Goodwill and Other Intangible Assets - Changes in Carrying Amount of Goodwill by Segment (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
Goodwill [Roll Forward]
December 30, 2017	$ 924.1
Currency translation	11.5
Acquisitions and related adjustments	5.8
March 31, 2018	941.4
Commercial & Industrial Group
Goodwill [Roll Forward]
December 30, 2017	298.4
Currency translation	8.3
Acquisitions and related adjustments	5.8
March 31, 2018	312.5
Snap-on Tools Group
Goodwill [Roll Forward]
December 30, 2017	12.5
Currency translation	0.0
Acquisitions and related adjustments	0.0
March 31, 2018	12.5
Repair Systems & Information Group
Goodwill [Roll Forward]
December 30, 2017	613.2
Currency translation	3.2
Acquisitions and related adjustments	0.0
March 31, 2018	$ 616.4