Segments - Net Sales by Segment (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Total revenues	$ 1,035.4	$ 1,036.6	$ 2,042.7	$ 2,055.1
Operating earnings	250.5	250.9	500.0	485.5
Interest expense	(12.4)	(12.0)	(24.9)	(25.6)
Other income (expense) – net	2.1	(0.6)	3.6	2.2
Earnings before income taxes and equity earnings	240.2	238.3	478.7	462.1
Commercial & Industrial Group
Segment Reporting Information [Line Items]
Total revenues	335.0	337.8	657.5	669.4
Snap-on Tools Group
Segment Reporting Information [Line Items]
Total revenues	405.8	411.9	816.0	816.6
Repair Systems & Information Group
Segment Reporting Information [Line Items]
Total revenues	348.9	343.1	676.8	680.1
Financial Services
Segment Reporting Information [Line Items]
Total revenues	84.1	82.0	169.7	165.0
Operating Segments
Segment Reporting Information [Line Items]
Total revenues	1,089.7	1,092.8	2,150.3	2,166.1
Operating earnings	269.4	274.5	528.8	532.6
Operating Segments \| Commercial & Industrial Group
Segment Reporting Information [Line Items]
Total revenues	335.0	337.8	657.5	669.4
Operating earnings	48.9	49.0	95.4	95.5
Operating Segments \| Snap-on Tools Group
Segment Reporting Information [Line Items]
Total revenues	405.8	411.9	816.0	816.6
Operating earnings	71.3	79.0	138.5	147.9
Operating Segments \| Repair Systems & Information Group
Segment Reporting Information [Line Items]
Total revenues	348.9	343.1	676.8	680.1
Operating earnings	88.6	88.7	172.2	174.5
Operating Segments \| Financial Services
Segment Reporting Information [Line Items]
Operating earnings	60.6	57.8	122.7	114.7
Intersegment eliminations
Segment Reporting Information [Line Items]
Total revenues	(138.4)	(138.2)	(277.3)	(276.0)
Corporate
Segment Reporting Information [Line Items]
Operating earnings	(18.9)	(23.6)	(28.8)	(47.1)
Excluding Financial Services
Segment Reporting Information [Line Items]
Total revenues	951.3	954.6	1,873.0	1,890.1
Operating earnings	189.9	193.1	377.3	370.8
Excluding Financial Services \| Commercial & Industrial Group
Segment Reporting Information [Line Items]
Total revenues	263.0	267.1	512.5	525.9
Excluding Financial Services \| Snap-on Tools Group
Segment Reporting Information [Line Items]
Total revenues	405.8	411.9	816.0	816.6
Excluding Financial Services \| Repair Systems & Information Group
Segment Reporting Information [Line Items]
Total revenues	282.5	275.6	544.5	547.6
Excluding Financial Services \| Financial Services
Segment Reporting Information [Line Items]
Total revenues	0.0	0.0	0.0	0.0
Excluding Financial Services \| Operating Segments
Segment Reporting Information [Line Items]
Total revenues	951.3	954.6	1,873.0	1,890.1
Excluding Financial Services \| Operating Segments \| Commercial & Industrial Group
Segment Reporting Information [Line Items]
Total revenues	335.0	337.8	657.5	669.4
Excluding Financial Services \| Operating Segments \| Snap-on Tools Group
Segment Reporting Information [Line Items]
Total revenues	405.8	411.9	816.0	816.6
Excluding Financial Services \| Operating Segments \| Repair Systems & Information Group
Segment Reporting Information [Line Items]
Total revenues	348.9	343.1	676.8	680.1
Excluding Financial Services \| Operating Segments \| Financial Services
Segment Reporting Information [Line Items]
Total revenues	0.0	0.0	0.0	0.0
Excluding Financial Services \| Intersegment eliminations
Segment Reporting Information [Line Items]
Total revenues	(138.4)	(138.2)	(277.3)	(276.0)
Excluding Financial Services \| Intersegment eliminations \| Commercial & Industrial Group
Segment Reporting Information [Line Items]
Total revenues	72.0	70.7	145.0	143.5
Excluding Financial Services \| Intersegment eliminations \| Snap-on Tools Group
Segment Reporting Information [Line Items]
Total revenues	0.0	0.0	0.0	0.0
Excluding Financial Services \| Intersegment eliminations \| Repair Systems & Information Group
Segment Reporting Information [Line Items]
Total revenues	66.4	67.5	132.3	132.5
Excluding Financial Services \| Intersegment eliminations \| Financial Services
Segment Reporting Information [Line Items]
Total revenues	0.0	0.0	0.0	0.0
Financial Service
Segment Reporting Information [Line Items]
Total revenues	84.1	82.0	169.7	165.0
Operating earnings	60.6	57.8	122.7	114.7
Financial Service \| Commercial & Industrial Group
Segment Reporting Information [Line Items]
Total revenues	0.0	0.0	0.0	0.0
Financial Service \| Snap-on Tools Group
Segment Reporting Information [Line Items]
Total revenues	0.0	0.0	0.0	0.0
Financial Service \| Repair Systems & Information Group
Segment Reporting Information [Line Items]
Total revenues	0.0	0.0	0.0	0.0
Financial Service \| Financial Services
Segment Reporting Information [Line Items]
Total revenues	84.1	82.0	169.7	165.0
Financial Service \| Intersegment eliminations
Segment Reporting Information [Line Items]
Total revenues	$ 0.0	$ 0.0	$ 0.0	$ 0.0

Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

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