Financial Statements of Parent Company Guarantor - Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 1,265.3	$ 1,301.2	$ 2,448.8	$ 2,491.2
Cost of goods sold	782.1	819.4	1,543.3	1,578.1
Gross profit	483.2	481.8	905.5	913.1
Selling, general and administrative	241.7	249.7	495.6	499.8
Research and development	28.7	28.7	58.7	57.2
Operating Income (Loss)	212.8	203.4	351.2	356.1
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	(0.4)	(1.1)	(0.6)	(1.5)
Loss on early extinguishment of debt	101.4	0.0	101.4	0.0
Net interest expense	25.3	35.4	60.3	71.6
Income from continuing operations before income taxes	86.5	169.1	190.1	286.0
Provision for income taxes	18.2	36.4	41.1	61.5
Net Income (Loss) from Continuing Operations	68.3	132.7	149.0	224.5
(Loss) income from discontinued operations, net of tax	(5.2)	10.1	1.9	25.7
Gain from sale of discontinued operations, net of tax	200.6	0.0	200.6	0.0
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	0.0	0.0	0.0	0.0
Comprehensive income, net of tax
Net income	263.7	142.8	351.5	250.2
Changes in cumulative translation adjustment	(392.6)	25.8	(468.3)	(2.2)
Changes in market value of derivative financial instruments	(0.9)	10.9	0.7	(3.8)
Comprehensive income (loss) attributable to Pentair plc	655.4	127.9	820.5	248.6
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	4.3	0.0	(3.8)	7.1
Research and development	0.0	0.0	0.0	0.0
Operating Income (Loss)	(4.3)		3.8	(7.1)
Loss (earnings) from continuing operations of investment in subsidiaries	(72.6)	(132.6)	(145.2)	(231.5)
Other (income) expense:
Equity income of unconsolidated subsidiaries	0.0	0.0	0.0	0.0
Loss on early extinguishment of debt	0.0		0.0
Net interest expense	0.0	0.0	0.0	0.0
Income from continuing operations before income taxes	68.3	132.6	149.0	224.4
Provision for income taxes	0.0	(0.1)	0.0	(0.1)
Net Income (Loss) from Continuing Operations	68.3	132.7	149.0	224.5
(Loss) income from discontinued operations, net of tax	0.0	0.0	0.0	0.0
Gain from sale of discontinued operations, net of tax	0.0		0.0
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	195.4	10.1	202.5	25.7
Comprehensive income, net of tax
Net income	263.7	142.8	351.5	250.2
Changes in cumulative translation adjustment	(392.6)	25.8	(468.3)	(2.2)
Changes in market value of derivative financial instruments	(0.9)	10.9	0.7	(3.8)
Comprehensive income (loss) attributable to Pentair plc	655.4	127.9	820.5	248.6
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	0.1	0.0	0.2	0.0
Research and development	0.0	0.0	0.0	0.0
Operating Income (Loss)	(0.1)		(0.2)	0.0
Loss (earnings) from continuing operations of investment in subsidiaries	(72.7)	(132.6)	(145.4)	(231.5)
Other (income) expense:
Equity income of unconsolidated subsidiaries	0.0	0.0	0.0	0.0
Loss on early extinguishment of debt	0.0		0.0
Net interest expense	0.0	0.0	0.0	0.0
Income from continuing operations before income taxes	72.6	132.6	145.2	231.5
Provision for income taxes	0.0	0.0	0.0	0.0
Net Income (Loss) from Continuing Operations	72.6	132.6	145.2	231.5
(Loss) income from discontinued operations, net of tax	0.0	0.0	0.0	0.0
Gain from sale of discontinued operations, net of tax	0.0		0.0
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	195.4	10.1	202.5	25.7
Comprehensive income, net of tax
Net income	268.0	142.7	347.7	257.2
Changes in cumulative translation adjustment	(392.6)	25.8	(468.3)	(2.2)
Changes in market value of derivative financial instruments	(0.9)	10.9	0.7	(3.8)
Comprehensive income (loss) attributable to Pentair plc	659.7	127.8	816.7	255.6
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	0.1	0.0	0.4	0.9
Research and development	0.0	0.0	0.0	0.0
Operating Income (Loss)	(0.1)		(0.4)	(0.9)
Loss (earnings) from continuing operations of investment in subsidiaries	(210.9)	(161.4)	(312.3)	(288.6)
Other (income) expense:
Equity income of unconsolidated subsidiaries	0.0	0.0	0.0	0.0
Loss on early extinguishment of debt	91.0		91.0
Net interest expense	21.9	28.8	50.3	56.2
Income from continuing operations before income taxes	97.9	132.6	170.6	231.5
Provision for income taxes	0.0	0.0	0.0	0.0
Net Income (Loss) from Continuing Operations	97.9	132.6	170.6	231.5
(Loss) income from discontinued operations, net of tax	0.0	0.0	0.0	0.0
Gain from sale of discontinued operations, net of tax	0.0		0.0
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	195.4	10.1	202.5	25.7
Comprehensive income, net of tax
Net income	293.3	142.7	373.1	257.2
Changes in cumulative translation adjustment	(392.6)	25.8	(468.3)	(2.2)
Changes in market value of derivative financial instruments	(0.9)	10.9	0.7	(3.8)
Comprehensive income (loss) attributable to Pentair plc	685.0	127.8	842.1	255.6
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	1,265.3	1,301.2	2,448.8	2,491.2
Cost of goods sold	782.1	819.4	1,543.3	1,578.1
Gross profit	483.2	481.8	905.5	913.1
Selling, general and administrative	237.2	249.7	498.8	491.8
Research and development	28.7	28.7	58.7	57.2
Operating Income (Loss)	217.3	203.4	348.0	364.1
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	(0.4)	(1.1)	(0.6)	(1.5)
Loss on early extinguishment of debt	10.4		10.4
Net interest expense	3.4	6.6	10.0	15.4
Income from continuing operations before income taxes	203.9	197.9	328.2	350.2
Provision for income taxes	18.2	36.5	41.1	61.6
Net Income (Loss) from Continuing Operations	185.7	161.4	287.1	288.6
(Loss) income from discontinued operations, net of tax	(5.2)	10.1	1.9	25.7
Gain from sale of discontinued operations, net of tax	200.6		200.6
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	0.0	0.0	0.0	0.0
Comprehensive income, net of tax
Net income	381.1	171.5	489.6	314.3
Changes in cumulative translation adjustment	(392.6)	25.8	(468.3)	(2.2)
Changes in market value of derivative financial instruments	(0.9)	10.9	0.7	(3.8)
Comprehensive income (loss) attributable to Pentair plc	772.8	156.6	958.6	312.7
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	356.2	426.6	602.9	751.6
Other (income) expense:
Equity income of unconsolidated subsidiaries	0.0	0.0	0.0	0.0
Loss on early extinguishment of debt	0.0		0.0
Net interest expense	0.0	0.0	0.0	0.0
Income from continuing operations before income taxes	(356.2)	(426.6)	(602.9)	(751.6)
Provision for income taxes	0.0	0.0	0.0	0.0
Net Income (Loss) from Continuing Operations	(356.2)	(426.6)	(602.9)	(751.6)
(Loss) income from discontinued operations, net of tax	0.0	0.0	0.0	0.0
Gain from sale of discontinued operations, net of tax	0.0		0.0
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	(586.2)	(30.3)	(607.5)	(77.1)
Comprehensive income, net of tax
Net income	(942.4)	(456.9)	(1,210.4)	(828.7)
Changes in cumulative translation adjustment	1,177.8	(77.4)	1,404.9	6.6
Changes in market value of derivative financial instruments	2.7	(32.7)	(2.1)	11.4
Comprehensive income (loss) attributable to Pentair plc	$ (2,117.5)	$ (412.2)	$ (2,617.4)	$ (823.9)