Management Compensation Plans Management Compensation Plans (Schedule of Weighted-average Discount Rate for RSUs) (Details)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Holding period discount	30.00%	30.00%	30.00%

RSU Holding Period, Weighted-average Discount Rate Percent.

No definition available.

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