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