Goodwill and Intangible Assets - Schedule of Intangible Assets (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Finite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross carrying amount	$ 963.0	$ 193.2
Accumulated amortization	(8.4)	(51.5)
Intangible assets subject to amortization, net amount	954.6	141.7
Fair Value	969.6	199.6
Intangible assets, net amount	961.2	148.1
FCC Licenses and Spectrum Usage Rights [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets not subject to amortization	6.6	6.4
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross carrying amount	850.0	141.6
Accumulated amortization	(7.1)	(38.9)
Intangible assets subject to amortization, net amount	842.9	102.7
Trade Names [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross carrying amount	108.0	41.7
Accumulated amortization	(1.2)	(9.4)
Intangible assets subject to amortization, net amount	106.8	32.3
Technology [Member]
Finite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross carrying amount	5.0	9.9
Accumulated amortization	(0.1)	(3.2)
Intangible assets subject to amortization, net amount	$ 4.9	$ 6.7