Earnings and Dividends per Share (Reconciliation of Denominator for Basic and Diluted Earnings Per Share) (Details) - $ / shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Earnings and Dividends Per Share [Abstract]
Weighted average common shares—basic	127,548,287	128,071,355
Weighted Average Number Diluted Shares Outstanding Adjustment	911,081	853,744
Weighted average common shares-diluted	128,459,368	128,925,099
Earnings per share attributable to Westlake Chemical Corporation: Basic (in dollars per share)	$ 3.07	$ 5.87
Earnings per share attributable to Westlake Chemical Corporation: Diluted (in dollars per share)	$ 3.05	$ 5.83