Earnings (Loss) Per Share (Schedule of Earnings (Loss) Per Share) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Amounts attributable to Celanese Corporation
Earnings (loss) from continuing operations	$ 268	$ 407	$ 816	$ 1,116
Earnings (loss) from discontinued operations	(5)	(6)	(7)	(8)
Net earnings (loss)	$ 263	$ 401	$ 809	$ 1,108
Weighted average shares - basic	122,699,859	134,519,301	125,159,647	135,336,704
Incremental shares attributable to equity awards	599,805	980,089	709,182	1,050,999
Weighted average shares - diluted	123,299,664	135,499,390	125,868,829	136,387,703

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