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, 2017		Sep. 30, 2016	Sep. 30, 2017		Sep. 30, 2016
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (loss) before income taxes	$ (1,066)		$ (1,007)	$ (1,616)		$ (3,313)
Interest expense	230		220	680		657
DD&A	1,083		1,069	3,235		3,202
Exploration expense	751		304	2,371		506
(Gains) losses on divestitures, net	194		414	(815)		516
Impairments	0		27	383		61
Total (gains) losses on derivatives, net, less net cash from settlement of commodity derivatives	98		88	(12)		863
Restructuring charges	3		112	20		363
Loss on early extinguishment of debt	0		0	2		124
Less net income (loss) attributable to noncontrolling interests	58	[1]	83	182	[1]	200
Consolidated Adjusted EBITDAX	1,235		1,144	4,066		2,724
Deepwater Horizon [Member] | Judicial Ruling [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other operating expense	0			0		1
Deepwater Horizon [Member] | Pending Litigation [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other operating expense			0
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	$ 0		$ (56)

[1] Presentation has been adjusted to align with the current analysis of segment performance. Net income (loss) attributable to noncontrolling interests, previously reported within the Midstream segment, is now presented within Other and Intersegment Eliminations. Other revenues, previously reported within Other and Intersegment Eliminations, is now presented within the applicable segments.