Financial Risk Management - Summary of Loans and Advances at Amortized Cost (Parenthetical) (Detail) - JPY (¥) ¥ in Millions |
Mar. 31, 2026 |
Mar. 31, 2025 |
|---|---|---|
| Disclosure of credit risk exposure [line items] | ||
| Loans and advances at amortized cost | ¥ 130,516,241 | ¥ 125,190,819 |
| Gross carrying amount [member] | ||
| Disclosure of credit risk exposure [line items] | ||
| Loans and advances at amortized cost | 132,356,223 | 126,824,274 |
| Gross carrying amount [member] | Other [member] | Housing Loans [member] | Normal [member] | ||
| Disclosure of credit risk exposure [line items] | ||
| Loans and advances at amortized cost | 10,799,128 | 11,052,547 |
| Gross carrying amount [member] | Other [member] | Housing Loans [member] | Requiring caution [member] | ||
| Disclosure of credit risk exposure [line items] | ||
| Loans and advances at amortized cost | ¥ 12,719 | ¥ 14,461 |