Severance and Exit Costs 1 (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Accrued severance and exit costs activity
Accrued beginning balance	$ 49	$ 84	$ 39
Accrued ending balance	19	49	84
Severance Charges
Accrued severance and exit costs activity
Accrued beginning balance	28	55	16
Expense	0	60	160
Change in estimate	(3)	(7)	(12)
Payments	(22)	(77)	(113)
Accretion and other	0	(3)	4
Accrued ending balance	3	28	55
Facility Exit Charges
Accrued severance and exit costs activity
Accrued beginning balance	21	29	23
Expense	0	0	22
Change in estimate	0	0	0
Payments	(5)	(9)	(13)
Accretion and other	0	1	(3)
Accrued ending balance	$ 16	$ 21	$ 29