v3.25.4
Document and Entity Information
Mar. 12, 2026
Entity Listings [Line Items]  
Document Type 8-K
Document Period End Date Mar. 12, 2026
Entity Registrant Name OMNICOM GROUP INC.
Entity Incorporation State Country Code NY
Entity File Number 1-10551
Entity Tax Identification Number 13-1514814
Entity Address Address Line 1 280 Park Avenue
Entity Address City Or Town New York
Entity Address State Or Province NY
Entity Address Postal Zip Code 10017
City Area Code 212
Local Phone Number 415-3600
Written Communications false
Soliciting Material false
Pre Commencement Tender Offer false
Pre Commencement Issuer Tender Offer false
Entity Emerging Growth Company false
Entity Central Index Key 0000029989
Amendment Flag false
3.850% Senior Notes due 2034 [Member]  
Entity Listings [Line Items]  
Security 12b Title 3.850% Senior Notes due 2034
Trading Symbol OMC/34
Security Exchange Name NYSE
Common Stock, $0.15 Par [Member]  
Entity Listings [Line Items]  
Security 12b Title Common Stock, par value $0.15 per share
Trading Symbol OMC
Security Exchange Name NYSE
0.800% Senior Notes due 2027 [Member]  
Entity Listings [Line Items]  
Security 12b Title 0.800% Senior Notes due 2027
Trading Symbol OMC/27
Security Exchange Name NYSE
1.400% Senior Notes due 2031 [Member]  
Entity Listings [Line Items]  
Security 12b Title 1.400% Senior Notes due 2031
Trading Symbol OMC/31
Security Exchange Name NYSE
3.700% Senior Notes due 2032 [Member]  
Entity Listings [Line Items]  
Security 12b Title 3.700% Senior Notes due 2032
Trading Symbol OMC/32
Security Exchange Name NYSE
2.250% Senior Notes due 2033 [Member]  
Entity Listings [Line Items]  
Security 12b Title 2.250% Senior Notes due 2033
Trading Symbol OMC/33
Security Exchange Name NYSE