Postretirement Plans (Narrative) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 29, 2012	Dec. 31, 2011	Dec. 29, 2012 Voluntary Employees Beneficiary Association Plan Assets [Member]	Dec. 29, 2007 Voluntary Employees Beneficiary Association Plan Assets [Member]	Dec. 29, 2012 U.S. Postretirement Health Care Plans [Member]	Dec. 31, 2011 U.S. Postretirement Health Care Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 87.5	$ 61.0		$ 14.5	$ 5.3	$ 5.8
Weighted average discount rate snap-on's postretirement plans calculated under previous methodology					2.70%
Accumulated postretirement benefit obligation increase calculated under previous methodology					2.3
Health care cost trend rate, 2013			7.40%
Health care cost trend rate, 2028			4.50%
Increase in accumulated postretirement benefit obligation			1.3
Increase in service cost and interest cost components			0.1
Decrease in accumulated postretirement benefit obligation			1.1
Decrease in service cost and interest cost components			$ 0.1
Description of basis used to determine overall expected long-term, rate-of-return-on-assets assumption			The objective of the VEBA trust is to achieve net of expense returns that meet or exceed the 7.8% long-term, rate-of-return-on-assets assumption used for reporting purposes.