Financial Statements of Parent Company Guarantor - Condensed Consolidating Statement of Operations and Comprehensive Income (Loss) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 1,824.8	$ 865.5	$ 5,563.0	$ 2,665.2
Cost of goods sold	1,187.2	587.4	3,734.2	1,794.3
Gross profit	637.6	278.1	1,828.8	870.9
Selling, general and administrative	366.1	203.1	1,191.5	548.5
Research and development	31.5	19.8	97.1	61.4
Operating income (loss)	240.0	55.2	540.2	261.0
Income (Loss) from Equity Method Investments	(0.5)	(0.6)	(1.6)	(2.3)
Other (income) expense:
Gain on sale of business	(0.1)	0	(16.8)	0
Net interest expense	17.2	18.6	52.6	49.5
Income before income taxes and noncontrolling interest	223.4	37.2	506.0	213.8
Provision for income taxes	49.2	4.6	123.1	43.7
Noncontrolling interest	1.4	1.2	4.3	4.2
Net income (loss) attributable to Pentair Ltd.	172.8	31.4	378.6	165.9
Comprehensive income (loss), net of tax
Net income	174.2	32.6	382.9	170.1
Changes in cumulative translation adjustment	89.1	41.2	(29.1)	(3.8)
Changes in market value of derivative financial instruments	(0.6)	(8.4)	(0.3)	(5.3)
Total comprehensive income	262.7	65.4	353.5	161.0
Less: Comprehensive income attributable to noncontrolling interest	2.6	2.1	5.0	4.1
Comprehensive income (loss) attributable to Pentair Ltd.	260.1	63.3	348.5	156.9
Parent Company Guarantor
Condensed Financial Statements, Captions [Line Items]
Selling, general and administrative	(0.7)		(1.5)
Operating income (loss)	0.7		1.5
Loss (earnings) from investment in subsidiaries	(173.3)		(381.1)
Other (income) expense:
Net interest expense	1.3		4.4
Income before income taxes and noncontrolling interest	172.7		378.2
Provision for income taxes	(0.1)		(0.4)
Net income (loss) attributable to Pentair Ltd.	172.8		378.6
Comprehensive income (loss), net of tax
Net income	172.8		378.6
Changes in cumulative translation adjustment	87.9		(29.8)
Changes in market value of derivative financial instruments	(0.6)		(0.3)
Total comprehensive income	260.1		348.5
Comprehensive income (loss) attributable to Pentair Ltd.	260.1		348.5
Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Selling, general and administrative	3.1		10.1
Operating income (loss)	(3.1)		(10.1)
Loss (earnings) from investment in subsidiaries	(177.3)		(396.4)
Other (income) expense:
Net interest expense	0.6		6.7
Income before income taxes and noncontrolling interest	173.6		379.6
Provision for income taxes	1.3		1.3
Net income (loss) attributable to Pentair Ltd.	172.3		378.3
Comprehensive income (loss), net of tax
Net income	172.3		378.3
Changes in cumulative translation adjustment	87.9		(29.8)
Changes in market value of derivative financial instruments	(0.6)		(0.3)
Total comprehensive income	259.6		348.2
Comprehensive income (loss) attributable to Pentair Ltd.	259.6		348.2
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	1,824.8		5,563.0
Cost of goods sold	1,187.2		3,734.2
Gross profit	637.6		1,828.8
Selling, general and administrative	363.7		1,182.9
Research and development	31.5		97.1
Operating income (loss)	242.4		548.8
Income (Loss) from Equity Method Investments	(0.5)		(1.6)
Other (income) expense:
Gain on sale of business	(0.1)		(16.8)
Net interest expense	15.3		41.5
Income before income taxes and noncontrolling interest	227.7		525.7
Provision for income taxes	48.0		122.2
Noncontrolling interest	1.4		4.3
Net income (loss) attributable to Pentair Ltd.	178.3		399.2
Comprehensive income (loss), net of tax
Net income	179.7		403.5
Changes in cumulative translation adjustment	89.1		(29.1)
Changes in market value of derivative financial instruments	(0.6)		(0.3)
Total comprehensive income	268.2		374.1
Less: Comprehensive income attributable to noncontrolling interest	2.6		5.0
Comprehensive income (loss) attributable to Pentair Ltd.	265.6		369.1
Eliminations
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	350.6		777.5
Other (income) expense:
Income before income taxes and noncontrolling interest	(350.6)		(777.5)
Net income (loss) attributable to Pentair Ltd.	(350.6)		(777.5)
Comprehensive income (loss), net of tax
Net income	(350.6)		(777.5)
Changes in cumulative translation adjustment	(175.8)		59.6
Changes in market value of derivative financial instruments	1.2		0.6
Total comprehensive income	(525.2)		(717.3)
Comprehensive income (loss) attributable to Pentair Ltd.	$ (525.2)		$ (717.3)