Income Taxes - Deferred Tax Assets (Liabilities) Table (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets (Liabilities), Net [Line Items]
Other	$ (470)	$ (351)
Gross long-term deferred tax liabilities	(7,654)	(10,792)
Foreign and state net operating loss carryforwards	586	558
U.S. foreign tax credit carryforwards	1,254	166
Compensation and benefit plans	615	701
Mark to market on derivatives	441	354
Other	761	760
Gross long-term deferred tax assets	3,657	3,129
Valuation allowances on deferred tax assets not expected to be realized	(1,403)	(864)
Net long-term deferred tax assets	2,254	2,265
Total deferred taxes	(5,400)	(8,527)
Judicial Ruling [Member] | Tronox Litigation [Member]
Deferred Tax Assets (Liabilities), Net [Line Items]
Settlement agreement related to the Tronox Adversary Proceeding	0	590
Oil and Gas Exploration and Development Operations
Deferred Tax Assets (Liabilities), Net [Line Items]
Deferred tax liabilities - property, plant, and equipment	(5,643)	(8,418)
Midstream and Other Depreciable Properties [Member]
Deferred Tax Assets (Liabilities), Net [Line Items]
Deferred tax liabilities - property, plant, and equipment	(1,049)	(1,611)
Mineral Operations [Member]
Deferred Tax Assets (Liabilities), Net [Line Items]
Deferred tax liabilities - property, plant, and equipment	$ (492)	$ (412)