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INCOME TAXES - Narrative (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020
Operating Loss Carryforwards [Line Items] |  |
Tax liability related to the deferral of employer payroll tax liability provision of the CARES Act | $ 19.6 | $ 39.0
Accrued interest payable | 0.1 | 0.1
State and Local Jurisdiction |  |
Operating Loss Carryforwards [Line Items] |  |
Valuation allowance for tax credit and operating loss carryforward | 61.5 | 48.3
State and Local Jurisdiction | The Connecticut Light and Power Company |  |
Operating Loss Carryforwards [Line Items] |  |
Change in valuation allowance | 10.8 | 8.8
Eversource | State and Local Jurisdiction |  |
Operating Loss Carryforwards [Line Items] |  |
Change in valuation allowance | $ 13.0 | $ 10.3

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- Definition Amount of valuation allowance pertaining to the deferred tax asset representing potential future taxable deductions from tax credit carryforwards and operating loss carryforwards for which it is more likely than not that a tax benefit will not be realized. + References No definition available. + Details
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- Definition The amount of estimated penalties and interest accrued as of the balance sheet date arising from income tax examinations. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32718-109319 + Details
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