Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (35)	$ 185
Pension and other post-retirement benefits liability
Pension and other post-retirement benefits reserves adjustment	0	1
Foreign currency translation adjustments
Foreign currency translation	6	(33)
Income tax (provision) benefit on foreign currency translation	8	(4)
Other comprehensive income (loss), net of income taxes	14	(36)
Comprehensive income (loss)	(21)	149
Comprehensive income attributable to noncontrolling interests, net of tax provision of $1 and $1 for the three months ended March 31, 2025 and 2024, respectively	5	9
Comprehensive income (loss) attributable to Westlake Corporation	$ (26)	$ 140