Segment Information - Adjusted OIBDA by Segment and Reconciliation to Consolidated Net Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Net income (loss) before allocation to non-controlling interests	$ (58.0)	$ 50.3	$ (51.7)	$ 56.4
Provision for income taxes	(1.5)	6.2	(3.2)	5.2
Equity in earnings of investee companies, net of tax	0.3	(1.7)	(0.1)	(2.5)
Interest expense, net	33.3	33.9	63.1	66.6
Other loss, net	0.0	0.0	(0.2)	(0.1)
Operating income (loss)	(25.9)	88.7	7.9	125.6
Restructuring charges	4.7	0.0	4.7	0.3
Net (gain) loss on dispositions	(5.2)	0.4	(5.3)	(1.1)
Depreciation and amortization	42.9	49.0	90.2	94.8
Stock-based compensation	5.2	5.5	11.0	10.8
Adjusted OIBDA	21.7	143.6	108.5	230.4
Capital expenditures			31.9	39.6
Operating segments
Segment Reporting Information [Line Items]
Operating income (loss)	(25.9)	88.7	7.9	125.6
Net (gain) loss on dispositions	(5.2)	0.4	(5.3)	(1.1)
Depreciation and amortization	42.9	49.0	90.2	94.8
Capital expenditures	13.7	21.5	31.9	39.6
Operating segments | U.S. Media
Segment Reporting Information [Line Items]
Operating income (loss)	(3.9)	101.9	43.5	157.4
Restructuring charges	3.0		3.0
Net (gain) loss on dispositions	(1.1)	0.2	(1.2)	(1.3)
Depreciation and amortization	39.4	43.7	82.9	84.3
Adjusted OIBDA	37.4	145.8	128.2	240.4
Capital expenditures	13.6	21.0	30.9	38.3
Operating segments | Other
Segment Reporting Information [Line Items]
Operating income (loss)	(5.5)	3.3	(8.8)	(0.7)
Restructuring charges	0.7		0.7
Net (gain) loss on dispositions	(4.1)	0.2	(4.1)	0.2
Depreciation and amortization	3.5	5.3	7.3	10.5
Adjusted OIBDA	(5.4)	8.8	(4.9)	10.0
Capital expenditures	0.1	0.5	1.0	1.3
Corporate
Segment Reporting Information [Line Items]
Operating income (loss)	(16.5)	(16.5)	(26.8)	(31.1)
Restructuring charges			1.0	0.3
Adjusted OIBDA	$ (10.3)	$ (11.0)	$ (14.8)	$ (20.0)