Unaudited Interim Consolidated Statement Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]
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				(4)
Purchases of treasury stock, shares	(1,831,970)	(1,831,970)	1,831,970
Purchases of treasury stock, including related fees	$ (250)	$ 0	$ (250)
Stock awards, shares		296,090
Stock awards		$ 0
Net earnings (loss) attributable to Celanese Corporation	322				322
Common stock dividends					(78)
Other comprehensive income (loss), net of tax	26					26
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	1						1
Distributions to noncontrolling interests							(5)
Balance as of the end of the period, noncontrolling interest at Mar. 31, 2021							365
Balance as of the end of the period, shares at Mar. 31, 2021		112,632,584	57,066,485
Balance as of the end of the period at Mar. 31, 2021	3,907
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Celanese Corporation stockholders' equity	3,542	$ 0	$ (4,744)	253	8,335	(302)
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				(7)
Purchases of treasury stock, shares	0	0	0
Purchases of treasury stock, including related fees	$ 0	$ 0	$ 0
Stock awards, shares		283,606
Stock awards		$ 0
Net earnings (loss) attributable to Celanese Corporation	502				502
Common stock dividends					(73)
Other comprehensive income (loss), net of tax	(4)					(4)
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	2						2
Distributions to noncontrolling interests							(4)
Balance as of the end of the period, noncontrolling interest at Mar. 31, 2022	346						$ 346
Balance as of the end of the period, shares at Mar. 31, 2022		108,307,341	61,736,289
Balance as of the end of the period at Mar. 31, 2022	4,953
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Celanese Corporation stockholders' equity	$ 4,607	$ 0	$ (5,492)	$ 326	$ 10,106	$ (333)