COMMITMENTS AND CONTINGENCIES - Schedule of Number of Sites and Reserves (Details) - site	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Loss Contingencies [Line Items]
Number of Sites	59	61
CL&P
Loss Contingencies [Line Items]
Number of Sites	13	14
NSTAR Electric
Loss Contingencies [Line Items]
Number of Sites	10	11
PSNH
Loss Contingencies [Line Items]
Number of Sites	8	9