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. 28, 2018	Dec. 29, 2017		Dec. 30, 2016
Segment Reporting Information [Line Items]
Revenue	$ 785.5		$ 795.2	$ 785.5	$ 742.2	$ 699.8	$ 676.2	$ 659.9	$ 610.6	$ 3,108.4	$ 2,646.5	[1]	$ 2,362.1	[1]
Acquired deferred revenue adjustment										23.6	2.8		2.6
Operating Income (Loss)										320.7	235.7	[1]	180.4	[1]
Amortization of Deferred Sales Commissions										(4.7)	(1.3)		(1.6)
Depreciation										35.6	34.6	[1]	37.0	[1]
Accounts receivable	427.7	[2]				366.2				512.6	427.7	[2]	366.2
Inventories	264.6	[2]				213.3				298.0	264.6	[2]	213.3
Goodwill	2,287.1	[2]				2,077.6				3,540.0	2,287.1	[2]	2,077.6
Building and Infrastructure [Member]
Segment Reporting Information [Line Items]
Revenue										1,065.5	829.4		741.8
Acquired deferred revenue adjustment										22.2	1.1		1.0
Amortization of Deferred Sales Commissions										(4.5)	(0.9)		(1.0)
Accounts receivable	120.1					104.6				177.5	120.1		104.6
Inventories	62.1					51.3				70.3	62.1		51.3
Goodwill	706.8					663.7				1,970.2	706.8		663.7
Geospatial [Member]
Segment Reporting Information [Line Items]
Revenue										723.1	658.5		635.7
Acquired deferred revenue adjustment										0.0	0.0		0.0
Accounts receivable	121.5					109.7				118.7	121.5		109.7
Inventories	110.3					99.2				133.5	110.3		99.2
Goodwill	415.3					405.1				403.1	415.3		405.1
Resources and Utilities [Member]
Segment Reporting Information [Line Items]
Revenue										567.1	481.0		397.4
Acquired deferred revenue adjustment										1.0	1.0		0.8
Amortization of Deferred Sales Commissions										(0.2)	(0.1)		(0.3)
Accounts receivable	78.5					65.6				83.8	78.5		65.6
Inventories	46.0					30.4				46.2	46.0		30.4
Goodwill	314.5					217.7				305.7	314.5		217.7
Transportation [Member]
Segment Reporting Information [Line Items]
Revenue										752.7	677.6		587.2
Acquired deferred revenue adjustment										0.4	0.7		0.8
Amortization of Deferred Sales Commissions											(0.3)		(0.3)
Accounts receivable	107.6					86.3				132.6	107.6		86.3
Inventories	46.2					32.4				48.0	46.2		32.4
Goodwill	$ 850.5					$ 791.1				861.0	850.5		791.1
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue										3,132.0	2,649.3	[3]	2,364.7	[3]
Operating Income (Loss)										734.6	558.3		476.4
Depreciation										21.1	20.0		21.0
Operating Segments [Member] | Building and Infrastructure [Member]
Segment Reporting Information [Line Items]
Revenue										1,087.7	830.5	[3]	742.8	[3]
Operating Income (Loss)										256.7	176.2		132.7
Depreciation										6.4	6.2		7.0
Operating Segments [Member] | Geospatial [Member]
Segment Reporting Information [Line Items]
Revenue										723.1	658.5	[3]	635.7	[3]
Operating Income (Loss)										166.4	129.4		120.6
Depreciation										6.0	5.4		6.5
Operating Segments [Member] | Resources and Utilities [Member]
Segment Reporting Information [Line Items]
Revenue										568.1	482.0	[3]	398.2	[3]
Operating Income (Loss)										168.2	137.9		119.3
Depreciation										4.2	3.2		2.0
Operating Segments [Member] | Transportation [Member]
Segment Reporting Information [Line Items]
Revenue										753.1	678.3	[3]	588.0	[3]
Operating Income (Loss)										143.3	114.8		103.8
Depreciation										4.5	5.2		5.5
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)										715.7	556.8		475.4
Segment Reconciling Items [Member] | Building and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)										239.0	176.0		132.7
Segment Reconciling Items [Member] | Geospatial [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)										166.4	129.4		120.6
Segment Reconciling Items [Member] | Resources and Utilities [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)										167.4	137.0		118.8
Segment Reconciling Items [Member] | Transportation [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)										$ 142.9	$ 114.4		$ 103.3

[1] See Note 2 for a summary of adjustments

[2] See Note 2 for a summary of adjustments

[3] Adjusted to reflect adoption of the new revenue recognition standard, Revenue from Contracts with Customers. For further information, see Note 2.