RATE REDUCTION BONDS AND VARIABLE INTEREST ENTITIES - Summary of the Impact of Funding on the Income Statements (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Condensed Income Statements, Captions [Line Items]
Interest Expense on RRB Principal (included in Interest Expense)	$ 271,300	$ 207,300	$ 522,100	$ 401,900
PSNH
Condensed Income Statements, Captions [Line Items]
Amortization of RRB Principal (included in Amortization of Regulatory Assets/(Liabilities), Net)	(28,729)	19,954	(49,993)	25,271
PSNH | VIE | Rate Reduction Bonds
Condensed Income Statements, Captions [Line Items]
Amortization of RRB Principal (included in Amortization of Regulatory Assets/(Liabilities), Net)	10,800	10,800	21,600	21,600
Interest Expense on RRB Principal (included in Interest Expense)	$ 3,600	$ 3,900	$ 7,300	$ 8,000