LONG-TERM OBLIGATIONS - Key Terms Related to Outstanding Senior Notes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Sep. 27, 2021	Nov. 20, 2020	Sep. 28, 2020	Jun. 03, 2020	Jan. 10, 2014	Aug. 19, 2013
Debt Instrument [Line Items]
Adjustments to principal amount	$ (231.6)
Redemption price percentage	101.00%
Senior Notes
Debt Instrument [Line Items]
Redemption price percentage	100.00%
Senior Notes | 3.000% Notes
Debt Instrument [Line Items]
Debt interest rate	3.00%
Senior Notes | 3.000% Notes | Interest Rate Swap
Debt Instrument [Line Items]
Fair value adjustment due to interest rate swaps	$ (4.9)	$ 11.8
Senior Notes | 5.00% Notes
Debt Instrument [Line Items]
Debt interest rate								5.00%
Senior Notes | American Tower Corporation | 3.50% Notes
Debt Instrument [Line Items]
Debt interest rate	3.50%
Aggregate Principal Amount	$ 1,000.0
Adjustments to principal amount	$ (0.2)	(2.1)
Senior Notes | American Tower Corporation | 3.000% Notes
Debt Instrument [Line Items]
Debt interest rate	3.00%
Aggregate Principal Amount	$ 700.0
Adjustments to principal amount	$ (5.5)	9.9
Senior Notes | American Tower Corporation | 0.600% Notes
Debt Instrument [Line Items]
Debt interest rate	0.60%
Aggregate Principal Amount	$ 500.0
Adjustments to principal amount	$ (1.1)	(2.1)
Senior Notes | American Tower Corporation | 5.00% Notes
Debt Instrument [Line Items]
Debt interest rate	5.00%						5.00%
Aggregate Principal Amount	$ 1,000.0
Adjustments to principal amount	$ 0.5	0.9
Senior Notes | American Tower Corporation | 3.375% Notes
Debt Instrument [Line Items]
Debt interest rate	3.375%
Aggregate Principal Amount	$ 650.0
Adjustments to principal amount	$ (1.7)	(3.0)
Senior Notes | American Tower Corporation | 2.950% Notes
Debt Instrument [Line Items]
Debt interest rate	2.95%
Aggregate Principal Amount	$ 650.0
Adjustments to principal amount	$ (3.6)	(5.3)
Senior Notes | American Tower Corporation | 2.400% Notes
Debt Instrument [Line Items]
Debt interest rate	2.40%
Aggregate Principal Amount	$ 750.0
Adjustments to principal amount	$ (2.7)	(3.9)
Senior Notes | American Tower Corporation | 1.375% Notes
Debt Instrument [Line Items]
Debt interest rate	1.375%
Aggregate Principal Amount	$ 535.3
Adjustments to principal amount	$ (3.2)	(4.8)
Senior Notes | American Tower Corporation | 4.000% Notes
Debt Instrument [Line Items]
Debt interest rate	4.00%
Aggregate Principal Amount	$ 750.0
Adjustments to principal amount	$ (3.2)	(4.5)
Senior Notes | American Tower Corporation | 1.300% Notes
Debt Instrument [Line Items]
Debt interest rate	1.30%
Aggregate Principal Amount	$ 500.0
Adjustments to principal amount	$ (2.7)	(3.6)
Senior Notes | American Tower Corporation | 4.400% Notes
Debt Instrument [Line Items]
Debt interest rate	4.40%
Aggregate Principal Amount	$ 500.0
Adjustments to principal amount	$ (1.9)	(2.4)
Senior Notes | American Tower Corporation | 1.600% Notes
Debt Instrument [Line Items]
Debt interest rate	1.60%
Aggregate Principal Amount	$ 700.0
Adjustments to principal amount	$ (3.7)	(4.8)
Senior Notes | American Tower Corporation | 1.950% Notes
Debt Instrument [Line Items]
Debt interest rate	1.95%
Aggregate Principal Amount	$ 535.3
Adjustments to principal amount	$ (3.2)	(4.3)
Senior Notes | American Tower Corporation | 1.450% Notes
Debt Instrument [Line Items]
Debt interest rate	1.45%
Aggregate Principal Amount	$ 600.0
Adjustments to principal amount	$ (5.5)	(7.0)
Senior Notes | American Tower Corporation | 3.375% Notes
Debt Instrument [Line Items]
Debt interest rate	3.375%
Aggregate Principal Amount	$ 1,000.0
Adjustments to principal amount	$ (7.1)	(8.8)
Senior Notes | American Tower Corporation | 3.125% Notes
Debt Instrument [Line Items]
Debt interest rate	3.125%
Aggregate Principal Amount	$ 400.0
Adjustments to principal amount	$ (1.4)	(1.7)
Senior Notes | American Tower Corporation | 2.750% Notes
Debt Instrument [Line Items]
Debt interest rate	2.75%
Aggregate Principal Amount	$ 750.0
Adjustments to principal amount	$ (3.9)	(4.8)
Senior Notes | American Tower Corporation | 0.450% Notes
Debt Instrument [Line Items]
Debt interest rate	0.45%
Aggregate Principal Amount	$ 802.9
Adjustments to principal amount	$ (4.7)	(5.9)
Senior Notes | American Tower Corporation | 0.400% Notes
Debt Instrument [Line Items]
Debt interest rate	0.40%
Aggregate Principal Amount	$ 535.3
Adjustments to principal amount	$ (4.9)	(6.1)
Senior Notes | American Tower Corporation | 3.650% Notes
Debt Instrument [Line Items]
Debt interest rate	3.65%
Aggregate Principal Amount	$ 650.0
Adjustments to principal amount	$ (6.7)	0.0
Senior Notes | American Tower Corporation | 3.55% Notes
Debt Instrument [Line Items]
Debt interest rate	3.55%
Aggregate Principal Amount	$ 750.0
Adjustments to principal amount	$ (3.7)	(4.5)
Senior Notes | American Tower Corporation | 3.600% Notes
Debt Instrument [Line Items]
Debt interest rate	3.60%
Aggregate Principal Amount	$ 700.0
Adjustments to principal amount	$ (4.9)	(5.7)
Senior Notes | American Tower Corporation | 0.500% Notes
Debt Instrument [Line Items]
Debt interest rate	0.50%
Aggregate Principal Amount	$ 802.9
Adjustments to principal amount	$ (6.3)	(7.7)
Senior Notes | American Tower Corporation | 1.500% Notes
Debt Instrument [Line Items]
Debt interest rate	1.50%
Aggregate Principal Amount	$ 650.0
Adjustments to principal amount	$ (3.5)	(4.2)
Senior Notes | American Tower Corporation | 3.950% Notes
Debt Instrument [Line Items]
Debt interest rate	3.95%
Aggregate Principal Amount	$ 600.0
Adjustments to principal amount	$ (7.4)	(8.4)
Senior Notes | American Tower Corporation | 0.875% Notes
Debt Instrument [Line Items]
Debt interest rate	0.875%
Aggregate Principal Amount	$ 802.9
Adjustments to principal amount	$ (5.1)	(5.7)
Senior Notes | American Tower Corporation | 3.800% Notes
Debt Instrument [Line Items]
Debt interest rate	3.80%
Aggregate Principal Amount	$ 1,650.0
Adjustments to principal amount	$ (13.2)	(14.9)
Senior Notes | American Tower Corporation | 2.900% Notes
Debt Instrument [Line Items]
Debt interest rate	2.90%
Aggregate Principal Amount	$ 750.0
Adjustments to principal amount	$ (6.6)	(7.5)
Senior Notes | American Tower Corporation | 2.100% Notes
Debt Instrument [Line Items]
Debt interest rate	2.10%
Aggregate Principal Amount	$ 750.0
Adjustments to principal amount	$ (7.8)	(8.8)
Senior Notes | American Tower Corporation | 0.950% Notes
Debt Instrument [Line Items]
Debt interest rate	0.95%
Aggregate Principal Amount	$ 535.3
Adjustments to principal amount	$ (6.8)	(7.6)
Senior Notes | American Tower Corporation | 1.875% Notes
Debt Instrument [Line Items]
Debt interest rate	1.875%
Aggregate Principal Amount	$ 800.0
Adjustments to principal amount	$ (7.5)	(8.6)
Senior Notes | American Tower Corporation | 2.700% Notes
Debt Instrument [Line Items]
Debt interest rate	2.70%
Aggregate Principal Amount	$ 700.0
Adjustments to principal amount	$ (5.6)	(6.3)
Senior Notes | American Tower Corporation | 2.300% Notes
Debt Instrument [Line Items]
Debt interest rate	2.30%
Aggregate Principal Amount	$ 700.0
Adjustments to principal amount	$ (8.1)	(9.0)
Senior Notes | American Tower Corporation | 1.000% Notes
Debt Instrument [Line Items]
Debt interest rate	1.00%
Aggregate Principal Amount	$ 695.9
Adjustments to principal amount	$ (6.8)	(7.5)
Senior Notes | American Tower Corporation | 4.050% Notes
Debt Instrument [Line Items]
Debt interest rate	4.05%
Aggregate Principal Amount	$ 650.0
Adjustments to principal amount	$ (7.8)	0.0
Senior Notes | American Tower Corporation | 1.250% Notes
Debt Instrument [Line Items]
Debt interest rate	1.25%
Aggregate Principal Amount	$ 535.3
Adjustments to principal amount	$ (6.8)	(7.4)
Senior Notes | American Tower Corporation | 3.700% Notes
Debt Instrument [Line Items]
Debt interest rate	3.70%
Aggregate Principal Amount	$ 600.0
Adjustments to principal amount	$ (7.8)	(7.9)
Senior Notes | American Tower Corporation | 3.100% Notes
Debt Instrument [Line Items]
Debt interest rate	3.10%				3.10%	3.10%
Aggregate Principal Amount	$ 1,050.0
Adjustments to principal amount	$ (11.7)	(12.0)
Senior Notes | American Tower Corporation | 2.950% Notes
Debt Instrument [Line Items]
Debt interest rate	2.95%		2.95%	2.95%
Aggregate Principal Amount	$ 1,050.0
Adjustments to principal amount	$ (27.5)	$ (28.5)