Goodwill and Other Intangible Assets Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Roll Forward]
Goodwill, beginning of period	$ 874.7	$ 800.4
Current year acquisitions	55.3	80.9
Foreign currency translation and prior year acquisitions	(1.5)	(6.6)
Goodwill, end of period	928.5	874.7
Electrical
Goodwill [Roll Forward]
Goodwill, beginning of period	568.9	520.9
Current year acquisitions	43.3	53.5
Foreign currency translation and prior year acquisitions	(1.0)	(5.5)
Goodwill, end of period	611.2	568.9
Power
Goodwill [Roll Forward]
Goodwill, beginning of period	305.8	279.5
Current year acquisitions	12.0	27.4
Foreign currency translation and prior year acquisitions	(0.5)	(1.1)
Goodwill, end of period	$ 317.3	$ 305.8