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, 2016	Sep. 26, 2015	Sep. 30, 2016	Sep. 26, 2015
Condensed Financial Statements, Captions [Line Items]
Net Income (Loss) Attributable to Parent	$ 141.0	$ 115.2	$ 391.2	$ 376.9
Net sales	1,210.7	1,112.8	3,701.9	3,327.4
Cost of goods sold	769.8	718.1	2,347.9	2,161.1
Gross profit	440.9	394.7	1,354.0	1,166.3
Selling, general and administrative	228.4	217.0	728.2	649.6
Research and development	29.7	24.8	86.9	72.3
Operating Income (Loss)	182.8	152.9	538.9	444.4
Other (income) expense:
Equity income of unconsolidated subsidiaries	(1.2)	(0.2)	(2.7)	(1.3)
Net interest expense	34.3	30.9	105.9	67.5
Income from continuing operations before income taxes	149.7	122.2	435.7	378.2
Provision for income taxes	32.2	27.5	93.7	85.1
Net Income (Loss) from Continuing Operations	117.5	94.7	342.0	293.1
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(22.9)	(20.5)	(48.6)	(88.6)
Discontinued Operation, Provision for Loss (Gain) on Disposal, Net of Tax	0.6	0.0	0.6	(4.8)
Comprehensive income (loss), net of tax
Net income	141.0	115.2	391.2	376.9
Changes in cumulative translation adjustment	(34.9)	85.8	(37.1)	238.4
Changes in market value of derivative financial instruments	(4.8)	(0.7)	(8.6)	(1.6)
Comprehensive income (loss) attributable to Pentair plc	171.1	28.7	419.7	136.9
Parent Company Guarantor
Condensed Financial Statements, Captions [Line Items]
Net Income (Loss) Attributable to Parent		115.2		376.9
Gross profit	0.0
Selling, general and administrative	0.0	17.7	1.7	30.4
Research and development			0.0
Operating Income (Loss)	0.0	(17.7)	(1.7)	(30.4)
Other (income) expense:
Net interest expense	0.0	0.0	0.0	0.0
Income from continuing operations before income taxes	117.5	94.7	341.9	292.4
Provision for income taxes	0.0	0.0	(0.1)	(0.7)
Net Income (Loss) from Continuing Operations	117.5	94.7	342.0	293.1
Comprehensive income (loss), net of tax
Net income	141.0	115.2	391.2	376.9
Changes in cumulative translation adjustment	(34.9)	85.8	(37.1)	238.4
Changes in market value of derivative financial instruments	(4.8)	(0.7)	(8.6)	(1.6)
Comprehensive income (loss) attributable to Pentair plc	171.1	28.7	419.7	136.9
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net Income (Loss) Attributable to Parent		132.9		406.6
Gross profit	0.0
Selling, general and administrative	0.0	0.1	0.0	0.2
Operating Income (Loss)	0.0	(0.1)	0.0	(0.2)
Other (income) expense:
Net interest expense	0.0	0.0	0.0	1.3
Income from continuing operations before income taxes	117.5	112.4	343.6	322.8
Provision for income taxes	0.0	0.0	0.0	0.0
Net Income (Loss) from Continuing Operations	117.5	112.4	343.6	322.8
Comprehensive income (loss), net of tax
Net income	141.0	132.9	392.8	406.6
Changes in cumulative translation adjustment	(34.9)	85.8	(37.1)	238.4
Changes in market value of derivative financial instruments	(4.8)	(0.7)	(8.6)	(1.6)
Comprehensive income (loss) attributable to Pentair plc	171.1	46.4	421.3	166.6
Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Net Income (Loss) Attributable to Parent		128.6		392.6
Gross profit	0.0
Selling, general and administrative	0.3	1.7	1.3	3.8
Operating Income (Loss)	(0.3)	(1.7)	(1.3)	(3.8)
Other (income) expense:
Net interest expense	27.8	18.0	83.9	21.8
Income from continuing operations before income taxes	117.5	108.1	343.6	308.8
Provision for income taxes	0.0	0.0	0.0	0.0
Net Income (Loss) from Continuing Operations	117.5	108.1	343.6	308.8
Comprehensive income (loss), net of tax
Net income	141.0	128.6	392.8	392.6
Changes in cumulative translation adjustment	(34.9)	85.8	(37.1)	238.4
Changes in market value of derivative financial instruments	(4.8)	(0.7)	(8.6)	(1.6)
Comprehensive income (loss) attributable to Pentair plc	171.1	42.1	421.3	152.6
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net Income (Loss) Attributable to Parent		152.7		433.7
Net sales	1,210.7	1,112.8	3,701.9	3,327.4
Cost of goods sold	769.8	718.1	2,347.9	2,161.1
Gross profit	440.9	394.7	1,354.0	1,166.3
Selling, general and administrative	228.1	197.5	725.2	615.2
Research and development	29.7	24.8	86.9	72.3
Operating Income (Loss)	183.1	172.4	541.9	478.8
Other (income) expense:
Equity income of unconsolidated subsidiaries	(1.2)	(0.2)	(2.7)	(1.3)
Net interest expense	6.5	12.9	22.0	44.4
Income from continuing operations before income taxes	177.8	159.7	522.6	435.7
Provision for income taxes	32.2	27.5	93.8	85.8
Net Income (Loss) from Continuing Operations	145.6	132.2	428.8	349.9
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(22.9)	(20.5)	(48.6)	(88.6)
Discontinued Operation, Provision for Loss (Gain) on Disposal, Net of Tax	0.6		0.6	(4.8)
Comprehensive income (loss), net of tax
Net income	169.1	152.7	478.0	433.7
Changes in cumulative translation adjustment	(34.9)	85.8	(37.1)	238.4
Changes in market value of derivative financial instruments	(4.8)	(0.7)	(8.6)	(1.6)
Comprehensive income (loss) attributable to Pentair plc	199.2	66.2	506.5	193.7
Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net Income (Loss) Attributable to Parent		(414.2)		(1,232.9)
Gross profit	0.0
Other (income) expense:
Income from continuing operations before income taxes	(380.6)	(352.7)	(1,116.0)	(981.5)
Net Income (Loss) from Continuing Operations	(380.6)	(352.7)	(1,116.0)	(981.5)
Comprehensive income (loss), net of tax
Net income	(451.1)	(414.2)	(1,263.6)	(1,232.9)
Changes in cumulative translation adjustment	104.7	(257.4)	111.3	(715.2)
Changes in market value of derivative financial instruments	14.4	2.1	25.8	4.8
Comprehensive income (loss) attributable to Pentair plc	(541.4)	(154.7)	(1,349.1)	(512.9)
Discontinued Operations [Member]
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	70.5
Discontinued Operations [Member] | Parent Company Guarantor
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	(23.5)	(20.5)	(49.2)	(83.8)
Discontinued Operations [Member] | Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	(23.5)	(20.5)	(49.2)	(83.8)
Discontinued Operations [Member] | Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	(23.5)	(20.5)	(49.2)	(83.8)
Discontinued Operations [Member] | Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries		61.5	147.6	251.4
Continuing Operations [Member] | Parent Company Guarantor
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	117.5	112.4	343.6	322.8
Continuing Operations [Member] | Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	117.5	112.5	343.6	324.3
Continuing Operations [Member] | Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	145.6	127.8	428.8	334.4
Continuing Operations [Member] | Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	$ (380.6)	$ (352.7)	$ (1,116.0)	$ (981.5)