Significant Accounting Policies (Policies)	9 Months Ended
Significant Accounting Policies (Policies)	Sep. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Inventories	Inventories are stated at the lower of cost or net realizable value and include material, labor and factory overhead. As of December 31, 2023, the last-in, first-out ("LIFO") method was used to determine the cost of inventories at certain U.S. businesses representing approximately 23% of total inventories, and the first-in, first-out ("FIFO") method, which approximates current cost, was used for all other inventories. During the first quarter of 2024, the Company changed the method used to determine the cost of inventory at certain U.S. businesses from LIFO to the FIFO method, as the Company believes the FIFO method is preferable because it provides a more consistent method for valuing inventory across the Company’s operations, improves comparability with peers, and better reflects the current value of inventories at the balance sheet date.
New Accounting Pronouncements	In November 2023, the Financial Accounting Standards Board (the "FASB") issued authoritative guidance which expands annual and interim disclosure requirements for reportable segments. The more significant provisions of this new guidance include the requirement to disclose significant segment expenses and certain disclosures made annually under existing guidance are required for interim periods. The Company adopted this new guidance beginning with its annual reporting for the year ended December 31, 2024 and applied the new disclosure requirements retrospectively to all periods presented. The new guidance did not have an impact on the Company’s results of operations, financial position or cash flows for any period. Refer to Note 12. Segment Information for additional information. In December 2023, the FASB issued authoritative guidance that expands the disclosure requirements for income taxes. The new guidance will require consistent categories and greater disaggregation of information presented in the effective tax rate reconciliation as well as disaggregation of income taxes paid by jurisdiction. The guidance is effective for the Company beginning with its annual reporting for the year ending December 31, 2025 and is required to be applied prospectively, with retrospective application to prior periods allowed. The Company is currently assessing the impact the guidance will have on its disclosures. In November 2024, the FASB issued authoritative guidance which expands annual and interim disclosure requirements related to certain costs and expenses recorded in the income statement. The primary provisions of this new guidance require companies to provide additional footnote disclosures disaggregating income statement line items that include purchases of inventory, employee compensation, depreciation, and intangible asset amortization. The guidance will be effective for the Company beginning with its annual reporting for the year ending December 31, 2027 and is required to be applied prospectively, with retrospective application to prior periods allowed. The Company is currently assessing the impact the guidance will have on its disclosures.
Operating Revenue	Automotive OEM— This segment is a global, niche supplier to top tier OEMs, providing unique innovation to address pain points for sophisticated customers with complex problems. Businesses in this segment produce components and fasteners for automotive-related applications. This segment primarily serves the automotive original equipment manufacturers and tiers market. Products in this segment include: •plastic and metal components, fasteners and assemblies for automobiles, light trucks and other industrial uses. Products sold in this segment are primarily manufactured to the customer's specifications and are sold under long-term supply agreements with OEM auto manufacturers and other top tier auto parts suppliers. The Company typically recognizes revenue for products in this segment at the time of shipment. Certain products may be produced utilizing tooling that is owned by the customer that the Company developed and is reimbursed by the customer for the associated cost. In these arrangements, the Company typically retains a contractual right to use the customer-owned tooling for the purpose of fulfilling its obligations under the supply agreement. The Company records reimbursements for the cost of customer-owned tooling as a cost offset rather than operating revenue as tooling is not considered a product offering central to the Company's operations. Food Equipment— This segment is a highly focused and branded industry leader in commercial food equipment differentiated by innovation and integrated service offerings. This segment primarily serves the food service, food retail and food institutional/restaurant markets. Products in this segment include: •warewashing equipment; •cooking equipment, including ovens, ranges and broilers; •refrigeration equipment, including refrigerators, freezers and prep tables; •food processing equipment, including slicers, mixers and scales; •kitchen exhaust, ventilation and pollution control systems; and •food equipment service, maintenance and repair. Revenue for equipment sold in this segment is typically recognized at the time of product shipment. In limited circumstances involving installation of equipment and customer acceptance, the Company may recognize revenue upon completion of installation and acceptance by the customer. Annual service contracts are typically sold separate from equipment and the related revenue is recognized on a straight-line basis over the annual service period. Operating revenue for on-demand service repairs and parts is recorded upon completion and customer acceptance of the work performed. Test & Measurement and Electronics— This segment is a branded and innovative producer of test and measurement and electronic manufacturing and maintenance, repair, and operations, or "MRO" solutions that improve efficiency and quality for customers in diverse end markets. Businesses in this segment produce equipment, consumables, and related software for testing and measuring of materials and structures, as well as equipment and consumables used in the production of electronic subassemblies and microelectronics. This segment primarily serves the electronics, general industrial, automotive original equipment manufacturers and tiers, energy, industrial capital goods and consumer durables markets. Products in this segment include: •equipment, consumables, and related software for testing and measuring of materials, structures, gases and fluids; •electronic assembly equipment; •electronic components and component packaging; •static control equipment and consumables used for contamination control in clean room environments; and •pressure sensitive adhesives and components for electronics, medical, transportation and telecommunications applications. Revenue for products sold in this segment is typically recognized at the time of shipment. In limited circumstances where significant obligations to the customer are unfulfilled at the time of shipment, typically involving installation of equipment and customer acceptance, revenue recognition is deferred until such obligations have been completed. In other limited arrangements involving the sale of highly specialized systems that include a high degree of customization and installation at the customer site, revenue is recognized over time if the product does not have an alternative use and the Company has an enforceable right to payment for work performed to date. Revenue for transactions meeting these criteria is recognized over time as work is performed based on the costs incurred to date relative to the total estimated costs at completion. Welding— This segment is a branded value-added equipment and specialty consumable manufacturer with innovative and leading technology. Businesses in this segment produce arc welding equipment, consumables and accessories for a wide array of industrial and commercial applications. This segment primarily serves the general industrial market, which includes fabrication, shipbuilding and other general industrial markets, and construction, energy, MRO, industrial capital goods and automotive original equipment manufacturers and tiers markets. Products in this segment include: •arc welding equipment; and •metal arc welding consumables and related accessories. Products in this segment are primarily manufactured to meet anticipated customer demand. The Company typically recognizes revenue for these products at the time of product shipment. Polymers & Fluids— This segment is a branded supplier to niche markets that require value-added, differentiated products. Businesses in this segment produce engineered adhesives, sealants, lubrication and cutting fluids, and fluids and polymers for auto aftermarket maintenance and appearance. This segment primarily serves the automotive aftermarket, general industrial and MRO markets. Products in this segment include: •adhesives for industrial, construction and consumer purposes; •chemical fluids which clean or add lubrication to machines; •epoxy and resin-based coating products for industrial applications; •hand wipes and cleaners for industrial applications; •fluids, polymers and other supplies for auto aftermarket maintenance and appearance; •fillers and putties for auto body repair; and •polyester coatings and patch and repair products for the marine industry. Products in this segment are primarily manufactured to meet anticipated customer demand. The Company typically recognizes revenue for these products at the time of product shipment. Construction Products— This segment is a branded supplier of innovative engineered fastening systems and solutions. This segment primarily serves the residential construction, renovation/remodel and commercial construction markets. Products in this segment include: •fasteners and related fastening tools for wood and metal applications; •anchors, fasteners and related tools for concrete applications; •metal plate truss components and related equipment and software; and •packaged hardware, fasteners, anchors and other products for retail. Products in this segment are primarily manufactured to meet anticipated customer demand. The Company typically recognizes revenue for these products at the time of product shipment. Specialty Products— This segment is focused on diversified niche market opportunities with substantial patent protection producing beverage packaging equipment and consumables, product coding and marking equipment and consumables, and appliance components and fasteners. This segment primarily serves the food and beverage, consumer durables, general industrial, airlines, industrial capital goods and printing and publishing markets. Products in this segment include: •conveyor systems and line automation for the food and beverage industries; •plastic consumables that multi-pack cans and bottles and related equipment; •foil, film and related equipment used to decorate consumer products; •product coding and marking equipment and related consumables; •plastic and metal closures and components for appliances; •airport ground support equipment; and •components for medical devices. Products in this segment are primarily manufactured to meet anticipated customer demand. The Company typically recognizes revenue for these products at the time of product shipment. In limited circumstances where significant obligations to the customer are unfulfilled at the time of shipment, typically involving installation of equipment and customer acceptance, revenue is recognized when such obligations have been completed.
Segment Information	The Company's operations are organized and managed based on similar product offerings and end markets, and are reported to senior management as the following seven segments: Automotive OEM; Food Equipment; Test & Measurement and Electronics; Welding; Polymers & Fluids; Construction Products; and Specialty Products. The following is a description of the Company's seven segments: Automotive OEM— This segment is a global, niche supplier to top tier OEMs, providing unique innovation to address pain points for sophisticated customers with complex problems. Businesses in this segment produce components and fasteners for automotive-related applications. Food Equipment— This segment is a highly focused and branded industry leader in commercial food equipment differentiated by innovation and integrated service offerings. Test & Measurement and Electronics— This segment is a branded and innovative producer of test and measurement and electronic manufacturing and MRO solutions that improve efficiency and quality for customers in diverse end markets. Businesses in this segment produce equipment, consumables, and related software for testing and measuring of materials and structures, as well as equipment and consumables used in the production of electronic subassemblies and microelectronics. Welding— This segment is a branded value-added equipment and specialty consumable manufacturer with innovative and leading technology. Businesses in this segment produce arc welding equipment, consumables and accessories for a wide array of industrial and commercial applications. Polymers & Fluids— This segment is a branded supplier to niche markets that require value-added, differentiated products. Businesses in this segment produce engineered adhesives, sealants, lubrication and cutting fluids, and fluids and polymers for auto aftermarket maintenance and appearance. Construction Products— This segment is a branded supplier of innovative engineered fastening systems and solutions. Specialty Products— This segment is focused on diversified niche market opportunities with substantial patent protection producing beverage packaging equipment and consumables, product coding and marking equipment and consumables, and appliance components and fasteners. The Company’s chief operating decision maker (“CODM”) is the President & Chief Executive Officer. The CODM primarily uses operating income and related operating margins in assessing the current and expected long-term performance of the Company’s segments, including the application of the Company’s enterprise strategies which focus on profitable growth and continuous improvement to margins and returns through the application of the Company’s business model. Operating income and margins are also used by the CODM when evaluating segment investments in capital projects and restructuring initiatives. The CODM regularly reviews summarized financial information related to segment operating revenue, variable margins, overhead expenses, operating income and operating margins as compared to forecasted results. Intersegment sales transactions are accounted for at prices consistent with sales to third parties and are not considered material. Segments are allocated a fixed overhead charge for general corporate administrative expenses based on a percentage of the segment's operating revenue. Expenses not allocated to the segments are reported separately as Unallocated. Because the Unallocated category includes a variety of items, it is subject to fluctuations on a quarterly and annual basis.

Disclosure of inventory accounting policy for inventory classes, including, but not limited to, basis for determining inventory amounts, methods by which amounts are added and removed from inventory classes, loss recognition on impairment of inventories, and situations in which inventories are stated above cost.

- Definition

Disclosure of accounting policy for revenue from contract with customer.

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ILLINOIS TOOL WORKS INC 10-Q