Earnings (Loss) Per Share (Schedule of Earnings (Loss) Per Share) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Amounts attributable to Celanese Corporation
Earnings (loss) from continuing operations	$ 119	$ 167	$ 512	$ 510
Earnings (loss) from discontinued operations	(2)	0	(2)	2
Net earnings (loss)	117	167	510	512
Cumulative preferred stock dividends	0	0	0	0
Net earnings (loss) available to common stockholders	$ 117	$ 167	$ 510	$ 512
Weighted average shares - basic	159,123,808	156,194,459	157,936,063	156,147,982
Dilutive stock options	292,661	1,898,195	1,054,012	1,975,911
Dilutive restricted stock units	678,435	926,185	654,091	841,918
Weighted-average shares - diluted	160,094,904	159,018,839	159,644,166	158,965,811
Per share
Earnings (loss) from continuing operations - basic	$ 0.75	$ 1.07	$ 3.24	$ 3.27
Earnings (loss) from discontinued operations - basic	$ (0.01)	$ 0.00	$ (0.01)	$ 0.01
Net earnings (loss) - basic	$ 0.74	$ 1.07	$ 3.23	$ 3.28
Earnings (loss) from continuing operations - diluted	$ 0.74	$ 1.05	$ 3.21	$ 3.21
Earnings (loss) from discontinued operations - diluted	$ (0.01)	$ 0.00	$ (0.01)	$ 0.01
Net earnings (loss) - diluted	$ 0.73	$ 1.05	$ 3.20	$ 3.22