Debt and Interest Expense - Debt Outstanding Table (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Finance leases - short-term debt	$ 3,794	$ 8,264
Total short-term debt, principal	506,040	439,345
Total short-term debt, carrying value	505,932	438,870
Finance leases - long-term debt	1,533	23,644
Total long-term debt, carrying value	6,400,616	7,415,832
Valuation, Market Approach [Member] \| Level-2 Inputs [Member]
Debt Instrument [Line Items]
Short-term debt, fair value	508,947	444,505
Long-Term Debt Obligations [Member]
Debt Instrument [Line Items]
Total long-term debt, principal	6,470,182	7,494,539
Total long-term debt, carrying value	6,400,616	7,415,832
Long-Term Debt Obligations [Member] \| Valuation, Market Approach [Member] \| Level-2 Inputs [Member]
Debt Instrument [Line Items]
Long-term debt, fair value	7,284,665	7,845,524
WES Operating [Member]
Debt Instrument [Line Items]
Total short-term debt, carrying value	505,932	438,870
Total long-term debt, carrying value	6,400,616	7,415,832
WES Operating [Member] \| Finance Lease Liability, Short Term [Member]
Debt Instrument [Line Items]
Finance leases - short-term debt	3,794	8,264
WES Operating [Member] \| Finance Lease Liability, Short Term [Member] \| Valuation, Market Approach [Member] \| Level-2 Inputs [Member]
Debt Instrument [Line Items]
Finance leases - short-term debt	3,794	8,264
WES Operating [Member] \| Finance Lease Liability, Long Term [Member]
Debt Instrument [Line Items]
Finance leases - long-term debt	1,533	23,644
WES Operating [Member] \| Finance Lease Liability, Long Term [Member] \| Valuation, Market Approach [Member] \| Level-2 Inputs [Member]
Debt Instrument [Line Items]
Finance leases - long-term debt	$ 1,533	23,644
WES Operating [Member] \| Senior Notes [Member] \| 4.000% Senior Notes due 2022 [Member]
Debt Instrument [Line Items]
Senior note, interest rate	4.00%
Principal	$ 502,246	580,917
Short-term debt, carrying value	502,138
Long-term debt, carrying value		580,555
WES Operating [Member] \| Senior Notes [Member] \| 4.000% Senior Notes due 2022 [Member] \| Valuation, Market Approach [Member] \| Level-2 Inputs [Member]
Debt Instrument [Line Items]
Short-term debt, fair value	$ 505,153
Long-term debt, fair value		597,568
WES Operating [Member] \| Senior Notes [Member] \| 5.375% Senior Notes due 2021 [Member]
Debt Instrument [Line Items]
Senior note, interest rate	5.375%
Principal	$ 0	431,081
Short-term debt, carrying value	0	430,606
WES Operating [Member] \| Senior Notes [Member] \| 5.375% Senior Notes due 2021 [Member] \| Valuation, Market Approach [Member] \| Level-2 Inputs [Member]
Debt Instrument [Line Items]
Short-term debt, fair value	0	436,241
WES Operating [Member] \| Senior Notes [Member] \| Floating-Rate Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Principal	213,138	239,978
Long-term debt, carrying value	212,642	238,879
WES Operating [Member] \| Senior Notes [Member] \| Floating-Rate Senior Notes due 2023 [Member] \| Valuation, Market Approach [Member] \| Level-2 Inputs [Member]
Debt Instrument [Line Items]
Long-term debt, fair value	$ 213,072	235,066
WES Operating [Member] \| Senior Notes [Member] \| 3.100% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Senior note, interest rate	3.10%
Principal	$ 732,106	1,000,000
Long-term debt, carrying value	728,096	992,900
WES Operating [Member] \| Senior Notes [Member] \| 3.100% Senior Notes due 2025 [Member] \| Valuation, Market Approach [Member] \| Level-2 Inputs [Member]
Debt Instrument [Line Items]
Long-term debt, fair value	$ 764,815	1,028,614
WES Operating [Member] \| Senior Notes [Member] \| 3.950% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Senior note, interest rate	3.95%
Principal	$ 399,163	500,000
Long-term debt, carrying value	395,928	494,866
WES Operating [Member] \| Senior Notes [Member] \| 3.950% Senior Notes due 2025 [Member] \| Valuation, Market Approach [Member] \| Level-2 Inputs [Member]
Debt Instrument [Line Items]
Long-term debt, fair value	$ 418,506	512,807
WES Operating [Member] \| Senior Notes [Member] \| 4.650% Senior Notes due 2026 [Member]
Debt Instrument [Line Items]
Senior note, interest rate	4.65%
Principal	$ 474,242	500,000
Long-term debt, carrying value	471,629	496,708
WES Operating [Member] \| Senior Notes [Member] \| 4.650% Senior Notes due 2026 [Member] \| Valuation, Market Approach [Member] \| Level-2 Inputs [Member]
Debt Instrument [Line Items]
Long-term debt, fair value	$ 516,473	524,880
WES Operating [Member] \| Senior Notes [Member] \| 4.500% Senior Notes due 2028 [Member]
Debt Instrument [Line Items]
Senior note, interest rate	4.50%
Principal	$ 400,000	400,000
Long-term debt, carrying value	396,145	395,617
WES Operating [Member] \| Senior Notes [Member] \| 4.500% Senior Notes due 2028 [Member] \| Valuation, Market Approach [Member] \| Level-2 Inputs [Member]
Debt Instrument [Line Items]
Long-term debt, fair value	$ 437,673	415,454
WES Operating [Member] \| Senior Notes [Member] \| 4.750% Senior Notes due 2028 [Member]
Debt Instrument [Line Items]
Senior note, interest rate	4.75%
Principal	$ 400,000	400,000
Long-term debt, carrying value	396,938	396,555
WES Operating [Member] \| Senior Notes [Member] \| 4.750% Senior Notes due 2028 [Member] \| Valuation, Market Approach [Member] \| Level-2 Inputs [Member]
Debt Instrument [Line Items]
Long-term debt, fair value	$ 444,550	418,786
WES Operating [Member] \| Senior Notes [Member] \| 4.050% Senior Notes due 2030 [Member]
Debt Instrument [Line Items]
Senior note, interest rate	4.05%
Principal	$ 1,200,000	1,200,000
Long-term debt, carrying value	1,190,339	1,189,407
WES Operating [Member] \| Senior Notes [Member] \| 4.050% Senior Notes due 2030 [Member] \| Valuation, Market Approach [Member] \| Level-2 Inputs [Member]
Debt Instrument [Line Items]
Long-term debt, fair value	$ 1,323,595	1,342,996
WES Operating [Member] \| Senior Notes [Member] \| 5.450% Senior Notes due 2044 [Member]
Debt Instrument [Line Items]
Senior note, interest rate	5.45%
Principal	$ 600,000	600,000
Long-term debt, carrying value	593,733	593,598
WES Operating [Member] \| Senior Notes [Member] \| 5.450% Senior Notes due 2044 [Member] \| Valuation, Market Approach [Member] \| Level-2 Inputs [Member]
Debt Instrument [Line Items]
Long-term debt, fair value	$ 717,804	607,234
WES Operating [Member] \| Senior Notes [Member] \| 5.300% Senior Notes due 2048 [Member]
Debt Instrument [Line Items]
Senior note, interest rate	5.30%
Principal	$ 700,000	700,000
Long-term debt, carrying value	687,265	687,048
WES Operating [Member] \| Senior Notes [Member] \| 5.300% Senior Notes due 2048 [Member] \| Valuation, Market Approach [Member] \| Level-2 Inputs [Member]
Debt Instrument [Line Items]
Long-term debt, fair value	$ 844,223	694,172
WES Operating [Member] \| Senior Notes [Member] \| 5.500% Senior Notes due 2048 [Member]
Debt Instrument [Line Items]
Senior note, interest rate	5.50%
Principal	$ 350,000	350,000
Long-term debt, carrying value	342,659	342,543
WES Operating [Member] \| Senior Notes [Member] \| 5.500% Senior Notes due 2048 [Member] \| Valuation, Market Approach [Member] \| Level-2 Inputs [Member]
Debt Instrument [Line Items]
Long-term debt, fair value	$ 418,907	343,928
WES Operating [Member] \| Senior Notes [Member] \| 5.250% Senior Notes due 2050 [Member]
Debt Instrument [Line Items]
Senior note, interest rate	5.25%
Principal	$ 1,000,000	1,000,000
Long-term debt, carrying value	983,709	983,512
WES Operating [Member] \| Senior Notes [Member] \| 5.250% Senior Notes due 2050 [Member] \| Valuation, Market Approach [Member] \| Level-2 Inputs [Member]
Debt Instrument [Line Items]
Long-term debt, fair value	$ 1,183,514	$ 1,100,375

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=123466204&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

+ Details

Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=124435984&loc=d3e28551-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124429444&loc=SL124452920-239629

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69C
-URI http://asc.fasb.org/extlink&oid=123466577&loc=SL123495737-112612

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69B
-URI http://asc.fasb.org/extlink&oid=123466577&loc=SL123495735-112612

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Present value of lessee's discounted obligation for lease payments from finance lease, classified as current.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123391704&loc=SL77918627-209977

+ Details

Name:	us-gaap_FinanceLeaseLiabilityCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Present value of lessee's discounted obligation for lease payments from finance lease, classified as noncurrent.

+ References

+ Details

Name:	us-gaap_FinanceLeaseLiabilityNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt and lease obligation, classified as noncurrent.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebtAndCapitalLeaseObligations
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt and lease obligation, classified as current.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19,20)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebtCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermDebtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebtNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents the amount of short-term debt existing as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_ShorttermDebtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of current portion of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

No definition available.

+ Details

Name:	wes_DebtInstrumentCarryingAmountCurrent
Namespace Prefix:	wes_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_ValuationTechniqueAxis=us-gaap_MarketApproachValuationTechniqueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=wes_LongTermDebtObligationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=wes_WesternMidstreamOperatingLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wes_FinanceLeaseLiabilityShortTermMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wes_FinanceLeaseLiabilityLongTermMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wes_SeniorNotes4PercentDue2022Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wes_SeniorNotes5Point375PercentDue2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wes_SeniorNotesFloatingRateDue2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wes_SeniorNotes3Point100PercentDue2025Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wes_SeniorNotes3Point950PercentDue2025Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wes_SeniorNotes4Point650PercentDue2026Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wes_SeniorNotes4Point500PercentDue2028Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wes_SeniorNotes4Point750PercentDue2028Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wes_SeniorNotes4Point50PercentDue2030Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wes_SeniorNotes5Point450PercentDue2044Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wes_SeniorNotes5Point300PercentDue2048Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wes_SeniorNotes5Point500PercentDue2048Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wes_SeniorNotes5Point250PercentDue2050Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: