Restructuring And Other Charges (Narrative) (Details) (USD $) In Millions, unless otherwise specified				6 Months Ended				6 Months Ended				6 Months Ended				6 Months Ended	24 Months Ended	3 Months Ended			24 Months Ended			6 Months Ended				6 Months Ended	24 Months Ended	6 Months Ended	24 Months Ended
	Sep. 30, 2012	Mar. 31, 2012	Mar. 31, 2011	Sep. 30, 2012 Fiscal 2013 Restructuring	Sep. 30, 2012 Fiscal 2013 Restructuring Facilities-Related	Mar. 31, 2012 Fiscal 2013 Restructuring Facilities-Related	Mar. 31, 2011 Fiscal 2013 Restructuring Facilities-Related	Sep. 30, 2012 Fiscal 2013 Restructuring Facilities-Related Expected by December 31, 2012 [Member]	Sep. 30, 2012 Fiscal 2013 Restructuring Workforce	Mar. 31, 2012 Fiscal 2013 Restructuring Workforce	Mar. 31, 2011 Fiscal 2013 Restructuring Workforce	Sep. 30, 2012 Fiscal 2013 Restructuring License Termination Cost	Sep. 30, 2012 Fiscal 2013 Restructuring Other Reorganizational Cost	Mar. 31, 2012 Fiscal 2013 Restructuring Other Reorganizational Cost	Mar. 31, 2011 Fiscal 2013 Restructuring Other Reorganizational Cost	Sep. 30, 2012 Fiscal 2013 Restructuring Other Reorganizational Cost May 2016	Sep. 30, 2012 Fiscal 2011 Restructuring	Sep. 30, 2012 Fiscal 2011 Restructuring Expected by March 31, 2013	Sep. 30, 2012 Fiscal 2011 Restructuring June 2016	Sep. 30, 2012 Fiscal 2011 Restructuring Expected By June 2016	Sep. 30, 2012 Fiscal 2011 Restructuring Workforce	Mar. 31, 2012 Fiscal 2011 Restructuring Workforce	Mar. 31, 2011 Fiscal 2011 Restructuring Workforce	Sep. 30, 2012 Fiscal 2011 Restructuring Workforce Expected By June 2016	Sep. 30, 2012 Fiscal 2011 Restructuring Other Reorganizational Cost	Mar. 31, 2012 Fiscal 2011 Restructuring Other Reorganizational Cost	Mar. 31, 2011 Fiscal 2011 Restructuring Other Reorganizational Cost	Sep. 30, 2012 Fiscal 2011 Restructuring Amended Licensing Agreements Accretion Of Interest June 2016	Sep. 30, 2012 Fiscal 2011 Restructuring Amended Licensing Agreements And Other Asset Impairment Asset Impairment	Sep. 30, 2012 Fiscal 2011 Restructuring Amended Licensing And Developer Agreements Expected By June 2016	Sep. 30, 2012 Fiscal 2011 Restructuring Amended Developer Agreements	Sep. 30, 2012 Other Restructurings and Reorganization Expected By September 2013	Sep. 30, 2012 Other Restructurings and Reorganization Facilities-Related	Mar. 31, 2012 Other Restructurings and Reorganization Facilities-Related	Mar. 31, 2011 Other Restructurings and Reorganization Facilities-Related	Sep. 30, 2012 Other Restructurings and Reorganization Other Reorganizational Cost	Mar. 31, 2012 Other Restructurings and Reorganization Other Reorganizational Cost	Mar. 31, 2011 Other Restructurings and Reorganization Other Reorganizational Cost
Restructuring And Other Charges
Restructuring incurred charges				$ 22	$ 2				$ 11			$ 9					$ 171				$ 12								$ 128		$ 31
Expected restructuring charges, Minimum																			180
Expected restructuring charges, Maximum																			185
Restructuring reserve and accrual	82	78	117		2	0	0		2	0	0		1	0	0					75	0	0	3		75	75	101					2	2	3	8	0	0	5
Restructuring charges								$ 3								$ 4		$ 3						$ 12				$ 11		$ 170