Postretirement Plans - Summary of Change in Fair Value of Plan Assets (Detail) - U.S. Postretirement Health Care Plans - USD ($) $ in Millions	12 Months Ended
Dec. 28, 2019	Dec. 29, 2018
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	$ 12.1	$ 13.4
Actual (loss) gain on plan assets	1.5	(0.2)
Employer contributions	3.1	3.1
Plan participant contributions	0.3	0.3
Benefits paid	(4.2)	(4.5)
Fair value of plan assets at end of year	12.8	12.1
Unfunded status at end of year	$ (36.4)	$ (34.7)

Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses.

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- Definition

Amount of contributions received by defined benefit plan from participant which increase benefit obligation.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of contribution received by defined benefit plan from employer which increases plan assets.

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Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

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Amount of funded (unfunded) status of defined benefit plan, measured as difference between fair value of plan assets and benefit obligation. Includes, but is not limited to, overfunded (underfunded) status.

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Amount of payment to participant under defined benefit plan which decreases plan assets. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.

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