XML 172 R144.htm IDEA: XBRL DOCUMENT
v3.25.0.1

COMMITMENTS AND CONTINGENCIES - Schedule of Number of Sites and Reserves (Details) - site | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023
Loss Contingencies [Line Items] |  |
Number of Sites | 65 | 65
CL&P |  |
Loss Contingencies [Line Items] |  |
Number of Sites | 15 | 16
NSTAR Electric |  |
Loss Contingencies [Line Items] |  |
Number of Sites | 14 | 12
PSNH |  |
Loss Contingencies [Line Items] |  |
Number of Sites | 8 | 8

X
- Definition Number of environmental sites by NU Entity in the remediation or long-term monitoring phase + References No definition available. + Details
Name: | es_EnvironmentalSiteQuantity
Namespace Prefix: | es_
Data Type: | xbrli:integerItemType
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 Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483076/450-20-50-4 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483076/450-20-50-9 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 720 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483359/720-20-50-1 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Topic 460 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 27 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482395/460-10-55-27 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483076/450-20-50-9 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483076/450-20-50-4 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 460 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482425/460-10-50-3 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483076/450-20-50-1 + Details
Name: | us-gaap_LossContingenciesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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: |