Document and Entity Information (USD $) In Millions, except Share data	12 Months Ended
Mar. 31, 2011	May 08, 2011	Oct. 03, 2010
Document and Entity Information
Entity Registrant Name	ALLIANT TECHSYSTEMS INC
Entity Central Index Key	0000866121
Document Type	10-K
Document Period End Date	Mar. 31, 2011
Amendment Flag	false
Current Fiscal Year End Date	--03-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 2,445
Entity Common Stock, Shares Outstanding		33,552,168
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY

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End date of current fiscal year in the format --MM-DD.

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This is focus fiscal year of the document report in CCYY format. For a 2006 annual report, which may also provide financial information from prior periods, fiscal 2006 should be given as the fiscal year focus. Example: 2006.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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