Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 356.0	$ 407.4	$ 366.1
Other comprehensive income (loss):
Foreign currency translation adjustments	12.3	3.7	(33.9)
Reclassification of currency translation gains included in net income	0.0	(7.7)	0.0
Defined benefit pension and post-retirement plans, net of taxes of $2.9, $5.3 and $(6.3)	(8.8)	(14.5)	17.8
Unrealized gain (loss) on investments, net of taxes of $(0.1), $(0.2) and $0.4	0.4	2.6	(1.4)
Unrealized gains (losses) on cash flow hedges, net of taxes of $0.1, $0.5 and $(0.5)	(0.2)	(1.3)	1.6
Other comprehensive income (loss)	3.7	(17.2)	(15.9)
Comprehensive income	359.7	390.2	350.2
Less: Comprehensive income attributable to noncontrolling interest	4.8	6.5	5.9
COMPREHENSIVE INCOME ATTRIBUTABLE TO HUBBELL	$ 354.9	$ 383.7	$ 344.3