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Provisions - Schedule of Assumption in Provision Calculation (Detail)
Dec. 31, 2022
Dec. 31, 2021
South Africa    
Disclosure of Provisions [line items]    
Discount rate 11.40% 10.60%
South Africa | Inflation rate Year 1    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 5.30% 4.50%
South Africa | Inflation rate Year 2    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 4.70% 4.50%
South Africa | Inflation rate Year 3    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 4.60% 4.50%
South Africa | Inflation rate Year 4 onwards    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 4.60% 4.50%
Ghana | Inflation rate Year 1    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 3.40% 2.40%
Ghana | Inflation rate Year 2    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 2.60% 2.40%
Ghana | Inflation rate Year 3    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 2.40% 2.40%
Ghana | Inflation rate Year 4 onwards    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 2.40% 2.40%
Australia    
Disclosure of Provisions [line items]    
Discount rate   2.40%
Australia | Inflation rate Year 1    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 4.80% 2.40%
Australia | Inflation rate Year 2    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 2.90% 2.40%
Australia | Inflation rate Year 3    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 2.70% 2.40%
Australia | Inflation rate Year 4 onwards    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 2.50% 2.40%
Peru    
Disclosure of Provisions [line items]    
Discount rate 5.40% 2.80%
Peru | Inflation rate Year 1    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 3.40% 2.40%
Peru | Inflation rate Year 2    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 2.60% 2.40%
Peru | Inflation rate Year 3    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 2.40% 2.40%
Peru | Inflation rate Year 4 onwards    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 2.40% 2.40%
Chile    
Disclosure of Provisions [line items]    
Discount rate 4.70% 2.40%
Chile | Inflation rate Year 1    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 3.40% 2.40%
Chile | Inflation rate Year 2    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 2.60% 2.40%
Chile | Inflation rate Year 3    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 2.40% 2.40%
Chile | Inflation rate Year 4 onwards    
Disclosure of Provisions [line items]    
Inflation rate Year 4 onwards 2.40% 2.40%
Bottom of range | Ghana    
Disclosure of Provisions [line items]    
Discount rate 15.00% 6.60%
Bottom of range | Australia    
Disclosure of Provisions [line items]    
Discount rate 4.00%  
Top of range | Ghana    
Disclosure of Provisions [line items]    
Discount rate 15.20% 7.20%
Top of range | Australia    
Disclosure of Provisions [line items]    
Discount rate 4.30%