Derivative Financial Instruments and Hedging (Notional Amounts of Derivative Instruments and Other, Fair Values of Derivative Instruments and Other before Offsetting) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions |
Sep. 30, 2026 |
Mar. 31, 2026 |
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| Derivatives, Fair Value [Line Items] | ||
| Derivative assets Fair value | ¥ 126,433 | ¥ 154,513 |
| Derivative liabilities Fair value | 93,669 | 118,058 |
| Futures | Variable Annuity and Variable Life Insurance Contracts | ||
| Derivatives, Fair Value [Line Items] | ||
| Notional amount | 940 | 1,741 |
| Derivative assets Fair value | 4 | 47 |
| Derivative liabilities Fair value | 13 | 6 |
| Foreign exchange contracts | Variable Annuity and Variable Life Insurance Contracts | ||
| Derivatives, Fair Value [Line Items] | ||
| Notional amount | 600 | 964 |
| Derivative assets Fair value | 4 | 8 |
| Derivative liabilities Fair value | ¥ 2 | ¥ 23 |
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- Definition Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Nominal or face amount used to calculate payment on derivative. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition 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. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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