Transactions with Affiliates - Summary of Affiliate Transactions Table (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Related Party Transaction [Line Items]
Revenues and other		$ 383,141	$ 437,006	[1]
Equity income, net	[2],[3],[4]	16,814	18,220	[1]
Cost of product	[5]	76,467	139,408	[1]
Operation and maintenance	[5]	76,213	76,185	[1]
General and administrative	[5]	12,515	11,916	[1]
Operating expenses		247,158	578,388	[1]
Interest income	[6]	4,225	4,225	[1]
Interest expense	[7]	32,139	22,962	[1]
Distributions to unitholders	[8]	88,389	68,409	[1]
Above-market component of swap extensions with Anadarko	[8]	6,813	0	[1]
Affiliates [Member]
Related Party Transaction [Line Items]
Revenues and other	[4]	272,584	306,928	[1]
Cost of product	[4]	24,580	43,895
Operation and maintenance	[9]	17,975	16,817
General and administrative	[10]	9,150	8,335
Operating expenses		51,705	69,047
Interest expense	[11]	4,537	1,422
Affiliates [Member] | Western Gas Equity Partners, LP [Member]
Related Party Transaction [Line Items]
Distributions to unitholders	[12]	77,152	60,434
Affiliates [Member] | Western Gas Partners, LP [Member]
Related Party Transaction [Line Items]
Distributions to unitholders	[13]	$ 606	$ 530

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

[2] Income earned from equity investments is classified as affiliate. See Note 1.

[3] Income earned on, distributions from and contributions to equity investments are classified as affiliate. See Note 1.

[4] 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.

[5] Cost of product includes product purchases from Anadarko (as defined in Note 1) of $24.6 million and $43.9 million for the three months ended March 31, 2016 and 2015, respectively. Operation and maintenance includes charges from Anadarko of $18.0 million and $16.8 million for the three months ended March 31, 2016 and 2015, respectively. General and administrative includes charges from Anadarko of $9.2 million and $8.3 million for the three months ended March 31, 2016 and 2015, respectively. See Note 5.

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

[7] Includes affiliate (as defined in Note 1) interest expense of $4.5 million and $1.4 million for the three months ended March 31, 2016 and 2015, respectively. See Note 2 and Note 9.

[8] See Note 5.

[9] 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.

[10] 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.

[11] For the three months ended March 31, 2016 and 2015, includes WES’s accretion expense recognized on the Deferred purchase price obligation - Anadarko for the acquisition of DBJV (see Note 2 and Note 9) and for the three months ended March 31, 2015, includes interest expense recognized on the WGP WCF (see Note 9).

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

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