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			9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018		Sep. 30, 2019	Sep. 30, 2018
Earnings Per Unit [Line Items]
Net income (loss) attributable to Western Midstream Operating, LP		$ 121,217	$ 151,357	[1]	$ 409,471	$ 383,068	[1]
Pre-acquisition net (income) loss allocated to Anadarko		0	(43,883)	[1]	(29,279)	(107,009)	[1]
Limited partners' interest in net income (loss)		121,217	107,474	[1]	380,192	276,059	[1]
WES Operating [Member]
Earnings Per Unit [Line Items]
Net income (loss) attributable to Western Midstream Operating, LP		125,415	198,529	[1]	513,023	443,726	[1]
Pre-acquisition net (income) loss allocated to Anadarko		0	(43,883)	[1]	(29,279)	(107,009)	[1]
General partner interest in net (income) loss	[2]	$ 0	(88,551)	[1]	$ 0	(256,166)	[1]
WES Operating [Member] | Common and Class C Units [Member]
Earnings Per Unit [Line Items]
Limited partners' interest in net income (loss)			66,095			80,551
WES Operating [Member] | Common Units [Member]
Earnings Per Unit [Line Items]
Limited partners' interest in net income (loss)			$ 59,732			$ 69,638
Net income (loss) per common unit - basic and diluted	[1],[2]		$ 0.39			$ 0.46
Weighted-average common units outstanding - basic and diluted			152,609			152,605
WES Operating [Member] | Class C Units [Member]
Earnings Per Unit [Line Items]
Limited partners' interest in net income (loss)			$ 6,363			$ 10,913
Anti-dilutive units excluded from computation of earnings per unit			13,921			13,652

[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.