Restructuring Costs - Summary of Costs (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Expected Costs	$ 11.8
Costs incurred	2.7	5.5
Remaining costs at March 31, 2015	3.6
Current Year Restructuring Actions
Restructuring Cost and Reserve [Line Items]
Expected Costs	1.7
Costs incurred	1.2	0
Remaining costs at March 31, 2015	0.5
Current Year Restructuring Actions | Electrical
Restructuring Cost and Reserve [Line Items]
Expected Costs	1.0
Costs incurred	0.5	0
Remaining costs at March 31, 2015	0.5
Current Year Restructuring Actions | Power
Restructuring Cost and Reserve [Line Items]
Expected Costs	0.7
Costs incurred	0.7	0
Remaining costs at March 31, 2015	0
Prior Year Restructuring Actions
Restructuring Cost and Reserve [Line Items]
Expected Costs	10.1
Costs incurred	1.5	5.5
Remaining costs at March 31, 2015	3.1
Prior Year Restructuring Actions | Electrical
Restructuring Cost and Reserve [Line Items]
Expected Costs	10.1
Costs incurred	1.5	5.5
Remaining costs at March 31, 2015	3.1
Prior Year Restructuring Actions | Power
Restructuring Cost and Reserve [Line Items]
Expected Costs	0
Costs incurred	0	0
Remaining costs at March 31, 2015	$ 0