Earnings (Loss) Per Share (Schedule of Earnings (Loss) Per Share) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Amounts attributable to Celanese Corporation
Earnings (loss) from continuing operations	$ 230	$ 265	$ 652	$ 742
Earnings (loss) from discontinued operations	(4)	(3)	(12)	(2)
Net earnings (loss)	$ 226	$ 262	$ 640	$ 740
Weighted average shares - basic	136,579,077	144,005,098	138,599,330	145,959,821
Incremental shares attributable to equity awards	372,846	596,367	388,991	625,739
Weighted average shares - diluted	136,951,923	144,601,465	138,988,321	146,585,560