Intangible Assets and Goodwill - Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2019
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross amount		$ 809.9		$ 798.6
Intangible assets subject to amortization, accumulated amortization		(466.2)		(392.5)
Intangible assets subject to amortization, net amount		343.7		406.1
Indefinite-lived Intangible Assets [Line Items]
Intangible assets not subject to amortization		1,410.4		1,407.5
Intangible assets, net		1,754.1		1,813.6
Amortization expense		77.7	$ 77.6
Future amortization expense for intangible assets [Abstract]
Future amortization expense, fiscal 2020		143.3
Future amortization expense, fiscal 2021		91.8
Future amortization expense, fiscal 2022		44.2
Future amortization expense, fiscal 2023		41.5
Future amortization expense, fiscal 2024		34.0
Trademarks | National media
Indefinite-lived Intangible Assets [Line Items]
Intangible assets not subject to amortization		726.9		724.5
Future amortization expense for intangible assets [Abstract]
Impairment of intangible assets, indefinite-lived (excluding goodwill)	$ 5.2
Internet domain names | National media
Indefinite-lived Intangible Assets [Line Items]
Intangible assets not subject to amortization		8.3		7.8
FCC licenses | Local media
Indefinite-lived Intangible Assets [Line Items]
Intangible assets not subject to amortization		675.2		675.2
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		(158.3)		(155.1)
Intangible assets subject to amortization, net amount		71.0		74.2
Advertiser relationships | National media
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross amount		211.0		213.3
Intangible assets subject to amortization, accumulated amortization		(134.9)		(102.0)
Intangible assets subject to amortization, net amount		76.1		111.3
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		(8.0)		(5.8)
Intangible assets subject to amortization, net amount		4.5		6.7
Publisher relationships | National media
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross amount		132.8		125.0
Intangible assets subject to amortization, accumulated amortization		(34.5)		(25.4)
Intangible assets subject to amortization, net amount		98.3		99.6
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		(30.6)		(22.7)
Intangible assets subject to amortization, net amount		67.6		75.5
Customer relationships | National media
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross amount		70.4		67.5
Intangible assets subject to amortization, accumulated amortization		(62.1)		(46.3)
Intangible assets subject to amortization, net amount		8.3		21.2
Retransmission agreements | Local media
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross amount		27.9		27.9
Intangible assets subject to amortization, accumulated amortization		(21.2)		(19.1)
Intangible assets subject to amortization, net amount		6.7		8.8
Other | National media
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross amount		26.1		23.2
Intangible assets subject to amortization, accumulated amortization		(15.2)		(14.9)
Intangible assets subject to amortization, net amount		10.9		8.3
Other | Local media
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross amount		1.7		1.7
Intangible assets subject to amortization, accumulated amortization		(1.4)		(1.2)
Intangible assets subject to amortization, net amount		$ 0.3		$ 0.5