Marketable Securities (Tables)

6 Months Ended

Dec. 31, 2011

Marketable Securities [Abstract]

Summary Of Marketable Securities Classified As Available-For-Sale Securities

		Fair Value		Fair Value			Fair Value
December 31, 2011			Unrealized Losses			Estimated Fair Value
($ in millions)	Cost
Non-current
Municipal auction rate securities	$	6.1	$	(1.1	)	$	5.0

		Fair Value		Fair Value			Fair Value
June 30, 2011			Unrealized Losses			Estimated Fair Value
($ in millions)	Cost
Current
Government agency bonds	$	13.7	$	—		$	13.7
Corporate bonds		15.1		—			15.1
Commercial paper		1.7		—			1.7
	$	30.5	$	—		$	30.5
Non-current
Municipal auction rate securities	$	6.1	$	(0.8	)	$	5.3