Investments and Fair Value Measurements - Assets and Liabilities Measured at Fair Value (Details) - Recurring basis - USD ($) $ in Millions	Jul. 01, 2017	Jul. 02, 2016
Cash and cash equivalents
Assets:
Total assets	$ 789.2	$ 295.4
Short-term investments
Assets:
Total assets	432.2	484.7
Restricted cash
Assets:
Total assets	11.0	11.3
Other current assets
Assets:
Total assets	7.3
Other non-current assets
Assets:
Total assets	5.1	4.5
Other current liabilities
Liability:
Total liabilities	1.3
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total debt available-for-sale securities	56.7	46.1
Marketable equity securities	0.0	171.3
Money market funds	726.4	274.4
Trading securities	2.0	2.4
Foreign currency forward contracts	0.0
Total assets	785.1	494.2
Liability:
Foreign currency forward contracts	0.0	0.0
Total liabilities	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. treasuries
Assets:
Total debt available-for-sale securities	56.7	46.1
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. agencies
Assets:
Total debt available-for-sale securities	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Municipal bonds and sovereign debt instruments
Assets:
Total debt available-for-sale securities	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Asset-backed securities
Assets:
Total debt available-for-sale securities	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate securities
Assets:
Total debt available-for-sale securities	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Certificates of deposit
Assets:
Total debt available-for-sale securities	0.0
Significant Other Observable Inputs (Level 2)
Assets:
Total debt available-for-sale securities	452.4	301.7
Marketable equity securities	0.0	0.0
Money market funds	0.0	0.0
Trading securities	0.0	0.0
Foreign currency forward contracts	7.3
Total assets	459.7	301.7
Liability:
Foreign currency forward contracts	1.3	0.0
Total liabilities	1.3	0.0
Significant Other Observable Inputs (Level 2) | U.S. treasuries
Assets:
Total debt available-for-sale securities	0.0	0.0
Significant Other Observable Inputs (Level 2) | U.S. agencies
Assets:
Total debt available-for-sale securities	44.9	24.9
Significant Other Observable Inputs (Level 2) | Municipal bonds and sovereign debt instruments
Assets:
Total debt available-for-sale securities	4.4	2.0
Significant Other Observable Inputs (Level 2) | Asset-backed securities
Assets:
Total debt available-for-sale securities	71.1	50.2
Significant Other Observable Inputs (Level 2) | Corporate securities
Assets:
Total debt available-for-sale securities	326.0	224.6
Significant Other Observable Inputs (Level 2) | Certificates of deposit
Assets:
Total debt available-for-sale securities	6.0
Total fair value
Assets:
Total debt available-for-sale securities	509.1	347.8
Marketable equity securities	0.0	171.3
Money market funds	726.4	274.4
Trading securities	2.0	2.4
Foreign currency forward contracts	7.3	0.0
Total assets	1,244.8	795.9
Liability:
Foreign currency forward contracts	1.3	0.0
Total liabilities	1.3	0.0
Total fair value | U.S. treasuries
Assets:
Total debt available-for-sale securities	56.7	46.1
Total fair value | U.S. agencies
Assets:
Total debt available-for-sale securities	44.9	24.9
Total fair value | Municipal bonds and sovereign debt instruments
Assets:
Total debt available-for-sale securities	4.4	2.0
Total fair value | Asset-backed securities
Assets:
Total debt available-for-sale securities	71.1	50.2
Total fair value | Corporate securities
Assets:
Total debt available-for-sale securities	326.0	224.6
Total fair value | Certificates of deposit
Assets:
Total debt available-for-sale securities	$ 6.0	$ 0.0