Income Taxes - Deferred Tax Assets (Liabilities) Table (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Components of Deferred Tax Assets and Liabilities [Abstract]
Current deferred tax assets	$ 412	$ 328
Valuation allowances on deferred tax assets not expected to be realized	(52)	0
Net current deferred tax assets	360	328
Deferred Tax Assets (Liabilities), Net [Line Items]
Other	(499)	(152)
Gross long-term deferred tax liabilities	(10,708)	(10,538)
Oil and gas exploration and development costs	94	762
Net operating loss carryforward	599	477
Foreign tax credit carryforward and alternative minimum tax credit carryforward	325	450
Other	1,211	1,012
Gross long-term deferred tax assets	2,229	2,701
Valuation allowances on deferred tax assets not expected to be realized	(766)	(922)
Net long-term deferred tax assets	1,463	1,779
Net long-term deferred tax liabilities	(9,245)	(8,759)
Total deferred taxes	(8,885)	(8,431)
Oil and Gas Exploration and Development Operations [Member]
Deferred Tax Assets (Liabilities), Net [Line Items]
Deferred tax liabilities - property, plant, and equipment	(8,213)	(8,683)
Mineral Operations [Member]
Deferred Tax Assets (Liabilities), Net [Line Items]
Deferred tax liabilities - property, plant, and equipment	(410)	(408)
Midstream and Other Depreciable Properties [Member]
Deferred Tax Assets (Liabilities), Net [Line Items]
Deferred tax liabilities - property, plant, and equipment	$ (1,586)	$ (1,295)