Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
	Aug. 01, 2015	Apr. 02, 2016	Mar. 28, 2015	Apr. 02, 2016	Mar. 28, 2015
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period				$ 1,101.4
Transfer to Lumentum	$ (7.8)			(7.8)
Other comprehensive (loss) income before reclassification				183.2
Amounts reclassified from accumulated other comprehensive income (loss)				(38.3)
Net change in Accumulated other comprehensive income (loss)		$ 13.3	$ (26.9)	144.9	$ (63.0)
Balance at the end of the period		$ 837.4		837.4
Tax impact of amortization of actuarial losses				0.0
Lumentum
Changes in accumulated other comprehensive income (loss) by component
Shares held in investment (in shares)	11.7
Marketable equity securities
Changes in accumulated other comprehensive income (loss) by component
Number of shares sold (in shares)		2.5
Marketable equity securities | Lumentum
Changes in accumulated other comprehensive income (loss) by component
Unrealized gain on marketable equity securities				205.3
Income tax expense impact from unrealized holding gains on marketable equity securities				3.7
Realized gain on sale of marketable equity securities		$ 39.7
Number of shares sold (in shares)		2.5
Shares held in investment (in shares)	11.7
Income tax expense impact from realized gain on sale of marketable equity securities		$ 1.0
Total
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period				(48.0)
Balance at the end of the period		89.1		89.1
Unrealized gains (losses) on available-for-sale investments
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period				(3.2)
Transfer to Lumentum				0.0
Other comprehensive (loss) income before reclassification				201.6
Amounts reclassified from accumulated other comprehensive income (loss)				(38.8)
Net change in Accumulated other comprehensive income (loss)				162.8
Balance at the end of the period		159.6		159.6
Foreign currency translation adjustments
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period				(29.2)
Transfer to Lumentum				(8.9)
Other comprehensive (loss) income before reclassification				(18.4)
Amounts reclassified from accumulated other comprehensive income (loss)				0.0
Net change in Accumulated other comprehensive income (loss)				(18.4)
Balance at the end of the period		(56.5)		(56.5)
Defined benefit obligation, net of tax
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period				(15.6)
Transfer to Lumentum				1.1
Other comprehensive (loss) income before reclassification				0.0
Amounts reclassified from accumulated other comprehensive income (loss)				0.5
Net change in Accumulated other comprehensive income (loss)				0.5
Balance at the end of the period		$ (14.0)		$ (14.0)