Significant Accounting Policies	9 Months Ended
Significant Accounting Policies	Sep. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Significant Accounting Policies	Significant Accounting Policies Financial Statements— The unaudited financial statements included herein have been prepared by Illinois Tool Works Inc. and Subsidiaries (the "Company"). In the opinion of management, the interim financial statements reflect all adjustments of a normal recurring nature necessary for a fair statement of the results for interim periods. Interim results are not necessarily indicative of results for the full year. It is suggested that these financial statements be read in conjunction with the financial statements and notes to financial statements included in the Company's 2024 Annual Report on Form 10-K. Certain reclassifications of prior year data have been made to conform with current year reporting. 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. The LIFO provision for the year ended December 31, 2023 was $6 million of expense and was not material to the Company’s results of operations, financial position or cash flows. Therefore, the Company recorded the pre-tax cumulative effect of this change in accounting method of $117 million as a reduction of Cost of revenue in the first quarter of 2024. Refer to Note 7. Inventories for additional information regarding the Company’s inventory balances. 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.