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LONG-TERM OBLIGATIONS - Offerings of Senior Notes (Details) - USD ($) $ in Millions		3 Months Ended
	Mar. 07, 2024	Mar. 31, 2024	Mar. 31, 2023
Debt Instrument [Line Items]
Proceeds from issuance of senior long-term debt		$ 1,293.0	$ 1,494.2
Redemption price percentage		101.00%
Senior Notes
Debt Instrument [Line Items]
Redemption price percentage		100.00%
American Tower Corporation \| Senior Notes \| 5.200% senior notes
Debt Instrument [Line Items]
Debt interest rate (as a percent)	5.20%	5.20%
Debt face amount	$ 650.0
American Tower Corporation \| Senior Notes \| 5.450% senior notes
Debt Instrument [Line Items]
Debt interest rate (as a percent)	5.45%	5.45%
Debt face amount	$ 650.0
American Tower Corporation \| Senior Notes \| 5.200% Senior Notes Due 2029 And 5.450% Senior Notes Due 2034
Debt Instrument [Line Items]
Proceeds from issuance of senior long-term debt	$ 1,281.3