Acquisitions and Divestitures - Acquisitions Table (Details) - USD ($) $ in Thousands							12 Months Ended
		Mar. 17, 2017		Mar. 14, 2016	Mar. 02, 2015		Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Business Acquisition [Line Items]
Deferred purchase price obligation - Anadarko, present value	[1]						$ 0		$ 41,440
Affiliates [Member]
Business Acquisition [Line Items]
Cash on hand							$ 3,910		716,465		$ 10,903
Revolving Credit Facility [Member] | WGP RCF [Member]
Business Acquisition [Line Items]
Borrowings - revolving credit facility				$ 25,000					$ 28,000
Western Gas Partners, LP [Member]
Business Acquisition [Line Items]
WES units issued							885,760		946,261
Western Gas Partners, LP [Member] | Revolving Credit Facility [Member] | WES RCF [Member]
Business Acquisition [Line Items]
Borrowings - revolving credit facility							$ 370,000		$ 600,000
Western Gas Partners, LP [Member] | Delaware Basin JV Gathering LLC [Member]
Business Acquisition [Line Items]
Ownership percentage acquired		50.00%	[2]		50.00%	[3]
Cash on hand	[2]	$ 155,000
Western Gas Partners, LP [Member] | Delaware Basin JV Gathering LLC [Member] | Deferred Purchase Price Obligation - Anadarko [Member] | Affiliates [Member]
Business Acquisition [Line Items]
Deferred purchase price obligation - Anadarko, future value					$ 282,800		0	[4]	56,455	[4]	282,807	[4]
Deferred purchase price obligation - Anadarko, present value					$ 174,300		$ 0		$ 41,440		$ 188,674
Western Gas Partners, LP [Member] | Springfield [Member]
Business Acquisition [Line Items]
Ownership percentage acquired	[5]			50.10%
Acquisition price				$ 750,000
Cash payment for acquisition				$ 712,500
Western Gas Partners, LP [Member] | Springfield [Member] | Common Units [Member]
Business Acquisition [Line Items]
WES units issued	[5]			2,089,602
Western Gas Partners, LP [Member] | Springfield [Member] | Common Units [Member] | Anadarko [Member]
Business Acquisition [Line Items]
WES units issued				1,253,761
Western Gas Partners, LP [Member] | Springfield [Member] | Common Units [Member] | Western Gas Equity Partners, LP [Member]
Business Acquisition [Line Items]
WES units issued				835,841
Western Gas Partners, LP [Member] | Springfield [Member] | Series A Preferred Units [Member]
Business Acquisition [Line Items]
WES units issued	[5]			14,030,611
Western Gas Partners, LP [Member] | Springfield [Member] | Revolving Credit Facility [Member] | WES RCF [Member]
Business Acquisition [Line Items]
Borrowings - revolving credit facility	[5]			$ 247,500

[1] See Note 2.

[2] WES acquired the Additional DBJV System Interest from a third party. See Property exchange below.

[3] WES acquired Delaware Basin JV Gathering LLC (“DBJV”) from Anadarko. At the time of acquisition, DBJV owned a 50% interest in a gathering system and related facilities (the “DBJV system”) located in the Delaware Basin in Loving, Ward, Winkler and Reeves Counties, Texas. At the acquisition date, WES estimated the future payment would be $282.8 million, the estimated net present value of which was $174.3 million. For further information, see DBJV acquisition—deferred purchase price obligation - Anadarko below.

[4] Calculated using Level 3 inputs.

[5] WES acquired Springfield Pipeline LLC (“Springfield”) from Anadarko for $750.0 million, consisting of $712.5 million in cash and the issuance of 1,253,761 of WES common units. Springfield owns a 50.1% interest in an oil gathering system and a gas gathering system. The Springfield oil and gas gathering systems (collectively, the “Springfield system”) are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. WES financed the cash portion of the acquisition through: (i) borrowings of $247.5 million on the WES RCF, (ii) the issuance of 835,841 of WES common units to WGP and (iii) the issuance of WES Series A Preferred units to private investors. See Note 4 for further information regarding WES’s Series A Preferred units. WGP financed the purchase of the WES common units by borrowing $25.0 million under the WGP RCF. See Note 12.