Discrete Income Tax Benefit, Share-Based Payment Arrangement

No definition available.

Name:	itw_DiscreteIncomeTaxBenefitShareBasedPaymentArrangement
Namespace Prefix:	itw_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Discrete Income Tax Expense (Benefit)

+ References

No definition available.

+ Details

Name:	itw_DiscreteIncomeTaxExpenseBenefit
Namespace Prefix:	itw_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-12

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 231
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482663/740-10-55-231

+ Details

Name:	us-gaap_EffectiveIncomeTaxRateContinuingOperations
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12A
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-12A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-12

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 231
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482663/740-10-55-231

+ Details

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

- Definition

Estimated amount of loss resulting from an adverse tax position.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-15

+ Details

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

- Details

Name:	us-gaap_TaxPeriodAxis=itw_TaxYears20182021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TaxPeriodAxis=itw_TaxYears20182021IncomeTaxRefundClaimsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TaxPeriodAxis=itw_SubsequentTo2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=us-gaap_ForeignCountryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=us-gaap_DomesticCountryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Income Taxes (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended				9 Months Ended
Income Taxes (Details) - USD ($) $ in Millions	Sep. 30, 2026	Sep. 30, 2026	Mar. 31, 2026	Sep. 30, 2025	Mar. 31, 2025	Sep. 30, 2026	Sep. 30, 2025
Effective Income Tax Rate Reconciliation [Line Items]
Effective income tax rate reconciliation, percent		24.40%		21.80%		23.30%	22.70%
Discrete tax (benefit) expense			$ (34)		$ (21)
Discrete income tax benefits from stock-based compensation		$ 1		$ 2		$ 5	$ 7
Tax Years 2018 -2021
Effective Income Tax Rate Reconciliation [Line Items]
Income tax examination, estimate of possible loss	$ 23
Tax Years 2018 -2021, Income Tax Refund Claims
Effective Income Tax Rate Reconciliation [Line Items]
Income tax examination, estimate of possible loss	47
Subsequent to 2021
Effective Income Tax Rate Reconciliation [Line Items]
Income tax examination, estimate of possible loss	$ 148
Foreign Tax Jurisdiction
Effective Income Tax Rate Reconciliation [Line Items]
Discrete tax (benefit) expense				16			16
Income Tax Jurisdiction, Domestic Federal
Effective Income Tax Rate Reconciliation [Line Items]
Discrete tax (benefit) expense				$ (43)			$ (43)