Debt and Interest Expense - Additional Information (Details) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Jan. 13, 2020
Debt Instrument [Line Items]
Gain (loss) on early extinguishment of debt	$ (24,655,000)	$ 1,632,000		$ (24,944,000)	$ 10,372,000
Finance leases - Net property, plant, and equipment	19,600,000			19,600,000
Finance leases - Debt	20,300,000			20,300,000
Operating leases - Other assets	4,800,000			4,800,000
Operating leases - Accrued liabilities	3,100,000			3,100,000
Operating leases - Other liabilities	2,400,000			2,400,000
WES Operating [Member]
Debt Instrument [Line Items]
Gain (loss) on early extinguishment of debt	(24,655,000)	$ 1,632,000		(24,944,000)	$ 10,372,000
WES Operating [Member] | Third Parties [Member]
Debt Instrument [Line Items]
Future lease payments	6,700,000			$ 6,700,000
WES Operating [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Repayments of Debt	500,000,000
Gain (loss) on early extinguishment of debt	$ (24,700,000)
WES Operating [Member] | 3.100% Senior Notes due 2025 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Senior note, interest rate	3.10%			3.10%		3.10%
Senior note, effective interest rate	4.542%	4.291%		4.542%	4.291%
Repayments of Debt				$ 267,894,000
WES Operating [Member] | 4.050% Senior Notes due 2030 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Senior note, interest rate	4.05%			4.05%		4.05%
Senior note, effective interest rate	5.424%	5.173%		5.424%	5.173%
WES Operating [Member] | 5.250% Senior Notes due 2050 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Senior note, interest rate	5.25%			5.25%		5.25%
Senior note, effective interest rate	6.629%	6.375%		6.629%	6.375%
WES Operating [Member] | Floating-Rate Senior Notes due 2023 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Senior note, effective interest rate	2.23%	2.12%		2.23%	2.12%
Repayments of Debt				$ 26,840,000
WES Operating [Member] | 5.375% Senior Notes due 2021 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Senior note, interest rate	5.375%			5.375%
Repayments of Debt				$ 431,081,000
WES Operating [Member] | 4.000% Senior Notes due 2022 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Senior note, interest rate	4.00%			4.00%
Repayments of Debt				$ 78,671,000
WES Operating [Member] | RCF [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility, expandable maximum borrowing capacity	$ 2,500,000,000			2,500,000,000
Facility, maximum borrowing capacity	2,000,000,000			2,000,000,000
Facility, outstanding borrowings	220,000,000			220,000,000
Facility, outstanding letters of credit	5,100,000			5,100,000
Facility, available borrowing capacity	$ 1,800,000,000			$ 1,800,000,000
Facility, interest rate at period end	1.58%	1.65%		1.58%	1.65%
Facility, fee rate				0.25%	0.25%
Facility, repayment of borrowings				$ 180,000,000
WES Operating [Member] | RCF [Member] | Revolving Credit Facility [Member] | Non-Extending Lender [Member]
Debt Instrument [Line Items]
Facility, borrowing capacity for non-extending lender	$ 100,000,000			$ 100,000,000
WES Operating [Member] | Term Loan Facility [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Gain (loss) on early extinguishment of debt			$ (2,300,000)
Facility, repayment of borrowings			$ 3,000,000,000