v3.25.4
Financial instruments - Financial assets and liabilities (Details) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Disclosure of detailed information about financial instruments [line items]    
Financial assets $ 469 $ 948
Financial assets, fair value 469 948
Financial liabilities 890 812
Financial liabilities, fair value 890 812
Payables and accrued liabilities    
Disclosure of detailed information about financial instruments [line items]    
Financial liabilities 580 600
Financial liabilities, fair value 580 600
Long-Term Debt    
Disclosure of detailed information about financial instruments [line items]    
Financial liabilities 300 200
Financial liabilities, fair value 300 200
Electricity Swaps    
Disclosure of detailed information about financial instruments [line items]    
Financial assets 24  
Financial assets, fair value 24  
Financial liabilities 10 12
Financial liabilities, fair value 10 12
Financial liabilities at fair value through profit or loss, category    
Disclosure of detailed information about financial instruments [line items]    
Financial liabilities 10 12
Financial liabilities at fair value through profit or loss, category | Payables and accrued liabilities    
Disclosure of detailed information about financial instruments [line items]    
Financial liabilities 0  
Financial liabilities at fair value through profit or loss, category | Electricity Swaps    
Disclosure of detailed information about financial instruments [line items]    
Financial assets 24  
Financial liabilities 10 12
Financial Liabilities, Other, Category    
Disclosure of detailed information about financial instruments [line items]    
Financial liabilities 880 800
Financial Liabilities, Other, Category | Payables and accrued liabilities    
Disclosure of detailed information about financial instruments [line items]    
Financial liabilities 580 600
Financial Liabilities, Other, Category | Long-Term Debt    
Disclosure of detailed information about financial instruments [line items]    
Financial liabilities 300 200
Cash And Short Term Investments    
Disclosure of detailed information about financial instruments [line items]    
Financial assets 202 641
Financial assets, fair value 202 641
Trade receivables    
Disclosure of detailed information about financial instruments [line items]    
Financial assets 244 292
Financial assets, fair value 244 292
Interest rate swaps    
Disclosure of detailed information about financial instruments [line items]    
Financial assets 0 2
Financial assets, fair value 0 2
Electricity Swaps    
Disclosure of detailed information about financial instruments [line items]    
Financial assets   13
Financial assets, fair value   13
Financial assets at amortised cost, category    
Disclosure of detailed information about financial instruments [line items]    
Financial assets 445 933
Financial liabilities 0 0
Financial assets at amortised cost, category | Cash And Short Term Investments    
Disclosure of detailed information about financial instruments [line items]    
Financial assets 202 641
Financial assets at amortised cost, category | Trade receivables    
Disclosure of detailed information about financial instruments [line items]    
Financial assets 244 292
Financial assets at fair value through profit or loss, category    
Disclosure of detailed information about financial instruments [line items]    
Financial assets 24 15
Financial assets at fair value through profit or loss, category | Interest rate swaps    
Disclosure of detailed information about financial instruments [line items]    
Financial assets $ 0 2
Financial assets at fair value through profit or loss, category | Electricity Swaps    
Disclosure of detailed information about financial instruments [line items]    
Financial assets   $ 13