Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2020	Jan. 28, 2021	Jun. 30, 2020
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	001-32410
Entity Registrant Name	CELANESE CORPORATION
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	98-0420726
Entity Address, Address Line One	222 W. Las Colinas Blvd., Suite 900N
Entity Address, City or Town	Irving
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	75039-5421
City Area Code	972
Local Phone Number	443-4000
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Small Reporting Company	false
Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 10,196,052,077
Entity Common Stock, Shares Outstanding		114,173,336
Entity Central Index Key	0001306830
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false
Common Stock [Member]
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	CE
Security Exchange Name	NYSE
Senior Unsecured Notes Due 2023 [Member]
Entity Information [Line Items]
Title of 12(b) Security	1.125% Senior Notes due 2023
Trading Symbol	CE /23
Security Exchange Name	NYSE
Senior Unsecured Notes Due 2025 [Member]
Entity Information [Line Items]
Title of 12(b) Security	1.250% Senior Notes due 2025
Trading Symbol	CE /25
Security Exchange Name	NYSE
Senior Unsecured Notes Due 2027 [Member]
Entity Information [Line Items]
Title of 12(b) Security	2.125% Senior Notes due 2027
Trading Symbol	CE /27
Security Exchange Name	NYSE