Organization and Basis of Presentation (Policies)	3 Months Ended
Organization and Basis of Presentation (Policies)	Oct. 01, 2021
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 that address the evolving needs of the information technology (“IT”) industry and the infrastructure that enables the proliferation of data in virtually every other industry. The Company creates environments for data to thrive. The Company is driving the innovation needed to help customers capture, preserve, access and transform an ever-increasing diversity of data. Everywhere data lives, from advanced data centers to mobile sensors to personal devices, the Company’s industry-leading solutions deliver the possibilities 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 fiscal year ended July 2, 2021. 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 fiscal year ended July 2, 2021. The results of operations for interim periods are not necessarily indicative of results to be expected for the full year.
Fiscal Year	Fiscal YearThe 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 2022, which ends on July 1, 2022, and 2021, which ended on July 2, 2021, are each comprised of 52 weeks, with all quarters presented consisting of 13 weeks.
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 the ongoing COVID-19 pandemic. However, actual results could differ materially from these estimates and be significantly affected by the severity and duration of the pandemic, the extent of actions to contain or treat COVID-19, the timing, distribution, efficacy and public acceptance of vaccines around the world, any possible resurgence of COVID-19, including the emergence of more contagious or vaccine-resistant variants and how quickly and to what extent normal economic and operating activity can resume.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Accounting Pronouncements Recently Adopted In December 2019, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2019-12, “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes” (“ASU 2019-12”). ASU 2019-12 removes certain exceptions for recognizing deferred taxes for investments, performing intraperiod allocation and calculating income taxes in interim periods. The ASU also adds guidance to reduce complexity in certain areas, including recognizing deferred taxes for tax goodwill and allocating taxes to members of a consolidated group. The Company adopted this ASU on July 3, 2021, which is the beginning of fiscal 2022, and its adoption did not have a material impact on the Company’s Condensed Consolidated Financial Statements. Recently Issued Accounting Pronouncements Not Yet Adopted In August 2020, the FASB issued 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 current 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. For instruments that do not have a component mandatorily settled in cash, the change will likely result in a higher amount of share dilution in the calculation of earnings per share. The Company expects to adopt this ASU in the first quarter of fiscal 2023, and is currently assessing the impact of adoption.
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.