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Debt and Interest Expense - Debt Activity Table (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Jan. 13, 2020
Changes in Debt Outstanding [Roll Forward]
Beginning balance		$ 7,854,702
Other		8,046
Ending balance	$ 7,126,303	7,126,303
WES Operating [Member] \| Senior Notes [Member]
Changes in Debt Outstanding [Roll Forward]
Repayments of senior notes	$ (500,000)
WES Operating [Member] \| RCF [Member] \| Revolving Credit Facility [Member]
Changes in Debt Outstanding [Roll Forward]
Facility borrowings		400,000
Repayments of facility borrowings		(180,000)
WES Operating [Member] \| 5.375% Senior Notes due 2021 [Member] \| Senior Notes [Member]
Changes in Debt Outstanding [Roll Forward]
Repayments of senior notes		$ (431,081)
Senior note, interest rate	5.375%	5.375%
WES Operating [Member] \| 4.000% Senior Notes due 2022 [Member] \| Senior Notes [Member]
Changes in Debt Outstanding [Roll Forward]
Repayments of senior notes		$ (78,671)
Senior note, interest rate	4.00%	4.00%
WES Operating [Member] \| Floating-Rate Senior Notes due 2023 [Member] \| Senior Notes [Member]
Changes in Debt Outstanding [Roll Forward]
Repayments of senior notes		$ (26,840)
WES Operating [Member] \| 3.100% Senior Notes due 2025 [Member] \| Senior Notes [Member]
Changes in Debt Outstanding [Roll Forward]
Repayments of senior notes		$ (267,894)
Senior note, interest rate	3.10%	3.10%	3.10%
WES Operating [Member] \| 3.950% Senior Notes due 2025 [Member] \| Senior Notes [Member]
Changes in Debt Outstanding [Roll Forward]
Repayments of senior notes		$ (100,837)
Senior note, interest rate	3.95%	3.95%
WES Operating [Member] \| 4.650% Senior Notes due 2026 [Member] \| Senior Notes [Member]
Changes in Debt Outstanding [Roll Forward]
Repayments of senior notes		$ (25,758)
Senior note, interest rate	4.65%	4.65%
WES Operating [Member] \| Finance Lease Liability [Member]
Changes in Debt Outstanding [Roll Forward]
Finance lease liabilities		$ (25,364)