LONG-TERM OBLIGATIONS - Schedule of Long-Term Debt Obligations (Details) € in Millions, $ in Millions	Sep. 30, 2023 USD ($)	Sep. 30, 2023 EUR (€)	Sep. 15, 2023 USD ($)	Jun. 27, 2023 USD ($)	May 25, 2023 USD ($)	May 16, 2023 USD ($)	Mar. 03, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 08, 2021 USD ($)
Debt Instrument [Line Items]
Finance lease obligations	$ 21.1							$ 27.8
Total	38,599.9							38,670.2
Less current portion of long-term obligations	(3,157.5)							(4,514.2)
Long-term obligations	35,442.4							34,156.0
American Tower Corporation
Debt Instrument [Line Items]
Long-term debt	36,142.6							36,307.0
American Tower subsidiary
Debt Instrument [Line Items]
Long-term debt	2,436.2							2,335.4
2021 Multicurrency Credit Facility | Line of credit | Revolving Credit Facility | American Tower Corporation
Debt Instrument [Line Items]
Long-term debt	261.0							3,788.7
2021 Term Loan | Unsecured debt | American Tower Corporation
Debt Instrument [Line Items]
Long-term debt	996.8							996.3	$ 1,000.0
2021 Credit Facility | Line of credit | Revolving Credit Facility | American Tower Corporation
Debt Instrument [Line Items]
Long-term debt	2,088.4							1,080.0
2021 EUR Three Year Delayed Draw Term Loan | Unsecured debt | American Tower Corporation
Debt Instrument [Line Items]
Long-term debt	872.2	€ 825.0						882.9
2021 USD Two Year Delayed Draw Term Loan | Unsecured debt | American Tower Corporation
Debt Instrument [Line Items]
Long-term debt	$ 0.0			$ 1,500.0				1,499.3
3.50% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.50%	3.50%
Long-term debt	$ 0.0							999.8
3.000% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.00%	3.00%
Long-term debt	$ 0.0							694.5
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	$ 499.7							498.9
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	$ 1,000.2							1,000.5
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	$ 649.4							648.3
2.950% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	2.95%	2.95%
Long-term debt	$ 647.7							646.4
2.400% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	2.40%	2.40%
Long-term debt	$ 748.2							747.3
1.375% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	1.375%	1.375%
Long-term debt	$ 526.5							532.1
4.000% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	4.00%	4.00%
Long-term debt	$ 747.7							746.8
1.300% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	1.30%	1.30%
Long-term debt	$ 498.1							497.3
4.400% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	4.40%	4.40%
Long-term debt	$ 498.6							498.1
1.600% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	1.60%	1.60%
Long-term debt	$ 697.1							696.3
1.950% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	1.95%	1.95%
Long-term debt	$ 526.2							532.1
1.450% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	1.45%	1.45%
Long-term debt	$ 595.5							594.5
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	$ 994.2							992.9
3.125% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.125%	3.125%
Long-term debt	$ 398.8							398.6
2.750% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	2.75%	2.75%
Long-term debt	$ 746.8							746.1
0.450% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	0.45%	0.45%
Long-term debt	$ 789.1							798.2
0.400% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	0.40%	0.40%
Long-term debt	$ 524.6							530.4
3.650% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.65%	3.65%
Long-term debt	$ 644.4							643.3
4.125% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	4.125%	4.125%				4.125%
Long-term debt	$ 630.4					$ 652.1		0.0
3.55% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.55%	3.55%
Long-term debt	$ 746.9							746.3
3.600% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.60%	3.60%
Long-term debt	$ 695.8							695.1
0.500% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	0.50%	0.50%
Long-term debt	$ 787.5							796.6
1.500% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	1.50%	1.50%
Long-term debt	$ 647.0							646.5
5.500% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	5.50%	5.50%					5.50%
Long-term debt	$ 693.3						$ 700.0	0.0
5.250% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	5.25%	5.25%			5.25%
Long-term debt	$ 643.6				$ 650.0			0.0
5.800% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	5.80%	5.80%	5.80%
Long-term debt	$ 743.1		$ 750.0					0.0
3.950% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.95%	3.95%
Long-term debt	$ 593.4							592.6
0.875% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	0.875%	0.875%
Long-term debt	$ 788.6							797.8
3.800% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.80%	3.80%
Long-term debt	$ 1,638.2							1,636.8
2.900% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	2.90%	2.90%
Long-term debt	$ 744.0							743.4
2.100% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	2.10%	2.10%
Long-term debt	$ 742.9							742.2
0.950% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	0.95%	0.95%
Long-term debt	$ 522.5							528.5
1.875% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	1.875%	1.875%
Long-term debt	$ 793.1							792.5
2.700% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	2.70%	2.70%
Long-term debt	$ 694.9							694.4
4.625% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	4.625%	4.625%				4.625%
Long-term debt	$ 521.7					$ 543.4		0.0
2.300% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	2.30%	2.30%
Long-term debt	$ 692.5							691.9
1.000% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	1.00%	1.00%
Long-term debt	$ 681.0							689.1
4.050% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	4.05%	4.05%
Long-term debt	$ 642.7							642.2
5.650% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	5.65%	5.65%					5.65%
Long-term debt	$ 790.3						$ 800.0	0.0
1.250% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	1.25%	1.25%
Long-term debt	$ 522.3							528.5
5.550% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	5.55%	5.55%			5.55%
Long-term debt	$ 840.5				$ 850.0			0.0
5.900% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	5.90%	5.90%	5.90%
Long-term debt	$ 741.3		$ 750.0					0.0
3.700% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.70%	3.70%
Long-term debt	$ 592.4							592.2
3.100% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	3.10%	3.10%
Long-term debt	$ 1,038.5							1,038.3
2.950% senior notes | Senior notes | American Tower Corporation
Debt Instrument [Line Items]
Debt interest rate (as a percent)	2.95%	2.95%
Long-term debt	$ 1,023.0							1,022.5
Series 2013-2A securities | Secured debt | American Tower subsidiary
Debt Instrument [Line Items]
Long-term debt	0.0							1,299.7
Series 2018-1A securities | Secured debt | American Tower subsidiary
Debt Instrument [Line Items]
Long-term debt	496.6							496.1
Series 2023-1A Securities | Secured debt | American Tower subsidiary
Debt Instrument [Line Items]
Long-term debt	1,283.4							0.0
Series 2015-2 notes | Secured debt | American Tower subsidiary
Debt Instrument [Line Items]
Long-term debt	523.9							523.4
Other subsidiary debt | Unsecured debt | American Tower subsidiary
Debt Instrument [Line Items]
Long-term debt	$ 132.3							$ 16.2