Equity and Partners' Capital - Calculation of WES Operating Net Income (Loss) Per Unit Table (Details) - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Unit [Line Items]
Net income (loss) attributable to Western Midstream Operating, LP		$ 527,012	$ 697,241	$ 551,571
Pre-acquisition net (income) loss allocated to Anadarko		0	(29,279)	(182,142)
General partner interest in net (income) loss		(11,104)	(5,637)	0
Limited partners' interest in net income (loss)	[1]	515,908	662,325	369,429
WES Operating [Member]
Earnings Per Unit [Line Items]
Net income (loss) attributable to Western Midstream Operating, LP		541,377	807,590	627,917
Pre-acquisition net (income) loss allocated to Anadarko		0	(29,279)	(182,142)
General partner interest in net (income) loss	[2]	$ 0	$ 0	(346,538)
WES Operating [Member] | Common and Class C Units [Member]
Earnings Per Unit [Line Items]
Limited partners' interest in net income (loss)				99,237
WES Operating [Member] | Common Units [Member]
Earnings Per Unit [Line Items]
Limited partners' interest in net income (loss)				$ 84,334
Weighted-average common units outstanding - basic and diluted				152,606
WES Operating [Member] | Class C Units [Member]
Earnings Per Unit [Line Items]
Limited partners' interest in net income (loss)				$ 14,903
Anti-dilutive units excluded from computation of earnings per unit				13,795

[1] See Note 5.

[2] See Note 5.