Freeport, TX chlor alkali production capacity reduction announced on December 11, 2019.

No definition available.

Name:	oln_FreeportChlorAlkaliCapacityReduction
Namespace Prefix:	oln_
Data Type:	dtr-types:massItemType
Balance Type:	na
Period Type:	instant

- Definition

Freeport product segment production capacity decrease announced on March 21, 2016

+ References

No definition available.

+ Details

Name:	oln_FreeportProductSegmentProductionCapacityDecrease
Namespace Prefix:	oln_
Data Type:	dtr-types:massItemType
Balance Type:	na
Period Type:	instant

- Definition

Henderson, NV chlor alkali product segment production capacity decrease announced on March 21, 2016

+ References

No definition available.

+ Details

Name:	oln_HendersonProductSegmentProductionCapacityDecrease
Namespace Prefix:	oln_
Data Type:	dtr-types:massItemType
Balance Type:	na
Period Type:	instant

- Definition

Reduction of diaphragm-grade chlor alkali capacity at our McIntosh, AL facility announced in 2021.

+ References

No definition available.

+ Details

Name:	oln_McIntoshRestructuringCapacityReduction
Namespace Prefix:	oln_
Data Type:	dtr-types:massItemType
Balance Type:	na
Period Type:	instant

- Definition

Percent reduction of diaphragm-grade chlor alkali capacity at our McIntosh, AL facility announced in 2021.

+ References

No definition available.

+ Details

Name:	oln_McIntoshRestructuringCapacityReductionPercent
Namespace Prefix:	oln_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Niagara Falls, NY chlor alkali product segment production capacity

+ References

No definition available.

+ Details

Name:	oln_NiagaraProductSegmentProductionCapacity
Namespace Prefix:	oln_
Data Type:	dtr-types:massItemType
Balance Type:	na
Period Type:	instant

- Definition

Reduced Niagara Falls, NY chlor alkali product segment production capacity

+ References

No definition available.

+ Details

Name:	oln_ReducedNiagaraSegmentProductionCapacity
Namespace Prefix:	oln_
Data Type:	dtr-types:massItemType
Balance Type:	na
Period Type:	instant

- Definition

Total chlor alkali product segment production capacity decrease announced on March 21, 2016

+ References

No definition available.

+ Details

Name:	oln_TotalProductSegmentProductionCapacityDecrease
Namespace Prefix:	oln_
Data Type:	dtr-types:massItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI https://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 17
-Subparagraph (f)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3367-108585

+ Details

Name:	us-gaap_PaymentsForRestructuring
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount expected to be recognized in earnings for the specified restructuring cost.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b)(1))
-URI https://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-URI https://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(d))
-URI https://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

+ Details

Name:	us-gaap_RestructuringAndRelatedCostExpectedCost1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 45
-Paragraph 3
-URI https://asc.fasb.org/extlink&oid=109237686&loc=d3e17752-110868

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.P.3)
-URI https://asc.fasb.org/extlink&oid=115931487&loc=d3e140864-122747

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b)(1))
-URI https://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

+ Details

Name:	us-gaap_RestructuringCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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

Name:	us-gaap_RestructuringCostAndReserveLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of decrease in the reserve for full or partial settlement through consideration other than cash.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI https://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b)(2))
-URI https://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

+ Details

Name:	us-gaap_RestructuringReserveSettledWithoutCash2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_RestructuringPlanAxis=oln_ProductivityPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=us-gaap_CorporateAndOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringPlanAxis=oln_McIntoshPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=oln_ChlorAlkaliProductsandVinylsSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringPlanAxis=oln_Freeport2021PlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringPlanAxis=oln_Freeport2019PlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringPlanAxis=oln_ChlorAlkali2016PlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

RESTRUCTURING CHARGES (Details 1) $ in Millions	3 Months Ended						9 Months Ended		18 Months Ended	19 Months Ended	20 Months Ended	34 Months Ended	78 Months Ended
RESTRUCTURING CHARGES (Details 1) $ in Millions	Sep. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2022 USD ($)	Oct. 21, 2021 T	Mar. 15, 2021 T	Dec. 11, 2019 T	Mar. 21, 2016 T
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 7.6	$ 3.6	$ 3.1	$ 3.6	$ 14.0	$ 6.9	$ 14.3	$ 24.5					$ 285.6
Additional restructuring and related expected cost	0.0						0.0		$ 0.0	$ 0.0	$ 0.0	$ 0.0	0.0
Inception to date Amounts Utilized (cash)													137.1
Inception to date Amounts Utilized (non-cash)													141.5
Productivity Plan \| Corporate/other
Restructuring Cost and Reserve [Line Items]
Restructuring charges				0.2				10.3	10.3
Additional restructuring and related expected cost	0.0						0.0		0.0	0.0	0.0	0.0	0.0
McIntosh Plan \| Chlor Alkali Products and Vinyls
Restructuring Cost and Reserve [Line Items]
Restructuring charges	5.5			0.4			7.1	5.2		12.7
Additional restructuring and related expected cost	30.0						30.0		30.0	30.0	30.0	30.0	30.0
McIntosh Restructuring Capacity Reduction Percent														50.00%	50.00%
McIntosh Restructuring Capacity Reduction \| T														200,000	200,000
Freeport 2021 Plan \| Chlor Alkali Products and Vinyls
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.4			1.6			1.9	5.7			8.4
Additional restructuring and related expected cost	20.0						20.0		20.0	20.0	20.0	20.0	20.0
Freeport 2019 Plan \| Chlor Alkali Products and Vinyls
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1.7			1.0			4.9	2.2				71.5
Additional restructuring and related expected cost	30.0						30.0		30.0	30.0	30.0	30.0	30.0
Freeport Chlor Alkali Capacity Reduction \| T																230,000
Chlor Alkali 2016 Plan \| Chlor Alkali Products and Vinyls
Restructuring Cost and Reserve [Line Items]
Restructuring charges				$ 0.4			0.4	$ 1.1					182.7
Additional restructuring and related expected cost	$ 0.0						$ 0.0		$ 0.0	$ 0.0	$ 0.0	$ 0.0	$ 0.0
Total Product Segment Production Capacity Decrease \| T																	433,000
Henderson Product Segment Production Capacity Decrease \| T																	153,000
Niagara Product Segment Production Capacity \| T																	300,000
Reduced Niagara Segment Production Capacity \| T																	240,000
Freeport Product Segment Production Capacity Decrease \| T																	220,000