v3.26.1
Cover
12 Months Ended
Dec. 31, 2025
Document Information [Line Items]  
Document Type 11-K
Entity Registrant Name MERCK & CO., INC.
Entity Central Index Key 0000310158
Amendment Flag false
EBP 004  
Document Information [Line Items]  
Document Type 11-K
Entity tax identification number 22-1918501
Plan number 004
Entity Registrant Name MERCK & CO., INC.
Entity Central Index Key 0000310158
Amendment Flag false