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Impairment of Investments and Assets - Summary of Impairment of Investments and Assets (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Disclosures of impairment of investments and assets [line items]      
Investments $ 0.0 $ (113.6) $ (30.8)
Property, plant and equipment (156.4) (391.4) (11.6)
Impairment of investments and assets (156.4) (505.0) (42.4)
Total equity accounted investees $ 548.6 84.9  
Lepanto Consolidated Mining Company      
Disclosures of impairment of investments and assets [line items]      
Interest in subsidiary 60.00%    
Far Southeast Gold Resources Incorporated ("FSE")      
Disclosures of impairment of investments and assets [line items]      
Total equity accounted investees   0.0  
Peru cash-generating unit      
Disclosures of impairment of investments and assets [line items]      
Property, plant and equipment $ (156.2) $ (63.1) $ 0.0
Discount rate applied to cash flow projections   8.10% 4.80%
Recoverable amount of asset or cash-generating unit 418.8 $ 477.1  
Tarkwa cash-generating unit      
Disclosures of impairment of investments and assets [line items]      
Property, plant and equipment 0.0 $ (325.2) $ 0.0
Discount rate applied to cash flow projections   15.90% 8.30%
Recoverable amount of asset or cash-generating unit   $ 812.4  
Impairment of property, plant and equipment - other      
Disclosures of impairment of investments and assets [line items]      
Property, plant and equipment (0.2) (3.1) $ (11.6)
Capitalised exploration costs      
Disclosures of impairment of investments and assets [line items]      
Property, plant and equipment (0.1) 0.0 (10.0)
Redundant assets in Peru      
Disclosures of impairment of investments and assets [line items]      
Property, plant and equipment (0.1) (2.5) (1.6)
Redundant Assets In Chile      
Disclosures of impairment of investments and assets [line items]      
Property, plant and equipment 0.0 (0.6) 0.0
Far Southeast Gold Resources Incorporated (FSE)      
Disclosures of impairment of investments and assets [line items]      
Investments $ 0.0 $ (113.6) $ (30.8)
Far Southeast Gold Resources Incorporated (FSE) | Lepanto Consolidated Mining Company      
Disclosures of impairment of investments and assets [line items]      
Interest in subsidiary     60.00%