Investments and Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jun. 28, 2014	Jun. 29, 2013	Jun. 30, 2012
Available-For-Sale Investments
Term of maturities of securities classified as current assets included in short-term investments	12 months
Amortized Cost/ Carrying Cost	$ 588.8	$ 227.7
Gross Unrealized Gains	0.3	0.7
Gross Unrealized Losses	(0.2)	(0.4)
Available for Sale Investments at Fair Value	588.9	228.0
Other-than-temporary impairment loss	0	0	0.3
Gross unrealized losses on available-for-sale securities
Gross unrealized losses, Less than 12 Months		0.1
Gross unrealized losses, Greater than 12 Months	0.2	0.3
Total gross unrealized losses	0.2	0.4
Cash equivalents
Available-For-Sale Investments
Available for Sale Investments at Fair Value	39.8	26.2
Short-term investments
Available-For-Sale Investments
Available for Sale Investments at Fair Value	548.3	201.0
Other non-current assets
Available-For-Sale Investments
Available for Sale Investments at Fair Value	0.8	0.8
Debt securities
Contractual maturities of debt securities classified as available-for-sale securities, Amortized cost
Amortized cost of amounts maturing in less than 1 year	412.5
Amortized cost of amounts maturing in 1-5 years	175.3
Amortized cost of amounts maturing in more than 5 years	1.0
Total amortized cost of debt available-for-sale securities	588.8
Contractual maturities of the debt securities classified as available-for-sale securities, Estimated fair value
Estimated fair value amounts maturing in less than 1 year	412.6
Estimated fair value amounts maturing in 1 -5 years	175.5
Estimated fair value amounts maturing in more than 5 years	0.8
Total estimated fair value of debt available-for-sale securities	588.9
Asset-backed securities
Available-For-Sale Investments
Amortized Cost/ Carrying Cost	94.7	15.5
Gross Unrealized Gains	0.1
Gross Unrealized Losses	(0.2)	(0.3)
Available for Sale Investments at Fair Value	94.6	15.2
Gross unrealized losses on available-for-sale securities
Gross unrealized losses, Greater than 12 Months	0.2	0.3
Total gross unrealized losses	0.2	0.3
U.S. treasuries
Available-For-Sale Investments
Amortized Cost/ Carrying Cost	36.8	12.0
Available for Sale Investments at Fair Value	36.8	12.0
U.S. agencies
Available-For-Sale Investments
Amortized Cost/ Carrying Cost	70.0	52.4
Available for Sale Investments at Fair Value	70.0	52.4
Municipal bonds and sovereign debt instruments
Available-For-Sale Investments
Amortized Cost/ Carrying Cost	16.8	12.7
Available for Sale Investments at Fair Value	16.8	12.7
Corporate securities
Available-For-Sale Investments
Amortized Cost/ Carrying Cost	370.5	135.1
Gross Unrealized Gains	0.2	0.7
Gross Unrealized Losses		(0.1)
Available for Sale Investments at Fair Value	370.7	135.7
Gross unrealized losses on available-for-sale securities
Gross unrealized losses, Less than 12 Months		0.1
Total gross unrealized losses		$ 0.1