Organization and Basis of Presentation (Policies)	3 Months Ended
Organization and Basis of Presentation (Policies)	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Western Digital Corporation (“Western Digital” or the “Company”) is a leading developer, manufacturer, and provider of data storage devices and solutions based on both flash-based products (“Flash”) and hard disk drives (“HDD”) technologies. With dedicated Flash and HDD business units driving advancements in memory technologies, the Company creates and drives innovations needed to help customers capture, preserve, access, and transform an ever-increasing diversity of data. The accounting policies followed by the Company are set forth in Part II, Item 8, Note 1, Organization and Basis of Presentation, of the Notes to Consolidated Financial Statements included in the Company’s Annual Report on Form 10‑K for the year ended July 1, 2022. In the opinion of management, all adjustments necessary to fairly state the Condensed Consolidated Financial Statements have been made. All such adjustments are of a normal, recurring nature. Certain information and footnote disclosures normally included in the Consolidated Financial Statements prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). These Condensed Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and the notes thereto included in the Company’s Annual Report on Form 10‑K for the year ended July 1, 2022. The results of operations for interim periods are not necessarily indicative of results to be expected for the full year.
Fiscal Year	Fiscal Year The Company’s fiscal year ends on the Friday nearest to June 30 and typically consists of 52 weeks. Approximately every five to six years, the Company reports a 53-week fiscal year to align the fiscal year with the foregoing policy. Fiscal years 2023, which ends on June 30, 2023, and 2022, which ended on July 1, 2022, are each comprised of 52 weeks, with all quarters presented consisting of 13 weeks.
Segment Reporting	Segment Reporting The Company manufactures, markets, and sells data storage devices and solutions in the U.S. and in foreign countries through its sales personnel, dealers, distributors, retailers, and subsidiaries. The Company manages and reports under two reportable segments: Flash and HDD. The Company’s Chief Operating Decision Maker (“CODM”) evaluates performance of the Company and makes decisions regarding allocation of resources based on each operating segment’s net revenue and gross margin. Because of the integrated nature of the Company’s production and distribution activities, separate segment asset measures are not available or reviewed by the CODM to evaluate the performance of or to allocate resources to the segments.
Use of Estimates	Use of Estimates Company management has made estimates and assumptions relating to the reporting of certain assets and liabilities in conformity with U.S. GAAP. These estimates and assumptions have been applied using methodologies that are consistent throughout the periods presented with consideration given to the potential impacts of current macroeconomic conditions. However, actual results could differ materially from these estimates.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Accounting Pronouncements Recently Adopted In August 2020, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2020-06, “Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity” (“ASU 2020-06”). ASU 2020-06 reduces the number of accounting models for convertible debt instruments and convertible preferred stock and results in fewer instruments with embedded conversion features being separately recognized from the host contract as compared with prior standards. Those instruments that do not have a separately recognized embedded conversion feature will no longer recognize a debt issuance discount related to such a conversion feature and would recognize less interest expense on a periodic basis. Additionally, the ASU amends the calculation of the share dilution impact related to a conversion feature and eliminates the treasury method as an option. The Company adopted the new standard effective July 2, 2022, the first day of the year ending June 30, 2023, using the modified retrospective method. On the date of adoption, the Company recorded a reduction in Additional Paid-In Capital of $128 million, a reduction of unamortized debt discount of $48 million, a reduction of deferred income tax liabilities of $11 million, and an increase to retained earnings of $91 million for the after-tax impact of previously recognized amortization of the debt discount associated with the Company’s convertible senior notes. In November 2021, the FASB issued ASU No. 2021-10, “Government Assistance (Topic 832): Disclosures by Business Entities about Government Assistance” (“ASU 2021-10”). ASU 2021-10 increases the transparency of government assistance received by requiring most business entities to disclose information about government assistance received, including (1) the types of assistance, (2) the entity’s accounting for the assistance, and (3) the effect of the assistance on an entity’s financial statements. This ASU is effective for fiscal years (and interim periods within those fiscal years) beginning after December 15, 2021, which for the Company is the first quarter of 2023. The Company adopted this ASU on July 2, 2022, the first day of the year ending June 30, 2023, and the adoption did not have a material impact on its Condensed Consolidated Financial Statements.
Fair Value Measurements and Investments	Financial assets and liabilities that are remeasured and reported at fair value at each reporting period are classified and disclosed in one of the following three levels: Level 1. Quoted prices in active markets for identical assets or liabilities. Level 2. Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3. Inputs that are unobservable for the asset or liability and that are significant to the fair value of the assets or liabilities.