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Number of Crude Oil and Natural Gas Wells Drilled and Completed (Parenthetical) (Detail) - Wells
 12 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2019
Disclosure of net productive wells and dry wells drilled [line items]      
Net development wells, Productive 3 1 34
Net exploratory wells 1 2 7
Discontinued operations [member] | Onshore US [Member]      
Disclosure of net productive wells and dry wells drilled [line items]      
Net development wells, Productive 0 0 33
Net exploratory wells 0 0 0