Document And Entity Information (USD $)	9 Months Ended
	Sep. 30, 2011	Jun. 30, 2010
Entity Registrant Name	Olin Corporation
Entity Central Index Key	0000074303
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float		$ 1,426,484,996
Entity Common Stock, Shares Outstanding	80,162,837
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2011