Consolidated Statements of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities
Net income (loss)		$ 807,700	$ 630,654	$ 737,385
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization		483,255	389,164	318,771
Impairments		6,279	230,584	180,051
Non-cash equity-based compensation expense		15,494	6,431	5,169
Deferred income taxes		7,609	139,048	(53,138)
Accretion and amortization of long-term obligations, net		8,441	5,943	4,932
Equity income, net – affiliates		(237,518)	(195,469)	(115,141)
Distributions from equity-investment earnings – affiliates		234,572	187,392	117,093
(Gain) loss on divestiture and other, net	[1],[2]	1,406	(1,312)	(132,388)
(Gain) loss on interest-rate swaps		125,334	7,972	0
Cash paid to settle interest-rate swaps		(107,685)	0	0
Lower of cost or market inventory adjustments		236	752	145
Changes in assets and liabilities:
(Increase) decrease in accounts receivable, net		(45,033)	(60,502)	(16,244)
Increase (decrease) in accounts and imbalance payables and accrued liabilities, net		(30,866)	45,605	(937)
Change in other items, net		54,876	(38,087)	(2,983)
Net cash provided by operating activities		1,324,100	1,348,175	1,042,715
Cash flows from investing activities
Capital expenditures		(1,188,829)	(1,948,595)	(1,028,319)
Investments in equity affiliates		(128,393)	(133,629)	(2,884)
Distributions from equity investments in excess of cumulative earnings – affiliates		30,256	29,585	31,659
Proceeds from property insurance claims		0	0	22,977
Net cash used in investing activities		(3,387,853)	(2,210,813)	(1,133,324)
Cash flows from financing activities
Borrowings, net of debt issuance costs	[3]	4,169,695	2,671,337	468,803
Repayments of debt	[4]	(1,467,595)	(1,040,000)	0
Increase (decrease) in outstanding checks		1,571	(3,206)	5,593
Registration expenses related to the issuance of Partnership common units		(855)	0	0
Distributions to Partnership unitholders	[5]	(969,073)	(502,457)	(441,967)
Net contributions from (distributions to) Anadarko		458,819	97,755	126,866
Above-market component of swap agreements with Anadarko	[5]	7,407	51,618	58,551
Finance lease payments – affiliates		(508)
Net cash provided by (used in) financing activities		2,071,573	875,192	(188,875)
Net increase (decrease) in cash and cash equivalents		7,820	12,554	(279,484)
Cash and cash equivalents at beginning of period		92,142	79,588	359,072
Cash and cash equivalents at end of period		99,962	92,142	79,588
Supplemental disclosures
Accretion expense and revisions to the Deferred purchase price obligation – Anadarko	[6]	0	0	(4,094)
Net distributions to (contributions from) Anadarko of other assets		90	(58,835)	(3,189)
Interest paid, net of capitalized interest		293,795	140,720	136,624
Taxes paid (reimbursements received)		96	2,408	1,194
Accrued capital expenditures		140,954	274,632	312,720
Fair value of properties and equipment from non-cash third-party transactions	[6]	0	0	551,453
Chipeta [Member]
Cash flows from financing activities
Distributions to Chipeta noncontrolling interest owner		(9,663)	(13,529)	(13,569)
WES Operating [Member]
Cash flows from financing activities
Distributions to noncontrolling interest owner		(118,225)	(386,326)	(355,623)
WES Operating [Member]
Cash flows from operating activities
Net income (loss)		814,685	636,526	742,401
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization		483,255	389,164	318,771
Impairments		6,279	230,584	180,051
Non-cash equity-based compensation expense		14,235	6,153	4,922
Deferred income taxes		7,609	139,048	(53,138)
Accretion and amortization of long-term obligations, net		8,421	5,142	4,254
Equity income, net – affiliates		(237,518)	(195,469)	(115,141)
Distributions from equity-investment earnings – affiliates		234,572	187,392	117,093
(Gain) loss on divestiture and other, net	[7],[8]	1,406	(1,312)	(132,388)
(Gain) loss on interest-rate swaps		125,334	7,972	0
Cash paid to settle interest-rate swaps		(107,685)	0	0
Lower of cost or market inventory adjustments		236	752	145
Changes in assets and liabilities:
(Increase) decrease in accounts receivable, net		(44,939)	(60,460)	(16,177)
Increase (decrease) in accounts and imbalance payables and accrued liabilities, net		(29,745)	44,424	(947)
Change in other items, net		56,044	(37,802)	(3,048)
Net cash provided by operating activities		1,332,189	1,352,114	1,046,798
Cash flows from investing activities
Capital expenditures		(1,188,829)	(1,948,595)	(1,028,319)
Investments in equity affiliates		(128,393)	(133,629)	(2,884)
Distributions from equity investments in excess of cumulative earnings – affiliates		30,256	29,585	31,659
Proceeds from property insurance claims		0	0	22,977
Net cash used in investing activities		(3,387,853)	(2,210,813)	(1,133,324)
Cash flows from financing activities
Borrowings, net of debt issuance costs	[9]	4,169,695	2,671,344	468,803
Repayments of debt	[10]	(1,439,595)	(1,040,000)	0
Increase (decrease) in outstanding checks		1,571	(3,206)	5,593
Proceeds from the issuance of common units, net of offering expenses		0	0	(183)
Distributions to Partnership unitholders	[11]	(1,124,388)	(893,649)	(801,300)
Net contributions from (distributions to) Anadarko		458,819	97,755	126,866
Above-market component of swap agreements with Anadarko	[11]	7,407	51,618	58,551
Net cash provided by (used in) financing activities		2,063,338	870,333	(192,585)
Net increase (decrease) in cash and cash equivalents		7,674	11,634	(279,111)
Cash and cash equivalents at beginning of period		90,448	78,814	357,925
Cash and cash equivalents at end of period		98,122	90,448	78,814
Supplemental disclosures
Accretion expense and revisions to the Deferred purchase price obligation – Anadarko	[12]	0	0	(4,094)
Net distributions to (contributions from) Anadarko of other assets		90	(58,835)	(3,189)
Interest paid, net of capitalized interest		293,561	139,482	135,079
Taxes paid (reimbursements received)		96	2,408	1,194
Accrued capital expenditures		140,954	274,632	312,720
Fair value of properties and equipment from non-cash third-party transactions	[12]	0	0	551,453
WES Operating [Member] | Chipeta [Member]
Cash flows from financing activities
Distributions to Chipeta noncontrolling interest owner		(9,663)	(13,529)	(13,569)
Affiliates [Member]
Cash flows from investing activities
Contributions in aid of construction costs from affiliates		0	0	1,387
Acquisitions		(2,007,926)	(254)	(3,910)
Cash flows from financing activities
Borrowings, net of debt issuance costs		11,000	321,800
Repayments of debt		(439,600)
Settlement of the Deferred purchase price obligation – Anadarko	[6]	0	0	(37,346)
Distributions to Partnership unitholders		(566,868)	(400,194)	(360,523)
Finance lease payments – affiliates		(508)	0	0
Affiliates [Member] | WES Operating [Member]
Cash flows from financing activities
Distributions to Partnership unitholders		(19,768)	(7,583)	(7,100)
Affiliates [Member] | WES Operating [Member]
Cash flows from investing activities
Contributions in aid of construction costs from affiliates		0	0	1,387
Acquisitions		(2,007,926)	(254)	(3,910)
Cash flows from financing activities
Borrowings, net of debt issuance costs		11,000	321,800
Repayments of debt		(439,600)
Settlement of the Deferred purchase price obligation – Anadarko	[12]	0	0	(37,346)
Distributions to Partnership unitholders		(1,025,931)	(514,906)	(452,777)
Finance lease payments – affiliates		(508)	0	0
Third Parties [Member]
Cash flows from investing activities
Acquisitions		(93,303)	(161,858)	(177,798)
Proceeds from the sale of assets		342	3,938	23,564
Third Parties [Member] | WES Operating [Member]
Cash flows from investing activities
Acquisitions		(93,303)	(161,858)	(177,798)
Proceeds from the sale of assets		$ 342	$ 3,938	$ 23,564

[1] Includes losses related to an incident at the DBM complex for the year ended December 31, 2017. See Note 1.

[2] Includes losses related to an incident at the DBM complex for the year ended December 31, 2017. See Note 1.

[3] For the years ended December 31, 2019 and 2018, includes $11.0 million and $321.8 million of borrowings, respectively, under the APCWH Note Payable.

[4] For the year ended December 31, 2019, includes a $439.6 million repayment to settle the APCWH Note Payable. See Note 6.

[5] See Note 6.

[6] See Note 3.

[7] Includes losses related to an incident at the DBM complex for the year ended December 31, 2017. See Note 1.

[8] Includes losses related to an incident at the DBM complex for the year ended December 31, 2017. See Note 1.

[9] For the years ended December 31, 2019 and 2018, includes $11.0 million and $321.8 million of borrowings, respectively, under the APCWH Note Payable.

[10] For the year ended December 31, 2019, includes a $439.6 million repayment to settle the APCWH Note Payable. See Note 6.

[11] See Note 6.

[12] See Note 3.