Segment Information - Reconciliation (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 28, 2020	Jun. 30, 2019	Jun. 28, 2020	Jun. 30, 2019
Net sales:
Net sales	$ 743.3	$ 782.0	$ 1,527.9	$ 1,527.2
Net sales, percentage change	(4.90%)		0.00%
Operating income:
Operating income	$ 109.8	131.9	$ 213.8	229.2
Total segment operating profit, percentage change	(16.80%)		(6.70%)
Corporate, Non-Segment
Operating income:
Operating income	$ (13.8)	(16.3)	$ (29.2)	(34.4)
Total segment operating profit, percentage change	(15.30%)		(15.10%)
Intersegment Eliminations
Net sales:
Net sales	$ 5.5	4.0	$ 12.4	10.4
Instrumentation
Net sales:
Net sales	263.1	264.1	548.2	520.6
Instrumentation | Operating Segments
Net sales:
Net sales	$ 263.1	264.1	$ 548.2	520.6
Net sales, percentage change	(0.40%)		5.30%
Operating income:
Operating income	$ 48.5	49.0	$ 99.3	88.9
Total segment operating profit, percentage change	(1.00%)		11.70%
Digital Imaging
Net sales:
Net sales	$ 237.6	248.4	$ 484.3	480.8
Digital Imaging | Operating Segments
Net sales:
Net sales	$ 237.6	248.4	$ 484.3	480.8
Net sales, percentage change	(4.30%)		0.70%
Operating income:
Operating income	$ 46.8	51.6	$ 90.6	88.2
Total segment operating profit, percentage change	(9.30%)		2.70%
Aerospace and Defense Electronics
Net sales:
Net sales	$ 143.1	176.0	$ 299.4	342.6
Aerospace and Defense Electronics | Operating Segments
Net sales:
Net sales	$ 143.1	176.0	$ 299.4	342.6
Net sales, percentage change	(18.70%)		(12.60%)
Operating income:
Operating income	$ 17.5	38.6	$ 30.9	71.1
Total segment operating profit, percentage change	(54.70%)		(56.50%)
Engineered Systems
Net sales:
Net sales	$ 99.5	93.5	$ 196.0	183.2
Engineered Systems | Operating Segments
Net sales:
Net sales	$ 99.5	93.5	$ 196.0	183.2
Net sales, percentage change	6.40%		7.00%
Operating income:
Operating income	$ 10.8	$ 9.0	$ 22.2	$ 15.4
Total segment operating profit, percentage change	20.00%		44.20%