Condensed Consolidated Statements of Changes in Equity - USD ($) shares in Millions, $ in Millions	Total	Ordinary shares	Additional paid-in capital	Retained earnings	Accumulated other comprehensive loss
Beginning Balance at Dec. 31, 2016	$ 4,254.4	$ 1.8	$ 2,920.8	$ 2,068.1	$ (736.3)
Beginning Balance (in shares) at Dec. 31, 2016		181.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	476.9			476.9
Other comprehensive income, net of tax	500.5				500.5
Dividends declared	(189.7)			(189.7)
Share repurchase	(100.0)		(100.0)
Share repurchase (in shares)		(1.5)
Exercise of options, net of shares tendered for payment	41.6		41.6
Exercise of options, net of shares tendered for payment (in shares)		1.1
Issuance of restricted shares, net of cancellations (in shares)		0.3
Issuance of restricted shares, net of cancellations	0.0	$ 0.0
Shares surrendered by employees to pay taxes	(7.3)		(7.3)
Shares surrendered by employees to pay taxes (in shares)		(0.1)
Share-based compensation	32.2		32.2
Ending Balance (in shares) at Sep. 30, 2017		181.6
Ending Balance at Sep. 30, 2017	5,008.6	$ 1.8	2,887.3	2,355.3	(235.8)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of accounting changes	(214.0)			(214.0)
Beginning Balance at Dec. 31, 2017	5,037.8	$ 1.8	2,797.7	2,481.7	(243.4)
Beginning Balance (in shares) at Dec. 31, 2017		180.3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	254.5
Other comprehensive income, net of tax	70.3				70.3
Distributions to nVent	(2,776.8)		(438.2)	(2,290.7)	(47.9)
Dividends declared	(124.0)			(124.0)
Share repurchase	(400.0)		(400.0)
Share repurchase (in shares)		(7.8)
Exercise of options, net of shares tendered for payment	22.8		22.8
Exercise of options, net of shares tendered for payment (in shares)		0.8
Issuance of restricted shares, net of cancellations (in shares)		0.3
Issuance of restricted shares, net of cancellations	0.0	$ 0.0
Shares surrendered by employees to pay taxes	(6.8)		(6.8)
Shares surrendered by employees to pay taxes (in shares)		0.0
Share-based compensation	16.4		16.4
Ending Balance (in shares) at Sep. 30, 2018		173.6
Ending Balance at Sep. 30, 2018	$ 1,880.2	$ 1.8	$ 1,991.9	$ 107.5	$ (221.0)