The aggregate of property, plant and equipment and other noncurrent assets recognized as of the acquisition date.

No definition available.

Name:	ibm_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipmentAndOtherNoncurrentAssets
Namespace Prefix:	ibm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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

Name:	us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- 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

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

- Definition

Amount of assets acquired at the acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=73530397&loc=d3e4845-128472

+ Details

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

- Definition

Amount of assets that are expected to be realized or consumed within one year or the normal operating cycle, if longer, acquired at the acquisition date.

+ References

+ Details

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

- Definition

Amount of liabilities due within one year or within the normal operating cycle, if longer, assumed at the acquisition date.

+ References

+ Details

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

- Definition

Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

+ References

+ Details

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

- Definition

Amount of liabilities assumed at the acquisition date.

+ References

+ Details

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

- Definition

Amount of liabilities due after one year or the normal operating cycle, if longer, assumed at the acquisition date.

+ References

+ Details

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

- Definition

Amount recognized for assets, including goodwill, in excess of (less than) the aggregate liabilities assumed.

+ References

+ Details

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

- 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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=64834752&loc=SL49117168-202975

+ Details

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

- Details

Name:	us-gaap_BusinessAcquisitionAxis=ibm_AcquisitionsCompletedIn2015Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_DevelopedTechnologyRightsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_CustomerRelationshipsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=ibm_PatentsAndTrademarksMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=ibm_MergeHealthcareIncorporatedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=ibm_CleversafeIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=ibm_SeriesOfIndividuallyImmaterialBusinessAcquisitions2015Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

ACQUISITIONS/DIVESTITURES - 2015 Purchase Price Allocation (Details) - USD ($) $ in Millions			12 Months Ended
	Nov. 06, 2015	Oct. 13, 2015	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2014
ACQUISITIONS
Goodwill			$ 32,021	$ 36,199	$ 30,556
2015 Acquisitions \| Completed technology \| Minimum
ACQUISITIONS
Acquired intangible asset, weighted average useful life			5 years
2015 Acquisitions \| Completed technology \| Maximum
ACQUISITIONS
Acquired intangible asset, weighted average useful life			7 years
2015 Acquisitions \| Client relationships \| Minimum
ACQUISITIONS
Acquired intangible asset, weighted average useful life			5 years
2015 Acquisitions \| Client relationships \| Maximum
ACQUISITIONS
Acquired intangible asset, weighted average useful life			7 years
2015 Acquisitions \| Patents/trademarks \| Minimum
ACQUISITIONS
Acquired intangible asset, weighted average useful life			2 years
2015 Acquisitions \| Patents/trademarks \| Maximum
ACQUISITIONS
Acquired intangible asset, weighted average useful life			7 years
Merge
ACQUISITIONS
Current assets		$ 94
Fixed assets/noncurrent assets		128
Goodwill		695
Total assets acquired		1,248
Current liabilities		(73)
Noncurrent liabilities		(139)
Total liabilities assumed		(212)
Total purchase price		$ 1,036
Acquired intangible asset, weighted average useful life		7 years
Merge \| Completed technology
ACQUISITIONS
Intangible assets		$ 133
Merge \| Client relationships
ACQUISITIONS
Intangible assets		145
Merge \| Patents/trademarks
ACQUISITIONS
Intangible assets		$ 54
Cleversafe
ACQUISITIONS
Current assets	$ 23
Fixed assets/noncurrent assets	63
Goodwill	1,000
Total assets acquired	1,484
Current liabilities	(15)
Noncurrent liabilities	(160)
Total liabilities assumed	(175)
Total purchase price	$ 1,309
Acquired intangible asset, weighted average useful life	6 years 10 months 24 days
Cleversafe \| Completed technology
ACQUISITIONS
Intangible assets	$ 364
Cleversafe \| Client relationships
ACQUISITIONS
Intangible assets	23
Cleversafe \| Patents/trademarks
ACQUISITIONS
Intangible assets	$ 11
Other 2015 Acquisitions
ACQUISITIONS
Current assets			$ 60
Fixed assets/noncurrent assets			82
Goodwill			895
Total assets acquired			1,318
Current liabilities			(34)
Noncurrent liabilities			(73)
Total liabilities assumed			(107)
Total purchase price			$ 1,210
Acquired intangible asset, weighted average useful life			6 years 4 months 24 days
Other 2015 Acquisitions \| Completed technology
ACQUISITIONS
Intangible assets			$ 163
Other 2015 Acquisitions \| Client relationships
ACQUISITIONS
Intangible assets			95
Other 2015 Acquisitions \| Patents/trademarks
ACQUISITIONS
Intangible assets			$ 23