Related Parties and Related Commitments and Contingencies - Net Transfer From (to) Parent (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 28, 2025	Jun. 27, 2025	Jun. 28, 2024	Jun. 30, 2023
Related Party Transaction [Line Items]
Net transfers to Western Digital Corporation, including spin-off-related adjustments	$ (600)	$ (612)	$ 275	$ 376
Notes due to (from) Western Digital Corporation		1,223
Notes due to (from) Western Digital Corporation			113	316
Other assets and liabilities, net, from Western Digital Corporation		105	0	0
Contribution of equity interest in Unis Venture from Western Digital Corporation		61	0	0
Property, plant and equipment from Western Digital Corporation		27	11	18
Tax balances from (to) Western Digital Corporation		8	(17)	(2)
Tax indemnification liability to Western Digital Corporation		112	0	0
Related Party
Related Party Transaction [Line Items]
Net transfers to Western Digital Corporation, including spin-off-related adjustments		(585)	275	376
Notes due to (from) Western Digital Corporation		(1,223)
Notes due to (from) Western Digital Corporation			(113)	(316)
Other assets and liabilities, net, from Western Digital Corporation		(105)	0	0
Contribution of equity interest in Unis Venture from Western Digital Corporation		(61)	0	0
Property, plant and equipment from Western Digital Corporation		(27)	(11)	(18)
Tax balances from (to) Western Digital Corporation		(8)	17	2
Accumulated other comprehensive loss transferred to Western Digital Corporation		10	0	0
Tax indemnification liability to Western Digital Corporation		112	0	0
Net transfers (to) from Western Digital Corporation per Consolidated Statements of Cash Flows		$ (1,887)	$ 394	$ 676