Auditor's Remuneration - Summary of Auditors' Remuneration (Detail) - USD ($) $ in Thousands	12 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Auditors remuneration [line items]
Other assurance services	$ 594	$ 1,343	$ 1,849
Total assurance services	13,991	23,193	15,867
Other services	537	657	631
Total fees	14,528	23,850	16,498
Parent [member]
Auditors remuneration [line items]
Audit	4,033	3,909	3,381
Subsidiaries, joint ventures and associates [member]
Auditors remuneration [line items]
Audit	5,275	13,902	7,040
Audit-related assurance services [member]
Auditors remuneration [line items]
Audit	4,089	4,039	3,597
Corporate finance [member]
Auditors remuneration [line items]
Other services	55	104	42
Other services [member]
Auditors remuneration [line items]
Other services	$ 482	$ 553	$ 589

Auditors remuneration assurance services.

No definition available.

Name:	bhp_AuditorsRemunerationAssuranceServices
Namespace Prefix:	bhp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Other assurance services comprise the aggregate fees for assurance and related services that are related to the performance of the audit or review of the financial statements and are not reported under total audit fees.

+ References

No definition available.

+ Details

Name:	bhp_AuditorsRemunerationForOtherAssuranceServices
Namespace Prefix:	bhp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Auditors remuneration.

+ References

No definition available.

+ Details

Name:	bhp_AuditorsRemunerationLineItems
Namespace Prefix:	bhp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of fees paid or payable to the entity's auditors.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 112
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_112_c&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_AuditorsRemuneration
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of fees paid or payable to the entity's auditors for auditing services.

+ References

+ Details

Name:	ifrs-full_AuditorsRemunerationForAuditServices
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of fees paid or payable to the entity's auditors for services that the entity does not separately disclose in the same statement or note.

+ References

+ Details

Name:	ifrs-full_AuditorsRemunerationForOtherServices
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	bhp_AuditorsAxis=ifrs-full_ParentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	bhp_AuditorsAxis=bhp_SubsidiariesJointVenturesAndAssociatesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	bhp_AuditorsAxis=bhp_AuditrelatedAssuranceServicesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	bhp_AuditorsAxis=bhp_CorporateFinanceServicesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	bhp_AuditorsAxis=bhp_OtherServicesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: