Consolidating Guarantor Financial Information (Schedule of Consolidating Statement of Operations) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 1,592	$ 1,844	$ 3,279	$ 3,695
Cost of sales	(1,169)	(1,323)	(2,403)	(2,659)
Gross profit	423	521	876	1,036
Selling, general and administrative expenses	(118)	(136)	(238)	(283)
Amortization of intangible assets	(6)	(7)	(12)	(13)
Research and development expenses	(17)	(18)	(33)	(36)
Other (charges) gains, net	(98)	(3)	(94)	(3)
Foreign exchange gain (loss), net	1	3	6	2
Gain (loss) on disposition of businesses and assets, net	1	(2)	1	(2)
Operating profit (loss)	186	358	506	701
Equity in net earnings (loss) of affiliates	39	56	89	114
Non-operating pension and other postretirement employee benefit (expense) income	17	26	34	52
Interest expense	(29)	(32)	(60)	(65)
Refinancing expense	4	0	4	0
Interest income	2	0	3	2
Dividend income - equity investments	30	34	62	66
Other income (expense), net	(2)	0	(6)	4
Earnings (loss) from continuing operations before tax	239	442	624	874
Income tax (provision) benefit	(28)	(97)	(74)	(162)
Earnings (loss) from continuing operations	211	345	550	712
Earnings (loss) from operation of discontinued operations	(2)	0	(3)	(2)
Income tax (provision) benefit from discontinued operations	1	0	1	0
Earnings (loss) from discontinued operations	(1)	0	(2)	(2)
Net earnings (loss)	210	345	548	710
Net (earnings) loss attributable to noncontrolling interests	(1)	(1)	(2)	(3)
Net earnings (loss) attributable to Celanese Corporation	209	344	546	707
Write off of Deferred Debt Issuance Cost	(4)	0	(4)	0
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	209	344	546	707
Non-operating pension and other postretirement employee benefit (expense) income	0	0	0	0
Interest expense	0	0	0	0
Refinancing expense	0		0
Interest income	0	0	0	0
Dividend income - equity investments	0	0	0	0
Other income (expense), net	0	0	0	0
Earnings (loss) from continuing operations before tax	209	344	546	707
Income tax (provision) benefit	0	0	0	0
Earnings (loss) from continuing operations	209	344	546	707
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)	209	344	546	707
Net (earnings) loss attributable to noncontrolling interests	0	0	0	0
Net earnings (loss) attributable to Celanese Corporation	209	344	546	707
Write off of Deferred Debt Issuance Cost	0		0
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	210	341	547	701
Non-operating pension and other postretirement employee benefit (expense) income	0	0	0	0
Interest expense	(9)	(5)	(19)	(10)
Refinancing expense	4		4
Interest income	18	10	31	18
Dividend income - equity investments	0	0	0	0
Other income (expense), net	(4)	(1)	(3)	0
Earnings (loss) from continuing operations before tax	211	345	552	709
Income tax (provision) benefit	(2)	(1)	(6)	(2)
Earnings (loss) from continuing operations	209	344	546	707
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)	209	344	546	707
Net (earnings) loss attributable to noncontrolling interests	0	0	0	0
Net earnings (loss) attributable to Celanese Corporation	209	344	546	707
Write off of Deferred Debt Issuance Cost	(4)		(4)
Subsidiary Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	586	586	1,210	1,168
Cost of sales	(443)	(457)	(901)	(905)
Gross profit	143	129	309	263
Selling, general and administrative expenses	(39)	(51)	(79)	(110)
Amortization of intangible assets	(2)	(1)	(4)	(2)
Research and development expenses	(7)	(7)	(13)	(15)
Other (charges) gains, net	(5)	0	(5)	0
Foreign exchange gain (loss), net	0	0	0	0
Gain (loss) on disposition of businesses and assets, net	(2)	(3)	(4)	(5)
Operating profit (loss)	88	67	204	131
Equity in net earnings (loss) of affiliates	122	312	339	586
Non-operating pension and other postretirement employee benefit (expense) income	16	24	31	47
Interest expense	(35)	(31)	(66)	(60)
Refinancing expense	0		0
Interest income	11	2	13	4
Dividend income - equity investments	0	0	0	0
Other income (expense), net	0	0	0	0
Earnings (loss) from continuing operations before tax	202	374	521	708
Income tax (provision) benefit	(23)	(69)	(30)	(105)
Earnings (loss) from continuing operations	179	305	491	603
Earnings (loss) from operation of discontinued operations	(2)	(1)	(3)	(1)
Income tax (provision) benefit from discontinued operations	1	0	1	0
Earnings (loss) from discontinued operations	(1)	(1)	(2)	(1)
Net earnings (loss)	178	304	489	602
Net (earnings) loss attributable to noncontrolling interests	0	0	0	0
Net earnings (loss) attributable to Celanese Corporation	178	304	489	602
Write off of Deferred Debt Issuance Cost	0		0
Non-Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	1,298	1,566	2,671	3,138
Cost of sales	(1,020)	(1,171)	(2,097)	(2,365)
Gross profit	278	395	574	773
Selling, general and administrative expenses	(79)	(85)	(159)	(173)
Amortization of intangible assets	(4)	(6)	(8)	(11)
Research and development expenses	(10)	(11)	(20)	(21)
Other (charges) gains, net	(93)	(3)	(89)	(3)
Foreign exchange gain (loss), net	1	3	6	2
Gain (loss) on disposition of businesses and assets, net	3	1	5	3
Operating profit (loss)	96	294	309	570
Equity in net earnings (loss) of affiliates	34	53	77	106
Non-operating pension and other postretirement employee benefit (expense) income	1	2	3	5
Interest expense	(13)	(8)	(20)	(17)
Refinancing expense	0		0
Interest income	1	2	4	4
Dividend income - equity investments	30	32	62	64
Other income (expense), net	2	1	(3)	4
Earnings (loss) from continuing operations before tax	151	376	432	736
Income tax (provision) benefit	(3)	(28)	(39)	(55)
Earnings (loss) from continuing operations	148	348	393	681
Earnings (loss) from operation of discontinued operations	0	1	0	(1)
Income tax (provision) benefit from discontinued operations	0	0	0	0
Earnings (loss) from discontinued operations	0	1	0	(1)
Net earnings (loss)	148	349	393	680
Net (earnings) loss attributable to noncontrolling interests	(1)	(1)	(2)	(3)
Net earnings (loss) attributable to Celanese Corporation	147	348	391	677
Write off of Deferred Debt Issuance Cost	0		0
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	(292)	(308)	(602)	(611)
Cost of sales	294	305	595	611
Gross profit	2	(3)	(7)	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)	2	(3)	(7)	0
Equity in net earnings (loss) of affiliates	(536)	(994)	(1,420)	(1,986)
Non-operating pension and other postretirement employee benefit (expense) income	0	0	0	0
Interest expense	28	12	45	22
Refinancing expense	0		0
Interest income	(28)	(14)	(45)	(24)
Dividend income - equity investments	0	2	0	2
Other income (expense), net	0	0	0	0
Earnings (loss) from continuing operations before tax	(534)	(997)	(1,427)	(1,986)
Income tax (provision) benefit	0	1	1	0
Earnings (loss) from continuing operations	(534)	(996)	(1,426)	(1,986)
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)	(534)	(996)	(1,426)	(1,986)
Net (earnings) loss attributable to noncontrolling interests	0	0	0	0
Net earnings (loss) attributable to Celanese Corporation	(534)	$ (996)	(1,426)	$ (1,986)
Write off of Deferred Debt Issuance Cost	$ 0		$ 0