Income Taxes (Schedule Of Unrecognized Tax Benefits) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Operating Loss Carryforwards [Line Items]
Unrecognized tax benefits, beginning balance	$ 274	$ 273
Increases in unrecognized tax benefits related to prior year tax positions	2	7
Decreases in unrecognized tax benefits related to prior year tax positions	(2)	(4)
Increases in unrecognized tax benefits related to current year tax positions	30	58
Decreases in unrecognized tax benefits related to settlements with taxing authorities	0	(1)
Reductions in unrecognized tax benefits due to lapse of applicable statute of limitations	(5)	(54)
Changes in unrecognized tax benefits due to foreign currency translation	(2)	(5)
Unrecognized tax benefits, ending balance	$ 297	$ 274