CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 577.3	$ 819.7	$ 1,353.8	$ 2,413.3
Other comprehensive income (loss):
Foreign currency translation adjustments, net of tax (benefit) expense of $(0.2), $(0.8), $0.0 and $(1.0), respectively	(624.6)	(1,075.9)	(406.1)	(2,117.9)
Other comprehensive loss	(624.6)	(1,075.9)	(406.1)	(2,117.9)
Comprehensive (loss) income	(47.3)	(256.2)	947.7	295.4
Comprehensive loss attributable to noncontrolling interests	128.9	225.9	103.1	494.9
Comprehensive income (loss) attributable to American Tower Corporation stockholders	$ 81.6	$ (30.3)	$ 1,050.8	$ 790.3