Goodwill And Acquisition-Related Intangibles, Net (Schedule Of Amortization Of Intangible Assets) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 2	$ 1	$ 3	$ 3
Cost of service and other
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	0	8	0	16
Cost of product
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	0	4	0	9
Operating expenses
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	2	1	3	3
Total amortization
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 2	$ 13	$ 3	$ 28