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Investment in Securities (Information About Impairment and Upward or Downward Adjustments Resulting From Observable Price Changes) (Detail) - Equity security - JPY (¥)
¥ in Millions
12 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Schedule Of Gain Loss On Investments Held At Cost Balance Sheet and Income Statement Reported Amounts Summary [Line Items]    
Carrying value ¥ 67,820 ¥ 58,723
Accumulated impairments and downward adjustments (14,062) (13,880)
Accumulated upward adjustments 1,742 401
Impairments and downward adjustments (787) (208)
Upward adjustments ¥ 1,360 ¥ 163