Leases Narrative (Details)	Mar. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Operating lease commitments that have not yet commenced	$ 0
Finance lease commitments that have not yet commenced	$ 0
Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Finance Lease, Renewal Term	1 year
Lessee, Operating Lease, Renewal Term	1 year
Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Finance Lease, Renewal Term	30 years
Lessee, Operating Lease, Renewal Term	30 years

Finance Lease- Lease Not yet Commenced Liabilities

No definition available.

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Namespace Prefix:	ce_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Operating Lease- Lease Not yet Commenced Liabilities

+ References

No definition available.

+ Details

Name:	ce_OperatingLeaseLeaseNotyetCommencedLiabilities
Namespace Prefix:	ce_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Term of lessee's finance lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Details

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- Details

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