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LONG-TERM OBLIGATIONS - Key Terms of Notes (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2024	May 29, 2024	Mar. 07, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Redemption price percentage	101.00%
Senior notes
Debt Instrument [Line Items]
Redemption price percentage	100.00%
American Tower Corporation
Debt Instrument [Line Items]
Aggregate principal amount	$ 36,520.2			$ 36,472.0
American Tower Corporation \| Senior notes \| 5.200% senior notes
Debt Instrument [Line Items]
Debt interest rate (as a percent)	5.20%		5.20%
Aggregate principal amount	$ 643.0		$ 650.0	0.0
American Tower Corporation \| Senior notes \| 5.450% senior notes
Debt Instrument [Line Items]
Debt interest rate (as a percent)	5.45%		5.45%
Aggregate principal amount	$ 640.2		$ 650.0	0.0
American Tower Corporation \| Senior notes \| 3.900% senior notes
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.90%	3.90%
Aggregate principal amount	$ 530.6	$ 540.1		0.0
American Tower Corporation \| Senior notes \| 4.100% senior notes
Debt Instrument [Line Items]
Debt interest rate (as a percent)	4.10%	4.10%
Aggregate principal amount	$ 528.3	$ 540.1		$ 0.0