XML 184 R149.htm IDEA: XBRL DOCUMENT
v3.22.0.1

COMMITMENTS AND CONTINGENCIES - FERC ROE Complaints (Details) $ in Millions |  |  | 12 Months Ended | 30 Months Ended | 36 Months Ended |  |
--- | --- | --- | --- | --- | --- | --- | ---
Oct. 16, 2018 complaint | Apr. 29, 2016 complaint | Dec. 31, 2021 USD ($) | Apr. 14, 2017 | Oct. 15, 2014 | Dec. 31, 2020 USD ($) | Jul. 31, 2014 complaint
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Percentage of base ROE reasonably justified | 10.41% |  |  |  |  |  |
Percentage of incentive cap on total ROE | 13.08% |  |  |  |  |  |
FERC ROE Complaints |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Loss contingency, pending claims, number | complaint | 4 | 4 |  |  |  |  |
Period of complaint |  |  | 15 months |  |  |  |
Basis point change |  |  | 0.10% |  |  |  |
Estimate of possible loss for each 10 basis point change to base ROE |  |  | $ 3.0 |  |  |  |
FERC ROE First, Second and Third Complaints |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Loss contingency, pending claims, number | complaint |  |  |  |  |  |  | 3
Base ROE percentage challenged by complainants |  |  | 11.14% |  |  |  |
Percentage of ROE for any incentive project | 13.08% |  |  |  |  |  |
FERC ROE First Complaint |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Percentage of ROE for any incentive project |  |  |  | 11.74% |  |  |
Refund payments |  |  | $ 38.9 |  |  |  |
FERC ROE Second Complaint |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Percentage of base ROE of complaint period |  |  | 10.57% | 10.57% |  |  |
Percentage of ROE for any incentive project |  |  | 11.74% |  |  |  |
Loss contingency, estimate of possible earnings impact |  |  | $ 39.1 |  |  |  |
FERC ROE Fourth Complaint |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Percentage of base ROE of complaint period |  | 10.57% |  |  |  |  |
Maximum percentage cap of ROE for incentive projects |  | 11.74% |  |  |  |  |
Percentage of ROE for any incentive project |  |  | 10.57% |  |  |  |
Original base ROE authorized by FERC at time of complaint |  |  | 11.74% |  |  |  |
The Connecticut Light and Power Company | FERC ROE First Complaint |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Refund payments |  |  | $ 22.4 |  |  |  |
The Connecticut Light and Power Company | FERC ROE Second Complaint |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Loss contingency, estimate of possible earnings impact |  |  | 21.4 |  |  | $ 21.4 |
NSTAR Electric Company | FERC ROE First Complaint |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Refund payments |  |  | 13.7 |  |  |  |
NSTAR Electric Company | FERC ROE Second Complaint |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Loss contingency, estimate of possible earnings impact |  |  | 14.6 |  |  | 14.6 |
Public Service Company of New Hampshire | FERC ROE First Complaint |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Refund payments |  |  | 2.8 |  |  |  |
Public Service Company of New Hampshire | FERC ROE Second Complaint |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Loss contingency, estimate of possible earnings impact |  |  | $ 3.1 |  |  | $ 3.1 |
Minimum | FERC ROE First, Second and Third Complaints |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Percentage of ROE for any incentive project |  |  |  |  | 11.14% |  |
Maximum | FERC ROE First, Second and Third Complaints |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Percentage of ROE for any incentive project |  |  |  |  | 13.10% |  |

X
- Definition Estimate of possible loss for each 10 basis point change to base ROE + References No definition available. + Details
Name: | es_Estimateofpossiblelossforeach10basispointchangetobaseROE
Namespace Prefix: | es_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Loss Contingency, Percentage of Base ROE Challenged by Complainants + References No definition available. + Details
Name: | es_LossContingencyBaseROEPercentageChallengedbyComplainants
Namespace Prefix: | es_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loss Contingency, Basis Spread + References No definition available. + Details
Name: | es_LossContingencyBasisSpread
Namespace Prefix: | es_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loss Contingency, Maximum percentage of ROE for incentive projects + References No definition available. + Details
Name: | es_LossContingencyMaximumpercentageofROEforincentiveprojects
Namespace Prefix: | es_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loss Contingency, Original Base ROE Authorized by FERC at Time of Complaint + References No definition available. + Details
Name: | es_LossContingencyOriginalBaseROEAuthorizedbyFERCatTimeofComplaint
Namespace Prefix: | es_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loss Contingency, Percentage Of Base ROE Reasonably Justified + References No definition available. + Details
Name: | es_LossContingencyPercentageOfBaseROEReasonablyJustified
Namespace Prefix: | es_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loss Contingency, Percentage Of Incentive Cap On Total ROE + References No definition available. + Details
Name: | es_LossContingencyPercentageOfIncentiveCapOnTotalROE
Namespace Prefix: | es_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loss Contingency, Percentage of ROE for Any Incentive Project + References No definition available. + Details
Name: | es_LossContingencyPercentageofROEforAnyIncentiveProject
Namespace Prefix: | es_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loss Contingency, Period of Complaint + References No definition available. + Details
Name: | es_LossContingencyPeriodofComplaint
Namespace Prefix: | es_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of Base ROE of Complaint Period + References No definition available. + Details
Name: | es_PercentageofBaseROEofComplaintPeriod
Namespace Prefix: | es_
Data Type: | dtr-types: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_LossContingenciesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Reflects the estimated amount of loss from the specified contingency as of the balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14435-108349 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 9 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14557-108349 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=124440162&loc=d3e12021-110248 + Details
Name: | us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number of pending claims pertaining to a loss contingency. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14435-108349 + Details
Name: | us-gaap_LossContingencyPendingClaimsNumber
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Cash receipts from customers during the current period which are usually for sales of goods and services. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 25 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3536-108585 + Details
Name: | us-gaap_ProceedsFromCustomers
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_LossContingenciesByNatureOfContingencyAxis=es_FERCROEComplaintsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LossContingenciesByNatureOfContingencyAxis=es_FERCROEFirstSecondandThirdComplaintsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LossContingenciesByNatureOfContingencyAxis=es_FERCROEFirstComplaintMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LossContingenciesByNatureOfContingencyAxis=es_FERCROESecondComplaintMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LossContingenciesByNatureOfContingencyAxis=es_FERCROEFourthComplaintMember
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: |

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

X
- Details
Name: | dei_LegalEntityAxis=es_PublicServiceCompanyOfNewHampshirePSNHMember
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: |