v3.25.2
Climate change - Additional Information (Detail) - USD ($)
$ in Millions
 12 Months Ended 120 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2030
Jun. 30, 2023
Disclosure Of Climate Change [Line Items]        
Property, plant and equipment $ 76,457 $ 71,629   $ 71,818
Carbon credits surrender obligation 17 1    
Lease liabilities 2,953 3,116    
Fair value of financial derivatives 1,683 1,610    
Expenditure to support value chain 60      
Increase decrease in rehabilitation provision due to change in the life of mines 40      
Asset Impairment Loss 261 3,890    
Carbon credits available for trading 0 0    
Carbon credits held for surrender 19 23    
Prepayment Of Carbon Credit 32      
Ghg emission obligation 8 17    
Estimate Expenses For Decarbonisation 500      
Carbon credits voluntary surrender 0      
Power purchase contract agreements [member]        
Disclosure Of Climate Change [Line Items]        
Lease liabilities 43 44    
Fair value of financial derivatives 37 $ 92    
Operating segments [member] | Coal [member]        
Disclosure Of Climate Change [Line Items]        
Asset Impairment Loss 2,000      
Operating segments [member] | Coal [member] | New South Wales Energy Coal [member]        
Disclosure Of Climate Change [Line Items]        
Property, plant and equipment 900      
Provisions ​for equitable transition $ 0      
Scenario Forecast [member]        
Disclosure Of Climate Change [Line Items]        
Decrease In Percentage Of Reduction Of Operational GHG Emissions     30.00%  
Bottom of range [member] | Operating segments [member]        
Disclosure Of Climate Change [Line Items]        
Discount rate used in current estimate of value in use 7.00% 7.00%    
Top of range [member] | Operating segments [member]        
Disclosure Of Climate Change [Line Items]        
Discount rate used in current estimate of value in use 9.50% 9.50%