Payments For Royalties, Percentage

No definition available.

Name:	regn_PaymentsForRoyaltiesPercentage
Namespace Prefix:	regn_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	regn_ResearchCollaborationAndLicensingArrangementsLineItems
Namespace Prefix:	regn_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The maximum royalty rate to be paid to the Company under the agreements.

+ References

No definition available.

+ Details

Name:	regn_RoyaltyRateMaximum
Namespace Prefix:	regn_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The minimum royalty rate to be paid to the Company under the agreements.

+ References

No definition available.

+ Details

Name:	regn_RoyaltyRateMinimum
Namespace Prefix:	regn_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of expense related to royalty payments under a contractual arrangement such as payment for mineral and drilling rights and use of technology or intellectual property.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.3)
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

+ Details

Name:	us-gaap_RoyaltyExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	srt_ProductOrServiceAxis=regn_LIBTAYONetProductSalesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationByPropertyOrProjectAxis=regn_SanofiCollaborationAgreementImmunooncologyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ContractWithCustomerDurationAxis=regn_ThroughDecember312023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ContractWithCustomerDurationAxis=regn_January12024ThroughDecember312026Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	regn_ResearchCollaborationAndLicensingAgreementsAxis=us-gaap_RoyaltyAgreementTermsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Commitments and Contingencies - Research Collaboration and Licensing Agreements Narrative (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Aug. 31, 2018	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Libtayo \| Sanofi Collaboration Agreement, Immuno-oncology \| Through December 31, 2023
Research Collaboration and Licensing Arrangements [Line Items]
Percentage of royalties to be paid	8.00%
Libtayo \| Sanofi Collaboration Agreement, Immuno-oncology \| January 1, 2024 Through December 31, 2026
Research Collaboration and Licensing Arrangements [Line Items]
Percentage of royalties to be paid	2.50%
Agreements with Royalty Provisions
Research Collaboration and Licensing Arrangements [Line Items]
Royalty rate minimum		0.50%
Royalty rate maximum		12.00%
Royalty expense, net of reimbursements from collaborators		$ 84.5	$ 66.9	$ 56.5