Consolidating Guarantor Financial Information (Schedule of Consolidating Balance Sheet) (Details) - USD ($) $ in Millions	Mar. 31, 2020		Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Current Assets
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 570		$ 463	$ 441	$ 439
Trade receivables - third party and affiliates	853		850
Non-trade receivables, net	307		331
Inventories, net	1,036		1,038
Marketable securities	38		40
Other assets	51		43
Total current assets	2,855		2,765
Investments in affiliates	981		975
Property, Plant and Equipment, Net	3,678		3,713
Operating Lease, Right-of-Use Asset	201		203
Deferred income taxes	91		96
Other assets	381		338
Goodwill	1,056	[1]	1,074
Intangible Assets, Net (Excluding Goodwill)	302		312
Total assets	9,545		9,476
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	749		496
Trade payables - third party and affiliates	724		780
Other liabilities	422		461
Income taxes payable	33		17
Total current liabilities	1,928		1,754
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	3,356		3,409
Deferred income taxes	258		257
Uncertain tax positions	161		165
Benefit obligations	568		589
Operating Lease, Liability, Noncurrent	175		181
Other liabilities	263		223
Total noncurrent liabilities	4,781		4,824
Total Celanese Corporation stockholders' equity	2,448		2,507	3,047
Noncontrolling interests	388		391
Total equity	2,836		2,898	3,439
Total liabilities and equity	9,545		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	57		56
Inventories, net	0		0
Marketable securities	0		0
Other assets	0		0
Total current assets	57		56
Investments in affiliates	4,236		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	4,293		4,120
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	1,845		1,596
Trade payables - third party and affiliates	0		17
Other liabilities	0		0
Income taxes payable	0		0
Total current liabilities	1,845		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	2,448		2,507
Noncontrolling interests	0		0
Total equity	2,448		2,507
Total liabilities and equity	4,293		4,120
Issuer [Member]
Current Assets
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	20		0	0	0
Trade receivables - third party and affiliates	0		0
Non-trade receivables, net	1,521		1,188
Inventories, net	0		0
Marketable securities	0		0
Other assets	43		36
Total current assets	1,584		1,224
Investments in affiliates	5,375		5,217
Property, Plant and Equipment, Net	0		0
Operating Lease, Right-of-Use Asset	0		0
Deferred income taxes	0		0
Other assets	1,683		1,661
Goodwill	0		0
Intangible Assets, Net (Excluding Goodwill)	0		0
Total assets	8,642		8,102
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	720		374
Trade payables - third party and affiliates	0		0
Other liabilities	70		49
Income taxes payable	0		0
Total current liabilities	790		423
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	3,516		3,565
Deferred income taxes	7		3
Uncertain tax positions	2		0
Benefit obligations	0		0
Operating Lease, Liability, Noncurrent	0		0
Other liabilities	91		47
Total noncurrent liabilities	3,616		3,615
Total Celanese Corporation stockholders' equity	4,236		4,064
Noncontrolling interests	0		0
Total equity	4,236		4,064
Total liabilities and equity	8,642		8,102
Subsidiary Guarantors [Member]
Current Assets
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	21		16	69	30
Trade receivables - third party and affiliates	131		122
Non-trade receivables, net	2,136		1,925
Inventories, net	366		360
Marketable securities	22		24
Other assets	14		11
Total current assets	2,690		2,458
Investments in affiliates	4,316		4,206
Property, Plant and Equipment, Net	1,476		1,461
Operating Lease, Right-of-Use Asset	51		50
Deferred income taxes	0		0
Other assets	224		195
Goodwill	399		399
Intangible Assets, Net (Excluding Goodwill)	123		125
Total assets	9,279		8,894
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	1,384		1,089
Trade payables - third party and affiliates	299		333
Other liabilities	162		188
Income taxes payable	436		439
Total current liabilities	2,281		2,049
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	1,677		1,677
Deferred income taxes	101		101
Uncertain tax positions	0		0
Benefit obligations	252		257
Operating Lease, Liability, Noncurrent	41		40
Other liabilities	90		93
Total noncurrent liabilities	2,161		2,168
Total Celanese Corporation stockholders' equity	4,837		4,677
Noncontrolling interests	0		0
Total equity	4,837		4,677
Total liabilities and equity	9,279		8,894
Non-Guarantors [Member]
Current Assets
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	529		447	372	409
Trade receivables - third party and affiliates	866		851
Non-trade receivables, net	786		743
Inventories, net	725		725
Marketable securities	16		16
Other assets	55		38
Total current assets	2,977		2,820
Investments in affiliates	851		841
Property, Plant and Equipment, Net	2,202		2,252
Operating Lease, Right-of-Use Asset	150		153
Deferred income taxes	96		101
Other assets	435		445
Goodwill	657		675
Intangible Assets, Net (Excluding Goodwill)	179		187
Total assets	7,547		7,474
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	361		385
Trade payables - third party and affiliates	569		553
Other liabilities	383		397
Income taxes payable	97		80
Total current liabilities	1,410		1,415
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	90		101
Deferred income taxes	155		158
Uncertain tax positions	169		169
Benefit obligations	316		332
Operating Lease, Liability, Noncurrent	134		140
Other liabilities	115		118
Total noncurrent liabilities	979		1,018
Total Celanese Corporation stockholders' equity	4,770		4,650
Noncontrolling interests	388		391
Total equity	5,158		5,041
Total liabilities and equity	7,547		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	(144)		(123)
Non-trade receivables, net	(4,193)		(3,581)
Inventories, net	(55)		(47)
Marketable securities	0		0
Other assets	(61)		(42)
Total current assets	(4,453)		(3,793)
Investments in affiliates	(13,797)		(13,353)
Property, Plant and Equipment, Net	0		0
Operating Lease, Right-of-Use Asset	0		0
Deferred income taxes	(5)		(5)
Other assets	(1,961)		(1,963)
Goodwill	0		0
Intangible Assets, Net (Excluding Goodwill)	0		0
Total assets	(20,216)		(19,114)
Current Liabilities
Short-term borrowings and current installments of long-term debt - third party and affiliates	(3,561)		(2,948)
Trade payables - third party and affiliates	(144)		(123)
Other liabilities	(193)		(173)
Income taxes payable	(500)		(502)
Total current liabilities	(4,398)		(3,746)
Noncurrent Liabilities
Long-term debt, net of unamortized deferred financing costs	(1,927)		(1,934)
Deferred income taxes	(5)		(5)
Uncertain tax positions	(10)		(4)
Benefit obligations	0		0
Operating Lease, Liability, Noncurrent	0		1
Other liabilities	(33)		(35)
Total noncurrent liabilities	(1,975)		(1,977)
Total Celanese Corporation stockholders' equity	(13,843)		(13,391)
Noncontrolling interests	0		0
Total equity	(13,843)		(13,391)
Total liabilities and equity	$ (20,216)		$ (19,114)

[1] There were $0 million of accumulated impairment losses as of March 31, 2020.