Severance and Exit Costs 1 (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Accrued severance and exit costs activity
Accrued beginning balance				$ 53
Accrued ending balance	49	84	39	53
Severance Charges
Accrued severance and exit costs activity
Accrued beginning balance	55	16	13
Expense	60	160	18
Change in estimate	(7)	(12)	(6)
Payments	(77)	(113)	(9)
Accretion and other	(3)	4	0
Accrued ending balance	28	55	16
Facility Exit Charges
Accrued severance and exit costs activity
Accrued beginning balance	29	23	40
Expense	0	22	0
Change in estimate	0	0	0
Payments	(9)	(13)	(13)
Accretion and other	1	(3)	(4)
Accrued ending balance	$ 21	$ 29	$ 23