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REGULATORY ACCOUNTING - Components of Regulatory Liabilities (Details) - USD ($) $ in Thousands | Jun. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | $ 4,911,200 | $ 4,664,900
Less: Current Portion | 834,793 | 632,282
Total Long-Term Regulatory Liabilities | 4,076,390 | 4,032,564
EDIT due to Tax Cuts and Jobs Act of 2017 |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 2,422,100 | 2,442,700
Regulatory Tracking Mechanisms |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 896,800 | 702,400
Cost of Removal |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 717,100 | 684,100
Deferred Portion of Non-Service Income Components of Pension, SERP and PBOP |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 468,600 | 427,100
AFUDC - Transmission |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 166,800 | 154,800
Benefit Costs |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 58,800 | 69,300
Other Regulatory Liabilities |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 181,000 | 184,500
CL&P |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 1,666,200 | 1,520,000
Less: Current Portion | 237,525 | 124,122
Total Long-Term Regulatory Liabilities | 1,428,712 | 1,395,883
CL&P | EDIT due to Tax Cuts and Jobs Act of 2017 |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 952,600 | 956,600
CL&P | Regulatory Tracking Mechanisms |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 289,700 | 180,300
CL&P | Cost of Removal |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 239,600 | 212,800
CL&P | Deferred Portion of Non-Service Income Components of Pension, SERP and PBOP |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 67,200 | 61,600
CL&P | AFUDC - Transmission |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 67,900 | 65,100
CL&P | Benefit Costs |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 5,200 | 4,500
CL&P | Other Regulatory Liabilities |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 44,000 | 39,100
NSTAR Electric |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 2,130,600 | 2,079,400
Less: Current Portion | 480,158 | 436,312
Total Long-Term Regulatory Liabilities | 1,650,390 | 1,643,079
NSTAR Electric | EDIT due to Tax Cuts and Jobs Act of 2017 |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 866,500 | 877,600
NSTAR Electric | Regulatory Tracking Mechanisms |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 457,200 | 413,600
NSTAR Electric | Cost of Removal |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 448,900 | 451,300
NSTAR Electric | Deferred Portion of Non-Service Income Components of Pension, SERP and PBOP |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 232,500 | 211,600
NSTAR Electric | AFUDC - Transmission |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 98,900 | 89,700
NSTAR Electric | Benefit Costs |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 12,700 | 21,400
NSTAR Electric | Other Regulatory Liabilities |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 13,900 | 14,200
PSNH |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 506,500 | 516,100
Less: Current Portion | 103,868 | 121,058
Total Long-Term Regulatory Liabilities | 402,644 | 394,982
PSNH | EDIT due to Tax Cuts and Jobs Act of 2017 |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 326,600 | 330,600
PSNH | Regulatory Tracking Mechanisms |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 93,500 | 114,400
PSNH | Cost of Removal |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 28,600 | 20,100
PSNH | Deferred Portion of Non-Service Income Components of Pension, SERP and PBOP |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 45,600 | 42,600
PSNH | AFUDC - Transmission |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 0 | 0
PSNH | Benefit Costs |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | 4,200 | 3,900
PSNH | Other Regulatory Liabilities |  |
Regulatory Liabilities [Line Items] |  |
Total Regulatory Liabilities | $ 8,000 | $ 4,500

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- Definition The amount for the individual regulatory liability as itemized in a table of regulatory liabilities as of the end of the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 980 -SubTopic 405 -Name Accounting Standards Codification -Section 25 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477571/980-405-25-1 + Details
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