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		6 Months Ended
	Jun. 29, 2013	Jun. 30, 2012	Jun. 29, 2013	Jun. 30, 2012
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 1,963.7	$ 941.5	$ 3,738.2	$ 1,799.7
Cost of goods sold	1,296.3	629.4	2,547.0	1,206.9
Gross profit	667.4	312.1	1,191.2	592.8
Selling, general and administrative	409.4	172.0	825.4	345.4
Research and development	32.1	20.8	65.6	41.6
Operating income (loss)	225.9	119.3	300.2	205.8
Income (Loss) from Equity Method Investments	(0.9)	(0.6)	(1.1)	(1.7)
Other (income) expense:
Gain on sale of business	0	0	(16.7)	0
Net interest expense	18.4	16.1	35.4	30.9
Income before income taxes and noncontrolling interest	208.4	103.8	282.6	176.6
Provision for income taxes	53.0	29.4	73.9	39.1
Noncontrolling interest	1.3	1.7	2.9	3.0
Net income (loss) attributable to Pentair Ltd.	154.1	72.7	205.8	134.5
Comprehensive income (loss), net of tax
Net income	155.4	74.4	208.7	137.5
Changes in cumulative translation adjustment	(41.2)	(85.3)	(118.2)	(45.0)
Changes in market value of derivative financial instruments	(0.4)		0.3
Total comprehensive income (loss)	113.8	(9.6)	90.8	95.6
Less: Comprehensive income (loss) attributable to noncontrolling interest	1.8	(0.2)	2.4	2.0
Comprehensive income (loss) attributable to Pentair Ltd.	112.0	(9.4)	88.4	93.6
Parent Company Guarantor
Condensed Financial Statements, Captions [Line Items]
Selling, general and administrative	0.3		(0.7)
Operating income (loss)	(0.3)		0.7
Loss (earnings) from investment in subsidiaries	(157.1)		(207.8)
Other (income) expense:
Net interest expense	2.7		3.0
Income before income taxes and noncontrolling interest	154.1		205.5
Provision for income taxes			(0.3)
Net income (loss) attributable to Pentair Ltd.	154.1		205.8
Comprehensive income (loss), net of tax
Net income	154.1		205.8
Changes in cumulative translation adjustment	(41.7)		(117.7)
Changes in market value of derivative financial instruments	(0.4)		0.3
Total comprehensive income (loss)	112.0		88.4
Comprehensive income (loss) attributable to Pentair Ltd.	112.0		88.4
Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Selling, general and administrative	3.4		7.0
Operating income (loss)	(3.4)		(7.0)
Loss (earnings) from investment in subsidiaries	(164.1)		(219.0)
Other (income) expense:
Net interest expense	3.5		6.1
Income before income taxes and noncontrolling interest	157.2		205.9
Net income (loss) attributable to Pentair Ltd.	157.2		205.9
Comprehensive income (loss), net of tax
Net income	157.2		205.9
Changes in cumulative translation adjustment	(41.7)		(117.7)
Changes in market value of derivative financial instruments	(0.4)		0.3
Total comprehensive income (loss)	115.1		88.5
Comprehensive income (loss) attributable to Pentair Ltd.	115.1		88.5
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	1,963.7		3,738.2
Cost of goods sold	1,296.3		2,547.0
Gross profit	667.4		1,191.2
Selling, general and administrative	405.7		819.1
Research and development	32.1		65.6
Operating income (loss)	229.6		306.5
Income (Loss) from Equity Method Investments	(0.9)		(1.1)
Other (income) expense:
Gain on sale of business			(16.7)
Net interest expense	12.2		26.3
Income before income taxes and noncontrolling interest	218.3		298.0
Provision for income taxes	53.0		74.2
Noncontrolling interest	1.3		2.9
Net income (loss) attributable to Pentair Ltd.	164.0		220.9
Comprehensive income (loss), net of tax
Net income	165.3		223.8
Changes in cumulative translation adjustment	(41.2)		(118.2)
Changes in market value of derivative financial instruments	(0.4)		0.3
Total comprehensive income (loss)	123.7		105.9
Less: Comprehensive income (loss) attributable to noncontrolling interest	1.8		2.4
Comprehensive income (loss) attributable to Pentair Ltd.	121.9		103.5
Eliminations
Condensed Financial Statements, Captions [Line Items]
Loss (earnings) from investment in subsidiaries	321.2		426.8
Other (income) expense:
Income before income taxes and noncontrolling interest	(321.2)		(426.8)
Net income (loss) attributable to Pentair Ltd.	(321.2)		(426.8)
Comprehensive income (loss), net of tax
Net income	(321.2)		(426.8)
Changes in cumulative translation adjustment	83.4		235.4
Changes in market value of derivative financial instruments	0.8		(0.6)
Total comprehensive income (loss)	(237.0)		(192.0)
Comprehensive income (loss) attributable to Pentair Ltd.	$ (237.0)		$ (192.0)