Selected Quarterly Data - Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ 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
Quarterly Financial Information [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
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
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
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)
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
Income (Loss) from Continuing Operations, Per Basic Share	$ (2.51)		$ 0.64		$ 0.85		$ 0.66		$ 0.71		$ 1.01		$ 0.82		$ 0.64		$ (0.36)		$ 3.19		$ 2.54
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	(0.01)		0.00		(0.03)		(0.03)		(0.05)		(1.99)		0.02		(0.04)		(0.06)		(2.06)		0.13
Earnings (loss) per ordinary share attributable to Pentair plc
Earnings Per Share, Basic	(2.52)	[1]	0.64	[1]	0.82	[1]	0.63	[1]	0.66	[1]	(0.98)	[1]	0.84	[1]	0.60	[1]	(0.42)	[1]	1.13	[1]	2.67
Income (Loss) from Continuing Operations, Per Diluted Share	(2.51)		0.63		0.84		0.65		0.70		1.00		0.81		0.63		(0.36)		3.14		2.50
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	(0.01)		0.00		(0.03)		(0.03)		(0.05)		(1.95)		0.01		(0.04)		(0.06)		(2.03)		0.12
Diluted	$ (2.52)	[1]	$ 0.63	[1]	$ 0.81	[1]	$ 0.62	[1]	$ 0.65	[1]	$ (0.95)	[1]	$ 0.82	[1]	$ 0.59	[1]	$ (0.42)	[1]	$ 1.11	[1]	$ 2.62

[1] Amounts may not total to annual earnings because each quarter and year are calculated separately based on basic and diluted weighted-average ordinary shares outstanding during that period