Earnings and Dividends per Share (Schedule Of Net Income Attributable To Common Stockholders) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Earnings and Dividends Per Share [Abstract]
Net income (loss) attributable to Westlake Corporation	$ (1,508)	$ 602	$ 479
Net income attributable to participating securities	(7)	3	3
Net income attributable to common shareholders	$ (1,501)	$ 599	$ 476

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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