UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 27, 2020	Dec. 29, 2019	Dec. 27, 2020	Dec. 29, 2019
Statement of Comprehensive Income [Abstract]
Net loss	$ (82.7)	$ (54.0)	$ (266.8)	$ (91.8)
Other comprehensive loss:
Net unrealized (loss) gain on available-for-sale securities	(0.5)	(0.3)	(0.5)	0.2
Comprehensive loss	(83.2)	(54.3)	(267.3)	(91.6)
Net income from discontinued operations attributable to noncontrolling interest	0.3	0.3	0.6	0.3
Comprehensive loss attributable to controlling interest	$ (83.5)	$ (54.6)	$ (267.9)	$ (91.9)