Earnings (Loss) Per Share (Schedule of Earnings (Loss) Per Share) (Details) (USD $) In Millions, except Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Amounts attributable to Celanese Corporation
Earnings (loss) from continuing operations	$ 167	$ 147	$ 510	$ 323
Earnings (loss) from discontinued operations	0	(2)	2	(4)
Net earnings (loss)	167	145	512	319
Cumulative preferred stock dividends	0	0	0	(3)
Net earnings (loss) available to common shareholders	167	145	512	316
Net earnings (loss) available to common shareholders, diluted	$ 167	$ 145	$ 512	$ 319
Weighted average shares - basic	156,194,459	155,859,508	156,147,982	154,173,120
Dilutive stock options	1,898,195	1,670,850	1,975,911	1,793,318
Dilutive restricted stock units	926,185	353,190	841,918	364,374
Assumed conversion of preferred stock	0	0	0	2,077,591
Weighted-average shares - diluted	159,018,839	157,883,548	158,965,811	158,408,403
Per share
Earnings (loss) from continuing operations - basic	$ 1.07	$ 0.94	$ 3.27	$ 2.08
Earnings (loss) from discontinued operations - basic	$ 0.00	$ (0.01)	$ 0.01	$ (0.03)
Net earnings (loss) - basic	$ 1.07	$ 0.93	$ 3.28	$ 2.05
Earnings (loss) from continuing operations - diluted	$ 1.05	$ 0.93	$ 3.21	$ 2.04
Earnings (loss) from discontinued operations - diluted	$ 0.00	$ (0.01)	$ 0.01	$ (0.03)
Net earnings (loss) - diluted	$ 1.05	$ 0.92	$ 3.22	$ 2.01