v3.19.2
Cover Cover
Jul. 31, 2019
Entity Information [Line Items]  
Document Type 8-K
Document Period End Date Jul. 31, 2019
Entity Registrant Name AMERICAN TOWER CORP /MA/
Entity Central Index Key 0001053507
Amendment Flag false
Entity Incorporation, State or Country Code DE
Entity File Number 001-14195
Entity Tax Identification Number 65-0723837
Entity Address, Address Line One 116 Huntington Avenue
Entity Address, City or Town Boston
Entity Address, State or Province MA
Entity Address, Postal Zip Code 02116
City Area Code 617
Local Phone Number 375-7500
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Entity Emerging Growth Company false
NEW YORK STOCK EXCHANGE, INC. | Common Stock  
Entity Information [Line Items]  
Title of 12(b) Security Common Stock, $0.01 par value
Trading Symbol  AMT
Security Exchange Name NYSE
NEW YORK STOCK EXCHANGE, INC. | 1.375% Senior Notes due 2025  
Entity Information [Line Items]  
Title of 12(b) Security 1.375% Senior Notes due 2025
Trading Symbol AMT 25A
Security Exchange Name NYSE
NEW YORK STOCK EXCHANGE, INC. | 1.950% Senior Notes due 2026  
Entity Information [Line Items]  
Title of 12(b) Security 1.950% Senior Notes due 2026
Trading Symbol AMT 26B
Security Exchange Name NYSE