Investments, Forward Contracts and Fair Value Measurements - Measured at Fair Value (Details) - USD ($) $ in Millions	Dec. 30, 2017	Jul. 01, 2017
Debt available-for-sale securities
Total debt available-for-sale securities	$ 511.3
U.S. treasuries
Debt available-for-sale securities
Total debt available-for-sale securities	94.0
U.S. agencies
Debt available-for-sale securities
Total debt available-for-sale securities	22.9
Municipal bonds and sovereign debt instruments
Debt available-for-sale securities
Total debt available-for-sale securities	2.9
Asset-backed securities
Debt available-for-sale securities
Total debt available-for-sale securities	55.5
Corporate securities
Debt available-for-sale securities
Total debt available-for-sale securities	336.0
Recurring basis
Debt available-for-sale securities
Total debt available-for-sale securities	511.3	$ 509.1
Money market funds	479.9	726.4
Trading securities	2.2	2.0
Foreign currency forward contracts	1.9	7.3
Total assets	995.3	1,244.8
Liability:
Foreign currency forward contracts	0.8	1.3
Total liabilities	0.8	1.3
Recurring basis \| Cash and cash equivalents
Debt available-for-sale securities
Total assets	529.0	789.2
Recurring basis \| Short-term investments
Debt available-for-sale securities
Total assets	452.3	432.2
Recurring basis \| Restricted cash
Debt available-for-sale securities
Total assets	7.2	11.0
Recurring basis \| Prepayments and other current assets
Debt available-for-sale securities
Total assets	1.9
Recurring basis \| Other current assets
Debt available-for-sale securities
Total assets		7.3
Recurring basis \| Other non-current assets
Debt available-for-sale securities
Total assets	4.9	5.1
Recurring basis \| Other current liabilities
Liability:
Total liabilities	0.8	1.3
Recurring basis \| U.S. treasuries
Debt available-for-sale securities
Total debt available-for-sale securities	94.0	56.7
Recurring basis \| U.S. agencies
Debt available-for-sale securities
Total debt available-for-sale securities	22.9	44.9
Recurring basis \| Municipal bonds and sovereign debt instruments
Debt available-for-sale securities
Total debt available-for-sale securities	2.9	4.4
Recurring basis \| Asset-backed securities
Debt available-for-sale securities
Total debt available-for-sale securities	55.5	71.1
Recurring basis \| Corporate securities
Debt available-for-sale securities
Total debt available-for-sale securities	336.0	326.0
Recurring basis \| Certificates of deposit
Debt available-for-sale securities
Total debt available-for-sale securities	0.0	6.0
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Debt available-for-sale securities
Total debt available-for-sale securities	94.0	56.7
Money market funds	479.9	726.4
Trading securities	2.2	2.0
Foreign currency forward contracts	0.0	0.0
Total assets	576.1	785.1
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
Debt available-for-sale securities
Total debt available-for-sale securities	94.0	56.7
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| U.S. agencies
Debt available-for-sale securities
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
Debt available-for-sale securities
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
Debt available-for-sale securities
Total debt available-for-sale securities	0.0	0.0
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Corporate securities
Debt available-for-sale securities
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
Debt available-for-sale securities
Total debt available-for-sale securities	0.0	0.0
Recurring basis \| Significant Other Observable Inputs (Level 2)
Debt available-for-sale securities
Total debt available-for-sale securities	417.3	452.4
Money market funds	0.0	0.0
Trading securities	0.0	0.0
Foreign currency forward contracts	1.9	7.3
Total assets	419.2	459.7
Liability:
Foreign currency forward contracts	0.8	1.3
Total liabilities	0.8	1.3
Recurring basis \| Significant Other Observable Inputs (Level 2) \| U.S. treasuries
Debt available-for-sale securities
Total debt available-for-sale securities	0.0	0.0
Recurring basis \| Significant Other Observable Inputs (Level 2) \| U.S. agencies
Debt available-for-sale securities
Total debt available-for-sale securities	22.9	44.9
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Municipal bonds and sovereign debt instruments
Debt available-for-sale securities
Total debt available-for-sale securities	2.9	4.4
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Asset-backed securities
Debt available-for-sale securities
Total debt available-for-sale securities	55.5	71.1
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Corporate securities
Debt available-for-sale securities
Total debt available-for-sale securities	336.0	326.0
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Certificates of deposit
Debt available-for-sale securities
Total debt available-for-sale securities	$ 0.0	$ 6.0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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-Name Accounting Standards Codification
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Amount of debt securities categorized neither as held-to-maturity nor trading.

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Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

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Amount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

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