Segment Information (Schedule Of Revenue, Operating Income And Identifiable Assets By Segment) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jul. 03, 2020	Jun. 28, 2019	Jul. 03, 2020	Jun. 28, 2019
Segment Reporting Information [Line Items]
Revenue	$ 733.6	$ 854.8	$ 1,525.9	$ 1,656.4
Acquired deferred revenue adjustment	1.6	1.0	3.3	3.9
Segment Revenues	735.2	855.8	1,529.2	1,660.3
Amortization of acquired capitalized commissions	(1.4)	(1.6)	(2.9)	(3.3)
Consolidated segment operating income	97.6	109.7	195.9	196.0
Depreciation expense			19.5	20.3
Segment Reconciling
Segment Reporting Information [Line Items]
Consolidated segment operating income	186.1	194.7	361.0	367.7
Operating segment
Segment Reporting Information [Line Items]
Consolidated segment operating income	186.3	194.1	361.4	368.3
Depreciation expense	5.9	6.0	11.8	11.9
Buildings and Infrastructure
Segment Reporting Information [Line Items]
Revenue	295.2	339.0	592.0	631.0
Acquired deferred revenue adjustment	0.1	0.9	0.2	3.6
Segment Revenues	295.3	339.9	592.2	634.6
Amortization of acquired capitalized commissions	(1.3)	(1.6)	(2.7)	(3.2)
Buildings and Infrastructure \| Segment Reconciling
Segment Reporting Information [Line Items]
Consolidated segment operating income	86.6	85.3	148.7	146.7
Buildings and Infrastructure \| Operating segment
Segment Reporting Information [Line Items]
Consolidated segment operating income	85.4	84.6	146.2	147.1
Depreciation expense	2.0	2.1	4.1	4.2
Geospatial
Segment Reporting Information [Line Items]
Revenue	145.2	164.4	291.4	325.6
Acquired deferred revenue adjustment	0.0	0.0	0.0	0.0
Segment Revenues	145.2	164.4	291.4	325.6
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	37.4	31.1	67.9	60.5
Geospatial \| Operating segment
Segment Reporting Information [Line Items]
Consolidated segment operating income	37.4	31.1	67.9	60.5
Depreciation expense	1.5	1.6	2.9	3.2
Resources and Utilities
Segment Reporting Information [Line Items]
Revenue	142.9	152.6	321.9	311.9
Acquired deferred revenue adjustment	0.9	0.1	2.2	0.3
Segment Revenues	143.8	152.7	324.1	312.2
Amortization of acquired capitalized commissions	(0.1)	0.0	(0.1)	(0.1)
Resources and Utilities \| Segment Reconciling
Segment Reporting Information [Line Items]
Consolidated segment operating income	48.3	45.4	113.9	96.4
Resources and Utilities \| Operating segment
Segment Reporting Information [Line Items]
Consolidated segment operating income	49.1	45.5	116.0	96.6
Depreciation expense	1.3	1.1	2.6	2.2
Transportation
Segment Reporting Information [Line Items]
Revenue	150.3	198.8	320.6	387.9
Acquired deferred revenue adjustment	0.6	0.0	0.9	0.0
Segment Revenues	150.9	198.8	321.5	387.9
Amortization of acquired capitalized commissions	0.0	0.0	(0.1)	0.0
Transportation \| Segment Reconciling
Segment Reporting Information [Line Items]
Consolidated segment operating income	13.8	32.9	30.5	64.1
Transportation \| Operating segment
Segment Reporting Information [Line Items]
Consolidated segment operating income	14.4	32.9	31.3	64.1
Depreciation expense	$ 1.1	$ 1.2	$ 2.2	$ 2.3

The amount of expense recognized in the current period for the periodic realization of capitalized fees that were paid to salespeople, distributors, brokers, and agents at the time of the conclusion of the sale. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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