Retirement Plans (Schedule of Actual and Target Allocations of Plan Assets) (Details) (Pensions [Member])	12 Months Ended
Dec. 27, 2014	Dec. 28, 2013
Equity [Member]
Target Allocations [Abstract]
Target plan asset allocations range, minimum (percent)	60.00%
Target plan asset allocations range, maximum (percent)	75.00%
Fixed income [Member]
Target Allocations [Abstract]
Target plan asset allocations range, minimum (percent)	25.00%
Target plan asset allocations range, maximum (percent)	35.00%
Alternative and other investments [Member]
Target Allocations [Abstract]
Target plan asset allocations range, minimum (percent)	10.00%
Target plan asset allocations range, maximum (percent)	30.00%
Minimum [Member] \| Equity [Member]
Target Allocations [Abstract]
Actual plan asset allocations (percent)	48.00%	53.00%
Minimum [Member] \| Fixed income [Member]
Target Allocations [Abstract]
Actual plan asset allocations (percent)	26.00%	23.00%
Minimum [Member] \| Alternative and other investments [Member]
Target Allocations [Abstract]
Actual plan asset allocations (percent)	5.00%	2.00%
Maximum [Member] \| Equity [Member]
Target Allocations [Abstract]
Actual plan asset allocations (percent)	62.00%	65.00%
Maximum [Member] \| Fixed income [Member]
Target Allocations [Abstract]
Actual plan asset allocations (percent)	33.00%	33.00%
Maximum [Member] \| Alternative and other investments [Member]
Target Allocations [Abstract]
Actual plan asset allocations (percent)	26.00%	24.00%

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

+ References

+ Details

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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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