Fair Value Measurements - Additional Fair Value, Narratives (Details) - USD ($) $ in Millions		Jan. 03, 2020	Dec. 28, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability	[1]	$ 19.9	$ 5.6
Debt Outstanding		1,843.2	1,968.5
Business Combination, Contingent Consideration, Liability, Current		13.7
Business Combination, Contingent Consideration, Liability, Noncurrent		6.2
Fair Value, Recurring [Member] | Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Outstanding		1,900.0	$ 2,000.0
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability		$ 33.7

[1] Contingent consideration liabilities represent arrangements to pay the former owners of certain companies that Trimble acquired. The undiscounted maximum payment under the arrangements is $33.7 million at the end of fiscal 2019. The fair values are estimated using scenario-based methods or option pricing methods based upon estimated future revenue, gross margin, or other milestones. At the end of fiscal 2019, the Company had $13.7 million included in Other current liabilities and $6.2 million included in Other non-current liabilities on the Company's Consolidated Balance Sheets.