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Closure and Rehabilitation Provisions - Additional Information (Detail) - Closure and rehabilitation provisions [member] - USD ($)
$ in Millions
 12 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2019
Jun. 30, 2018
Disclosure of other provisions [line items]        
Percentage of reasonably possible decrease in real discount rates   0.50%    
Increase decrease in provision due to change in discount rate   $ 675    
Increase in closure and rehabilitation provision due to reasonably possible decrease in real discount rates   $ 772    
Increase in depreciation expense due to reasonably possible decrease in real discount rates $ 35      
Decrease in net finance costs due to reasonably possible decrease in real discount rates $ 16      
Bottom of range [member]        
Disclosure of other provisions [line items]        
Remaining production life   4 years    
Top of range [member]        
Disclosure of other provisions [line items]        
Remaining production life   91 years    
Weighted average [member]        
Disclosure of other provisions [line items]        
Remaining production life   28 years    
Closed sites [member]        
Disclosure of other provisions [line items]        
Increases to existing and new provisions associated closure and remediation costs charged to the income statement   $ 669 $ 251 $ (21)
Increase decrease in provision due to change in discount rate   90    
Increase in income statement charge due to reasonably possible decrease in real discount rates   166    
Operating sites [member]        
Disclosure of other provisions [line items]        
Increase in property, plant and equipment due to reasonably possible decrease in real discount rates   $ 606