Postretirement Plans - Summary of Target Allocation and Weighted-Average Asset Allocation by Asset Category and Fair Value of Plan Assets (Detail) (USD $) In Millions, unless otherwise specified				12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended
Dec. 28, 2013	Dec. 29, 2012	Dec. 31, 2011	Dec. 28, 2013 Voluntary Employees Beneficiary Association Plan Assets [Member]	Dec. 29, 2012 Voluntary Employees Beneficiary Association Plan Assets [Member]	Dec. 28, 2013 Voluntary Employees Beneficiary Association Plan Assets [Member] Equity securities [Member]	Dec. 29, 2012 Voluntary Employees Beneficiary Association Plan Assets [Member] Equity securities [Member]	Dec. 28, 2013 Voluntary Employees Beneficiary Association Plan Assets [Member] Hedge funds [Member]	Dec. 29, 2012 Voluntary Employees Beneficiary Association Plan Assets [Member] Hedge funds [Member]	Dec. 28, 2013 Voluntary Employees Beneficiary Association Plan Assets [Member] Debt securities and cash [Member]	Dec. 29, 2012 Voluntary Employees Beneficiary Association Plan Assets [Member] Debt securities and cash [Member]	Dec. 28, 2013 Voluntary Employees Beneficiary Association Plan Assets [Member] Real estate and other real assets [Member]	Dec. 29, 2012 Voluntary Employees Beneficiary Association Plan Assets [Member] Real estate and other real assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation				100.00%		56.00%		24.00%		14.00%		6.00%
Actual weighted-average asset allocation				100.00%	100.00%	57.00%	56.00%	24.00%	21.00%	13.00%	15.00%	6.00%	8.00%
Fair value of plan assets	$ 1,015.4	$ 964.0	$ 846.1	$ 15.0	$ 15.1	$ 8.6	$ 8.5	$ 3.6	$ 3.2

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 30

-Section 35

-Paragraph 50

-URI http://asc.fasb.org/extlink&oid=29635418&loc=d3e12355-114930

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- Definition

Target allocation of investments of this type to total plan assets presented on a weighted average basis.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (d)(i)

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 5

-Subparagraph (c)(i)

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e2446-114920

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- Definition

Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 5

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e2446-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (d)(1)

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920

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