Consolidating Guarantor Financial Information (Schedule of Consolidating Statements of Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Net earnings (loss)	$ 849	$ 906	$ 285
Other comprehensive income (loss), net of tax
Unrealized gain (loss) on marketable securities	(1)	0	0
Foreign currency translation	174	(11)	(188)
Gain (loss) on cash flow hedges	(1)	5	2
Pension and postretirement benefits	9	(4)	3
Total other comprehensive income (loss), net of tax	181	(10)	(183)
Total comprehensive income (loss), net of tax	1,030	896	102
Comprehensive (income) loss attributable to noncontrolling interests	(6)	(6)	19
Comprehensive income (loss) attributable to Celanese Corporation	1,024	890	121
Parent Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Net earnings (loss)	843	900	304
Other comprehensive income (loss), net of tax
Unrealized gain (loss) on marketable securities	(1)	0	0
Foreign currency translation	174	(11)	(188)
Gain (loss) on cash flow hedges	(1)	5	2
Pension and postretirement benefits	9	(4)	3
Total other comprehensive income (loss), net of tax	181	(10)	(183)
Total comprehensive income (loss), net of tax	1,024	890	121
Comprehensive (income) loss attributable to noncontrolling interests	0	0	0
Comprehensive income (loss) attributable to Celanese Corporation	1,024	890	121
Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Net earnings (loss)	843	898	302
Other comprehensive income (loss), net of tax
Unrealized gain (loss) on marketable securities	(1)	0	0
Foreign currency translation	174	(11)	(188)
Gain (loss) on cash flow hedges	(1)	5	2
Pension and postretirement benefits	9	(4)	3
Total other comprehensive income (loss), net of tax	181	(10)	(183)
Total comprehensive income (loss), net of tax	1,024	888	119
Comprehensive (income) loss attributable to noncontrolling interests	0	0	0
Comprehensive income (loss) attributable to Celanese Corporation	1,024	888	119
Subsidiary Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net earnings (loss)	768	855	260
Other comprehensive income (loss), net of tax
Unrealized gain (loss) on marketable securities	(1)	0	0
Foreign currency translation	226	(65)	(181)
Gain (loss) on cash flow hedges	(1)	5	5
Pension and postretirement benefits	7	(4)	3
Total other comprehensive income (loss), net of tax	231	(64)	(173)
Total comprehensive income (loss), net of tax	999	791	87
Comprehensive (income) loss attributable to noncontrolling interests	0	0	0
Comprehensive income (loss) attributable to Celanese Corporation	999	791	87
Non-Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net earnings (loss)	687	736	72
Other comprehensive income (loss), net of tax
Unrealized gain (loss) on marketable securities	(1)	0	0
Foreign currency translation	268	(73)	(231)
Gain (loss) on cash flow hedges	(1)	5	1
Pension and postretirement benefits	10	(2)	2
Total other comprehensive income (loss), net of tax	276	(70)	(228)
Total comprehensive income (loss), net of tax	963	666	(156)
Comprehensive (income) loss attributable to noncontrolling interests	(6)	(6)	19
Comprehensive income (loss) attributable to Celanese Corporation	957	660	(137)
Consolidation Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net earnings (loss)	(2,292)	(2,483)	(653)
Other comprehensive income (loss), net of tax
Unrealized gain (loss) on marketable securities	3	0	0
Foreign currency translation	(668)	149	600
Gain (loss) on cash flow hedges	3	(15)	(8)
Pension and postretirement benefits	(26)	10	(8)
Total other comprehensive income (loss), net of tax	(688)	144	584
Total comprehensive income (loss), net of tax	(2,980)	(2,339)	(69)
Comprehensive (income) loss attributable to noncontrolling interests	0	0	0
Comprehensive income (loss) attributable to Celanese Corporation	$ (2,980)	$ (2,339)	$ (69)