LONG-TERM OBLIGATIONS - Repayments of Senior Notes (Details) - American Tower Corporation € in Millions, $ in Millions	May 30, 2025 USD ($)	Apr. 03, 2025 EUR (€)	Mar. 14, 2025 USD ($)	Jan. 14, 2025 USD ($)	Jun. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)
Debt Instrument [Line Items]
Debt outstanding					$ 35,673.9	$ 34,174.9
2.950% senior notes \| Senior notes
Debt Instrument [Line Items]
Debt interest rate (as a percent)				2.95%		2.95%
Aggregate principal amount repaid				$ 650.0
Debt outstanding					0.0	$ 650.0
2.400% senior notes \| Senior notes
Debt Instrument [Line Items]
Debt interest rate (as a percent)			2.40%			2.40%
Aggregate principal amount repaid			$ 750.0
Debt outstanding					$ 0.0	$ 749.7
4.900% senior notes \| Senior notes
Debt Instrument [Line Items]
Debt interest rate (as a percent)			4.90%		4.90%
Debt outstanding					$ 644.2	0.0
5.350% senior notes \| Senior notes
Debt Instrument [Line Items]
Debt interest rate (as a percent)			5.35%		5.35%
Debt outstanding					$ 346.2	$ 0.0
1.375% senior notes \| Senior notes
Debt Instrument [Line Items]
Debt interest rate (as a percent)		1.375%				1.375%
Aggregate principal amount repaid \| €		€ 500.0
Debt outstanding					0.0	$ 517.3
4.000% senior notes \| Senior notes
Debt Instrument [Line Items]
Debt interest rate (as a percent)	4.00%					4.00%
Aggregate principal amount repaid	$ 750.0
Debt outstanding					$ 0.0	$ 749.4