The percent of goodwill arising from a business combination that is expected to be deductible for tax purposes.

No definition available.

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- Definition

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275

+ Details

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- 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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- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
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-Publisher FASB
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-Publisher FASB
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-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=116859721&loc=d3e6578-128477

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Balance Type:	credit
Period Type:	duration

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
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-URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

The number of businesses acquired by the entity during the period.

+ References

No definition available.

+ Details

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- Details

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- Details

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Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ibm_CloudAndCognitiveSoftwareMember
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Acquisitions & Divestitures - Businesses Acquired, 2017 (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) entity	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Acquisitions
Goodwill	$ 36,788	$ 58,222	$ 36,265
2017 Acquisitions
Acquisitions
Number of acquisitions \| entity	5
Aggregate acquisitions cost	$ 134
Goodwill	$ 16
Expected percent of goodwill deductible for tax purposes	50.00%
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	6 years 7 months 6 days
2017 Acquisitions \| Global Technology Services
Acquisitions
Goodwill	$ 13
2017 Acquisitions \| Cloud & Cognitive Software
Acquisitions
Goodwill	$ 3