Financing Arrangement (Schedule Of Interest Expense Related To Notes) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Debt Instruments [Abstract]
Amortization of debt discount	$ 0	$ (3)	$ (2)	$ (14)
Amortization of debt issuance costs	(1)	(1)	(2)	(2)
Coupon interest expense	(10)	(1)	(31)	(3)
Interest Expense, Other	(1)	0	(1)	0
Total interest expense	$ (12)	$ (5)	$ (36)	$ (19)