Consolidating Guarantor Financial Information (Schedule of Consolidating Statements of Operations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 6,297	$ 7,155	$ 6,140
Cost of sales	(4,691)	(5,183)	(4,629)
Gross profit	1,606	1,972	1,511
Selling, general and administrative expenses	(483)	(546)	(496)
Amortization of intangible assets	(24)	(24)	(20)
Research and development expenses	(67)	(72)	(73)
Other (charges) gains, net	(203)	9	(59)
Foreign exchange gain (loss), net	7	0	(1)
Gain (loss) on disposition of businesses and assets, net	(2)	(5)	(5)
Operating profit (loss)	834	1,334	857
Equity in net earnings (loss) of affiliates	182	233	183
Non-operating pension and other postretirement employee benefit (expense) income	(20)	(62)	44
Interest expense	(115)	(125)	(122)
Refinancing expense	(4)	(1)	0
Interest income	6	6	2
Dividend income - equity investments	113	117	108
Other income (expense), net	(8)	8	3
Earnings (loss) from continuing operations before tax	988	1,510	1,075
Income tax (provision) benefit	(124)	(292)	(213)
Earnings (loss) from continuing operations	864	1,218	862
Earnings (loss) from operation of discontinued operations	(8)	(5)	(16)
Gain (loss) on disposition of discontinued operations	0	0	0
Income tax (provision) benefit from discontinued operations	2	0	3
Earnings (loss) from discontinued operations	(6)	(5)	(13)
Net earnings (loss)	858	1,213	849
Net (earnings) loss attributable to noncontrolling interests	(6)	(6)	(6)
Net earnings (loss) attributable to Celanese Corporation	852	1,207	843
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	881	1,207	843
Non-operating pension and other postretirement employee benefit (expense) income	0	0	0
Interest expense	(29)	0	0
Refinancing expense	0	0
Interest income	0	0	0
Dividend income - equity investments	0	0	0
Other income (expense), net	0	0	0
Earnings (loss) from continuing operations before tax	852	1,207	843
Income tax (provision) benefit	0	0	0
Earnings (loss) from continuing operations	852	1,207	843
Earnings (loss) from operation 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)	852	1,207	843
Net (earnings) loss attributable to noncontrolling interests	0	0	0
Net earnings (loss) attributable to Celanese Corporation	852	1,207	843
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	(3)	0
Gain (loss) on disposition of businesses and assets, net	0	0	0
Operating profit (loss)	0	(3)	0
Equity in net earnings (loss) of affiliates	856	1,202	867
Non-operating pension and other postretirement employee benefit (expense) income	0	0	0
Interest expense	(39)	(30)	(20)
Refinancing expense	(4)	(1)
Interest income	63	45	25
Dividend income - equity investments	0	0	0
Other income (expense), net	(7)	5	(3)
Earnings (loss) from continuing operations before tax	869	1,218	869
Income tax (provision) benefit	12	(11)	(26)
Earnings (loss) from continuing operations	881	1,207	843
Earnings (loss) from operation 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)	881	1,207	843
Net (earnings) loss attributable to noncontrolling interests	0	0	0
Net earnings (loss) attributable to Celanese Corporation	881	1,207	843
Subsidiary Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	2,298	2,387	2,240
Cost of sales	(1,795)	(1,898)	(1,723)
Gross profit	503	489	517
Selling, general and administrative expenses	(179)	(213)	(189)
Amortization of intangible assets	(8)	(8)	(4)
Research and development expenses	(27)	(30)	(32)
Other (charges) gains, net	(8)	0	(6)
Foreign exchange gain (loss), net	0	0	0
Gain (loss) on disposition of businesses and assets, net	(9)	(10)	(8)
Operating profit (loss)	272	228	278
Equity in net earnings (loss) of affiliates	551	1,033	591
Non-operating pension and other postretirement employee benefit (expense) income	13	(28)	60
Interest expense	(127)	(118)	(104)
Refinancing expense	0	0
Interest income	49	7	4
Dividend income - equity investments	0	0	0
Other income (expense), net	1	1	2
Earnings (loss) from continuing operations before tax	759	1,123	831
Income tax (provision) benefit	23	(106)	(62)
Earnings (loss) from continuing operations	782	1,017	769
Earnings (loss) from operation of discontinued operations	(8)	3	(2)
Income tax (provision) benefit from discontinued operations	2	(1)	1
Earnings (loss) from discontinued operations	(6)	2	(1)
Net earnings (loss)	776	1,019	768
Net (earnings) loss attributable to noncontrolling interests	0	0	0
Net earnings (loss) attributable to Celanese Corporation	776	1,019	768
Non-Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	5,137	5,954	5,013
Cost of sales	(4,036)	(4,471)	(4,014)
Gross profit	1,101	1,483	999
Selling, general and administrative expenses	(304)	(333)	(307)
Amortization of intangible assets	(16)	(16)	(16)
Research and development expenses	(40)	(42)	(41)
Other (charges) gains, net	(195)	9	(53)
Foreign exchange gain (loss), net	7	3	(1)
Gain (loss) on disposition of businesses and assets, net	7	5	3
Operating profit (loss)	560	1,109	584
Equity in net earnings (loss) of affiliates	165	220	166
Non-operating pension and other postretirement employee benefit (expense) income	(33)	(34)	(16)
Interest expense	(37)	(33)	(30)
Refinancing expense	0	0
Interest income	11	10	5
Dividend income - equity investments	113	113	111
Other income (expense), net	(2)	3	4
Earnings (loss) from continuing operations before tax	777	1,388	824
Income tax (provision) benefit	(158)	(176)	(125)
Earnings (loss) from continuing operations	619	1,212	699
Earnings (loss) from operation of discontinued operations	0	(8)	(14)
Income tax (provision) benefit from discontinued operations	0	1	2
Earnings (loss) from discontinued operations	0	(7)	(12)
Net earnings (loss)	619	1,205	687
Net (earnings) loss attributable to noncontrolling interests	(6)	(6)	(6)
Net earnings (loss) attributable to Celanese Corporation	613	1,199	681
Consolidation Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	(1,138)	(1,186)	(1,113)
Cost of sales	1,140	1,186	1,108
Gross profit	2	0	(5)
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)	2	0	(5)
Equity in net earnings (loss) of affiliates	(2,271)	(3,429)	(2,284)
Non-operating pension and other postretirement employee benefit (expense) income	0	0	0
Interest expense	117	56	32
Refinancing expense	0	0
Interest income	(117)	(56)	(32)
Dividend income - equity investments	0	4	(3)
Other income (expense), net	0	(1)	0
Earnings (loss) from continuing operations before tax	(2,269)	(3,426)	(2,292)
Income tax (provision) benefit	(1)	1	0
Earnings (loss) from continuing operations	(2,270)	(3,425)	(2,292)
Earnings (loss) from operation 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)	(2,270)	(3,425)	(2,292)
Net (earnings) loss attributable to noncontrolling interests	0	0	0
Net earnings (loss) attributable to Celanese Corporation	$ (2,270)	$ (3,425)	$ (2,292)