Goodwill - Changes in Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jul. 01, 2017
Changes in goodwill
Balance at the beginning of the period	$ 336.3	$ 151.6
Acquisitions	46.1	190.1
Other	3.7
Currency translation and other adjustments	(5.0)	(5.4)
Balance at the end of the period	381.1	336.3
Goodwill balance	1,040.1	995.3
Accumulated impairment losses	659.0	659.0
Network Enablement
Changes in goodwill
Balance at the beginning of the period	328.0	143.3
Acquisitions	12.2	190.1
Other	3.7
Currency translation and other adjustments	(5.0)	(5.4)
Balance at the end of the period	338.9	328.0
Goodwill balance	640.8	629.9	$ 445.2
Accumulated impairment losses	301.9	301.9	301.9
Service Enablement
Changes in goodwill
Balance at the beginning of the period	0.0	0.0
Acquisitions	0.0	0.0
Other	0.0
Currency translation and other adjustments	0.0	0.0
Balance at the end of the period	0.0	0.0
Goodwill balance	272.6	272.6	272.6
Accumulated impairment losses	272.6	272.6	272.6
Optical Security and Performance Products
Changes in goodwill
Balance at the beginning of the period	8.3	8.3
Acquisitions	33.9	0.0
Balance at the end of the period	42.2	8.3
Goodwill balance	126.7	92.8	92.8
Accumulated impairment losses	$ 84.5	$ 84.5	$ 84.5