Location of Gain (Loss) Recognized in Income on Derivative, Non-Designated Hedging Instruments (Details) (Interest And Other Income (Expense), Net [Member], USD $)
In Millions, unless otherwise specified
12 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Mar. 31, 2013
Interest And Other Income (Expense), Net [Member]
     
Derivative Instruments, Gain (Loss) [Line Items]      
Foreign currency forward contracts not designated as hedging instruments $ 58 $ (5) $ (2)