Western Midstream Partners 10-Q 27 Jul 16 2016 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2016	Jul. 25, 2016
Document And Entity Information [Abstract]
Trading Symbol	WES
Entity Registrant Name	Western Gas Partners LP
Entity Central Index Key	1,414,475
Document Type	10-Q
Document Period End Date	Jun. 30, 2016
Amendment Flag	false
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Units Outstanding		130,671,970

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015		Jun. 30, 2016	Jun. 30, 2015
Revenues and Other
Total revenues and other		$ 428,664	$ 465,993	[1]	$ 811,805	$ 902,999	[1]
Equity income, net – affiliates	[2]	19,693	18,941	[1]	36,507	37,161	[1]
Operating expenses
Cost of product	[3]	104,849	147,216	[1]	181,316	286,624	[1]
Operation and maintenance	[3]	75,173	77,837	[1]	151,386	154,022	[1]
General and administrative	[3]	10,883	9,408	[1]	22,160	20,489	[1]
Property and other taxes		12,078	9,586	[1]	22,428	18,866	[1]
Depreciation and amortization		67,305	68,554	[1]	132,400	137,529	[1]
Impairments		2,403	1,620	[1]	8,921	274,244	[1]
Total operating expenses		272,691	314,221	[1]	518,611	891,774	[1]
Gain (loss) on divestiture and other, net		(1,907)	0	[1]	(2,539)	(6)	[1]
Proceeds from business interruption insurance claims		2,603	0	[1]	2,603	0	[1]
Operating income (loss)		176,362	170,713	[1]	329,765	48,380	[1]
Interest income - affiliates	[4]	4,225	4,225	[1]	8,450	8,450	[1]
Interest expense	[5]	(12,883)	(27,604)	[1]	(44,919)	(50,564)	[1]
Other income (expense), net		(53)	71	[1]	71	142	[1]
Income (loss) before income taxes		167,651	147,405	[1]	293,367	6,408	[1]
Income tax (benefit) expense		326	12,246	[1]	6,959	24,516	[1]
Net income (loss)		167,325	135,159	[1]	286,408	(18,108)	[1]
Net income attributable to noncontrolling interest		2,804	2,816	[1]	5,827	6,042	[1]
Net income (loss) attributable to Western Gas Partners, LP		164,521	132,343	[1]	280,581	(24,150)	[1]
Limited partners' interest in net income (loss):
Pre-acquisition net (income) loss allocated to Anadarko		0	(18,719)	[1]	(11,326)	(43,758)	[1]
General partner interest in net (income) loss	[6]	$ (58,381)	$ (45,971)	[1]	$ (113,781)	$ (83,148)	[1]
Net income (loss) per common unit – basic and diluted	[7],[8]	$ 0.55	$ 0.46	[1]	$ 0.86	$ (1.14)	[1]
Series A Preferred Units [Member]
Limited partners' interest in net income (loss):
Limited partners’ interest in net income (loss)	[6],[9]	$ (23,121)	$ 0	[1]	$ (25,450)	$ 0	[1]
Common and Class C Units [Member]
Limited partners' interest in net income (loss):
Limited partners’ interest in net income (loss)	[6]	(83,019)	(67,653)	[1]	(130,024)	151,056	[1]
Affiliates [Member]
Revenues and Other
Gathering, processing and transportation		186,733	199,666	[1]	374,451	387,684	[1]
Natural gas and natural gas liquids sales		115,672	121,613	[1]	200,538	240,353	[1]
Other		0	132	[1]	0	302	[1]
Total revenues and other	[2]	302,405	321,411	[1]	574,989	628,339	[1]
Operating expenses
Cost of product	[2]	22,145	53,062		46,725	96,957
Operation and maintenance	[10]	17,661	19,854		35,636	36,671
General and administrative	[11]	9,169	8,060		18,121	16,195
Total operating expenses		48,975	80,976		100,482	149,823
Interest expense	[12]	15,461	(4,190)		10,924	(5,610)
Third Parties [Member]
Revenues and Other
Gathering, processing and transportation		114,403	91,234	[1]	220,689	173,484	[1]
Natural gas and natural gas liquids sales		11,321	52,589	[1]	15,011	99,521	[1]
Other		535	759	[1]	1,116	1,655	[1]
Total revenues and other		126,259	144,582	[1]	236,816	274,660	[1]
Operating expenses
Interest expense		$ (28,344)	$ (23,414)		$ (55,843)	$ (44,954)
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.
[2]	Represents amounts earned or incurred on and subsequent to the date of acquisition of the Partnership assets, as well as amounts earned or incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets, recognized under gathering, treating or processing agreements, and purchase and sale agreements.
[3]	Cost of product includes product purchases from Anadarko (as defined in Note 1) of $22.1 million and $46.7 million for the three and six months ended June 30, 2016, respectively, and $53.1 million and $97.0 million for the three and six months ended June 30, 2015, respectively. Operation and maintenance includes charges from Anadarko of $17.7 million and $35.6 million for the three and six months ended June 30, 2016, respectively, and $19.9 million and $36.7 million for the three and six months ended June 30, 2015, respectively. General and administrative includes charges from Anadarko of $9.2 million and $18.1 million for the three and six months ended June 30, 2016, respectively, and $8.1 million and $16.2 million for the three and six months ended June 30, 2015, respectively. See Note 5.
[4]	Represents interest income recognized on the note receivable from Anadarko.
[5]	Includes affiliate (as defined in Note 1) amounts of $(15.5) million and $(10.9) million for the three and six months ended June 30, 2016, respectively, and $4.2 million and $5.6 million for the three and six months ended June 30, 2015, respectively. See Note 2 and Note 9.
[6]	Represents net income (loss) earned on and subsequent to the date of acquisition of the Partnership assets (as defined in Note 1). See Note 4.
[7]	See Note 4 for the calculation of net income (loss) per common unit.
[8]	The impact of Class C units and the conversion of Series A Preferred units would be anti-dilutive.
[9]	Adjusted to reflect amortization of the beneficial conversion features.
[10]	Represents expenses incurred on and subsequent to the date of the acquisition of the Partnership assets, as well as expenses incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets.
[11]	Represents general and administrative expense incurred on and subsequent to the date of the Partnership’s acquisition of the Partnership assets, as well as a management services fee for reimbursement of expenses incurred by Anadarko for periods prior to the acquisition of the Partnership assets by the Partnership. These amounts include equity-based compensation expense allocated to the Partnership by Anadarko (see WES LTIP and WGP LTIP and Anadarko Incentive Plans within this Note 5).
[12]	For the three and six months ended June 30, 2016, includes accretion revisions to the Deferred purchase price obligation - Anadarko (see Note 2 and Note 9).

Consolidated Statements of Ope3

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015		Jun. 30, 2016	Jun. 30, 2015
Cost of product	[1]	$ 104,849	$ 147,216	[2]	$ 181,316	$ 286,624	[2]
Operation and maintenance	[1]	75,173	77,837	[2]	151,386	154,022	[2]
General and administrative	[1]	10,883	9,408	[2]	22,160	20,489	[2]
Interest expense	[3]	12,883	27,604	[2]	44,919	50,564	[2]
Affiliates [Member]
Cost of product	[4]	22,145	53,062		46,725	96,957
Operation and maintenance	[5]	17,661	19,854		35,636	36,671
General and administrative	[6]	9,169	8,060		18,121	16,195
Interest expense	[7]	$ (15,461)	$ 4,190		$ (10,924)	$ 5,610
[1]	Cost of product includes product purchases from Anadarko (as defined in Note 1) of $22.1 million and $46.7 million for the three and six months ended June 30, 2016, respectively, and $53.1 million and $97.0 million for the three and six months ended June 30, 2015, respectively. Operation and maintenance includes charges from Anadarko of $17.7 million and $35.6 million for the three and six months ended June 30, 2016, respectively, and $19.9 million and $36.7 million for the three and six months ended June 30, 2015, respectively. General and administrative includes charges from Anadarko of $9.2 million and $18.1 million for the three and six months ended June 30, 2016, respectively, and $8.1 million and $16.2 million for the three and six months ended June 30, 2015, respectively. See Note 5.
[2]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.
[3]	Includes affiliate (as defined in Note 1) amounts of $(15.5) million and $(10.9) million for the three and six months ended June 30, 2016, respectively, and $4.2 million and $5.6 million for the three and six months ended June 30, 2015, respectively. See Note 2 and Note 9.
[4]	Represents amounts earned or incurred on and subsequent to the date of acquisition of the Partnership assets, as well as amounts earned or incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets, recognized under gathering, treating or processing agreements, and purchase and sale agreements.
[5]	Represents expenses incurred on and subsequent to the date of the acquisition of the Partnership assets, as well as expenses incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets.
[6]	Represents general and administrative expense incurred on and subsequent to the date of the Partnership’s acquisition of the Partnership assets, as well as a management services fee for reimbursement of expenses incurred by Anadarko for periods prior to the acquisition of the Partnership assets by the Partnership. These amounts include equity-based compensation expense allocated to the Partnership by Anadarko (see WES LTIP and WGP LTIP and Anadarko Incentive Plans within this Note 5).
[7]	For the three and six months ended June 30, 2016, includes accretion revisions to the Deferred purchase price obligation - Anadarko (see Note 2 and Note 9).

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Jun. 30, 2016	Dec. 31, 2015	[1]
Current assets
Cash and cash equivalents		$ 157,767	$ 98,033
Accounts receivable, net	[2]	221,795	193,329
Other current assets		5,691	7,855
Total current assets		385,253	299,217
Note receivable - Anadarko		260,000	260,000
Property, plant and equipment
Cost		6,818,174	6,556,778
Less accumulated depreciation		1,816,030	1,697,999
Net property, plant and equipment		5,002,144	4,858,779
Goodwill		419,186	419,186
Other intangible assets		817,913	832,127
Equity investments		606,125	618,887
Other assets		13,481	13,001
Total assets		7,504,102	7,301,197
Current liabilities
Accounts and imbalance payables		90,914	98,661
Accrued ad valorem taxes		20,633	17,808
Accrued liabilities		130,018	119,019
Total current liabilities		241,565	235,488
Long-term debt		2,932,004	2,690,651
Deferred income taxes		6,020	139,704
Asset retirement obligations and other		137,139	128,652
Deferred purchase price obligation - Anadarko	[3]	29,150	188,674
Total long-term liabilities		3,104,313	3,147,681
Total liabilities		3,345,878	3,383,169
Equity and partners' capital
General partner units (2,583,068 units issued and outstanding at June 30, 2016, and December 31, 2015)		131,842	120,164
Net investment by Anadarko		0	430,598
Total partners' capital		4,092,473	3,850,644
Noncontrolling interest		65,751	67,384
Total equity and partners' capital		4,158,224	3,918,028
Total liabilities, equity and partners' capital		7,504,102	7,301,197
Series A Preferred Units [Member]
Equity and partners' capital
Series A Preferred units, Common units and Class C Units	[4]	617,094	0
Common Units [Member]
Equity and partners' capital
Series A Preferred units, Common units and Class C Units		2,613,806	2,588,991
Class C Units [Member]
Equity and partners' capital
Series A Preferred units, Common units and Class C Units	[5]	$ 729,731	$ 710,891
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.
[2]	Accounts receivable, net includes amounts receivable from affiliates (as defined in Note 1) of $81.3 million and $42.7 million as of June 30, 2016, and December 31, 2015, respectively. Accounts receivable, net as of June 30, 2016, and December 31, 2015, also includes an insurance claim receivable related to an incident at the DBM complex. See Note 1.
[3]	See Note 2.
[4]	The Series A Preferred units are convertible into common units at the holder’s election on a one-for-one basis at any time after the second anniversary of the issuance date. See Note 4.
[5]	The Class C units will convert into common units on a one-for-one basis on December 31, 2017, unless the Partnership elects to convert such units earlier or Anadarko extends the conversion date. See Note 4.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands		Jun. 30, 2016	Dec. 31, 2015
General partner units issued		2,583,068	2,583,068
General partner units outstanding		2,583,068	2,583,068
Accounts receivable, net	[1]	$ 221,795	$ 193,329	[2]
Series A Preferred Units [Member]
Units issued		21,922,831	0
Units outstanding		21,922,831	0
Common Units [Member]
Units issued		130,671,970	128,576,965
Units outstanding		130,671,970	128,576,965
Class C Units [Member]
Units issued		11,946,008	11,411,862
Units outstanding		11,946,008	11,411,862
Affiliates [Member]
Accounts receivable, net		$ 81,300	$ 42,700
[1]	Accounts receivable, net includes amounts receivable from affiliates (as defined in Note 1) of $81.3 million and $42.7 million as of June 30, 2016, and December 31, 2015, respectively. Accounts receivable, net as of June 30, 2016, and December 31, 2015, also includes an insurance claim receivable related to an incident at the DBM complex. See Note 1.
[2]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.

Consolidated Statement of Equit

Consolidated Statement of Equity and Partners' Capital - 6 months ended Jun. 30, 2016 - USD ($) $ in Thousands		Total	Net Investment by Anadarko [Member]	Common Units [Member]	Class C Units [Member]	Series A Preferred Units [Member]	General Partner Units [Member]	Noncontrolling Interest [Member]
Balance at Dec. 31, 2015	[1]	$ 3,918,028	$ 430,598	$ 2,588,991	$ 710,891	$ 0	$ 120,164	$ 67,384
Net income (loss)		286,408	11,326	126,292	13,213	15,969	113,781	5,827
Above-market component of swap extensions with Anadarko	[2]	16,365		16,365
Issuance of common units, net of offering expenses		25,000		25,000
Issuance of Series A Preferred units, net of offering expenses		686,940				686,940
Beneficial conversion feature of Series A Preferred units		0		93,409		(93,409)
Amortization of beneficial conversion feature of Class C units and Series A Preferred units		0		(15,108)	5,627	9,481
Distributions to noncontrolling interest owner		(7,460)						(7,460)
Distributions to unitholders		(313,380)		(209,355)		(1,887)	(102,138)
Acquisitions from affiliates		(712,500)	(549,865)	(162,635)
Revision to Deferred purchase price obligation – Anadarko	[3]	148,600		148,600
Contributions of equity-based compensation from Anadarko		2,053		2,012			41
Net pre-acquisition contributions from (distributions to) Anadarko		(27,459)	(27,459)
Net distributions to Anadarko of other assets		(354)		(348)			(6)
Elimination of net deferred tax liabilities		135,400	135,400
Other		583		583
Balance at Jun. 30, 2016		$ 4,158,224	$ 0	$ 2,613,806	$ 729,731	$ 617,094	$ 131,842	$ 65,751
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.
[2]	See Note 5.
[3]	See Note 2.

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2016		Jun. 30, 2015
Cash flows from operating activities
Net income (loss)		$ 286,408		$ (18,108)	[1]
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization		132,400		137,529	[1]
Impairments		8,921		274,244	[1]
Non-cash equity-based compensation expense		2,391		2,130	[1]
Deferred income taxes		1,980		6,382	[1]
Accretion and amortization of long-term obligations, net		(9,055)		7,070	[1]
Equity income, net – affiliates	[2]	(36,507)		(37,161)	[1]
Distributions from equity investment earnings – affiliates		38,519		39,034	[1]
(Gain) loss on divestiture and other, net		2,539		6	[1]
Changes in assets and liabilities:
(Increase) decrease in accounts receivable, net		(33,242)		(41,358)	[1]
Increase (decrease) in accounts and imbalance payables and accrued liabilities, net		(2,227)		4,407	[1]
Change in other items, net		1,739		(1,854)	[1]
Net cash provided by operating activities		393,866		372,321	[1]
Cash flows from investing activities
Capital expenditures		(255,923)		(361,798)	[1]
Investments in equity affiliates		139		(6,770)	[1]
Distributions from equity investments in excess of cumulative earnings – affiliates		10,611	[3]	8,538	[1]
Proceeds from property insurance claims		2,944		0	[1]
Net cash used in investing activities		(952,824)		(371,878)	[1]
Cash flows from financing activities
Borrowings, net of debt issuance costs		530,000		769,694	[1]
Repayments of debt		(290,000)		(520,000)	[1]
Increase (decrease) in outstanding checks		(1,314)		(2,938)	[1]
Proceeds from the issuance of common units, net of offering expenses		25,000		57,376	[1]
Distributions to unitholders	[4]	(313,380)		(259,247)	[1]
Distributions to noncontrolling interest owner		(7,460)		(7,175)	[1]
Net contributions from (distributions to) Anadarko		(27,459)		(17,439)	[1]
Above-market component of swap extensions with Anadarko	[4]	16,365		0	[1]
Net cash provided by (used in) financing activities		618,692		20,271	[1]
Net increase (decrease) in cash and cash equivalents		59,734		20,714	[1]
Cash and cash equivalents at beginning of period		98,033	[5]	67,054	[1]
Cash and cash equivalents at end of period		157,767		87,768	[1]
Supplemental disclosures
Net distributions to (contributions from) Anadarko of other assets		354		4,540	[1]
Interest paid, net of capitalized interest		53,973		42,165	[1]
Taxes paid (reimbursements received)		67		(138)	[1]
Delaware Basin JV Gathering LLC [Member]
Supplemental disclosures
Acquisition of DBJV from Anadarko		(159,524)		174,276	[1]
Series A Preferred Units [Member]
Cash flows from financing activities
Proceeds from the issuance of Series A Preferred units, net of offering expenses		686,940		0	[1]
Affiliates [Member]
Cash flows from investing activities
Contributions in aid of construction costs from affiliates		3,854		0	[1]
Acquisitions		(715,199)		(9,056)	[1]
Proceeds from the sale of assets		613		700	[1]
Cash flows from financing activities
Proceeds from the issuance of common units, net of offering expenses	[6]	25,000		0
Distributions to unitholders	[7]	(184,678)		(148,048)
Third Parties [Member]
Cash flows from investing activities
Acquisitions		0		(3,514)	[1]
Proceeds from the sale of assets		$ 137		$ 22	[1]
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.
[2]	Represents amounts earned or incurred on and subsequent to the date of acquisition of the Partnership assets, as well as amounts earned or incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets, recognized under gathering, treating or processing agreements, and purchase and sale agreements.
[3]	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.
[4]	See Note 5.
[5]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.
[6]	Represents proceeds from the issuance of 835,841 common units to WGP as partial funding for the acquisition of Springfield (see Note 2).
[7]	Represents distributions paid under the partnership agreement (see Note 3 and Note 4).

Description of Business and Bas

Description of Business and Basis of Presentation	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Description of Business and Basis of Presentation	General. Western Gas Partners, LP is a growth-oriented Delaware master limited partnership (“MLP”) formed by Anadarko Petroleum Corporation in 2007 to acquire, own, develop and operate midstream energy assets. For purposes of these consolidated financial statements, the “Partnership” refers to Western Gas Partners, LP and its subsidiaries. The Partnership’s general partner, Western Gas Holdings, LLC (the “general partner”), is owned by Western Gas Equity Partners, LP (“WGP”), a Delaware MLP formed by Anadarko Petroleum Corporation in September 2012 to own the Partnership’s general partner, as well as a significant limited partner interest in the Partnership (see Western Gas Equity Partners, LP below). WGP has no independent operations or material assets other than owning the partnership interests in WES (see Holdings of Partnership equity in Note 4 ). Western Gas Equity Holdings, LLC is WGP’s general partner and is a wholly owned subsidiary of Anadarko Petroleum Corporation. “Anadarko” refers to Anadarko Petroleum Corporation and its subsidiaries, excluding the Partnership and the general partner, and “affiliates” refers to subsidiaries of Anadarko, excluding the Partnership, but including equity interests in Fort Union Gas Gathering, LLC (“Fort Union”), White Cliffs Pipeline, LLC (“White Cliffs”), Rendezvous Gas Services, LLC (“Rendezvous”), Enterprise EF78 LLC (the “Mont Belvieu JV”), Texas Express Pipeline LLC (“TEP”), Texas Express Gathering LLC (“TEG”) and Front Range Pipeline LLC (“FRP”). The interests in TEP, TEG and FRP are referred to collectively as the “TEFR Interests.” The “MGR assets” include the Red Desert complex, the Granger straddle plant and the interest in Rendezvous. The Partnership is engaged in the business of gathering, processing, compressing, treating and transporting natural gas, condensate, NGLs and crude oil for Anadarko, as well as for third-party producers and customers. As of June 30, 2016 , the Partnership’s assets and investments accounted for under the equity method consisted of the following: Owned and Operated Operated Interests Non-Operated Interests Equity Interests Gathering systems 12 4 5 2 Treating facilities 13 12 — 3 Natural gas processing plants/trains 19 5 — 2 NGL pipelines 2 — — 3 Natural gas pipelines 5 — — — Oil pipelines — 1 — 1 These assets and investments are located in the Rocky Mountains (Colorado, Utah and Wyoming), the Mid-Continent (Kansas and Oklahoma), North-central Pennsylvania and Texas. In May 2016, the Partnership commenced operation of Train IV, a processing plant, at the DBM complex. The Partnership is constructing Train V, an additional processing plant at the DBM complex, with operations expected to commence during the second half of 2016. The Partnership has also made progress payments toward the construction of another cryogenic unit at the DBM complex (Train VI). The Partnership is evaluating when construction of Train VI will start and believe the earliest the plant will be online is the first quarter of 2018. 1. DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (CONTINUED) Basis of presentation. The following table outlines the Partnership’s ownership interests and the accounting method of consolidation used in the Partnership’s consolidated financial statements: Percentage Interest Equity investments (1) Fort Union 14.81 % White Cliffs 10 % Rendezvous 22 % Mont Belvieu JV 25 % TEP 20 % TEG 20 % FRP 33.33 % Proportionate consolidation (2) Non-Operated Marcellus Interest systems 33.75 % Anadarko-Operated Marcellus Interest systems 33.75 % Newcastle system 50 % DBJV system 50 % Springfield system 50.1 % Full consolidation Chipeta (3) 75 % (1) Investments in non-controlled entities over which the Partnership exercises significant influence are accounted for under the equity method. “Equity investment throughput” refers to the Partnership’s share of average throughput for these investments. (2) The Partnership proportionately consolidates its associated share of the assets, liabilities, revenues and expenses attributable to these assets. (3) The 25% interest in Chipeta Processing LLC (“Chipeta”) held by a third-party member is reflected within noncontrolling interest in the consolidated financial statements. The consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”). The consolidated financial statements include the accounts of the Partnership and entities in which it holds a controlling financial interest. All significant intercompany transactions have been eliminated. In preparing financial statements in accordance with GAAP, management makes informed judgments and estimates that affect the reported amounts of assets, liabilities, revenues and expenses. Management evaluates its estimates and related assumptions regularly, using historical experience and other methods considered reasonable. Changes in facts and circumstances or additional information may result in revised estimates and actual results may differ from these estimates. Effects on the business, financial condition and results of operations resulting from revisions to estimates are recognized when the facts that give rise to the revisions become known. The information furnished herein reflects all normal recurring adjustments which are, in the opinion of management, necessary for a fair presentation of the consolidated financial statements, and certain prior-period amounts have been reclassified to conform to the current-year presentation. Certain information and note disclosures commonly included in annual financial statements have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Accordingly, the accompanying consolidated financial statements and notes should be read in conjunction with the Partnership’s 2015 Form 10-K, as filed with the SEC on February 25, 2016, certain sections of which were recast to reflect the results of the Springfield interest in the Partnership’s Current Report on Form 8-K, as filed with the SEC on June 10, 2016. Management believes that the disclosures made are adequate to make the information not misleading. 1. DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (CONTINUED) Presentation of Partnership assets. The term “Partnership assets” refers to the assets owned and interests accounted for under the equity method (see Note 7 ) by the Partnership as of June 30, 2016 . Because Anadarko controls the Partnership through its ownership and control of WGP, which owns the Partnership’s entire general partner interest, each acquisition of Partnership assets from Anadarko has been considered a transfer of net assets between entities under common control. As such, the Partnership assets acquired from Anadarko were initially recorded at Anadarko’s historic carrying value, which did not correlate to the total acquisition price paid by the Partnership. Further, after an acquisition of Partnership assets from Anadarko, the Partnership may be required to recast its financial statements to include the activities of such Partnership assets from the date of common control. See Note 2 . For those periods requiring recast, the consolidated financial statements for periods prior to the Partnership’s acquisition of the Partnership assets from Anadarko have been prepared from Anadarko’s historical cost-basis accounts and may not necessarily be indicative of the actual results of operations that would have occurred if the Partnership had owned the Partnership assets during the periods reported. Net income (loss) attributable to the Partnership assets acquired from Anadarko for periods prior to the Partnership’s acquisition of the Partnership assets is not allocated to the limited partners. Insurance recoveries. Involuntary conversions result from the loss of an asset because of some unforeseen event (e.g., destruction due to fire). Some of these events are insurable and result in property damage insurance recovery. Amounts the Partnership receives from insurance carriers are net of any deductibles related to the covered event. The Partnership records a receivable from insurance to the extent it recognizes a loss from an involuntary conversion event and the likelihood of recovering such loss is deemed probable. To the extent that any of the Partnership’s insurance claim receivables are later judged not probable of recovery (e.g., due to new information), such amounts are expensed. The Partnership recognizes gains on involuntary conversions when the amount received from insurance exceeds the net book value of the retired asset(s). In addition, the Partnership does not recognize a gain related to insurance recoveries until all contingencies related to such proceeds have been resolved, that is, a non-refundable cash payment is received from the insurance carrier or the Partnership has a binding settlement agreement with the carrier that clearly states that a non-refundable payment will be made. To the extent that an asset is rebuilt, the associated expenditures are capitalized, as appropriate, in the consolidated balance sheets and presented as capital expenditures in the Partnership’s consolidated statements of cash flows. With respect to business interruption insurance claims, the Partnership recognizes income only when non-refundable cash proceeds are received from insurers, which are presented in the Partnership’s consolidated statements of operations as a component of Operating income (loss). On December 3, 2015, there was an initial fire and secondary explosion at the processing facility within the DBM complex. The majority of the damage from the incident was to the liquid handling facilities and the amine treating units at the inlet of the complex. Train II (with capacity of 100 MMcf/d) sustained the most damage of the processing trains but is expected to be returned to service by the end of 2016. Train III (with capacity of 200 MMcf/d) experienced minimal damage and returned to full service in May 2016. As of June 30, 2016 , and December 31, 2015, the consolidated balance sheets include receivables of $44.2 million and $49.0 million , respectively, for a property insurance claim related to the incident at the DBM complex. As of June 30, 2016 , the Partnership had received $5.5 million in cash proceeds from insurers related to the incident at the DBM complex, including $2.6 million in proceeds from business interruption insurance claims and $2.9 million in proceeds from property insurance claims. Recently issued accounting standards . The Financial Accounting Standards Board recently issued the following Accounting Standards Updates (“ASUs”): ASU 2016-02, Leases (Topic - 842). This ASU requires the lessees to recognize a lease liability and a right-of-use asset for all leases, including operating leases, with a term greater than 12 months on the balance sheet and disclose key information about their leasing transactions. This ASU is effective for annual and interim periods beginning in 2019. The Partnership is evaluating the impact of the adoption of this ASU on its consolidated financial statements. 1. DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (CONTINUED) ASU 2015-06, Earnings Per Share (Topic - 260)—Effects on Historical Earnings per Unit of Master Limited Partnership Dropdown Transactions . This ASU provides guidance for the presentation of historical earnings per unit for MLPs that apply the two-class method of calculating earnings per unit. When a general partner transfers or “drops down” net assets to an MLP, the transaction is accounted for as a transaction between entities under common control, and the statements of operations are adjusted retrospectively to reflect the transaction. This ASU specifies that the historical earnings (losses) of a transferred business before the date of a dropdown transaction should be allocated entirely to the general partner, and the previously reported earnings per unit of the limited partners should not change as a result of the dropdown transaction. The ASU also requires additional disclosures about how the rights to the earnings (losses) differ before and after the dropdown transaction occurs for purposes of computing earnings per unit under the two-class method. The Partnership applies the two-class method of calculating earnings per unit as described above (including the allocation of pre-acquisition net income (loss) to the general partner), and discloses the rights to earnings (losses) noted above. As such, there was no impact to the Partnership’s consolidated financial statements upon adoption of this ASU on January 1, 2016. ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30)—Simplifying the Presentation of Debt Issuance Costs and ASU 2015-15, Interest—Imputation of Interest (Subtopic 835-30)—Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements . These ASUs require capitalized debt issuance costs, except for those related to revolving credit facilities, to be presented in the balance sheet as a direct deduction from the carrying amount of the related debt liability, rather than as an asset. The Partnership adopted these ASUs on January 1, 2016, using a retrospective approach. The adoption resulted in a reclassification that reduced Other assets and Long-term debt by $16.7 million on the Partnership’s consolidated balance sheet at December 31, 2015. See Note 9 . ASU 2015-02, Consolidation (Topic 810)—Amendments to the Consolidation Analysis . This ASU amends existing requirements applicable to reporting entities that are required to evaluate consolidation of a legal entity under the variable interest entity (“VIE”) or voting interest entity models. The provisions will affect how limited partnerships and similar entities are assessed for consolidation, including an additional requirement that a limited partnership will be a VIE unless the limited partners have either substantive kick-out or participating rights over the general partner. The Partnership evaluated the impact of the adoption of this ASU on its consolidated financial statements and determined it does not have any entities for which it is the primary beneficiary for accounting and disclosure purposes. As such, the adoption of this ASU on January 1, 2016, did not impact the Partnership’s consolidated financial statements. ASU 2014-09, Revenue from Contracts with Customers (Topic 606). This ASU supersedes current revenue recognition requirements. The codification was amended through additional ASUs and, as amended, requires an entity to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration the entity expects to be entitled to in exchange for those goods or services. The Partnership is required to adopt the new standard in the first quarter of 2018 using one of two retrospective application methods. The Partnership is continuing to evaluate the provisions of this ASU and has not determined the impact this standard may have on its consolidated financial statements and related disclosures or decided upon the method of adoption.

Acquisitions and Divestitures

Acquisitions and Divestitures	6 Months Ended
	Jun. 30, 2016
Property, Plant and Equipment [Abstract]
Acquisitions and Divestitures	2. ACQUISITIONS AND DIVESTITURES The following table presents the acquisitions completed by the Partnership during 2016 and 2015 , and identifies the funding sources for such acquisitions: thousands except unit and percent amounts Acquisition Date Percentage Deferred Purchase Price Obligation - Anadarko Borrowings Common Units Issued Series A Preferred Units DBJV (1) 03/02/2015 100 % $ 174,276 $ — — — Springfield (2) 03/14/2016 100 % — 247,500 2,089,602 14,030,611 (1) The Partnership acquired Delaware Basin JV Gathering LLC (“DBJV”) from Anadarko. DBJV owns a 50% interest in a gathering system and related facilities. The DBJV gathering system and related facilities (the “DBJV system”) are located in the Delaware Basin in Loving, Ward, Winkler and Reeves Counties, Texas. The Partnership will make a cash payment on March 31, 2020, to Anadarko as consideration for the acquisition of DBJV. At the acquisition date, the Partnership estimated the future payment would be $282.8 million , the net present value of which was $174.3 million . For further information, including revisions to the estimated future payment, see DBJV acquisition—deferred purchase price obligation - Anadarko below. (2) The Partnership acquired Springfield Pipeline LLC (“Springfield”) from Anadarko for $750.0 million , consisting of $712.5 million in cash and the issuance of 1,253,761 of the Partnership’s common units. Springfield owns a 50.1% interest in an oil gathering system and a gas gathering system, such interest being referred to in this report as the “Springfield interest.” The Springfield oil and gas gathering systems (collectively, the “Springfield system”) are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. The Partnership financed the cash portion of the acquisition through: (i) borrowings of $247.5 million on the Partnership’s senior unsecured revolving credit facility (“RCF”), (ii) the issuance of 835,841 of the Partnership’s common units to WGP and (iii) the issuance of Series A Preferred units to private investors. See Note 4 for further information regarding the Series A Preferred units. Springfield acquisition . Because the acquisition of Springfield was a transfer of net assets between entities under common control, the Partnership’s historical financial statements and operational data previously filed with the SEC have been recast in this Form 10-Q to include the results attributable to the Springfield interest as if the Partnership owned Springfield for all periods presented. The consolidated financial statements for periods prior to the Partnership’s acquisition of Springfield have been prepared from Anadarko’s historical cost-basis accounts and may not necessarily be indicative of the actual results of operations that would have occurred if the Partnership had owned Springfield during the periods reported. The following table presents the impact of the Springfield interest on Revenues and other and Net income (loss) as presented in the Partnership’s historical consolidated statements of operations: Three Months Ended June 30, 2015 thousands Partnership Historical Springfield Interest Eliminations Combined Revenues and other $ 416,572 $ 49,438 $ (17 ) $ 465,993 Net income (loss) 116,440 18,719 — 135,159 Six Months Ended June 30, 2015 thousands Partnership Historical Springfield Interest Eliminations Combined Revenues and other $ 804,981 $ 98,051 $ (33 ) $ 902,999 Net income (loss) (60,124 ) 42,016 — (18,108 ) 2. ACQUISITIONS AND DIVESTITURES (CONTINUED) DBJV acquisition - deferred purchase price obligation - Anadarko. The consideration to be paid by the Partnership for the acquisition of DBJV consists of a cash payment to Anadarko due on March 31, 2020. The cash payment will be equal to (a) eight multiplied by the average of the Partnership’s share in the Net Earnings (see definition below) of DBJV for the calendar years 2018 and 2019, less (b) the Partnership’s share of all capital expenditures incurred for DBJV between March 1, 2015, and February 29, 2020. Net Earnings is defined as all revenues less cost of product, operating expenses and property taxes, in each case attributable to DBJV on an accrual basis. As of the acquisition date, the estimated future payment obligation (based on management’s estimate of the Partnership’s share of forecasted Net Earnings and capital expenditures for DBJV) was $282.8 million , which had a net present value of $174.3 million , using a discount rate of 10% . As of June 30, 2016 , the Partnership recognized a $241.1 million decrease in the estimated future payment obligation, resulting in a net present value of this obligation of $29.2 million , calculated using a discounted cash flow model with a 10% discount rate. The reduction in the value of the deferred purchase price obligation is primarily due to revisions reflecting a decrease in the Partnership’s estimate of 2018 and 2019 Net Earnings and an increase in the Partnership’s estimate of aggregate capital expenditures to be incurred by DBJV through February 29, 2020. The following table summarizes the financial statement impact of the Deferred purchase price obligation - Anadarko: Deferred purchase price obligation - Anadarko Estimated future payment obligation Balance at March 2, 2015 – Acquisition date $ 174,276 $ 282,807 Accretion expense (1) 14,398 Balance at December 31, 2015 188,674 Accretion expense (1) 4,537 Balance at March 31, 2016 193,211 Accretion revision (2) (15,461 ) Revision to Deferred purchase price obligation – Anadarko (3) (148,600 ) Balance at June 30, 2016 $ 29,150 $ 41,666 (1) Accretion expense was recorded as a charge to Interest expense on the consolidated statements of operations. (2) Interest expense on the consolidated statements of operations includes financing-related accretion revisions of $15.5 million and $10.9 million for the three and six months ended June 30, 2016 , respectively. (3) Recorded as revisions within Common units on the consolidated balance sheets and consolidated statement of equity and partners’ capital.

Partnership Distributions

Partnership Distributions	6 Months Ended
	Jun. 30, 2016
Distributions Made to Members or Limited Partners [Abstract]
Partnership Distributions	3. PARTNERSHIP DISTRIBUTIONS The partnership agreement requires the Partnership to distribute all of its available cash (as defined in the partnership agreement) to unitholders of record on the applicable record date within 45 days of the end of each quarter. The Board of Directors of the general partner declared the following cash distributions to the Partnership’s common and general partner unitholders for the periods presented: thousands except per-unit amounts Quarters Ended Total Quarterly Distribution per Unit Total Quarterly Cash Distribution Date of Distribution 2015 March 31 $ 0.725 $ 133,203 May 2015 June 30 0.750 139,736 August 2015 September 30 0.775 146,160 November 2015 December 31 0.800 152,588 February 2016 2016 March 31 $ 0.815 $ 158,905 May 2016 June 30 (1) 0.830 162,827 August 2016 (1) On July 20, 2016 , the Board of Directors of the Partnership’s general partner declared a cash distribution to the Partnership’s unitholders of $0.830 per unit, or $162.8 million in aggregate, including incentive distributions, but excluding distributions on Class C units (see Class C unit distributions below) and Series A Preferred units (see Series A Preferred unit distributions below). The cash distribution is payable on August 12, 2016 , to unitholders of record at the close of business on August 1, 2016 . Class C unit distributions. The Class C units receive quarterly distributions at a rate equivalent to the Partnership’s common units. The distributions are paid in the form of additional Class C units (“PIK Class C units”) until the scheduled conversion date on December 31, 2017 (unless earlier converted), and the Class C units are disregarded with respect to distributions of the Partnership’s available cash until they are converted to common units. The number of additional PIK Class C units to be issued in connection with a distribution payable on the Class C units is determined by dividing the corresponding distribution attributable to the Class C units by the volume-weighted-average price of the Partnership’s common units for the ten days immediately preceding the payment date for the common unit distribution, less a 6% discount. The Partnership records the PIK Class C unit distributions at fair value at the time of issuance. This Level 2 fair value measurement uses the Partnership’s unit price as a significant input in the determination of the fair value. On May 13, 2016, the Partnership distributed 210,562 PIK Class C units to APC Midstream Holdings, LLC (“AMH”), the holder of the Class C units, for the quarterly distribution period ended March 31, 2016, and on February 11, 2016, the Partnership distributed 323,584 PIK Class C units to AMH for the quarterly distribution period ended December 31, 2015. Series A Preferred unit distributions. As further described in Note 4 , the Partnership issued Series A Preferred units representing limited partner interests in the Partnership to private investors in March 2016 and April 2016. The Series A Preferred unitholders receive quarterly distributions in cash equal to $0.68 per Series A Preferred unit, subject to certain adjustments. The holders of the Series A Preferred units are entitled to certain rights that are senior to the rights of holders of common and Class C units, such as rights to distributions and rights upon liquidation of the Partnership. No payment or distribution on any junior equity security of the Partnership, including common and Class C units, for any quarter is permitted prior to the payment in full of the Series A Preferred unit distribution (including any outstanding arrearages). For the quarter ended June 30, 2016, the Series A Preferred unitholders will receive an aggregate cash distribution of $14.1 million comprised of a quarterly per unit distribution prorated for the 77 -day period 7,892,220 Series A Preferred units were outstanding during the second quarter of 2016 and a full quarterly per unit distribution on 14,030,611 Series A Preferred units. For the quarter ended March 31, 2016, the Series A Preferred unitholders received an aggregate cash distribution of $1.9 million , based on the quarterly per unit distribution prorated for the 18 -day period 14,030,611 Series A Preferred units were outstanding during the first quarter of 2016. See Note 4 for further discussion of the Series A Preferred units.

Equity and Partners' Capital

Equity and Partners' Capital	6 Months Ended
	Jun. 30, 2016
Partners' Capital Notes [Abstract]
Equity and Partners' Capital	4. EQUITY AND PARTNERS’ CAPITAL Equity offerings. Pursuant to the Partnership’s registration statement filed with the SEC in August 2014 authorizing the issuance of up to an aggregate of $500.0 million of common units (“$500.0 million COP”), during the year ended December 31, 2015, the Partnership issued 873,525 common units, at an average price of $66.61 , generating proceeds of $57.4 million (net of $0.8 million for the underwriting discount and other offering expenses). Net proceeds were used for general partnership purposes, including funding capital expenditures. Gross proceeds generated during the year ended December 31, 2015, were $58.2 million . Commissions paid during the year ended December 31, 2015, were $0.6 million . The Partnership issued no common units under the $500.0 million COP during the six months ended June 30, 2016 . Class C units. In connection with the closing of the DBM acquisition in November 2014, the Partnership issued 10,913,853 Class C units to AMH at a price of $68.72 per unit, generating proceeds of $750.0 million , pursuant to a Unit Purchase Agreement (“UPA”) with Anadarko and AMH. All outstanding Class C units will convert into common units on a one-for-one basis on December 31, 2017, unless the Partnership elects to convert such units earlier or Anadarko extends the conversion date. The Class C units were issued to partially fund the acquisition of DBM, and the UPA contains an optional redemption feature that provides the Partnership the ability to redeem up to $150.0 million of the Class C units within 10 days of the receipt of cash proceeds from an entity that is not an affiliate of the Partnership or AMH, if these cash proceeds were in relation to (i) the assets of DBM, (ii) the equity interests in DBM or (iii) the equity interests in a subsidiary of the Partnership that owns a majority of the outstanding equity interests in DBM. As of June 30, 2016 , no such proceeds had been received, and no Class C units had been redeemed. The Class C units were issued at a discount to the then-current market price of the common units into which they are convertible. This discount, totaling $34.8 million , represents a beneficial conversion feature, and at issuance, it was reflected as an increase in common unitholders’ capital and a decrease in Class C unitholder capital to reflect the fair value of the Class C units at issuance. The beneficial conversion feature is considered a non-cash distribution that will be recognized from the date of issuance through the date of conversion, resulting in an increase in Class C unitholder capital and a decrease in common unitholders’ capital as amortized. The beneficial conversion feature is amortized assuming a conversion date of December 31, 2017, using the effective yield method. The impact of the beneficial conversion feature amortization is also included in the calculation of earnings per unit. Series A Preferred units. In connection with the closing of the Springfield acquisition on March 14, 2016, the Partnership issued 14,030,611 Series A Preferred units (the “March 2016 Series A units”) to private investors for a cash purchase price of $32.00 per unit, generating proceeds of $440.0 million (net of fees and expenses, including a 2.0% transaction fee paid to the private investors). In April 2016, the Partnership issued an additional 7,892,220 Series A Preferred units (the “April 2016 Series A units”) pursuant to the full exercise of an option granted in connection with the March 2016 Series A units issuance, generating net proceeds of $246.9 million . The Series A Preferred unitholders may convert the Series A Preferred units into common units on a one -for-one basis at any time after the second anniversary of the issuance date, in whole or in part, subject to certain conversion thresholds. Similarly, the Partnership may convert the Series A Preferred units at any time after the third anniversary of the issuance date, in whole or in part, if the closing price of the Partnership’s common units is greater than $48.00 per common unit for 20 of the 30 preceding trading days, and subject to other certain conversion thresholds. In addition, upon certain events involving a change of control, the Series A Preferred unitholders may elect on an individual basis, subject to certain conditions, to (i) convert their Series A Preferred units to common units at the then applicable conversion rate, (ii) if the Partnership is not the surviving entity (or if the Partnership is the surviving entity, but its common units will cease to be listed), require the Partnership to use commercially reasonable efforts to cause the surviving entity in any such transaction to issue a substantially equivalent security (or convert into common units based on a specified formula, if the Partnership is unable to cause such substantially equivalent securities to be issued), (iii) if the Partnership is the surviving entity, continue to hold their Series A Preferred units, or (iv) require the Partnership to redeem the Series A Preferred units at a price per Series A Preferred unit of $32.32 , plus accrued and unpaid distributions to be paid in cash or common units at the discretion of the Partnership. 4. EQUITY AND PARTNERS’ CAPITAL (CONTINUED) The Series A Preferred unitholders will vote on an as-converted basis with the Partnership’s common unitholders and will have certain other class voting rights with respect to any amendment to the partnership agreement that would adversely affect any rights, preferences or privileges of the Series A Preferred unitholders. In connection with the issuance of the Series A Preferred units, the Partnership entered into a Registration Rights Agreement (the “Registration Rights Agreement”) with the Series A Preferred unit purchasers relating to the registered resale of the common units representing limited partner interests in the Partnership issuable upon conversion of the Series A Preferred units. Pursuant to the Registration Rights Agreement, the Partnership is required to use its commercially reasonable efforts to file and maintain a registration statement for the resale of the converted Series A Preferred units, with such registration statement to become effective no later than March 2018. The March 2016 Series A units and the April 2016 Series A units were issued at a discount to the then-current market price of the common units into which they are convertible. The discount on the March 2016 Series A units, totaling $21.7 million , represents a beneficial conversion feature, and on the date the Preferred Unit Purchase Agreement was signed (the “commitment date”), it was reflected as an increase in common unitholders’ capital and a decrease in Series A Preferred unitholders’ capital to reflect the fair value of the March 2016 Series A units on the commitment date. The discount on the April 2016 Series A units, totaling $71.7 million , also represents a beneficial conversion feature and on the date the option to purchase additional Series A units was exercised (the “notice date”), it was reflected as an increase in common unitholders’ capital and a decrease in Series A Preferred unitholders’ capital to reflect the fair value of the April 2016 Series A units on the notice date. The beneficial conversion features are considered non-cash distributions that will be recognized from each issuance date through the date of earliest conversion, resulting in an increase in Series A Preferred unitholders’ capital and a decrease in common unitholders’ capital as amortized. The beneficial conversion features are amortized assuming a conversion date of March 14, 2018 for the March 2016 Series A units and a conversion date of April 15, 2018 for the April 2016 Series A units, using the effective yield method. Partnership interests. The Partnership’s common units are listed on the New York Stock Exchange under the symbol “WES.” The following table summarizes the common, Class C, Series A Preferred and general partner units issued during the six months ended June 30, 2016 : Common Units Class C Units Series A Preferred Units General Partner Units Total Balance at December 31, 2015 128,576,965 11,411,862 — 2,583,068 142,571,895 PIK Class C units — 534,146 — — 534,146 Springfield acquisition 2,089,602 — 14,030,611 — 16,120,213 April 2016 Series A units — — 7,892,220 — 7,892,220 Long-Term Incentive Plan award vestings 5,403 — — — 5,403 Balance at June 30, 2016 130,671,970 11,946,008 21,922,831 2,583,068 167,123,877 4. EQUITY AND PARTNERS’ CAPITAL (CONTINUED) Holdings of Partnership equity. As of June 30, 2016 , WGP held 50,132,046 common units, representing a 30.0% limited partner interest in the Partnership, and, through its ownership of the general partner, WGP indirectly held 2,583,068 general partner units, representing a 1.5% general partner interest in the Partnership, and 100% of the IDRs. As of June 30, 2016 , other subsidiaries of Anadarko held 2,011,380 common units and 11,946,008 Class C units, representing an aggregate 8.4% limited partner interest in the Partnership. As of June 30, 2016 , the public held 78,528,544 common units, representing a 47.0% limited partner interest in the Partnership and private investors held 21,922,831 Series A Preferred units, representing a 13.1% limited partner interest in the Partnership. Net income (loss) per unit for common units. Net income (loss) attributable to Western Gas Partners, LP earned on and subsequent to the date of the acquisition of the Partnership assets, net of distributions on the Series A Preferred units and amortization of the Series A Preferred unit beneficial conversion features (see Series A Preferred units above), is allocated to the general partner, the common unitholders and the Class C unitholder, in accordance with their respective weighted-average ownership percentages (exclusive of the Series A Preferred unit limited partnership interest) and, when applicable, giving effect to incentive distributions allocable to the general partner. The allocable limited partners’ interest in net income (loss) is also net of amortization of the beneficial conversion feature related to the Class C units (see Class C units above) and is allocated between the common and Class C unitholders by applying the provisions of the partnership agreement that govern actual cash distributions and capital account allocations, as if all earnings for the period had been distributed. Net income (loss) attributable to the Partnership assets acquired from Anadarko for periods prior to the Partnership’s acquisition of the Partnership assets is not allocated to the limited partners for purposes of calculating net income (loss) per common unit. Basic net income (loss) per common unit is calculated by dividing the limited partners’ interest in net income (loss) attributable to common unitholders by the weighted-average number of common units outstanding during the period. The common units issued in connection with acquisitions and equity offerings are included on a weighted-average basis for periods they were outstanding. The Series A Preferred units are not considered a participating security as they only have distribution rights up to the specified per-unit quarterly distribution and have no rights to the Partnership’s undistributed earnings. Because the Class C units participate in distributions with common units according to a predetermined formula (see Note 3 ), they are considered a participating security and are included in the computation of earnings per unit pursuant to the two-class method. The Class C unit participation right results in a non-contingent transfer of value each time the Partnership declares a distribution. Diluted net income (loss) per common unit is calculated by dividing the sum of (i) the limited partners’ interest in net income (loss) attributable to common units adjusted for distributions on the Series A Preferred units and a reallocation of the limited partners’ interest in net income (loss) assuming conversion of the Series A Preferred units into common units, and (ii) the limited partners’ interest in net income (loss) allocable to the Class C units as a participating security, by the sum of the weighted-average number of common units outstanding plus the dilutive effect of (i) the weighted-average number of outstanding Class C units and (ii) the weighted-average number of common units outstanding assuming conversion of the Series A Preferred units. 4. EQUITY AND PARTNERS’ CAPITAL (CONTINUED) The following table illustrates the Partnership’s calculation of net income (loss) per unit for common units: Three Months Ended Six Months Ended thousands except per-unit amounts 2016 2015 2016 2015 Net income (loss) attributable to Western Gas Partners, LP $ 164,521 $ 132,343 $ 280,581 $ (24,150 ) Pre-acquisition net (income) loss allocated to Anadarko — (18,719 ) (11,326 ) (43,758 ) Series A Preferred units interest in net (income) loss (1) (23,121 ) — (25,450 ) — General partner interest in net (income) loss (58,381 ) (45,971 ) (113,781 ) (83,148 ) Common and Class C limited partners’ interest in net income (loss) $ 83,019 $ 67,653 $ 130,024 $ (151,056 ) Net income (loss) allocable to common units (1) $ 71,622 $ 59,119 $ 111,184 $ (146,139 ) Net income (loss) allocable to Class C units (1) 11,397 8,534 18,840 (4,917 ) Common and Class C limited partners’ interest in net income (loss) $ 83,019 $ 67,653 $ 130,024 $ (151,056 ) Net income (loss) per unit Common units – basic and diluted (2) $ 0.55 $ 0.46 $ 0.86 $ (1.14 ) Weighted-average units outstanding Common units – basic and diluted 130,669 128,481 129,830 128,111 Excluded due to anti-dilutive effect: Class C units 11,849 11,023 11,719 10,981 Series A Preferred units assuming conversion to common units 20,709 — 11,742 — (1) Adjusted to reflect amortization of the beneficial conversion features. (2) The impact of Class C units and the conversion of Series A Preferred units would be anti-dilutive.

Transactions with Affiliates

Transactions with Affiliates	6 Months Ended
	Jun. 30, 2016
Related Party Fees and Other Arrangements, Limited Liability Company (LLC) or Limited Partnership (LP) [Abstract]
Transactions with Affiliates	5. TRANSACTIONS WITH AFFILIATES Affiliate transactions. Revenues from affiliates include amounts earned by the Partnership from services provided to Anadarko as well as from the sale of residue and NGLs to Anadarko. In addition, the Partnership purchases natural gas from an affiliate of Anadarko pursuant to gas purchase agreements. Operation and maintenance expense includes amounts accrued for or paid to affiliates for the operation of the Partnership assets, whether in providing services to affiliates or to third parties, including field labor, measurement and analysis, and other disbursements. A portion of the Partnership’s general and administrative expenses is paid by Anadarko, which results in affiliate transactions pursuant to the reimbursement provisions of the Partnership’s omnibus agreement. Affiliate expenses do not bear a direct relationship to affiliate revenues, and third-party expenses do not bear a direct relationship to third-party revenues. See Note 2 for further information related to contributions of assets to the Partnership by Anadarko. Cash management. Anadarko operates a cash management system whereby excess cash from most of its subsidiaries’ separate bank accounts is generally swept to centralized accounts. Prior to the Partnership’s acquisition of the Partnership assets, third-party sales and purchases related to such assets were received or paid in cash by Anadarko within its centralized cash management system. The outstanding affiliate balances were entirely settled through an adjustment to net investment by Anadarko in connection with the acquisition of the Partnership assets. Subsequent to the acquisition of Partnership assets from Anadarko, transactions related to such assets are cash-settled directly with third parties and with Anadarko affiliates. Chipeta cash settles its transactions directly with third parties and Anadarko, as well as with the other subsidiaries of the Partnership. Note receivable - Anadarko and Deferred purchase price obligation - Anadarko. Concurrently with the closing of the Partnership’s May 2008 initial public offering, the Partnership loaned $260.0 million to Anadarko in exchange for a 30-year note bearing interest at a fixed annual rate of 6.50% , payable quarterly. The fair value of the note receivable from Anadarko was $301.5 million and $252.3 million at June 30, 2016 , and December 31, 2015, respectively. The fair value of the note reflects consideration of credit risk and any premium or discount for the differential between the stated interest rate and quarter-end market interest rate, based on quoted market prices of similar debt instruments. Accordingly, the fair value of the note receivable from Anadarko is measured using Level 2 inputs. The consideration to be paid by the Partnership to Anadarko for the March 2015 acquisition of DBJV consists of a cash payment due on March 31, 2020. See Note 2 and Note 9 . Commodity price swap agreements. The Partnership has commodity price swap agreements with Anadarko to mitigate exposure to a majority of the commodity price volatility that would otherwise be present as a result of the purchase and sale of natural gas, condensate or NGLs. Notional volumes for each of the commodity price swap agreements are not specifically defined. Instead, the commodity price swap agreements apply to the actual volume of natural gas, condensate and NGLs purchased and sold. The outstanding commodity price swap agreements for the Hugoton system, MGR assets and DJ Basin complex expire in December 2016. The commodity price swap agreements do not satisfy the definition of a derivative financial instrument and, therefore, are not required to be measured at fair value. Below is a summary of the fixed price ranges on all of the Partnership’s outstanding commodity price swap agreements as of June 30, 2016 : per barrel except natural gas 2016 Ethane $ 18.41 − 23.11 Propane 47.08 − 52.90 Isobutane 62.09 − 73.89 Normal butane 54.62 − 64.93 Natural gasoline 72.88 − 81.68 Condensate 76.47 − 81.68 Natural gas (per MMBtu) 4.87 − 5.96 5. TRANSACTIONS WITH AFFILIATES (CONTINUED) The following table summarizes gains and losses upon settlement of commodity price swap agreements recognized in the consolidated statements of operations: Three Months Ended Six Months Ended thousands 2016 2015 2016 2015 Gains (losses) on commodity price swap agreements related to sales: (1) Natural gas sales $ 5,202 $ 22,344 $ 12,243 $ 33,326 Natural gas liquids sales 20,480 38,297 40,550 82,729 Total 25,682 60,641 52,793 116,055 Losses on commodity price swap agreements related to purchases (2) (16,913 ) (41,720 ) (35,784 ) (75,899 ) Net gains (losses) on commodity price swap agreements $ 8,769 $ 18,921 $ 17,009 $ 40,156 (1) Reported in affiliate Natural gas and natural gas liquids sales in the consolidated statements of operations in the period in which the related sale is recorded. (2) Reported in Cost of product in the consolidated statements of operations in the period in which the related purchase is recorded. DJ Basin complex and Hugoton system swap extensions. On June 25, 2015, the Partnership extended its commodity price swap agreements with Anadarko for the DJ Basin complex from July 1, 2015, through December 31, 2015, and for the Hugoton system from October 1, 2015, through December 31, 2015. The table below summarizes the swap prices for the extension period compared to the forward market prices as of the agreement date, June 25, 2015. DJ Basin Complex Hugoton System per barrel except natural gas 2015 Swap Prices Market Prices (1) 2015 Swap Prices Market Prices (1) Ethane $ 18.41 $ 1.96 — — Propane 47.08 13.10 — — Isobutane 62.09 19.75 — — Normal butane 54.62 18.99 — — Natural gasoline 72.88 52.59 — — Condensate 76.47 52.59 $ 78.61 $ 32.56 Natural gas (per MMBtu) 5.96 2.75 5.50 2.74 (1) Represents the New York Mercantile Exchange (“NYMEX”) forward strip price as of June 25, 2015, adjusted for product specification, location, basis and, in the case of NGLs, transportation and fractionation costs. 5. TRANSACTIONS WITH AFFILIATES (CONTINUED) On December 8, 2015, the commodity price swap agreements with Anadarko for the DJ Basin complex and Hugoton system were further extended from January 1, 2016, through December 31, 2016. The table below summarizes the swap prices for the extension period compared to the forward market prices as of the agreement date, December 8, 2015. DJ Basin Complex Hugoton System per barrel except natural gas 2016 Swap Prices Market Prices (1) 2016 Swap Prices Market Prices (1) Ethane $ 18.41 $ 0.60 — — Propane 47.08 10.98 — — Isobutane 62.09 17.23 — — Normal butane 54.62 16.86 — — Natural gasoline 72.88 26.15 — — Condensate 76.47 34.65 $ 78.61 $ 18.81 Natural gas (per MMBtu) 5.96 2.11 5.50 2.12 (1) Represents the NYMEX forward strip price as of December 8, 2015, adjusted for product specification, location, basis and, in the case of NGLs, transportation and fractionation costs. Revenues or costs attributable to volumes settled during the respective extension period, at the applicable market price in the above tables, will be recognized in the consolidated statements of operations. The Partnership will also record a capital contribution from Anadarko in the Partnership’s consolidated statement of equity and partners’ capital for the amount by which the swap price exceeds the applicable market price in the above tables. For the six months ended June 30, 2016 , the capital contribution from Anadarko was $16.4 million . Gathering and processing agreements. The Partnership has significant gathering and processing arrangements with affiliates of Anadarko on a majority of its systems. The Partnership’s gathering, treating and transportation throughput (excluding equity investment throughput) attributable to natural gas production owned or controlled by Anadarko was 39% and 38% for the three and six months ended June 30, 2016 , respectively, and 56% for the three and six months ended June 30, 2015 . The Partnership’s processing throughput (excluding equity investment throughput) attributable to natural gas production owned or controlled by Anadarko was 55% and 58% for the three and six months ended June 30, 2016 , respectively, and 52% for the three and six months ended June 30, 2015 . The Partnership’s gathering, treating and transportation throughput (excluding equity investment throughput) attributable to crude/NGL production owned or controlled by Anadarko was 64% for the three and six months ended June 30, 2016 , and 100% for the three and six months ended June 30, 2015 . Prior to January 1, 2016, Springfield’s contracts were with a subsidiary of Anadarko who contracted with third parties. Effective January 1, 2016, Springfield’s contracts are with both a subsidiary of Anadarko and third parties directly. Commodity purchase and sale agreements. The Partnership sells a significant amount of its natural gas, condensate and NGLs to Anadarko Energy Services Company (“AESC”), Anadarko’s marketing affiliate. In addition, the Partnership purchases natural gas, condensate and NGLs from AESC pursuant to purchase agreements. The Partnership’s purchase and sale agreements with AESC are generally one-year contracts, subject to annual renewal. 5. TRANSACTIONS WITH AFFILIATES (CONTINUED) Acquisitions from Anadarko. On March 14, 2016, the Partnership acquired Springfield from Anadarko, and on March 2, 2015, the Partnership acquired DBJV from Anadarko. See Note 2 for further information on these acquisitions. WES LTIP. The general partner awards phantom units under the Western Gas Partners, LP 2008 Long-Term Incentive Plan (“WES LTIP”) primarily to its independent directors, but also from time to time to its executive officers and Anadarko employees performing services for the Partnership. The phantom units awarded to the independent directors vest one year from the grant date, while all other awards are subject to graded vesting over a three -year service period. Compensation expense is recognized over the vesting period and was $0.1 million for each of the three months ended June 30, 2016 and 2015, and $0.2 million for each of the six months ended June 30, 2016 and 2015. WGP LTIP and Anadarko Incentive Plans. General and administrative expenses included $1.1 million and $2.4 million for the three and six months ended June 30, 2016 , respectively, and $1.0 million and $2.0 million for the three and six months ended June 30, 2015 , respectively, of equity-based compensation expense, allocated to the Partnership by Anadarko, for awards granted to the executive officers of the general partner and other employees under the Western Gas Equity Partners, LP 2012 Long-Term Incentive Plan (“WGP LTIP”) and the Anadarko Petroleum Corporation 2008 and 2012 Omnibus Incentive Compensation Plans (referred to collectively as the “Anadarko Incentive Plans”). Of this amount, $2.1 million is reflected as a contribution to partners’ capital in the Partnership’s consolidated statement of equity and partners’ capital for the six months ended June 30, 2016 . Equipment purchases and sales. The following table summarizes the Partnership’s purchases from and sales to Anadarko of pipe and equipment: Six Months Ended June 30, 2016 2015 2016 2015 thousands Purchases Sales Cash consideration $ 2,699 $ 9,056 $ 613 $ 700 Net carrying value 2,328 4,182 596 366 Partners’ capital adjustment $ 371 $ 4,874 $ 17 $ 334 5. TRANSACTIONS WITH AFFILIATES (CONTINUED) Summary of affiliate transactions. The following table summarizes material affiliate transactions. See Note 2 for discussion of affiliate acquisitions and related funding. Three Months Ended Six Months Ended thousands 2016 2015 2016 2015 Revenues and other (1) $ 302,405 $ 321,411 $ 574,989 $ 628,339 Equity income, net – affiliates (1) 19,693 18,941 36,507 37,161 Cost of product (1) 22,145 53,062 46,725 96,957 Operation and maintenance (2) 17,661 19,854 35,636 36,671 General and administrative (3) 9,169 8,060 18,121 16,195 Operating expenses 48,975 80,976 100,482 149,823 Interest income (4) 4,225 4,225 8,450 8,450 Interest expense (5) (15,461 ) 4,190 (10,924 ) 5,610 Proceeds from the issuance of common units, net of offering expenses (6) — — 25,000 — Distributions to unitholders (7) 94,909 76,353 184,678 148,048 Above-market component of swap extensions with Anadarko 9,552 — 16,365 — (1) Represents amounts earned or incurred on and subsequent to the date of acquisition of the Partnership assets, as well as amounts earned or incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets, recognized under gathering, treating or processing agreements, and purchase and sale agreements. (2) Represents expenses incurred on and subsequent to the date of the acquisition of the Partnership assets, as well as expenses incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets. (3) Represents general and administrative expense incurred on and subsequent to the date of the Partnership’s acquisition of the Partnership assets, as well as a management services fee for reimbursement of expenses incurred by Anadarko for periods prior to the acquisition of the Partnership assets by the Partnership. These amounts include equity-based compensation expense allocated to the Partnership by Anadarko (see WES LTIP and WGP LTIP and Anadarko Incentive Plans within this Note 5 ). (4) Represents interest income recognized on the note receivable from Anadarko. (5) For the three and six months ended June 30, 2016 , includes accretion revisions to the Deferred purchase price obligation - Anadarko (see Note 2 and Note 9 ). (6) Represents proceeds from the issuance of 835,841 common units to WGP as partial funding for the acquisition of Springfield (see Note 2 ). (7) Represents distributions paid under the partnership agreement (see Note 3 and Note 4 ). Concentration of credit risk. Anadarko was the only customer from whom revenues exceeded 10% of the Partnership’s consolidated revenues for all periods presented in the consolidated statements of operations.

Property, Plant and Equipment

Property, Plant and Equipment	6 Months Ended
	Jun. 30, 2016
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	6. PROPERTY, PLANT AND EQUIPMENT A summary of the historical cost of the Partnership’s property, plant and equipment is as follows: thousands Estimated Useful Life June 30, 2016 December 31, 2015 Land n/a $ 3,946 $ 3,744 Gathering systems 3 to 47 years 6,409,489 6,061,004 Pipelines and equipment 15 to 45 years 135,319 136,290 Assets under construction n/a 239,617 329,887 Other 3 to 40 years 29,803 25,853 Total property, plant and equipment 6,818,174 6,556,778 Accumulated depreciation 1,816,030 1,697,999 Net property, plant and equipment $ 5,002,144 $ 4,858,779 The cost of property classified as “Assets under construction” is excluded from capitalized costs being depreciated. These amounts represent property that is not yet suitable to be placed into productive service as of the respective balance sheet date. As of June 30, 2016 , net property, plant and equipment includes impairments of $8.9 million , primarily due to an impairment of $6.1 million at the Newcastle system. This asset was impaired to its estimated fair value of $3.1 million , using the income approach and Level 3 fair value inputs, due to a reduction in estimated future cash flows caused by the low commodity price environment. Also during this period, the Partnership recognized impairments of $2.4 million , primarily related to the abandonment of compressors at the MIGC system.

Equity Investments

Equity Investments	6 Months Ended
	Jun. 30, 2016
Equity Method Investments and Joint Ventures [Abstract]
Equity Investments	7. EQUITY INVESTMENTS The following table presents the activity in the Partnership’s equity investments for the six months ended June 30, 2016 : Equity Investments thousands Fort White Rendezvous Mont TEG TEP FRP Total Balance at December 31, 2015 $ 17,122 $ 50,439 $ 50,913 $ 117,089 $ 16,283 $ 194,803 $ 172,238 $ 618,887 Investment earnings (loss), net of amortization (1,360 ) 7,164 949 12,686 343 7,766 8,959 36,507 Contributions — 441 — — — (580 ) — (139 ) Distributions — (6,873 ) (1,364 ) (12,303 ) (354 ) (7,892 ) (9,733 ) (38,519 ) Distributions in excess of cumulative earnings (1) (3,354 ) (2,100 ) (1,541 ) (172 ) (188 ) (2,918 ) (338 ) (10,611 ) Balance at June 30, 2016 $ 12,408 $ 49,071 $ 48,957 $ 117,300 $ 16,084 $ 191,179 $ 171,126 $ 606,125 (1) 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. During the six months ended June 30, 2016 , an impairment loss was recognized by the managing partner of Fort Union. The Partnership’s 14.81% share of the impairment loss was $3.0 million , which was recorded in Equity income, net – affiliates in the consolidated statements of operations.

Components of Working Capital

Components of Working Capital	6 Months Ended
	Jun. 30, 2016
Components Of Working Capital [Abstract]
Components of Working Capital	8. COMPONENTS OF WORKING CAPITAL A summary of accounts receivable, net is as follows: thousands June 30, 2016 December 31, 2015 Trade receivables, net $ 177,507 $ 143,557 Other receivables, net 44,288 49,772 Total accounts receivable, net $ 221,795 $ 193,329 A summary of other current assets is as follows: thousands June 30, 2016 December 31, 2015 Natural gas liquids inventory $ 4,032 $ 2,403 Imbalance receivables 1,359 2,122 Prepaid insurance 300 2,296 Other — 1,034 Total other current assets $ 5,691 $ 7,855 A summary of accrued liabilities is as follows: thousands June 30, 2016 December 31, 2015 Accrued capital expenditures $ 70,725 $ 61,454 Accrued plant purchases 27,149 16,425 Accrued interest expense 26,200 26,194 Short-term asset retirement obligations 2,713 3,677 Short-term remediation and reclamation obligations 1,136 1,136 Income taxes payable 1,127 770 Other 968 9,363 Total accrued liabilities $ 130,018 $ 119,019

Debt and Interest Expense

Debt and Interest Expense	6 Months Ended
	Jun. 30, 2016
Debt Instruments [Abstract]
Debt and Interest Expense	9. DEBT AND INTEREST EXPENSE At June 30, 2016 , the Partnership’s debt consisted of 5.375% Senior Notes due 2021 (the “2021 Notes”), 4.000% Senior Notes due 2022 (the “2022 Notes”), 2.600% Senior Notes due 2018 (the “2018 Notes”), 5.450% Senior Notes due 2044 (the “2044 Notes”), 3.950% Senior Notes due 2025 (the “2025 Notes”), and borrowings on the RCF. The following table presents the Partnership’s outstanding debt as of June 30, 2016 , and December 31, 2015 : June 30, 2016 December 31, 2015 thousands Principal Carrying Value Fair Value (1) Principal Carrying Value Fair Value (1) 2021 Notes $ 500,000 $ 494,215 $ 529,064 $ 500,000 $ 493,711 $ 513,645 2022 Notes 670,000 668,532 658,273 670,000 668,432 595,744 2018 Notes 350,000 348,946 348,908 350,000 348,706 339,293 2044 Notes 400,000 389,783 384,252 400,000 389,707 321,499 2025 Notes 500,000 490,528 479,690 500,000 490,095 422,285 RCF 540,000 540,000 540,000 300,000 300,000 300,000 Total long-term debt $ 2,960,000 $ 2,932,004 $ 2,940,187 $ 2,720,000 $ 2,690,651 $ 2,492,466 (1) Fair value is measured using the market approach and Level 2 inputs. Debt activity. The following table presents the debt activity of the Partnership for the six months ended June 30, 2016 : thousands Carrying Value Balance at December 31, 2015 $ 2,690,651 RCF borrowings 530,000 Repayments of RCF borrowings (290,000 ) Other 1,353 Balance at June 30, 2016 $ 2,932,004 Senior Notes. At June 30, 2016 , the Partnership was in compliance with all covenants under the indentures governing its outstanding notes. In July 2016, the Partnership issued $500.0 million aggregate principal amount of 4.650% Senior Notes due 2026 (the “2026 Notes”) which were offered at a price to the public of 99.796% of the face amount. Interest is paid semi-annually on January 1 and July 1 of each year. Proceeds (net of underwriting discount of $3.1 million , original issue discount and debt issuance costs) were used to repay a portion of the amount outstanding under the RCF. Revolving credit facility. The interest rate on the RCF, which matures in February 2019, was 1.77% and 1.49% at June 30, 2016 and 2015 , respectively. The facility fee rate was 0.20% at June 30, 2016 and 2015 . As of June 30, 2016 , the Partnership had $540.0 million of outstanding borrowings, $4.9 million in outstanding letters of credit and $655.1 million available for borrowing under the RCF. At June 30, 2016 , the Partnership was in compliance with all covenants under the RCF. In April 2016, the Partnership repaid $250.0 million of outstanding borrowings under the RCF, $246.9 million of which was funded with the proceeds from the issuance of the April 2016 Series A unit issuance (see Note 4 ). Interest rate agreements. In June 2016, the Partnership entered into a U.S. Treasury rate lock agreement to mitigate the risk of rising interest rates on existing variable-rate debt expected to be refinanced during the third quarter of 2016. The rate lock agreement was not designated as a cash flow hedge and was settled in June 2016 upon the offering of the 2026 Notes that closed in July 2016. The Partnership realized a loss of $0.2 million at settlement, which is included in Other income (expense), net in the Partnership’s consolidated statements of operations. 9. DEBT AND INTEREST EXPENSE (CONTINUED) Interest expense. The following table summarizes the amounts included in interest expense: Three Months Ended Six Months Ended thousands 2016 2015 2016 2015 Third parties Long-term debt $ 28,281 $ 24,733 $ 56,099 $ 48,075 Amortization of debt issuance costs and commitment fees 1,545 1,374 3,075 2,666 Capitalized interest (1,482 ) (2,693 ) (3,331 ) (5,787 ) Total interest expense – third parties 28,344 23,414 55,843 44,954 Affiliates Deferred purchase price obligation – Anadarko (1) (15,461 ) 4,190 (10,924 ) 5,610 Total interest expense – affiliates (15,461 ) 4,190 (10,924 ) 5,610 Interest expense $ 12,883 $ 27,604 $ 44,919 $ 50,564 (1) See Note 2 for a discussion of the accretion and net present value of the Deferred purchase price obligation - Anadarko.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. COMMITMENTS AND CONTINGENCIES Litigation and legal proceedings. From time to time, the Partnership is involved in legal, tax, regulatory and other proceedings in various forums regarding performance, contracts and other matters that arise in the ordinary course of business. Management is not aware of any such proceeding the final disposition of which could have a material adverse effect on the Partnership’s financial condition, results of operations or cash flows. Other commitments. The Partnership has short-term payment obligations, or commitments, related to its capital spending programs, as well as those of its unconsolidated affiliates. As of June 30, 2016 , the Partnership had unconditional payment obligations for services to be rendered or products to be delivered in connection with its capital projects of $38.3 million , the majority of which is expected to be paid in the next twelve months. These commitments relate primarily to the construction of Trains V and VI at the DBM complex and expansion projects at the DBJV system and the DJ Basin complex. Lease commitments. Anadarko, on behalf of the Partnership, has entered into lease agreements for corporate offices, shared field offices and a warehouse supporting the Partnership’s operations, for which Anadarko charges the Partnership rent. The leases for the corporate offices and shared field offices extend through 2017 and 2018, respectively, and the lease for the warehouse extends through February 2017. Rent expense associated with the office, warehouse and equipment leases was $8.4 million and $17.3 million for the three and six months ended June 30, 2016 , respectively, and $8.5 million and $16.5 million for the three and six months ended June 30, 2015 , respectively.

Description of Business and B18

Description of Business and Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Business combinations policy	Basis of presentation. The following table outlines the Partnership’s ownership interests and the accounting method of consolidation used in the Partnership’s consolidated financial statements: Percentage Interest Equity investments (1) Fort Union 14.81 % White Cliffs 10 % Rendezvous 22 % Mont Belvieu JV 25 % TEP 20 % TEG 20 % FRP 33.33 % Proportionate consolidation (2) Non-Operated Marcellus Interest systems 33.75 % Anadarko-Operated Marcellus Interest systems 33.75 % Newcastle system 50 % DBJV system 50 % Springfield system 50.1 % Full consolidation Chipeta (3) 75 % (1) Investments in non-controlled entities over which the Partnership exercises significant influence are accounted for under the equity method. “Equity investment throughput” refers to the Partnership’s share of average throughput for these investments. (2) The Partnership proportionately consolidates its associated share of the assets, liabilities, revenues and expenses attributable to these assets. (3) The 25% interest in Chipeta Processing LLC (“Chipeta”) held by a third-party member is reflected within noncontrolling interest in the consolidated financial statements. The consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”). The consolidated financial statements include the accounts of the Partnership and entities in which it holds a controlling financial interest. All significant intercompany transactions have been eliminated. Presentation of Partnership assets. The term “Partnership assets” refers to the assets owned and interests accounted for under the equity method (see Note 7 ) by the Partnership as of June 30, 2016 . Because Anadarko controls the Partnership through its ownership and control of WGP, which owns the Partnership’s entire general partner interest, each acquisition of Partnership assets from Anadarko has been considered a transfer of net assets between entities under common control. As such, the Partnership assets acquired from Anadarko were initially recorded at Anadarko’s historic carrying value, which did not correlate to the total acquisition price paid by the Partnership. Further, after an acquisition of Partnership assets from Anadarko, the Partnership may be required to recast its financial statements to include the activities of such Partnership assets from the date of common control. See Note 2 . For those periods requiring recast, the consolidated financial statements for periods prior to the Partnership’s acquisition of the Partnership assets from Anadarko have been prepared from Anadarko’s historical cost-basis accounts and may not necessarily be indicative of the actual results of operations that would have occurred if the Partnership had owned the Partnership assets during the periods reported. Net income (loss) attributable to the Partnership assets acquired from Anadarko for periods prior to the Partnership’s acquisition of the Partnership assets is not allocated to the limited partners.
Use of estimates policy	In preparing financial statements in accordance with GAAP, management makes informed judgments and estimates that affect the reported amounts of assets, liabilities, revenues and expenses. Management evaluates its estimates and related assumptions regularly, using historical experience and other methods considered reasonable. Changes in facts and circumstances or additional information may result in revised estimates and actual results may differ from these estimates. Effects on the business, financial condition and results of operations resulting from revisions to estimates are recognized when the facts that give rise to the revisions become known. The information furnished herein reflects all normal recurring adjustments which are, in the opinion of management, necessary for a fair presentation of the consolidated financial statements, and certain prior-period amounts have been reclassified to conform to the current-year presentation.
Recently issued accounting standards policy	Recently issued accounting standards . The Financial Accounting Standards Board recently issued the following Accounting Standards Updates (“ASUs”): ASU 2016-02, Leases (Topic - 842). This ASU requires the lessees to recognize a lease liability and a right-of-use asset for all leases, including operating leases, with a term greater than 12 months on the balance sheet and disclose key information about their leasing transactions. This ASU is effective for annual and interim periods beginning in 2019. The Partnership is evaluating the impact of the adoption of this ASU on its consolidated financial statements. 1. DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (CONTINUED) ASU 2015-06, Earnings Per Share (Topic - 260)—Effects on Historical Earnings per Unit of Master Limited Partnership Dropdown Transactions . This ASU provides guidance for the presentation of historical earnings per unit for MLPs that apply the two-class method of calculating earnings per unit. When a general partner transfers or “drops down” net assets to an MLP, the transaction is accounted for as a transaction between entities under common control, and the statements of operations are adjusted retrospectively to reflect the transaction. This ASU specifies that the historical earnings (losses) of a transferred business before the date of a dropdown transaction should be allocated entirely to the general partner, and the previously reported earnings per unit of the limited partners should not change as a result of the dropdown transaction. The ASU also requires additional disclosures about how the rights to the earnings (losses) differ before and after the dropdown transaction occurs for purposes of computing earnings per unit under the two-class method. The Partnership applies the two-class method of calculating earnings per unit as described above (including the allocation of pre-acquisition net income (loss) to the general partner), and discloses the rights to earnings (losses) noted above. As such, there was no impact to the Partnership’s consolidated financial statements upon adoption of this ASU on January 1, 2016. ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30)—Simplifying the Presentation of Debt Issuance Costs and ASU 2015-15, Interest—Imputation of Interest (Subtopic 835-30)—Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements . These ASUs require capitalized debt issuance costs, except for those related to revolving credit facilities, to be presented in the balance sheet as a direct deduction from the carrying amount of the related debt liability, rather than as an asset. The Partnership adopted these ASUs on January 1, 2016, using a retrospective approach. The adoption resulted in a reclassification that reduced Other assets and Long-term debt by $16.7 million on the Partnership’s consolidated balance sheet at December 31, 2015. See Note 9 . ASU 2015-02, Consolidation (Topic 810)—Amendments to the Consolidation Analysis . This ASU amends existing requirements applicable to reporting entities that are required to evaluate consolidation of a legal entity under the variable interest entity (“VIE”) or voting interest entity models. The provisions will affect how limited partnerships and similar entities are assessed for consolidation, including an additional requirement that a limited partnership will be a VIE unless the limited partners have either substantive kick-out or participating rights over the general partner. The Partnership evaluated the impact of the adoption of this ASU on its consolidated financial statements and determined it does not have any entities for which it is the primary beneficiary for accounting and disclosure purposes. As such, the adoption of this ASU on January 1, 2016, did not impact the Partnership’s consolidated financial statements. ASU 2014-09, Revenue from Contracts with Customers (Topic 606). This ASU supersedes current revenue recognition requirements. The codification was amended through additional ASUs and, as amended, requires an entity to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration the entity expects to be entitled to in exchange for those goods or services. The Partnership is required to adopt the new standard in the first quarter of 2018 using one of two retrospective application methods. The Partnership is continuing to evaluate the provisions of this ASU and has not determined the impact this standard may have on its consolidated financial statements and related disclosures or decided upon the method of adoption.
Net income (loss) per common unit policy	Net income (loss) per unit for common units. Net income (loss) attributable to Western Gas Partners, LP earned on and subsequent to the date of the acquisition of the Partnership assets, net of distributions on the Series A Preferred units and amortization of the Series A Preferred unit beneficial conversion features (see Series A Preferred units above), is allocated to the general partner, the common unitholders and the Class C unitholder, in accordance with their respective weighted-average ownership percentages (exclusive of the Series A Preferred unit limited partnership interest) and, when applicable, giving effect to incentive distributions allocable to the general partner. The allocable limited partners’ interest in net income (loss) is also net of amortization of the beneficial conversion feature related to the Class C units (see Class C units above) and is allocated between the common and Class C unitholders by applying the provisions of the partnership agreement that govern actual cash distributions and capital account allocations, as if all earnings for the period had been distributed. Net income (loss) attributable to the Partnership assets acquired from Anadarko for periods prior to the Partnership’s acquisition of the Partnership assets is not allocated to the limited partners for purposes of calculating net income (loss) per common unit. Basic net income (loss) per common unit is calculated by dividing the limited partners’ interest in net income (loss) attributable to common unitholders by the weighted-average number of common units outstanding during the period. The common units issued in connection with acquisitions and equity offerings are included on a weighted-average basis for periods they were outstanding. The Series A Preferred units are not considered a participating security as they only have distribution rights up to the specified per-unit quarterly distribution and have no rights to the Partnership’s undistributed earnings. Because the Class C units participate in distributions with common units according to a predetermined formula (see Note 3 ), they are considered a participating security and are included in the computation of earnings per unit pursuant to the two-class method. The Class C unit participation right results in a non-contingent transfer of value each time the Partnership declares a distribution. Diluted net income (loss) per common unit is calculated by dividing the sum of (i) the limited partners’ interest in net income (loss) attributable to common units adjusted for distributions on the Series A Preferred units and a reallocation of the limited partners’ interest in net income (loss) assuming conversion of the Series A Preferred units into common units, and (ii) the limited partners’ interest in net income (loss) allocable to the Class C units as a participating security, by the sum of the weighted-average number of common units outstanding plus the dilutive effect of (i) the weighted-average number of outstanding Class C units and (ii) the weighted-average number of common units outstanding assuming conversion of the Series A Preferred units.

Description of Business and B19

Description of Business and Basis of Presentation (Tables)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Assets and Investments Table	As of June 30, 2016 , the Partnership’s assets and investments accounted for under the equity method consisted of the following: Owned and Operated Operated Interests Non-Operated Interests Equity Interests Gathering systems 12 4 5 2 Treating facilities 13 12 — 3 Natural gas processing plants/trains 19 5 — 2 NGL pipelines 2 — — 3 Natural gas pipelines 5 — — — Oil pipelines — 1 — 1
Ownership Interest and Method of Consolidation Table	The following table outlines the Partnership’s ownership interests and the accounting method of consolidation used in the Partnership’s consolidated financial statements: Percentage Interest Equity investments (1) Fort Union 14.81 % White Cliffs 10 % Rendezvous 22 % Mont Belvieu JV 25 % TEP 20 % TEG 20 % FRP 33.33 % Proportionate consolidation (2) Non-Operated Marcellus Interest systems 33.75 % Anadarko-Operated Marcellus Interest systems 33.75 % Newcastle system 50 % DBJV system 50 % Springfield system 50.1 % Full consolidation Chipeta (3) 75 % (1) Investments in non-controlled entities over which the Partnership exercises significant influence are accounted for under the equity method. “Equity investment throughput” refers to the Partnership’s share of average throughput for these investments. (2) The Partnership proportionately consolidates its associated share of the assets, liabilities, revenues and expenses attributable to these assets. (3) The 25% interest in Chipeta Processing LLC (“Chipeta”) held by a third-party member is reflected within noncontrolling interest in the consolidated financial statements.

Acquisitions and Divestitures (

Acquisitions and Divestitures (Tables)	6 Months Ended
	Jun. 30, 2016
Property, Plant and Equipment [Abstract]
Acquisitions Table	The following table presents the acquisitions completed by the Partnership during 2016 and 2015 , and identifies the funding sources for such acquisitions: thousands except unit and percent amounts Acquisition Date Percentage Deferred Purchase Price Obligation - Anadarko Borrowings Common Units Issued Series A Preferred Units DBJV (1) 03/02/2015 100 % $ 174,276 $ — — — Springfield (2) 03/14/2016 100 % — 247,500 2,089,602 14,030,611 (1) The Partnership acquired Delaware Basin JV Gathering LLC (“DBJV”) from Anadarko. DBJV owns a 50% interest in a gathering system and related facilities. The DBJV gathering system and related facilities (the “DBJV system”) are located in the Delaware Basin in Loving, Ward, Winkler and Reeves Counties, Texas. The Partnership will make a cash payment on March 31, 2020, to Anadarko as consideration for the acquisition of DBJV. At the acquisition date, the Partnership estimated the future payment would be $282.8 million , the net present value of which was $174.3 million . For further information, including revisions to the estimated future payment, see DBJV acquisition—deferred purchase price obligation - Anadarko below. (2) The Partnership acquired Springfield Pipeline LLC (“Springfield”) from Anadarko for $750.0 million , consisting of $712.5 million in cash and the issuance of 1,253,761 of the Partnership’s common units. Springfield owns a 50.1% interest in an oil gathering system and a gas gathering system, such interest being referred to in this report as the “Springfield interest.” The Springfield oil and gas gathering systems (collectively, the “Springfield system”) are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. The Partnership financed the cash portion of the acquisition through: (i) borrowings of $247.5 million on the Partnership’s senior unsecured revolving credit facility (“RCF”), (ii) the issuance of 835,841 of the Partnership’s common units to WGP and (iii) the issuance of Series A Preferred units to private investors. See Note 4 for further information regarding the Series A Preferred units.
Impact to Historical Consolidated Statements of Income Table	The following table presents the impact of the Springfield interest on Revenues and other and Net income (loss) as presented in the Partnership’s historical consolidated statements of operations: Three Months Ended June 30, 2015 thousands Partnership Historical Springfield Interest Eliminations Combined Revenues and other $ 416,572 $ 49,438 $ (17 ) $ 465,993 Net income (loss) 116,440 18,719 — 135,159 Six Months Ended June 30, 2015 thousands Partnership Historical Springfield Interest Eliminations Combined Revenues and other $ 804,981 $ 98,051 $ (33 ) $ 902,999 Net income (loss) (60,124 ) 42,016 — (18,108 )
Impact of Deferred Purchase Price Obligation Table	The following table summarizes the financial statement impact of the Deferred purchase price obligation - Anadarko: Deferred purchase price obligation - Anadarko Estimated future payment obligation Balance at March 2, 2015 – Acquisition date $ 174,276 $ 282,807 Accretion expense (1) 14,398 Balance at December 31, 2015 188,674 Accretion expense (1) 4,537 Balance at March 31, 2016 193,211 Accretion revision (2) (15,461 ) Revision to Deferred purchase price obligation – Anadarko (3) (148,600 ) Balance at June 30, 2016 $ 29,150 $ 41,666 (1) Accretion expense was recorded as a charge to Interest expense on the consolidated statements of operations. (2) Interest expense on the consolidated statements of operations includes financing-related accretion revisions of $15.5 million and $10.9 million for the three and six months ended June 30, 2016 , respectively. (3) Recorded as revisions within Common units on the consolidated balance sheets and consolidated statement of equity and partners’ capital.

Partnership Distributions (Tabl

Partnership Distributions (Tables)	6 Months Ended
	Jun. 30, 2016
Distributions Made to Members or Limited Partners [Abstract]
Cash Distributions Table	The Board of Directors of the general partner declared the following cash distributions to the Partnership’s common and general partner unitholders for the periods presented: thousands except per-unit amounts Quarters Ended Total Quarterly Distribution per Unit Total Quarterly Cash Distribution Date of Distribution 2015 March 31 $ 0.725 $ 133,203 May 2015 June 30 0.750 139,736 August 2015 September 30 0.775 146,160 November 2015 December 31 0.800 152,588 February 2016 2016 March 31 $ 0.815 $ 158,905 May 2016 June 30 (1) 0.830 162,827 August 2016 (1) On July 20, 2016 , the Board of Directors of the Partnership’s general partner declared a cash distribution to the Partnership’s unitholders of $0.830 per unit, or $162.8 million in aggregate, including incentive distributions, but excluding distributions on Class C units (see Class C unit distributions below) and Series A Preferred units (see Series A Preferred unit distributions below). The cash distribution is payable on August 12, 2016 , to unitholders of record at the close of business on August 1, 2016 .

Equity and Partners' Capital (T

Equity and Partners' Capital (Tables)	6 Months Ended
	Jun. 30, 2016
Partners' Capital Notes [Abstract]
Partnership Interests Table	The following table summarizes the common, Class C, Series A Preferred and general partner units issued during the six months ended June 30, 2016 : Common Units Class C Units Series A Preferred Units General Partner Units Total Balance at December 31, 2015 128,576,965 11,411,862 — 2,583,068 142,571,895 PIK Class C units — 534,146 — — 534,146 Springfield acquisition 2,089,602 — 14,030,611 — 16,120,213 April 2016 Series A units — — 7,892,220 — 7,892,220 Long-Term Incentive Plan award vestings 5,403 — — — 5,403 Balance at June 30, 2016 130,671,970 11,946,008 21,922,831 2,583,068 167,123,877
Calculation of Net Income (Loss) Per Unit Table	The following table illustrates the Partnership’s calculation of net income (loss) per unit for common units: Three Months Ended Six Months Ended thousands except per-unit amounts 2016 2015 2016 2015 Net income (loss) attributable to Western Gas Partners, LP $ 164,521 $ 132,343 $ 280,581 $ (24,150 ) Pre-acquisition net (income) loss allocated to Anadarko — (18,719 ) (11,326 ) (43,758 ) Series A Preferred units interest in net (income) loss (1) (23,121 ) — (25,450 ) — General partner interest in net (income) loss (58,381 ) (45,971 ) (113,781 ) (83,148 ) Common and Class C limited partners’ interest in net income (loss) $ 83,019 $ 67,653 $ 130,024 $ (151,056 ) Net income (loss) allocable to common units (1) $ 71,622 $ 59,119 $ 111,184 $ (146,139 ) Net income (loss) allocable to Class C units (1) 11,397 8,534 18,840 (4,917 ) Common and Class C limited partners’ interest in net income (loss) $ 83,019 $ 67,653 $ 130,024 $ (151,056 ) Net income (loss) per unit Common units – basic and diluted (2) $ 0.55 $ 0.46 $ 0.86 $ (1.14 ) Weighted-average units outstanding Common units – basic and diluted 130,669 128,481 129,830 128,111 Excluded due to anti-dilutive effect: Class C units 11,849 11,023 11,719 10,981 Series A Preferred units assuming conversion to common units 20,709 — 11,742 — (1) Adjusted to reflect amortization of the beneficial conversion features. (2) The impact of Class C units and the conversion of Series A Preferred units would be anti-dilutive.

Transactions with Affiliates (T

Transactions with Affiliates (Tables)	6 Months Ended
	Jun. 30, 2016
Related Party Fees and Other Arrangements, Limited Liability Company (LLC) or Limited Partnership (LP) [Abstract]
Commodity Price Swap Agreements Table	Below is a summary of the fixed price ranges on all of the Partnership’s outstanding commodity price swap agreements as of June 30, 2016 : per barrel except natural gas 2016 Ethane $ 18.41 − 23.11 Propane 47.08 − 52.90 Isobutane 62.09 − 73.89 Normal butane 54.62 − 64.93 Natural gasoline 72.88 − 81.68 Condensate 76.47 − 81.68 Natural gas (per MMBtu) 4.87 − 5.96
Gains (Losses) on Commodity Price Swap Agreements Table	The following table summarizes gains and losses upon settlement of commodity price swap agreements recognized in the consolidated statements of operations: Three Months Ended Six Months Ended thousands 2016 2015 2016 2015 Gains (losses) on commodity price swap agreements related to sales: (1) Natural gas sales $ 5,202 $ 22,344 $ 12,243 $ 33,326 Natural gas liquids sales 20,480 38,297 40,550 82,729 Total 25,682 60,641 52,793 116,055 Losses on commodity price swap agreements related to purchases (2) (16,913 ) (41,720 ) (35,784 ) (75,899 ) Net gains (losses) on commodity price swap agreements $ 8,769 $ 18,921 $ 17,009 $ 40,156 (1) Reported in affiliate Natural gas and natural gas liquids sales in the consolidated statements of operations in the period in which the related sale is recorded. (2) Reported in Cost of product in the consolidated statements of operations in the period in which the related purchase is recorded.
Commodity Price Swap Agreements Extensions Tables	The table below summarizes the swap prices for the extension period compared to the forward market prices as of the agreement date, June 25, 2015. DJ Basin Complex Hugoton System per barrel except natural gas 2015 Swap Prices Market Prices (1) 2015 Swap Prices Market Prices (1) Ethane $ 18.41 $ 1.96 — — Propane 47.08 13.10 — — Isobutane 62.09 19.75 — — Normal butane 54.62 18.99 — — Natural gasoline 72.88 52.59 — — Condensate 76.47 52.59 $ 78.61 $ 32.56 Natural gas (per MMBtu) 5.96 2.75 5.50 2.74 (1) Represents the New York Mercantile Exchange (“NYMEX”) forward strip price as of June 25, 2015, adjusted for product specification, location, basis and, in the case of NGLs, transportation and fractionation costs. 5. TRANSACTIONS WITH AFFILIATES (CONTINUED) On December 8, 2015, the commodity price swap agreements with Anadarko for the DJ Basin complex and Hugoton system were further extended from January 1, 2016, through December 31, 2016. The table below summarizes the swap prices for the extension period compared to the forward market prices as of the agreement date, December 8, 2015. DJ Basin Complex Hugoton System per barrel except natural gas 2016 Swap Prices Market Prices (1) 2016 Swap Prices Market Prices (1) Ethane $ 18.41 $ 0.60 — — Propane 47.08 10.98 — — Isobutane 62.09 17.23 — — Normal butane 54.62 16.86 — — Natural gasoline 72.88 26.15 — — Condensate 76.47 34.65 $ 78.61 $ 18.81 Natural gas (per MMBtu) 5.96 2.11 5.50 2.12 (1) Represents the NYMEX forward strip price as of December 8, 2015, adjusted for product specification, location, basis and, in the case of NGLs, transportation and fractionation costs.
Related Party Transactions Tables	Equipment purchases and sales. The following table summarizes the Partnership’s purchases from and sales to Anadarko of pipe and equipment: Six Months Ended June 30, 2016 2015 2016 2015 thousands Purchases Sales Cash consideration $ 2,699 $ 9,056 $ 613 $ 700 Net carrying value 2,328 4,182 596 366 Partners’ capital adjustment $ 371 $ 4,874 $ 17 $ 334 5. TRANSACTIONS WITH AFFILIATES (CONTINUED) Summary of affiliate transactions. The following table summarizes material affiliate transactions. See Note 2 for discussion of affiliate acquisitions and related funding. Three Months Ended Six Months Ended thousands 2016 2015 2016 2015 Revenues and other (1) $ 302,405 $ 321,411 $ 574,989 $ 628,339 Equity income, net – affiliates (1) 19,693 18,941 36,507 37,161 Cost of product (1) 22,145 53,062 46,725 96,957 Operation and maintenance (2) 17,661 19,854 35,636 36,671 General and administrative (3) 9,169 8,060 18,121 16,195 Operating expenses 48,975 80,976 100,482 149,823 Interest income (4) 4,225 4,225 8,450 8,450 Interest expense (5) (15,461 ) 4,190 (10,924 ) 5,610 Proceeds from the issuance of common units, net of offering expenses (6) — — 25,000 — Distributions to unitholders (7) 94,909 76,353 184,678 148,048 Above-market component of swap extensions with Anadarko 9,552 — 16,365 — (1) Represents amounts earned or incurred on and subsequent to the date of acquisition of the Partnership assets, as well as amounts earned or incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets, recognized under gathering, treating or processing agreements, and purchase and sale agreements. (2) Represents expenses incurred on and subsequent to the date of the acquisition of the Partnership assets, as well as expenses incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets. (3) Represents general and administrative expense incurred on and subsequent to the date of the Partnership’s acquisition of the Partnership assets, as well as a management services fee for reimbursement of expenses incurred by Anadarko for periods prior to the acquisition of the Partnership assets by the Partnership. These amounts include equity-based compensation expense allocated to the Partnership by Anadarko (see WES LTIP and WGP LTIP and Anadarko Incentive Plans within this Note 5 ). (4) Represents interest income recognized on the note receivable from Anadarko. (5) For the three and six months ended June 30, 2016 , includes accretion revisions to the Deferred purchase price obligation - Anadarko (see Note 2 and Note 9 ). (6) Represents proceeds from the issuance of 835,841 common units to WGP as partial funding for the acquisition of Springfield (see Note 2 ). (7) Represents distributions paid under the partnership agreement (see Note 3 and Note 4 ).

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	6 Months Ended
	Jun. 30, 2016
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment Table	A summary of the historical cost of the Partnership’s property, plant and equipment is as follows: thousands Estimated Useful Life June 30, 2016 December 31, 2015 Land n/a $ 3,946 $ 3,744 Gathering systems 3 to 47 years 6,409,489 6,061,004 Pipelines and equipment 15 to 45 years 135,319 136,290 Assets under construction n/a 239,617 329,887 Other 3 to 40 years 29,803 25,853 Total property, plant and equipment 6,818,174 6,556,778 Accumulated depreciation 1,816,030 1,697,999 Net property, plant and equipment $ 5,002,144 $ 4,858,779

Equity Investments (Tables)

Equity Investments (Tables)	6 Months Ended
	Jun. 30, 2016
Equity Method Investments and Joint Ventures [Abstract]
Equity Investments Table	The following table presents the activity in the Partnership’s equity investments for the six months ended June 30, 2016 : Equity Investments thousands Fort White Rendezvous Mont TEG TEP FRP Total Balance at December 31, 2015 $ 17,122 $ 50,439 $ 50,913 $ 117,089 $ 16,283 $ 194,803 $ 172,238 $ 618,887 Investment earnings (loss), net of amortization (1,360 ) 7,164 949 12,686 343 7,766 8,959 36,507 Contributions — 441 — — — (580 ) — (139 ) Distributions — (6,873 ) (1,364 ) (12,303 ) (354 ) (7,892 ) (9,733 ) (38,519 ) Distributions in excess of cumulative earnings (1) (3,354 ) (2,100 ) (1,541 ) (172 ) (188 ) (2,918 ) (338 ) (10,611 ) Balance at June 30, 2016 $ 12,408 $ 49,071 $ 48,957 $ 117,300 $ 16,084 $ 191,179 $ 171,126 $ 606,125 (1) 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.

Components of Working Capital (

Components of Working Capital (Tables)	6 Months Ended
	Jun. 30, 2016
Components Of Working Capital [Abstract]
Accounts Receivable, Net Table	A summary of accounts receivable, net is as follows: thousands June 30, 2016 December 31, 2015 Trade receivables, net $ 177,507 $ 143,557 Other receivables, net 44,288 49,772 Total accounts receivable, net $ 221,795 $ 193,329
Other Current Assets Table	A summary of other current assets is as follows: thousands June 30, 2016 December 31, 2015 Natural gas liquids inventory $ 4,032 $ 2,403 Imbalance receivables 1,359 2,122 Prepaid insurance 300 2,296 Other — 1,034 Total other current assets $ 5,691 $ 7,855
Accrued Liabilities Table	A summary of accrued liabilities is as follows: thousands June 30, 2016 December 31, 2015 Accrued capital expenditures $ 70,725 $ 61,454 Accrued plant purchases 27,149 16,425 Accrued interest expense 26,200 26,194 Short-term asset retirement obligations 2,713 3,677 Short-term remediation and reclamation obligations 1,136 1,136 Income taxes payable 1,127 770 Other 968 9,363 Total accrued liabilities $ 130,018 $ 119,019

Debt and Interest Expense (Tabl

Debt and Interest Expense (Tables)	6 Months Ended
	Jun. 30, 2016
Debt Instruments [Abstract]
Debt Outstanding and Debt Activity Tables	The following table presents the Partnership’s outstanding debt as of June 30, 2016 , and December 31, 2015 : June 30, 2016 December 31, 2015 thousands Principal Carrying Value Fair Value (1) Principal Carrying Value Fair Value (1) 2021 Notes $ 500,000 $ 494,215 $ 529,064 $ 500,000 $ 493,711 $ 513,645 2022 Notes 670,000 668,532 658,273 670,000 668,432 595,744 2018 Notes 350,000 348,946 348,908 350,000 348,706 339,293 2044 Notes 400,000 389,783 384,252 400,000 389,707 321,499 2025 Notes 500,000 490,528 479,690 500,000 490,095 422,285 RCF 540,000 540,000 540,000 300,000 300,000 300,000 Total long-term debt $ 2,960,000 $ 2,932,004 $ 2,940,187 $ 2,720,000 $ 2,690,651 $ 2,492,466 (1) Fair value is measured using the market approach and Level 2 inputs. Debt activity. The following table presents the debt activity of the Partnership for the six months ended June 30, 2016 : thousands Carrying Value Balance at December 31, 2015 $ 2,690,651 RCF borrowings 530,000 Repayments of RCF borrowings (290,000 ) Other 1,353 Balance at June 30, 2016 $ 2,932,004
Interest Expense Table	The following table summarizes the amounts included in interest expense: Three Months Ended Six Months Ended thousands 2016 2015 2016 2015 Third parties Long-term debt $ 28,281 $ 24,733 $ 56,099 $ 48,075 Amortization of debt issuance costs and commitment fees 1,545 1,374 3,075 2,666 Capitalized interest (1,482 ) (2,693 ) (3,331 ) (5,787 ) Total interest expense – third parties 28,344 23,414 55,843 44,954 Affiliates Deferred purchase price obligation – Anadarko (1) (15,461 ) 4,190 (10,924 ) 5,610 Total interest expense – affiliates (15,461 ) 4,190 (10,924 ) 5,610 Interest expense $ 12,883 $ 27,604 $ 44,919 $ 50,564 (1) See Note 2 for a discussion of the accretion and net present value of the Deferred purchase price obligation - Anadarko.

Description of Business and B28

Description of Business and Basis of Presentation - Asset Table (Details)	Jun. 30, 2016unit
Operated [Member] | Gathering Systems [Member]
Assets [Line Items]
Assets, number of units	12
Operated [Member] | Treating Facilities [Member]
Assets [Line Items]
Assets, number of units	13
Operated [Member] | Natural Gas Processing Plants/Trains [Member]
Assets [Line Items]
Assets, number of units	19
Operated [Member] | Natural Gas Liquids Pipelines [Member]
Assets [Line Items]
Assets, number of units	2
Operated [Member] | Natural Gas Pipelines [Member]
Assets [Line Items]
Assets, number of units	5
Operated Interests [Member] | Gathering Systems [Member]
Assets [Line Items]
Assets, number of units	4
Operated Interests [Member] | Treating Facilities [Member]
Assets [Line Items]
Assets, number of units	12
Operated Interests [Member] | Natural Gas Processing Plants/Trains [Member]
Assets [Line Items]
Assets, number of units	5
Operated Interests [Member] | Oil Pipelines [Member]
Assets [Line Items]
Assets, number of units	1
Non-Operated Interests [Member] | Gathering Systems [Member]
Assets [Line Items]
Assets, number of units	5
Equity Interests [Member] | Gathering Systems [Member]
Assets [Line Items]
Assets, number of units	2
Equity Interests [Member] | Treating Facilities [Member]
Assets [Line Items]
Assets, number of units	3
Equity Interests [Member] | Natural Gas Processing Plants/Trains [Member]
Assets [Line Items]
Assets, number of units	2
Equity Interests [Member] | Natural Gas Liquids Pipelines [Member]
Assets [Line Items]
Assets, number of units	3
Equity Interests [Member] | Oil Pipelines [Member]
Assets [Line Items]
Assets, number of units	1

Description of Business and B29

Description of Business and Basis of Presentation - Ownership Interest and Method of Consolidation Table (Details)	6 Months Ended
	Jun. 30, 2016
Chipeta Processing Limited Liability Company [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership interest by noncontrolling interest owner	25.00%
Equity Investments [Member] | White Cliffs [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	10.00%	[1]
Equity Investments [Member] | Rendezvous [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	22.00%	[1]
Equity Investments [Member] | Mont Belvieu JV [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	25.00%	[1]
Equity Investments [Member] | Texas Express Pipeline LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	20.00%	[1]
Equity Investments [Member] | Texas Express Gathering LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	20.00%	[1]
Equity Investments [Member] | Front Range Pipeline LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	33.33%	[1]
Proportionate Consolidation [Member] | Non-Operated Marcellus Interest [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	33.75%	[2]
Proportionate Consolidation [Member] | Anadarko-Operated Marcellus Interest [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	33.75%	[2]
Proportionate Consolidation [Member] | Newcastle [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	50.00%	[2]
Proportionate Consolidation [Member] | Delaware Basin JV Gathering LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	50.00%	[2]
Proportionate Consolidation [Member] | Springfield Pipeline LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	50.10%	[2]
Full Consolidation [Member] | Chipeta Processing Limited Liability Company [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	75.00%	[3]
[1]	Investments in non-controlled entities over which the Partnership exercises significant influence are accounted for under the equity method. “Equity investment throughput” refers to the Partnership’s share of average throughput for these investments.
[2]	The Partnership proportionately consolidates its associated share of the assets, liabilities, revenues and expenses attributable to these assets.
[3]	The 25% interest in Chipeta Processing LLC (“Chipeta”) held by a third-party member is reflected within noncontrolling interest in the consolidated financial statements.

Description of Business and B30

Description of Business and Basis of Presentation - Additional Information (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2016USD ($)Mcf / d	Jun. 30, 2015USD ($)	[1]	Dec. 31, 2015USD ($)
Proceeds from property insurance claims	$ 2,944	$ 0
Other assets	13,481			$ 13,001	[2]
Long-term debt	2,932,004			2,690,651	[2]
New Accounting Standard Adjustment [Member] | Accounting Standards Update 2015-03 And 2015-15 [Member]
Other assets				(16,700)
Long-term debt				(16,700)
Delaware Basin Midstream Complex [Member]
Property insurance claim receivable	44,200			$ 49,000
Proceeds from insurance claims, total	5,500
Proceeds from business interruption claims	2,600
Proceeds from property insurance claims	$ 2,900
Delaware Basin Midstream Complex [Member] | Train II [Member]
Plant capacity | Mcf / d	100,000
Delaware Basin Midstream Complex [Member] | Train III [Member]
Plant capacity | Mcf / d	200,000
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.
[2]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.

Acquisitions and Divestitures -

Acquisitions and Divestitures - Acquisitions Table (Details) - USD ($) $ in Thousands		Mar. 14, 2016	Mar. 02, 2015		Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Deferred purchase price obligation - Anadarko, present value	[1]				$ 29,150		$ 188,674	[2]
Units issued					534,146
Revolving Credit Facility [Member]
Business Acquisition [Line Items]
Borrowings					$ 530,000
Delaware Basin JV Gathering LLC [Member]
Business Acquisition [Line Items]
Percentage acquired	[3]		100.00%
Delaware Basin JV Gathering LLC [Member] | Delaware Basin JV Gathering System [Member]
Business Acquisition [Line Items]
Percentage acquired			50.00%
Delaware Basin JV Gathering LLC [Member] | Deferred Purchase Price Obligation - Anadarko [Member] | Affiliates [Member]
Business Acquisition [Line Items]
Deferred purchase price obligation - Anadarko, present value			$ 174,276	[3]	29,150	$ 193,211	$ 188,674
Deferred purchase price obligation - Anadarko, future value			$ 282,807		$ 41,666
Springfield Pipeline LLC [Member]
Business Acquisition [Line Items]
Percentage acquired	[4]	100.00%
Acquisition price		$ 750,000
Springfield Pipeline LLC [Member] | Anadarko [Member]
Business Acquisition [Line Items]
Cash payment for acquisition		$ 712,500
Springfield Pipeline LLC [Member] | Common Units [Member]
Business Acquisition [Line Items]
Units issued	[4]	2,089,602
Springfield Pipeline LLC [Member] | Common Units [Member] | Anadarko [Member]
Business Acquisition [Line Items]
Units issued		1,253,761
Springfield Pipeline LLC [Member] | Common Units [Member] | Western Gas Equity Partners, LP [Member]
Business Acquisition [Line Items]
Units issued		835,841
Springfield Pipeline LLC [Member] | Series A Preferred Units [Member]
Business Acquisition [Line Items]
Units issued	[4]	14,030,611
Springfield Pipeline LLC [Member] | Springfield System [Member]
Business Acquisition [Line Items]
Percentage acquired		50.10%
Springfield Pipeline LLC [Member] | Revolving Credit Facility [Member]
Business Acquisition [Line Items]
Borrowings	[4]	$ 247,500
[1]	See Note 2.
[2]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.
[3]	The Partnership acquired Delaware Basin JV Gathering LLC (“DBJV”) from Anadarko. DBJV owns a 50% interest in a gathering system and related facilities. The DBJV gathering system and related facilities (the “DBJV system”) are located in the Delaware Basin in Loving, Ward, Winkler and Reeves Counties, Texas. The Partnership will make a cash payment on March 31, 2020, to Anadarko as consideration for the acquisition of DBJV. At the acquisition date, the Partnership estimated the future payment would be $282.8 million, the net present value of which was $174.3 million. For further information, including revisions to the estimated future payment, see DBJV acquisition—deferred purchase price obligation - Anadarko below.
[4]	The Partnership acquired Springfield Pipeline LLC (“Springfield”) from Anadarko for $750.0 million, consisting of $712.5 million in cash and the issuance of 1,253,761 of the Partnership’s common units. Springfield owns a 50.1% interest in an oil gathering system and a gas gathering system, such interest being referred to in this report as the “Springfield interest.” The Springfield oil and gas gathering systems (collectively, the “Springfield system”) are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. The Partnership financed the cash portion of the acquisition through: (i) borrowings of $247.5 million on the Partnership’s senior unsecured revolving credit facility (“RCF”), (ii) the issuance of 835,841 of the Partnership’s common units to WGP and (iii) the issuance of Series A Preferred units to private investors. See Note 4 for further information regarding the Series A Preferred units.

Acquisitions and Divestitures32

Acquisitions and Divestitures - Impact to Historical Consolidated Statements of Income Table (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015		Jun. 30, 2016	Jun. 30, 2015
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenues and other	$ 428,664	$ 465,993	[1]	$ 811,805	$ 902,999	[1]
Net income (loss)	$ 167,325	135,159	[1]	$ 286,408	(18,108)	[1]
Springfield Pipeline LLC [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenues and other		49,438			98,051
Net income (loss)		18,719			42,016
Springfield Pipeline LLC [Member] | Eliminations [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenues and other		(17)			(33)
Net income (loss)		0			0
Partnership Historical [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenues and other		416,572			804,981
Net income (loss)		$ 116,440			$ (60,124)
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.

Acquisitions and Divestitures33

Acquisitions and Divestitures - Impact of the Deferred Purchase Price Obligation - Anadarko Table (Details) - USD ($) $ in Thousands

3 Months Ended

6 Months Ended

12 Months Ended

Jun. 30, 2016

Mar. 31, 2016

Jun. 30, 2015

Jun. 30, 2016

Jun. 30, 2015

Dec. 31, 2015

Mar. 02, 2015

Property, Plant and Equipment [Line Items]

Deferred purchase price obligation - Anadarko, present value

[1]

$ 29,150

$ 29,150

$ 188,674

[2]

Affiliates [Member] | Deferred Purchase Price Obligation - Anadarko [Member]

Property, Plant and Equipment [Line Items]

Accretion expense

[3]

(15,461)

$ 4,190

(10,924)

$ 5,610

Affiliates [Member] | Delaware Basin JV Gathering LLC [Member] | Deferred Purchase Price Obligation - Anadarko [Member]

Property, Plant and Equipment [Line Items]

Deferred purchase price obligation - Anadarko, present value

29,150

$ 193,211

29,150

188,674

$ 174,276

[4]

Accretion expense

(15,461)

[5]

$ 4,537

[6]

(10,924)

$ 5,600

$ 14,398

[6]

Revision to Deferred purchase price obligation – Anadarko

[7]

(148,600)

Deferred purchase price obligation - Anadarko, future value

$ 41,666

$ 41,666

$ 282,807

[1]

See Note 2.

[2]

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

[3]

See Note 2 for a discussion of the accretion and net present value of the Deferred purchase price obligation - Anadarko.

[4]

The Partnership acquired Delaware Basin JV Gathering LLC (“DBJV”) from Anadarko. DBJV owns a 50% interest in a gathering system and related facilities. The DBJV gathering system and related facilities (the “DBJV system”) are located in the Delaware Basin in Loving, Ward, Winkler and Reeves Counties, Texas. The Partnership will make a cash payment on March 31, 2020, to Anadarko as consideration for the acquisition of DBJV. At the acquisition date, the Partnership estimated the future payment would be $282.8 million, the net present value of which was $174.3 million. For further information, including revisions to the estimated future payment, see DBJV acquisition—deferred purchase price obligation - Anadarko below.

[5]

Interest expense on the consolidated statements of operations includes financing-related accretion revisions of $15.5 million and $10.9 million for the three and six months ended June 30, 2016, respectively.

[6]

Accretion expense was recorded as a charge to Interest expense on the consolidated statements of operations.

[7]

Recorded as revisions within Common units on the consolidated balance sheets and consolidated statement of equity and partners’ capital.

Acquisitions and Divestitures34

Acquisitions and Divestitures - Additional Information (Details) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015		Mar. 02, 2015
Property, Plant and Equipment [Line Items]
Deferred purchase price obligation - Anadarko, present value	[1]	$ 29,150		$ 188,674	[2]
Delaware Basin JV Gathering LLC [Member] | Deferred Purchase Price Obligation - Anadarko [Member] | Affiliates [Member]
Property, Plant and Equipment [Line Items]
Deferred purchase price obligation - Anadarko, future value		41,666				$ 282,807
Deferred purchase price obligation - Anadarko, present value		$ 29,150	$ 193,211	$ 188,674		$ 174,276	[3]
Discount rate percentage		10.00%
Deferred purchase price obligation to Anadarko - future value change		$ 241,100
[1]	See Note 2.
[2]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.
[3]	The Partnership acquired Delaware Basin JV Gathering LLC (“DBJV”) from Anadarko. DBJV owns a 50% interest in a gathering system and related facilities. The DBJV gathering system and related facilities (the “DBJV system”) are located in the Delaware Basin in Loving, Ward, Winkler and Reeves Counties, Texas. The Partnership will make a cash payment on March 31, 2020, to Anadarko as consideration for the acquisition of DBJV. At the acquisition date, the Partnership estimated the future payment would be $282.8 million, the net present value of which was $174.3 million. For further information, including revisions to the estimated future payment, see DBJV acquisition—deferred purchase price obligation - Anadarko below.

Partnership Distributions - Cas

Partnership Distributions - Cash Distributions Table (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Jun. 30, 2016	[1]	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015
Distributions Made to Members or Limited Partners [Abstract]
Total quarterly distribution per unit	$ 0.830		$ 0.815	$ 0.800	$ 0.775	$ 0.750	$ 0.725
Total quarterly cash distribution	$ 162,827		$ 158,905	$ 152,588	$ 146,160	$ 139,736	$ 133,203
[1]	On July 20, 2016, the Board of Directors of the Partnership’s general partner declared a cash distribution to the Partnership’s unitholders of $0.830 per unit, or $162.8 million in aggregate, including incentive distributions, but excluding distributions on Class C units (see Class C unit distributions below) and Series A Preferred units (see Series A Preferred unit distributions below). The cash distribution is payable on August 12, 2016, to unitholders of record at the close of business on August 1, 2016.

Partnership Distributions - Add

Partnership Distributions - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Jun. 30, 2016
Distribution Made to Limited Partner [Line Items]
Partnership agreement day requirement of distribution of available cash				45 days
Class C Units [Member]
Distribution Made to Limited Partner [Line Items]
Discount rate percentage				6.00%
PIK Class C units		210,562	323,584
Units outstanding	11,946,008		11,411,862	11,946,008
Series A Preferred Units [Member]
Distribution Made to Limited Partner [Line Items]
Series A Preferred units quarterly distribution per unit				$ 0.68
Series A Preferred units quarterly cash distribution	$ 14.1	$ 1.9
Number of days in prorated period	77 days	18 days
Units outstanding	21,922,831	14,030,611	0	21,922,831
Series A Preferred Units [Member] | Option on Securities [Member]
Distribution Made to Limited Partner [Line Items]
Units outstanding	7,892,220			7,892,220

Equity and Partners' Capital -

Equity and Partners' Capital - Partnership Interests Table (Details) - shares		Mar. 14, 2016	Apr. 30, 2016	Jun. 30, 2016
Capital Unit [Line Items]
Balance				142,571,895
Units issued				534,146
Long-Term Incentive Plan award vestings				5,403
Balance				167,123,877
Option on Securities [Member] | Private Investor [Member]
Capital Unit [Line Items]
Units issued				7,892,220
Springfield Pipeline LLC [Member]
Capital Unit [Line Items]
Acquisition				16,120,213
Common Units [Member]
Capital Unit [Line Items]
Balance				128,576,965
Long-Term Incentive Plan award vestings				5,403
Balance				130,671,970
Common Units [Member] | Springfield Pipeline LLC [Member]
Capital Unit [Line Items]
Units issued	[1]	2,089,602
Acquisition				2,089,602
Class C Units [Member]
Capital Unit [Line Items]
Balance				11,411,862
Units issued				534,146
Balance				11,946,008
Series A Preferred Units [Member]
Capital Unit [Line Items]
Balance				0
Balance				21,922,831
Series A Preferred Units [Member] | Private Investor [Member]
Capital Unit [Line Items]
Units issued		14,030,611
Series A Preferred Units [Member] | Option on Securities [Member] | Private Investor [Member]
Capital Unit [Line Items]
Units issued			7,892,220	7,892,220
Series A Preferred Units [Member] | Springfield Pipeline LLC [Member]
Capital Unit [Line Items]
Units issued	[1]	14,030,611
Acquisition				14,030,611
General Partner [Member]
Capital Unit [Line Items]
Balance				2,583,068
Balance				2,583,068
[1]	The Partnership acquired Springfield Pipeline LLC (“Springfield”) from Anadarko for $750.0 million, consisting of $712.5 million in cash and the issuance of 1,253,761 of the Partnership’s common units. Springfield owns a 50.1% interest in an oil gathering system and a gas gathering system, such interest being referred to in this report as the “Springfield interest.” The Springfield oil and gas gathering systems (collectively, the “Springfield system”) are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. The Partnership financed the cash portion of the acquisition through: (i) borrowings of $247.5 million on the Partnership’s senior unsecured revolving credit facility (“RCF”), (ii) the issuance of 835,841 of the Partnership’s common units to WGP and (iii) the issuance of Series A Preferred units to private investors. See Note 4 for further information regarding the Series A Preferred units.

Equity and Partners' Capital 38

Equity and Partners' Capital - Calculation of Net Income (Loss) Per Unit Table (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015		Jun. 30, 2016	Jun. 30, 2015
Earnings Per Unit [Line Items]
Net income (loss) attributable to Western Gas Partners, LP		$ 164,521	$ 132,343	[1]	$ 280,581	$ (24,150)	[1]
Pre-acquisition net (income) loss allocated to Anadarko		0	(18,719)	[1]	(11,326)	(43,758)	[1]
General partner interest in net (income) loss	[2]	$ (58,381)	$ (45,971)	[1]	$ (113,781)	$ (83,148)	[1]
Net income (loss) per common unit – basic and diluted	[3],[4]	$ 0.55	$ 0.46	[1]	$ 0.86	$ (1.14)	[1]
Series A Preferred Units [Member]
Earnings Per Unit [Line Items]
Limited partners’ interest in net income (loss)	[2],[5]	$ 23,121	$ 0	[1]	$ 25,450	$ 0	[1]
Anti-dilutive units excluded from computation of earnings per unit		20,709	0		11,742	0
Common and Class C Units [Member]
Earnings Per Unit [Line Items]
Limited partners’ interest in net income (loss)	[2]	$ 83,019	$ 67,653	[1]	$ 130,024	$ (151,056)	[1]
Common Units [Member]
Earnings Per Unit [Line Items]
Limited partners’ interest in net income (loss)	[5]	$ 71,622	$ 59,119		$ 111,184	$ (146,139)
Weighted-average common units outstanding - basic and diluted		130,669	128,481		129,830	128,111
Class C Units [Member]
Earnings Per Unit [Line Items]
Limited partners’ interest in net income (loss)	[5]	$ 11,397	$ 8,534		$ 18,840	$ (4,917)
Anti-dilutive units excluded from computation of earnings per unit		11,849	11,023		11,719	10,981
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.
[2]	Represents net income (loss) earned on and subsequent to the date of acquisition of the Partnership assets (as defined in Note 1). See Note 4.
[3]	See Note 4 for the calculation of net income (loss) per common unit.
[4]	The impact of Class C units and the conversion of Series A Preferred units would be anti-dilutive.
[5]	Adjusted to reflect amortization of the beneficial conversion features.

Equity and Partners' Capital 39

Equity and Partners' Capital - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Mar. 14, 2016	Apr. 30, 2016	Nov. 30, 2014	Jun. 30, 2016	Jun. 30, 2015	[1]	Dec. 31, 2015	Dec. 31, 2014	Mar. 31, 2016	Aug. 31, 2014
Schedule Of Investments [Line Items]
Units issued				534,146
Beneficial conversion feature				$ 0
General partner units owned				2,583,068			2,583,068
Private Investor [Member] | Option on Securities [Member]
Schedule Of Investments [Line Items]
Units issued				7,892,220
Western Gas Equity Partners, LP [Member]
Schedule Of Investments [Line Items]
General partner units owned				2,583,068
General partner's interest				1.50%
Class C Units [Member]
Schedule Of Investments [Line Items]
Units issued				534,146
Price per unit			$ 68.72
Proceeds from the issuance of units			$ 750,000
Beneficial conversion feature								$ 34,800
Limited partner units owned				11,946,008			11,411,862
Class C Units [Member] | Other Subsidiaries Of Anadarko [Member]
Schedule Of Investments [Line Items]
Units issued			10,913,853
Limited partner units owned				11,946,008
Class C Units [Member] | Maximum [Member]
Schedule Of Investments [Line Items]
Redeemable option on units			$ 150,000
Series A Preferred Units [Member]
Schedule Of Investments [Line Items]
Price per unit	$ 32
Proceeds from the issuance of units	$ 440,000			$ 686,940	$ 0
Beneficial conversion feature				$ 21,700
Transaction fee	2.00%
Series A Preferred units, units issued upon conversion				1
Minimum common unit closing price for conversion				$ 48
Limited partner units owned				21,922,831			0		14,030,611
Series A Preferred Units [Member] | Option on Securities [Member]
Schedule Of Investments [Line Items]
Proceeds from the issuance of units		$ 246,900
Beneficial conversion feature				$ 71,700
Limited partner units owned				7,892,220
Series A Preferred Units [Member] | Private Investor [Member]
Schedule Of Investments [Line Items]
Units issued	14,030,611
Limited partner units owned				21,922,831
Limited partner ownership interest				13.10%
Series A Preferred Units [Member] | Private Investor [Member] | Option on Securities [Member]
Schedule Of Investments [Line Items]
Units issued		7,892,220		7,892,220
Series A Preferred Units [Member] | Change In Control [Member]
Schedule Of Investments [Line Items]
Redemption price per unit				$ 32.32
Common Units [Member]
Schedule Of Investments [Line Items]
Limited partner units owned				130,671,970			128,576,965
Common Units [Member] | Western Gas Equity Partners, LP [Member]
Schedule Of Investments [Line Items]
Limited partner units owned				50,132,046
Limited partner ownership interest				30.00%
Common Units [Member] | Other Subsidiaries Of Anadarko [Member]
Schedule Of Investments [Line Items]
Limited partner units owned				2,011,380
Common Units [Member] | Public [Member]
Schedule Of Investments [Line Items]
Limited partner units owned				78,528,544
Limited partner ownership interest				47.00%
Incentive Distribution Rights [Member] | Western Gas Equity Partners, LP [Member]
Schedule Of Investments [Line Items]
General partner's interest				100.00%
Common and Class C Units [Member] | Other Subsidiaries Of Anadarko [Member]
Schedule Of Investments [Line Items]
Limited partner ownership interest				8.40%
500 Million COP [Member]
Schedule Of Investments [Line Items]
Maximum aggregate principal of common units										$ 500,000
Average price per unit							$ 66.61
Net proceeds							$ 57,400
Underwriting discount and other offering expenses							800
Gross proceeds							58,200
Commissions paid							$ 600
500 Million COP [Member] | Common Units [Member]
Schedule Of Investments [Line Items]
Common units issued				0			873,525
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.

Transactions with Affiliates -

Transactions with Affiliates - Commodity Price Swap Agreements Table (Details) - Year 2016 [Member]	Jun. 30, 2016$ / MMBTU$ / bbl
Ethane [Member] | Minimum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	18.41
Ethane [Member] | Maximum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	23.11
Propane [Member] | Minimum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	47.08
Propane [Member] | Maximum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	52.90
Isobutane [Member] | Minimum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	62.09
Isobutane [Member] | Maximum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	73.89
Normal butane [Member] | Minimum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	54.62
Normal butane [Member] | Maximum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	64.93
Natural gasoline [Member] | Minimum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	72.88
Natural gasoline [Member] | Maximum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	81.68
Condensate [Member] | Minimum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	76.47
Condensate [Member] | Maximum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	81.68
Natural gas (per MMBtu) [Member] | Minimum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price | $ / MMBTU	4.87
Natural gas (per MMBtu) [Member] | Maximum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price | $ / MMBTU	5.96

Transactions with Affiliates 41

Transactions with Affiliates - Gains (Losses) on Commodity Price Swap Agreements Table (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements		$ 8,769	$ 18,921	$ 17,009	$ 40,156
Sales [Member]
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements	[1]	25,682	60,641	52,793	116,055
Sales [Member] | Natural Gas [Member]
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements	[1]	5,202	22,344	12,243	33,326
Sales [Member] | Natural Gas Liquids [Member]
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements	[1]	20,480	38,297	40,550	82,729
Purchases [Member]
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements	[2]	$ (16,913)	$ (41,720)	$ (35,784)	$ (75,899)
[1]	Reported in affiliate Natural gas and natural gas liquids sales in the consolidated statements of operations in the period in which the related sale is recorded.
[2]	Reported in Cost of product in the consolidated statements of operations in the period in which the related purchase is recorded.

Transactions with Affiliates 42

Transactions with Affiliates - Commodity Price Swap Agreements Extensions Tables (Details)		Dec. 08, 2015$ / MMBTU$ / bbl	Jun. 25, 2015$ / MMBTU$ / bbl
Year 2015 [Member] | DJ Basin Complex [Member] | Ethane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price			18.41
Commodity market price	[1]		1.96
Year 2015 [Member] | DJ Basin Complex [Member] | Propane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price			47.08
Commodity market price	[1]		13.10
Year 2015 [Member] | DJ Basin Complex [Member] | Isobutane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price			62.09
Commodity market price	[1]		19.75
Year 2015 [Member] | DJ Basin Complex [Member] | Normal butane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price			54.62
Commodity market price	[1]		18.99
Year 2015 [Member] | DJ Basin Complex [Member] | Natural gasoline [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price			72.88
Commodity market price	[1]		52.59
Year 2015 [Member] | DJ Basin Complex [Member] | Condensate [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price			76.47
Commodity market price	[1]		52.59
Year 2015 [Member] | DJ Basin Complex [Member] | Natural gas (per MMBtu) [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price | $ / MMBTU			5.96
Commodity market price | $ / MMBTU	[1]		2.75
Year 2015 [Member] | Hugoton System [Member] | Condensate [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price			78.61
Commodity market price	[1]		32.56
Year 2015 [Member] | Hugoton System [Member] | Natural gas (per MMBtu) [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price | $ / MMBTU			5.50
Commodity market price | $ / MMBTU	[1]		2.74
Year 2016 [Member] | DJ Basin Complex [Member] | Ethane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		18.41
Commodity market price	[2]	0.60
Year 2016 [Member] | DJ Basin Complex [Member] | Propane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		47.08
Commodity market price	[2]	10.98
Year 2016 [Member] | DJ Basin Complex [Member] | Isobutane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		62.09
Commodity market price	[2]	17.23
Year 2016 [Member] | DJ Basin Complex [Member] | Normal butane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		54.62
Commodity market price	[2]	16.86
Year 2016 [Member] | DJ Basin Complex [Member] | Natural gasoline [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		72.88
Commodity market price	[2]	26.15
Year 2016 [Member] | DJ Basin Complex [Member] | Condensate [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		76.47
Commodity market price	[2]	34.65
Year 2016 [Member] | DJ Basin Complex [Member] | Natural gas (per MMBtu) [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price | $ / MMBTU		5.96
Commodity market price | $ / MMBTU	[2]	2.11
Year 2016 [Member] | Hugoton System [Member] | Condensate [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		78.61
Commodity market price	[2]	18.81
Year 2016 [Member] | Hugoton System [Member] | Natural gas (per MMBtu) [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price | $ / MMBTU		5.50
Commodity market price | $ / MMBTU	[2]	2.12
[1]	Represents the New York Mercantile Exchange (“NYMEX”) forward strip price as of June 25, 2015, adjusted for product specification, location, basis and, in the case of NGLs, transportation and fractionation costs.
[2]	Represents the NYMEX forward strip price as of December 8, 2015, adjusted for product specification, location, basis and, in the case of NGLs, transportation and fractionation costs.

Transactions with Affiliates 43

Transactions with Affiliates - Equipment Purchases and Sales Table (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Related Party Transaction [Line Items]
Partners’ capital adjustment	$ 354	$ 4,540	[1]
Affiliates [Member] | Purchases [Member]
Related Party Transaction [Line Items]
Cash consideration - purchases	2,699	9,056
Net carrying value	2,328	4,182
Partners’ capital adjustment	371	4,874
Affiliates [Member] | Sales [Member]
Related Party Transaction [Line Items]
Cash consideration - sales	613	700
Net carrying value	596	366
Partners’ capital adjustment	$ (17)	$ (334)
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.

Transactions with Affiliates 44

Transactions with Affiliates - Summary of Affiliate Transactions Table (Details) - USD ($) $ in Thousands		Mar. 14, 2016	Jun. 30, 2016	Jun. 30, 2015		Jun. 30, 2016		Jun. 30, 2015
Related Party Transaction [Line Items]
Revenues and other			$ 428,664	$ 465,993	[1]	$ 811,805		$ 902,999	[1]
Equity income, net – affiliates	[2]		19,693	18,941	[1]	36,507		37,161	[1]
Cost of product	[3]		104,849	147,216	[1]	181,316		286,624	[1]
Operation and maintenance	[3]		75,173	77,837	[1]	151,386		154,022	[1]
General and administrative	[3]		10,883	9,408	[1]	22,160		20,489	[1]
Operating expenses			272,691	314,221	[1]	518,611		891,774	[1]
Interest income	[4]		4,225	4,225	[1]	8,450		8,450	[1]
Interest expense	[5]		12,883	27,604	[1]	44,919		50,564	[1]
Proceeds from the issuance of common units, net of offering expenses						25,000		57,376	[1]
Distributions to unitholders	[6]					313,380		259,247	[1]
Above-market component of swap extensions with Anadarko			9,552	0		$ 16,365	[6]	0	[1],[6]
Units issued						534,146
Springfield Pipeline LLC [Member]
Related Party Transaction [Line Items]
Revenues and other				49,438				98,051
Springfield Pipeline LLC [Member] | Common Units [Member]
Related Party Transaction [Line Items]
Units issued	[7]	2,089,602
Affiliates [Member]
Related Party Transaction [Line Items]
Revenues and other	[2]		302,405	321,411	[1]	$ 574,989		628,339	[1]
Cost of product	[2]		22,145	53,062		46,725		96,957
Operation and maintenance	[8]		17,661	19,854		35,636		36,671
General and administrative	[9]		9,169	8,060		18,121		16,195
Operating expenses			48,975	80,976		100,482		149,823
Interest expense	[10]		(15,461)	4,190		(10,924)		5,610
Proceeds from the issuance of common units, net of offering expenses	[11]		0	0		25,000		0
Distributions to unitholders	[12]		$ 94,909	$ 76,353		$ 184,678		$ 148,048
Western Gas Equity Partners, LP [Member] | Springfield Pipeline LLC [Member] | Common Units [Member]
Related Party Transaction [Line Items]
Units issued		835,841
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.
[2]	Represents amounts earned or incurred on and subsequent to the date of acquisition of the Partnership assets, as well as amounts earned or incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets, recognized under gathering, treating or processing agreements, and purchase and sale agreements.
[3]	Cost of product includes product purchases from Anadarko (as defined in Note 1) of $22.1 million and $46.7 million for the three and six months ended June 30, 2016, respectively, and $53.1 million and $97.0 million for the three and six months ended June 30, 2015, respectively. Operation and maintenance includes charges from Anadarko of $17.7 million and $35.6 million for the three and six months ended June 30, 2016, respectively, and $19.9 million and $36.7 million for the three and six months ended June 30, 2015, respectively. General and administrative includes charges from Anadarko of $9.2 million and $18.1 million for the three and six months ended June 30, 2016, respectively, and $8.1 million and $16.2 million for the three and six months ended June 30, 2015, respectively. See Note 5.
[4]	Represents interest income recognized on the note receivable from Anadarko.
[5]	Includes affiliate (as defined in Note 1) amounts of $(15.5) million and $(10.9) million for the three and six months ended June 30, 2016, respectively, and $4.2 million and $5.6 million for the three and six months ended June 30, 2015, respectively. See Note 2 and Note 9.
[6]	See Note 5.
[7]	The Partnership acquired Springfield Pipeline LLC (“Springfield”) from Anadarko for $750.0 million, consisting of $712.5 million in cash and the issuance of 1,253,761 of the Partnership’s common units. Springfield owns a 50.1% interest in an oil gathering system and a gas gathering system, such interest being referred to in this report as the “Springfield interest.” The Springfield oil and gas gathering systems (collectively, the “Springfield system”) are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. The Partnership financed the cash portion of the acquisition through: (i) borrowings of $247.5 million on the Partnership’s senior unsecured revolving credit facility (“RCF”), (ii) the issuance of 835,841 of the Partnership’s common units to WGP and (iii) the issuance of Series A Preferred units to private investors. See Note 4 for further information regarding the Series A Preferred units.
[8]	Represents expenses incurred on and subsequent to the date of the acquisition of the Partnership assets, as well as expenses incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets.
[9]	Represents general and administrative expense incurred on and subsequent to the date of the Partnership’s acquisition of the Partnership assets, as well as a management services fee for reimbursement of expenses incurred by Anadarko for periods prior to the acquisition of the Partnership assets by the Partnership. These amounts include equity-based compensation expense allocated to the Partnership by Anadarko (see WES LTIP and WGP LTIP and Anadarko Incentive Plans within this Note 5).
[10]	For the three and six months ended June 30, 2016, includes accretion revisions to the Deferred purchase price obligation - Anadarko (see Note 2 and Note 9).
[11]	Represents proceeds from the issuance of 835,841 common units to WGP as partial funding for the acquisition of Springfield (see Note 2).
[12]	Represents distributions paid under the partnership agreement (see Note 3 and Note 4).

Transactions with Affiliates 45

Transactions with Affiliates - Additional Information (Details) - USD ($)		1 Months Ended	3 Months Ended		6 Months Ended
		May 31, 2008	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Related Party Transaction [Line Items]
Note receivable - Anadarko			$ 260,000,000		$ 260,000,000		$ 260,000,000	[1]
Above-market component of swap extensions with Anadarko	[2]				16,365,000
Contributions of equity-based compensation from Anadarko					$ 2,053,000
Western Gas Partners Long Term Incentive Plan [Member]
Related Party Transaction [Line Items]
Units vesting period					3 years
Equity-based compensation expense			100,000	$ 100,000	$ 200,000	$ 200,000
Western Gas Equity Partners Long Term Incentive Plan [Member] | Anadarko Incentive Plans [Member]
Related Party Transaction [Line Items]
Equity-based compensation expense			$ 1,100,000	$ 1,000,000	2,400,000	$ 2,000,000
Contributions of equity-based compensation from Anadarko					$ 2,100,000
Natural Gas [Member] | Gathering, Treating and Transportation [Member]
Related Party Transaction [Line Items]
Affiliate throughput percent			39.00%	56.00%	38.00%	56.00%
Natural Gas [Member] | Processing [Member]
Related Party Transaction [Line Items]
Affiliate throughput percent			55.00%	52.00%	58.00%	52.00%
Crude Oil and NGL [Member] | Gathering, Treating and Transportation [Member]
Related Party Transaction [Line Items]
Affiliate throughput percent			64.00%	100.00%	64.00%	100.00%
Affiliates [Member]
Related Party Transaction [Line Items]
Note receivable - Anadarko		$ 260,000,000
Note receivable, due date		May 14, 2038
Fixed annual rate for note receivable bearing interest		6.50%
Affiliates [Member] | Level 2 Inputs [Member] | Market Approach Valuation Technique [Member]
Related Party Transaction [Line Items]
Fair value of the note receivable			$ 301,500,000		$ 301,500,000		$ 252,300,000
Independent Director [Member] | Western Gas Partners Long Term Incentive Plan [Member]
Related Party Transaction [Line Items]
Units vesting period					1 year
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.
[2]	See Note 5.

Property, Plant and Equipment -

Property, Plant and Equipment - Historical Cost Table (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 6,818,174	$ 6,556,778	[1]
Accumulated depreciation	1,816,030	1,697,999	[1]
Net property, plant and equipment	5,002,144	4,858,779	[1]
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	3,946	3,744
Gathering Systems [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 6,409,489	6,061,004
Gathering Systems [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Gathering Systems [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	47 years
Pipelines and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 135,319	136,290
Pipelines and Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	15 years
Pipelines and Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	45 years
Assets Under Construction [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 239,617	329,887
Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 29,803	$ 25,853
Other [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Other [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	40 years
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.

Property, Plant and Equipment47

Property, Plant and Equipment - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	[1]	Jun. 30, 2016	Jun. 30, 2015	[1]
Property, Plant and Equipment [Line Items]
Impairments	$ 2,403	$ 1,620		$ 8,921	$ 274,244
Newcastle System [Member]
Property, Plant and Equipment [Line Items]
Impairments				6,100
Newcastle System [Member] | Fair Value Measurements Nonrecurring [Member] | Level 3 Inputs [Member] | Income Approach Valuation Technique [Member]
Property, Plant and Equipment [Line Items]
Estimated fair value	$ 3,100			3,100
Equipment [Member]
Property, Plant and Equipment [Line Items]
Impairments				$ 2,400
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.

Equity Investments - Equity Inv

Equity Investments - Equity Investments Table (Details) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	[3]	Jun. 30, 2016		Jun. 30, 2015	[3]
Schedule of Equity Method Investments [Line Items]
Balance	[1]				$ 618,887
Investment earnings (loss), net of amortization	[2]	$ 19,693	$ 18,941		36,507		$ 37,161
Contributions					(139)		6,770
Distributions					(38,519)		(39,034)
Distributions in excess of cumulative earnings					(10,611)	[4]	$ (8,538)
Balance		606,125			606,125
Fort Union [Member]
Schedule of Equity Method Investments [Line Items]
Balance					17,122
Investment earnings (loss), net of amortization					(1,360)
Contributions					0
Distributions					0
Distributions in excess of cumulative earnings	[4]				(3,354)
Balance		12,408			12,408
White Cliffs [Member]
Schedule of Equity Method Investments [Line Items]
Balance					50,439
Investment earnings (loss), net of amortization					7,164
Contributions					441
Distributions					(6,873)
Distributions in excess of cumulative earnings	[4]				(2,100)
Balance		49,071			49,071
Rendezvous [Member]
Schedule of Equity Method Investments [Line Items]
Balance					50,913
Investment earnings (loss), net of amortization					949
Contributions					0
Distributions					(1,364)
Distributions in excess of cumulative earnings	[4]				(1,541)
Balance		48,957			48,957
Mont Belvieu JV [Member]
Schedule of Equity Method Investments [Line Items]
Balance					117,089
Investment earnings (loss), net of amortization					12,686
Contributions					0
Distributions					(12,303)
Distributions in excess of cumulative earnings	[4]				(172)
Balance		117,300			117,300
Texas Express Gathering LLC [Member]
Schedule of Equity Method Investments [Line Items]
Balance					16,283
Investment earnings (loss), net of amortization					343
Contributions					0
Distributions					(354)
Distributions in excess of cumulative earnings	[4]				(188)
Balance		16,084			16,084
Texas Express Pipeline LLC [Member]
Schedule of Equity Method Investments [Line Items]
Balance					194,803
Investment earnings (loss), net of amortization					7,766
Contributions					(580)
Distributions					(7,892)
Distributions in excess of cumulative earnings	[4]				(2,918)
Balance		191,179			191,179
Front Range Pipeline LLC [Member]
Schedule of Equity Method Investments [Line Items]
Balance					172,238
Investment earnings (loss), net of amortization					8,959
Contributions					0
Distributions					(9,733)
Distributions in excess of cumulative earnings	[4]				(338)
Balance		$ 171,126			$ 171,126
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.
[2]	Represents amounts earned or incurred on and subsequent to the date of acquisition of the Partnership assets, as well as amounts earned or incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets, recognized under gathering, treating or processing agreements, and purchase and sale agreements.
[3]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.
[4]	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.

Equity Investments - Additional

Equity Investments - Additional Information (Details) - Fort Union [Member] $ in Millions	6 Months Ended
	Jun. 30, 2016USD ($)
Schedule of Equity Method Investments [Line Items]
Equity investment impairment loss	$ 3
Equity Investments [Member]
Schedule of Equity Method Investments [Line Items]
Percentage ownership interest	14.81%	[1]
[1]	Investments in non-controlled entities over which the Partnership exercises significant influence are accounted for under the equity method. “Equity investment throughput” refers to the Partnership’s share of average throughput for these investments.

Components of Working Capital -

Components of Working Capital - Accounts Receivable, Net Table (Details) - USD ($) $ in Thousands		Jun. 30, 2016	Dec. 31, 2015
Receivables [Abstract]
Trade receivables, net		$ 177,507	$ 143,557
Other receivables, net		44,288	49,772
Total accounts receivable, net	[1]	$ 221,795	$ 193,329	[2]
[1]	Accounts receivable, net includes amounts receivable from affiliates (as defined in Note 1) of $81.3 million and $42.7 million as of June 30, 2016, and December 31, 2015, respectively. Accounts receivable, net as of June 30, 2016, and December 31, 2015, also includes an insurance claim receivable related to an incident at the DBM complex. See Note 1.
[2]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.

Components of Working Capital51

Components of Working Capital - Other Current Assets Table (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Other Current Assets [Line Items]
Natural gas liquids inventory	$ 4,032	$ 2,403
Imbalance receivables	1,359	2,122
Prepaid insurance	300	2,296
Other	0	1,034
Total other current assets	$ 5,691	$ 7,855	[1]
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.

Components of Working Capital52

Components of Working Capital - Accrued Liabilities Table (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Accrued Liabilities [Line Items]
Accrued interest expense	$ 26,200	$ 26,194
Short-term asset retirement obligations	2,713	3,677
Short-term remediation and reclamation obligations	1,136	1,136
Income taxes payable	1,127	770
Total accrued liabilities	130,018	119,019	[1]
Accrued Capital Expenditures [Member]
Accrued Liabilities [Line Items]
Other accrued liabilities	70,725	61,454
Accrued Plant Purchases [Member]
Accrued Liabilities [Line Items]
Other accrued liabilities	27,149	16,425
Other Accrued Liabilities [Member]
Accrued Liabilities [Line Items]
Other accrued liabilities	$ 968	$ 9,363
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.

Debt and Interest Expense - Deb

Debt and Interest Expense - Debt Outstanding Table (Details) - USD ($)		Jun. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Total long-term debt principal		$ 2,960,000,000	$ 2,720,000,000
Carrying value		2,932,004,000	2,690,651,000	[1]
Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[2]	2,940,187,000	2,492,466,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Principal		540,000,000	300,000,000
Carrying value		540,000,000	300,000,000
Revolving Credit Facility [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[2]	540,000,000	300,000,000
Senior Notes [Member] | 5.375% Senior Notes due 2021 [Member]
Debt Instrument [Line Items]
Principal		500,000,000	500,000,000
Carrying value		494,215,000	493,711,000
Senior Notes [Member] | 5.375% Senior Notes due 2021 [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[2]	529,064,000	513,645,000
Senior Notes [Member] | 4.000% Senior Notes due 2022 [Member]
Debt Instrument [Line Items]
Principal		670,000,000	670,000,000
Carrying value		668,532,000	668,432,000
Senior Notes [Member] | 4.000% Senior Notes due 2022 [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[2]	658,273,000	595,744,000
Senior Notes [Member] | 2.600% Senior Notes due 2018 [Member]
Debt Instrument [Line Items]
Principal		350,000,000	350,000,000
Carrying value		348,946,000	348,706,000
Senior Notes [Member] | 2.600% Senior Notes due 2018 [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[2]	348,908,000	339,293,000
Senior Notes [Member] | 5.450% Senior Notes due 2044 [Member]
Debt Instrument [Line Items]
Principal		400,000,000	400,000,000
Carrying value		389,783,000	389,707,000
Senior Notes [Member] | 5.450% Senior Notes due 2044 [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[2]	384,252,000	321,499,000
Senior Notes [Member] | 3.950% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Principal		500,000,000	500,000,000
Carrying value		490,528,000	490,095,000
Senior Notes [Member] | 3.950% Senior Notes due 2025 [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[2]	$ 479,690,000	$ 422,285,000
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.
[2]	Fair value is measured using the market approach and Level 2 inputs.

Debt and Interest Expense - D54

Debt and Interest Expense - Debt Activity Table (Details) - USD ($) $ in Thousands		1 Months Ended	6 Months Ended
		Apr. 30, 2016	Jun. 30, 2016
Debt Instrument [Line Items]
Beginning balance	[1]		$ 2,690,651
Other			1,353
Ending balance			2,932,004
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Beginning balance			300,000
RCF Borrowings			530,000
Repayments of RCF borrowings		$ (250,000)	(290,000)
Ending balance			$ 540,000
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.

Debt and Interest Expense - Int

Debt and Interest Expense - Interest Expense Table (Details) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015		Jun. 30, 2016	Jun. 30, 2015
Debt Instrument [Line Items]
Interest expense	[1]	$ 12,883	$ 27,604	[2]	$ 44,919	$ 50,564	[2]
Third Parties [Member]
Debt Instrument [Line Items]
Long-term debt		28,281	24,733		56,099	48,075
Amortization of debt issuance costs and commitment fees		1,545	1,374		3,075	2,666
Capitalized interest		(1,482)	(2,693)		(3,331)	(5,787)
Interest expense		28,344	23,414		55,843	44,954
Affiliates [Member]
Debt Instrument [Line Items]
Interest expense	[3]	(15,461)	4,190		(10,924)	5,610
Affiliates [Member] | Deferred Purchase Price Obligation - Anadarko [Member]
Debt Instrument [Line Items]
Deferred purchase price obligation - Anadarko	[4]	$ (15,461)	$ 4,190		$ (10,924)	$ 5,610
[1]	Includes affiliate (as defined in Note 1) amounts of $(15.5) million and $(10.9) million for the three and six months ended June 30, 2016, respectively, and $4.2 million and $5.6 million for the three and six months ended June 30, 2015, respectively. See Note 2 and Note 9.
[2]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.
[3]	For the three and six months ended June 30, 2016, includes accretion revisions to the Deferred purchase price obligation - Anadarko (see Note 2 and Note 9).
[4]	See Note 2 for a discussion of the accretion and net present value of the Deferred purchase price obligation - Anadarko.

Debt and Interest Expense - Add

Debt and Interest Expense - Additional Information (Details) - USD ($)	Jul. 12, 2016	Mar. 14, 2016	Apr. 30, 2016	Jun. 30, 2016	Jun. 30, 2015		Dec. 31, 2015
Treasury Lock [Member]
Debt Instrument [Line Items]
Realized loss on terminated U.S. Treasury rate lock agreement				$ 200,000
Series A Preferred Units [Member]
Debt Instrument [Line Items]
Proceeds from the issuance of units		$ 440,000,000		686,940,000	$ 0	[1]
Series A Preferred Units [Member] | Option on Securities [Member]
Debt Instrument [Line Items]
Proceeds from the issuance of units			$ 246,900,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Principal				$ 540,000,000			$ 300,000,000
Facility, interest rate at period end				1.77%	1.49%
Facility, fee rate				0.20%	0.20%
Facility, outstanding borrowings				$ 540,000,000
Outstanding letters of credit				4,900,000
Facility, available borrowing capacity				$ 655,100,000
Facility, expiration date				Feb. 26, 2019
Repayments of RCF borrowings			$ (250,000,000)	$ (290,000,000)
Senior Notes [Member] | 5.375% Senior Notes due 2021 [Member]
Debt Instrument [Line Items]
Fixed interest rate				5.375%
Debt instrument, maturity date				Jun. 1, 2021
Principal				$ 500,000,000			500,000,000
Senior Notes [Member] | 4.000% Senior Notes due 2022 [Member]
Debt Instrument [Line Items]
Fixed interest rate				4.00%
Debt instrument, maturity date				Jul. 1, 2022
Principal				$ 670,000,000			670,000,000
Senior Notes [Member] | 2.600% Senior Notes due 2018 [Member]
Debt Instrument [Line Items]
Fixed interest rate				2.60%
Debt instrument, maturity date				Aug. 15, 2018
Principal				$ 350,000,000			350,000,000
Senior Notes [Member] | 5.450% Senior Notes due 2044 [Member]
Debt Instrument [Line Items]
Fixed interest rate				5.45%
Debt instrument, maturity date				Apr. 1, 2044
Principal				$ 400,000,000			400,000,000
Senior Notes [Member] | 3.950% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Fixed interest rate				3.95%
Debt instrument, maturity date				Jun. 1, 2025
Principal				$ 500,000,000			$ 500,000,000
Senior Notes [Member] | 4.650% Senior Notes due 2026 [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Fixed interest rate	4.65%
Debt instrument, maturity date	Jul. 1, 2026
Principal	$ 500,000,000
Offering percent	99.796%
Underwriting discount	$ 3,100,000
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield interest. See Note 1 and Note 2.

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Committed capital	$ 38.3		$ 38.3
Rent expense associated with office, warehouse and equipment leases	$ 8.4	$ 8.5	$ 17.3	$ 16.5