Goodwill and Other Identifiable Intangible Assets - Changes in Carrying Amount of Goodwill by Segment (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($)
Goodwill [Roll Forward]
Beginning Balance	$ 4,217.4
Goodwill, Purchase Accounting Adjustments	50.6
Foreign currency translation/other	27.3
Ending Balance	4,295.3
Water Unit [Member]
Goodwill [Roll Forward]
Beginning Balance	1,994.6
Goodwill, Purchase Accounting Adjustments	45.3
Foreign currency translation/other	24.7
Ending Balance	2,064.6
Electrical Unit [Member]
Goodwill [Roll Forward]
Beginning Balance	2,222.8
Goodwill, Purchase Accounting Adjustments	5.3
Foreign currency translation/other	2.6
Ending Balance	$ 2,230.7