XML 131 R110.htm IDEA: XBRL DOCUMENT v3.22.0.1

Segment Reporting - Sales of Company's Products (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Sales	$ 48,704	$ 41,518	$ 39,121
Revenue related to the sale of the marketing rights	185
Operating Segments
Segment Reporting Information [Line Items]
Sales	48,322	41,336	38,668
Operating Segments | Pharmaceutical segment
Segment Reporting Information [Line Items]
Sales	42,754	36,610	34,100
Operating Segments | Pharmaceutical segment | Keytruda
Segment Reporting Information [Line Items]
Sales	17,186	14,380	11,084
Operating Segments | Pharmaceutical segment | Alliance revenue - Lynparza
Segment Reporting Information [Line Items]
Sales	989	725	444
Operating Segments | Pharmaceutical segment | Alliance revenue - Lenvima
Segment Reporting Information [Line Items]
Sales	704	580	404
Operating Segments | Pharmaceutical segment | Gardasil/Gardasil 9
Segment Reporting Information [Line Items]
Sales	5,673	3,938	3,737
Operating Segments | Pharmaceutical segment | ProQuad/M-M-R II/Varivax
Segment Reporting Information [Line Items]
Sales	2,135	1,878	2,275
Operating Segments | Pharmaceutical segment | Pneumovax 23
Segment Reporting Information [Line Items]
Sales	893	1,087	926
Operating Segments | Pharmaceutical segment | RotaTeq
Segment Reporting Information [Line Items]
Sales	807	797	791
Operating Segments | Pharmaceutical segment | Vaqta
Segment Reporting Information [Line Items]
Sales	179	170	238
Operating Segments | Pharmaceutical segment | Bridion
Segment Reporting Information [Line Items]
Sales	1,532	1,198	1,131
Operating Segments | Pharmaceutical segment | Prevymis
Segment Reporting Information [Line Items]
Sales	370	281	165
Operating Segments | Pharmaceutical segment | Primaxin
Segment Reporting Information [Line Items]
Sales	259	251	273
Operating Segments | Pharmaceutical segment | Noxafil
Segment Reporting Information [Line Items]
Sales	259	329	662
Operating Segments | Pharmaceutical segment | Cancidas
Segment Reporting Information [Line Items]
Sales	212	213	249
Operating Segments | Pharmaceutical segment | Invanz
Segment Reporting Information [Line Items]
Sales	202	211	263
Operating Segments | Pharmaceutical segment | Zerbaxa
Segment Reporting Information [Line Items]
Sales	(1)	130	121
Operating Segments | Pharmaceutical segment | Simponi
Segment Reporting Information [Line Items]
Sales	825	838	830
Operating Segments | Pharmaceutical segment | Remicade
Segment Reporting Information [Line Items]
Sales	299	330	411
Operating Segments | Pharmaceutical segment | Belsomra
Segment Reporting Information [Line Items]
Sales	318	327	306
Operating Segments | Pharmaceutical segment | Molnupiravir
Segment Reporting Information [Line Items]
Sales	952	0	0
Operating Segments | Pharmaceutical segment | Isentress/Isentress HD
Segment Reporting Information [Line Items]
Sales	769	857	975
Operating Segments | Pharmaceutical segment | Alliance revenue - Adempas/Verquvo
Segment Reporting Information [Line Items]
Sales	342	281	204
Operating Segments | Pharmaceutical segment | Adempas
Segment Reporting Information [Line Items]
Sales	252	220	215
Operating Segments | Pharmaceutical segment | Januvia
Segment Reporting Information [Line Items]
Sales	3,324	3,306	3,482
Operating Segments | Pharmaceutical segment | Janumet
Segment Reporting Information [Line Items]
Sales	1,964	1,971	2,041
Operating Segments | Pharmaceutical segment | Other pharmaceutical
Segment Reporting Information [Line Items]
Sales	2,310	2,312	2,873
Operating Segments | Animal Health
Segment Reporting Information [Line Items]
Sales	5,568	4,703	4,393
Operating Segments | Animal Health | Livestock
Segment Reporting Information [Line Items]
Sales	3,295	2,939	2,784
Operating Segments | Animal Health | Companion Animals
Segment Reporting Information [Line Items]
Sales	2,273	1,764	1,609
Operating Segments | Other segments
Segment Reporting Information [Line Items]
Sales	0	23	175
Other
Segment Reporting Information [Line Items]
Sales	382	182	453
United States
Segment Reporting Information [Line Items]
Sales	22,425	19,588	18,420
United States | Operating Segments
Segment Reporting Information [Line Items]
Sales	22,159	19,517	18,334
United States | Operating Segments | Pharmaceutical segment
Segment Reporting Information [Line Items]
Sales	20,401	18,010	16,854
United States | Operating Segments | Pharmaceutical segment | Keytruda
Segment Reporting Information [Line Items]
Sales	9,765	8,352	6,305
United States | Operating Segments | Pharmaceutical segment | Alliance revenue - Lynparza
Segment Reporting Information [Line Items]
Sales	515	417	269
United States | Operating Segments | Pharmaceutical segment | Alliance revenue - Lenvima
Segment Reporting Information [Line Items]
Sales	417	359	239
United States | Operating Segments | Pharmaceutical segment | Gardasil/Gardasil 9
Segment Reporting Information [Line Items]
Sales	1,881	1,755	1,831
United States | Operating Segments | Pharmaceutical segment | ProQuad/M-M-R II/Varivax
Segment Reporting Information [Line Items]
Sales	1,629	1,378	1,683
United States | Operating Segments | Pharmaceutical segment | Pneumovax 23
Segment Reporting Information [Line Items]
Sales	547	727	679
United States | Operating Segments | Pharmaceutical segment | RotaTeq
Segment Reporting Information [Line Items]
Sales	473	486	506
United States | Operating Segments | Pharmaceutical segment | Vaqta
Segment Reporting Information [Line Items]
Sales	100	103	130
United States | Operating Segments | Pharmaceutical segment | Bridion
Segment Reporting Information [Line Items]
Sales	762	583	533
United States | Operating Segments | Pharmaceutical segment | Prevymis
Segment Reporting Information [Line Items]
Sales	153	119	84
United States | Operating Segments | Pharmaceutical segment | Primaxin
Segment Reporting Information [Line Items]
Sales	2	2	2
United States | Operating Segments | Pharmaceutical segment | Noxafil
Segment Reporting Information [Line Items]
Sales	60	42	282
United States | Operating Segments | Pharmaceutical segment | Cancidas
Segment Reporting Information [Line Items]
Sales	4	7	6
United States | Operating Segments | Pharmaceutical segment | Invanz
Segment Reporting Information [Line Items]
Sales	(5)	9	30
United States | Operating Segments | Pharmaceutical segment | Zerbaxa
Segment Reporting Information [Line Items]
Sales	4	74	63
United States | Operating Segments | Pharmaceutical segment | Simponi
Segment Reporting Information [Line Items]
Sales	0	0	0
United States | Operating Segments | Pharmaceutical segment | Remicade
Segment Reporting Information [Line Items]
Sales	0	0	0
United States | Operating Segments | Pharmaceutical segment | Belsomra
Segment Reporting Information [Line Items]
Sales	78	81	92
United States | Operating Segments | Pharmaceutical segment | Molnupiravir
Segment Reporting Information [Line Items]
Sales	632	0	0
United States | Operating Segments | Pharmaceutical segment | Isentress/Isentress HD
Segment Reporting Information [Line Items]
Sales	294	326	398
United States | Operating Segments | Pharmaceutical segment | Alliance revenue - Adempas/Verquvo
Segment Reporting Information [Line Items]
Sales	312	259	194
United States | Operating Segments | Pharmaceutical segment | Adempas
Segment Reporting Information [Line Items]
Sales	0	0	0
United States | Operating Segments | Pharmaceutical segment | Januvia
Segment Reporting Information [Line Items]
Sales	1,404	1,470	1,724
United States | Operating Segments | Pharmaceutical segment | Janumet
Segment Reporting Information [Line Items]
Sales	367	477	589
United States | Operating Segments | Pharmaceutical segment | Other pharmaceutical
Segment Reporting Information [Line Items]
Sales	1,007	984	1,215
United States | Operating Segments | Animal Health
Segment Reporting Information [Line Items]
Sales	1,758	1,484	1,306
United States | Operating Segments | Animal Health | Livestock
Segment Reporting Information [Line Items]
Sales	667	612	582
United States | Operating Segments | Animal Health | Companion Animals
Segment Reporting Information [Line Items]
Sales	1,091	872	724
United States | Operating Segments | Other segments
Segment Reporting Information [Line Items]
Sales	0	23	174
United States | Other
Segment Reporting Information [Line Items]
Sales	266	71	86
Int’l
Segment Reporting Information [Line Items]
Sales	26,279	21,930	20,701
Int’l | Operating Segments
Segment Reporting Information [Line Items]
Sales	26,163	21,819	20,333
Int’l | Operating Segments | Pharmaceutical segment
Segment Reporting Information [Line Items]
Sales	22,353	18,600	17,246
Int’l | Operating Segments | Pharmaceutical segment | Keytruda
Segment Reporting Information [Line Items]
Sales	7,421	6,028	4,779
Int’l | Operating Segments | Pharmaceutical segment | Alliance revenue - Lynparza
Segment Reporting Information [Line Items]
Sales	473	308	176
Int’l | Operating Segments | Pharmaceutical segment | Alliance revenue - Lenvima
Segment Reporting Information [Line Items]
Sales	287	220	165
Int’l | Operating Segments | Pharmaceutical segment | Gardasil/Gardasil 9
Segment Reporting Information [Line Items]
Sales	3,792	2,184	1,905
Int’l | Operating Segments | Pharmaceutical segment | ProQuad/M-M-R II/Varivax
Segment Reporting Information [Line Items]
Sales	506	500	592
Int’l | Operating Segments | Pharmaceutical segment | Pneumovax 23
Segment Reporting Information [Line Items]
Sales	346	359	247
Int’l | Operating Segments | Pharmaceutical segment | RotaTeq
Segment Reporting Information [Line Items]
Sales	334	311	284
Int’l | Operating Segments | Pharmaceutical segment | Vaqta
Segment Reporting Information [Line Items]
Sales	79	67	108
Int’l | Operating Segments | Pharmaceutical segment | Bridion
Segment Reporting Information [Line Items]
Sales	770	615	598
Int’l | Operating Segments | Pharmaceutical segment | Prevymis
Segment Reporting Information [Line Items]
Sales	218	162	81
Int’l | Operating Segments | Pharmaceutical segment | Primaxin
Segment Reporting Information [Line Items]
Sales	258	248	271
Int’l | Operating Segments | Pharmaceutical segment | Noxafil
Segment Reporting Information [Line Items]
Sales	199	287	380
Int’l | Operating Segments | Pharmaceutical segment | Cancidas
Segment Reporting Information [Line Items]
Sales	208	207	242
Int’l | Operating Segments | Pharmaceutical segment | Invanz
Segment Reporting Information [Line Items]
Sales	207	202	233
Int’l | Operating Segments | Pharmaceutical segment | Zerbaxa
Segment Reporting Information [Line Items]
Sales	(5)	56	58
Int’l | Operating Segments | Pharmaceutical segment | Simponi
Segment Reporting Information [Line Items]
Sales	825	838	830
Int’l | Operating Segments | Pharmaceutical segment | Remicade
Segment Reporting Information [Line Items]
Sales	299	330	411
Int’l | Operating Segments | Pharmaceutical segment | Belsomra
Segment Reporting Information [Line Items]
Sales	241	247	214
Int’l | Operating Segments | Pharmaceutical segment | Molnupiravir
Segment Reporting Information [Line Items]
Sales	320	0	0
Int’l | Operating Segments | Pharmaceutical segment | Isentress/Isentress HD
Segment Reporting Information [Line Items]
Sales	474	531	576
Int’l | Operating Segments | Pharmaceutical segment | Alliance revenue - Adempas/Verquvo
Segment Reporting Information [Line Items]
Sales	30	22	10
Int’l | Operating Segments | Pharmaceutical segment | Adempas
Segment Reporting Information [Line Items]
Sales	252	220	215
Int’l | Operating Segments | Pharmaceutical segment | Januvia
Segment Reporting Information [Line Items]
Sales	1,920	1,836	1,758
Int’l | Operating Segments | Pharmaceutical segment | Janumet
Segment Reporting Information [Line Items]
Sales	1,597	1,494	1,452
Int’l | Operating Segments | Pharmaceutical segment | Other pharmaceutical
Segment Reporting Information [Line Items]
Sales	1,302	1,328	1,661
Int’l | Operating Segments | Animal Health
Segment Reporting Information [Line Items]
Sales	3,810	3,219	3,086
Int’l | Operating Segments | Animal Health | Livestock
Segment Reporting Information [Line Items]
Sales	2,628	2,327	2,201
Int’l | Operating Segments | Animal Health | Companion Animals
Segment Reporting Information [Line Items]
Sales	1,182	892	885
Int’l | Operating Segments | Other segments
Segment Reporting Information [Line Items]
Sales	0	0	1
Int’l | Other
Segment Reporting Information [Line Items]
Sales	$ 116	$ 111	$ 368

X

- Definition

The cash inflow from disposal of asset without physical form usually arising from contractual or other legal rights, excluding goodwill.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3179-108585

+ Details

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

X

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=123596393&loc=d3e14064-108612

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iv))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iv))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(A))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9031-108599

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(i))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(i))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8906-108599

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(5))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9038-108599

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iii)(A))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(5))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9054-108599

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 235
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-05(b)(2))
-URI http://asc.fasb.org/extlink&oid=120399901&loc=d3e537907-122884

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(B))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

Reference 22: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(ii))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(1))
-URI http://asc.fasb.org/extlink&oid=123367319&loc=SL114868664-224227

+ Details

Name:	us-gaap_Revenues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

No definition available.

+ Details

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

X

- Details

Name:	srt_ConsolidationItemsAxis=us-gaap_OperatingSegmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=mrk_PharmaceuticalsegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

Name:	srt_ProductOrServiceAxis=mrk_GardasilGardasil9Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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

X

- Details

Name:	srt_ProductOrServiceAxis=mrk_Pneumovax23Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=mrk_AnimalHealthsegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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

X

- Details

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

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=us-gaap_AllOtherSegmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_ConsolidationItemsAxis=us-gaap_CorporateNonSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_StatementGeographicalAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_StatementGeographicalAxis=mrk_InternationalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: