Credit Quality of Financial Assets and the Allowance for Credit Losses - Summary of Allowance for Credit Losses for Installment Loans (Parenthetical) (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
Sep. 30, 2024	Sep. 30, 2023
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for credit losses	¥ 7,319	¥ 8,616
Total charge-offs	6,620	14,706
Purchased loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Total charge-offs	608	7,612
Purchased loans \| Financial asset acquired with credit deterioration
Financing Receivable, Allowance for Credit Losses [Line Items]
Total charge-offs	¥ 597	¥ 7,580

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

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Amount of writeoff of financing receivable, charged against allowance for credit loss.

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Amount of expense (reversal of expense) for expected credit loss on accounts receivable.

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