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REGULATORY ENVIRONMENT (Details) $ in Millions | 1 Months Ended | 3 Months Ended | 6 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 ($) | Oct. 31, 2017 USD ($) MW | Sep. 30, 2017 USD ($) utility | Aug. 31, 2016 MW | Jun. 30, 2018 customer Assurance | Jun. 30, 2018 USD ($) customer change Assurance | Jun. 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 WI that WPS Filed with the PSCW to Acquire an Interest In | solar_projects | 2 |  |  |  |  |  |  |  |  |  |
WPS Ownership Interest in Badger Hollow and Two Creeks | MW | 100 |  |  |  |  |  |  |  |  |  |
WPS Total Ownership Capacity in Badger Hollow and Two Creeks | MW | 200 |  |  |  |  |  |  |  |  |  |
WPS Total Share of Cost of Badger Hollow and Two Creeks | $ 260.0 |  |  |  |  |  |  |  |  |  |
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% |  |  |  |  |  |  |  |  |  |
WE and WPS | Public Service Commission of Wisconsin (PSCW) | 2018 and 2019 rates | Electric rates |  |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |  |
Decrease in Regulatory Assets Related to PSCW Tax Legislation Ruling |  |  |  |  |  |  |  |  |  | $ 46.9 |
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% |  |  |  |  |  |  |  |  |
UMERC |  |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |  |
Capacity of natural gas-fired generation facility (in megawatts) | MW |  |  |  |  |  | 180 |  |  |  |  |
UMERC | Michigan Public Service Commission (MPSC) |  |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |  |
Term of electric power purchase agreement (in years) |  |  |  |  |  |  |  | 20 years |  |  |
Capacity of natural gas-fired generation facility (in megawatts) | MW |  |  |  |  |  |  |  | 180 |  |  |
Estimated cost of constructing a power plant |  |  |  |  |  | $ 266.0 |  |  |  |  |
Estimated cost of constructing a power plant, including AFUDC |  |  |  |  |  | $ 277.0 |  |  |  |  |
Portion of the power plant costs recoverable from Tilden Mining Company (as a percent) |  |  |  |  |  | 50.00% |  |  |  |  |
Portion of the power plant costs recoverable from utility customers (as a percent) |  |  |  |  |  | 50.00% |  |  |  |  |
Utility Operations | Tax Cuts And Jobs Act Of 2017 |  |  |  |  |  |  |  |  |  |  |
Regulatory environment |  |  |  |  |  |  |  |  |  |  |
Change in deferred taxes from tax legislation |  |  |  | $ 2,450.0 |  |  |  |  |  |  |

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