XML 108 R97.htm IDEA: XBRL DOCUMENT
v3.10.0.1

REGULATORY ENVIRONMENT (Details) $ in Millions | 1 Months Ended | 3 Months Ended | 9 Months Ended
--- | --- | --- | ---
May 31, 2018 USD ($) MW solar_projects | Mar. 31, 2018 USD ($) | Feb. 28, 2018 USD ($) Filings | Dec. 31, 2017 USD ($) | Nov. 30, 2017 USD ($) | Oct. 31, 2017 USD ($) | Sep. 30, 2017 USD ($) utility | Sep. 30, 2018 customer Assurance | Sep. 30, 2018 customer change Assurance | Sep. 30, 2017
Regulatory environment |  |  |  |  |  |  |  |  |  |
Corporate federal tax rate |  |  |  |  |  |  |  | 21.00% | 21.00% | 35.00%
WE | Public Service Commission of Wisconsin (PSCW) | 2018 and 2019 rates |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |
Approved return on equity (as a percent) |  |  |  |  |  |  | 10.20% |  |  |
Income Statement impact of flow through of repair related deferred tax liabilities | change |  |  |  |  |  |  |  |  | 0 |
WE | Public Service Commission of Wisconsin (PSCW) | 2018 and 2019 rates | Electric rates |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |
Percentage of current tax benefit from Tax Cuts and Jobs Act of 2017 to be used to reduce certain regulatory assets | 80.00% |  |  |  |  |  |  |  |  |
Percent of current tax benefit from Tax Cuts and Jobs Act of 2017 to be returned to customers via bill credits | 20.00% |  |  |  |  |  |  |  |  |
WE | Michigan Public Service Commission (MPSC) |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |
Number of retail electric customers served in Michigan | customer |  |  |  |  |  |  |  | 1 | 1 |
WG | Public Service Commission of Wisconsin (PSCW) | 2018 and 2019 rates |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |
Approved return on equity (as a percent) |  |  |  |  |  |  | 10.30% |  |  |
WPS | Public Service Commission of Wisconsin (PSCW) | Badger Hollow and Two Creeks Solar Farms |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |
Number of solar projects in Wisconsin that WPS filed with the PSCW to acquire an interest in | solar_projects | 2 |  |  |  |  |  |  |  |  |
WPS total ownership in two solar projects (in megawatts) | MW | 200 |  |  |  |  |  |  |  |  |
WPS share of cost for certain solar projects | $ 260.0 |  |  |  |  |  |  |  |  |
WPS | Public Service Commission of Wisconsin (PSCW) | Badger Hollow Solar Farm |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |
WPS individual ownership in a solar farm (in megawatts) | MW | 100 |  |  |  |  |  |  |  |  |
WPS | Public Service Commission of Wisconsin (PSCW) | Two Creeks Solar Project |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |
WPS individual ownership in a solar farm (in megawatts) | MW | 100 |  |  |  |  |  |  |  |  |
WPS | Public Service Commission of Wisconsin (PSCW) | 2018 and 2019 rates |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |
Approved return on equity (as a percent) |  |  |  |  |  |  | 10.00% |  |  |
Authorized revenue requirement for the ReACT project |  |  |  |  |  |  | $ 275.0 |  |  |
AFUDC |  |  |  |  |  |  | 51.0 |  |  |
Estimated cost of the ReACT project, excluding AFUDC |  |  |  |  |  |  | $ 342.0 |  |  |
WPS | Public Service Commission of Wisconsin (PSCW) | 2018 and 2019 rates | Electric rates |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |
Percentage of current tax benefit from Tax Cuts and Jobs Act of 2017 to be used to reduce certain regulatory assets | 40.00% |  |  |  |  |  |  |  |  |
Percent of current tax benefit from Tax Cuts and Jobs Act of 2017 to be returned to customers via bill credits | 60.00% |  |  |  |  |  |  |  |  |
WE, WG, and WPS | Public Service Commission of Wisconsin (PSCW) | 2018 and 2019 rates |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |
Number of utilities with earnings sharing mechanism | utility |  |  |  |  |  |  | 3 |  |  |
Return on equity in excess of authorized amount (as a percent) |  |  |  |  |  |  | 0.50% |  |  |
Percentage of first 50 basis points of additional utility earnings shared with customers |  |  |  |  |  |  | 50.00% |  |  |
WE, WG, and WPS | Public Service Commission of Wisconsin (PSCW) | 2018 and 2019 rates | Natural gas rates |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |
Percent of current tax benefit from Tax Cuts and Jobs Act of 2017 to be returned to customers via bill credits | 100.00% |  |  |  |  |  |  |  |  |
PGL | Illinois Commerce Commission (ICC) |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |
Amount of rate base reduction as a result of a settlement |  |  | $ 5.4 |  |  |  |  |  |  |
Amount to be refunded to ratepayers as a result of a settlement |  |  | $ 4.7 |  |  |  |  |  |  |
Amount of assurance that PGL's QIP rider costs will be recoverable | Assurance |  |  |  |  |  |  |  | 0 | 0 |
MGU and UMERC | Michigan Public Service Commission (MPSC) |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |
Number of filings required related to the Tax Cuts and Jobs Act of 2017 | Filings |  |  | 3 |  |  |  |  |  |  |
MERC | Minnesota Public Utilities Commission (MPUC) | 2018 rates | Natural gas rates |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |
Requested rate increase |  |  |  |  |  | $ 12.6 |  |  |  |
Requested rate increase (as a percent) |  |  |  |  |  | 5.05% |  |  |  |
Requested return on equity (as a percent) |  |  |  |  |  | 10.30% |  |  |  |
Requested common equity component average (as a percent) |  |  |  |  |  | 50.90% |  |  |  |
Interim rate increase |  | $ 7.0 |  |  | $ 9.5 |  |  |  |  |
Interim rate increase, (as a percent) |  | 2.81% |  |  | 3.78% |  |  |  |  |
Interim rate reduction |  | $ 2.5 |  |  |  |  |  |  |  |
Interim rates return on equity (as a percent) |  | 9.10% |  |  |  |  |  |  |  |
Interim rates common equity component average (as a percent) |  | 50.90% |  |  |  |  |  |  |  |
Utility operations | Tax Cuts And Jobs Act Of 2017 |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |
Change in deferred taxes from tax legislation |  |  |  | $ 2,450.0 |  |  |  |  |  |

X
- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 6.I) -URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319 + Details
Name: | us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The increase (decrease) during the reporting period in the account that represents the temporary difference that results from Income or Loss that is recognized for accounting purposes but not for tax purposes and vice versa. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 + Details
Name: | us-gaap_IncreaseDecreaseInDeferredIncomeTaxes
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of cash paid for the settlement of litigation or for other legal issues during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 25 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3536-108585 + Details
Name: | us-gaap_PaymentsForLegalSettlements
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount capitalized of allowance for funds used during construction. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 835 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6501569&loc=d3e55921-110430 + Details
Name: | us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Percentage of public utility's approved return on equity. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesApprovedReturnOnEquityPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Amount of public utility's interim rate increase (decrease) allowed while waiting final decision of regulatory agency. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesInterimRateIncreaseDecreaseAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Percentage of public utility's interim rate increase (decrease) allowed while waiting final decision of regulatory agency. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesInterimRateIncreaseDecreasePercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- 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

X
- Definition Percentage of public utility's requested equity to capital, including debt and equity. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesRequestedEquityCapitalStructurePercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of public utility's requested rate increase (decrease) with regulatory agency. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesRequestedRateIncreaseDecreaseAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Percentage of public utility's requested rate increase (decrease) with regulatory agency. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesRequestedRateIncreaseDecreasePercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of public utility's requested return on equity. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesRequestedReturnOnEquityPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Actual return on equity (ROE) in excess of authorized amount, for which a percentage will be returned to customers. + References No definition available. + Details
Name: | wec_ActualROEInExcessOfAuthorizedAmount
Namespace Prefix: | wec_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- 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

X
- Definition The authorized revenue requirement for ReACT that was used to calculate the ReACT deferral. + References No definition available. + Details
Name: | wec_AuthorizedRevenueRequirementForReACT
Namespace Prefix: | wec_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The total cost of WPS's ReACT project, excluding AFUDC. + References No definition available. + Details
Name: | wec_CostOfReACTProjectExcludingAFUDC
Namespace Prefix: | wec_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Income Statement impact of flow through of repair related deferred tax liabilities. The flow through of repair related deferred tax liabilities had no impact on our statements of income. + References No definition available. + Details
Name: | wec_IncomeStatementimpactofflowthroughofrepairrelateddeferredtaxliabilities
Namespace Prefix: | wec_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Reduction to interim rates as a result of federal tax reform + References No definition available. + Details
Name: | wec_InterimRateReduction
Namespace Prefix: | wec_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of utilities that agreed to employ an earnings sharing mechanism. + References No definition available. + Details
Name: | wec_NumberOfUtilitiesWithEarningsSharingMechanism
Namespace Prefix: | wec_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the number of retail electric customers in Michigan that are served by Wisconsin Electric Power Company + References No definition available. + Details
Name: | wec_NumberofElectricCustomersServedinMichigan
Namespace Prefix: | wec_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition In May 2018 WPS filed an application with the PSCW to acquire an interest in two solar projects + References No definition available. + Details
Name: | wec_NumberofSolarProjectsinWIthatWPSFiledwiththePSCWtoAcquireanInterestIn
Namespace Prefix: | wec_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of filings required related to the Tax Cuts and Jobs Act of 2018, which will be used to describe how benefits under this Act will be refunded to customers + References No definition available. + Details
Name: | wec_NumberoffilingsrequiredrelatedtotheTaxCutsandJobsActof2018
Namespace Prefix: | wec_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of first 50 basis points of additional utility earnings that will be shared with customers. + References No definition available. + Details
Name: | wec_PercentageOfFirst50BasisPointsSharedWithCustomers
Namespace Prefix: | wec_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the percent of current 2018 and 2019 tax benefits from the Tax Cuts and Jobs Act of 2017 for our Wisconsin electric utility customers to be used to reduce certain regulatory assets + References No definition available. + Details
Name: | wec_PercentageofcurrenttaxbenefitfromTaxCutsandJobsActof2017tobeusedtoreduceregulatoryassets
Namespace Prefix: | wec_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the percent of current 2018 and 2019 tax benefits from the Tax Cuts and Jobs Act of 2017 to be returned to Wisconsin electric utility customers via bill credits + References No definition available. + Details
Name: | wec_PercentofcurrenttaxbenefitfromTaxCutsandJobsActof2017tobereturnedtocustomersviabillcredits
Namespace Prefix: | wec_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of public utility's interim equity to capital, including debt and equity, approved. + References No definition available. + Details
Name: | wec_PublicUtilitiesInterimRatesEquityCapitalStructurePercentage
Namespace Prefix: | wec_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of public utilities interim return on equity approved. + References No definition available. + Details
Name: | wec_PublicUtilitiesInterimRatesReturnonEquityPercentage
Namespace Prefix: | wec_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition WPS Total Ownership Capacity in solar projects + References No definition available. + Details
Name: | wec_WPSTotalOwnershipCapacityinBadgerHollowandTwoCreeks
Namespace Prefix: | wec_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition WPS Share of Cost for Badger Hollow and Two Creeks solar projects + References No definition available. + Details
Name: | wec_WPSTotalShareofCostofBadgerHollowandTwoCreeks
Namespace Prefix: | wec_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition WPS individual ownership in solar projects + References No definition available. + Details
Name: | wec_WPSindividualownershipinterest
Namespace Prefix: | wec_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | dei_LegalEntityAxis=wec_WisconsinElectricPowerCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAgencyAxis=wec_PublicServiceCommissionOfWisconsinPSCWMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | wec_RateCaseYearAxis=wec_Rate2018And2019Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilitiesRegulatoryProceedingAxis=wec_ElectricRateRequestMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAgencyAxis=wec_MichiganPublicServiceCommissionMPSCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=wec_WisconsinGasLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=wec_WisconsinPublicServiceCorporationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

X
- Details
Name: | dei_LegalEntityAxis=wec_WisconsinElectricPowerCompanyWisconsinGasLLCWisconsinPublicServiceCorporationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilitiesRegulatoryProceedingAxis=wec_NaturalGasRateRequestMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=wec_ThePeoplesGasLightAndCokeCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | dei_LegalEntityAxis=wec_MichiganGasUtilitiesCorporationandUpperMichiganEnergyResourcesCorporationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=wec_MinnesotaEnergyResourcesCorporationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAgencyAxis=wec_MinnesotaPublicUtilitiesCommissionMPUCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | wec_RateCaseYearAxis=wec_Rates2018Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityRegulatedOrUnregulatedStatusAxis=us-gaap_RegulatedOperationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ChangeInAccountingEstimateByTypeAxis=wec_TaxCutsAndJobsActOf2017Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |