Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Cash flows from operating activities
Net income	$ 85,966		$ 93,796	[1]
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and impairments	70,292		42,085	[1]
Non-cash equity-based compensation expense	1,097		1,181	[1]
Deferred income taxes	3,758		993	[1]
Accretion and amortization of long-term obligations, net	2,112		680	[1]
Equity income, net	(18,220)	[2],[3],[4]	(9,251)	[1],[2],[3],[4]
Distributions from equity investment earnings	18,706	[3]	10,269	[1],[3]
Changes in assets and liabilities:
(Increase) decrease in accounts receivable, net	(17,798)		(15,434)	[1]
Increase (decrease) in accounts and natural gas imbalance payables and accrued liabilities, net	10,552		5,851	[1]
Change in other items, net	(1,010)		2,087	[1]
Net cash provided by operating activities	155,455		132,257	[1]
Cash flows from investing activities
Capital expenditures	(200,940)		(199,150)	[1]
Investments in equity affiliates	(4,878)		(28,462)	[1]
Distributions from equity investments in excess of cumulative earnings	2,964	[3],[5]	2,044	[1],[3]
Net cash used in investing activities	(203,960)		(586,520)	[1]
Cash flows from financing activities
Borrowings, net of debt issuance costs	140,000		917,742	[1]
Repayments of debt	(31,150)		(430,000)	[1]
Increase (decrease) in outstanding checks	(2,468)		1,928	[1]
Distributions to WGP unitholders	(68,409)		(50,621)	[1]
Net contributions from Anadarko	30,096		23,838	[1]
Net cash provided by financing activities	41,115		435,297	[1]
Net increase (decrease) in cash and cash equivalents	(7,390)		(18,966)	[1]
Cash and cash equivalents at beginning of period	67,213	[1]	113,085	[1]
Cash and cash equivalents at end of period	59,823		94,119	[1]
Supplemental disclosures
Net distributions to (contributions from) Anadarko of other assets	348		(43)	[1]
Interest paid, net of capitalized interest	17,596		14,106	[1]
Taxes paid (reimbursements received)	(138)		(340)	[1]
Western Gas Partners [Member]
Cash flows from financing activities
Proceeds from the issuance of WES common units, net of offering expenses	31,075		17,530	[1]
Distributions to noncontrolling interest owners of WES	(54,879)		(40,996)	[1]
Chipeta Processing Limited Liability Company [Member]
Cash flows from financing activities
Distributions to Chipeta noncontrolling interest owners	(3,150)		(4,124)	[1]
Affiliated Entity [Member]
Cash flows from investing activities
Acquisitions	(1,128)		(360,952)	[1]
Affiliated Entity [Member] | Western Gas Partners [Member]
Cash flows from financing activities
Distributions to WGP unitholders	(530)	[6]	(269)	[6]
Third Parties [Member]
Cash flows from investing activities
Proceeds from the sale of assets to third parties	22		0	[1]
Delaware Basin JV Gathering LLC [Member]
Cash flows from operating activities
Net income			3,621
Adjustments to reconcile net income to net cash provided by operating activities:
Equity income, net			0
Supplemental disclosures
Acquisition of DBJV from Anadarko	$ 174,276	[7]	$ 0	[7]

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

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

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

[7] See Note 2.