Consolidating Guarantor Financial Information (Schedule of Consolidating Balance Sheet) (Details) - USD ($) $ in Millions	Jun. 30, 2020		Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Current Assets
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 539		$ 463	$ 491	$ 439
Trade receivables - third party and affiliates	729		850
Non-trade receivables, net	312		331
Inventories, net	1,031		1,038
Marketable securities	36		40
Other assets	62		43
Total current assets	2,709		2,765
Investments in affiliates	957		975
Property, Plant and Equipment, Net	3,725		3,713
Operating Lease, Right-of-Use Asset	201		203
Deferred income taxes	100		96
Other assets	399		338
Goodwill	1,098	[1]	1,074
Intangible Assets, Net (Excluding Goodwill)	317		312
Total assets	9,506		9,476
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	1,045		496
Trade payables - third party and affiliates	599		780
Other liabilities	572		461
Income taxes payable	46		17
Total current liabilities	2,262		1,754
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	2,989		3,409
Deferred income taxes	256		257
Uncertain tax positions	189		165
Benefit obligations	579		589
Operating Lease, Liability, Noncurrent	183		181
Other liabilities	179		223
Total noncurrent liabilities	4,375		4,824
Total Celanese Corporation stockholders' equity	2,487		2,507	2,864
Noncontrolling interests	382		391
Total equity	2,869		2,898	3,254
Total liabilities and equity	9,506		9,476
Parent Guarantor [Member]
Current Assets
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	0		0	0	0
Trade receivables - third party and affiliates	0		0
Non-trade receivables, net	58		56
Inventories, net	0		0
Marketable securities	0		0
Other assets	0		0
Total current assets	58		56
Investments in affiliates	4,350		4,064
Property, Plant and Equipment, Net	0		0
Operating Lease, Right-of-Use Asset	0		0
Deferred income taxes	0		0
Other assets	0		0
Goodwill	0		0
Intangible Assets, Net (Excluding Goodwill)	0		0
Total assets	4,408		4,120
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	1,921		1,596
Trade payables - third party and affiliates	0		17
Other liabilities	0		0
Income taxes payable	0		0
Total current liabilities	1,921		1,613
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		0
Other liabilities	0		0
Total noncurrent liabilities	0		0
Total Celanese Corporation stockholders' equity	2,487		2,507
Noncontrolling interests	0		0
Total equity	2,487		2,507
Total liabilities and equity	4,408		4,120
Issuer [Member]
Current Assets
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	0		0	0	0
Trade receivables - third party and affiliates	0		0
Non-trade receivables, net	2,999		1,188
Inventories, net	0		0
Marketable securities	0		0
Other assets	25		36
Total current assets	3,024		1,224
Investments in affiliates	5,515		5,217
Property, Plant and Equipment, Net	0		0
Operating Lease, Right-of-Use Asset	0		0
Deferred income taxes	0		0
Other assets	22		1,661
Goodwill	0		0
Intangible Assets, Net (Excluding Goodwill)	0		0
Total assets	8,561		8,102
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	1,192		374
Trade payables - third party and affiliates	0		0
Other liabilities	136		49
Income taxes payable	0		0
Total current liabilities	1,328		423
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	2,881		3,565
Deferred income taxes	0		3
Uncertain tax positions	2		0
Benefit obligations	0		0
Operating Lease, Liability, Noncurrent	0		0
Other liabilities	0		47
Total noncurrent liabilities	2,883		3,615
Total Celanese Corporation stockholders' equity	4,350		4,064
Noncontrolling interests	0		0
Total equity	4,350		4,064
Total liabilities and equity	8,561		8,102
Subsidiary Guarantors [Member]
Current Assets
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	28		16	51	30
Trade receivables - third party and affiliates	146		122
Non-trade receivables, net	2,103		1,925
Inventories, net	381		360
Marketable securities	21		24
Other assets	27		11
Total current assets	2,706		2,458
Investments in affiliates	4,421		4,206
Property, Plant and Equipment, Net	1,501		1,461
Operating Lease, Right-of-Use Asset	49		50
Deferred income taxes	0		0
Other assets	228		195
Goodwill	398		399
Intangible Assets, Net (Excluding Goodwill)	121		125
Total assets	9,424		8,894
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	3,077		1,089
Trade payables - third party and affiliates	270		333
Other liabilities	169		188
Income taxes payable	475		439
Total current liabilities	3,991		2,049
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	26		1,677
Deferred income taxes	97		101
Uncertain tax positions	0		0
Benefit obligations	248		257
Operating Lease, Liability, Noncurrent	40		40
Other liabilities	93		93
Total noncurrent liabilities	504		2,168
Total Celanese Corporation stockholders' equity	4,929		4,677
Noncontrolling interests	0		0
Total equity	4,929		4,677
Total liabilities and equity	9,424		8,894
Non-Guarantors [Member]
Current Assets
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	511		447	440	409
Trade receivables - third party and affiliates	732		851
Non-trade receivables, net	1,126		743
Inventories, net	729		725
Marketable securities	15		16
Other assets	38		38
Total current assets	3,151		2,820
Investments in affiliates	824		841
Property, Plant and Equipment, Net	2,224		2,252
Operating Lease, Right-of-Use Asset	152		153
Deferred income taxes	102		101
Other assets	159		445
Goodwill	700		675
Intangible Assets, Net (Excluding Goodwill)	196		187
Total assets	7,508		7,474
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	231		385
Trade payables - third party and affiliates	478		553
Other liabilities	392		397
Income taxes payable	76		80
Total current liabilities	1,177		1,415
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	82		101
Deferred income taxes	161		158
Uncertain tax positions	174		169
Benefit obligations	331		332
Operating Lease, Liability, Noncurrent	143		140
Other liabilities	119		118
Total noncurrent liabilities	1,010		1,018
Total Celanese Corporation stockholders' equity	4,939		4,650
Noncontrolling interests	382		391
Total equity	5,321		5,041
Total liabilities and equity	7,508		7,474
Eliminations [Member]
Current Assets
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	0		0	$ 0	$ 0
Trade receivables - third party and affiliates	(149)		(123)
Non-trade receivables, net	(5,974)		(3,581)
Inventories, net	(79)		(47)
Marketable securities	0		0
Other assets	(28)		(42)
Total current assets	(6,230)		(3,793)
Investments in affiliates	(14,153)		(13,353)
Property, Plant and Equipment, Net	0		0
Operating Lease, Right-of-Use Asset	0		0
Deferred income taxes	(2)		(5)
Other assets	(10)		(1,963)
Goodwill	0		0
Intangible Assets, Net (Excluding Goodwill)	0		0
Total assets	(20,395)		(19,114)
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	(5,376)		(2,948)
Trade payables - third party and affiliates	(149)		(123)
Other liabilities	(125)		(173)
Income taxes payable	(505)		(502)
Total current liabilities	(6,155)		(3,746)
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	0		(1,934)
Deferred income taxes	(2)		(5)
Uncertain tax positions	13		(4)
Benefit obligations	0		0
Operating Lease, Liability, Noncurrent	0		1
Other liabilities	(33)		(35)
Total noncurrent liabilities	(22)		(1,977)
Total Celanese Corporation stockholders' equity	(14,218)		(13,391)
Noncontrolling interests	0		0
Total equity	(14,218)		(13,391)
Total liabilities and equity	$ (20,395)		$ (19,114)

[1] There were $0 million of accumulated impairment losses as of June 30, 2020.