Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-11

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-11

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-10

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Name:	us-gaap_CashAndCashEquivalentsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Fair Value of Financial Instruments - Schedule of Financial Instruments Carried at Fair Value (Details) - USD ($) $ in Millions	Mar. 29, 2026	Sep. 29, 2025	Jun. 29, 2025
Liabilities:
Forward equity contract		$ 371.1
Warrants		$ 33.6
Level 1 \| Money market funds
Assets:
Cash and cash equivalents, fair value disclosure	$ 36.8		$ 61.8
Level 1 \| U.S. treasury securities
Assets:
Cash and cash equivalents, fair value disclosure	201.3		224.6
Level 1 \| MACOM Shares
Assets:
Cash and cash equivalents, fair value disclosure	0.0		102.0
Level 2
Liabilities:
Forward equity contract	0.0		0.0
Level 2 \| Municipal bonds
Assets:
Cash and cash equivalents, fair value disclosure	104.8		79.2
Level 2 \| Corporate bonds
Assets:
Cash and cash equivalents, fair value disclosure	221.3		196.8
Level 2 \| Commercial paper
Assets:
Cash and cash equivalents, fair value disclosure	53.6		28.3
Level 2 \| Certificates of deposit
Assets:
Cash and cash equivalents, fair value disclosure	22.7		5.0
Level 3
Liabilities:
Warrants	0.0		0.0
Embedded derivative on New 2L Renesas Convertible Notes	$ 0.0		$ 0.0