Segment Information (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) group	Sep. 30, 2016 USD ($)
Segment Reporting Information [Line Items]
Net sales	$ 950.5	$ 907.4	$ 2,751.1	$ 2,651.0
Operating Income	$ 146.4	$ 136.0	$ 381.1	$ 370.0
Operating Income as a % of Net Sales	15.40%	15.00%	13.90%	14.00%
Electrical
Segment Reporting Information [Line Items]
Number of business groups (in groups) | group			3
Net sales	$ 654.0	$ 634.6	$ 1,897.9	$ 1,858.7
Operating Income	$ 85.6	$ 80.9	$ 206.6	$ 213.5
Operating Income as a % of Net Sales	13.10%	12.70%	10.90%	11.50%
Power
Segment Reporting Information [Line Items]
Net sales	$ 296.5	$ 272.8	$ 853.2	$ 792.3
Operating Income	$ 60.8	$ 55.1	$ 174.5	$ 156.5
Operating Income as a % of Net Sales	20.50%	20.20%	20.50%	19.80%