Segments - Net Sales by Segment (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2016	Oct. 03, 2015	Oct. 01, 2016	Oct. 03, 2015
Segment Reporting Information [Line Items]
Net sales	$ 834.1	$ 821.5	$ 2,540.6	$ 2,501.1
Financial services revenue	71.6	61.1	207.2	177.2
Total revenues	905.7	882.6	2,747.8	2,678.3
Operating earnings	208.2	187.1	626.5	557.5
Interest expense	(13.1)	(13.0)	(39.1)	(38.9)
Other income (expense) - net	(0.8)	(0.5)	(0.3)	(1.9)
Earnings before income taxes and equity earnings	194.3	173.6	587.1	516.7
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	972.6	952.0	2,938.5	2,871.9
Operating earnings	230.7	210.8	694.1	638.1
Operating Segments [Member] | Commercial & Industrial Group [Member]
Segment Reporting Information [Line Items]
Net sales	289.3	288.5	862.0	881.8
Operating earnings	43.7	41.3	124.1	127.5
Operating Segments [Member] | Snap-on Tools Group [Member]
Segment Reporting Information [Line Items]
Net sales	397.2	380.6	1,216.4	1,157.5
Operating earnings	64.6	56.3	207.6	184.1
Operating Segments [Member] | Repair Systems & Information Group [Member]
Segment Reporting Information [Line Items]
Net sales	286.1	282.9	860.1	832.6
Operating earnings	71.8	69.7	215.3	201.3
Operating Segments [Member] | Financial Services [Member]
Segment Reporting Information [Line Items]
Operating earnings	50.6	43.5	147.1	125.2
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	(138.5)	(130.5)	(397.9)	(370.8)
Corporate [Member]
Segment Reporting Information [Line Items]
Operating earnings	$ (22.5)	$ (23.7)	$ (67.6)	$ (80.6)