Consolidating Guarantor Financial Information (Schedule of Consolidating Statement of Operations) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 1,566	$ 1,323	$ 4,547	$ 4,078
Cost of sales	(1,181)	(968)	(3,443)	(2,995)
Gross profit	385	355	1,104	1,083
Selling, general and administrative expenses	(112)	(81)	(291)	(232)
Amortization of intangible assets	(5)	(3)	(14)	(7)
Research and development expenses	(19)	(20)	(53)	(58)
Other (charges) gains, net	0	(3)	(58)	(12)
Foreign exchange gain (loss), net	4	(1)	0	1
Gain (loss) on disposition of businesses and assets, net	(1)	(1)	(4)	1
Operating profit (loss)	252	246	684	776
Equity in net earnings (loss) of affiliates	50	41	135	114
Interest expense	(32)	(28)	(91)	(91)
Refinancing expense	0	(4)	0	(6)
Interest income	1	0	2	1
Dividend income - cost investments	24	26	82	82
Other income (expense), net	(6)	0	(2)	(2)
Earnings (loss) from continuing operations before tax	289	281	810	874
Income tax (provision) benefit	(57)	(15)	(153)	(127)
Earnings (loss) from continuing operations	232	266	657	747
Earnings (loss) from operation of discontinued operations	(5)	(4)	(14)	(3)
Income tax (provision) benefit from discontinued operations	1	1	2	1
Earnings (loss) from discontinued operations	(4)	(3)	(12)	(2)
Net earnings (loss)	228	263	645	745
Net (earnings) loss attributable to noncontrolling interests	(2)	(1)	(5)	(5)
Net earnings (loss) attributable to Celanese Corporation	226	262	640	740
Parent Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	0	0	0	0
Cost of sales	0	0	0	0
Gross profit	0	0	0	0
Selling, general and administrative expenses	0	0	0	0
Amortization of intangible assets	0	0	0	0
Research and development expenses	0	0	0	0
Other (charges) gains, net	0	0	0	0
Foreign exchange gain (loss), net	0	0	0	0
Gain (loss) on disposition of businesses and assets, net	0	0	0	0
Operating profit (loss)	0	0	0	0
Equity in net earnings (loss) of affiliates	226	262	640	740
Interest expense	0	0	0	0
Refinancing expense	0	0	0	0
Interest income	0	0	0	0
Dividend income - cost investments	0	0	0	0
Other income (expense), net	0	0	0	0
Earnings (loss) from continuing operations before tax	226	262	640	740
Income tax (provision) benefit	0	0	0	0
Earnings (loss) from continuing operations	226	262	640	740
Earnings (loss) from operation of discontinued operations	0	0	0	0
Income tax (provision) benefit from discontinued operations	0	0	0	0
Earnings (loss) from discontinued operations	0	0	0	0
Net earnings (loss)	226	262	640	740
Net (earnings) loss attributable to noncontrolling interests	0	0	0	0
Net earnings (loss) attributable to Celanese Corporation	226	262	640	740
Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	0	0	0	0
Cost of sales	0	0	0	0
Gross profit	0	0	0	0
Selling, general and administrative expenses	0	0	0	0
Amortization of intangible assets	0	0	0	0
Research and development expenses	0	0	0	0
Other (charges) gains, net	0	0	0	0
Foreign exchange gain (loss), net	0	0	0	0
Gain (loss) on disposition of businesses and assets, net	0	0	0	0
Operating profit (loss)	0	0	0	0
Equity in net earnings (loss) of affiliates	233	250	640	742
Interest expense	(5)	(5)	(17)	(11)
Refinancing expense	0	(4)	0	(4)
Interest income	7	3	19	7
Dividend income - cost investments	0	0	0	0
Other income (expense), net	(2)	0	(3)	(1)
Earnings (loss) from continuing operations before tax	233	244	639	733
Income tax (provision) benefit	(7)	18	1	7
Earnings (loss) from continuing operations	226	262	640	740
Earnings (loss) from operation of discontinued operations	0	0	0	0
Income tax (provision) benefit from discontinued operations	0	0	0	0
Earnings (loss) from discontinued operations	0	0	0	0
Net earnings (loss)	226	262	640	740
Net (earnings) loss attributable to noncontrolling interests	0	0	0	0
Net earnings (loss) attributable to Celanese Corporation	226	262	640	740
Subsidiary Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	527	544	1,679	1,663
Cost of sales	(405)	(414)	(1,305)	(1,270)
Gross profit	122	130	374	393
Selling, general and administrative expenses	(36)	(19)	(78)	(41)
Amortization of intangible assets	(1)	(1)	(3)	(3)
Research and development expenses	(9)	(8)	(23)	(24)
Other (charges) gains, net	0	0	(7)	(1)
Foreign exchange gain (loss), net	0	0	0	0
Gain (loss) on disposition of businesses and assets, net	(2)	(3)	(6)	(6)
Operating profit (loss)	74	99	257	318
Equity in net earnings (loss) of affiliates	175	169	439	472
Interest expense	(28)	(20)	(75)	(71)
Refinancing expense	0	0	0	(2)
Interest income	1	0	3	2
Dividend income - cost investments	0	0	0	0
Other income (expense), net	0	1	1	1
Earnings (loss) from continuing operations before tax	222	249	625	720
Income tax (provision) benefit	(68)	(23)	(139)	(63)
Earnings (loss) from continuing operations	154	226	486	657
Earnings (loss) from operation of discontinued operations	0	(2)	0	(2)
Income tax (provision) benefit from discontinued operations	0	0	0	0
Earnings (loss) from discontinued operations	0	(2)	0	(2)
Net earnings (loss)	154	224	486	655
Net (earnings) loss attributable to noncontrolling interests	0	0	0	0
Net earnings (loss) attributable to Celanese Corporation	154	224	486	655
Non-Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	1,314	1,052	3,713	3,264
Cost of sales	(1,042)	(824)	(2,974)	(2,580)
Gross profit	272	228	739	684
Selling, general and administrative expenses	(76)	(62)	(213)	(191)
Amortization of intangible assets	(4)	(2)	(11)	(4)
Research and development expenses	(10)	(12)	(30)	(34)
Other (charges) gains, net	0	(3)	(51)	(11)
Foreign exchange gain (loss), net	4	(1)	0	1
Gain (loss) on disposition of businesses and assets, net	1	2	2	7
Operating profit (loss)	187	150	436	452
Equity in net earnings (loss) of affiliates	45	36	122	107
Interest expense	(8)	(7)	(23)	(21)
Refinancing expense	0	0	0	0
Interest income	2	1	4	4
Dividend income - cost investments	26	26	85	82
Other income (expense), net	(4)	(1)	0	(2)
Earnings (loss) from continuing operations before tax	248	205	624	622
Income tax (provision) benefit	17	(11)	(16)	(70)
Earnings (loss) from continuing operations	265	194	608	552
Earnings (loss) from operation of discontinued operations	(5)	(2)	(14)	(1)
Income tax (provision) benefit from discontinued operations	1	1	2	1
Earnings (loss) from discontinued operations	(4)	(1)	(12)	0
Net earnings (loss)	261	193	596	552
Net (earnings) loss attributable to noncontrolling interests	(2)	(1)	(5)	(5)
Net earnings (loss) attributable to Celanese Corporation	259	192	591	547
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	(275)	(273)	(845)	(849)
Cost of sales	266	270	836	855
Gross profit	(9)	(3)	(9)	6
Selling, general and administrative expenses	0	0	0	0
Amortization of intangible assets	0	0	0	0
Research and development expenses	0	0	0	0
Other (charges) gains, net	0	0	0	0
Foreign exchange gain (loss), net	0	0	0	0
Gain (loss) on disposition of businesses and assets, net	0	0	0	0
Operating profit (loss)	(9)	(3)	(9)	6
Equity in net earnings (loss) of affiliates	(629)	(676)	(1,706)	(1,947)
Interest expense	9	4	24	12
Refinancing expense	0	0	0	0
Interest income	(9)	(4)	(24)	(12)
Dividend income - cost investments	(2)	0	(3)	0
Other income (expense), net	0	0	0	0
Earnings (loss) from continuing operations before tax	(640)	(679)	(1,718)	(1,941)
Income tax (provision) benefit	1	1	1	(1)
Earnings (loss) from continuing operations	(639)	(678)	(1,717)	(1,942)
Earnings (loss) from operation of discontinued operations	0	0	0	0
Income tax (provision) benefit from discontinued operations	0	0	0	0
Earnings (loss) from discontinued operations	0	0	0	0
Net earnings (loss)	(639)	(678)	(1,717)	(1,942)
Net (earnings) loss attributable to noncontrolling interests	0	0	0	0
Net earnings (loss) attributable to Celanese Corporation	$ (639)	$ (678)	$ (1,717)	$ (1,942)