v3.25.2
REVENUES (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers $ 2,827,800 $ 2,515,300 $ 6,934,300 $ 5,792,100
Alternative Revenue Programs 6,400 13,500 10,900 62,600
Other Revenues 3,900 4,700 11,200 11,400
Total Operating Revenues 2,838,068 2,533,522 6,956,423 5,866,097
CL&P        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues 1,132,168 964,623 2,673,357 2,085,914
NSTAR Electric        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues 868,925 845,068 1,883,152 1,792,683
PSNH        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues 303,133 287,311 651,114 613,427
Total Retail Tariff Sales Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 2,436,800 2,206,300 5,947,900 5,110,700
Residential        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 1,379,000 1,269,400 3,596,200 3,061,300
Commercial        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 913,000 816,300 2,039,900 1,785,300
Industrial        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 144,800 120,600 311,800 264,100
Wholesale Transmission Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 156,800 116,800 311,500 229,300
Wholesale Market Sales Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 205,200 168,000 616,300 392,500
Other Revenues from Contracts with Customers        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 29,000 24,200 58,600 59,600
Operating Segments | CL&P        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 1,307,400 1,112,000 3,040,900 2,362,900
Alternative Revenue Programs 3,200 23,900 (15,700) 51,300
Other Revenues 100 1,500 2,800 4,300
Operating Segments | NSTAR Electric        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 1,061,400 1,006,000 2,262,100 2,103,100
Alternative Revenue Programs (7,900) 4,200 (17,000) 12,000
Other Revenues 2,200 1,600 4,600 3,600
Operating Segments | PSNH        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 388,100 348,100 822,200 722,000
Alternative Revenue Programs (18,800) 3,400 (38,500) 11,000
Other Revenues 600 600 1,500 1,400
Operating Segments | Total Retail Tariff Sales Revenues | CL&P        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 937,000 794,300 2,130,800 1,706,800
Operating Segments | Total Retail Tariff Sales Revenues | NSTAR Electric        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 790,600 764,800 1,703,300 1,630,400
Operating Segments | Total Retail Tariff Sales Revenues | PSNH        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 251,700 241,800 546,800 513,400
Operating Segments | Residential | CL&P        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 583,500 513,700 1,384,800 1,140,600
Operating Segments | Residential | NSTAR Electric        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 379,600 380,200 885,700 842,400
Operating Segments | Residential | PSNH        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 141,100 133,600 323,100 298,600
Operating Segments | Commercial | CL&P        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 309,500 248,000 653,600 500,400
Operating Segments | Commercial | NSTAR Electric        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 377,800 354,400 753,500 727,900
Operating Segments | Commercial | PSNH        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 85,100 81,100 173,400 163,100
Operating Segments | Industrial | CL&P        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 44,000 32,600 92,400 65,800
Operating Segments | Industrial | NSTAR Electric        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 33,200 30,200 64,100 60,100
Operating Segments | Industrial | PSNH        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 25,500 27,100 50,300 51,700
Operating Segments | Wholesale Transmission Revenues | CL&P        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 247,100 218,800 498,200 419,500
Operating Segments | Wholesale Transmission Revenues | NSTAR Electric        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 226,400 200,900 445,100 389,700
Operating Segments | Wholesale Transmission Revenues | PSNH        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 122,900 93,200 247,100 177,800
Operating Segments | Wholesale Market Sales Revenues | CL&P        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 114,700 97,400 394,700 218,600
Operating Segments | Wholesale Market Sales Revenues | NSTAR Electric        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 32,100 27,000 89,400 58,600
Operating Segments | Wholesale Market Sales Revenues | PSNH        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 8,400 7,600 18,800 20,100
Operating Segments | Other Revenues from Contracts with Customers | CL&P        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 8,600 1,500 17,200 18,000
Operating Segments | Other Revenues from Contracts with Customers | NSTAR Electric        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 12,300 13,300 24,300 24,400
Operating Segments | Other Revenues from Contracts with Customers | PSNH        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 5,100 5,500 9,500 10,700
Other        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 405,800 395,200 844,900 838,800
Alternative Revenue Programs 0 0 0 0
Other Revenues 0 0 0 0
Total Operating Revenues 405,800 395,200 844,900 838,800
Other | Total Retail Tariff Sales Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 0 0 0 0
Other | Residential        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 0 0 0 0
Other | Commercial        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 0 0 0 0
Other | Industrial        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 0 0 0 0
Other | Wholesale Transmission Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 0 0 0 0
Other | Wholesale Market Sales Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 0 0 0 0
Other | Other Revenues from Contracts with Customers        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 405,800 395,200 844,900 838,800
Eliminations        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers (852,900) (797,300) (1,735,900) (1,607,200)
Alternative Revenue Programs 28,200 (15,800) 73,400 (42,600)
Other Revenues 0 0 0 0
Total Operating Revenues (824,700) (813,100) (1,662,500) (1,649,800)
Eliminations | Total Retail Tariff Sales Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers (8,700) (7,500) (16,600) (14,300)
Eliminations | Residential        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 0 0 0 0
Eliminations | Commercial        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers (1,900) (1,500) (4,000) (3,200)
Eliminations | Industrial        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers (6,800) (6,000) (12,600) (11,100)
Eliminations | Wholesale Transmission Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers (439,600) (396,100) (878,900) (757,700)
Eliminations | Wholesale Market Sales Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 0 0 0 0
Eliminations | Other Revenues from Contracts with Customers        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers (404,600) (393,700) (840,400) (835,200)
Consolidations Eliminations | CL&P        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues (178,500) (172,800) (354,600) (332,600)
Consolidations Eliminations | NSTAR Electric        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues (186,800) (166,700) (366,500) (326,000)
Consolidations Eliminations | PSNH        
Disaggregation of Revenue [Line Items]        
Total Operating Revenues (66,800) (64,800) (134,100) (121,000)
Electric Distribution | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 2,156,000 1,948,700 4,925,600 4,191,700
Alternative Revenue Programs 7,600 14,000 9,800 27,300
Other Revenues 2,800 3,600 8,700 9,000
Total Operating Revenues 2,166,400 1,966,300 4,944,100 4,228,000
Electric Distribution | Operating Segments | Total Retail Tariff Sales Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 1,978,600 1,800,600 4,379,700 3,849,900
Electric Distribution | Operating Segments | Residential        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 1,104,200 1,027,500 2,593,600 2,281,600
Electric Distribution | Operating Segments | Commercial        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 771,700 683,200 1,579,300 1,390,700
Electric Distribution | Operating Segments | Industrial        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 102,700 89,900 206,800 177,600
Electric Distribution | Operating Segments | Wholesale Transmission Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 0 0 0 0
Electric Distribution | Operating Segments | Wholesale Market Sales Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 155,200 132,000 502,900 297,300
Electric Distribution | Operating Segments | Other Revenues from Contracts with Customers        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 22,200 16,100 43,000 44,500
Natural Gas Distribution | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 457,800 392,600 1,591,800 1,266,400
Alternative Revenue Programs 2,300 200 8,600 31,600
Other Revenues 700 700 1,700 1,500
Total Operating Revenues 460,800 393,500 1,602,100 1,299,500
Natural Gas Distribution | Operating Segments | Total Retail Tariff Sales Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 407,300 356,100 1,477,600 1,170,500
Natural Gas Distribution | Operating Segments | Residential        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 234,100 204,100 930,600 711,700
Natural Gas Distribution | Operating Segments | Commercial        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 125,500 116,400 431,500 363,400
Natural Gas Distribution | Operating Segments | Industrial        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 47,700 35,600 115,500 95,400
Natural Gas Distribution | Operating Segments | Wholesale Transmission Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 0 0 0 0
Natural Gas Distribution | Operating Segments | Wholesale Market Sales Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 48,900 35,000 111,300 93,300
Natural Gas Distribution | Operating Segments | Other Revenues from Contracts with Customers        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 1,600 1,500 2,900 2,600
Electric Transmission | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 599,700 516,500 1,197,300 994,600
Alternative Revenue Programs (31,100) 17,500 (81,000) 47,000
Other Revenues 100 100 200 300
Total Operating Revenues 568,700 534,100 1,116,500 1,041,900
Electric Transmission | Operating Segments | Total Retail Tariff Sales Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 0 0 0 0
Electric Transmission | Operating Segments | Residential        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 0 0 0 0
Electric Transmission | Operating Segments | Commercial        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 0 0 0 0
Electric Transmission | Operating Segments | Industrial        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 0 0 0 0
Electric Transmission | Operating Segments | Wholesale Transmission Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 596,400 512,900 1,190,400 987,000
Electric Transmission | Operating Segments | Wholesale Market Sales Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 0 0 0 0
Electric Transmission | Operating Segments | Other Revenues from Contracts with Customers        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 3,300 3,600 6,900 7,600
Water Distribution | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 61,400 59,600 110,600 107,800
Alternative Revenue Programs (600) (2,400) 100 (700)
Other Revenues 300 300 600 600
Total Operating Revenues 61,100 57,500 111,300 107,700
Water Distribution | Operating Segments | Total Retail Tariff Sales Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 59,600 57,100 107,200 104,600
Water Distribution | Operating Segments | Residential        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 40,700 37,800 72,000 68,000
Water Distribution | Operating Segments | Commercial        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 17,700 18,200 33,100 34,400
Water Distribution | Operating Segments | Industrial        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 1,200 1,100 2,100 2,200
Water Distribution | Operating Segments | Wholesale Transmission Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 0 0 0 0
Water Distribution | Operating Segments | Wholesale Market Sales Revenues        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers 1,100 1,000 2,100 1,900
Water Distribution | Operating Segments | Other Revenues from Contracts with Customers        
Disaggregation of Revenue [Line Items]        
Revenues from Contracts with Customers $ 700 $ 1,500 $ 1,300 $ 1,300