BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Property and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Labor costs capitalized		$ 64.4	$ 65.2	$ 59.4
Depreciation, amortization and accretion		(3,086.5)	(3,355.1)	$ (2,332.6)
Right-of-use asset		$ 8,878.8	$ 8,918.9
Tower
Property, Plant and Equipment [Line Items]
Estimated useful life of respective assets		20 years
Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life of respective assets		20 years
Maximum | Service Life | Scenario, Forecast
Property, Plant and Equipment [Line Items]
Depreciation, amortization and accretion	$ 800.0
Right-of-use asset	550.0
Minimum
Property, Plant and Equipment [Line Items]
Operating history, period		20 years
Minimum | Service Life | Scenario, Forecast
Property, Plant and Equipment [Line Items]
Depreciation, amortization and accretion	700.0
Right-of-use asset	$ 450.0