v3.10.0.1
Document and Entity Information - shares
6 Months Ended
Jun. 30, 2018
Jul. 16, 2018
Document and Entity Information    
Amendment Flag false  
Entity Registrant Name INTERPUBLIC GROUP OF COMPANIES, INC.  
Entity Central Index Key 0000051644  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Document Type 10-Q  
Document Period End Date Jun. 30, 2018  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q2  
Entity Common Stock, Shares Outstanding   383,785,420