Mizuho Financial (MFG) 20-F 26 Jun 24 2024 FY Annual report (foreign) Financial data

Cover Page

Cover Page	12 Months Ended
	Mar. 31, 2024 shares
Document Information [Line Items]
Document Type	20-F
Amendment Flag	false
Document Period End Date	Mar. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	FY
Entity Registrant Name	Mizuho Financial Group, Inc.
Entity Central Index Key	0001335730
Current Fiscal Year End Date	--03-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Document Annual Report	true
Document Transition Report	false
Document Shell Company Report	false
Entity Shell Company	false
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding	2,539,249,894
Document Accounting Standard	U.S. GAAP
Entity File Number	001-33098
Entity Incorporation, State or Country Code	M0
Document Registration Statement	false
Entity Address, Address Line One	1-5-5 Otemachi
Entity Address, City or Town	Chiyoda-ku
Entity Address, Postal Zip Code	100-8176
Entity Address, Country	JP
ICFR Auditor Attestation Flag	true
Auditor Name	Ernst & Young ShinNihon LLC
Auditor Firm ID	789
Auditor Location	Tokyo, Japan
Document Financial Statement Error Correction [Flag]	false
American depositary shares
Document Information [Line Items]
Security Exchange Name	NYSE
Title of 12(b) Security	American depositary shares, each of whichrepresents two shares of common stock
Trading Symbol	MFG
Common Stock
Document Information [Line Items]
Title of 12(b) Security	Common Stock, without par value
No Trading Symbol Flag	true
Business Contact [Member]
Document Information [Line Items]
Contact Personnel Name	Yasutoshi Tanaka
Entity Address, Address Line One	1-5-5 Otemachi
Entity Address, City or Town	Chiyoda-ku
Entity Address, Postal Zip Code	100-8176
Entity Address, Country	JP
City Area Code	81-3
Local Phone Number	5224-1111

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023
Assets:
Cash and due from banks	¥ 2,046,324	¥ 2,241,929
Interest-bearing deposits in other banks	72,066,719	65,750,366
Call loans and funds sold	1,392,098	1,647,472
Receivables under resale agreements	20,534,728	11,695,014
Receivables under securities borrowing transactions	2,351,784	1,891,576
Trading account assets (including assets pledged that secured parties are permitted to sell or repledge of ¥7,355,733 million in 2023 and ¥11,722,063 million in 2024)	36,759,812	29,641,038
Investments (Note 3):
Available-for-sale securities (including assets pledged that secured parties are permitted to sell or repledge of ¥2,466,444 million in 2023 and ¥2,692,031 million in 2024), net of allowance	17,713,335	23,233,769
Held-to-maturity securities (including assets pledged that secured parties are permitted to sell or repledge of ¥1,594,501 million in 2023 and ¥3,767,997 million in 2024)	4,047,547	2,050,107
Equity securities	5,152,893	3,691,870
Other investments	884,496	667,201
Loans (Notes 4 and 5)	98,444,745	94,175,757
Allowance for credit losses on loans	(750,071)	(700,959)
Loans, net of allowance	97,694,674	93,474,798
Premises and equipment—net (Note 6)	1,714,485	1,653,888
Due from customers on acceptances	437,529	405,742
Accrued income	691,529	510,791
Goodwill (Note 7)	164,458	92,928
Intangible assets (Note 7)	44,984	44,681
Deferred tax assets	195,606	386,592
Other assets (Note 12)	8,280,151	9,700,960
Total assets	272,173,152	248,780,722
Liabilities and equity:
Noninterest-bearing deposits	33,554,817	33,136,655
Interest-bearing deposits	95,039,351	92,625,324
Noninterest-bearing deposits	3,359,545	3,042,821
Interest-bearing deposits	40,408,034	36,130,825
Due to trust accounts	245,611	749,382
Call money and funds purchased	1,660,682	1,814,874
Payables under repurchase agreements (Note 28)	38,104,868	25,737,154
Payables under securities lending transactions (Note 28)	1,350,435	886,391
Other short-term borrowings (including liabilities accounted for at fair value of ¥153,044 million in 2024) (Notes 11 and 26)	3,644,912	3,397,329
Trading account liabilities	20,621,160	19,362,943
Bank acceptances outstanding	437,529	405,742
Income taxes payable	87,994	88,277
Deferred tax liabilities	31,685	25,424
Accrued expenses	649,010	442,729
Long-term debt (including liabilities accounted for at fair value of ¥2,680,164 million in 2023, and ¥2,876,287 million in 2024) (Notes 11 and 26)	16,277,331	14,893,023
Other liabilities (Note 12)	6,268,999	6,316,695
Total liabilities	261,741,965	239,055,588
Commitments and contingencies (Note 22)
MHFG shareholders' equity:
Common stock (Note 14)—no par value, authorized 4,800,000,000 shares, and issued 2,539,249,894 shares at March 31, 2023 and 2024	5,833,660	5,832,729
Retained earnings	3,120,236	2,442,153
Accumulated other comprehensive income (loss), net of tax (Note 16)	984,578	649,395
Less: Treasury stock, at cost—Common stock 5,027,306 shares at March 31, 2023, and 4,739,805 shares at March 31, 2024	(9,403)	(8,786)
Total MHFG shareholders' equity	9,929,071	8,915,491
Noncontrolling interests	502,116	809,643
Total equity	10,431,187	9,725,134
Total liabilities and equity	272,173,152	248,780,722
Consolidated VIEs
Assets:
Cash and due from banks	6,989	1,941
Interest-bearing deposits in other banks	139,150	155,551
Call loans and funds sold	132,212	260,997
Trading account assets (including assets pledged that secured parties are permitted to sell or repledge of ¥7,355,733 million in 2023 and ¥11,722,063 million in 2024)	2,450,810	2,614,888
Investments (Note 3):
Investments	241,303	233,348
Loans, net of allowance	9,136,505	8,381,183
Other assets (Note 12)	524,395	505,636
Total assets	12,631,365	12,153,544
Liabilities and equity:
Payables under securities lending transactions (Note 28)	44,013	128,548
Other short-term borrowings (including liabilities accounted for at fair value of ¥153,044 million in 2024) (Notes 11 and 26)	247,180	187,852
Trading account liabilities	37,147	64,708
Long-term debt (including liabilities accounted for at fair value of ¥2,680,164 million in 2023, and ¥2,876,287 million in 2024) (Notes 11 and 26)	1,465,149	1,164,719
Other liabilities (Note 12)	1,069,472	1,057,384
Total liabilities	¥ 2,862,962	¥ 2,603,211

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023
Trading account assets, assets pledged that secured parties are permitted to sell or repledge	¥ 11,722,063	¥ 7,355,733
Available-for-sale securities, assets pledged that secured parties are permitted to sell or repledge	2,692,031	2,466,444
Held-to-maturity securities, assets pledged that secured parties are permitted to sell or repledge	3,767,997	1,594,501
Long-term debt, liabilities accounted for at fair value	¥ 2,876,287	¥ 2,680,164
Common stock, par value	¥ 0	¥ 0
Common stock, authorized	4,800,000,000	4,800,000,000
Common stock, issued	2,539,249,894	2,539,249,894
Treasury stock, shares	4,739,805	5,027,306
Other short term borrowings fair value	¥ 153,044

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Interest and dividend income:
Loans, including fees		¥ 2,953,217	¥ 1,960,377	¥ 957,579
Investments:
Interest		192,116	78,953	63,050
Dividends		113,808	96,237	83,589
Trading account assets		714,884	426,117	245,146
Call loans and funds sold		32,963	13,877	1,377
Receivables under resale agreements and securities borrowing transactions		739,016	307,744	36,479
Deposits in other banks		1,020,997	505,486	56,721
Total interest and dividend income		5,767,000	3,388,791	1,443,941
Interest expense:
Deposits		2,176,777	1,061,014	76,292
Trading account liabilities		174,883	101,311	59,739
Call money and funds purchased		22,167	17,308	1,093
Payables under repurchase agreements and securities lending transactions		1,716,331	671,006	40,672
Other short-term borrowings		95,704	59,314	5,623
Long-term debt		376,214	270,111	190,713
Total interest expense		4,562,076	2,180,064	374,132
Net interest income		1,204,924	1,208,727	1,069,809
Provision (credit) for credit losses (Notes 3 and 5)		47,135	93,753	214,408
Net interest income after provision (credit) for credit losses		1,157,788	1,114,974	855,401
Noninterest income (Note 24):
Fee and commission income		1,117,826	984,345	980,000
Foreign exchange gains (losses)—net (Note 25)	[1]	(19,390)	189,526	91,611
Trading account gains (losses)—net (Note 25)		390,260	(603,910)	(491,947)
Investment gains (losses)—net:
Debt securities		(6,446)	5,167	(14,777)
Equity securities		1,010,288	135,601	(60,563)
Equity in earnings (losses) of equity method investees—net	[2]	19,791	(26,999)	34,587
Gains on disposal of premises and equipment		10,128	4,920	9,943
Other noninterest income	[3],[4]	221,273	199,453	120,936
Total noninterest income		2,743,729	888,103	669,790
Noninterest expenses:
Salaries and employee benefits		803,966	694,027	669,474
General and administrative expenses		751,187	692,879	611,326
Occupancy expenses		168,473	164,603	201,987
Fee and commission expenses		239,246	202,347	203,957
Provision (credit) for credit losses on off-balance-sheet instruments		9,585	6,581	(14,819)
Other noninterest expenses		305,950	173,470	95,754
Total noninterest expenses		2,278,406	1,933,907	1,767,679
Income (loss) before income tax expense (benefit)		1,623,112	69,170	(242,488)
Income tax expense (benefit) (Note 19)		425,120	35,142	(141,017)
Net income (loss)	[5]	1,197,992	34,028	(101,471)
Less: Net income attributable to noncontrolling interests		285,519	48,037	3,251
Net income (loss) attributable to MHFG shareholders		¥ 912,473	¥ (14,009)	¥ (104,722)
Earnings per common share (Note 18):
Basic net income (loss) per common share		¥ 359.7	¥ (5.52)	¥ (41.28)
Diluted net income (loss) per common share	[6]	359.65	(5.52)	(41.28)
Dividends per common share:
Common stock		¥ 105	¥ 85	¥ 80
[1]Amounts include realized and unrealized gains and losses on both derivative instruments and nonderivative instruments. Amounts on derivative instruments include gains and losses on forward foreign exchange contracts and currency options. Amounts on nonderivative instruments include translation gains and losses related to foreign currency-denominated debt securities reported as Trading securities.[2]These amounts are revenues from contracts that do not meet the scope of ASC 606.[3]Part of these amounts are considered to be revenues from contracts that are within the scope of ASC 606.[4]These amounts include the net unrealized gains resulting from changes in fair values of structured notes that contain embedded derivatives. See Note 26 “Fair value” for further details.[5]The amounts that have been reclassified out of Accumulated other comprehensive income (loss), net of tax into net income are presented in Note 16 “Accumulated other comprehensive income (loss), net of tax.”[6]For the fiscal years ended March 31, 2022 and 2023, the performance-based plan under the stock compensation programs could potentially dilute earnings per common share but were not included in the computation of diluted earnings per common share due to their antidilutive effects. In addition, for the fiscal years ended March 31, 2022 and 2023, the computation of diluted earnings per common share did not assume exercise of stock options, as the effect of such exercise would be antidilutive due to net loss.

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Net income (loss)	[1]	¥ 1,197,992	¥ 34,028	¥ (101,471)
Other comprehensive income (loss), net of tax:
Net unrealized gains (losses) on available-for-sale securities, net of tax		33,384	(7,828)	(17,020)
Foreign currency translation adjustments, net of tax		240,944	135,849	185,298
Defined benefit plan adjustments, net of tax		75,987	68,223	(41,385)
Own credit risk adjustments, net of tax		(14,152)	13,443	(300)
Total other comprehensive income, net of tax		336,163	209,687	126,593
Total comprehensive income		1,534,155	243,715	25,122
Less: Total comprehensive income attributable to noncontrolling interests		286,498	48,442	7,846
Total comprehensive income attributable to MHFG shareholders		¥ 1,247,657	¥ 195,273	¥ 17,276
[1]The amounts that have been reclassified out of Accumulated other comprehensive income (loss), net of tax into net income are presented in Note 16 “Accumulated other comprehensive income (loss), net of tax.”

CONSOLIDATED STATEMENTS OF EQUI

CONSOLIDATED STATEMENTS OF EQUITY - JPY (¥) ¥ in Millions	Total	Common Stock	Retained Earnings	Accumulated other comprehensive income (loss)	[1]	Treasury Stock	Parent	Noncontrolling Interest
Balance at beginning of fiscal year at Mar. 31, 2021		¥ 5,826,863	¥ 2,967,385	¥ 318,114		¥ (7,124)		¥ 582,919
Purchases of treasury stock						(2,870)
Performance-based stock compensation program		(69)
Change in ownership interests in consolidated subsidiaries		(9,960)
Other		0	(309)
Disposal of treasury stock						1,652
Net income (loss) attributable to MHFG shareholders	¥ (104,722)		(104,722)
Change during year	126,593			121,998
Transactions between the MHFG Group and the noncontrolling interest shareholders								(44,651)
Dividends paid to noncontrolling interests								(18,095)
Dividends declared			(196,746)
Net income attributable to noncontrolling interests	3,251							3,251
Other								4,595
Balance at end of fiscal year at Mar. 31, 2022	9,442,231	5,816,834	2,665,608	440,112		(8,342)	¥ 8,914,212	528,019
Purchases of treasury stock						(2,315)
Performance-based stock compensation program		(256)
Change in ownership interests in consolidated subsidiaries		16,271
Other		(120)	(14)
Disposal of treasury stock						1,871
Net income (loss) attributable to MHFG shareholders	(14,009)		(14,009)
Change during year	209,687			209,283
Transactions between the MHFG Group and the noncontrolling interest shareholders								254,914
Dividends paid to noncontrolling interests								(21,732)
Dividends declared			(209,432)
Net income attributable to noncontrolling interests	48,037							48,037
Other								405
Balance at end of fiscal year at Mar. 31, 2023	9,725,134	5,832,729	2,442,153	649,395		(8,786)	8,915,491	809,643
Purchases of treasury stock						(3,384)
Performance-based stock compensation program		585
Change in ownership interests in consolidated subsidiaries		463
Other		(117)	412
Disposal of treasury stock						2,767
Net income (loss) attributable to MHFG shareholders	912,473		912,473
Change during year	336,163			335,184
Transactions between the MHFG Group and the noncontrolling interest shareholders								(575,476)
Dividends paid to noncontrolling interests								(18,549)
Dividends declared			(234,802)
Net income attributable to noncontrolling interests	285,519							285,519
Other								979
Balance at end of fiscal year at Mar. 31, 2024	¥ 10,431,187	¥ 5,833,660	¥ 3,120,236	¥ 984,578		¥ (9,403)	¥ 9,929,071	¥ 502,116
[1]The amounts that have been reclassified out of Accumulated other comprehensive income (loss), net of tax into net income are presented in Note 16 “Accumulated other comprehensive income (loss), net of tax.”

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities:
Net income (loss)	[1]	¥ 1,197,992	¥ 34,028	¥ (101,471)
Less: Net income attributable to noncontrolling interests		285,519	48,037	3,251
Net income (loss)		912,473	(14,009)	(104,722)
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization		222,714	238,997	228,397
Provision (credit) for credit losses		47,135	93,753	214,408
Investment losses (gains)—net		(1,003,842)	(140,768)	75,340
Equity in losses (earnings) of equity method investees—net	[2]	(19,791)	26,999	(34,587)
Foreign exchange losses (gains)—net		737,268	439,767	517,989
Deferred income tax expense (benefit)		165,355	(143,842)	(255,365)
Net change in trading account assets		(5,783,698)	(4,031,782)	2,386,304
Net change in trading account liabilities		270,707	4,235,704	3,634,056
Net change in loans held for sale		125,402	(72,356)	(126,804)
Net change in accrued income		(148,029)	(179,772)	4,680
Net change in accrued expenses		138,098	259,428	2,783
Other—net		875,705	294,794	(1,044,392)
Net cash provided by (used in) operating activities		(3,460,502)	1,006,913	5,498,087
Cash flows from investing activities:
Proceeds from sales of Available-for-sale securities		28,361,232	35,864,487	36,330,397
Proceeds from sales of Equity securities	[3]	2,834,790	930,586	2,526,075
Proceeds from maturities of Available-for-sale securities		39,223,805	39,537,476	39,008,678
Proceeds from maturities of Held-to-maturity securities		450,249	227,711	178,955
Purchases of Available-for-sale securities		(60,811,386)	(68,223,956)	(80,478,884)
Purchases of Held-to-maturity securities		(2,154,616)	(677,508)	(714,794)
Purchases of Equity securities	[3]	(3,406,497)	(914,215)	(2,208,196)
Proceeds from sales of loans		681,116	492,933	2,046,573
Net change in loans		(909,874)	(2,615,468)	(1,397,302)
Net change in call loans and funds sold, and receivables under resale agreements and securities borrowing transactions		(7,739,449)	1,790,227	(147,806)
Proceeds from sales of premises and equipment		13,594	9,813	18,720
Purchases of premises and equipment		(256,475)	(185,583)	(136,238)
Proceeds from sales of investments in subsidiaries (affecting the scope of consolidation)		89,522	2,872	50,699
Purchases of investments in subsidiaries (affecting the scope of consolidation)		(55,469)	(48,887)	(93,005)
Net cash provided by (used in) investing activities		(3,679,457)	6,190,488	(5,016,128)
Cash flows from financing activities:
Net change in deposits		2,466,532	5,834,904	3,589,567
Net change in call money and funds purchased, and payables under repurchase agreements and securities lending transactions		9,633,825	4,444,768	9,268
Net change in due to trust accounts		(503,770)	359,135	9,454
Net change in other short-term borrowings		14,167	(4,338,379)	(1,711,421)
Proceeds from issuance of long-term debt		3,061,735	4,701,954	3,004,293
Repayment of long-term debt		(2,956,548)	(2,985,756)	(2,715,054)
Proceeds from noncontrolling interests		62,780	36,924	101,755
Payments to noncontrolling interests		(67,169)	(58,811)	(80,493)
Proceeds from sales of treasury stock		2,768	1,615	874
Purchases of treasury stock		(3,384)	(2,314)	(1,927)
Dividends paid		(234,787)	(209,457)	(196,783)
Dividends paid to noncontrolling interests		(18,549)	(21,732)	(18,095)
Net cash provided by financing activities		11,457,601	7,762,851	1,991,438
Effect of exchange rate changes on cash and cash equivalents		1,803,107	857,754	966,796
Net increase in cash and cash equivalents		6,120,748	15,818,006	3,440,193
Cash and cash equivalents at beginning of fiscal year		67,992,295	52,174,289	48,734,096
Cash and cash equivalents at end of fiscal year		74,113,043	67,992,295	52,174,289
Supplemental disclosure of cash flow information:
Interest paid		4,758,832	2,030,281	274,530
Income taxes paid		287,693	133,370	164,408
Noncash investing activities:
Transfer of loans into loans held for sale		¥ 2,227	¥ 2,089	¥ 15,916
[1]The amounts that have been reclassified out of Accumulated other comprehensive income (loss), net of tax into net income are presented in Note 16 “Accumulated other comprehensive income (loss), net of tax.”[2]These amounts are revenues from contracts that do not meet the scope of ASC 606.[3]Proceeds from sales of Equity securities as well as Purchases of Equity securities include cash activity related to Other investments, the amounts of which are not significant.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Pay vs Performance Disclosure
Net Income (Loss)	¥ 912,473	¥ (14,009)	¥ (104,722)

Insider Trading Policies and Pr

Insider Trading Policies and Procedures	12 Months Ended
	Mar. 31, 2024
Insider Trading Policies and Procedures [Line Items]
Insider Trading Policies and Procedures Adopted	true

Basis of presentation and summa

Basis of presentation and summary of significant accounting policies	12 Months Ended
	Mar. 31, 2024
Basis of presentation and summary of significant accounting policies	1. Basis of presentation and summary of significant accounting policies Basis of presentation Mizuho Financial Group, Inc. (“MHFG”) is a joint stock corporation with limited liability under the laws of Japan. MHFG is a holding company for Mizuho Bank, Ltd. (“MHBK”), Mizuho Trust & Banking Co., Ltd. (“MHTB”), Mizuho Securities Co., Ltd. (“MHSC”), Asset Management One Co., Ltd. (“Asset Management One”), and other subsidiaries. MHFG, through its subsidiaries (“the MHFG Group,” or “the Group”), provides domestic and international financial services in Japan and other countries. For a discussion of the Group’s segment information, see Note 30 “Business segment information.” MHFG and its domestic subsidiaries as well as its foreign subsidiaries maintain their accounting records in accordance with the accounting standards of Japan and those standards of the countries in which they are domiciled. Certain adjustments and reclassifications have been incorporated in the accompanying consolidated financial statements to conform them to the accounting principles generally accepted in the United States of America (“U.S. GAAP”). The consolidated financial statements are stated in Japanese yen, the currency of the country in which MHFG is incorporated and principally operates. The accompanying consolidated financial statements include the accounts of MHFG and its subsidiaries. MHFG’s fiscal year ends on March 31. MHFG’s subsidiaries fiscal year end is determined by each subsidiary. If the fiscal year end of a subsidiary has more than three months discrepancy from the MHFG’s fiscal year end, the subsidiary executes provisional financial closing. For those subsidiaries where the fiscal year end is not on March 31 and where the subsidiaries do not execute provisional financial close, the effect on the MHFG Group’s consolidated financial statements of all material events through the date of each of the periods presented in the consolidated financial statements has been considered for adjustment and/or disclosure. When determining whether to consolidate investee entities, the MHFG Group performs an analysis of the facts and circumstances of the particular relationships between the MHFG Group and the investee entities as well as the ownership of voting shares. The consolidated financial statements also include the accounts of VIEs for which MHFG or its subsidiaries have been determined to be the primary beneficiary in accordance with the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 810, “Consolidation” (“ASC 810”). All significant intercompany transactions and balances have been eliminated upon consolidation. The MHFG Group accounts for investments in entities over which it has significant influence by using the equity method of accounting. These investments are included in Other investments and the Group’s proportionate share of income or loss is included in Equity in earnings (losses) of equity method investees—net. Certain comparative amounts for the prior period have been reclassified in order to conform to the current period’s presentation. Use of estimates The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect reported amounts and related disclosures. Specific areas, among others, requiring the application of management’s estimates and judgment include assumptions pertaining to the allowance for credit losses, valuation of loans held-for-sale, Definition of cash and cash equivalents For purposes of the consolidated statements of cash flows, Cash and cash equivalents consists of Cash and due from banks and Interest-bearing deposits in other banks. Cash deposited with central banks that must be maintained to meet minimum regulatory requirements is classified as restricted cash and included in Cash and cash equivalents. See Note 8 “Pledged assets and collateral” for more information on restricted cash. Translation of foreign currency financial statements and foreign currency transactions Financial statements of overseas entities are prepared using the functional currency of each entity and translated into Japanese yen for consolidation purposes. Assets and liabilities are translated using the fiscal-year-end Foreign currency translation gains and losses related to the financial statements of overseas entities of the MHFG Group, net of related income tax effects, are credited or charged directly to Foreign currency translation adjustments, a component of Accumulated other comprehensive income (loss), net of tax (“AOCI”). The tax effects of gains and losses related to the foreign currency translation of financial statements of overseas entities are not recognized unless it is apparent that the temporary differences will reverse in the foreseeable future. Assets and liabilities of domestic and overseas entities denominated in foreign currencies are remeasured into the functional currency of the respective entity at the fiscal year-end Call loans and call money Call loans and call money represent lending/borrowing, primarily through the Japanese short-term money market, to/from other financial institutions such as banks, insurance companies, and securities brokerage houses. Repurchase and resale agreements, securities lending and borrowing and other secured financing transactions Securities sold under agreements to repurchase (“repurchase agreements”), securities purchased under agreements to resell (“resale agreements”) and securities lending and borrowing transactions are accounted for as secured financing or lending transactions when control over the underlying securities is not deemed to be surrendered by the transferor. Otherwise, they are recorded as sales of securities with related forward repurchase commitments or purchases of securities with related forward resale commitments in accordance with ASC 860, “Transfers and Servicing” (“ASC 860”). Under resale agreements, securities borrowing and certain derivatives transactions, the MHFG Group receives collateral in the form of securities. In many cases, the MHFG Group is permitted to sell or repledge the securities obtained as collateral. Disclosures in respect of such collateral are presented in Note 8 “Pledged assets and collateral.” With respect to repurchase agreements, securities lending, and certain derivative transactions, counterparties may have the right to sell or repledge securities that the MHFG Group has pledged as collateral. The MHFG Group separately discloses these pledged securities in the consolidated balance sheets. The MHFG Group monitors credit exposure arising from resale agreements, repurchase agreements, securities borrowing and securities lending transactions on a regular basis, and additional collateral is obtained from or returned to counterparties, as appropriate. Trading securities and trading securities sold, not yet purchased Trading securities consist of securities and money market instruments that are bought and held principally for the purpose of reselling in the near term with the objective of generating profits on short-term fluctuations in price. Trading securities sold, not yet purchased, are securities and money market instruments sold to third parties that the MHFG Group does not own and is obligated to purchase at a later date to cover the short position. Trading securities and trading securities sold, not yet purchased, are recorded on the trade date. Trading securities and trading securities sold, not yet purchased, are recorded at fair value in the consolidated balance sheets in Trading account assets and Trading account liabilities with realized and unrealized gains and losses recorded on a trade date basis in Trading account gains (losses)—net in the consolidated statements of income. Interest and dividends on trading securities, including securities sold, not yet purchased, are recorded in Interest and dividend income or Interest expense on an accrual basis. Investments Debt securities that the MHFG Group has both the positive intent and ability to hold to maturity are classified as Held-to-maturity Available-for-sale At the end of each reporting period the MHFG Group performs a review to identify impaired available-for-sale available-for-sale first-in first-out Other investments include marketable and non-marketable non-marketable Derivative financial instruments Derivative financial instruments are bought and held principally for the purpose of market making for customers, proprietary trading in order to generate trading revenues and fee income, and also to manage the MHFG Group’s exposure to interest rate, credit and market risks related to asset and liability management. Such derivative financial instruments include interest rate, foreign currency, equity, commodity and credit default swap agreements, options, caps and floors, and financial futures and forward contracts. Derivatives bought and held for trading purposes are recorded in the consolidated balance sheets at fair value in Trading account assets and Trading account liabilities. The fair values of derivatives in a gain position and a loss position are reported as Trading account assets and Trading account liabilities, respectively. Derivatives used for asset and liability management include contracts that qualify for hedge accounting under ASC 815, “Derivatives and Hedging” (“ASC 815”). To be eligible for hedge accounting, derivative instruments must be highly effective in achieving offsetting changes in fair values or variable cash flows of the hedged items attributable to the particular risk being hedged. All qualifying hedging derivatives are valued at fair value and included in Trading account assets or Trading account liabilities. Derivatives that do not qualify for hedge accounting under ASC 815 are treated as trading positions and are accounted for as such. The fair value amounts recognized for all derivatives are presented on a gross basis and not offset against the amounts recognized for the right to reclaim cash collateral or the obligation to return cash collateral under the master netting agreement with the same counterparty. The fair values of derivative financial instruments are determined based on quoted market prices or broker-dealer quotes, if available. If not available, the fair values are estimated using quoted market prices for similar instruments, option or binomial pricing models or a present value cash flow analysis, utilizing current observable market information, where available. In determining the fair values, the Group considers various factors such as exchange or over-the-counter Changes in the fair values of all derivatives are recorded in earnings, except for derivatives qualifying as net investment hedges under ASC 815 which are recorded in AOCI. The changes in the fair values of all derivatives relating to foreign currency exchange rates are included in Foreign exchange gains (losses)—net and Trading account gains (losses)—net. Other elements of the changes in the fair values, including interest rate, equity and credit related components, except these of certain credit derivatives hedging the credit risk in the corporate loan portfolio, are recognized in Trading account gains (losses)—net. The net gain (loss) resulting from changes in the fair values of certain credit derivatives where the Group purchases protection to mitigate its credit risk exposure related to its corporate loan portfolio is recorded in Other noninterest income (expenses). Certain financial and hybrid instruments often contain embedded derivative instruments that possess implicit or explicit contract terms similar to those of a derivative instrument. Such derivative instruments are required to be fair-valued separately from the host contracts if they meet the bifurcation criteria of an embedded derivative. Such criteria include that the entire instrument is not marked to market through earnings, the economic characteristics and risks of the embedded contract terms are not clearly and closely related to those of the host contract and the embedded contract terms would meet the definition of a derivative on a stand-alone basis. Loans Loans are generally carried at the principal amount adjusted for unearned income and deferred net nonrefundable loan fees and costs. Loan origination fees, net of certain direct origination costs, are deferred and recognized over the contractual life of the loan as an adjustment of yield using a method that approximates the interest method. Interest income on performing loans is accrued and credited to income as it is earned. Unearned income and discounts or premiums on purchased loans are deferred and recognized over the life of the loan using a method that approximates the interest method. Loans are considered nonaccrual when, based on current information and events, it is probable that the MHFG Group will be unable to collect all the scheduled payments of principal and interest when due according to the contractual terms of the loans. Factors considered by management in determining if a loan is nonaccrual include delinquency status and the ability of the debtor to make payments of the principal and interest when due. Nonaccrual loans include loans past due for 90 days or more and modified loans to borrowers experiencing financial difficulty. The majority of nonaccrual loans have no contractual delinquency due to interest reductions and/or postponement of principal and interest. In case loans are designated as nonaccrual loans, interest accruals and the amortization of net origination fees are suspended and capitalized interest is written off. Cash received on nonaccrual loans is accounted for as a reduction of the loan principal if the ultimate collectability of the principal amount is in doubt, otherwise, as interest income. Loans are not restored to accrual status until interest and principal payments are current and future payments are reasonably assured. Nonaccrual loans are restored to accrual loans and accrual status, when the MHFG Group determines that the borrower poses no concerns regarding current certainty of debt fulfillment. In general, such determination is made if the borrower qualifies for an obligor rating of E2 or above and is not classified as a special attention obligor. With respect to modified loans to borrowers experiencing financial difficulty, in general, such loans are restored to accrual loans, and accrual status, when the borrower qualifies for an obligor rating of D or above. See Note 4 “Loans” for the definitions of obligor ratings. Loans that have been identified for sale are classified as loans held for sale within Other assets and are accounted for at the lower of cost or fair value on an individual loan basis, with valuation changes recorded in Other noninterest income and expenses. If management decides to retain certain loans held for sale for the foreseeable future or until maturity or payoff, such items are transferred to Loans at the lower of cost or fair value. Financial instruments—current expected credit losses (“CECL”) CECL established a single allowance framework for all financial assets measured at amortized cost and certain off-balance-sheet available-for-sale Allowance and provision (credit) for credit losses on loans Each reporting period, the MHFG Group makes adjustments to the allowance for credit losses on loans through Provision (credit) for credit losses in the consolidated statements of income. Loan principal that management judges to be uncollectible, based on detailed loan reviews and a credit quality assessment, is charged off against the allowance for credit losses on loans. In general, the Group charges off loans when the Group determines that the obligor should be classified as substantially bankrupt or bankrupt. See Note 4 “Loans” for the definitions of obligor categories. Obligors in the retail portfolio segment are generally determined to be substantially bankrupt when they are past due for more than six months, and as for obligors in the corporate portfolio segment, the Group separately monitors the credit quality of each obligor without using time-based triggers. The MHFG Group maintains an appropriate allowance for credit losses on loans to represent management’s estimate of the expected credit losses in the Group’s loan portfolio. Management evaluates the appropriateness of the allowance for credit losses on loans semi-annually. The allowance considers expected credit losses over the remaining expected lives of the applicable instruments. The expected life of each instrument is determined by considering expected prepayments, contractual terms and cancellation features. The allowance for credit losses involves significant judgments on a number of matters including expectations of future economic conditions, assignment of obligor ratings, valuation of collateral, and the development of qualitative adjustments. When determining expected credit losses, a single forward-looking macroeconomic scenario is considered over a reasonable and supportable forecast period. This forward-looking macroeconomic scenario is in line with the scenario used for the Group’s business plan. If the scenarios are not reflective of management’s expectations, adjustments may be made to the scenarios. After the forecast period, the Group reverts to long-term historical loss experience with a certain graduated transition period, to estimate losses over the remaining lives of financial assets measured at amortized cost and certain off-balance-sheet In terms of the internal risk ratings, for the corporate portfolio segment, the credit quality review process and the credit rating process serve as the basis for determining the allowance for credit losses on loans. Through such processes, loans are categorized into groups to reflect the probability of default, whereby the MHFG Group’s management assesses the ability of borrowers to service their debt, taking into consideration current financial information, ability to generate cash, historical payment experience, analysis of relevant industry segments and current trends. For the retail portfolio segment, the different categories of past due status of loans are primarily utilized in the credit quality review and the credit rating processes as the basis for determining the allowance for credit losses on loans. In general, the MHFG Group estimates expected credit losses collectively on the loans in the case of normal and watch obligors, considering the risk associated with a particular pool and the probability that the exposures within the pool will deteriorate or default. The allowance for credit losses on nonaccrual loans generally includes the allowance for those loans that were individually evaluated for expected credit losses. See Note 4 “Loans” for the definitions of obligor categories and classification of nonaccrual loans. The estimation of expected credit losses that are evaluated collectively begins with a quantitative calculation that considers the likelihood of the borrower changing delinquency status or moving from one obligor category or rating to another. The quantitative calculation covers expected credit losses over an instrument’s expected life and is estimated by applying credit loss factors to the MHFG Group’s estimated exposure at default. The credit loss factors incorporate the probability of default as well as the loss given default based on the historical loss rates. To supplement the historical loss data for overseas obligors, external credit ratings such as S&P are also used to calculate the probability of default. The model and inputs used to determine credit losses on loans that are evaluated collectively are analyzed on a periodic basis by comparing the estimated values with the actual results subsequent to the balance sheet date. The MHFG Group divides its overall portfolio into domestic and foreign portfolios and categorizes the domestic portfolio into four portfolio segments according to their risk profiles: corporate, retail, sovereign, and banks and financial institutions. The corporate portfolio segment consists of loans originated primarily by MHBK and MHTB, and includes mainly business loans such as those used for working capital and capital expenditure, as well as loans for which the primary source of repayment of the obligation is income generated by the relevant assets such as project finance, asset finance and real estate finance. The corporate portfolio segment is divided into two classes based on their risk characteristics: large companies, and small and medium-sized The retail portfolio segment consists mainly of residential mortgage loans originated by MHBK, and it is divided into two classes based on their risk characteristics: housing loans and others. For the retail portfolio segment, the Japanese unemployment rate is applied as a key factor. As it pertains to modified loans to borrowers experiencing financial difficulty in the retail portfolio segment, the restructuring itself, as well as subsequent payment defaults, if any, are considered in determining obligor categories. Expected credit loss estimates also include consideration of expected cash recoveries on loans previously charged-off, The allowance recorded for individually evaluated loans is based on (1) the present value of expected future cash flows, after considering the restructuring effect and subsequent payment default with respect to modified loans to borrowers experiencing financial difficulty, discounted at the loan’s post-modification contractual effective interest rate, (2) the loan’s observable market price, or (3) the fair value of the collateral if the loan is collateral dependent. The collateral that the MHFG Group obtains for loans consists primarily of real estate. In obtaining the collateral, the Group evaluates the fair value of the collateral and its legal enforceability. The Group also performs subsequent re-evaluations The MHFG Group’s methodology for determining the appropriate allowance for credit losses on loans also considers the imprecision inherent in the methodologies used. As a result, the amounts determined under the methodologies described above could be adjusted by management to consider the potential impact of other qualitative factors which include, but are not limited to, imprecision in macroeconomic scenario assumptions and emerging risks related to changes in the environment that affect specific portfolio segments including segments impacted by the Russia-Ukraine situation. Considering internal and external factors affecting the credit quality of the portfolio, the Group incorporated the estimated impact of the Russia-Ukraine situation, interest rates hike on domestic obligors and other factors contributing to economic uncertainty into the macroeconomic scenario by using assumptions such as the future outlook of the business environment for specific portfolio segments and the current forecast for the growth rate of gross domestic product. In terms of the Russia-Ukraine situation, considering the country risk arising from the continued sanctions against Russia and the downgrading of their credit rating, the MHFG Group incorporated the estimated impact of the Russia-Ukraine situation into the macroeconomic scenario used for determining the allowance for credit losses on loans. Allowance and provision (credit) for credit losses on off-balance-sheet The MHFG Group maintains an allowance for credit losses on off-balance-sheet allowance for credit losses on off-balance-sheet off-balance-sheet Allowance and provision (credit) for credit losses on available-for-sale The MHFG Group performs periodic reviews to identify impaired securities in accordance with ASC 326. Available-for-sale available-for-sale available-for-sale Premises and equipment Premises and equipment are stated at historical cost, and depreciation and amortization are recorded over the estimated useful lives of the assets, except for leasehold improvements, which are amortized over the shorter of the estimated useful lives of the assets or the lease term. Depreciation and amortization are principally computed in accordance with the straight-line method with respect to buildings and leasehold improvements and in accordance with the declining-balance method with respect to other premises and equipment. The useful lives of premises and equipment are as follows: Years Buildings 3 to 50 Equipment and furniture 2 to 20 Regular repairs and maintenance costs that do not extend the estimated useful life of an asset are charged to expense as incurred. Upon sale or disposition of premises and equipment, the cost and related accumulated depreciation or amortization are removed from the accounts, and any gains or losses on disposal are included in Gains on disposal of premises and equipment or Occupancy expenses. Impairment of long-lived assets The MHFG Group’s long-lived assets that are held for use are reviewed periodically for events or changes in circumstances that indicate possible impairment. The Group’s impairment review is based on an undiscounted cash flow analysis of a group of assets, combined with associated liabilities, at the lowest level for which identifiable cash flows exist. Impairment occurs when the carrying value of the asset group exceeds the future undiscounted cash flows that the asset group is expected to generate. When impairment is identified, the future cash flows are then discounted to determine the estimated fair value of the asset group and an impairment charge is recorded for the difference between the carrying value and the estimated fair value of the asset group. The long-lived assets to be disposed of by sale are carried at the lower of the carrying amount or fair value, less estimated cost to sell. Software Internal and external costs incurred in connection with developing and obtaining software for internal use during the application development stage are capitalized. Such costs include salaries and benefits for employees directly involved with and who devote time to the project, to the extent such time is incurred directly on the internal use software project. The capitalization of software ceases when the software project has been substantially completed. The capitalized software is amortized on a straight-line basis over the estimated useful life, generally 5 to 10 years. Internal use software is reviewed for impairment whenever events or changes in circumstances indicate that its carrying amount may not be recoverable. Goodwill Goodwill represents the excess of the total fair value of the acquired company, which consists of the consideration transferred, the fair value of any interest in the acquiree already held by the acquirer and the fair value of any noncontrolling interest in the acquiree over the fair value of net identifiable assets acquired at the date of acquisition in a business combination. The MHFG Group accounts for goodwill in accordance with ASC 350, “Intangibles—Goodwill and Other” (“ASC 350”). Goodwill is recorded at a designated reporting unit level for the purpose of assessing impairment. Goodwill is not amortized but is tested for impairment at least annually or more often if events or circumstances indicate there may be impairment. For both the annual and interim tests, the Group has the option to either (a) perform a quantitative impairment test or (b) first perform a qualitative assessment to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount, in which case the Group would perform the quantitative test. An impairment loss is recorded to the extent the carrying amount of goodwill exceeds its estimated fair value. The estimated fair value of the reporting units is derived based on valuation techniques that the Group believes market participants would use for each of the reporting units. The Group generally determines the estimated fair value by utilizing a discounted cash flow methodology or methodologies that incorporate price-to-book Intangible assets Intangible assets having definite useful lives are amortized over their estimated useful lives on either a straight-line basis or the method that reflects the pattern in which the economic benefits of the intangible assets are consumed. Intangible assets acquired in connection with the merger of MHSC and Shinko Securities Co., Ltd. (“Shinko”) and the integration of asset management functions of DIAM Co., Ltd. (“DIAM”), MHTB, Mizuho Asset Management Co., Ltd. (“MHAM”) and Shinko Asset Management Co., Ltd. (“Shinko Asset Management”) consist primarily of customer relationship intangibles, and are amortized over weighted-average amortization periods of 16 years and 16.9 years, respectively. Intangible assets having indefinite useful lives are not amortized and are subject to impairment tests. An impairment loss is recorded to the extent that the carrying amount of the indefinite-lived intangible asset exceeds its estimated fair value. For intangible assets subject to amortization, an impairment loss is recorded if the carrying amount is not recoverable and exceeds its estimated fair value. Leases The MHFG Group, as a lessee, recognizes liabilities to make lease payments and right-of-use elected not to separate lease and non-lease right-of-use right-of-use right-of-use right-of-use Pension and other employee benefits MHFG and certain subsidiaries sponsor pension plans which provide defined benefits to retired employees and other postretirement benefit plans, including severance indemnities. Severance indemnities are amounts payable to eligible employees upon termination of employment and are payable as a lump sum. Periodic expense and accrued liabilities are computed based on the actuarial present value of benefits, net of investment returns expected from plan assets and their fair values at the balance sheet date. Net periodic expense is charged to Salaries and employee benefits. Net actuarial gains and losses that arise from differences between actual experience and assumptions are generally amortized over Stock-based compensation MHFG, MHBK, MHTB and MHSC have stock options, in the form of stock acquisition rights, for directors (excluding the outside directors) and executive officers of the respective companies (hereinafter referred to collectively as the “Directors”). In this plan (“the MHFG Group’s Stock Plan”), 100 shares of MHFG common stock shall be issued or transferred upon exercise of each of the stock acquisition rights. The exercise price is 1 yen per share. The contractual term of the stock acquisition rights is 20 years. A holder may exercise the stock acquisition rights only after the date on which such holder loses the status as a Director of MHFG, MHBK, MHTB or MHSC. In May 2015, the MHFG Group discontinued the stock option program. Thereafter, the MHFG Group has not issued any new stock options. MHFG, MHBK, MHTB and MHSC have a responsibility-based stock compensation program for Directors (“Stock Compensation I”) and a performance-based stock compensation program for Directors (“Stock Compensation II”). MHFG and certain consolidated subsidiaries introduced both responsibility-based and performance-based stock compensation program for Operating Officers (“Stock Benefit”) in July 2021. For these programs, the stock-based compensation cost is determined based on the fair value of MHFG’s common stock as of grant date. The liability related to the cash-based compensation cost is remeasured at each reporting date based on the fair value of MHFG’s common stock. For Stock Compensation I, as the program is effectively vested on the grant date, the stock-based compensation cost is recognized on the grant date. For Stock Compensation II, the stock-based compensation costs are recognized evenly over the graded-vesting period, which is three years. For Stock Benefit, the stock-based compensation costs are recognized evenly over the vesting period, which is one year. Those Stock options and Stock Compensation plans did not have a material impact on the MHFG Group’s consolidated results of operations or financial condition. Long-term debt Premiums, discounts and issuance costs of long-term debt are amortized based on a method that approximates the interest method over the respective terms of the long-term debt. Obligations under guarantees The MHFG Group provides customers with a variety of guarantees and similar arrangements, including standby letters of credit, financial and performance guarantees, credit protection, and liquidity facilities. The MHFG Group recognizes guarante

Issued accounting pronouncement

Issued accounting pronouncements	12 Months Ended
	Mar. 31, 2024
Issued accounting pronouncements	2. Issued accounting pronouncements Adopted accounting pronouncements In March 2020, the FASB issued ASU No.2020-04, No.2020-04”). No.2021-01, No.2021-01”). No.2022-06, No.2022-06”). No.2020-04 ASU No.2021-01 No.2022-06 expedient In March 2022, the FASB issued ASU No.2022-02, No.2022-02”). 310-40, 310-20-35-9 35-11 No.2022-02 No.2022-02 Accounting pronouncements issued but not yet effective as of March 31, 2024 In November 2023, the FASB issued ASU No.2023-07, No.2023-07”). No.2023-07 In December 2023, the FASB issued ASU No.2023-09, No.2023-09”). No.2023-09

Investments

Investments	12 Months Ended
	Mar. 31, 2024
Investments	3. Investments Available-for-sale held-to-maturity The amortized cost, net of allowance for credit losses, gross unrealized gains and losses, and fair value of available-for-sale held-to-maturity Amortized cost (4)(5) Gross unrealized gains Gross unrealized losses Fair value (in millions of yen) 2023 Available-for-sale Debt securities: Japanese government bonds 16,483,722 3,067 37,496 16,449,293 Japanese local government bonds 560,093 198 5,628 554,663 U.S. Treasury bonds and federal agency securities 382,990 —  7,289 375,701 Other foreign government bonds 1,309,473 661 2,261 1,307,873 Agency mortgage-backed securities (1) 532,364 1,140 11,307 522,197 Residential mortgage-backed securities 48,257 71 866 47,462 Commercial mortgage-backed securities 856,708 5,157 451 861,414 Japanese corporate bonds and other debt securities 2,100,733 13,024 4,538 2,109,219 Foreign corporate bonds and other debt securities (2) 1,005,209 2,319 1,581 1,005,947 Total 23,279,549 25,637 71,417 23,233,769 Held-to-maturity Debt securities: Japanese government bonds 799,305 2,171 1,028 800,448 Agency mortgage-backed securities (3) 1,250,802 403 136,545 1,114,660 Total 2,050,107 2,574 137,573 1,915,108 Amortized cost (4)(5) Gross unrealized gains Gross unrealized losses Fair value (in millions of yen) 2024 Available-for-sale Debt securities: Japanese government bonds 10,968,212 9,137 2,956 10,974,393 Japanese local government bonds 591,218 95 7,574 583,739 U.S. Treasury bonds and federal agency securities 147,186 118 252 147,052 Other foreign government bonds 2,044,611 1,739 1,755 2,044,595 Agency mortgage-backed securities (1) 495,057 140 18,225 476,972 Residential mortgage-backed securities 32,120 30 767 31,383 Commercial mortgage-backed securities 800,224 4,787 789 804,222 Japanese corporate bonds and other debt securities 1,817,009 21,958 5,909 1,833,057 Foreign corporate bonds and other debt securities (2) 816,421 1,713 214 817,921 Total 17,712,059 39,718 38,442 17,713,335 Held-to-maturity Debt securities: Japanese government bonds 519,397 208 7,585 512,020 Agency mortgage-backed securities (3) 3,528,150 9,213 186,460 3,350,904 Total 4,047,547 9,421 194,044 3,862,924 Notes: (1) Agency mortgage-backed securities presented in this line consist of Japanese and Foreign agency mortgage-backed securities, of which the fair values were ¥522,166 million and ¥31 million, respectively, at March 31, 2023, and ¥476,947 million and ¥26 million, respectively, at March 31, 2024. All Japanese agency mortgage-backed securities are issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise. Foreign agency mortgage-backed securities primarily consist of Government National Mortgage Association (“Ginnie Mae”) securities, which are guaranteed by the United States government. (2) Other debt securities presented in this line primarily consist of Foreign negotiable certificates of deposit (“NCDs”) and asset-backed securities (“ABS”), of which the total fair values were ¥330,365 million at March 31, 2023, and ¥209,956 million at March 31, 2024. (3) All Agency mortgage-backed securities presented in this line are Ginnie Mae securities. (4) Amortized cost, net of the allowance for credit losses, of which the amounts related to available-for-sale (5) Accrued interest receivables are excluded from amortized cost, of which the amount were ¥5,637 million at March 31, 2023, and ¥15,708 million at March 31, 2024 and included in Accrued income. Contractual maturities The amortized cost, net of allowance for credit losses, and fair value of available-for-sale held-to-maturity Amortized cost Due in one year or less Due after one year through five years Due after five years through ten years Due after ten years Total (in millions of yen) Available-for-sale Debt securities: Japanese government bonds 10,565,041 11,922 391,249 —  10,968,212 Japanese local government bonds 72,554 220,432 288,731 9,501 591,218 U.S. Treasury bonds and federal agency securities 147,186 —  —  —  147,186 Other foreign government bonds 1,513,211 526,826 3,293 1,281 2,044,611 Agency mortgage-backed securities —  —  912 494,145 495,057 Residential mortgage-backed securities —  —  —  32,120 32,120 Commercial mortgage-backed securities 12,480 545,950 241,794 —  800,224 Japanese corporate bonds and other debt securities 270,114 1,011,897 205,192 329,806 1,817,009 Foreign corporate bonds and other debt securities 463,244 240,076 92,781 20,320 816,421 Total 13,043,830 2,557,103 1,223,953 887,173 17,712,059 Held-to-maturity Debt securities: Japanese government bonds 100,005 179,850 239,542 —  519,397 Agency mortgage-backed securities —  —  —  3,528,150 3,528,150 Total 100,005 179,850 239,542 3,528,150 4,047,547 Fair value Due in one year or less Due after one year through five years Due after five years through ten years Due after ten years Total (in millions of yen) Available-for-sale Debt securities: Japanese government bonds 10,562,258 11,912 400,223 —  10,974,393 Japanese local government bonds 72,521 219,353 282,856 9,009 583,739 U.S. Treasury bonds and federal agency securities 147,052 —  —  —  147,052 Other foreign government bonds 1,512,511 527,510 3,294 1,281 2,044,595 Agency mortgage-backed securities —  —  904 476,068 476,972 Residential mortgage-backed securities —  —  —  31,383 31,383 Commercial mortgage-backed securities 12,485 547,001 244,736 —  804,222 Japanese corporate bonds and other debt securities 270,031 1,009,579 203,358 350,089 1,833,057 Foreign corporate bonds and other debt securities 463,311 240,935 92,929 20,746 817,921 Total 13,040,169 2,556,290 1,228,299 888,577 17,713,335 Held-to-maturity Debt securities: Japanese government bonds 100,213 178,440 233,367 —  512,020 Agency mortgage-backed securities —  —  —  3,350,904 3,350,904 Total 100,213 178,440 233,367 3,350,904 3,862,924 Credit losses The MHFG Group recognized allowance for credit losses on available-for-sale available-for-sale available-for-sale recognize allowance for credit losses on held-to-maturity held-to-maturity Continuous unrealized loss position The following table shows the gross unrealized losses, net of allowance for credit losses, and fair value of available-for-sale Less than 12 months 12 months or more Total Fair value Gross unrealized losses Fair value Gross unrealized losses Fair value Gross unrealized losses (in millions of yen) 2023 Available-for-sale Debt securities: Japanese government bonds 3,706,134 11,369 1,419,222 26,127 5,125,356 37,496 Japanese local government bonds 146,484 1,596 322,224 4,032 468,708 5,628 U.S. Treasury bonds and federal agency securities 65,288 765 293,149 6,524 358,437 7,289 Other foreign government bonds 475,493 674 250,130 1,587 725,623 2,261 Agency mortgage-backed securities (Note) 142,776 2,361 238,858 8,946 381,634 11,307 Residential mortgage-backed securities 16,230 265 22,017 601 38,247 866 Commercial mortgage-backed securities. 105,346 304 43,653 147 148,999 451 Japanese corporate bonds and other debt securities 1,177,725 3,775 635,289 763 1,813,014 4,538 Foreign corporate bonds and other debt securities 434,339 1,279 68,959 302 503,298 1,581 Total 6,269,815 22,388 3,293,501 49,029 9,563,316 71,417 2024 Available-for-sale Debt securities: Japanese government bonds 9,019,722 2,448 675,435 508 9,695,157 2,956 Japanese local government bonds 108,071 369 456,471 7,205 564,542 7,574 U.S. Treasury bonds and federal agency securities 113,185 252 —  —  113,185 252 Other foreign government bonds 865,375 1,196 107,238 559 972,613 1,755 Agency mortgage-backed securities (Note) 130,779 1,125 307,777 17,100 438,556 18,225 Residential mortgage-backed securities 645 —  25,220 766 25,865 767 Commercial mortgage-backed securities. 18,594 214 138,724 576 157,318 789 Japanese corporate bonds and other debt securities 314,933 893 1,217,858 5,016 1,532,791 5,909 Foreign corporate bonds and other debt securities 203,248 166 24,902 48 228,150 214 Total 10,774,551 6,663 2,953,626 31,779 13,728,177 38,442 Note: Agency mortgage-backed securities presented in this line consist of Japanese agency mortgage-backed securities, of which the fair values were ¥381,634 million at March 31, 2023, and ¥438,556 million at March 31, 2024. All Japanese agency mortgage-backed securities are issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise. Available-for-sale Realized gains and losses The following table shows the realized gains and losses on sales of available-for-sale 2022 2023 2024 (in millions of yen) Gross realized gains 12,540 22,962 34,287 Gross realized losses (40,077 ) (23,593 ) (51,384 ) Net realized gains (losses) on sales of available-for-sale (27,537 ) (631 ) (17,097 ) Equity securities Equity securities include securities which have readily determinable fair values, securities which qualify for the practical expedient to estimate fair value using the net asset value per share (or its equivalent), and securities which are without readily determinable fair values. Equity securities which have readily determinable fair values mainly consist of common stock of Japanese listed companies. Equity securities which are measured based on the net asset value per share (or its equivalent) consist of private equity and real estate funds. Equity securities without readily determinable fair values include non-marketable Net gains and losses The following table shows the details of the net gains and losses on Equity securities for the fiscal years ended March 31, 2022, 2023 and 2024: 2022 2023 2024 (in millions of yen) Net gains (losses) recognized during the period on equity securities (60,563 ) 135,601 1,010,288 Less: Net gains (losses) recognized during the period on equity securities sold during the period 17,000 29,561 235,564 Unrealized gains (losses) recognized during the reporting period on equity securities still held at the reporting period (77,563 ) 106,040   774,724 Equity securities without readily determinable fair values The following table shows carrying amounts of equity securities without readily determinable fair values, for which the measurement alternative is used, and cumulative amounts due to downward adjustments and impairments and upward adjustments, at March 31, 2022, 2023 and 2024: 2022 2023 2024 (in millions of yen) Carrying amounts at the end of the period 207,407   207,743   357,938 Downward adjustments and impairments 6,519 5,345 11,002 Upward adjustments 11,623 13,015 13,764 The following table shows amounts recognized in earnings during the period due to downward adjustments and impairments and upward adjustments for equity securities without readily determinable fair values. 2022 2023 2024 (in millions of yen) Downward adjustments and impairments   2,626     1,291     7,296 Upward adjustments 2,459 1,459 825 The MHFG Group elected to measure all equity securities without readily determinable fair values, which do not qualify for the practical expedient to estimate fair value, using the measurement alternative, which is made on an instrument-by-instrument Other investments The following table summarizes the composition of Other investments at March 31, 2023 and 2024: 2023 2024 (in millions of yen) Equity method investments 598,772 799,527 Investments held by consolidated investment companies and other 68,429 84,969 Total 667,201 884,496 Equity method investments Investments in investees over which the MHFG Group has the ability to exert significant influence are accounted for using the equity method of accounting. Such investments included marketable equity securities with carrying values of ¥268,736 million and ¥316,205 million, at March 31, 2023 and 2024, respectively. The aggregate market values of these marketable equity securities were ¥503,171 million and ¥642,663 million, respectively. The majority of aggregate market values of these marketable equity securities as of March 31, 2024 include Orient Corporation, Joint Stock Commercial Bank for Foreign Trade of Vietnam and Mizuho Leasing Company, Limited of which the MHFG Group’s proportionate share of the total outstanding common stock were 49.00%, 15.00% and 23.54%, respectively. In addition, equity method investments as of March 31, 2024 include non-marketable Investments held by consolidated investment companies The MHFG Group consolidates certain investment companies over which it has control through either ownership or other means. Investment companies are subject to specialized industry accounting which requires investments to be carried at fair value, with changes in fair value recorded in earnings. The Group maintains this specialized industry accounting for investments held by consolidated investment companies, which consist of marketable and non-marketable

Loans

Loans	12 Months Ended
	Mar. 31, 2024
Loans	4. Loans Credit quality information In accordance with the MHFG Group’s credit risk management policies, the Group uses an internal rating system that consists of credit ratings for the corporate portfolio segment and pool allocations for the retail portfolio segment as the basis of its risk management infrastructure. Credit ratings consist of obligor ratings which represent the level of credit risk of the obligor, and transaction ratings which represent the ultimate possibility of losses expected on individual loans by taking into consideration various factors such as collateral or guarantees involved. In principle, obligor ratings are applied to all obligors except those to which pool allocations are applied, and are subject to regular review at least once a year as well as special review which is required whenever the obligor’s credit standing changes. Pool allocations are applied to small loans that are less than a specified amount by pooling customers and loans with similar risk characteristics, and the risk is assessed mainly based on past due status and managed according to such pools. The Group generally reviews the appropriateness and effectiveness of the approach to obligor ratings and pool allocations once a year in accordance with predetermined policies and procedures. The Group does not record expected credit losses for accrued interest receivables because uncollectible accrued interest is reversed through interest income in a timely manner in line with the Group’s nonaccrual and past due policies for loans. The amount of accrued interest receivables included in Accrued income The Group does not believe that its exposure to any particular geographic area and business sector results in a significant concentration of credit risk. The table below presents the MHFG Group’s definition of obligor ratings used by MHBK and MHTB, and equivalent obligor ratings are determined for the other subsidiaries: Obligor category (1) (2) Obligor rating Definition Normal A Obligors whose certainty of debt fulfillment is very high, hence their level of credit risk is very low. B Obligors whose certainty of debt fulfillment poses no problems for the foreseeable future, and their level of credit risk is low. C Obligors whose certainty of debt fulfillment and their level of credit risk pose no problems for the foreseeable future. D Obligors whose current certainty of debt fulfillment poses no problems, however, their resistance to future economic environmental changes is low. Watch E1 Obligors that require observation going forward because of either minor concerns regarding their financial position, or their somewhat weak or unstable business conditions. E2 Obligors that require special observation going forward because of problems with their borrowings such as reduced or suspended interest payments, problems with debt fulfillment such as failure to make principal or interest payments, or problems with their financial position as a result of their weak or unstable business conditions. Intensive control F Obligors that are not yet bankrupt but are in financial difficulties and are deemed likely to become bankrupt in the future because of insufficient progress in implementing their management improvement plans or other measures (including obligors that are receiving ongoing support from financial institutions). Substantially bankrupt G Obligors that have not yet become legally or formally bankrupt but are substantially insolvent because they are in serious financial difficulties and are deemed to be incapable of being restructured. Bankrupt H Obligors that have become legally or formally bankrupt. Notes: (1) Special attention obligors are watch obligors with modified debt or 90 days or more delinquent debt. Loans to such obligors are considered nonaccrual. (2) The Group classifies loans to special attention, intensive control, substantially bankrupt and bankrupt obligors as nonaccrual loans. The table below presents credit quality information of loans based on the MHFG Group’s internal rating system at March 31, 2023 and 2024: Term loans by origination year 2022 2021 2020 2019 2018 Prior to 2018 Revolving Loans (2) Total (in billions of yen) 2023 Domestic: Corporate: Large companies: Normal obligors     12,277      5,993      5,384      3,994      3,065      3,670      7,517     41,900 Watch obligors excluding special attention obligors 109 46 50 58 59 33 130 485 Nonaccrual loans 153 35 61 134 99 159 339 980 Small and medium-sized Normal obligors 551 301 285 248 221 571 531 2,708 Watch obligors excluding special attention obligors 45 16 26 16 18 28 20 169 Nonaccrual loans 26 7 16 9 8 27 29 122 Retail (1) Housing Loan: Normal obligors 711 570 476 468 478 4,723 —  7,426 Watch obligors excluding special attention obligors 1 2 1 2 1 35 —  42 Nonaccrual loans 8 2 2 1 1 25 —  39 Others: Normal obligors 184 87 226 80 64 297 484 1,422 Watch obligors excluding special attention obligors 22 6 21 5 4 5 8 71 Nonaccrual loans 9 4 6 2 4 20 10 55 Sovereign: Normal obligors 1,217 54 90 91 75 328 1 1,856 Watch obligors excluding special attention obligors 8 2 —  —  —  —  —  10 Nonaccrual loans —  —  —  —  —  —  —  —  Banks and other financial institutions: Normal obligors 107 17 23 134 155 114 95 645 Watch obligors excluding special attention obligors —  —  —  —  —  —  —  —  Nonaccrual loans —  —  —  —  —  —  —  —  Total domestic 15,428 7,142 6,667 5,242 4,252 10,035 9,164 57,930 Foreign: Corporate (3) Normal obligors 15,317 3,891 2,142 1,954 1,024 1,312 6,731 32,371 Watch obligors excluding special attention obligors 228 101 192 72 43 50 58 744 Nonaccrual loans 31 19 13 18 11 32 11 135 Retail: Normal obligors 2 1 1 1 1 3 —  9 Watch obligors excluding special attention obligors —  —  —  —  —  —  —  —  Nonaccrual loans —  —  —  —  —  —  —  —  Sovereign: Normal obligors 160 188 7 32 5 2 83 477 Watch obligors excluding special attention obligors —  —  —  —  —  —  —  —  Nonaccrual loans —  —  —  1 —  —  —  1 Banks and other financial institutions: Normal obligors 1,536 265 169 91 19 4 404 2,488 Watch obligors excluding special attention obligors 8 4 4 5 —  —  —  21 Nonaccrual loans —  —  —  —  —  —  —  —  Total foreign 17,282 4,469 2,528 2,174 1,103 1,403 7,287 36,246 Total 32,710 11,611 9,195 7,416 5,355 11,438 16,451 94,176 Term loans by origination year 2023 2022 2021 2020 2019 Prior to 2019 Revolving Loans (2) Total (in billions of yen) 2024 Domestic: Corporate: Large companies: Normal obligors     13,870      5,879      4,505      4,328      2,832      4,979      7,847     44,241 Watch obligors excluding special attention obligors 186 42 37 43 184 49 172 713 Nonaccrual loans 157 65 26 61 134 167 356 967 Small and medium-sized Normal obligors 430 251 195 150 151 533 494 2,204 Watch obligors excluding special attention obligors 35 15 10 12 15 30 19 135 Nonaccrual loans 8 7 7 8 8 33 26 97 Retail (1) Housing Loan: Normal obligors 350 391 431 342 360 5,224 —  7,098 Watch obligors excluding special attention obligors —  —  —  —  —  36 —  37 Nonaccrual loans —  —  —  —  1 33 —  35 Others: Normal obligors 211 71 54 100 48 337 470 1,291 Watch obligors excluding special attention obligors 23 6 5 10 3 7 8 62 Nonaccrual loans 5 2 3 6 2 22 9 49 Sovereign: Normal obligors 1,858 47 48 92 66 321 3 2,436 Watch obligors excluding special attention obligors 8 2 1 —  —  —  —  12 Nonaccrual loans —  —  —  —  —  —  —  —  Banks and other financial institutions: Normal obligors 120 103 262 2 107 110 527 1,231 Watch obligors excluding special attention obligors —  —  —  —  —  —  —  —  Nonaccrual loans —  —  —  —  —  —  —  —  Total domestic 17,261 6,882 5,585 5,155 3,911 11,883 9,932 60,608 Foreign: Corporate (3) Normal obligors 14,106 5,488 2,589 1,028 1,128 1,028 7,706 33,073 Watch obligors excluding special attention obligors 243 83 35 161 22 57 105 705 Nonaccrual loans 60 27 2 5 2 19 13 127 Retail: Normal obligors 2 1 1 1 1 3 —  10 Watch obligors excluding special attention obligors —  —  —  —  —  —  —  —  Nonaccrual loans —  —  —  —  —  —  —  —  Sovereign: Normal obligors 319 215 117 2 4 —  29 686 Watch obligors excluding special attention obligors —  —  —  —  —  —  —  —  Nonaccrual loans —  —  —  —  —  —  —  —  Banks and other financial institutions: Normal obligors 1,674 874 193 21 2 7 448 3,219 Watch obligors excluding special attention obligors —  6 4 —  6 —  —  16 Nonaccrual loans —  —  —  —  —  —  —  —  Total foreign 16,403 6,694 2,941 1,219 1,164 1,114 8,302 37,837 Total 33,665 13,575 8,525 6,374 5,075 12,997 18,233 98,445 Notes: (1) The primary component of the retail portfolio segment is housing loans to individuals which obligor category is classified based on past due status. The trigger to reclassify obligors from normal obligors to watch obligors excluding special attention obligors is when the past due status is more than 30 days. (2) There were no significant revolving line of credit arrangements that converted to term loans during the fiscal year ended March 31, 2023 and 2024. (3) Corporate of foreign included ¥184 billion and ¥176 billion of lease receivables that were receivables arising from direct financing leasing at March 31, 2023 and 2024, respectively. The table below presents gross charge-offs recognized for the fiscal year ended March 31, 2024: March 31, 2024 2023 2022 2021 2020 2019 Prior to 2019 Revolving Loans Total (in billions of yen) Domestic: Corporate: Large companies 5 13 3     —        2 1 2 27 Small and medium-sized 1 2 —  —  —  —  2 5 Retail: Housing Loan —  —  —  —  —  2 —  2 Others 1 1 —  —  —  1 —  3 Total domestic 6 16 3 —  2 4 4 37 Foreign: Total foreign (Note) —  1 1 2 —  6 —  10 Total 7 18 3 2 2 10 4 46 Note: The majority of total foreign consist of corporate. Loans are generally carried at the principal amount adjusted for unearned income and deferred net nonrefundable loan fees and costs. Loan origination fees, net of certain direct origination costs, are deferred and recognized over the contractual life of the loan as an adjustment of yield using a method that approximates the interest method. Interest income on performing loans is accrued and credited to income as it is earned. Unearned income and discounts or premiums on purchased loans are deferred and recognized over the life of the loan using a method that approximates the interest method. Unearned income and deferred loan fees was ¥238 billion and ¥268 billion at March 31, 2023 and 2024, respectively. The Group uses, as a practical expedient, the fair value of the collateral when recording the net carrying amounts of loans and determining the allowance for credit losses of such loans, for which the repayment is expected to be provided substantially through the operation or sale of the collateral, when the borrower is experiencing financial difficulty based on the assessment as of the reporting date. As of March 31, 2024, collateral relating to these loans was primarily comprised of real estate. There were no significant changes in the extent to which collateral secures these loans during this fiscal year and no significant concentration of collateral against any portfolio segment. Nonaccrual loans The MHFG Group considers loans to be nonaccrual when it is probable that the Group will be unable to collect all the scheduled payments of principal and interest when due according to the contractual terms of the loans. The Group classifies loans to special attention, intensive control, substantially bankrupt and bankrupt obligors as nonaccrual loans. There are no loans that are 90 days past due and still accruing. The Group does not have any loans to borrowers that cause management to have serious doubts as to the ability of such borrowers to comply with the present loan repayment terms for the periods presented other than those already designated as nonaccrual loans. The table below presents nonaccrual loans information at March 31, 2023 and 2024: Amortized cost (1) Interest income recognized (2) Nonaccrual loans with an allowance Nonaccrual loans without an allowance Total nonaccrual loans (in billions of yen) 2023 Domestic: Corporate: Large companies 961 19 980 16 Small and medium-sized 103 19 122 1 Retail: Housing Loan 22 17 39 1 Others 37 18 55 1 Total domestic 1,123 73 1,196 19 Foreign: Total foreign (3) 132 4 136 4 Total 1,255 77 1,332 23 2024 Domestic: Corporate: Large companies 950 17 967 13 Small and medium-sized 86 12 97 1 Retail: Housing Loan 20 15 35 1 Others 31 18 49 1 Total domestic 1,088 61 1,149 16 Foreign: Total foreign (3) 124 3 127 4 Total 1,212 64 1,276 20 Notes: (1) Amounts represent the outstanding balances of nonaccrual loans. The MHFG Group’s policy for placing loans in nonaccrual status is consistent with the Group’s definition of nonaccrual loans. (2) Amounts represent the amount of interest income on nonaccrual loans recognized on a cash basis and included in Interest income on loans in the consolidated statements of income. (3) The majority of total foreign consist of corporate. The remaining balance of nonaccrual loans that have been partially charged off, was ¥11,314 million and ¥8,168 million as of March 31, 2023 and 2024, respectively. Loan modifications to borrowers experiencing financial difficulty The MHFG Group grants certain modifications of loans to borrowers experiencing financial difficulty. The following table presents modified loans that were determined to be TDRs during the fiscal year ended March 31, 2023: Loan forgiveness or debt to equity swaps Interest rate reduction and/or postponement of principal and/or interest Recorded investment (1) Charge-offs (in billions of yen) 2023 Domestic: Corporate: Large companies —  141 595 Small and medium-sized —  —  106 Retail: Housing Loan —  —  5 Others —  —  19 Total domestic —  141 725 Foreign: Total foreign (2) —  —  66 Total    —       141       791 Notes: (1) Amounts represent the book values of loans immediately after the restructurings. (2) The majority of total foreign consist of corporate. The following table presents loan modifications to borrowers experiencing financial difficulty by type of modification during the fiscal year ended March 31, 2024: Term (2) Interest (2) Term Principal Other Total (3)(4) (in billions of yen) 2024 Domestic: Corporate: Large companies     227      —        4       —        6     237 Small and medium-sized 34 —  2 —  —  35 Retail: Housing Loan —  —  —  —  —  —  Others 4 —  —  —  —  5 Total domestic 265 —  6 —  6 278 Foreign: Total foreign (1) 15 5 1 —  —  20 Total 280 5 6 —  6 298 Notes: (1) The majority of total foreign consist of corporate. (2) The financial effects of loan modifications, which were largely in the form of term extensions and interest rate reductions, included extending the weighted-average life of the loans by 12.1 months, and reducing the weighted-average contractual interest rate by 0.6% for the fiscal year ended March 31, 2024. (3) Commitments to lend to borrowers experiencing financial difficulty that were granted modifications were immaterial at March 31, 2024. (4) The allowance for credit losses on loans is based on macroeconomic-sensitive models that rely on historical performance and macroeconomic scenarios to forecast expected credit losses. Modifications of loans impact expected credit losses by affecting the likelihood of default. The following table presents the delinquent status of modified loans to borrowers experiencing financial difficulty, including loans that were modified during the fiscal year ended March 31, 2024: 30-59 days 60-89 days 90 days or Total past Current Total (in billions of yen) 2024 Domestic: Corporate: Large companies —  —  4 4 234 237 Small and medium-sized      —       —      —      —       35      35 Retail: Housing Loan —  —  —  —  —  —  Others —  —  —  —  5 5 Total domestic —  —  4 5 273 278 Foreign: Total foreign (Note) —  —  —  —  20 20 Total —  —  4 5 293 298 Note: The majority of total foreign consist of corporate. Payment default is deemed to occur when the loan becomes three months past due or the obligor is downgraded to the category of substantially bankrupt or bankrupt. The following table presents payment defaults which occurred during the fiscal year ended March 31, 2023 with respect to the loans modified as TDRs within the previous twelve months: Recorded investment 2023 (in billions of yen) Domestic: Corporate: Large companies 95 Small and medium-sized 1 Retail: Housing Loan 1 Others 1 Total domestic 98 Foreign: Total foreign 10 Total     108 The loans modified and subsequently defaulted during the fiscal year ended March 31, 2024 were insignificant. Age analysis of past due loans The table below presents an analysis of the age of the amortized cost basis in loans that are past due at March 31, 2023 and 2024: 30-59 days past due 60-89 days past due 90 days or more past due Total past due Current Total (in billions of yen) 2023 Domestic: Corporate: Large companies —  3 28 31 43,334 43,365 Small and medium-sized —  —  9 9 2,990 2,999 Retail: Housing Loan 14 8 13 35 7,472 7,507 Others 4 1 10 15 1,533 1,548 Sovereign —  —  —  —  1,866 1,866 Banks and other financial institutions —  —  —  —  645 645 Total domestic 18 12 60 90 57,840 57,930 Foreign: Total foreign (Note) —  —  23 23 36,223 36,246 Total 18 12 83 113 94,063 94,176 2024 Domestic: Corporate: Large companies 1 —  35 37 45,884 45,921 Small and medium-sized —  1 5 6 2,431 2,436 Retail: Housing Loan 12 7 12 31 7,139 7,170 Others 5 1 10 16 1,387 1,403 Sovereign —  —  —  —  2,447 2,447 Banks and other financial institutions —  —  —  —  1,231 1,231 Total domestic 18 9 62 89 60,519 60,608 Foreign: Total foreign (Note) —  —  20 20 37,817 37,837 Total 18 9 82 109 98,335 98,445 Note: The majority of total foreign consist of corporate. Net losses on sales of loans Net losses on sales of loans were ¥3,080 million, ¥13,436 million and ¥43,457 million for the fiscal years ended March 31, 2022, 2023 and 2024, respectively. These net losses include unrealized gains and losses on loans held for sale, representing the adjustments to the lower of cost or fair value at the end of each reporting period. The gains and losses on sales of loans are recorded in Other noninterest income and expenses, respectively.

Allowance for Credit Losses on

Allowance for Credit Losses on Loans	12 Months Ended
	Mar. 31, 2024
Allowance for credit losses on loans	5. Allowance for credit losses on loans Changes in Allowance for credit losses on loans by portfolio segment for the fiscal years ended March 31, 2022, 2023 and 2024 are shown below: Domestic Corporate Retail Sovereign Banks and other financial institutions Foreign (2) Total (in millions of yen) 2022 Balance at beginning of fiscal year 481,420 83,171 68 623 85,567 650,849 Provision (credit) for credit losses on loans 144,998 (6,895 ) (6 ) (227 ) 49,729 187,599 Charge-offs (32,530 ) (4,166 ) —  —  (23,144 ) (59,840 ) Recoveries 7,618 1,304 —  —  9,832 18,754 Net charge-offs (24,912 ) (2,862 ) —  —  (13,312 ) (41,086 ) Others (1) —  —  —  42 12,413 12,455 Balance at end of fiscal year 601,506 73,414 62 438 134,397 809,817 2023 Balance at beginning of fiscal year 601,506 73,414   62 438 134,397 809,817 Provision (credit) for credit losses on loans 51,551 (5,413 ) (9 )   432 44,287 90,848 Charge-offs (3) (153,014 ) (5,664 ) —  —  (68,772 ) (227,450 ) Recoveries 5,858 1,204 —  —  3,414 10,476 Net charge-offs (147,156 ) (4,460 ) —  —  (65,358 ) (216,974 ) Others (1) —  —  —  —  17,268 17,268 Balance at end of fiscal year 505,901 63,541 53 870 130,594 700,959 2024 Balance at beginning of fiscal year 505,901 63,541 53 870 130,594 700,959 Provision (credit) for credit losses on loans 83,702 (4,208 ) (9 ) (597 ) (26,061 ) 52,827 Charge-offs (3) (31,936 ) (4,882 ) —  —  (9,505 ) (46,323 ) Recoveries 6,049 1,338 —  —  4,561 11,948 Net charge-offs (25,887 ) (3,544 ) —  —  (4,945 ) (34,376 ) Others (1) —  —  —  —  30,660 30,660 Balance at end of fiscal year 563,716 55,790 44 273 130,249 750,071 Notes: (1) Others includes primarily foreign exchange translation. (2) The majority of total foreign consist of corporate. (3) Charge-offs decreased from ¥227,450 million for the fiscal year ended March 31, 2023 to ¥46,323 million for the fiscal year ended March 31, 2024. The decrease was due mainly to a charge-off related to a debt waiver to a domestic corporate borrower which was recognized in the fiscal year ended March 31, 2023.

Premises and equipment

Premises and equipment	12 Months Ended
	Mar. 31, 2024
Premises and equipment	6. Premises and equipment Premises and equipment at March 31, 2023 and 2024 consist of the following:   2023     2024   (in millions of yen) Land 577,755 577,026 Buildings 703,655 684,476 Equipment and furniture 378,015 393,379 Leasehold improvements 204,835 217,762 Construction in progress 44,393 47,787 Software 1,366,445 1,452,645 Total 3,275,098 3,373,076 Less: Accumulated depreciation and amortization 1,621,210 1,658,590 Premises and equipment—net 1,653,888 1,714,485 Depreciation and amortization expense for premises and equipment for the fiscal years ended March 31, 2022, 2023 and 2024 was ¥220,436 million, ¥231,291 million and ¥214,157 million, respectively. Depreciation and amortization expense related to software was reported in General and administrative expenses, and all other depreciation and amortization expense was reported in Occupancy expenses. The MHFG Group recognized impairment losses of ¥13,500 million on premises and equipment for the fiscal year ended March 31, 2022, of which ¥433 million was recorded in General and administrative expenses and ¥13,067 million was recorded in Occupancy expenses. Such losses included ¥12,976 million of impairment losses related mainly to real estate used for the entity-wide assets. This real estate is either no longer being used or the carrying amount is not recoverable. The amount of impairment losses on premises and equipment for the fiscal year ended March 31, 2023 was not significant. The amount of impairment losses on premises and equipment for the fiscal year ended March 31, 2024 was not significant.

Goodwill and intangible assets

Goodwill and intangible assets	12 Months Ended
	Mar. 31, 2024
Goodwill and intangible assets	7. Goodwill and intangible assets Goodwill The changes in Goodwill during the fiscal years ended March 31, 2022, 2023 and 2024 are as follows:   2022     2023     2024   (in millions of yen) Balance at beginning of fiscal year 92,695 92,695 92,928 Goodwill acquired (1) —  233 66,980 Foreign exchange translation —  —  4,550 Balance at end of fiscal year 92,695 92,928 164,458 Gross amount of goodwill (2) 161,993 163,209 235,563 Accumulated impairment losses 69,298 70,281 71,105 Notes: (1) For the fiscal year ended March 31, 2024, Goodwill acquired is entirely related to the acquisition of Greenhill & Co., Inc. (2) Goodwill is recorded at a designated reporting unit level for the purpose of assessing impairment. Goodwill is not allocated to the reportable segments in Note 30 “Business segment information.” Intangible assets The table below presents the gross carrying amount, accumulated amortization and net carrying amount of intangible assets at March 31, 2023 and 2024: 2023 2024 Gross carrying amount Accumulated amortization Net carrying amount Gross carrying amount Accumulated amortization Net carrying amount (in millions of yen) Intangible assets subject to amortization: Customer relationships (Note) 130,124 94,777 35,347 135,866 102,231 33,636 Other 2,883 1,408 1,475 7,696 3,641 4,055 Total 133,007 96,185 36,822 143,562 105,871 37,690 Intangible assets not subject to amortization: Total 7,859 —  7,859 7,293 —  7,293 Total 140,866 96,185 44,681 150,855 105,871 44,984 Note: Customer relationships were mainly acquired in connection with the merger of MHSC and Shinko on May 7, 2009 and the integration among asset management companies on October 1, 2016. See Note 1 “Basis of presentation and summary of significant accounting policies” for further information. For the fiscal years ended March 31, 2022, 2023 and 2024, the MHFG Group recognized ¥7,961 million, ¥7,706 million and ¥8,557 million, respectively, of amortization expense in respect of intangible assets, reported in Other noninterest expenses. The table below presents the estimated aggregate amortization expense in respect of intangible assets for the next five years: (in millions of yen) Fiscal year ending March 31: 2025 8,825 2026 7,211 2027 6,492 2028 3,526 2029 3,098

Pledged assets and collateral

Pledged assets and collateral	12 Months Ended
	Mar. 31, 2024
Pledged assets and collateral	8. Pledged assets and collateral The following amounts, by balance sheet classification, have been pledged as collateral for borrowings and for other purposes at March 31, 2023 and 2024:   2023     2024   (in billions of yen) Interest-bearing deposits in other banks 92 94 Trading account assets 7,830 12,331 Investments 12,452 15,081 Loans 8,715 8,699 Other assets 2,059 2,699 Total 31,148 38,904 The associated liabilities collateralized by the above assets at March 31, 2023 and 2024 are summarized below:   2023     2024   (in billions of yen) Deposits 988 217 Payables under repurchase agreements 10,542 17,553 Payables under securities lending transactions 721 689 Other short-term borrowings 1,003 1,803 Long-term debt 2,173 2,490 Total 15,427 22,752 The Bank of Japan (“the BOJ”) requires private depository institutions to maintain a certain amount of funds as reserves in current accounts with the BOJ, based on average deposit balances and certain other factors. There are similar reserve deposit requirements for foreign branches and subsidiaries engaged in banking businesses in foreign countries. These amounts are deemed to be restricted cash. At March 31, 2023 and 2024, the deposit amounts maintained with the BOJ and foreign central banks, which were included in Cash and due from banks and Interest-bearing deposits in other banks, were ¥64,993 billion and ¥70,593 billion, respectively. These balances included the reserve funds required to be maintained by the MHFG Group, which amounted to ¥1,701 billion and ¥1,734 billion at March 31, 2023 and 2024, respectively. At March 31, 2023 and 2024, the MHFG Group had received collateral that can be sold or repledged, with a fair value of ¥15,529 billion and ¥25,466 billion, respectively, of which ¥13,379 billion and ¥22,812 billion, respectively, was sold and repledged. Such collateral was primarily obtained in connection with resale or securities borrowing agreements, and was generally used as collateral for repurchase or securities lending agreements, or to cover short sales. This collateral received isn’t recognized on balance sheet, except for the securities received as collateral that the Group is permitted to sell or repledge in securities lending transactions where the Group acts as lender.

Deposits

Deposits	12 Months Ended
	Mar. 31, 2024
Deposits	9. Deposits The balance and remaining maturities of time deposits and certificates of deposit issued by domestic and foreign offices at March 31, 2024 are shown in the following table: Time deposits Certificates of Total (in millions of yen) Domestic offices: Due in one year or less 21,154,572 2,339,785 23,494,357 Due after one year through two years 1,121,763 121,500 1,243,263 Due after two years through three years 917,388 —  917,388 Due after three years through four years 273,448 —  273,448 Due after four years through five years 316,649 —  316,649 Due after five years 300,193 —  300,193 Total 24,084,013 2,461,285 26,545,298 Foreign offices: Due in one year or less 24,366,453 8,783,902 33,150,355 Due after one year through two years 34,381 98,670 133,051 Due after two years through three years 14,995 172,673 187,667 Due after three years through four years 211 74,003 74,214 Due after four years through five years 1 —  1 Due after five years —  —  —  Total 24,416,041 9,129,247 33,545,288 Total 48,500,053 11,590,532 60,090,586 The aggregate estimated amounts of time deposits and certificates of deposit that meet or exceed insurance limit issued by domestic and foreign offices at March 31, 2023 and 2024 are shown in the following table:   2023     2024   (in billions of yen) Domestic offices: Time deposits 13,977 17,031 Certificates of deposit 6,232 2,461 Total 20,209 19,492 Foreign offices: Time deposits 22,503 24,416 Certificates of deposit 7,556 9,129 Total 30,059 33,545 The aggregate amount of demand deposits in overdraft status that have been reclassified as loan balances at March 31, 2023 and 2024 was ¥586 billion and ¥516 billion, respectively.

Due to trust accounts

Due to trust accounts	12 Months Ended
	Mar. 31, 2024
Due to trust accounts	10. Due to trust accounts MHTB holds assets on behalf of its customers in an agent, fiduciary or trust capacity. Such trust account assets are not the MHFG Group’s proprietary assets and are managed and accounted for separately. However, the cash in individual trust accounts is often placed with MHTB for the customers’ short-term investment needs. These amounts, which MHTB owes to the trust accounts, are recorded as Due to trust accounts.

Short-term borrowings and long-

Short-term borrowings and long-term debt	12 Months Ended
	Mar. 31, 2024
Short-term borrowings and long-term debt	11. Short-term borrowings and long-term debt Short-term borrowings Short-term borrowings consist of Due to trust accounts, Call money and funds purchased, Payables under repurchase agreements and securities lending transactions, and Other short-term borrowings. Details of Other short-term borrowings at March 31, 2023 and 2024 are as follows:   2023     2024   (in millions of yen) Short-term notes issued by consolidated VIEs of asset-backed commercial paper programs (1) 41,142 89,736 Commercial paper and short-term notes issued by MHFG’s subsidiaries (1) (2) 2,218,111 1,641,988 Borrowings from the Bank of Japan 876,036 1,588,529 Other 262,040 324,659 Total  3,397,329  3,644,912 Notes: (1) Short-term notes are issued under the laws of Japan in the form of commercial paper. (2) The amounts of commercial paper and short-term notes issued by MHFG’s subsidiaries were ¥1,782,111 million and ¥436,000 million, respectively, at March 31, 2023, and ¥1,165,988 million and ¥476,000 million, respectively, at March 31, 2024. Long-term debt Long-term debt with original maturities of more than one year at March 31, 2023 and 2024 is comprised of the following:   2023     2024   (in millions of yen) Obligations under finance 6,863 21,185 Loan participation borrowings 245,176 258,201 Senior borrowings and bonds 11,245,475 12,556,710 Subordinated borrowings and bonds 3,395,509 3,441,235 Total 14,893,023 16,277,331 The following table presents the interest rates and and Interest rates (1) Maturities (2)   2023     2024   (%) (in millions of yen) Senior borrowings and bonds: fixed rate denominated in Japanese yen 0.00-6.20 Apr.2024 Jun.2051 2,819,085 3,313,535 fixed rate denominated in U.S. dollars 0.00-6.00 Apr.2024 Mar.2048 3,692,271 4,333,084 fixed rate denominated in other currencies 0.00-6.02 Apr.2024 May.2041 1,948,714 2,361,302 floating rate denominated in Japanese yen 0.00-25.00 Apr.2024 Sep.2081 569,173 509,799 floating rate denominated in U.S. dollars 0.10-17.20 Apr.2024 Apr.2068 2,058,714 1,993,666 floating rate denominated in other currencies 0.00-8.00 Apr.2024 Sep.2041 157,518 45,325 Total 11,245,475 12,556,710 Subordinated borrowings and bonds: fixed rate denominated in Japanese yen 0.39-4.26 Jun.2024 2,961,504 3,176,285 fixed rate denominated in U.S. dollars 2.56-4.35 Oct.2025 Sep.2031 434,005 264,950 Total 3,395,509 3,441,235 Total 14,640,984 15,997,945 Notes: (1) The interest rates disclosed reflect the range of contractual rates in effect at March 31, 2024. (2) Maturity information disclosed is the range of maturities at March 31, 2024. (3) None of the long-term debt issuances above are convertible to common stock. (4) Certain debt agreements permit the MHFG Group to redeem the related debt, in whole or in part, prior to maturity at the MHFG Group’s option on terms specified in the respective agreements. The following is a summary of contractual maturities of long-term debt subsequent to March 31, 2024: (in millions of yen) Fiscal year ending March 31: 2025 3,499,569 2026 926,755 2027 1,692,064 2028 1,363,547 2029 986,587 2030 and thereafter 7,808,809 Total 16,277,331

Other assets and liabilities

Other assets and liabilities	12 Months Ended
	Mar. 31, 2024
Other assets and liabilities	12. Other assets and liabilities The following table sets forth the details of other assets and liabilities at March 31, 2023 and 2024: 2023 2024 (in millions of yen) Other assets: Accounts receivable: Receivables from brokers, dealers and customers for securities transactions 4,469,286 2,278,334 Other 468,344 571,349 Collateral pledged: Collateral pledged for derivative transactions 988,881 1,406,369 Margins provided for futures contracts 183,747 264,473 Other 890,350 1,014,478 Prepaid pension cost 768,998 763,254 Right-of-use 549,668 522,936 Security deposits 83,343 83,204 Loans held for sale 228,995 103,592 Other (1) 1,069,348 1,272,162 Total 9,700,960 8,280,151 Other liabilities: Accounts payable: Payables to brokers, dealers and customers for securities transactions 1,799,116 1,049,094 Other 527,493 639,106 Guaranteed trust principal (2) 817,448 785,292 Lease liabilities 571,087 548,699 Collateral accepted: Collateral accepted for derivative transactions 1,008,083 1,382,985 Margins accepted for futures contracts 81,925 25,405 Unearned income 112,077 101,150 Other 1,399,466 1,737,267 Total 6,316,695 6,268,999 Notes: (1) The MHFG Group included premises and equipment classified as held for sale in Other. (2) Guaranteed trust principal, included in All other liabilities in the disclosure about consolidated VIEs in the accompanying balance sheets, is a liability of certain consolidated trust arrangements that meet the definition of a VIE for which the MHFG Group provides guarantees for the repayment of principal. See Note 23 “Variable interest entities and securitizations” for further discussion of the guaranteed principal money trusts.

Preferred stock

Preferred stock	12 Months Ended
	Mar. 31, 2024
Preferred Stock	13. Preferred stock The composition of preferred stock at March 31, 2022, 2023 and 2024 is as follows: 2022 2023 2024 Class of stock Authorized Issued Authorized Issued Authorized Issued (number of shares) Class XIV preferred stock 90,000,000 —  90,000,000 —  90,000,000 —  Class XV preferred stock 90,000,000 —  90,000,000 —  90,000,000 —  Class XVI preferred stock 150,000,000 —  150,000,000 —  150,000,000 —  Holders or registered pledgees of preferred stock are entitled to receive annual dividends, and distribution of residual assets of MHFG as set out above at the liquidation value per share, prior to holders of common stock but pari passu among themselves. MHFG may pay up to one-half There was no change in balance of the preferred stock in the fiscal years ended March 31, 2022, 2023 and 2024.

Common stock

Common stock	12 Months Ended
	Mar. 31, 2024
Text Block [Abstract]
Common stock	14. Common stock The following table shows the changes in the number of issued shares of common stock during the fiscal years ended March 31, 2022, 2023 and 2024: 2022 2023 2024 (shares) Balance at beginning of fiscal year 2,539,249,894 2,539,249,894 2,539,249,894 Issuance of new shares of common stock due to exercise of stock acquisition rights —  —  —  Balance at end of fiscal year 2,539,249,894 2,539,249,894 2,539,249,894

Dividends

Dividends	12 Months Ended
	Mar. 31, 2024
Text Block [Abstract]
Dividends	15. Dividends The amount available for dividends under Japan’s Companies Act is based on the amount recorded in MHFG’s non-consolidated period-end Pursuant to the Companies Act, in making a distribution of retained earnings, an entity must set aside in its legal reserve an amount equal to one-tenth one-quarter In addition to the provision that requires an appropriation for the legal reserve, the Companies Act and Japan’s Banking Act impose certain limitations on the amount available for dividends. Under the Companies Act, MHFG’s maximum amount available for dividends at March 31, 2024, was ¥2,521,140 million, based on the amount recorded in MHFG’s general books of account under Japanese GAAP. Under the Banking Act and related regulations, MHFG has to meet the minimum capital adequacy requirements. Distributions of retained earnings, which are otherwise distributable to shareholders, are restricted in order to maintain the minimum capital requirements. See Note 17 “Regulatory matters” for further discussion of regulatory capital requirements. Payment of dividends on shares of common stock is also subject to the prior payment of dividends on shares of preferred stock, if any are outstanding.

Accumulated other comprehensive

Accumulated other comprehensive income (loss), net of tax	12 Months Ended
	Mar. 31, 2024
Accumulated other comprehensive income (loss), net of tax	16. Accumulated other comprehensive income (loss), net of tax Changes in each component of AOCI for the fiscal years ended March 31, 2022, 2023 and 2024 are as follows: 2022 2023 2024 (in millions of yen) AOCI, balance at beginning of fiscal year 318,114 440,112 649,395 Net unrealized gains (losses) on available-for-sale Balance at beginning of fiscal year (8,173 ) (25,046 ) (31,084 ) Unrealized holding gains (losses) during year (35,922 ) (7,472 ) 20,972 Less: reclassification adjustments for losses (gains) included in net income 19,049 1,434 12,173 Change during year (16,873 ) (6,038 ) 33,145 Balance at end of fiscal year (25,046 ) (31,084 ) 2,061 Foreign currency translation adjustments: Balance at beginning of fiscal year (86,873 ) 94,104 227,660 Foreign currency translation adjustments during year 181,722 133,556 258,887 Less: reclassification adjustments for losses (gains) included in net income (745 ) —  (18,682 ) Change during year 180,977 133,556 240,204 Balance at end of fiscal year 94,104 227,660 467,864 Defined benefit plan adjustments: Balance at beginning of fiscal year 397,153 355,355 423,677 Unrealized gains (losses) during year (22,825 ) 86,326 97,847 Less: reclassification adjustments for losses (gains) included in net income (18,973 ) (18,004 ) (21,861 ) Change during year (41,798 ) 68,322 75,986 Balance at end of fiscal year 355,355 423,677 499,663 Own credit risk adjustments: Balance at beginning of fiscal year 16,007 15,699 29,142 Unrealized gains (losses) during year (858 ) 12,688 (15,403 ) Less: reclassification adjustments for losses (gains) included in net income 550 755 1,251 Change during year (308 ) 13,443 (14,152 ) Balance at end of fiscal year 15,699 29,142 14,990 Total other comprehensive income (loss), net of tax attributable to MHFG shareholders 121,998 209,283 335,184 AOCI, balance at end of fiscal year 440,112 649,395 984,578 The following table shows the amounts reclassified out of AOCI into net income during the fiscal year ended March 31, 2024: Before tax (1) Tax effect (2) Net of tax before allocation to noncontrolling interests Net of tax attributable to noncontrolling interests (2) Net of tax attributable to MHFG shareholders (in millions of yen) Amounts reclassified out of AOCI Affected line items in Net unrealized gains (losses) on available-for-sale (17,325 ) 5,151 (12,173 ) —  (12,173 ) Investment gains Foreign currency t 18,682 —  18,682 —  18,682 Foreign exchange Defined benefit plan 31,617 (9,759 ) 21,858 3 21,861 Salaries and Own credit risk (1,804 ) 552 (1,251 ) —  (1,251 ) Other noninterest Total 31,171 (4,056 ) 27,115 3 27,118 Notes: (1) The financial statement line item in which the amounts in the before tax column are reported in the consolidated statements of income is listed to the right of the table. (2) The financial statement line items in which the amounts in the tax effect and the net of tax attributable to noncontrolling interest columns are reported in the consolidated statements of income are Income tax expense (benefit) and Net income (loss), respectively.

Regulatory matters

Regulatory matters	12 Months Ended
	Mar. 31, 2024
Regulatory matters	17. Regulatory matters Regulatory capital requirements MHFG, MHBK, and MHTB are subject to regulatory capital requirements supervised by the Financial Services Agency in accordance with the provisions of Japan’s Banking Act and related regulations. Certain foreign banking subsidiaries are subject to regulation and control by local supervisory authorities, including central banks. Failure to meet minimum capital requirements may initiate certain mandatory actions by regulators that, if undertaken, could have a direct material effect on the MHFG Group’s consolidated financial condition and results of operations. The capital requirements and regulatory adjustments are being phased in over a transitional period as follows: March 2023 March 2024 March 2025 March 2026 Minimum Common Equity Tier 1 capital 4.5 % 4.5 % 4.5 % 4.5 % Minimum Tier 1 capital 6.0 % 6.0 % 6.0 % 6.0 % Minimum total capital 8.0 % 8.0 % 8.0 % 8.0 % Capital conservation buffer 2.5 % 2.5 % 2.5 % 2.5 % Countercyclical capital buffer (1) 0.06 % 0.09 % 0.09 % 0.09 % Additional loss absorbency requirements for G-SIBs D-SIBs (2) 1.0 % 1.0 % 1.0 % 1.0 % Minimum Leverage Ratio (3) 3.5 % 3.5 % 3.7 % 3.7 % Notes: (1) Figures assume that the countercyclical capital buffer will continue to be 0.09% after March 2024. (2) Figures assume that the additional loss absorbency requirements applied to the Group as a G-SIB D-SIB (3) The ratios disclosed above include a leverage ratio buffer required to be met at 50% of the additional loss absorbency requirements applied to the Group as a G-SIB If the capital adequacy ratio and leverage ratio of a financial institution falls below the required level, the Financial Services Agency may, depending upon the extent of capital deterioration, take certain corrective action, including requiring the financial institution to submit an improvement plan to strengthen its capital base, reduce its total assets, restrict its business operations or other actions that could have a material effect on its financial condition and results of operations. Capital adequacy ratios and leverage ratios of MHFG, MHBK, and MHTB as of March 31, 2023 and 2024 calculated in accordance with Japanese GAAP and the guidelines established by the Financial Services Agency are set forth in the following table: 2023 2024   Amount     Ratio     Amount     Ratio   (in billions of yen, except percentages) Consolidated: MHFG: Common Equity Tier 1 capital: Required (1) 5,676 8.06 5,883 8.09 Actual 8,315 11.80 9,259 12.73 Tier 1 capital: Required (1) 6,733 9.56 6,973 9.59 Actual 9,803 13.91 10,801 14.85 Total risk-based capital: Required (1) 8,142 11.56 8,428 11.59 Actual 11,306 16.05 12,314 16.93 Leverage Ratio (2) Required (3) 7,680 3.50 8,028 3.50 Actual 9,803 4.46 10,801 4.70 MHBK: Common Equity Tier 1 capital: Required 2,941 4.50 2,968 4.50 Actual 6,873 10.51 7,431 11.26 2023 2024   Amount     Ratio     Amount     Ratio   (in billions of yen, except percentages) Tier 1 capital: Required 3,922 6.00 3,957 6.00 Actual 8,356 12.78 8,973 13.60 Total risk-based capital: Required 5,229 8.00 5,276 8.00 Actual 9,769 14.94 10,400 15.76 Leverage Ratio (2) Required 6,216 3.00 6,382 3.00 Actual 8,356 4.03 8,973 4.21 MHTB: Common Equity Tier 1 capital: Required 77 4.50 74 4.50 Actual 444 25.94 476 28.98 Tier 1 capital: Required 102 6.00 98 6.00 Actual 444 25.94 476 28.98 Total risk-based capital: Required 137 8.00 131 8.00 Actual 444 25.95 476 28.99 Leverage Ratio (2) Required 125 3.00 123 3.00 Actual 444 10.61 476 11.62 Non-consolidated: MHBK: Common Equity Tier 1 capital: Required 2,751 4.50 2,716 4.50 Actual 5,981 9.78 6,273 10.39 Tier 1 capital: Required 3,668 6.00 3,621 6.00 Actual 7,450 12.18 7,805 12.93 Total risk-based capital: Required 4,891 8.00 4,828 8.00 Actual 8,853 14.48 9,185 15.21 Leverage Ratio (2) Required 5,767 3.00 5,867 3.00 Actual 7,450 3.87 7,805 3.99 MHTB: Common Equity Tier 1 capital: Required 76 4.50 70 4.50 Actual    425 25.10 446 28.60 Tier 1 capital: Required 101 6.00 93 6.00 Actual 425 25.10 446 28.60 2023 2024   Amount     Ratio     Amount     Ratio   (in billions of yen, except percentages) Total risk-based capital: Required 135 8.00 124 8.00 Actual 425 25.11 446 28.60 Leverage Ratio (2) Required 122 3.00 118 3.00 Actual 425 10.44 446 11.31 Notes: (1) The required ratios disclosed above, at March 31, 2023 and 2024, include the capital conservation buffer of 2.5%, the countercyclical capital buffer of 0.06% and 0.09%, respectively, and the additional loss absorbency requirements for G-SIBs D-SIBs (2) The required and actual amounts disclosed above at March 31, 2023 and 2024 exclude amounts of deposits to the Bank of Japan. (3) The required ratios disclosed above, at March 31, 2023 and 2024, include a leverage ratio buffer required to be met at 50% of the additional loss absorbency requirements applied to the Group as a G-SIB MHFG’s securities subsidiary in Japan is also subject to the capital adequacy requirement under Japan’s Financial Instruments and Exchange Act. Under this requirement, securities firms must maintain a minimum capital adequacy ratio of 120% calculated as a percentage of capital accounts less certain assets, as calculated using Japanese GAAP figures, against amounts equivalent to market, counterparty, and basic risks. Specific guidelines are issued as a ministerial ordinance that details the definition of essential components of the capital ratios, including capital, disallowed assets and risks, and related measures. Failure to maintain a minimum capital ratio will trigger mandatory regulatory actions. A capital ratio of less than 140% will call for regulatory reporting and a capital ratio of less than 100% may lead to a temporary suspension of all or part of the business operations and further, to the cancellation of the license to act as a securities broker and dealer. Management believes, as of each latest balance sheet date, that MHFG, MHBK, MHTB, and their securities subsidiary in Japan and foreign banking subsidiaries were in compliance with all capital adequacy requirements to which they were subject.

Earnings per common share

Earnings per common share	12 Months Ended
	Mar. 31, 2024
Earnings per common share	18. Earnings per common share The following table sets forth the computation of basic and diluted earnings per common share for the fiscal years ended March 31, 2022, 2023 and 2024: 2022 2023 2024 (in millions of yen) Net income (loss): Net income (loss) attributable to MHFG common shareholders (104,722 ) (14,009 ) 912,473 Effect of dilutive securities —  —  —  Net income (loss) attributable to common shareholders after assumed conversions (104,722 ) (14,009 ) 912,473 2022 2023 2024 (thousands of shares) Shares: Weighted average common shares outstanding 2,537,051 2,536,596 2,536,775 Effect of dilutive securities: Stock options and the common shares of MHFG under the stock compensation programs (Note) —  —  325 Weighted average common shares after assumed conversions 2,537,051 2,536,596 2,537,100 2022 2023 2024 (in yen) Earnings per common share: Basic net income (loss) per common share (41.28 ) (5.52 ) 359.70 Diluted net income (loss) per common share (Note) (41.28 ) (5.52 ) 359.65 Note: For the fiscal years ended March 31, 2022 and 2023, the performance-based plan under the stock compensation programs could potentially dilute earnings per common share but were not included in the computation of diluted earnings per common share due to their antidilutive effects. In addition, for the fiscal years ended March 31, 2022 and 2023, the computation of diluted earnings per common share did not assume exercise of stock options, as the effect of such exercise would be antidilutive due to net loss.

Income taxes

Income taxes	12 Months Ended
	Mar. 31, 2024
Income taxes	19. Income taxes Income tax expense (benefit) The following table presents the components of Income tax expense (benefit) for the fiscal years ended March 31, 2022, 2023 and 2024:   2022     2023     2024   (in millions of yen) Current:                   Domestic 42,401 22,015 36,237 Foreign 71,947 156,969 223,529 Total current tax expense 114,348 178,984 259,765 Deferred: Domestic (256,093 ) (146,721 ) 170,106 Foreign 728 2,879 (4,750 ) Total deferred tax expense (benefit) (255,365 ) (143,842 ) 165,355 Total income tax expense (benefit) (141,017 ) 35,142 425,120 The preceding table does not reflect the tax effects of items recorded directly in Equity for the fiscal years ended March 31, 2022, 2023 and 2024. The detailed amounts recorded directly in Equity are as follows:   2022     2023     2024   (in millions of yen) Net unrealized gains (losses) on available-for-sale       Unrealized gains (losses) (16,489 ) (4,276 ) 8,273 Less: reclassification adjustments 8,504 305 5,151 Total (7,985 ) (3,971 ) 13,425 Defined benefit plan adjustments: Unrealized gains (losses) (9,020 ) 37,661 42,415 Less: reclassification adjustments (7,748 ) (7,848 ) (9,759 ) Total (16,768 ) 29,813 32,655 Own credit risk adjustments: Unrealized gains (losses) 1,745 5,630 (6,590 ) Less: reclassification adjustments 271 334 552 Total 2,016 5,964 (6,038 ) Total tax effect before allocation to noncontrolling interests (22,737 ) 31,806 40,043 Reconciliation of Income tax expense (benefit) The following table shows a reconciliation of Income tax expense at the effective statutory tax rate to the actual income tax expense for the fiscal years ended March 31, 2022, 2023 and 2024: 2022 2023 2024 Effective statutory tax rate 30.62 % 30.62 % 30.62 % Income not subject to tax 4.21 (14.23 ) (0.58 ) Expenses not deductible for tax purposes (0.34 ) 1.63 0.08 Tax rate differentials of subsidiaries 3.31 (12.95 ) (0.92 ) Change in valuation allowance (6.68 ) (1) (5.95 ) (2.34 ) Change in undistributed earnings of subsidiaries (2.22 ) 8.32 0.52 Noncontrolling interest income (loss) of consolidated VIEs. (2.10 ) (15.48 ) (5.35 ) Effect of enacted change in tax rates 0.01 (0.05 ) —  Reversal of outside basis differences 50.59 (1) —  —  Foreign tax credit and payments (16.59 ) 55.14 3.80 Income excluded from taxable income of enterprise tax 2.86 (14.96 ) (1.04 ) Controlled foreign company rules (1.66 ) 2.68 0.06 Other (3.86 ) 16.04 1.34 Effective income tax rate 58.15 % 50.81 % 26.19 % Note: (1) These amounts for the fiscal year ended March 31, 2022 mainly represent the reversal of an outside basis difference related to the share buyback conducted by MHSC in response to improving the capital position and aligning to the MHFG Group’s capital policy and the related increase in the valuation allowance. Deferred tax assets and liabilities The components of net deferred tax assets at March 31, 2023 and 2024 are as follows: 2023 2024 (in millions of yen) Deferred tax assets: Allowance for credit losses 270,423 265,855 Trading securities 173,793 208,711 Lease liabilities 176,304 168,848 Derivative financial instruments 161,141 148,716 Foreign tax credit and payments (1) 54,416 124,695 Premises and equipment 53,531 46,967 Available-for-sale 13,020 —  Net operating loss carryforwards (2)(3) 168,387 149,521 Other 201,141 290,733 1,272,156 1,404,047 Valuation allowance (1)(2)(3) (198,800 ) (233,991 ) Deferred tax assets, net of valuation allowance 1,073,356 1,170,057 Deferred tax liabilities: Investments 264,147 502,589 Prepaid pension cost and accrued pension liabilities 224,173 222,408 Right-of-use 169,353 160,630 Available-for-sale securities —  404 Other 54,515 120,104 Deferred tax liabilities 712,188 1,006,135 Net deferred tax assets 361,168 163,921 Notes: (1) The amount includes ¥37,517 million and ¥99,994 million related to MHBK’s foreign tax credit carryforwards as of March 31, 2023 and 2024, respectively. The amount is fully offset by valuation allowance, and if not utilized, the amount will expire during the fiscal years ending March 31, 2026 and 2027 (2) The amount includes ¥49,393 million and ¥9,186 million related to MHSC’s net operating loss carryforwards resulting mainly from the organizational restructuring of certain foreign subsidiaries as of March 31, 2023 and 2024, respectively. The tax effect of the net operating loss carryforwards is substantially offset by ¥43,488 million and ¥4,205 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income. (3) The amount includes ¥24,978 million and ¥25,128 million related to MHFG’s net operating loss carryforwards resulting mainly from intercompany capital transactions in relation to the share buyback conducted by MHSC as of March 31, 2023 and 2024, respectively. The tax effect of the net operating loss carryforwards is fully offset by ¥24,978 million and ¥25,128 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income. Deferred tax assets and deferred tax liabilities within the same tax jurisdiction have been netted for presentation purposes in the consolidated balance sheets. As of March 31, 2024, the accumulated amount of undistributed earnings that will be indefinitely reinvested and the unrecognized deferred tax liabilities related to such subsidiaries are approximately ¥433 billion and ¥44 billion, respectively. The following table and accompanying footnotes provide a breakdown of deferred tax assets and the valuation allowance recognized in respect of net operating loss carryforwards by tax jurisdiction and by year of expiration as of March 31, 2023 and 2024: Deferred tax assets Valuation allowance Deferred tax assets, net of valuation allowance (in billions of yen) 2023 Japan (1) 89 (75 ) 14 The United States 1 —  1 The United Kingdom (2) 77 (77 ) —  Others 1 —  1 Total 168 (152 ) 16 2024 Japan (3) 56 (34 ) 22 The United States 4 —  4 The United Kingdom (2) 88 (88 ) —  Others 1 —  1 Total 150 (123 ) 26 Notes: (1) ¥49 billion of the Japan deferred tax assets of ¥89 billion is related to MHSC, which is substantially offset by a valuation allowance, and will expire during the fiscal year ending March 31, 2026. ¥25 billion of the Japan deferred tax assets of ¥89 billion is related to MHFG, which is fully offset by a valuation allowance, and will mostly expire during the fiscal year ending March 31, 2032. (2) The United Kingdom net operating loss carryforwards may be carried forward indefinitely for tax purposes. (3) ¥25 billion of the Japan deferred tax assets of ¥56 billion is related to MHFG, which is fully offset by a valuation allowance, and will mostly expire during the fiscal year ending March 31, 2032. ¥16 billion of the Japan deferred tax assets of ¥56 billion is related to MHBK and will mostly expire during the fiscal year ending March 31, 2034. Determination of valuation allowance In accordance with ASC 740, when the MHFG Group determines whether and to what extent a valuation allowance is needed, the Group considers all available evidence, both positive and negative, to estimate future taxable income. In this regard, the Group considers reversals of existing taxable temporary differences, projected future taxable income (exclusive of reversals of existing temporary differences) and qualifying tax-planning available-for-sale tax-planning available-for-sale Positive evidence includes the Group’s results of operations for the current and preceding years on an overall consolidated basis and for most of the principal subsidiaries. In particular, the strong results of operations in recent years of MHFG’s principal banking subsidiaries in Japan represent positive evidence that can be objectively verified. Negative evidence includes the existence of significant amounts of net operating loss carryforwards or cumulative losses recorded at certain entities, and the expiration of unused net operating loss carryforwards in recent years. A valuation allowance is recorded against deferred tax assets as of the balance sheet date to the extent the Group estimates it is more likely than not that sufficient future taxable income is not available to realize such deferred tax assets. As the Group did not apply a consolidated taxation system for the fiscal year ended March 31, 2021, with a few exceptions of certain subsidiaries, deferred tax assets and liabilities are calculated separately for each legal entity. The Group has applied the consolidated taxation system from the fiscal year ended March 31, 2022 and has shifted to the Japanese Group Relief System beginning with the fiscal year ended March 31, 2023. A consolidated basis for corporate income taxes results in the reporting of taxable income or loss based upon the combined profits or losses of the parent company and its wholly-owned domestic subsidiaries. Therefore, when calculating deferred tax assets and liabilities and valuation allowance as of March 31, 2021, the Group considered the effect of the change to the consolidated taxation system. Also, when calculating deferred tax assets and liabilities and valuation allowance as of March 31, 2022, the Group considered the effect of the shift to the Japanese Group Relief System. The impact of the shift to the Japanese Group Relief System was not material to the consolidated financial statements. The changes in the valuation allowance are primarily due to changes in deductible temporary differences, net operating loss carryforwards and the estimated availability of future taxable income sources. In general, a valuation allowance is recognized against deferred tax assets related to entities that have accumulated significant net operating loss carryforwards. As of March 31, 2024, the Group’s valuation allowance was primarily related to entities in Japan, the United States and the United Kingdom. The valuation allowance was partially recognized in Japan and in the United States, while the valuation allowance was fully recognized in the United Kingdom. The Group determined whether cumulative losses were recognized by aggregating pretax results for the recent three years as part of the analysis of potential indicators of negative evidence. In each tax jurisdiction, certain entities recognized a cumulative loss on the basis of the most recent three years’ pretax results as of March 31, 2024. A valuation allowance was fully recognized against the deferred tax assets if the Group determined there was no positive evidence that overcame the negative evidence. As of March 31, 2024, MHFG’s securities subsidiary in the United Kingdom recorded cumulative losses on the basis of the recent three years’ pretax results and recognized a full valuation allowance, as there was no positive evidence to overcome the negative evidence. MHFG and its principal banking subsidiaries in Japan did not record cumulative losses in the periods presented. Change in valuation allowance The following table presents a roll-forward of the valuation allowance for the fiscal years ended March 31, 2022, 2023 and 2024:   2022     2023     2024   (in millions of yen) Balance at beginning of fiscal year 129,150 163,164 198,800 Changes that directly affected Income tax expense 16,196 (4,118 ) (38,055 ) Changes that did not affect Income tax expense: Expiration of net operating loss carryforwards —  —  —  Others 17,818 39,754 73,246 Total 17,818 39,754 73,246 Balance at end of fiscal year 163,164 198,800 233,991 The increase in the fiscal year ended March 31, 2022 of ¥16,196 million in the valuation allowance that directly affected Income tax expense was primarily related to an increase of the realizability of deferred tax assets of MHFG and its subsidiaries. The increase in the fiscal year ended March 31, 2022 of ¥17,818 million in others was primarily related to an increase in the valuation allowance that is fully recognized against the MHFG Group’s net operating loss carryforwards due to tax rate increase of MHFG’s foreign subsidiary. The decrease in the fiscal year ended March 31, 2023 of ¥4,118 million in the valuation allowance that directly affected Income tax expense was primarily related to a decrease of the realizability of deferred tax assets of MHFG and its subsidiaries. The increase in the fiscal year ended March 31, 2023 of ¥39,754 million in others was primarily related to an increase in the valuation allowance that is fully recognized against the MHBK’s foreign tax credit carryforwards. The decrease in the fiscal year ended March 31, 2024 of ¥38,055 million in the valuation allowance that directly affected Income tax expense was primarily related to a decrease of the realizability of deferred tax assets of MHFG and its subsidiaries. The increase in the fiscal year ended March 31, 2024 of ¥73,246 million in others was primarily related to an increase in the valuation allowance that is fully recognized against the MHBK’s foreign tax credit carryforwards. Net operating loss carryforwards At March 31, 2024, the MHFG Group had net operating loss carryforwards totaling ¥423 billion. These carryforwards are scheduled to expire as follows: Net operating loss carryforwards (1) (3) (in billions of yen) Fiscal year ending March 31: 2025 —  2026 16 2027 3 2028 —  2029 5 2030 and thereafter (2) 399 Total 423 Notes: (1) Net operating loss carryforwards related to Japanese local taxes recorded at MHFG in the fiscal year ended March 31, 2022 in the amount of ¥500 billion (tax effected ¥24 billion) are not included in the table. The net operating loss carryforwards are fully offset by valuation allowance and will mostly expire during the fiscal year ending March 31, 2032. (2) Including the net operating loss carryforwards which may be carried forward indefinitely in the United Kingdom. (3) Net operating loss carryforwards related to Japanese local taxes recorded at MHBK in the fiscal year ended March 31, 2024 in the amount of ¥456 billion (tax effected ¥16 billion) are not included in the table. The net operating loss carryforwards will mostly expire during the fiscal year ending March 31, 2034. Uncertainty in income tax The following table is a roll-forward of unrecognized tax benefits for the fiscal years ended March 31, 2022, 2023 and 2024: 2022 2023 2024 (in millions of yen) Total unrecognized tax benefits at beginning of fiscal year 4,401 5,245 7,043 Gross amount of increases (decreases) related to positions taken during prior years (576 ) (438 ) 205 Gross amount of increases related to positions taken during the current year 954 1,748 1,080 Amount of decreases related to settlements —  —  (1,633 ) Foreign exchange translation 466 488 944 Total unrecognized tax benefits at end of fiscal year 5,245 7,043 7,639 The total amount of unrecognized tax benefits including ¥1,812 million, ¥2,286 million and ¥3,014 million of interest and penalties was ¥5,245 million, ¥7,043 million and ¥7,639 million at March 31, 2022, 2023 and 2024, respectively, which would, if recognized, affect the Group’s effective tax rate. The Group classifies interest and penalties accrued relating to unrecognized tax benefits as Income tax expense. The MHFG Group is currently subject to ongoing tax audits in some jurisdictions. The oldest years open to tax audits in Japan, the United States and the United Kingdom are 2015, 2002 and 2018, respectively. The Group does not anticipate that increases or decreases of unrecognized tax benefits within the next twelve months would have a material effect on its consolidated results of operations or financial condition.

Pension and other employee bene

Pension and other employee benefit plans	12 Months Ended
	Mar. 31, 2024
Pension and other employee benefit plans	20. Pension and other employee benefit plans Severance indemnities and pension plans MHFG and certain subsidiaries sponsor and offer their employees, other than directors and corporate auditors, contributory and non-contributory lump-sum lump-sum Certain foreign offices and subsidiaries have defined contribution plans and/or defined benefit plans, of which disclosures are combined with those for domestic benefit plans, as they are not significant and those plans don’t use significantly different assumptions. MHFG and certain subsidiaries have several defined contribution plans. The costs recognized in respect of contributions to the plans for the fiscal years ended March 31, 2022, 2023 and 2024 were ¥3,981 million, ¥7,395 million and ¥9,004 million, respectively. Pension plans are not fully integrated among subsidiaries of MHFG and plan assets are managed separately by each plan. Net periodic benefit cost and funded status The following table presents the components of net periodic benefit cost of the severance indemnities and pension plans for the fiscal years ended March 31, 2022, 2023 and 2024:   2022     2023     2024   (in millions of yen) Service cost-benefits earned during the fiscal year 33,190 30,460 28,936 I nterest costs on projected benefit obligations 5,636 6,917 9,982 Expected return on plan assets (37,051 )   (36,322 )  (34,565 )  Amortization of prior service cost (benefits) (4,820 ) (4,854 ) (4,890 ) Amortization of net actuarial loss (gain) (20,485 ) (19,453 ) (29,045 ) Special termination benefits 10,791 7,269 1,244 Loss (gain) on settlement —  —  2,210 Other —  —  3,179 Net periodic benefit cost (12,739 ) (15,983 ) (22,948 ) Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss) before-tax   2023     2024   (in millions of yen) Net actuarial gain (loss) 122,331    138,987    Amortization of net actuarial loss (gain) (19,453 ) (29,045 ) Settlement loss (gain) of net actuarial loss (gain) —  2,210 Amortization of prior service cost (benefits) (4,854 ) (4,890 ) Total recognized in other comprehensive income (loss) before-tax 98,024 107,262 Weighted-average assumptions used to determine benefit obligations and net periodic benefit cost are as follows:   2022     2023     2024   Weighted-average assumptions used to determine benefit obligations at fiscal year end: Discount rates 0.52 % 0.82 % 1.00 % Rates of increase in future compensation levels 2.00 % 2.00 % 2.00 % Interest credit rates 4.39 % 4.45 % 4.52 %   2022     2023     2024   Weighted-average assumptions used to determine net periodic benefit cost during the year: Discount rates 0.38 % 0.52 % 0.82 % Rates of increase in future compensation levels 1.80 % 2.00 % 2.00 % Expected rates of return on plan assets 1.54 % 1.72 % 1.66 % Interest credit rates 4.38 % 4.39 % 4.45 % In estimating the discount rates, the MHFG Group looks to interest rates on a portfolio of high-quality fixed-income The following table sets forth the combined funded status and amounts recognized in the accompanying consolidated balance sheets at March 31, 2023 and 2024 for the plans of MHFG and its subsidiaries: 2023 2024 (in millions of yen) Change in benefit obligations: Benefit obligations at beginning of fiscal year 1,377,739 1,287,692 Service cost 30,460 28,936 Interest cost 6,917 9,982 Plan participants’ contributions 1,053 1,026 Actuarial loss (gain) (48,856 ) (23,767 ) Foreign exchange translation 3,250 6,408 Benefits paid (55,332 ) (54,458 ) Lump-sum (27,539 ) (17,838 ) Settlement —  (19,974 ) Other —  (1,045 ) Benefit obligations at end of fiscal year 1,287,692 1,216,964 Change in plan assets: Fair value of plan assets at beginning of fiscal year 2,114,011 2,032,215 Actual return (negative return) on plan assets 92,893 140,967 Foreign exchange translation 3,158 7,204 Partial withdrawal of assets from employee retirement benefits (Note) (147,181 ) (179,437 ) Employer contributions 23,613 31,327 Plan participants’ contributions 1,053 1,026 Benefits paid (55,332 ) (54,458 ) Settlement —  (20,549 ) Other —  (1,677 ) Fair value of plan assets at end of fiscal year 2,032,215 1,956,619 Funded status 744,523 739,655 Amounts recognized in the consolidated balance sheets consist of: Prepaid pension cost 768,998 763,254 Accrued pension liability (24,475 ) (23,600 ) Net amount recognized 744,523 739,655 2023 2024 (in millions of yen) Amounts recognized in Accumulated other comprehensive income (loss) before-tax Prior service benefits (cost) 58,173 53,216 Net actuarial gain (loss) 524,571 636,790 Net amount recognized 582,744 690,007 Note: During the fiscal years ended March 31, 2023 and 2024, certain subsidiaries of MHFG partially withdrew assets from employee retirement benefit trusts, which were established for the payment of employees’ severance pay and retirement pensions. Overall, the trusts remain in overfunded status as of March 31, 2024. No gains or losses have been recognized as a result of these transactions. The aggregated accumulated benefit obligations of these plans were ¥1,287,692 million and ¥1,216,964 million, as of March 31, 2023 and 2024, respectively. The defined benefit plans generally employ a multi-variable and non-linear lump-sum The following table shows the projected benefit obligations and the fair value of plan assets for the plans of MHFG and its subsidiaries with projected benefit obligations in excess of plan assets, and the accumulated benefit obligations and the fair value of plan assets for the plans with accumulated benefit obligations in excess of plan assets at March 31, 2023 and 2024: 2023 2024 (in millions of yen) Plans with projected benefit obligations in excess of plan assets: Projected benefit obligations 29,389 27,787 Fair value of plan assets 4,914 4,187 Plans with accumulated benefit obligations in excess of plan assets: Accumulated benefit obligations 29,389 27,787 Fair value of plan assets 4,914 4,187 Note: The plans with projected benefit obligations in excess of plan assets include those with accumulated benefit obligations in excess of plan assets. Investment policies and asset allocation In managing plan assets, the MHFG Group determines the appropriate levels of risk that the Group can assume under the given circumstances to gain total returns from a long-term perspective while ensuring that sufficient funds will be available to plan participants and beneficiaries. The long-term asset allocation to each asset category such as Japanese equity securities, Japanese debt securities, foreign equity securities and foreign debt securities is determined based upon the optimal portfolio, which aims to gain total returns within the range of an acceptable level of risk from a long-term perspective. Additionally, the asset allocation is reviewed every five years, unless there are any significant changes in the circumstances such as market fluctuations. When selecting an investment in each asset category, the MHFG Group takes into consideration credit standing of an investee, concentration of credit risk to a certain investee and liquidity of a financial instrument among other things. The investments in each asset category are further diversified across funds, strategies and sectors along with other things. There is no significant investment in a single investee except Japanese government bonds. Certain subsidiaries of MHFG established employee retirement benefit trusts and transferred their assets to the trusts as plan assets. These assets are separated from the employer’s proprietary assets for the payment to the plan beneficiaries. The assets held in these trusts are primarily Japanese equity securities and have been entrusted directly to qualified trustees including trust banks. MHFG and certain subsidiaries’ target allocation for the plan assets, excluding those of the employee retirement benefit trusts, at March 31, 2024 is as follows: Asset category Asset ratio Japanese equity securities 3.00 % Japanese debt securities 32.00 % Foreign equity securities 26.00 % Foreign debt securities 24.00 % General account of life insurance companies 10.00 % Other 5.00 % Total 100.00 % Note: General account of life insurance companies is a contract with life insurance companies which guarantees payments of principal and predetermined interest payments. Fair value of plan assets The following table presents the fair value of plan assets of MHFG and its subsidiaries at March 31, 2023 and 2024, by asset class. For the detailed information on fair value measurements, including descriptions of Level 1, 2 and 3 of the fair value hierarchy and the valuation methodologies, see Note 26 “Fair value.” 2023 2024 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (in billions of yen) Japanese equity securities: Common stocks (1) 1,018 —  —  1,018 907 —  —  907 Pooled funds (2) 5 6 —  11 5 8 —  13 Japanese debt securities: Government bonds 123 —  —  123 85 —  —  85 Pooled funds (2) —  8 —  8 —  9 —  9 Other —  21 —  21 —  18 —  18 Foreign equity securities: Common stocks 94 —  —  94 152 —  —  152 Pooled funds (2) —  8 —  8 —  10 —  11 Foreign debt securities: Government bonds 173 14 —  187 148 20 —  168 Pooled funds (2) —  3 —  3 —  3 —  3 Other —  15 —  15 —  31 —  31 General account of life insurance companies (3) —  113 —  113 —  117 —  117 Other 101 (4) 5 —  106 38 (4) (6 ) —  32 Plan assets measured at net asset value (5) 325 410 Total assets at fair value 1,514 193 —  2,032 1,336 210 —  1,957 Notes: (1) This class represents equity securities held in the employee retirement benefit trusts of ¥1,018 billion and ¥907 billion carried at fair value at March 31, 2023 and 2024, respectively, which are well-diversified across industries. (2) These classes primarily include pension investment fund trusts. Investments in these classes are generally measured at fair value and can be redeemed within a short-term period upon request. (3) Investments in this class are measured at conversion value, which is equivalent to fair value. (4) Amounts primarily include cash and short-term assets carried at fair value. (5) In accordance with ASC 820, certain plan assets that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. There were no returns on and purchases and sales of Level 3 assets during the fiscal years ended March 31, 2023 and 2024. Contributions The total contribution of approximately ¥23 billion is expected to be paid to the pension plans during the fiscal year ending March 31, 2025, based on the current funded status and expected asset return assumptions. Estimated future benefit payments The following table presents forecasted benefit payments including the effect of expected future service for the fiscal years indicated: (in millions of yen) Fiscal year ending March 31: 2025 75,229 2026 75,337 2027 74,087 2028 76,580 2029 75,596 2030-2034 324,753

Derivative financial instrument

Derivative financial instruments	12 Months Ended
	Mar. 31, 2024
Derivative financial instruments	21. Derivative financial instruments The MHFG Group enters into derivative financial instruments in response to the diverse needs of customers, to manage the risk related to the assets and liabilities of the Group, as part of its asset and liability management, and for proprietary trading purposes. The Group is exposed primarily to market risk associated with interest rate, commodity, foreign currency, and equity products. Market risk arises from changes in market prices or indices, interest rates and foreign exchange rates that may result in an adverse change in the market value of the financial instrument or an increase in its funding costs. Exposure to market risk is managed by imposing position limits and monitoring procedures and by initiating hedging transactions. In addition to market risk, the Group is exposed to credit risk associated with counterparty default or nonperformance in respect of transactions. Counterparty credit risk arises when a counterparty fails to perform according to the terms and conditions of the contract and the value of the underlying collateral held, if applicable, is not sufficient to recover resulting losses. The exposure to counterparty credit risk is measured by the fair value of all derivatives and its potential exposure at the balance sheet dates. The exposure to counterparty credit risk is managed by entering into legally enforceable master netting agreements to mitigate the overall counterparty credit risk, requiring underlying collateral and guarantees based on an individual credit analysis of each obligor and evaluating the credit features of each instrument. In addition, credit approvals, limits and monitoring procedures are also imposed. Notional and fair value amounts of derivative instruments The following table summarizes the notional and fair value amounts of derivative instruments outstanding as of March 31, 2023 and 2024. The fair values of derivatives are presented on a gross basis; derivative receivables and payables are not offset. In addition, they are not offset against the amounts recognized for the right to reclaim cash collateral or the obligation to return cash collateral under master netting agreements in the consolidated balance sheets, or the table below. Fair value Derivative receivables (2) Derivative payables (2) 2023 Notional amount (1) Designated as hedges Not designated as hedges Designated as hedges Not designated as hedges (in billions of yen) Interest rate contracts 1,991,016  —  8,374  —  8,517 Foreign exchange contracts 257,392 —  4,222 —  4,013 Equity-related contracts 7,149 —  145 —  197 Credit-related contracts 22,748 —  144 —  126 Other contracts 898 —  47 —  43 Total 2,279,203 —  12,932 —  12,896 Fair value Derivative receivables (2) Derivative payables (2) 2024 Notional amount (1) Designated as hedges Not designated as hedges Designated as hedges Not designated as hedges (in billions of yen) Interest rate contracts 2,297,499 —  8,668 —  8,712 Foreign exchange contracts 300,337 —  5,612 —  5,582 Equity-related contracts 15,914 —  340 —  394 Credit-related contracts 22,969 —  214 —  180 Other contracts 1,039 —  40 —  50 Total 2,637,757 —  14,874 —  14,918 Notes: (1) Notional amount includes the sum of gross long and gross short third-party contracts. (2) Derivative receivables and payables are recorded in Trading account assets and Trading account liabilities, respectively. The MHFG Group provided and/or accepted cash collateral for derivative transactions under master netting agreements. The cash collateral, which was not offset against derivative positions, was included in Other assets and Other liabilities, respectively, of which the amounts were ¥989 billion and ¥1,008 billion at March 31, 2023, and ¥1,406 billion and ¥1,383 billion at March 31, 2024, respectively. Hedging activities In order to qualify for hedge accounting, a derivative must be considered highly effective at reducing the risk associated with the exposure being hedged. Each derivative must be designated as a hedge, with documentation of the risk management objective and strategy, including identification of the hedging instrument, the hedged item and the risk exposure, and how effectiveness is to be assessed prospectively and retrospectively. The extent to which a hedging instrument is effective at achieving offsetting changes in fair value or cash flows must be assessed at least quarterly. The MHFG Group’s hedging activities include net investment hedges. Net investment hedges The MHFG Group uses forward foreign exchange contracts and foreign currency-denominated debt instruments to protect the value of net investments in non-Japanese Derivative instruments not designated or qualifying as hedges The MHFG Group enters into the following derivative transactions that do not qualify for hedge accounting with a view to implementing risk management strategies: (1) interest-rate swap transactions for the purpose of economically managing the interest-rate risks in deposits, loans, etc., (2) currency swap transactions for the purpose of economically managing the foreign exchange risk of these assets, (3) equity-related derivatives for the purpose of economically managing the risk of stock price fluctuation involved in holding equity products, and (4) credit derivatives for the purpose of economically managing the credit risk in loans, residential mortgage-backed securities (“RMBS”), commercial mortgage-backed securities (“CMBS”), collateralized loan obligations (“CLO”) and other similar assets. Such derivatives are accounted for as trading positions. The changes in fair value of these instruments are primarily recorded in Trading account gains (losses)—net, even though they are used to mitigate or transform the risk of exposures arising from banking activities. The net gains (losses) resulting from changes in the fair value of certain credit derivatives where the Group purchases protection to mitigate its credit risk exposure, related to its corporate loan portfolio, is recorded in Other noninterest income (expenses). The following table summarizes gains and losses on derivatives not designated or qualifying as hedges during the fiscal years ended March 31, 2022, 2023 and 2024: Gains (losses) recorded in income   2022     2023     2024   (in millions of yen) Interest rate contracts (130,312 ) (508,743 ) (22,003 ) Foreign exchange contracts 145,979 317,459 387,591 Equity-related contracts 728,226 534,615 240,277 Credit-related contracts (Note) (13,877 ) (3,857 ) (3,053 ) Other contracts 7,762 59,599 (42,005 ) Total 737,778 399,073 560,806 Note: Amounts include the net gains (losses) of ¥(605) million, ¥(653) million and ¥(952) million on the credit derivatives economically managing the credit risk of loans during the fiscal years ended March 31, 2022, 2023 and 2024, respectively. Credit derivatives A credit derivative is a bilateral contract between a seller and a buyer of protection against the credit risk of a particular entity. Credit derivatives generally require that the seller of credit protection make payments to the buyer upon the occurrence of predefined credit events, which include bankruptcy, dissolution or insolvency of the referenced entity. The MHFG Group either purchases or writes protection on either a single name or a portfolio of reference credits. The Group enters into credit derivatives to help mitigate credit risk in its corporate loan portfolio and other cash positions, to take proprietary trading positions, and to facilitate client transactions. The notional amount of credit derivatives represents the maximum potential amount of future payments the seller could be required to make. If the predefined credit event occurs, the seller will generally have a right to collect on the underlying reference credit and the related cash flows, while being liable for the full notional amount of credit protection to the buyer. The Group manages credit risk associated with written protection by purchasing protection with identical or similar underlying reference credits, which substantially offsets its exposure. Thus, the notional amount is not necessarily a reliable indicator of the Group’s actual loss exposure. The following table summarizes the notional and fair value amounts of credit derivatives at March 31, 2023 and 2024: 2023 2024 Notional amount Fair value Notional amount Fair value (in billions of yen) Credit protection written: Investment grade 4,497 31 6,183 110 Non-investment 5,774 62 3,962 37 Total 10,271 93 10,145 147 Credit protection purchased 12,477 (75 ) 12,824 (114 ) Note: The rating scale is based upon either the external ratings or the internal ratings of the underlying reference credit. The lowest investment grade rating is considered to be BBB-, non-investment Non-investment The following table shows the maximum potential amount of future payments for credit protection written by expiration period at March 31, 2023 and 2024: Maximum payout/Notional amount   2023     2024   (in billions of yen) One year or less 331 1,254 After one year through five years 9,585 8,610 After five years 355 281 Total 10,271 10,145 Note: The maximum potential amount of future payments is the aggregate notional amount of the credit derivatives where the Group wrote the credit protection, and it has not been reduced by the effect of any amounts that the Group may possibly collect on the underlying assets and the related cash flows, nor netted against that of credit protection purchased. Credit-related contingent features Certain of the MHFG Group’s derivative instruments contain provisions that require the Group’s debt to maintain an investment grade credit rating from the major credit rating agencies. If the Group’s debt credit rating were to fall below investment grade, the counterparties to the derivative instruments could request immediate payment or demand immediate and ongoing full overnight collateralization on derivative instruments which are in net liability positions for the Group. The following table shows the quantitative information about derivative instruments with credit-risk-related contingent features at March 31, 2023 and 2024:   2023     2024   (in billions of yen) Aggregate fair value of derivative instruments with credit-risk-related contingent features in net liability positions 814 1,304 Collateral provided to counterparties in the normal course of business 663 1,025 Amount required to be posted as collateral or settled immediately if credit-risk-related contingent features were triggered 151 279

Commitments and contingencies

Commitments and contingencies	12 Months Ended
	Mar. 31, 2024
Commitments and contingencies	22. Commitments and contingencies Obligations under guarantees The MHFG Group provides guarantees or indemnifications to counterparties to enhance their credit standing and enable them to complete a variety of business transactions. A guarantee represents an obligation to make payments to third parties if the counterparty fails to fulfill its obligation under a borrowing arrangement or other contractual obligation. The types of guarantees under ASC 460, “Guarantees” (“ASC 460”) provided by the MHFG Group are described below. Performance guarantees Performance guarantees are issued to guarantee customers’ performance under contractual arrangements such as a tender bid on a construction project or the completion of a construction project. Guarantees on loans Guarantees on loans include obligations to guarantee the customers’ borrowing contracts. The MHFG Group is required to make payments to the guaranteed parties in the event that customers fail to fulfill obligations under the contracts. Guarantees on securities Guarantees on securities include obligations to guarantee securities, such as bonds issued by customers. Other guarantees Other guarantees include obligations to guarantee customers’ payments, such as tax payments. Guarantees for the repayment of trust principal The MHFG Group provides certain trust products with guarantees for the repayment of trust principal, e.g., loan trusts and certain jointly operated designated money trusts. Pursuant to Japanese trust-related laws, trustees are prohibited from compensating beneficiaries for any loss in the beneficial interests in each trust. However, under a special condition of the Japanese trust-related laws, trust banks as trustees are allowed to enter into an agreement to provide compensation for any loss in the principal of the trust. The MHFG Group manages and administers the trust assets to minimize exposures against losses from the guarantees for the repayment of trust principal, including writing-off Part of the trust account profits is set aside as a reserve in trust accounts to absorb losses in the trust asset portfolios in accordance with relevant Japanese laws concerning the trust business and/or trust agreements. Statutory reserves for loan trusts and reserves for jointly operated designated money trusts are calculated based on the trust principal or the balance of loans and other assets in the trust accounts. Since the probability of principal indemnification is considered to be remote, the MHFG Group had no related reserve for credit losses recorded in its consolidated financial statements. Liabilities of trust accounts The MHFG Group, as trustee, may enter into an agreement with a third party who is not the party to the relevant trust agreement to the extent necessary to handle the trust affairs for the purpose of fulfilling the objectives of the trust and, as such, the trustee shall be allowed to assume certain liabilities. Pursuant to Japanese trust-related laws, the trustee is ultimately liable to pay those liabilities out of its proprietary assets in the event that the trust assets are insufficient to cover those liabilities. The amount of trust liabilities rarely exceeds the amount of trust assets and, therefore, those liabilities are generally covered by the corresponding trust assets. To avoid the demand for payment out of the proprietary assets, the trustee can enter into a special covenant of limited liability under which the trust creditors agree to limit the trustee’s liability to the value of the trust assets and to waive the right for compulsory execution against the trustee’s proprietary assets. The MHFG Group regularly monitors the condition of trust accounts to minimize exposures against making payment. The amounts of such liabilities in the trust accounts, excluding those with the special covenant of limited liability, are presented in the tables below. Liabilities of trust accounts principally include obligations to return collateral under security lending transactions and other transactions. Derivative financial instruments Certain written options and credit default swaps are deemed guarantees pursuant to the definition of guarantees in ASC 460 if these contracts require the MHFG Group to make payments to counterparties based on changes in an underlying instrument or index that is related to an asset, a liability, or an equity security of the counterparties. The MHFG Group’s payments could involve a gross settlement or a net settlement. Because it is difficult in practice to determine whether the counterparty has the asset, the liability or the equity security relating to the underlying, the MHFG Group has decided to include all credit default swaps and written options, excluding written options outside the scope of ASC 460, in the guarantee disclosures. The MHFG Group records all guarantees and similar obligations subject to ASC 460 at fair value in the consolidated balance sheets at the inception of the guarantee. The total carrying amount of guarantees and similar obligations at March 31, 2023 and 2024 was ¥315 billion and ¥801 billion, respectively, and was included in Other liabilities and Trading account liabilities. The total includes the carrying amounts of derivatives that are deemed to be guarantees, which amounted to ¥285 billion and ¥765 billion at March 31, 2023 and 2024, respectively. The table below summarizes the remaining term and maximum potential amount of future payments by type of guarantee at March 31, 2023 and 2024. The maximum potential amount of future payments disclosed below represents the contractual amounts that could be required to be repaid in the event of the guarantees being executed, without consideration of possible recoveries under recourse provisions or from collateral held. With respect to written options included in derivative financial instruments in the table below, in theory, the MHFG Group is exposed to unlimited losses; therefore, the table shows the notional amounts of the contracts as a substitute for the maximum exposure. The MHFG Group, when necessary, requires collateral such as cash, investment securities and real estate or third-party guarantees depending on the amount of credit risk involved, and employs means such as sub-participation 2023 Maximum potential/ Amount by expiration period One year After one year through five years After (in billions of yen) Performance guarantees 3,548 1,954 1,413 181 Guarantees on loans 228 149 26 53 Guarantees on securities 82 14 68 —  Other guarantees 3,306 2,339 869 98 Guarantees for the repayment of trust principal 18 —  8 10 Liabilities of trust accounts 554 97 282 175 Derivative financial instruments 83,420 53,774 24,954 4,692 2024 Maximum potential/ Amount by expiration period One year After one year through five years After five (in billions of yen) Performance guarantees 3,896 2,390 1,305 201 Guarantees on loans 348 258 54 36 Guarantees on securities 93 42 51 —  Other guarantees 3,543 2,809 614 120 Guarantees for the repayment of trust principal 16 —  7 10 Liabilities of trust accounts 599 165 225 209 Derivative financial instruments 113,108 78,356 29,674 5,077 The table below presents the maximum potential amount of future payments of performance guarantees, guarantees on loans, guarantees on securities and other guarantees classified based on internal ratings at March 31, 2023 and 2024: 2023 2024 (in billions of yen) Investment grade 5,587 6,095 Non-investment 1,577 1,784 Total 7,164 7,879 Note: Investment grade in the internal rating scale generally corresponds to BBB- Other off-balance-sheet In addition to guarantees, the MHFG Group issues other off-balance-sheet Commitments to extend credit Commitments to extend credit are legally binding agreements to lend to customers on demand. They usually have set maturity dates. These agreements differ from guarantees in that they are generally revocable or contain provisions that enable the MHFG Group to avoid payment or reduce the amount of credit extended under certain conditions, such as the deterioration of the borrower’s financial condition or other reasonable conditions. The MHFG Group monitors the financial condition of the potential borrowers throughout the commitment period to determine whether additional collateral or changes in the terms of the commitment are necessary. Since many of these commitments to extend credit expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. Commitments to invest in securities Commitments to invest in securities include legally binding contracts to make additional contributions to investment funds, such as private equity funds in accordance with the terms of investment agreements. Commercial letters of credit Commercial letters of credit are issued in connection with customers’ trade transactions. Normally, the customers cannot receive the goods until they make payment to a bank, and therefore these commercial letters of credit are collateralized by the underlying goods. Upon issuance of commercial letters of credit, the MHFG Group monitors the credit risk associated with these transactions to determine if additional collateral is required. The table below summarizes the contractual amounts with regard to these undrawn commitments at March 31, 2023 and 2024: 2023 2024 (in billions of yen) Commitments to extend credit (Note) 100,973 115,577 Commercial letters of credit 1,336 1,778 Total 102,309 117,355 Note: Commitments to extend credit include commitments to invest in securities. Allowance for credit losses on off-balance-sheet The amounts of allowance for credit losses on off-balance-sheet Legal proceedings and investigations The MHFG Group is involved in normal collection proceedings initiated by the Group, other legal proceedings and investigations in the ordinary course of business. In accordance with ASC 450, the Group recognizes a liability for loss contingencies arising from such proceedings and investigations when a loss is probable and the loss amount or the range of the loss can be reasonably estimated. However, if a loss is reasonably possible but the range of loss is not probable and reasonably estimable, the Group does not recognize a liability but discloses the detail of such proceedings and investigations. Based on the information available as of the date of the consolidated financial statements, the Group believes that the outcome of the collection, legal proceedings and investigations will not have a significant adverse effect on the consolidated financial statements. Leases The MHFG Group is obligated under a number of lease arrangements. The Group’s lessee arrangements mainly consist of operating leases for real estate, such as office space, including its head office, and branches. Finance leases are not significant. Some of the Group’s operating leases include variable lease payments. The following table presents the consolidated balance sheet information related to operating leases as of March 31, 2023 and 2024: 2023 2024 (in millions of yen, except for remaining lease term and discount rate) Right-of-use (Note) 549,668 522,936 Lease liabilities (Note) 571,087 548,699 Weighted average: Remaining lease term 14.7 years    14.0 years Discount rate 0.66 % 0.97 % Note: Right-of-use The following table presents lease cost and supplemental information related to operating leases for the fiscal years ended March 31, 2022, 2023 and 2024: 2022 2023 2024 (in millions of yen) Lease cost (Note) 111,907 101,808 104,314 Right-of-use 51,901 65,417 52,831 Operating cash flows 101,223 86,329 83,100 Note: Lease cost for operating leases are included in Occupancy expenses on the consolidated statements of income. The Group’s variable lease costs and costs for leases with terms of twelve months or less are not significant. The following table shows future lease payments under operating leases as of March 31, 2024: As of March 31, 2024 (in millions of yen) Fiscal year ending March 31: 2025 80,982 2026 61,337 2027 49,138 2028 38,925 2029 33,301 2030 and thereafter 314,213 Total lease payments 577,895 Amount representing interest 29,196 Total lease liabilities for operating leases 548,699

Variable interest entities and

Variable interest entities and securitizations	12 Months Ended
	Mar. 31, 2024
Text Block [Abstract]
Variable interest entities and securitizations	23. Variable interest entities and securitizations Variable interest entities In the normal course of business, the MHFG Group is involved with VIEs primarily through the following types of transactions: asset-backed commercial paper/loan programs, asset-backed securitizations, investments in securitization products, investment funds, trust arrangements, structured finance, and funding vehicles. The Group consolidates certain of these VIEs, where the Group is deemed to be the primary beneficiary because it has both (1) the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and (2) the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. The Group reassesses whether it is the primary beneficiary on an ongoing basis as long as the Group has any continuing involvement with the VIE. There are also other VIEs, where the Group has determined that it is not the primary beneficiary but has significant variable interests. In evaluating the significance of the variable interests, the Group takes into consideration the extent of its involvement with each VIE, such as the seniority of its investments, the share of its holding in each tranche and the variability it expects to absorb, as well as other relevant facts and circumstances. The likelihood of loss is not necessarily relevant to the determination of significance, and therefore, “significant” does not imply that there is high likelihood of loss. The maximum exposure to loss that is discussed in this section refers to the maximum loss that the Group could possibly be required to record in its consolidated statements of income as a result of its involvement with the VIEs. This represents exposures associated with both on-balance-sheet off-balance-sheet The table below shows the consolidated assets of the MHFG Group’s consolidated VIEs as well as total assets and maximum exposure to loss for its significant unconsolidated VIEs, in which the Group has determined that its maximum exposure to loss is greater than specific thresholds or meets certain other criteria as of March 31, 2023 and 2024: Consolidated VIEs Significant unconsolidated VIEs 2023 Consolidated assets Total assets Maximum exposure to loss (in billions of yen) Asset-backed commercial paper/loan programs 3,082 —  —  Asset-backed securitizations 1,514 224 134 Investments in securitization products 387 —  —  Investment funds 2,294 3,397 845 Trust arrangements and other 4,877 —  —  Total 12,154 3,621 979 Consolidated VIEs Significant unconsolidated VIEs 2024 Consolidated assets Total assets Maximum exposure to loss (in billions of yen) Asset-backed commercial paper/loan programs 3,370 —  —  Asset-backed securitizations 1,668 175 96 Investments in securitization products 385 —  —  Investment funds 1,908 6,322 1,113 Trust arrangements and other 5,300 —  —  Total 12,631 6,497 1,209 As of March 31, 2023 and 2024, the noncontrolling interests in consolidated VIEs amounted to ¥719 billion and ¥408 billion, respectively, and are included in the MHFG Group’s equity-classified noncontrolling interests. The MHFG Group has not provided financial or other support to consolidated or unconsolidated VIEs that the Group was not previously contractually required to provide. The tables below present the carrying amounts and classification of assets and liabilities on the MHFG Group’s balance sheets that relate to its variable interests in significant unconsolidated VIEs, as of March 31, 2023 and 2024: Assets on the MHFG Group’s balance sheets related to unconsolidated VIEs: 2023 2024 (in billions of yen) Trading account assets 83 97 Investments 482 726 Loans 154 137 Total    719    960 Liabilities on the MHFG Group’s balance sheets and maximum exposure to loss related to unconsolidated VIEs: 2023 2024 (in billions of yen) Trading account liabilities 1 3 Total 1 3 Maximum exposure to loss (Note)    979  1,209 Note: This represents the maximum amount the Group could possibly be required to record in its consolidated statements of income associated with on-balance-sheet off-balance-sheet In the table above the nature of the MHFG Group’s variable interest can take different forms, as described further in the notes below. Additionally, the Group’s exposure to the obligations of VIEs is generally limited to its interest in these entities. In certain instances the Group provides undrawn commitments to the VIEs. The MHFG Group’s maximum exposure to loss presented in the table above does not include the benefit of offsetting financial instruments that are held to mitigate the risks associated with these variable interests. Furthermore, the Group’s maximum exposure to loss presented in the table above is not reduced by the amount of collateral held as part of the transaction with the VIE or any party to the VIE directly against a specific exposure to loss. Asset-backed commercial paper/loan programs The MHFG Group manages several asset-backed commercial paper/loan programs that provide its clients with off-balance-sheet Asset-backed securitizations The MHFG Group acts as an arranger of various types of structured finance schemes to meet its clients’ needs for off-balance-sheet financial asset by the client is structured to be bankruptcy remote by use of a bankruptcy remote entity, which is deemed to be a VIE because its equity holder does not have decision making rights. The Group receives fees for structuring and/or distributing the securities sold to investors. In some cases, the Group itself purchases the securities issued by the entities and/or provides loans to the VIEs. In addition, the MHFG Group establishes several single-issue and multi-issue special purpose entities that issue collateralized debt obligations (“CDO”) or CLO, synthetic CDO/CLO or other repackaged instruments to meet clients’ and investors’ financial needs. The Group also arranges securitization transactions including CMBS, RMBS and others. In these transactions, the Group acts as an underwriter, placement agent, asset manager, derivatives counterparty, and/or investor in debt and equity instruments. In these cases, the MHFG Group considers that these variable interests are not significant as the Group does not have material balance sheet or off-balance The MHFG Group manages Tender Option Bond (“TOB”) programs which are associated with trusts that hold highly-rated, fixed-rate and tax-exempt non-customer non-customer non-customer Investments in securitization products The MHFG Group invests in, among other things, various types of CDO/CLO, synthetic CDO/CLO and repackaged instruments, CMBS and RMBS arranged by third parties for the purpose of generating current income or capital appreciation, which all utilize entities that are deemed to be VIEs. By design, such investments were investment grade at issuance and held by a diverse group of investors. The potential loss amounts of the securities and the loans are generally limited to the amounts invested because the Group has no contractual involvement in such VIEs beyond its investments. Since the Group is involved in these VIEs only as an investor, the Group does not ordinarily have the power to direct the VIEs’ activities that most significantly impact the VIEs’ economic performance. Similar to the criteria noted in the asset-backed securitization section, the Group views this investment activity to be “significant” when it has a large investment share and/or provides loans to the VIEs. The Group consolidates VIEs, where the transactions are tailored by the third-party arrangers to meet the Group’s needs as a main investor, who is ultimately deemed to have the power to determine which assets are to be held by the VIEs. The Group also invests in certain beneficial interests issued by VIEs which hold real estate that the Group utilizes. In addition to these variable interests, when the Group has the power including the sole unilateral ability to liquidate the VIEs, the Group consolidates such VIEs. Investment funds The MHFG Group invests in various investment funds, including securities investment trusts, which collectively invest in equity and debt securities that include listed Japanese securities and investment grade bonds. Investment advisory companies or fund management companies, including the Group’s subsidiaries and affiliates, administer and make investment decisions about such investment funds. The Group considers that it is a “significant” variable interest when the Group’s investment share is greater than threshold. The Group consolidates certain investment funds where it is deemed to be the primary beneficiary. The MHFG Group determines whether it is the primary beneficiary by evaluating whether it has both (1) the power to make investment decisions about the investment funds and (2) the obligation to absorb losses or the right to receive benefits that could potentially be significant to the investment funds. The Group consolidates certain investment funds where it is deemed to be the primary beneficiary. Trust arrangements The MHFG Group offers a variety of asset management and administration services under trust arrangements including security investment trusts, pension trusts and trusts used in the securitization of assets originated by and transferred to third parties. The Group receives trust fees for providing services as an agent or fiduciary on behalf of beneficiaries. In these cases, the Group considers that these variable interests are not significant except for its specific involvement as noted below. With respect to guaranteed principal money trust products, the MHFG Group assumes certain risks by providing guarantees for the repayment of principal as required by the trust agreements or relevant Japanese legislation. The Group manages entrusted funds primarily through the origination of high-quality loans and other credit-related products, investing in investment grade marketable securities such as Japanese government bonds and placing cash with the Group’s subsidiary trust banks. The Group has the power to determine which assets will be held by the VIEs or to manage these assets. In addition, through the principal guarantee agreements, the Group has the obligation to absorb losses that could potentially be significant to the VIEs. Therefore, the Group consolidates such VIEs. However, the Group does not consolidate certain guaranteed principal money trusts, which invest all the entrusted funds in the Group itself, as the Group has determined that it has no variable interests. See Note 22 “Commitments and contingencies” for the balances of guaranteed trust principal that are not consolidated at March 31, 2023 and 2024. With respect to non-guaranteed non-guaranteed losses nor the right to receive benefits that could potentially be significant to the VIEs. Therefore, such trust accounts are not included in the consolidated financial statements of the Group. The MHFG Group established a trust in August 2020, which holds the Group’s housing loans and in turn issues beneficiary interests to the Group. The Group pledges the beneficiary interests as a collateral for borrowing from the Bank of Japan. In its role as a servicer, the Group has power to direct the entity’s activities that most significantly impact the entity’s economic performance by managing mortgage loans owned by a trust. The Group considers that it is a “significant” variable interest since the Group can determine which assets will be held by the VIE. In addition, through the beneficiary interest, the Group has the obligation to absorb losses and the right to receive benefits that could potentially be significant to the VIE. Therefore, the Group consolidates the VIE. Special purpose entities created for structured finance The MHFG Group is involved in real estate, commercial aircraft and other vessel and machinery and equipment financing to VIEs and financing in securitized receivable. As the Group typically only provides senior financing with credit enhanced by subordinated interests and may sometimes act as an interest rate swap counterparty, the Group has determined that it does not have the power to direct the activities of the VIEs that most significantly impact the VIEs’ economic performance, or it does not have significant variable interests. Therefore, the Group does not consolidate such VIEs. Funding Vehicles The MHFG Group established a wholly-owned off-shore Securitization The MHFG Group engages in securitization activities and securitizes mortgage loans, other loans, government and corporate securities and other types of financial assets in the normal course of business. In these securitization transactions, the Group records the transfer of a financial asset as a sale when all the accounting criteria for a sale under ASC 860 are met. These criteria are (1) the transferred financial assets are legally isolated from the Group’s creditors, (2) the transferee or beneficial interest holder has the right to pledge or exchange the transferred financial assets, and (3) the Group does not maintain effective control over the transferred financial assets. If all the criteria are not met, the transfer is accounted for as a secured borrowing. For the fiscal years ended March 31, 2022, 2023 and 2024, the MHFG Group neither made significant transfers of financial assets nor recognized significant gains or losses in securitization transactions accounted for as sales. Therefore, the Group did not have the significant assets obtained as proceeds and the significant liabilities incurred in the transfer. The Group did not recognize significant continuing involvement and retain significant interests in securitization transactions accounted for as sales as of March 31, 2023 and 2024.

Noninterest income

Noninterest income	12 Months Ended
	Mar. 31, 2024
Noninterest income	24. Noninterest income Details of Noninterest income for the fiscal years ended March 31, 2022, 2023 and 2024 are as follows: 2022 2023 2024 (in millions of yen) Fee and commission income: Securities-related business (1) 184,014 190,026 246,865 Deposits-related business (1) 15,358 15,540 15,591 Lending-related business (2) (4) 162,953 193,838 232,626 Remittance business (1) 103,979 104,201 106,762 Asset management business (1) 122,014 109,358 115,504 Trust-related business (1) 141,365 130,576 136,800 Agency business (1) 36,899 36,529 38,329 Guarantee-related business (3) 35,296 41,150 43,791 Fees for other customer services (1) 178,122 163,127 181,558 Total Fee and commission income 980,000 984,345 1,117,826 Foreign exchange gains (losses)—net (3) 91,611 189,526 (19,390 ) Trading account gains (losses)—net (2) (491,947 ) (603,910 ) 390,260 Investment gains (losses)—net: Debt securities (3) (14,777 ) 5,167 (6,446 ) Equity securities (3) (60,563 ) 135,601 1,010,288 Equity in earnings (losses) of equity method investees—net (3) 34,587 (26,999 ) 19,791 Gains on disposal of premises and equipment (3) 9,943 4,920 10,128 Other noninterest income (2) (5) 120,936 199,453 221,273 Total 669,790 888,103 2,743,729 Notes: (1) These amounts are revenues from contracts within the scope of ASC 606, “Revenue from contracts with customers” (“ASC 606”). (2) Part of these amounts are considered to be revenues from contracts that are within the scope of ASC 606. (3) These amounts are revenues from contracts that do not meet the scope of ASC 606. (4) Most of the lending-related fees such as commitment fees and arrangement fees are not within the scope of ASC 606. (5) These amounts include the net unrealized gains resulting from changes in fair values of structured notes that contain embedded derivatives. See Note 26 “Fair value” for further details. Certain Fee and commission income, Trading account gains (losses)—net and Other noninterest income outlined in the table above are considered to be revenues from contracts that are within the scope of ASC 606. The MHFG Group disaggregates Fee and commission income, which is the main part of revenues within the scope of ASC 606, by type of business or service in the table above. Fee and commission income For the MHFG Group’s accounting policy for the recognition of Fee and commission income, see Note 1 “Basis of presentation and summary of significant accounting policies.” Trust-related business fees consist of trust fees earned primarily through fiduciary asset management and administrative service and other trust-related fees, which amounted to ¥56 billion and ¥85 billion for the fiscal year ended March 31, 2022, respectively, ¥55 billion and ¥76 billion for the fiscal year ended March 31, 2023, respectively, and ¥58 billion and ¥79 billion for the fiscal year ended March 31, 2024, respectively. Trading account gains (losses)—net and Other noninterest income In addition to Fee and commission income, Trading account gains (losses)—net and Other noninterest income include certain revenues within the scope of ASC 606. Underwriting fees from trading securities, which amounted to ¥83 billion, ¥59 billion and ¥93 billion for the fiscal years ended March 31, 2022, 2023 and 2024, respectively, are within the scope of ASC 606 and accounted for in Trading account gains (losses)—net. Underwriting fees are primarily recognized on the date which all the considerations of the transaction are fixed. For the fiscal years ended March 31, 2022, 2023 and 2024, approximately ¥15 billion, ¥21 billion and ¥25 billion, respectively, of Other noninterest income were within the scope of ASC 606. Credit card interchange fees are within the scope of ASC 606 and accounted for in Other noninterest income. Credit card interchange fees are earned on credit card transactions conducted through payment networks and recognized upon settlement of the credit card payment transactions. Contract balances relating to revenues from contracts with customers subject to ASC 606 Contract assets and receivables from contracts with customers subject to ASC 606 are recognized in Accrued income or accounts receivable of Other assets. As of March 31, 2023 and 2024, the balance of contract assets was not material. Contract liabilities are recognized in unearned income of Other liabilities. As of March 31, 2023 and 2024, the balance of contract liabilities was not material. Remaining performance obligations relating to revenues from contracts with customers subject to ASC 606 Remaining performance obligations are services that the MHFG Group has committed to provide in the future in connection with its contracts with customers. As of March 31, 2023 and 2024, the amount of expected revenues from current obligations to provide services in the future was not material. It excludes revenues from contracts less than one year or contracts that have provisions that allow the Group to recognize revenue at the amount it has the right to invoice.

Trading account gains and losse

Trading account gains and losses	12 Months Ended
	Mar. 31, 2024
Trading Account Gains And Losses [Abstract]
Trading account gains and losses	25. Trading account gains and losses The MHFG Group performs trading activities through market making, sales, and arbitrage. Accordingly, Trading account gains (losses)—net include gains and losses from transactions undertaken for trading purposes, including both market making for customers and proprietary trading, or transactions through which the Group seeks to capture gains arising from short-term changes in market value. Trading account gains (losses)—net also include gains and losses related to changes in the fair value of derivatives and other financial instruments not eligible for hedge accounting under U.S. GAAP that are utilized to offset mainly interest rate risk related to the Group’s various assets and liabilities, as well as gains and losses related to changes in the fair value of foreign currency-denominated debt securities reported as Trading securities. Net trading gains (losses) for the fiscal years ended March 31, 2022, 2023 and 2024 are comprised of the following: 2022 2023 2024 (in millions of yen) Trading account gains (losses)—net: Trading securities (1,230,330 ) (1,003,636 ) (171,498 ) Derivative contracts: Interest rate contracts (130,312 ) (508,743 ) (22,003 ) Foreign exchange contracts (1) 145,979 317,459 387,591 Equity-related contracts 728,226 534,615 240,277 Credit-related contracts (2) (13,272 ) (3,204 ) (2,101 ) Other contracts 7,762 59,599 (42,005 ) Total (491,947 ) (603,910 ) 390,260 Foreign exchange gains (losses)—net (3) 91,611 189,526 (19,390 ) Net trading gains (losses) (400,336 ) (414,384 ) 370,870 Notes: (1) Amounts include gains and losses on currency swaps. (2) Amounts do not include the net gains (losses) of ¥(605) million, ¥(653) million and ¥(952) million on the credit derivatives economically managing the credit risk of loans during the fiscal years ended March 31, 2022, 2023 and 2024, respectively. The net gains (losses) is recorded in Other noninterest income (expenses). (3) Amounts include realized and unrealized gains and losses on both derivative instruments and nonderivative instruments. Amounts on derivative instruments include gains and losses on forward foreign exchange contracts and currency options. Amounts on nonderivative instruments include translation gains and losses related to foreign currency-denominated debt securities reported as Trading securities.

Fair value

Fair value	12 Months Ended
	Mar. 31, 2024
Fair value	26. Fair value Fair value measurements ASC 820 defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. ASC 820 also establishes a fair value hierarchy which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. In addition, ASC 820 precludes (1) the deferral of gains and losses at inception of certain derivative contracts whose fair value was not evidenced by market-observable data, and (2) the use of block discounts when measuring the fair value of instruments traded in an active market, which were previously applied to large holdings of publicly traded financial instruments. Fair value hierarchy ASC 820 specifies a hierarchy of valuation techniques based on whether the inputs to those valuation techniques are observable or unobservable. The standard describes the following three levels of inputs that may be used to measure fair value: Level 1 Quoted prices in active markets for identical assets or liabilities. Level 1 assets and liabilities include debt and equity securities and derivative contracts that are traded in an active exchange market. Level 2 Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 2 assets and liabilities include debt securities with quoted prices that are traded less frequently than exchange-traded instruments. If no quoted market prices are available, the fair values of debt securities and over-the-counter Level 3 Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities include financial instruments whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. Valuation process The MHFG Group has established valuation policies which govern the principles of fair value measurements and the authority and duty of each department. The Group has also established procedure manuals which describe valuation techniques and related inputs for determining the fair values of various financial instruments. The policies require that the measurement of fair values be carried out in accordance with the procedures performed by the risk management departments or the back offices which are independent from the front offices. The policies also require the risk management departments to assess whether the valuation methodologies defined in the procedure manuals are fair and proper and the internal audit departments to periodically review the compliance with the procedures throughout the Group. Although the valuation methodologies and related inputs are consistently applied from period to period, a change in the market environment sometimes leads to a change in the valuation methodologies and the inputs. For instance, a change in market liquidity due to a delisting or a new listing is one of the key drivers of revisions to the valuation methodologies and the inputs. The key drivers also include the availability or the lack of market observable inputs and the development of new valuation methodologies. Price verification performed through the Group’s internal valuation process has an important role in identifying whether the valuation methodologies and the inputs need to be changed. The internal valuation process over the prices broker-dealers provide, primarily for Japanese securitization products, is described in more detail below in Available-for-sale The following is a description of valuation methodologies and inputs used for assets and liabilities measured at fair value on a recurring basis, including the general classification of such instruments pursuant to the fair value hierarchy and the MHFG Group’s valuation techniques used to measure fair values. During the fiscal year ended March 31, 2024, there were no significant changes made to the Group’s valuation techniques and related inputs. Trading securities and trading securities sold, not yet purchased When quoted prices for identical securities are available in an active market, the Group uses the quoted prices to measure the fair values of securities and such securities are classified in Level 1 of the fair value hierarchy. Level 1 securities include highly liquid government bonds and equity securities. When quoted prices for identical securities are available, but not actively traded, such securities are classified in Level 2 of the fair value hierarchy. When no quoted market prices are available, the Group estimates fair values by using pricing models with inputs that are observable in the market and such securities are classified in Level 2 of the fair value hierarchy. Level 2 securities include Japanese local government bonds, corporate bonds, and commercial paper. When less liquid market conditions exist for securities, the quoted prices are stale or the prices from independent sources vary significantly, such securities are generally classified in Level 3 of the fair value hierarchy. The fair values of securitization products such as RMBS, CMBS, ABS, and CLO are determined primarily by using a discounted cash flow model. The key inputs used for the model include default rates, recovery rates, prepayment rates, and discount rates. Though most securitization products are classified in Level 2, if the significant inputs are unobservable or cannot be corroborated by observable market data, these financial instruments are classified in Level 3. Hedge funds the Group invests in are primarily multi-strategy funds that employ a fundamental bottom-up start-up ten-year Derivative financial instruments Exchange-traded derivatives are valued using quoted market prices and consequently are classified in Level 1 of the fair value hierarchy. However, the majority of derivatives entered into by the Group are executed over-the-counter over-the-counter over-the-counter of the instrument. The Group calculates these funding valuation adjustments incorporating the expected future funding requirements arising from the Group’s positions and the estimated market funding cost which considers the Group’s credit risk. The Group measures these valuation adjustments based on net exposure of a group of financial assets and financial liabilities to credit risk. Available-for-sale The fair values of available-for-sale non-binding Equity securities Equity securities mainly consist of marketable equity securities. The fair values of the marketable equity securities are based upon quoted market prices for identical equity securities trading as securities in an active market. Equity securities also include investments in certain investment funds measured using the NAV per share practical expedient including private equity funds and real estate funds. These securities are determined primarily using the same procedures described under Trading securities and trading securities sold, not yet purchased Other investments Other investments consist of investments held by consolidated investment companies. These companies typically hold investments in marketable and non-marketable non-marketable Non-marketable Other assets Other assets measured at fair value consist of securities received as collateral that may be sold or repledged under securities lending transactions. The securities received as collateral under lending transactions mainly consist of certain foreign government bonds and securitization products which are valued using the valuation techniques described under Trading securities and trading securities sold, not yet purchased Long-term debt and Other short-term borrowings Fair value accounting is elected for certain debt instruments with embedded derivatives. The fair values are determined using a discounted cash flow model that considers the embedded derivatives and the terms and payment structures of the notes. The fair values of the derivatives embedded in such notes are primarily derived by using the same procedures described in Derivative financial instruments Other liabilities Other liabilities measured at fair value consist of obligation to return securities received as collateral under securities lending transactions, which are measured at the fair value of the securities received as collateral. The securities consist primarily of certain foreign government bonds and securitization products, whose fair values are measured using the valuation techniques described under Trading securities and trading securities sold, not yet purchased Items measured at fair value on a recurring basis Assets and liabilities measured at fair value on a recurring basis at March 31, 2023 and 2024, including those for which the MHFG Group has elected the fair value option, are summarized below: 2023 Level 1 Level 2 Level 3 Assets/ Liabilities measured at fair value (in billions of yen) Assets: Trading securities (1) Japanese government bonds 1,187 7 —  1,194 Japanese local government bonds —  138 —  138 U.S. Treasury bonds and federal agency securities 1,917 1,377 —  3,294 Other foreign government bonds 658 786 —  1,444 Agency mortgage-backed securities —  5,309 —  5,309 Certificates of deposit and commercial paper —  516 —  516 Corporate bonds and other (2) —  2,406 47 2,453 Equity securities 1,859 370 21 2,250 Trading securities measured at net asset value (3) 111 Derivative financial instruments: Interest rate contracts 218 8,103 53 8,374 Foreign exchange contracts —  4,200 22 4,222 Equity-related contracts 39 73 33 145 Credit-related contracts —  143 1 144 Other contracts 15 12 20 47 Available-for-sale Japanese government bonds 15,771 678 —  16,449 Japanese local government bonds —  555 —  555 U.S. Treasury bonds and federal agency securities 376 —  —  376 Other foreign government bonds 322 986 —  1,308 Agency mortgage-backed securities —  522 —  522 Residential mortgage-backed securities —  34 13 47 Commercial mortgage-backed securities —  862 —  862 Japanese corporate bonds and other debt securities —  2,008 101 2,109 Foreign corporate bonds and other debt securities —  916 90 1,006 Equity securities: Equity securities with readily determinable fair values 3,052 161 —  3,213 Equity securities measured at net asset value (3) 271 Other investments —  —  63 63 Total assets measured at fair value on a recurring basis 25,414 30,162 464 56,422 Liabilities: Trading securities sold, not yet purchased 2,954 3,513 —  6,467 Derivative financial instruments: Interest rate contracts 244 8,271 2 8,517 Foreign exchange contracts —  4,005 8 4,013 Equity-related contracts 46 91 60 197 Credit-related contracts —  124 2 126 Other contracts 10 15 18 43 Long-term debt (4) —  1,844 836 2,680 Total liabilities measured at fair value on a recurring basis 3,254 17,863 926 22,043 2024 Level 1 Level 2 Level 3 Assets/ Liabilities measured at fair value (in billions of yen) Assets: Trading securities (1) Japanese government bonds 1,623 5   —  1,628 Japanese local government bonds —  135 —  135 U.S. Treasury bonds and federal agency securities 3,534 1,468 —  5,002 Other foreign government bonds 676 897 —  1,572 Agency mortgage-backed securities —  6,717 —  6,717 Certificates of deposit and commercial paper —  351 —  351 Corporate bonds and other (2) —  3,208 189 3,397 Equity securities 2,743 209 21 2,973 Trading securities measured at net asset value (3) 109 Derivative financial instruments: Interest rate contracts 14 8,640 14 8,668 Foreign exchange contracts —  5,610 2 5,612 Equity-related contracts 79 255 6 340 Credit-related contracts —  213 1 214 Other contracts 21 9 10 40 Available-for-sale Japanese government bonds 10,562 412 —  10,974 Japanese local government bonds —  584 —  584 U.S. Treasury bonds and federal agency securities 147 —  —  147 Other foreign government bonds 922 1,122 —  2,045 Agency mortgage-backed securities —  477 —  477 Residential mortgage-backed securities —  24 8 31 Commercial mortgage-backed securities —  801 4 804 Japanese corporate bonds and other debt securities —  1,666 167 1,833 Foreign corporate bonds and other debt securities —  795 23 818 Equity securities: Equity securities with readily determinable fair values 4,165 296 —  4,461 Equity securities measured at net asset value (3) 334 Other investments 1 —  80 80 Other assets 3 68 —  71 Total assets measured at fair value on a recurring basis 24,489 33,961 525 59,419 Liabilities: Trading securities sold, not yet purchased 3,445 2,258 —  5,703 Derivative financial instruments: Interest rate contracts 14 8,697 1 8,712 Foreign exchange contracts —  5,571 11 5,582 Equity-related contracts 105 213 76 394 Credit-related contracts —  174 6 180 Other contracts 13 26 10 50 Other short-term borrowings (4) —  153 —  153 Long-term debt (4) —  2,450 427 2,876 Other liabilities 3 68 —  71 Total liabilities measured at fair value on a recurring basis 3,580 19,610 531 23,721 Notes: (1) Trading securities include foreign currency denominated securities for which the MHFG Group elected the fair value option. (2) The amount includes CLO and convertible bonds, which are classified in Level 3. (3) In accordance with ASC 820, certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented for these classes of assets are intended to permit the reconciliation of the fair value hierarchy to the amounts presented in the statements of financial position. The amounts of unfunded commitments related to these investments at March 31, 2023 and 2024 were ¥52 billion and ¥41 billion, respectively. (4) Amounts represent items for which the Group elected the fair value option or for which it applied the practicability exception. Items measured at fair value on a recurring basis using significant unobservable inputs (Level 3) The following table presents a reconciliation for all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the fiscal years ended March 31, 2023 and 2024: 2023 April 1, 2022 Gains (losses) in Earnings Gains (losses) in OCI Transfers into Level 3 Transfers out of Level 3 Purchases Sales Issuances Settle- ments March 31, 2023 Change in unrealized gains (losses) still (6) (in billions of yen) Assets: Trading securities: Residential mortgage- backed securities 8 (1 ) (2) —  —  —  —  (6 ) —  (1 ) —  —  Corporate bonds and other 71 4 (2) —  13 (15 ) 104 (46 ) —  (84 ) 47 —  Equity securities 28 —  (2) —  —  —  2 (6 ) —  (3 ) 21 (1 ) Derivative financial instruments, net (1) Interest rate contracts. 22 31 (2) —  —  —  —  —  —  (2 ) 51 (22 ) Foreign exchange contracts 32 (5 ) (2) —  —  —  —  —  —  (13 ) 14 (6 ) Equity-related contracts (14 ) (26 ) (2) —  —  —  —  —  —  13 (27 ) (107 ) Credit-related contracts 1 (1 ) (2) —  —  —  —  —  —  (1 ) (1 ) (5 ) Other contracts —  2 (2) —  —  —  —  —  —  —  2 2 Available-for-sale Residential mortgage- backed securities 18 —  (3) —  (4) —  —  —  —  —  (5 ) 13 —  Commercial mortgage-backed securities —  —  (3) —  (4) —  —  —  —  —  —  —  —  Japanese corporate bonds and other debt securities 315 —  (3) 3 (4) —  —  25 —  —  (242 ) 101 8 Foreign corporate bonds and other debt securities 117 —  (3) 1 (4) —  (54 ) 63 —  —  (37 ) 90 —  Other investments 56 3 (3) —  —  (1 ) 36 —  —  (31 ) 63 1 Liabilities: Trading securities sold, not yet purchased —  —  (2) —  —  —  (1 ) 1 —  —  —  —  Long-term debt 794 29 (5) 10 (4) 1 (2 ) —  —  323 (241 ) 836 60 2024 April 1, 2023 Gains (losses) in Earnings Gains (losses) in OCI Transfers into Level 3 Transfers out of Level 3 Purchases Sales Issuances Settle- ments March 31, 2024 Change in unrealized gains (losses) still held (6) (in billions of yen) Assets: Trading securities: Residential mortgage- backed securities —  — (2)   —   —  —  —  —  —  —  —  —  Corporate bonds and other 47 12 (2) —  15 (7 ) 214 (59 ) —  (34 ) 189 9 Equity securities 21 — (2) —  —  —  3 (1 ) —  (1 ) 21 —  Derivative financial instruments, net (1) Interest rate contracts. 51 (44 ) (2) —  —  (32 ) —  —  —  38 13 8 Foreign exchange contracts 14 (8 ) (2) —  —  —  —  —  —  (15 ) (9 ) (10 ) Equity-related contracts (27 ) (62 ) (2) —  —  (1 ) —  —  —  20 (70 ) (37 ) Credit-related contracts (1 ) (6 ) (2) —  —  —  —  —  —  2 (5 ) (3 ) Other contracts 2 (1 ) (2) —  —  —  —  —  —  (1 ) —  (1 ) Available-for-sale Residential mortgage- backed securities 13 — (3) —  (4) —  —  —  (2 ) —  (3 ) 8 —  Commercial mortgage-backed securities —  — (3) —  (4) —  —  4 —  —  —  4 —  Japanese corporate bonds and other debt securities 101 — (3) 9 (4) —  —  106 —  —  (49 ) 167 12 Foreign corporate bonds and other debt securities 90 8 (3) —  (4) —  (2 ) 10 —  —  (82 ) 23 (1 ) Other investments 63 1 (3) —  —  —  47 —  —  (31 ) 80 —  Liabilities: Trading securities sold, not yet purchased —  — (2) —  —  —  —  —  —  —  —  —  Long-term debt 836 (57 ) (5) (14 ) (4) 1 (285 ) —  —  276 (472 ) 427 (11 ) Notes: (1) Total Level 3 derivative exposures have been netted on the table for presentation purposes only. (2) Gains (losses) in Earnings are reported in Trading account gains (losses)—net, Foreign exchange gains (losses)—net or Other noninterest income (expenses). (3) Gains (losses) in Earnings are reported in Investment gains (losses)—net. (4) Gains (losses) in OCI are reported in Other comprehensive income (loss). (5) Gains (losses) in Earnings are reported in Other noninterest income (expenses). (6) Amounts represent total gains or losses recognized in earnings and other comprehensive income (loss) during the period. These gains or losses were attributable to the change in fair value relating to assets and liabilities classified as Level 3 that were still held at March 31, 2023 and 2024. The amounts of unrealized gains (losses) in other comprehensive income (loss) are related to Available-for-sale Transfers between levels During the fiscal year ended March 31, 2023, the transfers into Level 3 included ¥13 billion of Trading securities and ¥1 billion of Long-term debt. Transfers into Level 3 for Trading securities were primarily due to decreased price transparency for certain foreign bonds. Transfers into Level 3 for Long-term debt were primarily due to the decrease in the observability of the default rate when valuing certain structured notes. During the fiscal year ended March 31, 2023, the transfers out of Level 3 included ¥15 billion of Trading securities, ¥54 billion of Available-for-sale Other investments. Transfers out of Level 3 for Trading securities were primarily due to increased price transparency for certain foreign bonds. Transfers out of Level 3 for Available-for-sale During the fiscal year ended March 31, 2024, the transfers into Level 3 included ¥15 billion of Trading securities and ¥1 billion of Long-term debt. Transfers into Level 3 for Trading securities were primarily due to decreased price transparency for certain foreign bonds. Transfers into Level 3 for Long-term debt were primarily due to the decrease Available-for-sale billion of Long-term debt. Transfers out of Level 3 for Trading securities were primarily due to increased price transparency for certain foreign bonds. Transfers out of Level 3 for net Derivative assets were primarily due to the decrease in significance of unobservable inputs as a result of quantitative sensitivity analysis for certain interest rate derivatives. Transfers out of Level 3 for Available-for-sale Quantitative information about Level 3 fair value measurements The following table presents information about significant unobservable inputs related to the MHFG Group’s material classes of Level 3 assets and liabilities at March 31, 2023 and 2024: 2023 Products/Instruments Fair value Principal valuation technique Unobservable inputs Range of input values Average (4) (in billions of yen, except for percentages and basis points) Trading securities and Available-for-sale Residential mortgage-backed securities 13 Discounted cash flow Prepayment rate 0.2%–17.6% 4.4% Price-based Default rate 0.0%–2.2% 0.2% Recovery rate 100.0%–100.0% 100.0% Discount margin 30.0bps–167.1bps 47.0bps Corporate bonds and other debt securities 238 Discounted cash flow Prepayment rate (1) 21.7%–21.7% 21.7% Price-based Default rate (1) 0.2%–0.2% 0.2% Recovery rate (1) 40.5%–40.5% 40.5% Discount margin (1) 98.8bps–209.9bps 116.2bps Discount margin (2) 3.5bps–171.2bps 20.1bps Derivative financial instruments, net: Interest rate 51 Internal valuation model (3) IR – IR correlation 23.2%–100.00% 75.0% Foreign exchange contracts 14 Internal valuation model (3) FX – IR correlation 5.5%–58.2% 39.9% FX – FX correlation 39.0%–64.7% 51.9% Equity-related contracts (27 ) Internal valuation model (3) Equity – IR correlation 25.0%–25.0% 25.0% Equity – FX correlation 0.0%–60.0% 33.7% Equity correlation 73.9%–100.0% 96.7% Equity volatility 10.3%–95.4% 44.1% Credit-related contracts (1 ) Internal valuation model (3) Default rate 0.1%–12.2% 2.1% Other contracts 2 Internal valuation model (3) Commodity volatility 20.0%–54.5% 39.8% Long-term debt 836 Internal valuation model (3) IR – IR correlation 23.2%–100.0% 75.0% FX – IR correlation 5.5%–58.2% 39.9% FX – FX correlation 39.0%–64.7% 51.9% Equity – IR correlation 25.0%–25.0% 25.0% Equity – -16.3%–93.3% 0.0% Equity correlation 3.2%–100.0% 90.8% Equity volatility 5.9%–180.8% 34.1% Default rate 0.1%–13.1% 2.3% Credit correlation 47.6%–100.0% 68.3% 2024 Products/Instruments Fair value Principal valuation technique Unobservable inputs Range of input values Average (4) (in billions of yen, except for percentages and basis points) Trading securities and Available-for-sale Residential mortgage-backed securities 8 Discounted cash flow Prepayment rate 0.4%–6.2% 3.8% Price-based Recovery rate 100.0%–100.0% 100.0% Discount margin 30.0bps–65.0bps 40.1bps Commercial mortgage-backed securities 4 Discounted cash flow Price-based Discount margin 158.7bps–291.4bps 234.2bps Corporate bonds and other debt securities 380 Discounted cash flow Prepayment rate (1) 3.2%–3.2% 3.2% Price-based Default rate (1) 0.4%–0.4% 0.4% Recovery rate (1) 36.9%–36.9% 36.9% Discount margin (1) 56.9bps–56.9bps 56.9bps Discount margin (2) 38.2bps–187.7bps 63.6bps Derivative financial instruments, net: Interest rate contracts 13 Internal valuation model (3) IR – IR correlation 23.2%–100.0% 71.4% Foreign exchange contracts (9 ) Internal valuation model (3) FX – IR correlation 13.8%–72.5% 29.9% FX – FX correlation 39.0%–64.7% 51.9% Equity-related contracts (70 ) Internal valuation model (3) Equity – IR correlation 25.0%–25.0% 25.0% Equity – FX correlation 15.0%–60.0% 60.0% Equity volatility 9.8%–121.8% 42.1% Credit-related contracts (5 ) Internal valuation model (3) Default rate 0.0%–6.4% 1.4% Other contracts — Internal valuation model (3) Commodity volatility 0.0%–27.7% 23.7% Long-term debt 427 Internal valuation model (3) IR – IR correlation 23.2%–100.0% 71.4% FX – IR correlation 5.5%–72.5% 29.9% FX – FX correlation 39.0%–64.7% 51.9% Equity – IR correlation 25.0%–25.0% 25.0% Equity – FX correlation -17.8%–93.3% 0.0% Equity correlation 32.2%–100.0% 87.3% Equity volatility 9.8%–70.7% 25.8% Default rate 0.0%–9.5% 1.4% Notes: (1) These inputs are mainly used for determining the fair values of securitization products such as CDO, CLO and ABS, other than RMBS and CMBS. (2) This input is mainly used for determining the fair values of Japanese corporate bonds and foreign corporate bonds. (3) Internal valuation model includes discounted cash flow models and the Black-Scholes option pricing model. (4) Averages are calculated by weighting each input by the relative fair value of the respective financial instruments except for derivative related inputs where medians are used. (5) The range of inputs for equity securities is not disclosed, as there is a dispersion of values given the number of positions. IR = Interest rate FX = Foreign exchange Uncertainty of fair value measurements relating to unobservable inputs and interrelationships among unobservable inputs The following is a description of the uncertainty of the fair value measurements from the use of significant unobservable inputs and a description of interrelationships of the significant unobservable inputs used to measure the fair values of Level 3 assets and liabilities. (1) Prepayment rate The prepayment rate is the estimated rate at which voluntary unscheduled repayments of the principal of the underlying assets are expected to occur. The movement of the prepayment rate is generally negatively correlated with borrower delinquency. A change in prepayment rate would impact the valuation of the fair values of financial instruments either positively or negatively, depending on the structure of financial instruments. (2) Default rate The default rate is an estimate of the likelihood of not collecting contractual payments. An increase in the default rate would generally be accompanied by a decrease in the recovery rate and an increase in the discount margin. It would also generally impact the valuation of the fair values of financial instruments negatively. (3) Recovery rate The recovery rate is an estimate of the percentage of contractual payments that would be collected in the event of a default. An increase in recovery rate would generally be accompanied by a decrease in the default rate. It would also generally impact the valuation of the fair values of financial instruments positively. (4) Discount margin The discount margin is the portion of the interest rate over a benchmark market interest rate such as Tokyo Interbank Offered Rate (“TIBOR”) or swap rates. It primarily consists of a risk premium component which is the amount of compensation that market participants require due to the uncertainty inherent in the financial instruments’ cash flows resulting from credit risk. An increase in discount margin would generally impact the valuation of the fair values of financial instruments negatively. (5) Correlation Correlation is the likelihood of the movement of one input relative to another based on an established relationship. The change in correlation would impact the valuation of derivatives either positively or negatively, depending on the nature of the underlying assets. (6) Volatility Volatility is a measure of the expected change in variables over a fixed period of time. Some financial instruments benefit from an increase in volatility and others benefit from a decrease in volatility. Generally, for a long position in an option, an increase in volatility would result in an increase in the fair values of financial instruments. Items measured at fair value on a nonrecurring basis Certain assets and liabilities are measured at fair value on a nonrecurring basis. These assets and liabilities primarily include items that are measured at the lower of cost or fair value, and items that were initially measured at cost and have been written down to fair value as a result of impairment. The following table shows the fair value hierarchy for these items as of March 31, 2023 and 2024: 2023 Total Level 1 Level 2 Level 3 Aggregate cost (in billions of yen) Assets: Loans 97 —  —  97 165 Loans held-for-sale 216 —  16 200 282 Equity securities (without readily determinable fair values) 4 —  4 —  5 Other investments 94 93 —  1 122 Premises and equipment—net 1 —  —  1 2 Total assets measured at fair value on a nonrecurring basis 412 93 20 299 576 2024 Total Level 1 Level 2 Level 3 Aggregate cost (in billions of yen) Assets: Loans 101 —  —  101 187 Loans held-for-sale 95 —  2 94 150 Equity securities (without readily determinable fair values) 34 —  2 31 39 Other investments 153 —  —  153 199 Premises and equipment—net —  —  —  —  6 Intangible assets —  —  —  —  1 Total assets measured at fair value on a nonrecurring basis 383 —  4 379 581 Note: The fair values may not be current as of the dates indicated, but rather as of the date the fair value change occurred. Accordingly, the carrying values may not equal current fair value. Loans in the table above are classified as nonaccrual and are measured based upon the observable market price of the loan, which are classified as Level 2, or the fair value of the underlying collateral, which are classified as Level 3. Loans held-for-sale held-for-sale Equity securities (without readily determinable fair values) in the table above consist of non-marketable non-marketable non-marketable equity securities are determined primarily by using a liquidation value technique. As significant management judgment or estimation is required in the determination of the fair values of non-marketable non-marketable Other investments in the table above include certain equity method investments which have been impaired and written down to fair value. The fair values of the impaired marketable equity method investments are determined by their quoted market prices. As the securities are traded on an active exchange market, they are classified as Level 1. The fair values of the impaired non-marketable non-marketable Premises and equipment—net and Intangible assets in the table above have been impaired and written down to fair value. There were no intangible assets measured at fair value on a nonrecurring basis as of March 31, 2023. Fair value option The MHFG Group elected the fair value option for certain eligible financial instruments described below. Foreign currency denominated debt securities The MHFG Group elected the fair value option for foreign currency denominated debt securities to mitigate the volatility in earnings due to the difference in the recognition of foreign exchange risk between foreign currency denominated debt securities and financial liabilities. Following the election of the fair value option, these debt securities are reported as trading securities in Trading account assets. Certain hybrid financial instruments The MHFG Group issues structured notes as part of its client-driven activities. Structured notes are debt instruments that contain embedded derivatives. The Group elected the fair value option for certain structured notes to mitigate accounting mismatches and to achieve operational simplifications. Fair value option has only been elected for part of the portfolio as the Group would not achieve operational simplifications. In addition, the Group measures certain notes that contain embedded derivatives at fair value under the practicability exception. These notes continue to be reported in Other short-term borrowings and Long-term debt. The interest on these notes continues to be reported in Interest expense on other short-term borrowings and long-term debt based on the contractual rates. Only an immaterial amount included in Other short-term borrowings and Long-term debt in the statement of financial position is not eligible for fair value option. The differences between the aggregate fair value of these notes and the aggregate unpaid principal balance of such instruments were ¥161 billion and ¥62 billion at March 31, 2023 and 2024, respectively. The net unrealized gains (losses) resulting from changes in fair values of these notes recorded in Other noninterest income (expenses) were of ¥38 billion, ¥54 billion and ¥(48) billion for the fiscal years ended March 31, 2022, 2023 and 2024, respectively. Changes in fair value resulting from changes in instrument-specific credit risk were estimated by incorporating the Company’s current credit spreads observable in the bond market. Fair value of financial instruments ASC 825, “Financial Instruments” (“ASC 825”), requires the disclosure of the estimated fair value of financial instruments. The fair value of financial instruments is the amount that would be exchanged between willing parties, other than in a forced sale or liquidation. Quoted market prices, if available, are best utilized as estimates of the fair values of financial instruments. However, since no quoted market prices are available for certain financial instruments, fair values for such financial instruments have been estimated based on management’s assumptions, discounted cash flow models or other valuation techniques. Such est

Offsetting of financial assets

Offsetting of financial assets and financial liabilities	12 Months Ended
	Mar. 31, 2024
Offsetting of financial assets and financial liabilities	27. Offsetting of financial assets and financial liabilities Derivatives The MHFG Group enters into master netting arrangements such as International Swaps and Derivatives Association, Inc. (“ISDA”) or similar agreements with counterparties to manage mainly credit risks associated with counterparty default. If the predetermined events including counterparty default occur, these enforceable master netting arrangements or similar agreements give the Group the right to offset derivative receivables and derivative payables and related financial collateral such as cash and securities with the same counterparty. Repurchase and resale agreements and securities lending and borrowing transactions Repurchase and resale agreements and securities lending and borrowing transactions are generally covered by industry standard master repurchase agreements and industry standard master securities lending agreements with netting terms to manage mainly credit risks associated with counterparty default. In the event of default by the counterparty, these agreements with netting terms provide the Group with the right to offset receivables and payables related to such transactions with the same counterparty, and to liquidate the collateral held. The following table provides information about the offsetting of financial assets and financial liabilities at March 31, 2023 and 2024. The table includes derivatives, repurchase and resale agreements, and securities lending and borrowing transactions that are subject to enforceable master netting arrangements or similar agreements irrespective of whether or not they are offset on the Group’s consolidated balance sheets. Gross amounts recognized Gross amounts offset on the balance sheet Net amounts presented on the (2) Amounts not offset on the balance sheet (3) Net amounts Financial instruments (4) Cash collateral (in billions of yen) 2023 Assets (1) Derivatives 12,932 —  12,932 (5) (10,476 ) (821 ) 1,635 Receivables under resale agreements 11,695 —  11,695 (6) (10,565 ) —  1,130 Receivables under securities borrowing transactions 1,892 —  1,892 (7) (1,866 ) —  26 Total 26,519 —  26,519 (22,907 ) (821 ) 2,791 Liabilities (1) Derivatives 12,896 —  12,896 (5) (10,141 ) (843 ) 1,912 Payables under repurchase agreements 25,737 —  25,737 (6) (25,113 ) —  624 Payables under securities lending transactions 886 —  886 (7) (755 ) —  131 Total 39,519 —  39,519 (36,009 ) (843 ) 2,667 2024 Assets (1) Derivatives 14,874 —  14,874 (5) (11,525 ) (1,065 ) 2,284 Receivables under resale agreements 20,535 —  20,535 (6) (19,431 ) —  1,103 Receivables under securities borrowing transactions 2,352 —  2,352 (7) (2,261 ) —  91 Total 37,761 —  37,761 (33,217 ) (1,065 ) 3,478 Liabilities (1) Derivatives 14,918 —  14,918 (5) (10,941 ) (1,137 ) 2,840 Payables under repurchase agreements 38,105 —  38,105 (6) (36,842 ) —  1,262 Payables under securities lending transactions 1,350 —  1,350 (7) (1,298 ) —  52 Other liabilities (8) 71 —  71 (60 ) —  11 Total 54,444 —  54,444 (49,142 ) (1,137 ) 4,166 Notes: (1) Amounts relating to master netting arrangements or similar agreements where the MHFG Group does not have the legal right of set-off over-the-counter OTC-cleared (2) Derivative assets and liabilities are recorded in Trading account assets and Trading account liabilities, respectively. (3) Amounts do not exceed the net amounts presented on the balance sheet and do not include the effect of overcollateralization, where it exists. (4) For derivatives, amounts include derivative assets or liabilities and securities collateral that are eligible for offsetting under enforceable master netting arrangements or similar agreements. (5) The amounts of derivative assets and liabilities subject to enforceable master netting arrangements or similar agreements were ¥12,574 billion and ¥12,432 billion, respectively, at March 31, 2023, and ¥13,930 billion and ¥13,933 billion, respectively, at March 31, 2024. (6) The amounts of Receivables under resale agreements and Payables under repurchase agreements subject to enforceable industry standard master repurchase agreements with netting terms were ¥10,587 billion and ¥25,147 billion, respectively, at March 31, 2023, and ¥19,470 billion and ¥37,042 billion, respectively, at March 31, 2024. (7) The amounts of Receivables under securities borrowing transactions and Payables under securities lending transactions subject to enforceable industry standard master lending agreements with netting terms were ¥1,892 billion and ¥758 billion, respectively, at March 31, 2023, and ¥2,352 billion and ¥1,303 billion, respectively, at March 31, 2024. (8) Amounts relate to transactions where the Group acts as lender in a securities lending agreement and receives securities that can be sold or pledged as collateral. In these transactions, the Group recognizes the securities received at fair value within Other assets and the obligation to return those securities as a liability within Other liabilities.

Repurchase agreements and secur

Repurchase agreements and securities lending transactions accounted for as secured borrowings	12 Months Ended
	Mar. 31, 2024
Repurchase agreements and securities lending transactions accounted for as secured borrowings	28. Repurchase agreements and securities lending transactions accounted for as secured borrowings The following table shows the gross amounts of liabilities associated with repurchase agreements and securities lending transactions, by remaining contractual maturity at March 31, 2023 and 2024: Overnight and continuous Up to 30 days 31-90 days Greater than 90 days Total (in billions of yen) 2023 Repurchase agreements 2,285 16,508 5,471 1,473 25,737 Securities lending transactions 685 73 —  128 886 Total 2,970 16,581 5,471 1,601 26,623 2024 Repurchase agreements 18,661 11,040 5,415 2,989 38,105 Securities lending transactions 1,288 19 —  44 1,350 Total 19,949 11,058 5,415 3,033 39,455 The following table shows the gross amounts of liabilities associated with repurchase agreements and securities lending transactions, by class of underlying collateral at March 31, 2023 and 2024: Repurchase agreements Securities lending transactions (in billions of yen) 2023 Japanese government bonds and Japanese local government bonds 6,114 102 Foreign government bonds and foreign agency mortgage-backed securities 17,475 73 Commercial paper and corporate bonds 430 —  Equity securities 1,491 711 Other 227 —  Total 25,737 886 2024 Japanese government bonds and Japanese local government bonds 6,167 102 Foreign government bonds and foreign agency mortgage-backed securities 28,757 19 Commercial paper and corporate bonds 913 —  Equity securities 1,609 1,229 Other 658 —  Total (Note) 38,105 1,350 Note: The above table does not include securities-for-securities lending transactions of ¥71 billion at March 31, 2024, where the MHFG Group acts as lender and receives securities that can be sold or pledged as collateral. In these transactions, the Group recognizes the securities received at fair value within Other assets and the obligation to return those securities as a liability within Other liabilities. The MHFG Group is required to post securities as collateral with a fair value equal to or in excess of the principal amount of the cash borrowed under repurchase agreements. For securities lending transactions, the Group receives collateral in the form of cash. These contracts involve risks, including (1) the counterparty may fail to return the securities at maturity and (2) the fair value of the securities posted may decline below the amount of the Group’s obligation and therefore the counterparty may require additional amounts. The Group attempts to mitigate these risks by entering into transactions mainly with central counterparty clearing houses which revalue assets and perform margin maintenance activities on a regular basis, diversifying the maturities and counterparties, and using mainly highly liquid securities.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Mar. 31, 2024
Text Block [Abstract]
Related Party Transactions	29. Related party transactions The banking subsidiaries of MHFG make loans to the MHFG Group’s directors, executive officers, and other related parties. At March 31, 2023 and 2024, the aggregate loans to the Group’s equity method investees amounted to ¥732 billion and ¥914 billion, respectively, and outstanding loans to MHFG Group’s directors, executive officers, and other related parties were not considered significant. There were no loans to related parties that were considered nonaccrual. During the fiscal years ended March 31, 2023 and 2024, certain subsidiaries of MHFG partially withdrew assets from employee retirement benefit trusts, which were established for the payment of employees’ severance pay and retirement pensions. See Note 20 “Pension and other employee benefit plans” for further details. In addition, the other transactions with the related parties excluding loan transactions and partial withdrawal of assets from employee retirement benefit trusts, are considered immaterial. Summarized Financial Information of the MHFG Group’s Equity Method Investees Summarized financial information of the MHFG Group’s equity method investees as of March 31, 2023 and 2024, and for each of the three years ended March 31, 2024, is as follows: 2023 2024 (in billions of yen) Loans 6,037 6,924 Total assets 29,367 28,447 Deposits 6,216 2,684 Total liabilities 26,506 24,829 Total equity 2,861 3,618 Noncontrolling interests 16 29 2022 2023 2024 (in billions of yen) Total interest and dividend income    625    750    958 Total interest expense 182 239 384 Provision (credit) for credit losses 104 96 83 Net interest income after provision (credit) for credit losses 339 415 490 Income before income tax expense 332 261 394 Net income 246 194 298

Business segment information

Business segment information	12 Months Ended
	Mar. 31, 2024
Business segment information	30. Business segment information The MHFG Group consists of the following five in-house The services that each in-house RBC This company provides financial services for individual customers, small and medium-sized CIBC This company provides financial services for large corporations, financial institutions and public corporations in Japan. GCIBC This company provides financial services for Japanese overseas affiliated corporate customers and non-Japanese GMC This company invests in financial products with market risk, such as interest rate risk, equity risk, and credit risk. AMC This company develops financial products and provides financial services that match the asset management needs of its wide range of customers from individuals to institutional investors. The reportable segment information, set forth below, is derived from the internal management reporting systems used by management to measure the performance of the Group’s operating segments. Management measures the performance of each of the operating segments in accordance with internal managerial accounting rules and practices. In addition, the format and information are presented primarily on the basis of Japanese GAAP. Therefore, they are not consistent with the consolidated financial statements prepared in accordance with U.S. GAAP. A reconciliation is provided for the total amount of all business segments’ “Net business profits (losses) + Net gains (losses) related to ETFs and others” with income before income tax expense under U.S. GAAP, and the total amount of all business segments’ “Fixed assets” with the total amount of Premises and equipment-net, right-of-use As background, effective as of April 1, 2023, MHFG partially restructured its in-house in-house MHFG (Consolidated) 2022 (1) RBC CIBC GCIBC GMC AMC Others (6) Total (in billions of yen) Gross profits + Net gains (losses) related to ETFs and others (2)   717.5   499.8   553.0   383.8    59.4    40.5 2,254.3 General and administrative expenses (3) 617.8 205.9 286.4 230.7 33.4 40.5 1,414.9 Equity in earnings (losses) of equity method investees—net 5.8 3.7 14.3 —  1.5 —  25.4 Amortization of goodwill and others 2.1 —  0.3 0.8 7.2 0.9 11.6 Net business profits (losses) (4) 103.4 297.4 280.5 152.3 20.3 (1.0 ) 853.1 Fixed assets (5) 486.9 161.7 165.8 87.9 —  794.7 1,697.2 MHFG (Consolidated) 2023 (1) RBC CIBC GCIBC GMC AMC Others (6) Total (in billions of yen) Gross profits + Net gains (losses) related to ETFs and others (2)   706.5   508.7   627.1   314.2    54.7    68.7 2,280.2 General and administrative expenses (3) 605.7 202.0 309.2 253.4 35.0 67.9 1,473.5 Equity in earnings (losses) of equity method investees—net (18.3 ) 6.3 20.3 —  —  3.5 11.8 Amortization of goodwill and others 2.0 —  0.7 0.7 6.8 0.9 11.4 Net business profits (losses) (4) 80.3 312.9 337.5 59.9 12.8 3.5 807.1 Fixed assets (5) 483.3 152.8 177.7 87.3 —  777.3 1,678.5 MHFG (Consolidated) 2024 (1) RBC CIBC GCIBC GMC AMC Others (6) Total (in billions of yen) Gross profits + Net gains (losses) related to ETFs and others (2) 749.2 556.3 670.2 432.4 57.2 206.8 2,672.2 General and administrative expenses (3) 651.1 217.7 352.4 307.4 36.1 117.0 1,681.9 Equity in earnings (losses) of equity method investees—net 6.9 7.6 22.0 —  (11.8 ) 1.4 26.2 Amortization of goodwill and others —  —  2.3 —  6.4 1.8 10.7 Net business profits (losses) (4) 105.0 346.1 337.4 125.0 2.7 89.4 1,005.8 Fixed assets (5) 533.8 157.1 197.9 90.3 —  885.4 1,864.6 Notes: (1) Income and expenses of foreign branches of MHBK and foreign subsidiaries with functional currencies other than Japanese Yen have been translated for purposes of segment reporting using the budgeted foreign currency rates. Prior period comparative amounts for such foreign currency income and expenses have been translated using current period budgeted foreign currency rates. (2) “Gross profits + Net gains (losses) related to ETFs and others” is reported instead of sales reported by general corporations. Gross profits is defined as the sum of net interest income, fiduciary income, net fee and commission income, net trading income and net other operating income. Net gains (losses) related to ETFs and others consist of net gains (losses) on ETFs held by MHBK and MHTB on their non-consolidated (3) “General and administrative expenses” excludes non-allocated (4) Net business profits (losses) is used in Japan as a measure of the profitability of core banking operations, and is defined as gross profits (as defined above) less general and administrative expenses (excluding non-allocated (5) “Fixed assets” is presented based on Japanese GAAP and corresponds to the total amount of the following U.S. GAAP accounts: Premises and equipment-net; right-of-use (6) “Others” includes the following items: • profits and expenses pertaining to consolidated subsidiaries that are not subject to allocation; • consolidating adjustments, including elimination of internal transaction between each segment; • equity in earnings (losses) of equity method investees—net that are not subject to allocation; and • profits and losses pertaining to derivative transactions that reflect the counterparty risk of the individual parties and other factors in determining fair market value. Reconciliation As explained above, the measurement bases of the internal management reporting systems and the income and expenses items included are different from the accompanying consolidated statements of income. Therefore, it is impracticable to present reconciliations of all the business segment’s information, other than net business profits (losses), to the corresponding items in the accompanying consolidated statements of income. A reconciliation of “Net business profits (losses) + Net gains (losses) related to ETFs and others” for the fiscal years ended March 31, 2022, 2023 and 2024 presented above to income (loss) before income tax expense (benefit) shown on the consolidated statements of income and a reconciliation of “Fixed assets” at March 31, 2023 and 2024 to the total amount of Premises and equipment-net, right-of-use 2022 2023 2024 (in billions of yen) Net business profits (losses) + Net gains (losses) related to ETFs and others 853.1 807.1 1,005.8 Adjustment to reconcile management reporting to Japanese GAAP: General and administrative expenses: non-allocated 33.7 39.7 28.6 Expenses related to portfolio problems (including reversal of (provision for) general reserve for losses on loans) (255.9 ) (96.7 ) (114.0 ) Gains on reversal of reserves for possible losses on loans, and others 20.8 7.4 7.6 Net gains (losses) related to stocks—Net gains (losses) related to ETFs and others (45.8 ) 84.6 54.7 Net extraordinary gains (losses) 44.0 (10.6 ) 40.9 Others (46.1 ) (52.5 ) (68.8 ) Income before income tax expense under Japanese GAAP   603.9   779.0   955.0 Adjustment to reconcile Japanese GAAP to U.S. GAAP: Derivative financial instruments and hedging activities (124.0 ) (373.2 ) 50.5 Investments (600.1 ) (210.5 ) 571.7 Loans (18.3 ) (30.3 ) (8.8 ) Allowances for credit losses 51.5 (9.8 ) 25.3 Premises and equipment (68.5 ) (29.3 ) (55.1 ) Land revaluation 6.4 5.6 4.9 Business combinations 6.9 8.9 10.8 Pension liabilities (94.4 ) (71.6 ) (60.4 ) Consolidation of variable interest entities 42.3 0.8 211.2 Foreign currency translation (51.0 ) (5.2 ) (83.2 ) Others 2.8 4.8 0.9 Income (loss) before income tax expense (benefit) under U.S. GAAP (242.5 ) 69.2 1,623.1 2022 2023 2024 (in billions of yen) Fixed assets 1,697.2 1,678.5 1,864.6 U.S. GAAP adjustments (Note) 717.6 662.6 582.2 Premises and equipment-net, right-of-use 2,414.9   2,341.2   2,446.9   Note: The U.S. GAAP adjustments are primarily comprised of GAAP differences mainly from right-of-use

Foreign activities

Foreign activities	12 Months Ended
	Mar. 31, 2024
Text Block [Abstract]
Foreign activities	31. Foreign activities The following table presents consolidated income statement and total assets information by major geographic area. Foreign activities are defined as business transactions that involve customers residing outside of Japan. However, as the MHFG Group’s operations are highly integrated globally, estimates and assumptions have been made for an allocation among the geographic areas. Americas Japan United States of America Others Europe Asia/Oceania excluding Japan, and others Total (in billions of yen) Fiscal year ended March 31, 2022: Total revenue (1) 991.1 562.9 41.7 184.8 333.2 2,113.7 Total expenses (2) 1,713.8 265.0 19.0 189.2 169.2 2,356.2 Income (loss) before income tax expense (benefit) (722.7 ) 297.9 22.7 (4.4 ) 164.0 (242.5 ) Net income (loss) (509.0 ) 275.2 18.3 (16.3 ) 130.3 (101.5 ) Total assets at end of fiscal year 155,111.2 36,765.7 3,667.9 15,795.9 20,210.0 231,550.7 Fiscal year ended March 31, 2023: Total revenue (1) 1,104.7 1,841.5 93.1 445.9 791.7 4,276.9 Total expenses (2) 1,784.1 1,455.4 84.7 413.0 470.5 4,207.7 Income (loss) before income tax expense (benefit) (679.4 ) 386.1 8.4 32.9 321.2 69.2 Net income (loss) (554.7 ) 297.2 1.8 19.9 269.8 34.0 Total assets at end of fiscal year 161,348.7 45,516.4 3,579.6 16,634.7 21,701.3 248,780.7 Fiscal year ended March 31, 2024: Total revenue (1) 2,827.1 3,584.4 198.5 803.7 1,097.1 8,510.7 Total expenses (2) 2,171.8 2,978.7 191.6 817.1 728.4 6,887.6 Income (loss) before income tax expense 655.3 605.6 6.8 (13.3 ) 368.6 1,623.1 Net income (loss) 449.0 491.1 (1.6 ) (50.0 ) 309.5 1,198.0 Total assets at end of fiscal year 170,063.8 57,036.0 4,483.0 19,142.1 21,448.2 272,173.2 Notes: (1) Total revenue is comprised of Interest and dividend income and Noninterest income. (2) Total expenses are comprised of Interest expense, Provision (credit) for credit losses and Noninterest expenses.

Mizuho Financial Group, Inc., p

Mizuho Financial Group, Inc., parent company	12 Months Ended
	Mar. 31, 2024
Condensed Financial Information Disclosure [Abstract]
Mizuho Financial Group, Inc., parent company	32. Mizuho Financial Group, Inc., parent company The following tables present the parent company only financial information of MHFG: Condensed balance sheets 2023 2024 (in millions of yen) Assets: Cash and due from banking subsidiaries 47,425 23,394 Interest-bearing deposits in banking subsidiaries 450 431 Investments in subsidiaries and affiliated companies: Banking subsidiaries 7,996,767 8,542,884 Non-banking 1,075,322 1,305,643 Long-term loans receivable from subsidiaries: A banking subsidiary 8,768,725 9,567,224 A non-banking 444,000 444,000 Other assets 545,744 629,277 Total 18,878,433 20,512,853 Liabilities and shareholders’ equity: Short-term borrowings from a banking subsidiary 810,000 631,000 Long-term debt 8,741,729 9,546,009 Other liabilities 411,213 406,773 Shareholders’ equity 8,915,491 9,929,071 Total 18,878,433 20,512,853 Condensed statements of income 2022 2023 2024 (in millions of yen) Income: Dividends from subsidiaries and affiliated companies: Banking subsidiaries 197,717 209,257 547,487 Non-banking 82,105 62,698 11,826 Management fees from subsidiaries 40,462 43,900 51,770 Interest income on loans and discounts 133,215 177,137 232,272 Gains on sales of investments in subsidiaries 53,005 —  —  Other income 11,319 37,319 4,444 Total   517,823   530,311 847,800 Expenses: Operating expenses 43,192 52,887 60,037 Interest expense 130,453 175,723 230,780 Losses on sales of investments in a subsidiary 26,606 —  —  Other expense 5,946 2,768 11,286 Total 206,197 231,378 302,103 Equity in undistributed net income (loss) of subsidiaries and affiliated companies—net (505,891 ) (307,879 ) 365,266 Income (loss) before income tax expense (benefit) (194,265 ) (8,946 ) 910,964 Income tax expense (benefit) (89,543 ) 5,063 (1,509 ) Net income (loss) (104,722 ) (14,009 ) 912,473 MIZUHO FINANCIAL GROUP, INC. AND SUBSIDIARIES Condensed statements of cash flows 2022 2023 2024 (in millions of yen) Cash flows from operating activities: Net income (loss) (104,722 ) (14,009 ) 912,473 Adjustments and other 351,484 394,191 (421,191 ) Net cash provided by operating activities 246,762 380,182 491,282 Cash flows from investing activities: Net change in loans (72,313 ) (511,934 ) (130,719 ) Purchases of investments in subsidiaries —  (179,210 ) (91,200 ) Proceeds from sales of investments in subsidiaries 452,500 721 —  Net change in other investing activities 208 (5,673 ) (9,983 ) Net cash provided by (used in) investing activities 380,395 (696,095 ) (231,902 ) Cash flows from financing activities: Net change in short-term borrowings (95,000 ) 55,000 (179,000 ) Proceeds from issuance of long-term debt 930,033 1,497,032 1,363,655 Repayment of long-term debt (1,256,720 ) (1,030,099 ) (1,232,936 ) Purchases of treasury stock (1,927 ) (1,575 ) (2,478 ) Dividends paid (196,783 ) (209,457 ) (234,787 ) Net change in other financing activities 44 1,117 2,116 Net cash provided by (used in) financing activities (620,353 ) 312,018 (283,431 ) Net increase (decrease) in cash and cash equivalents 6,804 (3,895 ) (24,050 ) Cash and cash equivalents at beginning of fiscal year 44,966 51,770 47,875 Cash and cash equivalents at end of fiscal year 51,770 47,875 23,825

Basis of presentation and sum_2

Basis of presentation and summary of significant accounting policies (Policies)	12 Months Ended
	Mar. 31, 2024
Basis of presentation	Basis of presentation Mizuho Financial Group, Inc. (“MHFG”) is a joint stock corporation with limited liability under the laws of Japan. MHFG is a holding company for Mizuho Bank, Ltd. (“MHBK”), Mizuho Trust & Banking Co., Ltd. (“MHTB”), Mizuho Securities Co., Ltd. (“MHSC”), Asset Management One Co., Ltd. (“Asset Management One”), and other subsidiaries. MHFG, through its subsidiaries (“the MHFG Group,” or “the Group”), provides domestic and international financial services in Japan and other countries. For a discussion of the Group’s segment information, see Note 30 “Business segment information.” MHFG and its domestic subsidiaries as well as its foreign subsidiaries maintain their accounting records in accordance with the accounting standards of Japan and those standards of the countries in which they are domiciled. Certain adjustments and reclassifications have been incorporated in the accompanying consolidated financial statements to conform them to the accounting principles generally accepted in the United States of America (“U.S. GAAP”). The consolidated financial statements are stated in Japanese yen, the currency of the country in which MHFG is incorporated and principally operates. The accompanying consolidated financial statements include the accounts of MHFG and its subsidiaries. MHFG’s fiscal year ends on March 31. MHFG’s subsidiaries fiscal year end is determined by each subsidiary. If the fiscal year end of a subsidiary has more than three months discrepancy from the MHFG’s fiscal year end, the subsidiary executes provisional financial closing. For those subsidiaries where the fiscal year end is not on March 31 and where the subsidiaries do not execute provisional financial close, the effect on the MHFG Group’s consolidated financial statements of all material events through the date of each of the periods presented in the consolidated financial statements has been considered for adjustment and/or disclosure. When determining whether to consolidate investee entities, the MHFG Group performs an analysis of the facts and circumstances of the particular relationships between the MHFG Group and the investee entities as well as the ownership of voting shares. The consolidated financial statements also include the accounts of VIEs for which MHFG or its subsidiaries have been determined to be the primary beneficiary in accordance with the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 810, “Consolidation” (“ASC 810”). All significant intercompany transactions and balances have been eliminated upon consolidation. The MHFG Group accounts for investments in entities over which it has significant influence by using the equity method of accounting. These investments are included in Other investments and the Group’s proportionate share of income or loss is included in Equity in earnings (losses) of equity method investees—net. Certain comparative amounts for the prior period have been reclassified in order to conform to the current period’s presentation.
Use of estimates	Use of estimates The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect reported amounts and related disclosures. Specific areas, among others, requiring the application of management’s estimates and judgment include assumptions pertaining to the allowance for credit losses, valuation of loans held-for-sale,
Definition of cash and cash equivalents	Definition of cash and cash equivalents For purposes of the consolidated statements of cash flows, Cash and cash equivalents consists of Cash and due from banks and Interest-bearing deposits in other banks. Cash deposited with central banks that must be maintained to meet minimum regulatory requirements is classified as restricted cash and included in Cash and cash equivalents. See Note 8 “Pledged assets and collateral” for more information on restricted cash.
Translation of foreign currency financial statements and foreign currency transactions	Translation of foreign currency financial statements and foreign currency transactions Financial statements of overseas entities are prepared using the functional currency of each entity and translated into Japanese yen for consolidation purposes. Assets and liabilities are translated using the fiscal-year-end Foreign currency translation gains and losses related to the financial statements of overseas entities of the MHFG Group, net of related income tax effects, are credited or charged directly to Foreign currency translation adjustments, a component of Accumulated other comprehensive income (loss), net of tax (“AOCI”). The tax effects of gains and losses related to the foreign currency translation of financial statements of overseas entities are not recognized unless it is apparent that the temporary differences will reverse in the foreseeable future. Assets and liabilities of domestic and overseas entities denominated in foreign currencies are remeasured into the functional currency of the respective entity at the fiscal year-end
Call loans and call money	Call loans and call money Call loans and call money represent lending/borrowing, primarily through the Japanese short-term money market, to/from other financial institutions such as banks, insurance companies, and securities brokerage houses.
Repurchase and resale agreements, securities lending and borrowing and other secured financing transactions	Repurchase and resale agreements, securities lending and borrowing and other secured financing transactions Securities sold under agreements to repurchase (“repurchase agreements”), securities purchased under agreements to resell (“resale agreements”) and securities lending and borrowing transactions are accounted for as secured financing or lending transactions when control over the underlying securities is not deemed to be surrendered by the transferor. Otherwise, they are recorded as sales of securities with related forward repurchase commitments or purchases of securities with related forward resale commitments in accordance with ASC 860, “Transfers and Servicing” (“ASC 860”). Under resale agreements, securities borrowing and certain derivatives transactions, the MHFG Group receives collateral in the form of securities. In many cases, the MHFG Group is permitted to sell or repledge the securities obtained as collateral. Disclosures in respect of such collateral are presented in Note 8 “Pledged assets and collateral.” With respect to repurchase agreements, securities lending, and certain derivative transactions, counterparties may have the right to sell or repledge securities that the MHFG Group has pledged as collateral. The MHFG Group separately discloses these pledged securities in the consolidated balance sheets. The MHFG Group monitors credit exposure arising from resale agreements, repurchase agreements, securities borrowing and securities lending transactions on a regular basis, and additional collateral is obtained from or returned to counterparties, as appropriate.
Trading securities and trading securities sold, not yet purchased	Trading securities and trading securities sold, not yet purchased Trading securities consist of securities and money market instruments that are bought and held principally for the purpose of reselling in the near term with the objective of generating profits on short-term fluctuations in price. Trading securities sold, not yet purchased, are securities and money market instruments sold to third parties that the MHFG Group does not own and is obligated to purchase at a later date to cover the short position. Trading securities and trading securities sold, not yet purchased, are recorded on the trade date. Trading securities and trading securities sold, not yet purchased, are recorded at fair value in the consolidated balance sheets in Trading account assets and Trading account liabilities with realized and unrealized gains and losses recorded on a trade date basis in Trading account gains (losses)—net in the consolidated statements of income. Interest and dividends on trading securities, including securities sold, not yet purchased, are recorded in Interest and dividend income or Interest expense on an accrual basis.
Investments	Investments Debt securities that the MHFG Group has both the positive intent and ability to hold to maturity are classified as Held-to-maturity Available-for-sale At the end of each reporting period the MHFG Group performs a review to identify impaired available-for-sale available-for-sale first-in first-out Other investments include marketable and non-marketable non-marketable
Derivative financial instruments	Derivative financial instruments Derivative financial instruments are bought and held principally for the purpose of market making for customers, proprietary trading in order to generate trading revenues and fee income, and also to manage the MHFG Group’s exposure to interest rate, credit and market risks related to asset and liability management. Such derivative financial instruments include interest rate, foreign currency, equity, commodity and credit default swap agreements, options, caps and floors, and financial futures and forward contracts. Derivatives bought and held for trading purposes are recorded in the consolidated balance sheets at fair value in Trading account assets and Trading account liabilities. The fair values of derivatives in a gain position and a loss position are reported as Trading account assets and Trading account liabilities, respectively. Derivatives used for asset and liability management include contracts that qualify for hedge accounting under ASC 815, “Derivatives and Hedging” (“ASC 815”). To be eligible for hedge accounting, derivative instruments must be highly effective in achieving offsetting changes in fair values or variable cash flows of the hedged items attributable to the particular risk being hedged. All qualifying hedging derivatives are valued at fair value and included in Trading account assets or Trading account liabilities. Derivatives that do not qualify for hedge accounting under ASC 815 are treated as trading positions and are accounted for as such. The fair value amounts recognized for all derivatives are presented on a gross basis and not offset against the amounts recognized for the right to reclaim cash collateral or the obligation to return cash collateral under the master netting agreement with the same counterparty. The fair values of derivative financial instruments are determined based on quoted market prices or broker-dealer quotes, if available. If not available, the fair values are estimated using quoted market prices for similar instruments, option or binomial pricing models or a present value cash flow analysis, utilizing current observable market information, where available. In determining the fair values, the Group considers various factors such as exchange or over-the-counter Changes in the fair values of all derivatives are recorded in earnings, except for derivatives qualifying as net investment hedges under ASC 815 which are recorded in AOCI. The changes in the fair values of all derivatives relating to foreign currency exchange rates are included in Foreign exchange gains (losses)—net and Trading account gains (losses)—net. Other elements of the changes in the fair values, including interest rate, equity and credit related components, except these of certain credit derivatives hedging the credit risk in the corporate loan portfolio, are recognized in Trading account gains (losses)—net. The net gain (loss) resulting from changes in the fair values of certain credit derivatives where the Group purchases protection to mitigate its credit risk exposure related to its corporate loan portfolio is recorded in Other noninterest income (expenses). Certain financial and hybrid instruments often contain embedded derivative instruments that possess implicit or explicit contract terms similar to those of a derivative instrument. Such derivative instruments are required to be fair-valued separately from the host contracts if they meet the bifurcation criteria of an embedded derivative. Such criteria include that the entire instrument is not marked to market through earnings, the economic characteristics and risks of the embedded contract terms are not clearly and closely related to those of the host contract and the embedded contract terms would meet the definition of a derivative on a stand-alone basis.
Loans	Loans Loans are generally carried at the principal amount adjusted for unearned income and deferred net nonrefundable loan fees and costs. Loan origination fees, net of certain direct origination costs, are deferred and recognized over the contractual life of the loan as an adjustment of yield using a method that approximates the interest method. Interest income on performing loans is accrued and credited to income as it is earned. Unearned income and discounts or premiums on purchased loans are deferred and recognized over the life of the loan using a method that approximates the interest method. Loans are considered nonaccrual when, based on current information and events, it is probable that the MHFG Group will be unable to collect all the scheduled payments of principal and interest when due according to the contractual terms of the loans. Factors considered by management in determining if a loan is nonaccrual include delinquency status and the ability of the debtor to make payments of the principal and interest when due. Nonaccrual loans include loans past due for 90 days or more and modified loans to borrowers experiencing financial difficulty. The majority of nonaccrual loans have no contractual delinquency due to interest reductions and/or postponement of principal and interest. In case loans are designated as nonaccrual loans, interest accruals and the amortization of net origination fees are suspended and capitalized interest is written off. Cash received on nonaccrual loans is accounted for as a reduction of the loan principal if the ultimate collectability of the principal amount is in doubt, otherwise, as interest income. Loans are not restored to accrual status until interest and principal payments are current and future payments are reasonably assured. Nonaccrual loans are restored to accrual loans and accrual status, when the MHFG Group determines that the borrower poses no concerns regarding current certainty of debt fulfillment. In general, such determination is made if the borrower qualifies for an obligor rating of E2 or above and is not classified as a special attention obligor. With respect to modified loans to borrowers experiencing financial difficulty, in general, such loans are restored to accrual loans, and accrual status, when the borrower qualifies for an obligor rating of D or above. See Note 4 “Loans” for the definitions of obligor ratings. Loans that have been identified for sale are classified as loans held for sale within Other assets and are accounted for at the lower of cost or fair value on an individual loan basis, with valuation changes recorded in Other noninterest income and expenses. If management decides to retain certain loans held for sale for the foreseeable future or until maturity or payoff, such items are transferred to Loans at the lower of cost or fair value.
Financial instruments—current expected credit losses ("CECL")	Financial instruments—current expected credit losses (“CECL”) CECL established a single allowance framework for all financial assets measured at amortized cost and certain off-balance-sheet available-for-sale
Allowance and provision (credit) for credit losses on loans	Allowance and provision (credit) for credit losses on loans Each reporting period, the MHFG Group makes adjustments to the allowance for credit losses on loans through Provision (credit) for credit losses in the consolidated statements of income. Loan principal that management judges to be uncollectible, based on detailed loan reviews and a credit quality assessment, is charged off against the allowance for credit losses on loans. In general, the Group charges off loans when the Group determines that the obligor should be classified as substantially bankrupt or bankrupt. See Note 4 “Loans” for the definitions of obligor categories. Obligors in the retail portfolio segment are generally determined to be substantially bankrupt when they are past due for more than six months, and as for obligors in the corporate portfolio segment, the Group separately monitors the credit quality of each obligor without using time-based triggers. The MHFG Group maintains an appropriate allowance for credit losses on loans to represent management’s estimate of the expected credit losses in the Group’s loan portfolio. Management evaluates the appropriateness of the allowance for credit losses on loans semi-annually. The allowance considers expected credit losses over the remaining expected lives of the applicable instruments. The expected life of each instrument is determined by considering expected prepayments, contractual terms and cancellation features. The allowance for credit losses involves significant judgments on a number of matters including expectations of future economic conditions, assignment of obligor ratings, valuation of collateral, and the development of qualitative adjustments. When determining expected credit losses, a single forward-looking macroeconomic scenario is considered over a reasonable and supportable forecast period. This forward-looking macroeconomic scenario is in line with the scenario used for the Group’s business plan. If the scenarios are not reflective of management’s expectations, adjustments may be made to the scenarios. After the forecast period, the Group reverts to long-term historical loss experience with a certain graduated transition period, to estimate losses over the remaining lives of financial assets measured at amortized cost and certain off-balance-sheet In terms of the internal risk ratings, for the corporate portfolio segment, the credit quality review process and the credit rating process serve as the basis for determining the allowance for credit losses on loans. Through such processes, loans are categorized into groups to reflect the probability of default, whereby the MHFG Group’s management assesses the ability of borrowers to service their debt, taking into consideration current financial information, ability to generate cash, historical payment experience, analysis of relevant industry segments and current trends. For the retail portfolio segment, the different categories of past due status of loans are primarily utilized in the credit quality review and the credit rating processes as the basis for determining the allowance for credit losses on loans. In general, the MHFG Group estimates expected credit losses collectively on the loans in the case of normal and watch obligors, considering the risk associated with a particular pool and the probability that the exposures within the pool will deteriorate or default. The allowance for credit losses on nonaccrual loans generally includes the allowance for those loans that were individually evaluated for expected credit losses. See Note 4 “Loans” for the definitions of obligor categories and classification of nonaccrual loans. The estimation of expected credit losses that are evaluated collectively begins with a quantitative calculation that considers the likelihood of the borrower changing delinquency status or moving from one obligor category or rating to another. The quantitative calculation covers expected credit losses over an instrument’s expected life and is estimated by applying credit loss factors to the MHFG Group’s estimated exposure at default. The credit loss factors incorporate the probability of default as well as the loss given default based on the historical loss rates. To supplement the historical loss data for overseas obligors, external credit ratings such as S&P are also used to calculate the probability of default. The model and inputs used to determine credit losses on loans that are evaluated collectively are analyzed on a periodic basis by comparing the estimated values with the actual results subsequent to the balance sheet date. The MHFG Group divides its overall portfolio into domestic and foreign portfolios and categorizes the domestic portfolio into four portfolio segments according to their risk profiles: corporate, retail, sovereign, and banks and financial institutions. The corporate portfolio segment consists of loans originated primarily by MHBK and MHTB, and includes mainly business loans such as those used for working capital and capital expenditure, as well as loans for which the primary source of repayment of the obligation is income generated by the relevant assets such as project finance, asset finance and real estate finance. The corporate portfolio segment is divided into two classes based on their risk characteristics: large companies, and small and medium-sized The retail portfolio segment consists mainly of residential mortgage loans originated by MHBK, and it is divided into two classes based on their risk characteristics: housing loans and others. For the retail portfolio segment, the Japanese unemployment rate is applied as a key factor. As it pertains to modified loans to borrowers experiencing financial difficulty in the retail portfolio segment, the restructuring itself, as well as subsequent payment defaults, if any, are considered in determining obligor categories. Expected credit loss estimates also include consideration of expected cash recoveries on loans previously charged-off, The allowance recorded for individually evaluated loans is based on (1) the present value of expected future cash flows, after considering the restructuring effect and subsequent payment default with respect to modified loans to borrowers experiencing financial difficulty, discounted at the loan’s post-modification contractual effective interest rate, (2) the loan’s observable market price, or (3) the fair value of the collateral if the loan is collateral dependent. The collateral that the MHFG Group obtains for loans consists primarily of real estate. In obtaining the collateral, the Group evaluates the fair value of the collateral and its legal enforceability. The Group also performs subsequent re-evaluations The MHFG Group’s methodology for determining the appropriate allowance for credit losses on loans also considers the imprecision inherent in the methodologies used. As a result, the amounts determined under the methodologies described above could be adjusted by management to consider the potential impact of other qualitative factors which include, but are not limited to, imprecision in macroeconomic scenario assumptions and emerging risks related to changes in the environment that affect specific portfolio segments including segments impacted by the Russia-Ukraine situation. Considering internal and external factors affecting the credit quality of the portfolio, the Group incorporated the estimated impact of the Russia-Ukraine situation, interest rates hike on domestic obligors and other factors contributing to economic uncertainty into the macroeconomic scenario by using assumptions such as the future outlook of the business environment for specific portfolio segments and the current forecast for the growth rate of gross domestic product. In terms of the Russia-Ukraine situation, considering the country risk arising from the continued sanctions against Russia and the downgrading of their credit rating, the MHFG Group incorporated the estimated impact of the Russia-Ukraine situation into the macroeconomic scenario used for determining the allowance for credit losses on loans.
Allowance and provision (credit) for credit losses on off-balance-sheet instruments	Allowance and provision (credit) for credit losses on off-balance-sheet The MHFG Group maintains an allowance for credit losses on off-balance-sheet allowance for credit losses on off-balance-sheet off-balance-sheet
Allowance and provision (credit) for credit losses on available-for-sale securities	Allowance and provision (credit) for credit losses on available-for-sale The MHFG Group performs periodic reviews to identify impaired securities in accordance with ASC 326. Available-for-sale available-for-sale available-for-sale
Premises and equipment	Premises and equipment Premises and equipment are stated at historical cost, and depreciation and amortization are recorded over the estimated useful lives of the assets, except for leasehold improvements, which are amortized over the shorter of the estimated useful lives of the assets or the lease term. Depreciation and amortization are principally computed in accordance with the straight-line method with respect to buildings and leasehold improvements and in accordance with the declining-balance method with respect to other premises and equipment. The useful lives of premises and equipment are as follows: Years Buildings 3 to 50 Equipment and furniture 2 to 20 Regular repairs and maintenance costs that do not extend the estimated useful life of an asset are charged to expense as incurred. Upon sale or disposition of premises and equipment, the cost and related accumulated depreciation or amortization are removed from the accounts, and any gains or losses on disposal are included in Gains on disposal of premises and equipment or Occupancy expenses.
Impairment of long-lived assets	Impairment of long-lived assets The MHFG Group’s long-lived assets that are held for use are reviewed periodically for events or changes in circumstances that indicate possible impairment. The Group’s impairment review is based on an undiscounted cash flow analysis of a group of assets, combined with associated liabilities, at the lowest level for which identifiable cash flows exist. Impairment occurs when the carrying value of the asset group exceeds the future undiscounted cash flows that the asset group is expected to generate. When impairment is identified, the future cash flows are then discounted to determine the estimated fair value of the asset group and an impairment charge is recorded for the difference between the carrying value and the estimated fair value of the asset group. The long-lived assets to be disposed of by sale are carried at the lower of the carrying amount or fair value, less estimated cost to sell.
Software	Software Internal and external costs incurred in connection with developing and obtaining software for internal use during the application development stage are capitalized. Such costs include salaries and benefits for employees directly involved with and who devote time to the project, to the extent such time is incurred directly on the internal use software project. The capitalization of software ceases when the software project has been substantially completed. The capitalized software is amortized on a straight-line basis over the estimated useful life, generally 5 to 10 years. Internal use software is reviewed for impairment whenever events or changes in circumstances indicate that its carrying amount may not be recoverable.
Goodwill	Goodwill Goodwill represents the excess of the total fair value of the acquired company, which consists of the consideration transferred, the fair value of any interest in the acquiree already held by the acquirer and the fair value of any noncontrolling interest in the acquiree over the fair value of net identifiable assets acquired at the date of acquisition in a business combination. The MHFG Group accounts for goodwill in accordance with ASC 350, “Intangibles—Goodwill and Other” (“ASC 350”). Goodwill is recorded at a designated reporting unit level for the purpose of assessing impairment. Goodwill is not amortized but is tested for impairment at least annually or more often if events or circumstances indicate there may be impairment. For both the annual and interim tests, the Group has the option to either (a) perform a quantitative impairment test or (b) first perform a qualitative assessment to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount, in which case the Group would perform the quantitative test. An impairment loss is recorded to the extent the carrying amount of goodwill exceeds its estimated fair value. The estimated fair value of the reporting units is derived based on valuation techniques that the Group believes market participants would use for each of the reporting units. The Group generally determines the estimated fair value by utilizing a discounted cash flow methodology or methodologies that incorporate price-to-book
Intangible assets	Intangible assets Intangible assets having definite useful lives are amortized over their estimated useful lives on either a straight-line basis or the method that reflects the pattern in which the economic benefits of the intangible assets are consumed. Intangible assets acquired in connection with the merger of MHSC and Shinko Securities Co., Ltd. (“Shinko”) and the integration of asset management functions of DIAM Co., Ltd. (“DIAM”), MHTB, Mizuho Asset Management Co., Ltd. (“MHAM”) and Shinko Asset Management Co., Ltd. (“Shinko Asset Management”) consist primarily of customer relationship intangibles, and are amortized over weighted-average amortization periods of 16 years and 16.9 years, respectively. Intangible assets having indefinite useful lives are not amortized and are subject to impairment tests. An impairment loss is recorded to the extent that the carrying amount of the indefinite-lived intangible asset exceeds its estimated fair value. For intangible assets subject to amortization, an impairment loss is recorded if the carrying amount is not recoverable and exceeds its estimated fair value.
Leases	Leases The MHFG Group, as a lessee, recognizes liabilities to make lease payments and right-of-use elected not to separate lease and non-lease right-of-use right-of-use right-of-use right-of-use
Pension and other employee benefits	Pension and other employee benefits MHFG and certain subsidiaries sponsor pension plans which provide defined benefits to retired employees and other postretirement benefit plans, including severance indemnities. Severance indemnities are amounts payable to eligible employees upon termination of employment and are payable as a lump sum. Periodic expense and accrued liabilities are computed based on the actuarial present value of benefits, net of investment returns expected from plan assets and their fair values at the balance sheet date. Net periodic expense is charged to Salaries and employee benefits. Net actuarial gains and losses that arise from differences between actual experience and assumptions are generally amortized over
Stock-based compensation	Stock-based compensation MHFG, MHBK, MHTB and MHSC have stock options, in the form of stock acquisition rights, for directors (excluding the outside directors) and executive officers of the respective companies (hereinafter referred to collectively as the “Directors”). In this plan (“the MHFG Group’s Stock Plan”), 100 shares of MHFG common stock shall be issued or transferred upon exercise of each of the stock acquisition rights. The exercise price is 1 yen per share. The contractual term of the stock acquisition rights is 20 years. A holder may exercise the stock acquisition rights only after the date on which such holder loses the status as a Director of MHFG, MHBK, MHTB or MHSC. In May 2015, the MHFG Group discontinued the stock option program. Thereafter, the MHFG Group has not issued any new stock options. MHFG, MHBK, MHTB and MHSC have a responsibility-based stock compensation program for Directors (“Stock Compensation I”) and a performance-based stock compensation program for Directors (“Stock Compensation II”). MHFG and certain consolidated subsidiaries introduced both responsibility-based and performance-based stock compensation program for Operating Officers (“Stock Benefit”) in July 2021. For these programs, the stock-based compensation cost is determined based on the fair value of MHFG’s common stock as of grant date. The liability related to the cash-based compensation cost is remeasured at each reporting date based on the fair value of MHFG’s common stock. For Stock Compensation I, as the program is effectively vested on the grant date, the stock-based compensation cost is recognized on the grant date. For Stock Compensation II, the stock-based compensation costs are recognized evenly over the graded-vesting period, which is three years. For Stock Benefit, the stock-based compensation costs are recognized evenly over the vesting period, which is one year. Those Stock options and Stock Compensation plans did not have a material impact on the MHFG Group’s consolidated results of operations or financial condition.
Long-term debt	Long-term debt Premiums, discounts and issuance costs of long-term debt are amortized based on a method that approximates the interest method over the respective terms of the long-term debt.
Obligations under guarantees	Obligations under guarantees The MHFG Group provides customers with a variety of guarantees and similar arrangements, including standby letters of credit, financial and performance guarantees, credit protection, and liquidity facilities. The MHFG Group recognizes guarantee fee income over the guarantee period. The MHFG Group receives such a guarantee fee at the inception of the guarantee or in installments and, in either case, the present value of the total fees approximates the fair value of the guarantee.
Fair Value Measurements	Fair Value Measurements The MHFG Group carries certain of its financial assets and liabilities at fair value on a recurring basis. These financial assets and liabilities are primarily composed of trading account assets, trading account liabilities, available-for-sale non-recurring Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. In accordance with ASC 820, “Fair Value Measurement” (“ASC 820”), the Group classifies its financial assets and liabilities into the fair value hierarchy (Level 1, 2, and 3). See Note 26 “Fair value” for the detailed definition of each level. When determining fair value, the MHFG Group considers the principal or most advantageous market in which the Group would transact and considers assumptions that market participants would use when pricing the asset or liability. The Group maximizes the use of observable inputs and minimizes the use of unobservable inputs when measuring fair value. See Note 26 “Fair value” for descriptions of valuation methodologies used for its assets and liabilities by product.
Fee and commission income	Fee and commission income The MHFG Group recognizes revenue from contracts with customers in an amount that reflects the consideration to which the Group expects to be entitled in exchange for transferring control of a promised service. The timing of revenue recognition is dependent on whether the Group satisfies a performance obligation by transferring control of the service to a customer over time or at a point in time. Fee and commission income is presented exclusive of consumption taxes. The major components of fee and commission income are as follows. Securities-related business fees mainly consist of brokerage fees and commissions, and asset-based revenues. Brokerage fees and commissions mainly include fees earned from the execution of customer transactions and sales commissions of stocks, bonds and investment trusts. Brokerage fees and commissions are recognized at the point in time on transaction date. Asset-based revenues mainly include fees received from investment trust management companies in return for administration services, such as record keeping services, of investment trusts. The amounts of asset-based revenues are calculated based on customer’s net asset value and recognized over time in the period when the related service is provided. Deposit-related fees include service charges on consumer and commercial deposit accounts such as account transfer charges. Deposit-related fees are recognized at the point in time when the transactions occur, or the related service is provided. Lending-related fees include fees for lending business such as commitment fees and arrangement fees. Remittance business fees include service charges for domestic and international funds transfers and collections. These fees are recognized at the point in time when the related service is provided. Asset management business fees consist of investment trust management fees and investment advisory fees for investment trusts. These fees are received from investment trusts in return for asset management services and/or investment advisory services on behalf of customers. The amounts of these fees are calculated based on a percentage of customer’s net asset value. These fees are recognized over time in the period when the management and/or advisory service is provided and the amount is fixed. Trust-related business fees consist of trust fees earned primarily through fiduciary asset management and administrative service and other trust-related fees. Fees for fiduciary asset management and administration services for corporate pension plans and investment funds are recognized at the point on creation of the trust or completion date specified in the contract, or over time in the period when the related service is provided. Other trust-related fees mainly include brokerage commissions of real estate property, sales commissions of beneficial interest in real estate trust, consulting fees of real estate property and charges for stock transfer agent services. These fees are mainly earned on a transaction basis and recognized at the point in time when the related service is provided or over time in the period when the related service is provided. Agency business fees mainly include administration service fees related to the MHFG Group’s agency business such as Japan’s principal public lottery program and revenues from standing proxy services related to stocks and others. These fees are recognized at the point in time when the related service is provided or over time in the period when the related service is provided. Fees for other customer services include various revenues such as sales commissions of life insurance, service charges for electronic banking, financial advisory fees, and service charges for software development. Sales commissions from life insurance sales are received from insurance companies in return for selling insurance products and recognized when the insurance product is sold to customers. Service charges for electronic banking are mainly monthly basic usage fees and recognized over the related transaction period. Financial advisory fees are received as consideration for services supporting market research and business strategy planning, which are recognized over time in the period when the related advisory service based on the contract is rendered. Service charges for software development are recognized over time according to the progress of the development.
Fee and commission expenses	Fee and commission expenses The principal items included in fee and commission expenses are fee and commission expenses for remittance services and brokerages fees paid for securities transactions. These expenses are generally recognized on an incurred basis.
Income taxes	Income taxes Income taxes are accounted for in accordance with ASC 740, “Income Taxes” (“ASC 740”). Deferred income taxes reflect the net tax effects of (1) temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the corresponding amounts used for income tax purposes, and (2) operating loss and tax credit carryforwards. A valuation allowance is recorded for any portion of the deferred tax assets unless it is more likely than not that the deferred tax assets will be realized. Deferred income tax benefit or expense is recognized for the changes in the net deferred tax asset or liability between periods.
Earnings per common share	Earnings per common share Basic earnings per common share are computed by dividing net income ( loss

Basis of presentation and sum_3

Basis of presentation and summary of significant accounting policies (Tables)	12 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Useful Lives of Premises and Equipment	The useful lives of premises and equipment are as follows: Years Buildings 3 to 50 Equipment and furniture 2 to 20

Investments (Tables)

Investments (Tables)	12 Months Ended
	Mar. 31, 2024
Amortized Cost, Gross Unrealized Gains and Losses, and Fair Value of Available-for-Sale and Held-to-Maturity Securities	The amortized cost, net of allowance for credit losses, gross unrealized gains and losses, and fair value of available-for-sale held-to-maturity Amortized cost (4)(5) Gross unrealized gains Gross unrealized losses Fair value (in millions of yen) 2023 Available-for-sale Debt securities: Japanese government bonds 16,483,722 3,067 37,496 16,449,293 Japanese local government bonds 560,093 198 5,628 554,663 U.S. Treasury bonds and federal agency securities 382,990 —  7,289 375,701 Other foreign government bonds 1,309,473 661 2,261 1,307,873 Agency mortgage-backed securities (1) 532,364 1,140 11,307 522,197 Residential mortgage-backed securities 48,257 71 866 47,462 Commercial mortgage-backed securities 856,708 5,157 451 861,414 Japanese corporate bonds and other debt securities 2,100,733 13,024 4,538 2,109,219 Foreign corporate bonds and other debt securities (2) 1,005,209 2,319 1,581 1,005,947 Total 23,279,549 25,637 71,417 23,233,769 Held-to-maturity Debt securities: Japanese government bonds 799,305 2,171 1,028 800,448 Agency mortgage-backed securities (3) 1,250,802 403 136,545 1,114,660 Total 2,050,107 2,574 137,573 1,915,108 Amortized cost (4)(5) Gross unrealized gains Gross unrealized losses Fair value (in millions of yen) 2024 Available-for-sale Debt securities: Japanese government bonds 10,968,212 9,137 2,956 10,974,393 Japanese local government bonds 591,218 95 7,574 583,739 U.S. Treasury bonds and federal agency securities 147,186 118 252 147,052 Other foreign government bonds 2,044,611 1,739 1,755 2,044,595 Agency mortgage-backed securities (1) 495,057 140 18,225 476,972 Residential mortgage-backed securities 32,120 30 767 31,383 Commercial mortgage-backed securities 800,224 4,787 789 804,222 Japanese corporate bonds and other debt securities 1,817,009 21,958 5,909 1,833,057 Foreign corporate bonds and other debt securities (2) 816,421 1,713 214 817,921 Total 17,712,059 39,718 38,442 17,713,335 Held-to-maturity Debt securities: Japanese government bonds 519,397 208 7,585 512,020 Agency mortgage-backed securities (3) 3,528,150 9,213 186,460 3,350,904 Total 4,047,547 9,421 194,044 3,862,924 Notes: (1) Agency mortgage-backed securities presented in this line consist of Japanese and Foreign agency mortgage-backed securities, of which the fair values were ¥522,166 million and ¥31 million, respectively, at March 31, 2023, and ¥476,947 million and ¥26 million, respectively, at March 31, 2024. All Japanese agency mortgage-backed securities are issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise. Foreign agency mortgage-backed securities primarily consist of Government National Mortgage Association (“Ginnie Mae”) securities, which are guaranteed by the United States government. (2) Other debt securities presented in this line primarily consist of Foreign negotiable certificates of deposit (“NCDs”) and asset-backed securities (“ABS”), of which the total fair values were ¥330,365 million at March 31, 2023, and ¥209,956 million at March 31, 2024. (3) All Agency mortgage-backed securities presented in this line are Ginnie Mae securities. (4) Amortized cost, net of the allowance for credit losses, of which the amounts related to available-for-sale (5) Accrued interest receivables are excluded from amortized cost, of which the amount were ¥5,637 million at March 31, 2023, and ¥15,708 million at March 31, 2024 and included in Accrued income.
Amortized Cost and Fair Value of Available-for-Sale and Held-to-Maturity Securities by Contractual Maturity	The amortized cost, net of allowance for credit losses, and fair value of available-for-sale held-to-maturity Amortized cost Due in one year or less Due after one year through five years Due after five years through ten years Due after ten years Total (in millions of yen) Available-for-sale Debt securities: Japanese government bonds 10,565,041 11,922 391,249 —  10,968,212 Japanese local government bonds 72,554 220,432 288,731 9,501 591,218 U.S. Treasury bonds and federal agency securities 147,186 —  —  —  147,186 Other foreign government bonds 1,513,211 526,826 3,293 1,281 2,044,611 Agency mortgage-backed securities —  —  912 494,145 495,057 Residential mortgage-backed securities —  —  —  32,120 32,120 Commercial mortgage-backed securities 12,480 545,950 241,794 —  800,224 Japanese corporate bonds and other debt securities 270,114 1,011,897 205,192 329,806 1,817,009 Foreign corporate bonds and other debt securities 463,244 240,076 92,781 20,320 816,421 Total 13,043,830 2,557,103 1,223,953 887,173 17,712,059 Held-to-maturity Debt securities: Japanese government bonds 100,005 179,850 239,542 —  519,397 Agency mortgage-backed securities —  —  —  3,528,150 3,528,150 Total 100,005 179,850 239,542 3,528,150 4,047,547 Fair value Due in one year or less Due after one year through five years Due after five years through ten years Due after ten years Total (in millions of yen) Available-for-sale Debt securities: Japanese government bonds 10,562,258 11,912 400,223 —  10,974,393 Japanese local government bonds 72,521 219,353 282,856 9,009 583,739 U.S. Treasury bonds and federal agency securities 147,052 —  —  —  147,052 Other foreign government bonds 1,512,511 527,510 3,294 1,281 2,044,595 Agency mortgage-backed securities —  —  904 476,068 476,972 Residential mortgage-backed securities —  —  —  31,383 31,383 Commercial mortgage-backed securities 12,485 547,001 244,736 —  804,222 Japanese corporate bonds and other debt securities 270,031 1,009,579 203,358 350,089 1,833,057 Foreign corporate bonds and other debt securities 463,311 240,935 92,929 20,746 817,921 Total 13,040,169 2,556,290 1,228,299 888,577 17,713,335 Held-to-maturity Debt securities: Japanese government bonds 100,213 178,440 233,367 —  512,020 Agency mortgage-backed securities —  —  —  3,350,904 3,350,904 Total 100,213 178,440 233,367 3,350,904 3,862,924
Gross Unrealized Losses and Fair Value of Available-for-Sale and Held-to-Maturity Securities, Aggregated by Length of Time that Individual Securities Have Been in a Continuous Unrealized Loss Position	The following table shows the gross unrealized losses, net of allowance for credit losses, and fair value of available-for-sale Less than 12 months 12 months or more Total Fair value Gross unrealized losses Fair value Gross unrealized losses Fair value Gross unrealized losses (in millions of yen) 2023 Available-for-sale Debt securities: Japanese government bonds 3,706,134 11,369 1,419,222 26,127 5,125,356 37,496 Japanese local government bonds 146,484 1,596 322,224 4,032 468,708 5,628 U.S. Treasury bonds and federal agency securities 65,288 765 293,149 6,524 358,437 7,289 Other foreign government bonds 475,493 674 250,130 1,587 725,623 2,261 Agency mortgage-backed securities (Note) 142,776 2,361 238,858 8,946 381,634 11,307 Residential mortgage-backed securities 16,230 265 22,017 601 38,247 866 Commercial mortgage-backed securities. 105,346 304 43,653 147 148,999 451 Japanese corporate bonds and other debt securities 1,177,725 3,775 635,289 763 1,813,014 4,538 Foreign corporate bonds and other debt securities 434,339 1,279 68,959 302 503,298 1,581 Total 6,269,815 22,388 3,293,501 49,029 9,563,316 71,417 2024 Available-for-sale Debt securities: Japanese government bonds 9,019,722 2,448 675,435 508 9,695,157 2,956 Japanese local government bonds 108,071 369 456,471 7,205 564,542 7,574 U.S. Treasury bonds and federal agency securities 113,185 252 —  —  113,185 252 Other foreign government bonds 865,375 1,196 107,238 559 972,613 1,755 Agency mortgage-backed securities (Note) 130,779 1,125 307,777 17,100 438,556 18,225 Residential mortgage-backed securities 645 —  25,220 766 25,865 767 Commercial mortgage-backed securities. 18,594 214 138,724 576 157,318 789 Japanese corporate bonds and other debt securities 314,933 893 1,217,858 5,016 1,532,791 5,909 Foreign corporate bonds and other debt securities 203,248 166 24,902 48 228,150 214 Total 10,774,551 6,663 2,953,626 31,779 13,728,177 38,442 Note: Agency mortgage-backed securities presented in this line consist of Japanese agency mortgage-backed securities, of which the fair values were ¥381,634 million at March 31, 2023, and ¥438,556 million at March 31, 2024. All Japanese agency mortgage-backed securities are issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise.
Realized Gains and Losses on Sales of Available-for-Sale Securities	The following table shows the realized gains and losses on sales of available-for-sale 2022 2023 2024 (in millions of yen) Gross realized gains 12,540 22,962 34,287 Gross realized losses (40,077 ) (23,593 ) (51,384 ) Net realized gains (losses) on sales of available-for-sale (27,537 ) (631 ) (17,097 )
Summary of Details of Net Gains and Losses on Equity Securities	The following table shows the details of the net gains and losses on Equity securities for the fiscal years ended March 31, 2022, 2023 and 2024: 2022 2023 2024 (in millions of yen) Net gains (losses) recognized during the period on equity securities (60,563 ) 135,601 1,010,288 Less: Net gains (losses) recognized during the period on equity securities sold during the period 17,000 29,561 235,564 Unrealized gains (losses) recognized during the reporting period on equity securities still held at the reporting period (77,563 ) 106,040   774,724
Summary of Downward Adjustments and Impairments and Upward Adjustments	The following table shows carrying amounts of equity securities without readily determinable fair values, for which the measurement alternative is used, and cumulative amounts due to downward adjustments and impairments and upward adjustments, at March 31, 2022, 2023 and 2024: 2022 2023 2024 (in millions of yen) Carrying amounts at the end of the period 207,407   207,743   357,938 Downward adjustments and impairments 6,519 5,345 11,002 Upward adjustments 11,623 13,015 13,764
Summary of Equity Securities Without Readily Determinable Fair Values	The following table shows amounts recognized in earnings during the period due to downward adjustments and impairments and upward adjustments for equity securities without readily determinable fair values. 2022 2023 2024 (in millions of yen) Downward adjustments and impairments   2,626     1,291     7,296 Upward adjustments 2,459 1,459 825
Summary of Composition of Other Investments	The following table summarizes the composition of Other investments at March 31, 2023 and 2024: 2023 2024 (in millions of yen) Equity method investments 598,772 799,527 Investments held by consolidated investment companies and other 68,429 84,969 Total 667,201 884,496

Loans (Tables)

Loans (Tables)	12 Months Ended
	Mar. 31, 2024
Credit Quality Information of Loans Based on MHFG Group's Internal Rating System	The table below presents credit quality information of loans based on the MHFG Group’s internal rating system at March 31, 2023 and 2024: Term loans by origination year 2022 2021 2020 2019 2018 Prior to 2018 Revolving Loans (2) Total (in billions of yen) 2023 Domestic: Corporate: Large companies: Normal obligors     12,277      5,993      5,384      3,994      3,065      3,670      7,517     41,900 Watch obligors excluding special attention obligors 109 46 50 58 59 33 130 485 Nonaccrual loans 153 35 61 134 99 159 339 980 Small and medium-sized Normal obligors 551 301 285 248 221 571 531 2,708 Watch obligors excluding special attention obligors 45 16 26 16 18 28 20 169 Nonaccrual loans 26 7 16 9 8 27 29 122 Retail (1) Housing Loan: Normal obligors 711 570 476 468 478 4,723 —  7,426 Watch obligors excluding special attention obligors 1 2 1 2 1 35 —  42 Nonaccrual loans 8 2 2 1 1 25 —  39 Others: Normal obligors 184 87 226 80 64 297 484 1,422 Watch obligors excluding special attention obligors 22 6 21 5 4 5 8 71 Nonaccrual loans 9 4 6 2 4 20 10 55 Sovereign: Normal obligors 1,217 54 90 91 75 328 1 1,856 Watch obligors excluding special attention obligors 8 2 —  —  —  —  —  10 Nonaccrual loans —  —  —  —  —  —  —  —  Banks and other financial institutions: Normal obligors 107 17 23 134 155 114 95 645 Watch obligors excluding special attention obligors —  —  —  —  —  —  —  —  Nonaccrual loans —  —  —  —  —  —  —  —  Total domestic 15,428 7,142 6,667 5,242 4,252 10,035 9,164 57,930 Foreign: Corporate (3) Normal obligors 15,317 3,891 2,142 1,954 1,024 1,312 6,731 32,371 Watch obligors excluding special attention obligors 228 101 192 72 43 50 58 744 Nonaccrual loans 31 19 13 18 11 32 11 135 Retail: Normal obligors 2 1 1 1 1 3 —  9 Watch obligors excluding special attention obligors —  —  —  —  —  —  —  —  Nonaccrual loans —  —  —  —  —  —  —  —  Sovereign: Normal obligors 160 188 7 32 5 2 83 477 Watch obligors excluding special attention obligors —  —  —  —  —  —  —  —  Nonaccrual loans —  —  —  1 —  —  —  1 Banks and other financial institutions: Normal obligors 1,536 265 169 91 19 4 404 2,488 Watch obligors excluding special attention obligors 8 4 4 5 —  —  —  21 Nonaccrual loans —  —  —  —  —  —  —  —  Total foreign 17,282 4,469 2,528 2,174 1,103 1,403 7,287 36,246 Total 32,710 11,611 9,195 7,416 5,355 11,438 16,451 94,176 Term loans by origination year 2023 2022 2021 2020 2019 Prior to 2019 Revolving Loans (2) Total (in billions of yen) 2024 Domestic: Corporate: Large companies: Normal obligors     13,870      5,879      4,505      4,328      2,832      4,979      7,847     44,241 Watch obligors excluding special attention obligors 186 42 37 43 184 49 172 713 Nonaccrual loans 157 65 26 61 134 167 356 967 Small and medium-sized Normal obligors 430 251 195 150 151 533 494 2,204 Watch obligors excluding special attention obligors 35 15 10 12 15 30 19 135 Nonaccrual loans 8 7 7 8 8 33 26 97 Retail (1) Housing Loan: Normal obligors 350 391 431 342 360 5,224 —  7,098 Watch obligors excluding special attention obligors —  —  —  —  —  36 —  37 Nonaccrual loans —  —  —  —  1 33 —  35 Others: Normal obligors 211 71 54 100 48 337 470 1,291 Watch obligors excluding special attention obligors 23 6 5 10 3 7 8 62 Nonaccrual loans 5 2 3 6 2 22 9 49 Sovereign: Normal obligors 1,858 47 48 92 66 321 3 2,436 Watch obligors excluding special attention obligors 8 2 1 —  —  —  —  12 Nonaccrual loans —  —  —  —  —  —  —  —  Banks and other financial institutions: Normal obligors 120 103 262 2 107 110 527 1,231 Watch obligors excluding special attention obligors —  —  —  —  —  —  —  —  Nonaccrual loans —  —  —  —  —  —  —  —  Total domestic 17,261 6,882 5,585 5,155 3,911 11,883 9,932 60,608 Foreign: Corporate (3) Normal obligors 14,106 5,488 2,589 1,028 1,128 1,028 7,706 33,073 Watch obligors excluding special attention obligors 243 83 35 161 22 57 105 705 Nonaccrual loans 60 27 2 5 2 19 13 127 Retail: Normal obligors 2 1 1 1 1 3 —  10 Watch obligors excluding special attention obligors —  —  —  —  —  —  —  —  Nonaccrual loans —  —  —  —  —  —  —  —  Sovereign: Normal obligors 319 215 117 2 4 —  29 686 Watch obligors excluding special attention obligors —  —  —  —  —  —  —  —  Nonaccrual loans —  —  —  —  —  —  —  —  Banks and other financial institutions: Normal obligors 1,674 874 193 21 2 7 448 3,219 Watch obligors excluding special attention obligors —  6 4 —  6 —  —  16 Nonaccrual loans —  —  —  —  —  —  —  —  Total foreign 16,403 6,694 2,941 1,219 1,164 1,114 8,302 37,837 Total 33,665 13,575 8,525 6,374 5,075 12,997 18,233 98,445 Notes: (1) The primary component of the retail portfolio segment is housing loans to individuals which obligor category is classified based on past due status. The trigger to reclassify obligors from normal obligors to watch obligors excluding special attention obligors is when the past due status is more than 30 days. (2) There were no significant revolving line of credit arrangements that converted to term loans during the fiscal year ended March 31, 2023 and 2024. (3) Corporate of foreign included ¥184 billion and ¥176 billion of lease receivables that were receivables arising from direct financing leasing at March 31, 2023 and 2024, respectively.
Allowance For Credit Losses Write off On Financing Receivables	The table below presents gross charge-offs recognized for the fiscal year ended March 31, 2024: March 31, 2024 2023 2022 2021 2020 2019 Prior to 2019 Revolving Loans Total (in billions of yen) Domestic: Corporate: Large companies 5 13 3     —        2 1 2 27 Small and medium-sized 1 2 —  —  —  —  2 5 Retail: Housing Loan —  —  —  —  —  2 —  2 Others 1 1 —  —  —  1 —  3 Total domestic 6 16 3 —  2 4 4 37 Foreign: Total foreign (Note) —  1 1 2 —  6 —  10 Total 7 18 3 2 2 10 4 46 Note: The majority of total foreign consist of corporate.
Impaired Loans Information	The table below presents nonaccrual loans information at March 31, 2023 and 2024: Amortized cost (1) Interest income recognized (2) Nonaccrual loans with an allowance Nonaccrual loans without an allowance Total nonaccrual loans (in billions of yen) 2023 Domestic: Corporate: Large companies 961 19 980 16 Small and medium-sized 103 19 122 1 Retail: Housing Loan 22 17 39 1 Others 37 18 55 1 Total domestic 1,123 73 1,196 19 Foreign: Total foreign (3) 132 4 136 4 Total 1,255 77 1,332 23 2024 Domestic: Corporate: Large companies 950 17 967 13 Small and medium-sized 86 12 97 1 Retail: Housing Loan 20 15 35 1 Others 31 18 49 1 Total domestic 1,088 61 1,149 16 Foreign: Total foreign (3) 124 3 127 4 Total 1,212 64 1,276 20 Notes: (1) Amounts represent the outstanding balances of nonaccrual loans. The MHFG Group’s policy for placing loans in nonaccrual status is consistent with the Group’s definition of nonaccrual loans. (2) Amounts represent the amount of interest income on nonaccrual loans recognized on a cash basis and included in Interest income on loans in the consolidated statements of income. (3) The majority of total foreign consist of corporate.
Troubled Debt Restructurings Entered Modified Periods by Type of Concession Granted	The MHFG Group grants certain modifications of loans to borrowers experiencing financial difficulty. The following table presents modified loans that were determined to be TDRs during the fiscal year ended March 31, 2023: Loan forgiveness or debt to equity swaps Interest rate reduction and/or postponement of principal and/or interest Recorded investment (1) Charge-offs (in billions of yen) 2023 Domestic: Corporate: Large companies —  141 595 Small and medium-sized —  —  106 Retail: Housing Loan —  —  5 Others —  —  19 Total domestic —  141 725 Foreign: Total foreign (2) —  —  66 Total    —       141       791 Notes: (1) Amounts represent the book values of loans immediately after the restructurings. (2) The majority of total foreign consist of corporate.
Troubled Debt Restructurings On Financing Receivables	The following table presents loan modifications to borrowers experiencing financial difficulty by type of modification during the fiscal year ended March 31, 2024: Term (2) Interest (2) Term Principal Other Total (3)(4) (in billions of yen) 2024 Domestic: Corporate: Large companies     227      —        4       —        6     237 Small and medium-sized 34 —  2 —  —  35 Retail: Housing Loan —  —  —  —  —  —  Others 4 —  —  —  —  5 Total domestic 265 —  6 —  6 278 Foreign: Total foreign (1) 15 5 1 —  —  20 Total 280 5 6 —  6 298 Notes: (1) The majority of total foreign consist of corporate. (2) The financial effects of loan modifications, which were largely in the form of term extensions and interest rate reductions, included extending the weighted-average life of the loans by 12.1 months, and reducing the weighted-average contractual interest rate by 0.6% for the fiscal year ended March 31, 2024. (3) Commitments to lend to borrowers experiencing financial difficulty that were granted modifications were immaterial at March 31, 2024. (4) The allowance for credit losses on loans is based on macroeconomic-sensitive models that rely on historical performance and macroeconomic scenarios to forecast expected credit losses. Modifications of loans impact expected credit losses by affecting the likelihood of default.
Delinquent Status of Modified Loans to Borrowers Experiencing Financial Difficulty	The following table presents the delinquent status of modified loans to borrowers experiencing financial difficulty, including loans that were modified during the fiscal year ended March 31, 2024: 30-59 days 60-89 days 90 days or Total past Current Total (in billions of yen) 2024 Domestic: Corporate: Large companies —  —  4 4 234 237 Small and medium-sized      —       —      —      —       35      35 Retail: Housing Loan —  —  —  —  —  —  Others —  —  —  —  5 5 Total domestic —  —  4 5 273 278 Foreign: Total foreign (Note) —  —  —  —  20 20 Total —  —  4 5 293 298 Note: The majority of total foreign consist of corporate.
Payment Defaults Occurred During Periods with Respect to Loans Modified as Troubled Debt Restructurings within Previous Twelve Months	The following table presents payment defaults which occurred during the fiscal year ended March 31, 2023 with respect to the loans modified as TDRs within the previous twelve months: Recorded investment 2023 (in billions of yen) Domestic: Corporate: Large companies 95 Small and medium-sized 1 Retail: Housing Loan 1 Others 1 Total domestic 98 Foreign: Total foreign 10 Total     108
Age Analysis of Past Due Loans	The table below presents an analysis of the age of the amortized cost basis in loans that are past due at March 31, 2023 and 2024: 30-59 days past due 60-89 days past due 90 days or more past due Total past due Current Total (in billions of yen) 2023 Domestic: Corporate: Large companies —  3 28 31 43,334 43,365 Small and medium-sized —  —  9 9 2,990 2,999 Retail: Housing Loan 14 8 13 35 7,472 7,507 Others 4 1 10 15 1,533 1,548 Sovereign —  —  —  —  1,866 1,866 Banks and other financial institutions —  —  —  —  645 645 Total domestic 18 12 60 90 57,840 57,930 Foreign: Total foreign (Note) —  —  23 23 36,223 36,246 Total 18 12 83 113 94,063 94,176 2024 Domestic: Corporate: Large companies 1 —  35 37 45,884 45,921 Small and medium-sized —  1 5 6 2,431 2,436 Retail: Housing Loan 12 7 12 31 7,139 7,170 Others 5 1 10 16 1,387 1,403 Sovereign —  —  —  —  2,447 2,447 Banks and other financial institutions —  —  —  —  1,231 1,231 Total domestic 18 9 62 89 60,519 60,608 Foreign: Total foreign (Note) —  —  20 20 37,817 37,837 Total 18 9 82 109 98,335 98,445 Note: The majority of total foreign consist of corporate.

Allowance for Credit Losses o_2

Allowance for Credit Losses on Loans (Tables)	12 Months Ended
	Mar. 31, 2024
Changes in Allowance for Loan Losses, Allowance for Loan Losses and Loans Outstanding Disaggregated on Basis of Impairment Method, by Portfolio Segment	Changes in Allowance for credit losses on loans by portfolio segment for the fiscal years ended March 31, 2022, 2023 and 2024 are shown below: Domestic Corporate Retail Sovereign Banks and other financial institutions Foreign (2) Total (in millions of yen) 2022 Balance at beginning of fiscal year 481,420 83,171 68 623 85,567 650,849 Provision (credit) for credit losses on loans 144,998 (6,895 ) (6 ) (227 ) 49,729 187,599 Charge-offs (32,530 ) (4,166 ) —  —  (23,144 ) (59,840 ) Recoveries 7,618 1,304 —  —  9,832 18,754 Net charge-offs (24,912 ) (2,862 ) —  —  (13,312 ) (41,086 ) Others (1) —  —  —  42 12,413 12,455 Balance at end of fiscal year 601,506 73,414 62 438 134,397 809,817 2023 Balance at beginning of fiscal year 601,506 73,414   62 438 134,397 809,817 Provision (credit) for credit losses on loans 51,551 (5,413 ) (9 )   432 44,287 90,848 Charge-offs (3) (153,014 ) (5,664 ) —  —  (68,772 ) (227,450 ) Recoveries 5,858 1,204 —  —  3,414 10,476 Net charge-offs (147,156 ) (4,460 ) —  —  (65,358 ) (216,974 ) Others (1) —  —  —  —  17,268 17,268 Balance at end of fiscal year 505,901 63,541 53 870 130,594 700,959 2024 Balance at beginning of fiscal year 505,901 63,541 53 870 130,594 700,959 Provision (credit) for credit losses on loans 83,702 (4,208 ) (9 ) (597 ) (26,061 ) 52,827 Charge-offs (3) (31,936 ) (4,882 ) —  —  (9,505 ) (46,323 ) Recoveries 6,049 1,338 —  —  4,561 11,948 Net charge-offs (25,887 ) (3,544 ) —  —  (4,945 ) (34,376 ) Others (1) —  —  —  —  30,660 30,660 Balance at end of fiscal year 563,716 55,790 44 273 130,249 750,071 Notes: (1) Others includes primarily foreign exchange translation. (2) The majority of total foreign consist of corporate. (3) Charge-offs decreased from ¥227,450 million for the fiscal year ended March 31, 2023 to ¥46,323 million for the fiscal year ended March 31, 2024. The decrease was due mainly to a charge-off related to a debt waiver to a domestic corporate borrower which was recognized in the fiscal year ended March 31, 2023.

Premises and equipment (Tables)

Premises and equipment (Tables)	12 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Summary of Premises and Equipment	Premises and equipment at March 31, 2023 and 2024 consist of the following:   2023     2024   (in millions of yen) Land 577,755 577,026 Buildings 703,655 684,476 Equipment and furniture 378,015 393,379 Leasehold improvements 204,835 217,762 Construction in progress 44,393 47,787 Software 1,366,445 1,452,645 Total 3,275,098 3,373,076 Less: Accumulated depreciation and amortization 1,621,210 1,658,590 Premises and equipment—net 1,653,888 1,714,485

Goodwill and intangible assets

Goodwill and intangible assets (Tables)	12 Months Ended
	Mar. 31, 2024
Changes in Goodwill	The changes in Goodwill during the fiscal years ended March 31, 2022, 2023 and 2024 are as follows:   2022     2023     2024   (in millions of yen) Balance at beginning of fiscal year 92,695 92,695 92,928 Goodwill acquired (1) —  233 66,980 Foreign exchange translation —  —  4,550 Balance at end of fiscal year 92,695 92,928 164,458 Gross amount of goodwill (2) 161,993 163,209 235,563 Accumulated impairment losses 69,298 70,281 71,105 Notes: (1) For the fiscal year ended March 31, 2024, Goodwill acquired is entirely related to the acquisition of Greenhill & Co., Inc. (2) Goodwill is recorded at a designated reporting unit level for the purpose of assessing impairment. Goodwill is not allocated to the reportable segments in Note 30 “Business segment information.”
Gross Carrying Amount, Accumulated Amortization and Net Carrying Amount of Intangible Assets	The table below presents the gross carrying amount, accumulated amortization and net carrying amount of intangible assets at March 31, 2023 and 2024: 2023 2024 Gross carrying amount Accumulated amortization Net carrying amount Gross carrying amount Accumulated amortization Net carrying amount (in millions of yen) Intangible assets subject to amortization: Customer relationships (Note) 130,124 94,777 35,347 135,866 102,231 33,636 Other 2,883 1,408 1,475 7,696 3,641 4,055 Total 133,007 96,185 36,822 143,562 105,871 37,690 Intangible assets not subject to amortization: Total 7,859 —  7,859 7,293 —  7,293 Total 140,866 96,185 44,681 150,855 105,871 44,984 Note: Customer relationships were mainly acquired in connection with the merger of MHSC and Shinko on May 7, 2009 and the integration among asset management companies on October 1, 2016. See Note 1 “Basis of presentation and summary of significant accounting policies” for further information.
Estimated Aggregate Amortization Expense in Respect of Intangible Assets	The table below presents the estimated aggregate amortization expense in respect of intangible assets for the next five years: (in millions of yen) Fiscal year ending March 31: 2025 8,825 2026 7,211 2027 6,492 2028 3,526 2029 3,098

Pledged assets and collateral (

Pledged assets and collateral (Tables)	12 Months Ended
	Mar. 31, 2024
Amounts Pledged as Collateral for Borrowings and for Other Purposes	The following amounts, by balance sheet classification, have been pledged as collateral for borrowings and for other purposes at March 31, 2023 and 2024:   2023     2024   (in billions of yen) Interest-bearing deposits in other banks 92 94 Trading account assets 7,830 12,331 Investments 12,452 15,081 Loans 8,715 8,699 Other assets 2,059 2,699 Total 31,148 38,904
Associated Liabilities Collateralized by Pledged Assets	The associated liabilities collateralized by the above assets at March 31, 2023 and 2024 are summarized below:   2023     2024   (in billions of yen) Deposits 988 217 Payables under repurchase agreements 10,542 17,553 Payables under securities lending transactions 721 689 Other short-term borrowings 1,003 1,803 Long-term debt 2,173 2,490 Total 15,427 22,752

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Mar. 31, 2024
Balance and Remaining Maturities of Time Deposits and Certificates of Deposit Issued by Domestic and Foreign Offices	The balance and remaining maturities of time deposits and certificates of deposit issued by domestic and foreign offices at March 31, 2024 are shown in the following table: Time deposits Certificates of Total (in millions of yen) Domestic offices: Due in one year or less 21,154,572 2,339,785 23,494,357 Due after one year through two years 1,121,763 121,500 1,243,263 Due after two years through three years 917,388 —  917,388 Due after three years through four years 273,448 —  273,448 Due after four years through five years 316,649 —  316,649 Due after five years 300,193 —  300,193 Total 24,084,013 2,461,285 26,545,298 Foreign offices: Due in one year or less 24,366,453 8,783,902 33,150,355 Due after one year through two years 34,381 98,670 133,051 Due after two years through three years 14,995 172,673 187,667 Due after three years through four years 211 74,003 74,214 Due after four years through five years 1 —  1 Due after five years —  —  —  Total 24,416,041 9,129,247 33,545,288 Total 48,500,053 11,590,532 60,090,586
Estimated amounts of uninsured time deposits and certificates of deposit issued by domestic and foreign offices	The aggregate estimated amounts of time deposits and certificates of deposit that meet or exceed insurance limit issued by domestic and foreign offices at March 31, 2023 and 2024 are shown in the following table:   2023     2024   (in billions of yen) Domestic offices: Time deposits 13,977 17,031 Certificates of deposit 6,232 2,461 Total 20,209 19,492 Foreign offices: Time deposits 22,503 24,416 Certificates of deposit 7,556 9,129 Total 30,059 33,545

Short-term borrowings and lon_2

Short-term borrowings and long-term debt (Tables)	12 Months Ended
	Mar. 31, 2024
Details of Other Short-Term Borrowings	Details of Other short-term borrowings at March 31, 2023 and 2024 are as follows:   2023     2024   (in millions of yen) Short-term notes issued by consolidated VIEs of asset-backed commercial paper programs (1) 41,142 89,736 Commercial paper and short-term notes issued by MHFG’s subsidiaries (1) (2) 2,218,111 1,641,988 Borrowings from the Bank of Japan 876,036 1,588,529 Other 262,040 324,659 Total  3,397,329  3,644,912 Notes: (1) Short-term notes are issued under the laws of Japan in the form of commercial paper. (2) The amounts of commercial paper and short-term notes issued by MHFG’s subsidiaries were ¥1,782,111 million and ¥436,000 million, respectively, at March 31, 2023, and ¥1,165,988 million and ¥476,000 million, respectively, at March 31, 2024.
Long-Term Debt with Original Maturities of More than One Year	Long-term debt with original maturities of more than one year at March 31, 2023 and 2024 is comprised of the following:   2023     2024   (in millions of yen) Obligations under finance 6,863 21,185 Loan participation borrowings 245,176 258,201 Senior borrowings and bonds 11,245,475 12,556,710 Subordinated borrowings and bonds 3,395,509 3,441,235 Total 14,893,023 16,277,331
Interest Rates and Maturities of Senior Borrowings and Bonds, and Subordinated Borrowings and Bonds	The following table presents the interest rates and and Interest rates (1) Maturities (2)   2023     2024   (%) (in millions of yen) Senior borrowings and bonds: fixed rate denominated in Japanese yen 0.00-6.20 Apr.2024 Jun.2051 2,819,085 3,313,535 fixed rate denominated in U.S. dollars 0.00-6.00 Apr.2024 Mar.2048 3,692,271 4,333,084 fixed rate denominated in other currencies 0.00-6.02 Apr.2024 May.2041 1,948,714 2,361,302 floating rate denominated in Japanese yen 0.00-25.00 Apr.2024 Sep.2081 569,173 509,799 floating rate denominated in U.S. dollars 0.10-17.20 Apr.2024 Apr.2068 2,058,714 1,993,666 floating rate denominated in other currencies 0.00-8.00 Apr.2024 Sep.2041 157,518 45,325 Total 11,245,475 12,556,710 Subordinated borrowings and bonds: fixed rate denominated in Japanese yen 0.39-4.26 Jun.2024 2,961,504 3,176,285 fixed rate denominated in U.S. dollars 2.56-4.35 Oct.2025 Sep.2031 434,005 264,950 Total 3,395,509 3,441,235 Total 14,640,984 15,997,945 Notes: (1) The interest rates disclosed reflect the range of contractual rates in effect at March 31, 2024. (2) Maturity information disclosed is the range of maturities at March 31, 2024. (3) None of the long-term debt issuances above are convertible to common stock. (4) Certain debt agreements permit the MHFG Group to redeem the related debt, in whole or in part, prior to maturity at the MHFG Group’s option on terms specified in the respective agreements.
Contractual Maturities of Long-Term Debt	The following is a summary of contractual maturities of long-term debt subsequent to March 31, 2024: (in millions of yen) Fiscal year ending March 31: 2025 3,499,569 2026 926,755 2027 1,692,064 2028 1,363,547 2029 986,587 2030 and thereafter 7,808,809 Total 16,277,331

Other assets and liabilities (T

Other assets and liabilities (Tables)	12 Months Ended
	Mar. 31, 2024
Details of Other Assets and Liabilities	The following table sets forth the details of other assets and liabilities at March 31, 2023 and 2024: 2023 2024 (in millions of yen) Other assets: Accounts receivable: Receivables from brokers, dealers and customers for securities transactions 4,469,286 2,278,334 Other 468,344 571,349 Collateral pledged: Collateral pledged for derivative transactions 988,881 1,406,369 Margins provided for futures contracts 183,747 264,473 Other 890,350 1,014,478 Prepaid pension cost 768,998 763,254 Right-of-use 549,668 522,936 Security deposits 83,343 83,204 Loans held for sale 228,995 103,592 Other (1) 1,069,348 1,272,162 Total 9,700,960 8,280,151 Other liabilities: Accounts payable: Payables to brokers, dealers and customers for securities transactions 1,799,116 1,049,094 Other 527,493 639,106 Guaranteed trust principal (2) 817,448 785,292 Lease liabilities 571,087 548,699 Collateral accepted: Collateral accepted for derivative transactions 1,008,083 1,382,985 Margins accepted for futures contracts 81,925 25,405 Unearned income 112,077 101,150 Other 1,399,466 1,737,267 Total 6,316,695 6,268,999 Notes: (1) The MHFG Group included premises and equipment classified as held for sale in Other. (2) Guaranteed trust principal, included in All other liabilities in the disclosure about consolidated VIEs in the accompanying balance sheets, is a liability of certain consolidated trust arrangements that meet the definition of a VIE for which the MHFG Group provides guarantees for the repayment of principal. See Note 23 “Variable interest entities and securitizations” for further discussion of the guaranteed principal money trusts.

Preferred stock (Tables)

Preferred stock (Tables)	12 Months Ended
	Mar. 31, 2024
Preferred stock
Schedule of Stock by Class	The composition of preferred stock at March 31, 2022, 2023 and 2024 is as follows: 2022 2023 2024 Class of stock Authorized Issued Authorized Issued Authorized Issued (number of shares) Class XIV preferred stock 90,000,000 —  90,000,000 —  90,000,000 —  Class XV preferred stock 90,000,000 —  90,000,000 —  90,000,000 —  Class XVI preferred stock 150,000,000 —  150,000,000 —  150,000,000 —

Common stock (Tables)

Common stock (Tables)	12 Months Ended
	Mar. 31, 2024
Common Stock
Schedule of Stock by Class	The following table shows the changes in the number of issued shares of common stock during the fiscal years ended March 31, 2022, 2023 and 2024: 2022 2023 2024 (shares) Balance at beginning of fiscal year 2,539,249,894 2,539,249,894 2,539,249,894 Issuance of new shares of common stock due to exercise of stock acquisition rights —  —  —  Balance at end of fiscal year 2,539,249,894 2,539,249,894 2,539,249,894

Accumulated other comprehensi_2

Accumulated other comprehensive income (loss), net of tax (Tables)	12 Months Ended
	Mar. 31, 2024
Changes in Each Component of Accumulated Other Comprehensive Income (Loss), Net of Tax ("AOCI")	Changes in each component of AOCI for the fiscal years ended March 31, 2022, 2023 and 2024 are as follows: 2022 2023 2024 (in millions of yen) AOCI, balance at beginning of fiscal year 318,114 440,112 649,395 Net unrealized gains (losses) on available-for-sale Balance at beginning of fiscal year (8,173 ) (25,046 ) (31,084 ) Unrealized holding gains (losses) during year (35,922 ) (7,472 ) 20,972 Less: reclassification adjustments for losses (gains) included in net income 19,049 1,434 12,173 Change during year (16,873 ) (6,038 ) 33,145 Balance at end of fiscal year (25,046 ) (31,084 ) 2,061 Foreign currency translation adjustments: Balance at beginning of fiscal year (86,873 ) 94,104 227,660 Foreign currency translation adjustments during year 181,722 133,556 258,887 Less: reclassification adjustments for losses (gains) included in net income (745 ) —  (18,682 ) Change during year 180,977 133,556 240,204 Balance at end of fiscal year 94,104 227,660 467,864 Defined benefit plan adjustments: Balance at beginning of fiscal year 397,153 355,355 423,677 Unrealized gains (losses) during year (22,825 ) 86,326 97,847 Less: reclassification adjustments for losses (gains) included in net income (18,973 ) (18,004 ) (21,861 ) Change during year (41,798 ) 68,322 75,986 Balance at end of fiscal year 355,355 423,677 499,663 Own credit risk adjustments: Balance at beginning of fiscal year 16,007 15,699 29,142 Unrealized gains (losses) during year (858 ) 12,688 (15,403 ) Less: reclassification adjustments for losses (gains) included in net income 550 755 1,251 Change during year (308 ) 13,443 (14,152 ) Balance at end of fiscal year 15,699 29,142 14,990 Total other comprehensive income (loss), net of tax attributable to MHFG shareholders 121,998 209,283 335,184 AOCI, balance at end of fiscal year 440,112 649,395 984,578
Amounts Reclassified Out of Accumulated Other Comprehensive Income into Net Income	The following table shows the amounts reclassified out of AOCI into net income during the fiscal year ended March 31, 2024: Before tax (1) Tax effect (2) Net of tax before allocation to noncontrolling interests Net of tax attributable to noncontrolling interests (2) Net of tax attributable to MHFG shareholders (in millions of yen) Amounts reclassified out of AOCI Affected line items in Net unrealized gains (losses) on available-for-sale (17,325 ) 5,151 (12,173 ) —  (12,173 ) Investment gains Foreign currency t 18,682 —  18,682 —  18,682 Foreign exchange Defined benefit plan 31,617 (9,759 ) 21,858 3 21,861 Salaries and Own credit risk (1,804 ) 552 (1,251 ) —  (1,251 ) Other noninterest Total 31,171 (4,056 ) 27,115 3 27,118 Notes: (1) The financial statement line item in which the amounts in the before tax column are reported in the consolidated statements of income is listed to the right of the table. (2) The financial statement line items in which the amounts in the tax effect and the net of tax attributable to noncontrolling interest columns are reported in the consolidated statements of income are Income tax expense (benefit) and Net income (loss), respectively.

Regulatory matters (Tables)

Regulatory matters (Tables)	12 Months Ended
	Mar. 31, 2024
Capital Requirements and Regulatory Adjustments Over Transitional Period	The capital requirements and regulatory adjustments are being phased in over a transitional period as follows: March 2023 March 2024 March 2025 March 2026 Minimum Common Equity Tier 1 capital 4.5 % 4.5 % 4.5 % 4.5 % Minimum Tier 1 capital 6.0 % 6.0 % 6.0 % 6.0 % Minimum total capital 8.0 % 8.0 % 8.0 % 8.0 % Capital conservation buffer 2.5 % 2.5 % 2.5 % 2.5 % Countercyclical capital buffer (1) 0.06 % 0.09 % 0.09 % 0.09 % Additional loss absorbency requirements for G-SIBs D-SIBs (2) 1.0 % 1.0 % 1.0 % 1.0 % Minimum Leverage Ratio (3) 3.5 % 3.5 % 3.7 % 3.7 % Notes: (1) Figures assume that the countercyclical capital buffer will continue to be 0.09% after March 2024. (2) Figures assume that the additional loss absorbency requirements applied to the Group as a G-SIB D-SIB (3) The ratios disclosed above include a leverage ratio buffer required to be met at 50% of the additional loss absorbency requirements applied to the Group as a G-SIB
Capital Adequacy Ratios of MHFG, MHBK, and MHTB Calculated in Accordance with Japanese GAAP and Guidelines Established by Financial Services Agency	Capital adequacy ratios and leverage ratios of MHFG, MHBK, and MHTB as of March 31, 2023 and 2024 calculated in accordance with Japanese GAAP and the guidelines established by the Financial Services Agency are set forth in the following table: 2023 2024   Amount     Ratio     Amount     Ratio   (in billions of yen, except percentages) Consolidated: MHFG: Common Equity Tier 1 capital: Required (1) 5,676 8.06 5,883 8.09 Actual 8,315 11.80 9,259 12.73 Tier 1 capital: Required (1) 6,733 9.56 6,973 9.59 Actual 9,803 13.91 10,801 14.85 Total risk-based capital: Required (1) 8,142 11.56 8,428 11.59 Actual 11,306 16.05 12,314 16.93 Leverage Ratio (2) Required (3) 7,680 3.50 8,028 3.50 Actual 9,803 4.46 10,801 4.70 MHBK: Common Equity Tier 1 capital: Required 2,941 4.50 2,968 4.50 Actual 6,873 10.51 7,431 11.26 2023 2024   Amount     Ratio     Amount     Ratio   (in billions of yen, except percentages) Tier 1 capital: Required 3,922 6.00 3,957 6.00 Actual 8,356 12.78 8,973 13.60 Total risk-based capital: Required 5,229 8.00 5,276 8.00 Actual 9,769 14.94 10,400 15.76 Leverage Ratio (2) Required 6,216 3.00 6,382 3.00 Actual 8,356 4.03 8,973 4.21 MHTB: Common Equity Tier 1 capital: Required 77 4.50 74 4.50 Actual 444 25.94 476 28.98 Tier 1 capital: Required 102 6.00 98 6.00 Actual 444 25.94 476 28.98 Total risk-based capital: Required 137 8.00 131 8.00 Actual 444 25.95 476 28.99 Leverage Ratio (2) Required 125 3.00 123 3.00 Actual 444 10.61 476 11.62 Non-consolidated: MHBK: Common Equity Tier 1 capital: Required 2,751 4.50 2,716 4.50 Actual 5,981 9.78 6,273 10.39 Tier 1 capital: Required 3,668 6.00 3,621 6.00 Actual 7,450 12.18 7,805 12.93 Total risk-based capital: Required 4,891 8.00 4,828 8.00 Actual 8,853 14.48 9,185 15.21 Leverage Ratio (2) Required 5,767 3.00 5,867 3.00 Actual 7,450 3.87 7,805 3.99 MHTB: Common Equity Tier 1 capital: Required 76 4.50 70 4.50 Actual    425 25.10 446 28.60 Tier 1 capital: Required 101 6.00 93 6.00 Actual 425 25.10 446 28.60 2023 2024   Amount     Ratio     Amount     Ratio   (in billions of yen, except percentages) Total risk-based capital: Required 135 8.00 124 8.00 Actual 425 25.11 446 28.60 Leverage Ratio (2) Required 122 3.00 118 3.00 Actual 425 10.44 446 11.31 Notes: (1) The required ratios disclosed above, at March 31, 2023 and 2024, include the capital conservation buffer of 2.5%, the countercyclical capital buffer of 0.06% and 0.09%, respectively, and the additional loss absorbency requirements for G-SIBs D-SIBs (2) The required and actual amounts disclosed above at March 31, 2023 and 2024 exclude amounts of deposits to the Bank of Japan. (3) The required ratios disclosed above, at March 31, 2023 and 2024, include a leverage ratio buffer required to be met at 50% of the additional loss absorbency requirements applied to the Group as a G-SIB

Earnings per common share (Tabl

Earnings per common share (Tables)	12 Months Ended
	Mar. 31, 2024
Computation of Basic and Diluted Earnings Per Common Share	The following table sets forth the computation of basic and diluted earnings per common share for the fiscal years ended March 31, 2022, 2023 and 2024: 2022 2023 2024 (in millions of yen) Net income (loss): Net income (loss) attributable to MHFG common shareholders (104,722 ) (14,009 ) 912,473 Effect of dilutive securities —  —  —  Net income (loss) attributable to common shareholders after assumed conversions (104,722 ) (14,009 ) 912,473 2022 2023 2024 (thousands of shares) Shares: Weighted average common shares outstanding 2,537,051 2,536,596 2,536,775 Effect of dilutive securities: Stock options and the common shares of MHFG under the stock compensation programs (Note) —  —  325 Weighted average common shares after assumed conversions 2,537,051 2,536,596 2,537,100 2022 2023 2024 (in yen) Earnings per common share: Basic net income (loss) per common share (41.28 ) (5.52 ) 359.70 Diluted net income (loss) per common share (Note) (41.28 ) (5.52 ) 359.65 Note: For the fiscal years ended March 31, 2022 and 2023, the performance-based plan under the stock compensation programs could potentially dilute earnings per common share but were not included in the computation of diluted earnings per common share due to their antidilutive effects. In addition, for the fiscal years ended March 31, 2022 and 2023, the computation of diluted earnings per common share did not assume exercise of stock options, as the effect of such exercise would be antidilutive due to net loss.

Income taxes (Tables)

Income taxes (Tables)	12 Months Ended
	Mar. 31, 2024
Components of Income Tax Expense (Benefit)	The following table presents the components of Income tax expense (benefit) for the fiscal years ended March 31, 2022, 2023 and 2024:   2022     2023     2024   (in millions of yen) Current:                   Domestic 42,401 22,015 36,237 Foreign 71,947 156,969 223,529 Total current tax expense 114,348 178,984 259,765 Deferred: Domestic (256,093 ) (146,721 ) 170,106 Foreign 728 2,879 (4,750 ) Total deferred tax expense (benefit) (255,365 ) (143,842 ) 165,355 Total income tax expense (benefit) (141,017 ) 35,142 425,120
Detailed Amounts of Tax Effects of Items Recorded Directly in Equity	The preceding table does not reflect the tax effects of items recorded directly in Equity for the fiscal years ended March 31, 2022, 2023 and 2024. The detailed amounts recorded directly in Equity are as follows:   2022     2023     2024   (in millions of yen) Net unrealized gains (losses) on available-for-sale       Unrealized gains (losses) (16,489 ) (4,276 ) 8,273 Less: reclassification adjustments 8,504 305 5,151 Total (7,985 ) (3,971 ) 13,425 Defined benefit plan adjustments: Unrealized gains (losses) (9,020 ) 37,661 42,415 Less: reclassification adjustments (7,748 ) (7,848 ) (9,759 ) Total (16,768 ) 29,813 32,655 Own credit risk adjustments: Unrealized gains (losses) 1,745 5,630 (6,590 ) Less: reclassification adjustments 271 334 552 Total 2,016 5,964 (6,038 ) Total tax effect before allocation to noncontrolling interests (22,737 ) 31,806 40,043
Reconciliation of Income Tax Expense at Effective Statutory Tax Rate to Actual Income Tax Expense	The following table shows a reconciliation of Income tax expense at the effective statutory tax rate to the actual income tax expense for the fiscal years ended March 31, 2022, 2023 and 2024: 2022 2023 2024 Effective statutory tax rate 30.62 % 30.62 % 30.62 % Income not subject to tax 4.21 (14.23 ) (0.58 ) Expenses not deductible for tax purposes (0.34 ) 1.63 0.08 Tax rate differentials of subsidiaries 3.31 (12.95 ) (0.92 ) Change in valuation allowance (6.68 ) (1) (5.95 ) (2.34 ) Change in undistributed earnings of subsidiaries (2.22 ) 8.32 0.52 Noncontrolling interest income (loss) of consolidated VIEs. (2.10 ) (15.48 ) (5.35 ) Effect of enacted change in tax rates 0.01 (0.05 ) —  Reversal of outside basis differences 50.59 (1) —  —  Foreign tax credit and payments (16.59 ) 55.14 3.80 Income excluded from taxable income of enterprise tax 2.86 (14.96 ) (1.04 ) Controlled foreign company rules (1.66 ) 2.68 0.06 Other (3.86 ) 16.04 1.34 Effective income tax rate 58.15 % 50.81 % 26.19 % Note: (1) These amounts for the fiscal year ended March 31, 2022 mainly represent the reversal of an outside basis difference related to the share buyback conducted by MHSC in response to improving the capital position and aligning to the MHFG Group’s capital policy and the related increase in the valuation allowance.
Components of Net Deferred Tax Assets	The components of net deferred tax assets at March 31, 2023 and 2024 are as follows: 2023 2024 (in millions of yen) Deferred tax assets: Allowance for credit losses 270,423 265,855 Trading securities 173,793 208,711 Lease liabilities 176,304 168,848 Derivative financial instruments 161,141 148,716 Foreign tax credit and payments (1) 54,416 124,695 Premises and equipment 53,531 46,967 Available-for-sale 13,020 —  Net operating loss carryforwards (2)(3) 168,387 149,521 Other 201,141 290,733 1,272,156 1,404,047 Valuation allowance (1)(2)(3) (198,800 ) (233,991 ) Deferred tax assets, net of valuation allowance 1,073,356 1,170,057 Deferred tax liabilities: Investments 264,147 502,589 Prepaid pension cost and accrued pension liabilities 224,173 222,408 Right-of-use 169,353 160,630 Available-for-sale securities —  404 Other 54,515 120,104 Deferred tax liabilities 712,188 1,006,135 Net deferred tax assets 361,168 163,921 Notes: (1) The amount includes ¥37,517 million and ¥99,994 million related to MHBK’s foreign tax credit carryforwards as of March 31, 2023 and 2024, respectively. The amount is fully offset by valuation allowance, and if not utilized, the amount will expire during the fiscal years ending March 31, 2026 and 2027 (2) The amount includes ¥49,393 million and ¥9,186 million related to MHSC’s net operating loss carryforwards resulting mainly from the organizational restructuring of certain foreign subsidiaries as of March 31, 2023 and 2024, respectively. The tax effect of the net operating loss carryforwards is substantially offset by ¥43,488 million and ¥4,205 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income. (3) The amount includes ¥24,978 million and ¥25,128 million related to MHFG’s net operating loss carryforwards resulting mainly from intercompany capital transactions in relation to the share buyback conducted by MHSC as of March 31, 2023 and 2024, respectively. The tax effect of the net operating loss carryforwards is fully offset by ¥24,978 million and ¥25,128 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income.
Breakdown of Net Operating Loss Carryforwards by Tax Jurisdiction	The following table and accompanying footnotes provide a breakdown of deferred tax assets and the valuation allowance recognized in respect of net operating loss carryforwards by tax jurisdiction and by year of expiration as of March 31, 2023 and 2024: Deferred tax assets Valuation allowance Deferred tax assets, net of valuation allowance (in billions of yen) 2023 Japan (1) 89 (75 ) 14 The United States 1 —  1 The United Kingdom (2) 77 (77 ) —  Others 1 —  1 Total 168 (152 ) 16 2024 Japan (3) 56 (34 ) 22 The United States 4 —  4 The United Kingdom (2) 88 (88 ) —  Others 1 —  1 Total 150 (123 ) 26 Notes: (1) ¥49 billion of the Japan deferred tax assets of ¥89 billion is related to MHSC, which is substantially offset by a valuation allowance, and will expire during the fiscal year ending March 31, 2026. ¥25 billion of the Japan deferred tax assets of ¥89 billion is related to MHFG, which is fully offset by a valuation allowance, and will mostly expire during the fiscal year ending March 31, 2032. (2) The United Kingdom net operating loss carryforwards may be carried forward indefinitely for tax purposes. (3) ¥25 billion of the Japan deferred tax assets of ¥56 billion is related to MHFG, which is fully offset by a valuation allowance, and will mostly expire during the fiscal year ending March 31, 2032. ¥16 billion of the Japan deferred tax assets of ¥56 billion is related to MHBK and will mostly expire during the fiscal year ending March 31, 2034.
Roll-forward Valuation Allowance	The following table presents a roll-forward of the valuation allowance for the fiscal years ended March 31, 2022, 2023 and 2024:   2022     2023     2024   (in millions of yen) Balance at beginning of fiscal year 129,150 163,164 198,800 Changes that directly affected Income tax expense 16,196 (4,118 ) (38,055 ) Changes that did not affect Income tax expense: Expiration of net operating loss carryforwards —  —  —  Others 17,818 39,754 73,246 Total 17,818 39,754 73,246 Balance at end of fiscal year 163,164 198,800 233,991
Net Operating Losses Carryforwards by Expiration Date	At March 31, 2024, the MHFG Group had net operating loss carryforwards totaling ¥423 billion. These carryforwards are scheduled to expire as follows: Net operating loss carryforwards (1) (3) (in billions of yen) Fiscal year ending March 31: 2025 —  2026 16 2027 3 2028 —  2029 5 2030 and thereafter (2) 399 Total 423 Notes: (1) Net operating loss carryforwards related to Japanese local taxes recorded at MHFG in the fiscal year ended March 31, 2022 in the amount of ¥500 billion (tax effected ¥24 billion) are not included in the table. The net operating loss carryforwards are fully offset by valuation allowance and will mostly expire during the fiscal year ending March 31, 2032. (2) Including the net operating loss carryforwards which may be carried forward indefinitely in the United Kingdom. (3) Net operating loss carryforwards related to Japanese local taxes recorded at MHBK in the fiscal year ended March 31, 2024 in the amount of ¥456 billion (tax effected ¥16 billion) are not included in the table. The net operating loss carryforwards will mostly expire during the fiscal year ending March 31, 2034.
Roll-forward of Unrecognized Tax Benefits	The following table is a roll-forward of unrecognized tax benefits for the fiscal years ended March 31, 2022, 2023 and 2024: 2022 2023 2024 (in millions of yen) Total unrecognized tax benefits at beginning of fiscal year 4,401 5,245 7,043 Gross amount of increases (decreases) related to positions taken during prior years (576 ) (438 ) 205 Gross amount of increases related to positions taken during the current year 954 1,748 1,080 Amount of decreases related to settlements —  —  (1,633 ) Foreign exchange translation 466 488 944 Total unrecognized tax benefits at end of fiscal year 5,245 7,043 7,639

Pension and other employee be_2

Pension and other employee benefit plans (Tables)	12 Months Ended
	Mar. 31, 2024
Components of Net Periodic Benefit Cost of Severance Indemnities and Pension Plans	The following table presents the components of net periodic benefit cost of the severance indemnities and pension plans for the fiscal years ended March 31, 2022, 2023 and 2024:   2022     2023     2024   (in millions of yen) Service cost-benefits earned during the fiscal year 33,190 30,460 28,936 I nterest costs on projected benefit obligations 5,636 6,917 9,982 Expected return on plan assets (37,051 )   (36,322 )  (34,565 )  Amortization of prior service cost (benefits) (4,820 ) (4,854 ) (4,890 ) Amortization of net actuarial loss (gain) (20,485 ) (19,453 ) (29,045 ) Special termination benefits 10,791 7,269 1,244 Loss (gain) on settlement —  —  2,210 Other —  —  3,179 Net periodic benefit cost (12,739 ) (15,983 ) (22,948 )
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss) Before-Tax	Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss) before-tax   2023     2024   (in millions of yen) Net actuarial gain (loss) 122,331    138,987    Amortization of net actuarial loss (gain) (19,453 ) (29,045 ) Settlement loss (gain) of net actuarial loss (gain) —  2,210 Amortization of prior service cost (benefits) (4,854 ) (4,890 ) Total recognized in other comprehensive income (loss) before-tax 98,024 107,262
Weighted-Average Assumptions Used to Determine Benefit Obligations and Net Periodic Benefit Cost	Weighted-average assumptions used to determine benefit obligations and net periodic benefit cost are as follows:   2022     2023     2024   Weighted-average assumptions used to determine benefit obligations at fiscal year end: Discount rates 0.52 % 0.82 % 1.00 % Rates of increase in future compensation levels 2.00 % 2.00 % 2.00 % Interest credit rates 4.39 % 4.45 % 4.52 %   2022     2023     2024   Weighted-average assumptions used to determine net periodic benefit cost during the year: Discount rates 0.38 % 0.52 % 0.82 % Rates of increase in future compensation levels 1.80 % 2.00 % 2.00 % Expected rates of return on plan assets 1.54 % 1.72 % 1.66 % Interest credit rates 4.38 % 4.39 % 4.45 %
Combined Funded Status and Amounts Recognized in Accompanying Consolidated Balance Sheets	The following table sets forth the combined funded status and amounts recognized in the accompanying consolidated balance sheets at March 31, 2023 and 2024 for the plans of MHFG and its subsidiaries: 2023 2024 (in millions of yen) Change in benefit obligations: Benefit obligations at beginning of fiscal year 1,377,739 1,287,692 Service cost 30,460 28,936 Interest cost 6,917 9,982 Plan participants’ contributions 1,053 1,026 Actuarial loss (gain) (48,856 ) (23,767 ) Foreign exchange translation 3,250 6,408 Benefits paid (55,332 ) (54,458 ) Lump-sum (27,539 ) (17,838 ) Settlement —  (19,974 ) Other —  (1,045 ) Benefit obligations at end of fiscal year 1,287,692 1,216,964 Change in plan assets: Fair value of plan assets at beginning of fiscal year 2,114,011 2,032,215 Actual return (negative return) on plan assets 92,893 140,967 Foreign exchange translation 3,158 7,204 Partial withdrawal of assets from employee retirement benefits (Note) (147,181 ) (179,437 ) Employer contributions 23,613 31,327 Plan participants’ contributions 1,053 1,026 Benefits paid (55,332 ) (54,458 ) Settlement —  (20,549 ) Other —  (1,677 ) Fair value of plan assets at end of fiscal year 2,032,215 1,956,619 Funded status 744,523 739,655 Amounts recognized in the consolidated balance sheets consist of: Prepaid pension cost 768,998 763,254 Accrued pension liability (24,475 ) (23,600 ) Net amount recognized 744,523 739,655 2023 2024 (in millions of yen) Amounts recognized in Accumulated other comprehensive income (loss) before-tax Prior service benefits (cost) 58,173 53,216 Net actuarial gain (loss) 524,571 636,790 Net amount recognized 582,744 690,007 Note: During the fiscal years ended March 31, 2023 and 2024, certain subsidiaries of MHFG partially withdrew assets from employee retirement benefit trusts, which were established for the payment of employees’ severance pay and retirement pensions. Overall, the trusts remain in overfunded status as of March 31, 2024. No gains or losses have been recognized as a result of these transactions.
Plans with Projected Benefit Obligations in Excess of Plan Assets and Plans with Accumulated Benefit Obligations in Excess of Plan Assets	The following table shows the projected benefit obligations and the fair value of plan assets for the plans of MHFG and its subsidiaries with projected benefit obligations in excess of plan assets, and the accumulated benefit obligations and the fair value of plan assets for the plans with accumulated benefit obligations in excess of plan assets at March 31, 2023 and 2024: 2023 2024 (in millions of yen) Plans with projected benefit obligations in excess of plan assets: Projected benefit obligations 29,389 27,787 Fair value of plan assets 4,914 4,187 Plans with accumulated benefit obligations in excess of plan assets: Accumulated benefit obligations 29,389 27,787 Fair value of plan assets 4,914 4,187 Note: The plans with projected benefit obligations in excess of plan assets include those with accumulated benefit obligations in excess of plan assets.
Target Allocation for Plan Assets Excluding those of Employee Retirement Benefit Trusts	MHFG and certain subsidiaries’ target allocation for the plan assets, excluding those of the employee retirement benefit trusts, at March 31, 2024 is as follows: Asset category Asset ratio Japanese equity securities 3.00 % Japanese debt securities 32.00 % Foreign equity securities 26.00 % Foreign debt securities 24.00 % General account of life insurance companies 10.00 % Other 5.00 % Total 100.00 % Note: General account of life insurance companies is a contract with life insurance companies which guarantees payments of principal and predetermined interest payments.
Fair Value of Plan Assets by Asset Category	The following table presents the fair value of plan assets of MHFG and its subsidiaries at March 31, 2023 and 2024, by asset class. For the detailed information on fair value measurements, including descriptions of Level 1, 2 and 3 of the fair value hierarchy and the valuation methodologies, see Note 26 “Fair value.” 2023 2024 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (in billions of yen) Japanese equity securities: Common stocks (1) 1,018 —  —  1,018 907 —  —  907 Pooled funds (2) 5 6 —  11 5 8 —  13 Japanese debt securities: Government bonds 123 —  —  123 85 —  —  85 Pooled funds (2) —  8 —  8 —  9 —  9 Other —  21 —  21 —  18 —  18 Foreign equity securities: Common stocks 94 —  —  94 152 —  —  152 Pooled funds (2) —  8 —  8 —  10 —  11 Foreign debt securities: Government bonds 173 14 —  187 148 20 —  168 Pooled funds (2) —  3 —  3 —  3 —  3 Other —  15 —  15 —  31 —  31 General account of life insurance companies (3) —  113 —  113 —  117 —  117 Other 101 (4) 5 —  106 38 (4) (6 ) —  32 Plan assets measured at net asset value (5) 325 410 Total assets at fair value 1,514 193 —  2,032 1,336 210 —  1,957 Notes: (1) This class represents equity securities held in the employee retirement benefit trusts of ¥1,018 billion and ¥907 billion carried at fair value at March 31, 2023 and 2024, respectively, which are well-diversified across industries. (2) These classes primarily include pension investment fund trusts. Investments in these classes are generally measured at fair value and can be redeemed within a short-term period upon request. (3) Investments in this class are measured at conversion value, which is equivalent to fair value. (4) Amounts primarily include cash and short-term assets carried at fair value. (5) In accordance with ASC 820, certain plan assets that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy.
Forecasted Benefit Payments Including Effect of Expected Future Service	The following table presents forecasted benefit payments including the effect of expected future service for the fiscal years indicated: (in millions of yen) Fiscal year ending March 31: 2025 75,229 2026 75,337 2027 74,087 2028 76,580 2029 75,596 2030-2034 324,753

Derivative financial instrume_2

Derivative financial instruments (Tables)	12 Months Ended
	Mar. 31, 2024
Summary of Notional and Fair Value Amounts of Derivative Instruments Outstanding	Fair value Derivative receivables (2) Derivative payables (2) 2023 Notional amount (1) Designated as hedges Not designated as hedges Designated as hedges Not designated as hedges (in billions of yen) Interest rate contracts 1,991,016  —  8,374  —  8,517 Foreign exchange contracts 257,392 —  4,222 —  4,013 Equity-related contracts 7,149 —  145 —  197 Credit-related contracts 22,748 —  144 —  126 Other contracts 898 —  47 —  43 Total 2,279,203 —  12,932 —  12,896 Fair value Derivative receivables (2) Derivative payables (2) 2024 Notional amount (1) Designated as hedges Not designated as hedges Designated as hedges Not designated as hedges (in billions of yen) Interest rate contracts 2,297,499 —  8,668 —  8,712 Foreign exchange contracts 300,337 —  5,612 —  5,582 Equity-related contracts 15,914 —  340 —  394 Credit-related contracts 22,969 —  214 —  180 Other contracts 1,039 —  40 —  50 Total 2,637,757 —  14,874 —  14,918 Notes: (1) Notional amount includes the sum of gross long and gross short third-party contracts. (2) Derivative receivables and payables are recorded in Trading account assets and Trading account liabilities, respectively.
Summary of Notional and Fair Value Amounts of Credit Derivatives	The following table summarizes the notional and fair value amounts of credit derivatives at March 31, 2023 and 2024: 2023 2024 Notional amount Fair value Notional amount Fair value (in billions of yen) Credit protection written: Investment grade 4,497 31 6,183 110 Non-investment 5,774 62 3,962 37 Total 10,271 93 10,145 147 Credit protection purchased 12,477 (75 ) 12,824 (114 ) Note: The rating scale is based upon either the external ratings or the internal ratings of the underlying reference credit. The lowest investment grade rating is considered to be BBB-, non-investment Non-investment
Maximum Potential Amount of Future Payments for Credit Protection Written by Expiration Period	The following table shows the maximum potential amount of future payments for credit protection written by expiration period at March 31, 2023 and 2024: Maximum payout/Notional amount   2023     2024   (in billions of yen) One year or less 331 1,254 After one year through five years 9,585 8,610 After five years 355 281 Total 10,271 10,145 Note: The maximum potential amount of future payments is the aggregate notional amount of the credit derivatives where the Group wrote the credit protection, and it has not been reduced by the effect of any amounts that the Group may possibly collect on the underlying assets and the related cash flows, nor netted against that of credit protection purchased.
Quantitative Information about Derivative Instruments with Credit-risk-related Contingent Features	The following table shows the quantitative information about derivative instruments with credit-risk-related contingent features at March 31, 2023 and 2024:   2023     2024   (in billions of yen) Aggregate fair value of derivative instruments with credit-risk-related contingent features in net liability positions 814 1,304 Collateral provided to counterparties in the normal course of business 663 1,025 Amount required to be posted as collateral or settled immediately if credit-risk-related contingent features were triggered 151 279
Not Designated as Hedging Instrument
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance	The following table summarizes gains and losses on derivatives not designated or qualifying as hedges during the fiscal years ended March 31, 2022, 2023 and 2024: Gains (losses) recorded in income   2022     2023     2024   (in millions of yen) Interest rate contracts (130,312 ) (508,743 ) (22,003 ) Foreign exchange contracts 145,979 317,459 387,591 Equity-related contracts 728,226 534,615 240,277 Credit-related contracts (Note) (13,877 ) (3,857 ) (3,053 ) Other contracts 7,762 59,599 (42,005 ) Total 737,778 399,073 560,806 Note: Amounts include the net gains (losses) of ¥(605) million, ¥(653) million and ¥(952) million on the credit derivatives economically managing the credit risk of loans during the fiscal years ended March 31, 2022, 2023 and 2024, respectively.

Commitments and contingencies (

Commitments and contingencies (Tables)	12 Months Ended
	Mar. 31, 2024
Summary of Maximum Potential Amount of Future Payments under Guarantees	The MHFG Group, when necessary, requires collateral such as cash, investment securities and real estate or third-party guarantees depending on the amount of credit risk involved, and employs means such as sub-participation 2023 Maximum potential/ Amount by expiration period One year After one year through five years After (in billions of yen) Performance guarantees 3,548 1,954 1,413 181 Guarantees on loans 228 149 26 53 Guarantees on securities 82 14 68 —  Other guarantees 3,306 2,339 869 98 Guarantees for the repayment of trust principal 18 —  8 10 Liabilities of trust accounts 554 97 282 175 Derivative financial instruments 83,420 53,774 24,954 4,692 2024 Maximum potential/ Amount by expiration period One year After one year through five years After five (in billions of yen) Performance guarantees 3,896 2,390 1,305 201 Guarantees on loans 348 258 54 36 Guarantees on securities 93 42 51 —  Other guarantees 3,543 2,809 614 120 Guarantees for the repayment of trust principal 16 —  7 10 Liabilities of trust accounts 599 165 225 209 Derivative financial instruments 113,108 78,356 29,674 5,077
Summary of Contractual Amounts with Regard to Undrawn Commitments	The table below summarizes the contractual amounts with regard to these undrawn commitments at March 31, 2023 and 2024: 2023 2024 (in billions of yen) Commitments to extend credit (Note) 100,973 115,577 Commercial letters of credit 1,336 1,778 Total 102,309 117,355 Note: Commitments to extend credit include commitments to invest in securities.
Schedule of Balance Sheet Information Related to operating lease	The following table presents the consolidated balance sheet information related to operating leases as of March 31, 2023 and 2024: 2023 2024 (in millions of yen, except for remaining lease term and discount rate) Right-of-use (Note) 549,668 522,936 Lease liabilities (Note) 571,087 548,699 Weighted average: Remaining lease term 14.7 years    14.0 years Discount rate 0.66 % 0.97 % Note: Right-of-use
Schedule of operating lease cost and supplemental cash flow information	The following table presents lease cost and supplemental information related to operating leases for the fiscal years ended March 31, 2022, 2023 and 2024: 2022 2023 2024 (in millions of yen) Lease cost (Note) 111,907 101,808 104,314 Right-of-use 51,901 65,417 52,831 Operating cash flows 101,223 86,329 83,100 Note: Lease cost for operating leases are included in Occupancy expenses on the consolidated statements of income. The Group’s variable lease costs and costs for leases with terms of twelve months or less are not significant.
Future Minimum Lease Payments for Capitalized Leases and Rental Payments for Operating Leases	The following table shows future lease payments under operating leases as of March 31, 2024: As of March 31, 2024 (in millions of yen) Fiscal year ending March 31: 2025 80,982 2026 61,337 2027 49,138 2028 38,925 2029 33,301 2030 and thereafter 314,213 Total lease payments 577,895 Amount representing interest 29,196 Total lease liabilities for operating leases 548,699
Performance guarantees, Guarantees on loans, Guarantees on securities and Other guarantees
Summary of Maximum Potential Amount of Future Payments under Guarantees	The table below presents the maximum potential amount of future payments of performance guarantees, guarantees on loans, guarantees on securities and other guarantees classified based on internal ratings at March 31, 2023 and 2024: 2023 2024 (in billions of yen) Investment grade 5,587 6,095 Non-investment 1,577 1,784 Total 7,164 7,879 Note: Investment grade in the internal rating scale generally corresponds to BBB-

Variable interest entities an_2

Variable interest entities and securitizations (Tables)	12 Months Ended
	Mar. 31, 2024
Schedule of Variable Interest Entities	The table below shows the consolidated assets of the MHFG Group’s consolidated VIEs as well as total assets and maximum exposure to loss for its significant unconsolidated VIEs, in which the Group has determined that its maximum exposure to loss is greater than specific thresholds or meets certain other criteria as of March 31, 2023 and 2024: Consolidated VIEs Significant unconsolidated VIEs 2023 Consolidated assets Total assets Maximum exposure to loss (in billions of yen) Asset-backed commercial paper/loan programs 3,082 —  —  Asset-backed securitizations 1,514 224 134 Investments in securitization products 387 —  —  Investment funds 2,294 3,397 845 Trust arrangements and other 4,877 —  —  Total 12,154 3,621 979 Consolidated VIEs Significant unconsolidated VIEs 2024 Consolidated assets Total assets Maximum exposure to loss (in billions of yen) Asset-backed commercial paper/loan programs 3,370 —  —  Asset-backed securitizations 1,668 175 96 Investments in securitization products 385 —  —  Investment funds 1,908 6,322 1,113 Trust arrangements and other 5,300 —  —  Total 12,631 6,497 1,209
Unconsolidated VIEs
Schedule of Variable Interest Entities	The tables below present the carrying amounts and classification of assets and liabilities on the MHFG Group’s balance sheets that relate to its variable interests in significant unconsolidated VIEs, as of March 31, 2023 and 2024: Assets on the MHFG Group’s balance sheets related to unconsolidated VIEs: 2023 2024 (in billions of yen) Trading account assets 83 97 Investments 482 726 Loans 154 137 Total    719    960 Liabilities on the MHFG Group’s balance sheets and maximum exposure to loss related to unconsolidated VIEs: 2023 2024 (in billions of yen) Trading account liabilities 1 3 Total 1 3 Maximum exposure to loss (Note)    979  1,209 Note: This represents the maximum amount the Group could possibly be required to record in its consolidated statements of income associated with on-balance-sheet off-balance-sheet

Noninterest income (Tables)

Noninterest income (Tables)	12 Months Ended
	Mar. 31, 2024
Summary of Noninterest Income	Details of Noninterest income for the fiscal years ended March 31, 2022, 2023 and 2024 are as follows: 2022 2023 2024 (in millions of yen) Fee and commission income: Securities-related business (1) 184,014 190,026 246,865 Deposits-related business (1) 15,358 15,540 15,591 Lending-related business (2) (4) 162,953 193,838 232,626 Remittance business (1) 103,979 104,201 106,762 Asset management business (1) 122,014 109,358 115,504 Trust-related business (1) 141,365 130,576 136,800 Agency business (1) 36,899 36,529 38,329 Guarantee-related business (3) 35,296 41,150 43,791 Fees for other customer services (1) 178,122 163,127 181,558 Total Fee and commission income 980,000 984,345 1,117,826 Foreign exchange gains (losses)—net (3) 91,611 189,526 (19,390 ) Trading account gains (losses)—net (2) (491,947 ) (603,910 ) 390,260 Investment gains (losses)—net: Debt securities (3) (14,777 ) 5,167 (6,446 ) Equity securities (3) (60,563 ) 135,601 1,010,288 Equity in earnings (losses) of equity method investees—net (3) 34,587 (26,999 ) 19,791 Gains on disposal of premises and equipment (3) 9,943 4,920 10,128 Other noninterest income (2) (5) 120,936 199,453 221,273 Total 669,790 888,103 2,743,729 Notes: (1) These amounts are revenues from contracts within the scope of ASC 606, “Revenue from contracts with customers” (“ASC 606”). (2) Part of these amounts are considered to be revenues from contracts that are within the scope of ASC 606. (3) These amounts are revenues from contracts that do not meet the scope of ASC 606. (4) Most of the lending-related fees such as commitment fees and arrangement fees are not within the scope of ASC 606. (5) These amounts include the net unrealized gains resulting from changes in fair values of structured notes that contain embedded derivatives. See Note 26 “Fair value” for further details.

Trading account gains and los_2

Trading account gains and losses (Tables)	12 Months Ended
	Mar. 31, 2024
Trading Account Gains And Losses [Abstract]
Net Trading Gains and Losses	Net trading gains (losses) for the fiscal years ended March 31, 2022, 2023 and 2024 are comprised of the following: 2022 2023 2024 (in millions of yen) Trading account gains (losses)—net: Trading securities (1,230,330 ) (1,003,636 ) (171,498 ) Derivative contracts: Interest rate contracts (130,312 ) (508,743 ) (22,003 ) Foreign exchange contracts (1) 145,979 317,459 387,591 Equity-related contracts 728,226 534,615 240,277 Credit-related contracts (2) (13,272 ) (3,204 ) (2,101 ) Other contracts 7,762 59,599 (42,005 ) Total (491,947 ) (603,910 ) 390,260 Foreign exchange gains (losses)—net (3) 91,611 189,526 (19,390 ) Net trading gains (losses) (400,336 ) (414,384 ) 370,870 Notes: (1) Amounts include gains and losses on currency swaps. (2) Amounts do not include the net gains (losses) of ¥(605) million, ¥(653) million and ¥(952) million on the credit derivatives economically managing the credit risk of loans during the fiscal years ended March 31, 2022, 2023 and 2024, respectively. The net gains (losses) is recorded in Other noninterest income (expenses). (3) Amounts include realized and unrealized gains and losses on both derivative instruments and nonderivative instruments. Amounts on derivative instruments include gains and losses on forward foreign exchange contracts and currency options. Amounts on nonderivative instruments include translation gains and losses related to foreign currency-denominated debt securities reported as Trading securities.

Fair value (Tables)

Fair value (Tables)	12 Months Ended
	Mar. 31, 2024
Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis, Including Fair Value Option Elected	Assets and liabilities measured at fair value on a recurring basis at March 31, 2023 and 2024, including those for which the MHFG Group has elected the fair value option, are summarized below: 2023 Level 1 Level 2 Level 3 Assets/ Liabilities measured at fair value (in billions of yen) Assets: Trading securities (1) Japanese government bonds 1,187 7 —  1,194 Japanese local government bonds —  138 —  138 U.S. Treasury bonds and federal agency securities 1,917 1,377 —  3,294 Other foreign government bonds 658 786 —  1,444 Agency mortgage-backed securities —  5,309 —  5,309 Certificates of deposit and commercial paper —  516 —  516 Corporate bonds and other (2) —  2,406 47 2,453 Equity securities 1,859 370 21 2,250 Trading securities measured at net asset value (3) 111 Derivative financial instruments: Interest rate contracts 218 8,103 53 8,374 Foreign exchange contracts —  4,200 22 4,222 Equity-related contracts 39 73 33 145 Credit-related contracts —  143 1 144 Other contracts 15 12 20 47 Available-for-sale Japanese government bonds 15,771 678 —  16,449 Japanese local government bonds —  555 —  555 U.S. Treasury bonds and federal agency securities 376 —  —  376 Other foreign government bonds 322 986 —  1,308 Agency mortgage-backed securities —  522 —  522 Residential mortgage-backed securities —  34 13 47 Commercial mortgage-backed securities —  862 —  862 Japanese corporate bonds and other debt securities —  2,008 101 2,109 Foreign corporate bonds and other debt securities —  916 90 1,006 Equity securities: Equity securities with readily determinable fair values 3,052 161 —  3,213 Equity securities measured at net asset value (3) 271 Other investments —  —  63 63 Total assets measured at fair value on a recurring basis 25,414 30,162 464 56,422 Liabilities: Trading securities sold, not yet purchased 2,954 3,513 —  6,467 Derivative financial instruments: Interest rate contracts 244 8,271 2 8,517 Foreign exchange contracts —  4,005 8 4,013 Equity-related contracts 46 91 60 197 Credit-related contracts —  124 2 126 Other contracts 10 15 18 43 Long-term debt (4) —  1,844 836 2,680 Total liabilities measured at fair value on a recurring basis 3,254 17,863 926 22,043 2024 Level 1 Level 2 Level 3 Assets/ Liabilities measured at fair value (in billions of yen) Assets: Trading securities (1) Japanese government bonds 1,623 5   —  1,628 Japanese local government bonds —  135 —  135 U.S. Treasury bonds and federal agency securities 3,534 1,468 —  5,002 Other foreign government bonds 676 897 —  1,572 Agency mortgage-backed securities —  6,717 —  6,717 Certificates of deposit and commercial paper —  351 —  351 Corporate bonds and other (2) —  3,208 189 3,397 Equity securities 2,743 209 21 2,973 Trading securities measured at net asset value (3) 109 Derivative financial instruments: Interest rate contracts 14 8,640 14 8,668 Foreign exchange contracts —  5,610 2 5,612 Equity-related contracts 79 255 6 340 Credit-related contracts —  213 1 214 Other contracts 21 9 10 40 Available-for-sale Japanese government bonds 10,562 412 —  10,974 Japanese local government bonds —  584 —  584 U.S. Treasury bonds and federal agency securities 147 —  —  147 Other foreign government bonds 922 1,122 —  2,045 Agency mortgage-backed securities —  477 —  477 Residential mortgage-backed securities —  24 8 31 Commercial mortgage-backed securities —  801 4 804 Japanese corporate bonds and other debt securities —  1,666 167 1,833 Foreign corporate bonds and other debt securities —  795 23 818 Equity securities: Equity securities with readily determinable fair values 4,165 296 —  4,461 Equity securities measured at net asset value (3) 334 Other investments 1 —  80 80 Other assets 3 68 —  71 Total assets measured at fair value on a recurring basis 24,489 33,961 525 59,419 Liabilities: Trading securities sold, not yet purchased 3,445 2,258 —  5,703 Derivative financial instruments: Interest rate contracts 14 8,697 1 8,712 Foreign exchange contracts —  5,571 11 5,582 Equity-related contracts 105 213 76 394 Credit-related contracts —  174 6 180 Other contracts 13 26 10 50 Other short-term borrowings (4) —  153 —  153 Long-term debt (4) —  2,450 427 2,876 Other liabilities 3 68 —  71 Total liabilities measured at fair value on a recurring basis 3,580 19,610 531 23,721 Notes: (1) Trading securities include foreign currency denominated securities for which the MHFG Group elected the fair value option. (2) The amount includes CLO and convertible bonds, which are classified in Level 3. (3) In accordance with ASC 820, certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented for these classes of assets are intended to permit the reconciliation of the fair value hierarchy to the amounts presented in the statements of financial position. The amounts of unfunded commitments related to these investments at March 31, 2023 and 2024 were ¥52 billion and ¥41 billion, respectively. (4) Amounts represent items for which the Group elected the fair value option or for which it applied the practicability exception.
Reconciliation for All Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3)	The following table presents a reconciliation for all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the fiscal years ended March 31, 2023 and 2024: 2023 April 1, 2022 Gains (losses) in Earnings Gains (losses) in OCI Transfers into Level 3 Transfers out of Level 3 Purchases Sales Issuances Settle- ments March 31, 2023 Change in unrealized gains (losses) still (6) (in billions of yen) Assets: Trading securities: Residential mortgage- backed securities 8 (1 ) (2) —  —  —  —  (6 ) —  (1 ) —  —  Corporate bonds and other 71 4 (2) —  13 (15 ) 104 (46 ) —  (84 ) 47 —  Equity securities 28 —  (2) —  —  —  2 (6 ) —  (3 ) 21 (1 ) Derivative financial instruments, net (1) Interest rate contracts. 22 31 (2) —  —  —  —  —  —  (2 ) 51 (22 ) Foreign exchange contracts 32 (5 ) (2) —  —  —  —  —  —  (13 ) 14 (6 ) Equity-related contracts (14 ) (26 ) (2) —  —  —  —  —  —  13 (27 ) (107 ) Credit-related contracts 1 (1 ) (2) —  —  —  —  —  —  (1 ) (1 ) (5 ) Other contracts —  2 (2) —  —  —  —  —  —  —  2 2 Available-for-sale Residential mortgage- backed securities 18 —  (3) —  (4) —  —  —  —  —  (5 ) 13 —  Commercial mortgage-backed securities —  —  (3) —  (4) —  —  —  —  —  —  —  —  Japanese corporate bonds and other debt securities 315 —  (3) 3 (4) —  —  25 —  —  (242 ) 101 8 Foreign corporate bonds and other debt securities 117 —  (3) 1 (4) —  (54 ) 63 —  —  (37 ) 90 —  Other investments 56 3 (3) —  —  (1 ) 36 —  —  (31 ) 63 1 Liabilities: Trading securities sold, not yet purchased —  —  (2) —  —  —  (1 ) 1 —  —  —  —  Long-term debt 794 29 (5) 10 (4) 1 (2 ) —  —  323 (241 ) 836 60 2024 April 1, 2023 Gains (losses) in Earnings Gains (losses) in OCI Transfers into Level 3 Transfers out of Level 3 Purchases Sales Issuances Settle- ments March 31, 2024 Change in unrealized gains (losses) still held (6) (in billions of yen) Assets: Trading securities: Residential mortgage- backed securities —  — (2)   —   —  —  —  —  —  —  —  —  Corporate bonds and other 47 12 (2) —  15 (7 ) 214 (59 ) —  (34 ) 189 9 Equity securities 21 — (2) —  —  —  3 (1 ) —  (1 ) 21 —  Derivative financial instruments, net (1) Interest rate contracts. 51 (44 ) (2) —  —  (32 ) —  —  —  38 13 8 Foreign exchange contracts 14 (8 ) (2) —  —  —  —  —  —  (15 ) (9 ) (10 ) Equity-related contracts (27 ) (62 ) (2) —  —  (1 ) —  —  —  20 (70 ) (37 ) Credit-related contracts (1 ) (6 ) (2) —  —  —  —  —  —  2 (5 ) (3 ) Other contracts 2 (1 ) (2) —  —  —  —  —  —  (1 ) —  (1 ) Available-for-sale Residential mortgage- backed securities 13 — (3) —  (4) —  —  —  (2 ) —  (3 ) 8 —  Commercial mortgage-backed securities —  — (3) —  (4) —  —  4 —  —  —  4 —  Japanese corporate bonds and other debt securities 101 — (3) 9 (4) —  —  106 —  —  (49 ) 167 12 Foreign corporate bonds and other debt securities 90 8 (3) —  (4) —  (2 ) 10 —  —  (82 ) 23 (1 ) Other investments 63 1 (3) —  —  —  47 —  —  (31 ) 80 —  Liabilities: Trading securities sold, not yet purchased —  — (2) —  —  —  —  —  —  —  —  —  Long-term debt 836 (57 ) (5) (14 ) (4) 1 (285 ) —  —  276 (472 ) 427 (11 ) Notes: (1) Total Level 3 derivative exposures have been netted on the table for presentation purposes only. (2) Gains (losses) in Earnings are reported in Trading account gains (losses)—net, Foreign exchange gains (losses)—net or Other noninterest income (expenses). (3) Gains (losses) in Earnings are reported in Investment gains (losses)—net. (4) Gains (losses) in OCI are reported in Other comprehensive income (loss). (5) Gains (losses) in Earnings are reported in Other noninterest income (expenses). (6) Amounts represent total gains or losses recognized in earnings and other comprehensive income (loss) during the period. These gains or losses were attributable to the change in fair value relating to assets and liabilities classified as Level 3 that were still held at March 31, 2023 and 2024. The amounts of unrealized gains (losses) in other comprehensive income (loss) are related to Available-for-sale
Quantitative Information about Significant Unobservable Inputs Related to Material Classes of Level 3 Assets and Liabilities	The following table presents information about significant unobservable inputs related to the MHFG Group’s material classes of Level 3 assets and liabilities at March 31, 2023 and 2024: 2023 Products/Instruments Fair value Principal valuation technique Unobservable inputs Range of input values Average (4) (in billions of yen, except for percentages and basis points) Trading securities and Available-for-sale Residential mortgage-backed securities 13 Discounted cash flow Prepayment rate 0.2%–17.6% 4.4% Price-based Default rate 0.0%–2.2% 0.2% Recovery rate 100.0%–100.0% 100.0% Discount margin 30.0bps–167.1bps 47.0bps Corporate bonds and other debt securities 238 Discounted cash flow Prepayment rate (1) 21.7%–21.7% 21.7% Price-based Default rate (1) 0.2%–0.2% 0.2% Recovery rate (1) 40.5%–40.5% 40.5% Discount margin (1) 98.8bps–209.9bps 116.2bps Discount margin (2) 3.5bps–171.2bps 20.1bps Derivative financial instruments, net: Interest rate 51 Internal valuation model (3) IR – IR correlation 23.2%–100.00% 75.0% Foreign exchange contracts 14 Internal valuation model (3) FX – IR correlation 5.5%–58.2% 39.9% FX – FX correlation 39.0%–64.7% 51.9% Equity-related contracts (27 ) Internal valuation model (3) Equity – IR correlation 25.0%–25.0% 25.0% Equity – FX correlation 0.0%–60.0% 33.7% Equity correlation 73.9%–100.0% 96.7% Equity volatility 10.3%–95.4% 44.1% Credit-related contracts (1 ) Internal valuation model (3) Default rate 0.1%–12.2% 2.1% Other contracts 2 Internal valuation model (3) Commodity volatility 20.0%–54.5% 39.8% Long-term debt 836 Internal valuation model (3) IR – IR correlation 23.2%–100.0% 75.0% FX – IR correlation 5.5%–58.2% 39.9% FX – FX correlation 39.0%–64.7% 51.9% Equity – IR correlation 25.0%–25.0% 25.0% Equity – -16.3%–93.3% 0.0% Equity correlation 3.2%–100.0% 90.8% Equity volatility 5.9%–180.8% 34.1% Default rate 0.1%–13.1% 2.3% Credit correlation 47.6%–100.0% 68.3% 2024 Products/Instruments Fair value Principal valuation technique Unobservable inputs Range of input values Average (4) (in billions of yen, except for percentages and basis points) Trading securities and Available-for-sale Residential mortgage-backed securities 8 Discounted cash flow Prepayment rate 0.4%–6.2% 3.8% Price-based Recovery rate 100.0%–100.0% 100.0% Discount margin 30.0bps–65.0bps 40.1bps Commercial mortgage-backed securities 4 Discounted cash flow Price-based Discount margin 158.7bps–291.4bps 234.2bps Corporate bonds and other debt securities 380 Discounted cash flow Prepayment rate (1) 3.2%–3.2% 3.2% Price-based Default rate (1) 0.4%–0.4% 0.4% Recovery rate (1) 36.9%–36.9% 36.9% Discount margin (1) 56.9bps–56.9bps 56.9bps Discount margin (2) 38.2bps–187.7bps 63.6bps Derivative financial instruments, net: Interest rate contracts 13 Internal valuation model (3) IR – IR correlation 23.2%–100.0% 71.4% Foreign exchange contracts (9 ) Internal valuation model (3) FX – IR correlation 13.8%–72.5% 29.9% FX – FX correlation 39.0%–64.7% 51.9% Equity-related contracts (70 ) Internal valuation model (3) Equity – IR correlation 25.0%–25.0% 25.0% Equity – FX correlation 15.0%–60.0% 60.0% Equity volatility 9.8%–121.8% 42.1% Credit-related contracts (5 ) Internal valuation model (3) Default rate 0.0%–6.4% 1.4% Other contracts — Internal valuation model (3) Commodity volatility 0.0%–27.7% 23.7% Long-term debt 427 Internal valuation model (3) IR – IR correlation 23.2%–100.0% 71.4% FX – IR correlation 5.5%–72.5% 29.9% FX – FX correlation 39.0%–64.7% 51.9% Equity – IR correlation 25.0%–25.0% 25.0% Equity – FX correlation -17.8%–93.3% 0.0% Equity correlation 32.2%–100.0% 87.3% Equity volatility 9.8%–70.7% 25.8% Default rate 0.0%–9.5% 1.4% Notes: (1) These inputs are mainly used for determining the fair values of securitization products such as CDO, CLO and ABS, other than RMBS and CMBS. (2) This input is mainly used for determining the fair values of Japanese corporate bonds and foreign corporate bonds. (3) Internal valuation model includes discounted cash flow models and the Black-Scholes option pricing model. (4) Averages are calculated by weighting each input by the relative fair value of the respective financial instruments except for derivative related inputs where medians are used. (5) The range of inputs for equity securities is not disclosed, as there is a dispersion of values given the number of positions. IR = Interest rate FX = Foreign exchange
Summary of Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis	The following table shows the fair value hierarchy for these items as of March 31, 2023 and 2024: 2023 Total Level 1 Level 2 Level 3 Aggregate cost (in billions of yen) Assets: Loans 97 —  —  97 165 Loans held-for-sale 216 —  16 200 282 Equity securities (without readily determinable fair values) 4 —  4 —  5 Other investments 94 93 —  1 122 Premises and equipment—net 1 —  —  1 2 Total assets measured at fair value on a nonrecurring basis 412 93 20 299 576 2024 Total Level 1 Level 2 Level 3 Aggregate cost (in billions of yen) Assets: Loans 101 —  —  101 187 Loans held-for-sale 95 —  2 94 150 Equity securities (without readily determinable fair values) 34 —  2 31 39 Other investments 153 —  —  153 199 Premises and equipment—net —  —  —  —  6 Intangible assets —  —  —  —  1 Total assets measured at fair value on a nonrecurring basis 383 —  4 379 581 Note: The fair values may not be current as of the dates indicated, but rather as of the date the fair value change occurred. Accordingly, the carrying values may not equal current fair value.
Carrying Amounts and Fair Values of Certain Financial Instruments, Excluding Financial Instruments Carried at Fair Value on a Recurring Basis and Those outside Scope of ASC 825	The following table shows the carrying amounts and fair values at March 31, 2023 and 2024, of certain financial instruments, excluding financial instruments which are carried at fair value on a recurring basis and those outside the scope of ASC 825 such as equity method investments as defined in ASC 323, “Investments-Equity Method and Joint Ventures” (“ASC 323”) and lease contracts as defined in ASC 842, “Leases” (“ASC 842”): 2023 Carrying amount Estimated fair value Total Level 1 Level 2 Level 3 (in billions of yen) Financial assets: Cash and due from banks, interest-bearing deposits in other banks, call loans and funds sold, and receivables under resale agreements and securities borrowing transactions 83,226 83,226 66,498 16,728 —  Investments 2,050 1,915 800 1,115 —  Loans, net of allowance (Note) 93,291 94,605 —  —  94,605 Financial liabilities: Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions 64,618 64,618 —  64,618 —  Interest-bearing deposits 128,756 128,718 —  128,718 —  Due to trust accounts 749 749 —  749 —  Other short-term borrowings 3,397 3,397 —  3,397 —  Long-term debt 12,246 11,719 —  10,315 1,404 2024 Carrying amount Estimated fair value Total Level 1 Level 2 Level 3 (in billions of yen) Financial assets: Cash and due from banks, interest-bearing deposits in other banks, call loans and funds sold, and receivables under resale agreements and securities borrowing transactions 98,392 98,392 72,026 26,366 —  Investments 4,048 3,863 512 3,351 —  Loans, net of allowance (Note) 97,519 98,868 —  —  98,868 Financial liabilities: Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions 78,030 78,030 —  78,030 —  Interest-bearing deposits 135,447 135,397 —  135,397 —  Due to trust accounts 246 246 —  246 —  Other short-term borrowings 3,492 3,492 —  3,492 —  Long-term debt 13,380 13,031 —  11,681 1,350 Note: Loans, net of allowance include items measured at fair value on a nonrecurring basis.

Offsetting of financial asset_2

Offsetting of financial assets and financial liabilities (Tables)	12 Months Ended
	Mar. 31, 2024
Information of Offsetting of Financial Assets and Financial Liabilities	The following table provides information about the offsetting of financial assets and financial liabilities at March 31, 2023 and 2024. The table includes derivatives, repurchase and resale agreements, and securities lending and borrowing transactions that are subject to enforceable master netting arrangements or similar agreements irrespective of whether or not they are offset on the Group’s consolidated balance sheets. Gross amounts recognized Gross amounts offset on the balance sheet Net amounts presented on the (2) Amounts not offset on the balance sheet (3) Net amounts Financial instruments (4) Cash collateral (in billions of yen) 2023 Assets (1) Derivatives 12,932 —  12,932 (5) (10,476 ) (821 ) 1,635 Receivables under resale agreements 11,695 —  11,695 (6) (10,565 ) —  1,130 Receivables under securities borrowing transactions 1,892 —  1,892 (7) (1,866 ) —  26 Total 26,519 —  26,519 (22,907 ) (821 ) 2,791 Liabilities (1) Derivatives 12,896 —  12,896 (5) (10,141 ) (843 ) 1,912 Payables under repurchase agreements 25,737 —  25,737 (6) (25,113 ) —  624 Payables under securities lending transactions 886 —  886 (7) (755 ) —  131 Total 39,519 —  39,519 (36,009 ) (843 ) 2,667 2024 Assets (1) Derivatives 14,874 —  14,874 (5) (11,525 ) (1,065 ) 2,284 Receivables under resale agreements 20,535 —  20,535 (6) (19,431 ) —  1,103 Receivables under securities borrowing transactions 2,352 —  2,352 (7) (2,261 ) —  91 Total 37,761 —  37,761 (33,217 ) (1,065 ) 3,478 Liabilities (1) Derivatives 14,918 —  14,918 (5) (10,941 ) (1,137 ) 2,840 Payables under repurchase agreements 38,105 —  38,105 (6) (36,842 ) —  1,262 Payables under securities lending transactions 1,350 —  1,350 (7) (1,298 ) —  52 Other liabilities (8) 71 —  71 (60 ) —  11 Total 54,444 —  54,444 (49,142 ) (1,137 ) 4,166 Notes: (1) Amounts relating to master netting arrangements or similar agreements where the MHFG Group does not have the legal right of set-off over-the-counter OTC-cleared (2) Derivative assets and liabilities are recorded in Trading account assets and Trading account liabilities, respectively. (3) Amounts do not exceed the net amounts presented on the balance sheet and do not include the effect of overcollateralization, where it exists. (4) For derivatives, amounts include derivative assets or liabilities and securities collateral that are eligible for offsetting under enforceable master netting arrangements or similar agreements. (5) The amounts of derivative assets and liabilities subject to enforceable master netting arrangements or similar agreements were ¥12,574 billion and ¥12,432 billion, respectively, at March 31, 2023, and ¥13,930 billion and ¥13,933 billion, respectively, at March 31, 2024. (6) The amounts of Receivables under resale agreements and Payables under repurchase agreements subject to enforceable industry standard master repurchase agreements with netting terms were ¥10,587 billion and ¥25,147 billion, respectively, at March 31, 2023, and ¥19,470 billion and ¥37,042 billion, respectively, at March 31, 2024. (7) The amounts of Receivables under securities borrowing transactions and Payables under securities lending transactions subject to enforceable industry standard master lending agreements with netting terms were ¥1,892 billion and ¥758 billion, respectively, at March 31, 2023, and ¥2,352 billion and ¥1,303 billion, respectively, at March 31, 2024. (8) Amounts relate to transactions where the Group acts as lender in a securities lending agreement and receives securities that can be sold or pledged as collateral. In these transactions, the Group recognizes the securities received at fair value within Other assets and the obligation to return those securities as a liability within Other liabilities.

Repurchase agreements and sec_2

Repurchase agreements and securities lending transactions accounted for as secured borrowings (Tables)	12 Months Ended
	Mar. 31, 2024
Gross Amounts of Liabilities by Remaining Contractual Maturity	The following table shows the gross amounts of liabilities associated with repurchase agreements and securities lending transactions, by remaining contractual maturity at March 31, 2023 and 2024: Overnight and continuous Up to 30 days 31-90 days Greater than 90 days Total (in billions of yen) 2023 Repurchase agreements 2,285 16,508 5,471 1,473 25,737 Securities lending transactions 685 73 —  128 886 Total 2,970 16,581 5,471 1,601 26,623 2024 Repurchase agreements 18,661 11,040 5,415 2,989 38,105 Securities lending transactions 1,288 19 —  44 1,350 Total 19,949 11,058 5,415 3,033 39,455
Gross Amounts of Liabilities by Class of Underlying Collateral	The following table shows the gross amounts of liabilities associated with repurchase agreements and securities lending transactions, by class of underlying collateral at March 31, 2023 and 2024: Repurchase agreements Securities lending transactions (in billions of yen) 2023 Japanese government bonds and Japanese local government bonds 6,114 102 Foreign government bonds and foreign agency mortgage-backed securities 17,475 73 Commercial paper and corporate bonds 430 —  Equity securities 1,491 711 Other 227 —  Total 25,737 886 2024 Japanese government bonds and Japanese local government bonds 6,167 102 Foreign government bonds and foreign agency mortgage-backed securities 28,757 19 Commercial paper and corporate bonds 913 —  Equity securities 1,609 1,229 Other 658 —  Total (Note) 38,105 1,350

Related Party Transactions (Tab

Related Party Transactions (Table)	12 Months Ended
	Mar. 31, 2024
Related Party Transactions [Abstract]
Summary of financial information of groups equity method investees	Summarized financial information of the MHFG Group’s equity method investees as of March 31, 2023 and 2024, and for each of the three years ended March 31, 2024, is as follows: 2023 2024 (in billions of yen) Loans 6,037 6,924 Total assets 29,367 28,447 Deposits 6,216 2,684 Total liabilities 26,506 24,829 Total equity 2,861 3,618 Noncontrolling interests 16 29 2022 2023 2024 (in billions of yen) Total interest and dividend income    625    750    958 Total interest expense 182 239 384 Provision (credit) for credit losses 104 96 83 Net interest income after provision (credit) for credit losses 339 415 490 Income before income tax expense 332 261 394 Net income 246 194 298

Business segment information (T

Business segment information (Tables)	12 Months Ended
	Mar. 31, 2024
Reportable Segment Information Derived from Internal Management Reporting Systems, on Basis of Japanese GAAP	The reportable segment information, set forth below, is derived from the internal management reporting systems used by management to measure the performance of the Group’s operating segments. Management measures the performance of each of the operating segments in accordance with internal managerial accounting rules and practices. In addition, the format and information are presented primarily on the basis of Japanese GAAP. Therefore, they are not consistent with the consolidated financial statements prepared in accordance with U.S. GAAP. A reconciliation is provided for the total amount of all business segments’ “Net business profits (losses) + Net gains (losses) related to ETFs and others” with income before income tax expense under U.S. GAAP, and the total amount of all business segments’ “Fixed assets” with the total amount of Premises and equipment-net, right-of-use As background, effective as of April 1, 2023, MHFG partially restructured its in-house in-house MHFG (Consolidated) 2022 (1) RBC CIBC GCIBC GMC AMC Others (6) Total (in billions of yen) Gross profits + Net gains (losses) related to ETFs and others (2)   717.5   499.8   553.0   383.8    59.4    40.5 2,254.3 General and administrative expenses (3) 617.8 205.9 286.4 230.7 33.4 40.5 1,414.9 Equity in earnings (losses) of equity method investees—net 5.8 3.7 14.3 —  1.5 —  25.4 Amortization of goodwill and others 2.1 —  0.3 0.8 7.2 0.9 11.6 Net business profits (losses) (4) 103.4 297.4 280.5 152.3 20.3 (1.0 ) 853.1 Fixed assets (5) 486.9 161.7 165.8 87.9 —  794.7 1,697.2 MHFG (Consolidated) 2023 (1) RBC CIBC GCIBC GMC AMC Others (6) Total (in billions of yen) Gross profits + Net gains (losses) related to ETFs and others (2)   706.5   508.7   627.1   314.2    54.7    68.7 2,280.2 General and administrative expenses (3) 605.7 202.0 309.2 253.4 35.0 67.9 1,473.5 Equity in earnings (losses) of equity method investees—net (18.3 ) 6.3 20.3 —  —  3.5 11.8 Amortization of goodwill and others 2.0 —  0.7 0.7 6.8 0.9 11.4 Net business profits (losses) (4) 80.3 312.9 337.5 59.9 12.8 3.5 807.1 Fixed assets (5) 483.3 152.8 177.7 87.3 —  777.3 1,678.5 MHFG (Consolidated) 2024 (1) RBC CIBC GCIBC GMC AMC Others (6) Total (in billions of yen) Gross profits + Net gains (losses) related to ETFs and others (2) 749.2 556.3 670.2 432.4 57.2 206.8 2,672.2 General and administrative expenses (3) 651.1 217.7 352.4 307.4 36.1 117.0 1,681.9 Equity in earnings (losses) of equity method investees—net 6.9 7.6 22.0 —  (11.8 ) 1.4 26.2 Amortization of goodwill and others —  —  2.3 —  6.4 1.8 10.7 Net business profits (losses) (4) 105.0 346.1 337.4 125.0 2.7 89.4 1,005.8 Fixed assets (5) 533.8 157.1 197.9 90.3 —  885.4 1,864.6 Notes: (1) Income and expenses of foreign branches of MHBK and foreign subsidiaries with functional currencies other than Japanese Yen have been translated for purposes of segment reporting using the budgeted foreign currency rates. Prior period comparative amounts for such foreign currency income and expenses have been translated using current period budgeted foreign currency rates. (2) “Gross profits + Net gains (losses) related to ETFs and others” is reported instead of sales reported by general corporations. Gross profits is defined as the sum of net interest income, fiduciary income, net fee and commission income, net trading income and net other operating income. Net gains (losses) related to ETFs and others consist of net gains (losses) on ETFs held by MHBK and MHTB on their non-consolidated (3) “General and administrative expenses” excludes non-allocated (4) Net business profits (losses) is used in Japan as a measure of the profitability of core banking operations, and is defined as gross profits (as defined above) less general and administrative expenses (excluding non-allocated (5) “Fixed assets” is presented based on Japanese GAAP and corresponds to the total amount of the following U.S. GAAP accounts: Premises and equipment-net; right-of-use (6) “Others” includes the following items: • profits and expenses pertaining to consolidated subsidiaries that are not subject to allocation; • consolidating adjustments, including elimination of internal transaction between each segment; • equity in earnings (losses) of equity method investees—net that are not subject to allocation; and • profits and losses pertaining to derivative transactions that reflect the counterparty risk of the individual parties and other factors in determining fair market value.
Reconciliation of Total Net Business Profits under Internal Management Reporting Systems to Income Before Income Tax Expense on Consolidated Statements of Income	A reconciliation of “Net business profits (losses) + Net gains (losses) related to ETFs and others” for the fiscal years ended March 31, 2022, 2023 and 2024 presented above to income (loss) before income tax expense (benefit) shown on the consolidated statements of income and a reconciliation of “Fixed assets” at March 31, 2023 and 2024 to the total amount of Premises and equipment-net, right-of-use 2022 2023 2024 (in billions of yen) Net business profits (losses) + Net gains (losses) related to ETFs and others 853.1 807.1 1,005.8 Adjustment to reconcile management reporting to Japanese GAAP: General and administrative expenses: non-allocated 33.7 39.7 28.6 Expenses related to portfolio problems (including reversal of (provision for) general reserve for losses on loans) (255.9 ) (96.7 ) (114.0 ) Gains on reversal of reserves for possible losses on loans, and others 20.8 7.4 7.6 Net gains (losses) related to stocks—Net gains (losses) related to ETFs and others (45.8 ) 84.6 54.7 Net extraordinary gains (losses) 44.0 (10.6 ) 40.9 Others (46.1 ) (52.5 ) (68.8 ) Income before income tax expense under Japanese GAAP   603.9   779.0   955.0 Adjustment to reconcile Japanese GAAP to U.S. GAAP: Derivative financial instruments and hedging activities (124.0 ) (373.2 ) 50.5 Investments (600.1 ) (210.5 ) 571.7 Loans (18.3 ) (30.3 ) (8.8 ) Allowances for credit losses 51.5 (9.8 ) 25.3 Premises and equipment (68.5 ) (29.3 ) (55.1 ) Land revaluation 6.4 5.6 4.9 Business combinations 6.9 8.9 10.8 Pension liabilities (94.4 ) (71.6 ) (60.4 ) Consolidation of variable interest entities 42.3 0.8 211.2 Foreign currency translation (51.0 ) (5.2 ) (83.2 ) Others 2.8 4.8 0.9 Income (loss) before income tax expense (benefit) under U.S. GAAP (242.5 ) 69.2 1,623.1
Reconciliation of Assets from Segment to Consolidated	2022 2023 2024 (in billions of yen) Fixed assets 1,697.2 1,678.5 1,864.6 U.S. GAAP adjustments (Note) 717.6 662.6 582.2 Premises and equipment-net, right-of-use 2,414.9   2,341.2   2,446.9   Note: The U.S. GAAP adjustments are primarily comprised of GAAP differences mainly from right-of-use

Foreign activities (Tables)

Foreign activities (Tables)	12 Months Ended
	Mar. 31, 2024
Text Block [Abstract]
Consolidated Income Statement and Total Assets Information by Major Geographic Area	The following table presents consolidated income statement and total assets information by major geographic area. Foreign activities are defined as business transactions that involve customers residing outside of Japan. However, as the MHFG Group’s operations are highly integrated globally, estimates and assumptions have been made for an allocation among the geographic areas. Americas Japan United States of America Others Europe Asia/Oceania excluding Japan, and others Total (in billions of yen) Fiscal year ended March 31, 2022: Total revenue (1) 991.1 562.9 41.7 184.8 333.2 2,113.7 Total expenses (2) 1,713.8 265.0 19.0 189.2 169.2 2,356.2 Income (loss) before income tax expense (benefit) (722.7 ) 297.9 22.7 (4.4 ) 164.0 (242.5 ) Net income (loss) (509.0 ) 275.2 18.3 (16.3 ) 130.3 (101.5 ) Total assets at end of fiscal year 155,111.2 36,765.7 3,667.9 15,795.9 20,210.0 231,550.7 Fiscal year ended March 31, 2023: Total revenue (1) 1,104.7 1,841.5 93.1 445.9 791.7 4,276.9 Total expenses (2) 1,784.1 1,455.4 84.7 413.0 470.5 4,207.7 Income (loss) before income tax expense (benefit) (679.4 ) 386.1 8.4 32.9 321.2 69.2 Net income (loss) (554.7 ) 297.2 1.8 19.9 269.8 34.0 Total assets at end of fiscal year 161,348.7 45,516.4 3,579.6 16,634.7 21,701.3 248,780.7 Fiscal year ended March 31, 2024: Total revenue (1) 2,827.1 3,584.4 198.5 803.7 1,097.1 8,510.7 Total expenses (2) 2,171.8 2,978.7 191.6 817.1 728.4 6,887.6 Income (loss) before income tax expense 655.3 605.6 6.8 (13.3 ) 368.6 1,623.1 Net income (loss) 449.0 491.1 (1.6 ) (50.0 ) 309.5 1,198.0 Total assets at end of fiscal year 170,063.8 57,036.0 4,483.0 19,142.1 21,448.2 272,173.2 Notes: (1) Total revenue is comprised of Interest and dividend income and Noninterest income. (2) Total expenses are comprised of Interest expense, Provision (credit) for credit losses and Noninterest expenses.

Mizuho Financial Group, Inc.,_2

Mizuho Financial Group, Inc., parent company (Tables)	12 Months Ended
	Mar. 31, 2024
Condensed Financial Information Disclosure [Abstract]
Condensed Balance Sheets	Condensed balance sheets 2023 2024 (in millions of yen) Assets: Cash and due from banking subsidiaries 47,425 23,394 Interest-bearing deposits in banking subsidiaries 450 431 Investments in subsidiaries and affiliated companies: Banking subsidiaries 7,996,767 8,542,884 Non-banking 1,075,322 1,305,643 Long-term loans receivable from subsidiaries: A banking subsidiary 8,768,725 9,567,224 A non-banking 444,000 444,000 Other assets 545,744 629,277 Total 18,878,433 20,512,853 Liabilities and shareholders’ equity: Short-term borrowings from a banking subsidiary 810,000 631,000 Long-term debt 8,741,729 9,546,009 Other liabilities 411,213 406,773 Shareholders’ equity 8,915,491 9,929,071 Total 18,878,433 20,512,853
Condensed Statements of Income	Condensed statements of income 2022 2023 2024 (in millions of yen) Income: Dividends from subsidiaries and affiliated companies: Banking subsidiaries 197,717 209,257 547,487 Non-banking 82,105 62,698 11,826 Management fees from subsidiaries 40,462 43,900 51,770 Interest income on loans and discounts 133,215 177,137 232,272 Gains on sales of investments in subsidiaries 53,005 —  —  Other income 11,319 37,319 4,444 Total   517,823   530,311 847,800 Expenses: Operating expenses 43,192 52,887 60,037 Interest expense 130,453 175,723 230,780 Losses on sales of investments in a subsidiary 26,606 —  —  Other expense 5,946 2,768 11,286 Total 206,197 231,378 302,103 Equity in undistributed net income (loss) of subsidiaries and affiliated companies—net (505,891 ) (307,879 ) 365,266 Income (loss) before income tax expense (benefit) (194,265 ) (8,946 ) 910,964 Income tax expense (benefit) (89,543 ) 5,063 (1,509 ) Net income (loss) (104,722 ) (14,009 ) 912,473
Condensed Statements of Cash Flows	Condensed statements of cash flows 2022 2023 2024 (in millions of yen) Cash flows from operating activities: Net income (loss) (104,722 ) (14,009 ) 912,473 Adjustments and other 351,484 394,191 (421,191 ) Net cash provided by operating activities 246,762 380,182 491,282 Cash flows from investing activities: Net change in loans (72,313 ) (511,934 ) (130,719 ) Purchases of investments in subsidiaries —  (179,210 ) (91,200 ) Proceeds from sales of investments in subsidiaries 452,500 721 —  Net change in other investing activities 208 (5,673 ) (9,983 ) Net cash provided by (used in) investing activities 380,395 (696,095 ) (231,902 ) Cash flows from financing activities: Net change in short-term borrowings (95,000 ) 55,000 (179,000 ) Proceeds from issuance of long-term debt 930,033 1,497,032 1,363,655 Repayment of long-term debt (1,256,720 ) (1,030,099 ) (1,232,936 ) Purchases of treasury stock (1,927 ) (1,575 ) (2,478 ) Dividends paid (196,783 ) (209,457 ) (234,787 ) Net change in other financing activities 44 1,117 2,116 Net cash provided by (used in) financing activities (620,353 ) 312,018 (283,431 ) Net increase (decrease) in cash and cash equivalents 6,804 (3,895 ) (24,050 ) Cash and cash equivalents at beginning of fiscal year 44,966 51,770 47,875 Cash and cash equivalents at end of fiscal year 51,770 47,875 23,825

Basis of Presentation and Sum_4

Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Mar. 31, 2024 ¥ / shares shares
Stock Acquisition Rights [Member]
Disclosure of Accounting Policies [Line Items]
Number of shares | shares	100
Exercise price | ¥ / shares	¥ 1
Contractual term	20 years
Minimum
Disclosure of Accounting Policies [Line Items]
Period in which obligors generally determined to be substantially bankrupt, past due (in months)	6 months
Minimum | Software and Software Development Costs
Disclosure of Accounting Policies [Line Items]
Estimated useful life	5 years
Maximum | Software and Software Development Costs
Disclosure of Accounting Policies [Line Items]
Estimated useful life	10 years
Impaired loans | Minimum
Disclosure of Accounting Policies [Line Items]
Number of days past due	90 days
Customer Relationships [Member] | Shinko Securities Company Limited
Disclosure of Accounting Policies [Line Items]
Weighted-average amortization period	16 years
Customer Relationships [Member] | Asset Management Company
Disclosure of Accounting Policies [Line Items]
Weighted-average amortization period	16 years 10 months 24 days

Basis of Presentation and Sum_5

Basis of Presentation and Summary of Significant Accounting Policies (Useful Lives of Premises and Equipment) (Detail)	Mar. 31, 2024
Minimum | Buildings
Disclosure of Basis of Presentation and Summary of Significant Accounting Policies [Line Items]
Years	3 years
Minimum | Equipment and furniture
Disclosure of Basis of Presentation and Summary of Significant Accounting Policies [Line Items]
Years	2 years
Maximum | Buildings
Disclosure of Basis of Presentation and Summary of Significant Accounting Policies [Line Items]
Years	50 years
Maximum | Equipment and furniture
Disclosure of Basis of Presentation and Summary of Significant Accounting Policies [Line Items]
Years	20 years

Investments - Amortized Cost, G

Investments - Amortized Cost, Gross Unrealized Gains and Losses, and Fair Value of Available-for-Sale and Held-to-Maturity Securities (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2024	Mar. 31, 2023
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities		¥ 38,442	¥ 71,417
Fair value, available-for-sale securities		17,713,335	23,233,769
Amortized cost, held-to-maturity securities		4,047,547	2,050,107
Total		3,862,924
Debt securities | Japanese government bonds
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities		2,956	37,496
Debt securities | Japanese local government bonds
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities		7,574	5,628
Debt securities | U.S. Treasury bonds and federal agency securities
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities		252	7,289
Debt securities | Other foreign government bonds
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities		1,755	2,261
Debt securities | Agency mortgage-backed securities
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities	[1]	18,225	11,307
Debt securities | Residential mortgage-backed securities
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities		767	866
Debt securities | Commercial mortgage-backed securities
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities		789	451
Debt securities | Japanese corporate bonds and other debt securities
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities		5,909	4,538
Debt securities | Foreign corporate bonds and other debt securities
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities		214	1,581
Available-for-sale securities | Debt securities
Schedule of Investments [Line Items]
Amortized cost, net available-for-sale securities	[2],[3]	17,712,059	23,279,549
Gross unrealized gains, available-for-sale securities		39,718	25,637
Gross unrealized losses, available-for-sale securities		38,442	71,417
Fair value, available-for-sale securities		17,713,335	23,233,769
Available-for-sale securities | Debt securities | Japanese government bonds
Schedule of Investments [Line Items]
Amortized cost, net available-for-sale securities	[2],[3]	10,968,212	16,483,722
Gross unrealized gains, available-for-sale securities		9,137	3,067
Gross unrealized losses, available-for-sale securities		2,956	37,496
Fair value, available-for-sale securities		10,974,393	16,449,293
Available-for-sale securities | Debt securities | Japanese local government bonds
Schedule of Investments [Line Items]
Amortized cost, net available-for-sale securities	[2],[3]	591,218	560,093
Gross unrealized gains, available-for-sale securities		95	198
Gross unrealized losses, available-for-sale securities		7,574	5,628
Fair value, available-for-sale securities		583,739	554,663
Available-for-sale securities | Debt securities | U.S. Treasury bonds and federal agency securities
Schedule of Investments [Line Items]
Amortized cost, net available-for-sale securities	[2],[3]	147,186	382,990
Gross unrealized gains, available-for-sale securities		118	0
Gross unrealized losses, available-for-sale securities		252	7,289
Fair value, available-for-sale securities		147,052	375,701
Available-for-sale securities | Debt securities | Other foreign government bonds
Schedule of Investments [Line Items]
Amortized cost, net available-for-sale securities	[2],[3]	2,044,611	1,309,473
Gross unrealized gains, available-for-sale securities		1,739	661
Gross unrealized losses, available-for-sale securities		1,755	2,261
Fair value, available-for-sale securities		2,044,595	1,307,873
Available-for-sale securities | Debt securities | Agency mortgage-backed securities
Schedule of Investments [Line Items]
Amortized cost, net available-for-sale securities	[2],[3],[4]	495,057	532,364
Gross unrealized gains, available-for-sale securities	[4]	140	1,140
Gross unrealized losses, available-for-sale securities	[4]	18,225	11,307
Fair value, available-for-sale securities	[4]	476,972	522,197
Available-for-sale securities | Debt securities | Residential mortgage-backed securities
Schedule of Investments [Line Items]
Amortized cost, net available-for-sale securities	[2],[3]	32,120	48,257
Gross unrealized gains, available-for-sale securities		30	71
Gross unrealized losses, available-for-sale securities		767	866
Fair value, available-for-sale securities		31,383	47,462
Available-for-sale securities | Debt securities | Commercial mortgage-backed securities
Schedule of Investments [Line Items]
Amortized cost, net available-for-sale securities	[2],[3]	800,224	856,708
Gross unrealized gains, available-for-sale securities		4,787	5,157
Gross unrealized losses, available-for-sale securities		789	451
Fair value, available-for-sale securities		804,222	861,414
Available-for-sale securities | Debt securities | Japanese corporate bonds and other debt securities
Schedule of Investments [Line Items]
Amortized cost, net available-for-sale securities	[2],[3]	1,817,009	2,100,733
Gross unrealized gains, available-for-sale securities		21,958	13,024
Gross unrealized losses, available-for-sale securities		5,909	4,538
Fair value, available-for-sale securities		1,833,057	2,109,219
Available-for-sale securities | Debt securities | Foreign corporate bonds and other debt securities
Schedule of Investments [Line Items]
Amortized cost, net available-for-sale securities	[2],[3],[5]	816,421	1,005,209
Gross unrealized gains, available-for-sale securities	[5]	1,713	2,319
Gross unrealized losses, available-for-sale securities	[5]	214	1,581
Fair value, available-for-sale securities	[5]	817,921	1,005,947
Held-to-maturity Securities | Debt securities
Schedule of Investments [Line Items]
Amortized cost, held-to-maturity securities	[2],[3]	4,047,547	2,050,107
Gross unrealized gains, held-to-maturity securities		9,421	2,574
Gross unrealized losses, held-to-maturity securities		194,044	137,573
Total		3,862,924	1,915,108
Held-to-maturity Securities | Debt securities | Japanese government bonds
Schedule of Investments [Line Items]
Amortized cost, held-to-maturity securities	[2],[3]	519,397	799,305
Gross unrealized gains, held-to-maturity securities		208	2,171
Gross unrealized losses, held-to-maturity securities		7,585	1,028
Total		512,020	800,448
Held-to-maturity Securities | Debt securities | Agency mortgage-backed securities
Schedule of Investments [Line Items]
Amortized cost, held-to-maturity securities	[2],[3],[6]	3,528,150	1,250,802
Gross unrealized gains, held-to-maturity securities	[6]	9,213	403
Gross unrealized losses, held-to-maturity securities	[6]	186,460	136,545
Total	[6]	¥ 3,350,904	¥ 1,114,660
[1]Agency mortgage-backed securities presented in this line consist of Japanese agency mortgage-backed securities, of which the fair values were ¥381,634 million at March 31, 2023, and ¥438,556 million at March 31, 2024. All Japanese agency mortgage-backed securities are issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise.[2]Accrued interest receivables are excluded from amortized cost, of which the amount were ¥5,637 million at March 31, 2023, and ¥15,708 million at March 31, 2024 and included in Accrued income.[3]Amortized cost, net of the allowance for credit losses, of which the amounts related to available-for-sale securities were ¥nil at both March 31, 2023 and 2024.[4]Agency mortgage-backed securities presented in this line consist of Japanese and Foreign agency mortgage-backed securities, of which the fair values were ¥522,166 million and ¥31 million, respectively, at March 31, 2023, and ¥476,947 million and ¥26 million, respectively, at March 31, 2024. All Japanese agency mortgage-backed securities are issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise. Foreign agency mortgage-backed securities primarily consist of Government National Mortgage Association (“Ginnie Mae”) securities, which are guaranteed by the United States government.[5]Other debt securities presented in this line primarily consist of Foreign negotiable certificates of deposit (“NCDs”) and asset-backed securities (“ABS”), of which the total fair values were ¥330,365 million at March 31, 2023, and ¥209,956 million at March 31, 2024.[6]All Agency mortgage-backed securities presented in this line are Ginnie Mae securities.

Investments - Amortized Cost,_2

Investments - Amortized Cost, Gross Unrealized Gains and Losses, and Fair Value of Available-for-Sale and Held-to-Maturity Securities (Parenthetical) (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023
Schedule of Investments [Line Items]
Fair value, available-for-sale securities	¥ 17,713,335	¥ 23,233,769
Accrued income
Schedule of Investments [Line Items]
Accrued interest receivables	260,000	198,000
Net of Allowance for Credit Loss [Member]
Schedule of Investments [Line Items]
Amortised cost net of allowance for credit loss available for sale securities	0	0
Debt securities | Negotiable certificates of deposits, asset- backed securities and collateral loan obligations
Schedule of Investments [Line Items]
Fair value, available-for-sale securities	209,956	330,365
Debt securities | Japanese agency mortgage-backed securities | Agency mortgage-backed securities
Schedule of Investments [Line Items]
Fair value, available-for-sale securities	476,947	522,166
Debt securities | Foreign agency mortgage-backed securities | Agency mortgage-backed securities
Schedule of Investments [Line Items]
Fair value, available-for-sale securities	26	31
Available-for sale and held-to-maturity securities | Accrued income
Schedule of Investments [Line Items]
Accrued interest receivables	¥ 15,708	¥ 5,637

Investments - Amortized Cost an

Investments - Amortized Cost and Fair Value of Available-for-Sale and Held-to-Maturity Securities by Contractual Maturity (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost	¥ 13,043,830
Due after one year through five years, amortized cost	2,557,103
Due after five years through ten years, amortized cost	1,223,953
Due after ten years, amortized cost	887,173
Total	17,712,059
Due in one year or less, amortized cost	100,005
Due after one year through five years, amortized cost	179,850
Due after five years through ten years, amortized cost	239,542
Due after ten years, amortized cost	3,528,150
Amortized cost, held-to-maturity securities	4,047,547	¥ 2,050,107
Due in one year or less, fair value	13,040,169
Due after one year through five years, fair value	2,556,290
Due after five years through ten years, fair value	1,228,299
Due after ten years, fair value	888,577
Total	17,713,335
Due in one year or less, fair value	100,213
Due after one year through five years, fair value	178,440
Due after five years through ten years, fair value	233,367
Due after ten years, fair value	3,350,904
Total	3,862,924
Debt securities | Japanese government bonds
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost	10,565,041
Due after one year through five years, amortized cost	11,922
Due after five years through ten years, amortized cost	391,249
Due after ten years, amortized cost	0
Total	10,968,212
Due in one year or less, amortized cost	100,005
Due after one year through five years, amortized cost	179,850
Due after five years through ten years, amortized cost	239,542
Due after ten years, amortized cost	0
Amortized cost, held-to-maturity securities	519,397
Due in one year or less, fair value	10,562,258
Due after one year through five years, fair value	11,912
Due after five years through ten years, fair value	400,223
Due after ten years, fair value	0
Total	10,974,393
Due in one year or less, fair value	100,213
Due after one year through five years, fair value	178,440
Due after five years through ten years, fair value	233,367
Due after ten years, fair value	0
Total	512,020
Debt securities | Japanese local government bonds
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost	72,554
Due after one year through five years, amortized cost	220,432
Due after five years through ten years, amortized cost	288,731
Due after ten years, amortized cost	9,501
Total	591,218
Due in one year or less, fair value	72,521
Due after one year through five years, fair value	219,353
Due after five years through ten years, fair value	282,856
Due after ten years, fair value	9,009
Total	583,739
Debt securities | U.S. Treasury bonds and federal agency securities
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost	147,186
Due after one year through five years, amortized cost	0
Due after five years through ten years, amortized cost	0
Due after ten years, amortized cost	0
Total	147,186
Due in one year or less, fair value	147,052
Due after one year through five years, fair value	0
Due after five years through ten years, fair value	0
Due after ten years, fair value	0
Total	147,052
Debt securities | Other foreign government bonds
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost	1,513,211
Due after one year through five years, amortized cost	526,826
Due after five years through ten years, amortized cost	3,293
Due after ten years, amortized cost	1,281
Total	2,044,611
Due in one year or less, fair value	1,512,511
Due after one year through five years, fair value	527,510
Due after five years through ten years, fair value	3,294
Due after ten years, fair value	1,281
Total	2,044,595
Debt securities | Agency mortgage-backed securities
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost	0
Due after one year through five years, amortized cost	0
Due after five years through ten years, amortized cost	912
Due after ten years, amortized cost	494,145
Total	495,057
Due in one year or less, amortized cost	0
Due after one year through five years, amortized cost	0
Due after five years through ten years, amortized cost	0
Due after ten years, amortized cost	3,528,150
Amortized cost, held-to-maturity securities	3,528,150
Due in one year or less, fair value	0
Due after one year through five years, fair value	0
Due after five years through ten years, fair value	904
Due after ten years, fair value	476,068
Total	476,972
Due in one year or less, fair value	0
Due after one year through five years, fair value	0
Due after five years through ten years, fair value	0
Due after ten years, fair value	3,350,904
Total	3,350,904
Debt securities | Residential mortgage-backed securities
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost	0
Due after one year through five years, amortized cost	0
Due after five years through ten years, amortized cost	0
Due after ten years, amortized cost	32,120
Total	32,120
Due in one year or less, fair value	0
Due after one year through five years, fair value	0
Due after five years through ten years, fair value	0
Due after ten years, fair value	31,383
Total	31,383
Debt securities | Commercial mortgage-backed securities
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost	12,480
Due after one year through five years, amortized cost	545,950
Due after five years through ten years, amortized cost	241,794
Due after ten years, amortized cost	0
Total	800,224
Due in one year or less, fair value	12,485
Due after one year through five years, fair value	547,001
Due after five years through ten years, fair value	244,736
Due after ten years, fair value	0
Total	804,222
Debt securities | Japanese corporate bonds and other debt securities
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost	270,114
Due after one year through five years, amortized cost	1,011,897
Due after five years through ten years, amortized cost	205,192
Due after ten years, amortized cost	329,806
Total	1,817,009
Due in one year or less, fair value	270,031
Due after one year through five years, fair value	1,009,579
Due after five years through ten years, fair value	203,358
Due after ten years, fair value	350,089
Total	1,833,057
Debt securities | Foreign corporate bonds and other debt securities
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost	463,244
Due after one year through five years, amortized cost	240,076
Due after five years through ten years, amortized cost	92,781
Due after ten years, amortized cost	20,320
Total	816,421
Due in one year or less, fair value	463,311
Due after one year through five years, fair value	240,935
Due after five years through ten years, fair value	92,929
Due after ten years, fair value	20,746
Total	¥ 817,921

Investments - Additional Inform

Investments - Additional Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2024	Mar. 31, 2023	Apr. 01, 2021
Gain (Loss) on Securities [Line Items]
Equity method Investments, carrying value			¥ 799,527	¥ 598,772
Japanese corporate bonds and other debt securities
Gain (Loss) on Securities [Line Items]
Credit losses on available-for-sale securities				0	¥ 14,000
Debt securities, available-for-sale, allowance for credit loss, period increase (decrease)	¥ 34,000	¥ 20,000
Held-to-maturity Securities | Japanese government bonds
Gain (Loss) on Securities [Line Items]
Credit losses on available-for-sale securities	¥ 0		¥ 0	0
Orient Corporation
Gain (Loss) on Securities [Line Items]
Percentage of proportionate share to the total outstanding common stock			49%
Joint Stock Commercial Bank Foreign Trade of Vietnam [Member]
Gain (Loss) on Securities [Line Items]
Percentage of proportionate share to the total outstanding common stock			15%
Mizuho Leasing Company LTD [Member]
Gain (Loss) on Securities [Line Items]
Percentage of proportionate share to the total outstanding common stock			23.54%
Matthew International Capital Management LLC [Member]
Gain (Loss) on Securities [Line Items]
Percentage of proportionate share to the total outstanding common stock			18.10%
Custody Bank of Japan Ltd [Member]
Gain (Loss) on Securities [Line Items]
Percentage of proportionate share to the total outstanding common stock			27%
Rakuten Securities, Inc [Member]
Gain (Loss) on Securities [Line Items]
Percentage of proportionate share to the total outstanding common stock			49%
Kisetsu Saison Finance (India) Private Ltd. [Member]
Gain (Loss) on Securities [Line Items]
Percentage of proportionate share to the total outstanding common stock			16.25%
Equity securities (marketable)
Gain (Loss) on Securities [Line Items]
Equity method Investments, carrying value			¥ 316,205	268,736
Equity method Investments, aggregated market values			¥ 642,663	¥ 503,171

Investments - Gross Unrealized

Investments - Gross Unrealized Losses and Fair Value of Available-for-Sale and Held-to-Maturity Securities, Aggregated by Length of Time that Individual Securities Have Been in a Continuous Unrealized Loss Position (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2024	Mar. 31, 2023
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		¥ 10,774,551	¥ 6,269,815
Less than 12 months Gross unrealized losses, available-for-sale securities		6,663	22,388
12 months or more Fair value, available-for-sale securities		2,953,626	3,293,501
12 months or more Gross unrealized losses, available-for-sale securities		31,779	49,029
Total Fair value, available-for-sale securities		13,728,177	9,563,316
Total Gross unrealized losses, available-for-sale securities		38,442	71,417
Debt securities | Japanese government bonds
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		9,019,722	3,706,134
Less than 12 months Gross unrealized losses, available-for-sale securities		2,448	11,369
12 months or more Fair value, available-for-sale securities		675,435	1,419,222
12 months or more Gross unrealized losses, available-for-sale securities		508	26,127
Total Fair value, available-for-sale securities		9,695,157	5,125,356
Total Gross unrealized losses, available-for-sale securities		2,956	37,496
Debt securities | Japanese local government bonds
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		108,071	146,484
Less than 12 months Gross unrealized losses, available-for-sale securities		369	1,596
12 months or more Fair value, available-for-sale securities		456,471	322,224
12 months or more Gross unrealized losses, available-for-sale securities		7,205	4,032
Total Fair value, available-for-sale securities		564,542	468,708
Total Gross unrealized losses, available-for-sale securities		7,574	5,628
Debt securities | U.S. Treasury bonds and federal agency securities
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		113,185	65,288
Less than 12 months Gross unrealized losses, available-for-sale securities		252	765
12 months or more Fair value, available-for-sale securities		0	293,149
12 months or more Gross unrealized losses, available-for-sale securities		0	6,524
Total Fair value, available-for-sale securities		113,185	358,437
Total Gross unrealized losses, available-for-sale securities		252	7,289
Debt securities | Other foreign government bonds
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		865,375	475,493
Less than 12 months Gross unrealized losses, available-for-sale securities		1,196	674
12 months or more Fair value, available-for-sale securities		107,238	250,130
12 months or more Gross unrealized losses, available-for-sale securities		559	1,587
Total Fair value, available-for-sale securities		972,613	725,623
Total Gross unrealized losses, available-for-sale securities		1,755	2,261
Debt securities | Agency mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities	[1]	130,779	142,776
Less than 12 months Gross unrealized losses, available-for-sale securities	[1]	1,125	2,361
12 months or more Fair value, available-for-sale securities	[1]	307,777	238,858
12 months or more Gross unrealized losses, available-for-sale securities	[1]	17,100	8,946
Total Fair value, available-for-sale securities	[1]	438,556	381,634
Total Gross unrealized losses, available-for-sale securities	[1]	18,225	11,307
Debt securities | Residential mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		645	16,230
Less than 12 months Gross unrealized losses, available-for-sale securities		0	265
12 months or more Fair value, available-for-sale securities		25,220	22,017
12 months or more Gross unrealized losses, available-for-sale securities		766	601
Total Fair value, available-for-sale securities		25,865	38,247
Total Gross unrealized losses, available-for-sale securities		767	866
Debt securities | Commercial mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		18,594	105,346
Less than 12 months Gross unrealized losses, available-for-sale securities		214	304
12 months or more Fair value, available-for-sale securities		138,724	43,653
12 months or more Gross unrealized losses, available-for-sale securities		576	147
Total Fair value, available-for-sale securities		157,318	148,999
Total Gross unrealized losses, available-for-sale securities		789	451
Debt securities | Japanese corporate bonds and other debt securities
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		314,933	1,177,725
Less than 12 months Gross unrealized losses, available-for-sale securities		893	3,775
12 months or more Fair value, available-for-sale securities		1,217,858	635,289
12 months or more Gross unrealized losses, available-for-sale securities		5,016	763
Total Fair value, available-for-sale securities		1,532,791	1,813,014
Total Gross unrealized losses, available-for-sale securities		5,909	4,538
Debt securities | Foreign corporate bonds and other debt securities
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		203,248	434,339
Less than 12 months Gross unrealized losses, available-for-sale securities		166	1,279
12 months or more Fair value, available-for-sale securities		24,902	68,959
12 months or more Gross unrealized losses, available-for-sale securities		48	302
Total Fair value, available-for-sale securities		228,150	503,298
Total Gross unrealized losses, available-for-sale securities		¥ 214	¥ 1,581
[1]Agency mortgage-backed securities presented in this line consist of Japanese agency mortgage-backed securities, of which the fair values were ¥381,634 million at March 31, 2023, and ¥438,556 million at March 31, 2024. All Japanese agency mortgage-backed securities are issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise.

Investments - Gross Unrealize_2

Investments - Gross Unrealized Losses and Fair Value of Available-for-Sale and Held-to-Maturity Securities, Aggregated by Length of Time that Individual Securities Have Been in a Continuous Unrealized Loss Position (Parenthetical) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2024	Mar. 31, 2023
Gain (Loss) on Securities [Line Items]
Fair value, available-for-sale securities		¥ 13,728,177	¥ 9,563,316
Debt securities | Agency mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Fair value, available-for-sale securities	[1]	438,556	381,634
Debt securities | Japanese agency mortgage-backed securities | Agency mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Fair value, available-for-sale securities		¥ 438,556	¥ 381,634
[1]Agency mortgage-backed securities presented in this line consist of Japanese agency mortgage-backed securities, of which the fair values were ¥381,634 million at March 31, 2023, and ¥438,556 million at March 31, 2024. All Japanese agency mortgage-backed securities are issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise.

Investments - Realized Gains an

Investments - Realized Gains and Losses on Sales of Available-for-Sale Securities (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Gross realized gains	¥ 34,287	¥ 22,962	¥ 12,540
Gross realized losses	(51,384)	(23,593)	(40,077)
Net realized gains (losses) on sales of available-for-sale securities	¥ (17,097)	¥ (631)	¥ (27,537)

Investments - Summary of Detail

Investments - Summary of Details of Net Gains and Losses on Equity Securities (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Gain (Loss) on Securities [Line Items]
Net gains (losses) recognized during the period on equity securities	¥ 1,010,288	¥ 135,601	¥ (60,563)
Less: Net gains (losses) recognized during the period on equity securities sold during the period	235,564	29,561	17,000
Unrealized gains (losses) recognized during the reporting period on equity securities still held at the reporting period	¥ 774,724	¥ 106,040	¥ (77,563)

Investments - Summary of Equity

Investments - Summary of Equity Securities Without Readily Determinable Fair Values (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Equity Securities without Readily Determinable Fair Value [Line Items]
Carrying amounts at the end of the period	¥ 357,938	¥ 207,743	¥ 207,407
Downward adjustments and impairments	11,002	5,345	6,519
Upward adjustments	¥ 13,764	¥ 13,015	¥ 11,623

Investments - Summary of Downwa

Investments - Summary of Downward Adjustments and Impairments and Upward Adjustments (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Equity Securities without Readily Determinable Fair Value [Line Items]
Downward adjustments and impairments	¥ 7,296	¥ 1,291	¥ 2,626
Upward adjustments	¥ 825	¥ 1,459	¥ 2,459

Investments - Summary of Compos

Investments - Summary of Composition of Other Investments (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023
Schedule of Investments [Line Items]
Equity method investments	¥ 799,527	¥ 598,772
Investments held by consolidated investment companies and other	84,969	68,429
Total	¥ 884,496	¥ 667,201

Loans - Additional Information

Loans - Additional Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net losses on sales of loans	¥ 43,457	¥ 13,436	¥ 3,080
Unearned Income And Deferred Loan Fees	¥ 268,000	¥ 238,000
Accounts Receivable, Noncurrent, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Accrued Investment Income Receivable	Accrued Investment Income Receivable
Accrued income
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accrued interest receivables	¥ 260,000	¥ 198,000
Impaired Financing Receivables with No Related Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans partially charged off	¥ 8,168	¥ 11,314

Loans - Credit Quality Informat

Loans - Credit Quality Information of Loans Based on MHFG Group's Internal Rating System (Detail) - JPY (¥) ¥ in Billions		Mar. 31, 2024	Mar. 31, 2023
Normal obligors | Domestic | Retail | Housing Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[1]	¥ 350	¥ 711
2022	[1]	391	570
2021	[1]	431	476
2020	[1]	342	468
2019	[1]	360	478
Prior to 2019	[1]	5,224	4,723
Revolving loan	[1],[2]	0	0
Total	[1]	7,098	7,426
Normal obligors | Domestic | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[1]	211	184
2022	[1]	71	87
2021	[1]	54	226
2020	[1]	100	80
2019	[1]	48	64
Prior to 2019	[1]	337	297
Revolving loan	[1],[2]	470	484
Total	[1]	1,291	1,422
Watch obligors | Domestic | Retail | Housing Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[1]	0	1
2022	[1]	0	2
2021	[1]	0	1
2020	[1]	0	2
2019	[1]	0	1
Prior to 2019	[1]	36	35
Revolving loan	[1],[2]	0	0
Total	[1]	37	42
Watch obligors | Domestic | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[1]	23	22
2022	[1]	6	6
2021	[1]	5	21
2020	[1]	10	5
2019	[1]	3	4
Prior to 2019	[1]	7	5
Revolving loan	[1],[2]	8	8
Total	[1]	62	71
Non Accrual Loans | Domestic | Retail | Housing Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[1]	0	8
2022	[1]	0	2
2021	[1]	0	2
2020	[1]	0	1
2019	[1]	1	1
Prior to 2019	[1]	33	25
Revolving loan	[1],[2]	0	0
Total	[1]	35	39
Non Accrual Loans | Domestic | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[1]	5	9
2022	[1]	2	4
2021	[1]	3	6
2020	[1]	6	2
2019	[1]	2	4
Prior to 2019	[1]	22	20
Revolving loan	[1],[2]	9	10
Total	[1]	49	55
Financing Receivables Not Impaired
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[3]	33,665	32,710
2022	[3]	13,575	11,611
2021	[3]	8,525	9,195
2020	[3]	6,374	7,416
2019	[3]	5,075	5,355
Prior to 2019	[3]	12,997	11,438
Revolving loan	[2],[3]	18,233	16,451
Total	[3]	98,445	94,176
Financing Receivables Not Impaired | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[1]	17,261	15,428
2022	[1]	6,882	7,142
2021	[1]	5,585	6,667
2020	[1]	5,155	5,242
2019	[1]	3,911	4,252
Prior to 2019	[1]	11,883	10,035
Revolving loan	[1],[2]	9,932	9,164
Total	[1]	60,608	57,930
Financing Receivables Not Impaired | Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[3]	16,403	17,282
2022	[3]	6,694	4,469
2021	[3]	2,941	2,528
2020	[3]	1,219	2,174
2019	[3]	1,164	1,103
Prior to 2019	[3]	1,114	1,403
Revolving loan	[2],[3]	8,302	7,287
Total	[3]	37,837	36,246
Financing Receivables Not Impaired | Normal obligors | Domestic | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[1]	1,858	1,217
2022	[1]	47	54
2021	[1]	48	90
2020	[1]	92	91
2019	[1]	66	75
Prior to 2019	[1]	321	328
Revolving loan	[1],[2]	3	1
Total	[1]	2,436	1,856
Financing Receivables Not Impaired | Normal obligors | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[1]	120	107
2022	[1]	103	17
2021	[1]	262	23
2020	[1]	2	134
2019	[1]	107	155
Prior to 2019	[1]	110	114
Revolving loan	[1],[2]	527	95
Total	[1]	1,231	645
Financing Receivables Not Impaired | Normal obligors | Domestic | Corporate | Large Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023		13,870	12,277
2022		5,879	5,993
2021		4,505	5,384
2020		4,328	3,994
2019		2,832	3,065
Prior to 2019		4,979	3,670
Revolving loan	[2]	7,847	7,517
Total		44,241	41,900
Financing Receivables Not Impaired | Normal obligors | Domestic | Corporate | Small And Medium Sized Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023		430	551
2022		251	301
2021		195	285
2020		150	248
2019		151	221
Prior to 2019		533	571
Revolving loan	[2]	494	531
Total		2,204	2,708
Financing Receivables Not Impaired | Normal obligors | Foreign | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[3]	319	160
2022	[3]	215	188
2021	[3]	117	7
2020	[3]	2	32
2019	[3]	4	5
Prior to 2019	[3]	0	2
Revolving loan	[2],[3]	29	83
Total	[3]	686	477
Financing Receivables Not Impaired | Normal obligors | Foreign | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[3]	1,674	1,536
2022	[3]	874	265
2021	[3]	193	169
2020	[3]	21	91
2019	[3]	2	19
Prior to 2019	[3]	7	4
Revolving loan	[2],[3]	448	404
Total	[3]	3,219	2,488
Financing Receivables Not Impaired | Normal obligors | Foreign | Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[3]	14,106	15,317
2022	[3]	5,488	3,891
2021	[3]	2,589	2,142
2020	[3]	1,028	1,954
2019	[3]	1,128	1,024
Prior to 2019	[3]	1,028	1,312
Revolving loan	[2],[3]	7,706	6,731
Total	[3]	33,073	32,371
Financing Receivables Not Impaired | Normal obligors | Foreign | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[3]	2	2
2022	[3]	1	1
2021	[3]	1	1
2020	[3]	1	1
2019	[3]	1	1
Prior to 2019	[3]	3	3
Revolving loan	[2],[3]	0	0
Total	[3]	10	9
Financing Receivables Not Impaired | Watch obligors | Domestic | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[1]	8	8
2022	[1]	2	2
2021	[1]	1	0
2020	[1]	0	0
2019	[1]	0	0
Prior to 2019	[1]	0	0
Revolving loan	[1],[2]	0	0
Total	[1]	12	10
Financing Receivables Not Impaired | Watch obligors | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[1]	0	0
2022	[1]	0	0
2021	[1]	0	0
2020	[1]	0	0
2019	[1]	0	0
Prior to 2019	[1]	0	0
Revolving loan	[1],[2]	0	0
Total	[1]	0	0
Financing Receivables Not Impaired | Watch obligors | Domestic | Corporate | Large Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023		186	109
2022		42	46
2021		37	50
2020		43	58
2019		184	59
Prior to 2019		49	33
Revolving loan	[2]	172	130
Total		713	485
Financing Receivables Not Impaired | Watch obligors | Domestic | Corporate | Small And Medium Sized Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023		35	45
2022		15	16
2021		10	26
2020		12	16
2019		15	18
Prior to 2019		30	28
Revolving loan	[2]	19	20
Total		135	169
Financing Receivables Not Impaired | Watch obligors | Foreign | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[3]	0	0
2022	[3]	0	0
2021	[3]	0	0
2020	[3]	0	0
2019	[3]	0	0
Prior to 2019	[3]	0	0
Revolving loan	[2],[3]	0	0
Total	[3]	0	0
Financing Receivables Not Impaired | Watch obligors | Foreign | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[3]	0	8
2022	[3]	6	4
2021	[3]	4	4
2020	[3]	0	5
2019	[3]	6	0
Prior to 2019	[3]	0	0
Revolving loan	[2],[3]	0	0
Total	[3]	16	21
Financing Receivables Not Impaired | Watch obligors | Foreign | Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[3]	243	228
2022	[3]	83	101
2021	[3]	35	192
2020	[3]	161	72
2019	[3]	22	43
Prior to 2019	[3]	57	50
Revolving loan	[2],[3]	105	58
Total	[3]	705	744
Financing Receivables Not Impaired | Watch obligors | Foreign | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[3]	0	0
2022	[3]	0	0
2021	[3]	0	0
2020	[3]	0	0
2019	[3]	0	0
Prior to 2019	[3]	0	0
Revolving loan	[2],[3]	0	0
Total	[3]	0	0
Financing Receivables Not Impaired | Non Accrual Loans | Domestic | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[1]	0	0
2022	[1]	0	0
2021	[1]	0	0
2020	[1]	0	0
2019	[1]	0	0
Prior to 2019	[1]	0	0
Revolving loan	[1],[2]	0	0
Total	[1]	0	0
Financing Receivables Not Impaired | Non Accrual Loans | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[1]	0	0
2022	[1]	0	0
2021	[1]	0	0
2020	[1]	0	0
2019	[1]	0	0
Prior to 2019	[1]	0	0
Revolving loan	[1],[2]	0	0
Total	[1]	0	0
Financing Receivables Not Impaired | Non Accrual Loans | Domestic | Corporate | Large Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023		157	153
2022		65	35
2021		26	61
2020		61	134
2019		134	99
Prior to 2019		167	159
Revolving loan	[2]	356	339
Total		967	980
Financing Receivables Not Impaired | Non Accrual Loans | Domestic | Corporate | Small And Medium Sized Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023		8	26
2022		7	7
2021		7	16
2020		8	9
2019		8	8
Prior to 2019		33	27
Revolving loan	[2]	26	29
Total		97	122
Financing Receivables Not Impaired | Non Accrual Loans | Foreign | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[3]	0	0
2022	[3]	0	0
2021	[3]	0	0
2020	[3]	0	1
2019	[3]	0	0
Prior to 2019	[3]	0	0
Revolving loan	[2],[3]	0	0
Total	[3]	0	1
Financing Receivables Not Impaired | Non Accrual Loans | Foreign | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[3]	0	0
2022	[3]	0	0
2021	[3]	0	0
2020	[3]	0	0
2019	[3]	0	0
Prior to 2019	[3]	0	0
Revolving loan	[2],[3]	0	0
Total	[3]	0	0
Financing Receivables Not Impaired | Non Accrual Loans | Foreign | Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[3]	60	31
2022	[3]	27	19
2021	[3]	2	13
2020	[3]	5	18
2019	[3]	2	11
Prior to 2019	[3]	19	32
Revolving loan	[2],[3]	13	11
Total	[3]	127	135
Financing Receivables Not Impaired | Non Accrual Loans | Foreign | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
2023	[3]	0	0
2022	[3]	0	0
2021	[3]	0	0
2020	[3]	0	0
2019	[3]	0	0
Prior to 2019	[3]	0	0
Revolving loan	[2],[3]	0	0
Total	[3]	¥ 0	¥ 0
[1]The primary component of the retail portfolio segment is housing loans to individuals which obligor category is classified based on past due status. The trigger to reclassify obligors from normal obligors to watch obligors excluding special attention obligors is when the past due status is more than 30 days.[2]There were no significant revolving line of credit arrangements that converted to term loans during the fiscal year ended March 31, 2023 and 2024.[3]Corporate of foreign included ¥184 billion and ¥176 billion of lease receivables that were receivables arising from direct financing leasing at March 31, 2023 and 2024, respectively.

Loans - Credit Quality Inform_2

Loans - Credit Quality Information of Loans Based on MHFG Group's Internal Rating System (Parenthetical) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2024	Mar. 31, 2023
Financing Receivables Impaired [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Direct Financing Lease, Lease Receivable	¥ 176	¥ 184

Loans - Allowance For Credit Lo

Loans - Allowance For Credit Losses Write off On Financing Receivables (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2024		Mar. 31, 2023	[1]	Mar. 31, 2022
Allowance For Credit Losses Write off On Financing Receivables [Line Items]
2023		¥ 7,000
2022		18,000
2021		3,000
2020		2,000
2019		2,000
Prior to 2019		10,000
Revolving Loans		4,000
Total		46,323	[1]	¥ 227,450		¥ 59,840
Geographic Distribution, Domestic [Member]
Allowance For Credit Losses Write off On Financing Receivables [Line Items]
2023		6,000
2022		16,000
2021		3,000
2020		0
2019		2,000
Prior to 2019		4,000
Revolving Loans		4,000
Total		37,000
Geographic Distribution, Domestic [Member] | Corporate Rating [Member] | Large Companies [Member]
Allowance For Credit Losses Write off On Financing Receivables [Line Items]
2023		5,000
2022		13,000
2021		3,000
2020		0
2019		2,000
Prior to 2019		1,000
Revolving Loans		2,000
Total		27,000
Geographic Distribution, Domestic [Member] | Corporate Rating [Member] | Small And Medium Sized Companies [Member]
Allowance For Credit Losses Write off On Financing Receivables [Line Items]
2023		1,000
2022		2,000
2021		0
2020		0
2019		0
Prior to 2019		0
Revolving Loans		2,000
Total		5,000
Geographic Distribution, Domestic [Member] | Retail Rating [Member] | Housing Loan [Member]
Allowance For Credit Losses Write off On Financing Receivables [Line Items]
2023		0
2022		0
2021		0
2020		0
2019		0
Prior to 2019		2,000
Revolving Loans		0
Total		2,000
Geographic Distribution, Domestic [Member] | Retail Rating [Member] | Other [Member]
Allowance For Credit Losses Write off On Financing Receivables [Line Items]
2023		1,000
2022		1,000
2021		0
2020		0
2019		0
Prior to 2019		1,000
Revolving Loans		0
Total		3,000
Geographic Distribution, Foreign [Member]
Allowance For Credit Losses Write off On Financing Receivables [Line Items]
2023	[2]	0
2022	[2]	1,000
2021	[2]	1,000
2020	[2]	2,000
2019	[2]	0
Prior to 2019	[2]	6,000
Revolving Loans	[2]	0
Total	[2]	¥ 9,505	[1]	¥ 68,772		¥ 23,144
[1]Charge-offs decreased from ¥227,450 million for the fiscal year ended March 31, 2023 to ¥46,323 million for the fiscal year ended March 31, 2024. The decrease was due mainly to a charge-off related to a debt waiver to a domestic corporate borrower which was recognized in the fiscal year ended March 31, 2023.[2]The majority of total foreign consist of corporate.

Loans - Impaired Loans Informat

Loans - Impaired Loans Information (Detail) - JPY (¥) ¥ in Billions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans with an allowance	¥ 1,212	¥ 1,255
Nonaccrual loans without an allowance	64	77
Total nonaccrual loans	1,276	1,332
Interest income recognized	20	23
Domestic
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans with an allowance	1,088	1,123
Nonaccrual loans without an allowance	61	73
Total nonaccrual loans	1,149	1,196
Interest income recognized	16	19
Domestic | Retail | Housing Loan
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans with an allowance	20	22
Nonaccrual loans without an allowance	15	17
Total nonaccrual loans	35	39
Interest income recognized	1	1
Domestic | Retail | Other
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans with an allowance	31	37
Nonaccrual loans without an allowance	18	18
Total nonaccrual loans	49	55
Interest income recognized	1	1
Domestic | Large companies | Corporate
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans with an allowance	950	961
Nonaccrual loans without an allowance	17	19
Total nonaccrual loans	967	980
Interest income recognized	13	16
Domestic | Small and medium sized companies | Corporate
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans with an allowance	86	103
Nonaccrual loans without an allowance	12	19
Total nonaccrual loans	97	122
Interest income recognized	1	1
Foreign
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans with an allowance	124	132
Nonaccrual loans without an allowance	3	4
Total nonaccrual loans	127	136
Interest income recognized	¥ 4	¥ 4

Loans - Troubled Debt Restructu

Loans - Troubled Debt Restructurings Entered Modified Periods by Type of Concession Granted (Detail) ¥ in Billions	12 Months Ended
	Mar. 31, 2023 JPY (¥)
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	¥ 0
Loan forgiveness or debt to equity swaps charge-offs	141
Interest rate reduction and/or postponement of principal and/or interest	791
Domestic
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	0
Loan forgiveness or debt to equity swaps charge-offs	141
Interest rate reduction and/or postponement of principal and/or interest	725
Domestic | Housing Loan | Retail
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	0
Loan forgiveness or debt to equity swaps charge-offs	0
Interest rate reduction and/or postponement of principal and/or interest	5
Domestic | Other | Retail
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	0
Loan forgiveness or debt to equity swaps charge-offs	0
Interest rate reduction and/or postponement of principal and/or interest	19
Domestic | Large Companies | Corporate
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	0
Loan forgiveness or debt to equity swaps charge-offs	141
Interest rate reduction and/or postponement of principal and/or interest	595
Domestic | Small And Medium Sized Companies | Corporate
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	0
Loan forgiveness or debt to equity swaps charge-offs	0
Interest rate reduction and/or postponement of principal and/or interest	106
Foreign
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	0
Loan forgiveness or debt to equity swaps charge-offs	0
Interest rate reduction and/or postponement of principal and/or interest	¥ 66

Loans - Troubled Debt Restruc_2

Loans - Troubled Debt Restructurings On Financing Receivables (Detail) ¥ in Billions	12 Months Ended
	Mar. 31, 2024 JPY (¥)
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	¥ 298
Domestic
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	278
Domestic | Corporate | Large companies
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	237
Domestic | Corporate | Small and medium-sized companies
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	35
Domestic | Retail | Housing Loan
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Domestic | Retail | Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	5
Foreign
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	20
Term Extension
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	280
Term Extension | Domestic
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	265
Term Extension | Domestic | Corporate | Large companies
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	227
Term Extension | Domestic | Corporate | Small and medium-sized companies
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	34
Term Extension | Domestic | Retail | Housing Loan
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Term Extension | Domestic | Retail | Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	4
Term Extension | Foreign
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	15
Interest rate reduction
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	5
Interest rate reduction | Domestic
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Interest rate reduction | Domestic | Corporate | Large companies
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Interest rate reduction | Domestic | Corporate | Small and medium-sized companies
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Interest rate reduction | Domestic | Retail | Housing Loan
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Interest rate reduction | Domestic | Retail | Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Interest rate reduction | Foreign
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	5
Term Extension And Interest Rate Reduction
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	6
Term Extension And Interest Rate Reduction | Domestic
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	6
Term Extension And Interest Rate Reduction | Domestic | Corporate | Large companies
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	4
Term Extension And Interest Rate Reduction | Domestic | Corporate | Small and medium-sized companies
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	2
Term Extension And Interest Rate Reduction | Domestic | Retail | Housing Loan
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Term Extension And Interest Rate Reduction | Domestic | Retail | Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Term Extension And Interest Rate Reduction | Foreign
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	1
Principal Forgiveness
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Principal Forgiveness | Domestic
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Principal Forgiveness | Domestic | Corporate | Large companies
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Principal Forgiveness | Domestic | Corporate | Small and medium-sized companies
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Principal Forgiveness | Domestic | Retail | Housing Loan
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Principal Forgiveness | Domestic | Retail | Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Principal Forgiveness | Foreign
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	6
Other | Domestic
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	6
Other | Domestic | Corporate | Large companies
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	6
Other | Domestic | Corporate | Small and medium-sized companies
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Other | Domestic | Retail | Housing Loan
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Other | Domestic | Retail | Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	0
Other | Foreign
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modified in Period, Amount	¥ 0

Loans - Troubled Debt Restruc_3

Loans - Troubled Debt Restructurings On Financing Receivables (Parenthetical) (Detail)	12 Months Ended
	Mar. 31, 2024
Financing Receivable, Modifications [Line Items]
Financing receivable modified weighted average term increase from modification	12 months 3 days
Financing Receivable, Modified, Weighted Average Interest Rate Decrease from Modification	0.60%

Loans - Delinquent Status of Mo

Loans - Delinquent Status of Modified Loans to Borrowers Experiencing Financial Difficulty (Detail) ¥ in Billions	Mar. 31, 2024 JPY (¥)
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	¥ 298
Domestic | Corporate | Large companies
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	237
Domestic | Corporate | Small and medium-sized companies
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	35
Domestic | Retail
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	278
Domestic | Retail | Housing Loan
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
Domestic | Retail | Other
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	5
Foreign
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	20	[1]
30-59 Days Past Due
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
30-59 Days Past Due | Domestic | Corporate | Large companies
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
30-59 Days Past Due | Domestic | Corporate | Small and medium-sized companies
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
30-59 Days Past Due | Domestic | Retail
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
30-59 Days Past Due | Domestic | Retail | Housing Loan
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
30-59 Days Past Due | Domestic | Retail | Other
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
30-59 Days Past Due | Foreign
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0	[1]
60-89 Days Past Due
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
60-89 Days Past Due | Domestic | Corporate | Large companies
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
60-89 Days Past Due | Domestic | Corporate | Small and medium-sized companies
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
60-89 Days Past Due | Domestic | Retail
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
60-89 Days Past Due | Domestic | Retail | Housing Loan
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
60-89 Days Past Due | Domestic | Retail | Other
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
60-89 Days Past Due | Foreign
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0	[1]
90 Days or More Past Due
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	4
90 Days or More Past Due | Domestic | Corporate | Large companies
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	4
90 Days or More Past Due | Domestic | Corporate | Small and medium-sized companies
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
90 Days or More Past Due | Domestic | Retail
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	4
90 Days or More Past Due | Domestic | Retail | Housing Loan
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
90 Days or More Past Due | Domestic | Retail | Other
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
90 Days or More Past Due | Foreign
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0	[1]
Total Past Due
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	5
Total Past Due | Domestic | Corporate | Large companies
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	4
Total Past Due | Domestic | Corporate | Small and medium-sized companies
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
Total Past Due | Domestic | Retail
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	5
Total Past Due | Domestic | Retail | Housing Loan
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
Total Past Due | Domestic | Retail | Other
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
Total Past Due | Foreign
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0	[1]
Current
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	293
Current | Domestic | Corporate | Large companies
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	234
Current | Domestic | Corporate | Small and medium-sized companies
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	35
Current | Domestic | Retail
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	273
Current | Domestic | Retail | Housing Loan
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	0
Current | Domestic | Retail | Other
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	5
Current | Foreign
Financing Receivable, Modified, Past Due [Line Items]
Financing Receivable, Modified in Period, Amount	¥ 20	[1]
[1]The majority of total foreign consist of corporate.

Loans - Payment Defaults Occurr

Loans - Payment Defaults Occurred During Periods with Respect to Loans Modified as Troubled Debt Restructurings within Previous twelve Months (Detail) ¥ in Billions	12 Months Ended
	Mar. 31, 2023 JPY (¥)
Financing Receivable, Modifications [Line Items]
Recorded investment	¥ 108
Domestic
Financing Receivable, Modifications [Line Items]
Recorded investment	98
Domestic | Corporate | Large companies
Financing Receivable, Modifications [Line Items]
Recorded investment	95
Domestic | Corporate | Small and medium sized companies
Financing Receivable, Modifications [Line Items]
Recorded investment	1
Domestic | Retail | Housing Loan
Financing Receivable, Modifications [Line Items]
Recorded investment	1
Domestic | Retail | Other
Financing Receivable, Modifications [Line Items]
Recorded investment	1
Foreign
Financing Receivable, Modifications [Line Items]
Recorded investment	¥ 10

Loans - Age Analysis of Past Du

Loans - Age Analysis of Past Due Loans (Detail) - JPY (¥) ¥ in Billions		Mar. 31, 2024	Mar. 31, 2023
30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		¥ 18	¥ 18
30-59 Days Past Due | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		18	18
30-59 Days Past Due | Domestic | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		0	0
30-59 Days Past Due | Domestic | Corporate | Large companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		1	0
30-59 Days Past Due | Domestic | Corporate | Small and medium sized companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		0	0
30-59 Days Past Due | Domestic | Retail | Housing Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		12	14
30-59 Days Past Due | Domestic | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		5	4
30-59 Days Past Due | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		0	0
30-59 Days Past Due | Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	[1]	0	0
60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		9	12
60-89 Days Past Due | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		9	12
60-89 Days Past Due | Domestic | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		0	0
60-89 Days Past Due | Domestic | Corporate | Large companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		0	3
60-89 Days Past Due | Domestic | Corporate | Small and medium sized companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		1	0
60-89 Days Past Due | Domestic | Retail | Housing Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		7	8
60-89 Days Past Due | Domestic | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		1	1
60-89 Days Past Due | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		0	0
60-89 Days Past Due | Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	[1]	0	0
90 Days or More Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		82	83
90 Days or More Past Due | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		62	60
90 Days or More Past Due | Domestic | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		0	0
90 Days or More Past Due | Domestic | Corporate | Large companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		35	28
90 Days or More Past Due | Domestic | Corporate | Small and medium sized companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		5	9
90 Days or More Past Due | Domestic | Retail | Housing Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		12	13
90 Days or More Past Due | Domestic | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		10	10
90 Days or More Past Due | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		0	0
90 Days or More Past Due | Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	[1]	20	23
Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		109	113
Total Past Due | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		89	90
Total Past Due | Domestic | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		0	0
Total Past Due | Domestic | Corporate | Large companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		37	31
Total Past Due | Domestic | Corporate | Small and medium sized companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		6	9
Total Past Due | Domestic | Retail | Housing Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		31	35
Total Past Due | Domestic | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		16	15
Total Past Due | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		0	0
Total Past Due | Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	[1]	20	23
Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		98,335	94,063
Current | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		60,519	57,840
Current | Domestic | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		2,447	1,866
Current | Domestic | Corporate | Large companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		45,884	43,334
Current | Domestic | Corporate | Small and medium sized companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		2,431	2,990
Current | Domestic | Retail | Housing Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		7,139	7,472
Current | Domestic | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		1,387	1,533
Current | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		1,231	645
Current | Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	[1]	37,817	36,223
Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		98,445	94,176
Total | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		60,608	57,930
Total | Domestic | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		2,447	1,866
Total | Domestic | Corporate | Large companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		45,921	43,365
Total | Domestic | Corporate | Small and medium sized companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		2,436	2,999
Total | Domestic | Retail | Housing Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		7,170	7,507
Total | Domestic | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		1,403	1,548
Total | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross		1,231	645
Total | Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	[1]	¥ 37,837	¥ 36,246
[1]The majority of total foreign consist of corporate.

Allowance for Credit Losses o_3

Allowance for Credit Losses on Loans (Changes in Allowance for Loan Losses, Allowance for Loan Losses and Loans Outstanding Disaggregated on Basis of Impairment Method, by Portfolio Segment) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2024		Mar. 31, 2023		Mar. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of fiscal year		¥ 700,959		¥ 809,817		¥ 650,849
Provision (credit) for credit losses on loans		52,827		90,848		187,599
Charge-offs		(46,323)	[1]	(227,450)	[1]	(59,840)
Recoveries		11,948		10,476		18,754
Net charge-offs		(34,376)		(216,974)		(41,086)
Others	[2]	30,660		17,268		12,455
Balance at end of fiscal year		750,071		700,959		809,817
Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs		(37,000)
Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of fiscal year	[3]	130,594		134,397		85,567
Provision (credit) for credit losses on loans	[3]	(26,061)		44,287		49,729
Charge-offs	[3]	(9,505)	[1]	(68,772)	[1]	(23,144)
Recoveries	[3]	4,561		3,414		9,832
Net charge-offs	[3]	(4,945)		(65,358)		(13,312)
Others	[2],[3]	30,660		17,268		12,413
Balance at end of fiscal year	[3]	130,249		130,594		134,397
Corporate | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of fiscal year		505,901		601,506		481,420
Provision (credit) for credit losses on loans		83,702		51,551		144,998
Charge-offs		(31,936)	[1]	(153,014)	[1]	(32,530)
Recoveries		6,049		5,858		7,618
Net charge-offs		(25,887)		(147,156)		(24,912)
Others	[2]	0		0		0
Balance at end of fiscal year		563,716		505,901		601,506
Retail | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of fiscal year		63,541		73,414		83,171
Provision (credit) for credit losses on loans		(4,208)		(5,413)		(6,895)
Charge-offs		(4,882)	[1]	(5,664)	[1]	(4,166)
Recoveries		1,338		1,204		1,304
Net charge-offs		(3,544)		(4,460)		(2,862)
Others	[2]	0		0		0
Balance at end of fiscal year		55,790		63,541		73,414
Sovereign | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of fiscal year		53		62		68
Provision (credit) for credit losses on loans		(9)		(9)		(6)
Charge-offs		0	[1]	0	[1]	0
Recoveries		0		0		0
Net charge-offs		0		0		0
Others	[2]	0		0		0
Balance at end of fiscal year		44		53		62
Banks and other financial institutions | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of fiscal year		870		438		623
Provision (credit) for credit losses on loans		(597)		432		(227)
Charge-offs		0	[1]	0	[1]	0
Recoveries		0		0		0
Net charge-offs		0		0		0
Others	[2]	0		0		42
Balance at end of fiscal year		¥ 273		¥ 870		¥ 438
[1]Charge-offs decreased from ¥227,450 million for the fiscal year ended March 31, 2023 to ¥46,323 million for the fiscal year ended March 31, 2024. The decrease was due mainly to a charge-off related to a debt waiver to a domestic corporate borrower which was recognized in the fiscal year ended March 31, 2023.[2]Others includes primarily foreign exchange translation.[3]The majority of total foreign consist of corporate.

Allowance for Credit Losses o_4

Allowance for Credit Losses on Loans (Changes in Allowance for Loan Losses, Allowance for Loan Losses and Loans Outstanding Disaggregated on Basis of Impairment Method, by Portfolio Segment) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024		Mar. 31, 2023		Mar. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-Offs	¥ 46,323	[1]	¥ 227,450	[1]	¥ 59,840
Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-Offs	¥ 46,323
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-Offs			¥ 227,450
[1]Charge-offs decreased from ¥227,450 million for the fiscal year ended March 31, 2023 to ¥46,323 million for the fiscal year ended March 31, 2024. The decrease was due mainly to a charge-off related to a debt waiver to a domestic corporate borrower which was recognized in the fiscal year ended March 31, 2023.

Premises and equipment-Summary

Premises and equipment-Summary of Premises and Equipment (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	¥ 3,373,076	¥ 3,275,098
Less: Accumulated depreciation and amortization	1,658,590	1,621,210
Premises and equipment—net	1,714,485	1,653,888
Land
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	577,026	577,755
Buildings
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	684,476	703,655
Equipment and furniture
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	393,379	378,015
Leasehold improvements
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	217,762	204,835
Construction in Progress
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	47,787	44,393
Software
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	¥ 1,452,645	¥ 1,366,445

Premises and Equipment - Additi

Premises and Equipment - Additional Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Property, Plant and Equipment [Line Items]
Impairment losses			¥ 13,500
Depreciation and amortization	¥ 214,157	¥ 231,291	220,436
General and Administrative expenses
Property, Plant and Equipment [Line Items]
Impairment losses			433
Occupancy expenses
Property, Plant and Equipment [Line Items]
Impairment losses			13,067
Entity-wide assets
Property, Plant and Equipment [Line Items]
Impairment losses on real estate			¥ 12,976

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets (Changes in Goodwill) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Goodwill [Line Items]
Balance at beginning of fiscal year		¥ 92,928	¥ 92,695	¥ 92,695
Goodwill acquired	[1]	66,980	233	0
Foreign exchange translation		4,550	0	0
Balance at end of fiscal year		164,458	92,928	92,695
Gross amount of goodwill	[2]	235,563	163,209	161,993
Accumulated impairment losses		¥ 71,105	¥ 70,281	¥ 69,298
[1]For the fiscal year ended March 31, 2024, Goodwill acquired is entirely related to the acquisition of Greenhill & Co., Inc.[2]Goodwill is recorded at a designated reporting unit level for the purpose of assessing impairment. Goodwill is not allocated to the reportable segments in Note 30 “Business segment information.”

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets (Gross Carrying Amount, Accumulated Amortization and Net Carrying Amount of Intangible Assets) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2024	Mar. 31, 2023
Intangible Assets by Major Class [Line Items]
Gross carrying amount		¥ 143,562	¥ 133,007
Gross carrying amount		7,293	7,859
Gross carrying amount		150,855	140,866
Accumulated amortization		105,871	96,185
Net carrying amount		37,690	36,822
Net carrying amount		7,293	7,859
Net carrying amount		44,984	44,681
Customer relationships
Intangible Assets by Major Class [Line Items]
Gross carrying amount	[1]	135,866	130,124
Accumulated amortization	[1]	102,231	94,777
Net carrying amount	[1]	33,636	35,347
Other
Intangible Assets by Major Class [Line Items]
Gross carrying amount		7,696	2,883
Accumulated amortization		3,641	1,408
Net carrying amount		¥ 4,055	¥ 1,475
[1]Customer relationships were mainly acquired in connection with the merger of MHSC and Shinko on May 7, 2009 and the integration among asset management companies on October 1, 2016. See Note 1 “Basis of presentation and summary of significant accounting policies” for further information.

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Additional Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Goodwill and Intangible Assets Disclosure [Line Items]
Intangible assets amortization expense recognized	¥ 8,557	¥ 7,706	¥ 7,961

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets (Estimated Aggregate Amortization Expense in Respect of Intangible Assets) (Detail) ¥ in Millions	Mar. 31, 2024 JPY (¥)
Finite-Lived Intangible Assets [Line Items]
2025	¥ 8,825
2026	7,211
2027	6,492
2028	3,526
2029	¥ 3,098

Pledged Assets and Collateral_2

Pledged Assets and Collateral (Amounts Pledged as Collateral for Borrowings and for Other Purposes) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2024	Mar. 31, 2023
Financial Instruments Owned and Pledged as Collateral [Line Items]
Interest-bearing deposits in other banks	¥ 94	¥ 92
Trading account assets	12,331	7,830
Investments	15,081	12,452
Other assets	2,699	2,059
Total	38,904	31,148
Asset Pledged as Collateral without Right [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Loans	¥ 8,699	¥ 8,715

Pledged Assets and Collateral_3

Pledged Assets and Collateral (Associated Liabilities Collateralized by Pledged Assets) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2024	Mar. 31, 2023
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Deposits	¥ 217	¥ 988
Payables under repurchase agreements	17,553	10,542
Payables under securities lending transactions	689	721
Other short-term borrowings	1,803	1,003
Long-term debt	2,490	2,173
Total	¥ 22,752	¥ 15,427

Pledged Assets and Collateral -

Pledged Assets and Collateral - Additional Information (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2024	Mar. 31, 2023
Assets that Continue to be Recognized, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]
Reserve funds maintained with the BOJ	¥ 70,593	¥ 64,993
Reserve funds requires to be maintained by MHFG Group	1,734	1,701
Fair value collateral received that can be sold or repledged	25,466	15,529
Fair value collateral received that can be sold or repledged, value of collateral sold or repledged	¥ 22,812	¥ 13,379

Deposits (Balance and Remaining

Deposits (Balance and Remaining Maturities of Time Deposits and Certificates of Deposit Issued by Domestic and Foreign Offices) (Detail) ¥ in Millions	Mar. 31, 2024 JPY (¥)
Deposits From Banking Clients [Line Items]
Total	¥ 60,090,586
Bank Time Deposits Liabilities Domestic
Deposits From Banking Clients [Line Items]
Due in one year or less	21,154,572
Due after one year through two years	1,121,763
Due after two years through three years	917,388
Due after three years through four years	273,448
Due after four years through five years	316,649
Due after five years	300,193
Total	24,084,013
Certificates Of Deposit Liabilities Domestic
Deposits From Banking Clients [Line Items]
Due in one year or less	2,339,785
Due after one year through two years	121,500
Due after two years through three years	0
Due after three years through four years	0
Due after four years through five years	0
Due after five years	0
Total	2,461,285
Bank Time Deposits Liabilities Foreign
Deposits From Banking Clients [Line Items]
Due in one year or less	24,366,453
Due after one year through two years	34,381
Due after two years through three years	14,995
Due after three years through four years	211
Due after four years through five years	1
Due after five years	0
Total	24,416,041
Certificates Of Deposit Liabilities Foreign
Deposits From Banking Clients [Line Items]
Due in one year or less	8,783,902
Due after one year through two years	98,670
Due after two years through three years	172,673
Due after three years through four years	74,003
Due after four years through five years	0
Due after five years	0
Total	9,129,247
Time deposits
Deposits From Banking Clients [Line Items]
Total	48,500,053
Certificates of deposit
Deposits From Banking Clients [Line Items]
Total	11,590,532
Domestic
Deposits From Banking Clients [Line Items]
Due in one year or less	23,494,357
Due after one year through two years	1,243,263
Due after two years through three years	917,388
Due after three years through four years	273,448
Due after four years through five years	316,649
Due after five years	300,193
Total	26,545,298
Foreign
Deposits From Banking Clients [Line Items]
Due in one year or less	33,150,355
Due after one year through two years	133,051
Due after two years through three years	187,667
Due after three years through four years	74,214
Due after four years through five years	1
Due after five years	0
Total	¥ 33,545,288

Deposits (Estimated amounts Of

Deposits (Estimated amounts Of Uninsured Time Deposits And Certificates Of Deposit Issued By Domestic And Foreign Offices) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2024	Mar. 31, 2023
Domestic
Deposits From Banking Clients [Line Items]
Domestic deposit	¥ 19,492	¥ 20,209
Foreign
Deposits From Banking Clients [Line Items]
Domestic deposit	33,545	30,059
Time deposits | Domestic
Deposits From Banking Clients [Line Items]
Domestic deposit	17,031	13,977
Time deposits | Foreign
Deposits From Banking Clients [Line Items]
Domestic deposit	24,416	22,503
Certificates of deposit | Domestic
Deposits From Banking Clients [Line Items]
Domestic deposit	2,461	6,232
Certificates of deposit | Foreign
Deposits From Banking Clients [Line Items]
Domestic deposit	¥ 9,129	¥ 7,556

Deposits - Additional Informati

Deposits - Additional Information (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2024	Mar. 31, 2023
Deposits From Banking Clients [Line Items]
Aggregate amount of demand deposits in overdraft status that have been reclassified as loan balances	¥ 516	¥ 586

Short-Term Borrowings and Lon_3

Short-Term Borrowings and Long-Term Debt (Details of Other Short-Term Borrowings) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2024	Mar. 31, 2023
Short-term Debt [Line Items]
Borrowings from the Bank of Japan		¥ 1,588,529	¥ 876,036
Other		324,659	262,040
Total		3,644,912	3,397,329
Mizuho Financial Group, Inc.
Short-term Debt [Line Items]
Commercial paper and short-term notes issued	[1],[2]	1,641,988	2,218,111
Consolidated VIEs
Short-term Debt [Line Items]
Commercial paper and short-term notes issued	[1]	89,736	41,142
Total		¥ 247,180	¥ 187,852
[1]Short-term notes are issued under the laws of Japan in the form of commercial paper.[2]The amounts of commercial paper and short-term notes issued by MHFG’s subsidiaries were ¥1,782,111 million and ¥436,000 million, respectively, at March 31, 2023, and ¥1,165,988 million and ¥476,000 million, respectively, at March 31, 2024.

Short-Term Borrowings and Lon_4

Short-Term Borrowings and Long-Term Debt (Details of Other Short-Term Borrowings) (Parenthetical) (Detail) - Mizuho Financial Group, Inc. - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023
Short-term Debt [Line Items]
Commercial paper	¥ 1,165,988	¥ 1,782,111
Short-term notes	¥ 476,000	¥ 436,000

Short-Term Borrowings and Lon_5

Short-Term Borrowings and Long-Term Debt (Long-Term Debt with Original Maturities of More than One Year) (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023
Debt Instrument [Line Items]
Obligations under finance leases	¥ 21,185	¥ 6,863
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Obligations under finance leases	Obligations under finance leases
Loan participation borrowings	¥ 258,201	¥ 245,176
Senior borrowings and bonds	12,556,710	11,245,475
Subordinated borrowings and bonds	3,441,235	3,395,509
Total	¥ 16,277,331	¥ 14,893,023

Short-Term Borrowings and Lon_6

Short-Term Borrowings and Long-Term Debt (Interest Rates and Maturities of Senior Borrowings and Bonds, and Subordinated Borrowings and Bonds) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Debt Instrument [Line Items]
Borrowings and bonds		¥ 15,997,945	¥ 14,640,984
Senior borrowings and bonds
Debt Instrument [Line Items]
Borrowings and bonds		12,556,710	11,245,475
Senior borrowings and bonds | Fixed Rate | Denominated in Japanese yen
Debt Instrument [Line Items]
Borrowings and bonds		3,313,535	2,819,085
Senior borrowings and bonds | Fixed Rate | Denominated in U.S. dollars
Debt Instrument [Line Items]
Borrowings and bonds		4,333,084	3,692,271
Senior borrowings and bonds | Fixed Rate | Denominated in other currencies
Debt Instrument [Line Items]
Borrowings and bonds		2,361,302	1,948,714
Senior borrowings and bonds | Floating Rate | Denominated in Japanese yen
Debt Instrument [Line Items]
Borrowings and bonds		509,799	569,173
Senior borrowings and bonds | Floating Rate | Denominated in U.S. dollars
Debt Instrument [Line Items]
Borrowings and bonds		1,993,666	2,058,714
Senior borrowings and bonds | Floating Rate | Denominated in other currencies
Debt Instrument [Line Items]
Borrowings and bonds		45,325	157,518
Subordinated borrowings and bonds
Debt Instrument [Line Items]
Borrowings and bonds		3,441,235	3,395,509
Subordinated borrowings and bonds | Fixed Rate | Denominated in Japanese yen
Debt Instrument [Line Items]
Borrowings and bonds		3,176,285	2,961,504
Subordinated borrowings and bonds | Fixed Rate | Denominated in U.S. dollars
Debt Instrument [Line Items]
Borrowings and bonds		¥ 264,950	¥ 434,005
Minimum [Member] | Senior borrowings and bonds | Fixed Rate | Denominated in Japanese yen
Debt Instrument [Line Items]
Interest rates	[1]	0%
Maturities, Start	[2]	2024-04
Minimum [Member] | Senior borrowings and bonds | Fixed Rate | Denominated in U.S. dollars
Debt Instrument [Line Items]
Interest rates	[1]	0%
Maturities, Start	[2]	2024-04
Minimum [Member] | Senior borrowings and bonds | Fixed Rate | Denominated in other currencies
Debt Instrument [Line Items]
Interest rates	[1]	0%
Maturities, Start	[2]	2024-04
Minimum [Member] | Senior borrowings and bonds | Floating Rate | Denominated in Japanese yen
Debt Instrument [Line Items]
Interest rates	[1]	0%
Maturities, Start	[2]	2024-04
Minimum [Member] | Senior borrowings and bonds | Floating Rate | Denominated in U.S. dollars
Debt Instrument [Line Items]
Interest rates	[1]	0.10%
Maturities, Start	[2]	2024-04
Minimum [Member] | Senior borrowings and bonds | Floating Rate | Denominated in other currencies
Debt Instrument [Line Items]
Interest rates	[1]	0%
Maturities, Start	[2]	2024-04
Minimum [Member] | Subordinated borrowings and bonds | Fixed Rate | Denominated in Japanese yen
Debt Instrument [Line Items]
Interest rates	[1]	0.39%
Maturities, Start	[2]	2024-06
Minimum [Member] | Subordinated borrowings and bonds | Fixed Rate | Denominated in U.S. dollars
Debt Instrument [Line Items]
Interest rates	[1]	2.56%
Maturities, Start	[2]	2025-10
Maximum [Member] | Senior borrowings and bonds | Fixed Rate | Denominated in Japanese yen
Debt Instrument [Line Items]
Interest rates	[1]	6.20%
Maturities, End	[2]	2051-06
Maximum [Member] | Senior borrowings and bonds | Fixed Rate | Denominated in U.S. dollars
Debt Instrument [Line Items]
Interest rates	[1]	6%
Maturities, End	[2]	2048-03
Maximum [Member] | Senior borrowings and bonds | Fixed Rate | Denominated in other currencies
Debt Instrument [Line Items]
Interest rates	[1]	6.02%
Maturities, End	[2]	2041-05
Maximum [Member] | Senior borrowings and bonds | Floating Rate | Denominated in Japanese yen
Debt Instrument [Line Items]
Interest rates	[1]	25%
Maturities, End	[2]	2081-09
Maximum [Member] | Senior borrowings and bonds | Floating Rate | Denominated in U.S. dollars
Debt Instrument [Line Items]
Interest rates	[1]	17.20%
Maturities, End	[2]	2068-04
Maximum [Member] | Senior borrowings and bonds | Floating Rate | Denominated in other currencies
Debt Instrument [Line Items]
Interest rates	[1]	8%
Maturities, End	[2]	2041-09
Maximum [Member] | Subordinated borrowings and bonds | Fixed Rate | Denominated in Japanese yen
Debt Instrument [Line Items]
Interest rates	[1]	4.26%
Maximum [Member] | Subordinated borrowings and bonds | Fixed Rate | Denominated in U.S. dollars
Debt Instrument [Line Items]
Interest rates	[1]	4.35%
Maturities, End	[2]	2031-09
[1]The interest rates disclosed reflect the range of contractual rates in effect at March 31, 2024.[2]Maturity information disclosed is the range of maturities at March 31, 2024.

Short-Term Borrowings and Lon_7

Short-Term Borrowings and Long-Term Debt (Contractual Maturities of Long-Term Debt) (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023
Debt Instrument [Line Items]
2025	¥ 3,499,569
2026	926,755
2027	1,692,064
2028	1,363,547
2029	986,587
2030 and thereafter	7,808,809
Total	¥ 16,277,331	¥ 14,893,023

Other Assets and Liabilities (D

Other Assets and Liabilities (Details of Other Assets and Liabilities) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2024	Mar. 31, 2023
Other assets:
Receivables from brokers, dealers and customers for securities transactions		¥ 2,278,334	¥ 4,469,286
Other		571,349	468,344
Collateral pledged for derivative transactions		1,406,369	988,881
Margins provided for futures contracts		264,473	183,747
Other		1,014,478	890,350
Prepaid pension cost		763,254	768,998
Right-of-use assets		522,936	549,668
Security deposits		83,204	83,343
Loans held for sale		103,592	228,995
Other	[1]	1,272,162	1,069,348
Total		8,280,151	9,700,960
Other liabilities:
Payables to brokers, dealers and customers for securities transactions		1,049,094	1,799,116
Other		639,106	527,493
Guaranteed trust principal	[2]	785,292	817,448
Lease liabilities		548,699	571,087
Collateral accepted for derivative transactions		1,382,985	1,008,083
Margins accepted for futures contracts		25,405	81,925
Unearned income		101,150	112,077
Other		1,737,267	1,399,466
Total		¥ 6,268,999	¥ 6,316,695
[1]The MHFG Group included premises and equipment classified as held for sale in Other.[2]Guaranteed trust principal, included in All other liabilities in the disclosure about consolidated VIEs in the accompanying balance sheets, is a liability of certain consolidated trust arrangements that meet the definition of a VIE for which the MHFG Group provides guarantees for the repayment of principal. See Note 23 “Variable interest entities and securitizations” for further discussion of the guaranteed principal money trusts.

Preferred Stock (Composition of

Preferred Stock (Composition of Preferred Stock) (Detail) - shares	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Class Fourteen Preferred Stock
Class of Stock [Line Items]
Number of shares Authorized	90,000,000	90,000,000	90,000,000
Number of shares Issued	0	0	0
Class Fifteen Preferred Stock
Class of Stock [Line Items]
Number of shares Authorized	90,000,000	90,000,000	90,000,000
Number of shares Issued	0	0	0
Class Sixteen Preferred Stock
Class of Stock [Line Items]
Number of shares Authorized	150,000,000	150,000,000	150,000,000
Number of shares Issued	0	0	0

Common Stock - Summary of Chang

Common Stock - Summary of Changes in Number of Issued Shares of Common Stock (Detail) - shares	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Class of Stock [Line Items]
Balance at beginning of fiscal year	2,539,249,894	2,539,249,894	2,539,249,894
Issuance of new shares of common stock due to exercise of stock acquisition rights	0	0	0
Balance at end of fiscal year	2,539,249,894	2,539,249,894	2,539,249,894

Dividends - Additional Informat

Dividends - Additional Information (Detail) ¥ in Millions	12 Months Ended
	Mar. 31, 2024 JPY (¥)
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Capital stock	¥ 2,256,768
Capital surplus	1,196,660
Retained earnings	¥ 2,532,933
Description of dividend payment restrictions	Pursuant to the Companies Act, in making a distribution of retained earnings, an entity must set aside in its legal reserve an amount equal to one-tenth of the amount of retained earnings so distributed, until its legal reserve reaches one-quarter of its capital stock.
Legal reserve	¥ 1,201,010
Maximum amount available for dividends under Company Law and the Banking Law	2,521,140
Japan Gaap Additional PaidIn Capital [Member]
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Legal reserve	1,196,660
Japan Gaap Retained Earnings [Member]
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Legal reserve	¥ 4,350

Accumulated other comprehensi_3

Accumulated other comprehensive income (loss), net of tax (Changes in Each Component of AOCI) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of fiscal year		¥ 9,725,134	¥ 9,442,231
Less: reclassification adjustments for losses (gains) included in net income		(27,115)
Change during year		336,163	209,687	¥ 126,593
Balance at end of fiscal year		10,431,187	9,725,134	9,442,231
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of fiscal year	[1]	649,395	440,112	318,114
Change during year	[1]	335,184	209,283	121,998
Balance at end of fiscal year	[1]	984,578	649,395	440,112
Net unrealized gains (losses) on available-for-sale securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of fiscal year		(31,084)	(25,046)	(8,173)
Unrealized gains (losses) during year		20,972	(7,472)	(35,922)
Less: reclassification adjustments for losses (gains) included in net income		12,173	1,434	19,049
Change during year		33,145	(6,038)	(16,873)
Balance at end of fiscal year		2,061	(31,084)	(25,046)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of fiscal year		227,660	94,104	(86,873)
Foreign currency translation adjustments during year		258,887	133,556	181,722
Less: reclassification adjustments for losses (gains) included in net income		(18,682)	0	(745)
Change during year		240,204	133,556	180,977
Balance at end of fiscal year		467,864	227,660	94,104
Defined benefit plan adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of fiscal year		423,677	355,355	397,153
Unrealized gains (losses) during year		97,847	86,326	(22,825)
Less: reclassification adjustments for losses (gains) included in net income		(21,861)	(18,004)	(18,973)
Change during year		75,986	68,322	(41,798)
Balance at end of fiscal year		499,663	423,677	355,355
Accumulated Own Credit Risk Adjustment Including Portion Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of fiscal year		29,142	15,699	16,007
Unrealized gains (losses) during year		(15,403)	12,688	(858)
Less: reclassification adjustments for losses (gains) included in net income		1,251	755	550
Change during year		(14,152)	13,443	(308)
Balance at end of fiscal year		¥ 14,990	¥ 29,142	¥ 15,699
[1]The amounts that have been reclassified out of Accumulated other comprehensive income (loss), net of tax into net income are presented in Note 16 “Accumulated other comprehensive income (loss), net of tax.”

Accumulated other comprehensi_4

Accumulated other comprehensive income (loss), net of tax (Amounts Reclassified Out of Accumulated Other Comprehensive Income into Net Income) (Detail) ¥ in Millions	12 Months Ended
	Mar. 31, 2024 JPY (¥)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Before tax	¥ 31,171	[1]
Tax effect	(4,056)	[2]
Net of tax before allocation to noncontrolling interests	27,115
Net of tax attributable to noncontrolling interests	3	[2]
Net of tax attributable to MHFG shareholders	27,118
Accumulated Net unrealized gains (losses) on available-for-sale securities | Investment gains (losses) net
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Before tax	(17,325)	[1]
Tax effect	5,151	[2]
Net of tax before allocation to noncontrolling interests	(12,173)
Net of tax attributable to noncontrolling interests	0	[2]
Net of tax attributable to MHFG shareholders	(12,173)
Accumulated Foreign currency translation adjustments | Foreign exchange gains (losses)—net Other noninterest income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Before tax	18,682	[1]
Tax effect	0	[2]
Net of tax before allocation to noncontrolling interests	18,682
Net of tax attributable to noncontrolling interests	0	[2]
Net of tax attributable to MHFG shareholders	18,682
Accumulated Defined Benefit Plans Adjustment | Salaries and employee benefits
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Before tax	31,617	[1]
Tax effect	(9,759)	[2]
Net of tax before allocation to noncontrolling interests	21,858
Net of tax attributable to noncontrolling interests	3	[2]
Net of tax attributable to MHFG shareholders	21,861
Accumulated Own Credit Risk Adjustment | Other Noninterest Income (Expenses)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Before tax	(1,804)	[1]
Tax effect	552	[2]
Net of tax before allocation to noncontrolling interests	(1,251)
Net of tax attributable to noncontrolling interests	0	[2]
Net of tax attributable to MHFG shareholders	¥ (1,251)
[1]The financial statement line item in which the amounts in the before tax column are reported in the consolidated statements of income is listed to the right of the table.[2]The financial statement line items in which the amounts in the tax effect and the net of tax attributable to noncontrolling interest columns are reported in the consolidated statements of income are Income tax expense (benefit) and Net income (loss), respectively.

Regulatory Matters (Capital Req

Regulatory Matters (Capital Requirements and Regulatory Adjustments Over Transitional Period) (Detail)		12 Months Ended
		Mar. 31, 2024		Mar. 31, 2023
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Capital conservation buffer		2.50%		2.50%
March 2023
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		8%
Capital conservation buffer		2.50%
Countercyclical capital buffer		0.06%	[1]	0.06%
Additional loss absorbency requirements for G-SIBs and D-SIBs		1%	[2]	1%
Minimum Leverage Ratio	[3]	3.50%
March 2023 | Common Equity Tier 1 Capital
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		4.50%
March 2023 | Tier I
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		6%
March 2024
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		8%
Capital conservation buffer		2.50%
Countercyclical capital buffer	[1]	0.09%
Additional loss absorbency requirements for G-SIBs and D-SIBs	[2]	1%
Minimum Leverage Ratio	[3]	3.50%
March 2024 | Common Equity Tier 1 Capital
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		4.50%
March 2024 | Tier I
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		6%
March 2025
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		8%
Capital conservation buffer		2.50%
Countercyclical capital buffer	[1]	0.09%
Additional loss absorbency requirements for G-SIBs and D-SIBs	[2]	1%
Minimum Leverage Ratio	[3]	3.70%
March 2025 | Common Equity Tier 1 Capital
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		4.50%
March 2025 | Tier I
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		6%
March 2026
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		8%
Capital conservation buffer		2.50%
Countercyclical capital buffer	[1]	0.09%
Additional loss absorbency requirements for G-SIBs and D-SIBs	[2]	1%
Minimum Leverage Ratio	[3]	3.70%
March 2026 | Common Equity Tier 1 Capital
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		4.50%
March 2026 | Tier I
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		6%
[1]Figures assume that the countercyclical capital buffer will continue to be 0.09% after March 2024.[2]Figures assume that the additional loss absorbency requirements applied to the Group as a G-SIB and D-SIB continue to be 1.0% on a fully effective basis in future years.[3]The ratios disclosed above include a leverage ratio buffer required to be met at 50% of the additional loss absorbency requirements applied to the Group as a G-SIB under the finalized Basel III reforms.

Regulatory Matters (Capital R_2

Regulatory Matters (Capital Requirements and Regulatory Adjustments Over Transitional Period) (Parenthetical) (Detail)	12 Months Ended
	Mar. 31, 2024
March 2023
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Countercyclical capital buffer	0.09%	[1]
Additional loss absorbency requirements for G-SIBs and D-SIBs	1%	[2]
March 2024
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Countercyclical capital buffer	0.09%	[1]
Additional loss absorbency requirements for G-SIBs and D-SIBs	1%	[2]
March 2024 | Basel III
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Leverage ratio buffer	50%
March 2026
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Additional loss absorbency requirements for G-SIBs and D-SIBs	1%
[1]Figures assume that the countercyclical capital buffer will continue to be 0.09% after March 2024.[2]Figures assume that the additional loss absorbency requirements applied to the Group as a G-SIB and D-SIB continue to be 1.0% on a fully effective basis in future years.

Regulatory Matters (Capital Ade

Regulatory Matters (Capital Adequacy Ratios of MHFG, MHBK, and MHTB Calculated in Accordance with Japanese GAAP and Guidelines Established by Financial Services Agency) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2024	Mar. 31, 2023
Common Equity Tier 1 capital:
Actual		¥ 2,256,768
Required, ratio		120%
Mizuho Financial Group, Inc. | Consolidated
Common Equity Tier 1 capital:
Required, amount	[1]	¥ 5,883,000	¥ 5,676,000
Actual		9,259,000	8,315,000
Required, amount	[1]	6,973,000	6,733,000
Actual		¥ 10,801,000	¥ 9,803,000
Required, ratio	[1]	9.59%	9.56%
Actual		14.85%	13.91%
Required, amount	[1]	¥ 8,428,000	¥ 8,142,000
Actual		¥ 12,314,000	¥ 11,306,000
Required, ratio	[1]	11.59%	11.56%
Actual		16.93%	16.05%
Required, amount	[2],[3]	¥ 8,028,000	¥ 7,680,000
Actual	[2]	¥ 10,801,000	¥ 9,803,000
Common Equity Tier 1 capital:
Required, ratio	[1]	8.09%	8.06%
Actual		12.73%	11.80%
Leverage Ratio:
Required, ratio	[2],[3]	3.50%	3.50%
Actual	[2]	4.70%	4.46%
Mizuho Bank Limited | Consolidated
Common Equity Tier 1 capital:
Required, amount		¥ 2,968,000	¥ 2,941,000
Actual		7,431,000	6,873,000
Required, amount		3,957,000	3,922,000
Actual		¥ 8,973,000	¥ 8,356,000
Required, ratio		6%	6%
Actual		13.60%	12.78%
Required, amount		¥ 5,276,000	¥ 5,229,000
Actual		¥ 10,400,000	¥ 9,769,000
Required, ratio		8%	8%
Actual		15.76%	14.94%
Required, amount	[2]	¥ 6,382,000	¥ 6,216,000
Actual	[2]	¥ 8,973,000	¥ 8,356,000
Common Equity Tier 1 capital:
Required, ratio		4.50%	4.50%
Actual		11.26%	10.51%
Leverage Ratio:
Required, ratio	[2]	3%	3%
Actual	[2]	4.21%	4.03%
Mizuho Bank Limited | Non-consolidated
Common Equity Tier 1 capital:
Required, amount		¥ 2,716,000	¥ 2,751,000
Actual		6,273,000	5,981,000
Required, amount		3,621,000	3,668,000
Actual		¥ 7,805,000	¥ 7,450,000
Required, ratio		6%	6%
Actual		12.93%	12.18%
Required, amount		¥ 4,828,000	¥ 4,891,000
Actual		¥ 9,185,000	¥ 8,853,000
Required, ratio		8%	8%
Actual		15.21%	14.48%
Required, amount	[2]	¥ 5,867,000	¥ 5,767,000
Actual	[2]	¥ 7,805,000	¥ 7,450,000
Common Equity Tier 1 capital:
Required, ratio		4.50%	4.50%
Actual		10.39%	9.78%
Leverage Ratio:
Required, ratio	[2]	3%	3%
Actual	[2]	3.99%	3.87%
Mizuho Trust & Banking Company Limited | Consolidated
Common Equity Tier 1 capital:
Required, amount		¥ 74,000	¥ 77,000
Actual		476,000	444,000
Required, amount		98,000	102,000
Actual		¥ 476,000	¥ 444,000
Required, ratio		6%	6%
Actual		28.98%	25.94%
Required, amount		¥ 131,000	¥ 137,000
Actual		¥ 476,000	¥ 444,000
Required, ratio		8%	8%
Actual		28.99%	25.95%
Required, amount	[2]	¥ 123,000	¥ 125,000
Actual	[2]	¥ 476,000	¥ 444,000
Common Equity Tier 1 capital:
Required, ratio		4.50%	4.50%
Actual		28.98%	25.94%
Leverage Ratio:
Required, ratio	[2]	3%	3%
Actual	[2]	11.62%	10.61%
Mizuho Trust & Banking Company Limited | Non-consolidated
Common Equity Tier 1 capital:
Required, amount		¥ 70,000	¥ 76,000
Actual		446,000	425,000
Required, amount		93,000	101,000
Actual		¥ 446,000	¥ 425,000
Required, ratio		6%	6%
Actual		28.60%	25.10%
Required, amount		¥ 124,000	¥ 135,000
Actual		¥ 446,000	¥ 425,000
Required, ratio		8%	8%
Actual		28.60%	25.11%
Required, amount	[2]	¥ 118,000	¥ 122,000
Actual	[2]	¥ 446,000	¥ 425,000
Common Equity Tier 1 capital:
Required, ratio		4.50%	4.50%
Actual		28.60%	25.10%
Leverage Ratio:
Required, ratio	[2]	3%	3%
Actual	[2]	11.31%	10.44%
[1]The required ratios disclosed above, at March 31, 2023 and 2024, include the capital conservation buffer of 2.5%, the countercyclical capital buffer of 0.06% and 0.09%, respectively, and the additional loss absorbency requirements for G-SIBs and D-SIBs of 1.0%, which are all in addition to the regulatory minima. The respective required amounts are determined by applying the ratios to the sum of the risk weighted assets and certain other risk amounts.[2]The required and actual amounts disclosed above at March 31, 2023 and 2024 exclude amounts of deposits to the Bank of Japan.[3]The required ratios disclosed above, at March 31, 2023 and 2024, include a leverage ratio buffer required to be met at 50% of the additional loss absorbency requirements applied to the Group as a G-SIB under the finalized Basel III reforms.

Regulatory Matters (Capital A_2

Regulatory Matters (Capital Adequacy Ratios of MHFG, MHBK, and MHTB Calculated in Accordance with Japanese GAAP and Guidelines Established by Financial Services Agency) (Parenthetical) (Detail)		12 Months Ended
		Mar. 31, 2024		Mar. 31, 2023
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Capital conservation buffer		2.50%		2.50%
March 2023
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Capital conservation buffer		2.50%
Additional loss absorbency requirements for G-SIBs and D-SIBs		1%	[1]	1%
Countercyclical capital buffer		0.06%	[2]	0.06%
Leverage ratio buffer				0.50
March 2024
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Capital conservation buffer		2.50%
Additional loss absorbency requirements for G-SIBs and D-SIBs	[1]	1%
Countercyclical capital buffer	[2]	0.09%
Leverage ratio buffer		0.50
[1]Figures assume that the additional loss absorbency requirements applied to the Group as a G-SIB and D-SIB continue to be 1.0% on a fully effective basis in future years.[2]Figures assume that the countercyclical capital buffer will continue to be 0.09% after March 2024.

Regulatory Matters - Additional

Regulatory Matters - Additional Information (Detail)	12 Months Ended
	Mar. 31, 2024
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements [Line Items]
Capital adequacy ratio	120%
Description of regulatory actions for not maintaining the minimum capital ratio concerning securities subsidiaries	A capital ratio of less than 140% will call for regulatory reporting and a capital ratio of less than 100% may lead to a temporary suspension of all or part of the business operations and further, to the cancellation of the license to act as a securities broker and dealer.
Minimum | Regulatory reporting
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements [Line Items]
Capital adequacy ratio	140%
Minimum | Temporary suspension
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements [Line Items]
Capital adequacy ratio	100%

Earnings Per Common Share (Comp

Earnings Per Common Share (Computation of Basic and Diluted Earnings Per Common Share) (Detail) - JPY (¥) ¥ / shares in Units, shares in Thousands, ¥ in Millions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Net income (loss):
Net income (loss) attributable to MHFG common shareholders		¥ 912,473	¥ (14,009)	¥ (104,722)
Effect of dilutive securities
Effect of dilutive securities		0	0	0
Net income (loss) attributable to common shareholders after assumed conversions		¥ 912,473	¥ (14,009)	¥ (104,722)
Shares:
Weighted average common shares outstanding		2,536,775	2,536,596	2,537,051
Effect of dilutive securities:
Stock options and the common shares of MHFG under the stock compensation programs	[1]	325	0	0
Weighted average common shares after assumed conversions		2,537,100	2,536,596	2,537,051
Earnings per common share:
Basic net income (loss) per common share		¥ 359.7	¥ (5.52)	¥ (41.28)
Diluted net income (loss) per common share	[1]	¥ 359.65	¥ (5.52)	¥ (41.28)
[1]For the fiscal years ended March 31, 2022 and 2023, the performance-based plan under the stock compensation programs could potentially dilute earnings per common share but were not included in the computation of diluted earnings per common share due to their antidilutive effects. In addition, for the fiscal years ended March 31, 2022 and 2023, the computation of diluted earnings per common share did not assume exercise of stock options, as the effect of such exercise would be antidilutive due to net loss.

Income Taxes (Components of Inc

Income Taxes (Components of Income Tax Expense (Benefit)) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Current:
Domestic	¥ 36,237	¥ 22,015	¥ 42,401
Foreign	223,529	156,969	71,947
Total current tax expense	259,765	178,984	114,348
Deferred:
Domestic	170,106	(146,721)	(256,093)
Foreign	(4,750)	2,879	728
Total deferred tax expense (benefit)	165,355	(143,842)	(255,365)
Total income tax expense (benefit)	¥ 425,120	¥ 35,142	¥ (141,017)

Income Taxes (Detailed Amounts

Income Taxes (Detailed Amounts of Tax Effects of Items Recorded Directly in Equity) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Net unrealized gains (losses) on available-for-sale securities:
Unrealized gains (losses)	¥ 8,273	¥ (4,276)	¥ (16,489)
Less: reclassification adjustments	5,151	305	8,504
Total	13,425	(3,971)	(7,985)
Defined benefit plan adjustments:
Unrealized gains (losses)	42,415	37,661	(9,020)
Less: reclassification adjustments	(9,759)	(7,848)	(7,748)
Total	32,655	29,813	(16,768)
Own credit risk adjustments:
Unrealized gains (losses)	(6,590)	5,630	1,745
Less: reclassification adjustments	552	334	271
Total	(6,038)	5,964	2,016
Total tax effect before allocation to noncontrolling interests	¥ 40,043	¥ 31,806	¥ (22,737)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Income Taxes [Line Items]
Net operating loss carryforwards	[1],[2]	¥ 423,000
Changes that directly affected Income tax expense		(38,055)	¥ (4,118)	¥ 16,196
Change in valuation allowance		73,246	39,754	17,818
Unrecognized tax benefits, that would affect effective tax rate		7,639	7,043	5,245
Unrecognized tax benefits, interest and penalties		3,014	¥ 2,286	¥ 1,812
Mizuho Financial Group, Inc.
Income Taxes [Line Items]
Undistributed earnings		433,000
Deferred tax liabilities		¥ 44,000
[1]Net operating loss carryforwards related to Japanese local taxes recorded at MHBK in the fiscal year ended March 31, 2024 in the amount of ¥456 billion (tax effected ¥16 billion) are not included in the table. The net operating loss carryforwards will mostly expire during the fiscal year ending March 31, 2034.[2]Net operating loss carryforwards related to Japanese local taxes recorded at MHFG in the fiscal year ended March 31, 2022 in the amount of ¥500 billion (tax effected ¥24 billion) are not included in the table. The net operating loss carryforwards are fully offset by valuation allowance and will mostly expire during the fiscal year ending March 31, 2032.

Income Taxes (Reconciliation of

Income Taxes (Reconciliation of Income Tax Expense at Effective Statutory Tax Rate to Actual Income Tax Expense) (Detail)	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Reconciliation Of Income Tax Expense Benefit And Statutory Federal Tax Rate [Line Items]
Effective statutory tax rate	30.62%	30.62%	30.62%
Income not subject to tax	(0.58%)	(14.23%)	4.21%
Expenses not deductible for tax purposes	0.08%	1.63%	(0.34%)
Tax rate differentials of subsidiaries	(0.92%)	(12.95%)	3.31%
Change in valuation allowance	(2.34%)	(5.95%)	(6.68%)	[1]
Change in undistributed earnings of subsidiaries	0.52%	8.32%	(2.22%)
Noncontrolling interest income (loss) of consolidated VIEs	(5.35%)	(15.48%)	(2.10%)
Effect of enacted change in tax rates	0%	(0.05%)	0.01%
Reversal of outside basis differences	0%	0%	50.59%	[1]
Foreign tax credit and payments	3.80%	55.14%	(16.59%)
Income excluded from taxable income of enterprise tax	(1.04%)	(14.96%)	2.86%
Controlled foreign company rules	0.06%	2.68%	(1.66%)
Other	1.34%	16.04%	(3.86%)
Effective income tax rate	26.19%	50.81%	58.15%
[1]These amounts for the fiscal year ended March 31, 2022 mainly represent the reversal of an outside basis difference related to the share buyback conducted by MHSC in response to improving the capital position and aligning to the MHFG Group’s capital policy and the related increase in the valuation allowance.

Income Taxes (Components of Net

Income Taxes (Components of Net Deferred Tax Assets) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2024		Mar. 31, 2023		Mar. 31, 2022	Mar. 31, 2021
Deferred tax assets:
Allowance for credit losses		¥ 265,855		¥ 270,423
Trading securities		208,711		173,793
Lease liabilities		168,848		176,304
Derivative financial instruments		148,716		161,141
Foreign tax credit and payments	[1]	124,695		54,416
Premises and equipment		46,967		53,531
Available-for-sale securities		0		13,020
Net operating loss carryforwards	[2],[3]	149,521		168,387
Other		290,733		201,141
Deferred Tax Assets, Gross, Total		1,404,047		1,272,156
Valuation allowance		(233,991)	[1],[2],[3]	(198,800)	[1],[2],[3]	¥ (163,164)	¥ (129,150)
Deferred tax assets, net of valuation allowance		1,170,057		1,073,356
Deferred tax liabilities:
Investments		502,589		264,147
Prepaid pension cost and accrued pension liabilities		222,408		224,173
Right-of-use assets		160,630		169,353
Available-for-sale securities		404		0
Other		120,104		54,515
Deferred tax liabilities		1,006,135		712,188
Net deferred tax assets		¥ 163,921		¥ 361,168
[1]The amount includes ¥37,517 million and ¥99,994 million related to MHBK’s foreign tax credit carryforwards as of March 31, 2023 and 2024, respectively. The amount is fully offset by valuation allowance, and if not utilized, the amount will expire during the fiscal years ending March 31, 2026 and 2027, respectively.[2]The amount includes ¥24,978 million and ¥25,128 million related to MHFG’s net operating loss carryforwards resulting mainly from intercompany capital transactions in relation to the share buyback conducted by MHSC as of March 31, 2023 and 2024, respectively. The tax effect of the net operating loss carryforwards is fully offset by ¥24,978 million and ¥25,128 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income.[3]The amount includes ¥49,393 million and ¥9,186 million related to MHSC’s net operating loss carryforwards resulting mainly from the organizational restructuring of certain foreign subsidiaries as of March 31, 2023 and 2024, respectively. The tax effect of the net operating loss carryforwards is substantially offset by ¥43,488 million and ¥4,205 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income.

Income Taxes (Components of N_2

Income Taxes (Components of Net Deferred Tax Assets) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2024		Mar. 31, 2023		Mar. 31, 2022	Mar. 31, 2021
Schedule Of Deferred Income Tax Assets And Liabilities [Line Items]
Deferred tax assets foreign tax credit forwards	[1]	¥ 124,695		¥ 54,416
Net operating loss carryforwards	[2],[3]	149,521		168,387
Valuation allowance		233,991	[1],[2],[3]	198,800	[1],[2],[3]	¥ 163,164	¥ 129,150
Mizuho Bank Limited
Schedule Of Deferred Income Tax Assets And Liabilities [Line Items]
Deferred tax assets foreign tax credit forwards		99,994		37,517
Mizuho Securities Company Limited
Schedule Of Deferred Income Tax Assets And Liabilities [Line Items]
Net operating loss carryforwards		9,186		49,393
Valuation allowance		4,205		43,488
Mizuho Financial Group, Inc.
Schedule Of Deferred Income Tax Assets And Liabilities [Line Items]
Net operating loss carryforwards		25,128		24,978
Valuation allowance		¥ 25,128		¥ 24,978
Earliest Tax Year [Member] | Mizuho Bank Limited
Schedule Of Deferred Income Tax Assets And Liabilities [Line Items]
Operating loss carryforwards, expiration date		Mar. 31, 2026		Mar. 31, 2026
Latest Tax Year [Member] | Mizuho Bank Limited
Schedule Of Deferred Income Tax Assets And Liabilities [Line Items]
Operating loss carryforwards, expiration date		Mar. 31, 2027		Mar. 31, 2027
[1]The amount includes ¥37,517 million and ¥99,994 million related to MHBK’s foreign tax credit carryforwards as of March 31, 2023 and 2024, respectively. The amount is fully offset by valuation allowance, and if not utilized, the amount will expire during the fiscal years ending March 31, 2026 and 2027, respectively.[2]The amount includes ¥24,978 million and ¥25,128 million related to MHFG’s net operating loss carryforwards resulting mainly from intercompany capital transactions in relation to the share buyback conducted by MHSC as of March 31, 2023 and 2024, respectively. The tax effect of the net operating loss carryforwards is fully offset by ¥24,978 million and ¥25,128 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income.[3]The amount includes ¥49,393 million and ¥9,186 million related to MHSC’s net operating loss carryforwards resulting mainly from the organizational restructuring of certain foreign subsidiaries as of March 31, 2023 and 2024, respectively. The tax effect of the net operating loss carryforwards is substantially offset by ¥43,488 million and ¥4,205 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income.

Income Taxes (Breakdown of Net

Income Taxes (Breakdown of Net Operating Loss Carryforwards by Tax Jurisdiction) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2024		Mar. 31, 2023
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards	[1],[2]	¥ 149,521		¥ 168,387
Operating loss, Valuation allowance		(123,000)		(152,000)
Deferred tax assets, net of valuation allowance		26,000		16,000
Japan
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards		56,000	[3]	89,000	[4]
Operating loss, Valuation allowance		(34,000)	[3]	(75,000)	[4]
Deferred tax assets, net of valuation allowance		22,000	[3]	14,000	[4]
United States of America
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards		4,000		1,000
Operating loss, Valuation allowance		0		0
Deferred tax assets, net of valuation allowance		4,000		1,000
United Kingdom
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards	[5]	88,000		77,000
Operating loss, Valuation allowance	[5]	(88,000)		(77,000)
Deferred tax assets, net of valuation allowance	[5]	0		0
Others
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards		1,000		1,000
Operating loss, Valuation allowance		0		0
Deferred tax assets, net of valuation allowance		¥ 1,000		¥ 1,000
[1]The amount includes ¥24,978 million and ¥25,128 million related to MHFG’s net operating loss carryforwards resulting mainly from intercompany capital transactions in relation to the share buyback conducted by MHSC as of March 31, 2023 and 2024, respectively. The tax effect of the net operating loss carryforwards is fully offset by ¥24,978 million and ¥25,128 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income.[2]The amount includes ¥49,393 million and ¥9,186 million related to MHSC’s net operating loss carryforwards resulting mainly from the organizational restructuring of certain foreign subsidiaries as of March 31, 2023 and 2024, respectively. The tax effect of the net operating loss carryforwards is substantially offset by ¥43,488 million and ¥4,205 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income.[3]¥25 billion of the Japan deferred tax assets of ¥56 billion is related to MHFG, which is fully offset by a valuation allowance, and will mostly expire during the fiscal year ending March 31, 2032. ¥16 billion of the Japan deferred tax assets of ¥56 billion is related to MHBK and will mostly expire during the fiscal year ending March 31, 2034.[4]¥49 billion of the Japan deferred tax assets of ¥89 billion is related to MHSC, which is substantially offset by a valuation allowance, and will expire during the fiscal year ending March 31, 2026. ¥25 billion of the Japan deferred tax assets of ¥89 billion is related to MHFG, which is fully offset by a valuation allowance, and will mostly expire during the fiscal year ending March 31, 2032.[5]The United Kingdom net operating loss carryforwards may be carried forward indefinitely for tax purposes.

Income Taxes (Breakdown of Ne_2

Income Taxes (Breakdown of Net Operating Loss Carryforwards by Tax Jurisdiction) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2024		Mar. 31, 2023
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards	[1],[2]	¥ 149,521		¥ 168,387
Japan
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards		56,000	[3]	89,000	[4]
Mizuho Securities Company Limited
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards		9,186		49,393
Mizuho Securities Company Limited | Japan
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards				¥ 49,000
Operating loss carryforwards, expiration date				Mar. 31, 2026
Mizuho Financial Group, Inc.
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards		25,128		¥ 24,978
Mizuho Financial Group, Inc. | Japan
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards		¥ 25,000		¥ 25,000
Operating loss carryforwards, expiration date		Mar. 31, 2032		Mar. 31, 2032
Mizuho Bank Limited | Japan
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards		¥ 16,000
Operating loss carryforwards, expiration date		Mar. 31, 2034
[1]The amount includes ¥24,978 million and ¥25,128 million related to MHFG’s net operating loss carryforwards resulting mainly from intercompany capital transactions in relation to the share buyback conducted by MHSC as of March 31, 2023 and 2024, respectively. The tax effect of the net operating loss carryforwards is fully offset by ¥24,978 million and ¥25,128 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income.[2]The amount includes ¥49,393 million and ¥9,186 million related to MHSC’s net operating loss carryforwards resulting mainly from the organizational restructuring of certain foreign subsidiaries as of March 31, 2023 and 2024, respectively. The tax effect of the net operating loss carryforwards is substantially offset by ¥43,488 million and ¥4,205 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income.[3]¥25 billion of the Japan deferred tax assets of ¥56 billion is related to MHFG, which is fully offset by a valuation allowance, and will mostly expire during the fiscal year ending March 31, 2032. ¥16 billion of the Japan deferred tax assets of ¥56 billion is related to MHBK and will mostly expire during the fiscal year ending March 31, 2034.[4]¥49 billion of the Japan deferred tax assets of ¥89 billion is related to MHSC, which is substantially offset by a valuation allowance, and will expire during the fiscal year ending March 31, 2026. ¥25 billion of the Japan deferred tax assets of ¥89 billion is related to MHFG, which is fully offset by a valuation allowance, and will mostly expire during the fiscal year ending March 31, 2032.

Income Taxes (Roll-forward of V

Income Taxes (Roll-forward of Valuation Allowance) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024		Mar. 31, 2023		Mar. 31, 2022
Valuation Allowance [Line Items]
Balance at beginning of fiscal year	¥ 198,800	[1],[2],[3]	¥ 163,164		¥ 129,150
Changes that directly affected Income tax expense	(38,055)		(4,118)		16,196
Expiration of net operating loss carryforwards	0		0		0
Others	73,246		39,754		17,818
Total	73,246		39,754		17,818
Balance at end of fiscal year	¥ 233,991	[1],[2],[3]	¥ 198,800	[1],[2],[3]	¥ 163,164
[1]The amount includes ¥24,978 million and ¥25,128 million related to MHFG’s net operating loss carryforwards resulting mainly from intercompany capital transactions in relation to the share buyback conducted by MHSC as of March 31, 2023 and 2024, respectively. The tax effect of the net operating loss carryforwards is fully offset by ¥24,978 million and ¥25,128 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income.[2]The amount includes ¥37,517 million and ¥99,994 million related to MHBK’s foreign tax credit carryforwards as of March 31, 2023 and 2024, respectively. The amount is fully offset by valuation allowance, and if not utilized, the amount will expire during the fiscal years ending March 31, 2026 and 2027, respectively.[3]The amount includes ¥49,393 million and ¥9,186 million related to MHSC’s net operating loss carryforwards resulting mainly from the organizational restructuring of certain foreign subsidiaries as of March 31, 2023 and 2024, respectively. The tax effect of the net operating loss carryforwards is substantially offset by ¥43,488 million and ¥4,205 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income.

Income Taxes (Net Operating Los

Income Taxes (Net Operating Losses Carryforwards by Expiration Date) (Detail) ¥ in Billions	Mar. 31, 2024 JPY (¥)	[1],[2]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	¥ 423
2025
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	0
2026
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	16
2027
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	3
2028
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	0
2029
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	5
2030 and thereafter
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	¥ 399	[3]
[1]Net operating loss carryforwards related to Japanese local taxes recorded at MHBK in the fiscal year ended March 31, 2024 in the amount of ¥456 billion (tax effected ¥16 billion) are not included in the table. The net operating loss carryforwards will mostly expire during the fiscal year ending March 31, 2034.[2]Net operating loss carryforwards related to Japanese local taxes recorded at MHFG in the fiscal year ended March 31, 2022 in the amount of ¥500 billion (tax effected ¥24 billion) are not included in the table. The net operating loss carryforwards are fully offset by valuation allowance and will mostly expire during the fiscal year ending March 31, 2032.[3]Including the net operating loss carryforwards which may be carried forward indefinitely in the United Kingdom.

Income Taxes (Net Operating L_2

Income Taxes (Net Operating Losses Carryforwards by Expiration Date) (Parenthetical) (Detail) - JPY (¥) ¥ in Billions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2022
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	[1],[2]	¥ 423
Mizuho Financial Group, Inc. | National Tax Agency, Japan [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards			¥ 500
Net operating loss carryforwards tax effected			¥ 24
Operating loss carryforwards, expiration date			Mar. 31, 2032
Mizuho Bank Limited | National Tax Agency, Japan [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards		456
Net operating loss carryforwards tax effected		¥ 16
Operating loss carryforwards, expiration date		Mar. 31, 2034
[1]Net operating loss carryforwards related to Japanese local taxes recorded at MHBK in the fiscal year ended March 31, 2024 in the amount of ¥456 billion (tax effected ¥16 billion) are not included in the table. The net operating loss carryforwards will mostly expire during the fiscal year ending March 31, 2034.[2]Net operating loss carryforwards related to Japanese local taxes recorded at MHFG in the fiscal year ended March 31, 2022 in the amount of ¥500 billion (tax effected ¥24 billion) are not included in the table. The net operating loss carryforwards are fully offset by valuation allowance and will mostly expire during the fiscal year ending March 31, 2032.

Income Taxes (Roll-forward of U

Income Taxes (Roll-forward of Unrecognized Tax Benefits) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Operating Loss Carryforwards [Line Items]
Total unrecognized tax benefits at beginning of fiscal year	¥ 7,043	¥ 5,245	¥ 4,401
Gross amount of increases (decreases) related to positions taken during prior years	205	(438)	(576)
Gross amount of increases related to positions taken during the current year	1,080	1,748	954
Amount of decreases related to settlements	(1,633)	0	0
Foreign exchange translation	944	488	466
Total unrecognized tax benefits at end of fiscal year	¥ 7,639	¥ 7,043	¥ 5,245

Pension and Other Employee Be_3

Pension and Other Employee Benefit Plans (Components of Net Periodic Costs of Severance Indemnities and Pension Plans) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Service cost-benefits earned during the fiscal year	¥ 28,936	¥ 30,460	¥ 33,190
Interest costs on projected benefit obligations	9,982	6,917	5,636
Expected return on plan assets	(34,565)	(36,322)	(37,051)
Amortization of prior service cost (benefits)	(4,890)	(4,854)	(4,820)
Amortization of net actuarial loss (gain)	(29,045)	(19,453)	(20,485)
Special termination benefits	1,244	7,269	10,791
Loss (gain) on settlement	2,210	0	0
Other	3,179	0	0
Net periodic benefit cost	¥ (22,948)	¥ (15,983)	¥ (12,739)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Interest Expense, Deposits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Investment Income, Interest

Pension and Other Employee Be_4

Pension and Other Employee Benefit Plans - Additional Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plans, costs recognized in respect of contributions to the plans	¥ 9,004	¥ 7,395	¥ 3,981
Aggregated accumulated benefit obligations	¥ 1,216,964	¥ 1,287,692
Description of requirements for lump-sum severance indemnities	Employees with service in excess of one year are qualified to receive lump-sum severance indemnities.
Pension plan, contribution expected to be paid during the next fiscal year	¥ 23,000

Pension and Other Employee Be_5

Pension and Other Employee Benefit Plans (Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss) Before-Tax) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Net actuarial gain (loss)	¥ 138,987	¥ 122,331
Amortization of net actuarial loss (gain)	(29,045)	(19,453)
Settlement loss (gain) of net actuarial loss (gain)	2,210	0
Amortization of prior service cost (benefits)	(4,890)	(4,854)
Total recognized in other comprehensive income (loss) before-tax	¥ 107,262	¥ 98,024

Pension and Other Employee Be_6

Pension and Other Employee Benefit Plans (Weighted-Average Assumptions Used to Determine Benefit Obligations and Net Periodic Benefit Cost) (Detail)	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Weighted-average assumptions used to determine benefit obligations at fiscal year end:
Discount rates	1%	0.82%	0.52%
Rates of increase in future compensation levels	2%	2%	2%
Interest credit rates	4.52%	4.45%	4.39%
Weighted-average assumptions used to determine net periodic benefit cost during the year:
Discount rates	0.82%	0.52%	0.38%
Rates of increase in future compensation levels	2%	2%	1.80%
Expected rates of return on plan assets	1.66%	1.72%	1.54%
Interest credit rates	4.45%	4.39%	4.38%

Pension and Other Employee Be_7

Pension and Other Employee Benefit Plans (Combined Funded Status and Amounts Recognized in Accompanying Consolidated Balance Sheets) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Change in benefit obligations:
Benefit obligations at beginning of fiscal year	¥ 1,287,692	¥ 1,377,739
Service cost	28,936	30,460	¥ 33,190
Interest cost	9,982	6,917	5,636
Plan participants' contributions	1,026	1,053
Actuarial loss (gain)	(23,767)	(48,856)
Foreign exchange translation	6,408	3,250
Benefits paid	(54,458)	(55,332)
Lump-sum payments	(17,838)	(27,539)
Settlement	(19,974)	0
Other	(1,045)	0
Benefit obligations at end of fiscal year	1,216,964	1,287,692	1,377,739
Change in plan assets:
Fair value of plan assets at beginning of fiscal year	2,032,215	2,114,011
Actual return (negative return) on plan assets	140,967	92,893
Foreign exchange translation	7,204	3,158
Partial withdrawal of assets from employee retirement benefits trusts (Note)	(179,437)	(147,181)
Employer contributions	31,327	23,613
Plan participants' contributions	1,026	1,053
Benefits paid	(54,458)	(55,332)
Settlement	(20,549)	0
Other	(1,677)	0
Fair value of plan assets at end of fiscal year	1,956,619	2,032,215	¥ 2,114,011
Funded status	739,655	744,523
Amounts recognized in the consolidated balance sheets consist of:
Prepaid pension cost	763,254	768,998
Accrued pension liability	(23,600)	(24,475)
Net amount recognized	739,655	744,523
Amounts recognized in Accumulated other comprehensive income (loss) before-tax consist of:
Prior service benefits (cost)	53,216	58,173
Net actuarial gain (loss)	636,790	524,571
Net amount recognized	¥ 690,007	¥ 582,744

Pension and Other Employee Be_8

Pension and Other Employee Benefit Plans (Combined Funded Status and Amounts Recognized in Accompanying Consolidated Balance Sheets) (Parenthetical) (Detail) ¥ in Billions	12 Months Ended
	Mar. 31, 2024 JPY (¥)
Defined Benefit Plan Disclosure [Line Items]
Gain (loss) recognized	¥ 0

Pension and Other Employee Be_9

Pension and Other Employee Benefit Plans (Plans with Projected Benefit Obligations in Excess of Plan Assets and Plans with Accumulated Benefit Obligations in Excess of Plan Assets) (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	¥ 27,787	¥ 29,389
Fair value of plan assets	4,187	4,914
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	27,787	29,389
Fair value of plan assets	¥ 4,187	¥ 4,914

Pension and Other Employee B_10

Pension and Other Employee Benefit Plans (Target Allocation for Plan Assets Excluding those of Employee Retirement Benefit Trusts) (Detail)	Mar. 31, 2024
Asset category
Plan assets	100%
General Account Assets
Asset category
Plan assets	10%
Other assets
Asset category
Plan assets	5%
Foreign | Equity securities
Asset category
Plan assets	26%
Foreign | Debt securities
Asset category
Plan assets	24%
Japan | Equity securities
Asset category
Plan assets	3%
Japan | Debt securities
Asset category
Plan assets	32%

Pension and Other Employee B_11

Pension and Other Employee Benefit Plans (Fair Value of Plan Assets by Asset Category) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		¥ 1,956,619	¥ 2,032,215	¥ 2,114,011
Foreign | Common stocks | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		152,000	94,000
Foreign | Pooled funds | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[1]	11,000	8,000
Foreign | Pooled funds | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[1]	3,000	3,000
Foreign | Government bonds | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		168,000	187,000
Foreign | Other | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		31,000	15,000
All Other | General account of life insurance companies
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[2]	117,000	113,000
All Other | Other Invested Assets
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		32,000	106,000
All Other | Net Asset Value
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[3]	410,000	325,000
Japan | Common stocks | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[4]	907,000	1,018,000
Japan | Pooled funds | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[1]	13,000	11,000
Japan | Pooled funds | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[1]	9,000	8,000
Japan | Government bonds | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		85,000	123,000
Japan | Other | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		18,000	21,000
Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		1,336,000	1,514,000
Level 1 | Foreign | Common stocks | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		152,000	94,000
Level 1 | Foreign | Government bonds | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		148,000	173,000
Level 1 | All Other | Other Invested Assets
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[5]	38,000	101,000
Level 1 | Japan | Common stocks | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[4]	907,000	1,018,000
Level 1 | Japan | Pooled funds | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[1]	5,000	5,000
Level 1 | Japan | Government bonds | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		85,000	123,000
Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		210,000	193,000
Level 2 | Foreign | Pooled funds | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[1]	10,000	8,000
Level 2 | Foreign | Pooled funds | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[1]	3,000	3,000
Level 2 | Foreign | Government bonds | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		20,000	14,000
Level 2 | Foreign | Other | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		31,000	15,000
Level 2 | All Other | General account of life insurance companies
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[2]	117,000	113,000
Level 2 | All Other | Other Invested Assets
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		(6,000)	5,000
Level 2 | Japan | Pooled funds | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[1]	8,000	6,000
Level 2 | Japan | Pooled funds | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[1]	9,000	8,000
Level 2 | Japan | Other | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		¥ 18,000	¥ 21,000
[1]These classes primarily include pension investment fund trusts. Investments in these classes are generally measured at fair value and can be redeemed within a short-term period upon request.[2]Investments in this class are measured at conversion value, which is equivalent to fair value.[3]In accordance with ASC 820, certain plan assets that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy.[4]This class represents equity securities held in the employee retirement benefit trusts of ¥1,018 billion and ¥907 billion carried at fair value at March 31, 2023 and 2024, respectively, which are well-diversified across industries.[5]Amounts primarily include cash and short-term assets carried at fair value.

Pension and Other Employee B_12

Pension and Other Employee Benefit Plans (Fair Value of Plan Assets by Asset Category) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Equity securities held in the employee retirement benefit trusts	¥ 1,956,619	¥ 2,032,215	¥ 2,114,011
Equity securities | Common stocks
Defined Benefit Plan Disclosure [Line Items]
Equity securities held in the employee retirement benefit trusts	907,000	1,018,000
Equity securities | Common stocks | Japan
Defined Benefit Plan Disclosure [Line Items]
Equity securities held in the employee retirement benefit trusts	¥ 907,000	¥ 1,018,000

Pension and Other Employee B_13

Pension and Other Employee Benefit Plans (Forecasted Benefit Payments Including Effect of Expected Future Service) (Detail) ¥ in Millions	Mar. 31, 2024 JPY (¥)
Defined Benefit Plan Disclosure [Line Items]
2025	¥ 75,229
2026	75,337
2027	74,087
2028	76,580
2029	75,596
2030-2034	¥ 324,753

Derivative Financial Instrume_3

Derivative Financial Instruments (Summary of Notional and Fair Value Amounts of Derivative Instruments Outstanding) (Detail) - JPY (¥) ¥ in Billions		Mar. 31, 2024	Mar. 31, 2023
Derivatives, Fair Value [Line Items]
Notional amount	[1]	¥ 2,637,757	¥ 2,279,203
Interest rate contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	2,297,499	1,991,016
Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	300,337	257,392
Equity-related contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	15,914	7,149
Credit-related contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	22,969	22,748
Other contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	1,039	898
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	0
Fair value of derivative payables	[2]	0
Designated as Hedging Instrument | Interest rate contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	0
Fair value of derivative payables	[2]	0
Designated as Hedging Instrument | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	0
Fair value of derivative payables	[2]	0
Designated as Hedging Instrument | Equity-related contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	0
Fair value of derivative payables	[2]	0
Designated as Hedging Instrument | Credit-related contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	0
Fair value of derivative payables	[2]	0
Designated as Hedging Instrument | Other contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	0
Fair value of derivative payables	[2]	0
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	14,874	12,932
Fair value of derivative payables	[2]	14,918	12,896
Not Designated as Hedging Instrument | Interest rate contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	8,668	8,374
Fair value of derivative payables	[2]	8,712	8,517
Not Designated as Hedging Instrument | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	5,612	4,222
Fair value of derivative payables	[2]	5,582	4,013
Not Designated as Hedging Instrument | Equity-related contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	340	145
Fair value of derivative payables	[2]	394	197
Not Designated as Hedging Instrument | Credit-related contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	214	144
Fair value of derivative payables	[2]	180	126
Not Designated as Hedging Instrument | Other contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	40	47
Fair value of derivative payables	[2]	¥ 50	¥ 43
[1]Notional amount includes the sum of gross long and gross short third-party contracts.[2]Derivative receivables and payables are recorded in Trading account assets and Trading account liabilities, respectively.

Derivative Financial Instrume_4

Derivative Financial Instruments - Additional Information (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023
Derivative [Line Items]
Cash collateral provided and not offset against derivative positions and included in Other assets	¥ 1,406,369	¥ 988,881
Cash collateral accepted and not offset against derivative positions and included in Other liabilities	1,382,985	1,008,083
Mizuho Financial Group, Inc.
Derivative [Line Items]
Cash collateral provided and not offset against derivative positions and included in Other assets	¥ 1,406,000	¥ 989,000

Derivative Financial Instrume_5

Derivative Financial Instruments (Summary of Gains and Losses on Derivatives not Designated or Qualifying as Hedges) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income	¥ 560,806	¥ 399,073	¥ 737,778
Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income	(22,003)	(508,743)	(130,312)
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income	387,591	317,459	145,979
Equity-related contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income	240,277	534,615	728,226
Credit-related contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income	(3,053)	(3,857)	(13,877)
Other contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income	¥ (42,005)	¥ 59,599	¥ 7,762

Derivative Financial Instrume_6

Derivative Financial Instruments (Summary of Gains and Losses on Derivatives not Designated or Qualifying as Hedges) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income	¥ 560,806	¥ 399,073	¥ 737,778
Credit-related contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income	(3,053)	(3,857)	(13,877)
Credit-related contracts | Loans related to credit derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income	¥ (952)	¥ (653)	¥ (605)

Derivative Financial Instrume_7

Derivative Financial Instruments (Summary of Notional and Fair Value Amounts of Credit Derivatives) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2024	Mar. 31, 2023
Credit protection written
Credit Derivatives [Line Items]
Notional amount	¥ 10,145	¥ 10,271
Fair value	147	93
Credit protection written | Investment grade
Credit Derivatives [Line Items]
Notional amount	6,183	4,497
Fair value	110	31
Credit protection written | Non-investment grade
Credit Derivatives [Line Items]
Notional amount	3,962	5,774
Fair value	37	62
Credit protection purchased
Credit Derivatives [Line Items]
Notional amount	12,824	12,477
Fair value	¥ (114)	¥ (75)

Derivative Financial Instrume_8

Derivative Financial Instruments (Maximum Potential Amount of Future Payments for Credit Protection Written by Expiration Period) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2024	Mar. 31, 2023
Credit Derivatives [Line Items]
Maximum payout/Notional amount	¥ 10,145	¥ 10,271
One year or less
Credit Derivatives [Line Items]
Maximum payout/Notional amount	1,254	331
After one year through five years
Credit Derivatives [Line Items]
Maximum payout/Notional amount	8,610	9,585
After five years
Credit Derivatives [Line Items]
Maximum payout/Notional amount	¥ 281	¥ 355

Derivative Financial Instrume_9

Derivative Financial Instruments (Quantitative Information about Derivative Instruments with Credit-risk-related Contingent Features) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2024	Mar. 31, 2023
Credit Derivatives [Line Items]
Aggregate fair value of derivative instruments with credit-risk-related contingent features in net liability positions	¥ 1,304	¥ 814
Collateral provided to counterparties in the normal course of business	1,025	663
Amount required to be posted as collateral or settled immediately if credit-risk-related contingent features were triggered	¥ 279	¥ 151

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Commitments And Contingencies Disclosure [Line Items]
Carrying amount of guarantees and similar obligations	¥ 801,000	¥ 315,000
Carrying amounts of derivatives that are deemed to guarantees	765,000	285,000
Allowance for credit losses on off-balance-sheet instruments	9,585	6,581	¥ (14,819)
Other Liabilities
Commitments And Contingencies Disclosure [Line Items]
Allowance for credit losses on off-balance-sheet instruments	¥ 88,000	¥ 78,000

Commitments and Contingencies_2

Commitments and Contingencies (Summary of Maximum Potential Amount of Future Payments under Guarantees) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2024	Mar. 31, 2023
Performance guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	¥ 3,896	¥ 3,548
Guarantees on loans
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	348	228
Guarantees on securities
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	93	82
Other guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	3,543	3,306
Guarantees for repayment of trust principal
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	16	18
Liabilities of trust accounts
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	599	554
Derivative financial instruments
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	113,108	83,420
One year or less | Performance guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	2,390	1,954
One year or less | Guarantees on loans
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	258	149
One year or less | Guarantees on securities
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	42	14
One year or less | Other guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	2,809	2,339
One year or less | Guarantees for repayment of trust principal
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	0	0
One year or less | Liabilities of trust accounts
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	165	97
One year or less | Derivative financial instruments
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	78,356	53,774
After one year through five years | Performance guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	1,305	1,413
After one year through five years | Guarantees on loans
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	54	26
After one year through five years | Guarantees on securities
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	51	68
After one year through five years | Other guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	614	869
After one year through five years | Guarantees for repayment of trust principal
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	7	8
After one year through five years | Liabilities of trust accounts
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	225	282
After one year through five years | Derivative financial instruments
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	29,674	24,954
After five years | Performance guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	201	181
After five years | Guarantees on loans
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	36	53
After five years | Guarantees on securities
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	0	0
After five years | Other guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	120	98
After five years | Guarantees for repayment of trust principal
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	10	10
After five years | Liabilities of trust accounts
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	209	175
After five years | Derivative financial instruments
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	¥ 5,077	¥ 4,692

Commitments and Contingencies_3

Commitments and Contingencies (Summary of Maximum Potential Amount of Future Payments of Certain Guarantees Classified Based on Internal Ratings) (Detail) - Performance guarantees, Guarantees on loans, Guarantees on securities and Other guarantees - JPY (¥) ¥ in Billions	Mar. 31, 2024	Mar. 31, 2023
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	¥ 7,879	¥ 7,164
Investment grade
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	6,095	5,587
Non-investment grade
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	¥ 1,784	¥ 1,577

Commitments and Contingencies_4

Commitments and Contingencies (Summary of Contractual Amounts with Regard to Undrawn Commitments) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2024	Mar. 31, 2023
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance-sheet instruments, contractual amounts of the undrawn commitments	¥ 117,355	¥ 102,309
Commitments to Extend Credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance-sheet instruments, contractual amounts of the undrawn commitments	115,577	100,973
Commercial letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance-sheet instruments, contractual amounts of the undrawn commitments	¥ 1,778	¥ 1,336

Commitments and contingencies_5

Commitments and contingencies - Schedule Of Balance Sheet Information Related to Operating Lease (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Right-of-use assets	¥ 522,936	¥ 549,668
Lease liabilities	¥ 548,699	¥ 571,087
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Other liabilities (Note 12)	Other liabilities (Note 12)
Weighted average:
Remaining lease term	14 years	14 years 8 months 12 days
Discount rate	0.97%	0.66%

Commitments and contingencies_6

Commitments and contingencies - Schedule Of Operating Lease Cost And Supplemental Cash Flow Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Lease cost	¥ 104,314	¥ 101,808	¥ 111,907
Right-of-use assets obtained in exchange for new lease liabilities	52,831	65,417	51,901
Operating cash flows	¥ 83,100	¥ 86,329	¥ 101,223

Commitments and contingencies_7

Commitments and contingencies - Schedule Of Future Lease Payments Under Operating Leases (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
2025	¥ 80,982
2026	61,337
2027	49,138
2028	38,925
2029	33,301
2030 and thereafter	314,213
Total lease payments	577,895
Amount representing interest	29,196
Total lease liabilities for operating leases	¥ 548,699	¥ 571,087

Variable Interest Entities an_3

Variable Interest Entities and Securitizations (Consolidated Assets of Consolidated VIEs as well as Total Assets and Maximum Exposure to Loss for Significant Unconsolidated VIEs) (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Variable Interest Entity [Line Items]
Total assets of MHFG	¥ 272,173,152	¥ 248,780,722	¥ 231,550,700
Significant unconsolidated VIEs- Maximum exposure to loss	1,209,000	979,000
Consolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	12,631,365	12,153,544
Unconsolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	6,497,000	3,621,000
Asset-backed commercial paper/loan programs
Variable Interest Entity [Line Items]
Significant unconsolidated VIEs- Maximum exposure to loss	0	0
Asset-backed commercial paper/loan programs | Consolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	3,370,000	3,082,000
Asset-backed commercial paper/loan programs | Unconsolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	0	0
Asset-backed securitizations
Variable Interest Entity [Line Items]
Significant unconsolidated VIEs- Maximum exposure to loss	96,000	134,000
Asset-backed securitizations | Consolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	1,668,000	1,514,000
Asset-backed securitizations | Unconsolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	175,000	224,000
Investments in securitization products
Variable Interest Entity [Line Items]
Significant unconsolidated VIEs- Maximum exposure to loss	0	0
Investments in securitization products | Consolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	385,000	387,000
Investments in securitization products | Unconsolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	0	0
Investment funds
Variable Interest Entity [Line Items]
Significant unconsolidated VIEs- Maximum exposure to loss	1,113,000	845,000
Investment funds | Consolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	1,908,000	2,294,000
Investment funds | Unconsolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	6,322,000	3,397,000
Trust arrangements and other
Variable Interest Entity [Line Items]
Significant unconsolidated VIEs- Maximum exposure to loss	0	0
Trust arrangements and other | Consolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	5,300,000	4,877,000
Trust arrangements and other | Unconsolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	¥ 0	¥ 0

Variable Interest Entities an_4

Variable Interest Entities and Securitizations (Carrying Amounts and Classification of Assets and Liabilities on Consolidated Balance Sheets that Relate to Variable Interests in Significant Unconsolidated VIEs) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Assets on consolidated balance sheets
Trading account assets		¥ 36,759,812	¥ 29,641,038
Loans		97,694,674	93,474,798
Total assets		272,173,152	248,780,722	¥ 231,550,700
Liabilities on the MHFG Group's balance sheets and maximum exposure to loss related to unconsolidated VIEs:
Trading account liabilities		20,621,160	19,362,943
Total liabilities		261,741,965	239,055,588
Maximum exposure to loss		1,209,000	979,000
Unconsolidated VIEs
Assets on consolidated balance sheets
Total assets		6,497,000	3,621,000
Mizuho Financial Group, Inc. | Unconsolidated VIEs
Assets on consolidated balance sheets
Trading account assets		97,000	83,000
Investments		726,000	482,000
Loans		137,000	154,000
Total assets		960,000	719,000
Liabilities on the MHFG Group's balance sheets and maximum exposure to loss related to unconsolidated VIEs:
Trading account liabilities		3,000	1,000
Total liabilities		3,000	1,000
Maximum exposure to loss	[1]	¥ 1,209,000	¥ 979,000
[1]Amounts include gains and losses on currency swaps.

Variable Interest Entities an_5

Variable Interest Entities and Securitizations - Additional Information (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023
Consolidated MHFG's balance sheets
Long-term debt	¥ 16,277,331	¥ 14,893,023
Noncontrolling interests	502,116	809,643
Unconsolidated VIEs
Consolidated MHFG's balance sheets
Noncontrolling interests	¥ 408,000	719,000
Debt Instrument [Member]
Consolidated MHFG's balance sheets
Long-term debt		¥ 200,000

Summary of Noninterest Income (

Summary of Noninterest Income (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Disaggregation of Revenue [Line Items]
Fee and commission income		¥ 1,117,826	¥ 984,345	¥ 980,000
Foreign exchange gains (losses)—net	[1]	(19,390)	189,526	91,611
Trading account gains (losses)—net		390,260	(603,910)	(491,947)
Investment gains (losses)—net:
Debt securities		(6,446)	5,167	(14,777)
Equity securities		1,010,288	135,601	(60,563)
Equity in earnings (losses) of equity method investees—net	[2]	19,791	(26,999)	34,587
Gains on disposal of premises and equipment		10,128	4,920	9,943
Other noninterest income	[3],[4]	221,273	199,453	120,936
Total noninterest income		2,743,729	888,103	669,790
Premises and Equipment
Investment gains (losses)—net:
Gains on disposal of premises and equipment	[2]	10,128	4,920	9,943
Foreign Exchange
Disaggregation of Revenue [Line Items]
Foreign exchange gains (losses)—net	[2]	(19,390)	189,526	91,611
Trading Account Gains
Disaggregation of Revenue [Line Items]
Trading account gains (losses)—net	[3]	390,260	(603,910)	(491,947)
Debt securities
Investment gains (losses)—net:
Debt securities	[2]	(6,446)	5,167	(14,777)
Equity securities
Investment gains (losses)—net:
Equity securities	[2]	1,010,288	135,601	(60,563)
Securities related business
Disaggregation of Revenue [Line Items]
Fee and commission income	[5]	246,865	190,026	184,014
Deposits related business
Disaggregation of Revenue [Line Items]
Fee and commission income	[5]	15,591	15,540	15,358
Lending related business
Disaggregation of Revenue [Line Items]
Fee and commission income	[3],[6]	232,626	193,838	162,953
Remittance business
Disaggregation of Revenue [Line Items]
Fee and commission income	[5]	106,762	104,201	103,979
Investment advisory, management and administrative service
Disaggregation of Revenue [Line Items]
Fee and commission income	[5]	115,504	109,358	122,014
Fiduciary and trust
Disaggregation of Revenue [Line Items]
Fee and commission income	[5]	136,800	130,576	141,365
Agency business
Disaggregation of Revenue [Line Items]
Fee and commission income	[5]	38,329	36,529	36,899
Guarantee-related business
Disaggregation of Revenue [Line Items]
Fee and commission income	[2]	43,791	41,150	35,296
Financial service, other
Disaggregation of Revenue [Line Items]
Fee and commission income	[5]	181,558	163,127	178,122
Financial service
Disaggregation of Revenue [Line Items]
Fee and commission income		¥ 1,117,826	¥ 984,345	¥ 980,000
[1]Amounts include realized and unrealized gains and losses on both derivative instruments and nonderivative instruments. Amounts on derivative instruments include gains and losses on forward foreign exchange contracts and currency options. Amounts on nonderivative instruments include translation gains and losses related to foreign currency-denominated debt securities reported as Trading securities.[2]These amounts are revenues from contracts that do not meet the scope of ASC 606.[3]Part of these amounts are considered to be revenues from contracts that are within the scope of ASC 606.[4]These amounts include the net unrealized gains resulting from changes in fair values of structured notes that contain embedded derivatives. See Note 26 “Fair value” for further details.[5]These amounts are revenues from contracts within the scope of ASC 606, “Revenue from contracts with customers” (“ASC 606”).[6]Most of the lending-related fees such as commitment fees and arrangement fees are not within the scope of ASC 606.

Noninterest Income - Additional

Noninterest Income - Additional Information (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Other Revenues [Line Items]
Trust fees		¥ 58,000	¥ 55,000	¥ 56,000
Fees related to trust business		79,000	76,000	85,000
Trading account gains (losses)—net		390,260	(603,910)	(491,947)
Other noninterest income	[1],[2]	221,273	199,453	120,936
Revenue from contracts with customers ("ASC 606")
Other Revenues [Line Items]
Trading account gains (losses)—net		93,000	59,000	83,000
Other noninterest income		¥ 25,000	¥ 21,000	¥ 15,000
[1]Part of these amounts are considered to be revenues from contracts that are within the scope of ASC 606.[2]These amounts include the net unrealized gains resulting from changes in fair values of structured notes that contain embedded derivatives. See Note 26 “Fair value” for further details.

Trading Account Gains and Los_3

Trading Account Gains and Losses (Net Trading Gains and Losses) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading account gains (losses)—net		¥ 390,260	¥ (603,910)	¥ (491,947)
Foreign exchange gains (losses)—net	[1]	(19,390)	189,526	91,611
Net trading gains (losses)		370,870	(414,384)	(400,336)
Interest rate contracts
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading account gains (losses)—net		(22,003)	(508,743)	(130,312)
Foreign exchange contracts
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading account gains (losses)—net	[2]	387,591	317,459	145,979
Equity-related contracts
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading account gains (losses)—net		240,277	534,615	728,226
Credit-related contracts
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading account gains (losses)—net	[3]	(2,101)	(3,204)	(13,272)
Other contracts
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading account gains (losses)—net		(42,005)	59,599	7,762
Trading securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading account gains (losses)—net		¥ (171,498)	¥ (1,003,636)	¥ (1,230,330)
[1]Amounts include realized and unrealized gains and losses on both derivative instruments and nonderivative instruments. Amounts on derivative instruments include gains and losses on forward foreign exchange contracts and currency options. Amounts on nonderivative instruments include translation gains and losses related to foreign currency-denominated debt securities reported as Trading securities.[2]Amounts include gains and losses on currency swaps.[3]Amounts do not include the net gains (losses) of ¥(605) million, ¥(653) million and ¥(952) million on the credit derivatives economically managing the credit risk of loans during the fiscal years ended March 31, 2022, 2023 and 2024, respectively. The net gains (losses) is recorded in Other noninterest income (expenses).

Trading Account Gains and Los_4

Trading Account Gains and Losses (Net Trading Gains and Losses) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Schedule of Trading Securities and Other Trading Assets [Line Items]
Gains (losses) recorded in income	¥ 560,806	¥ 399,073	¥ 737,778
Credit-related contracts
Schedule of Trading Securities and Other Trading Assets [Line Items]
Gains (losses) recorded in income	(3,053)	(3,857)	(13,877)
Credit-related contracts | Loans related to credit derivatives
Schedule of Trading Securities and Other Trading Assets [Line Items]
Gains (losses) recorded in income	¥ (952)	¥ (653)	¥ (605)

Fair Value - Additional Informa

Fair Value - Additional Information (Detail) - JPY (¥)	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Carrying amounts of other equity interests of which fair value is not readily determinable	¥ 358,000,000,000	¥ 208,000,000,000
Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held-for-sale	49	0
Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held-for-sale	81.8	99.6
Weighted Average [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held-for-sale	63.1	77.6
Senior borrowings and bonds
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
The differences between the aggregate fair value and aggregate unpaid principal balance of the notes for which the fair value option has been elected	62,000,000,000	161,000,000,000
Net unrealized gains (losses) resulting from changes in fair values of the notes	¥ (48,000,000,000)	54,000,000,000	¥ 38,000,000,000
Investment funds
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Underlying assets, estimated remaining liquidation period	10 years
Long-term debt
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of liabilities transferred into Level 3	¥ 1,000,000,000	1,000,000,000
Fair value of liabilities transferred out of Level 3	285,000,000,000	2,000,000,000
Trading securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of assets transferred into Level 3	15,000,000,000	13,000,000,000
Fair value of assets transferred out of Level 3	7,000,000,000	15,000,000,000
Available-for-sale securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of assets transferred out of Level 3	2,000,000,000	54,000,000,000
Derivative Financial Instruments, Assets [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of assets transferred out of Level 3	¥ 33,000,000,000
Other Investments [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of assets transferred out of Level 3		¥ 1,000,000,000

Fair Value (Summary of Assets a

Fair Value (Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis, Including Fair Value Option Elected) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2024	Mar. 31, 2023
Assets:
Available-for-sale securities		¥ 17,713,335	¥ 23,233,769
Liabilities:
Long-term debt		2,876,287	2,680,164
Other short-term borrowings		153,044
Fair Value, Measurements, Recurring
Assets:
Equity securities with readily determinable fair values		4,461,000	3,213,000
Equity securities measured at net asset value	[1]	334,000	271,000
Securities measured at net asset value	[1],[2]	109,000	111,000
Other investments		80,000	63,000
Other assets		71,000
Total assets measured at fair value		59,419,000	56,422,000
Liabilities:
Trading securities sold, not yet purchased		5,703,000	6,467,000
Long-term debt	[3]	2,876,000	2,680,000
Other short-term borrowings	[3]	153,000
Other liabilities		71,000
Total liabilities measured at fair value		23,721,000	22,043,000
Fair Value, Measurements, Recurring | Interest rate contracts
Assets:
Assets, derivatives		8,668,000	8,374,000
Liabilities:
Liabilities, derivatives		8,712,000	8,517,000
Fair Value, Measurements, Recurring | Foreign exchange contracts
Assets:
Assets, derivatives		5,612,000	4,222,000
Liabilities:
Liabilities, derivatives		5,582,000	4,013,000
Fair Value, Measurements, Recurring | Equity-related contracts
Assets:
Assets, derivatives		340,000	145,000
Liabilities:
Liabilities, derivatives		394,000	197,000
Fair Value, Measurements, Recurring | Credit-related contracts
Assets:
Assets, derivatives		214,000	144,000
Liabilities:
Liabilities, derivatives		180,000	126,000
Fair Value, Measurements, Recurring | Other contracts
Assets:
Assets, derivatives		40,000	47,000
Liabilities:
Liabilities, derivatives		50,000	43,000
Fair Value, Measurements, Recurring | Japanese government bonds
Assets:
Assets, trading securities	[2]	1,628,000	1,194,000
Available-for-sale securities		10,974,000	16,449,000
Fair Value, Measurements, Recurring | Japanese local government bonds
Assets:
Assets, trading securities	[2]	135,000	138,000
Available-for-sale securities		584,000	555,000
Fair Value, Measurements, Recurring | U.S. Treasury bonds and federal agency securities
Assets:
Assets, trading securities	[2]	5,002,000	3,294,000
Available-for-sale securities		147,000	376,000
Fair Value, Measurements, Recurring | Other foreign government bonds
Assets:
Assets, trading securities	[2]	1,572,000	1,444,000
Available-for-sale securities		2,045,000	1,308,000
Fair Value, Measurements, Recurring | Agency mortgage-backed securities
Assets:
Assets, trading securities	[2]	6,717,000	5,309,000
Available-for-sale securities		477,000	522,000
Fair Value, Measurements, Recurring | Residential mortgage-backed securities
Assets:
Available-for-sale securities		31,000	47,000
Fair Value, Measurements, Recurring | Commercial mortgage-backed securities
Assets:
Available-for-sale securities		804,000	862,000
Fair Value, Measurements, Recurring | Certificates of deposit and commercial paper
Assets:
Assets, trading securities	[2]	351,000	516,000
Fair Value, Measurements, Recurring | Corporate bonds and other debt securities
Assets:
Assets, trading securities	[2],[4]	3,397,000	2,453,000
Fair Value, Measurements, Recurring | Equity securities
Assets:
Assets, trading securities	[2]	2,973,000	2,250,000
Fair Value, Measurements, Recurring | Japanese corporate bonds and other debt securities
Assets:
Available-for-sale securities		1,833,000	2,109,000
Fair Value, Measurements, Recurring | Foreign corporate bonds and other debt securities
Assets:
Available-for-sale securities		818,000	1,006,000
Fair Value, Measurements, Recurring | Level 1
Assets:
Equity securities with readily determinable fair values		4,165,000	3,052,000
Other investments		1,000
Other assets		3,000
Total assets measured at fair value		24,489,000	25,414,000
Liabilities:
Trading securities sold, not yet purchased		3,445,000	2,954,000
Other liabilities		3,000
Total liabilities measured at fair value		3,580,000	3,254,000
Fair Value, Measurements, Recurring | Level 1 | Interest rate contracts
Assets:
Assets, derivatives		14,000	218,000
Liabilities:
Liabilities, derivatives		14,000	244,000
Fair Value, Measurements, Recurring | Level 1 | Equity-related contracts
Assets:
Assets, derivatives		79,000	39,000
Liabilities:
Liabilities, derivatives		105,000	46,000
Fair Value, Measurements, Recurring | Level 1 | Other contracts
Assets:
Assets, derivatives		21,000	15,000
Liabilities:
Liabilities, derivatives		13,000	10,000
Fair Value, Measurements, Recurring | Level 1 | Japanese government bonds
Assets:
Assets, trading securities	[2]	1,623,000	1,187,000
Available-for-sale securities		10,562,000	15,771,000
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury bonds and federal agency securities
Assets:
Assets, trading securities	[2]	3,534,000	1,917,000
Available-for-sale securities		147,000	376,000
Fair Value, Measurements, Recurring | Level 1 | Other foreign government bonds
Assets:
Assets, trading securities	[2]	676,000	658,000
Available-for-sale securities		922,000	322,000
Fair Value, Measurements, Recurring | Level 1 | Equity securities
Assets:
Assets, trading securities	[2]	2,743,000	1,859,000
Fair Value, Measurements, Recurring | Level 2
Assets:
Equity securities with readily determinable fair values		296,000	161,000
Other assets		68,000
Total assets measured at fair value		33,961,000	30,162,000
Liabilities:
Trading securities sold, not yet purchased		2,258,000	3,513,000
Long-term debt	[3]	2,450,000	1,844,000
Other short-term borrowings	[3]	153,000
Other liabilities		68,000
Total liabilities measured at fair value		19,610,000	17,863,000
Fair Value, Measurements, Recurring | Level 2 | Interest rate contracts
Assets:
Assets, derivatives		8,640,000	8,103,000
Liabilities:
Liabilities, derivatives		8,697,000	8,271,000
Fair Value, Measurements, Recurring | Level 2 | Foreign exchange contracts
Assets:
Assets, derivatives		5,610,000	4,200,000
Liabilities:
Liabilities, derivatives		5,571,000	4,005,000
Fair Value, Measurements, Recurring | Level 2 | Equity-related contracts
Assets:
Assets, derivatives		255,000	73,000
Liabilities:
Liabilities, derivatives		213,000	91,000
Fair Value, Measurements, Recurring | Level 2 | Credit-related contracts
Assets:
Assets, derivatives		213,000	143,000
Liabilities:
Liabilities, derivatives		174,000	124,000
Fair Value, Measurements, Recurring | Level 2 | Other contracts
Assets:
Assets, derivatives		9,000	12,000
Liabilities:
Liabilities, derivatives		26,000	15,000
Fair Value, Measurements, Recurring | Level 2 | Japanese government bonds
Assets:
Assets, trading securities	[2]	5,000	7,000
Available-for-sale securities		412,000	678,000
Fair Value, Measurements, Recurring | Level 2 | Japanese local government bonds
Assets:
Assets, trading securities	[2]	135,000	138,000
Available-for-sale securities		584,000	555,000
Fair Value, Measurements, Recurring | Level 2 | U.S. Treasury bonds and federal agency securities
Assets:
Assets, trading securities	[2]	1,468,000	1,377,000
Fair Value, Measurements, Recurring | Level 2 | Other foreign government bonds
Assets:
Assets, trading securities	[2]	897,000	786,000
Available-for-sale securities		1,122,000	986,000
Fair Value, Measurements, Recurring | Level 2 | Agency mortgage-backed securities
Assets:
Assets, trading securities	[2]	6,717,000	5,309,000
Available-for-sale securities		477,000	522,000
Fair Value, Measurements, Recurring | Level 2 | Residential mortgage-backed securities
Assets:
Available-for-sale securities		24,000	34,000
Fair Value, Measurements, Recurring | Level 2 | Commercial mortgage-backed securities
Assets:
Available-for-sale securities		801,000	862,000
Fair Value, Measurements, Recurring | Level 2 | Certificates of deposit and commercial paper
Assets:
Assets, trading securities	[2]	351,000	516,000
Fair Value, Measurements, Recurring | Level 2 | Corporate bonds and other debt securities
Assets:
Assets, trading securities	[2],[4]	3,208,000	2,406,000
Fair Value, Measurements, Recurring | Level 2 | Equity securities
Assets:
Assets, trading securities	[2]	209,000	370,000
Fair Value, Measurements, Recurring | Level 2 | Japanese corporate bonds and other debt securities
Assets:
Available-for-sale securities		1,666,000	2,008,000
Fair Value, Measurements, Recurring | Level 2 | Foreign corporate bonds and other debt securities
Assets:
Available-for-sale securities		795,000	916,000
Fair Value, Measurements, Recurring | Level 3
Assets:
Other investments		80,000	63,000
Total assets measured at fair value		525,000	464,000
Liabilities:
Trading securities sold, not yet purchased		0
Long-term debt	[3]	427,000	836,000
Total liabilities measured at fair value		531,000	926,000
Fair Value, Measurements, Recurring | Level 3 | Interest rate contracts
Assets:
Assets, derivatives		14,000	53,000
Liabilities:
Liabilities, derivatives		1,000	2,000
Fair Value, Measurements, Recurring | Level 3 | Foreign exchange contracts
Assets:
Assets, derivatives		2,000	22,000
Liabilities:
Liabilities, derivatives		11,000	8,000
Fair Value, Measurements, Recurring | Level 3 | Equity-related contracts
Assets:
Assets, derivatives		6,000	33,000
Liabilities:
Liabilities, derivatives		76,000	60,000
Fair Value, Measurements, Recurring | Level 3 | Credit-related contracts
Assets:
Assets, derivatives		1,000	1,000
Liabilities:
Liabilities, derivatives		6,000	2,000
Fair Value, Measurements, Recurring | Level 3 | Other contracts
Assets:
Assets, derivatives		10,000	20,000
Liabilities:
Liabilities, derivatives		10,000	18,000
Fair Value, Measurements, Recurring | Level 3 | Residential mortgage-backed securities
Assets:
Available-for-sale securities		8,000	13,000
Fair Value, Measurements, Recurring | Level 3 | Commercial mortgage-backed securities
Assets:
Available-for-sale securities		4,000
Fair Value, Measurements, Recurring | Level 3 | Corporate bonds and other debt securities
Assets:
Assets, trading securities	[2],[4]	189,000	47,000
Fair Value, Measurements, Recurring | Level 3 | Equity securities
Assets:
Assets, trading securities	[2]	21,000	21,000
Fair Value, Measurements, Recurring | Level 3 | Japanese corporate bonds and other debt securities
Assets:
Available-for-sale securities		167,000	101,000
Fair Value, Measurements, Recurring | Level 3 | Foreign corporate bonds and other debt securities
Assets:
Available-for-sale securities		¥ 23,000	¥ 90,000
[1]In accordance with ASC 820, certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented for these classes of assets are intended to permit the reconciliation of the fair value hierarchy to the amounts presented in the statements of financial position. The amounts of unfunded commitments related to these investments at March 31, 2023 and 2024 were ¥52 billion and ¥41 billion, respectively.[2]Trading securities include foreign currency denominated securities for which the MHFG Group elected the fair value option.[3]Amounts represent items for which the Group elected the fair value option or for which it applied the practicability exception.[4]The amount includes CLO and convertible bonds, which are classified in Level 3.

Fair Value (Summary of Assets_2

Fair Value (Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis, Including Fair Value Option Elected) (Parenthetical) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2024	Mar. 31, 2023
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unfunded commitments	¥ 41	¥ 52

Fair Value (Reconciliation for

Fair Value (Reconciliation for All Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3) (Detail) - JPY (¥) ¥ in Billions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Trading securities sold, not yet purchased
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Purchases			¥ (1)
Sales			1
Long-term debt
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		¥ 836	794
Gains (losses) in Earnings	[1]	(57)	29
Gains (losses) in OCI	[2]	(14)	10
Transfers into Level 3		1	1
Transfers out of level 3		(285)	(2)
Issuances		276	323
Settlements		(472)	(241)
Ending Balance		427	836
Change in unrealized gain (losses) still held	[3]	(11)	60
Trading securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers into Level 3		15	13
Transfers out of level 3		(7)	(15)
Trading securities | Residential mortgage- backed securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance			8
Gains (losses) in Earnings	[4]		(1)
Sales			(6)
Settlements			(1)
Trading securities | Corporate bonds and other debt securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		47	71
Gains (losses) in Earnings	[4]	12	4
Transfers into Level 3		15	13
Transfers out of level 3		(7)	(15)
Purchases		214	104
Sales		(59)	(46)
Settlements		(34)	(84)
Ending Balance		189	47
Change in unrealized gain (losses) still held	[3]	9
Trading securities | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		21	28
Purchases		3	2
Sales		(1)	(6)
Settlements		(1)	(3)
Ending Balance		21	21
Change in unrealized gain (losses) still held	[3]		(1)
Derivative financial instruments assets
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers out of level 3		(33)
Derivative financial instruments assets | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[5]	51	22
Gains (losses) in Earnings	[4],[5]	(44)	31
Transfers out of level 3	[5]	(32)
Settlements	[5]	38	(2)
Ending Balance	[5]	13	51
Change in unrealized gain (losses) still held	[3],[5]	8	(22)
Derivative financial instruments assets | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[5]	14	32
Gains (losses) in Earnings	[4],[5]	(8)	(5)
Transfers out of level 3	[5]	0
Settlements	[5]	(15)	(13)
Ending Balance	[5]	(9)	14
Change in unrealized gain (losses) still held	[3],[5]	(10)	(6)
Derivative financial instruments assets | Equity-related contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[5]	(27)	(14)
Gains (losses) in Earnings	[4],[5]	(62)	(26)
Transfers out of level 3	[5]	(1)
Settlements	[5]	20	13
Ending Balance	[5]	(70)	(27)
Change in unrealized gain (losses) still held	[3],[5]	(37)	(107)
Derivative financial instruments assets | Credit-related contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[5]	(1)	1
Gains (losses) in Earnings	[4],[5]	(6)	(1)
Transfers out of level 3	[5]	0
Settlements	[5]	2	(1)
Ending Balance	[5]	(5)	(1)
Change in unrealized gain (losses) still held	[3],[5]	(3)	(5)
Derivative financial instruments assets | Other contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[5]	2
Gains (losses) in Earnings	[4],[5]	(1)	2
Transfers out of level 3	[5]	0
Settlements	[5]	(1)
Ending Balance	[5]		2
Change in unrealized gain (losses) still held	[3],[5]	(1)	2
Available-for-sale securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers out of level 3		(2)	(54)
Available-for-sale securities | Residential mortgage- backed securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		13	18
Purchases		0
Sales		(2)
Settlements		(3)	(5)
Ending Balance		8	13
Available-for-sale securities | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Purchases		4
Ending Balance		4
Available-for-sale securities | Japanese corporate bonds and other debt securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		101	315
Gains (losses) in OCI	[2]	9	3
Purchases		106	25
Settlements		(49)	(242)
Ending Balance		167	101
Change in unrealized gain (losses) still held	[3]	12	8
Available-for-sale securities | Foreign corporate bonds and other debt securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		90	117
Gains (losses) in Earnings	[6]	8
Gains (losses) in OCI	[2]		1
Transfers out of level 3		(2)	(54)
Purchases		10	63
Settlements		(82)	(37)
Ending Balance		23	90
Change in unrealized gain (losses) still held	[3]	(1)
Available-for-sale securities | Other investments
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		63	56
Gains (losses) in Earnings	[6]	1	3
Transfers out of level 3			(1)
Purchases		47	36
Settlements		(31)	(31)
Ending Balance		¥ 80	63
Change in unrealized gain (losses) still held	[3]		¥ 1
[1]Gains (losses) in Earnings are reported in Other noninterest income (expenses).[2]Gains (losses) in OCI are reported in Other comprehensive income (loss).[3]Amounts represent total gains or losses recognized in earnings and other comprehensive income (loss) during the period. These gains or losses were attributable to the change in fair value relating to assets and liabilities classified as Level 3 that were still held at March 31, 2023 and 2024. The amounts of unrealized gains (losses) in other comprehensive income (loss) are related to Available-for-sale securities and Long-term debt, which were ¥8 billion and ¥11 billion, respectively, at March 31, 2023, and ¥11 billion and ¥(5) billion, respectively, at March 31, 2024.[4]Gains (losses) in Earnings are reported in Trading account gains (losses)—net, Foreign exchange gains (losses)—net or Other noninterest income (expenses).[5]Total Level 3 derivative exposures have been netted on the table for presentation purposes only.[6]Gains (losses) in Earnings are reported in Investment gains (losses)—net.

Fair Value (Reconciliation fo_2

Fair Value (Reconciliation for All Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3) (Parenthetical) (Detail) - JPY (¥) ¥ in Billions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Fair Value Disclosures [Abstract]
Unrealized gains (losses) in OCI related to Available-for-sale securities	¥ 11	¥ 8
Unrealized gains (losses) in OCI related to Long-term debt	¥ (5)	¥ 11

Fair Value (Quantitative Inform

Fair Value (Quantitative Information about Significant Unobservable Inputs Related to Material Classes of Level 3 Assets and Liabilities) (Detail)		Mar. 31, 2024 JPY (¥)	Mar. 31, 2023 JPY (¥)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt		¥ 2,876,287,000,000	¥ 2,680,164,000,000
Trading securities and Available-for- sale | Residential mortgage-backed securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		8,000,000,000	13,000,000,000
Trading securities and Available-for- sale | Commercial mortgage-backed securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		4,000,000,000
Trading securities and Available-for- sale | Corporate bonds and other debt securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		380,000,000,000	238,000,000,000
Derivative Financial Instruments | Other contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments		0	2,000,000,000
Derivative Financial Instruments | Interest rate contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments		13,000,000,000	51,000,000,000
Derivative Financial Instruments | Foreign exchange contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments		(9,000,000,000)	14,000,000,000
Derivative Financial Instruments | Equity-related contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments		(70,000,000,000)	(27,000,000,000)
Derivative Financial Instruments | Credit-related contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments		(5,000,000,000)	(1,000,000,000)
Long-term debt
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt		¥ 427,000,000,000	¥ 836,000,000,000
Minimum | Derivative Financial Instruments | Credit-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1]	0	0.1
Minimum | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1]	0	0.1
Minimum | Measurement Input, Prepayment Rate [Member] | Trading securities and Available-for- sale | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		0.4	0.2
Minimum | Measurement Input, Prepayment Rate [Member] | Trading securities and Available-for- sale | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[2]	3.2	21.7
Minimum | Measurement Input, Default Rate [Member] | Trading securities and Available-for- sale | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities			0
Minimum | Measurement Input, Default Rate [Member] | Trading securities and Available-for- sale | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[2]	0.4	0.2
Minimum | Measurement Input Recovery Rate [Member] | Trading securities and Available-for- sale | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		100	100
Minimum | Measurement Input Recovery Rate [Member] | Trading securities and Available-for- sale | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[2]	36.9	40.5
Minimum | Measurement Input, Discount Rate [Member] | Trading securities and Available-for- sale | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		30	30
Minimum | Measurement Input, Discount Rate [Member] | Trading securities and Available-for- sale | Commercial mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		158.7
Minimum | Measurement Input, Discount Rate [Member] | Trading securities and Available-for- sale | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[2]	56.9	98.8
Minimum | Measurement Input, Discount Rate1 [Member] | Trading securities and Available-for- sale | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[3]	38.2	3.5
Minimum | Measurement Input, IR - IR correlation [Member] | Derivative Financial Instruments | Interest rate contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1]	23.2	23.2
Minimum | Measurement Input, IR - IR correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1]	23.2	23.2
Minimum | Measurement Input, FX - IR correlation [Member] | Derivative Financial Instruments | Foreign exchange contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1]	13.8	5.5
Minimum | Measurement Input, FX - IR correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1]	5.5	5.5
Minimum | Measurement Input, FX - FX correlation [Member] | Derivative Financial Instruments | Foreign exchange contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1]	39	39
Minimum | Measurement Input, FX - FX correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1]	39	39
Minimum | Measurement Input, Equity - IR correlation [Member] | Derivative Financial Instruments | Equity-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1]	25	25
Minimum | Measurement Input, Equity - IR correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1]	25	25
Minimum | Measurement Input, Equity - FX correlation [Member] | Derivative Financial Instruments | Equity-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1]	15	0
Minimum | Measurement Input, Equity - FX correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1]	(17.8)	(16.3)
Minimum | Measurement Input, Equity volatility [Member] | Derivative Financial Instruments | Equity-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1]	9.8	10.3
Minimum | Measurement Input, Equity volatility [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1]	9.8	5.9
Minimum | Measurement Input, Credit correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1]		47.6
Minimum | Measurement Input, Equity correlation [Member] | Derivative Financial Instruments | Equity-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1]		73.9
Minimum | Measurement Input, Equity correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1]	32.2	3.2
Minimum | Measurement Input Commodity Volatility [Member] | Derivative Financial Instruments | Other contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1]	0	20
Maximum | Derivative Financial Instruments | Credit-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1]	6.4	12.2
Maximum | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1]	9.5	13.1
Maximum | Measurement Input, Prepayment Rate [Member] | Trading securities and Available-for- sale | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		6.2	17.6
Maximum | Measurement Input, Prepayment Rate [Member] | Trading securities and Available-for- sale | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[2]	3.2	21.7
Maximum | Measurement Input, Default Rate [Member] | Trading securities and Available-for- sale | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities			2.2
Maximum | Measurement Input, Default Rate [Member] | Trading securities and Available-for- sale | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[2]	0.4	0.2
Maximum | Measurement Input Recovery Rate [Member] | Trading securities and Available-for- sale | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		100	100
Maximum | Measurement Input Recovery Rate [Member] | Trading securities and Available-for- sale | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[2]	36.9	40.5
Maximum | Measurement Input, Discount Rate [Member] | Trading securities and Available-for- sale | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		65	167.1
Maximum | Measurement Input, Discount Rate [Member] | Trading securities and Available-for- sale | Commercial mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		291.4
Maximum | Measurement Input, Discount Rate [Member] | Trading securities and Available-for- sale | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[2]	56.9	209.9
Maximum | Measurement Input, Discount Rate1 [Member] | Trading securities and Available-for- sale | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[3]	187.7	171.2
Maximum | Measurement Input, IR - IR correlation [Member] | Derivative Financial Instruments | Interest rate contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1]	100	100
Maximum | Measurement Input, IR - IR correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1]	100	100
Maximum | Measurement Input, FX - IR correlation [Member] | Derivative Financial Instruments | Foreign exchange contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1]	72.5	58.2
Maximum | Measurement Input, FX - IR correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1]	72.5	58.2
Maximum | Measurement Input, FX - FX correlation [Member] | Derivative Financial Instruments | Foreign exchange contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1]	64.7	64.7
Maximum | Measurement Input, FX - FX correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1]	64.7	64.7
Maximum | Measurement Input, Equity - IR correlation [Member] | Derivative Financial Instruments | Equity-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1]	25	25
Maximum | Measurement Input, Equity - IR correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1]	25	25
Maximum | Measurement Input, Equity - FX correlation [Member] | Derivative Financial Instruments | Equity-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1]	60	60
Maximum | Measurement Input, Equity - FX correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1]	93.3	93.3
Maximum | Measurement Input, Equity volatility [Member] | Derivative Financial Instruments | Equity-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1]	121.8	95.4
Maximum | Measurement Input, Equity volatility [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1]	70.7	180.8
Maximum | Measurement Input, Credit correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1]		100
Maximum | Measurement Input, Equity correlation [Member] | Derivative Financial Instruments | Equity-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1]		100
Maximum | Measurement Input, Equity correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1]	100	100
Maximum | Measurement Input Commodity Volatility [Member] | Derivative Financial Instruments | Other contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1]	27.7	54.5
Weighted Average | Derivative Financial Instruments | Credit-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1],[4]	1.4	2.1
Weighted Average | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1],[4]	1.4	2.3
Weighted Average | Measurement Input, Prepayment Rate [Member] | Trading securities and Available-for- sale | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[4]	3.8	4.4
Weighted Average | Measurement Input, Prepayment Rate [Member] | Trading securities and Available-for- sale | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[2],[4]	3.2	21.7
Weighted Average | Measurement Input, Default Rate [Member] | Trading securities and Available-for- sale | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[4]		0.2
Weighted Average | Measurement Input, Default Rate [Member] | Trading securities and Available-for- sale | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[2],[4]	0.4	0.2
Weighted Average | Measurement Input Recovery Rate [Member] | Trading securities and Available-for- sale | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[4]	100	100
Weighted Average | Measurement Input Recovery Rate [Member] | Trading securities and Available-for- sale | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[2],[4]	36.9	40.5
Weighted Average | Measurement Input, Discount Rate [Member] | Trading securities and Available-for- sale | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[4]	40.1	47
Weighted Average | Measurement Input, Discount Rate [Member] | Trading securities and Available-for- sale | Commercial mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[4]	234.2
Weighted Average | Measurement Input, Discount Rate [Member] | Trading securities and Available-for- sale | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[2],[4]	56.9	116.2
Weighted Average | Measurement Input, Discount Rate1 [Member] | Trading securities and Available-for- sale | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[3],[4]	63.6	20.1
Weighted Average | Measurement Input, IR - IR correlation [Member] | Derivative Financial Instruments | Interest rate contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1],[4]	71.4	75
Weighted Average | Measurement Input, IR - IR correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1],[4]	71.4	75
Weighted Average | Measurement Input, FX - IR correlation [Member] | Derivative Financial Instruments | Foreign exchange contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1],[4]	29.9	39.9
Weighted Average | Measurement Input, FX - IR correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1],[4]	29.9	39.9
Weighted Average | Measurement Input, FX - FX correlation [Member] | Derivative Financial Instruments | Foreign exchange contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1],[4]	51.9	51.9
Weighted Average | Measurement Input, FX - FX correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1],[4]	51.9	51.9
Weighted Average | Measurement Input, Equity - IR correlation [Member] | Derivative Financial Instruments | Equity-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1],[4]	25	25
Weighted Average | Measurement Input, Equity - IR correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1],[4]	25	25
Weighted Average | Measurement Input, Equity - FX correlation [Member] | Derivative Financial Instruments | Equity-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1],[4]	60	33.7
Weighted Average | Measurement Input, Equity - FX correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1],[4]	0	0
Weighted Average | Measurement Input, Equity volatility [Member] | Derivative Financial Instruments | Equity-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1],[4]	42.1	44.1
Weighted Average | Measurement Input, Equity volatility [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1],[4]	25.8	34.1
Weighted Average | Measurement Input, Credit correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1],[4]		68.3
Weighted Average | Measurement Input, Equity correlation [Member] | Derivative Financial Instruments | Equity-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1],[4]		96.7
Weighted Average | Measurement Input, Equity correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[1],[4]	87.3	90.8
Weighted Average | Measurement Input Commodity Volatility [Member] | Derivative Financial Instruments | Other contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[1],[4]	23.7	39.8
[1]Internal valuation model includes discounted cash flow models and the Black-Scholes option pricing model.[2]These inputs are mainly used for determining the fair values of securitization products such as CDO, CLO and ABS, other than RMBS and CMBS.[3]This input is mainly used for determining the fair values of Japanese corporate bonds and foreign corporate bonds.[4]Averages are calculated by weighting each input by the relative fair value of the respective financial instruments except for derivative related inputs where medians are used.

Fair Value (Summary of Assets_3

Fair Value (Summary of Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis) (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Assets:
Equity securities (without readily determinable fair values)	¥ 357,938	¥ 207,743	¥ 207,407
Fair Value, Measurements, Nonrecurring
Assets:
Loans	101,000	97,000
Loans held-for-sale	95,000	216,000
Equity securities (without readily determinable fair values)	34,000	4,000
Other investments		94,000
Premises and equipment—net		1,000
Total assets measured at fair value	383,000	412,000
Fair Value, Measurements, Nonrecurring | Aggregate cost
Assets:
Loans	187,000	165,000
Loans held-for-sale	150,000	282,000
Equity securities (without readily determinable fair values)	39,000	5,000
Other investments	199,000	122,000
Premises and equipment—net	6,000	2,000
Intangible assets	1,000
Total assets measured at fair value	581,000	576,000
Fair Value, Measurements, Nonrecurring | Level 1
Assets:
Loans	0
Other investments	153,000	93,000
Total assets measured at fair value	0	93,000
Fair Value, Measurements, Nonrecurring | Level 2
Assets:
Loans	0
Loans held-for-sale	2,000	16,000
Equity securities (without readily determinable fair values)	2,000	4,000
Total assets measured at fair value	4,000	20,000
Fair Value, Measurements, Nonrecurring | Level 3
Assets:
Loans	101,000	97,000
Loans held-for-sale	94,000	200,000
Equity securities (without readily determinable fair values)	31,000	0
Other investments	153,000	1,000
Premises and equipment—net		1,000
Total assets measured at fair value	¥ 379,000	¥ 299,000

Fair Value (Carrying Amounts an

Fair Value (Carrying Amounts and Fair Values of Certain Financial Instruments, Excluding Financial Instruments Carried at Fair Value on a Recurring Basis and Those outside Scope of ASC 825) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2024	Mar. 31, 2023
Financial liabilities:
Long-term debt		¥ 2,876,287	¥ 2,680,164
Carrying amount
Financial assets:
Cash and due from banks, interest-bearing deposits in other banks, call loans and funds sold, and receivables under resale agreements and securities borrowing transactions		98,392,000	83,226,000
Investments		4,048,000	2,050,000
Loans, net of allowance	[1]	97,519,000	93,291,000
Financial liabilities:
Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions		78,030,000	64,618,000
Interest-bearing deposits		135,447,000	128,756,000
Due to trust accounts		246,000	749,000
Other short-term borrowings		3,492,000	3,397,000
Long-term debt		13,380,000	12,246,000
Estimated fair value
Financial assets:
Cash and due from banks, interest-bearing deposits in other banks, call loans and funds sold, and receivables under resale agreements and securities borrowing transactions		98,392,000	83,226,000
Investments		3,863,000	1,915,000
Loans, net of allowance	[1]	98,868,000	94,605,000
Financial liabilities:
Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions		78,030,000	64,618,000
Interest-bearing deposits		135,397,000	128,718,000
Due to trust accounts		246,000	749,000
Other short-term borrowings		3,492,000	3,397,000
Long-term debt		13,031,000	11,719,000
Estimated fair value | Level 1
Financial assets:
Cash and due from banks, interest-bearing deposits in other banks, call loans and funds sold, and receivables under resale agreements and securities borrowing transactions		72,026,000	66,498,000
Investments		512,000	800,000
Loans, net of allowance	[1]	0
Financial liabilities:
Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions		0
Interest-bearing deposits		0
Due to trust accounts		0
Other short-term borrowings		0
Long-term debt		0
Estimated fair value | Level 2
Financial assets:
Cash and due from banks, interest-bearing deposits in other banks, call loans and funds sold, and receivables under resale agreements and securities borrowing transactions		26,366,000	16,728,000
Investments		3,351,000	1,115,000
Loans, net of allowance	[1]	0
Financial liabilities:
Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions		78,030,000	64,618,000
Interest-bearing deposits		135,397,000	128,718,000
Due to trust accounts		246,000	749,000
Other short-term borrowings		3,492,000	3,397,000
Long-term debt		11,681,000	10,315,000
Estimated fair value | Level 3
Financial assets:
Cash and due from banks, interest-bearing deposits in other banks, call loans and funds sold, and receivables under resale agreements and securities borrowing transactions		0
Investments		0
Loans, net of allowance	[1]	98,868,000	94,605,000
Financial liabilities:
Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions		0
Interest-bearing deposits		0
Due to trust accounts		0
Other short-term borrowings		0
Long-term debt		¥ 1,350,000	¥ 1,404,000
[1]Loans, net of allowance include items measured at fair value on a nonrecurring basis.

Offsetting of Financial Asset_3

Offsetting of Financial Assets and Financial Liabilities (Information of Offsetting of Financial Assets and Financial Liabilities) (Detail) - JPY (¥) ¥ in Billions		Mar. 31, 2024	Mar. 31, 2023
Offsetting Financial Assets And Financial Liabilities [Line Items]
Derivative assets, Gross amounts recognized	[1]	¥ 14,874	¥ 12,932
Derivative assets, Gross amounts offset on the balance sheet	[1]	0	0
Derivative assets, Net amounts presented on the balance sheet	[1],[2],[3]	14,874	12,932
Derivative assets, Amounts not offset on the balance sheet, Financial instruments	[1],[4],[5]	(11,525)	(10,476)
Derivative assets, Amounts not offset on the balance sheet, Cash collateral	[1],[4]	(1,065)	(821)
Derivative assets, Net amounts	[1]	2,284	1,635
Receivables under resale agreements, Gross amounts recognized	[1]	20,535	11,695
Receivables under resale agreements, Gross amounts offset on the balance sheet	[1]	0	0
Receivables under resale agreements, Net amounts presented on the balance sheet	[1],[2],[6]	20,535	11,695
Receivables under resale agreements, Amounts not offset on the balance sheet, Financial instruments	[1],[4],[5]	(19,431)	(10,565)
Receivables under resale agreements, Amounts not offset on the balance sheet, Cash collateral	[1],[4]	0	0
Receivables under resale agreements, Net amounts	[1]	1,103	1,130
Receivables under securities borrowing transactions, Gross amounts recognized	[1]	2,352	1,892
Receivables under securities borrowing transactions, Gross amounts offset on the balance sheet	[1]	0	0
Receivables under securities borrowing transactions, Net amounts presented on the balance sheet	[1],[2],[7]	2,352	1,892
Receivables under securities borrowing transactions, Amounts not offset on the balance sheet, Financial instruments	[1],[4],[5]	(2,261)	(1,866)
Receivables under securities borrowing transactions, Amounts not offset on the balance sheet, Cash collateral	[1],[4]	0	0
Receivables under securities borrowing transactions, Net amounts	[1]	91	26
Financial assets, Gross amounts recognized, Total	[1]	37,761	26,519
Financial assets, Gross amounts offset on the balance sheet, Total	[1]	0	0
Financial assets, Net amounts presented on the balance sheet, Total	[1],[2]	37,761	26,519
Financial assets, Amounts not offset on the balance sheet, Financial instruments, Total	[1],[4],[5]	(33,217)	(22,907)
Financial assets, Amounts not offset on the balance sheet, Cash collateral, Total	[1],[4]	(1,065)	(821)
Financial assets, Net amounts, Total	[1]	3,478	2,791
Derivative liabilities, Gross amounts recognized	[1]	14,918	12,896
Derivative liabilities, Gross amounts offset on the balance sheet	[1]	0	0
Derivative liabilities, Net amounts presented on the balance sheet	[1],[2],[3]	14,918	12,896
Derivative liabilities, Amounts not offset on the balance sheet, Financial instruments	[1],[4],[5]	(10,941)	(10,141)
Derivative liabilities, Amounts not offset on the balance sheet, Cash collateral	[1],[4]	(1,137)	(843)
Derivative liabilities, Net amounts	[1]	2,840	1,912
Payables under repurchase agreements, Gross amounts recognized	[1]	38,105	25,737
Payables under repurchase agreements, Gross amounts offset on the balance sheet	[1]	0	0
Payables under repurchase agreements, Net amounts presented on the balance sheet	[1],[2],[6]	38,105	25,737
Payables under repurchase agreements, Amounts not offset on the balance sheet, Financial instruments	[1],[4],[5]	(36,842)	(25,113)
Payables under repurchase agreements, Amounts not offset on the balance sheet, Cash collateral	[1],[4]	0	0
Payables under repurchase agreements, Net amounts	[1]	1,262	624
Payables under securities lending transactions, Gross amounts recognized	[1]	1,350	886
Payables under securities lending transactions, Gross amounts offset on the balance sheet	[1]	0	0
Payables under securities lending transactions, Net amounts presented on the balance sheet	[1],[2],[7]	1,350	886
Payables under securities lending transactions, Amounts not offset on the balance sheet, Financial instruments	[1],[4],[5]	(1,298)	(755)
Payables under securities lending transactions, Amounts not offset on the balance sheet, Cash collateral	[1],[4]	0	0
Payables under securities lending transactions, Net amounts	[1]	52	131
Other liabilities, Gross amounts recognized	[1],[8]	71
Other liabilities, Gross amounts offset on the balance sheet	[1],[8]	0
Other liabilities, Net amounts presented on the balance sheet	[1],[2],[8]	71
Other liabilities, Amounts not offset on the balance sheet, Financial instruments	[1],[4],[5],[8]	(60)
Other liabilities, Amounts not offset on the balance sheet, Cash collateral	[1],[4],[8]	0
Other liabilities, Net amounts	[1],[8]	11
Financial liabilities, Gross amounts recognized, Total	[1]	54,444	39,519
Financial liabilities, Gross amounts offset on the balance sheet, Total	[1]	0	0
Financial liabilities, Net amounts presented on the balance sheet, Total	[1],[2]	54,444	39,519
Financial liabilities, Amounts not offset on the balance sheet, Financial instruments, Total	[1],[4],[5]	(49,142)	(36,009)
Financial liabilities, Amounts not offset on the balance sheet, Cash collateral, Total	[1],[4]	(1,137)	(843)
Financial liabilities, Net amounts, Total	[1]	¥ 4,166	¥ 2,667
[1]Amounts relating to master netting arrangements or similar agreements where the MHFG Group does not have the legal right of set-off or where uncertainty exists as to the enforceability of these agreements are excluded. For derivatives, the table includes amounts relating to over-the-counter (“OTC”) and OTC-cleared derivatives that are subject to enforceable master netting arrangements or similar agreements.[2]Derivative assets and liabilities are recorded in Trading account assets and Trading account liabilities, respectively.[3]The amounts of derivative assets and liabilities subject to enforceable master netting arrangements or similar agreements were ¥12,574 billion and ¥12,432 billion, respectively, at March 31, 2023, and ¥13,930 billion and ¥13,933 billion, respectively, at March 31, 2024.[4]Amounts do not exceed the net amounts presented on the balance sheet and do not include the effect of overcollateralization, where it exists.[5]For derivatives, amounts include derivative assets or liabilities and securities collateral that are eligible for offsetting under enforceable master netting arrangements or similar agreements.[6]The amounts of Receivables under resale agreements and Payables under repurchase agreements subject to enforceable industry standard master repurchase agreements with netting terms were ¥10,587 billion and ¥25,147 billion, respectively, at March 31, 2023, and ¥19,470 billion and ¥37,042 billion, respectively, at March 31, 2024.[7]The amounts of Receivables under securities borrowing transactions and Payables under securities lending transactions subject to enforceable industry standard master lending agreements with netting terms were ¥1,892 billion and ¥758 billion, respectively, at March 31, 2023, and ¥2,352 billion and ¥1,303 billion, respectively, at March 31, 2024.[8]Amounts relate to transactions where the Group acts as lender in a securities lending agreement and receives securities that can be sold or pledged as collateral. In these transactions, the Group recognizes the securities received at fair value within Other assets and the obligation to return those securities as a liability within Other liabilities.

Offsetting of Financial Asset_4

Offsetting of Financial Assets and Financial Liabilities (Information of Offsetting of Financial Assets and Financial Liabilities) (Parenthetical) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2024	Mar. 31, 2023
Offsetting Financial Assets And Financial Liabilities [Line Items]
Receivables under resale agreement subject to enforceable master netting arrangements	¥ 19,470	¥ 10,587
Payables under repurchase agreement subject to enforceable master netting arrangements	37,042	25,147
Receivables under securities transaction borrowing subject to master netting arrangement	2,352	1,892
Payables under securities transaction lending subject to master netting arragement	1,303	758
Subject To Enforceable Master Netting Arragement [Member]
Offsetting Financial Assets And Financial Liabilities [Line Items]
Derivative assets subject to enforceable master netting arrangements	13,930	12,574
Derivative liabilities subject to enforceable master netting arrangements	¥ 13,933	¥ 12,432

Repurchase Agreements and Sec_3

Repurchase Agreements and Securities Lending Transactions Accounted for as Secured Borrowings (Gross Amounts of Liabilities by Remaining Contractual Maturity) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2024		Mar. 31, 2023
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	¥ 38,105	[1]	¥ 25,737
Securities lending transactions	1,350	[1]	886
Total	39,455		26,623
Overnight and continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	18,661		2,285
Securities lending transactions	1,288		685
Total	19,949		2,970
Up to 30 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	11,040		16,508
Securities lending transactions	19		73
Total	11,058		16,581
31 to 90 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	5,415		5,471
Securities lending transactions	0		0
Total	5,415		5,471
Greater than 90 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	2,989		1,473
Securities lending transactions	44		128
Total	¥ 3,033		¥ 1,601
[1]The above table does not include securities-for-securities lending transactions of ¥71 billion at March 31, 2024, where the MHFG Group acts as lender and receives securities that can be sold or pledged as collateral. In these transactions, the Group recognizes the securities received at fair value within Other assets and the obligation to return those securities as a liability within Other liabilities.

Repurchase Agreements and Sec_4

Repurchase Agreements and Securities Lending Transactions Accounted for as Secured Borrowings (Gross Amounts of Liabilities by Class of Underlying Collateral) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2024		Mar. 31, 2023
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	¥ 38,105	[1]	¥ 25,737
Securities lending transactions	1,350	[1]	886
Japanese government bonds and Japanese local government bonds
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	6,167		6,114
Securities lending transactions	102		102
Foreign government bonds and foreign agency mortgage-backed securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	28,757		17,475
Securities lending transactions	19		73
Commercial Paper and Corporate Bonds
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	913		430
Securities lending transactions	0		0
Equity Securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	1,609		1,491
Securities lending transactions	1,229		711
Other
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	658		227
Securities lending transactions	¥ 0		¥ 0
[1]The above table does not include securities-for-securities lending transactions of ¥71 billion at March 31, 2024, where the MHFG Group acts as lender and receives securities that can be sold or pledged as collateral. In these transactions, the Group recognizes the securities received at fair value within Other assets and the obligation to return those securities as a liability within Other liabilities.

Repurchase Agreements and Sec_5

Repurchase Agreements and Securities Lending Transactions Accounted for as Secured Borrowings (Gross Amounts of Liabilities by Class of Underlying Collateral) (Parenthetical) (Detail) ¥ in Billions	Mar. 31, 2024 JPY (¥)
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Customer securities for which entity has right to sell or repledge fair value	¥ 71	[1],[2]
[1]Amounts relate to transactions where the Group acts as lender in a securities lending agreement and receives securities that can be sold or pledged as collateral. In these transactions, the Group recognizes the securities received at fair value within Other assets and the obligation to return those securities as a liability within Other liabilities.[2]Amounts relating to master netting arrangements or similar agreements where the MHFG Group does not have the legal right of set-off or where uncertainty exists as to the enforceability of these agreements are excluded. For derivatives, the table includes amounts relating to over-the-counter (“OTC”) and OTC-cleared derivatives that are subject to enforceable master netting arrangements or similar agreements.

Related Party Transactions - Su

Related Party Transactions - Summary of financial information of groups equity method investees (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Related Party Transaction [Line Items]
Loans		¥ 98,444,745	¥ 94,175,757
Total assets		272,173,152	248,780,722	¥ 231,550,700
Total liabilities		261,741,965	239,055,588
Total equity		10,431,187	9,725,134	9,442,231
Noncontrolling interests		502,116	809,643
Total interest and dividend income		5,767,000	3,388,791	1,443,941
Total interest expense		4,562,076	2,180,064	374,132
Provision (credit) for credit losses		47,135	93,753	214,408
Net interest income after provision (credit) for credit losses		1,157,788	1,114,974	855,401
Income before income tax expense		1,623,100	69,200	(242,500)
Net income	[1]	1,197,992	34,028	(101,471)
Equity Method Investee
Related Party Transaction [Line Items]
Loans		6,924,000	6,037,000
Total assets		28,447,000	29,367,000
Deposits		2,684,000	6,216,000
Total liabilities		24,829,000	26,506,000
Total equity		3,618,000	2,861,000
Noncontrolling interests		29,000	16,000
Total interest and dividend income		958,000	750,000	625,000
Total interest expense		384,000	239,000	182,000
Provision (credit) for credit losses		83,000	96,000	104,000
Net interest income after provision (credit) for credit losses		490,000	415,000	339,000
Income before income tax expense		394,000	261,000	332,000
Net income		¥ 298,000	¥ 194,000	¥ 246,000
[1]The amounts that have been reclassified out of Accumulated other comprehensive income (loss), net of tax into net income are presented in Note 16 “Accumulated other comprehensive income (loss), net of tax.”

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) ¥ in Millions	12 Months Ended
	Mar. 31, 2024 JPY (¥) Loans	Mar. 31, 2023 JPY (¥) Loans
Related Party Transaction [Line Items]
Number of loans impaired | Loans	0	0
Related party loan	¥ 571,349	¥ 468,344
Related Party
Related Party Transaction [Line Items]
Related party loan	¥ 914,000	¥ 732,000

Business Segment Information -

Business Segment Information - Additional Information (Detail)	12 Months Ended
	Mar. 31, 2024 Segment
Segment Reporting Information [Line Items]
Number of operating segments	5

Business Segment Information (R

Business Segment Information (Reportable Segment Information Derived from Internal Management Reporting Systems, on Basis of Japanese GAAP) (Detail) - JPY (¥) ¥ in Billions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits + Net gains (losses) related to ETFs and others	[1],[2]	¥ 2,672.2	¥ 2,280.2	¥ 2,254.3
General and administrative expenses	[1],[3]	1,681.9	1,473.5	1,414.9
Equity in earnings (losses) of equity method investees—net	[1]	26.2	11.8	25.4
Amortization of goodwill and others	[1]	10.7	11.4	11.6
Net business profits (losses) + Net gains (losses) related to ETFs and others	[1],[4]	1,005.8	807.1	853.1
Fixed assets	[1],[5]	1,864.6	1,678.5	1,697.2
Operating Segments | RBC
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits + Net gains (losses) related to ETFs and others	[1],[2]	749.2	706.5	717.5
General and administrative expenses	[1],[3]	651.1	605.7	617.8
Equity in earnings (losses) of equity method investees—net	[1]	6.9	(18.3)	5.8
Amortization of goodwill and others	[1]	0	2	2.1
Net business profits (losses) + Net gains (losses) related to ETFs and others	[1],[4]	105	80.3	103.4
Fixed assets	[1],[5]	533.8	483.3	486.9
Operating Segments | CIBC
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits + Net gains (losses) related to ETFs and others	[1],[2]	556.3	508.7	499.8
General and administrative expenses	[1],[3]	217.7	202	205.9
Equity in earnings (losses) of equity method investees—net	[1]	7.6	6.3	3.7
Amortization of goodwill and others	[1]	0	0	0
Net business profits (losses) + Net gains (losses) related to ETFs and others	[1],[4]	346.1	312.9	297.4
Fixed assets	[1],[5]	157.1	152.8	161.7
Operating Segments | GCIBC
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits + Net gains (losses) related to ETFs and others	[1],[2]	670.2	627.1	553
General and administrative expenses	[1],[3]	352.4	309.2	286.4
Equity in earnings (losses) of equity method investees—net	[1]	22	20.3	14.3
Amortization of goodwill and others	[1]	2.3	0.7	0.3
Net business profits (losses) + Net gains (losses) related to ETFs and others	[1],[4]	337.4	337.5	280.5
Fixed assets	[1],[5]	197.9	177.7	165.8
Operating Segments | GMC
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits + Net gains (losses) related to ETFs and others	[1],[2]	432.4	314.2	383.8
General and administrative expenses	[1],[3]	307.4	253.4	230.7
Equity in earnings (losses) of equity method investees—net	[1]	0	0	0
Amortization of goodwill and others	[1]	0	0.7	0.8
Net business profits (losses) + Net gains (losses) related to ETFs and others	[1],[4]	125	59.9	152.3
Fixed assets	[1],[5]	90.3	87.3	87.9
Operating Segments | AMC
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits + Net gains (losses) related to ETFs and others	[1],[2]	57.2	54.7	59.4
General and administrative expenses	[1],[3]	36.1	35	33.4
Equity in earnings (losses) of equity method investees—net	[1]	(11.8)	0	1.5
Amortization of goodwill and others	[1]	6.4	6.8	7.2
Net business profits (losses) + Net gains (losses) related to ETFs and others	[1],[4]	2.7	12.8	20.3
Fixed assets	[1],[5]	0	0	0
Others
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits + Net gains (losses) related to ETFs and others	[1],[2],[6]	206.8	68.7	40.5
General and administrative expenses	[1],[3],[6]	117	67.9	40.5
Equity in earnings (losses) of equity method investees—net	[1],[6]	1.4	3.5	0
Amortization of goodwill and others	[1],[6]	1.8	0.9	0.9
Net business profits (losses) + Net gains (losses) related to ETFs and others	[1],[4],[6]	89.4	3.5	(1)
Fixed assets	[1],[5],[6]	¥ 885.4	¥ 777.3	¥ 794.7
[1]Income and expenses of foreign branches of MHBK and foreign subsidiaries with functional currencies other than Japanese Yen have been translated for purposes of segment reporting using the budgeted foreign currency rates. Prior period comparative amounts for such foreign currency income and expenses have been translated using current period budgeted foreign currency rates.[2]“Gross profits + Net gains (losses) related to ETFs and others” is reported instead of sales reported by general corporations. Gross profits is defined as the sum of net interest income, fiduciary income, net fee and commission income, net trading income and net other operating income. Net gains (losses) related to ETFs and others consist of net gains (losses) on ETFs held by MHBK and MHTB on their non-consolidated basis and net gains (losses) on operating investment securities of MHSC on its consolidated basis. For the fiscal years ended March 31, 2022, 2023 and 2024, net gains (losses) related to ETFs and others amounted to ¥1.9 billion, ¥1.8 billion and ¥(31.0) billion, respectively, of which ¥2.2 billion, ¥(0.2) billion and ¥(37.0) billion are included in “Global Markets Company,” respectively.[3]“General and administrative expenses” excludes non-allocated gains (losses), net.[4]Net business profits (losses) is used in Japan as a measure of the profitability of core banking operations, and is defined as gross profits (as defined above) less general and administrative expenses (excluding non-allocated gains (losses), net) plus equity in earnings (losses) of equity method investees—net less amortization of goodwill and others. Measurement of net business profits (losses) is required for regulatory reporting to the Financial Services Agency of Japan.[5]“Fixed assets” is presented based on Japanese GAAP and corresponds to the total amount of the following U.S. GAAP accounts: Premises and equipment-net; Goodwill; Intangible assets; and right-of-use assets related to operating leases included in Other assets. The above table does not include other asset amounts because “Fixed assets” is the only balance sheet metric that management uses when evaluating and making decisions pertaining to the operating segments. “Others” in “Fixed assets” includes assets of headquarters that have not been allocated to each segment, “Fixed assets” pertaining to consolidated subsidiaries that are not subject to allocation, consolidating adjustments, and others. Certain “Fixed assets” expenses have been allocated to each segment using reasonable allocation criteria.[6]“Others” includes the following items: • profits and expenses pertaining to consolidated subsidiaries that are not subject to allocation; • consolidating adjustments, including elimination of internal transaction between each segment; • equity in earnings (losses) of equity method investees—net that are not subject to allocation; and • profits and losses pertaining to derivative transactions that reflect the counterparty risk of the individual parties and other factors in determining fair market value.

Business Segment Information _2

Business Segment Information (Reportable Segment Information Derived from Internal Management Reporting Systems, on Basis of Japanese GAAP) (Parenthetical) (Detail) - JPY (¥) ¥ in Billions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits and net gains (losses) related to ETFs and others	[1],[2]	¥ 2,672.2	¥ 2,280.2	¥ 2,254.3
Exchange Traded Funds
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits and net gains (losses) related to ETFs and others		(31)	1.8	1.9
Global Markets Company | Exchange Traded Funds
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits and net gains (losses) related to ETFs and others		¥ (37)	¥ (0.2)	¥ 2.2
[1]Income and expenses of foreign branches of MHBK and foreign subsidiaries with functional currencies other than Japanese Yen have been translated for purposes of segment reporting using the budgeted foreign currency rates. Prior period comparative amounts for such foreign currency income and expenses have been translated using current period budgeted foreign currency rates.[2]“Gross profits + Net gains (losses) related to ETFs and others” is reported instead of sales reported by general corporations. Gross profits is defined as the sum of net interest income, fiduciary income, net fee and commission income, net trading income and net other operating income. Net gains (losses) related to ETFs and others consist of net gains (losses) on ETFs held by MHBK and MHTB on their non-consolidated basis and net gains (losses) on operating investment securities of MHSC on its consolidated basis. For the fiscal years ended March 31, 2022, 2023 and 2024, net gains (losses) related to ETFs and others amounted to ¥1.9 billion, ¥1.8 billion and ¥(31.0) billion, respectively, of which ¥2.2 billion, ¥(0.2) billion and ¥(37.0) billion are included in “Global Markets Company,” respectively.

Business Segment Information _3

Business Segment Information (Reconciliation of Total Net Business Profits under Internal Management Reporting Systems to Income Before Income Tax Expense on Consolidated Statements of Income) (Detail) - JPY (¥) ¥ in Billions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net business profits (losses) + Net gains (losses) related to ETFs and others	¥ 1,005.8	¥ 807.1	¥ 853.1
Adjustment to reconcile management reporting to Japanese GAAP:
General and administrative expenses: non-allocated gains (losses), net	28.6	39.7	33.7
Expenses related to portfolio problems (including reversal of (provision for) general reserve for losses on loans)	(114)	(96.7)	(255.9)
Gains on reversal of reserves for possible losses on loans, and others	7.6	7.4	20.8
Net gains (losses) related to stocks—Net gains (losses) related to ETFs and others	54.7	84.6	(45.8)
Net extraordinary gains (losses)	40.9	(10.6)	44
Others	(68.8)	(52.5)	(46.1)
Income before income tax expense under Japanese GAAP	955	779	603.9
Adjustment to reconcile Japanese GAAP to U.S. GAAP:
Derivative financial instruments and hedging activities	50.5	(373.2)	(124)
Investments	571.7	(210.5)	(600.1)
Loans	(8.8)	(30.3)	(18.3)
Allowances for credit losses	25.3	(9.8)	51.5
Premises and equipment	(55.1)	(29.3)	(68.5)
Land revaluation	4.9	5.6	6.4
Business combinations	10.8	8.9	6.9
Pension liabilities	(60.4)	(71.6)	(94.4)
Consolidation of variable interest entities	211.2	0.8	42.3
Foreign currency translation	(83.2)	(5.2)	(51)
Others	0.9	4.8	2.8
Income (loss) before income tax expense (benefit) under U.S. GAAP	¥ 1,623.1	¥ 69.2	¥ (242.5)

Business Segment Information _4

Business Segment Information (Reconciliation of Assets from Segment to Consolidated) (Detail) - JPY (¥) ¥ in Billions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Schedule Of Assets By Segment [Line Items]
Fixed assets	[1],[2]	¥ 1,864.6	¥ 1,678.5	¥ 1,697.2
U.S. GAAP adjustments	[3]	582.2	662.6	717.6
Premises and equipment-net, Goodwill, Intangible assets, and right-of-use assets related to operating leases included in Other assets		¥ 2,446.9	¥ 2,341.2	¥ 2,414.9
[1]Income and expenses of foreign branches of MHBK and foreign subsidiaries with functional currencies other than Japanese Yen have been translated for purposes of segment reporting using the budgeted foreign currency rates. Prior period comparative amounts for such foreign currency income and expenses have been translated using current period budgeted foreign currency rates.[2]“Fixed assets” is presented based on Japanese GAAP and corresponds to the total amount of the following U.S. GAAP accounts: Premises and equipment-net; Goodwill; Intangible assets; and right-of-use assets related to operating leases included in Other assets. The above table does not include other asset amounts because “Fixed assets” is the only balance sheet metric that management uses when evaluating and making decisions pertaining to the operating segments. “Others” in “Fixed assets” includes assets of headquarters that have not been allocated to each segment, “Fixed assets” pertaining to consolidated subsidiaries that are not subject to allocation, consolidating adjustments, and others. Certain “Fixed assets” expenses have been allocated to each segment using reasonable allocation criteria.[3]The U.S. GAAP adjustments are primarily comprised of GAAP differences mainly from right-of-use assets related to operating leases not recognized under Japanese GAAP; internally developed software, which was impaired under Japanese GAAP; land, which was revalued under Japanese GAAP; and the consolidation of certain variable interest entities, which are not consolidated under Japanese GAAP.

Foreign Activities (Consolidate

Foreign Activities (Consolidated Income Statement and Total Assets Information by Major Geographic Area) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Segment Reporting Information [Line Items]
Total revenue	[1]	¥ 8,510,700	¥ 4,276,900	¥ 2,113,700
Total expenses	[2]	6,887,600	4,207,700	2,356,200
Income (loss) before income tax expense (benefit)		1,623,100	69,200	(242,500)
Net income (loss)	[3]	1,197,992	34,028	(101,471)
Total assets		272,173,152	248,780,722	231,550,700
Japan
Segment Reporting Information [Line Items]
Total revenue	[1]	2,827,100	1,104,700	991,100
Total expenses	[2]	2,171,800	1,784,100	1,713,800
Income (loss) before income tax expense (benefit)		655,300	(679,400)	(722,700)
Net income (loss)		449,000	(554,700)	(509,000)
Total assets		170,063,800	161,348,700	155,111,200
United States of America
Segment Reporting Information [Line Items]
Total revenue	[1]	3,584,400	1,841,500	562,900
Total expenses	[2]	2,978,700	1,455,400	265,000
Income (loss) before income tax expense (benefit)		605,600	386,100	297,900
Net income (loss)		491,100	297,200	275,200
Total assets		57,036,000	45,516,400	36,765,700
Others
Segment Reporting Information [Line Items]
Total revenue	[1]	198,500	93,100	41,700
Total expenses	[2]	191,600	84,700	19,000
Income (loss) before income tax expense (benefit)		6,800	8,400	22,700
Net income (loss)		(1,600)	1,800	18,300
Total assets		4,483,000	3,579,600	3,667,900
Europe
Segment Reporting Information [Line Items]
Total revenue	[1]	803,700	445,900	184,800
Total expenses	[2]	817,100	413,000	189,200
Income (loss) before income tax expense (benefit)		(13,300)	32,900	(4,400)
Net income (loss)		(50,000)	19,900	(16,300)
Total assets		19,142,100	16,634,700	15,795,900
Asia/Oceania excluding Japan, and others
Segment Reporting Information [Line Items]
Total revenue	[1]	1,097,100	791,700	333,200
Total expenses	[2]	728,400	470,500	169,200
Income (loss) before income tax expense (benefit)		368,600	321,200	164,000
Net income (loss)		309,500	269,800	130,300
Total assets		¥ 21,448,200	¥ 21,701,300	¥ 20,210,000
[1]Total revenue is comprised of Interest and dividend income and Noninterest income.[2]Total expenses are comprised of Interest expense, Provision (credit) for credit losses and Noninterest expenses.[3]The amounts that have been reclassified out of Accumulated other comprehensive income (loss), net of tax into net income are presented in Note 16 “Accumulated other comprehensive income (loss), net of tax.”

Mizuho Financial Group, Inc.,_3

Mizuho Financial Group, Inc., Parent Company (Condensed Balance Sheets) (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Assets:
Cash and due from banking subsidiaries	¥ 2,046,324	¥ 2,241,929
Interest-bearing deposits in banking subsidiaries	72,066,719	65,750,366
Other assets	8,280,151	9,700,960
Total assets	272,173,152	248,780,722	¥ 231,550,700
Liabilities and shareholders' equity:
Long-term debt	16,277,331	14,893,023
Other liabilities	6,268,999	6,316,695
Shareholders' equity	9,929,071	8,915,491
Total liabilities and equity	272,173,152	248,780,722
Parent Company
Assets:
Cash and due from banking subsidiaries	23,394	47,425
Interest-bearing deposits in banking subsidiaries	431	450
Other assets	629,277	545,744
Total assets	20,512,853	18,878,433
Liabilities and shareholders' equity:
Short-term borrowings from a banking subsidiary	631,000	810,000
Long-term debt	9,546,009	8,741,729
Other liabilities	406,773	411,213
Shareholders' equity	9,929,071	8,915,491
Total liabilities and equity	20,512,853	18,878,433
Parent Company | Banking Subsidiaries
Assets:
Investments in subsidiaries and affiliated companies	8,542,884	7,996,767
Parent Company | Banking Subsidiaries | Affiliated Entity
Assets:
Long-term loans receivable from subsidiaries	9,567,224	8,768,725
Parent Company | Non Banking Subsidiaries And Affiliated Companies
Assets:
Investments in subsidiaries and affiliated companies	1,305,643	1,075,322
Parent Company | Non Banking Subsidiaries And Affiliated Companies | Affiliated Entity
Assets:
Long-term loans receivable from subsidiaries	¥ 444,000	¥ 444,000

Mizuho Financial Group, Inc.,_4

Mizuho Financial Group, Inc., Parent Company (Condensed Statements of Income) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Income:
Total	[1]	¥ 8,510,700	¥ 4,276,900	¥ 2,113,700
Expenses:
Interest expense		4,562,076	2,180,064	374,132
Equity in undistributed net income (loss) of subsidiaries and affiliated companies—net	[2]	19,791	(26,999)	34,587
Income tax expense (benefit)		425,120	35,142	(141,017)
Net income (loss) attributable to MHFG shareholders		912,473	(14,009)	(104,722)
Parent Company
Income:
Management fees from subsidiaries		51,770	43,900	40,462
Gains on sales of investments in subsidiaries		0	0	53,005
Other income		4,444	37,319	11,319
Total		847,800	530,311	517,823
Expenses:
Operating expenses		60,037	52,887	43,192
Interest expense		230,780	175,723	130,453
Losses on sales of investments in a subsidiary		0	0	26,606
Other expense		11,286	2,768	5,946
Total		302,103	231,378	206,197
Equity in undistributed net income (loss) of subsidiaries and affiliated companies—net		365,266	(307,879)	(505,891)
Income (loss) before income tax expense (benefit)		910,964	(8,946)	(194,265)
Income tax expense (benefit)		(1,509)	5,063	(89,543)
Net income (loss) attributable to MHFG shareholders		912,473	(14,009)	(104,722)
Parent Company | Related Party
Income:
Interest income on loans and discounts		232,272	177,137	133,215
Parent Company | Banking Subsidiary
Income:
Banking subsidiaries		547,487	209,257	197,717
Parent Company | Non Banking Subsidiaries And Affiliated Companies
Income:
Banking subsidiaries		¥ 11,826	¥ 62,698	¥ 82,105
[1]Total revenue is comprised of Interest and dividend income and Noninterest income.[2]These amounts are revenues from contracts that do not meet the scope of ASC 606.

Mizuho Financial Group, Inc.,_5

Mizuho Financial Group, Inc., parent company (Condensed statements of cash flows) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities:
Net income (loss)	¥ 912,473	¥ (14,009)	¥ (104,722)
Net cash provided by operating activities	(3,460,502)	1,006,913	5,498,087
Cash flows from investing activities:
Purchases of investments in a subsidiaries	(55,469)	(48,887)	(93,005)
Net cash provided by (used in) investing activities	(3,679,457)	6,190,488	(5,016,128)
Cash flows from financing activities:
Net change in short-term borrowings	14,167	(4,338,379)	(1,711,421)
Proceeds from issuance of long-term debt	3,061,735	4,701,954	3,004,293
Repayment of long-term debt	(2,956,548)	(2,985,756)	(2,715,054)
Purchases of treasury stock	(3,384)	(2,314)	(1,927)
Net cash provided by financing activities	11,457,601	7,762,851	1,991,438
Net increase in cash and cash equivalents	6,120,748	15,818,006	3,440,193
Cash and cash equivalents at beginning of fiscal year	67,992,295	52,174,289	48,734,096
Cash and cash equivalents at end of fiscal year	74,113,043	67,992,295	52,174,289
Parent Company
Cash flows from operating activities:
Net income (loss)	912,473	(14,009)	(104,722)
Adjustments and other	(421,191)	394,191	351,484
Net cash provided by operating activities	491,282	380,182	246,762
Cash flows from investing activities:
Net change in loans	(130,719)	(511,934)	(72,313)
Purchases of investments in a subsidiaries	(91,200)	(179,210)	0
Proceeds from sales of investments in subsidiaries	0	721	452,500
Net change in other investing activities	(9,983)	(5,673)	208
Net cash provided by (used in) investing activities	(231,902)	(696,095)	380,395
Cash flows from financing activities:
Net change in short-term borrowings	(179,000)	55,000	(95,000)
Proceeds from issuance of long-term debt	1,363,655	1,497,032	930,033
Repayment of long-term debt	(1,232,936)	(1,030,099)	(1,256,720)
Purchases of treasury stock	(2,478)	(1,575)	(1,927)
Dividends paid	(234,787)	(209,457)	(196,783)
Net change in other financing activities	2,116	1,117	44
Net cash provided by financing activities	(283,431)	312,018	(620,353)
Net increase in cash and cash equivalents	(24,050)	(3,895)	6,804
Cash and cash equivalents at beginning of fiscal year	47,875	51,770	44,966
Cash and cash equivalents at end of fiscal year	¥ 23,825	¥ 47,875	¥ 51,770