Investments and Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Mar. 30, 2013	Mar. 31, 2012	Mar. 30, 2013	Mar. 31, 2012	Jun. 30, 2012
Available-For-Sale Investments
Term of maturities of securities classified as current assets included in short-term investments	12 months		12 months		12 months
Amortized Cost/ Carrying Cost	$ 366.9		$ 366.9		$ 337.3
Gross Unrealized Gains	2.3		2.3		1.7
Gross Unrealized Losses	(0.9)		(0.9)		(0.5)
Available for Sale Investments at Fair Value	368.3		368.3		338.5
Other-than-temporary impairment loss	0	0.3	0	0.3
Gross unrealized losses on available-for-sale securities
Gross unrealized losses, Less than 12 Months	0.4		0.4		0.1
Gross unrealized losses, Greater than 12 Months	0.5		0.5		0.4
Total gross unrealized losses	0.9		0.9		0.5
Cash and cash equivalents
Available-For-Sale Investments
Available for Sale Investments at Fair Value	21.3		21.3		21.3
Short-term investments
Available-For-Sale Investments
Available for Sale Investments at Fair Value	346.2		346.2		315.9
Other non-current assets
Available-For-Sale Investments
Available for Sale Investments at Fair Value	0.8		0.8		1.3
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	199.9		199.9
Amortized cost of amounts maturing in 1-5 years	166.0		166.0
Amortized cost of amounts maturing more than 5 years	1.0		1.0
Total amortized cost of debt available-for-sale securities	366.9		366.9
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	201.5		201.5
Estimated fair value amounts maturing in 1 -5 years	166.0		166.0
Estimated fair value amounts maturing in more than 5 years	0.8		0.8
Total estimated fair value of debt available-for-sale securities	368.3		368.3
Asset-backed securities
Available-For-Sale Investments
Amortized Cost/ Carrying Cost	39.0		39.0		21.9
Gross Unrealized Gains					0.2
Gross Unrealized Losses	(0.3)		(0.3)		(0.4)
Available for Sale Investments at Fair Value	38.7		38.7		21.7
Gross unrealized losses on available-for-sale securities
Gross unrealized losses, Greater than 12 Months	0.3		0.3		0.4
Total gross unrealized losses	0.3		0.3		0.4
U.S. treasuries
Available-For-Sale Investments
Amortized Cost/ Carrying Cost	30.6		30.6		52.0
Available for Sale Investments at Fair Value	30.6		30.6		52.0
U.S. Agencies
Available-For-Sale Investments
Amortized Cost/ Carrying Cost	53.4		53.4		65.1
Gross Unrealized Gains	0.1		0.1		0.2
Available for Sale Investments at Fair Value	53.5		53.5		65.3
Foreign Agencies
Available-For-Sale Investments
Amortized Cost/ Carrying Cost					3.3
Available for Sale Investments at Fair Value					3.3
Municipal bonds and sovereign debt instruments
Available-For-Sale Investments
Amortized Cost/ Carrying Cost	10.3		10.3		11.4
Gross Unrealized Losses	(0.1)		(0.1)
Available for Sale Investments at Fair Value	10.2		10.2		11.4
Gross unrealized losses on available-for-sale securities
Gross unrealized losses, Less than 12 Months	0.1		0.1
Total gross unrealized losses	0.1		0.1
Corporate securities
Available-For-Sale Investments
Amortized Cost/ Carrying Cost	233.6		233.6		183.6
Gross Unrealized Gains	2.2		2.2		1.3
Gross Unrealized Losses	(0.5)		(0.5)		(0.1)
Available for Sale Investments at Fair Value	235.3		235.3		184.8
Gross unrealized losses on available-for-sale securities
Gross unrealized losses, Less than 12 Months	0.3		0.3		0.1
Gross unrealized losses, Greater than 12 Months	0.2		0.2
Total gross unrealized losses	$ 0.5		$ 0.5		$ 0.1