Name:	ibm_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRatePostRemeasurementAdjustment
Namespace Prefix:	ibm_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan prior to remeasurement adjustment.

No definition available.

Name:	ibm_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRatePreRemeasurementAdjustment
Namespace Prefix:	ibm_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan, post remeasurement adjustment.

No definition available.

Name:	ibm_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssetsPostRemeasurementAdjustment
Namespace Prefix:	ibm_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

No definition available.

Name:	ibm_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssetsPreRemeasurementAdjustment
Namespace Prefix:	ibm_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Weighted-average interest crediting rate used to determine net periodic benefit cost of defined benefit plan. Plan includes, but is not limited to, cash balance and other defined benefit plans with promised interest crediting rate, post remeasurement adjustment.

No definition available.

Name:	ibm_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostWeightedAverageInterestCreditingRatePostRemeasurementAdjustment
Namespace Prefix:	ibm_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

No definition available.

Name:	ibm_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostWeightedAverageInterestCreditingRatePreRemeasurementAdjustment
Namespace Prefix:	ibm_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

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

Name:	us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_ReclassificationTypeAxis=ibm_RemeasurementPeriodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RetirementPlanSponsorLocationAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RetirementPlanTypeAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: