Net Income per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Oct. 03, 2025	Sep. 27, 2024	Jun. 27, 2025	Feb. 21, 2025
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Shares issued (in shares)	147.0		146.0	145.0
Par value (in dollars per share)	$ 0.01		$ 0.01	$ 0.01
Net Income (Loss)	$ 112	$ 211
Weighted average shares outstanding:
Basic (in shares)	146.0	145.0
Diluted (in shares)	149.0	145.0
Net income per common share:
Basic (in dollars per share)	$ 0.77	$ 1.46
Diluted (in dollars per share)	$ 0.75	$ 1.46
Antidilutive weighted-average shares (in shares)	0.7
Western Digital Corporation
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Percent distribution of shares				80.10%