Name:	ibm_DefinedBenefitPlanPlansWithPlanAssetsInExcessOfBenefitObligationAggregateBenefitObligation
Namespace Prefix:	ibm_
Data Type:	xbrli:monetaryItemType
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If aggregate disclosures are presented, the aggregate fair value of plan assets for plans with plan assets in excess of the benefit obligation as of the measurement date of each statement of financial position presented.

No definition available.

Name:	ibm_DefinedBenefitPlanPlansWithPlanAssetsInExcessOfBenefitObligationAggregateFairValueOfPlanAssets
Namespace Prefix:	ibm_
Data Type:	xbrli:monetaryItemType
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It represents the amount of defined benefit plan with accumulated postretirement benefit obligation in excess of plan assets accumulated benefit obligation.

No definition available.

Name:	ibm_DefinedBenefitPlanWithAccumulatedPostretirementBenefitObligationInExcessOfPlanAssetsAccumulatedBenefitObligation
Namespace Prefix:	ibm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

It represents the amount of defined benefit plan with accumulated postretirement benefit obligation in excess of plan assets plan assets.

No definition available.

Name:	ibm_DefinedBenefitPlanWithAccumulatedPostretirementBenefitObligationInExcessOfPlanAssetsPlanAssets
Namespace Prefix:	ibm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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It represents the amount of defined benefit plan with plan assets in excess of accumulated postretirement benefit obligation accumulated benefit obligation.

No definition available.

Name:	ibm_DefinedBenefitPlanWithPlanAssetsInExcessOfAccumulatedPostretirementBenefitObligationAccumulatedBenefitObligation
Namespace Prefix:	ibm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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It represents the amount of defined benefit plan with plan assets in excess of accumulated postretirement benefit obligation plan assets.

No definition available.

Name:	ibm_DefinedBenefitPlanWithPlanAssetsInExcessOfAccumulatedPostretirementBenefitObligationPlanAssets
Namespace Prefix:	ibm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of plan asset for defined benefit pension plan with projected benefit obligation in excess of plan assets.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount of projected benefit obligation for defined benefit pension plan with projected benefit obligation in excess of plan assets.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
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Amount of accumulated benefit obligation for defined benefit plan with accumulated benefit obligation in excess of plan assets.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e2417-114920

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
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-Publisher FASB
-Name Accounting Standards Codification
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Name:	us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of plan asset for defined benefit plan with accumulated benefit obligation in excess of plan assets.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e2417-114920

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
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-URI http://asc.fasb.org/extlink&oid=123450688&loc=d3e4179-114921

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e2417-114920