Investments - Investment Securities, Aggregated by Investment Type and Length of Time (Details) $ in Millions	Mar. 31, 2024 USD ($) security	Jun. 25, 2023 USD ($) security
Fair Value
Less than 12 Months	$ 580.3	$ 520.9
Greater than 12 Months	322.1	463.1
Total	902.4	984.0
Unrealized Loss
Less than 12 Months	(0.5)	(1.6)
Greater than 12 Months	(10.4)	(21.1)
Total	$ (10.9)	$ (22.7)
Number of securities with an unrealized loss
Less than 12 Months | security	146	95
Greater than 12 Months | security	77	234
Total | security	223	329
Corporate bonds
Fair Value
Less than 12 Months	$ 82.7	$ 151.5
Greater than 12 Months	219.5	324.1
Total	302.2	475.6
Unrealized Loss
Less than 12 Months	(0.2)	(0.5)
Greater than 12 Months	(7.8)	(16.2)
Total	(8.0)	(16.7)
U.S. treasury securities
Fair Value
Less than 12 Months	464.0	229.3
Greater than 12 Months	15.7	31.1
Total	479.7	260.4
Unrealized Loss
Less than 12 Months	(0.3)	(0.5)
Greater than 12 Months	(0.2)	(0.9)
Total	(0.5)	(1.4)
Municipal bonds
Fair Value
Less than 12 Months	13.9	61.4
Greater than 12 Months	76.9	105.9
Total	90.8	167.3
Unrealized Loss
Less than 12 Months	0.0	(0.4)
Greater than 12 Months	(2.4)	(4.0)
Total	(2.4)	(4.4)
U.S. agency securities
Fair Value
Less than 12 Months	19.7	74.8
Greater than 12 Months	10.0	2.0
Total	29.7	76.8
Unrealized Loss
Less than 12 Months	0.0	(0.2)
Greater than 12 Months	0.0	0.0
Total	$ 0.0	(0.2)
Commercial paper
Fair Value
Less than 12 Months		3.9
Greater than 12 Months		0.0
Total		3.9
Unrealized Loss
Less than 12 Months		0.0
Greater than 12 Months		0.0
Total		$ 0.0