Unaudited Interim Consolidated Statement Equity - USD ($) $ in Millions	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest
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, shares at Dec. 31, 2020		114,168,464	55,234,515
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation, net of tax				35
Purchases of treasury stock, shares	(3,394,548)	(3,394,548)	3,394,548
Purchases of treasury stock, including related fees	$ (500)	$ 0	$ (500)
Issuance of treasury stock under stock plans (in shares)			(27,186)
Issuance of treasury stock under stock plans			$ 1
Stock awards, shares		341,526
Stock awards		$ 0
Net earnings (loss) attributable to Celanese Corporation	860				860
Common stock dividends					(154)
Other comprehensive income (loss), net of tax	30					30
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	3						3
Distributions to noncontrolling interests							(13)
Balance as of the end of the period, noncontrolling interest at Jun. 30, 2021							359
Balance as of the end of the period, shares at Jun. 30, 2021		111,115,442	58,601,877
Balance as of the end of the period at Jun. 30, 2021	4,157
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Celanese Corporation stockholders' equity		$ 0	$ (4,744)	253	8,335	(302)
Balance as of the beginning of the period, shares at Mar. 31, 2021		112,632,584	57,066,485
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation, net of tax				39
Purchases of treasury stock, shares		(1,562,578)	1,562,578
Purchases of treasury stock, including related fees		$ 0	$ (250)
Issuance of treasury stock under stock plans (in shares)			(27,186)
Issuance of treasury stock under stock plans			$ 1
Stock awards, shares		45,436
Stock awards		$ 0
Net earnings (loss) attributable to Celanese Corporation	538				538
Common stock dividends					(76)
Other comprehensive income (loss), net of tax	4					4
Balance as of the beginning of the period, noncontrolling interest at Mar. 31, 2021							365
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss) attributable to noncontrolling interests	2						2
Distributions to noncontrolling interests							(8)
Balance as of the end of the period, noncontrolling interest at Jun. 30, 2021							359
Balance as of the end of the period, shares at Jun. 30, 2021		111,115,442	58,601,877
Balance as of the end of the period at Jun. 30, 2021	4,157
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Celanese Corporation stockholders' equity	3,798	$ 0	$ (4,993)	292	8,797	(298)
Celanese Corporation stockholders' equity	4,189	$ 0	$ (5,492)	333	9,677	(329)
Balance as of the beginning of the period, 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				11
Purchases of treasury stock, 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, shares		322,300
Stock awards		$ 0
Net earnings (loss) attributable to Celanese Corporation	936				936
Common stock dividends					(147)
Other comprehensive income (loss), net of tax	(109)					(109)
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	4						4
Distributions to noncontrolling interests							(7)
Balance as of the end of the period, noncontrolling interest at Jun. 30, 2022	345						345
Balance as of the end of the period, shares at Jun. 30, 2022		108,346,035	61,704,046
Balance as of the end of the period at Jun. 30, 2022	5,225
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Celanese Corporation stockholders' equity		$ 0	$ (5,492)	326	10,106	(333)
Balance as of the beginning of the period, shares at Mar. 31, 2022		108,307,341	61,736,289
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation, net of tax				18
Purchases of treasury stock, shares		0	0
Purchases of treasury stock, including related fees		$ 0	$ 0
Issuance of treasury stock under stock plans (in shares)			(32,243)
Issuance of treasury stock under stock plans			$ 0
Stock awards, shares		38,694
Stock awards		$ 0
Net earnings (loss) attributable to Celanese Corporation	434				434
Common stock dividends					(74)
Other comprehensive income (loss), net of tax	(105)					(105)
Balance as of the beginning of the period, noncontrolling interest at Mar. 31, 2022							346
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 Jun. 30, 2022	345						$ 345
Balance as of the end of the period, shares at Jun. 30, 2022		108,346,035	61,704,046
Balance as of the end of the period at Jun. 30, 2022	5,225
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Celanese Corporation stockholders' equity	$ 4,880	$ 0	$ (5,492)	$ 344	$ 10,466	$ (438)