Shareholders' Equity (Narrative) (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	9 Months Ended
Sep. 29, 2017	Aug. 31, 2015
2015 Stock Repurchase Program [Member]
Equity, Class of Stock [Line Items]
Stock repurchase program approved amount		$ 400.0
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 19.0
Retained Earnings [Member]
Equity, Class of Stock [Line Items]
Stock Repurchased During Period, Value	$ 94.1
Open Market Purchases [Member] \| 2015 Stock Repurchase Program [Member]
Equity, Class of Stock [Line Items]
Stock Repurchased During Period, Shares	3.1
Accelerated Share Repurchases, Final Price Paid Per Share	$ 36.07
Stock Repurchased During Period, Value	$ 111.5

Final price paid per share for the purchase of the targeted number of shares, determined by an average market price over a fixed period of time.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 25
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6405686&loc=d3e22802-112653

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Amount of stock repurchase plan authorized.

+ References

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Amount remaining of a stock repurchase plan authorized.

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Number of shares that have been repurchased and retired during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21463-112644

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-Name Accounting Standards Codification
-Topic 210
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Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21463-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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