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EMPLOYEE BENEFITS - Schedule of Defined Contribution Plans (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Defined Contribution Plan Disclosure [Line Items] |  |  |
Defined contribution plan, cost recognized | $ 55.5 | $ 49.4 | $ 41.6
The Connecticut Light and Power Company |  |  |
Defined Contribution Plan Disclosure [Line Items] |  |  |
Defined contribution plan, cost recognized | 7.0 | 6.6 | 5.5
NSTAR Electric Company |  |  |
Defined Contribution Plan Disclosure [Line Items] |  |  |
Defined contribution plan, cost recognized | 12.2 | 11.8 | 10.3
Public Service Company of New Hampshire |  |  |
Defined Contribution Plan Disclosure [Line Items] |  |  |
Defined contribution plan, cost recognized | $ 4.3 | $ 4.1 | $ 3.5

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- Definition Amount of cost for defined contribution plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Details
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