Common Stock and Capital Surplus Disclosure [Line Items]

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- Definition

Amount of increase in the appropriate capital accounts and decrease in retained earnings by the fair value of the shares issued, which are accounted as stock dividends as of shareholders' record date by publicly-owned corporations in the United States.

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- Definition

Percentage of outstanding common stock issued as free share distribution prior to specified date.

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- Definition

Disclosure of percentage of proceeds per issuance of common stock, including conversions of bonds and notes to be credited to the common stock account.

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No definition available.

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- Definition

Treasury Stock Percentage of total issued shares

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- Definition

Amount authorized for purchase of share under share repurchase plan. Includes, but is not limited to, repurchase of stock and unit of ownership.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 505
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481520/505-30-50-4

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- Definition

Number of shares authorized to be purchased under share repurchase plan. Includes, but is not limited to, repurchase of stock and unit of ownership.

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- Definition

Number of shares that have been repurchased during the period and are being held in treasury.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-SubTopic 10
-Topic 505
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-2

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-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-Publisher FASB
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-Publisher FASB
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- Definition

Number of shares of common and preferred stock retired from treasury during the period.

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- Definition

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-SubTopic 10
-Topic 505
-Publisher FASB
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-URI https://asc.fasb.org/1943274/2147481549/505-30-45-1

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Common Stock and Capital Surplus (Narrative) (Detail) - JPY (¥)					2 Months Ended		5 Months Ended			12 Months Ended
	Nov. 29, 2024	Nov. 30, 2023	Feb. 28, 2023	Nov. 30, 2022	Jun. 30, 2024	Jan. 31, 2023	Mar. 31, 2025	Mar. 31, 2024	Oct. 31, 2022	Mar. 31, 2025	Nov. 14, 2024	May 15, 2024	Nov. 14, 2023	Nov. 14, 2022	May 16, 2022
Treasury Stock:
Treasury stock %							5.00%			5.00%
Minimum
Common Stock and Capital Surplus Disclosure [Line Items]
Percentage of proceeds per issuance of common stock, including conversions of bonds and notes, to be credited to the common stock account							50.00%			50.00%
Percentage of outstanding common stock issued as free share distribution prior to April 1, 1991							5.00%			5.00%
Maximum
Common Stock and Capital Surplus Disclosure [Line Items]
Percentage of outstanding common stock issued as free share distribution prior to April 1, 1991							10.00%			10.00%
Common stock \| Maximum
Treasury Stock:
Aggregated number of shares allowed for repurchase (in shares)											230,000,000	80,000,000	400,000,000	300,000,000	600,000,000
Aggregate amount of shares allowed for repurchase											¥ 300,000,000,000	¥ 100,000,000,000	¥ 400,000,000,000	¥ 150,000,000,000	¥ 300,000,000,000
Treasury stock common
Treasury Stock:
Number of own shares repurchased (in shares)					62,666,100	175,357,900	158,752,500	300,646,400	418,926,300
Treasury shares value					¥ 99,999,986,737	¥ 149,999,996,001	¥ 299,999,995,801	¥ 399,999,861,554	¥ 299,999,909,768
Treasury shares cancelled (in shares)	270,000,000	350,000,000	175,357,900	418,926,300
BK and TB \| Common stock
Common Stock and Capital Surplus Disclosure [Line Items]
Increase (decrease) by amount equal to the fair value of the shares issued by the application of U.S. accounting practices for issuance of free shares distribution made prior to April 1, 1991										¥ 1,910,106,000,000
BK and TB \| Unappropriated retained earnings:
Common Stock and Capital Surplus Disclosure [Line Items]
Increase (decrease) by amount equal to the fair value of the shares issued by the application of U.S. accounting practices for issuance of free shares distribution made prior to April 1, 1991										¥ (1,910,106,000,000)