Consolidated Statements of Operations (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Statement [Abstract]
Net sales	$ 3,207	$ 3,251	$ 6,182	$ 6,607
Cost of sales	2,543	2,609	5,052	5,173
Gross profit	664	642	1,130	1,434
Selling, general and administrative expenses	224	213	433	435
Amortization of intangibles	30	30	60	61
Restructuring, transaction and integration-related costs	4	3	8	6
Income from operations	406	396	629	932
Other income (expense)
Interest expense	(41)	(42)	(81)	(84)
Other income, net	59	23	109	45
Income before income taxes	424	377	657	893
Provision for income taxes	101	70	149	179
Net income	323	307	508	714
Net income attributable to noncontrolling interests	10	10	21	23
Net income attributable to Westlake Corporation	$ 313	$ 297	$ 487	$ 691
Earnings per common share attributable to Westlake Corporation:
Basic (in dollars per share)	$ 2.42	$ 2.32	$ 3.77	$ 5.39
Diluted (in dollars per share)	$ 2.40	$ 2.31	$ 3.75	$ 5.35
Weighted average common shares outstanding:
Basic (in shares)	128,576,735	127,649,341	128,468,359	127,599,093
Diluted (in shares)	129,350,720	128,484,016	129,185,545	128,471,760