Segments - Assets by Segment (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 30, 2017
Segment Reporting Information [Line Items]
Assets	$ 5,317.6	$ 5,249.1
Operating Segments
Segment Reporting Information [Line Items]
Assets	5,178.4	5,114.3
Operating Segments | Commercial & Industrial Group
Segment Reporting Information [Line Items]
Assets	1,136.2	1,113.9
Operating Segments | Snap-on Tools Group
Segment Reporting Information [Line Items]
Assets	762.0	714.3
Operating Segments | Repair Systems & Information Group
Segment Reporting Information [Line Items]
Assets	1,311.5	1,314.3
Operating Segments | Financial Services
Segment Reporting Information [Line Items]
Assets	1,968.7	1,971.8
Corporate
Segment Reporting Information [Line Items]
Assets	204.5	200.6
Elimination of intersegment receivables
Segment Reporting Information [Line Items]
Assets	$ (65.3)	$ (65.8)