v3.25.2
COMMITMENTS AND CONTINGENCIES - Schedule of Guarantees and Indemnifications (Details)
$ in Millions
6 Months Ended
Jun. 30, 2025
USD ($)
letterOfCredit
Sep. 30, 2024
USD ($)
Guarantor Obligations [Line Items]    
Maximum Exposure   $ 850.0
Number of letters of credit | letterOfCredit 2  
Eversource Investment LLC | Letters of Credit    
Guarantor Obligations [Line Items]    
Maximum Exposure $ 4.3  
Maximum borrowing capacity $ 25.0  
North East Offshore, Revolution Wind, LLC and South Fork Wind, LLC    
Guarantor Obligations [Line Items]    
Ownership interest (percent) 50.00%  
South Fork Class B Member, LLC    
Guarantor Obligations [Line Items]    
Ownership interest (percent) 50.00%  
Eversource Investment LLC, Eversource Investment Service Company LLC and South Fork Class B Member, LLC    
Guarantor Obligations [Line Items]    
Maximum Exposure $ 1,620.0  
South Fork Wind, LLC    
Guarantor Obligations [Line Items]    
Maximum Exposure $ 7.1  
Ownership interest (percent) 50.00%  
Performance Guarantee | Eversource Investment Service Company LLC    
Guarantor Obligations [Line Items]    
Maximum Exposure $ 100.0  
Tax Equity | Eversource TEI LLC    
Guarantor Obligations [Line Items]    
Maximum Exposure 50.0  
Revolution Wind, LLC and TurbineCo, LLC | Construction-related purchase agreements with third-party contractors    
Guarantor Obligations [Line Items]    
Maximum Exposure 183.6  
Eversource Investment LLC, Eversource Investment Service Company LLC and South Fork Class B Member, LLC | Funding and indemnification obligations of North East Offshore LLC    
Guarantor Obligations [Line Items]    
Maximum Exposure 202.6  
Eversource Investment LLC | Letters Of Credit Guarantee    
Guarantor Obligations [Line Items]    
Maximum Exposure 4.3  
Eversource TEI LLC | South Fork Wind Tax Equity    
Guarantor Obligations [Line Items]    
Maximum Exposure 50.0  
South Fork Wind, LLC | Power Purchase Guarantee    
Guarantor Obligations [Line Items]    
Maximum Exposure 7.1  
Various Eversource subsidiaries | Surety Bond    
Guarantor Obligations [Line Items]    
Maximum Exposure 34.1  
North East Offshore, Revolution Wind, LLC, TurbineCo, LLC | Performance Guarantee    
Guarantor Obligations [Line Items]    
Maximum Exposure $ 745.2