Legal Proceedings (Details)	3 Months Ended	9 Months Ended	0 Months Ended
Sep. 30, 2012 US_Attorney_Office	Sep. 30, 2013 Defendant	Jun. 07, 2013 revlimid royalty	Jun. 07, 2013 pomalyst royalty
Product Liability Contingency [Line Items]
Number of other U.S. Attorney offices conducting investigations	2
Royalty rate			1.00%	2.50%
Number of defendants in suit		3

The number of other U.S. Attorney offices conducting investigations.

No definition available.

Name:	celg_NumberOfOtherUSAttorneyOfficesConductingInvestigations
Namespace Prefix:	celg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration