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Related Party and Affiliate Transactions (Details) $ in Millions, lb in Billions		12 Months Ended
	Jun. 17, 2015 lb	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Feb. 01, 2022 USD ($)
Related Party Transaction [Line Items]
Investments in joint ventures		$ 225
Dividends received from equity method investments		16	$ 15	$ 12
Related party receivable		3	3
Affiliates
Related Party Transaction [Line Items]
Plant capacity (in lbs) \| lb	2.2
Incurred and paid lease payments		3	3	3
Affiliates \| YNCORIS GmbH & Co. KG
Related Party Transaction [Line Items]
Investments in joint ventures		$ 53	57
Affiliates \| YNCORIS GmbH & Co. KG \| YNCORIS GmbH & Co. KG
Related Party Transaction [Line Items]
Ownership interest (in percent)		20.00%
Affiliates \| YNCORIS GmbH & Co. KG \| Electricity And Technical Services
Related Party Transaction [Line Items]
Purchases from related parties		$ 188	174	149
Accounts payable due to affiliate		37	43
Affiliates \| Westlake UV Coatings (Shanghai) Co., Ltd.
Related Party Transaction [Line Items]
Investments in joint ventures					$ 7
Affiliates \| Westlake UV Coatings (Shanghai) Co., Ltd. \| Westlake UV Coatings (Shanghai) Co., Ltd.
Related Party Transaction [Line Items]
Ownership interest (in percent)					49.99%
Corporate Joint Venture \| Pipeline Fees For Transport Of Natural Gas Liquid Feedstocks \| Cypress Interstate Pipeline L.L.C
Related Party Transaction [Line Items]
Purchases from related parties		$ 16	14	13
Accounts payable due to affiliate			1
Corporate Joint Venture \| Cypress Interstate Pipeline L.L.C
Related Party Transaction [Line Items]
Investments in joint ventures			7
Corporate Joint Venture \| Cypress Interstate Pipeline L.L.C \| Cypress Interstate Pipeline L.L.C
Related Party Transaction [Line Items]
Ownership interest (in percent)		50.00%
American Air Liquide Holdings, Inc. \| American Air Liquide Holdings
Related Party Transaction [Line Items]
Purchases and lease expense to related parties		$ 43	39	34
Sales to related parties		11	8	$ 7
Accounts payable due to related parties		4	3
Related party receivable		$ 2	$ 1