Restructuring Costs and Other - Summary of Costs (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Total expected costs	$ 51.6
Costs incurred	5.5			$ 35.0
Remaining costs at 3/31/2017	11.1
Restructuring charges	5.5		$ 5.8
Electrical
Restructuring Cost and Reserve [Line Items]
Restructuring charges	4.7		5.5
Power
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.8		$ 0.3
2017 Restructuring Actions
Restructuring Cost and Reserve [Line Items]
Total expected costs	5.7
Costs incurred	2.7			0.0
Remaining costs at 3/31/2017	3.0
Restructuring charges	2.7
2017 Restructuring Actions | Electrical
Restructuring Cost and Reserve [Line Items]
Total expected costs	2.8
Costs incurred	1.9			0.0
Remaining costs at 3/31/2017	0.9
2017 Restructuring Actions | Power
Restructuring Cost and Reserve [Line Items]
Total expected costs	2.9
Costs incurred	0.8			0.0
Remaining costs at 3/31/2017	2.1
2016 and Prior Restructuring Actions
Restructuring Cost and Reserve [Line Items]
Total expected costs	45.9
Costs incurred	2.8			35.0
Remaining costs at 3/31/2017	8.1
Restructuring charges	2.8
2016 and Prior Restructuring Actions | Electrical
Restructuring Cost and Reserve [Line Items]
Total expected costs	44.4
Costs incurred	2.8			33.9
Remaining costs at 3/31/2017	7.7
2016 and Prior Restructuring Actions | Power
Restructuring Cost and Reserve [Line Items]
Total expected costs	1.5
Costs incurred	0.0			$ 1.1
Remaining costs at 3/31/2017	$ 0.4
Withdrawal from Multiemployer Defined Benefit Plan | 2017 Restructuring Actions
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 12.5
Withdrawal from Multiemployer Defined Benefit Plan | 2017 Restructuring Actions | Electrical
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 12.5