Equity and Partners' Capital - Equity Offerings Table (Details) - Western Gas Partners, LP [Member] - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
		Nov. 30, 2014	Sep. 30, 2015	Sep. 30, 2015	Dec. 31, 2014	Aug. 31, 2014	Aug. 31, 2012
Capital Unit [Line Items]
Units issued				316,961
Price per unit	[1]	$ 70.85
Underwriting discount and other offering expenses	[1]	$ 18,615
Net proceeds to WES	[1]	$ 602,967
Table Text Block Supplement [Abstract]
General partner's interest		2.00%		1.80%
Option on Securities [Member]
Capital Unit [Line Items]
Net proceeds to WES		$ 77,000
125 Million COP [Member]
Capital Unit [Line Items]
Average price per unit	[2]				$ 73.48
Underwriting discount and other offering expenses	[2]				$ 1,738
Net proceeds to WES	[2]				83,245
Table Text Block Supplement [Abstract]
Maximum aggregate principal of common units							$ 125,000
Gross proceeds					$ 85,000
500 Million COP [Member]
Capital Unit [Line Items]
Common units issued				873,525
Average price per unit	[3]			$ 66.61
Underwriting discount and other offering expenses	[3]		$ 805	$ 805
Net proceeds to WES	[3]			57,385
Table Text Block Supplement [Abstract]
Maximum aggregate principal of common units						$ 500,000
Gross proceeds			0	58,200
Commissions paid			$ 0	$ 600
Common Units [Member]
Capital Unit [Line Items]
Common units issued	[1]	8,620,153
Common Units [Member] | Option on Securities [Member]
Capital Unit [Line Items]
Common units issued		1,120,153
Common Units [Member] | 125 Million COP [Member]
Capital Unit [Line Items]
Common units issued	[2]				1,133,384
Common Units [Member] | 500 Million COP [Member]
Capital Unit [Line Items]
Common units issued	[3]			873,525
General Partner [Member]
Capital Unit [Line Items]
Units issued	[1],[4]	153,061
General Partner [Member] | 125 Million COP [Member]
Capital Unit [Line Items]
Units issued	[2],[4]				23,132

[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 and general partner units of WES issued during the year ended December 31, 2014, pursuant to WES’s registration statement filed with the SEC in August 2012 authorizing the issuance of up to an aggregate of $125.0 million of WES common units (the “$125.0 million COP”). Gross proceeds generated (including WES GP’s proportionate capital contributions) during the year ended December 31, 2014, were $85.0 million. The price per unit in the table above represents an average price for all issuances under the $125.0 million COP during the year ended December 31, 2014. As of December 31, 2014, WES had used all the capacity to issue common units under this registration statement.

[3] Represents common units of WES issued during the nine months ended September 30, 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 during the three and nine months ended September 30, 2015, were zero and $58.2 million, respectively. Commissions paid during the three and nine months ended September 30, 2015, were zero and $0.6 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 nine months ended September 30, 2015.

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