v3.26.3
LONG-TERM DEBT - ISSUANCES AND REDEMPTIONS (Details) - USD ($)
$ in Millions
1 Months Ended 9 Months Ended
Oct. 31, 2026
Sep. 30, 2026
Aug. 31, 2026
Jun. 30, 2026
Mar. 31, 2026
Feb. 28, 2026
Jan. 31, 2026
Sep. 30, 2026
Sep. 30, 2025
Debt Instrument [Line Items]                  
Repayments of Long-term Debt               $ 1,558.5 $ 1,285.9
PGL | Collateralized First Mortgage Bonds                  
Debt Instrument [Line Items]                  
Secured Debt         $ 100.0        
5.65% $300M WE Debentures due 03/15/2056 | WE                  
Debt Instrument [Line Items]                  
Interest rate on long-term debt         5.65%        
Proceeds from issuance of debt         $ 300.0        
4.65% $400M WE Debentures due 06/15/2031 | WE                  
Debt Instrument [Line Items]                  
Interest rate on long-term debt       4.65%          
Proceeds from issuance of debt       $ 400.0          
5.10% $400M WE Debentures due 06/15/2036 | WE                  
Debt Instrument [Line Items]                  
Interest rate on long-term debt       5.10%          
Proceeds from issuance of debt     $ 300.0 $ 400.0          
WPS 4.25% $300M Senior Notes due January 15, 2031 | WPS                  
Debt Instrument [Line Items]                  
Interest rate on long-term debt             4.25%    
Proceeds from issuance of debt             $ 300.0    
WPS 6.05% $300M Senior Notes due August 15, 2056 | WPS                  
Debt Instrument [Line Items]                  
Interest rate on long-term debt     6.05%            
Proceeds from issuance of debt     $ 300.0            
WG 5.60% $50M Debentures due November 1, 2031 | WG | Subsequent event                  
Debt Instrument [Line Items]                  
Interest rate on long-term debt 5.60%                
Proceeds from issuance of debt $ 50.0                
WG 5.90% $50M Debentures due November 1, 2036 | WG | Subsequent event                  
Debt Instrument [Line Items]                  
Interest rate on long-term debt 5.90%                
Proceeds from issuance of debt $ 50.0                
First and Refunding Mortgage Bonds, Series VV | PGL | Collateralized First Mortgage Bonds                  
Debt Instrument [Line Items]                  
Interest rate on long-term debt         3.90%        
Secured Debt           $ 50.0      
Repayments of Long-term Debt         $ 50.0        
First and Refunding Mortgage Bonds, Series ZZ | PGL | Collateralized First Mortgage Bonds                  
Debt Instrument [Line Items]                  
Interest rate on long-term debt         4.00%        
Secured Debt           $ 50.0      
Repayments of Long-term Debt         $ 50.0        
WEC Energy Group | WEC 4.75% Senior Notes $1000M due January 9, 2026                  
Debt Instrument [Line Items]                  
Repayment of long-term debt             $ 1,000.0    
Interest rate on long-term debt             4.75%    
WEC Energy Group | WEC 4.75% Senior Notes $400M due January 15, 2028                  
Debt Instrument [Line Items]                  
Interest rate on long-term debt           4.75%      
Proceeds from issuance of debt           $ 400.0      
WEC Energy Group | WEC 5.60% Senior Notes $350M due September 12, 2026                  
Debt Instrument [Line Items]                  
Repayment of long-term debt   $ 350.0              
Interest rate on long-term debt   5.60%           5.60%