Equity and Other Equity Items - Disclosure of Classes of Share Capital (Detail) - Common stock issued [Member] - shares	12 Months Ended
Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2024
Disclosure of classes of share capital [line items]
Balance at beginning of year	15,794,987,460	16,314,987,460	16,314,987,460
Changes during the year	0	(520,000,000)	0
Balance at end of year	15,794,987,460	15,794,987,460	16,314,987,460

The increase (decrease) in the number of shares outstanding. [Refer: Number of shares outstanding]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
-Paragraph B10
-Subparagraph a
-Clause iv
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_B10_a_iv&doctype=Appendix&subtype=B
-URIDate 2025-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
-Paragraph 160
-Subparagraph a
-Clause iv
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_160_a_iv&doctype=Standard
-URIDate 2025-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2027-01-01
-Name IAS
-Number 1
-IssueDate 2025-01-01
-Paragraph 79
-Subparagraph a
-Clause iv
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_79_a_iv&doctype=Standard
-URIDate 2025-03-27

Name:	ifrs-full_IncreaseDecreaseInNumberOfSharesOutstanding
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration