Pension and other post-retirement obligations (Tables)
 12 Months Ended
Jun. 30, 2021
Text block [abstract]  
Summary of Net Liability Recognised in Consolidated Balance Sheet
Net liability recognised in the Consolidated Balance Sheet
The net liability recognised in the Consolidated Balance Sheet is as follows:
 
    
Defined benefit pension

schemes / post-

employment obligations
    
Post-retirement medical

schemes
  
    
2021
     2020    
2021
      2020  
    
US$M
     US$M    
US$M
      US$M  
Present value of funded defined benefit obligation
   
 
377
 
     613    
 
–
 
      –  
Present value of unfunded defined benefit obligation
   
 
358
 
     354    
 
197
 
      214  
Fair value of defined benefit scheme assets
   
 
(398
) 
     (634 )   
 
–
 
      –  
    
 
 
    
 
 
    
 
 
     
 
 
  
Scheme deficit
   
 
337
 
     333    
 
197
 
      214  
    
 
 
    
 
 
    
 
 
     
 
 
  
Unrecognised surplus
   
 
–
 
     –    
 
–
 
      –  
Unrecognised past service credits
   
 
–
 
     –    
 
–
 
      –  
Adjustment for employer contributions tax
   
 
–
 
     –    
 
–
 
      –  
    
 
 
    
 
 
    
 
 
     
 
 
  
Net liability recognised in the Consolidated Balance Sheet
   
 
337
 
     333    
 
197
 
      214