Earnings and Dividends per Share (Reconciliation of Denominator for Basic and Diluted Earnings Per Share) (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Earnings and Dividends Per Share [Abstract]
Weighted average common shares—basic	127,943,400	128,060,193	128,118,160	128,053,337
Weighted Average Number Diluted Shares Outstanding Adjustment	803,612	705,621	885,590	656,760
Weighted average common shares-diluted	128,747,012	128,765,814	129,003,750	128,710,097
Earnings per share attributable to Westlake Chemical Corporation: Basic (in dollars per share)	$ 3.12	$ 4.71	$ 15.65	$ 10.65
Earnings per share attributable to Westlake Chemical Corporation: Diluted (in dollars per share)	$ 3.10	$ 4.69	$ 15.54	$ 10.60