Consolidated Statements of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Cash flows from operating activities
Net income (loss)		$ (66,546)		$ 404,688	[1]	$ 285,974	[1]
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization		244,163		186,514	[1]	149,815	[1]
Impairments		514,096		3,084	[1]	1,267	[1]
Non-cash equity-based compensation expense		4,445		4,105	[1]	3,822	[1]
Deferred income taxes		1,932		13,325	[1]	40,035	[1]
Accretion and amortization of long-term obligations, net		17,698		2,736	[1]	2,449	[1]
Equity income, net	[2],[3],[4]	(71,251)		(57,836)	[1]	(22,948)	[1]
Distributions from equity investment earnings	[3]	82,054		62,967	[1]	17,698	[1]
Gain on divestiture and other, net	[5]	(57,020)		0	[1]	0	[1]
Lower of cost or market inventory adjustments		443		0	[1]	0	[1]
Changes in assets and liabilities:
(Increase) decrease in accounts receivable, net		(5,671)		(6,586)	[1]	(14,066)	[1]
Increase (decrease) in accounts and imbalance payables and accrued liabilities, net		3,154		(40,108)	[1]	29,615	[1]
Change in other items, net		(724)		3,487	[1]	(4,478)	[1]
Net cash provided by operating activities		666,773		576,376	[1]	489,183	[1]
Cash flows from investing activities
Capital expenditures		(602,289)		(722,443)	[1]	(681,999)	[1]
Investments in equity affiliates		(11,442)		(64,278)	[1]	(294,693)	[1]
Distributions from equity investments in excess of cumulative earnings	[3]	16,244	[6]	18,055	[1],[6]	4,438	[1]
Net cash used in investing activities		(466,424)		(2,670,998)	[1]	(1,688,523)	[1]
Cash flows from financing activities
Borrowings, net of debt issuance costs		889,606		1,648,028	[1]	957,503	[1]
Repayments of debt		(611,150)		(650,000)	[1]	(710,000)	[1]
Increase (decrease) in outstanding checks		(1,751)		1,693	[1]	(1,763)	[1]
Proceeds from the issuance of common units, net of offering expenses		0		0	[1]	(2,367)	[1]
Distributions to WGP unitholders	[7]	(306,477)		(228,481)	[1]	(137,000)	[1]
Net contributions from Anadarko		31,467		27,825	[1]	200,032	[1]
Above-market component of swap extensions with Anadarko	[7]	18,449		0	[1]	0	[1]
Net cash provided by (used in) financing activities		(167,868)		2,048,750	[1]	889,869	[1]
Net increase (decrease) in cash and cash equivalents		32,481		(45,872)	[1]	(309,471)	[1]
Cash and cash equivalents at beginning of period	[1]	67,213	[8]	113,085		422,556
Cash and cash equivalents at end of period		99,694		67,213	[1],[8]	113,085	[1]
Supplemental disclosures
Net distributions to (contributions from) Anadarko of other assets		4,767		10,733	[1]	5,855	[1]
Interest paid, net of capitalized interest		94,720		67,648	[1]	47,098	[1]
Taxes paid (reimbursements received)		0		(90)	[1]	552	[1]
Capital lease asset transfer		0		4,833	[1],[9]	0	[1]
Delaware Basin JV Gathering LLC [Member]
Cash flows from operating activities
Net income (loss)				17,309		4,096
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Equity income, net				0		0
Supplemental disclosures
Acquisition of DBJV from Anadarko		174,276		0	[1]	0	[1]
Chipeta Processing Limited Liability Company [Member]
Cash flows from financing activities
Contributions from Chipeta noncontrolling interest owner		0		0	[1]	2,247	[1]
Distributions to Chipeta noncontrolling interest owner		(12,187)		(15,149)	[1]	(13,127)	[1]
Western Gas Partners, LP [Member]
Cash flows from financing activities
Proceeds from the issuance of common units, net of offering expenses		57,353		691,178	[1]	725,050	[1]
Distributions to noncontrolling interest owners of WES		(233,178)		(176,344)	[1]	(130,706)	[1]
Western Gas Partners, LP [Member] | Class C Units [Member]
Cash flows from financing activities
Proceeds from the issuance of WES Class C units		0		750,000	[1]	0	[1]
Affiliates [Member]
Cash flows from investing activities
Contributions in aid of construction costs from affiliates		461		183	[1]	617	[1]
Acquisitions		(12,664)		(379,193)	[1]	(476,711)	[1]
Proceeds from the sale of assets		925		0	[1]	85	[1]
Affiliates [Member] | Western Gas Partners, LP [Member]
Cash flows from financing activities
Distributions to WGP unitholders	[10]	(2,235)		(1,747)		(755)
Third Parties [Member]
Cash flows from investing activities
Acquisitions		(3,514)		(1,523,327)	[1]	(240,274)	[1]
Proceeds from the sale of assets		$ 145,855		$ 5	[1]	$ 14	[1]

[1] Financial information has been recast to include the financial position and results attributable to the DBJV 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] Includes losses related to an incident at the DBM complex for the year ended December 31, 2015. See Note 1.

[6] Distributions in excess of cumulative earnings, classified as investing cash flows in the consolidated statements of cash flows, is calculated on an individual investment basis.

[7] See Note 5.

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

[9] For the year ended December 31, 2014, represents transfers of $4.6 million from other long-term assets associated with the capital lease component of a processing agreement. See Note 7

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