Percentage of convertible preferred unit that will be converted to common units on a designated date.

No definition available.

Name:	apc_ConvertiblePreferredUnitsPercentageConversion
Namespace Prefix:	apc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Original sales price before closing adjustments related to the sale of midstream assets.

+ References

No definition available.

+ Details

Name:	apc_MidstreamAssetsOriginalSalesPrice
Namespace Prefix:	apc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number of tangible equity units issued during the period.

+ References

No definition available.

+ Details

Name:	apc_TangibleEquityUnitsNumberOfUnitsIssued
Namespace Prefix:	apc_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of units sold in a private placement of each class of partners' capital account. Units represent shares of ownership of the general, limited, and preferred partners.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 5
-Subparagraph (SAB Topic 4.F)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187171-122770

+ Details

Name:	us-gaap_PartnersCapitalAccountUnitsSoldInPrivatePlacement
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of units sold in a public offering of each class of partners' capital account. Units represent shares of ownership of the general, limited, and preferred partners.

+ References

+ Details

Name:	us-gaap_PartnersCapitalAccountUnitsSoldInPublicOffering
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash inflow from the issuance of common limited partners units during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3255-108585

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfCommonLimitedPartnersUnits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash inflow associated with the amount received from entity's raising of capital via private rather than public placement.

+ References

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfPrivatePlacement
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash inflow to dispose of long-lived, physical assets and mineral interests in oil and gas properties used for normal oil and gas operations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3179-108585

+ Details

Name:	us-gaap_ProceedsFromSaleOfOilAndGasPropertyAndEquipment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Number of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

+ Details

Name:	us-gaap_SharesIssued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=apc_TangibleEquityUnits1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=apc_WesternGasPartnersLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PartnerTypeOfPartnersCapitalAccountAxis=us-gaap_LimitedPartnerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=apc_WesternGasEquityPartnersLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=apc_ConvertiblePreferredUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=apc_ClassCUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=apc_AnadarkoLimitedPartnerInterestInWESMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=apc_AnadarkoLimitedPartnerInterestInWESOwnedThroughOtherSubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=apc_WesternGasEquityPartnersLPOwnershipInterestinWesternGasPartnersLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PartnerTypeOfPartnersCapitalAccountAxis=us-gaap_GeneralPartnerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	apc_SettlementScenarioAxis=apc_SettledInWgpCommonUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=apc_EquityComponentOfTangibleEquityUnits1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Noncontrolling Interests (Detail) - USD ($) shares in Thousands, $ in Millions		1 Months Ended	3 Months Ended	12 Months Ended
	Mar. 01, 2017	Jun. 30, 2015	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jun. 07, 2018
Scenario, Forecast [Member]
Noncontrolling Interest [Line Items]
Sale of assets, consideration			$ 4,000
Cash proceeds from sale of assets			$ 2,000
7.50% Tangible Equity Units [Member]
Noncontrolling Interest [Line Items]
Number of tangible equity units issued (in units)		9,200
Western Gas Partners LP [Member]
Noncontrolling Interest [Line Items]
Units issued in private placement					1,300
Western Gas Partners LP [Member] \| Limited Partner [Member]
Noncontrolling Interest [Line Items]
Public ownership interest in subsidiary				59.20%
Western Gas Partners LP [Member] \| Limited Partner [Member] \| Scenario, Forecast [Member]
Noncontrolling Interest [Line Items]
Ownership interest in subsidiary			55.50%
Western Gas Equity Partners LP [Member]
Noncontrolling Interest [Line Items]
Units issued to the public					12,500
Net proceeds raised from public offering					$ 476
Western Gas Equity Partners LP [Member] \| Limited Partner [Member]
Noncontrolling Interest [Line Items]
Ownership interest in subsidiary				77.80%
Public ownership interest in subsidiary				22.20%
Convertible Preferred Units [Member] \| Western Gas Partners LP [Member]
Noncontrolling Interest [Line Items]
Units issued in private placement					22,000
Percentage of preferred units converted	50.00%
Proceeds from issuance of private placement					$ 687
Class C Units [Member] \| Western Gas Partners LP [Member]
Noncontrolling Interest [Line Items]
Units issued in private placement				1,100	886	946
WES LP [Member] \| Western Gas Partners LP [Member] \| Limited Partner [Member] \| Scenario, Forecast [Member]
Noncontrolling Interest [Line Items]
Ownership interest in subsidiary			2.00%
Anadarko Limited Partner Interest In WES Owned Through Other Subsidiaries [Member] \| Western Gas Partners LP [Member] \| Limited Partner [Member]
Noncontrolling Interest [Line Items]
Ownership interest in subsidiary				9.70%
Western Gas Equity Partners, LP Ownership Interest in Western Gas Partners, LP [Member] \| Western Gas Partners LP [Member] \| Limited Partner [Member]
Noncontrolling Interest [Line Items]
Ownership interest in subsidiary				29.60%
Western Gas Equity Partners, LP Ownership Interest in Western Gas Partners, LP [Member] \| Western Gas Partners LP [Member] \| Limited Partner [Member] \| Scenario, Forecast [Member]
Noncontrolling Interest [Line Items]
Ownership interest in subsidiary			98.00%
Western Gas Equity Partners, LP Ownership Interest in Western Gas Partners, LP [Member] \| Western Gas Partners LP [Member] \| General Partner [Member]
Noncontrolling Interest [Line Items]
Ownership interest in subsidiary				1.50%
Settled In Wgp Common Units [Member] \| Equity Component of 7.5% Tangible Equity Units [Member]
Noncontrolling Interest [Line Items]
Shares issued (in shares)							8,200