Shareholders' Equity - Unrecognized Share-based Compensation (Details) $ in Millions	3 Months Ended
Oct. 04, 2019 USD ($)
Employee Service Share-based Compensation, Unrecognized Service Costs [Line Items]
Unamortized Compensation Costs	$ 783
Options
Employee Service Share-based Compensation, Unrecognized Service Costs [Line Items]
Unamortized Compensation Costs	$ 5
Weighted Average Service Period	9 months 18 days
RSUs and PSUs
Employee Service Share-based Compensation, Unrecognized Service Costs [Line Items]
Unamortized Compensation Costs	$ 722
Weighted Average Service Period	2 years 10 months 24 days
ESPP
Employee Service Share-based Compensation, Unrecognized Service Costs [Line Items]
Unamortized Compensation Costs	$ 56
Weighted Average Service Period	1 year 8 months 12 days

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

[Line Items] for Schedule of employee share-based awards, unrecognized compensation in tabular format.

+ References

No definition available.

+ Details

Name:	wdc_EmployeeServiceSharebasedCompensationUnrecognizedServiceCostsLineItems
Namespace Prefix:	wdc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=wdc_EmployeeStockPurchasePlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: