Western Midstream Partners (WES) 10-Q 4 May 16 2016 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2016	May. 02, 2016
Document And Entity Information [Abstract]
Trading Symbol	WGP
Entity Registrant Name	Western Gas Equity Partners, LP
Entity Central Index Key	1,423,902
Document Type	10-Q
Document Period End Date	Mar. 31, 2016
Amendment Flag	false
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Units Outstanding		218,919,380

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Revenues and Other
Total revenues and other		$ 383,141	$ 437,006	[1]
Equity income, net	[2],[3],[4]	16,814	18,220	[1]
Operating expenses
Cost of product	[5]	76,467	139,408	[1]
Operation and maintenance	[5]	76,213	76,185	[1]
General and administrative	[5]	12,515	11,916	[1]
Property and other taxes		10,350	9,280	[1]
Depreciation and amortization		65,095	68,975	[1]
Impairments		6,518	272,624	[1]
Total operating expenses		247,158	578,388	[1]
Gain (loss) on divestiture and other, net		(632)	(6)	[1]
Operating income (loss)		152,165	(123,168)	[1]
Interest income – affiliates	[6]	4,225	4,225	[1]
Interest expense	[7]	(32,139)	(22,962)	[1]
Other income (expense), net		141	80	[1]
Income (loss) before income taxes		124,392	(141,825)	[1]
Income tax (benefit) expense		6,633	12,270	[1]
Net income (loss)		117,759	(154,095)	[1]
Net income (loss) attributable to noncontrolling interests		35,943	(137,723)	[1]
Net income (loss) attributable to Western Gas Equity Partners, LP		81,816	(16,372)	[1]
Limited partners' interest in net income (loss):
Pre-acquisition net (income) loss allocated to Anadarko		(11,326)	(25,039)	[1]
Limited partners' interest in net income (loss)	[8]	70,490	(41,411)	[1]
Affiliates [Member]
Revenues and Other
Gathering, processing and transportation		187,718	188,018	[1]
Natural gas and natural gas liquids sales		84,866	118,740	[1]
Other		0	170	[1]
Total revenues and other	[4]	272,584	306,928	[1]
Operating expenses
Cost of product	[4]	24,580	43,895
Operation and maintenance	[9]	17,975	16,817
General and administrative	[10]	9,150	8,335
Total operating expenses		51,705	69,047
Interest expense	[11]	(4,537)	(1,422)
Third Parties [Member]
Revenues and Other
Gathering, processing and transportation		106,286	82,250	[1]
Natural gas and natural gas liquids sales		3,690	46,932	[1]
Other		581	896	[1]
Total revenues and other		110,557	130,078	[1]
Operating expenses
Interest expense		$ (27,602)	$ (21,540)
Limited Partner [Member]
Limited partners' interest in net income (loss):
Net income (loss) per common unit - basic and diluted		$ 0.32	$ (0.19)	[1]
Weighted-average common units outstanding - basic and diluted		218,919	218,910	[1]
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.
[2]	Income earned from equity investments is classified as affiliate. See Note 1.
[3]	Income earned on, distributions from and contributions to equity investments are classified as affiliate. See Note 1.
[4]	Represents amounts earned or incurred on and subsequent to the date of acquisition of WES assets, as well as amounts earned or incurred by Anadarko on a historical basis related to WES assets prior to the acquisition of such assets by WES, recognized under gathering, treating or processing agreements, and purchase and sale agreements.
[5]	Cost of product includes product purchases from Anadarko (as defined in Note 1) of $24.6 million and $43.9 million for the three months ended March 31, 2016 and 2015, respectively. Operation and maintenance includes charges from Anadarko of $18.0 million and $16.8 million for the three months ended March 31, 2016 and 2015, respectively. General and administrative includes charges from Anadarko of $9.2 million and $8.3 million for the three months ended March 31, 2016 and 2015, respectively. See Note 5.
[6]	Represents interest income recognized on the note receivable from Anadarko.
[7]	Includes affiliate (as defined in Note 1) interest expense of $4.5 million and $1.4 million for the three months ended March 31, 2016 and 2015, respectively. See Note 2 and Note 9.
[8]	Represents net income (loss) earned on and subsequent to the date of acquisition of WES assets (as defined in Note 1). See Note 4.
[9]	Represents expenses incurred on and subsequent to the date of the acquisition of WES assets, as well as expenses incurred by Anadarko on a historical basis related to WES assets prior to the acquisition of such assets by WES.
[10]	Represents general and administrative expense incurred on and subsequent to the date of WES’s acquisition of WES assets, as well as a management services fee for reimbursement of expenses incurred by Anadarko for periods prior to the acquisition of WES assets by WES. These amounts include equity-based compensation expense allocated to WES and WGP by Anadarko (see WES LTIP and WGP LTIP and Anadarko Incentive Plans within this Note 5) and amounts charged by Anadarko under the WGP omnibus agreement.
[11]	For the three months ended March 31, 2016 and 2015, includes WES’s accretion expense recognized on the Deferred purchase price obligation - Anadarko for the acquisition of DBJV (see Note 2 and Note 9) and for the three months ended March 31, 2015, includes interest expense recognized on the WGP WCF (see Note 9).

Consolidated Statements of Inc3

Consolidated Statements of Income (Parenthetical) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Cost of product	[1]	$ 76,467	$ 139,408	[2]
Operation and maintenance	[1]	76,213	76,185	[2]
General and administrative	[1]	12,515	11,916	[2]
Interest expense	[3]	32,139	22,962	[2]
Affiliates [Member]
Cost of product	[4]	24,580	43,895
Operation and maintenance	[5]	17,975	16,817
General and administrative	[6]	9,150	8,335
Interest expense	[7]	$ 4,537	$ 1,422
[1]	Cost of product includes product purchases from Anadarko (as defined in Note 1) of $24.6 million and $43.9 million for the three months ended March 31, 2016 and 2015, respectively. Operation and maintenance includes charges from Anadarko of $18.0 million and $16.8 million for the three months ended March 31, 2016 and 2015, respectively. General and administrative includes charges from Anadarko of $9.2 million and $8.3 million for the three months ended March 31, 2016 and 2015, respectively. See Note 5.
[2]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.
[3]	Includes affiliate (as defined in Note 1) interest expense of $4.5 million and $1.4 million for the three months ended March 31, 2016 and 2015, respectively. See Note 2 and Note 9.
[4]	Represents amounts earned or incurred on and subsequent to the date of acquisition of WES assets, as well as amounts earned or incurred by Anadarko on a historical basis related to WES assets prior to the acquisition of such assets by WES, recognized under gathering, treating or processing agreements, and purchase and sale agreements.
[5]	Represents expenses incurred on and subsequent to the date of the acquisition of WES assets, as well as expenses incurred by Anadarko on a historical basis related to WES assets prior to the acquisition of such assets by WES.
[6]	Represents general and administrative expense incurred on and subsequent to the date of WES’s acquisition of WES assets, as well as a management services fee for reimbursement of expenses incurred by Anadarko for periods prior to the acquisition of WES assets by WES. These amounts include equity-based compensation expense allocated to WES and WGP by Anadarko (see WES LTIP and WGP LTIP and Anadarko Incentive Plans within this Note 5) and amounts charged by Anadarko under the WGP omnibus agreement.
[7]	For the three months ended March 31, 2016 and 2015, includes WES’s accretion expense recognized on the Deferred purchase price obligation - Anadarko for the acquisition of DBJV (see Note 2 and Note 9) and for the three months ended March 31, 2015, includes interest expense recognized on the WGP WCF (see Note 9).

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Mar. 31, 2016	Dec. 31, 2015	[1]
Current assets
Cash and cash equivalents		$ 111,456	$ 99,694
Accounts receivable, net	[2]	179,601	193,113
Other current assets		4,064	8,557
Total current assets		295,121	301,364
Note receivable - Anadarko		260,000	260,000
Property, plant and equipment
Cost		6,700,809	6,556,778
Less accumulated depreciation		1,760,590	1,697,999
Net property, plant and equipment		4,940,219	4,858,779
Goodwill		419,186	419,186
Other intangible assets		825,020	832,127
Equity investments		610,588	618,887
Other assets		15,549	13,001
Total assets		7,365,683	7,303,344
Current liabilities
Accounts and imbalance payables		103,754	98,661
Accrued ad valorem taxes		27,876	17,808
Accrued liabilities		128,380	119,096
Total current liabilities		260,010	235,565
Long-term debt		3,049,325	2,690,651
Deferred income taxes		5,906	139,704
Asset retirement obligations and other		132,126	128,652
Deferred purchase price obligation - Anadarko	[3]	193,211	188,674
Total long-term liabilities		3,380,568	3,147,681
Total liabilities		3,640,578	3,383,246
Equity and partners' capital
Common units (218,919,380 units issued and outstanding at March 31, 2016, and December 31, 2015)		876,876	1,060,842
Net investment by Anadarko		0	430,598
Total partners' capital		876,876	1,491,440
Noncontrolling interests		2,848,229	2,428,658
Total equity and partners' capital		3,725,105	3,920,098
Total liabilities, equity and partners' capital		$ 7,365,683	$ 7,303,344
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.
[2]	Accounts receivable, net includes amounts receivable from affiliates (as defined in Note 1) of $53.6 million and $42.5 million as of March 31, 2016, and December 31, 2015, respectively. Accounts receivable, net as of March 31, 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.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands		Mar. 31, 2016	Dec. 31, 2015
Common units issued		218,919,380	218,919,380
Units outstanding		218,919,380	218,919,380
Accounts receivable, net	[1]	$ 179,601	$ 193,113	[2]
Affiliates [Member]
Accounts receivable, net		$ 53,600	$ 42,500
[1]	Accounts receivable, net includes amounts receivable from affiliates (as defined in Note 1) of $53.6 million and $42.5 million as of March 31, 2016, and December 31, 2015, respectively. Accounts receivable, net as of March 31, 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 system. See Note 1 and Note 2.

Consolidated Statement of Equit

Consolidated Statement of Equity and Partners' Capital - 3 months ended Mar. 31, 2016 - USD ($) $ in Thousands		Total	Western Gas Partners, LP [Member]	Chipeta Processing Limited Liability Company [Member]	Net Investment by Anadarko [Member]	Common Units [Member]	Noncontrolling Interests [Member]	Noncontrolling Interests [Member]Western Gas Partners, LP [Member]	Noncontrolling Interests [Member]Chipeta Processing Limited Liability Company [Member]
Balance at Dec. 31, 2015	[1]	$ 3,920,098			$ 430,598	$ 1,060,842	$ 2,428,658
Net income (loss)		117,759			11,326	70,490	35,943
Above-market component of swap extensions with Anadarko	[2]	6,813				6,813
WES equity transactions, net	[3]	0				(10,714)	10,714
WES issuance of Series A Preferred units, net of offering expenses		440,000					440,000
Distributions to noncontrolling interest owners			$ (63,425)	$ (3,838)				$ (63,425)	$ (3,838)
Distributions to WGP unitholders		(88,389)				(88,389)
Acquisitions from affiliates		(712,500)			(549,692)	(162,808)
Contributions of equity-based compensation to WES by Anadarko		1,051				1,051
Net pre-acquisition contributions from (distributions to) Anadarko		(27,632)			(27,632)
Net distributions to Anadarko of other assets		(714)				(714)
Elimination of net deferred tax liabilities		135,400			135,400
Other		482				305	177
Balance at Mar. 31, 2016		$ 3,725,105			$ 0	$ 876,876	$ 2,848,229
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.
[2]	See Note 5.
[3]	Includes the impact of WES’s (as defined in Note 1) equity offerings as described in Note 4. The $10.7 million decrease to partners’ capital, together with net income (loss) attributable to Western Gas Equity Partners, LP, totaled $71.1 million for the three months ended March 31, 2016.

Consolidated Statement of Equi7

Consolidated Statement of Equity and Partners' Capital (Parenthetical) $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)
WES equity transactions, net	$ 0	[1]
Combined change in Partners' Capital from WES equity transactions, net and net income (loss) attributable to Western Gas Equity Partners, LP	71,100
Common Units [Member]
WES equity transactions, net	$ (10,714)	[1]
[1]	Includes the impact of WES’s (as defined in Note 1) equity offerings as described in Note 4. The $10.7 million decrease to partners’ capital, together with net income (loss) attributable to Western Gas Equity Partners, LP, totaled $71.1 million for the three months ended March 31, 2016.

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016		Mar. 31, 2015
Cash flows from operating activities
Net income (loss)		$ 117,759		$ (154,095)	[1]
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization		65,095		68,975	[1]
Impairments		6,518		272,624	[1]
Non-cash equity-based compensation expense		1,291		1,097	[1]
Deferred income taxes		1,852		5,809	[1]
Accretion and amortization of long-term obligations, net		5,496		2,112	[1]
Equity income, net	[2],[3],[4]	(16,814)		(18,220)	[1]
Distributions from equity investment earnings	[3]	19,855		18,706	[1]
Gain (loss) on divestiture and other, net		632		6	[1]
Changes in assets and liabilities:
(Increase) decrease in accounts receivable, net		12,513		(14,759)	[1]
Increase (decrease) in accounts and imbalance payables and accrued liabilities, net		18,446		12,897	[1]
Change in other items, net		3,240		(900)	[1]
Net cash provided by operating activities		235,883		194,252	[1]
Cash flows from investing activities
Capital expenditures		(136,987)		(211,567)	[1]
Investments in equity affiliates		474		(4,878)	[1]
Distributions from equity investments in excess of cumulative earnings	[3]	4,784	[5]	2,964	[1]
Net cash used in investing activities		(842,818)		(214,224)	[1]
Cash flows from financing activities
Borrowings, net of debt issuance costs		356,162		140,000	[1]
Repayments of debt		0		(31,150)	[1]
Increase (decrease) in outstanding checks		(994)		(2,198)	[1]
Distributions to WGP unitholders	[6]	(88,389)		(68,409)	[1]
Net contributions from (distributions to) Anadarko		(27,632)		1,293	[1]
Above-market component of swap extensions with Anadarko	[6]	6,813		0	[1]
Net cash provided by (used in) financing activities		618,697		12,582	[1]
Net increase (decrease) in cash and cash equivalents		11,762		(7,390)	[1]
Cash and cash equivalents at beginning of period		99,694	[7]	67,213	[1]
Cash and cash equivalents at end of period		111,456		59,823	[1]
Supplemental disclosures
Net distributions to (contributions from) Anadarko of other assets		714		205	[1]
Interest paid, net of capitalized interest		18,223		17,596	[1]
Taxes paid (reimbursements received)		67		(138)	[1]
Delaware Basin JV Gathering LLC [Member]
Supplemental disclosures
Acquisition of DBJV from Anadarko		0		174,276	[1]
Western Gas Partners, LP [Member]
Cash flows from financing activities
Proceeds from the issuance of common units, net of offering expenses		0		31,075	[1]
Distributions to noncontrolling interest owners of WES		(63,425)		(54,879)	[1]
Western Gas Partners, LP [Member] | Series A Preferred Units [Member]
Cash flows from financing activities
Proceeds from the issuance of WES Series A Preferred units, net of offering expenses		440,000		0	[1]
Affiliates [Member]
Cash flows from investing activities
Contributions in aid of construction costs from affiliates		2,369		0	[1]
Acquisitions from affiliates		(713,596)		(765)	[1]
Affiliates [Member] | Western Gas Partners, LP [Member]
Cash flows from financing activities
Distributions to WGP unitholders	[8]	(606)		(530)
Third Parties [Member]
Cash flows from investing activities
Proceeds from the sale of assets to third parties		138		22	[1]
Chipeta Processing Limited Liability Company [Member]
Cash flows from financing activities
Distributions to Chipeta noncontrolling interest owner		$ (3,838)		$ (3,150)	[1]
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.
[2]	Income earned from equity investments is classified as affiliate. See Note 1.
[3]	Income earned on, distributions from and contributions to equity investments are classified as affiliate. See Note 1.
[4]	Represents amounts earned or incurred on and subsequent to the date of acquisition of WES assets, as well as amounts earned or incurred by Anadarko on a historical basis related to WES assets prior to the acquisition of such assets by WES, recognized under gathering, treating or processing agreements, and purchase and sale agreements.
[5]	Distributions in excess of cumulative earnings, classified as investing cash flows in the consolidated statements of cash flows, is calculated on an individual investment basis.
[6]	See Note 5.
[7]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.
[8]	Represents distributions paid to other subsidiaries of Anadarko under WES’s partnership agreement (see Note 3 and Note 4).

Description of Business and Bas

Description of Business and Basis of Presentation	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Description of Business and Basis of Presentation	1. DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION General. Western Gas Equity Partners, LP is a Delaware master limited partnership formed in September 2012 to own three types of partnership interests in Western Gas Partners, LP. Western Gas Equity Partners, LP was formed by converting WGR Holdings, LLC into a limited partnership and changing its name. Western Gas Partners, LP (together with its subsidiaries, “WES”) is a Delaware master limited partnership formed by Anadarko Petroleum Corporation in 2007 to acquire, own, develop and operate midstream energy assets. For purposes of these consolidated financial statements, “WGP” refers to Western Gas Equity Partners, LP in its individual capacity or to Western Gas Equity Partners, LP and its subsidiaries, including Western Gas Holdings, LLC and WES, as the context requires. “WES GP” refers to Western Gas Holdings, LLC, individually as the general partner of WES, and excludes WES. WGP’s general partner, Western Gas Equity Holdings, LLC (“WGP GP”), is a wholly owned subsidiary of Anadarko Petroleum Corporation. WES GP owns all of the general partner interest in WES, which constitutes substantially all of its business, which primarily is to manage the affairs and operations of WES. Refer to Note 4 for a discussion of WGP’s holdings of WES equity. “Anadarko” refers to Anadarko Petroleum Corporation and its subsidiaries, excluding WGP and WGP GP, and “affiliates” refers to subsidiaries of Anadarko, excluding WGP, 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. WES 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 March 31, 2016 , WES’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 8 — 3 Natural gas processing plants/trains 18 5 — 2 NGL pipelines 2 — — 3 Natural gas pipelines 4 — — — 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. WES is constructing additional processing plants at the DBM complex, with operations expected to commence during the second quarter (Train IV) and second half (Train V) of 2016. WES has also made progress payments toward the construction of another cryogenic unit at the DBM complex (Train VI), with an expected in-service date of mid-2017. 1. DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (CONTINUED) Basis of presentation. The following table outlines WES’s ownership interests and the accounting method of consolidation used in WES’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 50 % Springfield 50.1 % Full consolidation Chipeta (3) 75 % (1) Investments in non-controlled entities over which WES exercises significant influence are accounted for under the equity method. “Equity investment throughput” refers to WES’s share of average throughput for these investments. (2) WGP proportionately consolidates WES’s 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 interests in the consolidated financial statements, in addition to the noncontrolling interests noted below. 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 WGP and entities in which it holds a controlling financial interest, including WES and WES GP. All significant intercompany transactions have been eliminated. The consolidated financial results of WES are included in WGP’s consolidated financial statements due to WGP’s 100% ownership interest in WES GP and WES GP’s control of WES. Throughout these notes to consolidated financial statements, and to the extent material, any differences between the consolidated financial results of WGP and WES are discussed separately. WGP has no independent operations or material assets other than its partnership interests in WES. WGP’s consolidated financial statements differ from those of WES primarily as a result of (i) the presentation of noncontrolling interest ownership (attributable to the limited partner interests in WES held by the public, other subsidiaries of Anadarko and private investors, see Note 4 ), (ii) the elimination of WES GP’s investment in WES with WES GP’s underlying capital account, (iii) the general and administrative expenses incurred by WGP, which are separate from, and in addition to, those incurred by WES, (iv) the inclusion of the impact of WGP equity balances and WGP distributions, and (v) WGP’s senior secured revolving credit facility (“WGP RCF”). See Note 9 . 1. DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (CONTINUED) Variable interest entity. At December 31, 2015, WGP’s ownership interest in WES consisted of a 34.6% limited partner interest, the entire 1.8% general partner interest, and all of the WES incentive distribution rights (“IDRs”). At December 31, 2015, other subsidiaries of Anadarko owned an 8.5% limited partner interest, with the remaining 55.1% limited partner interest owned by the public. Based on recently adopted guidance noted below in Recently issued accounting standards , WES is a variable interest entity (“VIE”) because the partners in WES with equity at risk lack the power, through voting or similar rights, to direct the activities that most significantly impact WES’s economic performance. A reporting entity that concludes it has a variable interest in a VIE must evaluate whether it has a controlling financial interest in the VIE, such that it is the VIE’s primary beneficiary and should consolidate. According to the aforementioned recently adopted guidance, WGP is the primary beneficiary of WES and therefore should consolidate because (i) WGP has the power to direct the activities of WES that most significantly affect its economic performance and (ii) WGP has the right to receive benefits or the obligation to absorb losses that could be potentially significant to WES. As noted above, WGP has no independent operations or material assets other than its partnership interests in WES. The assets of WES cannot be used by WGP for general partnership purposes. WES’s long-term debt is recourse to WES GP (wholly owned by WGP). In turn, WES GP is indemnified by wholly owned subsidiaries of Anadarko for any claims made against WES GP under the indentures governing WES’s outstanding notes or borrowings under WES’s senior unsecured revolving credit facility (“WES RCF”). WES’s sources of liquidity include cash and cash equivalents, cash flows generated from operations, interest income on its $260.0 million note receivable from Anadarko, available borrowing capacity under its revolving credit facility, and issuances of additional equity or debt securities. As further discussed in Note 2 , WGP purchased WES common units in connection with WES’s financing of an acquisition from Anadarko in March 2016. 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 WGP’s 2015 Form 10-K, as filed with the SEC on February 25, 2016. Management believes that the disclosures made are adequate to make the information not misleading. Noncontrolling interests. WGP’s noncontrolling interests in the consolidated financial statements consist of the following for all periods presented: (i) the 25% interest in Chipeta held by a third-party member, (ii) the publicly held limited partner interests in WES, (iii) the 2,011,380 WES common units issued by WES to other subsidiaries of Anadarko as part of the consideration paid for the acquisitions of the Non-Operated Marcellus Interest, the TEFR Interests and Springfield (see Note 2 ), (iv) the WES Class C units issued by WES to a subsidiary of Anadarko as part of the funding for the acquisition of DBM and (v) the WES Series A Preferred units issued to private investors as part of the funding of the Springfield acquisition. See Note 2 , Note 3 and Note 4 . When WES issues equity, the carrying amount of the noncontrolling interest reported by WGP is adjusted to reflect the noncontrolling ownership interest in WES. The resulting impact of such noncontrolling interest adjustment on WGP’s interest in WES is reflected as an adjustment to WGP’s partners’ capital. 1. DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (CONTINUED) Presentation of WES assets. The term “WES assets” refers to the assets indirectly owned and interests accounted for under the equity method (see Note 7 ) by WGP through its partnership interests in WES as of March 31, 2016 . Because WGP owns the entire interest in and controls WES GP, and WGP GP is owned and controlled by Anadarko, each of WES’s acquisitions of WES assets from Anadarko has been considered a transfer of net assets between entities under common control. As such, WES assets acquired from Anadarko were initially recorded at Anadarko’s historic carrying value, which did not correlate to the total acquisition price paid by WES. Further, after an acquisition of WES assets from Anadarko, WES and WGP (by virtue of its consolidation of WES) may be required to recast their financial statements to include the activities of such WES assets from the date of common control. See Note 2 . For those periods requiring recast, the consolidated financial statements for periods prior to the acquisition of WES 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 WES had owned the WES assets during the periods reported. Net income (loss) attributable to the WES assets acquired from Anadarko for periods prior to WES’s acquisition of the WES 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 that are received from insurance carriers are net of any deductibles related to the covered event. A receivable is recorded from insurance to the extent a loss is recognized from an involuntary conversion event and the likelihood of recovering such loss is deemed probable. To the extent that any insurance claim receivables are later judged not probable of recovery (e.g., due to new information), such amounts are expensed. A gain on involuntary conversion is recognized when the amount received from insurance exceeds the net book value of the retired asset(s). In addition, gains related to insurance recoveries are not recognized until all contingencies related to such proceeds have been resolved, that is, a non-refundable cash payment is received from the insurance carrier or there is 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 consolidated statements of cash flows. With respect to business interruption insurance claims, income is recognized only when non-refundable cash proceeds are received from insurers, which are presented in the consolidated statements of income 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 began accepting limited deliveries of gas in April 2016. Management expects Train III to return to full service by the end of the second quarter of 2016, along with new liquid handling and amine treating facilities. As of March 31, 2016 , and December 31, 2015, the consolidated balance sheets include a $49.0 million receivable for a property insurance claim related to the incident at the DBM complex. 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. WGP 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 2016-01, Financial Instruments—Overall: Recognition and Measurement of Financial Assets and Financial Liabilities (Subtopic 825-10). This ASU amends existing requirements on the classification and measurement of financial instruments. Changes to the current requirements primarily affect the accounting for equity investments, financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. This ASU is effective for annual periods beginning in 2018 with early adoption of certain provisions permitted. WGP is evaluating the impact of the adoption of this ASU on its consolidated financial statements. 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 master limited partnerships that apply the two-class method of calculating earnings per unit. When a general partner transfers or “drops down” net assets to a master limited partnership, 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. There was no impact to WGP’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. WGP 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 WGP’s consolidated balance sheet at December 31, 2015. See Note 9 . ASU 2015-02, Consolidation—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 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. WGP has evaluated the impact of the adoption of this ASU on its consolidated financial statements and determined that WES meets the criteria for a variable interest entity for which WGP is the primary beneficiary for accounting and disclosure purposes. Prior to the adoption of this ASU, WES was consolidated by WGP under the voting interest model. WGP will continue to consolidate WES under the variable interest model, thus the adoption of ASU 2015-02 on January 1, 2016, had no impact on WGP’s consolidated financial statements. See Basis of Presentation—Variable interest entity above. ASU 2014-09, Revenue from Contracts with Customers (Topic 606), ASU 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net) , and ASU 2016-10, Revenues from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing , which supersede the revenue recognition requirements in Topic 605, Revenue Recognition , require 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. WGP is required to adopt the new standards in the first quarter of 2018 using one of two retrospective application methods. WGP is continuing to evaluate the provisions of these ASUs, and has not determined the impact these standards may have on its consolidated financial statements and related disclosures or decided upon the method of adoption.

Acquisitions and Divestitures

Acquisitions and Divestitures	3 Months Ended
	Mar. 31, 2016
Property, Plant and Equipment [Abstract]
Acquisitions and Divestitures	2. ACQUISITIONS AND DIVESTITURES The following table presents the acquisitions completed by WES during 2016 and 2015 , and identifies the funding sources for such acquisitions: thousands except unit and percent amounts Acquisition Date Percentage Deferred Purchase Price Borrowings WES Common Units Issued WES’s 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) WES acquired Delaware Basin JV Gathering LLC (“DBJV”) from Anadarko. DBJV owns a 50% interest in a gathering system and related facilities, such interest being referred to in this report as the “DBJV system”. The DBJV gathering system and related facilities are located in the Delaware Basin in Loving, Ward, Winkler and Reeves Counties, Texas. WES will make a cash payment on March 31, 2020, to Anadarko as consideration for the acquisition of DBJV. WES currently estimates the future payment will be $282.8 million , the net present value of which was $174.3 million as of the acquisition date. See DBJV acquisition—deferred purchase price obligation - Anadarko below. (2) WES 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 WES 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 system.” The Springfield oil and gas gathering systems are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. WES financed the cash portion of the acquisition through: (i) borrowings of $247.5 million on the WES RCF, (ii) the issuance of 835,841 of WES common units to WGP and (iii) the issuance of WES Series A Preferred units noted above to private investors (the “initial issuance”). See Note 4 for further information regarding the WES Series A Preferred units, including the full exercise of an option granted in connection with the initial issuance. WGP financed the purchase of the WES common units by borrowing $25.0 million on the WGP RCF. See Note 9 . Springfield acquisition . Because the acquisition of Springfield was a transfer of net assets between entities under common control, WGP’s historical financial statements previously filed with the SEC have been recast in this Form 10-Q to include the results attributable to the Springfield system as if WES owned Springfield for all periods presented. The consolidated financial statements for periods prior to WES’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 WES had owned Springfield during the periods reported. The following table presents the impact of the Springfield system on Revenues and other, Equity income, net and Net income (loss) as presented in WGP’s historical consolidated statements of income: Three Months Ended March 31, 2015 thousands WGP Historical Springfield System Eliminations Combined Revenues and other $ 388,409 $ 48,614 $ (17 ) $ 437,006 Equity income, net 18,220 — — 18,220 Net income (loss) (177,392 ) 23,297 — (154,095 ) 2. ACQUISITIONS AND DIVESTITURES (CONTINUED) DBJV acquisition - deferred purchase price obligation - Anadarko. The consideration to be paid by WES 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 WES’s share in the Net Earnings (see definition below) of DBJV for the calendar years 2018 and 2019, less (b) WES’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 WES’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 March 31, 2016 and December 31, 2015, the net present value of this obligation was $193.2 million and $188.7 million , respectively, which was recorded on the consolidated balance sheet under Deferred purchase price obligation - Anadarko. Accretion expense for the three months ended March 31, 2016 and 2015, was $4.5 million and $1.4 million , respectively, which was recorded as a charge to Interest expense. Any subsequent changes to the estimated future payment obligation, if applicable, will be calculated using a discounted cash flow model with a 10% discount rate. Such changes will be recorded as adjustments within Common units on the consolidated balance sheets and consolidated statements of equity and partners’ capital, with accretion adjustments (financing-related) as a result of these changes recorded within Interest expense on the consolidated statements of income in the period of the change.

Partnership Distributions

Partnership Distributions	3 Months Ended
	Mar. 31, 2016
Distributions Made to Members or Limited Partners [Abstract]
Partnership Distributions	3. PARTNERSHIP DISTRIBUTIONS WGP partnership distributions. WGP’s partnership agreement requires WGP to distribute all of its available cash (as defined in its partnership agreement) to WGP unitholders of record on the applicable record date within 55 days of the end of each quarter. The Board of Directors of WGP GP declared the following cash distributions to WGP 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 $ 0.34250 $ 74,977 May 2015 June 30 0.36375 79,630 August 2015 September 30 0.38125 83,461 November 2015 December 31 0.40375 88,389 February 2016 2016 March 31 (1) $ 0.42375 $ 92,767 May 2016 (1) On April 22, 2016 , the Board of Directors of WGP GP declared a cash distribution to WGP unitholders of $0.42375 per unit, or $92.8 million in aggregate. The cash distribution is payable on May 22, 2016 , to WGP unitholders of record at the close of business on May 2, 2016 . 3. PARTNERSHIP DISTRIBUTIONS (CONTINUED) WES partnership distributions. WES’s partnership agreement requires WES to distribute all of its available cash (as defined in WES’s partnership agreement) to WES unitholders of record on the applicable record date within 45 days of the end of each quarter. The Board of Directors of WES GP declared the following cash distributions to WES’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 (1) $ 0.815 $ 158,905 May 2016 (1) On April 22, 2016 , the Board of Directors of WES GP declared a cash distribution to WES unitholders of $0.815 per unit, or $158.9 million in aggregate, including incentive distributions, but excluding distributions on WES Class C units (see WES Class C unit distributions below) and WES Series A Preferred units (see WES Series A Preferred unit distributions below). The cash distribution is payable on May 13, 2016 , to WES unitholders of record at the close of business on May 2, 2016 . WES Class C unit distributions. WES’s Class C units receive quarterly distributions at a rate equivalent to WES’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 WES’s distributions of WES’s available cash until they are converted to WES 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 WES’s common units for the ten days immediately preceding the payment date for the WES common unit distribution, less a 6% discount. WES records the PIK Class C unit distributions at fair value at the time of issuance. This Level 2 fair value measurement uses WES’s unit price as a significant input in the determination of the fair value. On February 11, 2016, WES distributed 323,584 PIK Class C units to APC Midstream Holdings, LLC (“AMH”), the holder of the Class C units, for the quarterly distribution period ended December 31, 2015. WES Series A Preferred unit distributions. As further described in Note 4 , WES issued Series A Preferred units representing limited partner interests in WES to private investors in March 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 WES Series A Preferred units are entitled to certain rights that are senior to the rights of holders of WES common and Class C units, such as rights to distributions and rights upon liquidation of WES. No payment or distribution on any junior equity security of WES, including WES common and Class C units, for any quarter is permitted prior to the payment in full of the WES Series A Preferred unit distribution (including any outstanding arrearages). For the quarter ended March 31, 2016 , the WES Series A Preferred unitholders will receive an aggregate cash distribution of $1.9 million , based on the quarterly per unit distribution prorated for the 18 -day period the 14,030,611 WES Series A Preferred units were outstanding during the first quarter of 2016. See Note 4 for further discussion of the WES Series A Preferred units.

Equity and Partners' Capital

Equity and Partners' Capital	3 Months Ended
	Mar. 31, 2016
Partners' Capital Notes [Abstract]
Equity and Partners' Capital	4. EQUITY AND PARTNERS’ CAPITAL Holdings of WGP equity. WGP’s common units are listed on the New York Stock Exchange under the symbol “WGP.” As of March 31, 2016 , Anadarko held 191,087,365 of WGP’s common units, representing an 87.3% limited partner interest in WGP, and, through its ownership of WGP GP, Anadarko indirectly held the entire non-economic general partner interest in WGP. The public held 27,832,015 WGP common units, representing a 12.7% limited partner interest in WGP. In June 2015, Anadarko sold 2,300,000 of its WGP common units to the public through an underwritten offering, including 300,000 common units pursuant to the full exercise of the underwriters’ over-allotment option. WGP did not receive any proceeds from, or incur any expense in, the public offering. Tangible equity units. In June 2015, Anadarko completed the public issuance of 9,200,000 , 7.50% tangible equity units (“TEUs”), including 1,200,000 TEUs pursuant to the full exercise of the underwriters’ over-allotment option, at a price to the public of $50.00 per TEU. Each TEU that Anadarko issued consists of (1) a prepaid equity purchase contract for WGP common units owned by Anadarko (subject to Anadarko’s right to elect to deliver shares of its common stock in lieu of such WGP common units) and (2) a senior amortizing note due June 7, 2018 . WGP did not receive any proceeds from, or incur any expense in, the public offering. See Note 7—Tangible Equity Units in the Notes to Consolidated Financial Statements under Part I , Item 1 of Anadarko’s Form 10-Q for the three months ended March 31, 2016 (which is not, and shall not be deemed to be, incorporated by reference herein), for a full discussion of the TEUs. Net income (loss) per common unit. For WGP, basic net income (loss) per common unit is calculated by dividing the limited partners’ interest in net income (loss) by the weighted-average number of common units outstanding during the period. Dilutive net income (loss) per common unit is calculated by dividing the limited partners’ interest in net income (loss) adjusted for distributions on the WES Series A Preferred units and a reallocation of the limited partners’ interest in net income (loss) assuming conversion of the WES Series A Preferred units into WES common units by the weighted-average number of WGP common units outstanding during the period. For the three months ended March 31, 2016, the impact of Series A Preferred units assuming conversion to WES common units would be anti-dilutive. Net income (loss) per common unit is calculated assuming that cash distributions are equal to the net income attributable to WGP. Net income (loss) attributable to the WES assets (as defined in Note 1 ) acquired from Anadarko for periods prior to WES’s acquisition of the WES assets is not allocated to the limited partners when calculating net income (loss) per common unit. Net income equal to the amount of available cash (as defined by WGP’s partnership agreement) is allocated to WGP common unitholders consistent with actual cash distributions. Holdings of WES equity. As of March 31, 2016 , WGP held 50,132,046 WES common units, representing a 31.5% limited partner interest in WES, and, through its ownership of WES GP, WGP indirectly held 2,583,068 general partner units, representing a 1.6% general partner interest in WES, and 100% of WES’s IDRs. As of March 31, 2016 , (i) other subsidiaries of Anadarko held 2,011,380 WES common units and 11,735,446 Class C units, representing an aggregate 8.7% limited partner interest in WES, (ii) the public held 78,523,141 WES common units, representing a 49.4% limited partner interest in WES, and (iii) private investors held 14,030,611 WES Series A Preferred units, representing an 8.8% limited partner interest in WES, which are all reflected as noncontrolling interests within the consolidated financial statements of WGP (see Note 1 and Note 2 ). WES equity offerings. Pursuant to WES’s registration statement filed with the SEC in August 2014 authorizing the issuance of up to an aggregate of $500.0 million of WES common units (“$500.0 million COP”), during the year ended December 31, 2015, WES issued 873,525 common units, at an average price of $66.61 , generating proceeds to WES 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 . WES issued no common units under the $500.0 million COP during the three months ended March 31, 2016 . 4. EQUITY AND PARTNERS’ CAPITAL (CONTINUED) WES Class C units. In connection with the closing of the DBM acquisition in November 2014, WES 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 the Unit Purchase Agreement (“UPA”) with Anadarko and AMH. All outstanding Class C units will convert into WES common units on a one-for-one basis on December 31, 2017, unless WES elects to convert such units earlier or Anadarko extends the conversion date. The Class C units were issued to partially fund WES’s acquisition of DBM, and the UPA contains an optional redemption feature that provides WES 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 WES 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 WES that owns a majority of the outstanding equity interests in DBM. As of March 31, 2016 , no such proceeds had been received, and no WES Class C units had been redeemed. WES Series A Preferred units. In connection with the closing of the Springfield acquisition on March 14, 2016, WES completed the issuance and sale of 14,030,611 Series A Preferred 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, WES issued an additional 7,892,220 Series A Preferred units pursuant to the full exercise of an option granted in connection with the initial issuance. The Series A Preferred unitholders may convert the WES Series A Preferred units into WES 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, WES may convert the WES 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 WES’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 WES common units at the then applicable conversion rate, (ii) if WES is not the surviving entity (or if WES is the surviving entity, but its common units will cease to be listed), require WES 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 WES is unable to cause such substantially equivalent securities to be issued), (iii) if WES is the surviving entity, continue to hold their Series A Preferred units, or (iv) require WES 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 WES common units at the discretion of WES. The Series A Preferred unitholders will vote on an as-converted basis with WES’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. Also in connection with the issuance of the WES Series A Preferred units, WES entered into a Registration Rights Agreement (the “Registration Rights Agreement”) with the Series A Preferred unit purchasers relating to the registered resale of the WES common units representing limited partner interests in WES issuable upon conversion of the WES Series A Preferred units. Pursuant to the Registration Rights Agreement, WES is required to use its commercially reasonable efforts to file and maintain a registration statement for the resale of the converted WES Series A Preferred units, with such registration statement to become effective no later than March 2018. 4. EQUITY AND PARTNERS’ CAPITAL (CONTINUED) WES interests . The following table summarizes WES’s common, Class C, Series A Preferred and general partner units issued during the three months ended March 31, 2016 : WES Common Units WES Class C Units WES Series A Preferred Units WES 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 — 323,584 — — 323,584 Springfield acquisition 2,089,602 — 14,030,611 — 16,120,213 Balance at March 31, 2016 130,666,567 11,735,446 14,030,611 2,583,068 159,015,692

Transactions with Affiliates

Transactions with Affiliates	3 Months Ended
	Mar. 31, 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 WES from services provided to Anadarko as well as from the sale of residue and NGLs to Anadarko. In addition, WES 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 WES assets, whether in providing services to affiliates or to third parties, including field labor, measurement and analysis, and other disbursements. A portion of general and administrative expenses is paid by Anadarko, which results in affiliate transactions pursuant to the reimbursement provisions of the omnibus agreements of WES and WGP. 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 WES 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 acquisition of WES 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 WES assets. Subsequent to the acquisition of WES 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 WES. Note receivable - Anadarko and Deferred purchase price obligation - Anadarko. Concurrently with the closing of WES’s May 2008 initial public offering, WES 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 $260.4 million and $252.3 million at March 31, 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 WES 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 . 5. TRANSACTIONS WITH AFFILIATES (CONTINUED) WGP working capital facility. On November 1, 2012, WGP entered into a $30.0 million working capital facility (the “WGP WCF”) with Anadarko as the lender. The WGP WCF is available exclusively to fund WGP’s working capital borrowings. Borrowings under the WGP WCF will mature on November 1, 2017 , and bear interest at London Interbank Offered Rate (“LIBOR”) plus 1.50% . See Note 9 . Commodity price swap agreements. WES 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 WES’s outstanding commodity price swap agreements as of March 31, 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 The following table summarizes gains and losses upon settlement of commodity price swap agreements recognized in the consolidated statements of income: Three Months Ended thousands 2016 2015 Gains (losses) on commodity price swap agreements related to sales: (1) Natural gas sales $ 7,041 $ 10,982 Natural gas liquids sales 20,070 44,432 Total 27,111 55,414 Losses on commodity price swap agreements related to purchases (2) (18,871 ) (34,179 ) Net gains (losses) on commodity price swap agreements $ 8,240 $ 21,235 (1) Reported in affiliate Natural gas and natural gas liquids sales in the consolidated statements of income in the period in which the related sale is recorded. (2) Reported in Cost of product in the consolidated statements of income in the period in which the related purchase is recorded. 5. TRANSACTIONS WITH AFFILIATES (CONTINUED) DJ Basin complex and Hugoton system swap extensions. On June 25, 2015, WES 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. 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 income. WES will also record a capital contribution from Anadarko in its 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 three months ended March 31, 2016 , the capital contribution from Anadarko was $6.8 million . 5. TRANSACTIONS WITH AFFILIATES (CONTINUED) Gathering and processing agreements. WES has significant gathering and processing arrangements with affiliates of Anadarko on a majority of its systems. WES’s gathering, treating and transportation throughput (excluding equity investment throughput) attributable to natural gas production owned or controlled by Anadarko was 37% and 56% for the three months ended March 31, 2016 and 2015 , respectively. WES’s processing throughput (excluding equity investment throughput) attributable to natural gas production owned or controlled by Anadarko was 61% and 52% for the three months ended March 31, 2016 and 2015 , respectively. WES’s gathering, treating and transportation throughput (excluding equity investment throughput) attributable to crude/NGL production owned or controlled by Anadarko was 64% and 100% for the three months ended March 31, 2016 and 2015 , respectively. 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. WES sells a significant amount of its natural gas, condensate and NGLs to Anadarko Energy Services Company (“AESC”), Anadarko’s marketing affiliate. In addition, WES purchases natural gas, condensate and NGLs from AESC pursuant to purchase agreements. WES’s purchase and sale agreements with AESC are generally one-year contracts, subject to annual renewal. Acquisitions from Anadarko. On March 14, 2016, WES acquired Springfield from Anadarko, and on March 2, 2015, WES acquired DBJV from Anadarko. See Note 2 for further information on these acquisitions. WGP LTIP. WGP GP awards phantom units under the Western Gas Equity Partners, LP 2012 Long-Term Incentive Plan (“WGP LTIP”) to its independent directors and executive officers. The phantom units awarded to the independent directors vest one year from the grant date, while awards granted to executive officers are subject to graded vesting over a three -year service period. Compensation expense under the WGP LTIP is recognized over the vesting period and was $56,000 and $55,000 for the three months ended March 31, 2016 and 2015 , respectively. WGP LTIP and Anadarko Incentive Plans. For the three months ended March 31, 2016 and 2015 , general and administrative expenses included $1.2 million and $1.0 million , respectively, of equity-based compensation expense, allocated to WES by Anadarko, for awards granted to the executive officers of WES GP and other employees under the 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, $1.1 million is reflected as a contribution to partners’ capital in the consolidated statement of equity and partners’ capital for the three months ended March 31, 2016 . WES LTIP. WES GP 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 WES. 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 March 31, 2016 and 2015 . Equipment purchases. The following table summarizes WES’s purchases from Anadarko of pipe and equipment: Three Months Ended March 31, 2016 2015 thousands Purchases Cash consideration $ 1,096 $ 765 Payable to affiliate 990 — Net carrying value 1,372 560 Partners’ capital adjustment $ 714 $ 205 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 thousands 2016 2015 Revenues and other (1) $ 272,584 $ 306,928 Equity income, net (1) 16,814 18,220 Cost of product (1) 24,580 43,895 Operation and maintenance (2) 17,975 16,817 General and administrative (3) 9,150 8,335 Operating expenses 51,705 69,047 Interest income (4) 4,225 4,225 Interest expense (5) 4,537 1,422 Distributions to WGP unitholders (6) 77,152 60,434 Distributions to WES unitholders (7) 606 530 Above-market component of swap extensions with Anadarko 6,813 — (1) Represents amounts earned or incurred on and subsequent to the date of acquisition of WES assets, as well as amounts earned or incurred by Anadarko on a historical basis related to WES assets prior to the acquisition of such assets by WES, recognized under gathering, treating or processing agreements, and purchase and sale agreements. (2) Represents expenses incurred on and subsequent to the date of the acquisition of WES assets, as well as expenses incurred by Anadarko on a historical basis related to WES assets prior to the acquisition of such assets by WES. (3) Represents general and administrative expense incurred on and subsequent to the date of WES’s acquisition of WES assets, as well as a management services fee for reimbursement of expenses incurred by Anadarko for periods prior to the acquisition of WES assets by WES. These amounts include equity-based compensation expense allocated to WES and WGP by Anadarko (see WES LTIP and WGP LTIP and Anadarko Incentive Plans within this Note 5 ) and amounts charged by Anadarko under the WGP omnibus agreement. (4) Represents interest income recognized on the note receivable from Anadarko. (5) For the three months ended March 31, 2016 and 2015 , includes WES’s accretion expense recognized on the Deferred purchase price obligation - Anadarko for the acquisition of DBJV (see Note 2 and Note 9 ) and for the three months ended March 31, 2015 , includes interest expense recognized on the WGP WCF (see Note 9 ). (6) Represents distributions paid under WGP’s partnership agreement (see Note 3 and Note 4 ). (7) Represents distributions paid to other subsidiaries of Anadarko under WES’s partnership agreement (see Note 3 and Note 4 ). Concentration of credit risk. Anadarko was the only customer from whom revenues exceeded 10% of consolidated revenues for all periods presented in the consolidated statements of income.

Property, Plant and Equipment

Property, Plant and Equipment	3 Months Ended
	Mar. 31, 2016
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	6. PROPERTY, PLANT AND EQUIPMENT A summary of the historical cost of property, plant and equipment is as follows: thousands Estimated Useful Life March 31, 2016 December 31, 2015 Land n/a $ 3,946 $ 3,744 Gathering systems 3 to 47 years 6,160,896 6,061,004 Pipelines and equipment 15 to 45 years 136,263 136,290 Assets under construction n/a 371,358 329,887 Other 3 to 40 years 28,346 25,853 Total property, plant and equipment 6,700,809 6,556,778 Accumulated depreciation 1,760,590 1,697,999 Net property, plant and equipment $ 4,940,219 $ 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 March 31, 2016 , net property, plant and equipment includes impairments of $6.5 million , primarily due to an impairment of $6.2 million at WES’s 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.

Equity Investments

Equity Investments	3 Months Ended
	Mar. 31, 2016
Equity Method Investments and Joint Ventures [Abstract]
Equity Investments	7. EQUITY INVESTMENTS The following table presents the activity of WES’s equity investments for the three months ended March 31, 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 (2,192 ) 3,993 550 5,419 257 4,097 4,690 16,814 Contributions — 106 — — — (580 ) — (474 ) Distributions — (3,848 ) (1,036 ) (5,428 ) (262 ) (4,160 ) (5,121 ) (19,855 ) Distributions in excess of cumulative earnings (1) (783 ) (877 ) (1,541 ) (172 ) (21 ) (1,390 ) — (4,784 ) Balance at March 31, 2016 $ 14,147 $ 49,813 $ 48,886 $ 116,908 $ 16,257 $ 192,770 $ 171,807 $ 610,588 (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 three months ended March 31, 2016 , an impairment loss was recognized by the managing partner of Fort Union. WES’s 14.81% share of the impairment loss was $3.0 million , which was recorded in Equity income, net in the consolidated statements of income.

Components of Working Capital

Components of Working Capital	3 Months Ended
	Mar. 31, 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 March 31, 2016 December 31, 2015 Trade receivables, net $ 130,559 $ 143,341 Other receivables, net 49,042 49,772 Total accounts receivable, net $ 179,601 $ 193,113 A summary of other current assets is as follows: thousands March 31, 2016 December 31, 2015 Natural gas liquids inventory $ 832 $ 2,403 Imbalance receivables 1,425 2,122 Prepaid insurance 1,807 2,998 Other — 1,034 Total other current assets $ 4,064 $ 8,557 A summary of accrued liabilities is as follows: thousands March 31, 2016 December 31, 2015 Accrued capital expenditures $ 68,152 $ 61,454 Accrued plant purchases 15,885 16,425 Accrued interest expense 34,578 26,194 Short-term asset retirement obligations 2,909 3,677 Short-term remediation and reclamation obligations 1,136 1,136 Income taxes payable 931 770 Other 4,789 9,440 Total accrued liabilities $ 128,380 $ 119,096

Debt and Interest Expense

Debt and Interest Expense	3 Months Ended
	Mar. 31, 2016
Debt Instruments [Abstract]
Debt and Interest Expense	9. DEBT AND INTEREST EXPENSE At March 31, 2016 , WGP’s debt consisted of borrowings on the WGP RCF, WES’s 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 WES RCF. The following table presents WES and WGP’s outstanding debt as of March 31, 2016 , and December 31, 2015 : March 31, 2016 December 31, 2015 thousands Principal Carrying Value Fair Value (1) Principal Carrying Value Fair Value (1) WGP RCF $ 28,000 $ 28,000 $ 28,000 $ — $ — $ — 2021 Notes 500,000 493,962 480,315 500,000 493,711 513,645 2022 Notes 670,000 668,482 597,975 670,000 668,432 595,744 2018 Notes 350,000 348,826 331,187 350,000 348,706 339,293 2044 Notes 400,000 389,744 313,752 400,000 389,707 321,499 2025 Notes 500,000 490,311 427,500 500,000 490,095 422,285 WES RCF 630,000 630,000 630,000 300,000 300,000 300,000 Total long-term debt $ 3,078,000 $ 3,049,325 $ 2,808,729 $ 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 WES and WGP’s debt activity for the three months ended March 31, 2016 : thousands Carrying Value Balance at December 31, 2015 $ 2,690,651 WES RCF borrowings 330,000 WGP RCF borrowings 28,000 Other 674 Balance at March 31, 2016 $ 3,049,325 WGP RCF. In March 2016, WGP entered into a $250.0 million WGP RCF which matures in March 2019. The WGP RCF may be used to buy WES common units and for general partnership purposes. The WGP RCF contains an accordion feature whereby WGP can increase the commitments under the WGP RCF up to an aggregate of $500.0 million , subject to receiving increased or new commitments from lenders and the satisfaction of certain other conditions precedent. The WGP RCF contains certain customary affirmative and negative covenants, including the maintenance of a consolidated leverage ratio of not more than 3.50 to 1.00 and limitations on the ability of WGP and WES GP to, among other things, (i) materially alter the character of their business on a consolidated basis from the midstream energy business, (ii) create, assume or suffer to exist liens on their assets, (iii) enter into transactions with affiliates, (iv) make distributions upon the occurrence of certain events of default, (v) create, incur or assume indebtedness, (vi) make dispositions of their assets, (vii) enter into sale and leasebacks and (vi) consolidate with or merge into any other entity or convey, transfer or lease their properties and assets substantially as an entirety to any person or entity. 9. DEBT AND INTEREST EXPENSE (CONTINUED) WGP borrowed $28.0 million under the WGP RCF to fund the purchase of 835,841 WES common units (see Note 2 ) and to pay fees and expenses associated with entering into the WGP RCF. Pursuant to a collateral agreement with the WGP RCF lenders, WGP’s obligations under the WGP RCF are secured by a first priority lien on all of WGP’s assets (not including the consolidated assets of WES), as well as all present and after acquired equity interests owned by WGP in WES GP and WES. Borrowings under the WGP RCF bear interest, at WGP’s option, at either (a) a base rate equal to the greatest of (i) the Prime Rate, (ii) the Federal Funds Effective Rate plus 0.50% and (iii) LIBOR plus 1.00% , in each case plus applicable margins ranging from 1.00% to 1.75% based upon WGP’s consolidated leverage ratio or (b) LIBOR (with a floor of 0% ), plus applicable margins ranging from 2.00% to 2.75% based upon WGP’s consolidated leverage ratio. The unused portion of the WGP RCF is subject to a quarterly commitment fee ranging from 0.30% to 0.50% per annum on the daily unused amount of the WGP RCF based upon WGP’s consolidated leverage ratio. At March 31, 2016 , the interest rate and commitment fee rate on the WGP RCF was 2.69% and 0.30% , respectively. As of March 31, 2016 , WGP had $28.0 million of outstanding borrowings ( $222.0 million available borrowing capacity) and was in compliance with all covenants under the WGP RCF. WGP working capital facility. On November 1, 2012, WGP entered into a $30.0 million working capital facility (the “WGP WCF”) with Anadarko as the lender. Borrowings under the facility will mature on November 1, 2017. The interest rate was 1.94% and 1.68% at March 31, 2016 and 2015 , respectively. As of March 31, 2016 , WGP had no outstanding borrowings and $30.0 million available for borrowing under the WGP WCF. At March 31, 2016 , WGP was in compliance with all covenants under the WGP WCF. WES Senior Notes. At March 31, 2016 , WES was in compliance with all covenants under the indentures governing its outstanding notes. WES RCF. The interest rate on the WES RCF, which matures in February 2019, was 1.74% and 1.48% at March 31, 2016 and 2015 , respectively. The facility fee rate was 0.20% at March 31, 2016 and 2015 . As of March 31, 2016 , WES had $630.0 million of outstanding borrowings, $4.9 million in outstanding letters of credit and $565.1 million available for borrowing under the WES RCF. At March 31, 2016 , WES was in compliance with all covenants under the WES RCF. In April 2016, WES repaid $250.0 million of outstanding borrowings under the WES RCF, $247.5 million of which was funded with the proceeds from the issuance of the additional WES Series A Preferred units (see Note 4 ). 9. DEBT AND INTEREST EXPENSE (CONTINUED) Interest expense. The following table summarizes the amounts included in interest expense: Three Months Ended thousands 2016 2015 Third parties Long-term debt $ 27,856 $ 23,342 Amortization of debt issuance costs and commitment fees 1,595 1,292 Capitalized interest (1,849 ) (3,094 ) Total interest expense – third parties 27,602 21,540 Affiliates WGP WCF — 2 Deferred purchase price obligation – Anadarko (1) 4,537 1,420 Total interest expense – affiliates 4,537 1,422 Interest expense $ 32,139 $ 22,962 (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	3 Months Ended
	Mar. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. COMMITMENTS AND CONTINGENCIES Litigation and legal proceedings. From time to time, WGP, through its partnership interests in WES, 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 financial condition, results of operations or cash flows of WGP. Other commitments. WES has short-term payment obligations, or commitments, related to its capital spending programs, as well as those of its unconsolidated affiliates. As of March 31, 2016 , WES had unconditional payment obligations for services to be rendered or products to be delivered in connection with its capital projects of $90.0 million , the majority of which is expected to be paid in the next twelve months. These commitments relate primarily to the construction of Trains IV, V and VI at the DBM complex and expansion projects at the DBJV system and the DJ Basin complex. Lease commitments. Anadarko, on WES’s behalf, has entered into lease agreements for corporate offices, shared field offices and a warehouse supporting WES’s operations, for which Anadarko charges WES 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 $8.9 million and $8.0 million for the three months ended March 31, 2016 and 2015 , respectively.

Description of Business and B19

Description of Business and Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Business combinations policy	Basis of presentation. The following table outlines WES’s ownership interests and the accounting method of consolidation used in WES’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 50 % Springfield 50.1 % Full consolidation Chipeta (3) 75 % (1) Investments in non-controlled entities over which WES exercises significant influence are accounted for under the equity method. “Equity investment throughput” refers to WES’s share of average throughput for these investments. (2) WGP proportionately consolidates WES’s 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 interests in the consolidated financial statements, in addition to the noncontrolling interests noted below. 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 WGP and entities in which it holds a controlling financial interest, including WES and WES GP. All significant intercompany transactions have been eliminated. The consolidated financial results of WES are included in WGP’s consolidated financial statements due to WGP’s 100% ownership interest in WES GP and WES GP’s control of WES. Throughout these notes to consolidated financial statements, and to the extent material, any differences between the consolidated financial results of WGP and WES are discussed separately. WGP has no independent operations or material assets other than its partnership interests in WES. WGP’s consolidated financial statements differ from those of WES primarily as a result of (i) the presentation of noncontrolling interest ownership (attributable to the limited partner interests in WES held by the public, other subsidiaries of Anadarko and private investors, see Note 4 ), (ii) the elimination of WES GP’s investment in WES with WES GP’s underlying capital account, (iii) the general and administrative expenses incurred by WGP, which are separate from, and in addition to, those incurred by WES, (iv) the inclusion of the impact of WGP equity balances and WGP distributions, and (v) WGP’s senior secured revolving credit facility (“WGP RCF”). See Note 9 . Noncontrolling interests. WGP’s noncontrolling interests in the consolidated financial statements consist of the following for all periods presented: (i) the 25% interest in Chipeta held by a third-party member, (ii) the publicly held limited partner interests in WES, (iii) the 2,011,380 WES common units issued by WES to other subsidiaries of Anadarko as part of the consideration paid for the acquisitions of the Non-Operated Marcellus Interest, the TEFR Interests and Springfield (see Note 2 ), (iv) the WES Class C units issued by WES to a subsidiary of Anadarko as part of the funding for the acquisition of DBM and (v) the WES Series A Preferred units issued to private investors as part of the funding of the Springfield acquisition. See Note 2 , Note 3 and Note 4 . When WES issues equity, the carrying amount of the noncontrolling interest reported by WGP is adjusted to reflect the noncontrolling ownership interest in WES. The resulting impact of such noncontrolling interest adjustment on WGP’s interest in WES is reflected as an adjustment to WGP’s partners’ capital. Presentation of WES assets. The term “WES assets” refers to the assets indirectly owned and interests accounted for under the equity method (see Note 7 ) by WGP through its partnership interests in WES as of March 31, 2016 . Because WGP owns the entire interest in and controls WES GP, and WGP GP is owned and controlled by Anadarko, each of WES’s acquisitions of WES assets from Anadarko has been considered a transfer of net assets between entities under common control. As such, WES assets acquired from Anadarko were initially recorded at Anadarko’s historic carrying value, which did not correlate to the total acquisition price paid by WES. Further, after an acquisition of WES assets from Anadarko, WES and WGP (by virtue of its consolidation of WES) may be required to recast their financial statements to include the activities of such WES assets from the date of common control. See Note 2 . For those periods requiring recast, the consolidated financial statements for periods prior to the acquisition of WES 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 WES had owned the WES assets during the periods reported. Net income (loss) attributable to the WES assets acquired from Anadarko for periods prior to WES’s acquisition of the WES assets is not allocated to the limited partners. Springfield acquisition . Because the acquisition of Springfield was a transfer of net assets between entities under common control, WGP’s historical financial statements previously filed with the SEC have been recast in this Form 10-Q to include the results attributable to the Springfield system as if WES owned Springfield for all periods presented. The consolidated financial statements for periods prior to WES’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 WES had owned Springfield during the periods reported.
Consolidation variable interest entity policy	Variable interest entity. At December 31, 2015, WGP’s ownership interest in WES consisted of a 34.6% limited partner interest, the entire 1.8% general partner interest, and all of the WES incentive distribution rights (“IDRs”). At December 31, 2015, other subsidiaries of Anadarko owned an 8.5% limited partner interest, with the remaining 55.1% limited partner interest owned by the public. Based on recently adopted guidance noted below in Recently issued accounting standards , WES is a variable interest entity (“VIE”) because the partners in WES with equity at risk lack the power, through voting or similar rights, to direct the activities that most significantly impact WES’s economic performance. A reporting entity that concludes it has a variable interest in a VIE must evaluate whether it has a controlling financial interest in the VIE, such that it is the VIE’s primary beneficiary and should consolidate. According to the aforementioned recently adopted guidance, WGP is the primary beneficiary of WES and therefore should consolidate because (i) WGP has the power to direct the activities of WES that most significantly affect its economic performance and (ii) WGP has the right to receive benefits or the obligation to absorb losses that could be potentially significant to WES. As noted above, WGP has no independent operations or material assets other than its partnership interests in WES. The assets of WES cannot be used by WGP for general partnership purposes. WES’s long-term debt is recourse to WES GP (wholly owned by WGP). In turn, WES GP is indemnified by wholly owned subsidiaries of Anadarko for any claims made against WES GP under the indentures governing WES’s outstanding notes or borrowings under WES’s senior unsecured revolving credit facility (“WES RCF”). WES’s sources of liquidity include cash and cash equivalents, cash flows generated from operations, interest income on its $260.0 million note receivable from Anadarko, available borrowing capacity under its revolving credit facility, and issuances of additional equity or debt securities. As further discussed in Note 2 , WGP purchased WES common units in connection with WES’s financing of an acquisition from Anadarko in March 2016.
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.
Fair value policy	DBJV acquisition - deferred purchase price obligation - Anadarko. The consideration to be paid by WES 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 WES’s share in the Net Earnings (see definition below) of DBJV for the calendar years 2018 and 2019, less (b) WES’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 WES’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 March 31, 2016 and December 31, 2015, the net present value of this obligation was $193.2 million and $188.7 million , respectively, which was recorded on the consolidated balance sheet under Deferred purchase price obligation - Anadarko. Accretion expense for the three months ended March 31, 2016 and 2015, was $4.5 million and $1.4 million , respectively, which was recorded as a charge to Interest expense. Any subsequent changes to the estimated future payment obligation, if applicable, will be calculated using a discounted cash flow model with a 10% discount rate. Such changes will be recorded as adjustments within Common units on the consolidated balance sheets and consolidated statements of equity and partners’ capital, with accretion adjustments (financing-related) as a result of these changes recorded within Interest expense on the consolidated statements of income in the period of the change. WES Class C unit distributions. WES’s Class C units receive quarterly distributions at a rate equivalent to WES’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 WES’s distributions of WES’s available cash until they are converted to WES 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 WES’s common units for the ten days immediately preceding the payment date for the WES common unit distribution, less a 6% discount. WES records the PIK Class C unit distributions at fair value at the time of issuance. This Level 2 fair value measurement uses WES’s unit price as a significant input in the determination of the fair value. On February 11, 2016, WES distributed 323,584 PIK Class C units to APC Midstream Holdings, LLC (“AMH”), the holder of the Class C units, for the quarterly distribution period ended December 31, 2015. Note receivable - Anadarko and Deferred purchase price obligation - Anadarko. Concurrently with the closing of WES’s May 2008 initial public offering, WES 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 $260.4 million and $252.3 million at March 31, 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.
Net income (loss) per common unit policy	Net income (loss) per common unit. For WGP, basic net income (loss) per common unit is calculated by dividing the limited partners’ interest in net income (loss) by the weighted-average number of common units outstanding during the period. Dilutive net income (loss) per common unit is calculated by dividing the limited partners’ interest in net income (loss) adjusted for distributions on the WES Series A Preferred units and a reallocation of the limited partners’ interest in net income (loss) assuming conversion of the WES Series A Preferred units into WES common units by the weighted-average number of WGP common units outstanding during the period. For the three months ended March 31, 2016, the impact of Series A Preferred units assuming conversion to WES common units would be anti-dilutive. Net income (loss) per common unit is calculated assuming that cash distributions are equal to the net income attributable to WGP. Net income (loss) attributable to the WES assets (as defined in Note 1 ) acquired from Anadarko for periods prior to WES’s acquisition of the WES assets is not allocated to the limited partners when calculating net income (loss) per common unit. Net income equal to the amount of available cash (as defined by WGP’s partnership agreement) is allocated to WGP common unitholders consistent with actual cash distributions.
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. WGP 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 2016-01, Financial Instruments—Overall: Recognition and Measurement of Financial Assets and Financial Liabilities (Subtopic 825-10). This ASU amends existing requirements on the classification and measurement of financial instruments. Changes to the current requirements primarily affect the accounting for equity investments, financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. This ASU is effective for annual periods beginning in 2018 with early adoption of certain provisions permitted. WGP is evaluating the impact of the adoption of this ASU on its consolidated financial statements. 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 master limited partnerships that apply the two-class method of calculating earnings per unit. When a general partner transfers or “drops down” net assets to a master limited partnership, 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. There was no impact to WGP’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. WGP 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 WGP’s consolidated balance sheet at December 31, 2015. See Note 9 . ASU 2015-02, Consolidation—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 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. WGP has evaluated the impact of the adoption of this ASU on its consolidated financial statements and determined that WES meets the criteria for a variable interest entity for which WGP is the primary beneficiary for accounting and disclosure purposes. Prior to the adoption of this ASU, WES was consolidated by WGP under the voting interest model. WGP will continue to consolidate WES under the variable interest model, thus the adoption of ASU 2015-02 on January 1, 2016, had no impact on WGP’s consolidated financial statements. See Basis of Presentation—Variable interest entity above. ASU 2014-09, Revenue from Contracts with Customers (Topic 606), ASU 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net) , and ASU 2016-10, Revenues from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing , which supersede the revenue recognition requirements in Topic 605, Revenue Recognition , require 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. WGP is required to adopt the new standards in the first quarter of 2018 using one of two retrospective application methods. WGP is continuing to evaluate the provisions of these ASUs, and has not determined the impact these standards may have on its consolidated financial statements and related disclosures or decided upon the method of adoption.

Description of Business and B20

Description of Business and Basis of Presentation (Tables)	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Assets and Investments Table	As of March 31, 2016 , WES’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 8 — 3 Natural gas processing plants/trains 18 5 — 2 NGL pipelines 2 — — 3 Natural gas pipelines 4 — — — Oil pipelines — 1 — 1
Ownership Interest and Method of Consolidation Table	The following table outlines WES’s ownership interests and the accounting method of consolidation used in WES’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 50 % Springfield 50.1 % Full consolidation Chipeta (3) 75 % (1) Investments in non-controlled entities over which WES exercises significant influence are accounted for under the equity method. “Equity investment throughput” refers to WES’s share of average throughput for these investments. (2) WGP proportionately consolidates WES’s 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 interests in the consolidated financial statements, in addition to the noncontrolling interests noted below.

Acquisitions and Divestitures (

Acquisitions and Divestitures (Tables)	3 Months Ended
	Mar. 31, 2016
Property, Plant and Equipment [Abstract]
Acquisitions Table	The following table presents the acquisitions completed by WES during 2016 and 2015 , and identifies the funding sources for such acquisitions: thousands except unit and percent amounts Acquisition Date Percentage Deferred Purchase Price Borrowings WES Common Units Issued WES’s 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) WES acquired Delaware Basin JV Gathering LLC (“DBJV”) from Anadarko. DBJV owns a 50% interest in a gathering system and related facilities, such interest being referred to in this report as the “DBJV system”. The DBJV gathering system and related facilities are located in the Delaware Basin in Loving, Ward, Winkler and Reeves Counties, Texas. WES will make a cash payment on March 31, 2020, to Anadarko as consideration for the acquisition of DBJV. WES currently estimates the future payment will be $282.8 million , the net present value of which was $174.3 million as of the acquisition date. See DBJV acquisition—deferred purchase price obligation - Anadarko below. (2) WES 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 WES 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 system.” The Springfield oil and gas gathering systems are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. WES financed the cash portion of the acquisition through: (i) borrowings of $247.5 million on the WES RCF, (ii) the issuance of 835,841 of WES common units to WGP and (iii) the issuance of WES Series A Preferred units noted above to private investors (the “initial issuance”). See Note 4 for further information regarding the WES Series A Preferred units, including the full exercise of an option granted in connection with the initial issuance. WGP financed the purchase of the WES common units by borrowing $25.0 million on the WGP RCF. See Note 9 .
Impact to Historical Consolidated Statements of Income Table	The following table presents the impact of the Springfield system on Revenues and other, Equity income, net and Net income (loss) as presented in WGP’s historical consolidated statements of income: Three Months Ended March 31, 2015 thousands WGP Historical Springfield System Eliminations Combined Revenues and other $ 388,409 $ 48,614 $ (17 ) $ 437,006 Equity income, net 18,220 — — 18,220 Net income (loss) (177,392 ) 23,297 — (154,095 )

Partnership Distributions (Tabl

Partnership Distributions (Tables)	3 Months Ended
	Mar. 31, 2016
Distribution Made to Limited Partner [Line Items]
Cash Distributions Tables	The Board of Directors of WGP GP declared the following cash distributions to WGP 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 $ 0.34250 $ 74,977 May 2015 June 30 0.36375 79,630 August 2015 September 30 0.38125 83,461 November 2015 December 31 0.40375 88,389 February 2016 2016 March 31 (1) $ 0.42375 $ 92,767 May 2016 (1) On April 22, 2016 , the Board of Directors of WGP GP declared a cash distribution to WGP unitholders of $0.42375 per unit, or $92.8 million in aggregate. The cash distribution is payable on May 22, 2016 , to WGP unitholders of record at the close of business on May 2, 2016 .
Western Gas Partners, LP [Member]
Distribution Made to Limited Partner [Line Items]
Cash Distributions Tables	The Board of Directors of WES GP declared the following cash distributions to WES’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 (1) $ 0.815 $ 158,905 May 2016 (1) On April 22, 2016 , the Board of Directors of WES GP declared a cash distribution to WES unitholders of $0.815 per unit, or $158.9 million in aggregate, including incentive distributions, but excluding distributions on WES Class C units (see WES Class C unit distributions below) and WES Series A Preferred units (see WES Series A Preferred unit distributions below). The cash distribution is payable on May 13, 2016 , to WES unitholders of record at the close of business on May 2, 2016 .

Equity and Partners' Capital (T

Equity and Partners' Capital (Tables)	3 Months Ended
	Mar. 31, 2016
Partners' Capital Notes [Abstract]
Partnership Interests Table	The following table summarizes WES’s common, Class C, Series A Preferred and general partner units issued during the three months ended March 31, 2016 : WES Common Units WES Class C Units WES Series A Preferred Units WES 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 — 323,584 — — 323,584 Springfield acquisition 2,089,602 — 14,030,611 — 16,120,213 Balance at March 31, 2016 130,666,567 11,735,446 14,030,611 2,583,068 159,015,692

Transactions with Affiliates (T

Transactions with Affiliates (Tables)	3 Months Ended
	Mar. 31, 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 WES’s outstanding commodity price swap agreements as of March 31, 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 income: Three Months Ended thousands 2016 2015 Gains (losses) on commodity price swap agreements related to sales: (1) Natural gas sales $ 7,041 $ 10,982 Natural gas liquids sales 20,070 44,432 Total 27,111 55,414 Losses on commodity price swap agreements related to purchases (2) (18,871 ) (34,179 ) Net gains (losses) on commodity price swap agreements $ 8,240 $ 21,235 (1) Reported in affiliate Natural gas and natural gas liquids sales in the consolidated statements of income in the period in which the related sale is recorded. (2) Reported in Cost of product in the consolidated statements of income 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. 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	The following table summarizes WES’s purchases from Anadarko of pipe and equipment: Three Months Ended March 31, 2016 2015 thousands Purchases Cash consideration $ 1,096 $ 765 Payable to affiliate 990 — Net carrying value 1,372 560 Partners’ capital adjustment $ 714 $ 205 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 thousands 2016 2015 Revenues and other (1) $ 272,584 $ 306,928 Equity income, net (1) 16,814 18,220 Cost of product (1) 24,580 43,895 Operation and maintenance (2) 17,975 16,817 General and administrative (3) 9,150 8,335 Operating expenses 51,705 69,047 Interest income (4) 4,225 4,225 Interest expense (5) 4,537 1,422 Distributions to WGP unitholders (6) 77,152 60,434 Distributions to WES unitholders (7) 606 530 Above-market component of swap extensions with Anadarko 6,813 — (1) Represents amounts earned or incurred on and subsequent to the date of acquisition of WES assets, as well as amounts earned or incurred by Anadarko on a historical basis related to WES assets prior to the acquisition of such assets by WES, recognized under gathering, treating or processing agreements, and purchase and sale agreements. (2) Represents expenses incurred on and subsequent to the date of the acquisition of WES assets, as well as expenses incurred by Anadarko on a historical basis related to WES assets prior to the acquisition of such assets by WES. (3) Represents general and administrative expense incurred on and subsequent to the date of WES’s acquisition of WES assets, as well as a management services fee for reimbursement of expenses incurred by Anadarko for periods prior to the acquisition of WES assets by WES. These amounts include equity-based compensation expense allocated to WES and WGP by Anadarko (see WES LTIP and WGP LTIP and Anadarko Incentive Plans within this Note 5 ) and amounts charged by Anadarko under the WGP omnibus agreement. (4) Represents interest income recognized on the note receivable from Anadarko. (5) For the three months ended March 31, 2016 and 2015 , includes WES’s accretion expense recognized on the Deferred purchase price obligation - Anadarko for the acquisition of DBJV (see Note 2 and Note 9 ) and for the three months ended March 31, 2015 , includes interest expense recognized on the WGP WCF (see Note 9 ). (6) Represents distributions paid under WGP’s partnership agreement (see Note 3 and Note 4 ). (7) Represents distributions paid to other subsidiaries of Anadarko under WES’s partnership agreement (see Note 3 and Note 4 ).

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	3 Months Ended
	Mar. 31, 2016
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment Table	A summary of the historical cost of property, plant and equipment is as follows: thousands Estimated Useful Life March 31, 2016 December 31, 2015 Land n/a $ 3,946 $ 3,744 Gathering systems 3 to 47 years 6,160,896 6,061,004 Pipelines and equipment 15 to 45 years 136,263 136,290 Assets under construction n/a 371,358 329,887 Other 3 to 40 years 28,346 25,853 Total property, plant and equipment 6,700,809 6,556,778 Accumulated depreciation 1,760,590 1,697,999 Net property, plant and equipment $ 4,940,219 $ 4,858,779

Equity Investments (Tables)

Equity Investments (Tables)	3 Months Ended
	Mar. 31, 2016
Equity Method Investments and Joint Ventures [Abstract]
Equity Investments Table	The following table presents the activity of WES’s equity investments for the three months ended March 31, 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 (2,192 ) 3,993 550 5,419 257 4,097 4,690 16,814 Contributions — 106 — — — (580 ) — (474 ) Distributions — (3,848 ) (1,036 ) (5,428 ) (262 ) (4,160 ) (5,121 ) (19,855 ) Distributions in excess of cumulative earnings (1) (783 ) (877 ) (1,541 ) (172 ) (21 ) (1,390 ) — (4,784 ) Balance at March 31, 2016 $ 14,147 $ 49,813 $ 48,886 $ 116,908 $ 16,257 $ 192,770 $ 171,807 $ 610,588 (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)	3 Months Ended
	Mar. 31, 2016
Components Of Working Capital [Abstract]
Accounts Receivable, Net Table	A summary of accounts receivable, net is as follows: thousands March 31, 2016 December 31, 2015 Trade receivables, net $ 130,559 $ 143,341 Other receivables, net 49,042 49,772 Total accounts receivable, net $ 179,601 $ 193,113
Other Current Assets Table	A summary of other current assets is as follows: thousands March 31, 2016 December 31, 2015 Natural gas liquids inventory $ 832 $ 2,403 Imbalance receivables 1,425 2,122 Prepaid insurance 1,807 2,998 Other — 1,034 Total other current assets $ 4,064 $ 8,557
Accrued Liabilities Table	A summary of accrued liabilities is as follows: thousands March 31, 2016 December 31, 2015 Accrued capital expenditures $ 68,152 $ 61,454 Accrued plant purchases 15,885 16,425 Accrued interest expense 34,578 26,194 Short-term asset retirement obligations 2,909 3,677 Short-term remediation and reclamation obligations 1,136 1,136 Income taxes payable 931 770 Other 4,789 9,440 Total accrued liabilities $ 128,380 $ 119,096

Debt and Interest Expense (Tabl

Debt and Interest Expense (Tables)	3 Months Ended
	Mar. 31, 2016
Debt Instruments [Abstract]
Debt Outstanding and Debt Activity Tables	The following table presents WES and WGP’s outstanding debt as of March 31, 2016 , and December 31, 2015 : March 31, 2016 December 31, 2015 thousands Principal Carrying Value Fair Value (1) Principal Carrying Value Fair Value (1) WGP RCF $ 28,000 $ 28,000 $ 28,000 $ — $ — $ — 2021 Notes 500,000 493,962 480,315 500,000 493,711 513,645 2022 Notes 670,000 668,482 597,975 670,000 668,432 595,744 2018 Notes 350,000 348,826 331,187 350,000 348,706 339,293 2044 Notes 400,000 389,744 313,752 400,000 389,707 321,499 2025 Notes 500,000 490,311 427,500 500,000 490,095 422,285 WES RCF 630,000 630,000 630,000 300,000 300,000 300,000 Total long-term debt $ 3,078,000 $ 3,049,325 $ 2,808,729 $ 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 WES and WGP’s debt activity for the three months ended March 31, 2016 : thousands Carrying Value Balance at December 31, 2015 $ 2,690,651 WES RCF borrowings 330,000 WGP RCF borrowings 28,000 Other 674 Balance at March 31, 2016 $ 3,049,325
Interest Expense Table	The following table summarizes the amounts included in interest expense: Three Months Ended thousands 2016 2015 Third parties Long-term debt $ 27,856 $ 23,342 Amortization of debt issuance costs and commitment fees 1,595 1,292 Capitalized interest (1,849 ) (3,094 ) Total interest expense – third parties 27,602 21,540 Affiliates WGP WCF — 2 Deferred purchase price obligation – Anadarko (1) 4,537 1,420 Total interest expense – affiliates 4,537 1,422 Interest expense $ 32,139 $ 22,962 (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 B29

Description of Business and Basis of Presentation - Asset Table (Details) - Western Gas Partners, LP [Member]	Mar. 31, 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	18
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	4
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	8
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 B30

Description of Business and Basis of Presentation - Ownership Interest and Method of Consolidation Table (Details)	3 Months Ended
	Mar. 31, 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%
Western Gas Partners, LP [Member] | Equity Investments [Member] | Fort Union [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	14.81%	[1]
Western Gas Partners, LP [Member] | Equity Investments [Member] | White Cliffs [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	10.00%	[1]
Western Gas Partners, LP [Member] | Equity Investments [Member] | Rendezvous [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	22.00%	[1]
Western Gas Partners, LP [Member] | Equity Investments [Member] | Mont Belvieu JV [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	25.00%	[1]
Western Gas Partners, LP [Member] | Equity Investments [Member] | Texas Express Pipeline LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	20.00%	[1]
Western Gas Partners, LP [Member] | Equity Investments [Member] | Texas Express Gathering LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	20.00%	[1]
Western Gas Partners, LP [Member] | Equity Investments [Member] | Front Range Pipeline LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	33.33%	[1]
Western Gas Partners, LP [Member] | Proportionate Consolidation [Member] | Non-Operated Marcellus Interest [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	33.75%	[2]
Western Gas Partners, LP [Member] | Proportionate Consolidation [Member] | Anadarko-Operated Marcellus Interest [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	33.75%	[2]
Western Gas Partners, LP [Member] | Proportionate Consolidation [Member] | Newcastle [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	50.00%	[2]
Western Gas Partners, LP [Member] | 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]
Western Gas Partners, LP [Member] | Proportionate Consolidation [Member] | Springfield Pipeline LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	50.10%	[2]
Western Gas Partners, LP [Member] | 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 WES exercises significant influence are accounted for under the equity method. “Equity investment throughput” refers to WES’s share of average throughput for these investments.
[2]	WGP proportionately consolidates WES’s 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 interests in the consolidated financial statements, in addition to the noncontrolling interests noted below.

Description of Business and B31

Description of Business and Basis of Presentation - Additional Information (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2016USD ($)Mcf / dshares	Dec. 31, 2015USD ($)		May. 31, 2008USD ($)
Note receivable - Anadarko	$ 260,000,000	$ 260,000,000	[1]
Other assets	15,549,000	13,001,000	[1]
Long-term debt	$ 3,049,325,000	2,690,651,000	[1]
Restatement Adjustment [Member] | Accounting Standards Update 2015-03 And 2015-15 [Member]
Other assets		16,700,000
Long-term debt		$ 16,700,000
Chipeta Processing Limited Liability Company [Member]
Ownership interest by noncontrolling interest owner	25.00%
Public [Member]
Ownership interest	12.70%
Western Gas Partners, LP [Member]
General partner's interest	1.60%	1.80%
Western Gas Partners, LP [Member] | Delaware Basin Midstream Complex [Member]
Insurance receivable	$ 49,000,000	$ 49,000,000
Western Gas Partners, LP [Member] | Delaware Basin Midstream Complex [Member] | Train II [Member]
Plant capacity | Mcf / d	100,000
Western Gas Partners, LP [Member] | Delaware Basin Midstream Complex [Member] | Train III [Member]
Plant capacity | Mcf / d	200,000
Western Gas Partners, LP [Member] | Other Subsidiaries Of Anadarko [Member]
Ownership interest		8.50%
Common units issued | shares	2,011,380
Western Gas Partners, LP [Member] | Incentive Distribution Rights [Member]
General partner's interest	100.00%	100.00%
Western Gas Partners, LP [Member] | General Partner [Member]
Percentage ownership interest	100.00%
Western Gas Partners, LP [Member] | Common Units [Member]
Ownership interest	31.50%	34.60%
Western Gas Partners, LP [Member] | Common Units [Member] | Public [Member]
Ownership interest	49.40%	55.10%
Western Gas Partners, LP [Member] | Affiliates [Member]
Note receivable - Anadarko	$ 260,000,000			$ 260,000,000
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.

Acquisitions and Divestitures -

Acquisitions and Divestitures - Acquisitions Table (Details) - USD ($) $ in Thousands		Mar. 14, 2016		Mar. 02, 2015	Mar. 31, 2016
Revolving Credit Facility [Member] | WGP RCF [Member]
Business Acquisition [Line Items]
Borrowings		$ 25,000			$ 28,000
Western Gas Partners, LP [Member]
Business Acquisition [Line Items]
Units issued					323,584
Western Gas Partners, LP [Member] | Revolving Credit Facility [Member] | WES RCF [Member]
Business Acquisition [Line Items]
Borrowings					$ 330,000
Western Gas Partners, LP [Member] | Delaware Basin JV Gathering LLC [Member]
Business Acquisition [Line Items]
Percentage acquired	[1]			100.00%
Western Gas Partners, LP [Member] | Delaware Basin JV Gathering LLC [Member] | Delaware Basin JV Gathering System [Member]
Business Acquisition [Line Items]
Percentage acquired				50.00%
Western Gas Partners, LP [Member] | Delaware Basin JV Gathering LLC [Member] | Deferred Purchase Price Obligation - Anadarko [Member] | Level 3 Inputs [Member]
Business Acquisition [Line Items]
Deferred purchase price obligation to Anadarko - acquisition date value	[1]			$ 174,276
Deferred purchase price obligation to Anadarko - future value				$ 282,800
Western Gas Partners, LP [Member] | Springfield Pipeline LLC [Member]
Business Acquisition [Line Items]
Percentage acquired	[2]	100.00%
Acquisition price		$ 750,000
Western Gas Partners, LP [Member] | Springfield Pipeline LLC [Member] | Anadarko [Member]
Business Acquisition [Line Items]
Cash payment for acquisition		$ 712,500
Western Gas Partners, LP [Member] | Springfield Pipeline LLC [Member] | Common Units [Member]
Business Acquisition [Line Items]
Units issued		2,089,602	[2]		835,841
Western Gas Partners, LP [Member] | Springfield Pipeline LLC [Member] | Common Units [Member] | Anadarko [Member]
Business Acquisition [Line Items]
Units issued		1,253,761
Western Gas Partners, LP [Member] | Springfield Pipeline LLC [Member] | Common Units [Member] | Western Gas Equity Partners, LP [Member]
Business Acquisition [Line Items]
Units issued		835,841
Western Gas Partners, LP [Member] | Springfield Pipeline LLC [Member] | Series A Preferred Units [Member]
Business Acquisition [Line Items]
Units issued	[2]	14,030,611
Western Gas Partners, LP [Member] | Springfield Pipeline LLC [Member] | Springfield System [Member]
Business Acquisition [Line Items]
Percentage acquired		50.10%
Western Gas Partners, LP [Member] | Springfield Pipeline LLC [Member] | Revolving Credit Facility [Member] | WES RCF [Member]
Business Acquisition [Line Items]
Borrowings	[2]	$ 247,500
[1]	WES acquired Delaware Basin JV Gathering LLC (“DBJV”) from Anadarko. DBJV owns a 50% interest in a gathering system and related facilities, such interest being referred to in this report as the “DBJV system”. The DBJV gathering system and related facilities are located in the Delaware Basin in Loving, Ward, Winkler and Reeves Counties, Texas. WES will make a cash payment on March 31, 2020, to Anadarko as consideration for the acquisition of DBJV. WES currently estimates the future payment will be $282.8 million, the net present value of which was $174.3 million as of the acquisition date. See DBJV acquisition—deferred purchase price obligation - Anadarko below.
[2]	WES 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 WES 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 system.” The Springfield oil and gas gathering systems are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. WES financed the cash portion of the acquisition through: (i) borrowings of $247.5 million on the WES RCF, (ii) the issuance of 835,841 of WES common units to WGP and (iii) the issuance of WES Series A Preferred units noted above to private investors (the “initial issuance”). See Note 4 for further information regarding the WES Series A Preferred units, including the full exercise of an option granted in connection with the initial issuance. WGP financed the purchase of the WES common units by borrowing $25.0 million on the WGP RCF. See Note 9.

Acquisitions and Divestitures33

Acquisitions and Divestitures - Impact to Historical Consolidated Statements of Income Table (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenues and other		$ 383,141	$ 437,006	[1]
Equity income, net	[2],[3],[4]	16,814	18,220	[1]
Net income (loss)		$ 117,759	(154,095)	[1]
Springfield Pipeline LLC [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenues and other			48,614
Equity income, net			0
Net income (loss)			23,297
Springfield Pipeline LLC [Member] | Eliminations [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenues and other			(17)
Equity income, net			0
Net income (loss)			0
WGP Historical [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenues and other			388,409
Equity income, net			18,220
Net income (loss)			$ (177,392)
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.
[2]	Income earned from equity investments is classified as affiliate. See Note 1.
[3]	Income earned on, distributions from and contributions to equity investments are classified as affiliate. See Note 1.
[4]	Represents amounts earned or incurred on and subsequent to the date of acquisition of WES assets, as well as amounts earned or incurred by Anadarko on a historical basis related to WES assets prior to the acquisition of such assets by WES, recognized under gathering, treating or processing agreements, and purchase and sale agreements.

Acquisitions and Divestitures34

Acquisitions and Divestitures - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015		Mar. 02, 2015
Property, Plant and Equipment [Line Items]
Deferred purchase price obligation - Anadarko	[1]	$ 193,211		$ 188,674	[2]
Western Gas Partners, LP [Member] | Delaware Basin JV Gathering LLC [Member] | Deferred Purchase Price Obligation - Anadarko [Member]
Property, Plant and Equipment [Line Items]
Discount rate percentage		10.00%
Deferred purchase price obligation - Anadarko		$ 193,200		$ 188,700
Interest expense, related party		$ 4,500	$ 1,400
Western Gas Partners, LP [Member] | Delaware Basin JV Gathering LLC [Member] | Deferred Purchase Price Obligation - Anadarko [Member] | Level 3 Inputs [Member]
Property, Plant and Equipment [Line Items]
Deferred purchase price obligation to Anadarko - future value						$ 282,800
Deferred purchase price obligation to Anadarko - acquisition date value	[3]					$ 174,276
[1]	See Note 2.
[2]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.
[3]	WES acquired Delaware Basin JV Gathering LLC (“DBJV”) from Anadarko. DBJV owns a 50% interest in a gathering system and related facilities, such interest being referred to in this report as the “DBJV system”. The DBJV gathering system and related facilities are located in the Delaware Basin in Loving, Ward, Winkler and Reeves Counties, Texas. WES will make a cash payment on March 31, 2020, to Anadarko as consideration for the acquisition of DBJV. WES currently estimates the future payment will be $282.8 million, the net present value of which was $174.3 million as of the acquisition date. See DBJV acquisition—deferred purchase price obligation - Anadarko below.

Partnership Distributions - Cas

Partnership Distributions - Cash Distributions Tables (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016		Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015
Distribution Made to Limited Partner [Line Items]
Total quarterly distribution per unit	$ 0.42375	[1]	$ 0.40375	$ 0.38125	$ 0.36375	$ 0.34250
Total quarterly cash distribution	$ 92,767	[1]	$ 88,389	$ 83,461	$ 79,630	$ 74,977
Western Gas Partners, LP [Member]
Distribution Made to Limited Partner [Line Items]
Total quarterly distribution per unit	$ 0.815	[2]	$ 0.800	$ 0.775	$ 0.750	$ 0.725
Total quarterly cash distribution	$ 158,905	[2]	$ 152,588	$ 146,160	$ 139,736	$ 133,203
[1]	On April 22, 2016, the Board of Directors of WGP GP declared a cash distribution to WGP unitholders of $0.42375 per unit, or $92.8 million in aggregate. The cash distribution is payable on May 22, 2016, to WGP unitholders of record at the close of business on May 2, 2016.
[2]	On April 22, 2016, the Board of Directors of WES GP declared a cash distribution to WES unitholders of $0.815 per unit, or $158.9 million in aggregate, including incentive distributions, but excluding distributions on WES Class C units (see WES Class C unit distributions below) and WES Series A Preferred units (see WES Series A Preferred unit distributions below). The cash distribution is payable on May 13, 2016, to WES unitholders of record at the close of business on May 2, 2016.

Partnership Distributions - Add

Partnership Distributions - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Distribution Made to Limited Partner [Line Items]
Partnership agreement day requirement of distribution of available cash	55 days
Units outstanding	218,919,380	218,919,380
Western Gas Partners, LP [Member]
Distribution Made to Limited Partner [Line Items]
Partnership agreement day requirement of distribution of available cash	45 days
Western Gas Partners, LP [Member] | Class C Units [Member]
Distribution Made to Limited Partner [Line Items]
Discount rate percentage	6.00%
PIK Class C units		323,584
Western Gas Partners, LP [Member] | 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	$ 1.9
Number of days in prorated period	18 days
Units outstanding	14,030,611

Equity and Partners' Capital -

Equity and Partners' Capital - Partnership Interests Table (Details) - Western Gas Partners, LP [Member] - shares		Mar. 14, 2016		Mar. 31, 2016
Capital Unit [Line Items]
Balance				142,571,895
Units issued				323,584
Balance				159,015,692
Springfield Pipeline LLC [Member]
Capital Unit [Line Items]
Acquisition				16,120,213
Common Units [Member]
Capital Unit [Line Items]
Balance				128,576,965
Balance				130,666,567
Common Units [Member] | Springfield Pipeline LLC [Member]
Capital Unit [Line Items]
Units issued		2,089,602	[1]	835,841
Acquisition				2,089,602
Class C Units [Member]
Capital Unit [Line Items]
Balance				11,411,862
Units issued				323,584
Balance				11,735,446
Series A Preferred Units [Member]
Capital Unit [Line Items]
Balance				0
Balance				14,030,611
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]	WES 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 WES 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 system.” The Springfield oil and gas gathering systems are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. WES financed the cash portion of the acquisition through: (i) borrowings of $247.5 million on the WES RCF, (ii) the issuance of 835,841 of WES common units to WGP and (iii) the issuance of WES Series A Preferred units noted above to private investors (the “initial issuance”). See Note 4 for further information regarding the WES Series A Preferred units, including the full exercise of an option granted in connection with the initial issuance. WGP financed the purchase of the WES common units by borrowing $25.0 million on the WGP RCF. See Note 9.

Equity and Partners' Capital 38

Equity and Partners' Capital - Additional Information (Details) $ / shares in Units, $ in Thousands	Mar. 14, 2016USD ($)$ / sharesshares	Apr. 30, 2016USD ($)shares	Jun. 30, 2015$ / unitshares	Nov. 30, 2014USD ($)$ / sharesshares	Mar. 31, 2016USD ($)$ / sharesshares	Mar. 31, 2015USD ($)	[1]	Dec. 31, 2015USD ($)$ / sharesshares	Aug. 31, 2014USD ($)
Schedule of Investments [Line Items]
Limited partner units owned					218,919,380			218,919,380
Anadarko [Member]
Schedule of Investments [Line Items]
Limited partner units owned					191,087,365
Ownership interest					87.30%
Anadarko [Member] | 7.50% Tangible Equity Units [Member]
Schedule of Investments [Line Items]
Tangible equity units issued			9,200,000
Tangible equity unit rate			7.50%
Stated amount per tangible equity unit | $ / unit			50
Debt instrument, maturity date			Jun. 7, 2018
Anadarko [Member] | 7.50% Tangible Equity Units [Member] | Option on Securities [Member]
Schedule of Investments [Line Items]
Tangible equity units issued			1,200,000
Anadarko [Member] | Common Units [Member]
Schedule of Investments [Line Items]
Common units issued			2,300,000
Anadarko [Member] | Common Units [Member] | Option on Securities [Member]
Schedule of Investments [Line Items]
Common units issued			300,000
Public [Member]
Schedule of Investments [Line Items]
Limited partner units owned					27,832,015
Ownership interest					12.70%
Western Gas Partners, LP [Member]
Schedule of Investments [Line Items]
General partner units owned					2,583,068
General partner's interest					1.60%			1.80%
Units issued					323,584
Western Gas Partners, LP [Member] | 500 Million COP [Member]
Schedule of Investments [Line Items]
Maximum aggregate principal of common units | $									$ 500,000
Average price per unit | $ / shares								$ 66.61
Net proceeds to WES | $								$ 57,400
Underwriting discount and other offering expenses | $								800
Gross proceeds | $								58,200
Commissions paid | $								$ 600
Western Gas Partners, LP [Member] | Class C Units [Member]
Schedule of Investments [Line Items]
Units issued					323,584
Price per unit | $ / shares				$ 68.72
Proceeds from the issuance of WES units | $				$ 750,000
Western Gas Partners, LP [Member] | Class C Units [Member] | Maximum [Member]
Schedule of Investments [Line Items]
Redeemable option on units | $				$ 150,000
Western Gas Partners, LP [Member] | Series A Preferred Units [Member]
Schedule of Investments [Line Items]
Limited partner units owned					14,030,611
Price per unit | $ / shares	$ 32
Proceeds from the issuance of WES units | $	$ 440,000				$ 440,000	$ 0
Transaction fee	2.00%
Series A Preferred units, units issued upon conversion					1
Minimum common unit closing price for conversion | $ / shares					$ 48
Redemption price per unit | $ / shares					$ 32.32
Western Gas Partners, LP [Member] | Series A Preferred Units [Member] | Subsequent Event [Member]
Schedule of Investments [Line Items]
Proceeds from the issuance of WES units | $		$ 247,500
Western Gas Partners, LP [Member] | Common Units [Member]
Schedule of Investments [Line Items]
Limited partner units owned					50,132,046
Ownership interest					31.50%			34.60%
Western Gas Partners, LP [Member] | Common Units [Member] | 500 Million COP [Member]
Schedule of Investments [Line Items]
Common units issued					0			873,525
Western Gas Partners, LP [Member] | Incentive Distribution Rights [Member]
Schedule of Investments [Line Items]
General partner's interest					100.00%			100.00%
Western Gas Partners, LP [Member] | Private investor [Member] | Series A Preferred Units [Member]
Schedule of Investments [Line Items]
Limited partner units owned					14,030,611
Ownership interest					8.80%
Units issued	14,030,611
Western Gas Partners, LP [Member] | Private investor [Member] | Series A Preferred Units [Member] | Subsequent Event [Member] | Option on Securities [Member]
Schedule of Investments [Line Items]
Units issued		7,892,220
Western Gas Partners, LP [Member] | Public [Member] | Common Units [Member]
Schedule of Investments [Line Items]
Limited partner units owned					78,523,141
Ownership interest					49.40%			55.10%
Western Gas Partners, LP [Member] | Other Subsidiaries Of Anadarko [Member]
Schedule of Investments [Line Items]
Ownership interest								8.50%
Western Gas Partners, LP [Member] | Other Subsidiaries Of Anadarko [Member] | Class C Units [Member]
Schedule of Investments [Line Items]
Limited partner units owned					11,735,446
Units issued				10,913,853
Western Gas Partners, LP [Member] | Other Subsidiaries Of Anadarko [Member] | Common Units [Member]
Schedule of Investments [Line Items]
Limited partner units owned					2,011,380
Western Gas Partners, LP [Member] | Other Subsidiaries Of Anadarko [Member] | Common and Class C Units [Member]
Schedule of Investments [Line Items]
Ownership interest					8.70%
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.

Transactions with Affiliates -

Transactions with Affiliates - Commodity Price Swap Agreements Table (Details) - Western Gas Partners, LP [Member] - Year 2016 [Member]	Mar. 31, 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 40

Transactions with Affiliates - Gains (Losses) on Commodity Price Swap Agreements Table (Details) - Western Gas Partners, LP [Member] - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements		$ 8,240	$ 21,235
Sales [Member]
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements	[1]	27,111	55,414
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]	7,041	10,982
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]	20,070	44,432
Purchases [Member]
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements	[2]	$ (18,871)	$ (34,179)
[1]	Reported in affiliate Natural gas and natural gas liquids sales in the consolidated statements of income in the period in which the related sale is recorded.
[2]	Reported in Cost of product in the consolidated statements of income in the period in which the related purchase is recorded.

Transactions with Affiliates 41

Transactions with Affiliates - Commodity Price Swap Agreements Extensions Tables (Details) - Western Gas Partners, LP [Member]		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 42

Transactions with Affiliates - Equipment Purchases and Sales Table (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015		Dec. 31, 2015	[1]
Related Party Transaction [Line Items]
Payable to affiliate	$ 103,754			$ 98,661
Partners’ capital adjustment	714	$ 205	[2]
Western Gas Partners, LP [Member] | Affiliates [Member] | Purchases [Member]
Related Party Transaction [Line Items]
Cash consideration - purchases	1,096	765
Payable to affiliate	990	0
Net carrying value	1,372	560
Partners’ capital adjustment	$ 714	$ 205
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.
[2]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.

Transactions with Affiliates 43

Transactions with Affiliates - Summary of Affiliate Transactions Table (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Related Party Transaction [Line Items]
Revenues and other		$ 383,141	$ 437,006	[1]
Equity income, net	[2],[3],[4]	16,814	18,220	[1]
Cost of product	[5]	76,467	139,408	[1]
Operation and maintenance	[5]	76,213	76,185	[1]
General and administrative	[5]	12,515	11,916	[1]
Operating expenses		247,158	578,388	[1]
Interest income	[6]	4,225	4,225	[1]
Interest expense	[7]	32,139	22,962	[1]
Distributions to unitholders	[8]	88,389	68,409	[1]
Above-market component of swap extensions with Anadarko	[8]	6,813	0	[1]
Affiliates [Member]
Related Party Transaction [Line Items]
Revenues and other	[4]	272,584	306,928	[1]
Cost of product	[4]	24,580	43,895
Operation and maintenance	[9]	17,975	16,817
General and administrative	[10]	9,150	8,335
Operating expenses		51,705	69,047
Interest expense	[11]	4,537	1,422
Affiliates [Member] | Western Gas Equity Partners, LP [Member]
Related Party Transaction [Line Items]
Distributions to unitholders	[12]	77,152	60,434
Affiliates [Member] | Western Gas Partners, LP [Member]
Related Party Transaction [Line Items]
Distributions to unitholders	[13]	$ 606	$ 530
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.
[2]	Income earned from equity investments is classified as affiliate. See Note 1.
[3]	Income earned on, distributions from and contributions to equity investments are classified as affiliate. See Note 1.
[4]	Represents amounts earned or incurred on and subsequent to the date of acquisition of WES assets, as well as amounts earned or incurred by Anadarko on a historical basis related to WES assets prior to the acquisition of such assets by WES, recognized under gathering, treating or processing agreements, and purchase and sale agreements.
[5]	Cost of product includes product purchases from Anadarko (as defined in Note 1) of $24.6 million and $43.9 million for the three months ended March 31, 2016 and 2015, respectively. Operation and maintenance includes charges from Anadarko of $18.0 million and $16.8 million for the three months ended March 31, 2016 and 2015, respectively. General and administrative includes charges from Anadarko of $9.2 million and $8.3 million for the three months ended March 31, 2016 and 2015, respectively. See Note 5.
[6]	Represents interest income recognized on the note receivable from Anadarko.
[7]	Includes affiliate (as defined in Note 1) interest expense of $4.5 million and $1.4 million for the three months ended March 31, 2016 and 2015, respectively. See Note 2 and Note 9.
[8]	See Note 5.
[9]	Represents expenses incurred on and subsequent to the date of the acquisition of WES assets, as well as expenses incurred by Anadarko on a historical basis related to WES assets prior to the acquisition of such assets by WES.
[10]	Represents general and administrative expense incurred on and subsequent to the date of WES’s acquisition of WES assets, as well as a management services fee for reimbursement of expenses incurred by Anadarko for periods prior to the acquisition of WES assets by WES. These amounts include equity-based compensation expense allocated to WES and WGP by Anadarko (see WES LTIP and WGP LTIP and Anadarko Incentive Plans within this Note 5) and amounts charged by Anadarko under the WGP omnibus agreement.
[11]	For the three months ended March 31, 2016 and 2015, includes WES’s accretion expense recognized on the Deferred purchase price obligation - Anadarko for the acquisition of DBJV (see Note 2 and Note 9) and for the three months ended March 31, 2015, includes interest expense recognized on the WGP WCF (see Note 9).
[12]	Represents distributions paid under WGP’s partnership agreement (see Note 3 and Note 4).
[13]	Represents distributions paid to other subsidiaries of Anadarko under WES’s partnership agreement (see Note 3 and Note 4).

Transactions with Affiliates 44

Transactions with Affiliates - Additional Information (Details) - USD ($)		1 Months Ended	3 Months Ended
		May. 31, 2008	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015		Nov. 01, 2012
Related Party Transaction [Line Items]
Note receivable - Anadarko			$ 260,000,000		$ 260,000,000	[1]
Above-market component of swap extensions with Anadarko	[2]		6,813,000
Contributions of equity-based compensation to WES by Anadarko			$ 1,051,000
Western Gas Equity Partners Long Term Incentive Plan [Member]
Related Party Transaction [Line Items]
Units vesting period			3 years
Equity-based compensation expense			$ 56,000	$ 55,000
Western Gas Partners, LP [Member] | Western Gas Equity Partners Long Term Incentive Plan [Member] | Anadarko Incentive Plans [Member]
Related Party Transaction [Line Items]
Equity-based compensation expense			1,200,000	1,000,000
Contributions of equity-based compensation to WES by Anadarko			$ 1,100,000
Western Gas Partners, LP [Member] | 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
Western Gas Partners, LP [Member] | Natural Gas [Member] | Gathering, Treating and Transportation [Member]
Related Party Transaction [Line Items]
Affiliate throughput percent			37.00%	56.00%
Western Gas Partners, LP [Member] | Natural Gas [Member] | Processing [Member]
Related Party Transaction [Line Items]
Affiliate throughput percent			61.00%	52.00%
Western Gas Partners, LP [Member] | Crude Oil and NGL [Member] | Gathering, Treating and Transportation [Member]
Related Party Transaction [Line Items]
Affiliate throughput percent			64.00%	100.00%
Affiliates [Member] | Working Capital Facility [Member]
Related Party Transaction [Line Items]
Facility, maximum borrowing capacity							$ 30,000,000
Facility, expiration date			Nov. 1, 2017
Affiliates [Member] | Working Capital Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Related Party Transaction [Line Items]
Interest rate percent above LIBOR			1.50%
Affiliates [Member] | Western Gas Partners, LP [Member]
Related Party Transaction [Line Items]
Note receivable - Anadarko		$ 260,000,000	$ 260,000,000
Note receivable, due date		May 14, 2038
Fixed annual rate for note receivable bearing interest		6.50%
Affiliates [Member] | Western Gas Partners, LP [Member] | Level 2 Inputs [Member] | Market Approach Valuation Technique [Member]
Related Party Transaction [Line Items]
Fair value of the note receivable			$ 260,400,000		$ 252,300,000
Independent Director [Member] | Western Gas Equity Partners Long Term Incentive Plan [Member]
Related Party Transaction [Line Items]
Units vesting period			1 year
Independent Director [Member] | Western Gas Partners, LP [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 system. 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	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 6,700,809	$ 6,556,778	[1]
Accumulated depreciation	1,760,590	1,697,999	[1]
Net property, plant and equipment	4,940,219	4,858,779	[1]
Western Gas Partners, LP [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	3,946	3,744
Western Gas Partners, LP [Member] | Gathering Systems [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 6,160,896	6,061,004
Western Gas Partners, LP [Member] | Gathering Systems [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Western Gas Partners, LP [Member] | Gathering Systems [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	47 years
Western Gas Partners, LP [Member] | Pipelines and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 136,263	136,290
Western Gas Partners, LP [Member] | Pipelines and Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	15 years
Western Gas Partners, LP [Member] | Pipelines and Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	45 years
Western Gas Partners, LP [Member] | Assets Under Construction [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 371,358	329,887
Western Gas Partners, LP [Member] | Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 28,346	$ 25,853
Western Gas Partners, LP [Member] | Other [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Western Gas Partners, LP [Member] | 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 system. See Note 1 and Note 2.

Property, Plant and Equipment46

Property, Plant and Equipment - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	[1]
Property, Plant and Equipment [Line Items]
Impairments	$ 6,518	$ 272,624
Western Gas Partners, LP [Member] | Newcastle System [Member]
Property, Plant and Equipment [Line Items]
Impairments	6,200
Western Gas Partners, LP [Member] | 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
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.

Equity Investments - Equity Inv

Equity Investments - Equity Investments Table (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016		Mar. 31, 2015	[5]
Schedule of Equity Method Investments [Line Items]
Balance	[1]	$ 618,887
Investment earnings (loss), net of amortization	[2],[3],[4]	16,814		$ 18,220
Contributions		(474)		4,878
Distributions	[3]	(19,855)		(18,706)
Distributions in excess of cumulative earnings	[3]	(4,784)	[6]	$ (2,964)
Balance		610,588
Fort Union [Member] | Western Gas Partners, LP [Member]
Schedule of Equity Method Investments [Line Items]
Balance		17,122
Investment earnings (loss), net of amortization		(2,192)
Contributions		0
Distributions		0
Distributions in excess of cumulative earnings	[6]	(783)
Balance		14,147
White Cliffs [Member] | Western Gas Partners, LP [Member]
Schedule of Equity Method Investments [Line Items]
Balance		50,439
Investment earnings (loss), net of amortization		3,993
Contributions		106
Distributions		(3,848)
Distributions in excess of cumulative earnings	[6]	(877)
Balance		49,813
Rendezvous [Member] | Western Gas Partners, LP [Member]
Schedule of Equity Method Investments [Line Items]
Balance		50,913
Investment earnings (loss), net of amortization		550
Contributions		0
Distributions		(1,036)
Distributions in excess of cumulative earnings	[6]	(1,541)
Balance		48,886
Mont Belvieu JV [Member] | Western Gas Partners, LP [Member]
Schedule of Equity Method Investments [Line Items]
Balance		117,089
Investment earnings (loss), net of amortization		5,419
Contributions		0
Distributions		(5,428)
Distributions in excess of cumulative earnings	[6]	(172)
Balance		116,908
Texas Express Gathering LLC [Member] | Western Gas Partners, LP [Member]
Schedule of Equity Method Investments [Line Items]
Balance		16,283
Investment earnings (loss), net of amortization		257
Contributions		0
Distributions		(262)
Distributions in excess of cumulative earnings	[6]	(21)
Balance		16,257
Texas Express Pipeline LLC [Member] | Western Gas Partners, LP [Member]
Schedule of Equity Method Investments [Line Items]
Balance		194,803
Investment earnings (loss), net of amortization		4,097
Contributions		(580)
Distributions		(4,160)
Distributions in excess of cumulative earnings	[6]	(1,390)
Balance		192,770
Front Range Pipeline LLC [Member] | Western Gas Partners, LP [Member]
Schedule of Equity Method Investments [Line Items]
Balance		172,238
Investment earnings (loss), net of amortization		4,690
Contributions		0
Distributions		(5,121)
Distributions in excess of cumulative earnings	[6]	0
Balance		$ 171,807
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.
[2]	Income earned from equity investments is classified as affiliate. See Note 1.
[3]	Income earned on, distributions from and contributions to equity investments are classified as affiliate. See Note 1.
[4]	Represents amounts earned or incurred on and subsequent to the date of acquisition of WES assets, as well as amounts earned or incurred by Anadarko on a historical basis related to WES assets prior to the acquisition of such assets by WES, recognized under gathering, treating or processing agreements, and purchase and sale agreements.
[5]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.
[6]	Distributions in excess of cumulative earnings, classified as investing cash flows in the consolidated statements of cash flows, is calculated on an individual investment basis.

Equity Investments - Additional

Equity Investments - Additional Information (Details) - Western Gas Partners, LP [Member] - Fort Union [Member] $ in Millions	3 Months Ended
	Mar. 31, 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 WES exercises significant influence are accounted for under the equity method. “Equity investment throughput” refers to WES’s share of average throughput for these investments.

Components of Working Capital -

Components of Working Capital - Accounts Receivable, Net Table (Details) - USD ($) $ in Thousands		Mar. 31, 2016	Dec. 31, 2015
Receivables [Abstract]
Trade receivables, net		$ 130,559	$ 143,341
Other receivables, net		49,042	49,772
Total accounts receivable, net	[1]	$ 179,601	$ 193,113	[2]
[1]	Accounts receivable, net includes amounts receivable from affiliates (as defined in Note 1) of $53.6 million and $42.5 million as of March 31, 2016, and December 31, 2015, respectively. Accounts receivable, net as of March 31, 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 system. See Note 1 and Note 2.

Components of Working Capital50

Components of Working Capital - Other Current Assets Table (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Other Current Assets [Line Items]
Natural gas liquids inventory	$ 832	$ 2,403
Imbalance receivables	1,425	2,122
Prepaid insurance	1,807	2,998
Other	0	1,034
Total other current assets	$ 4,064	$ 8,557	[1]
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.

Components of Working Capital51

Components of Working Capital - Accrued Liabilities Table (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Accrued Liabilities [Line Items]
Accrued interest expense	$ 34,578	$ 26,194
Short-term asset retirement obligations	2,909	3,677
Short-term remediation and reclamation obligations	1,136	1,136
Income taxes payable	931	770
Total accrued liabilities	128,380	119,096	[1]
Accrued Capital Expenditures [Member]
Accrued Liabilities [Line Items]
Other accrued liabilities	68,152	61,454
Accrued Plant Purchases [Member]
Accrued Liabilities [Line Items]
Other accrued liabilities	15,885	16,425
Other Accrued Liabilities [Member]
Accrued Liabilities [Line Items]
Other accrued liabilities	$ 4,789	$ 9,440
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.

Debt and Interest Expense - Deb

Debt and Interest Expense - Debt Outstanding Table (Details) - USD ($)		Mar. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Total long-term debt principal		$ 3,078,000,000	$ 2,720,000,000
Carrying value		3,049,325,000	2,690,651,000	[1]
Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[2]	2,808,729,000	2,492,466,000
WGP RCF [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Principal		28,000,000	0
Carrying value		28,000,000	0
WGP RCF [Member] | Revolving Credit Facility [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[2]	28,000,000	0
Western Gas Partners, LP [Member] | WES RCF [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Principal		630,000,000	300,000,000
Carrying value		630,000,000	300,000,000
Western Gas Partners, LP [Member] | WES RCF [Member] | Revolving Credit Facility [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[2]	630,000,000	300,000,000
Western Gas Partners, LP [Member] | Senior Notes [Member] | 5.375% Senior Notes due 2021 [Member]
Debt Instrument [Line Items]
Principal		500,000,000	500,000,000
Carrying value		493,962,000	493,711,000
Western Gas Partners, LP [Member] | 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]	480,315,000	513,645,000
Western Gas Partners, LP [Member] | Senior Notes [Member] | 4.000% Senior Notes due 2022 [Member]
Debt Instrument [Line Items]
Principal		670,000,000	670,000,000
Carrying value		668,482,000	668,432,000
Western Gas Partners, LP [Member] | 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]	597,975,000	595,744,000
Western Gas Partners, LP [Member] | Senior Notes [Member] | 2.600% Senior Notes due 2018 [Member]
Debt Instrument [Line Items]
Principal		350,000,000	350,000,000
Carrying value		348,826,000	348,706,000
Western Gas Partners, LP [Member] | 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]	331,187,000	339,293,000
Western Gas Partners, LP [Member] | Senior Notes [Member] | 5.450% Senior Notes due 2044 [Member]
Debt Instrument [Line Items]
Principal		400,000,000	400,000,000
Carrying value		389,744,000	389,707,000
Western Gas Partners, LP [Member] | 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]	313,752,000	321,499,000
Western Gas Partners, LP [Member] | Senior Notes [Member] | 3.950% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Principal		500,000,000	500,000,000
Carrying value		490,311,000	490,095,000
Western Gas Partners, LP [Member] | 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]	$ 427,500,000	$ 422,285,000
[1]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.
[2]	Fair value is measured using the market approach and Level 2 inputs.

Debt and Interest Expense - D53

Debt and Interest Expense - Debt Activity Table (Details) - USD ($) $ in Thousands	Mar. 14, 2016	Mar. 31, 2016
Debt Instrument [Line Items]
Beginning balance		$ 2,690,651
Ending balance		3,049,325
Revolving Credit Facility [Member] | WGP RCF [Member]
Debt Instrument [Line Items]
Borrowings	$ 25,000	28,000
Western Gas Partners, LP [Member]
Debt Instrument [Line Items]
Other		674
Western Gas Partners, LP [Member] | Revolving Credit Facility [Member] | WES RCF [Member]
Debt Instrument [Line Items]
Borrowings		$ 330,000

Debt and Interest Expense - Int

Debt and Interest Expense - Interest Expense Table (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Debt Instrument [Line Items]
Interest expense	[1]	$ 32,139	$ 22,962	[2]
Third Parties [Member]
Debt Instrument [Line Items]
Long-term debt		27,856	23,342
Amortization of debt issuance costs and commitment fees		1,595	1,292
Capitalized interest		(1,849)	(3,094)
Interest expense		27,602	21,540
Affiliates [Member]
Debt Instrument [Line Items]
Interest expense	[3]	4,537	1,422
Affiliates [Member] | Deferred Purchase Price Obligation - Anadarko [Member]
Debt Instrument [Line Items]
Interest expense, related party	[4]	4,537	1,420
Affiliates [Member] | Working Capital Facility [Member]
Debt Instrument [Line Items]
Interest expense, related party		$ 0	$ 2
[1]	Includes affiliate (as defined in Note 1) interest expense of $4.5 million and $1.4 million for the three months ended March 31, 2016 and 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 system. See Note 1 and Note 2.
[3]	For the three months ended March 31, 2016 and 2015, includes WES’s accretion expense recognized on the Deferred purchase price obligation - Anadarko for the acquisition of DBJV (see Note 2 and Note 9) and for the three months ended March 31, 2015, includes interest expense recognized on the WGP WCF (see 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 ($)		Mar. 14, 2016		Apr. 30, 2016	Mar. 31, 2016	Mar. 31, 2015		Nov. 01, 2012
Working Capital Facility [Member] | Affiliates [Member]
Debt Instrument [Line Items]
Facility, maximum borrowing capacity								$ 30,000,000
Facility, interest rate at period end					1.94%	1.68%
Facility, outstanding borrowings					$ 0
Facility, available borrowing capacity					$ 30,000,000
Facility, expiration date					Nov. 1, 2017
Working Capital Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Affiliates [Member]
Debt Instrument [Line Items]
Applicable margin added					1.50%
WGP RCF [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility, maximum borrowing capacity					$ 250,000,000
Facility, expandable maximum borrowing capacity					500,000,000
Borrowings		$ 25,000,000			$ 28,000,000
Facility, interest rate at period end					2.69%
Facility, fee rate					0.30%
Facility, outstanding borrowings					$ 28,000,000
Facility, available borrowing capacity					$ 222,000,000
Facility, expiration date					Mar. 14, 2019
WGP RCF [Member] | Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt instrument, variable rate floor					0.00%
WGP RCF [Member] | Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Alternate Base Rate [Member]
Debt Instrument [Line Items]
Applicable margin added					1.00%
WGP RCF [Member] | Revolving Credit Facility [Member] | Percentage Above Federal Funds Effective Rate [Member] | Alternate Base Rate [Member]
Debt Instrument [Line Items]
Applicable margin added					0.50%
WGP RCF [Member] | Revolving Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Facility, fee rate					0.30%
WGP RCF [Member] | Revolving Credit Facility [Member] | Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Applicable margin added					2.00%
WGP RCF [Member] | Revolving Credit Facility [Member] | Minimum [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Applicable margin added					1.00%
WGP RCF [Member] | Revolving Credit Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Facility, fee rate					0.50%
WGP RCF [Member] | Revolving Credit Facility [Member] | Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Applicable margin added					2.75%
WGP RCF [Member] | Revolving Credit Facility [Member] | Maximum [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Applicable margin added					1.75%
Western Gas Partners, LP [Member]
Debt Instrument [Line Items]
Units issued					323,584
Western Gas Partners, LP [Member] | Common Units [Member] | Springfield Pipeline LLC [Member]
Debt Instrument [Line Items]
Units issued		2,089,602	[1]		835,841
Western Gas Partners, LP [Member] | Series A Preferred Units [Member]
Debt Instrument [Line Items]
Proceeds from the issuance of WES units		$ 440,000,000			$ 440,000,000	$ 0	[2]
Western Gas Partners, LP [Member] | Series A Preferred Units [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Proceeds from the issuance of WES units				$ 247,500,000
Western Gas Partners, LP [Member] | Series A Preferred Units [Member] | Springfield Pipeline LLC [Member]
Debt Instrument [Line Items]
Units issued	[1]	14,030,611
Western Gas Partners, LP [Member] | WES RCF [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Borrowings					$ 330,000,000
Facility, interest rate at period end					1.74%	1.48%
Facility, fee rate					0.20%	0.20%
Facility, outstanding borrowings					$ 630,000,000
Outstanding letters of credit					4,900,000
Facility, available borrowing capacity					$ 565,100,000
Facility, expiration date					Feb. 26, 2019
Western Gas Partners, LP [Member] | WES RCF [Member] | Revolving Credit Facility [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Repayment				$ 250,000,000
Western Gas Partners, LP [Member] | WES RCF [Member] | Revolving Credit Facility [Member] | Springfield Pipeline LLC [Member]
Debt Instrument [Line Items]
Borrowings	[1]	$ 247,500,000
Western Gas Partners, LP [Member] | 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
Western Gas Partners, LP [Member] | 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
Western Gas Partners, LP [Member] | 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
Western Gas Partners, LP [Member] | 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
Western Gas Partners, LP [Member] | 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
[1]	WES 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 WES 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 system.” The Springfield oil and gas gathering systems are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. WES financed the cash portion of the acquisition through: (i) borrowings of $247.5 million on the WES RCF, (ii) the issuance of 835,841 of WES common units to WGP and (iii) the issuance of WES Series A Preferred units noted above to private investors (the “initial issuance”). See Note 4 for further information regarding the WES Series A Preferred units, including the full exercise of an option granted in connection with the initial issuance. WGP financed the purchase of the WES common units by borrowing $25.0 million on the WGP RCF. See Note 9.
[2]	Financial information has been recast to include the financial position and results attributable to the Springfield system. See Note 1 and Note 2.

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - Western Gas Partners, LP [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Loss Contingencies [Line Items]
Committed capital	$ 90
Rent expense associated with office, warehouse and equipment leases	$ 8.9	$ 8