CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Sales	$ 6,833.0	$ 9,376.2	$ 8,910.6
Operating expenses:
Cost of goods sold	5,667.5	7,194.3	6,616.4
Selling and administrative	406.7	393.9	416.9
Restructuring charges	89.6	25.3	27.9
Other operating income	42.9	16.3	1.4
Operating income	712.1	1,779.0	1,850.8
Interest expense	181.1	143.9	348.0
Interest income	4.3	2.2	0.2
Non-operating pension income	24.0	38.7	35.7
Income before taxes	(559.3)	(1,676.0)	(1,538.7)
Income tax provision	107.3	349.1	242.0
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
Net income attributable to Olin Corporation per common share:
Basic	$ 3.66	$ 9.16	$ 8.15
Diluted	$ 3.57	$ 8.94	$ 7.96
Average common shares outstanding:
Basic	125.9	144.9	159.1
Diluted	128.8	148.5	163.0