Contribution to an individual retirement account as a percentage of employee's eligible compensation.

No definition available.

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- Definition

Amount of employer contribution to a defined contribution plan based on employees' eligible compensation.

+ References

No definition available.

+ Details

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Namespace Prefix:	oln_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Amount of discretionary contributions made by an employer to a defined contribution plan.

+ References

No definition available.

+ Details

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- Definition

Percentage employer matches of the employee's percentage contribution matched.

+ References

No definition available.

+ Details

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- Details

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CONTRIBUTING EMPLOYEE OWNERSHIP PLAN (Details) - USD ($) $ in Millions		3 Months Ended		12 Months Ended
	Jan. 01, 2021	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Defined Contribution Plan Disclosure [Line Items]
Defined Contribution Plan Employer Contribution of Eligible Compensation		$ 8.7	$ 8.2
Employer contributions to employee ownership plan				$ 0.0
Employer matching contributions to employee ownership plan		$ 3.2	$ 0.8
Minimum
Defined Contribution Plan Disclosure [Line Items]
Contribution To Individual Retirement Account Percentage Of Employees Eligible Compensation		5.00%
Maximum
Defined Contribution Plan Disclosure [Line Items]
Contribution To Individual Retirement Account Percentage Of Employees Eligible Compensation		7.50%
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	3.00%