Financial Statements of Parent Company Guarantor - Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 28, 2015
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 1,575.5	$ 1,475.0
Cost of goods sold	1,040.1	964.8
Gross profit	(535.4)	(510.2)
Selling, general and administrative	331.6	309.2
Research and development	33.2	29.8
Operating Income (Loss)	170.6	171.2
Income (Loss) from Equity Method Investments	(0.9)	(0.5)
Other (income) expense:
Net interest expense	36.4	18.2
Income from continuing operations before income taxes	135.1	153.5
Provision for income taxes	27.7	35.3
Net Income (Loss) from Continuing Operations	107.4	118.2
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0.0	4.3
Net income (loss) attributable to Pentair plc	107.4	113.9
Income (Loss) from Continuing Operations Attributable to Parent	107.4	118.2
Comprehensive income (loss), net of tax
Net income	107.4	113.9
Changes in cumulative translation adjustment	(28.0)	174.2
Changes in market value of derivative financial instruments	(14.7)	(0.1)
Comprehensive income (loss) attributable to Pentair plc	120.7	(60.4)
Parent Company Guarantor
Condensed Financial Statements, Captions [Line Items]
Gross profit	0.0
Selling, general and administrative	8.4	3.1
Operating Income (Loss)	(8.4)	(3.1)
Other (income) expense:
Net interest expense	0.0	0.0
Income from continuing operations before income taxes	107.4	117.6
Provision for income taxes	0.0	(0.6)
Net Income (Loss) from Continuing Operations		118.2
Net income (loss) attributable to Pentair plc	107.4	113.9
Comprehensive income (loss), net of tax
Net income	107.4	113.9
Changes in cumulative translation adjustment	(28.0)	174.2
Changes in market value of derivative financial instruments	(14.7)	(0.1)
Comprehensive income (loss) attributable to Pentair plc	120.7	(60.4)
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Gross profit	0.0
Selling, general and administrative	0.0	0.1
Operating Income (Loss)	0.0	(0.1)
Other (income) expense:
Net interest expense	0.0	0.9
Income from continuing operations before income taxes	115.8	120.7
Provision for income taxes	0.0	0.0
Net Income (Loss) from Continuing Operations		120.7
Net income (loss) attributable to Pentair plc	115.8	116.4
Comprehensive income (loss), net of tax
Net income	115.8	116.4
Changes in cumulative translation adjustment	(28.0)	174.2
Changes in market value of derivative financial instruments	(14.7)	(0.1)
Comprehensive income (loss) attributable to Pentair plc	129.1	(57.9)
Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Gross profit	0.0
Selling, general and administrative	0.9	1.1
Operating Income (Loss)	(0.9)	(1.1)
Other (income) expense:
Net interest expense	27.4	3.5
Income from continuing operations before income taxes	115.8	113.9
Provision for income taxes	0.0	0.0
Net Income (Loss) from Continuing Operations		113.9
Net income (loss) attributable to Pentair plc	115.8	109.6
Comprehensive income (loss), net of tax
Net income	109.4	109.6
Changes in cumulative translation adjustment	(28.0)	174.2
Changes in market value of derivative financial instruments	(14.7)	(0.1)
Comprehensive income (loss) attributable to Pentair plc	122.7	(64.7)
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	1,575.5	1,475.0
Cost of goods sold	1,040.1	964.8
Gross profit	(535.4)	(510.2)
Selling, general and administrative	322.3	304.9
Research and development	33.2	29.8
Operating Income (Loss)	179.9	175.5
Income (Loss) from Equity Method Investments	(0.9)	(0.5)
Other (income) expense:
Net interest expense	9.0	13.8
Income from continuing operations before income taxes	171.8	162.2
Provision for income taxes	27.7	35.9
Net Income (Loss) from Continuing Operations		126.3
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent		4.3
Net income (loss) attributable to Pentair plc	144.1	122.0
Comprehensive income (loss), net of tax
Net income	137.7	122.0
Changes in cumulative translation adjustment	(28.0)	174.2
Changes in market value of derivative financial instruments	(14.7)	(0.1)
Comprehensive income (loss) attributable to Pentair plc	151.0	(52.3)
Eliminations
Other (income) expense:
Income from continuing operations before income taxes	(375.7)	(360.9)
Net Income (Loss) from Continuing Operations		(360.9)
Net income (loss) attributable to Pentair plc	(375.7)	(348.0)
Comprehensive income (loss), net of tax
Net income	(362.9)	(348.0)
Changes in cumulative translation adjustment	84.0	(522.6)
Changes in market value of derivative financial instruments	44.1	0.3
Comprehensive income (loss) attributable to Pentair plc	(402.8)	174.9
Continuing Operations [Member] | Parent Company Guarantor
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	115.8	120.7
Continuing Operations [Member] | Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	115.8	121.7
Continuing Operations [Member] | Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	144.1	118.5
Continuing Operations [Member] | Eliminations
Condensed Financial Statements, Captions [Line Items]
Gross profit	0.0
Loss (earnings) from investment in subsidiaries	$ (375.7)	(360.9)
Discontinued Operations [Member] | Parent Company Guarantor
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries		4.3
Discontinued Operations [Member] | Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries		4.3
Discontinued Operations [Member] | Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries		4.3
Discontinued Operations [Member] | Eliminations
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries		$ (12.9)