Mizuho Financial (MFG) 20-F 5 Jul 19 2019 FY Annual report (foreign) Financial data

Document and Entity Information

Document and Entity Information	12 Months Ended
	Mar. 31, 2019shares
Document Type	20-F
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Registrant Name	MIZUHO FINANCIAL GROUP INC
Entity Central Index Key	0001335730
Current Fiscal Year End Date	--03-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Document Annual Report	true
Document Transition Report	false
Document Shell Company Report	false
Entity Shell Company	false
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding	25,385,978,807
American depositary shares
Trading Symbol	MFG
Security 12(b) Title	American depositary shares, each of which represents two shares of common stock
Security Exchange Name	NYSE
Common Stock
Security 12(b) Title	Common Stock, without par value
No Trading Symbol Flag	true

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - JPY (¥) ¥ in Millions	Mar. 31, 2019	Mar. 31, 2018
Assets:
Cash and due from banks	¥ 1,404,008	¥ 1,685,835
Interest-bearing deposits in other banks	44,268,731	46,485,086
Call loans and funds sold	763,453	720,461
Receivables under resale agreements	12,997,424	8,080,927
Receivables under securities borrowing transactions	2,578,134	4,408,508
Trading account assets	21,018,230	24,302,543
Investments (Note 4):
Available-for-sale securities (including assets pledged that secured parties are permitted to sell or repledge of ¥932,302 million in 2018 and ¥1,132,602 million in 2019)	18,133,916	23,665,628
Held-to-maturity securities (including assets pledged that secured parties are permitted to sell or repledge of ¥677,046 million in 2018 and ¥476,146 million in 2019)	1,604,104	2,517,551
Equity securities	4,034,609
Other investments	389,740	585,896
Loans (Notes 5 and 6)	82,799,943	83,514,644
Allowance for loan losses	(307,201)	(309,902)
Loans, net of allowance	82,492,742	83,204,742
Premises and equipment-net (Note 7)	1,900,952	2,116,184
Due from customers on acceptances	187,137	212,596
Accrued income	342,845	301,332
Goodwill (Note 8)	95,151	95,184
Intangible assets (Note 8)	74,240	84,447
Deferred tax assets	49,775	57,088
All other assets	5,276,004	5,731,634
Total	197,611,195	204,255,642
Liabilities and equity:
Noninterest-bearing deposits	23,844,639	21,068,569
Interest-bearing deposits	84,019,038	91,206,963
Noninterest-bearing deposits	1,793,803	2,257,350
Interest-bearing deposits	28,639,436	22,351,124
Due to trust accounts	312,347	3,992,544
Call money and funds purchased	2,841,932	2,105,294
Payables under repurchase agreements (Note 30)	14,640,369	16,656,930
Payables under securities lending transactions (Note 30)	1,797,737	1,832,870
Other short-term borrowings (Note 12)	1,994,826	1,688,018
Trading account liabilities	10,120,968	13,115,270
Bank acceptances outstanding	187,137	212,596
Income taxes payable	58,688	64,501
Deferred tax liabilities	108,120	306,203
Accrued expenses	288,556	232,885
Long-term debt (Notes 12 and 28)	11,529,400	12,955,230
All other liabilities (Note 13)	5,932,706	4,705,595
Total	188,109,702	194,751,942
Commitments and contingencies (Note 24)
MHFG shareholders' equity:
Common stock (Note 15)-no par value, authorized 48,000,000,000 shares in 2018 and 2019, and issued 25,389,644,945 shares in 2018, and 25,392,498,945 shares in 2019	5,829,657	5,826,383
Retained earnings	2,740,545	1,306,141
Accumulated other comprehensive income, net of tax (Note 17)	164,021	1,741,894
Less: Treasury stock, at cost-Common stock 24,829,446 shares in 2018, and 33,962,404 shares in 2019	(7,704)	(5,997)
Total MHFG shareholders' equity	8,726,519	8,868,421
Noncontrolling interests	774,974	635,279
Total equity	9,501,493	9,503,700
Total liabilities and equity	197,611,195	204,255,642
Consolidated VIEs
Assets:
Cash and due from banks	29,972	31,435
Interest-bearing deposits in other banks	31,676	95,048
Call loans and funds sold	115,199	5,312
Trading account assets	2,456,198	2,558,186
Investments (Note 4):
Investments	52,493	48,565
Loans, net of allowance	2,359,669	2,323,081
All other assets	1,003,133	806,141
Total	6,048,340	5,867,768
Liabilities and equity:
Payables under securities lending transactions (Note 30)	108,038
Other short-term borrowings (Note 12)	23,495	31,392
Trading account liabilities		22
Long-term debt (Notes 12 and 28)	344,526	419,649
All other liabilities (Note 13)	1,523,791	1,305,640
Total	¥ 1,999,850	¥ 1,756,703

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - JPY (¥) ¥ in Millions	Mar. 31, 2019	Mar. 31, 2018
Trading account assets, assets pledged that secured parties are permitted to sell or repledge	¥ 3,244,305	¥ 4,897,190
Available-for-sale securities, assets pledged that secured parties are permitted to sell or repledge	1,132,602	932,302
Held-to-maturity securities, assets pledged that secured parties are permitted to sell or repledge	476,146	677,046
Long-term debt, liabilities accounted for at fair value	¥ 2,433,294	¥ 1,955,636
Common stock, par value	¥ 0	¥ 0
Common stock, authorized	48,000,000,000	48,000,000,000
Common stock, issued	25,392,498,945	25,389,644,945
Treasury stock, shares	33,962,404	24,829,446

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Interest and dividend income:
Loans, including fees		¥ 1,381,553	¥ 1,109,776	¥ 1,009,094
Investments:
Interest		144,199	88,319	88,311
Dividends		88,289	86,066	77,343
Trading account assets		211,749	202,125	163,114
Call loans and funds sold		5,547	5,699	5,068
Receivables under resale agreements and securities borrowing transactions		254,862	149,197	91,453
Deposits in other banks		121,244	120,704	74,647
Total interest and dividend income		2,207,443	1,761,886	1,509,030
Interest expense:
Deposits		613,570	382,706	264,748
Trading account liabilities		49,660	41,514	21,399
Call money and funds purchased		11,121	5,031	3,173
Payables under repurchase agreements and securities lending transactions		382,045	243,569	120,578
Other short-term borrowings		33,313	16,166	12,175
Long-term debt		223,767	200,950	179,639
Total interest expense		1,313,476	889,936	601,712
Net interest income		893,967	871,950	907,318
Provision (credit) for loan losses (Note 6)		32,459	(126,362)	37,668
Net interest income after provision (credit) for loan losses		861,508	998,312	869,650
Noninterest income (Note 26):
Fee and commission income		853,290	865,711	825,963
Foreign exchange gains (losses)-net (Note 27)	[1],[2]	93,577	91,793	69,453
Trading account gains (losses)-net (Note 27)	[3]	328,841	236,982	(42,481)
Investment gains (losses)-net (Note 2):
Debt securities	[2]	(3,842)	7,757	59,517
Equity securities	[2]	(155,947)	289,400	273,753
Equity in earnings (losses) of equity method investees-net	[2]	29,172	24,342	26,785
Gains on disposal of premises and equipment	[2]	5,145	8,225	5,638
Other noninterest income	[3]	72,135	80,453	149,404
Total noninterest income		1,222,371	1,604,663	1,368,032
Noninterest expenses:
Salaries and employee benefits		682,645	688,481	663,166
General and administrative expenses		761,528	585,992	570,897
Occupancy expenses		207,814	191,592	194,955
Fee and commission expenses		189,722	189,187	177,006
Provision (credit) for losses on off-balance-sheet instruments		(8,969)	(30,244)	19,464
Other noninterest expenses		166,079	138,669	131,819
Total noninterest expenses		1,998,819	1,763,677	1,757,307
Income before income tax expense		85,060	839,298	480,375
Income tax expense (Note 20)		9,335	237,604	91,244
Net income		75,725	601,694	389,131
Less: Net income (loss) attributable to noncontrolling interests		(8,746)	24,086	26,691
Net income		¥ 84,471	¥ 577,608	¥ 362,440
Basic net income per common share		¥ 3.33	¥ 22.77	¥ 14.33
Diluted net income per common share		3.33	22.76	14.28
Dividends per share:
Class XI preferred stock				10
Common stock		¥ 7.50	¥ 7.50	¥ 7.50
[1]	Amounts include realized and unrealized gains and losses on both derivative instruments and nonderivative instruments. Amounts on derivative instruments include gains and losses on forward foreign exchange contracts and currency options. Amounts on nonderivative instruments include translation gains and losses related to foreign currency-denominated debt securities reported as Trading securities.
[2]	These amounts are revenues from contracts that do not meet the scope of ASC 606.
[3]	Part of these amounts are considered to be revenues from contracts that are within the scope of ASC 606.

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Net income	¥ 75,725	¥ 601,694	¥ 389,131
Other comprehensive income (loss), net of tax:
Net unrealized gains (losses) on available-for-sale securities, net of tax	(9,472)	97,428	51,957
Foreign currency translation adjustments, net of tax	(23,781)	(29,934)	(12,322)
Pension liability adjustments, net of tax	(24,168)	155,044	11,922
Own credit risk adjustments, net of tax	14,476
Change during fiscal year	(42,945)	222,538	51,557
Total comprehensive income	32,780	824,232	440,688
Less: Total comprehensive income (loss) attributable to noncontrolling interests	(8,960)	25,893	26,724
Total comprehensive income attributable to MHFG shareholders	¥ 41,740	¥ 798,339	¥ 413,964

CONSOLIDATED STATEMENTS OF EQUI

CONSOLIDATED STATEMENTS OF EQUITY - JPY (¥) ¥ in Millions	Total	Preferred stock	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income		Treasury Stock	Parent	Noncontrolling Interest
Balance at beginning of fiscal year at Apr. 01, 2016		¥ 98,924	¥ 5,703,144	¥ 746,785	¥ 1,469,308		¥ (3,610)		¥ 168,640
Cumulative effect of change in accounting principles at Apr. 01, 2016				(329)	330				(10,441)
Issuance of new shares of common stock due to conversion of preferred stock			98,924
Purchases of treasury stock							(1,903)
Conversion to common stock		¥ (98,924)
Balance at beginning of fiscal year, adjusted at Apr. 01, 2016				746,456	1,469,638				158,199
Issuance of new shares of common stock due to exercise of stock acquisition rights			969
Disposal of treasury stock							663
Transactions between the MHFG Group and the noncontrolling interest shareholders									328,692
Net income attributable to MHFG shareholders	¥ 362,440			362,440
Change during year	51,957				51,525
Performance-based stock compensation program			(655)
Cancellation of treasury stock							1
Dividends paid to noncontrolling interests									(2,914)
Dividends declared				(190,002)
Other			23,767
Net income (loss) attributable to noncontrolling interests	26,691								26,691
Other									32
Balance at end of fiscal year at Mar. 31, 2017	8,772,057		5,826,149	918,894	1,521,163		(4,849)	¥ 8,261,357	510,700
Purchases of treasury stock							(2,431)
Balance at beginning of fiscal year, adjusted at Mar. 31, 2017				918,894	1,521,163				510,700
Issuance of new shares of common stock due to exercise of stock acquisition rights			546
Disposal of treasury stock							1,283
Transactions between the MHFG Group and the noncontrolling interest shareholders									106,740
Net income attributable to MHFG shareholders	577,608			577,608
Change during year	97,428				220,731
Performance-based stock compensation program			(326)
Dividends paid to noncontrolling interests									(8,054)
Dividends declared				(190,361)
Other			14
Net income (loss) attributable to noncontrolling interests	24,086								24,086
Other									1,807
Balance at end of fiscal year at Mar. 31, 2018	9,503,700		5,826,383	1,306,141	1,741,894		(5,997)	8,868,421	635,279
Cumulative effect of change in accounting principles at Mar. 31, 2018				1,540,317	(1,535,142)	[1]			(616)
Purchases of treasury stock							(3,002)
Balance at beginning of fiscal year, adjusted at Mar. 31, 2018				2,846,458	206,752				634,663
Issuance of new shares of common stock due to exercise of stock acquisition rights			438
Disposal of treasury stock							1,295
Transactions between the MHFG Group and the noncontrolling interest shareholders									166,145
Net income attributable to MHFG shareholders	84,471			84,471
Change during year	(9,472)				(42,731)
Performance-based stock compensation program			(282)
Dividends paid to noncontrolling interests									(16,874)
Dividends declared				(190,384)
Other			3,118
Net income (loss) attributable to noncontrolling interests	(8,746)								(8,746)
Other									(214)
Balance at end of fiscal year at Mar. 31, 2019	¥ 9,501,493		¥ 5,829,657	¥ 2,740,545	¥ 164,021		¥ (7,704)	¥ 8,726,519	¥ 774,974
[1]	See Note 2 "Recently issued accounting pronouncements" for further details of the cumulative-effect adjustment for AOCI.

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income		¥ 75,725	¥ 601,694	¥ 389,131
Less: Net income (loss) attributable to noncontrolling interests		(8,746)	24,086	26,691
Net income attributable to MHFG shareholders		84,471	577,608	362,440
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization		355,164	179,158	171,202
Provision (credit) for loan losses		32,459	(126,362)	37,668
Investment losses (gains)-net		159,789	(297,157)	(333,270)
Equity in losses (earnings) of equity method investees-net	[1]	(29,172)	(24,342)	(26,785)
Foreign exchange losses (gains)-net		155,104	(251,613)	22,812
Deferred income tax expense (benefit)		(157,231)	60,011	(107,432)
Net change in trading account assets		2,776,764	992,084	4,867,508
Net change in trading account liabilities		(2,979,299)	(518,339)	(3,267,060)
Net change in loans held for sale		26,659	(54,530)	(5,574)
Net change in accrued income		(44,519)	(31,842)	7,087
Net change in accrued expenses		45,653	16,517	4,485
Other-net		235,177	(682,269)	(523,954)
Net cash provided by (used in) operating activities		661,019	(161,076)	1,209,127
Cash flows from investing activities:
Proceeds from sales of Available-for-sale securities	[2]	21,132,162	32,908,551	31,139,716
Proceeds from sales of Equity securities	[3]	3,973,437
Proceeds from maturities of Available-for-sale securities	[2]	15,673,340	13,819,828	7,100,083
Proceeds from maturities of Held-to-maturity securities		939,397	1,261,607	999,405
Purchases of Available-for-sale securities	[2]	(34,327,798)	(49,722,644)	(34,133,416)
Purchases of Held-to-maturity securities		(2,042)	(2,982)	(3,854)
Purchases of Equity securities	[3]	(3,429,923)
Proceeds from sales of loans		1,184,160	296,260	291,782
Net change in loans		(3,852,757)	(1,971,210)	(5,606,627)
Net change in call loans and funds sold, and receivables under resale agreements and securities borrowing transactions		(2,971,007)	54,786	(1,481,661)
Proceeds from sales of premises and equipment		7,812	22,302	12,059
Purchases of premises and equipment		(157,714)	(292,201)	(430,913)
Cash and cash equivalents acquired in business combination				1,095
Proceeds from sales of investments in subsidiaries (affecting the scope of consolidation)		220	948
Cash outflow from deconsolidation of a subsidiary	[4]	(4,943,059)
Net cash used in investing activities		(6,773,772)	(3,624,755)	(2,112,331)
Cash flows from financing activities:
Net change in deposits		3,065,826	6,083,800	14,005,565
Net change in call money and funds purchased, and payables under repurchase agreements and securities lending transactions		1,703,606	(67,508)	(771,368)
Net change in due to trust accounts		(59,373)	(130,544)	(344,217)
Net change in other short-term borrowings		270,560	257,774	(589,512)
Proceeds from issuance of long-term debt		1,659,412	1,956,007	4,496,041
Repayment of long-term debt		(3,241,799)	(3,310,804)	(4,734,010)
Proceeds from noncontrolling interests		219,187	76,894	3,323
Payments to noncontrolling interests		(579)	(12,949)	(1,696)
Proceeds from issuance of common stock		3	3	6
Proceeds from sales of treasury stock		953	1	1
Purchases of treasury stock		(2,124)	(1,611)	(1,435)
Dividends paid		(190,413)	(190,382)	(190,031)
Dividends paid to noncontrolling interests		(16,874)	(8,054)	(2,914)
Net cash provided by financing activities		3,408,385	4,652,627	11,869,753
Effect of exchange rate changes on cash and cash equivalents		206,186	(282,846)	(29,583)
Net increase (decrease) in cash and cash equivalents		(2,498,182)	583,950	10,936,966
Cash and cash equivalents at beginning of fiscal year		48,170,921	47,586,971	36,650,005
Cash and cash equivalents at end of fiscal year		45,672,739	48,170,921	47,586,971
Supplemental disclosure of cash flow information:
Interest paid		1,268,412	818,593	582,947
Income taxes paid		175,615	172,891	246,802
Noncash investing activities:
Transfer of loans into loans held-for-sale		2,728	35,166	18,739
Investment in capital leases		871	¥ 6,586	12,467
Noncash assets acquired and liabilities assumed at fair value in business combination (Note 3):
Noncash assets acquired at fair value				80,176
Noncash liabilities assumed at fair value				¥ 25,893
Deconsolidation of Trust & Custody Services Bank Ltd (Note 1):
Decrease in total assets		8,990,604
of which Cash and cash equivalents		4,943,059
Decrease in total liabilities		8,958,535
of which Due to trust accounts		3,620,825
Noncash assets acquired at fair value in an equity method investee	[4]	¥ 25,311
[1]	These amounts are revenues from contracts that do not meet the scope of ASC 606.
[2]	Proceeds from sales and maturities of Available-for-sale securities as well as Purchases of Available-for-sale securities include cash activity related to Other investments for the fiscal years ended March 31 2017 and 2018, the amounts of which are not significant.
[3]	Proceeds from sales of Equity securities as well as Purchases of Equity securities include cash activity related to Other investments for the fiscal year ended March 31 2019, the amounts of which are not significant.
[4]	The cash outflow was from deconsolidation of a subsidiary. See Note 1 "Basis of presentation and summary of significant accounting policies" for further details.

Basis of presentation and summa

Basis of presentation and summary of significant accounting policies	12 Months Ended
	Mar. 31, 2019
Basis of presentation and summary of significant accounting policies	1. Basis of presentation and summary of significant accounting policies Basis of presentation Mizuho Financial Group, Inc. (“MHFG”) is a joint stock corporation with limited liability under the laws of Japan. MHFG is a holding company for Mizuho Bank, Ltd. (“MHBK”), Mizuho Trust & Banking Co., Ltd. (“MHTB”), Mizuho Securities Co., Ltd. (“MHSC”), Asset Management One Co., Ltd. (“Asset Management One”), and other subsidiaries. MHFG, through its subsidiaries (“the MHFG Group”, or “the Group”), provides domestic and international financial services in Japan and other countries. The MHFG Group has introduced an in-house MHFG and its domestic subsidiaries as well as its foreign subsidiaries maintain their accounting records in accordance with the accounting standards of Japan and those standards of the countries in which they are domiciled. Certain adjustments and reclassifications have been incorporated in the accompanying consolidated financial statements to conform them to the accounting principles generally accepted in the United States of America (“U.S. GAAP”). The consolidated financial statements are stated in Japanese yen, the currency of the country in which MHFG is incorporated and principally operates. The accompanying consolidated financial statements include the accounts of MHFG and its subsidiaries. MHFG’s fiscal year ends on March 31 and the fiscal year of certain subsidiaries ends on December 31. When determining whether to consolidate investee entities, the MHFG Group performed 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 the 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. The amounts of asset management business fee income and expenses for the fiscal year ended March 31, 2017 have been reclassified from Other noninterest income and Other noninterest expenses to Fee and commission income and Fee and commission expenses, respectively, in order to conform to the current period’s presentation. Such reclassifications had no effect on net income or shareholders’ equity. In addition, certain other comparative amounts for the prior period have been reclassified in order to conform to the current period’s presentation. Use of estimates The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect reported amounts and related disclosures. Specific areas, among others, requiring the application of management’s estimates and judgment include assumptions pertaining to the allowance for loan losses, allowance for losses on off-balance-sheet Deconsolidation of TCSB In March 2018, Trust & Custody Services Bank, Ltd. (“TCSB”), MHFG’s former subsidiary, and Japan Trustee Services Bank, Ltd. (“JTSB”) entered into a management integration agreement. Based on the agreement, TCSB and JTSB incorporated a holding company, JTC Holdings, Ltd. (“JTC Holdings”) through joint share transfer on October 1, 2018, and became wholly-owned subsidiaries of JTC Holdings on that date. Starting October 1, 2018, MHFG has no longer consolidated TCSB, which had approximately ¥14 trillion and ¥9 trillion, respectively, in total assets as of March 31, 2018 and September 30, 2018. However, MHFG has maintained 27.0% of the voting equity interests in JTC Holdings and accounted for this investment using the equity method of accounting. There was no material effect from TCSB deconsolidation on the accompanying consolidated statement of income for the year ended March 31, 2019. Definition of cash and cash equivalents For purposes of the consolidated statements of cash flows, Cash and cash equivalents consists of Cash and due from banks and Interest-bearing deposits in other banks. Cash deposited with central banks that must be maintained to meet minimum regulatory requirements is classified as restricted cash and included in Cash and cash equivalents. See Note 9 “Pledged assets and collateral” for more information on restricted cash. The MHFG Group adopted ASU No.2016-18, No.2016-18”) No.2016-18, Translation of foreign currency financial statements and foreign currency transactions Financial statements of overseas entities are prepared using the functional currency of each entity and translated into Japanese yen for consolidation purposes. Assets and liabilities are translated using the fiscal-year-end Foreign currency translation gains and losses related to the financial statements of overseas entities of the MHFG Group, net of related income tax effects, are credited or charged directly to Foreign currency translation adjustments, a component of Accumulated other comprehensive income, net of tax (“AOCI”). The tax effects of gains and losses related to the foreign currency translation of financial statements of overseas entities are not recognized unless it is apparent that the temporary differences will reverse in the foreseeable future. Assets and liabilities of domestic and overseas entities denominated in foreign currencies are remeasured into the functional currency of the respective entity at the fiscal year-end Call loans and call money Call loans and call money represent lending/borrowing, primarily through the Japanese short-term money market, to/from other financial institutions such as banks, insurance companies, and securities brokerage houses. Repurchase and resale agreements, securities lending and borrowing and other secured financing transactions Securities sold under agreements to repurchase (“repurchase agreements”), securities purchased under agreements to resell (“resale agreements”) and securities lending and borrowing transactions are accounted for as secured financing or lending transactions when control over the underlying securities is not deemed to be surrendered by the transferor. Otherwise, they are recorded as sales of securities with related forward repurchase commitments or purchases of securities with related forward resale commitments in accordance with ASC 860, “Transfers and Servicing” (“ASC 860”). Under resale agreements, securities borrowing and certain derivatives transactions, the MHFG Group receives collateral in the form of securities. In many cases, the MHFG Group is permitted to sell or repledge the securities obtained as collateral. Disclosures in respect of such collateral are presented in Note 9 “Pledged assets and collateral”. With respect to repurchase agreements, securities lending, and certain derivative transactions, counterparties may have the right to sell or repledge securities that the MHFG Group has pledged as collateral. The MHFG Group separately discloses these pledged securities in the consolidated balance sheets. The MHFG Group monitors credit exposure arising from resale agreements, repurchase agreements, securities borrowing and securities lending transactions on a regular basis, and additional collateral is obtained from or returned to counterparties, as appropriate. Trading securities and trading securities sold, not yet purchased Trading securities consist of securities and money market instruments that are bought and held principally for the purpose of reselling in the near term with the objective of generating profits on short-term fluctuations in price. Trading securities sold, not yet purchased, are securities and money market instruments sold to third parties that the MHFG Group does not own and is obligated to purchase at a later date to cover the short position. Trading securities and trading securities sold, not yet purchased, are recorded on the trade date. Trading securities and trading securities sold, not yet purchased, are recorded at fair value in the consolidated balance sheets in Trading account assets and Trading account liabilities with realized and unrealized gains and losses recorded on a trade date basis in Trading account gains (losses)—net in the consolidated statements of income. Interest and dividends on trading securities, including securities sold, not yet purchased, are recorded in Interest and dividend income or Interest expense on an accrual basis. Investments Debt securities that the MHFG Group has both the positive intent and ability to hold to maturity are classified as Held-to-maturity Available-for-sale The credit component of an other-than-temporary impairment of a debt security is reported in Investment gains (losses)—net, and the noncredit component is reported in Other comprehensive income (loss). See Note 4 “Investments” for further discussion of impairment. Interest and dividends, as well as amortization of premiums and accretion of discounts, are reported in Interest and dividend income. Amortization of premiums and accretion of discounts on debt securities are recognized over their remaining maturities under the interest method. Gains and losses on disposition of investments are computed using the first-in first-out Other investments include marketable and non-marketable non-marketable Derivative financial instruments Derivative financial instruments are bought and held principally for the purpose of market making for customers, proprietary trading in order to generate trading revenues and fee income, and also to manage the MHFG Group’s exposure to interest rate, credit and market risks related to asset and liability management. Such derivative financial instruments include interest rate, foreign currency, equity, commodity and credit default swap agreements, options, caps and floors, and financial futures and forward contracts. Derivatives bought and held for trading purposes are recorded in the consolidated balance sheets at fair value in Trading account assets and Trading account liabilities. The fair values of derivatives in a gain position and a loss position are reported as Trading account assets and Trading account liabilities, respectively. Derivatives used for asset and liability management include contracts that qualify for hedge accounting under ASC 815, “Derivatives and Hedging” (“ASC 815”). To be eligible for hedge accounting, derivative instruments must be highly effective in achieving offsetting changes in fair values or variable cash flows of the hedged items attributable to the particular risk being hedged. All qualifying hedging derivatives are valued at fair value and included in Trading account assets or Trading account liabilities. Derivatives that do not qualify for hedge accounting under ASC 815 are treated as trading positions and are accounted for as such. The fair value amounts recognized for all derivatives are presented on a gross basis and not offset against the amounts recognized for the right to reclaim cash collateral or the obligation to return cash collateral under the master netting agreement with the same counterparty. The fair values of derivative financial instruments are determined based on quoted market prices or broker-dealer quotes, if available. If not available, the fair values are estimated using quoted market prices for similar instruments, option or binomial pricing models or a present value cash flow analysis, utilizing current observable market information, where available. In determining the fair values, the Group considers various factors such as exchange or over-the-counter Changes in the fair values of all derivatives are recorded in earnings, except for derivatives qualifying as net investment hedges under ASC 815 which are recorded in AOCI. The changes in the fair values of all derivatives relating to foreign currency exchange rates are included in Foreign exchange gains (losses)—net and Trading account gains (losses)—net. Other elements of the changes in the fair values, including interest rate, equity and credit related components, except these of certain credit derivatives hedging the credit risk in the corporate loan portfolio, are recognized in Trading account gains (losses)—net. The net gain (loss) resulting from changes in the fair values of certain credit derivatives where the Group purchases protection to mitigate its credit risk exposure related to its corporate loan portfolio is recorded in Other noninterest income (expenses). Certain financial and hybrid instruments often contain embedded derivative instruments that possess implicit or explicit contract terms similar to those of a derivative instrument. Such derivative instruments are required to be fair-valued separately from the host contracts if they meet the bifurcation criteria of an embedded derivative. Such criteria include that the entire instrument is not marked to market through earnings, the economic characteristics and risks of the embedded contract terms are not clearly and closely related to those of the host contract and the embedded contract terms would meet the definition of a derivative on a stand-alone basis. Loans Loans are generally carried at the principal amount adjusted for unearned income and deferred net nonrefundable loan fees and costs. Loan origination fees, net of certain direct origination costs, are deferred and recognized over the contractual life of the loan as an adjustment of yield using a method that approximates the interest method. Interest income on performing loans is accrued and credited to income as it is earned. Unearned income and discounts or premiums on purchased loans are deferred and recognized over the life of the loan using a method that approximates the interest method. Loans are considered impaired 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 impaired include delinquency status and the ability of the debtor to make payments of the principal and interest when due. Impaired loans include loans past due for 90 days or more and restructured loans that meet the definition of a troubled debt restructuring (“TDR”) in accordance with ASC 310, “Receivables” (“ASC 310”). All of the MHFG Group’s impaired loans are designated as nonaccrual loans and thus 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 collectibility 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. Impaired loans are restored to non-impaired non-impaired Loans that have been identified for sale are classified as loans held for sale within Other assets and are accounted for at the lower of cost or fair value on an individual loan basis. If management decides to retain certain loans held for sale for the foreseeable future or until maturity or payoff, such items are transferred to Loans at the lower of cost or fair value. Allowance and provision (credit) for loan losses The MHFG Group maintains an appropriate allowance for loan losses to absorb probable losses inherent in the loan portfolio and makes adjustments to such allowance through Provision (credit) for loan losses in the consolidated statements of income. Loan principal that management judges to be uncollectible, based on detailed loan reviews and a credit quality assessment, is charged off against the allowance for loan losses. In general, the MHFG Group charges off loans when the Group determines that the obligor should be classified as substantially bankrupt or bankrupt. See Note 5 “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 and other portfolio segments, the Group separately monitors the credit quality of each obligor without using time-based triggers. Subsequent recoveries of previously charged-off For the corporate portfolio segment, the credit quality review process and the credit rating process serve as the basis for determining the allowance for loan losses. 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 loan losses. MHFG Group’s accounting policies and the methodology used to estimate the allowance for loan losses for the other portfolio segment are equivalent to the policies and methodology used for the corporate portfolio segment. The allowance for loan losses is determined in accordance with ASC 310 and ASC 450, “Contingencies” (“ASC 450”). The MHFG Group measures the impairment of a loan when it is probable that the Group will be unable to collect all amounts due according to the contractual terms of the loan agreement, 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, or (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 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 formula allowance is applied to groups of loans that are collectively evaluated for impairment. The evaluation of the inherent loss in respect of these loans involves a high degree of uncertainty, subjectivity and judgment because probable loan losses are not easily identifiable or measurable. In determining the formula allowance, the MHFG Group therefore relies on a statistical analysis that incorporates loss rates based on its own historical loss experience and third-party data such as the number of corporate default cases which is updated once a year. In determining the allowance amount, the Group analyzes (1) the probability of default: (a) by using the most recently available data from April 2008 for the corporate portfolio segment, and the most recently available data for the past six years for the retail portfolio segment, in the case of normal obligors; and (b) by using the most recently available data from April 2002 for the corporate and retail portfolio segments, in the case of watch obligors; and (2) the loss given default by using the most recently available data for the past six years for the corporate and retail portfolio segments. As it pertains to TDR loans in the retail portfolio segment, which are subject to collective evaluation for impairment, the restructuring itself, as well as subsequent payment defaults, if any, are considered in determining obligor categories. The historical loss rate is adjusted, where appropriate, to reflect current factors, such as general economic and business conditions affecting the key lending areas of the MHFG Group, credit quality trends, specific industry conditions by portfolio segments, and recent loss experience in particular segments of the portfolio. When determining the length of the period to calculate the probability of default, the Group considers the uncertainty in the economic and business conditions. The estimation of the formula allowance is back-tested on a periodic basis by comparing the allowance with the actual results subsequent to the balance sheet date. Allowance and provision (credit) for losses on off-balance-sheet The MHFG Group maintains an allowance for losses on off-balance-sheet off-balance-sheet off-balance-sheet Premises and equipment Premises and equipment are stated at historical cost, and depreciation and amortization are recorded over the estimated useful lives of the assets, except for leasehold improvements, which are amortized over the shorter of the estimated useful lives of the assets or the lease term. Depreciation and amortization are principally computed in accordance with the straight-line method with respect to buildings and leasehold improvements and in accordance with the declining-balance method with respect to other premises and equipment. The useful lives of premises and equipment are as follows: Years Buildings 3 to 50 Equipment and furniture 2 to 20 Leasehold improvements 3 to 50 Regular repairs and maintenance costs that do not extend the estimated useful life of an asset are charged to expense as incurred. Upon sale or disposition of premises and equipment, the cost and related accumulated depreciation or amortization are removed from the accounts, and any gains or losses on disposal are included in Gains on disposal of premises and equipment or Occupancy expenses. Impairment of long-lived assets The MHFG Group’s long-lived assets that are held for use are reviewed periodically for events or changes in circumstances that indicate possible impairment. The Group’s impairment review is based on an undiscounted cash flow analysis of a group of assets, combined with associated liabilities, at the lowest level for which identifiable cash flows exist. Impairment occurs when the carrying value of the asset group exceeds the future undiscounted cash flows that the asset group is expected to generate. When impairment is identified, the future cash flows are then discounted to determine the estimated fair value of the asset group and an impairment charge is recorded for the difference between the carrying value and the estimated fair value of the asset group. The long-lived assets to be disposed of by sale are carried at the lower of the carrying amount or fair value, less estimated cost to sell. Software Internal and external costs incurred in connection with developing and obtaining software for internal use during the application development stage are capitalized. Such costs include salaries and benefits for employees directly involved with and who devote time to the project, to the extent such time is incurred directly on the internal use software project. The capitalization of software ceases when the software project has been substantially completed. The capitalized software is amortized on a straight-line basis over the estimated useful life, generally 5 to 10 years. Internal use software is reviewed for impairment whenever events or changes in circumstances indicate that its carrying amount may not be recoverable. Goodwill Goodwill represents the excess of the total fair value of the acquired company, which consists of the consideration transferred, the fair value of any interest in the acquiree already held by the acquirer and the fair value of any noncontrolling interest in the acquiree over the fair value of net identifiable assets acquired at the date of acquisition in a business combination. The MHFG Group accounts for goodwill in accordance with ASC 350, “Intangibles—Goodwill and Other” (“ASC 350”). Goodwill is recorded at a designated reporting unit level for the purpose of assessing impairment. Goodwill is not amortized but is tested for impairment at least annually or more often if events or circumstances indicate there may be impairment. For both the annual and interim tests, the Group has the option to either (a) perform a quantitative impairment test or (b) first perform a qualitative assessment to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount, in which case the Group would perform the quantitative test. An impairment loss is recorded to the extent the carrying amount of goodwill exceeds its estimated fair value. The estimated fair value of the reporting units is derived based on valuation techniques that the Group believes market participants would use for each of the reporting units. The Group generally determines the estimated fair value by utilizing a discounted cash flow methodology or methodologies that incorporate price-to-book Intangible assets Intangible assets having definite useful lives are amortized over their estimated useful lives on either a straight-line basis or the method that reflects the pattern in which the economic benefits of the intangible assets are consumed. Intangible assets acquired in connection with the merger of MHSC and Shinko Securities Co., Ltd. (“Shinko”) and the integration among asset management companies consist primarily of customer relationship intangibles, and are amortized over weighted-average amortization periods of 16 years and 16.9 years, respectively. See Note 3 “Business Combination” for further details of the integration among asset management companies. Intangible assets having indefinite useful lives are not amortized and are subject to impairment tests. An impairment loss is recorded to the extent that the carrying amount of the indefinite-lived intangible asset exceeds its estimated fair value. For intangible assets subject to amortization, an impairment loss is recorded if the carrying amount is not recoverable and exceeds its estimated fair value. Pension and other employee benefits MHFG and certain subsidiaries sponsor severance indemnities and pension plans, which provide defined benefits to retired employees. Periodic expense and accrued liabilities are computed based on the actuarial present value of benefits, net of investment returns expected from plan assets and their fair values at the balance sheet date. Net periodic expense is charged to Salaries and employee benefits. Net actuarial gains and losses that arise from differences between actual experience and assumptions are generally amortized over the average remaining service period of participating employees if they exceed the corridor, which is defined as the greater of 10% of plan assets or the projected benefit obligation. Stock-based compensation MHFG, MHBK, MHTB and MHSC have a position-based stock compensation program for Directors (“Stock Compensation I”) and a performance-based stock compensation program for Directors (“Stock Compensation II”). For both programs, the stock-based compensation cost is determined based on the fair value of MHFG’s common stock as of grant date. For Stock Compensation I and II, the liability related to the cash-based compensation cost is remeasured at each reporting date based on the fair value of MHFG’s common stock. For Stock Compensation II, the stock-based compensation costs are recognized evenly over the graded-vesting period, which is three years. For Stock Compensation I, as the program is effectively vested on the grant date, the stock-based compensation cost is recognized on the grant date. See Note 22 “Stock-based compensation” for further details of the stock options and the stock compensation programs. Long-term debt Premiums, discounts and issuance costs of long-term debt are amortized based on a method that approximates the interest method over the respective terms of the long-term debt. Obligations under guarantees The MHFG Group provides customers with a variety of guarantees and similar arrangements, including standby letters of credit, financial and performance guarantees, credit protection, and liquidity facilities. The MHFG Group recognizes guarantee fee income over the guarantee period. The MHFG Group receives such a guarantee fee at the inception of the guarantee or in installments and, in either case, the present value of the total fees approximates the fair value of the guarantee. Fair Value Measurements The MHFG Group carries certain of its financial assets and liabilities at fair value on a recurring basis. These financial assets and liabilities are primarily composed of trading account assets, trading account liabilities and available-for-sale non-recurring Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. In accordance with ASC 820, “Fair Value Measurement” (“ASC 820”), the Group classifies its financial assets and liabilities into the fair value hierarchy (Level 1, 2, and 3). See Note 28 “Fair value” for the detailed definition of each level. When determining fair value, the MHFG Group considers the principal or most advantageous market in which the Group would transact and considers assumptions that market participants would use when pricing the asset or liability. The Group maximizes the use of observable inputs and minimizes the use of unobservable inputs when measuring fair value. See Note 28 “Fair value” for descriptions of valuation methodologies used for its assets and liabilities by product. Fee and commission income The MHFG Group recognizes revenue from contracts with customers in an amount that reflects the consideration to which the Group expects to be entitled in exchange for transferring control of a promised service. The timing of revenue recognition is dependent on whether the Group satisfies a performance obligation by transferring control of the service to a customer over time or at a point in time. See Note 26 “Noninterest income” for further details of major components of Fee and commission income. Fee and commission income is presented exclusive of consumption taxes. Income taxes Income taxes are accounted for in accordance with ASC 740, “Income Taxes” (“ASC 740”). Deferred income taxes reflect the net tax effects of (1) temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the corresponding amounts used for income tax purposes, and (2) operating loss and tax credit carryforwards. A valuation allowance is recorded for any portion of the deferred tax assets unless it is more likely than not that the deferred tax assets will be realized. Deferred income tax benefit or expense is recognized for the changes in the net deferred tax asset or liability between periods. Earnings per common share Basic earnings per common share are computed by dividing net income attributable to MHFG common shareholders by the weighted average number of common shares outstanding during the fiscal year. Diluted earnings per common share reflect all dilutive potential common shares such as stock options and convertible preferred stock. See Note 19 “Earnings per common share” for the computation of basic and diluted earnings per common share.

Recently issued accounting pron

Recently issued accounting pronouncements	12 Months Ended
	Mar. 31, 2019
Recently issued accounting pronouncements	2. Recently issued accounting pronouncements Recently adopted accounting pronouncements In May 2014, the FASB issued ASU No.2014-09, No.2014-09”). No.2014-09 No.2014-09 In November 2014, the FASB issued ASU No.2014-16, No.2014-16”). No.2014-16 No.2014-16 In February 2015, the FASB issued ASU No.2015-02, No.2015-02”). 2a-7 No.2015-02 In April 2015, the FASB issued ASU No.2015-03, 835-30)—Simplifying No.2015-03”). No.2015-03 In May 2015, the FASB issued ASU No.2015-07, No.2015-07”). No.2015-07 No.2015-07 In January 2016, the FASB issued ASU No.2016-01, 825-10)—Recognition No.2016-01”). No.2016-01, Available-for-sale non-marketable No.2016-01, No.2016-01, In October 2016, the FASB issued ASU No.2016-16, No.2016-16”). No.2016-16 No. 2016-16 In May 2017, the FASB issued ASU No.2017-09, No.2017-09”). No.2017-09 No.2017-09 Accounting pronouncements issued but not yet effective as of March 31, 2019 In February 2016, the FASB issued ASU No.2016-02, No.2016-02”). right-of-use 2016-02 right-of-use In June 2016, the FASB issued ASU No.2016-13, No.2016-13”). available-for-sale No.2019-04, No.2019-05, No.2016-13, 2019-04, 2019-05 No.2016-13, 2019-04, 2019-05 In January 2017, the FASB issued ASU No.2017-04, No.2017-04”). No.2017-04 No.2017-04 In August 2017, the FASB issued ASU No.2017-12, No.2017-12 No.2017-12 In February 2018, the FASB issued ASU No.2018-02, No.2018-02”). No.2018-02 No.2018-02 In August 2018, the FASB issued ASU No.2018-13, No.2018-13”). No.2018-13 No.2018-13 In August 2018, the FASB issued ASU No.2018-14, 715-20)—Disclosure No.2018-14”). No.2018-14 No.2018-14 In October 2018, the FASB issued ASU No.2018-16, No.2018-16 No.2017-12, No.2018-16 No.2018-16 In October 2018, the FASB issued ASU No.2018-17, No.2018-17”). No.2018-17 No.2018-17

Business combination

Business combination	12 Months Ended
	Mar. 31, 2019
Business combination	3. Business combination Integration among asset management companies On October 1, 2016, DIAM Co., Ltd. (“DIAM”), MHTB, Mizuho Asset Management Co., Ltd. (“MHAM”) and Shinko Asset Management Co., Ltd. (“Shinko Asset Management”) (collectively, the “Integrating Companies”) integrated their asset management functions pursuant to an integration agreement signed on July 13, 2016. The integration was implemented through the following steps: (i) a merger between MHAM as surviving company and Shinko Asset Management as absorbed company; (ii) a company split between MHTB and MHAM (after the merger in (i) above) as successor company whereby rights and obligations attributed to Asset Management Division of MHTB were transferred to MHAM; and (iii) a merger between DIAM as surviving company and MHAM as absorbed company. After the integration, DIAM was renamed Asset Management One. As of September 30, 2016, MHAM was a wholly-owned subsidiary of MHFG and DIAM was an equity method affiliate of the MHFG Group which owned 50.0% of the voting equity interests. DIAM was a joint venture of MHFG and Dai-ichi (“Dai-ichi Dai-ichi Dai-ichi non-voting Based on the strong commitment of MHFG and Dai-ichi Dai-ichi The following table summarizes the consideration paid for DIAM and the amounts of the acquired assets and assumed liabilities recognized at the acquisition date, as well as the fair value at the acquisition date of the noncontrolling interest in DIAM. There were no material acquisition-related costs that were recognized separately from the acquisition of the assets and the assumption of the liabilities. At October 1, (in millions of yen) Consideration: Equity instruments (1,038,408 common shares of MHAM) 28,842 Fair value of total consideration transferred 28,842 Fair value of equity interests in DIAM held by MHFG before the business combination 72,106 100,948 Recognized amounts of identifiable assets acquired: Cash and due from banks 831 Interest-bearing deposits in other banks 12,873 Trading account assets 266 Investments 12,234 Premises and equipment-net 3,546 Accrued income 7,882 Intangible assets (Note) 53,037 Deferred tax assets 1,003 Other assets 2,208 Recognized amounts of identifiable liabilities assumed: Trading account liabilities 304 Income taxes payable 918 Deferred taxes liabilities 16,238 Accrued expenses 5,392 Other liabilities 3,041 Total identifiable net assets 67,987 Goodwill 76,225 Noncontrolling interest in DIAM 43,264 100,948 Note: Amount represents customer relationships subject to amortization, of which the weighted-average amortization period is 16.9 years. The fair value of the equity interests in DIAM held by MHFG before the business combination (¥72,106 million), the fair value of the 1,038,408 common shares of MHAM as the consideration paid for DIAM (¥28,842 million) and the fair value of the noncontrolling interest in DIAM (¥43,264 million) were determined with reference to an independent third-party appraisal by applying the income approach and the market approach. The income approach was based on the discounted future cash flows of DIAM and MHAM and the market approach was based on market values, earnings and revenues of public companies comparable to DIAM and MHAM. A discount for lack of control was not considered in determining the fair value of the noncontrolling interest, which is entirely held by Dai-Ichi Dai-Ichi On October 1, 2016, the MHFG Group recognized a gain of ¥56,226 million as a result of remeasuring to fair value its 50.0% of the voting equity interests in DIAM held before the business combination. The gain is included in Other noninterest income in the Group’s consolidated statement of income for the fiscal year ended March 31, 2017. In addition, the MHFG Group recognized an increase in Common stock of ¥23,829 million as a result of remeasuring to fair value its 30.0% of the voting equity interests in MHAM held before the business combination due to the change in the voting equity interests in MHAM on October 1, 2016. The revenue and earnings of Asset Management One since the acquisition date included in the Group’s consolidated statement of income for the fiscal year ended March 31, 2017 are not material. Other than the gain of ¥56,226 million described above, the revenue and earnings of the MHFG Group would not have differed significantly from those reported in the consolidated statements of income for the fiscal year ended March 31, 2017 if the business combination had occurred as of the beginning of the fiscal year.

Investments

Investments	12 Months Ended
	Mar. 31, 2019
Investments	4. Investments Available-for-sale held-to-maturity The amortized cost, gross unrealized gains and losses, and fair value of available-for-sale held-to-maturity Amortized cost Gross unrealized Gross unrealized Fair value (in millions of yen) 2018 Available-for-sale Debt securities: Japanese government bonds 13,334,619 7,332 9,656 13,332,295 Japanese local government bonds 236,711 2,903 280 239,334 U.S. Treasury bonds and federal agency securities 689,297 109 3,557 685,849 Other foreign government bonds 1,057,852 1,043 1,102 1,057,793 Agency mortgage-backed securities (1) 882,686 13,356 7,628 888,414 Residential mortgage-backed securities 117,870 1,264 281 118,853 Commercial mortgage-backed securities 437,115 4,132 323 440,924 Japanese corporate bonds and other debt securities (2) 1,950,947 40,290 1,410 1,989,827 Foreign corporate bonds and other debt securities (3) 879,506 1,927 2,082 879,351 Equity securities (marketable) (4) 1,595,106 2,449,173 11,291 4,032,988 Total 21,181,709 2,521,529 37,610 23,665,628 Held-to-maturity Debt securities: Japanese government bonds 1,959,910 24,472 — 1,984,382 Agency mortgage-backed securities (5) 557,641 — 20,177 537,464 Total 2,517,551 24,472 20,177 2,521,846 Amortized cost Gross unrealized Gross unrealized Fair value (in millions of yen) 2019 Available-for-sale Debt securities: Japanese government bonds 11,888,510 11,259 2,998 11,896,771 Japanese local government bonds 208,308 1,671 87 209,892 U.S. Treasury bonds and federal agency securities 1,008,903 644 231 1,009,316 Other foreign government bonds 1,341,564 758 455 1,341,867 Agency mortgage-backed securities (1) 530,540 14,524 593 544,471 Residential mortgage-backed securities 99,904 1,420 191 101,133 Commercial mortgage-backed securities 495,313 4,914 104 500,123 Japanese corporate bonds and other debt securities (2) 1,743,309 7,686 1,561 1,749,434 Foreign corporate bonds and other debt securities (3) 778,088 3,047 226 780,909 Equity securities (marketable) (4) — — — — Total 18,094,439 45,923 6,446 18,133,916 Held-to-maturity Debt securities: Japanese government bonds 1,119,899 19,907 — 1,139,806 Agency mortgage-backed securities (5) 484,205 — 14,423 469,782 Total 1,604,104 19,907 14,423 1,609,588 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 ¥742,565 million and ¥145,849 million, respectively, at March 31, 2018, and ¥517,330 million and ¥27,141 million, respectively, at March 31, 2019. All Japanese agency mortgage-backed securities are issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise. Foreign agency mortgage-backed securities primarily consist of Government National Mortgage Association (“Ginnie Mae”) securities, which are guaranteed by the United States government. (2) Other debt securities presented in this line primarily consist of Japanese negotiable certificates of deposit (“NCDs”), of which the total fair values were ¥106,101 million at March 31, 2018, and ¥6,725 million at March 31, 2019. (3) Other debt securities presented in this line primarily consist of Foreign NCDs and asset-backed securities (“ABS”), of which the total fair values were ¥313,164 million at March 31, 2018, and ¥246,503 million at March 31, 2019. (4) The MHFG Group adopted ASU No.2016-01 available-for-sale (5) All Agency mortgage-backed securities presented in this line are Ginnie Mae securities. Contractual maturities The amortized cost and fair value of available-for-sale held-to-maturity Amortized cost Due in one Due after one Due after five Due after Total (in millions of yen) Available-for-sale Debt securities: Japanese government bonds 7,839,925 2,326,357 1,461,333 260,895 11,888,510 Japanese local government bonds 7,229 118,677 77,336 5,066 208,308 U.S. Treasury bonds and federal agency securities 989,921 18,982 — — 1,008,903 Other foreign government bonds 1,106,386 235,178 — — 1,341,564 Agency mortgage-backed securities — — — 530,540 530,540 Residential mortgage-backed securities — — 4,656 95,248 99,904 Commercial mortgage-backed securities 9,501 175,819 282,518 27,475 495,313 Japanese corporate bonds and other debt securities 137,824 876,876 521,851 206,758 1,743,309 Foreign corporate bonds and other debt securities 443,476 291,299 40,544 2,769 778,088 Total 10,534,262 4,043,188 2,388,238 1,128,751 18,094,439 Held-to-maturity Debt securities: Japanese government bonds 639,984 379,837 100,078 — 1,119,899 Agency mortgage-backed securities — — — 484,205 484,205 Total 639,984 379,837 100,078 484,205 1,604,104 Fair value Due in one Due after one Due after five Due after Total (in millions of yen) Available-for-sale Debt securities: Japanese government bonds 7,840,638 2,329,473 1,465,030 261,630 11,896,771 Japanese local government bonds 7,263 119,115 78,275 5,239 209,892 U.S. Treasury bonds and federal agency securities 990,029 19,287 — — 1,009,316 Other foreign government bonds 1,106,543 235,324 — — 1,341,867 Agency mortgage-backed securities — — — 544,471 544,471 Residential mortgage-backed securities — — 4,656 96,477 101,133 Commercial mortgage-backed securities 9,518 177,237 285,849 27,519 500,123 Japanese corporate bonds and other debt securities 138,670 878,396 524,003 208,365 1,749,434 Foreign corporate bonds and other debt securities 443,626 293,831 40,683 2,769 780,909 Total 10,536,287 4,052,663 2,398,496 1,146,470 18,133,916 Held-to-maturity Debt securities: Japanese government bonds 640,928 395,085 103,793 — 1,139,806 Agency mortgage-backed securities — — — 469,782 469,782 Total 640,928 395,085 103,793 469,782 1,609,588 Other-than-temporary impairment The MHFG Group performs periodic reviews to identify impaired securities in accordance with ASC 320, “Investments—Debt Securities” (“ASC 320”). For debt securities, in the cases where the MHFG Group has the intent to sell a debt security or more likely than not will be required to sell a debt security before the recovery of its amortized cost basis, the full amount of an other-than-temporary impairment loss is recognized immediately through earnings. In other cases, the MHFG Group evaluates expected cash flows to be received and determines if a credit loss exists, and if so, the amount of an other-than-temporary impairment related to the credit loss is recognized in earnings, while the remaining decline in fair value is recognized in other comprehensive income, net of applicable taxes. Effective April 1, 2018, the available-for-sale No.2016-01, The following table shows the other-than-temporary impairment losses on available-for-sale held-to-maturity 2017 2018 2019 (in millions of yen) Available-for-sale Debt securities 138 1,015 213 Equity securities (Note) 12,029 3,080 — Total 12,167 4,095 213 Note: Effective April 1, 2018, the available-for-sale For the fiscal year ended March 31, 2019, the other-than-temporary impairment losses on debt securities were attributable to the decline in the fair value of certain Japanese corporate bonds in respect of which the MHFG Group determined credit losses existed. In accordance with ASC 320, the other-than-temporary impairment on these securities was recognized in earnings. The total other-than-temporary impairment met the criteria to be immediately recorded in earnings and no portion was recognized in other comprehensive income. Continuous unrealized loss position The following table shows the gross unrealized losses and fair value of available-for-sale held-to-maturity Less than 12 months 12 months or more Total Fair Gross Fair Gross Fair Gross (in millions of yen) 2018 Available-for-sale Debt securities: Japanese government bonds 8,052,820 3,716 2,868,078 5,940 10,920,898 9,656 Japanese local government bonds 28,827 139 58,998 141 87,825 280 U.S. Treasury bonds and federal agency securities 515,005 3,557 — — 515,005 3,557 Other foreign government bonds 419,648 1,030 68,359 72 488,007 1,102 Agency mortgage-backed securities (1) 45,434 1,116 188,326 6,512 233,760 7,628 Residential mortgage-backed securities 11,336 14 16,129 267 27,465 281 Commercial mortgage-backed securities 68,723 242 7,835 81 76,558 323 Japanese corporate bonds and other debt securities 563,831 933 403,069 477 966,900 1,410 Foreign corporate bonds and other debt securities 358,410 888 87,472 1,194 445,882 2,082 Equity securities (marketable) (2) 338,243 11,249 366 42 338,609 11,291 Total 10,402,277 22,884 3,698,632 14,726 14,100,909 37,610 Held-to-maturity Debt securities: Agency mortgage-backed securities (3) 30,589 766 506,875 19,411 537,464 20,177 Total 30,589 766 506,875 19,411 537,464 20,177 2019 Available-for-sale Debt securities: Japanese government bonds 2,296,536 1,441 1,332,688 1,557 3,629,224 2,998 Japanese local government bonds 9,752 32 38,873 55 48,625 87 U.S. Treasury bonds and federal agency securities 506,176 231 — — 506,176 231 Other foreign government bonds 438,771 321 26,782 134 465,553 455 Agency mortgage-backed securities (1) 466 2 37,706 591 38,172 593 Residential mortgage-backed securities — — 16,729 191 16,729 191 Commercial mortgage-backed securities 11,256 44 36,760 60 48,016 104 Japanese corporate bonds and other debt securities 417,825 924 440,937 637 858,762 1,561 Foreign corporate bonds and other debt securities 129,164 142 79,716 84 208,880 226 Equity securities (marketable) (2) — — — — — — Total 3,809,946 3,137 2,010,191 3,309 5,820,137 6,446 Held-to-maturity Debt securities: Agency mortgage-backed securities (3) — — 469,782 14,423 469,782 14,423 Total — — 469,782 14,423 469,782 14,423 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 ¥88,017 million and ¥145,743 million, respectively, at March 31, 2018, and ¥11,107 million and ¥27,065 million, respectively, at March 31, 2019. 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 Ginnie Mae securities, which are guaranteed by the United States government. (2) The MHFG Group adopted ASU No.2016-01 available-for-sale (3) All Agency mortgage-backed securities presented in this line are Ginnie Mae securities. At March 31, 2019, 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 MHFG 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 MHFG 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, the MHFG Group determined that the debt securities in an unrealized loss position were not considered other-than-temporarily impaired. Realized gains and losses The following table shows the realized gains and losses on sales of available-for-sale 2017 2018 2019 (Note) (in millions of yen) Gross realized gains 353,036 314,948 23,777 Gross realized losses (21,163 ) (41,044 ) (26,299 ) Net realized gains (losses) on sales of available-for-sale 331,873 273,904 (2,522 ) Note: Effective April 1, 2018, the available-for-sale Other investments The following table summarizes the composition of Other investments at March 31, 2018 and 2019: 2018 2019 (in millions of yen) Equity method investments 280,666 354,268 Investments held by consolidated investment companies 37,735 35,472 Other equity interests 267,495 — (Note) Total 585,896 389,740 Note: In connection with the adoption of ASU No.2016-01, 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 ¥152,445 million and ¥201,034 million, at March 31, 2018 and 2019, respectively. The aggregate market values of these marketable equity securities were ¥324,239 million and ¥308,137 million, respectively. The aggregate market values of these marketable equity securities include Orient Corporation, of which the MHFG Group’s proportionate share of the total outstanding common stock was 49.0% as of March 31, 2019. 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 Other equity interests Other equity interests primarily consist of non-marketable 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 without readily determinable fair values include non-marketable Net gains and losses The following table shows the details of the net gains and losses on Equity securities for the fiscal year ended March 31, 2019: 2019 (in millions of yen) Net gains and losses recognized during the period on equity securities (155,947 ) Less: Net gains and losses recognized during the period on equity securities sold during the period 34,034 Unrealized gains and losses recognized during the reporting period on equity securities still held at the reporting period (189,981 ) Equity securities without readily determinable fair values The following table shows the details of Equity securities without readily determinable fair values, for which the measurement alternative is used, for the fiscal year ended March 31, 2019: 2019 (in millions of yen) Carrying amounts at the end of the period 212,270 Downward adjustments and impairments: During the period 1,413 Cumulative 1,413 Upward adjustments: During the period 2,373 Cumulative 2,373 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

Loans

Loans	12 Months Ended
	Mar. 31, 2019
Loans	5. Loans The table below presents loans outstanding by domicile and industry of borrower at March 31, 2018 and 2019: 2018 2019 (in millions of yen) Domestic: Manufacturing 8,156,341 9,558,146 Construction and real estate 8,101,668 8,954,823 Services 5,024,018 5,113,386 Wholesale and retail 5,112,673 5,163,267 Transportation and communications 3,564,869 3,622,130 Banks and other financial institutions 4,471,423 4,303,231 Government and public institutions 8,882,125 2,358,904 Other industries (Note) 5,018,387 5,477,452 Individuals: Mortgage loans 9,445,286 8,950,216 Other 883,724 907,589 Total domestic 58,660,514 54,409,144 Foreign: Commercial and industrial 17,195,159 19,086,511 Banks and other financial institutions 7,465,140 9,126,392 Government and public institutions 302,891 296,872 Other 37,636 33,171 Total foreign 25,000,826 28,542,946 Total 83,661,340 82,952,090 Less: Unearned income and deferred loan fees—net 146,696 152,147 Total loans before allowance for loan losses 83,514,644 82,799,943 Note: Other industries of Domestic includes trade receivables and lease receivables of consolidated VIEs. Net losses on sales of loans were ¥919 million, ¥87 million and ¥2,018 million, including unrealized losses related to recording loans held for sale at the lower of cost or fair value for the fiscal years ended March 31, 2017, 2018 and 2019, respectively. The gains and losses on sales of loans are recorded in Other noninterest income and expenses, respectively. 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 incurring losses 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 table below presents the MHFG Group’s definition of obligor ratings used by MHBK and MHTB: Obligor category (1)(2) Obligor rating (3) 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 impaired. (2) The Group classifies loans to special attention, intensive control, substantially bankrupt and bankrupt obligors as impaired loans. (3) Equivalent obligor ratings are determined for the other portfolio segment. The table below presents credit quality information of loans based on the MHFG Group’s internal rating system at March 31, 2018 and 2019: Normal obligors Watch obligors excluding (1) Impaired Total Corporate Retail (2) Other (3) Corporate Retail (2) Other (3) (in millions of yen) 2018 Domestic: Manufacturing 7,705,495 77,947 23,343 197,465 9,775 246 142,070 8,156,341 Construction and real estate 7,317,972 541,778 13,332 172,287 15,466 — 40,833 8,101,668 Services 4,535,793 172,045 141,718 95,223 21,109 55 58,075 5,024,018 Wholesale and retail 4,636,236 177,965 17,305 121,832 27,975 476 130,884 5,112,673 Transportation and communications 3,414,781 76,532 1,774 35,339 8,916 — 27,527 3,564,869 Banks and other financial institutions 4,244,101 1,640 196,431 16,716 194 — 12,341 4,471,423 Government and public institutions 3,010,708 — 5,871,417 — — — — 8,882,125 Other industries (4) 2,716,502 3,536 2,170,442 2,708 259 121,201 3,739 5,018,387 Individuals 222,410 9,822,244 88,044 23,491 81,550 1,109 90,162 10,329,010 Total domestic 37,803,998 10,873,687 8,523,806 665,061 165,244 123,087 505,631 58,660,514 Foreign: Commercial and industrial 14,192,930 209 2,432,189 398,231 — 64,950 106,650 17,195,159 Banks and other financial institutions 6,949,036 — 487,978 28,126 — — — 7,465,140 Government and public institutions 301,072 — — — — — 1,819 302,891 Other 1,906 9,245 23,730 242 6 1,347 1,160 37,636 Total foreign 21,444,944 9,454 2,943,897 426,599 6 66,297 109,629 25,000,826 Total 59,248,942 10,883,141 11,467,703 1,091,660 165,250 189,384 615,260 83,661,340 2019 Domestic: Manufacturing 9,209,834 69,080 19,805 141,202 8,278 1,303 108,644 9,558,146 Construction and real estate 8,186,308 505,142 15,920 186,753 14,490 25 46,185 8,954,823 Services 4,761,724 165,643 3,281 90,578 18,586 1 73,573 5,113,386 Wholesale and retail 4,686,541 161,392 26,881 127,695 25,553 591 134,614 5,163,267 Transportation and communications 3,472,991 71,934 934 37,593 7,472 — 31,206 3,622,130 Banks and other financial institutions 4,262,125 1,534 72 28,881 319 — 10,300 4,303,231 Government and public institutions 2,358,899 5 — — — — — 2,358,904 Other industries (4) 3,131,072 2,450 2,323,197 7,725 421 3,633 8,954 5,477,452 Individuals 233,986 9,384,955 64,974 21,127 70,427 1,168 81,168 9,857,805 Total domestic 40,303,480 10,362,135 2,455,064 641,554 145,546 6,721 494,644 54,409,144 Foreign: Commercial and industrial 16,061,655 182 2,488,800 347,060 — 38,404 150,410 19,086,511 Banks and other financial institutions 8,623,103 — 492,831 10,458 — — — 9,126,392 Government and public institutions 296,870 — — — — — 2 296,872 Other 1,480 9,713 19,690 333 — 879 1,076 33,171 Total foreign 24,983,108 9,895 3,001,321 357,851 — 39,283 151,488 28,542,946 Total 65,286,588 10,372,030 5,456,385 999,405 145,546 46,004 646,132 82,952,090 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 impaired. (2) The obligor category classification is mainly based on past due status. (3) Non-impaired (4) Other industries of Domestic includes trade receivables and lease receivables of consolidated VIEs. Impaired loans The MHFG Group considers loans to be impaired when it is probable that the Group will be unable to collect all the scheduled payments of principal and interest when due according to the contractual terms of the loans. The Group classifies loans to special attention, intensive control, substantially bankrupt and bankrupt obligors as impaired loans, and all of the Group’s impaired loans are designated as nonaccrual loans. There are no loans that are ninety 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 impaired loans. The table below presents impaired loans information at March 31, 2018 and 2019: Recorded investment (1) Unpaid Related (3) Average Interest (4) Requiring an Not (2) Total (in millions of yen) 2018 Domestic: Manufacturing 135,083 6,987 142,070 146,857 45,750 218,899 1,869 Construction and real estate 31,557 9,276 40,833 48,752 4,411 49,926 516 Services 48,691 9,384 58,075 64,348 13,305 60,198 919 Wholesale and retail 119,463 11,421 130,884 139,556 42,798 139,333 1,842 Transportation and communications 25,019 2,508 27,527 28,480 6,862 25,672 370 Banks and other financial institutions 8,392 3,949 12,341 12,341 3,176 8,648 78 Other industries 3,650 89 3,739 3,869 3,563 4,537 53 Individuals 43,326 46,836 90,162 95,338 4,315 97,404 1,402 Total domestic 415,181 90,450 505,631 539,541 124,180 604,617 7,049 Foreign: Total foreign (5) 63,346 46,283 109,629 125,329 28,333 151,588 1,042 Total 478,527 136,733 615,260 664,870 152,513 756,205 8,091 2019 Domestic: Manufacturing 103,039 5,605 108,644 111,533 39,301 122,764 1,404 Construction and real estate 36,873 9,312 46,185 51,158 4,661 42,224 487 Services 64,021 9,552 73,573 79,736 16,311 67,679 1,058 Wholesale and retail 124,911 9,703 134,614 147,665 38,763 130,860 1,814 Transportation and communications 28,297 2,909 31,206 32,139 13,146 29,864 412 Banks and other financial institutions 6,473 3,827 10,300 10,300 1,327 10,671 109 Other industries 8,867 87 8,954 9,149 5,761 6,042 29 Individuals 37,488 43,680 81,168 88,331 2,630 86,082 1,326 Total domestic 409,969 84,675 494,644 530,011 121,900 496,186 6,639 Foreign: Total foreign (5) 119,079 32,409 151,488 164,984 47,345 113,559 1,518 Total 529,048 117,084 646,132 694,995 169,245 609,745 8,157 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 impaired loans. (2) These impaired loans do not require an allowance for loan losses because the MHFG Group has sufficient collateral to cover probable loan losses. (3) The allowance for loan losses on impaired loans includes the allowance for groups of loans which were collectively evaluated for impairment, in addition to the allowance for those loans that were individually evaluated for impairment. The total carrying amount of the groups of loans which were collectively evaluated for impairment at March 31, 2018 and 2019 was ¥245,809 million and ¥257,099 million, respectively. (4) Amounts represent the amount of interest income on impaired loans recognized on a cash basis and included in Interest income on loans in the consolidated statements of income. (5) The majority of Total foreign consist of Commercial and Industrial loans. The remaining balance of impaired loans that have been partially charged off, was ¥29,037 million and ¥25,097 million as of March 31, 2018 and 2019, respectively. 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 fiscal years ended March 31, 2018 and 2019: Loan forgiveness or debt to Interest rate Recorded (1 ) Charge-offs (in millions of yen) 2018 Domestic: Manufacturing — — 110,624 Construction and real estate — — 13,430 Services — — 40,774 Wholesale and retail — — 148,560 Transportation and communications — — 27,294 Banks and other financial institutions — — 8,529 Other industries — — 246 Individuals — — 14,960 Total domestic — — 364,417 Foreign: Total foreign (2) — — 44,010 Total — — 408,427 2019 Domestic: Manufacturing — — 134,544 Construction and real estate — — 39,254 Services — — 87,468 Wholesale and retail — — 167,299 Transportation and communications — — 33,991 Banks and other financial institutions — — 17,286 Other industries — — 120 Individuals — — 42,330 Total domestic — — 522,292 Foreign: Total foreign (2) 984 1,964 44,033 Total 984 1,964 566,325 Notes: (1) Amounts represent the book values of loans immediately after the restructurings. (2) The majority of Total foreign consist of Commercial and Industrial loans. Payment default is deemed to occur when the loan becomes three months past due or the obligor is downgraded to the category of substantially bankrupt or bankrupt. The following table presents payment defaults which occurred during the fiscal years ended March 31, 2018 and 2019 with respect to the loans modified as TDRs within the previous twelve months: Recorded investment 2018 2019 (in millions of yen) Domestic: Manufacturing 4,019 1,173 Construction and real estate 80 121 Services 4,469 1,335 Wholesale and retail 25,710 15,087 Transportation and communications 264 878 Banks and other financial institutions — 66 Other industries 130 1,650 Individuals 1,819 2,152 Total domestic 36,491 22,462 Foreign: Total foreign 4,588 5,418 Total 41,079 27,880 Age analysis of past due loans The table below presents an analysis of the age of the recorded investment in loans that are past due at March 31, 2018 and 2019: 30-59 days 60-89 days 90 days or Total past Current Total (in millions of yen) 2018 Domestic: Manufacturing 585 470 8,037 9,092 8,147,249 8,156,341 Construction and real estate 1,641 474 28,633 30,748 8,070,920 8,101,668 Services 1,977 1,142 5,051 8,170 5,015,848 5,024,018 Wholesale and retail 1,704 1,083 6,639 9,426 5,103,247 5,112,673 Transportation and communications 356 639 1,828 2,823 3,562,046 3,564,869 Banks and other financial institutions — 1,301 — 1,301 4,470,122 4,471,423 Government and public institutions — — — — 8,882,125 8,882,125 Other industries 33 12 37 82 5,018,305 5,018,387 Individuals 31,566 12,426 31,444 75,436 10,253,574 10,329,010 Total domestic 37,862 17,547 81,669 137,078 58,523,436 58,660,514 Foreign: Total foreign (Note) 897 450 41,316 42,663 24,958,163 25,000,826 Total 38,759 17,997 122,985 179,741 83,481,599 83,661,340 2019 Domestic: Manufacturing 2,210 513 7,036 9,759 9,548,387 9,558,146 Construction and real estate 1,010 1,054 31,092 33,156 8,921,667 8,954,823 Services 633 196 3,494 4,323 5,109,063 5,113,386 Wholesale and retail 1,614 1,415 7,868 10,897 5,152,370 5,163,267 Transportation and communications 363 256 2,119 2,738 3,619,392 3,622,130 Banks and other financial institutions 3 484 6 493 4,302,738 4,303,231 Government and public institutions — — — — 2,358,904 2,358,904 Other industries 2 — 57 59 5,477,393 5,477,452 Individuals 27,139 11,013 28,965 67,117 9,790,688 9,857,805 Total domestic 32,974 14,931 80,637 128,542 54,280,602 54,409,144 Foreign: Total foreign (Note) 668 211 26,316 27,195 28,515,751 28,542,946 Total 33,642 15,142 106,953 155,737 82,796,353 82,952,090 Note: The majority of Total foreign consist of Commercial and Industrial loans.

Allowance for loan losses

Allowance for loan losses	12 Months Ended
	Mar. 31, 2019
Allowance for loan losses	6. Allowance for loan losses In accordance with ASC 450, a formula-based allowance utilizing historical loss factors, after adjusting for existing economic conditions where appropriate, is applied to groups of non-homogeneous Changes in Allowance for loan losses by portfolio segment for the fiscal years ended March 31, 2017, 2018 and 2019 are shown below: Corporate Retail Other Total (in millions of yen) 2017 Balance at beginning of fiscal year 367,739 44,221 39,287 451,247 Provision (credit) for loan losses 45,059 (10,666 ) 3,275 37,668 Charge-offs (22,901 ) (1,754 ) (6,597 ) (31,252 ) Recoveries 18,320 5,122 2,158 25,600 Net charge-offs (4,581 ) 3,368 (4,439 ) (5,652 ) Others (Note) (890 ) — (2,700 ) (3,590 ) Balance at end of fiscal year 407,327 36,923 35,423 479,673 2018 Balance at beginning of fiscal year 407,327 36,923 35,423 479,673 Provision (credit) for loan losses (123,470 ) (7,427 ) 4,535 (126,362 ) Charge-offs (44,621 ) (2,118 ) (9,123 ) (55,862 ) Recoveries 12,924 814 1,482 15,220 Net charge-offs (31,697 ) (1,304 ) (7,641 ) (40,642 ) Others (Note) (3,088 ) — 321 (2,767 ) Balance at end of fiscal year 249,072 28,192 32,638 309,902 2019 Balance at beginning of fiscal year 249,072 28,192 32,638 309,902 Provision (credit) for loan losses 31,693 (2,658 ) 3,424 32,459 Charge-offs (39,728 ) (2,856 ) (4,940 ) (47,524 ) Recoveries 11,019 552 2,532 14,103 Net charge-offs (28,709 ) (2,304 ) (2,408 ) (33,421 ) Others (Note) 847 — (2,586 ) (1,739 ) Balance at end of fiscal year 252,903 23,230 31,068 307,201 Note: Others includes primarily foreign exchange translation. The table below presents Allowance for loan losses and loans outstanding by portfolio segment disaggregated on the basis of impairment method at March 31, 2018 and 2019: Corporate Retail Other Total (in millions of yen) 2018 Allowance for loan losses 249,072 28,192 32,638 309,902 of which individually evaluated for impairment 129,789 2,602 7,383 139,774 of which collectively evaluated for impairment 119,283 25,590 25,255 170,128 Loans (Note) 60,837,559 11,133,862 11,689,919 83,661,340 of which individually evaluated for impairment 593,053 21,364 61,023 675,440 of which collectively evaluated for impairment 60,244,506 11,112,498 11,628,896 82,985,900 2019 Allowance for loan losses 252,903 23,230 31,068 307,201 of which individually evaluated for impairment 139,472 2,122 8,933 150,527 of which collectively evaluated for impairment 113,431 21,108 22,135 156,674 Loans (Note) 66,804,088 10,596,994 5,551,008 82,952,090 of which individually evaluated for impairment 539,893 20,886 54,319 615,098 of which collectively evaluated for impairment 66,264,195 10,576,108 5,496,689 82,336,992 Note: Amounts represent loan balances before deducting unearned income and deferred loan fees.

Premises and equipment

Premises and equipment	12 Months Ended
	Mar. 31, 2019
Premises and equipment	7. Premises and equipment Premises and equipment at March 31, 2018 and 2019 consist of the following: 2018 2019 (in millions of yen) Land 566,040 563,032 Buildings 811,911 826,781 Equipment and furniture 484,102 472,186 Leasehold improvements 97,066 97,508 Construction in progress 25,849 37,174 Software 1,463,786 1,366,481 Total 3,448,754 3,363,162 Less: Accumulated depreciation and amortization 1,332,570 1,462,210 Premises and equipment—net 2,116,184 1,900,952 Depreciation and amortization expense for premises and equipment for the fiscal years ended March 31, 2017, 2018 and 2019 was ¥163,769 million, ¥169,346 million and ¥345,560 million, respectively. Premises and equipment under capital leases, which is primarily comprised of data processing equipment, amounted to ¥83,734 million and ¥83,935 million at March 31, 2018 and 2019, respectively. Accumulated depreciation and amortization on such premises and equipment at March 31, 2018 and 2019 amounted to ¥42,158 million and ¥57,193 million, respectively. Depreciation and amortization expense related to Software was reported in General and administrative expenses, and all other depreciation and amortization expense was reported in Occupancy expenses. The MHFG Group recognized impairment losses of ¥27,428 million on premises and equipment for the fiscal year ended March 31, 2019, of which ¥8,910 million was recorded in General and administrative expenses and ¥18,518 million was recorded in Occupancy expenses. Such losses included ¥15,761 million of impairment losses primarily on real estate recognized in Retail & Business Banking Company due to revisions of branch network strategy including schedule to close branches.

Goodwill and intangible assets

Goodwill and intangible assets	12 Months Ended
	Mar. 31, 2019
Goodwill and intangible assets	8. Goodwill and intangible assets Goodwill The changes in Goodwill during the fiscal years ended March 31, 2017, 2018 and 2019 are as follows: 2017 2018 2019 (in millions of yen) Balance at beginning of fiscal year 19,097 95,176 95,184 Goodwill acquired 76,225 (1) — — Foreign exchange translation (146 ) 8 (33 ) Balance at end of fiscal year 95,176 95,184 95,151 Gross amount of goodwill (2) 171,432 170,926 169,489 Accumulated impairment losses 76,256 75,742 74,338 Notes: (1) Goodwill acquired is entirely related to the acquisition of Asset Management One (see Note 3 “Business combination”). (2) Goodwill is recorded at a designated reporting unit level for the purpose of assessing impairment. Goodwill is not allocated to the reportable segments in Note 32 “Business segment information”. Intangible assets The table below presents the gross carrying amount, accumulated amortization and net carrying amount of intangible assets, at March 31, 2018 and 2019: 2018 2019 Gross Accumulated Net Gross Accumulated Net (in millions of yen) Intangible assets subject to amortization: Customer relationships (Note) 126,979 52,237 74,742 126,882 61,630 65,252 Other 1,847 1,341 506 1,698 1,412 286 Total 128,826 53,578 75,248 128,580 63,042 65,538 Intangible assets not subject to amortization: Total 9,199 — 9,199 8,702 — 8,702 Total 138,025 53,578 84,447 137,282 63,042 74,240 Note: Customer relationships were acquired in connection with the merger of MHSC and Shinko on May 7, 2009 and the integration among asset management companies on October 1, 2016, see Note 3 “Business combination” for further details of the integration among asset management companies. See Note 1 “Basis of presentation and summary of significant accounting policies” for further information. For the fiscal years ended March 31, 2017, 2018, and 2019, the MHFG Group recognized ¥7,433 million, ¥9,812 million, and ¥9,604 million, respectively, of amortization expense in respect of intangible assets, reported in Other noninterest expenses. The table below presents the estimated aggregate amortization expense in respect of intangible assets for the next five years: (in millions of yen) Fiscal year ending March 31: 2020 8,969 2021 8,237 2022 7,702 2023 7,184 2024 6,666

Pledged assets and collateral

Pledged assets and collateral	12 Months Ended
	Mar. 31, 2019
Pledged assets and collateral	9. Pledged assets and collateral The following amounts, by balance sheet classification, have been pledged as collateral for borrowings and for other purposes at March 31, 2018 and 2019: 2018 2019 (in billions of yen) Interest-bearing deposits in other banks 37 68 Trading account assets 5,611 4,137 Investments 6,500 6,076 Loans 5,229 4,055 Other assets 2,099 1,886 Total 19,476 16,222 The associated liabilities collateralized by the above assets at March 31, 2018 and 2019 are summarized below: 2018 2019 (in billions of yen) Deposits 256 386 Payables under repurchase agreements 5,518 3,435 Payables under securities lending transactions 1,193 1,675 Other short-term borrowings 441 519 Long-term debt 3,179 1,431 Total 10,587 7,446 The Bank of Japan (“the BOJ”) requires private depository institutions to maintain a certain amount of funds as reserves in current accounts with the BOJ, based on average deposit balances and certain other factors. There are similar reserve deposit requirements for foreign branches and subsidiaries engaged in banking businesses in foreign countries. At March 31, 2018 and 2019, the deposit amounts maintained with the BOJ and foreign central banks, which were included in Cash and due from banks and Interest-bearing deposits in other banks, were ¥45,325 billion and ¥43,552 billion, respectively. These balances included the reserve funds required to be maintained by the MHFG Group, which amounted to ¥1,589 billion and ¥1,583 billion at March 31, 2018 and 2019, respectively. At March 31, 2018 and 2019, the MHFG Group had received collateral that can be sold or repledged, with a fair value of ¥13,419 billion and ¥16,114 billion, respectively, of which ¥12,655 billion and ¥12,264 billion, respectively, was sold and repledged. Such collateral was primarily obtained in connection with resale or securities borrowing agreements, and was generally used as collateral for repurchase or securities lending agreements, or to cover short sales.

Deposits

Deposits	12 Months Ended
	Mar. 31, 2019
Deposits	10. Deposits The balances of time deposits and certificates of deposit issued by domestic offices in amounts of ¥10 million (approximately US$90 thousand at the Federal Reserve Bank of New York’s noon buying rate on March 31, 2019) or more and the balances of these deposits issued by foreign offices in amounts of US$100,000 or more at March 31, 2018 and 2019 are as follows: 2018 2019 (in millions of yen) Domestic offices: Time deposits 17,194,707 16,578,642 Certificates of deposit 5,778,430 5,643,303 Total 22,973,137 22,221,945 Foreign offices: Time deposits 13,426,554 17,606,520 Certificates of deposit 5,604,160 7,695,240 Total 19,030,714 25,301,760 The aggregate amount of demand deposits in overdraft status that have been reclassified as loan balances at March 31, 2018 and 2019 was ¥792 billion and ¥810 billion, respectively. The balance and remaining maturities of time deposits and certificates of deposit issued by domestic and foreign offices at March 31, 2019 are shown in the following table: Time Certificates of Total (in millions of yen) Domestic offices: Due in one year or less 21,240,581 5,492,603 26,733,184 Due after one year through two years 1,709,682 150,700 1,860,382 Due after two years through three years 1,387,191 — 1,387,191 Due after three years through four years 319,829 — 319,829 Due after four years through five years 371,921 — 371,921 Due after five years 245,455 — 245,455 Total 25,274,659 5,643,303 30,917,962 Foreign offices: Due in one year or less 17,525,778 7,468,492 24,994,270 Due after one year through two years 65,423 162,721 228,144 Due after two years through three years 3,902 64,055 67,957 Due after three years through four years 775 — 775 Due after four years through five years 11,369 — 11,369 Due after five years 11,122 — 11,122 Total 17,618,369 7,695,268 25,313,637 Total 42,893,028 13,338,571 56,231,599

Due to trust accounts

Due to trust accounts	12 Months Ended
	Mar. 31, 2019
Due to trust accounts	11. Due to trust accounts MHTB holds assets on behalf of its customers in an agent, fiduciary or trust capacity. Such trust account assets are not the MHFG Group’s proprietary assets and are managed and accounted for separately. However, the cash in individual trust accounts is often placed with MHTB for the customers’ short-term investment needs. These amounts which MHTB owes to the trust accounts are recorded as Due to trust accounts.

Short-term borrowings and long-

Short-term borrowings and long-term debt	12 Months Ended
	Mar. 31, 2019
Short-term borrowings and long-term debt	12. Short-term borrowings and long-term Short-term borrowings Short-term borrowings consist of Due to trust accounts, Call money and funds purchased, Payables under repurchase agreements and securities lending transactions, and Other short-term borrowings. Details of Other short-term borrowings at March 31, 2018 and 2019 are as follows: 2018 2019 (in millions of yen) Short-term notes issued by consolidated VIEs of asset-backed commercial paper programs (1) 27,985 22,339 Commercial paper and short-term notes issued by MHFG’s subsidiaries (1) (2) 1,044,591 1,274,382 Borrowings from the Bank of Japan 432,328 508,627 Other 183,114 189,478 Total 1,688,018 1,994,826 Notes: (1) Short-term notes are issued under the laws of Japan in the form of commercial paper. (2) The amounts of commercial paper and short-term notes issued by MHFG’s subsidiaries were ¥710,391 million and ¥334,200 million, respectively, at March 31, 2018, and ¥941,182 million and ¥333,200 million, respectively, at March 31, 2019. Long-term debt Long-term debt with original maturities of more than one year at March 31, 2018 and 2019 is comprised of the following: 2018 2019 (in millions of yen) Obligations under capital leases 36,010 25,020 Loan participation borrowings 89,353 142,838 Senior borrowings and bonds 9,184,075 7,503,032 Subordinated borrowings and bonds 3,645,792 3,858,510 Total 12,955,230 11,529,400 The following table presents the interest rates and maturities of senior borrowings and bonds, and subordinated borrowings and bonds: Interest rates (1) Maturities (2) 2018 2019 (%) (in millions of yen) Senior borrowings and bonds: fixed rate denominated in Japanese yen 0.00-8.10 Apr. 2019-Dec. 4,146,989 2,057,156 fixed rate denominated in U.S. dollars 0.00-5.39 Apr. 2019-Mar. 2,519,845 2,765,247 fixed rate denominated in other currencies 0.02-12.40 Apr. 2019-May. 2037 233,842 324,162 floating rate denominated in Japanese yen 0.00-25.00 Apr. 2019-Mar. 662,751 656,029 floating rate denominated in U.S. dollars 0.00-16.00 Apr. 2019-Jul. 1,469,248 1,493,617 floating rate denominated in other currencies 0.00-9.00 Apr. 2019-Mar. 151,400 206,821 Total 9,184,075 7,503,032 Subordinated borrowings and bonds: fixed rate denominated in Japanese yen 0.40-4.26 Jun. 2019-Perpetual 3,247,639 3,442,438 fixed rate denominated in U.S. dollars 4.30-4.70 Jul. 2022-Oct. 398,153 416,072 Total 3,645,792 3,858,510 Total 12,829,867 11,361,542 Notes: (1) The interest rates disclosed reflect the range of contractual rates in effect at March 31, 2019. (2) Maturity information disclosed is the range of maturities at March 31, 2019. (3) None of the long-term debt issuances above are convertible to common stock. (4) Certain debt agreements permit the MHFG Group to redeem the related debt, in whole or in part, prior to maturity at the MHFG Group’s option on terms specified in the respective agreements. The following is a summary of contractual maturities of long-term debt subsequent to March 31, 2019: (in millions of yen) Fiscal year ending March 31: 2020 1,401,583 2021 1,443,458 2022 1,319,030 2023 1,176,818 2024 508,821 2025 and thereafter 5,679,690 Total 11,529,400

Other assets and liabilities

Other assets and liabilities	12 Months Ended
	Mar. 31, 2019
Other assets and liabilities	13. Other assets and liabilities The following table sets forth the details of other assets and liabilities at March 31, 2018 and 2019: 2018 2019 (in millions of yen) Other assets: Accounts receivable: Receivables from brokers, dealers and customers for securities transactions (1) 1,578,952 1,517,235 Other 368,030 400,676 Collateral pledged: Collateral pledged for derivative transactions 981,390 856,439 Margins provided for futures contracts 142,156 159,747 Other 965,137 857,814 Prepaid pension cost 874,191 850,472 Security deposits 126,001 123,317 Loans held for sale 86,153 24,921 Other 609,624 485,383 Total 5,731,634 5,276,004 Other liabilities: Accounts payable: Payables to brokers, dealers and customers for securities transactions (1) 1,410,785 2,572,315 Other 455,789 442,776 Guaranteed trust principal (2) 761,685 809,450 Collateral accepted: Collateral accepted for derivative transactions 598,524 589,411 Margins accepted for futures contracts 325,038 339,863 Unearned income (3) 130,916 126,594 Other 1,022,858 1,052,297 Total 4,705,595 5,932,706 Notes: (1) Receivables from brokers, dealers and customers for securities transactions included ¥372,395 million and ¥555,938 million of such receivables of consolidated VIEs at March 31, 2018 and 2019, respectively. Payables to brokers, dealers and customers for securities transactions included ¥422,060 million and ¥620,766 million of such payables of consolidated VIEs at March 31, 2018 and 2019, respectively. (2) Guaranteed trust principal is the 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 25 “Variable interest entities and securitizations” for further discussion of the guaranteed principal money trusts. (3) Unearned income is primarily comprised of loan fees received from consumer loan customers when loans are made. This income is being deferred and recognized in earnings over the life of the loan.

Preferred stock

Preferred stock	12 Months Ended
	Mar. 31, 2019
Preferred stock	14. Preferred stock The composition of preferred stock at March 31, 2017, 2018 and 2019 is as follows: March 31, 2017 March 31, 2018 March 31, 2019 Class of stock Authorized Issued Authorized Issued Authorized Issued (number of shares) Class XI preferred stock 914,752,000 — — — — — Class XIV preferred stock 900,000,000 — 900,000,000 — 900,000,000 — Class XV preferred stock 900,000,000 — 900,000,000 — 900,000,000 — Class XVI preferred stock 1,500,000,000 — 1,500,000,000 — 1,500,000,000 — Holders or registered pledgees of preferred stock are entitled to receive annual dividends, and distribution of residual assets of MHFG as set out above at the liquidation value per share, prior to holders of common stock but pari passu among themselves. MHFG may pay up to one-half The following table shows the changes in the number of shares and the aggregate amount of preferred stock during the fiscal year ended March 31, 2017: 2017 (shares) (in millions of yen) Balance at beginning of fiscal year 914,752,000 914,752 Net change ( Note) (914,752,000 ) (914,752 ) Balance at end of fiscal year — — Note: In July 2016, all shares of the class XI preferred stock were converted into common stock and cancelled. There was no change in balance of the preferred stock in the fiscal years ended March 31, 2018 and 2019.

Common stock

Common stock	12 Months Ended
	Mar. 31, 2019
Common stock	15. Common stock The following table shows the changes in the number of issued shares of common stock during the fiscal years ended March 31, 2017, 2018 and 2019: 2017 2018 2019 (shares) Balance at beginning of fiscal year 25,030,525,657 25,386,307,945 25,389,644,945 Issuance of new shares of common stock due to conversion of class XI preferred stock 349,677,288 — — Issuance of new shares of common stock due to exercise of stock acquisition rights 6,105,000 3,337,000 2,854,000 Balance at end of fiscal year 25,386,307,945 25,389,644,945 25,392,498,945

Dividends

Dividends	12 Months Ended
	Mar. 31, 2019
Dividends	16. Dividends The amount available for dividends under Japan’s Companies Act is based on the amount recorded in MHFG’s non-consolidated period-end Pursuant to the Companies Act, in making a distribution of retained earnings, an entity must set aside in its legal reserve an amount equal to one-tenth one-quarter In addition to the provision that requires an appropriation for the legal reserve, the Companies Act and Japan’s Banking Act impose certain limitations on the amount available for dividends. Under the Companies Act, MHFG’s maximum amount available for dividends, at March 31, 2019, was ¥2,060,236 million, based on the amount recorded in MHFG’s general books of account under Japanese GAAP. Under the Banking Act and related regulations, MHFG has to meet the minimum capital adequacy requirements. Distributions of retained earnings, which are otherwise distributable to shareholders, are restricted in order to maintain the minimum Common Equity Tier 1 capital ratio of 4.5% for capital adequacy purposes under the rules in Basel III. See Note 18 “Regulatory matters” for further discussion of regulatory capital requirements. Payment of dividends on shares of common stock is also subject to the prior payment of dividends on shares of preferred stock, if any are outstanding.

Accumulated other comprehensive

Accumulated other comprehensive income	12 Months Ended
	Mar. 31, 2019
Accumulated other comprehensive income	17. Accumulated other comprehensive income Changes in each component of AOCI for the fiscal years ended March 31, 2017, 2018 and 2019 are as follows: 2017 2018 2019 (in millions of yen) AOCI, balance at beginning of fiscal year, previously reported 1,469,308 1,521,163 1,741,894 Cumulative effect of change in accounting principles 330 — (1,535,142 ) (1) AOCI, balance at beginning of fiscal year, adjusted 1,469,638 1,521,163 206,752 Net unrealized gains (losses) on available-for-sale Balance at beginning of fiscal year, previously reported 1,409,459 1,461,302 1,556,585 Cumulative effect of change in accounting principles (85 ) — (1,525,064 ) (1) Balance at beginning of fiscal year, adjusted 1,409,374 1,461,302 31,521 Unrealized holding gains (losses) during year 273,844 282,141 (11,358 ) Less: reclassification adjustments for losses (gains) included in net income (221,916 ) (186,858 ) 1,856 Change during year 51,928 95,283 (9,502 ) Balance at end of fiscal year 1,461,302 1,556,585 22,019 Foreign currency translation adjustments: Balance at beginning of fiscal year, previously reported 6,310 (5,535 ) (35,076 ) Cumulative effect of change in accounting principles 415 — — Balance at beginning of fiscal year, adjusted 6,725 (5,535 ) (35,076 ) Foreign currency translation adjustments during year (11,920 ) (26,936 ) (22,737 ) Less: reclassification adjustments for losses (gains) included in net income (340 ) (2,605 ) (745 ) Change during year (12,260 ) (29,541 ) (23,482 ) Balance at end of fiscal year (5,535 ) (35,076 ) (58,558 ) Pension liability adjustments: Balance at beginning of fiscal year 53,539 65,396 220,385 Unrealized gains (losses) during year 11,561 157,737 (17,243 ) Less: reclassification adjustments for losses (gains) included in net income 296 (2,748 ) (6,696 ) Change during year 11,857 154,989 (23,939 ) Balance at end of fiscal year 65,396 220,385 196,446 Own credit risk adjustments ( 2 ) Balance at beginning of fiscal year, previously reported — — — Cumulative effect of change in accounting principles — — (10,078 ) ( 1 ) Balance at beginning of fiscal year, adjusted — — (10,078 ) Unrealized gains (losses) during year — — 14,293 Less: reclassification adjustments for losses (gains) included in net income — — (101 ) Change during year — — 14,192 Balance at end of fiscal year — — 4,114 Total other comprehensive income (loss), net of tax attributable to MHFG shareholders 51,525 220,731 (42,731 ) AOCI, balance at end of fiscal year 1,521,163 1,741,894 164,021 Notes: (1) See Note 2 “Recently issued accounting pronouncements” for further details of the cumulative-effect adjustment for AOCI. (2) The MHFG Group adopted ASU No.2016-01 The following table shows the amounts reclassified out of AOCI into net income during the fiscal year ended March 31, 2019: Before tax (1) Tax effect (2) Net of tax before Net of tax attributable to (2) Net of tax attributable shareholders (in millions of yen) Amounts reclassified out of AOCI into net income: Affected line items in the consolidated statements of income: Net unrealized gains (losses) on available-for-sale (2,735 ) 889 (1,846 ) (10 ) (1,856 ) Investment gains (losses)—net Foreign currency translation adjustments 745 — 745 — 745 Investment gains (losses)—net Pension liability adjustments 9,068 (2,370 ) 6,698 (2 ) 6,696 Salaries and employee benefits Own credit risk adjustments 152 (47 ) 105 (4 ) 101 Other noninterest income (expenses) Total 7,230 (1,528 ) 5,702 (16 ) 5,686 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 and Net income, respectively.

Regulatory matters

Regulatory matters	12 Months Ended
	Mar. 31, 2019
Regulatory matters	18. Regulatory matters Regulatory capital requirements MHFG, MHBK, and MHTB are subject to regulatory capital requirements administered by the Financial Services Agency in accordance with the provisions of the Banking Act and related regulations. Certain foreign banking subsidiaries are subject to regulation and control by local supervisory authorities, including central banks. Failure to meet minimum capital requirements may initiate certain mandatory actions by regulators that, if undertaken, could have a direct material effect on the MHFG Group’s consolidated financial condition and results of operations. The capital adequacy guidelines applicable to Japanese banks and bank holding companies with international operations supervised by the Financial Services Agency closely follow the risk-adjusted approach proposed by the Bank for International Settlements and are intended to further strengthen the soundness and stability of Japanese banks. In December 2010, Basel Committee on Banking Supervision (“BCBS”) issued the Basel III rules text, which builds on the International Convergence of Capital Measurement and Capital Standards document (“Basel II”), to strengthen the regulation, supervision and risk management of the banking sector. Basel III text presents the details of global regulatory standards on bank capital adequacy and liquidity. The rules text sets out higher and better-quality capital, better risk coverage, the introduction of a leverage ratio as a backstop to the risk-based requirement, measures to promote the build-up of capital that can be drawn down in periods of stress, and the introduction of two global liquidity standards. The Financial Services Agency’s revisions to its capital adequacy guidelines became effective from March 31, 2013, which generally reflect the rules in the Basel III text that have been applied from January 1, 2013. There are three primary regulatory capital ratios used to assess capital adequacy: Common Equity Tier 1, Tier 1 and Total risk-based capital ratios. The ratios are comprised of Common Equity Tier 1 capital, Tier 1 capital (Common Equity Tier 1 capital and Additional Tier 1 capital) and total risk-based capital (Tier 1 and Tier 2 capital) divided by risk-weighted assets. Common Equity Tier 1 capital primarily consists of common stock, capital surplus, retained earnings and AOCI. Regulatory adjustments including certain intangible fixed assets, such as goodwill, and defined-benefit pension fund assets will be deducted from Common Equity Tier 1. Additional Tier 1 capital generally consists of Basel III compliant preferred securities and other capital that meets Tier 1 requirements under Basel II standards, net of regulatory adjustments. Tier 2 capital generally consists of Basel III compliant deferred obligations, such as subordinated debts, capital that meets Tier 2 requirements under Basel II standards, certain allowances for credit losses and noncontrolling interests in subsidiaries’ Tier 2 instruments. Under the revised guidelines, the minimum capital adequacy ratio is 8% on both a consolidated and non-consolidated Under Basel III, capital instruments that no longer qualify as Additional Tier 1 capital or Tier 2 capital are being phased out beginning March 2013 by increments of 10% until becoming fully effective in March 2022. The MHFG Group’s preferred securities (the amounts thereof included within Additional Tier 1 capital as of March 31, 2019 being ¥303.0 billion) and subordinated debt issued before March 2013 that are still outstanding (the amounts thereof included within Tier 2 capital as of March 31, 2019 being ¥506.1 billion) are subject to the phase-out In November 2015, the Financial Services Agency published the revised capital adequacy guidelines and related ordinances to introduce the capital buffer requirements under the Basel III rules for Japanese banks and bank holding companies with international operations, which include the capital conservation buffer, the countercyclical capital buffer and the additional loss absorbency requirements for global systemically important banks (“G-SIBs”) (“D-SIBs”). G-SIBs D-SIBs build-up G-SIB D-SIB, Leverage ratio The Leverage Ratio framework is critical and complementary to the risk-based capital framework that will help ensure broad and adequate capture of both on- off-balance Basel III’s leverage ratio is defined as the capital measure (numerator) divided by the exposure measure (denominator) and is expressed as a percentage. The capital measure for the leverage ratio is the Tier 1 capital of the risk-based capital framework, and the exposure measure is the sum of the on-balance off-balance In March 2019, the Financial Services Agency published the revised leverage ratio framework and the minimum leverage ratio is defined as 3% on both a consolidated and non-consolidated The capital requirements and regulatory adjustments are being phased in over a transitional period as follows (italicized percentages indicate those still in transition periods): March 2018 March 2019 March 2020 March 2021 March 2022 Minimum Common Equity Tier 1 capital 4.5 % 4.5 % 4.5 % 4.5 % 4.5 % Minimum Tier 1 capital 6.0 % 6.0 % 6.0 % 6.0 % 6.0 % Minimum total capital 8.0 % 8.0 % 8.0 % 8.0 % 8.0 % Phase out of recognition of capital instruments that no longer qualify as capital 40.0 % 30.0 % 20.0 % 10.0 % 0.0 % Capital conservation buffer 1.875 % 2.5 % 2.5 % 2.5 % 2.5 % Countercyclical capital buffer (1) 0.01 % 0.05 % 0.05 % 0.05 % 0.05 % Additional loss absorbency requirements for G-SIBs D-SIBs ( 2 ) 0.75 % 1.0 % 1.0 % 1.0 % 1.0 % Minimum Leverage Ratio 3.0 % 3.0 % 3.0 % 3.0 % 3.5 % (3) Notes: (1) Figures assume that the countercyclical capital buffer will continue to be 0.05% after March 2019. (2) Figures assume that the additional loss absorbency requirements applied to the Group as a G-SIB D-SIB (3) This figure includes a leverage ratio buffer required to be met at 50% of the additional loss absorbency requirements applied to the Group as a G-SIB under the finalized Basel III reforms. If the capital adequacy ratio and leverage ratio of a financial institution falls below the required level, the Financial Services Agency may, depending upon the extent of capital deterioration, take certain corrective action, including requiring the financial institution to submit an improvement plan to strengthen its capital base, reduce its total assets, restrict its business operations or other actions that could have a material effect on its financial condition and results of operations. Capital adequacy ratios and leverage ratios of MHFG, MHBK, and MHTB as of March 31, 2018 and 2019 calculated in accordance with Japanese GAAP and the guidelines established by the Financial Services Agency are set forth in the following table: 2018 2019 Amount Ratio Amount Ratio (in billions of yen, except percentages) Consolidated: MHFG: Common Equity Tier 1 capital: Required ( 1 ) 4,247 7.135 4,661 8.05 Actual 7,437 12.49 7,390 12.76 Tier 1 capital: Required ( 1 ) 5,140 8.635 5,529 9.55 Actual 9,192 15.44 9,232 15.94 Total risk-based capital: Required ( 1 ) 6,331 10.635 6,687 11.55 Actual 10,860 18.24 10,918 18.85 Leverage Ratio: Required / — / 3.00 Actual ( 2 ) / 4.28 / 4.42 MHBK: Common Equity Tier 1 capital: Required 2,400 4.50 2,388 4.50 Actual 6,584 12.34 6,690 12.60 Tier 1 capital: Required 3,200 6.00 3,184 6.00 Actual 8,330 15.61 8,527 16.06 Total risk-based capital: Required 4,267 8.00 4,246 8.00 Actual 9,881 18.52 10,098 19.02 Leverage Ratio: Required / — / 3.00 Actual ( 2 ) / 4.53 / 4.44 MHTB: Common Equity Tier 1 capital: Required 112 4.50 95 4.50 Actual 498 19.99 500 23.67 Tier 1 capital: Required 149 6.00 127 6.00 Actual 499 20.05 501 23.70 Total risk-based capital: Required 199 8.00 169 8.00 Actual 505 20.28 505 23.87 Leverage Ratio: Required / — / 3.00 Actual ( 2 ) / 7.03 / 6.55 Non-consolidated: MHBK: Common Equity Tier 1 capital: Required 2,312 4.50 2,272 4.50 Actual 6,330 12.32 6,363 12.60 Tier 1 capital: Required 3,082 6.00 3,029 6.00 Actual 8,081 15.73 8,199 16.23 Total risk-based capital: Required 4,109 8.00 4,039 8.00 Actual 9,619 18.72 9,757 19.32 Leverage Ratio: Required / — / 3.00 Actual ( 3 ) / — / 4.45 MHTB: Common Equity Tier 1 capital: Required 112 4.50 94 4.50 Actual 504 20.28 494 23.58 Tier 1 capital: Required 149 6.00 126 6.00 Actual 504 20.28 494 23.58 Total risk-based capital: Required 199 8.00 168 8.00 Actual 509 20.50 498 23.75 Leverage Ratio: Required / — / 3.00 Actual ( 3 ) / — / 6.53 Notes: (1) The required ratios disclosed above, at March 31, 2018 and 2019, include the transitional capital conservation buffer of 1.875% and 2.5%, respectively, the countercyclical capital buffer of 0.01% and 0.05%, respectively, and the transitional additional loss absorbency requirements for G-SIBs D-SIBs (2) The actual leverage ratios disclosed above, at March 31, 2018, are based on the Pillar 3 requirements. (3) MHBK and MHTB did not calculate the leverage ratios on non-consolidated MHFG’s securities subsidiary in Japan is also subject to the capital adequacy requirement under the Financial Instruments and Exchange Act. Under this requirement, securities firms must maintain a minimum capital adequacy ratio of 120% calculated as a percentage of capital accounts less certain assets, as calculated using Japanese GAAP figures, against amounts equivalent to market, counterparty, and basic risks. Specific guidelines are issued as a ministerial ordinance that details the definition of essential components of the capital ratios, including capital, disallowed assets and risks, and related measures. Failure to maintain a minimum capital ratio will trigger mandatory regulatory actions. A capital ratio of less than 140% will call for regulatory reporting and a capital ratio of less than 100% may lead to a temporary suspension of all or part of the business operations and further, to the cancellation of the license to act as a securities broker and dealer. Management believes, as of each latest balance sheet date, that MHFG, MHBK, MHTB, and their securities subsidiary in Japan and foreign banking subsidiaries were in compliance with all capital adequacy requirements to which they were subject.

Earnings per common share

Earnings per common share	12 Months Ended
	Mar. 31, 2019
Earnings per common share	19. Earnings per common share The following table sets forth the computation of basic and diluted earnings per common share for the fiscal years ended March 31, 2017, 2018 and 2019: 2017 2018 2019 (in millions of yen) Net income: Net income attributable to MHFG common shareholders 362,440 577,608 84,471 Effect of dilutive securities — — — Net income attributable to common shareholders after assumed conversions 362,440 577,608 84,471 2017 2018 2019 (thousands of shares) Shares: Weighted average common shares outstanding 25,285,899 25,366,345 25,362,376 Effect of dilutive securities: Convertible preferred stock (Note) 82,993 — — Stock options 11,410 7,586 4,522 Weighted average common shares after assumed conversions 25,380,302 25,373,931 25,366,898 2017 2018 2019 (in yen) Amounts per common share: Basic net income per common share 14.33 22.77 3.33 Diluted net income per common share 14.28 22.76 3.33 Note: The number of common shares after assumed conversion of the convertible preferred stock is based on the applicable conversion prices.

Income taxes

Income taxes	12 Months Ended
	Mar. 31, 2019
Income taxes	20. Income taxes Income tax expense The following table presents the components of Income tax expense for the fiscal years ended March 31, 2017, 2018 and 2019: 2017 2018 2019 (in millions of yen) Current: Domestic 130,164 130,573 116,695 Foreign 68,512 47,020 49,871 Total current tax expense 198,676 177,593 166,566 Deferred: Domestic (99,831 ) 58,078 (162,475 ) Foreign (7,601 ) 1,933 5,244 Total deferred tax expense (benefit) (107,432 ) 60,011 (157,231 ) Total income tax expense 91,244 237,604 9,335 The preceding table does not reflect the tax effects of items recorded directly in Equity for the fiscal years ended March 31, 2017, 2018 and 2019. The detailed amounts recorded directly in Equity are as follows: 2017 2018 2019 (in millions of yen) Net unrealized gains (losses) on available-for-sale Unrealized gains (losses) 112,467 123,186 (3,940 ) Less: reclassification adjustments (97,729 ) (82,828 ) 889 Total 14,738 40,358 (3,051 ) Pension liability adjustments: Unrealized gains (losses) 4,785 66,331 (6,558 ) Less: reclassification adjustments 178 190 (2,370 ) Total 4,963 66,521 (8,928 ) Own credit risk adjustments (Note) Unrealized gains (losses) — — 3,033 Less: reclassification adjustments — — (47 ) Total — — 2,986 Total tax effect before allocation to noncontrolling interests 19,701 106,879 (8,993 ) Note: The MHFG Group adopted ASU No.2016-01 Reconciliation of Income tax expense The following table shows a reconciliation of Income tax expense at the effective statutory tax rate to the actual income tax expense for the fiscal years ended March 31, 2017, 2018 and 2019: 2017 2018 2019 (in millions of yen, except tax rates) Income before income tax expense 480,375 839,298 85,060 Effective statutory tax rate 30.86 % 30.86 % 30.62 % Income tax calculated at the statutory tax rate 148,244 259,007 26,045 Income not subject to tax (7,521 ) (9,312 ) (8,861 ) Expenses not deductible for tax purposes 1,483 1,421 1,389 Tax rate differentials of subsidiaries (2,165 ) (2,696 ) (3,522 ) Change in valuation allowance 112,781 (1) (9,102 ) (2,444 ) Change in undistributed earnings of subsidiaries 5,217 (1,972 ) (21,347 ) (3) Change in net operating loss carryforwards resulting from intercompany capital transactions 647 — — Effect of enacted change in tax rates — 6,863 (2) (11 ) Reversal of outside basis differences (159,119 ) (1) — — Change in unrecognized tax benefits — — 9,420 Other (8,323 ) (6,605 ) 8,666 Income tax expense 91,244 237,604 9,335 Notes: (1) These amounts for the fiscal year ended March 31, 2017 represent mainly the reversal of an outside basis difference related to certain foreign subsidiaries due to their organizational restructuring and the related increase in the valuation allowance. (2) On December 22, 2017, the President of the United States signed into law the Tax Cuts and Jobs Act, which includes a reduction in the U.S. federal corporate income tax rate from 35% to 21%. The decrease in the Group’s balance of net deferred tax assets, reflecting such tax rate reductions, was recognized as an increase to Income tax expense in the fiscal year ended March 31, 2018. The MHFG Group has completed its analysis and accounting under Staff Accounting Bulletin No. 118 for the effects of the Act. (3) In the fiscal year ended March 31, 2019, the MHFG Group derecognized majority of deferred tax liabilities for undistributed earnings of foreign subsidiaries because the Group has intent and ability to reinvest those earnings indefinitely in certain foreign subsidiaries. Deferred tax assets and liabilities The components of net deferred tax assets (liabilities) at March 31, 2018 and 2019 are as follows: 2018 2019 (in millions of yen) Deferred tax assets: Allowance for loan losses 126,977 122,585 Premises and equipment 4,896 73,944 Derivative financial instruments 53,336 48,487 Investments 453,880 — Trading securities 1,988 — Net operating loss carryforwards (Note) 178,256 167,755 Other 204,005 216,568 1,023,338 629,339 Valuation allowance (Note) (163,358 ) (158,581 ) Deferred tax assets, net of valuation allowance 859,980 470,758 Deferred tax liabilities: Prepaid pension cost and accrued pension liabilities 255,239 247,694 Investments — 198,495 Available-for-sale 764,497 12,426 Trading securities — 9,158 Other 89,359 61,330 Deferred tax liabilities 1,109,095 529,103 Net deferred tax assets (liabilities) (249,115 ) (58,345 ) Note: The amount includes ¥110,729 million and ¥107,246 million related to MHSC’s net operating loss carryforwards resulting mainly from the organizational restructuring of certain foreign subsidiaries as of March 31, 2018 and 2019, respectively. The tax effect of the net operating loss carryforwards is substantially offset by ¥86,189 million and ¥88,294 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income. Deferred tax assets and deferred tax liabilities within the same tax jurisdiction have been netted for presentation purposes in the consolidated balance sheets. As of March 31, 2019, the accumulated amount of undistributed earnings that will be indefinitely reinvested and the unrecognized deferred tax liabilities related to such subsidiaries are approximately ¥186 billion and ¥17 billion, respectively. The following table and accompanying footnotes provide a breakdown of deferred tax assets and the valuation allowance recognized in respect of net operating loss carryforwards by tax jurisdiction and by year of expiration as of March 31, 2018 and 2019: Deferred tax assets Valuation allowance Deferred tax assets, net of valuation allowance (in billions of yen) 2018 Japan (1) 117 (88 ) 29 The United States 10 (1 ) 9 The United Kingdom (2) 48 (48 ) — Others 3 (2 ) 1 Total 178 (139 ) 39 2019 Japan (3) 111 (92 ) 19 The United States 8 — 8 The United Kingdom (2) 46 (46 ) — Others 3 (2 ) 1 Total 168 (140 ) 28 Notes: (1) ¥111 billion of the Japan deferred tax assets of ¥117 billion is related to MHSC, which is substantially offset by a valuation allowance, and will expire during the fiscal year ending March 31, 2026. (2) The United Kingdom net operating loss carryforwards may be carried forward indefinitely for tax purposes. (3) ¥107 billion of the Japan deferred tax assets of ¥111 billion is related to MHSC, which is substantially offset by a valuation allowance, and will expire during the fiscal year ending March 31, 2026. Determination of valuation allowance In accordance with ASC 740, when the MHFG Group determines whether and to what extent a valuation allowance is needed, the Group considers all available evidence, both positive and negative, to estimate future taxable income. In this regard, the Group considers reversals of existing taxable temporary differences, projected future taxable income (exclusive of reversals of existing temporary differences) and qualifying tax-planning available-for-sale tax-planning available-for-sale Positive evidence includes the Group’s results of operations for the current and preceding years on an overall consolidated basis and for most of the principal subsidiaries. In particular, the strong results of operations in recent years of MHFG’s principal banking subsidiaries in Japan represent positive evidence that can be objectively verified. Negative evidence includes the existence of significant amounts of net operating loss carryforwards or cumulative losses recorded at certain entities, and the expiration of unused net operating loss carryforwards in recent years. A valuation allowance is recorded against deferred tax assets as of the balance sheet date to the extent the Group estimates it is more likely than not that sufficient future taxable income is not available to realize such deferred tax assets. As the Group does not apply a consolidated taxation system, with a few exceptions of certain subsidiaries, deferred tax assets and liabilities are calculated separately for each legal entity. Therefore, changes in the valuation allowance are primarily due to changes in deductible temporary differences, net operating loss carryforwards and the estimated availability of future taxable income sources of each entity. In general, a valuation allowance is recognized against deferred tax assets related to entities that have accumulated significant net operating loss carryforwards. As of March 31, 2019, the Group’s valuation allowance was primarily related to entities in Japan, the United States and the United Kingdom. The valuation allowance was partially recognized in Japan and in the United States, while the valuation allowance was fully recognized in the United Kingdom. The Group determined whether cumulative losses were recognized by aggregating pretax results for the recent three years as part of the analysis of potential indicators of negative evidence. In each tax jurisdiction, certain entities recognized a cumulative loss on the basis of the most recent three years’ pretax results as of March 31, 2019. As it pertains to each entity with a cumulative loss, a valuation allowance was fully recognized against the deferred tax assets if the Group determined there was no positive evidence that overcame the negative evidence. MHFG and its principal banking subsidiaries in Japan did not record cumulative losses in the periods presented. Change in valuation allowance The following table presents a roll-forward of the valuation allowance for the fiscal years ended March 31, 2017, 2018 and 2019: 2017 2018 2019 (in millions of yen) Balance at beginning of fiscal year 339,922 438,344 163,358 Changes that directly affected Income tax expense 112,781 (9,102 ) (2,444 ) Changes that did not affect Income tax expense: Expiration of net operating loss carryforwards — (264,234 ) — Others (14,359 ) (1,650 ) (2,333 ) Total (14,359 ) (265,884 ) (2,333 ) Balance at end of fiscal year 438,344 163,358 158,581 The increase in the fiscal year ended March 31, 2017 of ¥112,781 million in the valuation allowance that directly affected Income tax expense was a result of an assessment of realizability of deferred tax assets related to the net operating loss carryforwards, primarily related to the reversal of an outside basis difference related to certain foreign subsidiaries due to their organizational restructuring. The decrease in the fiscal year ended March 31, 2017 of ¥14,359 million in others was primarily related to a decrease in the valuation allowance that is fully recognized against the MHFG Group’s net operating loss carryforwards due to tax rate reductions and foreign currency rate reductions of MHFG’s foreign subsidiaries. The decrease in the fiscal years ended March 31, 2018 and 2019 of ¥9,102 million and ¥2,444 million, respectively, in the valuation allowance that directly affected Income tax expense was primarily related to an increase of the realizability of deferred tax assets of MHFG’s subsidiaries. Net operating loss carryforwards At March 31, 2019, the MHFG Group had net operating loss carryforwards totaling ¥683 billion. These carryforwards are scheduled to expire as follows: Net operating loss (in billions of yen) Fiscal year ending March 31: 2020 — 2021 — 2022 — 2023 12 2024 3 2025 and thereafter (Note) 668 Total 683 Note: Including the net operating loss carryforwards which may be carried forward indefinitely in the United Kingdom. In addition, included in the net operating loss carryforwards in the above table are MHSC’s net operating loss carryforwards of ¥350 billion resulting mainly from the reversal of an outside basis difference related to certain foreign subsidiaries due to their organizational restructuring. The tax loss was recorded at MHSC in accordance with Japanese tax law. The net operating loss carryforwards due to this restructuring will expire during the fiscal year ending March 31, 2026. Uncertainty in income tax The following table is a roll-forward of unrecognized tax benefits for the fiscal years ended March 31, 2017, 2018 and 2019: 2017 2018 2019 (in millions of yen) Total unrecognized tax benefits at beginning of fiscal year 1,300 1,867 2,345 Gross amount of increases related to positions taken during prior years 167 224 9,550 Gross amount of increases related to positions taken during the current year 409 351 330 Amount of decreases related to settlements — — — Foreign exchange translation (9 ) (97 ) 98 Total unrecognized tax benefits at end of fiscal year 1,867 2,345 12,323 The total amount of unrecognized tax benefits including ¥675 million, ¥888 million and ¥2,164 million of interest and penalties was ¥1,867 million, ¥2,345 million and ¥12,323 million at March 31, 2017, 2018 and 2019, respectively, which would, if recognized, affect the Group’s effective tax rate. The Group classifies interest and penalties accrued relating to unrecognized tax benefits as Income tax expense. The MHFG Group is currently subject to ongoing tax audits in some jurisdictions. The oldest years open to tax audits in Japan, the United States and the United Kingdom are 2010, 2002 and 2015, respectively. It is reasonably possible that unrecognized tax benefits may decrease by approximately ¥9 billion within the next twelve months due to the resolution of various audits.

Pension and other employee bene

Pension and other employee benefit plans	12 Months Ended
	Mar. 31, 2019
Pension and other employee benefit plans	21. Pension and other employee benefit plans Severance indemnities and pension plans MHFG and certain subsidiaries sponsor and offer their employees, other than directors and corporate auditors, contributory and non-contributory lump-sum lump-sum Certain foreign offices and subsidiaries have defined contribution plans and/or defined benefit plans, of which disclosures are combined with those for domestic benefit plans, as they are not significant. MHFG and certain subsidiaries have several defined contribution plans. The costs recognized in respect of contributions to the plans for the fiscal years ended March 31, 2017, 2018 and 2019 were ¥3,141 million, ¥2,511 million and ¥3,217 million, respectively. Pension plans are not fully integrated among subsidiaries of MHFG and plan assets are managed separately by each plan. Net periodic benefit cost and funded status The following table presents the components of net periodic cost of the severance indemnities and pension plans for the fiscal years ended March 31, 2017, 2018 and 2019: 2017 2018 2019 (in millions of yen) Service cost-benefits earned during the fiscal year 44,367 43,649 43,698 Interest costs on projected benefit obligations 5,724 7,471 6,933 Expected return on plan assets (35,969 ) (34,916 ) (38,518 ) Amortization of prior service cost (benefits) (195 ) 214 152 Amortization of net actuarial loss (gain) 780 411 (7,886 ) Special termination benefits 3,857 3,960 2,929 Net periodic benefit cost 18,564 20,789 7,308 Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss) before-tax 2018 2019 (in millions of yen) Net actuarial gain (loss) 216,777 (21,300 ) Amortization of net actuarial loss (gain) 411 (7,886 ) Prior service benefits (cost) (348 ) (109 ) Amortization of prior service cost (benefits) 214 152 Total recognized in other comprehensive income (loss) before-tax 217,054 (29,143 ) As of March 31, 2019, the amounts in Accumulated other comprehensive income (loss), which will be amortized as prior service costs and actuarial gain over the next fiscal year, are estimated to be ¥163 million and ¥5,627 million, respectively. Weighted-average assumptions used to determine benefit obligations and net periodic benefit cost are as follows: 2017 2018 2019 Weighted-average assumptions used to determine benefit obligations at fiscal year end: Discount rates 0.47 % 0.43 % 0.34 % Rates of increase in future compensation levels 1.80-4.80 % 1.80-4.80 % 1.80-4.80 % Weighted-average assumptions used to determine net periodic benefit cost during the year: Discount rates 0.37 % 0.47 % 0.43 % Rates of increase in future compensation levels 1.80-4.80 % 1.80-4.80 % 1.80-4.80 % Expected rates of return on plan assets 1.73 % 1.58 % 1.60 % In estimating the discount rates, the MHFG Group uses interest rates on high-quality fixed-income government and corporate bonds. The durations of these bonds closely match those of the benefit obligations. Assumed discount rates are reevaluated at each measurement date. The expected rate of return for each asset category is based primarily on various aspects of the long-term prospects for the economy that include historical performance and the market environment. The following table sets forth the combined funded status and amounts recognized in the accompanying consolidated balance sheets at March 31, 2018 and 2019 for the plans of MHFG and its subsidiaries: 2018 2019 (in millions of yen) Change in benefit obligations: Benefit obligations at beginning of fiscal year 1,545,893 1,559,356 Service cost 43,649 43,698 Interest cost 7,471 6,933 Plan participants’ contributions 1,233 1,229 Amendments 348 109 Actuarial loss (gain) 30,633 49,085 Foreign exchange translation (32 ) (817 ) Benefits paid (53,167 ) (52,618 ) Lump-sum (16,672 ) (16,157 ) Benefit obligations at end of fiscal year 1,559,356 1,590,818 Change in plan assets: Fair value of plan assets at beginning of fiscal year 2,200,812 2,405,730 Actual return (negative return) on plan assets 280,251 66,652 Foreign exchange translation (113 ) (390 ) Partial withdrawal of assets from employee retirement benefits trusts (Note) (66,565 ) (27,534 ) Employer contributions 43,279 20,487 Plan participants’ contributions 1,233 1,229 Benefits paid (53,167 ) (52,618 ) Fair value of plan assets at end of fiscal year 2,405,730 2,413,556 Funded status 846,374 822,738 Amounts recognized in the consolidated balance sheets consist of: Prepaid pension cost 874,191 850,472 Accrued pension liability (27,817 ) (27,734 ) Net amount recognized 846,374 822,738 Amounts recognized in Accumulated other comprehensive income (loss) before-tax Prior service benefits (cost) (1,352 ) (1,309 ) Net actuarial gain (loss) 291,230 262,044 Net amount recognized 289,878 260,735 Note: During the fiscal year ended March 31, 2018 and 2019, a subsidiary of MHFG partially withdrew assets from employee retirement benefit trusts, which were established for the payment of employees’ severance pay and retirement pensions. Overall, the trusts remain in overfunded status as of March 31, 2018 and 2019. No gains or losses have been recognized as a result of this transaction. The aggregated accumulated benefit obligations of these plans were ¥1,559,356 million and ¥1,590,818 million, as of March 31, 2018 and 2019, respectively. The defined benefit plans generally employ a multi-variable and non-linear lump-sum The following table shows the projected benefit obligations and the fair value of plan assets for the plans of MHFG and its subsidiaries with projected benefit obligations in excess of plan assets, and the accumulated benefit obligations and the fair value of plan assets for the plans with accumulated benefit obligations in excess of plan assets at March 31, 2018 and 2019: 2018 2019 (in millions of yen) Plans with projected benefit obligations in excess of plan assets: Projected benefit obligations 59,319 61,579 Fair value of plan assets 31,503 33,845 Plans with accumulated benefit obligations in excess of plan assets: Accumulated benefit obligations 59,319 61,579 Fair value of plan assets 31,503 33,845 Note: The plans with projected benefit obligations in excess of plan assets include those with accumulated benefit obligations in excess of plan assets. Investment policies and asset allocation In managing plan assets, the MHFG Group determines the appropriate levels of risk that the Group can assume under the given circumstances to maximize the investment returns from a long-term perspective while ensuring that the sufficient funds will be available to plan participants and beneficiaries. Generally, the investment returns are relative to the risks involved. In considering the maximum levels of risk that the MHFG Group can assume, it primarily considers the following factors; the employers’ burden of maintaining the benefit plans based on the design of the plans and future plan contributions, the age distribution of the plan participants and beneficiaries, the financial conditions of the employers, and the employers’ ability to absorb future variability in plan premiums. The long-term asset allocation to each asset category such as Japanese equity securities, Japanese debt securities, foreign equity securities and foreign debt securities is determined based upon the optimal portfolio, which is estimated to yield the maximum return within the range of an acceptable level of risk. Additionally, the asset allocation is reviewed whenever there are large fluctuations in pension plan liabilities caused by modifications of pension plans, or there are changes in the market environment. When selecting an investment in each asset category, the MHFG Group takes into consideration credit standing of an investee, concentration of credit risk to a certain investee and liquidity of a financial instrument among other things. The investments in each asset category are further diversified across funds, strategies and sectors along with other things. There is no significant investment in a single investee except Japanese government bonds. Certain subsidiaries of MHFG established employee retirement benefit trusts and transferred their assets to the trusts as plan assets. These assets are separated from the employer’s proprietary assets for the payment to the plan beneficiaries. The assets held in these trusts are primarily Japanese equity securities and have been entrusted directly to qualified trustees including trust banks. MHFG and certain subsidiaries’ target allocation for the plan assets, excluding those of the employee retirement benefit trusts, at March 31, 2019 is as follows: Asset category Asset ratio Japanese equity securities 5.00 % Japanese debt securities 34.00 % Foreign equity securities 25.00 % Foreign debt securities 23.00 % General account of life insurance companies 11.00 % Other 2.00 % Total 100.00 % Note: General account of life insurance companies is a contract with life insurance companies which guarantees payments of principal and predetermined interest payments. Fair value of plan assets The following table presents the fair value of plan assets of MHFG and its subsidiaries at March 31, 2018 and 2019, by asset class. For the detailed information on fair value measurements, including descriptions of Level 1, 2 and 3 of the fair value hierarchy and the valuation methodologies, see Note 28 “Fair value”. 2018 2019 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (in billions of yen) Japanese equity securities: Common stocks (1) 1,330 — — 1,330 1,317 — — 1,317 Pooled funds (2) 10 9 — 19 11 4 — 15 Japanese debt securities: Government bonds 184 — — 184 190 — — 190 Pooled funds (2) — 4 — 4 — 10 — 10 Other — 25 — 25 — 24 — 24 Foreign equity securities: Common stocks 108 — — 108 120 — — 120 Pooled funds (2) — 5 — 5 — 5 — 5 Foreign debt securities: Government bonds 175 6 — 181 178 6 — 184 Pooled funds (2) — 9 — 9 — 10 — 10 Other — 16 — 16 — 18 — 18 General account of life insurance companies (3) — 110 — 110 — 111 — 111 Other 92 (4) — — 92 79 (4) 4 — 83 Plan assets measured at net asset (5) 323 327 Total assets at fair value 1,899 184 — 2,406 1,895 192 — 2,414 Notes: (1) This class represents equity securities held in the employee retirement benefit trusts of ¥1,330 billion and ¥1,317 billion carried at fair value at March 31, 2018 and 2019, respectively, which are well-diversified across industries. (2) These classes primarily include pension investment fund trusts. Investments in these classes are generally measured at fair value and can be redeemed within a short-term period upon request. (3) Investments in this class are measured at conversion value, which is equivalent to fair value. (4) Amounts primarily include cash and short-term assets carried at fair value. (5) In accordance with ASC 820, certain plan assets that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. There were no returns on and purchases and sales of Level 3 assets during the fiscal years ended March 31, 2018 and 2019. Contributions The total contribution of approximately ¥52 billion is expected to be paid to the pension plans during the fiscal year ending March 31, 2020, based on the current funded status and expected asset return assumptions. Estimated future benefit payments The following table presents forecasted benefit payments including the effect of expected future service for the fiscal years indicated: (in millions of yen) Fiscal year ending March 31: 2020 68,890 2021 70,015 2022 70,637 2023 71,370 2024 72,606 2025-2029 351,719

Stock-based compensation

Stock-based compensation	12 Months Ended
	Mar. 31, 2019
Stock-based compensation	22. Stock-based compensation Stock options MHFG, MHBK, MHTB and MHSC have stock options, in the form of stock acquisition rights, for directors (excluding the outside directors) and executive officers of the respective companies (hereinafter referred to collectively as the “Directors”). In this plan (“MHFG Stock Plan”), 1,000 shares of MHFG common stock shall be issued or transferred upon exercise of each of the stock acquisition rights. The exercise price is 1 yen per share. The contractual term of the stock acquisition rights is 20 years. A holder may exercise the stock acquisition rights only after the date on which such holder loses the status as a Director of MHFG, MHBK, MHTB or MHSC. The following is a roll-forward of MHFG Stock Plan for the fiscal year ended March 31, 2019: Number of Weighted-average Weighted-average Aggregate (in yen) (in years) (in millions of yen) Outstanding at beginning of fiscal year 7,216,000 1 Exercised during fiscal year 2,971,000 1 Outstanding at end of fiscal year 4,245,000 1 14.81 723 Exercisable at end of fiscal year — — — — There were no non-vested In May 2015, MHFG discontinued the stock option program. Thereafter, MHFG has not issued any new stock options. Stock compensation programs MHFG, MHBK, MHTB and MHSC introduced a position-based stock compensation program for Directors (“Stock Compensation I”) in July 2018 and a performance-based stock compensation program for Directors (“Stock Compensation II”) in May 2015. The stock compensation is paid in the form of shares of common stock of MHFG, acquired from the stock market through a trust, with the aim of aligning the Directors’ interests with those of the shareholders and increasing the incentive to enhance corporate value. Stock Compensation I, in principle, is paid at the time of retirement of the individual Directors in the form of common stock of MHFG and cash, calculated based on their position. Stock Compensation II is calculated and then paid to the Directors based on MHFG Group’s immediate, prior period-performance, the recent performance of organizations that the Directors are in charge of, and the performance of each Director. The payment in the form of common stock of MHFG and cash is deferred over a three-year, graded-vesting period. The amount of Stock Compensation I and II is subject to reduction or forfeiture. The following table presents activities related to the stock compensation programs for the fiscal years ended March 31, 2018 and 2019: Stock Compensation I Stock Compensation II 2018 Number of Weighted-average grant-date fair Number of Weighted-average grant-date fair (per share in yen) (per share in yen) Nonvested at the beginning of the year — — 9,000,000 158.68 Granted during fiscal year — — 8,130,000 196.94 Vested during fiscal year — — 3,810,594 158.68 Forfeited during fiscal year — — — — Nonvested at the end of the year — — 13,319,406 182.04 Stock Compensation I Stock Compensation II 2019 Number of Weighted-average grant-date fair Number of Weighted-average grant-date fair (per share in yen) (per share in yen) Nonvested at the beginning of the year — — 13,319,406 182.04 Granted during fiscal year 3,770,065 189.24 6,906,635 189.24 Vested during fiscal year 3,770,065 189.24 5,068,949 187.48 Forfeited during fiscal year — — — — Nonvested at the end of the year — — 15,157,092 183.50 Note: Stock Compensation I was introduced in the fiscal year ended March 31, 2019. The following table presents the total fair value of the stock compensation that vested and the total amount of the common stock acquired from the stock market by the trustee for the fiscal years ended March 31, 2018 and 2019: 2018 2019 Stock Stock Stock Stock (in millions of yen) Fair value of vested shares — 782 713 930 Common stock shares acquired — 1,601 713 1,307 For both programs, the stock-based compensation cost is determined based on the fair value of MHFG’s common stock as of grant date. For Stock Compensation I and II, the liability related to the cash-based compensation cost is remeasured at each reporting date based on the fair value of MHFG’s common stock. For Stock Compensation II, the stock-based compensation costs are recognized evenly over the graded-vesting period, which is three years. For Stock Compensation I, as the program is effectively vested on the grant date, the stock-based compensation cost is recognized on the grant date. The following table presents the compensation cost recognized in the stock compensation programs for the fiscal years ended March 31, 2017, 2018 and 2019: 2017 2018 2019 (in millions of yen) Stock Compensation I: — — 713 Stock Compensation II: 354 868 1,287 With regard to Stock Compensation II, the total compensation cost related to non-vested

Derivative financial instrument

Derivative financial instruments	12 Months Ended
	Mar. 31, 2019
Derivative financial instruments	23. Derivative financial instruments The MHFG Group enters into derivative financial instruments in response to the diverse needs of customers, to control the risk related to the assets and liabilities of the MHFG Group, as part of its asset and liability management, and for proprietary trading purposes. The MHFG 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 MHFG 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, 2018 and 2019. 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) 2018 Notional amount (1) Designated Not designated Designated Not designated (in billions of yen) Interest rate contracts 1,004,169 — 7,176 — 7,143 Foreign exchange contracts 155,832 2 2,695 — 2,382 Equity-related contracts 6,189 — 197 9 142 Credit-related contracts 2,708 — 18 — 21 Other contracts 335 — 23 — 19 Total 1,169,233 2 10,109 9 9,707 Fair value Derivative receivables (2) Derivative payables (2) 2019 Notional amount (1) Designated Not designated Designated Not designated (in billions of yen) Interest rate contracts 1,052,267 — 5,786 — 5,610 Foreign exchange contracts 166,383 — 1,959 — 1,758 Equity-related contracts 5,181 — 125 — 142 Credit-related contracts 2,939 — 18 — 17 Other contracts 438 — 16 — 14 Total 1,227,208 — 7,904 — 7,541 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 ¥981 billion and ¥599 billion at March 31, 2018, and ¥856 billion and ¥589 billion at March 31, 2019, 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. Any ineffectiveness must be reported immediately in earnings. The MHFG Group’s hedging activities include fair value and net investment hedges. Fair value hedges The MHFG Group primarily uses forward contracts to modify exposure to changes in the fair value of Equity securities. The Group adopted ASU No.2016-01 Before the adoption of the ASU, for qualifying fair value hedges, all changes in the fair value of the derivative and the corresponding hedged item relating to the risk being hedged were recognized in earnings in Investment gains (losses)—net. The change in fair value of the portion of the hedging instruments excluded from the assessment of hedge effectiveness was recorded in Trading account gains (losses)—net. No ineffectiveness existed because the MHFG Group chose to exclude changes in the differences between the spot and the forward prices from the effectiveness test. If the hedge relationship was terminated, the fair value adjustment to the hedged item continued to be reported as part of the basis of the item. The fair value adjustment was recognized in earnings upon the sale of the hedged item. The following table summarizes gains and losses information related to fair value hedges for the fiscal years ended March 31, 2017, 2018: Gains (losses) recorded in income 2017 Derivatives Hedged Hedge Net gain (loss) excluded (in millions of yen) Equity-related contracts (14,747 ) 11,393 — (3,354 ) Total (14,747 ) 11,393 — (3,354 ) Gains (losses) recorded in income 2018 Derivatives Hedged Hedge Net gain (loss) excluded (in millions of yen) Equity-related contracts (23,832 ) 19,631 — (4,201 ) Total (23,832 ) 19,631 — (4,201 ) 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 The following table summarizes gains and losses information related to net investment hedges for the fiscal years ended March 31, 2017, 2018 and 2019: Gains (losses) recorded in income and other comprehensive income (“OCI”) 2017 2018 2019 Effective portion Ineffective portion Effective portion Ineffective portion Effective portion Ineffective portion (in millions of yen) Financial instruments hedging foreign exchange risk 16,767 47 (30 ) 90 7,405 107 Total 16,767 47 (30 ) 90 7,405 107 Note: Related to the effective portion of net investment hedges, gains of ¥41 million and ¥186 million were reclassified from Accumulated other comprehensive income to earnings for the fiscal years ended March 31, 2017 and 2019, respectively. No amount related to the effective portion of net investment hedges was reclassified from Accumulated other comprehensive income to earnings for the fiscal year ended March 31, 2018. 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, and (3) 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 gain (loss) resulting from changes in the fair value of certain credit derivatives where the Group purchases protection to mitigate its credit risk exposure, related to its corporate loan portfolio, is recorded in Other noninterest income (expenses). The following table summarizes gains and losses on derivatives not designated or qualifying as hedges during the fiscal years ended March 31, 2017, 2018 and 2019: Gains (losses) recorded in income 2017 2018 2019 (in millions of yen) Interest rate contracts (209,361 ) (63,260 ) 127,242 Foreign exchange contracts 37,129 61,046 6,748 Equity-related contracts (1) 5,131 (94,607 ) 37,875 Credit-related contracts (2) (6,694 ) (2,830 ) (467 ) Other contracts 742 6,330 (1,455 ) Total (173,053 ) (93,321 ) 169,943 Notes: (1) The net gain (loss) excluded from the assessment of the effectiveness of fair value hedges is not included in the above table. (2) Amounts include the net loss of ¥7,594 million, ¥754 million and ¥736 million on the credit derivatives economically managing the credit risk of loans during the fiscal years ended March 31, 2017, 2018 and 2019, 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, 2018 and 2019: 2018 2019 Notional amount Fair value Notional amount Fair value (in billions of yen) Credit protection written: Investment grade 1,105 15 1,266 12 Non-investment 197 4 199 3 Total 1,302 19 1,465 15 Credit protection purchased 1,541 (22 ) 1,628 (14 ) 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, 2018 and 2019: Maximum payout/Notional amount 2018 2019 (in billions of yen) One year or less 329 326 After one year through five years 831 1,057 After five years 142 82 Total 1,302 1,465 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, 2018 and 2019: 2018 2019 (in billions of yen) Aggregate fair value of derivative instruments with credit-risk-related contingent features in net liability positions 572 511 Collateral provided to counterparties in the normal course of business 593 489 Amount required to be posted as collateral or settled immediately if credit-risk-related contingent features were triggered (Note) — 22 Note: There was no amount that the Group would be required to post as collateral or settle immediately on March 31, 2018.

Commitments and contingencies

Commitments and contingencies	12 Months Ended
	Mar. 31, 2019
Commitments and contingencies	24. Commitments and contingencies Obligations under guarantees The MHFG Group provides guarantees or indemnifications to counterparties to enhance their credit standing and enable them to complete a variety of business transactions. A guarantee represents an obligation to make payments to third parties if the counterparty fails to fulfill its obligation under a borrowing arrangement or other contractual obligation. The types of guarantees under ASC 460, “Guarantees” (“ASC 460”) provided by the MHFG Group are described below. Performance guarantees Performance guarantees are issued to guarantee customers’ performance under contractual arrangements such as a tender bid on a construction project or the completion of a construction project. Guarantees on loans Guarantees on loans include obligations to guarantee the customers’ borrowing contracts. The MHFG Group is required to make payments to the guaranteed parties in the event that customers fail to fulfill obligations under the contracts. Guarantees on securities Guarantees on securities include obligations to guarantee securities, such as bonds issued by customers. Other guarantees Other guarantees include obligations to guarantee customers’ payments, such as tax payments. Guarantees for the repayment of trust principal The MHFG Group provides certain trust products with guarantees for the repayment of trust principal, e.g., loan trusts and certain jointly operated designated money trusts. Pursuant to Japanese trust-related laws, trustees are prohibited from compensating beneficiaries for any loss in the beneficial interests in each trust. However, under a special condition of the Japanese trust-related laws, trust banks as trustees are allowed to enter into an agreement to provide compensation for any loss in the principal of the trust. The MHFG Group manages and administers the trust assets to minimize exposures against losses from the guarantees for the repayment of trust principal, including writing-off Part of the trust account profits is set aside as a reserve in trust accounts to absorb losses in the trust asset portfolios in accordance with relevant Japanese laws concerning the trust business and/or trust agreements. Statutory reserves for loan trusts and reserves for jointly operated designated money trusts are calculated based on the trust principal or the balance of loans and other assets in the trust accounts. Since the probability of principal indemnification is considered to be remote, the MHFG Group had no related reserve for credit losses recorded in its consolidated financial statements. Liabilities of trust accounts The MHFG Group, as trustee, may enter into an agreement with a third party who is not the party to the relevant trust agreement to the extent necessary to handle the trust affairs for the purpose of fulfilling the objectives of the trust and, as such, the trustee shall be allowed to assume certain liabilities. Pursuant to Japanese trust-related laws, the trustee is ultimately liable to pay those liabilities out of its proprietary assets in the event that the trust assets are insufficient to cover those liabilities. The amount of trust liabilities rarely exceeds the amount of trust assets and, therefore, those liabilities are generally covered by the corresponding trust assets. To avoid the demand for payment out of the proprietary assets, the trustee can enter into a special covenant of limited liability under which the trust creditors agree to limit the trustee’s liability to the value of the trust assets and to waive the right for compulsory execution against the trustee’s proprietary assets. The MHFG Group regularly monitors the condition of trust accounts to minimize exposures against making payment. The amounts of such liabilities in the trust accounts, excluding those with the special covenant of limited liability, are presented in the tables below. Liabilities of trust accounts principally include obligations to return collateral under security lending transactions and other transactions. Derivative financial instruments Certain written options and credit default swaps are deemed guarantees pursuant to the definition of guarantees in ASC 460 if these contracts require the MHFG Group to make payments to counterparties based on changes in an underlying instrument or index that is related to an asset, a liability, or an equity security of the counterparties. The MHFG Group’s payments could involve a gross settlement or a net settlement. Because it is difficult in practice to determine whether the counterparty has the asset, the liability or the equity security relating to the underlying, the MHFG Group has decided to include all credit default swaps and written options, excluding written options outside the scope of ASC 460, in the guarantee disclosures. The MHFG Group records all guarantees and similar obligations subject to ASC 460 at fair value in the consolidated balance sheets at the inception of the guarantee. The total carrying amount of guarantees and similar obligations at March 31, 2018 and 2019 was ¥82 billion and ¥109 billion, respectively, and was included in Other liabilities and Trading account liabilities. The total includes the carrying amounts of derivatives that are deemed to be guarantees, which amounted to ¥62 billion and ¥90 billion at March 31, 2018 and 2019, respectively. The table below summarizes the remaining term and maximum potential amount of future payments by type of guarantee at March 31, 2018 and 2019. The maximum potential amount of future payments disclosed below represents the contractual amounts that could be required to be repaid in the event of the guarantees being executed, without consideration of possible recoveries under recourse provisions or from collateral held. With respect to written options included in derivative financial instruments in the table below, in theory, the MHFG Group is exposed to unlimited losses; therefore, the table shows the notional amounts of the contracts as a substitute for the maximum exposure. The MHFG Group, when necessary, requires collateral such as cash, investment securities and real estate or third-party guarantees depending on the amount of credit risk involved, and employs means such as sub-participation 2018 Maximum Amount by expiration period One year or less After one year After five years (in billions of yen) Performance guarantees 2,165 1,084 908 173 Guarantees on loans 241 123 28 90 Guarantees on securities 164 32 132 — Other guarantees 2,210 1,555 614 41 Guarantees for the repayment of trust principal 709 639 49 21 Liabilities of trust accounts 13,861 13,546 149 166 Derivative financial instruments 11,654 4,911 4,996 1,747 2019 Maximum Amount by expiration period One year or less After one year After five years (in billions of yen) Performance guarantees 2,307 1,265 878 164 Guarantees on loans 289 164 46 79 Guarantees on securities 145 91 54 — Other guarantees 2,324 1,447 834 43 Guarantees for the repayment of trust principal 65 — 47 18 Liabilities of trust accounts 362 61 148 153 Derivative financial instruments 14,170 5,807 6,434 1,929 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, 2018 and 2019: 2018 2019 (in billions of yen) Investment grade 3,930 4,124 Non-investment 850 941 Total 4,780 5,065 Note: Investment grade in the internal rating scale generally corresponds to BBB- or above in the external rating scale. Other off-balance-sheet In addition to guarantees, the MHFG Group issues other off-balance-sheet Commitments to extend credit Commitments to extend credit are legally binding agreements to lend to customers on demand. They usually have set maturity dates. These agreements differ from guarantees in that they are generally revocable or contain provisions that enable the MHFG Group to avoid payment or reduce the amount of credit extended under certain conditions, such as the deterioration of the borrower’s financial condition or other reasonable conditions. The MHFG Group monitors the financial condition of the potential borrowers throughout the commitment period to determine whether additional collateral or changes in the terms of the commitment are necessary. Since many of these commitments to extend credit expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. Commitments to invest in securities Commitments to invest in securities include legally binding contracts to make additional contributions to investment funds, such as private equity funds in accordance with the terms of investment agreements. Commercial letters of credit Commercial letters of credit are issued in connection with customers’ trade transactions. Normally, the customers cannot receive the goods until they make payment to a bank, and therefore these commercial letters of credit are collateralized by the underlying goods. Upon issuance of commercial letters of credit, the MHFG Group monitors the credit risk associated with these transactions to determine if additional collateral is required. The table below summarizes the contractual amounts with regard to these undrawn commitments at March 31, 2018 and 2019: 2018 2019 (in billions of yen) Commitments to extend credit (Note) 78,448 76,857 Commercial letters of credit 690 778 Total 79,138 77,635 Note: Commitments to extend credit include commitments to invest in securities. Allowance for losses on off-balance-sheet The amounts of allowance for losses on off-balance-sheet Leases The MHFG Group leases certain office space and equipment under noncancelable agreements. The lease periods for these leases range from less than 1 year to around 30 years. These leases include cancellation clauses with penalties of a maximum of approximately 5 years-worth of rentals and/or periodic adjustment clauses of rentals. The table below shows future minimum lease payments for capitalized leases and future minimum rental payments for operating leases at March 31, 2019: Capitalized leases Operating leases (in millions of yen) Fiscal year ending March 31: 2020 9,942 51,329 2021 7,347 41,227 2022 4,454 34,707 2023 2,661 24,633 2024 915 23,425 2025 and thereafter 222 297,183 Total minimum lease/rental payments 25,541 472,504 Amount representing interest 25,020 Present value of minimum lease payments 521 Total rental expense for the fiscal years ended March 31, 2017, 2018 and 2019 was ¥113,991 million, ¥117,270 million and ¥115,239 million, respectively. MHFG leases its head office from a third party and accounts for the lease arrangement as an operating lease. During prior years, the MHFG Group’s major banking subsidiaries sold their head offices (including land, buildings, facilities and equipment) to third parties. Concurrent with the sales, these subsidiaries leased the properties back for periods of 5 and 10 years for total rental payments for these periods of ¥214,690 million. The terms of certain lease agreements were changed during the fiscal years ended March 31, 2009, 2011, 2012 and 2014, and the total rental payments for these periods increased to ¥282,832 million, as a consequence. The MHFG Group accounted for the transactions as operating leases. The future minimum rental payments under the terms of the related lease agreements were ¥41,430 million, ¥32,977 million and ¥24,525 million at March 31, 2017, 2018 and 2019, respectively. Legal proceedings The MHFG Group is involved in normal collection proceedings initiated by the Group and other legal proceedings in the ordinary course of business. The Group’s Indonesian subsidiary acts as the collateral agent for the trustee of bond issuances made by subsidiaries of Asia Pulp & Paper Company Ltd. (“APP”). In that role, the subsidiary is involved in a dispute between the bondholders and such APP subsidiaries in their capacities as the issuers, guarantors and/or pledgors of security for the bonds relating to foreclosure proceedings in respect of the collateral. The subsidiary has been named as a defendant in a lawsuit brought by the obligors under the bonds in Indonesia. The Group’s consolidated financial statements do not include a reserve in relation to this dispute and the Group does not believe that the resolution of this matter will have a significant impact on the consolidated financial condition or results of operations of the Group, although there can be no assurance as to the foregoing.

Variable interest entities and

Variable interest entities and securitizations	12 Months Ended
	Mar. 31, 2019
Variable interest entities and securitizations	25. 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, as of March 31, 2018 and 2019: Consolidated VIEs Significant 2018 Consolidated assets Total assets Maximum (in billions of yen) Asset-backed commercial paper/loan programs 2,185 — — Asset-backed securitizations 627 78 5 Investments in securitization products 374 — — Investment funds 2,661 1,891 533 Trust arrangements and other 21 — — Total 5,868 1,969 538 Consolidated VIEs Significant 2019 Consolidated assets Total assets Maximum (in billions of yen) Asset-backed commercial paper/loan programs 2,249 — — Asset-backed securitizations 571 70 8 Investments in securitization products 372 — — Investment funds 2,836 1,280 410 Trust arrangements and other 20 — — Total 6,048 1,350 418 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, 2018 and 2019: Assets on balance sheets related to unconsolidated VIEs: 2018 2019 (in billions of yen) Trading account assets 89 104 Investments 210 168 Loans 163 71 Total 462 343 Liabilities on balance sheets and maximum exposure to loss related to unconsolidated VIEs: 2018 2019 (in billions of yen) Payables under securities lending transactions 38 47 Trading account liabilities 1 1 Total 39 48 Maximum exposure to loss (Note) 538 418 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 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 certain VIEs, where the MHFG Group provides liquidity and credit support facilities, writes credit protection or invests in debt or equity instruments in its role as an arranger, servicer, administrator or asset manager, etc., the Group has the power to determine which assets will be held by the VIEs or to manage and monitor these assets. In addition, through the variable interests above, the Group has the obligation to absorb losses and the right to receive benefits that could potentially be significant to the VIEs. Therefore, the Group consolidates such VIEs. The MHFG Group established certain VIEs to securitize its own mortgage loans. The Group provides servicing for and holds retained subordinated beneficial interests in the securitized mortgage loans. In addition, the Group retains credit exposure in the form of guarantees on these loans. In its role as a servicer, the Group has the power to direct the entity’s activities that most significantly impact the entity’s economic performance by managing defaulted mortgage loans. In addition, through its retained interests and its aforementioned involvement as a guarantor, the Group has the obligation to absorb losses and the right to receive benefits that could potentially be significant to the entity. Therefore, the Group consolidates such VIEs. 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. However, 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 consolidates certain investment funds where it is deemed to be the primary beneficiary. Prior to April 1, 2016, the Group determined that certain investment funds managed by the Group that had attributes of an investment company (or similar entity) qualified for the deferral from certain requirements of ASC 810 that originated from Statement of Financial Accounting Standards (“SFAS”) No.167 “Amendments to FASB Interpretation No.46(R)” (“SFAS No.167”). For these funds, the Group determined whether it was the primary beneficiary by evaluating whether it absorbed the majority of expected losses, received the majority of expected residual returns, or both. On April 1, 2016, the Group adopted ASU No.2015-02 Upon the adoption of ASU No.2015-02, 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. 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 24 “Commitments and contingencies” for the balances of guaranteed trust principal that are not consolidated at March 31, 2018 and 2019. With respect to non-guaranteed non-guaranteed 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. 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. 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 are met. These criteria are (1) the transferred financial assets are legally isolated from the Group’s creditors, (2) the transferee or beneficial interest holder has the right to pledge or exchange the transferred financial assets, and (3) the Group does not maintain effective control over the transferred financial assets. If all the criteria are not met, the transfer is accounted for as a secured borrowing. For the fiscal years ended March 31, 2017, 2018 and 2019, 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, 2018 and 2019. 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 ¥208 billion and ¥89 billion as of March 31, 2018, and ¥207 billion and ¥143 billion as of March 31, 2019, 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 consolidated balance sheets.

Noninterest income

Noninterest income	12 Months Ended
	Mar. 31, 2019
Noninterest income	26. Noninterest income Details of Noninterest income for the fiscal years ended March 31, 2017, 2018 and 2019 are as follows: 2017 2018 2019 (in millions of yen) Fee and commission income: Securities-related business (1) 165,857 180,122 145,270 Deposits and lending business (2) 164,572 156,426 152,283 Remittance business (1) 108,368 110,054 110,382 Asset management business (1) 79,426 100,765 97,852 Trust related business (1) 108,931 121,808 124,843 Agency business (1) 36,003 37,397 36,466 Guarantee related business (3) 26,292 28,258 28,582 Fees for other customer services (1) 136,514 130,881 157,612 Total Fee and commission income 825,963 865,711 853,290 Foreign exchange gains (losses)—net (3) 69,453 91,793 93,577 Trading account gains (losses)—net (2) (42,481 ) 236,982 328,841 Investment gains (losses)—net: Debt securities (3) 59,517 7,757 (3,842 ) Equity securities (3) 273,753 289,400 (155,947 ) Equity in earnings (losses) of equity method investees—net (3) 26,785 24,342 29,172 Gains on disposal of premises and equipment (3) 5,638 8,225 5,145 Other noninterest income (2) 149,404 80,453 72,135 Total 1,368,032 1,604,663 1,222,371 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. Certain Fee and commission income, Trading account gains (losses)—net and Other noninterest income outlined in the table above are considered to be revenues from contracts that are within the scope of ASC 606. The MHFG Group disaggregates Fee and commission income, which is the main part of revenues within the scope of ASC 606, by type of business or service in the table above. Fee and commission income Securities-related business fees mainly consist of brokerage fees and commissions, and asset-based revenues. Brokerage fees and commissions mainly include fees earned from the execution of customer transactions and sales commissions of investment trusts. Brokerage fees and commissions are recognized at the point in time on transaction date. Asset-based revenues mainly include fees received from investment trust management companies in return for administration services, such as record keeping services, of investment trusts. The amounts of asset-based revenues are calculated based on customer’s net asset value and recognized over time in the period when the related service is provided. Deposits and lending business fees consist of deposit-related fees and lending-related fees. Most of the deposit-related fees are within the scope of ASC 606, while most of the lending-related fees such as commitment fees and arrangement fees are not. Deposit-related fees within the scope of ASC 606 include service charges on consumer and commercial deposit accounts such as account transfer charges. Deposit-related fees are recognized at the point in time when the transactions occur or the related service is provided. Remittance business fees include service charges for domestic and international funds transfers and collections. These fees are recognized at the point in time when the related service is provided. Asset management business fees consist of investment trust management fees and investment advisory fees for investment trusts. These fees are received from investment trusts in return for asset management services and/or investment advisory services on behalf of customers. The amounts of these fees are calculated based on a percentage of customer’s net asset value. These fees are recognized over time in the period when the management and/or advisory service is provided and the amount is fixed. Trust related business fees consist of trust fees earned primarily through fiduciary asset management and administrative service and other trust-related fees, which amounted to ¥51 billion and ¥74 billion for the fiscal year ended March 31, 2019, respectively. Fees for fiduciary asset management and administration services for corporate pension plans and investment funds are recognized over time in the period when the related service is provided. Other trust-related fees mainly include brokerage commissions of real estate property, sales commissions of beneficial interest in real estate trust and charges for stock transfer agent services. These fees are mainly earned on a transaction basis and recognized at the point in time when the related service is provided. Agency business fees mainly include administration service fees related to the MHFG Group’s agency business such as Japan’s principal public lottery program and revenues from standing proxy services. These fees are recognized at the point in time when the related service is provided. Fees for other customer services include various revenues such as sales commissions of life insurance, service charges for electronic banking, financial advisory fees, and service charges for software development. Sales commissions from life insurance sales are received from insurance companies in return for selling insurance products and recognized when the insurance product is sold to customers. Service charges for electronic banking are mainly monthly basic usage fees and recognized over the related transaction period. Financial advisory fees are recognized over time in the period when the related advisory service based on the contract is rendered. Service charges for software development are recognized over time according to the progress of the development. Trading account gains (losses)—net and Other noninterest income In addition to Fee and commission income, Trading account gains (losses)—net and Other noninterest income include certain revenues within the scope of ASC 606. Underwriting fees from trading securities, which amounted to ¥68 billion for the fiscal year ended March 31, 2019, are within the scope of ASC 606 and accounted for in Trading account gains (losses)—net. Underwriting fees are recognized at the point in time when trade terms are fixed. For the fiscal year ended March 31, 2019, approximately ¥26 billion of Other noninterest income was within the scope of ASC 606. Credit card interchange fees are within the scope of ASC 606 and accounted for in Other noninterest income. Credit card interchange fees are earned on credit card transactions conducted through payment networks and recognized upon settlement of the credit card payment transactions. Contract balances relating to revenues from contracts with customers subject to ASC 606 Contract assets and receivables from contracts with customers subject to ASC 606 are recognized in Accrued income or accounts receivable of Other assets. As of March 31, 2019, the balance of contract assets was not material. Contract liabilities are recognized in unearned income of Other liabilities. As of March 31, 2019, 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, 2019, the amount of expected revenues from current obligations to provide services in the future is not material. It excludes revenues from contracts less than one year or contracts that have provisions that allow the Group to recognize revenue at the amount it has the right to invoice.

Trading account gains and losse

Trading account gains and losses	12 Months Ended
	Mar. 31, 2019
Trading account gains and losses	27. Trading account gains and losses The MHFG Group performs trading activities through market making, sales, and arbitrage. Accordingly, Trading account gains (losses)—net include gains and losses from transactions undertaken for trading purposes, including both market making for customers and proprietary trading, or transactions through which the Group seeks to capture gains arising from short-term changes in market value. Trading account gains (losses)—net also include gains and losses related to changes in the fair value of derivatives and other financial instruments not eligible for hedge accounting under U.S. GAAP that are utilized to offset mainly interest rate risk related to the Group’s various assets and liabilities, as well as gains and losses related to changes in the fair value of foreign currency-denominated debt securities reported as Trading securities. Net trading gains (losses) for the fiscal years ended March 31, 2017, 2018 and 2019 are comprised of the following: 2017 2018 2019 (in millions of yen) Trading account gains (losses)—net: Trading securities 126,332 333,749 158,162 Derivative contracts: Interest rate contracts (209,361 ) (63,260 ) 127,242 Foreign exchange contracts (1) 37,129 61,046 6,748 Equity-related contracts (2) 1,777 (98,807 ) 37,875 Credit-related contracts ( 3 ) 900 (2,076 ) 269 Other contracts 742 6,330 (1,455 ) Total (42,481 ) 236,982 328,841 Foreign exchange gains (losses)—net ( 4 ) 69,453 91,793 93,577 Net trading gains (losses) 26,972 328,775 422,418 Notes: (1) Amounts include gains and losses on currency swaps. (2) The net gain (loss) excluded from the assessment of the effectiveness of fair value hedges is included in the above table. (3) Amounts do not include the net loss of ¥7,594 million, ¥754 million and ¥736 million on the credit derivatives economically managing the credit risk of loans during the fiscal years ended March 31, 2017, 2018 and 2019, respectively. The net loss is recorded in Other noninterest expenses. (4) Amounts include realized and unrealized gains and losses on both derivative instruments and nonderivative instruments. Amounts on derivative instruments include gains and losses on forward foreign exchange contracts and currency options. Amounts on nonderivative instruments include translation gains and losses related to foreign currency-denominated debt securities reported as Trading securities.

Fair value

Fair value	12 Months Ended
	Mar. 31, 2019
Fair value	28. Fair value Fair value measurements ASC 820 defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. ASC 820 also establishes a fair value hierarchy which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. In addition, ASC 820 precludes (1) the deferral of gains and losses at inception of certain derivative contracts whose fair value was not evidenced by market-observable data, and (2) the use of block discounts when measuring the fair value of instruments traded in an active market, which were previously applied to large holdings of publicly traded financial instruments. Fair value hierarchy ASC 820 specifies a hierarchy of valuation techniques based on whether the inputs to those valuation techniques are observable or unobservable. The standard describes 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 fiscal year ended March 31, 2019, 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. In the event that certain key inputs are unobservable or cannot be corroborated by observable market data, these financial instruments are classified in Level 3. Hedge funds the Group invests in are primarily multi strategy funds that employ a fundamental bottom-up start-up ten-year Derivative financial instruments Exchange-traded derivatives are valued using quoted market prices and consequently are classified in Level 1 of the fair value hierarchy. However, the majority of derivatives entered into by the Group are executed over-the-counter over-the-counter 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 securities measured at the NAV per share. These securities are determined primarily using the same procedures described under trading securities above. 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, 2018 and 2019, including those for which the MHFG Group has elected the fair value option, are summarized below: 2018 Level 1 Level 2 Level 3 Assets/ (in billions of yen) Assets: Trading securities (1) Japanese government bonds 1,375 43 — 1,418 Japanese local government bonds — 107 — 107 U.S. Treasury bonds and federal agency securities 2,442 209 — 2,651 Other foreign government bonds 1,682 480 — 2,162 Agency mortgage-backed securities — 1,799 — 1,799 Residential mortgage-backed securities — — 12 12 Certificates of deposit and commercial paper — 643 — 643 Corporate bonds and other 25 1,992 1,013 3,030 Equity securities 1,642 — 23 1,665 Trading securities measured at net asset value (2) 705 Derivative financial instruments: Interest rate contracts 39 7,089 48 7,176 Foreign exchange contracts 17 2,667 13 2,697 Equity-related contracts 82 110 5 197 Credit-related contracts — 16 2 18 Other contracts 6 8 9 23 Available-for-sale Japanese government bonds 12,435 897 — 13,332 Japanese local government bonds — 239 — 239 U.S. Treasury bonds and federal agency securities 686 — — 686 Other foreign government bonds 355 703 — 1,058 Agency mortgage-backed securities — 889 — 889 Residential mortgage-backed securities — 65 54 119 Commercial mortgage-backed securities — — 441 441 Japanese corporate bonds and other debt securities — 1,827 163 1,990 Foreign corporate bonds and other debt securities — 799 80 879 Equity securities (marketable) (3) 3,912 121 — 4,033 Other investments — — 38 38 Total assets measured at fair value on a recurring basis 24,698 20,703 1,901 48,007 Liabilities: Trading securities sold, not yet purchased 2,777 618 4 3,399 Derivative financial instruments: Interest rate contracts 42 7,074 27 7,143 Foreign exchange contracts 11 2,370 1 2,382 Equity-related contracts 81 69 1 151 Credit-related contracts — 20 1 21 Other contracts 4 6 9 19 Long-term debt (4) — 1,395 561 1,956 Total liabilities measured at fair value on a recurring basis 2,915 11,552 604 15,071 2019 Level 1 Level 2 Level 3 Assets/ (in billions of yen) Assets: Trading securities (1) Japanese government bonds 1,829 33 — 1,862 Japanese local government bonds — 134 — 134 U.S. Treasury bonds and federal agency securities 1,069 138 — 1,207 Other foreign government bonds 2,417 553 — 2,970 Agency mortgage-backed securities — 1,041 — 1,041 Residential mortgage-backed securities — — 11 11 Certificates of deposit and commercial paper — 1,047 — 1,047 Corporate bonds and other 36 1,806 1,044 2,886 Equity securities 1,297 — 28 1,325 Trading securities measured at net asset value (2) 631 Derivative financial instruments: Interest rate contracts 36 5,729 21 5,786 Foreign exchange contracts 9 1,927 23 1,959 Equity-related contracts 58 63 4 125 Credit-related contracts — 16 2 18 Other contracts 2 4 10 16 Available-for-sale Japanese government bonds 10,902 995 — 11,897 Japanese local government bonds — 210 — 210 U.S. Treasury bonds and federal agency securities 1,009 — — 1,009 Other foreign government bonds 456 886 — 1,342 Agency mortgage-backed securities — 544 — 544 Residential mortgage-backed securities — 61 40 101 Commercial mortgage-backed securities — — 500 500 Japanese corporate bonds and other debt securities — 1,629 120 1,749 Foreign corporate bonds and other debt securities — 678 103 781 Equity securities (3) Equity securities with readily determinable fair values 3,633 135 — 3,768 Equity securities measured at net asset value (2) 53 Other investments — — 35 35 Total assets measured at fair value on a recurring basis 22,753 17,629 1,941 43,007 Liabilities: Trading securities sold, not yet purchased 2,380 199 1 2,580 Derivative financial instruments: Interest rate contracts 38 5,564 8 5,610 Foreign exchange contracts 11 1,746 1 1,758 Equity-related contracts 82 51 9 142 Credit-related contracts — 16 1 17 Other contracts 1 4 9 14 Long-term debt (4) — 1,778 655 2,433 Total liabilities measured at fair value on a recurring basis 2,512 9,358 684 12,554 Notes: (1) Trading securities include foreign currency denominated securities for which the MHFG Group elected the fair value option. (2) 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, 2018 and 2019 were ¥31 billion and ¥37 billion, respectively. (3) The MHFG Group adopted ASU No.2016-01 available-for-sale (4) Amounts represent items for which the Group elected the fair value option or for which it applied the practicability exception. Items measured at fair value on a recurring basis using significant unobservable inputs (Level 3) The following table presents a reconciliation for all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the fiscal years ended March 31, 2018 and 2019: 2018 April 1, Gains Gains Transfers Transfers Purchases Sales Issuances Settle- March 31, 2018 Change in (losses) (6) (in billions of yen) Assets: Trading securities: Residential mortgage-backed securities 15 — (2) — — — — — — (3 ) 12 — Corporate bonds and 1,052 (20 ) (2) — 123 (241 ) 1,082 (631 ) — (352 ) 1,013 (19 ) Equity securities 23 (1 ) (2) — — — 2 (1 ) — — 23 — Derivative financial instruments, (1) Interest rate contracts 26 (6 ) (2) — — — — — — 1 21 (1 ) Foreign exchange contracts 8 2 (2) — — — — — — 2 12 5 Equity-related contracts (25 ) 1 (2) — — — — — — 28 4 12 Credit-related contracts — — (2) — — — — — — 1 1 — Other contracts — (1 ) (2) — — — — — — 1 — — Available-for-sale Residential mortgage-backed securities 77 — (3) — (4) — — 3 (6 ) — (20 ) 54 — Commercial mortgage-backed securities 224 — (3) 3 (4) — — 286 (69 ) — (3 ) 441 — Japanese corporate bonds and other debt securities 174 11 (3) (10 ) (4) — — 17 — — (29 ) 163 11 Foreign corporate bonds and other debt securities 110 — (3) (1 ) (4) 15 (46 ) 2 — — — 80 — Other investments 37 — (3) — — — 14 (3 ) — (10 ) 38 — Liabilities: Trading securities sold, not yet purchased — — (2) — — — (146 ) 150 — — 4 — Long-term debt 593 3 (5) — 1 (10 ) — — 151 (171 ) 561 5 2019 April 1, Gains Gains Transfers Transfers Purchases Sales Issuances Settle- March 31, 2019 Change in (losses) (6) (in billions of yen) Assets: Trading securities: Residential mortgage-backed securities 12 — (2) — — — — — — (1 ) 11 — Corporate bonds and 1,013 1 (2) — — — 762 (378 ) — (354 ) 1,044 8 Equity securities 23 1 (2) — — — 7 (3 ) — — 28 (1 ) Derivative financial instruments, net (1) Interest rate contracts 21 (11 ) (2) — — — — — — 3 13 (5 ) Foreign exchange contracts 12 15 (2) — — — — — — (5 ) 22 14 Equity-related contracts 4 (15 ) (2) — — — — — — 6 (5 ) 3 Credit-related contracts 1 (2 ) (2) — — — — — — 2 1 1 Other contracts — 1 (2) — — — — — — — 1 1 Available-for-sale Residential mortgage-backed securities 54 — (3) — (4) — — — — — (14 ) 40 — Commercial mortgage-backed securities 441 — (3) 1 (4) — — 144 (72 ) — (14 ) 500 — Japanese corporate bonds and other debt securities 163 37 (3) (33 ) (4) — — 29 (7 ) — (69 ) 120 19 Foreign corporate bonds and other debt securities 80 — (3) (1 ) (4) 61 (42 ) 27 — — (22 ) 103 — Other investments 38 5 (3) — — — 13 (6 ) — (15 ) 35 (2 ) Liabilities: Trading securities sold, not yet purchased 4 1 (2) — — — (35 ) 33 — — 1 — Long-term debt 561 (6 ) (5) 10 (4) 7 — — — 192 (101 ) 655 5 Notes: (1) Total Level 3 derivative exposures have been netted on the table for presentation purposes only. (2) Gains (losses) in Earnings are reported in Trading account gains (losses)—net, Foreign exchange gains (losses)—net or Other noninterest income (expenses). (3) Gains (losses) in Earnings are reported in Investment gains (losses)—net. (4) Gains (losses) in OCI are reported in Other comprehensive income (loss). (5) Gains (losses) in Earnings are reported in Other noninterest income (expenses). (6) Amounts represent total gains or losses recognized in earnings during the period. These gains or losses were attributable to the change in fair value relating to assets and liabilities classified as Level 3 that were still held at March 31, 2018 and 2019. Transfers between levels Transfers of assets or liabilities between levels of the fair value hierarchy are assumed to occur at the beginning of the period. During the fiscal year ended March 31, 2018, the transfers into Level 3 included ¥123 billion of Trading securities, ¥15 billion of Available-for-sale Available-for-sale Available-for-sale Available-for-sale During the fiscal year ended March 31, 2019, the transfers into Level 3 included ¥61 billion of Available-for-sale Available-for-sale Available-for-sale Available-for-sale Quantitative information about Level 3 fair value measurements The following table presents information about significant unobservable inputs related to the MHFG Group’s material classes of Level 3 assets and liabilities at March 31, 2018 and 2019: 2018 Products/Instruments Fair value Principal valuation technique Unobservable inputs Range of input values Weighted average (5) (in billions of yen, except for percentages and basis points) Trading securities and Available-for-sale Residential mortgage-backed securities 66 Discounted cash flow Prepayment rate 3%–17% 7% Price-based Default rate 0%–1% 0% Recovery rate 100%–100% 100% Discount margin 17bps–170bps 50bps Commercial mortgage-backed 441 Discounted cash flow Price-based Discount margin 9bps–141bps 28bps Corporate bonds and other debt 1,256 Discounted cash flow Prepayment rate (1) 26%–37% 36% Price-based Default rate (1) 1%–2% 2% Recovery rate (1) 60%–69% 68% Discount margin (1) 12bps–1,165bps 115bps Discount margin (2) 5bps–1,064bps 379bps Derivative financial instruments, net: Interest rate contracts 21 Internal valuation model (3) IR – IR correlation 23%–100% Default rate (4) 0%–63% Foreign exchange contracts 12 Internal valuation model (3) FX – IR correlation 16%–53% FX – FX correlation 61%–61% Default rate (4) 0%–63% Equity-related contracts 4 Internal valuation model (3) Equity – IR correlation 25%–25% Equity volatility 12%–41% Credit-related contracts 1 Internal valuation model (3) Default rate 0%–3% Credit correlation 27%–100% Long-term debt 561 Internal valuation model (3) IR – IR correlation 23%–100% FX – IR correlation 9%–53% FX – FX correlation 61%–61% Equity – IR correlation 25%–25% Equity – FX correlation 55%–70% Equity correlation 24%–100% Equity volatility 13%–56% Default rate 0%–2% Credit correlation 28%–100% 2019 Products/Instruments Fair value Principal valuation technique Unobservable inputs Range of input values Weighted average (5) (in billions of yen, except for percentages and basis points) Trading securities and Available-for-sale Residential mortgage- 51 Discounted cash flow Prepayment rate 4%–19% 8% Price-based Default rate 0%–1% 0% Recovery rate 100%–100% 100% Discount margin 18bps–170bps 51bps Commercial mortgage-backed 500 Discounted cash flow Price-based Discount margin 9bps–161bps 24bps Corporate bonds and other debt 1,267 Discounted cash flow Prepayment rate (1) 22%–22% 22% Price-based Default rate (1) 2%–2% 2% Recovery rate (1) 69%–69% 69% Discount margin (1) 48bps–1,173bps 134bps Discount margin (2) 4bps–1,063bps 295bps Derivative financial instruments, net: Interest rate contracts 13 Internal valuation model (3) IR – IR correlation 23%–100% Default rate (4) 0%–63% Foreign exchange contracts 22 Internal valuation model (3) FX – IR correlation 9%–55% FX – FX correlation 63%–63% Default rate (4) 0%–63% Equity-related contracts (5 ) Internal valuation model (3) Equity – IR correlation 25%–25% Equity correlation 40%–100% Equity volatility 5%–36% Credit-related contracts 1 Internal valuation model (3) Default rate 0%–5% Credit correlation 29%–100% Long-term debt 655 Internal valuation model (3) IR – IR correlation 23%–100% FX – IR correlation 9%–55% FX – FX correlation 63%–63% Equity – IR correlation 25%–25% Equity – FX correlation 55%–88% Equity correlation 12%–100% Equity volatility 5%–49% Default rate 0%–4% Credit correlation 20%–100% 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) This input represents the counterparty default rate derived from the MHFG Group’s own internal credit analyses. (5) Weighted averages are calculated by weighting each input by the relative fair value of the respective financial instruments. IR = Interest rate FX = Foreign exchange Sensitivities to unobservable inputs and interrelationships between unobservable inputs The following is a description of the sensitivities and 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 LIBOR 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, 2018 and 2019: 2018 Total Level 1 Level 2 Level 3 Aggregate cost (in billions of yen) Assets: Loans 113 — — 113 164 Loans held-for-sale 60 — 60 — 74 Equity securities (without readily determinable fair values) 1 — — 1 3 Premises and equipment—net — — — — 4 Total assets measured at fair value on a nonrecurring basis 174 — 60 114 245 2019 Total Level 1 Level 2 Level 3 Aggregate cost (in billions of yen) Assets: Loans 125 — 41 84 177 Loans held-for-sale 3 — 3 — 3 Equity securities (without readily determinable fair values) 1 — — 1 1 Other investments 98 98 — — 104 Premises and equipment—net 9 — 4 5 34 Intangible assets — — — — 1 Total assets measured at fair value on a nonrecurring basis 236 98 48 90 320 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 have been impaired and measured based upon the observable market price of the loan or the fair value of the underlying collateral. 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 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. Premises and equipment—net and Intangible assets in the table above have been impaired and written down to fair value. 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. On April 1, 2018, the Group adopted ASU No.2016-01. 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. 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. The differences between the aggregate fair value of these notes and the aggregate unpaid principal balance of such instruments were ¥21 billion and ¥21 billion at March 31, 2018 and 2019, respectively. The net unrealized gains (losses) resulting from changes in fair values of these notes recorded in Other noninterest income (expenses) were of ¥(15) billion and ¥(17) billion for the fiscal years ended March 31, 2018 and 2019, respectively. The Group records changes in fair value on these notes attributable to the instrument-specific credit risk in AOCI in accordance with ASU No.2016-01, Fair value of 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 impaired loans is determined based on the fair value of the underlying collateral. Other financial assets The carrying value of other financial assets, which primarily consist of accounts receivable from brokers, dealers, and customers for securities transactions, accrued income and collateral provided for derivative 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. The majority of other financial assets is classified as Level 2, and included in the table in Note 13 “Other assets and liabilities”. Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions The carrying value of short-term financial liabilities, such as noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions approximates the fair value of these liabilities since they generally have short-term maturities with interest rates that approximate market rates. Interest-bearing deposits The carrying value of demand deposits approximates the fair value since it represents the amount payable on demand at the balance sheet date. The fair value of time deposits and certificates of deposit is primarily estimated based on discounted cash flow analysis using current interest rates for instruments with similar maturities. The carrying value of short-term certificates of deposit approximates the fair value. Due to trust accounts The carrying value of due to trust accounts approximates the fair value since they generally have short-term maturities with interest rates that approximate market rates. Other short-term borrowings The carrying value of the majority of other short-term borrowings approximates the fair value since they generally have short-term maturities with interest rates that approximate market rates. The fair value of certain borrowings is estimated based on discounted cash flow analysis using interest rates approximating the MHFG Group’s incremental borrowing rates for instruments with similar maturities. Long-term debt Long-term debt is fair valued using quoted market prices, if available. Otherwise, the fair value of long-term debt is estimated based on discounted cash flow analysis using interest rates approximating the MHFG Group’s incremental borrowing rates for instruments with similar maturities. Other financial liabilities The carrying value of other financial liabilities, which primarily consist of accounts payable to brokers, dealers, and customers for securities transactions, accrued expenses and collateral accepted for derivative transactions, approximates the fair value since they generally have short-term maturities with interest rates that approximate market rates. The majority of other financial liabilities is classified as Level 2, and included in the table in Note 13 “Other assets and liabilities”. The fair value of certain off-balance-sheet The following table shows the carrying amounts and fair values at March 31, 2018 and 2019, of certain financial instruments, excluding financial instruments which are carried at

Offsetting of financial assets

Offsetting of financial assets and financial liabilities	12 Months Ended
	Mar. 31, 2019
Offsetting of financial assets and financial liabilities	29. 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, 2018 and 2019. 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 Net amounts presented on the (2) Financial instruments ( 4 ) Cash collateral Net (in billions of yen) 2018 Assets (1) Derivatives 9,341 — 9,341 (7,751 ) (520 ) 1,070 Receivables under resale agreements 7,804 — 7,804 (7,763 ) — 41 Receivables under securities borrowing transactions 3,904 — 3,904 (3,874 ) — 30 Total 21,049 — 21,049 (19,388 ) (520 ) 1,141 Liabilities (1) Derivatives 9,013 — 9,013 (7,758 ) (884 ) 371 Payables under repurchase agreements 15,964 — 15,964 (15,847 ) — 117 Payables under securities lending transactions 1,181 — 1,181 (1,179 ) — 2 Total 26,158 — 26,158 (24,784 ) (884 ) 490 2019 Assets (1) Derivatives 7,403 — 7,403 (5,903 ) (528 ) 972 Receivables under resale agreements 12,589 — 12,589 (12,579 ) — 10 Receivables under securities borrowing transactions 1,921 — 1,921 (1,894 ) — 27 Total 21,913 — 21,913 (20,376 ) (528 ) 1,009 Liabilities (1) Derivatives 6,978 — 6,978 (5,766 ) (769 ) 443 Payables under repurchase agreements 14,312 — 14,312 (14,309 ) — 3 Payables under securities lending transactions 932 — 932 (931 ) — 1 Total 22,222 — 22,222 (21,006 ) (769 ) 447 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.

Repurchase agreements and secur

Repurchase agreements and securities lending transactions accounted for as secured borrowings	12 Months Ended
	Mar. 31, 2019
Repurchase agreements and securities lending transactions accounted for as secured borrowings	30. 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, 2018 and 2019: Overnight and Up to 30 days 31-90 days Greater than Total (in billions of yen) 2018 Repurchase agreements 255 11,669 3,676 1,057 16,657 Securities lending transactions 1,270 355 — 208 1,833 Total 1,525 12,024 3,676 1,265 18,490 2019 Repurchase agreements 2,596 8,537 2,403 1,104 14,640 Securities lending transactions 1,012 473 — 313 1,798 Total 3,608 9,010 2,403 1,417 16,438 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, 2018 and 2019: Repurchase Securities lending (in billions of yen) 2018 Japanese government bonds and Japanese local government bonds 1,358 592 Foreign government bonds and foreign agency mortgage-backed securities 14,426 303 Commercial paper and corporate bonds 328 48 Equity securities 406 869 Other 139 21 Total (Note) 16,657 1,833 2019 Japanese government bonds and Japanese local government bonds 2,118 430 Foreign government bonds and foreign agency mortgage-backed securities 11,613 396 Commercial paper and corporate bonds 223 52 Equity securities 492 902 Other 194 18 Total (Note) 14,640 1,798 Note: Amounts exceeded the gross amounts recognized in Note 29 “Offsetting of financial assets and financial liabilities” by ¥1,345 billion and ¥1,194 billion, at March 31, 2018 and 2019, respectively, which excluded the amounts relating to master netting agreements or similar agreements where the MHFG Group did not have the legal right of set-off The MHFG Group is required to post securities as collateral with a fair value equal to or in excess of the principal amount of the cash borrowed under repurchase agreements. For securities lending transactions, the Group receives collateral in the form of cash. These contracts involve risks, including (1) the counterparty may fail to return the securities at maturity and (2) the fair value of the securities posted may decline below the amount of the Group’s obligation and therefore the counterparty may require additional amounts. The Group attempts to mitigate these risks by entering into transactions mainly with central counterparty clearing houses which revalue assets and perform margin maintenance activities on a regular basis, diversifying the maturities and counterparties, and using mainly highly liquid securities.

Related party transactions

Related party transactions	12 Months Ended
	Mar. 31, 2019
Related party transactions	31. Related party transactions The banking subsidiaries of MHFG make loans to the MHFG Group’s directors, executive officers, and other related parties. At March 31, 2018 and 2019, outstanding loans to such related parties were not considered significant. At March 31, 2018 and 2019, there were no loans to these related parties that were considered impaired.

Business segment information

Business segment information	12 Months Ended
	Mar. 31, 2019
Business segment information	32. Business segment information The MHFG Group consists of the following five in-house The services that each in-house Retail & Business Banking Company This company provides financial services for individual customers, small and medium-sized 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 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, MHFG (Consolidated) 2017 ( 4 ) Retail & Corporate & Global Global Asset Others (3) Total (in billions of yen) Gross profits + Net gains (losses) related to ETFs and others (1) 716.7 438.3 339.4 549.3 48.8 36.7 2,129.2 General and administrative expenses 719.3 199.9 239.2 191.2 29.3 31.4 1,410.3 Equity in earnings (losses) of equity method investees—net 14.9 1.0 0.9 — 0.5 1.6 18.9 Amortization of goodwill and others 0.4 0.4 0.4 2.3 4.0 2.7 10.2 Others — — — — — (27.7 ) (27.7 ) Net business profits (losses) (2) 11.9 239.0 100.7 355.8 16.0 (23.5 ) 699.9 MHFG (Consolidated) 2018 ( 4 ) Retail & Corporate & Global Global Asset Others ( 3) Total (in billions of yen) Gross profits + Net gains (losses) related to ETFs and others (1) 726.9 431.4 340.7 389.2 50.1 57.3 1,995.6 General and administrative expenses 724.8 202.5 250.9 201.2 27.6 37.2 1,444.2 Equity in earnings (losses) of equity method investees—net 12.7 1.0 2.3 — 2.9 2.6 21.5 Amortization of goodwill and others 0.4 0.4 0.4 2.3 8.0 2.4 13.9 Others — — — — — (21.0 ) (21.0 ) Net business profits (losses) (2) 14.4 229.5 91.7 185.7 17.4 (0.7 ) 538.0 MHFG (Consolidated) 2019 ( 4 ) Retail & Corporate & Global Global Asset Others (3) Total (in billions of yen) Gross profits + Net gains (losses) related to ETFs and others (1) 707.2 473.8 416.1 192.0 49.7 (11.1 ) 1,827.7 General and administrative expenses 713.7 198.2 251.8 203.3 27.3 46.3 1,440.6 Equity in earnings (losses) of equity method investees—net 18.1 0.9 7.3 — 1.3 23.6 51.2 Amortization of goodwill and others 0.4 0.4 0.4 2.3 8.0 2.1 13.6 Others — — — — — (16.3 ) (16.3 ) Net business profits (losses) (2) 11.2 276.1 171.2 (13.6 ) 15.7 (52.2 ) 408.4 Fixed assets ( 5 ) 499.3 225.8 176.9 92.6 0.1 662.5 1,657.2 Notes: (1) “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 and net gains (losses) on operating investment securities of MHSC on its consolidated basis. For the fiscal years ended March 31, 2017, 2018 and 2019, net gains related to ETFs and others amounted to ¥36.5 billion, ¥80.2 billion and ¥15.0 billion, respectively, of which ¥32.6 billion, ¥70.1 billion and ¥7.3 billion, respectively, are included in “Global Markets Company”. (2) Net business profits 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 plus equity in earnings (losses) of equity method investees—net and others. Measurement of net business profits is required for regulatory reporting to the Financial Services Agency. (3) “Others” includes items which should be eliminated as internal transactions between each segment on a consolidated basis. (4) Beginning on April 1, 2018, new allocation methods for income and expense transactions between each segment and “Others” have been applied. In connection with the use of the new allocation methods, the presentation of “Net business profits” has changed to “Net business profits (losses) + Net gains (losses) related to ETFs and others”. Before the change, “Net gains (losses) related to ETFs and others” were included in “Gross profits” of each segment and eliminated in “Others”. In addition, “Amortization of goodwill and others” has been presented as a new item. Figures for the fiscal years ended March 31, 2017 and 2018 have been restated for the new allocation methods. These changes more appropriately reflect the performance of each of the operating segments in accordance with internal managerial accounting rules and practices. Furthermore, income and expense of foreign branches of MHBK and foreign subsidiaries with functional currency other than Japanese Yen have been translated for purposes of segment reporting using the budgeted foreign currency rates. Prior period comparative amounts for these foreign currency income and expense have been translated using current period budgeted foreign currency rates. (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, 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, to the corresponding items in the accompanying consolidated statements of income. A reconciliation of “Net business profits (losses) + Net gains (losses) related to ETFs and others” for the fiscal years ended March 31, 2017, 2018 and 2019 presented above to income before income tax expense shown on the consolidated statements of income and a reconciliation of “Fixed assets” for the fiscal year ended March 31, 2019 to the total amount of Premises and equipment-net, 2017 2018 2019 (in billions of yen) Net business profits (losses) + Net gains (losses) related to ETFs and others 699.9 538.0 408.4 Adjustment to reconcile management reporting to Japanese GAAP: General and administrative expenses (non-recurring losses) (46.7 ) (30.9 ) 23.3 Expenses related to portfolio problems (including reversal of (provision for) general reserve for losses on loans) (80.2 ) (17.0 ) (30.7 ) Gains on reversal of reserves for possible losses on loans, and others 32.7 173.3 11.2 Net gains (losses) related to stocks - Net gains (losses) related to ETFs and others 205.7 191.9 259.9 Net extraordinary gains (losses) 46.7 17.5 (497.9 ) Others (73.9 ) (72.8 ) (57.9 ) Income before income tax expense under Japanese GAAP 784.2 800.0 116.3 Adjustment to reconcile Japanese GAAP to U.S. GAAP: Derivative financial instruments and hedging activities (221.9 ) (110.2 ) 45.3 Investments (115.9 ) 98.1 (273.3 ) Loans 2.5 (2.4 ) (11.9 ) Allowances for loan losses and off-balance-sheet instruments (13.8 ) 6.8 (5.8 ) Premises and equipment 28.6 35.4 303.6 Land revaluation 4.5 3.4 10.2 Business combinations 14.8 15.6 (12.8 ) Pension liabilities 33.8 (4.4 ) (32.2 ) Consolidation of variable interest entities 1.6 2.7 (39.0 ) Foreign currency translation (6.2 ) 12.1 1.7 Others (31.8 ) (17.8 ) (17.0 ) Income before income tax expense under U.S. GAAP 480.4 839.3 85.1 2019 (in billions of yen) Fixed assets 1,657.2 U.S. GAAP adjustments 413.1 Premises and equipment-net, Goodwill, and Intangible assets 2,070.3 Note: The U.S. GAAP adjustments are primarily comprised of GAAP differences mainly from internally developed software, which was impaired under Japanese GAAP; land, which was revalued under Japanese GAAP; and the consolidation of certain variable interest entities, which are not consolidated under Japanese GAAP.

Foreign activities

Foreign activities	12 Months Ended
	Mar. 31, 2019
Foreign activities	33. Foreign activities The following table presents consolidated income statement and total assets information by major geographic area. Foreign activities are defined as business transactions that involve customers residing outside of Japan. However, as the MHFG Group’s operations are highly integrated globally, estimates and assumptions have been made for an allocation among the geographic areas. Americas Japan United Others Europe Asia/Oceania and others Total (in billions of yen) Fiscal year ended March 31, 2017: Total revenue (1) 1,748.3 500.3 70.3 190.7 367.5 2,877.1 Total expenses (2) 1,712.3 303.2 29.1 136.2 215.9 2,396.7 Income before income tax expense 36.0 197.1 41.2 54.5 151.6 480.4 Net income 5.7 167.6 38.8 39.5 137.5 389.1 Total assets at end of fiscal year 138,832.3 30,262.0 4,203.3 10,629.1 16,529.6 200,456.3 Fiscal year ended March 31, 2018: Total revenue (1) 2,002.4 654.9 64.0 197.4 447.8 3,366.5 Total expenses (2) 1,582.5 478.8 38.5 172.6 254.8 2,527.2 Income before income tax expense 419.9 176.1 25.5 24.8 193.0 839.3 Net income 231.3 152.7 23.7 21.3 172.7 601.7 Total assets at end of fiscal year 142,587.8 28,135.9 4,380.4 11,677.8 17,473.7 204,255.6 Fiscal year ended March 31, 2019: Total revenue (1) 1,705.5 792.1 66.0 249.7 616.5 3,429.8 Total expenses (2) 2,082.6 696.5 46.1 203.2 316.3 3,344.7 Income before income tax expense (377.1 ) 95.6 19.9 46.5 300.2 85.1 Net income (331.4 ) 85.3 17.0 34.6 270.2 75.7 Total assets at end of fiscal year 133,443.5 25,913.5 4,824.7 15,322.5 18,107.0 197,611.2 Notes: (1) Total revenue is comprised of Interest and dividend income and Noninterest income. (2) Total expenses are comprised of Interest expense, Provision (credit) for loan losses and Noninterest expenses.

Mizuho Financial Group, Inc., p

Mizuho Financial Group, Inc., parent company	12 Months Ended
	Mar. 31, 2019
Mizuho Financial Group, Inc., parent company	34. Mizuho Financial Group, Inc., parent company The following tables present the parent company only financial information of MHFG: Condensed balance sheets 2018 2019 (in millions of yen) Assets: Cash and due from banks 22,264 99,209 Interest-bearing deposits in other banks 1,227 1,158 Trading account assets 176,593 — Investments in subsidiaries and affiliated companies 9,501,633 9,317,387 Long-term loans receivable from subsidiaries 3,969,015 5,110,248 Other 344,065 351,951 Total 14,014,797 14,879,953 Liabilities and shareholders’ equity: Short-term borrowings 1,083,135 945,505 Long-term debt 3,969,015 5,145,286 Other liabilities 94,226 62,643 Shareholders’ equity 8,868,421 8,726,519 Total 14,014,797 14,879,953 Condensed statements of income 2017 2018 2019 (in millions of yen) Income: Dividends from subsidiaries and affiliated companies: Banking subsidiaries 300,530 227,057 267,724 Non-banking 27,618 28,987 23,392 Management fees from subsidiaries 48,594 47,945 39,292 Interest income on loans and discounts 39,359 68,869 106,920 Other income 21,054 52,672 9,575 Total 437,155 425,530 446,903 Expenses: Operating expenses 38,927 38,661 40,680 Interest expense 48,594 74,227 110,861 Other expense 14,608 28,123 59,049 Total 102,129 141,011 210,590 Equity in undistributed net income (loss) of subsidiaries 32,595 309,210 (173,142 ) Income before income tax expense 367,621 593,729 63,171 Income tax expense (benefit) 5,181 16,121 (21,300 ) Net income 362,440 577,608 84,471 Condensed statements of cash flows 2017 2018 2019 (in millions of yen) Cash flows from operating activities: Net income 362,440 577,608 84,471 Adjustments and other (40,595 ) (302,109 ) 197,193 Net cash provided by operating activities 321,845 275,499 281,664 Cash flows from investing activities: Proceeds from sales of Equity securities — — 139,719 Net change in loans (2,022,860 ) (1,344,323 ) (1,075,059 ) Purchases of premises and equipment (40,362 ) (6,649 ) (11,640 ) Payments for purchases of securities of subsidiaries (65,269 ) — — Proceeds from withdrawal of securities of subsidiaries 13,359 — — Net change in other investing activities (5,336 ) (4,114 ) (1,310 ) Net cash used in investing activities (2,120,468 ) (1,355,086 ) (948,290 ) Cash flows from financing activities: Net change in short-term borrowings (30,000 ) (70,000 ) (140,000 ) Proceeds from issuance of long-term debt 2,022,860 1,344,323 1,075,059 Proceeds from issuance of common stock 6 3 3 Purchases of treasury stock (1,435 ) (1,611 ) (2,124 ) Dividends paid (190,031 ) (190,382 ) (190,413 ) Net change in other financing activities 971 555 437 Net cash provided by financing activities 1,802,371 1,082,888 742,962 Effect of exchange rate changes on cash and cash equivalents — — 540 Net increase (decrease) in cash and cash equivalents 3,748 3,301 76,876 Cash and cash equivalents at beginning of period 16,442 20,190 23,491 Cash and cash equivalents at end of period 20,190 23,491 100,367

Subsequent events

Subsequent events	12 Months Ended
	Mar. 31, 2019
Subsequent events	35. Subsequent events Redemption of preferred securities On June 30, 2019, preferred securities, issued by the MHFG Group’s overseas special purpose company, were redeemed in full. The special purpose company is not consolidated in accordance with ASC 810 since the Group is not the primary beneficiary. Thus, the redemption of preferred securities did not reduce Noncontrolling interests in consolidated subsidiaries, but reduced Long-term debt in the Group’s consolidated balance sheets. The following table describes the details of the redeemed preferred securities: Issuer Aggregate redemption amount Reason for the redemption (in millions) Mizuho Capital Investment (JPY) 3 Limited Series A ¥249,500 Arrival of optional redemption date Mizuho Capital Investment (JPY) 3 Limited Series B ¥53,500 Arrival of optional redemption date

Basis of presentation and sum_2

Basis of presentation and summary of significant accounting policies (Policies)	12 Months Ended
	Mar. 31, 2019
Basis of presentation	Basis of presentation Mizuho Financial Group, Inc. (“MHFG”) is a joint stock corporation with limited liability under the laws of Japan. MHFG is a holding company for Mizuho Bank, Ltd. (“MHBK”), Mizuho Trust & Banking Co., Ltd. (“MHTB”), Mizuho Securities Co., Ltd. (“MHSC”), Asset Management One Co., Ltd. (“Asset Management One”), and other subsidiaries. MHFG, through its subsidiaries (“the MHFG Group”, or “the Group”), provides domestic and international financial services in Japan and other countries. The MHFG Group has introduced an in-house MHFG and its domestic subsidiaries as well as its foreign subsidiaries maintain their accounting records in accordance with the accounting standards of Japan and those standards of the countries in which they are domiciled. Certain adjustments and reclassifications have been incorporated in the accompanying consolidated financial statements to conform them to the accounting principles generally accepted in the United States of America (“U.S. GAAP”). The consolidated financial statements are stated in Japanese yen, the currency of the country in which MHFG is incorporated and principally operates. The accompanying consolidated financial statements include the accounts of MHFG and its subsidiaries. MHFG’s fiscal year ends on March 31 and the fiscal year of certain subsidiaries ends on December 31. When determining whether to consolidate investee entities, the MHFG Group performed 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 the 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. The amounts of asset management business fee income and expenses for the fiscal year ended March 31, 2017 have been reclassified from Other noninterest income and Other noninterest expenses to Fee and commission income and Fee and commission expenses, respectively, in order to conform to the current period’s presentation. Such reclassifications had no effect on net income or shareholders’ equity. In addition, certain other comparative amounts for the prior period have been reclassified in order to conform to the current period’s presentation.
Use of estimates	Use of estimates The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect reported amounts and related disclosures. Specific areas, among others, requiring the application of management’s estimates and judgment include assumptions pertaining to the allowance for loan losses, allowance for losses on off-balance-sheet
Deconsolidation of TCSB	Deconsolidation of TCSB In March 2018, Trust & Custody Services Bank, Ltd. (“TCSB”), MHFG’s former subsidiary, and Japan Trustee Services Bank, Ltd. (“JTSB”) entered into a management integration agreement. Based on the agreement, TCSB and JTSB incorporated a holding company, JTC Holdings, Ltd. (“JTC Holdings”) through joint share transfer on October 1, 2018, and became wholly-owned subsidiaries of JTC Holdings on that date. Starting October 1, 2018, MHFG has no longer consolidated TCSB, which had approximately ¥14 trillion and ¥9 trillion, respectively, in total assets as of March 31, 2018 and September 30, 2018. However, MHFG has maintained 27.0% of the voting equity interests in JTC Holdings and accounted for this investment using the equity method of accounting. There was no material effect from TCSB deconsolidation on the accompanying consolidated statement of income for the year ended March 31, 2019.
Definition of cash and cash equivalents	Definition of cash and cash equivalents For purposes of the consolidated statements of cash flows, Cash and cash equivalents consists of Cash and due from banks and Interest-bearing deposits in other banks. Cash deposited with central banks that must be maintained to meet minimum regulatory requirements is classified as restricted cash and included in Cash and cash equivalents. See Note 9 “Pledged assets and collateral” for more information on restricted cash. The MHFG Group adopted ASU No.2016-18, No.2016-18”) No.2016-18,
Translation of foreign currency financial statements and foreign currency transactions	Translation of foreign currency financial statements and foreign currency transactions Financial statements of overseas entities are prepared using the functional currency of each entity and translated into Japanese yen for consolidation purposes. Assets and liabilities are translated using the fiscal-year-end Foreign currency translation gains and losses related to the financial statements of overseas entities of the MHFG Group, net of related income tax effects, are credited or charged directly to Foreign currency translation adjustments, a component of Accumulated other comprehensive income, net of tax (“AOCI”). The tax effects of gains and losses related to the foreign currency translation of financial statements of overseas entities are not recognized unless it is apparent that the temporary differences will reverse in the foreseeable future. Assets and liabilities of domestic and overseas entities denominated in foreign currencies are remeasured into the functional currency of the respective entity at the fiscal year-end
Call loans and call money	Call loans and call money Call loans and call money represent lending/borrowing, primarily through the Japanese short-term money market, to/from other financial institutions such as banks, insurance companies, and securities brokerage houses.
Repurchase and resale agreements, securities lending and borrowing and other secured financing transactions	Repurchase and resale agreements, securities lending and borrowing and other secured financing transactions Securities sold under agreements to repurchase (“repurchase agreements”), securities purchased under agreements to resell (“resale agreements”) and securities lending and borrowing transactions are accounted for as secured financing or lending transactions when control over the underlying securities is not deemed to be surrendered by the transferor. Otherwise, they are recorded as sales of securities with related forward repurchase commitments or purchases of securities with related forward resale commitments in accordance with ASC 860, “Transfers and Servicing” (“ASC 860”). Under resale agreements, securities borrowing and certain derivatives transactions, the MHFG Group receives collateral in the form of securities. In many cases, the MHFG Group is permitted to sell or repledge the securities obtained as collateral. Disclosures in respect of such collateral are presented in Note 9 “Pledged assets and collateral”. With respect to repurchase agreements, securities lending, and certain derivative transactions, counterparties may have the right to sell or repledge securities that the MHFG Group has pledged as collateral. The MHFG Group separately discloses these pledged securities in the consolidated balance sheets. The MHFG Group monitors credit exposure arising from resale agreements, repurchase agreements, securities borrowing and securities lending transactions on a regular basis, and additional collateral is obtained from or returned to counterparties, as appropriate.
Trading securities and trading securities sold, not yet purchased	Trading securities and trading securities sold, not yet purchased Trading securities consist of securities and money market instruments that are bought and held principally for the purpose of reselling in the near term with the objective of generating profits on short-term fluctuations in price. Trading securities sold, not yet purchased, are securities and money market instruments sold to third parties that the MHFG Group does not own and is obligated to purchase at a later date to cover the short position. Trading securities and trading securities sold, not yet purchased, are recorded on the trade date. Trading securities and trading securities sold, not yet purchased, are recorded at fair value in the consolidated balance sheets in Trading account assets and Trading account liabilities with realized and unrealized gains and losses recorded on a trade date basis in Trading account gains (losses)—net in the consolidated statements of income. Interest and dividends on trading securities, including securities sold, not yet purchased, are recorded in Interest and dividend income or Interest expense on an accrual basis.
Investments	Investments Debt securities that the MHFG Group has both the positive intent and ability to hold to maturity are classified as Held-to-maturity Available-for-sale The credit component of an other-than-temporary impairment of a debt security is reported in Investment gains (losses)—net, and the noncredit component is reported in Other comprehensive income (loss). See Note 4 “Investments” for further discussion of impairment. Interest and dividends, as well as amortization of premiums and accretion of discounts, are reported in Interest and dividend income. Amortization of premiums and accretion of discounts on debt securities are recognized over their remaining maturities under the interest method. Gains and losses on disposition of investments are computed using the first-in first-out Other investments include marketable and non-marketable non-marketable
Derivative financial instruments	Derivative financial instruments Derivative financial instruments are bought and held principally for the purpose of market making for customers, proprietary trading in order to generate trading revenues and fee income, and also to manage the MHFG Group’s exposure to interest rate, credit and market risks related to asset and liability management. Such derivative financial instruments include interest rate, foreign currency, equity, commodity and credit default swap agreements, options, caps and floors, and financial futures and forward contracts. Derivatives bought and held for trading purposes are recorded in the consolidated balance sheets at fair value in Trading account assets and Trading account liabilities. The fair values of derivatives in a gain position and a loss position are reported as Trading account assets and Trading account liabilities, respectively. Derivatives used for asset and liability management include contracts that qualify for hedge accounting under ASC 815, “Derivatives and Hedging” (“ASC 815”). To be eligible for hedge accounting, derivative instruments must be highly effective in achieving offsetting changes in fair values or variable cash flows of the hedged items attributable to the particular risk being hedged. All qualifying hedging derivatives are valued at fair value and included in Trading account assets or Trading account liabilities. Derivatives that do not qualify for hedge accounting under ASC 815 are treated as trading positions and are accounted for as such. The fair value amounts recognized for all derivatives are presented on a gross basis and not offset against the amounts recognized for the right to reclaim cash collateral or the obligation to return cash collateral under the master netting agreement with the same counterparty. The fair values of derivative financial instruments are determined based on quoted market prices or broker-dealer quotes, if available. If not available, the fair values are estimated using quoted market prices for similar instruments, option or binomial pricing models or a present value cash flow analysis, utilizing current observable market information, where available. In determining the fair values, the Group considers various factors such as exchange or over-the-counter Changes in the fair values of all derivatives are recorded in earnings, except for derivatives qualifying as net investment hedges under ASC 815 which are recorded in AOCI. The changes in the fair values of all derivatives relating to foreign currency exchange rates are included in Foreign exchange gains (losses)—net and Trading account gains (losses)—net. Other elements of the changes in the fair values, including interest rate, equity and credit related components, except these of certain credit derivatives hedging the credit risk in the corporate loan portfolio, are recognized in Trading account gains (losses)—net. The net gain (loss) resulting from changes in the fair values of certain credit derivatives where the Group purchases protection to mitigate its credit risk exposure related to its corporate loan portfolio is recorded in Other noninterest income (expenses). Certain financial and hybrid instruments often contain embedded derivative instruments that possess implicit or explicit contract terms similar to those of a derivative instrument. Such derivative instruments are required to be fair-valued separately from the host contracts if they meet the bifurcation criteria of an embedded derivative. Such criteria include that the entire instrument is not marked to market through earnings, the economic characteristics and risks of the embedded contract terms are not clearly and closely related to those of the host contract and the embedded contract terms would meet the definition of a derivative on a stand-alone basis.
Loans	Loans Loans are generally carried at the principal amount adjusted for unearned income and deferred net nonrefundable loan fees and costs. Loan origination fees, net of certain direct origination costs, are deferred and recognized over the contractual life of the loan as an adjustment of yield using a method that approximates the interest method. Interest income on performing loans is accrued and credited to income as it is earned. Unearned income and discounts or premiums on purchased loans are deferred and recognized over the life of the loan using a method that approximates the interest method. Loans are considered impaired 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 impaired include delinquency status and the ability of the debtor to make payments of the principal and interest when due. Impaired loans include loans past due for 90 days or more and restructured loans that meet the definition of a troubled debt restructuring (“TDR”) in accordance with ASC 310, “Receivables” (“ASC 310”). All of the MHFG Group’s impaired loans are designated as nonaccrual loans and thus 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 collectibility 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. Impaired loans are restored to non-impaired non-impaired Loans that have been identified for sale are classified as loans held for sale within Other assets and are accounted for at the lower of cost or fair value on an individual loan basis. If management decides to retain certain loans held for sale for the foreseeable future or until maturity or payoff, such items are transferred to Loans at the lower of cost or fair value.
Allowance and provision (credit) for loan losses	Allowance and provision (credit) for loan losses The MHFG Group maintains an appropriate allowance for loan losses to absorb probable losses inherent in the loan portfolio and makes adjustments to such allowance through Provision (credit) for loan losses in the consolidated statements of income. Loan principal that management judges to be uncollectible, based on detailed loan reviews and a credit quality assessment, is charged off against the allowance for loan losses. In general, the MHFG Group charges off loans when the Group determines that the obligor should be classified as substantially bankrupt or bankrupt. See Note 5 “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 and other portfolio segments, the Group separately monitors the credit quality of each obligor without using time-based triggers. Subsequent recoveries of previously charged-off For the corporate portfolio segment, the credit quality review process and the credit rating process serve as the basis for determining the allowance for loan losses. 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 loan losses. MHFG Group’s accounting policies and the methodology used to estimate the allowance for loan losses for the other portfolio segment are equivalent to the policies and methodology used for the corporate portfolio segment. The allowance for loan losses is determined in accordance with ASC 310 and ASC 450, “Contingencies” (“ASC 450”). The MHFG Group measures the impairment of a loan when it is probable that the Group will be unable to collect all amounts due according to the contractual terms of the loan agreement, 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, or (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 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 formula allowance is applied to groups of loans that are collectively evaluated for impairment. The evaluation of the inherent loss in respect of these loans involves a high degree of uncertainty, subjectivity and judgment because probable loan losses are not easily identifiable or measurable. In determining the formula allowance, the MHFG Group therefore relies on a statistical analysis that incorporates loss rates based on its own historical loss experience and third-party data such as the number of corporate default cases which is updated once a year. In determining the allowance amount, the Group analyzes (1) the probability of default: (a) by using the most recently available data from April 2008 for the corporate portfolio segment, and the most recently available data for the past six years for the retail portfolio segment, in the case of normal obligors; and (b) by using the most recently available data from April 2002 for the corporate and retail portfolio segments, in the case of watch obligors; and (2) the loss given default by using the most recently available data for the past six years for the corporate and retail portfolio segments. As it pertains to TDR loans in the retail portfolio segment, which are subject to collective evaluation for impairment, the restructuring itself, as well as subsequent payment defaults, if any, are considered in determining obligor categories. The historical loss rate is adjusted, where appropriate, to reflect current factors, such as general economic and business conditions affecting the key lending areas of the MHFG Group, credit quality trends, specific industry conditions by portfolio segments, and recent loss experience in particular segments of the portfolio. When determining the length of the period to calculate the probability of default, the Group considers the uncertainty in the economic and business conditions. The estimation of the formula allowance is back-tested on a periodic basis by comparing the allowance with the actual results subsequent to the balance sheet date.
Allowance and provision (credit) for losses on off-balance-sheet instruments	Allowance and provision (credit) for losses on off-balance-sheet The MHFG Group maintains an allowance for losses on off-balance-sheet off-balance-sheet off-balance-sheet
Premises and equipment	Premises and equipment Premises and equipment are stated at historical cost, and depreciation and amortization are recorded over the estimated useful lives of the assets, except for leasehold improvements, which are amortized over the shorter of the estimated useful lives of the assets or the lease term. Depreciation and amortization are principally computed in accordance with the straight-line method with respect to buildings and leasehold improvements and in accordance with the declining-balance method with respect to other premises and equipment. The useful lives of premises and equipment are as follows: Years Buildings 3 to 50 Equipment and furniture 2 to 20 Leasehold improvements 3 to 50 Regular repairs and maintenance costs that do not extend the estimated useful life of an asset are charged to expense as incurred. Upon sale or disposition of premises and equipment, the cost and related accumulated depreciation or amortization are removed from the accounts, and any gains or losses on disposal are included in Gains on disposal of premises and equipment or Occupancy expenses.
Impairment of long-lived assets	Impairment of long-lived assets The MHFG Group’s long-lived assets that are held for use are reviewed periodically for events or changes in circumstances that indicate possible impairment. The Group’s impairment review is based on an undiscounted cash flow analysis of a group of assets, combined with associated liabilities, at the lowest level for which identifiable cash flows exist. Impairment occurs when the carrying value of the asset group exceeds the future undiscounted cash flows that the asset group is expected to generate. When impairment is identified, the future cash flows are then discounted to determine the estimated fair value of the asset group and an impairment charge is recorded for the difference between the carrying value and the estimated fair value of the asset group. The long-lived assets to be disposed of by sale are carried at the lower of the carrying amount or fair value, less estimated cost to sell.
Software	Software Internal and external costs incurred in connection with developing and obtaining software for internal use during the application development stage are capitalized. Such costs include salaries and benefits for employees directly involved with and who devote time to the project, to the extent such time is incurred directly on the internal use software project. The capitalization of software ceases when the software project has been substantially completed. The capitalized software is amortized on a straight-line basis over the estimated useful life, generally 5 to 10 years. Internal use software is reviewed for impairment whenever events or changes in circumstances indicate that its carrying amount may not be recoverable.
Goodwill	Goodwill Goodwill represents the excess of the total fair value of the acquired company, which consists of the consideration transferred, the fair value of any interest in the acquiree already held by the acquirer and the fair value of any noncontrolling interest in the acquiree over the fair value of net identifiable assets acquired at the date of acquisition in a business combination. The MHFG Group accounts for goodwill in accordance with ASC 350, “Intangibles—Goodwill and Other” (“ASC 350”). Goodwill is recorded at a designated reporting unit level for the purpose of assessing impairment. Goodwill is not amortized but is tested for impairment at least annually or more often if events or circumstances indicate there may be impairment. For both the annual and interim tests, the Group has the option to either (a) perform a quantitative impairment test or (b) first perform a qualitative assessment to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount, in which case the Group would perform the quantitative test. An impairment loss is recorded to the extent the carrying amount of goodwill exceeds its estimated fair value. The estimated fair value of the reporting units is derived based on valuation techniques that the Group believes market participants would use for each of the reporting units. The Group generally determines the estimated fair value by utilizing a discounted cash flow methodology or methodologies that incorporate price-to-book
Intangible assets	Intangible assets Intangible assets having definite useful lives are amortized over their estimated useful lives on either a straight-line basis or the method that reflects the pattern in which the economic benefits of the intangible assets are consumed. Intangible assets acquired in connection with the merger of MHSC and Shinko Securities Co., Ltd. (“Shinko”) and the integration among asset management companies consist primarily of customer relationship intangibles, and are amortized over weighted-average amortization periods of 16 years and 16.9 years, respectively. See Note 3 “Business Combination” for further details of the integration among asset management companies. Intangible assets having indefinite useful lives are not amortized and are subject to impairment tests. An impairment loss is recorded to the extent that the carrying amount of the indefinite-lived intangible asset exceeds its estimated fair value. For intangible assets subject to amortization, an impairment loss is recorded if the carrying amount is not recoverable and exceeds its estimated fair value.
Pension and other employee benefits	Pension and other employee benefits MHFG and certain subsidiaries sponsor severance indemnities and pension plans, which provide defined benefits to retired employees. Periodic expense and accrued liabilities are computed based on the actuarial present value of benefits, net of investment returns expected from plan assets and their fair values at the balance sheet date. Net periodic expense is charged to Salaries and employee benefits. Net actuarial gains and losses that arise from differences between actual experience and assumptions are generally amortized over the average remaining service period of participating employees if they exceed the corridor, which is defined as the greater of 10% of plan assets or the projected benefit obligation.
Stock-based compensation	Stock-based compensation MHFG, MHBK, MHTB and MHSC have a position-based stock compensation program for Directors (“Stock Compensation I”) and a performance-based stock compensation program for Directors (“Stock Compensation II”). For both programs, the stock-based compensation cost is determined based on the fair value of MHFG’s common stock as of grant date. For Stock Compensation I and II, the liability related to the cash-based compensation cost is remeasured at each reporting date based on the fair value of MHFG’s common stock. For Stock Compensation II, the stock-based compensation costs are recognized evenly over the graded-vesting period, which is three years. For Stock Compensation I, as the program is effectively vested on the grant date, the stock-based compensation cost is recognized on the grant date. See Note 22 “Stock-based compensation” for further details of the stock options and the stock compensation programs.
Long-term debt	Long-term debt Premiums, discounts and issuance costs of long-term debt are amortized based on a method that approximates the interest method over the respective terms of the long-term debt.
Obligations under guarantees	Obligations under guarantees The MHFG Group provides customers with a variety of guarantees and similar arrangements, including standby letters of credit, financial and performance guarantees, credit protection, and liquidity facilities. The MHFG Group recognizes guarantee fee income over the guarantee period. The MHFG Group receives such a guarantee fee at the inception of the guarantee or in installments and, in either case, the present value of the total fees approximates the fair value of the guarantee.
Fair Value Measurements	Fair Value Measurements The MHFG Group carries certain of its financial assets and liabilities at fair value on a recurring basis. These financial assets and liabilities are primarily composed of trading account assets, trading account liabilities and available-for-sale non-recurring Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. In accordance with ASC 820, “Fair Value Measurement” (“ASC 820”), the Group classifies its financial assets and liabilities into the fair value hierarchy (Level 1, 2, and 3). See Note 28 “Fair value” for the detailed definition of each level. When determining fair value, the MHFG Group considers the principal or most advantageous market in which the Group would transact and considers assumptions that market participants would use when pricing the asset or liability. The Group maximizes the use of observable inputs and minimizes the use of unobservable inputs when measuring fair value. See Note 28 “Fair value” for descriptions of valuation methodologies used for its assets and liabilities by product.
Fee and commission income	Fee and commission income The MHFG Group recognizes revenue from contracts with customers in an amount that reflects the consideration to which the Group expects to be entitled in exchange for transferring control of a promised service. The timing of revenue recognition is dependent on whether the Group satisfies a performance obligation by transferring control of the service to a customer over time or at a point in time. See Note 26 “Noninterest income” for further details of major components of Fee and commission income. Fee and commission income is presented exclusive of consumption taxes.
Income taxes	Income taxes Income taxes are accounted for in accordance with ASC 740, “Income Taxes” (“ASC 740”). Deferred income taxes reflect the net tax effects of (1) temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the corresponding amounts used for income tax purposes, and (2) operating loss and tax credit carryforwards. A valuation allowance is recorded for any portion of the deferred tax assets unless it is more likely than not that the deferred tax assets will be realized. Deferred income tax benefit or expense is recognized for the changes in the net deferred tax asset or liability between periods.
Earnings per common share	Earnings per common share Basic earnings per common share are computed by dividing net income attributable to MHFG common shareholders by the weighted average number of common shares outstanding during the fiscal year. Diluted earnings per common share reflect all dilutive potential common shares such as stock options and convertible preferred stock. See Note 19 “Earnings per common share” for the computation of basic and diluted earnings per common share.

Basis of presentation and sum_3

Basis of presentation and summary of significant accounting policies (Tables)	12 Months Ended
	Mar. 31, 2019
Useful Lives of Premises and Equipment	The useful lives of premises and equipment are as follows: Years Buildings 3 to 50 Equipment and furniture 2 to 20 Leasehold improvements 3 to 50

Business combination (Tables)

Business combination (Tables)	12 Months Ended
	Mar. 31, 2019
Summary of Consideration Paid for DIAM, Amounts of Acquired Assets and Assumed Liabilities Recognized and Fair Value of Noncontrolling Interest at Acquisition Date in DIAM	The following table summarizes the consideration paid for DIAM and the amounts of the acquired assets and assumed liabilities recognized at the acquisition date, as well as the fair value at the acquisition date of the noncontrolling interest in DIAM. There were no material acquisition-related costs that were recognized separately from the acquisition of the assets and the assumption of the liabilities. At October 1, (in millions of yen) Consideration: Equity instruments (1,038,408 common shares of MHAM) 28,842 Fair value of total consideration transferred 28,842 Fair value of equity interests in DIAM held by MHFG before the business combination 72,106 100,948 Recognized amounts of identifiable assets acquired: Cash and due from banks 831 Interest-bearing deposits in other banks 12,873 Trading account assets 266 Investments 12,234 Premises and equipment-net 3,546 Accrued income 7,882 Intangible assets (Note) 53,037 Deferred tax assets 1,003 Other assets 2,208 Recognized amounts of identifiable liabilities assumed: Trading account liabilities 304 Income taxes payable 918 Deferred taxes liabilities 16,238 Accrued expenses 5,392 Other liabilities 3,041 Total identifiable net assets 67,987 Goodwill 76,225 Noncontrolling interest in DIAM 43,264 100,948 Note: Amount represents customer relationships subject to amortization, of which the weighted-average amortization period is 16.9 years.

Investments (Tables)

Investments (Tables)	12 Months Ended
	Mar. 31, 2019
Amortized Cost, Gross Unrealized Gains and Losses, and Fair Value of Available-for-Sale and Held-to-Maturity Securities	The amortized cost, gross unrealized gains and losses, and fair value of available-for-sale held-to-maturity Amortized cost Gross unrealized Gross unrealized Fair value (in millions of yen) 2018 Available-for-sale Debt securities: Japanese government bonds 13,334,619 7,332 9,656 13,332,295 Japanese local government bonds 236,711 2,903 280 239,334 U.S. Treasury bonds and federal agency securities 689,297 109 3,557 685,849 Other foreign government bonds 1,057,852 1,043 1,102 1,057,793 Agency mortgage-backed securities (1) 882,686 13,356 7,628 888,414 Residential mortgage-backed securities 117,870 1,264 281 118,853 Commercial mortgage-backed securities 437,115 4,132 323 440,924 Japanese corporate bonds and other debt securities (2) 1,950,947 40,290 1,410 1,989,827 Foreign corporate bonds and other debt securities (3) 879,506 1,927 2,082 879,351 Equity securities (marketable) (4) 1,595,106 2,449,173 11,291 4,032,988 Total 21,181,709 2,521,529 37,610 23,665,628 Held-to-maturity Debt securities: Japanese government bonds 1,959,910 24,472 — 1,984,382 Agency mortgage-backed securities (5) 557,641 — 20,177 537,464 Total 2,517,551 24,472 20,177 2,521,846 Amortized cost Gross unrealized Gross unrealized Fair value (in millions of yen) 2019 Available-for-sale Debt securities: Japanese government bonds 11,888,510 11,259 2,998 11,896,771 Japanese local government bonds 208,308 1,671 87 209,892 U.S. Treasury bonds and federal agency securities 1,008,903 644 231 1,009,316 Other foreign government bonds 1,341,564 758 455 1,341,867 Agency mortgage-backed securities (1) 530,540 14,524 593 544,471 Residential mortgage-backed securities 99,904 1,420 191 101,133 Commercial mortgage-backed securities 495,313 4,914 104 500,123 Japanese corporate bonds and other debt securities (2) 1,743,309 7,686 1,561 1,749,434 Foreign corporate bonds and other debt securities (3) 778,088 3,047 226 780,909 Equity securities (marketable) (4) — — — — Total 18,094,439 45,923 6,446 18,133,916 Held-to-maturity Debt securities: Japanese government bonds 1,119,899 19,907 — 1,139,806 Agency mortgage-backed securities (5) 484,205 — 14,423 469,782 Total 1,604,104 19,907 14,423 1,609,588 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 ¥742,565 million and ¥145,849 million, respectively, at March 31, 2018, and ¥517,330 million and ¥27,141 million, respectively, at March 31, 2019. All Japanese agency mortgage-backed securities are issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise. Foreign agency mortgage-backed securities primarily consist of Government National Mortgage Association (“Ginnie Mae”) securities, which are guaranteed by the United States government. (2) Other debt securities presented in this line primarily consist of Japanese negotiable certificates of deposit (“NCDs”), of which the total fair values were ¥106,101 million at March 31, 2018, and ¥6,725 million at March 31, 2019. (3) Other debt securities presented in this line primarily consist of Foreign NCDs and asset-backed securities (“ABS”), of which the total fair values were ¥313,164 million at March 31, 2018, and ¥246,503 million at March 31, 2019. (4) The MHFG Group adopted ASU No.2016-01 available-for-sale (5) All Agency mortgage-backed securities presented in this line are Ginnie Mae securities.
Amortized Cost and Fair Value of Available-for-Sale and Held-to-Maturity Securities by Contractual Maturity	The amortized cost and fair value of available-for-sale held-to-maturity Amortized cost Due in one Due after one Due after five Due after Total (in millions of yen) Available-for-sale Debt securities: Japanese government bonds 7,839,925 2,326,357 1,461,333 260,895 11,888,510 Japanese local government bonds 7,229 118,677 77,336 5,066 208,308 U.S. Treasury bonds and federal agency securities 989,921 18,982 — — 1,008,903 Other foreign government bonds 1,106,386 235,178 — — 1,341,564 Agency mortgage-backed securities — — — 530,540 530,540 Residential mortgage-backed securities — — 4,656 95,248 99,904 Commercial mortgage-backed securities 9,501 175,819 282,518 27,475 495,313 Japanese corporate bonds and other debt securities 137,824 876,876 521,851 206,758 1,743,309 Foreign corporate bonds and other debt securities 443,476 291,299 40,544 2,769 778,088 Total 10,534,262 4,043,188 2,388,238 1,128,751 18,094,439 Held-to-maturity Debt securities: Japanese government bonds 639,984 379,837 100,078 — 1,119,899 Agency mortgage-backed securities — — — 484,205 484,205 Total 639,984 379,837 100,078 484,205 1,604,104 Fair value Due in one Due after one Due after five Due after Total (in millions of yen) Available-for-sale Debt securities: Japanese government bonds 7,840,638 2,329,473 1,465,030 261,630 11,896,771 Japanese local government bonds 7,263 119,115 78,275 5,239 209,892 U.S. Treasury bonds and federal agency securities 990,029 19,287 — — 1,009,316 Other foreign government bonds 1,106,543 235,324 — — 1,341,867 Agency mortgage-backed securities — — — 544,471 544,471 Residential mortgage-backed securities — — 4,656 96,477 101,133 Commercial mortgage-backed securities 9,518 177,237 285,849 27,519 500,123 Japanese corporate bonds and other debt securities 138,670 878,396 524,003 208,365 1,749,434 Foreign corporate bonds and other debt securities 443,626 293,831 40,683 2,769 780,909 Total 10,536,287 4,052,663 2,398,496 1,146,470 18,133,916 Held-to-maturity Debt securities: Japanese government bonds 640,928 395,085 103,793 — 1,139,806 Agency mortgage-backed securities — — — 469,782 469,782 Total 640,928 395,085 103,793 469,782 1,609,588
Other-Than-Temporary Impairment Losses on Available-for-Sale Securities	The following table shows the other-than-temporary impairment losses on available-for-sale held-to-maturity 2017 2018 2019 (in millions of yen) Available-for-sale Debt securities 138 1,015 213 Equity securities (Note) 12,029 3,080 — Total 12,167 4,095 213 Note: Effective April 1, 2018, the available-for-sale
Gross Unrealized Losses and Fair Value of Available-for-Sale and Held-to-Maturity Securities, Aggregated by Length of Time that Individual Securities Have Been in a Continuous Unrealized Loss Position	The following table shows the gross unrealized losses and fair value of available-for-sale held-to-maturity Less than 12 months 12 months or more Total Fair Gross Fair Gross Fair Gross (in millions of yen) 2018 Available-for-sale Debt securities: Japanese government bonds 8,052,820 3,716 2,868,078 5,940 10,920,898 9,656 Japanese local government bonds 28,827 139 58,998 141 87,825 280 U.S. Treasury bonds and federal agency securities 515,005 3,557 — — 515,005 3,557 Other foreign government bonds 419,648 1,030 68,359 72 488,007 1,102 Agency mortgage-backed securities (1) 45,434 1,116 188,326 6,512 233,760 7,628 Residential mortgage-backed securities 11,336 14 16,129 267 27,465 281 Commercial mortgage-backed securities 68,723 242 7,835 81 76,558 323 Japanese corporate bonds and other debt securities 563,831 933 403,069 477 966,900 1,410 Foreign corporate bonds and other debt securities 358,410 888 87,472 1,194 445,882 2,082 Equity securities (marketable) (2) 338,243 11,249 366 42 338,609 11,291 Total 10,402,277 22,884 3,698,632 14,726 14,100,909 37,610 Held-to-maturity Debt securities: Agency mortgage-backed securities (3) 30,589 766 506,875 19,411 537,464 20,177 Total 30,589 766 506,875 19,411 537,464 20,177 2019 Available-for-sale Debt securities: Japanese government bonds 2,296,536 1,441 1,332,688 1,557 3,629,224 2,998 Japanese local government bonds 9,752 32 38,873 55 48,625 87 U.S. Treasury bonds and federal agency securities 506,176 231 — — 506,176 231 Other foreign government bonds 438,771 321 26,782 134 465,553 455 Agency mortgage-backed securities (1) 466 2 37,706 591 38,172 593 Residential mortgage-backed securities — — 16,729 191 16,729 191 Commercial mortgage-backed securities 11,256 44 36,760 60 48,016 104 Japanese corporate bonds and other debt securities 417,825 924 440,937 637 858,762 1,561 Foreign corporate bonds and other debt securities 129,164 142 79,716 84 208,880 226 Equity securities (marketable) (2) — — — — — — Total 3,809,946 3,137 2,010,191 3,309 5,820,137 6,446 Held-to-maturity Debt securities: Agency mortgage-backed securities (3) — — 469,782 14,423 469,782 14,423 Total — — 469,782 14,423 469,782 14,423 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 ¥88,017 million and ¥145,743 million, respectively, at March 31, 2018, and ¥11,107 million and ¥27,065 million, respectively, at March 31, 2019. 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 Ginnie Mae securities, which are guaranteed by the United States government. (2) The MHFG Group adopted ASU No.2016-01 available-for-sale (3) All Agency mortgage-backed securities presented in this line are Ginnie Mae securities.
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 2017 2018 2019 (Note) (in millions of yen) Gross realized gains 353,036 314,948 23,777 Gross realized losses (21,163 ) (41,044 ) (26,299 ) Net realized gains (losses) on sales of available-for-sale 331,873 273,904 (2,522 ) Note: Effective April 1, 2018, the available-for-sale
Summary of Composition of Other Investments	The following table summarizes the composition of Other investments at March 31, 2018 and 2019: 2018 2019 (in millions of yen) Equity method investments 280,666 354,268 Investments held by consolidated investment companies 37,735 35,472 Other equity interests 267,495 — (Note) Total 585,896 389,740 Note: In connection with the adoption of ASU No.2016-01,
Summary of Details of Net Gains and Losses on Equity Securities	The following table shows the details of the net gains and losses on Equity securities for the fiscal year ended March 31, 2019: 2019 (in millions of yen) Net gains and losses recognized during the period on equity securities (155,947 ) Less: Net gains and losses recognized during the period on equity securities sold during the period 34,034 Unrealized gains and losses recognized during the reporting period on equity securities still held at the reporting period (189,981 )
Summary of Equity Securities Without Readily Determinable Fair Values	The following table shows the details of Equity securities without readily determinable fair values, for which the measurement alternative is used, for the fiscal year ended March 31, 2019: 2019 (in millions of yen) Carrying amounts at the end of the period 212,270 Downward adjustments and impairments: During the period 1,413 Cumulative 1,413 Upward adjustments: During the period 2,373 Cumulative 2,373

Loans (Tables)

Loans (Tables)	12 Months Ended
	Mar. 31, 2019
Loans Outstanding by Domicile and Industry of Borrower	The table below presents loans outstanding by domicile and industry of borrower at March 31, 2018 and 2019: 2018 2019 (in millions of yen) Domestic: Manufacturing 8,156,341 9,558,146 Construction and real estate 8,101,668 8,954,823 Services 5,024,018 5,113,386 Wholesale and retail 5,112,673 5,163,267 Transportation and communications 3,564,869 3,622,130 Banks and other financial institutions 4,471,423 4,303,231 Government and public institutions 8,882,125 2,358,904 Other industries (Note) 5,018,387 5,477,452 Individuals: Mortgage loans 9,445,286 8,950,216 Other 883,724 907,589 Total domestic 58,660,514 54,409,144 Foreign: Commercial and industrial 17,195,159 19,086,511 Banks and other financial institutions 7,465,140 9,126,392 Government and public institutions 302,891 296,872 Other 37,636 33,171 Total foreign 25,000,826 28,542,946 Total 83,661,340 82,952,090 Less: Unearned income and deferred loan fees—net 146,696 152,147 Total loans before allowance for loan losses 83,514,644 82,799,943 Note: Other industries of Domestic includes trade receivables and lease receivables of consolidated VIEs.
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, 2018 and 2019: Normal obligors Watch obligors excluding (1) Impaired Total Corporate Retail (2) Other (3) Corporate Retail (2) Other (3) (in millions of yen) 2018 Domestic: Manufacturing 7,705,495 77,947 23,343 197,465 9,775 246 142,070 8,156,341 Construction and real estate 7,317,972 541,778 13,332 172,287 15,466 — 40,833 8,101,668 Services 4,535,793 172,045 141,718 95,223 21,109 55 58,075 5,024,018 Wholesale and retail 4,636,236 177,965 17,305 121,832 27,975 476 130,884 5,112,673 Transportation and communications 3,414,781 76,532 1,774 35,339 8,916 — 27,527 3,564,869 Banks and other financial institutions 4,244,101 1,640 196,431 16,716 194 — 12,341 4,471,423 Government and public institutions 3,010,708 — 5,871,417 — — — — 8,882,125 Other industries (4) 2,716,502 3,536 2,170,442 2,708 259 121,201 3,739 5,018,387 Individuals 222,410 9,822,244 88,044 23,491 81,550 1,109 90,162 10,329,010 Total domestic 37,803,998 10,873,687 8,523,806 665,061 165,244 123,087 505,631 58,660,514 Foreign: Commercial and industrial 14,192,930 209 2,432,189 398,231 — 64,950 106,650 17,195,159 Banks and other financial institutions 6,949,036 — 487,978 28,126 — — — 7,465,140 Government and public institutions 301,072 — — — — — 1,819 302,891 Other 1,906 9,245 23,730 242 6 1,347 1,160 37,636 Total foreign 21,444,944 9,454 2,943,897 426,599 6 66,297 109,629 25,000,826 Total 59,248,942 10,883,141 11,467,703 1,091,660 165,250 189,384 615,260 83,661,340 2019 Domestic: Manufacturing 9,209,834 69,080 19,805 141,202 8,278 1,303 108,644 9,558,146 Construction and real estate 8,186,308 505,142 15,920 186,753 14,490 25 46,185 8,954,823 Services 4,761,724 165,643 3,281 90,578 18,586 1 73,573 5,113,386 Wholesale and retail 4,686,541 161,392 26,881 127,695 25,553 591 134,614 5,163,267 Transportation and communications 3,472,991 71,934 934 37,593 7,472 — 31,206 3,622,130 Banks and other financial institutions 4,262,125 1,534 72 28,881 319 — 10,300 4,303,231 Government and public institutions 2,358,899 5 — — — — — 2,358,904 Other industries (4) 3,131,072 2,450 2,323,197 7,725 421 3,633 8,954 5,477,452 Individuals 233,986 9,384,955 64,974 21,127 70,427 1,168 81,168 9,857,805 Total domestic 40,303,480 10,362,135 2,455,064 641,554 145,546 6,721 494,644 54,409,144 Foreign: Commercial and industrial 16,061,655 182 2,488,800 347,060 — 38,404 150,410 19,086,511 Banks and other financial institutions 8,623,103 — 492,831 10,458 — — — 9,126,392 Government and public institutions 296,870 — — — — — 2 296,872 Other 1,480 9,713 19,690 333 — 879 1,076 33,171 Total foreign 24,983,108 9,895 3,001,321 357,851 — 39,283 151,488 28,542,946 Total 65,286,588 10,372,030 5,456,385 999,405 145,546 46,004 646,132 82,952,090 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 impaired. (2) The obligor category classification is mainly based on past due status. (3) Non-impaired (4) Other industries of Domestic includes trade receivables and lease receivables of consolidated VIEs.
Impaired Loans Information	The table below presents impaired loans information at March 31, 2018 and 2019: Recorded investment (1) Unpaid Related (3) Average Interest (4) Requiring an Not (2) Total (in millions of yen) 2018 Domestic: Manufacturing 135,083 6,987 142,070 146,857 45,750 218,899 1,869 Construction and real estate 31,557 9,276 40,833 48,752 4,411 49,926 516 Services 48,691 9,384 58,075 64,348 13,305 60,198 919 Wholesale and retail 119,463 11,421 130,884 139,556 42,798 139,333 1,842 Transportation and communications 25,019 2,508 27,527 28,480 6,862 25,672 370 Banks and other financial institutions 8,392 3,949 12,341 12,341 3,176 8,648 78 Other industries 3,650 89 3,739 3,869 3,563 4,537 53 Individuals 43,326 46,836 90,162 95,338 4,315 97,404 1,402 Total domestic 415,181 90,450 505,631 539,541 124,180 604,617 7,049 Foreign: Total foreign (5) 63,346 46,283 109,629 125,329 28,333 151,588 1,042 Total 478,527 136,733 615,260 664,870 152,513 756,205 8,091 2019 Domestic: Manufacturing 103,039 5,605 108,644 111,533 39,301 122,764 1,404 Construction and real estate 36,873 9,312 46,185 51,158 4,661 42,224 487 Services 64,021 9,552 73,573 79,736 16,311 67,679 1,058 Wholesale and retail 124,911 9,703 134,614 147,665 38,763 130,860 1,814 Transportation and communications 28,297 2,909 31,206 32,139 13,146 29,864 412 Banks and other financial institutions 6,473 3,827 10,300 10,300 1,327 10,671 109 Other industries 8,867 87 8,954 9,149 5,761 6,042 29 Individuals 37,488 43,680 81,168 88,331 2,630 86,082 1,326 Total domestic 409,969 84,675 494,644 530,011 121,900 496,186 6,639 Foreign: Total foreign (5) 119,079 32,409 151,488 164,984 47,345 113,559 1,518 Total 529,048 117,084 646,132 694,995 169,245 609,745 8,157 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 impaired loans. (2) These impaired loans do not require an allowance for loan losses because the MHFG Group has sufficient collateral to cover probable loan losses. (3) The allowance for loan losses on impaired loans includes the allowance for groups of loans which were collectively evaluated for impairment, in addition to the allowance for those loans that were individually evaluated for impairment. The total carrying amount of the groups of loans which were collectively evaluated for impairment at March 31, 2018 and 2019 was ¥245,809 million and ¥257,099 million, respectively. (4) Amounts represent the amount of interest income on impaired loans recognized on a cash basis and included in Interest income on loans in the consolidated statements of income. (5) The majority of Total foreign consist of Commercial and Industrial loans.
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 fiscal years ended March 31, 2018 and 2019: Loan forgiveness or debt to Interest rate Recorded (1 ) Charge-offs (in millions of yen) 2018 Domestic: Manufacturing — — 110,624 Construction and real estate — — 13,430 Services — — 40,774 Wholesale and retail — — 148,560 Transportation and communications — — 27,294 Banks and other financial institutions — — 8,529 Other industries — — 246 Individuals — — 14,960 Total domestic — — 364,417 Foreign: Total foreign (2) — — 44,010 Total — — 408,427 2019 Domestic: Manufacturing — — 134,544 Construction and real estate — — 39,254 Services — — 87,468 Wholesale and retail — — 167,299 Transportation and communications — — 33,991 Banks and other financial institutions — — 17,286 Other industries — — 120 Individuals — — 42,330 Total domestic — — 522,292 Foreign: Total foreign (2) 984 1,964 44,033 Total 984 1,964 566,325 Notes: (1) Amounts represent the book values of loans immediately after the restructurings. (2) The majority of Total foreign consist of Commercial and Industrial loans.
Payment Defaults Occurred During Periods with Respect to Loans Modified as Troubled Debt Restructurings within Previous Twelve Months	The following table presents payment defaults which occurred during the fiscal years ended March 31, 2018 and 2019 with respect to the loans modified as TDRs within the previous twelve months: Recorded investment 2018 2019 (in millions of yen) Domestic: Manufacturing 4,019 1,173 Construction and real estate 80 121 Services 4,469 1,335 Wholesale and retail 25,710 15,087 Transportation and communications 264 878 Banks and other financial institutions — 66 Other industries 130 1,650 Individuals 1,819 2,152 Total domestic 36,491 22,462 Foreign: Total foreign 4,588 5,418 Total 41,079 27,880
Age Analysis of Past Due Loans	The table below presents an analysis of the age of the recorded investment in loans that are past due at March 31, 2018 and 2019: 30-59 days 60-89 days 90 days or Total past Current Total (in millions of yen) 2018 Domestic: Manufacturing 585 470 8,037 9,092 8,147,249 8,156,341 Construction and real estate 1,641 474 28,633 30,748 8,070,920 8,101,668 Services 1,977 1,142 5,051 8,170 5,015,848 5,024,018 Wholesale and retail 1,704 1,083 6,639 9,426 5,103,247 5,112,673 Transportation and communications 356 639 1,828 2,823 3,562,046 3,564,869 Banks and other financial institutions — 1,301 — 1,301 4,470,122 4,471,423 Government and public institutions — — — — 8,882,125 8,882,125 Other industries 33 12 37 82 5,018,305 5,018,387 Individuals 31,566 12,426 31,444 75,436 10,253,574 10,329,010 Total domestic 37,862 17,547 81,669 137,078 58,523,436 58,660,514 Foreign: Total foreign (Note) 897 450 41,316 42,663 24,958,163 25,000,826 Total 38,759 17,997 122,985 179,741 83,481,599 83,661,340 2019 Domestic: Manufacturing 2,210 513 7,036 9,759 9,548,387 9,558,146 Construction and real estate 1,010 1,054 31,092 33,156 8,921,667 8,954,823 Services 633 196 3,494 4,323 5,109,063 5,113,386 Wholesale and retail 1,614 1,415 7,868 10,897 5,152,370 5,163,267 Transportation and communications 363 256 2,119 2,738 3,619,392 3,622,130 Banks and other financial institutions 3 484 6 493 4,302,738 4,303,231 Government and public institutions — — — — 2,358,904 2,358,904 Other industries 2 — 57 59 5,477,393 5,477,452 Individuals 27,139 11,013 28,965 67,117 9,790,688 9,857,805 Total domestic 32,974 14,931 80,637 128,542 54,280,602 54,409,144 Foreign: Total foreign (Note) 668 211 26,316 27,195 28,515,751 28,542,946 Total 33,642 15,142 106,953 155,737 82,796,353 82,952,090 Note: The majority of Total foreign consist of Commercial and Industrial loans.

Allowance for loan losses (Tabl

Allowance for loan losses (Tables)	12 Months Ended
	Mar. 31, 2019
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 loan losses by portfolio segment for the fiscal years ended March 31, 2017, 2018 and 2019 are shown below: Corporate Retail Other Total (in millions of yen) 2017 Balance at beginning of fiscal year 367,739 44,221 39,287 451,247 Provision (credit) for loan losses 45,059 (10,666 ) 3,275 37,668 Charge-offs (22,901 ) (1,754 ) (6,597 ) (31,252 ) Recoveries 18,320 5,122 2,158 25,600 Net charge-offs (4,581 ) 3,368 (4,439 ) (5,652 ) Others (Note) (890 ) — (2,700 ) (3,590 ) Balance at end of fiscal year 407,327 36,923 35,423 479,673 2018 Balance at beginning of fiscal year 407,327 36,923 35,423 479,673 Provision (credit) for loan losses (123,470 ) (7,427 ) 4,535 (126,362 ) Charge-offs (44,621 ) (2,118 ) (9,123 ) (55,862 ) Recoveries 12,924 814 1,482 15,220 Net charge-offs (31,697 ) (1,304 ) (7,641 ) (40,642 ) Others (Note) (3,088 ) — 321 (2,767 ) Balance at end of fiscal year 249,072 28,192 32,638 309,902 2019 Balance at beginning of fiscal year 249,072 28,192 32,638 309,902 Provision (credit) for loan losses 31,693 (2,658 ) 3,424 32,459 Charge-offs (39,728 ) (2,856 ) (4,940 ) (47,524 ) Recoveries 11,019 552 2,532 14,103 Net charge-offs (28,709 ) (2,304 ) (2,408 ) (33,421 ) Others (Note) 847 — (2,586 ) (1,739 ) Balance at end of fiscal year 252,903 23,230 31,068 307,201 Note: Others includes primarily foreign exchange translation. The table below presents Allowance for loan losses and loans outstanding by portfolio segment disaggregated on the basis of impairment method at March 31, 2018 and 2019: Corporate Retail Other Total (in millions of yen) 2018 Allowance for loan losses 249,072 28,192 32,638 309,902 of which individually evaluated for impairment 129,789 2,602 7,383 139,774 of which collectively evaluated for impairment 119,283 25,590 25,255 170,128 Loans (Note) 60,837,559 11,133,862 11,689,919 83,661,340 of which individually evaluated for impairment 593,053 21,364 61,023 675,440 of which collectively evaluated for impairment 60,244,506 11,112,498 11,628,896 82,985,900 2019 Allowance for loan losses 252,903 23,230 31,068 307,201 of which individually evaluated for impairment 139,472 2,122 8,933 150,527 of which collectively evaluated for impairment 113,431 21,108 22,135 156,674 Loans (Note) 66,804,088 10,596,994 5,551,008 82,952,090 of which individually evaluated for impairment 539,893 20,886 54,319 615,098 of which collectively evaluated for impairment 66,264,195 10,576,108 5,496,689 82,336,992 Note: Amounts represent loan balances before deducting unearned income and deferred loan fees.

Premises and equipment (Tables)

Premises and equipment (Tables)	12 Months Ended
	Mar. 31, 2019
Summary of Premises and Equipment	Premises and equipment at March 31, 2018 and 2019 consist of the following: 2018 2019 (in millions of yen) Land 566,040 563,032 Buildings 811,911 826,781 Equipment and furniture 484,102 472,186 Leasehold improvements 97,066 97,508 Construction in progress 25,849 37,174 Software 1,463,786 1,366,481 Total 3,448,754 3,363,162 Less: Accumulated depreciation and amortization 1,332,570 1,462,210 Premises and equipment—net 2,116,184 1,900,952

Goodwill and intangible assets

Goodwill and intangible assets (Tables)	12 Months Ended
	Mar. 31, 2019
Changes in Goodwill	The changes in Goodwill during the fiscal years ended March 31, 2017, 2018 and 2019 are as follows: 2017 2018 2019 (in millions of yen) Balance at beginning of fiscal year 19,097 95,176 95,184 Goodwill acquired 76,225 (1) — — Foreign exchange translation (146 ) 8 (33 ) Balance at end of fiscal year 95,176 95,184 95,151 Gross amount of goodwill (2) 171,432 170,926 169,489 Accumulated impairment losses 76,256 75,742 74,338 Notes: (1) Goodwill acquired is entirely related to the acquisition of Asset Management One (see Note 3 “Business combination”). (2) Goodwill is recorded at a designated reporting unit level for the purpose of assessing impairment. Goodwill is not allocated to the reportable segments in Note 32 “Business segment information”.
Gross Carrying Amount, Accumulated Amortization and Net Carrying Amount of Intangible Assets	The table below presents the gross carrying amount, accumulated amortization and net carrying amount of intangible assets, at March 31, 2018 and 2019: 2018 2019 Gross Accumulated Net Gross Accumulated Net (in millions of yen) Intangible assets subject to amortization: Customer relationships (Note) 126,979 52,237 74,742 126,882 61,630 65,252 Other 1,847 1,341 506 1,698 1,412 286 Total 128,826 53,578 75,248 128,580 63,042 65,538 Intangible assets not subject to amortization: Total 9,199 — 9,199 8,702 — 8,702 Total 138,025 53,578 84,447 137,282 63,042 74,240 Note: Customer relationships were acquired in connection with the merger of MHSC and Shinko on May 7, 2009 and the integration among asset management companies on October 1, 2016, see Note 3 “Business combination” for further details of the integration among asset management companies. See Note 1 “Basis of presentation and summary of significant accounting policies” for further information.
Estimated Aggregate Amortization Expense in Respect of Intangible Assets	The table below presents the estimated aggregate amortization expense in respect of intangible assets for the next five years: (in millions of yen) Fiscal year ending March 31: 2020 8,969 2021 8,237 2022 7,702 2023 7,184 2024 6,666

Pledged assets and collateral (

Pledged assets and collateral (Tables)	12 Months Ended
	Mar. 31, 2019
Amounts Pledged as Collateral for Borrowings and for Other Purposes	The following amounts, by balance sheet classification, have been pledged as collateral for borrowings and for other purposes at March 31, 2018 and 2019: 2018 2019 (in billions of yen) Interest-bearing deposits in other banks 37 68 Trading account assets 5,611 4,137 Investments 6,500 6,076 Loans 5,229 4,055 Other assets 2,099 1,886 Total 19,476 16,222
Associated Liabilities Collateralized by Pledged Assets	The associated liabilities collateralized by the above assets at March 31, 2018 and 2019 are summarized below: 2018 2019 (in billions of yen) Deposits 256 386 Payables under repurchase agreements 5,518 3,435 Payables under securities lending transactions 1,193 1,675 Other short-term borrowings 441 519 Long-term debt 3,179 1,431 Total 10,587 7,446

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Mar. 31, 2019
Balances of Time Deposits and Certificates of Deposit Issued by Domestic Offices in Amounts of JPY10 Million or More and by Foreign Offices in Amounts of USD100,000 or More	The balances of time deposits and certificates of deposit issued by domestic offices in amounts of ¥10 million (approximately US$90 thousand at the Federal Reserve Bank of New York’s noon buying rate on March 31, 2019) or more and the balances of these deposits issued by foreign offices in amounts of US$100,000 or more at March 31, 2018 and 2019 are as follows: 2018 2019 (in millions of yen) Domestic offices: Time deposits 17,194,707 16,578,642 Certificates of deposit 5,778,430 5,643,303 Total 22,973,137 22,221,945 Foreign offices: Time deposits 13,426,554 17,606,520 Certificates of deposit 5,604,160 7,695,240 Total 19,030,714 25,301,760
Balance and Remaining Maturities of Time Deposits and Certificates of Deposit Issued by Domestic and Foreign Offices	The balance and remaining maturities of time deposits and certificates of deposit issued by domestic and foreign offices at March 31, 2019 are shown in the following table: Time Certificates of Total (in millions of yen) Domestic offices: Due in one year or less 21,240,581 5,492,603 26,733,184 Due after one year through two years 1,709,682 150,700 1,860,382 Due after two years through three years 1,387,191 — 1,387,191 Due after three years through four years 319,829 — 319,829 Due after four years through five years 371,921 — 371,921 Due after five years 245,455 — 245,455 Total 25,274,659 5,643,303 30,917,962 Foreign offices: Due in one year or less 17,525,778 7,468,492 24,994,270 Due after one year through two years 65,423 162,721 228,144 Due after two years through three years 3,902 64,055 67,957 Due after three years through four years 775 — 775 Due after four years through five years 11,369 — 11,369 Due after five years 11,122 — 11,122 Total 17,618,369 7,695,268 25,313,637 Total 42,893,028 13,338,571 56,231,599

Short-term borrowings and lon_2

Short-term borrowings and long-term debt (Tables)	12 Months Ended
	Mar. 31, 2019
Details of Other Short-Term Borrowings	Details of Other short-term borrowings at March 31, 2018 and 2019 are as follows: 2018 2019 (in millions of yen) Short-term notes issued by consolidated VIEs of asset-backed commercial paper programs (1) 27,985 22,339 Commercial paper and short-term notes issued by MHFG’s subsidiaries (1) (2) 1,044,591 1,274,382 Borrowings from the Bank of Japan 432,328 508,627 Other 183,114 189,478 Total 1,688,018 1,994,826 Notes: (1) Short-term notes are issued under the laws of Japan in the form of commercial paper. (2) The amounts of commercial paper and short-term notes issued by MHFG’s subsidiaries were ¥710,391 million and ¥334,200 million, respectively, at March 31, 2018, and ¥941,182 million and ¥333,200 million, respectively, at March 31, 2019.
Long-Term Debt with Original Maturities of More than One Year	Long-term debt with original maturities of more than one year at March 31, 2018 and 2019 is comprised of the following: 2018 2019 (in millions of yen) Obligations under capital leases 36,010 25,020 Loan participation borrowings 89,353 142,838 Senior borrowings and bonds 9,184,075 7,503,032 Subordinated borrowings and bonds 3,645,792 3,858,510 Total 12,955,230 11,529,400
Interest Rates and Maturities of Senior Borrowings and Bonds, and Subordinated Borrowings and Bonds	The following table presents the interest rates and maturities of senior borrowings and bonds, and subordinated borrowings and bonds: Interest rates (1) Maturities (2) 2018 2019 (%) (in millions of yen) Senior borrowings and bonds: fixed rate denominated in Japanese yen 0.00-8.10 Apr. 2019-Dec. 4,146,989 2,057,156 fixed rate denominated in U.S. dollars 0.00-5.39 Apr. 2019-Mar. 2,519,845 2,765,247 fixed rate denominated in other currencies 0.02-12.40 Apr. 2019-May. 2037 233,842 324,162 floating rate denominated in Japanese yen 0.00-25.00 Apr. 2019-Mar. 662,751 656,029 floating rate denominated in U.S. dollars 0.00-16.00 Apr. 2019-Jul. 1,469,248 1,493,617 floating rate denominated in other currencies 0.00-9.00 Apr. 2019-Mar. 151,400 206,821 Total 9,184,075 7,503,032 Subordinated borrowings and bonds: fixed rate denominated in Japanese yen 0.40-4.26 Jun. 2019-Perpetual 3,247,639 3,442,438 fixed rate denominated in U.S. dollars 4.30-4.70 Jul. 2022-Oct. 398,153 416,072 Total 3,645,792 3,858,510 Total 12,829,867 11,361,542 Notes: (1) The interest rates disclosed reflect the range of contractual rates in effect at March 31, 2019. (2) Maturity information disclosed is the range of maturities at March 31, 2019. (3) None of the long-term debt issuances above are convertible to common stock. (4) Certain debt agreements permit the MHFG Group to redeem the related debt, in whole or in part, prior to maturity at the MHFG Group’s option on terms specified in the respective agreements.
Contractual Maturities of Long-Term Debt	The following is a summary of contractual maturities of long-term debt subsequent to March 31, 2019: (in millions of yen) Fiscal year ending March 31: 2020 1,401,583 2021 1,443,458 2022 1,319,030 2023 1,176,818 2024 508,821 2025 and thereafter 5,679,690 Total 11,529,400

Other assets and liabilities (T

Other assets and liabilities (Tables)	12 Months Ended
	Mar. 31, 2019
Details of Other Assets and Liabilities	The following table sets forth the details of other assets and liabilities at March 31, 2018 and 2019: 2018 2019 (in millions of yen) Other assets: Accounts receivable: Receivables from brokers, dealers and customers for securities transactions (1) 1,578,952 1,517,235 Other 368,030 400,676 Collateral pledged: Collateral pledged for derivative transactions 981,390 856,439 Margins provided for futures contracts 142,156 159,747 Other 965,137 857,814 Prepaid pension cost 874,191 850,472 Security deposits 126,001 123,317 Loans held for sale 86,153 24,921 Other 609,624 485,383 Total 5,731,634 5,276,004 Other liabilities: Accounts payable: Payables to brokers, dealers and customers for securities transactions (1) 1,410,785 2,572,315 Other 455,789 442,776 Guaranteed trust principal (2) 761,685 809,450 Collateral accepted: Collateral accepted for derivative transactions 598,524 589,411 Margins accepted for futures contracts 325,038 339,863 Unearned income (3) 130,916 126,594 Other 1,022,858 1,052,297 Total 4,705,595 5,932,706 Notes: (1) Receivables from brokers, dealers and customers for securities transactions included ¥372,395 million and ¥555,938 million of such receivables of consolidated VIEs at March 31, 2018 and 2019, respectively. Payables to brokers, dealers and customers for securities transactions included ¥422,060 million and ¥620,766 million of such payables of consolidated VIEs at March 31, 2018 and 2019, respectively. (2) Guaranteed trust principal is the 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 25 “Variable interest entities and securitizations” for further discussion of the guaranteed principal money trusts. (3) Unearned income is primarily comprised of loan fees received from consumer loan customers when loans are made. This income is being deferred and recognized in earnings over the life of the loan.

Preferred stock (Tables)

Preferred stock (Tables)	12 Months Ended
	Mar. 31, 2019
Common Stock
Schedule of Stock by Class	The following table shows the changes in the number of issued shares of common stock during the fiscal years ended March 31, 2017, 2018 and 2019: 2017 2018 2019 (shares) Balance at beginning of fiscal year 25,030,525,657 25,386,307,945 25,389,644,945 Issuance of new shares of common stock due to conversion of class XI preferred stock 349,677,288 — — Issuance of new shares of common stock due to exercise of stock acquisition rights 6,105,000 3,337,000 2,854,000 Balance at end of fiscal year 25,386,307,945 25,389,644,945 25,392,498,945
Preferred stock
Schedule of Stock by Class	The composition of preferred stock at March 31, 2017, 2018 and 2019 is as follows: March 31, 2017 March 31, 2018 March 31, 2019 Class of stock Authorized Issued Authorized Issued Authorized Issued (number of shares) Class XI preferred stock 914,752,000 — — — — — Class XIV preferred stock 900,000,000 — 900,000,000 — 900,000,000 — Class XV preferred stock 900,000,000 — 900,000,000 — 900,000,000 — Class XVI preferred stock 1,500,000,000 — 1,500,000,000 — 1,500,000,000 —
Summary of Changes in Number of Issued Shares of Common Stock	The following table shows the changes in the number of shares and the aggregate amount of preferred stock during the fiscal year ended March 31, 2017: 2017 (shares) (in millions of yen) Balance at beginning of fiscal year 914,752,000 914,752 Net change ( Note) (914,752,000 ) (914,752 ) Balance at end of fiscal year — — Note: In July 2016, all shares of the class XI preferred stock were converted into common stock and cancelled.

Accumulated other comprehensi_2

Accumulated other comprehensive income (Tables)	12 Months Ended
	Mar. 31, 2019
Changes in Each Component of AOCI	Changes in each component of AOCI for the fiscal years ended March 31, 2017, 2018 and 2019 are as follows: 2017 2018 2019 (in millions of yen) AOCI, balance at beginning of fiscal year, previously reported 1,469,308 1,521,163 1,741,894 Cumulative effect of change in accounting principles 330 — (1,535,142 ) (1) AOCI, balance at beginning of fiscal year, adjusted 1,469,638 1,521,163 206,752 Net unrealized gains (losses) on available-for-sale Balance at beginning of fiscal year, previously reported 1,409,459 1,461,302 1,556,585 Cumulative effect of change in accounting principles (85 ) — (1,525,064 ) (1) Balance at beginning of fiscal year, adjusted 1,409,374 1,461,302 31,521 Unrealized holding gains (losses) during year 273,844 282,141 (11,358 ) Less: reclassification adjustments for losses (gains) included in net income (221,916 ) (186,858 ) 1,856 Change during year 51,928 95,283 (9,502 ) Balance at end of fiscal year 1,461,302 1,556,585 22,019 Foreign currency translation adjustments: Balance at beginning of fiscal year, previously reported 6,310 (5,535 ) (35,076 ) Cumulative effect of change in accounting principles 415 — — Balance at beginning of fiscal year, adjusted 6,725 (5,535 ) (35,076 ) Foreign currency translation adjustments during year (11,920 ) (26,936 ) (22,737 ) Less: reclassification adjustments for losses (gains) included in net income (340 ) (2,605 ) (745 ) Change during year (12,260 ) (29,541 ) (23,482 ) Balance at end of fiscal year (5,535 ) (35,076 ) (58,558 ) Pension liability adjustments: Balance at beginning of fiscal year 53,539 65,396 220,385 Unrealized gains (losses) during year 11,561 157,737 (17,243 ) Less: reclassification adjustments for losses (gains) included in net income 296 (2,748 ) (6,696 ) Change during year 11,857 154,989 (23,939 ) Balance at end of fiscal year 65,396 220,385 196,446 Own credit risk adjustments ( 2 ) Balance at beginning of fiscal year, previously reported — — — Cumulative effect of change in accounting principles — — (10,078 ) ( 1 ) Balance at beginning of fiscal year, adjusted — — (10,078 ) Unrealized gains (losses) during year — — 14,293 Less: reclassification adjustments for losses (gains) included in net income — — (101 ) Change during year — — 14,192 Balance at end of fiscal year — — 4,114 Total other comprehensive income (loss), net of tax attributable to MHFG shareholders 51,525 220,731 (42,731 ) AOCI, balance at end of fiscal year 1,521,163 1,741,894 164,021 Notes: (1) See Note 2 “Recently issued accounting pronouncements” for further details of the cumulative-effect adjustment for AOCI. (2) The MHFG Group adopted ASU No.2016-01
Amounts Reclassified Out of Accumulated Other Comprehensive Income into Net Income	The following table shows the amounts reclassified out of AOCI into net income during the fiscal year ended March 31, 2019: Before tax (1) Tax effect (2) Net of tax before Net of tax attributable to (2) Net of tax attributable shareholders (in millions of yen) Amounts reclassified out of AOCI into net income: Affected line items in the consolidated statements of income: Net unrealized gains (losses) on available-for-sale (2,735 ) 889 (1,846 ) (10 ) (1,856 ) Investment gains (losses)—net Foreign currency translation adjustments 745 — 745 — 745 Investment gains (losses)—net Pension liability adjustments 9,068 (2,370 ) 6,698 (2 ) 6,696 Salaries and employee benefits Own credit risk adjustments 152 (47 ) 105 (4 ) 101 Other noninterest income (expenses) Total 7,230 (1,528 ) 5,702 (16 ) 5,686 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 and Net income, respectively.

Regulatory matters (Tables)

Regulatory matters (Tables)	12 Months Ended
	Mar. 31, 2019
Capital Requirements and Regulatory Adjustments Over Transitional Period	The capital requirements and regulatory adjustments are being phased in over a transitional period as follows (italicized percentages indicate those still in transition periods): March 2018 March 2019 March 2020 March 2021 March 2022 Minimum Common Equity Tier 1 capital 4.5 % 4.5 % 4.5 % 4.5 % 4.5 % Minimum Tier 1 capital 6.0 % 6.0 % 6.0 % 6.0 % 6.0 % Minimum total capital 8.0 % 8.0 % 8.0 % 8.0 % 8.0 % Phase out of recognition of capital instruments that no longer qualify as capital 40.0 % 30.0 % 20.0 % 10.0 % 0.0 % Capital conservation buffer 1.875 % 2.5 % 2.5 % 2.5 % 2.5 % Countercyclical capital buffer (1) 0.01 % 0.05 % 0.05 % 0.05 % 0.05 % Additional loss absorbency requirements for G-SIBs D-SIBs ( 2 ) 0.75 % 1.0 % 1.0 % 1.0 % 1.0 % Minimum Leverage Ratio 3.0 % 3.0 % 3.0 % 3.0 % 3.5 % (3) Notes: (1) Figures assume that the countercyclical capital buffer will continue to be 0.05% after March 2019. (2) Figures assume that the additional loss absorbency requirements applied to the Group as a G-SIB D-SIB (3) This figure includes a leverage ratio buffer required to be met at 50% of the additional loss absorbency requirements applied to the Group as a G-SIB under the finalized Basel III reforms.
Capital Adequacy Ratios and Leverage 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, 2018 and 2019 calculated in accordance with Japanese GAAP and the guidelines established by the Financial Services Agency are set forth in the following table: 2018 2019 Amount Ratio Amount Ratio (in billions of yen, except percentages) Consolidated: MHFG: Common Equity Tier 1 capital: Required ( 1 ) 4,247 7.135 4,661 8.05 Actual 7,437 12.49 7,390 12.76 Tier 1 capital: Required ( 1 ) 5,140 8.635 5,529 9.55 Actual 9,192 15.44 9,232 15.94 Total risk-based capital: Required ( 1 ) 6,331 10.635 6,687 11.55 Actual 10,860 18.24 10,918 18.85 Leverage Ratio: Required / — / 3.00 Actual ( 2 ) / 4.28 / 4.42 MHBK: Common Equity Tier 1 capital: Required 2,400 4.50 2,388 4.50 Actual 6,584 12.34 6,690 12.60 Tier 1 capital: Required 3,200 6.00 3,184 6.00 Actual 8,330 15.61 8,527 16.06 Total risk-based capital: Required 4,267 8.00 4,246 8.00 Actual 9,881 18.52 10,098 19.02 Leverage Ratio: Required / — / 3.00 Actual ( 2 ) / 4.53 / 4.44 MHTB: Common Equity Tier 1 capital: Required 112 4.50 95 4.50 Actual 498 19.99 500 23.67 Tier 1 capital: Required 149 6.00 127 6.00 Actual 499 20.05 501 23.70 Total risk-based capital: Required 199 8.00 169 8.00 Actual 505 20.28 505 23.87 Leverage Ratio: Required / — / 3.00 Actual ( 2 ) / 7.03 / 6.55 Non-consolidated: MHBK: Common Equity Tier 1 capital: Required 2,312 4.50 2,272 4.50 Actual 6,330 12.32 6,363 12.60 Tier 1 capital: Required 3,082 6.00 3,029 6.00 Actual 8,081 15.73 8,199 16.23 Total risk-based capital: Required 4,109 8.00 4,039 8.00 Actual 9,619 18.72 9,757 19.32 Leverage Ratio: Required / — / 3.00 Actual ( 3 ) / — / 4.45 MHTB: Common Equity Tier 1 capital: Required 112 4.50 94 4.50 Actual 504 20.28 494 23.58 Tier 1 capital: Required 149 6.00 126 6.00 Actual 504 20.28 494 23.58 Total risk-based capital: Required 199 8.00 168 8.00 Actual 509 20.50 498 23.75 Leverage Ratio: Required / — / 3.00 Actual ( 3 ) / — / 6.53 Notes: (1) The required ratios disclosed above, at March 31, 2018 and 2019, include the transitional capital conservation buffer of 1.875% and 2.5%, respectively, the countercyclical capital buffer of 0.01% and 0.05%, respectively, and the transitional additional loss absorbency requirements for G-SIBs D-SIBs (2) The actual leverage ratios disclosed above, at March 31, 2018, are based on the Pillar 3 requirements. (3) MHBK and MHTB did not calculate the leverage ratios on non-consolidated

Earnings per common share (Tabl

Earnings per common share (Tables)	12 Months Ended
	Mar. 31, 2019
Computation of Basic and Diluted Earnings Per Common Share	The following table sets forth the computation of basic and diluted earnings per common share for the fiscal years ended March 31, 2017, 2018 and 2019: 2017 2018 2019 (in millions of yen) Net income: Net income attributable to MHFG common shareholders 362,440 577,608 84,471 Effect of dilutive securities — — — Net income attributable to common shareholders after assumed conversions 362,440 577,608 84,471 2017 2018 2019 (thousands of shares) Shares: Weighted average common shares outstanding 25,285,899 25,366,345 25,362,376 Effect of dilutive securities: Convertible preferred stock (Note) 82,993 — — Stock options 11,410 7,586 4,522 Weighted average common shares after assumed conversions 25,380,302 25,373,931 25,366,898 2017 2018 2019 (in yen) Amounts per common share: Basic net income per common share 14.33 22.77 3.33 Diluted net income per common share 14.28 22.76 3.33 Note: The number of common shares after assumed conversion of the convertible preferred stock is based on the applicable conversion prices.

Income taxes (Tables)

Income taxes (Tables)	12 Months Ended
	Mar. 31, 2019
Components of Income Tax Expense	The following table presents the components of Income tax expense for the fiscal years ended March 31, 2017, 2018 and 2019: 2017 2018 2019 (in millions of yen) Current: Domestic 130,164 130,573 116,695 Foreign 68,512 47,020 49,871 Total current tax expense 198,676 177,593 166,566 Deferred: Domestic (99,831 ) 58,078 (162,475 ) Foreign (7,601 ) 1,933 5,244 Total deferred tax expense (benefit) (107,432 ) 60,011 (157,231 ) Total income tax expense 91,244 237,604 9,335
Detailed Amounts of Tax Effects of Items Recorded Directly in Equity	The preceding table does not reflect the tax effects of items recorded directly in Equity for the fiscal years ended March 31, 2017, 2018 and 2019. The detailed amounts recorded directly in Equity are as follows: 2017 2018 2019 (in millions of yen) Net unrealized gains (losses) on available-for-sale Unrealized gains (losses) 112,467 123,186 (3,940 ) Less: reclassification adjustments (97,729 ) (82,828 ) 889 Total 14,738 40,358 (3,051 ) Pension liability adjustments: Unrealized gains (losses) 4,785 66,331 (6,558 ) Less: reclassification adjustments 178 190 (2,370 ) Total 4,963 66,521 (8,928 ) Own credit risk adjustments (Note) Unrealized gains (losses) — — 3,033 Less: reclassification adjustments — — (47 ) Total — — 2,986 Total tax effect before allocation to noncontrolling interests 19,701 106,879 (8,993 ) Note: The MHFG Group adopted ASU No.2016-01
Reconciliation of Income Tax Expense at Effective Statutory Tax Rate to Actual Income Tax Expense	The following table shows a reconciliation of Income tax expense at the effective statutory tax rate to the actual income tax expense for the fiscal years ended March 31, 2017, 2018 and 2019: 2017 2018 2019 (in millions of yen, except tax rates) Income before income tax expense 480,375 839,298 85,060 Effective statutory tax rate 30.86 % 30.86 % 30.62 % Income tax calculated at the statutory tax rate 148,244 259,007 26,045 Income not subject to tax (7,521 ) (9,312 ) (8,861 ) Expenses not deductible for tax purposes 1,483 1,421 1,389 Tax rate differentials of subsidiaries (2,165 ) (2,696 ) (3,522 ) Change in valuation allowance 112,781 (1) (9,102 ) (2,444 ) Change in undistributed earnings of subsidiaries 5,217 (1,972 ) (21,347 ) (3) Change in net operating loss carryforwards resulting from intercompany capital transactions 647 — — Effect of enacted change in tax rates — 6,863 (2) (11 ) Reversal of outside basis differences (159,119 ) (1) — — Change in unrecognized tax benefits — — 9,420 Other (8,323 ) (6,605 ) 8,666 Income tax expense 91,244 237,604 9,335 Notes: (1) These amounts for the fiscal year ended March 31, 2017 represent mainly the reversal of an outside basis difference related to certain foreign subsidiaries due to their organizational restructuring and the related increase in the valuation allowance. (2) On December 22, 2017, the President of the United States signed into law the Tax Cuts and Jobs Act, which includes a reduction in the U.S. federal corporate income tax rate from 35% to 21%. The decrease in the Group’s balance of net deferred tax assets, reflecting such tax rate reductions, was recognized as an increase to Income tax expense in the fiscal year ended March 31, 2018. The MHFG Group has completed its analysis and accounting under Staff Accounting Bulletin No. 118 for the effects of the Act. (3) In the fiscal year ended March 31, 2019, the MHFG Group derecognized majority of deferred tax liabilities for undistributed earnings of foreign subsidiaries because the Group has intent and ability to reinvest those earnings indefinitely in certain foreign subsidiaries.
Components of Net Deferred Tax Assets (Liabilities)	The components of net deferred tax assets (liabilities) at March 31, 2018 and 2019 are as follows: 2018 2019 (in millions of yen) Deferred tax assets: Allowance for loan losses 126,977 122,585 Premises and equipment 4,896 73,944 Derivative financial instruments 53,336 48,487 Investments 453,880 — Trading securities 1,988 — Net operating loss carryforwards (Note) 178,256 167,755 Other 204,005 216,568 1,023,338 629,339 Valuation allowance (Note) (163,358 ) (158,581 ) Deferred tax assets, net of valuation allowance 859,980 470,758 Deferred tax liabilities: Prepaid pension cost and accrued pension liabilities 255,239 247,694 Investments — 198,495 Available-for-sale 764,497 12,426 Trading securities — 9,158 Other 89,359 61,330 Deferred tax liabilities 1,109,095 529,103 Net deferred tax assets (liabilities) (249,115 ) (58,345 ) Note: The amount includes ¥110,729 million and ¥107,246 million related to MHSC’s net operating loss carryforwards resulting mainly from the organizational restructuring of certain foreign subsidiaries as of March 31, 2018 and 2019, respectively. The tax effect of the net operating loss carryforwards is substantially offset by ¥86,189 million and ¥88,294 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income.
Breakdown of Net Operating Loss Carryforwards by Tax Jurisdiction	The following table and accompanying footnotes provide a breakdown of deferred tax assets and the valuation allowance recognized in respect of net operating loss carryforwards by tax jurisdiction and by year of expiration as of March 31, 2018 and 2019: Deferred tax assets Valuation allowance Deferred tax assets, net of valuation allowance (in billions of yen) 2018 Japan (1) 117 (88 ) 29 The United States 10 (1 ) 9 The United Kingdom (2) 48 (48 ) — Others 3 (2 ) 1 Total 178 (139 ) 39 2019 Japan (3) 111 (92 ) 19 The United States 8 — 8 The United Kingdom (2) 46 (46 ) — Others 3 (2 ) 1 Total 168 (140 ) 28 Notes: (1) ¥111 billion of the Japan deferred tax assets of ¥117 billion is related to MHSC, which is substantially offset by a valuation allowance, and will expire during the fiscal year ending March 31, 2026. (2) The United Kingdom net operating loss carryforwards may be carried forward indefinitely for tax purposes. (3) ¥107 billion of the Japan deferred tax assets of ¥111 billion is related to MHSC, which is substantially offset by a valuation allowance, and will expire during the fiscal year ending March 31, 2026.
Roll-forward of Valuation Allowance	The following table presents a roll-forward of the valuation allowance for the fiscal years ended March 31, 2017, 2018 and 2019: 2017 2018 2019 (in millions of yen) Balance at beginning of fiscal year 339,922 438,344 163,358 Changes that directly affected Income tax expense 112,781 (9,102 ) (2,444 ) Changes that did not affect Income tax expense: Expiration of net operating loss carryforwards — (264,234 ) — Others (14,359 ) (1,650 ) (2,333 ) Total (14,359 ) (265,884 ) (2,333 ) Balance at end of fiscal year 438,344 163,358 158,581
Net Operating Losses Carryforwards by Expiration Date	These carryforwards are scheduled to expire as follows: Net operating loss (in billions of yen) Fiscal year ending March 31: 2020 — 2021 — 2022 — 2023 12 2024 3 2025 and thereafter (Note) 668 Total 683 Note: Including the net operating loss carryforwards which may be carried forward indefinitely in the United Kingdom.
Roll-forward of Unrecognized Tax Benefits	The following table is a roll-forward of unrecognized tax benefits for the fiscal years ended March 31, 2017, 2018 and 2019: 2017 2018 2019 (in millions of yen) Total unrecognized tax benefits at beginning of fiscal year 1,300 1,867 2,345 Gross amount of increases related to positions taken during prior years 167 224 9,550 Gross amount of increases related to positions taken during the current year 409 351 330 Amount of decreases related to settlements — — — Foreign exchange translation (9 ) (97 ) 98 Total unrecognized tax benefits at end of fiscal year 1,867 2,345 12,323

Pension and other employee be_2

Pension and other employee benefit plans (Tables)	12 Months Ended
	Mar. 31, 2019
Components of Net Periodic Benefit Cost of Severance Indemnities and Pension Plans	The following table presents the components of net periodic cost of the severance indemnities and pension plans for the fiscal years ended March 31, 2017, 2018 and 2019: 2017 2018 2019 (in millions of yen) Service cost-benefits earned during the fiscal year 44,367 43,649 43,698 Interest costs on projected benefit obligations 5,724 7,471 6,933 Expected return on plan assets (35,969 ) (34,916 ) (38,518 ) Amortization of prior service cost (benefits) (195 ) 214 152 Amortization of net actuarial loss (gain) 780 411 (7,886 ) Special termination benefits 3,857 3,960 2,929 Net periodic benefit cost 18,564 20,789 7,308
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss) Before-Tax	Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss) before-tax 2018 2019 (in millions of yen) Net actuarial gain (loss) 216,777 (21,300 ) Amortization of net actuarial loss (gain) 411 (7,886 ) Prior service benefits (cost) (348 ) (109 ) Amortization of prior service cost (benefits) 214 152 Total recognized in other comprehensive income (loss) before-tax 217,054 (29,143 )
Weighted-Average Assumptions Used to Determine Benefit Obligations and Net Periodic Benefit Cost	Weighted-average assumptions used to determine benefit obligations and net periodic benefit cost are as follows: 2017 2018 2019 Weighted-average assumptions used to determine benefit obligations at fiscal year end: Discount rates 0.47 % 0.43 % 0.34 % Rates of increase in future compensation levels 1.80-4.80 % 1.80-4.80 % 1.80-4.80 % Weighted-average assumptions used to determine net periodic benefit cost during the year: Discount rates 0.37 % 0.47 % 0.43 % Rates of increase in future compensation levels 1.80-4.80 % 1.80-4.80 % 1.80-4.80 % Expected rates of return on plan assets 1.73 % 1.58 % 1.60 %
Combined Funded Status and Amounts Recognized in Accompanying Consolidated Balance Sheets	The following table sets forth the combined funded status and amounts recognized in the accompanying consolidated balance sheets at March 31, 2018 and 2019 for the plans of MHFG and its subsidiaries: 2018 2019 (in millions of yen) Change in benefit obligations: Benefit obligations at beginning of fiscal year 1,545,893 1,559,356 Service cost 43,649 43,698 Interest cost 7,471 6,933 Plan participants’ contributions 1,233 1,229 Amendments 348 109 Actuarial loss (gain) 30,633 49,085 Foreign exchange translation (32 ) (817 ) Benefits paid (53,167 ) (52,618 ) Lump-sum (16,672 ) (16,157 ) Benefit obligations at end of fiscal year 1,559,356 1,590,818 Change in plan assets: Fair value of plan assets at beginning of fiscal year 2,200,812 2,405,730 Actual return (negative return) on plan assets 280,251 66,652 Foreign exchange translation (113 ) (390 ) Partial withdrawal of assets from employee retirement benefits trusts (Note) (66,565 ) (27,534 ) Employer contributions 43,279 20,487 Plan participants’ contributions 1,233 1,229 Benefits paid (53,167 ) (52,618 ) Fair value of plan assets at end of fiscal year 2,405,730 2,413,556 Funded status 846,374 822,738 Amounts recognized in the consolidated balance sheets consist of: Prepaid pension cost 874,191 850,472 Accrued pension liability (27,817 ) (27,734 ) Net amount recognized 846,374 822,738 Amounts recognized in Accumulated other comprehensive income (loss) before-tax Prior service benefits (cost) (1,352 ) (1,309 ) Net actuarial gain (loss) 291,230 262,044 Net amount recognized 289,878 260,735 Note: During the fiscal year ended March 31, 2018 and 2019, a subsidiary of MHFG partially withdrew assets from employee retirement benefit trusts, which were established for the payment of employees’ severance pay and retirement pensions. Overall, the trusts remain in overfunded status as of March 31, 2018 and 2019. No gains or losses have been recognized as a result of this transaction.
Plans with Projected Benefit Obligations in Excess of Plan Assets and Plans with Accumulated Benefit Obligations in Excess of Plan Assets	The following table shows the projected benefit obligations and the fair value of plan assets for the plans of MHFG and its subsidiaries with projected benefit obligations in excess of plan assets, and the accumulated benefit obligations and the fair value of plan assets for the plans with accumulated benefit obligations in excess of plan assets at March 31, 2018 and 2019: 2018 2019 (in millions of yen) Plans with projected benefit obligations in excess of plan assets: Projected benefit obligations 59,319 61,579 Fair value of plan assets 31,503 33,845 Plans with accumulated benefit obligations in excess of plan assets: Accumulated benefit obligations 59,319 61,579 Fair value of plan assets 31,503 33,845 Note: The plans with projected benefit obligations in excess of plan assets include those with accumulated benefit obligations in excess of plan assets.
Target Allocation for Plan Assets Excluding those of Employee Retirement Benefit Trusts	MHFG and certain subsidiaries’ target allocation for the plan assets, excluding those of the employee retirement benefit trusts, at March 31, 2019 is as follows: Asset category Asset ratio Japanese equity securities 5.00 % Japanese debt securities 34.00 % Foreign equity securities 25.00 % Foreign debt securities 23.00 % General account of life insurance companies 11.00 % Other 2.00 % Total 100.00 % Note: General account of life insurance companies is a contract with life insurance companies which guarantees payments of principal and predetermined interest payments.
Fair Value of Plan Assets by Asset Category	The following table presents the fair value of plan assets of MHFG and its subsidiaries at March 31, 2018 and 2019, by asset class. For the detailed information on fair value measurements, including descriptions of Level 1, 2 and 3 of the fair value hierarchy and the valuation methodologies, see Note 28 “Fair value”. 2018 2019 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (in billions of yen) Japanese equity securities: Common stocks (1) 1,330 — — 1,330 1,317 — — 1,317 Pooled funds (2) 10 9 — 19 11 4 — 15 Japanese debt securities: Government bonds 184 — — 184 190 — — 190 Pooled funds (2) — 4 — 4 — 10 — 10 Other — 25 — 25 — 24 — 24 Foreign equity securities: Common stocks 108 — — 108 120 — — 120 Pooled funds (2) — 5 — 5 — 5 — 5 Foreign debt securities: Government bonds 175 6 — 181 178 6 — 184 Pooled funds (2) — 9 — 9 — 10 — 10 Other — 16 — 16 — 18 — 18 General account of life insurance companies (3) — 110 — 110 — 111 — 111 Other 92 (4) — — 92 79 (4) 4 — 83 Plan assets measured at net asset (5) 323 327 Total assets at fair value 1,899 184 — 2,406 1,895 192 — 2,414 Notes: (1) This class represents equity securities held in the employee retirement benefit trusts of ¥1,330 billion and ¥1,317 billion carried at fair value at March 31, 2018 and 2019, respectively, which are well-diversified across industries. (2) These classes primarily include pension investment fund trusts. Investments in these classes are generally measured at fair value and can be redeemed within a short-term period upon request. (3) Investments in this class are measured at conversion value, which is equivalent to fair value. (4) Amounts primarily include cash and short-term assets carried at fair value. (5) In accordance with ASC 820, certain plan assets that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy.
Forecasted Benefit Payments Including Effect of Expected Future Service	The following table presents forecasted benefit payments including the effect of expected future service for the fiscal years indicated: (in millions of yen) Fiscal year ending March 31: 2020 68,890 2021 70,015 2022 70,637 2023 71,370 2024 72,606 2025-2029 351,719

Stock-based compensation (Table

Stock-based compensation (Tables)	12 Months Ended
	Mar. 31, 2019
Summary of Stock-Based Compensation Plan	The following is a roll-forward of MHFG Stock Plan for the fiscal year ended March 31, 2019: Number of Weighted-average Weighted-average Aggregate (in yen) (in years) (in millions of yen) Outstanding at beginning of fiscal year 7,216,000 1 Exercised during fiscal year 2,971,000 1 Outstanding at end of fiscal year 4,245,000 1 14.81 723 Exercisable at end of fiscal year — — — —
Activities Related to Stock Compensation Program	The following table presents activities related to the stock compensation programs for the fiscal years ended March 31, 2018 and 2019: Stock Compensation I Stock Compensation II 2018 Number of Weighted-average grant-date fair Number of Weighted-average grant-date fair (per share in yen) (per share in yen) Nonvested at the beginning of the year — — 9,000,000 158.68 Granted during fiscal year — — 8,130,000 196.94 Vested during fiscal year — — 3,810,594 158.68 Forfeited during fiscal year — — — — Nonvested at the end of the year — — 13,319,406 182.04 Stock Compensation I Stock Compensation II 2019 Number of Weighted-average grant-date fair Number of Weighted-average grant-date fair (per share in yen) (per share in yen) Nonvested at the beginning of the year — — 13,319,406 182.04 Granted during fiscal year 3,770,065 189.24 6,906,635 189.24 Vested during fiscal year 3,770,065 189.24 5,068,949 187.48 Forfeited during fiscal year — — — — Nonvested at the end of the year — — 15,157,092 183.50 Note: Stock Compensation I was introduced in the fiscal year ended March 31, 2019.
Total Fair Value of Stock Compensation that Vested and Common Stock Acquired	The following table presents the total fair value of the stock compensation that vested and the total amount of the common stock acquired from the stock market by the trustee for the fiscal years ended March 31, 2018 and 2019: 2018 2019 Stock Stock Stock Stock (in millions of yen) Fair value of vested shares — 782 713 930 Common stock shares acquired — 1,601 713 1,307
Schedule Of Stock-Based Compensation Expense	The following table presents the compensation cost recognized in the stock compensation programs for the fiscal years ended March 31, 2017, 2018 and 2019: 2017 2018 2019 (in millions of yen) Stock Compensation I: — — 713 Stock Compensation II: 354 868 1,287

Derivative financial instrume_2

Derivative financial instruments (Tables)	12 Months Ended
	Mar. 31, 2019
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, 2018 and 2019. 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) 2018 Notional amount (1) Designated Not designated Designated Not designated (in billions of yen) Interest rate contracts 1,004,169 — 7,176 — 7,143 Foreign exchange contracts 155,832 2 2,695 — 2,382 Equity-related contracts 6,189 — 197 9 142 Credit-related contracts 2,708 — 18 — 21 Other contracts 335 — 23 — 19 Total 1,169,233 2 10,109 9 9,707 Fair value Derivative receivables (2) Derivative payables (2) 2019 Notional amount (1) Designated Not designated Designated Not designated (in billions of yen) Interest rate contracts 1,052,267 — 5,786 — 5,610 Foreign exchange contracts 166,383 — 1,959 — 1,758 Equity-related contracts 5,181 — 125 — 142 Credit-related contracts 2,939 — 18 — 17 Other contracts 438 — 16 — 14 Total 1,227,208 — 7,904 — 7,541 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, 2018 and 2019: 2018 2019 Notional amount Fair value Notional amount Fair value (in billions of yen) Credit protection written: Investment grade 1,105 15 1,266 12 Non-investment 197 4 199 3 Total 1,302 19 1,465 15 Credit protection purchased 1,541 (22 ) 1,628 (14 ) 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, 2018 and 2019: Maximum payout/Notional amount 2018 2019 (in billions of yen) One year or less 329 326 After one year through five years 831 1,057 After five years 142 82 Total 1,302 1,465 Note: The maximum potential amount of future payments is the aggregate notional amount of the credit derivatives where the Group wrote the credit protection, and it has not been reduced by the effect of any amounts that the Group may possibly collect on the underlying assets and the related cash flows, nor netted against that of credit protection purchased.
Quantitative Information about Derivative Instruments with Credit-risk-related Contingent Features	The following table shows the quantitative information about derivative instruments with credit-risk-related contingent features at March 31, 2018 and 2019: 2018 2019 (in billions of yen) Aggregate fair value of derivative instruments with credit-risk-related contingent features in net liability positions 572 511 Collateral provided to counterparties in the normal course of business 593 489 Amount required to be posted as collateral or settled immediately if credit-risk-related contingent features were triggered (Note) — 22 Note: There was no amount that the Group would be required to post as collateral or settle immediately on March 31, 2018.
Not Designated as Hedging Instrument
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance	The following table summarizes gains and losses on derivatives not designated or qualifying as hedges during the fiscal years ended March 31, 2017, 2018 and 2019: Gains (losses) recorded in income 2017 2018 2019 (in millions of yen) Interest rate contracts (209,361 ) (63,260 ) 127,242 Foreign exchange contracts 37,129 61,046 6,748 Equity-related contracts (1) 5,131 (94,607 ) 37,875 Credit-related contracts (2) (6,694 ) (2,830 ) (467 ) Other contracts 742 6,330 (1,455 ) Total (173,053 ) (93,321 ) 169,943 Notes: (1) The net gain (loss) excluded from the assessment of the effectiveness of fair value hedges is not included in the above table. (2) Amounts include the net loss of ¥7,594 million, ¥754 million and ¥736 million on the credit derivatives economically managing the credit risk of loans during the fiscal years ended March 31, 2017, 2018 and 2019, respectively.
Fair Value Hedging | Designated as Hedging Instrument
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance	The following table summarizes gains and losses information related to fair value hedges for the fiscal years ended March 31, 2017, 2018: Gains (losses) recorded in income 2017 Derivatives Hedged Hedge Net gain (loss) excluded (in millions of yen) Equity-related contracts (14,747 ) 11,393 — (3,354 ) Total (14,747 ) 11,393 — (3,354 ) Gains (losses) recorded in income 2018 Derivatives Hedged Hedge Net gain (loss) excluded (in millions of yen) Equity-related contracts (23,832 ) 19,631 — (4,201 ) Total (23,832 ) 19,631 — (4,201 )
Net Investment Hedging | Designated as Hedging Instrument
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance	The following table summarizes gains and losses information related to net investment hedges for the fiscal years ended March 31, 2017, 2018 and 2019: Gains (losses) recorded in income and other comprehensive income (“OCI”) 2017 2018 2019 Effective portion Ineffective portion Effective portion Ineffective portion Effective portion Ineffective portion (in millions of yen) Financial instruments hedging foreign exchange risk 16,767 47 (30 ) 90 7,405 107 Total 16,767 47 (30 ) 90 7,405 107 Note: Related to the effective portion of net investment hedges, gains of ¥41 million and ¥186 million were reclassified from Accumulated other comprehensive income to earnings for the fiscal years ended March 31, 2017 and 2019, respectively. No amount related to the effective portion of net investment hedges was reclassified from Accumulated other comprehensive income to earnings for the fiscal year ended March 31, 2018.

Commitments and contingencies (

Commitments and contingencies (Tables)	12 Months Ended
	Mar. 31, 2019
Summary of Maximum Potential Amount of Future Payments under Guarantees	The MHFG Group, when necessary, requires collateral such as cash, investment securities and real estate or third-party guarantees depending on the amount of credit risk involved, and employs means such as sub-participation 2018 Maximum Amount by expiration period One year or less After one year After five years (in billions of yen) Performance guarantees 2,165 1,084 908 173 Guarantees on loans 241 123 28 90 Guarantees on securities 164 32 132 — Other guarantees 2,210 1,555 614 41 Guarantees for the repayment of trust principal 709 639 49 21 Liabilities of trust accounts 13,861 13,546 149 166 Derivative financial instruments 11,654 4,911 4,996 1,747 2019 Maximum Amount by expiration period One year or less After one year After five years (in billions of yen) Performance guarantees 2,307 1,265 878 164 Guarantees on loans 289 164 46 79 Guarantees on securities 145 91 54 — Other guarantees 2,324 1,447 834 43 Guarantees for the repayment of trust principal 65 — 47 18 Liabilities of trust accounts 362 61 148 153 Derivative financial instruments 14,170 5,807 6,434 1,929
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, 2018 and 2019: 2018 2019 (in billions of yen) Commitments to extend credit (Note) 78,448 76,857 Commercial letters of credit 690 778 Total 79,138 77,635 Note: Commitments to extend credit include commitments to invest in securities.
Future Minimum Lease Payments for Capitalized Leases and Rental Payments for Operating Leases	clauses of rentals. The table below shows future minimum lease payments for capitalized leases and future minimum rental payments for operating leases at March 31, 2019: Capitalized leases Operating leases (in millions of yen) Fiscal year ending March 31: 2020 9,942 51,329 2021 7,347 41,227 2022 4,454 34,707 2023 2,661 24,633 2024 915 23,425 2025 and thereafter 222 297,183 Total minimum lease/rental payments 25,541 472,504 Amount representing interest 25,020 Present value of minimum lease payments 521
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, 2018 and 2019: 2018 2019 (in billions of yen) Investment grade 3,930 4,124 Non-investment 850 941 Total 4,780 5,065 Note: Investment grade in the internal rating scale generally corresponds to BBB- or above in the external rating scale.

Variable interest entities an_2

Variable interest entities and securitizations (Tables)	12 Months Ended
	Mar. 31, 2019
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, as of March 31, 2018 and 2019: Consolidated VIEs Significant 2018 Consolidated assets Total assets Maximum (in billions of yen) Asset-backed commercial paper/loan programs 2,185 — — Asset-backed securitizations 627 78 5 Investments in securitization products 374 — — Investment funds 2,661 1,891 533 Trust arrangements and other 21 — — Total 5,868 1,969 538 Consolidated VIEs Significant 2019 Consolidated assets Total assets Maximum (in billions of yen) Asset-backed commercial paper/loan programs 2,249 — — Asset-backed securitizations 571 70 8 Investments in securitization products 372 — — Investment funds 2,836 1,280 410 Trust arrangements and other 20 — — Total 6,048 1,350 418
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, 2018 and 2019: Assets on balance sheets related to unconsolidated VIEs: 2018 2019 (in billions of yen) Trading account assets 89 104 Investments 210 168 Loans 163 71 Total 462 343 Liabilities on balance sheets and maximum exposure to loss related to unconsolidated VIEs: 2018 2019 (in billions of yen) Payables under securities lending transactions 38 47 Trading account liabilities 1 1 Total 39 48 Maximum exposure to loss (Note) 538 418 Note: This represents the maximum amount the Group could possibly be required to record in its consolidated statements of income associated with on-balance-sheet off-balance-sheet

Noninterest income (Tables)

Noninterest income (Tables)	12 Months Ended
	Mar. 31, 2019
Summary of Noninterest Income	Details of Noninterest income for the fiscal years ended March 31, 2017, 2018 and 2019 are as follows: 2017 2018 2019 (in millions of yen) Fee and commission income: Securities-related business (1) 165,857 180,122 145,270 Deposits and lending business (2) 164,572 156,426 152,283 Remittance business (1) 108,368 110,054 110,382 Asset management business (1) 79,426 100,765 97,852 Trust related business (1) 108,931 121,808 124,843 Agency business (1) 36,003 37,397 36,466 Guarantee related business (3) 26,292 28,258 28,582 Fees for other customer services (1) 136,514 130,881 157,612 Total Fee and commission income 825,963 865,711 853,290 Foreign exchange gains (losses)—net (3) 69,453 91,793 93,577 Trading account gains (losses)—net (2) (42,481 ) 236,982 328,841 Investment gains (losses)—net: Debt securities (3) 59,517 7,757 (3,842 ) Equity securities (3) 273,753 289,400 (155,947 ) Equity in earnings (losses) of equity method investees—net (3) 26,785 24,342 29,172 Gains on disposal of premises and equipment (3) 5,638 8,225 5,145 Other noninterest income (2) 149,404 80,453 72,135 Total 1,368,032 1,604,663 1,222,371 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.

Trading account gains and los_2

Trading account gains and losses (Tables)	12 Months Ended
	Mar. 31, 2019
Net Trading Gains and Losses	Net trading gains (losses) for the fiscal years ended March 31, 2017, 2018 and 2019 are comprised of the following: 2017 2018 2019 (in millions of yen) Trading account gains (losses)—net: Trading securities 126,332 333,749 158,162 Derivative contracts: Interest rate contracts (209,361 ) (63,260 ) 127,242 Foreign exchange contracts (1) 37,129 61,046 6,748 Equity-related contracts (2) 1,777 (98,807 ) 37,875 Credit-related contracts ( 3 ) 900 (2,076 ) 269 Other contracts 742 6,330 (1,455 ) Total (42,481 ) 236,982 328,841 Foreign exchange gains (losses)—net ( 4 ) 69,453 91,793 93,577 Net trading gains (losses) 26,972 328,775 422,418 Notes: (1) Amounts include gains and losses on currency swaps. (2) The net gain (loss) excluded from the assessment of the effectiveness of fair value hedges is included in the above table. (3) Amounts do not include the net loss of ¥7,594 million, ¥754 million and ¥736 million on the credit derivatives economically managing the credit risk of loans during the fiscal years ended March 31, 2017, 2018 and 2019, respectively. The net loss is recorded in Other noninterest expenses. (4) Amounts include realized and unrealized gains and losses on both derivative instruments and nonderivative instruments. Amounts on derivative instruments include gains and losses on forward foreign exchange contracts and currency options. Amounts on nonderivative instruments include translation gains and losses related to foreign currency-denominated debt securities reported as Trading securities.

Fair value (Tables)

Fair value (Tables)	12 Months Ended
	Mar. 31, 2019
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, 2018 and 2019, including those for which the MHFG Group has elected the fair value option, are summarized below: 2018 Level 1 Level 2 Level 3 Assets/ (in billions of yen) Assets: Trading securities (1) Japanese government bonds 1,375 43 — 1,418 Japanese local government bonds — 107 — 107 U.S. Treasury bonds and federal agency securities 2,442 209 — 2,651 Other foreign government bonds 1,682 480 — 2,162 Agency mortgage-backed securities — 1,799 — 1,799 Residential mortgage-backed securities — — 12 12 Certificates of deposit and commercial paper — 643 — 643 Corporate bonds and other 25 1,992 1,013 3,030 Equity securities 1,642 — 23 1,665 Trading securities measured at net asset value (2) 705 Derivative financial instruments: Interest rate contracts 39 7,089 48 7,176 Foreign exchange contracts 17 2,667 13 2,697 Equity-related contracts 82 110 5 197 Credit-related contracts — 16 2 18 Other contracts 6 8 9 23 Available-for-sale Japanese government bonds 12,435 897 — 13,332 Japanese local government bonds — 239 — 239 U.S. Treasury bonds and federal agency securities 686 — — 686 Other foreign government bonds 355 703 — 1,058 Agency mortgage-backed securities — 889 — 889 Residential mortgage-backed securities — 65 54 119 Commercial mortgage-backed securities — — 441 441 Japanese corporate bonds and other debt securities — 1,827 163 1,990 Foreign corporate bonds and other debt securities — 799 80 879 Equity securities (marketable) (3) 3,912 121 — 4,033 Other investments — — 38 38 Total assets measured at fair value on a recurring basis 24,698 20,703 1,901 48,007 Liabilities: Trading securities sold, not yet purchased 2,777 618 4 3,399 Derivative financial instruments: Interest rate contracts 42 7,074 27 7,143 Foreign exchange contracts 11 2,370 1 2,382 Equity-related contracts 81 69 1 151 Credit-related contracts — 20 1 21 Other contracts 4 6 9 19 Long-term debt (4) — 1,395 561 1,956 Total liabilities measured at fair value on a recurring basis 2,915 11,552 604 15,071 2019 Level 1 Level 2 Level 3 Assets/ (in billions of yen) Assets: Trading securities (1) Japanese government bonds 1,829 33 — 1,862 Japanese local government bonds — 134 — 134 U.S. Treasury bonds and federal agency securities 1,069 138 — 1,207 Other foreign government bonds 2,417 553 — 2,970 Agency mortgage-backed securities — 1,041 — 1,041 Residential mortgage-backed securities — — 11 11 Certificates of deposit and commercial paper — 1,047 — 1,047 Corporate bonds and other 36 1,806 1,044 2,886 Equity securities 1,297 — 28 1,325 Trading securities measured at net asset value (2) 631 Derivative financial instruments: Interest rate contracts 36 5,729 21 5,786 Foreign exchange contracts 9 1,927 23 1,959 Equity-related contracts 58 63 4 125 Credit-related contracts — 16 2 18 Other contracts 2 4 10 16 Available-for-sale Japanese government bonds 10,902 995 — 11,897 Japanese local government bonds — 210 — 210 U.S. Treasury bonds and federal agency securities 1,009 — — 1,009 Other foreign government bonds 456 886 — 1,342 Agency mortgage-backed securities — 544 — 544 Residential mortgage-backed securities — 61 40 101 Commercial mortgage-backed securities — — 500 500 Japanese corporate bonds and other debt securities — 1,629 120 1,749 Foreign corporate bonds and other debt securities — 678 103 781 Equity securities (3) Equity securities with readily determinable fair values 3,633 135 — 3,768 Equity securities measured at net asset value (2) 53 Other investments — — 35 35 Total assets measured at fair value on a recurring basis 22,753 17,629 1,941 43,007 Liabilities: Trading securities sold, not yet purchased 2,380 199 1 2,580 Derivative financial instruments: Interest rate contracts 38 5,564 8 5,610 Foreign exchange contracts 11 1,746 1 1,758 Equity-related contracts 82 51 9 142 Credit-related contracts — 16 1 17 Other contracts 1 4 9 14 Long-term debt (4) — 1,778 655 2,433 Total liabilities measured at fair value on a recurring basis 2,512 9,358 684 12,554 Notes: (1) Trading securities include foreign currency denominated securities for which the MHFG Group elected the fair value option. (2) 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, 2018 and 2019 were ¥31 billion and ¥37 billion, respectively. (3) The MHFG Group adopted ASU No.2016-01 available-for-sale (4) Amounts represent items for which the Group elected the fair value option or for which it applied the practicability exception.
Reconciliation for All Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3)	The following table presents a reconciliation for all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the fiscal years ended March 31, 2018 and 2019: 2018 April 1, Gains Gains Transfers Transfers Purchases Sales Issuances Settle- March 31, 2018 Change in (losses) (6) (in billions of yen) Assets: Trading securities: Residential mortgage-backed securities 15 — (2) — — — — — — (3 ) 12 — Corporate bonds and 1,052 (20 ) (2) — 123 (241 ) 1,082 (631 ) — (352 ) 1,013 (19 ) Equity securities 23 (1 ) (2) — — — 2 (1 ) — — 23 — Derivative financial instruments, (1) Interest rate contracts 26 (6 ) (2) — — — — — — 1 21 (1 ) Foreign exchange contracts 8 2 (2) — — — — — — 2 12 5 Equity-related contracts (25 ) 1 (2) — — — — — — 28 4 12 Credit-related contracts — — (2) — — — — — — 1 1 — Other contracts — (1 ) (2) — — — — — — 1 — — Available-for-sale Residential mortgage-backed securities 77 — (3) — (4) — — 3 (6 ) — (20 ) 54 — Commercial mortgage-backed securities 224 — (3) 3 (4) — — 286 (69 ) — (3 ) 441 — Japanese corporate bonds and other debt securities 174 11 (3) (10 ) (4) — — 17 — — (29 ) 163 11 Foreign corporate bonds and other debt securities 110 — (3) (1 ) (4) 15 (46 ) 2 — — — 80 — Other investments 37 — (3) — — — 14 (3 ) — (10 ) 38 — Liabilities: Trading securities sold, not yet purchased — — (2) — — — (146 ) 150 — — 4 — Long-term debt 593 3 (5) — 1 (10 ) — — 151 (171 ) 561 5 2019 April 1, Gains Gains Transfers Transfers Purchases Sales Issuances Settle- March 31, 2019 Change in (losses) (6) (in billions of yen) Assets: Trading securities: Residential mortgage-backed securities 12 — (2) — — — — — — (1 ) 11 — Corporate bonds and 1,013 1 (2) — — — 762 (378 ) — (354 ) 1,044 8 Equity securities 23 1 (2) — — — 7 (3 ) — — 28 (1 ) Derivative financial instruments, net (1) Interest rate contracts 21 (11 ) (2) — — — — — — 3 13 (5 ) Foreign exchange contracts 12 15 (2) — — — — — — (5 ) 22 14 Equity-related contracts 4 (15 ) (2) — — — — — — 6 (5 ) 3 Credit-related contracts 1 (2 ) (2) — — — — — — 2 1 1 Other contracts — 1 (2) — — — — — — — 1 1 Available-for-sale Residential mortgage-backed securities 54 — (3) — (4) — — — — — (14 ) 40 — Commercial mortgage-backed securities 441 — (3) 1 (4) — — 144 (72 ) — (14 ) 500 — Japanese corporate bonds and other debt securities 163 37 (3) (33 ) (4) — — 29 (7 ) — (69 ) 120 19 Foreign corporate bonds and other debt securities 80 — (3) (1 ) (4) 61 (42 ) 27 — — (22 ) 103 — Other investments 38 5 (3) — — — 13 (6 ) — (15 ) 35 (2 ) Liabilities: Trading securities sold, not yet purchased 4 1 (2) — — — (35 ) 33 — — 1 — Long-term debt 561 (6 ) (5) 10 (4) 7 — — — 192 (101 ) 655 5 Notes: (1) Total Level 3 derivative exposures have been netted on the table for presentation purposes only. (2) Gains (losses) in Earnings are reported in Trading account gains (losses)—net, Foreign exchange gains (losses)—net or Other noninterest income (expenses). (3) Gains (losses) in Earnings are reported in Investment gains (losses)—net. (4) Gains (losses) in OCI are reported in Other comprehensive income (loss). (5) Gains (losses) in Earnings are reported in Other noninterest income (expenses). (6) Amounts represent total gains or losses recognized in earnings during the period. These gains or losses were attributable to the change in fair value relating to assets and liabilities classified as Level 3 that were still held at March 31, 2018 and 2019.
Quantitative Information about Significant Unobservable Inputs Related to Material Classes of Level 3 Assets and Liabilities	The following table presents information about significant unobservable inputs related to the MHFG Group’s material classes of Level 3 assets and liabilities at March 31, 2018 and 2019: 2018 Products/Instruments Fair value Principal valuation technique Unobservable inputs Range of input values Weighted average (5) (in billions of yen, except for percentages and basis points) Trading securities and Available-for-sale Residential mortgage-backed securities 66 Discounted cash flow Prepayment rate 3%–17% 7% Price-based Default rate 0%–1% 0% Recovery rate 100%–100% 100% Discount margin 17bps–170bps 50bps Commercial mortgage-backed 441 Discounted cash flow Price-based Discount margin 9bps–141bps 28bps Corporate bonds and other debt 1,256 Discounted cash flow Prepayment rate (1) 26%–37% 36% Price-based Default rate (1) 1%–2% 2% Recovery rate (1) 60%–69% 68% Discount margin (1) 12bps–1,165bps 115bps Discount margin (2) 5bps–1,064bps 379bps Derivative financial instruments, net: Interest rate contracts 21 Internal valuation model (3) IR – IR correlation 23%–100% Default rate (4) 0%–63% Foreign exchange contracts 12 Internal valuation model (3) FX – IR correlation 16%–53% FX – FX correlation 61%–61% Default rate (4) 0%–63% Equity-related contracts 4 Internal valuation model (3) Equity – IR correlation 25%–25% Equity volatility 12%–41% Credit-related contracts 1 Internal valuation model (3) Default rate 0%–3% Credit correlation 27%–100% Long-term debt 561 Internal valuation model (3) IR – IR correlation 23%–100% FX – IR correlation 9%–53% FX – FX correlation 61%–61% Equity – IR correlation 25%–25% Equity – FX correlation 55%–70% Equity correlation 24%–100% Equity volatility 13%–56% Default rate 0%–2% Credit correlation 28%–100% 2019 Products/Instruments Fair value Principal valuation technique Unobservable inputs Range of input values Weighted average (5) (in billions of yen, except for percentages and basis points) Trading securities and Available-for-sale Residential mortgage- 51 Discounted cash flow Prepayment rate 4%–19% 8% Price-based Default rate 0%–1% 0% Recovery rate 100%–100% 100% Discount margin 18bps–170bps 51bps Commercial mortgage-backed 500 Discounted cash flow Price-based Discount margin 9bps–161bps 24bps Corporate bonds and other debt 1,267 Discounted cash flow Prepayment rate (1) 22%–22% 22% Price-based Default rate (1) 2%–2% 2% Recovery rate (1) 69%–69% 69% Discount margin (1) 48bps–1,173bps 134bps Discount margin (2) 4bps–1,063bps 295bps Derivative financial instruments, net: Interest rate contracts 13 Internal valuation model (3) IR – IR correlation 23%–100% Default rate (4) 0%–63% Foreign exchange contracts 22 Internal valuation model (3) FX – IR correlation 9%–55% FX – FX correlation 63%–63% Default rate (4) 0%–63% Equity-related contracts (5 ) Internal valuation model (3) Equity – IR correlation 25%–25% Equity correlation 40%–100% Equity volatility 5%–36% Credit-related contracts 1 Internal valuation model (3) Default rate 0%–5% Credit correlation 29%–100% Long-term debt 655 Internal valuation model (3) IR – IR correlation 23%–100% FX – IR correlation 9%–55% FX – FX correlation 63%–63% Equity – IR correlation 25%–25% Equity – FX correlation 55%–88% Equity correlation 12%–100% Equity volatility 5%–49% Default rate 0%–4% Credit correlation 20%–100% 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) This input represents the counterparty default rate derived from the MHFG Group’s own internal credit analyses. (5) Weighted averages are calculated by weighting each input by the relative fair value of the respective financial instruments.
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, 2018 and 2019: 2018 Total Level 1 Level 2 Level 3 Aggregate cost (in billions of yen) Assets: Loans 113 — — 113 164 Loans held-for-sale 60 — 60 — 74 Equity securities (without readily determinable fair values) 1 — — 1 3 Premises and equipment—net — — — — 4 Total assets measured at fair value on a nonrecurring basis 174 — 60 114 245 2019 Total Level 1 Level 2 Level 3 Aggregate cost (in billions of yen) Assets: Loans 125 — 41 84 177 Loans held-for-sale 3 — 3 — 3 Equity securities (without readily determinable fair values) 1 — — 1 1 Other investments 98 98 — — 104 Premises and equipment—net 9 — 4 5 34 Intangible assets — — — — 1 Total assets measured at fair value on a nonrecurring basis 236 98 48 90 320 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, 2018 and 2019, 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 840, “Leases” (“ASC 840”): 2018 Carrying Estimated fair value Total Level 1 Level 2 Level 3 (in billions of yen) Financial assets: Cash and due from banks, interest-bearing deposits in other banks, call loans and funds sold, and receivables under resale agreements and securities borrowing transactions 61,381 61,381 1,206 60,175 — Investments 2,518 2,522 1,984 538 — Loans, net of allowance for loan losses (Note) 83,088 84,041 — — 84,041 Financial liabilities: Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions 43,921 43,921 22,898 21,023 — Interest-bearing deposits 113,558 113,540 61,719 51,821 — Due to trust accounts 3,993 3,993 — 3,993 — Other short-term borrowings 1,688 1,688 — 1,688 — Long-term debt 10,970 10,995 — 10,098 897 2019 Carrying Estimated fair value Total Level 1 Level 2 Level 3 (in billions of yen) Financial assets: Cash and due from banks, interest-bearing deposits in other banks, call loans and funds sold, and receivables under resale agreements and securities borrowing transactions 62,012 62,012 873 61,139 — Investments 1,604 1,609 1,140 469 — Loans, net of allowance for loan losses (Note) 82,382 83,490 — — 83,490 Financial liabilities: Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions 44,918 44,918 24,983 19,935 — Interest-bearing deposits 112,658 112,655 55,542 57,113 — Due to trust accounts 312 312 — 312 — Other short-term borrowings 1,995 1,995 — 1,995 — Long-term debt 9,096 9,178 — 8,336 842 Note: Loans, net of allowance for loan losses include items measured at fair value on a nonrecurring basis.

Offsetting of financial asset_2

Offsetting of financial assets and financial liabilities (Tables)	12 Months Ended
	Mar. 31, 2019
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, 2018 and 2019. 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 Net amounts presented on the (2) Financial instruments ( 4 ) Cash collateral Net (in billions of yen) 2018 Assets (1) Derivatives 9,341 — 9,341 (7,751 ) (520 ) 1,070 Receivables under resale agreements 7,804 — 7,804 (7,763 ) — 41 Receivables under securities borrowing transactions 3,904 — 3,904 (3,874 ) — 30 Total 21,049 — 21,049 (19,388 ) (520 ) 1,141 Liabilities (1) Derivatives 9,013 — 9,013 (7,758 ) (884 ) 371 Payables under repurchase agreements 15,964 — 15,964 (15,847 ) — 117 Payables under securities lending transactions 1,181 — 1,181 (1,179 ) — 2 Total 26,158 — 26,158 (24,784 ) (884 ) 490 2019 Assets (1) Derivatives 7,403 — 7,403 (5,903 ) (528 ) 972 Receivables under resale agreements 12,589 — 12,589 (12,579 ) — 10 Receivables under securities borrowing transactions 1,921 — 1,921 (1,894 ) — 27 Total 21,913 — 21,913 (20,376 ) (528 ) 1,009 Liabilities (1) Derivatives 6,978 — 6,978 (5,766 ) (769 ) 443 Payables under repurchase agreements 14,312 — 14,312 (14,309 ) — 3 Payables under securities lending transactions 932 — 932 (931 ) — 1 Total 22,222 — 22,222 (21,006 ) (769 ) 447 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.

Repurchase agreements and sec_2

Repurchase agreements and securities lending transactions accounted for as secured borrowings (Tables)	12 Months Ended
	Mar. 31, 2019
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, 2018 and 2019: Overnight and Up to 30 days 31-90 days Greater than Total (in billions of yen) 2018 Repurchase agreements 255 11,669 3,676 1,057 16,657 Securities lending transactions 1,270 355 — 208 1,833 Total 1,525 12,024 3,676 1,265 18,490
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, 2018 and 2019: Repurchase Securities lending (in billions of yen) 2018 Japanese government bonds and Japanese local government bonds 1,358 592 Foreign government bonds and foreign agency mortgage-backed securities 14,426 303 Commercial paper and corporate bonds 328 48 Equity securities 406 869 Other 139 21 Total (Note) 16,657 1,833 2019 Japanese government bonds and Japanese local government bonds 2,118 430 Foreign government bonds and foreign agency mortgage-backed securities 11,613 396 Commercial paper and corporate bonds 223 52 Equity securities 492 902 Other 194 18 Total (Note) 14,640 1,798 Note: Amounts exceeded the gross amounts recognized in Note 29 “Offsetting of financial assets and financial liabilities” by ¥1,345 billion and ¥1,194 billion, at March 31, 2018 and 2019, respectively, which excluded the amounts relating to master netting agreements or similar agreements where the MHFG Group did not have the legal right of set-off

Business segment information (T

Business segment information (Tables)	12 Months Ended
	Mar. 31, 2019
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, MHFG (Consolidated) 2017 ( 4 ) Retail & Corporate & Global Global Asset Others (3) Total (in billions of yen) Gross profits + Net gains (losses) related to ETFs and others (1) 716.7 438.3 339.4 549.3 48.8 36.7 2,129.2 General and administrative expenses 719.3 199.9 239.2 191.2 29.3 31.4 1,410.3 Equity in earnings (losses) of equity method investees—net 14.9 1.0 0.9 — 0.5 1.6 18.9 Amortization of goodwill and others 0.4 0.4 0.4 2.3 4.0 2.7 10.2 Others — — — — — (27.7 ) (27.7 ) Net business profits (losses) (2) 11.9 239.0 100.7 355.8 16.0 (23.5 ) 699.9 MHFG (Consolidated) 2018 ( 4 ) Retail & Corporate & Global Global Asset Others ( 3) Total (in billions of yen) Gross profits + Net gains (losses) related to ETFs and others (1) 726.9 431.4 340.7 389.2 50.1 57.3 1,995.6 General and administrative expenses 724.8 202.5 250.9 201.2 27.6 37.2 1,444.2 Equity in earnings (losses) of equity method investees—net 12.7 1.0 2.3 — 2.9 2.6 21.5 Amortization of goodwill and others 0.4 0.4 0.4 2.3 8.0 2.4 13.9 Others — — — — — (21.0 ) (21.0 ) Net business profits (losses) (2) 14.4 229.5 91.7 185.7 17.4 (0.7 ) 538.0 MHFG (Consolidated) 2019 ( 4 ) Retail & Corporate & Global Global Asset Others (3) Total (in billions of yen) Gross profits + Net gains (losses) related to ETFs and others (1) 707.2 473.8 416.1 192.0 49.7 (11.1 ) 1,827.7 General and administrative expenses 713.7 198.2 251.8 203.3 27.3 46.3 1,440.6 Equity in earnings (losses) of equity method investees—net 18.1 0.9 7.3 — 1.3 23.6 51.2 Amortization of goodwill and others 0.4 0.4 0.4 2.3 8.0 2.1 13.6 Others — — — — — (16.3 ) (16.3 ) Net business profits (losses) (2) 11.2 276.1 171.2 (13.6 ) 15.7 (52.2 ) 408.4 Fixed assets ( 5 ) 499.3 225.8 176.9 92.6 0.1 662.5 1,657.2 Notes: (1) “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 and net gains (losses) on operating investment securities of MHSC on its consolidated basis. For the fiscal years ended March 31, 2017, 2018 and 2019, net gains related to ETFs and others amounted to ¥36.5 billion, ¥80.2 billion and ¥15.0 billion, respectively, of which ¥32.6 billion, ¥70.1 billion and ¥7.3 billion, respectively, are included in “Global Markets Company”. (2) Net business profits 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 plus equity in earnings (losses) of equity method investees—net and others. Measurement of net business profits is required for regulatory reporting to the Financial Services Agency. (3) “Others” includes items which should be eliminated as internal transactions between each segment on a consolidated basis. (4) Beginning on April 1, 2018, new allocation methods for income and expense transactions between each segment and “Others” have been applied. In connection with the use of the new allocation methods, the presentation of “Net business profits” has changed to “Net business profits (losses) + Net gains (losses) related to ETFs and others”. Before the change, “Net gains (losses) related to ETFs and others” were included in “Gross profits” of each segment and eliminated in “Others”. In addition, “Amortization of goodwill and others” has been presented as a new item. Figures for the fiscal years ended March 31, 2017 and 2018 have been restated for the new allocation methods. These changes more appropriately reflect the performance of each of the operating segments in accordance with internal managerial accounting rules and practices. Furthermore, income and expense of foreign branches of MHBK and foreign subsidiaries with functional currency other than Japanese Yen have been translated for purposes of segment reporting using the budgeted foreign currency rates. Prior period comparative amounts for these foreign currency income and expense have been translated using current period budgeted foreign currency rates. (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,
Reconciliation of Total Net Business Profits under Internal Management Reporting Systems to Income Before Income Tax Expense on Consolidated Statements of Income	A reconciliation of “Net business profits (losses) + Net gains (losses) related to ETFs and others” for the fiscal years ended March 31, 2017, 2018 and 2019 presented above to income before income tax expense shown on the consolidated statements of income and a reconciliation of “Fixed assets” for the fiscal year ended March 31, 2019 to the total amount of Premises and equipment-net, 2017 2018 2019 (in billions of yen) Net business profits (losses) + Net gains (losses) related to ETFs and others 699.9 538.0 408.4 Adjustment to reconcile management reporting to Japanese GAAP: General and administrative expenses (non-recurring losses) (46.7 ) (30.9 ) 23.3 Expenses related to portfolio problems (including reversal of (provision for) general reserve for losses on loans) (80.2 ) (17.0 ) (30.7 ) Gains on reversal of reserves for possible losses on loans, and others 32.7 173.3 11.2 Net gains (losses) related to stocks - Net gains (losses) related to ETFs and others 205.7 191.9 259.9 Net extraordinary gains (losses) 46.7 17.5 (497.9 ) Others (73.9 ) (72.8 ) (57.9 ) Income before income tax expense under Japanese GAAP 784.2 800.0 116.3 Adjustment to reconcile Japanese GAAP to U.S. GAAP: Derivative financial instruments and hedging activities (221.9 ) (110.2 ) 45.3 Investments (115.9 ) 98.1 (273.3 ) Loans 2.5 (2.4 ) (11.9 ) Allowances for loan losses and off-balance-sheet instruments (13.8 ) 6.8 (5.8 ) Premises and equipment 28.6 35.4 303.6 Land revaluation 4.5 3.4 10.2 Business combinations 14.8 15.6 (12.8 ) Pension liabilities 33.8 (4.4 ) (32.2 ) Consolidation of variable interest entities 1.6 2.7 (39.0 ) Foreign currency translation (6.2 ) 12.1 1.7 Others (31.8 ) (17.8 ) (17.0 ) Income before income tax expense under U.S. GAAP 480.4 839.3 85.1
Reconciliation of Assets from Segment to Consolidated	2019 (in billions of yen) Fixed assets 1,657.2 U.S. GAAP adjustments 413.1 Premises and equipment-net, Goodwill, and Intangible assets 2,070.3 Note: The U.S. GAAP adjustments are primarily comprised of GAAP differences mainly from internally developed software, which was impaired under Japanese GAAP; land, which was revalued under Japanese GAAP; and the consolidation of certain variable interest entities, which are not consolidated under Japanese GAAP.

Foreign activities (Tables)

Foreign activities (Tables)	12 Months Ended
	Mar. 31, 2019
Consolidated Income Statement and Total Assets Information by Major Geographic Area	The following table presents consolidated income statement and total assets information by major geographic area. Foreign activities are defined as business transactions that involve customers residing outside of Japan. However, as the MHFG Group’s operations are highly integrated globally, estimates and assumptions have been made for an allocation among the geographic areas. Americas Japan United Others Europe Asia/Oceania and others Total (in billions of yen) Fiscal year ended March 31, 2017: Total revenue (1) 1,748.3 500.3 70.3 190.7 367.5 2,877.1 Total expenses (2) 1,712.3 303.2 29.1 136.2 215.9 2,396.7 Income before income tax expense 36.0 197.1 41.2 54.5 151.6 480.4 Net income 5.7 167.6 38.8 39.5 137.5 389.1 Total assets at end of fiscal year 138,832.3 30,262.0 4,203.3 10,629.1 16,529.6 200,456.3 Fiscal year ended March 31, 2018: Total revenue (1) 2,002.4 654.9 64.0 197.4 447.8 3,366.5 Total expenses (2) 1,582.5 478.8 38.5 172.6 254.8 2,527.2 Income before income tax expense 419.9 176.1 25.5 24.8 193.0 839.3 Net income 231.3 152.7 23.7 21.3 172.7 601.7 Total assets at end of fiscal year 142,587.8 28,135.9 4,380.4 11,677.8 17,473.7 204,255.6 Fiscal year ended March 31, 2019: Total revenue (1) 1,705.5 792.1 66.0 249.7 616.5 3,429.8 Total expenses (2) 2,082.6 696.5 46.1 203.2 316.3 3,344.7 Income before income tax expense (377.1 ) 95.6 19.9 46.5 300.2 85.1 Net income (331.4 ) 85.3 17.0 34.6 270.2 75.7 Total assets at end of fiscal year 133,443.5 25,913.5 4,824.7 15,322.5 18,107.0 197,611.2 Notes: (1) Total revenue is comprised of Interest and dividend income and Noninterest income. (2) Total expenses are comprised of Interest expense, Provision (credit) for loan losses and Noninterest expenses.

Mizuho Financial Group, Inc.,_2

Mizuho Financial Group, Inc., parent company (Tables)	12 Months Ended
	Mar. 31, 2019
Condensed Balance Sheets	Condensed balance sheets 2018 2019 (in millions of yen) Assets: Cash and due from banks 22,264 99,209 Interest-bearing deposits in other banks 1,227 1,158 Trading account assets 176,593 — Investments in subsidiaries and affiliated companies 9,501,633 9,317,387 Long-term loans receivable from subsidiaries 3,969,015 5,110,248 Other 344,065 351,951 Total 14,014,797 14,879,953 Liabilities and shareholders’ equity: Short-term borrowings 1,083,135 945,505 Long-term debt 3,969,015 5,145,286 Other liabilities 94,226 62,643 Shareholders’ equity 8,868,421 8,726,519 Total 14,014,797 14,879,953
Condensed Statements of Income	Condensed statements of income 2017 2018 2019 (in millions of yen) Income: Dividends from subsidiaries and affiliated companies: Banking subsidiaries 300,530 227,057 267,724 Non-banking 27,618 28,987 23,392 Management fees from subsidiaries 48,594 47,945 39,292 Interest income on loans and discounts 39,359 68,869 106,920 Other income 21,054 52,672 9,575 Total 437,155 425,530 446,903 Expenses: Operating expenses 38,927 38,661 40,680 Interest expense 48,594 74,227 110,861 Other expense 14,608 28,123 59,049 Total 102,129 141,011 210,590 Equity in undistributed net income (loss) of subsidiaries 32,595 309,210 (173,142 ) Income before income tax expense 367,621 593,729 63,171 Income tax expense (benefit) 5,181 16,121 (21,300 ) Net income 362,440 577,608 84,471
Condensed Statements of Cash Flows	Condensed statements of cash flows 2017 2018 2019 (in millions of yen) Cash flows from operating activities: Net income 362,440 577,608 84,471 Adjustments and other (40,595 ) (302,109 ) 197,193 Net cash provided by operating activities 321,845 275,499 281,664 Cash flows from investing activities: Proceeds from sales of Equity securities — — 139,719 Net change in loans (2,022,860 ) (1,344,323 ) (1,075,059 ) Purchases of premises and equipment (40,362 ) (6,649 ) (11,640 ) Payments for purchases of securities of subsidiaries (65,269 ) — — Proceeds from withdrawal of securities of subsidiaries 13,359 — — Net change in other investing activities (5,336 ) (4,114 ) (1,310 ) Net cash used in investing activities (2,120,468 ) (1,355,086 ) (948,290 ) Cash flows from financing activities: Net change in short-term borrowings (30,000 ) (70,000 ) (140,000 ) Proceeds from issuance of long-term debt 2,022,860 1,344,323 1,075,059 Proceeds from issuance of common stock 6 3 3 Purchases of treasury stock (1,435 ) (1,611 ) (2,124 ) Dividends paid (190,031 ) (190,382 ) (190,413 ) Net change in other financing activities 971 555 437 Net cash provided by financing activities 1,802,371 1,082,888 742,962 Effect of exchange rate changes on cash and cash equivalents — — 540 Net increase (decrease) in cash and cash equivalents 3,748 3,301 76,876 Cash and cash equivalents at beginning of period 16,442 20,190 23,491 Cash and cash equivalents at end of period 20,190 23,491 100,367

Subsequent events (Tables)

Subsequent events (Tables)	12 Months Ended
	Mar. 31, 2019
Summary of Redeemed Preferred Securities	The following table describes the details of the redeemed preferred securities: Issuer Aggregate redemption amount Reason for the redemption (in millions) Mizuho Capital Investment (JPY) 3 Limited Series A ¥249,500 Arrival of optional redemption date Mizuho Capital Investment (JPY) 3 Limited Series B ¥53,500 Arrival of optional redemption date

Basis of Presentation and Sum_4

Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017	Sep. 30, 2018
Significant Accounting Policies [Line Items]
Total assets	¥ 197,611,195	¥ 204,255,642	¥ 200,456,300
Accounting Standards Update 2016-18
Significant Accounting Policies [Line Items]
Change in net cash for operating activities		3,415	4,181
Change in net cash for investing activities		762,722	¥ 10,689,241
Minimum
Significant Accounting Policies [Line Items]
Period in which obligors generally determined to be substantially bankrupt, past due (in months)	6 months
Minimum | Impaired loans
Significant Accounting Policies [Line Items]
Number of days past due	90 days
Software and Software Development Costs | Minimum
Significant Accounting Policies [Line Items]
Estimated useful life	5 years
Software and Software Development Costs | Maximum
Significant Accounting Policies [Line Items]
Estimated useful life	10 years
Shinko Securities Company Limited | Customer relationships
Significant Accounting Policies [Line Items]
Weighted-average amortization period	16 years
Trust and Custody Services Bank Ltd.
Significant Accounting Policies [Line Items]
Total assets		¥ 14,000,000		¥ 9,000,000
Voting equity interests		27.00%
Asset Management Company | Customer relationships
Significant Accounting Policies [Line Items]
Weighted-average amortization period	16 years 10 months 25 days

Basis of Presentation and Sum_5

Basis of Presentation and Summary of Significant Accounting Policies (Useful Lives of Premises and Equipment) (Detail)	12 Months Ended
	Mar. 31, 2019
Buildings | Minimum
Property, Plant, and Equipment Disclosure [Line Items]
Years	3 years
Buildings | Maximum
Property, Plant, and Equipment Disclosure [Line Items]
Years	50 years
Equipment and furniture | Minimum
Property, Plant, and Equipment Disclosure [Line Items]
Years	2 years
Equipment and furniture | Maximum
Property, Plant, and Equipment Disclosure [Line Items]
Years	20 years
Leasehold improvements | Minimum
Property, Plant, and Equipment Disclosure [Line Items]
Years	3 years
Leasehold improvements | Maximum
Property, Plant, and Equipment Disclosure [Line Items]
Years	50 years

Recently Issued Accounting Pr_2

Recently Issued Accounting Pronouncements - Additional Information (Detail) - JPY (¥) ¥ in Millions	Apr. 01, 2018	Mar. 31, 2018		Mar. 31, 2017	Apr. 01, 2016
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principles, net of tax		¥ 1,540,317			¥ (329)
Accumulated Other Comprehensive Income
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principles, net of tax		(1,535,142)	[1]		¥ 330
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating assets, right of use assets		600,000
Operating assets, lease liabilities		¥ 600,000
ASU No.2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Equity securities	¥ 5,000
ASU No.2016-01 | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principles, net of tax	1,545,000
ASU No.2016-01 | Retained Earnings | Equity Method Investments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principles, net of tax	1,530,000
ASU No.2016-01 | Accumulated Other Comprehensive Income
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principles, net of tax	¥ 10,000
ASU No. 2015-02 | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principles, net of tax				¥ (329)
ASU No. 2015-02 | Accumulated Other Comprehensive Income
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principles, net of tax				¥ 330
[1]	See Note 2 "Recently issued accounting pronouncements" for further details of the cumulative-effect adjustment for AOCI.

Business Combination - Addition

Business Combination - Additional Information (Detail) ¥ in Millions	Oct. 01, 2016JPY (¥)shares
MHAM
Business Acquisition [Line Items]
Interests exchanged	30.00%
Remeasurement gain recognized	¥ 23,829
Percentage of equity held by acquirer immediately before acquisition	30.00%
DIAM
Business Acquisition [Line Items]
Fair value of MHFG's equity interests in DIAM held before the business combination	¥ 72,106
Common shares of MHAM | shares	1,038,408
Fair value of total consideration transferred	¥ 28,842
Fair value, noncontrolling interest	43,264
Remeasurement gain recognized	¥ 56,226
Percentage of equity held by acquirer immediately before acquisition	50.00%
Asset Management One
Business Acquisition [Line Items]
Percentage of shareholding ratio based on voting rights	51.00%
Percentage of shareholding ratio based on economic interests	70.00%

Business Combination - (Summary

Business Combination - (Summary of Consideration Paid for DIAM, Amounts of Acquired Assets and Assumed Liabilities Recognized and Fair Value of Noncontrolling Interest at Acquisition Date in DIAM) (Detail) - JPY (¥) ¥ in Millions		Oct. 01, 2016	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017	Apr. 01, 2016
Recognized amounts of identifiable assets acquired:
Cash and due from banks					¥ 1,095
Recognized amounts of identifiable liabilities assumed:
Goodwill			¥ 95,151	¥ 95,184	¥ 95,176	¥ 19,097
DIAM
Consideration:
Equity instruments (1,038,408 common shares of MHAM)		¥ 28,842
Fair value of total consideration transferred		28,842
Fair value of equity interests in DIAM held by MHFG before the business combination		72,106
Business Combination, Consideration Transferred, Including Equity Interest in Acquiree Held Prior to Combination, Total		100,948
Recognized amounts of identifiable assets acquired:
Cash and due from banks		831
Interest-bearing deposits in other banks		12,873
Trading account assets		266
Investments		12,234
Premises and equipment-net		3,546
Accrued income		7,882
Intangible assets	[1]	53,037
Deferred tax assets		1,003
Other assets		2,208
Recognized amounts of identifiable liabilities assumed:
Trading account liabilities		304
Income taxes payable		918
Deferred taxes liabilities		16,238
Accrued expenses		5,392
Other liabilities		3,041
Total identifiable net assets		67,987
Goodwill		76,225
Noncontrolling interest in DIAM		43,264
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest		¥ 100,948
[1]	Amount represents customer relationships subject to amortization, of which the weighted-average amortization period is 16.9 years.

Business Combination - (Summa_2

Business Combination - (Summary of Consideration Paid for DIAM, Amounts of Acquired Assets and Assumed Liabilities Recognized and Fair Value of Noncontrolling Interest at Acquisition Date in DIAM) (Parenthetical) (Detail) - DIAM	Oct. 01, 2016shares
Business Acquisition [Line Items]
Common shares of MHAM	1,038,408
Customer relationships
Business Acquisition [Line Items]
Weighted-average amortization period	16 years 10 months 25 days

Investments (Amortized Cost, Gr

Investments (Amortized Cost, Gross Unrealized Gains and Losses, and Fair Value of Available-for-Sale and Held-to-Maturity Securities) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities		¥ 18,094,439	¥ 21,181,709
Gross unrealized gains, available-for-sale securities		45,923	2,521,529
Gross unrealized losses, available-for-sale securities		6,446	37,610
Fair value, available-for-sale securities		18,133,916	23,665,628
Amortized cost, held-to-maturity securities		1,604,104	2,517,551
Gross unrealized gains, held-to-maturity securities		19,907	24,472
Gross unrealized losses, held-to-maturity securities		14,423	20,177
Total		1,609,588	2,521,846
Debt securities | Japanese government bonds
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities		11,888,510	13,334,619
Gross unrealized gains, available-for-sale securities		11,259	7,332
Gross unrealized losses, available-for-sale securities		2,998	9,656
Fair value, available-for-sale securities		11,896,771	13,332,295
Amortized cost, held-to-maturity securities		1,119,899	1,959,910
Gross unrealized gains, held-to-maturity securities		19,907	24,472
Total		1,139,806	1,984,382
Debt securities | Japanese local government bonds
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities		208,308	236,711
Gross unrealized gains, available-for-sale securities		1,671	2,903
Gross unrealized losses, available-for-sale securities		87	280
Fair value, available-for-sale securities		209,892	239,334
Debt securities | U.S. Treasury bonds and federal agency securities
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities		1,008,903	689,297
Gross unrealized gains, available-for-sale securities		644	109
Gross unrealized losses, available-for-sale securities		231	3,557
Fair value, available-for-sale securities		1,009,316	685,849
Debt securities | Other foreign government bonds
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities		1,341,564	1,057,852
Gross unrealized gains, available-for-sale securities		758	1,043
Gross unrealized losses, available-for-sale securities		455	1,102
Fair value, available-for-sale securities		1,341,867	1,057,793
Debt securities | Agency mortgage-backed securities
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities	[1]	530,540	882,686
Gross unrealized gains, available-for-sale securities	[1]	14,524	13,356
Gross unrealized losses, available-for-sale securities	[1],[2]	593	7,628
Fair value, available-for-sale securities	[1]	544,471	888,414
Amortized cost, held-to-maturity securities	[3]	484,205	557,641
Gross unrealized losses, held-to-maturity securities	[3]	14,423	20,177
Total	[3]	469,782	537,464
Debt securities | Residential mortgage-backed securities
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities		99,904	117,870
Gross unrealized gains, available-for-sale securities		1,420	1,264
Gross unrealized losses, available-for-sale securities		191	281
Fair value, available-for-sale securities		101,133	118,853
Debt securities | Commercial mortgage-backed securities
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities		495,313	437,115
Gross unrealized gains, available-for-sale securities		4,914	4,132
Gross unrealized losses, available-for-sale securities		104	323
Fair value, available-for-sale securities		500,123	440,924
Debt securities | Japanese corporate bonds and other debt securities
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities	[4]	1,743,309	1,950,947
Gross unrealized gains, available-for-sale securities	[4]	7,686	40,290
Gross unrealized losses, available-for-sale securities	[4]	1,561	1,410
Fair value, available-for-sale securities	[4]	1,749,434	1,989,827
Debt securities | Foreign corporate bonds and other debt securities
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities	[5]	778,088	879,506
Gross unrealized gains, available-for-sale securities	[5]	3,047	1,927
Gross unrealized losses, available-for-sale securities	[5]	226	2,082
Fair value, available-for-sale securities	[5]	¥ 780,909	879,351
Equity securities (marketable)
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities	[6]		1,595,106
Gross unrealized gains, available-for-sale securities	[6]		2,449,173
Gross unrealized losses, available-for-sale securities	[6]		11,291
Fair value, available-for-sale securities	[6]		¥ 4,032,988
[1]	Agency mortgage-backed securities presented in this line consist of Japanese and Foreign agency mortgage-backed securities, of which the fair values were ¥742,565 million and ¥145,849 million, respectively, at March 31, 2018, and ¥517,330 million and ¥27,141 million, respectively, at March 31, 2019. All Japanese agency mortgage-backed securities are issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise. Foreign agency mortgage-backed securities primarily consist of Government National Mortgage Association ("Ginnie Mae") securities, which are guaranteed by the United States government.
[2]	Agency mortgage-backed securities presented in this line consist of Japanese and Foreign agency mortgage-backed securities, of which the fair values were ¥88,017 million and ¥145,743 million, respectively, at March 31, 2018, and ¥11,107 million and ¥27,065 million, respectively, at March 31, 2019. 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 Ginnie Mae securities, which are guaranteed by the United States government.
[3]	All Agency mortgage-backed securities presented in this line are Ginnie Mae securities.
[4]	Other debt securities presented in this line primarily consist of Japanese negotiable certificates of deposit ("NCDs"), of which the total fair values were ¥106,101 million at March 31, 2018, and ¥6,725 million at March 31, 2019.
[5]	Other debt securities presented in this line primarily consist of Foreign NCDs and asset-backed securities ("ABS"), of which the total fair values were ¥313,164 million at March 31, 2018, and ¥246,503 million at March 31, 2019.
[6]	The MHFG Group adopted ASU No.2016-01 on April 1, 2018, resulting in a cumulative-effect adjustment from AOCI to Retained earnings for net unrealized gains on equity securities (marketable). The available-for-sale category was eliminated for equity securities effective April 1, 2018. See Note 2 "Recently issued accounting pronouncements" for further details.

Investments (Amortized Cost, _2

Investments (Amortized Cost, Gross Unrealized Gains and Losses, and Fair Value of Available-for-Sale and Held-to-Maturity Securities) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018
Schedule of Investments [Line Items]
Fair value, available-for-sale securities		¥ 18,133,916	¥ 23,665,628
Debt securities | Agency mortgage-backed securities
Schedule of Investments [Line Items]
Fair value, available-for-sale securities	[1]	544,471	888,414
Debt securities | Foreign agency mortgage-backed securities | Agency mortgage-backed securities
Schedule of Investments [Line Items]
Fair value, available-for-sale securities		27,141	145,849
Debt securities | Japanese agency mortgage-backed securities | Agency mortgage-backed securities
Schedule of Investments [Line Items]
Fair value, available-for-sale securities		517,330	742,565
Japanese government and corporate debt securities | Negotiable Certificates of Deposits and Asset- Backed Securities
Schedule of Investments [Line Items]
Fair value, available-for-sale securities		6,725	106,101
Foreign government and corporate debt securities | Negotiable certificates of deposits, asset- backed securities and collateral loan obligations
Schedule of Investments [Line Items]
Fair value, available-for-sale securities		¥ 246,503	¥ 313,164
[1]	Agency mortgage-backed securities presented in this line consist of Japanese and Foreign agency mortgage-backed securities, of which the fair values were ¥742,565 million and ¥145,849 million, respectively, at March 31, 2018, and ¥517,330 million and ¥27,141 million, respectively, at March 31, 2019. 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.

Investments (Amortized Cost and

Investments (Amortized Cost and Fair Value of Available-for-Sale and Held-to-Maturity Securities by Contractual Maturity) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost		¥ 10,534,262
Due after one year through five years, amortized cost		4,043,188
Due after five years through ten years,amortized cost		2,388,238
Due after ten years, amortized cost		1,128,751
Total		18,094,439
Due in one year or less, amortized cost		639,984
Due after one year through five years, amortized cost		379,837
Due after five years through ten years, amortized cost		100,078
Due after ten years, amortized cost		484,205
Amortized cost, held-to-maturity securities		1,604,104	¥ 2,517,551
Due in one year or less, fair value		10,536,287
Due after one year through five years, fair value		4,052,663
Due after five years through ten years, fair value		2,398,496
Due after ten years, fair value		1,146,470
Total		18,133,916
Due in one year or less, fair value		640,928
Due after one year through five years, fair value		395,085
Due after five years through ten years, fair value		103,793
Due after ten years, fair value		469,782
Total		1,609,588	2,521,846
Debt securities | Japanese government bonds
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost		7,839,925
Due after one year through five years, amortized cost		2,326,357
Due after five years through ten years,amortized cost		1,461,333
Due after ten years, amortized cost		260,895
Total		11,888,510
Due in one year or less, amortized cost		639,984
Due after one year through five years, amortized cost		379,837
Due after five years through ten years, amortized cost		100,078
Amortized cost, held-to-maturity securities		1,119,899	1,959,910
Due in one year or less, fair value		7,840,638
Due after one year through five years, fair value		2,329,473
Due after five years through ten years, fair value		1,465,030
Due after ten years, fair value		261,630
Total		11,896,771
Due in one year or less, fair value		640,928
Due after one year through five years, fair value		395,085
Due after five years through ten years, fair value		103,793
Total		1,139,806	1,984,382
Debt securities | Japanese local government bonds
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost		7,229
Due after one year through five years, amortized cost		118,677
Due after five years through ten years,amortized cost		77,336
Due after ten years, amortized cost		5,066
Total		208,308
Due in one year or less, fair value		7,263
Due after one year through five years, fair value		119,115
Due after five years through ten years, fair value		78,275
Due after ten years, fair value		5,239
Total		209,892
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		989,921
Due after one year through five years, amortized cost		18,982
Total		1,008,903
Due in one year or less, fair value		990,029
Due after one year through five years, fair value		19,287
Total		1,009,316
Debt securities | Other foreign government bonds
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost		1,106,386
Due after one year through five years, amortized cost		235,178
Total		1,341,564
Due in one year or less, fair value		1,106,543
Due after one year through five years, fair value		235,324
Total		1,341,867
Debt securities | Agency mortgage-backed securities
Investments Classified by Contractual Maturity Date [Line Items]
Due after ten years, amortized cost		530,540
Total		530,540
Due after ten years, amortized cost		484,205
Amortized cost, held-to-maturity securities	[1]	484,205	557,641
Due after ten years, fair value		544,471
Total		544,471
Due after ten years, fair value		469,782
Total	[1]	469,782	¥ 537,464
Debt securities | Residential mortgage-backed securities
Investments Classified by Contractual Maturity Date [Line Items]
Due after five years through ten years,amortized cost		4,656
Due after ten years, amortized cost		95,248
Total		99,904
Due after five years through ten years, fair value		4,656
Due after ten years, fair value		96,477
Total		101,133
Debt securities | Commercial mortgage-backed securities
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost		9,501
Due after one year through five years, amortized cost		175,819
Due after five years through ten years,amortized cost		282,518
Due after ten years, amortized cost		27,475
Total		495,313
Due in one year or less, fair value		9,518
Due after one year through five years, fair value		177,237
Due after five years through ten years, fair value		285,849
Due after ten years, fair value		27,519
Total		500,123
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		137,824
Due after one year through five years, amortized cost		876,876
Due after five years through ten years,amortized cost		521,851
Due after ten years, amortized cost		206,758
Total		1,743,309
Due in one year or less, fair value		138,670
Due after one year through five years, fair value		878,396
Due after five years through ten years, fair value		524,003
Due after ten years, fair value		208,365
Total		1,749,434
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		443,476
Due after one year through five years, amortized cost		291,299
Due after five years through ten years,amortized cost		40,544
Due after ten years, amortized cost		2,769
Total		778,088
Due in one year or less, fair value		443,626
Due after one year through five years, fair value		293,831
Due after five years through ten years, fair value		40,683
Due after ten years, fair value		2,769
Total		¥ 780,909
[1]	All Agency mortgage-backed securities presented in this line are Ginnie Mae securities.

Investments - Additional Inform

Investments - Additional Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Gain (Loss) on Securities [Line Items]
Equity method Investments, carrying value	¥ 354,268	¥ 280,666
Held-to-maturity Securities
Gain (Loss) on Securities [Line Items]
Impairment loss on securities	¥ 0	0
Orient Corporation
Gain (Loss) on Securities [Line Items]
Percentage of proportionate share to the total outstanding common stock	49.00%
Equity securities (marketable)
Gain (Loss) on Securities [Line Items]
Equity method Investments, carrying value	¥ 201,034	152,445
Equity method Investments, aggregated market values	¥ 308,137	¥ 324,239

Investments (Other-Than-Tempora

Investments (Other-Than-Temporary Impairment Losses on Available-for-Sale Securities) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Gain (Loss) on Securities [Line Items]
Other-than-temporary impairment on available-for-sale securities	¥ 213	¥ 4,095	¥ 12,167
Debt securities
Gain (Loss) on Securities [Line Items]
Other-than-temporary impairment on available-for-sale securities	¥ 213	1,015	138
Equity securities
Gain (Loss) on Securities [Line Items]
Other-than-temporary impairment on available-for-sale securities		¥ 3,080	¥ 12,029

Investments (Gross Unrealized L

Investments (Gross Unrealized Losses and Fair Value of Available-for-Sale and Held-to-Maturity Securities, Aggregated by Length of Time that Individual Securities Have Been in a Continuous Unrealized Loss Position) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		¥ 3,809,946	¥ 10,402,277
Less than 12 months Gross unrealized losses, available-for-sale securities		3,137	22,884
12 months or more Fair value, available-for-sale securities		2,010,191	3,698,632
12 months or more Gross unrealized losses, available-for-sale securities		3,309	14,726
Total Fair value, available-for-sale securities		5,820,137	14,100,909
Total Gross unrealized losses, available-for-sale securities		6,446	37,610
Less than 12 months, Fair value, held-to-maturity securities			30,589
Less than 12 months Gross unrealized losses, held-to-maturity securities			766
12 months or more Fair value, held-to-maturity securities		469,782	506,875
12 months or more Gross unrealized losses, held-to-maturity securities		14,423	19,411
Total Fair value, held-to-maturity securities		469,782	537,464
Total Gross unrealized losses, held-to-maturity securities		14,423	20,177
Debt securities | Japanese government bonds
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		2,296,536	8,052,820
Less than 12 months Gross unrealized losses, available-for-sale securities		1,441	3,716
12 months or more Fair value, available-for-sale securities		1,332,688	2,868,078
12 months or more Gross unrealized losses, available-for-sale securities		1,557	5,940
Total Fair value, available-for-sale securities		3,629,224	10,920,898
Total Gross unrealized losses, available-for-sale securities		2,998	9,656
Debt securities | Japanese local government bonds
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		9,752	28,827
Less than 12 months Gross unrealized losses, available-for-sale securities		32	139
12 months or more Fair value, available-for-sale securities		38,873	58,998
12 months or more Gross unrealized losses, available-for-sale securities		55	141
Total Fair value, available-for-sale securities		48,625	87,825
Total Gross unrealized losses, available-for-sale securities		87	280
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		506,176	515,005
Less than 12 months Gross unrealized losses, available-for-sale securities		231	3,557
Total Fair value, available-for-sale securities		506,176	515,005
Total Gross unrealized losses, available-for-sale securities		231	3,557
Debt securities | Other foreign government bonds
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		438,771	419,648
Less than 12 months Gross unrealized losses, available-for-sale securities		321	1,030
12 months or more Fair value, available-for-sale securities		26,782	68,359
12 months or more Gross unrealized losses, available-for-sale securities		134	72
Total Fair value, available-for-sale securities		465,553	488,007
Total Gross unrealized losses, available-for-sale securities		455	1,102
Debt securities | Agency mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities	[1]	466	45,434
Less than 12 months Gross unrealized losses, available-for-sale securities	[1]	2	1,116
12 months or more Fair value, available-for-sale securities	[1]	37,706	188,326
12 months or more Gross unrealized losses, available-for-sale securities	[1]	591	6,512
Total Fair value, available-for-sale securities	[1]	38,172	233,760
Total Gross unrealized losses, available-for-sale securities	[1],[2]	593	7,628
Less than 12 months, Fair value, held-to-maturity securities	[3]		30,589
Less than 12 months Gross unrealized losses, held-to-maturity securities	[3]		766
12 months or more Fair value, held-to-maturity securities	[3]	469,782	506,875
12 months or more Gross unrealized losses, held-to-maturity securities	[3]	14,423	19,411
Total Fair value, held-to-maturity securities	[3]	469,782	537,464
Total Gross unrealized losses, held-to-maturity securities	[3]	14,423	20,177
Debt securities | Residential mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities			11,336
Less than 12 months Gross unrealized losses, available-for-sale securities			14
12 months or more Fair value, available-for-sale securities		16,729	16,129
12 months or more Gross unrealized losses, available-for-sale securities		191	267
Total Fair value, available-for-sale securities		16,729	27,465
Total Gross unrealized losses, available-for-sale securities		191	281
Debt securities | Commercial mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities		11,256	68,723
Less than 12 months Gross unrealized losses, available-for-sale securities		44	242
12 months or more Fair value, available-for-sale securities		36,760	7,835
12 months or more Gross unrealized losses, available-for-sale securities		60	81
Total Fair value, available-for-sale securities		48,016	76,558
Total Gross unrealized losses, available-for-sale securities		104	323
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		417,825	563,831
Less than 12 months Gross unrealized losses, available-for-sale securities		924	933
12 months or more Fair value, available-for-sale securities		440,937	403,069
12 months or more Gross unrealized losses, available-for-sale securities		637	477
Total Fair value, available-for-sale securities		858,762	966,900
Total Gross unrealized losses, available-for-sale securities	[4]	1,561	1,410
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		129,164	358,410
Less than 12 months Gross unrealized losses, available-for-sale securities		142	888
12 months or more Fair value, available-for-sale securities		79,716	87,472
12 months or more Gross unrealized losses, available-for-sale securities		84	1,194
Total Fair value, available-for-sale securities		208,880	445,882
Total Gross unrealized losses, available-for-sale securities	[5]	¥ 226	2,082
Equity securities (marketable)
Gain (Loss) on Securities [Line Items]
Less than 12 months, Fair value, available-for-sale securities	[6]		338,243
Less than 12 months Gross unrealized losses, available-for-sale securities	[6]		11,249
12 months or more Fair value, available-for-sale securities	[6]		366
12 months or more Gross unrealized losses, available-for-sale securities	[6]		42
Total Fair value, available-for-sale securities	[6]		338,609
Total Gross unrealized losses, available-for-sale securities	[6]		¥ 11,291
[1]	Agency mortgage-backed securities presented in this line consist of Japanese and Foreign agency mortgage-backed securities, of which the fair values were ¥88,017 million and ¥145,743 million, respectively, at March 31, 2018, and ¥11,107 million and ¥27,065 million, respectively, at March 31, 2019. 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 Ginnie Mae securities, which are guaranteed by the United States government.
[2]	Agency mortgage-backed securities presented in this line consist of Japanese and Foreign agency mortgage-backed securities, of which the fair values were ¥742,565 million and ¥145,849 million, respectively, at March 31, 2018, and ¥517,330 million and ¥27,141 million, respectively, at March 31, 2019. 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.
[3]	All Agency mortgage-backed securities presented in this line are Ginnie Mae securities.
[4]	Other debt securities presented in this line primarily consist of Japanese negotiable certificates of deposit ("NCDs"), of which the total fair values were ¥106,101 million at March 31, 2018, and ¥6,725 million at March 31, 2019.
[5]	Other debt securities presented in this line primarily consist of Foreign NCDs and asset-backed securities ("ABS"), of which the total fair values were ¥313,164 million at March 31, 2018, and ¥246,503 million at March 31, 2019.
[6]	The MHFG Group adopted ASU No.2016-01 on April 1, 2018, resulting in a cumulative-effect adjustment from AOCI to Retained earnings for net unrealized gains on equity securities (marketable). The available-for-sale category was eliminated for equity securities effective April 1, 2018. See Note 2 "Recently issued accounting pronouncements" for further details.

Investments (Gross Unrealized_2

Investments (Gross Unrealized Losses and Fair Value of Available-for-Sale and Held-to-Maturity Securities, Aggregated by Length of Time that Individual Securities Have Been in a Continuous Unrealized Loss Position) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018
Gain (Loss) on Securities [Line Items]
Fair value, available-for-sale securities		¥ 5,820,137	¥ 14,100,909
Debt securities | Agency mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Fair value, available-for-sale securities	[1]	38,172	233,760
Debt securities | Japanese agency mortgage-backed securities | Agency mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Fair value, available-for-sale securities		11,107	88,017
Debt securities | Foreign agency mortgage-backed securities | Agency mortgage-backed securities
Gain (Loss) on Securities [Line Items]
Fair value, available-for-sale securities		¥ 27,065	¥ 145,743
[1]	Agency mortgage-backed securities presented in this line consist of Japanese and Foreign agency mortgage-backed securities, of which the fair values were ¥88,017 million and ¥145,743 million, respectively, at March 31, 2018, and ¥11,107 million and ¥27,065 million, respectively, at March 31, 2019. 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 Ginnie Mae securities, which are guaranteed by the United States government.

Investments (Realized Gains and

Investments (Realized Gains and Losses on Sales of Available-for-Sale Securities) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Gross realized gains	¥ 23,777	¥ 314,948	¥ 353,036
Gross realized losses	(26,299)	(41,044)	(21,163)
Net realized gains (losses) on sales of available-for-sale securities	¥ (2,522)	¥ 273,904	¥ 331,873

Investments (Summary of Composi

Investments (Summary of Composition of Other Investments) (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2019	Mar. 31, 2018
Schedule of Investments [Line Items]
Equity method investments	¥ 354,268	¥ 280,666
Investments held by consolidated investment companies	35,472	37,735
Other equity interests		267,495
Total	¥ 389,740	¥ 585,896

Investments - Summary of Detail

Investments - Summary of Details of Net Gains and Losses on Equity Securities (Detail) ¥ in Millions	12 Months Ended
	Mar. 31, 2019JPY (¥)
Gain (Loss) on Securities [Line Items]
Net gains and losses recognized during the period on equity securities	¥ (155,947)
Less: Net gains and losses recognized during the period on equity securities sold during the period	34,034
Unrealized gains and losses recognized during the reporting period on equity securities still held at the reporting period	¥ (189,981)

Investments - Summary of Equity

Investments - Summary of Equity Securities Without Readily Determinable Fair Values (Detail) ¥ in Millions	12 Months Ended
	Mar. 31, 2019JPY (¥)
Equity Securities without Readily Determinable Fair Value [Line Items]
Carrying amounts at the end of the period	¥ 212,270
During the period	1,413
Cumulative	1,413
During the period	2,373
Cumulative	¥ 2,373

Loans (Loans Outstanding by Dom

Loans (Loans Outstanding by Domicile and Industry of Borrower) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[1]	¥ 82,952,090	¥ 83,661,340
Less: Unearned income and deferred loan fees-net		152,147	146,696
Loans outstanding		82,799,943	83,514,644
Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		54,409,144	58,660,514
Domestic | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		9,558,146	8,156,341
Domestic | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		8,954,823	8,101,668
Domestic | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		5,113,386	5,024,018
Domestic | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		5,163,267	5,112,673
Domestic | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		3,622,130	3,564,869
Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		4,303,231	4,471,423
Domestic | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		2,358,904	8,882,125
Domestic | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[2]	5,477,452	5,018,387
Domestic | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		8,950,216	9,445,286
Domestic | Other individual loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		907,589	883,724
Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3]	28,542,946	25,000,826
Foreign | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		9,126,392	7,465,140
Foreign | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		296,872	302,891
Foreign | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		19,086,511	17,195,159
Foreign | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		¥ 33,171	¥ 37,636
[1]	Amounts represent loan balances before deducting unearned income and deferred loan fees.
[2]	Other industries of Domestic includes trade receivables and lease receivables of consolidated VIEs.
[3]	The majority of Total foreign consist of Commercial and Industrial loans.

Loans - Additional Information

Loans - Additional Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net losses on sales of loans	¥ 2,018	¥ 87	¥ 919
Impaired Financing Receivables with No Related Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans partially charged off	¥ 25,097	¥ 29,037

Loans (Credit Quality Informati

Loans (Credit Quality Information of Loans Based on MHFG Group's Internal Rating System) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[1]	¥ 82,952,090	¥ 83,661,340
Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		54,409,144	58,660,514
Domestic | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		9,558,146	8,156,341
Domestic | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		8,954,823	8,101,668
Domestic | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		5,113,386	5,024,018
Domestic | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		5,163,267	5,112,673
Domestic | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		3,622,130	3,564,869
Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		4,303,231	4,471,423
Domestic | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		2,358,904	8,882,125
Domestic | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[2]	5,477,452	5,018,387
Domestic | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		9,857,805	10,329,010
Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3]	28,542,946	25,000,826
Foreign | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		9,126,392	7,465,140
Foreign | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		296,872	302,891
Foreign | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		19,086,511	17,195,159
Foreign | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		33,171	37,636
Financing Receivables Not Impaired | Normal obligors | Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		65,286,588	59,248,942
Financing Receivables Not Impaired | Normal obligors | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	10,372,030	10,883,141
Financing Receivables Not Impaired | Normal obligors | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	5,456,385	11,467,703
Financing Receivables Not Impaired | Normal obligors | Domestic | Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		40,303,480	37,803,998
Financing Receivables Not Impaired | Normal obligors | Domestic | Corporate | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		9,209,834	7,705,495
Financing Receivables Not Impaired | Normal obligors | Domestic | Corporate | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		8,186,308	7,317,972
Financing Receivables Not Impaired | Normal obligors | Domestic | Corporate | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		4,761,724	4,535,793
Financing Receivables Not Impaired | Normal obligors | Domestic | Corporate | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		4,686,541	4,636,236
Financing Receivables Not Impaired | Normal obligors | Domestic | Corporate | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		3,472,991	3,414,781
Financing Receivables Not Impaired | Normal obligors | Domestic | Corporate | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		4,262,125	4,244,101
Financing Receivables Not Impaired | Normal obligors | Domestic | Corporate | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		2,358,899	3,010,708
Financing Receivables Not Impaired | Normal obligors | Domestic | Corporate | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[2]	3,131,072	2,716,502
Financing Receivables Not Impaired | Normal obligors | Domestic | Corporate | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		233,986	222,410
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	10,362,135	10,873,687
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	69,080	77,947
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	505,142	541,778
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	165,643	172,045
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	161,392	177,965
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	71,934	76,532
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	1,534	1,640
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	5
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[2],[4]	2,450	3,536
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	9,384,955	9,822,244
Financing Receivables Not Impaired | Normal obligors | Domestic | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	2,455,064	8,523,806
Financing Receivables Not Impaired | Normal obligors | Domestic | Other | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	19,805	23,343
Financing Receivables Not Impaired | Normal obligors | Domestic | Other | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	15,920	13,332
Financing Receivables Not Impaired | Normal obligors | Domestic | Other | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	3,281	141,718
Financing Receivables Not Impaired | Normal obligors | Domestic | Other | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	26,881	17,305
Financing Receivables Not Impaired | Normal obligors | Domestic | Other | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	934	1,774
Financing Receivables Not Impaired | Normal obligors | Domestic | Other | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	72	196,431
Financing Receivables Not Impaired | Normal obligors | Domestic | Other | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]		5,871,417
Financing Receivables Not Impaired | Normal obligors | Domestic | Other | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[2],[5]	2,323,197	2,170,442
Financing Receivables Not Impaired | Normal obligors | Domestic | Other | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	64,974	88,044
Financing Receivables Not Impaired | Normal obligors | Foreign | Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		24,983,108	21,444,944
Financing Receivables Not Impaired | Normal obligors | Foreign | Corporate | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		8,623,103	6,949,036
Financing Receivables Not Impaired | Normal obligors | Foreign | Corporate | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		296,870	301,072
Financing Receivables Not Impaired | Normal obligors | Foreign | Corporate | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		16,061,655	14,192,930
Financing Receivables Not Impaired | Normal obligors | Foreign | Corporate | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		1,480	1,906
Financing Receivables Not Impaired | Normal obligors | Foreign | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	9,895	9,454
Financing Receivables Not Impaired | Normal obligors | Foreign | Retail | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	182	209
Financing Receivables Not Impaired | Normal obligors | Foreign | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	9,713	9,245
Financing Receivables Not Impaired | Normal obligors | Foreign | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	3,001,321	2,943,897
Financing Receivables Not Impaired | Normal obligors | Foreign | Other | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	492,831	487,978
Financing Receivables Not Impaired | Normal obligors | Foreign | Other | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	2,488,800	2,432,189
Financing Receivables Not Impaired | Normal obligors | Foreign | Other | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	19,690	23,730
Financing Receivables Not Impaired | Watch obligors | Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		999,405	1,091,660
Financing Receivables Not Impaired | Watch obligors | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[6]	145,546	165,250
Financing Receivables Not Impaired | Watch obligors | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5],[6]	46,004	189,384
Financing Receivables Not Impaired | Watch obligors | Domestic | Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		641,554	665,061
Financing Receivables Not Impaired | Watch obligors | Domestic | Corporate | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		141,202	197,465
Financing Receivables Not Impaired | Watch obligors | Domestic | Corporate | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		186,753	172,287
Financing Receivables Not Impaired | Watch obligors | Domestic | Corporate | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		90,578	95,223
Financing Receivables Not Impaired | Watch obligors | Domestic | Corporate | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		127,695	121,832
Financing Receivables Not Impaired | Watch obligors | Domestic | Corporate | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		37,593	35,339
Financing Receivables Not Impaired | Watch obligors | Domestic | Corporate | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		28,881	16,716
Financing Receivables Not Impaired | Watch obligors | Domestic | Corporate | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[2]	7,725	2,708
Financing Receivables Not Impaired | Watch obligors | Domestic | Corporate | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		21,127	23,491
Financing Receivables Not Impaired | Watch obligors | Domestic | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[6]	145,546	165,244
Financing Receivables Not Impaired | Watch obligors | Domestic | Retail | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[6]	8,278	9,775
Financing Receivables Not Impaired | Watch obligors | Domestic | Retail | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[6]	14,490	15,466
Financing Receivables Not Impaired | Watch obligors | Domestic | Retail | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[6]	18,586	21,109
Financing Receivables Not Impaired | Watch obligors | Domestic | Retail | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[6]	25,553	27,975
Financing Receivables Not Impaired | Watch obligors | Domestic | Retail | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[6]	7,472	8,916
Financing Receivables Not Impaired | Watch obligors | Domestic | Retail | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[6]	319	194
Financing Receivables Not Impaired | Watch obligors | Domestic | Retail | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[2],[4],[6]	421	259
Financing Receivables Not Impaired | Watch obligors | Domestic | Retail | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[6]	70,427	81,550
Financing Receivables Not Impaired | Watch obligors | Domestic | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5],[6]	6,721	123,087
Financing Receivables Not Impaired | Watch obligors | Domestic | Other | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5],[6]	1,303	246
Financing Receivables Not Impaired | Watch obligors | Domestic | Other | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5],[6]	25
Financing Receivables Not Impaired | Watch obligors | Domestic | Other | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5],[6]	1	55
Financing Receivables Not Impaired | Watch obligors | Domestic | Other | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5],[6]	591	476
Financing Receivables Not Impaired | Watch obligors | Domestic | Other | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[2],[5],[6]	3,633	121,201
Financing Receivables Not Impaired | Watch obligors | Domestic | Other | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5],[6]	1,168	1,109
Financing Receivables Not Impaired | Watch obligors | Foreign | Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		357,851	426,599
Financing Receivables Not Impaired | Watch obligors | Foreign | Corporate | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		10,458	28,126
Financing Receivables Not Impaired | Watch obligors | Foreign | Corporate | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		347,060	398,231
Financing Receivables Not Impaired | Watch obligors | Foreign | Corporate | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		333	242
Financing Receivables Not Impaired | Watch obligors | Foreign | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[6]		6
Financing Receivables Not Impaired | Watch obligors | Foreign | Retail | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[6]		6
Financing Receivables Not Impaired | Watch obligors | Foreign | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5],[6]	39,283	66,297
Financing Receivables Not Impaired | Watch obligors | Foreign | Other | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5],[6]	38,404	64,950
Financing Receivables Not Impaired | Watch obligors | Foreign | Other | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5],[6]	879	1,347
Financing Receivables Impaired | Impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		646,132	615,260
Financing Receivables Impaired | Impaired loans | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		494,644	505,631
Financing Receivables Impaired | Impaired loans | Domestic | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		108,644	142,070
Financing Receivables Impaired | Impaired loans | Domestic | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		46,185	40,833
Financing Receivables Impaired | Impaired loans | Domestic | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		73,573	58,075
Financing Receivables Impaired | Impaired loans | Domestic | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		134,614	130,884
Financing Receivables Impaired | Impaired loans | Domestic | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		31,206	27,527
Financing Receivables Impaired | Impaired loans | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		10,300	12,341
Financing Receivables Impaired | Impaired loans | Domestic | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[2]	8,954	3,739
Financing Receivables Impaired | Impaired loans | Domestic | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		81,168	90,162
Financing Receivables Impaired | Impaired loans | Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		151,488	109,629
Financing Receivables Impaired | Impaired loans | Foreign | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		2	1,819
Financing Receivables Impaired | Impaired loans | Foreign | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		150,410	106,650
Financing Receivables Impaired | Impaired loans | Foreign | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		¥ 1,076	¥ 1,160
[1]	Amounts represent loan balances before deducting unearned income and deferred loan fees.
[2]	Other industries of Domestic includes trade receivables and lease receivables of consolidated VIEs.
[3]	The majority of Total foreign consist of Commercial and Industrial loans.
[4]	The obligor category classification is mainly based on past due status.
[5]	Non-impaired loans held by subsidiaries other than MHBK and MHTB constitute Other, since their portfolio segments are not identical to those of MHBK and MHTB.
[6]	Special attention obligors are watch obligors with debt in TDR or 90 days or more delinquent debt. Loans to such obligors are considered impaired.

Loans (Impaired Loans Informati

Loans (Impaired Loans Information) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	¥ 529,048	¥ 478,527
Recorded investment not requiring an allowance for loan losses	[1],[2]	117,084	136,733
Total		646,132	615,260
Unpaid principal balance		694,995	664,870
Related allowance	[3]	169,245	152,513
Average recorded investment		609,745	756,205
Interest income recognized	[4]	8,157	8,091
Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	409,969	415,181
Recorded investment not requiring an allowance for loan losses	[1],[2]	84,675	90,450
Total		494,644	505,631
Unpaid principal balance		530,011	539,541
Related allowance	[3]	121,900	124,180
Average recorded investment		496,186	604,617
Interest income recognized	[4]	6,639	7,049
Domestic | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	103,039	135,083
Recorded investment not requiring an allowance for loan losses	[1],[2]	5,605	6,987
Total		108,644	142,070
Unpaid principal balance		111,533	146,857
Related allowance	[3]	39,301	45,750
Average recorded investment		122,764	218,899
Interest income recognized	[4]	1,404	1,869
Domestic | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	36,873	31,557
Recorded investment not requiring an allowance for loan losses	[1],[2]	9,312	9,276
Total		46,185	40,833
Unpaid principal balance		51,158	48,752
Related allowance	[3]	4,661	4,411
Average recorded investment		42,224	49,926
Interest income recognized	[4]	487	516
Domestic | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	64,021	48,691
Recorded investment not requiring an allowance for loan losses	[1],[2]	9,552	9,384
Total		73,573	58,075
Unpaid principal balance		79,736	64,348
Related allowance	[3]	16,311	13,305
Average recorded investment		67,679	60,198
Interest income recognized	[4]	1,058	919
Domestic | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	124,911	119,463
Recorded investment not requiring an allowance for loan losses	[1],[2]	9,703	11,421
Total		134,614	130,884
Unpaid principal balance		147,665	139,556
Related allowance	[3]	38,763	42,798
Average recorded investment		130,860	139,333
Interest income recognized	[4]	1,814	1,842
Domestic | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	28,297	25,019
Recorded investment not requiring an allowance for loan losses	[1],[2]	2,909	2,508
Total		31,206	27,527
Unpaid principal balance		32,139	28,480
Related allowance	[3]	13,146	6,862
Average recorded investment		29,864	25,672
Interest income recognized	[4]	412	370
Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	6,473	8,392
Recorded investment not requiring an allowance for loan losses	[1],[2]	3,827	3,949
Total		10,300	12,341
Unpaid principal balance		10,300	12,341
Related allowance	[3]	1,327	3,176
Average recorded investment		10,671	8,648
Interest income recognized	[4]	109	78
Domestic | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	8,867	3,650
Recorded investment not requiring an allowance for loan losses	[1],[2]	87	89
Total		8,954	3,739
Unpaid principal balance		9,149	3,869
Related allowance	[3]	5,761	3,563
Average recorded investment		6,042	4,537
Interest income recognized	[4]	29	53
Domestic | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	37,488	43,326
Recorded investment not requiring an allowance for loan losses	[1],[2]	43,680	46,836
Total		81,168	90,162
Unpaid principal balance		88,331	95,338
Related allowance	[3]	2,630	4,315
Average recorded investment		86,082	97,404
Interest income recognized	[4]	1,326	1,402
Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1],[5]	119,079	63,346
Recorded investment not requiring an allowance for loan losses	[1],[2],[5]	32,409	46,283
Total	[5]	151,488	109,629
Unpaid principal balance	[5]	164,984	125,329
Related allowance	[3],[5]	47,345	28,333
Average recorded investment	[5]	113,559	151,588
Interest income recognized	[4],[5]	¥ 1,518	¥ 1,042
[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 impaired loans.
[2]	These impaired loans do not require an allowance for loan losses because the MHFG Group has sufficient collateral to cover probable loan losses.
[3]	The allowance for loan losses on impaired loans includes the allowance for groups of loans which were collectively evaluated for impairment, in addition to the allowance for those loans that were individually evaluated for impairment. The total carrying amount of the groups of loans which were collectively evaluated for impairment at March 31, 2018 and 2019 was ¥245,809 million and ¥257,099 million, respectively.
[4]	Amounts represent the amount of interest income on impaired loans recognized on a cash basis and included in Interest income on loans in the consolidated statements of income.
[5]	The majority of Total foreign consist of Commercial and Industrial loans.

Loans (Impaired Loans Informa_2

Loans (Impaired Loans Information) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2019	Mar. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment	¥ 646,132	¥ 615,260
Small balance homogeneous loans of which were collectively evaluated for impairment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment	¥ 257,099	¥ 245,809

Loans (Troubled Debt Restructur

Loans (Troubled Debt Restructurings Entered Modified Periods by Type of Concession Granted) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019		Mar. 31, 2018
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	[1]	¥ 984
Loan forgiveness or debt to equity swaps charge-off		1,964
Interest rate reduction and/or postponement of principal and/or interest		566,325		¥ 408,427
Domestic
Financing Receivable, Modifications [Line Items]
Interest rate reduction and/or postponement of principal and/or interest		522,292	[2]	364,417
Domestic | Manufacturing
Financing Receivable, Modifications [Line Items]
Interest rate reduction and/or postponement of principal and/or interest		134,544		110,624
Domestic | Construction and real estate
Financing Receivable, Modifications [Line Items]
Interest rate reduction and/or postponement of principal and/or interest		39,254		13,430
Domestic | Services
Financing Receivable, Modifications [Line Items]
Interest rate reduction and/or postponement of principal and/or interest		87,468		40,774
Domestic | Wholesale and retail
Financing Receivable, Modifications [Line Items]
Interest rate reduction and/or postponement of principal and/or interest		167,299		148,560
Domestic | Transportation and communications
Financing Receivable, Modifications [Line Items]
Interest rate reduction and/or postponement of principal and/or interest		33,991		27,294
Domestic | Banks and other financial institutions
Financing Receivable, Modifications [Line Items]
Interest rate reduction and/or postponement of principal and/or interest		17,286		8,529
Domestic | Other industries
Financing Receivable, Modifications [Line Items]
Interest rate reduction and/or postponement of principal and/or interest		120		246
Domestic | Individuals
Financing Receivable, Modifications [Line Items]
Interest rate reduction and/or postponement of principal and/or interest		42,330		14,960
Foreign
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	[1]	984
Loan forgiveness or debt to equity swaps charge-off		1,964
Interest rate reduction and/or postponement of principal and/or interest		¥ 44,033		¥ 44,010	[2]
[1]	Amounts represent the book values of loans immediately after the restructurings.
[2]	The majority of Total foreign consist of Commercial and Industrial loans.

Loans (Payment Defaults Occurre

Loans (Payment Defaults Occurred During Periods with Respect to Loans Modified as Troubled Debt Restructurings within Previous Six Months) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Financing Receivable, Modifications [Line Items]
Recorded investment	¥ 27,880	¥ 41,079
Domestic
Financing Receivable, Modifications [Line Items]
Recorded investment	22,462	36,491
Domestic | Manufacturing
Financing Receivable, Modifications [Line Items]
Recorded investment	1,173	4,019
Domestic | Construction and real estate
Financing Receivable, Modifications [Line Items]
Recorded investment	121	80
Domestic | Services
Financing Receivable, Modifications [Line Items]
Recorded investment	1,335	4,469
Domestic | Wholesale and retail
Financing Receivable, Modifications [Line Items]
Recorded investment	15,087	25,710
Domestic | Transportation and communications
Financing Receivable, Modifications [Line Items]
Recorded investment	878	264
Domestic | Banks and other financial institutions
Financing Receivable, Modifications [Line Items]
Recorded investment	66
Domestic | Other industries
Financing Receivable, Modifications [Line Items]
Recorded investment	1,650	130
Domestic | Individuals
Financing Receivable, Modifications [Line Items]
Recorded investment	2,152	1,819
Foreign
Financing Receivable, Modifications [Line Items]
Recorded investment	¥ 5,418	¥ 4,588

Loans (Age Analysis of Past Due

Loans (Age Analysis of Past Due Loans) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		¥ 155,737	¥ 179,741
Current		82,796,353	83,481,599
Total	[1]	82,952,090	83,661,340
Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		128,542	137,078
Current		54,280,602	58,523,436
Total		54,409,144	58,660,514
Domestic | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		9,759	9,092
Current		9,548,387	8,147,249
Total		9,558,146	8,156,341
Domestic | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		33,156	30,748
Current		8,921,667	8,070,920
Total		8,954,823	8,101,668
Domestic | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		4,323	8,170
Current		5,109,063	5,015,848
Total		5,113,386	5,024,018
Domestic | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		10,897	9,426
Current		5,152,370	5,103,247
Total		5,163,267	5,112,673
Domestic | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		2,738	2,823
Current		3,619,392	3,562,046
Total		3,622,130	3,564,869
Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		493	1,301
Current		4,302,738	4,470,122
Total		4,303,231	4,471,423
Domestic | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current		2,358,904	8,882,125
Total		2,358,904	8,882,125
Domestic | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		59	82
Current		5,477,393	5,018,305
Total	[2]	5,477,452	5,018,387
Domestic | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		67,117	75,436
Current		9,790,688	10,253,574
Total		9,857,805	10,329,010
Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due	[3]	27,195	42,663
Current	[3]	28,515,751	24,958,163
Total	[3]	28,542,946	25,000,826
Foreign | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		9,126,392	7,465,140
Foreign | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		296,872	302,891
30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		33,642	38,759
30-59 Days Past Due | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		32,974	37,862
30-59 Days Past Due | Domestic | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		2,210	585
30-59 Days Past Due | Domestic | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		1,010	1,641
30-59 Days Past Due | Domestic | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		633	1,977
30-59 Days Past Due | Domestic | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		1,614	1,704
30-59 Days Past Due | Domestic | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		363	356
30-59 Days Past Due | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		3
30-59 Days Past Due | Domestic | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		2	33
30-59 Days Past Due | Domestic | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		27,139	31,566
30-59 Days Past Due | Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due	[3]	668	897
60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		15,142	17,997
60-89 Days Past Due | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		14,931	17,547
60-89 Days Past Due | Domestic | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		513	470
60-89 Days Past Due | Domestic | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		1,054	474
60-89 Days Past Due | Domestic | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		196	1,142
60-89 Days Past Due | Domestic | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		1,415	1,083
60-89 Days Past Due | Domestic | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		256	639
60-89 Days Past Due | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		484	1,301
60-89 Days Past Due | Domestic | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due			12
60-89 Days Past Due | Domestic | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		11,013	12,426
60-89 Days Past Due | Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due	[3]	211	450
90 Days or More Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		106,953	122,985
90 Days or More Past Due | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		80,637	81,669
90 Days or More Past Due | Domestic | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		7,036	8,037
90 Days or More Past Due | Domestic | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		31,092	28,633
90 Days or More Past Due | Domestic | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		3,494	5,051
90 Days or More Past Due | Domestic | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		7,868	6,639
90 Days or More Past Due | Domestic | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		2,119	1,828
90 Days or More Past Due | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		6
90 Days or More Past Due | Domestic | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		57	37
90 Days or More Past Due | Domestic | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		28,965	31,444
90 Days or More Past Due | Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due	[3]	¥ 26,316	¥ 41,316
[1]	Amounts represent loan balances before deducting unearned income and deferred loan fees.
[2]	Other industries of Domestic includes trade receivables and lease receivables of consolidated VIEs.
[3]	The majority of Total foreign consist of Commercial and Industrial loans.

Allowance for Loan Losses (Chan

Allowance for Loan Losses (Changes in Allowance for Loan Losses, Allowance for Loan Losses and Loans Outstanding Disaggregated on Basis of Impairment Method, by Portfolio Segment) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of fiscal year		¥ 309,902	¥ 479,673	¥ 451,247
Provision (credit) for loan losses		32,459	(126,362)	37,668
Charge-offs		(47,524)	(55,862)	(31,252)
Recoveries		14,103	15,220	25,600
Net charge-offs		(33,421)	(40,642)	(5,652)
Others	[1]	(1,739)	(2,767)	(3,590)
Balance at end of fiscal year		307,201	309,902	479,673
Allowance for loan losses of which individually evaluated for impairment		150,527	139,774
Allowance for loan losses of which collectively evaluated for impairment		156,674	170,128
Loans	[2]	82,952,090	83,661,340
Loans of which individually evaluated for impairment	[2]	615,098	675,440
Loans of which collectively evaluated for impairment	[2]	82,336,992	82,985,900
Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of fiscal year		249,072	407,327	367,739
Provision (credit) for loan losses		31,693	(123,470)	45,059
Charge-offs		(39,728)	(44,621)	(22,901)
Recoveries		11,019	12,924	18,320
Net charge-offs		(28,709)	(31,697)	(4,581)
Others	[1]	847	(3,088)	(890)
Balance at end of fiscal year		252,903	249,072	407,327
Allowance for loan losses of which individually evaluated for impairment		139,472	129,789
Allowance for loan losses of which collectively evaluated for impairment		113,431	119,283
Loans	[2]	66,804,088	60,837,559
Loans of which individually evaluated for impairment	[2]	539,893	593,053
Loans of which collectively evaluated for impairment	[2]	66,264,195	60,244,506
Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of fiscal year		28,192	36,923	44,221
Provision (credit) for loan losses		(2,658)	(7,427)	(10,666)
Charge-offs		(2,856)	(2,118)	(1,754)
Recoveries		552	814	5,122
Net charge-offs		(2,304)	(1,304)	3,368
Balance at end of fiscal year		23,230	28,192	36,923
Allowance for loan losses of which individually evaluated for impairment		2,122	2,602
Allowance for loan losses of which collectively evaluated for impairment		21,108	25,590
Loans	[2]	10,596,994	11,133,862
Loans of which individually evaluated for impairment	[2]	20,886	21,364
Loans of which collectively evaluated for impairment	[2]	10,576,108	11,112,498
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of fiscal year		32,638	35,423	39,287
Provision (credit) for loan losses		3,424	4,535	3,275
Charge-offs		(4,940)	(9,123)	(6,597)
Recoveries		2,532	1,482	2,158
Net charge-offs		(2,408)	(7,641)	(4,439)
Others	[1]	(2,586)	321	(2,700)
Balance at end of fiscal year		31,068	32,638	¥ 35,423
Allowance for loan losses of which individually evaluated for impairment		8,933	7,383
Allowance for loan losses of which collectively evaluated for impairment		22,135	25,255
Loans	[2]	5,551,008	11,689,919
Loans of which individually evaluated for impairment	[2]	54,319	61,023
Loans of which collectively evaluated for impairment	[2]	¥ 5,496,689	¥ 11,628,896
[1]	Others includes primarily foreign exchange translation.
[2]	Amounts represent loan balances before deducting unearned income and deferred loan fees.

Premises and Equipment (Summary

Premises and Equipment (Summary of Premises and Equipment) (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2019	Mar. 31, 2018
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	¥ 3,363,162	¥ 3,448,754
Less: Accumulated depreciation and amortization	1,462,210	1,332,570
Premises and equipment-net	1,900,952	2,116,184
Land
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	563,032	566,040
Buildings
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	826,781	811,911
Equipment and furniture
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	472,186	484,102
Leasehold improvements
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	97,508	97,066
Construction in Progress
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	37,174	25,849
Software and Software Development Costs
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	¥ 1,366,481	¥ 1,463,786

Premises and Equipment - Additi

Premises and Equipment - Additional Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Property, Plant and Equipment [Line Items]
Depreciation and amortization	¥ 345,560	¥ 169,346	¥ 163,769
Impairment losses	27,428
Premises and equipment under capital leases
Property, Plant and Equipment [Line Items]
Premises and equipment under capital leases	83,935	83,734
Premises and equipment under capital leases, accumulated depreciation and amortization	57,193	¥ 42,158
Retail And Business Banking Company
Property, Plant and Equipment [Line Items]
Impairment losses	15,761
General and Administrative expenses
Property, Plant and Equipment [Line Items]
Impairment losses	8,910
Occupancy expenses
Property, Plant and Equipment [Line Items]
Impairment losses	¥ 18,518

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets (Changes in Goodwill) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Goodwill [Line Items]
Balance at beginning of fiscal year		¥ 95,184	¥ 95,176	¥ 19,097
Goodwill acquired	[1]			76,225
Foreign exchange translation		(33)	8	(146)
Balance at end of fiscal year		95,151	95,184	95,176
Gross amount of goodwill	[2]	169,489	170,926	171,432
Accumulated impairment losses		¥ 74,338	¥ 75,742	¥ 76,256
[1]	Goodwill acquired is entirely related to the acquisition of Asset Management One (see Note 3 "Business combination").
[2]	Goodwill is recorded at a designated reporting unit level for the purpose of assessing impairment. Goodwill is not allocated to the reportable segments in Note 32 "Business segment information".

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets (Gross Carrying Amount, Accumulated Amortization and Net Carrying Amount of Intangible Assets) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018
Intangible Assets by Major Class [Line Items]
Gross carrying amount		¥ 128,580	¥ 128,826
Gross carrying amount		8,702	9,199
Net carrying amount		8,702	9,199
Gross carrying amount		137,282	138,025
Accumulated amortization		63,042	53,578
Net carrying amount		65,538	75,248
Net carrying amount		74,240	84,447
Customer relationships
Intangible Assets by Major Class [Line Items]
Gross carrying amount	[1]	126,882	126,979
Accumulated amortization	[1]	61,630	52,237
Net carrying amount	[1]	65,252	74,742
Other
Intangible Assets by Major Class [Line Items]
Gross carrying amount		1,698	1,847
Accumulated amortization		1,412	1,341
Net carrying amount		¥ 286	¥ 506
[1]	Customer relationships were acquired in connection with the merger of MHSC and Shinko on May 7, 2009 and the integration among asset management companies on October 1, 2016, see Note 3 "Business combination" for further details of the integration among asset management companies. See Note 1 "Basis of presentation and summary of significant accounting policies" for further information.

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Additional Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Goodwill and Intangible Assets Disclosure [Line Items]
Intangible assets amortization expense recognized	¥ 9,604	¥ 9,812	¥ 7,433

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets (Estimated Aggregate Amortization Expense in Respect of Intangible Assets) (Detail) ¥ in Millions	Mar. 31, 2019JPY (¥)
Finite-Lived Intangible Assets [Line Items]
2020	¥ 8,969
2021	8,237
2022	7,702
2023	7,184
2024	¥ 6,666

Pledged Assets and Collateral_2

Pledged Assets and Collateral (Amounts Pledged as Collateral for Borrowings and for Other Purposes) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2019	Mar. 31, 2018
Financial Instruments Owned and Pledged as Collateral [Line Items]
Interest-bearing deposits in other banks	¥ 68	¥ 37
Trading account assets	4,137	5,611
Investments	6,076	6,500
Loans	4,055	5,229
Other assets	1,886	2,099
Total	¥ 16,222	¥ 19,476

Pledged Assets and Collateral_3

Pledged Assets and Collateral (Associated Liabilities Collateralized by Pledged Assets) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2019	Mar. 31, 2018
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Deposits	¥ 386	¥ 256
Payables under repurchase agreements	3,435	5,518
Payables under securities lending transactions	1,675	1,193
Other short-term borrowings	519	441
Long-term debt	1,431	3,179
Total	¥ 7,446	¥ 10,587

Pledged Assets and Collateral -

Pledged Assets and Collateral - Additional Information (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2019	Mar. 31, 2018
Assets that Continue to be Recognized, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]
Reserve funds maintained with the BOJ	¥ 43,552	¥ 45,325
Reserve funds requires to be maintained by MHFG Group	1,583	1,589
Fair value collateral received that can be sold or repledged	16,114	13,419
Fair value collateral received that can be sold or repledged, value of collateral sold or repledged	¥ 12,264	¥ 12,655

Deposits (Balances of Time Depo

Deposits (Balances of Time Deposits and Certificates of Deposit Issued by Domestic Offices in Amounts of JPY10 Million or More and by Foreign Offices in Amounts of USD100,000 or More) (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2019	Mar. 31, 2018
Domestic
Deposits From Banking Clients [Line Items]
Domestic deposit in amounts of YEN 10 million or more	¥ 22,221,945	¥ 22,973,137
Foreign
Deposits From Banking Clients [Line Items]
Domestic deposit in amounts of YEN 10 million or more	25,301,760	19,030,714
Time deposits | Domestic
Deposits From Banking Clients [Line Items]
Domestic deposit in amounts of YEN 10 million or more	16,578,642	17,194,707
Time deposits | Foreign
Deposits From Banking Clients [Line Items]
Domestic deposit in amounts of YEN 10 million or more	17,606,520	13,426,554
Certificates of deposit | Domestic
Deposits From Banking Clients [Line Items]
Domestic deposit in amounts of YEN 10 million or more	5,643,303	5,778,430
Certificates of deposit | Foreign
Deposits From Banking Clients [Line Items]
Domestic deposit in amounts of YEN 10 million or more	¥ 7,695,240	¥ 5,604,160

Deposits - Additional Informati

Deposits - Additional Information (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2019	Mar. 31, 2018
Deposits From Banking Clients [Line Items]
Aggregate amount of demand deposits in overdraft status that have been reclassified as loan balances	¥ 810	¥ 792

Deposits (Balance and Remaining

Deposits (Balance and Remaining Maturities of Time Deposits and Certificates of Deposit Issued by Domestic and Foreign Offices) (Detail) ¥ in Millions	Mar. 31, 2019JPY (¥)
Deposits From Banking Clients [Line Items]
Total	¥ 56,231,599
Bank Time Deposits Liabilities Domestic
Deposits From Banking Clients [Line Items]
Due in one year or less	21,240,581
Due after one year through two years	1,709,682
Due after two years through three years	1,387,191
Due after three years through four years	319,829
Due after four years through five years	371,921
Due after five years	245,455
Total	25,274,659
Certificates Of Deposit Liabilities Domestic
Deposits From Banking Clients [Line Items]
Due in one year or less	5,492,603
Due after one year through two years	150,700
Total	5,643,303
Bank Time Deposits Liabilities Foreign
Deposits From Banking Clients [Line Items]
Due in one year or less	17,525,778
Due after one year through two years	65,423
Due after two years through three years	3,902
Due after three years through four years	775
Due after four years through five years	11,369
Due after five years	11,122
Total	17,618,369
Certificates Of Deposit Liabilities Foreign
Deposits From Banking Clients [Line Items]
Due in one year or less	7,468,492
Due after one year through two years	162,721
Due after two years through three years	64,055
Total	7,695,268
Time deposits
Deposits From Banking Clients [Line Items]
Total	42,893,028
Certificates of deposit
Deposits From Banking Clients [Line Items]
Total	13,338,571
Domestic
Deposits From Banking Clients [Line Items]
Due in one year or less	26,733,184
Due after one year through two years	1,860,382
Due after two years through three years	1,387,191
Due after three years through four years	319,829
Due after four years through five years	371,921
Due after five years	245,455
Total	30,917,962
Foreign
Deposits From Banking Clients [Line Items]
Due in one year or less	24,994,270
Due after one year through two years	228,144
Due after two years through three years	67,957
Due after three years through four years	775
Due after four years through five years	11,369
Due after five years	11,122
Total	¥ 25,313,637

Short-Term Borrowings and Lon_3

Short-Term Borrowings and Long-Term Debt (Details of Other Short-Term Borrowings) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018
Short-term Debt [Line Items]
Borrowings from the Bank of Japan		¥ 508,627	¥ 432,328
Other		189,478	183,114
Total		1,994,826	1,688,018
Mizuho Financial Group Inc
Short-term Debt [Line Items]
Commercial paper and short-term notes issued	[1],[2]	1,274,382	1,044,591
Consolidated VIEs
Short-term Debt [Line Items]
Commercial paper and short-term notes issued	[1]	22,339	27,985
Total		¥ 23,495	¥ 31,392
[1]	Short-term notes are issued under the laws of Japan in the form of commercial paper.
[2]	The amounts of commercial paper and short-term notes issued by MHFG's subsidiaries were ¥710,391 million and ¥334,200 million, respectively, at March 31, 2018, and ¥941,182 million and ¥333,200 million, respectively, at March 31, 2019.

Short-Term Borrowings and Lon_4

Short-Term Borrowings and Long-Term Debt (Details of Other Short-Term Borrowings) (Parenthetical) (Detail) - Mizuho Financial Group Inc - JPY (¥) ¥ in Millions	Mar. 31, 2019	Mar. 31, 2018
Short-term Debt [Line Items]
Commercial paper	¥ 941,182	¥ 710,391
Short-term notes	¥ 333,200	¥ 334,200

Short-Term Borrowings and Lon_5

Short-Term Borrowings and Long-Term Debt (Long-Term Debt with Original Maturities of More than One Year) (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2019	Mar. 31, 2018
Debt Instrument [Line Items]
Obligations under capital leases	¥ 25,020	¥ 36,010
Loan participation borrowings	142,838	89,353
Senior borrowings and bonds	7,503,032	9,184,075
Subordinated borrowings and bonds	3,858,510	3,645,792
Total	¥ 11,529,400	¥ 12,955,230

Short-Term Borrowings and Lon_6

Short-Term Borrowings and Long-Term Debt (Interest Rates and Maturities of Senior Borrowings and Bonds, and Subordinated Borrowings and Bonds) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Debt Instrument [Line Items]
Borrowings and bonds		¥ 11,361,542	¥ 12,829,867
Senior borrowings and bonds
Debt Instrument [Line Items]
Borrowings and bonds		7,503,032	9,184,075
Senior borrowings and bonds | Fixed Rate | Denominated in Japanese yen
Debt Instrument [Line Items]
Borrowings and bonds		2,057,156	4,146,989
Senior borrowings and bonds | Fixed Rate | Denominated in U.S. dollars
Debt Instrument [Line Items]
Borrowings and bonds		2,765,247	2,519,845
Senior borrowings and bonds | Fixed Rate | Denominated in other currencies
Debt Instrument [Line Items]
Borrowings and bonds		324,162	233,842
Senior borrowings and bonds | Floating Rate | Denominated in Japanese yen
Debt Instrument [Line Items]
Borrowings and bonds		656,029	662,751
Senior borrowings and bonds | Floating Rate | Denominated in U.S. dollars
Debt Instrument [Line Items]
Borrowings and bonds		1,493,617	1,469,248
Senior borrowings and bonds | Floating Rate | Denominated in other currencies
Debt Instrument [Line Items]
Borrowings and bonds		206,821	151,400
Subordinated borrowings and bonds
Debt Instrument [Line Items]
Borrowings and bonds		3,858,510	3,645,792
Subordinated borrowings and bonds | Fixed Rate | Denominated in Japanese yen
Debt Instrument [Line Items]
Borrowings and bonds		3,442,438	3,247,639
Subordinated borrowings and bonds | Fixed Rate | Denominated in U.S. dollars
Debt Instrument [Line Items]
Borrowings and bonds		¥ 416,072	¥ 398,153
Minimum | Senior borrowings and bonds | Fixed Rate | Denominated in Japanese yen
Debt Instrument [Line Items]
Interest rates	[1]	0.00%
Maturities, Start	[2]	2019-04
Minimum | Senior borrowings and bonds | Fixed Rate | Denominated in U.S. dollars
Debt Instrument [Line Items]
Interest rates	[1]	0.00%
Maturities, Start	[2]	2019-04
Minimum | Senior borrowings and bonds | Fixed Rate | Denominated in other currencies
Debt Instrument [Line Items]
Interest rates	[1]	0.02%
Maturities, Start	[2]	2019-04
Minimum | Senior borrowings and bonds | Floating Rate | Denominated in Japanese yen
Debt Instrument [Line Items]
Interest rates	[1]	0.00%
Maturities, Start	[2]	2019-04
Minimum | Senior borrowings and bonds | Floating Rate | Denominated in U.S. dollars
Debt Instrument [Line Items]
Interest rates	[1]	0.00%
Maturities, Start	[2]	2019-04
Minimum | Senior borrowings and bonds | Floating Rate | Denominated in other currencies
Debt Instrument [Line Items]
Interest rates	[1]	0.00%
Maturities, Start	[2]	2019-04
Minimum | Subordinated borrowings and bonds | Fixed Rate | Denominated in Japanese yen
Debt Instrument [Line Items]
Interest rates	[1]	0.40%
Maturities, Start	[2]	2019-06
Minimum | Subordinated borrowings and bonds | Fixed Rate | Denominated in U.S. dollars
Debt Instrument [Line Items]
Interest rates	[1]	4.30%
Maturities, Start	[2]	2022-07
Maximum | Senior borrowings and bonds | Fixed Rate | Denominated in Japanese yen
Debt Instrument [Line Items]
Interest rates	[1]	8.10%
Maturities, End	[2]	2046-12
Maximum | Senior borrowings and bonds | Fixed Rate | Denominated in U.S. dollars
Debt Instrument [Line Items]
Interest rates	[1]	5.39%
Maturities, End	[2]	2048-03
Maximum | Senior borrowings and bonds | Fixed Rate | Denominated in other currencies
Debt Instrument [Line Items]
Interest rates	[1]	12.40%
Maturities, End	[2]	2037-05
Maximum | Senior borrowings and bonds | Floating Rate | Denominated in Japanese yen
Debt Instrument [Line Items]
Interest rates	[1]	25.00%
Maturities, End	[2]	2049-03
Maximum | Senior borrowings and bonds | Floating Rate | Denominated in U.S. dollars
Debt Instrument [Line Items]
Interest rates	[1]	16.00%
Maturities, End	[2]	2033-07
Maximum | Senior borrowings and bonds | Floating Rate | Denominated in other currencies
Debt Instrument [Line Items]
Interest rates	[1]	9.00%
Maturities, End	[2]	2024-03
Maximum | Subordinated borrowings and bonds | Fixed Rate | Denominated in Japanese yen
Debt Instrument [Line Items]
Interest rates	[1]	4.26%
Maximum | Subordinated borrowings and bonds | Fixed Rate | Denominated in U.S. dollars
Debt Instrument [Line Items]
Interest rates	[1]	4.70%
Maturities, End	[2]	2025-10
[1]	The interest rates disclosed reflect the range of contractual rates in effect at March 31, 2019.
[2]	Maturity information disclosed is the range of maturities at March 31, 2019.

Short-Term Borrowings and Lon_7

Short-Term Borrowings and Long-Term Debt (Contractual Maturities of Long-Term Debt) (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2019	Mar. 31, 2018
Debt Instrument [Line Items]
2020	¥ 1,401,583
2021	1,443,458
2022	1,319,030
2023	1,176,818
2024	508,821
2025 and thereafter	5,679,690
Total	¥ 11,529,400	¥ 12,955,230

Other Assets and Liabilities (D

Other Assets and Liabilities (Details of Other Assets and Liabilities) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018
Other assets:
Receivables from brokers, dealers and customers for securities transactions	[1]	¥ 1,517,235	¥ 1,578,952
Other		400,676	368,030
Collateral pledged for derivative transactions		856,439	981,390
Margins provided for futures contracts		159,747	142,156
Other		857,814	965,137
Prepaid pension cost		850,472	874,191
Security deposits		123,317	126,001
Loans held for sale		24,921	86,153
Other		485,383	609,624
Total		5,276,004	5,731,634
Other liabilities:
Payables to brokers, dealers and customers for securities transactions	[1]	2,572,315	1,410,785
Other		442,776	455,789
Guaranteed trust principal	[2]	809,450	761,685
Collateral accepted for derivative transactions		589,411	598,524
Margins accepted for futures contracts		339,863	325,038
Unearned income	[3]	126,594	130,916
Other		1,052,297	1,022,858
Total		¥ 5,932,706	¥ 4,705,595
[1]	Receivables from brokers, dealers and customers for securities transactions included ¥372,395 million and ¥555,938 million of such receivables of consolidated VIEs at March 31, 2018 and 2019, respectively. Payables to brokers, dealers and customers for securities transactions included ¥422,060 million and ¥620,766 million of such payables of consolidated VIEs at March 31, 2018 and 2019, respectively.
[2]	Guaranteed trust principal is the 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 25 "Variable interest entities and securitizations" for further discussion of the guaranteed principal money trusts.
[3]	Unearned income is primarily comprised of loan fees received from consumer loan customers when loans are made. This income is being deferred and recognized in earnings over the life of the loan.

Other Assets and Liabilities _2

Other Assets and Liabilities (Details of Other Assets and Liabilities) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018
Other Assets and Other Liabilities [Line Items]
Accounts receivable from brokers, dealers and customers for securities transactions	[1]	¥ 1,517,235	¥ 1,578,952
Accounts payable to brokers, dealers and customers for securities transactions	[1]	2,572,315	1,410,785
Consolidated VIEs
Other Assets and Other Liabilities [Line Items]
Accounts receivable from brokers, dealers and customers for securities transactions		555,938	372,395
Accounts payable to brokers, dealers and customers for securities transactions		¥ 620,766	¥ 422,060
[1]	Receivables from brokers, dealers and customers for securities transactions included ¥372,395 million and ¥555,938 million of such receivables of consolidated VIEs at March 31, 2018 and 2019, respectively. Payables to brokers, dealers and customers for securities transactions included ¥422,060 million and ¥620,766 million of such payables of consolidated VIEs at March 31, 2018 and 2019, respectively.

Preferred Stock (Composition of

Preferred Stock (Composition of Preferred Stock) (Detail) - shares	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017	Apr. 01, 2016
Class of Stock [Line Items]
Number of shares Issued				914,752,000
Class XI preferred stock
Class of Stock [Line Items]
Number of shares Authorized			914,752,000
Number of shares Issued	0	0	0
Class Fourteen Preferred Stock
Class of Stock [Line Items]
Number of shares Authorized	900,000,000	900,000,000	900,000,000
Number of shares Issued	0	0	0
Class Fifteen Preferred Stock
Class of Stock [Line Items]
Number of shares Authorized	900,000,000	900,000,000	900,000,000
Number of shares Issued	0	0	0
Class Sixteen Preferred Stock
Class of Stock [Line Items]
Number of shares Authorized	1,500,000,000	1,500,000,000	1,500,000,000
Number of shares Issued	0	0	0

Preferred Stock - Summary of Ch

Preferred Stock - Summary of Changes in Number of Issued Shares of Common Stock (Detail) ¥ in Millions	12 Months Ended
	Mar. 31, 2017JPY (¥)shares
Class of Stock [Line Items]
Balance at beginning of fiscal year | shares	914,752,000
Net change | shares	(914,752,000)	[1]
Balance at beginning of fiscal year | ¥	¥ 914,752
Net change | ¥	¥ (914,752)	[1]
[1]	In July 2016, all shares of the class XI preferred stock were converted into common stock and cancelled.

Common Stock - Summary of Chang

Common Stock - Summary of Changes in Number of Issued Shares of Common Stock (Detail) - shares	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Class of Stock [Line Items]
Balance at beginning of fiscal year	25,389,644,945	25,386,307,945	25,030,525,657
Issuance of new shares of common stock due to conversion of class XI preferred stockxx			349,677,288
Issuance of new shares of common stock due to exercise of stock acquisition rights	2,854,000	3,337,000	6,105,000
Balance at end of fiscal year	25,392,498,945	25,389,644,945	25,386,307,945

Dividends - Additional Informat

Dividends - Additional Information (Detail) ¥ in Millions	12 Months Ended
	Mar. 31, 2019JPY (¥)
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Capital stock	¥ 2,256,768
Capital surplus	1,196,673
Retained earnings	¥ 2,070,749
Description of dividend payment restrictions	Pursuant to the Companies Act, in making a distribution of retained earnings, an entity must set aside in its legal reserve an amount equal to one-tenth of the amount of retained earnings so distributed, until its legal reserve reaches one-quarter of its capital stock.
Percentage of retained earnings set aside for legal reserve	10.00%
Legal reserve	¥ 1,201,010
Maximum amount available for dividends under Company Law and the Banking Law	¥ 2,060,236
Minimum Common Equity Tier 1 ratio required for capital adequacy purposes	4.50%
Japan Gaap Additional Paid-in Capital
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Legal reserve	¥ 1,196,660
Japan Gaap Retained Earnings
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Legal reserve	¥ 4,350

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Changes in Each Component of AOCI) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019		Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of fiscal year		¥ 9,503,700		¥ 8,772,057
Less: reclassification adjustments for losses (gains) included in net income		(5,702)
Change during fiscal year		(42,945)		222,538	¥ 51,557
Balance at end of fiscal year		9,501,493		9,503,700	8,772,057
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of fiscal year		1,741,894		1,521,163	1,469,308
Cumulative effect of change in accounting principles		(1,535,142)	[1]		330
Balance at beginning of fiscal year, adjusted		206,752		1,521,163	1,469,638
Change during fiscal year		(42,731)		220,731	51,525
Balance at end of fiscal year		164,021		1,741,894	1,521,163
Net unrealized gains (losses) on available-for-sale securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of fiscal year		1,556,585		1,461,302	1,409,459
Cumulative effect of change in accounting principles		(1,525,064)	[1]		(85)
Balance at beginning of fiscal year, adjusted		31,521		1,461,302	1,409,374
Foreign currency translation adjustments during year		(11,358)		282,141	273,844
Less: reclassification adjustments for losses (gains) included in net income		1,856		(186,858)	(221,916)
Change during fiscal year		(9,502)		95,283	51,928
Balance at end of fiscal year		22,019		1,556,585	1,461,302
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of fiscal year		(35,076)		(5,535)	6,310
Cumulative effect of change in accounting principles					415
Balance at beginning of fiscal year, adjusted		(35,076)		(5,535)	6,725
Foreign currency translation adjustments during year		(22,737)		(26,936)	(11,920)
Less: reclassification adjustments for losses (gains) included in net income		(745)		(2,605)	(340)
Change during fiscal year		(23,482)		(29,541)	(12,260)
Balance at end of fiscal year		(58,558)		(35,076)	(5,535)
Pension liability adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of fiscal year		220,385		65,396	53,539
Foreign currency translation adjustments during year		(17,243)		157,737	11,561
Less: reclassification adjustments for losses (gains) included in net income		(6,696)		(2,748)	296
Change during fiscal year		(23,939)		154,989	11,857
Balance at end of fiscal year		196,446		¥ 220,385	¥ 65,396
Accumulated Own Credit Risk Adjustment Including Portion Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative effect of change in accounting principles	[1],[2]	(10,078)
Balance at beginning of fiscal year, adjusted	[2]	(10,078)
Foreign currency translation adjustments during year	[2]	14,293
Less: reclassification adjustments for losses (gains) included in net income	[2]	(101)
Change during fiscal year	[2]	14,192
Balance at end of fiscal year	[2]	¥ 4,114
[1]	See Note 2 "Recently issued accounting pronouncements" for further details of the cumulative-effect adjustment for AOCI.
[2]	The MHFG Group adopted ASU No.2016-01 on April 1, 2018. The ASU requires an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. See Note 2 "Recently issued accounting pronouncements" for further details.

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Income (Amounts Reclassified Out of Accumulated Other Comprehensive Income into Net Income) (Detail) ¥ in Millions	12 Months Ended
	Mar. 31, 2019JPY (¥)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Before tax	¥ 7,230	[1]
Tax effect	(1,528)	[2]
Net of tax before allocation to noncontrolling interests	5,702
Net of tax attributable to noncontrolling interests	(16)	[2]
Net of tax attributable to MHFG shareholders	5,686
Accumulated Net Unrealized Investment Gain (Loss) | Gain (Loss) on Investments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Before tax	(2,735)	[1]
Tax effect	889	[2]
Net of tax before allocation to noncontrolling interests	(1,846)
Net of tax attributable to noncontrolling interests	(10)	[2]
Net of tax attributable to MHFG shareholders	(1,856)
Accumulated Net Unrealized Investment Gain (Loss) | Foreign exchange adjustments gains (losses)-net
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Before tax	745	[1]
Net of tax before allocation to noncontrolling interests	745
Net of tax attributable to MHFG shareholders	745
Accumulated Defined Benefit Plans Adjustment | Salaries and employee benefits
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Before tax	9,068	[1]
Tax effect	(2,370)	[2]
Net of tax before allocation to noncontrolling interests	6,698
Net of tax attributable to noncontrolling interests	(2)	[2]
Net of tax attributable to MHFG shareholders	6,696
Accumulated Own Credit Risk Adjustment | Other Noninterest Income (Expenses)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Before tax	152	[1]
Tax effect	(47)	[2]
Net of tax before allocation to noncontrolling interests	105
Net of tax attributable to noncontrolling interests	(4)	[2]
Net of tax attributable to MHFG shareholders	¥ 101
[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 and Net income, respectively.

Regulatory Matters - Additional

Regulatory Matters - Additional Information (Detail) - JPY (¥) ¥ in Billions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements [Line Items]
Capital adequacy ratio	120.00%
Increments of capital investment	10.00%
Additional Tier 1 capital	¥ 303
Tier 2 capital	¥ 506.1
Buffer ranging percentage	0.05%	0.01%
Additional loss absorbency requirements for G-SIBs and D-SIBs	1.00%
Leverage ratio	3.00%
Description of regulatory actions for not maintaining the minimum capital ratio concerning securities subsidiaries	A capital ratio of less than 140% will call for regulatory reporting and a capital ratio of less than 100% may lead to a temporary suspension of all or part of the business operations and further, to the cancellation of the license to act as a securities broker and dealer.
Minimum
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements [Line Items]
Buffer ranging percentage	0.00%
Minimum | Regulatory reporting
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements [Line Items]
Capital adequacy ratio	140.00%
Minimum | Temporary suspension
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements [Line Items]
Capital adequacy ratio	100.00%
Maximum
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements [Line Items]
Buffer ranging percentage	2.50%
Basel III
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements [Line Items]
Tier 1 capital ratio	6.00%
Common Equity Tier 1	4.50%
Basel III | Minimum
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements [Line Items]
Capital adequacy ratio	8.00%
March 2016
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements [Line Items]
Additional loss absorbency requirements for G-SIBs and D-SIBs	0.25%

Regulatory Matters (Capital Req

Regulatory Matters (Capital Requirements and Regulatory Adjustments Over Transitional Period) (Detail)		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Countercyclical capital buffer		0.05%	0.01%
Additional loss absorbency requirements for G-SIBs and D-SIBs		1.00%
March 2018
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		8.00%
Phase out of recognition of capital instruments that no longer qualify as capital		40.00%
Capital conservation buffer		1.875%
Countercyclical capital buffer	[1]	0.01%
Additional loss absorbency requirements for G-SIBs and D-SIBs	[2]	0.75%
Minimum Leverage Ratio		3.00%
March 2018 | Common Equity Tier 1 Capital
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		4.50%
March 2018 | Tier I
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		6.00%
March 2019
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		8.00%
Phase out of recognition of capital instruments that no longer qualify as capital		30.00%
Capital conservation buffer		2.50%
Countercyclical capital buffer	[1]	0.05%
Additional loss absorbency requirements for G-SIBs and D-SIBs	[2]	1.00%
Minimum Leverage Ratio		3.00%
March 2019 | Common Equity Tier 1 Capital
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		4.50%
March 2019 | Tier I
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		6.00%
March 2020
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		8.00%
Phase out of recognition of capital instruments that no longer qualify as capital		20.00%
Capital conservation buffer		2.50%
Countercyclical capital buffer	[1]	0.05%
Additional loss absorbency requirements for G-SIBs and D-SIBs	[2]	1.00%
Minimum Leverage Ratio		3.00%
March 2020 | Common Equity Tier 1 Capital
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		4.50%
March 2020 | Tier I
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		6.00%
March 2021
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		8.00%
Phase out of recognition of capital instruments that no longer qualify as capital		10.00%
Capital conservation buffer		2.50%
Countercyclical capital buffer	[1]	0.05%
Additional loss absorbency requirements for G-SIBs and D-SIBs	[2]	1.00%
Minimum Leverage Ratio		3.00%
March 2021 | Common Equity Tier 1 Capital
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		4.50%
March 2021 | Tier I
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		6.00%
March 2022
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		8.00%
Phase out of recognition of capital instruments that no longer qualify as capital		0.00%
Capital conservation buffer		2.50%
Countercyclical capital buffer	[1]	0.05%
Additional loss absorbency requirements for G-SIBs and D-SIBs	[2]	1.00%
Minimum Leverage Ratio	[3]	3.50%
March 2022 | Common Equity Tier 1 Capital
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		4.50%
March 2022 | Tier I
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Minimum total capital		6.00%
[1]	Figures assume that the countercyclical capital buffer will continue to be 0.05% after March 2019.
[2]	Figures assume that the additional loss absorbency requirements applied to the Group as a G-SIB and D-SIB continue to be 1.0% on a fully effective basis in future years.
[3]	This figure includes a leverage ratio buffer required to be met at 50% of the additional loss absorbency requirements applied to the Group as a G-SIB under the finalized Basel III reforms.

Regulatory Matters (Capital R_2

Regulatory Matters (Capital Requirements and Regulatory Adjustments Over Transitional Period) (Parenthetical) (Detail)		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Countercyclical capital buffer		0.05%	0.01%
Additional loss absorbency requirements for G-SIBs and D-SIBs		1.00%
March 2022
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Countercyclical capital buffer	[1]	0.05%
Additional loss absorbency requirements for G-SIBs and D-SIBs	[2]	1.00%
March 2022 | Basel III
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Leverage ratio buffer		50.00%
[1]	Figures assume that the countercyclical capital buffer will continue to be 0.05% after March 2019.
[2]	Figures assume that the additional loss absorbency requirements applied to the Group as a G-SIB and D-SIB continue to be 1.0% on a fully effective basis in future years.

Regulatory Matters (Capital Ade

Regulatory Matters (Capital Adequacy Ratios and Leverage Ratios of MHFG, MHBK, and MHTB Calculated in Accordance with Japanese GAAP and Guidelines Established by Financial Services Agency) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018
Common Equity Tier 1 capital:
Actual		¥ 2,256,768
Required		120.00%
Common Equity Tier 1 capital:
Required		4.50%
Leverage Ratio:
Required		3.00%
Mizuho Financial Group Inc | Consolidated
Common Equity Tier 1 capital:
Required	[1]	¥ 4,661,000	¥ 4,247,000
Actual		7,390,000	7,437,000
Required	[1]	5,529,000	5,140,000
Actual		¥ 9,232,000	¥ 9,192,000
Required	[1]	9.55%	8.635%
Actual		15.94%	15.44%
Required	[1]	¥ 6,687,000	¥ 6,331,000
Actual		¥ 10,918,000	¥ 10,860,000
Required	[2]	11.55%	10.635%
Actual	[3]	18.85%	18.24%
Required		¥ 0	¥ 0
Actual	[3]	0	0
Required		0	0
Actual	[3]	¥ 0	¥ 0
Common Equity Tier 1 capital:
Required	[1]	8.05%	7.135%
Actual		12.76%	12.49%
Leverage Ratio:
Required		3.00%
Actual	[3]	4.42%	4.28%
Mizuho Bank Limited | Consolidated
Common Equity Tier 1 capital:
Required		¥ 2,388,000	¥ 2,400,000
Actual		6,690,000	6,584,000
Required		3,184,000	3,200,000
Actual		¥ 8,527,000	¥ 8,330,000
Required		6.00%	6.00%
Actual		16.06%	15.61%
Required		¥ 4,246,000	¥ 4,267,000
Actual		¥ 10,098,000	¥ 9,881,000
Required		8.00%	8.00%
Actual		19.02%	18.52%
Required		¥ 0	¥ 0
Actual	[3]	0	0
Required		0	0
Actual	[3]	¥ 0	¥ 0
Common Equity Tier 1 capital:
Required		4.50%	4.50%
Actual		12.60%	12.34%
Leverage Ratio:
Required		3.00%
Actual	[3]	4.44%	4.53%
Mizuho Bank Limited | Non-consolidated
Common Equity Tier 1 capital:
Required		¥ 2,272,000	¥ 2,312,000
Actual		6,363,000	6,330,000
Required		3,029,000	3,082,000
Actual		¥ 8,199,000	¥ 8,081,000
Required		6.00%	6.00%
Actual		16.23%	15.73%
Required		¥ 4,039,000	¥ 4,109,000
Actual		¥ 9,757,000	¥ 9,619,000
Required		8.00%	8.00%
Actual		19.32%	18.72%
Common Equity Tier 1 capital:
Required		4.50%	4.50%
Actual		12.60%	12.32%
Leverage Ratio:
Required		3.00%
Actual	[4]	4.45%
Mizuho Trust & Banking Company Limited | Consolidated
Common Equity Tier 1 capital:
Required		¥ 95,000	¥ 112,000
Actual		500,000	498,000
Required		127,000	149,000
Actual		¥ 501,000	¥ 499,000
Required		6.00%	6.00%
Actual		23.70%	20.05%
Required		¥ 169,000	¥ 199,000
Actual		¥ 505,000	¥ 505,000
Required		8.00%	8.00%
Actual		23.87%	20.28%
Required		¥ 0	¥ 0
Actual	[3]	0	0
Required		0	0
Actual	[3]	¥ 0	¥ 0
Common Equity Tier 1 capital:
Required		4.50%	4.50%
Actual		23.67%	19.99%
Leverage Ratio:
Required		3.00%
Actual	[3]	6.55%	7.03%
Mizuho Trust & Banking Company Limited | Non-consolidated
Common Equity Tier 1 capital:
Required		¥ 94,000	¥ 112,000
Actual		494,000	504,000
Required		126,000	149,000
Actual		¥ 494,000	¥ 504,000
Required		6.00%	6.00%
Actual		23.58%	20.28%
Required		¥ 168,000	¥ 199,000
Actual		¥ 498,000	¥ 509,000
Required		8.00%	8.00%
Actual		23.75%	20.50%
Required		¥ 0	¥ 0
Actual	[3]	0	0
Required		0	0
Actual	[3]	¥ 0	¥ 0
Common Equity Tier 1 capital:
Required		4.50%	4.50%
Actual		23.58%	20.28%
Leverage Ratio:
Required		3.00%
Actual	[4]	6.53%
[1]	The required ratios disclosed above, at March 31, 2018 and 2019, include the transitional capital conservation buffer of 1.875% and 2.5%, respectively, the countercyclical capital buffer of 0.01% and 0.05%, respectively, and the transitional additional loss absorbency requirements for G-SIBs and D-SIBs of 0.75% and 1.0%, respectively, 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]	Figures assume that the countercyclical capital buffer will continue to be 0.05% after March 2019.
[3]	The actual leverage ratios disclosed above, at March 31, 2018, are based on the Pillar 3 requirements.
[4]	MHBK and MHTB did not calculate the leverage ratios on non-consolidated basis at March 31, 2018 as they are excluded from the Pillar 3 requirement.

Regulatory Matters (Capital A_2

Regulatory Matters (Capital Adequacy Ratios and Leverage Ratios of MHFG, MHBK, and MHTB Calculated in Accordance with Japanese GAAP and Guidelines Established by Financial Services Agency) (Parenthetical) (Detail)		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Capital conservation buffer		2.50%	1.875%
Additional loss absorbency requirements for G-SIBs and D-SIBs		1.00%
Countercyclical capital buffer		0.05%	0.01%
March 2018
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]	0.75%
Countercyclical capital buffer	[2]	0.01%
March 2019
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]	1.00%
Countercyclical capital buffer	[2]	0.05%
[1]	Figures assume that the additional loss absorbency requirements applied to the Group as a G-SIB and D-SIB continue to be 1.0% on a fully effective basis in future years.
[2]	Figures assume that the countercyclical capital buffer will continue to be 0.05% after March 2019.

Earnings Per Common Share (Comp

Earnings Per Common Share (Computation of Basic and Diluted Earnings Per Common Share) (Detail) - JPY (¥) ¥ / shares in Units, shares in Thousands, ¥ in Millions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Net income:
Net income attributable to MHFG common shareholders		¥ 84,471	¥ 577,608	¥ 362,440
Effect of dilutive securities
Net income attributable to common shareholders after assumed conversions		¥ 84,471	¥ 577,608	¥ 362,440
Shares:
Weighted average common shares outstanding		25,362,376	25,366,345	25,285,899
Effect of dilutive securities:
Convertible preferred stock (Note)	[1]			82,993
Stock options		4,522	7,586	11,410
Weighted average common shares after assumed conversions		25,366,898	25,373,931	25,380,302
Amounts per common share:
Basic net income per common share		¥ 3.33	¥ 22.77	¥ 14.33
Diluted net income per common share		¥ 3.33	¥ 22.76	¥ 14.28
[1]	The number of common shares after assumed conversion of the convertible preferred stock is based on the applicable conversion prices.

Income Taxes (Components of Inc

Income Taxes (Components of Income Tax Expense) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Current:
Domestic	¥ 116,695	¥ 130,573	¥ 130,164
Foreign	49,871	47,020	68,512
Total current tax expense	166,566	177,593	198,676
Deferred:
Domestic	(162,475)	58,078	(99,831)
Foreign	5,244	1,933	(7,601)
Total deferred tax expense (benefit)	(157,231)	60,011	(107,432)
Income tax expense	¥ 9,335	¥ 237,604	¥ 91,244

Income Taxes (Detailed Amounts

Income Taxes (Detailed Amounts of Tax Effects of Items Recorded Directly in Equity) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Net unrealized gains (losses) on available-for-salesecurities:
Unrealized gains (losses)		¥ (3,940)	¥ 123,186	¥ 112,467
Less: reclassification adjustments		889	(82,828)	(97,729)
Total		(3,051)	40,358	14,738
Pension liability adjustments:
Unrealized gains (losses)		(6,558)	66,331	4,785
Less: reclassification adjustments		(2,370)	190	178
Total		(8,928)	66,521	4,963
Own credit risk adjustments:
Unrealized gains (losses)	[1]	3,033
Less: reclassification adjustments	[1]	(47)
Total	[1]	2,986
Total tax effect before allocation to noncontrolling interests		¥ (8,993)	¥ 106,879	¥ 19,701
[1]	The MHFG Group adopted ASU No.2016-01 on April 1, 2018. The ASU requires an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. See Note 2 "Recently issued accounting pronouncements" for further details.

Income Taxes (Reconciliation of

Income Taxes (Reconciliation of Income Tax Expense at Effective Statutory Tax Rate to Actual Income Tax Expense) (Detail) - JPY (¥) ¥ in Millions		Dec. 22, 2017	Mar. 31, 2018	Mar. 31, 2019		Mar. 31, 2018		Mar. 31, 2017
Reconciliation of Income Tax Expense Benefit and Statutory Federal Tax Rate [Line Items]
Income before income tax expense				¥ 85,060		¥ 839,298		¥ 480,375
Effective statutory tax rate		35.00%	21.00%	30.62%		30.86%		30.86%
Income tax calculated at the statutory tax rate				¥ 26,045		¥ 259,007		¥ 148,244
Income not subject to tax				(8,861)		(9,312)		(7,521)
Expenses not deductible for tax purposes				1,389		1,421		1,483
Tax rate differentials of subsidiaries				(3,522)		(2,696)		(2,165)
Change in valuation allowance				(2,444)		(9,102)		112,781	[1]
Change in undistributed earnings of subsidiaries				(21,347)	[2]	(1,972)		5,217
Change in net operating loss carryforwards resulting from intercompany capital transactions								647
Effect of enacted change in tax rates				(11)		6,863	[3]
Reversal of outside basis differences	[1]							(159,119)
Change in unrecognized tax benefits				9,420
Other				8,666		(6,605)		(8,323)
Income tax expense				¥ 9,335		¥ 237,604		¥ 91,244
[1]	These amounts for the fiscal year ended March 31, 2017 represent mainly the reversal of an outside basis difference related to certain foreign subsidiaries due to their organizational restructuring and the related increase in the valuation allowance.
[2]	In the fiscal year ended March 31, 2019, the MHFG Group derecognized majority of deferred tax liabilities for undistributed earnings of foreign subsidiaries because the Group has intent and ability to reinvest those earnings indefinitely in certain foreign subsidiaries.
[3]	On December 22, 2017, the President of the United States signed into law the Tax Cuts and Jobs Act, which includes a reduction in the U.S. federal corporate income tax rate from 35% to 21%. The decrease in the Group's balance of net deferred tax assets, reflecting such tax rate reductions, was recognized as an increase to Income tax expense in the fiscal year ended March 31, 2018.

Income Taxes (Reconciliation _2

Income Taxes (Reconciliation of Income Tax Expense at Effective Statutory Tax Rate to Actual Income Tax Expense) (Parenthetical) (Detail)	Dec. 22, 2017	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Reconciliation of Income Tax Expense Benefit and Statutory Federal Tax Rate [Line Items]
Effective statutory tax rate	35.00%	21.00%	30.62%	30.86%	30.86%

Income Taxes (Components of Net

Income Taxes (Components of Net Deferred Tax Assets (Liabilities)) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019		Mar. 31, 2018		Mar. 31, 2017	Apr. 01, 2016
Deferred tax assets:
Allowance for loan losses		¥ 122,585		¥ 126,977
Premises and equipment		73,944		4,896
Derivative financial instruments		48,487		53,336
Investments				453,880
Trading securities				1,988
Net operating loss carryforwards (Note)	[1]	167,755		178,256
Other		216,568		204,005
Deferred Tax Assets, Gross, Total		629,339		1,023,338
Valuation allowance (Note)		(158,581)	[1]	(163,358)	[1]	¥ (438,344)	¥ (339,922)
Deferred tax assets, net of valuation allowance		470,758		859,980
Deferred tax liabilities:
Prepaid pension cost and accrued pension liabilities		247,694		255,239
Investments		198,495
Available-for-salesecurities		12,426		764,497
Trading securities		9,158
Other		61,330		89,359
Deferred tax liabilities		529,103		1,109,095
Net deferred tax assets (liabilities)		¥ (58,345)		¥ (249,115)
[1]	The amount includes ¥110,729 million and ¥107,246 million related to MHSC's net operating loss carryforwards resulting mainly from the organizational restructuring of certain foreign subsidiaries as of March 31, 2018 and 2019, respectively. The tax effect of the net operating loss carryforwards is substantially offset by ¥86,189 million and ¥88,294 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income.

Income Taxes (Components of N_2

Income Taxes (Components of Net Deferred Tax Assets (Liabilities)) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019		Mar. 31, 2018		Mar. 31, 2017	Apr. 01, 2016
Schedule of Deferred Income Tax Assets and Liabilities [Line Items]
Net operating loss carryforwards	[1]	¥ 167,755		¥ 178,256
Valuation allowance		158,581	[1]	163,358	[1]	¥ 438,344	¥ 339,922
Mizuho Securities Company Limited
Schedule of Deferred Income Tax Assets and Liabilities [Line Items]
Net operating loss carryforwards		107,246		110,729
Valuation allowance		¥ 88,294		¥ 86,189
[1]	The amount includes ¥110,729 million and ¥107,246 million related to MHSC's net operating loss carryforwards resulting mainly from the organizational restructuring of certain foreign subsidiaries as of March 31, 2018 and 2019, respectively. The tax effect of the net operating loss carryforwards is substantially offset by ¥86,189 million and ¥88,294 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income.

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Income Taxes [Line Items]
Deferred tax liabilities	¥ 58,345	¥ 249,115
Changes that directly affected the Income tax expense	2,444	9,102	¥ (112,781)
Others	2,333	1,650	14,359
Net operating loss carryforwards	683,000
Unrecognized tax benefits, that would affect effective tax rate	12,323	2,345	1,867
Unrecognized tax benefits, interest and penalties	2,164	¥ 888	¥ 675
Unrecognized tax benefits within the next twelve months	¥ 9,000
Japan
Income Taxes [Line Items]
Open tax year	2010
United States of America
Income Taxes [Line Items]
Open tax year	2002
United Kingdom
Income Taxes [Line Items]
Open tax year	2015
Mizuho Securities Company Limited | Restructuring Charges | Minimum
Income Taxes [Line Items]
Operating loss carryforwards, expiration date	Mar. 31, 2026
Mizuho Securities Company Limited | Organizational Restructuring
Income Taxes [Line Items]
Net operating loss carryforwards	¥ 350,000
Mizuho Securities Company Limited | Japan
Income Taxes [Line Items]
Operating loss carryforwards, expiration date	Mar. 31, 2026	Mar. 31, 2026
Mizuho Financial Group Inc
Income Taxes [Line Items]
Undistributed earnings	¥ 186,000
Deferred tax liabilities	¥ 17,000

Income Taxes (Breakdown of Net

Income Taxes (Breakdown of Net Operating Loss Carryforwards by Tax Jurisdiction) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019		Mar. 31, 2018
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards	[1]	¥ 167,755		¥ 178,256
Operating loss, Valuation allowance		(140,000)		(139,000)
Deferred tax assets,Operating loss carryforward net of valuation allowance		28,000		39,000
Japan
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards		111,000	[2]	117,000	[3]
Operating loss, Valuation allowance		(92,000)	[2]	(88,000)	[3]
Deferred tax assets,Operating loss carryforward net of valuation allowance		19,000	[2]	29,000	[3]
United States of America
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards		8,000		10,000
Operating loss, Valuation allowance				(1,000)
Deferred tax assets,Operating loss carryforward net of valuation allowance		8,000		9,000
United Kingdom
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards	[4]	46,000		48,000
Operating loss, Valuation allowance	[4]	(46,000)		(48,000)
Others
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards		3,000		3,000
Operating loss, Valuation allowance		(2,000)		(2,000)
Deferred tax assets,Operating loss carryforward net of valuation allowance		¥ 1,000		¥ 1,000
[1]	The amount includes ¥110,729 million and ¥107,246 million related to MHSC's net operating loss carryforwards resulting mainly from the organizational restructuring of certain foreign subsidiaries as of March 31, 2018 and 2019, respectively. The tax effect of the net operating loss carryforwards is substantially offset by ¥86,189 million and ¥88,294 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income.
[2]	¥107 billion of the Japan deferred tax assets of ¥111 billion is related to MHSC, which is substantially offset by a valuation allowance, and will expire during the fiscal year ending March 31, 2026.
[3]	¥111 billion of the Japan deferred tax assets of ¥117 billion is related to MHSC, which is substantially offset by a valuation allowance, and will expire during the fiscal year ending March 31, 2026.
[4]	The United Kingdom net operating loss carryforwards may be carried forward indefinitely for tax purposes.

Income Taxes (Breakdown of Ne_2

Income Taxes (Breakdown of Net Operating Loss Carryforwards by Tax Jurisdiction) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019		Mar. 31, 2018
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards	[1]	¥ 167,755		¥ 178,256
Japan
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards		111,000	[2]	117,000	[3]
Mizuho Securities Company Limited
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards		107,246		110,729
Mizuho Securities Company Limited | Japan
Operating Loss Carryforwards [Line Items]
Deferred tax assets, operating loss carryforwards		¥ 107,000		¥ 111,000
Operating loss carryforwards, expiration date		Mar. 31, 2026		Mar. 31, 2026
[1]	The amount includes ¥110,729 million and ¥107,246 million related to MHSC's net operating loss carryforwards resulting mainly from the organizational restructuring of certain foreign subsidiaries as of March 31, 2018 and 2019, respectively. The tax effect of the net operating loss carryforwards is substantially offset by ¥86,189 million and ¥88,294 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income.
[2]	¥107 billion of the Japan deferred tax assets of ¥111 billion is related to MHSC, which is substantially offset by a valuation allowance, and will expire during the fiscal year ending March 31, 2026.
[3]	¥111 billion of the Japan deferred tax assets of ¥117 billion is related to MHSC, which is substantially offset by a valuation allowance, and will expire during the fiscal year ending March 31, 2026.

Income Taxes (Roll-forward of V

Income Taxes (Roll-forward of Valuation Allowance) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019		Mar. 31, 2018		Mar. 31, 2017
Valuation Allowance [Line Items]
Balance at beginning of fiscal year	¥ 163,358	[1]	¥ 438,344		¥ 339,922
Changes that directly affected Income tax expense	(2,444)		(9,102)		112,781
Expiration of net operating loss carryforwards			(264,234)
Others	(2,333)		(1,650)		(14,359)
Total	(2,333)		(265,884)		(14,359)
Balance at end of fiscal year	¥ 158,581	[1]	¥ 163,358	[1]	¥ 438,344
[1]	The amount includes ¥110,729 million and ¥107,246 million related to MHSC's net operating loss carryforwards resulting mainly from the organizational restructuring of certain foreign subsidiaries as of March 31, 2018 and 2019, respectively. The tax effect of the net operating loss carryforwards is substantially offset by ¥86,189 million and ¥88,294 million, respectively, of valuation allowance as a result of considering all available evidence regarding sources of future taxable income including historical trends in taxable income in the preceding periods and forecasted taxable income.

Income Taxes (Net Operating Los

Income Taxes (Net Operating Losses Carryforwards by Expiration Date) (Detail) ¥ in Billions	Mar. 31, 2019JPY (¥)
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	¥ 683
2023
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	12
2024
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	3
2025 and thereafter
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	¥ 668

Income Taxes (Roll-forward of U

Income Taxes (Roll-forward of Unrecognized Tax Benefits) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Operating Loss Carryforwards [Line Items]
Total unrecognized tax benefits at beginning of fiscal year	¥ 2,345	¥ 1,867	¥ 1,300
Gross amount of increases (decreases) related to positions taken during prior years	9,550	224	167
Gross amount of increases related to positions taken during the current year	330	351	409
Amount of decreases related to settlements	0	0	0
Foreign exchange translation	98	(97)	(9)
Total unrecognized tax benefits at end of fiscal year	¥ 12,323	¥ 2,345	¥ 1,867

Pension and Other Employee Be_3

Pension and Other Employee Benefit Plans - Additional Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plans, costs recognized in respect of contributions to the plans	¥ 3,217	¥ 2,511	¥ 3,141
Amounts in accumulated other comprehensive income (loss) expected to be amortized as prior service cost or benefits over the next fiscal year	163
Amounts in accumulated other comprehensive income (loss) expected to be amortized as actuarial gain over the next fiscal year	5,627
Aggregated accumulated benefit obligations	¥ 1,590,818	¥ 1,559,356
Description of requirements for lump-sum severance indemnities	Employees with service in excess of one year are qualified to receive lump-sum severance indemnities.
Pension plan, contribution expected to be paid during the next fiscal year	¥ 52,000

Pension and Other Employee Be_4

Pension and Other Employee Benefit Plans (Components of Net Periodic Costs of Severance Indemnities and Pension Plans) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Service cost-benefits earned during the fiscal year	¥ 43,698	¥ 43,649	¥ 44,367
Interest costs on projected benefit obligations	6,933	7,471	5,724
Expected return on plan assets	(38,518)	(34,916)	(35,969)
Amortization of prior service cost (benefits)	152	214	(195)
Amortization of net actuarial loss (gain)	(7,886)	411	780
Special termination benefits	2,929	3,960	3,857
Net periodic benefit cost	¥ 7,308	¥ 20,789	¥ 18,564

Pension and Other Employee Be_5

Pension and Other Employee Benefit Plans (Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss) Before-Tax) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Net actuarial gain (loss)	¥ (21,300)	¥ 216,777
Amortization of net actuarial loss (gain)	(7,886)	411
Prior service benefits (cost)	(109)	(348)
Amortization of prior service cost (benefits)	152	214
Total recognized in other comprehensive income (loss) before-tax	¥ (29,143)	¥ 217,054

Pension and Other Employee Be_6

Pension and Other Employee Benefit Plans (Weighted-Average Assumptions Used to Determine Benefit Obligations and Net Periodic Benefit Cost) (Detail)	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Weighted-average assumptions used to determine benefit obligations at fiscal year end:
Discount rates	0.34%	0.43%	0.47%
Minimum
Weighted-average assumptions used to determine benefit obligations at fiscal year end:
Rates of increase in future compensation levels	1.80%	1.80%	1.80%
Weighted-average assumptions used to determine net periodic benefit cost during the year:
Rates of increase in future compensation levels	1.80%	1.80%	1.80%
Maximum
Weighted-average assumptions used to determine benefit obligations at fiscal year end:
Rates of increase in future compensation levels	4.80%	4.80%	4.80%
Weighted-average assumptions used to determine net periodic benefit cost during the year:
Discount rates	0.43%	0.47%	0.37%
Rates of increase in future compensation levels	4.80%	4.80%	4.80%
Expected rates of return on plan assets	1.60%	1.58%	1.73%

Pension and Other Employee Be_7

Pension and Other Employee Benefit Plans (Combined Funded Status and Amounts Recognized in Accompanying Consolidated Balance Sheets) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Change in benefit obligations:
Benefit obligations at beginning of fiscal year		¥ 1,559,356	¥ 1,545,893
Service cost		43,698	43,649	¥ 44,367
Interest cost		6,933	7,471	5,724
Plan participants' contributions		1,229	1,233
Amendments		109	348
Actuarial loss (gain)		49,085	30,633
Foreign exchange translation		(817)	(32)
Benefits paid		(52,618)	(53,167)
Lump-sum payments		(16,157)	(16,672)
Benefit obligations at end of fiscal year		1,590,818	1,559,356	1,545,893
Change in plan assets:
Fair value of plan assets at beginning of fiscal year		2,405,730	2,200,812
Actual return (negative return) on plan assets		66,652	280,251
Foreign exchange translation		(390)	(113)
Partial withdrawal of assets from employee retirement benefits trusts (Note)	[1]	(27,534)	(66,565)
Employer contributions		20,487	43,279
Plan participants' contributions		1,229	1,233
Benefits paid		(52,618)	(53,167)
Fair value of plan assets at end of fiscal year		2,413,556	2,405,730	¥ 2,200,812
Funded status		822,738	846,374
Amounts recognized in the consolidated balance sheets consist of:
Prepaid pension cost		850,472	874,191
Accrued pension liability		(27,734)	(27,817)
Net amount recognized		822,738	846,374
Amounts recognized in Accumulated other comprehensive income (loss) before-tax consist of:
Prior service benefits (cost)		(1,309)	(1,352)
Net actuarial gain (loss)		262,044	291,230
Net amount recognized		¥ 260,735	¥ 289,878
[1]	During the fiscal year ended March 31, 2018 and 2019, a subsidiary of MHFG partially withdrew assets from employee retirement benefit trusts, which were established for the payment of employees' severance pay and retirement pensions. Overall, the trusts remain in overfunded status as of March 31, 2018 and 2019. No gains or losses have been recognized as a result of this transaction.

Pension and Other Employee Be_8

Pension and Other Employee Benefit Plans (Combined Funded Status and Amounts Recognized in Accompanying Consolidated Balance Sheets) (Parenthetical) (Detail)	12 Months Ended
	Mar. 31, 2019JPY (¥)
Defined Benefit Plan Disclosure [Line Items]
Gain (loss) recognized	¥ 0

Pension and Other Employee Be_9

Pension and Other Employee Benefit Plans (Plans with Projected Benefit Obligations in Excess of Plan Assets and Plans with Accumulated Benefit Obligations in Excess of Plan Assets) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	[1]	¥ 61,579	¥ 59,319
Fair value of plan assets		33,845	31,503
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations		61,579	59,319
Fair value of plan assets		¥ 33,845	¥ 31,503
[1]	The plans with projected benefit obligations in excess of plan assets include those with accumulated benefit obligations in excess of plan assets.

Pension and Other Employee B_10

Pension and Other Employee Benefit Plans (Target Allocation for Plan Assets Excluding those of Employee Retirement Benefit Trusts) (Detail)	Mar. 31, 2019
Asset category
Plan assets	100.00%
General Account Assets
Asset category
Plan assets	11.00%	[1]
Other assets
Asset category
Plan assets	2.00%
Foreign | Equity securities
Asset category
Plan assets	25.00%
Foreign | Debt securities
Asset category
Plan assets	23.00%
Japan | Equity securities
Asset category
Plan assets	5.00%
Japan | Debt securities
Asset category
Plan assets	34.00%
[1]	General account of life insurance companies is a contract with life insurance companies which guarantees payments of principal and predetermined interest payments.

Pension and Other Employee B_11

Pension and Other Employee Benefit Plans (Fair Value of Plan Assets by Asset Category) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018		Mar. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		¥ 2,413,556	¥ 2,405,730		¥ 2,200,812
Foreign | Common stocks | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		120,000	108,000
Foreign | Pooled funds | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[1]	5,000	5,000
Foreign | Pooled funds | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[1]	10,000	9,000
Foreign | Government bonds | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		184,000	181,000
Foreign | Other | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		18,000	16,000
All Other | General account of life insurance companies
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[2]	111,000	110,000
All Other | Other Invested Assets
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		83,000	92,000
All Other | Net Asset Value
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[3]	327,000	323,000
Japan | Common stocks | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[4]	1,317,000	1,330,000
Japan | Pooled funds | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[1]	15,000	19,000
Japan | Pooled funds | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[1]	10,000	4,000
Japan | Government bonds | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		190,000	184,000
Japan | Other | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		24,000	25,000
Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		1,895	1,899
Level 1 | Foreign | Common stocks | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		120,000	108,000
Level 1 | Foreign | Government bonds | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		178,000	175,000
Level 1 | All Other | Other Invested Assets
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[5]	79,000	92,000	[6]
Level 1 | Japan | Common stocks | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[4]	1,317,000	1,330,000
Level 1 | Japan | Pooled funds | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[1]	11,000	10,000
Level 1 | Japan | Government bonds | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		190,000	184,000
Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		192	184
Level 2 | Foreign | Pooled funds | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[1]	5,000	5,000
Level 2 | Foreign | Pooled funds | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[1]	10,000	9,000
Level 2 | Foreign | Government bonds | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		6,000	6,000
Level 2 | Foreign | Other | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		18,000	16,000
Level 2 | All Other | General account of life insurance companies
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[2]	111,000	110,000
Level 2 | All Other | Other Invested Assets
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		4,000
Level 2 | Japan | Pooled funds | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[1]	4,000	9,000
Level 2 | Japan | Pooled funds | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	[1]	10,000	4,000
Level 2 | Japan | Other | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		¥ 24,000	¥ 25,000
[1]	These classes primarily include pension investment fund trusts. Investments in these classes are generally measured at fair value and can be redeemed within a short-term period upon request.
[2]	Investments in this class are measured at conversion value, which is equivalent to fair value.
[3]	In accordance with ASC 820, certain plan assets that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy.
[4]	This class represents equity securities held in the employee retirement benefit trusts of ¥1,330 billion and ¥1,317 billion carried at fair value at March 31, 2018 and 2019, respectively, which are well-diversified across industries.
[5]	Amounts primarily include cash and short-term assets carried at fair value.
[6]	Derivative receivables and payables are recorded in Trading account assets and Trading account liabilities, respectively.

Pension and Other Employee B_12

Pension and Other Employee Benefit Plans (Fair Value of Plan Assets by Asset Category) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Equity securities held in the employee retirement benefit trusts		¥ 2,413,556	¥ 2,405,730	¥ 2,200,812
Equity securities | Common stocks | Japan
Defined Benefit Plan Disclosure [Line Items]
Equity securities held in the employee retirement benefit trusts	[1]	1,317,000	1,330,000
Equity securities | Common stocks | Trust for Benefit of Employees | Japan
Defined Benefit Plan Disclosure [Line Items]
Equity securities held in the employee retirement benefit trusts		¥ 1,317,000	¥ 1,330,000
[1]	This class represents equity securities held in the employee retirement benefit trusts of ¥1,330 billion and ¥1,317 billion carried at fair value at March 31, 2018 and 2019, respectively, which are well-diversified across industries.

Pension and Other Employee B_13

Pension and Other Employee Benefit Plans (Forecasted Benefit Payments Including Effect of Expected Future Service) (Detail) ¥ in Millions	Mar. 31, 2019JPY (¥)
Defined Benefit Plan Disclosure [Line Items]
2020	¥ 68,890
2021	70,015
2022	70,637
2023	71,370
2024	72,606
2025-2029	¥ 351,719

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) ¥ / shares in Units, ¥ in Millions	12 Months Ended
	Mar. 31, 2019JPY (¥)¥ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation plan, exercise price per share	¥ 0
Cash deferred graded-vesting period	3 years
Compensation cost related to non-vested awards not yet recognized | ¥	¥ 1,757
Performance-based stock compensation, recognition period	1 year 8 months 26 days
MHFG Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation plan, shares of common stock to be issued or transferred upon exercise of each of the stock acquisition rights | shares	1,000
Stock-based compensation plan, exercise price per share	¥ 1
Stock-based compensation plan, contractual term (in years)	20 years

Stock-Based Compensation (Summa

Stock-Based Compensation (Summary of Stock-Based Compensation Plan) (Detail) ¥ / shares in Units, ¥ in Millions	12 Months Ended
	Mar. 31, 2019JPY (¥)¥ / sharesshares
Number of shares
Outstanding at beginning of fiscal year | shares	7,216,000
Exercised during fiscal year | shares	2,971,000
Outstanding at end of fiscal year | shares	4,245,000
Exercisable at end of fiscal year | shares	0
Weighted-average exercise price
Outstanding at beginning of fiscal year | ¥ / shares	¥ 1
Exercised during fiscal year | ¥ / shares	1
Outstanding at end of fiscal year | ¥ / shares	1
Exercisable at end of fiscal year | ¥ / shares	¥ 0
Weighted-average remaining contractual term
Outstanding at end of fiscal year	14 years 9 months 21 days
Exercisable at end of fiscal year	0 years
Aggregate intrinsic value
Outstanding at end of fiscal year | ¥	¥ 723
Exercisable at end of fiscal year | ¥	¥ 0

Stock-Based Compensation (Activ

Stock-Based Compensation (Activities Related to Performance-based Stock Compensation) (Detail) - Performance-based stock compensation - ¥ / shares	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Stock Compensation Plan I
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, Granted during fiscal year	3,770,065
Number of shares, Vested during fiscal year	3,770,065
Number of shares, Forfeited during fiscal year	0	0
Weighted-average grant-date fair value, Granted during fiscal year	¥ 189.24
Weighted-average grant-date fair value, Vested during fiscal year	189.24
Weighted-average grant-date fair value, Forfeited during fiscal year	¥ 0	¥ 0
Stock Compensation Plan II
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested at the beginning of the year	13,319,406	9,000,000
Number of shares, Granted during fiscal year	6,906,635	8,130,000
Number of shares, Vested during fiscal year	5,068,949	3,810,594
Number of shares, Forfeited during fiscal year	0	0
Nonvested at the end of the year	15,157,092	13,319,406
Weighted-average grant-date fair value, Nonvested at the beginning of the year	¥ 182.04	¥ 158.68
Weighted-average grant-date fair value, Granted during fiscal year	189.24	196.94
Weighted-average grant-date fair value, Vested during fiscal year	187.48	158.68
Weighted-average grant-date fair value, Forfeited during fiscal year	0	0
Weighted-average grant-date fair value, Nonvested at the ending of the year	¥ 183.50	¥ 182.04

Stock-based Compensation - Stoc

Stock-based Compensation - Stock Option Activity (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Stock Compensation Plan I
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of vested shares	¥ 713
Common stock shares acquired	713
Stock Compensation Plan II
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of vested shares	930	¥ 782
Common stock shares acquired	¥ 1,307	¥ 1,601

Stock-based Compensation - Sche

Stock-based Compensation - Schedule Of Stock-Based Compensation Expense (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Stock Compensation Plan I
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
The compensation cost recognized	¥ 713
Stock Compensation Plan II
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
The compensation cost recognized	¥ 1,287	¥ 868	¥ 354

Derivative Financial Instrume_3

Derivative Financial Instruments (Summary of Notional and Fair Value Amounts of Derivative Instruments Outstanding) (Detail) - JPY (¥) ¥ in Billions		Mar. 31, 2019	Mar. 31, 2018
Derivatives, Fair Value [Line Items]
Notional amount	[1]	¥ 1,227,208	¥ 1,169,233
Interest rate contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	1,052,267	1,004,169
Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	166,383	155,832
Equity-related contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	5,181	6,189
Credit-related contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	2,939	2,708
Other contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	438	335
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]		2
Fair value of derivative payables	[2]		9
Designated as Hedging Instrument | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]		2
Designated as Hedging Instrument | Equity-related contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative payables	[2]		9
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	7,904	10,109
Fair value of derivative payables	[2]	7,541	9,707
Not Designated as Hedging Instrument | Interest rate contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	5,786	7,176
Fair value of derivative payables	[2]	5,610	7,143
Not Designated as Hedging Instrument | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	1,959	2,695
Fair value of derivative payables	[2]	1,758	2,382
Not Designated as Hedging Instrument | Equity-related contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	125	197
Fair value of derivative payables	[2]	142	142
Not Designated as Hedging Instrument | Credit-related contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	18	18
Fair value of derivative payables	[2]	17	21
Not Designated as Hedging Instrument | Other contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	16	23
Fair value of derivative payables	[2]	¥ 14	¥ 19
[1]	Notional amount includes the sum of gross long and gross short third-party contracts.
[2]	Derivative receivables and payables are recorded in Trading account assets and Trading account liabilities, respectively.

Derivative Financial Instrume_4

Derivative Financial Instruments - Additional Information (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2019	Mar. 31, 2018
Derivative [Line Items]
Cash collateral provided and not offset against derivative positions and included in Other assets	¥ 856,439	¥ 981,390
Cash collateral accepted and not offset against derivative positions and included in Other liabilities	¥ 589,411	¥ 598,524

Derivative Financial Instrume_5

Derivative Financial Instruments (Summary of Gains and Losses Information Related to Fair Value Hedges) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income- Derivatives	¥ (23,832)	¥ (14,747)
Gains (losses) recorded in income- Hedged items	19,631	11,393
Gains (losses) recorded in income- Hedge ineffectiveness	0	0
Gains (losses) recorded in income- Net gain (loss) excluded from assessment of effectiveness	(4,201)	(3,354)
Equity-related contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income- Derivatives	(23,832)	(14,747)
Gains (losses) recorded in income- Hedged items	19,631	11,393
Gains (losses) recorded in income- Hedge ineffectiveness	0	0
Gains (losses) recorded in income- Net gain (loss) excluded from assessment of effectiveness	¥ (4,201)	¥ (3,354)

Derivative Financial Instrume_6

Derivative Financial Instruments (Summary of Gains and Losses Information Related to Net Investment Hedges) (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Effective portion recorded in OCI	¥ 7,405	¥ (30)	¥ 16,767
Ineffective portion recorded in income	107	90	47
Financial instruments hedging foreign exchange risk
Derivative Instruments, Gain (Loss) [Line Items]
Effective portion recorded in OCI	7,405	(30)	16,767
Ineffective portion recorded in income	¥ 107	¥ 90	¥ 47

Derivative Financial Instrume_7

Derivative Financial Instruments (Summary of Gains and Losses Information Related to Net Investment Hedges) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Financial instruments hedging foreign exchange risk
Derivative Instruments, Gain (Loss) [Line Items]
Accumulated other comprehensive income reclassified to earnings	¥ 186	¥ 0	¥ 41

Derivative Financial Instrume_8

Derivative Financial Instruments (Summary of Gains and Losses on Derivatives not Designated or Qualifying as Hedges) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		¥ 169,943	¥ (93,321)	¥ (173,053)
Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		127,242	(63,260)	(209,361)
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		6,748	61,046	37,129
Equity-related contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income	[1]	37,875	(94,607)	5,131
Credit-related contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income	[2]	(467)	(2,830)	(6,694)
Other contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		¥ (1,455)	¥ 6,330	¥ 742
[1]	The net gain (loss) excluded from the assessment of the effectiveness of fair value hedges is not included in the above table.
[2]	Amounts include the net loss of ¥7,594 million, ¥754 million and ¥736 million on the credit derivatives economically managing the credit risk of loans during the fiscal years ended March 31, 2017, 2018 and 2019, respectively.

Derivative Financial Instrume_9

Derivative Financial Instruments (Summary of Gains and Losses on Derivatives not Designated or Qualifying as Hedges) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		¥ 169,943	¥ (93,321)	¥ (173,053)
Credit-related contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income	[1]	(467)	(2,830)	(6,694)
Credit-related contracts | Loans related to credit derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		¥ (736)	¥ (754)	¥ (7,594)
[1]	Amounts include the net loss of ¥7,594 million, ¥754 million and ¥736 million on the credit derivatives economically managing the credit risk of loans during the fiscal years ended March 31, 2017, 2018 and 2019, respectively.

Derivative Financial Instrum_10

Derivative Financial Instruments (Summary of Notional and Fair Value Amounts of Credit Derivatives) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2019	Mar. 31, 2018
Credit protection written
Credit Derivatives [Line Items]
Notional amount	¥ 1,465	¥ 1,302
Fair value	15	19
Credit protection written | Investment grade
Credit Derivatives [Line Items]
Notional amount	1,266	1,105
Fair value	12	15
Credit protection written | Non-investment grade
Credit Derivatives [Line Items]
Notional amount	199	197
Fair value	3	4
Credit protection purchased
Credit Derivatives [Line Items]
Notional amount	1,628	1,541
Fair value	¥ (14)	¥ (22)

Derivative Financial Instrum_11

Derivative Financial Instruments (Maximum Potential Amount of Future Payments for Credit Protection Written by Expiration Period) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2019	Mar. 31, 2018
Credit Derivatives [Line Items]
Maximum payout/Notional amount	¥ 1,465	¥ 1,302
One year or less
Credit Derivatives [Line Items]
Maximum payout/Notional amount	326	329
After one year through five years
Credit Derivatives [Line Items]
Maximum payout/Notional amount	1,057	831
After five years
Credit Derivatives [Line Items]
Maximum payout/Notional amount	¥ 82	¥ 142

Derivative Financial Instrum_12

Derivative Financial Instruments (Quantitative Information about Derivative Instruments with Credit-risk-related Contingent Features) (Detail) - JPY (¥) ¥ in Billions		Mar. 31, 2019	Mar. 31, 2018
Credit Derivatives [Line Items]
Aggregate fair value of derivative instruments with credit-risk-related contingent features in net liability positions		¥ 511	¥ 572
Collateral provided to counterparties in the normal course of business		489	¥ 593
Amount required to be posted as collateral or settled immediately if credit-risk-related contingent features were triggered	[1]	¥ 22
[1]	There was no amount that the Group would be required to post as collateral or settle immediately on March 31, 2018.

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Commitments and Contingencies Disclosure [Line Items]
Carrying amount of guarantees and similar obligations	¥ 109,000	¥ 82,000
Carrying amounts of derivatives that are deemed to guarantees	90,000	62,000
Total rental expense	¥ 115,239	117,270	¥ 113,991
Sale Leaseback transactions accounted as an operating leases, minimum lease back periods	5 years
Sale Leaseback transactions accounted as an operating leases, maximum lease back periods	10 years
Sale Leaseback transactions accounted as an operating leases, total rental payment for the whole period in the original contracts	¥ 214,690
Sale Leaseback transactions accounted as an operating leases, total rental payment for the whole period in the current contracts	282,832
Sale Leaseback transactions accounted as an operating leases, future minimum rental payments	24,525	32,977	¥ 41,430
Off-balance Sheet instruments
Commitments and Contingencies Disclosure [Line Items]
Allowance for losses on off-balance-sheet instruments	¥ 80,000	¥ 90,000

Commitments and Contingencies_2

Commitments and Contingencies (Summary of Maximum Potential Amount of Future Payments under Guarantees) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2019	Mar. 31, 2018
Performance guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	¥ 2,307	¥ 2,165
Guarantees on loans
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	289	241
Guarantees on securities
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	145	164
Other guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	2,324	2,210
Guarantees for repayment of trust principal
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	65	709
Liabilities of trust accounts
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	362	13,861
Derivative financial instruments
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	14,170	11,654
One year or less | Performance guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	1,265	1,084
One year or less | Guarantees on loans
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	164	123
One year or less | Guarantees on securities
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	91	32
One year or less | Other guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	1,447	1,555
One year or less | Guarantees for repayment of trust principal
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount		639
One year or less | Liabilities of trust accounts
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	61	13,546
One year or less | Derivative financial instruments
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	5,807	4,911
After one year through five years | Performance guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	878	908
After one year through five years | Guarantees on loans
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	46	28
After one year through five years | Guarantees on securities
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	54	132
After one year through five years | Other guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	834	614
After one year through five years | Guarantees for repayment of trust principal
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	47	49
After one year through five years | Liabilities of trust accounts
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	148	149
After one year through five years | Derivative financial instruments
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	6,434	4,996
After five years | Performance guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	164	173
After five years | Guarantees on loans
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	79	90
After five years | Other guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	43	41
After five years | Guarantees for repayment of trust principal
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	18	21
After five years | Liabilities of trust accounts
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	153	166
After five years | Derivative financial instruments
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	¥ 1,929	¥ 1,747

Commitments and Contingencies_3

Commitments and Contingencies (Summary of Maximum Potential Amount of Future Payments of Certain Guarantees Classified Based on Internal Ratings) (Detail) - Performance guarantees, Guarantees on loans, Guarantees on securities and Other guarantees - JPY (¥) ¥ in Billions		Mar. 31, 2019	Mar. 31, 2018
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount		¥ 5,065	¥ 4,780
Investment grade
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	[1]	4,124	3,930
Non-investment grade
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount		¥ 941	¥ 850
[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		Mar. 31, 2019	Mar. 31, 2018
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance-sheet instruments, contractual amounts of the undrawn commitments		¥ 77,635	¥ 79,138
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]	76,857	78,448
Commercial letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance-sheet instruments, contractual amounts of the undrawn commitments		¥ 778	¥ 690
[1]	Commitments to extend credit include commitments to invest in securities.

Commitments and Contingencies_5

Commitments and Contingencies (Future Minimum Lease Payments for Capitalized Leases and Rental Payments for Operating Leases) (Detail) ¥ in Millions	Mar. 31, 2019JPY (¥)
Capitalized leases
2020	¥ 9,942
2021	7,347
2022	4,454
2023	2,661
2024	915
2025 and thereafter	222
Total minimum lease/rental payments	25,541
Amount representing interest	25,020
Present value of minimum lease payments	521
Operating leases
2020	51,329
2021	41,227
2022	34,707
2023	24,633
2024	23,425
2025 and thereafter	297,183
Total minimum lease/rental payments	¥ 472,504

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 Billions	Mar. 31, 2019	Mar. 31, 2018
Variable Interest Entity [Line Items]
Consolidated VIEs- Consolidated assets	¥ 6,048	¥ 5,868
Significant unconsolidated VIEs- Total assets	1,350	1,969
Significant unconsolidated VIEs- Maximum exposure to loss	418	538
Asset-backed commercial paper/loan programs
Variable Interest Entity [Line Items]
Consolidated VIEs- Consolidated assets	2,249	2,185
Asset-backed securitizations
Variable Interest Entity [Line Items]
Consolidated VIEs- Consolidated assets	571	627
Significant unconsolidated VIEs- Total assets	70	78
Significant unconsolidated VIEs- Maximum exposure to loss	8	5
Investments in securitization products
Variable Interest Entity [Line Items]
Consolidated VIEs- Consolidated assets	372	374
Investment funds
Variable Interest Entity [Line Items]
Consolidated VIEs- Consolidated assets	2,836	2,661
Significant unconsolidated VIEs- Total assets	1,280	1,891
Significant unconsolidated VIEs- Maximum exposure to loss	410	533
Trust arrangements and other
Variable Interest Entity [Line Items]
Consolidated VIEs- Consolidated assets	¥ 20	¥ 21

Variable Interest Entities an_4

Variable Interest Entities and Securitizations (Carrying Amounts and Classification of Assets and Liabilities on Consolidated Balance Sheets that Relate to Variable Interests in Significant Unconsolidated VIEs) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Assets on balance sheets related to unconsolidated VIEs:
Trading account assets		¥ 21,018,230	¥ 24,302,543
Loans		82,492,742	83,204,742
Total		197,611,195	204,255,642	¥ 200,456,300
Liabilities on balance sheets and maximum exposure to loss related to unconsolidated VIEs:
Payables under securities lending transactions		1,797,737	1,832,870
Trading account liabilities		10,120,968	13,115,270
Total		188,109,702	194,751,942
Maximum exposure to loss		418,000	538,000
Unconsolidated VIEs
Assets on balance sheets related to unconsolidated VIEs:
Trading account assets		104,000	89,000
Investments		168,000	210,000
Loans		71,000	163,000
Total		343,000	462,000
Liabilities on balance sheets and maximum exposure to loss related to unconsolidated VIEs:
Payables under securities lending transactions		47,000	38,000
Trading account liabilities		1,000	1,000
Total		48,000	39,000
Maximum exposure to loss	[1]	¥ 418,000	¥ 538,000
[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	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Variable Interest Entity [Line Items]
Total assets	¥ 197,611,195	¥ 204,255,642	¥ 200,456,300
Noncontrolling interests	774,974	635,279
Total liabilities	188,109,702	194,751,942
Long-term debt	11,529,400	12,955,230
Debt Instrument [Member]
Variable Interest Entity [Line Items]
Long-term debt	681,000	950,000
Consolidated certain investment funds | Restatement Adjustment
Variable Interest Entity [Line Items]
Total assets	16,000
Noncontrolling interests	16,000
Deconsolidated certain investment funds | Restatement Adjustment
Variable Interest Entity [Line Items]
Total assets	54,000
Noncontrolling interests	27,000
Total liabilities	27,000
Assets associated with securitization transactions
Variable Interest Entity [Line Items]
Transferred assets continue to be carried on the consolidated balance sheets	207,000	208,000
Assets associated with loan participation transactions
Variable Interest Entity [Line Items]
Transferred assets continue to be carried on the consolidated balance sheets	¥ 143,000	¥ 89,000

Summary of Noninterest Income (

Summary of Noninterest Income (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Fee and commission income		¥ 853,290	¥ 865,711	¥ 825,963
Foreign exchange gains (losses)-net	[1],[2]	93,577	91,793	69,453
Trading account gains (losses)-net	[3]	328,841	236,982	(42,481)
Investment gains (losses)-net:
Debt securities	[2]	(3,842)	7,757	59,517
Equity securities	[2]	(155,947)	289,400	273,753
Equity in earnings (losses) of equity method investees-net	[2]	29,172	24,342	26,785
Gains on disposal of premises and equipment	[2]	5,145	8,225	5,638
Other noninterest income	[3]	72,135	80,453	149,404
Total noninterest income		1,222,371	1,604,663	1,368,032
Securities related business
Disaggregation of Revenue [Line Items]
Fee and commission income	[4]	145,270	180,122	165,857
Banking
Disaggregation of Revenue [Line Items]
Fee and commission income	[3]	152,283	156,426	164,572
Correspondent clearing
Disaggregation of Revenue [Line Items]
Fee and commission income	[4]	110,382	110,054	108,368
Investment advisory, management and administrative service
Disaggregation of Revenue [Line Items]
Fee and commission income	[4]	97,852	100,765	79,426
Fiduciary and trust
Disaggregation of Revenue [Line Items]
Fee and commission income	[4]	124,843	121,808	108,931
Agency business
Disaggregation of Revenue [Line Items]
Fee and commission income	[4]	36,466	37,397	36,003
Guarantee related business
Disaggregation of Revenue [Line Items]
Fee and commission income	[2]	28,582	28,258	26,292
Financial service, other
Disaggregation of Revenue [Line Items]
Fee and commission income	[4]	157,612	130,881	136,514
Financial service
Disaggregation of Revenue [Line Items]
Fee and commission income		¥ 853,290	¥ 865,711	¥ 825,963
[1]	Amounts include realized and unrealized gains and losses on both derivative instruments and nonderivative instruments. Amounts on derivative instruments include gains and losses on forward foreign exchange contracts and currency options. Amounts on nonderivative instruments include translation gains and losses related to foreign currency-denominated debt securities reported as Trading securities.
[2]	These amounts are revenues from contracts that do not meet the scope of ASC 606.
[3]	Part of these amounts are considered to be revenues from contracts that are within the scope of ASC 606.
[4]	These amounts are revenues from contracts within the scope of ASC 606, "Revenue from contracts with customers " ("ASC 606").

Noninterest Income - Additional

Noninterest Income - Additional Information (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Other Revenues [Line Items]
Trust fees		¥ 51,000
Fees related to trust business		74,000
Trading account gains (losses)-net	[1]	328,841	¥ 236,982	¥ (42,481)
Other noninterest income	[1]	72,135	¥ 80,453	¥ 149,404
Revenue from contracts with customers ("ASC 606")
Other Revenues [Line Items]
Trading account gains (losses)-net		68,000
Other noninterest income		¥ 26,000
[1]	Part of these amounts are considered to be revenues from contracts that are within the scope of ASC 606.

Trading Account Gains and Los_3

Trading Account Gains and Losses (Net Trading Gains and Losses) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading account gains (losses)-net	[1]	¥ 328,841	¥ 236,982	¥ (42,481)
Foreign exchange gains (losses)-net	[2],[3]	93,577	91,793	69,453
Net trading gains (losses)		422,418	328,775	26,972
Interest rate contracts
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading account gains (losses)-net		127,242	(63,260)	(209,361)
Foreign exchange contracts
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading account gains (losses)-net	[4]	6,748	61,046	37,129
Equity-related contracts
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading account gains (losses)-net	[5]	37,875	(98,807)	1,777
Credit-related contracts
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading account gains (losses)-net	[6]	269	(2,076)	900
Other contracts
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading account gains (losses)-net		(1,455)	6,330	742
Trading securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading account gains (losses)-net		¥ 158,162	¥ 333,749	¥ 126,332
[1]	Part of these amounts are considered to be revenues from contracts that are within the scope of ASC 606.
[2]	Amounts include realized and unrealized gains and losses on both derivative instruments and nonderivative instruments. Amounts on derivative instruments include gains and losses on forward foreign exchange contracts and currency options. Amounts on nonderivative instruments include translation gains and losses related to foreign currency-denominated debt securities reported as Trading securities.
[3]	These amounts are revenues from contracts that do not meet the scope of ASC 606.
[4]	Amounts include gains and losses on currency swaps.
[5]	The net gain (loss) excluded from the assessment of the effectiveness of fair value hedges is included in the above table.
[6]	Amounts do not include the net loss of ¥7,594 million, ¥754 million and ¥736 million on the credit derivatives economically managing the credit risk of loans during the fiscal years ended March 31, 2017, 2018 and 2019, respectively. The net loss is recorded in Other noninterest expenses.

Trading Account Gains and Los_4

Trading Account Gains and Losses (Net Trading Gains and Losses) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Schedule of Trading Securities and Other Trading Assets [Line Items]
Gains (losses) recorded in income		¥ 169,943	¥ (93,321)	¥ (173,053)
Credit-related contracts
Schedule of Trading Securities and Other Trading Assets [Line Items]
Gains (losses) recorded in income	[1]	(467)	(2,830)	(6,694)
Credit-related contracts | Loans related to credit derivatives
Schedule of Trading Securities and Other Trading Assets [Line Items]
Gains (losses) recorded in income		¥ (736)	¥ (754)	¥ (7,594)
[1]	Amounts include the net loss of ¥7,594 million, ¥754 million and ¥736 million on the credit derivatives economically managing the credit risk of loans during the fiscal years ended March 31, 2017, 2018 and 2019, respectively.

Fair Value - Additional Informa

Fair Value - Additional Information (Detail) - JPY (¥) ¥ in Billions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Carrying amounts of other equity interests of which fair value is not readily determinable	¥ 212	¥ 267
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	21	21
Net unrealized gains (losses) resulting from changes in fair values of the notes	¥ (17)	(15)
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		10
Fair value of liabilities transferred into Level 3	¥ 7	1
Trading securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of assets transferred into Level 3		123
Fair value of assets transferred out of Level 3		241
Available-for-sale securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of assets transferred into Level 3	61	15
Fair value of assets transferred out of Level 3	¥ 42	¥ 46

Fair Value (Summary of Assets a

Fair Value (Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis, Including Fair Value Option Elected) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018
Assets:
Available-for-sale securities		¥ 18,133,916	¥ 23,665,628
Liabilities:
Long-term debt		2,433,294	1,955,636
Fair Value, Measurements, Recurring
Assets:
Equity securities with readily determinable fair values	[1]	3,768,000
Equity securities measured at net asset value	[2]	53,000
Other investments		35,000	38,000
Total assets measured at fair value		43,007,000	48,007,000
Liabilities:
Trading securities sold, not yet purchased		2,580,000	3,399,000
Long-term debt	[3]	2,433,000	1,956,000
Total liabilities measured at fair value		12,554,000	15,071,000
Fair Value, Measurements, Recurring | Trading Account Asset
Assets:
Securities measured at net asset value	[2]	631,000	705,000
Fair Value, Measurements, Recurring | Interest rate contracts
Assets:
Assets, derivatives		5,786,000	7,176,000
Liabilities:
Liabilities, derivatives		5,610,000	7,143,000
Fair Value, Measurements, Recurring | Foreign exchange contracts
Assets:
Assets, derivatives		1,959,000	2,697,000
Liabilities:
Liabilities, derivatives		1,758,000	2,382,000
Fair Value, Measurements, Recurring | Equity-related contracts
Assets:
Assets, derivatives		125,000	197,000
Liabilities:
Liabilities, derivatives		142,000	151,000
Fair Value, Measurements, Recurring | Credit-related contracts
Assets:
Assets, derivatives		18,000	18,000
Liabilities:
Liabilities, derivatives		17,000	21,000
Fair Value, Measurements, Recurring | Other contracts
Assets:
Assets, derivatives		16,000	23,000
Liabilities:
Liabilities, derivatives		14,000	19,000
Fair Value, Measurements, Recurring | Japanese government bonds
Assets:
Assets, trading securities	[4]	1,862,000	1,418,000
Available-for-sale securities		11,897,000	13,332,000
Fair Value, Measurements, Recurring | Japanese local government bonds
Assets:
Assets, trading securities	[4]	134,000	107,000
Available-for-sale securities		210,000	239,000
Fair Value, Measurements, Recurring | U.S. Treasury bonds and federal agency securities
Assets:
Assets, trading securities	[4]	1,207,000	2,651,000
Available-for-sale securities		1,009,000	686,000
Fair Value, Measurements, Recurring | Other foreign government bonds
Assets:
Assets, trading securities	[4]	2,970,000	2,162,000
Available-for-sale securities		1,342,000	1,058,000
Fair Value, Measurements, Recurring | Agency mortgage-backed securities
Assets:
Assets, trading securities	[4]	1,041,000	1,799,000
Available-for-sale securities		544,000	889,000
Fair Value, Measurements, Recurring | Residential mortgage-backed securities
Assets:
Assets, trading securities	[4]	11,000	12,000
Available-for-sale securities		101,000	119,000
Fair Value, Measurements, Recurring | Commercial mortgage-backed securities
Assets:
Available-for-sale securities		500,000	441,000
Fair Value, Measurements, Recurring | Certificates of deposit and commercial paper
Assets:
Assets, trading securities	[4]	1,047,000	643,000
Fair Value, Measurements, Recurring | Corporate bonds and other debt securities
Assets:
Assets, trading securities	[4]	2,886,000	3,030,000
Fair Value, Measurements, Recurring | Equity securities
Assets:
Assets, trading securities	[4]	1,325,000	1,665,000
Fair Value, Measurements, Recurring | Japanese corporate bonds and other debt securities
Assets:
Available-for-sale securities		1,749,000	1,990,000
Fair Value, Measurements, Recurring | Foreign corporate bonds and other debt securities
Assets:
Available-for-sale securities		781,000	879,000
Fair Value, Measurements, Recurring | Equity securities (marketable)
Assets:
Available-for-sale securities	[1]		4,033,000
Fair Value, Measurements, Recurring | Level 1
Assets:
Equity securities with readily determinable fair values	[1]	3,633,000
Total assets measured at fair value		22,753,000	24,698,000
Liabilities:
Trading securities sold, not yet purchased		2,380,000	2,777,000
Total liabilities measured at fair value		2,512,000	2,915,000
Fair Value, Measurements, Recurring | Level 1 | Interest rate contracts
Assets:
Assets, derivatives		36,000	39,000
Liabilities:
Liabilities, derivatives		38,000	42,000
Fair Value, Measurements, Recurring | Level 1 | Foreign exchange contracts
Assets:
Assets, derivatives		9,000	17,000
Liabilities:
Liabilities, derivatives		11,000	11,000
Fair Value, Measurements, Recurring | Level 1 | Equity-related contracts
Assets:
Assets, derivatives		58,000	82,000
Liabilities:
Liabilities, derivatives		82,000	81,000
Fair Value, Measurements, Recurring | Level 1 | Other contracts
Assets:
Assets, derivatives		2,000	6,000
Liabilities:
Liabilities, derivatives		1,000	4,000
Fair Value, Measurements, Recurring | Level 1 | Japanese government bonds
Assets:
Assets, trading securities	[4]	1,829,000	1,375,000
Available-for-sale securities		10,902,000	12,435,000
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury bonds and federal agency securities
Assets:
Assets, trading securities	[4]	1,069,000	2,442,000
Available-for-sale securities		1,009,000	686,000
Fair Value, Measurements, Recurring | Level 1 | Other foreign government bonds
Assets:
Assets, trading securities	[4]	2,417,000	1,682,000
Available-for-sale securities		456,000	355,000
Fair Value, Measurements, Recurring | Level 1 | Corporate bonds and other debt securities
Assets:
Assets, trading securities	[4]	36,000	25,000
Fair Value, Measurements, Recurring | Level 1 | Equity securities
Assets:
Assets, trading securities	[4]	1,297,000	1,642,000
Fair Value, Measurements, Recurring | Level 1 | Equity securities (marketable)
Assets:
Available-for-sale securities	[1]		3,912,000
Fair Value, Measurements, Recurring | Level 2
Assets:
Equity securities with readily determinable fair values	[1]	135,000
Total assets measured at fair value		17,629,000	20,703,000
Liabilities:
Trading securities sold, not yet purchased		199,000	618,000
Long-term debt	[3]	1,778,000	1,395,000
Total liabilities measured at fair value		9,358,000	11,552,000
Fair Value, Measurements, Recurring | Level 2 | Interest rate contracts
Assets:
Assets, derivatives		5,729,000	7,089,000
Liabilities:
Liabilities, derivatives		5,564,000	7,074,000
Fair Value, Measurements, Recurring | Level 2 | Foreign exchange contracts
Assets:
Assets, derivatives		1,927,000	2,667,000
Liabilities:
Liabilities, derivatives		1,746,000	2,370,000
Fair Value, Measurements, Recurring | Level 2 | Equity-related contracts
Assets:
Assets, derivatives		63,000	110,000
Liabilities:
Liabilities, derivatives		51,000	69,000
Fair Value, Measurements, Recurring | Level 2 | Credit-related contracts
Assets:
Assets, derivatives		16,000	16,000
Liabilities:
Liabilities, derivatives		16,000	20,000
Fair Value, Measurements, Recurring | Level 2 | Other contracts
Assets:
Assets, derivatives		4,000	8,000
Liabilities:
Liabilities, derivatives		4,000	6,000
Fair Value, Measurements, Recurring | Level 2 | Japanese government bonds
Assets:
Assets, trading securities	[4]	33,000	43,000
Available-for-sale securities		995,000	897,000
Fair Value, Measurements, Recurring | Level 2 | Japanese local government bonds
Assets:
Assets, trading securities	[4]	134,000	107,000
Available-for-sale securities		210,000	239,000
Fair Value, Measurements, Recurring | Level 2 | U.S. Treasury bonds and federal agency securities
Assets:
Assets, trading securities	[4]	138,000	209,000
Fair Value, Measurements, Recurring | Level 2 | Other foreign government bonds
Assets:
Assets, trading securities	[4]	553,000	480,000
Available-for-sale securities		886,000	703,000
Fair Value, Measurements, Recurring | Level 2 | Agency mortgage-backed securities
Assets:
Assets, trading securities	[4]	1,041,000	1,799,000
Available-for-sale securities		544,000	889,000
Fair Value, Measurements, Recurring | Level 2 | Residential mortgage-backed securities
Assets:
Available-for-sale securities		61,000	65,000
Fair Value, Measurements, Recurring | Level 2 | Certificates of deposit and commercial paper
Assets:
Assets, trading securities	[4]	1,047,000	643,000
Fair Value, Measurements, Recurring | Level 2 | Corporate bonds and other debt securities
Assets:
Assets, trading securities	[4]	1,806,000	1,992,000
Fair Value, Measurements, Recurring | Level 2 | Japanese corporate bonds and other debt securities
Assets:
Available-for-sale securities		1,629,000	1,827,000
Fair Value, Measurements, Recurring | Level 2 | Foreign corporate bonds and other debt securities
Assets:
Available-for-sale securities		678,000	799,000
Fair Value, Measurements, Recurring | Level 2 | Equity securities (marketable)
Assets:
Available-for-sale securities	[1]		121,000
Fair Value, Measurements, Recurring | Level 3
Assets:
Other investments		35,000	38,000
Total assets measured at fair value		1,941,000	1,901,000
Liabilities:
Trading securities sold, not yet purchased		1,000	4,000
Long-term debt	[3]	655,000	561,000
Total liabilities measured at fair value		684,000	604,000
Fair Value, Measurements, Recurring | Level 3 | Interest rate contracts
Assets:
Assets, derivatives		21,000	48,000
Liabilities:
Liabilities, derivatives		8,000	27,000
Fair Value, Measurements, Recurring | Level 3 | Foreign exchange contracts
Assets:
Assets, derivatives		23,000	13,000
Liabilities:
Liabilities, derivatives		1,000	1,000
Fair Value, Measurements, Recurring | Level 3 | Equity-related contracts
Assets:
Assets, derivatives		4,000	5,000
Liabilities:
Liabilities, derivatives		9,000	1,000
Fair Value, Measurements, Recurring | Level 3 | Credit-related contracts
Assets:
Assets, derivatives		2,000	2,000
Liabilities:
Liabilities, derivatives		1,000	1,000
Fair Value, Measurements, Recurring | Level 3 | Other contracts
Assets:
Assets, derivatives		10,000	9,000
Liabilities:
Liabilities, derivatives		9,000	9,000
Fair Value, Measurements, Recurring | Level 3 | Residential mortgage-backed securities
Assets:
Assets, trading securities	[4]	11,000	12,000
Available-for-sale securities		40,000	54,000
Fair Value, Measurements, Recurring | Level 3 | Commercial mortgage-backed securities
Assets:
Available-for-sale securities		500,000	441,000
Fair Value, Measurements, Recurring | Level 3 | Corporate bonds and other debt securities
Assets:
Assets, trading securities	[4]	1,044,000	1,013,000
Fair Value, Measurements, Recurring | Level 3 | Equity securities
Assets:
Assets, trading securities	[4]	28,000	23,000
Fair Value, Measurements, Recurring | Level 3 | Japanese corporate bonds and other debt securities
Assets:
Available-for-sale securities		120,000	163,000
Fair Value, Measurements, Recurring | Level 3 | Foreign corporate bonds and other debt securities
Assets:
Available-for-sale securities		¥ 103,000	¥ 80,000
[1]	The MHFG Group adopted ASU No.2016-01 on April 1, 2018. In connection with the adoption, equity securities are no longer classified as available-for-sale securities. See Note 2 "Recently issued accounting pronouncements" for further details.
[2]	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, 2018 and 2019 were ¥31 billion and ¥37 billion, respectively.
[3]	Amounts represent items for which the Group elected the fair value option or for which it applied the practicability exception.
[4]	Trading securities include foreign currency denominated securities for which the MHFG Group elected the fair value option.

Fair Value (Summary of Assets_2

Fair Value (Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis, Including Fair Value Option Elected) (Parenthetical) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2019	Mar. 31, 2018
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unfunded commitments	¥ 37	¥ 31

Fair Value (Reconciliation for

Fair Value (Reconciliation for All Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3)) (Detail) - JPY (¥) ¥ in Billions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Other investments
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		¥ 38	¥ 37
Gains (losses) in Earnings	[1]	5
Purchases		13	14
Sales		(6)	(3)
Issuances		0	0
Settlements		(15)	(10)
Ending Balance		35	38
Change in unrealized gain (losses) still held	[2]	(2)
Trading securities sold, not yet purchased
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		4
Gains (losses) in Earnings	[3]	1
Purchases		(35)	(146)
Sales		33	150
Ending Balance		1	4
Long-term debt
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		561	593
Gains (losses) in Earnings	[4]	(6)	3
Gains (losses) in OCI	[5]	10
Transfers into Level 3		7	1
Transfers out of level 3			(10)
Issuances		192	151
Settlements		(101)	(171)
Ending Balance		655	561
Change in unrealized gain (losses) still held	[2]	5	5
Trading securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers into Level 3			123
Transfers out of level 3			(241)
Trading securities | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		12	15
Issuances		0	0
Settlements		(1)	(3)
Ending Balance		11	12
Trading securities | Corporate bonds and other debt securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		1,013	1,052
Gains (losses) in Earnings	[3]	1	(20)
Transfers into Level 3			123
Transfers out of level 3			(241)
Purchases		762	1,082
Sales		(378)	(631)
Issuances		0	0
Settlements		(354)	(352)
Ending Balance		1,044	1,013
Change in unrealized gain (losses) still held	[2]	8	(19)
Trading securities | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		23	23
Gains (losses) in Earnings	[3]	1	(1)
Purchases		7	2
Sales		(3)	(1)
Issuances		0	0
Ending Balance		28	23
Change in unrealized gain (losses) still held	[2]	(1)
Derivative financial instruments assets | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[6]	21	26
Gains (losses) in Earnings	[3],[6]	(11)	(6)
Issuances	[6]	0	0
Settlements	[6]	3	1
Ending Balance	[6]	13	21
Change in unrealized gain (losses) still held	[2],[6]	(5)	(1)
Derivative financial instruments assets | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[6]	12	8
Gains (losses) in Earnings	[3],[6]	15	2
Issuances	[6]	0	0
Settlements	[6]	(5)	2
Ending Balance	[6]	22	12
Change in unrealized gain (losses) still held	[2],[6]	14	5
Derivative financial instruments assets | Equity-related contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[6]	4	(25)
Gains (losses) in Earnings	[3],[6]	(15)	1
Issuances	[6]	0	0
Settlements	[6]	6	28
Ending Balance	[6]	(5)	4
Change in unrealized gain (losses) still held	[2],[6]	3	12
Derivative financial instruments assets | Other contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Gains (losses) in Earnings	[3],[6]	1	(1)
Issuances	[6]	0	0
Settlements	[6]		1
Ending Balance	[6]	1
Change in unrealized gain (losses) still held	[2],[6]	1
Derivative financial instruments assets | Credit Related Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[6]	1
Gains (losses) in Earnings	[3],[6]	(2)
Issuances	[6]	0	0
Settlements	[6]	2	1
Ending Balance	[6]	1	1
Change in unrealized gain (losses) still held	[2],[6]	1
Available-for-sale securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers into Level 3		61	15
Transfers out of level 3		(42)	(46)
Available-for-sale securities | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		54	77
Purchases			3
Sales			(6)
Issuances		0	0
Settlements		(14)	(20)
Ending Balance		40	54
Available-for-sale securities | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		441	224
Gains (losses) in OCI	[5]	1	3
Purchases		144	286
Sales		(72)	(69)
Issuances		0	0
Settlements		(14)	(3)
Ending Balance		500	441
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		163	174
Gains (losses) in Earnings	[1]	37	11
Gains (losses) in OCI	[5]	(33)	(10)
Purchases		29	17
Sales		(7)
Issuances		0	0
Settlements		(69)	(29)
Ending Balance		120	163
Change in unrealized gain (losses) still held	[2]	19	11
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		80	110
Gains (losses) in OCI	[5]	(1)	(1)
Transfers into Level 3		61	15
Transfers out of level 3		(42)	(46)
Purchases		27	2
Issuances		0	0
Settlements		(22)
Ending Balance		¥ 103	¥ 80
[1]	Gains (losses) in Earnings are reported in Investment gains (losses)-net.
[2]	Amounts represent total gains or losses recognized in earnings during the period. These gains or losses were attributable to the change in fair value relating to assets and liabilities classified as Level 3 that were still held at March 31, 2018 and 2019.
[3]	Gains (losses) in Earnings are reported in Trading account gains (losses)-net, Foreign exchange gains (losses)-net or Other noninterest income (expenses).
[4]	Gains (losses) in Earnings are reported in Other noninterest income (expenses).
[5]	Gains (losses) in OCI are reported in Other comprehensive income (loss).
[6]	Total Level 3 derivative exposures have been netted on the table for presentation purposes only.

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		Mar. 31, 2019JPY (¥)BasisPoint		Mar. 31, 2018JPY (¥)BasisPoint
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt | ¥		¥ 2,433,294		¥ 1,955,636
Available For Sale And Trading Securities | Residential mortgage-backed securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities | ¥		51,000		66,000
Available For Sale And Trading Securities | Commercial mortgage-backed securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities | ¥		500,000		441,000
Available For Sale And Trading Securities | Corporate bonds and other debt securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities | ¥		1,267,000		1,256,000
Derivative Financial Instruments | Interest rate contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments | ¥		13,000		21,000
Derivative Financial Instruments | Foreign exchange contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments | ¥		22,000		12,000
Derivative Financial Instruments | Equity-related contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments | ¥		(5,000)		4,000
Derivative Financial Instruments | Credit-related contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments | ¥		1,000		1,000
Long-term debt
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt | ¥		¥ 655,000		¥ 561,000
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		0.04		0.03
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]	0.22		0.26
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]	0.02		0.01
Minimum | Measurement Input, Default Rate [Member] | Derivative Financial Instruments | Interest rate contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[2],[3]	0		0
Minimum | Measurement Input, Default Rate [Member] | Derivative Financial Instruments | Foreign exchange contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[2],[3]	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		1		1
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]	0.69		0.60
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		18		17
Minimum | Measurement Input, Discount Rate [Member] | Available For Sale And Trading Securities | Commercial mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		9		9
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		48	[1]	12	[4]
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	[4]	4		5
Minimum | Measurement Input, IR - IR correlation [Member] | Derivative Financial Instruments | Interest rate contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[2]	0.23		0.23
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]	0.23		0.23
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]	0.09		0.16
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]	0.09		0.09
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]	0.63		0.61
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]	0.63		0.61
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]	0.25		0.25
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]	0.25		0.25
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]	0.05		0.12
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]	0.05		0.13
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]	0.29		0.27
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]	0.20		0.28
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]	0.55		0.55
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]	0.40
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]	0.12		0.24
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		0.19		0.17
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]	0.22		0.37
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		0.01		0.01
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]	0.02		0.02
Maximum | Measurement Input, Default Rate [Member] | Derivative Financial Instruments | Interest rate contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[2],[3]	0.63		0.63
Maximum | Measurement Input, Default Rate [Member] | Derivative Financial Instruments | Foreign exchange contracts | Internal Valuation Model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivatives financial instruments	[2],[3]	0.63		0.63
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]	0.05		0.03
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]	0.04		0.02
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		1		1
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]	0.69		0.69
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		170		170
Maximum | Measurement Input, Discount Rate [Member] | Available For Sale And Trading Securities | Commercial mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities		161		141
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		1,173	[1]	1,165	[4]
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	[4]	1,063		1,064
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]	1		1
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]	1		1
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]	0.55		0.53
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]	0.55		0.53
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]	0.63		0.61
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]	0.63		0.61
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]	0.25		0.25
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]	0.25		0.25
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]	0.36		0.41
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]	0.49		0.56
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]	1		1
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]	1		1
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]	0.88		0.70
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]	1
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]	1		1
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	[5]	0.08		0.07
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],[5]	0.22		0.36
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	[5]	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],[5]	0.02		0.02
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	[5]	1		1
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],[5]	0.69		0.68
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	[5]	51		50
Weighted Average | Measurement Input, Discount Rate [Member] | Available For Sale And Trading Securities | Commercial mortgage-backed securities | Discounted Cash Flows Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading securities	[5]	24		28
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	[5]	134	[1]	115	[4]
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	[4],[5]	295		379
[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 represents the counterparty default rate derived from the MHFG Group's own internal credit analyses.
[4]	This input is mainly used for determining the fair values of Japanese corporate bonds and foreign corporate bonds.
[5]	Weighted averages are calculated by weighting each input by the relative fair value of the respective financial instruments.

Fair Value (Summary of Assets_3

Fair Value (Summary of Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis) (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2019	Mar. 31, 2018
Assets:
Equity securities	¥ 212,270
Fair Value, Measurements, Nonrecurring
Assets:
Loans	125,000	¥ 113,000
Loans held-for-sale	3,000	60,000
Equity securities	1,000	1,000
Other investments	98,000
Premises and equipment-net	9,000
Total assets measured at fair value	236,000	174,000
Fair Value, Measurements, Nonrecurring | Aggregate cost
Assets:
Loans	177,000	164,000
Loans held-for-sale	3,000	74,000
Equity securities	1,000	3,000
Other investments	104,000
Premises and equipment-net	34,000	4,000
Intangible assets	1,000
Total assets measured at fair value	320,000	245,000
Fair Value, Measurements, Nonrecurring | Level 1
Assets:
Other investments	98,000
Total assets measured at fair value	98,000
Fair Value, Measurements, Nonrecurring | Level 2
Assets:
Loans	41,000
Loans held-for-sale	3,000	60,000
Premises and equipment-net	4,000
Total assets measured at fair value	48,000	60,000
Fair Value, Measurements, Nonrecurring | Level 3
Assets:
Loans	84,000	113,000
Equity securities	1,000	1,000
Premises and equipment-net	5,000
Total assets measured at fair value	¥ 90,000	¥ 114,000

Fair Value (Carrying Amounts an

Fair Value (Carrying Amounts and Fair Values of Certain Financial Instruments, Excluding Financial Instruments Carried at Fair Value on a Recurring Basis and Those outside Scope of ASC 825) (Detail) - JPY (¥) ¥ in Millions		Mar. 31, 2019	Mar. 31, 2018
Financial liabilities:
Long-term debt		¥ 2,433,294	¥ 1,955,636
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		62,012,000	61,381,000
Investments		1,604,000	2,518,000
Loans, net of allowance for loan losses	[1]	82,382,000	83,088,000
Financial liabilities:
Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions		44,918,000	43,921,000
Interest-bearing deposits		112,658,000	113,558,000
Due to trust accounts		312,000	3,993,000
Other short-term borrowings		1,995,000	1,688,000
Long-term debt		9,096,000	10,970,000
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		62,012,000	61,381,000
Investments		1,609,000	2,522,000
Loans, net of allowance for loan losses	[1]	83,490,000	84,041,000
Financial liabilities:
Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions		44,918,000	43,921,000
Interest-bearing deposits		112,655,000	113,540,000
Due to trust accounts		312,000	3,993,000
Other short-term borrowings		1,995,000	1,688,000
Long-term debt		9,178,000	10,995,000
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		873,000	1,206,000
Investments		1,140,000	1,984,000
Financial liabilities:
Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions		24,983,000	22,898,000
Interest-bearing deposits		55,542,000	61,719,000
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		61,139,000	60,175,000
Investments		469,000	538,000
Financial liabilities:
Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions		19,935,000	21,023,000
Interest-bearing deposits		57,113,000	51,821,000
Due to trust accounts		312,000	3,993,000
Other short-term borrowings		1,995,000	1,688,000
Long-term debt		8,336,000	10,098,000
Estimated fair value | Level 3
Financial assets:
Loans, net of allowance for loan losses	[1]	83,490,000	84,041,000
Financial liabilities:
Long-term debt		¥ 842,000	¥ 897,000
[1]	Loans, net of allowance for loan losses include items measured at fair value on a nonrecurring basis.

Offsetting of Financial Asset_3

Offsetting of Financial Assets and Financial Liabilities (Information of Offsetting of Financial Assets and Financial Liabilities) (Detail) - JPY (¥) ¥ in Billions		Mar. 31, 2019	Mar. 31, 2018
Offsetting Financial Assets And Financial Liabilities [Line Items]
Derivative assets, Gross amounts recognized	[1]	¥ 7,403	¥ 9,341
Derivative assets, Gross amounts offset on the balance sheet	[1]	0	0
Derivative assets, Net amounts presented on the balance sheet	[1],[2]	7,403	9,341
Derivative assets, Amounts not offset on the balance sheet, Financial instruments	[1],[3],[4]	(5,903)	(7,751)
Derivative assets, Amounts not offset on the balance sheet, Cash collateral	[1],[3]	(528)	(520)
Derivative assets, Net amounts	[1]	972	1,070
Receivables under resale agreements, Gross amounts recognized	[1]	12,589	7,804
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]	12,589	7,804
Receivables under resale agreements, Amounts not offset on the balance sheet, Financial instruments	[1],[3],[4]	(12,579)	(7,763)
Receivables under resale agreements, Amounts not offset on the balance sheet, Cash collateral	[1],[3]	0	0
Receivables under resale agreements, Net amounts	[1]	10	41
Receivables under securities borrowing transactions, Gross amounts recognized	[1]	1,921	3,904
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]	1,921	3,904
Receivables under securities borrowing transactions, Amounts not offset on the balance sheet, Financial instruments	[1],[3],[4]	(1,894)	(3,874)
Receivables under securities borrowing transactions, Amounts not offset on the balance sheet, Cash collateral	[1],[3]	0	0
Receivables under securities borrowing transactions, Net amounts	[1]	27	30
Financial assets, Gross amounts recognized, Total	[1]	21,913	21,049
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]	21,913	21,049
Financial assets, Amounts not offset on the balance sheet, Financial instruments, Total	[1],[3],[4]	(20,376)	(19,388)
Financial assets, Amounts not offset on the balance sheet, Cash collateral, Total	[1],[3]	(528)	(520)
Financial assets, Net amounts, Total	[1]	1,009	1,141
Derivative liabilities, Gross amounts recognized	[1]	6,978	9,013
Derivative liabilities, Gross amounts offset on the balance sheet	[1]	0	0
Derivative liabilities, Net amounts presented on the balance sheet	[1],[2]	6,978	9,013
Derivative liabilities, Amounts not offset on the balance sheet, Financial instruments	[1],[3],[4]	(5,766)	(7,758)
Derivative liabilities, Amounts not offset on the balance sheet, Cash collateral	[1],[3]	(769)	(884)
Derivative liabilities, Net amounts	[1]	443	371
Payables under repurchase agreements, Gross amounts recognized	[1]	14,312	15,964
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]	14,312	15,964
Payables under repurchase agreements, Amounts not offset on the balance sheet, Financial instruments	[1],[3],[4]	(14,309)	(15,847)
Payables under repurchase agreements, Amounts not offset on the balance sheet, Cash collateral	[1],[3]	0	0
Payables under repurchase agreements, Net amounts	[1]	3	117
Payables under securities lending transactions, Gross amounts recognized	[1]	932	1,181
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]	932	1,181
Payables under securities lending transactions, Amounts not offset on the balance sheet, Financial instruments	[1],[3],[4]	(931)	(1,179)
Payables under securities lending transactions, Amounts not offset on the balance sheet, Cash collateral	[1],[3]	0	0
Payables under securities lending transactions, Net amounts	[1]	1	2
Financial liabilities, Gross amounts recognized, Total	[1]	22,222	26,158
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]	22,222	26,158
Financial liabilities, Amounts not offset on the balance sheet, Financial instruments, Total	[1],[3],[4]	(21,006)	(24,784)
Financial liabilities, Amounts not offset on the balance sheet, Cash collateral, Total	[1],[3]	(769)	(884)
Financial liabilities, Net amounts, Total	[1]	¥ 447	¥ 490
[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]	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.

Repurchase Agreements and Sec_3

Repurchase Agreements and Securities Lending Transactions Accounted for as Secured Borrowings (Gross Amounts of Liabilities by Remaining Contractual Maturity) (Detail) - JPY (¥) ¥ in Billions		Mar. 31, 2019	Mar. 31, 2018
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	[1]	¥ 14,640	¥ 16,657
Securities lending transactions	[1]	1,798	1,833
Total		16,438	18,490
Overnight and continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements		2,596	255
Securities lending transactions		1,012	1,270
Total		3,608	1,525
Up to 30 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements		8,537	11,669
Securities lending transactions		473	355
Total		9,010	12,024
31 to 90 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements		2,403	3,676
Total		2,403	3,676
Greater than 90 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements		1,104	1,057
Securities lending transactions		313	208
Total		¥ 1,417	¥ 1,265
[1]	Amounts exceeded the gross amounts recognized in Note 29 "Offsetting of financial assets and financial liabilities" by ¥1,345 billion and ¥1,194 billion, at March 31, 2018 and 2019, respectively, which excluded the amounts relating to master netting agreements or similar agreements where the MHFG Group did not have the legal right of set-off or where uncertainty exists as to the enforceability.

Repurchase Agreements and Sec_4

Repurchase Agreements and Securities Lending Transactions Accounted for as Secured Borrowings (Gross Amounts of Liabilities by Class of Underlying Collateral) (Detail) - JPY (¥) ¥ in Billions		Mar. 31, 2019	Mar. 31, 2018
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	[1]	¥ 14,640	¥ 16,657
Securities lending transactions	[1]	1,798	1,833
Japanese government bonds and Japanese local government bonds
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements		2,118	1,358
Securities lending transactions		430	592
Foreign government bonds and foreign agency mortgage-backed securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements		11,613	14,426
Securities lending transactions		396	303
Commercial Paper and Corporate Bonds
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements		223	328
Securities lending transactions		52	48
Equity Securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements		492	406
Securities lending transactions		902	869
Other securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements		194	139
Securities lending transactions		¥ 18	¥ 21
[1]	Amounts exceeded the gross amounts recognized in Note 29 "Offsetting of financial assets and financial liabilities" by ¥1,345 billion and ¥1,194 billion, at March 31, 2018 and 2019, respectively, which excluded the amounts relating to master netting agreements or similar agreements where the MHFG Group did not have the legal right of set-off or where uncertainty exists as to the enforceability.

Repurchase Agreements and Sec_5

Repurchase Agreements and Securities Lending Transactions Accounted for as Secured Borrowings (Gross Amounts of Liabilities by Class of Underlying Collateral) (Parenthetical) (Detail) - JPY (¥) ¥ in Billions	Mar. 31, 2019	Mar. 31, 2018
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Amounts exceeded the gross amounts recognized in offsetting of financial assets and financial liabilities	¥ 1,194	¥ 1,345

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - Loans	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Related Party Transaction [Line Items]
Number of loans impaired	0	0

Business Segment Information -

Business Segment Information - Additional Information (Detail)	12 Months Ended
	Mar. 31, 2018Segment
Segment Reporting Information [Line Items]
Number of operating segments	5

Business Segment Information (R

Business Segment Information (Reportable Segment Information Derived from Internal Management Reporting Systems, on Basis of Japanese GAAP) (Detail) - JPY (¥) ¥ in Billions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018		Mar. 31, 2017
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits + Net gains (losses) related to ETFs and others	[1]	¥ 1,827.7	¥ 1,995.6		¥ 2,129.2
General and administrative expenses	[2]	1,440.6	1,444.2		1,410.3
Equity in earnings (losses) of equity method investees-net	[2]	51.2	21.5		18.9
Amortization of goodwill and others	[2]	13.6	13.9		10.2
Others	[2]	(16.3)	(21)		(27.7)
Net business profits (losses) (2) + Net gains (losses) related to ETFs and others	[2]	408.4	538	[3]	699.9	[3]
Fixed assets	[2],[4]	1,657.2
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]	707.2	726.9		716.7
General and administrative expenses	[2]	713.7	724.8		719.3
Equity in earnings (losses) of equity method investees-net	[2]	18.1	12.7		14.9
Amortization of goodwill and others	[2]	0.4	0.4		0.4
Net business profits (losses) (2) + Net gains (losses) related to ETFs and others	[2]	11.2	14.4	[3]	11.9	[3]
Fixed assets	[2],[4]	499.3
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]	473.8	431.4		438.3
General and administrative expenses	[2]	198.2	202.5		199.9
Equity in earnings (losses) of equity method investees-net	[2]	0.9	1		1
Amortization of goodwill and others	[2]	0.4	0.4		0.4
Net business profits (losses) (2) + Net gains (losses) related to ETFs and others	[2]	276.1	229.5	[3]	239	[3]
Fixed assets	[2],[4]	225.8
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]	416.1	340.7		339.4
General and administrative expenses	[2]	251.8	250.9		239.2
Equity in earnings (losses) of equity method investees-net	[2]	7.3	2.3		0.9
Amortization of goodwill and others	[2]	0.4	0.4		0.4
Net business profits (losses) (2) + Net gains (losses) related to ETFs and others	[2]	171.2	91.7	[3]	100.7	[3]
Fixed assets	[2],[4]	176.9
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]	192	389.2		549.3
General and administrative expenses	[2]	203.3	201.2		191.2
Amortization of goodwill and others	[2]	2.3	2.3		2.3
Net business profits (losses) (2) + Net gains (losses) related to ETFs and others	[2]	(13.6)	185.7	[3]	355.8	[3]
Fixed assets	[2],[4]	92.6
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]	49.7	50.1		48.8
General and administrative expenses	[2]	27.3	27.6		29.3
Equity in earnings (losses) of equity method investees-net	[2]	1.3	2.9		0.5
Amortization of goodwill and others	[2]	8	8		4
Net business profits (losses) (2) + Net gains (losses) related to ETFs and others	[2]	15.7	17.4	[3]	16	[3]
Fixed assets	[2],[4]	0.1
Others
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits + Net gains (losses) related to ETFs and others	[1],[5]	(11.1)	57.3		36.7
General and administrative expenses	[2],[5]	46.3	37.2		31.4
Equity in earnings (losses) of equity method investees-net	[2],[5]	23.6	2.6		1.6
Amortization of goodwill and others	[2],[5]	2.1	2.4		2.7
Others	[2],[5]	(16.3)	(21)		(27.7)
Net business profits (losses) (2) + Net gains (losses) related to ETFs and others	[2],[5]	(52.2)	¥ (0.7)	[3]	¥ (23.5)	[3]
Fixed assets	[2],[4],[5]	¥ 662.5
[1]	"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 and net gains (losses) on operating investment securities of MHSC on its consolidated basis. For the fiscal years ended March 31, 2017, 2018 and 2019, net gains related to ETFs and others amounted to ¥36.5 billion, ¥80.2 billion and ¥15.0 billion, respectively, of which ¥32.6 billion, ¥70.1 billion and ¥7.3 billion, respectively, are included in "Global Markets Company".
[2]	Beginning on April 1, 2018, new allocation methods for income and expense transactions between each segment and "Others" have been applied. In connection with the use of the new allocation methods, the presentation of "Net business profits" has changed to "Net business profits (losses) + Net gains (losses) related to ETFs and others". Before the change, "Net gains (losses) related to ETFs and others" were included in "Gross profits" of each segment and eliminated in "Others". In addition, "Amortization of goodwill and others" has been presented as a new item. Figures for the fiscal years ended March 31, 2017 and 2018 have been restated for the new allocation methods. These changes more appropriately reflect the performance of each of the operating segments in accordance with internal managerial accounting rules and practices. Furthermore, income and expense of foreign branches of MHBK and foreign subsidiaries with functional currency other than Japanese Yen have been translated for purposes of segment reporting using the budgeted foreign currency rates. Prior period comparative amounts for these foreign currency income and expense have been translated using current period budgeted foreign currency rates.
[3]	Net business profits 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 plus equity in earnings (losses) of equity method investees-net and others. Measurement of net business profits is required for regulatory reporting to the Financial Services Agency.
[4]	"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, and Intangible assets. The above tables do 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. "Fixed assets" has been allocated to each segment starting in the fiscal year ended March 31, 2019 to enhance management's analysis of the Group's operations. "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 the in-house company segments using a reasonable allocation criteria.
[5]	"Others" includes items which should be eliminated as internal transactions between each segment on a consolidated basis.

Business Segment Information _2

Business Segment Information (Reportable Segment Information Derived from Internal Management Reporting Systems, on Basis of Japanese GAAP) (Parenthetical) (Detail) - JPY (¥) ¥ in Billions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits and net gains (losses) related to ETFs and others	[1]	¥ 1,827.7	¥ 1,995.6	¥ 2,129.2
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		15	80.2	36.5
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		¥ 7.3	¥ 70.1	¥ 32.6
[1]	"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 and net gains (losses) on operating investment securities of MHSC on its consolidated basis. For the fiscal years ended March 31, 2017, 2018 and 2019, net gains related to ETFs and others amounted to ¥36.5 billion, ¥80.2 billion and ¥15.0 billion, respectively, of which ¥32.6 billion, ¥70.1 billion and ¥7.3 billion, respectively, are included in "Global Markets Company".

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 Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
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	¥ 408,400	¥ 538,000	¥ 699,900
Adjustment to reconcile management reporting to Japanese GAAP:
General and administrative expenses (non-recurring losses)	23,300	(30,900)	(46,700)
Expenses related to portfolio problems (including reversal of (provision for) general reserve for losses on loans)	(30,700)	(17,000)	(80,200)
Gains on reversal of reserves for possible losses on loans, and others	11,200	173,300	32,700
Net gains (losses) related to stocks - Net gains (losses) related to ETFs and others	259,900	191,900	205,700
Net extraordinary gains (losses)	(497,900)	17,500	46,700
Others	(57,900)	(72,800)	(73,900)
Income before income tax expense under Japanese GAAP	116,300	800,000	784,200
Adjustment to reconcile Japanese GAAP to U.S. GAAP:
Derivative financial instruments and hedging activities	45,300	(110,200)	(221,900)
Investments	(273,300)	98,100	(115,900)
Loans	(11,900)	(2,400)	2,500
Allowances for loan losses and off-balance-sheet instruments	(5,800)	6,800	(13,800)
Premises and equipment	303,600	35,400	28,600
Land revaluation	10,200	3,400	4,500
Business combinations	(12,800)	15,600	14,800
Pension liabilities	(32,200)	(4,400)	33,800
Consolidation of variable interest entities	(39,000)	2,700	1,600
Foreign currency translation	1,700	12,100	(6,200)
Others	(17,000)	(17,800)	(31,800)
Income before income tax expense	¥ 85,060	¥ 839,298	¥ 480,375

Business Segment Information _4

Business Segment Information (Reconciliation of Assets from Segment to Consolidated) (Detail) ¥ in Billions	12 Months Ended
	Mar. 31, 2019JPY (¥)
Schedule Of Assets By Segment [Line Items]
Fixed assets	¥ 1,657.2	[1],[2]
U.S. GAAP adjustments	413.1
Premises and equipment-net, Goodwill, and Intangible assets	¥ 2,070.3
[1]	"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, and Intangible assets. The above tables do 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. "Fixed assets" has been allocated to each segment starting in the fiscal year ended March 31, 2019 to enhance management's analysis of the Group's operations. "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 the in-house company segments using a reasonable allocation criteria.
[2]	Beginning on April 1, 2018, new allocation methods for income and expense transactions between each segment and "Others" have been applied. In connection with the use of the new allocation methods, the presentation of "Net business profits" has changed to "Net business profits (losses) + Net gains (losses) related to ETFs and others". Before the change, "Net gains (losses) related to ETFs and others" were included in "Gross profits" of each segment and eliminated in "Others". In addition, "Amortization of goodwill and others" has been presented as a new item. Figures for the fiscal years ended March 31, 2017 and 2018 have been restated for the new allocation methods. These changes more appropriately reflect the performance of each of the operating segments in accordance with internal managerial accounting rules and practices. Furthermore, income and expense of foreign branches of MHBK and foreign subsidiaries with functional currency other than Japanese Yen have been translated for purposes of segment reporting using the budgeted foreign currency rates. Prior period comparative amounts for these foreign currency income and expense have been translated using current period budgeted foreign currency rates.

Foreign Activities (Consolidate

Foreign Activities (Consolidated Income Statement and Total Assets Information by Major Geographic Area) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Total revenue	[1]	¥ 3,429,800	¥ 3,366,500	¥ 2,877,100
Total expenses	[2]	3,344,700	2,527,200	2,396,700
Income before income tax expense		85,060	839,298	480,375
Net income		75,725	601,694	389,131
Total assets at end of fiscal year		197,611,195	204,255,642	200,456,300
Japan
Segment Reporting Information [Line Items]
Total revenue	[1]	1,705,500	2,002,400	1,748,300
Total expenses	[2]	2,082,600	1,582,500	1,712,300
Income before income tax expense		(377,100)	419,900	36,000
Net income		(331,400)	231,300	5,700
Total assets at end of fiscal year		133,443,500	142,587,800	138,832,300
United States of America
Segment Reporting Information [Line Items]
Total revenue	[1]	792,100	654,900	500,300
Total expenses	[2]	696,500	478,800	303,200
Income before income tax expense		95,600	176,100	197,100
Net income		85,300	152,700	167,600
Total assets at end of fiscal year		25,913,500	28,135,900	30,262,000
Others
Segment Reporting Information [Line Items]
Total revenue	[1]	66,000	64,000	70,300
Total expenses	[2]	46,100	38,500	29,100
Income before income tax expense		19,900	25,500	41,200
Net income		17,000	23,700	38,800
Total assets at end of fiscal year		4,824,700	4,380,400	4,203,300
Europe
Segment Reporting Information [Line Items]
Total revenue	[1]	249,700	197,400	190,700
Total expenses	[2]	203,200	172,600	136,200
Income before income tax expense		46,500	24,800	54,500
Net income		34,600	21,300	39,500
Total assets at end of fiscal year		15,322,500	11,677,800	10,629,100
Asia/Oceania excluding Japan, and others
Segment Reporting Information [Line Items]
Total revenue	[1]	616,500	447,800	367,500
Total expenses	[2]	316,300	254,800	215,900
Income before income tax expense		300,200	193,000	151,600
Net income		270,200	172,700	137,500
Total assets at end of fiscal year		¥ 18,107,000	¥ 17,473,700	¥ 16,529,600
[1]	Total revenue is comprised of Interest and dividend income and Noninterest income.
[2]	Total expenses are comprised of Interest expense, Provision (credit) for loan losses and Noninterest expenses.

Mizuho Financial Group, Inc.,_3

Mizuho Financial Group, Inc., Parent Company (Condensed Balance Sheets) (Detail) - JPY (¥) ¥ in Millions	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Assets:
Cash and due from banks	¥ 1,404,008	¥ 1,685,835
Interest-bearing deposits in other banks	44,268,731	46,485,086
Trading account assets	21,018,230	24,302,543
Other	5,276,004	5,731,634
Total	197,611,195	204,255,642	¥ 200,456,300
Liabilities and shareholders' equity:
Long-term debt	11,529,400	12,955,230
Other liabilities	5,932,706	4,705,595
Shareholders' equity	8,726,519	8,868,421
Total liabilities and equity	197,611,195	204,255,642
Parent Company
Assets:
Cash and due from banks	99,209	22,264
Interest-bearing deposits in other banks	1,158	1,227
Trading account assets		176,593
Investments in subsidiaries and affiliated companies	9,317,387	9,501,633
Long-term loans receivable from subsidiaries	5,110,248	3,969,015
Other	351,951	344,065
Total	14,879,953	14,014,797
Liabilities and shareholders' equity:
Short-term borrowings	945,505	1,083,135
Long-term debt	5,145,286	3,969,015
Other liabilities	62,643	94,226
Shareholders' equity	8,726,519	8,868,421
Total liabilities and equity	¥ 14,879,953	¥ 14,014,797

Mizuho Financial Group, Inc.,_4

Mizuho Financial Group, Inc., Parent Company (Condensed Statements of Income) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Income:
Total	[1]	¥ 3,429,800	¥ 3,366,500	¥ 2,877,100
Expenses:
Interest expense		1,313,476	889,936	601,712
Equity in undistributed net income (loss) of subsidiaries	[2]	29,172	24,342	26,785
Income tax expense (benefit)		9,335	237,604	91,244
Net income		84,471	577,608	362,440
Parent Company
Income:
Management fees from subsidiaries		39,292	47,945	48,594
Interest income on loans and discounts		106,920	68,869	39,359
Other income		9,575	52,672	21,054
Total		446,903	425,530	437,155
Expenses:
Operating expenses		40,680	38,661	38,927
Interest expense		110,861	74,227	48,594
Other expense		59,049	28,123	14,608
Total		210,590	141,011	102,129
Equity in undistributed net income (loss) of subsidiaries		(173,142)	309,210	32,595
Income before income tax expense		63,171	593,729	367,621
Income tax expense (benefit)		(21,300)	16,121	5,181
Net income		84,471	577,608	362,440
Parent Company | Banking Subsidiary
Income:
Banking subsidiaries		267,724	227,057	300,530
Parent Company | Non Banking Subsidiaries And Affiliated Companies
Income:
Banking subsidiaries		¥ 23,392	¥ 28,987	¥ 27,618
[1]	Total revenue is comprised of Interest and dividend income and Noninterest income.
[2]	These amounts are revenues from contracts that do not meet the scope of ASC 606.

Mizuho Financial Group, Inc.,_5

Mizuho Financial Group, Inc., Parent Company (Condensed Statements of Cash Flows) (Detail) - JPY (¥) ¥ in Millions		12 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income		¥ 84,471	¥ 577,608	¥ 362,440
Net cash provided by (used in) operating activities		661,019	(161,076)	1,209,127
Cash flows from investing activities:
Proceeds from sales of Equity securities	[1]	3,973,437
Net change in loans		(3,852,757)	(1,971,210)	(5,606,627)
Purchases of premises and equipment		(157,714)	(292,201)	(430,913)
Net cash used in investing activities		(6,773,772)	(3,624,755)	(2,112,331)
Cash flows from financing activities:
Net change in short-term borrowings		270,560	257,774	(589,512)
Proceeds from issuance of long-term debt		1,659,412	1,956,007	4,496,041
Proceeds from issuance of common stock		3	3	6
Purchases of treasury stock		(2,124)	(1,611)	(1,435)
Dividends paid		(190,413)	(190,382)	(190,031)
Net cash provided by financing activities		3,408,385	4,652,627	11,869,753
Effect of exchange rate changes on cash and cash equivalents		206,186	(282,846)	(29,583)
Net increase (decrease) in cash and cash equivalents		(2,498,182)	583,950	10,936,966
Cash and cash equivalents at beginning of fiscal year		48,170,921	47,586,971	36,650,005
Cash and cash equivalents at end of fiscal year		45,672,739	48,170,921	47,586,971
Parent Company
Cash flows from operating activities:
Net income		84,471	577,608	362,440
Adjustments and other		197,193	(302,109)	(40,595)
Net cash provided by (used in) operating activities		281,664	275,499	321,845
Cash flows from investing activities:
Proceeds from sales of Equity securities		139,719
Net change in loans		(1,075,059)	(1,344,323)	(2,022,860)
Purchases of premises and equipment		(11,640)	(6,649)	(40,362)
Payments for purchases of securities of subsidiaries				(65,269)
Proceeds from withdrawal of securities of subsidiaries				13,359
Net change in other investing activities		(1,310)	(4,114)	(5,336)
Net cash used in investing activities		(948,290)	(1,355,086)	(2,120,468)
Cash flows from financing activities:
Net change in short-term borrowings		(140,000)	(70,000)	(30,000)
Proceeds from issuance of long-term debt		1,075,059	1,344,323	2,022,860
Proceeds from issuance of common stock		3	3	6
Purchases of treasury stock		(2,124)	(1,611)	(1,435)
Dividends paid		(190,413)	(190,382)	(190,031)
Net change in other financing activities		437	555	971
Net cash provided by financing activities		742,962	1,082,888	1,802,371
Effect of exchange rate changes on cash and cash equivalents		540
Net increase (decrease) in cash and cash equivalents		76,876	3,301	3,748
Cash and cash equivalents at beginning of fiscal year		23,491	20,190	16,442
Cash and cash equivalents at end of fiscal year		¥ 100,367	¥ 23,491	¥ 20,190
[1]	Proceeds from sales of Equity securities as well as Purchases of Equity securities include cash activity related to Other investments for the fiscal year ended March 31 2019, the amounts of which are not significant.

Subsequent Events - (Summary of

Subsequent Events - (Summary of Redeemed Preferred Securities) (Detail) - Mizuho Capital Investment, Limited - Subsequent Event ¥ in Millions	1 Months Ended
	Jun. 30, 2019JPY (¥)
Series A
Subsequent Event [Line Items]
Aggregate redemption amount	¥ 249,500
Reason for the redemption	Arrival of optional redemption date
Series B
Subsequent Event [Line Items]
Aggregate redemption amount	¥ 53,500
Reason for the redemption	Arrival of optional redemption date