XML 117 R82.htm IDEA: XBRL DOCUMENT
v3.22.0.1

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Fuel, Materials, Supplies and Inventory (Details) - USD ($) $ in Millions | Dec. 31, 2021 | Dec. 31, 2020
--- | --- | ---
Public Utilities, Inventory [Line Items] |  |
Total | $ 267.5 | $ 265.6
Fuel |  |
Public Utilities, Inventory [Line Items] |  |
Other inventory, capitalized costs, gross | 56.2 | 38.2
Materials and Supplies |  |
Public Utilities, Inventory [Line Items] |  |
Other inventory, capitalized costs, gross | 148.9 | 151.3
RECs |  |
Public Utilities, Inventory [Line Items] |  |
Other inventory, capitalized costs, gross | 62.4 | 76.1
The Connecticut Light and Power Company |  |
Public Utilities, Inventory [Line Items] |  |
Total | 60.3 | 57.9
The Connecticut Light and Power Company | Fuel |  |
Public Utilities, Inventory [Line Items] |  |
Other inventory, capitalized costs, gross | 0.0 | 0.0
The Connecticut Light and Power Company | Materials and Supplies |  |
Public Utilities, Inventory [Line Items] |  |
Other inventory, capitalized costs, gross | 60.3 | 57.9
The Connecticut Light and Power Company | RECs |  |
Public Utilities, Inventory [Line Items] |  |
Other inventory, capitalized costs, gross | 0.0 | 0.0
NSTAR Electric Company |  |
Public Utilities, Inventory [Line Items] |  |
Total | 116.7 | 133.9
NSTAR Electric Company | Fuel |  |
Public Utilities, Inventory [Line Items] |  |
Other inventory, capitalized costs, gross | 0.0 | 0.0
NSTAR Electric Company | Materials and Supplies |  |
Public Utilities, Inventory [Line Items] |  |
Other inventory, capitalized costs, gross | 55.0 | 62.1
NSTAR Electric Company | RECs |  |
Public Utilities, Inventory [Line Items] |  |
Other inventory, capitalized costs, gross | 61.7 | 71.8
Public Service Company of New Hampshire |  |
Public Utilities, Inventory [Line Items] |  |
Total | 25.9 | 26.8
Public Service Company of New Hampshire | Fuel |  |
Public Utilities, Inventory [Line Items] |  |
Other inventory, capitalized costs, gross | 0.0 | 0.0
Public Service Company of New Hampshire | Materials and Supplies |  |
Public Utilities, Inventory [Line Items] |  |
Other inventory, capitalized costs, gross | 25.2 | 22.5
Public Service Company of New Hampshire | RECs |  |
Public Utilities, Inventory [Line Items] |  |
Other inventory, capitalized costs, gross | $ 0.7 | $ 4.3

X
- Definition Gross amount, as of the balance sheet date, of merchandise, goods, commodities, or supplies held for future sale or to be used in manufacturing, servicing or production process. + 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 210.5-02.6(a)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_InventoryGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, before valuation and last-in first out (LIFO) reserves, of costs capitalized in inventory classified as other, expected to be sold, or consumed within one year or operating cycle, if longer. + 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 210.5-02.6(a) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_OtherInventoryCapitalizedCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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_PublicUtilitiesInventoryLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | es_TypeOfInventoryByMajorAssetClassAxis=us-gaap_PublicUtilitiesInventoryFuelMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | es_TypeOfInventoryByMajorAssetClassAxis=es_MaterialsandSuppliesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | es_TypeOfInventoryByMajorAssetClassAxis=es_RecsMemberMember
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: |