Investments and Fair Value Measurements (Details 3) - USD ($) $ in Millions	6 Months Ended
	Jan. 02, 2016	Dec. 27, 2014
Maximum
Foreign Currency Forward Contracts
Foreign currency forward contracts, expiration period	120 days	120 days
Recurring basis | Total fair value
Fair Value Measurements
Total debt available-for-sale securities	$ 341.2
Marketable equity securities	257.5
Money market funds	203.0
Trading securities	3.3
Total assets	805.0
Recurring basis | Cash and cash equivalents
Fair Value Measurements
Total assets	204.5
Recurring basis | Short-term investments
Fair Value Measurements
Total assets	585.5
Recurring basis | Restricted cash
Fair Value Measurements
Total assets	10.5
Recurring basis | Other non-current assets
Fair Value Measurements
Total assets	4.5
Recurring basis | U.S. treasuries | Total fair value
Fair Value Measurements
Total debt available-for-sale securities	46.3
Recurring basis | U.S. agencies | Total fair value
Fair Value Measurements
Total debt available-for-sale securities	59.6
Recurring basis | Municipal bonds and sovereign debt instruments | Total fair value
Fair Value Measurements
Total debt available-for-sale securities	2.3
Recurring basis | Asset-backed securities | Total fair value
Fair Value Measurements
Total debt available-for-sale securities	49.4
Recurring basis | Corporate securities | Total fair value
Fair Value Measurements
Total debt available-for-sale securities	183.6
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value Measurements
Total debt available-for-sale securities	46.3
Marketable equity securities	257.5
Money market funds	203.0
Trading securities	3.3
Total assets	510.1
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. treasuries
Fair Value Measurements
Total debt available-for-sale securities	46.3
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. agencies
Fair Value Measurements
Total debt available-for-sale securities	0.0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Municipal bonds and sovereign debt instruments
Fair Value Measurements
Total debt available-for-sale securities	0.0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Asset-backed securities
Fair Value Measurements
Total debt available-for-sale securities	0.0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate securities
Fair Value Measurements
Total debt available-for-sale securities	0.0
Recurring basis | Significant Other Observable Inputs (Level 2)
Fair Value Measurements
Total debt available-for-sale securities	294.9
Marketable equity securities	0.0
Money market funds	0.0
Trading securities	0.0
Total assets	294.9
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. treasuries
Fair Value Measurements
Total debt available-for-sale securities	0.0
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. agencies
Fair Value Measurements
Total debt available-for-sale securities	59.6
Recurring basis | Significant Other Observable Inputs (Level 2) | Municipal bonds and sovereign debt instruments
Fair Value Measurements
Total debt available-for-sale securities	2.3
Recurring basis | Significant Other Observable Inputs (Level 2) | Asset-backed securities
Fair Value Measurements
Total debt available-for-sale securities	49.4
Recurring basis | Significant Other Observable Inputs (Level 2) | Corporate securities
Fair Value Measurements
Total debt available-for-sale securities	$ 183.6