Consolidating Guarantor Financial Information (Schedule of Consolidating Statements of Operations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 6,140	$ 5,389	$ 5,674
Cost of sales	(4,625)	(3,984)	(4,356)
Gross profit	1,515	1,405	1,318
Selling, general and administrative expenses	(456)	(416)	(506)
Amortization of intangible assets	(20)	(9)	(11)
Research and development expenses	(72)	(78)	(119)
Other (charges) gains, net	(60)	(11)	(351)
Foreign exchange gain (loss), net	(1)	(1)	4
Gain (loss) on disposition of businesses and assets, net	(5)	3	(9)
Operating profit (loss)	901	893	326
Equity in net earnings (loss) of affiliates	183	155	181
Interest expense	(122)	(120)	(119)
Refinancing expense	0	(6)	0
Interest income	2	2	1
Dividend income - cost investments	108	108	107
Other income (expense), net	3	(2)	(8)
Earnings (loss) from continuing operations before tax	1,075	1,030	488
Income tax (provision) benefit	(213)	(122)	(201)
Earnings (loss) from continuing operations	862	908	287
Earnings (loss) from operation of discontinued operations	(16)	(3)	(3)
Gain (loss) on disposition of discontinued operations	0	0	0
Income tax (provision) benefit from discontinued operations	3	1	1
Earnings (loss) from discontinued operations	(13)	(2)	(2)
Net earnings (loss)	849	906	285
Net (earnings) loss attributable to noncontrolling interests	(6)	(6)	19
Net earnings (loss) attributable to Celanese Corporation	843	900	304
Parent Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	0	0	0
Cost of sales	0	0	0
Gross profit	0	0	0
Selling, general and administrative expenses	0	0	0
Amortization of intangible assets	0	0	0
Research and development expenses	0	0	0
Other (charges) gains, net	0	0	0
Foreign exchange gain (loss), net	0	0	0
Gain (loss) on disposition of businesses and assets, net	0	0	0
Operating profit (loss)	0	0	0
Equity in net earnings (loss) of affiliates	843	898	302
Interest expense	0	0	0
Refinancing expense	0	0	0
Interest income	0	0	0
Dividend income - cost investments	0	0	0
Other income (expense), net	0	0	0
Earnings (loss) from continuing operations before tax	843	898	302
Income tax (provision) benefit	0	2	2
Earnings (loss) from continuing operations	843	900	304
Earnings (loss) from operation of discontinued operations	0	0	0
Gain (loss) on disposition of discontinued operations	0	0	0
Income tax (provision) benefit from discontinued operations	0	0	0
Earnings (loss) from discontinued operations	0	0	0
Net earnings (loss)	843	900	304
Net (earnings) loss attributable to noncontrolling interests	0	0	0
Net earnings (loss) attributable to Celanese Corporation	843	900	304
Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	0	0	0
Cost of sales	0	0	0
Gross profit	0	0	0
Selling, general and administrative expenses	0	0	0
Amortization of intangible assets	0	0	0
Research and development expenses	0	0	0
Other (charges) gains, net	0	0	0
Foreign exchange gain (loss), net	0	0	0
Gain (loss) on disposition of businesses and assets, net	0	0	0
Operating profit (loss)	0	0	0
Equity in net earnings (loss) of affiliates	867	939	314
Interest expense	(20)	(16)	(77)
Refinancing expense	0	(4)	0
Interest income	25	12	18
Dividend income - cost investments	0	0	0
Other income (expense), net	(3)	(1)	(2)
Earnings (loss) from continuing operations before tax	869	930	253
Income tax (provision) benefit	(26)	(32)	49
Earnings (loss) from continuing operations	843	898	302
Earnings (loss) from operation of discontinued operations	0	0	0
Gain (loss) on disposition of discontinued operations	0	0	0
Income tax (provision) benefit from discontinued operations	0	0	0
Earnings (loss) from discontinued operations	0	0	0
Net earnings (loss)	843	898	302
Net (earnings) loss attributable to noncontrolling interests	0	0	0
Net earnings (loss) attributable to Celanese Corporation	843	898	302
Subsidiary Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	2,240	2,162	2,410
Cost of sales	(1,717)	(1,657)	(1,729)
Gross profit	523	505	681
Selling, general and administrative expenses	(135)	(112)	(242)
Amortization of intangible assets	(4)	(5)	(5)
Research and development expenses	(31)	(32)	(78)
Other (charges) gains, net	(7)	0	(5)
Foreign exchange gain (loss), net	0	0	0
Gain (loss) on disposition of businesses and assets, net	(8)	(8)	(6)
Operating profit (loss)	338	348	345
Equity in net earnings (loss) of affiliates	591	653	84
Interest expense	(104)	(94)	(76)
Refinancing expense	0	(2)	0
Interest income	4	4	40
Dividend income - cost investments	0	0	0
Other income (expense), net	2	1	2
Earnings (loss) from continuing operations before tax	831	910	395
Income tax (provision) benefit	(62)	(53)	(133)
Earnings (loss) from continuing operations	769	857	262
Earnings (loss) from operation of discontinued operations	(2)	(2)	(3)
Gain (loss) on disposition of discontinued operations	0	0	0
Income tax (provision) benefit from discontinued operations	1	0	1
Earnings (loss) from discontinued operations	(1)	(2)	(2)
Net earnings (loss)	768	855	260
Net (earnings) loss attributable to noncontrolling interests	0	0	0
Net earnings (loss) attributable to Celanese Corporation	768	855	260
Non-Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	5,013	4,322	4,485
Cost of sales	(4,016)	(3,428)	(3,897)
Gross profit	997	894	588
Selling, general and administrative expenses	(321)	(304)	(264)
Amortization of intangible assets	(16)	(4)	(6)
Research and development expenses	(41)	(46)	(41)
Other (charges) gains, net	(53)	(11)	(346)
Foreign exchange gain (loss), net	(1)	(1)	4
Gain (loss) on disposition of businesses and assets, net	3	17	(3)
Operating profit (loss)	568	545	(68)
Equity in net earnings (loss) of affiliates	166	146	162
Interest expense	(30)	(29)	(36)
Refinancing expense	0	0	0
Interest income	5	5	13
Dividend income - cost investments	111	107	107
Other income (expense), net	4	(2)	(8)
Earnings (loss) from continuing operations before tax	824	772	170
Income tax (provision) benefit	(125)	(36)	(98)
Earnings (loss) from continuing operations	699	736	72
Earnings (loss) from operation of discontinued operations	(14)	(1)	0
Gain (loss) on disposition of discontinued operations	0	0	0
Income tax (provision) benefit from discontinued operations	2	1	0
Earnings (loss) from discontinued operations	(12)	0	0
Net earnings (loss)	687	736	72
Net (earnings) loss attributable to noncontrolling interests	(6)	(6)	19
Net earnings (loss) attributable to Celanese Corporation	681	730	91
Consolidation Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	(1,113)	(1,095)	(1,221)
Cost of sales	1,108	1,101	1,270
Gross profit	(5)	6	49
Selling, general and administrative expenses	0	0	0
Amortization of intangible assets	0	0	0
Research and development expenses	0	0	0
Other (charges) gains, net	0	0	0
Foreign exchange gain (loss), net	0	0	0
Gain (loss) on disposition of businesses and assets, net	0	(6)	0
Operating profit (loss)	(5)	0	49
Equity in net earnings (loss) of affiliates	(2,284)	(2,481)	(681)
Interest expense	32	19	70
Refinancing expense	0	0	0
Interest income	(32)	(19)	(70)
Dividend income - cost investments	(3)	1	0
Other income (expense), net	0	0	0
Earnings (loss) from continuing operations before tax	(2,292)	(2,480)	(632)
Income tax (provision) benefit	0	(3)	(21)
Earnings (loss) from continuing operations	(2,292)	(2,483)	(653)
Earnings (loss) from operation of discontinued operations	0	0	0
Gain (loss) on disposition of discontinued operations	0	0	0
Income tax (provision) benefit from discontinued operations	0	0	0
Earnings (loss) from discontinued operations	0	0	0
Net earnings (loss)	(2,292)	(2,483)	(653)
Net (earnings) loss attributable to noncontrolling interests	0	0	0
Net earnings (loss) attributable to Celanese Corporation	$ (2,292)	$ (2,483)	$ (653)