Equity and Partners' Capital - Calculation of WES Operating Net Income (Loss) Per Unit Table (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Earnings Per Unit [Line Items]
Net income (loss) attributable to Western Midstream Operating, LP		$ 118,660	$ 131,527	[1]
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]
WES Operating [Member]
Earnings Per Unit [Line Items]
Net income (loss) attributable to Western Midstream Operating, LP		212,596	179,885	[1]
Pre-acquisition net (income) loss allocated to Anadarko		(29,116)	(30,522)	[1]
General partner interest in net (income) loss	[2]	$ 0	(83,439)	[1]
WES Operating [Member] | Common and Class C Units [Member]
Earnings Per Unit [Line Items]
Limited partners' interest in net income (loss)			65,924
WES Operating [Member] | Common Units [Member]
Earnings Per Unit [Line Items]
Limited partners' interest in net income (loss)	[3]		$ 58,323
Net income (loss) per common unit - basic and diluted	[1],[2],[4]		$ 0.38
Weighted-average common units outstanding - basic and diluted			152,602
WES Operating [Member] | Class C Units [Member]
Earnings Per Unit [Line Items]
Limited partners' interest in net income (loss)	[3]		$ 7,601
Anti-dilutive units excluded from computation of earnings per unit	[4]		13,380

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

[2] See Note 5 for the calculation of net income (loss) per common unit.

[3] Adjusted to reflect amortization of the beneficial conversion feature.

[4] The impact of Class C units would be anti-dilutive for the period presented.