Consolidated Statements of Cash Flows - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2015		Sep. 30, 2014
Cash flows from operating activities
Net income		$ 361,264		$ 307,943	[1]
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and impairments		201,941		134,667	[1]
Non-cash equity-based compensation expense		3,453		3,333	[1]
Deferred income taxes		2,993		4,024	[1]
Accretion and amortization of long-term obligations, net		12,296		2,045	[1]
Equity income, net	[2],[3],[4]	(59,137)		(41,322)	[1]
Distributions from equity investment earnings	[3]	60,645		43,061	[1]
Gain on divestiture, net		(77,244)		0	[1]
Changes in assets and liabilities:
(Increase) decrease in accounts receivable, net		(24,265)		(52,681)	[1]
Increase (decrease) in accounts and natural gas imbalance payables and accrued liabilities, net		16,049		34,965	[1]
Change in other items, net		(1,184)		2,281	[1]
Net cash provided by operating activities		496,811		438,316	[1]
Cash flows from investing activities
Capital expenditures		(473,394)		(529,197)	[1]
Investments in equity affiliates		(9,052)		(63,267)	[1]
Distributions from equity investments in excess of cumulative earnings	[3]	12,409	[5]	14,387	[1]
Net cash used in investing activities		(337,989)		(950,282)	[1]
Cash flows from financing activities
Borrowings, net of debt issuance costs		769,606		1,136,878	[1]
Repayments of debt		(611,150)		(480,000)	[1]
Increase (decrease) in outstanding checks		(1,482)		2,908	[1]
Distributions to WGP unitholders		(223,016)		(164,725)	[1]
Net contributions from Anadarko		31,467		23,600	[1]
Above-market component of swap extensions with Anadarko	[6]	7,916		0	[1]
Net cash provided by (used in) financing activities		(151,193)		477,100	[1]
Net increase (decrease) in cash and cash equivalents		7,629		(34,866)	[1]
Cash and cash equivalents at beginning of period		67,213	[7]	113,085	[1]
Cash and cash equivalents at end of period		74,842		78,219	[1]
Supplemental disclosures
Net distributions to (contributions from) Anadarko of other assets		4,386		6,398	[1]
Interest paid, net of capitalized interest		60,612		43,504	[1]
Taxes paid (reimbursements received)		(138)		(340)	[1]
Capital lease asset transfer	[8]	0		4,833	[1]
Western Gas Partners, LP [Member]
Cash flows from financing activities
Proceeds from the issuance of WES common units, net of offering expenses		57,353		99,035	[1]
Distributions to noncontrolling interest owners of WES		(171,737)		(129,247)	[1]
Delaware Basin JV Gathering LLC [Member]
Cash flows from operating activities
Net income				14,238
Adjustments to reconcile net income to net cash provided by operating activities:
Equity income, net				0
Supplemental disclosures
Acquisition of DBJV from Anadarko	[9]	174,276		0	[1]
Chipeta Processing LLC [Member]
Cash flows from financing activities
Distributions to Chipeta noncontrolling interest owner		(10,150)		(11,349)	[1]
Affiliates [Member]
Cash flows from investing activities
Contributions in aid of construction costs from affiliates		0		183	[1]
Acquisitions		(12,131)		(372,393)	[1]
Proceeds from the sale of assets		700		0	[1]
Affiliates [Member] | Western Gas Partners, LP [Member]
Cash flows from financing activities
Distributions to WGP unitholders	[10]	(1,648)		(1,235)
Third Parties [Member]
Cash flows from investing activities
Acquisitions		(3,514)		0	[1]
Proceeds from the sale of assets		$ 146,993		$ 5	[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] 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.

[6] See Note 5.

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

[8] For the nine months ended September 30, 2014, represents transfers of $4.6 million from other long-term assets associated with the capital lease component of a processing agreement.

[9] See Note 2.

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