Supplemental Cash Flow Information (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash paid (received)
Interest, net of amounts capitalized	$ 471	$ 449
Income taxes, net of refunds	53	162
Non-cash investing activities
Fair value of properties and equipment acquired	7	553
Asset retirement cost additions	162	138
Accruals of property, plant, and equipment	1,036	696
Net liabilities assumed (divested) in acquisitions and divestitures	(97)	(100)
Non-cash investing and financing activities
Deferred drilling lease liability	0	13
Settlement of tangible equity units	$ 300	$ 0