Valuation And Qualifying Accounts (Details) - Allowance For Doubtful Accounts, Price Protection And Returns [Member] - USD ($) $ in Millions		12 Months Ended
		Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		$ 145	$ 159	$ 140
Charged to Revenue, Costs and Expenses		288	298	269
Charged (Credited) to Other Accounts	[1]	35	(8)	11
Deductions	[2]	(303)	(304)	(261)
Balance at End of Period		$ 165	$ 145	$ 159

[1] Primarily other reclassification adjustments and the translation effect of using the average exchange rate for expense items and the year-end exchange rate for the balance sheet item (allowance account).

[2] Primarily the utilization of returns allowance and price protection reserves.