Selected Quarterly Data - Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended															12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2015	Sep. 26, 2015		Jun. 27, 2015		Mar. 28, 2015		Sep. 27, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information [Line Items]
(Income) loss from discontinued operations, net of tax																$ 70.0	$ (466.8)	$ 244.0
Net sales	$ 1,188.1	$ 1,210.7		$ 1,301.2		$ 1,190.0		$ 1,289.0	$ 1,112.8		$ 1,167.1		$ 1,047.5			4,890.0	4,616.4	4,666.8
Gross profit	440.1	440.9		481.8		431.3		432.5	394.7		415.3		356.3			1,794.1	1,598.8	1,620.5
Operating income (loss)	161.8	182.8		203.4		152.7		171.7	152.9		170.8		120.7			700.7	616.1	538.5
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	109.6	117.5		132.7		91.8		104.0	94.7		118.4		80.0			451.6	397.1	356.6
Income (loss) from discontinued operations, net of tax	21.4	22.9		10.1		15.6		(555.4)	20.5		34.2		33.9		$ 380.1	70.0	(466.8)	244.0
Gain (loss) from sale / impairment of discontinued operations, net of tax	0.0	0.6		0.0		0.0		(1.9)	0.0		(4.8)		0.0			0.6	(6.7)	(385.7)
Net income (loss) attributable to Pentair plc	$ 131.0	$ 141.0		$ 142.8		$ 107.4		$ (453.3)	$ 115.2		$ 147.8		$ 113.9			$ 522.2	$ (76.4)	$ 214.9
Earnings (loss) per ordinary share
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.60	$ 0.65		$ 0.73		$ 0.50		$ 0.58	$ 0.53		$ 0.66		$ 0.44			$ 2.49	$ 2.20	$ 1.87
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	0.12	0.13		0.06		0.09		(3.10)	0.11		0.16		0.19			0.39	(2.62)	(0.74)
Earnings Per Share, Basic	0.72	0.78	[1]	0.79	[1]	0.59	[1]	(2.52)	0.64	[1]	0.82	[1]	0.63	[1]		2.88	(0.42)	1.13
Income (Loss) from Continuing Operations, Per Diluted Share	0.60	0.64		0.73		0.50		0.58	0.52		0.65		0.44			2.47	2.17	1.84
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	0.11	0.13		0.05		0.09		(3.10)	0.11		0.16		0.18			0.38	(2.59)	(0.73)
Diluted	$ 0.71	$ 0.77	[1]	$ 0.78	[1]	$ 0.59	[1]	$ (2.52)	$ 0.63	[1]	$ 0.81	[1]	$ 0.62	[1]		$ 2.85	$ (0.42)	$ 1.11

[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