Restructuring Costs and Other - By Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 3.3	$ 4.5	$ 13.5	$ 13.9
Cost of goods sold
Restructuring Cost and Reserve [Line Items]
Restructuring charges	2.2	4.2	9.6	8.3
Selling & administrative expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1.1	0.3	3.9	5.6
Electrical
Restructuring Cost and Reserve [Line Items]
Restructuring charges	2.8	4.3	11.5	12.8
Electrical | Cost of goods sold
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1.9	4.2	8.2	7.8
Electrical | Selling & administrative expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.9	0.1	3.3	5.0
Power
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.5	0.2	2.0	1.1
Power | Cost of goods sold
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.3	0.0	1.4	0.5
Power | Selling & administrative expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 0.2	$ 0.2	$ 0.6	$ 0.6