BUSINESS SEGMENTS - Segment Operating Income Results (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 28, 2018	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Dec. 29, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 28, 2018	Dec. 29, 2017	Dec. 30, 2016
Segment Reporting Information [Line Items]
Amortization of intangible assets										$ (37.3)	$ (36.1)	$ (37.6)
Acquisition and integration costs										(2.6)
CEO retirement agreement expense										(18.9)	(18.1)	(16.5)
Impairment of intangible assets										0.0	(5.7)	0.0
Network and Security Solutions [Member]
Segment Reporting Information [Line Items]
Amortization of intangible assets										(17.0)	(14.4)	(14.1)
Electrical and Electronic Solutions [Member]
Segment Reporting Information [Line Items]
Amortization of intangible assets										(7.0)	(8.4)	(8.5)
Utility Power Solutions [Member]
Segment Reporting Information [Line Items]
Amortization of intangible assets										(13.3)	(13.3)	(15.0)
Corporate [Member]
Segment Reporting Information [Line Items]
Amortization of intangible assets	[1]									0.0	0.0	0.0
Operating Income (Loss) [Member]
Segment Reporting Information [Line Items]
Amortization of intangible assets		$ (8.7)	$ (9.6)	$ (9.7)	$ (9.3)	$ (9.0)	$ (9.1)	$ (9.0)	$ (9.0)	(37.3)	(36.1)	(37.6)
Restructuring charges			(0.2)	(9.2)						(9.4)	0.0	(5.4)
Acquisition and integration costs			(0.3)	(2.3)	(0.3)	(1.5)	$ (0.8)			(2.9)	(2.3)	(5.1)
CEO retirement agreement expense										(2.6)
U.K. facility relocation costs			$ 0.2	$ 0.4	$ 0.2					1.0
Impairment of intangible assets						$ (5.7)					(5.7)
UK pension settlement												(9.6)
Latin America bad debt provision												(7.6)
Items impacting operating expense and operating income										(53.2)	(44.1)	(65.3)
Operating Income (Loss) [Member] | Network and Security Solutions [Member]
Segment Reporting Information [Line Items]
Amortization of intangible assets										(17.0)	(14.4)	(14.1)
Restructuring charges										(2.1)	0.0	(1.7)
Acquisition and integration costs										(2.6)	0.0	0.0
CEO retirement agreement expense										0.0
U.K. facility relocation costs										0.2
Impairment of intangible assets											(5.7)
UK pension settlement												0.0
Latin America bad debt provision												(3.9)
Items impacting operating expense and operating income										(21.9)	(20.1)	(19.7)
Operating Income (Loss) [Member] | Electrical and Electronic Solutions [Member]
Segment Reporting Information [Line Items]
Amortization of intangible assets										(7.0)	(8.4)	(8.5)
Restructuring charges										(1.3)	0.5	(1.3)
Acquisition and integration costs										0.0	0.0	0.0
CEO retirement agreement expense										0.0
U.K. facility relocation costs										0.8
Impairment of intangible assets											0.0
UK pension settlement												0.0
Latin America bad debt provision												(3.7)
Items impacting operating expense and operating income										(9.1)	(7.9)	(13.5)
Operating Income (Loss) [Member] | Utility Power Solutions [Member]
Segment Reporting Information [Line Items]
Amortization of intangible assets										(13.3)	(13.3)	(15.0)
Restructuring charges										(0.7)	(0.1)	(2.1)
Acquisition and integration costs										0.0	0.0	(0.3)
CEO retirement agreement expense										0.0
U.K. facility relocation costs										0.0
Impairment of intangible assets											0.0
UK pension settlement												0.0
Latin America bad debt provision												0.0
Items impacting operating expense and operating income										(14.0)	(13.4)	(17.4)
Operating Income (Loss) [Member] | Corporate [Member]
Segment Reporting Information [Line Items]
Amortization of intangible assets										0.0	0.0	0.0
Restructuring charges										(5.3)	(0.4)	(0.3)
Acquisition and integration costs										(0.3)	(2.3)	(4.8)
CEO retirement agreement expense										(2.6)
U.K. facility relocation costs										0.0
Impairment of intangible assets											0.0
UK pension settlement												(9.6)
Latin America bad debt provision												0.0
Items impacting operating expense and operating income										$ (8.2)	$ (2.7)	$ (14.7)

[1] Corporate "Total assets" primarily consists of cash and cash equivalents, deferred tax assets, and corporate fixed assets.