Earnings and Dividends per Share (Schedule of Net Income Attributable to Common Stockholders) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Earnings and Dividends Per Share [Abstract]
Net income attributable to Westlake Chemical Corporation	$ 401	$ 607	$ 2,015	$ 1,371
Net income attributable to participating securities	(2)	(3)	(10)	(7)
Net income attributable to common shareholders	$ 399	$ 604	$ 2,005	$ 1,364