Earnings and Dividends per Share (Schedule of Net Income Attributable to Common Stockholders) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Earnings and Dividends Per Share [Abstract]
Net income attributable to Westlake Chemical Corporation	$ 394	$ 756
Net income attributable to participating securities	(2)	(4)
Net income attributable to common shareholders	$ 392	$ 752