This element represents the clients presence in number of countries.

No definition available.

Name:	ibm_ClientsPresenceInNumberOfCountries
Namespace Prefix:	ibm_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the amount of civil penalties chargeable for the Foreign Corrupt Practices Act (FCPA) violations committed.

+ References

No definition available.

+ Details

Name:	ibm_LossContingencyLitigationSettlementCivilPenalty
Namespace Prefix:	ibm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the amount of prejudgment interest, which is included in the total amount of settlement.

+ References

No definition available.

+ Details

Name:	ibm_LossContingencyLitigationSettlementPrejudgmentInterest
Namespace Prefix:	ibm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the amount of profits gained as a result of the conduct alleged in the complaint against the entity, which is included in the total amount of settlement.

+ References

No definition available.

+ Details

Name:	ibm_LossContingencyLitigationSettlementProfitsGainedDueToConductAllegedInTheComplaint
Namespace Prefix:	ibm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the retirement age of employee under the defined benefit plan.

+ References

No definition available.

+ Details

Name:	ibm_RetirementAgeOfEmployeeUnderDefinedBenefitPlan
Namespace Prefix:	ibm_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the retirement age of employee under the defined benefit plan before modifications.

+ References

No definition available.

+ Details

Name:	ibm_RetirementAgeOfEmployeeUnderDefinedBenefitPlanBeforeModifications
Namespace Prefix:	ibm_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Definition

Amount of other defined benefit plan costs.

+ References

No definition available.

+ Details

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

- Definition

The estimated range of reasonably possible losses resulting from an adverse position taken by a taxing authority.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Interpretation (FIN)

-Number 14

-Paragraph 3

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (d)(3)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

+ Details

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

- Definition

This element represents the gross amount awarded, to be received by, or to be remitted to the entity in settlement of litigation occurring during the period.

+ References

No definition available.

+ Details

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

- Details

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

- Definition

The total amount of pending claims pertaining to a loss contingency accrual as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 9, 10, 11, 12

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Name:	us-gaap_LossContingencyPendingClaimsNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Contingencies and Commitments (Details) (USD $) In Millions, unless otherwise specified		1 Months Ended	3 Months Ended		1 Months Ended
	Dec. 31, 2012 item	Oct. 31, 2012 Litigation in United Kingdom regarding defined benefit plans (C Plan) item	Sep. 30, 2012 Litigation in United Kingdom regarding defined benefit plans (C Plan)	Dec. 31, 2012 Former IBM UK Defined Benefit Plan Participants IBM United Kingdom Limited item	Mar. 31, 2011 Civil enforcement action with the SEC IBM Korea, LG IBM, IBM (China) Investment Company Limited and IBM Global Services (China) Co., Ltd.	Jul. 31, 2012 State of Indiana
Contingencies and Commitments
Clients presence in number of countries	170
Loss Contingencies
Amount of settlement to be paid/(received)					$ 10	$ (52)
Claims pending				290
Profits gained as a result of the conduct alleged in the SEC's complaint					5.3
Prejudgment interest					2.7
Civil penalty					2
Additional pre-tax retirement-related obligation recorded			162
Retirement age of employee under the C Plan		60
Retirement age of employee under the C Plan before modifications		63
Income tax examination - Brazil, total potential liability	$ 575