Unaudited Interim Consolidated Statement Equity - USD ($) $ in Millions	Total	Common Stock	Treasury Stock, Common	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss), Net	Noncontrolling Interests
Balance as of the beginning of the period (in shares) at Dec. 31, 2022		108,473,932	61,661,493
Balance as of the beginning of the period at Dec. 31, 2022		$ 0	$ (5,491)	$ 372	$ 11,274	$ (518)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises, shares		0
Stock option exercises		$ 0		0
Stock awards (in shares)		380,106
Stock awards		$ 0
Issuance of treasury stock under stock plans (in shares)			(50,092)
Issuance of treasury stock under stock plans			$ 1
Stock-based compensation, net of tax				14
Net earnings (loss) attributable to Celanese Corporation	$ 1,262				1,262
Common stock dividends					(228)
Other comprehensive income (loss), net of tax	(195)					(195)	$ 0
Balance as of the end of the period (in shares) at Sep. 30, 2023		108,854,038	61,611,401
Balance as of the end of the period at Sep. 30, 2023	6,491	$ 0	$ (5,490)	386	12,308	(713)
Balance as of the beginning of the period, noncontrolling interest at Dec. 31, 2022							468
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss) attributable to noncontrolling interests	1						1
Distributions/dividends to noncontrolling interests							(11)
Balance as of the end of the period, noncontrolling interest at Sep. 30, 2023							458
Balance as of the beginning of the period (in shares) at Jun. 30, 2023		108,847,435	61,611,401
Balance as of the beginning of the period at Jun. 30, 2023		$ 0	$ (5,490)	383	11,433	(702)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises, shares		0
Stock option exercises		$ 0
Stock awards (in shares)		6,603
Stock awards		$ 0
Issuance of treasury stock under stock plans (in shares)			0
Issuance of treasury stock under stock plans			$ 0
Stock-based compensation, net of tax				3
Net earnings (loss) attributable to Celanese Corporation	951				951
Common stock dividends					(76)
Other comprehensive income (loss), net of tax	(11)					(11)	0
Balance as of the end of the period (in shares) at Sep. 30, 2023		108,854,038	61,611,401
Balance as of the end of the period at Sep. 30, 2023	6,491	$ 0	$ (5,490)	386	12,308	(713)
Balance as of the beginning of the period, noncontrolling interest at Jun. 30, 2023							464
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss) attributable to noncontrolling interests	(2)						(2)
Distributions/dividends to noncontrolling interests							(4)
Balance as of the end of the period, noncontrolling interest at Sep. 30, 2023							458
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total equity	6,949
Total equity	7,552
Balance as of the beginning of the period (in shares) at Dec. 31, 2023		108,906,426	61,570,314
Balance as of the beginning of the period at Dec. 31, 2023	7,091	$ 0	$ (5,488)	394	12,929	(744)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises, shares		10,088
Stock option exercises		$ 0		1
Stock awards (in shares)		349,854
Stock awards		$ 0
Issuance of treasury stock under stock plans (in shares)			(33,068)
Issuance of treasury stock under stock plans			$ 1
Stock-based compensation, net of tax				2
Net earnings (loss) attributable to Celanese Corporation	392				392
Common stock dividends					(230)
Other comprehensive income (loss), net of tax	17					17	3
Balance as of the end of the period (in shares) at Sep. 30, 2024		109,266,368	61,537,246
Balance as of the end of the period at Sep. 30, 2024	7,274	$ 0	$ (5,487)	397	13,091	(727)
Balance as of the beginning of the period, noncontrolling interest at Dec. 31, 2023	461						461
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss) attributable to noncontrolling interests	5						5
Distributions/dividends to noncontrolling interests							(25)
Balance as of the end of the period, noncontrolling interest at Sep. 30, 2024	444						444
Balance as of the beginning of the period (in shares) at Jun. 30, 2024		109,262,563	61,537,246
Balance as of the beginning of the period at Jun. 30, 2024		$ 0	$ (5,487)	394	13,051	(792)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock option exercises, shares		849
Stock option exercises		$ 0
Stock awards (in shares)		2,956
Stock awards		$ 0
Issuance of treasury stock under stock plans (in shares)			0
Issuance of treasury stock under stock plans			$ 0
Stock-based compensation, net of tax				3
Net earnings (loss) attributable to Celanese Corporation	116				116
Common stock dividends					(76)
Other comprehensive income (loss), net of tax	65					65	4
Balance as of the end of the period (in shares) at Sep. 30, 2024		109,266,368	61,537,246
Balance as of the end of the period at Sep. 30, 2024	7,274	$ 0	$ (5,487)	$ 397	$ 13,091	$ (727)
Balance as of the beginning of the period, noncontrolling interest at Jun. 30, 2024							443
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss) attributable to noncontrolling interests	4						4
Distributions/dividends to noncontrolling interests							(7)
Balance as of the end of the period, noncontrolling interest at Sep. 30, 2024	444						$ 444
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total equity	$ 7,718