Financial Statements of Parent Company Guarantor - Condensed Consolidating Statement of Cash Flows (Detail) - USD ($) $ in Millions	1 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided by (Used in) Operating Activities, Continuing Operations		$ 177.8	$ 84.9
Transfer of cash to nVent		(74.2)	0.0
Distribution of cash from nVent	$ 993.6	993.6	0.0
Net cash provided by (used for) operating activities of discontinued operations		(5.9)	70.4
Operating activities
Net cash provided by (used for) operating activities		171.9	155.3
Investing activities
Capital expenditures		(20.3)	(18.7)
Proceeds from the sale of property and equipment, net		(0.5)	0.0
(Payments due to) proceeds from the sale of businesses, net		(12.8)	2,765.6
Acquisitions, net of cash acquired		(0.9)	(45.9)
Intercompany Loan Activity, Net		0.0	0.0
Net cash provided by (used for) investing activities of continuing operations		(34.5)	2,701.0
Net cash provided by (used for) investing activities of discontinued operations		(7.1)	(35.2)
Net cash provided by (used for) investing activities		(41.6)	2,665.8
Financing activities
Net receipts of short-term borrowings		0.0	(0.5)
Net receipts (repayments) of commercial paper and revolving long-term debt		30.2	(975.5)
Repayments of Long-term Debt		(675.1)	(1,659.3)
Net change in advances to subsidiaries		0.0	0.0
Shares issued to employees, net of shares withheld		6.3	29.5
Repurchases of ordinary shares		(300.0)	(100.0)
Dividends paid		(125.9)	(126.1)
Payment for Debt Extinguishment or Debt Prepayment Cost		(16.0)	(94.9)
Net cash provided by (used for) financing activities of continuing operations		(161.1)	(2,926.8)
Change in cash held for sale		27.0	(14.5)
Effect of exchange rate changes on cash and cash equivalents		(3.8)	45.0
Change in cash and cash equivalents		(7.6)	(75.2)
Cash and cash equivalents, beginning of period		86.3	216.9	$ 216.9
Cash and cash equivalents, end of period	78.7	78.7	141.7	86.3
Parent Company Guarantor
Condensed Financial Statements, Captions [Line Items]
Transfer of cash to nVent		0.0
Distribution of cash from nVent		0.0
Operating activities
Net cash provided by (used for) operating activities		101.1	165.9
Investing activities
Capital expenditures		0.0	0.0
Proceeds from the sale of property and equipment, net		0.0
(Payments due to) proceeds from the sale of businesses, net		0.0	0.0
Acquisitions, net of cash acquired		0.0	0.0
Intercompany Loan Activity, Net		30.8	0.0
Net cash provided by (used for) investing activities of continuing operations		30.8	0.0
Net cash provided by (used for) investing activities of discontinued operations		0.0	0.0
Net cash provided by (used for) investing activities		30.8	0.0
Financing activities
Net receipts of short-term borrowings			0.0
Net receipts (repayments) of commercial paper and revolving long-term debt		0.0	0.0
Repayments of Long-term Debt		0.0	0.0
Net change in advances to subsidiaries		287.8	30.8
Shares issued to employees, net of shares withheld		6.3	29.5
Repurchases of ordinary shares		(300.0)	(100.0)
Dividends paid		(125.9)	(126.1)
Payment for Debt Extinguishment or Debt Prepayment Cost		0.0	0.0
Net cash provided by (used for) financing activities of continuing operations		(131.8)	(165.8)
Change in cash held for sale		0.0	0.0
Effect of exchange rate changes on cash and cash equivalents		0.0	0.0
Change in cash and cash equivalents		0.1	0.1
Cash and cash equivalents, beginning of period		0.0	0.0	0.0
Cash and cash equivalents, end of period	0.1	0.1	0.1	0.0
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Transfer of cash to nVent		0.0
Distribution of cash from nVent		0.0
Operating activities
Net cash provided by (used for) operating activities		162.2	353.5
Investing activities
Capital expenditures		0.0	0.0
Proceeds from the sale of property and equipment, net		0.0
(Payments due to) proceeds from the sale of businesses, net		0.0	0.0
Acquisitions, net of cash acquired		0.0	0.0
Intercompany Loan Activity, Net		59.9	0.0
Net cash provided by (used for) investing activities of continuing operations		59.9	0.0
Net cash provided by (used for) investing activities of discontinued operations		0.0	0.0
Net cash provided by (used for) investing activities		59.9	0.0
Financing activities
Net receipts of short-term borrowings			0.0
Net receipts (repayments) of commercial paper and revolving long-term debt		0.0	0.0
Repayments of Long-term Debt		0.0	0.0
Net change in advances to subsidiaries		(222.1)	(353.5)
Shares issued to employees, net of shares withheld		0.0	0.0
Repurchases of ordinary shares		0.0	0.0
Dividends paid		0.0	0.0
Payment for Debt Extinguishment or Debt Prepayment Cost		0.0	0.0
Net cash provided by (used for) financing activities of continuing operations		(222.1)	(353.5)
Change in cash held for sale		0.0	0.0
Effect of exchange rate changes on cash and cash equivalents		0.0	0.0
Change in cash and cash equivalents		0.0	0.0
Cash and cash equivalents, beginning of period		0.0	0.0	0.0
Cash and cash equivalents, end of period	0.0	0.0	0.0	0.0
Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Transfer of cash to nVent		0.0
Distribution of cash from nVent		993.6
Operating activities
Net cash provided by (used for) operating activities		177.5	384.6
Investing activities
Capital expenditures		0.0	0.0
Proceeds from the sale of property and equipment, net		0.0
(Payments due to) proceeds from the sale of businesses, net		0.0	2,765.6
Acquisitions, net of cash acquired		0.0	0.0
Intercompany Loan Activity, Net		22.5	170.1
Net cash provided by (used for) investing activities of continuing operations		22.5	2,935.7
Net cash provided by (used for) investing activities of discontinued operations		0.0	0.0
Net cash provided by (used for) investing activities		22.5	2,935.7
Financing activities
Net receipts of short-term borrowings			0.0
Net receipts (repayments) of commercial paper and revolving long-term debt		43.8	(298.7)
Repayments of Long-term Debt		(675.1)	(1,567.8)
Net change in advances to subsidiaries		(517.0)	(1,363.2)
Shares issued to employees, net of shares withheld		0.0	0.0
Repurchases of ordinary shares		0.0	0.0
Dividends paid		0.0	0.0
Payment for Debt Extinguishment or Debt Prepayment Cost		(16.0)	(86.0)
Net cash provided by (used for) financing activities of continuing operations		(170.7)	(3,315.7)
Change in cash held for sale		0.0	0.0
Effect of exchange rate changes on cash and cash equivalents		(26.1)	46.4
Change in cash and cash equivalents		3.2	51.0
Cash and cash equivalents, beginning of period		0.0	0.0	0.0
Cash and cash equivalents, end of period	3.2	3.2	51.0	0.0
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Transfer of cash to nVent		(74.2)
Distribution of cash from nVent		0.0
Operating activities
Net cash provided by (used for) operating activities		272.6	481.2
Investing activities
Capital expenditures		(20.3)	(18.7)
Proceeds from the sale of property and equipment, net		(0.5)
(Payments due to) proceeds from the sale of businesses, net		(12.8)	0.0
Acquisitions, net of cash acquired		(0.9)	(45.9)
Intercompany Loan Activity, Net		490.6	256.2
Net cash provided by (used for) investing activities of continuing operations		456.1	191.6
Net cash provided by (used for) investing activities of discontinued operations		(7.1)	(35.2)
Net cash provided by (used for) investing activities		449.0	156.4
Financing activities
Net receipts of short-term borrowings			(0.5)
Net receipts (repayments) of commercial paper and revolving long-term debt		(13.6)	(676.8)
Repayments of Long-term Debt		0.0	(91.5)
Net change in advances to subsidiaries		(694.0)	29.7
Shares issued to employees, net of shares withheld		0.0	0.0
Repurchases of ordinary shares		0.0	0.0
Dividends paid		0.0	0.0
Payment for Debt Extinguishment or Debt Prepayment Cost		0.0	(8.9)
Net cash provided by (used for) financing activities of continuing operations		(781.8)	(748.0)
Change in cash held for sale		27.0	(14.5)
Effect of exchange rate changes on cash and cash equivalents		22.3	(1.4)
Change in cash and cash equivalents		(10.9)	(126.3)
Cash and cash equivalents, beginning of period		86.3	216.9	216.9
Cash and cash equivalents, end of period	75.4	75.4	90.6	86.3
Consolidation, Eliminations
Condensed Financial Statements, Captions [Line Items]
Transfer of cash to nVent		0.0
Distribution of cash from nVent		0.0
Operating activities
Net cash provided by (used for) operating activities		(541.5)	(1,229.9)
Investing activities
Capital expenditures		0.0	0.0
Proceeds from the sale of property and equipment, net		0.0
(Payments due to) proceeds from the sale of businesses, net		0.0	0.0
Acquisitions, net of cash acquired		0.0	0.0
Intercompany Loan Activity, Net		(603.8)	(426.3)
Net cash provided by (used for) investing activities of continuing operations		(603.8)	(426.3)
Net cash provided by (used for) investing activities of discontinued operations		0.0	0.0
Net cash provided by (used for) investing activities		(603.8)	(426.3)
Financing activities
Net receipts of short-term borrowings			0.0
Net receipts (repayments) of commercial paper and revolving long-term debt		0.0	0.0
Repayments of Long-term Debt		0.0	0.0
Net change in advances to subsidiaries		1,145.3	1,656.2
Shares issued to employees, net of shares withheld		0.0	0.0
Repurchases of ordinary shares		0.0	0.0
Dividends paid		0.0	0.0
Payment for Debt Extinguishment or Debt Prepayment Cost		0.0	0.0
Net cash provided by (used for) financing activities of continuing operations		1,145.3	1,656.2
Change in cash held for sale		0.0	0.0
Effect of exchange rate changes on cash and cash equivalents		0.0	0.0
Change in cash and cash equivalents		0.0	0.0
Cash and cash equivalents, beginning of period		0.0	0.0	0.0
Cash and cash equivalents, end of period	$ 0.0	$ 0.0	$ 0.0	$ 0.0