Investments - Marketable Investments by Type (Details) - USD ($) $ in Millions	Jun. 26, 2022	Jun. 27, 2021
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 772.2	$ 770.5
Gross Unrealized Gains	0.1	5.5
Gross Unrealized Losses	(23.0)	(0.4)
Estimated Fair Value	749.3	775.6
Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	166.5	139.4
Gross Unrealized Gains	0.1	1.9
Gross Unrealized Losses	(4.4)	0.0
Estimated Fair Value	162.2	141.3
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	465.8	456.5
Gross Unrealized Gains	0.0	3.3
Gross Unrealized Losses	(17.8)	(0.3)
Estimated Fair Value	448.0	459.5
U.S. agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	4.0	15.8
Gross Unrealized Gains	0.0	0.0
Gross Unrealized Losses	(0.1)	0.0
Estimated Fair Value	3.9	15.8
U.S. treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	66.5	72.3
Gross Unrealized Gains	0.0	0.3
Gross Unrealized Losses	(0.7)	(0.1)
Estimated Fair Value	65.8	72.5
Certificates of deposit
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		16.5
Gross Unrealized Gains		0.0
Gross Unrealized Losses		0.0
Estimated Fair Value	0.0	16.5
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		50.0
Gross Unrealized Gains		0.0
Gross Unrealized Losses		0.0
Estimated Fair Value		50.0
Variable rate demand notes
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	69.4	20.0
Gross Unrealized Gains	0.0	0.0
Gross Unrealized Losses	0.0	0.0
Estimated Fair Value	$ 69.4	$ 20.0

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost excluding accrued interest, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

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Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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