The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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COMMITMENTS AND CONTINGENCIES - Guarantees and Indemnifications (Details) - USD ($)	Sep. 30, 2020	Sep. 16, 2020	Oct. 25, 2019
Sunrise Wind, LLC
Guarantor Obligations [Line Items]
Maximum exposure (up to)			$ 15,400,000
Ownership interest			50.00%
Surety Bond
Guarantor Obligations [Line Items]
Maximum exposure (up to)	$ 30,900,000
Lease Payments for Real Estate
Guarantor Obligations [Line Items]
Maximum exposure (up to)	5,600,000
Real Estate Purchase
Guarantor Obligations [Line Items]
Maximum exposure (up to)	2,500,000
Sunrise Wind, LLC - Offshore Wind
Guarantor Obligations [Line Items]
Maximum exposure (up to)	$ 2,200,000
Letter of Credit Guarantee \| Eversource Investment, LLC
Guarantor Obligations [Line Items]
Maximum exposure (up to)		$ 25,000,000