Marketable Securities (Summary Of Marketable Securities Classified As Available-For-Sale Securities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Jun. 30, 2011
Gain (Loss) on Investments [Line Items]
Marketable Securities, Cost		$ 30.5
Marketable Securities, Estimated Fair Value		30.5
Government Agency Bonds [Member]
Gain (Loss) on Investments [Line Items]
Marketable Securities, Cost		13.7
Marketable Securities, Estimated Fair Value		13.7
Corporate Bonds [Member]
Gain (Loss) on Investments [Line Items]
Marketable Securities, Cost		15.1
Marketable Securities, Estimated Fair Value		15.1
Commercial Paper [Member]
Gain (Loss) on Investments [Line Items]
Marketable Securities, Cost		1.7
Marketable Securities, Estimated Fair Value		1.7
Municipal Auction Rate Securities [Member]
Gain (Loss) on Investments [Line Items]
Available-for-sale Securities, Cost	6.1	6.1
Marketable Securities, Unrealized Losses	(1.1)	(0.8)
Marketable Securities, Estimated Fair Value	$ 5.0	$ 5.3