COMMITMENTS AND CONTINGENCIES - Environmental Sites and Related Reserves (Details) $ in Millions |
6 Months Ended | 12 Months Ended |
|---|---|---|
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Jun. 30, 2025
USD ($)
site
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Dec. 31, 2024
USD ($)
site
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| Site Contingency [Line Items] | ||
| Number of Sites | site | 65 | 65 |
| Reserve | $ | $ 152.2 | $ 128.0 |
| CL&P | ||
| Site Contingency [Line Items] | ||
| Number of Sites | site | 15 | 15 |
| Reserve | $ | $ 13.8 | $ 13.4 |
| NSTAR Electric | ||
| Site Contingency [Line Items] | ||
| Number of Sites | site | 14 | 14 |
| Reserve | $ | $ 8.3 | $ 6.6 |
| PSNH | ||
| Site Contingency [Line Items] | ||
| Number of Sites | site | 8 | 8 |
| Reserve | $ | $ 9.1 | $ 6.3 |
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- Definition Number of environmental sites by NU Entity in the remediation or long-term monitoring phase No definition available.
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- Definition Total costs accrued as of the balance sheet date for environmental loss contingencies. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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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. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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