Supplemental Guarantor Information - Condensed Consolidating Statement of Cash Flows (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating activities
Net cash provided by (used for) operating activities	$ 96.7	$ 171.9
Investing activities
Capital expenditures	(29.8)	(20.3)
Proceeds from sale of property and equipment	0.4	(0.5)
Proceeds from (payments due to) the sale of businesses, net	0.7	(12.8)
Acquisitions, net of cash acquired	(284.5)	(0.9)
Net intercompany loan activity	0.0	0.0
Payments for (Proceeds from) Other Investing Activities	(1.5)	0.0
Net cash provided by (used for) investing activities of continuing operations	(314.7)	(34.5)
Net cash used for investing activities of discontinued operations	0.0	(7.1)
Net cash used for investing activities	(314.7)	(41.6)
Financing activities
Net receipts of commercial paper and revolving long-term debt	32.9	30.2
Proceeds from long-term debt	400.0	0.0
Repayments of long-term debt	0.0	675.1
Debt issuance costs	5.7	0.0
Premium paid on early extinguishment of debt	0.0	16.0
Cash Divested from Deconsolidation	0.0	(74.2)
Distribution of cash from nVent	0.0	993.6
Net change in advances to subsidiaries	0.0	0.0
Shares issued to employees, net of shares withheld	7.2	6.3
Repurchases of ordinary shares	(150.0)	(300.0)
Dividends paid	(62.0)	(125.9)
Net cash provided by financing activities of continuing operations	222.4	(161.1)
Change in cash held for sale	0.0	27.0
Effect of exchange rate changes on cash and cash equivalents	1.8	(3.8)
Change in cash and cash equivalents	6.2	(7.6)
Cash and cash equivalents, beginning of period	74.3	86.3
Cash and cash equivalents, end of period	80.5	78.7
Parent Company Guarantor
Operating activities
Net cash provided by (used for) operating activities	157.2	101.1
Investing activities
Capital expenditures	0.0	0.0
Proceeds from sale of property and equipment	0.0	0.0
Proceeds from (payments due to) the sale of businesses, net	0.0	0.0
Acquisitions, net of cash acquired	0.0	0.0
Net intercompany loan activity	0.0	30.8
Payments for (Proceeds from) Other Investing Activities	0.0
Net cash provided by (used for) investing activities of continuing operations		30.8
Net cash used for investing activities of discontinued operations		0.0
Net cash used for investing activities	0.0	30.8
Financing activities
Net receipts of commercial paper and revolving long-term debt	0.0	0.0
Proceeds from long-term debt	0.0
Repayments of long-term debt		0.0
Debt issuance costs	0.0
Premium paid on early extinguishment of debt		0.0
Cash Divested from Deconsolidation		0.0
Distribution of cash from nVent		0.0
Net change in advances to subsidiaries	47.8	287.8
Shares issued to employees, net of shares withheld	7.2	6.3
Repurchases of ordinary shares	(150.0)	(300.0)
Dividends paid	(62.0)	(125.9)
Net cash provided by financing activities of continuing operations	(157.0)	(131.8)
Change in cash held for sale		0.0
Effect of exchange rate changes on cash and cash equivalents	0.0	0.0
Change in cash and cash equivalents	0.2	0.1
Cash and cash equivalents, beginning of period	0.1	0.0
Cash and cash equivalents, end of period	0.3	0.1
Guarantor Subsidiaries
Operating activities
Net cash provided by (used for) operating activities	170.4	162.2
Investing activities
Capital expenditures	0.0	0.0
Proceeds from sale of property and equipment	0.0	0.0
Proceeds from (payments due to) the sale of businesses, net	0.0	0.0
Acquisitions, net of cash acquired	0.0	0.0
Net intercompany loan activity	0.0	59.9
Payments for (Proceeds from) Other Investing Activities	0.0
Net cash provided by (used for) investing activities of continuing operations		59.9
Net cash used for investing activities of discontinued operations		0.0
Net cash used for investing activities	0.0	59.9
Financing activities
Net receipts of commercial paper and revolving long-term debt	0.0	0.0
Proceeds from long-term debt	0.0
Repayments of long-term debt		0.0
Debt issuance costs	0.0
Premium paid on early extinguishment of debt		0.0
Cash Divested from Deconsolidation		0.0
Distribution of cash from nVent		0.0
Net change in advances to subsidiaries	(170.4)	(222.1)
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
Net cash provided by financing activities of continuing operations	(170.4)	(222.1)
Change in cash held for sale		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
Cash and cash equivalents, end of period	0.0	0.0
Subsidiary Issuer
Operating activities
Net cash provided by (used for) operating activities	179.1	177.5
Investing activities
Capital expenditures	0.0	0.0
Proceeds from sale of property and equipment	0.0	0.0
Proceeds from (payments due to) the sale of businesses, net	0.0	0.0
Acquisitions, net of cash acquired	0.0	0.0
Net intercompany loan activity	(604.3)	22.5
Payments for (Proceeds from) Other Investing Activities	0.0
Net cash provided by (used for) investing activities of continuing operations		22.5
Net cash used for investing activities of discontinued operations		0.0
Net cash used for investing activities	(604.3)	22.5
Financing activities
Net receipts of commercial paper and revolving long-term debt	55.0	43.8
Proceeds from long-term debt	400.0
Repayments of long-term debt		675.1
Debt issuance costs	5.7
Premium paid on early extinguishment of debt		16.0
Cash Divested from Deconsolidation		0.0
Distribution of cash from nVent		993.6
Net change in advances to subsidiaries	(24.3)	(517.0)
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
Net cash provided by financing activities of continuing operations	425.0	(170.7)
Change in cash held for sale		0.0
Effect of exchange rate changes on cash and cash equivalents	0.2	(26.1)
Change in cash and cash equivalents	0.0	3.2
Cash and cash equivalents, beginning of period	0.1	0.0
Cash and cash equivalents, end of period	0.1	3.2
Non-Guarantor Subsidiaries
Operating activities
Net cash provided by (used for) operating activities	104.3	272.6
Investing activities
Capital expenditures	(29.8)	(20.3)
Proceeds from sale of property and equipment	0.4	(0.5)
Proceeds from (payments due to) the sale of businesses, net	0.7	(12.8)
Acquisitions, net of cash acquired	(284.5)	(0.9)
Net intercompany loan activity	(21.9)	490.6
Payments for (Proceeds from) Other Investing Activities	1.5
Net cash provided by (used for) investing activities of continuing operations		456.1
Net cash used for investing activities of discontinued operations		(7.1)
Net cash used for investing activities	(336.6)	449.0
Financing activities
Net receipts of commercial paper and revolving long-term debt	(22.1)	(13.6)
Proceeds from long-term debt	0.0
Repayments of long-term debt		0.0
Debt issuance costs	0.0
Premium paid on early extinguishment of debt		0.0
Cash Divested from Deconsolidation		(74.2)
Distribution of cash from nVent		0.0
Net change in advances to subsidiaries	258.8	(694.0)
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
Net cash provided by financing activities of continuing operations	236.7	(781.8)
Change in cash held for sale		27.0
Effect of exchange rate changes on cash and cash equivalents	1.6	22.3
Change in cash and cash equivalents	6.0	(10.9)
Cash and cash equivalents, beginning of period	74.1	86.3
Cash and cash equivalents, end of period	80.1	75.4
Consolidation, Eliminations
Operating activities
Net cash provided by (used for) operating activities	(514.3)	(541.5)
Investing activities
Capital expenditures	0.0	0.0
Proceeds from sale of property and equipment	0.0	0.0
Proceeds from (payments due to) the sale of businesses, net	0.0	0.0
Acquisitions, net of cash acquired	0.0	0.0
Net intercompany loan activity	626.2	(603.8)
Payments for (Proceeds from) Other Investing Activities	0.0
Net cash provided by (used for) investing activities of continuing operations		(603.8)
Net cash used for investing activities of discontinued operations		0.0
Net cash used for investing activities	626.2	(603.8)
Financing activities
Net receipts of commercial paper and revolving long-term debt	0.0	0.0
Proceeds from long-term debt	0.0
Repayments of long-term debt		0.0
Debt issuance costs	0.0
Premium paid on early extinguishment of debt		0.0
Cash Divested from Deconsolidation		0.0
Distribution of cash from nVent		0.0
Net change in advances to subsidiaries	(111.9)	1,145.3
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
Net cash provided by financing activities of continuing operations	(111.9)	1,145.3
Change in cash held for sale		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
Cash and cash equivalents, end of period	$ 0.0	$ 0.0