Acquisitions and Divestitures - Additional Information - 2015 Activity - Canada Divestiture (Detail) - USD ($) $ in Millions	1 Months Ended		3 Months Ended									12 Months Ended
	Jun. 30, 2015	Apr. 30, 2015	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014	[1]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds form sale of operations												$ 0	$ 854	[1]	$ 0
Asset impairments			$ 144	$ 951	$ 238	$ 42	$ 5,100	$ 4,100	$ 660	$ 2,100		$ 1,103	9,472	[1],[2]	$ 7,102	[2]
Loss on sale of upstream assets	$ 139
Canada [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds form sale of operations		$ 854
Kitimat LNG [Member] | Canada [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of ownership		50.00%
Proceeds form sale of operations		$ 344
Asset impairments											$ 655
Upstream Assets [Member] | Canada [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds form sale of operations		$ 510
Loss on sale of upstream assets													$ (146)

[1] Financial information for 2015 and 2014 has been recast to reflect retrospective application of the successful efforts method of accounting. See Note 1.

[2] Financial information for 2015 and 2014 has been recast to reflect retrospective application of the successful efforts method of accounting. See Note 1.