Subsidiaries - Summary of Significant Subsidiaries (Parenthetical) (Detail) - BHP Iron Ore (Jimblebar) Pty Ltd [member] |
12 Months Ended | |
|---|---|---|
Jun. 30, 2021 |
Jun. 30, 2020 |
|
| Disclosure of significant subsidiaries [line items] | ||
| Effective Group interest | 92.50% | 92.50% |
| Group's interest | 85.00% | 85.00% |