Collaborative Arrangement, Rights and Obligations, Contingent Milestone Proceeds

No definition available.

Name:	mrk_CollaborativeArrangementRightsAndObligationsContingentMilestoneProceeds
Namespace Prefix:	mrk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Royalty Rate, Deduction, Percentage

+ References

No definition available.

+ Details

Name:	mrk_RoyaltyRateDeductionPercentage
Namespace Prefix:	mrk_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Royalty Rate, Percentage

+ References

No definition available.

+ Details

Name:	mrk_RoyaltyRatePercentage
Namespace Prefix:	mrk_
Data Type:	dtr-types1: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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 808
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479402/808-10-50-1

+ Details

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

- Definition

Amount of revenue from collaborative arrangement. Excludes revenue from contract with customer under Topic 606.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 808
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479402/808-10-50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 3
-SubTopic 10
-Topic 808
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479428/808-10-45-3

+ Details

Name:	us-gaap_RevenueFromCollaborativeArrangementExcludingRevenueFromContractWithCustomer
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	srt_CounterpartyNameAxis=mrk_BristolMyersSquibbCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=us-gaap_LicensingAgreementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ContingentConsiderationByTypeAxis=mrk_SalesBasedMilestonesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=us-gaap_CollaborativeArrangementTransactionWithPartyToCollaborativeArrangementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Collaborative Arrangements - Bristol Meyers Squibb Company - Narrative (Details) - Bristol Myers Squibb Company - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Licensing Agreements
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty rate, deduction	0.50
Licensing Agreements \| Sales-Based Milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contingent proceeds collaborative arrangement	$ 80
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue from collaborative arrangement	$ 71	$ 43
Minimum \| Licensing Agreements
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty rate	20.00%
Maximum \| Licensing Agreements
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty rate	24.00%