Disclosure of the difference in values (gain (loss)) between the nonmonetary assets or liabilities exchanged with another entity inclusive of boot (small monetary consideration).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 845
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=68069686&loc=d3e32049-108421

+ Details

Name:	us-gaap_NonmonetaryTransactionGainLossRecognizedOnTransfer
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of cash outflow, not made soon after acquisition date of business combination, to settle contingent consideration liability up to amount recognized at acquisition date, including, but not limited to, measurement period adjustment and less amount paid soon after acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

+ Details

Name:	us-gaap_PaymentForContingentConsiderationLiabilityFinancingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash outflow for purchases of and capital improvements on property, plant and equipment (capital expenditures), software, and other intangible assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireProductiveAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_PropertyPlantAndEquipmentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of units or percentage investment held in the subsidiary by the limited liability company or limited partnership.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=50485924&loc=d3e611443-123010

+ Details

Name:	us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Ownership interest purchased.

+ References

No definition available.

+ Details

Name:	wgp_OwnershipInterestPurchased
Namespace Prefix:	wgp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Details

Name:	us-gaap_BusinessAcquisitionAxis=wgp_DelawareBasinJointVentureGatheringLimitedLiabilityCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherCommitmentsAxis=wgp_DeferredPurchasePriceObligationToAnadarkoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_NonmonetaryTransactionTypeAxis=wgp_NonOperatedMarcellusInterestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Acquisitions and Divestitures - Additional Information (Details) - Western Gas Partners, LP [Member] - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
	Mar. 17, 2017	Mar. 31, 2017	Jun. 30, 2017
Delaware Basin JV Gathering LLC [Member]
Property, Plant and Equipment [Line Items]
Ownership percentage acquired	50.00%
Percentage ownership interest	50.00%
Cash payment	$ 155,000
Net gain from property exchange		$ 125,700
Delaware Basin JV Gathering LLC [Member] \| Deferred Purchase Price Obligation - Anadarko [Member] \| Affiliates [Member]
Property, Plant and Equipment [Line Items]
Settlement of the Deferred purchase price obligation - Anadarko			$ 37,346
Non-Operated Marcellus Interest [Member]
Property, Plant and Equipment [Line Items]
Percentage ownership interest	33.75%