Post employment benefits - Balance sheet analysis of post employment plans (Parenthetical) (Details) - USD ($) $ in Millions	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2023
DPS
Disclosure of defined benefit plans [line items]
Surplus/deficit in plan	$ 608	$ 689	$ 742
GIGIPS
Disclosure of defined benefit plans [line items]
Surplus/deficit in plan	417	332	328
Other Schemes
Disclosure of defined benefit plans [line items]
Surplus/deficit in plan	$ 136	$ 125	$ 140

The fair value of any plan assets, less the present value of the defined benefit obligation. [Refer: Plan assets [member]]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2024-01-01
-Paragraph 57
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2024-en-r&anchor=para_57_a&doctype=Standard
-URIDate 2024-03-27

Name:	ifrs-full_SurplusDeficitInPlan
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant