Consolidating Guarantor Financial Information (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2015
Consolidating Guarantor Financial Information [Abstract]
Issuer and subsidiary guarantors, ownership percentage	100.00%
Interest Allocated To Subsidiary Guarantor		$ 54

Equity Method Investments Ownership Percentage of Subsidiary.

No definition available.

Name:	ce_EquityMethodInvestmentsOwnershipPercentageOfSubsidiary
Namespace Prefix:	ce_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration