Restructuring Costs and Other - Summary of Costs (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Total expected costs	$ 38.3
Costs incurred	15.6	$ 12.0
Remaining costs at 9/30/2019	10.7
2019 Restructuring Actions
Restructuring Cost and Reserve [Line Items]
Total expected costs	20.9
Costs incurred	13.8	0.0
Remaining costs at 9/30/2019	7.1
2019 Restructuring Actions | Electrical
Restructuring Cost and Reserve [Line Items]
Total expected costs	15.1
Costs incurred	10.5	0.0
Remaining costs at 9/30/2019	4.6
2019 Restructuring Actions | Power
Restructuring Cost and Reserve [Line Items]
Total expected costs	5.8
Costs incurred	3.3	0.0
Remaining costs at 9/30/2019	2.5
2018 and Prior Restructuring Actions
Restructuring Cost and Reserve [Line Items]
Total expected costs	17.4
Costs incurred	1.8	12.0
Remaining costs at 9/30/2019	3.6
2018 and Prior Restructuring Actions | Electrical
Restructuring Cost and Reserve [Line Items]
Total expected costs	12.7
Costs incurred	0.9	8.3
Remaining costs at 9/30/2019	3.5
2018 and Prior Restructuring Actions | Power
Restructuring Cost and Reserve [Line Items]
Total expected costs	4.7
Costs incurred	0.9	$ 3.7
Remaining costs at 9/30/2019	$ 0.1