XML 92 R73.htm IDEA: XBRL DOCUMENT
v3.23.2

DERIVATIVE INSTRUMENTS - Narrative (Details) - MW | 6 Months Ended |
--- | --- | ---
Jun. 30, 2023 | Dec. 31, 2022
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Percentage of costs or benefits borne under capacity-related contracts by United Illuminated Company (in percent) | 20.00% |
Amount of power to be purchased under capacity-related contract (in MW) | 674 | 674
Level 3 | Minimum |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Percentage of exit price premiums related to derivative contracts (in percentage) | 1.80% |
Level 3 | Maximum |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Percentage of exit price premiums related to derivative contracts (in percentage) | 6.10% |
Level 3 | Weighted Average |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Percentage of exit price premiums related to derivative contracts (in percentage) | 5.00% |
CL&P |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Percentage of costs or benefits borne under capacity-related contracts (in percent) | 80.00% |

X
- Definition Amount of Capacity Provided Under Capacity Contract + References No definition available. + Details
Name: | es_AmountOfCapacityProvidedUnderCapacityContract
Namespace Prefix: | es_
Data Type: | dtr-types1:powerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of Costs Or Benefits Borne Under Capacity-Related Contracts + References No definition available. + Details
Name: | es_PercentageOfCostsOrBenefitsBorneUnderCapacityRelatedContracts
Namespace Prefix: | es_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage Of Costs Or Benefits Borne Under Capacity-Related Contracts By United Illuminated Company + References No definition available. + Details
Name: | es_PercentageOfCostsOrBenefitsBorneUnderCapacityRelatedContractsByUnitedIlluminatedCompany
Namespace Prefix: | es_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of Exit Price Premiums + References No definition available. + Details
Name: | es_PercentageofExitPricePremiums
Namespace Prefix: | es_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | duration

X
- 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
Name: | us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_WeightedAverageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=es_TheConnecticutLightAndPowerCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |