v3.26.1
Property, plant and equipment (Schedule of detailed information about property, plant and equipment) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Disclosure of detailed information about property, plant and equipment [line items]    
Balance, beginning of year $ 4,181.4  
Decommissioning and restoration (0.2) $ (4.7)
Derecognition of assets (2.8) 0.0
Impairment reversal 322.3  
Balance, end of year 4,693.9 4,181.4
Cost [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance, beginning of year 7,146.0 6,901.9
Additions 400.3 325.7
Capitalized stripping and development 182.2 160.5
Decommissioning and restoration (0.2) (4.7)
Capitalized accretion and depreciation 0.0 0.6
Transfers and other movements 0.0 0.0
Disposals (20.1) (42.0)
Impairment reversal 322.3  
Effects of movement in exchange rates 121.5 (196.0)
Balance, end of year 8,152.0 7,146.0
Accumulated depreciation [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance, beginning of year (2,964.6) (2,585.9)
Depreciation for the year (462.1) (456.8)
Disposals 14.0 10.4
Effects of movement in exchange rates (45.4) 67.7
Balance, end of year (3,458.1) (2,964.6)
Exploration and evaluation assets [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance, beginning of year 103.4  
Balance, end of year 108.9 103.4
Exploration and evaluation assets [Member] | Cost [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance, beginning of year 103.4 96.9
Additions 5.2 8.6
Capitalized stripping and development 0.0 0.0
Decommissioning and restoration 0.0 0.0
Capitalized accretion and depreciation 0.0 0.0
Transfers and other movements 0.0 0.0
Disposals (1.1) 0.0
Impairment reversal 0.0  
Effects of movement in exchange rates 1.4 (2.1)
Balance, end of year 108.9 103.4
Exploration and evaluation assets [Member] | Accumulated depreciation [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance, beginning of year 0.0 0.0
Depreciation for the year 0.0 0.0
Disposals 0.0 0.0
Effects of movement in exchange rates 0.0 0.0
Balance, end of year 0.0 0.0
Capital works in progress [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance, beginning of year 863.9  
Balance, end of year 1,359.8 863.9
Capital works in progress [Member] | Cost [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance, beginning of year 863.9 804.6
Additions 285.6 239.4
Capitalized stripping and development 0.0 0.0
Decommissioning and restoration 0.3 0.0
Capitalized accretion and depreciation 2.0 2.2
Transfers and other movements (117.5) (168.4)
Disposals (0.6) (11.9)
Impairment reversal 322.3  
Effects of movement in exchange rates 3.8 (2.0)
Balance, end of year 1,359.8 863.9
Capital works in progress [Member] | Accumulated depreciation [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance, beginning of year 0.0 0.0
Depreciation for the year 0.0 0.0
Disposals 0.0 0.0
Effects of movement in exchange rates 0.0 0.0
Balance, end of year 0.0 0.0
Mining properties [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance, beginning of year 1,303.9  
Balance, end of year 1,319.6 1,303.9
Mining properties [Member] | Cost [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance, beginning of year 2,578.3 2,482.7
Additions 23.4 14.5
Capitalized stripping and development 182.2 160.5
Decommissioning and restoration (0.9) 13.5
Capitalized accretion and depreciation 0.0 0.0
Transfers and other movements 3.7 (3.7)
Disposals 0.0 0.0
Impairment reversal 0.0  
Effects of movement in exchange rates 55.9 (89.2)
Balance, end of year 2,842.6 2,578.3
Mining properties [Member] | Accumulated depreciation [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance, beginning of year (1,274.4) (1,093.9)
Depreciation for the year (225.2) (216.0)
Disposals 0.0 0.0
Effects of movement in exchange rates (23.4) 35.5
Balance, end of year (1,523.0) (1,274.4)
Plant and equipment [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance, beginning of year 1,820.7  
Balance, end of year 1,823.5 1,820.7
Plant and equipment [Member] | Cost [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance, beginning of year 3,345.3 3,274.2
Additions 68.4 37.7
Capitalized stripping and development 0.0 0.0
Decommissioning and restoration 0.4 (18.2)
Capitalized accretion and depreciation 0.0 0.0
Transfers and other movements 108.2 174.6
Disposals (13.4) (23.7)
Impairment reversal 0.0  
Effects of movement in exchange rates 58.3 (99.3)
Balance, end of year 3,567.2 3,345.3
Plant and equipment [Member] | Accumulated depreciation [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance, beginning of year (1,524.6) (1,348.9)
Depreciation for the year (208.0) (216.8)
Disposals 10.0 9.4
Effects of movement in exchange rates (21.1) 31.7
Balance, end of year (1,743.7) (1,524.6)
Plant and equipment - ROU assets [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance, beginning of year 89.5  
Balance, end of year 82.1 89.5
Plant and equipment - ROU assets [Member] | Cost [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance, beginning of year 255.1 243.5
Additions 17.7 25.5
Capitalized stripping and development 0.0 0.0
Decommissioning and restoration 0.0 0.0
Capitalized accretion and depreciation (2.0) (1.6)
Transfers and other movements 5.6 (2.5)
Disposals (5.0) (6.4)
Impairment reversal 0.0  
Effects of movement in exchange rates 2.1 (3.4)
Balance, end of year 273.5 255.1
Plant and equipment - ROU assets [Member] | Accumulated depreciation [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance, beginning of year (165.6) (143.1)
Depreciation for the year (28.9) (24.0)
Disposals 4.0 1.0
Effects of movement in exchange rates (0.9) 0.5
Balance, end of year $ (191.4) $ (165.6)