Employee benefits - Summary of Fair Value of Plan Assets Japanese Plans (Parenthetical) (Detail) - Japanese Defined Benefit Plans [Member]	Mar. 31, 2024	Mar. 31, 2023
Defined Benefit Plan Japanese National and local Governments Debt Securities [Member]
Disclosure of fair value of plan assets [line items]
Defined Benefit Plan Percentage of Amount Contributed To Fair Value Of Plan Assets	84.00%	85.00%
Defined Benefit Plan Foreign National and Local Governments Debt Securities [Member]
Disclosure of fair value of plan assets [line items]
Defined Benefit Plan Percentage of Amount Contributed To Fair Value Of Plan Assets	16.00%	15.00%

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

No definition available.

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