v3.26.1
LONG-TERM OBLIGATIONS - Repayments of Senior Notes (Details)
€ in Millions, $ in Millions
3 Months Ended 6 Months Ended
Jun. 18, 2026
USD ($)
Jun. 18, 2026
EUR (€)
May 21, 2026
USD ($)
Apr. 14, 2026
USD ($)
Feb. 13, 2026
USD ($)
Jun. 30, 2026
USD ($)
Jun. 30, 2025
USD ($)
Jun. 30, 2026
USD ($)
Jun. 30, 2025
USD ($)
Jun. 17, 2026
USD ($)
Jun. 17, 2026
EUR (€)
Dec. 31, 2025
USD ($)
Debt Instrument [Line Items]                        
Accrued and unpaid interest           $ 330.5   $ 330.5       $ 425.2
Loss on retirement of long-term obligations           3.2 $ 0.0 3.2 $ 0.0      
American Tower Corporation                        
Debt Instrument [Line Items]                        
Debt outstanding           35,379.7   35,379.7       $ 35,409.2
American Tower Corporation | Senior notes | 4.400% senior notes                        
Debt Instrument [Line Items]                        
Stated interest rate (as a percent)         4.40%             4.40%
Aggregate principal amount repaid         $ 500.0              
Debt outstanding           0.0   0.0       $ 499.9
American Tower Corporation | Senior notes | 1.600% senior notes                        
Debt Instrument [Line Items]                        
Stated interest rate (as a percent)       1.60%               1.60%
Aggregate principal amount repaid       $ 700.0                
Debt outstanding       $ 0.0   0.0   0.0       $ 699.7
American Tower Corporation | Senior notes | 1.950% senior notes                        
Debt Instrument [Line Items]                        
Stated interest rate (as a percent)     1.95%                 1.95%
Aggregate principal amount repaid     $ 500.0                  
Debt outstanding     $ 0.0     $ 0.0   $ 0.0       $ 586.9
American Tower Corporation | Senior notes | 4.125% senior notes                        
Debt Instrument [Line Items]                        
Stated interest rate (as a percent)   4.125%       4.125%   4.125%        
Aggregate principal amount repaid | €   € 250.0                    
Debt outstanding           $ 399.2   $ 399.2       $ 703.1
Redemption price percentage 100.969% 100.969%                    
Debt instrument, repurchase amount including interest $ 290.2 € 253.3                    
Accrued and unpaid interest                   $ 1.0 € 0.9  
Loss on retirement of long-term obligations 3.2                      
Loss on retirement due to prepayment consideration $ 2.8                      
Outstanding principal balance | €   € 350.0