Western Midstream Partners 10-Q 26 Jul 17 2017 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2017	Jul. 24, 2017
Document And Entity Information [Abstract]
Trading Symbol	WES
Entity Registrant Name	Western Gas Partners LP
Entity Central Index Key	1,414,475
Document Type	10-Q
Document Period End Date	Jun. 30, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Units Outstanding		152,602,105

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues and Other
Total revenues and other		$ 525,450	$ 428,664	$ 1,041,643	$ 811,805
Equity income, net – affiliates	[1]	21,728	19,693	41,189	36,507
Operating expenses
Cost of product	[2]	203,277	104,849	392,636	181,316
Operation and maintenance	[2]	76,148	75,173	149,908	151,386
General and administrative	[2]	10,585	10,883	23,244	22,160
Property and other taxes		11,924	12,078	24,218	22,428
Depreciation and amortization		74,031	67,305	143,733	132,400
Impairments		3,178	2,403	167,920	8,921
Total operating expenses		379,143	272,691	901,659	518,611
Gain (loss) on divestiture and other, net		15,458	(1,907)	134,945	(2,539)
Proceeds from business interruption insurance claims		24,115	2,603	29,882	2,603
Operating income (loss)		207,608	176,362	346,000	329,765
Interest income - affiliates	[3]	4,225	4,225	8,450	8,450
Interest expense	[4]	(35,746)	(12,883)	(71,250)	(44,919)
Other income (expense), net		253	(53)	683	71
Income (loss) before income taxes		176,340	167,651	283,883	293,367
Income tax (benefit) expense		843	326	4,395	6,959
Net income (loss)		175,497	167,325	279,488	286,408
Net income attributable to noncontrolling interest		2,046	2,804	4,148	5,827
Net income (loss) attributable to Western Gas Partners, LP		173,451	164,521	275,340	280,581
Limited partners' interest in net income (loss):
Pre-acquisition net (income) loss allocated to Anadarko		0	0	0	(11,326)
General partner interest in net (income) loss	[5]	$ (76,365)	$ (58,381)	$ (144,527)	$ (113,781)
Net income (loss) per common unit – basic and diluted	[6],[7]	$ 0.49	$ 0.55	$ 0.53	$ 0.86
Series A Preferred Units [Member]
Limited partners' interest in net income (loss):
Limited partners’ interest in net income (loss)	[8]	$ (14,199)	$ (23,121)	$ (42,373)	$ (25,450)
Common and Class C Units [Member]
Limited partners' interest in net income (loss):
Limited partners’ interest in net income (loss)	[5]	(82,887)	(83,019)	(88,440)	(130,024)
Affiliates [Member]
Revenues and Other
Gathering, processing and transportation		154,984	186,733	327,298	374,451
Natural gas and natural gas liquids sales		161,329	115,672	304,170	200,538
Total revenues and other	[1]	316,313	302,405	631,468	574,989
Operating expenses
Cost of product	[1]	21,607	22,145	37,595	46,725
Operation and maintenance	[9]	18,462	17,661	35,551	35,636
General and administrative	[10]	9,365	9,169	18,900	18,121
Total operating expenses		49,434	48,975	92,046	100,482
Interest expense	[11]	0	15,461	(71)	10,924
Third Parties [Member]
Revenues and Other
Gathering, processing and transportation		144,451	114,403	279,951	220,689
Natural gas and natural gas liquids sales		63,495	11,321	127,179	15,011
Other		1,191	535	3,045	1,116
Total revenues and other		209,137	126,259	410,175	236,816
Operating expenses
Interest expense		$ (35,746)	$ (28,344)	$ (71,179)	$ (55,843)
[1]	Represents amounts earned or incurred on and subsequent to the date of the acquisition of Partnership assets, as well as amounts earned or incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets, recognized under gathering, treating or processing agreements, and purchase and sale agreements.
[2]	Cost of product includes product purchases from Anadarko (as defined in Note 1) of $21.6 million and $37.6 million for the three and six months ended June 30, 2017, respectively, and $22.1 million and $46.7 million for the three and six months ended June 30, 2016, respectively. Operation and maintenance includes charges from Anadarko of $18.5 million and $35.6 million for the three and six months ended June 30, 2017, respectively, and $17.7 million and $35.6 million for the three and six months ended June 30, 2016, respectively. General and administrative includes charges from Anadarko of $9.4 million and $18.9 million for the three and six months ended June 30, 2017, respectively, and $9.2 million and $18.1 million for the three and six months ended June 30, 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 zero and $(0.1) million for the three and six months ended June 30, 2017, respectively, and $15.5 million and $10.9 million for the three and six months ended June 30, 2016, respectively. See Note 2 and Note 9.
[5]	Represents net income (loss) earned on and subsequent to the date of acquisition of the Partnership assets (as defined in Note 1). See Note 4.
[6]	See Note 4 for the calculation of net income (loss) per common unit.
[7]	The impact of Class C units and the conversion of Series A Preferred units would be anti-dilutive for all periods presented. As of May 2, 2017, all Series A Preferred units were converted into common units on a one-for-one basis.
[8]	Adjusted to reflect amortization of the beneficial conversion features.
[9]	Represents expenses incurred on and subsequent to the date of the acquisition of Partnership assets, as well as expenses incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets.
[10]	Represents general and administrative expense incurred on and subsequent to the date of the Partnership’s acquisition of the Partnership assets, as well as a management services fee for reimbursement of expenses incurred by Anadarko for periods prior to the acquisition of the Partnership assets by the Partnership. These amounts include equity-based compensation expense allocated to the Partnership by Anadarko (see WES LTIP and WGP LTIP and Anadarko Incentive Plan within this Note 5).
[11]	Includes amounts related to the Deferred purchase price obligation - Anadarko (see Note 2 and Note 9).

Consolidated Statements of Ope3

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Cost of product	[1]	$ 203,277	$ 104,849	$ 392,636	$ 181,316
Operation and maintenance	[1]	76,148	75,173	149,908	151,386
General and administrative	[1]	10,585	10,883	23,244	22,160
Interest expense	[2]	(35,746)	(12,883)	(71,250)	(44,919)
Affiliates [Member]
Cost of product	[3]	21,607	22,145	37,595	46,725
Operation and maintenance	[4]	18,462	17,661	35,551	35,636
General and administrative	[5]	9,365	9,169	18,900	18,121
Interest expense	[6]	$ 0	$ 15,461	$ (71)	$ 10,924
[1]	Cost of product includes product purchases from Anadarko (as defined in Note 1) of $21.6 million and $37.6 million for the three and six months ended June 30, 2017, respectively, and $22.1 million and $46.7 million for the three and six months ended June 30, 2016, respectively. Operation and maintenance includes charges from Anadarko of $18.5 million and $35.6 million for the three and six months ended June 30, 2017, respectively, and $17.7 million and $35.6 million for the three and six months ended June 30, 2016, respectively. General and administrative includes charges from Anadarko of $9.4 million and $18.9 million for the three and six months ended June 30, 2017, respectively, and $9.2 million and $18.1 million for the three and six months ended June 30, 2016, respectively. See Note 5.
[2]	Includes affiliate (as defined in Note 1) amounts of zero and $(0.1) million for the three and six months ended June 30, 2017, respectively, and $15.5 million and $10.9 million for the three and six months ended June 30, 2016, respectively. See Note 2 and Note 9.
[3]	Represents amounts earned or incurred on and subsequent to the date of the acquisition of Partnership assets, as well as amounts earned or incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets, recognized under gathering, treating or processing agreements, and purchase and sale agreements.
[4]	Represents expenses incurred on and subsequent to the date of the acquisition of Partnership assets, as well as expenses incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets.
[5]	Represents general and administrative expense incurred on and subsequent to the date of the Partnership’s acquisition of the Partnership assets, as well as a management services fee for reimbursement of expenses incurred by Anadarko for periods prior to the acquisition of the Partnership assets by the Partnership. These amounts include equity-based compensation expense allocated to the Partnership by Anadarko (see WES LTIP and WGP LTIP and Anadarko Incentive Plan within this Note 5).
[6]	Includes amounts related to the Deferred purchase price obligation - Anadarko (see Note 2 and Note 9).

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Jun. 30, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents		$ 188,197	$ 357,925
Accounts receivable, net	[1]	136,444	223,223
Other current assets		10,161	12,866
Total current assets		334,802	594,014
Note receivable - Anadarko		260,000	260,000
Property, plant and equipment
Cost		7,354,782	6,861,942
Less accumulated depreciation		2,006,988	1,812,010
Net property, plant and equipment		5,347,794	5,049,932
Goodwill		417,610	417,610
Other intangible assets		789,483	803,698
Equity investments		581,151	594,208
Other assets		14,875	13,566
Total assets		7,745,715	7,733,028
Current liabilities
Accounts and imbalance payables	[2]	198,496	247,076
Accrued ad valorem taxes		22,059	23,121
Accrued liabilities	[3]	56,840	45,108
Total current liabilities		277,395	315,305
Long-term debt		3,253,065	3,091,461
Deferred income taxes		10,169	6,402
Asset retirement obligations and other		142,526	142,641
Deferred purchase price obligation - Anadarko	[4]	0	41,440
Total long-term liabilities		3,405,760	3,281,944
Total liabilities		3,683,155	3,597,249
Equity and partners' capital
General partner units (2,583,068 units issued and outstanding at June 30, 2017, and December 31, 2016)		165,442	143,968
Total partners' capital		4,000,224	4,071,216
Noncontrolling interest		62,336	64,563
Total equity and partners' capital		4,062,560	4,135,779
Total liabilities, equity and partners' capital		7,745,715	7,733,028
Series A Preferred Units [Member]
Equity and partners' capital
Series A Preferred units, Common units and Class C units	[5]	0	639,545
Common Units [Member]
Equity and partners' capital
Series A Preferred units, Common units and Class C units		3,070,608	2,536,872
Class C Units [Member]
Equity and partners' capital
Series A Preferred units, Common units and Class C units	[6]	$ 764,174	$ 750,831
[1]	Accounts receivable, net includes amounts receivable from affiliates (as defined in Note 1) of $63.0 million and $76.6 million as of June 30, 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]	Accounts and imbalance payables includes affiliate amounts of $0.2 million and zero as of June 30, 2017, and December 31, 2016, respectively.
[3]	Accrued liabilities includes affiliate amounts of $0.3 million and zero as of June 30, 2017, and December 31, 2016, respectively.
[4]	See Note 2.
[5]	The Series A Preferred units converted into common units on a one-for-one basis in 2017. See Note 4.
[6]	The Class C units will convert into common units on a one-for-one basis on March 1, 2020, unless the Partnership elects to convert such units earlier or Anadarko extends the conversion date. See Note 4.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands		Jun. 30, 2017	Dec. 31, 2016
General partner units issued		2,583,068	2,583,068
General partner units outstanding		2,583,068	2,583,068
Accounts receivable, net	[1]	$ 136,444	$ 223,223
Accounts and imbalance payables	[2]	198,496	247,076
Accrued liabilities	[3]	56,840	45,108
Affiliates [Member]
Accounts receivable, net		63,000	76,600
Accounts and imbalance payables		200	0
Accrued liabilities		$ 300	$ 0
Series A Preferred Units [Member]
Units issued		0	21,922,831
Units outstanding		0	21,922,831
Series A Preferred units, common units issued upon conversion		1
Common Units [Member]
Units issued		152,602,105	130,671,970
Units outstanding		152,602,105	130,671,970
Class C Units [Member]
Units issued		12,743,318	12,358,123
Units outstanding		12,743,318	12,358,123
Class C units, common units issued upon conversion		1
[1]	Accounts receivable, net includes amounts receivable from affiliates (as defined in Note 1) of $63.0 million and $76.6 million as of June 30, 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]	Accounts and imbalance payables includes affiliate amounts of $0.2 million and zero as of June 30, 2017, and December 31, 2016, respectively.
[3]	Accrued liabilities includes affiliate amounts of $0.3 million and zero as of June 30, 2017, and December 31, 2016, respectively.

Consolidated Statement of Equit

Consolidated Statement of Equity and Partners' Capital - 6 months ended Jun. 30, 2017 - USD ($) $ in Thousands		Total	Net Investment by Anadarko [Member]	Common Units [Member]	Class C Units [Member]	Series A Preferred Units [Member]	General Partner Units [Member]	Noncontrolling Interest [Member]
Balance at Dec. 31, 2016		$ 4,135,779	$ 0	$ 2,536,872	$ 750,831	$ 639,545	$ 143,968	$ 64,563
Net income (loss)		279,488	0	112,818	10,542	7,453	144,527	4,148
Above-market component of swap agreements with Anadarko	[1]	28,670		28,670
Conversion of Series A Preferred units into common units	[2]	0		686,936		(686,936)
Amortization of beneficial conversion feature of Class C units and Series A Preferred units		0		(65,100)	2,801	62,299
Distributions to noncontrolling interest owner		(6,375)						(6,375)
Distributions to unitholders		(381,771)		(236,307)		(22,361)	(123,103)
Acquisitions from affiliates		0	(30)	30
Revision to Deferred purchase price obligation – Anadarko	[3]	4,165		4,165
Contributions of equity-based compensation from Anadarko		2,236		2,192			44
Net pre-acquisition contributions from (distributions to) Anadarko		30	30
Net contributions from (distributions to) Anadarko of other assets		376		370			6
Other		(38)		(38)
Balance at Jun. 30, 2017		$ 4,062,560	$ 0	$ 3,070,608	$ 764,174	$ 0	$ 165,442	$ 62,336
[1]	See Note 5.
[2]	See Note 4.
[3]	See Note 2.

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2017		Jun. 30, 2016
Cash flows from operating activities
Net income (loss)		$ 279,488		$ 286,408
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization		143,733		132,400
Impairments		167,920		8,921
Non-cash equity-based compensation expense		2,393		2,391
Deferred income taxes		3,767		1,980
Accretion and amortization of long-term obligations, net		2,139		(9,055)
Equity income, net – affiliates	[1]	(41,189)		(36,507)
Distributions from equity investment earnings – affiliates		42,202		38,519
(Gain) loss on divestiture and other, net		(134,945)		2,539
Lower of cost or market inventory adjustments		140		0
Changes in assets and liabilities:
(Increase) decrease in accounts receivable, net		9,363		(33,242)
Increase (decrease) in accounts and imbalance payables and accrued liabilities, net		(41,975)		(2,227)
Change in other items, net		116		1,739
Net cash provided by operating activities		433,152		393,866
Cash flows from investing activities
Capital expenditures		(260,480)		(255,923)
Investments in equity affiliates		(287)		139
Distributions from equity investments in excess of cumulative earnings – affiliates		9,221	[2]	10,611
Proceeds from property insurance claims		22,977		2,944
Net cash used in investing activities		(363,131)		(952,824)
Cash flows from financing activities
Borrowings, net of debt issuance costs		159,989		530,000
Repayments of debt		0		(290,000)
Increase (decrease) in outstanding checks		(2,763)		(1,314)
Proceeds from the issuance of common units, net of offering expenses		(183)		25,000
Distributions to unitholders	[3]	(381,771)		(313,380)
Distributions to noncontrolling interest owner		(6,375)		(7,460)
Net contributions from (distributions to) Anadarko		30		(27,459)
Above-market component of swap agreements with Anadarko	[3]	28,670		16,365
Net cash provided by (used in) financing activities		(239,749)		618,692
Net increase (decrease) in cash and cash equivalents		(169,728)		59,734
Cash and cash equivalents at beginning of period		357,925		98,033
Cash and cash equivalents at end of period		188,197		157,767
Supplemental disclosures
Accretion expense and revisions to the Deferred purchase price obligation – Anadarko	[4]	(4,094)		(159,524)
Net distributions to (contributions from) Anadarko of other assets		(376)		354
Interest paid, net of capitalized interest		68,396		53,973
Taxes paid (reimbursements received)		189		67
Accrued capital expenditures		100,038		70,725
Fair value of properties and equipment from non-cash third party transactions	[4]	551,453		0
Series A Preferred Units [Member]
Cash flows from financing activities
Proceeds from the issuance of Series A Preferred units, net of offering expenses		0		686,940
Affiliates [Member]
Cash flows from investing activities
Contributions in aid of construction costs from affiliates		1,343		3,854
Acquisitions		(3,910)		(715,199)
Proceeds from the sale of assets		0		613
Cash flows from financing activities
Settlement of the Deferred purchase price obligation - Anadarko	[4]	(37,346)		0
Proceeds from the issuance of common units, net of offering expenses	[5]	0		25,000
Distributions to unitholders	[6]	(213,572)		(184,678)
Third Parties [Member]
Cash flows from investing activities
Acquisitions		(155,287)		0
Proceeds from the sale of assets		$ 23,292		$ 137
[1]	Represents amounts earned or incurred on and subsequent to the date of the acquisition of Partnership assets, as well as amounts earned or incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets, recognized under gathering, treating or processing agreements, and purchase and sale agreements.
[2]	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 proceeds from the issuance of 835,841 common units to WGP as partial funding for the acquisition of Springfield (see Note 2).
[6]	Represents distributions paid under the partnership agreement (see Note 3 and Note 4).

Description of Business and Bas

Description of Business and Basis of Presentation	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Description of Business and Basis of Presentation	General. Western Gas Partners, LP is a growth-oriented Delaware master limited partnership (“MLP”) formed by Anadarko Petroleum Corporation in 2007 to acquire, own, develop and operate midstream energy assets. For purposes of these consolidated financial statements, the “Partnership” refers to Western Gas Partners, LP and its subsidiaries. The Partnership’s general partner, Western Gas Holdings, LLC (the “general partner”), is owned by Western Gas Equity Partners, LP (“WGP”), a Delaware MLP formed by Anadarko Petroleum Corporation in September 2012 to own the Partnership’s general partner, as well as a significant limited partner interest in the Partnership. WGP has no independent operations or material assets other than owning the partnership interests in the Partnership (see Holdings of Partnership equity in Note 4 ). Western Gas Equity Holdings, LLC is WGP’s general partner and is a wholly owned subsidiary of Anadarko Petroleum Corporation. “Anadarko” refers to Anadarko Petroleum Corporation and its subsidiaries, excluding the Partnership and the general partner, and “affiliates” refers to subsidiaries of Anadarko, excluding the Partnership, but including equity interests in Fort Union Gas Gathering, LLC (“Fort Union”), White Cliffs Pipeline, LLC (“White Cliffs”), Rendezvous Gas Services, LLC (“Rendezvous”), Enterprise EF78 LLC (the “Mont Belvieu JV”), Texas Express Pipeline LLC (“TEP”), Texas Express Gathering LLC (“TEG”) and Front Range Pipeline LLC (“FRP”). The interests in TEP, TEG and FRP are referred to collectively as the “TEFR Interests.” “MGR assets” refers to the Red Desert complex and the Granger straddle plant. The Partnership is engaged in the business of gathering, compressing, treating, processing and transporting natural gas; gathering, stabilizing and transporting condensate, natural gas liquids (“NGLs”) and crude oil; and gathering and disposing of produced water. The Partnership provides these midstream services for Anadarko, as well as for third-party producers and customers. As of June 30, 2017 , the Partnership’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 19 3 — 3 Natural gas processing plants/trains 19 5 — 2 NGL pipelines 2 — — 3 Natural gas pipelines 5 — — — Oil pipelines — 1 — 1 These assets and investments are located in the Rocky Mountains (Colorado, Utah and Wyoming), North-central Pennsylvania and Texas. During the second quarter of 2017, the Partnership commenced operation of two produced-water disposal systems in West Texas, which are included within Gathering systems in the table above. 1. DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (CONTINUED) Basis of presentation. The following table outlines the Partnership’s ownership interests and the accounting method of consolidation used in the Partnership’s consolidated financial statements: Percentage Interest Equity investments (1) Fort Union 14.81 % White Cliffs 10 % Rendezvous 22 % Mont Belvieu JV 25 % TEP 20 % TEG 20 % FRP 33.33 % Proportionate consolidation (2) 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 the Partnership exercises significant influence are accounted for under the equity method. “Equity investment throughput” refers to the Partnership’s share of average throughput for these investments. (2) The Partnership proportionately consolidates its associated share of the assets, liabilities, revenues and expenses attributable to these assets. (3) The 25% interest in Chipeta Processing LLC (“Chipeta”) held by a third-party member is reflected within noncontrolling interest in the consolidated financial statements. (4) The Partnership 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 the Partnership and entities in which it holds a controlling financial interest. 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 the Partnership’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. Presentation of Partnership assets. The term “Partnership assets” includes both the assets owned and the interests accounted for under the equity method (see Note 7 ) by the Partnership as of June 30, 2017 . Because Anadarko controls the Partnership through its ownership and control of WGP, which owns the Partnership’s entire general partner interest, each acquisition of Partnership assets from Anadarko has been considered a transfer of net assets between entities under common control. As such, the Partnership assets acquired from Anadarko were initially recorded at Anadarko’s historic carrying value, which did not correlate to the total acquisition price paid by the Partnership. Further, after an acquisition of Partnership assets from Anadarko, the Partnership may be required to recast its financial statements to include the activities of such Partnership assets from the date of common control. 1. DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (CONTINUED) For those periods requiring recast, the consolidated financial statements for periods prior to the Partnership’s acquisition of the Partnership 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 the Partnership had owned the Partnership assets during the periods reported. Net income (loss) attributable to the Partnership assets acquired from Anadarko for periods prior to the Partnership’s acquisition of the Partnership assets is not allocated to the limited partners. Use of estimates. 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. 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 Delaware Basin Midstream, LLC (“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. During 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 the Partnership’s estimate of the amount that will be recovered under the property insurance claim based on further discussions with insurers. During the second quarter of 2017, the Partnership reached a settlement with insurers and final proceeds were received. As of June 30, 2017 , and December 31, 2016 , the consolidated balance sheets include receivables of zero and $30.0 million , respectively, for the property insurance claim related to the incident at the DBM complex. During the six months ended June 30, 2017 , the Partnership received $52.9 million in cash proceeds from insurers in final settlement of the Partnership’s claims related to the incident at the DBM complex, including $29.9 million in proceeds from business interruption insurance claims and $23.0 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. The Partnership’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. 1. DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (CONTINUED) 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. The Partnership adopted this ASU on January 1, 2017, using a modified retrospective approach, with no impact to its consolidated financial statements. 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. The Partnership will adopt this ASU on January 1, 2018, and does not expect the adoption to have a material impact 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. The Partnership will adopt this ASU on January 1, 2018, and does not expect the adoption 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, and a modified retrospective approach is required for all comparative periods presented. The Partnership plans to elect certain practical expedients when implementing the new lease standard, which means the Partnership will not have to reassess the accounting for contracts that commenced prior to adoption . The Partnership is continuing to analyze its portfolio of contracts to assess the application of this ASU to certain types of contracts, its current business processes and the impact that adoption will 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. The Partnership 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. The Partnership 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. The Partnership 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. The Partnership will adopt this 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	6 Months Ended
	Jun. 30, 2017
Property, Plant and Equipment [Abstract]
Acquisitions and Divestitures	2. ACQUISITIONS AND DIVESTITURES The following table presents the acquisitions completed by the Partnership 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 Common Units Issued 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) The Partnership acquired Springfield Pipeline LLC (“Springfield”) from Anadarko for $750.0 million , consisting of $712.5 million in cash and the issuance of 1,253,761 of the Partnership’s common units. Springfield owns a 50.1% interest in an oil gathering system and a gas gathering system, such interest being referred to in this report as the “Springfield interest.” The Springfield oil and gas gathering systems (collectively, the “Springfield system”) are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. The Partnership financed the cash portion of the acquisition through: (i) borrowings of $247.5 million on the Partnership’s senior unsecured revolving credit facility (“RCF”), (ii) the issuance of 835,841 of the Partnership’s common units to WGP and (iii) the issuance of Series A Preferred units to private investors. See Note 4 for further information regarding the Series A Preferred units. (2) The Partnership acquired the Additional DBJV System Interest from a third party. See Property exchange below. Property exchange. On March 17, 2017, the Partnership acquired the Additional DBJV System Interest from a third party in exchange for (a) the Partnership’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”). The Partnership 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 $125.7 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 Partnership’s 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. Prior to the Partnership’s agreement with Anadarko to settle its deferred purchase price obligation early, the consideration that would have been paid by the Partnership for the March 2015 acquisition of Delaware Basin JV Gathering LLC (“DBJV”) from Anadarko, consisted of a cash payment to Anadarko due on March 31, 2020. The cash payment would have been equal to (a) eight multiplied by the average of the Partnership’s share in the Net Earnings (see definition below) of DBJV for the calendar years 2018 and 2019, less (b) the Partnership’s share of all capital expenditures incurred for DBJV between March 1, 2015, and February 29, 2020. Net Earnings was defined as all revenues less cost of product, operating expenses and property taxes, in each case attributable to DBJV on an accrual basis. In May 2017, the Partnership reached an agreement with Anadarko to settle this obligation whereby the Partnership made a cash payment to Anadarko of $37.3 million , equal to the net present value of the obligation at March 31, 2017. 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 Settlement of the Deferred purchase price obligation – Anadarko (37,346 ) Balance at June 30, 2017 $ — $ — (1) Calculated using Level 3 inputs. (2) Accretion expense was recorded as a charge to Interest expense in the consolidated statements of operations. (3) Recorded as revisions within Common units in the consolidated balance sheet and consolidated statement of equity and partners’ capital. Helper and Clawson systems divestiture. During the second quarter of 2017, the Helper and Clawson systems, located in Utah, were sold to a third party, resulting in a net gain on sale of $16.3 million recorded as Gain (loss) on divestiture and other, net in the consolidated statements of operations. 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. The Partnership allocated $1.6 million in goodwill to this divestiture.

Partnership Distributions

Partnership Distributions	6 Months Ended
	Jun. 30, 2017
Distributions Made to Members or Limited Partners [Abstract]
Partnership Distributions	3. PARTNERSHIP DISTRIBUTIONS The partnership agreement requires the Partnership to distribute all of its available cash (as defined in the partnership agreement) to unitholders of record on the applicable record date within 45 days of the end of each quarter. The Board of Directors of the Partnership’s general partner (the “Board of Directors”) declared the following cash distributions to the Partnership’s common and general partner unitholders for the periods presented: thousands except per-unit amounts Quarters Ended Total Quarterly Distribution per Unit Total Quarterly Cash Distribution Date of Distribution 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 $ 0.875 $ 188,753 May 2017 June 30 (1) 0.890 207,491 August 2017 (1) The Board of Directors declared a cash distribution to the Partnership’s unitholders for the second quarter of 2017 of $0.890 per unit, or $207.5 million in aggregate, including incentive distributions, but excluding distributions on Class C units (see Class C unit distributions below). The cash distribution is payable on August 11, 2017 , to unitholders of record at the close of business on July 31, 2017 . Available cash. The amount of available cash (as defined in the partnership agreement) generally is all cash on hand at the end of the quarter, plus, at the discretion of the general partner, working capital borrowings made subsequent to the end of such quarter, less the amount of cash reserves established by the Partnership’s general partner to provide for the proper conduct of the Partnership’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 its unitholders and to its general partner 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. Class C unit distributions. The Class C units receive quarterly distributions at a rate equivalent to the Partnership’s common units. The distributions are paid in the form of additional Class C units (“PIK Class C units”) until the scheduled conversion date on March 1, 2020 (unless earlier converted), and the Class C units are disregarded with respect to distributions of the Partnership’s available cash until they are converted to common units. The number of additional PIK Class C units to be issued in connection with a distribution payable on the Class C units is determined by dividing the corresponding distribution attributable to the Class C units by the volume-weighted-average price of the Partnership’s common units for the ten days immediately preceding the payment date for the common unit distribution, less a 6% discount. The Partnership records the PIK Class C unit distributions at fair value at the time of issuance. This Level 2 fair value measurement uses the Partnership’s unit price as a significant input in the determination of the fair value. See Note 4 for further discussion of the Class C units. 3. PARTNERSHIP DISTRIBUTIONS (CONTINUED) Series A Preferred unit distributions. As further described in Note 4 , the Partnership issued Series A Preferred units representing limited partner interests in the Partnership to private investors in 2016. The Series A Preferred unitholders received 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 $ 0.68 $ 7,453 May 2017 (1) Quarterly per unit distribution prorated for the 18 -day period during which 14,030,611 Series A Preferred units were outstanding during the first quarter of 2016. (2) Full quarterly per unit distribution on 14,030,611 Series A Preferred units and quarterly per unit distribution prorated for the 77 -day period during which 7,892,220 Series A Preferred units were outstanding during the second quarter of 2016. On March 1, 2017, 50% of the outstanding Series A Preferred units converted into common units on a one -for-one basis, and on May 2, 2017, the remaining Series A Preferred units converted into common units on a one -for-one basis. Such converted common units are entitled to distributions made to common unitholders with respect to the quarter during which the applicable conversion occurred and does not include a prorated Series A Preferred unit distribution. General partner interest and incentive distribution rights. As of June 30, 2017 , the general partner was entitled to 1.5% of all quarterly distributions that the Partnership 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 the general partner may receive on common units that it may acquire.

Equity and Partners' Capital

Equity and Partners' Capital	6 Months Ended
	Jun. 30, 2017
Partners' Capital Notes [Abstract]
Equity and Partners' Capital	4. EQUITY AND PARTNERS’ CAPITAL Class C units. In November 2014, the Partnership issued 10,913,853 Class C units to Anadarko Midstream Holdings, LLC (“AMH”), pursuant to a Unit Purchase Agreement with Anadarko and AMH. The Class C units were issued to partially fund the acquisition of DBM. When issued, the Class C units were scheduled to convert into common units on a one -for-one basis on December 31, 2017. In February 2017, Anadarko elected to extend the conversion date of the Class C units to March 1, 2020. The Partnership can elect to convert the Class C units earlier or Anadarko can extend the conversion date again. The Class C units were issued at a discount to the then-current market price of the common units into which they are convertible. This discount, totaling $34.8 million , represents a beneficial conversion feature, and at issuance, was reflected as an increase in common unitholders’ capital and a decrease in Class C unitholder capital to reflect the fair value of the Class C units at issuance. The beneficial conversion feature is considered a non-cash distribution that is recognized from the date of issuance through the date of conversion, resulting in an increase in Class C unitholder capital and a decrease in common unitholders’ capital as amortized. The beneficial conversion feature is amortized assuming the extended conversion date of March 1, 2020, using the effective yield method. The impact of the beneficial conversion feature amortization is also included in the calculation of earnings per unit. 4. EQUITY AND PARTNERS’ CAPITAL (CONTINUED) Series A Preferred units. In 2016, the Partnership issued 21,922,831 Series A Preferred units to private investors. Pursuant to an agreement between the Partnership and the holders of the Series A Preferred units, 50% of the Series A Preferred units converted into common units on a one -for-one basis on March 1, 2017, and the remaining Series A Preferred units converted on a one -for-one basis on May 2, 2017. The Partnership has an effective registration statement with the SEC relating to the public resale of the common units issued upon conversion of the Series A Preferred units. The Series A Preferred units were issued at a discount to the then-current market price of the common units into which they were convertible. This discount, totaling $93.4 million , represented a beneficial conversion feature, and at issuance, was reflected as an increase in common unitholders’ capital and a decrease in Series A Preferred unitholders’ capital to reflect the fair value of the Series A Preferred units on the date of issuance. The beneficial conversion feature was considered a non-cash distribution that was recognized from the date of issuance through the date of conversion, resulting in an increase in Series A Preferred unitholders’ capital and a decrease in common unitholders’ capital as amortized. The beneficial conversion feature was amortized using the effective yield method. The impact of the beneficial conversion feature amortization is also included in the calculation of earnings per unit. For the six months ended June 30, 2017, the amortization for the beneficial conversion feature of the Series A Preferred units was $62.3 million . Partnership interests. The Partnership’s common units are listed on the New York Stock Exchange under the symbol “WES.” The following table summarizes the common, Class C, Series A Preferred and general partner units issued during the six months ended June 30, 2017 : Common Units Class C Units Series A Preferred Units 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 — 385,195 — — 385,195 Conversion of Series A Preferred units 21,922,831 — (21,922,831 ) — — Long-Term Incentive Plan award vestings 7,304 — — — 7,304 Balance at June 30, 2017 152,602,105 12,743,318 — 2,583,068 167,928,491 Holdings of Partnership equity. As of June 30, 2017 , WGP held 50,132,046 common units, representing a 29.9% limited partner interest in the Partnership, and, through its ownership of the general partner, WGP indirectly held 2,583,068 general partner units, representing a 1.5% general partner interest in the Partnership, and 100% of the incentive distribution rights. As of June 30, 2017 , other subsidiaries of Anadarko collectively held 2,011,380 common units and 12,743,318 Class C units, representing an aggregate 8.8% limited partner interest in the Partnership. As of June 30, 2017 , the public held 100,458,679 common units, representing a 59.8% limited partner interest in the Partnership. 4. EQUITY AND PARTNERS’ CAPITAL (CONTINUED) Net income (loss) per unit for common units. Net income (loss) attributable to the Partnership assets acquired from Anadarko for periods prior to the Partnership’s acquisition of the Partnership assets is not allocated to the unitholders for purposes of calculating net income (loss) per common unit. Net income (loss) attributable to Western Gas Partners, LP earned on and subsequent to the date of acquisition of the Partnership assets is allocated as follows: General partner. The general partner’s allocation is equal to cash distributions plus its portion of undistributed earnings or losses. Specifically, net income equal to the amount of available cash (as defined by the partnership agreement) is allocated to the general partner consistent with actual cash distributions and capital account allocations, including incentive distributions. Undistributed earnings (net income in excess of distributions) or undistributed losses (available cash in excess of net income) are then allocated to the general partner in accordance with its weighted-average ownership percentage during each period. Series A Preferred unitholders. The Series A Preferred units were not considered a participating security as they only had distribution rights up to the specified per-unit quarterly distribution and had no rights to the Partnership’s undistributed earnings and losses. As such, the Series A Preferred unitholders’ allocation was equal to their cash distribution plus the amortization of the Series A Preferred units beneficial conversion feature (see Series A Preferred units above). Common and Class C unitholders. The Class C units are considered a participating security because they participate in distributions with common units according to a predetermined formula (see Note 3 ). The common and Class C unitholders’ allocation is equal to their cash distributions plus their respective portions of undistributed earnings or losses. Specifically, net income equal to the amount of available cash (as defined by the partnership agreement) is allocated to the common and Class C unitholders consistent with actual cash distributions and capital account allocations. Undistributed earnings or undistributed losses are then allocated to the common and Class C unitholders in accordance with their respective weighted-average ownership percentages during each period. The common unitholder allocation also includes the impact of the amortization of the Series A Preferred units and Class C units beneficial conversion features. The Class C unitholder allocation is similarly impacted by the amortization of the Class C units beneficial conversion feature (see Class C units above). Calculation of net income (loss) per unit. Basic net income (loss) per common unit is calculated by dividing the net income (loss) attributable to common unitholders by the weighted-average number of common units outstanding during the period. The common units issued in connection with acquisitions and equity offerings are included on a weighted-average basis for periods they were outstanding. Diluted net income (loss) per common unit is calculated by dividing the sum of (i) the net income (loss) attributable to common units adjusted for distributions on the Series A Preferred units and a reallocation of the common and Class C limited partners’ interest in net income (loss) assuming conversion of the Series A Preferred units into common units, and (ii) the net income (loss) attributable to the Class C units as a participating security, by the sum of the weighted-average number of common units outstanding plus the dilutive effect of (i) the weighted-average number of outstanding Class C units and (ii) the weighted-average number of common units outstanding assuming conversion of the Series A Preferred units. 4. EQUITY AND PARTNERS’ CAPITAL (CONTINUED) The following table illustrates the Partnership’s calculation of net income (loss) per unit for common units: Three Months Ended Six Months Ended thousands except per-unit amounts 2017 2016 2017 2016 Net income (loss) attributable to Western Gas Partners, LP $ 173,451 $ 164,521 $ 275,340 $ 280,581 Pre-acquisition net (income) loss allocated to Anadarko — — — (11,326 ) Series A Preferred units interest in net (income) loss (1) (14,199 ) (23,121 ) (42,373 ) (25,450 ) General partner interest in net (income) loss (76,365 ) (58,381 ) (144,527 ) (113,781 ) Common and Class C limited partners’ interest in net income (loss) $ 82,887 $ 83,019 $ 88,440 $ 130,024 Net income (loss) allocable to common units (1) $ 73,383 $ 71,622 $ 75,097 $ 111,184 Net income (loss) allocable to Class C units (1) 9,504 11,397 13,343 18,840 Common and Class C limited partners’ interest in net income (loss) $ 82,887 $ 83,019 $ 88,440 $ 130,024 Net income (loss) per unit Common units – basic and diluted (2) $ 0.49 $ 0.55 $ 0.53 $ 0.86 Weighted-average units outstanding Common units – basic and diluted 148,864 130,669 141,696 129,830 Excluded due to anti-dilutive effect: Class C units (2) 12,650 11,849 12,552 11,719 Series A Preferred units assuming conversion to common units (2) 3,734 20,709 10,901 11,742 (1) Adjusted to reflect amortization of the beneficial conversion features. (2) The impact of Class C units and the conversion of Series A Preferred units would be anti-dilutive for all periods presented. As of May 2, 2017, all Series A Preferred units were converted into common units on a one -for-one basis.

Transactions with Affiliates

Transactions with Affiliates	6 Months Ended
	Jun. 30, 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 the Partnership from services provided to Anadarko as well as from the sale of residue and NGLs to Anadarko. In addition, the Partnership purchases natural gas from an affiliate of Anadarko pursuant to gas purchase agreements. Operation and maintenance expense includes amounts accrued for or paid to affiliates for the operation of the Partnership assets, whether in providing services to affiliates or to third parties, including field labor, measurement and analysis, and other disbursements. A portion of the Partnership’s general and administrative expenses is paid by Anadarko, which results in affiliate transactions pursuant to the reimbursement provisions of the Partnership’s omnibus agreement. Affiliate expenses do not bear a direct relationship to affiliate revenues, and third-party expenses do not bear a direct relationship to third-party revenues. See Note 2 for further information related to contributions of assets to the Partnership by Anadarko. Cash management. Anadarko operates a cash management system whereby excess cash from most of its subsidiaries’ separate bank accounts is generally swept to centralized accounts. Prior to the Partnership’s acquisition of the Partnership assets, third-party sales and purchases related to such assets were received or paid in cash by Anadarko within its centralized cash management system. The outstanding affiliate balances were entirely settled through an adjustment to net investment by Anadarko in connection with the acquisition of the Partnership assets. Subsequent to the acquisition of Partnership assets from Anadarko, transactions related to such assets are cash-settled directly with third parties and with Anadarko affiliates. Chipeta cash settles its transactions directly with third parties and Anadarko, as well as with the other subsidiaries of the Partnership. Note receivable - Anadarko. Concurrently with the closing of the Partnership’s May 2008 initial public offering, the Partnership loaned $260.0 million to Anadarko in exchange for a 30-year note bearing interest at a fixed annual rate of 6.50% , payable quarterly. The fair value of the note receivable from Anadarko was $311.3 million and $313.3 million at June 30, 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. Commodity price swap agreements. The Partnership 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 Six Months Ended thousands 2017 2016 2017 2016 Gains (losses) on commodity price swap agreements related to sales: (1) Natural gas sales $ 4,656 $ 5,202 $ 5,738 $ 12,243 Natural gas liquids sales 1,837 20,480 (2,470 ) 40,550 Total 6,493 25,682 3,268 52,793 Gains (losses) on commodity price swap agreements related to purchases (2) (5,507 ) (16,913 ) (2,811 ) (35,784 ) Net gains (losses) on commodity price swap agreements $ 986 $ 8,769 $ 457 $ 17,009 (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. The Partnership also records a capital contribution from Anadarko in the Partnership’s consolidated statement of equity and partners’ capital for the amount by which the swap price exceeds the applicable market price in the tables below. The commodity price swap agreement for the Hugoton system was in place until its divestiture in October 2016. For the six months ended June 30, 2017 , the capital contribution from Anadarko was $28.7 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. The Partnership has significant gathering and processing arrangements with affiliates of Anadarko on a majority of its systems. The Partnership’s natural gas gathering, treating and transportation throughput (excluding equity investment throughput) attributable to production owned or controlled by Anadarko was 38% and 34% for the three and six months ended June 30, 2017 , respectively, and 39% and 38% for the three and six months ended June 30, 2016 , respectively. The Partnership’s natural gas processing throughput (excluding equity investment throughput) attributable to production owned or controlled by Anadarko was 39% and 44% for the three and six months ended June 30, 2017 , respectively, and 55% and 58% for the three and six months ended June 30, 2016 , respectively. The Partnership’s crude, NGL and produced water gathering, treating and transportation throughput (excluding equity investment throughput) attributable to production owned or controlled by Anadarko was 41% and 47% for the three and six months ended June 30, 2017 , respectively, and 64% for the three and six months ended June 30, 2016 . Commodity purchase and sale agreements. The Partnership sells a significant amount of its natural gas, condensate and NGLs to Anadarko Energy Services Company (“AESC”), Anadarko’s marketing affiliate. In addition, the Partnership purchases natural gas, condensate and NGLs from AESC pursuant to purchase agreements. The Partnership’s purchase and sale agreements with AESC are generally one-year contracts, subject to annual renewal. Acquisitions from Anadarko. On March 14, 2016, the Partnership acquired Springfield from Anadarko (see Note 2 ). 5. TRANSACTIONS WITH AFFILIATES (CONTINUED) WES LTIP. The general partner awards phantom units under the Western Gas Partners, LP 2008 Long-Term Incentive Plan (“WES LTIP”) primarily to its independent directors, but also from time to time to its executive officers and Anadarko employees performing services for the Partnership. The phantom units awarded to the independent directors vest one year from the grant date, while all other awards are subject to graded vesting over a three -year service period. Compensation expense is recognized over the vesting period and was $0.1 million for each of the three months ended June 30, 2017 and 2016 , and $0.2 million for each of the six months ended June 30, 2017 and 2016 . WGP LTIP and Anadarko Incentive Plan. General and administrative expenses included $0.9 million and $2.1 million for the three and six months ended June 30, 2017 , respectively, and $1.1 million and $2.4 million for the three and six months ended June 30, 2016 , respectively, of equity-based compensation expense, allocated to the Partnership by Anadarko, for awards granted to the executive officers of the general partner and other employees under the Western Gas Equity Partners, LP 2012 Long-Term Incentive Plan (“WGP LTIP”) and the Anadarko Petroleum Corporation 2012 Omnibus Incentive Compensation Plan (“Anadarko Incentive Plan”). Of this amount, $2.2 million is reflected as contributions to partners’ capital in the Partnership’s consolidated statement of equity and partners’ capital for the six months ended June 30, 2017 . Equipment purchases and sales. The following table summarizes the Partnership’s purchases from and sales to Anadarko of pipe and equipment: Six Months Ended June 30, 2017 2016 2017 2016 thousands Purchases Sales Cash consideration $ 3,910 $ 2,699 $ — $ 613 Net carrying value (4,286 ) (2,328 ) — (596 ) Partners’ capital adjustment $ (376 ) $ 371 $ — $ 17 Contributions in aid of construction costs from affiliates. On certain of the Partnership’s capital projects, Anadarko is obligated to reimburse the Partnership 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 Partnership’s 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 Six Months Ended thousands 2017 2016 2017 2016 Revenues and other (1) $ 316,313 $ 302,405 $ 631,468 $ 574,989 Equity income, net – affiliates (1) 21,728 19,693 41,189 36,507 Cost of product (1) 21,607 22,145 37,595 46,725 Operation and maintenance (2) 18,462 17,661 35,551 35,636 General and administrative (3) 9,365 9,169 18,900 18,121 Operating expenses 49,434 48,975 92,046 100,482 Interest income (4) 4,225 4,225 8,450 8,450 Interest expense (5) — (15,461 ) 71 (10,924 ) Settlement of the Deferred purchase price obligation – Anadarko (6) (37,346 ) — (37,346 ) — Proceeds from the issuance of common units, net of offering expenses (7) — — — 25,000 Distributions to unitholders (8) 110,449 94,909 213,572 184,678 Above-market component of swap agreements with Anadarko 16,373 9,552 28,670 16,365 (1) Represents amounts earned or incurred on and subsequent to the date of the acquisition of Partnership assets, as well as amounts earned or incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets, recognized under gathering, treating or processing agreements, and purchase and sale agreements. (2) Represents expenses incurred on and subsequent to the date of the acquisition of Partnership assets, as well as expenses incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets. (3) Represents general and administrative expense incurred on and subsequent to the date of the Partnership’s acquisition of the Partnership assets, as well as a management services fee for reimbursement of expenses incurred by Anadarko for periods prior to the acquisition of the Partnership assets by the Partnership. These amounts include equity-based compensation expense allocated to the Partnership by Anadarko (see WES LTIP and WGP LTIP and Anadarko Incentive Plan within this Note 5 ). (4) Represents interest income recognized on the note receivable from Anadarko. (5) Includes amounts related to the Deferred purchase price obligation - Anadarko (see Note 2 and Note 9 ). (6) Represents the cash payment to Anadarko for the settlement of the Deferred purchase price obligation - Anadarko (see Note 2 ). (7) Represents proceeds from the issuance of 835,841 common units to WGP as partial funding for the acquisition of Springfield (see Note 2 ). (8) Represents distributions paid under the partnership agreement (see Note 3 and Note 4 ). Concentration of credit risk. Anadarko was the only customer from whom revenues exceeded 10% of the Partnership’s consolidated revenues for all periods presented in the consolidated statements of operations.

Property, Plant and Equipment

Property, Plant and Equipment	6 Months Ended
	Jun. 30, 2017
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	6. PROPERTY, PLANT AND EQUIPMENT A summary of the historical cost of the Partnership’s property, plant and equipment is as follows: thousands Estimated Useful Life June 30, 2017 December 31, 2016 Land n/a $ 4,258 $ 4,012 Gathering systems and processing complexes 3 to 47 years 6,905,758 6,462,053 Pipelines and equipment 15 to 45 years 139,344 139,646 Assets under construction n/a 275,403 226,626 Other 3 to 40 years 30,019 29,605 Total property, plant and equipment 7,354,782 6,861,942 Accumulated depreciation 2,006,988 1,812,010 Net property, plant and equipment $ 5,347,794 $ 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. During the six months ended June 30, 2017 , the Partnership recognized impairments of $167.9 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, the Partnership recognized additional impairments of $9.1 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, (ii) a $3.1 million impairment of the Fort Union equity investment (see Note 7 ) and (iii) the cancellation of a pipeline project in West Texas. During 2016, the Partnership recognized impairments of $15.5 million , including an impairment of $6.1 million at the 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, the Partnership 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	6 Months Ended
	Jun. 30, 2017
Equity Method Investments and Joint Ventures [Abstract]
Equity Investments	7. EQUITY INVESTMENTS The following table presents the activity in the Partnership’s equity investments for the six months ended June 30, 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 1,844 6,701 540 13,388 1,319 8,956 8,441 41,189 Impairment expense (1) (3,110 ) — — — — — — (3,110 ) Contributions — 277 — — — 10 — 287 Distributions (2,239 ) (6,410 ) (1,510 ) (13,407 ) (1,026 ) (9,082 ) (8,528 ) (42,202 ) Distributions in excess of cumulative earnings (2) (800 ) (1,571 ) (1,418 ) (1,717 ) — (2,102 ) (1,613 ) (9,221 ) Balance at June 30, 2017 $ 8,528 $ 46,316 $ 44,351 $ 111,069 $ 16,139 $ 186,976 $ 167,772 $ 581,151 (1) Recorded in Impairments in the consolidated statements of operations. (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. The investment balance in Fort Union at June 30, 2017, is $3.1 million less than the Partnership’s underlying equity in Fort Union’s net assets due to an impairment loss recognized by the Partnership in the second quarter of 2017 for its investment in Fort Union. This investment was impaired to its estimated fair value of $8.5 million , using the income approach and Level 3 fair value inputs.

Components of Working Capital

Components of Working Capital	6 Months Ended
	Jun. 30, 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 June 30, 2017 December 31, 2016 Trade receivables, net $ 136,398 $ 192,808 Other receivables, net 46 30,415 Total accounts receivable, net $ 136,444 $ 223,223 A summary of other current assets is as follows: thousands June 30, 2017 December 31, 2016 Natural gas liquids inventory $ 8,869 $ 7,126 Imbalance receivables 1,020 3,483 Prepaid insurance 272 2,257 Total other current assets $ 10,161 $ 12,866 A summary of accrued liabilities is as follows: thousands June 30, 2017 December 31, 2016 Accrued interest expense $ 40,541 $ 39,826 Short-term asset retirement obligations 6,191 3,114 Short-term remediation and reclamation obligations 630 630 Income taxes payable 1,634 1,006 Other 7,844 532 Total accrued liabilities $ 56,840 $ 45,108

Debt and Interest Expense

Debt and Interest Expense	6 Months Ended
	Jun. 30, 2017
Debt Instruments [Abstract]
Debt and Interest Expense	9. DEBT AND INTEREST EXPENSE At June 30, 2017 , the Partnership’s debt consisted of 5.375% Senior Notes due 2021 (the “2021 Notes”), 4.000% Senior Notes due 2022 (the “2022 Notes”), 2.600% Senior Notes due 2018 (the “2018 Notes”), 5.450% Senior Notes due 2044 (the “2044 Notes”), 3.950% Senior Notes due 2025 (the “2025 Notes”), 4.650% Senior Notes due 2026 (the “2026 Notes”) and borrowings on the RCF. The following table presents the Partnership’s outstanding debt as of June 30, 2017 , and December 31, 2016 : June 30, 2017 December 31, 2016 thousands Principal Carrying Value Fair Value (1) Principal Carrying Value Fair Value (1) 2021 Notes $ 500,000 $ 495,268 $ 537,476 $ 500,000 $ 494,734 $ 536,252 2022 Notes 670,000 668,740 686,001 670,000 668,634 681,723 2018 Notes 350,000 349,434 351,057 350,000 349,188 351,531 2044 Notes 600,000 593,179 618,294 600,000 593,132 615,753 2025 Notes 500,000 491,423 497,615 500,000 490,971 492,499 2026 Notes 500,000 495,021 517,289 500,000 494,802 518,441 RCF 160,000 160,000 160,000 — — — Total long-term debt $ 3,280,000 $ 3,253,065 $ 3,367,732 $ 3,120,000 $ 3,091,461 $ 3,196,199 (1) Fair value is measured using the market approach and Level 2 inputs. Debt activity. The following table presents the debt activity of the Partnership for the six months ended June 30, 2017 : thousands Carrying Value Balance at December 31, 2016 $ 3,091,461 RCF borrowings 160,000 Other 1,604 Balance at June 30, 2017 $ 3,253,065 Senior Notes. At June 30, 2017 , the Partnership was in compliance with all covenants under the indentures governing its outstanding notes. Revolving credit facility. As of June 30, 2017 , the Partnership had $160.0 million of outstanding RCF borrowings and $4.9 million in outstanding letters of credit, resulting in $1.035 billion available for borrowing under the RCF, which matures in February 2020. As of June 30, 2017 and 2016 , the interest rate on the outstanding RCF borrowings was 2.53% and 1.77% , respectively. The facility fee rate was 0.20% at June 30, 2017 and 2016 . At June 30, 2017 , the Partnership was in compliance with all covenants under the RCF. 9. DEBT AND INTEREST EXPENSE (CONTINUED) Interest expense. The following table summarizes the amounts included in interest expense: Three Months Ended Six Months Ended thousands 2017 2016 2017 2016 Third parties Long-term debt $ (35,161 ) $ (28,281 ) $ (69,780 ) $ (56,099 ) Amortization of debt issuance costs and commitment fees (1,645 ) (1,545 ) (3,275 ) (3,075 ) Capitalized interest 1,060 1,482 1,876 3,331 Total interest expense – third parties (35,746 ) (28,344 ) (71,179 ) (55,843 ) Affiliates Deferred purchase price obligation – Anadarko (1) — 15,461 (71 ) 10,924 Total interest expense – affiliates — 15,461 (71 ) 10,924 Interest expense $ (35,746 ) $ (12,883 ) $ (71,250 ) $ (44,919 ) (1) See Note 2 for a discussion of the Deferred purchase price obligation - Anadarko.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. COMMITMENTS AND CONTINGENCIES Litigation and legal proceedings. From time to time, the Partnership is involved in legal, tax, regulatory and other proceedings in various forums regarding performance, contracts and other matters that arise in the ordinary course of business. Management is not aware of any such proceeding the final disposition of which could have a material adverse effect on the Partnership’s financial condition, results of operations or cash flows. Other commitments. The Partnership has short-term payment obligations, or commitments, related to its capital spending programs, as well as those of its unconsolidated affiliates. As of June 30, 2017 , the Partnership had unconditional payment obligations for services to be rendered or products to be delivered in connection with its capital projects of $53.6 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 and (ii) expansion projects at the DBJV system and the DBM and DJ Basin complexes. Lease commitments. Anadarko, on behalf of the Partnership, has entered into lease arrangements for corporate offices, shared field offices and a warehouse supporting the Partnership’s operations, and equipment leases for which Anadarko charges the Partnership rent. The leases for the corporate offices and shared field offices extend through 2028 and 2019, respectively, and the lease for the warehouse expired in February 2017. Rent expense associated with office, warehouse and equipment leases was $11.5 million and $19.4 million for the three and six months ended June 30, 2017 , respectively, and $8.4 million and $17.3 million for the three and six months ended June 30, 2016 , respectively.

Description of Business and B18

Description of Business and Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Consolidation policy	Basis of presentation. The following table outlines the Partnership’s ownership interests and the accounting method of consolidation used in the Partnership’s consolidated financial statements: Percentage Interest Equity investments (1) Fort Union 14.81 % White Cliffs 10 % Rendezvous 22 % Mont Belvieu JV 25 % TEP 20 % TEG 20 % FRP 33.33 % Proportionate consolidation (2) 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 the Partnership exercises significant influence are accounted for under the equity method. “Equity investment throughput” refers to the Partnership’s share of average throughput for these investments. (2) The Partnership proportionately consolidates its associated share of the assets, liabilities, revenues and expenses attributable to these assets. (3) The 25% interest in Chipeta Processing LLC (“Chipeta”) held by a third-party member is reflected within noncontrolling interest in the consolidated financial statements. (4) The Partnership 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 the Partnership and entities in which it holds a controlling financial interest. 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 the Partnership’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.
Business combinations policy	Presentation of Partnership assets. The term “Partnership assets” includes both the assets owned and the interests accounted for under the equity method (see Note 7 ) by the Partnership as of June 30, 2017 . Because Anadarko controls the Partnership through its ownership and control of WGP, which owns the Partnership’s entire general partner interest, each acquisition of Partnership assets from Anadarko has been considered a transfer of net assets between entities under common control. As such, the Partnership assets acquired from Anadarko were initially recorded at Anadarko’s historic carrying value, which did not correlate to the total acquisition price paid by the Partnership. Further, after an acquisition of Partnership assets from Anadarko, the Partnership may be required to recast its financial statements to include the activities of such Partnership assets from the date of common control. 1. DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (CONTINUED) For those periods requiring recast, the consolidated financial statements for periods prior to the Partnership’s acquisition of the Partnership 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 the Partnership had owned the Partnership assets during the periods reported. Net income (loss) attributable to the Partnership assets acquired from Anadarko for periods prior to the Partnership’s acquisition of the Partnership assets is not allocated to the limited partners.
Use of estimates policy	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 Delaware Basin Midstream, LLC (“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. During 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 the Partnership’s estimate of the amount that will be recovered under the property insurance claim based on further discussions with insurers. During the second quarter of 2017, the Partnership reached a settlement with insurers and final proceeds were received. As of June 30, 2017 , and December 31, 2016 , the consolidated balance sheets include receivables of zero and $30.0 million , respectively, for the property insurance claim related to the incident at the DBM complex. During the six months ended June 30, 2017 , the Partnership received $52.9 million in cash proceeds from insurers in final settlement of the Partnership’s claims related to the incident at the DBM complex, including $29.9 million in proceeds from business interruption insurance claims and $23.0 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. The Partnership’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. 1. DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (CONTINUED) 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. The Partnership adopted this ASU on January 1, 2017, using a modified retrospective approach, with no impact to its consolidated financial statements. 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. The Partnership will adopt this ASU on January 1, 2018, and does not expect the adoption to have a material impact 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. The Partnership will adopt this ASU on January 1, 2018, and does not expect the adoption 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, and a modified retrospective approach is required for all comparative periods presented. The Partnership plans to elect certain practical expedients when implementing the new lease standard, which means the Partnership will not have to reassess the accounting for contracts that commenced prior to adoption . The Partnership is continuing to analyze its portfolio of contracts to assess the application of this ASU to certain types of contracts, its current business processes and the impact that adoption will 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. The Partnership 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. The Partnership 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. The Partnership 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. The Partnership will adopt this 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 unit for common units. Net income (loss) attributable to the Partnership assets acquired from Anadarko for periods prior to the Partnership’s acquisition of the Partnership assets is not allocated to the unitholders for purposes of calculating net income (loss) per common unit. Net income (loss) attributable to Western Gas Partners, LP earned on and subsequent to the date of acquisition of the Partnership assets is allocated as follows: General partner. The general partner’s allocation is equal to cash distributions plus its portion of undistributed earnings or losses. Specifically, net income equal to the amount of available cash (as defined by the partnership agreement) is allocated to the general partner consistent with actual cash distributions and capital account allocations, including incentive distributions. Undistributed earnings (net income in excess of distributions) or undistributed losses (available cash in excess of net income) are then allocated to the general partner in accordance with its weighted-average ownership percentage during each period. Series A Preferred unitholders. The Series A Preferred units were not considered a participating security as they only had distribution rights up to the specified per-unit quarterly distribution and had no rights to the Partnership’s undistributed earnings and losses. As such, the Series A Preferred unitholders’ allocation was equal to their cash distribution plus the amortization of the Series A Preferred units beneficial conversion feature (see Series A Preferred units above). Common and Class C unitholders. The Class C units are considered a participating security because they participate in distributions with common units according to a predetermined formula (see Note 3 ). The common and Class C unitholders’ allocation is equal to their cash distributions plus their respective portions of undistributed earnings or losses. Specifically, net income equal to the amount of available cash (as defined by the partnership agreement) is allocated to the common and Class C unitholders consistent with actual cash distributions and capital account allocations. Undistributed earnings or undistributed losses are then allocated to the common and Class C unitholders in accordance with their respective weighted-average ownership percentages during each period. The common unitholder allocation also includes the impact of the amortization of the Series A Preferred units and Class C units beneficial conversion features. The Class C unitholder allocation is similarly impacted by the amortization of the Class C units beneficial conversion feature (see Class C units above). Calculation of net income (loss) per unit. Basic net income (loss) per common unit is calculated by dividing the net income (loss) attributable to common unitholders by the weighted-average number of common units outstanding during the period. The common units issued in connection with acquisitions and equity offerings are included on a weighted-average basis for periods they were outstanding. Diluted net income (loss) per common unit is calculated by dividing the sum of (i) the net income (loss) attributable to common units adjusted for distributions on the Series A Preferred units and a reallocation of the common and Class C limited partners’ interest in net income (loss) assuming conversion of the Series A Preferred units into common units, and (ii) the net income (loss) attributable to the Class C units as a participating security, by the sum of the weighted-average number of common units outstanding plus the dilutive effect of (i) the weighted-average number of outstanding Class C units and (ii) the weighted-average number of common units outstanding assuming conversion of the Series A Preferred units.

Description of Business and B19

Description of Business and Basis of Presentation (Tables)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Assets and Investments Table	As of June 30, 2017 , the Partnership’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 19 3 — 3 Natural gas processing plants/trains 19 5 — 2 NGL pipelines 2 — — 3 Natural gas pipelines 5 — — — Oil pipelines — 1 — 1
Ownership Interest and Method of Consolidation Table	The following table outlines the Partnership’s ownership interests and the accounting method of consolidation used in the Partnership’s consolidated financial statements: Percentage Interest Equity investments (1) Fort Union 14.81 % White Cliffs 10 % Rendezvous 22 % Mont Belvieu JV 25 % TEP 20 % TEG 20 % FRP 33.33 % Proportionate consolidation (2) 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 the Partnership exercises significant influence are accounted for under the equity method. “Equity investment throughput” refers to the Partnership’s share of average throughput for these investments. (2) The Partnership proportionately consolidates its associated share of the assets, liabilities, revenues and expenses attributable to these assets. (3) The 25% interest in Chipeta Processing LLC (“Chipeta”) held by a third-party member is reflected within noncontrolling interest in the consolidated financial statements. (4) The Partnership 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)	6 Months Ended
	Jun. 30, 2017
Property, Plant and Equipment [Abstract]
Acquisitions Table	The following table presents the acquisitions completed by the Partnership 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 Common Units Issued 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) The Partnership acquired Springfield Pipeline LLC (“Springfield”) from Anadarko for $750.0 million , consisting of $712.5 million in cash and the issuance of 1,253,761 of the Partnership’s common units. Springfield owns a 50.1% interest in an oil gathering system and a gas gathering system, such interest being referred to in this report as the “Springfield interest.” The Springfield oil and gas gathering systems (collectively, the “Springfield system”) are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. The Partnership financed the cash portion of the acquisition through: (i) borrowings of $247.5 million on the Partnership’s senior unsecured revolving credit facility (“RCF”), (ii) the issuance of 835,841 of the Partnership’s common units to WGP and (iii) the issuance of Series A Preferred units to private investors. See Note 4 for further information regarding the Series A Preferred units. (2) The Partnership 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 Settlement of the Deferred purchase price obligation – Anadarko (37,346 ) Balance at June 30, 2017 $ — $ — (1) Calculated using Level 3 inputs. (2) Accretion expense was recorded as a charge to Interest expense in the consolidated statements of operations. (3) Recorded as revisions within Common units in the consolidated balance sheet and consolidated statement of equity and partners’ capital.

Partnership Distributions (Tabl

Partnership Distributions (Tables)	6 Months Ended
	Jun. 30, 2017
Distribution Made to Limited Partner [Line Items]
Cash Distributions Table	The Board of Directors of the Partnership’s general partner (the “Board of Directors”) declared the following cash distributions to the Partnership’s common and general partner unitholders for the periods presented: thousands except per-unit amounts Quarters Ended Total Quarterly Distribution per Unit Total Quarterly Cash Distribution Date of Distribution 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 $ 0.875 $ 188,753 May 2017 June 30 (1) 0.890 207,491 August 2017 (1) The Board of Directors declared a cash distribution to the Partnership’s unitholders for the second quarter of 2017 of $0.890 per unit, or $207.5 million in aggregate, including incentive distributions, but excluding distributions on Class C units (see Class C unit distributions below). The cash distribution is payable on August 11, 2017 , to unitholders of record at the close of business on July 31, 2017 .
Series A Preferred Units [Member]
Distribution Made to Limited Partner [Line Items]
Cash Distributions Table	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 $ 0.68 $ 7,453 May 2017 (1) Quarterly per unit distribution prorated for the 18 -day period during which 14,030,611 Series A Preferred units were outstanding during the first quarter of 2016. (2) Full quarterly per unit distribution on 14,030,611 Series A Preferred units and quarterly per unit distribution prorated for the 77 -day period during which 7,892,220 Series A Preferred units were outstanding during the second quarter of 2016.

Equity and Partners' Capital (T

Equity and Partners' Capital (Tables)	6 Months Ended
	Jun. 30, 2017
Partners' Capital Notes [Abstract]
Partnership Interests Table	The following table summarizes the common, Class C, Series A Preferred and general partner units issued during the six months ended June 30, 2017 : Common Units Class C Units Series A Preferred Units 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 — 385,195 — — 385,195 Conversion of Series A Preferred units 21,922,831 — (21,922,831 ) — — Long-Term Incentive Plan award vestings 7,304 — — — 7,304 Balance at June 30, 2017 152,602,105 12,743,318 — 2,583,068 167,928,491
Calculation of Net Income (Loss) Per Unit Table	The following table illustrates the Partnership’s calculation of net income (loss) per unit for common units: Three Months Ended Six Months Ended thousands except per-unit amounts 2017 2016 2017 2016 Net income (loss) attributable to Western Gas Partners, LP $ 173,451 $ 164,521 $ 275,340 $ 280,581 Pre-acquisition net (income) loss allocated to Anadarko — — — (11,326 ) Series A Preferred units interest in net (income) loss (1) (14,199 ) (23,121 ) (42,373 ) (25,450 ) General partner interest in net (income) loss (76,365 ) (58,381 ) (144,527 ) (113,781 ) Common and Class C limited partners’ interest in net income (loss) $ 82,887 $ 83,019 $ 88,440 $ 130,024 Net income (loss) allocable to common units (1) $ 73,383 $ 71,622 $ 75,097 $ 111,184 Net income (loss) allocable to Class C units (1) 9,504 11,397 13,343 18,840 Common and Class C limited partners’ interest in net income (loss) $ 82,887 $ 83,019 $ 88,440 $ 130,024 Net income (loss) per unit Common units – basic and diluted (2) $ 0.49 $ 0.55 $ 0.53 $ 0.86 Weighted-average units outstanding Common units – basic and diluted 148,864 130,669 141,696 129,830 Excluded due to anti-dilutive effect: Class C units (2) 12,650 11,849 12,552 11,719 Series A Preferred units assuming conversion to common units (2) 3,734 20,709 10,901 11,742 (1) Adjusted to reflect amortization of the beneficial conversion features. (2) The impact of Class C units and the conversion of Series A Preferred units would be anti-dilutive for all periods presented. As of May 2, 2017, all Series A Preferred units were converted into common units on a one -for-one basis.

Transactions with Affiliates (T

Transactions with Affiliates (Tables)	6 Months Ended
	Jun. 30, 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 Six Months Ended thousands 2017 2016 2017 2016 Gains (losses) on commodity price swap agreements related to sales: (1) Natural gas sales $ 4,656 $ 5,202 $ 5,738 $ 12,243 Natural gas liquids sales 1,837 20,480 (2,470 ) 40,550 Total 6,493 25,682 3,268 52,793 Gains (losses) on commodity price swap agreements related to purchases (2) (5,507 ) (16,913 ) (2,811 ) (35,784 ) Net gains (losses) on commodity price swap agreements $ 986 $ 8,769 $ 457 $ 17,009 (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 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 the Partnership’s purchases from Anadarko of pipe and equipment: Six Months Ended June 30, 2017 2016 2017 2016 thousands Purchases Sales Cash consideration $ 3,910 $ 2,699 $ — $ 613 Net carrying value (4,286 ) (2,328 ) — (596 ) Partners’ capital adjustment $ (376 ) $ 371 $ — $ 17 The following table summarizes material affiliate transactions. See Note 2 for discussion of affiliate acquisitions and related funding. Three Months Ended Six Months Ended thousands 2017 2016 2017 2016 Revenues and other (1) $ 316,313 $ 302,405 $ 631,468 $ 574,989 Equity income, net – affiliates (1) 21,728 19,693 41,189 36,507 Cost of product (1) 21,607 22,145 37,595 46,725 Operation and maintenance (2) 18,462 17,661 35,551 35,636 General and administrative (3) 9,365 9,169 18,900 18,121 Operating expenses 49,434 48,975 92,046 100,482 Interest income (4) 4,225 4,225 8,450 8,450 Interest expense (5) — (15,461 ) 71 (10,924 ) Settlement of the Deferred purchase price obligation – Anadarko (6) (37,346 ) — (37,346 ) — Proceeds from the issuance of common units, net of offering expenses (7) — — — 25,000 Distributions to unitholders (8) 110,449 94,909 213,572 184,678 Above-market component of swap agreements with Anadarko 16,373 9,552 28,670 16,365 (1) Represents amounts earned or incurred on and subsequent to the date of the acquisition of Partnership assets, as well as amounts earned or incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets, recognized under gathering, treating or processing agreements, and purchase and sale agreements. (2) Represents expenses incurred on and subsequent to the date of the acquisition of Partnership assets, as well as expenses incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets. (3) Represents general and administrative expense incurred on and subsequent to the date of the Partnership’s acquisition of the Partnership assets, as well as a management services fee for reimbursement of expenses incurred by Anadarko for periods prior to the acquisition of the Partnership assets by the Partnership. These amounts include equity-based compensation expense allocated to the Partnership by Anadarko (see WES LTIP and WGP LTIP and Anadarko Incentive Plan within this Note 5 ). (4) Represents interest income recognized on the note receivable from Anadarko. (5) Includes amounts related to the Deferred purchase price obligation - Anadarko (see Note 2 and Note 9 ). (6) Represents the cash payment to Anadarko for the settlement of the Deferred purchase price obligation - Anadarko (see Note 2 ). (7) Represents proceeds from the issuance of 835,841 common units to WGP as partial funding for the acquisition of Springfield (see Note 2 ). (8) Represents distributions paid under the partnership agreement (see Note 3 and Note 4 ).

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	6 Months Ended
	Jun. 30, 2017
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment Table	A summary of the historical cost of the Partnership’s property, plant and equipment is as follows: thousands Estimated Useful Life June 30, 2017 December 31, 2016 Land n/a $ 4,258 $ 4,012 Gathering systems and processing complexes 3 to 47 years 6,905,758 6,462,053 Pipelines and equipment 15 to 45 years 139,344 139,646 Assets under construction n/a 275,403 226,626 Other 3 to 40 years 30,019 29,605 Total property, plant and equipment 7,354,782 6,861,942 Accumulated depreciation 2,006,988 1,812,010 Net property, plant and equipment $ 5,347,794 $ 5,049,932

Equity Investments (Tables)

Equity Investments (Tables)	6 Months Ended
	Jun. 30, 2017
Equity Method Investments and Joint Ventures [Abstract]
Equity Investments Table	The following table presents the activity in the Partnership’s equity investments for the six months ended June 30, 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 1,844 6,701 540 13,388 1,319 8,956 8,441 41,189 Impairment expense (1) (3,110 ) — — — — — — (3,110 ) Contributions — 277 — — — 10 — 287 Distributions (2,239 ) (6,410 ) (1,510 ) (13,407 ) (1,026 ) (9,082 ) (8,528 ) (42,202 ) Distributions in excess of cumulative earnings (2) (800 ) (1,571 ) (1,418 ) (1,717 ) — (2,102 ) (1,613 ) (9,221 ) Balance at June 30, 2017 $ 8,528 $ 46,316 $ 44,351 $ 111,069 $ 16,139 $ 186,976 $ 167,772 $ 581,151 (1) Recorded in Impairments in the consolidated statements of operations. (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 (Tables)	6 Months Ended
	Jun. 30, 2017
Components Of Working Capital [Abstract]
Accounts Receivable, Net Table	A summary of accounts receivable, net is as follows: thousands June 30, 2017 December 31, 2016 Trade receivables, net $ 136,398 $ 192,808 Other receivables, net 46 30,415 Total accounts receivable, net $ 136,444 $ 223,223
Other Current Assets Table	A summary of other current assets is as follows: thousands June 30, 2017 December 31, 2016 Natural gas liquids inventory $ 8,869 $ 7,126 Imbalance receivables 1,020 3,483 Prepaid insurance 272 2,257 Total other current assets $ 10,161 $ 12,866
Accrued Liabilities Table	A summary of accrued liabilities is as follows: thousands June 30, 2017 December 31, 2016 Accrued interest expense $ 40,541 $ 39,826 Short-term asset retirement obligations 6,191 3,114 Short-term remediation and reclamation obligations 630 630 Income taxes payable 1,634 1,006 Other 7,844 532 Total accrued liabilities $ 56,840 $ 45,108

Debt and Interest Expense (Tabl

Debt and Interest Expense (Tables)	6 Months Ended
	Jun. 30, 2017
Debt Instruments [Abstract]
Debt Outstanding and Debt Activity Tables	The following table presents the Partnership’s outstanding debt as of June 30, 2017 , and December 31, 2016 : June 30, 2017 December 31, 2016 thousands Principal Carrying Value Fair Value (1) Principal Carrying Value Fair Value (1) 2021 Notes $ 500,000 $ 495,268 $ 537,476 $ 500,000 $ 494,734 $ 536,252 2022 Notes 670,000 668,740 686,001 670,000 668,634 681,723 2018 Notes 350,000 349,434 351,057 350,000 349,188 351,531 2044 Notes 600,000 593,179 618,294 600,000 593,132 615,753 2025 Notes 500,000 491,423 497,615 500,000 490,971 492,499 2026 Notes 500,000 495,021 517,289 500,000 494,802 518,441 RCF 160,000 160,000 160,000 — — — Total long-term debt $ 3,280,000 $ 3,253,065 $ 3,367,732 $ 3,120,000 $ 3,091,461 $ 3,196,199 (1) Fair value is measured using the market approach and Level 2 inputs. Debt activity. The following table presents the debt activity of the Partnership for the six months ended June 30, 2017 : thousands Carrying Value Balance at December 31, 2016 $ 3,091,461 RCF borrowings 160,000 Other 1,604 Balance at June 30, 2017 $ 3,253,065
Interest Expense Table	The following table summarizes the amounts included in interest expense: Three Months Ended Six Months Ended thousands 2017 2016 2017 2016 Third parties Long-term debt $ (35,161 ) $ (28,281 ) $ (69,780 ) $ (56,099 ) Amortization of debt issuance costs and commitment fees (1,645 ) (1,545 ) (3,275 ) (3,075 ) Capitalized interest 1,060 1,482 1,876 3,331 Total interest expense – third parties (35,746 ) (28,344 ) (71,179 ) (55,843 ) Affiliates Deferred purchase price obligation – Anadarko (1) — 15,461 (71 ) 10,924 Total interest expense – affiliates — 15,461 (71 ) 10,924 Interest expense $ (35,746 ) $ (12,883 ) $ (71,250 ) $ (44,919 ) (1) See Note 2 for a discussion of the Deferred purchase price obligation - Anadarko.

Description of Business and B28

Description of Business and Basis of Presentation - Assets and Investments Table (Details)	Jun. 30, 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	19
Owned and Operated [Member] | Natural Gas Processing Plants/Trains [Member]
Assets [Line Items]
Assets, number of units	19
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 B29

Description of Business and Basis of Presentation - Ownership Interest and Method of Consolidation Table (Details)		Mar. 17, 2017	Jun. 30, 2017
Chipeta [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership interest by noncontrolling interest owner			25.00%
DBJV System [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership percentage acquired	[1]	50.00%
Equity Investments [Member] | Fort Union [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[2]		14.81%
Equity Investments [Member] | White Cliffs [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[2]		10.00%
Equity Investments [Member] | Rendezvous [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[2]		22.00%
Equity Investments [Member] | Mont Belvieu JV [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[2]		25.00%
Equity Investments [Member] | Texas Express Pipeline LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[2]		20.00%
Equity Investments [Member] | Texas Express Gathering LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[2]		20.00%
Equity Investments [Member] | Front Range Pipeline LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[2]		33.33%
Proportionate Consolidation [Member] | Marcellus Interest Systems [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[3]		33.75%
Proportionate Consolidation [Member] | Newcastle System [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[3]		50.00%
Proportionate Consolidation [Member] | Springfield System [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[3]		50.10%
Full Consolidation [Member] | Chipeta [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[4]		75.00%
Full Consolidation [Member] | DBJV System [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage ownership interest	[5]		100.00%
[1]	The Partnership acquired the Additional DBJV System Interest from a third party. See Property exchange below.
[2]	Investments in non-controlled entities over which the Partnership exercises significant influence are accounted for under the equity method. “Equity investment throughput” refers to the Partnership’s share of average throughput for these investments.
[3]	The Partnership proportionately consolidates its 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 interest in the consolidated financial statements.
[5]	The Partnership 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 B30

Description of Business and Basis of Presentation - Additional Information (Details) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)Mcf / d	Jun. 30, 2016USD ($)	Dec. 31, 2016USD ($)
Loss on divestiture and other, net	$ (15,458)		$ 1,907	$ (134,945)	$ 2,539
Proceeds from property insurance claims				22,977	$ 2,944
Delaware Basin Midstream Complex [Member]
Loss on divestiture and other, net		$ 5,700
Property insurance claim receivable	$ 0			0		$ 30,000
Proceeds from insurance claims, total				52,900
Proceeds from business interruption insurance claims				29,882
Proceeds from property insurance claims				$ 22,977
Delaware Basin Midstream Complex [Member] | Train II [Member]
Plant capacity | Mcf / d				100,000
Delaware Basin Midstream Complex [Member] | Train III [Member]
Plant capacity | Mcf / d				200,000

Acquisitions and Divestitures -

Acquisitions and Divestitures - Acquisitions Table (Details) - USD ($) $ in Thousands		Mar. 17, 2017	Mar. 14, 2016	Jun. 30, 2017
Business Acquisition [Line Items]
Units issued				385,195
Revolving Credit Facility [Member]
Business Acquisition [Line Items]
Borrowings - revolving credit facility				$ 160,000
Springfield [Member]
Business Acquisition [Line Items]
Ownership percentage acquired	[1]		50.10%
Acquisition price			$ 750,000
Cash payment for acquisition			$ 712,500
Springfield [Member] | Common Units [Member]
Business Acquisition [Line Items]
Units issued	[1]		2,089,602
Springfield [Member] | Common Units [Member] | Anadarko [Member]
Business Acquisition [Line Items]
Units issued			1,253,761
Springfield [Member] | Common Units [Member] | Western Gas Equity Partners, LP [Member]
Business Acquisition [Line Items]
Units issued			835,841
Springfield [Member] | Series A Preferred Units [Member]
Business Acquisition [Line Items]
Units issued	[1]		14,030,611
Springfield [Member] | Revolving Credit Facility [Member]
Business Acquisition [Line Items]
Borrowings - revolving credit facility	[1]		$ 247,500
Delaware Basin JV Gathering LLC [Member]
Business Acquisition [Line Items]
Ownership percentage acquired	[2]	50.00%
Cash on hand	[2]	$ 155,000
[1]	The Partnership acquired Springfield Pipeline LLC (“Springfield”) from Anadarko for $750.0 million, consisting of $712.5 million in cash and the issuance of 1,253,761 of the Partnership’s common units. Springfield owns a 50.1% interest in an oil gathering system and a gas gathering system, such interest being referred to in this report as the “Springfield interest.” The Springfield oil and gas gathering systems (collectively, the “Springfield system”) are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. The Partnership financed the cash portion of the acquisition through: (i) borrowings of $247.5 million on the Partnership’s senior unsecured revolving credit facility (“RCF”), (ii) the issuance of 835,841 of the Partnership’s common units to WGP and (iii) the issuance of Series A Preferred units to private investors. See Note 4 for further information regarding the Series A Preferred units.
[2]	The Partnership acquired the Additional DBJV System Interest from a third party. See Property exchange below.

Acquisitions and Divestitures32

Acquisitions and Divestitures - Impact of the Deferred Purchase Price Obligation - Anadarko Table (Details) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Deferred purchase price obligation - Anadarko, present value	[1]	$ 0			$ 0		$ 41,440
Affiliates [Member]
Property, Plant and Equipment [Line Items]
Settlement of the Deferred purchase price obligation - Anadarko	[2]				(37,346)	$ 0
Affiliates [Member] | Deferred Purchase Price Obligation - Anadarko [Member]
Property, Plant and Equipment [Line Items]
Accretion expense	[3]	0		$ (15,461)	71	(10,924)
Settlement of the Deferred purchase price obligation - Anadarko	[4]	(37,346)		$ 0	(37,346)	$ 0
Affiliates [Member] | Delaware Basin JV Gathering LLC [Member] | Deferred Purchase Price Obligation - Anadarko [Member]
Property, Plant and Equipment [Line Items]
Deferred purchase price obligation - Anadarko, present value		0	$ 37,346		0		41,440
Accretion expense	[5]		71
Revision to Deferred purchase price obligation – Anadarko	[6]		(4,165)
Settlement of the Deferred purchase price obligation - Anadarko		(37,346)
Deferred purchase price obligation - Anadarko, future value	[7]	$ 0	$ 49,694		$ 0		$ 56,455
[1]	See Note 2.
[2]	See Note 2.
[3]	See Note 2 for a discussion of the Deferred purchase price obligation - Anadarko.
[4]	Represents the cash payment to Anadarko for the settlement of the Deferred purchase price obligation - Anadarko (see Note 2).
[5]	Accretion expense was recorded as a charge to Interest expense in the consolidated statements of operations.
[6]	Recorded as revisions within Common units in the consolidated balance sheet and consolidated statement of equity and partners’ capital.
[7]	Calculated using Level 3 inputs.

Acquisitions and Divestitures33

Acquisitions and Divestitures - Additional Information (Details) - USD ($) $ in Thousands		Mar. 17, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Helper and Clawson Systems [Member]
Property, Plant and Equipment [Line Items]
Gain (loss) on sale of assets			$ 16,300
Hugoton System [Member]
Property, Plant and Equipment [Line Items]
Gain (loss) on sale of assets							$ (12,000)
Goodwill allocated to divestiture							$ 1,600
Affiliates [Member]
Property, Plant and Equipment [Line Items]
Cash payment					$ 3,910	$ 715,199
Settlement of the Deferred purchase price obligation - Anadarko	[1]				37,346	0
Deferred Purchase Price Obligation - Anadarko [Member] | Affiliates [Member]
Property, Plant and Equipment [Line Items]
Settlement of the Deferred purchase price obligation - Anadarko	[2]		37,346	$ 0	37,346	$ 0
Delaware Basin JV Gathering LLC [Member]
Property, Plant and Equipment [Line Items]
Percentage ownership interest		50.00%
Cash payment	[3]	$ 155,000
Net gain from property exchange					$ 125,700
Delaware Basin JV Gathering LLC [Member] | Deferred Purchase Price Obligation - Anadarko [Member] | Affiliates [Member]
Property, Plant and Equipment [Line Items]
Settlement of the Deferred purchase price obligation - Anadarko			$ 37,346
Non-Operated Marcellus Interest [Member]
Property, Plant and Equipment [Line Items]
Percentage ownership interest		33.75%
[1]	See Note 2.
[2]	Represents the cash payment to Anadarko for the settlement of the Deferred purchase price obligation - Anadarko (see Note 2).
[3]	The Partnership acquired the Additional DBJV System Interest from a third party. See Property exchange below.

Partnership Distributions - Cas

Partnership Distributions - Cash Distributions Table (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Jun. 30, 2017	[1]	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016
Distributions Made to Members or Limited Partners [Abstract]
Total quarterly distribution per unit	$ 0.890		$ 0.875	$ 0.860	$ 0.845	$ 0.830	$ 0.815
Total quarterly cash distribution	$ 207,491		$ 188,753	$ 170,657	$ 166,742	$ 162,827	$ 158,905
[1]	The Board of Directors declared a cash distribution to the Partnership’s unitholders for the second quarter of 2017 of $0.890 per unit, or $207.5 million in aggregate, including incentive distributions, but excluding distributions on Class C units (see Class C unit distributions below). The cash distribution is payable on August 11, 2017, to unitholders of record at the close of business on July 31, 2017.

Partnership Distributions - Ser

Partnership Distributions - Series A Preferred Unit Distributions Table (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended							6 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016		Mar. 31, 2016		Jun. 30, 2017	Dec. 31, 2016
Distribution Made to Limited Partner [Line Items]
Units issued								385,195
Series A Preferred Units [Member]
Distribution Made to Limited Partner [Line Items]
Series A Preferred units quarterly distribution per unit	$ 0.68	$ 0.68	$ 0.68	$ 0.68	[1]	$ 0.68	[2]	$ 0.68
Series A Preferred units quarterly cash distribution	$ 7,453	$ 14,908	$ 14,908	$ 14,082	[1]	$ 1,887	[2]
Number of days in prorated period				77 days		18 days
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]	Full quarterly per unit distribution on 14,030,611 Series A Preferred units and quarterly per unit distribution prorated for the 77-day period during which 7,892,220 Series A Preferred units were outstanding during the second quarter of 2016.
[2]	Quarterly per unit distribution prorated for the 18-day period during which 14,030,611 Series A Preferred units were outstanding during the first quarter of 2016.

Partnership Distributions - Add

Partnership Distributions - Additional Information (Details) - $ / shares	May 02, 2017	Mar. 01, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	[1]	Mar. 31, 2016	[2]	Jun. 30, 2017
Distribution Made to Limited Partner [Line Items]
Partnership agreement day requirement of distribution of available cash										45 days
Incentive distributions percentage										48.00%
Minimum [Member]
Distribution Made to Limited Partner [Line Items]
Distribution sharing percentage										1.50%
Maximum [Member]
Distribution Made to Limited Partner [Line Items]
Distribution sharing percentage										49.50%
Class C Units [Member]
Distribution Made to Limited Partner [Line Items]
Discount rate percentage										6.00%
Series A Preferred Units [Member]
Distribution Made to Limited Partner [Line Items]
Series A Preferred units quarterly distribution per unit			$ 0.68	$ 0.68	$ 0.68	$ 0.68		$ 0.68		$ 0.68
Series A Preferred units, common units issued upon conversion										1
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, common units issued upon conversion		1
Series A Preferred Units [Member] | Series A Preferred Units May 2017 Conversion [Member]
Distribution Made to Limited Partner [Line Items]
Series A Preferred units, percentage converted	50.00%
Series A Preferred units, common units issued upon conversion	1
[1]	Full quarterly per unit distribution on 14,030,611 Series A Preferred units and quarterly per unit distribution prorated for the 77-day period during which 7,892,220 Series A Preferred units were outstanding during the second quarter of 2016.
[2]	Quarterly per unit distribution prorated for the 18-day period during which 14,030,611 Series A Preferred units were outstanding during the first quarter of 2016.

Equity and Partners' Capital -

Equity and Partners' Capital - Partnership Interests Table (Details)	6 Months Ended
	Jun. 30, 2017shares
Capital Unit [Line Items]
Balance	167,535,992
Units issued	385,195
Conversion of Series A Preferred units	0
Long-Term Incentive Plan award vestings	7,304
Balance	167,928,491
Common Units [Member]
Capital Unit [Line Items]
Balance	130,671,970
Conversion of Series A Preferred units	21,922,831
Long-Term Incentive Plan award vestings	7,304
Balance	152,602,105
Class C Units [Member]
Capital Unit [Line Items]
Balance	12,358,123
Units issued	385,195
Balance	12,743,318
Series A Preferred Units [Member]
Capital Unit [Line Items]
Balance	21,922,831
Conversion of Series A Preferred units	(21,922,831)
Balance	0
General Partner [Member]
Capital Unit [Line Items]
Balance	2,583,068
Balance	2,583,068

Equity and Partners' Capital 38

Equity and Partners' Capital - Calculation of Net Income (Loss) Per Unit Table (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Unit [Line Items]
Net income (loss) attributable to Western Gas Partners, LP		$ 173,451	$ 164,521	$ 275,340	$ 280,581
Pre-acquisition net (income) loss allocated to Anadarko		0	0	0	(11,326)
General partner interest in net (income) loss	[1]	$ (76,365)	$ (58,381)	$ (144,527)	$ (113,781)
Net income (loss) per common unit – basic and diluted	[2],[3]	$ 0.49	$ 0.55	$ 0.53	$ 0.86
Series A Preferred Units [Member]
Earnings Per Unit [Line Items]
Limited partners’ interest in net income (loss)	[4]	$ 14,199	$ 23,121	$ 42,373	$ 25,450
Anti-dilutive units excluded from computation of earnings per unit	[3]	3,734,000	20,709,000	10,901,000	11,742,000
Series A Preferred units, common units issued upon conversion		1		1
Common and Class C Units [Member]
Earnings Per Unit [Line Items]
Limited partners’ interest in net income (loss)	[1]	$ 82,887	$ 83,019	$ 88,440	$ 130,024
Common Units [Member]
Earnings Per Unit [Line Items]
Limited partners’ interest in net income (loss)	[4]	$ 73,383	$ 71,622	$ 75,097	$ 111,184
Weighted-average units outstanding - basic and diluted		148,864,000	130,669,000	141,696,000	129,830,000
Class C Units [Member]
Earnings Per Unit [Line Items]
Limited partners’ interest in net income (loss)	[4]	$ 9,504	$ 11,397	$ 13,343	$ 18,840
Anti-dilutive units excluded from computation of earnings per unit	[3]	12,650,000	11,849,000	12,552,000	11,719,000
[1]	Represents net income (loss) earned on and subsequent to the date of acquisition of the Partnership assets (as defined in Note 1). See Note 4.
[2]	See Note 4 for the calculation of net income (loss) per common unit.
[3]	The impact of Class C units and the conversion of Series A Preferred units would be anti-dilutive for all periods presented. As of May 2, 2017, all Series A Preferred units were converted into common units on a one-for-one basis.
[4]	Adjusted to reflect amortization of the beneficial conversion features.

Equity and Partners' Capital 39

Equity and Partners' Capital - Additional Information (Details) - USD ($) $ in Thousands	May 02, 2017	Mar. 01, 2017	Nov. 30, 2014	Mar. 31, 2016	Jun. 30, 2017	Dec. 31, 2016	Dec. 31, 2014
Schedule Of Investments [Line Items]
Units issued					385,195
Amortization of beneficial conversion feature of Series A Preferred units					$ 0
General partner units owned					2,583,068	2,583,068
Western Gas Equity Partners, LP [Member] | Western Gas Partners, LP [Member]
Schedule Of Investments [Line Items]
General partner units owned					2,583,068
General partner's interest					1.50%
Common Units [Member]
Schedule Of Investments [Line Items]
Limited partner units owned					152,602,105	130,671,970
Common Units [Member] | Western Gas Partners, LP [Member] | Public [Member]
Schedule Of Investments [Line Items]
Limited partner units owned					100,458,679
Limited partner ownership interest					59.80%
Common Units [Member] | Western Gas Equity Partners, LP [Member] | Western Gas Partners, LP [Member]
Schedule Of Investments [Line Items]
Limited partner units owned					50,132,046
Limited partner ownership interest					29.90%
Common Units [Member] | Other Subsidiaries Of Anadarko [Member] | Western Gas Partners, LP [Member]
Schedule Of Investments [Line Items]
Limited partner units owned					2,011,380
Class C Units [Member]
Schedule Of Investments [Line Items]
Units issued					385,195
Class C units, common units issued upon conversion					1
Beneficial conversion feature							$ 34,800
Limited partner units owned					12,743,318	12,358,123
Class C Units [Member] | Other Subsidiaries Of Anadarko [Member] | Western Gas Partners, LP [Member]
Schedule Of Investments [Line Items]
Limited partner units owned					12,743,318
Class C Units [Member] | Other Subsidiaries Of Anadarko [Member]
Schedule Of Investments [Line Items]
Units issued			10,913,853
Series A Preferred Units [Member]
Schedule Of Investments [Line Items]
Beneficial conversion feature						$ 93,400
Series A Preferred units, common units issued upon conversion					1
Amortization of beneficial conversion feature of Series A Preferred units					$ 62,299
Limited partner units owned					0	21,922,831
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, common units issued upon conversion		1
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%
Series A Preferred units, common units issued upon conversion	1
Series A Preferred Units [Member] | Private Investor [Member]
Schedule Of Investments [Line Items]
Units issued				14,030,611		21,922,831
Incentive Distribution Rights [Member] | Western Gas Equity Partners, LP [Member] | Western Gas Partners, LP [Member]
Schedule Of Investments [Line Items]
General partner's interest					100.00%
Common and Class C Units [Member] | Other Subsidiaries Of Anadarko [Member] | Western Gas Partners, LP [Member]
Schedule Of Investments [Line Items]
Limited partner ownership interest					8.80%

Transactions with Affiliates -

Transactions with Affiliates - Gains (Losses) on Commodity Price Swap Agreements Table (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements		$ 986	$ 8,769	$ 457	$ 17,009
Sales [Member]
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements	[1]	6,493	25,682	3,268	52,793
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]	4,656	5,202	5,738	12,243
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]	1,837	20,480	(2,470)	40,550
Purchases [Member]
Gains (losses) on commodity price swap agreements related to sales and purchases
Gains (losses) on commodity price swap agreements	[2]	$ (5,507)	$ (16,913)	$ (2,811)	$ (35,784)
[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 Tables (Details)		Jun. 30, 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 and Sales Table (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Related Party Transaction [Line Items]
Partners’ capital adjustment	$ (376)	$ 354
Affiliates [Member] | Purchases [Member]
Related Party Transaction [Line Items]
Cash consideration - purchases	3,910	2,699
Net carrying value	(4,286)	(2,328)
Partners’ capital adjustment	(376)	371
Affiliates [Member] | Sales [Member]
Related Party Transaction [Line Items]
Cash consideration - sales	0	613
Net carrying value	0	(596)
Partners’ capital adjustment	$ 0	$ (17)

Transactions with Affiliates 43

Transactions with Affiliates - Summary of Affiliate Transactions Table (Details) - USD ($) $ in Thousands		Mar. 14, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017		Jun. 30, 2016
Related Party Transaction [Line Items]
Revenues and other			$ 525,450	$ 428,664	$ 1,041,643		$ 811,805
Equity income, net – affiliates	[1]		21,728	19,693	41,189		36,507
Cost of product	[2]		203,277	104,849	392,636		181,316
Operation and maintenance	[2]		76,148	75,173	149,908		151,386
General and administrative	[2]		10,585	10,883	23,244		22,160
Operating expenses			379,143	272,691	901,659		518,611
Interest income	[3]		4,225	4,225	8,450		8,450
Interest expense	[4]		35,746	12,883	71,250		44,919
Proceeds from the issuance of common units, net of offering expenses					(183)		25,000
Distributions to unitholders	[5]				381,771		313,380
Above-market component of swap agreements with Anadarko			16,373	9,552	$ 28,670	[5]	16,365	[5]
Units issued					385,195
Springfield [Member] | Common Units [Member]
Related Party Transaction [Line Items]
Units issued	[6]	2,089,602
Affiliates [Member]
Related Party Transaction [Line Items]
Revenues and other	[1]		316,313	302,405	$ 631,468		574,989
Cost of product	[1]		21,607	22,145	37,595		46,725
Operation and maintenance	[7]		18,462	17,661	35,551		35,636
General and administrative	[8]		9,365	9,169	18,900		18,121
Operating expenses			49,434	48,975	92,046		100,482
Interest expense	[9]		0	(15,461)	71		(10,924)
Settlement of the Deferred purchase price obligation - Anadarko	[10]				(37,346)		0
Proceeds from the issuance of common units, net of offering expenses	[11]		0	0	0		25,000
Distributions to unitholders	[12]		110,449	94,909	213,572		184,678
Affiliates [Member] | Deferred Purchase Price Obligation - Anadarko [Member]
Related Party Transaction [Line Items]
Settlement of the Deferred purchase price obligation - Anadarko	[13]		$ (37,346)	$ 0	$ (37,346)		$ 0
Western Gas Equity Partners, LP [Member] | Springfield [Member] | Common Units [Member]
Related Party Transaction [Line Items]
Units issued		835,841
[1]	Represents amounts earned or incurred on and subsequent to the date of the acquisition of Partnership assets, as well as amounts earned or incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets, recognized under gathering, treating or processing agreements, and purchase and sale agreements.
[2]	Cost of product includes product purchases from Anadarko (as defined in Note 1) of $21.6 million and $37.6 million for the three and six months ended June 30, 2017, respectively, and $22.1 million and $46.7 million for the three and six months ended June 30, 2016, respectively. Operation and maintenance includes charges from Anadarko of $18.5 million and $35.6 million for the three and six months ended June 30, 2017, respectively, and $17.7 million and $35.6 million for the three and six months ended June 30, 2016, respectively. General and administrative includes charges from Anadarko of $9.4 million and $18.9 million for the three and six months ended June 30, 2017, respectively, and $9.2 million and $18.1 million for the three and six months ended June 30, 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 zero and $(0.1) million for the three and six months ended June 30, 2017, respectively, and $15.5 million and $10.9 million for the three and six months ended June 30, 2016, respectively. See Note 2 and Note 9.
[5]	See Note 5.
[6]	The Partnership acquired Springfield Pipeline LLC (“Springfield”) from Anadarko for $750.0 million, consisting of $712.5 million in cash and the issuance of 1,253,761 of the Partnership’s common units. Springfield owns a 50.1% interest in an oil gathering system and a gas gathering system, such interest being referred to in this report as the “Springfield interest.” The Springfield oil and gas gathering systems (collectively, the “Springfield system”) are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. The Partnership financed the cash portion of the acquisition through: (i) borrowings of $247.5 million on the Partnership’s senior unsecured revolving credit facility (“RCF”), (ii) the issuance of 835,841 of the Partnership’s common units to WGP and (iii) the issuance of Series A Preferred units to private investors. See Note 4 for further information regarding the Series A Preferred units.
[7]	Represents expenses incurred on and subsequent to the date of the acquisition of Partnership assets, as well as expenses incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets.
[8]	Represents general and administrative expense incurred on and subsequent to the date of the Partnership’s acquisition of the Partnership assets, as well as a management services fee for reimbursement of expenses incurred by Anadarko for periods prior to the acquisition of the Partnership assets by the Partnership. These amounts include equity-based compensation expense allocated to the Partnership by Anadarko (see WES LTIP and WGP LTIP and Anadarko Incentive Plan within this Note 5).
[9]	Includes amounts related to the Deferred purchase price obligation - Anadarko (see Note 2 and Note 9).
[10]	See Note 2.
[11]	Represents proceeds from the issuance of 835,841 common units to WGP as partial funding for the acquisition of Springfield (see Note 2).
[12]	Represents distributions paid under the partnership agreement (see Note 3 and Note 4).
[13]	Represents the cash payment to Anadarko for the settlement of the Deferred purchase price obligation - Anadarko (see Note 2).

Transactions with Affiliates 44

Transactions with Affiliates - Additional Information (Details) - USD ($)		1 Months Ended	3 Months Ended		6 Months Ended
		May 31, 2008	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Note receivable - Anadarko			$ 260,000,000		$ 260,000,000		$ 260,000,000
Above-market component of swap agreements with Anadarko	[1]				28,670,000
Contributions of equity-based compensation from Anadarko					$ 2,236,000
Western Gas Partners Long Term Incentive Plan [Member]
Related Party Transaction [Line Items]
Units vesting period					3 years
Equity-based compensation expense			100,000	$ 100,000	$ 200,000	$ 200,000
Western Gas Equity Partners Long Term Incentive Plan [Member] | Anadarko Incentive Plan [Member]
Related Party Transaction [Line Items]
Equity-based compensation expense			$ 900,000	$ 1,100,000	2,100,000	$ 2,400,000
Contributions of equity-based compensation from Anadarko					$ 2,236,000
Natural Gas [Member] | Gathering, Treating and Transportation [Member]
Related Party Transaction [Line Items]
Affiliate throughput percent			38.00%	39.00%	34.00%	38.00%
Natural Gas [Member] | Processing [Member]
Related Party Transaction [Line Items]
Affiliate throughput percent			39.00%	55.00%	44.00%	58.00%
Crude, NGL and Produced Water [Member] | Gathering, Treating and Transportation [Member]
Related Party Transaction [Line Items]
Affiliate throughput percent			41.00%	64.00%	47.00%	64.00%
Affiliates [Member]
Related Party Transaction [Line Items]
Note receivable - Anadarko		$ 260,000,000
Note receivable, due date		May 14, 2038
Fixed annual rate for note receivable bearing interest		6.50%
Affiliates [Member] | Level 2 Inputs [Member] | Market Approach Valuation Technique [Member]
Related Party Transaction [Line Items]
Fair value of the note receivable			$ 311,300,000		$ 311,300,000		$ 313,300,000
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	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 7,354,782	$ 6,861,942
Accumulated depreciation	2,006,988	1,812,010
Net property, plant and equipment	5,347,794	5,049,932
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	4,258	4,012
Gathering Systems and Processing Complexes [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 6,905,758	6,462,053
Gathering Systems and Processing Complexes [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Gathering Systems and Processing Complexes [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	47 years
Pipelines and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 139,344	139,646
Pipelines and Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	15 years
Pipelines and Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	45 years
Assets Under Construction [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 275,403	226,626
Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 30,019	$ 29,605
Other [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Other [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	40 years

Property, Plant and Equipment46

Property, Plant and Equipment - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended		12 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Impairments		$ 3,178	$ 2,403	$ 167,920	$ 8,921	$ 15,500
Equity investment impairment loss	[1]			3,110
Fort Union [Member]
Property, Plant and Equipment [Line Items]
Equity investment impairment loss	[1]			3,110
Granger Complex [Member]
Property, Plant and Equipment [Line Items]
Impairments				158,800
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		48,500
Equipment [Member]
Property, Plant and Equipment [Line Items]
Impairments				9,100		9,400
Granger Straddle Plant [Member]
Property, Plant and Equipment [Line Items]
Impairments				3,700
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		$ 600
Newcastle System [Member]
Property, Plant and Equipment [Line Items]
Impairments						6,100
Newcastle System [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3 Inputs [Member] | Income Approach Valuation Technique [Member]
Property, Plant and Equipment [Line Items]
Estimated fair value						$ 3,100
[1]	Recorded in Impairments in the consolidated statements of operations.

Equity Investments - Equity Inv

Equity Investments - Equity Investments Table (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017		Jun. 30, 2016
Schedule of Equity Method Investments [Line Items]
Balance				$ 594,208
Investment earnings (loss), net of amortization	[1]	$ 21,728	$ 19,693	41,189		$ 36,507
Impairment expense	[2]			(3,110)
Contributions				287		(139)
Distributions				(42,202)		(38,519)
Distributions in excess of cumulative earnings				(9,221)	[3]	$ (10,611)
Balance		581,151		581,151
Fort Union [Member]
Schedule of Equity Method Investments [Line Items]
Balance				12,833
Investment earnings (loss), net of amortization				1,844
Impairment expense	[2]			(3,110)
Contributions				0
Distributions				(2,239)
Distributions in excess of cumulative earnings	[3]			(800)
Balance		8,528		8,528
White Cliffs [Member]
Schedule of Equity Method Investments [Line Items]
Balance				47,319
Investment earnings (loss), net of amortization				6,701
Impairment expense	[2]			0
Contributions				277
Distributions				(6,410)
Distributions in excess of cumulative earnings	[3]			(1,571)
Balance		46,316		46,316
Rendezvous [Member]
Schedule of Equity Method Investments [Line Items]
Balance				46,739
Investment earnings (loss), net of amortization				540
Impairment expense	[2]			0
Contributions				0
Distributions				(1,510)
Distributions in excess of cumulative earnings	[3]			(1,418)
Balance		44,351		44,351
Mont Belvieu JV [Member]
Schedule of Equity Method Investments [Line Items]
Balance				112,805
Investment earnings (loss), net of amortization				13,388
Impairment expense	[2]			0
Contributions				0
Distributions				(13,407)
Distributions in excess of cumulative earnings	[3]			(1,717)
Balance		111,069		111,069
Texas Express Gathering LLC [Member]
Schedule of Equity Method Investments [Line Items]
Balance				15,846
Investment earnings (loss), net of amortization				1,319
Impairment expense	[2]			0
Contributions				0
Distributions				(1,026)
Distributions in excess of cumulative earnings	[3]			0
Balance		16,139		16,139
Texas Express Pipeline LLC [Member]
Schedule of Equity Method Investments [Line Items]
Balance				189,194
Investment earnings (loss), net of amortization				8,956
Impairment expense	[2]			0
Contributions				10
Distributions				(9,082)
Distributions in excess of cumulative earnings	[3]			(2,102)
Balance		186,976		186,976
Front Range Pipeline LLC [Member]
Schedule of Equity Method Investments [Line Items]
Balance				169,472
Investment earnings (loss), net of amortization				8,441
Impairment expense	[2]			0
Contributions				0
Distributions				(8,528)
Distributions in excess of cumulative earnings	[3]			(1,613)
Balance		$ 167,772		$ 167,772
[1]	Represents amounts earned or incurred on and subsequent to the date of the acquisition of Partnership assets, as well as amounts earned or incurred by Anadarko on a historical basis related to the Partnership assets prior to the acquisition of such assets, recognized under gathering, treating or processing agreements, and purchase and sale agreements.
[2]	Recorded in Impairments in the consolidated statements of operations.
[3]	Distributions in excess of cumulative earnings, classified as investing cash flows in the consolidated statements of cash flows, is calculated on an individual investment basis.

Equity Investments - Additional

Equity Investments - Additional Information (Details) - Fort Union [Member] $ in Millions	Jun. 30, 2017USD ($)
Schedule of Equity Method Investments [Line Items]
Equity investment difference between carrying and underlying value	$ 3.1
Income Approach Valuation Technique [Member] | Level 3 Inputs [Member] | Fair Value, Measurements, Nonrecurring [Member]
Schedule of Equity Method Investments [Line Items]
Equity investment fair value	$ 8.5

Components of Working Capital -

Components of Working Capital - Accounts Receivable, Net Table (Details) - USD ($) $ in Thousands		Jun. 30, 2017	Dec. 31, 2016
Receivables [Abstract]
Trade receivables, net		$ 136,398	$ 192,808
Other receivables, net		46	30,415
Total accounts receivable, net	[1]	$ 136,444	$ 223,223
[1]	Accounts receivable, net includes amounts receivable from affiliates (as defined in Note 1) of $63.0 million and $76.6 million as of June 30, 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 Capital50

Components of Working Capital - Other Current Assets Table (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Other Current Assets [Line Items]
Natural gas liquids inventory	$ 8,869	$ 7,126
Imbalance receivables	1,020	3,483
Prepaid insurance	272	2,257
Total other current assets	$ 10,161	$ 12,866

Components of Working Capital51

Components of Working Capital - Accrued Liabilities Table (Details) - USD ($) $ in Thousands		Jun. 30, 2017	Dec. 31, 2016
Components Of Working Capital [Abstract]
Accrued interest expense		$ 40,541	$ 39,826
Short-term asset retirement obligations		6,191	3,114
Short-term remediation and reclamation obligations		630	630
Income taxes payable		1,634	1,006
Other accrued liabilities		7,844	532
Total accrued liabilities	[1]	$ 56,840	$ 45,108
[1]	Accrued liabilities includes affiliate amounts of $0.3 million and zero as of June 30, 2017, and December 31, 2016, respectively.

Debt and Interest Expense - Deb

Debt and Interest Expense - Debt Outstanding Table (Details) - USD ($)		Jun. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Total long-term debt principal		$ 3,280,000,000	$ 3,120,000,000
Carrying value		3,253,065,000	3,091,461,000
Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[1]	3,367,732,000	3,196,199,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Principal		160,000,000	0
Carrying value		160,000,000	0
Revolving Credit Facility [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[1]	160,000,000	0
Senior Notes [Member] | 5.375% Senior Notes due 2021 [Member]
Debt Instrument [Line Items]
Principal		500,000,000	500,000,000
Carrying value		495,268,000	494,734,000
Senior Notes [Member] | 5.375% Senior Notes due 2021 [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[1]	537,476,000	536,252,000
Senior Notes [Member] | 4.000% Senior Notes due 2022 [Member]
Debt Instrument [Line Items]
Principal		670,000,000	670,000,000
Carrying value		668,740,000	668,634,000
Senior Notes [Member] | 4.000% Senior Notes due 2022 [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[1]	686,001,000	681,723,000
Senior Notes [Member] | 2.600% Senior Notes due 2018 [Member]
Debt Instrument [Line Items]
Principal		350,000,000	350,000,000
Carrying value		349,434,000	349,188,000
Senior Notes [Member] | 2.600% Senior Notes due 2018 [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[1]	351,057,000	351,531,000
Senior Notes [Member] | 5.450% Senior Notes due 2044 [Member]
Debt Instrument [Line Items]
Principal		600,000,000	600,000,000
Carrying value		593,179,000	593,132,000
Senior Notes [Member] | 5.450% Senior Notes due 2044 [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[1]	618,294,000	615,753,000
Senior Notes [Member] | 3.950% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Principal		500,000,000	500,000,000
Carrying value		491,423,000	490,971,000
Senior Notes [Member] | 3.950% Senior Notes due 2025 [Member] | Market Approach Valuation Technique [Member] | Level 2 Inputs [Member]
Debt Instrument [Line Items]
Fair value	[1]	497,615,000	492,499,000
Senior Notes [Member] | 4.650% Senior Notes due 2026 [Member]
Debt Instrument [Line Items]
Principal		500,000,000	500,000,000
Carrying value		495,021,000	494,802,000
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]	$ 517,289,000	$ 518,441,000
[1]	Fair value is measured using the market approach and Level 2 inputs.

Debt and Interest Expense - D53

Debt and Interest Expense - Debt Activity Table (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2017USD ($)
Debt Instrument [Line Items]
Beginning balance	$ 3,091,461
Other	1,604
Ending balance	3,253,065
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Beginning balance	0
RCF borrowings	160,000
Ending balance	$ 160,000

Debt and Interest Expense - Int

Debt and Interest Expense - Interest Expense Table (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Debt Instrument [Line Items]
Interest expense	[1]	$ (35,746)	$ (12,883)	$ (71,250)	$ (44,919)
Third Parties [Member]
Debt Instrument [Line Items]
Long-term debt		(35,161)	(28,281)	(69,780)	(56,099)
Amortization of debt issuance costs and commitment fees		(1,645)	(1,545)	(3,275)	(3,075)
Capitalized interest		1,060	1,482	1,876	3,331
Interest expense		(35,746)	(28,344)	(71,179)	(55,843)
Affiliates [Member]
Debt Instrument [Line Items]
Interest expense	[2]	0	15,461	(71)	10,924
Affiliates [Member] | Deferred Purchase Price Obligation - Anadarko [Member]
Debt Instrument [Line Items]
Deferred purchase price obligation - Anadarko	[3]	$ 0	$ 15,461	$ (71)	$ 10,924
[1]	Includes affiliate (as defined in Note 1) amounts of zero and $(0.1) million for the three and six months ended June 30, 2017, respectively, and $15.5 million and $10.9 million for the three and six months ended June 30, 2016, respectively. See Note 2 and Note 9.
[2]	Includes amounts related to the 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 ($)	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility, outstanding borrowings	$ 160,000,000
Outstanding letters of credit	4,900,000
Facility, available borrowing capacity	$ 1,035,000,000
Facility, interest rate at period end	2.53%	1.77%
Facility, fee rate	0.20%	0.20%
Facility, expiration date	Feb. 26, 2020
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
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
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
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
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
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) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Committed capital	$ 53.6		$ 53.6
Rent expense associated with office, warehouse and equipment leases	$ 11.5	$ 8.4	$ 19.4	$ 17.3