Balance Sheet Components - Available-for-Sale Securities (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Oct. 02, 2015
Available-for-sale Securities:
Amortized Cost	$ 95.3	$ 93.2
Gross Unrealized Gains	0.0	0.1
Gross Unrealized Losses	0.0	(0.3)
Fair Value	95.3	93.0
CPTC loans
Available-for-sale Securities:
Amortized Cost	95.3	83.9
Gross Unrealized Gains	0.0	0.0
Gross Unrealized Losses	0.0	0.0
Fair Value	$ 95.3	83.9
Other
Available-for-sale Securities:
Amortized Cost		8.6
Gross Unrealized Gains		0.1
Gross Unrealized Losses		(0.3)
Fair Value		8.4
Non-U.S. government security
Available-for-sale Securities:
Amortized Cost		0.7
Gross Unrealized Gains		0.0
Gross Unrealized Losses		0.0
Fair Value		$ 0.7

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558

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-Section 50
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 45
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+ 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 210.5-02.2)
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