COMMITMENTS AND CONTINGENCIES - Long-Term Contractual Arrangements (Details) - Milestone Nuclear Power Station MWh in Millions	Mar. 15, 2019 megawatt	Dec. 28, 2018 MWh
Long-term Purchase Commitment [Line Items]
Annual purchase requirement (in MWh) \| MWh		9
Percent of the facility's output required to be purchased	50.00%
Nameplate capacity (in megawatts) \| megawatt	2,112
CL&P
Long-term Purchase Commitment [Line Items]
Contract term	10 years	10 years
Percent of the facility's output required to be purchased	40.00%
UI
Long-term Purchase Commitment [Line Items]
Contract term	10 years	10 years

Long-Term Purchase Commitment, Energy Production Capacity

No definition available.

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- Definition

Share of plant output being purchased under a long-term contract to purchase electricity from a production plant constructed and financed by a public utility district, cooperative, or other organization.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 10.D)
-URI http://asc.fasb.org/extlink&oid=6499423&loc=d3e659339-123030

+ 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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- Definition

Energy volume that must be purchased within the specified time period of the agreement to avoid penalties or unfavorable effects on pricing, among other adverse consequences.

+ References

No definition available.

+ Details

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- Definition

Period covered by the long-term purchase commitment, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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