v3.26.1
Financial instruments - Summary of changes in fair value of Level 3 financial assets and financial liabilities (Detail) - USD ($)
$ in Millions
 6 Months Ended 12 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Jun. 30, 2025
Disclosure of detailed information about financial instruments [line items]      
Cash and cash equivalents $ 8,913 $ 8,872 $ 9,015
Financial assets measured at fair value through other comprehensive income, category      
Disclosure of detailed information about financial instruments [line items]      
Equity shares and quoted funds 186 240  
Fair value      
Disclosure of detailed information about financial instruments [line items]      
Cash and cash equivalents 8,913 8,872  
Equity shares and quoted funds 257 318  
Level 3      
Disclosure of detailed information about financial instruments [line items]      
Opening balance 172 216  
Currency translation adjustments 7 16  
Total realised gains/(losses) included in net operating costs (24) 31  
Total unrealised gains included in net operating costs 61 136  
Total unrealised gains/(losses) transferred into other comprehensive income through cash flow hedges 154 (105)  
Additions/acquisitions of financial assets and liabilities 2 85  
Disposals/maturity of financial assets and liabilities 18 (207)  
Closing balance 390 172  
Net gains included in the income statement for assets and liabilities held at period end 34 113  
Level 3 | Royalty Receivables | Forward Commodity Price And Mine Production, Measurement Input | Discounted cash flows      
Disclosure of detailed information about financial instruments [line items]      
Financial assets, at fair value 266 275  
Level 3 | Fair value      
Disclosure of detailed information about financial instruments [line items]      
Cash and cash equivalents 0 0  
Equity shares and quoted funds 137 139  
Level 1 | Fair value      
Disclosure of detailed information about financial instruments [line items]      
Cash and cash equivalents 2,788 3,725  
Equity shares and quoted funds 120 179  
Level 2 | Provisionally Priced Receivables | Applicable Forward Quoted Metal Prices, Measurement Input | Closely Related Listed Product      
Disclosure of detailed information about financial instruments [line items]      
Financial assets, at fair value 938 1,431  
Level 2 | Fair value      
Disclosure of detailed information about financial instruments [line items]      
Cash and cash equivalents 0 0  
Equity shares and quoted funds $ 0 $ 0