Revenue - Geographic Net Sales Information by Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Net sales	$ 1,269.7	$ 1,183.5
Water
Disaggregation of Revenue [Line Items]
Net sales	732.3	682.9
Water | Operating Segments
Disaggregation of Revenue [Line Items]
Net sales	732.3	682.9
Water | Operating Segments | Aquatic Systems
Disaggregation of Revenue [Line Items]
Net sales	240.4	222.5
Water | Operating Segments | Filtration Solutions
Disaggregation of Revenue [Line Items]
Net sales	251.6	230.8
Water | Operating Segments | Flow Technologies
Disaggregation of Revenue [Line Items]
Net sales	240.3	229.6
Water | Residential
Disaggregation of Revenue [Line Items]
Net sales	412.1	388.3
Water | Commercial
Disaggregation of Revenue [Line Items]
Net sales	151.8	144.7
Water | Industrial
Disaggregation of Revenue [Line Items]
Net sales	168.4	149.9
Water | U.S.
Disaggregation of Revenue [Line Items]
Net sales	452.2	431.2
Water | Western Europe
Disaggregation of Revenue [Line Items]
Net sales	110.3	95.3
Water | Developing
Disaggregation of Revenue [Line Items]
Net sales	113.0	104.9
Water | Other Developed
Disaggregation of Revenue [Line Items]
Net sales	56.8	51.5
Electrical
Disaggregation of Revenue [Line Items]
Net sales	538.9	502.2
Electrical | Operating Segments
Disaggregation of Revenue [Line Items]
Net sales	538.9	502.2
Electrical | Operating Segments | Enclosures
Disaggregation of Revenue [Line Items]
Net sales	254.1	226.5
Electrical | Operating Segments | Thermal Management
Disaggregation of Revenue [Line Items]
Net sales	147.9	145.4
Electrical | Operating Segments | Electrical & Fastening Solutions
Disaggregation of Revenue [Line Items]
Net sales	136.9	130.3
Electrical | Industrial
Disaggregation of Revenue [Line Items]
Net sales	243.5	220.5
Electrical | Commercial & Residential
Disaggregation of Revenue [Line Items]
Net sales	146.0	134.5
Electrical | Energy
Disaggregation of Revenue [Line Items]
Net sales	79.9	88.0
Electrical | Infrastructure
Disaggregation of Revenue [Line Items]
Net sales	69.5	59.2
Electrical | U.S.
Disaggregation of Revenue [Line Items]
Net sales	317.0	300.1
Electrical | Western Europe
Disaggregation of Revenue [Line Items]
Net sales	121.7	103.3
Electrical | Developing
Disaggregation of Revenue [Line Items]
Net sales	56.9	62.1
Electrical | Other Developed
Disaggregation of Revenue [Line Items]
Net sales	43.3	36.7
Other
Disaggregation of Revenue [Line Items]
Net sales	$ (1.5)	$ (1.6)