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

Vacant space, associated with infrastructure reductions and restructuring actions, rental payments within the fifth year of the balance sheet date relating to leases defined as operating.

No definition available.

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

Vacant space, associated with infrastructure reductions and restructuring actions, rental payments within the fourth year of the balance sheet date relating to leases defined as operating.

No definition available.

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

Vacant space, associated with infrastructure reductions and restructuring actions, rental payments within the third year of the balance sheet date relating to leases defined as operating.

No definition available.

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

Vacant space, associated with infrastructure reductions and restructuring actions, rental payments within the second year of the balance sheet date relating to leases defined as operating.

No definition available.

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

Vacant space, associated with infrastructure reductions and restructuring actions, rental payments within, due after the fifth year from the balance sheet date on leases defined as operating.

No definition available.

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

Rental expense including amounts charged to inventories and fixed assets, excluding amounts previously reserved.

No definition available.

Name:	ibm_RentalExpense
Namespace Prefix:	ibm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Contractually required rental payments on leases meeting the criteria for capitalization, due within one year of the balance sheet date.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 16

-Subparagraph a(ii)

-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 840

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6455398&loc=d3e45280-112737

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

Contractually required rental payments on leases meeting the criteria for capitalization, due within the fifth year from the balance sheet date.

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

Contractually required rental payments on leases meeting the criteria for capitalization, due within the fourth year from the balance sheet date.

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

Contractually required rental payments on leases meeting the criteria for capitalization, due within the third year from the balance sheet date.

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

Contractually required rental payments on leases meeting the criteria for capitalization, due within the second year from the balance sheet date.

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

Contractually required rental payments due on leases meeting the criteria for capitalization, after the fifth year from the balance sheet date.

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

This element represents the total of minimum sublease rentals, if any, to be received under noncancelable subleases after the fifth year following the balance sheet date.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 98

-Paragraph 18

-Subparagraph b

-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 840

-SubTopic 40

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6456377&loc=d3e50824-112756

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

This element represents the total of minimum sublease rentals, if any, to be received under noncancelable subleases within the fifth year following the balance sheet date.

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

This element represents the total of minimum sublease rentals, if any, to be received under noncancelable subleases within the fourth year following the balance sheet date.

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

This element represents the total of minimum sublease rentals, if any, to be received under noncancelable subleases within one year of the balance sheet date.

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

This element represents the total of minimum sublease rentals, if any, to be received under noncancelable subleases within the third year following the balance sheet date.

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

This element represents the total of minimum sublease rentals, if any, to be received under noncancelable subleases within the second year following the balance sheet date.

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

- Details

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

- Details

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

- Details

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

For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within one year of the balance sheet date relating to leases defined as operating.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 122

-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 Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 16

-Subparagraph b(i)

-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 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 10

-Section 55

-Paragraph 40

-Subparagraph (Note 3)

-URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717

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

For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within the fifth year of the balance sheet date relating to leases defined as operating.

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

For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within the fourth year of the balance sheet date relating to leases defined as operating.

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

For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within the third year of the balance sheet date relating to leases defined as operating.

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

For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within the second year of the balance sheet date relating to leases defined as operating.

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

For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due after the fifth year from the balance sheet date on leases defined as operating.