Goodwill and Other Intangible Assets - Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Goodwill, beginning of period	$ 1,784.4	$ 1,089.0
Current year acquisitions	29.4	708.7
Dispositions	(3.1)
Foreign currency translation and prior year acquisitions	1.1	(13.3)
Goodwill, end of period	1,811.8	1,784.4
Electrical
Goodwill [Roll Forward]
Goodwill, beginning of period	714.1	717.6
Current year acquisitions	15.2	0.0
Dispositions	(3.1)
Foreign currency translation and prior year acquisitions	1.5	(3.5)
Goodwill, end of period	727.7	714.1
Power
Goodwill [Roll Forward]
Goodwill, beginning of period	1,070.3	371.4
Current year acquisitions	14.2	708.7
Dispositions	0.0
Foreign currency translation and prior year acquisitions	(0.4)	(9.8)
Goodwill, end of period	$ 1,084.1	$ 1,070.3