Number of tangible equity units issued during the period.

No definition available.

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://www.xbrl.org/2003/role/presentationRef

-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

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 16

-Subparagraph a, b

-Article 6

+ 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://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3255-108585

+ Details

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

- Details

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

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis=apc_Partnership1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis=us-gaap_PartnershipMember
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:	invest_InvestmentAxis=apc_ContinuousOfferingProgramMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=us-gaap_PartnershipInterestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=apc_PartnershipInterest1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

Noncontrolling Interests (Detail) - USD ($) shares in Thousands, $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
7.50% Tangible Equity Units [Member]
Noncontrolling Interest [Line Items]
Net proceeds	$ 348	$ 0
Number of tangible equity units issued	9,200
Western Gas Equity Partners, LP [Member]
Noncontrolling Interest [Line Items]
Units issued to the public	2,300
Net proceeds	$ 130
Western Gas Equity Partners, LP [Member] \| Limited Partner [Member]
Noncontrolling Interest [Line Items]
Ownership interest in subsidiary	87.30%
Public ownership interest in subsidiary	12.70%
Western Gas Partners, LP [Member] \| Class C Units [Member]
Noncontrolling Interest [Line Items]
Units issued in private placement	317		11,000
Western Gas Partners, LP [Member] \| Continuous Offering Program [Member]
Noncontrolling Interest [Line Items]
Units issued to the public	874
Net proceeds	$ 57
Western Gas Partners, LP [Member] \| Limited Partner [Member]
Noncontrolling Interest [Line Items]
Public ownership interest in subsidiary	55.20%
Western Gas Partners, LP [Member] \| Limited Partner [Member] \| Western Gas Equity Partners, LP, Ownership Interest [Member]
Noncontrolling Interest [Line Items]
Ownership interest in subsidiary	34.60%
Western Gas Partners, LP [Member] \| Limited Partner [Member] \| Other Anadarko Subsidiaries, Ownership Interest [Member]
Noncontrolling Interest [Line Items]
Ownership interest in subsidiary	8.40%
Western Gas Partners, LP [Member] \| General Partner [Member] \| Western Gas Equity Partners, LP, Ownership Interest [Member]
Noncontrolling Interest [Line Items]
Ownership interest in subsidiary	1.80%