Income 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		6 Months Ended
	Jul. 03, 2015	Jul. 04, 2014	Jul. 03, 2015	Jul. 04, 2014
Income Per Share [Line Items]
Net income attributable to Trimble Navigation Ltd.	$ 25.9	$ 77.9	$ 60.0	$ 146.5
Weighted average number of common shares used in basic income per share	258.4	261.1	258.9	260.4
Effect of dilutive securities	3.0	4.9	3.0	5.0
Weighted average number of common shares and dilutive potential common shares used in diluted income per share	261.4	266.0	261.9	265.4
Basic income per share	$ 0.10	$ 0.30	$ 0.23	$ 0.56
Diluted income per share	$ 0.10	$ 0.29	$ 0.23	$ 0.55