v3.25.2
Cover
Jul. 25, 2025
Document Information [Line Items]  
Document Type 8-K
Amendment Flag false
Document Period End Date Jul. 25, 2025
Entity File Number 1-6571
Entity Registrant Name Merck & Co., Inc.
Entity Central Index Key 0000310158
Entity Tax Identification Number 22-1918501
Entity Incorporation, State or Country Code NJ
Entity Address, Address Line One 126 East Lincoln Avenue
Entity Address, City or Town Rahway
Entity Address, State or Province NJ
Entity Address, Postal Zip Code 07065
City Area Code 732
Local Phone Number 594-4000
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Entity Emerging Growth Company false
Common Stock  
Document Information [Line Items]  
Title of 12(b) Security Common Stock ($0.50 par value)
Trading Symbol MRK
Security Exchange Name NYSE
1.875% Notes due 2026  
Document Information [Line Items]  
Title of 12(b) Security 1.875% Notes due 2026
Trading Symbol MRK/26
Security Exchange Name NYSE
3.250% Notes due 2032  
Document Information [Line Items]  
Title of 12(b) Security 3.250% Notes due 2032
Trading Symbol MRK/32
Security Exchange Name NYSE
2.500% Notes due 2034  
Document Information [Line Items]  
Title of 12(b) Security 2.500% Notes due 2034
Trading Symbol MRK/34
Security Exchange Name NYSE
1.375% Notes due 2036  
Document Information [Line Items]  
Title of 12(b) Security 1.375% Notes due 2036
Trading Symbol MRK 36A
Security Exchange Name NYSE
3.500% Notes due 2037  
Document Information [Line Items]  
Title of 12(b) Security 3.500% Notes due 2037
Trading Symbol MRK/37
Security Exchange Name NYSE
3.700% Notes due 2044  
Document Information [Line Items]  
Title of 12(b) Security 3.700% Notes due 2044
Trading Symbol MRK/44
Security Exchange Name NYSE
3.750% Notes due 2054  
Document Information [Line Items]  
Title of 12(b) Security 3.750% Notes due 2054
Trading Symbol MRK/54
Security Exchange Name NYSE