Consolidated Statements of Operations (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Income Statement [Abstract]
Net sales	$ 2,953	$ 3,207	$ 5,799	$ 6,182
Cost of sales	2,695	2,543	5,309	5,052
Gross profit	258	664	490	1,130
Selling, general and administrative expenses	221	224	448	433
Amortization of intangibles	31	30	61	60
Restructuring, transaction and integration-related costs	115	4	122	8
Income (loss) from operations	(109)	406	(141)	629
Other income (expense)
Interest expense	(40)	(41)	(79)	(81)
Other income, net	24	59	61	109
Income (loss) before income taxes	(125)	424	(159)	657
Provision for income taxes	6	101	7	149
Net income (loss)	(131)	323	(166)	508
Net income attributable to noncontrolling interests	11	10	16	21
Net income (loss) attributable to Westlake Corporation	$ (142)	$ 313	$ (182)	$ 487
Earnings (loss) per common share attributable to Westlake Corporation:
Basic (in dollars per share)	$ (1.11)	$ 2.42	$ (1.42)	$ 3.77
Diluted (in dollars per share)	$ (1.11)	$ 2.40	$ (1.42)	$ 3.75
Weighted average common shares outstanding:
Basic (in shares)	128,238,514	128,576,735	128,273,332	128,468,359
Diluted (in shares)	128,238,514	129,350,720	128,273,332	129,185,545