Income Taxes (Provision for Income Taxes) (Details) (USD $) In Millions	12 Months Ended
	Mar. 31, 2011	Mar. 31, 2010	Mar. 31, 2009
Income Taxes
Federal, current	$ (23)	$ (8)	$ (15)
Federal, deferred	2	(57)	161
Total, federal	(21)	(65)	146
State, current	(6)	2	(2)
State, deferred	3	(4)	76
Total, state	(3)	(2)	74
Foreign, current	23	27	26
Foreign, deferred	(2)	11	(13)
Total, foreign	21	38	13
Total, current	(6)	21	9
Total, deferred	3	(50)	224
Provision for (benefit from) income taxes	$ (3)	$ (29)	$ 233