Postretirement Plans - Summary of Components of Net Periodic Benefit Costs and Other Amounts Recognized in Other Comprehensive Income (Loss) (Detail) - U.S. Postretirement Health Care Plans - USD ($) $ in Millions	12 Months Ended
Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Net periodic benefit cost:
Interest cost	$ 1.9	$ 1.8	$ 2.1
Expected return on plan assets	(0.7)	(0.8)	(0.8)
Amortization of unrecognized gain	(0.8)	(0.4)	(0.3)
Net periodic benefit cost	0.4	0.6	1.0
Changes in benefit obligations recognized in OCI, net of tax:
Net (gain) loss	$ 2.4	$ (1.4)	$ 0.6

Postretirement Plans - Summary of Components of Net Periodic Benefit Costs and Other Amounts Recognized in Other Comprehensive Income (Loss) (Detail) - U.S. Postretirement Health Care Plans - USD ($)
$ in Millions

12 Months Ended

Dec. 28, 2019

Dec. 29, 2018

Dec. 30, 2017

Net periodic benefit cost:

Interest cost

$ 1.9

$ 1.8

$ 2.1

Expected return on plan assets

(0.7)

(0.8)