Consolidating Guarantor Financial Information (Schedule of Consolidating Statements of Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Condensed Financial Statements, Captions [Line Items]
Net earnings (loss)	$ 220	$ 338
Foreign currency translation gain (loss)	(2)	7
Gain (loss) on cash flow hedges	(39)	(3)
Total other comprehensive income (loss), net of tax	(41)	4
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	179	342
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	(2)	(1)
Comprehensive income (loss) attributable to Celanese Corporation	177	341
Parent Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Net earnings (loss)	218	337
Foreign currency translation gain (loss)	(2)	7
Gain (loss) on cash flow hedges	(39)	(3)
Total other comprehensive income (loss), net of tax	(41)	4
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	177	341
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	0	0
Comprehensive income (loss) attributable to Celanese Corporation	177	341
Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Net earnings (loss)	226	337
Foreign currency translation gain (loss)	(2)	7
Gain (loss) on cash flow hedges	(39)	(3)
Total other comprehensive income (loss), net of tax	(41)	4
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	185	341
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	0	0
Comprehensive income (loss) attributable to Celanese Corporation	185	341
Subsidiary Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net earnings (loss)	225	311
Foreign currency translation gain (loss)	(44)	(18)
Gain (loss) on cash flow hedges	(1)	6
Total other comprehensive income (loss), net of tax	(45)	(12)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	180	299
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	0	0
Comprehensive income (loss) attributable to Celanese Corporation	180	299
Non-Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net earnings (loss)	189	245
Foreign currency translation gain (loss)	(54)	(24)
Gain (loss) on cash flow hedges	0	8
Total other comprehensive income (loss), net of tax	(54)	(16)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	135	229
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	(2)	(1)
Comprehensive income (loss) attributable to Celanese Corporation	133	228
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net earnings (loss)	(638)	(892)
Foreign currency translation gain (loss)	100	35
Gain (loss) on cash flow hedges	40	(11)
Total other comprehensive income (loss), net of tax	140	24
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	(498)	(868)
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	0	0
Comprehensive income (loss) attributable to Celanese Corporation	$ (498)	$ (868)