Goodwill And Acquisition-Related Intangibles, Net (Schedule Of Amortization Of Intangible Assets) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 1	$ 2	$ 4	$ 5
Cost of service and other
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	0	0	0	16
Cost of product
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	1	18	1	27
Operating expenses
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	1	2	4	5
Total amortization
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 2	$ 20	$ 5	$ 48