EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Earnings Per Share [Abstract]
Net income	$ 452.0	$ 1,326.9	$ 1,296.7
Net loss attributable to noncontrolling interests	(8.2)	0.0	0.0
Net income attributable to Olin Corporation	$ 460.2	$ 1,326.9	$ 1,296.7
Basic shares	125.9	144.9	159.1
Earnings per Share, Basic [Abstract]
Basic net income attributable to Olin Corporation per share	$ 3.66	$ 9.16	$ 8.15
Earnings per Share, Diluted [Abstract]
Basic shares	125.9	144.9	159.1
Stock-based compensation (in shares)	2.9	3.6	3.9
Diluted shares	128.8	148.5	163.0
Diluted net income attributable to Olin Corporation per share	$ 3.57	$ 8.94	$ 7.96
Antidilutive shares excluded from the computation of earnings per share (in shares)	1.2	0.8	0.1