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Joint Operations - Details of Significant Joint Operations (Detail)	12 Months Ended
	Dec. 31, 2025
Disclosure of joint operations [line items]
Category of business	Steel manufacturing and sales	[1]
Myanmar A-1/A-3 mine [member]
Disclosure of joint operations [line items]
Category of business	Mine development and gas production
Ownership (%)	51.00%
Location	Myanmar
Offshore Midstream [member]
Disclosure of joint operations [line items]
Category of business	Gas transportation facility
Ownership (%)	51.00%
Location	Myanmar
Mt. Thorley J/V [member]
Disclosure of joint operations [line items]
Category of business	Mine development
Ownership (%)	20.00%
Location	Australia
POSMAC J/V [member]
Disclosure of joint operations [line items]
Category of business	Mine development
Ownership (%)	20.00%
Location	Australia
[1] As of December 31, 2025, the entities are classified as consolidated subsidiaries since the Company has control over the investees although the Company’s percentage of ownership is 50% or less, considering the structure of the entities’ Board of Directors and others.

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- Definition

The description of the nature of the entity's operations and principal activities.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
-Paragraph 141
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2027-01-01
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- Definition

The principal place of business of a joint operation. [Refer: Total for all joint operations [member]; Principal place of business]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2025-01-01
-Paragraph 21
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-Number 12
-IssueDate 2025-01-01
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