Segment Information - Selected Financial Information for Anadarko's Reporting Segments Table (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Segment Reporting Information [Line Items]
Revenues	$ 4,385		$ 3,440		$ 8,723		$ 7,158
Gains (losses) on divestitures and other, net	54		57		1,560		232
Total revenues and other	4,439		3,497		10,283		7,390
Operating costs and expenses (1)	1,470	[1]	1,225	[1]	2,913	[1]	2,478	[1]
Net cash from settlement of commodity derivatives					186		(65)
Other (income) expense, net	(13)		98		(12)		92
Net income attributable to noncontrolling interests	39		30		82		54
Total expenses and other	1,584		1,247		3,163		2,467
Adjusted EBITDAX	2,857		2,244		7,124		4,921
(Gains) Losses on Derivatives, net [Member] | Commodity Contract [Member]
Segment Reporting Information [Line Items]
Net cash from settlement of commodity derivatives	88		(21)		180		(72)
Gathering, Processing, and Marketing Sales [Member] | Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Segment Reporting Information [Line Items]
Total (gains) losses on derivatives, net included in marketing revenue, less net cash from settlement	2		(6)		4		(2)
Excluding Certain Other Nonoperating Items [Member]
Segment Reporting Information [Line Items]
Other (income) expense, net	(13)	[2]	13	[2]	(12)	[2]	7	[2]
Other and Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues	0		0		0		0
Gains (losses) on divestitures and other, net	45		56		93		227
Total revenues and other	(165)		(96)		(301)		(74)
Operating costs and expenses (1)	7	[1]	7	[1]	25	[1]	27	[1]
Total expenses and other	82		(1)		193		(38)
Adjusted EBITDAX	(247)		(95)		(494)		(36)
Other and Intersegment Eliminations [Member] | (Gains) Losses on Derivatives, net [Member] | Commodity Contract [Member]
Segment Reporting Information [Line Items]
Net cash from settlement of commodity derivatives	88		(21)		180		(72)
Other and Intersegment Eliminations [Member] | Excluding Certain Other Nonoperating Items [Member]
Segment Reporting Information [Line Items]
Other (income) expense, net	(13)	[2]	13	[2]	(12)	[2]	7	[2]
Other and Intersegment Eliminations [Member] | Intersegment Revenues [Member]
Segment Reporting Information [Line Items]
Revenues	(210)		(152)		(394)		(301)
Oil and Gas Exploration and Production Reporting Segment [Member]
Segment Reporting Information [Line Items]
Revenues	2,223		1,587		4,612		3,128
Gains (losses) on divestitures and other, net	10		1		1,470		5
Oil and Gas Exploration and Production Reporting Segment [Member] | Intersegment Revenues [Member]
Segment Reporting Information [Line Items]
Revenues	1,790		1,526		3,343		3,388
Oil and Gas Exploration and Production Reporting Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues and other	4,023		3,114		9,425		6,521
Operating costs and expenses (1)	1,026	[1]	845	[1]	2,038	[1]	1,726	[1]
Total expenses and other	1,026		845		2,038		1,726
Adjusted EBITDAX	2,997		2,269		7,387		4,795
Midstream Reporting Segment [Member]
Segment Reporting Information [Line Items]
Revenues	119		88		239		172
Gains (losses) on divestitures and other, net	(1)		0		(3)		0
Midstream Reporting Segment [Member] | Intersegment Revenues [Member]
Segment Reporting Information [Line Items]
Revenues	326		265		646		518
Midstream Reporting Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues and other	444		353		882		690
Operating costs and expenses (1)	251	[1]	209	[1]	483	[1]	397	[1]
Net income attributable to noncontrolling interests	39		30		82		54
Total expenses and other	290		239		565		451
Adjusted EBITDAX	154		114		317		239
Marketing Reporting Segment [Member]
Segment Reporting Information [Line Items]
Revenues	2,043		1,765		3,872		3,858
Gains (losses) on divestitures and other, net	0		0		0		0
Marketing Reporting Segment [Member] | Intersegment Revenues [Member]
Segment Reporting Information [Line Items]
Revenues	(1,906)		(1,639)		(3,595)		(3,605)
Marketing Reporting Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues and other	137		126		277		253
Operating costs and expenses (1)	186	[1]	164	[1]	367	[1]	328	[1]
Total expenses and other	186		164		367		328
Adjusted EBITDAX	(47)		(44)		(86)		(77)
Marketing Reporting Segment [Member] | Operating Segments [Member] | Gathering, Processing, and Marketing Sales [Member] | Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Segment Reporting Information [Line Items]
Total (gains) losses on derivatives, net included in marketing revenue, less net cash from settlement	$ 2		$ (6)		$ 4		$ (2)

[1] Operating costs and expenses excludes exploration expense, DD&A, impairments, Deepwater Horizon settlement and related costs, and Algeria exceptional profits tax settlement since these expenses are excluded from Adjusted EBITDAX.

[2] Other (income) expense, net excludes certain other nonoperating items since these expenses are excluded from Adjusted EBITDAX.