Equity and Partners' Capital - Limited Partner and General Partner Units Table (details) - Western Gas Partners [Member] - shares		1 Months Ended	3 Months Ended
		Nov. 30, 2014	Mar. 31, 2015
Capital Unit [Line Items]
Balance			141,192,051
PIK Class C units			45,711
Long-Term Incentive Plan award vestings			2,014
Balance			141,719,885
500 Million COP [Member]
Capital Unit [Line Items]
Offering			480,109
Common Units [Member]
Capital Unit [Line Items]
Balance			127,695,130
Long-Term Incentive Plan award vestings			2,014
Offering	[1]	8,620,153
Balance			128,177,253
Common Units [Member] | 500 Million COP [Member]
Capital Unit [Line Items]
Offering	[2]		480,109
Class C Units [Member]
Capital Unit [Line Items]
Balance			10,913,853
PIK Class C units			45,711
Balance			10,959,564
General Partner [Member]
Capital Unit [Line Items]
Balance			2,583,068
PIK Class C units	[1],[3]	153,061
Balance			2,583,068

[1] Includes the issuance of 1,120,153 WES common units pursuant to the partial exercise of the underwriters’ over-allotment option, the net proceeds from which were $77.0 million. Beginning with this partial exercise, WES GP elected not to make a corresponding capital contribution to maintain its 2.0% interest in WES.

[2] Represents common units of WES issued during the three months ended March 31, 2015, pursuant to WES’s registration statement filed with the SEC in August 2014 authorizing the issuance of up to an aggregate of $500.0 million of WES common units (the “$500.0 million COP”). Gross proceeds generated and commissions paid during the three months ended March 31, 2015, were $31.5 million and $0.3 million, respectively. The price per unit in the table above represents an average price for all issuances under the $500.0 million COP during the three months ended March 31, 2015. Does not include sales of 289,744 WES common units that settled after March 31, 2015.

[3] Represents general partner units of WES issued to WES GP in exchange for WES GP’s proportionate capital contribution.