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.

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=118932676&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	Feb. 28, 2018 Filings	Dec. 31, 2017 USD ($)	Dec. 31, 2019 customer
Public Utilities, General Disclosures [Line Items]
Estimated tax benefit related to the remeasurement of deferred income taxes from tax legislation			$ 2,657
MPSC \| WE
Public Utilities, General Disclosures [Line Items]
Number of Electric Customers Served in Michigan \| customer				1
MPSC \| MGU
Public Utilities, General Disclosures [Line Items]
Number of filings required related to the Tax Cuts and Jobs Act of 2018 \| Filings		3
Tax Cuts and Jobs Act of 2017 \| Utility operations
Public Utilities, General Disclosures [Line Items]
Estimated tax benefit related to the remeasurement of deferred income taxes from tax legislation			$ 2,529
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%