UPDATES TO SIGNIFICANT ACCOUNTING POLICIES Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 29, 2017
Accounting Policies [Abstract]
Reclassification Policy, Reportable Segments	Reportable Segments In March 2017, the Company effected a change in the reporting of its segment financial results to better reflect the Company's customer base and end markets. Beginning with the first quarter of fiscal 2017, the Company reports its financial performance, including revenues and operating income, based on four new reportable segments: Buildings and Infrastructure, Geospatial, Resources and Utilities, and Transportation. Comparative period financial information by reportable segment has been recast to conform with the current presentation. See Note 6 of the Notes to Condensed Consolidated Financial Statements for further information.
Use of Estimates, Policy	Use of Estimates The preparation of financial statements in accordance with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in its Condensed Consolidated Financial Statements and accompanying notes. Estimates are used for allowances for doubtful accounts, sales returns reserve, allowances for inventory valuation, warranty costs, investments, goodwill impairment, intangibles impairment, purchased intangibles, stock-based compensation, and income taxes among others. Management bases its estimates on historical experience and various other assumptions believed to be reasonable. Although these estimates are based on management’s best knowledge of current events and actions that may impact the Company in the future, actual results may be different from the estimates.
Revenue Recognition, Policy	The Company has presented revenue and cost of sales separately for products, service, and subscriptions. Product revenue includes hardware, software licenses, parts and accessories; service revenue includes maintenance and support for hardware and software products, training, and professional services; subscription revenue includes software as a service ("SaaS").
New Accounting Pronouncements, Policy	Recent Accounting Pronouncements In May 2014, the FASB issued a comprehensive new revenue recognition standard that replaces the current revenue recognition guidance under U.S. GAAP. The new standard requires companies to recognize revenue in a way that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The new standard may be applied either retrospectively to each prior period presented or with the cumulative effect recognized as of the date of initial application. The Company plans to adopt this accounting standard update in the first quarter of fiscal 2018 using the full retrospective adoption method. The Company does not anticipate that its internal control framework will materially change, but rather existing internal controls will be modified and augmented as necessary to implement the new revenue standard. The new standard may impact, in some cases, the timing and amount of revenue recognized. Additionally, direct costs to obtain and fulfill customer contracts, in some cases, may be deferred and amortized under the new standard. The Company is currently evaluating the qualitative and quantitative impacts on the financial statements and related disclosures. In January 2016, the FASB issued final guidance that will require entities to measure equity investments that do not result in consolidation and are not accounted for under the equity method at fair value and recognize any changes in fair value in net income unless the investments qualify for the new practicability exception. The amendments are effective for the Company beginning in fiscal 2018, although early adoption is permitted and should be applied by means of a cumulative-effect adjustment to the balance sheet as of the beginning of the fiscal year of adoption, with certain exceptions. The Company is currently evaluating the effect of the updated standard on its consolidated financial statements and related disclosures. In February 2016, the FASB issued new guidance that requires a lessee to recognize assets and liabilities arising from leases on the balance sheet. Current GAAP does not require lease assets and liabilities to be recognized for most leases. Additionally, companies are permitted to make an accounting policy election to not recognize lease assets and liabilities for leases with a term of 12 months or less. For both finance leases and operating leases, the lease liability should be initially measured at the present value of the lease payments. This new guidance is effective for the Company beginning in fiscal 2019, although early adoption is permitted. The Company is currently evaluating the effect of this guidance on its consolidated financial statements and related disclosures. In June 2016, the FASB issued new guidance that requires credit losses on financial assets measured at amortized cost basis to be presented based on the net amount expected to be collected, not based on incurred losses. Further, credit losses on available-for-sale debt securities should be recorded through an allowance for credit losses limited to the amount by which fair value is below amortized cost. The new standard is effective for the Company beginning in fiscal 2020. Early adoption for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018 is permitted. The Company is currently evaluating the effect of the updated standard on its consolidated financial statements and related disclosures. In August 2016, the FASB issued new guidance related to the statement of cash flows. This guidance amended the existing accounting standards for the statement of cash flows and provided guidance on certain classification issues related to the statement of cash flows. The new standard is effective for the Company beginning in fiscal 2018 and early adoption is permitted. The amendments should be applied retrospectively to all periods presented. For issues that are impracticable to apply retrospectively, the amendments may be applied prospectively as of the earliest date practicable. The Company is currently evaluating the effect of these amendments on its statement of cash flows, which will likely include a reclassification of contingent consideration payments for business combinations from cash flows from investing activities, to both cash flows from operating and financing activities. In October 2016, the FASB issued new guidance related to income taxes. This standard requires the recognition of the income tax consequences of an intra-entity transfer of an asset, other than inventory, when the transfer occurs. The guidance will be effective for the Company in its first quarter of fiscal 2018. The Company is currently evaluating the effect of the updated standard on its consolidated financial statements and related disclosures. In January 2017, the FASB issued new guidance that simplifies the accounting for goodwill impairment by requiring impairment charges to be based on the first step in current GAAP's two-step impairment test. The impairment test is performed by comparing the fair value of a reporting unit with its carrying amount and an impairment charge would be recognized for the amount by which the carrying amount exceeds the reporting unit’s fair value. The new standard is to be applied on a prospective basis and is effective for the Company beginning in fiscal 2020 and early adoption is permitted. The Company is currently evaluating the effect of the updated standard on its consolidated financial statements and related disclosures. In February 2017, the FASB issued new guidance clarifying the scope and application of existing guidance related to the sale or transfer of non-financial assets to non-customers, including partial sales. The amendments are effective at the same time as the new revenue recognition guidance, which the Company expects to adopt in the first quarter of fiscal 2018. The Company is currently evaluating the effect of the updated standard on its consolidated financial statements and related disclosures.
Share-based Compensation Policy	Stock compensation expense is recognized based on the fair value of the portion of share-based payment awards that is expected to vest during the period and is net of estimated forfeitures.
Business Combinations Policy	The Company determined the total consideration paid for each of its acquisitions as well as the fair value of the assets acquired and liabilities assumed as of the date of acquisition. For certain acquisitions completed in the last quarter of fiscal 2016 and the first three quarters of fiscal 2017, the fair value of the assets acquired and liabilities assumed are preliminary and may be adjusted as the Company obtains additional information, primarily related to adjustments for the true up of acquired net working capital in accordance with certain purchase agreements, and estimated values of certain net tangible assets and liabilities including tax balances, pending the completion of final studies and analyses. If there are adjustments made for these items, the fair value of intangible assets and goodwill could be impacted. Thus, the provisional measurements of fair value are subject to change. Such changes could be significant. The Company expects to finalize the valuation of the net tangible and intangible assets as soon as practicable, but not later than one-year from the acquisition date. The fair value of identifiable assets acquired and liabilities assumed were determined under the acquisition method of accounting for business combinations. The excess of purchase consideration over the fair value of net tangible and identifiable intangible assets acquired was recorded as goodwill. The fair value of intangible assets acquired is generally determined based on a discounted cash flow analysis. Acquisition costs directly related to the acquisitions, including the changes in the fair value of the contingent consideration liabilities, a net benefit of $0.3 million and a net expense of $6.1 million for the third quarter and the first three quarters of fiscal 2017, respectively, and net expenses of $0.9 million and $3.4 million for the third quarter and the first three quarters of fiscal 2016, respectively, were recorded as incurred and were included in General and administrative expense in the Condensed Consolidated Statements of Income.
Goodwill, Policy	Goodwill In March 2017, the information used to allocate resources and assess performance that is provided to the Company's chief operating decision maker, its Chief Executive Officer, changed to better reflect the Company's customer base and end markets. As further described in Note 6, the new reporting structure consists of four operating segments, each representing a single reporting unit: Buildings and Infrastructure, Geospatial, Resources and Utilities, and Transportation. Goodwill was reassigned to the new reporting units using the relative fair values and, as a result of this reassignment, an impairment assessment was performed immediately before and after the reorganization of the Company’s reporting structure.
Available-for-sale Securities, Policy	The Company’s available-for-sale securities are liquid and may be sold in the future to fund future operating needs. As a result, the Company recorded all of its available-for-sale securities, not classified as Cash equivalents, in Short-term investments regardless of the contractual maturity date of the securities.
Derivatives Asset and Liabilities Policy	Derivative assets and liabilities primarily represent forward currency exchange contracts. The Company typically enters into these contracts to minimize the short-term impact of foreign currency exchange rates on certain trade and inter-company receivables and payables. The fair values are determined using inputs based on observable quoted prices. Derivative assets and liabilities are included in Other current assets and Other current liabilities on the Company's Condensed Consolidated Balance Sheets.
Product Warranties Policy	The Company accrues for warranty costs as part of its cost of sales based on associated material product costs, technical support, labor costs, and costs incurred by third parties performing work on the Company’s behalf. The Company’s expected future costs are primarily estimated based upon historical trends in the volume of product returns within the warranty period and the costs to repair or replace the equipment. When products sold include warranty provisions, they are covered by a warranty for periods ranging generally from 1 year to 2 years. While the Company engages in extensive product quality programs and processes, including actively monitoring and evaluating the quality of component suppliers, its warranty obligation is affected by product failure rates, material usage and service delivery costs incurred in correcting a product failure. Should actual product failure rates, material usage, or service delivery costs differ from the estimates, revisions to the estimated warranty accrual and related costs may be required.
Earnings Per Share, Policy	Basic earnings per share is computed by dividing Net income attributable to Trimble Inc. by the weighted-average number of shares of common stock outstanding during the period. Diluted earnings per share is computed by dividing Net income attributable to Trimble Inc.by the weighted-average number of shares of common stock outstanding during the period increased to include the number of additional shares of common stock that would have been outstanding if the potentially dilutive securities had been issued. Potentially dilutive securities include outstanding stock options, shares to be purchased under the Company’s employee stock purchase plan, restricted stock units and contingently issuable shares. The dilutive effect of potentially dilutive securities is reflected in diluted earnings per share by application of the treasury stock method. Under the treasury stock method, an increase in the fair market value of the Company’s common stock can result in a greater dilutive effect from potentially dilutive securities.
Income Tax, Policy	The Company's practice is to recognize interest and/or penalties related to income tax matters in income tax expense. As of the end of the third quarter of fiscal 2017 and fiscal year end 2016, the Company had accrued $10.6 million and $9.3 million, respectively, for interest and penalties, which are recorded in Other non-current liabilities in the accompanying Condensed Consolidated Balance Sheets.