Recently Issued Accounting Pronouncements - Expected Impact on Balance Sheet (Details) - USD ($) $ in Millions	Jun. 27, 2020	Jun. 30, 2019	Jun. 29, 2019	Jun. 30, 2018	Jul. 01, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
ROU asset	$ 40.5
Lease liabilities	39.8
Adjustment to accumulated deficit	711.4		$ 725.8	$ 734.9	$ 803.5
Property, plant and equipment, net	(172.5)		(179.9)
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
ROU asset		$ 35.5
Lease liabilities		37.0
Financing obligations		10.1
Accumulated Deficit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to accumulated deficit	$ (69,397.2)		$ (69,384.5)	$ (69,378.6)	$ (69,288.5)
Accumulated Deficit | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to accumulated deficit		3.0
Real Estate | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property, plant and equipment, net		$ 7.1