SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 03, 2021	Jun. 27, 2020	Jun. 29, 2019
Allowance for credit losses:
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves
Balance at Beginning of Period	$ 1.8	$ 4.5	$ 2.6
Assumed in Oclaro Acquisition	0.0	0.0	3.3
Increase (decrease) in Consolidated Statements of Operations	0.2	0.1	(0.2)
Write Offs / Deductions Credited to Expenses or Other Accounts	(1.6)	(2.8)	(1.2)
Balance at End of Period	0.4	1.8	4.5
Deferred tax valuation allowance:
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves
Balance at Beginning of Period	200.8	190.3	99.4
Additions Charged to Expenses or Other Accounts	68.7	12.7	93.5
Write Offs / Deductions Credited to Expenses or Other Accounts	0.0	(2.2)	(2.6)
Balance at End of Period	$ 269.5	$ 200.8	$ 190.3