Estimate of possible loss for each 10 basis point change to base ROE

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- Definition

Loss Contingency, Percentage of Base ROE Challenged by Complainants

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No definition available.

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- Definition

Loss Contingency, Basis Spread

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- Definition

Loss Contingency, Maximum percentage of ROE for incentive projects

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- Definition

Loss Contingency, Original Base ROE Authorized by FERC at Time of Complaint

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No definition available.

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- Definition

Loss Contingency, Percentage Of Base ROE Reasonably Justified

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No definition available.

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- Definition

Loss Contingency, Percentage Of Incentive Cap On Total ROE

+ References

No definition available.

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- Definition

Loss Contingency, Percentage of ROE for Any Incentive Project

+ References

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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

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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No definition available.

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- Definition

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

+ References

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- Definition

Number of pending claims pertaining to a loss contingency.

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- Definition

Cash receipts from customers during the current period which are usually for sales of goods and services.

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COMMITMENTS AND CONTINGENCIES - FERC ROE Complaints (Details) $ in Millions				12 Months Ended	30 Months Ended	36 Months Ended
	Oct. 16, 2018 complaint	Oct. 06, 2017	Apr. 29, 2016 complaint	Dec. 31, 2020 USD ($)	Apr. 14, 2017	Oct. 15, 2014	Jul. 31, 2014 complaint
Loss Contingencies [Line Items]
Percentage of base ROE reasonably justified	10.41%
Percentage of incentive cap on total ROE	13.08%
FERC ROE Complaints
Loss Contingencies [Line Items]
Loss contingency, pending claims, number \| complaint	4		4
Period of complaint				15 months
Basis point change				0.10%
Estimate of possible loss for each 10 basis point change to base ROE				$ 3.0
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%
Percentage of ROE for any incentive project	13.08%
FERC ROE First Complaint
Loss Contingencies [Line Items]
Percentage of ROE for any incentive project					11.74%
Refund payments				$ 38.9
FERC ROE Second Complaint
Loss Contingencies [Line Items]
Percentage of base ROE of complaint period				10.57%	10.57%
Percentage of ROE for any incentive project				11.74%
Loss contingency, estimate of possible earnings impact				$ 39.1
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%
Percentage of ROE for any incentive project		10.57%
Original base ROE authorized by FERC at time of complaint		11.74%
The Connecticut Light and Power Company \| FERC ROE First Complaint
Loss Contingencies [Line Items]
Refund payments				22.4
The Connecticut Light and Power Company \| FERC ROE Second Complaint
Loss Contingencies [Line Items]
Loss contingency, estimate of possible earnings impact				21.4
NSTAR Electric Company \| FERC ROE First Complaint
Loss Contingencies [Line Items]
Refund payments				13.7
NSTAR Electric Company \| FERC ROE Second Complaint
Loss Contingencies [Line Items]
Loss contingency, estimate of possible earnings impact				14.6
Public Service Company of New Hampshire \| FERC ROE First Complaint
Loss Contingencies [Line Items]
Refund payments				2.8
Public Service Company of New Hampshire \| FERC ROE Second Complaint
Loss Contingencies [Line Items]
Loss contingency, estimate of possible earnings impact				$ 3.1
Minimum \| FERC ROE First, Second and Third Complaints
Loss Contingencies [Line Items]
Percentage of ROE for any incentive project						11.14%
Maximum \| FERC ROE First, Second and Third Complaints
Loss Contingencies [Line Items]
Percentage of ROE for any incentive project						13.10%