Name:	ibm_EmployerContributionAsPercentageOfEligibleCompensationUnderConditionOne
Namespace Prefix:	ibm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the employer's contribution expressed as a percentage of eligible compensation under condition three depending on the employees' eligibility to participate in the PPP as on December 31, 2007.

No definition available.

Name:	ibm_EmployerContributionAsPercentageOfEligibleCompensationUnderConditionThree
Namespace Prefix:	ibm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the employer's contribution expressed as a percentage of eligible compensation under condition two depending on the employees' eligibility to participate in the PPP as on December 31, 2007.

No definition available.

Name:	ibm_EmployerContributionAsPercentageOfEligibleCompensationUnderConditionTwo
Namespace Prefix:	ibm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Minimum amounts that must be invested in company stock.

No definition available.

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

The service period after which employees receive automatic contributions and matching contributions.

No definition available.

Name:	ibm_MinimumServicePeriodAfterWhichEmployeesAreEligibleToReceiveContributions
Namespace Prefix:	ibm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

This element represents maximum percentage of dollar-for-dollar match of employees contribution for those hired after January 1, 2005.

No definition available.

Name:	ibm_PercentageOfEmployeeContributionOnEligibleCompensationForEmployeesHiredPost1stJanuary2005
Namespace Prefix:	ibm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

This element represents maximum percentage of dollar-for-dollar match of employees contribution for those hired prior to January 1, 2005.

No definition available.

Name:	ibm_PercentageOfEmployeeContributionOnEligibleCompensationForEmployeesHiredPrior1stJanuary2005
Namespace Prefix:	ibm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

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.

No definition available.