People's United Financial (PBCT) 10-Q12 Nov 192019 Q3 Quarterly reportFinancial data

Company Profile

Cover Page

Cover Page - shares	9 Months Ended
Cover Page - shares	Sep. 30, 2019	Oct. 31, 2019
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Document Transition Report	false
Entity Registrant Name	PEOPLE’S UNITED FINANCIAL, INC.
Entity File Number	001-33326
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-8447891
Entity Address, Address Line One	850 Main Street
Entity Address, City or Town	Bridgeport
Entity Address, State or Province	CT
Entity Address, Postal Zip Code	06604
City Area Code	(203)
Local Phone Number	338-7171
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		399,365,374
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001378946
Current Fiscal Year End Date	--12-31
Common Stock, $0.01 par value per share
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	PBCT
Security Exchange Name	NASDAQ
Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock, Series A, $0.01 par value per share
Entity Information [Line Items]
Title of 12(b) Security	Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock, Series A, $0.01 par value per share
Trading Symbol	PBCTP
Security Exchange Name	NASDAQ

Consolidated Statements of Cond

Consolidated Statements of Condition - (Unaudited) - USD ($) shares in Millions, $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Assets
Cash and due from banks	$ 635.2	$ 665.7
Short-term investments	157.8	266.3
Total cash and cash equivalents (note 3)	793	932
Securities (note 3):
Trading debt securities, at fair value	9.3	8.4
Equity securities, at fair value	7.8	8.1
Debt securities available-for-sale, at fair value	2,978.7	3,121
Debt securities held-to-maturity, at amortized cost (fair value of $3.97 billion and $3.78 billion)	3,805.4	3,792.3
Federal Home Loan Bank and Federal Reserve Bank stock, at cost	334	303.4
Total securities	7,135.2	7,233.2
Loans held-for-sale	24.8	19.5
Loans (notes 4 and 14):
Loans	38,781.4	35,241.4
Less allowance for loan losses	(246)	(240.4)
Total loans, net	38,535.4	35,001
Goodwill (notes 2 and 7)	2,868.1	2,685.7
Bank-owned life insurance	505.6	467
Premises and equipment, net	258.5	267.3
Other acquisition-related intangible assets (notes 2 and 7)	196.8	180
Other assets (notes 1, 4, 12 and 14)	1,754.4	1,091.6
Total assets	52,071.8	47,877.3
Deposits:
Non-interest-bearing	9,129.3	8,543
Savings	4,616.6	4,116.5
Interest-bearing checking and money market	16,727.2	16,583.3
Time	8,100.4	6,916.2
Total deposits	38,573.5	36,159
Borrowings:
Federal Home Loan Bank advances	2,948.5	2,404.5
Federal funds purchased	1,365	845
Customer repurchase agreements	315.6	332.9
Other borrowings	0	11
Total borrowings	4,629.1	3,593.4
Notes and debentures	915.7	895.8
Other liabilities (notes 1, 12 and 14)	822.8	695.2
Total liabilities	44,941.1	41,343.4
Commitments and contingencies (notes 1, 9 and 14)
Stockholders’ Equity (notes 2, 5, 8 and 15)
Preferred stock ($0.01 par value; 50.0 million shares authorized; 10.0 million shares issued and outstanding at both dates)	244.1	244.1
Common stock ($0.01 par value; 1.95 billion shares authorized; 487.6 million shares and 466.3 million shares issued)	4.9	4.7
Additional paid-in capital	6,901.5	6,549.3
Retained earnings	1,449.3	1,284.8
Unallocated common stock of Employee Stock Ownership Plan, at cost (6.0 million shares and 6.3 million shares)	(124.7)	(130.1)
Accumulated other comprehensive loss	(182.3)	(256.8)
Treasury stock, at cost (89.0 million shares at both dates)	(1,162.1)	(1,162.1)
Total stockholders’ equity	7,130.7	6,533.9
Total liabilities and stockholders’ equity	$ 52,071.8	$ 47,877.3
Common stock, shares issued (in shares)	487.6	466.3
Commercial
Loans (notes 4 and 14):
Loans	$ 27,468.4	$ 25,077.7
Less allowance for loan losses	(216.8)	(209.5)
Retail
Loans (notes 4 and 14):
Loans	11,313	10,163.7
Less allowance for loan losses	(29.2)	(30.9)
Commercial real estate \| Commercial
Loans (notes 4 and 14):
Loans	12,186.9	11,649.6
Commercial and industrial \| Commercial
Loans (notes 4 and 14):
Loans	10,545.9	9,088.9
Equipment financing \| Commercial
Loans (notes 4 and 14):
Loans	4,735.6	4,339.2
Residential mortgage \| Retail
Loans (notes 4 and 14):
Loans	9,308.7	8,154.2
Home equity and other consumer \| Retail
Loans (notes 4 and 14):
Loans	$ 2,004.3	$ 2,009.5

Consolidated Statements of Co_2

Consolidated Statements of Condition - (Unaudited) (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Securities held to maturity, at fair value	$ 3,971.5	$ 3,775.9
Preferred stock, par value (USD per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Preferred stock, shares issued (in shares)	10,000,000	10,000,000
Preferred stock, shares outstanding (in shares)	10,000,000	10,000,000
Common stock, par value (USD per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,950,000,000	1,950,000,000
Common stock, shares issued (in shares)	487,600,000	466,300,000
Unallocated common stock of Employee Stock Ownership Plan (in shares)	6,010,806	6,300,000
Treasury stock (in shares)	89,000,000	89,000,000

Consolidated Statements of Inco

Consolidated Statements of Income - (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Interest and dividend income:
Commercial real estate	$ 136.6	$ 114.7	$ 409.2	$ 333.2
Residential mortgage	84.7	56	240.9	166
Home equity and other consumer	24.7	22	75.4	64.2
Total interest on loans	424.7	342.1	1,241.2	984.6
Securities	44.7	46.6	138.7	135.7
Short-term investments	1.3	1.1	3.8	3.6
Loans held-for-sale	0.2	0.2	0.6	0.6
Total interest and dividend income	470.9	390	1,384.3	1,124.5
Interest expense:
Deposits	92.2	56.9	270	145.5
Borrowings	21.5	18.2	58.6	50.9
Notes and debentures	8.5	8.5	26.1	24.7
Total interest expense	122.2	83.6	354.7	221.1
Net interest income	348.7	306.4	1,029.6	903.4
Provision for loan losses (note 4)	7.8	8.2	21	20.1
Net interest income after provision for loan losses	340.9	298.2	1,008.6	883.3
Non-interest income:
Operating lease income (note 14)	13		38.4
Operating lease income (note 14)		11		32.9
Commercial banking lending fees	11.8	7.9	29.8	27.7
Insurance revenue	10.3	9.8	29.5	27.9
Cash management fees	7.3	7	21.2	20.6
Brokerage commissions	2.6	3.2	8	9.5
Other non-interest income (note 3)	16.7	11.1	50.5	33.7
Total non-interest income	106	92.3	306.9	277.6
Non-interest expense:
Compensation and benefits	158.1	135.7	474.8	411.4
Occupancy and equipment	45	41.6	133.7	123.6
Professional and outside services	23.7	17	68.6	56.2
Expense related to operating leases	9.9		29.2
Expense related to operating leases		8.9		26.6
Amortization of other acquisition-related intangible assets (note 7)	8	4.9	22.7	14.9
Regulatory assessments	5.3	10	18.8	30.5
Other non-interest expense	31.4	23.2	89.2	70.2
Total non-interest expense	281.4	241.3	837	733.4
Income before income tax expense	165.5	149.2	478.5	427.5
Income tax expense (note 1)	30.4	32.2	95.5	92.4
Net income	135.1	117	383	335.1
Preferred stock dividend	3.5	3.5	10.5	10.5
Net income available to common shareholders	$ 131.6	$ 113.5	$ 372.5	$ 324.6
Earnings per common share (note 6):
Basic (USD per share)	$ 0.34	$ 0.33	$ 0.97	$ 0.95
Diluted (USD per share)	$ 0.33	$ 0.33	$ 0.96	$ 0.94
Bank service charges
Non-interest income:
Fees	$ 27	$ 24.9	$ 78.6	$ 73
Investment management fees
Non-interest income:
Fees	17.3	17.4	50.9	52.3
Commercial and industrial
Interest and dividend income:
Interest and fee income	113.4	93.2	328.7	265.6
Equipment financing
Interest and dividend income:
Interest and fee income	$ 65.3	$ 56.2	$ 187	$ 155.6

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 135.1	$ 117	$ 383	$ 335.1
Other comprehensive income (loss), net of tax:
Net actuarial loss and prior service credit related to pension and other postretirement plans	1	1.5	3.9	4.5
Net unrealized gains and losses on debt securities available-for-sale	8.6	(12)	66.2	(56.3)
Amortization of unrealized losses on debt securities transferred to held-to-maturity	0.8	0.7	2	2.3
Net unrealized gains and losses on derivatives accounted for as cash flow hedges	0.3	(0.3)	2.4	(2.3)
Total other comprehensive income (loss), net of tax (note 5)	10.7	(10.1)	74.5	(51.8)
Total comprehensive income	$ 145.8	$ 106.9	$ 457.5	$ 283.3

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - (Unaudited) - USD ($) $ in Millions	Total	Preferred Stock	Common Stock, $0.01 par value per share	Additional Paid-In Capital	Retained Earnings	Unallocated ESOP Common Stock	Accumulated Other Comprehensive Loss	Treasury Stock	BSB Bancorp	BSB BancorpCommon Stock, $0.01 par value per share	BSB BancorpAdditional Paid-In Capital
Beginning Balance at Dec. 31, 2017	$ 5,819.9	$ 244.1	$ 4.4	$ 6,012.3	$ 1,040.2	$ (137.3)	$ (181.7)	$ (1,162.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	335.1				335.1
Total other comprehensive income (loss), net of tax (note 5)	(51.8)						(51.8)
Common stock issued in BSB Bancorp acquisition (note 2)									$ 0
Cash dividends on common stock	(178.8)				(178.8)
Cash dividend on preferred stock	(10.5)				(10.5)
Restricted stock and performance-based share awards	10.8			10.8
Employee Stock Ownership Plan common stock committed to be released (note 8)	4.8				(0.6)	5.4
Common stock repurchased and retired upon vesting of restricted stock awards	(2.4)				(2.4)
Stock options exercised	31.2			31.2
Ending Balance at Sep. 30, 2018	5,958.9	244.1	4.4	6,054.3	1,220.9	(131.9)	(270.8)	(1,162.1)
Beginning Balance at Jun. 30, 2018	5,900.2	244.1	4.4	6,040.3	1,167.9	(133.7)	(260.7)	(1,162.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	117				117
Total other comprehensive income (loss), net of tax (note 5)	(10.1)						(10.1)
Cash dividends on common stock	(60.1)				(60.1)
Cash dividend on preferred stock	(3.5)				(3.5)
Restricted stock and performance-based share awards	3.4			3.4
Employee Stock Ownership Plan common stock committed to be released (note 8)	1.5				(0.3)	1.8
Common stock repurchased and retired upon vesting of restricted stock awards	(0.1)				(0.1)
Stock options exercised	10.6			10.6
Ending Balance at Sep. 30, 2018	5,958.9	244.1	4.4	6,054.3	1,220.9	(131.9)	(270.8)	(1,162.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Increase in aggregate allowance levels as a result of the ASU adoption	0.6				37.9		(37.3)
Beginning Balance at Dec. 31, 2018	6,533.9	244.1	4.7	6,549.3	1,284.8	(130.1)	(256.8)	(1,162.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	383				383
Total other comprehensive income (loss), net of tax (note 5)	74.5						74.5
Common stock issued in BSB Bancorp acquisition (note 2)	324.5								$ 324.3	$ 0.2	$ 324.3
Cash dividends on common stock	(204.9)				(204.9)
Cash dividend on preferred stock	(10.5)				(10.5)
Restricted stock and performance-based share awards	10.9			10.9
Employee Stock Ownership Plan common stock committed to be released (note 8)	4.2				(1.2)	5.4
Common stock repurchased and retired upon vesting of restricted stock awards	(1.9)				(1.9)
Stock options exercised	17			17
Ending Balance at Sep. 30, 2019	7,130.7	244.1	4.9	6,901.5	1,449.3	(124.7)	(182.3)	(1,162.1)
Beginning Balance at Jun. 30, 2019	7,046.2	244.1	4.9	6,890.7	1,388.1	(126.5)	(193)	(1,162.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	135.1				135.1
Total other comprehensive income (loss), net of tax (note 5)	10.7						10.7
Cash dividends on common stock	(69.9)				(69.9)
Cash dividend on preferred stock	(3.5)				(3.5)
Restricted stock and performance-based share awards	6			6
Employee Stock Ownership Plan common stock committed to be released (note 8)	1.4				(0.4)	1.8
Common stock repurchased and retired upon vesting of restricted stock awards	(0.1)				(0.1)
Stock options exercised	4.8			4.8
Ending Balance at Sep. 30, 2019	$ 7,130.7	$ 244.1	$ 4.9	$ 6,901.5	$ 1,449.3	$ (124.7)	$ (182.3)	$ (1,162.1)

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Stockholders' Equity - (Unaudited) (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Retained Earnings
Cash dividends on common stock (USD per share)	$ 0.1775	$ 0.1750	$ 0.53	$ 0.5225

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash Flows from Operating Activities:
Net income	$ 383	$ 335.1
Adjustments to reconcile net income to net cash provided by operating activities:
Expense related to operating leases	29.2
Expense related to operating leases		26.6
Depreciation and amortization of premises and equipment	29	26.8
Amortization of other acquisition-related intangible assets	22.7	14.9
Provision for loan losses	21	20.1
Expense related to share-based awards	18.5	14.8
Employee Stock Ownership Plan common stock committed to be released	4.2	4.8
Net security gains	(0.1)	(0.2)
Net gains on sales of residential mortgage loans	(1.5)	(0.9)
Originations of loans held-for-sale	(124.8)	(126.8)
Proceeds from sales of loans held-for-sale	120.6	129.1
Net increase in trading debt securities	(0.9)	0
Excess income tax benefits from stock option exercises	0.3	1.4
Net changes in other assets and other liabilities	(494.9)	14.1
Net cash provided by operating activities	6.3	459.8
Cash Flows from Investing Activities:
Proceeds from sales of equity securities	0.9	1.9
Proceeds from principal repayments and maturities of debt securities available-for-sale	350	346.9
Proceeds from sales of debt securities available-for-sale	311.8	0.1
Proceeds from principal repayments and maturities of debt securities held-to-maturity	121.3	142.1
Purchases of debt securities available-for-sale	(305.1)	(625.1)
Purchases of debt securities held-to-maturity	(153.5)	(309.6)
Net redemptions of Federal Reserve Bank stock	26.1	7.3
Net purchases of Federal Home Loan Bank stock	(25)	(7.4)
Proceeds from sales of loans	23.6	11.9
Net principal (disbursements) collections of loans	(881.9)	423.3
Purchases of loans	(50.7)	0
Purchases of premises and equipment	(19.7)	(17.3)
Purchases of leased equipment, net	(34.6)	(31.3)
Proceeds from sales of real estate owned	10.4	8.1
Return of premium on bank-owned life insurance, net	1.2	0.8
Net cash acquired (paid) in acquisitions	48.7	(35.8)
Net cash used in investing activities	(576.5)	(84.1)
Cash Flows from Financing Activities:
Net increase in deposits	295.8	153.9
Net increase (decrease) in borrowings with terms of three months or less	417.5	(252.8)
Repayments of borrowings with terms of more than three months	(76.8)	(456.6)
Cash dividends paid on common stock	(204.9)	(178.8)
Cash dividends paid on preferred stock	(10.5)	(10.5)
Repurchases of common stock	(1.9)	(2.4)
Proceeds from stock options exercised	12.9	27.2
Contingent consideration payments	(0.9)	(0.3)
Net cash provided by (used in) financing activities	431.2	(720.3)
Net decrease in cash, cash equivalents and restricted cash	(139)	(344.6)
Cash, cash equivalents and restricted cash at beginning of period	932	882.6
Cash, cash equivalents and restricted cash at end of period	793	538
Supplemental Information:
Interest payments	356.6	214.6
Income taxes payments	86.5	41.2
Significant non-cash transactions:
Right-of-use assets obtained in exchange for lessee operating lease liabilities	30.3	0
Real estate properties acquired by foreclosure	17.1	5.3
Unsettled purchases of securities	2.1	3.8
Assets acquired and liabilities assumed in acquisitions:
Non-cash assets, excluding goodwill and other acquisition-related intangibles	2,893.6	69.1
Liabilities	2,862.2	1.4
Common stock issued in BSB Bancorp acquisition	324.5
BSB Bancorp
Assets acquired and liabilities assumed in acquisitions:
Common stock issued in BSB Bancorp acquisition	$ 324.3	$ 0

General

General	9 Months Ended
General	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
General	NOTE 1. GENERAL In the opinion of management, the accompanying unaudited consolidated financial statements of People’s United Financial, Inc. (“People’s United” or the “Company”) have been prepared to reflect all adjustments necessary to present fairly the financial position and results of operations as of the dates and for the periods shown. All significant intercompany transactions and balances are eliminated in consolidation. In preparing the consolidated financial statements, management is required to make significant estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses. Actual results could differ from management’s current estimates, as a result of changing conditions and future events. Several accounting estimates are particularly critical and are susceptible to significant near-term change, including the allowance for loan losses and asset impairment judgments, such as the recoverability of goodwill and other intangible assets. These accounting estimates are reviewed with the Audit Committee of the Board of Directors. The judgments used by management in applying critical accounting policies may be affected by economic conditions, which may result in changes to future financial results. For example, subsequent evaluations of the loan portfolio, in light of the factors then prevailing, may result in significant changes in the allowance for loan losses in future periods, and the inability to collect outstanding principal may result in increased loan losses. Certain information and footnote disclosures normally included in consolidated financial statements prepared in conformity with U.S. generally accepted accounting principles (“GAAP”) have been omitted or condensed. As a result, the accompanying consolidated financial statements should be read in conjunction with People’s United’s Annual Report on Form 10-K for the year ended December 31, 2018. The results of operations for the three and nine months ended September 30, 2019 are not necessarily indicative of the results of operations that may be expected for the entire year or any other interim period. Note 1 to People’s United’s audited consolidated financial statements included in the Annual Report on Form 10-K for the year ended December 31, 2018, as supplemented by the Quarterly Report for the periods ended March 31, 2019 and June 30, 2019 and this Quarterly Report for the period ended September 30, 2019, provides disclosure of People’s United’s significant accounting policies. People’s United holds ownership interests in limited partnerships formed to develop and operate affordable housing units for lower income tenants throughout its franchise area. The underlying partnerships, which are considered variable interest entities, are not consolidated into the Company’s Consolidated Financial Statements. These investments have historically played a role in enabling People’s United Bank, National Association (the “Bank”) to meet its Community Reinvestment Act requirements while, at the same time, providing federal income tax credits. Affordable housing investments, including all legally binding commitments to fund future investments, are included in other assets in the Consolidated Statements of Condition ($368.7 million and $304.1 million at September 30, 2019 and December 31, 2018, respectively). Included in other liabilities in the Consolidated Statements of Condition is a liability for all legally binding unfunded commitments to fund future investments ($145.5 million and $119.7 million at those dates). The cost of the Company’s investments is amortized on a straight-line basis over the period during which the related federal income tax credits are realized (generally 10 years). Amortization expense, which is included as a component of income tax expense, totaled $6.4 million and $4.8 million for the three months ended September 30, 2019 and 2018, respectively, and $18.5 million and $14.0 million for the nine months ended September 30, 2019 and 2018, respectively.

Acquisitions

Acquisitions	9 Months Ended
Acquisitions	Sep. 30, 2019
Business Combinations [Abstract]
Acquisitions	NOTE 2. ACQUISITIONS BSB Bancorp, Inc. Effective April 1, 2019, People’s United completed its acquisition of BSB Bancorp, Inc. (“BSB Bancorp”) based in Belmont, Massachusetts. The fair value of the consideration transferred in the BSB Bancorp acquisition totaled $324.5 million and consisted of 19.7 million shares of People’s United common stock. At the acquisition date, BSB Bancorp operated six branches in the greater Boston area. The assets acquired and liabilities assumed in this transaction were recorded by People’s United at their estimated fair values as of the effective date and People’s United’s results of operations for the nine months ended September 30, 2019 include the results of BSB Bancorp beginning with the effective date. The excess of the purchase price over the estimated fair value of the net assets acquired was recorded as goodwill, which was allocated to the Commercial Banking and Retail Banking segments. Merger-related expenses related to the BSB Bancorp acquisition recorded during the nine months ended September 30, 2019 totaled $7.3 million, including: (i) fees for investment advisory, legal, accounting and valuation services; (ii) costs associated with contract terminations and branch closings; and (iii) compensatory charges. The acquisition-date estimated fair values of the assets acquired and liabilities assumed in the acquisition of BSB Bancorp are s ummarized as follows: (in millions) Assets: Cash and cash equivalents $ 108.7 Securities 175.8 Loans 2,642.9 Goodwill 144.9 Core deposit intangible 39.5 Premises and equipment 8.3 Bank-owned life insurance 36.8 Other assets 29.8 Total assets $ 3,186.7 Liabilities: Deposits $ 2,118.7 Borrowings 696.6 Other liabilities 46.9 Total liabilities $ 2,862.2 Total purchase price $ 324.5 Net deferred tax liabilities totaling $3.8 million were established in connection with recording the related purchase accounting adjustments (other than goodwill). Fair value adjustments to assets acquired (other than loans, see Note 4) and liabilities assumed are generally amortized on a straight-line basis over periods consistent with the average life, useful life and/or contractual term of the related assets and liabilities. The preceding summary includes adjustments to record the acquired assets and assumed liabilities at their respective fair values based on management’s best estimate using the information available at the time of this acquisition. While there may be changes in the respective acquisition-date fair values of certain balance sheet amounts and other items, management does not expect that such changes, if any, will be material. Fair values of the major categories of assets acquired and liabilities assumed were determined as follows: Cash and Cash Equivalents The fair values of cash and cash equivalents approximate the respective carrying amounts because the instruments are payable on demand or have short-term maturities. Securities The fair values of securities acquired were based on quoted market prices. If a quoted market price for a certain security was not available, then a quoted price for a similar security in active markets was used to estimate fair value. Loans Loans acquired in this acquisition were recorded at fair value with no carryover from BSB Bancorp’s previously established allowance for loan losses. Fair value of the loans was determined using market participant assumptions in estimating the amount and timing of both principal and interest cash flows expected to be collected as adjusted for an estimate of future credit losses and prepayments and then applying a market-based discount rate to those cash flow. The acquired loans were evaluated upon the acquisition date and subsequently classified as purchased performing (see Note 4). Such loans had a fair value of $2.64 billion and an outstanding principal balance of $2.69 billion , resulting in a discount that will be accreted over the remaining lives of the loans. Included in the Consolidated Statements of Income for the nine months ended September 30, 2019 is approxima tely $42.2 million of inte rest income attributable to BSB Bancorp since the acquisition date. Core Deposit Intangible The core deposit intangible represents the value of the relationships with deposit customers. The fair value was estimated based on a discounted cash flow methodology that gave appropriate consideration to expected customer attrition rates, net maintenance costs of the deposit base, the alternative cost of funds and the interest cost associated with customer deposits. The core deposit intangible will be amortized using an accelerated amortization method over a 10-year period, reflective of the manner in which the related benefit attributable to the deposits will be recognized. Deposits The fair values of acquired savings and transaction deposit accounts were assumed to approximate the respective carrying amounts as these accounts have no stated maturity and are payable on demand. Time deposits were valued based on the present value of the contractual cash flows over the remaining period to maturity using a market rate. Borrowings The fair values of Federal Home Loan Bank advances and other borrowings represent contractual repayments discounted using interest rates currently available on borrowings with similar characteristics and remaining maturities. The following table presents selected unaudited pro forma financial information of the Company reflecting the acquisition of BSB Bancorp assuming the acquisition was completed as of the beginning of the respective periods: Nine Months Ended (in millions, except per common share data) 2019 2018 Selected Financial Results: Net interest income $ 1,044.7 $ 949.1 Provision for loan losses 21.0 20.1 Non-interest income 308.2 281.3 Non-interest expense 837.5 756.7 Net income 395.5 355.6 Net income applicable to common shareholders 385.0 345.1 Earnings per common share: Basic $ 0.98 $ 0.96 Diluted 0.98 0.95 The selected unaudited pro forma financial information is presented for illustrative purposes only and is not necessarily indicative of the financial results of the combined companies had the acquisition actually been completed at the beginning of the periods presented, nor does it indicate future results for any other interim or full-year period. Merger-related expenses attributable to the acquisition that were incurred by People’s United and BSB Bancorp during the nine months ended September 30, 2019 (none in 2018) ar e not reflected in the selected unaudited pro forma financial information. Pro forma basic and diluted earnings per common share were calculated using People’s United’s actual weighted-average common shares outstanding for the periods presented, plus the incremental common shares issued, assuming the acquisition occurred at the beginning of the periods presented. VAR Technology Finance Effective January 2, 2019, the Bank completed its acquisition of VAR Technology Finance ("VAR"), a leasing and financing company headquartered in Mesquite, Texas. The fair value of the consideration transferred in the VAR acquisition consisted of $60.0 million in cash. Merger-related expenses totaling $1.9 million relating to this transaction were recorded during the nine months ended September 30, 2019.

Cash and Cash Equivalents and S

Cash and Cash Equivalents and Securities	9 Months Ended
Cash and Cash Equivalents and Securities	Sep. 30, 2019
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents and Securities	NOTE 3. CASH AND CASH EQUIVALENTS AND SECURITIES Included in short-term investments are interest-bearing deposits at the Federal Reserve Bank of New York (the “FRB-NY”) totaling $50.6 million at September 30, 2019 and $234.0 million at December 31, 2018. These deposits represent an alternative to overnight federal funds sold and yielded 1.80% and 2.40% at September 30, 2019 and December 31, 2018, respectively. The amortized cost, gross unrealized gains and losses, and fair value of People’s United’s debt securities available-for-sale and debt securities held-to-maturity are as follows: As of September 30, 2019 (in millions) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Debt securities available-for-sale: U.S. Treasury and agency $ 690.6 $ 0.4 $ (2.9) $ 688.1 GSE (1) mortgage-backed securities 2,269.7 24.3 (3.4) 2,290.6 Total debt securities available-for-sale $ 2,960.3 $ 24.7 $ (6.3) $ 2,978.7 Debt securities held-to-maturity: State and municipal $ 2,432.3 $ 148.3 $ (0.3) $ 2,580.3 GSE mortgage-backed securities 1,291.7 17.0 (0.1) 1,308.6 Corporate 79.9 1.4 (0.2) 81.1 Other 1.5 — — 1.5 Total debt securities held-to-maturity $ 3,805.4 $ 166.7 $ (0.6) $ 3,971.5 1. Government sponsored enterprise As of December 31, 2018 (in millions) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Debt securities available-for-sale: U.S. Treasury and agency $ 699.0 $ 0.1 $ (21.1) $ 678.0 GSE mortgage-backed securities 2,486.6 4.6 (48.2) 2,443.0 Total debt securities available-for-sale $ 3,185.6 $ 4.7 $ (69.3) $ 3,121.0 Debt securities held-to-maturity: State and municipal $ 2,352.4 $ 35.4 $ (18.4) $ 2,369.4 GSE mortgage-backed securities 1,367.5 — (33.2) 1,334.3 Corporate 70.9 0.5 (0.7) 70.7 Other 1.5 — — 1.5 Total debt securities held-to-maturity $ 3,792.3 $ 35.9 $ (52.3) $ 3,775.9 At September 30, 2019 and December 31, 2018, debt securities available-for-sale with fair values of $2.07 billion and $2.20 billion, respectively, and debt securities held-to-maturity with amortized costs of $1.65 billion and $1.49 billion, respectively, were pledged as collateral for public deposits and for other purposes. The following table is a summary of the amortized cost and fair value of debt securities as of September 30, 2019, based on remaining period to contractual maturity. Information for GSE mortgage-backed securities is based on the final contractual maturity dates without considering repayments and prepayments. Available-for-Sale Held-to-Maturity (in millions) Amortized Cost Fair Value Amortized Cost Fair Value U.S. Treasury and agency: Within 1 year $ 158.9 $ 158.9 $ — $ — After 1 but within 5 years 531.7 529.2 — — Total 690.6 688.1 — — GSE mortgage-backed securities: Within 1 year — — 2.8 2.8 After 1 but within 5 years 95.4 97.7 766.4 778.9 After 5 but within 10 years 714.9 730.6 217.0 221.3 After 10 years 1,459.4 1,462.3 305.5 305.6 Total 2,269.7 2,290.6 1,291.7 1,308.6 State and municipal: Within 1 year — — 12.0 12.0 After 1 but within 5 years — — 213.1 221.5 After 5 but within 10 years — — 406.0 430.7 After 10 years — — 1,801.2 1,916.1 Total — — 2,432.3 2,580.3 Corporate: Within 1 year — — 5.0 5.0 After 5 but within 10 years — — 74.9 76.1 Total — — 79.9 81.1 Other: Within 1 year — — 1.5 1.5 Total — — 1.5 1.5 Total: Within 1 year 158.9 158.9 21.3 21.3 After 1 but within 5 years 627.1 626.9 979.5 1,000.4 After 5 but within 10 years 714.9 730.6 697.9 728.1 After 10 years 1,459.4 1,462.3 2,106.7 2,221.7 Total $ 2,960.3 $ 2,978.7 $ 3,805.4 $ 3,971.5 Management conducts a periodic review and evaluation of the securities portfolio to determine if the decline in fair value of any security is deemed to be other-than-temporary. Other-than-temporary impairment losses are recognized on debt securities when: (i) People’s United has an intention to sell the security; (ii) it is more likely than not that People’s United will be required to sell the security prior to recovery; or (iii) People’s United does not expect to recover the entire amortized cost basis of the security. Other-than-temporary impairment losses on debt securities are reflected in earnings as realized losses to the extent the impairment is related to credit losses of the issuer. The amount of the impairment related to other factors is recognized in other comprehensive income. Management has the ability and intent to hold the securities classified as held-to-maturity until they mature, at which time People’s United expects to receive full value for the securities. The following tables summarize those debt securities with unrealized losses, segregated by the length of time the securities have been in a continuous unrealized loss position, at the respective dates. Certain unrealized losses totaled less than $0.1 million. Continuous Unrealized Loss Position Less Than 12 Months 12 Months Or Longer Total As of September 30, 2019 (in millions) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Debt securities available-for-sale: GSE mortgage-backed securities $ 201.2 $ (0.4) $ 700.0 $ (3.1) $ 901.2 $ (3.5) U.S. Treasury and agency 105.3 (0.2) 463.1 (2.6) 568.4 (2.8) Total debt securities available-for-sale $ 306.5 $ (0.6) $ 1,163.1 $ (5.7) $ 1,469.6 $ (6.3) Debt securities held-to-maturity: GSE mortgage-backed securities $ 110.4 $ (0.1) $ 9.5 $ — $ 119.9 $ (0.1) State and municipal 15.6 (0.1) 12.0 (0.2) 27.6 (0.3) Corporate — — 8.4 (0.2) 8.4 (0.2) Total debt securities held-to-maturity $ 126.0 $ (0.2) $ 29.9 $ (0.4) $ 155.9 $ (0.6) Continuous Unrealized Loss Position Less Than 12 Months 12 Months Or Longer Total As of December 31, 2018 (in millions) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Debt securities available-for-sale: GSE mortgage-backed securities $ 132.4 $ (0.5) $ 1,656.3 $ (47.7) $ 1,788.7 $ (48.2) U.S. Treasury and agency — — 656.2 (21.1) 656.2 (21.1) Total debt securities available-for-sale $ 132.4 $ (0.5) $ 2,312.5 $ (68.8) $ 2,444.9 $ (69.3) Debt securities held-to-maturity: GSE mortgage-backed securities $ — $ — $ 1,334.3 $ (33.2) $ 1,334.3 $ (33.2) State and municipal 113.4 (0.7) 697.6 (17.7) 811.0 (18.4) Corporate 31.2 (0.6) 2.7 (0.1) 33.9 (0.7) Total debt securities held-to-maturity $ 144.6 $ (1.3) $ 2,034.6 $ (51.0) $ 2,179.2 $ (52.3) At September 30, 2019, approximately 6% of the 2,165 debt securities owned by the Company, consisting of 64 debt securities classified as available-for-sale and 69 debt securities classified as held-to-maturity, had gross unrealized losses totaling $6.3 million and $0.6 million, respectively. With respect to those securities with unrealized losses, all of the GSE mortgage-backed securities had AAA credit ratings and an average contractual maturity of 11 years. The state and municipal securities had an average credit rating of AA and a weighted average maturity of seven years. The cause of the gross unrealized losses with respect to all of the debt securities is directly related to changes in interest rates. At this time, management does not intend to sell such securities nor is it more likely than not, based upon available evidence, that management will be required to sell such securities prior to recovery. As such, management believes that all gross unrealized losses within the securities portfolio at September 30, 2019 represent temporary impairments. No other-than-temporary impairment losses were recognized in the Consolidated Statements of Income for the three and nine months ended September 30, 2019 or 2018. Security transactions are recorded on the trade date. Realized gains and losses are determined using the specific identification method and reported in non-interest income. Effective January 1, 2018, People’s United adopted new accounting guidance that requires equity investments (other than equity method investments) be measured at fair value with changes in fair value recognized in net income. At December 31, 2017, the Company’s securities portfolio included equity securities with an amortized cost of $9.6 million and a fair value of $8.7 million. Accordingly, upon adoption of this guidance, a cumulative-effect transition adjustment, representing the cumulative unrealized loss (net-of-tax) within accumulated other comprehensive income (loss) (“AOCL”), was recorded which served to decrease opening retained earnings by $0.6 million. People’s United recorded unrealized (losses) gains of $(0.5) million and $0.2 million for the three months ended September 30, 2019 and 2018, respectively, and $0.4 million and $1.0 million for the nine months ended September 30, 2019 and 2018, respectively (included in other non-interest income in the Consolidated Statements of Income) relating to the change in fair value of its equity securities during the respective periods. The Bank, as a member of the Federal Home Loan Bank (the “FHLB”) of Boston, is currently required to purchase and hold shares of capital stock in the FHLB of Boston (total cost of $129.7 million and $124.2 million at September 30, 2019 and December 31, 2018, respectively) in an amount equal to its membership base investment plus an activity based investment determined according to the Bank’s level of outstanding FHLB advances. As a result of prior acquisitions, the Bank acquired shares of capital stock in the FHLB of New York (total cost of $0.7 million at both September 30, 2019 and December 31, 2018, respectively). Based on the current capital adequacy and liquidity position of both the FHLB of Boston and the FHLB of New York, management believes there is no impairment in the Company’s investment at September 30, 2019 and the cost of the investment approximates fair value. The Bank, as a member of the Federal Reserve Bank system, is currently required to purchase and hold shares of capital stock in the FRB-NY (total cost of $203.6 million and $178.5 million at September 30, 2019 and December 31, 2018, respectively) in an amount equal to 6% of its capital and surplus. Based on the current capital adequacy and liquidity position of the FRB-NY, management believes there is no impairment in the Company’s investment at September 30, 2019 and the cost of the investment approximates fair value.

Loans

Loans	9 Months Ended
Loans	Sep. 30, 2019
Receivables [Abstract]
Loans	NOTE 4. LOANS For purposes of disclosures related to the credit quality of financing receivables and the allowance for loan losses, People’s United has identified two loan portfolio segments, Commercial and Retail, which are comprised of the following loan classes: • Commercial Portfolio : commercial real estate; commercial and industrial; and equipment financing. • Retail Portfolio : residential mortgage; home equity; and other consumer. Loans acquired in connection with business combinations are referred to as ‘acquired’ loans as a result of the manner in which they are accounted for (see further discussion under ‘Acquired Loans’). All other loans are referred to as ‘originated’ loans. Accordingly, selected credit quality disclosures that follow are presented separately for the ‘originated’ loan portfolio and the ‘acquired’ loan portfolio. People’s United maintains several significant accounting policies with respect to loans, including: • Establishment of the allowance for loan losses (including the identification of ‘impaired’ loans and related impairment measurement considerations); • Income recognition (including the classification of a loan as ‘non-accrual’ and the treatment of loan origination costs); and • Recognition of loan charge-offs. The Company did not change its application of the accounting policies noted above or its methodology for determining the allowance for loan losses during the nine months ended September 30, 2019. The following table summarizes People’s United’s loans by loan portfolio segment and class: September 30, 2019 December 31, 2018 (in millions) Originated Acquired Total Originated Acquired Total Commercial: Commercial real estate $ 9,721.4 $ 2,465.5 $ 12,186.9 $ 9,798.5 $ 1,851.1 $ 11,649.6 Commercial and industrial 9,720.1 825.8 10,545.9 8,292.3 796.6 9,088.9 Equipment financing 4,484.5 251.1 4,735.6 3,937.7 401.5 4,339.2 Total Commercial Portfolio 23,926.0 3,542.4 27,468.4 22,028.5 3,049.2 25,077.7 Retail: Residential mortgage: Adjustable-rate 5,547.9 1,368.5 6,916.4 5,854.1 807.9 6,662.0 Fixed-rate 1,113.8 1,278.5 2,392.3 935.1 557.1 1,492.2 Total residential mortgage 6,661.7 2,647.0 9,308.7 6,789.2 1,365.0 8,154.2 Home equity and other consumer: Home equity 1,685.7 271.2 1,956.9 1,789.5 173.0 1,962.5 Other consumer 39.3 8.1 47.4 42.8 4.2 47.0 Total home equity and other consumer 1,725.0 279.3 2,004.3 1,832.3 177.2 2,009.5 Total Retail Portfolio 8,386.7 2,926.3 11,313.0 8,621.5 1,542.2 10,163.7 Total loans $ 32,312.7 $ 6,468.7 $ 38,781.4 $ 30,650.0 $ 4,591.4 $ 35,241.4 Loan origination fees and certain direct loan origination costs are deferred, and the net fee or cost is recognized in interest income as an adjustment of yield. Depending on the loan portfolio, amounts are amortized or accreted using the level yield method over either the actual life or the estimated average life of the loan. Net deferred loan costs, which are included in loans by respective class and accounted for as interest yield adjustments, totaled $88.2 million at September 30, 2019 and $94.6 million at December 31, 2018. The following tables present a summary, by loan portfolio segment, of activity in the allowance for loan losses for the three and nine months ended September 30, 2019 and 2018. With respect to the originated portfolio, an allocation of a portion of the allowance to one segment does not preclude its availability to absorb losses in another segment. Three months ended Commercial Retail September 30, 2019 (in millions) Originated Acquired Total Originated Acquired Total Total Balance at beginning of period $ 210.9 $ 3.7 $ 214.6 $ 29.2 $ 0.2 $ 29.4 $ 244.0 Charge-offs (6.1) (1.4) (7.5) (0.7) — (0.7) (8.2) Recoveries 1.6 0.3 1.9 0.5 — 0.5 2.4 Net loan charge-offs (4.5) (1.1) (5.6) (0.2) — (0.2) (5.8) Provision for loan losses 6.9 0.9 7.8 — — — 7.8 Balance at end of period $ 213.3 $ 3.5 $ 216.8 $ 29.0 $ 0.2 $ 29.2 $ 246.0 Nine months ended Commercial Retail September 30, 2019 (in millions) Originated Acquired Total Originated Acquired Total Total Balance at beginning of period $ 205.6 $ 3.9 $ 209.5 $ 30.7 $ 0.2 $ 30.9 $ 240.4 Charge-offs (13.9) (6.2) (20.1) (2.9) — (2.9) (23.0) Recoveries 4.2 1.1 5.3 2.3 — 2.3 7.6 Net loan charge-offs (9.7) (5.1) (14.8) (0.6) — (0.6) (15.4) Provision for loan losses 17.4 4.7 22.1 (1.1) — (1.1) 21.0 Balance at end of period $ 213.3 $ 3.5 $ 216.8 $ 29.0 $ 0.2 $ 29.2 $ 246.0 Three months ended Commercial Retail September 30, 2018 (in millions) Originated Acquired Total Originated Acquired Total Total Balance at beginning of period $ 202.0 $ 3.8 $ 205.8 $ 30.8 $ 0.2 $ 31.0 $ 236.8 Charge-offs (5.7) (2.0) (7.7) (0.7) — (0.7) (8.4) Recoveries 0.6 0.4 1.0 0.4 — 0.4 1.4 Net loan charge-offs (5.1) (1.6) (6.7) (0.3) — (0.3) (7.0) Provision for loan losses 6.3 1.7 8.0 0.2 — 0.2 8.2 Balance at end of period $ 203.2 $ 3.9 $ 207.1 $ 30.7 $ 0.2 $ 30.9 $ 238.0 Nine months ended Commercial Retail September 30, 2018 (in millions) Originated Acquired Total Originated Acquired Total Total Balance at beginning of period $ 201.1 $ 3.4 $ 204.5 $ 29.7 $ 0.2 $ 29.9 $ 234.4 Charge-offs (12.9) (6.3) (19.2) (2.6) — (2.6) (21.8) Recoveries 2.6 1.0 3.6 1.7 — 1.7 5.3 Net loan charge-offs (10.3) (5.3) (15.6) (0.9) — (0.9) (16.5) Provision for loan losses 12.4 5.8 18.2 1.9 — 1.9 20.1 Balance at end of period $ 203.2 $ 3.9 $ 207.1 $ 30.7 $ 0.2 $ 30.9 $ 238.0 The following tables summarize, by loan portfolio segment and impairment methodology, the allowance for loan losses and related portfolio balances: Commercial Retail Total As of September 30, 2019 (in millions) Portfolio Allowance Portfolio Allowance Portfolio Allowance Originated loans: Collectively evaluated for impairment $ 22,258.6 $ 206.0 $ 9,850.9 $ 26.9 $ 32,109.5 $ 232.9 Individually evaluated for impairment 112.7 7.3 90.6 2.1 203.3 9.4 Acquired loans: PCI (1) 219.0 2.2 72.2 0.2 291.2 2.4 Purchased performing: Collectively evaluated for impairment 4,870.5 1.3 1,292.4 — 6,162.9 1.3 Individually evaluated for impairment 7.6 — 6.9 — 14.5 — Total $ 27,468.4 $ 216.8 $ 11,313.0 $ 29.2 $ 38,781.4 $ 246.0 Commercial Retail Total As of December 31, 2018 (in millions) Portfolio Allowance Portfolio Allowance Portfolio Allowance Originated loans: Collectively evaluated for impairment $ 21,900.1 $ 198.9 $ 8,535.0 $ 28.4 $ 30,435.1 $ 227.3 Individually evaluated for impairment 128.4 6.7 86.5 2.3 214.9 9.0 Acquired loans: PCI (1) 300.3 2.2 99.6 0.1 399.9 2.3 Purchased performing: Collectively evaluated for impairment 2,744.4 1.7 1,439.1 — 4,183.5 1.7 Individually evaluated for impairment 4.5 — 3.5 0.1 8.0 0.1 Total $ 25,077.7 $ 209.5 $ 10,163.7 $ 30.9 $ 35,241.4 $ 240.4 1. Purchased credit impaired (“PCI”) loans are evaluated for impairment on a pool basis. The recorded investments, by class of loan, in originated non-performing loans are summarized as follows: September 30, December 31, (in millions) Commercial: Commercial real estate $ 25.1 $ 33.5 Commercial and industrial 37.7 38.0 Equipment financing 41.5 42.0 Total (1) 104.3 113.5 Retail: Residential mortgage 36.6 38.9 Home equity 14.3 15.3 Other consumer 0.1 — Total (2) 51.0 54.2 Total $ 155.3 $ 167.7 1. Reported net of government guarantees totaling $1.4 million and $1.9 million at September 30, 2019 and December 31, 2018, respectively. These government guarantees relate, almost entirely, to guarantees provided by the Small Business Administration as well as selected other Federal agencies and represent the carrying value of the loans that are covered by such guarantees, the extent of which (i.e. full or partial) varies by loan. At September 30, 2019, the principal loan classes to which these government guarantees relate are commercial and industrial loans (95%) and commercial real estate loans (5%). 2. Includes $22.1 million and $24.8 million of loans in the process of foreclosure at September 30, 2019 and December 31, 2018, respectively. The preceding table excludes acquired loans that are (i) accounted for as PCI loans and/or (ii) covered by a Federal Deposit Insurance Corporation (“FDIC”) loss-share agreement (“LSA”), which totaled $10.1 million and $44.1 million at September 30, 2019 and December 31, 2018, respectively. Such loans otherwise meet People’s United’s definition of a non-performing loan but are excluded because the loans are included in loan pools that are considered performing and/or credit losses are covered by an FDIC LSA. The discounts arising from recording these loans at fair value were due, in part, to credit quality. Accordingly, such loans are generally accounted for on a pool basis and the accretable yield on the pools is being recognized as interest income over the life of the loans based on expected cash flows at the pool level. In addition, the table excludes purchased performing loans totaling $11.0 million and $6.0 million at September 30, 2019 and December 31, 2018, respectively, all of which became non-performing subsequent to acquisition. A loan is generally considered “non-performing” when it is placed on non-accrual status. A loan is generally placed on non-accrual status when it becomes 90 days past due as to interest or principal payments. Past due status is based on the contractual payment terms of the loan. A loan may be placed on non-accrual status before it reaches 90 days past due if such loan has been identified as presenting uncertainty with respect to the collectability of interest and principal. A loan past due 90 days or more may remain on accruing status if such loan is both well secured and in the process of collection. All previously accrued but unpaid interest on non-accrual loans is reversed from interest income in the period in which the accrual of interest is discontinued. Interest payments received on non-accrual loans (including impaired loans) are generally applied as a reduction of principal if future collections are doubtful, although such interest payments may be recognized as income. A loan remains on non-accrual status until the factors that indicated doubtful collectability no longer exist or until a loan is determined to be uncollectible and is charged off against the allowance for loan losses. There were no loans past due 90 days or more and still accruing interest at September 30, 2019 or December 31, 2018. A loan is considered impaired when, based on current information and events, it is probable that the Company will be unable to collect all amounts due in accordance with the original contractual terms of the loan agreement, including scheduled principal and interest payments. Impaired loans also include certain loans whose terms have been modified in such a way that they are considered troubled debt restructurings (“TDRs”). Loans are considered TDRs if the borrower is experiencing financial difficulty and is afforded a concession by People’s United, such as, but not limited to: (i) payment deferral; (ii) a reduction of the stated interest rate for the remaining contractual life of the loan; (iii) an extension of the loan’s original contractual term at a stated interest rate lower than the current market rate for a new loan with similar risk; (iv) capitalization of interest; or (v) forgiveness of principal or interest. TDRs may either be accruing or placed on non-accrual status (and reported as non-performing loans) depending upon the loan’s specific circumstances, including the nature and extent of the related modifications. TDRs on non-accrual status remain classified as such until the loan qualifies for return to accrual status. Loans qualify for return to accrual status once they have demonstrated performance with the restructured terms of the loan agreement for a minimum of six months in the case of a commercial loan or, in the case of a retail loan, when the loan is less than 90 days past due. Loans may continue to be reported as TDRs after they are returned to accrual status. In accordance with regulatory guidance, residential mortgage and home equity loans restructured in connection with the borrower’s bankruptcy and meeting certain criteria are also required to be classified as TDRs, included in non-performing loans and written down to the estimated collateral value, regardless of delinquency status. Acquired loans that are modified are not considered for TDR classification provided they are evaluated for impairment on a pool basis (see further discussion under ‘Acquired Loans’). Impairment is evaluated on a collective basis for smaller-balance loans with similar credit risk and on an individual loan basis for other loans. If a loan is deemed to be impaired, a specific valuation allowance is allocated, if necessary, so that the loan is reported (net of the allowance) at the present value of expected future cash flows discounted at the loan’s original effective interest rate or at the fair value of the collateral less cost to sell if repayment is expected solely from the collateral. Interest payments on impaired non-accrual loans are typically applied to principal unless collectability of the principal amount is reasonably assured, in which case interest is recognized on a cash basis. Impaired loans, or portions thereof, are charged off when deemed uncollectible. At September 30, 2019 and December 31, 2018, People’s United’s recorded investment in loans classified as TDRs totaled $180.6 million and $179.4 million, respectively. The related allowance for loan losses was $3.6 million at September 30, 2019 and $4.5 million at December 31, 2018. Interest income recognized on TDRs totaled $1.5 million and $1.2 million for the three months ended September 30, 2019 and 2018, respectively, and $4.3 million and $4.0 million for the nine months ended September 30, 2019 and 2018, respectively. Fundings under commitments to lend additional amounts to borrowers with loans classified as TDRs were immaterial for the three and nine months ended September 30, 2019 and 2018. Loans that were modified and classified as TDRs during the three and nine months ended September 30, 2019 and 2018 principally involve reduced payment and/or payment deferral, extension of term (generally no more than two years for commercial loans and five years for retail loans) and/or a temporary reduction of interest rate (generally less than 200 basis points). The following tables summarize, by class of loan, the recorded investments in loans modified as TDRs during the three and nine months ended September 30, 2019 and 2018. For purposes of this disclosure, recorded investments represent amounts immediately prior to and subsequent to the restructuring. Three Months Ended September 30, 2019 (dollars in millions) Number of Contracts Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Commercial: Commercial real estate (1) 7 $ 13.1 $ 13.1 Commercial and industrial (2) 8 4.1 4.1 Equipment financing (3) 10 9.5 9.5 Total 25 26.7 26.7 Retail: Residential mortgage (4) 15 6.5 6.5 Home equity (5) 15 1.3 1.3 Other consumer — — — Total 30 7.8 7.8 Total 55 $ 34.5 $ 34.5 1. Represents the following concessions: extension of term (5 contracts; recorded investment of $1.7 million); or a combination of concessions (2 contracts; recorded investment of $11.4 million). 2. Represents the following concessions: extension of term (5 contracts; recorded investment of $1.9 million); reduced payment and/or payment deferral (2 contracts; recorded investment of $0.3 million); or a combination of concessions (1 contract; recorded investment of $1.9 million). 3. Represents the following concessions: extension of term (1 contract; recorded investment of $0.4 million); reduced payment and/or payment deferral (5 contracts; recorded investment of $5.1 million); or a combination of concessions (4 contracts; recorded investment of $4.0 million). 4. Represents the following concessions: loans restructured through bankruptcy (4 contracts; recorded investment of $1.6 million); reduced payment and/or payment deferral (9 contracts; recorded investment of $3.7 million); or a combination of concessions (2 contracts; recorded investment of $1.2 million). 5. Represents the following concessions: loans restructured through bankruptcy (6 contracts; recorded investment of $0.4 million); reduced payment and/or payment deferral (5 contracts; recorded investment of $0.6 million); or a combination of concessions (4 contracts; recorded investment of $0.3 million). Nine Months Ended September 30, 2019 (dollars in millions) Number Pre-Modification Post-Modification Commercial: Commercial real estate (1) 8 $ 13.7 $ 13.7 Commercial and industrial (2) 27 27.5 27.5 Equipment financing (3) 33 22.9 22.9 Total 68 64.1 64.1 Retail: Residential mortgage (4) 73 22.2 22.2 Home equity (5) 83 7.0 7.0 Other consumer — — — Total 156 29.2 29.2 Total 224 $ 93.3 $ 93.3 1. Represents the following concessions: extension of term (5 contracts; recorded investment of $1.7 million); reduced payment and/or payment deferral (1 contract; recorded investment of $0.6 million); or a combination of concessions (2 contracts; recorded investment of $11.4 million). 2. Represents the following concessions: extension of term (22 contracts; recorded investment of $24.3 million); reduced payment and/or payment deferral (2 contracts; recorded investment of $0.3 million); or a combination of concessions (3 contracts; recorded investment of $2.9 million). 3. Represents the following concessions: extension of term (5 contracts; recorded investment of $1.6 million); reduced payment and/or payment deferral (22 contracts; recorded investment of $16.9 million); or a combination of concessions (6 contracts; recorded investment of $4.4 million). 4. Represents the following concessions: loans restructured through bankruptcy (39 contracts; recorded investment of $8.2 million); reduced payment and/or payment deferral (21 contracts; recorded investment of $8.4 million); or a combination of concessions (13 contracts; recorded investment of $5.6 million). 5. Represents the following concessions: loans restructured through bankruptcy (48 contracts; recorded investment of $2.6 million); reduced payment and/or payment deferral (16 contracts; recorded investment of $2.8 million); or a combination of concessions (19 contracts; recorded investment of $1.6 million). Three Months Ended September 30, 2018 (dollars in millions) Number of Contracts Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Commercial: Commercial real estate (1) 4 $ 20.7 $ 20.7 Commercial and industrial (2) 10 10.3 10.3 Equipment financing (3) 5 10.3 10.3 Total 19 41.3 41.3 Retail: Residential mortgage (4) 4 1.4 1.4 Home equity (5) 19 2.2 2.2 Other consumer — — — Total 23 3.6 3.6 Total 42 $ 44.9 $ 44.9 1. Represents the following concession: extension of term (3 contracts; recorded investment of $20.2 million); or reduced payment and/or payment deferral (1 contract; recorded investment of $0.5 million). 2. Represents the following concessions: extension of term (6 contracts; recorded investment of $3.6 million); reduced payment and/or payment deferral (2 contracts; recorded investment of $6.4 million); or a combination of concessions (2 contracts; recorded investment of $0.3 million). 3. Represents the following concessions: extension of term (2 contracts; recorded investment of $3.3 million); reduced payment and/or payment deferral (2 contracts; recorded investment of $5.9 million); a combination of concessions (1 contract; recorded investment of $1.1 million). 4. Represents the following concessions: loans restructured through bankruptcy (2 contracts; recorded investment of $0.6 million); reduced payment and/or payment deferral (1 contract; recorded investment of $0.7 million); or a combination of concessions (1 contract; recorded investment of $0.1 million). 5. Represents the following concessions: loans restructured through bankruptcy (11 contracts; recorded investment of $1.1 million); reduced payment and/or payment deferral (6 contracts; recorded investment of $1.0 million); or a combination of concessions (2 contracts; recorded investment of $0.1 million). Nine Months Ended September 30, 2018 (dollars in millions) Number Pre-Modification Post-Modification Commercial: Commercial real estate (1) 9 $ 24.3 $ 24.3 Commercial and industrial (2) 34 55.2 55.2 Equipment financing (3) 16 20.4 20.4 Total 59 99.9 99.9 Retail: Residential mortgage (4) 16 4.9 4.9 Home equity (5) 56 4.9 4.9 Other consumer — — — Total 72 9.8 9.8 Total 131 $ 109.7 $ 109.7 1. Represents the following concessions: extension of term (8 contracts; recorded investment of $23.8 million); or reduced payment and/or payment deferral (1 contract; recorded investment of $0.5 million). 2. Represents the following concessions: extension of term (21 contracts; recorded investment of $30.7 million); reduced payment and/or payment deferral (10 contracts; recorded investment of $23.8 million); or a combination of concessions (3 contracts; recorded investment of $0.7 million). 3. Represents the following concessions: extension of term (2 contracts; recorded investment of $3.3 million): reduced payment and/or payment deferral (8 contracts; recorded investment of $12.9 million); or a combination of concessions (6 contracts; recorded investment of $4.2 million). 4. Represents the following concessions: loans restructured through bankruptcy (5 contracts; recorded investment of $0.9 million); reduced payment and/or payment deferral (6 contracts; recorded investment of $2.4 million); or a combination of concessions (5 contracts; recorded investment of $1.6 million). 5. Represents the following concessions: loans restructured through bankruptcy (37 contracts; recorded investment of $2.8 million); reduced payment and/or payment deferral (10 contracts; recorded investment of $1.3 million); or a combination of concessions (9 contracts; recorded investment of $0.8 million). The following is a summary, by class of loan, of information related to TDRs completed within the previous 12 months that subsequently defaulted during the three and nine months ended September 30, 2019 and 2018. For purposes of this disclosure, the previous 12 months is measured from October 1 of the respective prior year and a default represents a previously-modified loan that became past due 30 days or more during the three or nine months ended September 30, 2019 or 2018. Three Months Ended September 30, 2019 2018 (dollars in millions) Number of Contracts Recorded Investment as of Period End Number of Contracts Recorded Investment as of Period End Commercial: Commercial real estate 1 $ 0.2 — $ — Commercial and industrial — — 4 5.0 Equipment financing 1 0.3 1 0.2 Total 2 0.5 5 5.2 Retail: Residential mortgage 2 0.6 5 0.9 Home equity 3 0.1 8 0.6 Other consumer — — — — Total 5 0.7 13 1.5 Total 7 $ 1.2 18 $ 6.7 Nine Months Ended September 30, 2019 2018 (dollars in millions) Number Recorded Number Recorded Commercial: Commercial real estate 1 $ 0.2 2 $ 0.8 Commercial and industrial — — 13 8.5 Equipment financing 8 8.2 7 6.8 Total 9 8.4 22 16.1 Retail: Residential mortgage 6 2.4 7 1.3 Home equity 9 0.6 9 0.6 Other consumer — — — — Total 15 3.0 16 1.9 Total 24 $ 11.4 38 $ 18.0 People’s United’s impaired loans consist of certain loans that have been placed on non-accrual status, including all TDRs. The following table summarizes, by class of loan, information related to individually-evaluated impaired loans. As of September 30, 2019 As of December 31, 2018 (in millions) Unpaid Principal Balance Recorded Investment Related Allowance for Loan Losses Unpaid Principal Balance Recorded Investment Related Allowance for Loan Losses Without a related allowance for loan losses: Commercial: Commercial real estate $ 38.9 $ 35.7 $ — $ 31.0 $ 28.1 $ — Commercial and industrial 34.9 29.9 — 45.6 42.0 — Equipment financing 21.2 19.2 — 20.2 18.0 — Retail: Residential mortgage 69.1 61.4 — 66.8 59.3 — Home equity 26.5 23.2 — 23.8 20.3 — Other consumer — — — — — — Total $ 190.6 $ 169.4 $ — $ 187.4 $ 167.7 $ — With a related allowance for loan losses: Commercial: Commercial real estate $ 2.6 $ 2.3 $ 0.1 $ 23.8 $ 21.8 $ 1.6 Commercial and industrial 22.4 18.9 5.6 12.6 10.2 2.4 Equipment financing 14.6 14.3 1.6 16.2 12.8 2.7 Retail: Residential mortgage 11.5 11.5 1.5 8.8 8.8 1.7 Home equity 1.4 1.4 0.6 1.7 1.6 0.7 Other consumer — — — — — — Total $ 52.5 $ 48.4 $ 9.4 $ 63.1 $ 55.2 $ 9.1 Total impaired loans: Commercial: Commercial real estate $ 41.5 $ 38.0 $ 0.1 $ 54.8 $ 49.9 $ 1.6 Commercial and industrial 57.3 48.8 5.6 58.2 52.2 2.4 Equipment financing 35.8 33.5 1.6 36.4 30.8 2.7 Total 134.6 120.3 7.3 149.4 132.9 6.7 Retail: Residential mortgage 80.6 72.9 1.5 75.6 68.1 1.7 Home equity 27.9 24.6 0.6 25.5 21.9 0.7 Other consumer — — — — — — Total 108.5 97.5 2.1 101.1 90.0 2.4 Total $ 243.1 $ 217.8 $ 9.4 $ 250.5 $ 222.9 $ 9.1 The following tables summarize, by class of loan, the average recorded investment and interest income recognized on impaired loans for the periods indicated. The average recorded investment amounts are based on month-end balances. Three Months Ended September 30, 2019 2018 (in millions) Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Commercial: Commercial real estate $ 28.8 $ 0.4 $ 36.2 $ 0.4 Commercial and industrial 47.6 0.3 52.4 0.2 Equipment financing 28.5 0.1 36.0 0.1 Total 104.9 0.8 124.6 0.7 Retail: Residential mortgage 70.5 0.6 68.6 0.4 Home equity 23.9 0.2 20.7 0.2 Other consumer — — — — Total 94.4 0.8 89.3 0.6 Total $ 199.3 $ 1.6 $ 213.9 $ 1.3 Nine Months Ended September 30, 2019 2018 (in millions) Average Interest Average Interest Commercial: Commercial real estate $ 39.9 $ 0.8 $ 40.7 $ 0.9 Commercial and industrial 44.3 1.4 50.6 1.3 Equipment financing 25.5 0.2 39.8 0.2 Total 109.7 2.4 131.1 2.4 Retail: Residential mortgage 67.2 1.6 69.5 1.3 Home equity 22.7 0.5 21.0 0.4 Other consumer — — — — Total 89.9 2.1 90.5 1.7 Total $ 199.6 $ 4.5 $ 221.6 $ 4.1 The following tables summarize, by class of loan, aging information for originated loans: Past Due As of September 30, 2019 (in millions) Current 30-89 Days 90 Days or More Total Total Originated Commercial: Commercial real estate $ 9,695.6 $ 5.2 $ 20.6 $ 25.8 $ 9,721.4 Commercial and industrial 9,696.4 9.1 14.6 23.7 9,720.1 Equipment financing 4,389.0 84.2 11.3 95.5 4,484.5 Total 23,781.0 98.5 46.5 145.0 23,926.0 Retail: Residential mortgage 6,614.2 25.2 22.3 47.5 6,661.7 Home equity 1,673.2 6.3 6.2 12.5 1,685.7 Other consumer 39.0 0.2 0.1 0.3 39.3 Total 8,326.4 31.7 28.6 60.3 8,386.7 Total originated loans $ 32,107.4 $ 130.2 $ 75.1 $ 205.3 $ 32,312.7 Included in the “Current” and “30-89 Days” categories above are early non-performing commercial real estate loans, commercial and industrial loans, and equipment financing loans totaling $4.6 million, $24.4 million and $30.2 million, respectively, and $22.4 million of retail loans in the process of foreclosure or bankruptcy. These loans are less than 90 days past due but have been placed on non-accrual status as a result of having been identified as presenting uncertainty with respect to the collectability of interest and principal. Past Due As of December 31, 2018 (in millions) Current 30-89 Days 90 Days or More Total Total Originated Commercial: Commercial real estate $ 9,762.1 $ 23.0 $ 13.4 $ 36.4 $ 9,798.5 Commercial and industrial 8,261.5 6.9 23.9 30.8 8,292.3 Equipment financing 3,855.3 68.8 13.6 82.4 3,937.7 Total 21,878.9 98.7 50.9 149.6 22,028.5 Retail: Residential mortgage 6,723.2 38.6 27.4 66.0 6,789.2 Home equity 1,776.0 5.8 7.7 13.5 1,789.5 Other consumer 42.7 0.1 — 0.1 42.8 Total 8,541.9 44.5 35.1 79.6 8,621.5 Total originated loans $ 30,420.8 $ 143.2 $ 86.0 $ 229.2 $ 30,650.0 Included in the “Current” and “30-89 Days” categories above are early non-performing commercial real estate loans, commercial and industrial loans, and equipment financing loans totaling $20.3 million, $15.8 million and $28.4 million, respectively, and $19.1 million of retail loans in the process of foreclosure or bankruptcy. These loans are less than 90 days past due but have been placed on non-accrual status as a result of having been identified as presenting uncertainty with respect to the collectability of interest and principal. Commercial Credit Quality Indicators The Company utilizes an internal loan risk rating system as a means of monitoring portfolio credit quality and identifying both problem and potential problem loans. Under the Company’s risk rating system, loans not meeting the criteria for problem and potential problem loans as specified below are considered to be “Pass”-rated loans. Problem and potential problem loans are classified as either “Special Mention,” “Substandard” or “Doubtful.” Loans that do not currently expose the Company to sufficient enough risk of loss to warrant classification as either Substandard or Doubtful, but possess weaknesses that deserve management’s close attention, are classified as Special Mention. Substandard loans represent those credits characterized by the distinct possibility that the Company will sustain some loss if the deficiencies are not corrected. Loans classified as Doubtful possess all the weaknesses inherent in those classified Substandard with the added characteristic that collection or liquidation in full, on the basis of existing facts, conditions and values, is highly questionable and/or improbable. Risk ratings on commercial loans are subject to ongoing monitoring by lending and credit personnel with such ratings updated annually or more frequently, if warranted. The Company’s internal Loan Review function is responsible for independently evaluating the appropriateness of those credit risk ratings in connection with its cyclical reviews, the approach to which is risk-based and determined by reference to underlying portfolio credit quality and the results of prior reviews. Differences in risk ratings noted in conjunction with such periodic portfolio loan reviews, if any, are reported to management each month. Retail Credit Quality Indicators Pools of smaller-balance, homogeneous loans with similar risk and loss characteristics are also assessed for probable losses. These loan pools include residential mortgage, home equity and other consumer loans that are not assigned individual loan risk ratings. Rather, the assessment of these portfolios is based upon a consideration of recent historical loss experience, broader portfolio indicators, including trends in delinquencies, non-performing loans and portfolio concentrations, and portfolio-specific risk characteristics, the combination of which determines whether a loan is classified as “High”, “Moderate” or “Low” risk. The portfolio-specific risk characteristics considered include: (i) collateral values/loan-to-value (“LTV”) ratios (above and below 70%); (ii) borrower credit scores under the FICO scoring system (above and below a score of 680); and (iii) other relevant portfolio risk elements such as income verification at the time of underwriting (stated income vs. non-stated income) and the property’s intended use (owner-occupied, non-owner occupied, second home, etc.). In classifying a loan as either “High”, “Moderate” or “Low” risk, the combination of each of the aforementioned risk characteristics is considered for that loan, resulting, effectively, in a “matrix approach” to its risk classification. These risk classifications are reviewed quarterly to ensure that they continue to be appropriate in light of changes within the portfolio and/or economic indicators as well as other industry developments. For example, to the extent LTV ratios exceed 70% (reflecting a weaker collateral position for the Company) or borrower FICO scores are less than 680 (reflecting weaker financial standing and/or credit history of the customer), the loans are considered to have an increased level of inherent loss. As a result, a loan with a combination of these characteristics would generally be classified as “High” risk. Conversely, as LTV ratios decline (reflecting a stronger collateral position for the Company) or borrower FICO scores exceed 680 (reflecting stronger financial standing and/or credit history of the customer), the loans are considered to have a decreased level of inherent loss. A loan with a combination of these characteristics would generally be classified as “Low” risk. This analysis also considers (i) the extent of underwriting that occurred at the time of origination (direct income verification provides further support for credit decisions) and (ii) the property’s intended use (owner-occupied properties are less likely to default compared to ‘i

Stockholders' Equity

Stockholders' Equity	9 Months Ended
Stockholders' Equity	Sep. 30, 2019
Equity [Abstract]
Stockholders' Equity	NOTE 5. STOCKHOLDERS' EQUITY Preferred Stock and Common Stock People’s United is authorized to issue (i) 50.0 million shares of preferred stock, par value of $0.01 per share, of which 10.0 million shares were outstanding at both September 30, 2019 and December 31, 2018, and (ii) 1.95 billion shares of common stock, par value of $0.01 per share, of which 487.6 million shares and 466.3 million shares were issued at September 30, 2019 and December 31, 2018, respectively. Treasury Stock Treasury stock includes (i) common stock repurchased by People’s United, either directly or through agents, in the open market at prices and terms satisfactory to management in connection with stock repurchases authorized by its Board of Directors (86.4 million shares at both September 30, 2019 and December 31, 2018) and (ii) common stock purchased in the open market by a trustee with funds provided by People’s United and originally intended for awards under the People’s United Financial, Inc. 2007 Recognition and Retention Plan (the “RRP”) (2.6 million shares at both September 30, 2019 and December 31, 2018). Following shareholder approval of the People’s United Financial, Inc. 2014 Long-Term Incentive Plan in 2014, no new awards may be granted under the RRP. In June 2019, the Company’s Board of Directors authorized the repurchase of up to 20.0 million shares of People’s United’s common stock. Such shares may be repurchased, either directly or through agents, in the open market at prices and terms satisfactory to management. To date, no shares have been repurchased. Comprehensive Income Comprehensive income represents the sum of net income and items of “other comprehensive income or loss,” including (on an after-tax basis): (i) net actuarial gains and losses, prior service credits and costs, and transition assets and obligations related to People’s United’s pension and other postretirement plans; (ii) net unrealized gains and losses on debt securities available-for-sale; (iii) net unrealized gains and losses on debt securities transferred to held-to-maturity; and (iv) net unrealized gains and losses on derivatives accounted for as cash flow hedges. People’s United’s total comprehensive income for the three and nine months ended September 30, 2019 and 2018 is reported in the Consolidated Statements of Comprehensive Income. The following is a summary of the changes in the components of AOCL, which are included in People’s United’s stockholders’ equity on an after-tax basis: (in millions) Pension and Other Postretirement Plans Net Unrealized Gains (Losses) on Debt Securities Available-for-Sale Net Unrealized Gains (Losses) on Debt Securities Transferred to Held-to-Maturity Net Unrealized Gains (Losses) on Derivatives Accounted for as Cash Flow Hedges Total AOCL Balance at December 31, 2018 $ (192.5) $ (47.0) $ (15.3) $ (2.0) $ (256.8) Other comprehensive income — 66.2 — 1.6 67.8 Amounts reclassified from AOCL (1) 3.9 — 2.0 0.8 6.7 Current period other comprehensive 3.9 66.2 2.0 2.4 74.5 Balance at September 30, 2019 $ (188.6) $ 19.2 $ (13.3) $ 0.4 $ (182.3) (in millions) Pension and Other Postretirement Plans Net Unrealized Gains (Losses) on Debt Securities Available-for-Sale Net Unrealized Gains (Losses) on Debt Securities Transferred to Held-to-Maturity Net Unrealized Gains (Losses) on Derivatives Accounted for as Cash Flow Hedges Total AOCL Balance at December 31, 2017 $ (144.1) $ (21.6) $ (15.1) $ (0.9) $ (181.7) Other comprehensive income — (56.2) — (2.4) (58.6) Amounts reclassified from AOCL (1) 4.5 (0.1) 2.3 0.1 6.8 Current period other comprehensive 4.5 (56.3) 2.3 (2.3) (51.8) Transition adjustments related to (30.0) (3.9) (3.2) (0.2) (37.3) Balance at September 30, 2018 $ (169.6) $ (81.8) $ (16.0) $ (3.4) $ (270.8) 1. See the following table for details about these reclassifications. 2. See Notes 3 and 15. The following is a summary of the amounts reclassified from AOCL: Amounts Reclassified from AOCL Affected Line Item in the Statement Where Net Income is Presented Three Months Ended Nine Months Ended (in millions) 2019 2018 2019 2018 Details about components of AOCL: Amortization of pension and other postretirement plans items: Net actuarial loss $ (1.4) $ (2.0) $ (4.1) $ (6.2) (1) Prior service credit — — — 0.2 (1) (1.4) (2.0) (4.1) (6.0) Income before income tax expense 0.4 0.5 0.2 1.5 Income tax expense (1.0) (1.5) (3.9) (4.5) Net income Reclassification adjustment for net realized gains (losses) on debt securities available-for-sale — — — 0.1 Income before income tax expense (2) — — — — Income tax expense — — — 0.1 Net income Amortization of unrealized losses on debt securities transferred to held-to-maturity (1.1) (0.9) (2.7) (3.0) Income before income tax expense (3) 0.3 0.2 0.7 0.7 Income tax expense (0.8) (0.7) (2.0) (2.3) Net income Amortization of unrealized gains and losses on cash flow hedges: Interest rate swaps (0.3) (0.3) (1.1) (0.3) (4) Interest rate locks 0.1 0.1 0.1 0.1 (4) (0.2) (0.2) (1.0) (0.2) Income before income tax expense — 0.1 0.2 0.1 Income tax expense (0.2) (0.1) (0.8) (0.1) Net income Total reclassifications for the period $ (2.0) $ (2.3) $ (6.7) $ (6.8) 1. Included in the computation of net periodic benefit income (expense) reflected in other non-interest expense (see Note 8 for additional details). 2. Included in other non-interest income. 3. Included in interest and dividend income - securities. 4. Included in interest expense - notes and debentures.

Earnings Per Common Share

Earnings Per Common Share	9 Months Ended
Earnings Per Common Share	Sep. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Common Share	NOTE 6. EARNINGS PER COMMON SHARE The following is an analysis of People’s United’s basic and diluted earnings per common share (“EPS”), reflecting the application of the two-class method, as described below: Three Months Ended Nine Months Ended (in millions, except per common share data) 2019 2018 2019 2018 Net income available to common shareholders $ 131.6 $ 113.5 $ 372.5 $ 324.6 Dividends paid on and undistributed earnings allocated to (0.1) — (0.2) (0.2) Earnings attributable to common shareholders $ 131.5 $ 113.5 $ 372.3 $ 324.4 Weighted average common shares outstanding for basic EPS 391.7 341.4 384.6 340.6 Effect of dilutive equity-based awards 2.8 3.6 3.2 3.9 Weighted average common shares and common-equivalent 394.5 345.0 387.8 344.5 EPS: Basic $ 0.34 $ 0.33 $ 0.97 $ 0.95 Diluted 0.33 0.33 0.96 0.94 Unvested share-based payment awards, which include the right to receive non-forfeitable dividends or dividend equivalents, are considered to participate with common stock in undistributed earnings for purposes of computing EPS. Companies that have such participating securities, including People’s United, are required to calculate basic and diluted EPS using the two-class method. Restricted stock awards granted by People’s United prior to 2017 are considered participating securities. Calculations of EPS under the two-class method (i) exclude from the numerator any dividends paid or owed on participating securities and any undistributed earnings considered to be attributable to participating securities and (ii) exclude from the denominator the dilutive impact of the participating securities. All unallocated Employee Stock Ownership Plan (“ESOP”) common shares and all common shares accounted for as treasury shares have been excluded from the calculation of basic and diluted EPS. Anti-dilutive equity-based awards totaling 7.2 million shares and 7.1 million shares for the three and nine months ended September 30, 2019, respectively, and 6.8 million shares for both the three and nine months ended September 30, 2018, have also been excluded from the calculation of diluted EPS.

Goodwill and Other Acquisition-

Goodwill and Other Acquisition-Related Intangible Assets	9 Months Ended
Goodwill and Other Acquisition-Related Intangible Assets	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Acquisition-Related Intangible Assets	NOTE 7. GOODWILL AND OTHER ACQUISITION-RELATED INTANGIBLE ASSETS Changes in the carrying amounts of People’s United’s goodwill are summarized as follows for the nine months ended September 30, 2019 and 2018, respectively. Operating Segment (in millions) Commercial Banking Retail Banking Wealth Management Total Balance at December 31, 2018 $ 1,759.4 $ 835.3 $ 91.0 $ 2,685.7 Acquisition of: VAR 37.5 — — 37.5 BSB Bancorp 49.3 95.6 — 144.9 Balance at September 30, 2019 $ 1,846.2 $ 930.9 $ 91.0 $ 2,868.1 Operating Segment (in millions) Commercial Banking Retail Banking Wealth Management Total Balance at December 31, 2017 $ 1,600.3 $ 720.1 $ 91.0 $ 2,411.4 Acquisition of Vend Lease Company 23.8 — — 23.8 Balance at September 30, 2018 $ 1,624.1 $ 720.1 $ 91.0 $ 2,435.2 Recent acquisitions have been undertaken with the objective of expanding the Company’s business, both geographically and through product offerings, as well as realizing synergies and economies of scale by combining with the acquired entities. For these reasons, a market-based premium was paid for the acquired entities which, in turn, resulted in the recognition of goodwill, representing the excess of the respective purchase prices over the estimated fair value of the net assets acquired. All of People’s United’s tax deductible goodwill was created in transactions in which the Company purchased the assets of the target (as opposed to purchasing the issued and outstanding stock of the target). At September 30, 2019 and December 31, 2018 , tax deductible goodwill totaled $137.2 million and $71.0 million, respectively. People’s United’s other acquisition-related intangible assets totaled $196.8 million and $180.0 million at September 30, 2019 and December 31, 2018, respectively. At September 30, 2019, the carrying amounts of other acquisition-related intangible assets were as follows: core deposit intangible ($91.8 million); trade name intangible ($54.1 million); client relationships intangible ($18.4 million); trust relationships intangible ($9.3 million); insurance relationships intangible ($4.0 million); favorable lease agreements ($2.4 million); non-compete agreements ($0.3 million); and mutual fund management contracts, which are not amortized ($16.5 million). Amortization expense of other acquisition-related intangible assets totaled $8.0 million and $4.9 million for the three months ended September 30, 2019 and 2018, respectively, and $22.7 million and $14.9 million for the nine months ended September 30, 2019 and 2018, respectively. Scheduled amortization expense attributable to other acquisition-related intangible assets for the full-year of 2019 and each of the next five years is as follows: $30.6 million in 2019; $29.7 million in 2020; $27.0 million in 2021; $24.6 million in 2022; $18.7 million in 2023; and $17.0 million in 2024. There were no impairment losses relating to goodwill or other acquisition-related intangible assets recorded in the Consolidated Statements of Income during the nine months ended September 30, 2019 and 2018.

Employee Benefit Plans

Employee Benefit Plans	9 Months Ended
Employee Benefit Plans	Sep. 30, 2019
Retirement Benefits [Abstract]
Employee Benefit Plans	NOTE 8. EMPLOYEE BENEFIT PLANS People’s United Employee Pension and Other Postretirement Plans People’s United maintains a qualified noncontributory defined benefit pension plan (the “People’s Qualified Plan”) that covers substantially all full-time and part-time employees who (i) meet certain age and length of service requirements and (ii) were employed by the Bank prior to August 14, 2006. Benefits are based upon the employee’s years of credited service and either the average compensation for the last five years or the average compensation for the five New employees of the Bank starting on or after August 14, 2006 are not eligible to participate in the People’s Qualified Plan. Instead, the Bank makes contributions on behalf of these employees to a qualified defined contribution plan in an annual amount equal to 3% of the employee’s eligible compensation. Employee participation in this plan is restricted to employees who (i) are at least 18 years of age and (ii) worked at least 1,000 hours in a year. Both full-time and part-time employees are eligible to participate as long as they meet these requirements. In July 2011, the Bank amended the People’s Qualified Plan to “freeze”, effective December 31, 2011, the accrual of pension benefits for People’s Qualified Plan participants. As such, participants will not earn any additional benefits after that date. Instead, effective January 1, 2012, the Bank began making contributions on behalf of these participants to a qualified defined contribution plan in an annual amount equal to 3% of the employee’s eligible compensation. In addition to the People’s Qualified Plan, People’s United continues to maintain a qualified defined benefit pension plan that covers former First Connecticut Bancorp, Inc. ("First Connecticut") employees who meet certain eligibility requirements (the “First Connecticut Qualified Plan”). All benefits under this plan were frozen effective February 28, 2013. People’s United’s funding policy is to contribute the amounts required by applicable regulations, although additional amounts may be contributed from time to time. People’s United also maintains (i) unfunded, nonqualified supplemental plans to provide retirement benefits to certain senior officers (the “People’s Supplemental Plans”) and (ii) an unfunded plan that provides retirees with optional medical, dental and life insurance benefits (the “People’s Postretirement Plan”). People’s United accrues the cost of these postretirement benefits over the employees’ years of service to the date of their eligibility for such benefit. People’s United also continues to maintain for certain eligible former First Connecticut employees (i) an unfunded, nonqualified supplemental retirement plan (the “First Connecticut Supplemental Plan”) and (ii) unfunded plans that provide medical, dental and life insurance benefits (the “First Connecticut Postretirement Plans”). Components of net periodic benefit (income) expense and other amounts recognized in other comprehensive income (loss) for (i) the People’s Qualified Plan, the First Connecticut Qualified Plan, the People's Supplemental Plans and the First Connecticut Supplemental Plan (together the “Pension Plans”) and (ii) the People's Postretirement Plan and the First Connecticut Postretirement Plans (together the "Other Postretirement Plans") are as follows: Pension Plans Other Three months ended September 30 (in millions) 2019 2018 2019 2018 Net periodic benefit (income) expense: Interest cost $ 5.7 $ 4.9 $ 0.2 $ 0.2 Expected return on plan assets (11.4) (10.9) — — Recognized net actuarial loss 1.3 2.0 0.1 — Recognized prior service credit — — — — Settlements 0.4 (0.5) — — Net periodic benefit (income) expense (1) $ (4.0) $ (4.5) $ 0.3 $ 0.2 Pension Plans Other Postretirement Plans Nine months ended September 30 (in millions) 2019 2018 2019 2018 Net periodic benefit (income) expense: Interest cost $ 17.1 $ 14.6 $ 0.7 $ 0.6 Expected return on plan assets (34.3) (32.7) — — Recognized net actuarial loss 4.0 6.0 0.1 0.2 Recognized prior service credit — (0.2) — — Settlements 1.3 0.4 — — Net periodic benefit (income) expense (11.9) (11.9) 0.8 0.8 Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss): Net actuarial loss (4.0) (6.0) (0.1) (0.2) Prior service credit — 0.2 — — Total pre-tax changes recognized in other comprehensive income (loss) (4.0) (5.8) (0.1) (0.2) Total recognized in net periodic benefit (income) expense and other comprehensive income (loss) $ (15.9) $ (17.7) $ 0.7 $ 0.6 Employee Stock Ownership Plan In April 2007, People’s United established an ESOP. At that time, People’s United loaned the ESOP $216.8 million to purchase 10,453,575 shares of People’s United common stock in the open market. In order for the ESOP to repay the loan, People’s United expects to make annual cash contributions of approximately $18.8 million until 2036. Such cash contributions may be reduced by the cash dividends paid on unallocated ESOP shares, which, for the nine months ended September 30, 2019, totaled $3.3 million. At September 30, 2019, the loan balance totaled $176.5 million. Employee participation in this plan is restricted to those employees who (i) are at least 18 years of age and (ii) worked at least 1,000 hours within 12 months of their hire date or any plan year (January 1 to December 31) after their date of hire. Employees meeting the aforementioned eligibility criteria during the plan year must continue to be employed as of the last day of the plan year in order to receive an allocation of shares for that plan year. Shares of People’s United common stock are held by the ESOP and allocated to eligible participants annually based upon a percentage of each participant’s eligible compensation. Since the ESOP was established, a total of 4,442,769 shares of People’s United common stock have been allocated or committed to be released to participants’ accounts. At September 30, 2019, 6,010,806 shares of People’s United common stock, with a fair value of $94.0 million at that date, have not been allocated or committed to be released. Compensation expense related to the ESOP is recognized at an amount equal to the number of common shares committed to be released by the ESOP for allocation to participants’ accounts multiplied by the average fair value of People’s United’s common stock during the reporting period. The difference between the fair value of the shares of People’s United’s common stock committed to be released and the cost of those common shares is recorded as a credit to additional paid-in capital (if fair value exceeds cost) or, to the extent that no such credits remain in additional paid-in capital, as a charge to retained earnings (if fair value is less than cost). Expense recognized for the ESOP totaled $4.2 million and $4.8 million for the nine months ended September 30, 2019 and 2018, respectively.

Legal Proceedings

Legal Proceedings	9 Months Ended
Legal Proceedings	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Legal Proceedings	NOTE 9. LEGAL PROCEEDINGS In the normal course of business, People’s United is subject to various legal proceedings. Management has discussed with legal counsel the nature of these legal proceedings and, based on the advice of counsel and the information currently available, believes that the eventual outcome of these legal proceedings will not have a material adverse effect on People’s United’s financial condition, results of operations or liquidity.

Segment Information

Segment Information	9 Months Ended
Segment Information	Sep. 30, 2019
Segment Reporting [Abstract]
Segment Information	NOTE 10. SEGMENT INFORMATION See “Segment Results” included in Item 2 for segment information for the three and nine months ended September 30, 2019 and 2018.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
Fair Value Measurements	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	NOTE 11. FAIR VALUE MEASUREMENTS Accounting standards related to fair value measurements define fair value, provide a framework for measuring fair value and establish related disclosure requirements. Broadly, fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. Accordingly, an “exit price” approach is required in determining fair value. In support of this principle, a fair value hierarchy has been established that prioritizes the inputs used to measure fair value, requiring entities to maximize the use of market or observable inputs (as more reliable measures) and minimize the use of unobservable inputs. Observable inputs reflect market data obtained from independent sources, while unobservable inputs generally require significant management judgment. The three levels within the fair value hierarchy are as follows: • Level 1 – Unadjusted quoted market prices for identical assets or liabilities in active markets that the entity has the ability to access at the measurement date (such as active exchange-traded equity securities or mutual funds and certain U.S. and government agency debt securities). • Level 2 – Observable inputs other than quoted prices included in Level 1, such as: ▪ quoted prices for similar assets or liabilities in active markets (such as U.S. agency and GSE mortgage-backed securities); ▪ quoted prices for identical or similar assets or liabilities in less active markets (such as certain U.S. and government agency debt securities, and corporate and municipal debt securities that trade infrequently); and ▪ other inputs that (i) are observable for substantially the full term of the asset or liability (e.g. interest rates, yield curves, prepayment speeds, default rates, etc.) or (ii) can be corroborated by observable market data (such as interest rate and currency derivatives and certain other securities). • Level 3 – Valuation techniques that require unobservable inputs that are supported by little or no market activity and are significant to the fair value measurement of the asset or liability (such as pricing models, discounted cash flow methodologies and similar techniques that typically reflect management’s own estimates of the assumptions a market participant would use in pricing the asset or liability). People’s United maintains policies and procedures to value assets and liabilities using the most relevant data available. Described below are the valuation methodologies used by People’s United and the resulting fair values for those financial instruments measured at fair value on both a recurring and a non-recurring basis. For those financial instruments not measured at fair value either on a recurring or non-recurring basis, disclosure of each instrument’s carrying amount and estimated fair value has been provided. Recurring Fair Value Measurements Trading Debt Securities, Equity Securities and Debt Securities Available-For-Sale When available, People’s United uses quoted market prices for identical securities received from an independent, nationally-recognized, third-party pricing service (as discussed further below) to determine the fair value of investment securities such as U.S. Treasury and agency securities and equity securities that are included in Level 1. When quoted market prices for identical securities are unavailable, People’s United uses prices provided by the independent pricing service based on recent trading activity and other observable information including, but not limited to, market interest rate curves, referenced credit spreads and estimated prepayment rates where applicable. These investments include certain U.S. and government agency debt securities, corporate and municipal debt securities, and GSE mortgage-backed securities, all of which are included in Level 2. The Company’s available-for-sale debt securities are primarily comprised of GSE mortgage-backed securities. The fair value of these securities is based on prices obtained from the independent pricing service. The pricing service uses various techniques to determine pricing for the Company’s mortgage-backed securities, including option pricing and discounted cash flow analysis. The inputs include benchmark yields, reported trades, broker/dealer quotes, issuer spreads, benchmark securities, bids, offers, reference data, monthly payment information and collateral performance. At both September 30, 2019 and December 31, 2018, the entire available-for-sale mortgage-backed securities portfolio was comprised of 10- and 15-year GSE securities. An active market exists for securities that are similar to the Company’s GSE mortgage-backed securities, making observable inputs readily available. Changes in the prices obtained from the pricing service are analyzed from month to month, taking into consideration changes in market conditions including changes in mortgage spreads, changes in U.S. Treasury security yields and changes in generic pricing of securities with similar duration. As a further point of validation, the Company generates its own month-end fair value estimate for all mortgage-backed securities, and state and municipal securities. While the Company has not adjusted the prices obtained from the independent pricing service, any notable differences between those prices and the Company’s estimates are subject to further analysis. This additional analysis may include a review of prices provided by other independent parties, a yield analysis, a review of average life changes using Bloomberg analytics and a review of historical pricing for the particular security. Based on management’s review of the prices provided by the pricing service, the fair values incorporate observable market inputs used by market participants at the measurement date and, as such, are classified as Level 2 securities. Other Assets As discussed in Note 8, certain unfunded, nonqualified supplemental plans have been established to provide retirement benefits to certain senior officers. People’s United has funded two trusts to provide benefit payments to the extent such benefits are not paid directly by People’s United, the assets of which are included in other assets in the Consolidated Statements of Condition. When available, People’s United determines the fair value of the trust assets using quoted market prices for identical securities received from a third-party nationally recognized pricing service. Derivatives People’s United values its derivatives using internal models that are based on market or observable inputs including interest rate curves and forward/spot prices for selected currencies. Derivative assets and liabilities included in Level 2 represent interest rate swaps and caps, foreign exchange contracts, risk participation agreements, forward commitments to sell residential mortgage loans and interest rate-lock commitments on residential mortgage loans. The following tables summarize People’s United’s financial instruments that are measured at fair value on a recurring basis: Fair Value Measurements Using As of September 30, 2019 (in millions) Level 1 Level 2 Level 3 Total Financial assets: Trading debt securities: U.S. Treasury $ 9.3 $ — $ — $ 9.3 Debt securities available-for-sale: U.S. Treasury and agency 688.1 — — 688.1 GSE mortgage-backed securities — 2,290.6 — 2,290.6 Equity securities 7.8 — — 7.8 Other assets: Exchange-traded funds 45.3 — — 45.3 Mutual funds 3.8 — — 3.8 Interest rate swaps — 421.1 — 421.1 Interest rate caps — 2.1 — 2.1 Foreign exchange contracts — 1.4 — 1.4 Forward commitments to sell residential — 0.4 — 0.4 Total $ 754.3 $ 2,715.6 $ — $ 3,469.9 Financial liabilities: Interest rate swaps $ — $ 74.3 $ — $ 74.3 Interest rate caps — 2.1 — 2.1 Risk participation agreements — 0.2 — 0.2 Foreign exchange contracts — 1.3 — 1.3 Interest rate-lock commitments on residential — 0.5 — 0.5 Total $ — $ 78.4 $ — $ 78.4 Fair Value Measurements Using As of December 31, 2018 (in millions) Level 1 Level 2 Level 3 Total Financial assets: Trading debt securities: U.S. Treasury $ 8.4 $ — $ — $ 8.4 Debt securities available-for-sale: U.S. Treasury and agency 678.0 — — 678.0 GSE mortgage-backed securities — 2,443.0 — 2,443.0 Equity securities 8.1 — — 8.1 Other assets: Exchange-traded funds 35.5 — — 35.5 Mutual funds 20.6 — — 20.6 Fixed income securities — 0.3 — 0.3 Interest rate swaps — 98.9 — 98.9 Interest rate caps — 3.1 — 3.1 Foreign exchange contracts — 0.9 — 0.9 Forward commitments to sell residential — 0.1 — 0.1 Total $ 750.6 $ 2,546.3 $ — $ 3,296.9 Financial liabilities: Interest rate swaps $ — $ 135.0 $ — $ 135.0 Interest rate caps — 3.1 — 3.1 Risk participation agreements (1) — — — — Foreign exchange contracts — 0.8 — 0.8 Interest rate-lock commitments on residential — 0.1 — 0.1 Total $ — $ 139.0 $ — $ 139.0 1. At December 31, 2018, the fair value of risk participation agreements totaled less than $0.1 million (see Note 12). Non-Recurring Fair Value Measurements Loans Held-for-Sale Residential mortgage loans held-for-sale are recorded at the lower of cost or fair value and are therefore measured at fair value on a non-recurring basis. When available, People’s United uses observable secondary market data, including pricing on recent closed market transactions for loans with similar characteristics. Accordingly, such loans are classified as Level 2 measurements. When observable data is unavailable, valuation methodologies using current market interest rate data adjusted for inherent credit risk are used, and such loans are included in Level 3. Impaired Loans Loan impairment is deemed to exist when full repayment of principal and interest according to the contractual terms of the loan is no longer probable. Impaired loans are reported based on one of three measures: (i) the present value of expected future cash flows discounted at the loan’s original effective interest rate; (ii) the loan’s observable market price; or (iii) the fair value of the collateral (less estimated cost to sell) if the loan is collateral dependent. Accordingly, certain impaired loans may be subject to measurement at fair value on a non-recurring basis. People’s United has estimated the fair values of these assets using Level 3 inputs, such as discounted cash flows based on inputs that are largely unobservable and, instead, reflect management’s own estimates of the assumptions a market participant would use in pricing such loans and/or the fair value of collateral based on independent third-party appraisals for collateral-dependent loans. Such appraisals are based on the market and/or income approach to value and are subject to a discount (to reflect estimated cost to sell) that generally approximates 10%. REO and Repossessed Assets REO and repossessed assets are recorded at the lower of cost or fair value, less estimated selling costs, and are therefore measured at fair value on a non-recurring basis. People’s United has estimated the fair values of these assets using Level 3 inputs, such as independent third-party appraisals and price opinions. Such appraisals are based on the market and/or income approach to value and are subject to a discount (to reflect estimated cost to sell) that generally approximates 10%. Assets that are acquired through loan default are recorded as held-for-sale initially at the lower of the recorded investment in the loan or fair value (less estimated selling costs) upon the date of foreclosure/repossession. Subsequent to foreclosure/repossession, valuations are updated periodically and the carrying amounts of these assets may be reduced further. The following tables summarize People’s United’s assets that are measured at fair value on a non-recurring basis: Fair Value Measurements Using As of September 30, 2019 (in millions) Level 1 Level 2 Level 3 Total Loans held-for-sale (1) $ — $ 24.8 $ — $ 24.8 Impaired loans (2) — — 48.4 48.4 REO and repossessed assets (3) — — 26.3 26.3 Total $ — $ 24.8 $ 74.7 $ 99.5 Fair Value Measurements Using As of December 31, 2018 (in millions) Level 1 Level 2 Level 3 Total Loans held-for-sale (1) $ — $ 19.5 $ — $ 19.5 Impaired loans (2) — — 55.2 55.2 REO and repossessed assets (3) — — 18.1 18.1 Total $ — $ 19.5 $ 73.3 $ 92.8 1. Consists of residential mortgage loans; no fair value adjustments were recorded for the nine months ended September 30, 2019 and 2018. 2. Represents the recorded investment in originated impaired loans with a related allowance for loan losses measured in accordance with applicable accounting guidance. The total consists of $35.5 million of Commercial loans and $12.9 million of Retail loans at September 30, 2019. The provision for loan losses on impaired loans totaled $5.3 million and $7.7 million for the nine months ended September 30, 2019 and 2018, respectively. 3. Represents: (i) $12.3 million of residential REO; (ii) $7.7 million of commercial REO; and (iii) $6.3 million of repossessed assets at September 30, 2019. Charge-offs to the allowance for loan losses related to loans that were transferred to REO or repossessed assets totaled $2.1 million and $1.0 million for the nine months ended September 30, 2019 and 2018, respectively. Write downs and net (gains) loss on sale of foreclosed/repossessed assets charged to non-interest expense totaled $(0.3) million and $0.1 million for the same periods. Financial Assets and Financial Liabilities Not Measured at Fair Value The following tables summarize the carrying amounts, estimated fair values and placement in the fair value hierarchy of People’s United’s financial instruments that are not measured at fair value either on a recurring or non-recurring basis: Carrying Amount Estimated Fair Value Measurements Using As of September 30, 2019 (in millions) Level 1 Level 2 Level 3 Total Financial assets: Cash and due from banks $ 635.2 $ 635.2 $ — $ — $ 635.2 Short-term investments 157.8 — 157.8 — 157.8 Debt securities held-to-maturity 3,805.4 — 3,970.0 1.5 3,971.5 FHLB and FRB stock 334.0 — 334.0 — 334.0 Total loans, net (1) 38,487.0 — 9,064.9 29,474.3 38,539.2 Financial liabilities: Time deposits 8,100.4 — 8,120.9 — 8,120.9 Other deposits 30,473.1 — 30,473.1 — 30,473.1 FHLB advances 2,948.5 — 2,948.8 — 2,948.8 Federal funds purchased 1,365.0 — 1,365.0 — 1,365.0 Customer repurchase agreements 315.6 — 315.6 — 315.6 Notes and debentures 915.7 — 936.8 — 936.8 1. Excludes impaired loans totaling $48.4 million measured at fair value on a non-recurring basis. Carrying Amount Estimated Fair Value Measurements Using As of December 31, 2018 (in millions) Level 1 Level 2 Level 3 Total Financial assets: Cash and due from banks $ 665.7 $ 665.7 $ — $ — $ 665.7 Short-term investments 266.3 — 266.3 — 266.3 Debt securities held-to-maturity 3,792.3 — 3,774.4 1.5 3,775.9 FHLB and FRB stock 303.4 — 303.4 — 303.4 Total loans, net (1) 34,945.8 — 7,806.1 26,800.2 34,606.3 Financial liabilities: Time deposits 6,916.2 — 6,884.0 — 6,884.0 Other deposits 29,242.8 — 29,242.8 — 29,242.8 FHLB advances 2,404.5 — 2,404.5 — 2,404.5 Federal funds purchased 845.0 — 845.0 — 845.0 Customer repurchase agreements 332.9 — 332.9 — 332.9 Other borrowings 11.0 — 11.0 — 11.0 Notes and debentures 895.8 — 893.4 — 893.4 1. Excludes impaired loans totaling $55.2 million measured at fair value on a non-recurring basis.

Derivative Financial Instrument

Derivative Financial Instruments and Hedging Activities	9 Months Ended
Derivative Financial Instruments and Hedging Activities	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments and Hedging Activities	NOTE 12. DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES People’s United uses derivative financial instruments as components of its market risk management (principally to manage interest rate risk (“IRR”)). Certain other derivatives are entered into in connection with transactions with commercial customers. Derivatives are not used for speculative purposes. All derivatives are recognized as either assets or liabilities in the Consolidated Statements of Condition, reported at fair value and presented on a gross basis. Until a derivative is settled, a favorable change in fair value results in an unrealized gain that is recognized as an asset, while an unfavorable change in fair value results in an unrealized loss that is recognized as a liability. The Company generally applies hedge accounting to its derivatives used for market risk management purposes. Hedge accounting is permitted only if specific criteria are met, including a requirement that a highly effective relationship exist between the derivative instrument and the hedged item, both at inception of the hedge and on an ongoing basis. The hedge accounting method depends upon whether the derivative instrument is classified as a fair value hedge (i.e. hedging an exposure related to a recognized asset or liability, or a firm commitment) or a cash flow hedge (i.e. hedging an exposure related to the variability of future cash flows associated with a recognized asset or liability, or a forecasted transaction). Changes in the fair value of effective fair value hedges are recognized in current earnings (with the change in fair value of the hedged asset or liability also recorded in earnings). Changes in the fair value of effective cash flow hedges are recognized in other comprehensive income (loss) until earnings are affected by the variability in cash flows of the designated hedged item. Ineffective portions of hedge results are recognized in current earnings. Changes in the fair value of derivatives for which hedge accounting is not applied are recognized in current earnings. People’s United formally documents at inception all relationships between the derivative instruments and the hedged items, as well as its risk management objectives and strategies for undertaking the hedge transactions. This process includes linking all derivatives that are designated as hedges to specific assets and liabilities, or to specific firm commitments or forecasted transactions. People’s United also formally assesses, both at inception of the hedge and on an ongoing basis, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in the fair values or cash flows of the hedged items. If it is determined that a derivative is not highly effective or has ceased to be a highly effective hedge, People’s United would discontinue hedge accounting prospectively. Gains or losses resulting from the termination of a derivative accounted for as a cash flow hedge remain in AOCL and are amortized to earnings over the remaining period of the former hedging relationship, provided the hedged item continues to be outstanding or it is probable the forecasted transaction will occur. People’s United uses the dollar offset method, regression analysis and scenario analysis to assess hedge effectiveness at inception and on an ongoing basis. Such methods are chosen based on the nature of the hedge strategy and are used consistently throughout the life of the hedging relationship. Certain derivative financial instruments are offered to commercial customers to assist them in meeting their financing and investing objectives and for their risk management purposes. These derivative financial instruments consist primarily of interest rate swaps and caps, but also include foreign exchange contracts. The interest rate and foreign exchange risks associated with customer interest rate swaps and caps and foreign exchange contracts are mitigated by entering into similar derivatives having essentially offsetting terms with institutional counterparties. Interest rate-lock commitments extended to borrowers relate to the origination of residential mortgage loans. To mitigate the IRR inherent in these commitments, People’s United enters into mandatory delivery and best efforts contracts to sell adjustable-rate and fixed-rate residential mortgage loans (servicing released). Forward commitments to sell and interest rate-lock commitments on residential mortgage loans are considered derivatives and their respective estimated fair values are adjusted based on changes in interest rates. Changes in the fair value of derivatives for which hedge accounting is not applied are recognized in current earnings, including customer derivatives, interest-rate lock commitments and forward sale commitments. By using derivatives, People’s United is exposed to credit risk to the extent that counterparties to the derivative contracts do not perform as required. Should a counterparty fail to perform under the terms of a derivative contract, the Company’s counterparty credit risk is equal to the amount reported as a derivative asset in the Consolidated Statements of Condition. In accordance with the Company’s balance sheet offsetting policy (see Note 13), amounts reported as derivative assets represent derivative contracts in a gain position, without consideration for derivative contracts in a loss position with the same counterparty (to the extent subject to master netting arrangements) and posted collateral. People’s United seeks to minimize counterparty credit risk through credit approvals, limits, monitoring procedures, execution of master netting arrangements and obtaining collateral, where appropriate. Counterparties to People’s United’s derivatives include major financial institutions and exchanges that undergo comprehensive and periodic internal credit analysis as well as maintain investment grade credit ratings from the major credit rating agencies. As such, management believes the risk of incurring credit losses on derivative contracts with those counterparties is remote and losses, if any, would be immaterial. Certain of People’s United’s derivative contracts contain provisions establishing collateral requirements (subject to minimum collateral posting thresholds) based on the Company’s external credit rating. If the Company’s senior unsecured debt rating were to fall below the level generally recognized as investment grade, the counterparties to such derivative contracts could require additional collateral on those derivative transactions in a net liability position (after considering the effect of master netting arrangements and posted collateral). The aggregate fair value of derivative instruments with such credit-related contingent features that were in a net liability position at September 30, 2019 was $1.4 million, for which People’s United had posted collateral of $0.8 million in the normal course of business. If the Company’s senior unsecured debt rating had fallen below investment grade as of that date, $0.6 million in additional collateral would have been required. The following sections further discuss each class of derivative financial instrument used by People’s United, including management’s principal objectives and risk management strategies. Interest Rate Swaps People’s United may, from time to time, enter into interest rate swaps that are used to manage IRR associated with certain interest-earning assets and interest-bearing liabilities. The Bank has entered into pay floating/receive fixed interest rate swaps to reduce its IRR exposure to the variability in interest cash flows on certain floating-rate commercial loans. The Bank has agreed with the swap counterparties to exchange, at specified intervals, the difference between fixed-rate and floating-rate interest amounts calculated based on notional amounts totaling $210 million. The floating-rate interest payments made under the swaps are calculated using the same floating rate received on the commercial loans. The swaps effectively convert the floating-rate one-month LIBOR interest payments received on the commercial loans to a fixed rate and consequently reduce the Bank’s exposure to variability in short-term interest rates. These swaps are accounted for as cash flow hedges. The Bank has entered into a pay floating/receive fixed interest rate swap to hedge the change in fair value due to changes in interest rates of the Bank’s $400 million subordinated notes. The Bank has agreed with the swap counterparty to exchange, at specified intervals, the difference between fixed-rate and floating-rate interest amounts calculated based on a notional amount of $375 million. The fixed-rate interest payments received on the swap will essentially offset the fixed-rate interest payments made on these notes, notwithstanding the notional difference between these notes and the swap. The floating-rate interest amounts paid under the swap are calculated based on three-month LIBOR plus 126.5 basis points. The swap effectively converts the fixed-rate subordinated notes to a floating-rate liability. This swap is accounted for as a fair value hedge. Customer Derivatives People’s United enters into interest rate swaps and caps with certain of its commercial customers. In order to minimize its risk, these customer interest rate swaps (pay floating/receive fixed) and caps have been offset with essentially matching interest rate swaps (pay fixed/receive floating) and caps with People’s United’s institutional counterparties. Hedge accounting has not been applied for these derivatives. Accordingly, changes in the fair value of all such interest rate swaps and caps are recognized in current earnings. Foreign Exchange Contracts Foreign exchange contracts are commitments to buy or sell foreign currency on a future date at a contractual price. People’s United uses these instruments on a limited basis to (i) eliminate its exposure to fluctuations in currency exchange rates on certain of its commercial loans that are denominated in foreign currencies and (ii) provide foreign exchange contracts on behalf of commercial customers within credit exposure limits. Gains and losses on foreign exchange contracts substantially offset the translation gains and losses on the related loans. Risk Participation Agreements People’s United enters into risk participation agreements under which it may either assume or sell credit risk associated with a borrower’s performance under certain interest rate derivative contracts. In those instances in which People’s United has assumed credit risk, it is not a party to the derivative contract and has entered into the risk participation agreement because it is also a party to the related loan agreement with the borrower. In those instances in which People’s United has sold credit risk, it is a party to the derivative contract and has entered into the risk participation agreement because it sold a portion of the related loan. People’s United manages its credit risk under risk participation agreements by monitoring the creditworthiness of the borrower, based on its normal credit review process. The notional amounts of the risk participation agreements reflect People’s United’s pro-rata share of the derivative contracts, consistent with its share of the related loans. Forward Commitments to Sell Residential Mortgage Loans and Related Interest Rate-Lock Commitments People’s United enters into forward commitments to sell adjustable-rate and fixed-rate residential mortgage loans (all to be sold servicing released) in order to reduce the market risk associated with originating loans for sale in the secondary market. In order to fulfill a forward commitment, People’s United delivers originated loans at prices or yields specified by the contract. The risks associated with such contracts arise from the possible inability of counterparties to meet the contract terms or People’s United’s inability to originate the necessary loans. Gains and losses realized on the forward contracts are reported in the Consolidated Statements of Income as a component of the net gains on sales of residential mortgage loans. In the normal course of business, People’s United will commit to an interest rate on a mortgage loan application at the time of application, or anytime thereafter. The risks associated with these interest rate-lock commitments arise if market interest rates change prior to the closing of these loans. Both forward sales commitments and interest rate-lock commitments made to borrowers on held-for-sale loans are accounted for as derivatives, with changes in fair value recognized in current earnings. Interest Rate Locks In connection with its planned issuance of senior notes in the fourth quarter of 2012, People’s United entered into U.S. Treasury forward interest rate locks (“T-Locks”) to hedge the risk that the 10-year U.S. Treasury yield component of the underlying coupon of the fixed-rate senior notes would rise prior to establishing the fixed interest rate on the senior notes. Upon pricing the senior notes, the T-Locks were terminated and the unrealized gain of $0.9 million was included (on a net-of-tax basis) as a component of AOCL. The gain is being recognized as a reduction of interest expense over the ten-year period during which the hedged item ($500 million senior note issuance) affects earnings. The table below provides a summary of the notional amounts and fair values (presented on a gross basis) of derivatives outstanding: Fair Values (1) Notional Amounts Assets Liabilities (in millions) Type of Hedge Sept. 30, Dec 31, Sept. 30, Dec 31, 2018 Sept. 30, Dec 31, 2018 Derivatives Not Designated as Hedging Interest rate swaps: Commercial customers N/A $ 7,592.8 $ 7,455.9 $ 416.2 $ 76.3 $ 0.7 $ 102.6 Institutional counterparties N/A 7,599.6 7,161.3 4.9 22.6 73.6 32.4 Interest rate caps: Commercial customers N/A 264.2 329.1 2.1 0.6 — 2.5 Institutional counterparties N/A 264.2 329.1 — 2.5 2.1 0.6 Risk participation agreements (2) N/A 786.6 576.5 — — 0.2 — Foreign exchange contracts N/A 74.8 145.2 1.4 0.9 1.3 0.8 Forward commitments to sell N/A 34.8 9.5 0.4 0.1 — — Interest rate-lock commitments on N/A 54.9 13.6 — — 0.5 0.1 Total 425.0 103.0 78.4 139.0 Derivatives Designated as Hedging Interest rate swaps: Subordinated notes Fair value 375.0 375.0 — — — — Loans Cash flow 210.0 210.0 — — — — Total — — — — Total fair value of derivatives $ 425.0 $ 103.0 $ 78.4 $ 139.0 1. Assets are recorded in other assets and liabilities are recorded in other liabilities. 2. Fair value totaled less than $0.1 million at December 31, 2018. The following table summarizes the impact of People’s United’s derivatives on pre-tax income and AOCL: Type of Hedge Amount of Pre-Tax Gain (Loss) Recognized in Earnings (1) Amount of Pre-Tax Gain (Loss) Recognized in AOCL Nine months ended September 30 (in millions) 2019 2018 2019 2018 Derivatives Not Designated as Hedging Interest rate swaps: Commercial customers N/A $ 466.8 $ (177.1) $ — $ — Institutional counterparties N/A (451.3) 184.5 — — Interest rate caps: Commercial customers N/A 2.0 (0.7) — — Institutional counterparties N/A (2.0) 0.8 — — Foreign exchange contracts N/A 0.5 0.6 — — Risk participation agreements N/A 0.1 0.2 — — Forward commitments to sell N/A 0.3 — — — Interest rate-lock commitments on N/A (0.3) — — — Total 16.1 8.3 — — Derivatives Designated as Hedging Interest rate swaps Fair value (0.2) (1.8) — — Interest rate swaps Cash flow (1.1) (0.3) 2.1 (3.1) Interest rate locks Cash flow 0.1 0.1 — — Total (1.2) (2.0) 2.1 (3.1) Total $ 14.9 $ 6.3 $ 2.1 $ (3.1) 1. Amounts recognized in earnings are recorded in interest income, interest expense or other non-interest income for derivatives designated as hedging instruments and in other non-interest income for derivatives not designated as hedging instruments.

Balance Sheet Offsetting

Balance Sheet Offsetting	9 Months Ended
Balance Sheet Offsetting	Sep. 30, 2019
Offsetting [Abstract]
Balance Sheet Offsetting	NOTE 13. BALANCE SHEET OFFSETTING Assets and liabilities relating to certain financial instruments, including derivatives, may be eligible for offset in the Consolidated Statements of Condition and/or subject to enforceable master netting arrangements or similar agreements. People’s United’s derivative transactions with institutional counterparties are generally executed under International Swaps and Derivative Association (“ISDA”) master agreements, which include “right of set-off” provisions that provide for a single net settlement of all interest rate swap positions, as well as collateral, in the event of default on, or the termination of, any one contract. Nonetheless, the Company does not, except as indicated below, offset asset and liabilities under such arrangements in the Consolidated Statements of Condition. The Chicago Mercantile Exchange (“CME”) legally characterizes variation margin payments for over-the-counter derivatives that clear as settlements rather than collateral. Accordingly, the Company’s accounting policies classify, for accounting and presentation purposes, variation margin payments deemed to be legal settlements as a single unit of account with the related derivative(s). At both September 30, 2019 and December 31, 2018, this presentation impacted one of the Company’s institutional counterparties. As such, People’s United has, subject to the corresponding enforceable master netting arrangement, netted the institutional counterparty’s CME derivative position and offset the counterparty’s variation margin payments in the Consolidated Statement of Condition as of both dates. Collateral (generally in the form of marketable debt securities) pledged by counterparties in connection with derivative transactions is not reported in the Consolidated Statements of Condition unless the counterparty defaults. Collateral that has been pledged by People’s United to counterparties continues to be reported in the Consolidated Statements of Condition unless the Company defaults. The following tables provide a gross presentation, the effects of offsetting, and a net presentation of the Company’s financial instruments that are eligible for offset in the Consolidated Statements of Condition. The collateral amounts in these tables are limited to the outstanding balances of the related asset or liability (after netting is applied) and, therefore, instances of overcollateralization are not presented. In the tables below, the Net Amount Presented of the derivative assets and liabilities can be reconciled to the fair value of the Company’s derivative financial instruments in Note 12. The Company’s derivative contracts with commercial customers and customer repurchase agreements are not subject to master netting arrangements and, therefore, have been excluded from the tables below. Gross Amount Recognized Gross Amount Offset Net Amount Presented Gross Amounts Not Offset Financial Instruments Net Amount As of September 30, 2019 (in millions) Collateral Financial assets: Interest rate swaps: Counterparty A $ — $ — $ — $ — $ — $ — Counterparty B 0.1 — 0.1 (0.1) — — Counterparty C 0.1 — 0.1 (0.1) — — Counterparty D — — — — — — Counterparty E 4.5 — 4.5 — — 4.5 Other counterparties 0.2 — 0.2 (0.2) — — Foreign exchange contracts 1.4 — 1.4 — — 1.4 Total $ 6.3 $ — $ 6.3 $ (0.4) $ — $ 5.9 Financial liabilities: Interest rate swaps: Counterparty A $ 3.2 $ — $ 3.2 $ — $ (3.2) $ — Counterparty B 7.1 — 7.1 (0.1) (7.0) — Counterparty C 23.8 — 23.8 (0.1) (23.7) — Counterparty D 7.6 — 7.6 — (7.6) — Counterparty E — — — — — — Other counterparties 34.0 — 34.0 (0.2) (33.2) 0.6 Foreign exchange contracts 1.3 — 1.3 — — 1.3 Total $ 77.0 $ — $ 77.0 $ (0.4) $ (74.7) $ 1.9 Gross Amount Recognized Gross Amount Offset Net Amount Presented Gross Amounts Not Offset Financial Instruments Net Amount As of December 31, 2018 (in millions) Collateral Financial assets: Interest rate swaps: Counterparty A $ 3.1 $ — $ 3.1 $ (1.4) $ (1.7) $ — Counterparty B 2.5 — 2.5 (2.5) — — Counterparty C 4.8 — 4.8 (3.7) (1.1) — Counterparty D 3.6 — 3.6 (2.7) (0.1) 0.8 Counterparty E — — — — — — Other counterparties 11.1 — 11.1 (5.4) (5.7) — Foreign exchange contracts 0.9 — 0.9 — — 0.9 Total $ 26.0 $ — $ 26.0 $ (15.7) $ (8.6) $ 1.7 Financial liabilities: Interest rate swaps: Counterparty A $ 1.4 $ — $ 1.4 $ (1.4) $ — $ — Counterparty B 3.8 — 3.8 (2.5) (1.2) 0.1 Counterparty C 3.7 — 3.7 (3.7) — — Counterparty D 2.7 — 2.7 (2.7) — — Counterparty E 16.0 — 16.0 — — 16.0 Other counterparties 5.4 — 5.4 (5.4) — — Foreign exchange contracts 0.8 — 0.8 — — 0.8 Total $ 33.8 $ — $ 33.8 $ (15.7) $ (1.2) $ 16.9 Resale and repurchase agreements represent agreements to purchase/sell securities subject to an obligation to resell/repurchase the same or similar securities. People’s United accounts for securities resale agreements as secured lending transactions and securities repurchase agreements as secured borrowings since the transferor maintains effective control over the transferred securities and the transfer meets the other criteria for such accounting. The securities are pledged by the transferor as collateral and the transferee has the right by contract to repledge that collateral provided the same collateral is returned to the transferor upon maturity of the underlying agreement. The fair value of the pledged collateral approximates the recorded amount of the secured loan or borrowing. Decreases in the fair value of the transferred securities below an established threshold require the transferor to provide additional collateral. The following tables show the extent to which assets and liabilities exchanged under resale and repurchase agreements have been offset in the Consolidated Statements of Condition. These agreements: (i) are entered into simultaneously with the same financial institution counterparty; (ii) have the same principal amounts and inception/maturity dates; and (iii) are subject to a master netting arrangement that contains a conditional right of offset upon default. At September 30, 2019 and December 31, 2018, the Company posted as collateral marketable securities with fair values of $462.6 million and $461.3 million, respectively, and, in turn, accepted as collateral marketable securities with fair values of $458.2 million and $457.2 million, respectively. As of September 30, 2019 (in millions) Gross Amount Recognized Gross Amount Offset Net Amount Presented Total resale agreements $ 450.0 $ (450.0) $ — Total repurchase agreements $ 450.0 $ (450.0) $ — As of December 31, 2018 (in millions) Gross Amount Recognized Gross Amount Offset Net Amount Presented Total resale agreements $ 450.0 $ (450.0) $ — Total repurchase agreements $ 450.0 $ (450.0) $ —

Leases

Leases	9 Months Ended
Leases	Sep. 30, 2019
Leases [Abstract]
Leases	NOTE 14. LEASES Lessor Arrangements People's United provides equipment financing to its customers through a variety of lessor arrangements, some of which may include options to renew and/or for the lessee to purchase the leased equipment at the end of the lease term. Direct financing leases and sales-type leases (collectively, "lease financing receivables") are carried at the aggregate of lease payments receivable plus the estimated residual value of the leased assets and any initial direct costs incurred to originate these leases , less unearned income, which is accreted to interest income over the lease term using the interest method. The residual value component of a lease financing receivable represents the estimated fair value of the leased equipment at the end of the lease term. In establishing residual value estimates, the Company may rely on industry data, historical experience, independent appraisals and, where appropriate, information regarding product life cycle, product upgrades and competing products. Upon expiration of a lease, residual assets are remarketed, resulting in an extension of the lease by the lessee, a lease to a new customer or purchase of the residual asset by the lessee or another party. Impairment of residual values arises if the expected fair value is less than the carrying amount. The Company assesses its net investment in lease financing receivables (including residual values) for impairment on a quarterly basis with any impairment losses recognized in accordance with the impairment guidance for financial instruments. As such, net investment in lease financing receivables may be reduced by an allowance for credit losses with changes recognized as provision expense. The composition of the Company’s total net investment in lease financing receivables included within equipment financing loans in the Consolidated Statements of Condition was as follows: (in millions) September 30, 2019 Lease payments receivable $ 1,380.0 Estimated residual value of leased assets 128.4 Gross investment in lease financing receivables 1,508.4 Plus: Deferred origination costs 13.5 Less: Unearned income (154.4) Total net investment in lease financing receivables $ 1,367.5 The contractual maturities of the Company's lease financing receivables were as follows: (in millions) September 30, 2019 2019 (1) $ 229.7 2020 454.8 2021 357.7 2022 245.2 2023 137.0 Later years 84.0 Total $ 1,508.4 1. Contractual maturities for the three months remaining in 2019. Operating lease income, generated in connection with operating leases for which the Company acts as a lessor, is recognized on a straight-line basis over the lease term as a component of non-interest income in the Consolidated Statements of Income. Depreciation expense for assets under operating leases, which are included in other assets in the Consolidated Statements of Condition, is generally recorded on a straight-line basis over the lease term as a component of non-interest expense in the Consolidated Statements of Income. For the three months ended September 30, 2019, total lease income was $30.2 million, which consisted of $17.2 million from lease financing receivables and $13.0 million from operating leases. For the nine months ended September 30, 2019, total lease income was $87.6 million, which consisted of $49.2 million from lease financing receivables and $38.4 million from operating leases. Lessee Arrangements Substantially all of the Company’s lessee arrangements represent non-cancelable operating leases for real estate (primarily branch locations) and office equipment with terms extending through 2054. Under these arrangements, People's United records right-of-use ("ROU") assets and corresponding lease liabilities at lease commencement. Lease liabilities are recognized based on the present value of the remaining lease payments and discounted using the Company’s incremental borrowing rate for borrowings of similar term. ROU assets initially equal the related lease liability, adjusted for any lease payments made prior to the lease commencement and any lease incentives. Portions of certain properties are subleased for terms extending through 2024. At lease commencement, the Company considers renewal or termination options in the determination of the term of the lease. If it is reasonably certain that a renewal or termination option will be exercised, the effects of such options are included in the determination of the expected lease term. All leases are recorded with the exception of leases with an initial term of twelve months or less for which the Company made the short-term lease election. Within the Consolidated Statements of Condition, ROU assets are reported in other assets and the related lease liabilities are reported in other liabilities. In recognizing ROU assets and related lease liabilities, lease and non-lease components (such as taxes, insurance and common area maintenance costs) are accounted for separately as such amounts are generally readily determinable under the Company's lease contracts. Lease expense is recognized on a straight-line basis over the lease term and is recorded within occupancy and equipment expense in the Consolidated Statements of Income. Variable lease payments, which generally relate to the non-lease components noted above, are expensed as incurred. The following tables provide the components of lease cost and supplemental information: Three Months Ended Nine Months Ended (in millions) September 30, 2019 September 30, 2019 Operating lease cost $ 15.0 $ 45.4 Variable lease cost 2.0 6.4 Sublease income (0.3) (1.0) Net lease cost $ 16.7 $ 50.8 (dollars in millions) As of and for Nine Months Ended September 30, 2019 Lease ROU assets $ 235.6 Lease liabilities 260.5 Cash payments included in the measurement of lease liabilities reported in operating cash flows 45.8 ROU assets obtained in exchange for lessee operating lease liabilities (1) 30.3 Weighted average discount rate 3.28 % Weighted average remaining lease term (in years) 7.0 1. Amount excludes related transition adjustment (see Note 15). The contractual maturities of the Company's lease liabilities were as follows: (in millions) September 30, 2019 2019 (1) $ 15.1 2020 59.1 2021 56.7 2022 39.5 2023 28.3 Later years 102.8 Total lease payments 301.5 Less: Interest (41.0) Total lease liabilities $ 260.5 1. Contractual maturities for the three months remaining in 2019. At December 31, 2018, future minimum rental commitments under operating leases in excess of one year were: $65.4 million in 2019; $60.1 million in 2020; $56.4 million in 2021; $37.8 million in 2022; $26.1 million in 2023; and an aggregate of $88.5 million in 2024 through 2054. These amounts include variable lease payments which are excluded from the lessee maturity analysis presented above. There has been no significant change in the Company's expected future minimum lease payments since December 31, 2018.
Leases	NOTE 14. LEASES Lessor Arrangements People's United provides equipment financing to its customers through a variety of lessor arrangements, some of which may include options to renew and/or for the lessee to purchase the leased equipment at the end of the lease term. Direct financing leases and sales-type leases (collectively, "lease financing receivables") are carried at the aggregate of lease payments receivable plus the estimated residual value of the leased assets and any initial direct costs incurred to originate these leases , less unearned income, which is accreted to interest income over the lease term using the interest method. The residual value component of a lease financing receivable represents the estimated fair value of the leased equipment at the end of the lease term. In establishing residual value estimates, the Company may rely on industry data, historical experience, independent appraisals and, where appropriate, information regarding product life cycle, product upgrades and competing products. Upon expiration of a lease, residual assets are remarketed, resulting in an extension of the lease by the lessee, a lease to a new customer or purchase of the residual asset by the lessee or another party. Impairment of residual values arises if the expected fair value is less than the carrying amount. The Company assesses its net investment in lease financing receivables (including residual values) for impairment on a quarterly basis with any impairment losses recognized in accordance with the impairment guidance for financial instruments. As such, net investment in lease financing receivables may be reduced by an allowance for credit losses with changes recognized as provision expense. The composition of the Company’s total net investment in lease financing receivables included within equipment financing loans in the Consolidated Statements of Condition was as follows: (in millions) September 30, 2019 Lease payments receivable $ 1,380.0 Estimated residual value of leased assets 128.4 Gross investment in lease financing receivables 1,508.4 Plus: Deferred origination costs 13.5 Less: Unearned income (154.4) Total net investment in lease financing receivables $ 1,367.5 The contractual maturities of the Company's lease financing receivables were as follows: (in millions) September 30, 2019 2019 (1) $ 229.7 2020 454.8 2021 357.7 2022 245.2 2023 137.0 Later years 84.0 Total $ 1,508.4 1. Contractual maturities for the three months remaining in 2019. Operating lease income, generated in connection with operating leases for which the Company acts as a lessor, is recognized on a straight-line basis over the lease term as a component of non-interest income in the Consolidated Statements of Income. Depreciation expense for assets under operating leases, which are included in other assets in the Consolidated Statements of Condition, is generally recorded on a straight-line basis over the lease term as a component of non-interest expense in the Consolidated Statements of Income. For the three months ended September 30, 2019, total lease income was $30.2 million, which consisted of $17.2 million from lease financing receivables and $13.0 million from operating leases. For the nine months ended September 30, 2019, total lease income was $87.6 million, which consisted of $49.2 million from lease financing receivables and $38.4 million from operating leases. Lessee Arrangements Substantially all of the Company’s lessee arrangements represent non-cancelable operating leases for real estate (primarily branch locations) and office equipment with terms extending through 2054. Under these arrangements, People's United records right-of-use ("ROU") assets and corresponding lease liabilities at lease commencement. Lease liabilities are recognized based on the present value of the remaining lease payments and discounted using the Company’s incremental borrowing rate for borrowings of similar term. ROU assets initially equal the related lease liability, adjusted for any lease payments made prior to the lease commencement and any lease incentives. Portions of certain properties are subleased for terms extending through 2024. At lease commencement, the Company considers renewal or termination options in the determination of the term of the lease. If it is reasonably certain that a renewal or termination option will be exercised, the effects of such options are included in the determination of the expected lease term. All leases are recorded with the exception of leases with an initial term of twelve months or less for which the Company made the short-term lease election. Within the Consolidated Statements of Condition, ROU assets are reported in other assets and the related lease liabilities are reported in other liabilities. In recognizing ROU assets and related lease liabilities, lease and non-lease components (such as taxes, insurance and common area maintenance costs) are accounted for separately as such amounts are generally readily determinable under the Company's lease contracts. Lease expense is recognized on a straight-line basis over the lease term and is recorded within occupancy and equipment expense in the Consolidated Statements of Income. Variable lease payments, which generally relate to the non-lease components noted above, are expensed as incurred. The following tables provide the components of lease cost and supplemental information: Three Months Ended Nine Months Ended (in millions) September 30, 2019 September 30, 2019 Operating lease cost $ 15.0 $ 45.4 Variable lease cost 2.0 6.4 Sublease income (0.3) (1.0) Net lease cost $ 16.7 $ 50.8 (dollars in millions) As of and for Nine Months Ended September 30, 2019 Lease ROU assets $ 235.6 Lease liabilities 260.5 Cash payments included in the measurement of lease liabilities reported in operating cash flows 45.8 ROU assets obtained in exchange for lessee operating lease liabilities (1) 30.3 Weighted average discount rate 3.28 % Weighted average remaining lease term (in years) 7.0 1. Amount excludes related transition adjustment (see Note 15). The contractual maturities of the Company's lease liabilities were as follows: (in millions) September 30, 2019 2019 (1) $ 15.1 2020 59.1 2021 56.7 2022 39.5 2023 28.3 Later years 102.8 Total lease payments 301.5 Less: Interest (41.0) Total lease liabilities $ 260.5 1. Contractual maturities for the three months remaining in 2019. At December 31, 2018, future minimum rental commitments under operating leases in excess of one year were: $65.4 million in 2019; $60.1 million in 2020; $56.4 million in 2021; $37.8 million in 2022; $26.1 million in 2023; and an aggregate of $88.5 million in 2024 through 2054. These amounts include variable lease payments which are excluded from the lessee maturity analysis presented above. There has been no significant change in the Company's expected future minimum lease payments since December 31, 2018.
Leases	NOTE 14. LEASES Lessor Arrangements People's United provides equipment financing to its customers through a variety of lessor arrangements, some of which may include options to renew and/or for the lessee to purchase the leased equipment at the end of the lease term. Direct financing leases and sales-type leases (collectively, "lease financing receivables") are carried at the aggregate of lease payments receivable plus the estimated residual value of the leased assets and any initial direct costs incurred to originate these leases , less unearned income, which is accreted to interest income over the lease term using the interest method. The residual value component of a lease financing receivable represents the estimated fair value of the leased equipment at the end of the lease term. In establishing residual value estimates, the Company may rely on industry data, historical experience, independent appraisals and, where appropriate, information regarding product life cycle, product upgrades and competing products. Upon expiration of a lease, residual assets are remarketed, resulting in an extension of the lease by the lessee, a lease to a new customer or purchase of the residual asset by the lessee or another party. Impairment of residual values arises if the expected fair value is less than the carrying amount. The Company assesses its net investment in lease financing receivables (including residual values) for impairment on a quarterly basis with any impairment losses recognized in accordance with the impairment guidance for financial instruments. As such, net investment in lease financing receivables may be reduced by an allowance for credit losses with changes recognized as provision expense. The composition of the Company’s total net investment in lease financing receivables included within equipment financing loans in the Consolidated Statements of Condition was as follows: (in millions) September 30, 2019 Lease payments receivable $ 1,380.0 Estimated residual value of leased assets 128.4 Gross investment in lease financing receivables 1,508.4 Plus: Deferred origination costs 13.5 Less: Unearned income (154.4) Total net investment in lease financing receivables $ 1,367.5 The contractual maturities of the Company's lease financing receivables were as follows: (in millions) September 30, 2019 2019 (1) $ 229.7 2020 454.8 2021 357.7 2022 245.2 2023 137.0 Later years 84.0 Total $ 1,508.4 1. Contractual maturities for the three months remaining in 2019. Operating lease income, generated in connection with operating leases for which the Company acts as a lessor, is recognized on a straight-line basis over the lease term as a component of non-interest income in the Consolidated Statements of Income. Depreciation expense for assets under operating leases, which are included in other assets in the Consolidated Statements of Condition, is generally recorded on a straight-line basis over the lease term as a component of non-interest expense in the Consolidated Statements of Income. For the three months ended September 30, 2019, total lease income was $30.2 million, which consisted of $17.2 million from lease financing receivables and $13.0 million from operating leases. For the nine months ended September 30, 2019, total lease income was $87.6 million, which consisted of $49.2 million from lease financing receivables and $38.4 million from operating leases. Lessee Arrangements Substantially all of the Company’s lessee arrangements represent non-cancelable operating leases for real estate (primarily branch locations) and office equipment with terms extending through 2054. Under these arrangements, People's United records right-of-use ("ROU") assets and corresponding lease liabilities at lease commencement. Lease liabilities are recognized based on the present value of the remaining lease payments and discounted using the Company’s incremental borrowing rate for borrowings of similar term. ROU assets initially equal the related lease liability, adjusted for any lease payments made prior to the lease commencement and any lease incentives. Portions of certain properties are subleased for terms extending through 2024. At lease commencement, the Company considers renewal or termination options in the determination of the term of the lease. If it is reasonably certain that a renewal or termination option will be exercised, the effects of such options are included in the determination of the expected lease term. All leases are recorded with the exception of leases with an initial term of twelve months or less for which the Company made the short-term lease election. Within the Consolidated Statements of Condition, ROU assets are reported in other assets and the related lease liabilities are reported in other liabilities. In recognizing ROU assets and related lease liabilities, lease and non-lease components (such as taxes, insurance and common area maintenance costs) are accounted for separately as such amounts are generally readily determinable under the Company's lease contracts. Lease expense is recognized on a straight-line basis over the lease term and is recorded within occupancy and equipment expense in the Consolidated Statements of Income. Variable lease payments, which generally relate to the non-lease components noted above, are expensed as incurred. The following tables provide the components of lease cost and supplemental information: Three Months Ended Nine Months Ended (in millions) September 30, 2019 September 30, 2019 Operating lease cost $ 15.0 $ 45.4 Variable lease cost 2.0 6.4 Sublease income (0.3) (1.0) Net lease cost $ 16.7 $ 50.8 (dollars in millions) As of and for Nine Months Ended September 30, 2019 Lease ROU assets $ 235.6 Lease liabilities 260.5 Cash payments included in the measurement of lease liabilities reported in operating cash flows 45.8 ROU assets obtained in exchange for lessee operating lease liabilities (1) 30.3 Weighted average discount rate 3.28 % Weighted average remaining lease term (in years) 7.0 1. Amount excludes related transition adjustment (see Note 15). The contractual maturities of the Company's lease liabilities were as follows: (in millions) September 30, 2019 2019 (1) $ 15.1 2020 59.1 2021 56.7 2022 39.5 2023 28.3 Later years 102.8 Total lease payments 301.5 Less: Interest (41.0) Total lease liabilities $ 260.5 1. Contractual maturities for the three months remaining in 2019. At December 31, 2018, future minimum rental commitments under operating leases in excess of one year were: $65.4 million in 2019; $60.1 million in 2020; $56.4 million in 2021; $37.8 million in 2022; $26.1 million in 2023; and an aggregate of $88.5 million in 2024 through 2054. These amounts include variable lease payments which are excluded from the lessee maturity analysis presented above. There has been no significant change in the Company's expected future minimum lease payments since December 31, 2018.

New Accounting Standards

New Accounting Standards	9 Months Ended
New Accounting Standards	Sep. 30, 2019
Accounting Changes and Error Corrections [Abstract]
New Accounting Standards	NOTE 15. NEW ACCOUNTING STANDARDS Standards effective in 2019 Accounting for Leases In February 2016, the Financial Accounting Standards Board (the “FASB”) amended its standards with respect to the accounting for leases. The amended guidance serves to replace all current GAAP guidance on this topic and requires that an operating lease be recognized on the statement of condition as a ROU asset along with a corresponding liability representing the rent obligation. Key aspects of current lessor accounting generally remain unchanged from existing guidance, although the definition of eligible initial direct costs (“IDC”) has been amended. The guidance became effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018 (January 1, 2019 for People’s United) and, as originally issued, required the use of the modified retrospective transition approach for existing leases that have not expired before the date of initial application. In July 2018, the FASB issued two targeted improvements to the standard with the objective of reducing the cost and complexity of implementing the guidance. These amendments, which have the same effective date and transition requirements as the new lease standard, serve to (i) introduce an optional transition method allowing entities to recognize a cumulative-effect transition adjustment to the opening balance of retained earnings in the period of adoption rather than in the earliest period presented and (ii) provide a practical expedient whereby lessors can elect, by class of underlying asset, to not separate lease and related non-lease components if certain criteria are met. The Company elected the optional transition method which results in the modified retrospective approach being applied on January 1, 2019 (as opposed to January 1, 2017). The Company also elected certain transition relief options provided in the standard, including the package of practical expedients. These relief options allow the Company to forego (i) the recognition of ROU assets and lease liabilities arising from short-term leases (i.e. leases with terms of twelve months or less) and (ii) a reassessment as to: (a) whether expired or existing contracts are or contain leases; (b) the lease classification for expired or existing leases; and (c) whether previously capitalized IDC for existing leases would qualify for capitalization under the standard. The Company did not elect the hindsight practical expedient which allows entities to use hindsight when determining lease term and impairment of ROU assets. The Company identified several areas that are within the scope of the guidance, including (i) its contracts with respect to leased real estate and office equipment and (ii) lease agreements entered into with customers of the Company’s equipment financing businesses. The most significant impact of adopting the guidance relates to real estate (primarily branch locations) and office equipment subject to non-cancelable operating lease agreements entered into by the Company as lessee. The amount of the ROU assets and corresponding lease liabilities recorded upon adoption were based, primarily, on the present value of unpaid future minimum lease payments, the amount of which is dependent upon the population of leases in effect at the date of adoption, as well as assumptions with respect to renewals and/or extensions and the interest rate used to discount the future lease obligations. The Federal banking agencies have indicated that to the extent a ROU asset arises due to a lease of a tangible asset (e.g. building or equipment), the asset should be: (i) treated as a tangible asset not subject to deduction from regulatory capital; (ii) risk-weighted at 100%; and (iii) included in total assets for leverage capital purposes. As it relates to lease agreements entered into with equipment financing customers, and for which the Company acts as lessor, the impact principally relates to the definition of eligible IDC under the new guidance. Specifically, the standard maintains a narrower definition of IDC which will result in the Company recognizing immediately (rather than deferring) certain lease origination-related expenses. Such expenses would be offset by the recognition of a higher yield on the underlying leases over their contractual term. The guidance was adopted on January 1, 2019 and resulted in the recognition of (i) operating lease liabilities totaling $268.8 million, based on the present value of the remaining minimum lease payments, determined using a discount rate as of the effective date and (ii) corresponding ROU assets totaling $248.5 million, based upon the operating lease liabilities, adjusted for prepaid and deferred rent, and liabilities associated with lease termination costs. This transition adjustment served to increase risk-weighted assets, resulting in an approximate 5-10 basis point decrease in the risk-based capital ratios of both the Company and the Bank at that time. While the adoption of the guidance did not have a material impact on the Company’s Consolidated Statements of Income or Consolidated Statements of Cash Flows, the Company has, where appropriate, modified its business processes, systems and internal controls in order to support the recognition, measurement and disclosure requirements of the new standard. Expanded disclosures about the nature and terms of lease agreements, which are required prospectively, have been included in Note 14. Premium Amortization – Purchased Callable Debt Securities In April 2017, the FASB amended its standards to shorten the amortization period for certain callable debt securities held at a premium, requiring such premiums to be amortized to the earliest call date unless applicable guidance related to certain pools of securities is applied to consider estimated prepayments. Under prior guidance, entities were generally required to amortize premiums on individual, non-pooled callable debt securities as a yield adjustment over the contractual life of the security. This amendment, which does not change the accounting for callable debt securities held at a discount, became effective for People's United on January 1, 2019 and did not have a significant impact on the Company’s Consolidated Financial Statements. Derivatives and Hedging In August 2017, the FASB amended its standards with respect to the accounting for derivatives and hedging, simplifying existing guidance in order to enable companies to more accurately portray the economic effects of risk management activities in the financial statements and enhancing the transparency and understandability of hedge results through improved disclosures. This new guidance became effective on January 1, 2019 for People’s United and did not have a significant impact on the Company’s Consolidated Financial Statements. Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income In February 2018, as a result of the enactment of the Tax Cuts and Jobs Act (the “Act”), the FASB issued new accounting guidance providing entities with the option to reclassify, from accumulated other comprehensive income to retained earnings, certain “stranded tax effects” resulting from application of the Act. An entity that elects to do so must provide the following disclosures in the period of adoption: (i) that an election was made to reclassify the income tax effects of the Act from accumulated other comprehensive income to retained earnings and (ii) a description of other income tax effects related to the application of the Act that were reclassified from accumulated other comprehensive income to retained earnings, if any (e.g. income tax effects other than the effect of the change in the U.S. federal corporate income tax rate on gross deferred tax amounts and related valuation allowances). Regardless of whether an entity elects to adopt the guidance or not it is required to disclose its accounting policy for releasing income tax effects from accumulated other comprehensive income (e.g. the portfolio approach or the security-by-security approach). The guidance is effective for all organizations for fiscal years beginning after December 15, 2018 (January 1, 2019 for People’s United), including interim periods within those fiscal years, and early adoption is permitted. Entities electing to apply the guidance should do so (i) as of the beginning of the period of adoption or (ii) retrospectively to each period in which the effect of the change in the U.S. federal corporate income tax rate is recognized. The Company elected to early adopt this amendment effective January 1, 2018 (for the reporting period ending on March 31, 2018). Upon adoption, $37.9 million, representing the income tax effects of the Act as well as the indirect impacts from the decreased federal tax effect on future state tax benefits, was reclassified from AOCL to retained earnings. The reclassification adjustment, which related to: (i) the net actuarial loss on defined benefit pension and postretirement plans; (ii) the net unrealized loss on debt securities available-for-sale and debt securities transferred to held-to-maturity; and (iii) the net unrealized loss on derivatives accounted for as cash flow hedges, served to increase regulatory capital by $37.9 million, which resulted in an approximate 11 basis point increase in the risk-based capital ratios of both the Company and the Bank at that time. Standards effective in 2020 Financial Instruments – Credit Losses In June 2016, the FASB amended its standards with respect to certain aspects of measurement, recognition and disclosure of credit losses on loans and other financial instruments carried at amortized cost, as well as available-for-sale debt securities and purchased financial assets with credit deterioration (“PCD assets”). The amendment is to be applied through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective (that is, a modified-retrospective approach). For certain assets (such as debt securities for which other-than-temporary impairment has been recognized before the effective date and PCD assets), a prospective transition approach is required. For existing PCI assets, upon adoption, the amortized cost basis will be adjusted to reflect the addition of the allowance for credit losses (“ACL”). This transition relief avoids the need for a reporting entity to reassess its purchased financial assets that exist as of the date of adoption in order to determine whether they would have met, at acquisition, the new criteria of ‘more-than insignificant’ credit deterioration since origination. The transition relief also allows an entity to accrete the remaining noncredit discount (based on the revised amortized cost basis) into interest income over the life of the related asset using the interest method. For public business entities, this new amendment is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019 (January 1, 2020 for People's United) and earlier application is permitted as of the beginning of an interim or annual reporting period beginning after December 15, 2018. While early adoption is permitted, the Company has not elected that option. To assist in implementing the standard, the Company has formed a cross-functional working group, comprised of individuals from various disciplines, including credit, risk management, information technology and finance. The implementation activities of the working group are subject to the Company’s established corporate governance and oversight structure. To date, the working group has: (i) purchased and installed a third-party vendor solution to aid in application of the standard; (ii) established the Company’s portfolio segmentation; (iii) fulfilled historical data requirements necessary to comply with the standard; and (iv) developed and tested loss estimation models leveraged from existing credit models used to comply with other regulatory requirements. Currently, the working group continues to monitor emerging interpretative guidance issued by standard setters while also finalizing and documenting the relevant processes, systems, internal controls and data sources necessary to support the requirements of the new standard, including related disclosures. For the remainder of 2019, the Company plans to further test, refine and validate its loss estimation framework during continued parallel runs that involve a comprehensive assessment of: (i) model functionality; (ii) internal control design and effectiveness; and (iii) related governance activities. Under the standard, the ACL will be determined based on the Company’s historical loss experience, current borrower-specific risk characteristics, forecasts of future economic conditions and other relevant factors. The Company anticipates utilizing a two-year reasonable and supportable forecast period followed by a one-year period over which estimated losses revert to historical loss experience for the remaining life of the loan. As a result of the required change to determining estimated credit losses from the current “incurred loss” model to a “life of loan” model, the Company expects the new guidance will result in an increase in the allowance for loan losses, particularly for longer duration portfolios. At this time, based upon forecasted economic conditions and portfolio balances existing as of September 30, 2019, adoption of the standard could result in an overall inc rease of 15%-25%, or approximately $40-$60 million (pre-tax), as compared to the Company’s current aggregate allowance levels. The increase is driven, primarily, by higher reserve requirements associated with the Company’s retail portfolios (i.e. residential mortgage and home equity) due to the difference between the loss emergence periods currently used for these portfolios under the incurred loss model and the expected remaining life of such loans as required by the standard, partially offset by lower reserve requirements associated with certain of the Company’s commercial portfolios which generally have shorter contractual maturities. While the Company also expects the new guidance may result in an allowance for held-to-maturity debt securities measured at amortized cost, it is not expected that such allowance will be material as the portfolio consists primarily of agency-backed securities and highly-rated municipal and corporate bonds, all of which inherently have minimal non-payment risk. The Company’s credit loss models remain subject to further development and refinement. Accordingly, the extent of the Company’s estimate of expected credit losses will be dependent upon portfolio size, composition and credit quality at the adoption date, as well as economic conditions and forecasts at that time. Further, in light of the November 1, 2019 merger with United Financial Bancorp, Inc. (“United Financial”) (see Note 16), the Company has not yet evaluated the impact of the merger on its implementation effort to ensure that its consolidated estimate of impact gives appropriate consideration to the acquired entity. In December 2018, the Federal banking agencies issued a final rule with respect to how the impact of the amended standard is to be treated for regulatory capital purposes. That rule serves to revise the regulatory capital rules to, among other things, provide banks an option to phase-in, over three years, the day-one regulatory capital effects of the standard. Based upon the September 30, 2019 estimated impact noted above, capital ratios for both the Bank and the Holding Company could decre ase by 10-15 basis point s. Simplifying the Test for Goodwill Impairment In January 2017, the FASB amended its standards with respect to goodwill, simplifying how an entity is required to conduct the impairment assessment by eliminating Step 2, which requires a hypothetical purchase price allocation, from the goodwill impairment test. Instead, goodwill impairment will now be measured as the amount by which a reporting unit’s carrying amount exceeds its fair value, not to exceed the carrying amount of goodwill. An entity will still have the option to perform a qualitative assessment to determine if a quantitative impairment test is necessary. For public business entities, this new guidance is effective in fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019 (January 1, 2020 for People’s United) and is to be applied prospectively. Early adoption is permitted for any impairment tests performed after January 1, 2017. This amendment, which the Company elected to early adopt effective January 1, 2018, did not have a significant impact on the Company’s Consolidated Financial Statements. Disclosure Requirements – Fair Value Measurement In August 2018, the FASB issued targeted amendments that serve to eliminate, add and modify certain disclosure requirements for fair value measurements. Among the changes, entities are no longer required to disclose the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, but are required to disclose the range and weighted average used to develop significant unobservable inputs for Level 3 fair value measurements. These amendments are effective for interim and annual reporting periods beginning after December 15, 2019 (January 1, 2020 for People’s United) and early adoption is permitted. Entities may also elect to (i) early adopt the eliminated and/or modified disclosure requirements and (ii) delay adoption of the new disclosure requirements until their effective date. The provisions set forth in this guidance, which the Company elected to early adopt in 2018, have been reflected in Note 11 (as applicable) and did not have a significant impact on the Company’s Consolidated Financial Statements. Standards effective in 2021 Disclosure Requirements – Defined Benefit Plans In August 2018, the FASB issued targeted amendments that serve to make minor changes to the disclosure requirements for employers that sponsor defined benefit pension and/or other postretirement benefit plans. More specifically, the amendments (i) remove disclosures that are no longer considered cost beneficial; (ii) clarify the specific requirements of selected disclosures; and (iii) add disclosure requirements identified as relevant. These amendments are effective for fiscal years ending after December 15, 2020 (January 1, 2021 for People’s United) and early adoption is permitted. The provisions set forth in this guidance, which the Company elected to early adopt in 2018, have been reflected in Note 8 (as applicable) and did not have a significant impact on the Company’s Consolidated Financial Statements.

Subsequent Events

Subsequent Events	9 Months Ended
Subsequent Events	Sep. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	NOTE 16. SUBSEQUENT EVENTS Sale of Branches On October 25, 2019, the Bank completed the sale of eight branches located in central Maine, including approximately: (i) $104 million in loans; (ii) $262 million in deposits; and (iii) $240 million of assets under management. The sale is expected to result in a gain, net of expenses, of approximately $9 to $10 million. Completed A cquisition Effective November 1, 2019, People’s United completed its acquisition of United Financial based in Hartford, Connecticut. Accordingly, People’s United’s consolidated financial statements as of and for the periods ended September 30, 2019 do not include amounts for United Financial. At September 30, 2019, United Financial reported total loans of $5.7 billion and total deposits of $5.7 billion, and operated 59 branch locations concentrated in central Connecticut and western Massachusetts. The fair value of the consideration transferred in the United Financial acquisition totaled $723.6 million and consisted of 44.7 million shares of People’s United common stock. Merger-related expenses totaling $1.0 million relating to this transaction were recorded in the nine months ended September 30, 2019.

Employee Benefit Plans (Policie

Employee Benefit Plans (Policies)	9 Months Ended
Employee Benefit Plans (Policies)	Sep. 30, 2019
People's United Employee Pension and Other Postretirement Plans	People’s United Employee Pension and Other Postretirement Plans People’s United maintains a qualified noncontributory defined benefit pension plan (the “People’s Qualified Plan”) that covers substantially all full-time and part-time employees who (i) meet certain age and length of service requirements and (ii) were employed by the Bank prior to August 14, 2006. Benefits are based upon the employee’s years of credited service and either the average compensation for the last five years or the average compensation for the five New employees of the Bank starting on or after August 14, 2006 are not eligible to participate in the People’s Qualified Plan. Instead, the Bank makes contributions on behalf of these employees to a qualified defined contribution plan in an annual amount equal to 3% of the employee’s eligible compensation. Employee participation in this plan is restricted to employees who (i) are at least 18 years of age and (ii) worked at least 1,000 hours in a year. Both full-time and part-time employees are eligible to participate as long as they meet these requirements. In July 2011, the Bank amended the People’s Qualified Plan to “freeze”, effective December 31, 2011, the accrual of pension benefits for People’s Qualified Plan participants. As such, participants will not earn any additional benefits after that date. Instead, effective January 1, 2012, the Bank began making contributions on behalf of these participants to a qualified defined contribution plan in an annual amount equal to 3% of the employee’s eligible compensation. In addition to the People’s Qualified Plan, People’s United continues to maintain a qualified defined benefit pension plan that covers former First Connecticut Bancorp, Inc. ("First Connecticut") employees who meet certain eligibility requirements (the “First Connecticut Qualified Plan”). All benefits under this plan were frozen effective February 28, 2013. People’s United’s funding policy is to contribute the amounts required by applicable regulations, although additional amounts may be contributed from time to time.
Employee Stock Ownership Plan	Employee Stock Ownership Plan In April 2007, People’s United established an ESOP. At that time, People’s United loaned the ESOP $216.8 million to purchase 10,453,575 shares of People’s United common stock in the open market. In order for the ESOP to repay the loan, People’s United expects to make annual cash contributions of approximately $18.8 million until 2036. Such cash contributions may be reduced by the cash dividends paid on unallocated ESOP shares, which, for the nine months ended September 30, 2019, totaled $3.3 million. At September 30, 2019, the loan balance totaled $176.5 million. Employee participation in this plan is restricted to those employees who (i) are at least 18 years of age and (ii) worked at least 1,000 hours within 12 months of their hire date or any plan year (January 1 to December 31) after their date of hire. Employees meeting the aforementioned eligibility criteria during the plan year must continue to be employed as of the last day of the plan year in order to receive an allocation of shares for that plan year. Shares of People’s United common stock are held by the ESOP and allocated to eligible participants annually based upon a percentage of each participant’s eligible compensation. Since the ESOP was established, a total of 4,442,769 shares of People’s United common stock have been allocated or committed to be released to participants’ accounts. At September 30, 2019, 6,010,806 shares of People’s United common stock, with a fair value of $94.0 million at that date, have not been allocated or committed to be released. Compensation expense related to the ESOP is recognized at an amount equal to the number of common shares committed to be released by the ESOP for allocation to participants’ accounts multiplied by the average fair value of People’s United’s common stock during the reporting period. The difference between the fair value of the shares of People’s United’s common stock committed to be released and the cost of those common shares is recorded as a credit to additional paid-in capital (if fair value exceeds cost) or, to the extent that no such credits remain in additional paid-in capital, as a charge to retained earnings (if fair value is less than cost). Expense recognized for the ESOP totaled $4.2 million and $4.8 million for the nine months ended September 30, 2019 and 2018, respectively.
Recurring
Fair Value Measurements	Recurring Fair Value Measurements Trading Debt Securities, Equity Securities and Debt Securities Available-For-Sale When available, People’s United uses quoted market prices for identical securities received from an independent, nationally-recognized, third-party pricing service (as discussed further below) to determine the fair value of investment securities such as U.S. Treasury and agency securities and equity securities that are included in Level 1. When quoted market prices for identical securities are unavailable, People’s United uses prices provided by the independent pricing service based on recent trading activity and other observable information including, but not limited to, market interest rate curves, referenced credit spreads and estimated prepayment rates where applicable. These investments include certain U.S. and government agency debt securities, corporate and municipal debt securities, and GSE mortgage-backed securities, all of which are included in Level 2. The Company’s available-for-sale debt securities are primarily comprised of GSE mortgage-backed securities. The fair value of these securities is based on prices obtained from the independent pricing service. The pricing service uses various techniques to determine pricing for the Company’s mortgage-backed securities, including option pricing and discounted cash flow analysis. The inputs include benchmark yields, reported trades, broker/dealer quotes, issuer spreads, benchmark securities, bids, offers, reference data, monthly payment information and collateral performance. At both September 30, 2019 and December 31, 2018, the entire available-for-sale mortgage-backed securities portfolio was comprised of 10- and 15-year GSE securities. An active market exists for securities that are similar to the Company’s GSE mortgage-backed securities, making observable inputs readily available.
Nonrecurring
Fair Value Measurements	Non-Recurring Fair Value Measurements Loans Held-for-Sale Residential mortgage loans held-for-sale are recorded at the lower of cost or fair value and are therefore measured at fair value on a non-recurring basis. When available, People’s United uses observable secondary market data, including pricing on recent closed market transactions for loans with similar characteristics. Accordingly, such loans are classified as Level 2 measurements. When observable data is unavailable, valuation methodologies using current market interest rate data adjusted for inherent credit risk are used, and such loans are included in Level 3. Impaired Loans Loan impairment is deemed to exist when full repayment of principal and interest according to the contractual terms of the loan is no longer probable. Impaired loans are reported based on one of three measures: (i) the present value of expected future cash flows discounted at the loan’s original effective interest rate; (ii) the loan’s observable market price; or (iii) the fair value of the collateral (less estimated cost to sell) if the loan is collateral dependent. Accordingly, certain impaired loans may be subject to measurement at fair value on a non-recurring basis. People’s United has estimated the fair values of these assets using Level 3 inputs, such as discounted cash flows based on inputs that are largely unobservable and, instead, reflect management’s own estimates of the assumptions a market participant would use in pricing such loans and/or the fair value of collateral based on independent third-party appraisals for collateral-dependent loans. Such appraisals are based on the market and/or income approach to value and are subject to a discount (to reflect estimated cost to sell) that generally approximates 10%. REO and Repossessed Assets REO and repossessed assets are recorded at the lower of cost or fair value, less estimated selling costs, and are therefore measured at fair value on a non-recurring basis. People’s United has estimated the fair values of these assets using Level 3 inputs, such as independent third-party appraisals and price opinions. Such appraisals are based on the market and/or income approach to value and are subject to a discount (to reflect estimated cost to sell) that generally approximates 10%. Assets that are acquired through loan default are recorded as held-for-sale initially at the lower of the recorded investment in the loan or fair value (less estimated selling costs) upon the date of foreclosure/repossession. Subsequent to foreclosure/repossession, valuations are updated periodically and the carrying amounts of these assets may be reduced further.

Acquisitions (Tables)

Acquisitions (Tables)	9 Months Ended
Acquisitions (Tables)	Sep. 30, 2019
Business Combinations [Abstract]
Schedule of Estimated Fair Values of the Assets Acquired and Liabilities Assumed	The acquisition-date estimated fair values of the assets acquired and liabilities assumed in the acquisition of BSB Bancorp are s ummarized as follows: (in millions) Assets: Cash and cash equivalents $ 108.7 Securities 175.8 Loans 2,642.9 Goodwill 144.9 Core deposit intangible 39.5 Premises and equipment 8.3 Bank-owned life insurance 36.8 Other assets 29.8 Total assets $ 3,186.7 Liabilities: Deposits $ 2,118.7 Borrowings 696.6 Other liabilities 46.9 Total liabilities $ 2,862.2 Total purchase price $ 324.5
Schedule of Unaudited Pro Forma Financial Information	The following table presents selected unaudited pro forma financial information of the Company reflecting the acquisition of BSB Bancorp assuming the acquisition was completed as of the beginning of the respective periods: Nine Months Ended (in millions, except per common share data) 2019 2018 Selected Financial Results: Net interest income $ 1,044.7 $ 949.1 Provision for loan losses 21.0 20.1 Non-interest income 308.2 281.3 Non-interest expense 837.5 756.7 Net income 395.5 355.6 Net income applicable to common shareholders 385.0 345.1 Earnings per common share: Basic $ 0.98 $ 0.96 Diluted 0.98 0.95

Cash and Cash Equivalents and_2

Cash and Cash Equivalents and Securities (Tables)	9 Months Ended
Cash and Cash Equivalents and Securities (Tables)	Sep. 30, 2019
Cash and Cash Equivalents [Abstract]
Available-for-Sale and Held-to-Maturity Debt Securities Gains (Losses)	The amortized cost, gross unrealized gains and losses, and fair value of People’s United’s debt securities available-for-sale and debt securities held-to-maturity are as follows: As of September 30, 2019 (in millions) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Debt securities available-for-sale: U.S. Treasury and agency $ 690.6 $ 0.4 $ (2.9) $ 688.1 GSE (1) mortgage-backed securities 2,269.7 24.3 (3.4) 2,290.6 Total debt securities available-for-sale $ 2,960.3 $ 24.7 $ (6.3) $ 2,978.7 Debt securities held-to-maturity: State and municipal $ 2,432.3 $ 148.3 $ (0.3) $ 2,580.3 GSE mortgage-backed securities 1,291.7 17.0 (0.1) 1,308.6 Corporate 79.9 1.4 (0.2) 81.1 Other 1.5 — — 1.5 Total debt securities held-to-maturity $ 3,805.4 $ 166.7 $ (0.6) $ 3,971.5 1. Government sponsored enterprise As of December 31, 2018 (in millions) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Debt securities available-for-sale: U.S. Treasury and agency $ 699.0 $ 0.1 $ (21.1) $ 678.0 GSE mortgage-backed securities 2,486.6 4.6 (48.2) 2,443.0 Total debt securities available-for-sale $ 3,185.6 $ 4.7 $ (69.3) $ 3,121.0 Debt securities held-to-maturity: State and municipal $ 2,352.4 $ 35.4 $ (18.4) $ 2,369.4 GSE mortgage-backed securities 1,367.5 — (33.2) 1,334.3 Corporate 70.9 0.5 (0.7) 70.7 Other 1.5 — — 1.5 Total debt securities held-to-maturity $ 3,792.3 $ 35.9 $ (52.3) $ 3,775.9
Summary of Amortized Cost and Fair Value of Debt Securities Based on Remaining Period to Contractual Maturity	The following table is a summary of the amortized cost and fair value of debt securities as of September 30, 2019, based on remaining period to contractual maturity. Information for GSE mortgage-backed securities is based on the final contractual maturity dates without considering repayments and prepayments. Available-for-Sale Held-to-Maturity (in millions) Amortized Cost Fair Value Amortized Cost Fair Value U.S. Treasury and agency: Within 1 year $ 158.9 $ 158.9 $ — $ — After 1 but within 5 years 531.7 529.2 — — Total 690.6 688.1 — — GSE mortgage-backed securities: Within 1 year — — 2.8 2.8 After 1 but within 5 years 95.4 97.7 766.4 778.9 After 5 but within 10 years 714.9 730.6 217.0 221.3 After 10 years 1,459.4 1,462.3 305.5 305.6 Total 2,269.7 2,290.6 1,291.7 1,308.6 State and municipal: Within 1 year — — 12.0 12.0 After 1 but within 5 years — — 213.1 221.5 After 5 but within 10 years — — 406.0 430.7 After 10 years — — 1,801.2 1,916.1 Total — — 2,432.3 2,580.3 Corporate: Within 1 year — — 5.0 5.0 After 5 but within 10 years — — 74.9 76.1 Total — — 79.9 81.1 Other: Within 1 year — — 1.5 1.5 Total — — 1.5 1.5 Total: Within 1 year 158.9 158.9 21.3 21.3 After 1 but within 5 years 627.1 626.9 979.5 1,000.4 After 5 but within 10 years 714.9 730.6 697.9 728.1 After 10 years 1,459.4 1,462.3 2,106.7 2,221.7 Total $ 2,960.3 $ 2,978.7 $ 3,805.4 $ 3,971.5
Continuous Unrealized Loss Position on Available-for-Sale and Held-to-Maturity Securities	The following tables summarize those debt securities with unrealized losses, segregated by the length of time the securities have been in a continuous unrealized loss position, at the respective dates. Certain unrealized losses totaled less than $0.1 million. Continuous Unrealized Loss Position Less Than 12 Months 12 Months Or Longer Total As of September 30, 2019 (in millions) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Debt securities available-for-sale: GSE mortgage-backed securities $ 201.2 $ (0.4) $ 700.0 $ (3.1) $ 901.2 $ (3.5) U.S. Treasury and agency 105.3 (0.2) 463.1 (2.6) 568.4 (2.8) Total debt securities available-for-sale $ 306.5 $ (0.6) $ 1,163.1 $ (5.7) $ 1,469.6 $ (6.3) Debt securities held-to-maturity: GSE mortgage-backed securities $ 110.4 $ (0.1) $ 9.5 $ — $ 119.9 $ (0.1) State and municipal 15.6 (0.1) 12.0 (0.2) 27.6 (0.3) Corporate — — 8.4 (0.2) 8.4 (0.2) Total debt securities held-to-maturity $ 126.0 $ (0.2) $ 29.9 $ (0.4) $ 155.9 $ (0.6) Continuous Unrealized Loss Position Less Than 12 Months 12 Months Or Longer Total As of December 31, 2018 (in millions) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Debt securities available-for-sale: GSE mortgage-backed securities $ 132.4 $ (0.5) $ 1,656.3 $ (47.7) $ 1,788.7 $ (48.2) U.S. Treasury and agency — — 656.2 (21.1) 656.2 (21.1) Total debt securities available-for-sale $ 132.4 $ (0.5) $ 2,312.5 $ (68.8) $ 2,444.9 $ (69.3) Debt securities held-to-maturity: GSE mortgage-backed securities $ — $ — $ 1,334.3 $ (33.2) $ 1,334.3 $ (33.2) State and municipal 113.4 (0.7) 697.6 (17.7) 811.0 (18.4) Corporate 31.2 (0.6) 2.7 (0.1) 33.9 (0.7) Total debt securities held-to-maturity $ 144.6 $ (1.3) $ 2,034.6 $ (51.0) $ 2,179.2 $ (52.3)

Loans (Tables)

Loans (Tables)	9 Months Ended
Loans (Tables)	Sep. 30, 2019
Receivables [Abstract]
Summary of Loans by Loan Portfolio Segment and Class	The following table summarizes People’s United’s loans by loan portfolio segment and class: September 30, 2019 December 31, 2018 (in millions) Originated Acquired Total Originated Acquired Total Commercial: Commercial real estate $ 9,721.4 $ 2,465.5 $ 12,186.9 $ 9,798.5 $ 1,851.1 $ 11,649.6 Commercial and industrial 9,720.1 825.8 10,545.9 8,292.3 796.6 9,088.9 Equipment financing 4,484.5 251.1 4,735.6 3,937.7 401.5 4,339.2 Total Commercial Portfolio 23,926.0 3,542.4 27,468.4 22,028.5 3,049.2 25,077.7 Retail: Residential mortgage: Adjustable-rate 5,547.9 1,368.5 6,916.4 5,854.1 807.9 6,662.0 Fixed-rate 1,113.8 1,278.5 2,392.3 935.1 557.1 1,492.2 Total residential mortgage 6,661.7 2,647.0 9,308.7 6,789.2 1,365.0 8,154.2 Home equity and other consumer: Home equity 1,685.7 271.2 1,956.9 1,789.5 173.0 1,962.5 Other consumer 39.3 8.1 47.4 42.8 4.2 47.0 Total home equity and other consumer 1,725.0 279.3 2,004.3 1,832.3 177.2 2,009.5 Total Retail Portfolio 8,386.7 2,926.3 11,313.0 8,621.5 1,542.2 10,163.7 Total loans $ 32,312.7 $ 6,468.7 $ 38,781.4 $ 30,650.0 $ 4,591.4 $ 35,241.4
Summary, by Loan Portfolio Segment, of Activity in Allowance for Loan Losses	The following tables present a summary, by loan portfolio segment, of activity in the allowance for loan losses for the three and nine months ended September 30, 2019 and 2018. With respect to the originated portfolio, an allocation of a portion of the allowance to one segment does not preclude its availability to absorb losses in another segment. Three months ended Commercial Retail September 30, 2019 (in millions) Originated Acquired Total Originated Acquired Total Total Balance at beginning of period $ 210.9 $ 3.7 $ 214.6 $ 29.2 $ 0.2 $ 29.4 $ 244.0 Charge-offs (6.1) (1.4) (7.5) (0.7) — (0.7) (8.2) Recoveries 1.6 0.3 1.9 0.5 — 0.5 2.4 Net loan charge-offs (4.5) (1.1) (5.6) (0.2) — (0.2) (5.8) Provision for loan losses 6.9 0.9 7.8 — — — 7.8 Balance at end of period $ 213.3 $ 3.5 $ 216.8 $ 29.0 $ 0.2 $ 29.2 $ 246.0 Nine months ended Commercial Retail September 30, 2019 (in millions) Originated Acquired Total Originated Acquired Total Total Balance at beginning of period $ 205.6 $ 3.9 $ 209.5 $ 30.7 $ 0.2 $ 30.9 $ 240.4 Charge-offs (13.9) (6.2) (20.1) (2.9) — (2.9) (23.0) Recoveries 4.2 1.1 5.3 2.3 — 2.3 7.6 Net loan charge-offs (9.7) (5.1) (14.8) (0.6) — (0.6) (15.4) Provision for loan losses 17.4 4.7 22.1 (1.1) — (1.1) 21.0 Balance at end of period $ 213.3 $ 3.5 $ 216.8 $ 29.0 $ 0.2 $ 29.2 $ 246.0 Three months ended Commercial Retail September 30, 2018 (in millions) Originated Acquired Total Originated Acquired Total Total Balance at beginning of period $ 202.0 $ 3.8 $ 205.8 $ 30.8 $ 0.2 $ 31.0 $ 236.8 Charge-offs (5.7) (2.0) (7.7) (0.7) — (0.7) (8.4) Recoveries 0.6 0.4 1.0 0.4 — 0.4 1.4 Net loan charge-offs (5.1) (1.6) (6.7) (0.3) — (0.3) (7.0) Provision for loan losses 6.3 1.7 8.0 0.2 — 0.2 8.2 Balance at end of period $ 203.2 $ 3.9 $ 207.1 $ 30.7 $ 0.2 $ 30.9 $ 238.0 Nine months ended Commercial Retail September 30, 2018 (in millions) Originated Acquired Total Originated Acquired Total Total Balance at beginning of period $ 201.1 $ 3.4 $ 204.5 $ 29.7 $ 0.2 $ 29.9 $ 234.4 Charge-offs (12.9) (6.3) (19.2) (2.6) — (2.6) (21.8) Recoveries 2.6 1.0 3.6 1.7 — 1.7 5.3 Net loan charge-offs (10.3) (5.3) (15.6) (0.9) — (0.9) (16.5) Provision for loan losses 12.4 5.8 18.2 1.9 — 1.9 20.1 Balance at end of period $ 203.2 $ 3.9 $ 207.1 $ 30.7 $ 0.2 $ 30.9 $ 238.0
Summary of Allowance for Loan Losses by Loan Portfolio Segment and Impairment Methodology	The following tables summarize, by loan portfolio segment and impairment methodology, the allowance for loan losses and related portfolio balances: Commercial Retail Total As of September 30, 2019 (in millions) Portfolio Allowance Portfolio Allowance Portfolio Allowance Originated loans: Collectively evaluated for impairment $ 22,258.6 $ 206.0 $ 9,850.9 $ 26.9 $ 32,109.5 $ 232.9 Individually evaluated for impairment 112.7 7.3 90.6 2.1 203.3 9.4 Acquired loans: PCI (1) 219.0 2.2 72.2 0.2 291.2 2.4 Purchased performing: Collectively evaluated for impairment 4,870.5 1.3 1,292.4 — 6,162.9 1.3 Individually evaluated for impairment 7.6 — 6.9 — 14.5 — Total $ 27,468.4 $ 216.8 $ 11,313.0 $ 29.2 $ 38,781.4 $ 246.0 Commercial Retail Total As of December 31, 2018 (in millions) Portfolio Allowance Portfolio Allowance Portfolio Allowance Originated loans: Collectively evaluated for impairment $ 21,900.1 $ 198.9 $ 8,535.0 $ 28.4 $ 30,435.1 $ 227.3 Individually evaluated for impairment 128.4 6.7 86.5 2.3 214.9 9.0 Acquired loans: PCI (1) 300.3 2.2 99.6 0.1 399.9 2.3 Purchased performing: Collectively evaluated for impairment 2,744.4 1.7 1,439.1 — 4,183.5 1.7 Individually evaluated for impairment 4.5 — 3.5 0.1 8.0 0.1 Total $ 25,077.7 $ 209.5 $ 10,163.7 $ 30.9 $ 35,241.4 $ 240.4 1. Purchased credit impaired (“PCI”) loans are evaluated for impairment on a pool basis.
Summarized Recorded Investments, by Class of Loan, in Originated Non-Performing Loans	The recorded investments, by class of loan, in originated non-performing loans are summarized as follows: September 30, December 31, (in millions) Commercial: Commercial real estate $ 25.1 $ 33.5 Commercial and industrial 37.7 38.0 Equipment financing 41.5 42.0 Total (1) 104.3 113.5 Retail: Residential mortgage 36.6 38.9 Home equity 14.3 15.3 Other consumer 0.1 — Total (2) 51.0 54.2 Total $ 155.3 $ 167.7 1. Reported net of government guarantees totaling $1.4 million and $1.9 million at September 30, 2019 and December 31, 2018, respectively. These government guarantees relate, almost entirely, to guarantees provided by the Small Business Administration as well as selected other Federal agencies and represent the carrying value of the loans that are covered by such guarantees, the extent of which (i.e. full or partial) varies by loan. At September 30, 2019, the principal loan classes to which these government guarantees relate are commercial and industrial loans (95%) and commercial real estate loans (5%). 2. Includes $22.1 million and $24.8 million of loans in the process of foreclosure at September 30, 2019 and December 31, 2018, respectively.
Summary of Recorded Investments in TDRs by Class of Loan	The following tables summarize, by class of loan, the recorded investments in loans modified as TDRs during the three and nine months ended September 30, 2019 and 2018. For purposes of this disclosure, recorded investments represent amounts immediately prior to and subsequent to the restructuring. Three Months Ended September 30, 2019 (dollars in millions) Number of Contracts Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Commercial: Commercial real estate (1) 7 $ 13.1 $ 13.1 Commercial and industrial (2) 8 4.1 4.1 Equipment financing (3) 10 9.5 9.5 Total 25 26.7 26.7 Retail: Residential mortgage (4) 15 6.5 6.5 Home equity (5) 15 1.3 1.3 Other consumer — — — Total 30 7.8 7.8 Total 55 $ 34.5 $ 34.5 1. Represents the following concessions: extension of term (5 contracts; recorded investment of $1.7 million); or a combination of concessions (2 contracts; recorded investment of $11.4 million). 2. Represents the following concessions: extension of term (5 contracts; recorded investment of $1.9 million); reduced payment and/or payment deferral (2 contracts; recorded investment of $0.3 million); or a combination of concessions (1 contract; recorded investment of $1.9 million). 3. Represents the following concessions: extension of term (1 contract; recorded investment of $0.4 million); reduced payment and/or payment deferral (5 contracts; recorded investment of $5.1 million); or a combination of concessions (4 contracts; recorded investment of $4.0 million). 4. Represents the following concessions: loans restructured through bankruptcy (4 contracts; recorded investment of $1.6 million); reduced payment and/or payment deferral (9 contracts; recorded investment of $3.7 million); or a combination of concessions (2 contracts; recorded investment of $1.2 million). 5. Represents the following concessions: loans restructured through bankruptcy (6 contracts; recorded investment of $0.4 million); reduced payment and/or payment deferral (5 contracts; recorded investment of $0.6 million); or a combination of concessions (4 contracts; recorded investment of $0.3 million). Nine Months Ended September 30, 2019 (dollars in millions) Number Pre-Modification Post-Modification Commercial: Commercial real estate (1) 8 $ 13.7 $ 13.7 Commercial and industrial (2) 27 27.5 27.5 Equipment financing (3) 33 22.9 22.9 Total 68 64.1 64.1 Retail: Residential mortgage (4) 73 22.2 22.2 Home equity (5) 83 7.0 7.0 Other consumer — — — Total 156 29.2 29.2 Total 224 $ 93.3 $ 93.3 1. Represents the following concessions: extension of term (5 contracts; recorded investment of $1.7 million); reduced payment and/or payment deferral (1 contract; recorded investment of $0.6 million); or a combination of concessions (2 contracts; recorded investment of $11.4 million). 2. Represents the following concessions: extension of term (22 contracts; recorded investment of $24.3 million); reduced payment and/or payment deferral (2 contracts; recorded investment of $0.3 million); or a combination of concessions (3 contracts; recorded investment of $2.9 million). 3. Represents the following concessions: extension of term (5 contracts; recorded investment of $1.6 million); reduced payment and/or payment deferral (22 contracts; recorded investment of $16.9 million); or a combination of concessions (6 contracts; recorded investment of $4.4 million). 4. Represents the following concessions: loans restructured through bankruptcy (39 contracts; recorded investment of $8.2 million); reduced payment and/or payment deferral (21 contracts; recorded investment of $8.4 million); or a combination of concessions (13 contracts; recorded investment of $5.6 million). 5. Represents the following concessions: loans restructured through bankruptcy (48 contracts; recorded investment of $2.6 million); reduced payment and/or payment deferral (16 contracts; recorded investment of $2.8 million); or a combination of concessions (19 contracts; recorded investment of $1.6 million). Three Months Ended September 30, 2018 (dollars in millions) Number of Contracts Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Commercial: Commercial real estate (1) 4 $ 20.7 $ 20.7 Commercial and industrial (2) 10 10.3 10.3 Equipment financing (3) 5 10.3 10.3 Total 19 41.3 41.3 Retail: Residential mortgage (4) 4 1.4 1.4 Home equity (5) 19 2.2 2.2 Other consumer — — — Total 23 3.6 3.6 Total 42 $ 44.9 $ 44.9 1. Represents the following concession: extension of term (3 contracts; recorded investment of $20.2 million); or reduced payment and/or payment deferral (1 contract; recorded investment of $0.5 million). 2. Represents the following concessions: extension of term (6 contracts; recorded investment of $3.6 million); reduced payment and/or payment deferral (2 contracts; recorded investment of $6.4 million); or a combination of concessions (2 contracts; recorded investment of $0.3 million). 3. Represents the following concessions: extension of term (2 contracts; recorded investment of $3.3 million); reduced payment and/or payment deferral (2 contracts; recorded investment of $5.9 million); a combination of concessions (1 contract; recorded investment of $1.1 million). 4. Represents the following concessions: loans restructured through bankruptcy (2 contracts; recorded investment of $0.6 million); reduced payment and/or payment deferral (1 contract; recorded investment of $0.7 million); or a combination of concessions (1 contract; recorded investment of $0.1 million). 5. Represents the following concessions: loans restructured through bankruptcy (11 contracts; recorded investment of $1.1 million); reduced payment and/or payment deferral (6 contracts; recorded investment of $1.0 million); or a combination of concessions (2 contracts; recorded investment of $0.1 million). Nine Months Ended September 30, 2018 (dollars in millions) Number Pre-Modification Post-Modification Commercial: Commercial real estate (1) 9 $ 24.3 $ 24.3 Commercial and industrial (2) 34 55.2 55.2 Equipment financing (3) 16 20.4 20.4 Total 59 99.9 99.9 Retail: Residential mortgage (4) 16 4.9 4.9 Home equity (5) 56 4.9 4.9 Other consumer — — — Total 72 9.8 9.8 Total 131 $ 109.7 $ 109.7 1. Represents the following concessions: extension of term (8 contracts; recorded investment of $23.8 million); or reduced payment and/or payment deferral (1 contract; recorded investment of $0.5 million). 2. Represents the following concessions: extension of term (21 contracts; recorded investment of $30.7 million); reduced payment and/or payment deferral (10 contracts; recorded investment of $23.8 million); or a combination of concessions (3 contracts; recorded investment of $0.7 million). 3. Represents the following concessions: extension of term (2 contracts; recorded investment of $3.3 million): reduced payment and/or payment deferral (8 contracts; recorded investment of $12.9 million); or a combination of concessions (6 contracts; recorded investment of $4.2 million). 4. Represents the following concessions: loans restructured through bankruptcy (5 contracts; recorded investment of $0.9 million); reduced payment and/or payment deferral (6 contracts; recorded investment of $2.4 million); or a combination of concessions (5 contracts; recorded investment of $1.6 million). 5. Represents the following concessions: loans restructured through bankruptcy (37 contracts; recorded investment of $2.8 million); reduced payment and/or payment deferral (10 contracts; recorded investment of $1.3 million); or a combination of concessions (9 contracts; recorded investment of $0.8 million).
Summary of Recorded Investments in TDRs by Class of Loan, Subsequently Defaulted	The following is a summary, by class of loan, of information related to TDRs completed within the previous 12 months that subsequently defaulted during the three and nine months ended September 30, 2019 and 2018. For purposes of this disclosure, the previous 12 months is measured from October 1 of the respective prior year and a default represents a previously-modified loan that became past due 30 days or more during the three or nine months ended September 30, 2019 or 2018. Three Months Ended September 30, 2019 2018 (dollars in millions) Number of Contracts Recorded Investment as of Period End Number of Contracts Recorded Investment as of Period End Commercial: Commercial real estate 1 $ 0.2 — $ — Commercial and industrial — — 4 5.0 Equipment financing 1 0.3 1 0.2 Total 2 0.5 5 5.2 Retail: Residential mortgage 2 0.6 5 0.9 Home equity 3 0.1 8 0.6 Other consumer — — — — Total 5 0.7 13 1.5 Total 7 $ 1.2 18 $ 6.7 Nine Months Ended September 30, 2019 2018 (dollars in millions) Number Recorded Number Recorded Commercial: Commercial real estate 1 $ 0.2 2 $ 0.8 Commercial and industrial — — 13 8.5 Equipment financing 8 8.2 7 6.8 Total 9 8.4 22 16.1 Retail: Residential mortgage 6 2.4 7 1.3 Home equity 9 0.6 9 0.6 Other consumer — — — — Total 15 3.0 16 1.9 Total 24 $ 11.4 38 $ 18.0
Summary of Individually-Evaluated Impaired Loans by Class of Loan	People’s United’s impaired loans consist of certain loans that have been placed on non-accrual status, including all TDRs. The following table summarizes, by class of loan, information related to individually-evaluated impaired loans. As of September 30, 2019 As of December 31, 2018 (in millions) Unpaid Principal Balance Recorded Investment Related Allowance for Loan Losses Unpaid Principal Balance Recorded Investment Related Allowance for Loan Losses Without a related allowance for loan losses: Commercial: Commercial real estate $ 38.9 $ 35.7 $ — $ 31.0 $ 28.1 $ — Commercial and industrial 34.9 29.9 — 45.6 42.0 — Equipment financing 21.2 19.2 — 20.2 18.0 — Retail: Residential mortgage 69.1 61.4 — 66.8 59.3 — Home equity 26.5 23.2 — 23.8 20.3 — Other consumer — — — — — — Total $ 190.6 $ 169.4 $ — $ 187.4 $ 167.7 $ — With a related allowance for loan losses: Commercial: Commercial real estate $ 2.6 $ 2.3 $ 0.1 $ 23.8 $ 21.8 $ 1.6 Commercial and industrial 22.4 18.9 5.6 12.6 10.2 2.4 Equipment financing 14.6 14.3 1.6 16.2 12.8 2.7 Retail: Residential mortgage 11.5 11.5 1.5 8.8 8.8 1.7 Home equity 1.4 1.4 0.6 1.7 1.6 0.7 Other consumer — — — — — — Total $ 52.5 $ 48.4 $ 9.4 $ 63.1 $ 55.2 $ 9.1 Total impaired loans: Commercial: Commercial real estate $ 41.5 $ 38.0 $ 0.1 $ 54.8 $ 49.9 $ 1.6 Commercial and industrial 57.3 48.8 5.6 58.2 52.2 2.4 Equipment financing 35.8 33.5 1.6 36.4 30.8 2.7 Total 134.6 120.3 7.3 149.4 132.9 6.7 Retail: Residential mortgage 80.6 72.9 1.5 75.6 68.1 1.7 Home equity 27.9 24.6 0.6 25.5 21.9 0.7 Other consumer — — — — — — Total 108.5 97.5 2.1 101.1 90.0 2.4 Total $ 243.1 $ 217.8 $ 9.4 $ 250.5 $ 222.9 $ 9.1
Schedule of Impaired Financing Receivable	The following tables summarize, by class of loan, the average recorded investment and interest income recognized on impaired loans for the periods indicated. The average recorded investment amounts are based on month-end balances. Three Months Ended September 30, 2019 2018 (in millions) Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Commercial: Commercial real estate $ 28.8 $ 0.4 $ 36.2 $ 0.4 Commercial and industrial 47.6 0.3 52.4 0.2 Equipment financing 28.5 0.1 36.0 0.1 Total 104.9 0.8 124.6 0.7 Retail: Residential mortgage 70.5 0.6 68.6 0.4 Home equity 23.9 0.2 20.7 0.2 Other consumer — — — — Total 94.4 0.8 89.3 0.6 Total $ 199.3 $ 1.6 $ 213.9 $ 1.3 Nine Months Ended September 30, 2019 2018 (in millions) Average Interest Average Interest Commercial: Commercial real estate $ 39.9 $ 0.8 $ 40.7 $ 0.9 Commercial and industrial 44.3 1.4 50.6 1.3 Equipment financing 25.5 0.2 39.8 0.2 Total 109.7 2.4 131.1 2.4 Retail: Residential mortgage 67.2 1.6 69.5 1.3 Home equity 22.7 0.5 21.0 0.4 Other consumer — — — — Total 89.9 2.1 90.5 1.7 Total $ 199.6 $ 4.5 $ 221.6 $ 4.1
Summary of Aging Information by Class of Loan	The following tables summarize, by class of loan, aging information for originated loans: Past Due As of September 30, 2019 (in millions) Current 30-89 Days 90 Days or More Total Total Originated Commercial: Commercial real estate $ 9,695.6 $ 5.2 $ 20.6 $ 25.8 $ 9,721.4 Commercial and industrial 9,696.4 9.1 14.6 23.7 9,720.1 Equipment financing 4,389.0 84.2 11.3 95.5 4,484.5 Total 23,781.0 98.5 46.5 145.0 23,926.0 Retail: Residential mortgage 6,614.2 25.2 22.3 47.5 6,661.7 Home equity 1,673.2 6.3 6.2 12.5 1,685.7 Other consumer 39.0 0.2 0.1 0.3 39.3 Total 8,326.4 31.7 28.6 60.3 8,386.7 Total originated loans $ 32,107.4 $ 130.2 $ 75.1 $ 205.3 $ 32,312.7 Included in the “Current” and “30-89 Days” categories above are early non-performing commercial real estate loans, commercial and industrial loans, and equipment financing loans totaling $4.6 million, $24.4 million and $30.2 million, respectively, and $22.4 million of retail loans in the process of foreclosure or bankruptcy. These loans are less than 90 days past due but have been placed on non-accrual status as a result of having been identified as presenting uncertainty with respect to the collectability of interest and principal. Past Due As of December 31, 2018 (in millions) Current 30-89 Days 90 Days or More Total Total Originated Commercial: Commercial real estate $ 9,762.1 $ 23.0 $ 13.4 $ 36.4 $ 9,798.5 Commercial and industrial 8,261.5 6.9 23.9 30.8 8,292.3 Equipment financing 3,855.3 68.8 13.6 82.4 3,937.7 Total 21,878.9 98.7 50.9 149.6 22,028.5 Retail: Residential mortgage 6,723.2 38.6 27.4 66.0 6,789.2 Home equity 1,776.0 5.8 7.7 13.5 1,789.5 Other consumer 42.7 0.1 — 0.1 42.8 Total 8,541.9 44.5 35.1 79.6 8,621.5 Total originated loans $ 30,420.8 $ 143.2 $ 86.0 $ 229.2 $ 30,650.0
Summary of Credit Quality Indicators by Class of Loan	The following tables summarize, by class of loan, credit quality indicators: As of September 30, 2019 (in millions) Commercial Real Estate Commercial and Industrial Equipment Financing Total Commercial: Originated loans: Pass $ 9,448.6 $ 9,178.2 $ 4,056.4 $ 22,683.2 Special mention 194.3 270.4 82.5 547.2 Substandard 77.6 271.2 345.6 694.4 Doubtful 0.9 0.3 — 1.2 Total originated loans 9,721.4 9,720.1 4,484.5 23,926.0 Acquired loans: Pass 2,382.2 764.7 248.6 3,395.5 Special mention 38.1 17.7 — 55.8 Substandard 45.2 43.3 2.5 91.0 Doubtful — 0.1 — 0.1 Total acquired loans 2,465.5 825.8 251.1 3,542.4 Total $ 12,186.9 $ 10,545.9 $ 4,735.6 $ 27,468.4 As of September 30, 2019 (in millions) Residential Mortgage Home Equity Other Consumer Total Retail: Originated loans: Low risk $ 3,362.7 $ 785.9 $ 24.0 $ 4,172.6 Moderate risk 2,763.9 555.6 5.7 3,325.2 High risk 535.1 344.2 9.6 888.9 Total originated loans 6,661.7 1,685.7 39.3 8,386.7 Acquired loans: Low risk 1,228.9 — — 1,228.9 Moderate risk 1,166.7 — — 1,166.7 High risk 251.4 271.2 8.1 530.7 Total acquired loans 2,647.0 271.2 8.1 2,926.3 Total $ 9,308.7 $ 1,956.9 $ 47.4 $ 11,313.0 As of December 31, 2018 (in millions) Commercial Real Estate Commercial and Industrial Equipment Financing Total Commercial: Originated loans: Pass $ 9,607.0 $ 7,855.7 $ 3,549.3 $ 21,012.0 Special mention 105.5 196.9 92.1 394.5 Substandard 85.2 239.3 296.3 620.8 Doubtful 0.8 0.4 — 1.2 Total originated loans 9,798.5 8,292.3 3,937.7 22,028.5 Acquired loans: Pass 1,766.2 719.6 394.0 2,879.8 Special mention 27.3 14.6 4.7 46.6 Substandard 57.6 62.4 2.8 122.8 Doubtful — — — — Total acquired loans 1,851.1 796.6 401.5 3,049.2 Total $ 11,649.6 $ 9,088.9 $ 4,339.2 $ 25,077.7 As of December 31, 2018 (in millions) Residential Mortgage Home Equity Other Consumer Total Retail: Originated loans: Low risk $ 2,912.8 $ 834.5 $ 27.3 $ 3,774.6 Moderate risk 3,360.9 576.4 5.9 3,943.2 High risk 515.5 378.6 9.6 903.7 Total originated loans 6,789.2 1,789.5 42.8 8,621.5 Acquired loans: Low risk 506.1 — — 506.1 Moderate risk 639.6 — — 639.6 High risk 219.3 173.0 4.2 396.5 Total acquired loans 1,365.0 173.0 4.2 1,542.2 Total $ 8,154.2 $ 1,962.5 $ 47.0 $ 10,163.7
Summarized Activity in Accretable Yield for PCI Loan Portfolio	The following table summarizes activity in the accretable yield for the PCI loan portfolio: Three Months Ended Nine Months Ended (in millions) 2019 2018 2019 2018 Balance at beginning of period $ 154.3 $ 190.2 $ 189.7 $ 219.7 Accretion (4.5) (5.6) (15.5) (17.9) Reclassification from nonaccretable difference for loans with improved cash flows (1) — — — — Other changes in expected cash flows (2) (13.2) — (37.6) (17.2) Balance at end of period $ 136.6 $ 184.6 $ 136.6 $ 184.6 1. Results in increased interest accretion as a prospective yield adjustment over the remaining life of the corresponding pool of loans. 2. Represents changes in cash flows expected to be collected due to factors other than credit (e.g. changes in prepayment assumptions and/or changes in interest rates on variable rate loans), as well as loan sales, modifications and payoffs.

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
Stockholders' Equity (Tables)	Sep. 30, 2019
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Loss	The following is a summary of the changes in the components of AOCL, which are included in People’s United’s stockholders’ equity on an after-tax basis: (in millions) Pension and Other Postretirement Plans Net Unrealized Gains (Losses) on Debt Securities Available-for-Sale Net Unrealized Gains (Losses) on Debt Securities Transferred to Held-to-Maturity Net Unrealized Gains (Losses) on Derivatives Accounted for as Cash Flow Hedges Total AOCL Balance at December 31, 2018 $ (192.5) $ (47.0) $ (15.3) $ (2.0) $ (256.8) Other comprehensive income — 66.2 — 1.6 67.8 Amounts reclassified from AOCL (1) 3.9 — 2.0 0.8 6.7 Current period other comprehensive 3.9 66.2 2.0 2.4 74.5 Balance at September 30, 2019 $ (188.6) $ 19.2 $ (13.3) $ 0.4 $ (182.3) (in millions) Pension and Other Postretirement Plans Net Unrealized Gains (Losses) on Debt Securities Available-for-Sale Net Unrealized Gains (Losses) on Debt Securities Transferred to Held-to-Maturity Net Unrealized Gains (Losses) on Derivatives Accounted for as Cash Flow Hedges Total AOCL Balance at December 31, 2017 $ (144.1) $ (21.6) $ (15.1) $ (0.9) $ (181.7) Other comprehensive income — (56.2) — (2.4) (58.6) Amounts reclassified from AOCL (1) 4.5 (0.1) 2.3 0.1 6.8 Current period other comprehensive 4.5 (56.3) 2.3 (2.3) (51.8) Transition adjustments related to (30.0) (3.9) (3.2) (0.2) (37.3) Balance at September 30, 2018 $ (169.6) $ (81.8) $ (16.0) $ (3.4) $ (270.8) 1. See the following table for details about these reclassifications. 2. See Notes 3 and 15.
Summary of Amounts Reclassified from AOCL	The following is a summary of the amounts reclassified from AOCL: Amounts Reclassified from AOCL Affected Line Item in the Statement Where Net Income is Presented Three Months Ended Nine Months Ended (in millions) 2019 2018 2019 2018 Details about components of AOCL: Amortization of pension and other postretirement plans items: Net actuarial loss $ (1.4) $ (2.0) $ (4.1) $ (6.2) (1) Prior service credit — — — 0.2 (1) (1.4) (2.0) (4.1) (6.0) Income before income tax expense 0.4 0.5 0.2 1.5 Income tax expense (1.0) (1.5) (3.9) (4.5) Net income Reclassification adjustment for net realized gains (losses) on debt securities available-for-sale — — — 0.1 Income before income tax expense (2) — — — — Income tax expense — — — 0.1 Net income Amortization of unrealized losses on debt securities transferred to held-to-maturity (1.1) (0.9) (2.7) (3.0) Income before income tax expense (3) 0.3 0.2 0.7 0.7 Income tax expense (0.8) (0.7) (2.0) (2.3) Net income Amortization of unrealized gains and losses on cash flow hedges: Interest rate swaps (0.3) (0.3) (1.1) (0.3) (4) Interest rate locks 0.1 0.1 0.1 0.1 (4) (0.2) (0.2) (1.0) (0.2) Income before income tax expense — 0.1 0.2 0.1 Income tax expense (0.2) (0.1) (0.8) (0.1) Net income Total reclassifications for the period $ (2.0) $ (2.3) $ (6.7) $ (6.8) 1. Included in the computation of net periodic benefit income (expense) reflected in other non-interest expense (see Note 8 for additional details). 2. Included in other non-interest income. 3. Included in interest and dividend income - securities. 4. Included in interest expense - notes and debentures.

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	9 Months Ended
Earnings Per Common Share (Tables)	Sep. 30, 2019
Earnings Per Share [Abstract]
Basic and Diluted Earnings Per Common Share, Reflecting Application of Two-Class Method	The following is an analysis of People’s United’s basic and diluted earnings per common share (“EPS”), reflecting the application of the two-class method, as described below: Three Months Ended Nine Months Ended (in millions, except per common share data) 2019 2018 2019 2018 Net income available to common shareholders $ 131.6 $ 113.5 $ 372.5 $ 324.6 Dividends paid on and undistributed earnings allocated to (0.1) — (0.2) (0.2) Earnings attributable to common shareholders $ 131.5 $ 113.5 $ 372.3 $ 324.4 Weighted average common shares outstanding for basic EPS 391.7 341.4 384.6 340.6 Effect of dilutive equity-based awards 2.8 3.6 3.2 3.9 Weighted average common shares and common-equivalent 394.5 345.0 387.8 344.5 EPS: Basic $ 0.34 $ 0.33 $ 0.97 $ 0.95 Diluted 0.33 0.33 0.96 0.94

Goodwill and Other Acquisitio_2

Goodwill and Other Acquisition-Related Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Changes in Carrying Amount of Goodwill	Changes in the carrying amounts of People’s United’s goodwill are summarized as follows for the nine months ended September 30, 2019 and 2018, respectively. Operating Segment (in millions) Commercial Banking Retail Banking Wealth Management Total Balance at December 31, 2018 $ 1,759.4 $ 835.3 $ 91.0 $ 2,685.7 Acquisition of: VAR 37.5 — — 37.5 BSB Bancorp 49.3 95.6 — 144.9 Balance at September 30, 2019 $ 1,846.2 $ 930.9 $ 91.0 $ 2,868.1 Operating Segment (in millions) Commercial Banking Retail Banking Wealth Management Total Balance at December 31, 2017 $ 1,600.3 $ 720.1 $ 91.0 $ 2,411.4 Acquisition of Vend Lease Company 23.8 — — 23.8 Balance at September 30, 2018 $ 1,624.1 $ 720.1 $ 91.0 $ 2,435.2

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	9 Months Ended
Employee Benefit Plans (Tables)	Sep. 30, 2019
Retirement Benefits [Abstract]
Components of Net Periodic Benefit (Income) Expense and Other Amounts	Components of net periodic benefit (income) expense and other amounts recognized in other comprehensive income (loss) for (i) the People’s Qualified Plan, the First Connecticut Qualified Plan, the People's Supplemental Plans and the First Connecticut Supplemental Plan (together the “Pension Plans”) and (ii) the People's Postretirement Plan and the First Connecticut Postretirement Plans (together the "Other Postretirement Plans") are as follows: Pension Plans Other Three months ended September 30 (in millions) 2019 2018 2019 2018 Net periodic benefit (income) expense: Interest cost $ 5.7 $ 4.9 $ 0.2 $ 0.2 Expected return on plan assets (11.4) (10.9) — — Recognized net actuarial loss 1.3 2.0 0.1 — Recognized prior service credit — — — — Settlements 0.4 (0.5) — — Net periodic benefit (income) expense (1) $ (4.0) $ (4.5) $ 0.3 $ 0.2 Pension Plans Other Postretirement Plans Nine months ended September 30 (in millions) 2019 2018 2019 2018 Net periodic benefit (income) expense: Interest cost $ 17.1 $ 14.6 $ 0.7 $ 0.6 Expected return on plan assets (34.3) (32.7) — — Recognized net actuarial loss 4.0 6.0 0.1 0.2 Recognized prior service credit — (0.2) — — Settlements 1.3 0.4 — — Net periodic benefit (income) expense (11.9) (11.9) 0.8 0.8 Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss): Net actuarial loss (4.0) (6.0) (0.1) (0.2) Prior service credit — 0.2 — — Total pre-tax changes recognized in other comprehensive income (loss) (4.0) (5.8) (0.1) (0.2) Total recognized in net periodic benefit (income) expense and other comprehensive income (loss) $ (15.9) $ (17.7) $ 0.7 $ 0.6

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
Fair Value Measurements (Tables)	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on Recurring Basis	The following tables summarize People’s United’s financial instruments that are measured at fair value on a recurring basis: Fair Value Measurements Using As of September 30, 2019 (in millions) Level 1 Level 2 Level 3 Total Financial assets: Trading debt securities: U.S. Treasury $ 9.3 $ — $ — $ 9.3 Debt securities available-for-sale: U.S. Treasury and agency 688.1 — — 688.1 GSE mortgage-backed securities — 2,290.6 — 2,290.6 Equity securities 7.8 — — 7.8 Other assets: Exchange-traded funds 45.3 — — 45.3 Mutual funds 3.8 — — 3.8 Interest rate swaps — 421.1 — 421.1 Interest rate caps — 2.1 — 2.1 Foreign exchange contracts — 1.4 — 1.4 Forward commitments to sell residential — 0.4 — 0.4 Total $ 754.3 $ 2,715.6 $ — $ 3,469.9 Financial liabilities: Interest rate swaps $ — $ 74.3 $ — $ 74.3 Interest rate caps — 2.1 — 2.1 Risk participation agreements — 0.2 — 0.2 Foreign exchange contracts — 1.3 — 1.3 Interest rate-lock commitments on residential — 0.5 — 0.5 Total $ — $ 78.4 $ — $ 78.4 Fair Value Measurements Using As of December 31, 2018 (in millions) Level 1 Level 2 Level 3 Total Financial assets: Trading debt securities: U.S. Treasury $ 8.4 $ — $ — $ 8.4 Debt securities available-for-sale: U.S. Treasury and agency 678.0 — — 678.0 GSE mortgage-backed securities — 2,443.0 — 2,443.0 Equity securities 8.1 — — 8.1 Other assets: Exchange-traded funds 35.5 — — 35.5 Mutual funds 20.6 — — 20.6 Fixed income securities — 0.3 — 0.3 Interest rate swaps — 98.9 — 98.9 Interest rate caps — 3.1 — 3.1 Foreign exchange contracts — 0.9 — 0.9 Forward commitments to sell residential — 0.1 — 0.1 Total $ 750.6 $ 2,546.3 $ — $ 3,296.9 Financial liabilities: Interest rate swaps $ — $ 135.0 $ — $ 135.0 Interest rate caps — 3.1 — 3.1 Risk participation agreements (1) — — — — Foreign exchange contracts — 0.8 — 0.8 Interest rate-lock commitments on residential — 0.1 — 0.1 Total $ — $ 139.0 $ — $ 139.0 1. At December 31, 2018, the fair value of risk participation agreements totaled less than $0.1 million (see Note 12).
Assets Measured at Fair Value on Non-Recurring Basis	The following tables summarize People’s United’s assets that are measured at fair value on a non-recurring basis: Fair Value Measurements Using As of September 30, 2019 (in millions) Level 1 Level 2 Level 3 Total Loans held-for-sale (1) $ — $ 24.8 $ — $ 24.8 Impaired loans (2) — — 48.4 48.4 REO and repossessed assets (3) — — 26.3 26.3 Total $ — $ 24.8 $ 74.7 $ 99.5 Fair Value Measurements Using As of December 31, 2018 (in millions) Level 1 Level 2 Level 3 Total Loans held-for-sale (1) $ — $ 19.5 $ — $ 19.5 Impaired loans (2) — — 55.2 55.2 REO and repossessed assets (3) — — 18.1 18.1 Total $ — $ 19.5 $ 73.3 $ 92.8 1. Consists of residential mortgage loans; no fair value adjustments were recorded for the nine months ended September 30, 2019 and 2018. 2. Represents the recorded investment in originated impaired loans with a related allowance for loan losses measured in accordance with applicable accounting guidance. The total consists of $35.5 million of Commercial loans and $12.9 million of Retail loans at September 30, 2019. The provision for loan losses on impaired loans totaled $5.3 million and $7.7 million for the nine months ended September 30, 2019 and 2018, respectively. 3. Represents: (i) $12.3 million of residential REO; (ii) $7.7 million of commercial REO; and (iii) $6.3 million of repossessed assets at September 30, 2019. Charge-offs to the allowance for loan losses related to loans that were transferred to REO or repossessed assets totaled $2.1 million and $1.0 million for the nine months ended September 30, 2019 and 2018, respectively. Write downs and net (gains) loss on sale of foreclosed/repossessed assets charged to non-interest expense totaled $(0.3) million and $0.1 million for the same periods.
Carrying Amounts and Estimated Fair Values of Financial Instruments	The following tables summarize the carrying amounts, estimated fair values and placement in the fair value hierarchy of People’s United’s financial instruments that are not measured at fair value either on a recurring or non-recurring basis: Carrying Amount Estimated Fair Value Measurements Using As of September 30, 2019 (in millions) Level 1 Level 2 Level 3 Total Financial assets: Cash and due from banks $ 635.2 $ 635.2 $ — $ — $ 635.2 Short-term investments 157.8 — 157.8 — 157.8 Debt securities held-to-maturity 3,805.4 — 3,970.0 1.5 3,971.5 FHLB and FRB stock 334.0 — 334.0 — 334.0 Total loans, net (1) 38,487.0 — 9,064.9 29,474.3 38,539.2 Financial liabilities: Time deposits 8,100.4 — 8,120.9 — 8,120.9 Other deposits 30,473.1 — 30,473.1 — 30,473.1 FHLB advances 2,948.5 — 2,948.8 — 2,948.8 Federal funds purchased 1,365.0 — 1,365.0 — 1,365.0 Customer repurchase agreements 315.6 — 315.6 — 315.6 Notes and debentures 915.7 — 936.8 — 936.8 1. Excludes impaired loans totaling $48.4 million measured at fair value on a non-recurring basis. Carrying Amount Estimated Fair Value Measurements Using As of December 31, 2018 (in millions) Level 1 Level 2 Level 3 Total Financial assets: Cash and due from banks $ 665.7 $ 665.7 $ — $ — $ 665.7 Short-term investments 266.3 — 266.3 — 266.3 Debt securities held-to-maturity 3,792.3 — 3,774.4 1.5 3,775.9 FHLB and FRB stock 303.4 — 303.4 — 303.4 Total loans, net (1) 34,945.8 — 7,806.1 26,800.2 34,606.3 Financial liabilities: Time deposits 6,916.2 — 6,884.0 — 6,884.0 Other deposits 29,242.8 — 29,242.8 — 29,242.8 FHLB advances 2,404.5 — 2,404.5 — 2,404.5 Federal funds purchased 845.0 — 845.0 — 845.0 Customer repurchase agreements 332.9 — 332.9 — 332.9 Other borrowings 11.0 — 11.0 — 11.0 Notes and debentures 895.8 — 893.4 — 893.4 1. Excludes impaired loans totaling $55.2 million measured at fair value on a non-recurring basis.

Derivative Financial Instrume_2

Derivative Financial Instruments and Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Notional Amounts and Fair Values of Derivatives Outstanding	The table below provides a summary of the notional amounts and fair values (presented on a gross basis) of derivatives outstanding: Fair Values (1) Notional Amounts Assets Liabilities (in millions) Type of Hedge Sept. 30, Dec 31, Sept. 30, Dec 31, 2018 Sept. 30, Dec 31, 2018 Derivatives Not Designated as Hedging Interest rate swaps: Commercial customers N/A $ 7,592.8 $ 7,455.9 $ 416.2 $ 76.3 $ 0.7 $ 102.6 Institutional counterparties N/A 7,599.6 7,161.3 4.9 22.6 73.6 32.4 Interest rate caps: Commercial customers N/A 264.2 329.1 2.1 0.6 — 2.5 Institutional counterparties N/A 264.2 329.1 — 2.5 2.1 0.6 Risk participation agreements (2) N/A 786.6 576.5 — — 0.2 — Foreign exchange contracts N/A 74.8 145.2 1.4 0.9 1.3 0.8 Forward commitments to sell N/A 34.8 9.5 0.4 0.1 — — Interest rate-lock commitments on N/A 54.9 13.6 — — 0.5 0.1 Total 425.0 103.0 78.4 139.0 Derivatives Designated as Hedging Interest rate swaps: Subordinated notes Fair value 375.0 375.0 — — — — Loans Cash flow 210.0 210.0 — — — — Total — — — — Total fair value of derivatives $ 425.0 $ 103.0 $ 78.4 $ 139.0 1. Assets are recorded in other assets and liabilities are recorded in other liabilities. 2. Fair value totaled less than $0.1 million at December 31, 2018.
Impact of Derivatives on Pre-Tax Income and Accumulated Other Comprehensive Loss	The following table summarizes the impact of People’s United’s derivatives on pre-tax income and AOCL: Type of Hedge Amount of Pre-Tax Gain (Loss) Recognized in Earnings (1) Amount of Pre-Tax Gain (Loss) Recognized in AOCL Nine months ended September 30 (in millions) 2019 2018 2019 2018 Derivatives Not Designated as Hedging Interest rate swaps: Commercial customers N/A $ 466.8 $ (177.1) $ — $ — Institutional counterparties N/A (451.3) 184.5 — — Interest rate caps: Commercial customers N/A 2.0 (0.7) — — Institutional counterparties N/A (2.0) 0.8 — — Foreign exchange contracts N/A 0.5 0.6 — — Risk participation agreements N/A 0.1 0.2 — — Forward commitments to sell N/A 0.3 — — — Interest rate-lock commitments on N/A (0.3) — — — Total 16.1 8.3 — — Derivatives Designated as Hedging Interest rate swaps Fair value (0.2) (1.8) — — Interest rate swaps Cash flow (1.1) (0.3) 2.1 (3.1) Interest rate locks Cash flow 0.1 0.1 — — Total (1.2) (2.0) 2.1 (3.1) Total $ 14.9 $ 6.3 $ 2.1 $ (3.1) 1. Amounts recognized in earnings are recorded in interest income, interest expense or other non-interest income for derivatives designated as hedging instruments and in other non-interest income for derivatives not designated as hedging instruments.

Balance Sheet Offsetting (Table

Balance Sheet Offsetting (Tables)	9 Months Ended
Balance Sheet Offsetting (Tables)	Sep. 30, 2019
Offsetting [Abstract]
Summary of Gross Presentation, Financial Instruments that are Eligible for Offset Not Offset in Consolidated Statement of Condition	The following tables provide a gross presentation, the effects of offsetting, and a net presentation of the Company’s financial instruments that are eligible for offset in the Consolidated Statements of Condition. The collateral amounts in these tables are limited to the outstanding balances of the related asset or liability (after netting is applied) and, therefore, instances of overcollateralization are not presented. In the tables below, the Net Amount Presented of the derivative assets and liabilities can be reconciled to the fair value of the Company’s derivative financial instruments in Note 12. The Company’s derivative contracts with commercial customers and customer repurchase agreements are not subject to master netting arrangements and, therefore, have been excluded from the tables below. Gross Amount Recognized Gross Amount Offset Net Amount Presented Gross Amounts Not Offset Financial Instruments Net Amount As of September 30, 2019 (in millions) Collateral Financial assets: Interest rate swaps: Counterparty A $ — $ — $ — $ — $ — $ — Counterparty B 0.1 — 0.1 (0.1) — — Counterparty C 0.1 — 0.1 (0.1) — — Counterparty D — — — — — — Counterparty E 4.5 — 4.5 — — 4.5 Other counterparties 0.2 — 0.2 (0.2) — — Foreign exchange contracts 1.4 — 1.4 — — 1.4 Total $ 6.3 $ — $ 6.3 $ (0.4) $ — $ 5.9 Financial liabilities: Interest rate swaps: Counterparty A $ 3.2 $ — $ 3.2 $ — $ (3.2) $ — Counterparty B 7.1 — 7.1 (0.1) (7.0) — Counterparty C 23.8 — 23.8 (0.1) (23.7) — Counterparty D 7.6 — 7.6 — (7.6) — Counterparty E — — — — — — Other counterparties 34.0 — 34.0 (0.2) (33.2) 0.6 Foreign exchange contracts 1.3 — 1.3 — — 1.3 Total $ 77.0 $ — $ 77.0 $ (0.4) $ (74.7) $ 1.9 Gross Amount Recognized Gross Amount Offset Net Amount Presented Gross Amounts Not Offset Financial Instruments Net Amount As of December 31, 2018 (in millions) Collateral Financial assets: Interest rate swaps: Counterparty A $ 3.1 $ — $ 3.1 $ (1.4) $ (1.7) $ — Counterparty B 2.5 — 2.5 (2.5) — — Counterparty C 4.8 — 4.8 (3.7) (1.1) — Counterparty D 3.6 — 3.6 (2.7) (0.1) 0.8 Counterparty E — — — — — — Other counterparties 11.1 — 11.1 (5.4) (5.7) — Foreign exchange contracts 0.9 — 0.9 — — 0.9 Total $ 26.0 $ — $ 26.0 $ (15.7) $ (8.6) $ 1.7 Financial liabilities: Interest rate swaps: Counterparty A $ 1.4 $ — $ 1.4 $ (1.4) $ — $ — Counterparty B 3.8 — 3.8 (2.5) (1.2) 0.1 Counterparty C 3.7 — 3.7 (3.7) — — Counterparty D 2.7 — 2.7 (2.7) — — Counterparty E 16.0 — 16.0 — — 16.0 Other counterparties 5.4 — 5.4 (5.4) — — Foreign exchange contracts 0.8 — 0.8 — — 0.8 Total $ 33.8 $ — $ 33.8 $ (15.7) $ (1.2) $ 16.9
Summary of Collateral Swaps	The following tables show the extent to which assets and liabilities exchanged under resale and repurchase agreements have been offset in the Consolidated Statements of Condition. These agreements: (i) are entered into simultaneously with the same financial institution counterparty; (ii) have the same principal amounts and inception/maturity dates; and (iii) are subject to a master netting arrangement that contains a conditional right of offset upon default. At September 30, 2019 and December 31, 2018, the Company posted as collateral marketable securities with fair values of $462.6 million and $461.3 million, respectively, and, in turn, accepted as collateral marketable securities with fair values of $458.2 million and $457.2 million, respectively. As of September 30, 2019 (in millions) Gross Amount Recognized Gross Amount Offset Net Amount Presented Total resale agreements $ 450.0 $ (450.0) $ — Total repurchase agreements $ 450.0 $ (450.0) $ — As of December 31, 2018 (in millions) Gross Amount Recognized Gross Amount Offset Net Amount Presented Total resale agreements $ 450.0 $ (450.0) $ — Total repurchase agreements $ 450.0 $ (450.0) $ —

Leases (Tables)

Leases (Tables)	9 Months Ended
Leases (Tables)	Sep. 30, 2019
Leases [Abstract]
Composition of Total Net Investment in Lease Financing Receivables	The composition of the Company’s total net investment in lease financing receivables included within equipment financing loans in the Consolidated Statements of Condition was as follows: (in millions) September 30, 2019 Lease payments receivable $ 1,380.0 Estimated residual value of leased assets 128.4 Gross investment in lease financing receivables 1,508.4 Plus: Deferred origination costs 13.5 Less: Unearned income (154.4) Total net investment in lease financing receivables $ 1,367.5
Contractual Maturities of Lease Financing Receivables	The contractual maturities of the Company's lease financing receivables were as follows: (in millions) September 30, 2019 2019 (1) $ 229.7 2020 454.8 2021 357.7 2022 245.2 2023 137.0 Later years 84.0 Total $ 1,508.4 1. Contractual maturities for the three months remaining in 2019.
Lease Costs	The following tables provide the components of lease cost and supplemental information: Three Months Ended Nine Months Ended (in millions) September 30, 2019 September 30, 2019 Operating lease cost $ 15.0 $ 45.4 Variable lease cost 2.0 6.4 Sublease income (0.3) (1.0) Net lease cost $ 16.7 $ 50.8
Lease Costs	(dollars in millions) As of and for Nine Months Ended September 30, 2019 Lease ROU assets $ 235.6 Lease liabilities 260.5 Cash payments included in the measurement of lease liabilities reported in operating cash flows 45.8 ROU assets obtained in exchange for lessee operating lease liabilities (1) 30.3 Weighted average discount rate 3.28 % Weighted average remaining lease term (in years) 7.0 1. Amount excludes related transition adjustment (see Note 15).
Lease Right-of-use Assets and Liabilities	(dollars in millions) As of and for Nine Months Ended September 30, 2019 Lease ROU assets $ 235.6 Lease liabilities 260.5 Cash payments included in the measurement of lease liabilities reported in operating cash flows 45.8 ROU assets obtained in exchange for lessee operating lease liabilities (1) 30.3 Weighted average discount rate 3.28 % Weighted average remaining lease term (in years) 7.0 1. Amount excludes related transition adjustment (see Note 15).
Schedule of Contractual Maturities of Lease Liabilities	The contractual maturities of the Company's lease liabilities were as follows: (in millions) September 30, 2019 2019 (1) $ 15.1 2020 59.1 2021 56.7 2022 39.5 2023 28.3 Later years 102.8 Total lease payments 301.5 Less: Interest (41.0) Total lease liabilities $ 260.5 1. Contractual maturities for the three months remaining in 2019.

General (Detail)

General (Detail) - USD ($) $ in Millions	Jan. 02, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Description of Business and Summary of Significant Accounting Policies [Line Items]
Affordable housing investments		$ 368.7		$ 368.7		$ 304.1
Future contingent commitments		145.5		$ 145.5		$ 119.7
Amortization period				10 years
Income tax expense		$ 6.4	$ 4.8	$ 18.5	$ 14
Var Technology Finance
Description of Business and Summary of Significant Accounting Policies [Line Items]
Business acquisition, date of acquisition agreement	Jan. 2, 2019
Merger related expenses				$ 1.9

Acquisitions - Fair Value of As

Acquisitions - Fair Value of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions	Sep. 30, 2019	Apr. 01, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Assets:
Goodwill	$ 2,868.1		$ 2,685.7	$ 2,435.2	$ 2,411.4
BSB Bancorp
Assets:
Cash and cash equivalents		$ 108.7
Securities		175.8
Loans		2,642.9
Goodwill		144.9
Core deposit intangible		39.5
Premises and equipment		8.3
Bank-owned life insurance		36.8
Other assets		29.8
Total assets		3,186.7
Liabilities:
Deposits		2,118.7
Borrowings		696.6
Other liabilities		46.9
Total liabilities		2,862.2
Total purchase price		$ 324.5

Acquisitions - Additional Infor

Acquisitions - Additional Information (Details) shares in Millions, $ in Millions	Apr. 01, 2019USD ($)branchshares	Jan. 02, 2019USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Business Acquisition [Line Items]
Portfolio outstanding balance			$ 375.1		$ 375.1		$ 491.6
Interest income			$ 424.7	$ 342.1	1,241.2	$ 984.6
BSB Bancorp
Business Acquisition [Line Items]
Business acquisition, date of acquisition agreement	Apr. 1, 2019
Business acquisition common stock fair value	$ 324.5
Business acquisition common stock shares (in shares) \| shares	19.7
Number of branches to be acquired \| branch	6
Merger-related expenses					7.3
Net deferred tax liabilities	$ 3.8
Interest income					42.2
BSB Bancorp \| Core Deposit Intangibles
Business Acquisition [Line Items]
Useful life	10 years
BSB Bancorp \| Purchased performing
Business Acquisition [Line Items]
Payment to acquire lease and loan portfolio	$ 2,640
Portfolio outstanding balance	$ 2,690
Var Technology Finance
Business Acquisition [Line Items]
Business acquisition, date of acquisition agreement		Jan. 2, 2019
Payment to acquire lease and loan portfolio		$ 60
Merger related expenses					$ 1.9

Acquisitions - Pro Forma (Detai

Acquisitions - Pro Forma (Details) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Selected Financial Results:
Net interest income	$ 1,044.7	$ 949.1
Provision for loan losses	21	20.1
Non-interest income	308.2	281.3
Non-interest expense	837.5	756.7
Net income	395.5	355.6
Net income applicable to common shareholders	$ 385	$ 345.1
Basic (in dollars per share)	$ 0.98	$ 0.96
Diluted (in dollars per share)	$ 0.98	$ 0.95

Cash and Cash Equivalents and_3

Cash and Cash Equivalents and Securities - Additional Information (Detail)	Jan. 01, 2018USD ($)	Sep. 30, 2019USD ($)Security	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)Security	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Investment [Line Items]
Debt security available for sale with a fair value pledged with collateral for public deposits		$ 2,070,000,000		$ 2,070,000,000		$ 2,200,000,000
Debt security available for sale with a held-to-maturity pledged with collateral for public deposits		1,650,000,000		1,650,000,000		1,490,000,000
Debt securities with unrealized losses		$ 6,300,000		$ 6,300,000		69,300,000
Percentage of securities available for sale		6.00%		6.00%
Number of debt securities owned \| Security		2,165		2,165
Number of debt securities classified as available-for-sale \| Security		64		64
Number of debt securities classified as held-to-maturity \| Security		69		69
Available for sale securities unrealized losses		$ 6,300,000		$ 6,300,000		69,300,000
Held to maturity securities gross unrealized losses		600,000		600,000		52,300,000
Other-than-temporary impairment losses recognized in earnings		0	$ 0	0	$ 0
Unrealized (losses) gains due to change in fair value of equity securities		(500,000)	$ 200,000	400,000	$ 1,000,000
Impairment of investments				$ 0
Federal Reserve Bank stock percentage				6.00%
Federal Reserve Bank of New York
Investment [Line Items]
Interest-bearing deposits		$ 50,600,000		$ 50,600,000		$ 234,000,000
Investment interest rate		1.80%		1.80%		2.40%
Acquired shares of capital stock		$ 203,600,000		$ 203,600,000		$ 178,500,000
FHLB of New York
Investment [Line Items]
Acquired shares of capital stock						700,000
FHLB of Boston
Investment [Line Items]
Acquired shares of capital stock		129,700,000		129,700,000		124,200,000
Accounting Standards Update 2016-01
Investment [Line Items]
Equity securities with an amortized cost							$ 9,600,000
Equity securities, at fair value							$ 8,700,000
Cumulative effect transition adjustments	$ 600,000
GSE mortgage-backed securities
Investment [Line Items]
Debt securities with unrealized losses		3,500,000		3,500,000		48,200,000
Available for sale securities unrealized losses		3,400,000		3,400,000		48,200,000
Held to maturity securities gross unrealized losses		100,000		$ 100,000		33,200,000
Available for sale securities average maturity period				11 years
State and municipal
Investment [Line Items]
Held to maturity securities gross unrealized losses		300,000		$ 300,000		$ 18,400,000
Held to maturity securities average maturity period				7 years
Maximum
Investment [Line Items]
Debt securities with unrealized losses		$ 100,000		$ 100,000

Cash and Cash Equivalents and_4

Cash and Cash Equivalents and Securities - Available-for-Sale and Held-to-Maturity Debt Securities Gains (Losses) (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Debt securities available-for-sale:
Amortized Cost	$ 2,960.3	$ 3,185.6
Gross Unrealized Gains	24.7	4.7
Gross Unrealized Losses	(6.3)	(69.3)
Fair Value	2,978.7	3,121
Debt securities held-to-maturity:
Amortized Cost	3,805.4	3,792.3
Gross Unrealized Gains	166.7	35.9
Gross Unrealized Losses	(0.6)	(52.3)
Fair Value	3,971.5	3,775.9
U.S. Treasury and agency
Debt securities available-for-sale:
Amortized Cost	690.6	699
Gross Unrealized Gains	0.4	0.1
Gross Unrealized Losses	(2.9)	(21.1)
Fair Value	688.1	678
Debt securities held-to-maturity:
Amortized Cost	0
Fair Value	0
GSE mortgage-backed securities
Debt securities available-for-sale:
Amortized Cost	2,269.7	2,486.6
Gross Unrealized Gains	24.3	4.6
Gross Unrealized Losses	(3.4)	(48.2)
Fair Value	2,290.6	2,443
Debt securities held-to-maturity:
Amortized Cost	1,291.7	1,367.5
Gross Unrealized Gains	17	0
Gross Unrealized Losses	(0.1)	(33.2)
Fair Value	1,308.6	1,334.3
State and municipal
Debt securities available-for-sale:
Fair Value	0
Debt securities held-to-maturity:
Amortized Cost	2,432.3	2,352.4
Gross Unrealized Gains	148.3	35.4
Gross Unrealized Losses	(0.3)	(18.4)
Fair Value	2,580.3	2,369.4
Corporate
Debt securities available-for-sale:
Fair Value	0
Debt securities held-to-maturity:
Amortized Cost	79.9	70.9
Gross Unrealized Gains	1.4	0.5
Gross Unrealized Losses	(0.2)	(0.7)
Fair Value	81.1	70.7
Other
Debt securities available-for-sale:
Fair Value	0
Debt securities held-to-maturity:
Amortized Cost	1.5	1.5
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	$ 1.5	$ 1.5

Cash and Cash Equivalents and_5

Cash and Cash Equivalents and Securities - Summary of Amortized Cost and Fair Value to Contractual Maturity (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Investment [Line Items]
Available for Sale, Amortized Cost, Within 1 year	$ 158.9
Available for Sale, Amortized Cost, After 1 but within 5 years	627.1
Available for Sale, Amortized Cost, After 5 but within 10 years	714.9
Available for Sale, Amortized Cost, After 10 years	1,459.4
Amortized Cost	2,960.3	$ 3,185.6
Available for Sale, Fair Value, Within 1 year	158.9
Available for Sale, Fair Value, After 1 but within 5 years	626.9
Available for Sale, Fair Value, After 5 but within 10 years	730.6
Available for Sale, Fair Value, After 10 years	1,462.3
Available for Sale, Fair Value, Total	2,978.7	3,121
Held to Maturity, Amortized Cost, Within 1 year	21.3
Held to Maturity, Amortized Cost, After 1 but within 5 years	979.5
Held to Maturity, Amortized Cost, After 5 but within 10 years	697.9
Held to Maturity, Amortized Cost, After 10 years	2,106.7
Amortized Cost	3,805.4	3,792.3
Held to Maturity, Fair Value, Within 1 year	21.3
Held to Maturity, Fair Value, After 1 but within 5 years	1,000.4
Held to Maturity, Fair Value, After 5 but within 10 years	728.1
Held to Maturity, Fair Value, After 10 years	2,221.7
Held to Maturity, Fair Value, Total	3,971.5	3,775.9
U.S. Treasury and agency
Investment [Line Items]
Available for Sale, Amortized Cost, Within 1 year	158.9
Available for Sale, Amortized Cost, After 1 but within 5 years	531.7
Amortized Cost	690.6	699
Available for Sale, Fair Value, Within 1 year	158.9
Available for Sale, Fair Value, After 1 but within 5 years	529.2
Available for Sale, Fair Value, Total	688.1	678
Held to Maturity, Amortized Cost, Within 1 year	0
Held to Maturity, Amortized Cost, After 1 but within 5 years	0
Amortized Cost	0
Held to Maturity, Fair Value, Within 1 year	0
Held to Maturity, Fair Value, After 1 but within 5 years	0
Held to Maturity, Fair Value, Total	0
GSE mortgage-backed securities
Investment [Line Items]
Available for Sale, Amortized Cost, Within 1 year	0
Available for Sale, Amortized Cost, After 1 but within 5 years	95.4
Available for Sale, Amortized Cost, After 5 but within 10 years	714.9
Available for Sale, Amortized Cost, After 10 years	1,459.4
Amortized Cost	2,269.7	2,486.6
Available for Sale, Fair Value, Within 1 year	0
Available for Sale, Fair Value, After 1 but within 5 years	97.7
Available for Sale, Fair Value, After 5 but within 10 years	730.6
Available for Sale, Fair Value, After 10 years	1,462.3
Available for Sale, Fair Value, Total	2,290.6	2,443
Held to Maturity, Amortized Cost, Within 1 year	2.8
Held to Maturity, Amortized Cost, After 1 but within 5 years	766.4
Held to Maturity, Amortized Cost, After 5 but within 10 years	217
Held to Maturity, Amortized Cost, After 10 years	305.5
Amortized Cost	1,291.7	1,367.5
Held to Maturity, Fair Value, Within 1 year	2.8
Held to Maturity, Fair Value, After 1 but within 5 years	778.9
Held to Maturity, Fair Value, After 5 but within 10 years	221.3
Held to Maturity, Fair Value, After 10 years	305.6
Held to Maturity, Fair Value, Total	1,308.6	1,334.3
State and municipal
Investment [Line Items]
Available for Sale, Amortized Cost, Within 1 year	0
Available for Sale, Amortized Cost, After 1 but within 5 years	0
Available for Sale, Amortized Cost, After 5 but within 10 years	0
Available for Sale, Amortized Cost, After 10 years	0
Available for Sale, Fair Value, Within 1 year	0
Available for Sale, Fair Value, After 1 but within 5 years	0
Available for Sale, Fair Value, After 5 but within 10 years	0
Available for Sale, Fair Value, After 10 years	0
Available for Sale, Fair Value, Total	0
Held to Maturity, Amortized Cost, Within 1 year	12
Held to Maturity, Amortized Cost, After 1 but within 5 years	213.1
Held to Maturity, Amortized Cost, After 5 but within 10 years	406
Held to Maturity, Amortized Cost, After 10 years	1,801.2
Amortized Cost	2,432.3	2,352.4
Held to Maturity, Fair Value, Within 1 year	12
Held to Maturity, Fair Value, After 1 but within 5 years	221.5
Held to Maturity, Fair Value, After 5 but within 10 years	430.7
Held to Maturity, Fair Value, After 10 years	1,916.1
Held to Maturity, Fair Value, Total	2,580.3	2,369.4
Corporate
Investment [Line Items]
Available for Sale, Amortized Cost, Within 1 year	0
Available for Sale, Amortized Cost, After 5 but within 10 years	0
Available for Sale, Amortized Cost, After 10 years	0
Available for Sale, Fair Value, Within 1 year	0
Available for Sale, Fair Value, After 5 but within 10 years	0
Available for Sale, Fair Value, Total	0
Held to Maturity, Amortized Cost, Within 1 year	5
Held to Maturity, Amortized Cost, After 5 but within 10 years	74.9
Amortized Cost	79.9	70.9
Held to Maturity, Fair Value, Within 1 year	5
Held to Maturity, Fair Value, After 5 but within 10 years	76.1
Held to Maturity, Fair Value, Total	81.1	70.7
Other
Investment [Line Items]
Available for Sale, Amortized Cost, Within 1 year	0
Available for Sale, Amortized Cost, After 10 years	0
Available for Sale, Fair Value, Within 1 year	0
Available for Sale, Fair Value, Total	0
Held to Maturity, Amortized Cost, Within 1 year	1.5
Amortized Cost	1.5	1.5
Held to Maturity, Fair Value, Within 1 year	1.5
Held to Maturity, Fair Value, Total	$ 1.5	$ 1.5

Cash and Cash Equivalents and_6

Cash and Cash Equivalents and Securities - Continuous Unrealized Loss Positions (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 306.5	$ 132.4
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(0.6)	(0.5)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	1,163.1	2,312.5
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(5.7)	(68.8)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,469.6	2,444.9
Available-for-sale Securities, Unrealized Loss Position, Accumulated Loss	(6.3)	(69.3)
Continuous Unrealized Loss Position, Less Than 12 Months, Fair Value	126	144.6
Continuous Unrealized Loss Position, Less Than 12 Months, Unrealized Losses	(0.2)	(1.3)
Continuous Unrealized Loss Position, 12 Months Or Longer, Fair Value	29.9	2,034.6
Continuous Unrealized Loss Position, 12 Months Or Longer, Unrealized Losses	(0.4)	(51)
Continuous Unrealized Loss Position, Total, Fair Value	155.9	2,179.2
Continuous Unrealized Loss Position, Total, Unrealized Losses	(0.6)	(52.3)
GSE mortgage-backed securities
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	201.2	132.4
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(0.4)	(0.5)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	700	1,656.3
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(3.1)	(47.7)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	901.2	1,788.7
Available-for-sale Securities, Unrealized Loss Position, Accumulated Loss	(3.5)	(48.2)
Held To Maturity Securities, Continuous Unrealized Loss Position, Less Than 12 Months, Fair Value	110.4	0
Held To Maturity Securities, Continuous Unrealized Loss Position, Less Than 12 Months, Unrealized Losses	(0.1)	0
Held To Maturity Securities, Continuous Unrealized Loss Position, 12 Months Or Longer, Fair Value	9.5	1,334.3
Held To Maturity Securities, Continuous Unrealized Loss Position, 12 Months Or Longer, Unrealized Losses	0	(33.2)
Held To Maturity Securities, Continuous Unrealized Loss Position, Total, Fair Value	119.9	1,334.3
Held To Maturity Securities, Continuous Unrealized Loss Position, Total, Unrealized Losses	(0.1)	(33.2)
U.S. Treasury and agency
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	105.3	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(0.2)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	463.1	656.2
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(2.6)	(21.1)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	568.4	656.2
Available-for-sale Securities, Unrealized Loss Position, Accumulated Loss	(2.8)	(21.1)
State and municipal
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Held To Maturity Securities, Continuous Unrealized Loss Position, Less Than 12 Months, Fair Value	15.6	113.4
Held To Maturity Securities, Continuous Unrealized Loss Position, Less Than 12 Months, Unrealized Losses	(0.1)	(0.7)
Held To Maturity Securities, Continuous Unrealized Loss Position, 12 Months Or Longer, Fair Value	12	697.6
Held To Maturity Securities, Continuous Unrealized Loss Position, 12 Months Or Longer, Unrealized Losses	(0.2)	(17.7)
Held To Maturity Securities, Continuous Unrealized Loss Position, Total, Fair Value	27.6	811
Held To Maturity Securities, Continuous Unrealized Loss Position, Total, Unrealized Losses	(0.3)	(18.4)
Corporate
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Held To Maturity Securities, Continuous Unrealized Loss Position, Less Than 12 Months, Fair Value	0	31.2
Held To Maturity Securities, Continuous Unrealized Loss Position, Less Than 12 Months, Unrealized Losses	0	(0.6)
Held To Maturity Securities, Continuous Unrealized Loss Position, 12 Months Or Longer, Fair Value	8.4	2.7
Held To Maturity Securities, Continuous Unrealized Loss Position, 12 Months Or Longer, Unrealized Losses	(0.2)	(0.1)
Held To Maturity Securities, Continuous Unrealized Loss Position, Total, Fair Value	8.4	33.9
Held To Maturity Securities, Continuous Unrealized Loss Position, Total, Unrealized Losses	$ (0.2)	$ (0.7)

Loans - Additional Information

Loans - Additional Information (Detail)	3 Months Ended		9 Months Ended
Loans - Additional Information (Detail)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)RatingSegment	Sep. 30, 2018USD ($)	Jun. 30, 2019USD ($)	Dec. 31, 2018USD ($)	Jun. 30, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2011USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of segments \| Segment			2
Net deferred loan costs	$ 88,200,000		$ 88,200,000			$ 94,600,000
Recorded investments, non-performing loans	155,300,000		155,300,000			167,700,000
Loans past due and accruing	0		0			0
Allowance for loan losses	246,000,000	$ 238,000,000	246,000,000	$ 238,000,000	$ 244,000,000	240,400,000	$ 236,800,000	$ 234,400,000
Interest income recognized	1,600,000	1,300,000	$ 4,500,000	4,100,000
Temporary reduction of interest rate for TDRs, basis points			2.00%
Collateral values/LTV ratios, minimum			70.00%
Borrower credit scores, minimum \| Rating			680
Principal and interest payments receivable									$ 7,760,000,000
Expected cash flows									7,190,000,000
Loan portfolio fair value									5,490,000,000
Aggregate loan nonaccretable difference									572,000,000
Portfolio accretable yield	136,600,000	184,600,000	$ 136,600,000	184,600,000	154,300,000	189,700,000	190,200,000	219,700,000
Portfolio outstanding balance	375,100,000		375,100,000			491,600,000
Portfolio carrying value	291,300,000		291,300,000			399,900,000
Repossessed assets	6,300,000		$ 6,300,000			3,900,000
Temporary reduction of interest rate for TDRs, basis points			2.00%
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Early non-performing loans	4,600,000		$ 4,600,000			20,300,000
Real estate owned	7,700,000		7,700,000			8,700,000
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Early non-performing loans	24,400,000		24,400,000			15,800,000
Equipment financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Early non-performing loans	30,200,000		30,200,000			28,400,000
Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Real estate owned	12,300,000		12,300,000			5,500,000
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investments, non-performing loans	104,300,000		104,300,000			113,500,000
Allowance for loan losses	216,800,000	207,100,000	216,800,000	207,100,000	214,600,000	209,500,000	205,800,000	204,500,000
Interest income recognized	800,000	700,000	2,400,000	2,400,000
Commercial \| Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investments, non-performing loans	25,100,000		25,100,000			33,500,000
Interest income recognized	400,000	400,000	800,000	900,000
Commercial \| Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investments, non-performing loans	37,700,000		37,700,000			38,000,000
Interest income recognized	300,000	200,000	1,400,000	1,300,000
Commercial \| Equipment financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investments, non-performing loans	41,500,000		41,500,000			42,000,000
Interest income recognized	100,000	100,000	200,000	200,000
Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investments, non-performing loans	51,000,000		51,000,000			54,200,000
Allowance for loan losses	29,200,000	30,900,000	29,200,000	30,900,000	$ 29,400,000	30,900,000	$ 31,000,000	$ 29,900,000
Interest income recognized	800,000	600,000	2,100,000	1,700,000
Retail \| Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investments, non-performing loans	36,600,000		36,600,000			38,900,000
Interest income recognized	600,000	400,000	$ 1,600,000	1,300,000
Maximum \| Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Duration of extension for payment deferral on TDRs, years			2 years
Maximum \| Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Duration of extension for payment deferral on TDRs, years			5 years
Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan agreement			6 months
At Acquisition
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio accretable yield									$ 1,700,000,000
Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investments, non-performing loans	10,100,000		$ 10,100,000			44,100,000
Acquired \| Purchased performing \| Subsequent to Acquisition
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investments, non-performing loans	11,000,000		11,000,000			6,000,000
Troubled Debt Restructurings
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in originated loans classified as TDRs	180,600,000		180,600,000			179,400,000
Allowance for loan losses	3,600,000		3,600,000			4,500,000
Interest income recognized	1,500,000	$ 1,200,000	4,300,000	$ 4,000,000
Foreclosure or Bankruptcy
Accounts, Notes, Loans and Financing Receivable [Line Items]
Early non-performing loans	$ 22,400,000		$ 22,400,000			$ 19,100,000

Loans - Summary of Loans by Loa

Loans - Summary of Loans by Loan Portfolio Segment and Class (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 38,781.4	$ 35,241.4
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	27,468.4	25,077.7
Commercial \| Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	12,186.9	11,649.6
Commercial \| Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	10,545.9	9,088.9
Commercial \| Equipment financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	4,735.6	4,339.2
Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	11,313	10,163.7
Retail \| Adjustable-rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	6,916.4	6,662
Retail \| Fixed-rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,392.3	1,492.2
Retail \| Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	9,308.7	8,154.2
Retail \| Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,956.9	1,962.5
Retail \| Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	47.4	47
Retail \| Home equity and other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,004.3	2,009.5
Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	32,312.7	30,650
Originated \| Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	23,926	22,028.5
Originated \| Commercial \| Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	9,721.4	9,798.5
Originated \| Commercial \| Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	9,720.1	8,292.3
Originated \| Commercial \| Equipment financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	4,484.5	3,937.7
Originated \| Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	8,386.7	8,621.5
Originated \| Retail \| Adjustable-rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	5,547.9	5,854.1
Originated \| Retail \| Fixed-rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,113.8	935.1
Originated \| Retail \| Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	6,661.7	6,789.2
Originated \| Retail \| Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,685.7	1,789.5
Originated \| Retail \| Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	39.3	42.8
Originated \| Retail \| Home equity and other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,725	1,832.3
Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	6,468.7	4,591.4
Acquired \| Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	3,542.4	3,049.2
Acquired \| Commercial \| Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,465.5	1,851.1
Acquired \| Commercial \| Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	825.8	796.6
Acquired \| Commercial \| Equipment financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	251.1	401.5
Acquired \| Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,926.3	1,542.2
Acquired \| Retail \| Adjustable-rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,368.5	807.9
Acquired \| Retail \| Fixed-rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,278.5	557.1
Acquired \| Retail \| Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,647	1,365
Acquired \| Retail \| Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	271.2	173
Acquired \| Retail \| Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	8.1	4.2
Acquired \| Retail \| Home equity and other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 279.3	$ 177.2

Loans - Summary, by Loan Portfo

Loans - Summary, by Loan Portfolio Segment, of Activity in Allowance for Loan Losses (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	$ 244	$ 236.8	$ 240.4	$ 234.4
Charge-offs	(8.2)	(8.4)	(23)	(21.8)
Recoveries	2.4	1.4	7.6	5.3
Net loan charge-offs	(5.8)	(7)	(15.4)	(16.5)
Provision for loan losses	7.8	8.2	21	20.1
Balance at end of period	246	238	246	238
Commercial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	214.6	205.8	209.5	204.5
Charge-offs	(7.5)	(7.7)	(20.1)	(19.2)
Recoveries	1.9	1	5.3	3.6
Net loan charge-offs	(5.6)	(6.7)	(14.8)	(15.6)
Provision for loan losses	7.8	8	22.1	18.2
Balance at end of period	216.8	207.1	216.8	207.1
Commercial \| Originated
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	210.9	202	205.6	201.1
Charge-offs	(6.1)	(5.7)	(13.9)	(12.9)
Recoveries	1.6	0.6	4.2	2.6
Net loan charge-offs	(4.5)	(5.1)	(9.7)	(10.3)
Provision for loan losses	6.9	6.3	17.4	12.4
Balance at end of period	213.3	203.2	213.3	203.2
Commercial \| Acquired
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	3.7	3.8	3.9	3.4
Charge-offs	(1.4)	(2)	(6.2)	(6.3)
Recoveries	0.3	0.4	1.1	1
Net loan charge-offs	(1.1)	(1.6)	(5.1)	(5.3)
Provision for loan losses	0.9	1.7	4.7	5.8
Balance at end of period	3.5	3.9	3.5	3.9
Retail
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	29.4	31	30.9	29.9
Charge-offs	(0.7)	(0.7)	(2.9)	(2.6)
Recoveries	0.5	0.4	2.3	1.7
Net loan charge-offs	(0.2)	(0.3)	(0.6)	(0.9)
Provision for loan losses	0	0.2	(1.1)	1.9
Balance at end of period	29.2	30.9	29.2	30.9
Retail \| Originated
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	29.2	30.8	30.7	29.7
Charge-offs	(0.7)	(0.7)	(2.9)	(2.6)
Recoveries	0.5	0.4	2.3	1.7
Net loan charge-offs	(0.2)	(0.3)	(0.6)	(0.9)
Provision for loan losses	0	0.2	(1.1)	1.9
Balance at end of period	29	30.7	29	30.7
Retail \| Acquired
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	0.2	0.2	0.2	0.2
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Net loan charge-offs	0	0	0	0
Provision for loan losses	0	0	0	0
Balance at end of period	$ 0.2	$ 0.2	$ 0.2	$ 0.2

Loans - Summary of Allowance fo

Loans - Summary of Allowance for Loan Losses by Loan Portfolio Segment and Impairment Methodology (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	$ 38,781.4		$ 35,241.4
Total Allowance	246	$ 244	240.4	$ 238	$ 236.8	$ 234.4
Originated
Financing Receivable, Allowance for Credit Losses [Line Items]
Collectively evaluated for impairment	32,109.5		30,435.1
Individually evaluated for impairment	203.3		214.9
Total loans	32,312.7		30,650
Originated Loans Collectively Evaluated for Impairment, Allowance	232.9		227.3
Originated Loans Individually Evaluated for Impairment, Allowance	9.4		9
PCI
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	291.2		399.9
Total Allowance	2.4		2.3
No credit deterioration \| Purchased performing
Financing Receivable, Allowance for Credit Losses [Line Items]
Collectively evaluated for impairment	6,162.9		4,183.5
Individually evaluated for impairment	14.5		8
Originated Loans Collectively Evaluated for Impairment, Allowance	1.3		1.7
Originated Loans Individually Evaluated for Impairment, Allowance	0		0.1
Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	27,468.4		25,077.7
Total Allowance	216.8	214.6	209.5	207.1	205.8	204.5
Commercial \| Originated
Financing Receivable, Allowance for Credit Losses [Line Items]
Collectively evaluated for impairment	22,258.6		21,900.1
Individually evaluated for impairment	112.7		128.4
Total loans	23,926		22,028.5
Originated Loans Collectively Evaluated for Impairment, Allowance	206		198.9
Originated Loans Individually Evaluated for Impairment, Allowance	7.3		6.7
Total Allowance	213.3	210.9	205.6	203.2	202	201.1
Commercial \| PCI
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	219		300.3
Total Allowance	2.2		2.2
Commercial \| No credit deterioration \| Purchased performing
Financing Receivable, Allowance for Credit Losses [Line Items]
Collectively evaluated for impairment	4,870.5		2,744.4
Individually evaluated for impairment	7.6		4.5
Originated Loans Collectively Evaluated for Impairment, Allowance	1.3		1.7
Originated Loans Individually Evaluated for Impairment, Allowance	0		0
Retail
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	11,313		10,163.7
Total Allowance	29.2	29.4	30.9	30.9	31	29.9
Retail \| Originated
Financing Receivable, Allowance for Credit Losses [Line Items]
Collectively evaluated for impairment	9,850.9		8,535
Individually evaluated for impairment	90.6		86.5
Total loans	8,386.7		8,621.5
Originated Loans Collectively Evaluated for Impairment, Allowance	26.9		28.4
Originated Loans Individually Evaluated for Impairment, Allowance	2.1		2.3
Total Allowance	29	$ 29.2	30.7	$ 30.7	$ 30.8	$ 29.7
Retail \| PCI
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	72.2		99.6
Total Allowance	0.2		0.1
Retail \| No credit deterioration \| Purchased performing
Financing Receivable, Allowance for Credit Losses [Line Items]
Collectively evaluated for impairment	1,292.4		1,439.1
Individually evaluated for impairment	6.9		3.5
Originated Loans Collectively Evaluated for Impairment, Allowance	0		0
Originated Loans Individually Evaluated for Impairment, Allowance	$ 0		$ 0.1

Loans - Summarized Recorded Inv

Loans - Summarized Recorded Investments, by Class of Loan, in Originated Non-Performing Loans (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investments, non-performing loans	$ 155.3	$ 167.7
Government guarantees	1.4	1.9
Foreclosure
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investments, non-performing loans	22.1	24.8
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investments, non-performing loans	104.3	113.5
Retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investments, non-performing loans	$ 51	54.2
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Guarantee rate	5.00%
Commercial real estate \| Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investments, non-performing loans	$ 25.1	33.5
Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Guarantee rate	95.00%
Commercial and industrial \| Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investments, non-performing loans	$ 37.7	38
Equipment financing \| Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investments, non-performing loans	41.5	42
Residential mortgage \| Retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investments, non-performing loans	36.6	38.9
Home equity \| Retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investments, non-performing loans	14.3	15.3
Other consumer \| Retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investments, non-performing loans	$ 0.1	$ 0

Loans - Summary of Recorded Inv

Loans - Summary of Recorded Investments in TDRs by Class of Loan (Detail) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)contract	Sep. 30, 2018USD ($)contract	Sep. 30, 2019USD ($)contract	Sep. 30, 2018USD ($)contract
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	55	42	224	131
Pre-Modification Outstanding Recorded Investment	$ 34.5	$ 44.9	$ 93.3	$ 109.7
Post-Modification Outstanding Recorded Investment	$ 34.5	$ 44.9	$ 93.3	$ 109.7
Commercial
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	25	19	68	59
Pre-Modification Outstanding Recorded Investment	$ 26.7	$ 41.3	$ 64.1	$ 99.9
Post-Modification Outstanding Recorded Investment	$ 26.7	$ 41.3	$ 64.1	$ 99.9
Retail
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	30	23	156	72
Pre-Modification Outstanding Recorded Investment	$ 7.8	$ 3.6	$ 29.2	$ 9.8
Post-Modification Outstanding Recorded Investment	$ 7.8	$ 3.6	$ 29.2	$ 9.8
Commercial real estate \| Commercial
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	7	4	8	9
Pre-Modification Outstanding Recorded Investment	$ 13.1	$ 20.7	$ 13.7	$ 24.3
Post-Modification Outstanding Recorded Investment	$ 13.1	$ 20.7	$ 13.7	$ 24.3
Commercial real estate \| Commercial \| Extended Maturity
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	5	3	5	8
Post-Modification Outstanding Recorded Investment	$ 1.7	$ 20.2	$ 1.7	$ 23.8
Commercial real estate \| Commercial \| Payment Deferral
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract		1	1	1
Post-Modification Outstanding Recorded Investment		$ 0.5	$ 0.6	$ 0.5
Commercial real estate \| Commercial \| Combination of Concessions
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	2		2
Post-Modification Outstanding Recorded Investment	$ 11.4		$ 11.4
Commercial and industrial \| Commercial
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	8	10	27	34
Pre-Modification Outstanding Recorded Investment	$ 4.1	$ 10.3	$ 27.5	$ 55.2
Post-Modification Outstanding Recorded Investment	$ 4.1	$ 10.3	$ 27.5	$ 55.2
Commercial and industrial \| Commercial \| Extended Maturity
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	5	6	22	21
Post-Modification Outstanding Recorded Investment	$ 1.9	$ 3.6	$ 24.3	$ 30.7
Commercial and industrial \| Commercial \| Payment Deferral
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	2	2	2	10
Post-Modification Outstanding Recorded Investment	$ 0.3	$ 6.4	$ 0.3	$ 23.8
Commercial and industrial \| Commercial \| Combination of Concessions
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	1	2	3	3
Post-Modification Outstanding Recorded Investment	$ 1.9	$ 0.3	$ 2.9	$ 0.7
Equipment financing \| Commercial
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	10	5	33	16
Pre-Modification Outstanding Recorded Investment	$ 9.5	$ 10.3	$ 22.9	$ 20.4
Post-Modification Outstanding Recorded Investment	$ 9.5	$ 10.3	$ 22.9	$ 20.4
Equipment financing \| Commercial \| Extended Maturity
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	1	2	5	2
Post-Modification Outstanding Recorded Investment	$ 0.4	$ 3.3	$ 1.6	$ 3.3
Equipment financing \| Commercial \| Payment Deferral
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	5	2	22	8
Post-Modification Outstanding Recorded Investment	$ 5.1	$ 5.9	$ 16.9	$ 12.9
Equipment financing \| Commercial \| Combination of Concessions
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	4	1	6	6
Post-Modification Outstanding Recorded Investment	$ 4	$ 1.1	$ 4.4	$ 4.2
Residential mortgage \| Retail
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	15	4	73	16
Pre-Modification Outstanding Recorded Investment	$ 6.5	$ 1.4	$ 22.2	$ 4.9
Post-Modification Outstanding Recorded Investment	$ 6.5	$ 1.4	$ 22.2	$ 4.9
Residential mortgage \| Retail \| Payment Deferral
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	9	1	21	6
Post-Modification Outstanding Recorded Investment	$ 3.7	$ 0.7	$ 8.4	$ 2.4
Residential mortgage \| Retail \| Combination of Concessions
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	2	1	13	5
Post-Modification Outstanding Recorded Investment	$ 1.2	$ 0.1	$ 5.6	$ 1.6
Residential mortgage \| Retail \| Bankruptcy
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	4	2	39	5
Post-Modification Outstanding Recorded Investment	$ 1.6	$ 0.6	$ 8.2	$ 0.9
Home equity \| Retail
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	15	19	83	56
Pre-Modification Outstanding Recorded Investment	$ 1.3	$ 2.2	$ 7	$ 4.9
Post-Modification Outstanding Recorded Investment	$ 1.3	$ 2.2	$ 7	$ 4.9
Home equity \| Retail \| Payment Deferral
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	5	6	16	10
Post-Modification Outstanding Recorded Investment	$ 0.6	$ 1	$ 2.8	$ 1.3
Home equity \| Retail \| Combination of Concessions
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	4	2	19	9
Post-Modification Outstanding Recorded Investment	$ 0.3	$ 0.1	$ 1.6	$ 0.8
Home equity \| Retail \| Bankruptcy
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	6	11	48	37
Post-Modification Outstanding Recorded Investment	$ 0.4	$ 1.1	$ 2.6	$ 2.8
Other consumer \| Retail
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	0	0	0	0
Pre-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 0	$ 0
Post-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 0	$ 0

Loans - Summary of Recorded I_2

Loans - Summary of Recorded Investments in TDRs by Class of Loan, Subsequently Defaulted (Detail) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)contract	Sep. 30, 2018USD ($)contract	Sep. 30, 2019USD ($)contract	Sep. 30, 2018USD ($)contract
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	7	18	24	38
Recorded Investment as of Period End \| $	$ 1.2	$ 6.7	$ 11.4	$ 18
Commercial
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	2	5	9	22
Recorded Investment as of Period End \| $	$ 0.5	$ 5.2	$ 8.4	$ 16.1
Commercial \| Commercial real estate
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	1	0	1	2
Recorded Investment as of Period End \| $	$ 0.2	$ 0	$ 0.2	$ 0.8
Commercial \| Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	0	4	0	13
Recorded Investment as of Period End \| $	$ 0	$ 5	$ 0	$ 8.5
Commercial \| Equipment financing
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	1	1	8	7
Recorded Investment as of Period End \| $	$ 0.3	$ 0.2	$ 8.2	$ 6.8
Retail
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	5	13	15	16
Recorded Investment as of Period End \| $	$ 0.7	$ 1.5	$ 3	$ 1.9
Retail \| Residential mortgage
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	2	5	6	7
Recorded Investment as of Period End \| $	$ 0.6	$ 0.9	$ 2.4	$ 1.3
Retail \| Home equity
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	3	8	9	9
Recorded Investment as of Period End \| $	$ 0.1	$ 0.6	$ 0.6	$ 0.6
Retail \| Other consumer
Financing Receivable, Modifications [Line Items]
Number of Contracts \| contract	0	0	0	0
Recorded Investment as of Period End \| $	$ 0	$ 0	$ 0	$ 0

Loans - Summary of Individually

Loans - Summary of Individually-Evaluated Impaired Loans by Class of Loan (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
With no related allowance for loan losses, Unpaid Principal Balance	$ 190.6	$ 187.4
With no related allowance for loan losses, Recorded Investment	169.4	167.7
With a related allowance for loan losses, Unpaid Principal Balance	52.5	63.1
With a related allowance for loan losses, Recorded Investment	48.4	55.2
Unpaid Principal Balance	243.1	250.5
Recorded Investment	217.8	222.9
Related Allowance for Loan Losses	9.4	9.1
Commercial
Financing Receivable, Impaired [Line Items]
With a related allowance for loan losses, Recorded Investment	35.5
Unpaid Principal Balance	134.6	149.4
Recorded Investment	120.3	132.9
Related Allowance for Loan Losses	7.3	6.7
Commercial \| Commercial real estate
Financing Receivable, Impaired [Line Items]
With no related allowance for loan losses, Unpaid Principal Balance	38.9	31
With no related allowance for loan losses, Recorded Investment	35.7	28.1
With a related allowance for loan losses, Unpaid Principal Balance	2.6	23.8
With a related allowance for loan losses, Recorded Investment	2.3	21.8
Unpaid Principal Balance	41.5	54.8
Recorded Investment	38	49.9
Related Allowance for Loan Losses	0.1	1.6
Commercial \| Commercial and industrial
Financing Receivable, Impaired [Line Items]
With no related allowance for loan losses, Unpaid Principal Balance	34.9	45.6
With no related allowance for loan losses, Recorded Investment	29.9	42
With a related allowance for loan losses, Unpaid Principal Balance	22.4	12.6
With a related allowance for loan losses, Recorded Investment	18.9	10.2
Unpaid Principal Balance	57.3	58.2
Recorded Investment	48.8	52.2
Related Allowance for Loan Losses	5.6	2.4
Commercial \| Equipment financing
Financing Receivable, Impaired [Line Items]
With no related allowance for loan losses, Unpaid Principal Balance	21.2	20.2
With no related allowance for loan losses, Recorded Investment	19.2	18
With a related allowance for loan losses, Unpaid Principal Balance	14.6	16.2
With a related allowance for loan losses, Recorded Investment	14.3	12.8
Unpaid Principal Balance	35.8	36.4
Recorded Investment	33.5	30.8
Related Allowance for Loan Losses	1.6	2.7
Retail
Financing Receivable, Impaired [Line Items]
With a related allowance for loan losses, Recorded Investment	12.9
Unpaid Principal Balance	108.5	101.1
Recorded Investment	97.5	90
Related Allowance for Loan Losses	2.1	2.4
Retail \| Residential mortgage
Financing Receivable, Impaired [Line Items]
With no related allowance for loan losses, Unpaid Principal Balance	69.1	66.8
With no related allowance for loan losses, Recorded Investment	61.4	59.3
With a related allowance for loan losses, Unpaid Principal Balance	11.5	8.8
With a related allowance for loan losses, Recorded Investment	11.5	8.8
Unpaid Principal Balance	80.6	75.6
Recorded Investment	72.9	68.1
Related Allowance for Loan Losses	1.5	1.7
Retail \| Home equity
Financing Receivable, Impaired [Line Items]
With no related allowance for loan losses, Unpaid Principal Balance	26.5	23.8
With no related allowance for loan losses, Recorded Investment	23.2	20.3
With a related allowance for loan losses, Unpaid Principal Balance	1.4	1.7
With a related allowance for loan losses, Recorded Investment	1.4	1.6
Unpaid Principal Balance	27.9	25.5
Recorded Investment	24.6	21.9
Related Allowance for Loan Losses	0.6	0.7
Retail \| Other consumer
Financing Receivable, Impaired [Line Items]
With no related allowance for loan losses, Unpaid Principal Balance	0	0
With no related allowance for loan losses, Recorded Investment	0	0
With a related allowance for loan losses, Unpaid Principal Balance	0	0
With a related allowance for loan losses, Recorded Investment	0	0
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Related Allowance for Loan Losses	$ 0	$ 0

Loans - Schedule of Impaired Fi

Loans - Schedule of Impaired Financing Receivable (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	$ 199.3	$ 213.9	$ 199.6	$ 221.6
Interest Income Recognized	1.6	1.3	4.5	4.1
Commercial
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	104.9	124.6	109.7	131.1
Interest Income Recognized	0.8	0.7	2.4	2.4
Commercial \| Commercial real estate
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	28.8	36.2	39.9	40.7
Interest Income Recognized	0.4	0.4	0.8	0.9
Commercial \| Commercial and industrial
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	47.6	52.4	44.3	50.6
Interest Income Recognized	0.3	0.2	1.4	1.3
Commercial \| Equipment financing
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	28.5	36	25.5	39.8
Interest Income Recognized	0.1	0.1	0.2	0.2
Retail
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	94.4	89.3	89.9	90.5
Interest Income Recognized	0.8	0.6	2.1	1.7
Retail \| Residential mortgage
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	70.5	68.6	67.2	69.5
Interest Income Recognized	0.6	0.4	1.6	1.3
Retail \| Home equity
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	23.9	20.7	22.7	21
Interest Income Recognized	0.2	0.2	0.5	0.4
Retail \| Other consumer
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	0	0	0	0
Interest Income Recognized	$ 0	$ 0	$ 0	$ 0

Loans - Summary of Aging Inform

Loans - Summary of Aging Information by Class of Loan (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	$ 38,781.4	$ 35,241.4
Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	32,107.4	30,420.8
Total Past Due	205.3	229.2
Total loans	32,312.7	30,650
Originated \| 30-89 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	130.2	143.2
Originated \| 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	75.1	86
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	27,468.4	25,077.7
Commercial \| Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	12,186.9	11,649.6
Commercial \| Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	10,545.9	9,088.9
Commercial \| Equipment financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	4,735.6	4,339.2
Commercial \| Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	23,781	21,878.9
Total Past Due	145	149.6
Total loans	23,926	22,028.5
Commercial \| Originated \| Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	9,695.6	9,762.1
Total Past Due	25.8	36.4
Total loans	9,721.4	9,798.5
Commercial \| Originated \| Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	9,696.4	8,261.5
Total Past Due	23.7	30.8
Total loans	9,720.1	8,292.3
Commercial \| Originated \| Equipment financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	4,389	3,855.3
Total Past Due	95.5	82.4
Total loans	4,484.5	3,937.7
Commercial \| Originated \| 30-89 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	98.5	98.7
Commercial \| Originated \| 30-89 Days \| Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5.2	23
Commercial \| Originated \| 30-89 Days \| Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	9.1	6.9
Commercial \| Originated \| 30-89 Days \| Equipment financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	84.2	68.8
Commercial \| Originated \| 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	46.5	50.9
Commercial \| Originated \| 90 Days or More \| Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	20.6	13.4
Commercial \| Originated \| 90 Days or More \| Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	14.6	23.9
Commercial \| Originated \| 90 Days or More \| Equipment financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	11.3	13.6
Retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	11,313	10,163.7
Retail \| Residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	9,308.7	8,154.2
Retail \| Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	1,956.9	1,962.5
Retail \| Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	47.4	47
Retail \| Originated
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	8,326.4	8,541.9
Total Past Due	60.3	79.6
Total loans	8,386.7	8,621.5
Retail \| Originated \| Residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	6,614.2	6,723.2
Total Past Due	47.5	66
Total loans	6,661.7	6,789.2
Retail \| Originated \| Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,673.2	1,776
Total Past Due	12.5	13.5
Total loans	1,685.7	1,789.5
Retail \| Originated \| Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	39	42.7
Total Past Due	0.3	0.1
Total loans	39.3	42.8
Retail \| Originated \| 30-89 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	31.7	44.5
Retail \| Originated \| 30-89 Days \| Residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	25.2	38.6
Retail \| Originated \| 30-89 Days \| Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6.3	5.8
Retail \| Originated \| 30-89 Days \| Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0.2	0.1
Retail \| Originated \| 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	28.6	35.1
Retail \| Originated \| 90 Days or More \| Residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	22.3	27.4
Retail \| Originated \| 90 Days or More \| Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6.2	7.7
Retail \| Originated \| 90 Days or More \| Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 0.1	$ 0

Loans - Summary of Credit Quali

Loans - Summary of Credit Quality Indicators by Class of Loan (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 38,781.4	$ 35,241.4
Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	27,468.4	25,077.7
Retail
Financing Receivable, Recorded Investment [Line Items]
Loans	11,313	10,163.7
Originated \| Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	23,926	22,028.5
Originated \| Commercial \| Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	22,683.2	21,012
Originated \| Commercial \| Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	547.2	394.5
Originated \| Commercial \| Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	694.4	620.8
Originated \| Commercial \| Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	1.2	1.2
Originated \| Retail
Financing Receivable, Recorded Investment [Line Items]
Loans	8,386.7	8,621.5
Originated \| Retail \| Low risk
Financing Receivable, Recorded Investment [Line Items]
Loans	4,172.6	3,774.6
Originated \| Retail \| Moderate risk
Financing Receivable, Recorded Investment [Line Items]
Loans	3,325.2	3,943.2
Originated \| Retail \| High risk
Financing Receivable, Recorded Investment [Line Items]
Loans	888.9	903.7
Acquired \| Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	3,542.4	3,049.2
Acquired \| Commercial \| Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	3,395.5	2,879.8
Acquired \| Commercial \| Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	55.8	46.6
Acquired \| Commercial \| Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	91	122.8
Acquired \| Commercial \| Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0.1	0
Acquired \| Retail
Financing Receivable, Recorded Investment [Line Items]
Loans	2,926.3	1,542.2
Acquired \| Retail \| Low risk
Financing Receivable, Recorded Investment [Line Items]
Loans	1,228.9	506.1
Acquired \| Retail \| Moderate risk
Financing Receivable, Recorded Investment [Line Items]
Loans	1,166.7	639.6
Acquired \| Retail \| High risk
Financing Receivable, Recorded Investment [Line Items]
Loans	530.7	396.5
Commercial real estate \| Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	12,186.9	11,649.6
Commercial real estate \| Originated \| Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	9,721.4	9,798.5
Commercial real estate \| Originated \| Commercial \| Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	9,448.6	9,607
Commercial real estate \| Originated \| Commercial \| Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	194.3	105.5
Commercial real estate \| Originated \| Commercial \| Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	77.6	85.2
Commercial real estate \| Originated \| Commercial \| Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0.9	0.8
Commercial real estate \| Acquired \| Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	2,465.5	1,851.1
Commercial real estate \| Acquired \| Commercial \| Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	2,382.2	1,766.2
Commercial real estate \| Acquired \| Commercial \| Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	38.1	27.3
Commercial real estate \| Acquired \| Commercial \| Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	45.2	57.6
Commercial real estate \| Acquired \| Commercial \| Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial and industrial \| Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	10,545.9	9,088.9
Commercial and industrial \| Originated \| Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	9,720.1	8,292.3
Commercial and industrial \| Originated \| Commercial \| Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	9,178.2	7,855.7
Commercial and industrial \| Originated \| Commercial \| Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	270.4	196.9
Commercial and industrial \| Originated \| Commercial \| Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	271.2	239.3
Commercial and industrial \| Originated \| Commercial \| Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0.3	0.4
Commercial and industrial \| Acquired \| Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	825.8	796.6
Commercial and industrial \| Acquired \| Commercial \| Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	764.7	719.6
Commercial and industrial \| Acquired \| Commercial \| Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	17.7	14.6
Commercial and industrial \| Acquired \| Commercial \| Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	43.3	62.4
Commercial and industrial \| Acquired \| Commercial \| Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0.1	0
Equipment financing \| Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	4,735.6	4,339.2
Equipment financing \| Originated \| Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	4,484.5	3,937.7
Equipment financing \| Originated \| Commercial \| Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	4,056.4	3,549.3
Equipment financing \| Originated \| Commercial \| Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	82.5	92.1
Equipment financing \| Originated \| Commercial \| Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	345.6	296.3
Equipment financing \| Originated \| Commercial \| Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Equipment financing \| Acquired \| Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans	251.1	401.5
Equipment financing \| Acquired \| Commercial \| Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	248.6	394
Equipment financing \| Acquired \| Commercial \| Special mention
Financing Receivable, Recorded Investment [Line Items]
Loans	0	4.7
Equipment financing \| Acquired \| Commercial \| Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	2.5	2.8
Equipment financing \| Acquired \| Commercial \| Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Residential mortgage \| Retail
Financing Receivable, Recorded Investment [Line Items]
Loans	9,308.7	8,154.2
Residential mortgage \| Originated \| Retail
Financing Receivable, Recorded Investment [Line Items]
Loans	6,661.7	6,789.2
Residential mortgage \| Originated \| Retail \| Low risk
Financing Receivable, Recorded Investment [Line Items]
Loans	3,362.7	2,912.8
Residential mortgage \| Originated \| Retail \| Moderate risk
Financing Receivable, Recorded Investment [Line Items]
Loans	2,763.9	3,360.9
Residential mortgage \| Originated \| Retail \| High risk
Financing Receivable, Recorded Investment [Line Items]
Loans	535.1	515.5
Residential mortgage \| Acquired \| Retail
Financing Receivable, Recorded Investment [Line Items]
Loans	2,647	1,365
Residential mortgage \| Acquired \| Retail \| Low risk
Financing Receivable, Recorded Investment [Line Items]
Loans	1,228.9	506.1
Residential mortgage \| Acquired \| Retail \| Moderate risk
Financing Receivable, Recorded Investment [Line Items]
Loans	1,166.7	639.6
Residential mortgage \| Acquired \| Retail \| High risk
Financing Receivable, Recorded Investment [Line Items]
Loans	251.4	219.3
Home equity \| Retail
Financing Receivable, Recorded Investment [Line Items]
Loans	1,956.9	1,962.5
Home equity \| Originated \| Retail
Financing Receivable, Recorded Investment [Line Items]
Loans	1,685.7	1,789.5
Home equity \| Originated \| Retail \| Low risk
Financing Receivable, Recorded Investment [Line Items]
Loans	785.9	834.5
Home equity \| Originated \| Retail \| Moderate risk
Financing Receivable, Recorded Investment [Line Items]
Loans	555.6	576.4
Home equity \| Originated \| Retail \| High risk
Financing Receivable, Recorded Investment [Line Items]
Loans	344.2	378.6
Home equity \| Acquired \| Retail
Financing Receivable, Recorded Investment [Line Items]
Loans	271.2	173
Home equity \| Acquired \| Retail \| Low risk
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Home equity \| Acquired \| Retail \| Moderate risk
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Home equity \| Acquired \| Retail \| High risk
Financing Receivable, Recorded Investment [Line Items]
Loans	271.2	173
Other consumer \| Retail
Financing Receivable, Recorded Investment [Line Items]
Loans	47.4	47
Other consumer \| Originated \| Retail
Financing Receivable, Recorded Investment [Line Items]
Loans	39.3	42.8
Other consumer \| Originated \| Retail \| Low risk
Financing Receivable, Recorded Investment [Line Items]
Loans	24	27.3
Other consumer \| Originated \| Retail \| Moderate risk
Financing Receivable, Recorded Investment [Line Items]
Loans	5.7	5.9
Other consumer \| Originated \| Retail \| High risk
Financing Receivable, Recorded Investment [Line Items]
Loans	9.6	9.6
Other consumer \| Acquired \| Retail
Financing Receivable, Recorded Investment [Line Items]
Loans	8.1	4.2
Other consumer \| Acquired \| Retail \| Low risk
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Other consumer \| Acquired \| Retail \| Moderate risk
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Other consumer \| Acquired \| Retail \| High risk
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 8.1	$ 4.2

Loans - Summarized Activity in

Loans - Summarized Activity in Accretable Yield for PCI Loan Portfolio (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance at beginning of period	$ 154.3	$ 190.2	$ 189.7	$ 219.7
Accretion	(4.5)	(5.6)	(15.5)	(17.9)
Reclassification from nonaccretable difference for loans with improved cash flows	0	0	0	0
Other changes in expected cash flows	(13.2)	0	(37.6)	(17.2)
Balance at end of period	$ 136.6	$ 184.6	$ 136.6	$ 184.6

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - $ / shares	4 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Schedule Of Stockholders Equity [Line Items]
Preferred stock, shares authorized (in shares)	50,000,000		50,000,000
Preferred stock par value, per share (USD per share)	$ 0.01		$ 0.01
Preferred stock, shares outstanding (in shares)	10,000,000		10,000,000
Common stock, shares authorized (in shares)	1,950,000,000		1,950,000,000
Common stock, par value (USD per share)	$ 0.01		$ 0.01
Common stock, shares issued (in shares)	487,600,000		466,300,000
Common stock purchased (in shares)	89,000,000		89,000,000
Number of shares authorized for repurchase (in shares)		20,000,000
Number of shares repurchased (in shares)	0
People's United Financial, Inc.
Schedule Of Stockholders Equity [Line Items]
Preferred stock, shares authorized (in shares)	50,000,000		50,000,000
Preferred stock par value, per share (USD per share)	$ 0.01		$ 0.01
Preferred stock, shares outstanding (in shares)	10,000,000		10,000,000
Common stock, shares authorized (in shares)	1,950,000,000		1,950,000,000
Common stock, par value (USD per share)	$ 0.01		$ 0.01
Common stock, shares issued (in shares)	487,600,000		466,300,000
Repurchases Authorized by Board of Directors
Schedule Of Stockholders Equity [Line Items]
Common stock purchased (in shares)	86,400,000		86,400,000
2007 Recognition and Retention Plan
Schedule Of Stockholders Equity [Line Items]
Common stock purchased (in shares)	2,600,000		2,600,000
2014 Long-Term Incentive Plan \| 2007 Recognition and Retention Plan
Schedule Of Stockholders Equity [Line Items]
Additional awards under RRP (in shares)	0

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 01, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 7,046.2	$ 5,900.2	$ 6,533.9	$ 5,819.9
Other comprehensive income (loss) before reclassifications			67.8	(58.6)
Amounts reclassified from AOCL			6.7	6.8
Total other comprehensive income (loss), net of tax (note 5)	10.7	(10.1)	74.5	(51.8)
Transition adjustments related to adoption of new accounting standards		0.6		0.6
Ending Balance	7,130.7	5,958.9	7,130.7	5,958.9
Pension and Other Postretirement Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			(192.5)	(144.1)
Other comprehensive income (loss) before reclassifications			0	0
Amounts reclassified from AOCL			3.9	4.5
Total other comprehensive income (loss), net of tax (note 5)			3.9	4.5
Transition adjustments related to adoption of new accounting standards					$ (30)
Ending Balance	(188.6)	(169.6)	(188.6)	(169.6)
Net Unrealized Gains (Losses) on Debt Securities Available-for-Sale
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			(47)	(21.6)
Other comprehensive income (loss) before reclassifications			66.2	(56.2)
Amounts reclassified from AOCL			0	(0.1)
Total other comprehensive income (loss), net of tax (note 5)			66.2	(56.3)
Transition adjustments related to adoption of new accounting standards					(3.9)
Ending Balance	19.2	(81.8)	19.2	(81.8)
Net Unrealized Gains (Losses) on Debt Securities Transferred to Held-to-Maturity
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			(15.3)	(15.1)
Other comprehensive income (loss) before reclassifications			0	0
Amounts reclassified from AOCL			2	2.3
Total other comprehensive income (loss), net of tax (note 5)			2	2.3
Transition adjustments related to adoption of new accounting standards					(3.2)
Ending Balance	(13.3)	(16)	(13.3)	(16)
Net Unrealized Gains (Losses) on Derivatives Accounted for as Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			(2)	(0.9)
Other comprehensive income (loss) before reclassifications			1.6	(2.4)
Amounts reclassified from AOCL			0.8	0.1
Total other comprehensive income (loss), net of tax (note 5)			2.4	(2.3)
Transition adjustments related to adoption of new accounting standards					(0.2)
Ending Balance	0.4	(3.4)	0.4	(3.4)
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(193)	(260.7)	(256.8)	(181.7)
Total other comprehensive income (loss), net of tax (note 5)	10.7	(10.1)	74.5	(51.8)
Transition adjustments related to adoption of new accounting standards		(37.3)		(37.3)	$ (37.3)
Ending Balance	$ (182.3)	$ (270.8)	$ (182.3)	$ (270.8)

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Amounts Reclassified from AOCL (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other non-interest expense	$ 31.4	$ 23.2	$ 89.2	$ 70.2
Interest expense - notes and debentures (interest rate locks are less than $0.1 million)	8.5	8.5	26.1	24.7
Income before income tax expense	(165.5)	(149.2)	(478.5)	(427.5)
Income tax expense	30.4	32.2	95.5	92.4
Net Income (Loss) Attributable to Parent	(135.1)	(117)	(383)	(335.1)
Reclassification out of AOCL
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net Income (Loss) Attributable to Parent	(2)	(2.3)	(6.7)	(6.8)
Reclassification out of AOCL \| Net Actuarial Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other non-interest expense	(1.4)	(2)	(4.1)	(6.2)
Reclassification out of AOCL \| Prior Service Credit
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other non-interest expense	0	0	0	0.2
Reclassification out of AOCL \| Pension and Other Postretirement Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income before income tax expense	(1.4)	(2)	(4.1)	(6)
Income tax expense	0.4	0.5	0.2	1.5
Net Income (Loss) Attributable to Parent	(1)	(1.5)	(3.9)	(4.5)
Reclassification out of AOCL \| Net Unrealized Gains (Losses) on Debt Securities Available-for-Sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income before income tax expense	0	0	0	0.1
Income tax expense	0	0	0	0
Net Income (Loss) Attributable to Parent	0	0	0	0.1
Reclassification out of AOCL \| Net Unrealized Gains (Losses) on Debt Securities Transferred to Held-to-Maturity
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income before income tax expense	(1.1)	(0.9)	(2.7)	(3)
Income tax expense	0.3	0.2	0.7	0.7
Net Income (Loss) Attributable to Parent	(0.8)	(0.7)	(2)	(2.3)
Reclassification out of AOCL \| Net Unrealized Gains (Losses) on Derivatives Accounted for as Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income before income tax expense	(0.2)	(0.2)	(1)	(0.2)
Income tax expense	0	0.1	0.2	0.1
Net Income (Loss) Attributable to Parent	(0.2)	(0.1)	(0.8)	(0.1)
Reclassification out of AOCL \| Net Unrealized Gains (Losses) on Derivatives Accounted for as Cash Flow Hedges \| Interest rate swaps
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest expense - notes and debentures (interest rate locks are less than $0.1 million)	(0.3)	(0.3)	(1.1)	(0.3)
Reclassification out of AOCL \| Net Unrealized Gains (Losses) on Derivatives Accounted for as Cash Flow Hedges \| Interest rate locks
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest expense - notes and debentures (interest rate locks are less than $0.1 million)	$ 0.1	$ 0.1	$ 0.1	$ 0.1

Earnings Per Common Share (Deta

Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Net income available to common shareholders	$ 131.6	$ 113.5	$ 372.5	$ 324.6
Dividends paid on and undistributed earnings allocated to participating securities	(0.1)	0	(0.2)	(0.2)
Earnings attributable to common shareholders	$ 131.5	$ 113.5	$ 372.3	$ 324.4
Weighted average common shares outstanding for basic EPS (in shares)	391.7	341.4	384.6	340.6
Effect of dilutive equity-based awards (in shares)	2.8	3.6	3.2	3.9
Weighted average common shares and common-equivalent shares for diluted EPS (in shares)	394.5	345	387.8	344.5
EPS:
Basic (USD per share)	$ 0.34	$ 0.33	$ 0.97	$ 0.95
Diluted (USD per share)	$ 0.33	$ 0.33	$ 0.96	$ 0.94
Anti-dilutive equity-based awards excluded from calculation of diluted EPS (in shares)	7.2	6.8	7.1	6.8

Goodwill and Other Acquisitio_3

Goodwill and Other Acquisition-Related Intangible Assets - Schedule of Changes in Goodwill (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Goodwill [Roll Forward]
Beginning balance	$ 2,685.7	$ 2,411.4
Ending balance	2,868.1	2,435.2
Var
Goodwill [Roll Forward]
Acquisition	37.5
BSB Bancorp
Goodwill [Roll Forward]
Acquisition	144.9
Vend Lease
Goodwill [Roll Forward]
Acquisition		23.8
Commercial Banking
Goodwill [Roll Forward]
Beginning balance	1,759.4	1,600.3
Ending balance	1,846.2	1,624.1
Commercial Banking \| Var
Goodwill [Roll Forward]
Acquisition	37.5
Commercial Banking \| BSB Bancorp
Goodwill [Roll Forward]
Acquisition	49.3
Commercial Banking \| Vend Lease
Goodwill [Roll Forward]
Acquisition		23.8
Retail Banking
Goodwill [Roll Forward]
Beginning balance	835.3	720.1
Ending balance	930.9	720.1
Retail Banking \| Var
Goodwill [Roll Forward]
Acquisition	0
Retail Banking \| BSB Bancorp
Goodwill [Roll Forward]
Acquisition	95.6
Retail Banking \| Vend Lease
Goodwill [Roll Forward]
Acquisition		0
Wealth Management
Goodwill [Roll Forward]
Beginning balance	91	91
Ending balance	91	91
Wealth Management \| Var
Goodwill [Roll Forward]
Acquisition	0
Wealth Management \| BSB Bancorp
Goodwill [Roll Forward]
Acquisition	$ 0
Wealth Management \| Vend Lease
Goodwill [Roll Forward]
Acquisition		$ 0

Goodwill and Other Acquisitio_4

Goodwill and Other Acquisition-Related Intangible Assets - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Goodwill And Other Intangible Assets [Line Items]
Tax deductible goodwill amount	$ 137,200,000		$ 137,200,000		$ 71,000,000
Other acquisition-related intangible assets	196,800,000		196,800,000		$ 180,000,000
Amortization of other acquisition-related intangible assets	8,000,000	$ 4,900,000	22,700,000	$ 14,900,000
Amortization expense attributable to other acquisition-related intangible assets, 2019	30,600,000		30,600,000
Amortization expense attributable to other acquisition-related intangible assets, 2020	29,700,000		29,700,000
Amortization expense attributable to other acquisition-related intangible assets, 2021	27,000,000		27,000,000
Amortization expense attributable to other acquisition-related intangible assets, 2022	24,600,000		24,600,000
Amortization expense attributable to other acquisition-related intangible assets, 2023	18,700,000		18,700,000
Amortization expense attributable to other acquisition-related intangible assets, 2024	17,000,000		17,000,000
Impairment losses relating to goodwill or other acquisition-related intangible assets			0	$ 0
Core Deposit Intangibles
Goodwill And Other Intangible Assets [Line Items]
Other acquisition-related intangible assets	91,800,000		91,800,000
Trade Name
Goodwill And Other Intangible Assets [Line Items]
Other acquisition-related intangible assets	54,100,000		54,100,000
Client Relationship
Goodwill And Other Intangible Assets [Line Items]
Other acquisition-related intangible assets	18,400,000		18,400,000
Trust relationships
Goodwill And Other Intangible Assets [Line Items]
Other acquisition-related intangible assets	9,300,000		9,300,000
Insurance Relationships
Goodwill And Other Intangible Assets [Line Items]
Other acquisition-related intangible assets	4,000,000		4,000,000
Favorable Lease Agreement
Goodwill And Other Intangible Assets [Line Items]
Other acquisition-related intangible assets	2,400,000		2,400,000
Noncompete Agreements
Goodwill And Other Intangible Assets [Line Items]
Other acquisition-related intangible assets	300,000		300,000
Mutual Fund Management Contracts
Goodwill And Other Intangible Assets [Line Items]
Mutual fund management contracts (not amortized)	$ 16,500,000		$ 16,500,000

Employee Benefit Plans - Employ

Employee Benefit Plans - Employee Pension and Other Postretirement Plans (Detail)	9 Months Ended
	Sep. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Average compensation term on which pension plan benefits are based, in years	5 years
Average compensation term within last ten years on which pension plan benefits are based, in years	5 years
Term considered when determining employee pension benefits, in years	10 years
Minimum age requirement to participate in pension plan, years	18 years
Minimum service hours per year requirement to participate in pension plan	1000 hours
People's Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Percentage of covered employee's eligible compensation	3.00%

Employee Benefit Plans - Compon

Employee Benefit Plans - Components of Net Periodic Benefit (Income) Expense and Other Amounts (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 5.7	$ 4.9	$ 17.1	$ 14.6
Expected return on plan assets	(11.4)	(10.9)	(34.3)	(32.7)
Recognized net actuarial loss	1.3	2	4	6
Recognized prior service credit	0	0	0	(0.2)
Settlements	0.4	(0.5)	1.3	0.4
Net periodic benefit (income) expense	(4)	(4.5)	(11.9)	(11.9)
Net actuarial loss			(4)	(6)
Prior service credit			0	0.2
Total pre-tax changes recognized in other comprehensive income (loss)			(4)	(5.8)
Total recognized in net periodic benefit (income) expense and other comprehensive income (loss)			(15.9)	(17.7)
Other Postretirement Plan
Defined Benefit Plan Disclosure [Line Items]
Interest cost	0.2	0.2	0.7	0.6
Expected return on plan assets	0	0	0	0
Recognized net actuarial loss	0.1	0	0.1	0.2
Recognized prior service credit	0	0	0	0
Settlements	0	0	0	0
Net periodic benefit (income) expense	$ 0.3	$ 0.2	0.8	0.8
Net actuarial loss			(0.1)	(0.2)
Prior service credit			0	0
Total pre-tax changes recognized in other comprehensive income (loss)			(0.1)	(0.2)
Total recognized in net periodic benefit (income) expense and other comprehensive income (loss)			$ 0.7	$ 0.6

Employee Benefit Plans - Empl_2

Employee Benefit Plans - Employee Stock Ownership Plan (Detail) - USD ($) $ in Millions	1 Months Ended	9 Months Ended
	Apr. 30, 2007	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Retirement Benefits [Abstract]
ESOP loan	$ 216.8	$ 176.5
ESOP, shares to be purchased	10,453,575
Loan repayments expected annual through 2036	$ 18.8
Cash dividends paid on unallocated ESOP shares		$ 3.3
Minimum age requirement to participate in ESOP		18 years
Minimum work experience within 12 months of hire needed to participate in ESOP		1000 hours
ESOP common stock allocated (in shares)		4,442,769
Unallocated common stock of Employee Stock Ownership Plan (in shares)		6,010,806		6,300,000
Fair value of deferred ESOP shares		$ 94
ESOP compensation expense		$ 4.2	$ 4.8

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail)	3 Months Ended	9 Months Ended
Fair Value Measurements - Additional Information (Detail)	Mar. 31, 2019	Sep. 30, 2019
GSE mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Maturity period of available-for-sale residential mortgage-backed securities portfolio	15 years	10 years
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount to impaired loans		10.00%

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities on Recurring Basis (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading debt securities	$ 9.3	$ 8.4
Debt securities available-for-sale, at fair value	2,978.7	3,121
Equity securities	7.8	8.1
Other assets	1,754.4	1,091.6
Derivative assets	425	103
Fair value of total assets measured at fair value on a recurring basis	3,469.9	3,296.9
Financial liabilities	78.4	139
Fair value of total liabilities measured at fair value on a recurring basis	78.4	139
Risk Participation Agreements \| Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of risk participation agreements (less than)		0.1
Exchange-traded funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	45.3	35.5
Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	3.8	20.6
Fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets		0.3
U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading debt securities	9.3	8.4
U.S. Treasury and agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale, at fair value	688.1	678
GSE mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale, at fair value	2,290.6	2,443
Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	7.8	8.1
Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	421.1	98.9
Financial liabilities	74.3	135
Interest rate caps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	2.1	3.1
Financial liabilities	2.1	3.1
Risk Participation Agreements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial liabilities	0.2	0
Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1.4	0.9
Financial liabilities	1.3	0.8
Forward commitments to sell residential mortgage loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0.4	0.1
Interest rate-lock commitments on residential mortgage loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial liabilities	0.5	0.1
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of total assets measured at fair value on a recurring basis	754.3	750.6
Fair value of total liabilities measured at fair value on a recurring basis	0	0
Level 1 \| Exchange-traded funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	45.3	35.5
Level 1 \| Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	3.8	20.6
Level 1 \| Fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets		0
Level 1 \| U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading debt securities	9.3	8.4
Level 1 \| U.S. Treasury and agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale, at fair value	688.1	678
Level 1 \| GSE mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale, at fair value	0	0
Level 1 \| Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	7.8	8.1
Level 1 \| Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Financial liabilities	0	0
Level 1 \| Interest rate caps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Financial liabilities	0	0
Level 1 \| Risk Participation Agreements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial liabilities	0	0
Level 1 \| Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Financial liabilities	0	0
Level 1 \| Forward commitments to sell residential mortgage loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Level 1 \| Interest rate-lock commitments on residential mortgage loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial liabilities	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of total assets measured at fair value on a recurring basis	2,715.6	2,546.3
Fair value of total liabilities measured at fair value on a recurring basis	78.4	139
Level 2 \| Exchange-traded funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	0	0
Level 2 \| Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	0	0
Level 2 \| Fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets		0.3
Level 2 \| U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading debt securities	0	0
Level 2 \| U.S. Treasury and agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale, at fair value	0	0
Level 2 \| GSE mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale, at fair value	2,290.6	2,443
Level 2 \| Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	0	0
Level 2 \| Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	421.1	98.9
Financial liabilities	74.3	135
Level 2 \| Interest rate caps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	2.1	3.1
Financial liabilities	2.1	3.1
Level 2 \| Risk Participation Agreements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial liabilities	0.2	0
Level 2 \| Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1.4	0.9
Financial liabilities	1.3	0.8
Level 2 \| Forward commitments to sell residential mortgage loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0.4	0.1
Level 2 \| Interest rate-lock commitments on residential mortgage loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial liabilities	0.5	0.1
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of total assets measured at fair value on a recurring basis	0	0
Fair value of total liabilities measured at fair value on a recurring basis	0	0
Level 3 \| Exchange-traded funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	0	0
Level 3 \| Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	0	0
Level 3 \| Fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets		0
Level 3 \| U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading debt securities	0	0
Level 3 \| U.S. Treasury and agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale, at fair value	0	0
Level 3 \| GSE mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available-for-sale, at fair value	0	0
Level 3 \| Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	0	0
Level 3 \| Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Financial liabilities	0	0
Level 3 \| Interest rate caps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Financial liabilities	0	0
Level 3 \| Risk Participation Agreements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial liabilities	0	0
Level 3 \| Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Financial liabilities	0	0
Level 3 \| Forward commitments to sell residential mortgage loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Level 3 \| Interest rate-lock commitments on residential mortgage loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial liabilities	$ 0	$ 0

Fair Value Measurements - Ass_2

Fair Value Measurements - Assets on Non-Recurring Basis (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale	$ 24,800,000		$ 24,800,000		$ 19,500,000
Impaired loans	48,400,000		48,400,000		55,200,000
Fair value of total assets measured at fair value on a recurring basis	3,469,900,000		3,469,900,000		3,296,900,000
Provision for loan losses	7,800,000	$ 8,200,000	21,000,000	$ 20,100,000
Repossessed assets	6,300,000		6,300,000		3,900,000
Impaired Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Provision for loan losses			5,300,000	7,700,000
REO and Repossessed Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Provision for loan losses			2,100,000	1,000,000
Nonoperating Income (Expense)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Write downs and net loss on sale of foreclosed/repossessed assets charged to non-interest expense total			(300,000)	100,000
Residential mortgage
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value adjustments			0	0
Real estate owned	12,300,000		12,300,000		5,500,000
Commercial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	35,500,000		35,500,000
Provision for loan losses	7,800,000	8,000,000	22,100,000	18,200,000
Retail
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	12,900,000		12,900,000
Provision for loan losses	0	$ 200,000	(1,100,000)	$ 1,900,000
Retail \| Residential mortgage
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	11,500,000		11,500,000		8,800,000
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of total assets measured at fair value on a recurring basis	754,300,000		754,300,000		750,600,000
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of total assets measured at fair value on a recurring basis	2,715,600,000		2,715,600,000		2,546,300,000
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of total assets measured at fair value on a recurring basis	0		0		0
Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale	24,800,000		24,800,000		19,500,000
Impaired loans	48,400,000		48,400,000		55,200,000
REO and repossessed assets	26,300,000		26,300,000		18,100,000
Fair value of total assets measured at fair value on a recurring basis	99,500,000		99,500,000		92,800,000
Nonrecurring \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale	0		0		0
Impaired loans	0		0		0
REO and repossessed assets	0		0		0
Fair value of total assets measured at fair value on a recurring basis	0		0		0
Nonrecurring \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale	24,800,000		24,800,000		19,500,000
Impaired loans	0		0		0
REO and repossessed assets	0		0		0
Fair value of total assets measured at fair value on a recurring basis	24,800,000		24,800,000		19,500,000
Nonrecurring \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale	0		0		0
Impaired loans	48,400,000		48,400,000		55,200,000
REO and repossessed assets	26,300,000		26,300,000		18,100,000
Fair value of total assets measured at fair value on a recurring basis	$ 74,700,000		$ 74,700,000		$ 73,300,000

Fair Value Measurements - Finan

Fair Value Measurements - Financial Instruments (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	$ 635.2	$ 665.7
Short-term investments	157.8	266.3
Debt securities held-to-maturity	3,805.4	3,792.3
FHLB and FRB stock	334	303.4
Time deposits	8,100.4	6,916.2
FHLB advances	2,948.5	2,404.5
Federal funds purchased	1,365	845
Customer repurchase agreements	315.6	332.9
Other borrowings	0	11
Notes and debentures	915.7	895.8
Impaired loans	48.4	55.2
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	635.2	665.7
Short-term investments	157.8	266.3
Debt securities held-to-maturity	3,805.4	3,792.3
FHLB and FRB stock	334	303.4
Total loans, net	38,487	34,945.8
Time deposits	8,100.4	6,916.2
Other deposits	30,473.1	29,242.8
FHLB advances	2,948.5	2,404.5
Federal funds purchased	1,365	845
Customer repurchase agreements	315.6	332.9
Other borrowings		11
Notes and debentures	915.7	895.8
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	635.2	665.7
Short-term investments	157.8	266.3
Debt securities held-to-maturity	3,971.5	3,775.9
FHLB and FRB stock	334	303.4
Total loans, net	38,539.2	34,606.3
Time deposits	8,120.9	6,884
Other deposits	30,473.1	29,242.8
FHLB advances	2,948.8	2,404.5
Federal funds purchased	1,365	845
Customer repurchase agreements	315.6	332.9
Other borrowings		11
Notes and debentures	936.8	893.4
Fair Value \| Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	635.2	665.7
Short-term investments	0	0
Debt securities held-to-maturity	0	0
FHLB and FRB stock	0	0
Total loans, net	0	0
Time deposits	0	0
Other deposits	0	0
FHLB advances	0	0
Federal funds purchased	0	0
Customer repurchase agreements	0	0
Other borrowings		0
Notes and debentures	0	0
Fair Value \| Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	0	0
Short-term investments	157.8	266.3
Debt securities held-to-maturity	3,970	3,774.4
FHLB and FRB stock	334	303.4
Total loans, net	9,064.9	7,806.1
Time deposits	8,120.9	6,884
Other deposits	30,473.1	29,242.8
FHLB advances	2,948.8	2,404.5
Federal funds purchased	1,365	845
Customer repurchase agreements	315.6	332.9
Other borrowings		11
Notes and debentures	936.8	893.4
Fair Value \| Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	0	0
Short-term investments	0	0
Debt securities held-to-maturity	1.5	1.5
FHLB and FRB stock	0	0
Total loans, net	29,474.3	26,800.2
Time deposits	0	0
Other deposits	0	0
FHLB advances	0	0
Federal funds purchased	0	0
Customer repurchase agreements	0	0
Other borrowings		0
Notes and debentures	$ 0	$ 0

Derivative Financial Instrume_3

Derivative Financial Instruments and Hedging Activities - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Fair value of derivative liability	$ 1,400,000
Collateral posted	800,000
Additional collateral	$ 600,000
Treasury Forward Interest Rate Locks (T-Locks)
Derivative [Line Items]
Period hedged items affected earnings, years	10 years
Derivative instruments hedge description	to hedge the risk that the 10-year U.S. Treasury yield would rise
Unrealized gain (loss) on derivatives	$ 900,000
Treasury Forward Interest Rate Locks (T-Locks) \| Subordinated notes
Derivative [Line Items]
Senior notes issuance	500,000,000
Derivatives Designated as Hedging Instruments \| Interest rate swaps \| Cash flow \| Loans
Derivative [Line Items]
Notional amounts of derivatives	$ 210,000,000	$ 210,000,000
LIBOR basis points	one-month LIBOR
Derivatives Designated as Hedging Instruments \| Interest rate swaps \| Subordinated notes \| Fair value
Derivative [Line Items]
Notional amounts of derivatives	$ 375,000,000
LIBOR basis points	three-month LIBOR
Subordinated notes	$ 400,000,000
Basis points	1.265%

Derivative Financial Instrume_4

Derivative Financial Instruments and Hedging Activities - Schedule of Notional Amount and Fair Value (Detail) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair value, Assets	$ 425,000,000	$ 103,000,000
Financial liabilities	78,400,000	139,000,000
Forward commitments to sell residential mortgage loans
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair value, Assets	400,000	100,000
Interest rate-lock commitments on residential mortgage loans
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Financial liabilities	500,000	100,000
Derivatives Not Designated as Hedging Instruments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair value, Assets	425,000,000	103,000,000
Financial liabilities	78,400,000	139,000,000
Derivatives Not Designated as Hedging Instruments \| Forward commitments to sell residential mortgage loans
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amounts	34,800,000	9,500,000
Fair value, Assets	400,000	100,000
Financial liabilities	0	0
Derivatives Not Designated as Hedging Instruments \| Interest rate-lock commitments on residential mortgage loans
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amounts	54,900,000	13,600,000
Fair value, Assets	0	0
Financial liabilities	500,000	100,000
Derivatives Designated as Hedging Instruments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair value, Assets	0	0
Financial liabilities	0	0
Interest rate swaps \| Derivatives Not Designated as Hedging Instruments \| Commercial customers
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amounts	7,592,800,000	7,455,900,000
Fair value, Assets	416,200,000	76,300,000
Financial liabilities	700,000	102,600,000
Interest rate swaps \| Derivatives Not Designated as Hedging Instruments \| Institutional counterparties
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amounts	7,599,600,000	7,161,300,000
Fair value, Assets	4,900,000	22,600,000
Financial liabilities	73,600,000	32,400,000
Interest rate swaps \| Derivatives Designated as Hedging Instruments \| Cash flow \| Loans
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amounts	210,000,000	210,000,000
Fair value, Assets	0	0
Financial liabilities	0	0
Interest rate swaps \| Derivatives Designated as Hedging Instruments \| Subordinated notes \| Fair value
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amounts	375,000,000	375,000,000
Fair value, Assets	0	0
Financial liabilities	0	0
Interest rate caps \| Derivatives Not Designated as Hedging Instruments \| Commercial customers
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amounts	264,200,000	329,100,000
Fair value, Assets	2,100,000	600,000
Financial liabilities	0	2,500,000
Interest rate caps \| Derivatives Not Designated as Hedging Instruments \| Institutional counterparties
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amounts	264,200,000	329,100,000
Fair value, Assets	0	2,500,000
Financial liabilities	2,100,000	600,000
Risk Participation Agreements \| Derivatives Not Designated as Hedging Instruments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amounts	786,600,000	576,500,000
Fair value, Assets	0	0
Financial liabilities	200,000	0
Risk Participation Agreements \| Derivatives Not Designated as Hedging Instruments \| Maximum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair value of derivatives, net		100,000
Foreign exchange contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair value, Assets	1,400,000	900,000
Financial liabilities	1,300,000	800,000
Foreign exchange contracts \| Derivatives Not Designated as Hedging Instruments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amounts	74,800,000	145,200,000
Fair value, Assets	1,400,000	900,000
Financial liabilities	$ 1,300,000	$ 800,000

Derivative Financial Instrume_5

Derivative Financial Instruments and Hedging Activities - Impact on Income and AOCI (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Pre-Tax Gain (Loss) Recognized in Earnings	$ 14.9	$ 6.3
Amount of Pre-Tax Gain (Loss) Recognized in AOCL	2.1	(3.1)
Derivatives Not Designated as Hedging Instruments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Pre-Tax Gain (Loss) Recognized in Earnings	16.1	8.3
Derivatives Not Designated as Hedging Instruments \| Forward commitments to sell residential mortgage loans
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Pre-Tax Gain (Loss) Recognized in Earnings	0.3	0
Derivatives Not Designated as Hedging Instruments \| Interest rate-lock commitments on residential mortgage loans
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Pre-Tax Gain (Loss) Recognized in Earnings	(0.3)	0
Derivatives Not Designated as Hedging Instruments \| Interest rate swaps \| Commercial customers
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Pre-Tax Gain (Loss) Recognized in Earnings	466.8	(177.1)
Derivatives Not Designated as Hedging Instruments \| Interest rate swaps \| Institutional counterparties
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Pre-Tax Gain (Loss) Recognized in Earnings	(451.3)	184.5
Derivatives Not Designated as Hedging Instruments \| Interest rate caps \| Commercial customers
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Pre-Tax Gain (Loss) Recognized in Earnings	2	(0.7)
Derivatives Not Designated as Hedging Instruments \| Interest rate caps \| Institutional counterparties
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Pre-Tax Gain (Loss) Recognized in Earnings	(2)	0.8
Derivatives Not Designated as Hedging Instruments \| Foreign exchange contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Pre-Tax Gain (Loss) Recognized in Earnings	0.5	0.6
Derivatives Not Designated as Hedging Instruments \| Risk Participation Agreements
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Pre-Tax Gain (Loss) Recognized in Earnings	0.1	0.2
Derivatives Designated as Hedging Instruments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Pre-Tax Gain (Loss) Recognized in Earnings	(1.2)	(2)
Amount of Pre-Tax Gain (Loss) Recognized in AOCL	2.1	(3.1)
Derivatives Designated as Hedging Instruments \| Cash flow \| Interest rate-lock commitments on residential mortgage loans
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Pre-Tax Gain (Loss) Recognized in Earnings	0.1	0.1
Amount of Pre-Tax Gain (Loss) Recognized in AOCL	0	0
Derivatives Designated as Hedging Instruments \| Interest rate swaps \| Fair value
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Pre-Tax Gain (Loss) Recognized in Earnings	(0.2)	(1.8)
Derivatives Designated as Hedging Instruments \| Interest rate swaps \| Cash flow
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Pre-Tax Gain (Loss) Recognized in Earnings	(1.1)	(0.3)
Amount of Pre-Tax Gain (Loss) Recognized in AOCL	$ 2.1	$ (3.1)

Balance Sheet Offsetting - Summ

Balance Sheet Offsetting - Summary of Gross Presentation, Instruments Offset (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Offsetting Assets And Liabilities [Line Items]
Fair value, Assets	$ 425	$ 103
Financial assets, Gross Amount Recognized	6.3	26
Financial assets, Gross Amount Offset	0	0
Financial assets, Net Amount Presented	6.3	26
Financial assets, Financial Instruments	(0.4)	(15.7)
Financial assets, Collateral	0	(8.6)
Financial assets, Net Amount	5.9	1.7
Financial liabilities, Gross Amount Recognized	78.4	139
Financial liabilities, Gross Amount Recognized	77	33.8
Financial liabilities, Gross Amount Offset	0	0
Financial liabilities, Net Amount Presented	77	33.8
Financial liabilities, Financial Instruments	(0.4)	(15.7)
Financial liabilities, Collateral	(74.7)	(1.2)
Financial liabilities, Net Amount	1.9	16.9
Foreign exchange contracts
Offsetting Assets And Liabilities [Line Items]
Fair value, Assets	1.4	0.9
Financial assets, Gross Amount Offset	0	0
Financial assets, Net Amount Presented	1.4	0.9
Financial assets, Financial Instruments	0	0
Financial assets, Collateral	0	0
Financial assets, Net Amount	1.4	0.9
Financial liabilities, Gross Amount Recognized	1.3	0.8
Financial liabilities, Gross Amount Offset	0	0
Financial liabilities, Net Amount Presented	1.3	0.8
Financial liabilities, Financial Instruments	0	0
Financial liabilities, Collateral		0
Financial liabilities, Net Amount	1.3	0.8
Counterparty A \| Interest Rate Swaps/Caps
Offsetting Assets And Liabilities [Line Items]
Fair value, Assets	0	3.1
Financial assets, Gross Amount Offset	0	0
Financial assets, Net Amount Presented	0	3.1
Financial assets, Financial Instruments	0	(1.4)
Financial assets, Collateral	0	(1.7)
Financial assets, Net Amount	0	0
Financial liabilities, Gross Amount Recognized	3.2	1.4
Financial liabilities, Gross Amount Offset	0	0
Financial liabilities, Net Amount Presented	3.2	1.4
Financial liabilities, Financial Instruments	0	(1.4)
Financial liabilities, Collateral	(3.2)	0
Financial liabilities, Net Amount	0	0
Counterparty B \| Interest Rate Swaps/Caps
Offsetting Assets And Liabilities [Line Items]
Fair value, Assets	0.1	2.5
Financial assets, Gross Amount Offset	0	0
Financial assets, Net Amount Presented	0.1	2.5
Financial assets, Financial Instruments	(0.1)	(2.5)
Financial assets, Collateral	0	0
Financial assets, Net Amount	0	0
Financial liabilities, Gross Amount Recognized	7.1	3.8
Financial liabilities, Gross Amount Offset	0	0
Financial liabilities, Net Amount Presented	7.1	3.8
Financial liabilities, Financial Instruments	(0.1)	(2.5)
Financial liabilities, Collateral	(7)	(1.2)
Financial liabilities, Net Amount	0	0.1
Counterparty C \| Interest Rate Swaps/Caps
Offsetting Assets And Liabilities [Line Items]
Fair value, Assets	0.1	4.8
Financial assets, Gross Amount Offset	0	0
Financial assets, Net Amount Presented	0.1	4.8
Financial assets, Financial Instruments	(0.1)	(3.7)
Financial assets, Collateral	0	(1.1)
Financial assets, Net Amount	0	0
Financial liabilities, Gross Amount Recognized	23.8	3.7
Financial liabilities, Gross Amount Offset	0	0
Financial liabilities, Net Amount Presented	23.8	3.7
Financial liabilities, Financial Instruments	(0.1)	(3.7)
Financial liabilities, Collateral	(23.7)	0
Financial liabilities, Net Amount	0	0
Counterparty D \| Interest Rate Swaps/Caps
Offsetting Assets And Liabilities [Line Items]
Fair value, Assets	0	3.6
Financial assets, Gross Amount Offset	0	0
Financial assets, Net Amount Presented	0	3.6
Financial assets, Financial Instruments	0	(2.7)
Financial assets, Collateral	0	(0.1)
Financial assets, Net Amount	0	0.8
Financial liabilities, Gross Amount Recognized	7.6	2.7
Financial liabilities, Gross Amount Offset	0	0
Financial liabilities, Net Amount Presented	7.6	2.7
Financial liabilities, Financial Instruments	0	(2.7)
Financial liabilities, Collateral	(7.6)	0
Financial liabilities, Net Amount	0	0
Counterparty E \| Interest Rate Swaps/Caps
Offsetting Assets And Liabilities [Line Items]
Fair value, Assets	4.5	0
Financial assets, Gross Amount Offset	0	0
Financial assets, Net Amount Presented	4.5	0
Financial assets, Financial Instruments	0	0
Financial assets, Collateral	0	0
Financial assets, Net Amount	4.5	0
Financial liabilities, Gross Amount Recognized	0	16
Financial liabilities, Gross Amount Offset	0	0
Financial liabilities, Net Amount Presented	0	16
Financial liabilities, Financial Instruments	0	0
Financial liabilities, Collateral		0
Financial liabilities, Net Amount	0	16
Other Counterparties \| Interest Rate Swaps/Caps
Offsetting Assets And Liabilities [Line Items]
Fair value, Assets	0.2	11.1
Financial assets, Gross Amount Offset	0	0
Financial assets, Net Amount Presented	0.2	11.1
Financial assets, Financial Instruments	(0.2)	(5.4)
Financial assets, Collateral	0	(5.7)
Financial assets, Net Amount	0	0
Financial liabilities, Gross Amount Recognized	34	5.4
Financial liabilities, Gross Amount Offset	0	0
Financial liabilities, Net Amount Presented	34	5.4
Financial liabilities, Financial Instruments	(0.2)	(5.4)
Financial liabilities, Collateral	(33.2)	0
Financial liabilities, Net Amount	$ 0.6	$ 0

Balance Sheet Offsetting - Addi

Balance Sheet Offsetting - Additional Information (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
U.S. Treasury
Offsettting Assets and Liabilities [Line Items]
Fair value of treasury securities	$ 462.6	$ 461.3
Mortgage-Backed Securities
Offsettting Assets and Liabilities [Line Items]
Fair value of treasury securities	$ 458.2	$ 457.2

Balance Sheet Offsetting - Su_2

Balance Sheet Offsetting - Summary of Collateral Swaps (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Offsettting Assets and Liabilities [Line Items]
Total repurchase agreements, Net Amount Presented	$ 315.6	$ 332.9
Collateral Swaps
Offsettting Assets and Liabilities [Line Items]
Total resale agreements, Gross Amount Recognized	450	450
Total resale agreements, Gross Amount Offset	(450)	(450)
Total resale agreements, Net Amount Presented	0	0
Total repurchase agreements, Gross Amount Recognized	450	450
Total repurchase agreements, Gross Amount Offset	(450)	(450)
Total repurchase agreements, Net Amount Presented	$ 0	$ 0

Leases - Net Investment in Leas

Leases - Net Investment in Lease Financing Receivables (Details) $ in Millions	Sep. 30, 2019USD ($)
Leases [Abstract]
Lease payments receivable	$ 1,380
Estimated residual value of leased assets	128.4
Total	1,508.4
Plus: Deferred origination costs	13.5
Less: Unearned income	(154.4)
Total net investment in lease financing receivables	$ 1,367.5

Leases - Contractual Maturities

Leases - Contractual Maturities of Lease Financing Receivables (Details) $ in Millions	Sep. 30, 2019USD ($)
Leases [Abstract]
2019	$ 229.7
2020	454.8
2021	357.7
2022	245.2
2023	137
Later years	84
Total	$ 1,508.4

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Leases [Abstract]
Lease income	$ 30.2	$ 87.6
Lease financing receivables	17.2	49.2
Operating lease income (note 14)	$ 13	$ 38.4

Leases - Cost and Supplemental

Leases - Cost and Supplemental Information (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019
Leases [Abstract]
Operating lease cost	$ 15	$ 45.4
Variable lease cost	2	6.4
Sublease income	(0.3)	(1)
Net lease cost	16.7	50.8
Lease ROU assets	235.6	235.6		$ 248.5
Operating lease liabilities	$ 260.5	260.5		$ 268.8
Cash payments included in the measurement of lease liabilities reported in operating cash flows		45.8
Right-of-use assets obtained in exchange for lessee operating lease liabilities		$ 30.3	$ 0
Weighted average discount rate	3.28%	3.28%
Weighted average remaining lease term (in years)	7 years	7 years

Leases - Contractual Maturiti_2

Leases - Contractual Maturities of Lease Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Operating Lease Liabilities, Payments Due [Abstract]
2019	$ 15.1
2020	59.1
2021	56.7
2022	39.5
2023	28.3
Later years	102.8
Total lease payments	301.5
Less: Interest	(41)
Total lease liabilities	$ 260.5	$ 268.8
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019			$ 65.4
2020			60.1
2021			56.4
2022			37.8
2023			26.1
2024 through 2054			$ 88.5

New Accounting Standards (Detai

New Accounting Standards (Details) - USD ($) $ in Millions	Jan. 01, 2019	Jan. 01, 2018	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Summary Of Significant Accounting Policies [Line Items]
Operating lease liabilities	$ 268.8		$ 260.5
ROU assets	$ 248.5		235.6
Allowance for loan losses			$ 246	$ 244	$ 240.4	$ 238	$ 236.8	$ 234.4
Retained Earnings
Summary Of Significant Accounting Policies [Line Items]
Cumulative-effect transition adjustments		$ (37.9)
Accounting Standards Update 2016-02 \| Minimum
Summary Of Significant Accounting Policies [Line Items]
Increase in risk-based capital ratios	0.05%
Accounting Standards Update 2016-02 \| Maximum
Summary Of Significant Accounting Policies [Line Items]
Increase in risk-based capital ratios	0.10%
Accounting Standards Update 2018-02
Summary Of Significant Accounting Policies [Line Items]
Increase in risk-based capital ratios		0.11%
Accounting Standards Update 2016-13 \| Minimum
Summary Of Significant Accounting Policies [Line Items]
Increase in risk-based capital ratios			0.10%
Allowance for loan losses			$ 40
Increase in allowance for loan losses, percent			15.00%
Accounting Standards Update 2016-13 \| Maximum
Summary Of Significant Accounting Policies [Line Items]
Increase in risk-based capital ratios			0.15%
Allowance for loan losses			$ 60
Increase in allowance for loan losses, percent			25.00%

Subsequent Events (Details)

Subsequent Events (Details) shares in Millions, $ in Millions	Nov. 01, 2019USD ($)branchshares	Oct. 25, 2019USD ($)branch	Sep. 30, 2019USD ($)	Dec. 31, 2018USD ($)
Subsequent Event [Line Items]
Total loans			$ 38,535.4	$ 35,001
Total deposits			38,573.5	$ 36,159
United Financial
Subsequent Event [Line Items]
Merger-related expenses			$ 1
Subsequent Event \| United Financial
Subsequent Event [Line Items]
Business combination, transaction value	$ 723.6
Total loans	5,700
Total deposits	$ 5,700
Number of branches to be acquired \| branch	59
Business acquisition common stock shares (in shares) \| shares	44.7
Disposed of by sale \| Subsequent Event
Subsequent Event [Line Items]
Number of branches to be disposed of \| branch		8
Amount of loans disposed of		$ 104
Amount of deposits disposed of		262
Amount of assets under management disposed of		240
Minimum \| Disposed of by sale \| Subsequent Event
Subsequent Event [Line Items]
Gain on disposal		9
Maximum \| Disposed of by sale \| Subsequent Event
Subsequent Event [Line Items]
Gain on disposal		$ 10