Goodwill And Acquisition-Related Intangibles, Net (Schedule Of Future Amortization Of Acquisition-Related Intangibles) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Mar. 31, 2018	[1]
Finite-Lived Intangible Assets
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year	$ 12
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	22
Finite-Lived Intangible Assets, Amortization Expense, Year Two	22
Finite-Lived Intangible Assets, Amortization Expense, Year Three	22
Finite-Lived Intangible Assets, Amortization Expense, Year Four	8
Finite-Lived Intangible Assets, Amortization Expense, after Year Five	0
Finite-Lived Intangible Assets, Net	100	$ 71
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year through after Year Five [Member]
Finite-Lived Intangible Assets
Finite-Lived Intangible Assets, Net	$ 86

[1] Derived from audited Consolidated Financial Statements.