Earnings (Loss) Per Share (Schedule of Earnings (Loss) Per Share) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Amounts attributable to Celanese Corporation
Earnings (loss) from continuing operations	$ 210	$ 344	$ 548	$ 709
Earnings (loss) from discontinued operations	(1)	0	(2)	(2)
Net earnings (loss)	$ 209	$ 344	$ 546	$ 707
Weighted average shares - basic	125,289,967	135,589,717	126,409,926	135,752,179
Incremental shares attributable to equity awards	557,927	719,441	701,120	747,569
Weighted average shares - diluted	125,847,894	136,309,158	127,111,046	136,499,748

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