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Number of Crude Oil and Natural Gas Wells Drilled and Completed (Parenthetical) (Detail) - Wells | 12 Months Ended
--- | ---
Jun. 30, 2019 | Jun. 30, 2018 | Jun. 30, 2017
Disclosure of net productive wells and dry wells drilled [line items] |  |  |
Net development wells, Productive | 34 | 85 | 81
Net development wells, Dry |  | 1 |
Net exploratory wells | 7 | 2 | 5
United States [member] |  |  |
Disclosure of net productive wells and dry wells drilled [line items] |  |  |
Net development wells, Productive | 33 | 84 | 80
Net development wells, Dry |  | 1 |
Net exploratory wells | 1 | 2 |
Discontinued operations - Onshore US Cash Generating Units [member] | United States [member] |  |  |
Disclosure of net productive wells and dry wells drilled [line items] |  |  |
Net development wells, Productive | 33 | 84 | 79
Net development wells, Dry |  | 1 |
Net exploratory wells |  |  |

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