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

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=121555522&loc=d3e12069-110248

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

Represents the maximum potential payments with respect to the entity's guarantees that expire in less than a year.

No definition available.

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

Represents the maximum potential payments with respect to the entity's guarantees that expire after three years.

No definition available.

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

Represents the maximum potential payments with respect to the entity's guarantees that expire within one to three years.

No definition available.

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

Name:	us-gaap_GuaranteeObligationsByNatureAxis=wec_CommodityTransactionsGuaranteeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

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

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

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

Name:	us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_StandbyLettersOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_SuretyBondMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_GuaranteeTypeOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: