Name:	regn_Amountofmilestonepaymentthatmaybereceivedrelatingtomarketingapproval
Namespace Prefix:	regn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The amount of non-refundable payment received in relation to the collaboration agreement. May be an up-front payment, termination payment, and/or payment made in connection to an amendment to the agreement.

No definition available.

Name:	regn_Amountofnonrefundablepaymentreceivedforcollaborationagreement
Namespace Prefix:	regn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Future development milestone payment the Company is eligible to receive from Bayer HealthCare under the development plan.

No definition available.

Name:	regn_Futuredevelopmentmilestonepayment
Namespace Prefix:	regn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Number of development milestone payments the Company received

No definition available.

Name:	regn_NumberofdevelopmentmilestonepaymentstheCompanyreceived
Namespace Prefix:	regn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

potential opt-in payment the Company is eligible to receive from Bayer HealthCare.

No definition available.

Name:	regn_Optinpayment
Namespace Prefix:	regn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Percentage of development cost for the territory outside the United States to be paid for under the collaboration.

No definition available.

Name:	regn_PercentageofdevelopmentcostfortheterritoryoutsidetheUnitedStatestobepaidforunderthecollaboration
Namespace Prefix:	regn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of development milestone payments Bayer HealthCare is obligated to reimburse the Company for payments that the Company makes to Sanofi related to the Company's acquisition of rights to antibodies targeting the PDGF family of receptors.

No definition available.

Name:	regn_Percentageofdevelopmentmilestonepaymentstobereimbursed
Namespace Prefix:	regn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of global development cost to be paid by the collaboration partner under the collaboration

No definition available.

Name:	regn_Percentageofglobaldevelopmentcosttobepaidbythecollaborationpartnerunderthecollaboration
Namespace Prefix:	regn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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

Amount of deferred revenue recognized for transactions arising during the current reporting period. Deferred revenue is a liability as of the balance sheet date related to a revenue producing activity for which revenue has not yet been recognized. Generally, an Entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 13.A.4(a).Q1)

-URI http://asc.fasb.org/extlink&oid=27012821&loc=d3e214044-122780

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

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 13

-Section A