Supplemental Cash Flow Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash paid (received)
Interest, net of amounts capitalized	$ 326	$ 308
Income taxes, net of refunds	12	1
Non-cash investing activities
Fair value of properties and equipment acquired	2	549
Asset retirement cost additions	63	61
Accruals of property, plant, and equipment	965	608
Net liabilities assumed (divested) in acquisitions and divestitures	(25)	(82)
Non-cash investing and financing activities
Deferred drilling lease liability	$ 0	$ 7