Income Taxes - Narrative (Detail) - USD ($)	9 Months Ended
Sep. 26, 2020	Sep. 28, 2019
Income Tax [Line Items]
Effective income tax rate	23.80%	23.80%
Minimum
Income Tax [Line Items]
Decrease in unrecognized tax benefits	$ 0
Increase in unrecognized tax benefits	0
Maximum
Income Tax [Line Items]
Decrease in unrecognized tax benefits	700,000
Increase in unrecognized tax benefits	$ 800,000

Effective income tax rate on earnings attributable to Snap-on.

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- Definition

Income Tax [Line Items]

+ References

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- Definition

Amount of decrease reasonably possible in the next twelve months for the unrecognized tax benefit.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (d)(3)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319

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- Definition

Amount of increase reasonably possible in the next twelve months for the unrecognized tax benefit.

+ References

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