Amount of retained interest transferred to a third-party financial institution pursuant to an exchange agreement.

No definition available.

Name:	ibm_AmountOfRetainedInterestTransferred
Namespace Prefix:	ibm_
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Period Type:	duration

- Definition

Ratio applied to the conversion of stock.

+ References

No definition available.

+ Details

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Namespace Prefix:	ibm_
Data Type:	xbrli:pureItemType
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- Definition

The amount of separation costs of discontinued operations.

+ References

No definition available.

+ Details

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

- Definition

The period in which the transition services to be given by the company after separation.

+ References

No definition available.

+ Details

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

- Definition

The period in which the upgraded hardware to be provided by the company after separation.

+ References

No definition available.

+ Details

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

- Definition

Amount of gain loss on sale of interest in joint venture.

+ References

No definition available.

+ Details

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

- Definition

Percentage of retained interest in investment transferred.

+ References

No definition available.

+ Details

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

- Definition

Numbers shares transferred.

+ References

No definition available.

+ Details

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Namespace Prefix:	ibm_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the percentage of Kyndryl publicly traded common stock distributed to IBM stockholders of record as of 10/25/2021

+ References

No definition available.

+ Details

Name:	ibm_PercentageOfKyndrylStockDistributionToIbmStockholders
Namespace Prefix:	ibm_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

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

- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	dei_LegalEntityAxis=ibm_KyndrylHoldingsIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

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- Details

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Data Type:	na
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- Details

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- Details

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Data Type:	na
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Separation of Kyndryl (Details) shares in Millions, $ in Millions			3 Months Ended		9 Months Ended
	May 23, 2022	May 19, 2022 shares	Mar. 31, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Nov. 03, 2021
Discontinued Operations
Numbers shares transferred \| shares		22.3
Kyndryl Holdings, Inc
Discontinued Operations
Kyndryl stock distributed to IBM stockholders							80.10%
Share conversion ratio							0.2
Upgraded hardware period					2 years
Kyndryl Holdings, Inc \| Maximum
Discontinued Operations
Transition services period					2 years
Kyndryl Holdings, Inc
Discontinued Operations
Ownership interest by stockholders (in percent)							19.90%
Amount of retained interest transferred	9.95%
Percentage of retained interest in investment transferred					100.00%
Pre-tax gain on sale			$ 68
Kyndryl Holdings, Inc \| Kyndryl Holdings, Inc
Discontinued Operations
Kyndryl stock distributed to IBM stockholders							80.10%
Managed infrastructure services unit \| Disposed by separation
Discontinued Operations
Separation costs				$ 543	$ 5	$ 739