| Cover Page | Oct. 28, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Oct. 28, 2020 |
| Entity Registrant Name | WESTERN DIGITAL CORPORATION |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-08703 |
| Entity Tax Identification Number | 33-0956711 |
| Entity Address, Address Line One | 5601 Great Oaks Parkway |
| Entity Address, City or Town | San Jose |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 95119 |
| City Area Code | 408 |
| Local Phone Number | 717-6000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $.01 Par Value Per Share |
| Trading Symbol | WDC |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000106040 |
| Amendment Flag | false |
