Aggregate upfront and milestone payments made since inception of collaboration agreement.

No definition available.

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Data Type:	xbrli:monetaryItemType
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- Definition

Represents the ratio of co-development and profit share in exchange for a reduction of milestones.

+ References

No definition available.

+ Details

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Namespace Prefix:	celg_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the notice period required to be served before the termination of the agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	celg_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the potential payment that the entity is eligible to pay for certain milestone(s), which may include development, regulatory approval or sales-based milestones under the agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	celg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the potential payment per product that the entity is eligible to pay for certain milestone(s), which may include development, regulatory approval or sales-based milestones under the agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	celg_
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Balance Type:	credit
Period Type:	duration

- Definition

[Table Text Block] for research and development period [Table]

+ References

No definition available.

+ Details

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Upfront payments made under a collaboration agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	celg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Upfront Payments Made, Shares

+ References

No definition available.

+ Details

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Namespace Prefix:	celg_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

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- Definition

This element represents the aggregate carrying amount of all cost-method investments held by the Company. Generally, such investments do not have readily determinable fair values and are not required to be accounted for by the equity method. The carrying amount of such securities equates to cost, adjusted for other-than-temporary impairment. The cost method and lower-of-cost or market, an adaptation of the cost method, is generally followed for most investments in noncontrolled corporations, in some corporate joint ventures, and to a lesser extent in unconsolidated subsidiaries, particularly foreign.

+ References

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

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 18

-Paragraph 5

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 03-1

-Paragraph 22

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 4

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 18

-Paragraph 6

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 325

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6872867&loc=d3e40691-111596

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 18

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

The costs incurred in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, excluding in-process research and development acquired in a business combination consummated during the period. Excludes software research and development, which has a separate concept.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 86

-Paragraph 11

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 730

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6420194&loc=d3e21568-108373

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Research and Development

-URI http://asc.fasb.org/extlink&oid=6523717

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 86

-Paragraph 3

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 2

-Paragraph 8, 12, 13

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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Collaboration Agreements (Details) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended			9 Months Ended							3 Months Ended		9 Months Ended							3 Months Ended	9 Months Ended
	Sep. 30, 2013 USD ($)	Sep. 30, 2012 USD ($)	Sep. 30, 2013 USD ($)	Sep. 30, 2012 USD ($)	Sep. 30, 2013 Equity Securities and Other Assets USD ($)	Sep. 30, 2013 Morphosys USD ($)	Sep. 30, 2013 Morphosys EUR (€)	Sep. 30, 2013 Morphosys Collaborative Arrangement Maximum USD ($)	Sep. 30, 2013 Morphosys Collaborative Arrangement Maximum EUR (€)	Sep. 30, 2013 Acetylon USD ($)	Sep. 30, 2013 Acetylon milestone payments maximum Acetylon Maximum USD ($)	Sep. 30, 2013 Bluebird USD ($)	Mar. 31, 2013 Bluebird Celgene	Mar. 31, 2013 Bluebird	Sep. 30, 2013 research and development payments FORMA USD ($)	Sep. 30, 2013 regulatory approval milestone FORMA USD ($)	Sep. 30, 2013 license payments FORMA USD ($)	Sep. 30, 2013 Forma	Sep. 30, 2013 MorphoSys AG Celgene	Sep. 30, 2013 MorphoSys AG Morphosys	Sep. 30, 2013 Other Collaboration Arrangements USD ($)	Sep. 30, 2013 All Collaboration Agreements Partners USD ($)	Sep. 30, 2013 All Collaboration Agreements Partners USD ($)
Collaboration Agreements Transactions
Potential milestone payments per product												$ 225.0
Co-development and Profit Sharing Ratio Due to Reduction of Milestones													50.00%	50.00%					50.00%	50.00%
Notice period required to be given before termination of agreement						6 months	6 months					90 days
Potential milestone payments								664.5	511.0		1,100.0				200.0	315.0	430.0				373.0
research and development period																		4 years
Upfront payments made						152.1	117.0
Upfront share payments made						797,150	797,150
Aggregate Collaboration Agreement Payments										100.0
Investments in equity or other assets					12.0
Research and development	$ 584.5	$ 441.5	$ 1,495.0	$ 1,250.7																		$ 171.3	$ 348.8