Earnings Per Share (Schedule Of Computation Of Earnings Per Share And Effect On Weighted-Average Number Of Shares) (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Oct. 02, 2015	Sep. 30, 2016	Oct. 02, 2015
Earnings Per Share Reconciliation [Abstract]
Net income attributable to Trimble Navigation Limited	$ 39.2	$ 37.1	$ 94.7	$ 97.1
Weighted-average shares outstanding	249.7	254.8	250.5	257.5
Effect of dilutive securities	3.5	2.4	3.2	2.8
Weighted-average dilutive shares outstanding	253.2	257.2	253.7	260.3
Basic earnings per share	$ 0.16	$ 0.15	$ 0.38	$ 0.38
Diluted earnings per share	$ 0.15	$ 0.14	$ 0.37	$ 0.37