Segment Information (Schedule Of Revenue, Operating Income And Identifiable Assets By Segment) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Oct. 01, 2021	Sep. 30, 2022	Oct. 01, 2021
Segment Reporting Information [Line Items]
Segment operating income	$ 122.4	$ 147.5	$ 414.2	$ 433.2
Depreciation expense			30.1	30.9
Operating segment
Segment Reporting Information [Line Items]
Segment revenue	884.9	901.4	2,819.8	2,733.4
Segment operating income	238.4	241.4	745.3	728.5
Depreciation expense	5.0	5.9	16.1	18.0
Buildings and Infrastructure | Operating segment
Segment Reporting Information [Line Items]
Segment revenue	363.6	349.7	1,143.8	1,057.6
Segment operating income	96.7	100.6	318.8	301.1
Depreciation expense	1.4	1.7	4.6	5.3
Geospatial | Operating segment
Segment Reporting Information [Line Items]
Segment revenue	184.2	205.4	585.4	606.8
Segment operating income	61.5	64.9	177.2	179.7
Depreciation expense	1.4	1.8	4.5	5.3
Resources and Utilities | Operating segment
Segment Reporting Information [Line Items]
Segment revenue	191.7	184.8	636.4	587.5
Segment operating income	64.2	60.6	212.3	211.2
Depreciation expense	1.4	1.4	4.3	4.4
Transportation | Operating segment
Segment Reporting Information [Line Items]
Segment revenue	145.4	161.5	454.2	481.5
Segment operating income	16.0	15.3	37.0	36.5
Depreciation expense	$ 0.8	$ 1.0	$ 2.7	$ 3.0