REGULATORY ENVIRONMENT - WI 2018 AND 2019 RATES (Details) - 2018 and 2019 rates - Public Service Commission of Wisconsin (PSCW) $ in Millions	1 Months Ended	9 Months Ended
	Sep. 30, 2017 USD ($) utility	Sep. 30, 2019 USD ($)
WE
Public Utilities, General Disclosures [Line Items]
Approved return on equity (as a percent)	10.20%
Income statement impact of flow through of repair-related deferred tax liabilities		$ 0.0
WG
Public Utilities, General Disclosures [Line Items]
Approved return on equity (as a percent)	10.30%
WPS
Public Utilities, General Disclosures [Line Items]
Approved return on equity (as a percent)	10.00%
Authorized revenue requirement for the ReACT project	$ 275.0
AFUDC for the ReACT project	51.0
Cost of the ReACT project, excluding AFUDC	$ 342.0
WE, WG, and WPS
Public Utilities, General Disclosures [Line Items]
Number of utilities with earnings sharing mechanism | utility	3
Percentage of first 50 basis points of additional utility earnings shared with customers	50.00%
Return on equity in excess of authorized amount (as a percent)	0.50%