Mizuho Financial (MFG) 6-K 28 Dec 22 2022 Q2 Current report (foreign) Financial data

Cover Page

Cover Page	6 Months Ended
	Sep. 30, 2022
Document Information [Line Items]
Document Type	6-K
Amendment Flag	false
Document Period End Date	Sep. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Entity Registrant Name	Mizuho Financial Group, Inc.
Entity Central Index Key	0001335730
Current Fiscal Year End Date	--03-31

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - JPY (¥) ¥ in Millions	Sep. 30, 2022	Mar. 31, 2022
Assets:
Cash and due from banks	¥ 2,524,631	¥ 2,290,377
Interest-bearing deposits in other banks	53,048,350	49,883,912
Call loans and funds sold	1,454,185	1,102,296
Receivables under resale agreements	14,872,079	12,751,085
Receivables under securities borrowing transactions	2,355,125	2,338,796
Trading account assets	35,330,944	24,652,067
Investments (Note 3):
Available-for-sale securities (including assets pledged that secured parties are permitted to sell or repledge of ¥1,120,839 million at March 31, 2022 and ¥1,389,462 million at September 30, 2022), net of allowance	23,743,660	31,673,890
Held-to-maturity securities (including assets pledged that secured parties are permitted to sell or repledge of ¥1,019,391 million at March 31, 2022 and ¥1,223,062 million at September 30, 2022)	2,072,468	1,519,055
Equity securities	3,439,981	3,572,908
Other investments	626,148	582,388
Loans (Notes 4 and 5)	98,334,291	90,290,583
Allowance for credit losses on loans	(710,746)	(809,817)
Loans, net of allowance	97,623,545	89,480,766
Premises and equipment—net	1,680,618	1,704,067
Due from customers on acceptances	376,369	271,877
Accrued income	422,673	322,025
Goodwill	96,141	92,695
Intangible assets	48,926	47,939
Deferred tax assets	516,091	277,319
Other assets (Note 6)	10,519,434	8,987,242
Total assets	250,751,368	231,550,704
Liabilities and equity:
Noninterest-bearing deposits	27,849,570	32,844,872
Interest-bearing deposits	94,941,299	91,425,213
Noninterest-bearing deposits	2,569,090	2,500,823
Interest-bearing deposits	39,592,020	30,407,376
Due to trust accounts	350,124	390,247
Call money and funds purchased	1,572,353	1,278,051
Payables under repurchase agreements (Note 19)	23,767,150	20,069,566
Payables under securities lending transactions (Note 19)	1,490,659	1,360,743
Other short-term borrowings	3,593,275	7,566,771
Trading account liabilities	24,229,013	14,859,383
Bank acceptances outstanding	376,369	271,877
Income taxes payable	78,575	62,697
Deferred tax liabilities	20,752	29,033
Accrued expenses	316,980	203,383
Long-term debt	13,546,803	12,578,216
Other liabilities (Note 6)	7,020,295	6,260,222
Total	241,314,327	222,108,473
Commitments and contingencies (Note 14)
MHFG shareholders' equity:
Common stock (Note 7)-no par value, authorized 4,800,000,000 shares at March 31, 2022 and September 30, 2022, and issued 2,539,249,894 shares at March 31, 2022 and September 30, 2022	5,832,367	5,816,834
Retained earnings	2,185,055	2,665,608
Accumulated other comprehensive income(loss), net of tax (Note 8)	698,835	440,112
Less: Treasury stock, at cost-Common stock 4,659,024 shares at March 31, 2022, and 4,930,963 shares at September 30, 2022	(8,552)	(8,342)
Total MHFG shareholders' equity	8,707,705	8,914,212
Noncontrolling interests	729,336	528,019
Total equity	9,437,041	9,442,231
Total liabilities and equity	250,751,368	231,550,704
Consolidated VIEs
Assets:
Cash and due from banks	1,664	2,243
Interest-bearing deposits in other banks	175,768	71,573
Call loans and funds sold	223,503	162,578
Trading account assets	2,540,402	2,222,902
Investments (Note 3):
Investments	253,654	238,624
Loans, net of allowance	8,503,789	8,347,880
Other assets (Note 6)	475,885	529,178
Total assets	12,174,665	11,574,978
Liabilities and equity:
Payables under securities lending transactions (Note 19)	118,768	51,752
Other short-term borrowings	129,240	53,668
Trading account liabilities	31,621	51,019
Long-term debt	1,217,297	1,024,067
Other liabilities (Note 6)	1,059,776	1,041,938
Total	¥ 2,556,702	¥ 2,222,444

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - JPY (¥) ¥ in Millions	Sep. 30, 2022	Mar. 31, 2022
Trading account assets, assets pledged that secured parties are permitted to sell or repledge	¥ 7,233,590	¥ 4,639,282
Available-for-sale securities, assets pledged that secured parties are permitted to sell or repledge	1,389,462	1,120,839
Held-to-maturity securities, assets pledged that secured parties are permitted to sell or repledge	1,223,062	1,019,391
Long-term debt, liabilities accounted for at fair value	¥ 2,736,380	¥ 2,756,062
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	4,930,963	4,659,024

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - JPY (¥) ¥ in Millions		6 Months Ended
		Sep. 30, 2022	Sep. 30, 2021
Interest and dividend income:
Loans, including fees		¥ 748,122	¥ 470,961
Investments:
Interest		42,293	26,458
Dividends		37,132	37,724
Trading account assets		189,435	109,477
Call loans and funds sold		2,263	779
Receivables under resale agreements and securities borrowing transactions		87,129	12,861
Deposits in other banks		134,632	25,841
Total interest and dividend income		1,241,006	684,101
Interest expense:
Deposits		265,849	34,732
Trading account liabilities		55,297	28,488
Call money and funds purchased		5,298	492
Payables under repurchase agreements and securities lending transactions		177,958	13,678
Other short-term borrowings		11,088	1,497
Long-term debt		110,453	81,114
Total interest expense		625,943	160,001
Net interest income		615,063	524,100
Provision (credit) for credit losses (Notes 3 and 5)		37,646	46,053
Net interest income after provision (credit) for credit losses		577,417	478,047
Noninterest income (Note 16):
Fee and commission income		448,744	474,916
Foreign exchange gains (losses)-net		128,897	21,708
Trading account gains (losses)-net		(851,080)	83,255
Investment gains (losses)-net:
Debt securities		8,057	(317)
Equity securities		(113,461)	135,070
Equity in earnings (losses) of equity method investees-net	[1]	(5,003)	16,541
Gains on disposal of premises and equipment	[1]	1,811	1,988
Other noninterest income	[2],[3]	168,254	29,234
Total noninterest income (loss)		(213,781)	762,395
Noninterest expenses:
Salaries and employee benefits		340,108	327,085
General and administrative expenses		339,648	294,259
Occupancy expenses		82,980	90,509
Fee and commission expenses		102,903	107,658
Provision (credit) for credit losses on off-balance-sheet instruments		5,590	(4,821)
Other noninterest expenses		55,019	42,552
Total noninterest expenses		926,248	857,242
Income (loss) before income tax expense (benefit)		(562,612)	383,200
Income tax expense (benefit) (Note 11)		(171,905)	39,622
Net income (loss)	[4]	(390,707)	343,578
Less: Net income (loss) attributable to noncontrolling interests		(11,830)	30,921
Net income (loss) attributable to MHFG shareholders		¥ (378,877)	¥ 312,657
Earnings per common share (Note 10):
Basic net income (loss) per common share		¥ (149.38)	¥ 123.24
Diluted net income (loss) per common share	[5]	(149.38)	123.24
Dividends per common share		¥ 42.5	¥ 40
[1]These amounts are revenues from contracts that do not meet the scope of 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 include the net unrealized gains resulting from changes in fair values of structured notes that contain embedded derivatives. See Note 17 “Fair value” for further details.[4]The amounts that have been reclassified out of Accumulated other comprehensive income (loss), net of tax into net income are presented in Note 8 “Accumulated other comprehensive income (loss), net of tax.”[5]For the six months ended September 30, 2022, 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 six months ended September 30, 2022, 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		6 Months Ended
		Sep. 30, 2022	Sep. 30, 2021
Net income (loss)	[1]	¥ (390,707)	¥ 343,578
Other comprehensive income (loss), net of tax		260,349	38,196
Total comprehensive income (loss)		(130,358)	381,774
Less: Total comprehensive income (loss) attributable to noncontrolling interests		(10,205)	31,446
Total comprehensive income (loss) attributable to MHFG shareholders		¥ (120,153)	¥ 350,328
[1]The amounts that have been reclassified out of Accumulated other comprehensive income (loss), net of tax into net income are presented in Note 8 “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 period at Mar. 31, 2021		¥ 5,826,863	¥ 2,967,385	¥ 318,114		¥ (7,124)		¥ 582,919
Purchases of treasury stock						(2,647)
Performance-based stock compensation program		(538)
Change in ownership interests in consolidated subsidiaries		(9,960)
Disposal of treasury stock						1,607
Net income (loss) attributable to MHFG shareholders	¥ 312,657		312,657
Change during period	38,196			37,671
Dividends declared			(95,201)
Other			(52)
Transactions between the MHFG Group and the noncontrolling interest shareholders								89,808
Dividends paid to noncontrolling interests								(10,807)
Net income (loss) attributable to noncontrolling interests	30,921							30,921
Other								525
Balance at end of period at Sep. 30, 2021	10,042,141	5,816,365	3,184,789	355,785		(8,164)	¥ 9,348,775	693,366
Balance at beginning of period at Mar. 31, 2022	9,442,231	5,816,834	2,665,608	440,112		(8,342)		528,019
Purchases of treasury stock						(1,941)
Performance-based stock compensation program		(740)
Change in ownership interests in consolidated subsidiaries		16,273
Disposal of treasury stock						1,731
Net income (loss) attributable to MHFG shareholders	(378,877)		(378,877)
Change during period	260,349			258,723
Dividends declared			(101,543)
Other			(133)
Transactions between the MHFG Group and the noncontrolling interest shareholders								226,180
Dividends paid to noncontrolling interests								(14,658)
Net income (loss) attributable to noncontrolling interests	(11,830)							(11,830)
Other								1,625
Balance at end of period at Sep. 30, 2022	¥ 9,437,041	¥ 5,832,367	¥ 2,185,055	¥ 698,835		¥ (8,552)	¥ 8,707,705	¥ 729,336
[1]The amounts that have been reclassified out of Accumulated other comprehensive income (loss), net of tax into net income are presented in Note 8 “Accumulated other comprehensive income (loss), net of tax.”

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - JPY (¥) ¥ in Millions		6 Months Ended
		Sep. 30, 2022	Sep. 30, 2021
Cash flows from operating activities:
Net income (loss)	[1]	¥ (390,707)	¥ 343,578
Less: Net income (loss) attributable to noncontrolling interests		(11,830)	30,921
Net income (loss) attributable to MHFG shareholders		(378,877)	312,657
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization		126,328	115,756
Provision (credit) for credit losses		37,646	46,053
Investment losses (gains)-net		105,404	(134,753)
Equity in losses (earnings) of equity method investees-net	[2]	5,003	(16,541)
Foreign exchange losses (gains)-net		739,266	35,446
Deferred income tax expense (benefit)		(239,149)	(28,200)
Net change in trading account assets		(9,096,063)	(271,232)
Net change in trading account liabilities		9,008,728	(1,734,070)
Net change in loans held for sale		(122,683)	(16,915)
Net change in accrued income		(80,069)	13,325
Net change in accrued expenses		108,023	(32,858)
Other-net		(181,041)	480,671
Net cash provided by (used in) operating activities		32,516	(1,230,661)
Cash flows from investing activities:
Proceeds from sales of Available-for-sale securities		22,862,094	20,872,060
Proceeds from sales of Equity securities	[3]	579,215	992,927
Proceeds from maturities of Available-for-sale securities		21,944,842	26,506,201
Proceeds from maturities of Held-to-maturity securities		79,580	79,767
Purchases of Available-for-sale securities		(38,002,539)	(45,046,101)
Purchases of Held-to-maturity securities		(453,020)	(542,026)
Purchases of Equity securities	[3]	(582,312)	(1,311,347)
Proceeds from sales of loans		255,831	1,038,124
Net change in loans		(4,681,239)	496,474
Net change in call loans and funds sold, and receivables under resale agreements and securities borrowing transactions		(1,141,636)	(4,518,794)
Proceeds from sales of premises and equipment		2,362	2,806
Purchases of premises and equipment		(84,327)	(52,234)
Proceeds from sales of investments in subsidiaries (affecting the scope of consolidation)		2,872	5,391
Purchases of investments in subsidiaries (affecting the scope of consolidation)		(49,185)	(50,723)
Net cash provided by (used in) investing activities		732,538	(1,527,475)
Cash flows from financing activities:
Net change in deposits		4,103,867	(2,187,631)
Net change in call money and funds purchased, and payables under repurchase agreements and securities lending transactions		1,313,784	3,776,203
Net change in due to trust accounts		(40,123)	28,047
Net change in other short-term borrowings		(4,277,836)	(71,262)
Proceeds from issuance of long-term debt		1,198,626	1,442,089
Repayment of long-term debt		(1,245,843)	(1,179,807)
Proceeds from noncontrolling interests		418	67,785
Payments to noncontrolling interests		(50,642)	(1,845)
Proceeds from sales of treasury stock		1,009	869
Purchases of treasury stock		(1,270)	(1,825)
Dividends paid		(101,546)	(95,198)
Dividends paid to noncontrolling interests		(14,658)	(10,807)
Net cash provided by financing activities		885,786	1,766,618
Effect of exchange rate changes on cash and cash equivalents		1,747,852	83,750
Net increase (decrease) in cash and cash equivalents	[4]	3,398,692	(907,768)
Cash and cash equivalents at beginning of period	[4]	52,174,289	48,734,096
Cash and cash equivalents at end of period	[4]	55,572,981	47,826,328
Noncash investing activities:
Transfer of loans into loans held-for-sale		¥ 15,744	¥ 15,357
[1]The amounts that have been reclassified out of Accumulated other comprehensive income (loss), net of tax into net income are presented in Note 8 “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.[4]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.

Basis of presentation

Basis of presentation	6 Months Ended
	Sep. 30, 2022
Basis of presentation	1. 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 20 “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 interim financial reporting period ends on September 30. Certain of MHFG’s subsidiaries have different interim financial reporting periods than September 30. For those subsidiaries with interim financial reporting periods within three months of MHFG’s interim financial reporting period, the effect of intervening events that materially affect the financial position or results of operations through the date of each of the periods presented in the MHFG’s consolidated financial statements have 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. The unaudited interim consolidated financial statements should be read in conjunction with the audited financial statements and related notes included in the MHFG Group’s most recent annual report on Form 20-F Certain financial information that is normally included in annual financial statements prepared in accordance with U.S. GAAP, but is not required for interim reporting purposes, has been condensed or omitted. The financial statements reflect all normal and recurring adjustments that are, in the opinion of management, necessary for a fair presentation of the results for the interim periods. 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 deferred tax assets, valuation of derivative financial instruments, valuation of investments, valuation of certain long-term debt where the fair value option has been elected, valuation of pension and other employee benefits, and impairment of long-lived assets. During times of pandemics, such as COVID-19, 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 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 in each reporting period. 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 scenario does not reflect a sudden change in economic conditions adequately, adjustments may be made to the scenario. 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 segment, the MHFG Group considers key economic factors such as gross domestic products for Japan and each relevant foreign location, where the portfolio is significant, and the interest rates in Japan when estimating the credit loss. 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 loan and others. For the retail portfolio segment, the Japanese unemployment rate is applied as a key factor. As it pertains to troubled debt restructuring (“TDR”) loans 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 TDRs, discounted at the loan’s initial 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 are affecting 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 COVID-19 In terms of the Russia-Ukraine situation, considering the country risk arising from the sanctions against Russia and the downgrading of their credit rating, as well as the risk of deterioration in the global economy due to inflation caused by soaring energy prices and the acceleration of supply chain disruptions caused by the withdrawal of operations from Russia, the MHFG Group incorporated an estimate 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 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 available-for-sale

Issued accounting pronouncement

Issued accounting pronouncements	6 Months Ended
	Sep. 30, 2022
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.2020-04 No.2021-01 Accounting pronouncements issued but not yet effective as of September 30 , 2022 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

Investments

Investments	6 Months Ended
	Sep. 30, 2022
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) March 31, 2022 Available-for-sale Debt securities: Japanese government bonds 25,191,315 5,794 38,379 25,158,730 Japanese local government bonds 421,557 254 2,165 419,646 U.S. Treasury bonds and federal agency securities 381,653 — 8,444 373,209 Other foreign government bonds 1,338,295 220 2,578 1,335,937 Agency mortgage-backed securities (1) 452,830 1,695 3,985 450,540 Residential mortgage-backed securities 58,246 194 312 58,128 Commercial mortgage-backed securities 848,568 5,437 214 853,791 Japanese corporate bonds and other debt securities 2,222,670 14,212 1,705 2,235,177 Foreign corporate bonds and other debt securities (2) 787,263 2,490 1,021 788,732 Total 31,702,397 30,296 58,803 31,673,890 Held-to-maturity Debt securities: Japanese government bonds 479,980 5,101 — 485,081 Agency mortgage-backed securities (3) 1,039,075 24 58,604 980,495 Total 1,519,055 5,125 58,604 1,465,576 September 30, 2022 Available-for-sale Debt securities: Japanese government bonds 17,134,700 6,614 38,011 17,103,303 Japanese local government bonds 500,473 149 3,959 496,663 U .S. Treasury bonds and federal agency securities 448,530 — 13,737 434,793 Other foreign government bonds 1,284,950 97 4,804 1,280,243 Agency mortgage-backed securities (1) 500,825 1,112 7,579 494,358 Residential mortgage-backed securities 52,866 97 863 52,100 Commercial mortgage-backed securities 864,060 4,838 321 868,577 Japanese corporate bonds and other debt securities 2,115,489 10,422 4,095 2,121,816 Foreign corporate bonds and other debt securities (2) 891,279 2,193 1,665 891,807 Total 23,793,172 25,522 75,034 23,743,660 Held-to-maturity Debt securities: Japanese government bonds 839,581 3,973 667 842,887 Agency mortgage-backed securities (3) 1,232,887 — 183,109 1,049,778 Total 2,072,468 3,973 183,776 1,892,665 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 ¥450,507 million and ¥33 million, respectively, at March 31, 2022, and ¥494,324 (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 ¥247,762 million at March 31, 2022, and ¥226,762 million at September 30, 2022. (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 ere , and ¥nil at September 30, 2022. (5) Accrued interest receivables are excluded from amortized cost, of which the amount were ¥4,702 million at March 31, 2022, and ¥5,274 million at September 30, 2022 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 13,784,027 1,527,715 1,695,453 127,505 17,134,700 Japanese local government bonds 31,462 254,156 207,348 7,507 500,473 U.S. Treasury bonds and federal agency securities 289,397 159,133 — — 448,530 Other foreign government bonds 1,081,620 200,767 1,283 1,280 1,284,950 Agency mortgage-backed securities — — 1,235 499,590 500,825 Residential mortgage-backed securities — — — 52,866 52,866 Commercial mortgage-backed securities 5,000 518,740 340,320 — 864,060 Japanese corporate bonds and other debt securities 275,168 1,263,577 253,180 323,564 2,115,489 Foreign corporate bonds and other debt securities 485,021 298,537 88,524 19,197 891,279 Total 15,951,695 4,222,625 2,587,343 1,031,509 23,793,172 Held-to-maturity Debt securities: Japanese government bonds 319,987 249,965 269,629 — 839,581 Agency mortgage-backed securities — — — 1,232,887 1,232,887 Total 319,987 249,965 269,629 1,232,887 2,072,468 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 13,785,916 1,523,649 1,674,710 119,028 17,103,303 Japanese local government bonds 31,490 253,676 204,283 7,214 496,663 U.S. Treasury bonds and federal agency securities 282,356 152,437 — — 434,793 Other foreign government bonds 1,079,499 198,182 1,282 1,280 1,280,243 Agency mortgage-backed securities — — 1,229 493,129 494,358 Residential mortgage-backed securities — — — 52,100 52,100 Commercial mortgage-backed securities 4,997 521,126 342,454 — 868,577 Japanese corporate bonds and other debt securities 275,173 1,262,115 252,101 332,427 2,121,816 Foreign corporate bonds and other debt securities 484,357 298,704 88,589 20,157 891,807 Total 15,943,788 4,209,889 2,564,648 1,025,335 23,743,660 Held-to-maturity Debt securities: Japanese government bonds 321,991 251,598 269,298 — 842,887 Agency mortgage-backed securities — — — 1,049,778 1,049,778 Total 321,991 251,598 269,298 1,049,778 1,892,665 Credit losses Allowance for credit losses on available-for-sale billion as of September 30, 2021 due mainly to a decrease of credit losses for certain Japanese corporate bonds and other debt securities, not due to the reduction or sale of securities during the period. The MHFG Group did not available-for-sale billion from March 31, 2022. The decrease was due to a sale of certain Japanese corporate bonds and other debt securities during the period. The Group did not 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) March 31, 2022 Available-for-sale Debt securities: Japanese government bonds 19,407,878 11,377 1,565,950 27,002 20,973,828 38,379 Japanese local government bonds 229,562 1,277 136,733 888 366,295 2,165 U.S. Treasury bonds and federal agency securities 321,073 7,209 41,555 1,235 362,628 8,444 Other foreign government bonds 729,134 2,178 71,647 400 800,781 2,578 Agency mortgage-backed securities (Note) 183,150 2,326 78,717 1,659 261,867 3,985 Residential mortgage-backed securities 9,221 11 17,193 301 26,414 312 Commercial mortgage-backed securities 58,815 185 13,939 29 72,754 214 Japanese corporate bonds and other debt securities 605,067 1,516 53,020 189 658,087 1,705 Foreign corporate bonds and other debt securities 302,569 692 53,338 329 355,907 1,021 Total 21,846,469 26,771 2,032,092 32,032 23,878,561 58,803 September 30, 2022 Available-for-sale Debt securities: Japanese government bonds 2,725,251 5,019 1,640,200 32,992 4,365,451 38,011 Japanese local government bonds 283,423 2,123 173,980 1,836 457,403 3,959 U.S. Treasury bonds and federal agency securities 373,689 11,682 48,585 2,055 422,274 13,737 Other foreign government bonds 813,981 3,014 208,218 1,790 1,022,199 4,804 Agency mortgage-backed securities (Note) 222,199 3,457 128,252 4,122 350,451 7,579 Residential mortgage-backed securities 25,540 404 15,278 459 40,818 863 Commercial mortgage-backed securities 65,732 168 45,097 153 110,829 321 Japanese corporate bonds and other debt securities 1,470,008 3,741 365,809 354 1,835,817 4,095 Foreign corporate bonds and other debt securities 346,861 1,102 55,116 563 401,977 1,665 Total 6,326,684 30,710 2,680,535 44,324 9,007,219 75,034 Note: Agency mortgage-backed securities presented in this line consist of Japanese agency mortgage-backed securities, of which the fair values were ¥261,867 million at March 31, 2022, and ¥350,451 million at September 30, 2022. All Japanese agency mortgage-backed securities are issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise. At September 30, 2022, the MHFG Group did not intend to sell the debt securities in an unrealized loss position and it was not more likely than not that the Group would be required to sell them before the recovery of their amortized cost bases. For Japanese government bonds, U.S. Treasury bonds and federal agency securities and Agency mortgage-backed securities, their entire amortized cost bases were expected to be recovered since the unrealized losses had not resulted from credit deterioration, but primarily from changes in interest rates. For the debt securities other than those described above, except for the securities for which credit losses have been recognized in income, the Group determined that their entire amortized cost bases were expected to be recovered, after considering various factors such as the extent to which their fair values were below their amortized cost bases, the external and/or internal ratings and the present values of cash flows expected to be collected. Based on the aforementioned evaluation, except for the securities for which credit losses have been recognized in income, the Group determined that the debt securities in an unrealized loss position were not considered credit losses. Realized gains and losses The following table shows the realized gains and losses on sales of available-for-sale See “Consolidated Statements of Cash Flows (Unaudited)” for the proceeds from sales of investments. Six months ended September 30, 2021 2022 (in millions of yen) Gross realized gains 4,687 15,905 Gross realized losses (3,925 ) (9,151 ) Net realized gains (losses) on sales of available-for-sale 762 6,754 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 six months ended September 30, 2021 and 2022: Six months ended September 30, 2021 2022 (in millions of yen) Net gains (losses) recognized during the period on equity securities 135,070 (113,461 ) Less: Net gains (losses) recognized during the period on equity securities sold during the period 29,552 7,246 Unrealized gains (losses) recognized during the reporting period on equity securities still held at the reporting period 105,518 (120,707 ) 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 and September 30, 2022: March 31, 2022 September 30, 2022 (in millions of yen) Carrying amounts at the end of the period 207,407 193,297 Downward adjustments and impairments 6,519 6,887 Upward adjustments 11,623 12,225 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. Six months ended September 30, 2021 2022 (in millions of yen) Downward adjustments and impairments 1,704 799 Upward adjustments 14,950 669 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, 2022 and September 30, 2022: March 31, 2022 September 30, 2022 (in millions of yen) Equity method investments 519,552 556,778 Investments held by consolidated investment companies and other 62,836 69,370 Total 582,388 626,148 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 ¥255,336 million and ¥268,393 million, at March 31, 2022 and September 30, 2022, respectively. The aggregate market values of these marketable equity securities were ¥456,195 million and ¥452,342 million, respective ly. The majority of the aggregate market values of these marketable equity securities include Orient Corporation, the Chiba Kogyo Bank, Ltd., 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 %, %, % and %, respectively, as of September 30, 2022. In addition, equity method investments include non-marketable equity securities such as Matthews International Capital Management, LLC and Custody Bank of Japan, Ltd. of which the MHFG Group’s proportionate share of the total outstanding common stock were % and %, respectively, as of September 30, 2022. 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 MHFG Group maintains this specialized industry accounting for investments held by consolidated investment companies, which consist of marketable and non-marketable

Loans

Loans	6 Months Ended
	Sep. 30, 2022
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 was ¥80,959 million and ¥145,845 million at March 31, 2022 and September 30, 2022, respectively and 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 debt in TDR 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, 2022 and September 30, 2022: March 31, 2022 Term loans by origination year Revolving Loans Total 2021 2020 2019 2018 2017 Prior to 2017 (in millions of yen) Domestic: Corporate: Large companies: Normal obligors 12,236,438 6,640,211 5,049,408 4,535,083 1,678,591 3,378,926 7,155,041 40,673,698 Watch obligors excluding special attention obligors 145,167 69,404 71,937 66,122 40,205 50,499 127,319 570,653 Nonaccrual loans 60,525 100,975 201,375 44,919 135,777 77,602 178,416 799,589 Small and medium-sized Normal obligors 540,315 396,611 376,056 283,061 170,952 494,420 547,726 2,809,141 Watch obligors excluding special attention obligors 44,488 31,196 29,597 31,919 12,231 32,511 25,277 207,219 Nonaccrual loans 17,866 20,110 14,434 10,817 7,081 38,171 32,081 140,560 Retail: Housing Loan: Normal obligors 798,354 544,246 518,662 526,828 543,893 4,752,430 — 7,684,413 Watch obligors excluding special attention obligors 1,512 1,485 1,510 1,939 1,226 40,243 — 47,915 Nonaccrual loans 12,510 3,132 802 1,180 970 30,598 — 49,192 Others: Normal obligors 195,545 277,015 111,702 90,880 60,919 315,375 497,173 1,548,609 Watch obligors excluding special attention obligors 23,586 34,974 10,177 7,995 4,122 6,388 9,491 96,733 Nonaccrual loans 6,932 7,862 3,157 4,253 4,076 22,951 12,602 61,833 Sovereign: Normal obligors 938,534 105,966 89,385 108,664 54,580 351,876 1,864 1,650,869 Watch obligors excluding special attention obligors 3,933 4,205 859 366 113 — — 9,476 Nonaccrual loans — — — — — — — — Banks and other financial institutions: Normal obligors 45,825 23,757 131,932 211,445 3 143,717 125,078 681,757 Watch obligors excluding special attention obligors — — — — — — — — Nonaccrual loans — — — — — — — — Total domestic 15,071,530 8,261,149 6,610,993 5,925,471 2,714,739 9,735,707 8,712,068 57,031,657 Foreign: Corporate (4) Normal obligors 14,087,409 3,571,416 3,236,191 1,392,231 550,082 1,228,924 5,906,045 29,972,298 Watch obligors excluding special attention obligors 316,387 179,555 73,656 55,876 28,325 25,384 122,410 801,593 Nonaccrual loans 35,801 1,622 13,743 17,181 14,743 22,639 9,745 115,474 Retail: Normal obligors 2,403 1,774 1,858 1,013 532 3,089 15 10,684 Watch obligors excluding special attention obligors — — 37 — — 13 — 50 Nonaccrual loans — — — — — — — — Sovereign: Normal obligors 278,373 6,856 33,225 15,194 174,298 3,079 74,923 585,948 Watch obligors excluding special attention obligors — — — — — — — — Nonaccrual loans — — 643 — — — — 643 Banks and other financial institutions: Normal obligors 1,003,709 254,232 150,505 224,571 12,041 709 120,088 1,765,855 Watch obligors excluding special attention obligors 5,544 — — — — — — 5,544 Nonaccrual loans 837 — — — — — — 837 Total foreign 15,730,463 4,015,455 3,509,858 1,706,066 780,021 1,283,837 6,233,226 33,258,926 Total 30,801,993 12,276,604 10,120,851 7,631,537 3,494,760 11,019,544 14,945,294 90,290,583 September 30, 2022 Term loans by origination year Revolving Loans Total 2022 2021 2020 2019 2018 Prior to 2018 (in millions of yen) Domestic: Corporate: Large companies: Normal obligors 7,870,700 7,071,371 5,977,206 4,621,144 3,938,164 4,418,492 7,791,782 41,688,859 Watch obligors excluding special attention obligors 65,982 73,932 63,547 84,634 68,093 74,857 129,011 560,056 Nonaccrual loans 78,466 56,229 71,920 121,977 38,086 133,924 174,556 675,158 Small and medium-sized Normal obligors 310,377 372,070 329,472 310,103 266,522 649,254 505,667 2,743,465 Watch obligors excluding special attention obligors 29,976 24,222 27,907 20,911 21,311 36,433 21,800 182,560 Nonaccrual loans 23,808 14,072 17,798 8,410 8,240 30,351 29,840 132,519 Retail: Housing Loan: Normal obligors 420,132 634,709 506,226 491,602 501,271 5,003,449 — 7,557,389 Watch obligors excluding special attention obligors 406 1,740 1,336 1,111 1,516 35,357 — 41,466 Nonaccrual loans 5,956 4,636 1,956 827 1,015 28,836 — 43,226 Others: Normal obligors 119,310 116,244 254,202 95,347 78,029 335,135 488,953 1,487,220 Watch obligors excluding special attention obligors 14,027 11,090 28,236 7,497 5,246 7,230 8,067 81,393 Nonaccrual loans 8,083 4,745 7,379 2,615 3,411 22,147 10,802 59,182 Sovereign: Normal obligors 950,117 190,195 103,654 94,458 98,581 367,373 — 1,804,378 Watch obligors excluding special attention obligors 4,517 2,538 3,464 321 291 — — 11,131 Nonaccrual loans — — — — — — — — Banks and other financial institutions: Normal obligors 74,820 17,641 23,286 136,043 244,377 143,685 133,705 773,557 Watch obligors excluding special attention obligors — — — — — — — — Nonaccrual loans — — — — — — — — Total domestic 9,976,677 8,595,434 7,417,589 5,997,000 5,274,153 11,286,523 9,294,183 57,841,559 Foreign: Corporate (4) Normal obligors 13,959,808 5,923,058 3,131,452 3,045,313 1,334,469 1,655,488 7,228,807 36,278,395 Watch obligors excluding special attention obligors 227,650 131,936 184,554 74,298 47,282 55,384 120,772 841,876 Nonaccrual loans 5,563 35,354 14,106 51,952 14,308 38,660 9,983 169,926 Retail: Normal obligors 1,221 1,868 1,733 1,850 941 3,278 13 10,904 Watch obligors excluding special attention obligors — — — — — 24 — 24 Nonaccrual loans — — — — — — — — Sovereign: Normal obligors 120,147 260,281 10,594 35,025 11,735 209,034 78,650 725,466 Watch obligors excluding special attention obligors — — — — — — — — Nonaccrual loans — — — 676 — — — 676 Banks and other financial institutions: Normal obligors 1,371,469 439,563 118,506 129,568 29,016 14,155 323,374 2,425,651 Watch obligors excluding special attention obligors 8,912 8,345 8,082 14,475 — — — 39,814 Nonaccrual loans — — — — — — — — Total foreign 15,694,770 6,800,405 3,469,027 3,353,157 1,437,751 1,976,023 7,761,599 40,492,732 Total 25,671,447 15,395,839 10,886,616 9,350,157 6,711,904 13,262,546 17,055,782 98,334,291 Notes: (1) Special attention obligors are watch obligors with debt in TDR or 90 days or more delinquent debt. Loans to such obligors are considered nonaccrual. (2) 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. (3) There were no significant revolving line of credit arrangements that converted to term loans during the fiscal year ended March 31, 2022 and the six months ended September 30, 2022. (4) Corporate of foreign include d we 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. 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 September 30, 2022, 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 period and no significant concentration of collateral against any portfolio segment. Nonaccrual loans 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. The Group classifies loans to special attention, intensive control, substantially bankrupt and bankrupt obligors as nonaccrual loans. Nonaccrual loans include loans past due for 90 days or more and restructured loans that meet the definition of a TDR in accordance with ASC 310, “Receivables” (“ASC 310”). 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 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 loans restructured in a TDR, in general, such loans are restored to accrual loans, and accrual status, when the borrower qualifies for an obligor rating of D or above. The table below presents nonaccrual loans information at March 31, 2022 and September 30, 2022: March 31, 2022 September 30, Amortized cost (1) Nonaccrual loans with an allowance Nonaccrual loans without an allowance Total nonaccrual loans Interest income recognized (2) (in millions of yen) Domestic: Corporate: Large companies 783,305 16,284 799,589 6,787 Small and medium-sized 121,598 18,962 140,560 867 Retail: Housing Loan 26,812 22,380 49,192 477 Others 40,155 21,678 61,833 406 Total domestic 971,870 79,304 1,051,174 8,537 Foreign: Total foreign 110,284 6,670 116,954 843 Total 1,082,154 85,974 1,168,128 9,380 September 30, 2022 September 30, Amortized cost (1) Nonaccrual loans with an allowance Nonaccrual loans without an allowance Total nonaccrual loans Interest income recognized (2) (in millions of yen) Domestic: Corporate: Large companies 657,323 17,835 675,158 10,009 Small and medium-sized companies 114,001 18,518 132,519 803 Retail: Housing Loan 23,491 19,735 43,226 399 Others 38,446 20,736 59,182 377 Total domestic 833,261 76,824 910,085 11,588 Foreign: Total foreign 162,601 8,001 170,602 1,572 Total 995,862 84,825 1,080,687 13,160 Notes: (1) Amounts represent the outstanding balances of nonaccrual loans. The MHFG Group’s policy for placing loans in nonaccrual status corresponds to 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 Troubled debt restructurings The MHFG Group considers a loan modification to be a TDR when, for economic or legal reasons related to the obligor’s financial difficulties, it grants a concession to the obligor that it would not otherwise consider. The Group considers the relevant obligor to be in financial difficulty generally when its obligor rating is E2 or below. The following table presents modified loans that were determined to be TDRs during the six months ended September 30, 2021 and 2022: Loan forgiveness or debt to equity swaps Interest rate reduction and/or postponement of principal and/or interest Recorded investment (1) Charge-offs (in millions of yen) September 30, 2021 Domestic: Corporate: Large companies 5,849 22,757 375,248 Small and medium-sized — — 60,856 Retail: Housing Loan — — 4,996 Others — — 10,288 Total domestic 5,849 22,757 451,388 Foreign: Total foreign — — 21,206 Total 5,849 22,757 472,594 September 30, 2022 Domestic: Corporate: Large companies — 140,371 256,773 Small and medium-sized — — 55,424 Retail: Housing Loan — — 3,257 Others — — 9,557 Total domestic — 140,371 325,011 Foreign: Total foreign — — 20,779 Total — 140,371 345,790 Notes: (1) Amounts represent the book values of loans immediately after the restructurings. (2) 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 six months ended September 30, 2021 and 2022 with respect to the loans modified as TDRs within the previous twelve months: Recorded investment September 30, 2021 September 30, 2022 (in millions of yen) Domestic: Corporate: Large companies 1,148 91,049 Small and medium-sized 2,157 626 Retail: Housing Loan 579 418 Others 515 722 Total domestic 4,399 92,815 Foreign: Total foreign 14,125 — Total 18,524 92,815 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, 2022 and September 30, 2022: 30-59 days past due 60-89 days past due 90 days or more past Total past due Current Total (in millions of yen) March 31, 2022 Domestic: Corporate: Large companies 323 291 27,275 27,889 42,016,051 42,043,940 Small and medium-sized 693 641 10,370 11,704 3,145,216 3,156,920 Retail: Housing Loan 15,181 8,326 16,548 40,055 7,741,465 7,781,520 Others 4,454 1,068 11,009 16,531 1,690,644 1,707,175 Sovereign — — — — 1,660,345 1,660,345 Banks and other financial institutions — — — — 681,757 681,757 Total domestic 20,651 10,326 65,202 96,179 56,935,478 57,031,657 Foreign: Total foreign — — 28,816 28,816 33,230,110 33,258,926 Total 20,651 10,326 94,018 124,995 90,165,588 90,290,583 September 30, 2022 Domestic: Corporate: Large companies 972 — 33,164 34,136 42,889,937 42,924,073 Small and medium-sized 809 — 11,330 12,139 3,046,405 3,058,544 Retail: Housing Loan 14,486 6,026 16,024 36,536 7,605,545 7,642,081 Others 4,582 1,030 11,130 16,742 1,611,053 1,627,795 Sovereign — — — — 1,815,509 1,815,509 Banks and other financial institutions — — — — 773,557 773,557 Total domestic 20,849 7,056 71,648 99,553 57,742,006 57,841,559 Foreign: Total foreign — — 49,946 49,946 40,442,786 40,492,732 Total 20,849 7,056 121,594 149,499 98,184,792 98,334,291 Note: The majority of total foreign consist of corporate. Net losses on sales of loans Net losses on sales of l o at of respectively.

Allowance for credit losses on

Allowance for credit losses on loans	6 Months Ended
	Sep. 30, 2022
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 six months ended September 30, 2021 and 2022 are Domestic Corporate Retail Sovereign Banks and Foreign ( 3 Total (in millions of yen) Six months ended September 30, 2021 Balance at beginning of period 481,420 83,171 68 623 85,567 650,849 Provision (credit) for credit losses on loans 54,150 (376 ) 13 (427 ) (5,155 ) 48,205 Charge-offs (1) (25,880 ) (2,446 ) — — (12,570 ) (40,896 ) Recoveries 5,312 916 — — 263 6,491 Net charge-offs (20,568 ) (1,530 ) — — (12,307 ) (34,405 ) Others ( 2 — — — — 579 579 Balance at end of period 515,002 81,265 81 196 68,684 665,228 Six months ended September 30, 2022 Balance at beginning of period 601,506 73,414 62 438 134,397 809,817 Provision (credit) for credit losses on loans 16,206 (1,078 ) (4 ) 230 23,185 38,539 Charge-offs (1) (146,204 ) (3,005 ) — — (14,403 ) (163,612 ) Recoveries 1,309 760 — — 1,939 4,008 Net charge-offs (144,895 ) (2,245 ) — — (12,464 ) (159,604 ) Others ( 2 — — — — 21,994 21,994 Balance at end of period 472,817 70,091 58 668 167,112 710,746 Notes: (1) Charge-offs increased by ¥122,716 million from the six months ended September 30, 2021 to ¥163,612 million for the six months ended September 30, 2022 due mainly to a debt waiver to a domestic corporate borrower. (2) Others includes primarily foreign exchange translation. (3) The majority of total foreign consist of corporate.

Other assets and liabilities

Other assets and liabilities	6 Months Ended
	Sep. 30, 2022
Other assets and liabilities	6. Other assets and liabilities The following table sets forth the details of other assets and liabilities at March 31, 2022 and September 30, 2022: March 31, 2022 September 30, 2022 (in millions of yen) Other assets: Accounts receivable: Receivables from brokers, dealers and customers for securities transactions 3,049,874 4,134,148 Other 557,842 438,670 Collateral pledged: Collateral pledged for derivative transactions 1,549,483 2,119,911 Margins provided for futures contracts 466,531 189,133 Other 1,006,849 1,086,446 Prepaid pension cost 762,147 747,563 Right-of-use 570,171 552,233 Security deposits 91,766 86,650 Loans held for sale 156,639 279,321 Other 775,940 885,359 Total 8,987,242 10,519,434 Other liabilities: Accounts payable: Payables to brokers, dealers and customers for securities transactions 1,406,965 1,662,194 Other 494,538 461,188 Guaranteed trust principal (Note) 810,776 821,670 Lease liabilities 593,339 574,190 Collateral accepted: Collateral accepted for derivative transactions 1,075,591 1,744,164 Margins accepted for futures contracts 327,883 131,007 Unearned income 113,181 109,425 Other 1,437,949 1,516,457 Total 6,260,222 7,020,295 Note: 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 15 “Variable interest entities and securitizations” for further discussion of the guaranteed principal money trusts.

Preferred and common stock

Preferred and common stock	6 Months Ended
	Sep. 30, 2022
Preferred and common stock	7. Preferred and common stock Preferred stock The composition of preferred stock at March 31, 2022 and September 30, 2022 is as follows: Class of stock March 31, 2022 September 30, 2022 Authorized Issued Authorized Issued (number of shares) Class XIV preferred stock 90,000,000 — 90,000,000 — Class XV preferred stock 90,000,000 — 90,000,000 — Class XVI preferred stock 150,000,000 — 150,000,000 — Common stock The number of issued shares of common stock at March 31, 2022 and September 30, 2022 was 2,539,249,894. There was no increase or decrease during the six months ended September 30, 2022.

Accumulated other comprehensive

Accumulated other comprehensive income (loss), net of tax	6 Months Ended
	Sep. 30, 2022
Accumulated other comprehensive income (loss), net of tax	8. Accumulated other comprehensive income (loss), net of tax Changes in each component of Accumulated other comprehensive income (loss), net of tax (“AOCI”) for the six months ended September 30, 2021 and 2022 are as follows: Six months ended September 30, 2021 2022 (in millions of yen) AOCI, balance at beginning of period 318,114 440,112 Net unrealized gains (losses) on available-for-sale Balance at beginning of period (8,173 ) (25,046 ) Unrealized holding gains (losses) during period 6,034 (4,329 ) Less: reclassification adjustments for losses (gains) included in net income (525 ) (4,741 ) Change during period 5,509 (9,070 ) Balance at end of period (2,664 ) (34,116 ) Foreign currency translation adjustments: Balance at beginning of period (86,873 ) 94,104 Foreign currency translation adjustments during period 52,231 269,154 Less: reclassification adjustments for losses (gains) included in net income — — Change during period 52,231 269,154 Balance at end of period (34,642 ) 363,258 Defined benefit plan adjustments: Balance at beginning of period 397,153 355,355 Unrealized gains (losses) during period (5,107 ) 4,390 Less: reclassification adjustments for losses (gains) included in net income (9,187 ) (9,183 ) Change during period (14,294 ) (4,793 ) Balance at end of period 382,859 350,562 Own credit risk adjustments: Balance at beginning of period 16,007 15,699 Unrealized gains (losses) during period (6,218 ) 2,998 Less: reclassification adjustments for losses (gains) included in net income 443 434 Change during period (5,775 ) 3,432 Balance at end of period 10,232 19,131 Total other comprehensive income (loss), net of tax attributable to MHFG shareholders 37,671 258,723 AOCI, balance at end of period 355,785 698,835 The following table shows the amounts reclassified out of AOCI into net income during the six months ended September 30, 2022: Six months ended September 30, 2022 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 into net income: Affected line items in the consolidated statements of Net unrealized gains (losses) on available-for- 6,759 (2,018 ) 4,741 — 4,741 Investment gains (losses)-net Defined benefit plan adjustments 13,114 (3,940 ) 9,174 9 9,183 Salaries and employee Own credit risk adjustments (626 ) 192 (434 ) — (434 ) Other noninterest income Total 19,247 (5,766 ) 13,481 9 13,490 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) (loss),

Regulatory matters

Regulatory matters	6 Months Ended
	Sep. 30, 2022
Regulatory matters	9. 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. Capital adequacy ratios and leverage ratios of MHFG, MHBK, and MHTB as of March 31, 2022 and September 30, 2022 calculated in accordance with Japanese GAAP and the guidelines established by the Financial Services Agency are set forth in the following table: March 31, 2022 September 30, 2022 Amount Ratio Amount Ratio (in billions of yen, except percentages) Consolidated: MHFG: Common Equity Tier 1 capital: Required (1) 5,184 8.01 5,714 8.01 Actual 8,067 12.46 8,097 11.35 Tier 1 capital: Required (1) 6,155 9.51 6,784 9.51 Actual 9,713 15.00 9,733 13.64 Total risk-based capital: Required (1) 7,450 11.51 8,210 11.51 Actual 11,351 17.53 11,216 15.72 Leverage Ratio (2) Required 6,389 3.00 6,925 3.00 Actual 9,713 4.56 9,733 4.21 MHBK: Common Equity Tier 1 capital: Required 2,683 4.50 2,981 4.50 Actual 6,968 11.68 7,082 10.68 Tier 1 capital: Required 3,578 6.00 3,975 6.00 Actual 8,604 14.42 8,714 13.15 Total risk-based capital: Required 4,771 8.00 5,300 8.00 Actual 10,150 17.02 10,110 15.26 Leverage Ratio (2) Required 5,971 3.00 6,509 3.00 Actual 8,604 4.32 8,714 4.01 MHTB: Common Equity Tier 1 capital: Required 79 4.50 76 4.50 Actual 442 25.18 453 26.62 Tier 1 capital: Required 105 6.00 102 6.00 Actual 442 25.18 453 26.62 Total risk-based capital: Required 140 8.00 136 8.00 Actual 442 25.18 453 26.62 Leverage Ratio (2) Required 130 3.00 128 3.00 Actual 442 10.20 453 10.56 March 31, 2022 September 30, 2022 Amount Ratio Amount Ratio (in billions of yen, except percentages) Non-consolidated: MHBK: Common Equity Tier 1 capital: Required 2,528 4.50 2,783 4.50 Actual 6,293 11.20 6,066 9.80 Tier 1 capital: Required 3,370 6.00 3,710 6.00 Actual 7,919 14.09 7,689 12.43 Total risk-based capital: Required 4,494 8.00 4,947 8.00 Actual 9,483 16.88 9,097 14.70 Leverage Ratio (2) Required 5,570 3.00 6,048 3.00 Actual 7,919 4.26 7,689 3.81 MHTB: Common Equity Tier 1 capital: Required 78 4.50 76 4.50 Actual 425 24.40 436 25.68 Tier 1 capital: Required 104 6.00 101 6.00 Actual 425 24.40 436 25.68 Total risk-based capital: Required 139 8.00 135 8.00 Actual 425 24.40 436 25.69 Leverage Ratio (2) Required 126 3.00 124 3.00 Actual 425 10.09 436 10.47 Notes: (1) The required ratios disclosed above, at March 31, 2022 and September 30, 2022, include the capital conservation buffer of 2.5%, the countercyclical capital buffer of 0.01%, and the additional loss absorbency requirements for global systemically important banks (“G-SIBs”) (“D-SIBs”) (2) The required and actual amounts disclosed above at March 31, 2022 and September 30, 2022 exclude amounts of deposits to the Bank of Japan. MHFG’s securities subsidiary in Japan is also subject to the capital adequacy requirement under Japan’s Financial Instruments and Exchange Act. Failure to maintain a minimum capital ratio will trigger mandatory regulatory actions. 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. Business improvement orders MHFG and MHBK received business improvement orders dated November 26, 2021 from the Financial Services Agency of Japan pursuant to Clause 1 of Article 52-33

Earnings per common share

Earnings per common share	6 Months Ended
	Sep. 30, 2022
Earnings per common share	10. Earnings per common share Basic earnings per common share are computed by dividing net income (loss) attributable to MHFG common shareholders by the weighted average number of common shares outstanding during the period. Diluted earnings per common share reflect all dilutive potential common shares such as stock options and the common shares of MHFG under the stock compensation programs. The following table sets forth the computation of basic and diluted earnings per common share for the six months ended September 30, 2021 and 2022: Six months ended 2021 2022 (in millions of yen) Net income (loss): Net income (loss) attributable to MHFG common shareholders 312,657 (378,877 ) Effect of dilutive securities — — Net income (loss) attributable to common shareholders after assumed conversions 312,657 (378,877 ) Six months ended September 30, 2021 2022 (thousands of shares) Shares: Weighted average common shares outstanding 2,536,902 2,536,315 Effect of dilutive securities: Stock options and the common shares of MHFG under the stock compensation programs (Note) 119 — Weighted average common shares after assumed conversions 2,537,021 2,536,315 Six months ended September 30, 2021 2022 (in yen) Earnings per common share: Basic net income (loss) per common share 123.24 (149.38 ) Diluted net income (loss) per common share (Note) 123.24 (149.38 ) Note: For the six months ended September 30, 2022, 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 six months ended September 30, 2022, 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	6 Months Ended
	Sep. 30, 2022
Income taxes	11. Income taxes The following table presents the components of Income tax expense (benefit) for the six months ended September 30, 2021 and 2022: Six months ended 2021 2022 (in millions of yen) Current tax expense 67,822 67,244 Deferred tax expense (benefit) (28,200 ) (239,149 ) Total income tax expense (benefit) 39,622 (171,905 ) The preceding table does not reflect the tax effects of items recorded directly in Equity for the six months ended September 30, 2021 and 2022. The detailed amounts recorded directly in Equity are as follows: Six months ended 2021 2022 (in millions of yen) Net unrealized gains (losses) on available-for-sale Unrealized gains (losses) 926 (3,413 ) Less: reclassification adjustments (213 ) (2,018 ) Total 713 (5,431 ) Defined benefit plan adjustments: Unrealized gains (losses) (2,144 ) 1,381 Less: reclassification adjustments (3,875 ) (3,940 ) Total (6,019 ) (2,559 ) Own credit risk adjustments: Unrealized gains (losses) (2,638 ) 1,368 Less: reclassification adjustments 219 192 Total (2,419 ) 1,560 Total tax effect before allocation to noncontrolling interests (7,725 ) (6,430 ) The statutory tax rates were both 30.62 % as of September 30 , and 2022 . The effective tax rates, 10.34 % and 30.55 % for the six months ended September 30, 2021 and 2022, respectively, differed from the statutory tax rates. The significant difference of the tax rate for the six months ended September 30, 2021 resulted mainly from 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 was partially offset by an increase in the valuation allowance. The difference of the tax rates for the six months ended September 30, 2022 was immaterial. At September 30, 2022, the MHFG Group had net operating loss carryforwards totaling ¥571 billion. The total amount of unrecognized tax benefits was ¥ million at September 30, 2022, which would, if recognized, affect the Group’s effective tax rate. The Group classifies interest and p en An immaterial portion of unrecognized tax benefits at March 31, 2022 was resolved in the six months period ended September 30, 2022. The amount of additional unrecognized tax benefits for the period was also immaterial. The MHFG 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	6 Months Ended
	Sep. 30, 2022
Pension and other employee benefit plans	12. Pension and other employee benefit plans The following table summarizes the components of net periodic benefit cost of the severance indemnities and pension plans of the MHFG Group for the six months ended September 30, 2021 and 2022: Six months ended September 30, 2021 2022 (in millions of yen) Service cost-benefits earned during the period 16,365 14,559 Interest costs on projected benefit obligations 2,700 3,626 Expected return on plan assets (18,478 ) (18,050 ) Amortization of prior service cost (benefits) (2,410 ) (2,410 ) Amortization of net actuarial loss (gain) (10,263 ) (9,741 ) Special termination benefits 4,154 3,831 Net periodic benefit cost (7,932 ) (8,185 )

Derivative financial instrument

Derivative financial instruments	6 Months Ended
	Sep. 30, 2022
Derivative financial instruments	13. 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, 2022 and September 30, 2022. 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) March 31, 2022 Notional amount (1) Designated as hedges Not designated as hedges Designated as hedges Not designated as hedges (in billions of yen) Interest rate contracts 1,395,950 — 4,624 — 4,716 Foreign exchange contracts 217,462 — 4,436 — 4,472 Equity-related contracts 9,887 — 426 — 345 Credit-related contracts 11,857 — 118 — 121 Other contracts 681 — 119 — 116 Total 1,635,837 — 9,723 — 9,770 Fair value Derivative receivables (2) Derivative payables (2) September 30, 2022 Notional amount (1) Designated as hedges Not designated as hedges Designated as hedges Not designated as hedges (in billions of yen) Interest rate contracts 1,627,102 — 8,916 — 9,229 Foreign exchange contracts 260,472 — 8,571 — 8,665 Equity-related contracts 7,735 — 285 — 214 Credit-related contracts 21,379 — 166 — 94 Other contracts 1,116 — 92 — 92 Total 1,917,804 — 18,030 — 18,294 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 ¥ billion and ¥ billion at March 31, 2022, and ¥ billion and ¥ billion at September 30, 2022, 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 six months ended September 30, 2021 and 2022: Gains (losses) recorded in income for six months ended September 30, 2021 2022 (in millions of yen) Interest rate contracts 20,602 (179,783 ) Foreign exchange contracts 7,407 251,060 Equity-related contracts 33,504 482,233 Credit-related contracts (Note) (15,599 ) 42,152 Other contracts 6,875 61,001 Total 52,789 656,663 Note: Amounts include the net gains (losses) of ¥(395) million and ¥172 million on the credit derivatives economically managing the credit risk of loans during the six months ended September 30, 2021 and 2022, 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, 2022 and September 30, 2022: March 31, 2022 September 30, 2022 Notional amount Fair value Notional amount Fair value (in billions of yen) Credit protection written: Investment grade 3,045 38 4,370 — Non-investment 2,122 54 5,496 (41 Total 5,167 92 9,866 (41 Credit protection purchased 6,690 (95 ) 11,513 113 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, 2022 and September 30, 2022: Maximum payout/Notional amount March 31, 2022 September 30, 2022 (in billions of yen) One year or less 245 242 After one year through five years 4,785 9,239 After five years 137 385 Total 5,167 9,866 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, 2022 and September 30, 2022: March 31, 2022 September 30, 2022 (in billions of yen) Aggregate fair value of derivative instruments with credit-risk-related contingent features in net liability positions 1,149 1,866 Collateral provided to counterparties in the normal course of business 1,164 1,743 Amount required to be posted as collateral or settled immediately if credit-risk-related contingent features were triggered — 123 Note: There was no amount that the Group would be required to post as collateral or settle immediately on March 31, 2022.

Commitments and contingencies

Commitments and contingencies	6 Months Ended
	Sep. 30, 2022
Commitments and contingencies	14. 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 Group records all guarantees and similar obligations subject to ASC 460, “Guarantees” (“ASC 460”) at fair value in the consolidated balance sheets at the inception of the guarantee. The table below summarizes the maximum potential amount of future payments by type of guarantee at March 31, 2022 and September 30, 2022. 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. March 31, 2022 September 30, 2022 (in billions of yen) Performance guarantees 3,254 3,612 Guarantees on loans 419 409 Guarantees on securities 75 89 Other guarantees 2,899 3,683 Guarantees for the repayment of trust principal 22 19 Liabilities of trust accounts 478 529 Derivative financial instruments 36,484 44,900 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, 2022 and September 30, 2022: March 31, 2022 September 30, 2022 (in billions of yen) Investment grade 5,336 6,228 Non-investment grade 1,311 1,565 Total 6,647 7,793 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 The table below summarizes the contractual amounts with regard to these undrawn commitments at March 31, 2022 and September 30, 2022: March 31, 2022 September 30, 2022 (in billions of yen) Commitments to extend credit (Note) 92,203 99,960 Commercial letters of credit 1,422 1,601 Total 93,625 101,561 Note: Commitments to extend credit include commitments to invest in securities. 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, “Contingencies” (“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.

Variable interest entities and

Variable interest entities and securitizations	6 Months Ended
	Sep. 30, 2022
Text Block [Abstract]
Variable interest entities and securitizations	15. 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 MHFG 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 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, 2022 and September 30, 2022: Consolidated VIEs Significant March 31, 2022 Consolidated assets Total assets Maximum (in billions of yen) Asset-backed commercial paper/loan programs 2,709 — — Asset-backed securitizations 1,363 190 90 Investments in securitization products 388 — — Investment funds 1,816 3,392 719 Trust arrangements and other 5,299 — — Total 11,575 3,582 809 Consolidated VIEs Significant unconsolidated VIEs September 30, 2022 Consolidated assets Total assets Maximum exposure to (in billions of yen) Asset-backed commercial paper/loan programs 2,991 — — Asset-backed securitizations 1,653 199 121 Investments in securitization products 387 — — Investment funds 2,060 2,952 688 Trust arrangements and other 5,084 — — Total 12,175 3,151 809 As of March 31, 2022 and September 30, 2022, the noncontrolling interests in consolidated VIEs amounted to ¥388 billion and ¥641 billion, respectively, and are included in the Group’s equity-classified noncontrolling interests. The 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, 2022 and September 30, 2022: Assets on the MHFG Group’s balance sheets related to unconsolidated VIEs: March 31, 2022 September 30, 2022 (in billions of yen) Trading account assets 143 152 Investments 430 373 Loans 92 115 Total 665 640 Liabilities on the MHFG Group’s balance sheets and maximum exposure to loss related to March 31, 2022 September 30, 2022 (in billions of yen) Payables under securities lending transactions 54 59 Trading account liabilities 2 2 Total 56 61 Maximum exposure to loss (Note) 809 809 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 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 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 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 MHFG Group also arranges securitization transactions including CMBS, RMBS and others. In these transactions, the MHFG 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 MHFG 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 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 MHFG 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 MHFG 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 MHFG 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 MHFG Group does not consolidate certain guaranteed principal money trusts, which invest all the entrusted funds in the MHFG Group itself, as the Group has determined that it has no variable interests. See Note 14 “Commitments and contingencies” for the balances of guaranteed trust principal that are not consolidated at March 31, 2022 and September 30, 2022. With respect to non-guaranteed non-guaranteed The MHFG Group has established a trust in August 2020, which holds the Group’s housing loans and in turn issues beneficiary interests to the Group, as a result from Special Funds-Supplying Operations implemented by the Bank of Japan to facilitate financing in response to COVID-19. 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 has established several 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, “Transfers and Servicing” (“ASC860”) 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 six months ended September 30, 2021 and 2022, the MHFG Group neither made significant transfers of financial assets nor recognized significant gains or losses in securitization transactions accounted for as sales. The Group did not retain significant interests in securitization transactions accounted for as sales as of March 31, 2022 and September 30, 2022. There are certain transactions where transfers of financial assets do not qualify for the aforementioned sales criteria and are accounted for as secured borrowings. These transferred assets continue to be carried on the consolidated balance sheets of the MHFG Group. Such assets are associated with securitization transactions and loan participation transactions, which amounted to ¥ billion and ¥ billion as of March 31, 2022, and ¥ billion and ¥ billion as of September 30, 2022, respectively. Liabilities associated with securitization and loan participation transactions are presented as Payables under securities lending transactions and Other short-term borrowings or Long-term debt, respectively, on the

Noninterest income

Noninterest income	6 Months Ended
	Sep. 30, 2022
Noninterest income	16. Noninterest income Details of Noninterest income for the six months ended September 30, 2021 and 2022 are as follows: Six months ended September 30, 2021 2022 (in millions of yen) Fee and commission income: Securities-related business (1) 89,387 74,804 Deposits-related business (1) 7,569 7,769 Lending-related business (2)(4) 78,053 79,811 Remittance business (1) 54,576 52,410 Asset management business (1) 60,596 55,508 Trust-related business (1) 66,393 57,395 Agency business (1) 18,573 18,399 Guarantee-related business (3) 16,781 20,680 Fees for other customer services (1) 82,988 81,968 Total Fee and commission income 474,916 448,744 Foreign exchange gains (losses)—net (3) 21,708 128,897 Trading account gains (losses)—net (2) 83,255 (851,080 ) Investment gains (losses)—net: Debt securities (3) (317 ) 8,057 Equity securities (3) 135,070 (113,461 ) Equity in earnings (losses) of equity method investees—net (3) 16,541 (5,003 ) Gains on disposal of premises and equipment (3) 1,988 1,811 Other noninterest income (2)(5) 29,234 168,254 Total 762,395 (213,781 ) 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 17 “Fair value” for further details. Certain Fee and commission income, Trading account gains (losses)-net 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” to the consolidated financial statements in the Group’s most recent Form 20-F. 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 ¥28 billion and ¥38 billion for the six months ended September 30, 2021, respectively, and ¥27 billion and ¥30 billion for the six months ended September 30, 2022, respectively. Trading account gains (losses)-net In addition to Fee and commission income, Trading account gains (losses)-net (losses)-net. 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, 2022 and September 30, 2022, the balance of contract assets was not material. Contract liabilities are recognized in unearned income of Other liabilities. As of March 31, 2022 and September 30, 2022, 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, 2022 and September 30, 2022, 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.

Fair value

Fair value	6 Months Ended
	Sep. 30, 2022
Fair value	17. Fair value Fair value measurements ASC 820, “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 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 check and verify 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 used 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 six months ended September 30, 2022, 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 period. 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 currency swaps and option contracts. Derivative contracts valued using significant unobservable correlation or volatility are classified in Level 3 of the fair value hierarchy. In addition, the Group records credit-risk valuation adjustments on over-the-counter over-the-counter 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 Long-term debt Fair value accounting is elected for certain long-term 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 Items measured at fair value on a recurring basis Assets and liabilities measured at fair value on a recurring basis at March 31, 2022 and September 30, 2022, including those for which the MHFG Group has elected the fair value option, are summarized below: March 31, 2022 Level 1 Level 2 Level 3 Assets/ Liabilities measured at fair value (in billions of yen) Assets: Trading securities (1) Japanese government bonds 1,604 11 — 1,615 Japanese local government bonds — 145 — 145 U.S. Treasury bonds and federal agency securities 2,353 711 — 3,064 Other foreign government bonds 907 639 — 1,546 Agency mortgage-backed securities — 3,176 — 3,176 Residential mortgage-backed securities — — 8 8 Certificates of deposit and commercial paper — 640 — 640 Corporate bonds and other (2) 15 2,743 71 2,829 Equity securities 1,381 213 28 1,622 Trading securities measured at net asset value (3) 284 Derivative financial instruments: Interest rate contracts 89 4,513 22 4,624 Foreign exchange contracts — 4,404 32 4,436 Equity-related contracts 77 323 26 426 Credit-related contracts — 116 2 118 Other contracts 49 18 52 119 Available-for-sale Japanese government bonds 24,662 497 — 25,159 Japanese local government bonds — 420 — 420 U.S. Treasury bonds and federal agency securities 373 — — 373 Other foreign government bonds 363 973 — 1,336 Agency mortgage-backed securities — 451 — 451 Residential mortgage-backed securities — 40 18 58 Commercial mortgage-backed securities — 854 — 854 Japanese corporate bonds and other debt securities — 1,920 315 2,235 Foreign corporate bonds and other debt securities — 671 117 788 Equity securities: Equity securities with readily determinable fair values 3,094 61 — 3,155 Equity securities measured at net asset value (3) 210 Other investments 2 — 56 58 Total assets measured at fair value on a recurring basis 34,969 23,539 747 59,749 Liabilities: Trading securities sold, not yet purchased 3,054 2,035 — 5,089 Derivative financial instruments: Interest rate contracts 80 4,636 — 4,716 Foreign exchange contracts — 4,472 — 4,472 Equity-related contracts 122 183 40 345 Credit-related contracts — 120 1 121 Other contracts 28 36 52 116 Long-term debt (4) — 1,962 794 2,756 Total liabilities measured at fair value on a recurring basis 3,284 13,444 887 17,615 September 30, 2022 Level 1 Level 2 Level 3 Assets/ Liabilities measured at fair value (in billions of yen) Assets: Trading securities (1) Japanese government bonds 1,858 11 — 1,869 Japanese local government bonds — 99 — 99 U.S. Treasury bonds and federal agency securities 2,908 1,129 — 4,037 Other foreign government bonds 863 836 — 1,699 Agency mortgage-backed securities — 4,068 — 4,068 Residential mortgage-backed securities — — 7 7 Certificates of deposit and commercial paper — 797 — 797 Corporate bonds and other (2) 83 2,603 71 2,757 Equity securities 1,621 181 26 1,828 Trading securities measured at net asset value (3) 140 Derivative financial instruments: Interest rate contracts 202 8,663 51 8,916 Foreign exchange contracts — 8,529 42 8,571 Equity-related contracts 96 161 28 285 Credit-related contracts — 164 2 166 Other contracts 36 18 38 92 Available-for-sale Japanese government bonds 16,366 737 — 17,103 Japanese local government bonds — 497 — 497 U.S. Treasury bonds and federal agency securities 435 — — 435 Other foreign government bonds 279 1,001 — 1,280 Agency mortgage-backed securities — 494 — 494 Residential mortgage-backed securities — 37 15 52 Commercial mortgage-backed securities — 869 — 869 Japanese corporate bonds and other debt securities — 1,992 130 2,122 Foreign corporate bonds and other debt securities — 731 161 892 Equity securities: Equity securities with readily determinable fair values 2,913 55 — 2,968 Equity securities measured at net asset value (3) 278 Other investments — — 64 64 Total assets measured at fair value on a recurring basis 27,660 33,672 635 62,385 Liabilities: Trading securities sold, not yet purchased 2,602 3,333 — 5,935 Derivative financial instruments: Interest rate contracts 185 9,043 1 9,229 Foreign exchange contracts — 8,662 3 8,665 Equity-related contracts 69 95 50 214 Credit-related contracts — 90 4 94 Other contracts 28 26 38 92 Long-term debt (4) — 1,930 806 2,736 Total liabilities measured at fair value on a recurring basis 2,884 23,179 902 26,965 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, 2022 and September 30, 2022 were ¥68 billion and ¥61 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 basis using Six months ended September 30, 2021 April 1, 2021 Gains (losses) in Earnings Gains (losses) in OCI Transfers into Level 3 Transfers out of Level 3 Purchases Sales Issuances Settle- ments September 30, 2021 Change in unrealized gains (losses) still held (6) (in billions of yen) Assets: Trading securities: Residential mortgage-backed securities 9 — (2) — — — — — — (1 ) 8 — Corporate bonds and other 1,033 4 (2) — — (1 ) 232 (144 ) — (298 ) 826 5 Equity securities 29 1 (2) — — — — — — — 30 1 Derivative financial instruments, net (1) Interest rate contracts 8 (5 ) (2) — — — — — — 2 5 (5 ) Foreign exchange contracts 23 (1 ) (2) — — — — — — — 22 (2 ) Equity-related contracts (21 ) (14 ) (2) — — — — — — (4 ) (39 ) (22 ) Credit-related contracts 2 (1 ) (2) — (1 ) — — — — 1 1 1 Other contracts — 1 (2) — — — — — — — 1 — Available-for-sale Residential mortgage-backed securities 23 — (3) — (4) — — — — — (3 ) 20 — Commercial mortgage-backed securities 716 — (3) — (4) — — 63 (6 ) — (7 ) 766 — Japanese corporate bonds and other debt 365 2 (3) — (4) — — 8 — — (28 ) 347 2 Foreign corporate bonds and other debt securities 132 — (3) (3 ) (4) — — 19 — — (31 ) 117 — Other investments 53 (1 ) (3) — — — 34 (1 ) — (32 ) 53 (2 ) Liabilities: Trading securities sold, not yet purchased — — (2) — — — (1 ) 1 — — — — Long-term debt 713 6 (5) (5 ) (4) 1 (1 ) — — 256 (216 ) 752 9 Six months ended September 30, 2022 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 September 30, 2022 Change in unrealized gains (losses) still held (6) (in billions of yen) Assets: Trading securities: Residential mortgage-backed securities 8 — (2) — — — — — — (1 ) 7 — Corporate bonds and other 71 6 (2) — 8 (1 ) 65 (29 ) — (49 ) 71 1 Equity securities 28 1 (2) — — — — — — (3 ) 26 (1 ) Derivative financial instruments, net (1) : Interest rate contracts 22 24 (2) — — — — — — 4 50 (27 ) Foreign exchange contracts 32 7 (2) — — — — — — — 39 4 Equity-related contracts (14 ) (12 ) (2) — — — — — — 4 (22 ) (129 ) Credit-related contracts 1 (2 ) (2) — — — — — — (1 ) (2 ) (6 ) Other contracts — — (2) — — — — — — — — — Available-for-sale Residential mortgage-backed securities 18 — (3) — (4) — — — — — (3 ) 15 — Commercial mortgage-backed securities — — (3) — (4) — — — — — — — — Japanese corporate bonds and other debt 315 — (3) — (4) — — 3 — — (188 ) 130 5 Foreign corporate bonds and other debt 117 — (3) 1 (4) — (9 ) 54 — — (2 ) 161 — Other investments 56 3 (3) — — — 36 — — (31 ) 64 — Liabilities: Trading securities sold, not yet purchased — — (2) — — — — — — — — — Long-term debt 794 96 (5) 6 (4) 1 — — — 201 (88 ) 806 109 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, (losses)-net (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 OCI 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 September 30, 2021 and 2022. The amounts of unrealized gains (losses) in OCI are related to Available-for-sale billion and ¥(5) billion, respectively, at September 30, 2021, and ¥5 billion and ¥ 6 Transfers between levels During the six months ended September 30, 2021, the transfers into Level 3 included ¥1 billion of net Derivative liabilities and ¥1 billion of Long-term debt. Transfers into Level 3 for net Derivative liabilities were primarily due to changes in the observability of the inputs used to measure fair value of certain credit-related derivatives. Transfers into Level 3 for Long-term debt were primarily due to changes in the observability of the default rate when valuing certain structured notes. During the six months ended September 30, 2021, the transfers out of Level 3 included ¥1 billion of Trading securities and ¥1 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 Long-term debt were primarily due to changes in the observability of the default rate when valuing certain structured notes. During the six months ended September 30, 2022, the transfers into Level 3 included ¥ 8 billion of Trading securities and ¥ 1 billion of Long-term debt. Transfers into Level 3 for Trading securities were primarily due to decreased liquidity for certain foreign bonds. Transfers into Level 3 for Long-term debt were primarily due to changes in the observability of the default rate when valuing certain structured notes. During the six months ended September 30, 2022, the transfers out of Level 3 included ¥ 1 billion of Trading securities and ¥ 9 billion of Available-for-sale securities. 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 securities were primarily due to increased liquidity for certain Foreign corporate bonds and other debt securities. 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, 2022 and September 30, 2022: March 31, 2022 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 26 Discounted cash flow Prepayment rate Default rate Recovery rate Discount margin 0% - 18% 0% - 0% 100% - 100% 30bps - 167bps 6% 0% 100% 53bps Corporate bonds and other debt securities 503 Discounted cash flow Prepayment rate (1) Default rate (1) Recovery rate (1) Discount margin (1) Discount margin (2) 6% - 24% 0% - 60% 10% - 40% 35bps - 103bps 4bps - 447bps 24% 1% 39% 47bps 340bps Derivative financial instruments, net: Interest rate contracts 22 Internal valuation model (3) IR - IR correlation 23% - 100% 75% Foreign exchange contracts 32 Internal valuation model (3) FX - IR correlation FX - FX correlation 11% - 52% 41% - 65% 31% 53% Equity-related contracts (14 ) Internal valuation model (3) Equity - IR correlation Equity correlation Equity volatility 25% - 25% 3% - 100% 13% - 121% 25% 90% 47% Credit-related contracts 1 Internal valuation model (3) Default rate Credit correlation 0% - 8% 43% - 100% 1% 66% Other contracts — Internal valuation model (3) Commodity volatility 0% - 89% 55% Long-term debt 794 Internal valuation model (3) IR - IR correlation FX - IR correlation FX - FX correlation Equity - IR correlation Equity - FX correlation Equity correlation Equity volatility Default rate Credit correlation 23% - 100% 11% - 52% 41% - 65% 25% - 25% -17% - 17% 3% - 100% 9% - 121% 0% - 8% 19% - 100% 75% 39% 53% 25% 0% 90% 34% 1% 64% September 30, 2022 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 22 Discounted cash flow Price-based Prepayment rate Default rate Recovery rate Discount margin 0% - 17% 0% - 2% 100% - 100% 30bps - 167bps 5% 0% 100% 51bps Corporate bonds and other debt securities 362 Discounted cash flow Price-based Prepayment rate (1) Default rate (1) Recovery rate (1) Discount margin (1) Discount margin (2) 26% - 26% 0% - 0% 40% - 40% 63bps - 127bps 4bps - 441bps 26% 0% 40% 74bps 26bps Derivative financial instruments, net: Interest rate contracts 50 Internal valuation model (3) IR - IR correlation 23% - 100% 75% Foreign exchange contracts 39 Internal valuation model (3) FX - IR correlation FX - FX correlation 5% - 55% 41% - 65% 38% 53% Equity-related contracts (22 ) Internal valuation model (3) Equity - IR correlation Equity correlation Equity volatility 25% - 25% 3% - 100% 10% - 181% 25% 91% 54% Credit-related contracts (2 ) Internal valuation model (3) Default rate 0% - 13% 2% Other contracts — Internal valuation model (3) Commodity volatility 0% - 65% 49% Long-term debt 806 Internal valuation model (3) IR - IR correlation FX - IR correlation FX - FX correlation Equity - IR correlation Equity - FX correlation Equity correlation Equity volatility Default rate Credit correlation 23% - 100% 5% - 55% 41% - 65% 25% - 25% -17% - 17% 3% - 10% - 181% 0% - 13% 23% - 100% 75% 40% 53% 25% 0% 90% 37% 3% 65% 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. 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, 2022 and September 30, 2022: March 31, 2022 Total Level 1 Level 2 Level 3 Aggregate cost (in billions of yen) Assets: Loans 81 — — 81 128 Loans held-for-sale 76 — 27 49 77 Equity securities (without readily determinable fair values) 4 — 3 1 4 Premises and equipment-net — — — — 13 Other assets — — — — 3 Total assets measured at fair value on a nonrecurring basis 161 — 30 131 225 September 30, 2022 Total Level 1 Level 2 Level 3 Aggregate cost (in billions of yen) Assets: Loans 94 — — 94 166 Loans held-for-sale 177 — 51 126 192 Equity securities (without readily determinable fair values) 1 — 1 — 1 Other investments 132 132 — — 161 Premises and equipment-net — — — — 1 Total assets measured at fair value on a nonrecurring basis 404 132 52 220 521 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 became nonaccrual and are measured based upon the observable market price of the loan, which is classified as Level 2, or the fair value of the underlying collateral, which is classified as Level 3. Loans held-for-sale Equity securities (without readily determinable fair values) in the table above consist of non-marketable non-marketable non-marketable 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. There were no other investments measured at fair value on a nonrecurring basis as of March 31, 2022. Premises and equipment—net and Other assets in the table above have been impaired and written down to fair value. There were no other assets measured at fair value on a nonrecurring basis as of September 30, 2022. 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 Long-term debt and interest on these notes continues to be reported in Interest expense on long-term debt based on the contractual rates. Only an immaterial amount included in 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 ¥90 billion and ¥221 billion at March 31, 2022 and September 30, 2022, respectively. The net unrealized gains (losses) resulting from changes in fair values of these notes recorded in Other noninterest income (expenses) were of ¥(30) billion and ¥128 billion for the six months ended September 30, 2021 and 2022, 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 estimation methods are described in more detail below. These estimates could be significantly affected by different sets of assumptions. There are certain limitations to management’s best judgment in estimating fair values of financial instruments and inherent subjectivity involved in estimation methodologies and assumptions used to estimate fair value. Accordingly, the net realizable or liquidation values could be materially different from the estimates presented below. The following is a description of the valuation methodologies used for estimating the fair value of financial assets and liabilities not carried at fair value on the MHFG Group’s consolidated balance sheets. 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 The carrying value of short-term financial assets, such as 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 approximates the fair value of these assets since they generally involve limited losses from credit risk or have short-term maturities with interest rates that approximate market rates. Investments The fair value of held-to-maturity available-for-sale non-marketable Loans Loans have been fair valued based on the type of loan, credit quality, prepayment assumptions and remaining maturity. The fair value of loans is determined based on discounted cash flows using interest rates approximating the MHFG Group’s current rates for similar loans. The fair value of collateral dependent nonaccrual loans is determined based on the fair value of the underlying collateral. Other financial assets The carrying value of other financial as

Offsetting of financial assets

Offsetting of financial assets and financial liabilities	6 Months Ended
	Sep. 30, 2022
Offsetting of financial assets and financial liabilities	18. 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, 2022 and September 30, 2022. 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. Amounts not offset on the balance sheet (3) Gross amounts recognized Gross amounts offset on the balance sheet Net amounts presented on the balance sheet (2) Financial instruments (4) Cash collateral Net amounts (in billions of yen) March 31, 2022 Assets (1) Derivatives 9,723 — 9,723 (5) (7,232 ) (891 ) 1,600 Receivables under resale agreements 12,751 — 12,751 (6) (11,437 ) — 1,314 Receivables under securities borrowing transactions 2,339 — 2,339 (7) (2,299 ) — 40 Total 24,813 — 24,813 (20,968 ) (891 ) 2,954 Liabilities (1) Derivatives 9,770 — 9,770 (5) (6,716 ) (1,329 ) 1,725 Payables under repurchase agreements 20,070 — 20,070 (6) (19,366 ) — 704 Payables under securities lending transactions 1,361 — 1,361 (7) (1,164 ) — 197 Total 31,201 — 31,201 (27,246 ) (1,329 ) 2,626 September 30, 2022 Assets (1) Derivatives 18,030 — 18,030 (5) (13,751 ) (1,525 ) 2,754 Receivables under resale agreements 14,872 — 14,872 (6) (13,302 ) — 1,570 Receivables under securities borrowing transactions 2,355 — 2,355 (7) (2,309 ) — 46 Total 35,257 — 35,257 (29,362 ) (1,525 ) 4,370 Liabilities (1) Derivatives 18,294 — 18,294 (5) (12,900 ) (1,924 ) 3,470 Payables under repurchase agreements 23,767 — 23,767 (6) (22,411 ) — 1,356 Payables under securities lending transactions 1,491 — 1,491 (7) (1,225 ) — 266 Total 43,552 — 43,552 (36,536 ) (1,924 ) 5,092 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 ¥9,326 billion and ¥9,235 billion, respectively, at March 31, 2022, and ¥17,032 billion and ¥17,317 billion, respectively, at September 30, 2022. (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 ¥11,537 billion and ¥19,505 billion, respectively, at March 31, 2022, and ¥13,470 billion and ¥22,882 billion, respectively, at September 30, 2022. (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 ¥2,339 billion and ¥1,172 billion, respectively, at March 31, 2022, and ¥2,355 billion and ¥1,229 billion, respectively, at September 30, 2022.

Repurchase agreements and secur

Repurchase agreements and securities lending transactions accounted for as secured borrowings	6 Months Ended
	Sep. 30, 2022
Repurchase agreements and securities lending transactions accounted for as secured borrowings	19. 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, 2022 and September 30, 2022: Overnight and continuous Up to 30 days 31-90 days Greater than 90 days Total (in billions of yen) March 31, 2022 Repurchase agreements 7,011 10,621 1,340 1,098 20,070 Securities lending transactions 1,098 74 — 189 1,361 Total 8,109 10,695 1,340 1,287 21,431 September 30, 2022 Repurchase agreements 3,016 13,156 5,782 1,813 23,767 Securities lending transactions 993 225 11 262 1,491 Total 4,009 13,381 5,793 2,075 25,258 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, 2022 and September 30, 2022: Repurchase agreements Securities lending transactions (in billions of yen) March 31, 2022 Japanese government bonds and Japanese local government bonds 1,714 217 Foreign government bonds and foreign agency mortgage-backed securities 17,445 90 Commercial paper and corporate bonds 271 52 Equity securities 609 989 Other 31 13 Total 20,070 1,361 September 30, 2022 Japanese government bonds and Japanese local government bonds 2,759 210 Foreign government bonds and foreign agency mortgage-backed securities 19,019 236 Commercial paper and corporate bonds 336 64 Equity securities 1,441 969 Other 212 12 Total 23,767 1,491 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. The amounts or composition of assets pledged as collateral for borrowings and for other purposes have not changed significantly since March 31, 2022. See Note 8 “Pledged assets and collateral” to the consolidated financial statements in the MHFG Group’s annual report on Form 20-F

Business segment information

Business segment information	6 Months Ended
	Sep. 30, 2022
Business segment information	20. Business segment information The MHFG Group consists of the following five in-house The services that each in-house company is in charge of are as follows. Retail & Business Banking Company This company provides financial services for individual customers, small and medium-sized enterprises and middle market firms in Japan. Corporate & Institutional Company This company provides financial services for large corporations, financial institutions and public corporations in Japan. Global Corporate Company This company provides financial services for Japanese overseas affiliated corporate customers and non-Japanese corporate customers. Global Markets Company This company invests in financial products with market risk, such as interest rate risk, equity risk, and credit risk. Asset Management Company 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 MHFG (Consolidated) Six months ended September 30, 2021 (1) Retail & Business Banking Company Corporate & Institutional Company Global Corporate Company Global Markets Company Asset Management Company Others (6) Total (in billions of yen) Gross profits + Net gains (losses) related to ETFs and others (2) 346.3 231.5 286.6 258.3 29.0 (21.1 ) 1,130.6 General and administrative expenses (3) 312.8 100.6 142.1 111.0 16.2 (1.8 ) 680.9 Equity in earnings (losses) of equity method investees—net 5.5 2.3 8.9 — 0.9 (1.1 ) 16.5 Amortization of goodwill and others 1.1 — 0.2 0.4 3.6 0.5 5.8 Net business profits (losses) (4) 37.9 133.2 153.2 146.9 10.1 (20.9 ) 460.4 Fixed assets (5) 539.3 181.5 167.2 96.1 — 738.2 1,722.3 MHFG (Consolidated) Six months ended September 30, 2022 (1) Retail & Business Banking Company Corporate & Institutional Company Global Corporate Company Global Markets Company Asset Management Company Others (6) Total (in billions of yen) Gross profits + Net gains (losses) related to ETFs and others (2) 325.7 233.4 317.1 232.5 27.8 26.0 1,162.5 General and administrative expenses (3) 302.2 96.9 152.2 126.1 17.1 27.4 721.9 Equity in earnings (losses) of equity method investees—net (0.9 ) 3.6 11.6 — 0.2 — 14.5 Amortization of goodwill and others 1.0 — 0.2 0.4 3.5 0.5 5.6 Net business profits (losses) (4) 21.6 140.1 176.3 106.0 7.4 (1.9 ) 449.5 Fixed assets (5) 505.9 151.5 167.8 85.8 — 815.0 1,726.0 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 (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 • 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 six months ended September 30, 2021 and 2022 presented above to income (loss) before income tax expense (benefit) shown on the consolidated statements of income and a reconciliation of “Fixed assets” at September 30, 2021 and 2022 to the total amount of Premises and equipment-net, right-of-use Six months ended September 30, 2021 2022 (in billions of yen) Net business profits (losses) + Net gains (losses) related to ETFs and others 460.4 449.5 Adjustment to reconcile management reporting to Japanese GAAP: General and administrative expenses: non-allocated 19.2 21.1 Expenses related to portfolio problems (including reversal of (provision for) general reserve for losses on loans) (59.9 ) (55.4 ) Gains on reversal of reserves for possible losses on loans, and others 10.2 4.9 Net gains (losses) related to stocks—Net gains (losses) related to ETFs and others (6.9 ) 29.7 Net extraordinary gains (losses) 47.3 5.8 Others (23.7 ) (10.5 ) Income before income tax expense under Japanese GAAP 446.6 445.1 Adjustment to reconcile Japanese GAAP to U.S. GAAP: Derivative financial instruments and hedging activities (47.9 ) 1.8 Investments 13.8 (842.1 ) Loans 2.2 (14.0 ) Allowances for credit losses 5.0 11.2 Premises and equipment (34.9 ) (43.0 ) Land revaluation 1.6 1.4 Business combinations 3.4 (5.1 ) Pension liabilities (63.9 ) (26.3 ) Consolidation of variable interest entities 51.1 (53.6 ) Foreign currency translation 2.4 (37.4 ) Others 3.8 (0.6 ) Income (loss) before income tax expense (benefit) under U.S. GAAP 383.2 (562.6 ) As of September 30, 2021 2022 (in billions of yen) Fixed assets 1,722.3 1,726.0 U.S. GAAP adjustments (Note) 763.6 651.9 Premises and equipment-net, right-of-use 2,485.9 2,377.9 Note: The U.S. GAAP adjustments are primarily comprised of GAAP differences mainly from right-of-use

Basis of presentation (Policies

Basis of presentation (Policies)	6 Months Ended
	Sep. 30, 2022
Basis of presentation	1. 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 20 “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 interim financial reporting period ends on September 30. Certain of MHFG’s subsidiaries have different interim financial reporting periods than September 30. For those subsidiaries with interim financial reporting periods within three months of MHFG’s interim financial reporting period, the effect of intervening events that materially affect the financial position or results of operations through the date of each of the periods presented in the MHFG’s consolidated financial statements have 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. The unaudited interim consolidated financial statements should be read in conjunction with the audited financial statements and related notes included in the MHFG Group’s most recent annual report on Form 20-F Certain financial information that is normally included in annual financial statements prepared in accordance with U.S. GAAP, but is not required for interim reporting purposes, has been condensed or omitted. The financial statements reflect all normal and recurring adjustments that are, in the opinion of management, necessary for a fair presentation of the results for the interim periods.
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 deferred tax assets, valuation of derivative financial instruments, valuation of investments, valuation of certain long-term debt where the fair value option has been elected, valuation of pension and other employee benefits, and impairment of long-lived assets. During times of pandemics, such as COVID-19,
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 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 in each reporting period. 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 scenario does not reflect a sudden change in economic conditions adequately, adjustments may be made to the scenario. 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 segment, the MHFG Group considers key economic factors such as gross domestic products for Japan and each relevant foreign location, where the portfolio is significant, and the interest rates in Japan when estimating the credit loss. 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 loan and others. For the retail portfolio segment, the Japanese unemployment rate is applied as a key factor. As it pertains to troubled debt restructuring (“TDR”) loans 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 TDRs, discounted at the loan’s initial 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 are affecting 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 COVID-19 In terms of the Russia-Ukraine situation, considering the country risk arising from the sanctions against Russia and the downgrading of their credit rating, as well as the risk of deterioration in the global economy due to inflation caused by soaring energy prices and the acceleration of supply chain disruptions caused by the withdrawal of operations from Russia, the MHFG Group incorporated an estimate 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 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 available-for-sale

Investments (Tables)

Investments (Tables)	6 Months Ended
	Sep. 30, 2022
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) March 31, 2022 Available-for-sale Debt securities: Japanese government bonds 25,191,315 5,794 38,379 25,158,730 Japanese local government bonds 421,557 254 2,165 419,646 U.S. Treasury bonds and federal agency securities 381,653 — 8,444 373,209 Other foreign government bonds 1,338,295 220 2,578 1,335,937 Agency mortgage-backed securities (1) 452,830 1,695 3,985 450,540 Residential mortgage-backed securities 58,246 194 312 58,128 Commercial mortgage-backed securities 848,568 5,437 214 853,791 Japanese corporate bonds and other debt securities 2,222,670 14,212 1,705 2,235,177 Foreign corporate bonds and other debt securities (2) 787,263 2,490 1,021 788,732 Total 31,702,397 30,296 58,803 31,673,890 Held-to-maturity Debt securities: Japanese government bonds 479,980 5,101 — 485,081 Agency mortgage-backed securities (3) 1,039,075 24 58,604 980,495 Total 1,519,055 5,125 58,604 1,465,576 September 30, 2022 Available-for-sale Debt securities: Japanese government bonds 17,134,700 6,614 38,011 17,103,303 Japanese local government bonds 500,473 149 3,959 496,663 U .S. Treasury bonds and federal agency securities 448,530 — 13,737 434,793 Other foreign government bonds 1,284,950 97 4,804 1,280,243 Agency mortgage-backed securities (1) 500,825 1,112 7,579 494,358 Residential mortgage-backed securities 52,866 97 863 52,100 Commercial mortgage-backed securities 864,060 4,838 321 868,577 Japanese corporate bonds and other debt securities 2,115,489 10,422 4,095 2,121,816 Foreign corporate bonds and other debt securities (2) 891,279 2,193 1,665 891,807 Total 23,793,172 25,522 75,034 23,743,660 Held-to-maturity Debt securities: Japanese government bonds 839,581 3,973 667 842,887 Agency mortgage-backed securities (3) 1,232,887 — 183,109 1,049,778 Total 2,072,468 3,973 183,776 1,892,665 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 ¥450,507 million and ¥33 million, respectively, at March 31, 2022, and ¥494,324 (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 ¥247,762 million at March 31, 2022, and ¥226,762 million at September 30, 2022. (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 ere , and ¥nil at September 30, 2022. (5) Accrued interest receivables are excluded from amortized cost, of which the amount were ¥4,702 million at March 31, 2022, and ¥5,274 million at September 30, 2022 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 13,784,027 1,527,715 1,695,453 127,505 17,134,700 Japanese local government bonds 31,462 254,156 207,348 7,507 500,473 U.S. Treasury bonds and federal agency securities 289,397 159,133 — — 448,530 Other foreign government bonds 1,081,620 200,767 1,283 1,280 1,284,950 Agency mortgage-backed securities — — 1,235 499,590 500,825 Residential mortgage-backed securities — — — 52,866 52,866 Commercial mortgage-backed securities 5,000 518,740 340,320 — 864,060 Japanese corporate bonds and other debt securities 275,168 1,263,577 253,180 323,564 2,115,489 Foreign corporate bonds and other debt securities 485,021 298,537 88,524 19,197 891,279 Total 15,951,695 4,222,625 2,587,343 1,031,509 23,793,172 Held-to-maturity Debt securities: Japanese government bonds 319,987 249,965 269,629 — 839,581 Agency mortgage-backed securities — — — 1,232,887 1,232,887 Total 319,987 249,965 269,629 1,232,887 2,072,468 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 13,785,916 1,523,649 1,674,710 119,028 17,103,303 Japanese local government bonds 31,490 253,676 204,283 7,214 496,663 U.S. Treasury bonds and federal agency securities 282,356 152,437 — — 434,793 Other foreign government bonds 1,079,499 198,182 1,282 1,280 1,280,243 Agency mortgage-backed securities — — 1,229 493,129 494,358 Residential mortgage-backed securities — — — 52,100 52,100 Commercial mortgage-backed securities 4,997 521,126 342,454 — 868,577 Japanese corporate bonds and other debt securities 275,173 1,262,115 252,101 332,427 2,121,816 Foreign corporate bonds and other debt securities 484,357 298,704 88,589 20,157 891,807 Total 15,943,788 4,209,889 2,564,648 1,025,335 23,743,660 Held-to-maturity Debt securities: Japanese government bonds 321,991 251,598 269,298 — 842,887 Agency mortgage-backed securities — — — 1,049,778 1,049,778 Total 321,991 251,598 269,298 1,049,778 1,892,665
Gross Unrealized Losses and Fair Value of Available-for-Sale 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) March 31, 2022 Available-for-sale Debt securities: Japanese government bonds 19,407,878 11,377 1,565,950 27,002 20,973,828 38,379 Japanese local government bonds 229,562 1,277 136,733 888 366,295 2,165 U.S. Treasury bonds and federal agency securities 321,073 7,209 41,555 1,235 362,628 8,444 Other foreign government bonds 729,134 2,178 71,647 400 800,781 2,578 Agency mortgage-backed securities (Note) 183,150 2,326 78,717 1,659 261,867 3,985 Residential mortgage-backed securities 9,221 11 17,193 301 26,414 312 Commercial mortgage-backed securities 58,815 185 13,939 29 72,754 214 Japanese corporate bonds and other debt securities 605,067 1,516 53,020 189 658,087 1,705 Foreign corporate bonds and other debt securities 302,569 692 53,338 329 355,907 1,021 Total 21,846,469 26,771 2,032,092 32,032 23,878,561 58,803 September 30, 2022 Available-for-sale Debt securities: Japanese government bonds 2,725,251 5,019 1,640,200 32,992 4,365,451 38,011 Japanese local government bonds 283,423 2,123 173,980 1,836 457,403 3,959 U.S. Treasury bonds and federal agency securities 373,689 11,682 48,585 2,055 422,274 13,737 Other foreign government bonds 813,981 3,014 208,218 1,790 1,022,199 4,804 Agency mortgage-backed securities (Note) 222,199 3,457 128,252 4,122 350,451 7,579 Residential mortgage-backed securities 25,540 404 15,278 459 40,818 863 Commercial mortgage-backed securities 65,732 168 45,097 153 110,829 321 Japanese corporate bonds and other debt securities 1,470,008 3,741 365,809 354 1,835,817 4,095 Foreign corporate bonds and other debt securities 346,861 1,102 55,116 563 401,977 1,665 Total 6,326,684 30,710 2,680,535 44,324 9,007,219 75,034 Note: Agency mortgage-backed securities presented in this line consist of Japanese agency mortgage-backed securities, of which the fair values were ¥261,867 million at March 31, 2022, and ¥350,451 million at September 30, 2022. 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 See “Consolidated Statements of Cash Flows (Unaudited)” for the proceeds from sales of investments. Six months ended September 30, 2021 2022 (in millions of yen) Gross realized gains 4,687 15,905 Gross realized losses (3,925 ) (9,151 ) Net realized gains (losses) on sales of available-for-sale 762 6,754
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 six months ended September 30, 2021 and 2022: Six months ended September 30, 2021 2022 (in millions of yen) Net gains (losses) recognized during the period on equity securities 135,070 (113,461 ) Less: Net gains (losses) recognized during the period on equity securities sold during the period 29,552 7,246 Unrealized gains (losses) recognized during the reporting period on equity securities still held at the reporting period 105,518 (120,707 )
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. Six months ended September 30, 2021 2022 (in millions of yen) Downward adjustments and impairments 1,704 799 Upward adjustments 14,950 669
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 and September 30, 2022: March 31, 2022 September 30, 2022 (in millions of yen) Carrying amounts at the end of the period 207,407 193,297 Downward adjustments and impairments 6,519 6,887 Upward adjustments 11,623 12,225
Summary of Composition of Other Investments	The following table summarizes the composition of Other investments at March 31, 2022 and September 30, 2022: March 31, 2022 September 30, 2022 (in millions of yen) Equity method investments 519,552 556,778 Investments held by consolidated investment companies and other 62,836 69,370 Total 582,388 626,148

Loans (Tables)

Loans (Tables)	6 Months Ended
	Sep. 30, 2022
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, 2022 and September 30, 2022: March 31, 2022 Term loans by origination year Revolving Loans Total 2021 2020 2019 2018 2017 Prior to 2017 (in millions of yen) Domestic: Corporate: Large companies: Normal obligors 12,236,438 6,640,211 5,049,408 4,535,083 1,678,591 3,378,926 7,155,041 40,673,698 Watch obligors excluding special attention obligors 145,167 69,404 71,937 66,122 40,205 50,499 127,319 570,653 Nonaccrual loans 60,525 100,975 201,375 44,919 135,777 77,602 178,416 799,589 Small and medium-sized Normal obligors 540,315 396,611 376,056 283,061 170,952 494,420 547,726 2,809,141 Watch obligors excluding special attention obligors 44,488 31,196 29,597 31,919 12,231 32,511 25,277 207,219 Nonaccrual loans 17,866 20,110 14,434 10,817 7,081 38,171 32,081 140,560 Retail: Housing Loan: Normal obligors 798,354 544,246 518,662 526,828 543,893 4,752,430 — 7,684,413 Watch obligors excluding special attention obligors 1,512 1,485 1,510 1,939 1,226 40,243 — 47,915 Nonaccrual loans 12,510 3,132 802 1,180 970 30,598 — 49,192 Others: Normal obligors 195,545 277,015 111,702 90,880 60,919 315,375 497,173 1,548,609 Watch obligors excluding special attention obligors 23,586 34,974 10,177 7,995 4,122 6,388 9,491 96,733 Nonaccrual loans 6,932 7,862 3,157 4,253 4,076 22,951 12,602 61,833 Sovereign: Normal obligors 938,534 105,966 89,385 108,664 54,580 351,876 1,864 1,650,869 Watch obligors excluding special attention obligors 3,933 4,205 859 366 113 — — 9,476 Nonaccrual loans — — — — — — — — Banks and other financial institutions: Normal obligors 45,825 23,757 131,932 211,445 3 143,717 125,078 681,757 Watch obligors excluding special attention obligors — — — — — — — — Nonaccrual loans — — — — — — — — Total domestic 15,071,530 8,261,149 6,610,993 5,925,471 2,714,739 9,735,707 8,712,068 57,031,657 Foreign: Corporate (4) Normal obligors 14,087,409 3,571,416 3,236,191 1,392,231 550,082 1,228,924 5,906,045 29,972,298 Watch obligors excluding special attention obligors 316,387 179,555 73,656 55,876 28,325 25,384 122,410 801,593 Nonaccrual loans 35,801 1,622 13,743 17,181 14,743 22,639 9,745 115,474 Retail: Normal obligors 2,403 1,774 1,858 1,013 532 3,089 15 10,684 Watch obligors excluding special attention obligors — — 37 — — 13 — 50 Nonaccrual loans — — — — — — — — Sovereign: Normal obligors 278,373 6,856 33,225 15,194 174,298 3,079 74,923 585,948 Watch obligors excluding special attention obligors — — — — — — — — Nonaccrual loans — — 643 — — — — 643 Banks and other financial institutions: Normal obligors 1,003,709 254,232 150,505 224,571 12,041 709 120,088 1,765,855 Watch obligors excluding special attention obligors 5,544 — — — — — — 5,544 Nonaccrual loans 837 — — — — — — 837 Total foreign 15,730,463 4,015,455 3,509,858 1,706,066 780,021 1,283,837 6,233,226 33,258,926 Total 30,801,993 12,276,604 10,120,851 7,631,537 3,494,760 11,019,544 14,945,294 90,290,583 September 30, 2022 Term loans by origination year Revolving Loans Total 2022 2021 2020 2019 2018 Prior to 2018 (in millions of yen) Domestic: Corporate: Large companies: Normal obligors 7,870,700 7,071,371 5,977,206 4,621,144 3,938,164 4,418,492 7,791,782 41,688,859 Watch obligors excluding special attention obligors 65,982 73,932 63,547 84,634 68,093 74,857 129,011 560,056 Nonaccrual loans 78,466 56,229 71,920 121,977 38,086 133,924 174,556 675,158 Small and medium-sized Normal obligors 310,377 372,070 329,472 310,103 266,522 649,254 505,667 2,743,465 Watch obligors excluding special attention obligors 29,976 24,222 27,907 20,911 21,311 36,433 21,800 182,560 Nonaccrual loans 23,808 14,072 17,798 8,410 8,240 30,351 29,840 132,519 Retail: Housing Loan: Normal obligors 420,132 634,709 506,226 491,602 501,271 5,003,449 — 7,557,389 Watch obligors excluding special attention obligors 406 1,740 1,336 1,111 1,516 35,357 — 41,466 Nonaccrual loans 5,956 4,636 1,956 827 1,015 28,836 — 43,226 Others: Normal obligors 119,310 116,244 254,202 95,347 78,029 335,135 488,953 1,487,220 Watch obligors excluding special attention obligors 14,027 11,090 28,236 7,497 5,246 7,230 8,067 81,393 Nonaccrual loans 8,083 4,745 7,379 2,615 3,411 22,147 10,802 59,182 Sovereign: Normal obligors 950,117 190,195 103,654 94,458 98,581 367,373 — 1,804,378 Watch obligors excluding special attention obligors 4,517 2,538 3,464 321 291 — — 11,131 Nonaccrual loans — — — — — — — — Banks and other financial institutions: Normal obligors 74,820 17,641 23,286 136,043 244,377 143,685 133,705 773,557 Watch obligors excluding special attention obligors — — — — — — — — Nonaccrual loans — — — — — — — — Total domestic 9,976,677 8,595,434 7,417,589 5,997,000 5,274,153 11,286,523 9,294,183 57,841,559 Foreign: Corporate (4) Normal obligors 13,959,808 5,923,058 3,131,452 3,045,313 1,334,469 1,655,488 7,228,807 36,278,395 Watch obligors excluding special attention obligors 227,650 131,936 184,554 74,298 47,282 55,384 120,772 841,876 Nonaccrual loans 5,563 35,354 14,106 51,952 14,308 38,660 9,983 169,926 Retail: Normal obligors 1,221 1,868 1,733 1,850 941 3,278 13 10,904 Watch obligors excluding special attention obligors — — — — — 24 — 24 Nonaccrual loans — — — — — — — — Sovereign: Normal obligors 120,147 260,281 10,594 35,025 11,735 209,034 78,650 725,466 Watch obligors excluding special attention obligors — — — — — — — — Nonaccrual loans — — — 676 — — — 676 Banks and other financial institutions: Normal obligors 1,371,469 439,563 118,506 129,568 29,016 14,155 323,374 2,425,651 Watch obligors excluding special attention obligors 8,912 8,345 8,082 14,475 — — — 39,814 Nonaccrual loans — — — — — — — — Total foreign 15,694,770 6,800,405 3,469,027 3,353,157 1,437,751 1,976,023 7,761,599 40,492,732 Total 25,671,447 15,395,839 10,886,616 9,350,157 6,711,904 13,262,546 17,055,782 98,334,291 Notes: (1) Special attention obligors are watch obligors with debt in TDR or 90 days or more delinquent debt. Loans to such obligors are considered nonaccrual. (2) 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. (3) There were no significant revolving line of credit arrangements that converted to term loans during the fiscal year ended March 31, 2022 and the six months ended September 30, 2022. (4) Corporate of foreign include d we
Impaired Loans Information	The table below presents nonaccrual loans information at March 31, 2022 and September 30, 2022: March 31, 2022 September 30, Amortized cost (1) Nonaccrual loans with an allowance Nonaccrual loans without an allowance Total nonaccrual loans Interest income recognized (2) (in millions of yen) Domestic: Corporate: Large companies 783,305 16,284 799,589 6,787 Small and medium-sized 121,598 18,962 140,560 867 Retail: Housing Loan 26,812 22,380 49,192 477 Others 40,155 21,678 61,833 406 Total domestic 971,870 79,304 1,051,174 8,537 Foreign: Total foreign 110,284 6,670 116,954 843 Total 1,082,154 85,974 1,168,128 9,380 September 30, 2022 September 30, Amortized cost (1) Nonaccrual loans with an allowance Nonaccrual loans without an allowance Total nonaccrual loans Interest income recognized (2) (in millions of yen) Domestic: Corporate: Large companies 657,323 17,835 675,158 10,009 Small and medium-sized companies 114,001 18,518 132,519 803 Retail: Housing Loan 23,491 19,735 43,226 399 Others 38,446 20,736 59,182 377 Total domestic 833,261 76,824 910,085 11,588 Foreign: Total foreign 162,601 8,001 170,602 1,572 Total 995,862 84,825 1,080,687 13,160 Notes: (1) Amounts represent the outstanding balances of nonaccrual loans. The MHFG Group’s policy for placing loans in nonaccrual status corresponds to 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 following table presents modified loans that were determined to be TDRs during the six months ended September 30, 2021 and 2022: Loan forgiveness or debt to equity swaps Interest rate reduction and/or postponement of principal and/or interest Recorded investment (1) Charge-offs (in millions of yen) September 30, 2021 Domestic: Corporate: Large companies 5,849 22,757 375,248 Small and medium-sized — — 60,856 Retail: Housing Loan — — 4,996 Others — — 10,288 Total domestic 5,849 22,757 451,388 Foreign: Total foreign — — 21,206 Total 5,849 22,757 472,594 September 30, 2022 Domestic: Corporate: Large companies — 140,371 256,773 Small and medium-sized — — 55,424 Retail: Housing Loan — — 3,257 Others — — 9,557 Total domestic — 140,371 325,011 Foreign: Total foreign — — 20,779 Total — 140,371 345,790 Notes: (1) Amounts represent the book values of loans immediately after the restructurings. (2) 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 six months ended September 30, 2021 and 2022 with respect to the loans modified as TDRs within the previous twelve months: Recorded investment September 30, 2021 September 30, 2022 (in millions of yen) Domestic: Corporate: Large companies 1,148 91,049 Small and medium-sized 2,157 626 Retail: Housing Loan 579 418 Others 515 722 Total domestic 4,399 92,815 Foreign: Total foreign 14,125 — Total 18,524 92,815
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, 2022 and September 30, 2022: 30-59 days past due 60-89 days past due 90 days or more past Total past due Current Total (in millions of yen) March 31, 2022 Domestic: Corporate: Large companies 323 291 27,275 27,889 42,016,051 42,043,940 Small and medium-sized 693 641 10,370 11,704 3,145,216 3,156,920 Retail: Housing Loan 15,181 8,326 16,548 40,055 7,741,465 7,781,520 Others 4,454 1,068 11,009 16,531 1,690,644 1,707,175 Sovereign — — — — 1,660,345 1,660,345 Banks and other financial institutions — — — — 681,757 681,757 Total domestic 20,651 10,326 65,202 96,179 56,935,478 57,031,657 Foreign: Total foreign — — 28,816 28,816 33,230,110 33,258,926 Total 20,651 10,326 94,018 124,995 90,165,588 90,290,583 September 30, 2022 Domestic: Corporate: Large companies 972 — 33,164 34,136 42,889,937 42,924,073 Small and medium-sized 809 — 11,330 12,139 3,046,405 3,058,544 Retail: Housing Loan 14,486 6,026 16,024 36,536 7,605,545 7,642,081 Others 4,582 1,030 11,130 16,742 1,611,053 1,627,795 Sovereign — — — — 1,815,509 1,815,509 Banks and other financial institutions — — — — 773,557 773,557 Total domestic 20,849 7,056 71,648 99,553 57,742,006 57,841,559 Foreign: Total foreign — — 49,946 49,946 40,442,786 40,492,732 Total 20,849 7,056 121,594 149,499 98,184,792 98,334,291 Note: The majority of total foreign consist of corporate.

Allowance for credit losses o_2

Allowance for credit losses on loans (Tables)	6 Months Ended
	Sep. 30, 2022
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 six months ended September 30, 2021 and 2022 are Domestic Corporate Retail Sovereign Banks and Foreign ( 3 Total (in millions of yen) Six months ended September 30, 2021 Balance at beginning of period 481,420 83,171 68 623 85,567 650,849 Provision (credit) for credit losses on loans 54,150 (376 ) 13 (427 ) (5,155 ) 48,205 Charge-offs (1) (25,880 ) (2,446 ) — — (12,570 ) (40,896 ) Recoveries 5,312 916 — — 263 6,491 Net charge-offs (20,568 ) (1,530 ) — — (12,307 ) (34,405 ) Others ( 2 — — — — 579 579 Balance at end of period 515,002 81,265 81 196 68,684 665,228 Six months ended September 30, 2022 Balance at beginning of period 601,506 73,414 62 438 134,397 809,817 Provision (credit) for credit losses on loans 16,206 (1,078 ) (4 ) 230 23,185 38,539 Charge-offs (1) (146,204 ) (3,005 ) — — (14,403 ) (163,612 ) Recoveries 1,309 760 — — 1,939 4,008 Net charge-offs (144,895 ) (2,245 ) — — (12,464 ) (159,604 ) Others ( 2 — — — — 21,994 21,994 Balance at end of period 472,817 70,091 58 668 167,112 710,746 Notes: (1) Charge-offs increased by ¥122,716 million from the six months ended September 30, 2021 to ¥163,612 million for the six months ended September 30, 2022 due mainly to a debt waiver to a domestic corporate borrower. (2) Others includes primarily foreign exchange translation. (3) The majority of total foreign consist of corporate.

Other assets and liabilities (T

Other assets and liabilities (Tables)	6 Months Ended
	Sep. 30, 2022
Details of Other Assets and Liabilities	The following table sets forth the details of other assets and liabilities at March 31, 2022 and September 30, 2022: March 31, 2022 September 30, 2022 (in millions of yen) Other assets: Accounts receivable: Receivables from brokers, dealers and customers for securities transactions 3,049,874 4,134,148 Other 557,842 438,670 Collateral pledged: Collateral pledged for derivative transactions 1,549,483 2,119,911 Margins provided for futures contracts 466,531 189,133 Other 1,006,849 1,086,446 Prepaid pension cost 762,147 747,563 Right-of-use 570,171 552,233 Security deposits 91,766 86,650 Loans held for sale 156,639 279,321 Other 775,940 885,359 Total 8,987,242 10,519,434 Other liabilities: Accounts payable: Payables to brokers, dealers and customers for securities transactions 1,406,965 1,662,194 Other 494,538 461,188 Guaranteed trust principal (Note) 810,776 821,670 Lease liabilities 593,339 574,190 Collateral accepted: Collateral accepted for derivative transactions 1,075,591 1,744,164 Margins accepted for futures contracts 327,883 131,007 Unearned income 113,181 109,425 Other 1,437,949 1,516,457 Total 6,260,222 7,020,295 Note: 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 15 “Variable interest entities and securitizations” for further discussion of the guaranteed principal money trusts.

Preferred and common stock (Tab

Preferred and common stock (Tables)	6 Months Ended
	Sep. 30, 2022
Schedule of Stock by Class	The composition of preferred stock at March 31, 2022 and September 30, 2022 is as follows: Class of stock March 31, 2022 September 30, 2022 Authorized Issued Authorized Issued (number of shares) Class XIV preferred stock 90,000,000 — 90,000,000 — Class XV preferred stock 90,000,000 — 90,000,000 — Class XVI preferred stock 150,000,000 — 150,000,000 —

Accumulated other comprehensi_2

Accumulated other comprehensive income (loss), net of tax (Tables)	6 Months Ended
	Sep. 30, 2022
Changes in Each Component of Accumulated Other Comprehensive Income (Loss), Net of Tax ("AOCI")	Changes in each component of Accumulated other comprehensive income (loss), net of tax (“AOCI”) for the six months ended September 30, 2021 and 2022 are as follows: Six months ended September 30, 2021 2022 (in millions of yen) AOCI, balance at beginning of period 318,114 440,112 Net unrealized gains (losses) on available-for-sale Balance at beginning of period (8,173 ) (25,046 ) Unrealized holding gains (losses) during period 6,034 (4,329 ) Less: reclassification adjustments for losses (gains) included in net income (525 ) (4,741 ) Change during period 5,509 (9,070 ) Balance at end of period (2,664 ) (34,116 ) Foreign currency translation adjustments: Balance at beginning of period (86,873 ) 94,104 Foreign currency translation adjustments during period 52,231 269,154 Less: reclassification adjustments for losses (gains) included in net income — — Change during period 52,231 269,154 Balance at end of period (34,642 ) 363,258 Defined benefit plan adjustments: Balance at beginning of period 397,153 355,355 Unrealized gains (losses) during period (5,107 ) 4,390 Less: reclassification adjustments for losses (gains) included in net income (9,187 ) (9,183 ) Change during period (14,294 ) (4,793 ) Balance at end of period 382,859 350,562 Own credit risk adjustments: Balance at beginning of period 16,007 15,699 Unrealized gains (losses) during period (6,218 ) 2,998 Less: reclassification adjustments for losses (gains) included in net income 443 434 Change during period (5,775 ) 3,432 Balance at end of period 10,232 19,131 Total other comprehensive income (loss), net of tax attributable to MHFG shareholders 37,671 258,723 AOCI, balance at end of period 355,785 698,835
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 six months ended September 30, 2022: Six months ended September 30, 2022 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 into net income: Affected line items in the consolidated statements of Net unrealized gains (losses) on available-for- 6,759 (2,018 ) 4,741 — 4,741 Investment gains (losses)-net Defined benefit plan adjustments 13,114 (3,940 ) 9,174 9 9,183 Salaries and employee Own credit risk adjustments (626 ) 192 (434 ) — (434 ) Other noninterest income Total 19,247 (5,766 ) 13,481 9 13,490 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) (loss),

Regulatory matters (Tables)

Regulatory matters (Tables)	6 Months Ended
	Sep. 30, 2022
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, 2022 and September 30, 2022 calculated in accordance with Japanese GAAP and the guidelines established by the Financial Services Agency are set forth in the following table: March 31, 2022 September 30, 2022 Amount Ratio Amount Ratio (in billions of yen, except percentages) Consolidated: MHFG: Common Equity Tier 1 capital: Required (1) 5,184 8.01 5,714 8.01 Actual 8,067 12.46 8,097 11.35 Tier 1 capital: Required (1) 6,155 9.51 6,784 9.51 Actual 9,713 15.00 9,733 13.64 Total risk-based capital: Required (1) 7,450 11.51 8,210 11.51 Actual 11,351 17.53 11,216 15.72 Leverage Ratio (2) Required 6,389 3.00 6,925 3.00 Actual 9,713 4.56 9,733 4.21 MHBK: Common Equity Tier 1 capital: Required 2,683 4.50 2,981 4.50 Actual 6,968 11.68 7,082 10.68 Tier 1 capital: Required 3,578 6.00 3,975 6.00 Actual 8,604 14.42 8,714 13.15 Total risk-based capital: Required 4,771 8.00 5,300 8.00 Actual 10,150 17.02 10,110 15.26 Leverage Ratio (2) Required 5,971 3.00 6,509 3.00 Actual 8,604 4.32 8,714 4.01 MHTB: Common Equity Tier 1 capital: Required 79 4.50 76 4.50 Actual 442 25.18 453 26.62 Tier 1 capital: Required 105 6.00 102 6.00 Actual 442 25.18 453 26.62 Total risk-based capital: Required 140 8.00 136 8.00 Actual 442 25.18 453 26.62 Leverage Ratio (2) Required 130 3.00 128 3.00 Actual 442 10.20 453 10.56 March 31, 2022 September 30, 2022 Amount Ratio Amount Ratio (in billions of yen, except percentages) Non-consolidated: MHBK: Common Equity Tier 1 capital: Required 2,528 4.50 2,783 4.50 Actual 6,293 11.20 6,066 9.80 Tier 1 capital: Required 3,370 6.00 3,710 6.00 Actual 7,919 14.09 7,689 12.43 Total risk-based capital: Required 4,494 8.00 4,947 8.00 Actual 9,483 16.88 9,097 14.70 Leverage Ratio (2) Required 5,570 3.00 6,048 3.00 Actual 7,919 4.26 7,689 3.81 MHTB: Common Equity Tier 1 capital: Required 78 4.50 76 4.50 Actual 425 24.40 436 25.68 Tier 1 capital: Required 104 6.00 101 6.00 Actual 425 24.40 436 25.68 Total risk-based capital: Required 139 8.00 135 8.00 Actual 425 24.40 436 25.69 Leverage Ratio (2) Required 126 3.00 124 3.00 Actual 425 10.09 436 10.47 Notes: (1) The required ratios disclosed above, at March 31, 2022 and September 30, 2022, include the capital conservation buffer of 2.5%, the countercyclical capital buffer of 0.01%, and the additional loss absorbency requirements for global systemically important banks (“G-SIBs”) (“D-SIBs”) (2) The required and actual amounts disclosed above at March 31, 2022 and September 30, 2022 exclude amounts of deposits to the Bank of Japan.

Earnings per common share (Tabl

Earnings per common share (Tables)	6 Months Ended
	Sep. 30, 2022
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 six months ended September 30, 2021 and 2022: Six months ended 2021 2022 (in millions of yen) Net income (loss): Net income (loss) attributable to MHFG common shareholders 312,657 (378,877 ) Effect of dilutive securities — — Net income (loss) attributable to common shareholders after assumed conversions 312,657 (378,877 ) Six months ended September 30, 2021 2022 (thousands of shares) Shares: Weighted average common shares outstanding 2,536,902 2,536,315 Effect of dilutive securities: Stock options and the common shares of MHFG under the stock compensation programs (Note) 119 — Weighted average common shares after assumed conversions 2,537,021 2,536,315 Six months ended September 30, 2021 2022 (in yen) Earnings per common share: Basic net income (loss) per common share 123.24 (149.38 ) Diluted net income (loss) per common share (Note) 123.24 (149.38 ) Note: For the six months ended September 30, 2022, 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 six months ended September 30, 2022, 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)	6 Months Ended
	Sep. 30, 2022
Components of Income Tax Expense (Benefit)	The following table presents the components of Income tax expense (benefit) for the six months ended September 30, 2021 and 2022: Six months ended 2021 2022 (in millions of yen) Current tax expense 67,822 67,244 Deferred tax expense (benefit) (28,200 ) (239,149 ) Total income tax expense (benefit) 39,622 (171,905 )
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 six months ended September 30, 2021 and 2022. The detailed amounts recorded directly in Equity are as follows: Six months ended 2021 2022 (in millions of yen) Net unrealized gains (losses) on available-for-sale Unrealized gains (losses) 926 (3,413 ) Less: reclassification adjustments (213 ) (2,018 ) Total 713 (5,431 ) Defined benefit plan adjustments: Unrealized gains (losses) (2,144 ) 1,381 Less: reclassification adjustments (3,875 ) (3,940 ) Total (6,019 ) (2,559 ) Own credit risk adjustments: Unrealized gains (losses) (2,638 ) 1,368 Less: reclassification adjustments 219 192 Total (2,419 ) 1,560 Total tax effect before allocation to noncontrolling interests (7,725 ) (6,430 )

Pension and other employee be_2

Pension and other employee benefit plans (Tables)	6 Months Ended
	Sep. 30, 2022
Components of Net Periodic Benefit Cost of Severance Indemnities and Pension Plans	The following table summarizes the components of net periodic benefit cost of the severance indemnities and pension plans of the MHFG Group for the six months ended September 30, 2021 and 2022: Six months ended September 30, 2021 2022 (in millions of yen) Service cost-benefits earned during the period 16,365 14,559 Interest costs on projected benefit obligations 2,700 3,626 Expected return on plan assets (18,478 ) (18,050 ) Amortization of prior service cost (benefits) (2,410 ) (2,410 ) Amortization of net actuarial loss (gain) (10,263 ) (9,741 ) Special termination benefits 4,154 3,831 Net periodic benefit cost (7,932 ) (8,185 )

Derivative financial instrume_2

Derivative financial instruments (Tables)	6 Months Ended
	Sep. 30, 2022
Summary of Notional and Fair Value Amounts of Derivative Instruments Outstanding	The following table summarizes the notional and fair value amounts of derivative instruments outstanding as of March 31, 2022 and September 30, 2022. 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) March 31, 2022 Notional amount (1) Designated as hedges Not designated as hedges Designated as hedges Not designated as hedges (in billions of yen) Interest rate contracts 1,395,950 — 4,624 — 4,716 Foreign exchange contracts 217,462 — 4,436 — 4,472 Equity-related contracts 9,887 — 426 — 345 Credit-related contracts 11,857 — 118 — 121 Other contracts 681 — 119 — 116 Total 1,635,837 — 9,723 — 9,770 Fair value Derivative receivables (2) Derivative payables (2) September 30, 2022 Notional amount (1) Designated as hedges Not designated as hedges Designated as hedges Not designated as hedges (in billions of yen) Interest rate contracts 1,627,102 — 8,916 — 9,229 Foreign exchange contracts 260,472 — 8,571 — 8,665 Equity-related contracts 7,735 — 285 — 214 Credit-related contracts 21,379 — 166 — 94 Other contracts 1,116 — 92 — 92 Total 1,917,804 — 18,030 — 18,294 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, 2022 and September 30, 2022: March 31, 2022 September 30, 2022 Notional amount Fair value Notional amount Fair value (in billions of yen) Credit protection written: Investment grade 3,045 38 4,370 — Non-investment 2,122 54 5,496 (41 Total 5,167 92 9,866 (41 Credit protection purchased 6,690 (95 ) 11,513 113 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, 2022 and September 30, 2022: Maximum payout/Notional amount March 31, 2022 September 30, 2022 (in billions of yen) One year or less 245 242 After one year through five years 4,785 9,239 After five years 137 385 Total 5,167 9,866 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.
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 six months ended September 30, 2021 and 2022: Gains (losses) recorded in income for six months ended September 30, 2021 2022 (in millions of yen) Interest rate contracts 20,602 (179,783 ) Foreign exchange contracts 7,407 251,060 Equity-related contracts 33,504 482,233 Credit-related contracts (Note) (15,599 ) 42,152 Other contracts 6,875 61,001 Total 52,789 656,663 Note: Amounts include the net gains (losses) of ¥(395) million and ¥172 million on the credit derivatives economically managing the credit risk of loans during the six months ended September 30, 2021 and 2022, respectively.
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, 2022 and September 30, 2022: March 31, 2022 September 30, 2022 (in billions of yen) Aggregate fair value of derivative instruments with credit-risk-related contingent features in net liability positions 1,149 1,866 Collateral provided to counterparties in the normal course of business 1,164 1,743 Amount required to be posted as collateral or settled immediately if credit-risk-related contingent features were triggered — 123 Note: There was no amount that the Group would be required to post as collateral or settle immediately on March 31, 2022.

Commitments and contingencies (

Commitments and contingencies (Tables)	6 Months Ended
	Sep. 30, 2022
Summary of Maximum Potential Amount of Future Payments under Guarantees	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. March 31, 2022 September 30, 2022 (in billions of yen) Performance guarantees 3,254 3,612 Guarantees on loans 419 409 Guarantees on securities 75 89 Other guarantees 2,899 3,683 Guarantees for the repayment of trust principal 22 19 Liabilities of trust accounts 478 529 Derivative financial instruments 36,484 44,900
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, 2022 and September 30, 2022: March 31, 2022 September 30, 2022 (in billions of yen) Commitments to extend credit (Note) 92,203 99,960 Commercial letters of credit 1,422 1,601 Total 93,625 101,561 Note: Commitments to extend credit include commitments to invest in securities.
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, 2022 and September 30, 2022: March 31, 2022 September 30, 2022 (in billions of yen) Investment grade 5,336 6,228 Non-investment grade 1,311 1,565 Total 6,647 7,793 Note: Investment grade in the internal rating scale generally corresponds to BBB-

Variable interest entities an_2

Variable interest entities and securitizations (Tables)	6 Months Ended
	Sep. 30, 2022
Schedule of Variable Interest Entities	The table below shows the consolidated assets of the 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, 2022 and September 30, 2022: Consolidated VIEs Significant March 31, 2022 Consolidated assets Total assets Maximum (in billions of yen) Asset-backed commercial paper/loan programs 2,709 — — Asset-backed securitizations 1,363 190 90 Investments in securitization products 388 — — Investment funds 1,816 3,392 719 Trust arrangements and other 5,299 — — Total 11,575 3,582 809 Consolidated VIEs Significant unconsolidated VIEs September 30, 2022 Consolidated assets Total assets Maximum exposure to (in billions of yen) Asset-backed commercial paper/loan programs 2,991 — — Asset-backed securitizations 1,653 199 121 Investments in securitization products 387 — — Investment funds 2,060 2,952 688 Trust arrangements and other 5,084 — — Total 12,175 3,151 809
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, 2022 and September 30, 2022: Assets on the MHFG Group’s balance sheets related to unconsolidated VIEs: March 31, 2022 September 30, 2022 (in billions of yen) Trading account assets 143 152 Investments 430 373 Loans 92 115 Total 665 640 Liabilities on the MHFG Group’s balance sheets and maximum exposure to loss related to March 31, 2022 September 30, 2022 (in billions of yen) Payables under securities lending transactions 54 59 Trading account liabilities 2 2 Total 56 61 Maximum exposure to loss (Note) 809 809 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)	6 Months Ended
	Sep. 30, 2022
Summary of Noninterest Income	Details of Noninterest income for the six months ended September 30, 2021 and 2022 are as follows: Six months ended September 30, 2021 2022 (in millions of yen) Fee and commission income: Securities-related business (1) 89,387 74,804 Deposits-related business (1) 7,569 7,769 Lending-related business (2)(4) 78,053 79,811 Remittance business (1) 54,576 52,410 Asset management business (1) 60,596 55,508 Trust-related business (1) 66,393 57,395 Agency business (1) 18,573 18,399 Guarantee-related business (3) 16,781 20,680 Fees for other customer services (1) 82,988 81,968 Total Fee and commission income 474,916 448,744 Foreign exchange gains (losses)—net (3) 21,708 128,897 Trading account gains (losses)—net (2) 83,255 (851,080 ) Investment gains (losses)—net: Debt securities (3) (317 ) 8,057 Equity securities (3) 135,070 (113,461 ) Equity in earnings (losses) of equity method investees—net (3) 16,541 (5,003 ) Gains on disposal of premises and equipment (3) 1,988 1,811 Other noninterest income (2)(5) 29,234 168,254 Total 762,395 (213,781 ) 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 17 “Fair value” for further details.

Fair value (Tables)

Fair value (Tables)	6 Months Ended
	Sep. 30, 2022
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, 2022 and September 30, 2022, including those for which the MHFG Group has elected the fair value option, are summarized below: March 31, 2022 Level 1 Level 2 Level 3 Assets/ Liabilities measured at fair value (in billions of yen) Assets: Trading securities (1) Japanese government bonds 1,604 11 — 1,615 Japanese local government bonds — 145 — 145 U.S. Treasury bonds and federal agency securities 2,353 711 — 3,064 Other foreign government bonds 907 639 — 1,546 Agency mortgage-backed securities — 3,176 — 3,176 Residential mortgage-backed securities — — 8 8 Certificates of deposit and commercial paper — 640 — 640 Corporate bonds and other (2) 15 2,743 71 2,829 Equity securities 1,381 213 28 1,622 Trading securities measured at net asset value (3) 284 Derivative financial instruments: Interest rate contracts 89 4,513 22 4,624 Foreign exchange contracts — 4,404 32 4,436 Equity-related contracts 77 323 26 426 Credit-related contracts — 116 2 118 Other contracts 49 18 52 119 Available-for-sale Japanese government bonds 24,662 497 — 25,159 Japanese local government bonds — 420 — 420 U.S. Treasury bonds and federal agency securities 373 — — 373 Other foreign government bonds 363 973 — 1,336 Agency mortgage-backed securities — 451 — 451 Residential mortgage-backed securities — 40 18 58 Commercial mortgage-backed securities — 854 — 854 Japanese corporate bonds and other debt securities — 1,920 315 2,235 Foreign corporate bonds and other debt securities — 671 117 788 Equity securities: Equity securities with readily determinable fair values 3,094 61 — 3,155 Equity securities measured at net asset value (3) 210 Other investments 2 — 56 58 Total assets measured at fair value on a recurring basis 34,969 23,539 747 59,749 Liabilities: Trading securities sold, not yet purchased 3,054 2,035 — 5,089 Derivative financial instruments: Interest rate contracts 80 4,636 — 4,716 Foreign exchange contracts — 4,472 — 4,472 Equity-related contracts 122 183 40 345 Credit-related contracts — 120 1 121 Other contracts 28 36 52 116 Long-term debt (4) — 1,962 794 2,756 Total liabilities measured at fair value on a recurring basis 3,284 13,444 887 17,615 September 30, 2022 Level 1 Level 2 Level 3 Assets/ Liabilities measured at fair value (in billions of yen) Assets: Trading securities (1) Japanese government bonds 1,858 11 — 1,869 Japanese local government bonds — 99 — 99 U.S. Treasury bonds and federal agency securities 2,908 1,129 — 4,037 Other foreign government bonds 863 836 — 1,699 Agency mortgage-backed securities — 4,068 — 4,068 Residential mortgage-backed securities — — 7 7 Certificates of deposit and commercial paper — 797 — 797 Corporate bonds and other (2) 83 2,603 71 2,757 Equity securities 1,621 181 26 1,828 Trading securities measured at net asset value (3) 140 Derivative financial instruments: Interest rate contracts 202 8,663 51 8,916 Foreign exchange contracts — 8,529 42 8,571 Equity-related contracts 96 161 28 285 Credit-related contracts — 164 2 166 Other contracts 36 18 38 92 Available-for-sale Japanese government bonds 16,366 737 — 17,103 Japanese local government bonds — 497 — 497 U.S. Treasury bonds and federal agency securities 435 — — 435 Other foreign government bonds 279 1,001 — 1,280 Agency mortgage-backed securities — 494 — 494 Residential mortgage-backed securities — 37 15 52 Commercial mortgage-backed securities — 869 — 869 Japanese corporate bonds and other debt securities — 1,992 130 2,122 Foreign corporate bonds and other debt securities — 731 161 892 Equity securities: Equity securities with readily determinable fair values 2,913 55 — 2,968 Equity securities measured at net asset value (3) 278 Other investments — — 64 64 Total assets measured at fair value on a recurring basis 27,660 33,672 635 62,385 Liabilities: Trading securities sold, not yet purchased 2,602 3,333 — 5,935 Derivative financial instruments: Interest rate contracts 185 9,043 1 9,229 Foreign exchange contracts — 8,662 3 8,665 Equity-related contracts 69 95 50 214 Credit-related contracts — 90 4 94 Other contracts 28 26 38 92 Long-term debt (4) — 1,930 806 2,736 Total liabilities measured at fair value on a recurring basis 2,884 23,179 902 26,965 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, 2022 and September 30, 2022 were ¥68 billion and ¥61 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 basis using Six months ended September 30, 2021 April 1, 2021 Gains (losses) in Earnings Gains (losses) in OCI Transfers into Level 3 Transfers out of Level 3 Purchases Sales Issuances Settle- ments September 30, 2021 Change in unrealized gains (losses) still held (6) (in billions of yen) Assets: Trading securities: Residential mortgage-backed securities 9 — (2) — — — — — — (1 ) 8 — Corporate bonds and other 1,033 4 (2) — — (1 ) 232 (144 ) — (298 ) 826 5 Equity securities 29 1 (2) — — — — — — — 30 1 Derivative financial instruments, net (1) Interest rate contracts 8 (5 ) (2) — — — — — — 2 5 (5 ) Foreign exchange contracts 23 (1 ) (2) — — — — — — — 22 (2 ) Equity-related contracts (21 ) (14 ) (2) — — — — — — (4 ) (39 ) (22 ) Credit-related contracts 2 (1 ) (2) — (1 ) — — — — 1 1 1 Other contracts — 1 (2) — — — — — — — 1 — Available-for-sale Residential mortgage-backed securities 23 — (3) — (4) — — — — — (3 ) 20 — Commercial mortgage-backed securities 716 — (3) — (4) — — 63 (6 ) — (7 ) 766 — Japanese corporate bonds and other debt 365 2 (3) — (4) — — 8 — — (28 ) 347 2 Foreign corporate bonds and other debt securities 132 — (3) (3 ) (4) — — 19 — — (31 ) 117 — Other investments 53 (1 ) (3) — — — 34 (1 ) — (32 ) 53 (2 ) Liabilities: Trading securities sold, not yet purchased — — (2) — — — (1 ) 1 — — — — Long-term debt 713 6 (5) (5 ) (4) 1 (1 ) — — 256 (216 ) 752 9 Six months ended September 30, 2022 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 September 30, 2022 Change in unrealized gains (losses) still held (6) (in billions of yen) Assets: Trading securities: Residential mortgage-backed securities 8 — (2) — — — — — — (1 ) 7 — Corporate bonds and other 71 6 (2) — 8 (1 ) 65 (29 ) — (49 ) 71 1 Equity securities 28 1 (2) — — — — — — (3 ) 26 (1 ) Derivative financial instruments, net (1) : Interest rate contracts 22 24 (2) — — — — — — 4 50 (27 ) Foreign exchange contracts 32 7 (2) — — — — — — — 39 4 Equity-related contracts (14 ) (12 ) (2) — — — — — — 4 (22 ) (129 ) Credit-related contracts 1 (2 ) (2) — — — — — — (1 ) (2 ) (6 ) Other contracts — — (2) — — — — — — — — — Available-for-sale Residential mortgage-backed securities 18 — (3) — (4) — — — — — (3 ) 15 — Commercial mortgage-backed securities — — (3) — (4) — — — — — — — — Japanese corporate bonds and other debt 315 — (3) — (4) — — 3 — — (188 ) 130 5 Foreign corporate bonds and other debt 117 — (3) 1 (4) — (9 ) 54 — — (2 ) 161 — Other investments 56 3 (3) — — — 36 — — (31 ) 64 — Liabilities: Trading securities sold, not yet purchased — — (2) — — — — — — — — — Long-term debt 794 96 (5) 6 (4) 1 — — — 201 (88 ) 806 109 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, (losses)-net (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 OCI 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 September 30, 2021 and 2022. The amounts of unrealized gains (losses) in OCI are related to Available-for-sale billion and ¥(5) billion, respectively, at September 30, 2021, and ¥5 billion and ¥ 6
Quantitative Information about Significant Unobservable Inputs Related to Material Classes of Level 3 Assets and Liabilities	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, 2022 and September 30, 2022: March 31, 2022 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 26 Discounted cash flow Prepayment rate Default rate Recovery rate Discount margin 0% - 18% 0% - 0% 100% - 100% 30bps - 167bps 6% 0% 100% 53bps Corporate bonds and other debt securities 503 Discounted cash flow Prepayment rate (1) Default rate (1) Recovery rate (1) Discount margin (1) Discount margin (2) 6% - 24% 0% - 60% 10% - 40% 35bps - 103bps 4bps - 447bps 24% 1% 39% 47bps 340bps Derivative financial instruments, net: Interest rate contracts 22 Internal valuation model (3) IR - IR correlation 23% - 100% 75% Foreign exchange contracts 32 Internal valuation model (3) FX - IR correlation FX - FX correlation 11% - 52% 41% - 65% 31% 53% Equity-related contracts (14 ) Internal valuation model (3) Equity - IR correlation Equity correlation Equity volatility 25% - 25% 3% - 100% 13% - 121% 25% 90% 47% Credit-related contracts 1 Internal valuation model (3) Default rate Credit correlation 0% - 8% 43% - 100% 1% 66% Other contracts — Internal valuation model (3) Commodity volatility 0% - 89% 55% Long-term debt 794 Internal valuation model (3) IR - IR correlation FX - IR correlation FX - FX correlation Equity - IR correlation Equity - FX correlation Equity correlation Equity volatility Default rate Credit correlation 23% - 100% 11% - 52% 41% - 65% 25% - 25% -17% - 17% 3% - 100% 9% - 121% 0% - 8% 19% - 100% 75% 39% 53% 25% 0% 90% 34% 1% 64% September 30, 2022 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 22 Discounted cash flow Price-based Prepayment rate Default rate Recovery rate Discount margin 0% - 17% 0% - 2% 100% - 100% 30bps - 167bps 5% 0% 100% 51bps Corporate bonds and other debt securities 362 Discounted cash flow Price-based Prepayment rate (1) Default rate (1) Recovery rate (1) Discount margin (1) Discount margin (2) 26% - 26% 0% - 0% 40% - 40% 63bps - 127bps 4bps - 441bps 26% 0% 40% 74bps 26bps Derivative financial instruments, net: Interest rate contracts 50 Internal valuation model (3) IR - IR correlation 23% - 100% 75% Foreign exchange contracts 39 Internal valuation model (3) FX - IR correlation FX - FX correlation 5% - 55% 41% - 65% 38% 53% Equity-related contracts (22 ) Internal valuation model (3) Equity - IR correlation Equity correlation Equity volatility 25% - 25% 3% - 100% 10% - 181% 25% 91% 54% Credit-related contracts (2 ) Internal valuation model (3) Default rate 0% - 13% 2% Other contracts — Internal valuation model (3) Commodity volatility 0% - 65% 49% Long-term debt 806 Internal valuation model (3) IR - IR correlation FX - IR correlation FX - FX correlation Equity - IR correlation Equity - FX correlation Equity correlation Equity volatility Default rate Credit correlation 23% - 100% 5% - 55% 41% - 65% 25% - 25% -17% - 17% 3% - 10% - 181% 0% - 13% 23% - 100% 75% 40% 53% 25% 0% 90% 37% 3% 65% 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. 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, 2022 and September 30, 2022: March 31, 2022 Total Level 1 Level 2 Level 3 Aggregate cost (in billions of yen) Assets: Loans 81 — — 81 128 Loans held-for-sale 76 — 27 49 77 Equity securities (without readily determinable fair values) 4 — 3 1 4 Premises and equipment-net — — — — 13 Other assets — — — — 3 Total assets measured at fair value on a nonrecurring basis 161 — 30 131 225 September 30, 2022 Total Level 1 Level 2 Level 3 Aggregate cost (in billions of yen) Assets: Loans 94 — — 94 166 Loans held-for-sale 177 — 51 126 192 Equity securities (without readily determinable fair values) 1 — 1 — 1 Other investments 132 132 — — 161 Premises and equipment-net — — — — 1 Total assets measured at fair value on a nonrecurring basis 404 132 52 220 521 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, 2022 and September 30, 2022, 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”): March 31, 2022 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 68,366 68,366 50,628 17,738 — Investments 1,519 1,466 485 981 — Loans, net of allowance (Note) 89,264 90,576 — — 90,576 Financial liabilities: Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions 58,054 58,054 — 58,054 — Interest-bearing deposits 121,833 121,807 — 121,807 — Due to trust accounts 390 390 — 390 — Other short-term borrowings 7,567 7,567 — 7,567 — Long-term debt 9,849 9,681 — 8,162 1,519 September 30, 2022 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 74,254 74,254 53,921 20,333 — Investments 2,072 1,893 843 1,050 — Loans, net of allowance (Note) 97,409 98,912 — — 98,912 Financial liabilities: Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions 57,249 57,249 — 57,249 — Interest-bearing deposits 134,533 134,484 — 134,484 — Due to trust accounts 350 350 — 350 — Other short-term borrowings 3,593 3,593 — 3,593 — Long-term debt 10,846 10,198 — 8,632 1,566 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)	6 Months Ended
	Sep. 30, 2022
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, 2022 and September 30, 2022. 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. Amounts not offset on the balance sheet (3) Gross amounts recognized Gross amounts offset on the balance sheet Net amounts presented on the balance sheet (2) Financial instruments (4) Cash collateral Net amounts (in billions of yen) March 31, 2022 Assets (1) Derivatives 9,723 — 9,723 (5) (7,232 ) (891 ) 1,600 Receivables under resale agreements 12,751 — 12,751 (6) (11,437 ) — 1,314 Receivables under securities borrowing transactions 2,339 — 2,339 (7) (2,299 ) — 40 Total 24,813 — 24,813 (20,968 ) (891 ) 2,954 Liabilities (1) Derivatives 9,770 — 9,770 (5) (6,716 ) (1,329 ) 1,725 Payables under repurchase agreements 20,070 — 20,070 (6) (19,366 ) — 704 Payables under securities lending transactions 1,361 — 1,361 (7) (1,164 ) — 197 Total 31,201 — 31,201 (27,246 ) (1,329 ) 2,626 September 30, 2022 Assets (1) Derivatives 18,030 — 18,030 (5) (13,751 ) (1,525 ) 2,754 Receivables under resale agreements 14,872 — 14,872 (6) (13,302 ) — 1,570 Receivables under securities borrowing transactions 2,355 — 2,355 (7) (2,309 ) — 46 Total 35,257 — 35,257 (29,362 ) (1,525 ) 4,370 Liabilities (1) Derivatives 18,294 — 18,294 (5) (12,900 ) (1,924 ) 3,470 Payables under repurchase agreements 23,767 — 23,767 (6) (22,411 ) — 1,356 Payables under securities lending transactions 1,491 — 1,491 (7) (1,225 ) — 266 Total 43,552 — 43,552 (36,536 ) (1,924 ) 5,092 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 ¥9,326 billion and ¥9,235 billion, respectively, at March 31, 2022, and ¥17,032 billion and ¥17,317 billion, respectively, at September 30, 2022. (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 ¥11,537 billion and ¥19,505 billion, respectively, at March 31, 2022, and ¥13,470 billion and ¥22,882 billion, respectively, at September 30, 2022. (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 ¥2,339 billion and ¥1,172 billion, respectively, at March 31, 2022, and ¥2,355 billion and ¥1,229 billion, respectively, at September 30, 2022.

Repurchase agreements and sec_2

Repurchase agreements and securities lending transactions accounted for as secured borrowings (Tables)	6 Months Ended
	Sep. 30, 2022
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, 2022 and September 30, 2022: Overnight and continuous Up to 30 days 31-90 days Greater than 90 days Total (in billions of yen) March 31, 2022 Repurchase agreements 7,011 10,621 1,340 1,098 20,070 Securities lending transactions 1,098 74 — 189 1,361 Total 8,109 10,695 1,340 1,287 21,431 September 30, 2022 Repurchase agreements 3,016 13,156 5,782 1,813 23,767 Securities lending transactions 993 225 11 262 1,491 Total 4,009 13,381 5,793 2,075 25,258
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, 2022 and September 30, 2022: Repurchase agreements Securities lending transactions (in billions of yen) March 31, 2022 Japanese government bonds and Japanese local government bonds 1,714 217 Foreign government bonds and foreign agency mortgage-backed securities 17,445 90 Commercial paper and corporate bonds 271 52 Equity securities 609 989 Other 31 13 Total 20,070 1,361 September 30, 2022 Japanese government bonds and Japanese local government bonds 2,759 210 Foreign government bonds and foreign agency mortgage-backed securities 19,019 236 Commercial paper and corporate bonds 336 64 Equity securities 1,441 969 Other 212 12 Total 23,767 1,491

Business segment information (T

Business segment information (Tables)	6 Months Ended
	Sep. 30, 2022
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 MHFG (Consolidated) Six months ended September 30, 2021 (1) Retail & Business Banking Company Corporate & Institutional Company Global Corporate Company Global Markets Company Asset Management Company Others (6) Total (in billions of yen) Gross profits + Net gains (losses) related to ETFs and others (2) 346.3 231.5 286.6 258.3 29.0 (21.1 ) 1,130.6 General and administrative expenses (3) 312.8 100.6 142.1 111.0 16.2 (1.8 ) 680.9 Equity in earnings (losses) of equity method investees—net 5.5 2.3 8.9 — 0.9 (1.1 ) 16.5 Amortization of goodwill and others 1.1 — 0.2 0.4 3.6 0.5 5.8 Net business profits (losses) (4) 37.9 133.2 153.2 146.9 10.1 (20.9 ) 460.4 Fixed assets (5) 539.3 181.5 167.2 96.1 — 738.2 1,722.3 MHFG (Consolidated) Six months ended September 30, 2022 (1) Retail & Business Banking Company Corporate & Institutional Company Global Corporate Company Global Markets Company Asset Management Company Others (6) Total (in billions of yen) Gross profits + Net gains (losses) related to ETFs and others (2) 325.7 233.4 317.1 232.5 27.8 26.0 1,162.5 General and administrative expenses (3) 302.2 96.9 152.2 126.1 17.1 27.4 721.9 Equity in earnings (losses) of equity method investees—net (0.9 ) 3.6 11.6 — 0.2 — 14.5 Amortization of goodwill and others 1.0 — 0.2 0.4 3.5 0.5 5.6 Net business profits (losses) (4) 21.6 140.1 176.3 106.0 7.4 (1.9 ) 449.5 Fixed assets (5) 505.9 151.5 167.8 85.8 — 815.0 1,726.0 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 (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 • 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 six months ended September 30, 2021 and 2022 presented above to income (loss) before income tax expense (benefit) shown on the consolidated statements of income and a reconciliation of “Fixed assets” at September 30, 2021 and 2022 to the total amount of Premises and equipment-net, right-of-use Six months ended September 30, 2021 2022 (in billions of yen) Net business profits (losses) + Net gains (losses) related to ETFs and others 460.4 449.5 Adjustment to reconcile management reporting to Japanese GAAP: General and administrative expenses: non-allocated 19.2 21.1 Expenses related to portfolio problems (including reversal of (provision for) general reserve for losses on loans) (59.9 ) (55.4 ) Gains on reversal of reserves for possible losses on loans, and others 10.2 4.9 Net gains (losses) related to stocks—Net gains (losses) related to ETFs and others (6.9 ) 29.7 Net extraordinary gains (losses) 47.3 5.8 Others (23.7 ) (10.5 ) Income before income tax expense under Japanese GAAP 446.6 445.1 Adjustment to reconcile Japanese GAAP to U.S. GAAP: Derivative financial instruments and hedging activities (47.9 ) 1.8 Investments 13.8 (842.1 ) Loans 2.2 (14.0 ) Allowances for credit losses 5.0 11.2 Premises and equipment (34.9 ) (43.0 ) Land revaluation 1.6 1.4 Business combinations 3.4 (5.1 ) Pension liabilities (63.9 ) (26.3 ) Consolidation of variable interest entities 51.1 (53.6 ) Foreign currency translation 2.4 (37.4 ) Others 3.8 (0.6 ) Income (loss) before income tax expense (benefit) under U.S. GAAP 383.2 (562.6 )
Reconciliation of Assets from Segment to Consolidated	As of September 30, 2021 2022 (in billions of yen) Fixed assets 1,722.3 1,726.0 U.S. GAAP adjustments (Note) 763.6 651.9 Premises and equipment-net, right-of-use 2,485.9 2,377.9 Note: The U.S. GAAP adjustments are primarily comprised of GAAP differences mainly from right-of-use

Basis of presentation - Additio

Basis of presentation - Additional Information (Detail)	6 Months Ended
	Sep. 30, 2022
Minimum
Disclosure of Accounting Policies [Line Items]
Period in which obligors generally determined to be substantially bankrupt, past due (in months)	6 months

Investments - Amortized Cost, G

Investments - Amortized Cost, Gross Unrealized Gains and Losses, and Fair Value of Available-for-Sale Securities (Detail) - JPY (¥) ¥ in Millions		Sep. 30, 2022	Mar. 31, 2022
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities		¥ 75,034	¥ 58,803
Fair value, available-for-sale securities		23,743,660	31,673,890
Amortized cost, held-to-maturity securities		2,072,468	1,519,055
Total		1,892,665
Debt securities | Japanese government bonds
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities		38,011	38,379
Debt securities | Japanese local government bonds
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities		3,959	2,165
Debt securities | U.S. Treasury bonds and federal agency securities
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities		13,737	8,444
Debt securities | Other foreign government bonds
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities		4,804	2,578
Debt securities | Agency mortgage-backed securities
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities	[1]	7,579	3,985
Debt securities | Residential mortgage-backed securities
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities		863	312
Debt securities | Commercial mortgage-backed securities
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities		321	214
Debt securities | Japanese corporate bonds and other debt securities
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities		4,095	1,705
Debt securities | Foreign corporate bonds and other debt securities
Schedule of Investments [Line Items]
Gross unrealized losses, available-for-sale securities		1,665	1,021
Available-for-sale securities | Debt securities
Schedule of Investments [Line Items]
Amortized cost, net available-for-sale securities	[2],[3]	23,793,172	31,702,397
Gross unrealized gains, available-for-sale securities		25,522	30,296
Gross unrealized losses, available-for-sale securities		75,034	58,803
Fair value, available-for-sale securities		23,743,660	31,673,890
Available-for-sale securities | Debt securities | Japanese government bonds
Schedule of Investments [Line Items]
Amortized cost, net available-for-sale securities	[2],[3]	17,134,700	25,191,315
Gross unrealized gains, available-for-sale securities		6,614	5,794
Gross unrealized losses, available-for-sale securities		38,011	38,379
Fair value, available-for-sale securities		17,103,303	25,158,730
Available-for-sale securities | Debt securities | Japanese local government bonds
Schedule of Investments [Line Items]
Amortized cost, net available-for-sale securities	[2],[3]	500,473	421,557
Gross unrealized gains, available-for-sale securities		149	254
Gross unrealized losses, available-for-sale securities		3,959	2,165
Fair value, available-for-sale securities		496,663	419,646
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]	448,530	381,653
Gross unrealized gains, available-for-sale securities		0	0
Gross unrealized losses, available-for-sale securities		13,737	8,444
Fair value, available-for-sale securities		434,793	373,209
Available-for-sale securities | Debt securities | Other foreign government bonds
Schedule of Investments [Line Items]
Amortized cost, net available-for-sale securities	[2],[3]	1,284,950	1,338,295
Gross unrealized gains, available-for-sale securities		97	220
Gross unrealized losses, available-for-sale securities		4,804	2,578
Fair value, available-for-sale securities		1,280,243	1,335,937
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]	500,825	452,830
Gross unrealized gains, available-for-sale securities	[4]	1,112	1,695
Gross unrealized losses, available-for-sale securities	[4]	7,579	3,985
Fair value, available-for-sale securities	[4]	494,358	450,540
Available-for-sale securities | Debt securities | Residential mortgage-backed securities
Schedule of Investments [Line Items]
Amortized cost, net available-for-sale securities	[2],[3]	52,866	58,246
Gross unrealized gains, available-for-sale securities		97	194
Gross unrealized losses, available-for-sale securities		863	312
Fair value, available-for-sale securities		52,100	58,128
Available-for-sale securities | Debt securities | Commercial mortgage-backed securities
Schedule of Investments [Line Items]
Amortized cost, net available-for-sale securities	[2],[3]	864,060	848,568
Gross unrealized gains, available-for-sale securities		4,838	5,437
Gross unrealized losses, available-for-sale securities		321	214
Fair value, available-for-sale securities		868,577	853,791
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]	2,115,489	2,222,670
Gross unrealized gains, available-for-sale securities		10,422	14,212
Gross unrealized losses, available-for-sale securities		4,095	1,705
Fair value, available-for-sale securities		2,121,816	2,235,177
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]	891,279	787,263
Gross unrealized gains, available-for-sale securities	[5]	2,193	2,490
Gross unrealized losses, available-for-sale securities	[5]	1,665	1,021
Fair value, available-for-sale securities	[5]	891,807	788,732
Held-to-maturity Securities | Debt securities
Schedule of Investments [Line Items]
Amortized cost, held-to-maturity securities	[2],[3]	2,072,468	1,519,055
Gross unrealized gains, held-to-maturity securities		3,973	5,125
Gross unrealized losses, held-to-maturity securities		183,776	58,604
Total		1,892,665	1,465,576
Held-to-maturity Securities | Debt securities | Japanese government bonds
Schedule of Investments [Line Items]
Amortized cost, held-to-maturity securities	[2],[3]	839,581	479,980
Gross unrealized gains, held-to-maturity securities		3,973	5,101
Gross unrealized losses, held-to-maturity securities		667	0
Total		842,887	485,081
Held-to-maturity Securities | Debt securities | Agency mortgage-backed securities
Schedule of Investments [Line Items]
Amortized cost, held-to-maturity securities	[2],[3],[6]	1,232,887	1,039,075
Gross unrealized gains, held-to-maturity securities	[6]	0	24
Gross unrealized losses, held-to-maturity securities	[6]	183,109	58,604
Total	[6]	¥ 1,049,778	¥ 980,495
[1]Agency mortgage-backed securities presented in this line consist of Japanese agency mortgage-backed securities, of which the fair values were ¥261,867 million at March 31, 2022, and ¥350,451 million at September 30, 2022. 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 ¥4,702 million at March 31, 2022, and ¥5,274 million at September 30, 2022 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 was ¥34,326 million at March 31, 2022.[4]Agency mortgage-backed securities presented in this line consist of Japanese and Foreign agency mortgage-backed securities, of which the fair values were ¥450,507 million and ¥33 million, respectively, at March 31, 2022, and ¥494,324 million and ¥34 million, respectively, at September 30, 2022. 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 ¥247,762 million at March 31, 2022, and ¥226,762 million at September 30, 2022.[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 Securities (Parenthetical) (Detail) - JPY (¥) ¥ in Millions	Sep. 30, 2022	Mar. 31, 2022
Schedule of Investments [Line Items]
Fair value, available-for-sale securities	¥ 23,743,660	¥ 31,673,890
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	34,326
Debt securities | Negotiable certificates of deposits, asset- backed securities and collateral loan obligations
Schedule of Investments [Line Items]
Fair value, available-for-sale securities	226,762	247,762
Debt securities | Japanese agency mortgage-backed securities | Agency mortgage-backed securities
Schedule of Investments [Line Items]
Fair value, available-for-sale securities	494,324	450,507
Debt securities | Foreign agency mortgage-backed securities | Agency mortgage-backed securities
Schedule of Investments [Line Items]
Fair value, available-for-sale securities	34	33
Available-for sale and held-to-maturity securities | Accrued income
Schedule of Investments [Line Items]
Accrued interest receivables	¥ 5,274	¥ 4,702

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	Sep. 30, 2022	Mar. 31, 2022
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost	¥ 15,951,695
Due after one year through five years, amortized cost	4,222,625
Due after five years through ten years,amortized cost	2,587,343
Due after ten years, amortized cost	1,031,509
Total	23,793,172
Due in one year or less, amortized cost	319,987
Due after one year through five years, amortized cost	249,965
Due after five years through ten years, amortized cost	269,629
Due after ten years, amortized cost	1,232,887
Amortized cost, held-to-maturity securities	2,072,468	¥ 1,519,055
Due in one year or less, fair value	15,943,788
Due after one year through five years, fair value	4,209,889
Due after five years through ten years, fair value	2,564,648
Due after ten years, fair value	1,025,335
Total	23,743,660
Due in one year or less, fair value	321,991
Due after one year through five years, fair value	251,598
Due after five years through ten years, fair value	269,298
Due after ten years, fair value	1,049,778
Total	1,892,665
Debt securities | Japanese government bonds
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost	13,784,027
Due after one year through five years, amortized cost	1,527,715
Due after five years through ten years,amortized cost	1,695,453
Due after ten years, amortized cost	127,505
Total	17,134,700
Due in one year or less, amortized cost	319,987
Due after one year through five years, amortized cost	249,965
Due after five years through ten years, amortized cost	269,629
Due after ten years, amortized cost	0
Amortized cost, held-to-maturity securities	839,581
Due in one year or less, fair value	13,785,916
Due after one year through five years, fair value	1,523,649
Due after five years through ten years, fair value	1,674,710
Due after ten years, fair value	119,028
Total	17,103,303
Due in one year or less, fair value	321,991
Due after one year through five years, fair value	251,598
Due after five years through ten years, fair value	269,298
Due after ten years, fair value	0
Total	842,887
Debt securities | Japanese local government bonds
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost	31,462
Due after one year through five years, amortized cost	254,156
Due after five years through ten years,amortized cost	207,348
Due after ten years, amortized cost	7,507
Total	500,473
Due in one year or less, fair value	31,490
Due after one year through five years, fair value	253,676
Due after five years through ten years, fair value	204,283
Due after ten years, fair value	7,214
Total	496,663
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	289,397
Due after one year through five years, amortized cost	159,133
Due after five years through ten years,amortized cost	0
Due after ten years, amortized cost	0
Total	448,530
Due in one year or less, fair value	282,356
Due after one year through five years, fair value	152,437
Due after five years through ten years, fair value	0
Due after ten years, fair value	0
Total	434,793
Debt securities | Other foreign government bonds
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost	1,081,620
Due after one year through five years, amortized cost	200,767
Due after five years through ten years,amortized cost	1,283
Due after ten years, amortized cost	1,280
Total	1,284,950
Due in one year or less, fair value	1,079,499
Due after one year through five years, fair value	198,182
Due after five years through ten years, fair value	1,282
Due after ten years, fair value	1,280
Total	1,280,243
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	1,235
Due after ten years, amortized cost	499,590
Total	500,825
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	1,232,887
Amortized cost, held-to-maturity securities	1,232,887
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	1,229
Due after ten years, fair value	493,129
Total	494,358
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	1,049,778
Total	1,049,778
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	52,866
Total	52,866
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	52,100
Total	52,100
Debt securities | Commercial mortgage-backed securities
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost	5,000
Due after one year through five years, amortized cost	518,740
Due after five years through ten years,amortized cost	340,320
Due after ten years, amortized cost	0
Total	864,060
Due in one year or less, fair value	4,997
Due after one year through five years, fair value	521,126
Due after five years through ten years, fair value	342,454
Due after ten years, fair value	0
Total	868,577
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	275,168
Due after one year through five years, amortized cost	1,263,577
Due after five years through ten years,amortized cost	253,180
Due after ten years, amortized cost	323,564
Total	2,115,489
Due in one year or less, fair value	275,173
Due after one year through five years, fair value	1,262,115
Due after five years through ten years, fair value	252,101
Due after ten years, fair value	332,427
Total	2,121,816
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	485,021
Due after one year through five years, amortized cost	298,537
Due after five years through ten years,amortized cost	88,524
Due after ten years, amortized cost	19,197
Total	891,279
Due in one year or less, fair value	484,357
Due after one year through five years, fair value	298,704
Due after five years through ten years, fair value	88,589
Due after ten years, fair value	20,157
Total	¥ 891,807

Investments - Additional Inform

Investments - Additional Information (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Mar. 31, 2022	Mar. 31, 2021
Gain (Loss) on Securities [Line Items]
Equity method Investments, carrying value	¥ 556,778		¥ 519,552
Japanese corporate bonds and other debt securities
Gain (Loss) on Securities [Line Items]
Credit losses on available-for-sale securities	0	¥ 11,000
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	(34,000)	(3,000)
Held-to-maturity Securities | Japanese government bonds
Gain (Loss) on Securities [Line Items]
Credit losses on available-for-sale securities	¥ 0		0
Held-to-maturity Securities | Agency mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Credit losses on available-for-sale securities		¥ 0		¥ 0
Orient Corporation
Gain (Loss) on Securities [Line Items]
Percentage of proportionate share to the total outstanding common stock	49%
Chiba Kogya Bank LTD [Member]
Gain (Loss) on Securities [Line Items]
Percentage of proportionate share to the total outstanding common stock	16.89%
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	18.29%
Custody Bank of Japan Ltd [Member]
Gain (Loss) on Securities [Line Items]
Percentage of proportionate share to the total outstanding common stock	27%
Equity securities (marketable)
Gain (Loss) on Securities [Line Items]
Equity method Investments, carrying value	¥ 268,393		255,336
Equity method Investments, aggregated market values	¥ 452,342		¥ 456,195

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		Sep. 30, 2022	Mar. 31, 2022
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		¥ 6,326,684	¥ 21,846,469
Less than 12 months Gross unrealized losses, available-for-sale securities		30,710	26,771
12 months or more Fair value, available-for-sale securities		2,680,535	2,032,092
12 months or more Gross unrealized losses, available-for-sale securities		44,324	32,032
Total Fair value, available-for-sale securities		9,007,219	23,878,561
Total Gross unrealized losses, available-for-sale securities		75,034	58,803
Debt securities | Japanese government bonds
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		2,725,251	19,407,878
Less than 12 months Gross unrealized losses, available-for-sale securities		5,019	11,377
12 months or more Fair value, available-for-sale securities		1,640,200	1,565,950
12 months or more Gross unrealized losses, available-for-sale securities		32,992	27,002
Total Fair value, available-for-sale securities		4,365,451	20,973,828
Total Gross unrealized losses, available-for-sale securities		38,011	38,379
Debt securities | Japanese local government bonds
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		283,423	229,562
Less than 12 months Gross unrealized losses, available-for-sale securities		2,123	1,277
12 months or more Fair value, available-for-sale securities		173,980	136,733
12 months or more Gross unrealized losses, available-for-sale securities		1,836	888
Total Fair value, available-for-sale securities		457,403	366,295
Total Gross unrealized losses, available-for-sale securities		3,959	2,165
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		373,689	321,073
Less than 12 months Gross unrealized losses, available-for-sale securities		11,682	7,209
12 months or more Fair value, available-for-sale securities		48,585	41,555
12 months or more Gross unrealized losses, available-for-sale securities		2,055	1,235
Total Fair value, available-for-sale securities		422,274	362,628
Total Gross unrealized losses, available-for-sale securities		13,737	8,444
Debt securities | Other foreign government bonds
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		813,981	729,134
Less than 12 months Gross unrealized losses, available-for-sale securities		3,014	2,178
12 months or more Fair value, available-for-sale securities		208,218	71,647
12 months or more Gross unrealized losses, available-for-sale securities		1,790	400
Total Fair value, available-for-sale securities		1,022,199	800,781
Total Gross unrealized losses, available-for-sale securities		4,804	2,578
Debt securities | Agency mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities	[1]	222,199	183,150
Less than 12 months Gross unrealized losses, available-for-sale securities	[1]	3,457	2,326
12 months or more Fair value, available-for-sale securities	[1]	128,252	78,717
12 months or more Gross unrealized losses, available-for-sale securities	[1]	4,122	1,659
Total Fair value, available-for-sale securities	[1]	350,451	261,867
Total Gross unrealized losses, available-for-sale securities	[1]	7,579	3,985
Debt securities | Residential mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		25,540	9,221
Less than 12 months Gross unrealized losses, available-for-sale securities		404	11
12 months or more Fair value, available-for-sale securities		15,278	17,193
12 months or more Gross unrealized losses, available-for-sale securities		459	301
Total Fair value, available-for-sale securities		40,818	26,414
Total Gross unrealized losses, available-for-sale securities		863	312
Debt securities | Commercial mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		65,732	58,815
Less than 12 months Gross unrealized losses, available-for-sale securities		168	185
12 months or more Fair value, available-for-sale securities		45,097	13,939
12 months or more Gross unrealized losses, available-for-sale securities		153	29
Total Fair value, available-for-sale securities		110,829	72,754
Total Gross unrealized losses, available-for-sale securities		321	214
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		1,470,008	605,067
Less than 12 months Gross unrealized losses, available-for-sale securities		3,741	1,516
12 months or more Fair value, available-for-sale securities		365,809	53,020
12 months or more Gross unrealized losses, available-for-sale securities		354	189
Total Fair value, available-for-sale securities		1,835,817	658,087
Total Gross unrealized losses, available-for-sale securities		4,095	1,705
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		346,861	302,569
Less than 12 months Gross unrealized losses, available-for-sale securities		1,102	692
12 months or more Fair value, available-for-sale securities		55,116	53,338
12 months or more Gross unrealized losses, available-for-sale securities		563	329
Total Fair value, available-for-sale securities		401,977	355,907
Total Gross unrealized losses, available-for-sale securities		¥ 1,665	¥ 1,021
[1]Agency mortgage-backed securities presented in this line consist of Japanese agency mortgage-backed securities, of which the fair values were ¥261,867 million at March 31, 2022, and ¥350,451 million at September 30, 2022. 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		Sep. 30, 2022	Mar. 31, 2022
Gain (Loss) on Securities [Line Items]
Fair value, available-for-sale securities		¥ 9,007,219	¥ 23,878,561
Debt securities | Agency mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Fair value, available-for-sale securities	[1]	350,451	261,867
Debt securities | Japanese agency mortgage-backed securities | Agency mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Fair value, available-for-sale securities		¥ 350,451	¥ 261,867
[1]Agency mortgage-backed securities presented in this line consist of Japanese agency mortgage-backed securities, of which the fair values were ¥261,867 million at March 31, 2022, and ¥350,451 million at September 30, 2022. 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	6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Debt Securities, Available-for-sale [Line Items]
Gross realized gains	¥ 15,905	¥ 4,687
Gross realized losses	(9,151)	(3,925)
Net realized gains (losses) on sales of available-for-sale securities	¥ 6,754	¥ 762

Investments - Summary of Detail

Investments - Summary of Details of Net Gains and Losses on Equity Securities (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Gain (Loss) on Securities [Line Items]
Net gains (losses) recognized during the period on equity securities	¥ (113,461)	¥ 135,070
Less: Net gains (losses) recognized during the period on equity securities sold during the period	7,246	29,552
Unrealized gains (losses) recognized during the reporting period on equity securities still held at the reporting period	¥ (120,707)	¥ 105,518

Investments - Summary of Equity

Investments - Summary of Equity Securities Without Readily Determinable Fair Values (Detail) - JPY (¥) ¥ in Millions	Sep. 30, 2022	Mar. 31, 2022
Equity Securities without Readily Determinable Fair Value [Line Items]
Carrying amounts at the end of the period	¥ 193,297	¥ 207,407
Downward adjustments and impairments	6,887	6,519
Upward adjustments	¥ 12,225	¥ 11,623

Investments - Summary of Downwa

Investments - Summary of Downward Adjustments and Impairments and Upward Adjustments (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Equity Securities without Readily Determinable Fair Value [Line Items]
Downward adjustments and impairments	¥ 799	¥ 1,704
Upward adjustments	¥ 669	¥ 14,950

Investments - Summary of Compos

Investments - Summary of Composition of Other Investments (Detail) - JPY (¥) ¥ in Millions	Sep. 30, 2022	Mar. 31, 2022
Schedule of Investments [Line Items]
Equity method investments	¥ 556,778	¥ 519,552
Investments held by consolidated investment companies and other	69,370	62,836
Total	¥ 626,148	¥ 582,388

Loans - Additional Information

Loans - Additional Information (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Mar. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net losses on sales of loans	¥ 4,873	¥ 1,674
Accrued income
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accrued interest receivables	145,845		¥ 80,959
Impaired Financing Receivables with No Related Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans partially charged off	¥ 15,265		¥ 13,046

Loans - Credit Quality Informat

Loans - Credit Quality Information of Loans Based on MHFG Group's Internal Rating System (Detail) - JPY (¥) ¥ in Millions	Sep. 30, 2022	Mar. 31, 2022
Normal obligors | Domestic | Retail | Housing loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	¥ 420,132	¥ 798,354
2021	634,709	544,246
2020	506,226	518,662
2019	491,602	526,828
2018	501,271	543,893
Prior to 2018	5,003,449	4,752,430
Revolving loan	0	0
Total	7,557,389	7,684,413
Normal obligors | Domestic | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	119,310	195,545
2021	116,244	277,015
2020	254,202	111,702
2019	95,347	90,880
2018	78,029	60,919
Prior to 2018	335,135	315,375
Revolving loan	488,953	497,173
Total	1,487,220	1,548,609
Watch obligors | Domestic | Retail | Housing loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	406	1,512
2021	1,740	1,485
2020	1,336	1,510
2019	1,111	1,939
2018	1,516	1,226
Prior to 2018	35,357	40,243
Revolving loan	0	0
Total	41,466	47,915
Watch obligors | Domestic | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	14,027	23,586
2021	11,090	34,974
2020	28,236	10,177
2019	7,497	7,995
2018	5,246	4,122
Prior to 2018	7,230	6,388
Revolving loan	8,067	9,491
Total	81,393	96,733
Nonaccrual loans | Domestic | Retail | Housing loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	5,956	12,510
2021	4,636	3,132
2020	1,956	802
2019	827	1,180
2018	1,015	970
Prior to 2018	28,836	30,598
Revolving loan	0	0
Total	43,226	49,192
Nonaccrual loans | Domestic | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	8,083	6,932
2021	4,745	7,862
2020	7,379	3,157
2019	2,615	4,253
2018	3,411	4,076
Prior to 2018	22,147	22,951
Revolving loan	10,802	12,602
Total	59,182	61,833
Financing Receivables Not Impaired
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	25,671,447	30,801,993
2021	15,395,839	12,276,604
2020	10,886,616	10,120,851
2019	9,350,157	7,631,537
2018	6,711,904	3,494,760
Prior to 2018	13,262,546	11,019,544
Revolving loan	17,055,782	14,945,294
Total	98,334,291	90,290,583
Financing Receivables Not Impaired | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	9,976,677	15,071,530
2021	8,595,434	8,261,149
2020	7,417,589	6,610,993
2019	5,997,000	5,925,471
2018	5,274,153	2,714,739
Prior to 2018	11,286,523	9,735,707
Revolving loan	9,294,183	8,712,068
Total	57,841,559	57,031,657
Financing Receivables Not Impaired | Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	15,694,770	15,730,463
2021	6,800,405	4,015,455
2020	3,469,027	3,509,858
2019	3,353,157	1,706,066
2018	1,437,751	780,021
Prior to 2018	1,976,023	1,283,837
Revolving loan	7,761,599	6,233,226
Total	40,492,732	33,258,926
Financing Receivables Not Impaired | Normal obligors | Domestic | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	950,117	938,534
2021	190,195	105,966
2020	103,654	89,385
2019	94,458	108,664
2018	98,581	54,580
Prior to 2018	367,373	351,876
Revolving loan	0	1,864
Total	1,804,378	1,650,869
Financing Receivables Not Impaired | Normal obligors | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	74,820	45,825
2021	17,641	23,757
2020	23,286	131,932
2019	136,043	211,445
2018	244,377	3
Prior to 2018	143,685	143,717
Revolving loan	133,705	125,078
Total	773,557	681,757
Financing Receivables Not Impaired | Normal obligors | Domestic | Corporate | Large companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	7,870,700	12,236,438
2021	7,071,371	6,640,211
2020	5,977,206	5,049,408
2019	4,621,144	4,535,083
2018	3,938,164	1,678,591
Prior to 2018	4,418,492	3,378,926
Revolving loan	7,791,782	7,155,041
Total	41,688,859	40,673,698
Financing Receivables Not Impaired | Normal obligors | Domestic | Corporate | Small and medium sized companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	310,377	540,315
2021	372,070	396,611
2020	329,472	376,056
2019	310,103	283,061
2018	266,522	170,952
Prior to 2018	649,254	494,420
Revolving loan	505,667	547,726
Total	2,743,465	2,809,141
Financing Receivables Not Impaired | Normal obligors | Foreign | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	120,147	278,373
2021	260,281	6,856
2020	10,594	33,225
2019	35,025	15,194
2018	11,735	174,298
Prior to 2018	209,034	3,079
Revolving loan	78,650	74,923
Total	725,466	585,948
Financing Receivables Not Impaired | Normal obligors | Foreign | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	1,371,469	1,003,709
2021	439,563	254,232
2020	118,506	150,505
2019	129,568	224,571
2018	29,016	12,041
Prior to 2018	14,155	709
Revolving loan	323,374	120,088
Total	2,425,651	1,765,855
Financing Receivables Not Impaired | Normal obligors | Foreign | Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	13,959,808	14,087,409
2021	5,923,058	3,571,416
2020	3,131,452	3,236,191
2019	3,045,313	1,392,231
2018	1,334,469	550,082
Prior to 2018	1,655,488	1,228,924
Revolving loan	7,228,807	5,906,045
Total	36,278,395	29,972,298
Financing Receivables Not Impaired | Normal obligors | Foreign | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	1,221	2,403
2021	1,868	1,774
2020	1,733	1,858
2019	1,850	1,013
2018	941	532
Prior to 2018	3,278	3,089
Revolving loan	13	15
Total	10,904	10,684
Financing Receivables Not Impaired | Watch obligors | Domestic | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	4,517	3,933
2021	2,538	4,205
2020	3,464	859
2019	321	366
2018	291	113
Prior to 2018	0	0
Revolving loan	0	0
Total	11,131	9,476
Financing Receivables Not Impaired | Watch obligors | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	0	0
2021	0	0
2020	0	0
2019	0	0
2018	0	0
Prior to 2018	0	0
Revolving loan	0	0
Total	0	0
Financing Receivables Not Impaired | Watch obligors | Domestic | Corporate | Large companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	65,982	145,167
2021	73,932	69,404
2020	63,547	71,937
2019	84,634	66,122
2018	68,093	40,205
Prior to 2018	74,857	50,499
Revolving loan	129,011	127,319
Total	560,056	570,653
Financing Receivables Not Impaired | Watch obligors | Domestic | Corporate | Small and medium sized companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	29,976	44,488
2021	24,222	31,196
2020	27,907	29,597
2019	20,911	31,919
2018	21,311	12,231
Prior to 2018	36,433	32,511
Revolving loan	21,800	25,277
Total	182,560	207,219
Financing Receivables Not Impaired | Watch obligors | Foreign | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	0	0
2021	0	0
2020	0	0
2019	0	0
2018	0	0
Prior to 2018	0	0
Revolving loan	0	0
Total	0	0
Financing Receivables Not Impaired | Watch obligors | Foreign | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	8,912	5,544
2021	8,345	0
2020	8,082	0
2019	14,475	0
2018	0	0
Prior to 2018	0	0
Revolving loan	0	0
Total	39,814	5,544
Financing Receivables Not Impaired | Watch obligors | Foreign | Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	227,650	316,387
2021	131,936	179,555
2020	184,554	73,656
2019	74,298	55,876
2018	47,282	28,325
Prior to 2018	55,384	25,384
Revolving loan	120,772	122,410
Total	841,876	801,593
Financing Receivables Not Impaired | Watch obligors | Foreign | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	0	0
2021	0	0
2020	0	37
2019	0	0
2018	0	0
Prior to 2018	24	13
Revolving loan	0	0
Total	24	50
Financing Receivables Not Impaired | Nonaccrual loans | Domestic | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	0	0
2021	0	0
2020	0	0
2019	0	0
2018	0	0
Prior to 2018	0	0
Revolving loan	0	0
Total	0	0
Financing Receivables Not Impaired | Nonaccrual loans | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	0	0
2021	0	0
2020	0	0
2019	0	0
2018	0	0
Prior to 2018	0	0
Revolving loan	0	0
Total	0	0
Financing Receivables Not Impaired | Nonaccrual loans | Domestic | Corporate | Large companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	78,466	60,525
2021	56,229	100,975
2020	71,920	201,375
2019	121,977	44,919
2018	38,086	135,777
Prior to 2018	133,924	77,602
Revolving loan	174,556	178,416
Total	675,158	799,589
Financing Receivables Not Impaired | Nonaccrual loans | Domestic | Corporate | Small and medium sized companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	23,808	17,866
2021	14,072	20,110
2020	17,798	14,434
2019	8,410	10,817
2018	8,240	7,081
Prior to 2018	30,351	38,171
Revolving loan	29,840	32,081
Total	132,519	140,560
Financing Receivables Not Impaired | Nonaccrual loans | Foreign | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	0	0
2021	0	0
2020	0	643
2019	676	0
2018	0	0
Prior to 2018	0	0
Revolving loan	0	0
Total	676	643
Financing Receivables Not Impaired | Nonaccrual loans | Foreign | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	0	837
2021	0	0
2020	0	0
2019	0	0
2018	0	0
Prior to 2018	0	0
Revolving loan	0	0
Total	0	837
Financing Receivables Not Impaired | Nonaccrual loans | Foreign | Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	5,563	35,801
2021	35,354	1,622
2020	14,106	13,743
2019	51,952	17,181
2018	14,308	14,743
Prior to 2018	38,660	22,639
Revolving loan	9,983	9,745
Total	169,926	115,474
Financing Receivables Not Impaired | Nonaccrual loans | Foreign | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
2022	0	0
2021	0	0
2020	0	0
2019	0	0
2018	0	0
Prior to 2018	0	0
Revolving loan	0	0
Total	¥ 0	¥ 0

Loans - Credit Quality Inform_2

Loans - Credit Quality Information of Loans Based on MHFG Group's Internal Rating System (Parenthetical) (Detail) - JPY (¥) ¥ in Millions	Sep. 30, 2022	Mar. 31, 2022
Financing Receivables Impaired [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Direct Financing Lease, Lease Receivable	¥ 214,819	¥ 216,463

Loans - Impaired Loans Informat

Loans - Impaired Loans Information (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Mar. 31, 2022
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans with an allowance	¥ 995,862		¥ 1,082,154
Nonaccrual loans without an allowance	84,825		85,974
Total nonaccrual loans	1,080,687		1,168,128
Interest income recognized	13,160	¥ 9,380
Domestic
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans with an allowance	833,261		971,870
Nonaccrual loans without an allowance	76,824		79,304
Total nonaccrual loans	910,085		1,051,174
Interest income recognized	11,588	8,537
Domestic | Retail | Housing loan
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans with an allowance	23,491		26,812
Nonaccrual loans without an allowance	19,735		22,380
Total nonaccrual loans	43,226		49,192
Interest income recognized	399	477
Domestic | Retail | Other
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans with an allowance	38,446		40,155
Nonaccrual loans without an allowance	20,736		21,678
Total nonaccrual loans	59,182		61,833
Interest income recognized	377	406
Domestic | Large companies | Corporate
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans with an allowance	657,323		783,305
Nonaccrual loans without an allowance	17,835		16,284
Total nonaccrual loans	675,158		799,589
Interest income recognized	10,009	6,787
Domestic | Small and medium sized companies | Corporate
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans with an allowance	114,001		121,598
Nonaccrual loans without an allowance	18,518		18,962
Total nonaccrual loans	132,519		140,560
Interest income recognized	803	867
Foreign
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual loans with an allowance	162,601		110,284
Nonaccrual loans without an allowance	8,001		6,670
Total nonaccrual loans	170,602		¥ 116,954
Interest income recognized	¥ 1,572	¥ 843

Loans - Troubled Debt Restructu

Loans - Troubled Debt Restructurings Entered Modified Periods by Type of Concession Granted (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	¥ 0	¥ 5,849
Loan forgiveness or debt to equity swaps charge-offs	140,371	22,757
Interest rate reduction and/or postponement of principal and/or interest	345,790	472,594
Domestic
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	0	5,849
Loan forgiveness or debt to equity swaps charge-offs	140,371	22,757
Interest rate reduction and/or postponement of principal and/or interest	325,011	451,388
Domestic | Housing loan | Retail
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	0	0
Loan forgiveness or debt to equity swaps charge-offs	0	0
Interest rate reduction and/or postponement of principal and/or interest	3,257	4,996
Domestic | Other | Retail
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	0	0
Loan forgiveness or debt to equity swaps charge-offs	0	0
Interest rate reduction and/or postponement of principal and/or interest	9,557	10,288
Domestic | Large companies | Corporate
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	0	5,849
Loan forgiveness or debt to equity swaps charge-offs	140,371	22,757
Interest rate reduction and/or postponement of principal and/or interest	256,773	375,248
Domestic | Small and medium sized companies | Corporate
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	0	0
Loan forgiveness or debt to equity swaps charge-offs	0	0
Interest rate reduction and/or postponement of principal and/or interest	55,424	60,856
Foreign
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	0	0
Loan forgiveness or debt to equity swaps charge-offs	0	0
Interest rate reduction and/or postponement of principal and/or interest	¥ 20,779	¥ 21,206

Loans - Payment Defaults Occurr

Loans - Payment Defaults Occurred During Periods with Respect to Loans Modified as Troubled Debt Restructurings within Previous Six Months (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Financing Receivable, Modifications [Line Items]
Recorded investment	¥ 92,815	¥ 18,524
Domestic
Financing Receivable, Modifications [Line Items]
Recorded investment	92,815	4,399
Domestic | Corporate | Large companies
Financing Receivable, Modifications [Line Items]
Recorded investment	91,049	1,148
Domestic | Corporate | Small and medium sized companies
Financing Receivable, Modifications [Line Items]
Recorded investment	626	2,157
Domestic | Retail | Housing loan
Financing Receivable, Modifications [Line Items]
Recorded investment	418	579
Domestic | Retail | Other
Financing Receivable, Modifications [Line Items]
Recorded investment	722	515
Foreign
Financing Receivable, Modifications [Line Items]
Recorded investment	¥ 0	¥ 14,125

Loans - Age Analysis of Past Du

Loans - Age Analysis of Past Due Loans (Detail) - JPY (¥) ¥ in Millions	Sep. 30, 2022	Mar. 31, 2022
30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	¥ 20,849	¥ 20,651
30-59 Days Past Due | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	20,849	20,651
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	972	323
30-59 Days Past Due | Domestic | Corporate | Small and medium sized companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	809	693
30-59 Days Past Due | Domestic | Retail | Housing loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	14,486	15,181
30-59 Days Past Due | Domestic | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	4,582	4,454
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	0	0
60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	7,056	10,326
60-89 Days Past Due | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	7,056	10,326
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	291
60-89 Days Past Due | Domestic | Corporate | Small and medium sized companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	0	641
60-89 Days Past Due | Domestic | Retail | Housing loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	6,026	8,326
60-89 Days Past Due | Domestic | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	1,030	1,068
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	0	0
90 Days or More Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	121,594	94,018
90 Days or More Past Due | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	71,648	65,202
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	33,164	27,275
90 Days or More Past Due | Domestic | Corporate | Small and medium sized companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	11,330	10,370
90 Days or More Past Due | Domestic | Retail | Housing loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	16,024	16,548
90 Days or More Past Due | Domestic | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	11,130	11,009
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	49,946	28,816
Total past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	149,499	124,995
Total past due | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	99,553	96,179
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	34,136	27,889
Total past due | Domestic | Corporate | Small and medium sized companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	12,139	11,704
Total past due | Domestic | Retail | Housing loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	36,536	40,055
Total past due | Domestic | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	16,742	16,531
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	49,946	28,816
Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	98,184,792	90,165,588
Current | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	57,742,006	56,935,478
Current | Domestic | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	1,815,509	1,660,345
Current | Domestic | Corporate | Large companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	42,889,937	42,016,051
Current | Domestic | Corporate | Small and medium sized companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	3,046,405	3,145,216
Current | Domestic | Retail | Housing loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	7,605,545	7,741,465
Current | Domestic | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	1,611,053	1,690,644
Current | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	773,557	681,757
Current | Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	40,442,786	33,230,110
Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	98,334,291	90,290,583
Total | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	57,841,559	57,031,657
Total | Domestic | Soverign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	1,815,509	1,660,345
Total | Domestic | Corporate | Large companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	42,924,073	42,043,940
Total | Domestic | Corporate | Small and medium sized companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	3,058,544	3,156,920
Total | Domestic | Retail | Housing loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	7,642,081	7,781,520
Total | Domestic | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	1,627,795	1,707,175
Total | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	773,557	681,757
Total | Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable gross	¥ 40,492,732	¥ 33,258,926

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		6 Months Ended
		Sep. 30, 2022	Sep. 30, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period		¥ 809,817	¥ 650,849
Provision (credit) for credit losses on loans		38,539	48,205
Charge-offs	[1]	(163,612)	(40,896)
Recoveries		4,008	6,491
Net charge-offs		(159,604)	(34,405)
Others	[2]	21,994	579
Balance at end of period		710,746	665,228
Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	[3]	134,397	85,567
Provision (credit) for credit losses on loans	[3]	23,185	(5,155)
Charge-offs	[1],[3]	(14,403)	(12,570)
Recoveries	[3]	1,939	263
Net charge-offs	[3]	(12,464)	(12,307)
Others	[2],[3]	21,994	579
Balance at end of period	[3]	167,112	68,684
Corporate | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period		601,506	481,420
Provision (credit) for credit losses on loans		16,206	54,150
Charge-offs	[1]	(146,204)	(25,880)
Recoveries		1,309	5,312
Net charge-offs		(144,895)	(20,568)
Others	[2]	0	0
Balance at end of period		472,817	515,002
Retail | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period		73,414	83,171
Provision (credit) for credit losses on loans		(1,078)	(376)
Charge-offs	[1]	(3,005)	(2,446)
Recoveries		760	916
Net charge-offs		(2,245)	(1,530)
Others	[2]	0	0
Balance at end of period		70,091	81,265
Sovereign | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period		62	68
Provision (credit) for credit losses on loans		(4)	13
Charge-offs	[1]	0	0
Recoveries		0	0
Net charge-offs		0	0
Others	[2]	0	0
Balance at end of period		58	81
Banks and other financial institutions | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period		438	623
Provision (credit) for credit losses on loans		230	(427)
Charge-offs	[1]	0	0
Recoveries		0	0
Net charge-offs		0	0
Others	[2]	0	0
Balance at end of period		¥ 668	¥ 196
[1]Charge-offs increased by ¥122,716 million from the six months ended September 30, 2021 to ¥163,612 million for the six months ended September 30, 2022 due mainly to a debt waiver to a domestic corporate borrower.[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		6 Months Ended
		Sep. 30, 2022	Sep. 30, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-Offs	[1]	¥ 163,612	¥ 40,896
Debt Waiver To A Domestic Corporate Borrower [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-Offs		¥ 163,612	¥ 122,716
[1]Charge-offs increased by ¥122,716 million from the six months ended September 30, 2021 to ¥163,612 million for the six months ended September 30, 2022 due mainly to a debt waiver to a domestic corporate borrower.

Other Assets and Liabilities (D

Other Assets and Liabilities (Details of Other Assets and Liabilities) (Detail) - JPY (¥) ¥ in Millions		Sep. 30, 2022	Mar. 31, 2022
Other assets:
Receivables from brokers, dealers and customers for securities transactions		¥ 4,134,148	¥ 3,049,874
Other		438,670	557,842
Collateral pledged for derivative transactions		2,119,911	1,549,483
Margins provided for futures contracts		189,133	466,531
Other		1,086,446	1,006,849
Prepaid pension cost		747,563	762,147
Right-of-use assets		552,233	570,171
Security deposits		86,650	91,766
Loans held for sale		279,321	156,639
Other		885,359	775,940
Total		10,519,434	8,987,242
Other liabilities:
Payables to brokers, dealers and customers for securities transactions		1,662,194	1,406,965
Other		461,188	494,538
Guaranteed trust principal	[1]	821,670	810,776
Lease liabilities		¥ 574,190	¥ 593,339
Operating Lease, Liability, Statement of Financial Position [Extensible List]		Lease liabilities	Lease liabilities
Collateral accepted for derivative transactions		¥ 1,744,164	¥ 1,075,591
Margins accepted for futures contracts		131,007	327,883
Unearned income		109,425	113,181
Other		1,516,457	1,437,949
Total		¥ 7,020,295	¥ 6,260,222
[1]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 15 “Variable interest entities and securitizations” for further discussion of the guaranteed principal money trusts.

Preferred and Common Stock (Com

Preferred and Common Stock (Composition of Preferred Stock) (Detail) - shares	Sep. 30, 2022	Mar. 31, 2022
Class Fourteen Preferred Stock
Class of Stock [Line Items]
Number of shares Authorized	90,000,000	90,000,000
Number of shares Issued	0	0
Class Fifteen Preferred Stock
Class of Stock [Line Items]
Number of shares Authorized	90,000,000	90,000,000
Number of shares Issued	0	0
Class Sixteen Preferred Stock
Class of Stock [Line Items]
Number of shares Authorized	150,000,000	150,000,000
Number of shares Issued	0	0

Preferred and Common Stock - Ad

Preferred and Common Stock - Additional Information (Detail) - shares	Sep. 30, 2022	Mar. 31, 2022
Class of Stock [Line Items]
Common Stock, Shares, Issued	2,539,249,894	2,539,249,894

Accumulated other comprehensi_3

Accumulated other comprehensive income (loss), net of tax (Changes in Each Component of Accumulated Other Comprehensive Income (Loss), Net of Tax AOCI) (Detail) - JPY (¥) ¥ in Millions		6 Months Ended
		Sep. 30, 2022	Sep. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period		¥ 9,442,231
Less: reclassification adjustments for losses (gains) included in net income		(13,481)
Change during period		260,349	¥ 38,196
Balance at end of period		9,437,041	10,042,141
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	[1]	440,112	318,114
Change during period	[1]	258,723	37,671
Balance at end of period	[1]	698,835	355,785
Net unrealized gains (losses) on available-for-sale securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period		(25,046)	(8,173)
Unrealized holding gains (losses) during period		(4,329)	6,034
Less: reclassification adjustments for losses (gains) included in net income		(4,741)	(525)
Change during period		(9,070)	5,509
Balance at end of period		(34,116)	(2,664)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period		94,104	(86,873)
Foreign currency translation adjustments during period		269,154	52,231
Less: reclassification adjustments for losses (gains) included in net income		0	0
Change during period		269,154	52,231
Balance at end of period		363,258	(34,642)
Defined benefit plan adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period		355,355	397,153
Unrealized holding gains (losses) during period		4,390	(5,107)
Less: reclassification adjustments for losses (gains) included in net income		(9,183)	(9,187)
Change during period		(4,793)	(14,294)
Balance at end of period		350,562	382,859
Accumulated Own Credit Risk Adjustment Including Portion Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period		15,699	16,007
Unrealized holding gains (losses) during period		2,998	(6,218)
Less: reclassification adjustments for losses (gains) included in net income		434	443
Change during period		3,432	(5,775)
Balance at end of period		¥ 19,131	¥ 10,232
[1]The amounts that have been reclassified out of Accumulated other comprehensive income (loss), net of tax into net income are presented in Note 8 “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	6 Months Ended
	Sep. 30, 2022 JPY (¥)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Before tax	¥ 19,247	[1]
Tax effect	(5,766)	[2]
Net of tax before allocation to noncontrolling interests	13,481
Net of tax attributable to noncontrolling interests	9	[2]
Net of tax attributable to MHFG shareholders	13,490
Accumulated Net Unrealized Investment Gain (Loss) | Gain (Loss) on Investments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Before tax	6,759	[1]
Tax effect	(2,018)	[2]
Net of tax before allocation to noncontrolling interests	4,741
Net of tax attributable to noncontrolling interests	0	[2]
Net of tax attributable to MHFG shareholders	4,741
Accumulated Defined Benefit Plans Adjustment | Salaries and employee benefits
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Before tax	13,114	[1]
Tax effect	(3,940)	[2]
Net of tax before allocation to noncontrolling interests	9,174
Net of tax attributable to noncontrolling interests	9	[2]
Net of tax attributable to MHFG shareholders	9,183
Accumulated Own Credit Risk Adjustment | Other Noninterest Income (Expenses)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Before tax	(626)	[1]
Tax effect	192	[2]
Net of tax before allocation to noncontrolling interests	(434)
Net of tax attributable to noncontrolling interests	0	[2]
Net of tax attributable to MHFG shareholders	¥ (434)
[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 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 Billions		Sep. 30, 2022	Mar. 31, 2022
Mizuho Financial Group Inc | Consolidated
Common Equity Tier 1 capital:
Required, amount	[1]	¥ 5,714	¥ 5,184
Actual		8,097	8,067
Required, amount	[1]	6,784	6,155
Actual		¥ 9,733	¥ 9,713
Required, ratio	[1]	9.51%	9.51%
Actual		13.64%	15%
Required, amount	[1]	¥ 8,210	¥ 7,450
Actual		¥ 11,216	¥ 11,351
Required, ratio	[1]	11.51%	11.51%
Actual		15.72%	17.53%
Required, amount	[2]	¥ 6,925	¥ 6,389
Actual	[2]	¥ 9,733	¥ 9,713
Common Equity Tier 1 capital:
Required, ratio	[1]	8.01%	8.01%
Actual		11.35%	12.46%
Leverage Ratio:
Required, ratio	[2]	3%	3%
Actual	[2]	4.21%	4.56%
Mizuho Bank Limited | Consolidated
Common Equity Tier 1 capital:
Required, amount		¥ 2,981	¥ 2,683
Actual		7,082	6,968
Required, amount		3,975	3,578
Actual		¥ 8,714	¥ 8,604
Required, ratio		6%	6%
Actual		13.15%	14.42%
Required, amount		¥ 5,300	¥ 4,771
Actual		¥ 10,110	¥ 10,150
Required, ratio		8%	8%
Actual		15.26%	17.02%
Required, amount	[2]	¥ 6,509	¥ 5,971
Actual	[2]	¥ 8,714	¥ 8,604
Common Equity Tier 1 capital:
Required, ratio		4.50%	4.50%
Actual		10.68%	11.68%
Leverage Ratio:
Required, ratio	[2]	3%	3%
Actual	[2]	4.01%	4.32%
Mizuho Bank Limited | Non-consolidated
Common Equity Tier 1 capital:
Required, amount		¥ 2,783	¥ 2,528
Actual		6,066	6,293
Required, amount		3,710	3,370
Actual		¥ 7,689	¥ 7,919
Required, ratio		6%	6%
Actual		12.43%	14.09%
Required, amount		¥ 4,947	¥ 4,494
Actual		¥ 9,097	¥ 9,483
Required, ratio		8%	8%
Actual		14.70%	16.88%
Required, amount	[2]	¥ 6,048	¥ 5,570
Actual	[2]	¥ 7,689	¥ 7,919
Common Equity Tier 1 capital:
Required, ratio		4.50%	4.50%
Actual		9.80%	11.20%
Leverage Ratio:
Required, ratio	[2]	3%	3%
Actual	[2]	3.81%	4.26%
Mizuho Trust & Banking Company Limited | Consolidated
Common Equity Tier 1 capital:
Required, amount		¥ 76	¥ 79
Actual		453	442
Required, amount		102	105
Actual		¥ 453	¥ 442
Required, ratio		6%	6%
Actual		26.62%	25.18%
Required, amount		¥ 136	¥ 140
Actual		¥ 453	¥ 442
Required, ratio		8%	8%
Actual		26.62%	25.18%
Required, amount	[2]	¥ 128	¥ 130
Actual	[2]	¥ 453	¥ 442
Common Equity Tier 1 capital:
Required, ratio		4.50%	4.50%
Actual		26.62%	25.18%
Leverage Ratio:
Required, ratio	[2]	3%	3%
Actual	[2]	10.56%	10.20%
Mizuho Trust & Banking Company Limited | Non-consolidated
Common Equity Tier 1 capital:
Required, amount		¥ 76	¥ 78
Actual		436	425
Required, amount		101	104
Actual		¥ 436	¥ 425
Required, ratio		6%	6%
Actual		25.68%	24.40%
Required, amount		¥ 135	¥ 139
Actual		¥ 436	¥ 425
Required, ratio		8%	8%
Actual		25.69%	24.40%
Required, amount	[2]	¥ 124	¥ 126
Actual	[2]	¥ 436	¥ 425
Common Equity Tier 1 capital:
Required, ratio		4.50%	4.50%
Actual		25.68%	24.40%
Leverage Ratio:
Required, ratio	[2]	3%	3%
Actual	[2]	10.47%	10.09%
[1]The required ratios disclosed above, at March 31, 2022 and September 30, 2022, include the capital conservation buffer of 2.5%, the countercyclical capital buffer of 0.01%, and the additional loss absorbency requirements for global systemically important banks (“G-SIBs”) and domestic systemically important banks (“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, 2022 and September 30, 2022 exclude amounts of deposits to the Bank of Japan.

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)	6 Months Ended	12 Months Ended
	Sep. 30, 2022	Mar. 31, 2022
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Capital conservation buffer	2.50%	2.50%
March 2020
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Countercyclical capital buffer	0.01%	0.01%
March 2021
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%

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		6 Months Ended
		Sep. 30, 2022	Sep. 30, 2021
Net income (loss):
Net income (loss) attributable to MHFG common shareholders		¥ (378,877)	¥ 312,657
Effect of dilutive securities
Effect of dilutive securities		0
Net income (loss) attributable to common shareholders after assumed conversions		¥ (378,877)	¥ 312,657
Shares:
Weighted average common shares outstanding		2,536,315	2,536,902
Effect of dilutive securities:
Stock options and the common shares of MHFG under the stock compensation programs			119
Weighted average common shares after assumed conversions		2,536,315	2,537,021
Earnings per common share:
Basic net income (loss) per common share		¥ (149.38)	¥ 123.24
Diluted net income (loss) per common share	[1]	¥ (149.38)	¥ 123.24
[1]For the six months ended September 30, 2022, 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 six months ended September 30, 2022, 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	6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Reconciliation of Provision of Income Taxes [Line Items]
Current tax expense	¥ 67,244	¥ 67,822
Deferred tax expense (benefit)	(239,149)	(28,200)
Total income tax expense (benefit)	¥ (171,905)	¥ 39,622

Income Taxes (Detailed Amounts

Income Taxes (Detailed Amounts of Tax Effects of Items Recorded Directly in Equity) (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Net unrealized gains (losses) on available-for-sale securities:
Unrealized gains (losses)	¥ (3,413)	¥ 926
Less: reclassification adjustments	(2,018)	(213)
Total	(5,431)	713
Defined benefit plan adjustments:
Unrealized gains (losses)	1,381	(2,144)
Less: reclassification adjustments	(3,940)	(3,875)
Total	(2,559)	(6,019)
Own credit risk adjustments:
Unrealized gains (losses)	1,368	(2,638)
Less: reclassification adjustments	192	219
Total	1,560	(2,419)
Total tax effect before allocation to noncontrolling interests	¥ (6,430)	¥ (7,725)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Income Taxes [Line Items]
Statutory tax rate	30.62%	30.62%
Effective tax rate	30.55%	10.34%
Net operating loss carryforwards	¥ 571,000
Unrecognized Tax Benefits	¥ 6,567

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	6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Defined Benefit Plan Disclosure [Line Items]
Service cost-benefits earned during the period	¥ 14,559	¥ 16,365
Interest costs on projected benefit obligations	3,626	2,700
Expected return on plan assets	(18,050)	(18,478)
Amortization of prior service cost (benefits)	(2,410)	(2,410)
Amortization of net actuarial loss (gain)	(9,741)	(10,263)
Special termination benefits	3,831	4,154
Net periodic benefit cost	¥ (8,185)	¥ (7,932)

Derivative Financial Instrume_3

Derivative Financial Instruments (Summary of Notional and Fair Value Amounts of Derivative Instruments Outstanding) (Detail) - JPY (¥) ¥ in Billions		Sep. 30, 2022	Mar. 31, 2022
Derivatives, Fair Value [Line Items]
Notional amount	[1]	¥ 1,917,804	¥ 1,635,837
Interest rate contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	1,627,102	1,395,950
Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	260,472	217,462
Equity-related contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	7,735	9,887
Credit-related contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	21,379	11,857
Other contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	1,116	681
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	18,030	9,723
Fair value of derivative payables	[2]	18,294	9,770
Not Designated as Hedging Instrument | Interest rate contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	8,916	4,624
Fair value of derivative payables	[2]	9,229	4,716
Not Designated as Hedging Instrument | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	8,571	4,436
Fair value of derivative payables	[2]	8,665	4,472
Not Designated as Hedging Instrument | Equity-related contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	285	426
Fair value of derivative payables	[2]	214	345
Not Designated as Hedging Instrument | Credit-related contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	166	118
Fair value of derivative payables	[2]	94	121
Not Designated as Hedging Instrument | Other contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	92	119
Fair value of derivative payables	[2]	¥ 92	¥ 116
[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	Sep. 30, 2022	Mar. 31, 2022
Derivative [Line Items]
Cash collateral provided and not offset against derivative positions and included in Other assets	¥ 2,119,911	¥ 1,549,483
Cash collateral accepted and not offset against derivative positions and included in Other liabilities	¥ 1,744,164	¥ 1,075,591

Derivative Financial Instrume_5

Derivative Financial Instruments (Summary of Gains and Losses on Derivatives not Designated or Qualifying as Hedges) (Detail) - JPY (¥) ¥ in Millions		6 Months Ended
		Sep. 30, 2022	Sep. 30, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		¥ 656,663	¥ 52,789
Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		(179,783)	20,602
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		251,060	7,407
Equity-related contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		482,233	33,504
Credit-related contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income	[1]	42,152	(15,599)
Other contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		¥ 61,001	¥ 6,875
[1]Amounts include the net gains (losses) of ¥(395) million and ¥172 million on the credit derivatives economically managing the credit risk of loans during the six months ended September 30, 2021 and 2022, respectively.

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		6 Months Ended
		Sep. 30, 2022	Sep. 30, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		¥ 656,663	¥ 52,789
Credit-related contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income	[1]	42,152	(15,599)
Credit-related contracts | Loans related to credit derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		¥ 172	¥ (395)
[1]Amounts include the net gains (losses) of ¥(395) million and ¥172 million on the credit derivatives economically managing the credit risk of loans during the six months ended September 30, 2021 and 2022, respectively.

Derivative Financial Instrume_7

Derivative Financial Instruments (Summary of Notional and Fair Value Amounts of Credit Derivatives) (Detail) - JPY (¥) ¥ in Billions	Sep. 30, 2022	Mar. 31, 2022
Credit protection written
Credit Derivatives [Line Items]
Notional amount	¥ 9,866	¥ 5,167
Fair value	(41)	92
Credit protection written | Investment grade
Credit Derivatives [Line Items]
Notional amount	4,370	3,045
Fair value		38
Credit protection written | Non-investment grade
Credit Derivatives [Line Items]
Notional amount	5,496	2,122
Fair value	(41)	54
Credit protection purchased
Credit Derivatives [Line Items]
Notional amount	11,513	6,690
Fair value	¥ 113	¥ (95)

Derivative Financial Instrume_8

Derivative Financial Instruments (Maximum Potential Amount of Future Payments for Credit Protection Written by Expiration Period) (Detail) - JPY (¥) ¥ in Billions	Sep. 30, 2022	Mar. 31, 2022
Credit Derivatives [Line Items]
Maximum payout/Notional amount	¥ 9,866	¥ 5,167
One year or less
Credit Derivatives [Line Items]
Maximum payout/Notional amount	242	245
After one year through five years
Credit Derivatives [Line Items]
Maximum payout/Notional amount	9,239	4,785
After five years
Credit Derivatives [Line Items]
Maximum payout/Notional amount	¥ 385	¥ 137

Derivative Financial Instrume_9

Derivative Financial Instruments (Quantitative Information about Derivative Instruments with Credit-risk-related Contingent Features) (Detail) - JPY (¥) ¥ in Billions	Sep. 30, 2022	Mar. 31, 2022
Credit Derivatives [Line Items]
Aggregate fair value of derivative instruments with credit-risk-related contingent features in net liability positions	¥ 1,866	¥ 1,149
Collateral provided to counterparties in the normal course of business	1,743	1,164
Amount required to be posted as collateral or settled immediately if credit-risk-related contingent features were triggered	¥ 123	¥ 0

Commitments and Contingencies_2

Commitments and Contingencies (Summary of Maximum Potential Amount of Future Payments under Guarantees) (Detail) - JPY (¥) ¥ in Billions	Sep. 30, 2022	Mar. 31, 2022
Performance guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	¥ 3,612	¥ 3,254
Guarantees on loans
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	409	419
Guarantees on securities
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	89	75
Other guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	3,683	2,899
Guarantees for repayment of trust principal
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	19	22
Liabilities of trust accounts
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	529	478
Derivative financial instruments
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	¥ 44,900	¥ 36,484

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		Sep. 30, 2022	Mar. 31, 2022
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount		¥ 7,793	¥ 6,647
Investment grade
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	[1]	6,228	5,336
Non-investment grade
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount		¥ 1,565	¥ 1,311
[1]Investment grade in the internal rating scale generally corresponds to BBB- or above in the external rating scale.

Commitments and Contingencies_4

Commitments and Contingencies (Summary of Contractual Amounts with Regard to Undrawn Commitments) (Detail) - JPY (¥) ¥ in Billions		Sep. 30, 2022	Mar. 31, 2022
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance-sheet instruments, contractual amounts of the undrawn commitments		¥ 101,561	¥ 93,625
Commitments to Extend Credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance-sheet instruments, contractual amounts of the undrawn commitments	[1]	99,960	92,203
Commercial letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance-sheet instruments, contractual amounts of the undrawn commitments		¥ 1,601	¥ 1,422
[1]Commitments to extend credit include commitments to invest in securities.

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	Sep. 30, 2022	Mar. 31, 2022
Variable Interest Entity [Line Items]
Total assets of MHFG	¥ 250,751,368	¥ 231,550,704
Significant unconsolidated VIEs- Maximum exposure to loss	809,000	809,000
Consolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	12,174,665	11,574,978
Unconsolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	3,151,000	3,582,000
Asset-backed commercial paper/loan programs | Consolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	2,991,000	2,709,000
Asset-backed securitizations
Variable Interest Entity [Line Items]
Significant unconsolidated VIEs- Maximum exposure to loss	121,000	90,000
Asset-backed securitizations | Consolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	1,653,000	1,363,000
Asset-backed securitizations | Unconsolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	199,000	190,000
Investments in securitization products | Consolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	387,000	388,000
Investment funds
Variable Interest Entity [Line Items]
Significant unconsolidated VIEs- Maximum exposure to loss	688,000	719,000
Investment funds | Consolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	2,060,000	1,816,000
Investment funds | Unconsolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	2,952,000	3,392,000
Trust arrangements and other | Consolidated VIEs
Variable Interest Entity [Line Items]
Total assets of MHFG	¥ 5,084,000	¥ 5,299,000

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		Sep. 30, 2022	Mar. 31, 2022
Assets on consolidated balance sheets
Trading account assets		¥ 35,330,944	¥ 24,652,067
Loans		97,623,545	89,480,766
Total assets		250,751,368	231,550,704
Liabilities on MHFG's consolidated balance sheets and maximum exposure to loss related to unconsolidated VIEs
Payables under securities lending transactions		1,490,659	1,360,743
Trading account liabilities		24,229,013	14,859,383
Total		241,314,327	222,108,473
Maximum exposure to loss		809,000	809,000
Unconsolidated VIEs
Assets on consolidated balance sheets
Total assets		3,151,000	3,582,000
Mizuho Financial Group Inc | Unconsolidated VIEs
Assets on consolidated balance sheets
Trading account assets		152,000	143,000
Investments		373,000	430,000
Loans		115,000	92,000
Total assets		640,000	665,000
Liabilities on MHFG's consolidated balance sheets and maximum exposure to loss related to unconsolidated VIEs
Payables under securities lending transactions		59,000	54,000
Trading account liabilities		2,000	2,000
Total		61,000	56,000
Maximum exposure to loss	[1]	¥ 809,000	¥ 809,000
[1]This represents the maximum amount the Group could possibly be required to record in its consolidated statements of income associated with on-balance-sheet exposures and off-balance-sheet liabilities such as undrawn commitments.

Variable Interest Entities an_5

Variable Interest Entities and Securitizations - Additional Information (Detail) - JPY (¥) ¥ in Millions	Sep. 30, 2022	Mar. 31, 2022
Consolidated MHFG's balance sheets
Long-term debt	¥ 13,546,803	¥ 12,578,216
Noncontrolling interests	729,336	528,019
Unconsolidated VIEs
Consolidated MHFG's balance sheets
Noncontrolling interests	641,000	388,000
Debt Instrument [Member]
Consolidated MHFG's balance sheets
Long-term debt	217,000	367,000
Assets associated with securitization transactions
Consolidated MHFG's balance sheets
Transferred assets continue to be carried on the consolidated balance sheets	145,000	137,000
Assets associated with loan participation transactions
Consolidated MHFG's balance sheets
Transferred assets continue to be carried on the consolidated balance sheets	¥ 236,000	¥ 220,000

Summary of Noninterest Income (

Summary of Noninterest Income (Detail) - JPY (¥) ¥ in Millions		6 Months Ended
		Sep. 30, 2022	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Fee and commission income		¥ 448,744	¥ 474,916
Foreign exchange gains (losses)—net		128,897	21,708
Trading account gains (losses)—net		(851,080)	83,255
Investment gains (losses)—net:
Debt securities		8,057	(317)
Equity securities		(113,461)	135,070
Equity in earnings (losses) of equity method investees—net	[1]	(5,003)	16,541
Gains on disposal of premises and equipment	[1]	1,811	1,988
Other noninterest income	[2],[3]	168,254	29,234
Total noninterest income		(213,781)	762,395
Foreign Exchange
Disaggregation of Revenue [Line Items]
Foreign exchange gains (losses)—net	[1]	128,897	21,708
Trading Account Gains
Disaggregation of Revenue [Line Items]
Trading account gains (losses)—net	[2]	(851,080)	83,255
Debt securities
Investment gains (losses)—net:
Debt securities	[1]	8,057	(317)
Equity securities
Investment gains (losses)—net:
Equity securities	[1]	(113,461)	135,070
Securities related business
Disaggregation of Revenue [Line Items]
Fee and commission income	[4]	74,804	89,387
Deposits related business
Disaggregation of Revenue [Line Items]
Fee and commission income	[4]	7,769	7,569
Lending related business
Disaggregation of Revenue [Line Items]
Fee and commission income	[2],[5]	79,811	78,053
Remittance business
Disaggregation of Revenue [Line Items]
Fee and commission income	[4]	52,410	54,576
Investment advisory, management and administrative service
Disaggregation of Revenue [Line Items]
Fee and commission income	[4]	55,508	60,596
Fiduciary and trust
Disaggregation of Revenue [Line Items]
Fee and commission income	[4]	57,395	66,393
Agency business
Disaggregation of Revenue [Line Items]
Fee and commission income	[4]	18,399	18,573
Guarantee-related business
Disaggregation of Revenue [Line Items]
Fee and commission income	[1]	20,680	16,781
Financial service, other
Disaggregation of Revenue [Line Items]
Fee and commission income	[4]	81,968	82,988
Financial service
Disaggregation of Revenue [Line Items]
Fee and commission income		¥ 448,744	¥ 474,916
[1]These amounts are revenues from contracts that do not meet the scope of 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 include the net unrealized gains resulting from changes in fair values of structured notes that contain embedded derivatives. See Note 17 “Fair value” for further details.[4]These amounts are revenues from contracts within the scope of ASC 606, “Revenue from contracts with customers” (“ASC 606”).[5]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		6 Months Ended
		Sep. 30, 2022	Sep. 30, 2021
Other Revenues [Line Items]
Trust fees		¥ 27,000	¥ 28,000
Fees related to trust business		30,000	38,000
Trading account gains (losses)—net		(851,080)	83,255
Other noninterest income	[1],[2]	168,254	29,234
Revenue from contracts with customers ("ASC 606")
Other Revenues [Line Items]
Trading account gains (losses)—net		24,000	42,000
Other noninterest income		¥ 9,000	¥ 7,000
[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 17 “Fair value” for further details.

Fair Value - Additional Informa

Fair Value - Additional Information (Detail) - JPY (¥) ¥ in Billions	6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	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	¥ 193		¥ 207
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	221		¥ 90
Net unrealized gains (losses) resulting from changes in fair values of the notes	¥ 128	¥ (30)
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 out of Level 3	¥ 0	1
Fair value of liabilities transferred into Level 3	1	1
Derivative liabilities, net
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of assets transferred into Level 3		1
Trading securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of assets transferred into Level 3	8
Fair value of assets transferred out of Level 3	1	¥ 1
Available-for-sale securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of liabilities transferred out of Level 3	¥ 9

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		Sep. 30, 2022	Mar. 31, 2022
Assets:
Available-for-sale securities		¥ 23,743,660	¥ 31,673,890
Liabilities:
Long-term debt		2,736,380	2,756,062
Fair Value, Measurements, Recurring
Assets:
Equity securities with readily determinable fair values		2,968,000	3,155,000
Equity securities measured at net asset value	[1]	278,000	210,000
Other investments		64,000	58,000
Total assets measured at fair value		62,385,000	59,749,000
Liabilities:
Trading securities sold, not yet purchased		5,935,000	5,089,000
Long-term debt	[2]	2,736,000	2,756,000
Total liabilities measured at fair value		26,965,000	17,615,000
Fair Value, Measurements, Recurring | Trading Account Asset
Assets:
Securities measured at net asset value	[1],[3]	140,000	284,000
Fair Value, Measurements, Recurring | Interest rate contracts
Assets:
Assets, derivatives		8,916,000	4,624,000
Liabilities:
Liabilities, derivatives		9,229,000	4,716,000
Fair Value, Measurements, Recurring | Foreign exchange contracts
Assets:
Assets, derivatives		8,571,000	4,436,000
Liabilities:
Liabilities, derivatives		8,665,000	4,472,000
Fair Value, Measurements, Recurring | Equity-related contracts
Assets:
Assets, derivatives		285,000	426,000
Liabilities:
Liabilities, derivatives		214,000	345,000
Fair Value, Measurements, Recurring | Credit-related contracts
Assets:
Assets, derivatives		166,000	118,000
Liabilities:
Liabilities, derivatives		94,000	121,000
Fair Value, Measurements, Recurring | Other contracts
Assets:
Assets, derivatives		92,000	119,000
Liabilities:
Liabilities, derivatives		92,000	116,000
Fair Value, Measurements, Recurring | Japanese government bonds
Assets:
Assets, trading securities	[3]	1,869,000	1,615,000
Available-for-sale securities		17,103,000	25,159,000
Fair Value, Measurements, Recurring | Japanese local government bonds
Assets:
Assets, trading securities	[3]	99,000	145,000
Available-for-sale securities		497,000	420,000
Fair Value, Measurements, Recurring | U.S. Treasury bonds and federal agency securities
Assets:
Assets, trading securities	[3]	4,037,000	3,064,000
Available-for-sale securities		435,000	373,000
Fair Value, Measurements, Recurring | Other foreign government bonds
Assets:
Assets, trading securities	[3]	1,699,000	1,546,000
Available-for-sale securities		1,280,000	1,336,000
Fair Value, Measurements, Recurring | Agency mortgage-backed securities
Assets:
Assets, trading securities	[3]	4,068,000	3,176,000
Available-for-sale securities		494,000	451,000
Fair Value, Measurements, Recurring | Residential mortgage-backed securities
Assets:
Assets, trading securities	[3]	7,000	8,000
Available-for-sale securities		52,000	58,000
Fair Value, Measurements, Recurring | Commercial mortgage-backed securities
Assets:
Available-for-sale securities		869,000	854,000
Fair Value, Measurements, Recurring | Certificates of deposit and commercial paper
Assets:
Assets, trading securities	[3]	797,000	640,000
Fair Value, Measurements, Recurring | Corporate bonds and other debt securities
Assets:
Assets, trading securities	[3],[4]	2,757,000	2,829,000
Fair Value, Measurements, Recurring | Equity securities
Assets:
Assets, trading securities	[3]	1,828,000	1,622,000
Fair Value, Measurements, Recurring | Japanese corporate bonds and other debt securities
Assets:
Available-for-sale securities		2,122,000	2,235,000
Fair Value, Measurements, Recurring | Foreign corporate bonds and other debt securities
Assets:
Available-for-sale securities		892,000	788,000
Fair Value, Measurements, Recurring | Level 1
Assets:
Equity securities with readily determinable fair values		2,913,000	3,094,000
Other investments			2,000
Total assets measured at fair value		27,660,000	34,969,000
Liabilities:
Trading securities sold, not yet purchased		2,602,000	3,054,000
Total liabilities measured at fair value		2,884,000	3,284,000
Fair Value, Measurements, Recurring | Level 1 | Interest rate contracts
Assets:
Assets, derivatives		202,000	89,000
Liabilities:
Liabilities, derivatives		185,000	80,000
Fair Value, Measurements, Recurring | Level 1 | Equity-related contracts
Assets:
Assets, derivatives		96,000	77,000
Liabilities:
Liabilities, derivatives		69,000	122,000
Fair Value, Measurements, Recurring | Level 1 | Other contracts
Assets:
Assets, derivatives		36,000	49,000
Liabilities:
Liabilities, derivatives		28,000	28,000
Fair Value, Measurements, Recurring | Level 1 | Japanese government bonds
Assets:
Assets, trading securities	[3]	1,858,000	1,604,000
Available-for-sale securities		16,366,000	24,662,000
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury bonds and federal agency securities
Assets:
Assets, trading securities	[3]	2,908,000	2,353,000
Available-for-sale securities		435,000	373,000
Fair Value, Measurements, Recurring | Level 1 | Other foreign government bonds
Assets:
Assets, trading securities	[3]	863,000	907,000
Available-for-sale securities		279,000	363,000
Fair Value, Measurements, Recurring | Level 1 | Corporate bonds and other debt securities
Assets:
Assets, trading securities	[3],[4]	83,000	15,000
Fair Value, Measurements, Recurring | Level 1 | Equity securities
Assets:
Assets, trading securities	[3]	1,621,000	1,381,000
Fair Value, Measurements, Recurring | Level 2
Assets:
Equity securities with readily determinable fair values		55,000	61,000
Total assets measured at fair value		33,672,000	23,539,000
Liabilities:
Trading securities sold, not yet purchased		3,333,000	2,035,000
Long-term debt	[2]	1,930,000	1,962,000
Total liabilities measured at fair value		23,179,000	13,444,000
Fair Value, Measurements, Recurring | Level 2 | Interest rate contracts
Assets:
Assets, derivatives		8,663,000	4,513,000
Liabilities:
Liabilities, derivatives		9,043,000	4,636,000
Fair Value, Measurements, Recurring | Level 2 | Foreign exchange contracts
Assets:
Assets, derivatives		8,529,000	4,404,000
Liabilities:
Liabilities, derivatives		8,662,000	4,472,000
Fair Value, Measurements, Recurring | Level 2 | Equity-related contracts
Assets:
Assets, derivatives		161,000	323,000
Liabilities:
Liabilities, derivatives		95,000	183,000
Fair Value, Measurements, Recurring | Level 2 | Credit-related contracts
Assets:
Assets, derivatives		164,000	116,000
Liabilities:
Liabilities, derivatives		90,000	120,000
Fair Value, Measurements, Recurring | Level 2 | Other contracts
Assets:
Assets, derivatives		18,000	18,000
Liabilities:
Liabilities, derivatives		26,000	36,000
Fair Value, Measurements, Recurring | Level 2 | Japanese government bonds
Assets:
Assets, trading securities	[3]	11,000	11,000
Available-for-sale securities		737,000	497,000
Fair Value, Measurements, Recurring | Level 2 | Japanese local government bonds
Assets:
Assets, trading securities	[3]	99,000	145,000
Available-for-sale securities		497,000	420,000
Fair Value, Measurements, Recurring | Level 2 | U.S. Treasury bonds and federal agency securities
Assets:
Assets, trading securities	[3]	1,129,000	711,000
Fair Value, Measurements, Recurring | Level 2 | Other foreign government bonds
Assets:
Assets, trading securities	[3]	836,000	639,000
Available-for-sale securities		1,001,000	973,000
Fair Value, Measurements, Recurring | Level 2 | Agency mortgage-backed securities
Assets:
Assets, trading securities	[3]	4,068,000	3,176,000
Available-for-sale securities		494,000	451,000
Fair Value, Measurements, Recurring | Level 2 | Residential mortgage-backed securities
Assets:
Available-for-sale securities		37,000	40,000
Fair Value, Measurements, Recurring | Level 2 | Commercial mortgage-backed securities
Assets:
Available-for-sale securities		869,000	854,000
Fair Value, Measurements, Recurring | Level 2 | Certificates of deposit and commercial paper
Assets:
Assets, trading securities	[3]	797,000	640,000
Fair Value, Measurements, Recurring | Level 2 | Corporate bonds and other debt securities
Assets:
Assets, trading securities	[3],[4]	2,603,000	2,743,000
Fair Value, Measurements, Recurring | Level 2 | Equity securities
Assets:
Assets, trading securities	[3]	181,000	213,000
Fair Value, Measurements, Recurring | Level 2 | Japanese corporate bonds and other debt securities
Assets:
Available-for-sale securities		1,992,000	1,920,000
Fair Value, Measurements, Recurring | Level 2 | Foreign corporate bonds and other debt securities
Assets:
Available-for-sale securities		731,000	671,000
Fair Value, Measurements, Recurring | Level 3
Assets:
Other investments		64,000	56,000
Total assets measured at fair value		635,000	747,000
Liabilities:
Long-term debt	[2]	806,000	794,000
Total liabilities measured at fair value		902,000	887,000
Fair Value, Measurements, Recurring | Level 3 | Interest rate contracts
Assets:
Assets, derivatives		51,000	22,000
Liabilities:
Liabilities, derivatives		1,000
Fair Value, Measurements, Recurring | Level 3 | Foreign exchange contracts
Assets:
Assets, derivatives		42,000	32,000
Liabilities:
Liabilities, derivatives		3,000
Fair Value, Measurements, Recurring | Level 3 | Equity-related contracts
Assets:
Assets, derivatives		28,000	26,000
Liabilities:
Liabilities, derivatives		50,000	40,000
Fair Value, Measurements, Recurring | Level 3 | Credit-related contracts
Assets:
Assets, derivatives		2,000	2,000
Liabilities:
Liabilities, derivatives		4,000	1,000
Fair Value, Measurements, Recurring | Level 3 | Other contracts
Assets:
Assets, derivatives		38,000	52,000
Liabilities:
Liabilities, derivatives		38,000	52,000
Fair Value, Measurements, Recurring | Level 3 | Residential mortgage-backed securities
Assets:
Assets, trading securities	[3]	7,000	8,000
Available-for-sale securities		15,000	18,000
Fair Value, Measurements, Recurring | Level 3 | Corporate bonds and other debt securities
Assets:
Assets, trading securities	[3],[4]	71,000	71,000
Fair Value, Measurements, Recurring | Level 3 | Equity securities
Assets:
Assets, trading securities	[3]	26,000	28,000
Fair Value, Measurements, Recurring | Level 3 | Japanese corporate bonds and other debt securities
Assets:
Available-for-sale securities		130,000	315,000
Fair Value, Measurements, Recurring | Level 3 | Foreign corporate bonds and other debt securities
Assets:
Available-for-sale securities		¥ 161,000	¥ 117,000
[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, 2022 and September 30, 2022 were ¥68 billion and ¥61 billion, respectively.[2]Amounts represent items for which the Group elected the fair value option or for which it applied the practicability exception.[3]Trading securities include foreign currency denominated securities for which the MHFG Group elected the fair value option.[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	Sep. 30, 2022	Mar. 31, 2022
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unfunded commitments	¥ 61	¥ 68

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		6 Months Ended
		Sep. 30, 2022	Sep. 30, 2021
Trading securities sold, not yet purchased
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		¥ 0	¥ 0
Gains (losses) in Earnings	[1]	0	0
Gains (losses) in OCI		0	0
Transfers into Level 3		0	0
Transfers out of level 3		0	0
Purchases		0	(1)
Sales		0	1
Issuances		0	0
Settlements		0	0
Ending Balance		0	0
Change in unrealized gain (losses) still held	[2]	0	0
Long-term debt
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		794	713
Gains (losses) in Earnings	[3]	96	6
Gains (losses) in OCI	[4]	6	(5)
Transfers into Level 3		1	1
Transfers out of level 3		0	(1)
Purchases		0	0
Sales		0	0
Issuances		201	256
Settlements		(88)	(216)
Ending Balance		806	752
Change in unrealized gain (losses) still held	[2]	109	9
Trading securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers into Level 3		8
Transfers out of level 3		(1)	(1)
Trading securities | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		8	9
Gains (losses) in Earnings	[1]	0	0
Gains (losses) in OCI		0	0
Transfers into Level 3		0	0
Transfers out of level 3		0	0
Purchases		0	0
Sales		0	0
Issuances		0	0
Settlements		(1)	(1)
Ending Balance		7	8
Change in unrealized gain (losses) still held	[2]	0	0
Trading securities | Corporate bonds and other debt securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		71	1,033
Gains (losses) in Earnings	[1]	6	4
Gains (losses) in OCI		0	0
Transfers into Level 3		8	0
Transfers out of level 3		(1)	(1)
Purchases		65	232
Sales		(29)	(144)
Issuances		0	0
Settlements		(49)	(298)
Ending Balance		71	826
Change in unrealized gain (losses) still held	[2]	1	5
Trading securities | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		28	29
Gains (losses) in Earnings	[1]	1	1
Gains (losses) in OCI		0	0
Transfers into Level 3		0	0
Transfers out of level 3		0	0
Purchases		0	0
Sales		0	0
Issuances		0	0
Settlements		(3)	0
Ending Balance		26	30
Change in unrealized gain (losses) still held	[2]	(1)	1
Derivative financial instruments assets | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[5]	22	8
Gains (losses) in Earnings	[5]	24	(5)	[1]
Gains (losses) in OCI	[5]	0	0
Transfers into Level 3	[5]	0	0
Transfers out of level 3	[5]	0	0
Purchases	[5]	0	0
Sales	[5]	0	0
Issuances	[5]	0	0
Settlements	[5]	4	2
Ending Balance	[5]	50	5
Change in unrealized gain (losses) still held	[2],[5]	(27)	(5)
Derivative financial instruments assets | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[5]	32	23
Gains (losses) in Earnings	[1],[5]	7	(1)
Gains (losses) in OCI	[5]	0	0
Transfers into Level 3	[5]	0	0
Transfers out of level 3	[5]	0	0
Purchases	[5]	0	0
Sales	[5]	0	0
Issuances	[5]	0	0
Settlements	[5]	0	0
Ending Balance	[5]	39	22
Change in unrealized gain (losses) still held	[2],[5]	4	(2)
Derivative financial instruments assets | Equity-related contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[5]	(14)	(21)
Gains (losses) in Earnings	[1],[5]	(12)	(14)
Gains (losses) in OCI	[5]	0	0
Transfers into Level 3	[5]	0	0
Transfers out of level 3	[5]	0	0
Purchases	[5]	0	0
Sales	[5]	0	0
Issuances	[5]	0	0
Settlements	[5]	4	(4)
Ending Balance	[5]	(22)	(39)
Change in unrealized gain (losses) still held	[2],[5]	(129)	(22)
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	2
Gains (losses) in Earnings	[1],[5]	(2)	(1)
Gains (losses) in OCI	[5]	0	0
Transfers into Level 3	[5]	0	(1)
Transfers out of level 3	[5]	0	0
Purchases	[5]	0	0
Sales	[5]	0	0
Issuances	[5]	0	0
Settlements	[5]	(1)	1
Ending Balance	[5]	(2)	1
Change in unrealized gain (losses) still held	[2],[5]	(6)	1
Derivative financial instruments assets | Other contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[5]	0	0
Gains (losses) in Earnings	[5]	0	1	[1]
Gains (losses) in OCI	[5]	0	0
Transfers into Level 3	[5]	0	0
Transfers out of level 3	[5]	0	0
Purchases	[5]	0	0
Sales	[5]	0	0
Issuances	[5]	0	0
Settlements	[5]	0	0
Ending Balance	[5]	0	1
Change in unrealized gain (losses) still held	[2],[5]	0	0
Available-for-sale securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers out of level 3		(9)
Available-for-sale securities | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		18	23
Gains (losses) in Earnings	[6]	0	0
Gains (losses) in OCI	[4]	0	0
Transfers into Level 3		0	0
Transfers out of level 3		0	0
Purchases		0	0
Sales		0	0
Issuances		0	0
Settlements		(3)	(3)
Ending Balance		15	20
Change in unrealized gain (losses) still held	[2]	0	0
Available-for-sale securities | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		0	716
Gains (losses) in Earnings	[6]	0	0
Gains (losses) in OCI	[4]	0	0
Transfers into Level 3		0	0
Transfers out of level 3		0	0
Purchases		0	63
Sales		0	(6)
Issuances		0	0
Settlements		0	(7)
Ending Balance		0	766
Change in unrealized gain (losses) still held	[2]	0	0
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		315	365
Gains (losses) in Earnings	[6]	0	2
Gains (losses) in OCI	[4]	0	0
Transfers into Level 3		0	0
Transfers out of level 3		0	0
Purchases		3	8
Sales		0	0
Issuances		0	0
Settlements		(188)	(28)
Ending Balance		130	347
Change in unrealized gain (losses) still held	[2]	5	2
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		117	132
Gains (losses) in Earnings	[6]	0	0
Gains (losses) in OCI	[4]	1	(3)
Transfers into Level 3		0	0
Transfers out of level 3		(9)	0
Purchases		54	19
Sales		0	0
Issuances		0	0
Settlements		(2)	(31)
Ending Balance		161	117
Change in unrealized gain (losses) still held	[2]	0	0
Available-for-sale securities | Other investments
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		56	53
Gains (losses) in Earnings	[6]	3	(1)
Gains (losses) in OCI		0	0
Transfers into Level 3		0	0
Transfers out of level 3		0	0
Purchases		36	34
Sales		0	(1)
Issuances		0	0
Settlements		(31)	(32)
Ending Balance		64	53
Change in unrealized gain (losses) still held	[2]	¥ 0	¥ (2)
[1]Gains (losses) in Earnings are reported in Trading account gains (losses)-net, Foreign exchange gains (losses)-net or Other noninterest income (expenses).[2]Amounts represent total gains or losses recognized in earnings and OCI 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 September 30, 2021 and 2022. The amounts of unrealized gains (losses) in OCI are related to Available-for-sale securities and Long-term debt, which were ¥nil billion and ¥(5) billion, respectively, at September 30, 2021, and ¥5 billion and ¥6 billion, respectively, at September 30, 2022.[3]Gains (losses) in Earnings are reported in Other noninterest income (expenses).[4]Gains (losses) in OCI are reported in Other comprehensive income (loss).[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	6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Unrealized gains (losses) in OCI related to Available-for-sale securities	¥ 5
Unrealized gains (losses) in OCI related to Long-term debt	¥ 6	¥ 5

Fair Value (Quantitative Inform

Fair Value (Quantitative Information about Significant Unobservable Inputs Related to Material Classes of Level 3 Assets and Liabilities) (Detail) ¥ in Millions		Sep. 30, 2022 JPY (¥)	Mar. 31, 2022 JPY (¥)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt		¥ 2,736,380	¥ 2,756,062
Available For Sale And Trading Securities | Residential mortgage-backed securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		22,000	26,000
Available For Sale And Trading Securities | Corporate bonds and other debt securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		362,000	503,000
Derivative Financial Instruments | Interest rate contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments		50,000	22,000
Derivative Financial Instruments | Foreign exchange contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments		39,000	32,000
Derivative Financial Instruments | Equity-related contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments		(22,000)	(14,000)
Derivative Financial Instruments | Credit-related contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments		(2,000)	1,000
Derivative Financial Instruments | Other contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments		0	0
Long-term debt
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt		¥ 806,000	¥ 794,000
Minimum | Measurement Input, Prepayment Rate [Member] | Available For Sale And Trading Securities | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		0	0
Minimum | Measurement Input, Prepayment Rate [Member] | Available For Sale And Trading Securities | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[1]	26	6
Minimum | Measurement Input, Default Rate [Member] | Available For Sale And Trading Securities | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		0	0
Minimum | Measurement Input, Default Rate [Member] | Available For Sale And Trading Securities | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[1]	0	0
Minimum | Measurement Input, Default Rate [Member] | Derivative Financial Instruments | Credit-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[2]	0	0
Minimum | Measurement Input, Default Rate [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[2]	0	0
Minimum | Measurement Input Recovery Rate [Member] | Available For Sale And Trading Securities | 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] | Available For Sale And Trading Securities | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[1]	40	10
Minimum | Measurement Input, Discount Rate [Member] | Available For Sale And Trading Securities | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		0.0030	0.0030
Minimum | Measurement Input, Discount Rate [Member] | Available For Sale And Trading Securities | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[1]	0.0063	0.0035
Minimum | Measurement Input, Discount Rate1 [Member] | Available For Sale And Trading Securities | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[3]	0.0004	0.0004
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	[2]	23	23
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	[2]	23	23
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	[2]	5	11
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	[2]	5	11
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	[2]	41	41
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	[2]	41	41
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	[2]	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	[2]	25	25
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	[2]	(17)	(17)
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	[2]	10	13
Minimum | Measurement Input, Equity volatility [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[2]	10	9
Minimum | Measurement Input, Credit correlation [Member] | Derivative Financial Instruments | Credit-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[2]		43
Minimum | Measurement Input, Credit correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[2]	23	19
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	[2]	3	3
Minimum | Measurement Input, Equity correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[2]	3	3
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	[2]	0	0
Maximum | Measurement Input, Prepayment Rate [Member] | Available For Sale And Trading Securities | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		17	18
Maximum | Measurement Input, Prepayment Rate [Member] | Available For Sale And Trading Securities | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[1]	26	24
Maximum | Measurement Input, Default Rate [Member] | Available For Sale And Trading Securities | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		2	0
Maximum | Measurement Input, Default Rate [Member] | Available For Sale And Trading Securities | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[1]	0	60
Maximum | Measurement Input, Default Rate [Member] | Derivative Financial Instruments | Credit-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[2]	13	8
Maximum | Measurement Input, Default Rate [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[2]	13	8
Maximum | Measurement Input Recovery Rate [Member] | Available For Sale And Trading Securities | 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] | Available For Sale And Trading Securities | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[1]	40	40
Maximum | Measurement Input, Discount Rate [Member] | Available For Sale And Trading Securities | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		0.0167	0.0167
Maximum | Measurement Input, Discount Rate [Member] | Available For Sale And Trading Securities | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[1]	0.0127	0.0103
Maximum | Measurement Input, Discount Rate1 [Member] | Available For Sale And Trading Securities | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[3]	0.0441	0.0447
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	[2]	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	[2]	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	[2]	55	52
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	[2]	55	52
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	[2]	65	65
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	[2]	65	65
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	[2]	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	[2]	25	25
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	[2]	17	17
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	[2]	181	121
Maximum | Measurement Input, Equity volatility [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[2]	181	121
Maximum | Measurement Input, Credit correlation [Member] | Derivative Financial Instruments | Credit-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[2]		100
Maximum | Measurement Input, Credit correlation [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[2]	100	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	[2]	100	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	[2]	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	[2]	65	89
Weighted Average | Measurement Input, Prepayment Rate [Member] | Available For Sale And Trading Securities | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[4]	5	6
Weighted Average | Measurement Input, Prepayment Rate [Member] | Available For Sale And Trading Securities | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[1],[4]	26	24
Weighted Average | Measurement Input, Default Rate [Member] | Available For Sale And Trading Securities | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[4]	0	0
Weighted Average | Measurement Input, Default Rate [Member] | Available For Sale And Trading Securities | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[1],[4]	0	1
Weighted Average | Measurement Input, Default Rate [Member] | Derivative Financial Instruments | Credit-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[2],[4]	2	1
Weighted Average | Measurement Input, Default Rate [Member] | Long-term debt | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt	[2],[4]	3	1
Weighted Average | Measurement Input Recovery Rate [Member] | Available For Sale And Trading Securities | 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] | Available For Sale And Trading Securities | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[1],[4]	40	39
Weighted Average | Measurement Input, Discount Rate [Member] | Available For Sale And Trading Securities | Residential mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[4]	0.0051	0.0053
Weighted Average | Measurement Input, Discount Rate [Member] | Available For Sale And Trading Securities | Corporate bonds and other debt securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[1],[4]	0.0074	0.0047
Weighted Average | Measurement Input, Discount Rate1 [Member] | Available For Sale And Trading Securities | 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]	0.0026	0.0340
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	[2],[4]	75	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	[2],[4]	75	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	[2],[4]	38	31
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	[2],[4]	40	39
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	[2],[4]	53	53
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	[2],[4]	53	53
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	[2],[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	[2],[4]	25	25
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	[2],[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	[2],[4]	54	47
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	[2],[4]	37	34
Weighted Average | Measurement Input, Credit correlation [Member] | Derivative Financial Instruments | Credit-related contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[2],[4]		66
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	[2],[4]	65	64
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	[2],[4]	91	90
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	[2],[4]	90	90
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	[2],[4]	49	55
[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]Internal valuation model includes discounted cash flow models and the Black-Scholes option pricing model.[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	Sep. 30, 2022	Mar. 31, 2022
Assets:
Equity securities (without readily determinable fair values)	¥ 193,297	¥ 207,407
Fair Value, Measurements, Nonrecurring
Assets:
Loans	94,000	81,000
Loans held-for-sale	177,000	76,000
Equity securities (without readily determinable fair values)	1,000	4,000
Other investments	132,000
Total assets measured at fair value	404,000	161,000
Fair Value, Measurements, Nonrecurring | Aggregate cost
Assets:
Loans	166,000	128,000
Loans held-for-sale	192,000	77,000
Equity securities (without readily determinable fair values)	1,000	4,000
Other investments	161,000
Premises and equipment-net	1,000	13,000
Other assets		3,000
Total assets measured at fair value	521,000	225,000
Fair Value, Measurements, Nonrecurring | Level 1
Assets:
Other investments	132,000
Total assets measured at fair value	132,000
Fair Value, Measurements, Nonrecurring | Level 2
Assets:
Loans held-for-sale	51,000	27,000
Equity securities (without readily determinable fair values)	1,000	3,000
Total assets measured at fair value	52,000	30,000
Fair Value, Measurements, Nonrecurring | Level 3
Assets:
Loans	94,000	81,000
Loans held-for-sale	126,000	49,000
Equity securities (without readily determinable fair values)		1,000
Total assets measured at fair value	¥ 220,000	¥ 131,000

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		Sep. 30, 2022	Mar. 31, 2022
Financial liabilities:
Long-term debt		¥ 2,736,380	¥ 2,756,062
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		74,254,000	68,366,000
Investments		2,072,000	1,519,000
Loans, net of allowance	[1]	97,409,000	89,264,000
Financial liabilities:
Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions		57,249,000	58,054,000
Interest-bearing deposits		134,533,000	121,833,000
Due to trust accounts		350,000	390,000
Other short-term borrowings		3,593,000	7,567,000
Long-term debt		10,846,000	9,849,000
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		74,254,000	68,366,000
Investments		1,893,000	1,466,000
Loans, net of allowance	[1]	98,912,000	90,576,000
Financial liabilities:
Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions		57,249,000	58,054,000
Interest-bearing deposits		134,484,000	121,807,000
Due to trust accounts		350,000	390,000
Other short-term borrowings		3,593,000	7,567,000
Long-term debt		10,198,000	9,681,000
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		53,921,000	50,628,000
Investments		843,000	485,000
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		20,333,000	17,738,000
Investments		1,050,000	981,000
Financial liabilities:
Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions		57,249,000	58,054,000
Interest-bearing deposits		134,484,000	121,807,000
Due to trust accounts		350,000	390,000
Other short-term borrowings		3,593,000	7,567,000
Long-term debt		8,632,000	8,162,000
Estimated fair value | Level 3
Financial assets:
Loans, net of allowance	[1]	98,912,000	90,576,000
Financial liabilities:
Long-term debt		¥ 1,566,000	¥ 1,519,000
[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		Sep. 30, 2022	Mar. 31, 2022
Offsetting Financial Assets And Financial Liabilities [Line Items]
Derivative assets, Gross amounts recognized	[1]	¥ 18,030	¥ 9,723
Derivative assets, Gross amounts offset on the balance sheet	[1]	0	0
Derivative assets, Net amounts presented on the balance sheet	[1],[2],[3]	18,030	9,723
Derivative assets, Amounts not offset on the balance sheet, Financial instruments	[1],[4],[5]	(13,751)	(7,232)
Derivative assets, Amounts not offset on the balance sheet, Cash collateral	[1],[4]	(1,525)	(891)
Derivative assets, Net amounts	[1]	2,754	1,600
Receivables under resale agreements, Gross amounts recognized	[1]	14,872	12,751
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]	14,872	12,751
Receivables under resale agreements, Amounts not offset on the balance sheet, Financial instruments	[1],[4],[5]	(13,302)	(11,437)
Receivables under resale agreements, Amounts not offset on the balance sheet, Cash collateral	[1],[4]	0	0
Receivables under resale agreements, Net amounts	[1]	1,570	1,314
Receivables under securities borrowing transactions, Gross amounts recognized	[1]	2,355	2,339
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]	2,355	2,339
Receivables under securities borrowing transactions, Amounts not offset on the balance sheet, Financial instruments	[1],[4],[5]	(2,309)	(2,299)
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]	46	40
Financial assets, Gross amounts recognized, Total	[1]	35,257	24,813
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]	35,257	24,813
Financial assets, Amounts not offset on the balance sheet, Financial instruments, Total	[1],[4],[5]	(29,362)	(20,968)
Financial assets, Amounts not offset on the balance sheet, Cash collateral, Total	[1],[4]	(1,525)	(891)
Financial assets, Net amounts, Total	[1]	4,370	2,954
Derivative liabilities, Gross amounts recognized	[1]	18,294	9,770
Derivative liabilities, Gross amounts offset on the balance sheet	[1]	0	0
Derivative liabilities, Net amounts presented on the balance sheet	[1],[2],[3]	18,294	9,770
Derivative liabilities, Amounts not offset on the balance sheet, Financial instruments	[1],[4],[5]	(12,900)	(6,716)
Derivative liabilities, Amounts not offset on the balance sheet, Cash collateral	[1],[4]	(1,924)	(1,329)
Derivative liabilities, Net amounts	[1]	3,470	1,725
Payables under repurchase agreements, Gross amounts recognized	[1]	23,767	20,070
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]	23,767	20,070
Payables under repurchase agreements, Amounts not offset on the balance sheet, Financial instruments	[1],[4],[5]	(22,411)	(19,366)
Payables under repurchase agreements, Amounts not offset on the balance sheet, Cash collateral	[1],[4]	0	0
Payables under repurchase agreements, Net amounts	[1]	1,356	704
Payables under securities lending transactions, Gross amounts recognized	[1]	1,491	1,361
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]	1,491	1,361
Payables under securities lending transactions, Amounts not offset on the balance sheet, Financial instruments	[1],[4],[5]	(1,225)	(1,164)
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]	266	197
Financial liabilities, Gross amounts recognized, Total	[1]	43,552	31,201
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]	43,552	31,201
Financial liabilities, Amounts not offset on the balance sheet, Financial instruments, Total	[1],[4],[5]	(36,536)	(27,246)
Financial liabilities, Amounts not offset on the balance sheet, Cash collateral, Total	[1],[4]	(1,924)	(1,329)
Financial liabilities, Net amounts, Total	[1]	¥ 5,092	¥ 2,626
[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 ¥9,326 billion and ¥9,235 billion, respectively, at March 31, 2022, and ¥17,032 billion and ¥17,317 billion, respectively, at September 30, 2022.[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 ¥11,537 billion and ¥19,505 billion, respectively, at March 31, 2022, and ¥13,470 billion and ¥22,882 billion, respectively, at September 30, 2022.[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 ¥2,339 billion and ¥1,172 billion, respectively, at March 31, 2022, and ¥2,355 billion and ¥1,229 billion, respectively, at September 30, 2022.

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	Sep. 30, 2022	Mar. 31, 2022
Offsetting Financial Assets And Financial Liabilities [Line Items]
Receivables under resale agreement subject to enforceable master netting arrangements	¥ 13,470	¥ 11,537
Payables under repurchase agreement subject to enforceable master netting arrangements	22,882	19,505
Receivables under securities transaction borrowing subject to master netting arrangement	2,355	2,339
Payables under securities transaction lending subject to master netting arragement	1,229	1,172
Subject To Enforceable Master Netting Arragement [Member]
Offsetting Financial Assets And Financial Liabilities [Line Items]
Derivative assets subject to enforceable master netting arrangements	17,032	9,326
Derivative liabilities subject to enforceable master netting arrangements	¥ 17,317	¥ 9,235

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	Sep. 30, 2022	Mar. 31, 2022
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	¥ 23,767	¥ 20,070
Securities lending transactions	1,491	1,361
Total	25,258	21,431
Overnight and continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	3,016	7,011
Securities lending transactions	993	1,098
Total	4,009	8,109
Up to 30 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	13,156	10,621
Securities lending transactions	225	74
Total	13,381	10,695
31 to 90 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	5,782	1,340
Securities lending transactions	11	0
Total	5,793	1,340
Greater than 90 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	1,813	1,098
Securities lending transactions	262	189
Total	¥ 2,075	¥ 1,287

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	Sep. 30, 2022	Mar. 31, 2022
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	¥ 23,767	¥ 20,070
Securities lending transactions	1,491	1,361
Japanese government bonds and Japanese local government bonds
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	2,759	1,714
Securities lending transactions	210	217
Foreign government bonds and foreign agency mortgage-backed securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	19,019	17,445
Securities lending transactions	236	90
Commercial Paper and Corporate Bonds
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	336	271
Securities lending transactions	64	52
Equity Securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	1,441	609
Securities lending transactions	969	989
Other securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	212	31
Securities lending transactions	¥ 12	¥ 13

Business Segment Information -

Business Segment Information - Additional Information (Detail)	6 Months Ended
	Sep. 30, 2022 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		6 Months Ended
		Sep. 30, 2022	Sep. 30, 2021
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits + Net gains (losses) related to ETFs and others	[1],[2]	¥ 1,162.5	¥ 1,130.6
General and administrative expenses	[1],[3]	721.9	680.9
Equity in earnings (losses) of equity method investees—net	[1]	14.5	16.5
Amortization of goodwill and others	[1]	5.6	5.8
Net business profits (losses) + Net gains (losses) related to ETFs and others	[1],[4]	449.5	460.4
Fixed assets	[1],[5]	1,726	1,722.3
Operating Segments | Retail And Business Banking Company
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits + Net gains (losses) related to ETFs and others	[1],[2]	325.7	346.3
General and administrative expenses	[1],[3]	302.2	312.8
Equity in earnings (losses) of equity method investees—net	[1]	(0.9)	5.5
Amortization of goodwill and others	[1]	1	1.1
Net business profits (losses) + Net gains (losses) related to ETFs and others	[1],[4]	21.6	37.9
Fixed assets	[1],[5]	505.9	539.3
Operating Segments | Corporate And Institutional Company
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits + Net gains (losses) related to ETFs and others	[1],[2]	233.4	231.5
General and administrative expenses	[1],[3]	96.9	100.6
Equity in earnings (losses) of equity method investees—net	[1]	3.6	2.3
Amortization of goodwill and others	[1]	0	0
Net business profits (losses) + Net gains (losses) related to ETFs and others	[1],[4]	140.1	133.2
Fixed assets	[1],[5]	151.5	181.5
Operating Segments | Global Corporate Company
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits + Net gains (losses) related to ETFs and others	[1],[2]	317.1	286.6
General and administrative expenses	[1],[3]	152.2	142.1
Equity in earnings (losses) of equity method investees—net	[1]	11.6	8.9
Amortization of goodwill and others	[1]	0.2	0.2
Net business profits (losses) + Net gains (losses) related to ETFs and others	[1],[4]	176.3	153.2
Fixed assets	[1],[5]	167.8	167.2
Operating Segments | Global Markets Company
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits + Net gains (losses) related to ETFs and others	[1],[2]	232.5	258.3
General and administrative expenses	[1],[3]	126.1	111
Equity in earnings (losses) of equity method investees—net	[1]	0	0
Amortization of goodwill and others	[1]	0.4	0.4
Net business profits (losses) + Net gains (losses) related to ETFs and others	[1],[4]	106	146.9
Fixed assets	[1],[5]	85.8	96.1
Operating Segments | Asset Management Company
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits + Net gains (losses) related to ETFs and others	[1],[2]	27.8	29
General and administrative expenses	[1],[3]	17.1	16.2
Equity in earnings (losses) of equity method investees—net	[1]	0.2	0.9
Amortization of goodwill and others	[1]	3.5	3.6
Net business profits (losses) + Net gains (losses) related to ETFs and others	[1],[4]	7.4	10.1
Fixed assets	[1],[5]	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]	26	(21.1)
General and administrative expenses	[1],[3],[6]	27.4	(1.8)
Equity in earnings (losses) of equity method investees—net	[1],[6]	0	(1.1)
Amortization of goodwill and others	[1],[6]	0.5	0.5
Net business profits (losses) + Net gains (losses) related to ETFs and others	[1],[4],[6]	(1.9)	(20.9)
Fixed assets	[1],[5],[6]	¥ 815	¥ 738.2
[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 six months ended September 30, 2021 and 2022, net gains (losses) related to ETFs and others amounted to ¥21.8 billion and ¥8.7 billion, respectively, of which ¥22.9 billion and ¥7.6 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		6 Months Ended
		Sep. 30, 2022	Sep. 30, 2021
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits and net gains (losses) related to ETFs and others	[1],[2]	¥ 1,162.5	¥ 1,130.6
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		8.7	21.8
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		¥ 7.6	¥ 22.9
[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]“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 six months ended September 30, 2021 and 2022, net gains (losses) related to ETFs and others amounted to ¥21.8 billion and ¥8.7 billion, respectively, of which ¥22.9 billion and ¥7.6 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	6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
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	¥ 449.5	¥ 460.4
Adjustment to reconcile management reporting to Japanese GAAP:
General and administrative expenses: non-allocated gains (losses), net	21.1	19.2
Expenses related to portfolio problems (including reversal of (provision for) general reserve for losses on loans)	(55.4)	(59.9)
Gains on reversal of reserves for possible losses on loans, and others	4.9	10.2
Net gains (losses) related to stocks—Net gains (losses) related to ETFs and others	29.7	(6.9)
Net extraordinary gains (losses)	5.8	47.3
Others	(10.5)	(23.7)
Income before income tax expense under Japanese GAAP	445.1	446.6
Adjustment to reconcile Japanese GAAP to U.S. GAAP:
Derivative financial instruments and hedging activities	1.8	(47.9)
Investments	(842.1)	13.8
Loans	(14)	2.2
Allowances for credit losses	11.2	5
Premises and equipment	(43)	(34.9)
Land revaluation	1.4	1.6
Business combinations	(5.1)	3.4
Pension liabilities	(26.3)	(63.9)
Consolidation of variable interest entities	(53.6)	51.1
Foreign currency translation	(37.4)	2.4
Others	(0.6)	3.8
Income (loss) before income tax expense (benefit) under U.S. GAAP	¥ (562.6)	¥ 383.2

Business Segment Information _4

Business Segment Information (Reconciliation of Assets from Segment to Consolidated) (Detail) - JPY (¥) ¥ in Billions		6 Months Ended
		Sep. 30, 2022	Sep. 30, 2021
Schedule Of Assets By Segment [Line Items]
Fixed assets	[1],[2]	¥ 1,726	¥ 1,722.3
U.S. GAAP adjustments	[3]	651.9	763.6
Premises and equipment-net, Goodwill, Intangible assets, and right-of-use assets related to operating leases included in Other assets		¥ 2,377.9	¥ 2,485.9
[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.