Related Parties and Related Commitments and Contingencies - Net Transfer From (to) Parent (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Mar. 28, 2025	Dec. 27, 2024	Sep. 27, 2024	Mar. 29, 2024	Dec. 29, 2023	Sep. 29, 2023	Mar. 28, 2025	Mar. 29, 2024
Related Party Transaction [Line Items]
Net transfers to Western Digital Corporation, including spin-off-related adjustments	$ (1,076)	$ (92)	$ 583	$ 63	$ 152	$ 19	$ (10)
Notes due to (from) Western Digital Corporation							1,223
Notes due to (from) Western Digital Corporation								$ 113
Other assets and liabilities, net, from Western Digital Corporation							105	0
Contribution of equity interest in Unis Venture from Western Digital Corporation							61	0
Property, plant and equipment from Western Digital Corporation							27	5
Tax balances to Western Digital Corporation							8	2
Tax indemnification liability to Western Digital Corporation							112	0
Related Party
Related Party Transaction [Line Items]
Net transfers to Western Digital Corporation, including spin-off-related adjustments							(585)	234
Notes due to (from) Western Digital Corporation							(1,223)
Notes due to (from) Western Digital Corporation								(113)
Other assets and liabilities, net, from Western Digital Corporation							(105)	0
Contribution of equity interest in Unis Venture from Western Digital Corporation							(61)	0
Property, plant and equipment from Western Digital Corporation							(27)	(5)
Tax balances to Western Digital Corporation							(8)	(2)
Accumulated other comprehensive loss transferred to Western Digital Corporation							10	0
Tax indemnification liability to Western Digital Corporation							112	0
Net transfers (to) from Western Digital Corporation per Condensed Consolidated Statements of Cash Flows							$ (1,887)	$ 340