Segments - Net Sales by Segment (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
Segment Reporting Information [Line Items]
Net sales	$ 753.2	$ 711.6	$ 2,259.0	$ 2,184.7
Financial services revenue	45.1	40.5	133.6	118.4
Total revenues	798.3	752.1	2,392.6	2,303.1
Operating earnings	142.9	124.1	429.6	375.7
Interest expense	(14.4)	(13.6)	(41.8)	(41.4)
Other income (expense) - net	(0.8)	(0.2)	(3.1)	(0.5)
Earnings before income taxes and equity earnings	127.7	110.3	384.7	333.8
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	861.7	811.2	2,560.1	2,476.2
Operating earnings	167.4	151.0	507.6	453.9
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	(108.5)	(99.6)	(301.1)	(291.5)
Corporate [Member]
Segment Reporting Information [Line Items]
Operating earnings	(24.5)	(26.9)	(78.0)	(78.2)
Commercial & Industrial Group [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	275.2	280.4	807.8	850.3
Operating earnings	36.0	33.4	100.2	95.4
Snap-on Tools Group [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	333.8	308.8	1,007.3	950.4
Operating earnings	41.9	40.2	143.6	130.8
Repair Systems & Information Group [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	252.7	222.0	745.0	675.5
Operating earnings	57.9	49.5	171.1	150.3
Financial Services [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating earnings	$ 31.6	$ 27.9	$ 92.7	$ 77.4