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- Definition

Loss Contingency, Percentage of Base ROE Challenged by Complainants

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- Definition

Loss Contingency, Estimated Of Interest Component

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- Definition

Loss Contingency, Maximum Percentage Of ROE For Incentive Projects

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- Definition

Loss Contingency, Percentage Of Base ROE Reasonably Justified

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- Definition

Loss Contingency, Percentage Of Incentive Cap On Total ROE

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- Definition

Loss Contingency, Percentage Of ROE For Any Incentive Project

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- Definition

Loss Contingency, Percentage of ROE for Any Incentive Project

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- Definition

Loss Contingency, Period Of Complaint

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- Definition

Percentage Of Base ROE Of Complaint Period

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No definition available.

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- Definition

Percentage of Base ROE of Complaint Period

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No definition available.

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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.

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- Definition

Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

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- Definition

Number of pending claims pertaining to a loss contingency.

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- Definition

The amount for the individual regulatory liability as itemized in a table of regulatory liabilities as of the end of the period.

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COMMITMENTS AND CONTINGENCIES - FERC ROE Complaints Narrative (Details) $ in Millions						6 Months Ended	15 Months Ended	30 Months Ended	36 Months Ended
	Apr. 30, 2026	Apr. 20, 2026	Mar. 19, 2026 complaint	Oct. 16, 2018 complaint	Apr. 29, 2016 complaint	Jun. 30, 2026 USD ($)	Dec. 31, 2012	Apr. 14, 2017	Oct. 15, 2014	Dec. 31, 2025 USD ($)	Jul. 31, 2014 complaint
Loss Contingencies [Line Items]
Percentage of base ROE reasonably justified (in percent)				10.41%
Percentage of incentive cap on total ROE				13.08%
Regulatory liabilities						$ 5,927.5				$ 5,538.1
CL&P
Loss Contingencies [Line Items]
Regulatory liabilities						2,133.4				1,862.6
NSTAR Electric
Loss Contingencies [Line Items]
Regulatory liabilities						2,503.6				2,352.9
PSNH
Loss Contingencies [Line Items]
Regulatory liabilities						$ 583.1				$ 535.8
Proposed ROE
Loss Contingencies [Line Items]
Percentage of base ROE of complaint period	11.39%
Proposed Cap
Loss Contingencies [Line Items]
Maximum percentage cap of ROE for incentive projects	12.89%
FERC ROE Complaints
Loss Contingencies [Line Items]
Loss contingency, pending claims, number \| complaint			4	4	4
Period of complaint						15 months
Loss contingency, estimate of possible earnings impact						$ 906.4
FERC ROE Complaints \| CL&P
Loss Contingencies [Line Items]
Regulatory liabilities						29.8
FERC ROE Complaints \| NSTAR Electric
Loss Contingencies [Line Items]
Regulatory liabilities						24.6
FERC ROE Complaints \| PSNH
Loss Contingencies [Line Items]
Regulatory liabilities						7.6
FERC ROE Complaints \| Minimum
Loss Contingencies [Line Items]
Loss contingency, estimate of possible earnings impact						62.0
Estimated of Interest						30.1
FERC ROE Complaints \| Maximum
Loss Contingencies [Line Items]
Loss contingency, estimate of possible earnings impact						968.4
Estimated of Interest						$ 271.5
FERC ROE First, Second and Third Complaints
Loss Contingencies [Line Items]
Loss contingency, pending claims, number \| complaint											3
Base ROE percentage challenged by complainants						11.14%
FERC ROE First, Second and Third Complaints \| Minimum
Loss Contingencies [Line Items]
Maximum percentage cap of ROE for incentive projects									11.14%
FERC ROE First, Second and Third Complaints \| Maximum
Loss Contingencies [Line Items]
Maximum percentage cap of ROE for incentive projects									13.10%
FERC ROE Fourth Complaint
Loss Contingencies [Line Items]
Percentage of base ROE of complaint period					10.57%
Maximum percentage cap of ROE for incentive projects					11.74%
FERC ROE Second Complaint
Loss Contingencies [Line Items]
Percentage of base ROE								10.57%
FERC ROE First Complaint
Loss Contingencies [Line Items]
Percentage of ROE for any incentive								11.74%
Regulatory liabilities						$ 62.0
FERC ROE First Complaint \| CL&P
Loss Contingencies [Line Items]
Interest component of regulatory liability						14.4
FERC ROE First Complaint \| NSTAR Electric
Loss Contingencies [Line Items]
Interest component of regulatory liability						12.0
FERC ROE First Complaint \| PSNH
Loss Contingencies [Line Items]
Interest component of regulatory liability						$ 3.7
FERC ROE First Complaint \| Original ROE
Loss Contingencies [Line Items]
Percentage of base ROE of complaint period			11.14%				11.14%
Percentage of base ROE		11.14%							11.14%
FERC ROE First Complaint \| Revised ROE
Loss Contingencies [Line Items]
Percentage of base ROE of complaint period							9.57%
Percentage of base ROE									10.57%
FERC ROE First Complaint \| Incentive Cap
Loss Contingencies [Line Items]
Maximum percentage cap of ROE for incentive projects						12.09%	12.09%
FERC ROE First Complaint \| Previous Order ROE
Loss Contingencies [Line Items]
Percentage of base ROE of complaint period						10.57%
FERC ROE First Complaint \| Previous Incentive Cap
Loss Contingencies [Line Items]
Maximum percentage cap of ROE for incentive projects						11.74%
FERC ROE First Complaint \| Final ROE
Loss Contingencies [Line Items]
Percentage of base ROE of complaint period		9.57%				9.57%