DERIVATIVE INSTRUMENTS - DERIVATIVE ASSETS AND LIABILITIES (Details) $ in Millions	Mar. 31, 2025 USD ($) Instruments	Dec. 31, 2024 USD ($) Instruments
Derivative assets
Current derivative assets	$ 81.2	$ 37.0
Derivative assets	$ 88.6	$ 41.1
Current derivative assets balance sheet location	Other	Other
Long-term derivative assets balance sheet location	Other Assets, Noncurrent	Other Assets, Noncurrent
Derivative liabilities
Current derivative liabilities	$ 4.9	$ 13.9
Derivative liabilities	$ 4.9	$ 13.9
Current derivative liabilities balance sheet location	Other Liabilities, Current	Other Liabilities, Current
Long-term derivative liabilities balance sheet location	Other noncurrent liabilities	Other noncurrent liabilities
Natural gas contracts
Derivative assets
Current derivative assets	$ 78.2	$ 29.2
Long-term derivative assets	7.4	4.1
Derivative liabilities
Current derivative liabilities	4.9	13.9
Long-term derivative liabilities	0.0	0.0
FTRs and TCRs
Derivative assets
Current derivative assets	3.0	7.8
Derivative liabilities
Current derivative liabilities	$ 0.0	$ 0.0
Designated as hedging instrument
Derivative instruments
Number of derivative instruments \| Instruments	0	0

Indicates line item in statement of financial position that includes derivative asset classified as current.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-4A

+ Details

Name:	us-gaap_DerivativeAssetCurrentStatementOfFinancialPositionExtensibleEnumeration
Namespace Prefix:	us-gaap_
Data Type:	enum2:enumerationSetItemType
Balance Type:	na
Period Type:	instant

- Definition

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and elected not to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 320
-Name Accounting Standards Codification
-Section S99
-Paragraph 5C
-Subparagraph (SX 210.12-13C(Column F))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5C

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 320
-Name Accounting Standards Codification
-Section S99
-Paragraph 5B
-Subparagraph (SX 210.12-13B(Column E))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5B

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 210
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483444/210-20-55-22

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483466/210-20-50-3

+ Details

Name:	us-gaap_DerivativeAssetFairValueGrossAssetIncludingNotSubjectToMasterNettingArrangement
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Indicates line item in statement of financial position that includes derivative asset classified as noncurrent.

+ References

+ Details

Name:	us-gaap_DerivativeAssetNoncurrentStatementOfFinancialPositionExtensibleEnumeration
Namespace Prefix:	us-gaap_
Data Type:	enum2:enumerationSetItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_DerivativeAssetsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying amount as of the balance sheet date of the asset arising from derivative instruments and hedging activities, which are expected to be converted into cash or otherwise disposed of within a year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(8))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_DerivativeInstrumentsAndHedges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value of liability arising from contracts that meet the criteria of being accounted for as derivative instruments, financial instrument or contract used to mitigate a specified risk (hedge), energy marketing activities (trading activities), expected to be settled after one year or beyond the normal operating cycle, if longer. Examples of energy marketing activities include, but are not limited to, trading of electricity, coal, natural gas and oil using financial instruments, including, but not limited to, forward contracts, options and swaps.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeInstrumentsAndHedgesLiabilitiesNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying amount as of the balance sheet date of the assets arising from derivative contracts and hedging activities, which are expected to be converted into cash or otherwise disposed of after a year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(17))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_DerivativeInstrumentsAndHedgesNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_DerivativeLiabilitiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Indicates line item in statement of financial position that includes derivative liability classified as current.

+ References

+ Details

Name:	us-gaap_DerivativeLiabilityCurrentStatementOfFinancialPositionExtensibleEnumeration
Namespace Prefix:	us-gaap_
Data Type:	enum2:enumerationSetItemType
Balance Type:	na
Period Type:	instant

- Definition

Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and elected not to be offset.

+ References

+ Details

Name:	us-gaap_DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangement
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Indicates line item in statement of financial position that includes derivative liability classified as noncurrent.

+ References

+ Details

Name:	us-gaap_DerivativeLiabilityNoncurrentStatementOfFinancialPositionExtensibleEnumeration
Namespace Prefix:	us-gaap_
Data Type:	enum2:enumerationSetItemType
Balance Type:	na
Period Type:	instant

- 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/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480237/815-40-50-5

+ Details

Name:	us-gaap_DerivativeLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of derivative instruments of a particular group held by the entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 210
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478795/946-210-50-6

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 946
-SubTopic 210
-Name Accounting Standards Codification
-Section 55
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477439/946-210-55-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 320
-Name Accounting Standards Codification
-Section S99
-Paragraph 5
-Subparagraph (SX 210.12-13(Column A)(Footnote 3))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 320
-Name Accounting Standards Codification
-Section S99
-Paragraph 5
-Subparagraph (SX 210.12-13(Column C))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 320
-Name Accounting Standards Codification
-Section S99
-Paragraph 5A
-Subparagraph (SX 210.12-13A(Column B))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5A

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-1B

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-1A

+ Details

Name:	us-gaap_DerivativeNumberOfInstrumentsHeld
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Carrying amount as of the balance sheet date of the liability arising from a financial instrument or a contract used to mitigate a specified risk (hedge), and which are expected to be converted into cash or otherwise disposed of within a year or the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(20))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_HedgingLiabilitiesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=wec_CommodityContractNaturalGasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=wec_CommodityContractTransmissionCongestionRightsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: