Exploration and Evaluation Assets (Tables)

12 Months Ended

Dec. 31, 2019

Exploration For And Evaluation Of Mineral Resources [Abstract]

Detailed information about exploration and evaluation assets

	Exploration and Production								Oil Sands  Mining and Upgrading			Total
	North America			North Sea		Offshore Africa
Cost
At December 31, 2017	$	2,282		$	—	$	91		$	259		$	2,632
Additions	245			—		35			222			502
Transfers to property, plant and equipment	(175		)	—		—			(222		)	(397		)
Disposals/derecognitions and other	(4		)	—		(89		)	(7		)	(100		)
At December 31, 2018	2,348			—		37			252			2,637
Additions	38			—		33			—			71
Acquisition of Devon assets (note 7)	91			—		—			—			91
Transfers to property, plant and equipment	(219		)	—		—			—			(219		)
Foreign exchange adjustments	—			—		(1		)	—			(1		)
At December 31, 2019	$	2,258		$	—	$	69		$	252		$	2,579