XML 220 R120.htm IDEA: XBRL DOCUMENT v3.19.2
Closure and Rehabilitation Provisions - Additional Information (Detail) - Closure and rehabilitation provisions [member] - USD ($)
$ in Millions
 12 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2017
Disclosure of other provisions [line items]      
Increases to existing and new provisions associated closure and remediation costs charged to the income statement $ 318 $ 132  
Percentage of reasonably possible decrease in real discount rates 0.50%    
Increase in closure and rehabilitation provision due to reasonably possible decrease in real discount rates $ 618    
Increase in depreciation expense due to reasonably possible decrease in real discount rates $ 42    
Bottom of range [member]      
Disclosure of other provisions [line items]      
Remaining production life 1 year    
Top of range [member]      
Disclosure of other provisions [line items]      
Remaining production life 98 years    
Weighted average [member]      
Disclosure of other provisions [line items]      
Remaining production life 32 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 $ 251 $ (21) $ 33
Increase in income statement charge due to reasonably possible decrease in real discount rates 94    
Operating sites [member]      
Disclosure of other provisions [line items]      
Increase in property, plant and equipment due to reasonably possible decrease in real discount rates $ 524