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EMPLOYEE BENEFITS - Schedule of Other Retirement Benefits (Details) - USD ($) $ in Millions | Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
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Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Actuarially-Determined Liability | $ 30.2 | $ 32.6 | $ 43.4
Other Retirement Benefits Expense | 2.4 | 2.6 | 10.9
Retirement benefit payable |  | 9.2 |
CL&P |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Actuarially-Determined Liability | 0.1 | 0.2 | 0.2
Other Retirement Benefits Expense | 0.8 | 0.8 | 4.0
NSTAR Electric |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Actuarially-Determined Liability | 0.0 | 0.0 | 0.1
Other Retirement Benefits Expense | 0.8 | 0.8 | 3.7
PSNH |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Actuarially-Determined Liability | 1.0 | 1.1 | 1.3
Other Retirement Benefits Expense | $ 0.3 | $ 0.4 | $ 1.3

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- Definition Aggregate carrying value as of the balance sheet date of the liabilities for deferred compensation arrangements payable after one year (or the normal operating cycle, if longer). Represents currently earned compensation under cash arrangements (such as a profit-sharing plan, rabbi trust, and employee contract--excluding equity-based arrangements) that is not actually paid until a later date. + References No definition available. + Details
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- Definition Amount of liability, recognized in statement of financial position, for pension, other postretirement and postemployment benefits. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(15)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480535/715-20-45-2 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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