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COMMITMENTS AND CONTINGENCIES - CL&P Comprehensive Settlement Agreement (Details) - USD ($) $ / shares in Units, $ in Thousands |  | 12 Months Ended |
--- | --- | --- | ---
Oct. 01, 2021 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | Jul. 14, 2021
Loss Contingencies [Line Items] |  |  |  |  |
Regulatory Liabilities |  | $ 602,432 | $ 389,430 |  |
Loss related to litigation settlement |  | 81,274 | 0 | $ 0 |
Basis points reduction to return on equity, scenario one | 0.90% |  |  |  |
Basis points reduction to return on equity, scenario two | 0.45% |  |  |  |
The Connecticut Light and Power Company |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |
Regulatory Liabilities |  | 266,489 | 137,166 |  |
Loss related to litigation settlement |  | 81,274 | $ 0 | $ 0 |
Unfavorable Regulatory Action |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |
Loss related to litigation settlement |  | 103,600 |  |  |
Customer credits and assistance | $ 75,000 |  |  |  |
Loss related to litigation settlement, net of tax |  | $ 86,100 |  |  |
Loss contingency, after-tax earnings impact per share (in dollars per share) |  | $ 0.25 |  |  | $ (0.07)
Unfavorable Regulatory Action | Sales |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |
Loss related to litigation settlement |  | $ 65,000 |  |  |
Unfavorable Regulatory Action | Oil and Gas, Operation and Maintenance |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |
Loss related to litigation settlement |  | 10,000 |  |  |
Unfavorable Regulatory Action | The Connecticut Light and Power Company |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |
Customer credits | 65,000 |  |  |  |
Customer assistance initiatives | $ 10,000 |  |  |  |
Regulatory Liabilities |  | 75,000 |  |  |
Unfavorable Regulatory Action | The Connecticut Light and Power Company | Sales |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |
Loss related to litigation settlement |  | $ 65,000 |  |  |

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- Definition Gain ​(Loss) Related To Litigation Settlement, Net Of Tax + References No definition available. + Details
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- Definition Amount of gain (loss) recognized in settlement of litigation and insurance claims. Excludes claims within an insurance entity's normal claims settlement process. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349 + Details
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