CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 452.0	$ 1,326.9	$ 1,296.7
Other comprehensive (loss) income, net of tax:
Foreign currency translation	(1.1)	(27.7)	(30.3)
Cash flow hedges	14.1	(55.3)	1.4
Pension and postretirement benefits	(13.4)	75.1	230.8
Total other comprehensive (loss) income, net of tax	(0.4)	(7.9)	201.9
Comprehensive income	451.6	1,319.0	1,498.6
Comprehensive loss attributable to noncontrolling interests	(8.2)	0.0	0.0
Comprehensive income attributable to Olin Corporation	$ 459.8	$ 1,319.0	$ 1,498.6