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Description of Business and Basis of Presentation - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Mar. 22, 2021
Defined-contribution plan expense	$ 5.3	$ 3.8	$ 18.3	$ 8.2
Long-Term Incentive Plans [Member]
Common units issued under the WES LTIP, number of units			357,472
Equity-based compensation expense	$ 4.7	$ 2.1	$ 12.9	$ 5.4
Western Midstream Partners, LP 2021 Long-Term Incentive Plan [Member]
Units authorized under LTIP					9,500,000
WES Operating [Member]
Ownership interest by noncontrolling interest owner	2.00%		2.00%
Chipeta [Member]
Ownership interest by noncontrolling interest owner	25.00%		25.00%
WES [Member] \| WES Operating [Member]
Ownership interest			98.00%