v3.26.1
PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Public Utility, Property, Plant and Equipment [Line Items]    
Distribution - Electric $ 23,536,100 $ 22,695,300
Distribution - Natural Gas 9,980,200 9,888,000
Transmission - Electric 17,283,300 17,082,400
Distribution - Water 0 2,577,300
Solar 206,800 206,800
Utility 51,006,400 52,449,800
Other 2,655,400 2,476,300
Property, Plant and Equipment, Gross 53,661,800 54,926,100
Less:  Accumulated Depreciation    
Utility (10,502,900) (10,911,700)
Other (1,386,700) (1,246,100)
Total Accumulated Depreciation (11,889,600) (12,157,800)
Property, Plant and Equipment, Net 41,772,200 42,768,300
Construction Work in Progress 3,498,400 3,162,700
Total Property, Plant and Equipment, Net 45,270,581 45,930,959
CL&P    
Public Utility, Property, Plant and Equipment [Line Items]    
Distribution - Electric 9,127,400 8,906,000
Transmission - Electric 7,288,200 7,222,500
Solar 0 0
Property, Plant and Equipment, Gross 16,415,600 16,128,500
Less:  Accumulated Depreciation    
Total Accumulated Depreciation (3,181,400) (3,081,300)
Property, Plant and Equipment, Net 13,234,200 13,047,200
Construction Work in Progress 720,500 576,100
Total Property, Plant and Equipment, Net 13,954,692 13,623,296
NSTAR Electric    
Public Utility, Property, Plant and Equipment [Line Items]    
Distribution - Electric 11,172,300 10,635,700
Transmission - Electric 6,792,100 6,722,900
Solar 206,800 206,800
Property, Plant and Equipment, Gross 18,171,200 17,565,400
Less:  Accumulated Depreciation    
Total Accumulated Depreciation (4,150,500) (4,014,200)
Property, Plant and Equipment, Net 14,020,700 13,551,200
Construction Work in Progress 1,891,300 1,757,700
Total Property, Plant and Equipment, Net 15,911,988 15,308,896
PSNH    
Public Utility, Property, Plant and Equipment [Line Items]    
Distribution - Electric 3,276,700 3,193,800
Transmission - Electric 3,204,800 3,138,700
Solar 0 0
Property, Plant and Equipment, Gross 6,481,500 6,332,500
Less:  Accumulated Depreciation    
Total Accumulated Depreciation (1,118,300) (1,085,400)
Property, Plant and Equipment, Net 5,363,200 5,247,100
Construction Work in Progress 269,300 260,600
Total Property, Plant and Equipment, Net $ 5,632,513 $ 5,507,663