SHORT-TERM AND LONG-TERM DEBT - Summary of Long-Term Debt Issuance and Repayments (Details) - USD ($) $ in Millions		1 Months Ended
	Feb. 28, 2026	Mar. 31, 2026	Feb. 28, 2026
Eversource Parent Series A Junior Notes
Debt Instrument [Line Items]
Interest Rate (in percent)	6.10%		6.10%
Issuance			$ 750.0
Debt instrument term (in years)	5 years
Spread rate (in percent)	2.521%
Eversource Parent Series B Junior Notes
Debt Instrument [Line Items]
Interest Rate (in percent)	6.35%		6.35%
Issuance			$ 750.0
Debt instrument term (in years)	5 years
Spread rate (in percent)	2.325%
Eversource Parent Series J Senior Notes
Debt Instrument [Line Items]
Interest Rate (in percent)		3.35%
Repayments		$ (250.0)