Transactions with Affiliates - Summary of Affiliate Transactions Table (Details) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015		Jun. 30, 2016		Jun. 30, 2015
Related Party Transaction [Line Items]
Revenues and other		$ 428,664	$ 465,993	[1]	$ 811,805		$ 902,999	[1]
Equity income, net – affiliates	[2]	19,693	18,941	[1]	36,507		37,161	[1]
Cost of product	[3]	104,849	147,216	[1]	181,316		286,624	[1]
Operation and maintenance	[3]	75,173	77,837	[1]	151,386		154,022	[1]
General and administrative	[3]	11,887	10,183	[1]	24,402		22,099	[1]
Operating expenses		273,710	315,022	[1]	520,868		893,410	[1]
Interest income	[4]	4,225	4,225	[1]	8,450		8,450	[1]
Interest expense	[5]	13,429	27,604	[1]	45,568		50,566	[1]
Distributions to unitholders	[6]				181,156		143,386	[1]
Above-market component of swap extensions with Anadarko		9,552	0		16,365	[6]	0	[1],[6]
Affiliates [Member]
Related Party Transaction [Line Items]
Revenues and other	[2]	302,405	321,411	[1]	574,989		628,339	[1]
Cost of product	[2]	22,145	53,062		46,725		96,957
Operation and maintenance	[7]	17,661	19,854		35,636		36,671
General and administrative	[8]	9,374	8,254		18,524		16,589
Operating expenses		49,180	81,170		100,885		150,217
Interest expense	[9]	(15,461)	4,190		(10,924)		5,612
Affiliates [Member] | Western Gas Partners, LP [Member]
Related Party Transaction [Line Items]
Distributions to unitholders	[10]	1,639	550		2,245		1,080
Affiliates [Member] | Western Gas Equity Partners, LP [Member]
Related Party Transaction [Line Items]
Distributions to unitholders	[11]	$ 80,973	$ 66,235		$ 158,125		$ 126,669

[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 $22.1 million and $46.7 million for the three and six months ended June 30, 2016, respectively, and $53.1 million and $97.0 million for the three and six months ended June 30, 2015, respectively. Operation and maintenance includes charges from Anadarko of $17.7 million and $35.6 million for the three and six months ended June 30, 2016, respectively, and $19.9 million and $36.7 million for the three and six months ended June 30, 2015, respectively. General and administrative includes charges from Anadarko of $9.4 million and $18.5 million for the three and six months ended June 30, 2016, respectively, and $8.3 million and $16.6 million for the three and six months ended June 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 $(15.5) million and $(10.9) million for the three and six months ended June 30, 2016, respectively, and $4.2 million and $5.6 million for the three and six months ended June 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 six months ended June 30, 2016, includes WES’s accretion revisions to the Deferred purchase price obligation - Anadarko (see Note 2 and Note 9) and for the three and six months ended June 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).