Consolidating Guarantor Financial Information (Schedule of Consolidating Balance Sheet) (Details) - USD ($) $ in Millions	Mar. 31, 2019		Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Current Assets
Cash and cash equivalents	$ 441		$ 439	$ 490	$ 576
Trade receivables - third party and affiliates	1,015		1,017
Non-trade receivables, net	343		301
Inventories, net	1,009		1,046
Marketable securities, at fair value	29		31
Other assets	47		40
Total current assets	2,884		2,874
Investments in affiliates	950		979
Property, Plant and Equipment, Net	3,721		3,719
Operating Lease, Right-of-Use Asset	210		0
Deferred income taxes	93		84
Other assets	309		290
Goodwill	1,075	[1]	1,057
Intangible Assets, Net (Excluding Goodwill)	332		310
Total assets	9,574		9,313
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	743		561
Trade payables - third party and affiliates	699		819
Other liabilities	311		343
Income taxes payable	69		56
Total current liabilities	1,822		1,779
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	2,933		2,970
Deferred income taxes	273		255
Uncertain tax positions	162		158
Benefit obligations	550		564
Operating Lease, Liability, Noncurrent	193		0
Other liabilities	202		208
Total noncurrent liabilities	4,313		4,155
Total Celanese Corporation stockholders' equity	3,047		2,984	3,253
Noncontrolling interests	392		395
Total equity	3,439		3,379	3,665
Total liabilities and equity	9,574		9,313
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	311		40
Inventories, net	0		0
Marketable securities, at fair value	0		0
Other assets	1		0
Total current assets	312		40
Investments in affiliates	3,563		3,503
Property, Plant and Equipment, Net	0		0
Operating Lease, Right-of-Use Asset	0
Deferred income taxes	0		0
Other assets	0		0
Goodwill	0		0
Intangible Assets, Net (Excluding Goodwill)	0		0
Total assets	3,875		3,543
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	826		544
Trade payables - third party and affiliates	0		13
Other liabilities	1		1
Income taxes payable	0		0
Total current liabilities	827		558
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
Operating Lease, Liability, Noncurrent	0
Other liabilities	1		1
Total noncurrent liabilities	1		1
Total Celanese Corporation stockholders' equity	3,047		2,984
Noncontrolling interests	0		0
Total equity	3,047		2,984
Total liabilities and equity	3,875		3,543
Issuer [Member]
Current Assets
Cash and cash equivalents	0		0	2	0
Trade receivables - third party and affiliates	0		0
Non-trade receivables, net	958		551
Inventories, net	0		0
Marketable securities, at fair value	0		0
Other assets	14		24
Total current assets	972		575
Investments in affiliates	4,718		4,820
Property, Plant and Equipment, Net	0		0
Operating Lease, Right-of-Use Asset	0
Deferred income taxes	0		0
Other assets	1,659		1,658
Goodwill	0		0
Intangible Assets, Net (Excluding Goodwill)	0		0
Total assets	7,349		7,053
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	635		333
Trade payables - third party and affiliates	1		1
Other liabilities	36		87
Income taxes payable	0		0
Total current liabilities	672		421
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	3,067		3,104
Deferred income taxes	24		15
Uncertain tax positions	2		0
Benefit obligations	0		0
Operating Lease, Liability, Noncurrent	0
Other liabilities	21		10
Total noncurrent liabilities	3,114		3,129
Total Celanese Corporation stockholders' equity	3,563		3,503
Noncontrolling interests	0		0
Total equity	3,563		3,503
Total liabilities and equity	7,349		7,053
Subsidiary Guarantors [Member]
Current Assets
Cash and cash equivalents	69		30	111	230
Trade receivables - third party and affiliates	119		96
Non-trade receivables, net	1,713		797
Inventories, net	316		329
Marketable securities, at fair value	29		31
Other assets	10		10
Total current assets	2,256		1,293
Investments in affiliates	4,022		4,678
Property, Plant and Equipment, Net	1,328		1,289
Operating Lease, Right-of-Use Asset	59
Deferred income taxes	0		0
Other assets	158		142
Goodwill	399		399
Intangible Assets, Net (Excluding Goodwill)	131		132
Total assets	8,353		7,933
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	994		465
Trade payables - third party and affiliates	254		342
Other liabilities	139		267
Income taxes payable	461		475
Total current liabilities	1,848		1,549
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	1,679		1,679
Deferred income taxes	104		85
Uncertain tax positions	6		6
Benefit obligations	246		250
Operating Lease, Liability, Noncurrent	48
Other liabilities	93		99
Total noncurrent liabilities	2,176		2,119
Total Celanese Corporation stockholders' equity	4,329		4,265
Noncontrolling interests	0		0
Total equity	4,329		4,265
Total liabilities and equity	8,353		7,933
Non-Guarantors [Member]
Current Assets
Cash and cash equivalents	372		409	377	346
Trade receivables - third party and affiliates	1,033		1,040
Non-trade receivables, net	606		697
Inventories, net	750		765
Marketable securities, at fair value	0		0
Other assets	46		37
Total current assets	2,807		2,948
Investments in affiliates	828		855
Property, Plant and Equipment, Net	2,393		2,430
Operating Lease, Right-of-Use Asset	151
Deferred income taxes	114		86
Other assets	455		461
Goodwill	676		658
Intangible Assets, Net (Excluding Goodwill)	201		178
Total assets	7,625		7,616
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	904		258
Trade payables - third party and affiliates	581		583
Other liabilities	283		258
Income taxes payable	114		88
Total current liabilities	1,882		1,187
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	121		127
Deferred income taxes	166		157
Uncertain tax positions	154		152
Benefit obligations	304		314
Operating Lease, Liability, Noncurrent	145
Other liabilities	126		138
Total noncurrent liabilities	1,016		888
Total Celanese Corporation stockholders' equity	4,335		5,146
Noncontrolling interests	392		395
Total equity	4,727		5,541
Total liabilities and equity	7,625		7,616
Eliminations [Member]
Current Assets
Cash and cash equivalents	0		0	$ 0	$ 0
Trade receivables - third party and affiliates	(137)		(119)
Non-trade receivables, net	(3,245)		(1,784)
Inventories, net	(57)		(48)
Marketable securities, at fair value	0		0
Other assets	(24)		(31)
Total current assets	(3,463)		(1,982)
Investments in affiliates	(12,181)		(12,877)
Property, Plant and Equipment, Net	0		0
Operating Lease, Right-of-Use Asset	0
Deferred income taxes	(21)		(2)
Other assets	(1,963)		(1,971)
Goodwill	0		0
Intangible Assets, Net (Excluding Goodwill)	0		0
Total assets	(17,628)		(16,832)
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	(2,616)		(1,039)
Trade payables - third party and affiliates	(137)		(120)
Other liabilities	(148)		(270)
Income taxes payable	(506)		(507)
Total current liabilities	(3,407)		(1,936)
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	(1,934)		(1,940)
Deferred income taxes	(21)		(2)
Uncertain tax positions	0		0
Benefit obligations	0		0
Operating Lease, Liability, Noncurrent	0
Other liabilities	(39)		(40)
Total noncurrent liabilities	(1,994)		(1,982)
Total Celanese Corporation stockholders' equity	(12,227)		(12,914)
Noncontrolling interests	0		0
Total equity	(12,227)		(12,914)
Total liabilities and equity	$ (17,628)		$ (16,832)

[1] There were $0 million of accumulated impairment losses as of March 31, 2019.