Financial Statements of Parent Company Guarantor - Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 1,226.8	$ 1,210.7	$ 3,675.6	$ 3,701.9
Cost of goods sold	771.5	769.8	2,314.8	2,347.9
Gross profit	455.3	440.9	1,360.8	1,354.0
Selling, general and administrative	234.7	228.4	730.3	728.2
Research and development	28.4	29.7	87.1	86.9
Operating Income (Loss)	192.2	182.8	543.4	538.9
Loss (earnings) from continuing operations of investment in subsidiaries	0.0	0.0	0.0	0.0
Other (income) expense:
Equity income of unconsolidated subsidiaries	(0.3)	(1.2)	(0.9)	(2.7)
Loss on sale of business	3.8	0.0	3.8	0.0
Loss on early extinguishment of debt	0.0	0.0	101.4	0.0
Net interest expense	13.9	34.3	74.2	105.9
Income from continuing operations before income taxes	174.8	149.7	364.9	435.7
Provision for income taxes	47.7	32.2	88.8	93.7
Net Income (Loss) from Continuing Operations	127.1	117.5	276.1	342.0
Income from discontinued operations, net of tax	0.0	22.9	1.9	48.6
(Loss) gain from sale of discontinued operations, net of tax	(1.7)	0.6	198.9	0.6
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	0.0	0.0	0.0	0.0
Comprehensive income, net of tax
Net income	125.4	141.0	476.9	391.2
Changes in cumulative translation adjustment	(34.5)	(34.9)	(502.8)	(37.1)
Changes in market value of derivative financial instruments	(3.0)	(4.8)	(2.3)	(8.6)
Comprehensive income (loss) attributable to Pentair plc	156.9	171.1	977.4	419.7
Parent Company Guarantor
Condensed Financial Statements, Captions [Line Items]
Net sales	0.0	0.0	0.0	0.0
Cost of goods sold	0.0	0.0	0.0	0.0
Gross profit	0.0	0.0	0.0	0.0
Selling, general and administrative	4.2	0.0	0.5	1.7
Research and development	0.0	0.0	0.0	0.0
Operating Income (Loss)	(4.2)	0.0	(0.5)	(1.7)
Loss (earnings) from continuing operations of investment in subsidiaries	(130.9)	(117.5)	(276.2)	(343.6)
Other (income) expense:
Equity income of unconsolidated subsidiaries	0.0	0.0	0.0	0.0
Loss on sale of business	0.0		0.0
Loss on early extinguishment of debt			0.0
Net interest expense	0.0	0.0	0.0	0.0
Income from continuing operations before income taxes	126.7	117.5	275.7	341.9
Provision for income taxes	(0.4)	0.0	(0.4)	(0.1)
Net Income (Loss) from Continuing Operations	127.1	117.5	276.1	342.0
Income from discontinued operations, net of tax		0.0	0.0	0.0
(Loss) gain from sale of discontinued operations, net of tax	0.0		0.0
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	(1.7)	23.5	200.8	49.2
Comprehensive income, net of tax
Net income	125.4	141.0	476.9	391.2
Changes in cumulative translation adjustment	(34.5)	(34.9)	(502.8)	(37.1)
Changes in market value of derivative financial instruments	(3.0)	(4.8)	(2.3)	(8.6)
Comprehensive income (loss) attributable to Pentair plc	156.9	171.1	977.4	419.7
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	0.0	0.0	0.0	0.0
Cost of goods sold	0.0	0.0	0.0	0.0
Gross profit	0.0	0.0	0.0	0.0
Selling, general and administrative	0.0	0.0	0.2	0.0
Research and development	0.0	0.0	0.0	0.0
Operating Income (Loss)	0.0	0.0	(0.2)	0.0
Loss (earnings) from continuing operations of investment in subsidiaries	(130.7)	(117.5)	(276.1)	(343.6)
Other (income) expense:
Equity income of unconsolidated subsidiaries	0.0	0.0	0.0	0.0
Loss on sale of business	0.0		0.0
Loss on early extinguishment of debt			0.0
Net interest expense	(0.2)	0.0	(0.3)	0.0
Income from continuing operations before income taxes	130.9	117.5	276.2	343.6
Provision for income taxes	0.0	0.0	0.0	0.0
Net Income (Loss) from Continuing Operations	130.9	117.5	276.2	343.6
Income from discontinued operations, net of tax		0.0	0.0	0.0
(Loss) gain from sale of discontinued operations, net of tax	0.0		0.0
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	(1.7)	23.5	200.8	49.2
Comprehensive income, net of tax
Net income	129.2	141.0	477.0	392.8
Changes in cumulative translation adjustment	(34.5)	(34.9)	(502.8)	(37.1)
Changes in market value of derivative financial instruments	(3.0)	(4.8)	(2.3)	(8.6)
Comprehensive income (loss) attributable to Pentair plc	160.7	171.1	977.5	421.3
Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Net sales	0.0	0.0	0.0	0.0
Cost of goods sold	0.0	0.0	0.0	0.0
Gross profit	0.0	0.0	0.0	0.0
Selling, general and administrative	0.0	0.3	0.3	1.3
Research and development	0.0	0.0	0.0	0.0
Operating Income (Loss)	0.0	(0.3)	(0.3)	(1.3)
Loss (earnings) from continuing operations of investment in subsidiaries	(115.3)	(145.6)	(427.5)	(428.8)
Other (income) expense:
Equity income of unconsolidated subsidiaries	0.0	0.0	0.0	0.0
Loss on sale of business	0.0		0.0
Loss on early extinguishment of debt			91.0
Net interest expense	10.3	27.8	60.6	83.9
Income from continuing operations before income taxes	105.0	117.5	275.6	343.6
Provision for income taxes	0.0	0.0	0.0	0.0
Net Income (Loss) from Continuing Operations	105.0	117.5	275.6	343.6
Income from discontinued operations, net of tax		0.0	0.0	0.0
(Loss) gain from sale of discontinued operations, net of tax	0.0		0.0
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	(1.7)	23.5	200.8	49.2
Comprehensive income, net of tax
Net income	103.3	141.0	476.4	392.8
Changes in cumulative translation adjustment	(34.5)	(34.9)	(502.8)	(37.1)
Changes in market value of derivative financial instruments	(3.0)	(4.8)	(2.3)	(8.6)
Comprehensive income (loss) attributable to Pentair plc	134.8	171.1	976.9	421.3
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	1,226.8	1,210.7	3,675.6	3,701.9
Cost of goods sold	771.5	769.8	2,314.8	2,347.9
Gross profit	455.3	440.9	1,360.8	1,354.0
Selling, general and administrative	230.5	228.1	729.3	725.2
Research and development	28.4	29.7	87.1	86.9
Operating Income (Loss)	196.4	183.1	544.4	541.9
Loss (earnings) from continuing operations of investment in subsidiaries	0.0	0.0	0.0	0.0
Other (income) expense:
Equity income of unconsolidated subsidiaries	(0.3)	(1.2)	(0.9)	(2.7)
Loss on sale of business	3.8		3.8
Loss on early extinguishment of debt			10.4
Net interest expense	3.8	6.5	13.9	22.0
Income from continuing operations before income taxes	189.1	177.8	517.2	522.6
Provision for income taxes	48.1	32.2	89.2	93.8
Net Income (Loss) from Continuing Operations	141.0	145.6	428.0	428.8
Income from discontinued operations, net of tax		22.9	1.9	48.6
(Loss) gain from sale of discontinued operations, net of tax	(1.7)	0.6	198.9	0.6
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	0.0	0.0	0.0	0.0
Comprehensive income, net of tax
Net income	139.3	169.1	628.8	478.0
Changes in cumulative translation adjustment	(34.5)	(34.9)	(502.8)	(37.1)
Changes in market value of derivative financial instruments	(3.0)	(4.8)	(2.3)	(8.6)
Comprehensive income (loss) attributable to Pentair plc	170.8	199.2	1,129.3	506.5
Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales	0.0	0.0	0.0	0.0
Cost of goods sold	0.0	0.0	0.0	0.0
Gross profit	0.0	0.0	0.0	0.0
Selling, general and administrative	0.0	0.0	0.0	0.0
Research and development	0.0	0.0	0.0	0.0
Operating Income (Loss)	0.0		0.0	0.0
Loss (earnings) from continuing operations of investment in subsidiaries	376.9	380.6	979.8	1,116.0
Other (income) expense:
Equity income of unconsolidated subsidiaries	0.0	0.0	0.0	0.0
Loss on sale of business	0.0		0.0
Loss on early extinguishment of debt			0.0
Net interest expense	0.0	0.0	0.0	0.0
Income from continuing operations before income taxes	(376.9)	(380.6)	(979.8)	(1,116.0)
Provision for income taxes	0.0	0.0	0.0	0.0
Net Income (Loss) from Continuing Operations	(376.9)	(380.6)	(979.8)	(1,116.0)
Income from discontinued operations, net of tax		0.0	0.0	0.0
(Loss) gain from sale of discontinued operations, net of tax	0.0		0.0
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	5.1	(70.5)	(602.4)	(147.6)
Comprehensive income, net of tax
Net income	(371.8)	(451.1)	(1,582.2)	(1,263.6)
Changes in cumulative translation adjustment	103.5	104.7	1,508.4	111.3
Changes in market value of derivative financial instruments	9.0	14.4	6.9	25.8
Comprehensive income (loss) attributable to Pentair plc	$ (466.3)	$ (541.4)	$ (3,083.7)	$ (1,349.1)