Postretirement Plans (Summary Of Target Allocation By Asset Category And Changes In Fair Value Of Plan Assets) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 29, 2012	Dec. 31, 2011	Jan. 01, 2011
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 964.0	$ 846.1	$ 793.0
Voluntary Employees Beneficiary Association Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	15.1	13.5
Voluntary Employees Beneficiary Association Plan Assets [Member] \| Cash And Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0.1	0.1
Voluntary Employees Beneficiary Association Plan Assets [Member] \| Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	8.5	7.4
Voluntary Employees Beneficiary Association Plan Assets [Member] \| Private Equity Partnerships Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	3.2	3.0
Voluntary Employees Beneficiary Association Plan Assets [Member] \| Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	2.1	2.1
Voluntary Employees Beneficiary Association Plan Assets [Member] \| Real Estate And Other Real Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1.2	0.9
Voluntary Employees Beneficiary Association Plan Assets [Member] \| Quoted Prices For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	11.9	10.5
Voluntary Employees Beneficiary Association Plan Assets [Member] \| Quoted Prices For Identical Assets (Level 1) [Member] \| Cash And Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0.1	0.1
Voluntary Employees Beneficiary Association Plan Assets [Member] \| Quoted Prices For Identical Assets (Level 1) [Member] \| Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	8.5	7.4
Voluntary Employees Beneficiary Association Plan Assets [Member] \| Quoted Prices For Identical Assets (Level 1) [Member] \| Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	2.1	2.1
Voluntary Employees Beneficiary Association Plan Assets [Member] \| Quoted Prices For Identical Assets (Level 1) [Member] \| Real Estate And Other Real Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1.2	0.9
Voluntary Employees Beneficiary Association Plan Assets [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	3.2	3.0
Voluntary Employees Beneficiary Association Plan Assets [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Private Equity Partnerships Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 3.2	$ 3.0

Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

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