Supplemental Guarantor Information - Condensed Consolidating Statement of Cash Flows (Detail) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2014
Operating activities
Net cash provided by (used for) operating activities		$ 353.0	$ 439.1	$ 620.2
Investing activities
Capital expenditures		(58.5)	(48.2)	(39.1)
Proceeds from sale of property and equipment		0.6	0.2	3.7
Proceeds from (payments due to) sale of businesses		15.3	(12.8)	2,759.4	$ 2,759.4
Acquisitions, net of cash acquired		(287.8)	(0.9)	(45.9)
Net intercompany loan activity		0.0	0.0	0.0
Payments for (Proceeds from) Other Investing Activities		1.5	0.0	0.0
Net cash (used for) provided by investing activities of continuing operations		(331.9)	(61.7)	2,678.1
Net cash used for investing activities of discontinued operations		0.0	(7.1)	(47.7)
Net cash (used for) provided by investing activities		(331.9)	(68.8)	2,630.4
Financing activities
Net receipts (repayments) of commercial paper and revolving long-term debt		51.5	39.7	(913.1)
Proceeds from long-term debt		600.0	0.0	0.0
Repayment of long-term debt		(401.5)	(675.1)	(2,009.3)
Premium paid on early extinguishment of debt		0.0	(16.0)	(94.9)
Distribution of cash from nVent, net of cash transferred	$ 993.6	0.0	919.4	0.0
Net change in advances to subsidiaries		0.0	0.0	0.0
Distribution of cash from nVent, net of cash transferred			919.4
Shares issued to employees, net of shares withheld		12.5	13.3	37.2
Repurchases of ordinary shares		(150.0)	(500.0)	(200.0)
Dividends paid		(122.7)	(187.2)	(251.7)
Other		(6.9)	(2.0)	(0.8)
Net cash provided by (used for) financing activities of continuing operations		(17.1)	(407.9)	(3,432.6)
Change in cash held for sale		0.0	27.0	(5.4)
Effect of exchange rate changes on cash and cash equivalents		4.2	(1.4)	56.8
Change in cash and cash equivalents		8.2	(12.0)	(130.6)
Cash and cash equivalents, beginning of year		74.3	86.3	216.9
Cash and cash equivalents, end of year		82.5	74.3	86.3
Eliminations
Operating activities
Net cash provided by (used for) operating activities		(1,096.7)	(1,197.6)	(2,185.0)
Investing activities
Capital expenditures		0.0	0.0	0.0
Proceeds from sale of property and equipment		0.0	0.0	0.0
Proceeds from (payments due to) sale of businesses		0.0	0.0	0.0
Acquisitions, net of cash acquired		0.0	0.0	0.0
Net intercompany loan activity		365.8	(1,930.8)	(217.3)
Payments for (Proceeds from) Other Investing Activities		0.0
Net cash (used for) provided by investing activities of continuing operations			(1,930.8)	(217.3)
Net cash used for investing activities of discontinued operations			0.0	0.0
Net cash (used for) provided by investing activities		365.8	(1,930.8)	(217.3)
Financing activities
Net receipts (repayments) of commercial paper and revolving long-term debt		0.0	0.0	0.0
Proceeds from long-term debt		0.0
Repayment of long-term debt		0.0	0.0	0.0
Premium paid on early extinguishment of debt			0.0	0.0
Net change in advances to subsidiaries		730.9	3,128.4	2,402.3
Distribution of cash from nVent, net of cash transferred			0.0
Shares issued to employees, net of shares withheld		0.0	0.0	0.0
Repurchases of ordinary shares		0.0	0.0	0.0
Dividends paid		0.0	0.0	0.0
Other		0.0	0.0	0.0
Net cash provided by (used for) financing activities of continuing operations		730.9	3,128.4	2,402.3
Change in cash held for sale			0.0	0.0
Effect of exchange rate changes on cash and cash equivalents		0.0	0.0	0.0
Change in cash and cash equivalents		0.0	0.0	0.0
Cash and cash equivalents, beginning of year		0.0	0.0	0.0
Cash and cash equivalents, end of year		0.0	0.0	0.0
Parent Company Guarantor
Operating activities
Net cash provided by (used for) operating activities		361.6	266.3	678.3
Investing activities
Capital expenditures		0.0	0.0	0.0
Proceeds from sale of property and equipment		0.0	0.0	0.0
Proceeds from (payments due to) sale of businesses		0.0	0.0	0.0
Acquisitions, net of cash acquired		0.0	0.0	0.0
Net intercompany loan activity		(127.8)	0.0	0.0
Payments for (Proceeds from) Other Investing Activities		0.0
Net cash (used for) provided by investing activities of continuing operations			0.0	0.0
Net cash used for investing activities of discontinued operations			0.0	0.0
Net cash (used for) provided by investing activities		(127.8)	0.0	0.0
Financing activities
Net receipts (repayments) of commercial paper and revolving long-term debt		0.0	0.0	0.0
Proceeds from long-term debt		0.0
Repayment of long-term debt		0.0	0.0	0.0
Premium paid on early extinguishment of debt			0.0	0.0
Net change in advances to subsidiaries		26.3	407.7	(263.8)
Distribution of cash from nVent, net of cash transferred			0.0
Shares issued to employees, net of shares withheld		12.5	13.3	37.2
Repurchases of ordinary shares		(150.0)	(500.0)	(200.0)
Dividends paid		(122.7)	(187.2)	(251.7)
Other		0.0	0.0	0.0
Net cash provided by (used for) financing activities of continuing operations		(233.9)	(266.2)	(678.3)
Change in cash held for sale			0.0	0.0
Effect of exchange rate changes on cash and cash equivalents		0.0	0.0	0.0
Change in cash and cash equivalents		(0.1)	0.1	0.0
Cash and cash equivalents, beginning of year		0.1	0.0	0.0
Cash and cash equivalents, end of year		0.0	0.1	0.0
Subsidiary Guarantor
Operating activities
Net cash provided by (used for) operating activities		367.1	362.1	676.1
Investing activities
Capital expenditures		0.0	0.0	0.0
Proceeds from sale of property and equipment		0.0	0.0	0.0
Proceeds from (payments due to) sale of businesses		0.0	0.0	0.0
Acquisitions, net of cash acquired		0.0	0.0	0.0
Net intercompany loan activity		(131.7)	94.1	(58.9)
Payments for (Proceeds from) Other Investing Activities		0.0
Net cash (used for) provided by investing activities of continuing operations			94.1	(58.9)
Net cash used for investing activities of discontinued operations			0.0	0.0
Net cash (used for) provided by investing activities		(131.7)	94.1	(58.9)
Financing activities
Net receipts (repayments) of commercial paper and revolving long-term debt		0.0	0.0	0.0
Proceeds from long-term debt		0.0
Repayment of long-term debt		0.0	0.0	0.0
Premium paid on early extinguishment of debt			0.0	0.0
Net change in advances to subsidiaries		(235.4)	(456.2)	(617.2)
Distribution of cash from nVent, net of cash transferred			0.0
Shares issued to employees, net of shares withheld		0.0	0.0	0.0
Repurchases of ordinary shares		0.0	0.0	0.0
Dividends paid		0.0	0.0	0.0
Other		0.0	0.0	0.0
Net cash provided by (used for) financing activities of continuing operations		(235.4)	(456.2)	(617.2)
Change in cash held for sale			0.0	0.0
Effect of exchange rate changes on cash and cash equivalents		0.0	0.0	0.0
Change in cash and cash equivalents		0.0	0.0	0.0
Cash and cash equivalents, beginning of year		0.0	0.0	0.0
Cash and cash equivalents, end of year		0.0	0.0	0.0
Subsidiary Issuer
Operating activities
Net cash provided by (used for) operating activities		381.0	370.6	656.2
Investing activities
Capital expenditures		0.0	0.0	0.0
Proceeds from sale of property and equipment		0.0	0.0	0.0
Proceeds from (payments due to) sale of businesses		0.0	0.0	2,765.6
Acquisitions, net of cash acquired		0.0	0.0	0.0
Net intercompany loan activity		(309.9)	181.0	103.7
Payments for (Proceeds from) Other Investing Activities		0.0
Net cash (used for) provided by investing activities of continuing operations			181.0	2,869.3
Net cash used for investing activities of discontinued operations			0.0	0.0
Net cash (used for) provided by investing activities		(309.9)	181.0	2,869.3
Financing activities
Net receipts (repayments) of commercial paper and revolving long-term debt		41.9	41.9	(914.7)
Proceeds from long-term debt		600.0
Repayment of long-term debt		(401.5)	(675.1)	(1,917.8)
Premium paid on early extinguishment of debt			(16.0)	(86.0)
Net change in advances to subsidiaries		(301.0)	(874.6)	(680.8)
Distribution of cash from nVent, net of cash transferred			993.6
Shares issued to employees, net of shares withheld		0.0	0.0	0.0
Repurchases of ordinary shares		0.0	0.0	0.0
Dividends paid		0.0	0.0	0.0
Other		(6.9)	(2.0)	0.0
Net cash provided by (used for) financing activities of continuing operations		(67.5)	(532.2)	(3,599.3)
Change in cash held for sale			0.0	0.0
Effect of exchange rate changes on cash and cash equivalents		(3.6)	(19.3)	73.8
Change in cash and cash equivalents		0.0	0.1	0.0
Cash and cash equivalents, beginning of year		0.1	0.0	0.0
Cash and cash equivalents, end of year		0.1	0.1	0.0
Non-Guarantor Subsidiaries
Operating activities
Net cash provided by (used for) operating activities		340.0	637.7	794.6
Investing activities
Capital expenditures		(58.5)	(48.2)	(39.1)
Proceeds from sale of property and equipment		0.6	0.2	3.7
Proceeds from (payments due to) sale of businesses		15.3	(12.8)	(6.2)
Acquisitions, net of cash acquired		(287.8)	(0.9)	(45.9)
Net intercompany loan activity		203.6	1,655.7	172.5
Payments for (Proceeds from) Other Investing Activities		1.5
Net cash (used for) provided by investing activities of continuing operations			1,594.0	85.0
Net cash used for investing activities of discontinued operations			(7.1)	(47.7)
Net cash (used for) provided by investing activities		(128.3)	1,586.9	37.3
Financing activities
Net receipts (repayments) of commercial paper and revolving long-term debt		9.6	(2.2)	1.6
Proceeds from long-term debt		0.0
Repayment of long-term debt		0.0	0.0	(91.5)
Premium paid on early extinguishment of debt			0.0	(8.9)
Net change in advances to subsidiaries		(220.8)	(2,205.3)	(840.5)
Distribution of cash from nVent, net of cash transferred			(74.2)
Shares issued to employees, net of shares withheld		0.0	0.0	0.0
Repurchases of ordinary shares		0.0	0.0	0.0
Dividends paid		0.0	0.0	0.0
Other		0.0	0.0	(0.8)
Net cash provided by (used for) financing activities of continuing operations		(211.2)	(2,281.7)	(940.1)
Change in cash held for sale			27.0	(5.4)
Effect of exchange rate changes on cash and cash equivalents		7.8	17.9	(17.0)
Change in cash and cash equivalents		8.3	(12.2)	(130.6)
Cash and cash equivalents, beginning of year		74.1	86.3	216.9
Cash and cash equivalents, end of year		$ 82.4	$ 74.1	$ 86.3