Regulatory Environment - PGL (Details) - Illinois Commerce Commission (ICC) - PGL $ in Millions	Dec. 31, 2019 Assurance	Jul. 31, 2019 USD ($)
Public Utilities, General Disclosures [Line Items]
Rate base reduction from settlement of 2015 reconciliation		$ 7.0
Total refunds required to ratepayers from settlement of 2015 reconciliation		$ 7.3
Amount of assurance that PGL's QIP rider costs will be recoverable \| Assurance	0

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.

No definition available.

+ Details

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

- Definition

Amount of disallowed costs for rate making purposes for recently completed plants in regulated industries.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 360
-Section 35
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=6500292&loc=d3e45799-110387

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 360
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 10.E)
-URI http://asc.fasb.org/extlink&oid=115995737&loc=d3e660019-123033

+ Details

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

- Definition

Amount of assurance that the costs incurred under PGL's Qualifying Infrastructure Plant rider will be recoverable.

+ References

No definition available.

+ Details

Name:	wec_AmountOfAssuranceQIPRiderCostsRecoverable
Namespace Prefix:	wec_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The total amount required to be refunded to customers as a result of a legal settlement or order.

+ References

No definition available.

+ Details

Name:	wec_Refundsrequiredtocustomers
Namespace Prefix:	wec_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_RegulatoryAgencyAxis=wec_IllinoisCommerceCommissionICCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=wec_ThePeoplesGasLightAndCokeCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: