Postretirement Plans - Summary of Weighted-Average Assumptions Used to Determine Accumulated Benefit Obligation (Detail)	Dec. 28, 2019	Dec. 29, 2018
U.S. Postretirement Health Care Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.10%	4.20%

Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(1)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

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Data Type:	num:percentItemType
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