Capitalized Exploratory Well Costs (Details) - USD ($)	3 Months Ended	9 Months Ended
	Jun. 30, 2016	Sep. 30, 2016	Dec. 31, 2015
Extractive Industries [Abstract]
Capitalized exploratory well costs		$ 283,000,000	$ 245,000,000
Capitalized exploratory well costs that have been capitalized for period greater than one year		32,000,000	$ 61,000,000
Increase of capitalized exploratory well costs that have been capitalized for a period greater than one year	$ 32,000,000	$ 0