Consolidating Guarantor Financial Information (Schedule of Consolidating Statement of Operations) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 1,851	$ 1,471
Cost of sales	(1,336)	(1,121)
Gross profit	515	350
Selling, general and administrative expenses	(147)	(103)
Amortization of intangible assets	(6)	(4)
Research and development expenses	(18)	(17)
Other (charges) gains, net	0	(55)
Foreign exchange gain (loss), net	(1)	0
Gain (loss) on disposition of businesses and assets, net	0	(1)
Operating profit (loss)	343	170
Equity in net earnings (loss) of affiliates	58	47
Non-operating pension and other postretirement employee benefit (expense) income	26	22
Interest expense	(33)	(29)
Interest income	2	0
Dividend income - cost investments	32	29
Other income (expense), net	4	1
Earnings (loss) from continuing operations before tax	432	240
Income tax (provision) benefit	(65)	(56)
Earnings (loss) from continuing operations	367	184
Earnings (loss) from operation of discontinued operations	(2)	0
Income tax (provision) benefit from discontinued operations	0	0
Earnings (loss) from discontinued operations	(2)	0
Net earnings (loss)	365	184
Net (earnings) loss attributable to noncontrolling interests	(2)	(1)
Net earnings (loss) attributable to Celanese Corporation	363	183
Parent Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	0	0
Cost of sales	0	0
Gross profit	0	0
Selling, general and administrative expenses	0	0
Amortization of intangible assets	0	0
Research and development expenses	0	0
Other (charges) gains, net	0	0
Foreign exchange gain (loss), net	0	0
Gain (loss) on disposition of businesses and assets, net	0	0
Operating profit (loss)	0	0
Equity in net earnings (loss) of affiliates	363	183
Non-operating pension and other postretirement employee benefit (expense) income	0	0
Interest expense	0	0
Interest income	0	0
Dividend income - cost investments	0	0
Other income (expense), net	0	0
Earnings (loss) from continuing operations before tax	363	183
Income tax (provision) benefit	0	0
Earnings (loss) from continuing operations	363	183
Earnings (loss) from operation of discontinued operations	0	0
Income tax (provision) benefit from discontinued operations	0	0
Earnings (loss) from discontinued operations	0	0
Net earnings (loss)	363	183
Net (earnings) loss attributable to noncontrolling interests	0	0
Net earnings (loss) attributable to Celanese Corporation	363	183
Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	0	0
Cost of sales	0	0
Gross profit	0	0
Selling, general and administrative expenses	0	0
Amortization of intangible assets	0	0
Research and development expenses	0	0
Other (charges) gains, net	0	0
Foreign exchange gain (loss), net	0	0
Gain (loss) on disposition of businesses and assets, net	0	0
Operating profit (loss)	0	0
Equity in net earnings (loss) of affiliates	360	174
Non-operating pension and other postretirement employee benefit (expense) income	0	0
Interest expense	(5)	(6)
Interest income	8	6
Dividend income - cost investments	0	0
Other income (expense), net	1	0
Earnings (loss) from continuing operations before tax	364	174
Income tax (provision) benefit	(1)	9
Earnings (loss) from continuing operations	363	183
Earnings (loss) from operation of discontinued operations	0	0
Income tax (provision) benefit from discontinued operations	0	0
Earnings (loss) from discontinued operations	0	0
Net earnings (loss)	363	183
Net (earnings) loss attributable to noncontrolling interests	0	0
Net earnings (loss) attributable to Celanese Corporation	363	183
Subsidiary Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	600	589
Cost of sales	(464)	(445)
Gross profit	136	144
Selling, general and administrative expenses	(60)	(34)
Amortization of intangible assets	(2)	(1)
Research and development expenses	(8)	(7)
Other (charges) gains, net	0	(6)
Foreign exchange gain (loss), net	0	0
Gain (loss) on disposition of businesses and assets, net	(2)	(2)
Operating profit (loss)	64	94
Equity in net earnings (loss) of affiliates	267	101
Non-operating pension and other postretirement employee benefit (expense) income	23	20
Interest expense	(29)	(23)
Interest income	2	1
Dividend income - cost investments	0	0
Other income (expense), net	1	0
Earnings (loss) from continuing operations before tax	328	193
Income tax (provision) benefit	(37)	(63)
Earnings (loss) from continuing operations	291	130
Earnings (loss) from operation of discontinued operations	0	0
Income tax (provision) benefit from discontinued operations	0	0
Earnings (loss) from discontinued operations	0	0
Net earnings (loss)	291	130
Net (earnings) loss attributable to noncontrolling interests	0	0
Net earnings (loss) attributable to Celanese Corporation	291	130
Non-Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	1,554	1,177
Cost of sales	(1,178)	(966)
Gross profit	376	211
Selling, general and administrative expenses	(87)	(69)
Amortization of intangible assets	(4)	(3)
Research and development expenses	(10)	(10)
Other (charges) gains, net	0	(49)
Foreign exchange gain (loss), net	(1)	0
Gain (loss) on disposition of businesses and assets, net	2	1
Operating profit (loss)	276	81
Equity in net earnings (loss) of affiliates	53	43
Non-operating pension and other postretirement employee benefit (expense) income	3	2
Interest expense	(9)	(7)
Interest income	2	0
Dividend income - cost investments	32	29
Other income (expense), net	2	1
Earnings (loss) from continuing operations before tax	359	149
Income tax (provision) benefit	(27)	1
Earnings (loss) from continuing operations	332	150
Earnings (loss) from operation of discontinued operations	(2)	0
Income tax (provision) benefit from discontinued operations	0	0
Earnings (loss) from discontinued operations	(2)	0
Net earnings (loss)	330	150
Net (earnings) loss attributable to noncontrolling interests	(2)	(1)
Net earnings (loss) attributable to Celanese Corporation	328	149
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	(303)	(295)
Cost of sales	306	290
Gross profit	3	(5)
Selling, general and administrative expenses	0	0
Amortization of intangible assets	0	0
Research and development expenses	0	0
Other (charges) gains, net	0	0
Foreign exchange gain (loss), net	0	0
Gain (loss) on disposition of businesses and assets, net	0	0
Operating profit (loss)	3	(5)
Equity in net earnings (loss) of affiliates	(985)	(454)
Non-operating pension and other postretirement employee benefit (expense) income	0	0
Interest expense	10	7
Interest income	(10)	(7)
Dividend income - cost investments	0	0
Other income (expense), net	0	0
Earnings (loss) from continuing operations before tax	(982)	(459)
Income tax (provision) benefit	0	(3)
Earnings (loss) from continuing operations	(982)	(462)
Earnings (loss) from operation of discontinued operations	0	0
Income tax (provision) benefit from discontinued operations	0	0
Earnings (loss) from discontinued operations	0	0
Net earnings (loss)	(982)	(462)
Net (earnings) loss attributable to noncontrolling interests	0	0
Net earnings (loss) attributable to Celanese Corporation	$ (982)	$ (462)