v2.4.0.6
Document and Entity Information
3 Months Ended
Jun. 30, 2012
Jul. 20, 2012
Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Jun. 30, 2012  
Document Fiscal Year Focus 2012  
Document Fiscal Period Focus Q2  
Entity Registrant Name AMERICAN TOWER CORP /MA/  
Entity Central Index Key 0001053507  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Entity Common Stock, Shares Outstanding   395,158,017