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COMMITMENTS AND CONTINGENCIES - Schedule of Number of Sites and Reserves (Details) - site	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Loss Contingencies [Line Items]
Number of Sites	65	65
CL&P
Loss Contingencies [Line Items]
Number of Sites	15	16
NSTAR Electric
Loss Contingencies [Line Items]
Number of Sites	14	12
PSNH
Loss Contingencies [Line Items]
Number of Sites	8	8

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