Investments, Forward Contracts and Fair Value Measurements - Measured at Fair Value (Details) - USD ($) $ in Millions	Apr. 01, 2017	Jul. 02, 2016
Other current liabilities
Liability:
Total liabilities	$ 2.6
Recurring basis | Cash and cash equivalents
Assets:
Total assets	754.6	$ 295.4
Recurring basis | Short-term investments
Assets:
Total assets	478.6	484.7
Recurring basis | Restricted cash
Assets:
Total assets	11.7	11.3
Recurring basis | Prepayments and other current assets
Assets:
Total assets	5.2
Recurring basis | Other non-current assets
Assets:
Total assets	4.5	4.5
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total debt available-for-sale securities	69.5	46.1
Marketable equity securities	20.8	171.3
Money market funds	720.3	274.4
Trading securities	2.0	2.4
Foreign currency forward contracts	0.0	0.0
Total assets	812.6	494.2
Liability:
Foreign currency forward contracts	0.0	0.0
Total liabilities	0.0	0.0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. treasuries
Assets:
Total debt available-for-sale securities	69.5	46.1
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. agencies
Assets:
Total debt available-for-sale securities	0.0	0.0
Recurring basis | 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
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Asset-backed securities
Assets:
Total debt available-for-sale securities	0.0	0.0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate securities
Assets:
Total debt available-for-sale securities	0.0	0.0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Certificates of deposit
Assets:
Total debt available-for-sale securities	0.0	0.0
Recurring basis | Significant Other Observable Inputs (Level 2)
Assets:
Total debt available-for-sale securities	436.8	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	5.2	0.0
Total assets	442.0	301.7
Liability:
Foreign currency forward contracts	2.6	0.0
Total liabilities	2.6	0.0
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. treasuries
Assets:
Total debt available-for-sale securities	0.0	0.0
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. agencies
Assets:
Total debt available-for-sale securities	35.1	24.9
Recurring basis | Significant Other Observable Inputs (Level 2) | Municipal bonds and sovereign debt instruments
Assets:
Total debt available-for-sale securities	4.0	2.0
Recurring basis | Significant Other Observable Inputs (Level 2) | Asset-backed securities
Assets:
Total debt available-for-sale securities	67.7	50.2
Recurring basis | Significant Other Observable Inputs (Level 2) | Corporate securities
Assets:
Total debt available-for-sale securities	324.0	224.6
Recurring basis | Significant Other Observable Inputs (Level 2) | Certificates of deposit
Assets:
Total debt available-for-sale securities	6.0	0.0
Recurring basis | Total
Assets:
Total debt available-for-sale securities	506.3	347.8
Marketable equity securities	20.8	171.3
Money market funds	720.3	274.4
Trading securities	2.0	2.4
Foreign currency forward contracts	5.2	0.0
Total assets	1,254.6	795.9
Liability:
Foreign currency forward contracts	2.6	0.0
Total liabilities	2.6	0.0
Recurring basis | Total | U.S. treasuries
Assets:
Total debt available-for-sale securities	69.5	46.1
Recurring basis | Total | U.S. agencies
Assets:
Total debt available-for-sale securities	35.1	24.9
Recurring basis | Total | Municipal bonds and sovereign debt instruments
Assets:
Total debt available-for-sale securities	4.0	2.0
Recurring basis | Total | Asset-backed securities
Assets:
Total debt available-for-sale securities	67.7	50.2
Recurring basis | Total | Corporate securities
Assets:
Total debt available-for-sale securities	324.0	224.6
Recurring basis | Total | Certificates of deposit
Assets:
Total debt available-for-sale securities	$ 6.0	$ 0.0