M&T Bank (MTB) 10-Q 30 Oct 15 2015 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2015	Oct. 23, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2015
Document Fiscal Year Focus	2,015
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		133,289,778

Consolidated Balance Sheet (Una

Consolidated Balance Sheet (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Assets
Cash and due from banks	$ 1,249,704	$ 1,289,965
Interest-bearing deposits at banks	4,713,266	6,470,867
Federal funds sold		83,392
Trading account	340,710	308,175
Investment securities (includes pledged securities that can be sold or repledged of $1,614,909 at September 30, 2015; $1,631,267 at December 31, 2014)
Available for sale (cost: $10,923,234 at September 30, 2015; $8,919,324 at December 31, 2014)	11,159,509	9,156,932
Held to maturity (fair value: $3,025,687 at September 30, 2015; $3,538,282 at December 31, 2014)	2,998,486	3,507,868
Other (fair value: $336,544 at September 30, 2015; $328,742 at December 31, 2014)	336,544	328,742
Total investment securities	14,494,539	12,993,542
Loans and leases	68,766,144	66,899,369
Unearned discount	(225,896)	(230,413)
Loans and leases, net of unearned discount	68,540,248	66,668,956
Allowance for credit losses	(933,798)	(919,562)
Loans and leases, net	67,606,450	65,749,394
Premises and equipment	581,976	612,984
Goodwill	3,513,325	3,524,625
Core deposit and other intangible assets	18,179	35,027
Accrued interest and other assets	5,278,913	5,617,564
Total assets	97,797,062	96,685,535
Liabilities
Noninterest-bearing deposits	28,189,330	26,947,880
NOW accounts	2,459,527	2,307,815
Savings deposits	39,298,134	41,085,803
Time deposits	2,791,367	3,063,973
Deposits at Cayman Islands office	206,185	176,582
Total deposits	72,944,543	73,582,053
Federal funds purchased and agreements to repurchase securities	173,783	192,676
Accrued interest and other liabilities	1,582,513	1,567,951
Long-term borrowings	10,174,289	9,006,959
Total liabilities	84,875,128	84,349,639
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, 2015 and December 31, 2014; Liquidation preference of $10,000 per share: 50,000 shares at September 30, 2015 and December 31, 2014	1,231,500	1,231,500
Common stock, $.50 par, 250,000,000 shares authorized, 133,274,963 shares issued at September 30, 2015; 132,312,931 shares issued at December 31, 2014	66,637	66,157
Common stock issuable, 36,462 shares at September 30, 2015; 41,330 shares at December 31, 2014	2,341	2,608
Additional paid-in capital	3,511,182	3,409,506
Retained earnings	8,273,747	7,807,119
Accumulated other comprehensive income (loss), net	(163,473)	(180,994)
Total shareholders' equity	12,921,934	12,335,896
Total liabilities and shareholders' equity	$ 97,797,062	$ 96,685,535

Consolidated Balance Sheet (Un3

Consolidated Balance Sheet (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Pledged securities that can be sold or repledged	$ 1,614,909	$ 1,631,267
Investment securities, available for sale, amortized cost	10,923,234	8,919,324
Investment securities, held to maturity, fair value	3,025,687	3,538,282
Other, fair value	$ 336,544	$ 328,742
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	133,274,963	132,312,931
Common stock issuable, shares	36,462	41,330
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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Interest income
Loans and leases, including fees	$ 672,092	$ 647,280	$ 1,981,904	$ 1,937,531
Investment securities
Fully taxable	93,062	91,036	272,163	250,145
Exempt from federal taxes	950	1,271	3,330	4,068
Deposits at banks	3,852	3,198	10,321	7,617
Other	70	238	749	904
Total interest income	770,026	743,023	2,268,467	2,200,265
Interest expense
NOW accounts	360	394	1,020	1,021
Savings deposits	10,937	11,532	31,517	34,314
Time deposits	3,643	3,805	11,073	11,600
Deposits at Cayman Islands office	151	161	448	550
Short-term borrowings	32	19	102	76
Long-term borrowings	62,076	58,053	188,764	158,098
Total interest expense	77,199	73,964	232,924	205,659
Net interest income	692,827	669,059	2,035,543	1,994,606
Provision for credit losses	44,000	29,000	112,000	91,000
Net interest income after provision for credit losses	648,827	640,059	1,923,543	1,903,606
Other income
Mortgage banking revenues	84,035	93,532	288,238	269,237
Service charges on deposit accounts	107,259	110,071	314,860	321,637
Trust income	113,744	128,671	356,076	379,816
Brokerage services income	16,902	17,416	49,224	51,403
Trading account and foreign exchange gains	8,362	6,988	20,639	21,477
Loss on bank investment securities			(108)
Equity in earnings of Bayview Lending Group LLC	(3,721)	(4,114)	(11,043)	(12,623)
Other revenues from operations	113,118	98,547	359,043	296,683
Total other income	439,699	451,111	1,376,929	1,327,630
Other expense
Salaries and employee benefits	363,567	348,776	1,115,117	1,059,815
Equipment and net occupancy	68,470	67,713	201,792	206,964
Printing, postage and supplies	8,691	9,184	27,586	29,320
Amortization of core deposit and other intangible assets	4,090	7,358	16,848	26,654
FDIC assessments	11,090	13,193	32,551	43,836
Other costs of operations	197,908	219,135	642,925	656,664
Total other expense	653,816	665,359	2,036,819	2,023,253
Income before taxes	434,710	425,811	1,263,653	1,207,983
Income taxes	154,309	150,467	454,951	419,286
Net income	280,401	275,344	808,702	788,697
Net income available to common shareholders
Basic	257,337	251,905	739,627	724,307
Diluted	$ 257,346	$ 251,917	$ 739,656	$ 724,344
Net income per common share
Basic	$ 1.94	$ 1.92	$ 5.59	$ 5.54
Diluted	1.93	1.91	5.56	5.50
Cash dividends per common share	$ 0.70	$ 0.70	$ 2.10	$ 2.10
Average common shares outstanding
Basic	132,630	131,265	132,347	130,782
Diluted	133,376	132,128	133,089	131,698

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Partners' Capital [Abstract]
Net income	$ 280,401	$ 275,344	$ 808,702	$ 788,697
Other comprehensive income (loss), net of tax and reclassification adjustments:
Net unrealized gains (losses) on investment securities	48,332	(27,637)	1,053	75,229
Unrealized gains (losses) on cash flow hedges	(24)	613	823	(98)
Foreign currency translation adjustment	(3)	(1,817)	(521)	(1,504)
Defined benefit plans liability adjustment	5,724	1,000	16,166	2,999
Total other comprehensive income (loss)	54,029	(27,841)	17,521	76,626
Total comprehensive income	$ 334,430	$ 247,503	$ 826,223	$ 865,323

Consolidated Statement of Cash

Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities
Net income	$ 808,702	$ 788,697
Adjustments to reconcile net income to net cash provided by operating activities
Provision for credit losses	112,000	91,000
Depreciation and amortization of premises and equipment	73,916	74,516
Amortization of capitalized servicing rights	36,730	51,572
Amortization of core deposit and other intangible assets	16,848	26,654
Provision for deferred income taxes	20,141	33,777
Asset write-downs	5,775	5,114
Net gain on sales of assets	(61,969)	(3,771)
Net change in accrued interest receivable, payable	(5,484)	9,638
Net change in other accrued income and expense	11,200	(89,425)
Net change in loans originated for sale	232,974	(224,425)
Net change in trading account assets and liabilities	(2,993)	11,163
Net cash provided by operating activities	1,247,840	774,510
Cash flows from investing activities
Proceeds from sales of investment securities Available for sale	2,579	16
Proceeds from sales of investment securities Other	377	23,309
Proceeds from maturities of investment securities Available for sale	1,343,869	686,183
Proceeds from maturities of investment securities Held to maturity	519,359	337,677
Purchases of investment securities Available for sale	(3,320,931)	(5,310,246)
Purchases of investment securities Held to maturity	(22,592)	(15,202)
Purchases of investment securities Other	(8,179)	(53,264)
Net increase in loans and leases	(2,208,660)	(1,420,572)
Net (increase) decrease in interest-bearing deposits at banks	1,757,601	(6,024,926)
Capital expenditures, net	(42,744)	(50,400)
Net (increase) decrease in loan servicing advances	461,700	(340,750)
Other, net	(75,449)	38,707
Net cash used by investing activities	(1,593,070)	(12,129,468)
Cash flows from financing activities
Net increase (decrease) in deposits	(636,144)	7,225,487
Net decrease in short-term borrowings	(18,893)	(95,846)
Proceeds from long-term borrowings	1,500,000	4,345,478
Payments on long-term borrowings	(324,308)	(373,642)
Proceeds from issuance of preferred stock		346,500
Dividends paid - common	(281,149)	(278,118)
Dividends paid - preferred	(58,003)	(46,966)
Other, net	40,074	82,774
Net cash provided by financing activities	221,577	11,205,667
Net decrease in cash and cash equivalents	(123,653)	(149,291)
Cash and cash equivalents at beginning of period	1,373,357	1,672,934
Cash and cash equivalents at end of period	1,249,704	1,523,643
Supplemental disclosure of cash flow information
Interest received during the period	2,234,476	2,147,236
Interest paid during the period	234,989	185,377
Income taxes paid during the period	373,016	329,621
Supplemental schedule of noncash investing and financing activities
Securitization of residential mortgage loans allocated to Available-for-sale investment securities	51,481	110,971
Securitization of residential mortgage loans allocated to capitalized servicing rights	528	1,429
Real estate acquired in settlement of loans	$ 35,018	$ 35,422

Consolidated Statement of Chang

Consolidated Statement of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Series E Preferred Stock [Member]	Preferred Stock [Member]	Preferred Stock [Member]Series E 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]	Additional Paid-in Capital [Member]Series E Preferred Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss), Net [Member]
Beginning balance at Dec. 31, 2013	$ 11,305,532		$ 881,500		$ 65,258		$ 2,915	$ 3,232,014			$ 7,188,004	$ (64,159)
Total comprehensive income	865,323										788,697	76,626
Preferred stock cash dividends	(55,560)										(55,560)
Exercise of stock warrants into common stock						$ 78			$ (78)
Issuance of Series E preferred stock		$ 346,500		$ 350,000						$ (3,500)
Stock-based compensation plans:
Compensation expense, net	34,245				128			34,117
Exercises of stock options, net	103,230				535			102,695
Stock purchase plan	9,588				43			9,545
Directors' stock plan	1,271				5			1,266
Deferred compensation plans, net, including dividend equivalents	(74)				3		(325)	335			(87)
Other	1,320							1,320
Common stock cash dividends - $2.10 per share	(278,059)										(278,059)
Ending balance at Sep. 30, 2014	12,333,316		1,231,500		66,050		2,590	3,377,714			7,642,995	12,467
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)

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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
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	395,905	2,315	395,905
Exercise of warrants into shares of common stock			904	156,521
Retained Earnings [Member]
Common stock per share dividend amount			$ 2.10	$ 2.10

Significant accounting policies

Significant accounting policies	9 Months Ended
	Sep. 30, 2015
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 the 2014 Annual Report. Additionally, effective January 1, 2015 the Company made an accounting policy election in accordance with amended accounting guidance issued by the Financial Accounting Standards Board in January 2014 to account for investments in qualified affordable housing projects using the proportional amortization method. Under the proportional amortization method, the Company amortizes the initial cost of the investment in proportion to the tax credits and other tax benefits received and recognizes the net investment performance in the income statement as a component of income tax expense. The adoption of the amended guidance did not have a significant effect on the Company’s financial position or results of operations, but did result in the restatement of the consolidated statement of income for the three months and nine months ended September 30, 2014 to remove $14 million and $39 million, respectively, of losses associated with qualified affordable housing projects from “other costs of operations” and include the amortization of the initial cost of the investment in income tax expense. The cumulative effect adjustment associated with adopting the amended guidance was not material as of the beginning of any period presented in these consolidated financial statements. See note 11 for information regarding the Company’s investments in qualified affordable housing projects. In the opinion of management, all adjustments necessary for a fair presentation have been made and, except as described above, were all of a normal recurring nature.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2015
Business Combinations [Abstract]
Acquisitions	2. Acquisitions On August 27, 2012, M&T announced that it had entered into a definitive agreement with Hudson City Bancorp, Inc. (“Hudson City”), headquartered in Paramus, New Jersey, under which Hudson City would be acquired by M&T. Pursuant to the terms of the agreement, Hudson City shareholders will receive consideration for each common share of Hudson City in an amount valued at .08403 of an M&T share in the form of either M&T common stock or cash, based on the election of each Hudson City shareholder, subject to proration as specified in the merger agreement (which provides for an aggregate split of total consideration of 60% common stock of M&T and 40% cash). As of September 30, 2015, total consideration to be paid was valued at approximately $5.3 billion. The merger has received the approval of the common shareholders of M&T and Hudson City. M&T announced on September 30, 2015 that it had received the approval of the Federal Reserve to acquire Hudson City and on October 9, 2015 M&T received approval of the proposed acquisition from the New York State Department of Financial Services. The transaction is expected to be completed on or about November 1, 2015 pending the satisfaction of customary closing conditions. At September 30, 2015, Hudson City had $35.1 billion of assets, including $19.2 billion of loans and $8.3 billion of investment securities, and $30.3 billion of liabilities, including $17.9 billion of deposits.

Investment securities

Investment securities	9 Months Ended
	Sep. 30, 2015
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 Gross Gross Estimated (in thousands) September 30, 2015 Investment securities available for sale: U.S. Treasury and federal agencies $ 197,764 1,630 — $ 199,394 Obligations of states and political subdivisions 6,174 170 48 6,296 Mortgage-backed securities: Government issued or guaranteed 10,504,756 228,333 19,041 10,714,048 Privately issued 82 2 2 82 Collateralized debt obligations 28,467 22,465 1,056 49,876 Other debt securities 136,793 1,650 17,975 120,468 Equity securities 49,198 20,360 213 69,345 10,923,234 274,610 38,335 11,159,509 Investment securities held to maturity: Obligations of states and political subdivisions 125,251 1,395 347 126,299 Mortgage-backed securities: Government issued or guaranteed 2,679,546 69,486 4,787 2,744,245 Privately issued 186,883 1,628 40,174 148,337 Other debt securities 6,806 — — 6,806 2,998,486 72,509 45,308 3,025,687 Other securities 336,544 — — 336,544 Total $ 14,258,264 347,119 83,643 $ 14,521,740 Amortized Gross Gross Estimated (in thousands) December 31, 2014 Investment securities available for sale: U.S. Treasury and federal agencies $ 161,408 544 5 $ 161,947 Obligations of states and political subdivisions 8,027 224 53 8,198 Mortgage-backed securities: Government issued or guaranteed 8,507,571 223,889 337 8,731,123 Privately issued 104 2 3 103 Collateralized debt obligations 30,073 21,276 1,033 50,316 Other debt securities 138,240 1,896 18,648 121,488 Equity securities 73,901 11,020 1,164 83,757 8,919,324 258,851 21,243 9,156,932 Investment securities held to maturity: Obligations of states and political subdivisions 148,961 2,551 189 151,323 Mortgage-backed securities: Government issued or guaranteed 3,149,320 78,485 7,000 3,220,805 Privately issued 201,733 1,143 44,576 158,300 Other debt securities 7,854 — — 7,854 3,507,868 82,179 51,765 3,538,282 Other securities 328,742 — — 328,742 Total $ 12,755,934 341,030 73,008 $ 13,023,956 There were no significant gross realized gains or losses from the sale of investment securities for the three-month and nine-month periods ended September 30, 2015 and 2014, respectively. At September 30, 2015, the amortized cost and estimated fair value of debt securities by contractual maturity were as follows: Amortized cost Estimated (in thousands) Debt securities available for sale: Due in one year or less $ 8,282 8,330 Due after one year through five years 197,796 199,712 Due after five years through ten years 3,296 3,495 Due after ten years 159,824 164,497 369,198 376,034 Mortgage-backed securities available for sale 10,504,838 10,714,130 $ 10,874,036 11,090,164 Debt securities held to maturity: Due in one year or less $ 30,523 30,706 Due after one year through five years 74,511 75,150 Due after five years through ten years 20,217 20,443 Due after ten years 6,806 6,806 132,057 133,105 Mortgage-backed securities held to maturity 2,866,429 2,892,582 $ 2,998,486 3,025,687 A summary of investment securities that as of September 30, 2015 and December 31, 2014 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 Fair value Unrealized (in thousands) September 30, 2015 Investment securities available for sale: Obligations of states and political subdivisions $ 516 (2 ) 1,405 (46 ) Mortgage-backed securities: Government issued or guaranteed 1,942,135 (18,925 ) 5,503 (116 ) Privately issued — — 48 (2 ) Collateralized debt obligations 5,733 (324 ) 2,155 (732 ) Other debt securities 19,335 (458 ) 86,813 (17,517 ) Equity securities — — 212 (213 ) 1,967,719 (19,709 ) 96,136 (18,626 ) Investment securities held to maturity: Obligations of states and political subdivisions 37,336 (292 ) 4,096 (55 ) Mortgage-backed securities: Government issued or guaranteed 16,619 (129 ) 240,730 (4,658 ) Privately issued — — 118,840 (40,174 ) 53,955 (421 ) 363,666 (44,887 ) Total $ 2,021,674 (20,130 ) 459,802 (63,513 ) December 31, 2014 Investment securities available for sale: U.S. Treasury and federal agencies $ 6,505 (5 ) — — Obligations of states and political subdivisions 1,785 (52 ) 121 (1 ) Mortgage-backed securities: Government issued or guaranteed 39,001 (186 ) 5,555 (151 ) Privately issued — — 65 (3 ) Collateralized debt obligations 2,108 (696 ) 5,512 (337 ) Other debt securities 14,017 (556 ) 92,661 (18,092 ) Equity securities 2,138 (1,164 ) — — 65,554 (2,659 ) 103,914 (18,584 ) Investment securities held to maturity: Obligations of states and political subdivisions 29,886 (184 ) 268 (5 ) Mortgage-backed securities: Government issued or guaranteed 137,413 (361 ) 446,780 (6,639 ) Privately issued — — 127,512 (44,576 ) 167,299 (545 ) 574,560 (51,220 ) Total $ 232,853 (3,204 ) 678,474 (69,804 ) The Company owned 320 individual investment securities with aggregate gross unrealized losses of $84 million at September 30, 2015. Based on a review of each of the securities in the investment securities portfolio at September 30, 2015, the Company concluded that it expected to recover the amortized cost basis of its investment. As of September 30, 2015, 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, 2015, the Company has not identified events or changes in circumstances which may have a significant adverse effect on the fair value of the $337 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, 2015
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 acquired loans that were recorded at fair value at the acquisition date and included in the consolidated balance sheet follow: September 30, December 31, 2015 2014 (in thousands) Outstanding principal balance $ 2,410,454 3,070,268 Carrying amount: Commercial, financial, leasing, etc. 103,583 247,820 Commercial real estate 728,376 961,828 Residential real estate 385,885 453,360 Consumer 812,117 933,537 $ 2,029,961 2,596,545 Purchased impaired loans included in the table above totaled $149 million at September 30, 2015 and $198 million at December 31, 2014, representing less than 1% of the Company’s assets as of each date. A summary of changes in the accretable yield for acquired loans for the three months and nine months ended September 30, 2015 and 2014 follows: Three months ended September 30 2015 2014 Purchased Other Purchased Other impaired acquired impaired acquired (in thousands) Balance at beginning of period $ 77,624 344,989 $ 26,082 450,970 Interest income (5,865 ) (37,396 ) (4,149 ) (39,019 ) Reclassifications from nonaccretable balance 47 769 129 9,673 Other (a) — 4,697 — 1,870 Balance at end of period $ 71,806 313,059 $ 22,062 423,494 Nine months ended September 30 2015 2014 Purchased Other Purchased Other impaired acquired impaired acquired (in thousands) Balance at beginning of period $ 76,518 397,379 $ 37,230 538,633 Interest income (16,843 ) (118,697 ) (15,583 ) (135,105 ) Reclassifications from nonaccretable balance 12,131 27,792 415 10,448 Other (a) — 6,585 — 9,518 Balance at end of period $ 71,806 313,059 $ 22,062 423,494 (a) Other changes in expected cash flows including changes in interest rates and prepayment assumptions. A summary of current, past due and nonaccrual loans as of September 30, 2015 and December 31, 2014 follows: 30-89 90 Days or Purchased Nonaccrual Total Current Non- Acquired (in thousands) September 30, 2015 Commercial, financial, leasing, etc. $ 19,965,307 29,451 5,882 3,477 4,645 224,415 $ 20,233,177 Real estate: Commercial 23,184,906 105,140 21,629 17,906 45,523 176,491 23,551,595 Residential builder and developer 1,479,659 15,951 — 7,488 65,102 46,022 1,614,222 Other commercial construction 3,493,349 28,433 1,373 1,769 17,484 12,312 3,554,720 Residential 7,323,813 206,044 194,280 16,295 14,392 153,354 7,908,178 Residential Alt-A 226,871 11,662 — — — 64,351 302,884 Consumer: Home equity lines and loans 5,710,632 38,506 — 15,454 2,275 78,126 5,844,993 Automobile 2,319,556 36,867 — 53 — 13,892 2,370,368 Other 3,084,080 31,210 8,301 18,385 — 18,135 3,160,111 Total $ 66,788,173 503,264 231,465 80,827 149,421 787,098 $ 68,540,248 Current 30-89 90 Days or Purchased Nonaccrual Total Non- Acquired (in thousands) December 31, 2014 Commercial, financial, leasing, etc. $ 19,228,265 37,246 1,805 6,231 10,300 177,445 $ 19,461,292 Real estate: Commercial 22,208,491 118,704 22,170 14,662 51,312 141,600 22,556,939 Residential builder and developer 1,273,607 11,827 492 9,350 98,347 71,517 1,465,140 Other commercial construction 3,484,932 17,678 — — 17,181 25,699 3,545,490 Residential 7,640,368 226,932 216,489 35,726 18,223 180,275 8,318,013 Residential Alt-A 249,810 11,774 — — — 77,704 339,288 Consumer: Home equity lines and loans 5,859,378 42,945 — 27,896 2,374 89,291 6,021,884 Automobile 1,931,138 30,500 — 133 — 17,578 1,979,349 Other 2,909,791 33,295 4,064 16,369 — 18,042 2,981,561 Total $ 64,785,780 530,901 245,020 110,367 197,737 799,151 $ 66,668,956 (a) Acquired loans that were recorded at fair value at acquisition date. This category does not include purchased impaired loans that are presented separately. (b) Accruing loans that were impaired at acquisition date and were recorded at fair value. One-to-four family residential mortgage loans held for sale were $422 million and $435 million at September 30, 2015 and December 31, 2014, respectively. Commercial mortgage loans held for sale were $71 million at September 30, 2015 and $308 million at December 31, 2014. Changes in the allowance for credit losses for the three months ended September 30, 2015 were as follows: Commercial, Real Estate 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 three months ended September 30, 2014 were as follows: Commercial, Real Estate Commercial Residential Consumer Unallocated Total (in thousands) Beginning balance $ 292,251 311,254 72,404 165,871 75,886 $ 917,666 Provision for credit losses 2,373 8,046 (3,187 ) 21,815 (47 ) 29,000 Net charge-offs Charge-offs (15,921 ) (1,666 ) (4,193 ) (21,312 ) — (43,092 ) Recoveries 7,849 1,267 2,498 3,445 — 15,059 Net charge-offs (8,072 ) (399 ) (1,695 ) (17,867 ) — (28,033 ) Ending balance $ 286,552 318,901 67,522 169,819 75,839 $ 918,633 Changes in the allowance for credit losses for the nine months ended September 30, 2015 were as follows: Commercial, Real Estate 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 Changes in the allowance for credit losses for the nine months ended September 30, 2014 were as follows: Commercial, Real Estate Commercial Residential Consumer Unallocated Total (in thousands) Beginning balance $ 273,383 324,978 78,656 164,644 75,015 $ 916,676 Provision for credit losses 40,527 (4,067 ) (916 ) 54,632 824 91,000 Net charge-offs Charge-offs (44,872 ) (7,966 ) (17,124 ) (62,407 ) — (132,369 ) Recoveries 17,514 5,956 6,906 12,950 — 43,326 Net charge-offs (27,358 ) (2,010 ) (10,218 ) (49,457 ) — (89,043 ) Ending balance $ 286,552 318,901 67,522 169,819 75,839 $ 918,633 Despite the above allocation, the allowance for credit losses is general in nature and is available to absorb losses from any loan or lease type. In establishing the allowance for credit losses, the Company estimates losses attributable to specific troubled credits identified through both normal and detailed or intensified credit review processes and also estimates losses inherent in other loans and leases on a collective basis. For purposes of determining the level of the allowance for credit losses, the Company evaluates its loan and lease portfolio by loan type. The amounts of loss components in the Company’s loan and lease portfolios are determined through a loan-by-loan analysis of larger balance commercial loans and commercial real estate loans that are in nonaccrual status and by applying loss factors to groups of loan balances based on loan type and management’s classification of such loans under the Company’s loan grading system. Measurement of the specific loss components is typically based on expected future cash flows, collateral values and other factors that may impact the borrower’s ability to pay. In determining the allowance for credit losses, the Company utilizes a loan grading system which is applied to commercial and commercial real estate credits on an individual loan basis. Loan officers are responsible for 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. Information with respect to loans and leases that were considered impaired follows. September 30, 2015 December 31, 2014 Recorded Unpaid Related Recorded Unpaid Related (in thousands) With an allowance recorded: Commercial, financial, leasing, etc. $ 144,051 166,877 35,195 132,340 165,146 31,779 Real estate: Commercial 105,561 122,369 18,932 83,955 96,209 14,121 Residential builder and developer 6,544 10,276 788 17,632 22,044 805 Other commercial construction 2,445 3,991 391 5,480 6,484 900 Residential 83,349 101,367 4,775 88,970 107,343 4,296 Residential Alt-A 93,168 107,075 8,500 101,137 114,565 11,000 Consumer: Home equity lines and loans 23,257 24,239 3,541 19,771 20,806 6,213 Automobile 23,985 23,985 5,118 30,317 30,317 8,070 Other 18,870 18,870 5,486 18,973 18,973 5,459 501,230 579,049 82,726 498,575 581,887 82,643 With no related allowance recorded: Commercial, financial, leasing, etc. 111,023 133,100 — 73,978 81,493 — Real estate: Commercial 77,147 84,677 — 66,777 78,943 — Residential builder and developer 42,800 68,906 — 58,820 96,722 — Other commercial construction 10,307 28,480 — 20,738 41,035 — Residential 16,232 26,626 — 16,815 26,750 — Residential Alt-A 20,891 35,836 — 26,752 46,964 — 278,400 377,625 — 263,880 371,907 — Total: Commercial, financial, leasing, etc. 255,074 299,977 35,195 206,318 246,639 31,779 Real estate: Commercial 182,708 207,046 18,932 150,732 175,152 14,121 Residential builder and developer 49,344 79,182 788 76,452 118,766 805 Other commercial construction 12,752 32,471 391 26,218 47,519 900 Residential 99,581 127,993 4,775 105,785 134,093 4,296 Residential Alt-A 114,059 142,911 8,500 127,889 161,529 11,000 Consumer: Home equity lines and loans 23,257 24,239 3,541 19,771 20,806 6,213 Automobile 23,985 23,985 5,118 30,317 30,317 8,070 Other 18,870 18,870 5,486 18,973 18,973 5,459 Total $ 779,630 956,674 82,726 762,455 953,794 82,643 Three months ended Three months ended Interest income Interest income Average Total Cash Average Total Cash (in thousands) Commercial, financial, leasing, etc. $ 242,157 1,017 1,017 228,749 611 611 Real estate: Commercial 179,327 2,327 2,327 189,952 821 821 Residential builder and developer 53,009 81 81 90,493 18 18 Other commercial construction 17,236 1,943 1,943 58,500 251 251 Residential 99,939 1,835 1,316 104,516 1,328 776 Residential Alt-A 116,191 1,539 618 131,574 1,643 681 Consumer: Home equity lines and loans 21,952 231 66 19,268 219 81 Automobile 24,429 391 39 33,666 528 67 Other 19,238 188 23 18,677 177 44 Total $ 773,478 9,552 7,430 875,395 5,596 3,350 Nine months ended Nine months ended Interest income Interest income Average Total Cash Average Total Cash (in thousands) Commercial, financial, leasing, etc. $ 226,243 2,123 2,123 171,227 1,379 1,379 Real estate: Commercial 161,834 4,433 4,433 194,337 2,616 2,616 Residential builder and developer 64,165 275 275 94,453 131 131 Other commercial construction 22,130 2,166 2,166 74,531 1,694 1,694 Residential 101,997 4,639 3,011 132,606 7,784 6,146 Residential Alt-A 120,710 4,799 1,962 135,374 5,002 1,900 Consumer: Home equity lines and loans 20,619 656 179 17,902 540 182 Automobile 26,521 1,257 136 36,560 1,742 228 Other 19,053 547 86 18,229 517 145 Total $ 763,272 20,895 14,371 875,219 21,405 14,421 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 $59 million and $20 million, respectively, at September 30, 2015 and $63 million and $18 million, respectively, at December 31, 2014. 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 $28 million, respectively, at September 30, 2015 and $27 million and $28 million, respectively, at December 31, 2014. 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. Real Estate Commercial, Residential Other Financial, Builder and Commercial Leasing, etc. Commercial Developer Construction (in thousands) September 30, 2015 Pass $ 19,223,102 22,479,501 1,507,057 3,447,841 Criticized accrual 785,660 895,603 61,143 94,567 Criticized nonaccrual 224,415 176,491 46,022 12,312 Total $ 20,233,177 23,551,595 1,614,222 3,554,720 December 31, 2014 Pass $ 18,695,440 21,837,022 1,347,778 3,347,522 Criticized accrual 588,407 578,317 45,845 172,269 Criticized nonaccrual 177,445 141,600 71,517 25,699 Total $ 19,461,292 22,556,939 1,465,140 3,545,490 The Company also measures additional losses for purchased impaired loans when it is probable that the Company will be unable to collect all cash flows expected at acquisition plus additional cash flows expected to be collected arising from changes in estimates after acquisition. The determination of the allocated portion of the allowance for credit losses is very subjective. Given that inherent subjectivity and potential imprecision involved in determining the allocated portion of the allowance for credit losses, the Company also provides an inherent unallocated portion of the allowance. The unallocated portion of the allowance is intended to recognize probable losses that are not otherwise identifiable and includes management’s subjective determination of amounts necessary to provide for the possible use of imprecise estimates in determining the allocated portion of the allowance. Therefore, the level of the unallocated portion of the allowance is primarily reflective of the inherent imprecision in the various calculations used in determining the allocated portion of the allowance for credit losses. Other factors that could also lead to changes in the unallocated portion include the effects of expansion into new markets for which the Company does not have the same degree of familiarity and experience regarding portfolio performance in changing market conditions, the introduction of new loan and lease product types, and other risks associated with the Company’s loan portfolio that may not be specifically identifiable. The allocation of the allowance for credit losses summarized on the basis of the Company’s impairment methodology was as follows: Commercial, Financial, Real Estate Leasing, etc. Commercial Residential Consumer Total (in thousands) September 30, 2015 Individually evaluated for impairment $ 35,195 19,743 13,275 14,145 $ 82,358 Collectively evaluated for impairment 250,271 292,214 39,804 186,706 768,995 Purchased impaired 1,201 1,132 1,917 1,463 5,713 Allocated $ 286,667 313,089 54,996 202,314 857,066 Unallocated 76,732 Total $ 933,798 December 31, 2014 Individually evaluated for impairment $ 31,779 15,490 14,703 19,742 $ 81,714 Collectively evaluated for impairment 251,607 291,244 45,061 165,140 753,052 Purchased impaired 4,652 1,193 2,146 1,151 9,142 Allocated $ 288,038 307,927 61,910 186,033 843,908 Unallocated 75,654 Total $ 919,562 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, 2015 Individually evaluated for impairment $ 255,074 243,743 213,640 66,112 $ 778,569 Collectively evaluated for impairment 19,973,458 28,348,685 7,983,030 11,307,085 67,612,258 Purchased impaired 4,645 128,109 14,392 2,275 149,421 Total $ 20,233,177 28,720,537 8,211,062 11,375,472 $ 68,540,248 December 31, 2014 Individually evaluated for impairment $ 206,318 252,347 232,398 69,061 $ 760,124 Collectively evaluated for impairment 19,244,674 27,148,382 8,406,680 10,911,359 65,711,095 Purchased impaired 10,300 166,840 18,223 2,374 197,737 Total $ 19,461,292 27,567,569 8,657,301 10,982,794 $ 66,668,956 During the normal course of business, the Company modifies loans to maximize recovery efforts. If the borrower is experiencing financial difficulty and a concession is granted, the Company considers such modifications as troubled debt restructurings and classifies those loans as either nonaccrual loans or renegotiated loans. The types of concessions that the Company grants typically include principal deferrals and interest rate concessions, but may also include other types of concessions. The tables below summarize the Company’s loan modification activities that were considered troubled debt restructurings for the three months ended September 30, 2015 and 2014: Recorded investment Financial effects of Three months ended September 30, 2015 Number Pre- Post- Recorded Interest (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 Alt-A 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. Recorded investment Financial effects of Three months ended September 30, 2014 Number Pre- Post- Recorded Interest (dollars in thousands) Commercial, financial, leasing, etc. Principal deferral 15 $ 1,305 $ 1,300 $ (5 ) $ — Real estate: Commercial Principal deferral 8 2,081 2,068 (13 ) — Other 1 650 — (650 ) — Combination of concession types 4 483 478 (5 ) (95 ) Residential builder and developer Principal deferral 1 241 241 — — Other commercial construction Principal deferral 1 145 142 (3 ) — Residential Principal deferral 3 98 97 (1 ) — Combination of concession types 8 1,100 1,136 36 (135 ) Residential Alt-A Combination of concession types 3 349 369 20 (64 ) Consumer: Home equity lines and loans Combination of concession types 5 519 519 — (67 ) Automobile Principal deferral 45 1,003 1,003 — — Interest rate reduction 3 30 30 — (2 ) Other 7 96 96 — — Combination of concession types 19 348 348 — (21 ) Other Principal deferral 6 48 48 — — Interest rate reduction 1 2 2 — — Combination of concession types 24 511 511 — (121 ) Total 154 $ 9,009 $ 8,388 $ (621 ) $ (505 ) (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, 2015 and 2014: Recorded investment Financial effects of Nine months ended September 30, 2015 Number Pre- Post- Recorded Interest (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 Alt-A 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. Recorded investment Financial effects of Nine months ended September 30, 2014 Number Pre- Post- Recorded Interest (dollars in thousands) Commercial, financial, leasing, etc. Principal deferral 66 $ 20,673 $ 20,499 $ (174 ) $ — Other 1 19,593 19,593 — — Combination of concession types 5 9,836 9,766 (70 ) (14 ) Real estate: Commercial Principal deferral 32 17,452 17,384 (68 ) — Other 1 650 — (650 ) — Interest rate reduction 1 255 252 (3 ) (48 ) Combination of concession types 6 892 940 48 (208 ) Residential builder and developer Principal deferral 2 1,639 1,639 — — Other commercial construction Principal deferral 4 6,703 6,611 (92 ) — Residential Principal deferral 19 1,842 1,926 84 — Interest rate reduction 1 98 104 6 (32 ) Other 1 188 188 — — Combination of concession types 30 4,211 4,287 76 (483 ) Residential Alt-A Principal deferral 5 828 900 72 — Combination of concession types 19 3,101 3,134 33 (345 ) Consumer: Home equity lines and loans Principal deferral 3 280 280 — — Interest rate reduction 5 341 341 — (76 ) Combination of concession types 41 4,147 4,147 — (443 ) Automobile Principal deferral 168 2,599 2,599 — — Interest rate reduction 6 90 90 — (5 ) Other 26 204 204 — — Combination of concession types 65 939 939 — (83 ) Other Principal deferral 21 141 141 — — Interest rate reduction 4 293 293 — (63 ) Other 1 45 45 — — Combination of concession types 57 1,883 1,883 — (585 ) Total 590 $ 98,923 $ 98,185 $ (738 ) $ (2,385 ) (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, 2015 and 2014 and for which there was a subsequent payment default during the nine-month periods ended September 30, 2015 and 2014, respectively, were not material. Effective January 1, 2015, the Company adopted amended accounting and disclosure guidance for reclassification of residential real estate collateralized consumer mortgage loans upon foreclosure. The amended guidance clarifies that an in-substance repossession or foreclosure occurs and a creditor is considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan upon either (1) the creditor obtaining legal title to the residential real estate property upon completion of a foreclosure or (2) the borrower conveying all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. The adoption resulted in an insignificant increase in other real estate owned. The amount of foreclosed residential real estate property held by the Company was $43 million and $44 million at September 30, 2015 and December 31, 2014, respectively. At September 30, 2015, there were $151 million in loans secured by residential real estate that were in the process of foreclosure.

Borrowings

Borrowings	9 Months Ended
	Sep. 30, 2015
Debt Disclosure [Abstract]
Borrowings	5. Borrowings During February 2015, M&T Bank issued $1.5 billion of fixed rate senior notes pursuant to a Bank Note Program, of which $750 million have a 2.10% interest rate and mature in 2020 and $750 million have a 2.90% interest rate and mature in 2025. M&T had $513 million of fixed and floating rate junior subordinated deferrable interest debentures (“Junior Subordinated Debentures”) outstanding at September 30, 2015 which 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. 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. On April 15, 2015, M&T redeemed all of the issued and outstanding Capital Securities issued by M&T Capital Trust I, M&T Capital Trust II and M&T Capital Trust III, and the related Junior Subordinated Debentures held by those respective trusts. In the aggregate, $323 million of Junior Subordinated Debentures were redeemed. In February 2014, M&T redeemed all of the issued and outstanding 8.5% $350 million Capital Securities issued by M&T Capital Trust IV and the related Junior Subordinated Debentures held by M&T Capital Trust IV. Also included in long-term borrowings are agreements to repurchase securities of $1.4 billion at each of September 30, 2015 and December 31, 2014. The agreements reflect various repurchase dates in 2016 and 2017 and 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 $1.5 billion at each of September 30, 2015 and December 31, 2014.

Shareholders' equity

Shareholders' equity	9 Months Ended
	Sep. 30, 2015
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, 2015 and December 31, 2014 is presented below: Shares Carrying (dollars in thousands) Series A (a) Fixed Rate Cumulative Perpetual Preferred Stock, Series A, $1,000 liquidation preference per share 230,000 $ 230,000 Series C (a) Fixed Rate Cumulative Perpetual Preferred Stock, Series C, $1,000 liquidation preference per share 151,500 $ 151,500 Series D (b) Fixed Rate Non-Cumulative Perpetual Preferred Stock, Series D, $10,000 liquidation preference per share 50,000 $ 500,000 Series E (c) Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock Series E, $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 719,175 at September 30, 2015 and 721,490 at December 31, 2014. (b) Dividends, if declared, are paid semi-annually at a rate of 6.875% per year. The shares are redeemable in whole or in part on or after June 15, 2016. Notwithstanding M&T’s option to redeem the shares, if an event occurs such that the shares no longer qualify as Tier 1 capital, M&T may redeem all of the shares within 90 days following that occurrence. (c) Dividends, if declared, are paid semi-annually at a rate of 6.45% through February 14, 2024 and thereafter will be paid quarterly at a rate of the three-month London Interbank Offered Rate (“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, 2015 and December 31, 2014. The obligation under that warrant was assumed by M&T in an acquisition.

Pension plans and other postret

Pension plans and other postretirement benefits	9 Months Ended
	Sep. 30, 2015
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 Three months ended September 30 2015 2014 2015 2014 (in thousands) Service cost $ 5,916 5,130 188 151 Interest cost on projected benefit obligation 17,754 17,290 651 695 Expected return on plan assets (23,527 ) (22,892 ) — — Amortization of prior service credit (1,501 ) (1,638 ) (340 ) (340 ) Amortization of net actuarial loss 11,207 3,624 26 — Net periodic benefit cost $ 9,849 1,514 525 506 Pension benefits Other Nine months ended September 30 2015 2014 2015 2014 (in thousands) Service cost $ 17,748 15,390 562 453 Interest cost on projected benefit obligation 53,261 51,871 1,953 2,084 Expected return on plan assets (70,578 ) (68,676 ) — — Amortization of prior service credit (4,504 ) (4,914 ) (1,019 ) (1,019 ) Amortization of net actuarial loss 33,619 10,871 79 — Net periodic benefit cost $ 29,546 4,542 1,575 1,518 Expense incurred in connection with the Company’s defined contribution pension and retirement savings plans totaled $14,281,000 and $13,558,000 for the three months ended September 30, 2015 and 2014, respectively, and $44,377,000 and $41,963,000 for the nine months ended September 30, 2015 and 2014, respectively.

Earnings per common share

Earnings per common share	9 Months Ended
	Sep. 30, 2015
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 2015 2014 2015 2014 (in thousands, except per share) Income available to common shareholders: Net income $ 280,401 275,344 $ 808,702 788,697 Less: Preferred stock dividends (a) (20,318 ) (20,443 ) (60,953 ) (55,560 ) Net income available to common equity 260,083 254,901 747,749 733,137 Less: Income attributable to unvested stock-based compensation awards (2,746 ) (2,996 ) (8,122 ) (8,830 ) Net income available to common shareholders $ 257,337 251,905 $ 739,627 724,307 Weighted-average shares outstanding: Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards 134,049 132,832 133,805 132,372 Less: Unvested stock-based compensation awards (1,419 ) (1,567 ) (1,458 ) (1,590 ) Weighted-average shares outstanding 132,630 131,265 132,347 130,782 Basic earnings per common share $ 1.94 1.92 $ 5.59 5.54 (a) Including impact of not as yet declared cumulative dividends. The computations of diluted earnings per common share follow: Three months ended September 30 Nine months ended September 30 2015 2014 2015 2014 (in thousands, except per share) Net income available to common equity $ 260,083 254,901 $ 747,749 733,137 Less: Income attributable to unvested stock-based compensation awards (2,737 ) (2,984 ) (8,093 ) (8,793 ) Net income available to common shareholders $ 257,346 251,917 $ 739,656 724,344 Adjusted weighted-average shares outstanding: Common and unvested stock-based compensation awards 134,049 132,832 133,805 132,372 Less: Unvested stock-based compensation awards (1,419 ) (1,567 ) (1,458 ) (1,590 ) Plus: Incremental shares from assumed conversion of stock-based compensation awards and warrants to purchase common stock 746 863 742 916 Adjusted weighted-average shares outstanding 133,376 132,128 133,089 131,698 Diluted earnings per common share $ 1.93 1.91 $ 5.56 5.50 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 1.5 million and 1.7 million common shares during the three-month periods ended September 30, 2015 and 2014, respectively, and 1.9 million and 2.1 million common shares during the nine-month periods ended September 30, 2015 and 2014, 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, 2015
Equity [Abstract]
Comprehensive income	9. Comprehensive income The following table displays the components of other comprehensive income (loss) and amounts reclassified from accumulated other comprehensive income (loss) to net income: Investment Securities With All Defined Other Total Income Net (in thousands) Balance – January 1, 2015 $ 7,438 201,828 (503,027 ) (4,082 ) $ (297,843 ) 116,849 $ (180,994 ) Other comprehensive income before reclassifications: Unrealized holding gains (losses), net 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 held-to-maturity (“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 ) Investment Securities With All Defined Other Total Income Net (in thousands) Balance – January 1, 2014 $ 37,255 18,450 (161,617 ) 115 $ (105,797 ) 41,638 $ (64,159 ) Other comprehensive income before reclassifications: Unrealized holding gains, net 12,038 109,263 — — 121,301 (47,615 ) 73,686 Foreign currency translation adjustment — — — (2,314 ) (2,314 ) 810 (1,504 ) Unrealized losses on cash flow hedges — — — (162 ) (162 ) 64 (98 ) Total other comprehensive income before reclassifications 12,038 109,263 — (2,476 ) 118,825 (46,741 ) 72,084 Amounts reclassified from accumulated other comprehensive income that (increase) decrease net income: Accretion of unrealized holding losses on HTM securities 1 2,539 — — 2,540 (b) (997 ) 1,543 Amortization of prior service credit — — (5,933 ) — (5,933 )(e) 2,328 (3,605 ) Amortization of actuarial losses — — 10,871 — 10,871 (e) (4,267 ) 6,604 Total reclassifications 1 2,539 4,938 — 7,478 (2,936 ) 4,542 Total gain (loss) during the period 12,039 111,802 4,938 (2,476 ) 126,303 (49,677 ) 76,626 Balance – September 30, 2014 $ 49,294 130,252 (156,679 ) (2,361 ) $ 20,506 (8,039 ) $ 12,467 (a) Other-than-temporary impairment (b) Included in interest income (c) Included in 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 With OTTI All other plans Other Total (in thousands) Balance – December 31, 2014 $ 4,518 122,683 (305,589 ) (2,606 ) $ (180,994 ) Net gain (loss) during period 5,926 (4,873 ) 16,166 302 17,521 Balance – September 30, 2015 $ 10,444 117,810 (289,423 ) (2,304 ) $ (163,473 )

Derivative financial instrument

Derivative financial instruments	9 Months Ended
	Sep. 30, 2015
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 significant as of September 30, 2015. The net effect of interest rate swap agreements was to increase net interest income by $11 million for each of the three-month periods ended September 30, 2015 and 2014 and $33 million and $34 million for the nine-month periods ended September 30, 2015 and 2014, 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- Fixed Variable (in thousands) (in years) September 30, 2015 Fair value hedges: Fixed rate long-term borrowings (a) $ 1,400,000 1.9 4.42 % 1.29 % December 31, 2014 Fair value hedges: Fixed rate long-term borrowings (a) $ 1,400,000 2.7 4.42 % 1.19 % (a) Under the terms of these agreements, the Company receives settlement amounts at a fixed rate and pays at a variable rate. The use of cash flow hedges to manage the variability of cash flows associated with the then-forecasted issuance of long-term debt did not have a significant impact on the Company’s consolidated financial position or results of operations. 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 $17.6 billion at each of September 30, 2015 and December 31, 2014. The notional amounts of foreign currency and other option and futures contracts entered into for trading account purposes aggregated $1.6 billion and $1.3 billion at September 30, 2015 and December 31, 2014, respectively. Information about the fair values of derivative instruments in the Company’s consolidated balance sheet and consolidated statement of income follows: Asset derivatives Liability derivatives Fair value Fair value September 30, December 31, September 30, December 31, (in thousands) Derivatives designated and qualifying as hedging instruments Fair value hedges: Interest rate swap agreements (a) $ 60,782 73,251 $ — — Commitments to sell real estate loans (a) 899 728 5,142 4,217 61,681 73,979 5,142 4,217 Derivatives not designated and qualifying as hedging instruments Mortgage-related commitments to originate real estate loans for sale (a) 17,832 17,396 185 49 Commitments to sell real estate loans (a) 26 754 4,162 4,330 Trading: Interest rate contracts (b) 268,332 215,614 221,626 173,513 Foreign exchange and other option and futures contracts (b) 13,404 31,112 11,380 29,950 299,594 264,876 237,353 207,842 Total derivatives $ 361,275 338,855 $ 242,495 212,059 (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 Three months ended Derivative Hedged item Derivative Hedged item (in thousands) Derivatives in fair value hedging relationships Interest rate swap agreements: Fixed rate long-term borrowings (a) $ (2,719 ) 2,382 $ (16,792 ) 16,380 Derivatives not designated as hedging instruments Trading: Interest rate contracts (b) $ 4,120 $ 132 Foreign exchange and other option and futures contracts (b) 2,441 (781 ) Total $ 6,561 $ (649 ) Amount of gain (loss) recognized Nine months ended Nine months ended Derivative Hedged item Derivative Hedged item (in thousands) Derivatives in fair value hedging relationships Interest rate swap agreements: Fixed rate long-term borrowings (a) $ (12,469 ) 11,495 $ (26,627 ) 25,658 Derivatives not designated as hedging instruments Trading: Interest rate contracts (b) $ 6,552 $ 1,214 Foreign exchange and other option and futures contracts (b) 1,563 (6,597 ) Total $ 8,115 $ (5,383 ) (a) Reported as other revenues from operations. (b) Reported as trading account and foreign exchange gains. In addition, the Company also has commitments to sell and commitments to originate residential and commercial real estate loans that are considered derivatives. The Company designates certain of the commitments to sell real estate loans as fair value hedges of real estate loans held for sale. The Company also utilizes commitments to sell real estate loans to offset the exposure to changes in the fair value of certain commitments to originate real estate loans for sale. As a result of these activities, net unrealized pre-tax gains related to hedged loans held for sale, commitments to originate loans for sale and commitments to sell loans were approximately $23 million and $28 million at September 30, 2015 and December 31, 2014, 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 $96 million and $161 million at September 30, 2015 and December 31, 2014, respectively. After consideration of such netting arrangements, the net liability positions with counterparties aggregated $91 million and $103 million at September 30, 2015 and December 31, 2014, respectively. The Company was required to post collateral relating to those positions of $81 million and $90 million at September 30, 2015 and December 31, 2014, 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 to the derivative financial instruments could demand immediate incremental collateralization on those instruments in a net liability position. The aggregate fair value of all derivative financial instruments with such credit risk-related contingent features in a net liability position on September 30, 2015 was $17 million, for which the Company had posted collateral of $11 million in the normal course of business. If the credit-risk-related contingent features had been triggered on September 30, 2015, the maximum amount of additional collateral the Company would have been required to post to counterparties was $6 million. The aggregate fair value of derivative financial instruments in an asset position, which are subject to enforceable master netting arrangements, was $40 million and $104 million at September 30, 2015 and December 31, 2014, respectively. After consideration of such netting arrangements, the net asset positions with counterparties aggregated $35 million and $46 million at September 30, 2015 and December 31, 2014, respectively. Counterparties posted collateral relating to those positions of $35 million and $46 million at September 30, 2015 and December 31, 2014, 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 was a net liability position of $96 million and $35 million at September 30, 2015 and December 31, 2014, respectively. Collateral posted with clearinghouses was $143 million and $61 million at September 30, 2015 and December 31, 2014, respectively.

Variable interest entities and

Variable interest entities and asset securitizations	9 Months Ended
	Sep. 30, 2015
Text Block [Abstract]
Variable interest entities and asset securitizations	11. Variable interest entities and asset securitizations During the three and nine months ended September 30, 2015, the Company securitized approximately $15 million and $51 million, respectively, of one-to-four family residential real estate loans that had been originated for sale in guaranteed mortgage securitizations with the Government National Mortgage Association ( “ ” In accordance with GAAP, the Company determined that it was the primary beneficiary of a residential mortgage loan securitization trust considering its role as servicer and its retained subordinated interests in the trust. As a result, the Company has included the one-to-four family residential mortgage loans that were included in the trust in its consolidated financial statements. At September 30, 2015 and December 31, 2014, the carrying values of the loans in the securitization trust were $84 million and $98 million, respectively. The outstanding principal amount of mortgage-backed securities issued by the qualified special purpose trust that was held by parties unrelated to M&T at September 30, 2015 and December 31, 2014 was $13 million and $15 million, respectively. Because the transaction was non-recourse, the Company’s maximum exposure to loss as a result of its association with the trust at September 30, 2015 is limited to realizing the carrying value of the loans less the amount of the mortgage-backed securities held by the third parties. 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, 2015 and December 31, 2014, the Company included the junior subordinated debentures as “long-term borrowings” in its consolidated balance sheet and recognized $24 million and $34 million, respectively, 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 $1.2 billion at September 30, 2015 and December 31, 2014, respectively. 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 $301 million, including $85 million of unfunded commitments, at September 30, 2015 and $243 million, including $56 million of unfunded commitments, at December 31, 2014. Contingent commitments to provide additional capital contributions to these partnerships were not material at September 30, 2015. 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. As described in note 1, effective January 1, 2015 the Company retrospectively adopted for all periods presented amended accounting guidance on the accounting for investments in qualified affordable housing projects whereby 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 $10 million and $31 million of its investments in qualified affordable housing projects to income tax expense during the three months and nine months ended September 30, 2015, respectively, and recognized $15 million and $44 million of tax credits and other tax benefits during those respective periods. Similarly, for the three months and nine months ended September 30, 2014, the Company amortized $14 million and $39 million, respectively, of its investments in qualified affordable housing projects to income tax expense, and recognized $18 million and $53 million of tax credits and other tax benefits during those respective periods.

Fair value measurements

Fair value measurements	9 Months Ended
	Sep. 30, 2015
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, 2015. Pursuant to GAAP, fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. A three-level hierarchy exists in GAAP for fair value measurements based upon the inputs to the valuation of an asset or liability. • Level 1 — Valuation is based on quoted prices in active markets for identical assets and liabilities. • Level 2 — Valuation is determined from quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar instruments in markets that are not active or by model-based techniques in which all significant inputs are observable in the market. • Level 3 — Valuation is derived from model-based and other techniques in which at least one significant input is unobservable and which may be based on the Company’s own estimates about the assumptions that market participants would use to value the asset or liability. When available, the Company attempts to use quoted market prices in active markets to determine fair value and classifies such items as Level 1 or Level 2. If quoted market prices in active markets are not available, fair value is often determined using model-based techniques incorporating various assumptions including interest rates, prepayment speeds and credit losses. Assets and liabilities valued using model-based techniques are classified as either Level 2 or Level 3, depending on the lowest level classification of an input that is considered significant to the overall valuation. The following is a description of the valuation methodologies used for the Company’s assets and liabilities that are measured on a recurring basis at estimated fair value. Trading account assets and liabilities Trading account assets and liabilities consist primarily of interest rate swap agreements and foreign exchange contracts with customers who require such services with offsetting positions with third parties to minimize the Company’s risk with respect to such transactions. The Company generally determines the fair value of its derivative trading account assets and liabilities using externally developed pricing models based on market observable inputs and, therefore, classifies such valuations as Level 2. Mutual funds held in connection with deferred compensation 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 are securities backed by trust preferred securities issued by financial institutions and other entities. The Company could not obtain pricing indications for many of these securities from its two primary independent pricing sources. The Company, therefore, performed internal modeling to estimate the cash flows and fair value of its portfolio of securities backed by trust preferred securities at September 30, 2015 and December 31, 2014. 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 September 30, 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 $50 million, respectively, and at December 31, 2014 were $30 million and $50 million, respectively. 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. 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 originated for sale from the date of close through the sale date. The fair value of hedged real estate loans held for sale is generally calculated by reference to quoted prices in secondary markets for commitments to sell real estate loans with similar characteristics and, accordingly, such loans have been classified as a Level 2 valuation. Commitments to originate real estate loans for sale and commitments to sell real estate loans The Company enters into various commitments to originate real estate loans for sale and commitments to sell real estate loans. Such commitments are considered to be derivative financial instruments and, therefore, are carried at estimated fair value on the consolidated balance sheet. The estimated fair values of such commitments were generally calculated by reference to quoted prices in secondary markets for commitments to sell real estate loans to certain government-sponsored entities and other parties. The fair valuations of commitments to sell real estate loans generally result in a Level 2 classification. The estimated fair value of commitments to originate real estate loans for sale are adjusted to reflect the Company’s anticipated commitment expirations. The estimated commitment expirations are considered significant unobservable inputs contributing to the Level 3 classification of commitments to originate real estate loans for sale. Significant unobservable inputs used in the determination of estimated fair value of commitments to originate real estate loans for sale are included in the accompanying table of significant unobservable inputs to Level 3 measurements. Interest rate swap agreements used for interest rate risk management The Company utilizes interest rate swap agreements as part of the management of interest rate risk to modify the repricing characteristics of certain portions of its portfolios of earning assets and interest-bearing liabilities. The Company generally determines the fair value of its interest rate swap agreements using externally developed pricing models based on market observable inputs and, therefore, classifies such valuations as Level 2. The Company has considered counterparty credit risk in the valuation of its interest rate swap agreement assets and has considered its own credit risk in the valuation of its interest rate swap agreement liabilities. The following tables present assets and liabilities at September 30, 2015 and December 31, 2014 measured at estimated fair value on a recurring basis: Fair value Level 1 (a) Level 2 (a) Level 3 (in thousands) Trading account assets $ 340,710 48,006 292,704 — Investment securities available for sale: U.S. Treasury and federal agencies 199,394 — 199,394 — Obligations of states and political subdivisions 6,296 — 6,296 — Mortgage-backed securities: Government issued or guaranteed 10,714,048 — 10,714,048 — Privately issued 82 — — 82 Collateralized debt obligations 49,876 — — 49,876 Other debt securities 120,468 — 120,468 — Equity securities 69,345 40,370 28,975 — 11,159,509 40,370 11,069,181 49,958 Real estate loans held for sale 493,453 — 493,453 — Other assets (b) 79,539 — 61,707 17,832 Total assets $ 12,073,211 88,376 11,917,045 67,790 Trading account liabilities $ 233,006 — 233,006 — Other liabilities (b) 9,489 — 9,304 185 Total liabilities $ 242,495 — 242,310 185 Fair value Level 1 (a) Level 2 (a) Level 3 (in thousands) Trading account assets $ 308,175 51,416 256,759 — Investment securities available for sale: U.S. Treasury and federal agencies 161,947 — 161,947 — Obligations of states and political subdivisions 8,198 — 8,198 — Mortgage-backed securities: Government issued or guaranteed 8,731,123 — 8,731,123 — Privately issued 103 — — 103 Collateralized debt obligations 50,316 — — 50,316 Other debt securities 121,488 — 121,488 — Equity securities 83,757 64,841 18,916 — 9,156,932 64,841 9,041,672 50,419 Real estate loans held for sale 742,249 — 742,249 — Other assets (b) 92,129 — 74,733 17,396 Total assets $ 10,299,485 116,257 10,115,413 67,815 Trading account liabilities $ 203,464 — 203,464 — Other liabilities (b) 8,596 — 8,547 49 Total liabilities $ 212,060 — 212,011 49 (a) There were no significant transfers between Level 1 and Level 2 of the fair value hierarchy during the nine months ended September 30, 2015 and the year ended December 31, 2014. (b) Comprised predominantly of interest rate swap agreements used for interest rate risk management (Level 2), commitments to sell real estate loans (Level 2) and commitments to originate real estate loans to be held for sale (Level 3). The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the three months ended September 30, 2015 were as follows: Investment securities available for sale Privately issued mortgage-backed Collateralized Other assets (in thousands) Balance – June 30, 2015 $ 88 $ 50,483 $ 11,206 Total gains (losses) realized/unrealized: Included in earnings — — 21,709 (a) Included in other comprehensive income — (472 )(d) — Settlements (6 ) (135 ) — Transfers in and/or out of Level 3 (b) — — (15,268 )(c) 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 (a) The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the three months ended September 30, 2014 were as follows: Investment securities available for sale Privately issued mortgage-backed Collateralized Other assets (in thousands) Balance – June 30, 2014 $ 119 $ 56,200 $ 22,023 Total gains (losses) realized/unrealized: Included in earnings — — 9,657 (a) Included in other comprehensive income — 2,201 (d) — Settlements (7 ) (3,593 ) — Transfers in and/or out of Level 3 (b) — — (15,188 )(c) Balance – September 30, 2014 $ 112 $ 54,808 $ 16,492 Changes in unrealized gains included in earnings related to assets still held at September 30, 2014 $ — $ — $ 12,421 (a) 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 Collateralized Other assets (in thousands) Balance – January 1, 2015 $ 103 $ 50,316 $ 17,347 Total gains (losses) realized/unrealized: Included in earnings — — 67,611 (a) Included in other comprehensive income — 5,153 (d) — Settlements (21 ) (5,593 ) — Transfers in and/or out of Level 3 (b) — — (67,311 )(c) 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 (a) The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the nine months ended September 30, 2014 were as follows: Investment securities available for sale Privately issued mortgage-backed Collateralized Other assets (in thousands) Balance – January 1, 2014 $ 1,850 $ 63,083 $ 3,941 Total gains (losses) realized/unrealized: Included in earnings — — 63,557 (a) Included in other comprehensive income 272 (d) 11,333 (d) — Settlements (2,010 ) (19,608 ) — Transfers in and/or out of Level 3 (b) — — (51,006 )(c) Balance – September 30, 2014 $ 112 $ 54,808 $ 16,492 Changes in unrealized gains included in earnings related to assets still held at September 30, 2014 $ — $ — $ 17,773 (a) (a) Reported as mortgage banking revenues in the consolidated statement of income and includes the fair value of commitment issuances and expirations. (b) 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. (c) Transfers out of Level 3 consist of interest rate locks transferred to closed loans. (d) Reported as net unrealized gains (losses) on investment securities in the consolidated statement of comprehensive income. 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 10% to 90% at September 30, 2015. As these discounts are not readily observable and are considered significant, the valuations have been classified as Level 3. Loans subject to nonrecurring fair value measurement were $177 million at September 30, 2015 ($106 million and $71 million of which were classified as Level 2 and Level 3, respectively), $173 million at December 31, 2014 ($94 million and $79 million of which were classified as Level 2 and Level 3, respectively) and $196 million at September 30, 2014 ($112 million and $84 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, 2015 were decreases of $11 million and $53 million for the three- and nine-month periods ended September 30, 2015, 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, 2014 were decreases of $23 million and $46 million for the three- and nine-month periods ended September 30, 2014, 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 $15 million and $21 million at September 30, 2015 and September 30, 2014, 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, 2015 and 2014. Significant unobservable inputs to Level 3 measurements The following tables present quantitative information about significant unobservable inputs used in the fair value measurements for Level 3 assets and liabilities at September 30, 2015 and December 31, 2014: Fair value at Valuation Unobservable Range (in thousands) Recurring fair value measurements Privately issued mortgage–backed securities $ 82 Two independent — — Collateralized debt obligations 49,876 Discounted cash flow Probability of default 12%-57% (33%) Loss severity 100% Net other assets (liabilities)(a) 17,647 Discounted cash flow Commitment 0%-66% (38%) Fair value at Valuation Unobservable Range (in thousands) Recurring fair value measurements Privately issued mortgage–backed securities $ 103 Two independent — — Collateralized debt obligations 50,316 Discounted cash flow Probability of default 12%-57% (36%) Loss severity 100% Net other assets (liabilities)(a) 17,347 Discounted cash flow Commitment 0%-96% (17%) (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. 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, 2015 Carrying Estimated Level 1 Level 2 Level 3 (in thousands) Financial assets: Cash and cash equivalents $ 1,249,704 $ 1,249,704 $ 1,193,831 $ 55,873 $ — Interest-bearing deposits at banks 4,713,266 4,713,266 — 4,713,266 — Trading account assets 340,710 340,710 48,006 292,704 — Investment securities 14,494,539 14,521,740 40,370 14,283,075 198,295 Loans and leases: Commercial loans and leases 20,233,177 19,920,031 — — 19,920,031 Commercial real estate loans 28,720,537 28,633,973 — 71,357 28,562,616 Residential real estate loans 8,211,062 8,302,630 — 4,918,613 3,384,017 Consumer loans 11,375,472 11,280,973 — — 11,280,973 Allowance for credit losses (933,798 ) — — — — Loans and leases, net 67,606,450 68,137,607 — 4,989,970 63,147,637 Accrued interest receivable 242,935 242,935 — 242,935 — Financial liabilities: Noninterest-bearing deposits $ (28,189,330 ) $ (28,189,330 ) $ — $ (28,189,330 ) $ — Savings deposits and NOW accounts (41,757,661 ) (41,757,661 ) — (41,757,661 ) — Time deposits (2,791,367 ) (2,810,224 ) — (2,810,224 ) — Deposits at Cayman Islands office (206,185 ) (206,185 ) — (206,185 ) — Short-term borrowings (173,783 ) (173,783 ) — (173,783 ) — Long-term borrowings (10,174,289 ) (10,219,180 ) — (10,219,180 ) — Accrued interest payable (73,475 ) (73,475 ) — (73,475 ) — Trading account liabilities (233,006 ) (233,006 ) — (233,006 ) — Other financial instruments: Commitments to originate real estate loans for sale $ 17,647 $ 17,647 $ — $ — $ 17,647 Commitments to sell real estate loans (8,379 ) (8,379 ) — (8,379 ) — Other credit-related commitments (118,656 ) (118,656 ) — — (118,656 ) Interest rate swap agreements used for interest rate risk management 60,782 60,782 — 60,782 — December 31, 2014 Carrying Estimated Level 1 Level 2 Level 3 (in thousands) Financial assets: Cash and cash equivalents $ 1,373,357 $ 1,373,357 $ 1,296,923 $ 76,434 $ — Interest-bearing deposits at banks 6,470,867 6,470,867 — 6,470,867 — Trading account assets 308,175 308,175 51,416 256,759 — Investment securities 12,993,542 13,023,956 64,841 12,750,396 208,719 Loans and leases: Commercial loans and leases 19,461,292 19,188,574 — — 19,188,574 Commercial real estate loans 27,567,569 27,487,818 — 307,667 27,180,151 Residential real estate loans 8,657,301 8,729,056 — 5,189,086 3,539,970 Consumer loans 10,982,794 10,909,623 — — 10,909,623 Allowance for credit losses (919,562 ) — — — — Loans and leases, net 65,749,394 66,315,071 — 5,496,753 60,818,318 Accrued interest receivable 227,348 227,348 — 227,348 — Financial liabilities: Noninterest-bearing deposits $ (26,947,880 ) $ (26,947,880 ) $ — $ (26,947,880 ) $ — Savings deposits and NOW accounts (43,393,618 ) (43,393,618 ) — (43,393,618 ) — Time deposits (3,063,973 ) (3,086,126 ) — (3,086,126 ) — Deposits at Cayman Islands office (176,582 ) (176,582 ) — (176,582 ) — Short-term borrowings (192,676 ) (192,676 ) — (192,676 ) — Long-term borrowings (9,006,959 ) (9,139,789 ) — (9,139,789 ) — Accrued interest payable (63,372 ) (63,372 ) — (63,372 ) — Trading account liabilities (203,464 ) (203,464 ) — (203,464 ) — Other financial instruments: Commitments to originate real estate loans for sale $ 17,347 $ 17,347 $ — $ — $ 17,347 Commitments to sell real estate loans (7,065 ) (7,065 ) — (7,065 ) — Other credit-related commitments (119,079 ) (119,079 ) — — (119,079 ) Interest rate swap agreements used for interest rate risk management 73,251 73,251 — 73,251 — 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. 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 NOW accounts 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, 2015
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, 2015 2014 (in thousands) Commitments to extend credit Home equity lines of credit $ 5,535,704 6,194,516 Commercial real estate loans to be sold 89,374 212,257 Other commercial real estate and construction 5,356,256 4,834,699 Residential real estate loans to be sold 587,206 432,352 Other residential real estate 674,338 524,399 Commercial and other 12,144,962 11,080,856 Standby letters of credit 3,441,337 3,706,888 Commercial letters of credit 44,082 46,965 Financial guarantees and indemnification contracts 2,922,743 2,490,050 Commitments to sell real estate loans 977,822 1,237,294 Commitments to extend credit are agreements to lend to customers, generally having fixed expiration dates or other termination clauses that may require payment of a fee. Standby and commercial letters of credit are conditional commitments issued to guarantee the performance of a customer to a third party. Standby letters of credit generally are contingent upon the failure of the customer to perform according to the terms of the underlying contract with the third party, whereas commercial letters of credit are issued to facilitate commerce and typically result in the commitment being funded when the underlying transaction is consummated between the customer and a third party. The credit risk associated with commitments to extend credit and standby and commercial letters of credit is essentially the same as that involved with extending loans to customers and is subject to normal credit policies. Collateral may be obtained based on management’s assessment of the customer’s creditworthiness. Financial guarantees and indemnification contracts are oftentimes similar to standby letters of credit and include mandatory purchase agreements issued to ensure that customer obligations are fulfilled, recourse obligations associated with sold loans, and other guarantees of customer performance or compliance with designated rules and regulations. Included in financial guarantees and indemnification contracts are loan principal amounts sold with recourse in conjunction with the Company’s involvement in the Fannie Mae Delegated Underwriting and Servicing program. The Company’s maximum credit risk for recourse associated with loans sold under this program totaled approximately $2.5 billion and $2.4 billion at September 30, 2015 and December 31, 2014, 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. Subject to the outcome of the matter discussed in the following paragraph, at September 30, 2015, management believes that any further liability arising out of the Company’s obligation to loan purchasers is not material to the Company’s consolidated financial position. The Company is the subject of an investigation by government agencies relating to the origination of Federal Housing Administration (“FHA”) insured residential home loans and residential home loans sold to The Federal Home Loan Mortgage Corporation (“Freddie Mac”) and The Federal National Mortgage Association (“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”) are investigating whether the Company complied with underwriting guidelines concerning certain loans where HUD paid FHA insurance claims. The Company is fully cooperating with the investigation. The Government has 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 do not meet underwriting guidelines. The Company, based on its own review of the sample, does 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 concerns whether the mortgages sold to Freddie Mac and Fannie Mae comply with applicable underwriting guidelines. The Company is also cooperating with that portion of the investigation. The investigation could lead to claims by the Government under the False Claims Act and the Financial Institutions Reform, Recovery, and Enforcement Act of 1989, which allow treble and other special damages substantially in excess of actual losses. Remedies in these proceedings or settlements may include restitution, fines, penalties, or alterations in the Company’s business practices. The Company and the Government continue settlement discussions regarding the investigation. 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, 2015
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 to the Company’s consolidated financial statements as of and for the year ended December 31, 2014. 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. Effective January 1, 2015, the Company made certain changes to its methodology for measuring segment profit and loss. Those changes in the measurement of segment profitability were largely the result of updated funds transfer pricing and various cost allocation reviews. The most significant changes to the funds transfer pricing resulted from ascribing a longer duration to non-maturity deposits, which significantly benefitted the Retail Banking segment. The cost allocation review having the largest impact related to a branch cost study. That study consisted of transaction reviews and time studies which resulted in a higher cost allocation from the Retail Banking segment to the Business Banking segment. In addition, effective July 1, 2015, the Company changed its internal profitability reporting to move a builder and developer lending unit from the Residential Mortgage Banking segment to the Commercial Real Estate segment. Accordingly, financial information presented herein for the periods prior to July 1, 2015 has been reclassified to conform to the current presentation. Total revenues and net income decreased in the Residential Banking segment and increased in the Commercial Real Estate segment for the three months ended September 30, 2014 by $5 million and $2 million, respectively, and for the nine months ended September 30, 2014 by $13 million and $5 million, respectively. The impact of the change to total revenues and net income for the second quarter of 2015 was $6 million and $3 million, respectively, and for the first half of 2015 was $12 million and $5 million, respectively. Prior period financial information has been restated to reflect the changes noted to provide segment information on a comparable basis, as noted in the following tables. Three months ended September 30, 2014 Net income (loss) as Impact of Net income (loss) (in thousands) Business Banking $ 30,905 (5,867 ) 25,038 Commercial Banking 101,740 (1,035 ) 100,705 Commercial Real Estate 78,581 95 78,676 Discretionary Portfolio 8,279 4,216 12,495 Residential Mortgage Banking 25,021 (2,272 ) 22,749 Retail Banking 32,901 39,156 72,057 All Other (2,083 ) (34,293 ) (36,376 ) Total $ 275,344 — 275,344 Nine months ended September 30, 2014 Net income (loss) as Impact of Net income (loss) (in thousands) Business Banking $ 87,263 (13,500 ) 73,763 Commercial Banking 306,863 (3,226 ) 303,637 Commercial Real Estate 230,668 (414 ) 230,254 Discretionary Portfolio 34,538 4,360 38,898 Residential Mortgage Banking 72,144 (7,464 ) 64,680 Retail Banking 94,646 119,418 214,064 All Other (37,425 ) (99,174 ) (136,599 ) Total $ 788,697 — 788,697 As also described in note 22 to the Company’s 2014 consolidated financial statements, neither goodwill nor core deposit and other intangible assets (and the amortization charges associated with such assets) resulting from acquisitions of financial institutions have been allocated to the Company’s reportable segments, but are included in the “All Other” category. The Company does, however, assign such intangible assets to business units for purposes of testing for impairment. Information about the Company’s segments is presented in the following table: Three months ended September 30 2015 2014 Total Inter- Net Total Inter- Net (in thousands) Business Banking $ 112,650 1,167 23,995 $ 113,425 1,082 25,038 Commercial Banking 270,554 1,097 108,422 247,282 1,281 100,705 Commercial Real Estate 181,478 469 85,312 170,772 442 78,676 Discretionary Portfolio 13,773 (5,365 ) 5,113 24,835 (5,478 ) 12,495 Residential Mortgage Banking 99,518 12,918 21,150 104,092 12,875 22,749 Retail Banking 308,520 3,292 64,721 316,052 3,735 72,057 All Other 146,033 (13,578 ) (28,312 ) 143,712 (13,937 ) (36,376 ) Total $ 1,132,526 — 280,401 $ 1,120,170 — 275,344 Nine months ended September 30 2015 2014 Total Inter- Net Total Inter- Net (in thousands) Business Banking $ 332,341 3,334 74,160 337,929 3,359 73,763 Commercial Banking 774,392 3,281 312,926 748,978 3,834 303,637 Commercial Real Estate 535,909 978 250,501 500,814 1,315 230,254 Discretionary Portfolio 49,724 (16,184 ) 21,823 79,404 (15,799 ) 38,898 Residential Mortgage Banking 310,843 36,741 75,462 299,237 34,395 64,680 Retail Banking 914,484 9,688 202,415 934,386 11,137 214,064 All Other 494,779 (37,838 ) (128,585 ) 421,488 (38,241 ) (136,599 ) Total $ 3,412,472 — 808,702 3,322,236 — 788,697 Average total assets (b) Nine months ended September 30 Year ended December 31 2015 2014 2014 (in millions) Business Banking $ 5,321 5,287 5,281 Commercial Banking 24,041 22,805 22,892 Commercial Real Estate 18,632 17,187 17,370 Discretionary Portfolio 23,153 20,306 20,798 Residential Mortgage Banking 3,007 3,016 3,076 Retail Banking 10,912 10,348 10,449 All Other 12,279 11,003 12,277 Total $ 97,345 89,952 92,143 (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 $6,248,000 and $5,841,000 for the three-month periods ended September 30, 2015 and 2014, respectively, and $18,106,000 and $17,635,000 for the nine-month periods ended September 30, 2015 and 2014, 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. (b) Average assets of the Commercial Real Estate and Residential Mortgage Banking segments for the nine months ended September 30, 2014 and the year ended December 31, 2014 differ by $246 million and $257 million, respectively, from the previously reported balances reflecting the change in the Company’s internal profitability reporting for a builder and developer lending unit which moved assets held by that unit from the Residential Mortgage Banking Segment to the Commercial Real Estate Segment.

Relationship with Bayview Lendi

Relationship with Bayview Lending Group LLC and Bayview Financial Holdings, L.P.	9 Months Ended
	Sep. 30, 2015
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 $33 million at September 30, 2015. 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 $4.3 billion and $4.8 billion at September 30, 2015 and December 31, 2014, respectively. Revenues from those servicing rights were $6 million for each of the quarters ended September 30, 2015 and 2014, respectively, and $17 million and $20 million for the nine months ended September 30, 2015 and 2014, respectively. The Company sub-services residential real estate loans for Bayview Financial having outstanding principal balances totaling $39.5 billion and $41.3 billion at September 30, 2015 and December 31, 2014, respectively. Revenues earned for sub-servicing loans for Bayview Financial were $26 million and $29 million for the three-month periods ended September 30, 2015 and 2014, respectively, and $91 million and $82 million for the nine-month periods ended September 30, 2015 and 2014, respectively. In addition, the Company held $187 million and $202 million of mortgage-backed securities in its held-to-maturity portfolio at September 30, 2015 and December 31, 2014, respectively, that were securitized by Bayview Financial.

Sale of trust accounts

Sale of trust accounts	9 Months Ended
	Sep. 30, 2015
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; $8 million and $26 million during the three months and nine months ended September 30, 2014, respectively; and $34 million during the year ended December 31, 2014. After considering related expenses, net income attributable to the business that was sold was not material to the consolidated results of operations of the Company in any of those periods.

Significant accounting polici25

Significant accounting policies (Policies)	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Consolidation	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 the 2014 Annual Report. Additionally, effective January 1, 2015 the Company made an accounting policy election in accordance with amended accounting guidance issued by the Financial Accounting Standards Board in January 2014 to account for investments in qualified affordable housing projects using the proportional amortization method. Under the proportional amortization method, the Company amortizes the initial cost of the investment in proportion to the tax credits and other tax benefits received and recognizes the net investment performance in the income statement as a component of income tax expense. The adoption of the amended guidance did not have a significant effect on the Company’s financial position or results of operations, but did result in the restatement of the consolidated statement of income for the three months and nine months ended September 30, 2014 to remove $14 million and $39 million, respectively, of losses associated with qualified affordable housing projects from “other costs of operations” and include the amortization of the initial cost of the investment in income tax expense. The cumulative effect adjustment associated with adopting the amended guidance was not material as of the beginning of any period presented in these consolidated financial statements. See note 11 for information regarding the Company’s investments in qualified affordable housing projects. In the opinion of management, all adjustments necessary for a fair presentation have been made and, except as described above, were all of a normal recurring nature.

Investment securities (Tables)

Investment securities (Tables)	9 Months Ended
	Sep. 30, 2015
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 Gross Gross Estimated (in thousands) September 30, 2015 Investment securities available for sale: U.S. Treasury and federal agencies $ 197,764 1,630 — $ 199,394 Obligations of states and political subdivisions 6,174 170 48 6,296 Mortgage-backed securities: Government issued or guaranteed 10,504,756 228,333 19,041 10,714,048 Privately issued 82 2 2 82 Collateralized debt obligations 28,467 22,465 1,056 49,876 Other debt securities 136,793 1,650 17,975 120,468 Equity securities 49,198 20,360 213 69,345 10,923,234 274,610 38,335 11,159,509 Investment securities held to maturity: Obligations of states and political subdivisions 125,251 1,395 347 126,299 Mortgage-backed securities: Government issued or guaranteed 2,679,546 69,486 4,787 2,744,245 Privately issued 186,883 1,628 40,174 148,337 Other debt securities 6,806 — — 6,806 2,998,486 72,509 45,308 3,025,687 Other securities 336,544 — — 336,544 Total $ 14,258,264 347,119 83,643 $ 14,521,740 Amortized Gross Gross Estimated (in thousands) December 31, 2014 Investment securities available for sale: U.S. Treasury and federal agencies $ 161,408 544 5 $ 161,947 Obligations of states and political subdivisions 8,027 224 53 8,198 Mortgage-backed securities: Government issued or guaranteed 8,507,571 223,889 337 8,731,123 Privately issued 104 2 3 103 Collateralized debt obligations 30,073 21,276 1,033 50,316 Other debt securities 138,240 1,896 18,648 121,488 Equity securities 73,901 11,020 1,164 83,757 8,919,324 258,851 21,243 9,156,932 Investment securities held to maturity: Obligations of states and political subdivisions 148,961 2,551 189 151,323 Mortgage-backed securities: Government issued or guaranteed 3,149,320 78,485 7,000 3,220,805 Privately issued 201,733 1,143 44,576 158,300 Other debt securities 7,854 — — 7,854 3,507,868 82,179 51,765 3,538,282 Other securities 328,742 — — 328,742 Total $ 12,755,934 341,030 73,008 $ 13,023,956
Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity	At September 30, 2015, the amortized cost and estimated fair value of debt securities by contractual maturity were as follows: Amortized Estimated (in thousands) Debt securities available for sale: Due in one year or less $ 8,282 8,330 Due after one year through five years 197,796 199,712 Due after five years through ten years 3,296 3,495 Due after ten years 159,824 164,497 369,198 376,034 Mortgage-backed securities available for sale 10,504,838 10,714,130 $ 10,874,036 11,090,164 Debt securities held to maturity: Due in one year or less $ 30,523 30,706 Due after one year through five years 74,511 75,150 Due after five years through ten years 20,217 20,443 Due after ten years 6,806 6,806 132,057 133,105 Mortgage-backed securities held to maturity 2,866,429 2,892,582 $ 2,998,486 3,025,687
Investment Securities in Continuous Unrealized Loss Position	A summary of investment securities that as of September 30, 2015 and December 31, 2014 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 Fair value Unrealized (in thousands) September 30, 2015 Investment securities available for sale: Obligations of states and political subdivisions $ 516 (2 ) 1,405 (46 ) Mortgage-backed securities: Government issued or guaranteed 1,942,135 (18,925 ) 5,503 (116 ) Privately issued — — 48 (2 ) Collateralized debt obligations 5,733 (324 ) 2,155 (732 ) Other debt securities 19,335 (458 ) 86,813 (17,517 ) Equity securities — — 212 (213 ) 1,967,719 (19,709 ) 96,136 (18,626 ) Investment securities held to maturity: Obligations of states and political subdivisions 37,336 (292 ) 4,096 (55 ) Mortgage-backed securities: Government issued or guaranteed 16,619 (129 ) 240,730 (4,658 ) Privately issued — — 118,840 (40,174 ) 53,955 (421 ) 363,666 (44,887 ) Total $ 2,021,674 (20,130 ) 459,802 (63,513 ) December 31, 2014 Investment securities available for sale: U.S. Treasury and federal agencies $ 6,505 (5 ) — — Obligations of states and political subdivisions 1,785 (52 ) 121 (1 ) Mortgage-backed securities: Government issued or guaranteed 39,001 (186 ) 5,555 (151 ) Privately issued — — 65 (3 ) Collateralized debt obligations 2,108 (696 ) 5,512 (337 ) Other debt securities 14,017 (556 ) 92,661 (18,092 ) Equity securities 2,138 (1,164 ) — — 65,554 (2,659 ) 103,914 (18,584 ) Investment securities held to maturity: Obligations of states and political subdivisions 29,886 (184 ) 268 (5 ) Mortgage-backed securities: Government issued or guaranteed 137,413 (361 ) 446,780 (6,639 ) Privately issued — — 127,512 (44,576 ) 167,299 (545 ) 574,560 (51,220 ) Total $ 232,853 (3,204 ) 678,474 (69,804 )

Loans and leases and the allo27

Loans and leases and the allowance for credit losses (Tables)	9 Months Ended
	Sep. 30, 2015
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 acquired loans that were recorded at fair value at the acquisition date and included in the consolidated balance sheet follow: September 30, December 31, 2015 2014 (in thousands) Outstanding principal balance $ 2,410,454 3,070,268 Carrying amount: Commercial, financial, leasing, etc. 103,583 247,820 Commercial real estate 728,376 961,828 Residential real estate 385,885 453,360 Consumer 812,117 933,537 $ 2,029,961 2,596,545
Summary of Changes in Accretable Yield for Acquired Loans	A summary of changes in the accretable yield for acquired loans for the three months and nine months ended September 30, 2015 and 2014 follows: Three months ended September 30 2015 2014 Purchased Other Purchased Other impaired acquired impaired acquired (in thousands) Balance at beginning of period $ 77,624 344,989 $ 26,082 450,970 Interest income (5,865 ) (37,396 ) (4,149 ) (39,019 ) Reclassifications from nonaccretable balance 47 769 129 9,673 Other (a) — 4,697 — 1,870 Balance at end of period $ 71,806 313,059 $ 22,062 423,494 Nine months ended September 30 2015 2014 Purchased Other Purchased Other impaired acquired impaired acquired (in thousands) Balance at beginning of period $ 76,518 397,379 $ 37,230 538,633 Interest income (16,843 ) (118,697 ) (15,583 ) (135,105 ) Reclassifications from nonaccretable balance 12,131 27,792 415 10,448 Other (a) — 6,585 — 9,518 Balance at end of period $ 71,806 313,059 $ 22,062 423,494 (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, 2015 and December 31, 2014 follows: 30-89 90 Days or Purchased Nonaccrual Total Current Non- Acquired (in thousands) September 30, 2015 Commercial, financial, leasing, etc. $ 19,965,307 29,451 5,882 3,477 4,645 224,415 $ 20,233,177 Real estate: Commercial 23,184,906 105,140 21,629 17,906 45,523 176,491 23,551,595 Residential builder and developer 1,479,659 15,951 — 7,488 65,102 46,022 1,614,222 Other commercial construction 3,493,349 28,433 1,373 1,769 17,484 12,312 3,554,720 Residential 7,323,813 206,044 194,280 16,295 14,392 153,354 7,908,178 Residential Alt-A 226,871 11,662 — — — 64,351 302,884 Consumer: Home equity lines and loans 5,710,632 38,506 — 15,454 2,275 78,126 5,844,993 Automobile 2,319,556 36,867 — 53 — 13,892 2,370,368 Other 3,084,080 31,210 8,301 18,385 — 18,135 3,160,111 Total $ 66,788,173 503,264 231,465 80,827 149,421 787,098 $ 68,540,248 Current 30-89 90 Days or Purchased Nonaccrual Total Non- Acquired (in thousands) December 31, 2014 Commercial, financial, leasing, etc. $ 19,228,265 37,246 1,805 6,231 10,300 177,445 $ 19,461,292 Real estate: Commercial 22,208,491 118,704 22,170 14,662 51,312 141,600 22,556,939 Residential builder and developer 1,273,607 11,827 492 9,350 98,347 71,517 1,465,140 Other commercial construction 3,484,932 17,678 — — 17,181 25,699 3,545,490 Residential 7,640,368 226,932 216,489 35,726 18,223 180,275 8,318,013 Residential Alt-A 249,810 11,774 — — — 77,704 339,288 Consumer: Home equity lines and loans 5,859,378 42,945 — 27,896 2,374 89,291 6,021,884 Automobile 1,931,138 30,500 — 133 — 17,578 1,979,349 Other 2,909,791 33,295 4,064 16,369 — 18,042 2,981,561 Total $ 64,785,780 530,901 245,020 110,367 197,737 799,151 $ 66,668,956 (a) Acquired loans that were recorded at fair value at acquisition date. This category does not include purchased impaired loans that are presented separately. (b) Accruing loans that were impaired at acquisition date and were recorded at fair value.
Changes in Allowance for Credit Losses	Changes in the allowance for credit losses for the three months ended September 30, 2015 were as follows: Commercial, Real Estate 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 three months ended September 30, 2014 were as follows: Commercial, Real Estate Commercial Residential Consumer Unallocated Total (in thousands) Beginning balance $ 292,251 311,254 72,404 165,871 75,886 $ 917,666 Provision for credit losses 2,373 8,046 (3,187 ) 21,815 (47 ) 29,000 Net charge-offs Charge-offs (15,921 ) (1,666 ) (4,193 ) (21,312 ) — (43,092 ) Recoveries 7,849 1,267 2,498 3,445 — 15,059 Net charge-offs (8,072 ) (399 ) (1,695 ) (17,867 ) — (28,033 ) Ending balance $ 286,552 318,901 67,522 169,819 75,839 $ 918,633 Changes in the allowance for credit losses for the nine months ended September 30, 2015 were as follows: Commercial, Real Estate 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 Changes in the allowance for credit losses for the nine months ended September 30, 2014 were as follows: Commercial, Real Estate Commercial Residential Consumer Unallocated Total (in thousands) Beginning balance $ 273,383 324,978 78,656 164,644 75,015 $ 916,676 Provision for credit losses 40,527 (4,067 ) (916 ) 54,632 824 91,000 Net charge-offs Charge-offs (44,872 ) (7,966 ) (17,124 ) (62,407 ) — (132,369 ) Recoveries 17,514 5,956 6,906 12,950 — 43,326 Net charge-offs (27,358 ) (2,010 ) (10,218 ) (49,457 ) — (89,043 ) Ending balance $ 286,552 318,901 67,522 169,819 75,839 $ 918,633
Impaired Loans and Leases	Information with respect to loans and leases that were considered impaired follows. September 30, 2015 December 31, 2014 Recorded Unpaid Related Recorded Unpaid Related (in thousands) With an allowance recorded: Commercial, financial, leasing, etc. $ 144,051 166,877 35,195 132,340 165,146 31,779 Real estate: Commercial 105,561 122,369 18,932 83,955 96,209 14,121 Residential builder and developer 6,544 10,276 788 17,632 22,044 805 Other commercial construction 2,445 3,991 391 5,480 6,484 900 Residential 83,349 101,367 4,775 88,970 107,343 4,296 Residential Alt-A 93,168 107,075 8,500 101,137 114,565 11,000 Consumer: Home equity lines and loans 23,257 24,239 3,541 19,771 20,806 6,213 Automobile 23,985 23,985 5,118 30,317 30,317 8,070 Other 18,870 18,870 5,486 18,973 18,973 5,459 501,230 579,049 82,726 498,575 581,887 82,643 With no related allowance recorded: Commercial, financial, leasing, etc. 111,023 133,100 — 73,978 81,493 — Real estate: Commercial 77,147 84,677 — 66,777 78,943 — Residential builder and developer 42,800 68,906 — 58,820 96,722 — Other commercial construction 10,307 28,480 — 20,738 41,035 — Residential 16,232 26,626 — 16,815 26,750 — Residential Alt-A 20,891 35,836 — 26,752 46,964 — 278,400 377,625 — 263,880 371,907 — Total: Commercial, financial, leasing, etc. 255,074 299,977 35,195 206,318 246,639 31,779 Real estate: Commercial 182,708 207,046 18,932 150,732 175,152 14,121 Residential builder and developer 49,344 79,182 788 76,452 118,766 805 Other commercial construction 12,752 32,471 391 26,218 47,519 900 Residential 99,581 127,993 4,775 105,785 134,093 4,296 Residential Alt-A 114,059 142,911 8,500 127,889 161,529 11,000 Consumer: Home equity lines and loans 23,257 24,239 3,541 19,771 20,806 6,213 Automobile 23,985 23,985 5,118 30,317 30,317 8,070 Other 18,870 18,870 5,486 18,973 18,973 5,459 Total $ 779,630 956,674 82,726 762,455 953,794 82,643
Interest Income Recognized on Impaired Loans	Three months ended Three months ended Interest income Interest income Average Total Cash Average Total Cash (in thousands) Commercial, financial, leasing, etc. $ 242,157 1,017 1,017 228,749 611 611 Real estate: Commercial 179,327 2,327 2,327 189,952 821 821 Residential builder and developer 53,009 81 81 90,493 18 18 Other commercial construction 17,236 1,943 1,943 58,500 251 251 Residential 99,939 1,835 1,316 104,516 1,328 776 Residential Alt-A 116,191 1,539 618 131,574 1,643 681 Consumer: Home equity lines and loans 21,952 231 66 19,268 219 81 Automobile 24,429 391 39 33,666 528 67 Other 19,238 188 23 18,677 177 44 Total $ 773,478 9,552 7,430 875,395 5,596 3,350 Nine months ended Nine months ended Interest income Interest income Average Total Cash Average Total Cash (in thousands) Commercial, financial, leasing, etc. $ 226,243 2,123 2,123 171,227 1,379 1,379 Real estate: Commercial 161,834 4,433 4,433 194,337 2,616 2,616 Residential builder and developer 64,165 275 275 94,453 131 131 Other commercial construction 22,130 2,166 2,166 74,531 1,694 1,694 Residential 101,997 4,639 3,011 132,606 7,784 6,146 Residential Alt-A 120,710 4,799 1,962 135,374 5,002 1,900 Consumer: Home equity lines and loans 20,619 656 179 17,902 540 182 Automobile 26,521 1,257 136 36,560 1,742 228 Other 19,053 547 86 18,229 517 145 Total $ 763,272 20,895 14,371 875,219 21,405 14,421
Summary of Loan Grades	The following table summarizes the loan grades applied to the various classes of the Company’s commercial loans and commercial real estate loans. Real Estate Commercial, Residential Other Financial, Builder and Commercial Leasing, etc. Commercial Developer Construction (in thousands) September 30, 2015 Pass $ 19,223,102 22,479,501 1,507,057 3,447,841 Criticized accrual 785,660 895,603 61,143 94,567 Criticized nonaccrual 224,415 176,491 46,022 12,312 Total $ 20,233,177 23,551,595 1,614,222 3,554,720 December 31, 2014 Pass $ 18,695,440 21,837,022 1,347,778 3,347,522 Criticized accrual 588,407 578,317 45,845 172,269 Criticized nonaccrual 177,445 141,600 71,517 25,699 Total $ 19,461,292 22,556,939 1,465,140 3,545,490
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, 2015 Individually evaluated for impairment $ 35,195 19,743 13,275 14,145 $ 82,358 Collectively evaluated for impairment 250,271 292,214 39,804 186,706 768,995 Purchased impaired 1,201 1,132 1,917 1,463 5,713 Allocated $ 286,667 313,089 54,996 202,314 857,066 Unallocated 76,732 Total $ 933,798 December 31, 2014 Individually evaluated for impairment $ 31,779 15,490 14,703 19,742 $ 81,714 Collectively evaluated for impairment 251,607 291,244 45,061 165,140 753,052 Purchased impaired 4,652 1,193 2,146 1,151 9,142 Allocated $ 288,038 307,927 61,910 186,033 843,908 Unallocated 75,654 Total $ 919,562
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, 2015 Individually evaluated for impairment $ 255,074 243,743 213,640 66,112 $ 778,569 Collectively evaluated for impairment 19,973,458 28,348,685 7,983,030 11,307,085 67,612,258 Purchased impaired 4,645 128,109 14,392 2,275 149,421 Total $ 20,233,177 28,720,537 8,211,062 11,375,472 $ 68,540,248 December 31, 2014 Individually evaluated for impairment $ 206,318 252,347 232,398 69,061 $ 760,124 Collectively evaluated for impairment 19,244,674 27,148,382 8,406,680 10,911,359 65,711,095 Purchased impaired 10,300 166,840 18,223 2,374 197,737 Total $ 19,461,292 27,567,569 8,657,301 10,982,794 $ 66,668,956
Loan Modification Activities that were Considered Troubled Debt Restructurings	The tables below summarize the Company’s loan modification activities that were considered troubled debt restructurings for the three months ended September 30, 2015 and 2014: Recorded investment Financial effects of Three months ended September 30, 2015 Number Pre- Post- Recorded Interest (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 Alt-A 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. Recorded investment Financial effects of Three months ended September 30, 2014 Number Pre- Post- Recorded Interest (dollars in thousands) Commercial, financial, leasing, etc. Principal deferral 15 $ 1,305 $ 1,300 $ (5 ) $ — Real estate: Commercial Principal deferral 8 2,081 2,068 (13 ) — Other 1 650 — (650 ) — Combination of concession types 4 483 478 (5 ) (95 ) Residential builder and developer Principal deferral 1 241 241 — — Other commercial construction Principal deferral 1 145 142 (3 ) — Residential Principal deferral 3 98 97 (1 ) — Combination of concession types 8 1,100 1,136 36 (135 ) Residential Alt-A Combination of concession types 3 349 369 20 (64 ) Consumer: Home equity lines and loans Combination of concession types 5 519 519 — (67 ) Automobile Principal deferral 45 1,003 1,003 — — Interest rate reduction 3 30 30 — (2 ) Other 7 96 96 — — Combination of concession types 19 348 348 — (21 ) Other Principal deferral 6 48 48 — — Interest rate reduction 1 2 2 — — Combination of concession types 24 511 511 — (121 ) Total 154 $ 9,009 $ 8,388 $ (621 ) $ (505 ) (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, 2015 and 2014: Recorded investment Financial effects of Nine months ended September 30, 2015 Number Pre- Post- Recorded Interest (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 Alt-A 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. Recorded investment Financial effects of Nine months ended September 30, 2014 Number Pre- Post- Recorded Interest (dollars in thousands) Commercial, financial, leasing, etc. Principal deferral 66 $ 20,673 $ 20,499 $ (174 ) $ — Other 1 19,593 19,593 — — Combination of concession types 5 9,836 9,766 (70 ) (14 ) Real estate: Commercial Principal deferral 32 17,452 17,384 (68 ) — Other 1 650 — (650 ) — Interest rate reduction 1 255 252 (3 ) (48 ) Combination of concession types 6 892 940 48 (208 ) Residential builder and developer Principal deferral 2 1,639 1,639 — — Other commercial construction Principal deferral 4 6,703 6,611 (92 ) — Residential Principal deferral 19 1,842 1,926 84 — Interest rate reduction 1 98 104 6 (32 ) Other 1 188 188 — — Combination of concession types 30 4,211 4,287 76 (483 ) Residential Alt-A Principal deferral 5 828 900 72 — Combination of concession types 19 3,101 3,134 33 (345 ) Consumer: Home equity lines and loans Principal deferral 3 280 280 — — Interest rate reduction 5 341 341 — (76 ) Combination of concession types 41 4,147 4,147 — (443 ) Automobile Principal deferral 168 2,599 2,599 — — Interest rate reduction 6 90 90 — (5 ) Other 26 204 204 — — Combination of concession types 65 939 939 — (83 ) Other Principal deferral 21 141 141 — — Interest rate reduction 4 293 293 — (63 ) Other 1 45 45 — — Combination of concession types 57 1,883 1,883 — (585 ) Total 590 $ 98,923 $ 98,185 $ (738 ) $ (2,385 ) (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, 2015
Equity [Abstract]
Issued and Outstanding Preferred Stock	Issued and outstanding preferred stock of M&T as of September 30, 2015 and December 31, 2014 is presented below: Shares Carrying (dollars in thousands) Series A (a) Fixed Rate Cumulative Perpetual Preferred Stock, Series A, $1,000 liquidation preference per share 230,000 $ 230,000 Series C (a) Fixed Rate Cumulative Perpetual Preferred Stock, Series C, $1,000 liquidation preference per share 151,500 $ 151,500 Series D (b) Fixed Rate Non-Cumulative Perpetual Preferred Stock, Series D, $10,000 liquidation preference per share 50,000 $ 500,000 Series E (c) Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock Series E, $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 719,175 at September 30, 2015 and 721,490 at December 31, 2014. (b) Dividends, if declared, are paid semi-annually at a rate of 6.875% per year. The shares are redeemable in whole or in part on or after June 15, 2016. Notwithstanding M&T’s option to redeem the shares, if an event occurs such that the shares no longer qualify as Tier 1 capital, M&T may redeem all of the shares within 90 days following that occurrence. (c) Dividends, if declared, are paid semi-annually at a rate of 6.45% through February 14, 2024 and thereafter will be paid quarterly at a rate of the three-month London Interbank Offered Rate (“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 postr29

Pension plans and other postretirement benefits (Tables)	9 Months Ended
	Sep. 30, 2015
Compensation and Retirement Disclosure [Abstract]
Net Periodic Pension Expense for Defined Benefit Plans	Net periodic defined benefit cost for defined benefit plans consisted of the following: Pension benefits Other Three months ended September 30 2015 2014 2015 2014 (in thousands) Service cost $ 5,916 5,130 188 151 Interest cost on projected benefit obligation 17,754 17,290 651 695 Expected return on plan assets (23,527 ) (22,892 ) — — Amortization of prior service credit (1,501 ) (1,638 ) (340 ) (340 ) Amortization of net actuarial loss 11,207 3,624 26 — Net periodic benefit cost $ 9,849 1,514 525 506 Pension benefits Other Nine months ended September 30 2015 2014 2015 2014 (in thousands) Service cost $ 17,748 15,390 562 453 Interest cost on projected benefit obligation 53,261 51,871 1,953 2,084 Expected return on plan assets (70,578 ) (68,676 ) — — Amortization of prior service credit (4,504 ) (4,914 ) (1,019 ) (1,019 ) Amortization of net actuarial loss 33,619 10,871 79 — Net periodic benefit cost $ 29,546 4,542 1,575 1,518

Earnings per common share (Tabl

Earnings per common share (Tables)	9 Months Ended
	Sep. 30, 2015
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 2015 2014 2015 2014 (in thousands, except per share) Income available to common shareholders: Net income $ 280,401 275,344 $ 808,702 788,697 Less: Preferred stock dividends (a) (20,318 ) (20,443 ) (60,953 ) (55,560 ) Net income available to common equity 260,083 254,901 747,749 733,137 Less: Income attributable to unvested stock-based compensation awards (2,746 ) (2,996 ) (8,122 ) (8,830 ) Net income available to common shareholders $ 257,337 251,905 $ 739,627 724,307 Weighted-average shares outstanding: Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards 134,049 132,832 133,805 132,372 Less: Unvested stock-based compensation awards (1,419 ) (1,567 ) (1,458 ) (1,590 ) Weighted-average shares outstanding 132,630 131,265 132,347 130,782 Basic earnings per common share $ 1.94 1.92 $ 5.59 5.54 (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 2015 2014 2015 2014 (in thousands, except per share) Net income available to common equity $ 260,083 254,901 $ 747,749 733,137 Less: Income attributable to unvested stock-based compensation awards (2,737 ) (2,984 ) (8,093 ) (8,793 ) Net income available to common shareholders $ 257,346 251,917 $ 739,656 724,344 Adjusted weighted-average shares outstanding: Common and unvested stock-based compensation awards 134,049 132,832 133,805 132,372 Less: Unvested stock-based compensation awards (1,419 ) (1,567 ) (1,458 ) (1,590 ) Plus: Incremental shares from assumed conversion of stock-based compensation awards and warrants to purchase common stock 746 863 742 916 Adjusted weighted-average shares outstanding 133,376 132,128 133,089 131,698 Diluted earnings per common share $ 1.93 1.91 $ 5.56 5.50

Comprehensive income (Tables)

Comprehensive income (Tables)	9 Months Ended
	Sep. 30, 2015
Equity [Abstract]
Components of Other Comprehensive Income (Loss) and Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) to Net Income	The following table displays the components of other comprehensive income (loss) and amounts reclassified from accumulated other comprehensive income (loss) to net income: Investment Securities With All Defined Other Total Income Net (in thousands) Balance – January 1, 2015 $ 7,438 201,828 (503,027 ) (4,082 ) $ (297,843 ) 116,849 $ (180,994 ) Other comprehensive income before reclassifications: Unrealized holding gains (losses), net 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 held-to-maturity (“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 ) Investment Securities With All Defined Other Total Income Net (in thousands) Balance – January 1, 2014 $ 37,255 18,450 (161,617 ) 115 $ (105,797 ) 41,638 $ (64,159 ) Other comprehensive income before reclassifications: Unrealized holding gains, net 12,038 109,263 — — 121,301 (47,615 ) 73,686 Foreign currency translation adjustment — — — (2,314 ) (2,314 ) 810 (1,504 ) Unrealized losses on cash flow hedges — — — (162 ) (162 ) 64 (98 ) Total other comprehensive income before reclassifications 12,038 109,263 — (2,476 ) 118,825 (46,741 ) 72,084 Amounts reclassified from accumulated other comprehensive income that (increase) decrease net income: Accretion of unrealized holding losses on HTM securities 1 2,539 — — 2,540 (b) (997 ) 1,543 Amortization of prior service credit — — (5,933 ) — (5,933 )(e) 2,328 (3,605 ) Amortization of actuarial losses — — 10,871 — 10,871 (e) (4,267 ) 6,604 Total reclassifications 1 2,539 4,938 — 7,478 (2,936 ) 4,542 Total gain (loss) during the period 12,039 111,802 4,938 (2,476 ) 126,303 (49,677 ) 76,626 Balance – September 30, 2014 $ 49,294 130,252 (156,679 ) (2,361 ) $ 20,506 (8,039 ) $ 12,467 (a) Other-than-temporary impairment (b) Included in interest income (c) Included in 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 With OTTI All other plans Other Total (in thousands) Balance – December 31, 2014 $ 4,518 122,683 (305,589 ) (2,606 ) $ (180,994 ) Net gain (loss) during period 5,926 (4,873 ) 16,166 302 17,521 Balance – September 30, 2015 $ 10,444 117,810 (289,423 ) (2,304 ) $ (163,473 )

Derivative financial instrume32

Derivative financial instruments (Tables)	9 Months Ended
	Sep. 30, 2015
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- Fixed Variable (in thousands) (in years) September 30, 2015 Fair value hedges: Fixed rate long-term borrowings (a) $ 1,400,000 1.9 4.42 % 1.29 % December 31, 2014 Fair value hedges: Fixed rate long-term borrowings (a) $ 1,400,000 2.7 4.42 % 1.19 % (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, December 31, September 30, December 31, (in thousands) Derivatives designated and qualifying as hedging instruments Fair value hedges: Interest rate swap agreements (a) $ 60,782 73,251 $ — — Commitments to sell real estate loans (a) 899 728 5,142 4,217 61,681 73,979 5,142 4,217 Derivatives not designated and qualifying as hedging instruments Mortgage-related commitments to originate real estate loans for sale (a) 17,832 17,396 185 49 Commitments to sell real estate loans (a) 26 754 4,162 4,330 Trading: Interest rate contracts (b) 268,332 215,614 221,626 173,513 Foreign exchange and other option and futures contracts (b) 13,404 31,112 11,380 29,950 299,594 264,876 237,353 207,842 Total derivatives $ 361,275 338,855 $ 242,495 212,059 (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 Three months ended Derivative Hedged item Derivative Hedged item (in thousands) Derivatives in fair value hedging relationships Interest rate swap agreements: Fixed rate long-term borrowings (a) $ (2,719 ) 2,382 $ (16,792 ) 16,380 Derivatives not designated as hedging instruments Trading: Interest rate contracts (b) $ 4,120 $ 132 Foreign exchange and other option and futures contracts (b) 2,441 (781 ) Total $ 6,561 $ (649 ) Amount of gain (loss) recognized Nine months ended Nine months ended Derivative Hedged item Derivative Hedged item (in thousands) Derivatives in fair value hedging relationships Interest rate swap agreements: Fixed rate long-term borrowings (a) $ (12,469 ) 11,495 $ (26,627 ) 25,658 Derivatives not designated as hedging instruments Trading: Interest rate contracts (b) $ 6,552 $ 1,214 Foreign exchange and other option and futures contracts (b) 1,563 (6,597 ) Total $ 8,115 $ (5,383 )

Fair value measurements (Tables

Fair value measurements (Tables)	9 Months Ended
	Sep. 30, 2015
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, 2015 and December 31, 2014 measured at estimated fair value on a recurring basis: Fair value Level 1 (a) Level 2 (a) Level 3 (in thousands) Trading account assets $ 340,710 48,006 292,704 — Investment securities available for sale: U.S. Treasury and federal agencies 199,394 — 199,394 — Obligations of states and political subdivisions 6,296 — 6,296 — Mortgage-backed securities: Government issued or guaranteed 10,714,048 — 10,714,048 — Privately issued 82 — — 82 Collateralized debt obligations 49,876 — — 49,876 Other debt securities 120,468 — 120,468 — Equity securities 69,345 40,370 28,975 — 11,159,509 40,370 11,069,181 49,958 Real estate loans held for sale 493,453 — 493,453 — Other assets (b) 79,539 — 61,707 17,832 Total assets $ 12,073,211 88,376 11,917,045 67,790 Trading account liabilities $ 233,006 — 233,006 — Other liabilities (b) 9,489 — 9,304 185 Total liabilities $ 242,495 — 242,310 185 Fair value Level 1 (a) Level 2 (a) Level 3 (in thousands) Trading account assets $ 308,175 51,416 256,759 — Investment securities available for sale: U.S. Treasury and federal agencies 161,947 — 161,947 — Obligations of states and political subdivisions 8,198 — 8,198 — Mortgage-backed securities: Government issued or guaranteed 8,731,123 — 8,731,123 — Privately issued 103 — — 103 Collateralized debt obligations 50,316 — — 50,316 Other debt securities 121,488 — 121,488 — Equity securities 83,757 64,841 18,916 — 9,156,932 64,841 9,041,672 50,419 Real estate loans held for sale 742,249 — 742,249 — Other assets (b) 92,129 — 74,733 17,396 Total assets $ 10,299,485 116,257 10,115,413 67,815 Trading account liabilities $ 203,464 — 203,464 — Other liabilities (b) 8,596 — 8,547 49 Total liabilities $ 212,060 — 212,011 49 (a) There were no significant transfers between Level 1 and Level 2 of the fair value hierarchy during the nine months ended September 30, 2015 and the year ended December 31, 2014. (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, 2015 were as follows: Investment securities available for sale Privately issued mortgage-backed Collateralized Other assets (in thousands) Balance – June 30, 2015 $ 88 $ 50,483 $ 11,206 Total gains (losses) realized/unrealized: Included in earnings — — 21,709 (a) Included in other comprehensive income — (472 )(d) — Settlements (6 ) (135 ) — Transfers in and/or out of Level 3 (b) — — (15,268 )(c) 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 (a) The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the three months ended September 30, 2014 were as follows: Investment securities available for sale Privately issued mortgage-backed Collateralized Other assets (in thousands) Balance – June 30, 2014 $ 119 $ 56,200 $ 22,023 Total gains (losses) realized/unrealized: Included in earnings — — 9,657 (a) Included in other comprehensive income — 2,201 (d) — Settlements (7 ) (3,593 ) — Transfers in and/or out of Level 3 (b) — — (15,188 )(c) Balance – September 30, 2014 $ 112 $ 54,808 $ 16,492 Changes in unrealized gains included in earnings related to assets still held at September 30, 2014 $ — $ — $ 12,421 (a) 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 Collateralized Other assets (in thousands) Balance – January 1, 2015 $ 103 $ 50,316 $ 17,347 Total gains (losses) realized/unrealized: Included in earnings — — 67,611 (a) Included in other comprehensive income — 5,153 (d) — Settlements (21 ) (5,593 ) — Transfers in and/or out of Level 3 (b) — — (67,311 )(c) 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 (a) The changes in Level 3 assets and liabilities measured at estimated fair value on a recurring basis during the nine months ended September 30, 2014 were as follows: Investment securities available for sale Privately issued mortgage-backed Collateralized Other assets (in thousands) Balance – January 1, 2014 $ 1,850 $ 63,083 $ 3,941 Total gains (losses) realized/unrealized: Included in earnings — — 63,557 (a) Included in other comprehensive income 272 (d) 11,333 (d) — Settlements (2,010 ) (19,608 ) — Transfers in and/or out of Level 3 (b) — — (51,006 )(c) Balance – September 30, 2014 $ 112 $ 54,808 $ 16,492 Changes in unrealized gains included in earnings related to assets still held at September 30, 2014 $ — $ — $ 17,773 (a) (a) Reported as mortgage banking revenues in the consolidated statement of income and includes the fair value of commitment issuances and expirations. (b) 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. (c) Transfers out of Level 3 consist of interest rate locks transferred to closed loans. (d) Reported as net unrealized gains (losses) on investment securities in the consolidated statement of comprehensive income.
Quantitative Information Related to Significant Unobservable Inputs	The following tables present quantitative information about significant unobservable inputs used in the fair value measurements for Level 3 assets and liabilities at September 30, 2015 and December 31, 2014: Fair value at Valuation Unobservable Range (in thousands) Recurring fair value measurements Privately issued mortgage–backed securities $ 82 Two independent — — Collateralized debt obligations 49,876 Discounted cash flow Probability of default 12%-57% (33%) Loss severity 100% Net other assets (liabilities)(a) 17,647 Discounted cash flow Commitment 0%-66% (38%) Fair value at Valuation Unobservable Range (in thousands) Recurring fair value measurements Privately issued mortgage–backed securities $ 103 Two independent — — Collateralized debt obligations 50,316 Discounted cash flow Probability of default 12%-57% (36%) Loss severity 100% Net other assets (liabilities)(a) 17,347 Discounted cash flow Commitment 0%-96% (17%) (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, 2015 Carrying Estimated Level 1 Level 2 Level 3 (in thousands) Financial assets: Cash and cash equivalents $ 1,249,704 $ 1,249,704 $ 1,193,831 $ 55,873 $ — Interest-bearing deposits at banks 4,713,266 4,713,266 — 4,713,266 — Trading account assets 340,710 340,710 48,006 292,704 — Investment securities 14,494,539 14,521,740 40,370 14,283,075 198,295 Loans and leases: Commercial loans and leases 20,233,177 19,920,031 — — 19,920,031 Commercial real estate loans 28,720,537 28,633,973 — 71,357 28,562,616 Residential real estate loans 8,211,062 8,302,630 — 4,918,613 3,384,017 Consumer loans 11,375,472 11,280,973 — — 11,280,973 Allowance for credit losses (933,798 ) — — — — Loans and leases, net 67,606,450 68,137,607 — 4,989,970 63,147,637 Accrued interest receivable 242,935 242,935 — 242,935 — Financial liabilities: Noninterest-bearing deposits $ (28,189,330 ) $ (28,189,330 ) $ — $ (28,189,330 ) $ — Savings deposits and NOW accounts (41,757,661 ) (41,757,661 ) — (41,757,661 ) — Time deposits (2,791,367 ) (2,810,224 ) — (2,810,224 ) — Deposits at Cayman Islands office (206,185 ) (206,185 ) — (206,185 ) — Short-term borrowings (173,783 ) (173,783 ) — (173,783 ) — Long-term borrowings (10,174,289 ) (10,219,180 ) — (10,219,180 ) — Accrued interest payable (73,475 ) (73,475 ) — (73,475 ) — Trading account liabilities (233,006 ) (233,006 ) — (233,006 ) — Other financial instruments: Commitments to originate real estate loans for sale $ 17,647 $ 17,647 $ — $ — $ 17,647 Commitments to sell real estate loans (8,379 ) (8,379 ) — (8,379 ) — Other credit-related commitments (118,656 ) (118,656 ) — — (118,656 ) Interest rate swap agreements used for interest rate risk management 60,782 60,782 — 60,782 — December 31, 2014 Carrying Estimated Level 1 Level 2 Level 3 (in thousands) Financial assets: Cash and cash equivalents $ 1,373,357 $ 1,373,357 $ 1,296,923 $ 76,434 $ — Interest-bearing deposits at banks 6,470,867 6,470,867 — 6,470,867 — Trading account assets 308,175 308,175 51,416 256,759 — Investment securities 12,993,542 13,023,956 64,841 12,750,396 208,719 Loans and leases: Commercial loans and leases 19,461,292 19,188,574 — — 19,188,574 Commercial real estate loans 27,567,569 27,487,818 — 307,667 27,180,151 Residential real estate loans 8,657,301 8,729,056 — 5,189,086 3,539,970 Consumer loans 10,982,794 10,909,623 — — 10,909,623 Allowance for credit losses (919,562 ) — — — — Loans and leases, net 65,749,394 66,315,071 — 5,496,753 60,818,318 Accrued interest receivable 227,348 227,348 — 227,348 — Financial liabilities: Noninterest-bearing deposits $ (26,947,880 ) $ (26,947,880 ) $ — $ (26,947,880 ) $ — Savings deposits and NOW accounts (43,393,618 ) (43,393,618 ) — (43,393,618 ) — Time deposits (3,063,973 ) (3,086,126 ) — (3,086,126 ) — Deposits at Cayman Islands office (176,582 ) (176,582 ) — (176,582 ) — Short-term borrowings (192,676 ) (192,676 ) — (192,676 ) — Long-term borrowings (9,006,959 ) (9,139,789 ) — (9,139,789 ) — Accrued interest payable (63,372 ) (63,372 ) — (63,372 ) — Trading account liabilities (203,464 ) (203,464 ) — (203,464 ) — Other financial instruments: Commitments to originate real estate loans for sale $ 17,347 $ 17,347 $ — $ — $ 17,347 Commitments to sell real estate loans (7,065 ) (7,065 ) — (7,065 ) — Other credit-related commitments (119,079 ) (119,079 ) — — (119,079 ) Interest rate swap agreements used for interest rate risk management 73,251 73,251 — 73,251 —

Commitments and contingencies (

Commitments and contingencies (Tables)	9 Months Ended
	Sep. 30, 2015
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, 2015 2014 (in thousands) Commitments to extend credit Home equity lines of credit $ 5,535,704 6,194,516 Commercial real estate loans to be sold 89,374 212,257 Other commercial real estate and construction 5,356,256 4,834,699 Residential real estate loans to be sold 587,206 432,352 Other residential real estate 674,338 524,399 Commercial and other 12,144,962 11,080,856 Standby letters of credit 3,441,337 3,706,888 Commercial letters of credit 44,082 46,965 Financial guarantees and indemnification contracts 2,922,743 2,490,050 Commitments to sell real estate loans 977,822 1,237,294

Segment information (Tables)

Segment information (Tables)	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Summary of Prior Period Financial Information Restated	Prior period financial information has been restated to reflect the changes noted to provide segment information on a comparable basis, as noted in the following tables. Three months ended September 30, 2014 Net income (loss) as Impact of Net income (loss) (in thousands) Business Banking $ 30,905 (5,867 ) 25,038 Commercial Banking 101,740 (1,035 ) 100,705 Commercial Real Estate 78,581 95 78,676 Discretionary Portfolio 8,279 4,216 12,495 Residential Mortgage Banking 25,021 (2,272 ) 22,749 Retail Banking 32,901 39,156 72,057 All Other (2,083 ) (34,293 ) (36,376 ) Total $ 275,344 — 275,344 Nine months ended September 30, 2014 Net income (loss) as Impact of Net income (loss) (in thousands) Business Banking $ 87,263 (13,500 ) 73,763 Commercial Banking 306,863 (3,226 ) 303,637 Commercial Real Estate 230,668 (414 ) 230,254 Discretionary Portfolio 34,538 4,360 38,898 Residential Mortgage Banking 72,144 (7,464 ) 64,680 Retail Banking 94,646 119,418 214,064 All Other (37,425 ) (99,174 ) (136,599 ) Total $ 788,697 — 788,697
Information about Company's Segments	Information about the Company’s segments is presented in the following table: Three months ended September 30 2015 2014 Total Inter- Net Total Inter- Net (in thousands) Business Banking $ 112,650 1,167 23,995 $ 113,425 1,082 25,038 Commercial Banking 270,554 1,097 108,422 247,282 1,281 100,705 Commercial Real Estate 181,478 469 85,312 170,772 442 78,676 Discretionary Portfolio 13,773 (5,365 ) 5,113 24,835 (5,478 ) 12,495 Residential Mortgage Banking 99,518 12,918 21,150 104,092 12,875 22,749 Retail Banking 308,520 3,292 64,721 316,052 3,735 72,057 All Other 146,033 (13,578 ) (28,312 ) 143,712 (13,937 ) (36,376 ) Total $ 1,132,526 — 280,401 $ 1,120,170 — 275,344 Nine months ended September 30 2015 2014 Total Inter- Net Total Inter- Net (in thousands) Business Banking $ 332,341 3,334 74,160 337,929 3,359 73,763 Commercial Banking 774,392 3,281 312,926 748,978 3,834 303,637 Commercial Real Estate 535,909 978 250,501 500,814 1,315 230,254 Discretionary Portfolio 49,724 (16,184 ) 21,823 79,404 (15,799 ) 38,898 Residential Mortgage Banking 310,843 36,741 75,462 299,237 34,395 64,680 Retail Banking 914,484 9,688 202,415 934,386 11,137 214,064 All Other 494,779 (37,838 ) (128,585 ) 421,488 (38,241 ) (136,599 ) Total $ 3,412,472 — 808,702 3,322,236 — 788,697
Summary of Segment Information	Average total assets (b) Nine months ended September 30 Year ended December 31 2015 2014 2014 (in millions) Business Banking $ 5,321 5,287 5,281 Commercial Banking 24,041 22,805 22,892 Commercial Real Estate 18,632 17,187 17,370 Discretionary Portfolio 23,153 20,306 20,798 Residential Mortgage Banking 3,007 3,016 3,076 Retail Banking 10,912 10,348 10,449 All Other 12,279 11,003 12,277 Total $ 97,345 89,952 92,143 (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 $6,248,000 and $5,841,000 for the three-month periods ended September 30, 2015 and 2014, respectively, and $18,106,000 and $17,635,000 for the nine-month periods ended September 30, 2015 and 2014, 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. (b) Average assets of the Commercial Real Estate and Residential Mortgage Banking segments for the nine months ended September 30, 2014 and the year ended December 31, 2014 differ by $246 million and $257 million, respectively, from the previously reported balances reflecting the change in the Company’s internal profitability reporting for a builder and developer lending unit which moved assets held by that unit from the Residential Mortgage Banking Segment to the Commercial Real Estate Segment.

Significant Accounting Polici36

Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Significant Accounting Policies [Line Items]
Amount restated as a result of adoption of new guidance	$ 434,710	$ 425,811	$ 1,263,653	$ 1,207,983
Adjustments for New Accounting Pronouncement [Member]
Significant Accounting Policies [Line Items]
Amount restated as a result of adoption of new guidance		$ 14,000		$ 39,000

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Aug. 27, 2012
Business Acquisition [Line Items]
Purchase consideration per common share			$ 0.08403
Percentage of total equity consideration			60.00%
Percentage of total cash consideration			40.00%
Total consideration to be paid	$ 5,300,000
Assets	97,797,062	$ 96,685,535
Loans	67,606,450	65,749,394
Investment securities	14,494,539	12,993,542
Liabilities	84,875,128	84,349,639
Deposits	72,944,543	$ 73,582,053
Hudson City [Member]
Business Acquisition [Line Items]
Assets	35,100,000
Loans	19,200,000
Investment securities	8,300,000
Liabilities	30,300,000
Deposits	$ 17,900,000

Investment Securities - Amortiz

Investment Securities - Amortized Cost and Estimated Fair Value of Investment Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Other securities, Amortized cost	$ 336,544	$ 328,742
Other securities, Gross unrealized gains	0	0
Other securities, Gross unrealized losses	0	0
Other securities, Estimated fair value	336,544	328,742
Investment securities available for sale, amortized cost	10,923,234	8,919,324
Investment securities available for sale, gross unrealized gains	274,610	258,851
Investment securities available for sale, gross unrealized losses	38,335	21,243
Investment securities available for sale, estimated fair value	11,159,509	9,156,932
Amortized cost for held to maturity	2,998,486	3,507,868
Gross unrealized gains for held to maturity	72,509	82,179
Gross unrealized losses for held to maturity	45,308	51,765
Estimated fair value for held to maturity	3,025,687	3,538,282
Total Amortized cost	14,258,264	12,755,934
Total for Gross unrealized gains	347,119	341,030
Total for Gross unrealized losses	83,643	73,008
Total for Estimated fair value	14,521,740	13,023,956
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	6,174	8,027
Investment securities available for sale, gross unrealized gains	170	224
Investment securities available for sale, gross unrealized losses	48	53
Investment securities available for sale, estimated fair value	6,296	8,198
Amortized cost for held to maturity	125,251	148,961
Gross unrealized gains for held to maturity	1,395	2,551
Gross unrealized losses for held to maturity	347	189
Estimated fair value for held to maturity	126,299	151,323
Government Issued or Guaranteed [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	10,504,756	8,507,571
Investment securities available for sale, gross unrealized gains	228,333	223,889
Investment securities available for sale, gross unrealized losses	19,041	337
Investment securities available for sale, estimated fair value	10,714,048	8,731,123
Amortized cost for held to maturity	2,679,546	3,149,320
Gross unrealized gains for held to maturity	69,486	78,485
Gross unrealized losses for held to maturity	4,787	7,000
Estimated fair value for held to maturity	2,744,245	3,220,805
Privately Issued [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	82	104
Investment securities available for sale, gross unrealized gains	2	2
Investment securities available for sale, gross unrealized losses	2	3
Investment securities available for sale, estimated fair value	82	103
Amortized cost for held to maturity	186,883	201,733
Gross unrealized gains for held to maturity	1,628	1,143
Gross unrealized losses for held to maturity	40,174	44,576
Estimated fair value for held to maturity	148,337	158,300
Other Debt Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	136,793	138,240
Investment securities available for sale, gross unrealized gains	1,650	1,896
Investment securities available for sale, gross unrealized losses	17,975	18,648
Investment securities available for sale, estimated fair value	120,468	121,488
Amortized cost for held to maturity	6,806	7,854
Estimated fair value for held to maturity	6,806	7,854
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	197,764	161,408
Investment securities available for sale, gross unrealized gains	1,630	544
Investment securities available for sale, gross unrealized losses		5
Investment securities available for sale, estimated fair value	199,394	161,947
Collateralized Debt Obligations [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	28,467	30,073
Investment securities available for sale, gross unrealized gains	22,465	21,276
Investment securities available for sale, gross unrealized losses	1,056	1,033
Investment securities available for sale, estimated fair value	49,876	50,316
Equity Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Investment securities available for sale, amortized cost	49,198	73,901
Investment securities available for sale, gross unrealized gains	20,360	11,020
Investment securities available for sale, gross unrealized losses	213	1,164
Investment securities available for sale, estimated fair value	$ 69,345	$ 83,757

Investment Securities - Additio

Investment Securities - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2015USD ($)Investment	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)Investment	Sep. 30, 2014USD ($)	Dec. 31, 2014USD ($)
Amortized Cost and Fair Value Debt Securities [Abstract]
Gross realized gain or loss on sale of Investment Securities	$ 0	$ 0	$ 0	$ 0
Number of investment securities with aggregate gross unrealized losses | Investment	320		320
Unrealized losses on individual investment securities	$ 83,643,000		$ 83,643,000		$ 73,008,000
Cost method investment securities	$ 337,000,000		$ 337,000,000

Investment Securities - Amort40

Investment Securities - Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Debt securities available for sale:
Due in one year or less	$ 8,282
Due after one year through five years	197,796
Due after five years through ten years	3,296
Due after ten years	159,824
Total available for sale (amortized cost)	369,198
Mortgage-backed securities available for sale	10,504,838
Total	10,874,036
Debt securities held to maturity:
Due in one year or less	30,523
Due after one year through five years	74,511
Due after five years through ten years	20,217
Due after ten years	6,806
Total available for held to maturity (amortized cost)	132,057
Mortgage-backed securities held to maturity	2,866,429
Amortized cost for held to maturity	2,998,486	$ 3,507,868
Debt securities available for sale:
Due in one year or less	8,330
Due after one year through five years	199,712
Due after five years through ten years	3,495
Due after ten years	164,497
Total available for sale (fair value)	376,034
Mortgage-backed securities available for sale	10,714,130
Total	11,090,164
Debt securities held to maturity:
Due in one year or less	30,706
Due after one year through five years	75,150
Due after five years through ten years	20,443
Due after ten years	6,806
Total available for held to maturity (fair value)	133,105
Mortgage-backed securities held to maturity	2,892,582
Total	$ 3,025,687	$ 3,538,282

Investment Securities - Investm

Investment Securities - Investment Securities in Continuous Unrealized Loss Position (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months	$ 1,967,719	$ 65,554
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Aggregate Losses	(19,709)	(2,659)
Estimated fair value, 12 months or more	96,136	103,914
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(18,626)	(18,584)
Held to maturity, Estimated fair value, Less than 12 months	53,955	167,299
Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses	(421)	(545)
Held to maturity, Estimated fair value, 12 months or more	363,666	574,560
Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses	(44,887)	(51,220)
Total investment securities, fair value less than 12 months	2,021,674	232,853
Investment Securities Continuous Unrealized Loss Position Less Than Twelve Months Aggregate Losses	(20,130)	(3,204)
Total of investment securities, fair value, 12 Months or More	459,802	678,474
Investment Securities Continuous Unrealized Loss Position Twelve Months or Longer Aggregate Losses	(63,513)	(69,804)
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	516	1,785
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Aggregate Losses	(2)	(52)
Estimated fair value, 12 months or more	1,405	121
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(46)	(1)
Held to maturity, Estimated fair value, Less than 12 months	37,336	29,886
Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses	(292)	(184)
Held to maturity, Estimated fair value, 12 months or more	4,096	268
Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses	(55)	(5)
Government Issued or Guaranteed [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months	1,942,135	39,001
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Aggregate Losses	(18,925)	(186)
Estimated fair value, 12 months or more	5,503	5,555
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(116)	(151)
Held to maturity, Estimated fair value, Less than 12 months	16,619	137,413
Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses	(129)	(361)
Held to maturity, Estimated fair value, 12 months or more	240,730	446,780
Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses	(4,658)	(6,639)
Privately Issued [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Held to maturity, Estimated fair value, 12 months or more	118,840	127,512
Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses	(40,174)	(44,576)
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		6,505
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Aggregate Losses		(5)
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	48	65
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(2)	(3)
Collateralized Debt Obligations [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months	5,733	2,108
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Aggregate Losses	(324)	(696)
Estimated fair value, 12 months or more	2,155	5,512
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(732)	(337)
Other Debt Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months	19,335	14,017
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Aggregate Losses	(458)	(556)
Estimated fair value, 12 months or more	86,813	92,661
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	(17,517)	(18,092)
Equity Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Estimated fair value, Less than 12 months		2,138
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Aggregate Losses		$ (1,164)
Estimated fair value, 12 months or more	212
Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or More Aggregate Losses	$ (213)

Loans and Leases and the Allo42

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, 2015	Dec. 31, 2014
Outstanding principal and carrying value of acquired loans recorded at fair value
Outstanding principal balance	$ 2,410,454	$ 3,070,268
Carrying amount	2,029,961	2,596,545
Commercial, Financial, Leasing, etc. [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	103,583	247,820
Commercial Real Estate [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	728,376	961,828
Residential Real Estate [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	385,885	453,360
Consumer [Member]
Outstanding principal and carrying value of acquired loans recorded at fair value
Carrying amount	$ 812,117	$ 933,537

Loans and Leases and the Allo43

Loans and Leases and the Allowance for Credit Losses - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contractual principal and interest payments	$ 149	$ 198
Purchased impaired loans as a percentage of total assets	Less than 1%
Commercial mortgage loans held for sale	$ 71	308
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	$ 43	44
Loans secured by residential real estate that were in the process of foreclosure	151
Residential Mortgage Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans held for sale	422	435
Carrying value of loans for which partial charge-off has been recognized	59	63
Mortgage loans, customer balance outstanding	20	27
Home Equity Loans and Lines of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value of loans for which partial charge-off has been recognized	20	18
Mortgage loans, customer balance outstanding	$ 28	$ 28

Loans and Leases and the Allo44

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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Purchased Impaired [Member]
Summary of changes in Accretable Yield for acquired loans
Balance at beginning of period	$ 77,624	$ 26,082	$ 76,518	$ 37,230
Interest income	(5,865)	(4,149)	(16,843)	(15,583)
Reclassifications from nonaccretable balance	47	129	12,131	415
Balance at end of period	71,806	22,062	71,806	22,062
Other Acquired [Member]
Summary of changes in Accretable Yield for acquired loans
Balance at beginning of period	344,989	450,970	397,379	538,633
Interest income	(37,396)	(39,019)	(118,697)	(135,105)
Reclassifications from nonaccretable balance	769	9,673	27,792	10,448
Other	4,697	1,870	6,585	9,518
Balance at end of period	$ 313,059	$ 423,494	$ 313,059	$ 423,494

Loans and Leases and the Allo45

Loans and Leases and the Allowance for Credit Losses - Summary of Current, Past Due and Nonaccrual Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	$ 66,788,173	$ 64,785,780
30-89 Days past due	503,264	530,901
Purchased impaired	149,421	197,737
Nonaccrual	787,098	799,151
Loans and leases, net of unearned discount	68,540,248	66,668,956
Commercial, Financial, Leasing, etc. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	19,965,307	19,228,265
30-89 Days past due	29,451	37,246
Purchased impaired	4,645	10,300
Nonaccrual	224,415	177,445
Loans and leases, net of unearned discount	20,233,177	19,461,292
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	23,184,906	22,208,491
30-89 Days past due	105,140	118,704
Purchased impaired	45,523	51,312
Nonaccrual	176,491	141,600
Loans and leases, net of unearned discount	23,551,595	22,556,939
Residential Builder and Developer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,479,659	1,273,607
30-89 Days past due	15,951	11,827
Purchased impaired	65,102	98,347
Nonaccrual	46,022	71,517
Loans and leases, net of unearned discount	1,614,222	1,465,140
Other Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	3,493,349	3,484,932
30-89 Days past due	28,433	17,678
Purchased impaired	17,484	17,181
Nonaccrual	12,312	25,699
Loans and leases, net of unearned discount	3,554,720	3,545,490
Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	7,323,813	7,640,368
30-89 Days past due	206,044	226,932
Purchased impaired	14,392	18,223
Nonaccrual	153,354	180,275
Loans and leases, net of unearned discount	7,908,178	8,318,013
Residential Alt-A [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	226,871	249,810
30-89 Days past due	11,662	11,774
Nonaccrual	64,351	77,704
Loans and leases, net of unearned discount	302,884	339,288
Home Equity Lines and Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	5,710,632	5,859,378
30-89 Days past due	38,506	42,945
Purchased impaired	2,275	2,374
Nonaccrual	78,126	89,291
Loans and leases, net of unearned discount	5,844,993	6,021,884
Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	2,319,556	1,931,138
30-89 Days past due	36,867	30,500
Nonaccrual	13,892	17,578
Loans and leases, net of unearned discount	2,370,368	1,979,349
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	3,084,080	2,909,791
30-89 Days past due	31,210	33,295
Nonaccrual	18,135	18,042
Loans and leases, net of unearned discount	3,160,111	2,981,561
Non-Acquired [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
90 Days or more past due and accruing	231,465	245,020
Non-Acquired [Member] | Commercial, Financial, Leasing, etc. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
90 Days or more past due and accruing	5,882	1,805
Non-Acquired [Member] | Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
90 Days or more past due and accruing	21,629	22,170
Non-Acquired [Member] | Residential Builder and Developer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
90 Days or more past due and accruing		492
Non-Acquired [Member] | Other Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
90 Days or more past due and accruing	1,373
Non-Acquired [Member] | Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
90 Days or more past due and accruing	194,280	216,489
Non-Acquired [Member] | Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
90 Days or more past due and accruing	8,301	4,064
Acquired [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
90 Days or more past due and accruing	80,827	110,367
Acquired [Member] | Commercial, Financial, Leasing, etc. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
90 Days or more past due and accruing	3,477	6,231
Acquired [Member] | Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
90 Days or more past due and accruing	17,906	14,662
Acquired [Member] | Residential Builder and Developer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
90 Days or more past due and accruing	7,488	9,350
Acquired [Member] | Other Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
90 Days or more past due and accruing	1,769
Acquired [Member] | Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
90 Days or more past due and accruing	16,295	35,726
Acquired [Member] | Home Equity Lines and Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
90 Days or more past due and accruing	15,454	27,896
Acquired [Member] | Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
90 Days or more past due and accruing	53	133
Acquired [Member] | Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
90 Days or more past due and accruing	$ 18,385	$ 16,369

Loans and Leases and the Allo46

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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$ 929,987	$ 917,666	$ 919,562	$ 916,676
Provision for credit losses	44,000	29,000	112,000	91,000
Net charge-offs
Charge-offs	(53,141)	(43,092)	(133,579)	(132,369)
Recoveries	12,952	15,059	35,815	43,326
Net charge-offs	(40,189)	(28,033)	(97,764)	(89,043)
Ending balance	933,798	918,633	933,798	918,633
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	286,750	292,251	288,038	273,383
Provision for credit losses	21,507	2,373	32,686	40,527
Net charge-offs
Charge-offs	(26,912)	(15,921)	(46,990)	(44,872)
Recoveries	5,322	7,849	12,933	17,514
Net charge-offs	(21,590)	(8,072)	(34,057)	(27,358)
Ending balance	286,667	286,552	286,667	286,552
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	311,294	311,254	307,927	324,978
Provision for credit losses	1,879	8,046	13,769	(4,067)
Net charge-offs
Charge-offs	(2,203)	(1,666)	(12,352)	(7,966)
Recoveries	2,119	1,267	3,745	5,956
Net charge-offs	(84)	(399)	(8,607)	(2,010)
Ending balance	313,089	318,901	313,089	318,901
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	60,294	72,404	61,910	78,656
Provision for credit losses	(3,155)	(3,187)	(571)	(916)
Net charge-offs
Charge-offs	(3,268)	(4,193)	(9,695)	(17,124)
Recoveries	1,125	2,498	3,352	6,906
Net charge-offs	(2,143)	(1,695)	(6,343)	(10,218)
Ending balance	54,996	67,522	54,996	67,522
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	194,238	165,871	186,033	164,644
Provision for credit losses	24,448	21,815	65,038	54,632
Net charge-offs
Charge-offs	(20,758)	(21,312)	(64,542)	(62,407)
Recoveries	4,386	3,445	15,785	12,950
Net charge-offs	(16,372)	(17,867)	(48,757)	(49,457)
Ending balance	202,314	169,819	202,314	169,819
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	77,411	75,886	75,654	75,015
Provision for credit losses	(679)	(47)	1,078	824
Net charge-offs
Ending balance	$ 76,732	$ 75,839	$ 76,732	$ 75,839

Loans and Leases and the Allo47

Loans and Leases and the Allowance for Credit Losses - Impaired Loans and Leases (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule Of Financial Receivables [Line Items]
Recorded investment with related allowance	$ 501,230	$ 498,575
Unpaid principal balance with related allowance	579,049	581,887
Related allowance	82,726	82,643
Recorded investment with no related allowance	278,400	263,880
Unpaid principal balance with no related allowance	377,625	371,907
Recorded investment	779,630	762,455
Unpaid principal balance	956,674	953,794
Related allowance	82,726	82,643
Commercial, Financial, Leasing, etc. [Member]
Schedule Of Financial Receivables [Line Items]
Recorded investment with related allowance	144,051	132,340
Unpaid principal balance with related allowance	166,877	165,146
Related allowance	35,195	31,779
Recorded investment with no related allowance	111,023	73,978
Unpaid principal balance with no related allowance	133,100	81,493
Recorded investment	255,074	206,318
Unpaid principal balance	299,977	246,639
Related allowance	35,195	31,779
Commercial Real Estate [Member]
Schedule Of Financial Receivables [Line Items]
Recorded investment with related allowance	105,561	83,955
Unpaid principal balance with related allowance	122,369	96,209
Related allowance	18,932	14,121
Recorded investment with no related allowance	77,147	66,777
Unpaid principal balance with no related allowance	84,677	78,943
Recorded investment	182,708	150,732
Unpaid principal balance	207,046	175,152
Related allowance	18,932	14,121
Residential Builder and Developer [Member]
Schedule Of Financial Receivables [Line Items]
Recorded investment with related allowance	6,544	17,632
Unpaid principal balance with related allowance	10,276	22,044
Related allowance	788	805
Recorded investment with no related allowance	42,800	58,820
Unpaid principal balance with no related allowance	68,906	96,722
Recorded investment	49,344	76,452
Unpaid principal balance	79,182	118,766
Related allowance	788	805
Other Commercial Construction [Member]
Schedule Of Financial Receivables [Line Items]
Recorded investment with related allowance	2,445	5,480
Unpaid principal balance with related allowance	3,991	6,484
Related allowance	391	900
Recorded investment with no related allowance	10,307	20,738
Unpaid principal balance with no related allowance	28,480	41,035
Recorded investment	12,752	26,218
Unpaid principal balance	32,471	47,519
Related allowance	391	900
Residential [Member]
Schedule Of Financial Receivables [Line Items]
Recorded investment with related allowance	83,349	88,970
Unpaid principal balance with related allowance	101,367	107,343
Related allowance	4,775	4,296
Recorded investment with no related allowance	16,232	16,815
Unpaid principal balance with no related allowance	26,626	26,750
Recorded investment	99,581	105,785
Unpaid principal balance	127,993	134,093
Related allowance	4,775	4,296
Residential Alt-A [Member]
Schedule Of Financial Receivables [Line Items]
Recorded investment with related allowance	93,168	101,137
Unpaid principal balance with related allowance	107,075	114,565
Related allowance	8,500	11,000
Recorded investment with no related allowance	20,891	26,752
Unpaid principal balance with no related allowance	35,836	46,964
Recorded investment	114,059	127,889
Unpaid principal balance	142,911	161,529
Related allowance	8,500	11,000
Home Equity Lines and Loans [Member]
Schedule Of Financial Receivables [Line Items]
Recorded investment with related allowance	23,257	19,771
Unpaid principal balance with related allowance	24,239	20,806
Related allowance	3,541	6,213
Recorded investment	23,257	19,771
Unpaid principal balance	24,239	20,806
Related allowance	3,541	6,213
Automobile [Member]
Schedule Of Financial Receivables [Line Items]
Recorded investment with related allowance	23,985	30,317
Unpaid principal balance with related allowance	23,985	30,317
Related allowance	5,118	8,070
Recorded investment	23,985	30,317
Unpaid principal balance	23,985	30,317
Related allowance	5,118	8,070
Other [Member]
Schedule Of Financial Receivables [Line Items]
Recorded investment with related allowance	18,870	18,973
Unpaid principal balance with related allowance	18,870	18,973
Related allowance	5,486	5,459
Recorded investment	18,870	18,973
Unpaid principal balance	18,870	18,973
Related allowance	$ 5,486	$ 5,459

Loans and Leases and the Allo48

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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	$ 773,478	$ 875,395	$ 763,272	$ 875,219
Interest income recognized, Total	9,552	5,596	20,895	21,405
Interest income recognized, Cash basis	7,430	3,350	14,371	14,421
Commercial, Financial, Leasing, etc. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	242,157	228,749	226,243	171,227
Interest income recognized, Total	1,017	611	2,123	1,379
Interest income recognized, Cash basis	1,017	611	2,123	1,379
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	179,327	189,952	161,834	194,337
Interest income recognized, Total	2,327	821	4,433	2,616
Interest income recognized, Cash basis	2,327	821	4,433	2,616
Residential Builder and Developer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	53,009	90,493	64,165	94,453
Interest income recognized, Total	81	18	275	131
Interest income recognized, Cash basis	81	18	275	131
Other Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	17,236	58,500	22,130	74,531
Interest income recognized, Total	1,943	251	2,166	1,694
Interest income recognized, Cash basis	1,943	251	2,166	1,694
Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	99,939	104,516	101,997	132,606
Interest income recognized, Total	1,835	1,328	4,639	7,784
Interest income recognized, Cash basis	1,316	776	3,011	6,146
Residential Alt-A [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	116,191	131,574	120,710	135,374
Interest income recognized, Total	1,539	1,643	4,799	5,002
Interest income recognized, Cash basis	618	681	1,962	1,900
Home Equity Lines and Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	21,952	19,268	20,619	17,902
Interest income recognized, Total	231	219	656	540
Interest income recognized, Cash basis	66	81	179	182
Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	24,429	33,666	26,521	36,560
Interest income recognized, Total	391	528	1,257	1,742
Interest income recognized, Cash basis	39	67	136	228
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	19,238	18,677	19,053	18,229
Interest income recognized, Total	188	177	547	517
Interest income recognized, Cash basis	$ 23	$ 44	$ 86	$ 145

Loans and Leases and the Allo49

Loans and Leases and the Allowance for Credit Losses - Summary of Loan Grades (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	$ 68,540,248	$ 66,668,956
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	20,233,177	19,461,292
Commercial, Financial, Leasing, etc. [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	19,223,102	18,695,440
Commercial, Financial, Leasing, etc. [Member] | Criticized Accrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	785,660	588,407
Commercial, Financial, Leasing, etc. [Member] | Criticized Nonaccrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	224,415	177,445
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	23,551,595	22,556,939
Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	22,479,501	21,837,022
Commercial [Member] | Criticized Accrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	895,603	578,317
Commercial [Member] | Criticized Nonaccrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	176,491	141,600
Residential Builder and Developer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	1,614,222	1,465,140
Residential Builder and Developer [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	1,507,057	1,347,778
Residential Builder and Developer [Member] | Criticized Accrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	61,143	45,845
Residential Builder and Developer [Member] | Criticized Nonaccrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	46,022	71,517
Other Commercial Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	3,554,720	3,545,490
Other Commercial Construction [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	3,447,841	3,347,522
Other Commercial Construction [Member] | Criticized Accrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	94,567	172,269
Other Commercial Construction [Member] | Criticized Nonaccrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	$ 12,312	$ 25,699

Loans and Leases and the Allo50

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, 2015	Jun. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	$ 82,358		$ 81,714
Allowance for credit losses	768,995		753,052
Allowance for credit losses	933,798	$ 929,987	919,562	$ 918,633	$ 917,666	$ 916,676
Purchased Impaired [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	5,713		9,142
Allocated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	857,066		843,908
Unallocated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	76,732	$ 77,411	75,654	$ 75,839	$ 75,886	$ 75,015
Commercial, Financial, Leasing, etc. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	35,195		31,779
Allowance for credit losses	250,271		251,607
Commercial, Financial, Leasing, etc. [Member] | Purchased Impaired [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	1,201		4,652
Commercial, Financial, Leasing, etc. [Member] | Allocated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	286,667		288,038
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	19,743		15,490
Allowance for credit losses	292,214		291,244
Commercial Real Estate [Member] | Purchased Impaired [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	1,132		1,193
Commercial Real Estate [Member] | Allocated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	313,089		307,927
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	13,275		14,703
Allowance for credit losses	39,804		45,061
Residential Real Estate [Member] | Purchased Impaired [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	1,917		2,146
Residential Real Estate [Member] | Allocated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	54,996		61,910
Consumer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	14,145		19,742
Allowance for credit losses	186,706		165,140
Consumer Loans [Member] | Purchased Impaired [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	1,463		1,151
Consumer Loans [Member] | Allocated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	$ 202,314		$ 186,033

Loans and Leases and the Allo51

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, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	$ 68,540,248	$ 66,668,956
Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	778,569	760,124
Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	67,612,258	65,711,095
Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	149,421	197,737
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	20,233,177	19,461,292
Commercial, Financial, Leasing, etc. [Member] | Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	255,074	206,318
Commercial, Financial, Leasing, etc. [Member] | Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	19,973,458	19,244,674
Commercial, Financial, Leasing, etc. [Member] | Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	4,645	10,300
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	28,720,537	27,567,569
Commercial Real Estate [Member] | Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	243,743	252,347
Commercial Real Estate [Member] | Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	28,348,685	27,148,382
Commercial Real Estate [Member] | Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	128,109	166,840
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	8,211,062	8,657,301
Residential Real Estate [Member] | Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	213,640	232,398
Residential Real Estate [Member] | Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	7,983,030	8,406,680
Residential Real Estate [Member] | Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	14,392	18,223
Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	11,375,472	10,982,794
Consumer Loans [Member] | Individually Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	66,112	69,061
Consumer Loans [Member] | Collectively Evaluated for Impairment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	11,307,085	10,911,359
Consumer Loans [Member] | Purchased Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases, net of unearned discount	$ 2,275	$ 2,374

Loans and Leases and the Allo52

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, 2015USD ($)Modification	Sep. 30, 2014USD ($)Modification	Sep. 30, 2015USD ($)Modification	Sep. 30, 2014USD ($)Modification
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	245	154	613	590
Pre-modification, Recorded Investment	$ 23,691	$ 9,009	$ 139,888	$ 98,923
Post-modification, Recorded investment	23,657	8,388	137,646	98,185
Financial effects of modification, Recorded investment	(34)	(621)	(2,242)	(738)
Financial Effects of Modification, Interest	$ (557)	$ (505)	$ (1,406)	$ (2,385)
Principal Deferral [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	36	15	87	66
Pre-modification, Recorded Investment	$ 7,893	$ 1,305	$ 25,483	$ 20,673
Post-modification, Recorded investment	7,419	1,300	24,331	20,499
Financial effects of modification, Recorded investment	$ (474)	$ (5)	$ (1,152)	$ (174)
Principal Deferral [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	15	8	37	32
Pre-modification, Recorded Investment	$ 4,230	$ 2,081	$ 47,005	$ 17,452
Post-modification, Recorded investment	4,208	2,068	45,569	17,384
Financial effects of modification, Recorded investment	$ (22)	$ (13)	$ (1,436)	$ (68)
Principal Deferral [Member] | Residential Builder and Developer [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification		1	2	2
Pre-modification, Recorded Investment		$ 241	$ 10,650	$ 1,639
Post-modification, Recorded investment		$ 241	10,598	$ 1,639
Financial effects of modification, Recorded investment			$ (52)
Principal Deferral [Member] | Other Commercial Construction [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	3	1	3	4
Pre-modification, Recorded Investment	$ 296	$ 145	$ 296	$ 6,703
Post-modification, Recorded investment	390	142	390	6,611
Financial effects of modification, Recorded investment	$ 94	$ (3)	$ 94	$ (92)
Principal Deferral [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	31	3	50	19
Pre-modification, Recorded Investment	$ 3,540	$ 98	$ 4,954	$ 1,842
Post-modification, Recorded investment	3,743	97	5,239	1,926
Financial effects of modification, Recorded investment	$ 203	$ (1)	$ 285	$ 84
Principal Deferral [Member] | Residential Alt-A [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	1		2	5
Pre-modification, Recorded Investment	$ 265		$ 426	$ 828
Post-modification, Recorded investment	276		437	900
Financial effects of modification, Recorded investment	$ 11		$ 11	$ 72
Principal Deferral [Member] | Home Equity Lines and Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	4		6	3
Pre-modification, Recorded Investment	$ 727		$ 1,946	$ 280
Post-modification, Recorded investment	$ 727		$ 1,946	$ 280
Principal Deferral [Member] | Automobile [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	35	45	133	168
Pre-modification, Recorded Investment	$ 316	$ 1,003	$ 1,234	$ 2,599
Post-modification, Recorded investment	$ 316	$ 1,003	$ 1,234	$ 2,599
Principal Deferral [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	24	6	73	21
Pre-modification, Recorded Investment	$ 352	$ 48	$ 1,418	$ 141
Post-modification, Recorded investment	$ 352	$ 48	$ 1,418	$ 141
Other [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification			2	1
Pre-modification, Recorded Investment			$ 8,991	$ 19,593
Post-modification, Recorded investment			8,883	$ 19,593
Financial effects of modification, Recorded investment			$ (108)
Other [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification		1		1
Pre-modification, Recorded Investment		$ 650		$ 650
Financial effects of modification, Recorded investment		$ (650)		$ (650)
Other [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	1		1	1
Pre-modification, Recorded Investment	$ 267		$ 267	$ 188
Post-modification, Recorded investment	$ 267		$ 267	$ 188
Other [Member] | Automobile [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	15	7	38	26
Pre-modification, Recorded Investment	$ 93	$ 96	$ 134	$ 204
Post-modification, Recorded investment	$ 93	$ 96	$ 134	$ 204
Other [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	5		12	1
Pre-modification, Recorded Investment	$ 33		$ 113	$ 45
Post-modification, Recorded investment	$ 33		$ 113	$ 45
Combination of Concession Types [Member] | Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	1		6	5
Pre-modification, Recorded Investment	$ 31		$ 25,075	$ 9,836
Post-modification, Recorded investment	31		24,884	9,766
Financial effects of modification, Recorded investment			(191)	(70)
Financial Effects of Modification, Interest	$ (6)		$ (245)	$ (14)
Combination of Concession Types [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	1	4	6	6
Pre-modification, Recorded Investment	$ 1,156	$ 483	$ 3,238	$ 892
Post-modification, Recorded investment	1,169	478	3,242	940
Financial effects of modification, Recorded investment	13	(5)	4	48
Financial Effects of Modification, Interest	$ (54)	$ (95)	$ (159)	$ (208)
Combination of Concession Types [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	10	8	22	30
Pre-modification, Recorded Investment	$ 1,296	$ 1,100	$ 2,551	$ 4,211
Post-modification, Recorded investment	1,380	1,136	2,795	4,287
Financial effects of modification, Recorded investment	84	36	244	76
Financial Effects of Modification, Interest	$ (178)	$ (135)	$ (356)	$ (483)
Combination of Concession Types [Member] | Residential Alt-A [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	4	3	7	19
Pre-modification, Recorded Investment	$ 605	$ 349	$ 1,239	$ 3,101
Post-modification, Recorded investment	662	369	1,298	3,134
Financial effects of modification, Recorded investment	57	20	59	33
Financial Effects of Modification, Interest	$ (91)	$ (64)	$ (121)	$ (345)
Combination of Concession Types [Member] | Home Equity Lines and Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	22	5	41	41
Pre-modification, Recorded Investment	$ 2,003	$ 519	$ 3,555	$ 4,147
Post-modification, Recorded investment	2,003	519	3,555	4,147
Financial Effects of Modification, Interest	$ (199)	$ (67)	$ (424)	$ (443)
Combination of Concession Types [Member] | Automobile [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	25	19	42	65
Pre-modification, Recorded Investment	$ 471	$ 348	$ 693	$ 939
Post-modification, Recorded investment	471	348	693	939
Financial Effects of Modification, Interest	$ (17)	$ (21)	$ (28)	$ (83)
Combination of Concession Types [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	12	24	35	57
Pre-modification, Recorded Investment	$ 117	$ 511	$ 384	$ 1,883
Post-modification, Recorded investment	117	511	384	1,883
Financial Effects of Modification, Interest	$ (12)	$ (121)	$ (44)	$ (585)
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] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification				1
Pre-modification, Recorded Investment				$ 255
Post-modification, Recorded investment				252
Financial effects of modification, Recorded investment				(3)
Financial Effects of Modification, Interest				$ (48)
Interest Rate Reduction [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification				1
Pre-modification, Recorded Investment				$ 98
Post-modification, Recorded investment				104
Financial effects of modification, Recorded investment				6
Financial Effects of Modification, Interest				$ (32)
Interest Rate Reduction [Member] | Home Equity Lines and Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification				5
Pre-modification, Recorded Investment				$ 341
Post-modification, Recorded investment				341
Financial Effects of Modification, Interest				$ (76)
Interest Rate Reduction [Member] | Automobile [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification		3	7	6
Pre-modification, Recorded Investment		$ 30	$ 137	$ 90
Post-modification, Recorded investment		30	137	90
Financial Effects of Modification, Interest		$ (2)	$ (10)	$ (5)
Interest Rate Reduction [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification		1		4
Pre-modification, Recorded Investment		$ 2		$ 293
Post-modification, Recorded investment		$ 2		293
Financial Effects of Modification, Interest				$ (63)

Borrowings - Additional Informa

Borrowings - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Feb. 28, 2015	Dec. 31, 2014	Feb. 27, 2014
Schedule Of Borrowings [Line Items]
Interest rate of debt instrument				8.50%
Junior subordinated debentures	$ 513
Agreements to repurchase securities	1,400		$ 1,400
Collateral posted	$ 1,500		$ 1,500
Senior Notes Due 2020 [Member]
Schedule Of Borrowings [Line Items]
Interest rate of debt instrument		2.10%
Fixed rate senior notes issued		$ 750
Senior Notes Due 2025 [Member]
Schedule Of Borrowings [Line Items]
Interest rate of debt instrument		2.90%
Fixed rate senior notes issued		$ 750
Senior Notes [Member]
Schedule Of Borrowings [Line Items]
Fixed rate senior notes issued		$ 1,500
Junior Subordinated Debt [Member]
Schedule Of Borrowings [Line Items]
Debt Maturity, Start Year	Jan. 1, 2027
Debt Maturity, End Year	Dec. 31, 2033
Junior subordinated debentures redeemed	$ 323
Trust Preferred Securities Subject to Mandatory Redemption [Member]
Schedule Of Borrowings [Line Items]
Junior subordinated debentures				$ 350

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail) - $ / shares	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Class of Stock [Line Items]
Preferred stock, shares authorized	1,000,000	1,000,000	1,000,000
Preferred stock, par value	$ 1	$ 1	$ 1
Warrant [Member] | Series D Fixed Rate Non-Cumulative Perpetual Preferred Stock [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, 2015	Dec. 31, 2014
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 - Issued56

Shareholders' Equity - Issued and Outstanding Preferred Stock (Parenthetical) (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
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	719,175	721,490
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 Stock, Redemption Feature, Redemption Term	90 days
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 Stock, Redemption Feature, Redemption Term	90 days
Preferred shares redemption date	Feb. 15, 2024
Date of change in the dividend rate	Feb. 14, 2024
London Interbank offered rate plus basis points	3.61%

Pension Plans and Other Postr57

Pension Plans and Other Postretirement Benefits - Net Periodic Benefit Cost for Defined Benefit Plans (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 5,916	$ 5,130	$ 17,748	$ 15,390
Interest cost on projected benefit obligation	17,754	17,290	53,261	51,871
Expected return on plan assets	(23,527)	(22,892)	(70,578)	(68,676)
Amortization of prior service credit	(1,501)	(1,638)	(4,504)	(4,914)
Amortization of net actuarial loss	11,207	3,624	33,619	10,871
Net periodic benefit cost	9,849	1,514	29,546	4,542
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	188	151	562	453
Interest cost on projected benefit obligation	651	695	1,953	2,084
Amortization of prior service credit	(340)	(340)	(1,019)	(1,019)
Amortization of net actuarial loss	26		79
Net periodic benefit cost	$ 525	$ 506	$ 1,575	$ 1,518

Pension Plans and Other Postr58

Pension Plans and Other Postretirement Benefits - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Compensation and Retirement Disclosure [Abstract]
Defined contribution pension and retirement savings plans total expense	$ 14,281,000	$ 13,558,000	$ 44,377,000	$ 41,963,000

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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income available to common shareholders:
Net income	$ 280,401	$ 275,344	$ 808,702	$ 788,697
Less: Preferred stock dividends	(20,318)	(20,443)	(60,953)	(55,560)
Net income available to common equity	260,083	254,901	747,749	733,137
Less: Income attributable to unvested stock-based compensation awards	(2,746)	(2,996)	(8,122)	(8,830)
Net income available to common shareholders	$ 257,337	$ 251,905	$ 739,627	$ 724,307
Weighted-average shares outstanding:
Common shares outstanding (including common stock issuable) and unvested stock-based compensation awards	134,049	132,832	133,805	132,372
Less: Unvested stock-based compensation awards	(1,419)	(1,567)	(1,458)	(1,590)
Weighted-average shares outstanding	132,630	131,265	132,347	130,782
Basic earnings per common share	$ 1.94	$ 1.92	$ 5.59	$ 5.54

Earnings Per Common Share - C60

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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Net income available to common equity	$ 260,083	$ 254,901	$ 747,749	$ 733,137
Less: Income attributable to unvested stock-based compensation awards	(2,737)	(2,984)	(8,093)	(8,793)
Net income available to common shareholders	$ 257,346	$ 251,917	$ 739,656	$ 724,344
Adjusted weighted-average shares outstanding:
Common and unvested stock-based compensation awards	134,049	132,832	133,805	132,372
Less: Unvested stock-based compensation awards	(1,419)	(1,567)	(1,458)	(1,590)
Plus: Incremental shares from assumed conversion of stock-based compensation awards and warrants to purchase common stock	746	863	742	916
Adjusted weighted-average shares outstanding	133,376	132,128	133,089	131,698
Diluted earnings per common share	$ 1.93	$ 1.91	$ 5.56	$ 5.50

Earnings Per Common Share - Add

Earnings Per Common Share - Additional Information (Detail) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Antidilutive securities excluded from computation of earnings per share	1.5	1.7	1.9	2.1

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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			$ (297,843)	$ (105,797)
Unrealized holding gains (losses), net			(1,440)	121,301
Foreign currency translation adjustment			(735)	(2,314)
Unrealized Gains (losses) on cash flow hedges			1,453	(162)
Total other comprehensive income before reclassifications			(722)	118,825
Accretion of unrealized holding losses on held-to-maturity ("HTM") securities			2,417	2,540
Losses realized in net income			108
Accretion of net gain on terminated cash flow hedges			(102)
Amortization of prior service credit			(5,523)	(5,933)
Amortization of actuarial losses			33,698	10,871
Total reclassifications			30,598	7,478
Total gain (loss) during the period			29,876	126,303
Ending balance	$ (267,967)	$ 20,506	(267,967)	20,506
Beginning balance			116,849	41,638
Unrealized holding gains (losses), net			952	(47,615)
Foreign currency translation adjustment			214	810
Unrealized Gains (losses) on cash flow hedges			(568)	64
Total other comprehensive income before reclassifications			598	(46,741)
Accretion of unrealized holding losses on held-to-maturity ("HTM") securities			(944)	(997)
Losses realized in net income			(40)
Accretion of net gain on terminated cash flow hedges			40
Amortization of prior service credit			2,359	2,328
Amortization of actuarial losses			(14,368)	(4,267)
Total reclassifications			(12,953)	(2,936)
Total gain (loss) during the period			(12,355)	(49,677)
Ending balance	104,494	(8,039)	104,494	(8,039)
Beginning balance			(180,994)	(64,159)
Unrealized holding gains (losses), net			(488)	73,686
Foreign currency translation adjustment	(3)	(1,817)	(521)	(1,504)
Unrealized Gains (losses) on cash flow hedges			885	(98)
Total other comprehensive income before reclassifications			(124)	72,084
Accretion of unrealized holding losses on held-to-maturity ("HTM") securities			1,473	1,543
Losses realized in net income			68
Accretion of net gain on terminated cash flow hedges			(62)
Amortization of prior service credit			(3,164)	(3,605)
Amortization of actuarial losses			19,330	6,604
Total reclassifications			17,645	4,542
Total gain (loss) during the period			17,521	76,626
Ending balance	(163,473)	12,467	(163,473)	12,467
Investment Securities With OTTI [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			7,438	37,255
Unrealized holding gains (losses), net			9,699	12,038
Total other comprehensive income before reclassifications			9,699	12,038
Accretion of unrealized holding losses on held-to-maturity ("HTM") securities				1
Total reclassifications				1
Total gain (loss) during the period			9,699	12,039
Ending balance	17,137	49,294	17,137	49,294
Investment Securities All Other [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			201,828	18,450
Unrealized holding gains (losses), net			(11,139)	109,263
Total other comprehensive income before reclassifications			(11,139)	109,263
Accretion of unrealized holding losses on held-to-maturity ("HTM") securities			2,417	2,539
Losses realized in net income			108
Total reclassifications			2,525	2,539
Total gain (loss) during the period			(8,614)	111,802
Ending balance	193,214	130,252	193,214	130,252
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(503,027)	(161,617)
Amortization of prior service credit			(5,523)	(5,933)
Amortization of actuarial losses			33,698	10,871
Total reclassifications			28,175	4,938
Total gain (loss) during the period			28,175	4,938
Ending balance	(474,852)	(156,679)	(474,852)	(156,679)
Beginning balance			(305,589)
Total gain (loss) during the period			16,166
Ending balance	(289,423)		(289,423)
Other [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(4,082)	115
Foreign currency translation adjustment			(735)	(2,314)
Unrealized Gains (losses) on cash flow hedges			1,453	(162)
Total other comprehensive income before reclassifications			718	(2,476)
Accretion of net gain on terminated cash flow hedges			(102)
Total reclassifications			(102)
Total gain (loss) during the period			616	(2,476)
Ending balance	$ (3,466)	$ (2,361)	$ (3,466)	$ (2,361)

Comprehensive Income - Accumula

Comprehensive Income - Accumulated Other Comprehensive Income (Loss), Net (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (180,994)	$ (64,159)
Net gain (loss) during period	17,521	76,626
Ending balance	(163,473)	$ 12,467
Investment Securities With OTTI [Member] | Investment Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	4,518
Net gain (loss) during period	5,926
Ending balance	10,444
Investment Securities All Other [Member] | Investment Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	122,683
Net gain (loss) during period	(4,873)
Ending balance	117,810
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(305,589)
Net gain (loss) during period	16,166
Ending balance	(289,423)
Accumulated Other Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(2,606)
Net gain (loss) during period	302
Ending balance	$ (2,304)

Derivative Financial Instrume64

Derivative Financial Instruments - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Derivative [Line Items]
Net unrealized pre-tax gains related to hedged loans held for sale, commitments to originate loans for sale and commitments to sell loans	$ 23,000,000		$ 23,000,000		$ 28,000,000
Aggregate fair value of derivative financial instruments in a liability position	96,000,000		96,000,000		161,000,000
Net liability positions with counterparties	91,000,000		91,000,000		103,000,000
Post collateral requirements relating to positions	81,000,000		81,000,000		90,000,000
Aggregate fair value of derivative financial instruments in asset position	40,000,000		40,000,000		104,000,000
Net asset positions with counterparties	35,000,000		35,000,000		46,000,000
Counterparties posted collateral relating to positions	35,000,000		35,000,000		46,000,000
Clearinghouse Credit Facilities [Member]
Derivative [Line Items]
Post collateral requirements relating to positions	143,000,000		143,000,000		61,000,000
Aggregate fair value of derivative financial instruments in a net liability position	96,000,000		96,000,000		35,000,000
Credit Risk Derivative [Member]
Derivative [Line Items]
Aggregate fair value of derivative financial instruments in a net liability position	17,000,000		17,000,000
Fair value of collateral already posted for derivative financial instruments	11,000,000		11,000,000
Fair value of additional collateral to be posted for derivative financial instruments	6,000,000		6,000,000
Interest Rate Swap Agreements [Member]
Derivative [Line Items]
Increase in net interest income due to interest rate swap agreements	11,000,000	$ 11,000,000	33,000,000	$ 34,000,000
Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amounts of derivative contracts entered into for trading account purposes	17,600,000,000		17,600,000,000		17,600,000,000
Foreign Currency and Other Option and Futures Contracts [Member]
Derivative [Line Items]
Notional amounts of derivative contracts entered into for trading account purposes	$ 1,600,000,000		$ 1,600,000,000		$ 1,300,000,000

Derivative Financial Instrume65

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, 2015	Dec. 31, 2014
Derivative [Line Items]
Notional Amount	$ 1,400,000,000	$ 1,400,000,000
Average Maturity (in years)	1 year 10 months 24 days	2 years 8 months 12 days
Weighted-Average Rate, Fixed	4.42%	4.42%
Weighted-Average Rate, Variable	1.29%	1.19%

Derivative Financial Instrume66

Derivative Financial Instruments - Information about Fair Values of Derivative Instruments in Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Asset derivatives, Fair value	$ 361,275	$ 338,855
Liability derivatives, Fair value	242,495	212,059
Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives, Fair value	299,594	264,876
Liability derivatives, Fair value	237,353	207,842
Fair Value Hedges [Member] | Derivatives Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives, Fair value	61,681	73,979
Liability derivatives, Fair value	5,142	4,217
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	60,782	73,251
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	26	754
Liability derivatives, Fair value	4,162	4,330
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	899	728
Liability derivatives, Fair value	5,142	4,217
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	17,832	17,396
Liability derivatives, Fair value	185	49
Interest Rate Contracts [Member] | Derivatives Not Designated and Qualifying as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives, Fair value	268,332	215,614
Liability derivatives, Fair value	221,626	173,513
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	13,404	31,112
Liability derivatives, Fair value	$ 11,380	$ 29,950

Derivative Financial Instrume67

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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives not designated as hedging instruments, Derivatives	$ 6,561	$ (649)	$ 8,115	$ (5,383)
Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives not designated as hedging instruments, Derivatives	4,120	132	6,552	1,214
Foreign Exchange and Other Option and Futures Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives not designated as hedging instruments, Derivatives	2,441	(781)	1,563	(6,597)
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	(2,719)	(16,792)	(12,469)	(26,627)
Derivatives in fair value hedging relationships, Hedged item	$ 2,382	$ 16,380	$ 11,495	$ 25,658

Variable Interest Entities an68

Variable Interest Entities and Asset Securitizations - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Variable Interest Entity Disclosure [Abstract]
Residential mortgage loans securitized with Ginnie Mae	$ 15,000,000	$ 35,000,000	$ 51,000,000	$ 110,000,000
Carrying value of loans in the Securitization trusts	84,000,000		84,000,000		$ 98,000,000
Combined outstanding principal amount of mortgage-backed securities issued by qualified special purpose trust held by unrelated parties	13,000,000		13,000,000		15,000,000
Other assets for its "investment" in the common securities recognized by the company of various trusts	24,000,000		24,000,000		34,000,000
Total assets of real estate partnerships in which the company invested	1,200,000,000		1,200,000,000		1,200,000,000
Maximum exposure to loss of investments in real estate partnerships	301,000,000		301,000,000		243,000,000
Unfunded commitments included in company's maximum exposure to loss of investments in real estate partnerships	85,000,000		85,000,000		$ 56,000,000
Investments amortized to income tax expense	10,000,000	14,000,000	31,000,000	39,000,000
Tax credits and other tax benefits recognized	$ 15,000,000	$ 18,000,000	$ 44,000,000	$ 53,000,000

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015USD ($)Source	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)Source	Sep. 30, 2014USD ($)	Dec. 31, 2014USD ($)
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		$ 28		$ 30
Fair value of securities issued by financial institutions and other entities backed by trust preferred securities	50		50		50
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	11	$ 23	53	$ 46
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	177	196	177	196	173
Assets taken in foreclosure of defaulted loans measured at fair value on a nonrecurring basis	15	21	15	21
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	106	112	106	112	94
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans measured at fair value on nonrecurring basis	$ 71	$ 84	$ 71	$ 84	$ 79
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount margin over LIBOR			4.00%
Discount rates for fair value estimations			10.00%
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount margin over LIBOR			10.00%
Discount rates for fair value estimations			90.00%
Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount margin over LIBOR			8.00%

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Estimated Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	$ 340,710	$ 308,175
Investment securities	11,159,509	9,156,932
Real estate loans held for sale	493,453	742,249
Other assets	79,539	92,129
Total assets	12,073,211	10,299,485
Trading account liabilities	233,006	203,464
Other liabilities	9,489	8,596
Total liabilities	242,495	212,060
U.S. Treasury and Federal Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	199,394	161,947
Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	6,296	8,198
Government Issued or Guaranteed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	10,714,048	8,731,123
Privately Issued Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	82	103
Collateralized Debt Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	49,876	50,316
Other Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	120,468	121,488
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	69,345	83,757
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	48,006	51,416
Investment securities	40,370	64,841
Total assets	88,376	116,257
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	40,370	64,841
Significant Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	292,704	256,759
Investment securities	11,069,181	9,041,672
Real estate loans held for sale	493,453	742,249
Other assets	61,707	74,733
Total assets	11,917,045	10,115,413
Trading account liabilities	233,006	203,464
Other liabilities	9,304	8,547
Total liabilities	242,310	212,011
Significant Observable Inputs (Level 2) [Member] | U.S. Treasury and Federal Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	199,394	161,947
Significant Observable Inputs (Level 2) [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	6,296	8,198
Significant Observable Inputs (Level 2) [Member] | Government Issued or Guaranteed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	10,714,048	8,731,123
Significant Observable Inputs (Level 2) [Member] | Other Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	120,468	121,488
Significant Observable Inputs (Level 2) [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	28,975	18,916
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	49,958	50,419
Other assets	17,832	17,396
Total assets	67,790	67,815
Other liabilities	185	49
Total liabilities	185	49
Significant Unobservable Inputs (Level 3) [Member] | Privately Issued Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	82	103
Significant Unobservable Inputs (Level 3) [Member] | Collateralized Debt Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	$ 49,876	$ 50,316

Fair Value Measurements - Chang

Fair Value Measurements - Changes in Level 3 Assets and Liabilities Measured at Estimated Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Other Assets and Other Liabilities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 11,206	$ 22,023	$ 17,347	$ 3,941
Total gains (losses) realized/unrealized:
Included in earnings	21,709	9,657	67,611	63,557
Transfers in and/or out of Level 3	(15,268)	(15,188)	(67,311)	(51,006)
Ending Balance	17,647	16,492	17,647	16,492
Changes in unrealized gains included in earnings related to assets still held at end of period	15,488	12,421	15,965	17,773
Privately Issued [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	88	119	103	1,850
Total gains (losses) realized/unrealized:
Included in other comprehensive income				272
Settlements	(6)	(7)	(21)	(2,010)
Ending Balance	82	112	82	112
Collateralized Debt Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	50,483	56,200	50,316	63,083
Total gains (losses) realized/unrealized:
Included in other comprehensive income	(472)	2,201	5,153	11,333
Settlements	(135)	(3,593)	(5,593)	(19,608)
Ending Balance	$ 49,876	$ 54,808	$ 49,876	$ 54,808

Fair Value Measurements - Quant

Fair Value Measurements - Quantitative Information Related to Significant Unobservable Inputs (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014	Jun. 30, 2015	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Privately Issued [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value	$ 82	$ 103	$ 88	$ 112	$ 119	$ 1,850
Collateralized Debt Obligations [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value	49,876	50,316	50,483	54,808	56,200	63,083
Other Assets and Other Liabilities [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value	17,647	17,347	$ 11,206	$ 16,492	$ 22,023	$ 3,941
Discounted Cash Flows [Member] | Collateralized Debt Obligations [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value	$ 49,876	$ 50,316
Loss severity	100.00%	100.00%
Discounted Cash Flows [Member] | Collateralized Debt Obligations [Member] | Weighted Average [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Probability of default	33.00%	36.00%
Discounted Cash Flows [Member] | Collateralized Debt Obligations [Member] | Minimum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Probability of default	12.00%	12.00%
Discounted Cash Flows [Member] | Collateralized Debt Obligations [Member] | Maximum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Probability of default	57.00%	57.00%
Discounted Cash Flows [Member] | Other Assets and Other Liabilities [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value	$ 17,647	$ 17,347
Discounted Cash Flows [Member] | Other Assets and Other Liabilities [Member] | Weighted Average [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Commitment expirations	38.00%	17.00%
Discounted Cash Flows [Member] | Other Assets and Other Liabilities [Member] | Minimum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Commitment expirations	0.00%	0.00%
Discounted Cash Flows [Member] | Other Assets and Other Liabilities [Member] | Maximum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Commitment expirations	66.00%	96.00%
Two Independent Pricing Quotes [Member] | Privately Issued [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value	$ 82	$ 103

Fair Value Measurements - Carry

Fair Value Measurements - Carrying Amounts and Estimated Fair Value for Financial Instrument Assets (Liabilities) (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Financial assets:
Cash and cash equivalents	$ 1,249,704		$ 1,373,357	$ 1,523,643		$ 1,672,934
Interest-bearing deposits at banks	4,713,266		6,470,867
Trading account assets	340,710		308,175
Investment securities	14,494,539		12,993,542
Loans and leases:
Allowance for credit losses	(933,798)	$ (929,987)	(919,562)	$ (918,633)	$ (917,666)	$ (916,676)
Loans and leases, net	67,606,450		65,749,394
Financial liabilities:
Noninterest-bearing deposits	(28,189,330)		(26,947,880)
Time deposits	(2,791,367)		(3,063,973)
Deposits at Cayman Islands office	(206,185)		(176,582)
Short-term borrowings	(173,783)		(192,676)
Long-term borrowings	(10,174,289)		(9,006,959)
Trading account liabilities	(233,006)		(203,464)
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets:
Cash and cash equivalents	1,193,831		1,296,923
Trading account assets	48,006		51,416
Investment securities	40,370		64,841
Significant Observable Inputs (Level 2) [Member]
Financial assets:
Cash and cash equivalents	55,873		76,434
Interest-bearing deposits at banks	4,713,266		6,470,867
Trading account assets	292,704		256,759
Investment securities	14,283,075		12,750,396
Loans and leases:
Commercial real estate loans	71,357		307,667
Residential real estate loans	4,918,613		5,189,086
Loans and leases, net	4,989,970		5,496,753
Accrued interest receivable	242,935		227,348
Financial liabilities:
Noninterest-bearing deposits	(28,189,330)		(26,947,880)
Savings deposits and NOW accounts	(41,757,661)		(43,393,618)
Time deposits	(2,810,224)		(3,086,126)
Deposits at Cayman Islands office	(206,185)		(176,582)
Short-term borrowings	(173,783)		(192,676)
Long-term borrowings	(10,219,180)		(9,139,789)
Accrued interest payable	(73,475)		(63,372)
Trading account liabilities	(233,006)		(203,464)
Other financial instruments:
Commitments to sell real estate loans	(8,379)		(7,065)
Interest rate swap agreements used for interest rate risk management	60,782		73,251
Significant Unobservable Inputs (Level 3) [Member]
Financial assets:
Investment securities	198,295		208,719
Loans and leases:
Commercial loans and leases	19,920,031		19,188,574
Commercial real estate loans	28,562,616		27,180,151
Residential real estate loans	3,384,017		3,539,970
Consumer loans	11,280,973		10,909,623
Loans and leases, net	63,147,637		60,818,318
Other financial instruments:
Commitments to originate real estate loans for sale	17,647		17,347
Other credit-related commitments	(118,656)		(119,079)
Carrying Amount [Member]
Financial assets:
Cash and cash equivalents	1,249,704		1,373,357
Interest-bearing deposits at banks	4,713,266		6,470,867
Trading account assets	340,710		308,175
Investment securities	14,494,539		12,993,542
Loans and leases:
Commercial loans and leases	20,233,177		19,461,292
Commercial real estate loans	28,720,537		27,567,569
Residential real estate loans	8,211,062		8,657,301
Consumer loans	11,375,472		10,982,794
Allowance for credit losses	(933,798)		(919,562)
Loans and leases, net	67,606,450		65,749,394
Accrued interest receivable	242,935		227,348
Financial liabilities:
Noninterest-bearing deposits	(28,189,330)		(26,947,880)
Savings deposits and NOW accounts	(41,757,661)		(43,393,618)
Time deposits	(2,791,367)		(3,063,973)
Deposits at Cayman Islands office	(206,185)		(176,582)
Short-term borrowings	(173,783)		(192,676)
Long-term borrowings	(10,174,289)		(9,006,959)
Accrued interest payable	(73,475)		(63,372)
Trading account liabilities	(233,006)		(203,464)
Other financial instruments:
Commitments to originate real estate loans for sale	17,647		17,347
Commitments to sell real estate loans	(8,379)		(7,065)
Other credit-related commitments	(118,656)		(119,079)
Interest rate swap agreements used for interest rate risk management	60,782		73,251
Estimate Fair Value [Member]
Financial assets:
Cash and cash equivalents	1,249,704		1,373,357
Interest-bearing deposits at banks	4,713,266		6,470,867
Trading account assets	340,710		308,175
Investment securities	14,521,740		13,023,956
Loans and leases:
Commercial loans and leases	19,920,031		19,188,574
Commercial real estate loans	28,633,973		27,487,818
Residential real estate loans	8,302,630		8,729,056
Consumer loans	11,280,973		10,909,623
Loans and leases, net	68,137,607		66,315,071
Accrued interest receivable	242,935		227,348
Financial liabilities:
Noninterest-bearing deposits	(28,189,330)		(26,947,880)
Savings deposits and NOW accounts	(41,757,661)		(43,393,618)
Time deposits	(2,810,224)		(3,086,126)
Deposits at Cayman Islands office	(206,185)		(176,582)
Short-term borrowings	(173,783)		(192,676)
Long-term borrowings	(10,219,180)		(9,139,789)
Accrued interest payable	(73,475)		(63,372)
Trading account liabilities	(233,006)		(203,464)
Other financial instruments:
Commitments to originate real estate loans for sale	17,647		17,347
Commitments to sell real estate loans	(8,379)		(7,065)
Other credit-related commitments	(118,656)		(119,079)
Interest rate swap agreements used for interest rate risk management	$ 60,782		$ 73,251

Commitments and Contingencies -

Commitments and Contingencies - Company's Significant Commitments (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Commitments to extend credit
Home equity lines of credit	$ 5,535,704	$ 6,194,516
Commercial real estate loans to be sold	89,374	212,257
Other commercial real estate and construction	5,356,256	4,834,699
Residential real estate loans to be sold	587,206	432,352
Other residential real estate	674,338	524,399
Commercial and other	12,144,962	11,080,856
Standby letters of credit	3,441,337	3,706,888
Commercial letters of credit	44,082	46,965
Financial guarantees and indemnification contracts	2,922,743	2,490,050
Commitments to sell real estate loans	$ 977,822	$ 1,237,294

Commitments and Contingencies75

Commitments and Contingencies - Additional Information (Detail) - USD ($)	Sep. 30, 2015	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Maximum credit risk for recourse associated with loans sold under Federal National Mortgage Association Delegated Underwriting and Servicing program	$ 2,500,000,000	$ 2,400,000,000
Range of reasonably possible losses, minimum	0
Range of reasonably possible losses, maximum	$ 40,000,000

Segment Information - Additiona

Segment Information - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Sep. 30, 2014	Jun. 30, 2015	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Net income	$ 280,401		$ 275,344		$ 808,702	$ 788,697
Impact of Changes [Member]
Segment Reporting Information [Line Items]
Revenues		$ 6,000		$ 12,000
Net income		$ 3,000		$ 5,000
Residential Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Decrease in revenues			5,000			13,000
Decrease in net income			2,000			5,000
Net income	21,150		22,749		75,462	64,680
Residential Mortgage Banking [Member] | Impact of Changes [Member]
Segment Reporting Information [Line Items]
Net income			(2,272)			(7,464)
Commercial Real Estate [Member]
Segment Reporting Information [Line Items]
Increase in revenues			5,000			13,000
Increase in net income			2,000			5,000
Net income	$ 85,312		78,676		$ 250,501	230,254
Commercial Real Estate [Member] | Impact of Changes [Member]
Segment Reporting Information [Line Items]
Net income			$ 95			$ (414)

Segment Information - Summary o

Segment Information - Summary of Prior Period Financial Information Restated (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Sep. 30, 2014	Jun. 30, 2015	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Net income (loss)	$ 280,401		$ 275,344		$ 808,702	$ 788,697
Business Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)	23,995		25,038		74,160	73,763
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)	108,422		100,705		312,926	303,637
Commercial Real Estate [Member]
Segment Reporting Information [Line Items]
Net income (loss)	85,312		78,676		250,501	230,254
Discretionary Portfolio [Member]
Segment Reporting Information [Line Items]
Net income (loss)	5,113		12,495		21,823	38,898
Residential Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)	21,150		22,749		75,462	64,680
Retail Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)	64,721		72,057		202,415	214,064
All Other [Member]
Segment Reporting Information [Line Items]
Net income (loss)	$ (28,312)		(36,376)		$ (128,585)	(136,599)
Net Income (Loss) as Previously Reported [Member]
Segment Reporting Information [Line Items]
Net income (loss)			275,344			788,697
Net Income (Loss) as Previously Reported [Member] | Business Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)			30,905			87,263
Net Income (Loss) as Previously Reported [Member] | Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)			101,740			306,863
Net Income (Loss) as Previously Reported [Member] | Commercial Real Estate [Member]
Segment Reporting Information [Line Items]
Net income (loss)			78,581			230,668
Net Income (Loss) as Previously Reported [Member] | Discretionary Portfolio [Member]
Segment Reporting Information [Line Items]
Net income (loss)			8,279			34,538
Net Income (Loss) as Previously Reported [Member] | Residential Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)			25,021			72,144
Net Income (Loss) as Previously Reported [Member] | Retail Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)			32,901			94,646
Net Income (Loss) as Previously Reported [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Net income (loss)			(2,083)			(37,425)
Impact of Changes [Member]
Segment Reporting Information [Line Items]
Net income (loss)		$ 3,000		$ 5,000
Impact of Changes [Member] | Business Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)			(5,867)			(13,500)
Impact of Changes [Member] | Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)			(1,035)			(3,226)
Impact of Changes [Member] | Commercial Real Estate [Member]
Segment Reporting Information [Line Items]
Net income (loss)			95			(414)
Impact of Changes [Member] | Discretionary Portfolio [Member]
Segment Reporting Information [Line Items]
Net income (loss)			4,216			4,360
Impact of Changes [Member] | Residential Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)			(2,272)			(7,464)
Impact of Changes [Member] | Retail Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)			39,156			119,418
Impact of Changes [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Net income (loss)			$ (34,293)			$ (99,174)

Segment Information - Informati

Segment Information - Information about Company's Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Net income (loss)	$ 280,401	$ 275,344	$ 808,702	$ 788,697
Business Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)	23,995	25,038	74,160	73,763
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)	108,422	100,705	312,926	303,637
Commercial Real Estate [Member]
Segment Reporting Information [Line Items]
Net income (loss)	85,312	78,676	250,501	230,254
Discretionary Portfolio [Member]
Segment Reporting Information [Line Items]
Net income (loss)	5,113	12,495	21,823	38,898
Residential Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)	21,150	22,749	75,462	64,680
Retail Banking [Member]
Segment Reporting Information [Line Items]
Net income (loss)	64,721	72,057	202,415	214,064
All Other [Member]
Segment Reporting Information [Line Items]
Net income (loss)	(28,312)	(36,376)	(128,585)	(136,599)
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	1,132,526	1,120,170	3,412,472	3,322,236
Operating Segments [Member] | Business Banking [Member]
Segment Reporting Information [Line Items]
Total revenues	112,650	113,425	332,341	337,929
Operating Segments [Member] | Commercial Banking [Member]
Segment Reporting Information [Line Items]
Total revenues	270,554	247,282	774,392	748,978
Operating Segments [Member] | Commercial Real Estate [Member]
Segment Reporting Information [Line Items]
Total revenues	181,478	170,772	535,909	500,814
Operating Segments [Member] | Discretionary Portfolio [Member]
Segment Reporting Information [Line Items]
Total revenues	13,773	24,835	49,724	79,404
Operating Segments [Member] | Residential Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Total revenues	99,518	104,092	310,843	299,237
Operating Segments [Member] | Retail Banking [Member]
Segment Reporting Information [Line Items]
Total revenues	308,520	316,052	914,484	934,386
Operating Segments [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Total revenues	146,033	143,712	494,779	421,488
Intersegment Activity Eliminated in Consolidated Totals [Member] | Business Banking [Member]
Segment Reporting Information [Line Items]
Total revenues	1,167	1,082	3,334	3,359
Intersegment Activity Eliminated in Consolidated Totals [Member] | Commercial Banking [Member]
Segment Reporting Information [Line Items]
Total revenues	1,097	1,281	3,281	3,834
Intersegment Activity Eliminated in Consolidated Totals [Member] | Commercial Real Estate [Member]
Segment Reporting Information [Line Items]
Total revenues	469	442	978	1,315
Intersegment Activity Eliminated in Consolidated Totals [Member] | Discretionary Portfolio [Member]
Segment Reporting Information [Line Items]
Total revenues	(5,365)	(5,478)	(16,184)	(15,799)
Intersegment Activity Eliminated in Consolidated Totals [Member] | Residential Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Total revenues	12,918	12,875	36,741	34,395
Intersegment Activity Eliminated in Consolidated Totals [Member] | Retail Banking [Member]
Segment Reporting Information [Line Items]
Total revenues	3,292	3,735	9,688	11,137
Intersegment Activity Eliminated in Consolidated Totals [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Total revenues	$ (13,578)	$ (13,937)	$ (37,838)	$ (38,241)

Segment Information - Summary79

Segment Information - Summary of Segment Information (Detail) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Segment Reporting Information [Line Items]
Average Assets	$ 97,345	$ 92,143	$ 89,952
Business Banking [Member]
Segment Reporting Information [Line Items]
Average Assets	5,321	5,281	5,287
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Average Assets	24,041	22,892	22,805
Commercial Real Estate [Member]
Segment Reporting Information [Line Items]
Average Assets	18,632	17,370	17,187
Discretionary Portfolio [Member]
Segment Reporting Information [Line Items]
Average Assets	23,153	20,798	20,306
Residential Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Average Assets	3,007	3,076	3,016
Retail Banking [Member]
Segment Reporting Information [Line Items]
Average Assets	10,912	10,449	10,348
All Other [Member]
Segment Reporting Information [Line Items]
Average Assets	$ 12,279	$ 12,277	$ 11,003

Segment Information - Summary80

Segment Information - Summary of Segment Information (Parenthetical) (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Taxable-equivalent adjustment	$ 6,248,000	$ 5,841,000	$ 18,106,000	$ 17,635,000
Commercial Real Estate [Member]
Segment Reporting Information [Line Items]
Average assets		$ 246,000,000		$ 246,000,000
Residential Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Average assets					$ 257,000,000

Relationship with Bayview Len81

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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Bayview Lending Group and Bayview Financial [Member]
Schedule of Equity Method Investments [Line Items]
Outstanding principal balances of mortgage servicing rights	$ 4,300		$ 4,300		$ 4,800
Revenues from servicing	$ 6	$ 6	$ 17	$ 20
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	$ 33		$ 33
Bayview Financial [Member]
Schedule of Equity Method Investments [Line Items]
Revenues from servicing	26	$ 29	91	$ 82
Outstanding principal balances of residential mortgage loans from Bayview Financial	39,500		39,500		41,300
Investment securities in held-to-maturity portfolio securitized by Bayview Financial	$ 187		$ 187		$ 202

Sale of Trust Accounts - Additi

Sale of Trust Accounts - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended	12 Months Ended
	Apr. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Sep. 30, 2014	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Gain on sale of business net of tax	$ 23
Gain on sale of business before tax	45
Goodwill recorded	$ 11
Revenue on sale of business		$ 9	$ 8	$ 26	$ 34