Financial Statements of Parent Company Guarantor - Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Mar. 30, 2013	Sep. 27, 2014	Sep. 28, 2013
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 1,758.4	$ 1,713.3		$ 5,236.5	$ 5,168.7
Cost of goods sold	1,133.7	1,098.6		3,401.4	3,429.1
Gross profit	624.7	614.7		1,835.1	1,739.6
Selling, general and administrative	328.8	353.4		1,071.0	1,143.5
Research and development	28.5	31.3		88.2	94.8
Operating income (loss)	267.4	230.0		675.9	501.3
Income (Loss) from Equity Method Investments	(0.3)	(0.5)		(0.9)	(1.7)
Other (income) expense:
Loss (gain) on sale of businesses	0	(0.1)	(16.7)	0.2	(16.8)
Net interest expense	17.1	17.5		51.1	53.8
Income before income taxes and noncontrolling interest	(250.6)	(213.1)		(625.5)	(466.0)
Provision for income taxes	58.1	46.7		148.3	112.9
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	192.5	166.4		477.2	353.1
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(1.6)	(7.8)		(2.6)	(29.8)
Discontinued Operation, Provision for Loss (Gain) on Disposal, Net of Tax	(380.1)	0		(385.7)	0
Noncontrolling interest	0	1.4		0	4.3
Net income (loss) attributable to Pentair plc	(186.0)	172.8		94.1	378.6
Income (Loss) from Continuing Operations Attributable to Parent	192.5	165.0		477.2	348.8
Comprehensive income (loss), net of tax
Net income	(186.0)	174.2		94.1	382.9
Changes in cumulative translation adjustment	178.8	(89.1)		190.3	29.1
Changes in market value of derivative financial instruments	0.8	(0.6)		1.2	(0.3)
Total comprehensive income (loss)	(364.0)	262.7		(95.0)	353.5
Less: Comprehensive income attributable to noncontrolling interest	0	2.6		0	5.0
Comprehensive income (loss) attributable to Pentair plc	(364.0)	260.1		(95.0)	348.5
Parent Company Guarantor
Condensed Financial Statements, Captions [Line Items]
Selling, general and administrative	3.2	(0.7)		10.6	(1.5)
Operating income (loss)	(3.2)	0.7		(10.6)	1.5
Other (income) expense:
Net interest expense	0	1.3		0.7	4.4
Income before income taxes and noncontrolling interest	(192.5)	(164.9)		(477.2)	(348.4)
Provision for income taxes	0	(0.1)		0	(0.4)
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	192.5	165.0		477.2	348.8
Net income (loss) attributable to Pentair plc	(186.0)	172.8		94.1	378.6
Income (Loss) from Continuing Operations Attributable to Parent	192.5	165.0		477.2	348.8
Comprehensive income (loss), net of tax
Net income	(186.0)	172.8		94.1	378.6
Changes in cumulative translation adjustment	178.8	(87.9)		190.3	29.8
Changes in market value of derivative financial instruments	0.8	(0.6)		1.2	(0.3)
Total comprehensive income (loss)		260.1			348.5
Less: Comprehensive income attributable to noncontrolling interest		0			0
Comprehensive income (loss) attributable to Pentair plc	(364.0)	260.1		(95.0)	348.5
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Selling, general and administrative	1.5			4.2
Operating income (loss)	(1.5)			(4.2)
Other (income) expense:
Net interest expense	0.9			1.2
Income before income taxes and noncontrolling interest	(195.7)			(488.5)
Provision for income taxes	0			0
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	195.7			488.5
Net income (loss) attributable to Pentair plc	(182.8)			105.4
Income (Loss) from Continuing Operations Attributable to Parent	195.7			488.5
Comprehensive income (loss), net of tax
Net income	(182.8)			105.4
Changes in cumulative translation adjustment	178.8			190.3
Changes in market value of derivative financial instruments	0.8			1.2
Comprehensive income (loss) attributable to Pentair plc	(360.8)			(83.7)
Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Selling, general and administrative	0.8	3.1		6.8	10.1
Operating income (loss)	(0.8)	(3.1)		(6.8)	(10.1)
Other (income) expense:
Net interest expense	1.0	0.6		2.0	6.7
Income before income taxes and noncontrolling interest	(204.5)	(165.8)		(475.2)	(349.8)
Provision for income taxes	0	1.3		1.0	1.3
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	204.5	164.5		474.2	348.5
Net income (loss) attributable to Pentair plc	(174.0)	172.3		91.1	378.3
Income (Loss) from Continuing Operations Attributable to Parent	204.5	164.5		474.2	348.5
Comprehensive income (loss), net of tax
Net income	(174.0)	172.3		91.1	378.3
Changes in cumulative translation adjustment	178.8	(87.9)		190.3	29.8
Changes in market value of derivative financial instruments	0.8	(0.6)		1.2	(0.3)
Total comprehensive income (loss)		259.6			348.2
Less: Comprehensive income attributable to noncontrolling interest		0			0
Comprehensive income (loss) attributable to Pentair plc	(352.0)	259.6		(98.0)	348.2
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	1,758.4	1,713.3		5,236.5	5,168.7
Cost of goods sold	1,133.7	1,098.6		3,401.4	3,429.1
Gross profit	624.7	614.7		1,835.1	1,739.6
Selling, general and administrative	323.3	351.0		1,049.4	1,134.9
Research and development	28.5	31.3		88.2	94.8
Operating income (loss)	272.9	232.4		697.5	509.9
Income (Loss) from Equity Method Investments	(0.3)	(0.5)		(0.9)	(1.7)
Other (income) expense:
Loss (gain) on sale of businesses		(0.1)		0.2	(16.8)
Net interest expense	15.2	15.6		47.2	42.7
Income before income taxes and noncontrolling interest	(258.0)	(217.4)		(651.0)	(485.7)
Provision for income taxes	58.1	45.5		147.3	112.0
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	199.9	171.9		503.7	373.7
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(1.6)	(7.8)		(2.6)	29.8
Discontinued Operation, Provision for Loss (Gain) on Disposal, Net of Tax	(380.1)			(385.7)
Noncontrolling interest		1.4			4.3
Net income (loss) attributable to Pentair plc	(178.6)	178.3		120.6	399.2
Income (Loss) from Continuing Operations Attributable to Parent	199.9	170.5		503.7	369.4
Comprehensive income (loss), net of tax
Net income	(178.6)	179.7		120.6	403.5
Changes in cumulative translation adjustment	178.8	(89.1)		190.3	29.1
Changes in market value of derivative financial instruments	0.8	(0.6)		1.2	(0.3)
Total comprehensive income (loss)		268.2			374.1
Less: Comprehensive income attributable to noncontrolling interest		2.6			5.0
Comprehensive income (loss) attributable to Pentair plc	(356.6)	265.6		(68.5)	369.1
Eliminations
Other (income) expense:
Income before income taxes and noncontrolling interest	600.1	(335.0)		1,466.4	(717.9)
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	(600.1)	(335.0)		(1,466.4)	(717.9)
Net income (loss) attributable to Pentair plc	535.4	(350.6)		(317.1)	(777.5)
Income (Loss) from Continuing Operations Attributable to Parent	(600.1)	(335.0)		(1,466.4)	(717.9)
Comprehensive income (loss), net of tax
Net income	535.4	(350.6)		(317.1)	777.5
Changes in cumulative translation adjustment	(536.4)	175.8		(570.9)	59.6
Changes in market value of derivative financial instruments	(2.4)	1.2		(3.6)	(0.6)
Total comprehensive income (loss)		(525.2)			717.3
Less: Comprehensive income attributable to noncontrolling interest		0			0
Comprehensive income (loss) attributable to Pentair plc	1,069.4	(525.2)		250.2	717.3
Continuing Operations [Member] | Parent Company Guarantor
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	(195.7)	(165.5)		(488.5)	(351.3)
Continuing Operations [Member] | Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	(198.1)			(493.9)
Continuing Operations [Member] | Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	(206.3)	(169.5)		(484.0)	(366.6)
Continuing Operations [Member] | Eliminations
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	600.1	335.0		1,466.4	717.9
Discontinued Operations [Member] | Parent Company Guarantor
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	(378.5)	7.8		(383.1)	29.8
Discontinued Operations [Member] | Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	(378.5)			(383.1)
Discontinued Operations [Member] | Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	(378.5)	7.8		(383.1)	29.8
Discontinued Operations [Member] | Eliminations
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	$ 1,135.5	$ (15.6)		$ 1,149.3	$ (59.6)