Income Taxes (Schedule Of Unrecognized Tax Benefits) (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Operating Loss Carryforwards [Line Items]    
Unrecognized tax benefits, beginning balance $ 232 $ 297
Increases in unrecognized tax benefits related to prior year tax positions 9 10
Decreases in unrecognized tax benefits related to prior year tax positions (14) (79)
Increases in unrecognized tax benefits related to current year tax positions 50 44
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities (6) (29)
Reductions in unrecognized tax benefits due to lapse of applicable statute of limitations (7) (9)
Changes in unrecognized tax benefits due to foreign currency translation (10) (2)
Unrecognized tax benefits, ending balance $ 254 $ 232