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Related Parties and Related Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Jun. 27, 2025	Mar. 28, 2025	Jun. 27, 2025	Jun. 28, 2024	Jun. 30, 2023	Feb. 21, 2025
Related Party Transaction [Line Items]
Distributions from Flash Ventures			$ 176	$ 0	$ 0
Repayments of debt			100	0	0
Net transfers to Western Digital Corporation, including spin-off-related adjustments		$ (600)	(612)	275	376
Tax indemnification liability	$ 110		$ 110	0
Flash Ventures
Related Party Transaction [Line Items]
Ownership percentage	49.90%		49.90%
Equity investment	$ 85		$ 85
Flash Ventures \| Kioxia Corporation
Related Party Transaction [Line Items]
Ownership percentage	50.10%		50.10%
Related Party
Related Party Transaction [Line Items]
Accounts payable	$ 400		$ 400	313
Investment funding commitments, percentage	50.00%		50.00%
Manufacturing capacity percent operating	100.00%		100.00%
Costs incurred associated with reduction in utilization			$ 75	249
Repayments of debt			6
Net transfers to Western Digital Corporation, including spin-off-related adjustments			(585)	275	376
Tax indemnification liability	$ (2)		(2)			$ 112
Notes payable	550		550
Notes due to Western Digital Corporation	0		0	814
Notes due from Western Digital Corporation	0		0	102
Related Party \| WDC Subsidiaries
Related Party Transaction [Line Items]
Notes payable	553		553
Related Party \| Research And Development Commitments
Related Party Transaction [Line Items]
Related party transaction	130
Related Party \| Sale of NAND Components
Related Party Transaction [Line Items]
Notes due from Western Digital Corporation	65		65
Related Party \| Transition Services Agreement
Related Party Transaction [Line Items]
Related party expense			5
Related Party \| Transition Services Agreement, Additional Expense
Related Party Transaction [Line Items]
Related party expense			4
Related Party \| Flash Ventures
Related Party Transaction [Line Items]
Payments for equity method investments			3,400	3,400	$ 4,200
Accounts payable	$ 279		$ 279	$ 313
Related Party \| Flash Ventures \| Future Building Depreciation Payments
Related Party Transaction [Line Items]
Exchange rate	144.73		144.73
Other commitment	$ 264		$ 264
To be paid year one	32		32
To be paid year two	121		121
To be paid year three	97		97
To be paid year four	14		14
Related party transaction			209
Related Party \| K1, K2, And Y7 Facilities \| Future Building Depreciation Payments
Related Party Transaction [Line Items]
Other commitment	946		946
Related Party \| K1, K2, And Y7 Facilities \| Future Building Depreciation Payments \| Other current assets
Related Party Transaction [Line Items]
Other commitment	131		131
Related Party \| K1, K2, And Y7 Facilities \| Future Building Depreciation Payments \| Other noncurrent assets
Related Party Transaction [Line Items]
Other commitment	$ 815		$ 815
Related Party \| Maximum
Related Party Transaction [Line Items]
Investment funding commitments, percentage	50.00%		50.00%