Financing Arrangement (Carrying Values Of Liability And Equity Components Of Notes) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Mar. 31, 2013
Debt Instruments [Abstract]
Principal amount of Notes	$ 632.5	$ 632.5
Unamortized discount of the liability component	(69)	(74)
Net carrying amount of Notes	564	559	[1]
Equity component, net	$ 105	$ 105

[1] Derived from audited consolidated financial statements.