XML 199 R171.htm IDEA: XBRL DOCUMENT v3.25.0.1
REVENUES - Narrative (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Loss Contingencies [Line Items]        
Revenue $ 11,801,800 $ 11,890,600 $ 12,270,200  
Loss related to litigation settlement 0 0 (72,041)  
Lease revenue $ 2,500 $ 4,600 $ 4,000  
Operating Lease, Lease Income, Statement of Income or Comprehensive Income [Extensible Enumeration] Other Income, Net Other Income, Net Other Income, Net  
CL&P        
Loss Contingencies [Line Items]        
Loss related to litigation settlement $ 0 $ 0 $ (72,041)  
Lease revenue 500 700 800  
NSTAR Electric        
Loss Contingencies [Line Items]        
Lease revenue 1,200 2,500 2,500  
Reserve for Revenues Subject to Refund        
Loss Contingencies [Line Items]        
Revenue (1,900) 4,300 72,000  
Operating Segments | CL&P        
Loss Contingencies [Line Items]        
Revenue 5,222,100 5,077,600 5,343,200  
Operating Segments | NSTAR Electric        
Loss Contingencies [Line Items]        
Revenue 4,332,000 4,129,400 4,127,300  
Operating Segments | Reserve for Revenues Subject to Refund | CL&P        
Loss Contingencies [Line Items]        
Revenue 0 4,300 72,700  
Operating Segments | Reserve for Revenues Subject to Refund | NSTAR Electric        
Loss Contingencies [Line Items]        
Revenue $ 0 $ 0 $ 0  
Unfavorable Regulatory Action | Operating Segments | Reserve for Revenues Subject to Refund | CL&P        
Loss Contingencies [Line Items]        
Revenue       $ 93,400