Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands		3 Months Ended			12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018		Dec. 31, 2018
Revenues and Other
Revenues and other		$ 671,883	$ 501,054	[1]
Equity income, net – affiliates	[2]	57,992	30,229	[1]
Operating expenses
Cost of product	[3]	114,063	94,318	[1]
Operation and maintenance	[3]	142,829	96,795	[1]
General and administrative	[3]	22,844	15,829	[1]
Property and other taxes		16,285	14,600	[1]
Depreciation and amortization		113,946	84,790	[1]
Impairments		390	200	[1]	$ 230,600
Total operating expenses		410,357	306,532	[1]
Gain (loss) on divestiture and other, net		(590)	116	[1]
Operating income (loss)		318,928	224,867	[1]
Interest income – affiliates	[4]	4,225	4,225	[1]
Interest expense	[5]	(65,876)	(38,015)	[1]
Other income (expense), net		(35,206)	817	[1]
Income (loss) before income taxes		222,071	191,894	[1]
Income tax expense (benefit)		10,092	10,884	[1]
Net income (loss)		211,979	181,010	[1]
Net income (loss) attributable to noncontrolling interests		93,319	49,483	[1]
Net income (loss) attributable to Western Midstream Partners, LP		118,660	131,527	[1]
Limited partners' interest in net income (loss):
Pre-acquisition net (income) loss allocated to Anadarko		(29,116)	(30,522)	[1]
Limited partners' interest in net income (loss)		89,544	101,005	[1]
Affiliates [Member]
Revenues and Other
Revenues and other	[2]	378,437	285,176	[1]
Operating expenses
Cost of product	[2]	56,172	34,819
Operation and maintenance	[2]	39,141	23,001
General and administrative	[6]	18,894	12,688
Total operating expenses		114,207	70,508
Interest expense	[7]	(1,833)	(577)
Affiliates [Member] | Service Revenues - Fee Based [Member]
Revenues and Other
Revenues and other		326,642	222,038	[1]
Affiliates [Member] | Service Revenues - Product Based [Member]
Revenues and Other
Revenues and other		1,352	631	[1]
Affiliates [Member] | Product Sales [Member]
Revenues and Other
Revenues and other		50,443	62,507	[1]
Third Parties [Member]
Revenues and Other
Revenues and other		293,446	215,878	[1]
Operating expenses
Interest expense		(64,043)	(37,438)
Third Parties [Member] | Service Revenues - Fee Based [Member]
Revenues and Other
Revenues and other		253,332	171,735	[1]
Third Parties [Member] | Service Revenues - Product Based [Member]
Revenues and Other
Revenues and other		18,027	22,792	[1]
Third Parties [Member] | Product Sales [Member]
Revenues and Other
Revenues and other		21,690	21,118	[1]
Third Parties [Member] | Other [Member]
Revenues and Other
Revenues and other		$ 397	$ 233	[1]
Limited Partner [Member]
Limited partners' interest in net income (loss):
Net income (loss) per common unit - basic and diluted		$ 0.30	$ 0.46	[1]
Weighted-average common units outstanding - basic and diluted		299,556	218,933	[1]

[1] Financial information has been recast to include the financial position and results attributable to AMA. See Note 1 and Note 3.

[2] 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.

[3] Cost of product includes product purchases from affiliates (as defined in Note 1) of $56.2 million and $34.8 million for the three months ended March 31, 2019 and 2018, respectively. Operation and maintenance includes charges from affiliates of $39.1 million and $23.0 million for the three months ended March 31, 2019 and 2018, respectively. General and administrative includes charges from affiliates of $18.9 million and $12.7 million for the three months ended March 31, 2019 and 2018, respectively. See Note 6.

[4] Represents interest income recognized on the note receivable from Anadarko.

[5] Includes affiliate (as defined in Note 1) amounts of $1.8 million and $0.6 million for the three months ended March 31, 2019 and 2018, respectively. See Note 1 and Note 10.

[6] Represents general and administrative expense incurred on and subsequent to the date of the acquisition of Partnership assets, as well as a management services fee for expenses incurred by Anadarko for periods prior to the acquisition of such assets. These amounts include equity-based compensation expense allocated to the Partnership by Anadarko (see LTIPs and Anadarko Incentive Plan within this Note 6) and amounts charged by Anadarko under the omnibus agreements of the Partnership and WES Operating.

[7] Includes amounts related to the APCWH Note Payable (see Note 1 and Note 10).