Summary of Significant Accounting Policies - Additional Information (details) (USD $)	1 Months Ended			12 Months Ended		0 Months Ended				1 Months Ended	0 Months Ended		1 Months Ended
	Dec. 31, 2012	Nov. 30, 2014		Dec. 31, 2014		Mar. 01, 2013		Mar. 08, 2013		Dec. 31, 2008	Aug. 01, 2012		Jul. 31, 2009	Dec. 31, 2013		May 31, 2013		Jun. 30, 2012	Nov. 25, 2014
Common units issued				218,909,977										218,895,515
Natural gas imbalance receivables				$ 415,000										$ 3,605,000
Natural gas imbalance payables				700,000										2,500,000
Western Gas Equity Partners Long Term Incentive Plan [Member]
Units authorized under LTIP				3,000,000
Units available under LTIP				2,959,364
IPO [Member]
Common units issued	19,758,150
Price per unit	$ 22.00
Proceeds from issuance of initial public offering	412,000,000
Payment for purchase of private placement	$ 409,400,000
Western Gas Partners [Member]
General partner's interest		2.00%		1.80%
Marginal percentage interest in distributions				48.00%
Price per unit		$ 70.85	[1]											$ 61.51	[2]	$ 61.18	[3]	$ 43.88
Ownership interest				100.00%
Western Gas Partners [Member] | Western Gas Partners Long Term Incentive Plan [Member]
Units authorized under LTIP				2,250,000
Units available under LTIP				2,133,227
Western Gas Partners [Member] | Other Subsidiaries Of Anadarko [Member]
Units issued				757,619
Western Gas Partners [Member] | Incentive Distribution Rights [Member]
General partner's interest				100.00%
Western Gas Partners [Member] | Class C Units [Member]
Price per unit																			$ 68.72
Class C units issued				10,913,853
Western Gas Partners [Member] | Class C Units [Member] | Other Subsidiaries Of Anadarko [Member]
Class C units issued		10,913,853		10,913,853	[4]
Western Gas Partners [Member] | Non-Operated Marcellus Interest [Member]
Ownership interest				33.75%		33.75%	[5]
Western Gas Partners [Member] | Anadarko-Operated Marcellus Interest [Member]
Ownership interest				33.75%				33.75%	[6]
Western Gas Partners [Member] | Newcastle [Member]
Ownership interest				50.00%						50.00%
Western Gas Partners [Member] | Chipeta Processing Limited Liability Company [Member]
Ownership interest				75.00%							24.00%	[7]	51.00%
Ownership interest by noncontrolling owner				25.00%
Western Gas Partners [Member] | Fort Union [Member]
Equity investment ownership				14.81%
Western Gas Partners [Member] | Rendezvous [Member]
Equity investment ownership				22.00%
Western Gas Partners [Member] | White Cliffs [Member]
Equity investment ownership				10.00%
Western Gas Partners [Member] | Mont Belvieu Joint Venture [Member]
Equity investment ownership				25.00%
Western Gas Partners [Member] | Texas Express Pipeline Limited Liability Company [Member]
Equity investment ownership				20.00%
Western Gas Partners [Member] | Texas Express Gathering Limited Liability Company [Member]
Equity investment ownership				20.00%
Western Gas Partners [Member] | Front Range Pipeline Limited Liability Company [Member]
Equity investment ownership				33.33%

[1] Includes the issuance of 1,120,153 WES common units pursuant to the partial exercise of the underwriters’ over-allotment option. Net proceeds from this partial exercise were $77.0 million. Beginning with this partial exercise, WES WGP elected not to make a corresponding capital contribution to maintain the 2.0% general partner interest in WES. See Note 3.

[2] Includes the issuance of 300,000 WES common units on January 3, 2014, pursuant to the partial exercise of the underwriters’ over-allotment option. Net proceeds from this partial exercise (including WES GP’s proportionate capital contribution) were $18.1 million.

[3] Includes the issuance of 915,000 WES common units pursuant to the full exercise of the underwriters’ over-allotment option.

[4] WES acquired Nuevo Midstream, LLC (“Nuevo”) from a third party. Following the acquisition, WES changed the name of Nuevo to Delaware Basin Midstream, LLC (“DBM”). The assets acquired include cryogenic processing plants, a gas gathering system, and related facilities and equipment, which serve production from Reeves, Loving and Culberson Counties, Texas and Eddy and Lea Counties, New Mexico. These assets are referred to collectively as the “DBM complex.” See Note 4 for a discussion of the WES Class C units.

[5] WES acquired Anadarko’s 33.75% interest (non-operated) (the “Non-Operated Marcellus Interest”) in the Liberty and Rome gas gathering systems (the “Non-Operated Marcellus Interest systems”), serving production from the Marcellus shale in North-central Pennsylvania. In connection with the issuance of WES common units, WES GP purchased 9,166 general partner units for consideration of $0.5 million.

[6] WES acquired a 33.75% interest (the “Anadarko-Operated Marcellus Interest”) in each of the Larry’s Creek, Seely and Warrensville gas gathering systems (the “Anadarko-Operated Marcellus Interest systems”), which are operated by Anadarko and serve production from the Marcellus shale in North-central Pennsylvania, from a third party. During the third quarter of 2013, WES recorded a $1.1 million decrease in the assets acquired and liabilities assumed in the acquisition, representing the final purchase price allocation.

[7] WES acquired Anadarko’s additional Chipeta interest (as described in Note 1). WES received distributions related to the additional interest beginning July 1, 2012. This transaction brought WES’s total membership interest in Chipeta to 75%. The remaining 25% membership interest in Chipeta held by a third-party member is reflected as noncontrolling interests in the consolidated financial statements for all periods presented.