Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator:
Net income attributable to Hubbell	$ 113.6	$ 80.8	$ 272.2	$ 222.7
Less: Earnings allocated to participating securities	(0.4)	(0.3)	(1.0)	(0.7)
Net income available to common shareholders	$ 113.2	$ 80.5	$ 271.2	$ 222.0
Denominator:
Average number of common shares outstanding (in shares)	54.6	54.6	54.7	54.9
Potential dilutive common shares (in shares)	0.3	0.3	0.3	0.3
Average number of diluted shares outstanding (in shares)	54.9	54.9	55.0	55.2
Earnings per share:
Basic (USD per share)	$ 2.07	$ 1.47	$ 4.96	$ 4.05
Diluted (USD per share)	$ 2.06	$ 1.47	$ 4.93	$ 4.02