Earnings (Loss) Per Share (Schedule of Earnings (Loss) Per Share) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Amounts attributable to Celanese Corporation
Earnings (loss) from continuing operations	$ 338	$ 365
Earnings (loss) from discontinued operations	(1)	(2)
Net earnings (loss)	$ 337	$ 363
Weighted average shares - basic	127,542,328	135,916,446
Incremental shares attributable to equity awards	673,372	467,289
Weighted average shares - diluted	128,215,700	136,383,735

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