v3.25.2
Financial Risk Management - Summary of Carrying Amounts of Group's Notes and Debentures by Currency and Derivatives Which Hedge (Detail) - USD ($)
$ in Millions
 12 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2023
Disclosure of detailed information about hedged items [line items]      
Carrying amount of notes and debentures $ 18,663 $ 14,932  
De-designated hedges 186 220  
Recognised in cash flow hedging reserve 16 (27) $ (10)
Recognised in cost of hedging reserve (4) 7 1
Recognised in the income statement (134) (70)  
Accrued and other cash flows (217) (177)  
Total derivatives fair value 595 1,395  
Hedged value of loans, notes and debentures 19,779 16,824  
Reserve of cash flow hedges gross [member]      
Disclosure of detailed information about hedged items [line items]      
Recognised in cash flow hedging reserve 22 (40) (15)
Cost of hedging reserve gross [member]      
Disclosure of detailed information about hedged items [line items]      
Recognised in cost of hedging reserve (6) 10 $ 1
Currency risk [member]      
Disclosure of detailed information about hedged items [line items]      
Risk 373 888  
Interest rate risk [member]      
Disclosure of detailed information about hedged items [line items]      
Risk 557 784  
USD [member]      
Disclosure of detailed information about hedged items [line items]      
Carrying amount of notes and debentures 15,120 10,928  
De-designated hedges 49 52  
Recognised in the income statement (19) 0  
Accrued and other cash flows (51) 6  
Total derivatives fair value 179 452  
Hedged value of loans, notes and debentures 15,418 11,426  
USD [member] | Reserve of cash flow hedges gross [member]      
Disclosure of detailed information about hedged items [line items]      
Recognised in cash flow hedging reserve 0 0  
USD [member] | Cost of hedging reserve gross [member]      
Disclosure of detailed information about hedged items [line items]      
Recognised in cost of hedging reserve 0 0  
USD [member] | Currency risk [member]      
Disclosure of detailed information about hedged items [line items]      
Risk 0 0  
USD [member] | Interest rate risk [member]      
Disclosure of detailed information about hedged items [line items]      
Risk 249 446  
GBP [member]      
Disclosure of detailed information about hedged items [line items]      
Carrying amount of notes and debentures 1,062 1,595  
De-designated hedges 40 43  
Recognised in the income statement (64) (72)  
Accrued and other cash flows 37 30  
Total derivatives fair value 468 673  
Hedged value of loans, notes and debentures 1,611 2,363  
GBP [member] | Reserve of cash flow hedges gross [member]      
Disclosure of detailed information about hedged items [line items]      
Recognised in cash flow hedging reserve (19) (13)  
GBP [member] | Cost of hedging reserve gross [member]      
Disclosure of detailed information about hedged items [line items]      
Recognised in cost of hedging reserve 5 3  
GBP [member] | Currency risk [member]      
Disclosure of detailed information about hedged items [line items]      
Risk 251 521  
GBP [member] | Interest rate risk [member]      
Disclosure of detailed information about hedged items [line items]      
Risk 258 204  
EUR [member]      
Disclosure of detailed information about hedged items [line items]      
Carrying amount of notes and debentures 2,481 2,409  
De-designated hedges 97 125  
Recognised in the income statement (51) 2  
Accrued and other cash flows (203) (213)  
Total derivatives fair value (52) 270  
Hedged value of loans, notes and debentures 2,750 3,035  
EUR [member] | Reserve of cash flow hedges gross [member]      
Disclosure of detailed information about hedged items [line items]      
Recognised in cash flow hedging reserve 41 (27)  
EUR [member] | Cost of hedging reserve gross [member]      
Disclosure of detailed information about hedged items [line items]      
Recognised in cost of hedging reserve (11) 7  
EUR [member] | Currency risk [member]      
Disclosure of detailed information about hedged items [line items]      
Risk 122 367  
EUR [member] | Interest rate risk [member]      
Disclosure of detailed information about hedged items [line items]      
Risk $ 50 $ 134