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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

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- Definition Number of environmental sites by NU Entity in the remediation or long-term monitoring phase + References No definition available. + 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. + Details
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- Details
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- Details
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- Details
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