Capacity Available Under Preferred Stock Provisions

No definition available.

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- Definition

Line of Credit Facility, Amount Outstanding During Period

+ References

No definition available.

+ Details

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- Definition

Percentage of Total Capitalization

+ References

No definition available.

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- Definition

Period of Maturity Restricting Provisions of Debt

+ References

No definition available.

+ Details

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- Definition

Short-Term Borrowing Limit Approved By Regulatory Agency

+ References

No definition available.

+ Details

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- References

No definition available.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(a)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
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-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

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- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
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-Name Accounting Standards Codification
-Section S99
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-Subparagraph (SX 210.7-03(a)(16)(a)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(b))
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-Topic 210
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-Paragraph 1
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

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- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt classified as noncurrent. Excludes lease obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

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- Definition

Sum of the carrying values as of the balance sheet date of the portions of long-term notes payable due within one year or the operating cycle if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(20))
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-Paragraph 1
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

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- 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

No definition available.

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SHORT-TERM DEBT - Narrative (Details) - USD ($)	12 Months Ended
SHORT-TERM DEBT - Narrative (Details) - USD ($)	Dec. 31, 2024	Dec. 31, 2023	Dec. 18, 2023	Nov. 30, 2023
Short-term Debt [Line Items]
Long-term debt	$ 25,701,627,000	$ 23,588,616,000
Eversource
Short-term Debt [Line Items]
Long-term debt	10,729,256,000	9,952,351,000
Commercial Paper
Short-term Debt [Line Items]
Long-term debt		990,900,000
Commercial Paper \| Eversource
Short-term Debt [Line Items]
Maximum borrowing capacity	2,000,000,000.00
Line of Credit
Short-term Debt [Line Items]
Amount outstanding during period	0	0
Line of Credit \| Eversource
Short-term Debt [Line Items]
Maximum borrowing capacity	$ 2,000,000,000.00
Debt instrument term (in years)	5 years
CL&P
Short-term Debt [Line Items]
Short-term borrowing limit approved by regulatory agency				$ 600,000,000
Long-term debt	$ 5,108,173,000	4,814,429,000
Notes payable	280,000,000	249,670,000
CL&P \| Related Party
Short-term Debt [Line Items]
Long-term debt		207,300,000
Notes payable	$ 280,000,000.0	457,000,000
CL&P \| Unsecured Debt
Short-term Debt [Line Items]
Period of maturity restricting provisions of debt	10 years
Total capitalization (as a percentage)	10.00%
Capacity available under preferred stock provisions	$ 901,000,000.0
CL&P \| Commercial Paper
Short-term Debt [Line Items]
Long-term debt		139,800,000
CL&P \| Commercial Paper
Short-term Debt [Line Items]
Long-term debt		207,300,000
CL&P \| Line of Credit
Short-term Debt [Line Items]
Maximum borrowing capacity	375,000,000
Borrowings outstanding	0
NSTAR Electric
Short-term Debt [Line Items]
Short-term borrowing limit approved by regulatory agency			$ 655,000,000
Long-term debt	4,844,920,000	4,496,947,000
Notes payable	504,782,000	365,847,000
NSTAR Electric \| Unsecured Debt
Short-term Debt [Line Items]
Long-term debt	5,000,000,000	4,400,000,000
NSTAR Electric \| Commercial Paper
Short-term Debt [Line Items]
Maximum borrowing capacity	650,000,000
NSTAR Electric \| Line of Credit
Short-term Debt [Line Items]
Maximum borrowing capacity	$ 650,000,000
Debt instrument term (in years)	5 years
PSNH
Short-term Debt [Line Items]
Short-term borrowing limit approved by regulatory agency	$ 526,700,000
Long-term debt	1,732,066,000	1,431,591,000
Notes payable	131,100,000	233,000,000
PSNH \| Related Party
Short-term Debt [Line Items]
Notes payable	$ 131,100,000	$ 233,000,000.0
PSNH \| Short Term Debt Authorization Calculation
Short-term Debt [Line Items]
Interest rate	10.00%
Short-term debt borrowing calculation approved by regulatory agency	$ 60,000,000
PSNH \| Line of Credit
Short-term Debt [Line Items]
Maximum borrowing capacity	250,000,000
Borrowings outstanding	$ 0