XML 70 R58.htm IDEA: XBRL DOCUMENT v3.6.0.2
Acquisitions (Details) - Integrys - USD ($)
$ in Millions
1 Months Ended 12 Months Ended
Jun. 30, 2015
Dec. 31, 2016
Dec. 31, 2015
Jun. 29, 2015
PSCW Conditions of Approval - Earnings Sharing Mechanism        
Duration of earnings cap condition imposed by the PSCW (in years) 3 years      
Percentage of first 50 basis points to be shared with customers       50.00%
ROE in excess of authorized amount (as a percent)       0.50%
Severance        
Severance expense     $ 6.6  
Severance payments   $ 4.6 $ 1.2  
WEC Energy Group        
Business Acquisition [Line Items]        
Percentage of Integrys common shares acquired       100.00%
Earnings sharing mechanism        
PSCW Conditions of Approval - Earnings Sharing Mechanism        
Expense for earnings sharing mechanism   $ 21.1