Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011
Income tax expense (benefit)	$ 18.8	$ 3.1	$ 46.0	$ 8.4
Income tax expense as percentage of pre-tax income	36.30%	9.70%	36.30%	15.50%
Prior Year Periods [Member]
Income tax expense (benefit)			$ (4.8)