Changes in the Standardised Measure (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Jun. 30, 2021 |
Jun. 30, 2020 |
Jun. 30, 2019 |
|
| Extractive Industries [Abstract] | |||
| Standardised measure at the beginning of the year | $ 5,058 | $ 9,152 | $ 10,240 |
| Revisions: | |||
| Prices, net of production costs | (175) | (5,633) | 3,821 |
| Changes in future development costs | (238) | 330 | (228) |
| Revisions of reserves quantity estimates | (107) | (229) | 1,268 |
| Accretion of discount | 678 | 1,313 | 1,178 |
| Changes in production timing and other | 360 | (310) | (618) |
| Revisions | 5,576 | 4,623 | 15,661 |
| Sales of oil and gas, net of production costs | (2,901) | (2,980) | (5,029) |
| Acquisitions of reserves-in-place | 462 | ||
| Sales of reserves-in-place | 44 | (1,489) | |
| Previously estimated development costs incurred | 1,075 | 1,005 | 545 |
| Extensions, discoveries, and improved recoveries, net of future costs | 17 | 145 | (33) |
| Changes in future income taxes | 578 | 2,265 | (503) |
| Standardised measure at the end of the year | $ 4,851 | $ 5,058 | $ 9,152 |