Residential real estate loans 23,584,420 23,780,993 — 4,607,044 19,173,949 Consumer loans 12,066,147 12,009,873 — — 12,009,873 Allowance for credit losses (976,121 ) — — — — Loans and leases, net 88,670,371 89,298,397 — 4,897,391 84,401,006 Accrued interest receivable 311,414 311,414 — 311,414 — Financial liabilities: Noninterest-bearing deposits $ (33,127,627 ) (33,127,627 ) — (33,127,627 ) — Savings and interest-checking deposits (53,065,030 ) (53,065,030 ) — (53,065,030 ) — Time deposits (11,721,005 ) (11,829,119 ) — (11,829,119 ) — Deposits at Cayman Islands office (223,183 ) (223,183 ) — (223,183 ) — Short-term borrowings (213,846 ) (213,846 ) — (213,846 ) — Long-term borrowings (10,211,160 ) (10,277,155 ) — (10,277,155 ) — Accrued interest payable (76,230 ) (76,230 ) — (76,230 ) — Trading account liabilities (292,713 ) (292,713 ) — (292,713 ) — Other financial instruments: Commitments to originate real estate loans for sale $ 29,800 29,800 — — 29,800 Commitments to sell real estate loans (11,375 ) (11,375 ) — (11,375 ) — Other credit-related commitments (124,499 ) (124,499 ) — — (124,499 ) Interest rate swap agreements used for interest rate risk management 21,060 21,060 — 21,060 — 12. Fair value measurements, continued December 31, 2015 Carrying amount Estimated fair value Level 1 Level 2 Level 3 (in thousands) Financial assets: Cash and cash equivalents $ 1,368,040 1,368,040 1,276,678 91,362 — Interest-bearing deposits at banks 7,594,350 7,594,350 — 7,594,350 — Trading account assets 273,783 273,783 56,763 217,020 — Investment securities 15,656,439 15,660,877 65,178 15,406,404 189,295 Loans and leases: Commercial loans and leases 20,422,338 20,146,201 — — 20,146,201 Commercial real estate loans 29,197,311 29,044,244 — 38,774 29,005,470 Residential real estate loans 26,270,103 26,267,771 — 4,727,816 21,539,955 Consumer loans 11,599,747 11,550,270 — — 11,550,270 Allowance for credit losses (955,992 ) — — — — Loans and leases, net 86,533,507 87,008,486 — 4,766,590 82,241,896 Accrued interest receivable 306,496 306,496 — 306,496 — Financial liabilities: Noninterest-bearing deposits $ (29,110,635 ) (29,110,635 ) — (29,110,635 ) — Savings and interest-checking deposits (49,566,644 ) (49,566,644 ) — (49,566,644 ) — Time deposits (13,110,392 ) (13,135,042 ) — (13,135,042 ) — Deposits at Cayman Islands office (170,170 ) (170,170 ) — (170,170 ) — Short-term borrowings (2,132,182 ) (2,132,182 ) — (2,132,182 ) — Long-term borrowings (10,653,858 ) (10,639,556 ) — (10,639,556 ) — Accrued interest payable (85,145 ) (85,145 ) — (85,145 ) — Trading account liabilities (160,745 ) (160,745 ) — (160,745 ) — Other financial instruments: Commitments to originate real estate loans for sale $ 9,879 9,879 — — 9,879 Commitments to sell real estate loans 875 875 — 875 — Other credit-related commitments (122,334 ) (122,334 ) — — (122,334 ) Interest rate swap agreements used for interest rate risk management 43,892 43,892 — 43,892 — With the exception of marketable securities, certain off-balance sheet financial instruments and one-to-four family residential 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. 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	9 Months Ended
	Sep. 30, 2016
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. September 30, December 31, 2016 2015 (in thousands) Commitments to extend credit Home equity lines of credit $ 5,525,814 5,631,680 Commercial real estate loans to be sold 403,411 57,597 Other commercial real estate 6,365,999 5,949,933 Residential real estate loans to be sold 635,661 488,621 Other residential real estate 297,191 212,619 Commercial and other 12,219,005 11,802,850 Standby letters of credit 3,283,270 3,330,013 Commercial letters of credit 50,109 55,559 Financial guarantees and indemnification contracts 3,147,784 2,794,322 Commitments to sell real estate loans 1,538,900 782,885 Commitments to extend credit are agreements to lend to customers, generally having fixed expiration dates or other termination clauses that may require payment of a fee. Standby and commercial letters of credit are conditional commitments issued to guarantee the performance of a customer to a third party. Standby letters of credit generally are contingent upon the failure of the customer to perform according to the terms of the underlying contract with the third party, whereas commercial letters of credit are issued to facilitate commerce and typically result in the commitment being funded when the underlying transaction is consummated between the customer and a third party. The credit risk associated with commitments to extend credit and standby and commercial letters of credit is essentially the same as that involved with extending loans to customers and is subject to normal credit policies. Collateral may be obtained based on management's assessment of the customer's creditworthiness. Financial guarantees and indemnification contracts are oftentimes similar to standby letters of credit and include mandatory purchase agreements issued to ensure that customer obligations are fulfilled, recourse obligations associated with sold loans, and other guarantees of customer performance or compliance with designated rules and regulations. Included in financial guarantees and indemnification contracts are loan principal amounts sold with recourse in conjunction with the Company's involvement in the Fannie Mae Delegated Underwriting and Servicing program. The Company's maximum credit risk for recourse associated with loans sold under that program totaled approximately $2.7 billion and $2.5 billion at September 30, 2016 and December 31, 2015, respectively. Since many loan commitments, standby letters of credit, and guarantees and indemnification contracts expire without being funded in whole or in part, the contract amounts are not necessarily indicative of future cash flows. The Company utilizes commitments to sell real estate loans to hedge exposure to changes in the fair value of real estate loans held for sale. Such commitments are considered derivatives and along with commitments to originate real estate loans to be held for sale are generally recorded in the consolidated balance sheet at estimated fair market value. The Company 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. Nevertheless, given the outcome of the matter discussed in the following paragraph, at September 30, 2016 the Company’s remaining obligation to loan purchasers was not considered material to the Company’s consolidated financial position. 13. Commitments and contingencies, continued The Company was the subject of an investigation by government agencies relating to the origination of Federal Housing Administration (“FHA”) insured residential home loans and residential home loans sold to Freddie Mac and Fannie Mae. A number of other U.S. financial institutions have announced similar investigations. Regarding FHA loans, the U.S. Department of Housing and Urban Development (“HUD”) Office of Inspector General and the U.S. Department of Justice (collectively, the “Government”) investigated whether the Company complied with underwriting guidelines concerning certain loans where HUD paid FHA insurance claims. The Company fully cooperated with the investigation. The Government advised the Company that based upon its review of a sample of loans for which an FHA insurance claim was paid by HUD, some of the loans did not meet underwriting guidelines. The Company, based on its own review of the sample, did not agree with the sampling methodology and loan analysis employed by the Government. Regarding loans originated by the Company and sold to Freddie Mac and Fannie Mae, the investigation concerned whether the mortgages sold to Freddie Mac and Fannie Mae complied with applicable underwriting guidelines. The Company also cooperated with that portion of the investigation. In order to bring those investigations to a close, M&T Bank entered into a settlement agreement with the Government under which M&T Bank paid $64 million on May 12, 2016, without admitting liability. As a result, on May 20, 2016, a Joint Stipulation of Dismissal was filed with the United States District Court for the Western District of New York. The settlement did not have a material impact on the Company’s consolidated financial condition or results of operations in the three-month or nine-month periods ended September 30, 2016. M&T and its subsidiaries are subject in the normal course of business to various pending and threatened legal proceedings and other matters in which claims for monetary damages are asserted. On an on-going basis management, after consultation with legal counsel, assesses the Company’s liabilities and contingencies in connection with such proceedings. For those matters where it is probable that the Company will incur losses and the amounts of the losses can be reasonably estimated, the Company records an expense and corresponding liability in its consolidated financial statements. To the extent the pending or threatened litigation could result in exposure in excess of that liability, the amount of such excess is not currently estimable. Although not considered probable, the range of reasonably possible losses for such matters in the aggregate, beyond the existing recorded liability, was between $0 and $40 million. Although the Company does not believe that the outcome of pending litigations will be material to the Company’s consolidated financial position, it cannot rule out the possibility that such outcomes will be material to the consolidated results of operations for a particular reporting period in the future.

Segment information

Segment information	9 Months Ended
	Sep. 30, 2016
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 2015 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 also described in note 22 in the 2015 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. 14. Segment information, continued Information about the Company's segments is presented in the following table: Three months ended September 30 2016 2015 Total revenues(a) Inter- segment revenues Net income (loss) Total revenues(a) Inter- segment revenues Net income (loss) (in thousands) Business Banking $ 116,513 1,086 21,422 $ 112,650 1,167 23,995 Commercial Banking 268,683 950 102,796 270,554 1,097 108,422 Commercial Real Estate 205,562 463 90,065 181,478 469 85,312 Discretionary Portfolio 114,391 (14,795 ) 50,773 13,773 (5,365 ) 5,113 Residential Mortgage Banking 108,576 22,051 22,924 99,518 12,918 21,150 Retail Banking 353,016 3,052 69,506 308,520 3,292 64,721 All Other 182,949 (12,807 ) (7,502 ) 146,033 (13,578 ) (28,312 ) Total $ 1,349,690 — 349,984 $ 1,132,526 — 280,401 Nine months ended September 30 2016 2015 Total revenues(a) Inter- segment revenues Net income (loss) Total revenues(a) Inter- segment revenues Net income (loss) (in thousands) Business Banking $ 344,562 3,274 69,617 $ 332,341 3,334 74,160 Commercial Banking 787,781 2,917 309,515 774,392 3,281 312,926 Commercial Real Estate 575,117 1,299 254,682 535,909 978 250,501 Discretionary Portfolio 324,195 (43,726 ) 151,522 49,724 (16,184 ) 21,823 Residential Mortgage Banking 309,393 62,955 59,981 310,843 36,741 75,462 Retail Banking 1,037,727 9,198 204,291 914,484 9,688 202,415 All Other 575,885 (35,917 ) (65,065 ) 494,779 (37,838 ) (128,585 ) Total $ 3,954,660 — 984,543 $ 3,412,472 — 808,702 Average total assets Nine months ended September 30 Year ended December 31 2016 2015 2015 (in millions) Business Banking $ 5,442 5,321 5,339 Commercial Banking 25,363 24,041 24,143 Commercial Real Estate 20,571 18,632 18,827 Discretionary Portfolio 41,253 23,153 26,648 Residential Mortgage Banking 2,578 3,007 2,918 Retail Banking 11,739 10,912 11,035 All Other 16,951 12,279 12,870 Total $ 123,897 97,345 101,780 (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 pricing 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 $6,725,000 and $6,248,000 for the three-month periods ended September 30, 2016 and 2015, respectively, and $19,579,000 and $18,106,000 for the nine-month periods ended September 30, 2016 and 2015, 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.	9 Months Ended
	Sep. 30, 2016
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 $15 million at September 30, 2016. 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 $3.7 billion and $4.1 billion at September 30, 2016 and December 31, 2015, respectively. Revenues from those servicing rights were $5 million and $6 million for the quarters ended September 30, 2016 and 2015, respectively, and $15 million and $17 million for the nine months ended September 30, 2016 and 2015, respectively. The Company sub-services residential mortgage loans for Bayview Financial having outstanding principal balances totaling $32.1 billion and $37.7 billion at September 30, 2016 and December 31, 2015, respectively. Revenues earned for sub-servicing loans for Bayview Financial were $25 million and $26 million for the three-month periods ended September 30, 2016 and 2015, respectively, and $73 million and $91 million for the nine-month periods ended September 30, 2016 and 2015, respectively. In addition, the Company held $163 million and $181 million of mortgage-backed securities in its held-to-maturity portfolio at September 30, 2016 and December 31, 2015, respectively, that were securitized by Bayview Financial.

Sale of trust accounts

Sale of trust accounts	9 Months Ended
	Sep. 30, 2016
Discontinued Operations And Disposal Groups [Abstract]
Sale of trust accounts	16. Sale of trust accounts In April 2015, the Company sold the trade processing business within the retirement services division of its Institutional Client Services business. That sale resulted in an after-tax gain of $23 million ($45 million pre-tax) that reflected the allocation of approximately $11 million of previously recorded goodwill to the divested business. Revenues of the sold business had been included in “trust income” and were $9 million during the three months ended March 31, 2015. There were no revenues from the sold business recognized during the three months ended June 30, 2015 or thereafter. After considering related expenses, net income attributable to the business that was sold was not material to the consolidated results of operations of the Company.

Significant accounting polici25

Significant accounting policies (Policies)	9 Months Ended
	Sep. 30, 2016
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, 2015 (“2015 Annual Report”). 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)	9 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Schedule of Identifiable Assets Acquired and Liabilities Assumed	The consideration paid for Hudson City’s common equity and the amounts of identifiable assets acquired and liabilities assumed as of the acquisition date were as follows: (in thousands) Identifiable assets: Cash and due from banks $ 131,688 Interest-bearing deposits at banks 7,568,934 Investment securities 7,929,014 Loans 19,015,013 Goodwill 1,079,787 Core deposit intangible 131,665 Other assets 843,219 Total identifiable assets 36,699,320 Liabilities: Deposits 17,879,589 Borrowings 13,211,598 Other liabilities 405,025 Total liabilities 31,496,212 Total consideration $ 5,203,108 Cash paid $ 2,064,284 Common stock issued (25,953,950 shares) 3,110,581 Common stock awards converted 28,243 Total consideration $ 5,203,108
Pro Forma Information	Additionally, the Company expects to achieve operating cost savings and other business synergies as a result of the acquisition which are not reflected in the pro forma amounts that follow. Pro forma Pro forma Three months ended September 30, Nine months ended September 30, 2015 2015 (in thousands) Total revenues (a) $ 1,255,165 3,879,204 Net income 296,335 939,226 (a) Represents net interest income plus other income.
Summary of Merger-Related Expenses	A summary of merger-related expenses included in the consolidated statement of income follows: Nine months ended September 30, 2016 (in thousands) Salaries and employee benefits $ 5,334 Equipment and net occupancy 1,278 Printing, postage and supplies 1,482 Other cost of operations 27,661 Total $ 35,755

Investment securities (Tables)

Investment securities (Tables)	9 Months Ended
	Sep. 30, 2016
Investments Debt And Equity Securities [Abstract]
Amortized Cost and Estimated Fair Value of Investment Securities	The amortized cost and estimated fair value of investment securities were as follows: Amortized cost Gross unrealized gains Gross unrealized losses Estimated fair value (in thousands) September 30, 2016 Investment securities available for sale: U.S. Treasury and federal agencies $ 724,540 1,864 3 $ 726,401 Obligations of states and political subdivisions 4,912 108 5 5,015 Mortgage-backed securities: Government issued or guaranteed 10,617,605 314,088 1,031 10,930,662 Privately issued 52 — 1 51 Other debt securities 134,393 1,802 17,969 118,226 Equity securities 70,112 12,363 263 82,212 11,551,614 330,225 19,272 11,862,567 Investment securities held to maturity: Obligations of states and political subdivisions 72,258 458 220 72,496 Mortgage-backed securities: Government issued or guaranteed 2,168,460 83,630 215 2,251,875 Privately issued 163,489 1,616 39,122 125,983 Other debt securities 5,743 — — 5,743 2,409,950 85,704 39,557 2,456,097 Other securities 461,057 — — 461,057 Total $ 14,422,621 415,929 58,829 $ 14,779,721 December 31, 2015 Investment securities available for sale: U.S. Treasury and federal agencies $ 299,890 294 187 $ 299,997 Obligations of states and political subdivisions 5,924 146 42 6,028 Mortgage-backed securities: Government issued or guaranteed 11,592,959 142,370 48,701 11,686,628 Privately issued 74 2 2 74 Collateralized debt obligations 28,438 20,143 1,188 47,393 Other debt securities 137,556 1,514 20,190 118,880 Equity securities 73,795 10,230 354 83,671 12,138,636 174,699 70,664 12,242,671 Investment securities held to maturity: Obligations of states and political subdivisions 118,431 1,003 421 119,013 Mortgage-backed securities: Government issued or guaranteed 2,553,612 50,936 7,817 2,596,731 Privately issued 181,091 2,104 41,367 141,828 Other debt securities 6,575 — — 6,575 2,859,709 54,043 49,605 2,864,147 Other securities 554,059 — — 554,059 Total $ 15,552,404 228,742 120,269 $ 15,660,877
Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity	At September 30, 2016, the amortized cost and estimated fair value of debt securities by contractual maturity were as follows: Amortized cost Estimated fair value (in thousands) Debt securities available for sale: Due in one year or less $ 105,225 105,679 Due after one year through five years 625,911 627,585 Due after five years through ten years 3,968 4,538 Due after ten years 128,741 111,840 863,845 849,642 Mortgage-backed securities available for sale 10,617,657 10,930,713 $ 11,481,502 11,780,355 Debt securities held to maturity: Due in one year or less $ 25,141 25,301 Due after one year through five years 43,474 43,474 Due after five years through ten years 3,643 3,721 Due after ten years 5,743 5,743 78,001 78,239 Mortgage-backed securities held to maturity 2,331,949 2,377,858 $ 2,409,950 2,456,097
Investment Securities in Continuous Unrealized Loss Position	A summary of investment securities that as of September 30, 2016 and December 31, 2015 had been in a continuous unrealized loss position for less than twelve months and those that had been in a continuous unrealized loss position for twelve months or longer follows: Less than 12 months 12 months or more Fair value Unrealized losses Fair value Unrealized losses (in thousands) September 30, 2016 Investment securities available for sale: U.S. Treasury and federal agencies $ 3,355 (3 ) — — Obligations of states and political subdivisions — — 472 (5 ) Mortgage-backed securities: Government issued or guaranteed 224,128 (904 ) 7,294 (127 ) Privately issued — — 34 (1 ) Other debt securities — — 106,876 (17,969 ) Equity securities 767 (101 ) 138 (162 ) 228,250 (1,008 ) 114,814 (18,264 ) Investment securities held to maturity: Obligations of states and political subdivisions 19,557 (113 ) 11,050 (107 ) Mortgage-backed securities: Government issued or guaranteed 74,629 (46 ) 19,256 (169 ) Privately issued 17,542 (2,371 ) 91,127 (36,751 ) 111,728 (2,530 ) 121,433 (37,027 ) Total $ 339,978 (3,538 ) 236,247 (55,291 ) December 31, 2015 Investment securities available for sale: U.S. Treasury and federal agencies $ 147,508 (187 ) — — Obligations of states and political subdivisions 865 (2 ) 1,335 (40 ) Mortgage-backed securities: Government issued or guaranteed 4,061,899 (48,534 ) 7,216 (167 ) Privately issued — — 43 (2 ) Collateralized debt obligations 5,711 (335 ) 2,063 (853 ) Other debt securities 12,935 (462 ) 93,344 (19,728 ) Equity securities 18,073 (207 ) 153 (147 ) 4,246,991 (49,727 ) 104,154 (20,937 ) Investment securities held to maturity: Obligations of states and political subdivisions 42,913 (335) 5,853 (86) Mortgage-backed securities: Government issued or guaranteed 459,983 (1,801 ) 228,867 (6,016 ) Privately issued — — 112,155 (41,367 ) 502,896 (2,136 ) 346,875 (47,469 ) Total $ 4,749,887 (51,863 ) 451,029 (68,406 )

Loans and leases and the allo28

Loans and leases and the allowance for credit losses (Tables)	9 Months Ended
	Sep. 30, 2016
Receivables [Abstract]
Outstanding Principal Balance and Carrying Amount of Loans that is 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: September 30, December 31, 2016 2015 (in thousands) Outstanding principal balance $ 2,556,085 3,122,935 Carrying amount: Commercial, financial, leasing, etc. 62,244 78,847 Commercial real estate 504,406 644,284 Residential real estate 845,976 1,016,129 Consumer 609,400 725,807 $ 2,022,026 2,465,067
Summary of Changes in Accretable Yield for Acquired Loans	A summary of changes in the accretable yield for loans acquired at a discount for the three months and nine months ended September 30, 2016 and 2015 follows: Three months ended September 30 2016 2015 Purchased Other Purchased Other impaired acquired impaired acquired (in thousands) Balance at beginning of period $ 162,023 245,195 $ 77,624 344,989 Interest income (12,784 ) (26,540 ) (5,865 ) (37,396 ) Reclassifications from nonaccretable balance 2,256 12,050 47 769 Other (a) — (818 ) — 4,697 Balance at end of period $ 151,495 229,887 $ 71,806 313,059 Nine months ended September 30 2016 2015 Purchased Other Purchased Other impaired acquired impaired acquired (in thousands) Balance at beginning of period $ 184,618 296,434 $ 76,518 397,379 Interest income (40,906 ) (97,300 ) (16,843 ) (118,697 ) Reclassifications from nonaccretable balance 7,783 20,647 12,131 27,792 Other (a) — 10,106 — 6,585 Balance at end of period $ 151,495 229,887 $ 71,806 313,059 (a) Other changes in expected cash flows including changes in interest rates and prepayment assumptions.
Summary of Current, Past Due and Nonaccrual Loans	A summary of current, past due and nonaccrual loans as of September 30, 2016 and December 31, 2015 follows: Current 30-89 days past due Accruing loans past due 90 days or more (a) Accruing loans acquired at a discount past due 90 days or more (b) Purchased impaired (c) Nonaccrual Total September 30, 2016 (in thousands) Commercial, financial, leasing, etc. $ 21,601,646 70,597 10,831 1,893 795 231,401 $ 21,917,163 Real estate: Commercial 24,283,146 116,651 15,926 13,292 32,775 157,527 24,619,317 Residential builder and developer 1,814,299 16,993 4,476 3,262 18,096 20,118 1,877,244 Other commercial construction 5,525,684 20,238 — 198 15,412 20,669 5,582,201 Residential 18,438,396 494,767 281,023 12,510 401,551 213,896 19,842,143 Residential-limited documentation 3,400,578 105,621 — — 146,722 89,356 3,742,277 Consumer: Home equity lines and loans 5,586,704 40,406 — 13,014 1,640 79,623 5,721,387 Automobile 2,805,779 46,347 — 4 — 14,453 2,866,583 Other 3,410,790 31,033 5,026 21,009 — 10,319 3,478,177 Total $ 86,867,022 942,653 317,282 65,182 616,991 837,362 $ 89,646,492 December 31, 2015 Commercial, financial, leasing, etc. $ 20,122,648 52,868 2,310 693 1,902 241,917 $ 20,422,338 Real estate: Commercial (d) 23,111,673 172,439 12,963 8,790 46,790 179,606 23,532,261 Residential builder and developer 1,507,856 7,969 5,760 6,925 28,734 28,429 1,585,673 Other commercial construction (d) 3,962,620 65,932 7,936 2,001 24,525 16,363 4,079,377 Residential 20,507,551 560,312 284,451 16,079 488,599 153,281 22,010,273 Residential-limited documentation 3,885,073 137,289 — — 175,518 61,950 4,259,830 Consumer: Home equity lines and loans 5,805,222 45,604 — 15,222 2,261 84,467 5,952,776 Automobile 2,446,473 56,181 — 6 — 16,597 2,519,257 Other 3,051,435 36,702 4,021 18,757 — 16,799 3,127,714 Total $ 84,400,551 1,135,296 317,441 68,473 768,329 799,409 $ 87,489,499 (a) Excludes loans acquired at a discount. (b) Loans acquired at a discount that were recorded at fair value at acquisition date. This category does not include purchased impaired loans that are presented separately. (c) Accruing loans acquired at a discount that were impaired at acquisition date and recorded at fair value. (d) The Company expanded its definition of construction loans in 2016 and, as a result, re-characterized certain commercial real estate loans as other commercial construction loans. The December 31, 2015 balances reflect such changes.
Changes in Allowance for Credit Losses	Changes in the allowance for credit losses for the three months ended September 30, 2016 were as follows: Commercial, Financial, Real Estate Leasing, etc. Commercial Residential Consumer Unallocated Total (in thousands) Beginning balance $ 316,079 349,674 69,660 157,361 77,722 $ 970,496 Provision for credit losses 26,222 9,963 (6,232 ) 16,539 508 47,000 Net charge-offs Charge-offs (21,075 ) (1,564 ) (6,754 ) (29,882 ) — (59,275 ) Recoveries 6,958 1,704 1,919 7,319 — 17,900 Net charge-offs (14,117 ) 140 (4,835 ) (22,563 ) — (41,375 ) Ending balance $ 328,184 359,777 58,593 151,337 78,230 $ 976,121 Changes in the allowance for credit losses for the three months ended September 30, 2015 were as follows: Commercial, Financial, Real Estate Leasing, etc. Commercial Residential Consumer Unallocated Total (in thousands) Beginning balance $ 286,750 311,294 60,294 194,238 77,411 $ 929,987 Provision for credit losses 21,507 1,879 (3,155 ) 24,448 (679 ) 44,000 Net charge-offs Charge-offs (26,912 ) (2,203 ) (3,268 ) (20,758 ) — (53,141 ) Recoveries 5,322 2,119 1,125 4,386 — 12,952 Net charge-offs (21,590 ) (84 ) (2,143 ) (16,372 ) — (40,189 ) Ending balance $ 286,667 313,089 54,996 202,314 76,732 $ 933,798 Changes in the allowance for credit losses for the nine months ended September 30, 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 39,667 29,799 (610 ) 59,113 31 128,000 Net charge-offs Charge-offs (34,711 ) (3,569 ) (18,816 ) (107,761 ) — (164,857 ) Recoveries 22,824 6,716 5,781 21,665 — 56,986 Net charge-offs (11,887 ) 3,147 (13,035 ) (86,096 ) — (107,871 ) Ending balance $ 328,184 359,777 58,593 151,337 78,230 $ 976,121 Changes in the allowance for credit losses for the nine months ended September 30, 2015 were as follows: Commercial, Financial, Real Estate Leasing, etc. Commercial Residential Consumer Unallocated Total (in thousands) Beginning balance $ 288,038 307,927 61,910 186,033 75,654 $ 919,562 Provision for credit losses 32,686 13,769 (571 ) 65,038 1,078 112,000 Net charge-offs Charge-offs (46,990 ) (12,352 ) (9,695 ) (64,542 ) — (133,579 ) Recoveries 12,933 3,745 3,352 15,785 — 35,815 Net charge-offs (34,057 ) (8,607 ) (6,343 ) (48,757 ) — (97,764 ) Ending balance $ 286,667 313,089 54,996 202,314 76,732 $ 933,798
Impaired Loans and Leases	The following tables provide information with respect to loans and leases that were considered impaired as of September 30, 2016 and December 31, 2015 and for the three-month and nine-month periods ended September 30, 2016 and 2015. September 30, 2016 December 31, 2015 Recorded investment Unpaid principal balance Related allowance Recorded investment Unpaid principal balance Related allowance (in thousands) With an allowance recorded: Commercial, financial, leasing, etc. $ 192,805 212,009 55,020 179,037 195,821 44,752 Real estate: Commercial 75,749 85,137 14,939 85,974 95,855 18,764 Residential builder and developer 8,142 8,923 714 3,316 5,101 196 Other commercial construction 2,729 3,092 1,103 3,548 3,843 348 Residential 79,036 97,466 3,144 79,558 96,751 4,727 Residential-limited documentation 83,296 97,984 6,200 90,356 104,251 8,000 Consumer: Home equity lines and loans 42,862 46,844 7,697 25,220 26,195 3,777 Automobile 18,033 19,218 3,737 22,525 22,525 4,709 Other 4,122 5,122 864 17,620 17,620 4,820 506,774 575,795 93,418 507,154 567,962 90,093 With no related allowance recorded: Commercial, financial, leasing, etc. 72,429 80,757 — 93,190 110,735 — Real estate: Commercial 90,425 104,508 — 101,340 116,230 — Residential builder and developer 17,346 23,617 — 27,651 47,246 — Other commercial construction 18,265 37,432 — 13,221 31,477 — Residential 18,079 26,127 — 19,621 30,940 — Residential-limited documentation 17,611 27,936 — 18,414 31,113 — 234,155 300,377 — 273,437 367,741 — Total: Commercial, financial, leasing, etc. 265,234 292,766 55,020 272,227 306,556 44,752 Real estate: Commercial 166,174 189,645 14,939 187,314 212,085 18,764 Residential builder and developer 25,488 32,540 714 30,967 52,347 196 Other commercial construction 20,994 40,524 1,103 16,769 35,320 348 Residential 97,115 123,593 3,144 99,179 127,691 4,727 Residential-limited documentation 100,907 125,920 6,200 108,770 135,364 8,000 Consumer: Home equity lines and loans 42,862 46,844 7,697 25,220 26,195 3,777 Automobile 18,033 19,218 3,737 22,525 22,525 4,709 Other 4,122 5,122 864 17,620 17,620 4,820 Total $ 740,929 876,172 93,418 780,591 935,703 90,093
Interest Income Recognized on Impaired Loans	Three months ended September 30, 2016 Three months ended September 30, 2015 Interest income recognized Interest income recognized Average recorded investment Total Cash basis Average recorded investment Total Cash basis (in thousands) Commercial, financial, leasing, etc. $ 262,796 744 744 242,157 1,017 1,017 Real estate: Commercial 175,256 1,806 1,806 179,327 2,327 2,327 Residential builder and developer 26,996 405 405 53,009 81 81 Other commercial construction 21,500 190 190 17,236 1,943 1,943 Residential 96,961 1,572 570 99,939 1,835 1,316 Residential-limited documentation 101,877 1,501 378 116,191 1,539 618 Consumer: Home equity lines and loans 41,740 368 112 21,952 231 66 Automobile 18,571 303 19 24,429 391 39 Other 4,077 72 11 19,238 188 23 Total $ 749,774 6,961 4,235 773,478 9,552 7,430 Nine months ended September 30, 2016 Nine months ended September 30, 2015 Interest income recognized Interest income recognized Average recorded investment Total Cash basis Average recorded investment Total Cash basis (in thousands) Commercial, financial, leasing, etc. $ 283,783 7,055 7,055 226,243 2,123 2,123 Real estate: Commercial 177,579 3,891 3,891 161,834 4,433 4,433 Residential builder and developer 30,832 488 488 64,165 275 275 Other commercial construction 19,774 563 563 22,130 2,166 2,166 Residential 97,229 4,778 2,591 101,997 4,639 3,011 Residential-limited documentation 104,382 4,580 1,648 120,710 4,799 1,962 Consumer: Home equity lines and loans 33,998 937 295 20,619 656 179 Automobile 20,358 964 83 26,521 1,257 136 Other 10,987 371 74 19,053 547 86 Total $ 778,922 23,627 16,688 763,272 20,895 14,371
Summary of Loan Grades	Real Estate Commercial, Residential Other Financial, Builder and Commercial Leasing, etc. Commercial Developer Construction (in thousands) September 30, 2016 Pass $ 20,825,301 23,540,787 1,699,263 5,405,719 Criticized accrual 860,461 921,003 157,863 155,813 Criticized nonaccrual 231,401 157,527 20,118 20,669 Total $ 21,917,163 24,619,317 1,877,244 5,582,201 December 31, 2015 Pass $ 19,442,183 22,697,398 1,497,465 3,834,137 Criticized accrual 738,238 655,257 59,779 228,877 Criticized nonaccrual 241,917 179,606 28,429 16,363 Total $ 20,422,338 23,532,261 1,585,673 4,079,377
Allocation of Allowance for Credit Losses on Basis of Company's Impairment Methodology	The allocation of the allowance for credit losses summarized on the basis of the Company’s impairment methodology was as follows: Commercial, Financial, Real Estate Leasing, etc. Commercial Residential Consumer Total (in thousands) September 30, 2016 Individually evaluated for impairment $ 55,020 16,608 9,344 12,298 $ 93,270 Collectively evaluated for impairment 273,164 340,737 48,500 138,193 800,594 Purchased impaired — 2,432 749 846 4,027 Allocated $ 328,184 359,777 58,593 151,337 897,891 Unallocated 78,230 Total $ 976,121 December 31, 2015 Individually evaluated for impairment $ 44,752 19,175 12,727 13,306 $ 89,960 Collectively evaluated for impairment 255,615 307,000 57,624 163,511 783,750 Purchased impaired 37 656 1,887 1,503 4,083 Allocated $ 300,404 326,831 72,238 178,320 877,793 Unallocated 78,199 Total $ 955,992
Recorded Investment in Loans and Leases on Basis of Company's Impairment Methodology	The recorded investment in loans and leases summarized on the basis of the Company’s impairment methodology was as follows: Commercial, Financial, Real Estate Leasing, etc. Commercial Residential Consumer Total (in thousands) September 30, 2016 Individually evaluated for impairment $ 265,234 211,730 198,022 65,017 $ 740,003 Collectively evaluated for impairment 21,651,134 31,800,749 22,838,125 11,999,490 88,289,498 Purchased impaired 795 66,283 548,273 1,640 616,991 Total $ 21,917,163 32,078,762 23,584,420 12,066,147 $ 89,646,492 December 31, 2015 Individually evaluated for impairment $ 272,227 234,132 207,949 65,365 $ 779,673 Collectively evaluated for impairment 20,148,209 28,863,130 25,398,037 11,532,121 85,941,497 Purchased impaired 1,902 100,049 664,117 2,261 768,329 Total $ 20,422,338 29,197,311 26,270,103 11,599,747 $ 87,489,499
Loan Modification Activities that were Considered Troubled Debt Restructurings	The tables that follow summarize the Company’s loan modification activities that were considered troubled debt restructurings for the three months ended September 30, 2016 and 2015: Recorded investment Financial effects of modification Three months ended September 30, 2016 Number Pre- modification Post- modification Recorded investment (a) Interest (b) (dollars in thousands) Commercial, financial, leasing, etc. Principal deferral 30 $ 41,652 $ 40,183 $ (1,469 ) $ — Combination of concession types 13 27,834 19,802 (8,032 ) (6 ) Real estate: Commercial Principal deferral 14 12,302 11,644 (658 ) — Combination of concession types 4 2,623 2,614 (9 ) (172 ) Residential Principal deferral 21 4,489 4,714 225 — Combination of concession types 9 1,149 1,214 65 (120 ) Residential-limited documentation Principal deferral 3 435 470 35 — Combination of concession types 3 392 493 101 (123 ) Consumer: Home equity lines and loans Principal deferral 4 251 251 — — Combination of concession types 22 2,301 2,301 — (178 ) Automobile Principal deferral 10 186 186 — — Other Principal deferral 1 26 26 — — Total 134 $ 93,640 $ 83,898 $ (9,742 ) $ (599 ) (a) Financial effects impacting the recorded investment included principal payments or advances, charge-offs and capitalized escrow arrearages. (b) Represents the present value of interest rate concessions discounted at the effective rate of the original loan. Recorded investment Financial effects of modification Three months ended September 30, 2015 Number Pre- modification Post- modification Recorded investment (a) Interest (b) (dollars in thousands) Commercial, financial, leasing, etc. Principal deferral 36 $ 7,893 $ 7,419 $ (474 ) $ — Combination of concession types 1 31 31 — (6 ) Real estate: Commercial Principal deferral 15 4,230 4,208 (22 ) — Combination of concession types 1 1,156 1,169 13 (54 ) Other commercial construction Principal deferral 3 296 390 94 — Residential Principal deferral 31 3,540 3,743 203 — Other 1 267 267 — — Combination of concession types 10 1,296 1,380 84 (178 ) Residential-limited documentation Principal deferral 1 265 276 11 — Combination of concession types 4 605 662 57 (91 ) Consumer: Home equity lines and loans Principal deferral 4 727 727 — — Combination of concession types 22 2,003 2,003 — (199 ) Automobile Principal deferral 35 316 316 — — Other 15 93 93 — — Combination of concession types 25 471 471 — (17 ) Other Principal deferral 24 352 352 — — Other 5 33 33 — — Combination of concession types 12 117 117 — (12 ) Total 245 $ 23,691 $ 23,657 $ (34 ) $ (557 ) (a) Financial effects impacting the recorded investment included principal payments or advances, charge-offs and capitalized escrow arrearages. (b) Represents the present value of interest rate concessions discounted at the effective rate of the original loan. The tables below summarize the Company’s loan modification activities that were considered troubled debt restructurings for the nine months ended September 30, 2016 and 2015: Recorded investment Financial effects of modification Nine months ended September 30, 2016 Number Pre- modification Post- modification Recorded investment (a) Interest (b) (dollars in thousands) Commercial, financial, leasing, etc. Principal deferral 87 $ 98,956 $ 98,561 $ (395 ) $ — Combination of concession types 25 49,248 39,971 (9,277 ) (6 ) Real estate: Commercial Principal deferral 40 18,511 17,802 (709 ) — Interest rate reduction 1 129 129 — (25 ) Other 1 4,723 4,447 (276 ) — Combination of concession types 13 13,621 13,546 (75 ) (238 ) Residential builder and developer Principal deferral 3 23,905 22,958 (947 ) — Other commercial construction Principal deferral 1 250 250 — — Combination of concession types 1 124 124 — — Residential Principal deferral 46 7,433 7,945 512 — Combination of concession types 27 4,513 4,705 192 (120 ) Residential-limited documentation Principal deferral 6 711 803 92 — Combination of concession types 8 1,704 1,872 168 (462 ) Consumer: Home equity lines and loans Principal deferral 8 655 655 — — Combination of concession types 76 8,534 8,534 — (741 ) Automobile Principal deferral 102 865 865 — — Other 38 55 55 — — Combination of concession types 8 85 85 — (3 ) Other Principal deferral 56 951 951 — — Other 5 45 45 — — Combination of concession types 17 196 196 — (32 ) Total 569 $ 235,214 $ 224,499 $ (10,715 ) $ (1,627 ) (a) Financial effects impacting the recorded investment included principal payments or advances, charge-offs and capitalized escrow arrearages. (b) Represents the present value of interest rate concessions discounted at the effective rate of the original loan. Recorded investment Financial effects of modification Nine months ended September 30, 2015 Number Pre- modification Post- modification Recorded investment (a) Interest (b) (dollars in thousands) Commercial, financial, leasing, etc. Principal deferral 87 $ 25,483 $ 24,331 $ (1,152 ) $ — Interest rate reduction 1 99 99 — (19 ) Other 2 8,991 8,883 (108 ) — Combination of concession types 6 25,075 24,884 (191 ) (245 ) Real estate: Commercial Principal deferral 37 47,005 45,569 (1,436 ) — Combination of concession types 6 3,238 3,242 4 (159 ) Residential builder and developer Principal deferral 2 10,650 10,598 (52 ) — Other commercial construction Principal deferral 3 296 390 94 — Residential Principal deferral 50 4,954 5,239 285 — Other 1 267 267 — — Combination of concession types 22 2,551 2,795 244 (356 ) Residential-limited documentation Principal deferral 2 426 437 11 — Combination of concession types 7 1,239 1,298 59 (121 ) Consumer: Home equity lines and loans Principal deferral 6 1,946 1,946 — — Combination of concession types 41 3,555 3,555 — (424 ) Automobile Principal deferral 133 1,234 1,234 — — Interest rate reduction 7 137 137 — (10 ) Other 38 134 134 — — Combination of concession types 42 693 693 — (28 ) Other Principal deferral 73 1,418 1,418 — — Other 12 113 113 — — Combination of concession types 35 384 384 — (44 ) Total 613 $ 139,888 $ 137,646 $ (2,242 ) $ (1,406 ) (a) Financial effects impacting the recorded investment included principal payments or advances, charge-offs and capitalized escrow arrearages. (b) Represents the present value of interest rate concessions discounted at the effective rate of the original loan.

Shareholders' equity (Tables)

Shareholders' equity (Tables)	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Issued and Outstanding Preferred Stock	Issued and outstanding preferred stock of M&T as of September 30, 2016 and December 31, 2015 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 D (b) Fixed Rate Non-cumulative Perpetual Preferred Stock, $10,000 liquidation preference per share 50,000 $ 500,000 Series E (c) Fixed-to-Floating Rate Non-cumulative Perpetual Preferred Stock, $1,000 liquidation preference per share 350,000 $ 350,000 (a) Dividends, if declared, are paid at 6.375%. Warrants to purchase M&T common stock at $73.86 per share issued in connection with the Series A preferred stock expire in 2018 and totaled 713,855 at September 30, 2016 and 719,175 at December 31, 2015. (b) Dividends, if declared, are paid semi-annually at a rate of 6.875% per year. The shares became redeemable in whole or in part on June 15, 2016. (c) Dividends, if declared, are paid semi-annually at a rate of 6.45% through February 14, 2024 and thereafter will be paid quarterly at a rate of the three-month LIBOR plus 361 basis points (hundredths of one percent). The shares are redeemable in whole or in part on or after February 15, 2024. Notwithstanding M&T’s option to redeem the shares, if an event occurs such that the shares no longer qualify as Tier 1 capital, M&T may redeem all of the shares within 90 days following that occurrence.

Pension plans and other postr30

Pension plans and other postretirement benefits (Tables)	9 Months Ended
	Sep. 30, 2016
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 September 30 2016 2015 2016 2015 (in thousands) Service cost $ 6,259 5,916 399 188 Interest cost on projected benefit obligation 20,853 17,754 1,242 651 Expected return on plan assets (27,118 ) (23,527 ) — — Amortization of prior service credit (807 ) (1,501 ) (339 ) (340 ) Amortization of net actuarial loss 7,536 11,207 15 26 Net periodic benefit cost $ 6,723 9,849 1,317 525 Pension benefits Other postretirement benefits Nine months ended September 30 2016 2015 2016 2015 (in thousands) Service cost $ 18,778 17,748 1,197 562 Interest cost on projected benefit obligation 62,558 53,261 3,728 1,953 Expected return on plan assets (81,355 ) (70,578 ) — — Amortization of prior service credit (2,421 ) (4,504 ) (1,019 ) (1,019 ) Amortization of net actuarial loss 22,609 33,619 45 79 Net periodic benefit cost $ 20,169 29,546 3,951 1,575

Earnings per common share (Tabl

Earnings per common share (Tables)	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Computations of Basic Earnings Per Common Share	The computations of basic earnings per common share follow: Three months ended September 30 Nine months ended September 30 2016 2015 2016 2015 (in thousands, except per share) Income available to common shareholders: Net income $ 349,984 280,401 984,543 808,702 Less: Preferred stock dividends (a) (20,318 ) (20,318 ) (60,953 ) (60,953 ) Net income available to common equity 329,666 260,083 923,590 747,749 Less: Income attributable to unvested stock-based compensation awards (2,674 ) (2,746 ) (7,920 ) (8,122 ) Net income available to common shareholders $ 326,992 257,337 915,670 739,627 Weighted-average shares outstanding: Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards 156,767 134,049 158,710 133,805 Less: Unvested stock-based compensation awards (1,274 ) (1,419 ) (1,374 ) (1,458 ) Weighted-average shares outstanding 155,493 132,630 157,336 132,347 Basic earnings per common share $ 2.10 1.94 5.82 5.59 (a) Including impact of not as yet declared cumulative dividends.
Computations of Diluted Earnings Per Common Share	The computations of diluted earnings per common share follow: Three months ended September 30 Nine months ended September 30 2016 2015 2016 2015 (in thousands, except per share) Net income available to common equity $ 329,666 260,083 923,590 747,749 Less: Income attributable to unvested stock-based compensation awards (2,668 ) (2,737 ) (7,904 ) (8,093 ) Net income available to common shareholders $ 326,998 257,346 915,686 739,656 Adjusted weighted-average shares outstanding: Common and unvested stock-based compensation awards 156,767 134,049 158,710 133,805 Less: Unvested stock-based compensation awards (1,274 ) (1,419 ) (1,374 ) (1,458 ) Plus: Incremental shares from assumed conversion of stock-based compensation awards and warrants to purchase common stock 533 746 507 742 Adjusted weighted-average shares outstanding 156,026 133,376 157,843 133,089 Diluted earnings per common share $ 2.10 1.93 5.80 5.56

Comprehensive income (Tables)

Comprehensive income (Tables)	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Components of Other Comprehensive Income (Loss) and Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) to Net Income	The following tables displays 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, 2016 $ 16,359 62,849 (489,660 ) (4,093 ) $ (414,545 ) 162,918 $ (251,627 ) Other comprehensive income before reclassifications: Unrealized holding gains, net 1,228 234,438 — — 235,666 (92,714 ) 142,952 Foreign currency translation adjustment — — — (2,836 ) (2,836 ) 989 (1,847 ) Total other comprehensive income (loss) before reclassifications 1,228 234,438 — (2,836 ) 232,830 (91,725 ) 141,105 Amounts reclassified from accumulated other comprehensive income that (increase) decrease net income: Accretion of unrealized holding losses on held-to-maturity (“HTM”) securities — 2,998 — — 2,998 (b) (1,180 ) 1,818 Gains realized in net income — (28,748 ) — — (28,748 ) (c) 11,309 (17,439 ) Accretion of net gain on terminated cash flow hedges — — — (116 ) (116 ) (d) 46 (70 ) Amortization of prior service credit — — (3,440 ) — (3,440 ) (e) 1,354 (2,086 ) Amortization of actuarial losses — — 22,654 — 22,654 (e) (8,914 ) 13,740 Total reclassifications — (25,750 ) 19,214 (116 ) (6,652 ) 2,615 (4,037 ) Total gain (loss) during the period 1,228 208,688 19,214 (2,952 ) 226,178 (89,110 ) 137,068 Balance - September 30, 2016 $ 17,587 271,537 (470,446 ) (7,045 ) $ (188,367 ) 73,808 $ (114,559 ) Balance - January 1, 2015 $ 7,438 201,828 (503,027 ) (4,082 ) $ (297,843 ) 116,849 $ (180,994 ) Other comprehensive income before reclassifications: Unrealized holding gains (losses), net 9,699 (11,139 ) — — (1,440 ) 952 (488 ) Foreign currency translation adjustment — — — (735 ) (735 ) 214 (521 ) Gains on cash flow hedges — — — 1,453 1,453 (568 ) 885 Total other comprehensive income before reclassifications 9,699 (11,139 ) — 718 (722 ) 598 (124 ) Amounts reclassified from accumulated other comprehensive income that (increase) decrease net income: Accretion of unrealized holding losses on HTM securities — 2,417 — — 2,417 (b) (944 ) 1,473 Losses realized in net income — 108 — — 108 (c) (40 ) 68 Accretion of net gain on terminated cash flow hedges — — — (102 ) (102 ) (d) 40 (62 ) Amortization of prior service credit — — (5,523 ) — (5,523 ) (e) 2,359 (3,164 ) Amortization of actuarial losses — — 33,698 — 33,698 (e) (14,368 ) 19,330 Total reclassifications — 2,525 28,175 (102 ) 30,598 (12,953 ) 17,645 Total gain (loss) during the period 9,699 (8,614 ) 28,175 616 29,876 (12,355 ) 17,521 Balance - September 30, 2015 $ 17,137 193,214 (474,852 ) (3,466 ) $ (267,967 ) 104,494 $ (163,473 ) (a) Other-than-temporary impairment (b) Included in interest income (c) Included in gain (loss) on bank investment securities (d) Included in interest expense (e) Included in salaries and employee benefits expense
Accumulated Other Comprehensive Income (Loss), Net	Accumulated other comprehensive income (loss), net consisted of the following: Investment securities Defined benefit With OTTI All other plans Other Total (in thousands) Balance - December 31, 2015 $ 9,921 38,166 (296,979 ) (2,735 ) $ (251,627 ) Net gain (loss) during period 745 126,586 11,654 (1,917 ) 137,068 Balance - September 30, 2016 $ 10,666 164,752 (285,325 ) (4,652 ) $ (114,559 )

Derivative financial instrume33

Derivative financial instruments (Tables)	9 Months Ended
	Sep. 30, 2016
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Information about Interest Rate Swap Agreements	Information about interest rate swap agreements entered into for interest rate risk management purposes summarized by type of financial instrument the swap agreements were intended to hedge follows: Notional Average Weighted- average rate amount maturity Fixed Variable (in thousands) (in years) September 30, 2016 Fair value hedges: Fixed rate long-term borrowings (a) $ 1,400,000 0.9 4.42 % 1.79 % December 31, 2015 Fair value hedges: Fixed rate long-term borrowings (a) $ 1,400,000 1.7 4.42 % 1.39 % (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 September 30, 2016 December 31, 2015 September 30, 2016 December 31, 2015 (in thousands) Derivatives designated and qualifying as hedging instruments Fair value hedges: Interest rate swap agreements (a) $ 21,060 43,892 $ — — Commitments to sell real estate loans (a) 382 1,844 3,946 656 21,442 45,736 3,946 656 Derivatives not designated and qualifying as hedging instruments Mortgage-related commitments to originate real estate loans for sale (a) 29,851 10,282 51 403 Commitments to sell real estate loans (a) 626 533 8,437 846 Trading: Interest rate contracts (b) 346,453 203,517 286,298 153,723 Foreign exchange and other option and futures contracts (b) 7,092 8,569 6,415 7,022 384,022 222,901 301,201 161,994 Total derivatives $ 405,464 268,637 $ 305,147 162,650 (a) Asset derivatives are reported in other assets and liability derivatives are reported in other liabilities. (b) Asset derivatives are reported in trading account assets and liability derivatives are reported in other liabilities.
Information about Fair Values of Derivative Instruments in Consolidated Statement of Income	Amount of gain (loss) recognized Three months ended September 30, 2016 Three months ended September 30, 2015 Derivative Hedged item Derivative Hedged item (in thousands) Derivatives in fair value hedging relationships Interest rate swap agreements: Fixed rate long-term borrowings (a) $ (12,588 ) 12,587 $ (2,719 ) 2,382 Derivatives not designated as hedging instruments Trading: Interest rate contracts (b) $ 4,822 $ 4,120 Foreign exchange and other option and futures contracts (b) 1,746 2,613 Total $ 6,568 $ 6,733 Amount of gain (loss) recognized Nine months ended September 30, 2016 Nine months ended September 30, 2015 Derivative Hedged item Derivative Hedged item (in thousands) Derivatives in fair value hedging relationships Interest rate swap agreements: Fixed rate long-term borrowings (a) $ (22,832 ) 21,603 $ (12,469 ) 11,495 Derivatives not designated as hedging instruments Trading: Interest rate contracts (b) $ 11,578 $ 6,552 Foreign exchange and other option and futures contracts (b) 5,415 7,023 Total $ 16,993 $ 13,575 (a) Reported as other revenues from operations. (b) Reported as trading account and foreign exchange gains.

Fair value measurements (Tables

Fair value measurements (Tables)	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Estimated Fair Value on Recurring Basis	The following tables present assets and liabilities at September 30, 2016 and December 31, 2015 measured at estimated fair value on a recurring basis: Fair value measurements at September 30, 2016 Level 1 (a) Level 2 (a) Level 3 (in thousands) Trading account assets $ 488,588 50,699 437,889 — Investment securities available for sale: U.S. Treasury and federal agencies 726,401 — 726,401 — Obligations of states and political subdivisions 5,015 — 5,015 — Mortgage-backed securities: Government issued or guaranteed 10,930,662 — 10,930,662 — Privately issued 51 — — 51 Other debt securities 118,226 — 118,226 — Equity securities 82,212 62,546 19,666 — 11,862,567 62,546 11,799,970 51 Real estate loans held for sale 704,984 — 704,984 — Other assets (b) 51,919 — 22,068 29,851 Total assets $ 13,108,058 113,245 12,964,911 29,902 Trading account liabilities $ 292,713 — 292,713 — Other liabilities (b) 12,434 — 12,383 51 Total liabilities $ 305,147 — 305,096 51 Fair value measurements at December 31, 2015 Level 1(a) Level 2(a) Level 3 (in thousands) Trading account assets $ 273,783 56,763 217,020 — Investment securities available for sale: U.S. Treasury and federal agencies 299,997 — 299,997 — Obligations of states and political subdivisions 6,028 — 6,028 — Mortgage-backed securities: Government issued or guaranteed 11,686,628 — 11,686,628 — Privately issued 74 — — 74 Collateralized debt obligations 47,393 — — 47,393 Other debt securities 118,880 — 118,880 — Equity securities 83,671 65,178 18,493 — 12,242,671 65,178 12,130,026 47,467 Real estate loans held for sale 392,036 — 392,036 — Other assets (b) 56,551 — 46,269 10,282 Total assets $ 12,965,041 121,941 12,785,351 57,749 Trading account liabilities $ 160,745 — 160,745 — Other liabilities (b) 1,905 — 1,502 403 Total liabilities $ 162,650 — 162,247 403 (a) There were no significant transfers between Level 1 and Level 2 of the fair value hierarchy during the nine months ended September 30, 2016 and the year ended December 31, 2015. (b) Comprised predominantly of interest rate swap agreements used for interest rate risk management (Level 2), commitments to sell real estate loans (Level 2) and commitments to originate real estate loans to be held for sale (Level 3).
Changes in Level 3 Assets and Liabilities Measured at Estimated Fair Value on Recurring Basis	The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the three months ended September 30, 2016 were as follows: Investment securities available for Privately issued mortgage-backed securities Collateralized debt obligations Other assets and other liabilities (in thousands) Balance - June 30, 2016 $ 57 43,305 21,383 Total gains (losses) realized/unrealized: Included in earnings — 28,475 45,534 (b) Included in other comprehensive income — (15,050 ) (c) — Sales — (56,730 ) — Settlements (6 ) — — Transfers in and/or out of Level 3 (a) — — (37,117 ) (d) Balance - September 30, 2016 $ 51 — 29,800 Changes in unrealized gains included in earnings related to assets still held at September 30, 2016 $ — — 27,663 (b) The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the three months ended September 30, 2015 were as follows: Investment securities available for sale Privately issued mortgage-backed securities Collateralized debt obligations Other assets and other liabilities (in thousands) Balance - June 30, 2015 $ 88 50,483 11,206 Total gains (losses) realized/unrealized: Included in earnings — — 21,709 (b) Included in other comprehensive income — (472 ) (c) — Settlements (6 ) (135 ) — Transfers in and/or out of Level 3 (a) — — (15,268 ) (d) Balance - September 30, 2015 $ 82 49,876 17,647 Changes in unrealized gains included in earnings related to assets still held at September 30, 2015 $ — — 15,488 (b) The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the nine months ended September 30, 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 — 28,475 104,862 (b) Included in other comprehensive income — (18,268 ) (c) — Sales — (56,730 ) — Settlements (23 ) (870 ) — Transfers in and/or out of Level 3 (a) — — (84,941 ) (d) Balance – September 30, 2016 $ 51 — 29,800 Changes in unrealized gains included in earnings related to assets still held at September 30, 2016 $ — — 29,288 (b) The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the nine months ended September 30, 2015 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, 2015 $ 103 50,316 17,347 Total gains (losses) realized/unrealized: Included in earnings — — 67,611 (b) Included in other comprehensive income — 5,153 (c) — Settlements (21 ) (5,593 ) — Transfers in and/or out of Level 3 (a) — — (67,311 ) (d) Balance - September 30, 2015 $ 82 49,876 17,647 Changes in unrealized gains included in earnings related to assets still held at September 30, 2015 $ — — 15,965 (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 gains (losses) on investment securities in the consolidated statement of comprehensive income. (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 September 30, 2016 and December 31, 2015: Fair value at September 30, 2016 Valuation technique Unobservable input/assumptions Range (weighted- average) (in thousands) Recurring fair value measurements Privately issued mortgage-backed securities $ 51 Two independent pricing quotes — — Net other assets (liabilities) (a) 29,800 Discounted cash flow Commitment expirations 0%-92% (26%) Fair value at December 31, 2015 Valuation technique Unobservable input/assumptions Range (weighted- average) (in thousands) Recurring fair value measurements Privately issued mortgage-backed securities $ 74 Two independent pricing quotes — — Collateralized debt obligations 47,393 Discounted cash flow Probability of default 10%-56% (31%) Loss severity 100% Net other assets (liabilities) (a) 9,879 Discounted cash flow Commitment expirations 0%-60% (39%) (a) Other Level 3 assets (liabilities) consist of commitments to originate real estate loans.
Carrying Amounts and Estimated Fair Value for Financial Instrument Assets (Liabilities)	The carrying amounts and estimated fair value for financial instrument assets (liabilities) are presented in the following table: September 30, 2016 Carrying amount Estimated fair value Level 1 Level 2 Level 3 (in thousands) Financial assets: Cash and cash equivalents $ 1,332,202 1,332,202 1,258,882 73,320 — Interest-bearing deposits at banks 10,777,636 10,777,636 — 10,777,636 — Trading account assets 488,588 488,588 50,699 437,889 — Investment securities 14,733,574 14,779,721 62,546 14,591,141 126,034 Loans and leases: Commercial loans and leases 21,917,163 21,563,190 — — 21,563,190 Commercial real estate loans 32,078,762 31,944,341 — 290,347 31,653,994 Residential real estate loans 23,584,420 23,780,993 — 4,607,044 19,173,949 Consumer loans 12,066,147 12,009,873 — — 12,009,873 Allowance for credit losses (976,121 ) — — — — Loans and leases, net 88,670,371 89,298,397 — 4,897,391 84,401,006 Accrued interest receivable 311,414 311,414 — 311,414 — Financial liabilities: Noninterest-bearing deposits $ (33,127,627 ) (33,127,627 ) — (33,127,627 ) — Savings and interest-checking deposits (53,065,030 ) (53,065,030 ) — (53,065,030 ) — Time deposits (11,721,005 ) (11,829,119 ) — (11,829,119 ) — Deposits at Cayman Islands office (223,183 ) (223,183 ) — (223,183 ) — Short-term borrowings (213,846 ) (213,846 ) — (213,846 ) — Long-term borrowings (10,211,160 ) (10,277,155 ) — (10,277,155 ) — Accrued interest payable (76,230 ) (76,230 ) — (76,230 ) — Trading account liabilities (292,713 ) (292,713 ) — (292,713 ) — Other financial instruments: Commitments to originate real estate loans for sale $ 29,800 29,800 — — 29,800 Commitments to sell real estate loans (11,375 ) (11,375 ) — (11,375 ) — Other credit-related commitments (124,499 ) (124,499 ) — — (124,499 ) Interest rate swap agreements used for interest rate risk management 21,060 21,060 — 21,060 — December 31, 2015 Carrying amount Estimated fair value Level 1 Level 2 Level 3 (in thousands) Financial assets: Cash and cash equivalents $ 1,368,040 1,368,040 1,276,678 91,362 — Interest-bearing deposits at banks 7,594,350 7,594,350 — 7,594,350 — Trading account assets 273,783 273,783 56,763 217,020 — Investment securities 15,656,439 15,660,877 65,178 15,406,404 189,295 Loans and leases: Commercial loans and leases 20,422,338 20,146,201 — — 20,146,201 Commercial real estate loans 29,197,311 29,044,244 — 38,774 29,005,470 Residential real estate loans 26,270,103 26,267,771 — 4,727,816 21,539,955 Consumer loans 11,599,747 11,550,270 — — 11,550,270 Allowance for credit losses (955,992 ) — — — — Loans and leases, net 86,533,507 87,008,486 — 4,766,590 82,241,896 Accrued interest receivable 306,496 306,496 — 306,496 — Financial liabilities: Noninterest-bearing deposits $ (29,110,635 ) (29,110,635 ) — (29,110,635 ) — Savings and interest-checking deposits (49,566,644 ) (49,566,644 ) — (49,566,644 ) — Time deposits (13,110,392 ) (13,135,042 ) — (13,135,042 ) — Deposits at Cayman Islands office (170,170 ) (170,170 ) — (170,170 ) — Short-term borrowings (2,132,182 ) (2,132,182 ) — (2,132,182 ) — Long-term borrowings (10,653,858 ) (10,639,556 ) — (10,639,556 ) — Accrued interest payable (85,145 ) (85,145 ) — (85,145 ) — Trading account liabilities (160,745 ) (160,745 ) — (160,745 ) — Other financial instruments: Commitments to originate real estate loans for sale $ 9,879 9,879 — — 9,879 Commitments to sell real estate loans 875 875 — 875 — Other credit-related commitments (122,334 ) (122,334 ) — — (122,334 ) Interest rate swap agreements used for interest rate risk management 43,892 43,892 — 43,892 —

Commitments and contingencies (

Commitments and contingencies (Tables)	9 Months Ended
	Sep. 30, 2016
Commitments And Contingencies Disclosure [Abstract]
Company's Significant Commitments	The following table presents the Company's significant commitments. Certain of these commitments are not included in the Company's consolidated balance sheet. September 30, December 31, 2016 2015 (in thousands) Commitments to extend credit Home equity lines of credit $ 5,525,814 5,631,680 Commercial real estate loans to be sold 403,411 57,597 Other commercial real estate 6,365,999 5,949,933 Residential real estate loans to be sold 635,661 488,621 Other residential real estate 297,191 212,619 Commercial and other 12,219,005 11,802,850 Standby letters of credit 3,283,270 3,330,013 Commercial letters of credit 50,109 55,559 Financial guarantees and indemnification contracts 3,147,784 2,794,322 Commitments to sell real estate loans 1,538,900 782,885

Segment information (Tables)

Segment information (Tables)	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Information about Company's Segments	Information about the Company's segments is presented in the following table: Three months ended September 30 2016 2015 Total revenues(a) Inter- segment revenues Net income (loss) Total revenues(a) Inter- segment revenues Net income (loss) (in thousands) Business Banking $ 116,513 1,086 21,422 $ 112,650 1,167 23,995 Commercial Banking 268,683 950 102,796 270,554 1,097 108,422 Commercial Real Estate 205,562 463 90,065 181,478 469 85,312 Discretionary Portfolio 114,391 (14,795 ) 50,773 13,773 (5,365 ) 5,113 Residential Mortgage Banking 108,576 22,051 22,924 99,518 12,918 21,150 Retail Banking 353,016 3,052 69,506 308,520 3,292 64,721 All Other 182,949 (12,807 ) (7,502 ) 146,033 (13,578 ) (28,312 ) Total $ 1,349,690 — 349,984 $ 1,132,526 — 280,401 Nine months ended September 30 2016 2015 Total revenues(a) Inter- segment revenues Net income (loss) Total revenues(a) Inter- segment revenues Net income (loss) (in thousands) Business Banking $ 344,562 3,274 69,617 $ 332,341 3,334 74,160 Commercial Banking 787,781 2,917 309,515 774,392 3,281 312,926 Commercial Real Estate 575,117 1,299 254,682 535,909 978 250,501 Discretionary Portfolio 324,195 (43,726 ) 151,522 49,724 (16,184 ) 21,823 Residential Mortgage Banking 309,393 62,955 59,981 310,843 36,741 75,462 Retail Banking 1,037,727 9,198 204,291 914,484 9,688 202,415 All Other 575,885 (35,917 ) (65,065 ) 494,779 (37,838 ) (128,585 ) Total $ 3,954,660 — 984,543 $ 3,412,472 — 808,702 Average total assets Nine months ended September 30 Year ended December 31 2016 2015 2015 (in millions) Business Banking $ 5,442 5,321 5,339 Commercial Banking 25,363 24,041 24,143 Commercial Real Estate 20,571 18,632 18,827 Discretionary Portfolio 41,253 23,153 26,648 Residential Mortgage Banking 2,578 3,007 2,918 Retail Banking 11,739 10,912 11,035 All Other 16,951 12,279 12,870 Total $ 123,897 97,345 101,780 (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 pricing 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 $6,725,000 and $6,248,000 for the three-month periods ended September 30, 2016 and 2015, respectively, and $19,579,000 and $18,106,000 for the nine-month periods ended September 30, 2016 and 2015, 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.

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail)	Nov. 01, 2015USD ($)Officeshares	Nov. 30, 2015USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Business Acquisition [Line Items]
Proceeds from sales of investment securities					$ 61,947,000	$ 2,579,000
Goodwill			$ 4,593,112,000		$ 4,593,112,000		$ 4,593,112,000
Hudson City [Member]
Business Acquisition [Line Items]
Number of banking offices acquired in New Jersey, Connecticut and New York | Office	135
Gross amount of cash paid in the acquisition	$ 2,064,284,000
Business acquisition, purchase price	5,203,108,000
Proceeds from sales of investment securities		$ 5,800,000,000
Repayments of borrowings assumed in acquisition		$ 10,600,000,000
Goodwill	1,079,787,000
Core deposit intangible	$ 131,665,000
Amortization period of core deposit intangible					7 years
Other- than-temporary impairment				$ 23,000,000		97,000,000
Merger-related expenses			$ 0	$ 0	$ 35,755,000	$ 0
Hudson City [Member] | Common Stock [Member]
Business Acquisition [Line Items]
Shares issued upon acquisition | shares	25,953,950

Acquisitions - Schedule of Iden

Acquisitions - Schedule of Identifiable Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Nov. 01, 2015	Sep. 30, 2016	Dec. 31, 2015
Identifiable assets:
Goodwill		$ 4,593,112	$ 4,593,112
Hudson City [Member]
Identifiable assets:
Cash and due from banks	$ 131,688
Interest-bearing deposits at banks	7,568,934
Investment securities	7,929,014
Loans	19,015,013
Goodwill	1,079,787
Core deposit intangible	131,665
Other assets	843,219
Total identifiable assets	36,699,320
Liabilities:
Deposits	17,879,589
Borrowings	13,211,598
Other liabilities	405,025
Total liabilities	31,496,212
Total consideration	5,203,108
Cash paid	2,064,284
Common stock awards converted	28,243
Total consideration	5,203,108
Hudson City [Member] | Common Stock [Member]
Liabilities:
Common stock issued (25,953,950 shares)	$ 3,110,581

Acquisitions - Schedule of Id39

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

Acquisitions - Pro Forma Inform

Acquisitions - Pro Forma Information (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015
Business Acquisition Pro Forma Information [Abstract]
Total revenues	$ 1,255,165	$ 3,879,204
Net income	$ 296,335	$ 939,226

Acquisitions - Summary of Merge

Acquisitions - Summary of Merger-Related Expenses (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Summary of merger-related expenses
Salaries and employee benefits	$ 399,786,000	$ 363,567,000	$ 1,230,246,000	$ 1,115,117,000
Equipment and net occupancy	75,263,000	68,470,000	225,165,000	201,792,000
Printing, postage and supplies	8,972,000	8,691,000	30,865,000	27,586,000
Other costs of operations	230,125,000	197,908,000	682,528,000	642,925,000
Hudson City [Member]
Summary of merger-related expenses
Salaries and employee benefits			5,334,000
Equipment and net occupancy			1,278,000
Printing, postage and supplies			1,482,000
Other costs of operations			27,661,000
Total	$ 0	$ 0	$ 35,755,000	$ 0

Investment Securities - Amortiz

Investment Securities - Amortized Cost and Estimated Fair Value of Investment Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	$ 11,551,614	$ 12,138,636
Investment securities available for sale, gross unrealized gains	330,225	174,699
Investment securities available for sale, gross unrealized losses	19,272	70,664
Investment securities available for sale, estimated fair value	11,862,567	12,242,671
Amortized cost for held to maturity	2,409,950	2,859,709
Gross unrealized gains for held to maturity	85,704	54,043
Gross unrealized losses for held to maturity	39,557	49,605
Estimated fair value for held to maturity	2,456,097	2,864,147
Other securities, Amortized cost	461,057	554,059
Other securities, Gross unrealized gains	0	0
Other securities, Gross unrealized losses	0	0
Other, fair value	461,057	554,059
Total Amortized cost	14,422,621	15,552,404
Total for Gross unrealized gains	415,929	228,742
Total for Gross unrealized losses	58,829	120,269
Total for Estimated fair value	14,779,721	15,660,877
U.S. Treasury and Federal Agencies [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	724,540	299,890
Investment securities available for sale, gross unrealized gains	1,864	294
Investment securities available for sale, gross unrealized losses	3	187
Investment securities available for sale, estimated fair value	726,401	299,997
Obligations of States and Political Subdivisions [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	4,912	5,924
Investment securities available for sale, gross unrealized gains	108	146
Investment securities available for sale, gross unrealized losses	5	42
Investment securities available for sale, estimated fair value	5,015	6,028
Amortized cost for held to maturity	72,258	118,431
Gross unrealized gains for held to maturity	458	1,003
Gross unrealized losses for held to maturity	220	421
Estimated fair value for held to maturity	72,496	119,013
Government Issued or Guaranteed [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	10,617,605	11,592,959
Investment securities available for sale, gross unrealized gains	314,088	142,370
Investment securities available for sale, gross unrealized losses	1,031	48,701
Investment securities available for sale, estimated fair value	10,930,662	11,686,628
Amortized cost for held to maturity	2,168,460	2,553,612
Gross unrealized gains for held to maturity	83,630	50,936
Gross unrealized losses for held to maturity	215	7,817
Estimated fair value for held to maturity	2,251,875	2,596,731
Privately Issued [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	52	74
Investment securities available for sale, gross unrealized gains		2
Investment securities available for sale, gross unrealized losses	1	2
Investment securities available for sale, estimated fair value	51	74
Amortized cost for held to maturity	163,489	181,091
Gross unrealized gains for held to maturity	1,616	2,104
Gross unrealized losses for held to maturity	39,122	41,367
Estimated fair value for held to maturity	125,983	141,828
Collateralized Debt Obligations [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost		28,438
Investment securities available for sale, gross unrealized gains		20,143
Investment securities available for sale, gross unrealized losses		1,188
Investment securities available for sale, estimated fair value		47,393
Other Debt Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	134,393	137,556
Investment securities available for sale, gross unrealized gains	1,802	1,514
Investment securities available for sale, gross unrealized losses	17,969	20,190
Investment securities available for sale, estimated fair value	118,226	118,880
Amortized cost for held to maturity	5,743	6,575
Estimated fair value for held to maturity	5,743	6,575
Equity Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	70,112	73,795
Investment securities available for sale, gross unrealized gains	12,363	10,230
Investment securities available for sale, gross unrealized losses	263	354
Investment securities available for sale, estimated fair value	$ 82,212	$ 83,671

Investment Securities - Additio

Investment Securities - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2016USD ($)Investment	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)Investment	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Investment Holdings [Line Items]
Gross realized gains on sale of investment securities	$ 0	$ 0	$ 0	$ 0
Number of investment securities with aggregate gross unrealized losses | Investment	504		504
Unrealized losses on individual investment securities	$ 58,829,000		$ 58,829,000		$ 120,269,000
Cost method investment securities	461,000,000		$ 461,000,000
Collateralized Debt Obligations [Member]
Investment Holdings [Line Items]
Net gain on securities sold	$ 28,000,000

Investment Securities - Amort44

Investment Securities - Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Debt securities available for sale:
Due in one year or less	$ 105,225
Due after one year through five years	625,911
Due after five years through ten years	3,968
Due after ten years	128,741
Total available for sale (amortized cost)	863,845
Mortgage-backed securities available for sale	10,617,657
Total	11,481,502
Debt securities held to maturity:
Due in one year or less	25,141
Due after one year through five years	43,474
Due after five years through ten years	3,643
Due after ten years	5,743
Total available for held to maturity (amortized cost)	78,001
Mortgage-backed securities held to maturity	2,331,949
Amortized cost for held to maturity	2,409,950	$ 2,859,709
Debt securities available for sale:
Due in one year or less	105,679
Due after one year through five years	627,585
Due after five years through ten years	4,538
Due after ten years	111,840
Total available for sale (fair value)	849,642
Mortgage-backed securities available for sale	10,930,713
Total	11,780,355
Debt securities held to maturity:
Due in one year or less	25,301
Due after one year through five years	43,474
Due after five years through ten years	3,721
Due after ten years	5,743
Total available for held to maturity (fair value)	78,239
Mortgage-backed securities held to maturity	2,377,858
Total	$ 2,456,097	$ 2,864,147

Investment Securities - Investm

Investment Securities - Investment Securities in Continuous Unrealized Loss Position (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months	$ 228,250	$ 4,246,991
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses	(1,008)	(49,727)
Estimated fair value, 12 months or more	114,814	104,154
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(18,264)	(20,937)
Held to maturity, Estimated fair value, Less than 12 months	111,728	502,896
Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses	(2,530)	(2,136)
Held to maturity, Estimated fair value, 12 months or more	121,433	346,875
Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses	(37,027)	(47,469)
Total investment securities, fair value less than 12 months	339,978	4,749,887
Investment Securities Continuous Unrealized Loss Position Less Than Twelve Months Aggregate Losses	(3,538)	(51,863)
Total of investment securities, fair value, 12 Months or More	236,247	451,029
Investment Securities Continuous Unrealized Loss Position Twelve Months or Longer Aggregate Losses	(55,291)	(68,406)
U.S. Treasury and Federal Agencies [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months	3,355	147,508
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses	(3)	(187)
Obligations of States and Political Subdivisions [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months		865
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses		(2)
Estimated fair value, 12 months or more	472	1,335
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(5)	(40)
Held to maturity, Estimated fair value, Less than 12 months	19,557	42,913
Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses	(113)	(335)
Held to maturity, Estimated fair value, 12 months or more	11,050	5,853
Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses	(107)	(86)
Government Issued or Guaranteed [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months	224,128	4,061,899
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses	(904)	(48,534)
Estimated fair value, 12 months or more	7,294	7,216
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(127)	(167)
Held to maturity, Estimated fair value, Less than 12 months	74,629	459,983
Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses	(46)	(1,801)
Held to maturity, Estimated fair value, 12 months or more	19,256	228,867
Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses	(169)	(6,016)
Privately Issued Mortgage-Backed Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, 12 months or more	34	43
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(1)	(2)
Collateralized Debt Obligations [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months		5,711
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses		(335)
Estimated fair value, 12 months or more		2,063
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses		(853)
Other Debt Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months		12,935
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses		(462)
Estimated fair value, 12 months or more	106,876	93,344
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(17,969)	(19,728)
Equity Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months	767	18,073
Available For Sale Securities Continuous Unrealized Losses Position Less Than Twelve Months Aggregate Losses	(101)	(207)
Estimated fair value, 12 months or more	138	153
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(162)	(147)
Privately Issued [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Held to maturity, Estimated fair value, Less than 12 months	17,542
Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses	(2,371)
Held to maturity, Estimated fair value, 12 months or more	91,127	112,155
Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses	$ (36,751)	$ (41,367)

Loans and Leases and the Allo46

Loans and Leases and the Allowance for Credit Losses - Outstanding Principal Balance and Carrying Amount of Loans that is Included in Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Outstanding principal and carrying value of acquired loans recorded at fair value
Outstanding principal balance	$ 2,556,085	$ 3,122,935
Carrying amount	2,022,026	2,465,067
Commercial, Financial, Leasing, etc. [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	62,244	78,847
Commercial Real Estate [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	504,406	644,284
Residential Real Estate [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	845,976	1,016,129
Consumer [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	$ 609,400	$ 725,807

Loans and Leases and the Allo47

Loans and Leases and the Allowance for Credit Losses - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Loans And Leases Receivable [Line Items]
Contractual principal and interest payments	$ 617	$ 768
Commercial real estate loans held for sale	$ 290	39
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	$ 148	172
Loans secured by residential real estate that were in the process of foreclosure	321	315
Loans secured by residential real estate that were in the process of foreclosure, serviced by other entities	$ 246
Percentage loans in the process of foreclosure, serviced by other entities, classified as purchased impaired	61.00%
Percentage loans in the process of foreclosure, serviced by other entities, classified as government guaranteed	21.00%
Residential Mortgage Loans [Member]
Loans And Leases Receivable [Line Items]
Mortgage loans held for sale	$ 415	353
Carrying value of loans for which partial charge-off has been recognized	47	55
Mortgage loans on real real estate not requiring charge off due to collateral carrying amount	20	20
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	33	21
Mortgage loans on real real estate not requiring charge off due to collateral carrying amount	$ 38	$ 28
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 Allo48

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		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Purchased Impaired [Member]
Summary of changes in Accretable Yield for acquired loans
Balance at beginning of period	$ 162,023	$ 77,624	$ 184,618	$ 76,518
Interest income	(12,784)	(5,865)	(40,906)	(16,843)
Reclassifications from nonaccretable balance	2,256	47	7,783	12,131
Balance at end of period	151,495	71,806	151,495	71,806
Other Acquired [Member]
Summary of changes in Accretable Yield for acquired loans
Balance at beginning of period	245,195	344,989	296,434	397,379
Interest income	(26,540)	(37,396)	(97,300)	(118,697)
Reclassifications from nonaccretable balance	12,050	769	20,647	27,792
Other	(818)	4,697	10,106	6,585
Balance at end of period	$ 229,887	$ 313,059	$ 229,887	$ 313,059

Loans and Leases and the Allo49

Loans and Leases and the Allowance for Credit Losses - Summary of Current, Past Due and Nonaccrual Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	$ 86,867,022	$ 84,400,551
30-89 days past due	942,653	1,135,296
Accruing loans past due 90 days or more	317,282	317,441
Purchased impaired	616,991	768,329
Nonaccrual	837,362	799,409
Loans and leases, net of unearned discount	89,646,492	87,489,499
Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans past due 90 days or more	65,182	68,473
Commercial, Financial, Leasing, etc. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	21,601,646	20,122,648
30-89 days past due	70,597	52,868
Accruing loans past due 90 days or more	10,831	2,310
Purchased impaired	795	1,902
Nonaccrual	231,401	241,917
Loans and leases, net of unearned discount	21,917,163	20,422,338
Commercial, Financial, Leasing, etc. [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans past due 90 days or more	1,893	693
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	24,283,146	23,111,673
30-89 days past due	116,651	172,439
Accruing loans past due 90 days or more	15,926	12,963
Purchased impaired	32,775	46,790
Nonaccrual	157,527	179,606
Loans and leases, net of unearned discount	24,619,317	23,532,261
Commercial [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans past due 90 days or more	13,292	8,790
Residential Builder and Developer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,814,299	1,507,856
30-89 days past due	16,993	7,969
Accruing loans past due 90 days or more	4,476	5,760
Purchased impaired	18,096	28,734
Nonaccrual	20,118	28,429
Loans and leases, net of unearned discount	1,877,244	1,585,673
Residential Builder and Developer [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans past due 90 days or more	3,262	6,925
Other Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	5,525,684	3,962,620
30-89 days past due	20,238	65,932
Accruing loans past due 90 days or more		7,936
Purchased impaired	15,412	24,525
Nonaccrual	20,669	16,363
Loans and leases, net of unearned discount	5,582,201	4,079,377
Other Commercial Construction [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans past due 90 days or more	198	2,001
Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	18,438,396	20,507,551
30-89 days past due	494,767	560,312
Accruing loans past due 90 days or more	281,023	284,451
Purchased impaired	401,551	488,599
Nonaccrual	213,896	153,281
Loans and leases, net of unearned discount	19,842,143	22,010,273
Residential [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans past due 90 days or more	12,510	16,079
Residential Limited Documentation [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	3,400,578	3,885,073
30-89 days past due	105,621	137,289
Purchased impaired	146,722	175,518
Nonaccrual	89,356	61,950
Loans and leases, net of unearned discount	3,742,277	4,259,830
Home Equity Lines and Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	5,586,704	5,805,222
30-89 days past due	40,406	45,604
Purchased impaired	1,640	2,261
Nonaccrual	79,623	84,467
Loans and leases, net of unearned discount	5,721,387	5,952,776
Home Equity Lines and Loans [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans past due 90 days or more	13,014	15,222
Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	2,805,779	2,446,473
30-89 days past due	46,347	56,181
Nonaccrual	14,453	16,597
Loans and leases, net of unearned discount	2,866,583	2,519,257
Automobile [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans past due 90 days or more	4	6
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	3,410,790	3,051,435
30-89 days past due	31,033	36,702
Accruing loans past due 90 days or more	5,026	4,021
Nonaccrual	10,319	16,799
Loans and leases, net of unearned discount	3,478,177	3,127,714
Other [Member] | Accruing Loans Acquired at Discount [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing loans past due 90 days or more	$ 21,009	$ 18,757

Loans and Leases and the Allo50

Loans and Leases and the Allowance for Credit Losses - Changes in Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$ 970,496	$ 929,987	$ 955,992	$ 919,562
Provision for credit losses	47,000	44,000	128,000	112,000
Net charge-offs
Charge-offs	(59,275)	(53,141)	(164,857)	(133,579)
Recoveries	17,900	12,952	56,986	35,815
Net charge-offs	(41,375)	(40,189)	(107,871)	(97,764)
Ending balance	976,121	933,798	976,121	933,798
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	316,079	286,750	300,404	288,038
Provision for credit losses	26,222	21,507	39,667	32,686
Net charge-offs
Charge-offs	(21,075)	(26,912)	(34,711)	(46,990)
Recoveries	6,958	5,322	22,824	12,933
Net charge-offs	(14,117)	(21,590)	(11,887)	(34,057)
Ending balance	328,184	286,667	328,184	286,667
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	349,674	311,294	326,831	307,927
Provision for credit losses	9,963	1,879	29,799	13,769
Net charge-offs
Charge-offs	(1,564)	(2,203)	(3,569)	(12,352)
Recoveries	1,704	2,119	6,716	3,745
Net charge-offs	140	(84)	3,147	(8,607)
Ending balance	359,777	313,089	359,777	313,089
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	69,660	60,294	72,238	61,910
Provision for credit losses	(6,232)	(3,155)	(610)	(571)
Net charge-offs
Charge-offs	(6,754)	(3,268)	(18,816)	(9,695)
Recoveries	1,919	1,125	5,781	3,352
Net charge-offs	(4,835)	(2,143)	(13,035)	(6,343)
Ending balance	58,593	54,996	58,593	54,996
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	157,361	194,238	178,320	186,033
Provision for credit losses	16,539	24,448	59,113	65,038
Net charge-offs
Charge-offs	(29,882)	(20,758)	(107,761)	(64,542)
Recoveries	7,319	4,386	21,665	15,785
Net charge-offs	(22,563)	(16,372)	(86,096)	(48,757)
Ending balance	151,337	202,314	151,337	202,314
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	77,722	77,411	78,199	75,654
Provision for credit losses	508	(679)	31	1,078
Net charge-offs
Ending balance	$ 78,230	$ 76,732	$ 78,230	$ 76,732

Loans and Leases and the Allo51

Loans and Leases and the Allowance for Credit Losses - Impaired Loans and Leases (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Financing Receivable, Impaired [Line Items]
Recorded investment with related allowance	$ 506,774	$ 507,154
Unpaid principal balance with related allowance	575,795	567,962
Related allowance	93,418	90,093
Recorded investment with no related allowance	234,155	273,437
Unpaid principal balance with no related allowance	300,377	367,741
Recorded investment	740,929	780,591
Unpaid principal balance	876,172	935,703
Related allowance	93,418	90,093
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment with related allowance	75,749	85,974
Unpaid principal balance with related allowance	85,137	95,855
Related allowance	14,939	18,764
Recorded investment with no related allowance	90,425	101,340
Unpaid principal balance with no related allowance	104,508	116,230
Recorded investment	166,174	187,314
Unpaid principal balance	189,645	212,085
Related allowance	14,939	18,764
Automobile [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment with related allowance	18,033	22,525
Unpaid principal balance with related allowance	19,218	22,525
Related allowance	3,737	4,709
Recorded investment	18,033	22,525
Unpaid principal balance	19,218	22,525
Related allowance	3,737	4,709
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment with related allowance	192,805	179,037
Unpaid principal balance with related allowance	212,009	195,821
Related allowance	55,020	44,752
Recorded investment with no related allowance	72,429	93,190
Unpaid principal balance with no related allowance	80,757	110,735
Recorded investment	265,234	272,227
Unpaid principal balance	292,766	306,556
Related allowance	55,020	44,752
Residential Builder and Developer [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment with related allowance	8,142	3,316
Unpaid principal balance with related allowance	8,923	5,101
Related allowance	714	196
Recorded investment with no related allowance	17,346	27,651
Unpaid principal balance with no related allowance	23,617	47,246
Recorded investment	25,488	30,967
Unpaid principal balance	32,540	52,347
Related allowance	714	196
Other Commercial Construction [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment with related allowance	2,729	3,548
Unpaid principal balance with related allowance	3,092	3,843
Related allowance	1,103	348
Recorded investment with no related allowance	18,265	13,221
Unpaid principal balance with no related allowance	37,432	31,477
Recorded investment	20,994	16,769
Unpaid principal balance	40,524	35,320
Related allowance	1,103	348
Residential [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment with related allowance	79,036	79,558
Unpaid principal balance with related allowance	97,466	96,751
Related allowance	3,144	4,727
Recorded investment with no related allowance	18,079	19,621
Unpaid principal balance with no related allowance	26,127	30,940
Recorded investment	97,115	99,179
Unpaid principal balance	123,593	127,691
Related allowance	3,144	4,727
Residential Limited Documentation [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment with related allowance	83,296	90,356
Unpaid principal balance with related allowance	97,984	104,251
Related allowance	6,200	8,000
Recorded investment with no related allowance	17,611	18,414
Unpaid principal balance with no related allowance	27,936	31,113
Recorded investment	100,907	108,770
Unpaid principal balance	125,920	135,364
Related allowance	6,200	8,000
Home Equity Lines and Loans [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment with related allowance	42,862	25,220
Unpaid principal balance with related allowance	46,844	26,195
Related allowance	7,697	3,777
Recorded investment	42,862	25,220
Unpaid principal balance	46,844	26,195
Related allowance	7,697	3,777
Other [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment with related allowance	4,122	17,620
Unpaid principal balance with related allowance	5,122	17,620
Related allowance	864	4,820
Recorded investment	4,122	17,620
Unpaid principal balance	5,122	17,620
Related allowance	$ 864	$ 4,820

Loans and Leases and the Allo52

Loans and Leases and the Allowance for Credit Losses - Interest Income Recognized on Impaired Loans (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	$ 749,774	$ 773,478	$ 778,922	$ 763,272
Interest income recognized, Total	6,961	9,552	23,627	20,895
Interest income recognized, Cash basis	4,235	7,430	16,688	14,371
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	175,256	179,327	177,579	161,834
Interest income recognized, Total	1,806	2,327	3,891	4,433
Interest income recognized, Cash basis	1,806	2,327	3,891	4,433
Commercial, Financial, Leasing, etc. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	262,796	242,157	283,783	226,243
Interest income recognized, Total	744	1,017	7,055	2,123
Interest income recognized, Cash basis	744	1,017	7,055	2,123
Residential Builder and Developer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	26,996	53,009	30,832	64,165
Interest income recognized, Total	405	81	488	275
Interest income recognized, Cash basis	405	81	488	275
Other Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	21,500	17,236	19,774	22,130
Interest income recognized, Total	190	1,943	563	2,166
Interest income recognized, Cash basis	190	1,943	563	2,166
Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	96,961	99,939	97,229	101,997
Interest income recognized, Total	1,572	1,835	4,778	4,639
Interest income recognized, Cash basis	570	1,316	2,591	3,011
Residential Limited Documentation [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	101,877	116,191	104,382	120,710
Interest income recognized, Total	1,501	1,539	4,580	4,799
Interest income recognized, Cash basis	378	618	1,648	1,962
Home Equity Lines and Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	41,740	21,952	33,998	20,619
Interest income recognized, Total	368	231	937	656
Interest income recognized, Cash basis	112	66	295	179
Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	18,571	24,429	20,358	26,521
Interest income recognized, Total	303	391	964	1,257
Interest income recognized, Cash basis	19	39	83	136
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	4,077	19,238	10,987	19,053
Interest income recognized, Total	72	188	371	547
Interest income recognized, Cash basis	$ 11	$ 23	$ 74	$ 86

Loans and Leases and the Allo53

Loans and Leases and the Allowance for Credit Losses - Summary of Loan Grades (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	$ 89,646,492	$ 87,489,499
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	21,917,163	20,422,338
Commercial, Financial, Leasing, etc. [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	20,825,301	19,442,183
Commercial, Financial, Leasing, etc. [Member] | Criticized Accrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	860,461	738,238
Commercial, Financial, Leasing, etc. [Member] | Criticized Nonaccrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	231,401	241,917
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	24,619,317	23,532,261
Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	23,540,787	22,697,398
Commercial [Member] | Criticized Accrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	921,003	655,257
Commercial [Member] | Criticized Nonaccrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	157,527	179,606
Residential Builder and Developer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	1,877,244	1,585,673
Residential Builder and Developer [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	1,699,263	1,497,465
Residential Builder and Developer [Member] | Criticized Accrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	157,863	59,779
Residential Builder and Developer [Member] | Criticized Nonaccrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	20,118	28,429
Other Commercial Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	5,582,201	4,079,377
Other Commercial Construction [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	5,405,719	3,834,137
Other Commercial Construction [Member] | Criticized Accrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	155,813	228,877
Other Commercial Construction [Member] | Criticized Nonaccrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	$ 20,669	$ 16,363

Loans and Leases and the Allo54

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	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	$ 93,270		$ 89,960
Allowance for credit losses	800,594		783,750
Allowance for credit losses	976,121	$ 970,496	955,992	$ 933,798	$ 929,987	$ 919,562
Purchased Impaired [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	4,027		4,083
Allocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	897,891		877,793
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	78,230	$ 77,722	78,199	$ 76,732	$ 77,411	$ 75,654
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	55,020		44,752
Allowance for credit losses	273,164		255,615
Commercial, Financial, Leasing, etc. [Member] | Purchased Impaired [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses			37
Commercial, Financial, Leasing, etc. [Member] | Allocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	328,184		300,404
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	16,608		19,175
Allowance for credit losses	340,737		307,000
Commercial Real Estate [Member] | Purchased Impaired [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	2,432		656
Commercial Real Estate [Member] | Allocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	359,777		326,831
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	9,344		12,727
Allowance for credit losses	48,500		57,624
Residential Real Estate [Member] | Purchased Impaired [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	749		1,887
Residential Real Estate [Member] | Allocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	58,593		72,238
Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	12,298		13,306
Allowance for credit losses	138,193		163,511
Consumer Loans [Member] | Purchased Impaired [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	846		1,503
Consumer Loans [Member] | Allocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses	$ 151,337		$ 178,320

Loans and Leases and the Allo55

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	Sep. 30, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	$ 89,646,492	$ 87,489,499
Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	740,003	779,673
Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	88,289,498	85,941,497
Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	616,991	768,329
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	21,917,163	20,422,338
Commercial, Financial, Leasing, etc. [Member] | Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	265,234	272,227
Commercial, Financial, Leasing, etc. [Member] | Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	21,651,134	20,148,209
Commercial, Financial, Leasing, etc. [Member] | Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	795	1,902
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	32,078,762	29,197,311
Commercial Real Estate [Member] | Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	211,730	234,132
Commercial Real Estate [Member] | Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	31,800,749	28,863,130
Commercial Real Estate [Member] | Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	66,283	100,049
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	23,584,420	26,270,103
Residential Real Estate [Member] | Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	198,022	207,949
Residential Real Estate [Member] | Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	22,838,125	25,398,037
Residential Real Estate [Member] | Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	548,273	664,117
Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	12,066,147	11,599,747
Consumer Loans [Member] | Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	65,017	65,365
Consumer Loans [Member] | Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	11,999,490	11,532,121
Consumer Loans [Member] | Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	$ 1,640	$ 2,261

Loans and Leases and the Allo56

Loans and Leases and the Allowance for Credit Losses - Loan Modification Activities that were Considered Troubled Debt Restructurings (Detail) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016USD ($)Modification	Sep. 30, 2015USD ($)Modification	Sep. 30, 2016USD ($)Modification	Sep. 30, 2015USD ($)Modification
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	134	245	569	613
Pre-modification, Recorded investment	$ 93,640	$ 23,691	$ 235,214	$ 139,888
Post-modification, Recorded investment	83,898	23,657	224,499	137,646
Financial effects of modification, Recorded investment	(9,742)	(34)	(10,715)	(2,242)
Financial effects of modification, Interest	$ (599)	$ (557)	$ (1,627)	$ (1,406)
Principal Deferral [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	14	15	40	37
Pre-modification, Recorded investment	$ 12,302	$ 4,230	$ 18,511	$ 47,005
Post-modification, Recorded investment	11,644	4,208	17,802	45,569
Financial effects of modification, Recorded investment	$ (658)	$ (22)	$ (709)	$ (1,436)
Principal Deferral [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	30	36	87	87
Pre-modification, Recorded investment	$ 41,652	$ 7,893	$ 98,956	$ 25,483
Post-modification, Recorded investment	40,183	7,419	98,561	24,331
Financial effects of modification, Recorded investment	$ (1,469)	$ (474)	$ (395)	$ (1,152)
Principal Deferral [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	21	31	46	50
Pre-modification, Recorded investment	$ 4,489	$ 3,540	$ 7,433	$ 4,954
Post-modification, Recorded investment	4,714	3,743	7,945	5,239
Financial effects of modification, Recorded investment	$ 225	$ 203	$ 512	$ 285
Principal Deferral [Member] | Residential Limited Documentation [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	3	1	6	2
Pre-modification, Recorded investment	$ 435	$ 265	$ 711	$ 426
Post-modification, Recorded investment	470	276	803	437
Financial effects of modification, Recorded investment	$ 35	$ 11	$ 92	$ 11
Principal Deferral [Member] | Home Equity Lines and Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	4	4	8	6
Pre-modification, Recorded investment	$ 251	$ 727	$ 655	$ 1,946
Post-modification, Recorded investment	$ 251	$ 727	$ 655	$ 1,946
Principal Deferral [Member] | Automobile [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	10	35	102	133
Pre-modification, Recorded investment	$ 186	$ 316	$ 865	$ 1,234
Post-modification, Recorded investment	$ 186	$ 316	$ 865	$ 1,234
Principal Deferral [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	1	24	56	73
Pre-modification, Recorded investment	$ 26	$ 352	$ 951	$ 1,418
Post-modification, Recorded investment	$ 26	$ 352	$ 951	$ 1,418
Principal Deferral [Member] | Other Commercial Construction [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification		3	1	3
Pre-modification, Recorded investment		$ 296	$ 250	$ 296
Post-modification, Recorded investment		390	$ 250	390
Financial effects of modification, Recorded investment		$ 94		$ 94
Principal Deferral [Member] | Residential Builder and Developer [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification			3	2
Pre-modification, Recorded investment			$ 23,905	$ 10,650
Post-modification, Recorded investment			22,958	10,598
Financial effects of modification, Recorded investment			$ (947)	$ (52)
Combination of Concession Types [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	4	1	13	6
Pre-modification, Recorded investment	$ 2,623	$ 1,156	$ 13,621	$ 3,238
Post-modification, Recorded investment	2,614	1,169	13,546	3,242
Financial effects of modification, Recorded investment	(9)	13	(75)	4
Financial effects of modification, Interest	$ (172)	$ (54)	$ (238)	$ (159)
Combination of Concession Types [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	13	1	25	6
Pre-modification, Recorded investment	$ 27,834	$ 31	$ 49,248	$ 25,075
Post-modification, Recorded investment	19,802	31	39,971	24,884
Financial effects of modification, Recorded investment	(8,032)		(9,277)	(191)
Financial effects of modification, Interest	$ (6)	$ (6)	$ (6)	$ (245)
Combination of Concession Types [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	9	10	27	22
Pre-modification, Recorded investment	$ 1,149	$ 1,296	$ 4,513	$ 2,551
Post-modification, Recorded investment	1,214	1,380	4,705	2,795
Financial effects of modification, Recorded investment	65	84	192	244
Financial effects of modification, Interest	$ (120)	$ (178)	$ (120)	$ (356)
Combination of Concession Types [Member] | Residential Limited Documentation [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	3	4	8	7
Pre-modification, Recorded investment	$ 392	$ 605	$ 1,704	$ 1,239
Post-modification, Recorded investment	493	662	1,872	1,298
Financial effects of modification, Recorded investment	101	57	168	59
Financial effects of modification, Interest	$ (123)	$ (91)	$ (462)	$ (121)
Combination of Concession Types [Member] | Home Equity Lines and Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	22	22	76	41
Pre-modification, Recorded investment	$ 2,301	$ 2,003	$ 8,534	$ 3,555
Post-modification, Recorded investment	2,301	2,003	8,534	3,555
Financial effects of modification, Interest	$ (178)	$ (199)	$ (741)	$ (424)
Combination of Concession Types [Member] | Automobile [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification		25	8	42
Pre-modification, Recorded investment		$ 471	$ 85	$ 693
Post-modification, Recorded investment		471	85	693
Financial effects of modification, Interest		$ (17)	$ (3)	$ (28)
Combination of Concession Types [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification		12	17	35
Pre-modification, Recorded investment		$ 117	$ 196	$ 384
Post-modification, Recorded investment		117	196	384
Financial effects of modification, Interest		$ (12)	$ (32)	$ (44)
Combination of Concession Types [Member] | Other Commercial Construction [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification			1
Pre-modification, Recorded investment			$ 124
Post-modification, Recorded investment			$ 124
Other [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification			1
Pre-modification, Recorded investment			$ 4,723
Post-modification, Recorded investment			4,447
Financial effects of modification, Recorded investment			$ (276)
Other [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification				2
Pre-modification, Recorded investment				$ 8,991
Post-modification, Recorded investment				8,883
Financial effects of modification, Recorded investment				$ (108)
Other [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification		1		1
Pre-modification, Recorded investment		$ 267		$ 267
Post-modification, Recorded investment		$ 267		$ 267
Other [Member] | Automobile [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification		15	38	38
Pre-modification, Recorded investment		$ 93	$ 55	$ 134
Post-modification, Recorded investment		$ 93	$ 55	$ 134
Other [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification		5	5	12
Pre-modification, Recorded investment		$ 33	$ 45	$ 113
Post-modification, Recorded investment		$ 33	$ 45	$ 113
Interest Rate Reduction [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification			1
Pre-modification, Recorded investment			$ 129
Post-modification, Recorded investment			129
Financial effects of modification, Interest			$ (25)
Interest Rate Reduction [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification				1
Pre-modification, Recorded investment				$ 99
Post-modification, Recorded investment				99
Financial effects of modification, Interest				$ (19)
Interest Rate Reduction [Member] | Automobile [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification				7
Pre-modification, Recorded investment				$ 137
Post-modification, Recorded investment				137
Financial effects of modification, Interest				$ (10)

Borrowings - Additional Informa

Borrowings - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Debt Instruments [Abstract]
Junior subordinated debentures	$ 516
Trust preferred capital securities	0.00%
Debt Maturity, Start Year	Jan. 1, 2027
Debt Maturity, End Year	Dec. 31, 2033
Agreements to repurchase securities	$ 1,800	$ 1,900
Collateral posted	$ 1,900	$ 2,000

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail) - USD ($)	3 Months Ended	9 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Oct. 28, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Preferred stock, shares authorized		1,000,000		1,000,000
Preferred stock, par value		$ 1		$ 1
Series F Fixed-to-Floating Non-cumulative Perpetual Preferred Stock [Member] | Subsequent Event
Class of Stock [Line Items]
Preferred stock, par value			$ 1
Preferred stock, shares issued			50,000
Preferred Stock, Liquidation Preference, Value			$ 10,000
Series D Fixed Rate Non-cumulative Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares issued		50,000		50,000
Preferred stock dividend rate		6.875%
Preferred stock, liquidation preference per share		$ 10,000		$ 10,000
Series D Fixed Rate Non-cumulative Perpetual Preferred Stock [Member] | Subsequent Event
Class of Stock [Line Items]
Stock expects to be redeemed	50,000
Preferred stock, liquidation preference per share	$ 10,000
Scenario Forecast | Series F Fixed-to-Floating Non-cumulative Perpetual Preferred Stock [Member] | Subsequent Event
Class of Stock [Line Items]
Preferred stock dividend rate	5.125%
Receivable dividends rate	3.52%
Date of change in the dividend rate	Nov. 1, 2026
Preferred Stock, Redemption Feature, Redemption Term	90 days
Warrant [Member] | Assumed In Acquisition [Member]
Class of Stock [Line Items]
Exercise price of each class of warrants or rights outstanding		$ 518.96		$ 518.96
Warrant to purchase common stock		95,383		95,383

Shareholders' Equity - Issued a

Shareholders' Equity - Issued and Outstanding Preferred Stock (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Carrying value	$ 1,231,500	$ 1,231,500
Series A Fixed Rate Cumulative Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares issued	230,000	230,000
Preferred stock, shares outstanding	230,000	230,000
Carrying value	$ 230,000	$ 230,000
Series C Fixed Rate Cumulative Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares issued	151,500	151,500
Preferred stock, shares outstanding	151,500	151,500
Carrying value	$ 151,500	$ 151,500
Series D Fixed Rate Non-cumulative Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares issued	50,000	50,000
Preferred stock, shares outstanding	50,000	50,000
Carrying value	$ 500,000	$ 500,000
Series E Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares issued	350,000	350,000
Preferred stock, shares outstanding	350,000	350,000
Carrying value	$ 350,000	$ 350,000

Shareholders' Equity - Issued60

Shareholders' Equity - Issued and Outstanding Preferred Stock (Parenthetical) (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Series A Fixed Rate Cumulative Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, liquidation preference per share	$ 1,000	$ 1,000
Preferred stock dividend rate	6.375%
Exercise price of each class of warrants or rights outstanding	$ 73.86
Warrants and rights outstanding	713,855	719,175
Warrants, year of expiration	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
Series D Fixed Rate Non-cumulative Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, liquidation preference per share	$ 10,000	10,000
Preferred stock dividend rate	6.875%
Preferred shares redemption date	Jun. 15, 2016
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%
Preferred shares redemption date	Feb. 15, 2024
Preferred Stock, Redemption Feature, Redemption Term	90 days
Date of change in the dividend rate	Feb. 14, 2024
London Interbank offered rate plus basis points	3.61%

Pension Plans and Other Postr61

Pension Plans and Other Postretirement Benefits - Net Periodic Defined Benefit Cost for Defined Benefit Plans (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 6,259	$ 5,916	$ 18,778	$ 17,748
Interest cost on projected benefit obligation	20,853	17,754	62,558	53,261
Expected return on plan assets	(27,118)	(23,527)	(81,355)	(70,578)
Amortization of prior service credit	(807)	(1,501)	(2,421)	(4,504)
Amortization of net actuarial loss	7,536	11,207	22,609	33,619
Net periodic benefit cost	6,723	9,849	20,169	29,546
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	399	188	1,197	562
Interest cost on projected benefit obligation	1,242	651	3,728	1,953
Amortization of prior service credit	(339)	(340)	(1,019)	(1,019)
Amortization of net actuarial loss	15	26	45	79
Net periodic benefit cost	$ 1,317	$ 525	$ 3,951	$ 1,575

Pension Plans and Other Postr62

Pension Plans and Other Postretirement Benefits - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Compensation And Retirement Disclosure [Abstract]
Defined contribution pension and retirement savings plans total expense	$ 14,783,000	$ 14,281,000	$ 47,747,000	$ 44,377,000

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		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income available to common shareholders:
Net income	$ 349,984	$ 280,401	$ 984,543	$ 808,702
Less: Preferred stock dividends	(20,318)	(20,318)	(60,953)	(60,953)
Net income available to common equity	329,666	260,083	923,590	747,749
Less: Income attributable to unvested stock-based compensation awards	(2,674)	(2,746)	(7,920)	(8,122)
Net income available to common shareholders	$ 326,992	$ 257,337	$ 915,670	$ 739,627
Weighted-average shares outstanding:
Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards	156,767	134,049	158,710	133,805
Less: Unvested stock-based compensation awards	(1,274)	(1,419)	(1,374)	(1,458)
Weighted-average shares outstanding	155,493	132,630	157,336	132,347
Basic earnings per common share	$ 2.10	$ 1.94	$ 5.82	$ 5.59

Earnings Per Common Share - C64

Earnings Per Common Share - Computations of Diluted Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Net income available to common equity	$ 329,666	$ 260,083	$ 923,590	$ 747,749
Less: Income attributable to unvested stock-based compensation awards	(2,668)	(2,737)	(7,904)	(8,093)
Net income available to common shareholders	$ 326,998	$ 257,346	$ 915,686	$ 739,656
Adjusted weighted-average shares outstanding:
Common and unvested stock-based compensation awards	156,767	134,049	158,710	133,805
Less: Unvested stock-based compensation awards	(1,274)	(1,419)	(1,374)	(1,458)
Plus: Incremental shares from assumed conversion of stock-based compensation awards and warrants to purchase common stock	533	746	507	742
Adjusted weighted-average shares outstanding	156,026	133,376	157,843	133,089
Diluted earnings per common share	$ 2.10	$ 1.93	$ 5.80	$ 5.56

Earnings Per Common Share - Add

Earnings Per Common Share - Additional Information (Detail) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Antidilutive securities excluded from computation of earnings per share	2	1.5	2.5	1.9

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		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, before tax			$ (414,545)	$ (297,843)
Unrealized holding gains (losses), before tax			235,666	(1,440)
Foreign currency translation adjustment, before tax			(2,836)	(735)
Gains on cash flow hedges, before tax				1,453
Total other comprehensive income (loss) before reclassifications, before tax			232,830	(722)
Accretion of unrealized holding losses on held-to-maturity (“HTM”) securities, before tax			2,998	2,417
Gains (losses) realized in net income, before tax			(28,748)	108
Accretion of net gain on terminated cash flow hedges, before tax			(116)	(102)
Amortization of prior service credit, before tax			(3,440)	(5,523)
Amortization of actuarial losses, before tax			22,654	33,698
Total reclassifications, before tax			(6,652)	30,598
Total gain (loss) during the period, before tax			226,178	29,876
Ending balance, before tax	$ (188,367)	$ (267,967)	(188,367)	(267,967)
Beginning balance, tax			162,918	116,849
Unrealized holding gains (losses), tax			(92,714)	952
Foreign currency translation adjustment, tax			989	214
Gains on cash flow hedges, tax				(568)
Total other comprehensive income (loss) before reclassifications, tax			(91,725)	598
Accretion of unrealized holding losses on held-to-maturity (“HTM”) securities, tax			(1,180)	(944)
Gains (losses) realized in net income, tax			11,309	(40)
Accretion of net gain on terminated cash flow hedges, tax			46	40
Amortization of prior service credit, tax			1,354	2,359
Amortization of actuarial losses, tax			(8,914)	(14,368)
Total reclassifications, tax			2,615	(12,953)
Total gain (loss) during the period, tax			(89,110)	(12,355)
Ending balance, tax	73,808	104,494	73,808	104,494
Beginning balance			(251,627)	(180,994)
Unrealized holding gains (losses), net of tax			142,952	(488)
Foreign currency translation adjustment, net of tax	(229)	(3)	(1,847)	(521)
Gains on cash flow hedges, net of tax				885
Total other comprehensive income (loss) before reclassifications, net of tax			141,105	(124)
Accretion of unrealized holding losses on held-to-maturity ("HTM") securities, net of tax			1,818	1,473
Gains (losses) realized in net income, net of tax			(17,439)	68
Accretion of net gain on terminated cash flow hedges, net of tax			(70)	(62)
Amortization of prior service credit, net of tax			(2,086)	(3,164)
Amortization of actuarial losses, net of tax			13,740	19,330
Total reclassifications, net of tax			(4,037)	17,645
Total other comprehensive income (loss)	(13,538)	54,029	137,068	17,521
Ending balance	(114,559)	(163,473)	(114,559)	(163,473)
Investment securities With OTTI [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, before tax			16,359	7,438
Unrealized holding gains (losses), before tax			1,228	9,699
Total other comprehensive income (loss) before reclassifications, before tax			1,228	9,699
Total gain (loss) during the period, before tax			1,228	9,699
Ending balance, before tax	17,587	17,137	17,587	17,137
Investment securities All Other [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, before tax			62,849	201,828
Unrealized holding gains (losses), before tax			234,438	(11,139)
Total other comprehensive income (loss) before reclassifications, before tax			234,438	(11,139)
Accretion of unrealized holding losses on held-to-maturity (“HTM”) securities, before tax			2,998	2,417
Gains (losses) realized in net income, before tax			(28,748)	108
Total reclassifications, before tax			(25,750)	2,525
Total gain (loss) during the period, before tax			208,688	(8,614)
Ending balance, before tax	271,537	193,214	271,537	193,214
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, before tax			(489,660)	(503,027)
Amortization of prior service credit, before tax			(3,440)	(5,523)
Amortization of actuarial losses, before tax			22,654	33,698
Total reclassifications, before tax			19,214	28,175
Total gain (loss) during the period, before tax			19,214	28,175
Ending balance, before tax	(470,446)	(474,852)	(470,446)	(474,852)
Total other comprehensive income (loss)			11,654
Other [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, before tax			(4,093)	(4,082)
Foreign currency translation adjustment, before tax			(2,836)	(735)
Gains on cash flow hedges, before tax				1,453
Total other comprehensive income (loss) before reclassifications, before tax			(2,836)	718
Accretion of net gain on terminated cash flow hedges, before tax			(116)	(102)
Total reclassifications, before tax			(116)	(102)
Total gain (loss) during the period, before tax			(2,952)	616
Ending balance, before tax	$ (7,045)	$ (3,466)	$ (7,045)	$ (3,466)

Comprehensive Income - Accumula

Comprehensive Income - Accumulated Other Comprehensive Income (Loss), Net (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			$ 16,173,289	$ 12,335,896
Net gain (loss) during period	$ (13,538)	$ 54,029	137,068	17,521
Ending balance	16,340,976	12,921,934	16,340,976	12,921,934
Investment securities With OTTI [Member] | Investment Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			9,921
Net gain (loss) during period			745
Ending balance	10,666		10,666
Investment securities All Other [Member] | Investment Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			38,166
Net gain (loss) during period			126,586
Ending balance	164,752		164,752
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(296,979)
Net gain (loss) during period			11,654
Ending balance	(285,325)		(285,325)
Accumulated Other Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(2,735)
Net gain (loss) during period			(1,917)
Ending balance	(4,652)		(4,652)
Accumulated Other Comprehensive Income (Loss), Net [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(251,627)	(180,994)
Net gain (loss) during period			137,068
Ending balance	$ (114,559)	$ (163,473)	$ (114,559)	$ (163,473)

Derivative Financial Instrume68

Derivative Financial Instruments - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
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	$ 38,000,000		$ 38,000,000		$ 18,000,000
Aggregate fair value of derivative financial instruments in a liability position	85,000,000		85,000,000		59,000,000
Net liability positions with counterparties	81,000,000		81,000,000		55,000,000
Aggregate fair value of derivative financial instruments in asset position	15,000,000		15,000,000		23,000,000
Net asset positions with counterparties	11,000,000		11,000,000		19,000,000
Counterparties posted collateral relating to positions	11,000,000		11,000,000		22,000,000
Counterparties [Member]
Derivative [Line Items]
Post collateral requirements relating to positions	79,000,000		79,000,000		52,000,000
Clearinghouse Credit Facilities [Member]
Derivative [Line Items]
Post collateral requirements relating to positions	265,000,000		265,000,000		99,000,000
Aggregate fair value of derivative financial instruments in a net liability position	177,000,000		177,000,000		50,000,000
Interest Rate Swap Agreements [Member]
Derivative [Line Items]
Increase in net interest income due to interest rate swap agreements	9,000,000	$ 11,000,000	30,000,000	$ 33,000,000
Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amounts of derivative contracts entered into for trading account purposes	21,200,000,000		21,200,000,000		18,400,000,000
Foreign Currency and Other Option and Futures Contracts [Member]
Derivative [Line Items]
Notional amounts of derivative contracts entered into for trading account purposes	891,000,000		891,000,000		$ 1,600,000,000
Credit Risk Derivative [Member]
Derivative [Line Items]
Aggregate fair value of derivative financial instruments in a net liability position	19,000,000		19,000,000
Fair value of collateral already posted for derivative financial instruments	15,000,000		15,000,000
Fair value of additional collateral to be posted for derivative financial instruments	$ 4,000,000		$ 4,000,000

Derivative Financial Instrume69

Derivative Financial Instruments - Information about Interest Rate Swap Agreements (Detail) - Fixed Rate Long-Term Borrowings [Member] - Fair Value Hedges [Member] - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Derivative [Line Items]
Notional Amount	$ 1,400,000,000	$ 1,400,000,000
Average Maturity (in years)	10 months 24 days	1 year 8 months 12 days
Weighted-Average Rate, Fixed	4.42%	4.42%
Weighted-Average Rate, Variable	1.79%	1.39%

Derivative Financial Instrume70

Derivative Financial Instruments - Information about Fair Values of Derivative Instruments in Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Asset derivatives, Fair value	$ 405,464	$ 268,637
Liability derivatives, Fair value	305,147	162,650
Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives, Fair value	384,022	222,901
Liability derivatives, Fair value	301,201	161,994
Fair Value Hedges [Member] | Derivatives Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives, Fair value	21,442	45,736
Liability derivatives, Fair value	3,946	656
Interest Rate Swap Agreements [Member] | Fair Value Hedges [Member] | Derivatives Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives, Fair value	21,060	43,892
Commitments to Sell Real Estate Loans [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives, Fair value	626	533
Liability derivatives, Fair value	8,437	846
Commitments to Sell Real Estate Loans [Member] | Fair Value Hedges [Member] | Derivatives Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives, Fair value	382	1,844
Liability derivatives, Fair value	3,946	656
Mortgage-Related Commitments to Originate Real Estate Loans for Sale [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives, Fair value	29,851	10,282
Liability derivatives, Fair value	51	403
Interest Rate Contracts [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives, Fair value	346,453	203,517
Liability derivatives, Fair value	286,298	153,723
Foreign Exchange and Other Option and Futures Contracts [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives, Fair value	7,092	8,569
Liability derivatives, Fair value	$ 6,415	$ 7,022

Derivative Financial Instrume71

Derivative Financial Instruments - Information about Fair Values of Derivative Instruments in Consolidated Statement of Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives not designated as hedging instruments, Derivatives	$ 6,568	$ 6,733	$ 16,993	$ 13,575
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	(12,588)	(2,719)	(22,832)	(12,469)
Derivatives in fair value hedging relationships, Hedged item	12,587	2,382	21,603	11,495
Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives not designated as hedging instruments, Derivatives	4,822	4,120	11,578	6,552
Foreign Exchange and Other Option and Futures Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives not designated as hedging instruments, Derivatives	$ 1,746	$ 2,613	$ 5,415	$ 7,023

Variable Interest Entities an72

Variable Interest Entities and Asset Securitizations - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Variable Interest Entity Disclosure [Abstract]
Carrying value of loans in the Securitization trusts					$ 81,000,000
Combined outstanding principal amount of mortgage-backed securities issued by qualified special purpose trust held by unrelated parties					13,000,000
Other assets for its "investment" in the common securities recognized by the company of various trusts	$ 24,000,000		$ 24,000,000		24,000,000
Total assets of partnerships in which the company invested	1,100,000,000		1,100,000,000		1,100,000,000
Maximum exposure to loss of investments in real estate partnerships	287,000,000		287,000,000		295,000,000
Unfunded commitments included in company's maximum exposure to loss of investments in real estate partnerships	82,000,000		82,000,000		$ 78,000,000
Investments amortized to income tax expense	13,000,000	$ 10,000,000	34,000,000	$ 31,000,000
Federal tax credits and other federal tax benefits recognized	$ 18,000,000	$ 15,000,000	$ 46,000,000	$ 44,000,000

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016USD ($)Source	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)Source	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Number of independent pricing sources used to value privately issued mortgage-backed securities valued with internal modeling | Source	2		2
Securities issued by financial institutions and other entities backed by trust preferred securities at cost					$ 28
Fair value of securities issued by financial institutions and other entities backed by trust preferred securities					47
Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Change in fair value of nonrecurring fair value measured loans for charge-offs and impairment reserves	$ 20	$ 11	$ 42	$ 53
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	249	177	249	177	210
Assets taken in foreclosure of defaulted loans measured at fair value on a nonrecurring basis	53	15	53	15
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	144	106	144	106	106
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	$ 105	$ 71	$ 105	$ 71	$ 104
Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount margin over LIBOR			4.00%
Discount rates for fair value estimations			15.00%
Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount margin over LIBOR			10.00%
Discount rates for fair value estimations			92.00%
Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount margin over LIBOR			8.00%

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Estimated Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets	$ 488,588	$ 273,783
Investment securities	11,862,567	12,242,671
U.S. Treasury and Federal Agencies [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	726,401	299,997
Obligations of States and Political Subdivisions [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	5,015	6,028
Government Issued or Guaranteed [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	10,930,662	11,686,628
Collateralized Debt Obligations [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities		47,393
Other Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	118,226	118,880
Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	82,212	83,671
Fair Value Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets	488,588	273,783
Investment securities	11,862,567	12,242,671
Real estate loans held for sale	704,984	392,036
Other assets	51,919	56,551
Total assets	13,108,058	12,965,041
Trading account liabilities	292,713	160,745
Other liabilities	12,434	1,905
Total liabilities	305,147	162,650
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	726,401	299,997
Fair Value Measurements, Recurring [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	5,015	6,028
Fair Value Measurements, Recurring [Member] | Government Issued or Guaranteed [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	10,930,662	11,686,628
Fair Value Measurements, Recurring [Member] | Privately Issued Mortgage-Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	51	74
Fair Value Measurements, Recurring [Member] | Collateralized Debt Obligations [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities		47,393
Fair Value Measurements, Recurring [Member] | Other Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	118,226	118,880
Fair Value Measurements, Recurring [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	82,212	83,671
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	50,699	56,763
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets	50,699	56,763
Investment securities	62,546	65,178
Total assets	113,245	121,941
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value Measurements, Recurring [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	62,546	65,178
Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets	437,889	217,020
Trading account liabilities	292,713	160,745
Significant Observable Inputs (Level 2) [Member] | Fair Value Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading account assets	437,889	217,020
Investment securities	11,799,970	12,130,026
Real estate loans held for sale	704,984	392,036
Other assets	22,068	46,269
Total assets	12,964,911	12,785,351
Trading account liabilities	292,713	160,745
Other liabilities	12,383	1,502
Total liabilities	305,096	162,247
Significant Observable Inputs (Level 2) [Member] | 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	726,401	299,997
Significant Observable Inputs (Level 2) [Member] | 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	5,015	6,028
Significant Observable Inputs (Level 2) [Member] | 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	10,930,662	11,686,628
Significant Observable Inputs (Level 2) [Member] | Fair Value Measurements, Recurring [Member] | Other Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	118,226	118,880
Significant Observable Inputs (Level 2) [Member] | Fair Value Measurements, Recurring [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	19,666	18,493
Significant Unobservable Inputs (Level 3) [Member] | Fair Value Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities	51	47,467
Other assets	29,851	10,282
Total assets	29,902	57,749
Other liabilities	51	403
Total liabilities	51	403
Significant Unobservable Inputs (Level 3) [Member] | 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	$ 51	74
Significant Unobservable Inputs (Level 3) [Member] | Fair Value Measurements, Recurring [Member] | Collateralized Debt Obligations [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities		$ 47,393

Fair Value Measurements - 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		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Privately Issued [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 57	$ 88	$ 74	$ 103
Total gains (losses) realized/unrealized:
Settlements	(6)	(6)	(23)	(21)
Ending Balance	51	82	51	82
Collateralized Debt Obligations [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	43,305	50,483	47,393	50,316
Total gains (losses) realized/unrealized:
Included in earnings	28,475		28,475
Included in other comprehensive income	(15,050)	(472)	(18,268)	5,153
Sales	(56,730)		(56,730)
Settlements		(135)	(870)	(5,593)
Ending Balance		49,876		49,876
Other Assets and Other Liabilities [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	21,383	11,206	9,879	17,347
Total gains (losses) realized/unrealized:
Included in earnings	45,534	21,709	104,862	67,611
Transfers in and/or out of Level 3	(37,117)	(15,268)	(84,941)	(67,311)
Ending Balance	29,800	17,647	29,800	17,647
Changes in unrealized gains included in earnings related to assets still held at end of period	$ 27,663	$ 15,488	$ 29,288	$ 15,965

Fair Value Measurements - Quant

Fair Value Measurements - Quantitative Information Related to Significant Unobservable Inputs (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Privately Issued [Member] | Two Independent Pricing Quotes [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Recurring fair value measurements for certain Level 3 Assets and Liabilities	$ 51
Privately Issued [Member] | Two Independent Pricing Quotes [Member] | Fair Value Measurements, Recurring [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		$ 74
Collateralized Debt Obligations [Member] | Discounted Cash Flows [Member] | Fair Value Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Recurring fair value measurements for certain Level 3 Assets and Liabilities		$ 47,393
Loss severity		100.00%
Collateralized Debt Obligations [Member] | Discounted Cash Flows [Member] | Minimum [Member] | Fair Value Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Probability of default		10.00%
Collateralized Debt Obligations [Member] | Discounted Cash Flows [Member] | Maximum [Member] | Fair Value Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Probability of default		56.00%
Collateralized Debt Obligations [Member] | Discounted Cash Flows [Member] | Weighted Average [Member] | Fair Value Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Probability of default		31.00%
Other Assets and Other Liabilities [Member] | Discounted Cash Flows [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Recurring fair value measurements for certain Level 3 Assets and Liabilities	$ 29,800
Other Assets and Other Liabilities [Member] | Discounted Cash Flows [Member] | Fair Value Measurements, Recurring [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		$ 9,879
Other Assets and Other Liabilities [Member] | Discounted Cash Flows [Member] | Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Commitment expirations	0.00%
Other Assets and Other Liabilities [Member] | Discounted Cash Flows [Member] | Minimum [Member] | Fair Value Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Commitment expirations		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	92.00%
Other Assets and Other Liabilities [Member] | Discounted Cash Flows [Member] | Maximum [Member] | Fair Value Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Commitment expirations		60.00%
Other Assets and Other Liabilities [Member] | Discounted Cash Flows [Member] | Weighted Average [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Commitment expirations	26.00%
Other Assets and Other Liabilities [Member] | Discounted Cash Flows [Member] | Weighted Average [Member] | Fair Value Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Commitment expirations		39.00%

Fair Value Measurements - Carry

Fair Value Measurements - Carrying Amounts and Estimated Fair Value for Financial Instrument Assets (Liabilities) (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Financial assets:
Cash and cash equivalents	$ 1,332,202		$ 1,368,040	$ 1,249,704		$ 1,373,357
Interest-bearing deposits at banks	10,777,636		7,594,350
Trading account assets	488,588		273,783
Investment securities	14,733,574		15,656,439
Loans and leases:
Allowance for credit losses	(976,121)	$ (970,496)	(955,992)	$ (933,798)	$ (929,987)	$ (919,562)
Loans and leases, net	88,670,371		86,533,507
Financial liabilities:
Noninterest-bearing deposits	(33,127,627)		(29,110,635)
Time deposits	(11,721,005)		(13,110,392)
Deposits at Cayman Islands office	(223,183)		(170,170)
Short-term borrowings	(213,846)		(150,546)
Long-term borrowings	(10,211,160)		(10,653,858)
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets:
Cash and cash equivalents	1,258,882		1,276,678
Trading account assets	50,699		56,763
Investment securities	62,546		65,178
Significant Observable Inputs (Level 2) [Member]
Financial assets:
Cash and cash equivalents	73,320		91,362
Interest-bearing deposits at banks	10,777,636		7,594,350
Trading account assets	437,889		217,020
Investment securities	14,591,141		15,406,404
Loans and leases:
Commercial real estate loans	290,347		38,774
Residential real estate loans	4,607,044		4,727,816
Loans and leases, net	4,897,391		4,766,590
Accrued interest receivable	311,414		306,496
Financial liabilities:
Noninterest-bearing deposits	(33,127,627)		(29,110,635)
Savings and interest-checking deposits	(53,065,030)		(49,566,644)
Time deposits	(11,829,119)		(13,135,042)
Deposits at Cayman Islands office	(223,183)		(170,170)
Short-term borrowings	(213,846)		(2,132,182)
Long-term borrowings	(10,277,155)		(10,639,556)
Accrued interest payable	(76,230)		(85,145)
Trading account liabilities	(292,713)		(160,745)
Other financial instruments:
Commitments to sell real estate loans	(11,375)		875
Interest rate swap agreements used for interest rate risk management	21,060		43,892
Significant Unobservable Inputs (Level 3) [Member]
Financial assets:
Investment securities	126,034		189,295
Loans and leases:
Commercial loans and leases	21,563,190		20,146,201
Commercial real estate loans	31,653,994		29,005,470
Residential real estate loans	19,173,949		21,539,955
Consumer loans	12,009,873		11,550,270
Loans and leases, net	84,401,006		82,241,896
Other financial instruments:
Commitments to originate real estate loans for sale	29,800		9,879
Other credit-related commitments	(124,499)		(122,334)
Carrying Amount [Member]
Financial assets:
Cash and cash equivalents	1,332,202		1,368,040
Interest-bearing deposits at banks	10,777,636		7,594,350
Trading account assets	488,588		273,783
Investment securities	14,733,574		15,656,439
Loans and leases:
Commercial loans and leases	21,917,163		20,422,338
Commercial real estate loans	32,078,762		29,197,311
Residential real estate loans	23,584,420		26,270,103
Consumer loans	12,066,147		11,599,747
Allowance for credit losses	(976,121)		(955,992)
Loans and leases, net	88,670,371		86,533,507
Accrued interest receivable	311,414		306,496
Financial liabilities:
Noninterest-bearing deposits	(33,127,627)		(29,110,635)
Savings and interest-checking deposits	(53,065,030)		(49,566,644)
Time deposits	(11,721,005)		(13,110,392)
Deposits at Cayman Islands office	(223,183)		(170,170)
Short-term borrowings	(213,846)		(2,132,182)
Long-term borrowings	(10,211,160)		(10,653,858)
Accrued interest payable	(76,230)		(85,145)
Trading account liabilities	(292,713)		(160,745)
Other financial instruments:
Commitments to originate real estate loans for sale	29,800		9,879
Commitments to sell real estate loans	(11,375)		875
Other credit-related commitments	(124,499)		(122,334)
Interest rate swap agreements used for interest rate risk management	21,060		43,892
Estimate Fair Value [Member]
Financial assets:
Cash and cash equivalents	1,332,202		1,368,040
Interest-bearing deposits at banks	10,777,636		7,594,350
Trading account assets	488,588		273,783
Investment securities	14,779,721		15,660,877
Loans and leases:
Commercial loans and leases	21,563,190		20,146,201
Commercial real estate loans	31,944,341		29,044,244
Residential real estate loans	23,780,993		26,267,771
Consumer loans	12,009,873		11,550,270
Loans and leases, net	89,298,397		87,008,486
Accrued interest receivable	311,414		306,496
Financial liabilities:
Noninterest-bearing deposits	(33,127,627)		(29,110,635)
Savings and interest-checking deposits	(53,065,030)		(49,566,644)
Time deposits	(11,829,119)		(13,135,042)
Deposits at Cayman Islands office	(223,183)		(170,170)
Short-term borrowings	(213,846)		(2,132,182)
Long-term borrowings	(10,277,155)		(10,639,556)
Accrued interest payable	(76,230)		(85,145)
Trading account liabilities	(292,713)		(160,745)
Other financial instruments:
Commitments to originate real estate loans for sale	29,800		9,879
Commitments to sell real estate loans	(11,375)		875
Other credit-related commitments	(124,499)		(122,334)
Interest rate swap agreements used for interest rate risk management	$ 21,060		$ 43,892

Commitments and Contingencies -

Commitments and Contingencies - Company's Significant Commitments (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Commitments to extend credit
Home equity lines of credit	$ 5,525,814	$ 5,631,680
Commercial real estate loans to be sold	403,411	57,597
Other commercial real estate	6,365,999	5,949,933
Residential real estate loans to be sold	635,661	488,621
Other residential real estate	297,191	212,619
Commercial and other	12,219,005	11,802,850
Standby letters of credit	3,283,270	3,330,013
Commercial letters of credit	50,109	55,559
Financial guarantees and indemnification contracts	3,147,784	2,794,322
Commitments to sell real estate loans	$ 1,538,900	$ 782,885

Commitments and Contingencies79

Commitments and Contingencies - Additional Information (Detail) - USD ($)	May 12, 2016	Sep. 30, 2016	Dec. 31, 2015
Loss Contingencies [Line Items]
Maximum credit risk for recourse associated with loans sold under Federal National Mortgage Association Delegated Underwriting and Servicing program		$ 2,700,000,000	$ 2,500,000,000
Payment of litigation settlement expense	$ 64,000,000
Minimum [Member]
Loss Contingencies [Line Items]
Range of reasonably possible losses		0
Maximum [Member]
Loss Contingencies [Line Items]
Range of reasonably possible losses		$ 40,000,000

Segment Information - Informati

Segment Information - Information about Company's Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Net income (loss)	$ 349,984	$ 280,401	$ 984,543	$ 808,702
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	1,349,690	1,132,526	3,954,660	3,412,472
Business Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)	21,422	23,995	69,617	74,160
Business Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	116,513	112,650	344,562	332,341
Business Banking [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total revenues	1,086	1,167	3,274	3,334
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)	102,796	108,422	309,515	312,926
Commercial Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	268,683	270,554	787,781	774,392
Commercial Banking [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total revenues	950	1,097	2,917	3,281
Commercial Real Estate [Member]
Segment Reporting Information [Line Items]
Net income (loss)	90,065	85,312	254,682	250,501
Commercial Real Estate [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	205,562	181,478	575,117	535,909
Commercial Real Estate [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total revenues	463	469	1,299	978
Discretionary Portfolio [Member]
Segment Reporting Information [Line Items]
Net income (loss)	50,773	5,113	151,522	21,823
Discretionary Portfolio [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	114,391	13,773	324,195	49,724
Discretionary Portfolio [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total revenues	(14,795)	(5,365)	(43,726)	(16,184)
Residential Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)	22,924	21,150	59,981	75,462
Residential Mortgage Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	108,576	99,518	309,393	310,843
Residential Mortgage Banking [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total revenues	22,051	12,918	62,955	36,741
Retail Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)	69,506	64,721	204,291	202,415
Retail Banking [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	353,016	308,520	1,037,727	914,484
Retail Banking [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total revenues	3,052	3,292	9,198	9,688
All Other [Member]
Segment Reporting Information [Line Items]
Net income (loss)	(7,502)	(28,312)	(65,065)	(128,585)
All Other [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	182,949	146,033	575,885	494,779
All Other [Member] | Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Total revenues	$ (12,807)	$ (13,578)	$ (35,917)	$ (37,838)

Segment Information - Summary o

Segment Information - Summary of Segment Information (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015
Segment Reporting Information [Line Items]
Average Assets	$ 123,897	$ 101,780	$ 97,345
Business Banking [Member]
Segment Reporting Information [Line Items]
Average Assets	5,442	5,339	5,321
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Average Assets	25,363	24,143	24,041
Commercial Real Estate [Member]
Segment Reporting Information [Line Items]
Average Assets	20,571	18,827	18,632
Discretionary Portfolio [Member]
Segment Reporting Information [Line Items]
Average Assets	41,253	26,648	23,153
Residential Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Average Assets	2,578	2,918	3,007
Retail Banking [Member]
Segment Reporting Information [Line Items]
Average Assets	11,739	11,035	10,912
All Other [Member]
Segment Reporting Information [Line Items]
Average Assets	$ 16,951	$ 12,870	$ 12,279

Segment Information - Summary82

Segment Information - Summary of Segment Information (Parenthetical) (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting [Abstract]
Taxable-equivalent adjustment	$ 6,725,000	$ 6,248,000	$ 19,579,000	$ 18,106,000

Relationship with Bayview Len83

Relationship with Bayview Lending Group LLC and Bayview Financial Holdings, L.P. - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Bayview Lending Group [Member]
Schedule of Equity Method Investments [Line Items]
Minority interest in Bayview Lending Group LLC	20.00%		20.00%
Carrying value of minority interest investment in Bayview Lending Group LLC	$ 15		$ 15
Bayview Lending Group and Bayview Financial [Member]
Schedule of Equity Method Investments [Line Items]
Outstanding principal balances of mortgage servicing rights	3,700		3,700		$ 4,100
Revenues from servicing	5	$ 6	15	$ 17
Bayview Financial [Member]
Schedule of Equity Method Investments [Line Items]
Outstanding principal balances of residential mortgage loans from Bayview Financial	32,100		32,100		37,700
Revenues from sub-servicing	25	$ 26	73	$ 91
Investment securities in held-to-maturity portfolio securitized by Bayview Financial	$ 163		$ 163		$ 181

Sale of Trust Accounts - Additi

Sale of Trust Accounts - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended
	Apr. 30, 2015	Jun. 30, 2015	Mar. 31, 2015
Discontinued Operations And Disposal Groups [Abstract]
Gain on sale of business net of tax	$ 23,000,000
Gain on sale of business before tax	45,000,000
Goodwill recorded	$ 11,000,000
Revenue on sale of business		$ 0	$ 9,000,000