(Schedule Of Amortization Of Intangible Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 23	$ 9	$ 6
Cost of product
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	3	2	27
Cost of service and other
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	1	0	16
Operating expenses
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	23	9	6
Total amortization
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 27	$ 11	$ 49