CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
REVENUES:
Revenue from contracts with customers	$ 527.2	$ 491.3
Revenues	7,580.3	7,440.1	$ 6,663.9
OPERATING EXPENSES:
Property	2,173.7	2,128.7	2,022.0
Services	43.1	49.1	34.6
Depreciation, amortization and accretion	1,778.4	2,110.8	1,715.9
Selling, general, administrative and development expense	730.4	733.2	637.0
Other operating expenses	166.3	513.3	256.0
Total operating expenses	4,891.9	5,535.1	4,665.5
OPERATING INCOME	2,688.4	1,905.0	1,998.4
OTHER INCOME (EXPENSE):
Interest (expense) income, TV Azteca	0.0	(0.1)	10.8
Interest income	46.8	54.7	35.4
Interest expense	(814.2)	(825.5)	(749.6)
Loss on retirement of long-term obligations	(22.2)	(3.3)	(70.2)
Other income (including foreign currency gains (losses) of $6.1, ($4.5), and $26.4, respectively)	17.6	23.8	31.3
Total other expense	(772.0)	(750.4)	(742.3)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	1,916.4	1,154.6	1,256.1
Income tax benefit (provision)	0.2	110.1	(30.7)
NET INCOME	1,916.6	1,264.7	1,225.4
Net (income) loss attributable to noncontrolling interests	(28.8)	(28.3)	13.5
NET INCOME ATTRIBUTABLE TO AMERICAN TOWER CORPORATION STOCKHOLDERS	1,887.8	1,236.4	1,238.9
Dividends on preferred stock	0.0	(9.4)	(87.4)
NET INCOME ATTRIBUTABLE TO AMERICAN TOWER CORPORATION COMMON STOCKHOLDERS	$ 1,887.8	$ 1,227.0	$ 1,151.5
NET INCOME PER COMMON SHARE AMOUNTS:
Basic net income attributable to American Tower Corporation common stockholders (in dollars per share)	$ 4.27	$ 2.79	$ 2.69
Diluted net income attributable to American Tower Corporation common stockholders (in dollars per share)	$ 4.24	$ 2.77	$ 2.67
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING:
BASIC (in shares)	442,319	439,606	428,181
DILUTED (in shares)	445,520	442,960	431,688
Property
REVENUES:
Revenues	$ 7,464.9	$ 7,314.7	$ 6,565.9
Services
REVENUES:
Revenue from contracts with customers	$ 115.4	$ 125.4	$ 98.0