Segment Information - Reconciliation of Consolidated Adjusted EBITDAX to Income (Loss) Before Income Taxes (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting [Abstract]
Income (loss) before income taxes	$ (1,007)	$ (3,077)	$ (3,313)	$ (7,520)
(Gains) losses on divestitures, net	414	578	516	1,003
Exploration expense	304	1,074	506	2,260
DD&A	1,069	1,111	3,202	3,581
Impairments	27	758	61	3,571
Interest expense	220	199	657	616
Total (gains) losses on derivatives, net, less net cash from settlement of commodity derivatives	88	360	863	374
Restructuring charges	112	0	363	0
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Loss on early extinguishment of debt	0	0	124	0
Net income (loss) attributable to noncontrolling interests	83	75	200	154
Consolidated Adjusted EBITDAX	1,144	928	2,724	3,762
Certain Other Nonoperating Items [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Certain other nonoperating items	0	0	(56)	22
Deepwater Horizon [Member] | Pending Litigation [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other operating expense		0		4
Deepwater Horizon [Member] | Judicial Ruling [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other operating expense	0		1
Tronox Litigation [Member] | Judicial Ruling [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other operating expense	$ 0	$ 0	0	5
Certain other nonoperating items			$ 0	$ (5,210)