EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Earnings Per Share [Abstract]
Net income	$ 47.8	$ 154.0
Net loss attributable to noncontrolling interests	(0.8)	(2.3)
Net income attributable to Olin Corporation	$ 48.6	$ 156.3
Basic shares	119.9	131.0
Basic net income attributable to Olin Corporation per share	$ 0.41	$ 1.19
Earnings Per Share, Diluted [Abstract]
Basic shares	119.9	131.0
Stock-based compensation	2.0	3.4
Diluted shares	121.9	134.4
Diluted net income attributable to Olin Corporation per share	$ 0.40	$ 1.16
Antidilutive Securities Excluded from Computation of Earnings Per Share, Shares	2.0	1.4