Segment Information - Identifiable Assets (Details) - USD ($) $ in Millions	Jun. 28, 2020	Dec. 29, 2019
Segment Reporting Information [Line Items]
Identifiable assets	$ 4,738.2	$ 4,579.8
Operating Segments | Instrumentation
Segment Reporting Information [Line Items]
Identifiable assets	1,693.0	1,680.2
Operating Segments | Digital Imaging
Segment Reporting Information [Line Items]
Identifiable assets	1,888.7	1,874.6
Operating Segments | Aerospace and Defense Electronics
Segment Reporting Information [Line Items]
Identifiable assets	590.2	618.3
Operating Segments | Engineered Systems
Segment Reporting Information [Line Items]
Identifiable assets	154.4	143.4
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Identifiable assets	$ 411.9	$ 263.3