Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net earnings (loss)	$ 1,992	$ 858	$ 1,213
Other comprehensive income (loss), net of tax
Foreign currency translation	(8)	(16)	(60)
Gain (loss) on cash flow hedges	(18)	(30)	(10)
Pension and postretirement benefits	(2)	(7)	0
Total other comprehensive income (loss), net of tax	(28)	(53)	(70)
Total comprehensive income (loss), net of tax	1,964	805	1,143
Comprehensive (income) loss attributable to noncontrolling interests	(7)	(6)	(6)
Comprehensive income (loss) attributable to Celanese Corporation	$ 1,957	$ 799	$ 1,137