LONG-TERM OBLIGATIONS - Long-Term Debt Obligations (Details) € in Millions, $ in Millions	Sep. 30, 2024 USD ($)	May 29, 2024 USD ($)	May 21, 2024 USD ($)	May 21, 2024 EUR (€)	May 15, 2024 USD ($)	Mar. 07, 2024 USD ($)	Feb. 14, 2024 USD ($)	Jan. 12, 2024 USD ($)	Dec. 31, 2023 USD ($)
Debt Instrument [Line Items]
Finance lease obligations	$ 17.2								$ 20.6
Total	37,098.3								38,801.3
Less current portion of long-term obligations	(3,730.5)								(3,067.3)
Long-term obligations	33,367.8								35,734.0
American Tower Corporation
Debt Instrument [Line Items]
Long-term debt	34,772.1								36,472.0
American Tower subsidiary
Debt Instrument [Line Items]
Long-term debt	2,309.0								2,308.7
2021 Multicurrency Credit Facility | Revolving Credit Facility | American Tower Corporation
Debt Instrument [Line Items]
Long-term debt	140.0								723.4
2021 Term Loan | Unsecured debt | American Tower Corporation
Debt Instrument [Line Items]
Long-term debt	997.7								997.0
2021 Credit Facility | Revolving Credit Facility | American Tower Corporation
Debt Instrument [Line Items]
Long-term debt	1,068.0								1,603.4
2021 EUR Three Year Delayed Draw Term Loan | Unsecured debt | American Tower Corporation
Debt Instrument [Line Items]
Long-term debt	0.0		$ 895.5	€ 825					$ 910.7
0.600% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)								0.60%	0.60%
Long-term debt	0.0							$ 0.0	$ 500.0
5.00% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)							5.00%		5.00%
Long-term debt	0.0						$ 0.0		$ 1,000.1
3.375% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)					3.375%				3.375%
Long-term debt	$ 0.0				$ 0.0				$ 649.7
2.950% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	2.95%
Long-term debt	$ 649.6								648.2
2.400% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	2.40%
Long-term debt	$ 749.4								748.5
1.375% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	1.375%
Long-term debt	$ 556.0								550.0
4.000% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	4.00%
Long-term debt	$ 749.1								748.1
1.300% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	1.30%
Long-term debt	$ 499.0								498.3
4.400% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	4.40%
Long-term debt	$ 499.2								498.7
1.600% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	1.60%
Long-term debt	$ 698.2								697.4
1.950% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	1.95%
Long-term debt	$ 555.1								549.6
1.450% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	1.45%
Long-term debt	$ 597.0								595.9
3.375% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.375%
Long-term debt	$ 996.1								994.7
3.125% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.125%
Long-term debt	$ 399.2								398.9
2.750% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	2.75%
Long-term debt	$ 747.7								747.0
0.450% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	0.45%
Long-term debt	$ 832.4								824.3
0.400% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	0.40%
Long-term debt	$ 553.9								548.2
3.650% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.65%
Long-term debt	$ 646.0								644.8
4.125% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	4.125%
Long-term debt	$ 665.1								658.6
3.55% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.55%
Long-term debt	$ 747.7								747.1
3.600% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.60%
Long-term debt	$ 696.7								696.0
0.500% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	0.50%
Long-term debt	$ 830.9								822.8
1.500% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	1.50%
Long-term debt	$ 647.6								647.1
5.500% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	5.50%
Long-term debt	$ 694.7								693.6
5.250% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	5.25%
Long-term debt	$ 644.8								643.9
5.800% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	5.80%
Long-term debt	$ 744.3								743.4
5.200% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	5.20%					5.20%
Long-term debt	$ 643.4					$ 650.0			0.0
3.950% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.95%
Long-term debt	$ 594.5								593.7
0.875% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	0.875%
Long-term debt	$ 831.4								823.7
3.800% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.80%
Long-term debt	$ 1,640.0								1,638.6
2.900% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	2.90%
Long-term debt	$ 744.9								744.2
3.900% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.90%	3.90%
Long-term debt	$ 551.7	$ 540.1							0.0
2.100% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	2.10%
Long-term debt	$ 743.9								743.1
0.950% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	0.95%
Long-term debt	$ 551.4								546.0
1.875% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	1.875%
Long-term debt	$ 794.0								793.3
2.700% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	2.70%
Long-term debt	$ 695.5								695.0
4.625% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	4.625%
Long-term debt	$ 550.6								545.2
2.300% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	2.30%
Long-term debt	$ 693.4								692.7
1.000% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	1.00%
Long-term debt	$ 718.2								711.5
4.050% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	4.05%
Long-term debt	$ 643.5								642.9
5.650% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	5.65%
Long-term debt	$ 791.2								790.6
1.250% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	1.25%
Long-term debt	$ 551.0								545.8
5.550% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	5.55%
Long-term debt	$ 841.2								840.6
5.900% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	5.90%
Long-term debt	$ 742.0								741.5
5.450% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	5.45%					5.45%
Long-term debt	$ 640.4					$ 650.0			0.0
4.100% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	4.10%	4.10%
Long-term debt	$ 549.5	$ 540.1							0.0
3.700% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.70%
Long-term debt	$ 592.6								592.4
3.100% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.10%
Long-term debt	$ 1,038.8								1,038.6
2.950% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	2.95%
Long-term debt	$ 1,023.6								1,023.2
Series 2015-2 notes | Secured debt | American Tower subsidiary
Debt Instrument [Line Items]
Long-term debt	524.6								524.1
Series 2018-1A securities | Secured debt | American Tower subsidiary
Debt Instrument [Line Items]
Long-term debt	497.4								496.8
Series 2023-1A Securities | Secured debt | American Tower subsidiary
Debt Instrument [Line Items]
Long-term debt	1,287.0								1,284.4
Other subsidiary debt | Unsecured debt | American Tower subsidiary
Debt Instrument [Line Items]
Long-term debt	$ 0.0								$ 3.4