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Commitments and Contingencies - Additional Information (details) (Western Gas Partners [Member], USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Western Gas Partners [Member]
   
Loss Contingencies [Line Items]    
Committed capital $ 24.1us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnFirstAnniversary
/ dei_LegalEntityAxis
= wgp_WesternGasPartnersMember
 
Rent expense associated with office, warehouse and equipment leases $ 4.2us-gaap_LeaseAndRentalExpense
/ dei_LegalEntityAxis
= wgp_WesternGasPartnersMember
$ 2.3us-gaap_LeaseAndRentalExpense
/ dei_LegalEntityAxis
= wgp_WesternGasPartnersMember