Earnings (Loss) Per Share - Schedule of Earnings (Loss) Per Share (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Amounts attributable to Celanese Corporation
Earnings (loss) from continuing operations		$ 118	$ 952	$ 395	$ 1,265
Earnings (loss) from discontinued operations		(2)	(1)	(3)	(3)
Net earnings (loss)		$ 116	$ 951	$ 392	$ 1,262
Weighted average shares - basic (in shares)		109,338,977	108,918,986	109,241,174	108,814,288
Incremental shares attributable to equity awards(1)	[1]	196,060	520,500	276,125	523,752
Weighted average shares - diluted		109,535,037	109,439,486	109,517,299	109,338,040

[1] Excludes stock options to purchase 293,045 and 219,963 shares of Common Stock for the three months ended September 30, 2024 and 2023, respectively; and 19 and 0 equity award shares for the three months ended September 30, 2024 and 2023, respectively, as their effect would have been antidilutive. Excludes stock options to purchase 149,643 and 190,651 shares of Common Stock for the nine months ended September 30, 2024 and 2023, respectively; and 74 and 42,998 equity award shares for the nine months ended September 30, 2024 and 2023, respectively, as their effect would have been antidilutive.