Consolidated Statement of Changes in Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss)	Total Hubbell Shareholders' Equity	Total Hubbell Shareholders' Equity Cumulative Effect, Period of Adoption, Adjustment	Non- controlling interest
Beginning of period at Dec. 31, 2017		$ 0.6	$ 11.0	$ 1,892.4		$ (269.8)	$ 1,634.2		$ 13.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 366.1			360.2			360.2		5.9
Other comprehensive (loss) income	$ (15.9)					(15.9)	(15.9)
Stock-based compensation			24.2				24.2
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201409Member
Acquisition and surrender of common shares			(34.5)	(16.0)			(50.5)
Cash dividends declared				(172.8)			(172.8)
Dividends to noncontrolling interest									(3.9)
Aclara noncontrolling interest									2.6
Directors deferred compensation			0.6				0.6
End of period at Dec. 31, 2018		0.6	1.3	2,064.4	$ 0.6	(285.7)	1,780.6	$ 0.6	18.3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 407.4			400.9			400.9		6.5
Other comprehensive (loss) income	(17.2)					(17.2)	(17.2)
Stock-based compensation			16.4				16.4
Reclassification of stranded tax effects				30.0		(30.0)
Acquisition and surrender of common shares			(18.3)	(28.9)			(47.2)
Cash dividends declared				(187.0)			(187.0)
Dividends to noncontrolling interest									(11.4)
Directors deferred compensation			0.6				0.6
End of period at Dec. 31, 2019	1,960.5	0.6	0.0	2,279.4	$ (1.0)	(332.9)	1,947.1	$ (1.0)	13.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	356.0			351.2			351.2		4.8
Other comprehensive (loss) income	$ 3.7					3.7	3.7
Stock-based compensation			23.9				23.9
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Acquisition and surrender of common shares			(17.8)	(34.1)			(51.9)
Cash dividends declared				(201.8)			(201.8)
Dividends to noncontrolling interest									(2.8)
Directors deferred compensation			(1.2)				(1.2)
End of period at Dec. 31, 2020	$ 2,085.4	$ 0.6	$ 4.9	$ 2,393.7		$ (329.2)	$ 2,070.0		$ 15.4