SHORT-TERM AND LONG-TERM DEBT - Summary of Long-Term Debt Issuance and Repayments (Details) - USD ($) $ in Millions	1 Months Ended
Apr. 30, 2024	Jan. 31, 2024
Senior Notes \| Eversource Parent Series DD Senior Notes \| Eversource Parent
Debt Instrument [Line Items]
Interest rate, stated percentage (in percent)		5.00%
Issuances		$ 350.0
Senior Notes \| Eversource Parent Series EE Senior Notes \| Eversource Parent
Debt Instrument [Line Items]
Interest rate, stated percentage (in percent)		5.50%
Issuances		$ 650.0
Senior Notes \| Eversource Parent Series FF Senior Notes \| Subsequent Event \| Eversource Parent
Debt Instrument [Line Items]
Interest rate, stated percentage (in percent)	5.85%
Issuances	$ 700.0
Senior Notes \| Eversource Parent Series GG Senior Notes \| Subsequent Event \| Eversource Parent
Debt Instrument [Line Items]
Interest rate, stated percentage (in percent)	5.95%
Issuances	$ 700.0
CL&P \| First Mortgage \| CL&P 2024 Series A First Mortgage Bonds
Debt Instrument [Line Items]
Interest rate, stated percentage (in percent)		4.65%
Issuances		$ 350.0
PSNH \| First Mortgage \| PSNH Series X First Mortgage Bonds \| Subsequent Event
Debt Instrument [Line Items]
Interest rate, stated percentage (in percent)	5.35%
Issuances	$ 300.0

Contractual interest rate for funds borrowed, under the debt agreement.

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