Financial Statements of Parent Company Guarantor - Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Net Income (Loss) Attributable to Parent	$ 87.8	$ 107.4
Net sales	1,183.5	1,190.0
Cost of goods sold	761.2	758.7
Gross profit	422.3	431.3
Selling, general and administrative	253.9	250.1
Research and development	30.0	28.5
Operating Income (Loss)	138.4	152.7
Other (income) expense:
Equity income of unconsolidated subsidiaries	(0.2)	(0.4)
Net interest expense	35.0	36.2
Income from continuing operations before income taxes	103.6	116.9
Provision for income taxes	22.9	25.1
Net Income (Loss) from Continuing Operations	80.7	91.8
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(7.1)	(15.6)
Comprehensive income, net of tax
Net income	87.8	107.4
Changes in cumulative translation adjustment	(75.7)	(28.0)
Changes in market value of derivative financial instruments	1.6	(14.7)
Comprehensive income (loss) attributable to Pentair plc	165.1	120.7
Parent Company Guarantor
Condensed Financial Statements, Captions [Line Items]
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	7.1	15.6
Net Income (Loss) Attributable to Parent		107.4
Selling, general and administrative	(11.0)	7.2
Research and development	0.0
Operating Income (Loss)	11.0	(7.2)
Loss (earnings) from investment in subsidiaries	(69.7)	(99.0)
Other (income) expense:
Net interest expense	0.0	0.0
Income from continuing operations before income taxes	80.7	91.8
Provision for income taxes	0.0	0.0
Net Income (Loss) from Continuing Operations	80.7	91.8
Comprehensive income, net of tax
Net income	87.8	107.4
Changes in cumulative translation adjustment	(75.7)	(28.0)
Changes in market value of derivative financial instruments	1.6	(14.7)
Comprehensive income (loss) attributable to Pentair plc	165.1	120.7
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	7.1	15.6
Net Income (Loss) Attributable to Parent		114.6
Selling, general and administrative	0.1	0.0
Operating Income (Loss)	(0.1)	0.0
Loss (earnings) from investment in subsidiaries	(69.7)	(99.0)
Other (income) expense:
Net interest expense	(0.1)	0.0
Income from continuing operations before income taxes	69.7	99.0
Provision for income taxes	0.0	0.0
Net Income (Loss) from Continuing Operations	69.7	99.0
Comprehensive income, net of tax
Net income	76.8	114.6
Changes in cumulative translation adjustment	(75.7)	(28.0)
Changes in market value of derivative financial instruments	1.6	(14.7)
Comprehensive income (loss) attributable to Pentair plc	154.1	127.9
Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	7.1	15.6
Net Income (Loss) Attributable to Parent		114.6
Selling, general and administrative	0.4	0.9
Operating Income (Loss)	(0.4)	(0.9)
Loss (earnings) from investment in subsidiaries	(98.5)	(127.3)
Other (income) expense:
Net interest expense	28.4	27.4
Income from continuing operations before income taxes	69.7	99.0
Provision for income taxes	0.0	0.0
Net Income (Loss) from Continuing Operations	69.7	99.0
Comprehensive income, net of tax
Net income	76.8	114.6
Changes in cumulative translation adjustment	(75.7)	(28.0)
Changes in market value of derivative financial instruments	1.6	(14.7)
Comprehensive income (loss) attributable to Pentair plc	154.1	127.9
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net Income (Loss) Attributable to Parent		142.9
Net sales	1,183.5	1,190.0
Cost of goods sold	761.2	758.7
Gross profit	422.3	431.3
Selling, general and administrative	264.4	242.0
Research and development	30.0	28.5
Operating Income (Loss)	127.9	160.8
Other (income) expense:
Equity income of unconsolidated subsidiaries	(0.2)	(0.4)
Net interest expense	6.7	8.8
Income from continuing operations before income taxes	121.4	152.4
Provision for income taxes	22.9	25.1
Net Income (Loss) from Continuing Operations	98.5	127.3
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(7.1)	(15.6)
Comprehensive income, net of tax
Net income	105.6	142.9
Changes in cumulative translation adjustment	(75.7)	(28.0)
Changes in market value of derivative financial instruments	1.6	(14.7)
Comprehensive income (loss) attributable to Pentair plc	182.9	156.2
Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Discontinued Operation, Income (Loss) from Investment in Subsidiaries	(21.3)	(46.8)
Net Income (Loss) Attributable to Parent		(372.1)
Loss (earnings) from investment in subsidiaries	237.9	325.3
Other (income) expense:
Income from continuing operations before income taxes	(237.9)	(325.3)
Net Income (Loss) from Continuing Operations	(237.9)	(325.3)
Comprehensive income, net of tax
Net income	(259.2)	(372.1)
Changes in cumulative translation adjustment	227.1	84.0
Changes in market value of derivative financial instruments	(4.8)	44.1
Comprehensive income (loss) attributable to Pentair plc	$ (491.1)	$ (412.0)