Significant Events - Summary of Financial Impacts of Samarco Dam Failure (Parenthetical) (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Jun. 30, 2021 |
Jun. 30, 2020 |
Jun. 30, 2019 |
|
| Disclosure of exceptional items [line items] | |||
| Funding provided during the period | $ (219) | ||
| Samarco Germano Dam Decommissioning one [Member] | |||
| Disclosure of exceptional items [line items] | |||
| Change in estimate | (6) | $ 37 | $ 263 |
| Exchange translation | 21 | (83) | 0 |
| Utilisation | (8) | (4) | 0 |
| Samarco dam failure one [Member] | |||
| Disclosure of exceptional items [line items] | |||
| Change in estimate | 842 | 916 | 579 |
| Exchange translation | 158 | (457) | 7 |
| Funding provided during the period | (111) | (95) | (96) |
| Utilisation | $ (351) | $ (365) | $ (328) |