Goodwill and Intangible Assets, net - Changes in Goodwill (Details) $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($)
Goodwill [Roll Forward]
BALANCE DECEMBER 31, 2016	$ 991.0
Current year acquisitions (Note 2 – Business Acquisitions)	4.0
Foreign currency translation and prior year acquisitions	5.5
BALANCE MARCH 31, 2017	1,000.5
Electrical
Goodwill [Roll Forward]
BALANCE DECEMBER 31, 2016	652.0
Current year acquisitions (Note 2 – Business Acquisitions)	0.0
Foreign currency translation and prior year acquisitions	3.7
BALANCE MARCH 31, 2017	655.7
Power
Goodwill [Roll Forward]
BALANCE DECEMBER 31, 2016	339.0
Current year acquisitions (Note 2 – Business Acquisitions)	4.0
Foreign currency translation and prior year acquisitions	1.8
BALANCE MARCH 31, 2017	$ 344.8