XML 128 R100.htm IDEA: XBRL DOCUMENT
v3.24.0.1

MARKETABLE SECURITIES - Fair Value Measurement (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022
--- | --- | ---
Debt and Equity Securities, FV-NI [Line Items] |  |
Total Marketable Securities | $ 341.2 | $ 375.6
Level 1 |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Total Marketable Securities | 190.6 | 215.5
Level 1 | Mutual Funds and Equities |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Total Marketable Securities | 176.9 | 190.1
Level 1 | Money Market Funds |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Total Marketable Securities | 13.7 | 25.4
Level 2 |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Total Marketable Securities | 150.6 | 160.1
Level 2 | U.S. Government Issued Debt Securities (Agency and Treasury) |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Total Marketable Securities | 90.1 | 82.3
Level 2 | Corporate Debt Securities |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Total Marketable Securities | 34.0 | 46.1
Level 2 | Asset-Backed Debt Securities |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Total Marketable Securities | 5.6 | 8.6
Level 2 | Municipal Bonds |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Total Marketable Securities | 9.8 | 12.7
Level 2 | Other Fixed Income Securities |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Total Marketable Securities | $ 11.1 | $ 10.4

X
- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_InvestmentsFairValueDisclosure
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_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=es_MutualFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CashAndCashEquivalentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CorporateBondSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_MunicipalBondsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_OtherDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |