Postretirement Plans - Summary of Amounts Included in Accumulated Other Comprehensive Income on Accompanying Consolidated Balance Sheets (Detail) - U.S. Postretirement Health Care Plans - USD ($) $ in Millions	Dec. 28, 2019	Dec. 29, 2018
Defined Benefit Plan Disclosure [Line Items]
Net gain, net of tax of $1.1 million and $3.1 million, respectively	$ 3.2	$ 5.6
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent
Defined Benefit Plan Disclosure [Line Items]
AOCI, tax	$ 1.1	$ 3.1

Postretirement Plans - Summary of Amounts Included in Accumulated Other Comprehensive Income on Accompanying Consolidated Balance Sheets (Detail) - U.S. Postretirement Health Care Plans - USD ($)
$ in Millions

Dec. 28, 2019

Dec. 29, 2018

Defined Benefit Plan Disclosure [Line Items]

Net gain, net of tax of $1.1 million and $3.1 million, respectively

$ 3.2

$ 5.6

Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent

Defined Benefit Plan Disclosure [Line Items]

AOCI, tax

$ 1.1

$ 3.1