Goodwill and Other Identifiable Intangible Assets - Changes in Carrying Amount of Goodwill by Segment (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2025 USD ($)
Goodwill [Roll Forward]
Beginning Balance	$ 3,286.6
Acquisitions	166.6
Foreign currency translation/other	75.6
Ending Balance	3,528.8
Flow
Goodwill [Roll Forward]
Beginning Balance	730.4
Acquisitions	166.6
Foreign currency translation/other	62.1
Ending Balance	959.1
Water Solutions
Goodwill [Roll Forward]
Beginning Balance	1,392.7
Acquisitions	0.0
Foreign currency translation/other	13.5
Ending Balance	1,406.2
Pool
Goodwill [Roll Forward]
Beginning Balance	1,163.5
Acquisitions	0.0
Foreign currency translation/other	0.0
Ending Balance	$ 1,163.5