Investments, Forward Contracts and Fair Value Measurements - Measured at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2016	Jul. 02, 2016
Cash and cash equivalents
Assets:
Total assets		$ 295.4
Short-term investments
Assets:
Total assets		484.7
Restricted cash
Assets:
Total assets		11.3
Other non-current assets
Assets:
Total assets		4.5
Other current liabilities
Liability:
Total liabilities	$ 9.6
Recurring basis | Cash and cash equivalents
Assets:
Total assets	314.0
Recurring basis | Short-term investments
Assets:
Total assets	498.0
Recurring basis | Restricted cash
Assets:
Total assets	11.0
Recurring basis | Other non-current assets
Assets:
Total assets	4.8
Recurring basis | Prepayments and other current assets
Assets:
Total assets	4.0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total debt available-for-sale securities	67.5	46.1
Marketable equity securities	64.3	171.3
Money market funds	283.1	274.4
Trading securities	2.5	2.4
Foreign currency forward contracts	0.0	0.0
Total assets	417.4	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	67.5	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 deposits
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	410.4	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	4.0	0.0
Total assets	414.4	301.7
Liability:
Foreign currency forward contracts	9.6	0.0
Total liabilities	9.6	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	36.4	24.9
Recurring basis | Significant Other Observable Inputs (Level 2) | Municipal bonds and sovereign debt instruments
Assets:
Total debt available-for-sale securities	3.5	2.0
Recurring basis | Significant Other Observable Inputs (Level 2) | Asset-backed securities
Assets:
Total debt available-for-sale securities	62.6	50.2
Recurring basis | Significant Other Observable Inputs (Level 2) | Corporate securities
Assets:
Total debt available-for-sale securities	301.9	224.6
Recurring basis | Significant Other Observable Inputs (Level 2) | Certificates of deposits
Assets:
Total debt available-for-sale securities	6.0	0.0
Recurring basis | Total fair value
Assets:
Total debt available-for-sale securities	477.9	347.8
Marketable equity securities	64.3	171.3
Money market funds	283.1	274.4
Trading securities	2.5	2.4
Foreign currency forward contracts	4.0	0.0
Total assets	831.8	795.9
Liability:
Foreign currency forward contracts	9.6	0.0
Total liabilities	9.6	0.0
Recurring basis | Total fair value | U.S. treasuries
Assets:
Total debt available-for-sale securities	67.5	46.1
Recurring basis | Total fair value | U.S. agencies
Assets:
Total debt available-for-sale securities	36.4	24.9
Recurring basis | Total fair value | Municipal bonds and sovereign debt instruments
Assets:
Total debt available-for-sale securities	3.5	2.0
Recurring basis | Total fair value | Asset-backed securities
Assets:
Total debt available-for-sale securities	62.6	50.2
Recurring basis | Total fair value | Corporate securities
Assets:
Total debt available-for-sale securities	301.9	224.6
Recurring basis | Total fair value | Certificates of deposits
Assets:
Total debt available-for-sale securities	$ 6.0	$ 0.0