Financing Arrangement (Schedule Of Interest Expense Related To Notes) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Debt Instruments [Abstract]
Amortization of debt discount	$ (6)	$ (5)	$ (11)	$ (10)
Amortization of debt issuance costs	(1)	(1)	(2)	(2)
Coupon interest expense	(1)	(1)	(2)	(2)
Interest Expense, Other	0	(1)	(1)	(1)
Total interest expense	$ (8)	$ (8)	$ (16)	$ (15)