Capitalized Exploratory Well Costs - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($) Well
Capitalized Exploratory Well Costs [Line Items]
Exploratory dry hole costs which were incurred and subsequently expensed	$ 60
Capitalized exploratory well costs that have been capitalized for period greater than one year	$ 1,055
Equus Project On License WA-390-P, Offshore Western Australia
Capitalized Exploratory Well Costs [Line Items]
Capitalized well costs percentage	75.00%
Offshore Ghana
Capitalized Exploratory Well Costs [Line Items]
Capitalized well costs percentage	25.00%
This number of approved appraisal wells is completed | Well	3