Environmental (German Infraservs Narrative) (Details)	Dec. 31, 2017
Environmental Remediation Obligations [Abstract]
Demerger obligations indemnification percentage	66.66%
Other demerger obligations indemnification percentage	66.66%

Other demerger obligations indemnification percentage.

No definition available.

Name:	ce_OtherDemergerObligationsIndemnificationPercentage
Namespace Prefix:	ce_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant