Segment Information (Schedule Of Revenue, Operating Income And Identifiable Assets By Segment) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2021	Oct. 02, 2020	Oct. 01, 2021	Oct. 02, 2020
Segment Reporting Information [Line Items]
Revenue	$ 901.4	$ 792.1	$ 2,733.1	$ 2,318.0
Acquired deferred revenue adjustment	0.0	0.7	0.3	4.0
Segment revenue	901.4	792.8	2,733.4	2,322.0
Amortization of acquired capitalized commissions	(1.1)	(1.3)	(3.4)	(4.2)
Consolidated segment operating income	147.5	102.0	433.2	297.9
Depreciation expense			30.9	29.4
Segment Reconciling
Segment Reporting Information [Line Items]
Consolidated segment operating income	242.5	210.8	731.6	571.8
Operating segment
Segment Reporting Information [Line Items]
Consolidated segment operating income	241.4	210.2	728.5	571.6
Depreciation expense	5.9	5.9	18.0	17.7
Buildings and Infrastructure
Segment Reporting Information [Line Items]
Revenue	349.7	317.4	1,057.4	909.4
Acquired deferred revenue adjustment	0.0	0.0	0.2	0.2
Segment revenue	349.7	317.4	1,057.6	909.6
Amortization of acquired capitalized commissions	(1.0)	(1.3)	(3.2)	(4.0)
Buildings and Infrastructure | Segment Reconciling
Segment Reporting Information [Line Items]
Consolidated segment operating income	101.6	97.2	304.1	245.9
Buildings and Infrastructure | Operating segment
Segment Reporting Information [Line Items]
Consolidated segment operating income	100.6	95.9	301.1	242.1
Depreciation expense	1.7	2.0	5.3	6.1
Geospatial
Segment Reporting Information [Line Items]
Revenue	205.4	165.6	606.8	457.0
Acquired deferred revenue adjustment	0.0	0.0	0.0	0.0
Segment revenue	205.4	165.6	606.8	457.0
Amortization of acquired capitalized commissions	0.0	0.0	0.0	0.0
Geospatial | Segment Reconciling
Segment Reporting Information [Line Items]
Consolidated segment operating income	64.9	51.4	179.7	119.3
Geospatial | Operating segment
Segment Reporting Information [Line Items]
Consolidated segment operating income	64.9	51.4	179.7	119.3
Depreciation expense	1.8	1.5	5.3	4.4
Resources and Utilities
Segment Reporting Information [Line Items]
Revenue	184.8	150.2	587.5	472.1
Acquired deferred revenue adjustment	0.0	0.4	0.0	2.6
Segment revenue	184.8	150.6	587.5	474.7
Amortization of acquired capitalized commissions	0.0	0.0	0.0	(0.1)
Resources and Utilities | Segment Reconciling
Segment Reporting Information [Line Items]
Consolidated segment operating income	60.6	53.9	211.2	167.8
Resources and Utilities | Operating segment
Segment Reporting Information [Line Items]
Consolidated segment operating income	60.6	54.3	211.2	170.3
Depreciation expense	1.4	1.5	4.4	4.1
Transportation
Segment Reporting Information [Line Items]
Revenue	161.5	158.9	481.4	479.5
Acquired deferred revenue adjustment	0.0	0.3	0.1	1.2
Segment revenue	161.5	159.2	481.5	480.7
Amortization of acquired capitalized commissions	(0.1)	0.0	(0.2)	(0.1)
Transportation | Segment Reconciling
Segment Reporting Information [Line Items]
Consolidated segment operating income	15.4	8.3	36.6	38.8
Transportation | Operating segment
Segment Reporting Information [Line Items]
Consolidated segment operating income	15.3	8.6	36.5	39.9
Depreciation expense	$ 1.0	$ 0.9	$ 3.0	$ 3.1