ACQUISITION OF ASSETS OF COLUMBIA GAS OF MASSACHUSETTS - Narrative (Details) - CMA $ in Millions	Oct. 09, 2020 USD ($)
Business Acquisition [Line Items]
Cash purchase price	$ 1,100.0
Target working capital amount	$ 68.6

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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