Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Jan. 31, 2020	Jun. 30, 2019
Cover page.
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	1-1070
Entity Registrant Name	OLIN CORPORATION
Entity Incorporation, State or Country Code	VA
Entity Tax Identification Number	13-1872319
Entity Address, Address Line One	190 Carondelet Plaza,
Entity Address, Address Line Two	Suite 1530,
Entity Address, City or Town	Clayton,
Entity Address, State or Province	MO
Entity Address, Postal Zip Code	63105
City Area Code	314
Local Phone Number	480-1400
Title of 12(b) Security	Common Stock, $1.00 par value per share
Trading Symbol	OLN
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 3,583,520,505
Entity Common Stock, Shares Outstanding (in shares)		157,722,254
Entity Central Index Key	0000074303
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Amendment Flag	false