Segment Information (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($) group	Mar. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Net sales	$ 991.2	$ 852.3
Operating Income	$ 99.6	$ 107.8
Operating Income as a % of Net Sales	10.00%	12.60%
Electrical
Segment Reporting Information [Line Items]
Number of business groups (in groups) | group	3
Net sales	$ 618.1	$ 587.5
Operating Income	$ 61.2	$ 52.8
Operating Income as a % of Net Sales	9.90%	9.00%
Power
Segment Reporting Information [Line Items]
Net sales	$ 373.1	$ 264.8
Operating Income	$ 38.4	$ 55.0
Operating Income as a % of Net Sales	10.30%	20.80%