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Description of Business and Basis of Presentation - Additional Information (details) (Western Gas Partners [Member])
 1 Months Ended 3 Months Ended 0 Months Ended
Nov. 30, 2014
Mar. 31, 2015
Mar. 02, 2015
General partner's interest 2.00%us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest 1.80%us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest  
Marginal percentage interest in distributions   48.00%wgp_DistributionPercentageMadeToGeneralPartner  
Other Subsidiaries Of Anadarko [Member]
      
Units issued   757,619us-gaap_PartnersCapitalAccountUnitsAcquisitions
/ dei_LegalEntityAxis
= wgp_WesternGasPartnersMember
/ us-gaap_OtherOwnershipInterestsByNameAxis
= wgp_OtherSubsidiariesOfAnadarkoMember		  
Non-Operated Marcellus Interest [Member]
      
Ownership interest   33.75%us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest
/ us-gaap_BusinessAcquisitionAxis
= wgp_NonOperatedMarcellusInterestMember
/ dei_LegalEntityAxis
= wgp_WesternGasPartnersMember		  
Anadarko-Operated Marcellus Interest [Member]
      
Ownership interest   33.75%us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest
/ us-gaap_BusinessAcquisitionAxis
= wgp_AnadarkoOperatedMarcellusInterestMember
/ dei_LegalEntityAxis
= wgp_WesternGasPartnersMember		  
Delaware Basin JV Gathering LLC [Member]
      
Ownership interest   50.00%us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest
/ us-gaap_BusinessAcquisitionAxis
= wgp_DelawareBasinJointVentureGatheringLimitedLiabilityCompanyMember
/ dei_LegalEntityAxis
= wgp_WesternGasPartnersMember		 50.00%us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest
/ us-gaap_BusinessAcquisitionAxis
= wgp_DelawareBasinJointVentureGatheringLimitedLiabilityCompanyMember
/ dei_LegalEntityAxis
= wgp_WesternGasPartnersMember		 [1]
Newcastle [Member]
      
Ownership interest   50.00%us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest
/ us-gaap_BusinessAcquisitionAxis
= wgp_NewcastleMember
/ dei_LegalEntityAxis
= wgp_WesternGasPartnersMember		  
Fort Union [Member]
      
Equity investment ownership   14.81%us-gaap_EquityMethodInvestmentOwnershipPercentage
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= wgp_WesternGasPartnersMember
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Rendezvous [Member]
      
Equity investment ownership   22.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ dei_LegalEntityAxis
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White Cliffs [Member]
      
Equity investment ownership   10.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ dei_LegalEntityAxis
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= wgp_WhiteCliffsMember		  
Mont Belvieu Joint Venture [Member]
      
Equity investment ownership   25.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ dei_LegalEntityAxis
= wgp_WesternGasPartnersMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= wgp_MontBelvieuJointVentureMember		  
Texas Express Pipeline Limited Liability Company [Member]
      
Equity investment ownership   20.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ dei_LegalEntityAxis
= wgp_WesternGasPartnersMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= wgp_TexasExpressPipelineLimitedLiabilityCompanyMember		  
Texas Express Gathering Limited Liability Company [Member]
      
Equity investment ownership   20.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ dei_LegalEntityAxis
= wgp_WesternGasPartnersMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= wgp_TexasExpressGatheringLimitedLiabilityCompanyMember		  
Front Range Pipeline Limited Liability Company [Member]
      
Equity investment ownership   33.33%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ dei_LegalEntityAxis
= wgp_WesternGasPartnersMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= wgp_FrontRangePipelineLimitedLiabilityCompanyMember		  
Incentive Distribution Rights [Member]      
General partner's interest   100.00%us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest
/ us-gaap_CapitalUnitsByClassAxis
= wgp_IncentiveDistributionRightsMember
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= wgp_WesternGasPartnersMember		  
General Partner [Member]      
Ownership interest   100.00%us-gaap_SubsidiaryOfLimitedLiabilityCompanyOrLimitedPartnershipOwnershipInterest
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= us-gaap_GeneralPartnerMember
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[1] WES acquired Anadarko’s interest in Delaware Basin JV Gathering LLC (“DBJV”), which owns a 50% interest in a gathering system and related facilities (the “DBJV system”). The DBJV system is located in the Delaware Basin in Loving, Ward, Winkler and Reeves Counties, Texas. WES will make a cash payment on March 31, 2020, to Anadarko as consideration for the acquisition of DBJV. WES currently estimates the future payment will be $282.8 million, the net present value of which was $174.3 million as of the acquisition date. See Deferred purchase price obligation - Anadarko below.