Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities
Net income	$ 282,387	$ 120,601	$ 180,215
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and impairments	145,916	120,608	113,133
Non-cash equity-based compensation expense	3,822	3,717	3,490
Deferred income taxes	(314)	(2,259)	(10,723)
Debt-related amortization and other items, net	2,449	2,319	3,110
Changes in assets and liabilities:
(Increase) decrease in accounts receivable, net	(34,148)	23,157	(44,725)
Increase (decrease) in accounts and natural gas imbalance payables and accrued liabilities, net	22,700	5,320	30,884
Change in other items, net	(10,512)	3,997	(16,495)
Net cash provided by operating activities	412,300	277,460	258,889
Cash flows from investing activities
Capital expenditures	(646,471)	(638,121)	(149,717)
Investments in equity affiliates	(51,974)	(862)	(93)
Other	(1,338)	0	(500)
Net cash used in investing activities	(1,416,066)	(1,249,942)	(479,722)
Cash flows from financing activities
Borrowings, net of debt issuance costs	957,503	1,041,648	1,055,939
Repayments of debt	(710,000)	(549,000)	(869,000)
Increase (decrease) in outstanding checks	(1,763)	1,800	4,039
Proceeds from the issuance of WGP common units, net of offering expenses	(2,367)	(412,020)	0
Distributions to WGP unitholders	(137,000)	0	0
Distributions to WES noncontrolling interest owners	(130,706)	(99,570)	(72,079)
Net contributions from Anadarko	4,458	137,844
Net distributions to Anadarko			(43,085)
Net cash provided by financing activities	694,295	1,168,479	420,318
Net increase (decrease) in cash and cash equivalents	(309,471)	195,997	199,485
Cash and cash equivalents at beginning of period	422,556	226,559	27,074
Cash and cash equivalents at end of period	113,085	422,556	226,559
Supplemental disclosures
Net distributions to Anadarko of other assets	5,855	15,296
Net contributions from Anadarko of other assets			(29)
Interest paid, net of capitalized interest	47,098	28,042	25,828
Taxes paid	552	495	190
Western Gas Partners [Member]
Cash flows from financing activities
Proceeds from issuance of WES common units, net of offering expenses	725,050	211,932	328,345
Affiliated Entity [Member]
Cash flows from investing activities
Contributions in aid of construction costs	617	0	0
Acquisitions	(476,711)	(611,719)	(28,837)
Proceeds from sale of assets to affiliates	85	760	382
Third Parties [Member]
Cash flows from investing activities
Acquisitions	(240,274)	0	(301,957)
Chipeta Processing Limited Liability Company [Member]
Cash flows from financing activities
Contributions received from Chipeta noncontrolling interest owners (including Anadarko)	2,247	29,108	33,637
Distributions to Chipeta noncontrolling interest owners (including Anadarko)	$ (13,127)	$ (17,303)	$ (17,478)