Marketable Securities, at Fair Value (Schedule of Available-for-sale Securities) (Details) (Mutual Funds [Member], USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Mutual Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 44	$ 53
Gross unrealized gain	0	0
Gross unrealized loss	0	0
Fair value	$ 44	$ 53

Amount of accumulated pre-tax unrealized gain before deducting pre-tax unrealized loss on investments in available-for-sale securities inpacting investments.

No definition available.

+ Details

Name:	ce_AvailableForSaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments
Namespace Prefix:	ce_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of accumulated pre-tax unrealized loss before deducting pre-tax unrealized gain on investments in available-for-sale securities impacting investments.

+ References

No definition available.

+ Details

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

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.2)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesAmortizedCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in debt and equity securities categorized neither as trading securities nor held-to-maturity securities and intended be sold or mature one year or operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26626-111562

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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