Net Loss Per Share (Narrative) (Details) (USD $) In Millions, except Per Share data	12 Months Ended
Mar. 31, 2011	Mar. 31, 2010	Mar. 31, 2009
Net Loss Per Share
Dilutive instruments excluded from net loss per share	4	2	4
Antidilutive securities excluded from net loss per share	17	32	28
Weighted-average exercise price of outstanding antidilutive securities	$ 25.36	$ 32.89	$ 44.59

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) in the future that were not included in the computation of diluted EPS because to do so would increase EPS amounts or decrease loss per share amounts for the period presented.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 13, 14

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 171

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 40
-Subparagraph c

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Namespace Prefix:	us-gaap
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration