Financial Statements of Parent Company Guarantor - Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 26, 2015	Jun. 27, 2015	Mar. 28, 2015	Dec. 31, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 1,760.7	$ 1,552.1	$ 1,661.2	$ 1,475.0	$ 1,802.5	$ 1,758.4	$ 1,834.1	$ 1,644.0	$ 6,449.0	$ 7,039.0	$ 6,999.7
Cost of goods sold									4,263.2	4,576.0	4,629.6
Gross profit	569.3	540.1	566.2	510.2	627.9	624.7	646.3	564.1	2,185.8	2,463.0	2,370.1
Selling, general and administrative									1,334.3	1,493.8	1,493.7
Research and development									119.6	117.3	122.8
Impairment of goodwill and trade names									554.7	0.0	11.0
Operating income (loss)	(391.9)	180.0	217.9	171.2	176.0	267.4	226.4	182.1	177.2	851.9	742.6
Loss (earnings) from investment in subsidiaries									0.0	0.0	0.0
Loss (gain) on sale of businesses, net									3.2	0.2	(20.8)
Other (income) expense:
Equity income of unconsolidated subsidiaries									(2.8)	(1.2)	(2.0)
Interest income									(6.0)	(3.7)	(4.4)
Interest expense									108.7	72.3	75.3
Income (loss) from continuing operations before income taxes and noncontrolling interest									74.1	784.3	694.5
Provision for income taxes									139.1	177.3	177.0
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	(452.3)	115.2	153.9	118.2	129.8	192.5	159.2	125.5	(65.0)	607.0	517.5
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, Net of Tax	0.9	0.0	(1.3)	(4.3)	(9.0)	1.6	2.3	(1.3)	(4.7)	(6.4)	25.9
Discontinued Operation, Provision for Loss (Gain) on Disposal, Net of Tax	1.9	0.0	(4.8)	0.0	0.0	(380.1)	0.0	(5.6)	(6.7)	(385.7)	(0.8)
Discontinued Operation, Income (Loss) from Investment in Subsidiaries									0.0	0.0	0.0
Net income (loss) from continuing operations before noncontrolling interest									(76.4)	214.9	542.6
Noncontrolling interest									0.0	0.0	5.8
Net income (loss) attributable to Pentair plc	$ (453.3)	$ 115.2	$ 147.8	$ 113.9	$ 120.8	$ (186.0)	$ 161.5	$ 118.6	(76.4)	214.9	536.8
Income (Loss) from Continuing Operations Attributable to Pentair plc									(65.0)	607.0	511.7
Comprehensive income (loss), net of tax
Net income (loss) before noncontrolling interest									(76.4)	214.9	542.6
Changes in cumulative translation adjustment									(264.9)	(336.3)	(29.1)
Amortization of pension and other post-retirement prior service cost									0.0	0.0	(0.4)
Changes in market value of derivative financial instruments									0.2	(0.4)	(0.3)
Total comprehensive income (loss)									(341.1)	(121.8)	512.8
Less: Comprehensive income attributable to noncontrolling interest									0.0	0.0	8.0
Comprehensive income (loss) attributable to Pentair plc									(341.1)	(121.8)	504.8
Parent Company Guarantor
Condensed Financial Statements, Captions [Line Items]
Net sales									0.0	0.0	0.0
Cost of goods sold									0.0	0.0	0.0
Gross profit									0.0	0.0	0.0
Selling, general and administrative									33.7	25.3	21.0
Research and development									0.0	0.0	0.0
Impairment of goodwill and trade names									0.0		0.0
Operating income (loss)									(33.7)	(25.3)	(21.0)
Loss (earnings) from investment in subsidiaries									26.0	(615.5)	(539.0)
Loss (gain) on sale of businesses, net									0.0	0.0
Other (income) expense:
Equity income of unconsolidated subsidiaries									0.0	0.0	0.0
Interest income									0.0	0.0	0.0
Interest expense									0.0	0.7	5.6
Income (loss) from continuing operations before income taxes and noncontrolling interest									(59.7)	589.5	512.4
Provision for income taxes									5.3	(17.5)	0.7
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest									(65.0)	607.0	511.7
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, Net of Tax									0.0	0.0	0.0
Discontinued Operation, Provision for Loss (Gain) on Disposal, Net of Tax									0.0	0.0	0.0
Discontinued Operation, Income (Loss) from Investment in Subsidiaries									(11.4)	(392.1)	25.1
Net income (loss) from continuing operations before noncontrolling interest											536.8
Noncontrolling interest											0.0
Net income (loss) attributable to Pentair plc									(76.4)	214.9	536.8
Income (Loss) from Continuing Operations Attributable to Pentair plc											511.7
Comprehensive income (loss), net of tax
Net income (loss) before noncontrolling interest									(76.4)	214.9	536.8
Changes in cumulative translation adjustment									(264.9)	(336.3)	(31.3)
Amortization of pension and other post-retirement prior service cost											(0.4)
Changes in market value of derivative financial instruments									0.2	(0.4)	(0.3)
Total comprehensive income (loss)											504.8
Less: Comprehensive income attributable to noncontrolling interest											0.0
Comprehensive income (loss) attributable to Pentair plc									(341.1)	(121.8)	504.8
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net sales									0.0	0.0
Cost of goods sold									0.0	0.0
Gross profit									0.0	0.0
Selling, general and administrative									2.2	2.6
Research and development									0.0	0.0
Impairment of goodwill and trade names									0.0
Operating income (loss)									(2.2)	(2.6)
Loss (earnings) from investment in subsidiaries									22.4	(619.7)
Loss (gain) on sale of businesses, net									0.0	0.0
Other (income) expense:
Equity income of unconsolidated subsidiaries									0.0	0.0
Interest income									0.0	0.0
Interest expense									1.4	2.1
Income (loss) from continuing operations before income taxes and noncontrolling interest									(26.0)	615.0
Provision for income taxes									0.0	(0.5)
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest									(26.0)	615.5
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, Net of Tax									0.0	0.0
Discontinued Operation, Provision for Loss (Gain) on Disposal, Net of Tax									0.0	0.0
Discontinued Operation, Income (Loss) from Investment in Subsidiaries									(11.4)	(392.1)
Net income (loss) attributable to Pentair plc									(37.4)	223.4
Comprehensive income (loss), net of tax
Net income (loss) before noncontrolling interest									(37.4)	223.4
Changes in cumulative translation adjustment									(264.9)	(336.3)
Changes in market value of derivative financial instruments									0.2	(0.4)
Comprehensive income (loss) attributable to Pentair plc									(302.1)	(113.3)
Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Net sales									0.0	0.0	0.0
Cost of goods sold									0.0	0.0	0.0
Gross profit									0.0	0.0	0.0
Selling, general and administrative									5.3	7.7	13.3
Research and development									0.0	0.0	0.0
Impairment of goodwill and trade names									0.0		0.0
Operating income (loss)									(5.3)	(7.7)	(13.3)
Loss (earnings) from investment in subsidiaries									(13.0)	(611.1)	(508.6)
Loss (gain) on sale of businesses, net									0.0	0.0
Other (income) expense:
Equity income of unconsolidated subsidiaries									0.0	0.0	0.0
Interest income									(80.6)	(92.3)	(99.2)
Interest expense									126.3	95.6	106.0
Income (loss) from continuing operations before income taxes and noncontrolling interest									(38.0)	600.1	488.5
Provision for income taxes									0.0	(2.4)	1.4
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest									(38.0)	602.5	487.1
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, Net of Tax									0.0	0.0	0.0
Discontinued Operation, Provision for Loss (Gain) on Disposal, Net of Tax									0.0	0.0	0.0
Discontinued Operation, Income (Loss) from Investment in Subsidiaries									(11.4)	(392.1)	25.1
Net income (loss) from continuing operations before noncontrolling interest											512.2
Noncontrolling interest											0.0
Net income (loss) attributable to Pentair plc									(49.4)	210.4	512.2
Income (Loss) from Continuing Operations Attributable to Pentair plc											487.1
Comprehensive income (loss), net of tax
Net income (loss) before noncontrolling interest									(49.4)	210.4	512.2
Changes in cumulative translation adjustment									(264.9)	(336.3)	(31.3)
Amortization of pension and other post-retirement prior service cost											(0.4)
Changes in market value of derivative financial instruments									0.2	(0.4)	(0.3)
Total comprehensive income (loss)											480.2
Less: Comprehensive income attributable to noncontrolling interest											0.0
Comprehensive income (loss) attributable to Pentair plc									(314.1)	(126.3)	480.2
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales									6,449.0	7,039.0	6,999.7
Cost of goods sold									4,263.2	4,576.0	4,629.6
Gross profit									2,185.8	2,463.0	2,370.1
Selling, general and administrative									1,293.1	1,458.2	1,459.4
Research and development									119.6	117.3	122.8
Impairment of goodwill and trade names									554.7		11.0
Operating income (loss)									218.4	887.5	776.9
Loss (earnings) from investment in subsidiaries									0.0	0.0	0.0
Loss (gain) on sale of businesses, net									3.2	0.2	(20.8)
Other (income) expense:
Equity income of unconsolidated subsidiaries									(2.8)	(1.2)	(2.0)
Interest income									(35.1)	(40.2)	(53.4)
Interest expense									90.7	102.7	111.9
Income (loss) from continuing operations before income taxes and noncontrolling interest									162.4	826.0	741.2
Provision for income taxes									133.8	197.7	174.9
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest									28.6	628.3	566.3
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, Net of Tax									(4.7)	(6.4)	25.9
Discontinued Operation, Provision for Loss (Gain) on Disposal, Net of Tax									(6.7)	(385.7)	(0.8)
Discontinued Operation, Income (Loss) from Investment in Subsidiaries									0.0	0.0	0.0
Net income (loss) from continuing operations before noncontrolling interest											591.4
Noncontrolling interest											5.8
Net income (loss) attributable to Pentair plc									17.2	236.2	585.6
Income (Loss) from Continuing Operations Attributable to Pentair plc											560.5
Comprehensive income (loss), net of tax
Net income (loss) before noncontrolling interest									17.2	236.2	591.4
Changes in cumulative translation adjustment									(264.9)	(336.3)	(29.1)
Amortization of pension and other post-retirement prior service cost											(0.4)
Changes in market value of derivative financial instruments									0.2	(0.4)	(0.3)
Total comprehensive income (loss)											561.6
Less: Comprehensive income attributable to noncontrolling interest											8.0
Comprehensive income (loss) attributable to Pentair plc									(247.5)	(100.5)	553.6
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net sales									0.0	0.0	0.0
Cost of goods sold									0.0	0.0	0.0
Gross profit									$ 0.0	0.0	0.0
Selling, general and administrative										0.0	0.0
Research and development									$ 0.0	0.0	0.0
Impairment of goodwill and trade names									0.0		0.0
Operating income (loss)									0.0	0.0	0.0
Loss (earnings) from investment in subsidiaries									(35.4)	1,846.3	1,047.6
Loss (gain) on sale of businesses, net									0.0	0.0
Other (income) expense:
Equity income of unconsolidated subsidiaries									0.0	0.0	0.0
Interest income									109.7	128.8	148.2
Interest expense									(109.7)	(128.8)	(148.2)
Income (loss) from continuing operations before income taxes and noncontrolling interest									35.4	(1,846.3)	(1,047.6)
Provision for income taxes									0.0	0.0	0.0
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest									35.4	(1,846.3)	(1,047.6)
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, Net of Tax									0.0	0.0	0.0
Discontinued Operation, Provision for Loss (Gain) on Disposal, Net of Tax									0.0	0.0	0.0
Discontinued Operation, Income (Loss) from Investment in Subsidiaries									34.2	1,176.3	(50.2)
Net income (loss) from continuing operations before noncontrolling interest											(1,097.8)
Noncontrolling interest											0.0
Net income (loss) attributable to Pentair plc									69.6	(670.0)	(1,097.8)
Income (Loss) from Continuing Operations Attributable to Pentair plc											(1,047.6)
Comprehensive income (loss), net of tax
Net income (loss) before noncontrolling interest									69.6	(670.0)	(1,097.8)
Changes in cumulative translation adjustment									794.7	1,008.9	62.6
Amortization of pension and other post-retirement prior service cost											0.8
Changes in market value of derivative financial instruments									(0.6)	1.2	0.6
Total comprehensive income (loss)											(1,033.8)
Less: Comprehensive income attributable to noncontrolling interest											0.0
Comprehensive income (loss) attributable to Pentair plc									$ 863.7	$ 340.1	$ (1,033.8)