Anadarko Petroleum 10-K 28 Feb 14 2013 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Billions, except Share data, unless otherwise specified	Dec. 31, 2013	Jan. 31, 2014	Jun. 28, 2013
Document And Entity Information [Abstract]	'	'	'
Entity Registrant Name	'ANADARKO PETROLEUM CORP	'	'
Entity Central Index Key	'0000773910	'	'
Document Type	'10-K	'	'
Document Period End Date	31-Dec-13	'	'
Amendment Flag	'false	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Entity Common Stock, Shares Outstanding	'	503,767,298	'
Entity Well Known Seasoned Issuer	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Public Float	'	'	$43.10

CONSOLIDATED_STATEMENTS_OF_INC

CONSOLIDATED STATEMENTS OF INCOME (USD $)	12 Months Ended
Share data in Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues and Other	'	'	'
Natural-gas sales	$3,388,000,000	$2,444,000,000	$3,300,000,000
Oil and condensate sales	9,178,000,000	8,728,000,000	8,072,000,000
Natural-gas liquids sales	1,262,000,000	1,224,000,000	1,462,000,000
Gathering, processing, and marketing sales	1,039,000,000	911,000,000	1,048,000,000
Gains (losses) on divestitures and other, net	-286,000,000	104,000,000	85,000,000
Total	14,581,000,000	13,411,000,000	13,967,000,000
Costs and Expenses	'	'	'
Oil and gas operating	1,092,000,000	976,000,000	993,000,000
Oil and gas transportation and other	1,022,000,000	955,000,000	891,000,000
Exploration	1,329,000,000	1,946,000,000	1,076,000,000
Gathering, processing, and marketing	869,000,000	763,000,000	791,000,000
General and administrative	1,090,000,000	1,246,000,000	1,060,000,000
Depreciation, depletion, and amortization	3,927,000,000	3,964,000,000	3,830,000,000
Other taxes	1,077,000,000	1,224,000,000	1,492,000,000
Impairments	794,000,000	389,000,000	1,774,000,000
Algeria exceptional profits tax settlement	33,000,000	-1,797,000,000	0
Deepwater Horizon settlement and related costs	15,000,000	18,000,000	3,930,000,000
Total	11,248,000,000	9,684,000,000	15,837,000,000
Operating Income (Loss)	3,333,000,000	3,727,000,000	-1,870,000,000
Other (Income) Expense	'	'	'
Interest expense	686,000,000	742,000,000	839,000,000
Statement [Line Items]	'	'	'
(Gains) losses on derivatives, net	-392,000,000	-308,000,000	469,000,000
Other (income) expense, net	89,000,000	-4,000,000	4,000,000
Tronox-related contingent loss	850,000,000	-250,000,000	250,000,000
Total	1,227,000,000	162,000,000	1,554,000,000
Income (Loss) Before Income Taxes	2,106,000,000	3,565,000,000	-3,424,000,000
Income tax expense (benefit)	1,165,000,000	1,120,000,000	-856,000,000
Net Income (Loss)	941,000,000	2,445,000,000	-2,568,000,000
Net income attributable to noncontrolling interests	140,000,000	54,000,000	81,000,000
Net Income (Loss) Attributable to Common Stockholders	801,000,000	2,391,000,000	-2,649,000,000
Per Common Share	'	'	'
Net income (loss) attributable to common stockholders—basic	$1.58	$4.76	($5.32)
Net income (loss) attributable to common stockholders—diluted	$1.58	$4.74	($5.32)
Average Number of Common Shares Outstanding—Basic	502	500	498
Average Number of Common Shares Outstanding—Diluted	505	502	498
Dividends (per Common Share)	$0.54	$0.36	$0.36
Commodity Contract and Interest-Rate Swap [Member]	'	'	'
Statement [Line Items]	'	'	'
(Gains) losses on derivatives, net	($398,000,000)	($326,000,000)	$461,000,000

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Statement of Comprehensive Income [Abstract]	'		'		'
Net Income (Loss)	$941		$2,445		($2,568)
Other Comprehensive Income (Loss), net of taxes	'		'		'
Reclassification of previously deferred derivative losses to (gains) losses on derivatives, net (1)	7	[1]	8	[1]	10	[1]
Adjustments for pension and other postretirement plans	'		'		'
Net gain (loss) incurred during period (2)	264	[2]	-99	[2]	-136	[2]
Prior service credit (cost) incurred during period (3)	0	[3]	0	[3]	7	[3]
Amortization of net actuarial (gain) loss to general and administrative expense (4)	83	[4]	61	[4]	54	[4]
Amortization of net prior service (credit) cost to general and administrative expense	1		2		2
Total adjustments for pension and other postretirement plans	348		-36		-73
Total	355		-28		-63
Comprehensive Income (Loss)	1,296		2,417		-2,631
Comprehensive income attributable to noncontrolling interests	140		54		81
Comprehensive Income (Loss) Attributable to Common Stockholders	$1,156		$2,363		($2,712)
[1]	Net of income tax benefit (expense) of $(4) million in 2013, $(4) million in 2012, and $(5) million in 2011.
[2]	Net of income tax benefit (expense) of $(152) million in 2013, $56 million in 2012, and $77 million in 2011.
[3]	Net of income tax benefit (expense) of $(5) million in 2011.
[4]	Net of income tax benefit (expense) of $(49) million in 2013, $(32) million in 2012, and $(31) million in 2011.

CONSOLIDATED_STATEMENTS_OF_COM1

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of Comprehensive Income [Abstract]	'	'	'
Reclassification of previously deferred derivative losses to (gains) losses on derivatives, net, tax effect	($4)	($4)	($5)
Net gain (loss) incurred during period, tax effect	-152	56	77
Prior service credit (cost) incurred during period, tax effect	'	'	-5
Amortization of net actuarial (gain) loss to general and administrative expense, tax effect	($49)	($32)	($31)

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Current Assets	'	'
Cash and cash equivalents	$3,698	$2,471
Accounts receivable (net of allowance of $5 million and $7 million)	'	'
Customers	1,481	1,473
Others	1,241	1,274
Algeria exceptional profits tax settlement	0	730
Other current assets	688	847
Total	7,108	6,795
Properties and Equipment	'	'
Cost	71,244	63,598
Less accumulated depreciation, depletion, and amortization	30,315	25,200
Net properties and equipment	40,929	38,398
Other Assets	2,082	1,716
Goodwill and Other Intangible Assets	5,662	5,680
Total Assets	55,781	52,589
Current Liabilities	'	'
Accounts payable	3,530	2,989
Current asset retirement obligations	409	298
Accrued expenses	1,264	707
Current portion of long-term debt	500	0
Total	5,703	3,994
Long-term Debt	13,065	13,269
Other Long-term Liabilities	'	'
Deferred income taxes	9,245	8,759
Asset retirement obligations	1,613	1,587
Tronox-related contingent liability	850	0
Other	1,655	3,098
Total	13,363	13,444
Stockholders' equity	'	'
Common stock, par value $0.10 per share (1.0 billion shares authorized, 522.5 million and 518.6 million shares issued)	52	51
Paid-in capital	8,629	8,230
Retained earnings	14,356	13,829
Treasury stock (18.8 million and 18.1 million shares)	-895	-841
Accumulated other comprehensive income (loss)	-285	-640
Total Stockholders’ Equity	21,857	20,629
Noncontrolling interests	1,793	1,253
Total Equity	23,650	21,882
Total Liabilities and Equity	$55,781	$52,589

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]	'	'
Allowance for uncollectible accounts	$5	$7
Common stock, par value	$0.10	$0.10
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	522,500,000	518,600,000
Treasury stock, shares	18,800,000	18,100,000

CONSOLIDATED_STATEMENTS_OF_EQU

CONSOLIDATED STATEMENTS OF EQUITY (USD $)		Total		Common Stock [Member]	Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]
In Millions
Balance at Dec. 31, 2010		$21,439		$51	$7,496	$14,449	($763)	($549)	$755
Net income (loss)		-2,568		'	'	-2,649	'	'	81
Common stock issued		161		'	161	'	'	'	'
Dividends—common stock		-181		'	'	-181	'	'	'
Repurchase of common stock		-41		'	'	'	-41	'	'
Subsidiary equity transactions		301		'	32	'	'	'	269
Conversion of subordinated limited partner units to common units (1)	[1]	'		'	162	'	'	'	-162
Distributions to noncontrolling interest owners		-82		'	'	'	'	'	-82
Contributions from noncontrolling interest owners		17		'	'	'	'	'	17
Reclassification of previously deferred derivative losses to (gains) losses on derivatives, net		10	[2]	'	'	'	'	10	'
Adjustments for pension and other postretirement plans		-73		'	'	'	'	-73	'
Balance at Dec. 31, 2011		18,983		51	7,851	11,619	-804	-612	878
Net income (loss)		2,445		'	'	2,391	'	'	54
Common stock issued		249		'	249	'	'	'	'
Dividends—common stock		-181		'	'	-181	'	'	'
Repurchase of common stock		-37		'	'	'	-37	'	'
Subsidiary equity transactions		547		'	130	'	'	'	417
Distributions to noncontrolling interest owners		-112		'	'	'	'	'	-112
Contributions from noncontrolling interest owners		16		'	'	'	'	'	16
Reclassification of previously deferred derivative losses to (gains) losses on derivatives, net		8	[2]	'	'	'	'	8	'
Adjustments for pension and other postretirement plans		-36		'	'	'	'	-36	'
Balance at Dec. 31, 2012		21,882		51	8,230	13,829	-841	-640	1,253
Net income (loss)		941		'	'	801	'	'	140
Common stock issued		293		1	292	'	'	'	'
Dividends—common stock		-274		'	'	-274	'	'	'
Repurchase of common stock		-54		'	'	'	-54	'	'
Subsidiary equity transactions		661		'	107	'	'	'	554
Distributions to noncontrolling interest owners		-156		'	'	'	'	'	-156
Contributions from noncontrolling interest owners		2		'	'	'	'	'	2
Reclassification of previously deferred derivative losses to (gains) losses on derivatives, net		7	[2]	'	'	'	'	7	'
Adjustments for pension and other postretirement plans		348		'	'	'	'	348	'
Balance at Dec. 31, 2013		$23,650		$52	$8,629	$14,356	($895)	($285)	$1,793
[1]	Includes $92 million of tax associated with subsidiary equity transactions that occurred prior to the conversion of subordinated limited partner units to common units.
[2]	Net of income tax benefit (expense) of $(4) million in 2013, $(4) million in 2012, and $(5) million in 2011.

CONSOLIDATED_STATEMENTS_OF_EQU1

CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2011
Paid-in Capital [Member]	'
Conversion of subordinated limited partner units to common units, tax	$92
Noncontrolling Interests [Member]	'
Conversion of subordinated limited partner units to common units, tax	($92)

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash Flows from Operating Activities	'	'	'
Net income (loss)	$941	$2,445	($2,568)
Adjustments to reconcile net income (loss) to net cash provided by operating activities	'	'	'
Depreciation, depletion, and amortization	3,927	3,964	3,830
Deferred income taxes	90	164	-1,461
Dry hole expense and impairments of unproved properties	864	1,544	625
Impairments	794	389	1,774
(Gains) losses on divestitures, net	470	71	-22
Total (gains) losses on derivatives, net	-392	-308	469
Net cash received in settlement of derivative instruments	85	685	147
Other	246	232	204
Changes in assets and liabilities	'	'	'
Deepwater Horizon settlement and related costs	-2	24	-18
Algeria exceptional profits tax settlement	730	-791	0
Tronox-related contingent loss	850	-250	250
(Increase) decrease in accounts receivable	-11	520	-993
Increase (decrease) in accounts payable and accrued expenses	150	-476	284
Other items—net	146	126	-16
Net cash provided by (used in) operating activities	8,888	8,339	2,505
Cash Flows from Investing Activities	'	'	'
Additions to properties and equipment and dry hole costs	-7,721	-7,242	-5,650
Acquisition of businesses	-473	0	-802
Divestitures of properties and equipment and other assets	567	657	555
Other—net	-589	-284	-78
Net cash provided by (used in) investing activities	-8,216	-6,869	-5,975
Cash Flows from Financing Activities	'	'	'
Borrowings, net of issuance costs	958	1,042	3,551
Repayments of debt	-710	-3,044	-1,154
Repayment of capital lease obligation	0	0	-108
Increase (decrease) in outstanding checks	-13	-69	149
Dividends paid	-274	-181	-181
Repurchase of common stock	-54	-37	-41
Issuance of common stock, including tax benefit on share-based compensation awards	146	103	30
Sale of subsidiary units	724	623	328
Distributions to noncontrolling interest owners	-156	-112	-82
Contributions from noncontrolling interest owners	2	16	17
Other financing activities	0	0	1
Net cash provided by (used in) financing activities	623	-1,659	2,510
Effect of Exchange Rate Changes on Cash	-68	-37	-23
Net Increase (Decrease) in Cash and Cash Equivalents	1,227	-226	-983
Cash and Cash Equivalents at Beginning of Period	2,471	2,697	3,680
Cash and Cash Equivalents at End of Period	$3,698	$2,471	$2,697

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Summary of Significant Accounting Policies	'
	1. Summary of Significant Accounting Policies
	General  Anadarko Petroleum Corporation is engaged in the exploration, development, production, and marketing of natural gas, crude oil, condensate, natural gas liquids (NGLs), and anticipated production of liquefied natural gas (LNG). In addition, the Company engages in the gathering, processing, treating, and transporting of natural gas, crude oil, and NGLs. The Company also participates in hard-minerals royalty arrangements. Unless the context otherwise requires, the terms “Anadarko” and “Company” refer to Anadarko Petroleum Corporation and its consolidated subsidiaries.
	Basis of Presentation  The Consolidated Financial Statements have been prepared in conformity with accounting principles generally accepted in the United States. The Consolidated Financial Statements include the accounts of Anadarko and entities in which it holds a controlling interest. All intercompany transactions have been eliminated. Undivided interests in oil and natural-gas exploration and production joint ventures are consolidated on a proportionate basis. Investments in non-controlled entities, over which Anadarko has the ability to exercise significant influence over operating and financial policies, are accounted for using the equity method. In applying the equity method of accounting, the investments are initially recognized at cost, and subsequently adjusted for the Company’s proportionate share of earnings, losses, and distributions. Other investments are carried at original cost. Investments accounted for using the equity method and cost method are reported as a component of other assets. Certain prior-period amounts have been reclassified to conform to the current-year presentation.
	Use of Estimates  The preparation of financial statements in accordance with accounting principles generally accepted in the United States requires management to make informed judgments and estimates that affect the reported amounts of assets, liabilities, revenues, and expenses. Management evaluates its estimates and related assumptions regularly, including those related to proved reserves; the value of properties and equipment; goodwill; intangible assets; asset retirement obligations; litigation liabilities; environmental liabilities; pension assets, liabilities, and costs; income taxes; and fair values. Changes in facts and circumstances or additional information may result in revised estimates, and actual results may differ from these estimates.
	Fair Value  Fair value is defined as the price that would be received to sell an asset or the price paid to transfer a liability in an orderly transaction between market participants at the measurement date. Inputs used in determining fair value are characterized according to a hierarchy that prioritizes those inputs based on the degree to which they are observable. The three input levels of the fair-value hierarchy are as follows:
	Level 1—Inputs represent quoted prices in active markets for identical assets or liabilities (for example, exchange-traded commodity derivatives).
	Level 2—Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly (for example, quoted market prices for similar assets or liabilities in active markets or quoted market prices for identical assets or liabilities in markets not considered to be active, inputs other than quoted prices that are observable for the asset or liability, or market-corroborated inputs).
	Level 3—Inputs that are not observable from objective sources, such as the Company’s internally developed assumptions used in pricing an asset or liability (for example, an estimate of future cash flows used in the Company’s internally developed present value of future cash flows model that underlies the fair-value measurement).
	In determining fair value, the Company uses observable market data when available, or models that incorporate observable market data. In addition to market information, the Company incorporates transaction-specific details that, in management’s judgment, market participants would take into account in measuring fair value.
	1. Summary of Significant Accounting Policies (Continued)
	In arriving at fair-value estimates, the Company uses the most observable inputs available for the valuation technique employed. If a fair-value measurement reflects inputs at multiple levels within the hierarchy, the fair-value measurement is characterized based on the lowest level of input that is significant to the fair-value measurement. For Anadarko, recurring fair-value measurements are performed for interest-rate derivatives, commodity derivatives, and investments in trading securities.
	The carrying amount of cash and cash equivalents, accounts receivable, and accounts payable reported on the Consolidated Balance Sheets approximates fair value. The fair value of debt is the estimated amount the Company would have to pay to repurchase its debt, including any premium or discount attributable to the difference between the stated interest rate and market interest rate at each balance sheet date. Debt fair values, as disclosed in Note 12—Debt and Interest Expense, are based on quoted market prices for identical instruments, if available, or based on valuations of similar debt instruments.
	Non-financial assets and liabilities initially measured at fair value include certain assets and liabilities acquired in a business combination or through a non-monetary exchange transaction, intangible assets, goodwill, asset retirement obligations, exit or disposal costs, and capital lease assets where the present value of lease payments is greater than the fair value of the leased asset.
	Revenues  The Company’s natural gas is sold primarily to interstate and intrastate natural-gas pipelines, direct end-users, industrial users, local distribution companies, and natural-gas marketers. Oil and condensate are sold primarily to marketers, gatherers, and refiners. NGLs are sold primarily to direct end-users, refiners, and marketers.
	The Company recognizes sales revenues for natural gas, oil and condensate, and NGLs based on the amount of each product sold to purchasers when delivery to the purchaser has occurred and title has transferred. This occurs when product has been delivered to a pipeline or when a tanker lifting has occurred. The Company follows the sales method of accounting for natural-gas production imbalances. If the Company’s sales volumes for a well exceed the Company’s proportionate share of production from the well, a liability is recognized to the extent that the Company’s share of estimated remaining recoverable reserves from the well is insufficient to satisfy this imbalance. No receivables are recorded for those wells on which the Company has taken less than its proportionate share of production.
	Anadarko provides gathering, processing, treating, and transporting services pursuant to a variety of contracts. Under these arrangements, the Company receives fees, or retains a percentage of products or a percentage of the proceeds from the sale of products and recognizes revenue at the time the services are performed or product is sold. These revenues are included in gathering, processing, and marketing sales in the Consolidated Statements of Income.
	Marketing margins related to the Company’s production are included in natural-gas sales, oil and condensate sales, and NGLs sales. Marketing margins related to sales of commodities purchased from third parties and gains and losses on derivatives related to such marketing activities are included in gathering, processing, and marketing sales in the Consolidated Statements of Income.
	The Company enters into buy/sell arrangements related to the transportation of a portion of its crude-oil production. Under these arrangements, barrels are sold to a third party at a location-based contract price and subsequently repurchased by the Company at a downstream location. The difference in value between the sale and purchase price represents the transportation fee from the lease or certain gathering locations to more liquid markets. These arrangements are often required by private transporters. These transactions are reported on a net basis and included in oil and gas transportation in the Consolidated Statements of Income.
	Cash Equivalents  The Company considers all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents.
	1. Summary of Significant Accounting Policies (Continued)
	Accounts Receivable and Allowance for Uncollectible Accounts  The Company conducts credit analyses of customers prior to making any sales to new customers or increasing credit for existing customers. Based on these analyses, the Company may require a standby letter of credit or a financial guarantee. The Company charges uncollectible accounts receivable against the allowance for uncollectible accounts when it determines collection will no longer be pursued.
	Inventories  Commodity inventories are stated at the lower of average cost or market.
	Properties and Equipment  Properties and equipment are stated at cost less accumulated depreciation, depletion, and amortization expense (DD&A). Costs of improvements that appreciably improve the efficiency or productive capacity of existing properties or extend their lives are capitalized. Maintenance and repairs are expensed as incurred. Upon retirement or sale, the cost of properties and equipment, net of the related accumulated DD&A, is removed and, if appropriate, gain or loss is recognized in gains (losses) on divestitures and other, net.
	Oil and Gas Properties  The Company applies the successful efforts method of accounting for oil and gas properties. Exploration costs such as exploratory geological and geophysical costs, delay rentals, and exploration overhead are charged against earnings as incurred. If an exploratory well provides evidence to justify potential completion as a producing well, drilling costs associated with the well are initially capitalized, or suspended, pending a determination as to whether a commercially sufficient quantity of proved reserves can be attributed to the area as a result of drilling. This determination may take longer than one year in certain areas (generally in deepwater and international locations) depending on, among other things, the amount of hydrocarbons discovered, the outcome of planned geological and engineering studies, the need for additional appraisal drilling activities to determine whether the discovery is sufficient to support an economic development plan, and government sanctioning of development activities in certain international locations. At the end of each quarter, management reviews the status of all suspended exploratory well costs in light of ongoing exploration activities—in particular, whether the Company is making sufficient progress in its ongoing exploration and appraisal efforts or, in the case of discoveries requiring government sanctioning, whether development negotiations are underway and proceeding as planned. If management determines that future appraisal drilling or development activities are unlikely to occur, associated suspended exploratory well costs are expensed.
	Acquisition costs of unproved properties are periodically assessed for impairment and are transferred to proved oil and gas properties to the extent the costs are associated with successful exploration activities. Significant undeveloped leases are assessed individually for impairment, based on the Company’s current exploration plans, and a valuation allowance is provided if impairment is indicated. Unproved oil and gas properties with individually insignificant lease acquisition costs are amortized on a group basis (thereby establishing a valuation allowance) over the average lease term at rates that provide for full amortization of unsuccessful leases upon lease expiration or abandonment. Costs of expired or abandoned leases are charged against the valuation allowance, while costs of productive leases are transferred to proved oil and gas properties. Costs of maintaining and retaining unproved properties, as well as amortization of individually insignificant leases and impairment of unsuccessful leases, are included in exploration expense in the Consolidated Statements of Income.
	Capitalized Interest  For significant projects, interest is capitalized as part of the historical cost of developing and constructing assets. Significant oil and gas investments in unproved properties, significant exploration and development projects that have not commenced production, significant midstream development activities that are in progress, and investments in equity method affiliates that are undergoing the construction of assets that have not commenced principle operations qualify for interest capitalization. Interest is capitalized until the asset is ready for service. Capitalized interest is determined by multiplying the Company’s weighted-average borrowing cost on debt by the average amount of qualifying costs incurred. Once an asset subject to interest capitalization is completed and placed in service, the associated capitalized interest is expensed through depreciation or impairment. See Note 12—Debt and Interest Expense.
	1. Summary of Significant Accounting Policies (Continued)
	Asset Retirement Obligations  Asset retirement obligations (AROs) associated with the retirement of tangible long-lived assets are recognized as liabilities with an increase to the carrying amounts of the related long-lived assets in the period incurred. The cost of the tangible asset, including the asset retirement cost, is depreciated over the useful life of the asset. AROs are recorded at estimated fair value, measured by reference to the expected future cash outflows required to satisfy the retirement obligations discounted at the Company’s credit-adjusted risk-free interest rate. Accretion expense is recognized over time as the discounted liabilities are accreted to their expected settlement value. If estimated future costs of AROs change, an adjustment is recorded to both the asset retirement obligation and the long-lived asset. Revisions to estimated AROs can result from changes in retirement cost estimates, revisions to estimated inflation rates, and changes in the estimated timing of abandonment. See Note 7—Asset Retirement Obligations.
	Impairments  Properties and equipment are reviewed for impairment when facts and circumstances indicate that net book values may not be recoverable. In performing this review, an undiscounted cash flow test is performed at the lowest level for which identifiable cash flows are independent of cash flows from other assets. If the sum of the undiscounted future net cash flows is less than the net book value of the property, an impairment loss is recognized for the excess, if any, of the property’s net book value over its estimated fair value. See Note 5—Impairments.
	Depreciation, Depletion, and Amortization  Costs of drilling and equipping successful wells, costs to construct or acquire facilities other than offshore platforms, associated asset retirement costs, and capital lease assets used in oil and gas activities are depreciated using the unit-of-production (UOP) method based on total estimated proved developed oil and gas reserves. Costs of acquiring proved properties, including leasehold acquisition costs transferred from unproved properties and costs to construct or acquire offshore platforms and associated asset retirement costs, are depleted using the UOP method based on total estimated proved developed and undeveloped reserves. Mineral properties are also depleted using the UOP method. All other properties are stated at historical acquisition cost, net of impairments, and are depreciated using the straight-line method over the useful lives of the assets, which range from 3 to 15 years for furniture and equipment, up to 40 years for buildings, and up to 47 years for gathering facilities.
	Goodwill and Other Intangible Assets  Goodwill is subject to annual impairment testing at October 1 (or more frequent testing as circumstances dictate). Anadarko has allocated goodwill to the following reporting units: oil and gas exploration and production, other gathering and processing, Western Gas Partners, LP (WES) gathering and processing, and transportation. Changes in goodwill may result from, among other things, impairments, future acquisitions, or future divestitures. See Note 8—Goodwill and Other Intangible Assets.
	Other intangible assets represent contractual rights obtained in connection with business combinations that had favorable contractual terms relative to market at the acquisition date. Other intangible assets are amortized over their estimated useful lives and are assessed for impairment whenever impairment indicators are present. See Note 8—Goodwill and Other Intangible Assets.
	Derivative Instruments  Anadarko uses derivative instruments to manage its exposure to cash-flow variability from commodity-price and interest-rate risk. Derivatives are carried on the balance sheet at fair value and are included in other current assets, other assets, accrued expenses, or other long-term liabilities, depending on the derivative position and the expected timing of settlement, unless they satisfy the normal purchases and sales exception criteria. Where the Company has the contractual right and intends to net settle, derivative assets and liabilities are reported on a net basis.
	Gains and losses on derivative instruments are recognized currently in earnings. Net losses attributable to derivatives previously subject to hedge accounting reside in accumulated other comprehensive income and will be reclassified to earnings in future periods as the economic transactions to which the derivatives relate affect earnings. See Note 11—Derivative Instruments.
	1. Summary of Significant Accounting Policies (Continued)
	Accounts Payable  Accounts payable included liabilities of $326 million at December 31, 2013, and $339 million at December 31, 2012, representing the amount by which checks issued, but not presented to the Company’s banks for collection, exceeded balances in applicable bank accounts. Changes in these liabilities are reflected in cash flows from financing activities.
	Legal Contingencies  The Company is subject to legal proceedings, claims, and liabilities that arise in the ordinary course of business. Except for legal contingencies acquired in a business combination, which are recorded at fair value at the time of acquisition, the Company accrues losses associated with legal claims when such losses are probable and reasonably estimable. If the Company determines that a loss is probable and cannot estimate a specific amount for that loss, but can estimate a range of loss, the best estimate within the range is accrued. If no amount within the range is a better estimate than any other, the minimum amount of the range is accrued. Estimates are adjusted as additional information becomes available or circumstances change. Legal defense costs associated with loss contingencies are expensed in the period incurred. See Note 17—Contingencies.
	Environmental Contingencies  The Company is subject to various environmental-remediation and reclamation obligations arising from federal, state, and local laws and regulations. Except for environmental contingencies acquired in a business combination, which are recorded at fair value at the time of acquisition, the Company accrues losses associated with environmental obligations when such losses are probable and reasonably estimable. Accruals for estimated environmental losses are recognized no later than at the time the remediation feasibility study, or the evaluation of response options, is complete. These accruals are adjusted as additional information becomes available or circumstances change. Future environmental expenditures are not discounted to their present value. Recoveries of environmental costs from other parties are recorded separately as assets at their undiscounted value when receipt of such recoveries is probable. See Note 17—Contingencies.
	Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans  The Company measures pension plan assets at fair value. Defined-benefit plan obligations and costs are actuarially determined, incorporating the use of various assumptions. Critical assumptions for pension and other postretirement plans include the discount rate, the expected long-term rate of return on plan assets (for funded pension plans), the rate of future compensation increases, and the health care cost trend rate (for postretirement plans). Other assumptions involve demographic factors such as retirement age, mortality, and turnover. The Company evaluates and updates its actuarial assumptions at least annually.
	The Company amortizes prior service costs (credits) on a straight-line basis over the average remaining service period of employees expected to receive benefits under each plan. Actuarial gains and losses that exceed 10% of the greater of the projected benefit obligation and the market-related value of assets are amortized over the average remaining service period of participating employees expected to receive benefits under each plan. See Note 22—Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans.
	Noncontrolling Interests  Noncontrolling interests represent third-party ownership in the net assets of the Company’s consolidated subsidiaries and are presented as a component of equity. Changes in Anadarko’s ownership interests in subsidiaries that do not result in deconsolidation are recognized in equity. See Note 9—Noncontrolling Interests.
	1. Summary of Significant Accounting Policies (Continued)
	Income Taxes  The Company files various U.S. federal, state, and foreign income tax returns. Deferred federal, state, and foreign income taxes are provided on temporary differences between the financial statement carrying amounts of assets and liabilities and their respective tax basis. The Company routinely assesses the realizability of its deferred tax assets. If the Company concludes that it is more likely than not that some of the deferred tax assets will not be realized, the tax asset is reduced by a valuation allowance. The Company recognizes a tax benefit from an uncertain tax position when it is more likely than not that the position will be sustained upon examination, based on the technical merits of the position. The tax benefit recorded is equal to the largest amount that is greater than 50% likely to be realized through final settlement with a taxing authority. Interest and penalties related to unrecognized tax benefits are recognized in income tax expense (benefit). See Note 19—Income Taxes.
	Share-Based Compensation  The Company accounts for share-based compensation at fair value. The Company grants equity-classified awards including stock options and non-vested equity shares (restricted stock awards and units). The Company may also grant equity-classified and liability-classified awards based on a comparison of the Company’s total shareholder return (TSR) to the TSR of a predetermined group of peer companies (performance units).
	The fair value of stock option awards is determined using the Black-Scholes option-pricing model. Restricted stock awards and units are valued using the market price of Anadarko common stock. For other share-based compensation awards, fair value is determined using a Monte Carlo simulation or discounted-cash-flow methodology.
	The Company records compensation cost, net of estimated forfeitures, for share-based compensation awards over the requisite service period using the straight-line method. An adjustment is made to compensation cost for any difference between the estimated forfeitures and the actual forfeitures related to the awards. For equity-classified share-based compensation awards, expense is recognized based on the grant-date fair value. For liability-classified share-based compensation awards, expense is recognized for those awards expected to ultimately be paid. The amount of expense reported is adjusted for fair-value changes so that the expense recognized for each award is equivalent to the amount to be paid. See Note 15—Share-Based Compensation.
	Earnings Per Share  The Company’s basic earnings per share (EPS) is computed based on the average number of shares of common stock outstanding for the period and includes the effect of any participating securities as appropriate. Diluted EPS includes the effect of the Company’s outstanding stock options, restricted stock awards, restricted stock units, and performance-based stock awards, if the inclusion of these items is dilutive. See Note 13—Stockholders’ Equity.

Acquisitions_Divestitures_and_

Acquisitions, Divestitures, and Assets Held for Sale	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Acquisitions and Divestitures	'
	2. Acquisitions, Divestitures, and Assets Held for Sale
	Acquisitions  The following summarizes acquisitions made during 2013 and 2011. There were no acquisitions made during 2012.
	millions, except percentages		Percentage		Cash Paid
			Acquired
	2013
	Certain oil and gas properties and related assets in the Moxa area of Wyoming		100	%	$	310	(1)
	Gas-gathering systems in the Marcellus shale in north-central Pennsylvania		33.75	%	135
	Joint venture formed to design, construct, and own two fractionators located in		25	%	78
	Mont Belvieu, Texas
	Intrastate pipeline in southwestern Wyoming		100	%	28
	2011
	Natural-gas processing plant and related gathering systems in northeast Colorado		100	%	302
	Natural-gas processing plant (Wattenberg Plant) in northeast Colorado		93	%	500		(2)
	__________________________________________________________________
	-1	Includes $306 million that represents the fair value of the oil and gas properties acquired.
	(2)	The Company recognized a $76 million loss on preexisting contracts with the previous Wattenberg Plant owner in addition to the cash paid in the Wattenberg Plant acquisition. Anadarko operates and owns a 100% interest in the Wattenberg Plant.
	Divestitures  In 2013, sale proceeds of $509 million were primarily related to the Company’s divestiture of its interests in a soda ash joint venture and certain U.S. onshore and Indonesian oil and gas properties. Net gains of $234 million were primarily related to the Company’s divestiture of its interests in the soda ash joint venture and certain U.S. oil and gas properties.
	In 2012, sale proceeds of $433 million were primarily related to U.S. oil and gas properties and net losses of $43 million were primarily related to Indonesian oil and gas properties. In 2011, the Company received $419 million related to contingent consideration received for the 2008 divestiture of its interest in the Peregrino field offshore Brazil.
	In February 2014, the Company sold a 10% working interest in Rovuma Offshore Area 1 in Mozambique for $2.64 billion. Also in February 2014, the Company entered into an agreement to sell its oil and gas properties in China for $1.075 billion. The transaction is expected to close later in 2014 and is subject to preferential rights, regulatory approvals, and other customary closing conditions.
	Property Exchange  In 2013, the Company exchanged certain oil and gas properties in the Wattenberg field with a third party. The properties exchanged were measured at the Company’s historical net cost with no gain or loss recognized. Anadarko paid $106 million in cash as part of the exchange, which is included as an addition to properties and equipment on the Company’s Consolidated Statement of Cash Flows.
	2. Acquisitions, Divestitures, and Assets Held for Sale (Continued)
	Assets Held for Sale  During the fourth quarter of 2013, the Company began marketing certain domestic properties from the oil and gas exploration and production reporting segment to redirect its operating activities and capital investments to other areas. These assets were remeasured to their fair value using a market approach, resulting in a Level 2 fair-value measurement. Losses of $704 million primarily related to the sale of the Pinedale/Jonah assets in the Rockies, which closed in January 2014 for sale proceeds of $581 million. Gains and losses on assets held for sale are included in gains (losses) on divestitures and other, net in the Company’s Consolidated Statements of Income. At December 31, 2013, the Company’s Consolidated Balance Sheets included long-term assets of $616 million and long-term liabilities of $27 million associated with assets held for sale.
	In 2012, the Company recognized losses on assets held for sale of $28 million primarily related to certain oil and gas exploration and production reporting segment properties. At December 31, 2012, the balances of assets and liabilities associated with assets held for sale were not material.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Inventories	'
	3. Inventories
	The following summarizes the major classes of inventories, included in other current assets, at December 31:
	millions	2013		2012
	Crude oil	$	88	$	91
	Natural gas	43		48
	NGLs	79		37
	Total	$	210	$	176

Properties_and_Equipment

Properties and Equipment	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Properties and Equipment	'
	4. Properties and Equipment
	The following summarizes the cost of properties and equipment by segment at December 31:
	millions	2013		2012
	Oil and gas exploration and production (1)	$	61,302	$	55,180
	Midstream	7,285		6,032
	Marketing	9		9
	Other	2,648		2,377
	Total	$	71,244	$	63,598
	__________________________________________________________________
	(1)	Includes costs associated with unproved properties of $6.9 billion at December 31, 2013, and $7.1 billion at December 31, 2012.

Impairments

Impairments	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Impairments	'
	5. Impairments
	The following summarizes impairments by segment for the years ended December 31:
	millions	2013			2012			2011
	Oil and gas exploration and production
	Long-lived assets held for use
	U.S. onshore properties	$	142		$	259		$	1,063
	Gulf of Mexico properties	562			104			162
	Cost-method investment	11			13			91
	Midstream
	Long-lived assets held for use	79			13			458
	Impairments	$	794		$	389		$	1,774
	In 2013, certain Gulf of Mexico properties were impaired due to a reduction in estimated future net cash flows per barrel and downward revisions of reserves that the Company no longer plans to develop. Also in 2013, certain U.S. onshore properties and related midstream assets were impaired due to downward revisions of reserves that the Company no longer plans to develop. In addition, a midstream property was impaired during 2013 due to a reduction in estimated future cash flows. In 2012, certain U.S. onshore and midstream properties were impaired primarily due to lower natural-gas prices and Gulf of Mexico properties were impaired primarily as a result of downward reserves revisions for a property that was near the end of its economic life. In 2011, certain U.S. onshore and midstream properties were impaired primarily due to decreases in natural-gas prices, and Gulf of Mexico properties were impaired due to declines in estimated recoverable reserves. Impairments of the Company’s Venezuelan cost-method investment were due to declines in estimated recoverable value.
	The following summarizes the post-impairment fair value of the above-described assets, all of which were measured using the income approach and Level 3 inputs:
	millions		2013			2012
	Long-lived assets held for use		$	548		$	103
	Cost-method investment (1)		32			34
	__________________________________________________________________
	(1)	This represents the Company’s after-tax net investment.
	Impairments of Unproved Properties  Impairments of unproved properties are included in exploration expense in the Company’s Consolidated Statements of Income. In 2012, the Company recognized a $721 million impairment of unproved Powder River coalbed methane properties primarily due to lower natural-gas prices. Also in 2012, the Company recognized a $124 million impairment of an unproved Gulf of Mexico natural-gas property that the Company does not expect to develop under the forecasted natural-gas price environment.

Suspended_Exploratory_Well_Cos

Suspended Exploratory Well Costs	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Suspended Exploratory Well Costs	'
	6. Suspended Exploratory Well Costs
	The following summarizes the changes in suspended exploratory well costs at December 31 for each of the last three years. Additions pending the determination of proved reserves excludes amounts capitalized and subsequently charged to expense within the same year.
	millions	2013			2012			2011
	Balance at January 1	$	2,062		$	1,353		$	935
	Additions pending the determination of proved reserves	848			960			572
	Divestitures	(48		)	—			—
	Reclassifications to proved properties	(507		)	(129		)	(116		)
	Charges to exploration expense	(123		)	(122		)	(38		)
	Balance at December 31	$	2,232		$	2,062		$	1,353
	The following summarizes an aging of suspended exploratory well costs by geographic area and the year the costs were suspended at December 31, 2013:
					Year Costs Incurred
	millions	Total			2013(1)			2012			2011		2010 and
													prior
	United States—Onshore	$	160		$	143		$	6		$	1	$	10
	United States—Offshore	461			126			137			24		174
	International	1,611			442			526			303		340
		$	2,232		$	711		$	669		$	328	$	524
	__________________________________________________________________
	(1)	Excludes additions subsequently reclassified to proved properties within the same year.
	Suspended exploratory well costs capitalized for a period greater than one year after completion of drilling were associated with 14 projects at December 31, 2013, primarily located in Mozambique, Brazil, the Gulf of Mexico, and Ghana. Project costs suspended for longer than one year were primarily suspended pending the completion of economic evaluations including, but not limited to, results of additional appraisal drilling, well-test analysis, additional geological and geophysical data, facilities and infrastructure development options, development plan approval, and permitting. Management believes projects with suspended exploratory well costs exhibit sufficient quantities of hydrocarbons to justify potential development and is actively pursuing efforts to assess whether reserves can be attributed to these projects. If additional information becomes available that raises substantial doubt as to the economic or operational viability of any of these projects, the associated costs will be expensed at that time.

Asset_Retirement_Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Asset Retirement Obligations	'
	7. Asset Retirement Obligations
	The majority of Anadarko’s AROs relate to the plugging of wells and the related abandonment of oil and gas properties. Revisions in estimated liabilities during the period relate primarily to changes in estimates of asset retirement costs and include, but are not limited to, revisions of estimated inflation rates, changes in property lives, and the expected timing of settlement. The following summarizes changes in the Company’s AROs during 2013 and 2012:
	millions	2013			2012
	Carrying amount of asset retirement obligations at January 1	$	1,885		$	1,768
	Liabilities incurred	182			70
	Property dispositions	(76		)	(78		)
	Liabilities settled	(162		)	(89		)
	Accretion expense	110			110
	Revisions in estimated liabilities	83			104
	Carrying amount of asset retirement obligations at December 31	$	2,022		$	1,885

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Goodwill and Intangible Assets Disclosure	'
	8. Goodwill and Other Intangible Assets
	Goodwill  The Company completed its annual impairment assessment of goodwill during the fourth quarter of 2013, and the test indicated no impairment. At December 31, 2013, the Company had $5.5 billion of goodwill allocated to the following reporting units: $5.3 billion to oil and gas exploration and production, $70 million to other gathering and processing, $100 million to WES gathering and processing, and $5 million to transportation.
	Significant declines in commodity prices, difficulty or potential delays in obtaining drilling permits, or other unanticipated events could result in further goodwill impairment tests in the near term, the results of which may have a material adverse impact on the Company’s results of operations.
	Other Intangible Assets  Intangible assets and associated amortization expense were as follows:
	millions	Gross Carrying		Accumulated			Net Carrying		Amortization
		Amount		Amortization			Amount		Expense
	December 31, 2013
	Offshore platform leases	$	60	$	(50	)	$	10	$	3
	Customer contracts	169		(9		)	160		4
		$	229	$	(59	)	$	170	$	7
	December 31, 2012
	Offshore platform leases	$	60	$	(36	)	$	24	$	3
	Customer contracts	169		(5		)	164		3
		$	229	$	(41	)	$	188	$	6
	Customer contract intangible assets are primarily related to the 2011 Wattenberg Plant acquisition. The contracts are included in the Company’s midstream reporting segment and are being amortized over 50 years. The estimated aggregate amortization expense for intangible assets for the next five years is not expected to be material.

Noncontrolling_Interests

Noncontrolling Interests	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Noncontrolling Interests	'
	9. Noncontrolling Interests
	In December 2012, Western Gas Equity Partners, LP (WGP), a publicly traded consolidated subsidiary formed to own substantially all of Anadarko’s partnership interests in WES, completed its initial public offering (IPO) of approximately 20 million common units representing limited partner interests in WGP at a price of $22.00 per common unit, for net proceeds of $411 million. At December 31, 2013, Anadarko’s ownership interest in WGP consisted of a 91.0% limited partner interest and the entire non-economic general partner interest. The remaining limited partner interest in WGP consisted of a 9.0% public ownership interest.
	WES, a publicly traded consolidated subsidiary, is a limited partnership formed by Anadarko to own, operate, acquire, and develop midstream assets. WES issued approximately 12 million common units to the public raising net proceeds of $725 million in 2013, approximately 5 million common units to the public raising net proceeds of $212 million in 2012, and approximately 10 million common units to the public raising net proceeds of $328 million in 2011. At December 31, 2013, WGP’s ownership interest in WES consisted of a 41.2% limited partner interest, the entire 2.0% general partner interest, and all WES incentive distribution rights. At December 31, 2013, Anadarko also owned a 0.4% limited partner interest in WES through another subsidiary. The remaining limited partner interest in WES consisted of a 56.4% public ownership interest.

EquityMethod_Investments

Equity-Method Investments	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Equity-Method Investments	'
	10. Equity-Method Investments
	In 2007, Anadarko contributed certain of its oil and gas properties and gathering and processing assets, with an aggregate fair value of $2.9 billion at the time of the contribution, to newly formed unconsolidated entities in exchange for noncontrolling mandatorily redeemable London Interbank Offered Rate (LIBOR) based preferred interests in those entities. The common equity of the investee entities is 95% owned by third parties that also maintain control over the assets. Subsequent to their formation, the investee entities loaned Anadarko an aggregate of $2.9 billion. The Company accounts for its investment in these entities using the equity method of accounting. The carrying amount of these investments was $2.8 billion and the carrying amount of notes payable to affiliates was $2.9 billion at December 31, 2013. Anadarko has legal right of setoff and intends to net settle its obligations under each of the notes payable to the investees with the distributable value of its interest in the corresponding investee. Accordingly, the investments and the obligations are presented net on the Consolidated Balance Sheets in other long-term liabilities—other for all periods presented.
	Interest on the notes issued by Anadarko is variable, based on LIBOR, plus a spread that fluctuates with Anadarko’s credit rating. The applicable interest rate was 1.24% at December 31, 2013, and 1.31% at December 31, 2012. The note payable agreement contains a covenant that provides for a maximum Anadarko debt-to-capital ratio of 67%. Anadarko was in compliance with this covenant at December 31, 2013. Other (income) expense, net includes interest expense on the notes payable of $37 million in 2013, $42 million in 2012, and $38 million in 2011, and equity earnings from Anadarko’s investments in the investee entities of $(42) million in 2013, $(43) million in 2012, and $(41) million in 2011.

Derivative_Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Derivative Instruments	'
	11. Derivative Instruments
	Objective and Strategy  The Company uses derivative instruments to manage its exposure to cash-flow variability from commodity-price and interest-rate risks. Futures, swaps, and options are used to manage exposure to commodity-price risk inherent in the Company’s oil and natural-gas production and natural-gas processing operations (Oil and Natural-Gas Production/Processing Derivative Activities). Futures contracts and commodity-price swap agreements are used to fix the price of expected future oil and natural-gas sales at major industry trading locations, such as Henry Hub, Louisiana for natural gas and Cushing, Oklahoma or Sullom Voe, Scotland for oil. Basis swaps are periodically used to fix or float the price differential between product prices at one market location versus another. Options are used to establish a floor price, a ceiling price, or a floor and a ceiling price (collar) for expected future oil and natural-gas sales. Derivative instruments are also used to manage commodity-price risk inherent in customer price requirements and to fix margins on the future sale of natural gas and NGLs from the Company’s leased storage facilities (Marketing and Trading Derivative Activities).
	Interest-rate swaps are used to fix or float interest rates on existing or anticipated indebtedness. The purpose of these instruments is to manage the Company’s existing or anticipated exposure to unfavorable interest-rate changes. The fair value of the Company’s interest-rate swap portfolio increases (decreases) when interest rates increase (decrease).
	The Company does not apply hedge accounting to any of its derivative instruments. As a result, gains and losses associated with derivative instruments are recognized currently in earnings. Net derivative losses attributable to derivatives previously subject to hedge accounting reside in accumulated other comprehensive income (loss) and are reclassified to earnings as the transactions to which the derivatives relate are recognized in earnings. See Note 14—Accumulated Other Comprehensive Income (Loss).
	11. Derivative Instruments (Continued)
	Oil and Natural-Gas Production/Processing Derivative Activities  The natural-gas prices listed below are New York Mercantile Exchange (NYMEX) Henry Hub prices. The crude-oil prices listed below are a combination of NYMEX West Texas Intermediate and IntercontinentalExchange, Inc. (ICE) Brent Blend prices. The following is a summary of the Company’s derivative instruments related to its Oil and Natural-Gas Production/Processing Activities at December 31, 2013:
			2014				2015
			Settlement				Settlement
	Natural Gas
	Three-Way Collars (thousand MMBtu/d)		600				635
	Average price per MMBtu
	Ceiling sold price (call)		$	5.01			$	4.76
	Floor purchased price (put)		$	3.75			$	3.75
	Floor sold price (put)		$	2.75			$	2.75
	Fixed-Price Contracts (thousand MMBtu/d)		600				—
	Average price per MMBtu		$	4.26			$	—
	Extendable Fixed-Price Contracts (thousand MMBtu/d) (1)		400				—
	Average price per MMBtu		$	4.19			$	—
	Crude Oil
	Fixed-Price Contracts (MBbls/d)		107				—
	Average price per barrel		$	100.58			$	—
	__________________________________________________________________
	-1	The extendable fixed-price contracts have a contract term of January 2014 to June 2014 with an option to extend the contract term to December 2014 at the same price.
	MMBtu—million British thermal units
	MMBtu/d—million British thermal units per day
	MBbls/d—thousand barrels per day
	A three-way collar is a combination of three options: a sold call, a purchased put, and a sold put. The sold call establishes the maximum price that the Company will receive for the contracted commodity volumes. The purchased put establishes the minimum price that the Company will receive for the contracted volumes unless the market price for the commodity falls below the sold put strike price, at which point the minimum price equals the reference price (e.g., NYMEX) plus the excess of the purchased put strike price over the sold put strike price.
	Marketing and Trading Derivative Activities  The Company had financial derivative transactions with notional volumes totaling 16 billion cubic feet (Bcf) of natural gas at December 31, 2013, and 22 Bcf at December 31, 2012, that were entered into to mitigate commodity-price risk related to fixed-price purchase and sales contracts and storage activity.
	11. Derivative Instruments (Continued)
	Interest-Rate Derivatives  In December 2008 and January 2009, Anadarko entered into interest-rate swap contracts as a fixed-rate payer to mitigate the interest-rate risk associated with anticipated future debt issuances. The Company locked in a fixed interest rate in exchange for a floating interest rate indexed to the three-month LIBOR. The swap instruments include a provision that requires both the termination of the swaps and cash settlement in full at the start of the reference period.
	To align the swap portfolio with the anticipated debt refinancing, the Company extended the maturity dates for certain interest-rate swaps. In 2012, the Company extended the maturity dates from October 2012 to September 2016 for interest-rate swaps with an aggregate notional principal amount of $800 million. In 2011, the Company extended the maturity dates from October 2011 to June 2014 for interest-rate swaps with an aggregate notional principal amount of $1.85 billion. In connection with these extensions, the swap interest rates were also adjusted. Interest-rate swap agreements with an aggregate notional principal amount of $200 million were settled in October 2012, resulting in a payment of $64 million, and interest-rate swap agreements with an aggregate notional principal amount of $150 million were settled in October 2011, resulting in a payment of $57 million.
	The Company had the following outstanding interest-rate swaps at December 31, 2013:
	millions except percentages					Reference Period				Weighted-Average
	Notional Principal Amount					Start		End		Interest Rate
	$	750				Jun-14		Jun-24		6.00%
	$	1,100				Jun-14		Jun-44		5.57%
	$	50				Sep-16		Sep-26		5.91%
	$	750				Sep-16		Sep-46		5.86%
	Effect of Derivative Instruments—Balance Sheet The following summarizes the fair value of the Company’s derivative instruments at December 31:
	millions		Gross								Gross
			Derivative Assets								Derivative Liabilities
	Balance Sheet Classification		2013				2012				2013				2012
	Commodity derivatives
	Other current assets		$	181			$	475			$	(102	)		$	(197	)
	Other assets		89				24				(66		)		(7		)
	Accrued expenses		106				6				(149		)		(14		)
	Other liabilities		4				1				(15		)		(7		)
			380				506				(332		)		(225		)
	Interest-rate and other derivatives
	Accrued expenses (1)		—				—				(480		)		—
	Other liabilities (1)		—				—				(174		)		(1,194		)
			—				—				(654		)		(1,194		)
	Total derivatives		$	380			$	506			$	(986	)		$	(1,419	)
	__________________________________________________________________
	(1)	Interest-rate swaps with June 2014 maturity dates were reclassified from other liabilities to accrued expenses during 2013.
	11. Derivative Instruments (Continued)
	Effect of Derivative Instruments—Statement of Income  The following summarizes gains and losses related to derivative instruments:
	millions
	Classification of (Gain) Loss Recognized		2013				2012				2011
	Commodity derivatives
	Gathering, processing, and marketing sales (1)		$	6			$	18			$	8
	(Gains) losses on derivatives, net		141				(387		)		(562		)
	Interest-rate and other derivatives
(Gains) losses on derivatives, net		(539		)		61				1,023
Total (gains) losses on derivatives, net		$	(392	)		$	(308	)		$	469
__________________________________________________________________
(1)	Represents the effect of marketing and trading derivative activities.
Credit-Risk Considerations  The financial integrity of exchange-traded contracts, which are subject to nominal credit risk, is assured by NYMEX or ICE through systems of financial safeguards and transaction guarantees. Over-the-counter traded swaps, options, and futures contracts expose the Company to counterparty credit risk. The Company monitors the creditworthiness of its counterparties, establishes credit limits according to the Company’s credit policies and guidelines, and assesses the impact on fair value of its counterparties’ creditworthiness. The Company has the ability to require cash collateral or letters of credit to mitigate its credit-risk exposure. The Company has netting agreements with financial institutions that permit net settlement of gross commodity derivative assets against gross commodity derivative liabilities, and routinely exercises its contractual right to offset gains and losses when settling with derivative counterparties.
In addition, the Company has setoff agreements with certain financial institutions that may be exercised in the event of default and that provide for contract termination and net settlement across derivative types. At December 31, 2013, $76 million of the Company’s $986 million gross derivative liability balance, and at December 31, 2012, $339 million of the Company’s $1.4 billion gross derivative liability balance would have been eligible for setoff against the Company’s gross derivative asset balance in the event of default. Other than in the event of default, the Company does not net settle across derivative types.
Some of the Company’s derivative instruments are subject to provisions that can require full or partial collateralization or immediate settlement of the Company’s obligations if certain credit-risk-related provisions are triggered. However, most of the Company’s derivative counterparties maintain secured positions with respect to the Company’s derivative liabilities under the Company’s $5.0 billion senior secured revolving credit facility maturing in September 2015 ($5.0 billion Facility).
Unsecured derivative obligations may require immediate settlement or full collateralization if certain credit-risk-related provisions are triggered, such as the Company’s credit rating from major credit rating agencies declining to a level below investment grade. The aggregate fair value of derivative instruments with credit-risk-related contingent features for which a net liability position existed was $42 million (net of collateral) at December 31, 2013, and $94 million (net of collateral) at December 31, 2012. The current portion of these amounts was included in accrued expenses and the long-term portion of these amounts was included in other long-term liabilities—other on the Company’s Consolidated Balance Sheets.
11. Derivative Instruments (Continued)
Fair Value  Fair value of futures contracts is based on quoted prices in active markets for identical assets or liabilities, which represent Level 1 inputs. Valuations of physical-delivery purchase and sale agreements, over-the-counter financial swaps, and commodity option collars are based on similar transactions observable in active markets and industry-standard models that primarily rely on market-observable inputs. Inputs used to estimate the fair value of swaps and options include market-price curves; contract terms and prices; credit-risk adjustments; and, for Black-Scholes option valuations, implied market volatility and discount factors. Inputs used to estimate fair value in industry-standard models are categorized as Level 2 inputs because substantially all assumptions and inputs are observable in active markets throughout the full term of the instruments.
The following summarizes the fair value of the Company’s derivative assets and liabilities, by input level within the fair-value hierarchy:
millions	Level 1				Level 2				Level 3				Netting (1)				Collateral		Total
December 31, 2013
Assets
Commodity derivatives
Financial institutions	$	—			$	211			$	—			$	(153	)		$	—	$	58
Other counterparties	—				169				—				(126		)		—		43
Total derivative assets	$	—			$	380			$	—			$	(279	)		$	—	$	101
Liabilities
Commodity derivatives
Financial institutions	$	—			$	(200	)		$	—			$	153			$	7	$	(40	)
Other counterparties	—				(132		)		—				126				—		(6		)
Interest-rate and other derivatives	—				(654		)		—				—				—		(654		)
Total derivative liabilities	$	—			$	(986	)		$	—			$	279			$	7	$	(700	)
December 31, 2012
Assets
Commodity derivatives
Financial institutions	$	6			$	453			$	—			$	(206	)		$	—	$	253
Other counterparties	—				47				—				(5		)		—		42
Total derivative assets	$	6			$	500			$	—			$	(211	)		$	—	$	295
Liabilities
Commodity derivatives
Financial institutions	$	(6	)		$	(202	)		$	—			$	206			$	1	$	(1	)
Other counterparties	—				(17		)		—				5				—		(12		)
Interest-rate and other derivatives	—				(1,194		)		—				—				—		(1,194		)
Total derivative liabilities	$	(6	)		$	(1,413	)		$	—			$	211			$	1	$	(1,207	)
__________________________________________________________________
(1)	Represents the impact of netting commodity derivative assets and liabilities with counterparties where the Company has the contractual right and intends to net settle.

Debt_and_Interest_Expense

Debt and Interest Expense	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Debt and Interest Expense	'
	12. Debt and Interest Expense
	Debt  The Company’s outstanding debt is senior unsecured, except for borrowings, if any, under the $5.0 billion Facility. See Note 10—Equity-Method Investments for disclosure regarding Anadarko’s notes payable related to its ownership of certain noncontrolling mandatorily redeemable interests that are not included in the Company’s reported debt balance and do not affect consolidated interest expense. The following summarizes the Company’s outstanding debt:
		December 31,
	millions	2013			2012
	5.750% Senior Notes due 2014	$	275		$	275
	7.625% Senior Notes due 2014	500			500
	5.950% Senior Notes due 2016	1,750			1,750
	6.375% Senior Notes due 2017	2,000			2,000
	7.050% Debentures due 2018	114			114
	WES 2.600% Senior Notes due 2018	250			—
	6.950% Senior Notes due 2019	300			300
	8.700% Senior Notes due 2019	600			600
	WES 5.375% Senior Notes due 2021	500			500
	WES 4.000% Senior Notes due 2022	670			670
	6.950% Senior Notes due 2024	650			650
	7.500% Debentures due 2026	112			112
	7.000% Debentures due 2027	54			54
	7.125% Debentures due 2027	150			150
	6.625% Debentures due 2028	17			17
	7.150% Debentures due 2028	235			235
	7.200% Debentures due 2029	135			135
	7.950% Debentures due 2029	117			117
	7.500% Senior Notes due 2031	900			900
	7.875% Senior Notes due 2031	500			500
	Zero-Coupon Senior Notes due 2036	2,360			2,360
	6.450% Senior Notes due 2036	1,750			1,750
	7.950% Senior Notes due 2039	325			325
	6.200% Senior Notes due 2040	750			750
	7.730% Debentures due 2096	61			61
	7.500% Debentures due 2096	78			78
	7.250% Debentures due 2096	49			49
	Total debt at face value	$	15,202		$	14,952
	Net unamortized discounts and premiums (1)	(1,645		)	(1,683		)
	Total borrowings	$	13,557		$	13,269
	Capital lease obligation	8			—
	Less current portion of long-term debt	500			—
	Total long-term debt	$	13,065		$	13,269
	__________________________________________________________________
	(1)	Unamortized discounts and premiums are amortized over the term of the related debt.
	12. Debt and Interest Expense (Continued)
	In a 2006 private offering, Anadarko received $500 million of loan proceeds upon issuing the Zero-Coupon Senior Notes due 2036 (Zero Coupons). The Zero Coupons mature in 2036 and have an aggregate principal amount due at maturity of $2.4 billion, reflecting a yield to maturity of 5.24%. The Zero Coupons can be put to the Company in October of each year, which would cause the Company to repay up to the then-accreted value of the outstanding Zero Coupons. The accreted value of the outstanding Zero Coupons was $727 million at December 31, 2013. Anadarko’s $275 million aggregate principal amount of 5.750% Senior Notes due June 2014 and Zero Coupons, which can be put to the Company in 2014, are classified as long-term debt on the Company’s Consolidated Balance Sheets, as the Company has the ability and intent to refinance these obligations using long-term debt.
	Fair Value  The Company uses a market approach to determine the fair value of its fixed-rate debt using observable market data, which results in a Level 2 fair-value measurement. The carrying amount of floating-rate debt approximates fair value as the interest rates are variable and reflective of market rates. The estimated fair value of the Company’s total borrowings was $15.3 billion at December 31, 2013, and $16.2 billion at December 31, 2012.
	Debt Activity  The following summarizes the Company’s debt activity during 2013 and 2012:
	millions	Carrying			Description
		Value
	Balance at December 31, 2011	$	15,230
	Issuances	674			WES 4.000% Senior Notes due 2022
	Borrowings	374			WES revolving credit facility
	Repayments	(131		)	6.125% Senior Notes due 2012
		(39		)	5.000% Senior Notes due 2012
		(374		)	WES revolving credit facility
		(2,500		)	$5.0 billion Facility
	Other, net	35			Amortization of debt discounts and premiums
	Balance at December 31, 2012	$	13,269
	Issuances	250			WES 2.600% Senior Notes due 2018
	Borrowings	710			WES revolving credit facility
	Repayments	(710		)	WES revolving credit facility
	Other, net	38			Amortization of debt discounts and premiums
	Balance at December 31, 2013	$	13,557
	12. Debt and Interest Expense (Continued)
	Anadarko Revolving Credit Facility and Letter of Credit Facility  In September 2010, the Company entered into the $5.0 billion Facility maturing in September 2015. Borrowings under the $5.0 billion Facility bear interest at LIBOR plus an applicable margin ranging from 1.25% to 2.50%, depending on the Company’s credit rating, or rates at a margin above the one-month LIBOR, the federal funds rate, or prime rates offered by certain designated banks. During 2012, the Company repaid all outstanding borrowings under the $5.0 billion Facility with cash on hand and cash realized from the resolution of the Algeria exceptional profits tax dispute.
	Obligations incurred under the $5.0 billion Facility, as well as obligations Anadarko has to lenders or their affiliates pursuant to certain derivative instruments that are supported by the $5.0 billion Facility (as discussed in Note 11—Derivative Instruments), are guaranteed by certain of the Company’s wholly owned domestic subsidiaries, and are secured by a perfected first-priority security interest in certain exploration and production assets located in the United States and 65% of the capital stock of certain wholly owned foreign subsidiaries. At December 31, 2013, the Company was in compliance with applicable covenants and there were no restrictions on its ability to utilize the $5.0 billion Facility.
	WES Borrowings  In March 2011, WES entered into a five-year, $800 million senior unsecured revolving credit facility maturing in March 2016 (RCF). Borrowings under the RCF bear interest at LIBOR plus an applicable margin ranging from 1.30% to 1.90%, or rates at a margin above the one-month LIBOR, the federal funds rate, or prime rates offered by certain designated banks. During 2013, WES repaid all outstanding borrowings under its RCF with proceeds from debt and equity offerings. At December 31, 2013, WES was in compliance with all covenants contained in its RCF.
In February 2014, WES entered into a five-year, $1.2 billion senior unsecured revolving credit facility maturing in February 2019 (2014 RCF), which amended and restated the RCF. The 2014 RCF is expandable to a maximum of $1.5 billion. Borrowings under the 2014 RCF bear interest at LIBOR plus an applicable margin ranging from 0.975% to 1.45%, or rates at a margin above the one-month LIBOR, the federal funds rate, or prime rates offered by certain designated banks.
Scheduled Maturities  Total principal amount of debt maturities for the five years ending December 31, 2018, excluding the potential repayment of the outstanding Zero Coupons that may be put by the holder to the Company annually, were as follows:
millions	Principal
	Amount of
	Debt Maturities
2014	$	775
2015	—
2016	1,750
2017	2,000
2018	364
Interest Expense  The following summarizes interest expense for the years ended December 31:
millions	2013			2012			2011
Current debt, long-term debt, and other	$	949		$	963		$	986
Capitalized interest	(263		)	(221		)	(147		)
Interest expense	$	686		$	742		$	839

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Stockholders' Equity	'
	13. Stockholders’ Equity
	Common Stock  The following summarizes the changes in the Company’s outstanding shares of common stock:
	millions	2013		2012			2011
	Shares of common stock issued
	Shares at January 1	519		516			513
	Exercise of stock options	2		1			1
	Issuance of restricted stock	2		2			2
	Shares at December 31	523		519			516
	Shares of common stock held in treasury
	Shares at January 1	18		18			17
	Shares received for restricted stock vested and options exercised	1		—			1
	Shares at December 31	19		18			18
	Shares of common stock outstanding at December 31	504		501			498
	The following provides a reconciliation between basic and diluted EPS attributable to common stockholders for the years ended December 31:
	millions except per-share amounts	2013			2012			2011
	Net income (loss)
	Net income (loss) attributable to common stockholders	$	801		$	2,391		$	(2,649	)
	Less distributions on participating securities	2			1			—
	Less undistributed income allocated to participating securities	4			14			—
	Basic	$	795		$	2,376		$	(2,649	)
	Diluted	$	795		$	2,376		$	(2,649	)
	Shares
	Average number of common shares outstanding—basic	502			500			498
	Dilutive effect of stock options	3			2			—
	Average number of common shares outstanding—diluted	505			502			498
	Excluded (1)	4			6			12
	Net income (loss) per common share
	Basic	$	1.58		$	4.76		$	(5.32	)
	Diluted	$	1.58		$	4.74		$	(5.32	)
	Dividends per common share	$	0.54		$	0.36		$	0.36
	__________________________________________________________________
	(1)	Inclusion of certain shares would have had an anti-dilutive effect.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Accumulated Other Comprehensive Income (Loss)	'
	14. Accumulated Other Comprehensive Income (Loss)
	The following summarizes the after-tax changes in the balances of each component of accumulated other comprehensive income (loss):
	millions	Interest-rate			Pension and Other Postretirement			Total
		Derivatives			Plans
		Previously
		Subject to Hedge
		Accounting
	Balance at December 31, 2012	$	(61	)	$	(579	)	$	(640	)
	Other comprehensive income (loss), before	—			264			264
	reclassifications
	Reclassifications to Consolidated Statement of Income	7			84			91
	Net other comprehensive income (loss)	7			348			355
	Balance at December 31, 2013	$	(54	)	$	(231	)	$	(285	)

ShareBased_Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Share-Based Compensation	'
	15. Share-Based Compensation
	At December 31, 2013, 26 million shares of the 31 million shares of Anadarko common stock originally authorized for awards under active share-based compensation plans remained available for future issuance. The Company generally issues new shares to satisfy awards under employee share-based payment plans. The number of shares available is reduced by awards granted. The following summarizes share-based compensation expense for the years ended December 31:
	millions	2013				2012				2011
	Equity-Classified Awards
	Restricted stock	$	122			$	103			$	80
	Stock options	27				43				51
	Performance-based share awards and other	1				1				1
	Total equity-classified award compensation expense	150				147				132
	Liability-Classified Awards
	Value creation plan	—				(2		)		26
	Performance-based unit awards	4				8				28
	Other performance-based awards	—				165				28
	Other	1				2				1
	Total liability-classified award compensation expense	5				173				83
	Pretax compensation expense	$	155			$	320			$	215
	Income tax benefit	$	57			$	117			$	78
	Cash flows from financing activities included excess tax benefits related to share-based compensation of $11 million in 2013, $51 million in 2012, and $(15) million in 2011. Cash received from stock option exercises was $135 million in 2013, $52 million in 2012, and $45 million in 2011.
	15. Share-Based Compensation (Continued)
	Equity-Classified Awards
	Restricted Stock  Certain employees may be granted restricted stock in the form of restricted stock awards or restricted stock units. Restricted stock is subject to forfeiture restrictions and cannot be sold, transferred, or disposed of during the restriction period. The holders of restricted stock awards have the same rights as a stockholder of the Company with respect to such shares, including the right to vote and receive dividends or other distributions paid with respect to the shares. A restricted stock unit is equivalent to a restricted stock award except that unit holders do not have the right to vote. Restricted stock vests over service periods ranging from the date of grant up to three years and is not considered issued and outstanding until vested.
	Non-employee directors are granted deferred shares, which are also considered restricted stock, that are held in a grantor trust by the Company until payable. Non-employee directors may receive these shares in a lump-sum payment or in annual installments.
	The following summarizes the Company’s restricted stock activity:
		Shares			Weighted-
		(millions)			Average
					Grant-Date
					Fair Value
					(per share)
	Non-vested at January 1, 2013	2.82			$	79.27
	Granted	1.88			$	84.17
	Vested	(1.32	)		$	78.19
	Forfeited	(0.16	)		$	80.37
	Non-vested at December 31, 2013	3.22			$	82.53
	The weighted-average grant-date fair value per share of restricted stock granted was $79.97 during 2012 and $81.19 during 2011. The total fair value of restricted shares vested was $110 million during 2013, $105 million during 2012, and $124 million during 2011, based on the market price at the vesting date. At December 31, 2013, total unrecognized compensation cost related to restricted stock of $175 million is expected to be recognized over a weighted-average remaining service period of 1.9 years.
	15. Share-Based Compensation (Continued)
	Stock Options  Certain employees may be granted nonqualified options to purchase shares of Anadarko common stock with an exercise price equal to, or greater than, the fair market value of Anadarko common stock on the date of grant. These stock options vest over three years from the date of grant and terminate at the earlier of the date of exercise or seven years from the date of grant.
	The fair value of stock option awards is determined using the Black-Scholes option-pricing model. The expected life of an option is estimated based on historical exercise behavior. Volatility assumptions are estimated based on an average of historical volatility over the expected life of an option and the 12-month average implied volatility. Risk-free interest rates are based on the U.S. Treasury rate over the expected life of an option. The dividend yield is based on a 12-month average dividend yield, taking into account the Company’s expected dividend policy over the expected life of an option. Expected forfeiture rates are estimated based on historical forfeiture experience. The Company used the following weighted-average assumptions to estimate the fair value of stock options granted during 2013, 2012, and 2011:
		2013				2012				2011
	Expected option life—years	4.8				4.9				4.8
	Volatility	33.9		%		44.2		%		42		%
	Risk-free interest rate	1.3		%		0.7		%		1.5		%
	Dividend yield	0.8		%		0.5		%		0.5		%
	The following summarizes the Company’s stock option activity:
		Shares			Weighted-				Weighted-		Aggregate
		(millions)			Average				Average		Intrinsic
					Exercise				Remaining		Value
					Price				Contractual		(millions)
					(per share)				Term
									(years)
	Outstanding at January 1, 2013	9.36			$	58.66
	Granted	0.91			$	91.71
	Exercised	(2.43	)		$	55.59
	Forfeited or expired	(0.12	)		$	74.55
	Outstanding at December 31, 2013	7.72			$	63.3			3.59		$	138.3
	Vested or expected to vest at December 31, 2013	7.65			$	63.14			3.57		$	138.2
	Exercisable at December 31, 2013	5.87			$	57			2.83		$	133.5
	The per-option weighted-average grant-date fair value of stock options granted was $26.27 during 2013, $25.84 during 2012, and $29.77 during 2011. The total intrinsic value of stock options exercised was $80 million during 2013, $49 million during 2012, and $45 million during 2011, based on the difference between the market price at the exercise date and the exercise price. At December 31, 2013, total unrecognized compensation cost related to stock options of $41 million is expected to be recognized over a weighted-average remaining service period of 2.2 years.
	15. Share-Based Compensation (Continued)
	Performance-Based Share Awards  In 2007, certain officers of the Company were provided Performance Unit Award Agreements with performance periods ranging from one to three years. The number of shares of common stock earned under these agreements was based on a comparison of the Company’s TSR to the TSR of a predetermined group of peer companies over the specified performance periods. The maximum number of shares of Anadarko common stock available to be earned was 934,424 shares based on predefined payout percentages. At December 31, 2013, all performance periods have ended and a total of 521,258 shares were earned, with no additional shares available to be earned in the future. Of the total shares earned, 506,449 shares have been issued and 14,809 shares have been deferred pursuant to the agreements. The fair value of the performance-based share awards issued was $11 million during 2013, zero during 2012, and $6 million during 2011, based on the market price on the date of issuance. At December 31, 2013, the Company had no unrecognized compensation cost related to these awards.
	Liability-Classified Awards
	Value Creation Plan  As a part of its employee compensation program, the Company offers an incentive compensation program that provides non-officer employees the opportunity to earn cash bonus awards based on the Company’s TSR for the year, compared to the TSR of a predetermined group of peer companies. The Company paid zero during 2013 related to the plan, $24 million during 2012, and zero during 2011. At December 31, 2013, the Company had no outstanding liability attributable to the 2013 performance period.
	Performance-Based Unit Awards  Certain officers of the Company were provided Performance Unit Award Agreements with two- and three-year performance periods. The vesting of these units is based on comparing the Company’s TSR to the TSR of a predetermined group of peer companies over the specified performance period. Each performance unit represents the value of one share of the Company’s common stock. At the end of each performance period, the value of the vested performance units, if any, is paid in cash. The Company paid $15 million related to vested performance units in 2013, $37 million in 2012, and $25 million in 2011. At December 31, 2013, the Company’s liability under Performance Unit Award Agreements was $15 million, with total unrecognized compensation cost related to these awards of $20 million expected to be recognized over a weighted-average remaining performance period of 1.9 years.
	Other Performance-Based Awards  Prior to 2011, certain officers of the general partner of WES were awarded general partner Unit Appreciation Rights (UARs) pursuant to the Western Gas Holdings, LLC Equity Incentive Plan. The fair value of the UARs was determined based on the fair value of WES’s general partner, as determined by the WGP IPO price. The Company paid $203 million related to the UARs upon the WGP IPO in 2012 in settlement of obligations related to all awards then outstanding.

Commitments

Commitments	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Commitments	'
	16. Commitments
	Operating Leases  At December 31, 2013, the Company had $3.3 billion in long-term drilling rig commitments that satisfy operating lease criteria. The Company also had $388 million of various commitments under non-cancelable operating lease agreements for production platforms and equipment, buildings, facilities, compressors, and aircraft. These operating leases expire at various dates through 2026. Certain of these operating leases contain residual value guarantees at the end of the lease term, totaling $53 million at December 31, 2013. No liability has been accrued for residual value guarantees. In addition, these operating leases include options to purchase the leased property during or at the end of the lease term for the fair market value or other specified amount at that time. The following summarizes future minimum lease payments under operating leases at December 31, 2013:
	millions
	2014	$	964
	2015	948
	2016	755
	2017	525
	2018	309
	Later years	189
	Total future minimum lease payments	$	3,690
	Total rent expense, net of sublease income, amounted to $119 million in 2013, $136 million in 2012, and $143 million in 2011. Total rent expense includes contingent rent expense related to processing fees of $17 million in 2013, $18 million in 2012, and $21 million in 2011.
	Drilling Rig Commitments  Anadarko has entered into various agreements to secure drilling rigs necessary to execute its drilling plans over the next several years. The table of future minimum lease payments above includes $3.1 billion related to eight offshore drilling vessels and $155 million related to certain contracts for U.S. onshore drilling rigs. Lease payments associated with the drilling of exploratory wells and development wells, net of amounts billed to partners, will initially be capitalized as a component of oil and gas properties, and either depreciated or impaired in future periods or written off as exploration expense.
	Spar Platform and Production Vessel Leases  Anadarko has operating leases related to certain spar platforms in the Gulf of Mexico. The table of future minimum lease payments above includes approximately $206 million for these agreements.
	Other Commitments  In the normal course of business, the Company enters into other contractual agreements for processing, treating, transportation, and storage of natural gas, crude oil, and NGLs, as well as for other oil and gas activities. These agreements expire at various dates through 2030. At December 31, 2013, aggregate future payments under these contracts totaled $11.5 billion, of which $2.3 billion is expected to be paid in 2014, $1.8 billion in 2015, $1.4 billion in 2016, $1.2 billion in 2017, $1.1 billion in 2018, and $3.7 billion thereafter.

Contingencies

Contingencies	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Contingencies	'
	17. Contingencies
	Litigation  The Company is a defendant in a number of lawsuits and is involved in governmental proceedings and regulatory controls arising in the ordinary course of business, including, but not limited to, personal injury claims; title disputes; tax disputes; royalty claims; contract claims; contamination claims relating to oil and gas production, transportation, and processing; and environmental claims, including claims involving assets owned by acquired companies and claims involving assets previously sold to third parties and no longer a part of the Company’s current operations. The Company’s Consolidated Balance Sheets include liabilities of $854 million at December 31, 2013, and $49 million at December 31, 2012, for litigation-related contingencies. Anadarko is also subject to various environmental-remediation and reclamation obligations arising from federal, state, and local laws and regulations. While the ultimate outcome and impact on the Company cannot be predicted with certainty, after consideration of recorded expense and liability accruals, management believes that, with the possible exception of the Tronox Litigation discussed below, the resolution of pending proceedings will not have a material adverse effect on the Company’s consolidated financial position, results of operations, or cash flows.
	Tronox Litigation  On November 28, 2005, Tronox Incorporated (Tronox), at the time a subsidiary of Kerr-McGee Corporation, completed an IPO and was subsequently spun-off from Kerr-McGee Corporation. In August 2006, Anadarko acquired all of the stock of Kerr-McGee Corporation. In January 2009, Tronox and certain of Tronox’s subsidiaries filed voluntary petitions for relief under Chapter 11 of the U.S. Bankruptcy Code in the U.S. Bankruptcy Court for the Southern District of New York (Bankruptcy Court), which is the court that is also hearing the Adversary Proceeding (defined below). Subsequently, in May 2009, Tronox and certain of its affiliates filed a lawsuit against Anadarko and Kerr-McGee Corporation and certain of its subsidiaries (collectively, Kerr-McGee) asserting several claims, including claims for actual and constructive fraudulent conveyance (Adversary Proceeding). Tronox alleged, among other things, that it was insolvent or undercapitalized at the date of its IPO and sought, among other things, to recover damages from Kerr-McGee and Anadarko, as well as interest, appreciation, and attorneys’ fees and costs. In accordance with Tronox’s Bankruptcy Court-approved Plan of Reorganization (Plan), the Adversary Proceeding is being pursued by a litigation trust (Litigation Trust). Pursuant to the Plan, the Litigation Trust was “deemed substituted” for the Tronox plaintiffs in the Adversary Proceeding. For purposes of this Form 10-K, references to “Tronox” after February 2011 refer to the Litigation Trust.
	The U.S. government intervened in the Adversary Proceeding, and in May 2009 asserted separate claims against Anadarko and Kerr-McGee under the Federal Debt Collection Procedures Act (FDCPA Complaint). The Litigation Trust and the U.S. government have agreed that the recovery of damages under the Adversary Proceeding, if any, would cover both the Adversary Proceeding and the FDCPA Complaint.
	In February 2011, Tronox emerged from bankruptcy pursuant to the Plan. The terms of the Plan, which were confirmed by the Bankruptcy Court in the fourth quarter of 2010, contemplate that the claims of the U.S. government (together with other federal, state, local, and tribal governmental entities having regulatory authority or responsibilities for environmental laws, collectively, the Governmental Entities) related to Tronox’s environmental liabilities and tort claims asserted against Tronox by other creditors will be settled through certain environmental response trusts and the Litigation Trust. The Plan provides for an allocation of any proceeds from the Adversary Proceeding between the Governmental Entities and the other creditors.
	In January 2012, the Bankruptcy Court held that Section 550(a) of the Bankruptcy Code does not impose a cap on potential damages Tronox may recover, stating that the appropriate measure of damages should only be determined after trial in the Adversary Proceeding.
	The Adversary Proceeding trial was held from May 2012 through September 2012. In November 2012, the parties filed post-trial briefs, and closing arguments were presented in December 2012. In December 2013, the Bankruptcy Court issued a Memorandum of Opinion, After Trial (discussed below).
	17. Contingencies (Continued)
	Historical Accounting  The Company recognized losses of $250 million in the fourth quarter of 2011 and $275 million in the first quarter of 2012, for a total estimated contingent liability related to the Adversary Proceeding of $525 million at March 31, 2012. At that time, the Company’s assessment was that it was probable the parties would reach a settlement and thus the Company considered a loss, via settlement, to be probable. The Company’s attempts during the second quarter of 2012 to resolve the Adversary Proceeding through mediation and settlement discussions reached an impasse. Accordingly, based on information available at that time, the Company’s assessment was that the likelihood of resolving the Adversary Proceeding through settlement was remote, that the likely form of final resolution of this matter was through litigation and the appellate process, and that a loss was not probable. Therefore, the Company reversed the settlement-based $525 million contingent liability in the second quarter of 2012 resulting in no accrued liability for this matter at June 30, 2012. There were no events or developments that changed the Company’s assessment until December 2013.
	Memorandum of Opinion  In December 2013, the Bankruptcy Court issued a Memorandum of Opinion, After Trial (Opinion) in which the Bankruptcy Court found Kerr-McGee liable for fraudulent transfers in connection with Kerr-McGee’s 2002 internal corporate restructuring and the subsequent IPO of Tronox. In its Opinion, the Bankruptcy Court concluded that damages from the fraudulent conveyance were equal to the value of the transferred assets as of the IPO date of $14.459 billion, but that Kerr-McGee may file a claim under Section 502(h) of the U.S. Bankruptcy Code (502(h) Claim). The Opinion provisionally outlined a framework for determining the amount of Kerr-McGee’s 502(h) Claim, resulting in a 502(h) Claim amount of $10.459 billion. The Bankruptcy Court noted that a portion of the 502(h) Claim, if allowed, would be offset against an award of damages. The Bankruptcy Court expressed its opinion that it has the authority to enter a judgment against Kerr-McGee, but did not enter a judgment against Kerr-McGee at the time of the issuance of its Opinion because it had not resolved questions it raised concerning Kerr-McGee’s 502(h) Claim and the portion of the 502(h) Claim that could be recovered (Recovery Percentage). The Bankruptcy Court also noted that attorneys’ fees and costs could be added to an award to the extent appropriate. The Bankruptcy Court ordered the parties to submit further briefing regarding Kerr-McGee’s 502(h) Claim.
	Briefing on 502(h) Claim  In accordance with the Bankruptcy Court’s order, Kerr-McGee submitted its brief and filed its 502(h) Claim in January 2014 and the plaintiffs’ response was submitted in February 2014. Kerr-McGee argued in its brief, among other things, that the Bankruptcy Court should not dilute Kerr-McGee’s 502(h) Claim and that the Bankruptcy Court, in its provisional findings, has not properly considered the amount of Kerr-McGee’s 502(h) Claim or the Recovery Percentage. Kerr-McGee argued that the proper application of the Bankruptcy Court’s findings of fact and conclusions of law would result in net damages of $850 million. Alternatively, the Company argued that using the Bankruptcy Court’s framework, damages should be limited to the net present value of the legacy environmental and tort liabilities at the IPO date, which the Bankruptcy Court determined to be $1.757 billion.
	In their responsive pleadings, the plaintiffs argued, among other things, that Kerr-McGee’s 502(h) Claim should be disallowed or, in the alternative, diluted to either 68% or 2.8% of its value. Furthermore, the plaintiffs argued that in addition to the value of the transferred assets as of the IPO date, they are entitled to recover appreciation in the value of those assets from the IPO date through June 2012, the date testimony was provided by a plaintiffs’ expert. If combined with a disallowed 502(h) Claim as argued by the plaintiffs, this would yield net damages to the plaintiffs in the amount of $18.85 billion, excluding interest and attorneys’ fees and costs. Further, the plaintiffs are seeking pre-judgment interest applied at a rate of 6% compounded annually from June 2012 through the date of judgment, which combined with the net damages amount above would total $20.77 billion as of February 2014. The plaintiffs also submitted a request to be reimbursed for $61 million in attorneys’ fees and costs.
	Kerr-McGee has until March 14, 2014, to submit a reply to the plaintiffs’ brief. The Opinion indicated that either party may request a hearing on the matters being briefed, and a hearing has been scheduled for April 2014. After this process, the Bankruptcy Court is expected to issue a judgment, which will then be subject to appeal.
	17. Contingencies (Continued)
	Liability Accrual Analysis  Applicable accounting guidance requires the Company to accrue a liability if (a) it is probable that a liability has been incurred and (b) the amount of that liability can be reasonably estimated. That guidance also requires a liability accrual at the low end of an estimated range of probable loss when no amount within the range is a better estimate than any other amount. The Company believes that a loss in the Adversary Proceeding is probable, based on the Bankruptcy Court’s finding of liability in its Opinion. The Company considers a reasonable estimate of the range of probable loss, after all appellate processes have concluded, to be $850 million to $5.15 billion, and recorded a liability of $850 million, equal to the low end of that range. Although the Company does not believe a loss in excess of $5.15 billion to be probable, it is reasonably possible that the loss could be as high as $14.52 billion, including $61 million for attorneys’ fees and costs, but excluding any potential interest and appreciation.
	The Company’s $850 million contingent liability accrual is based on the application of accounting guidance to currently available information and the Company’s judgment concerning the application of law to that information. Furthermore, the Company’s liability accrual and estimated range of probable loss do not include any amounts for interest, appreciation, or attorneys’ fees and costs, and reflects its assessment that resolution through settlement is not probable at this time. The ultimate outcome of the Adversary Proceeding is subject to significant uncertainty; accordingly, the Company’s liability accrual could change materially in the near term as events unfold and more information becomes available. In quantifying an estimated range of probable loss, the Company considered the following components of a possible award for which it could ultimately be responsible: damages, pre-judgment interest and appreciation, post-judgment interest, and attorneys’ fees and costs.
	Damages  The Company estimates a range of probable damages ultimately awarded to the plaintiffs to be $850 million to $5.15 billion. This estimate is based on currently available information and the Company’s opinion regarding the ultimate outcome of the Adversary Proceeding. As described below, the degree of uncertainty regarding the determination of Kerr-McGee’s allowable 502(h) Claim and the Recovery Percentage prevents the Company from determining any one amount within the estimated range of probable loss to be a better estimate than any other amount.
	Critical factors in assessing the estimated range of probable loss with respect to damages are the as-yet unresolved issues of the amount of Kerr-McGee’s 502(h) Claim, and the extent to which such an offset amount would reduce damages. The Bankruptcy Court provisionally stated that the 502(h) Claim could be $10.459 billion. This 502(h) Claim amount represents the difference between (i) $14.459 billion, which is the Bankruptcy Court’s finding as to damages based on the net value of the transferred assets as of the date of IPO, and (ii) $4.0 billion, which is the mid-point in the plaintiffs’ post-petition estimate of potential legacy environmental and tort liabilities as of 2010. To calculate the offset amount that could reduce damages, the Bankruptcy Court indicated that the Recovery Percentage to be applied to Kerr-McGee’s 502(h) Claim could be either 89% or 2.8%. The Bankruptcy Court noted in its Opinion that the Plan provides that Kerr-McGee’s 502(h) Claim must be multiplied by “the percentage recovery to Allowed Class 3 General Unsecured Creditors” (Class 3 Recovery). Additionally, the Bankruptcy Court noted that 89% represents the estimated average Class 3 Recovery as stated in the Disclosure Statement filed by Tronox in its bankruptcy case. Under this scenario, the damages paid to the plaintiffs would be reduced by approximately $9.3 billion, resulting in a net damage award to plaintiffs of $5.15 billion.
	The Bankruptcy Court also suggested that the Recovery Percentage might be determined after including Kerr-McGee’s 502(h) Claim with the Class 3 claims allowed under the Plan, which would have the effect of diluting Kerr-McGee’s Recovery Percentage. Under this scenario, the Recovery Percentage to be applied to Kerr-McGee’s 502(h) Claim would be 2.8%, resulting in an allowed 502(h) Claim of $293 million and a net damages award to plaintiffs of approximately $14.16 billion.
	The Company believes that Kerr-McGee’s 502(h) Claim should be computed by reference to the Bankruptcy Court’s own findings in the Opinion and the language of the Plan, as opposed to being computed by reference to the plaintiffs’ post-petition estimate of the amount of legacy environmental and tort liabilities as of 2010. Accordingly, the Company believes that Kerr-McGee’s 502(h) Claim should be computed by reference to $850 million, which represents the Bankruptcy Court’s finding as to the amount of the net creditor shortfall at the IPO date, which considers the fair value of all of Tronox’s assets and liabilities including the legacy environmental and tort liabilities.
	17. Contingencies (Continued)
	Using the Bankruptcy Court’s framework for calculating the amount of Kerr-McGee’s 502(h) Claim that may be allowed, but applying the Bankruptcy Court’s finding of the $850 million net creditor shortfall instead of the plaintiffs’ post-petition estimate of legacy environmental and tort liabilities used in the Bankruptcy Court’s calculation, results in a 502(h) Claim of $13.609 billion. Furthermore, it is Kerr-McGee’s position that the applicable Recovery Percentage should be determined by the Plan, which states that Kerr-McGee is entitled to the same Class 3 Recovery actually received in the bankruptcy, which exceeded 100%. In accordance with the principles of law and equity outlined in the Opinion, the Company believes that Kerr-McGee is entitled to a Recovery Percentage of 100%, resulting in a net damage award to plaintiffs of $850 million. While it is possible that damages could be determined using a Recovery Percentage of less than 89%, the Company does not believe that this outcome is probable, and therefore a lower Recovery Percentage is not included in the Company’s estimated range of probable loss.
	The following summarizes the Company’s estimated range of probable loss:
	billions, except percentages	Low End of			High End of
		Range of			Range of
		Probable Loss			Probable Loss
	Value of Transferred Assets as of IPO date (1)	$	14.459		$	14.459
	Net Creditor Shortfall/Legacy Liabilities	(0.850		)	(4.000		)
	Allowable 502(h) Claim	$	13.609		$	10.459
	Recovery Percentage	100		%	89		%
	Offset Amount	$	13.609		$	9.309
	Value of Transferred Assets as of IPO date (1)	$	14.459		$	14.459
	Offset Amount	(13.609		)	(9.309		)
	Net Damages	$	0.85		$	5.15
	__________________________________________________________________
	-1	As determined by the Bankruptcy Court.
	The Company’s estimate of the range of probable loss requires significant assumptions. As summarized above, the Company’s estimated range of probable loss uses the net creditor shortfall of $850 million on the low end and plaintiffs’ estimated legacy environmental and tort liabilities of $4.0 billion on the high end. Alternatively, the Bankruptcy Court could use $1.757 billion, which represents the Bankruptcy Court’s findings of fact related to the net present value of the environmental and tort liabilities at the IPO date. Further, the Company’s estimated range of probable loss uses a Recovery Percentage of 100% for the low end and 89% for the high end. Combinations of the above factors would result in damage estimates that are within the Company’s estimated range of probable loss.
	If no 502(h) Claim is allowed, the Company could incur a liability for damages of $14.459 billion, which is materially higher than the Company’s estimated range of probable loss.
	Pre-Judgment Interest and Appreciation  The Bankruptcy Court did not address pre-judgment interest or appreciation in its Opinion. The Bankruptcy Court has discretion in deciding whether to award pre-judgment interest and how such interest may be calculated. The interest rate that may be charged, the date from which such interest is calculated, and whether any such interest is compounded or computed as simple interest may vary. If the Bankruptcy Court chooses to award pre-judgment interest, the amount could be material depending on the amount of net damages awarded in a judgment and the interest rates, dates, and compounding method applied for purposes of calculating the amount of pre-judgment interest.
	17. Contingencies (Continued)
	As noted above, the plaintiffs argued that, in addition to the value of the transferred assets as of 2005, the plaintiffs should recover appreciation in the value of those assets from November 2005 until June 2012. In connection with their appreciation argument, the plaintiffs also are seeking pre-judgment interest applied at a rate of 6% compounded annually from June 2012 until the date of judgment. Appreciation was not addressed by the Bankruptcy Court in its Opinion and it is unclear how any such argument by the plaintiffs will be addressed by the Bankruptcy Court, if at all.
	The inherent uncertainty and lack of information, including the lack of a court-provided framework for whether or how the Bankruptcy Court would consider pre-judgment interest or appreciation, prevent the Company from formulating a reasonable estimate of the amount of pre-judgment interest or appreciation that could be included as part of a judgment. Accordingly, the Company is unable to estimate a range of probable or reasonably possible loss from pre-judgment interest or appreciation at this time, and the Company’s liability accrual does not include any such amounts. The Company will continue to evaluate the extent to which a reasonable estimate of such amounts can be made as additional information regarding the above factors becomes available. Developments that could assist the Company in estimating interest or appreciation include a judgment by the Bankruptcy Court or matters raised in potential hearings regarding the remaining issues being briefed.
	Post-Judgment Interest  Post-judgment interest is mandated by federal law. Post-judgment interest would not begin to accrue until the date a judgment is entered, and would continue until that judgment is paid in full. Because no judgment had been issued as of December 31, 2013, a liability for post-judgment interest has not been incurred. Accordingly, no amount for post-judgment interest has been included in the Company’s accrual or estimated range of probable loss. Further, the Company cannot estimate a range of future liability related to post-judgment interest at this time. At December 31, 2013, the annual interest rate for post-judgment interest was 0.13%.
	Attorneys’ Fees and Costs  In its Opinion, the Bankruptcy Court stated that the plaintiffs could request reimbursement of attorneys’ fees and costs. Based on the Company’s review of relevant law, aside from certain de minimis costs the Company believes there is no basis in law or contract that would permit the plaintiffs to recover attorneys’ fees and costs. Accordingly, the Company has not included any amount related to attorneys’ fees and costs in its estimated range of probable loss. However, it is reasonably possible that a loss related to attorneys’ fees and costs could be as high as the $61 million requested by the plaintiffs.
	Tax Deductibility The Company has concluded that it is more likely than not that 88% of the $850 million loss recognized in 2013 will be deductible for U.S. tax purposes. Accordingly, the Company recognized a deferred tax benefit of $274 million in its 2013 financial statements. If additional losses are accrued in the future, the Company will evaluate the tax deductibility of any such accrual based on the facts and circumstances related to that accrual.
	Liability Outlook  A separate action pending before the U.S. Supreme Court to which Anadarko is not a party, Executive Benefits Insurance Agency v. Arkison, raises certain legal issues including, but not limited to, whether a bankruptcy court has authority to enter a judgment or to make a report and recommendation in a fraudulent transfer case. The Company is uncertain, at this time, what impact any ruling in that case would have on the Adversary Proceeding.
	17. Contingencies (Continued)
	As discussed above, the Company’s $850 million accrued contingent liability as of December 31, 2013, has been established based on the application of accounting guidance to currently available information and the Company’s judgment concerning the application of law to that information. A wide range of possible ultimate outcomes currently exists, and the Company may ultimately incur a liability related to the Adversary Proceeding materially in excess of the current accrued liability. The Company’s liability accrual could also change materially in the near term as events unfold and more information becomes available. Further, it is possible that the Company’s ultimate liability could exceed the currently estimated range of probable loss of $850 million to $5.15 billion. A judgment could also include an award of pre-judgment interest and appreciation, which could be material, as well as attorneys’ fees and costs. In addition, the Company does not believe that the current contingent liability of $850 million accrued at December 31, 2013, is representative of the amount it could be required to pay to reach final resolution of the Adversary Proceeding through settlement. Although the Company does not believe final resolution through settlement to be probable at this time, it expects that any such settlement would require payment of an amount substantially greater than the current accrued liability.
	Following a judgment, the Company would be required either to pay the damage award or appeal the judgment. If the Company pursues its rights through the appellate process, the Company may be required to post a bond or provide sufficient security to stay execution of the judgment by the plaintiffs pending the outcome of the appellate process. As the Bankruptcy Court has not yet issued a judgment, the Company is unable to estimate whether the Company would be required to provide a bond or other security or the potential form or amount of any such bond or other security. However, depending on the amount of the judgment and other factors relating to the appellate process, satisfying any security requirements could have a potentially material negative impact on the Company’s consolidated financial position in the short term.
	Deepwater Horizon Events  In April 2010, the Macondo well in the Gulf of Mexico blew out and an explosion occurred on the Deepwater Horizon drilling rig, resulting in an oil spill. The well was operated by BP Exploration and Production Inc. (BP) and Anadarko held a 25% nonoperated interest. In October 2011, the Company and BP entered into a settlement agreement, mutual releases, and agreement to indemnify relating to the Deepwater Horizon events (Settlement Agreement), under which the Company paid $4.0 billion in cash and transferred its interest in the Macondo well and the Mississippi Canyon Block 252 (Lease) to BP. Pursuant to the Settlement Agreement, the Company is fully indemnified by BP against all claims, causes of action, losses, costs, expenses, liabilities, damages, or judgments of any kind arising out of the Deepwater Horizon events, related damage claims arising under the Oil Pollution Act of 1990 (OPA), claims for natural resource damages (NRD) and assessment costs, and any claims arising under the Operating Agreement with BP (OA). This indemnification is guaranteed by BP Corporation North America Inc. (BPCNA) and, in the event that the net worth of BPCNA declines below an agreed-upon amount, BP p.l.c. has agreed to become the sole guarantor. Under the Settlement Agreement, BP does not indemnify the Company against fines and penalties, punitive damages, shareholder derivative or securities laws claims, or certain other claims.
	Liability Accrual  Below is a discussion of the Company’s current analysis, under applicable accounting guidance, of its potential liability for (i) amounts invoiced by BP under the OA (OA Liabilities), (ii) OPA-related environmental costs, and (iii) other contingent liabilities. Applicable accounting guidance requires the Company to accrue a liability if both (a) it is probable that a liability has been incurred and (b) the amount of that liability can be reasonably estimated.
	The Company is fully indemnified by BP against OPA damage claims, NRD claims and assessment costs, and other potential liabilities. The Company may be required to recognize a liability for these amounts in advance of or in connection with recognizing a receivable from BP for the related indemnity payment. In all circumstances, however, the Company expects that any additional indemnified liability that may be recognized by the Company will be subsequently recovered from BP itself or through the guarantees of BPCNA or BP p.l.c. The Company has not recorded a liability for any costs that are subject to indemnification by BP.
	17. Contingencies (Continued)
	OA Liabilities  Pursuant to the Settlement Agreement, all amounts deemed by BP to have been due under the OA, as well as all future amounts that otherwise would be invoiced to Anadarko under the OA, have been satisfied.
	OPA-Related Environmental Costs  BP, Anadarko, and other parties, including parties that do not own an interest in the Lease, such as the drilling contractor, have received correspondence from the U.S. Coast Guard (USCG) referencing their identification as a “responsible party or guarantor” (RP) under OPA. Under OPA, RPs, including Anadarko, may be jointly and severally liable for costs of well control, spill response, and containment and removal of hydrocarbons, as well as other costs and damage claims related to the spill and spill cleanup. The USCG’s identification of Anadarko as an RP arises as a result of Anadarko’s status as a co-lessee in the Lease.
	Under accounting guidance applicable to environmental liabilities, a liability is presumed probable if the entity is both identified as an RP and associated with the environmental event. The Company’s co-lessee status in the Lease at the time of the event and the subsequent identification and treatment of the Company as an RP satisfies these standards and therefore establishes the presumption that the Company’s potential environmental liabilities related to the Deepwater Horizon events are probable.
	As BP funds OPA-related environmental costs, any potential joint and several liability for these costs is satisfied for all RPs, including Anadarko. This bears significance in that once these costs are funded by BP, such costs are no longer analyzed as OPA-related environmental costs, but instead are analyzed as OA Liabilities. As discussed above, Anadarko has settled its OA Liabilities with BP. Thus, potential liability to the Company for OPA-related environmental costs can arise only where BP does not, or otherwise is unable to, fund all of the OPA-related environmental costs. Under this scenario, the joint and several nature of the liability for these costs could cause the Company to recognize a liability for OPA-related environmental costs. However, the Company is fully indemnified by BP against these costs (including guarantees by BPCNA or BP p.l.c.).
	Gross OPA-Related Environmental Cost Estimate  In prior periods through the fourth quarter of 2011, the Company provided an estimated range of gross OPA-related environmental costs for all identified RPs. This estimate was comprised of spill-response costs and OPA damage claims and was derived from cost information received by the Company from BP. The Company no longer receives Deepwater Horizon-related cost and claims data from BP. Accordingly, the OPA-related environmental cost estimate included in BP’s public releases is the best data available to the Company.
	Based on information included in BP p.l.c.’s public release on February 4, 2014, gross OPA-related environmental costs are estimated to be $10.9 billion, excluding (i) amounts BP has already funded, which constitute settled OA Liabilities; (ii) amounts that in BP’s view cannot reasonably be estimated, which include NRD claims and other litigation damages; (iii) non-OPA-related fines and penalties that may be assessed against Anadarko, including assessments under the Clean Water Act (CWA); and (iv) estimated state and local governmental claims, which BP no longer publicly discloses and, as a result, Anadarko cannot estimate. Actual gross OPA-related environmental costs may vary from those estimated by BP p.l.c. in its public releases, perhaps materially from the above estimate.
	17. Contingencies (Continued)
	Allocable Share of Gross OPA-Related Environmental Costs  Under applicable accounting guidance, the Company is required to estimate its allocable share of gross OPA-related environmental costs. To date, BP has paid all Deepwater Horizon event-related costs, which satisfies the Company’s potential liability for these costs. Additionally, BP has repeatedly stated publicly and in congressional testimony that it will continue to pay these costs. BP’s funding and public commentary has continued subsequent to the release of BP’s own investigation report, the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling’s final report, and the Deepwater Horizon Joint Investigation Team final report, which the Company considers to be significant positive indications in assessing the likelihood of BP continuing to fund all of these costs. Based on BP’s stated intent to continue funding these costs, the Company’s assessment of BP’s financial ability to continue funding these costs, and the impact of BP’s settlements with both of its OA partners, the Company believes the likelihood of BP not continuing to satisfy these claims to be remote. Accordingly, the Company considers zero to be its allocable share of gross OPA-related environmental costs and, consistent with applicable accounting guidance, has not recorded a liability for these amounts.
	Penalties and Fines  These costs include amounts that may be assessed as a result of potential civil and/or criminal penalties under various federal, state, and/or local statutes and/or regulations as a result of the Deepwater Horizon events, including, for example, the CWA, the Outer Continental Shelf Lands Act, the Migratory Bird Treaty Act, and possibly other federal, state, and local laws. The foregoing does not represent an exhaustive list of statutes and regulations that potentially could trigger a penalty or fine assessment against the Company. To date, no penalties or fines have been assessed against the Company. However, in December 2010, the U.S. Department of Justice (DOJ), on behalf of the United States, filed a civil lawsuit in the U.S. District Court in New Orleans, Louisiana (Louisiana District Court) against several parties, including the Company, seeking an assessment of civil penalties under the CWA in an amount to be determined by the Louisiana District Court. In February 2012, the Louisiana District Court entered a declaratory judgment that, as a partial owner of the Macondo well, Anadarko is liable for civil penalties under Section 311 of the CWA. The declaratory judgment addresses liability only, and does not address the amount of any civil penalty. The assessment of a civil penalty against Anadarko has been reserved until a later proceeding to be scheduled by the Louisiana District Court. In August 2012, Anadarko filed a notice of appeal in the U.S. Court of Appeals for the Fifth Circuit concerning that portion of the February 2012 declaratory judgment finding Anadarko liable for civil penalties under the CWA. The appeal is pending and oral arguments were heard in December 2013. The Louisiana District Court has not yet issued a ruling.
	As discussed below, numerous Deepwater Horizon event-related civil lawsuits have been filed against BP and other parties, including the Company. Certain state and local governments have appealed, or have provided indication of a likely appeal of, the Louisiana District Court’s decision that only federal law, and not state law, applies to Deepwater Horizon event-related claims. For example, eleven Louisiana Parish District Attorneys appealed that decision to the U.S. Court of Appeals for the Fifth Circuit. In February 2014, the Fifth Circuit denied the appeal. If any such appeal is successful, state and/or local laws and regulations could become sources of penalties or fines against the Company.
17. Contingencies (Continued)
The Louisiana District Court’s declaratory judgment in February 2012 satisfies the requirement that a loss, arising from the future assessment of a civil penalty against Anadarko, is probable. Notwithstanding the declaratory judgment, the Company currently cannot estimate the amount of any potential civil penalty. The CWA sets forth subjective criteria, including degree of fault and history of prior violations, which significantly influence the magnitude of CWA penalty assessments. As a result of the subjective nature of CWA penalty assessments, the Company currently cannot estimate the amount of any such penalty nor determine a range of potential loss. Furthermore, neither the February 2012 settlement of Deepwater Horizon-related civil penalties (including those under the CWA) by the other nonoperating partner with the United States and five affected Gulf states (Texas, Louisiana, Mississippi, Alabama, and Florida) nor the January 2013 settlement of CWA civil and criminal penalties by the drilling contractor with the United States affects the Company’s current conclusion regarding its ability to estimate potential fines and penalties. The Company lacks insight into those settlements, retains legal counsel separate from the other parties, and was not involved in any manner with respect to those settlements. Events or factors that could assist the Company in estimating the amount of any potential civil penalty or a range of potential loss related to such penalties include (i) an assessment by the DOJ, (ii) a ruling by a court of competent jurisdiction, or (iii) the initiation of substantive settlement negotiations between the Company and the DOJ.
Given the Company’s lack of direct operational involvement in the event, as was reconfirmed by the Louisiana District Court in September 2013 by excluding any evidence of Anadarko’s alleged culpability or fault in the Phase II trial, and the subjective criteria of the CWA, the Company believes that its exposure to CWA penalties will not materially impact the Company’s consolidated financial position, results of operations, or cash flows.
Natural Resource Damages  This category includes future damage claims that may be made by federal and/or state natural resource trustee agencies at the completion of injury assessments and restoration planning. Natural resources generally include land, fish, water, air, wildlife, and other such resources belonging to, managed by, held in trust by, or otherwise controlled by, the federal, state, or local government.
The NRD-assessment process is led by government agencies that act as trustees of natural resources on behalf of the public. Government agencies involved in the process include the Department of Commerce, the Department of the Interior (DOI), and the Department of Defense. These governmental departments, along with the five affected states – Alabama, Florida, Louisiana, Mississippi, and Texas – are referred to as the “Co-Trustees.” The Co-Trustees continue to conduct injury assessment and restoration planning.
The DOJ civil lawsuit filed against BP, the Company, and others seeks unspecified damages for injury to federal natural resources. Not all of the Co-Trustees were a party to this lawsuit; however, during the second quarter of 2011, the states of Alabama and Louisiana each filed NRD-related state law claims against the Company in the Louisiana District Court. In November 2011, the Louisiana District Court dismissed all the NRD-related state law claims asserted against the Company by the states of Alabama and Louisiana. In April 2013, the states of Texas and Mississippi filed NRD-related state law claims against the Company, which were consolidated in the federal Multidistrict Litigation (MDL) action before the Louisiana District Court discussed below and are stayed until further order of the Louisiana District Court.
NRD claims are generally sought after the damage assessment and restoration planning is completed, which may take several years. Thus, the Company remains unable to reasonably estimate the magnitude of any NRD claim. The Company anticipates that BP will satisfy any NRD claim, which eliminates any potential liability to Anadarko for such costs. In the event any NRD damage claim is made directly against Anadarko, the Company is fully indemnified by BP against such claims (including guarantees by BPCNA or BP p.l.c.).
17. Contingencies (Continued)
Civil Litigation Damage Claims  Numerous Deepwater Horizon event-related civil lawsuits have been filed against BP and other parties, including the Company by, among others, fishing, boating, and shrimping enterprises and industry groups; restaurants; commercial and residential property owners; certain rig workers or their families; the States of Alabama, Louisiana, Texas, and Mississippi, and several of their political subdivisions; the DOJ; environmental non-governmental organizations; and certain Mexican states. Many of the lawsuits filed assert various claims of negligence, gross negligence, and violations of several federal and state laws and regulations, including, among others, OPA; the Comprehensive Environmental Response, Compensation, and Liability Act; the Clean Air Act; the CWA; and the Endangered Species Act; or challenge existing permits for operations in the Gulf of Mexico. Generally, the plaintiffs are seeking actual damages, punitive damages, declaratory judgment, and/or injunctive relief.
This litigation has been consolidated into a federal MDL action pending before Judge Carl Barbier in the Louisiana District Court. In March 2012, BP and the Plaintiffs’ Steering Committee entered into a tentative settlement agreement to resolve the substantial majority of economic loss and medical claims stemming from the Deepwater Horizon events, which the Louisiana District Court approved in orders issued in December 2012 and January 2013. Only OPA claims seeking economic loss damages against the Company remain. In addition, certain state and local governments have appealed, or have provided indication of a likely appeal of, the Louisiana District Court’s decision that only federal law, and not state law, applies to Deepwater Horizon event-related claims. Certain Mexican states also have appealed the dismissal of their claims against BP, the Company, and others. The Company, pursuant to the Settlement Agreement, is fully indemnified by BP against losses arising as a result of claims for damages, irrespective of whether such claims are based on federal (including OPA) or state law.
The first phase of the trial in the MDL commenced in February 2013 (Phase I). In April 2013, all parties rested their Phase I cases. Findings of fact, post-trial briefs, and responsive briefs were submitted in July 2013. BP, BP p.l.c., the United States, state and local governments, Halliburton Energy Services, Inc. (Halliburton), and Transocean Ltd. (Transocean) participated in Phase I. Anadarko was excused from participation in Phase I. The issues tried in Phase I included the cause of the blow-out and all related events leading up to April 22, 2010, the date the Deepwater Horizon sank, as well as allocation of fault. The allocation of fault remains in the Phase I trial because Halliburton and Transocean have not settled with any of the parties and each wishes to prove to the Louisiana District Court that their respective company was not at fault. The second phase of trial began in September 2013 (Phase II) and in November 2013 the parties rested their Phase II cases. The issues tried in Phase II included spill-source control and quantification of the spill for the period from April 20, 2010, until the well was capped. The Company, BP, BP p.l.c., the United States, state and local governments, Halliburton, and Transocean participated in Phase II of the trial. Prior to commencement of Phase II, the judge entered an order excluding any evidence of Anadarko’s alleged culpability or fault during Phase II.
Two separate class action complaints were filed in June and August 2010, in the U.S. District Court for the Southern District of New York (New York District Court) on behalf of purported purchasers of the Company’s stock between June 9, 2009, and June 12, 2010, against Anadarko and certain of its officers. The complaints allege causes of action arising pursuant to the Securities Exchange Act of 1934 for purported misstatements and omissions regarding, among other things, the Company’s liability related to the Deepwater Horizon events. The plaintiffs seek an unspecified amount of compensatory damages, including interest thereon, as well as litigation fees and costs. In November 2010, the New York District Court consolidated the two cases. In March 2012, the New York District Court granted the plaintiffs’ motion to transfer venue to the U.S. District Court for the Southern District of Texas - Houston Division (Texas District Court). In May 2012, the Texas District Court granted the defendants’ motion to transfer the consolidated action within the district to Judge Keith P. Ellison. In July 2012, the plaintiffs filed their First Amended Consolidated Class Action Complaint. The defendants filed a renewed motion to dismiss in the Texas District Court in September 2012. In July 2013, the Texas District Court dismissed the claims relating to all but one of the alleged misstatements asserted in the plaintiffs’ complaint. The Texas District Court gave the plaintiffs 30 days to amend the complaint to attempt to rehabilitate the claims that were dismissed. The plaintiffs declined to amend the complaint. The Company filed its answer to the complaint in September 2013. The parties have not commenced discovery.
17. Contingencies (Continued)
In September 2010, a purported shareholder made a demand on the Company’s Board of Directors (the Board) to investigate allegations of breaches of duty by members of management related to the Deepwater Horizon events. The Board received a supplemental demand letter from the shareholder in March 2012. The Board considered each of the demand letters in January 2011 and April 2012 and determined that it would not be in the best interest of the Company to pursue the issues alleged in the demand letters. In May 2013, a shareholder derivative petition was filed in the 215th District Court of Harris County, Texas by the shareholder against Anadarko (as a nominal defendant) and certain current and former directors and officers. The petition alleges breach of fiduciary duties, unjust enrichment, abuse of control, and gross mismanagement in connection with the Deepwater Horizon events. The plaintiff seeks an unspecified amount of damages, certain changes to the Company’s governance and internal procedures, disgorgement of profits, and reimbursement of litigation fees and costs. By agreement of the parties, this case has been stayed.
Given the various stages of these matters, the Company currently cannot assess the probability of losses, or reasonably estimate a range of any potential losses, related to ongoing proceedings. The Company intends to vigorously defend itself, its officers, and its directors in each of these matters, and will avail itself of the indemnities provided by BP against civil damages.
Remaining Liability Outlook  It is possible that the Company may recognize additional Deepwater Horizon event-related liabilities for potential fines and penalties, shareholder claims, and certain other claims not covered by the indemnification provisions of the Settlement Agreement; however, the Company does not believe that any potential liability attributable to the foregoing items, individually or in the aggregate, will have a material impact on the Company’s consolidated financial position, results of operations, or cash flows. This assessment takes into account certain qualitative factors, including the subjective and fault-based nature of CWA penalties, the Company’s indemnification by BP against certain damage claims as discussed above, BP’s creditworthiness, the merits of the shareholder claims, and directors’ and officers’ insurance coverage related to outstanding shareholder claims.
The Company will continue to monitor the MDL and other legal proceedings discussed above as well as federal investigations related to the Deepwater Horizon events. The Company cannot predict the nature of evidence that may be discovered during the course of legal proceedings or the timing of completion of any legal proceedings.
Although the Company is fully indemnified by BP against OPA damage claims, NRD claims and assessment costs, and certain other potential liabilities, the Company may be required to recognize a liability for these amounts in advance of or in connection with recognizing a receivable from BP for the related indemnity payment. In all circumstances, however, the Company expects that any additional indemnified liability that may be recognized by the Company will be subsequently recovered from BP itself or through the guarantees of BPCNA or BP p.l.c.
17. Contingencies (Continued)
Other Litigation  In December 2008, Anadarko sold its interest in the Peregrino heavy-oil field offshore Brazil. The Company is currently litigating a dispute with the Brazilian tax authorities regarding the tax rate applicable to the transaction. Currently, $144 million, the amount of tax originally in dispute, resides in a judicially controlled Brazilian bank account pending final resolution of the matter and is included in other assets on the Company’s Consolidated Balance Sheet at December 31, 2013.
In July 2009, the lower judicial court ruled in favor of the Brazilian tax authorities. The Company appealed this decision to the Brazilian Regional courts, which upheld the lower court’s ruling in favor of the Brazilian tax authorities in December 2011. In April 2012, the Company filed simultaneous appeals to the Brazilian Superior Court and the Brazilian Supreme Court. The Brazilian Superior Court and the Brazilian Supreme Court have agreed to hear the case and the Company currently is awaiting the setting of initial hearing dates. In August 2013, following a determination by an administrative court in a related matter that the amount of tax in dispute was not calculated properly, the Company filed a petition requesting the withdrawal of a portion of the judicial deposit to the extent it exceeds $47 million, the amount of tax currently in dispute, and any interest on such amount.
The Company believes that it will more likely than not prevail in Brazilian courts. Therefore, no tax liability has been recorded for Peregrino divestiture-related litigation at December 31, 2013. The Company continues to vigorously defend itself in Brazilian courts.
Algeria Exceptional Profits Tax Settlement  In 2006, the Algerian parliament approved legislation establishing an exceptional profits tax on foreign companies’ Algerian oil production and issued regulations implementing this legislation. The Company disagreed with Sonatrach’s collection of the exceptional profits tax and initiated arbitration against Sonatrach in 2009. In March 2012, the Company and Sonatrach resolved this dispute and the resolution provided for the transfer of $1.7 billion of crude oil to the Company over a 12-month period ending in mid-2013.
Guarantees and Indemnifications  The Company provides certain indemnifications in relation to asset dispositions. These indemnifications typically relate to disputes, litigation, or tax matters existing at the date of disposition. In 2013, as a result of a bankruptcy declaration by a third party, the DOI ordered Anadarko to decommission offshore wells and production facilities previously sold to the third party and not related to the Company’s current operations. During 2013, the Company recognized a decommissioning charge of $117 million, reported in other (income) expense, net in the Consolidated Statement of Income. Anadarko expects to complete decommissioning of the production facilities in 2014 and the wells in 2015. Decommissioning obligations of $21 million were included in accrued expenses and $85 million were included in other long-term liabilities on the Consolidated Balance Sheet at December 31, 2013. Actual costs may vary from this estimate; however, the Company does not believe that any such change will materially impact its consolidated financial position, results of operations, or cash flows.
17. Contingencies (Continued)
Environmental Matters  Anadarko is also subject to various environmental-remediation and reclamation obligations arising from federal, state, and local laws and regulations. The Company’s Consolidated Balance Sheets include liabilities of $126 million at December 31, 2013, and $81 million at December 31, 2012, for remediation and reclamation obligations. The current portion of these amounts was included in accounts payable and the long-term portion of these amounts was included in other long-term liabilities—other on the Company’s Consolidated Balance Sheets. The Company continually monitors remediation and reclamation processes and adjusts its liability for these obligations as necessary.
The Company was previously notified by the California Department of Toxic Substances Control (DTSC) that, as a result of a prior acquisition, it is one of 27 potentially responsible parties with respect to a landfill located in West Covina, California. While no agreement is in place with the DTSC, the Company has recorded a $50 million restoration liability with respect to the site, representing the current estimated obligation, which is included in the Company’s liability balance at December 31, 2013. The Company could incur additional obligations if any of the potentially responsible parties are ultimately not able to fund their allocated share of the costs or if the DTSC requires a more costly remedial approach. It is possible that the Company’s current estimate of probable loss related to this matter could change, perhaps materially, in the future.

Other_Taxes

Other Taxes	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Other Taxes	'
	18. Other Taxes
	Taxes incurred, other than income taxes, for the years ended December 31 were as follows:
	millions	2013		2012		2011
	Production and severance	$	706	$	855	$	1,094
	Ad valorem	277		238		265
	Other	94		131		133
	Total	$	1,077	$	1,224	$	1,492

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Income Taxes	'
	19. Income Taxes
	The following summarizes components of income tax expense (benefit) for the years ended December 31:
	millions	2013				2012				2011
	Current
	Federal	$	113			$	45			$	(381	)
	State	42				25				1
	Foreign	873				891				977
		1,028				961				597
	Deferred
	Federal	94				(30		)		(1,470		)
	State	(9		)		115				(68		)
	Foreign	52				74				85
		137				159				(1,453		)
	Income tax expense (benefit)	$	1,165			$	1,120			$	(856	)
	Total income taxes differed from the amounts computed by applying the U.S. federal statutory income tax rate to income (loss) before income taxes. The following summarizes the sources of these differences for the years ended December 31:
	millions except percentages	2013				2012				2011
	Income (loss) before income taxes
	Domestic	$	428			$	132			$	(5,416	)
	Foreign	1,678				3,433				1,992
	Total	$	2,106			$	3,565			$	(3,424	)
	U.S. federal statutory tax rate	35		%		35		%		35		%
	Tax computed at the U.S. federal statutory rate	$	737			$	1,248			$	(1,198	)
	Adjustments resulting from
	State income taxes (net of federal income tax benefit)	23				93				(44		)
	Tax impact from foreign operations	167				226				93
	Non-deductible Algerian exceptional profits tax	144				188				258
	Non-taxable Algeria exceptional profits tax settlement	13				(679		)		—
	Deferred tax adjustments	76				22				5
	Non-deductible Tronox-related contingent loss	36				—				—
	Income attributable to noncontrolling interests	(48		)		(24		)		(28		)
	Items resulting from business acquisitions	—				—				19
	Other—net	17				46				39
	Income tax expense (benefit)	$	1,165			$	1,120			$	(856	)
	Effective tax rate	55		%		31		%		25		%
	19. Income Taxes (Continued)
	The following summarizes components of total deferred taxes at December 31:
	millions	2013				2012
	Federal	$	(8,246	)		$	(7,890	)
	State, net of federal	(332		)		(325		)
	Foreign	(307		)		(216		)
	Total deferred taxes	$	(8,885	)		$	(8,431	)
	The following summarizes tax effects of temporary differences that give rise to significant portions of the deferred tax assets (liabilities) at December 31:
	millions	2013				2012
	Current deferred tax assets	$	412			$	328
	Valuation allowances on deferred tax assets not expected to be realized	(52		)		—
	Net current deferred tax assets	360				328
	Oil and gas exploration and development operations	(8,213		)		(8,683		)
	Mineral operations	(410		)		(408		)
	Midstream and other depreciable properties	(1,586		)		(1,295		)
	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	)
	Changes to valuation allowances, due to changes in judgment regarding the future realizability of deferred tax assets, were an increase of $2 million in 2013, an increase of $23 million in 2012, and a decrease of $17 million in 2011. The following summarizes changes in the balance of valuation allowances on deferred tax assets:
	millions	2013				2012				2011
	Balance at January 1	$	(922	)		$	(555	)		$	(454	)
Additions	(38		)		(426		)		(138		)
Reductions	142				59				37
Balance at December 31	$	(818	)		$	(922	)		$	(555	)
19. Income Taxes (Continued)
The following summarizes taxes receivable (payable) related to income tax expense (benefit) at December 31:
Balance Sheet Classification		2013				2012
Income taxes receivable
Accounts receivable—other		$	66			$	179
Other assets		35				2
		101				181
Income taxes (payable)
Accrued expense		(82		)		(38		)
Net income taxes receivable (payable)		$	19			$	143
Tax carryforwards available for use on future income tax returns at December 31, 2013, were as follows:
millions	Domestic				Foreign				Expiration
Net operating loss—foreign	$	—			$	1,265			2014 - Indefinite
Net operating loss—state	$	4,527			$	—			2014-2032
Foreign tax credits	$	325			$	—			2015-2023
Texas margins tax credit	$	35			$	—			2026
Changes in the balance of unrecognized tax benefits excluding interest and penalties on uncertain tax positions were as follows:
	Assets (Liabilities)
millions	2013				2012				2011
Balance at January 1	$	(46	)		$	(31	)		$	(32	)
Increases related to prior-year tax positions	(54		)		(17		)		—
Decreases related to prior-year tax positions	3				3				3
Increases related to current-year tax positions	(72		)		(1		)		(10		)
Settlements	5				—				8
Lapse of statute of limitations	17				—				—
Balance at December 31	$	(147	)		$	(46	)		$	(31	)
Included in the 2013 ending balance of unrecognized tax benefits presented above are potential benefits of $(129) million that would affect the effective tax rate on income if recognized. Based on the Company’s existing activities, a $99 million increase in valuation allowance would be expected to offset a portion of the potential benefit of $(129) million. Also included in the 2013 ending balance are benefits of $(18) million related to tax positions for which the ultimate deductibility is highly certain, but the timing of such deductibility is uncertain. The Company estimates that $(4) million to $(10) million of unrecognized tax benefits related to adjustments to taxable income and credits previously recorded pursuant to the accounting standard for accounting for tax uncertainties will reverse within the next 12 months due to expiration of statutes of limitation and audit settlements.
The Company had accrued approximately $8 million of interest related to uncertain tax positions at December 31, 2013, and $28 million at December 31, 2012. The Company recognized interest and penalties in income tax expense (benefit) of $(20) million during 2013 and $9 million during 2012.
19. Income Taxes (Continued)
Anadarko is subject to audit by tax authorities in the U.S. federal, state, and local tax jurisdictions as well as in various foreign jurisdictions. The Company is currently under routine examination by the U.S. Internal Revenue Service for the tax years 2007 through 2013.
Income tax audits and the Company’s acquisition and divestiture activity have given rise to tax disputes in U.S. and foreign jurisdictions. See Note 17—Contingencies—Other Litigation. Management does not believe that the final resolution of outstanding tax audits and litigation will have a material adverse effect on the Company’s consolidated financial position, results of operations, or cash flows.
The following lists the tax years subject to examination by major tax jurisdiction:
	Tax Year
United States	2007-2013
China	2009-2013
Algeria	2010-2013
Ghana	2006-2013

Supplemental_Cash_Flow_Informa

Supplemental Cash Flow Information	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Supplemental Cash Flow Information	'
	20. Supplemental Cash Flow Information
	The following summarizes cash paid (received) for interest (net of amounts capitalized) and income taxes, as well as non-cash investing and financing transactions for the years ended December 31:
	millions	2013		2012			2011
	Cash paid (received)
	Interest	$	627	$	684		$	806
	Income taxes	169		(300		)	262
	Non-cash investing activities
	Fair value of properties and equipment exchanged in non-cash	$	62	$	65		$	19
	transactions
	Gain related to the fair-value remeasurement of Anadarko’s	—		—			21
	pre-acquisition 7% equity interest in the Wattenberg Plant
	Non-cash investing and financing activities
	Capital lease obligation	$	8	$	—		$	(118	)
	Floating production, storage, and offloading vessel construction	17		—			—
	period obligation

Segment_Information

Segment Information	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Segment Information	'
	21. Segment Information
	Anadarko’s business segments are separately managed due to distinct operational differences and unique technology, distribution, and marketing requirements. The Company’s three reporting segments are oil and gas exploration and production, midstream, and marketing. The oil and gas exploration and production segment explores for and produces natural gas, crude oil, condensate, and NGLs, and plans for the development and operation of the Company’s LNG project in Mozambique. The midstream segment engages in gathering, processing, treating, and transporting Anadarko and third-party oil, natural-gas, and NGLs production. The midstream reporting segment consists of two operating segments, WES and other midstream, which are aggregated into one reporting segment due to similar financial and operating characteristics. The marketing segment sells much of Anadarko’s production, as well as third-party purchased volumes.
	21. Segment Information (Continued)
	To assess the performance of Anadarko’s operating segments, the chief operating decision maker analyzes Adjusted EBITDAX. The Company defines Adjusted EBITDAX as income (loss) before income taxes; exploration expense; depreciation, depletion, and amortization (DD&A); impairments; interest expense; total (gains) losses on derivatives, net, less net cash received in settlement of commodity derivatives; and certain items not related to the Company’s normal operations, less net income attributable to noncontrolling interests. During the periods presented, certain items not related to the Company’s normal operations included Deepwater Horizon settlement and related costs, Algeria exceptional profits tax settlement, Tronox-related contingent loss, and certain other nonoperating items included in other (income) expense, net. The Company’s definition of Adjusted EBITDAX excludes exploration expense, as it is not an indicator of operating efficiency for a given reporting period. However, exploration expense is monitored by management as part of costs incurred in exploration and development activities. Similarly, DD&A and impairments are excluded from Adjusted EBITDAX as a measure of segment operating performance because capital expenditures are evaluated at the time capital costs are incurred. Adjusted EBITDAX also excludes interest expense to allow for assessment of segment operating results without regard to Anadarko’s financing methods or capital structure. Total (gains) losses on derivatives, net, less net cash received in settlement of commodity derivatives, are excluded from Adjusted EBITDAX because these (gains) losses are not considered a measure of asset operating performance. Finally, net income attributable to noncontrolling interests is excluded from the Company’s measure of Adjusted EBITDAX because it represents earnings that are not attributable to the Company’s common stockholders.
	Management believes that the presentation of Adjusted EBITDAX provides information useful in assessing the Company’s financial condition and results of operations and that Adjusted EBITDAX is a widely accepted financial indicator of a company’s ability to incur and service debt, fund capital expenditures, and make distributions to stockholders. Adjusted EBITDAX, as defined by Anadarko, may not be comparable to similarly titled measures used by other companies and should be considered in conjunction with net income (loss) attributable to common stockholders and other performance measures, such as operating income or cash flows from operating activities. Below is a reconciliation of consolidated Adjusted EBITDAX to income (loss) before income taxes for the years ended December 31:
	millions	2013			2012			2011
	Income (loss) before income taxes	$	2,106		$	3,565		$	(3,424	)
	Exploration expense	1,329			1,946			1,076
	DD&A	3,927			3,964			3,830
	Impairments	794			389			1,774
	Interest expense	686			742			839
	Total (gains) losses on derivatives, net, less net cash received in	(307		)	443			675
	settlement of commodity derivatives
	Deepwater Horizon settlement and related costs	15			18			3,930
	Algeria exceptional profits tax settlement	33			(1,797		)	—
	Tronox-related contingent loss	850			(250		)	250
	Certain other nonoperating items	110			—			—
	Less net income attributable to noncontrolling interests	140			54			81
	Consolidated Adjusted EBITDAX	$	9,403		$	8,966		$	8,869
	21. Segment Information (Continued)
	The Company’s accounting policies for individual segments are the same as those described in the summary of significant accounting policies, with the following exception: certain intersegment commodity contracts may meet the U.S. Generally Accepted Accounting Principles (GAAP) definition of a derivative instrument, which would be accounted for at fair value under GAAP. However, Anadarko does not recognize any mark-to-market adjustments on such intersegment arrangements. Additionally, intersegment asset transfers are accounted for at historical cost basis, and do not give rise to gain or loss recognition.
	Information presented below as “Other and Intersegment Eliminations” includes results from hard-minerals royalty arrangements and corporate, financing, and certain derivative activities. The following summarizes selected financial information for Anadarko’s reporting segments:
	millions	Oil and Gas			Midstream			Marketing			Other and			Total
		Exploration									Intersegment
		& Production									Eliminations
	2013
	Sales revenues	$	7,090		$	387		$	7,390		$	—		$	14,867
	Intersegment revenues	6,405			1,105			(6,859		)	(651		)	—
	Gains (losses) on divestitures and other, net	(622		)	(1		)	—			337			(286		)
	Total revenues and other	12,873			1,491			531			(314		)	14,581
	Operating costs and expenses (1)	3,635			843			652			20			5,150
	Net cash received in settlement of	—			—			—			(95		)	(95		)
	commodity derivatives
	Other (income) expense, net (2)	—			—			—			(21		)	(21		)
	Net income attributable to noncontrolling	—			140			—			—			140
	interests
	Total expenses and other	3,635			983			652			(96		)	5,174
	Total (gains) losses on derivatives, net	—			—			(4		)	—			(4		)
	included in marketing revenue, less net
	cash received in settlement
	Adjusted EBITDAX	$	9,238		$	508		$	(125	)	$	(218	)	$	9,403
	Net properties and equipment	$	33,409		$	5,408		$	9		$	2,103		$	40,929
	Capital expenditures	$	7,008		$	1,248		$	—		$	267		$	8,523
	Goodwill	$	5,317		$	175		$	—		$	—		$	5,492
	21. Segment Information (Continued)
	millions	Oil and Gas			Midstream			Marketing			Other and			Total
		Exploration									Intersegment
		& Production									Eliminations
	2012
	Sales revenues	$	6,752		$	325		$	6,230		$	—		$	13,307
	Intersegment revenues	5,318			959			(5,734		)	(543		)	—
	Gains (losses) on divestitures and other, net	(65		)	(8		)	—			177			104
	Total revenues and other	12,005			1,276			496			(366		)	13,411
	Operating costs and expenses (1)	3,505			748			616			295			5,164
	Net cash received in settlement of	—			—			—			(753		)	(753		)
	commodity derivatives
	Other (income) expense, net (2)	—			—			—			(4		)	(4		)
	Net income attributable to noncontrolling	—			54			—			—			54
	interests
	Total expenses and other	3,505			802			616			(462		)	4,461
	Total (gains) losses on derivatives, net	—			—			16			—			16
	included in marketing revenue, less net
	cash received in settlement
Adjusted EBITDAX	$	8,500		$	474		$	(104	)	$	96		$	8,966
Net properties and equipment	$	32,024		$	4,459		$	9		$	1,906		$	38,398
Capital expenditures	$	5,906		$	1,250		$	—		$	155		$	7,311
Goodwill	$	5,317		$	175		$	—		$	—		$	5,492
2011
Sales revenues	$	7,519		$	342		$	6,023		$	(2	)	$	13,882
Intersegment revenues	5,005			957			(5,515		)	(447		)	—
Gains (losses) on divestitures and other, net	(41		)	(13		)	—			139			85
Total revenues and other	12,483			1,286			508			(310		)	13,967
Operating costs and expenses (1)	3,696			786			559			186			5,227
Net cash received in settlement of	—			—			—			(226		)	(226		)
commodity derivatives
Other (income) expense, net (2)	—			—			—			4			4
Net income attributable to noncontrolling	—			81			—			—			81
interests
Total expenses and other	3,696			867			559			(36		)	5,086
Total (gains) losses on derivatives, net	—			—			(12		)	—			(12		)
included in marketing revenue, less net
cash received in settlement
Adjusted EBITDAX	$	8,787		$	419		$	(63	)	$	(274	)	$	8,869
Net properties and equipment	$	32,235		$	3,432		$	9		$	1,825		$	37,501
Capital expenditures	$	5,026		$	1,420		$	—		$	107		$	6,553
Goodwill	$	5,475		$	166		$	—		$	—		$	5,641
__________________________________________________________________
(1)	Operating costs and expenses exclude 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 Tronox-related contingent loss since this expense is excluded from Adjusted EBITDAX.
21. Segment Information (Continued)
The following represents Anadarko’s sales revenues (based on the origin of the sales) and net properties and equipment by geographic area:
	Years Ended December 31,
millions	2013			2012			2011
Sales Revenues
United States	$	11,290		$	9,911		$	10,477
Algeria	2,184			2,182			2,258
Other International	1,393			1,214			1,147
Total	$	14,867		$	13,307		$	13,882
	December 31,
millions	2013			2012
Net Properties and Equipment
United States	$	35,486		$	33,337
Algeria	1,582			1,575
Other International	3,861			3,486
Total	$	40,929		$	38,398
Major Customers  Sales to Total S.A. were $2.0 billion in 2013 and $1.9 billion in 2012. These amounts are included in the oil and gas exploration and production reporting segment. In 2011, there were no sales to individual customers that exceeded 10% of the Company’s total sales revenues.

Pension_Plans_Other_Postretire

Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Pension Plans and Other Postretirement Benefits	'
	22. Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans
	The Company has contributory and non-contributory defined-benefit pension plans, which include both qualified and supplemental plans. The Company also provides certain health care and life insurance benefits for certain retired employees. Retiree health care benefits are funded by contributions from the retiree, and in certain circumstances, contributions from the Company. The Company’s retiree life insurance plan is non-contributory.
	While reported benefit obligations exceed the fair value of pension and other postretirement plan assets at December 31, 2013, the Company monitors the funded status of its funded pension plans to ensure that plan funds are sufficient to continue paying benefits. During 2013, the Company made contributions of $123 million to its funded pension plans, $37 million to its unfunded pension plans, and $14 million to its unfunded other postretirement benefit plans. Contributions to funded plans increase plan assets while contributions to unfunded plans are used to fund current benefit payments. The Company expects to contribute $103 million to its funded pension plans, $19 million to its unfunded pension plans, and $15 million to its unfunded other postretirement benefit plans in 2014.
	22. Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans (Continued)
	The following sets forth changes in the benefit obligations and fair value of plan assets for the Company’s pension and other postretirement benefit plans for the years ended December 31, 2013 and 2012, as well as the funded status of the plans and amounts recognized in the financial statements at December 31, 2013 and 2012:
		Pension Benefits								Other Benefits
	millions	2013				2012				2013			2012
	Change in benefit obligation
	Benefit obligation at beginning of year	$	2,297			$	2,024			$	359		$	354
	Service cost	85				76				9			9
	Interest cost	78				85				14			16
	Actuarial (gain) loss	(156		)		224				(74		)	(1		)
	Participant contributions	—				1				4			3
	Benefit payments	(149		)		(117		)		(18		)	(22		)
	Foreign-currency exchange-rate changes	3				4				—			—
	Benefit obligation at end of year (1)	$	2,158			$	2,297			$	294		$	359
	Change in plan assets
	Fair value of plan assets at beginning of year	$	1,462			$	1,308			$	—		$	—
	Actual return on plan assets	278				159				—			—
	Employer contributions	160				107				14			19
	Participant contributions	—				1				4			3
	Benefit payments	(149		)		(117		)		(18		)	(22		)
	Foreign-currency exchange-rate changes	3				4				—			—
	Fair value of plan assets at end of year	$	1,754			$	1,462			$	—		$	—
	Funded status of the plans at end of year	$	(404	)		$	(835	)		$	(294	)	$	(359	)
	Total recognized amounts in the balance sheet consist of
	Other assets	$	37			$	30			$	—		$	—
	Accrued expenses	(19		)		(44		)		(15		)	(16		)
	Other long-term liabilities—other	(422		)		(821		)		(279		)	(343		)
	Total	$	(404	)		$	(835	)		$	(294	)	$	(359	)
	Total recognized amounts in accumulated other
	comprehensive income consist of
	Prior service cost (credit)	$	(1	)		$	(2	)		$	2		$	3
	Net actuarial (gain) loss	441				916				(78		)	(4		)
	Total	$	440			$	914			$	(76	)	$	(1	)
	__________________________________________________________________
	(1)	The accumulated benefit obligation for all defined-benefit pension plans was $1.8 billion at December 31, 2013, and $2.1 billion at December 31, 2012.
	22. Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans (Continued)
	The following summarizes the Company’s defined-benefit pension plans with accumulated benefit obligations in excess of plan assets for the years ended December 31:
	millions	2013				2012
	Projected benefit obligation	$	2,047			$	2,198
	Accumulated benefit obligation	1,742				2,054
	Fair value of plan assets	1,606				1,333
	The following summarizes the Company’s pension and other postretirement benefit cost and amounts recognized in other comprehensive income (before tax benefit) for the years ended December 31:
		Pension Benefits											Other Benefits
	millions	2013				2012				2011			2013				2012		2011
	Components of net periodic benefit cost
	Service cost	$	85			$	76			$	78		$	9			$	9	$	9
	Interest cost	78				85				85			14				16		16
	Expected return on plan assets	(91		)		(91		)		(85		)	—				—		—
	Amortization of net actuarial loss (gain)	118				93				85			—				—		—
	Amortization of net prior service cost (credit)	—				—				2			1				2		—
	Settlement loss	14				—				—			—				—		—
	Net periodic benefit cost	$	204			$	163			$	165		$	24			$	27	$	25
	Amounts recognized in other comprehensive
	income (expense)
	Net actuarial gain (loss)	$	342			$	(156	)		$	(183	)	$	74			$	1	$	(30	)
	Amortization of net actuarial (gain) loss	118				93				85			—				—		—
	Net prior service (cost) credit	—				—				12			—				—		—
	Amortization of net prior service cost (credit)	—				—				2			1				2		—
	Settlement loss	14				—				—			—				—		—
	Total amounts recognized in other	$	474			$	(63	)		$	(84	)	$	75			$	3	$	(30	)
	comprehensive income (expense)
In 2014, an estimated $26 million of net actuarial loss for the pension and other postretirement plans will be amortized from accumulated other comprehensive income into net periodic benefit cost.
The following summarizes the weighted-average assumptions used by the Company in determining the pension and other postretirement benefit obligations at December 31:
	Pension Benefits						Other Benefits
	2013			2012			2013			2012
Discount rate	4.75	%		3.5	%		5.25	%		4	%
Rates of increase in compensation levels	5	%		4.5	%		5.25	%		4.5	%
22. Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans (Continued)
Accumulated and projected benefit obligations are measured as the present value of future cash payments. The Company discounts those cash payments using a discount rate that reflects the weighted average of market-observed yields for select high-quality (AA-rated) fixed-income securities with cash flows that correspond to the expected amounts and timing of benefit payments. The discount-rate assumption used by the Company represents an estimate of the interest rate at which the pension and other postretirement benefit obligations could effectively be settled on the measurement date. Assumed rates of compensation increases for active participants vary by age group, with the resulting weighted-average assumed rate (weighted by the plan-level benefit obligation) provided in the preceding table.
The following summarizes the weighted-average assumptions used by the Company in determining the net periodic pension and other postretirement benefit cost:
	Pension Benefits									Other Benefits
	2013			2012			2011			2013		2012			2011
Discount rate	3.5	%		4.5	%		4.75	%		4	%	4.75	%		5.25	%
Long-term rate of return on plan assets	7	%		7	%		7	%		N/A		N/A			N/A
Rates of increase in compensation levels	4.5	%		4.5	%		5	%		4.5	%	4.5	%		5	%
At December 31, 2013, an 8.00% annual rate of increase in the per-capita cost of covered health care benefits for 2014 was assumed for purposes of measuring other postretirement benefit obligations. At December 31, 2012, an 8.00% annual rate of increase in the per-capita cost of covered health care benefits for 2013 was assumed for purposes of measuring other postretirement benefit obligations. This rate is expected to gradually decrease to 5.00% in 2019 and beyond. The assumed health care cost trend rate can have a significant effect on the cost and obligation amounts reported for the health care plan. A 1% change in the assumed health care cost trend rate over the projected period would have the following effects:
millions	1% Increase				1% Decrease
Effect on total of service and interest cost components	$	3			$	(2	)
Effect on other postretirement benefit obligation	$	23			$	(20	)
22. Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans (Continued)
Plan Assets
Investment Policies and Strategies  The Company has adopted a balanced, diversified investment strategy, with the intent of maximizing returns without exposure to undue risk. Investments are typically made through investment managers across several investment categories (domestic equity securities, international equity securities, fixed-income securities, real estate, hedge funds, and private equity), with selective exposure to Growth/Value investment styles. Performance for each investment is measured relative to the appropriate index benchmark for its category. Target asset-allocation percentages by major category are 45%-55% equity securities, 20%-30% fixed income, and up to 25% in a combination of other investments such as real estate, hedge funds, and private equity. Investment managers have full discretion as to investment decisions regarding funds under their management to the extent permitted within investment guidelines.
Although investment managers may, at their discretion and within investment guidelines, invest in Anadarko securities, there are no direct investments in Anadarko securities included in plan assets. There may be, however, indirect investments in Anadarko securities through the plans’ collective fund investments. The expected long-term rate of return on plan assets assumption was determined using the year-end 2013 pension investment balances by asset class and expected long-term asset allocation. The expected return for each asset class reflects capital-market projections formulated using a forward-looking building-block approach, while also taking into account historical return trends and current market conditions. Equity returns generally reflect long-term expectations of real earnings growth, dividend yield, and inflation. Returns on fixed-income securities are generally developed based on expected inflation, real bond yield, and risk spread (as appropriate), adjusted for the expected effect that changing yields have on the rate of return. Other asset-class returns are derived from their relationship to the equity and fixed-income markets.
22. Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans (Continued)
The fair value of the Company’s pension plan assets by asset class and input level within the fair-value hierarchy were as follows:
millions
December 31, 2013	Level 1				Level 2				Level 3			Total
Investments
Cash and cash equivalents	$	17			$	80			$	—		$	97
Fixed income
Mortgage-backed securities	—				54				—			54
U.S. government securities	—				52				—			52
Other fixed-income securities (1)	42				197				—			239
Equity securities
Domestic	445				116				—			561
International	148				303				—			451
Other
Real estate	—				47				86			133
Private equity	—				—				72			72
Hedge funds and other alternative strategies	31				—				79			110
Total investments (2)	$	683			$	849			$	237		$	1,769
Liabilities
Hedge funds and other alternative strategies	$	(17	)		$	—			$	—		$	(17	)
Total liabilities	$	(17	)		$	—			$	—		$	(17	)
December 31, 2012
Investments
Cash and cash equivalents	$	23			$	36			$	—		$	59
Fixed income
Mortgage-backed securities	—				63				—			63
U.S. government securities	—				54				—			54
Other fixed-income securities (1)	40				196				—			236
Equity securities
Domestic	313				109				—			422
International	112				238				—			350
Other
Real estate	—				46				78			124
Private equity	—				—				64			64
Hedge funds and other alternative strategies	20				—				77			97
Total investments (2)	$	508			$	742			$	219		$	1,469
Liabilities
Hedge funds and other alternative strategies	$	(11	)		$	—			$	—		$	(11	)
Total liabilities	$	(11	)		$	—			$	—		$	(11	)
__________________________________________________________________
(1)	Amounts include investments in diversified fixed-income collective investment funds with exposure to mortgage-backed securities, government-issued securities, corporate debt, and other fixed-income securities.
(2)	Amount excludes net receivables of $2 million for 2013 and $4 million for 2012, primarily related to Level 1 investments.
22. Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans (Continued)
Investments in securities traded in active markets are measured based on quoted prices, which represent Level 1 inputs. Investments based on Level 2 inputs include direct investments in corporate debt and other fixed-income securities, as well as shares of open-end mutual funds or similar investment vehicles that do not have a readily determinable fair value, but are valued at the net asset value per share (NAV). For such funds, the NAV is the value at which investors transact with the fund, and is determined by the fund based on the estimated fair values of the underlying fund assets. Fair value of investments included as Level 3 inputs generally also reflect investments valued at fund NAVs, but, unlike investments characteristic of Level 2 fair-value measurements, such plan assets have significant liquidity restrictions or other features that are not reflected in NAV.
The following summarizes changes in the fair value of investments based on Level 3 inputs:
millions	Hedge Funds				Private				Real Estate			Total
	and Other				Equity
	Alternative
	Strategies
Balance at January 1, 2012	$	64			$	55			$	72		$	191
Acquisitions (dispositions), net	9				4				2			15
Actual return on plan assets
Relating to assets sold during the reporting period	(2		)		2				—			—
Relating to assets still held at the reporting date	6				3				4			13
Balance at December 31, 2012	$	77			$	64			$	78		$	219
Acquisitions (dispositions), net	(6		)		—				2			(4		)
Actual return on plan assets
Relating to assets sold during the reporting period	1				4				—			5
Relating to assets still held at the reporting date	7				4				6			17
Balance at December 31, 2013	$	79			$	72			$	86		$	237
Risks and Uncertainties  The plan assets include various investment securities that are exposed to various risks, such as interest-rate, credit, and market risks. Due to the level of risk associated with certain investment securities, it is possible that changes in the values of investment securities could significantly impact the plan assets.
The plan assets may include securities with contractual cash flows, such as asset-backed securities, collateralized mortgage obligations, and commercial mortgage-backed securities, including securities backed by subprime mortgage loans. The value, liquidity, and related income of those securities are sensitive to changes in economic conditions, including real estate value, delinquencies, or defaults, or both, and may be adversely affected by shifts in the market’s perception of the issuers and changes in interest rates.
22. Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans (Continued)
Expected Benefit Payments
The following summarizes estimated benefit payments for the next ten years, including benefit increases due to continuing employee service:
millions	Pension				Other
	Benefit				Benefit
	Payments				Payments
2014	$	139			$	15
2015	148				16
2016	163				16
2017	185				17
2018	181				18
2019-2023	1,065				98
Defined-Contribution Plans  The Company maintains several defined-contribution benefit plans, the most significant of which is the Anadarko Employee Savings Plan (ESP). All regular employees of the Company on its U.S. payroll are eligible to participate in the ESP by making elective contributions that are matched by the Company, subject to certain limitations. The Company recognized expense of $78 million for 2013, $55 million for 2012, and $41 million for 2011, related to these plans.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Policy Text Block [Abstract]	'
Consolidation	'
	Basis of Presentation  The Consolidated Financial Statements have been prepared in conformity with accounting principles generally accepted in the United States. The Consolidated Financial Statements include the accounts of Anadarko and entities in which it holds a controlling interest. All intercompany transactions have been eliminated. Undivided interests in oil and natural-gas exploration and production joint ventures are consolidated on a proportionate basis. Investments in non-controlled entities, over which Anadarko has the ability to exercise significant influence over operating and financial policies, are accounted for using the equity method. In applying the equity method of accounting, the investments are initially recognized at cost, and subsequently adjusted for the Company’s proportionate share of earnings, losses, and distributions. Other investments are carried at original cost. Investments accounted for using the equity method and cost method are reported as a component of other assets. Certain prior-period amounts have been reclassified to conform to the current-year presentation.
Use of Estimates	'
	Use of Estimates  The preparation of financial statements in accordance with accounting principles generally accepted in the United States requires management to make informed judgments and estimates that affect the reported amounts of assets, liabilities, revenues, and expenses. Management evaluates its estimates and related assumptions regularly, including those related to proved reserves; the value of properties and equipment; goodwill; intangible assets; asset retirement obligations; litigation liabilities; environmental liabilities; pension assets, liabilities, and costs; income taxes; and fair values. Changes in facts and circumstances or additional information may result in revised estimates, and actual results may differ from these estimates.
Fair Value	'
	Fair Value  Fair value is defined as the price that would be received to sell an asset or the price paid to transfer a liability in an orderly transaction between market participants at the measurement date. Inputs used in determining fair value are characterized according to a hierarchy that prioritizes those inputs based on the degree to which they are observable. The three input levels of the fair-value hierarchy are as follows:
	Level 1—Inputs represent quoted prices in active markets for identical assets or liabilities (for example, exchange-traded commodity derivatives).
	Level 2—Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly (for example, quoted market prices for similar assets or liabilities in active markets or quoted market prices for identical assets or liabilities in markets not considered to be active, inputs other than quoted prices that are observable for the asset or liability, or market-corroborated inputs).
	Level 3—Inputs that are not observable from objective sources, such as the Company’s internally developed assumptions used in pricing an asset or liability (for example, an estimate of future cash flows used in the Company’s internally developed present value of future cash flows model that underlies the fair-value measurement).
	In determining fair value, the Company uses observable market data when available, or models that incorporate observable market data. In addition to market information, the Company incorporates transaction-specific details that, in management’s judgment, market participants would take into account in measuring fair value.
	1. Summary of Significant Accounting Policies (Continued)
	In arriving at fair-value estimates, the Company uses the most observable inputs available for the valuation technique employed. If a fair-value measurement reflects inputs at multiple levels within the hierarchy, the fair-value measurement is characterized based on the lowest level of input that is significant to the fair-value measurement. For Anadarko, recurring fair-value measurements are performed for interest-rate derivatives, commodity derivatives, and investments in trading securities.
	The carrying amount of cash and cash equivalents, accounts receivable, and accounts payable reported on the Consolidated Balance Sheets approximates fair value. The fair value of debt is the estimated amount the Company would have to pay to repurchase its debt, including any premium or discount attributable to the difference between the stated interest rate and market interest rate at each balance sheet date. Debt fair values, as disclosed in Note 12—Debt and Interest Expense, are based on quoted market prices for identical instruments, if available, or based on valuations of similar debt instruments.
	Non-financial assets and liabilities initially measured at fair value include certain assets and liabilities acquired in a business combination or through a non-monetary exchange transaction, intangible assets, goodwill, asset retirement obligations, exit or disposal costs, and capital lease assets where the present value of lease payments is greater than the fair value of the leased asset.
Revenues	'
	Revenues  The Company’s natural gas is sold primarily to interstate and intrastate natural-gas pipelines, direct end-users, industrial users, local distribution companies, and natural-gas marketers. Oil and condensate are sold primarily to marketers, gatherers, and refiners. NGLs are sold primarily to direct end-users, refiners, and marketers.
	The Company recognizes sales revenues for natural gas, oil and condensate, and NGLs based on the amount of each product sold to purchasers when delivery to the purchaser has occurred and title has transferred. This occurs when product has been delivered to a pipeline or when a tanker lifting has occurred. The Company follows the sales method of accounting for natural-gas production imbalances. If the Company’s sales volumes for a well exceed the Company’s proportionate share of production from the well, a liability is recognized to the extent that the Company’s share of estimated remaining recoverable reserves from the well is insufficient to satisfy this imbalance. No receivables are recorded for those wells on which the Company has taken less than its proportionate share of production.
	Anadarko provides gathering, processing, treating, and transporting services pursuant to a variety of contracts. Under these arrangements, the Company receives fees, or retains a percentage of products or a percentage of the proceeds from the sale of products and recognizes revenue at the time the services are performed or product is sold. These revenues are included in gathering, processing, and marketing sales in the Consolidated Statements of Income.
	Marketing margins related to the Company’s production are included in natural-gas sales, oil and condensate sales, and NGLs sales. Marketing margins related to sales of commodities purchased from third parties and gains and losses on derivatives related to such marketing activities are included in gathering, processing, and marketing sales in the Consolidated Statements of Income.
	The Company enters into buy/sell arrangements related to the transportation of a portion of its crude-oil production. Under these arrangements, barrels are sold to a third party at a location-based contract price and subsequently repurchased by the Company at a downstream location. The difference in value between the sale and purchase price represents the transportation fee from the lease or certain gathering locations to more liquid markets. These arrangements are often required by private transporters. These transactions are reported on a net basis and included in oil and gas transportation in the Consolidated Statements of Income.
Cash Equivalents	'
	Cash Equivalents  The Company considers all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents.
Accounts Receivable and Allowance for Uncollectible Accounts	'
	Accounts Receivable and Allowance for Uncollectible Accounts  The Company conducts credit analyses of customers prior to making any sales to new customers or increasing credit for existing customers. Based on these analyses, the Company may require a standby letter of credit or a financial guarantee. The Company charges uncollectible accounts receivable against the allowance for uncollectible accounts when it determines collection will no longer be pursued.
Inventories	'
	Inventories  Commodity inventories are stated at the lower of average cost or market.
Properties and Equipment	'
	Properties and Equipment  Properties and equipment are stated at cost less accumulated depreciation, depletion, and amortization expense (DD&A). Costs of improvements that appreciably improve the efficiency or productive capacity of existing properties or extend their lives are capitalized. Maintenance and repairs are expensed as incurred. Upon retirement or sale, the cost of properties and equipment, net of the related accumulated DD&A, is removed and, if appropriate, gain or loss is recognized in gains (losses) on divestitures and other, net.
Oil and Gas Properties	'
	Oil and Gas Properties  The Company applies the successful efforts method of accounting for oil and gas properties. Exploration costs such as exploratory geological and geophysical costs, delay rentals, and exploration overhead are charged against earnings as incurred. If an exploratory well provides evidence to justify potential completion as a producing well, drilling costs associated with the well are initially capitalized, or suspended, pending a determination as to whether a commercially sufficient quantity of proved reserves can be attributed to the area as a result of drilling. This determination may take longer than one year in certain areas (generally in deepwater and international locations) depending on, among other things, the amount of hydrocarbons discovered, the outcome of planned geological and engineering studies, the need for additional appraisal drilling activities to determine whether the discovery is sufficient to support an economic development plan, and government sanctioning of development activities in certain international locations. At the end of each quarter, management reviews the status of all suspended exploratory well costs in light of ongoing exploration activities—in particular, whether the Company is making sufficient progress in its ongoing exploration and appraisal efforts or, in the case of discoveries requiring government sanctioning, whether development negotiations are underway and proceeding as planned. If management determines that future appraisal drilling or development activities are unlikely to occur, associated suspended exploratory well costs are expensed.
	Acquisition costs of unproved properties are periodically assessed for impairment and are transferred to proved oil and gas properties to the extent the costs are associated with successful exploration activities. Significant undeveloped leases are assessed individually for impairment, based on the Company’s current exploration plans, and a valuation allowance is provided if impairment is indicated. Unproved oil and gas properties with individually insignificant lease acquisition costs are amortized on a group basis (thereby establishing a valuation allowance) over the average lease term at rates that provide for full amortization of unsuccessful leases upon lease expiration or abandonment. Costs of expired or abandoned leases are charged against the valuation allowance, while costs of productive leases are transferred to proved oil and gas properties. Costs of maintaining and retaining unproved properties, as well as amortization of individually insignificant leases and impairment of unsuccessful leases, are included in exploration expense in the Consolidated Statements of Income.
Capitalized Interest	'
	Capitalized Interest  For significant projects, interest is capitalized as part of the historical cost of developing and constructing assets. Significant oil and gas investments in unproved properties, significant exploration and development projects that have not commenced production, significant midstream development activities that are in progress, and investments in equity method affiliates that are undergoing the construction of assets that have not commenced principle operations qualify for interest capitalization. Interest is capitalized until the asset is ready for service. Capitalized interest is determined by multiplying the Company’s weighted-average borrowing cost on debt by the average amount of qualifying costs incurred. Once an asset subject to interest capitalization is completed and placed in service, the associated capitalized interest is expensed through depreciation or impairment. See Note 12—Debt and Interest Expense.
Asset Retirement Obligations	'
	Asset Retirement Obligations  Asset retirement obligations (AROs) associated with the retirement of tangible long-lived assets are recognized as liabilities with an increase to the carrying amounts of the related long-lived assets in the period incurred. The cost of the tangible asset, including the asset retirement cost, is depreciated over the useful life of the asset. AROs are recorded at estimated fair value, measured by reference to the expected future cash outflows required to satisfy the retirement obligations discounted at the Company’s credit-adjusted risk-free interest rate. Accretion expense is recognized over time as the discounted liabilities are accreted to their expected settlement value. If estimated future costs of AROs change, an adjustment is recorded to both the asset retirement obligation and the long-lived asset. Revisions to estimated AROs can result from changes in retirement cost estimates, revisions to estimated inflation rates, and changes in the estimated timing of abandonment. See Note 7—Asset Retirement Obligations.
Impairments	'
	Impairments  Properties and equipment are reviewed for impairment when facts and circumstances indicate that net book values may not be recoverable. In performing this review, an undiscounted cash flow test is performed at the lowest level for which identifiable cash flows are independent of cash flows from other assets. If the sum of the undiscounted future net cash flows is less than the net book value of the property, an impairment loss is recognized for the excess, if any, of the property’s net book value over its estimated fair value. See Note 5—Impairments.
Depreciation, Depletion, and Amortization	'
	Depreciation, Depletion, and Amortization  Costs of drilling and equipping successful wells, costs to construct or acquire facilities other than offshore platforms, associated asset retirement costs, and capital lease assets used in oil and gas activities are depreciated using the unit-of-production (UOP) method based on total estimated proved developed oil and gas reserves. Costs of acquiring proved properties, including leasehold acquisition costs transferred from unproved properties and costs to construct or acquire offshore platforms and associated asset retirement costs, are depleted using the UOP method based on total estimated proved developed and undeveloped reserves. Mineral properties are also depleted using the UOP method. All other properties are stated at historical acquisition cost, net of impairments, and are depreciated using the straight-line method over the useful lives of the assets, which range from 3 to 15 years for furniture and equipment, up to 40 years for buildings, and up to 47 years for gathering facilities.
Goodwill	'
	Goodwill is subject to annual impairment testing at October 1 (or more frequent testing as circumstances dictate). Anadarko has allocated goodwill to the following reporting units: oil and gas exploration and production, other gathering and processing, Western Gas Partners, LP (WES) gathering and processing, and transportation. Changes in goodwill may result from, among other things, impairments, future acquisitions, or future divestitures. See Note 8—Goodwill and Other Intangible Assets.
Other Intangible Assets	'
	Other intangible assets represent contractual rights obtained in connection with business combinations that had favorable contractual terms relative to market at the acquisition date. Other intangible assets are amortized over their estimated useful lives and are assessed for impairment whenever impairment indicators are present. See Note 8—Goodwill and Other Intangible Assets.
Derivative Instruments	'
	Derivative Instruments  Anadarko uses derivative instruments to manage its exposure to cash-flow variability from commodity-price and interest-rate risk. Derivatives are carried on the balance sheet at fair value and are included in other current assets, other assets, accrued expenses, or other long-term liabilities, depending on the derivative position and the expected timing of settlement, unless they satisfy the normal purchases and sales exception criteria. Where the Company has the contractual right and intends to net settle, derivative assets and liabilities are reported on a net basis.
	Gains and losses on derivative instruments are recognized currently in earnings. Net losses attributable to derivatives previously subject to hedge accounting reside in accumulated other comprehensive income and will be reclassified to earnings in future periods as the economic transactions to which the derivatives relate affect earnings. See Note 11—Derivative Instruments.
Legal Contingencies	'
	Legal Contingencies  The Company is subject to legal proceedings, claims, and liabilities that arise in the ordinary course of business. Except for legal contingencies acquired in a business combination, which are recorded at fair value at the time of acquisition, the Company accrues losses associated with legal claims when such losses are probable and reasonably estimable. If the Company determines that a loss is probable and cannot estimate a specific amount for that loss, but can estimate a range of loss, the best estimate within the range is accrued. If no amount within the range is a better estimate than any other, the minimum amount of the range is accrued. Estimates are adjusted as additional information becomes available or circumstances change. Legal defense costs associated with loss contingencies are expensed in the period incurred. See Note 17—Contingencies.
Environmental Contingencies	'
	Environmental Contingencies  The Company is subject to various environmental-remediation and reclamation obligations arising from federal, state, and local laws and regulations. Except for environmental contingencies acquired in a business combination, which are recorded at fair value at the time of acquisition, the Company accrues losses associated with environmental obligations when such losses are probable and reasonably estimable. Accruals for estimated environmental losses are recognized no later than at the time the remediation feasibility study, or the evaluation of response options, is complete. These accruals are adjusted as additional information becomes available or circumstances change. Future environmental expenditures are not discounted to their present value. Recoveries of environmental costs from other parties are recorded separately as assets at their undiscounted value when receipt of such recoveries is probable. See Note 17—Contingencies.
Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans	'
	Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans  The Company measures pension plan assets at fair value. Defined-benefit plan obligations and costs are actuarially determined, incorporating the use of various assumptions. Critical assumptions for pension and other postretirement plans include the discount rate, the expected long-term rate of return on plan assets (for funded pension plans), the rate of future compensation increases, and the health care cost trend rate (for postretirement plans). Other assumptions involve demographic factors such as retirement age, mortality, and turnover. The Company evaluates and updates its actuarial assumptions at least annually.
	The Company amortizes prior service costs (credits) on a straight-line basis over the average remaining service period of employees expected to receive benefits under each plan. Actuarial gains and losses that exceed 10% of the greater of the projected benefit obligation and the market-related value of assets are amortized over the average remaining service period of participating employees expected to receive benefits under each plan. See Note 22—Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans.
	Accumulated and projected benefit obligations are measured as the present value of future cash payments. The Company discounts those cash payments using a discount rate that reflects the weighted average of market-observed yields for select high-quality (AA-rated) fixed-income securities with cash flows that correspond to the expected amounts and timing of benefit payments. The discount-rate assumption used by the Company represents an estimate of the interest rate at which the pension and other postretirement benefit obligations could effectively be settled on the measurement date.
	Investment Policies and Strategies  The Company has adopted a balanced, diversified investment strategy, with the intent of maximizing returns without exposure to undue risk. Investments are typically made through investment managers across several investment categories (domestic equity securities, international equity securities, fixed-income securities, real estate, hedge funds, and private equity), with selective exposure to Growth/Value investment styles. Performance for each investment is measured relative to the appropriate index benchmark for its category. Target asset-allocation percentages by major category are 45%-55% equity securities, 20%-30% fixed income, and up to 25% in a combination of other investments such as real estate, hedge funds, and private equity. Investment managers have full discretion as to investment decisions regarding funds under their management to the extent permitted within investment guidelines.
	Although investment managers may, at their discretion and within investment guidelines, invest in Anadarko securities, there are no direct investments in Anadarko securities included in plan assets. There may be, however, indirect investments in Anadarko securities through the plans’ collective fund investments. The expected long-term rate of return on plan assets assumption was determined using the year-end 2013 pension investment balances by asset class and expected long-term asset allocation. The expected return for each asset class reflects capital-market projections formulated using a forward-looking building-block approach, while also taking into account historical return trends and current market conditions. Equity returns generally reflect long-term expectations of real earnings growth, dividend yield, and inflation. Returns on fixed-income securities are generally developed based on expected inflation, real bond yield, and risk spread (as appropriate), adjusted for the expected effect that changing yields have on the rate of return. Other asset-class returns are derived from their relationship to the equity and fixed-income markets.
Income Taxes	'
	Income Taxes  The Company files various U.S. federal, state, and foreign income tax returns. Deferred federal, state, and foreign income taxes are provided on temporary differences between the financial statement carrying amounts of assets and liabilities and their respective tax basis. The Company routinely assesses the realizability of its deferred tax assets. If the Company concludes that it is more likely than not that some of the deferred tax assets will not be realized, the tax asset is reduced by a valuation allowance. The Company recognizes a tax benefit from an uncertain tax position when it is more likely than not that the position will be sustained upon examination, based on the technical merits of the position. The tax benefit recorded is equal to the largest amount that is greater than 50% likely to be realized through final settlement with a taxing authority. Interest and penalties related to unrecognized tax benefits are recognized in income tax expense (benefit). See Note 19—Income Taxes.
Share-Based Compensation	'
	Share-Based Compensation  The Company accounts for share-based compensation at fair value. The Company grants equity-classified awards including stock options and non-vested equity shares (restricted stock awards and units). The Company may also grant equity-classified and liability-classified awards based on a comparison of the Company’s total shareholder return (TSR) to the TSR of a predetermined group of peer companies (performance units).
	The fair value of stock option awards is determined using the Black-Scholes option-pricing model. Restricted stock awards and units are valued using the market price of Anadarko common stock. For other share-based compensation awards, fair value is determined using a Monte Carlo simulation or discounted-cash-flow methodology.
	The Company records compensation cost, net of estimated forfeitures, for share-based compensation awards over the requisite service period using the straight-line method. An adjustment is made to compensation cost for any difference between the estimated forfeitures and the actual forfeitures related to the awards. For equity-classified share-based compensation awards, expense is recognized based on the grant-date fair value. For liability-classified share-based compensation awards, expense is recognized for those awards expected to ultimately be paid. The amount of expense reported is adjusted for fair-value changes so that the expense recognized for each award is equivalent to the amount to be paid. See Note 15—Share-Based Compensation.
Earnings Per Share	'
	Earnings Per Share  The Company’s basic earnings per share (EPS) is computed based on the average number of shares of common stock outstanding for the period and includes the effect of any participating securities as appropriate. Diluted EPS includes the effect of the Company’s outstanding stock options, restricted stock awards, restricted stock units, and performance-based stock awards, if the inclusion of these items is dilutive. See Note 13—Stockholders’ Equity.

Pension_Plans_Other_Postretire1

Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans (Policies)	12 Months Ended
	Dec. 31, 2013
Disclosure Text Block [Abstract]	'
Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans	'
	Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans  The Company measures pension plan assets at fair value. Defined-benefit plan obligations and costs are actuarially determined, incorporating the use of various assumptions. Critical assumptions for pension and other postretirement plans include the discount rate, the expected long-term rate of return on plan assets (for funded pension plans), the rate of future compensation increases, and the health care cost trend rate (for postretirement plans). Other assumptions involve demographic factors such as retirement age, mortality, and turnover. The Company evaluates and updates its actuarial assumptions at least annually.
	The Company amortizes prior service costs (credits) on a straight-line basis over the average remaining service period of employees expected to receive benefits under each plan. Actuarial gains and losses that exceed 10% of the greater of the projected benefit obligation and the market-related value of assets are amortized over the average remaining service period of participating employees expected to receive benefits under each plan. See Note 22—Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans.
	Accumulated and projected benefit obligations are measured as the present value of future cash payments. The Company discounts those cash payments using a discount rate that reflects the weighted average of market-observed yields for select high-quality (AA-rated) fixed-income securities with cash flows that correspond to the expected amounts and timing of benefit payments. The discount-rate assumption used by the Company represents an estimate of the interest rate at which the pension and other postretirement benefit obligations could effectively be settled on the measurement date.
	Investment Policies and Strategies  The Company has adopted a balanced, diversified investment strategy, with the intent of maximizing returns without exposure to undue risk. Investments are typically made through investment managers across several investment categories (domestic equity securities, international equity securities, fixed-income securities, real estate, hedge funds, and private equity), with selective exposure to Growth/Value investment styles. Performance for each investment is measured relative to the appropriate index benchmark for its category. Target asset-allocation percentages by major category are 45%-55% equity securities, 20%-30% fixed income, and up to 25% in a combination of other investments such as real estate, hedge funds, and private equity. Investment managers have full discretion as to investment decisions regarding funds under their management to the extent permitted within investment guidelines.
	Although investment managers may, at their discretion and within investment guidelines, invest in Anadarko securities, there are no direct investments in Anadarko securities included in plan assets. There may be, however, indirect investments in Anadarko securities through the plans’ collective fund investments. The expected long-term rate of return on plan assets assumption was determined using the year-end 2013 pension investment balances by asset class and expected long-term asset allocation. The expected return for each asset class reflects capital-market projections formulated using a forward-looking building-block approach, while also taking into account historical return trends and current market conditions. Equity returns generally reflect long-term expectations of real earnings growth, dividend yield, and inflation. Returns on fixed-income securities are generally developed based on expected inflation, real bond yield, and risk spread (as appropriate), adjusted for the expected effect that changing yields have on the rate of return. Other asset-class returns are derived from their relationship to the equity and fixed-income markets.

Acquisitions_Divestitures_and_1

Acquisitions, Divestitures, and Assets Held for Sale (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Acquisitions Table	'
	The following summarizes acquisitions made during 2013 and 2011. There were no acquisitions made during 2012.
	millions, except percentages		Percentage		Cash Paid
			Acquired
	2013
	Certain oil and gas properties and related assets in the Moxa area of Wyoming		100	%	$	310	(1)
	Gas-gathering systems in the Marcellus shale in north-central Pennsylvania		33.75	%	135
	Joint venture formed to design, construct, and own two fractionators located in		25	%	78
	Mont Belvieu, Texas
	Intrastate pipeline in southwestern Wyoming		100	%	28
	2011
	Natural-gas processing plant and related gathering systems in northeast Colorado		100	%	302
	Natural-gas processing plant (Wattenberg Plant) in northeast Colorado		93	%	500		(2)
	__________________________________________________________________
	-1	Includes $306 million that represents the fair value of the oil and gas properties acquired.
	(2)	The Company recognized a $76 million loss on preexisting contracts with the previous Wattenberg Plant owner in addition to the cash paid in the Wattenberg Plant acquisition. Anadarko operates and owns a 100% interest in the Wattenberg Plant.

Inventories_Tables

Inventories (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Inventory Disclosure Table	'
	The following summarizes the major classes of inventories, included in other current assets, at December 31:
	millions	2013		2012
	Crude oil	$	88	$	91
	Natural gas	43		48
	NGLs	79		37
	Total	$	210	$	176

Properties_and_Equipment_Table

Properties and Equipment (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Cost of Properties and Equipment by Segment Table	'
	The following summarizes the cost of properties and equipment by segment at December 31:
	millions	2013		2012
	Oil and gas exploration and production (1)	$	61,302	$	55,180
	Midstream	7,285		6,032
	Marketing	9		9
	Other	2,648		2,377
	Total	$	71,244	$	63,598
	__________________________________________________________________
	(1)	Includes costs associated with unproved properties of $6.9 billion at December 31, 2013, and $7.1 billion at December 31, 2012.

Impairments_Tables

Impairments (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Schedule of Impairment Expense	'
	The following summarizes impairments by segment for the years ended December 31:
	millions	2013			2012			2011
	Oil and gas exploration and production
	Long-lived assets held for use
	U.S. onshore properties	$	142		$	259		$	1,063
	Gulf of Mexico properties	562			104			162
	Cost-method investment	11			13			91
	Midstream
	Long-lived assets held for use	79			13			458
	Impairments	$	794		$	389		$	1,774
Nonrecurring Fair Value Measurements Table	'
	The following summarizes the post-impairment fair value of the above-described assets, all of which were measured using the income approach and Level 3 inputs:
	millions		2013			2012
	Long-lived assets held for use		$	548		$	103
	Cost-method investment (1)		32			34
	__________________________________________________________________
	(1)	This represents the Company’s after-tax net investment.

Suspended_Exploratory_Well_Cos1

Suspended Exploratory Well Costs (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Suspended Exploratory Well Costs Roll Forward	'
	The following summarizes the changes in suspended exploratory well costs at December 31 for each of the last three years. Additions pending the determination of proved reserves excludes amounts capitalized and subsequently charged to expense within the same year.
	millions	2013			2012			2011
	Balance at January 1	$	2,062		$	1,353		$	935
	Additions pending the determination of proved reserves	848			960			572
	Divestitures	(48		)	—			—
	Reclassifications to proved properties	(507		)	(129		)	(116		)
	Charges to exploration expense	(123		)	(122		)	(38		)
	Balance at December 31	$	2,232		$	2,062		$	1,353
Schedule of Aging of Suspended Exploratory Well Costs by Geographic Area	'
	The following summarizes an aging of suspended exploratory well costs by geographic area and the year the costs were suspended at December 31, 2013:
					Year Costs Incurred
	millions	Total			2013(1)			2012			2011		2010 and
													prior
	United States—Onshore	$	160		$	143		$	6		$	1	$	10
	United States—Offshore	461			126			137			24		174
	International	1,611			442			526			303		340
		$	2,232		$	711		$	669		$	328	$	524
	__________________________________________________________________
	(1)	Excludes additions subsequently reclassified to proved properties within the same year.

Asset_Retirement_Obligations_T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Asset Retirement Obligations Rollforward	'
	The following summarizes changes in the Company’s AROs during 2013 and 2012:
	millions	2013			2012
	Carrying amount of asset retirement obligations at January 1	$	1,885		$	1,768
	Liabilities incurred	182			70
	Property dispositions	(76		)	(78		)
	Liabilities settled	(162		)	(89		)
	Accretion expense	110			110
	Revisions in estimated liabilities	83			104
	Carrying amount of asset retirement obligations at December 31	$	2,022		$	1,885

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Other Intangible Assets	'
	Intangible assets and associated amortization expense were as follows:
	millions	Gross Carrying		Accumulated			Net Carrying		Amortization
		Amount		Amortization			Amount		Expense
	December 31, 2013
	Offshore platform leases	$	60	$	(50	)	$	10	$	3
	Customer contracts	169		(9		)	160		4
		$	229	$	(59	)	$	170	$	7
	December 31, 2012
	Offshore platform leases	$	60	$	(36	)	$	24	$	3
	Customer contracts	169		(5		)	164		3
		$	229	$	(41	)	$	188	$	6

Derivative_Instruments_Tables

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Schedule of Derivative Instruments	'
	The following is a summary of the Company’s derivative instruments related to its Oil and Natural-Gas Production/Processing Activities at December 31, 2013:
			2014				2015
			Settlement				Settlement
	Natural Gas
	Three-Way Collars (thousand MMBtu/d)		600				635
	Average price per MMBtu
	Ceiling sold price (call)		$	5.01			$	4.76
	Floor purchased price (put)		$	3.75			$	3.75
	Floor sold price (put)		$	2.75			$	2.75
	Fixed-Price Contracts (thousand MMBtu/d)		600				—
	Average price per MMBtu		$	4.26			$	—
	Extendable Fixed-Price Contracts (thousand MMBtu/d) (1)		400				—
	Average price per MMBtu		$	4.19			$	—
	Crude Oil
	Fixed-Price Contracts (MBbls/d)		107				—
	Average price per barrel		$	100.58			$	—
	__________________________________________________________________
	-1	The extendable fixed-price contracts have a contract term of January 2014 to June 2014 with an option to extend the contract term to December 2014 at the same price.
	MMBtu—million British thermal units
	MMBtu/d—million British thermal units per day
	MBbls/d—thousand barrels per day
	The Company had the following outstanding interest-rate swaps at December 31, 2013:
	millions except percentages					Reference Period				Weighted-Average
	Notional Principal Amount					Start		End		Interest Rate
	$	750				Jun-14		Jun-24		6.00%
	$	1,100				Jun-14		Jun-44		5.57%
	$	50				Sep-16		Sep-26		5.91%
	$	750				Sep-16		Sep-46		5.86%
Schedule of Other Derivatives Not Designated as Hedging Instruments, Statements of Financial Performance and Financial Position, Location	'
	The following summarizes the fair value of the Company’s derivative instruments at December 31:
	millions		Gross								Gross
			Derivative Assets								Derivative Liabilities
	Balance Sheet Classification		2013				2012				2013				2012
	Commodity derivatives
	Other current assets		$	181			$	475			$	(102	)		$	(197	)
	Other assets		89				24				(66		)		(7		)
	Accrued expenses		106				6				(149		)		(14		)
	Other liabilities		4				1				(15		)		(7		)
			380				506				(332		)		(225		)
	Interest-rate and other derivatives
	Accrued expenses (1)		—				—				(480		)		—
	Other liabilities (1)		—				—				(174		)		(1,194		)
			—				—				(654		)		(1,194		)
	Total derivatives		$	380			$	506			$	(986	)		$	(1,419	)
	__________________________________________________________________
	-1	Interest-rate swaps with June 2014 maturity dates were reclassified from other liabilities to accrued expenses during 2013.
	The following summarizes gains and losses related to derivative instruments:
	millions
	Classification of (Gain) Loss Recognized		2013				2012				2011
	Commodity derivatives
	Gathering, processing, and marketing sales (1)		$	6			$	18			$	8
	(Gains) losses on derivatives, net		141				(387		)		(562		)
	Interest-rate and other derivatives
	(Gains) losses on derivatives, net		(539		)		61				1,023
	Total (gains) losses on derivatives, net		$	(392	)		$	(308	)		$	469
	__________________________________________________________________
	-1	Represents the effect of marketing and trading derivative activities.
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	'
	The following summarizes the fair value of the Company’s derivative assets and liabilities, by input level within the fair-value hierarchy:
	millions	Level 1				Level 2				Level 3				Netting (1)				Collateral		Total
	December 31, 2013
	Assets
	Commodity derivatives
	Financial institutions	$	—			$	211			$	—			$	(153	)		$	—	$	58
	Other counterparties	—				169				—				(126		)		—		43
	Total derivative assets	$	—			$	380			$	—			$	(279	)		$	—	$	101
	Liabilities
	Commodity derivatives
	Financial institutions	$	—			$	(200	)		$	—			$	153			$	7	$	(40	)
	Other counterparties	—				(132		)		—				126				—		(6		)
	Interest-rate and other derivatives	—				(654		)		—				—				—		(654		)
	Total derivative liabilities	$	—			$	(986	)		$	—			$	279			$	7	$	(700	)
	December 31, 2012
	Assets
	Commodity derivatives
	Financial institutions	$	6			$	453			$	—			$	(206	)		$	—	$	253
	Other counterparties	—				47				—				(5		)		—		42
	Total derivative assets	$	6			$	500			$	—			$	(211	)		$	—	$	295
	Liabilities
	Commodity derivatives
	Financial institutions	$	(6	)		$	(202	)		$	—			$	206			$	1	$	(1	)
	Other counterparties	—				(17		)		—				5				—		(12		)
	Interest-rate and other derivatives	—				(1,194		)		—				—				—		(1,194		)
	Total derivative liabilities	$	(6	)		$	(1,413	)		$	—			$	211			$	1	$	(1,207	)
	__________________________________________________________________
	(1)	Represents the impact of netting commodity derivative assets and liabilities with counterparties where the Company has the contractual right and intends to net settle.

Debt_and_Interest_Expense_Tabl

Debt and Interest Expense (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Debt Outstanding and Debt Activity Tables	'
	The following summarizes the Company’s outstanding debt:
		December 31,
	millions	2013			2012
	5.750% Senior Notes due 2014	$	275		$	275
	7.625% Senior Notes due 2014	500			500
	5.950% Senior Notes due 2016	1,750			1,750
	6.375% Senior Notes due 2017	2,000			2,000
	7.050% Debentures due 2018	114			114
	WES 2.600% Senior Notes due 2018	250			—
	6.950% Senior Notes due 2019	300			300
	8.700% Senior Notes due 2019	600			600
	WES 5.375% Senior Notes due 2021	500			500
	WES 4.000% Senior Notes due 2022	670			670
	6.950% Senior Notes due 2024	650			650
	7.500% Debentures due 2026	112			112
	7.000% Debentures due 2027	54			54
	7.125% Debentures due 2027	150			150
	6.625% Debentures due 2028	17			17
	7.150% Debentures due 2028	235			235
	7.200% Debentures due 2029	135			135
	7.950% Debentures due 2029	117			117
	7.500% Senior Notes due 2031	900			900
	7.875% Senior Notes due 2031	500			500
	Zero-Coupon Senior Notes due 2036	2,360			2,360
	6.450% Senior Notes due 2036	1,750			1,750
	7.950% Senior Notes due 2039	325			325
	6.200% Senior Notes due 2040	750			750
	7.730% Debentures due 2096	61			61
	7.500% Debentures due 2096	78			78
	7.250% Debentures due 2096	49			49
	Total debt at face value	$	15,202		$	14,952
	Net unamortized discounts and premiums (1)	(1,645		)	(1,683		)
	Total borrowings	$	13,557		$	13,269
	Capital lease obligation	8			—
	Less current portion of long-term debt	500			—
	Total long-term debt	$	13,065		$	13,269
	__________________________________________________________________
	-1	Unamortized discounts and premiums are amortized over the term of the related debt.
	The following summarizes the Company’s debt activity during 2013 and 2012:
	millions	Carrying			Description
		Value
	Balance at December 31, 2011	$	15,230
	Issuances	674			WES 4.000% Senior Notes due 2022
	Borrowings	374			WES revolving credit facility
	Repayments	(131		)	6.125% Senior Notes due 2012
		(39		)	5.000% Senior Notes due 2012
		(374		)	WES revolving credit facility
		(2,500		)	$5.0 billion Facility
	Other, net	35			Amortization of debt discounts and premiums
	Balance at December 31, 2012	$	13,269
	Issuances	250			WES 2.600% Senior Notes due 2018
	Borrowings	710			WES revolving credit facility
	Repayments	(710		)	WES revolving credit facility
	Other, net	38			Amortization of debt discounts and premiums
	Balance at December 31, 2013	$	13,557
Scheduled Maturities Table	'
	Total principal amount of debt maturities for the five years ending December 31, 2018, excluding the potential repayment of the outstanding Zero Coupons that may be put by the holder to the Company annually, were as follows:
	millions	Principal
		Amount of
		Debt Maturities
	2014	$	775
	2015	—
	2016	1,750
	2017	2,000
	2018	364
Interest Expense Table	'
	The following summarizes interest expense for the years ended December 31:
	millions	2013			2012			2011
	Current debt, long-term debt, and other	$	949		$	963		$	986
	Capitalized interest	(263		)	(221		)	(147		)
	Interest expense	$	686		$	742		$	839

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Common Stock Rollforward	'
	The following summarizes the changes in the Company’s outstanding shares of common stock:
	millions	2013		2012			2011
	Shares of common stock issued
	Shares at January 1	519		516			513
	Exercise of stock options	2		1			1
	Issuance of restricted stock	2		2			2
	Shares at December 31	523		519			516
	Shares of common stock held in treasury
	Shares at January 1	18		18			17
	Shares received for restricted stock vested and options exercised	1		—			1
	Shares at December 31	19		18			18
	Shares of common stock outstanding at December 31	504		501			498
Earnings Per Share Table	'
	The following provides a reconciliation between basic and diluted EPS attributable to common stockholders for the years ended December 31:
	millions except per-share amounts	2013			2012			2011
	Net income (loss)
	Net income (loss) attributable to common stockholders	$	801		$	2,391		$	(2,649	)
	Less distributions on participating securities	2			1			—
	Less undistributed income allocated to participating securities	4			14			—
	Basic	$	795		$	2,376		$	(2,649	)
	Diluted	$	795		$	2,376		$	(2,649	)
	Shares
	Average number of common shares outstanding—basic	502			500			498
	Dilutive effect of stock options	3			2			—
	Average number of common shares outstanding—diluted	505			502			498
	Excluded (1)	4			6			12
	Net income (loss) per common share
	Basic	$	1.58		$	4.76		$	(5.32	)
	Diluted	$	1.58		$	4.74		$	(5.32	)
	Dividends per common share	$	0.54		$	0.36		$	0.36
	__________________________________________________________________
	(1)	Inclusion of certain shares would have had an anti-dilutive effect.

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Schedule Of Accumulated Other Comprehensive Income (Loss) Table	'
	The following summarizes the after-tax changes in the balances of each component of accumulated other comprehensive income (loss):
	millions	Interest-rate			Pension and Other Postretirement			Total
		Derivatives			Plans
		Previously
		Subject to Hedge
		Accounting
	Balance at December 31, 2012	$	(61	)	$	(579	)	$	(640	)
	Other comprehensive income (loss), before	—			264			264
	reclassifications
	Reclassifications to Consolidated Statement of Income	7			84			91
	Net other comprehensive income (loss)	7			348			355
	Balance at December 31, 2013	$	(54	)	$	(231	)	$	(285	)

ShareBased_Compensation_Tables

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Share-Based Compensation Cost Table	'
	The following summarizes share-based compensation expense for the years ended December 31:
	millions	2013				2012				2011
	Equity-Classified Awards
	Restricted stock	$	122			$	103			$	80
	Stock options	27				43				51
	Performance-based share awards and other	1				1				1
	Total equity-classified award compensation expense	150				147				132
	Liability-Classified Awards
	Value creation plan	—				(2		)		26
	Performance-based unit awards	4				8				28
	Other performance-based awards	—				165				28
	Other	1				2				1
	Total liability-classified award compensation expense	5				173				83
	Pretax compensation expense	$	155			$	320			$	215
	Income tax benefit	$	57			$	117			$	78
Restricted Stock Activity Table	'
	The following summarizes the Company’s restricted stock activity:
		Shares			Weighted-
		(millions)			Average
					Grant-Date
					Fair Value
					(per share)
	Non-vested at January 1, 2013	2.82			$	79.27
	Granted	1.88			$	84.17
	Vested	(1.32	)		$	78.19
	Forfeited	(0.16	)		$	80.37
	Non-vested at December 31, 2013	3.22			$	82.53
Stock Option Valuation Assumptions Table	'
	The Company used the following weighted-average assumptions to estimate the fair value of stock options granted during 2013, 2012, and 2011:
		2013				2012				2011
	Expected option life—years	4.8				4.9				4.8
	Volatility	33.9		%		44.2		%		42		%
	Risk-free interest rate	1.3		%		0.7		%		1.5		%
	Dividend yield	0.8		%		0.5		%		0.5		%
Stock Option Activity Table	'
	The following summarizes the Company’s stock option activity:
		Shares			Weighted-				Weighted-		Aggregate
		(millions)			Average				Average		Intrinsic
					Exercise				Remaining		Value
					Price				Contractual		(millions)
					(per share)				Term
									(years)
	Outstanding at January 1, 2013	9.36			$	58.66
	Granted	0.91			$	91.71
	Exercised	(2.43	)		$	55.59
	Forfeited or expired	(0.12	)		$	74.55
	Outstanding at December 31, 2013	7.72			$	63.3			3.59		$	138.3
	Vested or expected to vest at December 31, 2013	7.65			$	63.14			3.57		$	138.2
	Exercisable at December 31, 2013	5.87			$	57			2.83		$	133.5

Commitments_Tables

Commitments (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Schedule of Future Minimum Lease Payments	'
	The following summarizes future minimum lease payments under operating leases at December 31, 2013:
	millions
	2014	$	964
	2015	948
	2016	755
	2017	525
	2018	309
	Later years	189
	Total future minimum lease payments	$	3,690

Contingencies_Tables

Contingencies (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Schedule Of Range Of Probable Loss	'
	The following summarizes the Company’s estimated range of probable loss:
	billions, except percentages	Low End of			High End of
		Range of			Range of
		Probable Loss			Probable Loss
	Value of Transferred Assets as of IPO date (1)	$	14.459		$	14.459
	Net Creditor Shortfall/Legacy Liabilities	(0.850		)	(4.000		)
	Allowable 502(h) Claim	$	13.609		$	10.459
	Recovery Percentage	100		%	89		%
	Offset Amount	$	13.609		$	9.309
	Value of Transferred Assets as of IPO date (1)	$	14.459		$	14.459
	Offset Amount	(13.609		)	(9.309		)
	Net Damages	$	0.85		$	5.15
	__________________________________________________________________
	-1	As determined by the Bankruptcy Court.

Other_Taxes_Tables

Other Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Other Taxes	'
	Taxes incurred, other than income taxes, for the years ended December 31 were as follows:
	millions	2013		2012		2011
	Production and severance	$	706	$	855	$	1,094
	Ad valorem	277		238		265
	Other	94		131		133
	Total	$	1,077	$	1,224	$	1,492

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Schedule of Components of Income Tax Expense (Benefit)	'
	The following summarizes components of income tax expense (benefit) for the years ended December 31:
	millions	2013				2012				2011
	Current
	Federal	$	113			$	45			$	(381	)
	State	42				25				1
	Foreign	873				891				977
		1,028				961				597
	Deferred
	Federal	94				(30		)		(1,470		)
	State	(9		)		115				(68		)
	Foreign	52				74				85
		137				159				(1,453		)
	Income tax expense (benefit)	$	1,165			$	1,120			$	(856	)
Schedule of Effective Income Tax Rate Reconciliation	'
	The following summarizes the sources of these differences for the years ended December 31:
	millions except percentages	2013				2012				2011
	Income (loss) before income taxes
	Domestic	$	428			$	132			$	(5,416	)
	Foreign	1,678				3,433				1,992
	Total	$	2,106			$	3,565			$	(3,424	)
	U.S. federal statutory tax rate	35		%		35		%		35		%
	Tax computed at the U.S. federal statutory rate	$	737			$	1,248			$	(1,198	)
	Adjustments resulting from
	State income taxes (net of federal income tax benefit)	23				93				(44		)
	Tax impact from foreign operations	167				226				93
	Non-deductible Algerian exceptional profits tax	144				188				258
	Non-taxable Algeria exceptional profits tax settlement	13				(679		)		—
	Deferred tax adjustments	76				22				5
	Non-deductible Tronox-related contingent loss	36				—				—
	Income attributable to noncontrolling interests	(48		)		(24		)		(28		)
	Items resulting from business acquisitions	—				—				19
	Other—net	17				46				39
	Income tax expense (benefit)	$	1,165			$	1,120			$	(856	)
	Effective tax rate	55		%		31		%		25		%
Deferred Tax Assets (Liabilities) Table	'
	The following summarizes components of total deferred taxes at December 31:
	millions	2013				2012
	Federal	$	(8,246	)		$	(7,890	)
	State, net of federal	(332		)		(325		)
	Foreign	(307		)		(216		)
	Total deferred taxes	$	(8,885	)		$	(8,431	)
	The following summarizes tax effects of temporary differences that give rise to significant portions of the deferred tax assets (liabilities) at December 31:
	millions	2013				2012
	Current deferred tax assets	$	412			$	328
	Valuation allowances on deferred tax assets not expected to be realized	(52		)		—
	Net current deferred tax assets	360				328
	Oil and gas exploration and development operations	(8,213		)		(8,683		)
	Mineral operations	(410		)		(408		)
	Midstream and other depreciable properties	(1,586		)		(1,295		)
	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	)
Valuation Allowances on Deferred Tax Assets Rollforwad	'
	The following summarizes changes in the balance of valuation allowances on deferred tax assets:
	millions	2013				2012				2011
	Balance at January 1	$	(922	)		$	(555	)		$	(454	)
	Additions	(38		)		(426		)		(138		)
	Reductions	142				59				37
	Balance at December 31	$	(818	)		$	(922	)		$	(555	)
Taxes Receivable (Payable) Table	'
	The following summarizes taxes receivable (payable) related to income tax expense (benefit) at December 31:
	Balance Sheet Classification		2013				2012
	Income taxes receivable
	Accounts receivable—other		$	66			$	179
	Other assets		35				2
			101				181
	Income taxes (payable)
	Accrued expense		(82		)		(38		)
	Net income taxes receivable (payable)		$	19			$	143
Schedule of Operating Loss, Tax Credit, And Other Carryforwards	'
	Tax carryforwards available for use on future income tax returns at December 31, 2013, were as follows:
	millions	Domestic				Foreign				Expiration
	Net operating loss—foreign	$	—			$	1,265			2014 - Indefinite
	Net operating loss—state	$	4,527			$	—			2014-2032
	Foreign tax credits	$	325			$	—			2015-2023
	Texas margins tax credit	$	35			$	—			2026
Unrecognized Tax Benefits Rollforward	'
	Changes in the balance of unrecognized tax benefits excluding interest and penalties on uncertain tax positions were as follows:
		Assets (Liabilities)
	millions	2013				2012				2011
	Balance at January 1	$	(46	)		$	(31	)		$	(32	)
	Increases related to prior-year tax positions	(54		)		(17		)		—
	Decreases related to prior-year tax positions	3				3				3
	Increases related to current-year tax positions	(72		)		(1		)		(10		)
	Settlements	5				—				8
	Lapse of statute of limitations	17				—				—
	Balance at December 31	$	(147	)		$	(46	)		$	(31	)
Tax Years Subject to Examination by Major Tax Jurisdiction Table	'
	The following lists the tax years subject to examination by major tax jurisdiction:
		Tax Year
	United States	2007-2013
	China	2009-2013
	Algeria	2010-2013
	Ghana	2006-2013

Supplemental_Cash_Flow_Informa1

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Supplemental Cash Flow Table	'
	The following summarizes cash paid (received) for interest (net of amounts capitalized) and income taxes, as well as non-cash investing and financing transactions for the years ended December 31:
	millions	2013		2012			2011
	Cash paid (received)
	Interest	$	627	$	684		$	806
	Income taxes	169		(300		)	262
	Non-cash investing activities
	Fair value of properties and equipment exchanged in non-cash	$	62	$	65		$	19
	transactions
	Gain related to the fair-value remeasurement of Anadarko’s	—		—			21
	pre-acquisition 7% equity interest in the Wattenberg Plant
	Non-cash investing and financing activities
	Capital lease obligation	$	8	$	—		$	(118	)
	Floating production, storage, and offloading vessel construction	17		—			—
	period obligation

Segment_Information_Tables

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Reconciliation of Consolidated Adjusted EBITDAX to Income (Loss) before Income Taxes	'
	Below is a reconciliation of consolidated Adjusted EBITDAX to income (loss) before income taxes for the years ended December 31:
	millions	2013			2012			2011
	Income (loss) before income taxes	$	2,106		$	3,565		$	(3,424	)
	Exploration expense	1,329			1,946			1,076
	DD&A	3,927			3,964			3,830
	Impairments	794			389			1,774
	Interest expense	686			742			839
	Total (gains) losses on derivatives, net, less net cash received in	(307		)	443			675
	settlement of commodity derivatives
	Deepwater Horizon settlement and related costs	15			18			3,930
	Algeria exceptional profits tax settlement	33			(1,797		)	—
	Tronox-related contingent loss	850			(250		)	250
	Certain other nonoperating items	110			—			—
	Less net income attributable to noncontrolling interests	140			54			81
	Consolidated Adjusted EBITDAX	$	9,403		$	8,966		$	8,869
Schedule of Segment Reporting Information, by Segment	'
	The following summarizes selected financial information for Anadarko’s reporting segments:
	millions	Oil and Gas			Midstream			Marketing			Other and			Total
		Exploration									Intersegment
		& Production									Eliminations
	2013
	Sales revenues	$	7,090		$	387		$	7,390		$	—		$	14,867
	Intersegment revenues	6,405			1,105			(6,859		)	(651		)	—
	Gains (losses) on divestitures and other, net	(622		)	(1		)	—			337			(286		)
	Total revenues and other	12,873			1,491			531			(314		)	14,581
	Operating costs and expenses (1)	3,635			843			652			20			5,150
	Net cash received in settlement of	—			—			—			(95		)	(95		)
	commodity derivatives
	Other (income) expense, net (2)	—			—			—			(21		)	(21		)
	Net income attributable to noncontrolling	—			140			—			—			140
	interests
	Total expenses and other	3,635			983			652			(96		)	5,174
	Total (gains) losses on derivatives, net	—			—			(4		)	—			(4		)
	included in marketing revenue, less net
	cash received in settlement
	Adjusted EBITDAX	$	9,238		$	508		$	(125	)	$	(218	)	$	9,403
	Net properties and equipment	$	33,409		$	5,408		$	9		$	2,103		$	40,929
	Capital expenditures	$	7,008		$	1,248		$	—		$	267		$	8,523
	Goodwill	$	5,317		$	175		$	—		$	—		$	5,492
	millions	Oil and Gas			Midstream			Marketing			Other and			Total
		Exploration									Intersegment
		& Production									Eliminations
	2012
	Sales revenues	$	6,752		$	325		$	6,230		$	—		$	13,307
	Intersegment revenues	5,318			959			(5,734		)	(543		)	—
	Gains (losses) on divestitures and other, net	(65		)	(8		)	—			177			104
	Total revenues and other	12,005			1,276			496			(366		)	13,411
	Operating costs and expenses (1)	3,505			748			616			295			5,164
	Net cash received in settlement of	—			—			—			(753		)	(753		)
	commodity derivatives
	Other (income) expense, net (2)	—			—			—			(4		)	(4		)
	Net income attributable to noncontrolling	—			54			—			—			54
	interests
	Total expenses and other	3,505			802			616			(462		)	4,461
	Total (gains) losses on derivatives, net	—			—			16			—			16
	included in marketing revenue, less net
	cash received in settlement
	Adjusted EBITDAX	$	8,500		$	474		$	(104	)	$	96		$	8,966
	Net properties and equipment	$	32,024		$	4,459		$	9		$	1,906		$	38,398
	Capital expenditures	$	5,906		$	1,250		$	—		$	155		$	7,311
	Goodwill	$	5,317		$	175		$	—		$	—		$	5,492
	2011
	Sales revenues	$	7,519		$	342		$	6,023		$	(2	)	$	13,882
	Intersegment revenues	5,005			957			(5,515		)	(447		)	—
	Gains (losses) on divestitures and other, net	(41		)	(13		)	—			139			85
	Total revenues and other	12,483			1,286			508			(310		)	13,967
	Operating costs and expenses (1)	3,696			786			559			186			5,227
	Net cash received in settlement of	—			—			—			(226		)	(226		)
	commodity derivatives
	Other (income) expense, net (2)	—			—			—			4			4
	Net income attributable to noncontrolling	—			81			—			—			81
	interests
	Total expenses and other	3,696			867			559			(36		)	5,086
	Total (gains) losses on derivatives, net	—			—			(12		)	—			(12		)
	included in marketing revenue, less net
	cash received in settlement
	Adjusted EBITDAX	$	8,787		$	419		$	(63	)	$	(274	)	$	8,869
	Net properties and equipment	$	32,235		$	3,432		$	9		$	1,825		$	37,501
	Capital expenditures	$	5,026		$	1,420		$	—		$	107		$	6,553
Goodwill	$	5,475		$	166		$	—		$	—		$	5,641
__________________________________________________________________
-1	Operating costs and expenses exclude 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 Tronox-related contingent loss since this expense is excluded from Adjusted EBITDAX.
Schedule of Sales Revenues by Geographic Areas	'
		Years Ended December 31,
	millions	2013			2012			2011
	Sales Revenues
	United States	$	11,290		$	9,911		$	10,477
	Algeria	2,184			2,182			2,258
	Other International	1,393			1,214			1,147
	Total	$	14,867		$	13,307		$	13,882
Schedule of Net Properties and Equipment by Geographic Areas	'
		December 31,
	millions	2013			2012
	Net Properties and Equipment
	United States	$	35,486		$	33,337
	Algeria	1,582			1,575
	Other International	3,861			3,486
	Total	$	40,929		$	38,398

Pension_Plans_Other_Postretire2

Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans (Tables)	12 Months Ended
	Dec. 31, 2013
Table Text Block [Abstract]	'
Schedule of Changes in Benefit Obligations, Fair Value of Plan Assets, and Funded Status of the Plans	'
	The following sets forth changes in the benefit obligations and fair value of plan assets for the Company’s pension and other postretirement benefit plans for the years ended December 31, 2013 and 2012, as well as the funded status of the plans and amounts recognized in the financial statements at December 31, 2013 and 2012:
		Pension Benefits								Other Benefits
	millions	2013				2012				2013			2012
	Change in benefit obligation
	Benefit obligation at beginning of year	$	2,297			$	2,024			$	359		$	354
	Service cost	85				76				9			9
	Interest cost	78				85				14			16
	Actuarial (gain) loss	(156		)		224				(74		)	(1		)
	Participant contributions	—				1				4			3
	Benefit payments	(149		)		(117		)		(18		)	(22		)
	Foreign-currency exchange-rate changes	3				4				—			—
	Benefit obligation at end of year (1)	$	2,158			$	2,297			$	294		$	359
	Change in plan assets
	Fair value of plan assets at beginning of year	$	1,462			$	1,308			$	—		$	—
	Actual return on plan assets	278				159				—			—
	Employer contributions	160				107				14			19
	Participant contributions	—				1				4			3
	Benefit payments	(149		)		(117		)		(18		)	(22		)
	Foreign-currency exchange-rate changes	3				4				—			—
	Fair value of plan assets at end of year	$	1,754			$	1,462			$	—		$	—
	Funded status of the plans at end of year	$	(404	)		$	(835	)		$	(294	)	$	(359	)
	__________________________________________________________________
	-1	The accumulated benefit obligation for all defined-benefit pension plans was $1.8 billion at December 31, 2013, and $2.1 billion at December 31, 2012.
Schedule of Amounts Recognized in Balance Sheet	'
	Total recognized amounts in the balance sheet consist of
	Other assets	$	37			$	30			$	—		$	—
	Accrued expenses	(19		)		(44		)		(15		)	(16		)
	Other long-term liabilities—other	(422		)		(821		)		(279		)	(343		)
	Total	$	(404	)		$	(835	)		$	(294	)	$	(359	)
Schedule of Total Recognized Amounts in Accumulated Other Comprehensive Income	'
	Total recognized amounts in accumulated other
	comprehensive income consist of
	Prior service cost (credit)	$	(1	)		$	(2	)		$	2		$	3
	Net actuarial (gain) loss	441				916				(78		)	(4		)
	Total	$	440			$	914			$	(76	)	$	(1	)
Schedule of Defined-Benefit Pension Plans With Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets	'
	The following summarizes the Company’s defined-benefit pension plans with accumulated benefit obligations in excess of plan assets for the years ended December 31:
	millions	2013				2012
	Projected benefit obligation	$	2,047			$	2,198
	Accumulated benefit obligation	1,742				2,054
	Fair value of plan assets	1,606				1,333
Components of Net Periodic Benefit Cost Table	'
	The following summarizes the Company’s pension and other postretirement benefit cost and amounts recognized in other comprehensive income (before tax benefit) for the years ended December 31:
		Pension Benefits											Other Benefits
	millions	2013				2012				2011			2013				2012		2011
	Components of net periodic benefit cost
	Service cost	$	85			$	76			$	78		$	9			$	9	$	9
	Interest cost	78				85				85			14				16		16
	Expected return on plan assets	(91		)		(91		)		(85		)	—				—		—
	Amortization of net actuarial loss (gain)	118				93				85			—				—		—
	Amortization of net prior service cost (credit)	—				—				2			1				2		—
	Settlement loss	14				—				—			—				—		—
	Net periodic benefit cost	$	204			$	163			$	165		$	24			$	27	$	25
Schedule of Amounts Recognized in Other Comprehensive Income	'
	Amounts recognized in other comprehensive
	income (expense)
	Net actuarial gain (loss)	$	342			$	(156	)		$	(183	)	$	74			$	1	$	(30	)
	Amortization of net actuarial (gain) loss	118				93				85			—				—		—
	Net prior service (cost) credit	—				—				12			—				—		—
	Amortization of net prior service cost (credit)	—				—				2			1				2		—
	Settlement loss	14				—				—			—				—		—
	Total amounts recognized in other	$	474			$	(63	)		$	(84	)	$	75			$	3	$	(30	)
	comprehensive income (expense)
Schedule of Assumptions Used	'
	The following summarizes the weighted-average assumptions used by the Company in determining the pension and other postretirement benefit obligations at December 31:
		Pension Benefits						Other Benefits
		2013			2012			2013			2012
	Discount rate	4.75	%		3.5	%		5.25	%		4	%
	Rates of increase in compensation levels	5	%		4.5	%		5.25	%		4.5	%
	The following summarizes the weighted-average assumptions used by the Company in determining the net periodic pension and other postretirement benefit cost:
		Pension Benefits									Other Benefits
		2013			2012			2011			2013		2012			2011
	Discount rate	3.5	%		4.5	%		4.75	%		4	%	4.75	%		5.25	%
	Long-term rate of return on plan assets	7	%		7	%		7	%		N/A		N/A			N/A
	Rates of increase in compensation levels	4.5	%		4.5	%		5	%		4.5	%	4.5	%		5	%
Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates	'
	A 1% change in the assumed health care cost trend rate over the projected period would have the following effects:
	millions	1% Increase				1% Decrease
	Effect on total of service and interest cost components	$	3			$	(2	)
	Effect on other postretirement benefit obligation	$	23			$	(20	)
Fair Value Hierarchy of Plan Assets Table	'
	The fair value of the Company’s pension plan assets by asset class and input level within the fair-value hierarchy were as follows:
	millions
	December 31, 2013	Level 1				Level 2				Level 3			Total
	Investments
	Cash and cash equivalents	$	17			$	80			$	—		$	97
	Fixed income
	Mortgage-backed securities	—				54				—			54
	U.S. government securities	—				52				—			52
	Other fixed-income securities (1)	42				197				—			239
	Equity securities
	Domestic	445				116				—			561
	International	148				303				—			451
	Other
	Real estate	—				47				86			133
	Private equity	—				—				72			72
	Hedge funds and other alternative strategies	31				—				79			110
	Total investments (2)	$	683			$	849			$	237		$	1,769
	Liabilities
	Hedge funds and other alternative strategies	$	(17	)		$	—			$	—		$	(17	)
	Total liabilities	$	(17	)		$	—			$	—		$	(17	)
	December 31, 2012
	Investments
	Cash and cash equivalents	$	23			$	36			$	—		$	59
	Fixed income
	Mortgage-backed securities	—				63				—			63
	U.S. government securities	—				54				—			54
	Other fixed-income securities (1)	40				196				—			236
	Equity securities
	Domestic	313				109				—			422
	International	112				238				—			350
	Other
	Real estate	—				46				78			124
	Private equity	—				—				64			64
	Hedge funds and other alternative strategies	20				—				77			97
	Total investments (2)	$	508			$	742			$	219		$	1,469
	Liabilities
	Hedge funds and other alternative strategies	$	(11	)		$	—			$	—		$	(11	)
	Total liabilities	$	(11	)		$	—			$	—		$	(11	)
	__________________________________________________________________
	(1)	Amounts include investments in diversified fixed-income collective investment funds with exposure to mortgage-backed securities, government-issued securities, corporate debt, and other fixed-income securities.
	(2)	Amount excludes net receivables of $2 million for 2013 and $4 million for 2012, primarily related to Level 1 investments.
Schedule of Changes in Level 3 Fair Value of Investments	'
	The following summarizes changes in the fair value of investments based on Level 3 inputs:
	millions	Hedge Funds				Private				Real Estate			Total
		and Other				Equity
		Alternative
		Strategies
	Balance at January 1, 2012	$	64			$	55			$	72		$	191
	Acquisitions (dispositions), net	9				4				2			15
	Actual return on plan assets
	Relating to assets sold during the reporting period	(2		)		2				—			—
	Relating to assets still held at the reporting date	6				3				4			13
	Balance at December 31, 2012	$	77			$	64			$	78		$	219
	Acquisitions (dispositions), net	(6		)		—				2			(4		)
	Actual return on plan assets
	Relating to assets sold during the reporting period	1				4				—			5
	Relating to assets still held at the reporting date	7				4				6			17
	Balance at December 31, 2013	$	79			$	72			$	86		$	237
Schedule of Expected Future Benefit Payments	'
	The following summarizes estimated benefit payments for the next ten years, including benefit increases due to continuing employee service:
	millions	Pension				Other
		Benefit				Benefit
		Payments				Payments
	2014	$	139			$	15
	2015	148				16
	2016	163				16
	2017	185				17
	2018	181				18
	2019-2023	1,065				98

Summary_of_Significant_Account2

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013
In Millions, unless otherwise specified			Furniture And Equipment [Member]	Furniture And Equipment [Member]	Buildings [Member]	Gathering Facilities [Member]
			Minimum [Member]	Maximum [Member]	Maximum [Member]	Maximum [Member]
Property, Plant, and Equipment [Line Items]	'	'	'	'	'	'
Useful life of assets	'	'	'3 years	'15 years	'40 years	'47 years
Outstanding checks in excess of bank account balances	$326	$339	'	'	'	'

Acquisitions_Divestitures_and_2

Acquisitions, Divestitures, and Assets Held for Sale - Acquisitions Table (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Business Acquisition [Line Items]	'		'	'
Purchase price	$473		$0	$802
Moxa Oil and Gas Properties [Member]	'		'	'
Business Acquisition [Line Items]	'		'	'
Ownership interest purchased	100.00%		'	'
Purchase price	310	[1]	'	'
Fair value, oil and gas properties acquired	306		'	'
Marcellus Interest in Gas Gathering Systems [Member]	'		'	'
Business Acquisition [Line Items]	'		'	'
Ownership interest purchased	33.75%		'	'
Purchase price	135		'	'
Mont Belvieu Joint Venture [Member]	'		'	'
Business Acquisition [Line Items]	'		'	'
Ownership interest purchased	25.00%		'	'
Purchase price	78		'	'
Intrastate Pipeline in Wyoming [Member]	'		'	'
Business Acquisition [Line Items]	'		'	'
Ownership interest purchased	100.00%		'	'
Purchase price	28		'	'
Natural-Gas Processing Plant and Related Gathering Systems [Member]	'		'	'
Business Acquisition [Line Items]	'		'	'
Ownership interest purchased	'		'	100.00%
Purchase price	'		'	302
Wattenberg Natural Gas Processing Plant [Member]	'		'	'
Business Acquisition [Line Items]	'		'	'
Ownership interest purchased	'		'	93.00%
Purchase price	'		'	500	[2]
Loss on Anadarko's preexisting contracts with the previous Wattenberg Plant owner	'		'	$76
Ownership interest	'		'	100.00%
[1]	Includes $306 million that represents the fair value of the oil and gas properties acquired.
[2]	The Company recognized a $76 million loss on preexisting contracts with the previous Wattenberg Plant owner in addition to the cash paid in the Wattenberg Plant acquisition. Anadarko operates and owns a 100% interest in the Wattenberg Plant.

Acquisitions_Divestitures_and_3

Acquisitions, Divestitures, and Assets Held for Sale - Divestitures (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property, Plant, and Equipment [Line Items]	'	'	'
Proceeds from divestitures	$567	$657	$555
Net gains (losses) on divestitures	-470	-71	22
Assets Held For Use [Member]	'	'	'
Property, Plant, and Equipment [Line Items]	'	'	'
Proceeds from divestitures	509	433	'
Net gains (losses) on divestitures	234	-43	'
Assets Held For Use [Member] | Peregrino Field [Member]	'	'	'
Property, Plant, and Equipment [Line Items]	'	'	'
Proceeds from divestitures	'	'	$419

Acquisitions_Divestitures_and_4

Acquisitions, Divestitures, and Assets Held for Sale - Property Exchange (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Nonmonetary Transaction [Line Items]	'	'	'
Cash paid in property exchange	$7,721,000,000	$7,242,000,000	$5,650,000,000
Wattenberg Property [Member]	'	'	'
Nonmonetary Transaction [Line Items]	'	'	'
Gain or loss recognized in property exchange	0	'	'
Cash paid in property exchange	$106,000,000	'	'

Acquisitions_Divestitures_and_5

Acquisitions, Divestitures, and Assets Held for Sale - Assets Held for Sale (Details) (Assets Held For Sale [Member], USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2012	Dec. 31, 2013
In Millions, unless otherwise specified			Oil and Gas Exploration and Production Reporting Segment [Member]	Oil and Gas Exploration and Production Reporting Segment [Member]
				Fair Value, Inputs, Level 2 [Member]
				Market Approach Valuation Technique [Member]
				Nonrecurring [Member]
Long Lived Assets Held-for-sale [Line Items]	'	'	'	'
Losses on assets held for sale	'	'	'	$704
Long-term assets associated with assets held-for-sale	616	'	'	'
Long-term liabilities associated with assets held for sale	27	'	'	'
Losses on assets held for sale	'	'	$28	'

Acquisitions_Divestitures_and_6

Acquisitions, Divestitures, and Assets Held for Sale - Subsequent Events (Details) (USD $)	12 Months Ended			1 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Feb. 28, 2014	Feb. 28, 2014	Jan. 31, 2014
				Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]
				Rovuma Offshore Area 1 in Mozambique [Member]	China Oil and Gas Properties [Member]	Pinedale/Jonah Assets [Member]
Subsequent Event [Line Items]	'	'	'	'	'	'
Working interest sold	'	'	'	10.00%	'	'
Proceeds from divestitures	$567	$657	$555	$2,640	'	$581
Expected proceeds from divestiture	'	'	'	'	$1,075	'

Inventories_Detail

Inventories (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Energy Related Inventory [Abstract]	'	'
Crude oil	$88	$91
Natural gas	43	48
NGLs	79	37
Total	$210	$176

Properties_and_Equipment_Detai

Properties and Equipment (Detail) (USD $)	Dec. 31, 2013		Dec. 31, 2012
Property, Plant, and Equipment [Line Items]	'		'
Cost of properties and equipment	$71,244,000,000		$63,598,000,000
Oil and Gas Exploration and Production Reporting Segment [Member]	'		'
Property, Plant, and Equipment [Line Items]	'		'
Cost of properties and equipment	61,302,000,000	[1]	55,180,000,000	[1]
Table Text Block Supplement [Abstract]	'		'
Costs associated with unproved properties	6,900,000,000		7,100,000,000
Midstream Reporting Segment [Member]	'		'
Property, Plant, and Equipment [Line Items]	'		'
Cost of properties and equipment	7,285,000,000		6,032,000,000
Marketing Reporting Segment [Member]	'		'
Property, Plant, and Equipment [Line Items]	'		'
Cost of properties and equipment	9,000,000		9,000,000
Other and Intersegment Eliminations [Member]	'		'
Property, Plant, and Equipment [Line Items]	'		'
Cost of properties and equipment	$2,648,000,000		$2,377,000,000
[1]	Includes costs associated with unproved properties of $6.9 billion at December 31, 2013, and $7.1 billion at December 31, 2012.

Impairments_Impairments_by_Seg

Impairments - Impairments by Segment Table (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Impaired Long Lived Assets Held and Used [Line Items]	'	'	'
Impairments	$794	$389	$1,774
Oil and Gas Exploration and Production Reporting Segment [Member]	'	'	'
Impaired Long Lived Assets Held and Used [Line Items]	'	'	'
Cost-method investment	11	13	91
Oil and Gas Exploration and Production Reporting Segment [Member] | U.S. Onshore Properties [Member]	'	'	'
Impaired Long Lived Assets Held and Used [Line Items]	'	'	'
Long-lived assets held for use	142	259	1,063
Oil and Gas Exploration and Production Reporting Segment [Member] | Gulf of Mexico Properties [Member]	'	'	'
Impaired Long Lived Assets Held and Used [Line Items]	'	'	'
Long-lived assets held for use	562	104	162
Midstream Reporting Segment [Member]	'	'	'
Impaired Long Lived Assets Held and Used [Line Items]	'	'	'
Long-lived assets held for use	$79	$13	$458

Impairments_Fair_Value_Measure

Impairments - Fair Value Measurements Table (Detail) (Fair Value, Inputs, Level 3 [Member], Income Approach Valuation Technique [Member], Nonrecurring [Member], USD $)	Dec. 31, 2013		Dec. 31, 2012
In Millions, unless otherwise specified
Fair Value, Inputs, Level 3 [Member] | Income Approach Valuation Technique [Member] | Nonrecurring [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Long-lived assets held for use	$548		$103
Cost-method investment (1)	$32	[1]	$34	[1]
[1]	This represents the Company’s after-tax net investment.

Impairments_Impairments_of_Unp

Impairments - Impairments of Unproved Properties (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property, Plant, and Equipment [Line Items]	'	'	'
Impairment of unproved properties	$864	$1,544	$625
U.S. Onshore Properties [Member]	'	'	'
Property, Plant, and Equipment [Line Items]	'	'	'
Impairment of unproved properties	'	721	'
Gulf of Mexico Properties [Member]	'	'	'
Property, Plant, and Equipment [Line Items]	'	'	'
Impairment of unproved properties	'	$124	'

Suspended_Exploratory_Well_Cos2

Suspended Exploratory Well Costs - Rollforward (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Increase (Decrease) in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward]	'	'	'
Balance at January 1	$2,062	$1,353	$935
Additions pending the determination of proved reserves	848	960	572
Divestitures	-48	0	0
Reclassifications to proved properties	-507	-129	-116
Charges to exploration expense	-123	-122	-38
Balance at December 31	$2,232	$2,062	$1,353

Suspended_Exploratory_Well_Cos3

Suspended Exploratory Well Costs - Aging by Geographic Area and the Year the Costs Were Suspended (Detail) (USD $)

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

In Millions, unless otherwise specified

Project

Aging of Capitalized Exploratory Well Costs, Period One [Member]

Aging of Capitalized Exploratory Well Costs, Period Two [Member]

Aging of Capitalized Exploratory Well Costs, Period Three [Member]

United States Onshore [Member]

United States Onshore [Member]

United States Onshore [Member]

United States Onshore [Member]

United States Offshore [Member]

United States Offshore [Member]

United States Offshore [Member]

United States Offshore [Member]

International [Member]

International [Member]

International [Member]

International [Member]

Aging of Capitalized Exploratory Well Costs, Period One [Member]

Aging of Capitalized Exploratory Well Costs, Period Two [Member]

Aging of Capitalized Exploratory Well Costs, Period Three [Member]

Aging of Capitalized Exploratory Well Costs, Period One [Member]

Aging of Capitalized Exploratory Well Costs, Period Two [Member]

Aging of Capitalized Exploratory Well Costs, Period Three [Member]

Aging of Capitalized Exploratory Well Costs, Period One [Member]

Aging of Capitalized Exploratory Well Costs, Period Two [Member]

Aging of Capitalized Exploratory Well Costs, Period Three [Member]

Capitalized Exploratory Well Costs [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Suspended exploratory well costs

$2,232

$2,062

$1,353

$935

'

'

'

$160

'

'

'

$461

'

'

'

$1,611

'

'

'

Suspended exploratory well costs capitalized for a period less than one year after completion of drilling

711

[1]

'

'

'

'

'

'

143

[1]

'

'

'

126

[1]

'

'

'

442

[1]

'

'

'

Suspended exploratory well costs capitalized for a period greater than one year after completion of drilling

'

'

'

'

$669

$328

$524

'

$6

$1

$10

'

$137

$24

$174

'

$526

$303

$340

Aging of Capitalized Exploratory Well Costs, Period Start Date

'

'

'

'

1-Jan-12

1-Jan-11

'

'

'

'

'

'

'

'

'

'

'

'

'

Aging of Capitalized Exploratory Well Costs, Period End Date

'

'

'

'

31-Dec-12

31-Dec-11

31-Dec-10

'

'

'

'

'

'

'

'

'

'

'

'

Projects with exploratory well costs capitalized for a period greater than one year after completion of drilling

14

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

[1]

Excludes additions subsequently reclassified to proved properties within the same year.

Asset_Retirement_Obligations_D

Asset Retirement Obligations (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]	'	'
Carrying amount of asset retirement obligations at January 1	$1,885	$1,768
Liabilities incurred	182	70
Property dispositions	-76	-78
Liabilities settled	-162	-89
Accretion expense	110	110
Revisions in estimated liabilities	83	104
Carrying amount of asset retirement obligations at December 31	$2,022	$1,885

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible Assets - Goodwill (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill and Intangible Assets Disclosure [Abstract]	'	'	'
Goodwill impairment loss	$0	'	'
Goodwill [Line Items]	'	'	'
Goodwill	5,492,000,000	5,492,000,000	5,641,000,000
Oil and Gas Exploration and Production Reporting Unit [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Goodwill	5,300,000,000	'	'
Other Gathering and Processing Reporting Unit [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Goodwill	70,000,000	'	'
WES Gathering and Processing Reporting Unit [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Goodwill	100,000,000	'	'
Transportation Reporting Unit [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Goodwill	$5,000,000	'	'

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible Assets - Other Intangible Assets Amortization Expense Table (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Finite Lived Intangible Assets [Line Items]	'	'
Gross carrying amount	$229	$229
Accumulated amortization	-59	-41
Net carrying amount	170	188
Amortization expense	7	6
Offshore Platform Leases [Member]	'	'
Finite Lived Intangible Assets [Line Items]	'	'
Gross carrying amount	60	60
Accumulated amortization	-50	-36
Net carrying amount	10	24
Amortization expense	3	3
Customer Contracts [Member]	'	'
Finite Lived Intangible Assets [Line Items]	'	'
Gross carrying amount	169	169
Accumulated amortization	-9	-5
Net carrying amount	160	164
Amortization expense	$4	$3

Goodwill_and_Other_Intangible_4

Goodwill and Other Intangible Assets - Other Intangible Assets (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013
Finite Lived Intangible Assets [Line Items]	'
Estimated aggregate amortization expense for intangible assets in 2014	'
Estimated aggregate amortization expense for intangible assets in 2015	'
Estimated aggregate amortization expense for intangible assets in 2016	'
Estimated aggregate amortization expense for intangible assets in 2017	'
Estimated aggregate amortization expense for intangible assets in 2018	'
Customer Contracts [Member]	'
Finite Lived Intangible Assets [Line Items]	'
Acquired intangible assets, useful life	'50 years

Noncontrolling_Interests_Detai

Noncontrolling Interests (Detail) (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Noncontrolling Interest [Line Items]	'	'	'
Net proceeds raised from offering by subsidiary	$724	$623	$328
Western Gas Equity Partners, LP [Member]	'	'	'
Noncontrolling Interest [Line Items]	'	'	'
Net proceeds raised from initial public offering by subsidiary	'	411	'
Western Gas Equity Partners, LP [Member] | IPO [Member]	'	'	'
Noncontrolling Interest [Line Items]	'	'	'
Common units issued to the public	'	20	'
Issuance price per common unit	'	$22	'
Western Gas Equity Partners, LP [Member] | Limited Partner [Member]	'	'	'
Noncontrolling Interest [Line Items]	'	'	'
Ownership interest in subsidiary	91.00%	'	'
Public ownership interest in subsidiary	9.00%	'	'
Western Gas Partners, LP [Member]	'	'	'
Noncontrolling Interest [Line Items]	'	'	'
Common units issued to the public	12	5	10
Net proceeds raised from offering by subsidiary	$725	$212	$328
Western Gas Partners, LP [Member] | Limited Partner [Member]	'	'	'
Noncontrolling Interest [Line Items]	'	'	'
Public ownership interest in subsidiary	56.40%	'	'
Western Gas Partners, LP [Member] | Limited Partner [Member] | Western Gas Equity Partners, LP, Ownership Interest [Member]	'	'	'
Noncontrolling Interest [Line Items]	'	'	'
Ownership interest in subsidiary	41.20%	'	'
Western Gas Partners, LP [Member] | Limited Partner [Member] | Other Anadarko Subsidiary, Ownership Interest [Member]	'	'	'
Noncontrolling Interest [Line Items]	'	'	'
Ownership interest in subsidiary	0.40%	'	'
Western Gas Partners, LP [Member] | General Partner [Member] | Western Gas Equity Partners, LP, Ownership Interest [Member]	'	'	'
Noncontrolling Interest [Line Items]	'	'	'
Ownership interest in subsidiary	2.00%	'	'

EquityMethod_Investments_Detai

Equity-Method Investments (Detail) (Equity Method Investments [Member], USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2007
Schedule of Equity Method Investments [Line Items]	'	'	'	'
Fair value of oil and gas properties and gathering and processing assets contributed by Anadarko	'	'	'	$2,900,000,000
Ownership interest of investee entities	95.00%	'	'	'
Carrying amount of notes payable to affiliates	2,900,000,000	'	'	2,900,000,000
Carrying amount of investments	2,800,000,000	'	'	'
Applicable interest rate	1.24%	1.31%	'	'
Interest expense on the notes payable	37,000,000	42,000,000	38,000,000	'
Equity earnings from Anadarko's investments in the investee entities	($42,000,000)	($43,000,000)	($41,000,000)	'
Maximum [Member]	'	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'	'
Debt-to-capital ratio covenant	0.67	'	'	'

Derivative_Instruments_Oil_and

Derivative Instruments - Oil and Natural-Gas Production/Processing Derivative Activities Table (Detail) (Not Designated as Hedging Instrument [Member], Price Risk Derivative [Member])	12 Months Ended
	Dec. 31, 2013
Three-Way Collars Natural Gas 2014 [Member]	'
Derivative [Line Items]	'
Derivative nonmonetary notional amount per day	600,000
Three Way Collars Natural Gas 2015 [Member]	'
Derivative [Line Items]	'
Derivative nonmonetary notional amount per day	635,000
Fixed-Price Contracts Natural Gas 2014 [Member]	'
Derivative [Line Items]	'
Derivative nonmonetary notional amount per day	600,000
Average price per MMBtu or barrel	'
Average price per MMBtu or barrel	4.26
Extendable Fixed-Price Contracts Natural Gas January 2014 to June 2014 [Member]	'
Derivative [Line Items]	'
Derivative nonmonetary notional amount per day	400,000	[1]
Average price per MMBtu or barrel	'
Average price per MMBtu or barrel	4.19
Fixed-Price Contracts Crude Oil 2014 [Member]	'
Derivative [Line Items]	'
Derivative nonmonetary notional amount per day	107
Average price per MMBtu or barrel	'
Average price per MMBtu or barrel	100.58
Call Option [Member] | Short [Member] | Three-Way Collars Natural Gas 2014 [Member]	'
Average price per MMBtu or barrel	'
Average ceiling price	5.01
Call Option [Member] | Short [Member] | Three Way Collars Natural Gas 2015 [Member]	'
Average price per MMBtu or barrel	'
Average ceiling price	4.76
Put Option [Member] | Short [Member] | Three-Way Collars Natural Gas 2014 [Member]	'
Average price per MMBtu or barrel	'
Average floor price	2.75
Put Option [Member] | Short [Member] | Three Way Collars Natural Gas 2015 [Member]	'
Average price per MMBtu or barrel	'
Average floor price	2.75
Put Option [Member] | Long [Member] | Three-Way Collars Natural Gas 2014 [Member]	'
Average price per MMBtu or barrel	'
Average floor price	3.75
Put Option [Member] | Long [Member] | Three Way Collars Natural Gas 2015 [Member]	'
Average price per MMBtu or barrel	'
Average floor price	3.75
[1]	The extendable fixed-price contracts have a contract term of January 2014 to June 2014 with an option to extend the contract term to December 2014 at the same price.

Derivative_Instruments_Additio

Derivative Instruments - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Derivative [Line Items]	'	'	'
Cash received (paid) in settlement of derivative instruments	$85,000,000	$685,000,000	$147,000,000
Revolving Credit Facility [Member]	'	'	'
Derivative [Line Items]	'	'	'
Five billion dollar facility	5,000,000,000	'	'
Securing most derivative counterparties [Member] | Revolving Credit Facility [Member]	'	'	'
Derivative [Line Items]	'	'	'
Five billion dollar facility	5,000,000,000	'	'
Not Designated as Hedging Instrument [Member]	'	'	'
Derivative [Line Items]	'	'	'
Gross derivative liability	986,000,000	1,419,000,000	'
Aggregate fair value of derivative instruments with credit-risk-related contingent features for which a net liability position existed, net of collateral	42,000,000	94,000,000	'
Not Designated as Hedging Instrument [Member] | Permitted to Offset Gross Derivative Asset with Financial Institutions [Member]	'	'	'
Derivative [Line Items]	'	'	'
Gross derivative liability	76,000,000	339,000,000	'
Not Designated as Hedging Instrument [Member] | Interest Rate Swap 3 and 4 [Member]	'	'	'
Derivative [Line Items]	'	'	'
Swap maturity date	'	1-Oct-12	'
Aggregate notional principal amount of interest-rate swap	'	800,000,000	'
Not Designated as Hedging Instrument [Member] | Interest Rate Swap 1 and 2 [Member]	'	'	'
Derivative [Line Items]	'	'	'
Swap maturity date	'	'	1-Oct-11
Aggregate notional principal amount of interest-rate swap	'	'	1,850,000,000
Not Designated as Hedging Instrument [Member] | Interest-Rate Swap Agreement [Member]	'	'	'
Derivative [Line Items]	'	'	'
Aggregate notional principal amount of interest-rate swap	'	200,000,000	150,000,000
Cash received (paid) in settlement of derivative instruments	'	-64,000,000	-57,000,000
Gross derivative liability	$654,000,000	$1,194,000,000	'
Not Designated as Hedging Instrument [Member] | Commodity [Member] | Natural Gas [Member]	'	'	'
Derivative [Line Items]	'	'	'
Financial derivative transactions	16,000,000	22,000,000	'

Derivative_Instruments_Interes

Derivative Instruments - Interest-Rate Derivatives Table (Detail) (Not Designated as Hedging Instrument [Member], USD $)	12 Months Ended
	Dec. 31, 2013
Interest-Rate Swap 1 [Member]	'
Derivative [Line Items]	'
Notional principal amount of interest-rate swap	750,000,000
Weighted-average interest rate for interest-rate swap	6.00%
Interest-Rate Swap 1 [Member] | Minimum [Member]	'
Derivative [Line Items]	'
Reference period for interest-rate swap	1-Jun-14
Interest-Rate Swap 1 [Member] | Maximum [Member]	'
Derivative [Line Items]	'
Reference period for interest-rate swap	1-Jun-24
Interest-Rate Swap 2 [Member]	'
Derivative [Line Items]	'
Notional principal amount of interest-rate swap	1,100,000,000
Weighted-average interest rate for interest-rate swap	5.57%
Interest-Rate Swap 2 [Member] | Minimum [Member]	'
Derivative [Line Items]	'
Reference period for interest-rate swap	1-Jun-14
Interest-Rate Swap 2 [Member] | Maximum [Member]	'
Derivative [Line Items]	'
Reference period for interest-rate swap	1-Jun-44
Interest-Rate Swap 3 [Member]	'
Derivative [Line Items]	'
Notional principal amount of interest-rate swap	50,000,000
Weighted-average interest rate for interest-rate swap	5.91%
Interest-Rate Swap 3 [Member] | Minimum [Member]	'
Derivative [Line Items]	'
Reference period for interest-rate swap	1-Sep-16
Interest-Rate Swap 3 [Member] | Maximum [Member]	'
Derivative [Line Items]	'
Reference period for interest-rate swap	1-Sep-26
Interest-Rate Swap 4 [Member]	'
Derivative [Line Items]	'
Notional principal amount of interest-rate swap	750,000,000
Weighted-average interest rate for interest-rate swap	5.86%
Interest-Rate Swap 4 [Member] | Minimum [Member]	'
Derivative [Line Items]	'
Reference period for interest-rate swap	1-Sep-16
Interest-Rate Swap 4 [Member] | Maximum [Member]	'
Derivative [Line Items]	'
Reference period for interest-rate swap	1-Sep-46

Derivative_Instruments_Effect_

Derivative Instruments - Effect of Derivative Instruments - Balance Sheet Table (Detail) (Not Designated as Hedging Instrument [Member], USD $)	Dec. 31, 2013		Dec. 31, 2012
In Millions, unless otherwise specified
Derivatives Fair Value [Line Items]	'		'
Gross derivative assets	$380		$506
Gross derivative liabilities	-986		-1,419
Commodity Derivatives [Member]	'		'
Derivatives Fair Value [Line Items]	'		'
Gross derivative assets	380		506
Gross derivative liabilities	-332		-225
Commodity Derivatives [Member] | Other Current Assets [Member]	'		'
Derivatives Fair Value [Line Items]	'		'
Gross derivative assets	181		475
Gross derivative liabilities	-102		-197
Commodity Derivatives [Member] | Other Assets [Member]	'		'
Derivatives Fair Value [Line Items]	'		'
Gross derivative assets	89		24
Gross derivative liabilities	-66		-7
Commodity Derivatives [Member] | Accrued Expenses [Member]	'		'
Derivatives Fair Value [Line Items]	'		'
Gross derivative assets	106		6
Gross derivative liabilities	-149		-14
Commodity Derivatives [Member] | Other Liabilities [Member]	'		'
Derivatives Fair Value [Line Items]	'		'
Gross derivative assets	4		1
Gross derivative liabilities	-15		-7
Interest-Rate and Other Derivatives [Member]	'		'
Derivatives Fair Value [Line Items]	'		'
Gross derivative assets	0		0
Gross derivative liabilities	-654		-1,194
Interest-Rate and Other Derivatives [Member] | Accrued Expenses [Member]	'		'
Derivatives Fair Value [Line Items]	'		'
Gross derivative assets	0		0
Gross derivative liabilities	-480	[1]	0
Interest-Rate and Other Derivatives [Member] | Other Liabilities [Member]	'		'
Derivatives Fair Value [Line Items]	'		'
Gross derivative assets	0		0
Gross derivative liabilities	($174)	[1]	($1,194)	[1]
[1]	Interest-rate swaps with June 2014 maturity dates were reclassified from other liabilities to accrued expenses during 2013.

Derivative_Instruments_Effect_1

Derivative Instruments - Effect of Derivative Instruments - Statement of Income Table (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Derivative [Line Items]	'		'		'
Total (gains) losses on derivatives, net	($392)		($308)		$469
Gathering, Processing, and Marketing Sales and Gains (Losses) on Derivatives, Net [Member]	'		'		'
Derivative [Line Items]	'		'		'
Total (gains) losses on derivatives, net	-392		-308		469
Commodity Derivatives [Member] | Gathering, Processing, and Marketing Sales [Member]	'		'		'
Derivative [Line Items]	'		'		'
Total (gains) losses on derivatives, net	6	[1]	18	[1]	8	[1]
Commodity Derivatives [Member] | (Gains) Losses on Derivatives, net [Member]	'		'		'
Derivative [Line Items]	'		'		'
Total (gains) losses on derivatives, net	141		-387		-562
Interest-Rate and Other Derivatives [Member] | (Gains) Losses on Derivatives, net [Member]	'		'		'
Derivative [Line Items]	'		'		'
Total (gains) losses on derivatives, net	($539)		$61		$1,023
[1]	Represents the effect of marketing and trading derivative activities.

Derivative_Instruments_Fair_Va

Derivative Instruments - Fair Value Table (Detail) (Not Designated as Hedging Instrument [Member], USD $)	Dec. 31, 2013		Dec. 31, 2012
In Millions, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Gross derivative assets	$380		$506
Gross derivative liabilities	-986		-1,419
Derivative assets netting	-279	[1]	-211	[1]
Derivative liabilities netting	279	[1]	211	[1]
Cash collateral from counterparties	0		0
Cash collateral held by counterparties	7		1
Derivative assets	101		295
Derivative liabilities	-700		-1,207
Commodity Derivatives [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Gross derivative assets	380		506
Gross derivative liabilities	-332		-225
Interest-Rate and Other Derivatives [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Gross derivative assets	0		0
Gross derivative liabilities	-654		-1,194
Derivative liabilities netting	0	[1]	0	[1]
Cash collateral held by counterparties	0		0
Derivative liabilities	-654		-1,194
Financial Institutions [Member] | Commodity Derivatives [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Derivative assets netting	-153	[1]	-206	[1]
Derivative liabilities netting	153	[1]	206	[1]
Cash collateral from counterparties	0		0
Cash collateral held by counterparties	7		1
Derivative assets	58		253
Derivative liabilities	-40		-1
Other Counterparties [Member] | Commodity Derivatives [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Derivative assets netting	-126	[1]	-5	[1]
Derivative liabilities netting	126	[1]	5	[1]
Cash collateral from counterparties	0		0
Cash collateral held by counterparties	0		0
Derivative assets	43		42
Derivative liabilities	-6		-12
Fair Value, Inputs, Level 1 [Member] | Recurring [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Gross derivative assets	0		6
Gross derivative liabilities	0		-6
Fair Value, Inputs, Level 1 [Member] | Interest-Rate and Other Derivatives [Member] | Recurring [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Gross derivative liabilities	0		0
Fair Value, Inputs, Level 1 [Member] | Financial Institutions [Member] | Commodity Derivatives [Member] | Recurring [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Gross derivative assets	0		6
Gross derivative liabilities	0		-6
Fair Value, Inputs, Level 1 [Member] | Other Counterparties [Member] | Commodity Derivatives [Member] | Recurring [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Gross derivative assets	0		0
Gross derivative liabilities	0		0
Fair Value, Inputs, Level 2 [Member] | Recurring [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Gross derivative assets	380		500
Gross derivative liabilities	-986		-1,413
Fair Value, Inputs, Level 2 [Member] | Interest-Rate and Other Derivatives [Member] | Recurring [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Gross derivative liabilities	-654		-1,194
Fair Value, Inputs, Level 2 [Member] | Financial Institutions [Member] | Commodity Derivatives [Member] | Recurring [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Gross derivative assets	211		453
Gross derivative liabilities	-200		-202
Fair Value, Inputs, Level 2 [Member] | Other Counterparties [Member] | Commodity Derivatives [Member] | Recurring [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Gross derivative assets	169		47
Gross derivative liabilities	-132		-17
Fair Value, Inputs, Level 3 [Member] | Recurring [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Gross derivative assets	0		0
Gross derivative liabilities	0		0
Fair Value, Inputs, Level 3 [Member] | Interest-Rate and Other Derivatives [Member] | Recurring [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Gross derivative liabilities	0		0
Fair Value, Inputs, Level 3 [Member] | Financial Institutions [Member] | Commodity Derivatives [Member] | Recurring [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Gross derivative assets	0		0
Gross derivative liabilities	0		0
Fair Value, Inputs, Level 3 [Member] | Other Counterparties [Member] | Commodity Derivatives [Member] | Recurring [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Gross derivative assets	0		0
Gross derivative liabilities	$0		$0
[1]	Represents the impact of netting commodity derivative assets and liabilities with counterparties where the Company has the contractual right and intends to net settle.

Debt_and_Interest_Expense_Outs

Debt and Interest Expense - Outstanding Debt Table (Detail) (USD $)

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

In Millions, unless otherwise specified

5.750% Senior Notes due 2014

5.750% Senior Notes due 2014

7.625% Senior Notes due 2014

7.625% Senior Notes due 2014

5.950% Senior Notes due 2016

5.950% Senior Notes due 2016

6.375% Senior Notes due 2017

6.375% Senior Notes due 2017

7.050% Debentures due 2018

7.050% Debentures due 2018

WES 2.600% Senior Notes due 2018

WES 2.600% Senior Notes due 2018

6.950% Senior Notes due 2019

6.950% Senior Notes due 2019

8.700% Senior Notes due 2019

8.700% Senior Notes due 2019

WES 5.375% Senior Notes due 2021

WES 5.375% Senior Notes due 2021

WES 4.000% Senior Notes due 2022

WES 4.000% Senior Notes due 2022

6.950% Senior Notes due 2024

6.950% Senior Notes due 2024

7.500% Debentures due 2026

7.500% Debentures due 2026

7.000% Debentures due 2027

7.000% Debentures due 2027

7.125% Debentures due 2027

7.125% Debentures due 2027

6.625% Debentures due 2028

6.625% Debentures due 2028

7.150% Debentures due 2028

7.150% Debentures due 2028

7.200% Debentures due 2029

7.200% Debentures due 2029

7.950% Debentures due 2029

7.950% Debentures due 2029

7.500% Senior Notes due 2031

7.500% Senior Notes due 2031

7.875% Senior Notes due 2031

7.875% Senior Notes due 2031

Zero-Coupon Senior Notes due 2036

Zero-Coupon Senior Notes due 2036

6.450% Senior Notes due 2036

6.450% Senior Notes due 2036

7.950% Senior Notes due 2039

7.950% Senior Notes due 2039

6.200% Senior Notes due 2040

6.200% Senior Notes due 2040

7.730% Debentures due 2096

7.730% Debentures due 2096

7.500% Debentures due 2096

7.500% Debentures due 2096

7.250% Debentures due 2096

7.250% Debentures due 2096

Western Gas Partners, LP [Member]

Western Gas Partners, LP [Member]

Western Gas Partners, LP [Member]

Western Gas Partners, LP [Member]

Western Gas Partners, LP [Member]

Western Gas Partners, LP [Member]

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Principal

$15,202

$14,952

'

$275

$275

$500

$500

$1,750

$1,750

$2,000

$2,000

$114

$114

$250

$0

$300

$300

$600

$600

$500

$500

$670

$670

$650

$650

$112

$112

$54

$54

$150

$150

$17

$17

$235

$235

$135

$135

$117

$117

$900

$900

$500

$500

$2,360

$2,360

$1,750

$1,750

$325

$325

$750

$750

$61

$61

$78

$78

$49

$49

Debt instrument, stated interest rate

'

'

'

5.75%

'

7.63%

'

5.95%

'

6.38%

'

7.05%

'

2.60%

'

6.95%

'

8.70%

'

5.38%

'

4.00%

'

6.95%

'

7.50%

'

7.00%

'

7.13%

'

6.63%

'

7.15%

'

7.20%

'

7.95%

'

7.50%

'

7.88%

'

'

'

6.45%

'

7.95%

'

6.20%

'

7.73%

'

7.50%

'

7.25%

'

Debt instrument, maturity date

'

'

'

15-Jun-14

'

15-Mar-14

'

15-Sep-16

'

15-Sep-17

'

15-May-18

'

15-Aug-18

'

15-Jun-19

'

15-Mar-19

'

1-Jun-21

'

1-Jun-22

'

1-Jun-24

'

15-Oct-26

'

15-Nov-27

'

15-Oct-27

'

15-Jan-28

'

15-May-28

'

15-Mar-29

'

15-Apr-29

'

1-May-31

'

15-Sep-31

'

10-Oct-36

'

15-Sep-36

'

15-Jun-39

'

15-Mar-40

'

15-Sep-96

'

1-Nov-96

'

15-Nov-96

'

Net unamortized discounts and premiums (1)

-1,645

[1]

-1,683

[1]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total borrowings

13,557

13,269

15,230

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

727

'

'

'

'

'

'

'

'

'

'

'

'

'

Capital lease obligation

8

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Current portion of long-term debt

500

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total long-term debt

$13,065

$13,269

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

[1]

Unamortized discounts and premiums are amortized over the term of the related debt.

Debt_and_Interest_Expense_Addi

Debt and Interest Expense - Additional Information (Detail) (USD $)

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2006

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Zero-Coupon Senior Notes due 2036

Zero-Coupon Senior Notes due 2036

Zero-Coupon Senior Notes due 2036

5.750% Senior Notes due 2014

5.750% Senior Notes due 2014

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Market Approach Valuation Technique [Member]

Market Approach Valuation Technique [Member]

Western Gas Partners, LP [Member]

Minimum [Member]

Minimum [Member]

Maximum [Member]

Maximum [Member]

London Interbank Offered Rate (LIBOR) [Member]

London Interbank Offered Rate (LIBOR) [Member]

London Interbank Offered Rate (LIBOR) [Member]

London Interbank Offered Rate (LIBOR) [Member]

Western Gas Partners, LP [Member]

Western Gas Partners, LP [Member]

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of credit, maximum capacity

'

'

'

'

'

'

'

'

'

'

$5,000,000,000

$800,000,000

'

'

'

'

Loan proceeds upon issuing debt

'

'

'

'

'

'

500,000,000

'

'

'

'

'

'

'

'

'

Debt instrument, maturity date

'

'

'

'

'

10-Oct-36

'

'

15-Jun-14

'

'

'

'

'

'

'

Debt Instrument, face amount

15,202,000,000

14,952,000,000

'

'

'

2,360,000,000

'

2,360,000,000

275,000,000

275,000,000

'

'

'

'

'

'

Yield to maturity

'

'

'

'

'

5.24%

'

'

'

'

'

'

'

'

'

'

Debt instrument, accreted value

13,557,000,000

13,269,000,000

15,230,000,000

'

'

727,000,000

'

'

'

'

'

'

'

'

'

'

Debt instrument, stated interest rate

'

'

'

'

'

'

'

'

5.75%

'

'

'

'

'

'

'

Debt instrument, earliest call date

'

'

'

'

'

10-Oct-14

'

'

'

'

'

'

'

'

'

'

Total borrowings, fair value

'

'

'

$15,300,000,000

$16,200,000,000

'

'

'

'

'

'

'

'

'

'

'

Line of credit, expiration date

'

'

'

'

'

'

'

'

'

'

2-Sep-15

24-Mar-16

'

'

'

'

Margin added to LIBOR

'

'

'

'

'

'

'

'

'

'

'

'

1.25%

1.30%

2.50%

1.90%

Percentage of capital stock of certain wholly owned foreign subsidiaries

'

'

'

'

'

'

'

'

'

'

65.00%

'

'

'

'

'

Debt_and_Interest_Expense_Subs

Debt and Interest Expense - Subsequent Events (Details) (Revolving Credit Facility [Member], USD $)	12 Months Ended								0 Months Ended
	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Feb. 28, 2014	Feb. 28, 2014	Feb. 28, 2014
		Minimum [Member]	Maximum [Member]	Western Gas Partners, LP [Member]	Western Gas Partners, LP [Member]	Western Gas Partners, LP [Member]	Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]
		London Interbank Offered Rate (LIBOR) [Member]	London Interbank Offered Rate (LIBOR) [Member]		Minimum [Member]	Maximum [Member]	Western Gas Partners, LP [Member]	Western Gas Partners, LP [Member]	Western Gas Partners, LP [Member]	Western Gas Partners, LP [Member]
					London Interbank Offered Rate (LIBOR) [Member]	London Interbank Offered Rate (LIBOR) [Member]			Minimum [Member]	Maximum [Member]
									London Interbank Offered Rate (LIBOR) [Member]	London Interbank Offered Rate (LIBOR) [Member]
Subsequent Event [Line Items]	'	'	'	'	'	'	'	'	'	'
Line of credit, maximum capacity	$5,000,000,000	'	'	$800,000,000	'	'	'	$1,200,000,000	'	'
Line of credit, expiration date	2-Sep-15	'	'	24-Mar-16	'	'	26-Feb-19	'	'	'
Line of credit, expandable maximum capacity	'	'	'	'	'	'	'	$1,500,000,000	'	'
Margin added to LIBOR	'	1.25%	2.50%	'	1.30%	1.90%	'	'	0.98%	1.45%

Debt_and_Interest_Expense_Debt

Debt and Interest Expense - Debt Activity Table (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument, Increase (Decrease), Net [Abstract]	'	'	'
Carrying value, beginning balance	$13,269	$15,230	'
Debt Instrument [Line Items]	'	'	'
Repayments of Debt	-710	-3,044	-1,154
Other, net	38	35	'
Carrying value, ending balance	13,557	13,269	15,230
6.125% Senior Notes due 2012	'	'	'
Debt Instrument [Line Items]	'	'	'
Repayments of Debt	'	-131	'
Debt instrument, stated interest rate	'	6.13%	'
Debt instrument, maturity date	'	15-Mar-12	'
5.000% Senior Notes due 2012	'	'	'
Debt Instrument [Line Items]	'	'	'
Repayments of Debt	'	-39	'
Debt instrument, stated interest rate	'	5.00%	'
Debt instrument, maturity date	'	1-Oct-12	'
Revolving Credit Facility [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Repayments of credit facilities	'	-2,500	'
Western Gas Partners, LP [Member] | WES 4.000% Senior Notes due 2022	'	'	'
Debt Instrument [Line Items]	'	'	'
Issuance	'	674	'
Debt instrument, stated interest rate	4.00%	'	'
Debt instrument, maturity date	1-Jun-22	'	'
Western Gas Partners, LP [Member] | WES 2.600% Senior Notes due 2018	'	'	'
Debt Instrument [Line Items]	'	'	'
Issuance	250	'	'
Debt instrument, stated interest rate	2.60%	'	'
Debt instrument, maturity date	15-Aug-18	'	'
Western Gas Partners, LP [Member] | Revolving Credit Facility [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Borrowings	710	374	'
Repayments of credit facilities	($710)	($374)	'

Debt_and_Interest_Expense_Sche

Debt and Interest Expense - Scheduled Maturities Table (Detail) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Maturities of Long-term Debt and Capital Lease Obligations [Abstract]	'
2014	$775
2015	0
2016	1,750
2017	2,000
2018	$364

Debt_and_Interest_Expense_Inte

Debt and Interest Expense - Interest Expense Table (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Interest Expense [Abstract]	'	'	'
Current debt, long-term debt, and other	$949	$963	$986
Capitalized interest	-263	-221	-147
Interest expense	$686	$742	$839

Stockholders_Equity_Common_Sto

Stockholders' Equity - Common Stock Rollforward (Detail)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Shares of common stock issued	'	'	'
Shares at January 1	518.6	516	513
Exercise of stock options	2	1	1
Issuance of restricted stock	2	2	2
Shares at December 31	522.5	518.6	516
Shares of common stock held in treasury	'	'	'
Shares at January 1	18.1	18	17
Shares received for restricted stock vested and options exercised	1	0	1
Shares at December 31	18.8	18.1	18
Shares of common stock outstanding at December 31	504	501	498

Stockholders_Equity_Reconcilia

Stockholders' Equity - Reconciliation between Basic and Diluted EPS Table (Detail) (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Net income (loss)	'		'		'
Net income (loss) attributable to common stockholders	$801		$2,391		($2,649)
Less distributions on participating securities	2		1		0
Less undistributed income allocated to participating securities	4		14		0
Basic	795		2,376		-2,649
Diluted	$795		$2,376		($2,649)
Shares	'		'		'
Average number of common shares outstanding—basic	502		500		498
Dilutive effect of stock options	3		2		0
Average number of common shares outstanding—diluted	505		502		498
Excluded (1)	4	[1]	6	[1]	12	[1]
Net income (loss) per common share	'		'		'
Basic	$1.58		$4.76		($5.32)
Diluted	$1.58		$4.74		($5.32)
Dividends per common share	$0.54		$0.36		$0.36
[1]	Inclusion of certain shares would have had an anti-dilutive effect.

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Loss) (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Balance at December 31, 2012	($640)	'	'
Other comprehensive income (loss), before reclassifications	264	'	'
Reclassifications to Consolidated Statement of Income	91	'	'
Net other comprehensive income (loss)	355	-28	-63
Balance at December 31, 2013	-285	-640	'
Interest-rate Derivatives Previously Subject to Hedge Accounting [Member]	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Balance at December 31, 2012	-61	'	'
Other comprehensive income (loss), before reclassifications	0	'	'
Reclassifications to Consolidated Statement of Income	7	'	'
Net other comprehensive income (loss)	7	'	'
Balance at December 31, 2013	-54	'	'
Pension and Other Postretirement Plans [Member]	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'
Balance at December 31, 2012	-579	'	'
Other comprehensive income (loss), before reclassifications	264	'	'
Reclassifications to Consolidated Statement of Income	84	'	'
Net other comprehensive income (loss)	348	'	'
Balance at December 31, 2013	($231)	'	'

ShareBased_Compensation_Genera

Share-Based Compensation - General (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Arrangements with Employees and Nonemployees [Abstract]	'	'	'
Shares available for future issuance under active share-based compensation plans	26	'	'
Shares authorized for awards under active share-based compensation plans	31	'	'
Excess tax benefits related to share-based compensation included in cash flows from financing activities	$11	$51	($15)
Cash received from stock option exercises	$135	$52	$45

ShareBased_Compensation_Compen

Share-Based Compensation - Compensation Expense Table (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'
Pretax compensation expense	$155	$320	$215
Income tax benefit	57	117	78
Equity-Classified Awards [Member]	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'
Pretax compensation expense	150	147	132
Liability-Classified Awards [Member]	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'
Pretax compensation expense	5	173	83
Restricted Stock [Member] | Equity-Classified Awards [Member]	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'
Pretax compensation expense	122	103	80
Stock Option [Member] | Equity-Classified Awards [Member]	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'
Pretax compensation expense	27	43	51
Performance-Based Share Awards and Other [Member] | Equity-Classified Awards [Member]	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'
Pretax compensation expense	1	1	1
Value Creation Plan [Member] | Liability-Classified Awards [Member]	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'
Pretax compensation expense	0	-2	26
Performance-Based Unit Awards [Member] | Liability-Classified Awards [Member]	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'
Pretax compensation expense	4	8	28
Other Performance-Based Awards [Member] | Liability-Classified Awards [Member]	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'
Pretax compensation expense	0	165	28
Other [Member] | Liability-Classified Awards [Member]	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'
Pretax compensation expense	$1	$2	$1

ShareBased_Compensation_Equity

Share-Based Compensation - Equity-Classified Awards (Detail) (USD $)	12 Months Ended			72 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'	'
Shares of common stock authorized	31,000,000	'	'	31,000,000
Restricted Stock [Member]	'	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'	'
Weighted-average grant-date fair value	$84.17	$79.97	$81.19	'
Total fair value	$110,000,000	$105,000,000	$124,000,000	'
Total unrecognized compensation cost	175,000,000	'	'	175,000,000
Unrecognized compensation cost, weighted-average remaining period	'1 year 10 months 24 days	'	'	'
Restricted Stock [Member] | Maximum [Member]	'	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'	'
Vesting period	'3 years	'	'	'
Stock Option [Member]	'	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'	'
Vesting period	'3 years	'	'	'
Unrecognized compensation cost, weighted-average remaining period	'2 years 2 months 12 days	'	'	'
Weighted-average grant-date fair value	$26.27	$25.84	$29.77	'
Total intrinsic value of stock options exercised during the period	80,000,000	49,000,000	45,000,000	'
Total unrecognized compensation cost related to stock options	41,000,000	'	'	41,000,000
Stock Option [Member] | Maximum [Member]	'	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'	'
Expiration date	'7 years	'	'	'
Performance-Based Share Awards [Member]	'	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'	'
Total fair value	11,000,000	0	6,000,000	'
Total unrecognized compensation cost	$0	'	'	$0
Shares earned	'	'	'	521,258
Shares available to be earned in the future	0	'	'	'
Shares issued	'	'	'	506,449
Shares deferred pursuant to the agreements	'	'	'	14,809
Performance-Based Share Awards [Member] | Minimum [Member]	'	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'	'
Vesting period	'1 year	'	'	'
Performance-Based Share Awards [Member] | Maximum [Member]	'	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'	'
Vesting period	'3 years	'	'	'
Shares of common stock authorized	934,424	'	'	934,424

ShareBased_Compensation_Restri

Share-Based Compensation - Restricted Stock Activity Table (Detail) (Restricted Stock [Member], USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restricted Stock [Member]	'	'	'
Restricted Stock Shares [Abstract]	'	'	'
Non-vested at January 1, 2013	2.82	'	'
Granted	1.88	'	'
Vested	-1.32	'	'
Forfeited	-0.16	'	'
Non-vested at December 31, 2013	3.22	2.82	'
Restricted Stock Weighted-Average Grant-Date Fair Value [Abstract]	'	'	'
Non-vested at January 1, 2013	$79.27	'	'
Granted	$84.17	$79.97	$81.19
Vested	$78.19	'	'
Forfeited	$80.37	'	'
Non-vested at December 31, 2013	$82.53	$79.27	'

ShareBased_Compensation_Stock_

Share-Based Compensation - Stock Options Assumptions Table (Detail) (Stock Option [Member])	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock Option [Member]	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'
Expected option life—years	'4 years 9 months 18 days	'4 years 10 months 24 days	'4 years 9 months 18 days
Volatility	33.90%	44.20%	42.00%
Risk-free interest rate	1.30%	0.70%	1.50%
Dividend yield	0.80%	0.50%	0.50%

ShareBased_Compensation_Stock_1

Share-Based Compensation - Stock Option Activity Table (Detail) (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward]	'	'	'
Shares exercised	-2	-1	-1
Stock Option [Member]	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward]	'	'	'
Shares outstanding at January 1, 2013	9.36	'	'
Shares granted	0.91	'	'
Shares exercised	-2.43	'	'
Shares forfeited or expired	-0.12	'	'
Shares outstanding at December 31, 2013	7.72	'	'
Shares vested or expected to vest at December 31, 2013	7.65	'	'
Shares exercisable at December 31, 2013	5.87	'	'
Weighted-average exercise price, outstanding at January 1, 2013	58.66	'	'
Granted weighted-average exercise price	91.71	'	'
Exercised weighted-average exercise price	55.59	'	'
Forfeited or expired weighted-average exercise price	74.55	'	'
Weighted-average exercise price, outstanding at December 31, 2013	63.3	'	'
Weighted-average exercise price, vested or expected to vest at December 31, 2013	63.14	'	'
Weighted-average exercise price, exercisable at December 31, 2013	57	'	'
Weighted-average remaining contractual term, outstanding at December 31, 2013	'3 years 7 months 2 days	'	'
Weighted-average remaining contractual term, vested or expected to vest at December 31, 2013	'3 years 6 months 26 days	'	'
Weighted-average remaining contractual term, exercisable at December 31, 2013	'2 years 9 months 29 days	'	'
Aggregate intrinsic value, outstanding at December 31, 2013	138.3	'	'
Aggregate intrinsic value, vested or expected to vest at December 31, 2013	138.2	'	'
Aggregate intrinsic value, exercisable at December 31, 2013	133.5	'	'

ShareBased_Compensation_Liabil

Share-Based Compensation - Liability-Classified Awards (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Value Creation Plan [Member]	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'
Liability paid	$0	$24,000,000	$0
Outstanding liability	0	'	'
Performance-Based Unit Awards [Member]	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'
Liability paid	15,000,000	37,000,000	25,000,000
Outstanding liability	15,000,000	'	'
Number of shares of common stock represented by each performance unit	1	'	'
Total unrecognized compensation cost	20,000,000	'	'
Unrecognized compensation cost, weighted-average remaining period	'1 year 10 months 24 days	'	'
Performance-Based Unit Awards [Member] | Minimum [Member]	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'
Vesting period	'2 years	'	'
Performance-Based Unit Awards [Member] | Maximum [Member]	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'
Vesting period	'3 years	'	'
Other Performance-Based Awards [Member]	'	'	'
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]	'	'	'
Liability paid	'	$203,000,000	'

Commitments_Operating_Leases_D

Commitments - Operating Leases (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Leased Assets [Line Items]	'	'	'
Operating leases, future minimum payments due	$3,690,000,000	'	'
Total rent expense, net of sublease income	119,000,000	136,000,000	143,000,000
Contingent rent expense	17,000,000	18,000,000	21,000,000
Drilling Rigs [Member]	'	'	'
Operating Leased Assets [Line Items]	'	'	'
Operating leases, future minimum payments due	3,300,000,000	'	'
Exploration and Production and Other Operating Lease Agreements [Member]	'	'	'
Operating Leased Assets [Line Items]	'	'	'
Operating leases, future minimum payments due	388,000,000	'	'
Residual value guarantees	53,000,000	'	'
Operating lease, residual value guarantees accrued	0	'	'
Exploration and Production and Other Operating Lease Agreements [Member] | Maximum [Member]	'	'	'
Operating Leased Assets [Line Items]	'	'	'
Operating leases, expiration date	31-Dec-26	'	'
Offshore Drilling Rig Commitments [Member]	'	'	'
Operating Leased Assets [Line Items]	'	'	'
Operating leases, future minimum payments due	3,100,000,000	'	'
Number of drilling vessels related to operating leases	8	'	'
Onshore Drilling Rig Commitments [Member]	'	'	'
Operating Leased Assets [Line Items]	'	'	'
Operating leases, future minimum payments due	155,000,000	'	'
Spar Platform and Production Vessel Leases [Member]	'	'	'
Operating Leased Assets [Line Items]	'	'	'
Operating leases, future minimum payments due	$206,000,000	'	'

Commitments_Future_Minimum_Lea

Commitments - Future Minimum Lease Payments Table (Detail) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Leases, Operating [Abstract]	'
2014	$964
2015	948
2016	755
2017	525
2018	309
Later years	189
Total future minimum lease payments	$3,690

Commitments_Other_Commitments_

Commitments - Other Commitments (Detail) (USD $)	12 Months Ended
In Billions, unless otherwise specified	Dec. 31, 2013
Unrecorded Unconditional Purchase Obligation [Line Items]	'
Aggregate future payments	11.5
Aggregate future payments expected to be paid in 2014	2.3
Aggregate future payments expected to be paid in 2015	1.8
Aggregate future payments expected to be paid in 2016	1.4
Aggregate future payments expected to be paid in 2017	1.2
Aggregate future payments expected to be paid in 2018	1.1
Aggregate future payments expected to be paid thereafter	3.7
Maximum [Member]	'
Unrecorded Unconditional Purchase Obligation [Line Items]	'
Other commitments, expiration date	31-Dec-30

Contingencies_Detail

Contingencies (Detail) (USD $)	12 Months Ended					12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013
				Landfill in West Covina, California [Member]	Algeria Exceptional Profits Tax Settlement [Member]	Third Party Bankruptcy Assignment [Member]	Pending Litigation [Member]	Pending Litigation [Member]	Pending Litigation [Member]
							Peregrino Litigation [Member]	Peregrino Litigation [Member]	Peregrino Litigation [Member]
								Amount Of Tax Originally In Dispute [Member]	Amount Of Tax Currently In Dispute [Member]
Loss Contingencies [Line Items]	'	'	'	'	'	'	'	'	'
Loss contingency accrual	$854,000,000	$49,000,000	'	'	'	'	$0	'	'
Other Assets	2,082,000,000	1,716,000,000	'	'	'	'	'	144,000,000	47,000,000
Algeria exceptional profits tax settlement	0	730,000,000	'	'	1,700,000,000	'	'	'	'
Decommissioning charge	850,000,000	-250,000,000	250,000,000	'	'	117,000,000	'	'	'
Decommissioning obligations included in accrued expenses	'	'	'	'	'	21,000,000	'	'	'
Decommissioning obligations included in other long-term liabilities	850,000,000	0	'	'	'	85,000,000	'	'	'
Liability for remediation and reclamation obligations	$126,000,000	$81,000,000	'	$50,000,000	'	'	'	'	'

Contingencies_Tronox_Litigatio

Contingencies - Tronox Litigation (Detail) (USD $)

12 Months Ended

3 Months Ended

12 Months Ended

21 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Feb. 28, 2014

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Tronox Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Pending Litigation [Member]

Aggregating Kerr-McGee's 502(h) Claim with Class 3 claims [Member]

Bankruptcy Court Memorandum Of Opinion, After Trial [Member]

Bankruptcy Court Memorandum Of Opinion, After Trial [Member]

Bankruptcy Court's finding of net present value of legacy environmental and tort liabilities at IPO date [Member]

Plaintiffs' Requested 502(h) Claim [Member]

Plaintiffs' Alternative Requested Dilution [Member]

Plaintiffs' Alternative Requested Dilution [Member]

Excluding Pre-Judgment Interest Sought and Attorneys' Fees and Costs [Member]

Attorneys' Fees and Costs [Member]

Excluding Attorneys' Fees and Costs [Member]

Pre-Judgment Interest [Member]

Post-Judgment Interest [Member]

Low End of Range of Probable Loss [Member]

Low End of Range of Probable Loss [Member]

Low End of Range of Probable Loss [Member]

Low End of Range of Probable Loss [Member]

High End of Range of Probable Loss [Member]

High End of Range of Probable Loss [Member]

High End of Range of Probable Loss [Member]

High End of Range of Probable Loss [Member]

Aggregating Kerr-McGee's 502(h) Claim with Class 3 claims [Member]

Aggregating Kerr-McGee's 502(h) Claim with Class 3 claims [Member]

Bankruptcy Court Memorandum Of Opinion, After Trial [Member]

Kerr-McGee's 502(h) Claim [Member]

Kerr-McGee's Estimated Entitled Recovery Percentage [Member]

Bankruptcy Court Memorandum Of Opinion, After Trial [Member]

Mid-point in plaintiffs' post-petition estimate of potential legacy environmental and tort liabilities as of 2010 [Member]

Estimated average percentage recovery for Class 3 General Unsecured Creditors [Member]

Loss Contingencies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Tronox-related contingent loss

$850,000,000

($250,000,000)

$250,000,000

($525,000,000)

$275,000,000

$250,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Tronox-related contingent liability

850,000,000

0

'

0

525,000,000

'

850,000,000

'

'

'

'

'

'

'

'

'

0

'

0

0

'

'

'

'

'

'

'

'

Value of transferred assets as of the IPO date

'

'

'

'

'

'

'

'

'

14,459,000,000

'

'

'

'

'

'

'

'

'

'

'

14,459,000,000

[1]

'

'

'

14,459,000,000

[1]

'

'

502(h) Claim

'

'

'

'

'

'

'

'

'

10,459,000,000

293,000,000

'

0

'

'

'

'

'

'

'

'

'

13,609,000,000

'

'

10,459,000,000

'

'

Range of possible loss, minimum

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

850,000,000

'

'

'

'

'

'

'

Legacy environmental and tort liabilities

'

'

'

'

'

'

'

'

'

'

'

-1,757,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-4,000,000,000

'

Recovery Percentage

'

'

'

'

'

'

'

'

2.80%

'

'

'

'

68.00%

2.80%

'

'

'

'

'

'

'

'

100.00%

'

'

'

89.00%

Damages sought

'

'

'

'

'

'

'

20,770,000,000

'

'

'

'

'

'

'

18,850,000,000

'

'

'

'

'

'

'

'

'

'

'

'

Pre-judgment interest rate sought

'

'

'

'

'

'

6.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Range of possible loss, maximum

'

'

'

'

'

'

14,520,000,000

'

14,160,000,000

'

'

'

'

'

'

'

61,000,000

14,459,000,000

'

'

'

'

'

'

'

'

'

'

Range of probable loss, maximum

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5,150,000,000

'

'

'

Offset amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-13,609,000,000

'

'

'

-9,309,000,000

'

'

'

Net Creditor Shortfall

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-850,000,000

'

'

'

'

'

'

'

Post-judgment interest rate

'

'

'

'

'

'

0.13%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Tax benefit recognized on liability accrued percentage

'

'

'

'

'

'

88.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Tronox-related contingent loss

850,000,000

-250,000,000

250,000,000

'

'

'

850,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Deferred tax benefit

($137,000,000)

($159,000,000)

$1,453,000,000

'

'

'

$274,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

[1]

As determined by the Bankruptcy Court.

Contingencies_Deepwater_Horizo

Contingencies - Deepwater Horizon Events (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2011	Feb. 28, 2014	Dec. 31, 2013	Feb. 04, 2014	Dec. 31, 2013	Dec. 31, 2011
			Macondo Exploration Well [Member]	Deepwater Horizon [Member]	Deepwater Horizon [Member]	Deepwater Horizon [Member]	Deepwater Horizon [Member]	Deepwater Horizon [Member]
					Oil Pollution Act of 1990 [Member]	Oil Pollution Act of 1990 [Member]	BP indemnification liability [Member]	BP Settlement Agreement [Member]
						BP Exploration and Production Inc. [Member]
Loss Contingencies [Line Items]	'	'	'	'	'	'	'	'
Anadarko's nonoperated interest	'	'	25.00%	'	'	'	'	'
Cash payment for Deepwater Horizon settlement	'	'	'	'	'	'	'	$4,000,000,000
Loss contingency accrual	854,000,000	49,000,000	'	'	'	'	0	'
Gross OPA-related environmental costs, excluding amounts BP has already funded, amounts that cannot reasonably be estimated by BP, non-OPA-related fines and penalties, and estimated state and local governmental claims	'	'	'	'	'	10,900,000,000	'	'
Allocable percentage share of gross OPA-related environmental costs	'	'	'	'	0.00%	'	'	'
Accrual for environmental loss contingencies	126,000,000	81,000,000	'	'	0	'	'	'
Penalties or fines assessed against the Company	'	'	'	$0	'	'	'	'

Other_Taxes_Detail

Other Taxes (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Taxes, Miscellaneous [Abstract]	'	'	'
Production and severance	$706	$855	$1,094
Ad valorem	277	238	265
Other	94	131	133
Total	$1,077	$1,224	$1,492

Income_Taxes_Components_of_Inc

Income Taxes - Components of Income Tax Table (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current [Abstract]	'	'	'
Federal	$113	$45	($381)
State	42	25	1
Foreign	873	891	977
Total	1,028	961	597
Deferred [Abstract]	'	'	'
Federal	94	-30	-1,470
State	-9	115	-68
Foreign	52	74	85
Total	137	159	-1,453
Income tax expense (benefit)	$1,165	$1,120	($856)

Income_Taxes_Reconciliation_of

Income Taxes - Reconciliation of Tax Computed at the U.S. Federal Statutory Rate to Income Tax Expense (Benefit) Table (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income (loss) before income taxes	'	'	'
Domestic	$428	$132	($5,416)
Foreign	1,678	3,433	1,992
Income (Loss) Before Income Taxes	2,106	3,565	-3,424
U.S. federal statutory tax rate	35.00%	35.00%	35.00%
Tax computed at the U.S. federal statutory rate	737	1,248	-1,198
Adjustments resulting from	'	'	'
State income taxes (net of federal income tax benefit)	23	93	-44
Tax impact from foreign operations	167	226	93
Effective Income Tax Rate Reconciliation [Line Items]	'	'	'
Non-taxable Algeria exceptional profits tax settlement	13	-679	0
Income attributable to noncontrolling interests	-48	-24	-28
Other—net	17	46	39
Income tax expense (benefit)	1,165	1,120	-856
Effective tax rate	55.00%	31.00%	25.00%
Pending Litigation [Member] | Tronox Litigation [Member]	'	'	'
Effective Income Tax Rate Reconciliation [Line Items]	'	'	'
Non-deductible expense	36	0	0
Algerian Exceptional Profits Tax [Member]	'	'	'
Effective Income Tax Rate Reconciliation [Line Items]	'	'	'
Non-deductible expense	144	188	258
Deferred Tax Adjustments [Member]	'	'	'
Effective Income Tax Rate Reconciliation [Line Items]	'	'	'
Other adjustments	76	22	5
Items Resulting From Business Acquisitions [Member]	'	'	'
Effective Income Tax Rate Reconciliation [Line Items]	'	'	'
Other adjustments	$0	$0	$19

Income_Taxes_Components_of_Tot

Income Taxes - Components of Total Deferred Taxes Table (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Deferred Tax Assets (Liabilities), Net [Line Items]	'	'
Total deferred taxes	($8,885)	($8,431)
Federal [Member]	'	'
Deferred Tax Assets (Liabilities), Net [Line Items]	'	'
Total deferred taxes	-8,246	-7,890
State, net of federal [Member]	'	'
Deferred Tax Assets (Liabilities), Net [Line Items]	'	'
Total deferred taxes	-332	-325
Foreign [Member]	'	'
Deferred Tax Assets (Liabilities), Net [Line Items]	'	'
Total deferred taxes	($307)	($216)

Income_Taxes_Deferred_Tax_Asse

Income Taxes - Deferred Tax Assets (Liabilities) Table (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
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)

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Line Items]	'	'	'
Unrecognized tax benefits that would affect the effective tax rate on income if recognized	($129)	'	'
Increase in valuation allowance expected to offset a portion of the potential tax benefit	99	'	'
Unrecognized tax benefits related to tax positions for which ultimate deductibility is highly certain, but timing is uncertain	-18	'	'
The lower range of unrecognized tax benefits expected to reverse within the next 12 months due to expiration of statutes of limitation and audit settlements	-4	'	'
The higher range of unrecognized tax benefits expected to reverse within the next 12 months due to expiration of statutes of limitation and audit settlements	-10	'	'
Accrued interest related to uncertain tax positions	8	28	'
Interest and penalties recognized in income tax expense (benefit)	-20	9	'
U.S. Internal Revenue Service [Member] | Minimum [Member]	'	'	'
Income Tax Disclosure [Line Items]	'	'	'
Tax year currently under routine examination	'2007	'	'
U.S. Internal Revenue Service [Member] | Maximum [Member]	'	'	'
Income Tax Disclosure [Line Items]	'	'	'
Tax year currently under routine examination	'2013	'	'
Additions [Member]	'	'	'
Income Tax Disclosure [Line Items]	'	'	'
(Increase) decrease in valuation allowances	-38	-426	-138
Reductions [Member]	'	'	'
Income Tax Disclosure [Line Items]	'	'	'
(Increase) decrease in valuation allowances	142	59	37
Changes in Judgment Regarding Future Realizability of Deferred Tax Assets [Member] | Additions [Member]	'	'	'
Income Tax Disclosure [Line Items]	'	'	'
(Increase) decrease in valuation allowances	-2	-23	'
Changes in Judgment Regarding Future Realizability of Deferred Tax Assets [Member] | Reductions [Member]	'	'	'
Income Tax Disclosure [Line Items]	'	'	'
(Increase) decrease in valuation allowances	'	'	$17

Income_Taxes_Valuation_Allowan

Income Taxes - Valuation Allowances Rollforward (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Millions, unless otherwise specified					Additions [Member]	Additions [Member]	Additions [Member]	Reductions [Member]	Reductions [Member]	Reductions [Member]
Valuation Allowance [Abstract]	'	'	'	'	'	'	'	'	'	'
Balance at January 1	($818)	($922)	($555)	($454)	'	'	'	'	'	'
Valuation Allowance [Line Items]	'	'	'	'	'	'	'	'	'	'
Change in valuation allowances	'	'	'	'	-38	-426	-138	142	59	37
Balance at December 31	($818)	($922)	($555)	($454)	'	'	'	'	'	'

Income_Taxes_Taxes_Receivable_

Income Taxes - Taxes Receivable (Payable) Table (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Components of Income Tax Receivable (Payable) [Line Items]	'	'
Income taxes receivable	$101	$181
Net income taxes receivable (payable)	19	143
Accounts Receivable - Other [Member]	'	'
Components of Income Tax Receivable (Payable) [Line Items]	'	'
Income taxes receivable	66	179
Other Assets [Member]	'	'
Components of Income Tax Receivable (Payable) [Line Items]	'	'
Income taxes receivable	35	2
Accrued Expense [Member]	'	'
Components of Income Tax Receivable (Payable) [Line Items]	'	'
Income taxes (payable)	($82)	($38)

Income_Taxes_Tax_Carryforwards

Income Taxes - Tax Carryforwards Table (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013
Foreign Tax Credits [Member]	'
Tax Carryforwards [Line Items]	'
Tax credit carryforward	325
Foreign Tax Credits [Member] | Minimum [Member]	'
Tax Carryforwards [Line Items]	'
Tax credit carryforward, expiration date(s)	31-Dec-15
Foreign Tax Credits [Member] | Maximum [Member]	'
Tax Carryforwards [Line Items]	'
Tax credit carryforward, expiration date(s)	31-Dec-23
Texas Margins Tax Credit [Member]	'
Tax Carryforwards [Line Items]	'
Tax credit carryforward	35
Tax credit carryforward, expiration date(s)	31-Dec-26
Foreign [Member]	'
Tax Carryforwards [Line Items]	'
Net operating loss carryforward	1,265
Foreign [Member] | Minimum [Member]	'
Tax Carryforwards [Line Items]	'
Net operating loss carryforwards, expiration date(s)	31-Dec-14
State [Member]	'
Tax Carryforwards [Line Items]	'
Net operating loss carryforward	4,527
State [Member] | Minimum [Member]	'
Tax Carryforwards [Line Items]	'
Net operating loss carryforwards, expiration date(s)	31-Dec-14
State [Member] | Maximum [Member]	'
Tax Carryforwards [Line Items]	'
Net operating loss carryforwards, expiration date(s)	31-Dec-32

Income_Taxes_Unrecognized_Tax_

Income Taxes - Unrecognized Tax Benefits Rollforward (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Uncertainties [Abstract]	'	'	'
Balance at January 1	($46)	($31)	($32)
Increases related to prior-year tax positions	-54	-17	0
Decreases related to prior-year tax positions	3	3	3
Increases related to current-year tax positions	-72	-1	-10
Settlements	5	0	8
Lapse of statute of limitations	17	0	0
Balance at December 31	($147)	($46)	($31)

Income_Taxes_Tax_Years_Subject

Income Taxes - Tax Years Subject to Examination by Major Jurisdiction Table (Detail)	12 Months Ended
	Dec. 31, 2013
United States [Member] | Minimum [Member]	'
Income TaxExamination [Line Items]	'
Tax year subject to examination	'2007
United States [Member] | Maximum [Member]	'
Income TaxExamination [Line Items]	'
Tax year subject to examination	'2013
China [Member] | Minimum [Member]	'
Income TaxExamination [Line Items]	'
Tax year subject to examination	'2009
China [Member] | Maximum [Member]	'
Income TaxExamination [Line Items]	'
Tax year subject to examination	'2013
Algeria [Member] | Minimum [Member]	'
Income TaxExamination [Line Items]	'
Tax year subject to examination	'2010
Algeria [Member] | Maximum [Member]	'
Income TaxExamination [Line Items]	'
Tax year subject to examination	'2013
Ghana [Member] | Minimum [Member]	'
Income TaxExamination [Line Items]	'
Tax year subject to examination	'2006
Ghana [Member] | Maximum [Member]	'
Income TaxExamination [Line Items]	'
Tax year subject to examination	'2013

Supplemental_Cash_Flow_Informa2

Supplemental Cash Flow Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash paid (received)	'	'	'
Interest	$627	$684	$806
Income taxes	169	-300	262
Non-cash investing activities	'	'	'
Fair value of properties and equipment exchanged in non-cash transactions	62	65	19
Non-cash investing and financing activities	'	'	'
Capital lease obligation	8	0	'
Floating production, storage, and offloading vessel construction period obligation	17	0	0
Capital Lease Obligation [Member]	'	'	'
Other Significant Noncash Transactions [Line Items]	'	'	'
Capital lease obligation	'	'	-118
Wattenberg Natural-Gas Processing Plant [Member]	'	'	'
Business Acquisition [Line Items]	'	'	'
Gain related to the fair-value remeasurement of Anadarko’s pre-acquisition 7% equity interest in the Wattenberg Plant	$0	$0	$21
Business combination, equity interest in acquiree, percentage	'	'	7.00%

Segment_Information_Additional

Segment Information - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	Segment
Segment Reporting [Abstract]	'	'	'
Number of reporting segments	3	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	$14,581,000,000	$13,411,000,000	$13,967,000,000
Midstream Reporting Segment [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Number of operating segments	2	'	'
Total S.A. [Member] | Oil and Gas Exploration and Production Reporting Segment [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	2,000,000,000	1,900,000,000	'
Major Customer [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	'	'	$0

Segment_Information_Reconcilia

Segment Information - Reconciliation of Consolidated Adjusted EBITDAX to Income (Loss) before Income Taxes Table (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract]	'	'	'
Income (loss) before income taxes	$2,106	$3,565	($3,424)
Exploration expense	1,329	1,946	1,076
DD&A	3,927	3,964	3,830
Impairments	794	389	1,774
Interest expense	686	742	839
Total (gains) losses on derivatives, net, less net cash received in settlement of commodity derivatives	-307	443	675
Deepwater Horizon settlement and related costs	15	18	3,930
Algeria exceptional profits tax settlement	33	-1,797	0
Segment Reporting Information [Line Items]	'	'	'
Tronox-related contingent loss	850	-250	250
Certain other nonoperating items	850	-250	250
Less net income attributable to noncontrolling interests	140	54	81
Consolidated Adjusted EBITDAX	9,403	8,966	8,869
Certain Other Nonoperating Items [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Certain other nonoperating items	$110	$0	$0

Segment_Information_Selected_F

Segment Information - Selected Financial Information for Anadarko's Reporting Segments Table (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Segment Reporting Information [Line Items]	'		'		'
Revenues	$14,867,000,000		$13,307,000,000		$13,882,000,000
Gains (losses) on divestitures and other, net	-286,000,000		104,000,000		85,000,000
Total revenues and other	14,581,000,000		13,411,000,000		13,967,000,000
Operating costs and expenses (1)	5,150,000,000	[1]	5,164,000,000	[1]	5,227,000,000	[1]
Net cash received in settlement of commodity derivatives	-85,000,000		-685,000,000		-147,000,000
Other (income) expense, net	89,000,000		-4,000,000		4,000,000
Net income attributable to noncontrolling interests	140,000,000		54,000,000		81,000,000
Total expenses and other	5,174,000,000		4,461,000,000		5,086,000,000
Adjusted EBITDAX	9,403,000,000		8,966,000,000		8,869,000,000
Net properties and equipment	40,929,000,000		38,398,000,000		37,501,000,000
Capital expenditures	8,523,000,000		7,311,000,000		6,553,000,000
Goodwill	5,492,000,000		5,492,000,000		5,641,000,000
(Gains) Losses on Derivatives, net [Member] | Commodity Contract [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Net cash received in settlement of commodity derivatives	-95,000,000		-753,000,000		-226,000,000
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 received in settlement	-4,000,000		16,000,000		-12,000,000
Excluding Certain Other Nonoperating Items [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Other (income) expense, net	-21,000,000	[2]	-4,000,000	[2]	4,000,000	[2]
Other and Intersegment Eliminations [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Revenues	0		0		-2,000,000
Gains (losses) on divestitures and other, net	337,000,000		177,000,000		139,000,000
Total revenues and other	-314,000,000		-366,000,000		-310,000,000
Operating costs and expenses (1)	20,000,000	[1]	295,000,000	[1]	186,000,000	[1]
Total expenses and other	-96,000,000		-462,000,000		-36,000,000
Adjusted EBITDAX	-218,000,000		96,000,000		-274,000,000
Net properties and equipment	2,103,000,000		1,906,000,000		1,825,000,000
Capital expenditures	267,000,000		155,000,000		107,000,000
Goodwill	0		0		0
Other and Intersegment Eliminations [Member] | (Gains) Losses on Derivatives, net [Member] | Commodity Contract [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Net cash received in settlement of commodity derivatives	-95,000,000		-753,000,000		-226,000,000
Other and Intersegment Eliminations [Member] | Excluding Certain Other Nonoperating Items [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Other (income) expense, net	-21,000,000	[2]	-4,000,000	[2]	4,000,000	[2]
Other and Intersegment Eliminations [Member] | Intersegment Revenues [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Revenues	-651,000,000		-543,000,000		-447,000,000
Oil and Gas Exploration and Production Reporting Segment [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Revenues	7,090,000,000		6,752,000,000		7,519,000,000
Gains (losses) on divestitures and other, net	-622,000,000		-65,000,000		-41,000,000
Oil and Gas Exploration and Production Reporting Segment [Member] | Intersegment Revenues [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Revenues	6,405,000,000		5,318,000,000		5,005,000,000
Oil and Gas Exploration and Production Reporting Segment [Member] | Operating Segments [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Total revenues and other	12,873,000,000		12,005,000,000		12,483,000,000
Operating costs and expenses (1)	3,635,000,000	[1]	3,505,000,000	[1]	3,696,000,000	[1]
Total expenses and other	3,635,000,000		3,505,000,000		3,696,000,000
Adjusted EBITDAX	9,238,000,000		8,500,000,000		8,787,000,000
Net properties and equipment	33,409,000,000		32,024,000,000		32,235,000,000
Capital expenditures	7,008,000,000		5,906,000,000		5,026,000,000
Goodwill	5,317,000,000		5,317,000,000		5,475,000,000
Midstream Reporting Segment [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Revenues	387,000,000		325,000,000		342,000,000
Gains (losses) on divestitures and other, net	-1,000,000		-8,000,000		-13,000,000
Midstream Reporting Segment [Member] | Intersegment Revenues [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Revenues	1,105,000,000		959,000,000		957,000,000
Midstream Reporting Segment [Member] | Operating Segments [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Total revenues and other	1,491,000,000		1,276,000,000		1,286,000,000
Operating costs and expenses (1)	843,000,000	[1]	748,000,000	[1]	786,000,000	[1]
Net income attributable to noncontrolling interests	140,000,000		54,000,000		81,000,000
Total expenses and other	983,000,000		802,000,000		867,000,000
Adjusted EBITDAX	508,000,000		474,000,000		419,000,000
Net properties and equipment	5,408,000,000		4,459,000,000		3,432,000,000
Capital expenditures	1,248,000,000		1,250,000,000		1,420,000,000
Goodwill	175,000,000		175,000,000		166,000,000
Marketing Reporting Segment [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Revenues	7,390,000,000		6,230,000,000		6,023,000,000
Gains (losses) on divestitures and other, net	0		0		0
Marketing Reporting Segment [Member] | Intersegment Revenues [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Revenues	-6,859,000,000		-5,734,000,000		-5,515,000,000
Marketing Reporting Segment [Member] | Operating Segments [Member]	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Total revenues and other	531,000,000		496,000,000		508,000,000
Operating costs and expenses (1)	652,000,000	[1]	616,000,000	[1]	559,000,000	[1]
Total expenses and other	652,000,000		616,000,000		559,000,000
Adjusted EBITDAX	-125,000,000		-104,000,000		-63,000,000
Net properties and equipment	9,000,000		9,000,000		9,000,000
Capital expenditures	0		0		0
Goodwill	0		0		0
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 received in settlement	($4,000,000)		$16,000,000		($12,000,000)
[1]	Operating costs and expenses exclude 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 Tronox-related contingent loss since this expense is excluded from Adjusted EBITDAX.

Segment_Information_Sales_Reve

Segment Information - Sales Revenues by Geographic Area Table (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue from External Customer [Line Items]	'	'	'
Sales revenues	$14,867	$13,307	$13,882
United States [Member]	'	'	'
Revenue from External Customer [Line Items]	'	'	'
Sales revenues	11,290	9,911	10,477
Algeria [Member]	'	'	'
Revenue from External Customer [Line Items]	'	'	'
Sales revenues	2,184	2,182	2,258
Other International [Member]	'	'	'
Revenue from External Customer [Line Items]	'	'	'
Sales revenues	$1,393	$1,214	$1,147

Segment_Information_Net_Proper

Segment Information - Net Properties and Equipment by Geographic Area Table (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Millions, unless otherwise specified
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'
Net properties and equipment	$40,929	$38,398	$37,501
United States [Member]	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'
Net properties and equipment	35,486	33,337	'
Algeria [Member]	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'
Net properties and equipment	1,582	1,575	'
Other International [Member]	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'
Net properties and equipment	$3,861	$3,486	'

Pension_Plans_Other_Postretire3

Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Defined-benefit plan, amortization of net actuarial loss in 2014	$26,000,000	'	'
Defined-benefit plan, health care cost trend rate assumed for next fiscal year	8.00%	8.00%	'
Defined-benefit plan, ultimate health care cost trend rate	5.00%	'	'
Defined benefit plan, amount of employer securities included in plan assets	0	'	'
Defined-contribution plans, recognized expense	78,000,000	55,000,000	41,000,000
Equity Securities [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Defined-benefit plan, target asset-allocation range, minimum	45.00%	'	'
Defined-benefit plan, target asset-allocation range, maximum	55.00%	'	'
Fixed Income [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Defined-benefit plan, target asset-allocation range, minimum	20.00%	'	'
Defined-benefit plan, target asset-allocation range, maximum	30.00%	'	'
Other Investments [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Defined-benefit plan, target asset-allocation range, maximum	25.00%	'	'
Pension Plans, Defined Benefit [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Employer contributions	160,000,000	107,000,000	'
Pension Plans, Defined Benefit [Member] | Funded Plans, Defined Benefit [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Employer contributions	123,000,000	'	'
Expected employer contributions in 2014	103,000,000	'	'
Pension Plans, Defined Benefit [Member] | Unfunded Plans, Defined Benefit [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Employer contributions	37,000,000	'	'
Expected employer contributions in 2014	19,000,000	'	'
Other Postretirement Benefit Plans, Defined Benefit [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Employer contributions	14,000,000	19,000,000	'
Other Postretirement Benefit Plans, Defined Benefit [Member] | Unfunded Plans, Defined Benefit [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Employer contributions	14,000,000	'	'
Expected employer contributions in 2014	$15,000,000	'	'

Pension_Plans_Other_Postretire4

Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans - Change in Benefit Obligation Table (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Pension Plans, Defined Benefit [Member]	'		'		'
Change in benefit obligation	'		'		'
Benefit obligation at beginning of year	$2,297,000,000	[1]	$2,024,000,000		'
Service cost	85,000,000		76,000,000		78,000,000
Interest cost	78,000,000		85,000,000		85,000,000
Actuarial (gain) loss	-156,000,000		224,000,000		'
Participant contributions	0		1,000,000		'
Benefit payments	-149,000,000		-117,000,000		'
Foreign-currency exchange-rate changes	3,000,000		4,000,000		'
Benefit obligation at end of year (1)	2,158,000,000	[1]	2,297,000,000	[1]	2,024,000,000
Accumulated benefit obligation for all defined-benefit pension plans	1,800,000,000		2,100,000,000		'
Other Postretirement Benefit Plans, Defined Benefit [Member]	'		'		'
Change in benefit obligation	'		'		'
Benefit obligation at beginning of year	359,000,000		354,000,000		'
Service cost	9,000,000		9,000,000		9,000,000
Interest cost	14,000,000		16,000,000		16,000,000
Actuarial (gain) loss	-74,000,000		-1,000,000		'
Participant contributions	4,000,000		3,000,000		'
Benefit payments	-18,000,000		-22,000,000		'
Foreign-currency exchange-rate changes	0		0		'
Benefit obligation at end of year (1)	$294,000,000		$359,000,000		$354,000,000
[1]	The accumulated benefit obligation for all defined-benefit pension plans was $1.8 billion at December 31, 2013, and $2.1 billion at December 31, 2012.

Pension_Plans_Other_Postretire5

Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans - Change in Plan Assets, Funded Status of the Plans, and Amounts Recognized in the Financial Statements (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Pension Plans, Defined Benefit [Member]	'	'
Change in plan assets	'	'
Fair value of plan assets at beginning of year	$1,462	$1,308
Actual return on plan assets	278	159
Employer contributions	160	107
Participant contributions	0	1
Benefit payments	-149	-117
Foreign-currency exchange-rate changes	3	4
Fair value of plan assets at end of year	1,754	1,462
Funded status of the plans at end of year	-404	-835
Total recognized amounts in the balance sheet consist of	'	'
Other assets	37	30
Accrued expenses	-19	-44
Other long-term liabilities—other	-422	-821
Total	-404	-835
Total recognized amounts in accumulated other comprehensive income consist of	'	'
Prior service cost (credit)	-1	-2
Net actuarial (gain) loss	441	916
Total	440	914
Other Postretirement Benefit Plans, Defined Benefit [Member]	'	'
Change in plan assets	'	'
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	14	19
Participant contributions	4	3
Benefit payments	-18	-22
Foreign-currency exchange-rate changes	0	0
Fair value of plan assets at end of year	0	0
Funded status of the plans at end of year	-294	-359
Total recognized amounts in the balance sheet consist of	'	'
Other assets	0	0
Accrued expenses	-15	-16
Other long-term liabilities—other	-279	-343
Total	-294	-359
Total recognized amounts in accumulated other comprehensive income consist of	'	'
Prior service cost (credit)	2	3
Net actuarial (gain) loss	-78	-4
Total	($76)	($1)

Pension_Plans_Other_Postretire6

Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans - Accumulated Benefit Obligations in Excess of Plan Assets Table (Detail) (Pension Plans, Defined Benefit [Member], USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Pension Plans, Defined Benefit [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Projected benefit obligation	$2,047	$2,198
Accumulated benefit obligation	1,742	2,054
Fair value of plan assets	$1,606	$1,333

Pension_Plans_Other_Postretire7

Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans - Components of Net Periodic Benefit Cost and Amounts Recognized in Other Comprehensive Income (Expense) Table (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension Plans, Defined Benefit [Member]	'	'	'
Components of net periodic benefit cost	'	'	'
Service cost	$85	$76	$78
Interest cost	78	85	85
Expected return on plan assets	-91	-91	-85
Amortization of net actuarial loss (gain)	118	93	85
Amortization of net prior service cost (credit)	0	0	2
Settlement loss	14	0	0
Net periodic benefit cost	204	163	165
Amounts recognized in other comprehensive income (expense)	'	'	'
Net actuarial gain (loss)	342	-156	-183
Amortization of net actuarial (gain) loss	118	93	85
Net prior service (cost) credit	0	0	12
Amortization of net prior service cost (credit)	0	0	2
Settlement loss	14	0	0
Total amounts recognized in other comprehensive income (expense)	474	-63	-84
Other Postretirement Benefit Plans, Defined Benefit [Member]	'	'	'
Components of net periodic benefit cost	'	'	'
Service cost	9	9	9
Interest cost	14	16	16
Expected return on plan assets	0	0	0
Amortization of net actuarial loss (gain)	0	0	0
Amortization of net prior service cost (credit)	1	2	0
Settlement loss	0	0	0
Net periodic benefit cost	24	27	25
Amounts recognized in other comprehensive income (expense)	'	'	'
Net actuarial gain (loss)	74	1	-30
Amortization of net actuarial (gain) loss	0	0	0
Net prior service (cost) credit	0	0	0
Amortization of net prior service cost (credit)	1	2	0
Settlement loss	0	0	0
Total amounts recognized in other comprehensive income (expense)	$75	$3	($30)

Pension_Plans_Other_Postretire8

Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans - Weighted-Average Assumptions for Benefit Obligations Table (Detail)	Dec. 31, 2013	Dec. 31, 2012
Pension Plans, Defined Benefit [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Discount rate	4.75%	3.50%
Rates of increase in compensation levels	5.00%	4.50%
Other Postretirement Benefit Plans, Defined Benefit [Member]	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'
Discount rate	5.25%	4.00%
Rates of increase in compensation levels	5.25%	4.50%

Pension_Plans_Other_Postretire9

Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans - Weighted-Average Assumptions for Net Periodic Pension and Other Postretirement Benefit Cost Table (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension Plans, Defined Benefit [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Discount rate	3.50%	4.50%	4.75%
Long-term rate of return on plan assets	7.00%	7.00%	7.00%
Rates of increase in compensation levels	4.50%	4.50%	5.00%
Other Postretirement Benefit Plans, Defined Benefit [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Discount rate	4.00%	4.75%	5.25%
Rates of increase in compensation levels	4.50%	4.50%	5.00%

Recovered_Sheet1

Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans - Effects of a 1% Change in the Assumed Health Care Cost Trend Rate Table (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]	'
Effect of a 1% increase on total of service and interest cost components	$3
Effect of a 1% increase on other postretirement benefit obligation	23
Effect of a 1% decrease on total of service and interest cost components	-2
Effect of a 1% decrease on other postretirement benefit obligation	($20)

Recovered_Sheet2

Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans - Fair Value of Pension Plan Assets by Asset Category and Input Level Table (Detail) (USD $)	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
In Millions, unless otherwise specified
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Net receivables related to investments	$2		$4		'
Liabilities [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	-17		-11		'
Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	1,769	[1]	1,469	[1]	'
Fair Value, Inputs, Level 1 [Member] | Liabilities [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	-17		-11		'
Fair Value, Inputs, Level 1 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	683	[1]	508	[1]	'
Fair Value, Inputs, Level 2 [Member] | Liabilities [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	0		0		'
Fair Value, Inputs, Level 2 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	849	[1]	742	[1]	'
Fair Value, Inputs, Level 3 [Member] | Liabilities [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	0		0		'
Fair Value, Inputs, Level 3 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	237	[1]	219	[1]	191
Cash and Cash Equivalents [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	97		59		'
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	17		23		'
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	80		36		'
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	0		0		'
Mortgage-backed Securities [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	54		63		'
Mortgage-backed Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	0		0		'
Mortgage-backed Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	54		63		'
Mortgage-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	0		0		'
U.S. Government Securities [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	52		54		'
U.S. Government Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	0		0		'
U.S. Government Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	52		54		'
U.S. Government Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	0		0		'
Other Fixed-Income Securities [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	239	[2]	236	[2]	'
Other Fixed-Income Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	42	[2]	40	[2]	'
Other Fixed-Income Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	197	[2]	196	[2]	'
Other Fixed-Income Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	0	[2]	0	[2]	'
Equity Securities Domestic [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	561		422		'
Equity Securities Domestic [Member] | Fair Value, Inputs, Level 1 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	445		313		'
Equity Securities Domestic [Member] | Fair Value, Inputs, Level 2 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	116		109		'
Equity Securities Domestic [Member] | Fair Value, Inputs, Level 3 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	0		0		'
Equity Securities International [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	451		350		'
Equity Securities International [Member] | Fair Value, Inputs, Level 1 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	148		112		'
Equity Securities International [Member] | Fair Value, Inputs, Level 2 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	303		238		'
Equity Securities International [Member] | Fair Value, Inputs, Level 3 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	0		0		'
Real Estate [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	133		124		'
Real Estate [Member] | Fair Value, Inputs, Level 1 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	0		0		'
Real Estate [Member] | Fair Value, Inputs, Level 2 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	47		46		'
Real Estate [Member] | Fair Value, Inputs, Level 3 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	86		78		72
Private Equity [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	72		64		'
Private Equity [Member] | Fair Value, Inputs, Level 1 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	0		0		'
Private Equity [Member] | Fair Value, Inputs, Level 2 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	0		0		'
Private Equity [Member] | Fair Value, Inputs, Level 3 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	72		64		55
Hedge Funds and Other Alternative Strategies Asset Position [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	110		97		'
Hedge Funds and Other Alternative Strategies Asset Position [Member] | Fair Value, Inputs, Level 1 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	31		20		'
Hedge Funds and Other Alternative Strategies Asset Position [Member] | Fair Value, Inputs, Level 2 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	0		0		'
Hedge Funds and Other Alternative Strategies Asset Position [Member] | Fair Value, Inputs, Level 3 [Member] | Investments [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	79		77		64
Hedge Funds and Other Alternative Strategies Liability Position [Member] | Liabilities [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	-17		-11		'
Hedge Funds and Other Alternative Strategies Liability Position [Member] | Fair Value, Inputs, Level 1 [Member] | Liabilities [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	-17		-11		'
Hedge Funds and Other Alternative Strategies Liability Position [Member] | Fair Value, Inputs, Level 2 [Member] | Liabilities [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	0		0		'
Hedge Funds and Other Alternative Strategies Liability Position [Member] | Fair Value, Inputs, Level 3 [Member] | Liabilities [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair value of plan assets	$0		$0		'
[1]	Amount excludes net receivables of $2 million for 2013 and $4 million for 2012, primarily related to Level 1 investments.
[2]	Amounts include investments in diversified fixed-income collective investment funds with exposure to mortgage-backed securities, government-issued securities, corporate debt, and other fixed-income securities.

Recovered_Sheet3

Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans - Changes in the Fair Value of Level 3 Assets Table (Detail) (Investments [Member], USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Actual return on plan assets	'		'
Fair value of plan assets at end of year	$1,769	[1]	$1,469	[1]
Hedge Funds and Other Alternative Strategies Asset Position [Member]	'		'
Actual return on plan assets	'		'
Fair value of plan assets at end of year	110		97
Private Equity [Member]	'		'
Actual return on plan assets	'		'
Fair value of plan assets at end of year	72		64
Real Estate [Member]	'		'
Actual return on plan assets	'		'
Fair value of plan assets at end of year	133		124
Fair Value, Inputs, Level 3 [Member]	'		'
Defined Benefit Plan Disclosure [Line Items]	'		'
Fair value of plan assets at beginning of year	219	[1]	191
Acquisitions (dispositions), net	-4		15
Actual return on plan assets	'		'
Relating to assets sold during the reporting period	5		0
Relating to assets still held at the reporting date	17		13
Fair value of plan assets at end of year	237	[1]	219	[1]
Fair Value, Inputs, Level 3 [Member] | Hedge Funds and Other Alternative Strategies Asset Position [Member]	'		'
Defined Benefit Plan Disclosure [Line Items]	'		'
Fair value of plan assets at beginning of year	77		64
Acquisitions (dispositions), net	-6		9
Actual return on plan assets	'		'
Relating to assets sold during the reporting period	1		-2
Relating to assets still held at the reporting date	7		6
Fair value of plan assets at end of year	79		77
Fair Value, Inputs, Level 3 [Member] | Private Equity [Member]	'		'
Defined Benefit Plan Disclosure [Line Items]	'		'
Fair value of plan assets at beginning of year	64		55
Acquisitions (dispositions), net	0		4
Actual return on plan assets	'		'
Relating to assets sold during the reporting period	4		2
Relating to assets still held at the reporting date	4		3
Fair value of plan assets at end of year	72		64
Fair Value, Inputs, Level 3 [Member] | Real Estate [Member]	'		'
Defined Benefit Plan Disclosure [Line Items]	'		'
Fair value of plan assets at beginning of year	78		72
Acquisitions (dispositions), net	2		2
Actual return on plan assets	'		'
Relating to assets sold during the reporting period	0		0
Relating to assets still held at the reporting date	6		4
Fair value of plan assets at end of year	$86		$78
[1]	Amount excludes net receivables of $2 million for 2013 and $4 million for 2012, primarily related to Level 1 investments.

Recovered_Sheet4

Pension Plans, Other Postretirement Benefits, and Defined-Contribution Plans - Expected Benefit Payments Table (Detail) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Pension Plans, Defined Benefit [Member]	'
Defined Benefit Plan Disclosure [Line Items]	'
2014	$139
2015	148
2016	163
2017	185
2018	181
2019-2023	1,065
Other Postretirement Benefit Plans, Defined Benefit [Member]	'
Defined Benefit Plan Disclosure [Line Items]	'
2014	15
2015	16
2016	16
2017	17
2018	18
2019-2023	$98