Reporting Segment And Geographic Information (Schedule Of Revenue, Operating Income And Identifiable Assets By Segment) (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 01, 2021	Jan. 03, 2020	Dec. 28, 2018
Segment Reporting Information [Line Items]
Total revenue	$ 3,147.7	$ 3,264.3	$ 3,108.4
Acquired deferred revenue adjustment	4.3	7.0	23.6
Segment revenue	3,152.0	3,271.3	3,132.0
Amortization of acquired capitalized commissions	(5.5)	(6.3)	(4.7)
Operating income	419.8	375.9	320.7
Depreciation expense	39.7	39.4	35.6
Buildings and Infrastructure
Segment Reporting Information [Line Items]
Total revenue	1,230.7	1,254.2	1,065.5
Acquired deferred revenue adjustment	0.3	4.0	22.2
Segment revenue	1,231.0	1,258.2	1,087.7
Amortization of acquired capitalized commissions	(5.2)	(6.2)	(4.5)
Geospatial
Segment Reporting Information [Line Items]
Total revenue	650.5	649.4	723.1
Acquired deferred revenue adjustment	0.0	0.0	0.0
Segment revenue	650.5	649.4	723.1
Amortization of acquired capitalized commissions	0.0	0.0	0.0
Resources and Utilities
Segment Reporting Information [Line Items]
Total revenue	627.3	568.4	567.1
Acquired deferred revenue adjustment	2.7	3.0	1.0
Segment revenue	630.0	571.4	568.1
Amortization of acquired capitalized commissions	(0.1)	(0.1)	(0.2)
Transportation
Segment Reporting Information [Line Items]
Total revenue	639.2	792.3	752.7
Acquired deferred revenue adjustment	1.3	0.0	0.4
Segment revenue	640.5	792.3	753.1
Amortization of acquired capitalized commissions	(0.2)	0.0	0.0
Operating Income
Segment Reporting Information [Line Items]
Operating income	794.8	746.4	715.7
Operating Income | Buildings and Infrastructure
Segment Reporting Information [Line Items]
Operating income	343.0	322.1	239.0
Operating Income | Geospatial
Segment Reporting Information [Line Items]
Operating income	184.4	132.2	166.4
Operating Income | Resources and Utilities
Segment Reporting Information [Line Items]
Operating income	218.4	166.2	167.4
Operating Income | Transportation
Segment Reporting Information [Line Items]
Operating income	49.0	125.9	142.9
Segments Revenue
Segment Reporting Information [Line Items]
Operating income	793.6	747.1	734.6
Depreciation expense	24.0	23.2	21.1
Segments Revenue | Buildings and Infrastructure
Segment Reporting Information [Line Items]
Operating income	338.1	319.9	256.7
Depreciation expense	8.1	8.1	6.4
Segments Revenue | Geospatial
Segment Reporting Information [Line Items]
Operating income	184.4	132.2	166.4
Depreciation expense	6.2	6.3	6.0
Segments Revenue | Resources and Utilities
Segment Reporting Information [Line Items]
Operating income	221.0	169.1	168.2
Depreciation expense	5.6	4.4	4.2
Segments Revenue | Transportation
Segment Reporting Information [Line Items]
Operating income	50.1	125.9	143.3
Depreciation expense	$ 4.1	$ 4.4	$ 4.5