Consolidating Guarantor Financial Information (Schedule of Consolidating Balance Sheet) (Details) - USD ($) $ in Millions	Jun. 30, 2018		Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Current Assets
Cash and cash equivalents	$ 708		$ 576	$ 511	$ 638
Trade receivables - third party and affiliates	1,156		986
Non-trade receivables, net	289		244
Inventories, net	917		900
Marketable securities, at fair value	32		32
Other assets	51		54
Total current assets	3,153		2,792
Investments in affiliates	963		976
Property, Plant and Equipment, Net	3,724		3,762
Deferred income taxes	163		366
Other assets	392		338
Goodwill	1,069	[1]	1,003
Intangible Assets, Net (Excluding Goodwill)	325		301
Total assets	9,789		9,538
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	366		326
Trade payables - third party and affiliates	819		807
Other liabilities	314		354
Income taxes payable	111		72
Total current liabilities	1,610		1,559
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	3,228		3,315
Deferred income taxes	248		211
Uncertain tax positions	149		156
Benefit obligations	557		585
Other liabilities	210		413
Total noncurrent liabilities	4,392		4,680
Total Celanese Corporation stockholders' equity	3,380		2,887
Noncontrolling interests	407		412
Total equity	3,787		3,299
Total liabilities and equity	9,789		9,538
Parent Guarantor [Member]
Current Assets
Cash and cash equivalents	2		0	0	0
Trade receivables - third party and affiliates	0		0
Non-trade receivables, net	37		38
Inventories, net	0		0
Marketable securities, at fair value	0		0
Other assets	0		0
Total current assets	39		38
Investments in affiliates	3,341		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	3,380		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	3,380		2,888
Noncontrolling interests	0		0
Total equity	3,380		2,888
Total liabilities and equity	3,380		2,888
Issuer [Member]
Current Assets
Cash and cash equivalents	0		0	3	0
Trade receivables - third party and affiliates	0		0
Non-trade receivables, net	506		482
Inventories, net	0		0
Marketable securities, at fair value	0		0
Other assets	50		60
Total current assets	556		542
Investments in affiliates	4,510		4,283
Property, Plant and Equipment, Net	0		0
Deferred income taxes	13		6
Other assets	1,565		1,295
Goodwill	0		0
Intangible Assets, Net (Excluding Goodwill)	0		0
Total assets	6,644		6,126
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	169		76
Trade payables - third party and affiliates	0		1
Other liabilities	74		71
Income taxes payable	0		0
Total current liabilities	243		148
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	3,060		3,128
Deferred income taxes	0		0
Uncertain tax positions	0		0
Benefit obligations	0		0
Other liabilities	0		0
Total noncurrent liabilities	3,060		3,128
Total Celanese Corporation stockholders' equity	3,341		2,850
Noncontrolling interests	0		0
Total equity	3,341		2,850
Total liabilities and equity	6,644		6,126
Subsidiary Guarantors [Member]
Current Assets
Cash and cash equivalents	93		230	57	51
Trade receivables - third party and affiliates	125		89
Non-trade receivables, net	452		279
Inventories, net	259		277
Marketable securities, at fair value	32		32
Other assets	16		12
Total current assets	977		919
Investments in affiliates	4,329		3,916
Property, Plant and Equipment, Net	1,200		1,145
Deferred income taxes	0		206
Other assets	240		171
Goodwill	314		314
Intangible Assets, Net (Excluding Goodwill)	103		48
Total assets	7,163		6,719
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	163		148
Trade payables - third party and affiliates	327		300
Other liabilities	267		302
Income taxes payable	488		471
Total current liabilities	1,245		1,221
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	1,525		1,254
Deferred income taxes	67		0
Uncertain tax positions	9		1
Benefit obligations	269		277
Other liabilities	105		255
Total noncurrent liabilities	1,975		1,787
Total Celanese Corporation stockholders' equity	3,943		3,711
Noncontrolling interests	0		0
Total equity	3,943		3,711
Total liabilities and equity	7,163		6,719
Non-Guarantors [Member]
Current Assets
Cash and cash equivalents	613		346	451	587
Trade receivables - third party and affiliates	1,180		988
Non-trade receivables, net	416		385
Inventories, net	710		672
Marketable securities, at fair value	0		0
Other assets	75		93
Total current assets	2,994		2,484
Investments in affiliates	844		861
Property, Plant and Equipment, Net	2,524		2,617
Deferred income taxes	172		158
Other assets	192		165
Goodwill	755		689
Intangible Assets, Net (Excluding Goodwill)	222		253
Total assets	7,703		7,227
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	286		369
Trade payables - third party and affiliates	641		598
Other liabilities	445		273
Income taxes payable	113		92
Total current liabilities	1,485		1,332
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	213		233
Deferred income taxes	203		215
Uncertain tax positions	142		157
Benefit obligations	288		308
Other liabilities	147		158
Total noncurrent liabilities	993		1,071
Total Celanese Corporation stockholders' equity	4,818		4,412
Noncontrolling interests	407		412
Total equity	5,225		4,824
Total liabilities and equity	7,703		7,227
Eliminations [Member]
Current Assets
Cash and cash equivalents	0		0	$ 0	$ 0
Trade receivables - third party and affiliates	(149)		(91)
Non-trade receivables, net	(1,122)		(940)
Inventories, net	(52)		(49)
Marketable securities, at fair value	0		0
Other assets	(90)		(111)
Total current assets	(1,413)		(1,191)
Investments in affiliates	(12,061)		(10,934)
Property, Plant and Equipment, Net	0		0
Deferred income taxes	(22)		(4)
Other assets	(1,605)		(1,293)
Goodwill	0		0
Intangible Assets, Net (Excluding Goodwill)	0		0
Total assets	(15,101)		(13,422)
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	(252)		(267)
Trade payables - third party and affiliates	(149)		(92)
Other liabilities	(472)		(292)
Income taxes payable	(490)		(491)
Total current liabilities	(1,363)		(1,142)
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	(1,570)		(1,300)
Deferred income taxes	(22)		(4)
Uncertain tax positions	(2)		(2)
Benefit obligations	0		0
Other liabilities	(42)		0
Total noncurrent liabilities	(1,636)		(1,306)
Total Celanese Corporation stockholders' equity	(12,102)		(10,974)
Noncontrolling interests	0		0
Total equity	(12,102)		(10,974)
Total liabilities and equity	$ (15,101)		$ (13,422)

[1] There were $0 million of accumulated impairment losses as of June 30, 2018.