Segment Information - Reconciliation of Consolidated Adjusted EBITDAX to Income (Loss) Before Income Taxes (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting [Abstract]
Income (loss) before income taxes	$ (925)	$ 185	$ (2,306)	$ (4,443)
(Gains) losses on divestitures, net	(104)	(91)	102	425
Exploration expense	76	103	202	1,186
DD&A	984	1,214	2,133	2,470
Impairments	18	30	34	2,813
Interest expense	217	201	437	417
Total (gains) losses on derivatives, net, less net cash from settlement of commodity derivatives	371	(229)	775	14
Restructuring charges	48	0	251	0
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Loss on early extinguishment of debt	124	0	124	0
Net income (loss) attributable to noncontrolling interests	81	47	117	79
Consolidated Adjusted EBITDAX	880	1,548	1,580	2,834
Certain Other Nonoperating Items [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Certain other nonoperating items	(56)	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)