Derivative Financial Instruments (Schedule Of Derivative Instruments, Gains (Losses) Not Designated As Hedging Instruments) (Details) (Interest And Other Income (Expense), Net [Member], USD $) In Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Interest And Other Income (Expense), Net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	$ 16	$ (7)	$ 14	$ (5)