v3.26.1
RELATED PARTY TRANSACTIONS: (Details)
$ in Millions
 6 Months Ended 12 Months Ended
Jun. 30, 2026
USD ($)
Jun. 30, 2025
USD ($)
Dec. 31, 2020
MWh
Dec. 31, 2012
item
MW
Dec. 31, 2025
USD ($)
Dec. 31, 2014
item
RELATED PARTY TRANSACTIONS:            
Related parties receivable current: $ 10.9       $ 16.2  
Affiliates            
RELATED PARTY TRANSACTIONS:            
Related parties receivable current: 10.9       16.2  
Related parties payable: 122.5       138.4  
Total purchases 171.9 $ 225.0        
Total sales $ 1.8 1.5        
Affiliates | Compaia Minera Coimolache S.A. ("Coimolache")            
RELATED PARTY TRANSACTIONS:            
Ownership percentage (Equity method investment) 44.20%          
Affiliates | Apu Coropuna S.R.L.            
RELATED PARTY TRANSACTIONS:            
Ownership percentage (Equity method investment) 30.00%          
Affiliates | Minimum            
RELATED PARTY TRANSACTIONS:            
Aggregate consideration of Material Affiliate Transaction to be be authorized by the General Counsel and CFO $ 8.0          
Affiliates | Maximum            
RELATED PARTY TRANSACTIONS:            
Aggregate consideration of Material Affiliate Transaction to be be authorized by the General Counsel and CFO 10.0          
Grupo Mexico and affiliates | Affiliates            
RELATED PARTY TRANSACTIONS:            
Total sales 15.5 59.3        
Asarco LLC ("Asarco") | Affiliates            
RELATED PARTY TRANSACTIONS:            
Related parties receivable current: 7.6       7.1  
Related parties payable: 38.9       61.1  
Total purchases 3.0 28.0        
Total sales 24.6 27.4        
AMMINCO Apoyo Administrativo, S.A. de C.V. ("AMMINCO") | Affiliates            
RELATED PARTY TRANSACTIONS:            
Related parties payable: 10.1       15.9  
Total purchases 6.0 5.0        
Total sales 0.1          
Eolica El Retiro, S.A.P.I. de C.V.            
RELATED PARTY TRANSACTIONS:            
Number of wind turbines | item           37
Eolica El Retiro, S.A.P.I. de C.V. | Affiliates            
RELATED PARTY TRANSACTIONS:            
Related parties payable: 0.5       0.3  
Total purchases $ 0.3 $ 1.0        
Percentage of supply to third-party energy users 16.60% 11.70%        
Ferrocarril Mexicano, S.A. de C.V. | Affiliates            
RELATED PARTY TRANSACTIONS:            
Related parties payable: $ 4.4       4.0  
Total purchases 23.6 $ 21.3        
Grupo Mexico and affiliates | Affiliates            
RELATED PARTY TRANSACTIONS:            
Total purchases 1.8 1.7        
Grupo Mexico Servicios | Affiliates            
RELATED PARTY TRANSACTIONS:            
Related parties payable: 2.3       3.3  
Total purchases 10.1 10.1        
Mexico Generadora de Energia S. de R.L. ("MGE") | Mexico            
RELATED PARTY TRANSACTIONS:            
Number of natural gas-fired combined cycle power generating units | item       2    
Mexico Generadora de Energia S. de R.L. ("MGE") | Affiliates            
RELATED PARTY TRANSACTIONS:            
Related parties receivable current: 1.1       7.6  
Related parties payable: 44.7       30.2  
Total purchases 80.9 109.8        
Total sales (9.3) $ 31.9        
Amount of net credit from the sale of natural gas $ 9.3          
Mexico Generadora de Energia S. de R.L. ("MGE") | Affiliates | Mexico            
RELATED PARTY TRANSACTIONS:            
Net total capacity (in megawatts) | MW       516.2    
Percentage of supply to third-party energy users 18.30% 0.30%        
Mexico Compania Constructora S.A de C.V. | Affiliates            
RELATED PARTY TRANSACTIONS:            
Related parties payable: $ 9.7       12.4  
Total purchases 16.1 $ 24.8        
Parque Eolico de Fenicias, S. de R.L. de C.V. | Affiliates            
RELATED PARTY TRANSACTIONS:            
Related parties payable: 8.4       7.5  
Total purchases $ 22.7 $ 20.3        
Percentage of supply to third-party energy users 98.00% 85.50%        
Purchase agreement, contracted power capacity (in megawatts per year) | MWh     611,400      
Term of power purchase agreement related to sale of power plant     20 years      
Grupo Mexico Servicios de Ingenieria, S.A. de C.V. | Affiliates            
RELATED PARTY TRANSACTIONS:            
Related parties payable: $ 1.4       2.3  
Total purchases 9.3 $ 4.7        
AMMINCO, Ferrocarril Mexicano, S.A. de C.V. & Mexico Compania Constructora S.A de C.V. | Affiliates | Maximum            
RELATED PARTY TRANSACTIONS:            
Related parties receivable current: 0.1       0.1  
AMMINCO & Ferrocarril Mexicano, S.A. de C.V. | Affiliates | Maximum            
RELATED PARTY TRANSACTIONS:            
Threshold revenue from related parties 0.1 0.1        
Boutique Bowling de Mexico, S.A. de C.V. | Affiliates            
RELATED PARTY TRANSACTIONS:            
Related parties payable: 1.1       0.8  
Total purchases 0.3 0.3        
Total sales 0.1 0.1        
Empresarios Industriales de Mexico, S.A. de C.V | Affiliates            
RELATED PARTY TRANSACTIONS:            
Related parties receivable current: 1.9       1.5  
Total sales 0.4 0.2        
Mextransport | Affiliates            
RELATED PARTY TRANSACTIONS:            
Related parties receivable current: 0.3          
Related parties payable: 0.5       0.4  
Total purchases 1.3 1.2        
Total sales 1.3 1.1        
Operadora de Cinemas S.A. de C.V. | Affiliates            
RELATED PARTY TRANSACTIONS:            
Related parties receivable current: 0.1       0.1  
Related parties payable: 0.5       $ 0.3  
Total purchases 0.2 0.2        
Total sales $ 0.1 $ 0.1