Western Midstream Partners (WES) 10-Q 3 May 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2017	May 01, 2017
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, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Units Outstanding		218,928,570

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Revenues and Other
Total revenues and other		$ 516,193	$ 383,141
Equity income, net – affiliates	[1]	19,461	16,814
Operating expenses
Cost of product	[2]	189,359	76,467
Operation and maintenance	[2]	73,760	76,213
General and administrative	[2]	13,476	12,515
Property and other taxes		12,294	10,350
Depreciation and amortization		69,702	65,095
Impairments		164,742	6,518
Total operating expenses		523,333	247,158
Gain (loss) on divestiture and other, net		119,487	(632)
Proceeds from business interruption insurance claims		5,767	0
Operating income (loss)		137,575	152,165
Interest income – affiliates	[3]	4,225	4,225
Interest expense	[4]	(36,033)	(32,139)
Other income (expense), net		446	141
Income (loss) before income taxes		106,213	124,392
Income tax (benefit) expense		3,552	6,633
Net income (loss)		102,661	117,759
Net income (loss) attributable to noncontrolling interests		26,721	35,943
Net income (loss) attributable to Western Gas Equity Partners, LP		75,940	81,816
Limited partners' interest in net income (loss):
Pre-acquisition net (income) loss allocated to Anadarko		0	(11,326)
Limited partners' interest in net income (loss)	[5]	75,940	70,490
Affiliates [Member]
Revenues and Other
Gathering, processing and transportation		172,314	187,718
Natural gas and natural gas liquids sales		142,841	84,866
Total revenues and other	[1]	315,155	272,584
Operating expenses
Cost of product	[1]	15,988	24,580
Operation and maintenance	[6]	17,089	17,975
General and administrative	[7]	9,734	9,150
Total operating expenses		42,811	51,705
Interest expense	[8]	(71)	(4,537)
Third Parties [Member]
Revenues and Other
Gathering, processing and transportation		135,500	106,286
Natural gas and natural gas liquids sales		63,684	3,690
Other		1,854	581
Total revenues and other		201,038	110,557
Operating expenses
Interest expense		$ (35,962)	$ (27,602)
Limited Partner [Member]
Limited partners' interest in net income (loss):
Net income (loss) per common unit - basic and diluted		$ 0.35	$ 0.32
Weighted-average common units outstanding - basic and diluted		218,929	218,919
[1]	Represents amounts earned or incurred on and subsequent to the date of the 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]	Cost of product includes product purchases from Anadarko (as defined in Note 1) of $16.0 million and $24.6 million for the three months ended March 31, 2017 and 2016, respectively. Operation and maintenance includes charges from Anadarko of $17.1 million and $18.0 million for the three months ended March 31, 2017 and 2016, respectively. General and administrative includes charges from Anadarko of $9.7 million and $9.2 million for the three months ended March 31, 2017 and 2016, respectively. See Note 5.
[3]	Represents interest income recognized on the note receivable from Anadarko.
[4]	Includes affiliate (as defined in Note 1) amounts of $(0.1) million and $(4.5) million for the three months ended March 31, 2017 and 2016, respectively. See Note 2 and Note 9.
[5]	Represents net income (loss) earned on and subsequent to the date of acquisition of WES assets (as defined in Note 1). See Note 4.
[6]	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.
[7]	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 Plan within this Note 5) and amounts charged by Anadarko under the WGP and WES omnibus agreements.
[8]	Includes amounts related to WES’s Deferred purchase price obligation - Anadarko (see Note 2 and Note 9).

Consolidated Statements of Ope3

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Cost of product	[1]	$ 189,359	$ 76,467
Operation and maintenance	[1]	73,760	76,213
General and administrative	[1]	13,476	12,515
Interest expense	[2]	(36,033)	(32,139)
Affiliates [Member]
Cost of product	[3]	15,988	24,580
Operation and maintenance	[4]	17,089	17,975
General and administrative	[5]	9,734	9,150
Interest expense	[6]	$ (71)	$ (4,537)
[1]	Cost of product includes product purchases from Anadarko (as defined in Note 1) of $16.0 million and $24.6 million for the three months ended March 31, 2017 and 2016, respectively. Operation and maintenance includes charges from Anadarko of $17.1 million and $18.0 million for the three months ended March 31, 2017 and 2016, respectively. General and administrative includes charges from Anadarko of $9.7 million and $9.2 million for the three months ended March 31, 2017 and 2016, respectively. See Note 5.
[2]	Includes affiliate (as defined in Note 1) amounts of $(0.1) million and $(4.5) million for the three months ended March 31, 2017 and 2016, respectively. See Note 2 and Note 9.
[3]	Represents amounts earned or incurred on and subsequent to the date of the 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.
[4]	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.
[5]	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 Plan within this Note 5) and amounts charged by Anadarko under the WGP and WES omnibus agreements.
[6]	Includes amounts related to WES’s Deferred purchase price obligation - Anadarko (see Note 2 and Note 9).

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents		$ 122,653	$ 359,072
Accounts receivable, net	[1]	152,544	223,021
Other current assets		11,038	13,498
Total current assets		286,235	595,591
Note receivable - Anadarko		260,000	260,000
Property, plant and equipment
Cost		7,240,894	6,861,942
Less accumulated depreciation		1,974,081	1,812,010
Net property, plant and equipment		5,266,813	5,049,932
Goodwill		417,610	417,610
Other intangible assets		796,591	803,698
Equity investments		591,102	594,208
Other assets		16,431	15,058
Total assets		7,634,782	7,736,097
Current liabilities
Accounts and imbalance payables		186,882	247,076
Accrued ad valorem taxes		35,185	23,121
Accrued liabilities	[2]	58,083	45,190
Total current liabilities		280,150	315,387
Long-term debt		3,120,257	3,119,461
Deferred income taxes		9,529	6,402
Asset retirement obligations and other		145,342	142,641
Deferred purchase price obligation - Anadarko	[3]	37,346	41,440
Total long-term liabilities		3,312,474	3,309,944
Total liabilities		3,592,624	3,625,331
Equity and partners' capital
Common units (218,928,570 units issued and outstanding at March 31, 2017, and December 31, 2016)		1,042,403	1,048,143
Total partners' capital		1,042,403	1,048,143
Noncontrolling interests		2,999,755	3,062,623
Total equity and partners' capital		4,042,158	4,110,766
Total liabilities, equity and partners' capital		$ 7,634,782	$ 7,736,097
[1]	Accounts receivable, net includes amounts receivable from affiliates (as defined in Note 1) of $60.2 million and $76.4 million as of March 31, 2017, and December 31, 2016, respectively. Accounts receivable, net as of December 31, 2016, also includes an insurance claim receivable related to an incident at the DBM complex. See Note 1.
[2]	Accrued liabilities includes affiliate amounts of $0.4 million and zero as of March 31, 2017, and December 31, 2016, respectively.
[3]	See Note 2.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Common units issued		218,928,570	218,928,570
Common units outstanding		218,928,570	218,928,570
Accounts receivable, net	[1]	$ 152,544	$ 223,021
Accrued liabilities	[2]	58,083	45,190
Affiliates [Member]
Accounts receivable, net		60,200	76,400
Accrued liabilities		$ 400	$ 0
[1]	Accounts receivable, net includes amounts receivable from affiliates (as defined in Note 1) of $60.2 million and $76.4 million as of March 31, 2017, and December 31, 2016, respectively. Accounts receivable, net as of December 31, 2016, also includes an insurance claim receivable related to an incident at the DBM complex. See Note 1.
[2]	Accrued liabilities includes affiliate amounts of $0.4 million and zero as of March 31, 2017, and December 31, 2016, respectively.

Consolidated Statement of Equit

Consolidated Statement of Equity and Partners' Capital - 3 months ended Mar. 31, 2017 - USD ($) $ in Thousands		Total	Western Gas Partners, LP [Member]	Chipeta Processing LLC [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 LLC [Member]
Balance at Dec. 31, 2016		$ 4,110,766			$ 0	$ 1,048,143	$ 3,062,623
Net income (loss)		102,661			0	75,940	26,721
Above-market component of swap extensions with Anadarko	[1]	12,297				12,297
WES equity transactions, net	[2]	(182)				1,947	(2,129)
Distributions to noncontrolling interest owners			$ (84,172)	$ (3,370)				$ (84,172)	$ (3,370)
Distributions to WGP unitholders		(101,254)				(101,254)
Acquisitions from affiliates		0			14	(14)
Revision to Deferred purchase price obligation – Anadarko	[3]	4,165				4,165
Contributions of equity-based compensation to WES by Anadarko		1,125				1,125
Net pre-acquisition contributions from (distributions to) Anadarko		(14)			(14)
Other		136				54	82
Balance at Mar. 31, 2017		$ 4,042,158			$ 0	$ 1,042,403	$ 2,999,755
[1]	See Note 5.
[2]	Includes the impact of WES’s (as defined in Note 1) equity offerings as described in Note 4. The $1.9 million increase to partners’ capital, together with net income (loss) attributable to Western Gas Equity Partners, LP, totaled $77.9 million for the three months ended March 31, 2017.
[3]	See Note 2.

Consolidated Statement of Equi7

Consolidated Statement of Equity and Partners' Capital (Parenthetical) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)
WES equity transactions, net	$ (182)	[1]
Combined change in Partners' Capital from WES equity transactions, net and net income (loss) attributable to Western Gas Equity Partners, LP	77,900
Common Units [Member]
WES equity transactions, net	$ 1,947	[1]
[1]	Includes the impact of WES’s (as defined in Note 1) equity offerings as described in Note 4. The $1.9 million increase to partners’ capital, together with net income (loss) attributable to Western Gas Equity Partners, LP, totaled $77.9 million for the three months ended March 31, 2017.

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017		Mar. 31, 2016
Cash flows from operating activities
Net income (loss)		$ 102,661		$ 117,759
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization		69,702		65,095
Impairments		164,742		6,518
Non-cash equity-based compensation expense		1,269		1,291
Deferred income taxes		3,128		1,852
Accretion and amortization of long-term obligations, net		1,268		5,496
Equity income, net – affiliates	[1]	(19,461)		(16,814)
Distributions from equity investment earnings – affiliates		19,114		19,855
(Gain) loss on divestiture and other, net		(119,487)		632
Lower of cost or market inventory adjustments		45		0
Changes in assets and liabilities:
(Increase) decrease in accounts receivable, net		(1,530)		12,513
Increase (decrease) in accounts and imbalance payables and accrued liabilities, net		(29,935)		18,446
Change in other items, net		157		3,240
Net cash provided by operating activities		191,673		235,883
Cash flows from investing activities
Capital expenditures		(125,944)		(136,987)
Investments in equity affiliates		0		474
Distributions from equity investments in excess of cumulative earnings – affiliates		3,453	[2]	4,784
Proceeds from property insurance claims		24,000		0
Net cash used in investing activities		(252,434)		(842,818)
Cash flows from financing activities
Borrowings, net of debt issuance costs		(11)		356,162
Increase (decrease) in outstanding checks		1,024		(994)
Distributions to WGP unitholders	[3]	(101,254)		(88,389)
Net contributions from (distributions to) Anadarko		(14)		(27,632)
Above-market component of swap extensions with Anadarko	[3]	12,297		6,813
Net cash provided by (used in) financing activities		(175,658)		618,697
Net increase (decrease) in cash and cash equivalents		(236,419)		11,762
Cash and cash equivalents at beginning of period		359,072		99,694
Cash and cash equivalents at end of period		122,653		111,456
Supplemental disclosures
Net distributions to (contributions from) Anadarko of other assets		0		714
Interest paid, net of capitalized interest		29,014		18,223
Taxes paid (reimbursements received)		189		67
Accrued capital expenditures		85,280		68,152
Fair value of properties and equipment from non-cash third party transactions	[4]	548,628		0
Delaware Basin JV Gathering LLC [Member]
Supplemental disclosures
Accretion expense and revisions to the Deferred purchase price obligation – Anadarko	[4]	(4,094)		4,537
Chipeta Processing LLC [Member]
Cash flows from financing activities
Distributions to Chipeta noncontrolling interest owner		(3,370)		(3,838)
Western Gas Partners, LP [Member]
Cash flows from financing activities
Proceeds from the issuance of WES common units, net of offering expenses		(158)		0
Distributions to noncontrolling interest owners of WES		(84,172)		(63,425)
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		0		440,000
Affiliates [Member]
Cash flows from investing activities
Contributions in aid of construction costs from affiliates		1,310		2,369
Acquisitions		0		(713,596)
Affiliates [Member] | Western Gas Partners, LP [Member]
Cash flows from financing activities
Distributions to WGP unitholders	[5]	(1,730)		(606)
Third Parties [Member]
Cash flows from investing activities
Acquisitions		(155,287)		0
Proceeds from the sale of assets		$ 34		$ 138
[1]	Represents amounts earned or incurred on and subsequent to the date of the 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]	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.
[3]	See Note 5.
[4]	See Note 2.
[5]	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, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	General. Western Gas Equity Partners, LP is a Delaware master limited partnership (“MLP”) 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 MLP 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.” “MGR assets” refers to the Red Desert complex and the Granger straddle plant. WES is engaged in the business of gathering, compressing, treating, processing and transporting natural gas, and gathering, stabilizing and transporting condensate, natural gas liquids (“NGLs”) and crude oil. WES is also currently constructing two produced-water disposal systems in West Texas, which are expected to be placed in service during the second quarter of 2017. WES provides these midstream services for Anadarko, as well as for third-party producers and customers. As of March 31, 2017 , WES’s assets and investments consisted of the following: Owned and Operated Operated Interests Non-Operated Interests Equity Interests Gathering systems 12 3 3 2 Treating facilities 21 3 — 3 Natural gas processing plants/trains 20 5 — 2 NGL pipelines 2 — — 3 Natural gas pipelines 5 — — — Oil pipelines — 1 — 1 These assets and investments are located in the Rocky Mountains (Colorado, Utah and Wyoming), North-central Pennsylvania and Texas. 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) Marcellus Interest systems 33.75 % Newcastle system 50 % Springfield system 50.1 % Full consolidation Chipeta (3) 75 % DBJV system (4) 100 % (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. (4) WES acquired an additional 50% interest in the DBJV system (the “Additional DBJV System Interest”) from a third party on March 17, 2017. See Note 2 . 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. 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 2016 Form 10-K, as filed with the SEC on February 23, 2017. Management believes that the disclosures made are adequate to make the information not misleading. 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. 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. 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, which is 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 the WES RCF, 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. 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, (iv) the WES Class C units issued by WES to a subsidiary of Anadarko as part of the funding for the acquisition of Delaware Basin Midstream, LLC (“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, 2017 . 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. For those periods requiring recast, the consolidated financial statements for periods prior to the acquisition of WES assets from Anadarko are 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. Use of estimates. 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. 1. DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (CONTINUED) 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 cash payment is received from the insurance carrier or there is a binding settlement agreement with the carrier that clearly states that a 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 cash proceeds are received from insurers, which are presented in the consolidated statements of operations as a component of Operating income (loss). On December 3, 2015, there was an initial fire and secondary explosion at the processing facility within the DBM complex. The majority of the damage from the incident was to the liquid handling facilities and the amine treating units at the inlet of the complex. Train II (with capacity of 100 MMcf/d) sustained the most damage of the processing trains and returned to service in December 2016. Train III (with capacity of 200 MMcf/d) experienced minimal damage and returned to full service in May 2016. For the quarter ended March 31, 2017 , a $5.7 million loss was recorded in Gain (loss) on divestiture and other, net in the consolidated statements of operations, related to a change in WES’s estimate of the amount that will be recovered under the property insurance claim based on further discussions with insurers. As of March 31, 2017 , and December 31, 2016 , the consolidated balance sheets include receivables of zero and $30.0 million , respectively, for a property insurance claim related to the incident at the DBM complex. For the quarter ended March 31, 2017 , WES received $29.8 million in cash proceeds from insurers related to the incident at the DBM complex, including $5.8 million in proceeds from business interruption insurance claims and $24.0 million in proceeds from property insurance claims. Recently adopted accounting standards. Accounting Standards Update (“ASU”) 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business assists in determining whether a transaction should be accounted for as an acquisition or disposal of assets or as a business. This ASU provides a screen that when substantially all of the fair value of the gross assets acquired, or disposed of, are concentrated in a single identifiable asset, or a group of similar identifiable assets, the set will not be considered a business. If the screen is not met, a set must include an input and a substantive process that together significantly contribute to the ability to create an output to be considered a business. WGP’s adoption of this ASU on January 1, 2017, using a prospective approach, could have a material impact on future consolidated financial statements as goodwill will not be allocated to divestitures or recorded on acquisitions that are not considered to be a business. ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs and eliminates the exception for an intra-entity transfer of an asset other than inventory. WGP adopted this ASU on January 1, 2017, using a modified retrospective approach, with no impact to its consolidated financial statements. 1. DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (CONTINUED) New accounting standards issued but not yet adopted. ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash requires an entity to explain the changes in the total of cash, cash equivalents, restricted cash, and restricted cash equivalents on the statement of cash flows and to provide a reconciliation of the totals in that statement to the related captions in the balance sheet when the cash, cash equivalents, restricted cash, and restricted cash equivalents are presented in more than one line item on the balance sheet. This ASU is effective for annual and interim periods beginning after December 15, 2017, and is required to be adopted using a retrospective approach, with early adoption permitted. WGP is evaluating the impact of the adoption of this ASU on its consolidated financial statements. ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments provides clarification on how certain cash receipts and cash payments are presented and classified on the statement of cash flows. This ASU is effective for annual and interim periods beginning after December 15, 2017, and is required to be adopted using a retrospective approach if practicable, with early adoption permitted. WGP does not expect the adoption of this ASU to have a material impact on its consolidated statement of cash flows. ASU 2016-02, Leases (Topic 842) requires 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. The provisions of ASU 2016-02 also modify the definition of a lease and outline the requirements for recognition, measurement, presentation and disclosure of leasing arrangements by both lessees and lessors. This ASU is effective for annual and interim periods beginning after December 15, 2018. WGP is currently analyzing its portfolio of contracts to assess the impact future adoption of this ASU may have on its consolidated financial statements. ASU 2014-09, Revenue from Contracts with Customers (Topic 606) supersedes current revenue recognition requirements and requires an entity to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration the entity expects to be entitled to in exchange for those goods or services. Additional disclosures will be required to describe the nature, amount, timing and uncertainty of revenue and cash flows from contracts with customers. WGP has completed an initial review of contracts in each of its revenue streams and is developing accounting policies to address the provisions of the ASU. WGP is currently analyzing whether total revenues and total expenses may increase as a result of recognizing both revenue for noncash consideration for services provided and revenue and associated cost of product for the subsequent sale of commodities received as such noncash consideration. WGP continues to evaluate the impact of this and other provisions of the ASU on accounting policies, internal controls and consolidated financial statements and related disclosures, and has not finalized any estimates of the potential impacts. WGP will adopt the new standard on January 1, 2018, using the modified retrospective method with a cumulative adjustment to equity and partners’ capital.

Acquisitions and Divestitures

Acquisitions and Divestitures	3 Months Ended
	Mar. 31, 2017
Property, Plant and Equipment [Abstract]
Acquisitions and Divestitures	2. ACQUISITIONS AND DIVESTITURES The following table presents the acquisitions completed by WES during 2017 and 2016 , and identifies the funding sources for such acquisitions: thousands except unit and percent amounts Acquisition Date Percentage Borrowings Cash On Hand WES Common Units Issued WES Series A Preferred Units Issued Springfield system (1) 03/14/2016 50.1 % $ 247,500 $ — 2,089,602 14,030,611 DBJV system (2) 03/17/2017 50 % — 155,000 — — (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 interest.” The Springfield oil and gas gathering systems (collectively, the “Springfield system”) are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. 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 to private investors. See Note 4 for further information regarding WES’s Series A Preferred units. WGP financed the purchase of the WES common units by borrowing $25.0 million under the WGP RCF. See Note 9 . (2) WES acquired the Additional DBJV System Interest from a third party. See Property exchange below. Property exchange. On March 17, 2017, WES acquired the Additional DBJV System Interest from a third party in exchange for (a) WES’s 33.75% non-operated interest in two natural gas gathering systems located in northern Pennsylvania (the “Non-Operated Marcellus Interest”), commonly referred to as the Liberty and Rome systems, and (b) $155.0 million of cash consideration (collectively, the “Property Exchange”). WES previously held a 50% interest in, and operated, the DBJV system. The Property Exchange is reflected as a nonmonetary transaction whereby the acquired Additional DBJV System Interest is recorded at the fair value of the divested Non-Operated Marcellus Interest plus the $155.0 million of cash consideration. The Property Exchange resulted in a net gain of $125.4 million recorded as Gain (loss) on divestiture and other, net in the consolidated statements of operations. Results of operations attributable to the Property Exchange were included in the consolidated statement of operations beginning on the acquisition date in the first quarter of 2017. 2. ACQUISITIONS AND DIVESTITURES (CONTINUED) DBJV acquisition - Deferred purchase price obligation - Anadarko. The consideration to be paid by WES for the March 2015 acquisition of Delaware Basin JV Gathering LLC (“DBJV”) from Anadarko, 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. During the three months ended March 31, 2017 , WES recognized an aggregate $6.8 million decrease in the estimated future payment obligation (based on management’s estimate of WES’s share of forecasted Net Earnings and capital expenditures for DBJV), resulting in a net present value of $37.3 million for this obligation at March 31, 2017 , calculated using a discounted cash flow model with a 10% discount rate. The reduction in the value of the deferred purchase price obligation is primarily due to revisions reflecting a decrease in WES’s estimate of the average of 2018 and 2019 Net Earnings, partially offset by a decrease in WES’s estimate of aggregate capital expenditures to be incurred by DBJV through February 29, 2020. The following table summarizes the financial statement impact of the Deferred purchase price obligation - Anadarko: Deferred purchase price obligation - Anadarko Estimated future payment obligation (1) Balance at December 31, 2016 $ 41,440 $ 56,455 Accretion expense (2) 71 Revision to Deferred purchase price obligation – Anadarko (3) (4,165 ) Balance at March 31, 2017 $ 37,346 $ 49,694 (1) Calculated using Level 3 inputs. (2) Accretion expense was recorded as a charge to Interest expense on the consolidated statements of operations. (3) Recorded as revisions within Common units on the consolidated balance sheet and consolidated statement of equity and partners’ capital. Hugoton system divestiture. During the fourth quarter of 2016, the Hugoton system, located in Southwest Kansas and Oklahoma, was sold to a third party, resulting in a net loss on sale of $12.0 million recorded as Gain (loss) on divestiture and other, net in the consolidated statements of operations. WES allocated $1.6 million in goodwill to this divestiture.

Partnership Distributions

Partnership Distributions	3 Months Ended
	Mar. 31, 2017
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 (the “Board of Directors”) 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 2016 March 31 $ 0.42375 $ 92,767 May 2016 June 30 0.43375 94,958 August 2016 September 30 0.44750 97,968 November 2016 December 31 0.46250 101,254 February 2017 2017 March 31 (1) $ 0.49125 $ 107,549 May 2017 (1) The Board of Directors declared a cash distribution to WGP unitholders for the first quarter of 2017 of $0.49125 per unit, or $107.5 million in aggregate. The cash distribution is payable on May 22, 2017 , to WGP unitholders of record at the close of business on May 1, 2017 . 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 Total Quarterly Date of 2016 March 31 $ 0.815 $ 158,905 May 2016 June 30 0.830 162,827 August 2016 September 30 0.845 166,742 November 2016 December 31 0.860 170,657 February 2017 2017 March 31 (1) $ 0.875 $ 188,753 May 2017 (1) The Board of Directors of WES GP declared a cash distribution to WES unitholders for the first quarter of 2017 of $0.875 per unit, or $188.8 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 12, 2017 , to WES unitholders of record at the close of business on May 1, 2017 . WES’s available cash. The amount of available cash (as defined in WES’s partnership agreement) generally is all cash on hand at the end of the quarter, plus, at the discretion of WES GP, working capital borrowings made subsequent to the end of such quarter, less the amount of cash reserves established by WES GP to provide for the proper conduct of WES’s business, including reserves to fund future capital expenditures; to comply with applicable laws, debt instruments or other agreements; or to provide funds for distributions to WES unitholders, and to WES GP for any one or more of the next four quarters. Working capital borrowings generally include borrowings made under a credit facility or similar financing arrangement. Working capital borrowings may only be those that, at the time of such borrowings, were intended to be repaid within 12 months. In all cases, working capital borrowings are used solely for working capital purposes or to fund distributions to partners. 3. PARTNERSHIP DISTRIBUTIONS (CONTINUED) 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 March 1, 2020 (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. See Note 4 for further discussion of the WES Class C units. 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 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 following table summarizes the Series A Preferred unitholders’ cash distributions for the periods presented: thousands except per-unit amounts Quarters Ended Total Quarterly Distribution per Unit Total Quarterly Cash Distribution Date of Distribution 2016 March 31 (1) $ 0.68 $ 1,887 May 2016 June 30 (2) 0.68 14,082 August 2016 September 30 0.68 14,908 November 2016 December 31 0.68 14,908 February 2017 2017 March 31 (3) $ 0.68 $ 7,454 May 2017 (1) Quarterly per unit distribution prorated for the 18 -day period during which 14,030,611 WES Series A Preferred units were outstanding during the first quarter of 2016. (2) Full quarterly per unit distribution on 14,030,611 WES Series A Preferred units and quarterly per unit distribution prorated for the 77 -day period during which 7,892,220 WES Series A Preferred units were outstanding during the second quarter of 2016. (3) On March 1, 2017, 50% of the outstanding WES Series A Preferred units converted into WES common units on a one -for-one basis. Such converted WES common units were entitled only to distributions made to WES common unitholders with respect to the first quarter of 2017. See Note 4 . WES’s general partner interest and incentive distribution rights. As of March 31, 2017 , WES GP was entitled to 1.5% of all quarterly distributions that WES makes prior to its liquidation and, as the holder of the incentive distribution rights (“IDRs”), was entitled to incentive distributions at the maximum distribution sharing percentage of 48.0% for all periods presented, after the minimum quarterly distribution and the target distribution levels had been achieved. The maximum distribution sharing percentage of 49.5% does not include any distributions that WES GP may receive on common units that it may acquire.

Equity and Partners' Capital

Equity and Partners' Capital	3 Months Ended
	Mar. 31, 2017
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, 2017 , Anadarko held 178,587,365 of WGP’s common units, representing an 81.6% 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 40,341,205 WGP common units, representing an 18.4% limited partner interest in WGP. In June 2016, Anadarko sold 12,500,000 of its WGP common units to the public through an underwritten offering. 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. 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, 2017 , the impact of the 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, 2017 , WGP held 50,132,046 WES common units, representing a 29.9% limited partner interest in WES, and, through its ownership of WES GP, WGP indirectly held 2,583,068 general partner units, representing a 1.5% general partner interest in WES, and 100% of WES’s incentive distribution rights. As of March 31, 2017 , (i) other subsidiaries of Anadarko collectively held 2,011,380 WES common units and 12,537,100 Class C units, representing an aggregate 8.7% limited partner interest in WES, (ii) the public held 89,489,959 WES common units, representing a 53.4% limited partner interest in WES, and (iii) private investors held 10,961,416 WES Series A Preferred units, representing a 6.5% 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 ). 4. EQUITY AND PARTNERS’ CAPITAL (CONTINUED) WES Class C units. In November 2014, WES issued 10,913,853 Class C units to Anadarko Midstream Holdings (“AMH”), pursuant to a Unit Purchase Agreement with Anadarko and AMH. The Class C units were issued to partially fund WES’s acquisition of DBM. When issued, the WES Class C units were scheduled to convert into WES common units on a one -for-one basis on December 31, 2017. In February 2017, Anadarko elected to extend the conversion date of the WES Class C units to March 1, 2020. WES can elect to convert the Class C units earlier or Anadarko can extend the conversion date again. WES Series A Preferred units. In 2016, WES issued 21,922,831 WES Series A Preferred units to private investors. Pursuant to an agreement between WES and the holders of the WES Series A Preferred units, 50% of the WES Series A Preferred units converted into WES common units on a one -for-one basis on March 1, 2017, with the remaining Series A Preferred units to be converted in May 2017. WES has an effective registration statement with the SEC relating to the public resale of the WES common units issued or to be issued upon conversion of the WES Series A Preferred units. 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, 2017 : WES Common Units WES Class C Units WES Series A Preferred Units WES General Partner Units Total Balance at December 31, 2016 130,671,970 12,358,123 21,922,831 2,583,068 167,535,992 PIK Class C units — 178,977 — — 178,977 Conversion of Series A Preferred units 10,961,415 — (10,961,415 ) — — Balance at March 31, 2017 141,633,385 12,537,100 10,961,416 2,583,068 167,714,969

Transactions with Affiliates

Transactions with Affiliates	3 Months Ended
	Mar. 31, 2017
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 $311.0 million and $313.3 million at March 31, 2017 , and December 31, 2016 , 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 . 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 the London Interbank Offered Rate 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 risk inherent in its percent-of-proceeds and keep-whole contracts. 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 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. 5. TRANSACTIONS WITH AFFILIATES (CONTINUED) The following table summarizes gains and losses upon settlement of commodity price swap agreements recognized in the consolidated statements of operations: Three Months Ended thousands 2017 2016 Gains (losses) on commodity price swap agreements related to sales: (1) Natural gas sales $ 1,082 $ 7,041 Natural gas liquids sales (4,307 ) 20,070 Total (3,225 ) 27,111 Gains (losses) on commodity price swap agreements related to purchases (2) 2,696 (18,871 ) Net gains (losses) on commodity price swap agreements $ (529 ) $ 8,240 (1) Reported in affiliate Natural gas and natural gas liquids sales in the consolidated statements of operations in the period in which the related sale is recorded. (2) Reported in Cost of product in the consolidated statements of operations in the period in which the related purchase is recorded. Revenues or costs attributable to volumes settled during 2016 and 2017 for the DJ Basin complex and 2017 for the MGR assets are recognized in the consolidated statements of operations at the applicable market price in the tables below. WES also records 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 tables below. The commodity price swap agreement for the Hugoton system was in place until its divestiture in October 2016. For the three months ended March 31, 2017 , the capital contribution from Anadarko was $12.3 million . The tables below summarize the swap prices compared to the forward market prices: DJ Basin Complex per barrel except natural gas 2016 - 2017 Swap Prices 2016 Market Prices (1) 2017 Market Prices (1) Ethane $ 18.41 $ 0.60 $ 5.09 Propane 47.08 10.98 18.85 Isobutane 62.09 17.23 26.83 Normal butane 54.62 16.86 26.20 Natural gasoline 72.88 26.15 41.84 Condensate 76.47 34.65 45.40 Natural gas (per MMBtu) 5.96 2.11 3.05 (1) Represents the New York Mercantile Exchange (“NYMEX”) forward strip price as of December 8, 2015 and December 1, 2016, for the 2016 Market Prices and 2017 Market Prices, respectively, adjusted for product specification, location, basis and, in the case of NGLs, transportation and fractionation costs. 5. TRANSACTIONS WITH AFFILIATES (CONTINUED) MGR Assets per barrel except natural gas 2016 - 2017 Swap Prices 2017 Market Prices (1) Ethane $ 23.11 $ 4.08 Propane 52.90 19.24 Isobutane 73.89 25.79 Normal butane 64.93 25.16 Natural gasoline 81.68 45.01 Condensate 81.68 53.55 Natural gas (per MMBtu) 4.87 3.05 (1) Represents the NYMEX forward strip price as of December 1, 2016, adjusted for product specification, location, basis and, in the case of NGLs, transportation and fractionation costs. Gathering and processing agreements. WES has significant gathering and processing arrangements with affiliates of Anadarko on a majority of its systems. WES’s natural gas gathering, treating and transportation throughput (excluding equity investment throughput) attributable to production owned or controlled by Anadarko was 32% and 37% for the three months ended March 31, 2017 and 2016 , respectively. WES’s natural gas processing throughput (excluding equity investment throughput) attributable to production owned or controlled by Anadarko was 49% and 61% for the three months ended March 31, 2017 and 2016 , respectively. WES’s crude/NGL gathering, treating and transportation throughput (excluding equity investment throughput) attributable to production owned or controlled by Anadarko was 56% and 64% for the three months ended March 31, 2017 and 2016 , respectively. 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 (see Note 2 ). 5. TRANSACTIONS WITH AFFILIATES (CONTINUED) 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 $55,000 and $56,000 for the three months ended March 31, 2017 and 2016 , respectively. WGP LTIP and Anadarko Incentive Plan. For each of the three months ended March 31, 2017 and 2016 , general and administrative expenses included $1.2 million 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 2012 Omnibus Incentive Compensation Plan (“Anadarko Incentive Plan”). Of this amount, $1.1 million is reflected as contributions to partners’ capital in the consolidated statement of equity and partners’ capital for the three months ended March 31, 2017 . 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, 2017 and 2016 . Equipment purchases. The following table summarizes WES’s purchases from Anadarko of pipe and equipment: Three Months Ended March 31, 2017 2016 thousands Purchases Cash consideration $ — $ 1,096 Payable to affiliate — 990 Net carrying value — (1,372 ) Partners’ capital adjustment $ — $ 714 Contributions in aid of construction costs from affiliates. On certain of WES’s capital projects, Anadarko is obligated to reimburse WES for all or a portion of project capital expenditures. The majority of such arrangements are associated with projects related to pipeline construction activities and production well tie-ins. The cash receipts resulting from such reimbursements are presented as “Contributions in aid of construction costs from affiliates” within the investing section of the consolidated statements of cash flows. 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 2017 2016 Revenues and other (1) $ 315,155 $ 272,584 Equity income, net – affiliates (1) 19,461 16,814 Cost of product (1) 15,988 24,580 Operation and maintenance (2) 17,089 17,975 General and administrative (3) 9,734 9,150 Operating expenses 42,811 51,705 Interest income (4) 4,225 4,225 Interest expense (5) 71 4,537 Distributions to WGP unitholders (6) 82,597 77,152 Distributions to WES unitholders (7) 1,730 606 Above-market component of swap extensions with Anadarko 12,297 6,813 (1) Represents amounts earned or incurred on and subsequent to the date of the 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 Plan within this Note 5 ) and amounts charged by Anadarko under the WGP and WES omnibus agreements. (4) Represents interest income recognized on the note receivable from Anadarko. (5) Includes amounts related to WES’s Deferred purchase price obligation - Anadarko (see Note 2 and 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 operations.

Property, Plant and Equipment

Property, Plant and Equipment	3 Months Ended
	Mar. 31, 2017
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, 2017 December 31, 2016 Land n/a $ 4,021 $ 4,012 Gathering systems and processing complexes 3 to 47 years 6,836,748 6,462,053 Pipelines and equipment 15 to 45 years 139,376 139,646 Assets under construction n/a 230,898 226,626 Other 3 to 40 years 29,851 29,605 Total property, plant and equipment 7,240,894 6,861,942 Accumulated depreciation 1,974,081 1,812,010 Net property, plant and equipment $ 5,266,813 $ 5,049,932 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. Impairments. As of March 31, 2017 , net property, plant and equipment includes impairments of $164.7 million , including an impairment of $158.8 million at the Granger complex, which was impaired to its estimated fair value of $48.5 million using the income approach and Level 3 fair value inputs, due to a reduced throughput fee as a result of a producer’s bankruptcy. Also during the period, WES recognized additional impairments of $5.9 million , primarily related to (i) a $3.7 million impairment at the Granger straddle plant, which was impaired to its estimated salvage value of $0.6 million using the income approach and Level 3 fair value inputs and (ii) the cancellation of a pipeline project in West Texas. During 2016, WES recognized impairments of $15.5 million , including an impairment of $6.1 million at WES’s Newcastle system, which was impaired to its estimated fair value of $3.1 million using the income approach and Level 3 fair value inputs, due to a reduction in estimated future cash flows caused by the low commodity price environment. Also during 2016, WES recognized impairments of $9.4 million , primarily related to the cancellation of projects at the DJ Basin complex and Springfield and DBJV systems, and the abandonment of compressors at the MIGC system.

Equity Investments

Equity Investments	3 Months Ended
	Mar. 31, 2017
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, 2017 : Equity Investments thousands Fort White Rendezvous Mont TEG TEP FRP Total Balance at December 31, 2016 $ 12,833 $ 47,319 $ 46,739 $ 112,805 $ 15,846 $ 189,194 $ 169,472 $ 594,208 Investment earnings (loss), net of amortization 805 3,098 249 6,863 367 4,276 3,803 19,461 Distributions (845 ) (2,952 ) (734 ) (6,125 ) (272 ) (4,339 ) (3,847 ) (19,114 ) Distributions in excess of cumulative earnings (1) — (615 ) (809 ) — — (851 ) (1,178 ) (3,453 ) Balance at March 31, 2017 $ 12,793 $ 46,850 $ 45,445 $ 113,543 $ 15,941 $ 188,280 $ 168,250 $ 591,102 (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	3 Months Ended
	Mar. 31, 2017
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, 2017 December 31, 2016 Trade receivables, net $ 152,467 $ 192,606 Other receivables, net 77 30,415 Total accounts receivable, net $ 152,544 $ 223,021 A summary of other current assets is as follows: thousands March 31, 2017 December 31, 2016 Natural gas liquids inventory $ 8,348 $ 7,126 Imbalance receivables 977 3,483 Prepaid insurance 1,713 2,889 Total other current assets $ 11,038 $ 13,498 A summary of accrued liabilities is as follows: thousands March 31, 2017 December 31, 2016 Accrued interest expense $ 45,585 $ 39,834 Short-term asset retirement obligations 6,678 3,114 Short-term remediation and reclamation obligations 630 630 Income taxes payable 1,430 1,006 Other 3,760 606 Total accrued liabilities $ 58,083 $ 45,190

Debt and Interest Expense

Debt and Interest Expense	3 Months Ended
	Mar. 31, 2017
Debt Instruments [Abstract]
Debt and Interest Expense	9. DEBT AND INTEREST EXPENSE At March 31, 2017 , WGP’s debt consisted of borrowings under the WGP RCF and 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 4.650% Senior Notes due 2026 (the “2026 Notes”). The following table presents WES and WGP’s outstanding debt as of March 31, 2017 , and December 31, 2016 : March 31, 2017 December 31, 2016 thousands Principal Carrying Value Fair Value (1) Principal Carrying Value Fair Value (1) WGP RCF $ 28,000 $ 28,000 $ 28,000 $ 28,000 $ 28,000 $ 28,000 2021 Notes 500,000 494,999 537,815 500,000 494,734 536,252 2022 Notes 670,000 668,688 688,423 670,000 668,634 681,723 2018 Notes 350,000 349,311 351,970 350,000 349,188 351,531 2044 Notes 600,000 593,152 614,253 600,000 593,132 615,753 2025 Notes 500,000 491,196 494,066 500,000 490,971 492,499 2026 Notes 500,000 494,911 514,065 500,000 494,802 518,441 Total long-term debt $ 3,148,000 $ 3,120,257 $ 3,228,592 $ 3,148,000 $ 3,119,461 $ 3,224,199 (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, 2017 : thousands Carrying Value Balance at December 31, 2016 $ 3,119,461 Other 796 Balance at March 31, 2017 $ 3,120,257 WGP RCF. As of March 31, 2017 , WGP had $28.0 million outstanding borrowings and $222.0 million available for borrowing under the WGP RCF, which matures in March 2019. As of March 31, 2017 and 2016 , the interest rate on the outstanding WGP RCF borrowings was 2.99% and 2.69% , respectively. The commitment fee rate was 0.30% at March 31, 2017 and 2016 . At March 31, 2017 , WGP was in compliance with all covenants under the WGP RCF. WGP WCF. As of March 31, 2017 , WGP had no outstanding borrowings and $30.0 million available for borrowing under the WGP WCF. The interest rate on the WGP WCF, which matures in November 2017, was 2.48% and 1.94% at March 31, 2017 and 2016 , respectively. At March 31, 2017 , WGP was in compliance with all covenants under the WGP WCF. WES Senior Notes. At March 31, 2017 , WES was in compliance with all covenants under the indentures governing its outstanding notes. WES RCF. As of March 31, 2017 , WES had no outstanding WES RCF borrowings and $4.9 million in outstanding letters of credit, resulting in $1.195 billion available for borrowing under the WES RCF, which matures in February 2020. As of March 31, 2017 and 2016 , the interest rate on the outstanding WES RCF borrowings was 2.28% and 1.74% , respectively. The facility fee rate was 0.20% at March 31, 2017 and 2016 . At March 31, 2017 , WES was in compliance with all covenants under the WES RCF. 9. DEBT AND INTEREST EXPENSE (CONTINUED) Interest expense. The following table summarizes the amounts included in interest expense: Three Months Ended thousands 2017 2016 Third parties Long-term debt $ (34,814 ) $ (27,856 ) Amortization of debt issuance costs and commitment fees (1,964 ) (1,595 ) Capitalized interest 816 1,849 Total interest expense – third parties (35,962 ) (27,602 ) Affiliates Deferred purchase price obligation – Anadarko (1) (71 ) (4,537 ) Total interest expense – affiliates (71 ) (4,537 ) Interest expense $ (36,033 ) $ (32,139 ) (1) See Note 2 for a discussion of the Deferred purchase price obligation - Anadarko.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2017
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, 2017 , WES had unconditional payment obligations for services to be rendered or products to be delivered in connection with its capital projects of $36.9 million , the majority of which is expected to be paid in the next twelve months. These commitments relate primarily to (i) the construction of Train VI at the DBM complex, (ii) expansion projects at the DBJV system and the DBM and DJ Basin complexes and (iii) the construction of two produced-water disposal systems in West Texas. 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 off ices and shared field offices extend throug h 2017 a nd 2019, respectively , and the lease for the warehouse expired in February 2017. Rent expense associated with the office, warehouse and equipment leases was $7.9 million and $8.9 million for the three months ended March 31, 2017 and 2016 , respectively.

Description of Business and B19

Description of Business and Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Consolidation 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) Marcellus Interest systems 33.75 % Newcastle system 50 % Springfield system 50.1 % Full consolidation Chipeta (3) 75 % DBJV system (4) 100 % (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. (4) WES acquired an additional 50% interest in the DBJV system (the “Additional DBJV System Interest”) from a third party on March 17, 2017. See Note 2 . 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. 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 2016 Form 10-K, as filed with the SEC on February 23, 2017. Management believes that the disclosures made are adequate to make the information not misleading. 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 .
Variable interest entity policy	Variable interest entity. 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. 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, which is 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 the WES RCF, 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.
Business combinations policy	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, (iv) the WES Class C units issued by WES to a subsidiary of Anadarko as part of the funding for the acquisition of Delaware Basin Midstream, LLC (“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, 2017 . 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. For those periods requiring recast, the consolidated financial statements for periods prior to the acquisition of WES assets from Anadarko are 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.
Use of estimates policy	Use of estimates. 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.
Property, plant and equipment policy	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 cash payment is received from the insurance carrier or there is a binding settlement agreement with the carrier that clearly states that a 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 cash proceeds are received from insurers, which are presented in the consolidated statements of operations as a component of Operating income (loss). On December 3, 2015, there was an initial fire and secondary explosion at the processing facility within the DBM complex. The majority of the damage from the incident was to the liquid handling facilities and the amine treating units at the inlet of the complex. Train II (with capacity of 100 MMcf/d) sustained the most damage of the processing trains and returned to service in December 2016. Train III (with capacity of 200 MMcf/d) experienced minimal damage and returned to full service in May 2016. For the quarter ended March 31, 2017 , a $5.7 million loss was recorded in Gain (loss) on divestiture and other, net in the consolidated statements of operations, related to a change in WES’s estimate of the amount that will be recovered under the property insurance claim based on further discussions with insurers. As of March 31, 2017 , and December 31, 2016 , the consolidated balance sheets include receivables of zero and $30.0 million , respectively, for a property insurance claim related to the incident at the DBM complex. For the quarter ended March 31, 2017 , WES received $29.8 million in cash proceeds from insurers related to the incident at the DBM complex, including $5.8 million in proceeds from business interruption insurance claims and $24.0 million in proceeds from property insurance claims.
New issued accounting standards policy	Recently adopted accounting standards. Accounting Standards Update (“ASU”) 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business assists in determining whether a transaction should be accounted for as an acquisition or disposal of assets or as a business. This ASU provides a screen that when substantially all of the fair value of the gross assets acquired, or disposed of, are concentrated in a single identifiable asset, or a group of similar identifiable assets, the set will not be considered a business. If the screen is not met, a set must include an input and a substantive process that together significantly contribute to the ability to create an output to be considered a business. WGP’s adoption of this ASU on January 1, 2017, using a prospective approach, could have a material impact on future consolidated financial statements as goodwill will not be allocated to divestitures or recorded on acquisitions that are not considered to be a business. ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs and eliminates the exception for an intra-entity transfer of an asset other than inventory. WGP adopted this ASU on January 1, 2017, using a modified retrospective approach, with no impact to its consolidated financial statements. 1. DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (CONTINUED) New accounting standards issued but not yet adopted. ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash requires an entity to explain the changes in the total of cash, cash equivalents, restricted cash, and restricted cash equivalents on the statement of cash flows and to provide a reconciliation of the totals in that statement to the related captions in the balance sheet when the cash, cash equivalents, restricted cash, and restricted cash equivalents are presented in more than one line item on the balance sheet. This ASU is effective for annual and interim periods beginning after December 15, 2017, and is required to be adopted using a retrospective approach, with early adoption permitted. WGP is evaluating the impact of the adoption of this ASU on its consolidated financial statements. ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments provides clarification on how certain cash receipts and cash payments are presented and classified on the statement of cash flows. This ASU is effective for annual and interim periods beginning after December 15, 2017, and is required to be adopted using a retrospective approach if practicable, with early adoption permitted. WGP does not expect the adoption of this ASU to have a material impact on its consolidated statement of cash flows. ASU 2016-02, Leases (Topic 842) requires 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. The provisions of ASU 2016-02 also modify the definition of a lease and outline the requirements for recognition, measurement, presentation and disclosure of leasing arrangements by both lessees and lessors. This ASU is effective for annual and interim periods beginning after December 15, 2018. WGP is currently analyzing its portfolio of contracts to assess the impact future adoption of this ASU may have on its consolidated financial statements. ASU 2014-09, Revenue from Contracts with Customers (Topic 606) supersedes current revenue recognition requirements and requires an entity to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration the entity expects to be entitled to in exchange for those goods or services. Additional disclosures will be required to describe the nature, amount, timing and uncertainty of revenue and cash flows from contracts with customers. WGP has completed an initial review of contracts in each of its revenue streams and is developing accounting policies to address the provisions of the ASU. WGP is currently analyzing whether total revenues and total expenses may increase as a result of recognizing both revenue for noncash consideration for services provided and revenue and associated cost of product for the subsequent sale of commodities received as such noncash consideration. WGP continues to evaluate the impact of this and other provisions of the ASU on accounting policies, internal controls and consolidated financial statements and related disclosures, and has not finalized any estimates of the potential impacts. WGP will adopt the new standard on January 1, 2018, using the modified retrospective method with a cumulative adjustment to equity and partners’ capital.
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, 2017 , the impact of the 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.

Description of Business and B20

Description of Business and Basis of Presentation (Tables)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Assets and Investments Table	As of March 31, 2017 , WES’s assets and investments consisted of the following: Owned and Operated Operated Interests Non-Operated Interests Equity Interests Gathering systems 12 3 3 2 Treating facilities 21 3 — 3 Natural gas processing plants/trains 20 5 — 2 NGL pipelines 2 — — 3 Natural gas pipelines 5 — — — Oil pipelines — 1 — 1
Ownership Interest and Method of Consolidation Table	The following table outlines 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) Marcellus Interest systems 33.75 % Newcastle system 50 % Springfield system 50.1 % Full consolidation Chipeta (3) 75 % DBJV system (4) 100 % (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. (4) WES acquired an additional 50% interest in the DBJV system (the “Additional DBJV System Interest”) from a third party on March 17, 2017. See Note 2 .

Acquisitions and Divestitures (

Acquisitions and Divestitures (Tables)	3 Months Ended
	Mar. 31, 2017
Property, Plant and Equipment [Abstract]
Acquisitions Table	The following table presents the acquisitions completed by WES during 2017 and 2016 , and identifies the funding sources for such acquisitions: thousands except unit and percent amounts Acquisition Date Percentage Borrowings Cash On Hand WES Common Units Issued WES Series A Preferred Units Issued Springfield system (1) 03/14/2016 50.1 % $ 247,500 $ — 2,089,602 14,030,611 DBJV system (2) 03/17/2017 50 % — 155,000 — — (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 interest.” The Springfield oil and gas gathering systems (collectively, the “Springfield system”) are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. 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 to private investors. See Note 4 for further information regarding WES’s Series A Preferred units. WGP financed the purchase of the WES common units by borrowing $25.0 million under the WGP RCF. See Note 9 . (2) WES acquired the Additional DBJV System Interest from a third party. See Property exchange below.
Impact of Deferred Purchase Price Obligation Table	The following table summarizes the financial statement impact of the Deferred purchase price obligation - Anadarko: Deferred purchase price obligation - Anadarko Estimated future payment obligation (1) Balance at December 31, 2016 $ 41,440 $ 56,455 Accretion expense (2) 71 Revision to Deferred purchase price obligation – Anadarko (3) (4,165 ) Balance at March 31, 2017 $ 37,346 $ 49,694 (1) Calculated using Level 3 inputs. (2) Accretion expense was recorded as a charge to Interest expense on the consolidated statements of operations. (3) Recorded as revisions within Common units on the consolidated balance sheet and consolidated statement of equity and partners’ capital.

Partnership Distributions (Tabl

Partnership Distributions (Tables)	3 Months Ended
	Mar. 31, 2017
Distribution Made to Limited Partner [Line Items]
Cash Distributions Tables	The Board of Directors of WGP GP (the “Board of Directors”) 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 2016 March 31 $ 0.42375 $ 92,767 May 2016 June 30 0.43375 94,958 August 2016 September 30 0.44750 97,968 November 2016 December 31 0.46250 101,254 February 2017 2017 March 31 (1) $ 0.49125 $ 107,549 May 2017 (1) The Board of Directors declared a cash distribution to WGP unitholders for the first quarter of 2017 of $0.49125 per unit, or $107.5 million in aggregate. The cash distribution is payable on May 22, 2017 , to WGP unitholders of record at the close of business on May 1, 2017 .
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 Total Quarterly Date of 2016 March 31 $ 0.815 $ 158,905 May 2016 June 30 0.830 162,827 August 2016 September 30 0.845 166,742 November 2016 December 31 0.860 170,657 February 2017 2017 March 31 (1) $ 0.875 $ 188,753 May 2017 (1) The Board of Directors of WES GP declared a cash distribution to WES unitholders for the first quarter of 2017 of $0.875 per unit, or $188.8 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 12, 2017 , to WES unitholders of record at the close of business on May 1, 2017 .
Western Gas Partners, LP [Member] | Series A Preferred Units [Member]
Distribution Made to Limited Partner [Line Items]
Cash Distributions Tables	The following table summarizes the Series A Preferred unitholders’ cash distributions for the periods presented: thousands except per-unit amounts Quarters Ended Total Quarterly Distribution per Unit Total Quarterly Cash Distribution Date of Distribution 2016 March 31 (1) $ 0.68 $ 1,887 May 2016 June 30 (2) 0.68 14,082 August 2016 September 30 0.68 14,908 November 2016 December 31 0.68 14,908 February 2017 2017 March 31 (3) $ 0.68 $ 7,454 May 2017 (1) Quarterly per unit distribution prorated for the 18 -day period during which 14,030,611 WES Series A Preferred units were outstanding during the first quarter of 2016. (2) Full quarterly per unit distribution on 14,030,611 WES Series A Preferred units and quarterly per unit distribution prorated for the 77 -day period during which 7,892,220 WES Series A Preferred units were outstanding during the second quarter of 2016. (3) On March 1, 2017, 50% of the outstanding WES Series A Preferred units converted into WES common units on a one -for-one basis. Such converted WES common units were entitled only to distributions made to WES common unitholders with respect to the first quarter of 2017. See Note 4 .

Equity and Partners' Capital (T

Equity and Partners' Capital (Tables)	3 Months Ended
	Mar. 31, 2017
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, 2017 : WES Common Units WES Class C Units WES Series A Preferred Units WES General Partner Units Total Balance at December 31, 2016 130,671,970 12,358,123 21,922,831 2,583,068 167,535,992 PIK Class C units — 178,977 — — 178,977 Conversion of Series A Preferred units 10,961,415 — (10,961,415 ) — — Balance at March 31, 2017 141,633,385 12,537,100 10,961,416 2,583,068 167,714,969

Transactions with Affiliates (T

Transactions with Affiliates (Tables)	3 Months Ended
	Mar. 31, 2017
Related Party Fees and Other Arrangements, Limited Liability Company (LLC) or Limited Partnership (LP) [Abstract]
Gains (Losses) on Commodity Price Swap Agreements Table	The following table summarizes gains and losses upon settlement of commodity price swap agreements recognized in the consolidated statements of operations: Three Months Ended thousands 2017 2016 Gains (losses) on commodity price swap agreements related to sales: (1) Natural gas sales $ 1,082 $ 7,041 Natural gas liquids sales (4,307 ) 20,070 Total (3,225 ) 27,111 Gains (losses) on commodity price swap agreements related to purchases (2) 2,696 (18,871 ) Net gains (losses) on commodity price swap agreements $ (529 ) $ 8,240 (1) Reported in affiliate Natural gas and natural gas liquids sales in the consolidated statements of operations in the period in which the related sale is recorded. (2) Reported in Cost of product in the consolidated statements of operations in the period in which the related purchase is recorded.
Commodity Price Swap Agreements Extensions Tables	The tables below summarize the swap prices compared to the forward market prices: DJ Basin Complex per barrel except natural gas 2016 - 2017 Swap Prices 2016 Market Prices (1) 2017 Market Prices (1) Ethane $ 18.41 $ 0.60 $ 5.09 Propane 47.08 10.98 18.85 Isobutane 62.09 17.23 26.83 Normal butane 54.62 16.86 26.20 Natural gasoline 72.88 26.15 41.84 Condensate 76.47 34.65 45.40 Natural gas (per MMBtu) 5.96 2.11 3.05 (1) Represents the New York Mercantile Exchange (“NYMEX”) forward strip price as of December 8, 2015 and December 1, 2016, for the 2016 Market Prices and 2017 Market Prices, respectively, adjusted for product specification, location, basis and, in the case of NGLs, transportation and fractionation costs. 5. TRANSACTIONS WITH AFFILIATES (CONTINUED) MGR Assets per barrel except natural gas 2016 - 2017 Swap Prices 2017 Market Prices (1) Ethane $ 23.11 $ 4.08 Propane 52.90 19.24 Isobutane 73.89 25.79 Normal butane 64.93 25.16 Natural gasoline 81.68 45.01 Condensate 81.68 53.55 Natural gas (per MMBtu) 4.87 3.05 (1) Represents the NYMEX forward strip price as of December 1, 2016, 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, 2017 2016 thousands Purchases Cash consideration $ — $ 1,096 Payable to affiliate — 990 Net carrying value — (1,372 ) Partners’ capital adjustment $ — $ 714 The following table summarizes material affiliate transactions. See Note 2 for discussion of affiliate acquisitions and related funding. Three Months Ended thousands 2017 2016 Revenues and other (1) $ 315,155 $ 272,584 Equity income, net – affiliates (1) 19,461 16,814 Cost of product (1) 15,988 24,580 Operation and maintenance (2) 17,089 17,975 General and administrative (3) 9,734 9,150 Operating expenses 42,811 51,705 Interest income (4) 4,225 4,225 Interest expense (5) 71 4,537 Distributions to WGP unitholders (6) 82,597 77,152 Distributions to WES unitholders (7) 1,730 606 Above-market component of swap extensions with Anadarko 12,297 6,813 (1) Represents amounts earned or incurred on and subsequent to the date of the 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 Plan within this Note 5 ) and amounts charged by Anadarko under the WGP and WES omnibus agreements. (4) Represents interest income recognized on the note receivable from Anadarko. (5) Includes amounts related to WES’s Deferred purchase price obligation - Anadarko (see Note 2 and 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, 2017
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, 2017 December 31, 2016 Land n/a $ 4,021 $ 4,012 Gathering systems and processing complexes 3 to 47 years 6,836,748 6,462,053 Pipelines and equipment 15 to 45 years 139,376 139,646 Assets under construction n/a 230,898 226,626 Other 3 to 40 years 29,851 29,605 Total property, plant and equipment 7,240,894 6,861,942 Accumulated depreciation 1,974,081 1,812,010 Net property, plant and equipment $ 5,266,813 $ 5,049,932

Equity Investments (Tables)

Equity Investments (Tables)	3 Months Ended
	Mar. 31, 2017
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, 2017 : Equity Investments thousands Fort White Rendezvous Mont TEG TEP FRP Total Balance at December 31, 2016 $ 12,833 $ 47,319 $ 46,739 $ 112,805 $ 15,846 $ 189,194 $ 169,472 $ 594,208 Investment earnings (loss), net of amortization 805 3,098 249 6,863 367 4,276 3,803 19,461 Distributions (845 ) (2,952 ) (734 ) (6,125 ) (272 ) (4,339 ) (3,847 ) (19,114 ) Distributions in excess of cumulative earnings (1) — (615 ) (809 ) — — (851 ) (1,178 ) (3,453 ) Balance at March 31, 2017 $ 12,793 $ 46,850 $ 45,445 $ 113,543 $ 15,941 $ 188,280 $ 168,250 $ 591,102 (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, 2017
Components Of Working Capital [Abstract]
Accounts Receivable, Net Table	A summary of accounts receivable, net is as follows: thousands March 31, 2017 December 31, 2016 Trade receivables, net $ 152,467 $ 192,606 Other receivables, net 77 30,415 Total accounts receivable, net $ 152,544 $ 223,021
Other Current Assets Table	A summary of other current assets is as follows: thousands March 31, 2017 December 31, 2016 Natural gas liquids inventory $ 8,348 $ 7,126 Imbalance receivables 977 3,483 Prepaid insurance 1,713 2,889 Total other current assets $ 11,038 $ 13,498
Accrued Liabilities Table	A summary of accrued liabilities is as follows: thousands March 31, 2017 December 31, 2016 Accrued interest expense $ 45,585 $ 39,834 Short-term asset retirement obligations 6,678 3,114 Short-term remediation and reclamation obligations 630 630 Income taxes payable 1,430 1,006 Other 3,760 606 Total accrued liabilities $ 58,083 $ 45,190

Debt and Interest Expense (Tabl

Debt and Interest Expense (Tables)	3 Months Ended
	Mar. 31, 2017
Debt Instruments [Abstract]
Debt Outstanding and Debt Activity Tables	The following table presents WES and WGP’s outstanding debt as of March 31, 2017 , and December 31, 2016 : March 31, 2017 December 31, 2016 thousands Principal Carrying Value Fair Value (1) Principal Carrying Value Fair Value (1) WGP RCF $ 28,000 $ 28,000 $ 28,000 $ 28,000 $ 28,000 $ 28,000 2021 Notes 500,000 494,999 537,815 500,000 494,734 536,252 2022 Notes 670,000 668,688 688,423 670,000 668,634 681,723 2018 Notes 350,000 349,311 351,970 350,000 349,188 351,531 2044 Notes 600,000 593,152 614,253 600,000 593,132 615,753 2025 Notes 500,000 491,196 494,066 500,000 490,971 492,499 2026 Notes 500,000 494,911 514,065 500,000 494,802 518,441 Total long-term debt $ 3,148,000 $ 3,120,257 $ 3,228,592 $ 3,148,000 $ 3,119,461 $ 3,224,199 (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, 2017 : thousands Carrying Value Balance at December 31, 2016 $ 3,119,461 Other 796 Balance at March 31, 2017 $ 3,120,257
Interest Expense Table	The following table summarizes the amounts included in interest expense: Three Months Ended thousands 2017 2016 Third parties Long-term debt $ (34,814 ) $ (27,856 ) Amortization of debt issuance costs and commitment fees (1,964 ) (1,595 ) Capitalized interest 816 1,849 Total interest expense – third parties (35,962 ) (27,602 ) Affiliates Deferred purchase price obligation – Anadarko (1) (71 ) (4,537 ) Total interest expense – affiliates (71 ) (4,537 ) Interest expense $ (36,033 ) $ (32,139 ) (1) See Note 2 for a discussion of the Deferred purchase price obligation - Anadarko.

Description of Business and B29

Description of Business and Basis of Presentation - Assets and Investments Table (Details) - Western Gas Partners, LP [Member]	Mar. 31, 2017unit
Owned and Operated [Member] | Gathering Systems [Member]
Assets [Line Items]
Assets, number of units	12
Owned and Operated [Member] | Treating Facilities [Member]
Assets [Line Items]
Assets, number of units	21
Owned and Operated [Member] | Natural Gas Processing Plants/Trains [Member]
Assets [Line Items]
Assets, number of units	20
Owned and Operated [Member] | Natural Gas Liquids Pipelines [Member]
Assets [Line Items]
Assets, number of units	2
Owned and Operated [Member] | Natural Gas Pipelines [Member]
Assets [Line Items]
Assets, number of units	5
Operated Interests [Member] | Gathering Systems [Member]
Assets [Line Items]
Assets, number of units	3
Operated Interests [Member] | Treating Facilities [Member]
Assets [Line Items]
Assets, number of units	3
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	3
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)		Mar. 17, 2017	Mar. 31, 2017
Chipeta Processing LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership interest by noncontrolling interest owner			25.00%
Western Gas Partners, LP [Member] | Delaware Basin JV Gathering LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership percentage acquired	[1]	50.00%
Western Gas Partners, LP [Member] | Equity Investments [Member] | Fort Union [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[2]		14.81%
Western Gas Partners, LP [Member] | Equity Investments [Member] | White Cliffs [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[2]		10.00%
Western Gas Partners, LP [Member] | Equity Investments [Member] | Rendezvous [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[2]		22.00%
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	[2]		25.00%
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	[2]		20.00%
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	[2]		20.00%
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	[2]		33.33%
Western Gas Partners, LP [Member] | Proportionate Consolidation [Member] | Marcellus Interest [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[3]		33.75%
Western Gas Partners, LP [Member] | Proportionate Consolidation [Member] | Newcastle [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[3]		50.00%
Western Gas Partners, LP [Member] | Proportionate Consolidation [Member] | Springfield [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[3]		50.10%
Western Gas Partners, LP [Member] | Full Consolidation [Member] | Chipeta Processing LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[4]		75.00%
Western Gas Partners, LP [Member] | Full Consolidation [Member] | Delaware Basin JV Gathering LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[5]		100.00%
[1]	WES acquired the Additional DBJV System Interest from a third party. See Property exchange below.
[2]	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.
[3]	WGP proportionately consolidates WES’s associated share of the assets, liabilities, revenues and expenses attributable to these assets.
[4]	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.
[5]	WES acquired an additional 50% interest in the DBJV system (the “Additional DBJV System Interest”) from a third party on March 17, 2017. See Note 2.

Description of Business and B31

Description of Business and Basis of Presentation - Additional Information (Details)	3 Months Ended
	Mar. 31, 2017USD ($)Mcf / dshares	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)	May 31, 2008USD ($)
Note receivable - Anadarko	$ 260,000,000		$ 260,000,000
Loss on divestiture and other, net	(119,487,000)	$ 632,000
Proceeds from property insurance claims	$ 24,000,000	$ 0
Chipeta Processing LLC [Member]
Ownership interest by noncontrolling interest owner	25.00%
Western Gas Partners, LP [Member] | Delaware Basin Midstream Complex [Member]
Loss on divestiture and other, net	$ 5,700,000
Property insurance claim receivable	0		$ 30,000,000
Proceeds from insurance claims, total	29,800,000
Proceeds from business interruption insurance claims	5,767,000
Proceeds from property insurance claims	$ 24,000,000
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]
WES common units issued | shares	2,011,380
Western Gas Partners, LP [Member] | Affiliates [Member]
Note receivable - Anadarko	$ 260,000,000			$ 260,000,000
Western Gas Partners, LP [Member] | General Partner [Member]
Percentage ownership interest	100.00%

Acquisitions and Divestitures -

Acquisitions and Divestitures - Acquisitions Table (Details) - USD ($) $ in Thousands		Mar. 17, 2017	Mar. 14, 2016	Mar. 31, 2017
Revolving Credit Facility [Member] | WGP RCF [Member]
Business Acquisition [Line Items]
Borrowings - revolving credit facility			$ 25,000
Western Gas Partners, LP [Member]
Business Acquisition [Line Items]
WES units issued				178,977
Western Gas Partners, LP [Member] | Springfield [Member]
Business Acquisition [Line Items]
Ownership percentage acquired	[1]		50.10%
Acquisition price			$ 750,000
Cash payment for acquisition			712,500
Western Gas Partners, LP [Member] | Springfield [Member] | Revolving Credit Facility [Member] | WES RCF [Member]
Business Acquisition [Line Items]
Borrowings - revolving credit facility	[1]		$ 247,500
Western Gas Partners, LP [Member] | Springfield [Member] | Common Units [Member]
Business Acquisition [Line Items]
WES units issued	[1]		2,089,602
Western Gas Partners, LP [Member] | Springfield [Member] | Common Units [Member] | Anadarko [Member]
Business Acquisition [Line Items]
WES units issued			1,253,761
Western Gas Partners, LP [Member] | Springfield [Member] | Common Units [Member] | Western Gas Equity Partners, LP [Member]
Business Acquisition [Line Items]
WES units issued			835,841
Western Gas Partners, LP [Member] | Springfield [Member] | Series A Preferred Units [Member]
Business Acquisition [Line Items]
WES units issued	[1]		14,030,611
Western Gas Partners, LP [Member] | Delaware Basin JV Gathering LLC [Member]
Business Acquisition [Line Items]
Ownership percentage acquired	[2]	50.00%
Cash on hand	[2]	$ 155,000
[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 interest.” The Springfield oil and gas gathering systems (collectively, the “Springfield system”) are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. 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 to private investors. See Note 4 for further information regarding WES’s Series A Preferred units. WGP financed the purchase of the WES common units by borrowing $25.0 million under the WGP RCF. See Note 9.
[2]	WES acquired the Additional DBJV System Interest from a third party. See Property exchange below.

Acquisitions and Divestitures33

Acquisitions and Divestitures - Impact of the Deferred Purchase Price Obligation - Anadarko Table (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Deferred purchase price obligation - Anadarko, present value	[1]	$ 37,346		$ 41,440
Deferred Purchase Price Obligation - Anadarko [Member] | Affiliates [Member]
Property, Plant and Equipment [Line Items]
Accretion expense	[2]	71	$ 4,537
Western Gas Partners, LP [Member] | Deferred Purchase Price Obligation - Anadarko [Member] | Delaware Basin JV Gathering LLC [Member] | Affiliates [Member]
Property, Plant and Equipment [Line Items]
Deferred purchase price obligation - Anadarko, present value		37,346		41,440
Accretion expense	[3]	71
Revision to Deferred purchase price obligation – Anadarko	[4]	(4,165)
Deferred purchase price obligation - Anadarko, future value	[5]	$ 49,694		$ 56,455
[1]	See Note 2.
[2]	See Note 2 for a discussion of the Deferred purchase price obligation - Anadarko.
[3]	Accretion expense was recorded as a charge to Interest expense on the consolidated statements of operations.
[4]	Recorded as revisions within Common units on the consolidated balance sheet and consolidated statement of equity and partners’ capital.
[5]	Calculated using Level 3 inputs.

Acquisitions and Divestitures34

Acquisitions and Divestitures - Additional Information (Details) - USD ($) $ in Thousands		Mar. 17, 2017	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Deferred purchase price obligation - Anadarko, present value	[1]		$ 37,346		$ 41,440
Affiliates [Member]
Property, Plant and Equipment [Line Items]
Cash payment			0	$ 713,596
Western Gas Partners, LP [Member] | Hugoton System [Member]
Property, Plant and Equipment [Line Items]
Loss on sale of assets					12,000
Goodwill allocated to divestiture					1,600
Western Gas Partners, LP [Member] | Delaware Basin JV Gathering LLC [Member]
Property, Plant and Equipment [Line Items]
Percentage ownership interest		50.00%
Cash payment	[2]	$ 155,000
Net gain from property exchange			125,400
Western Gas Partners, LP [Member] | Delaware Basin JV Gathering LLC [Member] | Deferred Purchase Price Obligation - Anadarko [Member] | Affiliates [Member]
Property, Plant and Equipment [Line Items]
Deferred purchase price obligation - Anadarko, future value change			6,800
Deferred purchase price obligation - Anadarko, present value			$ 37,346		$ 41,440
Discount rate percentage			10.00%
Western Gas Partners, LP [Member] | Non-Operated Marcellus Interest [Member]
Property, Plant and Equipment [Line Items]
Percentage ownership interest		33.75%
[1]	See Note 2.
[2]	WES acquired the Additional DBJV System Interest from a third party. See Property exchange below.

Partnership Distributions - Cas

Partnership Distributions - Cash Distributions Tables (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016
Distribution Made to Limited Partner [Line Items]
Total quarterly distribution per unit	$ 0.49125	[1]	$ 0.46250	$ 0.44750	$ 0.43375	$ 0.42375
Total quarterly cash distribution	$ 107,549	[1]	$ 101,254	$ 97,968	$ 94,958	$ 92,767
Western Gas Partners, LP [Member]
Distribution Made to Limited Partner [Line Items]
Total quarterly distribution per unit	$ 0.875	[2]	$ 0.860	$ 0.845	$ 0.830	$ 0.815
Total quarterly cash distribution	$ 188,753	[2]	$ 170,657	$ 166,742	$ 162,827	$ 158,905
[1]	The Board of Directors declared a cash distribution to WGP unitholders for the first quarter of 2017 of $0.49125 per unit, or $107.5 million in aggregate. The cash distribution is payable on May 22, 2017, to WGP unitholders of record at the close of business on May 1, 2017.
[2]	The Board of Directors of WES GP declared a cash distribution to WES unitholders for the first quarter of 2017 of $0.875 per unit, or $188.8 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 12, 2017, to WES unitholders of record at the close of business on May 1, 2017.

Partnership Distributions - Ser

Partnership Distributions - Series A Preferred Unit Distributions Table (Details) - Western Gas Partners, LP [Member] - USD ($) $ / shares in Units, $ in Thousands	Mar. 01, 2017	Mar. 31, 2017		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2016
Distribution Made to Limited Partner [Line Items]
Units issued		178,977
Series A Preferred Units [Member]
Distribution Made to Limited Partner [Line Items]
Series A Preferred units quarterly distribution per unit		$ 0.68	[1]	$ 0.68	$ 0.68	$ 0.68	[2]	$ 0.68	[3]
Series A Preferred units quarterly cash distribution		$ 7,454	[1]	$ 14,908	$ 14,908	$ 14,082	[2]	$ 1,887	[3]
Number of days in prorated period						77 days		18 days
Series A Preferred Units [Member] | Series A Preferred Units March 2017 Conversion [Member]
Distribution Made to Limited Partner [Line Items]
Series A Preferred units, percentage converted	50.00%
Series A Preferred units, units issued upon conversion	1
Series A Preferred Units [Member] | Private Investor [Member]
Distribution Made to Limited Partner [Line Items]
Units issued								14,030,611		21,922,831
Series A Preferred Units [Member] | Private Investor [Member] | Over-Allotment Option [Member]
Distribution Made to Limited Partner [Line Items]
Units issued						7,892,220
[1]	On March 1, 2017, 50% of the outstanding WES Series A Preferred units converted into WES common units on a one-for-one basis. Such converted WES common units were entitled only to distributions made to WES common unitholders with respect to the first quarter of 2017. See Note 4.
[2]	Full quarterly per unit distribution on 14,030,611 WES Series A Preferred units and quarterly per unit distribution prorated for the 77-day period during which 7,892,220 WES Series A Preferred units were outstanding during the second quarter of 2016.
[3]	Quarterly per unit distribution prorated for the 18-day period during which 14,030,611 WES Series A Preferred units were outstanding during the first quarter of 2016.

Partnership Distributions - Add

Partnership Distributions - Additional Information (Details) - $ / shares	3 Months Ended
	Mar. 31, 2017		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	[2]	Mar. 31, 2016	[3]
Distribution Made to Limited Partner [Line Items]
Partnership agreement day requirement of distribution of available cash	55 days
Western Gas Partners, LP [Member]
Distribution Made to Limited Partner [Line Items]
Partnership agreement day requirement of distribution of available cash	45 days
Incentive distributions percentage	48.00%
Western Gas Partners, LP [Member] | Minimum [Member]
Distribution Made to Limited Partner [Line Items]
Distribution sharing percentage	1.50%
Western Gas Partners, LP [Member] | Maximum [Member]
Distribution Made to Limited Partner [Line Items]
Distribution sharing percentage	49.50%
Western Gas Partners, LP [Member] | Class C Units [Member]
Distribution Made to Limited Partner [Line Items]
Discount rate percentage	6.00%
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	[1]	$ 0.68	$ 0.68	$ 0.68		$ 0.68
[1]	On March 1, 2017, 50% of the outstanding WES Series A Preferred units converted into WES common units on a one-for-one basis. Such converted WES common units were entitled only to distributions made to WES common unitholders with respect to the first quarter of 2017. See Note 4.
[2]	Full quarterly per unit distribution on 14,030,611 WES Series A Preferred units and quarterly per unit distribution prorated for the 77-day period during which 7,892,220 WES Series A Preferred units were outstanding during the second quarter of 2016.
[3]	Quarterly per unit distribution prorated for the 18-day period during which 14,030,611 WES Series A Preferred units were outstanding during the first quarter of 2016.

Equity and Partners' Capital -

Equity and Partners' Capital - Partnership Interests Table (Details) - Western Gas Partners, LP [Member]	3 Months Ended
	Mar. 31, 2017shares
Capital Unit [Line Items]
Balance	167,535,992
Units issued	178,977
Conversion of Series A Preferred units	0
Balance	167,714,969
Common Units [Member]
Capital Unit [Line Items]
Balance	130,671,970
Conversion of Series A Preferred units	10,961,415
Balance	141,633,385
Class C Units [Member]
Capital Unit [Line Items]
Balance	12,358,123
Units issued	178,977
Balance	12,537,100
Series A Preferred Units [Member]
Capital Unit [Line Items]
Balance	21,922,831
Conversion of Series A Preferred units	(10,961,415)
Balance	10,961,416
General Partner [Member]
Capital Unit [Line Items]
Balance	2,583,068
Balance	2,583,068

Equity and Partners' Capital 39

Equity and Partners' Capital - Additional Information (Details)	Mar. 01, 2017shares	Jun. 30, 2016shares	Jun. 30, 2015$ / unitshares	Nov. 30, 2014shares	Mar. 31, 2017shares	Jun. 30, 2016shares	Mar. 31, 2016shares	Dec. 31, 2016shares
Schedule of Investments [Line Items]
Limited partner units owned					218,928,570			218,928,570
Anadarko [Member]
Schedule of Investments [Line Items]
Limited partner units owned					178,587,365
Ownership interest					81.60%
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] | Over-Allotment Option [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		12,500,000
Public [Member]
Schedule of Investments [Line Items]
Limited partner units owned					40,341,205
Ownership interest					18.40%
Western Gas Partners, LP [Member]
Schedule of Investments [Line Items]
General partner units owned					2,583,068
General partner's interest					1.50%
Units issued					178,977
Western Gas Partners, LP [Member] | Common Units [Member]
Schedule of Investments [Line Items]
Limited partner units owned					50,132,046
Ownership interest					29.90%
Western Gas Partners, LP [Member] | Incentive Distribution Rights [Member]
Schedule of Investments [Line Items]
General partner's interest					100.00%
Western Gas Partners, LP [Member] | Class C Units [Member]
Schedule of Investments [Line Items]
Units issued					178,977
Class C units, units issued upon conversion					1
Western Gas Partners, LP [Member] | Series A Preferred Units [Member] | Series A Preferred Units March 2017 Conversion [Member]
Schedule of Investments [Line Items]
Series A Preferred units, percentage converted	50.00%
Series A Preferred units, units issued upon conversion	1
Western Gas Partners, LP [Member] | Series A Preferred Units [Member] | Series A Preferred Units May 2017 Conversion [Member]
Schedule of Investments [Line Items]
Series A Preferred units, percentage converted					50.00%
Western Gas Partners, LP [Member] | Series A Preferred Units [Member] | Private Investor [Member]
Schedule of Investments [Line Items]
Limited partner units owned					10,961,416
Ownership interest					6.50%
Units issued							14,030,611	21,922,831
Western Gas Partners, LP [Member] | Series A Preferred Units [Member] | Private Investor [Member] | Over-Allotment Option [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					89,489,959
Ownership interest					53.40%
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] | Class C Units [Member]
Schedule of Investments [Line Items]
Limited partner units owned					12,537,100
Units issued				10,913,853
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%

Transactions with Affiliates -

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, 2017	Mar. 31, 2016
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements		$ (529)	$ 8,240
Sales [Member]
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements	[1]	(3,225)	27,111
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]	1,082	7,041
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]	(4,307)	20,070
Purchases [Member]
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements	[2]	$ 2,696	$ (18,871)
[1]	Reported in affiliate Natural gas and natural gas liquids sales in the consolidated statements of operations in the period in which the related sale is recorded.
[2]	Reported in Cost of product in the consolidated statements of operations in the period in which the related purchase is recorded.

Transactions with Affiliates 41

Transactions with Affiliates - Commodity Price Swap Agreements Extensions Tables (Details) - Western Gas Partners, LP [Member]		Mar. 31, 2017$ / MMBTU$ / bbl	Dec. 01, 2016$ / MMBTU$ / bbl	Dec. 08, 2015$ / MMBTU$ / bbl
DJ Basin Complex [Member] | Years 2016 - 2017 [Member] | Ethane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		18.41
DJ Basin Complex [Member] | Years 2016 - 2017 [Member] | Propane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		47.08
DJ Basin Complex [Member] | Years 2016 - 2017 [Member] | Isobutane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		62.09
DJ Basin Complex [Member] | Years 2016 - 2017 [Member] | Normal butane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		54.62
DJ Basin Complex [Member] | Years 2016 - 2017 [Member] | Natural gasoline [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		72.88
DJ Basin Complex [Member] | Years 2016 - 2017 [Member] | Condensate [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		76.47
DJ Basin Complex [Member] | Years 2016 - 2017 [Member] | Natural gas (per MMBtu) [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price | $ / MMBTU		5.96
DJ Basin Complex [Member] | Year 2016 [Member] | Ethane [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price	[1]			0.60
DJ Basin Complex [Member] | Year 2016 [Member] | Propane [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price	[1]			10.98
DJ Basin Complex [Member] | Year 2016 [Member] | Isobutane [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price	[1]			17.23
DJ Basin Complex [Member] | Year 2016 [Member] | Normal butane [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price	[1]			16.86
DJ Basin Complex [Member] | Year 2016 [Member] | Natural gasoline [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price	[1]			26.15
DJ Basin Complex [Member] | Year 2016 [Member] | Condensate [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price	[1]			34.65
DJ Basin Complex [Member] | Year 2016 [Member] | Natural gas (per MMBtu) [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price | $ / MMBTU	[1]			2.11
DJ Basin Complex [Member] | Year 2017 [Member] | Ethane [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price	[1]		5.09
DJ Basin Complex [Member] | Year 2017 [Member] | Propane [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price	[1]		18.85
DJ Basin Complex [Member] | Year 2017 [Member] | Isobutane [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price	[1]		26.83
DJ Basin Complex [Member] | Year 2017 [Member] | Normal butane [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price	[1]		26.20
DJ Basin Complex [Member] | Year 2017 [Member] | Natural gasoline [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price	[1]		41.84
DJ Basin Complex [Member] | Year 2017 [Member] | Condensate [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price	[1]		45.40
DJ Basin Complex [Member] | Year 2017 [Member] | Natural gas (per MMBtu) [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price | $ / MMBTU	[1]		3.05
MGR Assets [Member] | Years 2016 - 2017 [Member] | Ethane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		23.11
MGR Assets [Member] | Years 2016 - 2017 [Member] | Propane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		52.90
MGR Assets [Member] | Years 2016 - 2017 [Member] | Isobutane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		73.89
MGR Assets [Member] | Years 2016 - 2017 [Member] | Normal butane [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		64.93
MGR Assets [Member] | Years 2016 - 2017 [Member] | Natural gasoline [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		81.68
MGR Assets [Member] | Years 2016 - 2017 [Member] | Condensate [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price		81.68
MGR Assets [Member] | Years 2016 - 2017 [Member] | Natural gas (per MMBtu) [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price | $ / MMBTU		4.87
MGR Assets [Member] | Year 2017 [Member] | Ethane [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price	[2]		4.08
MGR Assets [Member] | Year 2017 [Member] | Propane [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price	[2]		19.24
MGR Assets [Member] | Year 2017 [Member] | Isobutane [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price	[2]		25.79
MGR Assets [Member] | Year 2017 [Member] | Normal butane [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price	[2]		25.16
MGR Assets [Member] | Year 2017 [Member] | Natural gasoline [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price	[2]		45.01
MGR Assets [Member] | Year 2017 [Member] | Condensate [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price	[2]		53.55
MGR Assets [Member] | Year 2017 [Member] | Natural gas (per MMBtu) [Member]
Commodity Price Risk Swap [Line Items]
Commodity market price | $ / MMBTU	[2]		3.05
[1]	Represents the New York Mercantile Exchange (“NYMEX”) forward strip price as of December 8, 2015 and December 1, 2016, for the 2016 Market Prices and 2017 Market Prices, respectively, 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 1, 2016, 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 Table (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Payable to affiliate	$ 186,882		$ 247,076
Partners’ capital adjustment	0	$ 714
Western Gas Partners, LP [Member] | Affiliates [Member] | Purchases [Member]
Related Party Transaction [Line Items]
Cash consideration - purchases	0	1,096
Payable to affiliate	0	990
Net carrying value	0	(1,372)
Partners’ capital adjustment	$ 0	$ 714

Transactions with Affiliates 43

Transactions with Affiliates - Summary of Affiliate Transactions Table (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Related Party Transaction [Line Items]
Revenues and other		$ 516,193	$ 383,141
Equity income, net – affiliates	[1]	19,461	16,814
Cost of product	[2]	189,359	76,467
Operation and maintenance	[2]	73,760	76,213
General and administrative	[2]	13,476	12,515
Operating expenses		523,333	247,158
Interest income	[3]	4,225	4,225
Interest expense	[4]	36,033	32,139
Distributions to unitholders	[5]	101,254	88,389
Above-market component of swap extensions with Anadarko	[5]	12,297	6,813
Affiliates [Member]
Related Party Transaction [Line Items]
Revenues and other	[1]	315,155	272,584
Cost of product	[1]	15,988	24,580
Operation and maintenance	[6]	17,089	17,975
General and administrative	[7]	9,734	9,150
Operating expenses		42,811	51,705
Interest expense	[8]	71	4,537
Affiliates [Member] | Western Gas Partners, LP [Member]
Related Party Transaction [Line Items]
Distributions to unitholders	[9]	1,730	606
Affiliates [Member] | Western Gas Equity Partners, LP [Member]
Related Party Transaction [Line Items]
Distributions to unitholders	[10]	$ 82,597	$ 77,152
[1]	Represents amounts earned or incurred on and subsequent to the date of the 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]	Cost of product includes product purchases from Anadarko (as defined in Note 1) of $16.0 million and $24.6 million for the three months ended March 31, 2017 and 2016, respectively. Operation and maintenance includes charges from Anadarko of $17.1 million and $18.0 million for the three months ended March 31, 2017 and 2016, respectively. General and administrative includes charges from Anadarko of $9.7 million and $9.2 million for the three months ended March 31, 2017 and 2016, respectively. See Note 5.
[3]	Represents interest income recognized on the note receivable from Anadarko.
[4]	Includes affiliate (as defined in Note 1) amounts of $(0.1) million and $(4.5) million for the three months ended March 31, 2017 and 2016, respectively. See Note 2 and Note 9.
[5]	See Note 5.
[6]	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.
[7]	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 Plan within this Note 5) and amounts charged by Anadarko under the WGP and WES omnibus agreements.
[8]	Includes amounts related to WES’s Deferred purchase price obligation - Anadarko (see Note 2 and Note 9).
[9]	Represents distributions paid to other subsidiaries of Anadarko under WES’s partnership agreement (see Note 3 and Note 4).
[10]	Represents distributions paid under WGP’s partnership agreement (see Note 3 and Note 4).

Transactions with Affiliates 44

Transactions with Affiliates - Additional Information (Details) - USD ($)		Nov. 01, 2012	May 31, 2008	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Note receivable - Anadarko				$ 260,000,000		$ 260,000,000
Above-market component of swap extensions with Anadarko	[1]			12,297,000
Contributions of equity-based compensation to WES by Anadarko				$ 1,125,000
Western Gas Equity Partners Long Term Incentive Plan [Member]
Related Party Transaction [Line Items]
Units vesting period				3 years
Equity-based compensation expense				$ 55,000	$ 56,000
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%
Independent Director [Member] | Western Gas Equity Partners Long Term Incentive Plan [Member]
Related Party Transaction [Line Items]
Units vesting period				1 year
Western Gas Partners, LP [Member] | Western Gas Equity Partners Long Term Incentive Plan [Member] | Anadarko Incentive Plan [Member]
Related Party Transaction [Line Items]
Equity-based compensation expense				$ 1,200,000	1,200,000
Contributions of equity-based compensation to WES by Anadarko				$ 1,119,000
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				32.00%	37.00%
Western Gas Partners, LP [Member] | Natural Gas [Member] | Processing [Member]
Related Party Transaction [Line Items]
Affiliate throughput percent				49.00%	61.00%
Western Gas Partners, LP [Member] | Crude Oil and NGL [Member] | Gathering, Treating and Transportation [Member]
Related Party Transaction [Line Items]
Affiliate throughput percent				56.00%	64.00%
Western Gas Partners, LP [Member] | Affiliates [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%
Western Gas Partners, LP [Member] | Affiliates [Member] | Level 2 Inputs [Member] | Market Approach Valuation Technique [Member]
Related Party Transaction [Line Items]
Fair value of the note receivable				$ 311,000,000		$ 313,300,000
Western Gas Partners, LP [Member] | Independent Director [Member] | Western Gas Partners Long Term Incentive Plan [Member]
Related Party Transaction [Line Items]
Units vesting period				1 year
[1]	See Note 5.

Property, Plant and Equipment -

Property, Plant and Equipment - Historical Cost Table (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 7,240,894	$ 6,861,942
Accumulated depreciation	1,974,081	1,812,010
Net property, plant and equipment	5,266,813	5,049,932
Western Gas Partners, LP [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	4,021	4,012
Western Gas Partners, LP [Member] | Gathering Systems and Processing Complexes [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 6,836,748	6,462,053
Western Gas Partners, LP [Member] | Gathering Systems and Processing Complexes [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Western Gas Partners, LP [Member] | Gathering Systems and Processing Complexes [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	$ 139,376	139,646
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	$ 230,898	226,626
Western Gas Partners, LP [Member] | Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 29,851	$ 29,605
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

Property, Plant and Equipment46

Property, Plant and Equipment - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Impairments	$ 164,742	$ 6,518	$ 15,500
Western Gas Partners, LP [Member] | Granger Complex [Member]
Property, Plant and Equipment [Line Items]
Impairments	158,800
Western Gas Partners, LP [Member] | Granger Complex [Member] | Fair Value Measurements Nonrecurring [Member] | Level 3 Inputs [Member] | Income Approach Valuation Technique [Member]
Property, Plant and Equipment [Line Items]
Estimated fair value	48,500
Western Gas Partners, LP [Member] | Equipment [Member]
Property, Plant and Equipment [Line Items]
Impairments	5,900		9,400
Western Gas Partners, LP [Member] | Granger Straddle Plant [Member]
Property, Plant and Equipment [Line Items]
Impairments	3,700
Western Gas Partners, LP [Member] | Granger Straddle Plant [Member] | Fair Value Measurements Nonrecurring [Member] | Level 3 Inputs [Member] | Income Approach Valuation Technique [Member]
Property, Plant and Equipment [Line Items]
Estimated salvage value	$ 600
Western Gas Partners, LP [Member] | Newcastle System [Member]
Property, Plant and Equipment [Line Items]
Impairments			6,100
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

Equity Investments - Equity Inv

Equity Investments - Equity Investments Table (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017		Mar. 31, 2016
Schedule of Equity Method Investments [Line Items]
Balance		$ 594,208
Investment earnings (loss), net of amortization	[1]	19,461		$ 16,814
Distributions		(19,114)		(19,855)
Distributions in excess of cumulative earnings		(3,453)	[2]	$ (4,784)
Balance		591,102
Western Gas Partners, LP [Member] | Fort Union [Member]
Schedule of Equity Method Investments [Line Items]
Balance		12,833
Investment earnings (loss), net of amortization		805
Distributions		(845)
Distributions in excess of cumulative earnings	[2]	0
Balance		12,793
Western Gas Partners, LP [Member] | White Cliffs [Member]
Schedule of Equity Method Investments [Line Items]
Balance		47,319
Investment earnings (loss), net of amortization		3,098
Distributions		(2,952)
Distributions in excess of cumulative earnings	[2]	(615)
Balance		46,850
Western Gas Partners, LP [Member] | Rendezvous [Member]
Schedule of Equity Method Investments [Line Items]
Balance		46,739
Investment earnings (loss), net of amortization		249
Distributions		(734)
Distributions in excess of cumulative earnings	[2]	(809)
Balance		45,445
Western Gas Partners, LP [Member] | Mont Belvieu JV [Member]
Schedule of Equity Method Investments [Line Items]
Balance		112,805
Investment earnings (loss), net of amortization		6,863
Distributions		(6,125)
Distributions in excess of cumulative earnings	[2]	0
Balance		113,543
Western Gas Partners, LP [Member] | Texas Express Gathering LLC [Member]
Schedule of Equity Method Investments [Line Items]
Balance		15,846
Investment earnings (loss), net of amortization		367
Distributions		(272)
Distributions in excess of cumulative earnings	[2]	0
Balance		15,941
Western Gas Partners, LP [Member] | Texas Express Pipeline LLC [Member]
Schedule of Equity Method Investments [Line Items]
Balance		189,194
Investment earnings (loss), net of amortization		4,276
Distributions		(4,339)
Distributions in excess of cumulative earnings	[2]	(851)
Balance		188,280
Western Gas Partners, LP [Member] | Front Range Pipeline LLC [Member]
Schedule of Equity Method Investments [Line Items]
Balance		169,472
Investment earnings (loss), net of amortization		3,803
Distributions		(3,847)
Distributions in excess of cumulative earnings	[2]	(1,178)
Balance		$ 168,250
[1]	Represents amounts earned or incurred on and subsequent to the date of the 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]	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 - Accounts Receivable, Net Table (Details) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Trade receivables, net		$ 152,467	$ 192,606
Other receivables, net		77	30,415
Total accounts receivable, net	[1]	$ 152,544	$ 223,021
[1]	Accounts receivable, net includes amounts receivable from affiliates (as defined in Note 1) of $60.2 million and $76.4 million as of March 31, 2017, and December 31, 2016, respectively. Accounts receivable, net as of December 31, 2016, also includes an insurance claim receivable related to an incident at the DBM complex. See Note 1.

Components of Working Capital49

Components of Working Capital - Other Current Assets Table (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Other Current Assets [Line Items]
Natural gas liquids inventory	$ 8,348	$ 7,126
Imbalance receivables	977	3,483
Prepaid insurance	1,713	2,889
Total other current assets	$ 11,038	$ 13,498

Components of Working Capital50

Components of Working Capital - Accrued Liabilities Table (Details) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Components Of Working Capital [Abstract]
Accrued interest expense		$ 45,585	$ 39,834
Short-term asset retirement obligations		6,678	3,114
Short-term remediation and reclamation obligations		630	630
Income taxes payable		1,430	1,006
Other accrued liabilities		3,760	606
Total accrued liabilities	[1]	$ 58,083	$ 45,190
[1]	Accrued liabilities includes affiliate amounts of $0.4 million and zero as of March 31, 2017, and December 31, 2016, respectively.

Debt and Interest Expense - Deb

Debt and Interest Expense - Debt Outstanding Table (Details) - USD ($)		Mar. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Total long-term debt principal		$ 3,148,000,000	$ 3,148,000,000
Carrying value		3,120,257,000	3,119,461,000
Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[1]	3,228,592,000	3,224,199,000
WGP RCF [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Principal		28,000,000	28,000,000
Carrying value		28,000,000	28,000,000
WGP RCF [Member] | Revolving Credit Facility [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[1]	28,000,000	28,000,000
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		494,999,000	494,734,000
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	[1]	537,815,000	536,252,000
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		668,688,000	668,634,000
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	[1]	688,423,000	681,723,000
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		349,311,000	349,188,000
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	[1]	351,970,000	351,531,000
Western Gas Partners, LP [Member] | Senior Notes [Member] | 5.450% Senior Notes due 2044 [Member]
Debt Instrument [Line Items]
Principal		600,000,000	600,000,000
Carrying value		593,152,000	593,132,000
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	[1]	614,253,000	615,753,000
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		491,196,000	490,971,000
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	[1]	494,066,000	492,499,000
Western Gas Partners, LP [Member] | Senior Notes [Member] | 4.650% Senior Notes due 2026 [Member]
Debt Instrument [Line Items]
Principal		500,000,000	500,000,000
Carrying value		494,911,000	494,802,000
Western Gas Partners, LP [Member] | Senior Notes [Member] | 4.650% Senior Notes due 2026 [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[1]	$ 514,065,000	$ 518,441,000
[1]	Fair value is measured using the market approach and Level 2 inputs.

Debt and Interest Expense - D52

Debt and Interest Expense - Debt Activity Table (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)
Debt Instrument [Line Items]
Beginning balance	$ 3,119,461
Ending balance	3,120,257
Western Gas Partners, LP [Member]
Debt Instrument [Line Items]
Other	$ 796

Debt and Interest Expense - Int

Debt and Interest Expense - Interest Expense Table (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Debt Instrument [Line Items]
Interest expense	[1]	$ (36,033)	$ (32,139)
Third Parties [Member]
Debt Instrument [Line Items]
Long-term debt		(34,814)	(27,856)
Amortization of debt issuance costs and commitment fees		(1,964)	(1,595)
Capitalized interest		816	1,849
Interest expense		(35,962)	(27,602)
Affiliates [Member]
Debt Instrument [Line Items]
Interest expense	[2]	(71)	(4,537)
Affiliates [Member] | Deferred Purchase Price Obligation - Anadarko [Member]
Debt Instrument [Line Items]
Deferred purchase price obligation - Anadarko	[3]	$ (71)	$ (4,537)
[1]	Includes affiliate (as defined in Note 1) amounts of $(0.1) million and $(4.5) million for the three months ended March 31, 2017 and 2016, respectively. See Note 2 and Note 9.
[2]	Includes amounts related to WES’s Deferred purchase price obligation - Anadarko (see Note 2 and Note 9).
[3]	See Note 2 for a discussion of the Deferred purchase price obligation - Anadarko.

Debt and Interest Expense - Add

Debt and Interest Expense - Additional Information (Details) - USD ($)	Nov. 01, 2012	Mar. 31, 2017	Mar. 31, 2016
Working Capital Facility [Member] | Affiliates [Member]
Debt Instrument [Line Items]
Facility, expiration date	Nov. 1, 2017
Facility, interest rate at period end		2.48%	1.94%
Facility, outstanding borrowings		$ 0
Facility, available borrowing capacity		$ 30,000,000
WGP RCF [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility, expiration date		Mar. 14, 2019
Facility, fee rate		0.30%	0.30%
Facility, interest rate at period end		2.99%	2.69%
Facility, outstanding borrowings		$ 28,000,000
Facility, available borrowing capacity		$ 222,000,000
Western Gas Partners, LP [Member] | WES RCF [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility, expiration date		Feb. 26, 2020
Facility, fee rate		0.20%	0.20%
Facility, interest rate at period end		2.28%	1.74%
Facility, outstanding borrowings		$ 0
Facility, available borrowing capacity		1,195,000,000
Outstanding letters of credit		$ 4,900,000
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
Western Gas Partners, LP [Member] | Senior Notes [Member] | 4.650% Senior Notes due 2026 [Member]
Debt Instrument [Line Items]
Fixed interest rate		4.65%
Debt instrument, maturity date		Jul. 1, 2026

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - Western Gas Partners, LP [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Loss Contingencies [Line Items]
Committed capital	$ 36.9
Rent expense associated with office, warehouse and equipment leases	$ 7.9	$ 8.9