Unaudited Interim Consolidated Statement Equity - USD ($) $ in Millions	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss), Net	Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Celanese Corporation stockholders' equity		$ 0	$ (4,494)	$ 257	$ 8,091	$ (328)
Balance as of the beginning of the period (in shares) at Dec. 31, 2020		114,168,464	55,234,515
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation, net of tax				56
Purchases of treasury stock (in shares)	(5,332,727)	(5,332,727)	5,332,727
Purchases of treasury stock, including related fees	$ (800)	$ 0	$ (800)
Issuance of treasury stock under stock plans (in shares)			(27,186)
Issuance of treasury stock under stock plans			$ 1
Stock awards (in shares)		344,586
Stock awards		$ 0
Net earnings (loss) attributable to Celanese Corporation	1,366				1,366
Common stock dividends					(230)
Other comprehensive income (loss), net of tax	0					0
Balance as of the beginning of the period, noncontrolling interest at Dec. 31, 2020							$ 369
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss) attributable to noncontrolling interests	4						4
Distributions to noncontrolling interests							(21)
Balance as of the end of the period, noncontrolling interest at Sep. 30, 2021							352
Balance as of the end of the period (in shares) at Sep. 30, 2021		109,180,323	60,540,056
Balance as of the end of the period at Sep. 30, 2021	4,271
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Celanese Corporation stockholders' equity		$ 0	$ (4,993)	292	8,797	(298)
Balance as of the beginning of the period (in shares) at Jun. 30, 2021		111,115,442	58,601,877
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation, net of tax				21
Purchases of treasury stock (in shares)		(1,938,179)	1,938,179
Purchases of treasury stock, including related fees		$ 0	$ (300)
Stock awards (in shares)		3,060
Stock awards		$ 0
Net earnings (loss) attributable to Celanese Corporation	506				506
Common stock dividends					(76)
Other comprehensive income (loss), net of tax	(30)					(30)
Balance as of the beginning of the period, noncontrolling interest at Jun. 30, 2021							359
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss) attributable to noncontrolling interests	1						1
Distributions to noncontrolling interests							(8)
Balance as of the end of the period, noncontrolling interest at Sep. 30, 2021							352
Balance as of the end of the period (in shares) at Sep. 30, 2021		109,180,323	60,540,056
Balance as of the end of the period at Sep. 30, 2021	4,271
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Celanese Corporation stockholders' equity	3,919	$ 0	$ (5,293)	313	9,227	(328)
Celanese Corporation stockholders' equity	4,189	$ 0	$ (5,492)	333	9,677	(329)
Balance as of the beginning of the period (in shares) at Dec. 31, 2021		108,023,735	61,736,289
Balance as of the beginning of the period at Dec. 31, 2021	$ 4,537
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation, net of tax				23
Purchases of treasury stock (in shares)	0	0	0
Purchases of treasury stock, including related fees	$ 0	$ 0	$ 0
Issuance of treasury stock under stock plans (in shares)			(32,243)
Issuance of treasury stock under stock plans			$ 0
Stock awards (in shares)		363,004
Stock awards		$ 0
Net earnings (loss) attributable to Celanese Corporation	1,127				1,127
Common stock dividends					(220)
Other comprehensive income (loss), net of tax	(169)					(169)
Balance as of the beginning of the period, noncontrolling interest at Dec. 31, 2021	348						348
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss) attributable to noncontrolling interests	6						6
Distributions to noncontrolling interests							(10)
Balance as of the end of the period, noncontrolling interest at Sep. 30, 2022	344						344
Balance as of the end of the period (in shares) at Sep. 30, 2022		108,386,739	61,704,046
Balance as of the end of the period at Sep. 30, 2022	5,294
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Celanese Corporation stockholders' equity		$ 0	$ (5,492)	344	10,466	(438)
Balance as of the beginning of the period (in shares) at Jun. 30, 2022		108,346,035	61,704,046
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation, net of tax				12
Purchases of treasury stock (in shares)		0	0
Purchases of treasury stock, including related fees		$ 0	$ 0
Stock awards (in shares)		40,704
Stock awards		$ 0
Net earnings (loss) attributable to Celanese Corporation	191				191
Common stock dividends					(73)
Other comprehensive income (loss), net of tax	(60)					(60)
Balance as of the beginning of the period, noncontrolling interest at Jun. 30, 2022							345
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss) attributable to noncontrolling interests	2						2
Distributions to noncontrolling interests							(3)
Balance as of the end of the period, noncontrolling interest at Sep. 30, 2022	344						$ 344
Balance as of the end of the period (in shares) at Sep. 30, 2022		108,386,739	61,704,046
Balance as of the end of the period at Sep. 30, 2022	5,294
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Celanese Corporation stockholders' equity	$ 4,950	$ 0	$ (5,492)	$ 356	$ 10,584	$ (498)