Dispositions - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from asset sales	$ 607	$ 3,296	$ 140
Gain (loss) on asset sales, pre-tax	32	(86)	23
Loss included recognition earnings for cumulative translation adjustments	0	900	0
Miscellaneous Non-core Assets
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from asset sales		194	100
Gain (loss) on asset sales, pre-tax		12	23
Gain (loss) on asset sale, after-tax		12	$ 14
Ghana
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Agreement entered to sell interest, total consideration	100
Gain (loss) on asset sales, pre-tax	10
Gain (loss) on asset sale, after-tax	10
Payment upon closing | Ghana
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from asset sales	25
Payable upon approval of the Plan of Development | Ghana
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Agreement entered to sell interest, total consideration	75
Utica Shale Play, Eastern Ohio | Eastern Ohio
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from asset sales	396
Gain (loss) on asset sales, pre-tax	14
Gain (loss) on asset sale, after-tax	$ 14
Permian Basin
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from asset sales		597
Gain (loss) on asset sales, pre-tax		273
Gain (loss) on asset sale, after-tax		280
Permian Basin | Exploration and Production
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain (loss) on asset sale, after-tax		314
Permian Basin | Midstream
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain (loss) on asset sale, after-tax		(34)
Equatorial Guinea
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from asset sales		449
Gain (loss) on asset sales, pre-tax		486
Gain (loss) on asset sale, after-tax		486
Offshore Norway
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from asset sales		2,056
Gain (loss) on asset sales, pre-tax		(857)
Gain (loss) on asset sale, after-tax		$ (857)