Consolidated Statements Of Operations - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Net sales	$ 11,778	$ 7,504	$ 8,118
Cost of sales	8,283	6,481	6,858
Gross profit	3,495	1,023	1,260
Selling, general and administrative expenses	551	449	458
Amortization of intangibles	123	109	109
Restructuring, transaction and integration-related costs	21	36	37
Income from operations	2,800	429	656
Other income (expense)
Interest expense	(176)	(142)	(124)
Other income, net	53	44	38
Income before income taxes	2,677	331	570
Provision for (benefit from) income taxes	607	(42)	108
Net income	2,070	373	462
Net income attributable to noncontrolling interests	55	43	41
Net income attributable to Westlake Corporation	$ 2,015	$ 330	$ 421
Earnings per common share attributable to Westlake Corporation:
Basic (in dollars per share)	$ 15.66	$ 2.57	$ 3.26
Diluted (in dollars per share)	$ 15.58	$ 2.56	$ 3.25
Weighted average common shares outstanding:
Basic (in shares)	128,002,911	127,850,592	128,395,184
Diluted (in shares)	128,697,982	128,089,058	128,757,293