v3.26.1
RATE REDUCTION BONDS AND VARIABLE INTEREST ENTITIES - Impact of Funding on the Balance Sheets (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Condensed Balance Sheet Statements, Captions [Line Items]    
Securitized Stranded Cost (included in Regulatory Assets) $ 7,146,200 $ 7,693,700
Other Regulatory Liabilities (included in Regulatory Liabilities) 4,231,128 4,273,465
Accrued Interest (included in Other Current Liabilities) 1,001,529 894,219
Rate Reduction Bonds - Current Portion 43,210 43,210
Rate Reduction Bonds - Long-Term Portion 259,257 280,862
Securitized Stranded Costs    
Condensed Balance Sheet Statements, Captions [Line Items]    
Securitized Stranded Cost (included in Regulatory Assets) 284,500 306,100
Other Regulatory Assets    
Condensed Balance Sheet Statements, Captions [Line Items]    
Securitized Stranded Cost (included in Regulatory Assets) 142,700 189,900
Balance Sheet Location [Axis]: us-gaap:MarketableSecurities    
Condensed Balance Sheet Statements, Captions [Line Items]    
Restricted Cash 11,900 14,000
Balance Sheet Location [Axis]: us-gaap:OtherAssetsNoncurrent    
Condensed Balance Sheet Statements, Captions [Line Items]    
Restricted Cash 3,200 3,200
Balance Sheet Location [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Condensed Balance Sheet Statements, Captions [Line Items]    
Restricted Cash 59,700 93,600
PSNH    
Condensed Balance Sheet Statements, Captions [Line Items]    
Securitized Stranded Cost (included in Regulatory Assets) 963,600 961,100
Other Regulatory Liabilities (included in Regulatory Liabilities) 432,400 417,442
Accrued Interest (included in Other Current Liabilities) 32,627 41,604
Rate Reduction Bonds - Current Portion 43,210 43,210
Rate Reduction Bonds - Long-Term Portion 259,257 280,862
PSNH | VIE    
Condensed Balance Sheet Statements, Captions [Line Items]    
Rate Reduction Bonds - Current Portion 43,200 43,200
Rate Reduction Bonds - Long-Term Portion 259,300 280,900
PSNH | Securitized Stranded Costs    
Condensed Balance Sheet Statements, Captions [Line Items]    
Securitized Stranded Cost (included in Regulatory Assets) 284,500 306,100
PSNH | Securitized Stranded Costs | VIE    
Condensed Balance Sheet Statements, Captions [Line Items]    
Securitized Stranded Cost (included in Regulatory Assets) 284,500 306,100
PSNH | Other Regulatory Assets    
Condensed Balance Sheet Statements, Captions [Line Items]    
Securitized Stranded Cost (included in Regulatory Assets) 2,500 3,000
PSNH | Other Regulatory Assets | VIE    
Condensed Balance Sheet Statements, Captions [Line Items]    
Other Regulatory Liabilities (included in Regulatory Liabilities) 7,500 7,300
Accrued Interest (included in Other Current Liabilities) 4,800 5,100
PSNH | Balance Sheet Location [Axis]: us-gaap:MarketableSecurities    
Condensed Balance Sheet Statements, Captions [Line Items]    
Restricted Cash 0 0
PSNH | Balance Sheet Location [Axis]: us-gaap:OtherAssetsNoncurrent    
Condensed Balance Sheet Statements, Captions [Line Items]    
Restricted Cash 3,200 3,200
PSNH | Balance Sheet Location [Axis]: us-gaap:OtherAssetsNoncurrent | VIE    
Condensed Balance Sheet Statements, Captions [Line Items]    
Restricted Cash 3,200 3,200
PSNH | Balance Sheet Location [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Condensed Balance Sheet Statements, Captions [Line Items]    
Restricted Cash 34,400 38,300
PSNH | Balance Sheet Location [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent | VIE    
Condensed Balance Sheet Statements, Captions [Line Items]    
Restricted Cash $ 30,600 $ 30,600