Transactions with Affiliates - Summary of Affiliate Transactions Table (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015		Sep. 30, 2016		Sep. 30, 2015
Related Party Transaction [Line Items]
Revenues and other		$ 481,645	$ 432,515	[1]	$ 1,293,450		$ 1,335,514	[1]
Equity income, net – affiliates	[2]	20,294	21,976	[1]	56,801		59,137	[1]
Cost of product	[3]	145,643	127,704	[1]	326,959		414,328	[1]
Operation and maintenance	[3]	74,755	88,722	[1]	226,141		242,744	[1]
General and administrative	[3]	12,112	10,884	[1]	36,514		32,983	[1]
Operating expenses		312,818	306,066	[1]	833,686		1,199,476	[1]
Interest income	[4]	4,225	4,225	[1]	12,675		12,675	[1]
Interest expense	[5]	31,301	31,773	[1]	76,869		82,339	[1]
Distributions to unitholders	[6]				276,114		223,016	[1]
Above-market component of swap extensions with Anadarko		18,417	7,916		34,782	[6]	7,916	[1],[6]
Affiliates [Member]
Related Party Transaction [Line Items]
Revenues and other	[2]	325,312	294,849	[1]	900,301		923,188	[1]
Cost of product	[2]	21,254	35,656		67,979		132,613
Operation and maintenance	[7]	15,052	19,394		50,688		56,065
General and administrative	[8]	9,655	8,700		28,179		25,289
Operating expenses		45,961	63,750		146,846		213,967
Interest expense	[9]	(1,173)	4,310		(12,097)		9,922
Affiliates [Member] | Western Gas Partners, LP [Member]
Related Party Transaction [Line Items]
Distributions to unitholders	[10]	1,670	568		3,915		1,648
Affiliates [Member] | Western Gas Equity Partners, LP [Member]
Related Party Transaction [Line Items]
Distributions to unitholders	[11]	$ 77,462	$ 69,508		$ 235,587		$ 196,177

[1] Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.

[2] Represents amounts earned or incurred on and subsequent to the date of acquisition of WES assets, as well as amounts earned or incurred by Anadarko on a historical basis related to WES assets prior to the acquisition of such assets by WES, recognized under gathering, treating or processing agreements, and purchase and sale agreements.

[3] Cost of product includes product purchases from Anadarko (as defined in Note 1) of $21.3 million and $68.0 million for the three and nine months ended September 30, 2016, respectively, and $35.7 million and $132.6 million for the three and nine months ended September 30, 2015, respectively. Operation and maintenance includes charges from Anadarko of $15.1 million and $50.7 million for the three and nine months ended September 30, 2016, respectively, and $19.4 million and $56.1 million for the three and nine months ended September 30, 2015, respectively. General and administrative includes charges from Anadarko of $9.7 million and $28.2 million for the three and nine months ended September 30, 2016, respectively, and $8.7 million and $25.3 million for the three and nine months ended September 30, 2015, respectively. See Note 5.

[4] Represents interest income recognized on the note receivable from Anadarko.

[5] Includes affiliate (as defined in Note 1) amounts of $1.2 million and $12.1 million for the three and nine months ended September 30, 2016, respectively, and $(4.3) million and $(9.9) million for the three and nine months ended September 30, 2015, respectively. See Note 2 and Note 9.

[6] See Note 5.

[7] Represents expenses incurred on and subsequent to the date of the acquisition of WES assets, as well as expenses incurred by Anadarko on a historical basis related to WES assets prior to the acquisition of such assets by WES.

[8] Represents general and administrative expense incurred on and subsequent to the date of WES’s acquisition of WES assets, as well as a management services fee for reimbursement of expenses incurred by Anadarko for periods prior to the acquisition of WES assets by WES. These amounts include equity-based compensation expense allocated to WES and WGP by Anadarko (see WES LTIP and WGP LTIP and Anadarko Incentive Plans within this Note 5) and amounts charged by Anadarko under the WGP omnibus agreement.

[9] For the three and nine months ended September 30, 2016, includes WES’s accretion revisions to the Deferred purchase price obligation - Anadarko (see Note 2 and Note 9) and for the nine months ended September 30, 2015, includes interest expense recognized on the WGP WCF (see Note 9).

[10] Represents distributions paid to other subsidiaries of Anadarko under WES’s partnership agreement (see Note 3 and Note 4).

[11] Represents distributions paid under WGP’s partnership agreement (see Note 3 and Note 4).