LONG-TERM OBLIGATIONS - Credit Facilities and Term Loans (Details) - American Tower Corporation $ in Millions	6 Months Ended
Jun. 30, 2024 USD ($) renewalPeriod	Dec. 31, 2023 USD ($)
Line of Credit Facility [Line Items]
Long-term debt	$ 36,520.2	$ 36,472.0
Revolving Credit Facility
Line of Credit Facility [Line Items]
Number of optional renewal periods \| renewalPeriod	2
2021 Multicurrency Credit Facility \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Long-term debt	$ 1,170.0	723.4
Outstanding principal balance	1,170.0
Undrawn letters of credit	$ 3.5
Current margin over LIBOR or EURIBOR	1.125%
Current commitment fee, percentage	0.11%
2021 Credit Facility \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Long-term debt	$ 2,113.4	1,603.4
Outstanding principal balance	2,113.4
Undrawn letters of credit	$ 30.4
Current margin over LIBOR or EURIBOR	1.125%
Current commitment fee, percentage	0.11%
2021 Term Loan \| Unsecured debt
Line of Credit Facility [Line Items]
Long-term debt	$ 997.4	$ 997.0
Outstanding principal balance	$ 1,000.0
Current margin over LIBOR or EURIBOR	1.125%

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