Restructuring Costs and Other - By Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 4.8	$ 3.7	$ 10.2	$ 9.5
Cost of goods sold
Restructuring Cost and Reserve [Line Items]
Restructuring charges	3.2	2.2	7.4	4.0
Selling & administrative expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1.6	1.5	2.8	5.5
Electrical
Restructuring Cost and Reserve [Line Items]
Restructuring charges	3.9	3.4	8.6	8.9
Electrical | Cost of goods sold
Restructuring Cost and Reserve [Line Items]
Restructuring charges	2.5	2.0	6.3	3.8
Electrical | Selling & administrative expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1.4	1.4	2.3	5.1
Power
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.9	0.3	1.6	0.6
Power | Cost of goods sold
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.7	0.2	1.1	0.2
Power | Selling & administrative expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 0.2	$ 0.1	$ 0.5	$ 0.4