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ASSET RETIREMENT OBLIGATIONS (Tables) | 12 Months Ended
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Dec. 31, 2023
Asset Retirement Obligation Disclosure [Abstract] |
Schedule of Change in Asset Retirement Obligation | A reconciliation of the beginning and ending carrying amounts of ARO liabilities is as follows:
| As of December 31,
| 2023 |  | 2022
(Millions of Dollars) | Eversource |  | CL&P |  | NSTAR Electric |  | PSNH |  | Eversource |  | CL&P |  | NSTAR Electric |  | PSNH
Balance as of Beginning of Year | $ | 502.7 |  |  | $ | 37.4 |  |  | $ | 101.3 |  |  | $ | 4.9 |  |  | $ | 500.1 |  |  | $ | 35.0 |  |  | $ | 97.5 |  |  | $ | 4.7 |
Liabilities Settled During the Year | (24.9) |  |  | — |  |  | — |  |  | — |  |  | (22.3) |  |  | — |  |  | — |  |  | — |
Accretion | 29.2 |  |  | 2.5 |  |  | 4.3 |  |  | 0.3 |  |  | 28.9 |  |  | 2.4 |  |  | 4.1 |  |  | 0.2 |
Revisions in Estimated Cash Flows | (1.2) |  |  | — |  |  | (0.8) |  |  | — |  |  | (4.0) |  |  | — |  |  | (0.3) |  |  | — |
Balance as of End of Year | $ | 505.8 |  |  | $ | 39.9 |  |  | $ | 104.8 |  |  | $ | 5.2 |  |  | $ | 502.7 |  |  | $ | 37.4 |  |  | $ | 101.3 |  |  | $ | 4.9 |

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- Definition Tabular disclosure of the changes in carrying amount of a liability for asset retirement obligations, for changes such as new obligations, changes in estimates of existing obligations, spending on existing obligations, property dispositions, and foreign currency translation. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481850/410-20-50-1 + Details
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