Restructuring Costs and Other - Summary of Costs (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Total expected costs	$ 53.3			$ 53.3
Costs incurred				10.2		$ 35.0
Remaining costs at 6/30/2017	8.1			8.1
Restructuring charges	4.8		$ 3.7	10.2	$ 9.5
Electrical
Restructuring Cost and Reserve [Line Items]
Restructuring charges	3.9		3.4	8.6	8.9
Power
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.9		$ 0.3	1.6	$ 0.6
2017 Restructuring Actions
Restructuring Cost and Reserve [Line Items]
Total expected costs	9.9			9.9
Costs incurred				6.5		0.0
Remaining costs at 6/30/2017	3.4			3.4
Restructuring charges				6.5
2017 Restructuring Actions | Electrical
Restructuring Cost and Reserve [Line Items]
Total expected costs	6.3			6.3
Costs incurred				4.9		0.0
Remaining costs at 6/30/2017	1.4			1.4
2017 Restructuring Actions | Power
Restructuring Cost and Reserve [Line Items]
Total expected costs	3.6			3.6
Costs incurred				1.6		0.0
Remaining costs at 6/30/2017	2.0			2.0
2016 and Prior Restructuring Actions
Restructuring Cost and Reserve [Line Items]
Total expected costs	43.4			43.4
Costs incurred				3.7		35.0
Remaining costs at 6/30/2017	4.7			4.7
Restructuring charges				3.7
2016 and Prior Restructuring Actions | Electrical
Restructuring Cost and Reserve [Line Items]
Total expected costs	41.7			41.7
Costs incurred				3.7		33.9
Remaining costs at 6/30/2017	4.1			4.1
2016 and Prior Restructuring Actions | Power
Restructuring Cost and Reserve [Line Items]
Total expected costs	1.7			1.7
Costs incurred				0.0		$ 1.1
Remaining costs at 6/30/2017	$ 0.6			$ 0.6
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