Unaudited Interim Consolidated Statement of Operations - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Income Statement [Abstract]
Net sales	$ 2,556	$ 2,419	$ 7,645	$ 7,340
Cost of sales	(2,017)	(1,898)	(6,020)	(5,811)
Gross profit	539	521	1,625	1,529
Selling, general and administrative expenses	(248)	(231)	(725)	(676)
Amortization of intangible assets	(40)	(42)	(119)	(124)
Research and development expenses	(29)	(31)	(86)	(93)
Other (charges) gains, net	(32)	(1,491)	(83)	(1,542)
Foreign exchange gain (loss), net	12	2	34	29
Gain (loss) on disposition of business and assets, net	(4)	(3)	42	(2)
Operating profit (loss)	198	(1,275)	688	(879)
Equity in net earnings (loss) of affiliates	9	39	55	90
Non-operating pension and other postretirement employee benefit (expense) income	5	2	15	5
Interest expense	(175)	(177)	(544)	(524)
Refinancing expense	0	0	0	32
Interest income	6	7	25	18
Dividend income - equity investments	44	40	88	82
Other income (expense), net	6	4	(10)	7
Earnings (loss) from continuing operations before tax	93	(1,360)	317	(1,233)
Income tax (provision) benefit	(14)	7	(58)	75
Earnings (loss) from continuing operations	79	(1,353)	259	(1,158)
Earnings (loss) from operation of discontinued operations	(2)	0	(5)	(16)
Income tax (provision) benefit from discontinued operations	1	0	1	1
Earnings (loss) from discontinued operations	(1)	0	(4)	(15)
Net earnings (loss)	78	(1,353)	255	(1,173)
Net (earnings) loss attributable to noncontrolling interests	(4)	(4)	(12)	(11)
Net earnings (loss) attributable to Celanese Corporation	74	(1,357)	243	(1,184)
Amounts attributable to Celanese Corporation
Earnings (loss) from continuing operations	75	(1,357)	247	(1,169)
Earnings (loss) from discontinued operations	(1)	0	(4)	(15)
Net earnings (loss)	$ 74	$ (1,357)	$ 243	$ (1,184)
Earnings (loss) per common share - basic
Continuing operations - basic (in dollars per share)	$ 0.68	$ (12.39)	$ 2.25	$ (10.68)
Discontinued operations - basic (in dollars per share)	(0.01)	0	(0.04)	(0.13)
Net earnings (loss) - basic (in dollars per share)	0.67	(12.39)	2.21	(10.81)
Earnings (loss) per common share - diluted
Continuing operations - diluted (in dollars per share)	0.68	(12.39)	2.24	(10.68)
Discontinued operations - diluted (in dollars per share)	(0.01)	0	(0.03)	(0.13)
Net earnings (loss) - diluted (in dollars per share)	$ 0.67	$ (12.39)	$ 2.21	$ (10.81)
Weighted average shares - basic (in shares)	109,820,213	109,565,996	109,753,986	109,504,912
Weighted average shares - diluted (in shares)	110,200,834	109,565,996	110,132,694	109,504,912