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COMMITMENTS AND CONTINGENCIES - Schedule of Total Costs Incurred (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Long-term Purchase Commitment [Line Items] |  |  |
Renewable Energy | $ 609.2 | $ 584.2 | $ 320.8
Natural Gas Procurement | 712.7 | 453.4 | 448.5
Purchased Power and Capacity | 56.4 | 62.7 | 62.1
Peaker CfDs | 24.3 | 22.7 | 13.0
Transmission Support Commitments | 15.4 | 22.1 | 21.8
The Connecticut Light and Power Company |  |  |
Long-term Purchase Commitment [Line Items] |  |  |
Renewable Energy | 457.1 | 426.3 | 160.6
Purchased Power and Capacity | 53.1 | 59.3 | 50.4
Peaker CfDs | 24.3 | 22.7 | 13.0
Transmission Support Commitments | 6.1 | 8.7 | 8.6
NSTAR Electric Company |  |  |
Long-term Purchase Commitment [Line Items] |  |  |
Renewable Energy | 84.7 | 88.8 | 89.9
Purchased Power and Capacity | 3.0 | 3.1 | 5.1
Peaker CfDs | 0.0 | 0.0 | 0.0
Transmission Support Commitments | 6.0 | 8.7 | 8.6
Public Service Company of New Hampshire |  |  |
Long-term Purchase Commitment [Line Items] |  |  |
Renewable Energy | 67.4 | 69.1 | 70.3
Purchased Power and Capacity | 0.3 | 0.3 | 6.6
Peaker CfDs | 0.0 | 0.0 | 0.0
Transmission Support Commitments | $ 3.3 | $ 4.7 | $ 4.6

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