XML 95 R58.htm IDEA: XBRL DOCUMENT v3.24.0.1

Restructuring - Charges Activities by Type of Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 933
2024 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	190
2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	743	$ 666	$ 868
Cost of sales | 2024 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 62
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Cost of sales
Cost of sales | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 149	$ 205	$ 160
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Cost of sales	Cost of sales	Cost of sales
Selling, general and administrative | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 122	$ 94	$ 19
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Selling, general and administrative	Selling, general and administrative	Selling, general and administrative
Research and development | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 1	$ 30	$ 28
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Research and development	Research and development	Research and development
Restructuring costs | 2024 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 128
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Restructuring costs
Restructuring costs | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 471	$ 337	$ 661
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Restructuring costs	Restructuring costs	Restructuring costs
Separation Costs
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 454
Separation Costs | 2024 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	115
Separation Costs | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	339	$ 212	$ 451
Separation Costs | Cost of sales | 2024 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 0
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Cost of sales
Separation Costs | Cost of sales | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 0	$ 0	$ 0
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Cost of sales	Cost of sales	Cost of sales
Separation Costs | Selling, general and administrative | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 0	$ 0	$ 0
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Selling, general and administrative	Selling, general and administrative	Selling, general and administrative
Separation Costs | Research and development | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 0	$ 0	$ 0
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Research and development	Research and development	Research and development
Separation Costs | Restructuring costs | 2024 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 115
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Restructuring costs
Separation Costs | Restructuring costs | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 339	$ 212	$ 451
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Restructuring costs	Restructuring costs	Restructuring costs
Accelerated Depreciation
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 140
Accelerated Depreciation | 2024 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	0
Accelerated Depreciation | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	140	$ 120	$ 91
Accelerated Depreciation | Cost of sales | 2024 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 0
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Cost of sales
Accelerated Depreciation | Cost of sales | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 131	$ 72	$ 52
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Cost of sales	Cost of sales	Cost of sales
Accelerated Depreciation | Selling, general and administrative | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 9	$ 19	$ 12
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Selling, general and administrative	Selling, general and administrative	Selling, general and administrative
Accelerated Depreciation | Research and development | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 0	$ 29	$ 27
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Research and development	Research and development	Research and development
Accelerated Depreciation | Restructuring costs | 2024 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 0
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Restructuring costs
Accelerated Depreciation | Restructuring costs | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 0	$ 0	$ 0
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Restructuring costs	Restructuring costs	Restructuring costs
Other Exit Costs
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 339
Other Exit Costs | 2024 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	75
Other Exit Costs | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	264	$ 334	$ 326
Other Exit Costs | Cost of sales | 2024 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 62
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Cost of sales
Other Exit Costs | Cost of sales | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 18	$ 133	$ 108
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Cost of sales	Cost of sales	Cost of sales
Other Exit Costs | Selling, general and administrative | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 113	$ 75	$ 7
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Selling, general and administrative	Selling, general and administrative	Selling, general and administrative
Other Exit Costs | Research and development | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 1	$ 1	$ 1
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Research and development	Research and development	Research and development
Other Exit Costs | Restructuring costs | 2024 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 13
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Restructuring costs
Other Exit Costs | Restructuring costs | 2019 Restructuring Program
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 132	$ 125	$ 210
Restructuring, Incurred Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Restructuring costs	Restructuring costs	Restructuring costs

X

- Definition

Discloses the amount charged against the accrued restructuring reserves, or earnings if not previously accrued, during the period for the specified type of restructuring cost.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482017/420-10-50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b)(1))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479823/420-10-S99-2

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(d))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479823/420-10-S99-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482017/420-10-50-1

+ Details

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

X

- 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 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482017/420-10-50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482017/420-10-50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482017/420-10-50-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479823/420-10-S99-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b)(1))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479823/420-10-S99-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(d))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479823/420-10-S99-2

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482017/420-10-50-1

+ Details

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

X

- Definition

Indicates line item in statement of income or comprehensive income that includes incurred restructuring and related costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482017/420-10-50-1

Reference 2: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479823/420-10-S99-2

+ Details

Name:	us-gaap_RestructuringIncurredCostStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration
Namespace Prefix:	us-gaap_
Data Type:	enum2:enumerationSetItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_RestructuringPlanAxis=mrk_RestructuringProgram2024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RestructuringPlanAxis=mrk_RestructuringProgram2019Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_CostOfSalesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_SellingGeneralAndAdministrativeExpensesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_ResearchAndDevelopmentExpenseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_RestructuringChargesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=us-gaap_EmployeeSeveranceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=mrk_AcceleratedDepreciationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=us-gaap_OtherRestructuringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: