Equity Method Investments (Changes in Investment) (Details) - LACC, LLC - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Mar. 15, 2022	Nov. 12, 2019
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Balance at beginning of period	$ 943	$ 961
Cash contributions	87	22
Additional interest purchased	89
Additional interest purchased			$ 89	$ 817
Depreciation and amortization	(44)	(40)
Balance at end of period	$ 1,075	$ 943

Value of the investment at close of period. For investment in and advances to affiliates, if operations of any controlled companies are different in character from those of the company, group such affiliates within divisions and by type of activities.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 6
-Subparagraph (SX 210.12-14(3))
-URI https://asc.fasb.org/extlink&oid=122147990&loc=d3e611322-123010

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 6
-Subparagraph (SX 210.12-14(2))
-URI https://asc.fasb.org/extlink&oid=122147990&loc=d3e611322-123010

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 6
-Subparagraph (SX 210.12-14(Column E))
-URI https://asc.fasb.org/extlink&oid=122147990&loc=d3e611322-123010

+ Details

Name:	us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Gross additions to the investment in and advance to the affiliate.

+ References

+ Details

Name:	us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValueGrossAdditions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Gross reductions to the investment in and advance to the affiliate.

+ References

+ Details

Name:	us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValueGrossReductions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of increase (decrease) in the investments in and advances to affiliates.

+ References

+ Details

Name:	us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValuePeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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

- Definition

This element represents the cost of additional investments for under the equity method of accounting.

+ References

No definition available.

+ Details

Name:	wlk_IncreaseinEquityMethodInvestment
Namespace Prefix:	wlk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=wlk_LACCLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: