Financing Arrangement (Schedule Of Interest Expense Related To Notes) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Debt Instruments [Abstract]
Amortization of debt discount	$ (1)	$ (5)	$ (2)	$ (11)
Amortization of debt issuance costs	0	0	(1)	(1)
Coupon interest expense	(10)	(1)	(21)	(2)
Total interest expense	$ (11)	$ (6)	$ (24)	$ (14)