Restructuring Costs - By Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Pre-tax Restructuring Costs	$ 32.0	$ 12.0	$ 20.3
Cost of goods sold
Restructuring Cost and Reserve [Line Items]
Pre-tax Restructuring Costs	22.3	8.2	13.7
Selling & administrative expense
Restructuring Cost and Reserve [Line Items]
Pre-tax Restructuring Costs	9.7	3.8	6.6
Electrical
Restructuring Cost and Reserve [Line Items]
Pre-tax Restructuring Costs	20.5	8.3	16.9
Electrical | Cost of goods sold
Restructuring Cost and Reserve [Line Items]
Pre-tax Restructuring Costs	12.5	4.9	11.5
Electrical | Selling & administrative expense
Restructuring Cost and Reserve [Line Items]
Pre-tax Restructuring Costs	8.0	3.4	5.4
Power
Restructuring Cost and Reserve [Line Items]
Pre-tax Restructuring Costs	11.5	3.7	3.4
Power | Cost of goods sold
Restructuring Cost and Reserve [Line Items]
Pre-tax Restructuring Costs	9.8	3.3	2.2
Power | Selling & administrative expense
Restructuring Cost and Reserve [Line Items]
Pre-tax Restructuring Costs	$ 1.7	$ 0.4	$ 1.2