Restructuring And Other Charges (Narrative) (Details) (USD $)
In Millions, unless otherwise specified
Mar. 31, 2015
Mar. 31, 2014
Mar. 31, 2013
Mar. 31, 2012
Restructuring And Other Charges        
Restructuring Reserve $ 12 $ 50 $ 62 $ 78
Fiscal Two Thousand And Eleven Restructuring [Member]        
Restructuring And Other Charges        
Restructuring and Related Cost, Cost Incurred to Date 172      
Fiscal Two Thousand And Eleven Restructuring [Member] | Amended Licensing Agreements And Other Asset Impairment [Member]        
Restructuring And Other Charges        
Restructuring and Related Cost, Cost Incurred to Date 129      
Fiscal Two Thousand And Eleven Restructuring [Member] | Developer Commitments [Member]        
Restructuring And Other Charges        
Restructuring and Related Cost, Cost Incurred to Date 31      
Fiscal Two Thousand And Eleven Restructuring [Member] | Employee Severance [Member]        
Restructuring And Other Charges        
Restructuring and Related Cost, Cost Incurred to Date 12      
Fiscal Two Thousand And Eleven Restructuring [Member] | Other Restructuring Costs [Member]        
Restructuring And Other Charges        
Restructuring Reserve 11 47 57 75
Other Restructurings and Reorganization [Member] | Expected By September2016 [Member]        
Restructuring And Other Charges        
Restructuring Reserve 1      
Other Restructurings and Reorganization [Member] | Other Restructuring Costs [Member]        
Restructuring And Other Charges        
Restructuring Reserve $ 0 $ 1 $ 1 $ 0