Intangible Assets and Goodwill - Intangible Assets subject to Amortization (Details) - USD ($) $ in Millions	Sep. 30, 2020	Jun. 30, 2020
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross amount	$ 727.0	$ 811.0
Intangible assets subject to amortization, accumulated amortization	(478.0)	(531.4)
Intangible assets subject to amortization, net amount	249.0	279.6
Indefinite-lived Intangible Assets [Line Items]
Intangible assets not subject to amortization, gross amount	1,367.9	1,367.9
Intangible assets, net	1,616.9	1,647.5
Trademarks | National Media
Indefinite-lived Intangible Assets [Line Items]
Intangible assets not subject to amortization, gross amount	706.7	706.7
Internet domain names | National Media
Indefinite-lived Intangible Assets [Line Items]
Intangible assets not subject to amortization, gross amount	8.3	8.3
FCC licenses | Local Media
Indefinite-lived Intangible Assets [Line Items]
Intangible assets not subject to amortization, gross amount	652.9	652.9
Network affiliation agreements | Local Media
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross amount	229.3	229.3
Intangible assets subject to amortization, accumulated amortization	(163.1)	(161.5)
Intangible assets subject to amortization, net amount	66.2	67.8
Advertiser relationships | National Media
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross amount	211.0	211.0
Intangible assets subject to amortization, accumulated amortization	(187.6)	(170.0)
Intangible assets subject to amortization, net amount	23.4	41.0
Advertiser relationships | Local Media
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross amount	12.5	12.5
Intangible assets subject to amortization, accumulated amortization	(11.1)	(10.1)
Intangible assets subject to amortization, net amount	1.4	2.4
Publisher relationships | National Media
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross amount	132.8	132.8
Intangible assets subject to amortization, accumulated amortization	(48.6)	(43.9)
Intangible assets subject to amortization, net amount	84.2	88.9
Partner relationships | National Media
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross amount	98.2	98.2
Intangible assets subject to amortization, accumulated amortization	(42.7)	(38.7)
Intangible assets subject to amortization, net amount	55.5	59.5
Customer relationships | National Media
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross amount	8.0	71.3
Intangible assets subject to amortization, accumulated amortization	(2.7)	(65.6)
Intangible assets subject to amortization, net amount	5.3	5.7
Retransmission agreements | Local Media
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross amount	10.6	27.9
Intangible assets subject to amortization, accumulated amortization	(6.2)	(23.1)
Intangible assets subject to amortization, net amount	4.4	4.8
Other | National Media
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross amount	23.9	26.3
Intangible assets subject to amortization, accumulated amortization	(15.4)	(16.9)
Intangible assets subject to amortization, net amount	8.5	9.4
Other | Local Media
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross amount	0.7	1.7
Intangible assets subject to amortization, accumulated amortization	(0.6)	(1.6)
Intangible assets subject to amortization, net amount	$ 0.1	$ 0.1