Allocation by Investment Type (Detail)	12 Months Ended
Sep. 30, 2016	Oct. 02, 2015
Retirement Benefits
Actual, Allocation Percentage	100.00%	100.00%
Equity Securities
Retirement Benefits
Target, Allocation Percentage, Range minimum	35.00%
Target, Allocation Percentage, Range maximum	70.00%
Actual, Allocation Percentage	56.40%	56.80%
Debt Securities
Retirement Benefits
Target, Allocation Percentage, Range minimum	30.00%
Target, Allocation Percentage, Range maximum	65.00%
Actual, Allocation Percentage	37.10%	38.20%
Cash
Retirement Benefits
Target, Allocation Percentage	0.00%
Actual, Allocation Percentage	6.50%	5.00%

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

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)(i)
-URI http://asc.fasb.org/extlink&oid=65897934&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)(i)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

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

+ References

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Target allocation minimum 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=65897934&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=65897934&loc=d3e2446-114920

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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=65897934&loc=d3e2446-114920

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(1)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

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