XML 147 R112.htm IDEA: XBRL DOCUMENT
v3.22.0.1

LONG-TERM DEBT - Narrative (Details) - USD ($) $ in Thousands | Dec. 31, 2021 | Sep. 10, 2021 | Mar. 31, 2021 | Dec. 31, 2020
--- | --- | --- | --- | ---
Debt Instrument [Line Items] |  |  |  |
Long-term debt | $ 17,023,577 |  |  | $ 15,125,876
Interest included in payment to settle spent nuclear fuel obligation |  |  |  | 8,700
Pre-1983 Spent Nuclear Fuel Obligation (CYAPC) |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Long-term debt | 11,700 |  |  | 11,700
NSTAR Electric Company |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Amount of long-term debt requested for issuance |  |  | $ 1,600,000 |
Long-term debt | $ 3,585,399 |  |  | $ 3,393,221
Massachusetts Department of Public Utilities |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Amount of long-term debt requested for issuance |  | $ 725,000 |  |

X
- Definition Debt Instrument, Requested For Issuance, Face Amount + References No definition available. + Details
Name: | es_DebtInstrumentRequestedForIssuanceFaceAmount
Namespace Prefix: | es_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount represents the interest included in the payment to settle the spent nuclear fuel obligation + References No definition available. + Details
Name: | es_InterestIncludedInPaymentToSettleSpentNuclearFuelObligation
Namespace Prefix: | es_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_LongTermDebtNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=es_SpentNuclearFuelObilgationCyMember
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_MassachusettsDepartmentOfPublicUtilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |