RATE REDUCTION BONDS AND VARIABLE INTEREST ENTITIES - Impact of Funding on the Income Statements (Details) - PSNH - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Condensed Income Statements, Captions [Line Items]
Amortization of Regulatory Assets, Net	$ 26,650	$ 20,835
VIE | Rate Reduction Bonds
Condensed Income Statements, Captions [Line Items]
Amortization of Regulatory Assets, Net	10,800	10,800
Interest Expense on RRB Principal (included in Interest Expense)	$ 2,900	$ 3,300