XML 294 R269.htm IDEA: XBRL DOCUMENT v3.21.1
Derivative financial instruments - Additional information (Details) - USD ($)
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Disclosure of derivative financial instruments [Line Items]      
Hedge instruments $ 18,439,000    
Gain/loss on hedge ineffectiveness recognised in profit or loss 4,000,000 $ (322,000,000,000) $ (1,398,000,000,000)
Gain (loss) on change in fair value of derivatives (18,439,000) (2,759,000) 31,464,000
Effect on settlement of hedging financial instruments 146,000 0 0
Sociedad Minera Cerro Verde S.A.A. [Member]      
Disclosure of derivative financial instruments [Line Items]      
Trade account receivable due from related parties 101,400,000 36,100,000  
Trade accounts receivable net   600,000  
Other reserves [member]      
Disclosure of derivative financial instruments [Line Items]      
Gain (loss) on change in fair value of derivatives $ 18,400,000 2,800,000 $ 31,500,000
Net deferred income tax asset   $ 6,464,000