Goodwill And Acquisition-Related Intangibles, Net (Schedule Of Amortization Of Intangible Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 6	$ 7	$ 14
Cost of product
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	27	14	16
Cost of service and other
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	16	33	36
Operating expenses
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	6	7	14
Total amortization
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 49	$ 54	$ 66