INCOME TAXES - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating Loss Carryforwards [Line Items]
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	82.8	61.5
State and Local Jurisdiction | CL&P
Operating Loss Carryforwards [Line Items]
Change in valuation allowance	18.8	10.8
Eversource | State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Change in valuation allowance	$ 21.3	$ 13.0