Quarterly Results (Unaudited) (Details Textual) (USD $) In Millions, unless otherwise specified	3 Months Ended				12 Months Ended
	Jun. 30, 2011	Mar. 31, 2011	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Quarterly Results (Textual) [Abstract]
Net tax benefits related to the settlement of certain tax matters	$ 6.2	$ 25.2	$ 18.0	$ 14.0	$ 6.2	$ 57.2	$ 30.0