Consolidating Guarantor Financial Information (Schedule of Consolidating Statements of Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Net earnings (loss)	$ 365	$ 184
Other comprehensive income (loss), net of tax
Foreign currency translation	49	28
Gain (loss) on cash flow hedges	(1)	(2)
Pension and postretirement benefits	1	5
Total other comprehensive income (loss), net of tax	49	31
Total comprehensive income (loss), net of tax	414	215
Comprehensive (income) loss attributable to noncontrolling interests	(2)	(1)
Comprehensive income (loss) attributable to Celanese Corporation	412	214
Parent Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Net earnings (loss)	363	183
Other comprehensive income (loss), net of tax
Foreign currency translation	49	28
Gain (loss) on cash flow hedges	(1)	(2)
Pension and postretirement benefits	1	5
Total other comprehensive income (loss), net of tax	49	31
Total comprehensive income (loss), net of tax	412	214
Comprehensive (income) loss attributable to noncontrolling interests	0	0
Comprehensive income (loss) attributable to Celanese Corporation	412	214
Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Net earnings (loss)	363	183
Other comprehensive income (loss), net of tax
Foreign currency translation	49	28
Gain (loss) on cash flow hedges	(1)	(2)
Pension and postretirement benefits	1	5
Total other comprehensive income (loss), net of tax	49	31
Total comprehensive income (loss), net of tax	412	214
Comprehensive (income) loss attributable to noncontrolling interests	0	0
Comprehensive income (loss) attributable to Celanese Corporation	412	214
Subsidiary Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net earnings (loss)	291	130
Other comprehensive income (loss), net of tax
Foreign currency translation	63	30
Gain (loss) on cash flow hedges	(1)	(2)
Pension and postretirement benefits	1	4
Total other comprehensive income (loss), net of tax	63	32
Total comprehensive income (loss), net of tax	354	162
Comprehensive (income) loss attributable to noncontrolling interests	0	0
Comprehensive income (loss) attributable to Celanese Corporation	354	162
Non-Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net earnings (loss)	330	150
Other comprehensive income (loss), net of tax
Foreign currency translation	74	39
Gain (loss) on cash flow hedges	(1)	(2)
Pension and postretirement benefits	1	6
Total other comprehensive income (loss), net of tax	74	43
Total comprehensive income (loss), net of tax	404	193
Comprehensive (income) loss attributable to noncontrolling interests	(2)	(1)
Comprehensive income (loss) attributable to Celanese Corporation	402	192
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net earnings (loss)	(982)	(462)
Other comprehensive income (loss), net of tax
Foreign currency translation	(186)	(97)
Gain (loss) on cash flow hedges	3	6
Pension and postretirement benefits	(3)	(15)
Total other comprehensive income (loss), net of tax	(186)	(106)
Total comprehensive income (loss), net of tax	(1,168)	(568)
Comprehensive (income) loss attributable to noncontrolling interests	0	0
Comprehensive income (loss) attributable to Celanese Corporation	$ (1,168)	$ (568)