Reporting Segment And Geographic Information (Schedule Of Revenue, Operating Income And Identifiable Assets By Segment) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 29, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016	Sep. 30, 2016	Jul. 01, 2016	Apr. 01, 2016	Dec. 29, 2017		Dec. 30, 2016		Jan. 01, 2016
Segment Reporting Information [Line Items]
Revenues	$ 708.4	$ 670.0	$ 661.9	$ 613.9	$ 585.5	$ 584.1	$ 609.6	$ 583.0	$ 2,654.2	[1]	$ 2,362.2	[1]	$ 2,290.4	[1]
Operating Income (Loss)									246.0		181.0		154.4
Depreciation									34.6		37.0		36.7
Accounts receivable	414.8				354.8				414.8		354.8
Inventories	271.8				218.8				271.8		218.8
Goodwill	2,287.1				2,077.6				2,287.1		2,077.6
Building and Infrastructure [Member]
Segment Reporting Information [Line Items]
Revenues									834.9		743.5		688.6
Accounts receivable	118.5				104.7				118.5		104.7
Inventories	62.1				51.3				62.1		51.3
Goodwill	706.8				663.7				706.8		663.7
Geospatial [Member]
Segment Reporting Information [Line Items]
Revenues									661.2		634.7		672.8
Accounts receivable	117.7				108.3				117.7		108.3
Inventories	110.7				100.4				110.7		100.4
Goodwill	415.3				405.1				415.3		405.1
Resources and Utilities [Member]
Segment Reporting Information [Line Items]
Revenues									476.9		395.7		381.8
Accounts receivable	76.9				65.5				76.9		65.5
Inventories	45.3				31.0				45.3		31.0
Goodwill	314.5				217.7				314.5		217.7
Transportation [Member]
Segment Reporting Information [Line Items]
Revenues									681.2		588.3		547.2
Accounts receivable	101.7				76.3				101.7		76.3
Inventories	53.7				36.1				53.7		36.1
Goodwill	$ 850.5				$ 791.1				850.5		791.1
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)									567.7		476.0		459.9
Operating Segments [Member] | Building and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)									179.9		133.9		108.2
Operating Segments [Member] | Geospatial [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)									130.9		120.8		135.3
Operating Segments [Member] | Resources and Utilities [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)									136.3		118.4		109.9
Operating Segments [Member] | Transportation [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)									120.6		102.9		106.5
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Depreciation									20.0		21.0		21.3
Segment Reconciling Items [Member] | Building and Infrastructure [Member]
Segment Reporting Information [Line Items]
Depreciation									6.2		7.0		7.8
Segment Reconciling Items [Member] | Geospatial [Member]
Segment Reporting Information [Line Items]
Depreciation									5.4		6.5		6.4
Segment Reconciling Items [Member] | Resources and Utilities [Member]
Segment Reporting Information [Line Items]
Depreciation									3.2		2.0		1.9
Segment Reconciling Items [Member] | Transportation [Member]
Segment Reporting Information [Line Items]
Depreciation									$ 5.2		$ 5.5		$ 5.2

[1] Revenue is attributed to countries based on the location of the customer.