0001628280-26-042799 | 11-K | XBRL Viewer

Related Parties and Exempt Party-In-Interest	12 Months Ended
Dec. 31, 2025
EBP 005
EBP, Related Party and Party-in-Interest Transactions [Line Items]
Related Parties and Exempt Party-In-Interest	Related Parties and Exempt Party-In-Interest As of December 31, 2025 and 2024, the Plan had investments in 8,935,911 and 9,110,901 common shares of Eversource (within the Eversource Common Shares Fund and ESOP Allocated Eversource Energy Common Shares), respectively, with a cost basis of $472.1 million and $466.7 million, respectively. During the years ended December 31, 2025 and 2024, the Eversource Common Shares Fund purchased $75.1 million and $55.5 million of Eversource common shares, respectively, and sold $85.1 million and $82.1 million of Eversource common shares, respectively. For the years ended December 31, 2025 and 2024, the Plan recorded dividend income on common shares of Eversource of $25.8 million and $25.3 million, respectively. Certain Plan investments are shares of registered investment companies managed by the Trustee. Therefore, these transactions qualify as exempt party-in-interest transactions. Fees paid by the Plan for the investment management services amounted to $1.0 million and $0.8 million for the years ended December 31, 2025 and 2024, respectively. Transactions under the Plan's revenue sharing agreement with the Trustee (see Note 4) qualify as exempt party-in-interest transactions. Amounts earned under this revenue sharing agreement were $1.0 million and $3.0 million for the years ended December 31, 2025 and 2024, respectively, of which $0.6 million for each of the years ended were used to pay eligible plan expenses.

Tax Status	12 Months Ended
Dec. 31, 2025
EBP 005
EBP, Tax Status [Line Items]
Tax Status	Tax Status The IRS has determined, and informed the Company by a letter dated February 6, 2023, that the Plan and related trust are designed in accordance with applicable sections of the IRC. Although the Plan has been amended since receiving the determination letter, the Administrator and the Plan's tax counsel believe that the Plan is designed and is currently being operated in compliance with the applicable requirements of the IRC and that the related trust continues to be tax-exempt. Therefore, no provision for income taxes has been included in the Plan's financial statements. The Plan is subject to routine audits by taxing jurisdictions; however, there are currently no audits for any tax periods in progress. The Plan is no longer subject to income tax examinations for years prior to 2022.

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2025

EBP, Investment, Fair Value and NAV [Line Items]

The following tables summarize the fair values and levels within the fair value hierarchy:


Fair Value Measurements as of December 31, 2025
(Thousands of Dollars)	Level 1		Level 2		Uncategorized		Total
Investments at Fair Value
Common Collective Trusts	$	—	$	—	$	2,709,815	$	2,709,815
Eversource Common Shares Fund	585,652		—		—		585,652
ESOP Allocated Eversource Energy Common Shares	15,764		—		—		15,764
Registered Investment Companies	281,168		—		—		281,168
Investments Held by Brokerage Link	269,639		13,218		—		282,857
Separately Managed Account	78,021		—		—		78,021

Cash and Cash Equivalents	60,667		—		—		60,667
Total Investments at Fair Value	$	1,290,911	$	13,218	$	2,709,815	$	4,013,944


Fair Value Measurements as of December 31, 2024
(Thousands of Dollars)	Level 1		Level 2		Uncategorized		Total
Investments at Fair Value
Common Collective Trusts	$	—	$	—	$	2,334,587	$	2,334,587
Eversource Common Shares Fund	508,278		—		—		508,278
ESOP Allocated Eversource Energy Common Shares	14,698		—		—		14,698
Registered Investment Companies	286,174		—		—		286,174
Investments Held by Brokerage Link	233,554		12,448		—		246,002
Separately Managed Account	93,636		—		—		93,636
Cash and Cash Equivalents	45,726		—		—		45,726
Total Investments at Fair Value	$	1,182,066	$	12,448	$	2,334,587	$	3,529,101

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details

- Definition

Tabular disclosure of fair value of investment held by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), including, but not limited to, fair value measured at net asset value per share as practical expedient (NAV).

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+ Details

Risks and Uncertainties	12 Months Ended
Dec. 31, 2025
EBP 005
EBP, Risk and Uncertainty [Line Items]
Risks and Uncertainties	Risks and Uncertainties The Plan provides for various investment options in a combination of investment securities. Investment securities are exposed to various risks including, but not limited to, interest rates, market conditions and credit risks. Due to the level of risk associated with certain investment securities and the level of uncertainty related to changes in the value of investment securities, it is at least reasonably possible that changes in the values of investment securities will occur in the near term and that such changes could materially affect participants’ account balances and the amounts reported in the Statements of Net Assets Available for Benefits in future periods. The Plan has invested a significant portion of its assets in the Eversource Common Shares Fund. This investment in the Eversource Common Shares Fund approximates 13 percent of the Plan’s net assets available for benefits as of both December 31, 2025 and 2024. As a result of this concentration, any significant fluctuation in the market value of the Eversource Common Shares Fund could affect individual participant accounts and the net assets of the Plan.

Summary of Significant Accounting Policies (Details) - EBP 005 - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	$ 4,432,723
Investment, at contract value	418,779	$ 465,481
Investment, Identifier [Axis]: Boston Trust Walden \| Acuity Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,020
Investment, Identifier [Axis]: Boston Trust Walden \| Akamai Technologies, Inc.
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	649
Investment, Identifier [Axis]: Boston Trust Walden \| Allegion Plc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,497
Investment, Identifier [Axis]: Boston Trust Walden \| Amdocs Ltd
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,013
Investment, Identifier [Axis]: Boston Trust Walden \| American Financial Group Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	988
Investment, Identifier [Axis]: Boston Trust Walden \| Antero Midstream Corp
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,148
Investment, Identifier [Axis]: Boston Trust Walden \| Applied Industrial Tech Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,170
Investment, Identifier [Axis]: Boston Trust Walden \| Aptargroup Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,326
Investment, Identifier [Axis]: Boston Trust Walden \| Atmos Energy Corp
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	879
Investment, Identifier [Axis]: Boston Trust Walden \| Avery Dennison Corp
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,018
Investment, Identifier [Axis]: Boston Trust Walden \| BJ's Wholesale Club Holdings
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,484
Investment, Identifier [Axis]: Boston Trust Walden \| Badger Meter Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	721
Investment, Identifier [Axis]: Boston Trust Walden \| CBOE Holdings Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,340
Investment, Identifier [Axis]: Boston Trust Walden \| Camden Property Trust
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	940
Investment, Identifier [Axis]: Boston Trust Walden \| Cavco Industries Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	770
Investment, Identifier [Axis]: Boston Trust Walden \| Charles River Laboratories Intl Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,181
Investment, Identifier [Axis]: Boston Trust Walden \| Check Point Software Tech Ltord
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,289
Investment, Identifier [Axis]: Boston Trust Walden \| Chemed Corp
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	918
Investment, Identifier [Axis]: Boston Trust Walden \| Choice Hotels Intl Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	896
Investment, Identifier [Axis]: Boston Trust Walden \| Cincinnati Financial Corp
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,497
Investment, Identifier [Axis]: Boston Trust Walden \| Commerce Bancshares Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	960
Investment, Identifier [Axis]: Boston Trust Walden \| Cooper Cos Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,385
Investment, Identifier [Axis]: Boston Trust Walden \| CubeSmart
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	779
Investment, Identifier [Axis]: Boston Trust Walden \| Cullen/Frost Bankers Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,224
Investment, Identifier [Axis]: Boston Trust Walden \| Dolby Laboratories Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	534
Investment, Identifier [Axis]: Boston Trust Walden \| Donaldson Co Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,362
Investment, Identifier [Axis]: Boston Trust Walden \| Dynatrace Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	914
Investment, Identifier [Axis]: Boston Trust Walden \| EXL Service Holdings Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,032
Investment, Identifier [Axis]: Boston Trust Walden \| East West Bancorp Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,050
Investment, Identifier [Axis]: Boston Trust Walden \| Essential Utils Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,227
Investment, Identifier [Axis]: Boston Trust Walden \| Expeditors Intl Wash Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,287
Investment, Identifier [Axis]: Boston Trust Walden \| F5 Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	986
Investment, Identifier [Axis]: Boston Trust Walden \| FactSet Resh Systems Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	933
Investment, Identifier [Axis]: Boston Trust Walden \| Genuine Parts Co
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	528
Investment, Identifier [Axis]: Boston Trust Walden \| Globus Medical Inc-A
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,275
Investment, Identifier [Axis]: Boston Trust Walden \| GoDaddy Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	866
Investment, Identifier [Axis]: Boston Trust Walden \| Hubbell Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,248
Investment, Identifier [Axis]: Boston Trust Walden \| IDACORP Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	617
Investment, Identifier [Axis]: Boston Trust Walden \| IDEX Corp Com
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,529
Investment, Identifier [Axis]: Boston Trust Walden \| International Bancshares Crp
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	616
Investment, Identifier [Axis]: Boston Trust Walden \| Jack Henry & Associates Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,168
Investment, Identifier [Axis]: Boston Trust Walden \| Jazz Pharmaceuticals Plc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	698
Investment, Identifier [Axis]: Boston Trust Walden \| Jones Lang Lasalle Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,538
Investment, Identifier [Axis]: Boston Trust Walden \| Lamar Advertising Co
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	800
Investment, Identifier [Axis]: Boston Trust Walden \| Lincoln Electric Holdings
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	941
Investment, Identifier [Axis]: Boston Trust Walden \| Magnolia Oil & Gas Corp
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,518
Investment, Identifier [Axis]: Boston Trust Walden \| Masco Corp Com
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	681
Investment, Identifier [Axis]: Boston Trust Walden \| Matador Resources Co
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	554
Investment, Identifier [Axis]: Boston Trust Walden \| McCormick & Co Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,109
Investment, Identifier [Axis]: Boston Trust Walden \| Medpace Holdings Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,502
Investment, Identifier [Axis]: Boston Trust Walden \| NetApp Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	880
Investment, Identifier [Axis]: Boston Trust Walden \| New York Times Co
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,297
Investment, Identifier [Axis]: Boston Trust Walden \| Nordson Corporation
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,547
Investment, Identifier [Axis]: Boston Trust Walden \| Northern Trust Corporation
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	855
Investment, Identifier [Axis]: Boston Trust Walden \| One Gas Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	732
Investment, Identifier [Axis]: Boston Trust Walden \| Paycom Software Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	924
Investment, Identifier [Axis]: Boston Trust Walden \| Progress Software Corp
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	718
Investment, Identifier [Axis]: Boston Trust Walden \| Qualys Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,542
Investment, Identifier [Axis]: Boston Trust Walden \| RPM International Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,154
Investment, Identifier [Axis]: Boston Trust Walden \| SEI Investments Company
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,484
Investment, Identifier [Axis]: Boston Trust Walden \| Separately Managed Account
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	78,021
Investment, Identifier [Axis]: Boston Trust Walden \| Service Corp International
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,270
Investment, Identifier [Axis]: Boston Trust Walden \| Silgan Holdings Inc.
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	475
Investment, Identifier [Axis]: Boston Trust Walden \| Simply Good Foods Co
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	540
Investment, Identifier [Axis]: Boston Trust Walden \| Smith (A.O.) Corp
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,287
Investment, Identifier [Axis]: Boston Trust Walden \| Snap On Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,344
Investment, Identifier [Axis]: Boston Trust Walden \| Sprouts Farmers Market Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	649
Investment, Identifier [Axis]: Boston Trust Walden \| Stag Industrial Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	736
Investment, Identifier [Axis]: Boston Trust Walden \| Steris Plc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,459
Investment, Identifier [Axis]: Boston Trust Walden \| Teradyne Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,593
Investment, Identifier [Axis]: Boston Trust Walden \| Texas Roadhouse Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	841
Investment, Identifier [Axis]: Boston Trust Walden \| TopBuild Corp
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,197
Investment, Identifier [Axis]: Boston Trust Walden \| Watts Water Technologies
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	1,063
Investment, Identifier [Axis]: Boston Trust Walden \| Williams-Sonoma Inc
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	861
Investment, Identifier [Axis]: Boston Trust Walden \| Zebra Technologies Corp
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	968
Investment, Identifier [Axis]: EARNEST Partners \| Interest in Common Collective Trust
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	78,834
Investment, Identifier [Axis]: Eversource Energy \| Cash and Cash Equivalents
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	60,667
Investment, Identifier [Axis]: Eversource Energy \| Eversource Common Shares Fund (including the ESOP allocated Eversource Energy Common Shares), $5 par
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	601,416
Investment, Identifier [Axis]: Fidelity \| FIAM U.S. Bond Index Commingled Pool Class C
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	26,219
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2010 Commingled Pool Class Y
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	12,259
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2015 Commingled Pool Class Y
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	341
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2020 Commingled Pool Class Y
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	112,170
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2025 Commingled Pool Class Y
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	7,334
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2030 Commingled Pool Class Y
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	297,627
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2035 Commingled Pool Class Y
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	16,642
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2040 Commingled Pool Class Y
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	275,394
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2045 Commingled Pool Class Y
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	10,805
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2050 Commingled Pool Class Y
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	224,053
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2055 Commingled Pool Class Y
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	7,362
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2060 Commingled Pool Class Y
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	102,854
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2065 Commingled Pool Class Y
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	2,758
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2070 Commingled Pool Class Y
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	745
Investment, Identifier [Axis]: Fidelity \| Freedom Blend Retirement Commingled Pool Class Y
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	10,861
Investment, Identifier [Axis]: Fidelity \| Growth Company Commingled Pool Class F
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	704,902
Investment, Identifier [Axis]: Fidelity \| International Discovery Fund – Class K
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	106,564
Investment, Identifier [Axis]: Fidelity \| Spartan 500 Index Pool Class E
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	636,122
Investment, Identifier [Axis]: Fidelity \| Spartan Extended Market Index Pool Class E
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	21,154
Investment, Identifier [Axis]: Fidelity \| Spartan Global ex US Index Pool Class E
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	64,438
Investment, Identifier [Axis]: IR+M \| Intermediate Bond Fund - Common Collective Trust
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	96,942
Investment, Identifier [Axis]: Prudential \| Investment Contract
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	418,779
Investment, Identifier [Axis]: Vanguard \| Windsor II Admiral
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	174,603
Investment, Identifier [Axis]: Various \| Brokerage Link
EBP, Accounting Policy [Line Items]
Assets held for investment, contract value	$ 282,857

Related Parties and Exempt Party-In-Interest (Details) - EBP 005 - USD ($)	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
EBP, Related Party and Party-in-Interest Transactions [Line Items]
Investment at fair value	$ 4,013,944,000	$ 3,529,101,000
Administrative expenses	$ 1,646,000	$ 1,405,000
EBP, Employer, Common Stock
EBP, Related Party and Party-in-Interest Transactions [Line Items]
Number of shares (in shares)	8,935,911	9,110,901
Investment at fair value	$ 472,100,000	$ 466,700,000
Investment cost	75,100,000	55,500,000
Investment selling price	85,100,000	82,100,000
Dividend income investment	25,800,000	25,300,000
Administrative expenses	1,000,000.0	800,000
Revenue sharing agreement, income	1,000,000.0	3,000,000.0
Revenue sharing agreement, expense	$ 600,000	$ 600,000

Summary of Significant Accounting Policies (Policies) - EBP 005	12 Months Ended
	Dec. 31, 2025
EBP, Accounting Policy [Line Items]
Basic of Accounting	The financial statements have been prepared on the accrual basis of accounting in accordance with accounting principles generally accepted in the United States of America (GAAP). The following is a summary of the significant accounting policies used.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents include cash on hand and short-term cash investments that are highly liquid in nature and have original maturities of three months or less.
Plan Estimates	Plan Estimates The preparation of financial statements in conformity with GAAP requires Plan management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, as well as the reported amounts of changes in net assets during the reporting period. Actual results could differ from those estimates.
Investments	Investments The Plan has investment options for participants, which invest in various securities including common collective trusts, registered investment companies, common stock, exchange-traded funds, certificates of deposit, corporate debt instruments, government bonds, preferred stock, and Eversource common shares. Plan investments are stated at fair value (with the exception of the Investment Contract Held by Insurance Company, which is stated at contract value, as discussed below). The fair value of Eversource common shares, investments in registered investment companies, certain assets in the self-directed Brokerage Link account, and equity securities within a separately managed account are based on the closing prices reported on active or non-active markets. Effective December 2024, the Plan Sponsor implemented changes to the Plan’s investment lineup to reduce overall investment management fees for the Plan and Plan participants. As part of this initiative, certain mutual fund options were replaced with lower-cost institutional alternatives. This includes the Fidelity Freedom target date mutual funds, which were replaced by the Fidelity Freedom Blend target date common collective trusts. These common collective trusts are managed by Fidelity and are designed to provide similar investment objectives and risk profiles as the replaced mutual funds, while offering reduced expense ratios. Certain other mutual funds previously classified as Registered Investment Companies were replaced with common stock held in a Separately Managed Account, which includes individual securities that are owned by the Plan but are managed on the participant's behalf. Separately Managed Accounts are considered individual investments for accounting and financial reporting purposes. Additionally, the United States government securities and corporate debt instruments in the Intermediate Bond Fund were replaced by a lower cost common collective trust with a similar investment strategy. Other investment options were reviewed and, where appropriate, replaced with lower-cost share classes or common collective trusts. These changes were made in the best interest of Plan participants and are expected to result in lower overall investment-related expenses. The accompanying Statements of Changes in Net Assets Available for Benefits include the net appreciation and depreciation in the fair value of investments, which consist of the realized gains and losses, the unrealized appreciation and depreciation, less investment expenses pertaining to those investments. Dividend income is recorded on the ex-dividend date, and interest income is recorded as earned. Purchases and sales of securities are recorded as of the trade date. Investment securities, in general, are exposed to various risks, such as interest rate risk, credit risk, and overall market volatility. Due to the level of risk associated with certain investment securities, it is reasonably possible that changes in the values of investment securities will occur in the near term, which could materially affect the amounts reported in the financial statements. Investment Contract Held by Insurance Company and Wrapper Contract: This contract with The Prudential Insurance Company of America (Prudential) is comprised of a mixture of government and non-government bonds, managed to the Barclays Capital Intermediate Government Credit Index, which are placed in a trust (with ownership by the Plan) rather than a separate account of the issuer. The contract is fully benefit-responsive and provides that participants must execute plan transactions at contract value and insures the underlying assets at contract value. The underlying assets of the contract are managed by Pacific Investment Management Company, LLC (PIMCO) and Jennison Associates and had a contract value of $418.8 million and $465.5 million as of December 31, 2025 and 2024, respectively. There are no reserves against contract value for credit risk of the contract issuance or otherwise. Management believes that the occurrence of events that would cause the Plan to transact at less than contract value is not probable. Prudential may not terminate the contract at any amount less than contract value.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Plan applies Accounting Standards Codification (ASC) 820, Fair Value Measurement and Disclosures (ASC 820), for all applicable financial assets and liabilities and nonfinancial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis. ASC 820 defines fair value, establishes a fair value hierarchy, and includes disclosures about fair value measurements. ASC 820 defines fair value as the price that would be received upon sale of an asset or paid upon transfer of a liability in an orderly transaction between market participants at the measurement date and in the principal or most advantageous market for that asset or liability.

- Definition

Disclosure of accounting policy for use of estimate in preparation of financial statement of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References + Details

Employee Benefit Plan, Statement of Net Asset Available for Benefit (Statement) - EBP 005 - USD ($)	Dec. 31, 2025	Dec. 31, 2024
Assets:
Total Investments, at Fair Value	$ 4,013,944,000	$ 3,529,101,000
Investments, at Contract Value:	418,779,000	465,481,000
Total Investments	4,432,723,000	3,994,582,000
EBP, Receivable [Abstract]
Notes Receivable from Participants	47,100,000	44,342,000
Participant Contributions	4,598,000	4,930,000
Employer Contributions	1,643,000	1,830,000
Other Receivables	264,000	663,000
Total Receivables	53,605,000	51,765,000
Net Assets Available for Benefits	4,486,328,000	4,046,347,000
Common Collective Trusts
Assets:
Total Investments, at Fair Value	2,709,815,000	2,334,587,000
Eversource Common Shares Fund
Assets:
Total Investments, at Fair Value	585,652,000	508,278,000
ESOP Allocated Eversource Energy Common Shares
Assets:
Total Investments, at Fair Value	15,764,000	14,698,000
Registered Investment Companies
Assets:
Total Investments, at Fair Value	281,168,000	286,174,000
Investments Held by Brokerage Link
Assets:
Total Investments, at Fair Value	282,857,000	246,002,000
Separately Managed Account
Assets:
Total Investments, at Fair Value	78,021,000	93,636,000
Cash and Cash Equivalents
Assets:
Total Investments, at Fair Value	$ 60,667,000	$ 45,726,000

Plan Description

12 Months Ended

Dec. 31, 2025

EBP 005

EBP, Description of Plan [Line Items]

Plan Description

Eversource Energy Service Company (Eversource Service), on its behalf and that of other participating subsidiaries of Eversource Energy (Eversource) (together, the Company), established the Eversource 401k Plan (the Plan) on January 1, 1985, to provide a convenient method for Company employees to save for their retirement on a regular and long-term basis. The following is a brief description of the Plan, which is provided for general information purposes only. Participants should refer to the Plan document for a more complete description of the Plan's provisions.

General

The Plan is a qualified defined contribution plan subject to the rules and regulations of the Employee Retirement Income Security Act of 1974 (ERISA) that consists of two components: a profit-sharing plan qualified under Section 401(a) of the Internal Revenue Code (IRC) with a cash or deferred arrangement under Section 401(k) of the IRC, and an Employee Stock Ownership Plan (ESOP) within the meaning of Section 4975(e)(7) of the IRC designed to invest primarily in Eversource common shares and intended to qualify under Section 401(a) of the IRC as a stock bonus plan. The participants have the option of receiving distributions upon retirement or termination of employment in the form of cash, in-kind rollovers for Fidelity funds, or Eversource common shares, to the extent so invested. Participants may roll over all, or a portion of their Plan balances into an individual retirement account (IRA) or other accepting employer qualified plan and may receive distributions in cash through in-service withdrawals of certain amounts.

The Plan is administered by the Executive Vice President – Human Resources and Information Technology of the Company (the Administrator), who determines eligibility in accordance with Plan documents and makes other interpretations under the Plan at her discretion in conjunction with the Eversource Plan Administration Committee. The fiduciaries with respect to the Plan are the Administrator, Eversource Service (the Plan sponsor), the Eversource Retirement Plan and Investment Committee, and the Plan Trustee, as defined below. The Board of Eversource Service is responsible for determining who has the authority to amend and terminate the Plan and certain other duties. The Eversource Retirement Plan and Investment Committee is responsible for establishing and implementing Plan investment policies, selecting investment fund options available to participants under the Plan, and monitoring the performance and operations of Plan investment managers and the Plan Trustee.

Plan investment assets are held in a trust by Fidelity Management Trust Company (Fidelity) (the Trustee). Plan records are maintained by an affiliate of the Trustee, Fidelity Investments Institutional Operations Company, Inc., the Plan recordkeeper. The Trustee retains the Plan assets and makes distributions as instructed by the Administrator or its designee. The Eversource Retirement Plan and Investment Committee is responsible for appointing and removing the Trustee.

Under the Plan, employees may authorize payroll deductions for contributions to the Plan. An employer matching contribution to the Plan is provided in Eversource common shares (see Contributions, below). The allocation of Eversource common shares to a participant's account may be made from a combination of Eversource treasury shares and open market repurchases of Eversource common shares.

TRAESOP/PAYSOP

In 1992, the Plan was amended to provide for the merger into the Plan, of the Eversource Service Tax Reduction Act Employee Stock Ownership Plan (TRAESOP) and the Eversource Service Payroll-Based Employee Stock Ownership Plan (PAYSOP) Fund, which were two ESOPs for which the applicable tax credits had expired. Participants' accounts under the TRAESOP and PAYSOP are maintained as separate participant accounts under the Plan.

Dividends

Participants who have holdings in the Eversource Common Shares Fund and/or the TRAESOP/PAYSOP Fund in their Plan account can elect to receive dividends paid by these funds on Eversource common shares in cash or continue to have them reinvested automatically in the Plan by allocation of Eversource common shares of equal value. If a participant holds each of the Eversource share funds, the dividend distribution election applies to all funds. If no active election is made, dividends will continue to be reinvested.

Contributions

Participant Contributions: Under the Plan, active participants may contribute on a pre-tax basis, an after-tax basis, a Roth 401k basis, or a combination of the three, as defined in the Plan document, and as subject to annual Internal Revenue Service (IRS) dollar limitations. Employees who have not enrolled in the Plan within 60 days from their date of hire, are automatically enrolled in the Plan at an employee-contribution rate of three percent of pre-tax eligible earnings, subject to their modification at any time. Participants may also disenroll and not participate at anytime.

All contributions are invested by the Trustee, as directed by each participant, in one or more investment options of the Plan, including the Eversource Common Shares Fund. In 2025 and 2024, the maximum combined participant contribution was the lesser of $23,500 and $23,000, respectively, or 50 percent of a participant's pre-tax annual compensation up to the annual IRS dollar limitations. For individuals who are age 50 or older during the 2025 and 2024 calendar years, a pre-tax and/or Roth 401k catch-up contribution of an additional $7,500 per year was permitted. Effective in 2025 and 2026, individuals who are between the ages of 60 and 63 are eligible to make pre-tax and/or Roth 401k catch-up contributions of an additional $11,250 per year.

Plan participants direct their contributions among various investment options, as specified within the Plan documents.

Employer Contributions: Effective January 1, 2025 for eligible Plan participants, the Eversource 401k Plan provided employer matching contributions of 100 percent up to a maximum of six percent of eligible compensation. For certain eligible newly hired employees, depending on union status, the six-month initial wait period to receive employer matching contributions was also eliminated. During 2024 and prior, the Plan provided employer matching contributions to eligible employees participating in the Plan of either 100 percent up to a maximum of three percent of eligible compensation or 50 percent up to a maximum of eight percent of eligible compensation. For newly hired employees with at least six months of service, the Plan provided employer matching contributions of 100 percent up to a maximum of three percent of eligible compensation, contributed on a pre-tax and/or Roth 401k basis for each employee, as applicable, while employees with less than six months of service received no employer match contribution.

The employer matching contributions are made into the Eversource Common Shares Fund. The majority of participants are permitted to immediately diversify out of the Eversource Common Shares Fund into other funds within the Plan.

A participant is fully vested in his or her own contributions, as well as earnings thereon, immediately upon making the contribution. Participants are also immediately vested in employer matching contributions plus actual earnings thereon.

K-Vantage Contributions: Prior to 2025, the Plan provided an enhanced non-elective Company contribution feature (referred to as K-Vantage), for eligible employees, as defined in the Plan document.

Eligible participants automatically received K-Vantage contributions to their Plan account, made on a payroll basis. The K-Vantage contribution was based on age and years of service as of each January 1st and was the amount of the participant's applicable Plan compensation, as defined by the Plan, multiplied by the applicable percentage, according to the following formula:



Sum of Age and Service Years as of January 1st			Company Contribution
Less than 40 years			2.5% of Plan compensation
40 through 59 years			4.5% of Plan compensation
60 years and greater			6.5% of Plan compensation

Participants who were eligible for K-Vantage became fully vested in K-Vantage contributions plus actual earnings thereon after 3 years of service. Upon a termination of the Plan, all affected participants become vested in these contributions in their accounts, including K-Vantage. Prior to a Plan termination, K-Vantage participants become immediately vested upon: (a) death while an active employee or (b) disability of the participant.

Effective January 1, 2025, a Cash Balance Pension Plan was established, which replaced employer K-Vantage contributions. Eversource transferred non-represented and represented K-Vantage employees, as negotiated, into the Cash Balance Pension Plan (with the exception of one union group that voted to enter the Cash Balance Pension Plan effective January 1, 2026), and provides participants with annual credits as of each December 31st as a set percentage of an employee’s eligible pay based on age and years of service on the employee’s behalf. This benefit is a new, additional obligation of the existing Eversource Pension Plan and is funded through the existing assets of the Eversource Pension Plan.

For active eligible K-Vantage employees that were not vested in K-Vantage prior to migrating to the Eversource Cash Balance Pension Plan on January 1, 2025, their prior K-Vantage accrued service will subsequently carry forward to the Eversource Cash Balance Pension Plan, with vesting in both K-Vantage and in the Eversource Cash Balance Pension Plan occurring in the aggregate. Effective January 1, 2025, no additional K-Vantage contributions were made to the Plan with the exception of one union that had not yet adopted the Eversource Cash Balance Pension Plan as a replacement for K-Vantage.

Forfeitures

As of December 31, 2025 and 2024, investments in the Fixed Income Fund include $46,518 and $27,342, respectively, of forfeitures that may be used to offset future Company contributions to the Plan. These forfeitures resulted from participants who were not yet vested in their K-Vantage account upon termination of employment. During 2025 and 2024, the Company used $1.0 million and $1.3 million, respectively, of forfeitures to offset Company contributions to the Plan.

Benefits

Following termination or retirement from the Company, the participant has several options: participants may defer receipt of any balance in their account up to the time they attain age 73 (or older as indexed by law) if their account balance is greater than $1,000, at which point they must begin to receive required minimum distributions (if the balance is less than $1,000, the account will be liquidated unless the participant elects to initiate a direct rollover to another qualified plan or IRA); they can initiate a direct rollover of all or a portion of their account in the Plan to another qualified plan or IRA; they can request a lump sum disbursement, or they can initiate automatic withdrawal payments. Participants who have terminated employment may also take partial distributions. In-service withdrawals and loans are permitted if certain criteria are met.

Participant Accounts

Individual accounts are maintained for Plan participants to reflect each participant's share of the Company's contribution, the participant's contribution, and applicable income from the underlying investment funds according to the participant's investment of his or her own account. Allocations of income are determined at the participant account level.

Notes Receivable from Participants

Subject to certain limitations, participants may apply for up to two loans from their non-ESOP/non-K-Vantage account balances, up to the IRS loan limit. Interest on the loan is set at the prime rate plus one percent at the time of borrowing, and the loan is secured by the balance in the participant's account. Loans are to be repaid within six months to five years (for a general purpose loan) or up to 30 years (for a primary residence loan).

Notes receivable from participants represent participant loans that are recorded at their unpaid principal balance plus any accrued but unpaid interest. Interest income on notes receivable from participants is recorded as earned and was $3.7 million and $3.1 million for the years ended December 31, 2025 and 2024, respectively. No allowances for credit losses have been recorded as of December 31, 2025 and 2024. If a participant ceases to make loan repayments and the Administrator deems the participant loan to be a distribution, the participant loan balance is reduced and a benefit payment is recorded.

Termination Provision

Although the Company intends to continue the Plan, Eversource Service may terminate the Plan, and each participating subsidiary of Eversource may terminate its participation in the Plan for any reason, in whole or in part, by action of its Board of Directors. Upon termination of the Plan or complete discontinuance of contributions thereunder, all affected participants shall become immediately vested in their accounts, including K-Vantage. In addition, the Plan recordkeeper shall make a final allocation of employer

matching contributions and net earnings/losses to the participants after payments of all outstanding claims against the Plan have been made.

Thereafter, participants shall receive a lump sum payment no later than 60 days after the later of: (1) termination of the Plan or (2) receipt of an IRS determination letter stating that such termination does not adversely affect the qualified status of the Plan.

Employee Benefit Plan, Schedule, Asset Held for Investment (Details) - EBP 005 - USD ($)	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
EBP, Schedule of Asset Held for Investment [Line Items]
Entity tax identification number	06-0810627
Plan number	005
Assets held for investment, contract value	$ 4,432,723,000
Participate loan, after deemed distribution	47,100,000
Assets held for investment	4,479,823,000
Notes Receivable from Participants	$ 47,100,000	$ 44,342,000
Minimum
EBP, Schedule of Asset Held for Investment [Line Items]
Participant loan, interest rate	3.25%
Maximum
EBP, Schedule of Asset Held for Investment [Line Items]
Participant loan, interest rate	9.50%
Investment, Identifier [Axis]: Boston Trust Walden \| Acuity Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	$ 1,020,000
Investment, Identifier [Axis]: Boston Trust Walden \| Akamai Technologies, Inc.
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	649,000
Investment, Identifier [Axis]: Boston Trust Walden \| Allegion Plc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,497,000
Investment, Identifier [Axis]: Boston Trust Walden \| Amdocs Ltd
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,013,000
Investment, Identifier [Axis]: Boston Trust Walden \| American Financial Group Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	988,000
Investment, Identifier [Axis]: Boston Trust Walden \| Antero Midstream Corp
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,148,000
Investment, Identifier [Axis]: Boston Trust Walden \| Applied Industrial Tech Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,170,000
Investment, Identifier [Axis]: Boston Trust Walden \| Aptargroup Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,326,000
Investment, Identifier [Axis]: Boston Trust Walden \| Atmos Energy Corp
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	879,000
Investment, Identifier [Axis]: Boston Trust Walden \| Avery Dennison Corp
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,018,000
Investment, Identifier [Axis]: Boston Trust Walden \| BJ's Wholesale Club Holdings
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,484,000
Investment, Identifier [Axis]: Boston Trust Walden \| Badger Meter Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	721,000
Investment, Identifier [Axis]: Boston Trust Walden \| CBOE Holdings Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,340,000
Investment, Identifier [Axis]: Boston Trust Walden \| Camden Property Trust
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	940,000
Investment, Identifier [Axis]: Boston Trust Walden \| Cavco Industries Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	770,000
Investment, Identifier [Axis]: Boston Trust Walden \| Charles River Laboratories Intl Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,181,000
Investment, Identifier [Axis]: Boston Trust Walden \| Check Point Software Tech Ltord
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,289,000
Investment, Identifier [Axis]: Boston Trust Walden \| Chemed Corp
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	918,000
Investment, Identifier [Axis]: Boston Trust Walden \| Choice Hotels Intl Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	896,000
Investment, Identifier [Axis]: Boston Trust Walden \| Cincinnati Financial Corp
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,497,000
Investment, Identifier [Axis]: Boston Trust Walden \| Commerce Bancshares Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	960,000
Investment, Identifier [Axis]: Boston Trust Walden \| Cooper Cos Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,385,000
Investment, Identifier [Axis]: Boston Trust Walden \| CubeSmart
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	779,000
Investment, Identifier [Axis]: Boston Trust Walden \| Cullen/Frost Bankers Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,224,000
Investment, Identifier [Axis]: Boston Trust Walden \| Dolby Laboratories Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	534,000
Investment, Identifier [Axis]: Boston Trust Walden \| Donaldson Co Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,362,000
Investment, Identifier [Axis]: Boston Trust Walden \| Dynatrace Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	914,000
Investment, Identifier [Axis]: Boston Trust Walden \| EXL Service Holdings Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,032,000
Investment, Identifier [Axis]: Boston Trust Walden \| East West Bancorp Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,050,000
Investment, Identifier [Axis]: Boston Trust Walden \| Essential Utils Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,227,000
Investment, Identifier [Axis]: Boston Trust Walden \| Expeditors Intl Wash Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,287,000
Investment, Identifier [Axis]: Boston Trust Walden \| F5 Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	986,000
Investment, Identifier [Axis]: Boston Trust Walden \| FactSet Resh Systems Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	933,000
Investment, Identifier [Axis]: Boston Trust Walden \| Genuine Parts Co
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	528,000
Investment, Identifier [Axis]: Boston Trust Walden \| Globus Medical Inc-A
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,275,000
Investment, Identifier [Axis]: Boston Trust Walden \| GoDaddy Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	866,000
Investment, Identifier [Axis]: Boston Trust Walden \| Hubbell Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,248,000
Investment, Identifier [Axis]: Boston Trust Walden \| IDACORP Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	617,000
Investment, Identifier [Axis]: Boston Trust Walden \| IDEX Corp Com
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,529,000
Investment, Identifier [Axis]: Boston Trust Walden \| International Bancshares Crp
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	616,000
Investment, Identifier [Axis]: Boston Trust Walden \| Jack Henry & Associates Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,168,000
Investment, Identifier [Axis]: Boston Trust Walden \| Jazz Pharmaceuticals Plc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	698,000
Investment, Identifier [Axis]: Boston Trust Walden \| Jones Lang Lasalle Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,538,000
Investment, Identifier [Axis]: Boston Trust Walden \| Lamar Advertising Co
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	800,000
Investment, Identifier [Axis]: Boston Trust Walden \| Lincoln Electric Holdings
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	941,000
Investment, Identifier [Axis]: Boston Trust Walden \| Magnolia Oil & Gas Corp
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,518,000
Investment, Identifier [Axis]: Boston Trust Walden \| Masco Corp Com
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	681,000
Investment, Identifier [Axis]: Boston Trust Walden \| Matador Resources Co
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	554,000
Investment, Identifier [Axis]: Boston Trust Walden \| McCormick & Co Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,109,000
Investment, Identifier [Axis]: Boston Trust Walden \| Medpace Holdings Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,502,000
Investment, Identifier [Axis]: Boston Trust Walden \| NetApp Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	880,000
Investment, Identifier [Axis]: Boston Trust Walden \| New York Times Co
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,297,000
Investment, Identifier [Axis]: Boston Trust Walden \| Nordson Corporation
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,547,000
Investment, Identifier [Axis]: Boston Trust Walden \| Northern Trust Corporation
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	855,000
Investment, Identifier [Axis]: Boston Trust Walden \| One Gas Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	732,000
Investment, Identifier [Axis]: Boston Trust Walden \| Paycom Software Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	924,000
Investment, Identifier [Axis]: Boston Trust Walden \| Progress Software Corp
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	718,000
Investment, Identifier [Axis]: Boston Trust Walden \| Qualys Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,542,000
Investment, Identifier [Axis]: Boston Trust Walden \| RPM International Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,154,000
Investment, Identifier [Axis]: Boston Trust Walden \| SEI Investments Company
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,484,000
Investment, Identifier [Axis]: Boston Trust Walden \| Separately Managed Account
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	78,021,000
Investment, Identifier [Axis]: Boston Trust Walden \| Service Corp International
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,270,000
Investment, Identifier [Axis]: Boston Trust Walden \| Silgan Holdings Inc.
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	475,000
Investment, Identifier [Axis]: Boston Trust Walden \| Simply Good Foods Co
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	540,000
Investment, Identifier [Axis]: Boston Trust Walden \| Smith (A.O.) Corp
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,287,000
Investment, Identifier [Axis]: Boston Trust Walden \| Snap On Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,344,000
Investment, Identifier [Axis]: Boston Trust Walden \| Sprouts Farmers Market Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	649,000
Investment, Identifier [Axis]: Boston Trust Walden \| Stag Industrial Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	736,000
Investment, Identifier [Axis]: Boston Trust Walden \| Steris Plc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,459,000
Investment, Identifier [Axis]: Boston Trust Walden \| Teradyne Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,593,000
Investment, Identifier [Axis]: Boston Trust Walden \| Texas Roadhouse Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	841,000
Investment, Identifier [Axis]: Boston Trust Walden \| TopBuild Corp
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,197,000
Investment, Identifier [Axis]: Boston Trust Walden \| Watts Water Technologies
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	1,063,000
Investment, Identifier [Axis]: Boston Trust Walden \| Williams-Sonoma Inc
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	861,000
Investment, Identifier [Axis]: Boston Trust Walden \| Zebra Technologies Corp
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	968,000
Investment, Identifier [Axis]: EARNEST Partners \| Interest in Common Collective Trust
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	78,834,000
Investment, Identifier [Axis]: Eversource Energy \| Cash and Cash Equivalents
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	60,667,000
Investment, Identifier [Axis]: Eversource Energy \| Eversource Common Shares Fund (including the ESOP allocated Eversource Energy Common Shares), $5 par
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	601,416,000
Investment, Identifier [Axis]: Fidelity \| FIAM U.S. Bond Index Commingled Pool Class C
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	26,219,000
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2010 Commingled Pool Class Y
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	12,259,000
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2015 Commingled Pool Class Y
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	341,000
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2020 Commingled Pool Class Y
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	112,170,000
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2025 Commingled Pool Class Y
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	7,334,000
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2030 Commingled Pool Class Y
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	297,627,000
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2035 Commingled Pool Class Y
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	16,642,000
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2040 Commingled Pool Class Y
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	275,394,000
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2045 Commingled Pool Class Y
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	10,805,000
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2050 Commingled Pool Class Y
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	224,053,000
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2055 Commingled Pool Class Y
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	7,362,000
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2060 Commingled Pool Class Y
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	102,854,000
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2065 Commingled Pool Class Y
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	2,758,000
Investment, Identifier [Axis]: Fidelity \| Freedom Blend 2070 Commingled Pool Class Y
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	745,000
Investment, Identifier [Axis]: Fidelity \| Freedom Blend Retirement Commingled Pool Class Y
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	10,861,000
Investment, Identifier [Axis]: Fidelity \| Growth Company Commingled Pool Class F
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	704,902,000
Investment, Identifier [Axis]: Fidelity \| International Discovery Fund – Class K
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	106,564,000
Investment, Identifier [Axis]: Fidelity \| Spartan 500 Index Pool Class E
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	636,122,000
Investment, Identifier [Axis]: Fidelity \| Spartan Extended Market Index Pool Class E
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	21,154,000
Investment, Identifier [Axis]: Fidelity \| Spartan Global ex US Index Pool Class E
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	64,438,000
Investment, Identifier [Axis]: IR+M \| Intermediate Bond Fund - Common Collective Trust
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	96,942,000
Investment, Identifier [Axis]: Prudential \| Investment Contract
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	418,779,000
Investment, Identifier [Axis]: Vanguard \| Windsor II Admiral
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	174,603,000
Investment, Identifier [Axis]: Various \| Brokerage Link
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment, contract value	282,857,000
Separately Managed Account
EBP, Schedule of Asset Held for Investment [Line Items]
Assets held for investment	$ 78,021,000

Fair Value Measurements

12 Months Ended

Dec. 31, 2025

EBP 005

EBP, Investment, Fair Value and NAV [Line Items]

Fair Value Measurements

The Plan discloses fair value measurements pursuant to a framework for measuring fair value in accordance with GAAP. The Plan follows a fair value hierarchy that prioritizes the inputs used to determine fair value and requires the Plan to classify assets and liabilities carried at fair value based on the observability of these inputs. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. The three levels of the fair value hierarchy are:

Level 1 - Inputs are quoted prices (unadjusted) in active markets for identical instruments as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis.

Level 2 - Inputs are quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-derived valuations in which all significant inputs are observable.

Level 3 - Quoted market prices are not available. Fair value is derived from valuation techniques in which one or more significant inputs or assumptions are unobservable. The fair values are therefore determined using model-based valuation techniques that include option pricing models, discounted cash flow models, and similar techniques. As of both December 31, 2025 and 2024, the Plan did not have any assets categorized as Level 3.

Uncategorized - Investments that are measured at net asset value (NAV) as a practical expedient are not categorized within the fair value hierarchy. NAV is determined by dividing the fund's net assets at fair value by its units outstanding at the valuation dates.

The following tables summarize the fair values and levels within the fair value hierarchy:


Fair Value Measurements as of December 31, 2025
(Thousands of Dollars)	Level 1		Level 2		Uncategorized		Total
Investments at Fair Value
Common Collective Trusts	$	—	$	—	$	2,709,815	$	2,709,815
Eversource Common Shares Fund	585,652		—		—		585,652
ESOP Allocated Eversource Energy Common Shares	15,764		—		—		15,764
Registered Investment Companies	281,168		—		—		281,168
Investments Held by Brokerage Link	269,639		13,218		—		282,857
Separately Managed Account	78,021		—		—		78,021

Cash and Cash Equivalents	60,667		—		—		60,667
Total Investments at Fair Value	$	1,290,911	$	13,218	$	2,709,815	$	4,013,944


Fair Value Measurements as of December 31, 2024
(Thousands of Dollars)	Level 1		Level 2		Uncategorized		Total
Investments at Fair Value
Common Collective Trusts	$	—	$	—	$	2,334,587	$	2,334,587
Eversource Common Shares Fund	508,278		—		—		508,278
ESOP Allocated Eversource Energy Common Shares	14,698		—		—		14,698
Registered Investment Companies	286,174		—		—		286,174
Investments Held by Brokerage Link	233,554		12,448		—		246,002
Separately Managed Account	93,636		—		—		93,636
Cash and Cash Equivalents	45,726		—		—		45,726
Total Investments at Fair Value	$	1,182,066	$	12,448	$	2,334,587	$	3,529,101

The fair value of the Eversource Common Shares Fund is based on the closing quoted active market price of the common stock. The fair value of the ESOP allocated Eversource Energy common shares and certain investments in the Brokerage Link assets, including common stock and exchange-traded funds, are

determined by quoted active market prices where available. The fair value of certain investments in registered investment companies and of common stock held in the Separately Managed Account represent the value of such shares as of the close of business at the end of the period based on quoted active market prices of the underlying investments. These investments and cash and cash equivalents have all been categorized as Level 1.

Preferred stock, corporate and government bonds in the Brokerage Link are valued based on quoted prices in non-active markets. Certificates of deposit in the Brokerage Link are valued at the balance reported by the issuing bank. These investments have been categorized as Level 2. In 2024, the Intermediate Bond Fund holdings were replaced by a lower cost common collective trust. For further information, see "Transfers Between Levels," below.

Investments in common collective trusts are recorded at NAV provided by the asset manager, which is based on the market prices of underlying equity and debt securities. These investments are classified as Uncategorized in the table above.

Investment in Contract Held by Insurance Company is stated at contract value in accordance with Accounting Standards Update (ASU) 2015-12, Plan Accounting – Defined Benefit Pension Plans (Topic 960), Defined Contribution Pension Plans (Topic 962), Health and Welfare Benefit Plans (Topic 965), and is therefore not included as an investment measured at fair value in the tables above.

Transfers Between Levels — Changes in the Plan's investment portfolio may require a transfer from one fair value level to another within the fair value hierarchy and the availability of observable market data is monitored to assess the appropriate classification of investments. The Plan’s policy is to recognize transfers between levels at the actual date of the event or change in circumstances that caused the transfer. The significance of transfers are evaluated between levels based upon the nature of the investment and size of the transfer relative to total net assets available for benefits. For the year ended 2025, there were no transfers between levels. In 2024, the Intermediate Bond Fund's investment strategy was restructured to transition from direct holdings in government bonds and corporate debt instruments to participation in a common collective trust, which is fair valued at NAV. As a result, the Intermediate Bond Fund was reclassified from a Level 2 investment to Uncategorized.

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

- Definition

The entire disclosure for fair value of investment held by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), including, but not limited to, fair value measured at net asset value per share as practical expedient (NAV).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-6A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-6A

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-6A

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
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-Paragraph 6A
-Subparagraph (h)
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-6A

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (bbb)(1)
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
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-Name Accounting Standards Codification
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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-URI https://asc.fasb.org/1943274/2147482106/820-10-50-3

Reference 10: http://www.xbrl.org/2003/role/exampleRef
-Topic 962
-SubTopic 325
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
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-URI https://asc.fasb.org/1943274/2147478873/962-325-55-17

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
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-Name Accounting Standards Codification
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-Paragraph 6
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-URI https://asc.fasb.org/1943274/2147477509/962-325-45-6

Reference 13: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 23
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-23

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (g)
-Publisher FASB
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Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
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Reference 16: http://www.xbrl.org/2003/role/disclosureRef
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Reference 17: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

+ Details

Employee Benefit Plan, Statement of Change in Net Asset Available for Benefit (Statement) - EBP 005 - USD ($)	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Additions:
Participant Contributions	$ 149,585,000	$ 141,161,000
Employer Contributions	65,670,000	73,327,000
Rollover Contributions	16,791,000	23,793,000
Total Contributions	232,046,000	238,281,000
Net Appreciation in the Fair Value of Investments	603,211,000	400,039,000
Interest and Dividend Income	78,358,000	98,666,000
Other Income	969,000	3,017,000
Total Additions	914,584,000	740,003,000
Deductions:
Distributions to Participants	472,957,000	443,963,000
Administrative Expenses	1,646,000	1,405,000
Total Deductions	474,603,000	445,368,000
Increase in Net Assets	439,981,000	294,635,000
Net Assets Available for Benefits	$ 4,486,328,000	$ 4,046,347,000	$ 3,751,712,000

Fair Value Measurements (Details) - EBP 005 - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	$ 4,013,944	$ 3,529,101
Common Collective Trusts
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	2,709,815	2,334,587
Eversource Common Shares Fund
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	585,652	508,278
ESOP Allocated Eversource Energy Common Shares
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	15,764	14,698
Registered Investment Companies
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	281,168	286,174
Investments Held by Brokerage Link
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	282,857	246,002
Separately Managed Account
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	78,021	93,636
Cash and Cash Equivalents
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	60,667	45,726
Level 1
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	1,290,911	1,182,066
Level 1 \| Common Collective Trusts
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	0	0
Level 1 \| Eversource Common Shares Fund
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	585,652	508,278
Level 1 \| ESOP Allocated Eversource Energy Common Shares
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	15,764	14,698
Level 1 \| Registered Investment Companies
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	281,168	286,174
Level 1 \| Investments Held by Brokerage Link
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	269,639	233,554
Level 1 \| Separately Managed Account
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	78,021	93,636
Level 1 \| Cash and Cash Equivalents
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	60,667	45,726
Level 2
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	13,218	12,448
Level 2 \| Common Collective Trusts
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	0	0
Level 2 \| Eversource Common Shares Fund
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	0	0
Level 2 \| ESOP Allocated Eversource Energy Common Shares
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	0	0
Level 2 \| Registered Investment Companies
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	0	0
Level 2 \| Investments Held by Brokerage Link
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	13,218	12,448
Level 2 \| Separately Managed Account
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	0	0
Level 2 \| Cash and Cash Equivalents
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	0	0
Uncategorized
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	2,709,815	2,334,587
Uncategorized \| Common Collective Trusts
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	2,709,815	2,334,587
Uncategorized \| Eversource Common Shares Fund
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	0	0
Uncategorized \| ESOP Allocated Eversource Energy Common Shares
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	0	0
Uncategorized \| Registered Investment Companies
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	0	0
Uncategorized \| Investments Held by Brokerage Link
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	0	0
Uncategorized \| Separately Managed Account
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	0	0
Uncategorized \| Cash and Cash Equivalents
EBP, Investment, Fair Value and NAV [Line Items]
Total Investments, at Fair Value	$ 0	$ 0

Cover	12 Months Ended
Cover	Dec. 31, 2025
Document Information [Line Items]
Document Type	11-K
Entity Registrant Name	EVERSOURCE ENERGY
Amendment Flag	false
Entity Central Index Key	0000072741
EBP 005
Document Information [Line Items]
Document Type	11-K
Entity Registrant Name	EVERSOURCE ENERGY
Amendment Flag	false
Entity Central Index Key	0000072741

Administrative Expenses (Details) - USD ($) $ in Millions	12 Months Ended
Administrative Expenses (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
EBP 005
Administrative Expenses [Line Items]
Increase (decrease) in revenue credit allocation	$ 2.0	$ 2.5

Plan Description (Details) - EBP 005	12 Months Ended
Plan Description (Details) - EBP 005	Dec. 31, 2025 USD ($) yr	Dec. 31, 2024 USD ($)
EBP, Description of Plan [Line Items]
Maximum annual compensation to total compensation, percentage	50.00%
Matching percentage	100.00%
Company Contribution	6.00%
Sum of Age and Service Years as of January 1st		6 months
Employer contribution vesting service period	3 years
Forfeited nonvested account	$ 46,518	$ 27,342
Forfeited nonvested account, decrease from employer contribution	$ 1,000,000.0	1,300,000
Participant receipt deferral age \| yr	73
Involuntary cash-out limit	$ 1,000
Note receivable, interest income	3,700,000	3,100,000
Allowance for credit loss	$ 0	$ 0
EBP, Employer Contribution, Tranche One
EBP, Description of Plan [Line Items]
Matching percentage		100.00%
Company Contribution		3.00%
EBP, Employer Contribution, Tranche Two
EBP, Description of Plan [Line Items]
Matching percentage		50.00%
Company Contribution		8.00%
EBP, Employer Contribution, Tranche Three
EBP, Description of Plan [Line Items]
Matching percentage		100.00%
Company Contribution		3.00%

Administrative Expenses	12 Months Ended
Administrative Expenses	Dec. 31, 2025
EBP 005
Administrative Expenses [Line Items]
Administrative Expenses	Administrative Expenses Certain expenses incurred in the administration of the Plan are paid by the Plan, including: Loan initiation fees and various fees associated with the Brokerage Link investment option. Certain fees are paid by the Plan and/or participants. All investment-related expenses of the Plan, any other expenses of the Trustee necessitated by the terms of any particular investment option, and commissions paid with respect to the purchase or sale of common shares for the Plan. These expenses are paid by the Plan and participants, as applicable. The Company, at its discretion, may choose to utilize available forfeiture and/or revenue credits (based on a revenue sharing agreement between Eversource Service and Fidelity) to pay for eligible expenses related to the administration of the Plan, including audit and legal fees. Credits received under this revenue sharing agreement are recognized as Other Income on the Statements of Changes in Net Assets Available for Benefits and may be used to pay certain eligible Plan expenses, or may be allocated to participant accounts at the discretion of the Administrator or the Plan fiduciaries. During 2025 and 2024, $2.0 million and $2.5 million in revenue credits were reallocated back to eligible participant accounts, respectively.

Risks and Uncertainties (Details)	Dec. 31, 2025	Dec. 31, 2024
EBP 005
EBP, Risk and Uncertainty [Line Items]
Concentration of investment at fair value of net assets, percentage	13.00%	13.00%