Goodwill and Other Identifiable Intangible Assets - Changes in Carrying Amount of Goodwill by Segment (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Goodwill [Roll Forward]
Beginning Balance	$ 3,252.6	$ 2,504.5
Acquisitions		790.5
Foreign  currency translation	22.8	(44.8)
Ending Balance	3,274.6	3,252.6
Goodwill, Purchase Accounting Adjustments	(0.8)	2.4
Flow
Goodwill [Roll Forward]
Beginning Balance	747.6	782.0
Acquisitions		0.0
Foreign  currency translation	19.5	(35.4)
Ending Balance	767.1	747.6
Goodwill, Purchase Accounting Adjustments	0.0	1.0
Water Solutions
Goodwill [Roll Forward]
Beginning Balance	1,398.1	618.0
Acquisitions		790.5
Foreign  currency translation	3.3	(9.5)
Ending Balance	1,400.6	1,398.1
Goodwill, Purchase Accounting Adjustments	(0.8)	(0.9)
Pool
Goodwill [Roll Forward]
Beginning Balance	1,106.9	1,104.5
Acquisitions		0.0
Foreign  currency translation	0.0	0.1
Ending Balance	1,106.9	1,106.9
Goodwill, Purchase Accounting Adjustments	$ 0.0	$ 2.3