Goodwill and Other Identifiable Intangible Assets - Changes in Carrying Amount of Goodwill by Segment (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 27, 2015	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Beginning Balance		$ 4,217.4	$ 4,259.0
Acquisitions/ divestitures	$ 43.2	32.6	20.8
Goodwill, Purchase Accounting Adjustments			(30.9)
Foreign currency translation/other		101.1	(31.5)
Ending Balance		4,351.1	4,217.4
Water
Goodwill [Roll Forward]
Beginning Balance		1,994.6	2,003.8
Acquisitions/ divestitures		27.3	20.8
Goodwill, Purchase Accounting Adjustments			0.0
Foreign currency translation/other		91.0	(30.0)
Ending Balance		2,112.9	1,994.6
Electrical
Goodwill [Roll Forward]
Beginning Balance		2,222.8	2,255.2
Acquisitions/ divestitures		5.3	0.0
Goodwill, Purchase Accounting Adjustments			(30.9)
Foreign currency translation/other		10.1	(1.5)
Ending Balance		$ 2,238.2	$ 2,222.8