Consolidating Guarantor Financial Information (Schedule of Consolidating Balance Sheet) (Details) - USD ($) $ in Millions	Mar. 31, 2018		Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Current Assets
Cash and cash equivalents	$ 490		$ 576	$ 501	$ 638
Trade receivables - third party and affiliates	1,205		986
Non-trade receivables, net (variable interest entity restricted - 2018: $1; 2017: $0)	271		244
Inventories, net	955		900
Marketable securities, at fair value	32		32
Other assets	53		54
Total current assets	3,006		2,792
Investments in affiliates	979		976
Property, Plant and Equipment, Net	3,801		3,762
Deferred income taxes	182		366
Other assets	369		338
Goodwill	1,107	[1]	1,003
Intangible Assets, Net (Excluding Goodwill)	336		301
Total assets	9,780		9,538
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	425		326
Trade payables - third party and affiliates	797		807
Other liabilities	266		354
Income taxes payable	114		72
Total current liabilities	1,602		1,559
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	3,343		3,315
Deferred income taxes	219		211
Uncertain tax positions	152		156
Benefit obligations	582		585
Other liabilities	217		413
Total noncurrent liabilities	4,513		4,680
Total Celanese Corporation stockholders' equity	3,253		2,887
Noncontrolling interests	412		412
Total equity	3,665		3,299
Total liabilities and equity	9,780		9,538
Parent Guarantor [Member]
Current Assets
Cash and cash equivalents	0		0	0	0
Trade receivables - third party and affiliates	0		0
Non-trade receivables, net (variable interest entity restricted - 2018: $1; 2017: $0)	38		38
Inventories, net	0		0
Marketable securities, at fair value	0		0
Other assets	0		0
Total current assets	38		38
Investments in affiliates	3,215		2,850
Property, Plant and Equipment, Net	0		0
Deferred income taxes	0		0
Other assets	0		0
Goodwill	0		0
Intangible Assets, Net (Excluding Goodwill)	0		0
Total assets	3,253		2,888
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	0		0
Trade payables - third party and affiliates	0		0
Other liabilities	0		0
Income taxes payable	0		0
Total current liabilities	0		0
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	0		0
Deferred income taxes	0		0
Uncertain tax positions	0		0
Benefit obligations	0		0
Other liabilities	0		0
Total noncurrent liabilities	0		0
Total Celanese Corporation stockholders' equity	3,253		2,888
Noncontrolling interests	0		0
Total equity	3,253		2,888
Total liabilities and equity	3,253		2,888
Issuer [Member]
Current Assets
Cash and cash equivalents	2		0	0	0
Trade receivables - third party and affiliates	0		0
Non-trade receivables, net (variable interest entity restricted - 2018: $1; 2017: $0)	486		482
Inventories, net	0		0
Marketable securities, at fair value	0		0
Other assets	14		60
Total current assets	502		542
Investments in affiliates	4,461		4,283
Property, Plant and Equipment, Net	0		0
Deferred income taxes	14		6
Other assets	1,519		1,295
Goodwill	0		0
Intangible Assets, Net (Excluding Goodwill)	0		0
Total assets	6,496		6,126
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	83		76
Trade payables - third party and affiliates	0		1
Other liabilities	38		71
Income taxes payable	0		0
Total current liabilities	121		148
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	3,160		3,128
Deferred income taxes	0		0
Uncertain tax positions	0		0
Benefit obligations	0		0
Other liabilities	0		0
Total noncurrent liabilities	3,160		3,128
Total Celanese Corporation stockholders' equity	3,215		2,850
Noncontrolling interests	0		0
Total equity	3,215		2,850
Total liabilities and equity	6,496		6,126
Subsidiary Guarantors [Member]
Current Assets
Cash and cash equivalents	111		230	56	51
Trade receivables - third party and affiliates	160		89
Non-trade receivables, net (variable interest entity restricted - 2018: $1; 2017: $0)	301		279
Inventories, net	281		277
Marketable securities, at fair value	32		32
Other assets	8		12
Total current assets	893		919
Investments in affiliates	4,140		3,916
Property, Plant and Equipment, Net	1,181		1,145
Deferred income taxes	12		206
Other assets	214		171
Goodwill	399		314
Intangible Assets, Net (Excluding Goodwill)	82		48
Total assets	6,921		6,719
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	151		148
Trade payables - third party and affiliates	288		300
Other liabilities	264		302
Income taxes payable	501		471
Total current liabilities	1,204		1,221
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	1,476		1,254
Deferred income taxes	0		0
Uncertain tax positions	9		1
Benefit obligations	273		277
Other liabilities	55		255
Total noncurrent liabilities	1,813		1,787
Total Celanese Corporation stockholders' equity	3,904		3,711
Noncontrolling interests	0		0
Total equity	3,904		3,711
Total liabilities and equity	6,921		6,719
Non-Guarantors [Member]
Current Assets
Cash and cash equivalents	377		346	445	587
Trade receivables - third party and affiliates	1,209		988
Non-trade receivables, net (variable interest entity restricted - 2018: $1; 2017: $0)	441		385
Inventories, net	719		672
Marketable securities, at fair value	0		0
Other assets	55		93
Total current assets	2,801		2,484
Investments in affiliates	861		861
Property, Plant and Equipment, Net	2,620		2,617
Deferred income taxes	159		158
Other assets	153		165
Goodwill	708		689
Intangible Assets, Net (Excluding Goodwill)	254		253
Total assets	7,556		7,227
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	466		369
Trade payables - third party and affiliates	673		598
Other liabilities	217		273
Income taxes payable	103		92
Total current liabilities	1,459		1,332
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	231		233
Deferred income taxes	223		215
Uncertain tax positions	145		157
Benefit obligations	309		308
Other liabilities	162		158
Total noncurrent liabilities	1,070		1,071
Total Celanese Corporation stockholders' equity	4,615		4,412
Noncontrolling interests	412		412
Total equity	5,027		4,824
Total liabilities and equity	7,556		7,227
Eliminations [Member]
Current Assets
Cash and cash equivalents	0		0	$ 0	$ 0
Trade receivables - third party and affiliates	(164)		(91)
Non-trade receivables, net (variable interest entity restricted - 2018: $1; 2017: $0)	(995)		(940)
Inventories, net	(45)		(49)
Marketable securities, at fair value	0		0
Other assets	(24)		(111)
Total current assets	(1,228)		(1,191)
Investments in affiliates	(11,698)		(10,934)
Property, Plant and Equipment, Net	0		0
Deferred income taxes	(3)		(4)
Other assets	(1,517)		(1,293)
Goodwill	0		0
Intangible Assets, Net (Excluding Goodwill)	0		0
Total assets	(14,446)		(13,422)
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	(275)		(267)
Trade payables - third party and affiliates	(164)		(92)
Other liabilities	(253)		(292)
Income taxes payable	(490)		(491)
Total current liabilities	(1,182)		(1,142)
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	(1,524)		(1,300)
Deferred income taxes	(4)		(4)
Uncertain tax positions	(2)		(2)
Benefit obligations	0		0
Other liabilities	0		0
Total noncurrent liabilities	(1,530)		(1,306)
Total Celanese Corporation stockholders' equity	(11,734)		(10,974)
Noncontrolling interests	0		0
Total equity	(11,734)		(10,974)
Total liabilities and equity	$ (14,446)		$ (13,422)

[1] There were $0 million of accumulated impairment losses as of March 31, 2018.