XML 48 R37.htm IDEA: XBRL DOCUMENT
v3.7.0.1

ACQUISITION (Details) - Natural gas storage facility in Michigan - USD ($) $ in Millions | 1 Months Ended |
--- | --- | ---
Jan. 31, 2017 | Mar. 31, 2017
Business Acquisition [Line Items] |  |
Purchase price | $ 225 |
Percentage of current storage needs provided |  | 33.00%
Expected acquisition costs |  | $ 5

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_BusinessAcquisitionLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477 + Details
Name: | us-gaap_BusinessCombinationConsiderationTransferred1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of acquisition costs expected to be incurred + References No definition available. + Details
Name: | wec_Expectedacquisitioncosts
Namespace Prefix: | wec_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Percentage of storage needs provided + References No definition available. + Details
Name: | wec_Percentageofstorageneedsprovided
Namespace Prefix: | wec_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=wec_NaturalgasstoragefacilityinMichiganMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |