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v3.25.0.1

LONG-TERM DEBT - Schedule of Issuances and Repayments (Details) - USD ($) $ in Thousands | 1 Months Ended | 12 Months Ended
--- | --- | ---
Jan. 31, 2025 | Oct. 31, 2024 | Aug. 31, 2024 | Jul. 31, 2024 | Jun. 30, 2024 | May 31, 2024 | Apr. 30, 2024 | Jan. 31, 2024 | Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Repayments of debt |  |  |  |  |  |  |  |  | $ (1,949,995) | $ (2,008,470) | $ (1,175,000)
CL&P |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Repayments of debt |  |  |  |  |  |  |  |  | (139,800) | (400,000) | 0
NSTAR Electric |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Repayments of debt |  |  |  |  |  |  |  |  | 0 | (80,000) | (400,000)
PSNH |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Repayments of debt |  |  |  |  |  |  |  |  | 0 | (325,000) | 0
CL&P 2024 Series A First Mortgage Bonds | First Mortgage Bonds | CL&P |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  |  |  |  |  |  |  | 4.65% |  |  |
Issuance |  |  |  |  |  |  |  | $ 350,000 |  |  |
CL&P Series B First Mortgage Bonds | First Mortgage Bonds | CL&P |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  |  | 4.95% |  |  |  |  |  |  |  |
Issuance |  |  | $ 300,000 |  |  |  |  |  |  |  |
CL&P Series D First Mortgage Bonds | First Mortgage Bonds | CL&P |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  | 7.875% |  |  |  |  |  |  |  |  |
Repayments of debt |  | $ (139,800) |  |  |  |  |  |  |  |  |
CL&P 2025 Series A First Mortgage Bonds | First Mortgage Bonds | CL&P | Subsequent Event |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate | 4.95% |  |  |  |  |  |  |  |  |  |
Issuance | $ 400,000 |  |  |  |  |  |  |  |  |  |
NSTAR Electric Debentures | Unsecured Debt | NSTAR Electric |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  |  |  |  |  | 5.40% |  |  |  |  |
Issuance |  |  |  |  |  | $ 600,000 |  |  |  |  |
PSNH Series X First Mortgage Bonds | First Mortgage Bonds | PSNH |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  |  |  |  |  |  | 5.35% |  |  |  |
Issuance |  |  |  |  |  |  | $ 300,000 |  |  |  |
NSTAR Gas Series W First Mortgage Bonds | First Mortgage Bonds | NSTAR Gas |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  |  |  |  | 5.29% |  |  |  |  |  |
Issuance |  |  |  |  | $ 160,000 |  |  |  |  |  |
NSTAR Gas Series X First Mortgage Bonds | First Mortgage Bonds | NSTAR Gas |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  |  |  |  | 5.48% |  |  |  |  |  |
Issuance |  |  |  |  | $ 40,000 |  |  |  |  |  |
Yankee Gas Series W First Mortgage Bonds | First Mortgage Bonds | Yankee Gas Services Company |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  |  |  | 5.50% |  |  |  |  |  |  |
Issuance |  |  |  | $ 90,000 |  |  |  |  |  |  |
Yankee Gas Series X First Mortgage Bonds | First Mortgage Bonds | Yankee Gas Services Company |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  |  |  | 5.74% |  |  |  |  |  |  |
Issuance |  |  |  | $ 90,000 |  |  |  |  |  |  |
Yankee Gas Series P First Mortgage Bonds | First Mortgage Bonds | Yankee Gas Services Company |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  | 2.23% |  |  |  |  |  |  |  |  |
Repayments of debt |  | $ (100,000) |  |  |  |  |  |  |  |  |
EGMA Series E First Mortgage Bonds | First Mortgage Bonds | Eversource Gas Company of Massachusetts |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  | 5.17% |  |  |  |  |  |  |  |  |
Issuance |  | $ 100,000 |  |  |  |  |  |  |  |  |
Aquarion Senior Notes | Senior Notes | Aquarion Company and its Subsidiaries |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  |  | 4.00% |  |  |  |  |  |  |  |
Repayments of debt |  |  | $ (360,000) |  |  |  |  |  |  |  |
Aquarion Water Company of Connecticut Senior Notes | Senior Notes | Aquarion Company and its Subsidiaries |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  |  | 5.57% |  |  |  |  |  |  |  |
Issuance |  |  | $ 70,000 |  |  |  |  |  |  |  |
Eversource |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Repayments of debt |  |  |  |  |  |  |  |  | $ (1,350,000) | $ (1,200,000) | $ (750,000)
Eversource | Eversource Parent Series DD Senior Notes | Senior Notes |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  |  |  |  |  |  |  | 5.00% |  |  |
Issuance |  |  |  |  |  |  |  | $ 350,000 |  |  |
Eversource | Eversource Parent Series EE Senior Notes | Senior Notes |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  |  |  |  |  |  |  | 5.50% |  |  |
Issuance |  |  |  |  |  |  |  | $ 650,000 |  |  |
Eversource | Eversource Parent Series FF Senior Notes | Senior Notes |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  |  |  |  |  |  | 5.85% |  |  |  |
Issuance |  |  |  |  |  |  | $ 700,000 |  |  |  |
Eversource | Eversource Parent Series GG Senior Notes | Senior Notes |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  |  |  |  |  |  | 5.95% |  |  |  |
Issuance |  |  |  |  |  |  | $ 700,000 |  |  |  |
Eversource | Eversource Parent Series X Senior Notes | Senior Notes |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  |  |  |  | 4.20% |  |  |  |  |  |
Repayments of debt |  |  |  |  | $ (900,000) |  |  |  |  |  |
Eversource | Eversource Parent Series L Senior Notes | Senior Notes |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate |  | 2.90% |  |  |  |  |  |  |  |  |
Repayments of debt |  | $ (450,000) |  |  |  |  |  |  |  |  |
Eversource | Eversource Parent Series H Senior Notes | Senior Notes | Subsequent Event |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |
Interest rate | 3.15% |  |  |  |  |  |  |  |  |  |
Repayments of debt | $ (300,000) |  |  |  |  |  |  |  |  |  |

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