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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=121586364&loc=d3e3602-108585

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Regulatory Environment - Tax Cuts and Jobs Act of 2017 (Details) $ in Millions	1 Months Ended
	May 31, 2018 customer	Feb. 28, 2018 Filings	Dec. 31, 2017 USD ($)
MPSC
Public Utilities, General Disclosures [Line Items]
Number of filings required related to the Tax Cuts and Jobs Act of 2018 \| Filings		3
MPSC \| WE
Public Utilities, General Disclosures [Line Items]
Number of Electric Customers Served in Michigan \| customer	1
2018 and 2019 rates \| Electric rates \| Public Service Commission of Wisconsin (PSCW) \| WE
Public Utilities, General Disclosures [Line Items]
Percentage of current tax benefit from Tax Cuts and Jobs Act of 2017 to be used to reduce 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%
2018 and 2019 rates \| Electric rates \| Public Service Commission of Wisconsin (PSCW) \| WPS
Public Utilities, General Disclosures [Line Items]
Percentage of current tax benefit from Tax Cuts and Jobs Act of 2017 to be used to reduce 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%
2018 and 2019 rates \| Natural gas rates \| Public Service Commission of Wisconsin (PSCW) \| WE, WG, and WPS
Public Utilities, General Disclosures [Line Items]
Percent of current tax benefit from Tax Cuts and Jobs Act of 2017 to be returned to customers via bill credits	100.00%
Tax Cuts and Jobs Act of 2017 \| Regulated operations
Public Utilities, General Disclosures [Line Items]
Estimated tax benefit related to the remeasurement of deferred income taxes from tax legislation \| $			$ 2,529