Earnings and Dividends per Share (Schedule of Net Income Attributable to Common Stockholders) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Earnings and Dividends Per Share [Abstract]
Net income attributable to Westlake Corporation	$ 297	$ 858	$ 691	$ 1,614
Net income attributable to participating securities	(1)	(5)	(3)	(9)
Net income attributable to common shareholders	$ 296	$ 853	$ 688	$ 1,605