v3.25.2
Exceptional Items - Additional Information (Detail) - USD ($)
$ in Millions
 12 Months Ended
Apr. 02, 2024
Oct. 18, 2023
May 17, 2023
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2023
Disclosure of exceptional items [line items]            
Exceptional items net       $ 1,138.0 $ 5,763.0 $ 606.0
Exceptional items gross       1,234.0 6,600.0 340.0
Impairment reversals of non-current assets       90.0    
Impairment of Western Australia Nickel assets [member]            
Disclosure of exceptional items [line items]            
Exceptional items net         2,675.0  
Exceptional items gross         3,800.0  
Chilean tax reform [member]            
Disclosure of exceptional items [line items]            
Exceptional items net           283.0
Tax rate royalty on revenue     1.00%      
Tax Rate Effect Of Revenues Exempt From Taxation     46.50%      
Deferred tax position remeasured           283.0
Chilean tax reform [member] | Bottom of range [member]            
Disclosure of exceptional items [line items]            
Tax rate royalty on margin     8.00%      
Chilean tax reform [member] | Top of range [member]            
Disclosure of exceptional items [line items]            
Tax rate royalty on margin     26.00%      
Samarco dam failure [member]            
Disclosure of exceptional items [line items]            
Exceptional items net       914.0 3,762.0 323.0
Exceptional items gross       914.0 3,677.0 $ 340.0
Western Australia Nickel (WAN) temporary suspension [member]            
Disclosure of exceptional items [line items]            
Exceptional items net       224.0    
Exceptional items gross       320.0    
Employee redundancies inventory write off and other suspension costs       410.0    
Impairment reversals of non-current assets       90.0    
Blackwater and Daunia gain on divestment [member]            
Disclosure of exceptional items [line items]            
Exceptional items net         (674.0)  
Exceptional items gross         (877.0)  
Cash flows from losing control of subsidiaries or other businesses $ 2,000.0          
Proceeds from divestiture of interest in a subsidiary towards preliminary completion adjustment 44.1          
Deferred consideration $ 1,100.0     280.0 495.0  
Proportion of ownership interest in joint venture 50.00%          
Bma percentage basis 100.00%          
Deposit on signing of the asset sale agreement   $ 100.0        
Deferred consideration term 3 years          
Price linked earnout amount receivable term 3 years          
Price linked earnout subject to cap value $ 350.0          
Average realized pricing exeeding agreed thresholds term 3 years          
Portion of consideration paid (received) consisting of cash and cash equivalents $ 4,100.0       $ 1,072.0  
Deferred and contingent consideration received       $ 500.0    
Blackwater and Daunia gain on divestment [member] | Top of range [member]            
Disclosure of exceptional items [line items]            
Deferred Price linked earnout consideration receivable on divestiture of interest in a subsidiary $ 900.0