Employee benefits - Summary of Weighted-Average Actuarial Assumptions Used to Determine the Present Value of Defined Benefit Obligations (Detail)	Mar. 31, 2022	Mar. 31, 2021	Apr. 01, 2020
Japanese Defined Benefit Plans [Member]
Disclosure of significant weighted average actuarial assumptions used to determine the present value of defined benefit obligations explanatory [Line Items]
Actuarial assumption of discount rates	0.70%	0.60%	0.60%
Foreign Defined Benefit Plan [Member]
Disclosure of significant weighted average actuarial assumptions used to determine the present value of defined benefit obligations explanatory [Line Items]
Actuarial assumption of discount rates	2.50%	1.40%	2.10%

The discount rate used as the significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit obligation, at present value; Actuarial assumptions [member]]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2021-01-01
-Paragraph 144
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2021-en-r&anchor=para_144&doctype=Standard
-URIDate 2021-03-24

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Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant