OTHER ASSETS - Equity Investments and Other Investments (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		1 Months Ended	3 Months Ended		6 Months Ended
	Nov. 18, 2020	Apr. 30, 2021	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Schedule of Equity Method Investments [Line Items]
Income (loss) from equity method investments			$ 2.0	$ (7.0)	$ 11.0	$ (13.0)
Investments in equity securities			550.0		550.0		$ 400.0
Fair value adjustment			(67.0)	(0.1)	56.0	(2.0)
Equity investments, net of cumulative impairment			22.0		22.0		26.0
Cumulative impairment			7.0		7.0		$ 7.0
Impairment recorded			0.0	0.0	0.0	0.0
Incremental investment					164.0	48.0
YES Network
Schedule of Equity Method Investments [Line Items]
Income (loss) from equity method investments			$ 6.0	$ 2.0	$ 19.0	$ 7.0
Bally's
Schedule of Equity Method Investments [Line Items]
Penny warrants acquirable (up to) (in shares)	8.2
Number of penny warrants exercisable (in shares)	3.3
Options available to purchase (up to) (in shares)	1.6
Option purchase price, minimum (in USD per share)	$ 30
Option purchase price, maximum (in USD per share)	$ 45
Vesting period	4 years
Incremental investment		$ 93.0
Number of warrants convertible (in shares)		1.7
Exercise price (in USD per share)		$ 0.01