Restructuring And Other Charges (Restructuring And Other Restructuring Plan-Related Information) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended						12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Restructuring And Other Charges [Line Items]
Beginning balance			$ 78			$ 117	$ 78	$ 117	$ 29
Charges to operations	(2)	2	(27)	1	1	(18)	27	16	161
Charges settled in cash							(36)	(55)	(70)
Charges settled in non-cash							(7)		(3)
Ending balance				78			62	78	117
Fiscal 2013 Restructuring [Member] | Workforce [Member]
Restructuring And Other Charges [Line Items]
Beginning balance			0				0
Charges to operations							10
Charges settled in cash							(10)
Charges settled in non-cash							0
Ending balance							0
Fiscal 2013 Restructuring [Member] | Facilities-Related [Member]
Restructuring And Other Charges [Line Items]
Beginning balance			0				0
Charges to operations							3
Charges settled in cash							0
Charges settled in non-cash							(1)
Ending balance							2
Fiscal 2013 Restructuring [Member] | Other Restructuring Costs [Member]
Restructuring And Other Charges [Line Items]
Beginning balance			0				0
Charges to operations							9
Charges settled in cash							(1)
Charges settled in non-cash							(7)
Ending balance							1
Fiscal 2011 Restructuring [Member] | Workforce [Member]
Restructuring And Other Charges [Line Items]
Beginning balance						3		3	0
Charges to operations								(1)	13
Charges settled in cash								(2)	(8)
Charges settled in non-cash									(2)
Ending balance				0				0	3
Fiscal 2011 Restructuring [Member] | Other Restructuring Costs [Member]
Restructuring And Other Charges [Line Items]
Beginning balance			75			101	75	101	0
Charges to operations							6	21	135
Charges settled in cash							(24)	(47)	(32)
Charges settled in non-cash							0		(2)
Ending balance				75			57	75	101
Other Restructurings And Reorganization [Member] | Workforce [Member]
Restructuring And Other Charges [Line Items]
Beginning balance									8
Charges to operations									0
Charges settled in cash									(8)
Charges settled in non-cash									0
Ending balance									0
Other Restructurings And Reorganization [Member] | Facilities-Related [Member]
Restructuring And Other Charges [Line Items]
Beginning balance			3			8	3	8	14
Charges to operations							(1)	(12)	0
Charges settled in cash							(1)	7	(7)
Charges settled in non-cash							1		1
Ending balance				3			2	3	8
Other Restructurings And Reorganization [Member] | Other Restructuring and Reorganizational Cost [Member]
Restructuring And Other Charges [Line Items]
Beginning balance						5		5	7
Charges to operations								8	13
Charges settled in cash								(13)	(15)
Charges settled in non-cash									0
Ending balance				$ 0				$ 0	$ 5