Mizuho Financial (MFG) 6-K 13 Jan 17 2016 H1 Current report (foreign) Financial data

Document and Entity Information

Document and Entity Information	6 Months Ended
	Sep. 30, 2016
Document Type	6-K
Amendment Flag	false
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	H1
Trading Symbol	MFG
Entity Registrant Name	MIZUHO FINANCIAL GROUP INC
Entity Central Index Key	1,335,730
Current Fiscal Year End Date	--03-31

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - JPY (¥) ¥ in Millions	Sep. 30, 2016	Mar. 31, 2016
Assets:
Cash and due from banks	¥ 1,408,537	¥ 1,322,597
Interest-bearing deposits in other banks	41,845,190	35,327,408
Call loans and funds sold	950,071	893,545
Receivables under resale agreements (Note 18)	9,258,713	7,805,643
Receivables under securities borrowing transactions (Note 18)	3,195,978	3,407,391
Trading account assets	30,952,945	30,020,743
Investments (Notes 3 and 17):
Available-for-sale securities (including assets pledged that secured parties are permitted to sell or repledge of ¥513,054 million at March 31, 2016 and ¥430,463 million at September 30, 2016)	20,312,495	25,452,525
Held-to-maturity securities (including assets pledged that secured parties are permitted to sell or repledge of ¥1,238,965 million at March 31, 2016 and ¥1,063,891 million at September 30, 2016)	4,260,096	4,818,961
Other investments	580,854	613,446
Loans (Notes 4, 5 and 17)	76,381,908	77,555,369
Allowance for loan losses	(437,180)	(451,247)
Loans, net of allowance	75,944,728	77,104,122
Premises and equipment-net	1,882,224	1,837,990
Due from customers on acceptances	142,654	109,567
Accrued income	247,252	274,226
Goodwill	18,822	19,097
Intangible assets	46,218	48,651
Deferred tax assets	93,186	57,349
Other	4,874,760	4,696,890
Total	196,014,723	193,810,151
Liabilities and equity:
Noninterest-bearing deposits	16,787,438	16,108,032
Interest-bearing deposits	82,101,015	79,596,483
Noninterest-bearing deposits	1,727,268	1,601,417
Interest-bearing deposits	19,691,579	20,631,790
Due to trust accounts	3,425,497	4,467,305
Call money and funds purchased	1,791,651	2,521,009
Payables under repurchase agreements (Notes 18 and 19)	17,739,124	16,833,263
Payables under securities lending transactions (Notes 18 and 19)	1,534,505	2,844,653
Other short-term borrowings	1,556,156	2,080,039
Trading account liabilities (Notes 17 and 18)	18,970,314	17,111,142
Bank acceptances outstanding	142,654	109,567
Income taxes payable	77,593	96,710
Deferred tax liabilities	151,400	201,859
Accrued expenses	171,302	181,441
Long-term debt	15,240,696	14,765,527
Other	6,641,554	6,476,723
Total	187,749,746	185,626,960
Commitments and contingencies (Note 15)
MHFG shareholders' equity:
Preferred stock (Note 7)		98,924
Common stock (Note 7)-no par value, authorized 48,000,000,000 shares at March 31, 2016 and September 30, 2016, and issued 25,030,525,657 shares at March 31, 2016, and 25,386,307,945 shares at September 30, 2016	5,802,796	5,703,144
Retained earnings	1,031,186	746,785
Accumulated other comprehensive income, net of tax (Note 9)	1,274,299	1,469,308
Less: Treasury stock, at cost-Common stock 10,929,211 shares at March 31, 2016, and 21,895,432 shares at September 30, 2016	(5,098)	(3,610)
Total MHFG shareholders' equity	8,103,183	8,014,551
Noncontrolling interests	161,794	168,640
Total equity	8,264,977	8,183,191
Total liabilities and equity	196,014,723	193,810,151
Consolidated VIEs
Assets:
Cash and due from banks	125,819	51,304
Interest-bearing deposits in other banks	96,236	85,976
Trading account assets	1,688,698	1,639,050
Investments (Notes 3 and 17):
Investments	44,967	40,732
Loans, net of allowance	2,011,933	2,255,409
Other	654,292	620,008
Total	4,621,945	4,692,479
Liabilities and equity:
Other short-term borrowings	206,341	292,614
Long-term debt	509,964	411,679
Other	1,009,861	967,141
Total	¥ 1,726,166	¥ 1,671,434

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - JPY (¥) ¥ in Millions	Sep. 30, 2016	Mar. 31, 2016
Trading account assets, assets pledged that secured parties are permitted to sell or repledge	¥ 5,563,467	¥ 7,020,645
Available-for-sale securities, assets pledged that secured parties are permitted to sell or repledge	430,463	513,054
Held-to-maturity securities, assets pledged that secured parties are permitted to sell or repledge	1,063,891	1,238,965
Long-term debt, liabilities accounted for at fair value	¥ 1,529,681	¥ 1,055,626
Common stock, par value	¥ 0	¥ 0
Common stock, authorized	48,000,000,000	48,000,000,000
Common stock, issued	25,386,307,945	25,030,525,657
Treasury stock, shares	21,895,432	10,929,211

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Interest and dividend income:
Loans, including fees	¥ 494,309	¥ 510,782
Investments:
Interest	41,303	54,785
Dividends	38,348	39,287
Trading account assets	71,746	71,701
Call loans and funds sold	2,550	3,460
Receivables under resale agreements and securities borrowing transactions	38,428	22,211
Deposits	35,383	31,382
Total interest and dividend income	722,067	733,608
Interest expense:
Deposits	116,237	96,334
Trading account liabilities	10,245	11,163
Call money and funds purchased	1,534	3,897
Payables under repurchase agreements and securities lending transactions	50,494	25,808
Other short-term borrowings	4,946	2,788
Long-term debt	85,312	87,963
Total interest expense	268,768	227,953
Net interest income	453,299	505,655
Provision (credit) for loan losses (Notes 4 and 5)	569	3,030
Net interest income after provision (credit) for loan losses	452,730	502,625
Noninterest income:
Fee and commission income	362,913	365,411
Foreign exchange gains (losses)-net	57,090	47,938
Trading account gains (losses)-net	206,061	149,142
Investment gains (losses)-net (Note 3)	128,749	149,312
Equity in earnings (losses) of equity method investees-net	16,726	20,151
Gains on disposal of premises and equipment	3,486	8,756
Other noninterest income (Note 14)	71,980	113,386
Total noninterest income	847,005	854,096
Noninterest expenses:
Salaries and employee benefits (Note 13)	326,676	315,826
General and administrative expenses	274,572	268,901
Occupancy expenses	93,958	100,777
Fee and commission expenses	76,822	77,303
Provision (credit) for losses on off-balance-sheet instruments	(7,895)	(9,324)
Other noninterest expenses (Note 14)	78,329	60,708
Total noninterest expenses	842,462	814,191
Income before income tax expense	457,273	542,530
Income tax expense (Note 12)	74,515	167,261
Net income	382,758	375,269
Less: Net income attributable to noncontrolling interests	3,200	9,396
Net income attributable to MHFG shareholders	¥ 379,558	¥ 365,873
Earnings per common share (Note 11):
Basic net income per common share	¥ 15.06	¥ 14.74
Diluted net income per common share	¥ 14.95	¥ 14.41

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Net income	¥ 382,758	¥ 375,269
Other comprehensive income (loss), net of tax	(196,229)	(297,397)
Total comprehensive income	186,529	77,872
Less: Total comprehensive income attributable to noncontrolling interests	2,310	8,069
Total comprehensive income attributable to MHFG shareholders	¥ 184,219	¥ 69,803

CONSOLIDATED STATEMENTS OF EQUI

CONSOLIDATED STATEMENTS OF EQUITY - JPY (¥) ¥ in Millions	Total	Preferred stock (Note 7):	Common stock (Note 7):	Retained earnings:	Accumulated other comprehensive income, net of tax (Note 9):	Treasury stock, at cost:	Total MHFG shareholders' equity	Noncontrolling interests:
Balance at beginning of period (Previously Reported) at Mar. 31, 2015					¥ 2,041,005
Balance at beginning of period at Mar. 31, 2015		¥ 213,121	¥ 5,590,396	¥ 89,432	2,041,005	¥ (3,616)		¥ 259,506
Issuance of new shares of common stock due to conversion of preferred stock			69,048
Effect of other increase (decrease) in consolidated subsidiaries								(25,819)
Purchases of treasury stock						(684)
Net income attributable to MHFG shareholders	¥ 365,873			365,873
Conversion to common stock		(69,048)
Change during period	(297,397)				(296,070)
Issuance of new shares of common stock due to exercise of stock acquisition rights			772
Dividends paid to noncontrolling interests								(2,246)
Disposal of treasury stock						269
Dividends declared	(100,584)			(100,584)
Gains (losses) on disposal of treasury stock			82
Net income attributable to noncontrolling interests	(9,396)							9,396
Stock-based compensation related to stock option			(1,058)
Net unrealized gains (losses) on available-for-sale securities attributable to noncontrolling interests								(1,168)
Foreign currency translation adjustments attributable to noncontrolling interests								(146)
Pension liability adjustments attributable to noncontrolling interests								(14)
Balance at end of period at Sep. 30, 2015	8,138,447	144,073	5,659,240	354,721	1,744,935	(4,031)	¥ 7,898,938	239,509
Balance at beginning of period (Previously Reported) at Mar. 31, 2016				746,785	1,469,308			168,640
Balance at beginning of period (Restatement Adjustment)				(329)	330			(10,441)
Balance at beginning of period at Mar. 31, 2016	8,183,191	98,924	5,703,144	746,456	1,469,638	(3,610)		158,199
Issuance of new shares of common stock due to conversion of preferred stock			98,924
Effect of other increase (decrease) in consolidated subsidiaries								3,256
Purchases of treasury stock						(1,869)
Net income attributable to MHFG shareholders	379,558			379,558
Conversion to common stock		¥ (98,924)
Change during period	(196,229)				(195,339)
Issuance of new shares of common stock due to exercise of stock acquisition rights			969
Dividends paid to noncontrolling interests								(1,971)
Disposal of treasury stock						380
Dividends declared	(94,828)			(94,828)
Gains (losses) on disposal of treasury stock			(55)
Net income attributable to noncontrolling interests	(3,200)							3,200
Stock-based compensation related to stock option			(1,009)
Net unrealized gains (losses) on available-for-sale securities attributable to noncontrolling interests								108
Performance-based stock compensation program			118
Foreign currency translation adjustments attributable to noncontrolling interests								(1,000)
Change in ownership interest in consolidated subsidiaries			706
Pension liability adjustments attributable to noncontrolling interests								2
Cancellation of treasury stock			(1)			1
Balance at end of period at Sep. 30, 2016	¥ 8,264,977		¥ 5,802,796	¥ 1,031,186	¥ 1,274,299	¥ (5,098)	¥ 8,103,183	¥ 161,794

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net income	¥ 382,758	¥ 375,269
Less: Net income attributable to noncontrolling interests	3,200	9,396
Net income attributable to MHFG shareholders	379,558	365,873
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	81,650	82,608
Provision (credit) for loan losses	569	3,030
Investment losses (gains)-net	(128,749)	(149,312)
Equity in losses (earnings) of equity method investees-net	(16,726)	(20,151)
Foreign exchange losses (gains)-net	(367,495)	(43,487)
Deferred income tax expense (benefit)	(27,875)	29,890
Net change in trading account assets	(575,402)	1,249,754
Net change in trading account liabilities	2,358,095	(771,660)
Net change in loans held for sale	(8,892)	(32,588)
Net change in accrued income	13,947	11,601
Net change in accrued expenses	(15,230)	(48,749)
Other-net	165,321	385,330
Net cash provided by operating activities	1,858,771	1,062,139
Cash flows from investing activities:
Proceeds from sales of investments	18,374,011	10,581,839
Proceeds from maturities of investments	3,307,892	6,161,992
Purchases of investments	(17,554,272)	(14,099,866)
Proceeds from sales of loans	126,768	62,849
Net change in loans	(1,598,393)	(1,141,961)
Net change in interest-bearing deposits in other banks	(7,061,266)	(6,148,274)
Net change in call loans and funds sold, and receivables under resale agreements and securities borrowing transactions	(2,389,471)	108,419
Proceeds from sales of premises and equipment	3,883	34,379
Purchases of premises and equipment	(214,606)	(217,527)
Net cash used in investing activities	(7,005,454)	(4,658,150)
Cash flows from financing activities:
Net change in deposits	5,292,468	2,563,948
Net change in call money and funds purchased, and payables under repurchase agreements and securities lending transactions	672,490	577,560
Net change in due to trust accounts	(1,041,808)	155,418
Net change in other short-term borrowings	(411,765)	333,078
Proceeds from issuance of long-term debt	3,567,497	1,326,988
Repayment of long-term debt	(2,688,095)	(1,271,652)
Proceeds from noncontrolling interests	361	283
Payment to noncontrolling interests		(5)
Proceeds from issuance of common stock	6	5
Proceeds from sales of treasury stock	1	2
Purchases of treasury stock	(1,430)	(8)
Dividends paid	(94,782)	(100,659)
Dividends paid to noncontrolling interests	(1,971)	(2,246)
Net cash provided by financing activities	5,292,972	3,582,712
Effect of exchange rate changes on cash and due from banks	(60,349)	(4,645)
Net increase (decrease) in cash and due from banks	85,940	(17,944)
Cash and due from banks at beginning of period	1,322,597	1,528,306
Cash and due from banks at end of period	1,408,537	1,510,362
Noncash investing activities:
Transfer of loans into other investments		63,420
Investment in capital leases	¥ 4,987	¥ 12,618

Basis of presentation

Basis of presentation	6 Months Ended
	Sep. 30, 2016
Basis of presentation	1. Basis of presentation Mizuho Financial Group, Inc. (“MHFG”) is a joint stock corporation with limited liability under the laws of Japan. MHFG, through its subsidiaries (“the MHFG Group”, or “the Group”), provides domestic and international financial services in Japan and other countries. For a discussion of the Group’s segment information, see Note 20 “Business segment information”. The accompanying consolidated financial statements have been prepared in accordance with the accounting principles generally accepted in the United States of America (“U.S. GAAP”). The consolidated financial statements are stated in Japanese yen, the currency of the country in which MHFG is incorporated and principally operates. The accompanying consolidated financial statements include the accounts of MHFG and its subsidiaries. MHFG’s interim financial reporting period ends on September 30 and certain subsidiaries’ interim financial reporting period ends on June 30. The necessary adjustments have been made to the consolidated financial statements if significant transactions took place during the three-month period. When determining whether to consolidate investee entities, the MHFG Group performed a careful 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 unaudited consolidated financial statements should be read in conjunction with the audited financial statements and related notes thereto included in the annual financial statements for the fiscal year ended March 31, 2016. Certain financial information that is normally included in annual financial statements prepared in accordance with U.S. GAAP, but is not required for interim reporting purposes, has been condensed or omitted. 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

Recently issued accounting pron

Recently issued accounting pronouncements	6 Months Ended
	Sep. 30, 2016
Recently issued accounting pronouncements	2. Recently issued accounting pronouncements Recently adopted accounting pronouncements In November 2014, the FASB issued Accounting Standards Update (“ASU”) 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 Long-term In May 2015, the FASB issued ASU No.2015-07, No.2015-07”). No.2015-07 Accounting pronouncements issued but not yet effective In May 2014, the FASB issued ASU No.2014-09, No.2014-09”). No.2015-14, No.2015-14”) No.2014-09 No.2014-09 No.2014-09 No.2014-09 No.2015-14 In January 2016, the FASB issued ASU No.2016-01, 825-10)—Recognition No.2016-01”). No.2016-01 In February 2016, the FASB issued ASU No.2016-02, No.2016-02”). right-of-use No.2016-02 In June 2016, the FASB issued ASU No.2016-13, No.2016-13”). available-for-sale No.2016-13 In October 2016, the FASB issued ASU No.2016-16, No.2016-16”). No.2016-16

Investments

Investments	6 Months Ended
	Sep. 30, 2016
Investments	3. 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) March 31, 2016 Available-for-sale Debt securities: Japanese government bonds 15,672,171 91,420 1,015 15,762,576 Japanese local government bonds 234,587 6,097 3 240,681 U.S. Treasury bonds and federal agency securities 436,792 1,720 32 438,480 Other foreign government bonds 939,808 2,740 153 942,395 Agency mortgage-backed securities (1) 920,375 29,804 1,293 948,886 Residential mortgage-backed securities 206,882 4,254 878 210,258 Commercial mortgage-backed securities 186,525 788 523 186,790 Japanese corporate bonds and other debt securities (2) 2,079,599 15,688 420 2,094,867 Foreign corporate bonds and other debt securities (3) 839,981 8,744 1,421 847,304 Equity securities (marketable) 1,663,486 2,121,379 4,577 3,780,288 Total 23,180,206 2,282,634 10,315 25,452,525 Held-to-maturity Debt securities: Japanese government bonds 3,760,032 56,620 — 3,816,652 Agency mortgage-backed securities (4) 1,058,929 3,894 6,266 1,056,557 Total 4,818,961 60,514 6,266 4,873,209 September 30, 2016 Available-for-sale Debt securities: Japanese government bonds 10,322,825 52,600 4,836 10,370,589 Japanese local government bonds 274,890 6,449 28 281,311 U.S. Treasury bonds and federal agency securities 904,552 50 767 903,835 Other foreign government bonds 926,996 1,707 110 928,593 Agency mortgage-backed securities (1) 887,307 25,285 647 911,945 Residential mortgage-backed securities 166,837 3,165 688 169,314 Commercial mortgage-backed securities 197,481 998 300 198,179 Japanese corporate bonds and other debt securities (2) 2,071,260 37,099 1,394 2,106,965 Foreign corporate bonds and other debt securities (3) 789,496 6,387 1,072 794,811 Equity securities (marketable) 1,693,665 1,956,294 3,006 3,646,953 Total 18,235,309 2,090,034 12,848 20,312,495 Held-to-maturity Debt securities: Japanese government bonds 3,459,999 54,852 — 3,514,851 Agency mortgage-backed securities (4) 800,097 4,714 1,743 803,068 Total 4,260,096 59,566 1,743 4,317,919 Notes: (1) Agency mortgage-backed securities presented in the above table consist of U.S. agency securities and Japanese agency securities, of which the fair values were ¥168,604 million and ¥780,282 million, respectively, at March 31, 2016, and ¥167,585 million and ¥744,360 million, respectively, at September 30, 2016. U.S. agency securities primarily consist of Government National Mortgage Association (“Ginnie Mae”) securities, which are guaranteed by the United States government. All Japanese agency securities are mortgage-backed securities issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise. (2) Other debt securities presented in the above table primarily consist of certificates of deposit (“CDs”) and asset-backed securities (“ABS”), of which the total fair values were ¥158,446 million at March 31, 2016, and ¥146,851 million at September 30, 2016. (3) Other debt securities presented in the above table primarily consist of CDs, ABS, and collateralized loan obligations (“CLO”), of which the total fair values were ¥201,952 million at March 31, 2016, and ¥212,641 million at September 30, 2016. (4) All Agency mortgage-backed securities presented in the above table 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 1,396,343 7,400,210 1,462,976 63,296 10,322,825 Japanese local government bonds 33,648 99,991 140,591 660 274,890 U.S. Treasury bonds and federal agency securities 823,997 — 74,569 5,986 904,552 Other foreign government bonds 720,168 201,202 5,626 — 926,996 Agency mortgage-backed securities — — — 887,307 887,307 Residential mortgage-backed securities — — — 166,837 166,837 Commercial mortgage-backed securities 1,250 128,468 67,763 — 197,481 Japanese corporate bonds and other debt securities 406,988 1,088,491 399,102 176,679 2,071,260 Foreign corporate bonds and other debt securities 204,995 428,081 68,458 87,962 789,496 Total 3,587,389 9,346,443 2,219,085 1,388,727 16,541,644 Held-to-maturity Debt securities: Japanese government bonds 999,979 1,980,160 479,860 — 3,459,999 Agency mortgage-backed securities — — — 800,097 800,097 Total 999,979 1,980,160 479,860 800,097 4,260,096 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 1,396,500 7,432,623 1,478,096 63,370 10,370,589 Japanese local government bonds 33,716 101,444 145,352 799 281,311 U.S. Treasury bonds and federal agency securities 824,007 — 74,062 5,766 903,835 Other foreign government bonds 720,490 202,207 5,896 — 928,593 Agency mortgage-backed securities — — — 911,945 911,945 Residential mortgage-backed securities — — — 169,314 169,314 Commercial mortgage-backed securities 1,250 128,443 68,486 — 198,179 Japanese corporate bonds and other debt securities 407,503 1,095,194 403,617 200,651 2,106,965 Foreign corporate bonds and other debt securities 206,085 432,423 68,370 87,933 794,811 Total 3,589,551 9,392,334 2,243,879 1,439,778 16,665,542 Held-to-maturity Debt securities: Japanese government bonds 1,003,550 2,001,089 510,212 — 3,514,851 Agency mortgage-backed securities — — — 803,068 803,068 Total 1,003,550 2,001,089 510,212 803,068 4,317,919 Other-than-temporary impairment The MHFG Group performs periodic reviews to identify impaired securities in accordance with ASC 320, “Investments—Debt and Equity 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. For equity securities, impairment is evaluated considering the length of time and extent to which the fair value has been below cost, the financial condition and near-term prospects of the issuers, as well as the MHFG Group’s ability and intent to hold these investments for a reasonable period of time sufficient for a forecasted recovery of fair value. If an equity security is deemed other-than-temporarily impaired, it shall be written down to fair value, with the full decline recognized in earnings. The following table shows the other-than-temporary impairment on available-for-sale held-to-maturity Six months ended September 30, 2015 2016 (in millions of yen) Available-for-sale Debt securities 40 56 Equity securities 6,060 10,016 Total 6,100 10,072 For the six months ended September 30, 2016, 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 320-10-35-33A ASC 320-10-35-34B, The other-than-temporary impairment losses on equity securities were mainly attributable to the decline in the fair value of certain Japanese equity securities. 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) March 31, 2016 Available-for-sale Debt securities: Japanese government bonds 1,531,400 692 74,427 323 1,605,827 1,015 Japanese local government bonds 3,434 3 — — 3,434 3 U.S. Treasury bonds and federal agency securities 315,425 32 — — 315,425 32 Other foreign government bonds 225,493 139 225 14 225,718 153 Agency mortgage-backed securities (1) 15,965 86 58,147 1,207 74,112 1,293 Residential mortgage-backed securities 2,417 3 39,984 875 42,401 878 Commercial mortgage-backed securities 40,471 300 22,465 223 62,936 523 Japanese corporate bonds and other debt securities 360,782 348 20,109 72 380,891 420 Foreign corporate bonds and other debt securities 186,478 972 22,090 449 208,568 1,421 Equity securities (marketable) 71,262 4,515 180 62 71,442 4,577 Total 2,753,127 7,090 237,627 3,225 2,990,754 10,315 Held-to-maturity Debt securities: Agency mortgage-backed securities (2) 394,673 5,384 101,892 882 496,565 6,266 Total 394,673 5,384 101,892 882 496,565 6,266 September 30, 2016 Available-for-sale Debt securities: Japanese government bonds 2,112,158 4,391 90,433 445 2,202,591 4,836 Japanese local government bonds 8,182 28 — — 8,182 28 U.S. Treasury bonds and federal agency securities 190,983 767 — — 190,983 767 Other foreign government bonds 277,723 107 3,299 3 281,022 110 Agency mortgage-backed securities (1) 41,607 232 47,609 415 89,216 647 Residential mortgage-backed securities 7,037 8 35,004 680 42,041 688 Commercial mortgage-backed securities 22,635 117 32,620 183 55,255 300 Japanese corporate bonds and other debt securities 288,591 1,177 87,971 217 376,562 1,394 Foreign corporate bonds and other debt securities 130,937 699 53,956 373 184,893 1,072 Equity securities (marketable) 159,314 1,972 4,292 1,034 163,606 3,006 Total 3,239,167 9,498 355,184 3,350 3,594,351 12,848 Held-to-maturity Debt securities: Agency mortgage-backed securities (2) — — 280,284 1,743 280,284 1,743 Total — — 280,284 1,743 280,284 1,743 Notes: (1) Agency mortgage-backed securities presented in the above table consist of U.S. agency securities and Japanese agency securities, of which the fair values were ¥69,805 million and ¥4,307 million, respectively, at March 31, 2016, and ¥54,473 million and ¥34,743 million, respectively, at September 30, 2016. U.S. agency securities primarily consist of Ginnie Mae securities, which are guaranteed by the United States government. All Japanese agency securities are mortgage-backed securities issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise. (2) All Agency mortgage-backed securities presented in the above table are Ginnie Mae securities. At September 30, 2016, 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, including Japanese corporate bonds with similar credit risks as the other-than-temporarily impaired securities, 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. The equity securities in an unrealized loss position were determined not to be other-than-temporarily impaired based on the evaluation of the following factors: (1) the severity and duration of the impairments, (2) the financial condition and near-term prospects of the issuers, and (3) the MHFG Group’s ability and intent to hold these investments for a reasonable period of time sufficient for a forecasted recovery of fair value. Realized gains and losses The following table shows the realized gains and losses on sales of available-for-sale available-for-sale Six months ended September 30, 2015 2016 (in millions of yen) Gross realized gains 128,495 144,796 Gross realized losses (14,949 ) (9,615 ) Net realized gains (losses) on sales of available-for-sale 113,546 135,181 Other investments The following table summarizes the composition of Other investments at March 31, 2016 and September 30, 2016: March 31, 2016 September 30, 2016 (in millions of yen) Equity method investments 258,180 242,744 Investments held by consolidated investment companies 42,045 37,481 Other equity interests 313,221 300,629 Total 613,446 580,854 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 ¥124,830 million and ¥120,256 million, at March 31, 2016 and September 30, 2016, respectively. The aggregate market values of these marketable equity securities were ¥277,508 million and ¥234,754 million, respectively. The MHFG Group’s proportionate share of the total outstanding common shares in Orient Corporation as of September 30, 2016 was 49.0%. 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

Loans

Loans	6 Months Ended
	Sep. 30, 2016
Loans	4. Loans The table below presents loans outstanding by domicile and industry of borrower at March 31, 2016 and September 30, 2016: March 31, 2016 September 30, 2016 (in millions of yen) Domestic: Manufacturing 8,344,808 8,086,048 Construction and real estate 7,733,513 7,666,062 Services 4,655,704 4,560,155 Wholesale and retail 5,408,850 5,100,718 Transportation and communications 3,267,902 3,528,283 Banks and other financial institutions 3,632,481 3,579,276 Government and public institutions 3,395,784 5,682,739 Other industries (Note) 4,619,336 4,244,129 Individuals: Mortgage loans 10,589,646 10,241,326 Other 924,408 912,106 Total domestic 52,572,432 53,600,842 Foreign: Commercial and industrial 17,319,284 15,784,820 Banks and other financial institutions 6,382,449 6,022,059 Government and public institutions 1,174,665 921,697 Other (Note) 273,695 202,798 Total foreign 25,150,093 22,931,374 Total 77,722,525 76,532,216 Less: Unearned income and deferred loan fees—net 167,156 150,308 Total loans before allowance for loan losses 77,555,369 76,381,908 Note: Other industries of Domestic and Other of Foreign include trade receivables and lease receivables of consolidated VIEs. 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 and pool allocations 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 groups of small balance, homogeneous loans. The Group pools loans with similar risk characteristics, and the risk is assessed 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 Mizuho Bank, Ltd. (“MHBK”) and Mizuho Trust & Banking Co., Ltd. (“MHTB”): Obligor category Obligor rating Definition Normal A Obligors whose certainty of debt fulfillment is very high, hence their level of credit risk is very low. B Obligors whose certainty of debt fulfillment poses no problems for the foreseeable future, and their level of credit risk is low. C Obligors whose certainty of debt fulfillment and their level of credit risk pose no problems for the foreseeable future. D Obligors whose current certainty of debt fulfillment poses no problems, however, their resistance to future economic environmental changes is low. Watch (Note) 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. Note: Special attention obligors are watch obligors with debt in troubled debt restructuring (“TDR”) or 90 days or more delinquent debt. Loans to such obligors are considered impaired. The table below presents credit quality information of loans based on the MHFG Group’s internal rating system at March 31, 2016 and September 30, 2016: Normal obligors Watch obligors (1) A-B C-D Retail (2) Other (3) E1-E2 Retail (2) Other (3) Impaired Total (in millions of yen) March 31, 2016 Domestic: Manufacturing 4,859,256 2,681,958 103,343 148,102 163,213 12,473 2,958 373,505 8,344,808 Construction and real estate 3,956,798 2,709,617 601,251 157,057 215,244 16,408 255 76,883 7,733,513 Services 2,611,296 1,674,328 195,140 2,380 81,704 24,846 — 66,010 4,655,704 Wholesale and retail 2,240,228 2,552,552 223,677 57,865 147,404 39,486 546 147,092 5,408,850 Transportation and communications 2,410,967 695,697 86,094 380 35,090 10,518 — 29,156 3,267,902 Banks and other financial institutions 2,719,047 881,405 2,234 3,788 22,303 264 — 3,440 3,632,481 Government and public institutions 3,181,241 4,047 — 210,496 — — — — 3,395,784 Other industries 1,954,222 685,258 3,501 1,929,712 7,053 329 35,315 3,946 4,619,336 Individuals — 259,646 10,891,538 107,131 34,744 96,729 1,659 122,607 11,514,054 Total domestic 23,933,055 12,144,508 12,106,778 2,616,911 706,755 201,053 40,733 822,639 52,572,432 Foreign: Total foreign 15,540,347 5,748,131 8,382 3,132,856 472,696 10 80,607 167,064 25,150,093 Total 39,473,402 17,892,639 12,115,160 5,749,767 1,179,451 201,063 121,340 989,703 77,722,525 September 30, 2016 Domestic: Manufacturing 4,821,589 2,511,839 94,614 114,648 152,447 12,020 3,768 375,123 8,086,048 Construction and real estate 4,038,679 2,662,926 580,874 101,261 199,136 16,775 384 66,027 7,666,062 Services 2,591,663 1,617,784 186,542 1,495 71,778 25,071 51 65,771 4,560,155 Wholesale and retail 2,158,490 2,368,145 205,881 32,117 145,727 37,476 281 152,601 5,100,718 Transportation and communications 2,682,877 688,034 84,095 205 43,046 9,691 — 20,335 3,528,283 Banks and other financial institutions 2,698,093 842,036 1,812 554 30,461 385 — 5,935 3,579,276 Government and public institutions 4,802,983 3,750 — 876,006 — — — — 5,682,739 Other industries 1,865,412 574,973 3,253 1,753,107 5,154 402 34,224 7,604 4,244,129 Individuals — 271,561 10,561,515 79,597 31,722 92,621 1,413 115,003 11,153,432 Total domestic 25,659,786 11,541,048 11,718,586 2,958,990 679,471 194,441 40,121 808,399 53,600,842 Foreign: Total foreign 14,474,511 5,101,484 9,116 2,695,051 428,832 9 72,470 149,901 22,931,374 Total 40,134,297 16,642,532 11,727,702 5,654,041 1,108,303 194,450 112,591 958,300 76,532,216 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) Amounts represent small balance, homogeneous loans which are subject to pool allocations. (3) Non-impaired Impaired loans 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 payment of the principal and interest when due. The Group classifies loans to special attention, intensive control, substantially bankrupt and bankrupt obligors as impaired loans. Impaired loans include loans past due for 90 days or more and restructured loans that meet the definition of a TDR in accordance with ASC 310, “Receivables” (“ASC 310”). 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. 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 uncertain, 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 Recorded investment (1) Requiring Not (2) Total Unpaid Related (3) Average Interest (4) (in millions of yen) March 31, 2016 Domestic: Manufacturing 365,361 8,144 373,505 379,642 138,676 410,491 7,930 Construction and real estate 59,883 17,000 76,883 87,516 10,130 89,075 1,246 Services 56,695 9,315 66,010 72,603 19,095 69,525 1,292 Wholesale and retail 134,425 12,667 147,092 157,215 46,304 149,324 2,376 Transportation and communications 25,665 3,491 29,156 30,497 5,694 33,119 630 Banks and other financial institutions 3,390 50 3,440 3,440 1,095 5,188 42 Other industries 3,591 355 3,946 4,132 799 2,665 64 Individuals 63,367 59,240 122,607 135,325 6,085 133,015 2,058 Total domestic 712,377 110,262 822,639 870,370 227,878 892,402 15,638 Foreign: Total foreign 148,471 18,593 167,064 180,870 61,308 186,440 2,629 Total 860,848 128,855 989,703 1,051,240 289,186 1,078,842 18,267 Recorded investment (1) Requiring Not (2) Total Unpaid Related (3) Average Interest (4) (in millions of yen) September 30, 2016 Domestic: Manufacturing 367,787 7,336 375,123 381,412 141,908 374,314 1,404 Construction and real estate 51,468 14,559 66,027 75,170 7,712 71,455 572 Services 58,030 7,741 65,771 72,960 19,725 65,890 604 Wholesale and retail 141,135 11,466 152,601 161,702 50,449 149,847 1,222 Transportation and communications 16,508 3,827 20,335 21,376 4,567 24,746 215 Banks and other financial institutions 3,072 2,863 5,935 5,935 1,055 4,687 30 Other industries 7,543 61 7,604 7,790 2,277 5,775 43 Individuals 57,061 57,942 115,003 126,924 5,886 118,805 967 Total domestic 702,604 105,795 808,399 853,269 233,579 815,519 5,057 Foreign: Total foreign 134,395 15,506 149,901 163,841 59,433 158,482 888 Total 836,999 121,301 958,300 1,017,110 293,012 974,001 5,945 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 small balance, homogeneous loans totaling ¥347,839 million and ¥330,764 million as of March 31, 2016 and September 30, 2016 which were collectively evaluated for impairment, in addition to the allowance for those that were individually evaluated for impairment. (4) Amounts represent gross interest income on impaired loans which were included in Interest income on loans in the consolidated statements of income. The remaining balance of impaired loans which had been partially charged off was ¥31,933 million and ¥28,803 million as of March 31, 2016 and September 30, 2016, respectively. Troubled debt restructurings The MHFG Group considers a TDR to be a restructuring in which it, for economic or legal reasons related to the obligor’s financial difficulties, grants a concession to the obligor that it would not otherwise consider. The Group considers the relevant obligor to be in financial difficulty when its obligor rating is E2 or below. The following table presents TDRs that were entered into during the six months ended September 30, 2015 and 2016: Loan forgiveness or debt to equity swaps Interest rate reduction Recorded investment (Note) Charge-offs (in millions of yen) September 30, 2015 Domestic: Manufacturing 67,058 34,081 60,865 Construction and real estate — — 15,059 Services — — 23,345 Wholesale and retail — — 77,097 Transportation and communications 49 279 12,230 Banks and other financial institutions — — 4,776 Other industries — — 2,933 Individuals — — 17,066 Total domestic 67,107 34,360 213,371 Foreign: Total foreign — — 23,971 Total 67,107 34,360 237,342 September 30, 2016 Domestic: Manufacturing — — 54,476 Construction and real estate — — 8,596 Services — — 21,951 Wholesale and retail — — 87,237 Transportation and communications — — 8,656 Banks and other financial institutions — — 3,198 Other industries — — 2,274 Individuals — — 9,205 Total domestic — — 195,593 Foreign: Total foreign — — 10,849 Total — — 206,442 Note: Amounts represent the book values of loans immediately after the restructurings. Payment default is deemed to occur when the loan becomes three months past due or the obligor is downgraded to the category of substantially bankrupt or bankrupt. The following table presents payment defaults which occurred during the six months ended September 30, 2015 and 2016 with respect to the loans modified as TDRs within the previous twelve months: Recorded investment September 30, 2015 September 30, 2016 (in millions of yen) Domestic: Manufacturing 2,890 1,801 Construction and real estate 1,731 1,621 Services 2,710 1,188 Wholesale and retail 13,097 4,614 Transportation and communications 833 771 Individuals 2,068 1,366 Total domestic 23,329 11,361 Foreign: Total foreign 6,901 30 Total 30,230 11,391 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, 2016 and September 30, 2016: 30-59 days 60-89 days 90 days or Total past Current Total (in millions of yen) March 31, 2016 Domestic: Manufacturing 1,555 163 9,454 11,172 8,333,636 8,344,808 Construction and real estate 2,713 1,024 35,691 39,428 7,694,085 7,733,513 Services 2,479 223 7,016 9,718 4,645,986 4,655,704 Wholesale and retail 3,193 886 8,861 12,940 5,395,910 5,408,850 Transportation and communications 594 81 2,033 2,708 3,265,194 3,267,902 Banks and other financial institutions — — — — 3,632,481 3,632,481 Government and public institutions — — — — 3,395,784 3,395,784 Other industries — — 29 29 4,619,307 4,619,336 Individuals 38,682 13,570 38,413 90,665 11,423,389 11,514,054 Total domestic 49,216 15,947 101,497 166,660 52,405,772 52,572,432 Foreign: Total foreign 859 2,598 30,000 33,457 25,116,636 25,150,093 Total 50,075 18,545 131,497 200,117 77,522,408 77,722,525 September 30, 2016 Domestic: Manufacturing 1,467 41 11,060 12,568 8,073,480 8,086,048 Construction and real estate 2,449 1,488 35,538 39,475 7,626,587 7,666,062 Services 1,030 572 8,046 9,648 4,550,507 4,560,155 Wholesale and retail 1,561 681 6,914 9,156 5,091,562 5,100,718 Transportation and communications 279 — 2,039 2,318 3,525,965 3,528,283 Banks and other financial institutions 16 — — 16 3,579,260 3,579,276 Government and public institutions — — — — 5,682,739 5,682,739 Other industries 41 14 28 83 4,244,046 4,244,129 Individuals 38,201 10,375 38,490 87,066 11,066,366 11,153,432 Total domestic 45,044 13,171 102,115 160,330 53,440,512 53,600,842 Foreign: Total foreign 35,917 1,251 43,508 80,676 22,850,698 22,931,374 Total 80,961 14,422 145,623 241,006 76,291,210 76,532,216 Loans held for sale 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. The outstanding balance of loans held for sale was ¥33,133 million and ¥35,024 million at March 31, 2016 and September 30, 2016, respectively.

Allowance for loan losses

Allowance for loan losses	6 Months Ended
	Sep. 30, 2016
Allowance for loan losses	5. Allowance 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 4 “Loans” for the definitions of obligor categories. Obligors in the retail portfolio segment are generally determined to be substantially bankrupt when they are past due for more than six months, and as for other obligors, the Group separately monitors the credit quality of each obligor without using time-based triggers. Subsequent recoveries of previously charged-off 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. In determining the appropriate level of the allowance, the MHFG Group evaluates the probable loss by category of loan based on its risk type and characteristics. 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 or listed securities. In obtaining the collateral, the Group evaluates the fair value of the collateral and its legal enforceability. The Group also performs subsequent re-evaluations At MHBK and MHTB, when management estimates probable credit losses to determine the allowance for loan losses, small balance, homogeneous loans are classified in the retail portfolio segment to which pool allocations apply, and loans other than these classified in the retail portfolio segment are classified in the corporate portfolio segment. The corporate portfolio segment consists of loans originated by MHBK and MHTB, and includes mainly business loans such as those used for working capital and capital expenditure, as well as loans for which the primary source of repayment of the obligation is income generated by the relevant assets such as project finance, asset finance and real estate finance. The retail portfolio segment consists mainly of residential mortgage loans, originated by MHBK. The other portfolio segment consists of loans of subsidiaries other than MHBK and MHTB, such as consolidated VIEs and overseas subsidiaries. The formula allowance is applied to groups of small balance, homogeneous loans that are collectively evaluated for impairment and to non-homogeneous 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 within 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. Changes in Allowance for loan losses by portfolio segment for the six months ended September 30, 2015 and 2016 are shown below: Corporate Retail Other Total (in millions of yen) Six months ended September 30, 2015 Balance at beginning of period 423,177 60,469 36,613 520,259 Provision (credit) for loan losses 6,878 (10,052 ) 6,204 3,030 Charge-offs (59,795 ) (1,251 ) (6,173 ) (67,219 ) Recoveries 7,733 634 1,375 9,742 Net charge-offs (52,062 ) (617 ) (4,798 ) (57,477 ) Others (Note) (971 ) — 197 (774 ) Balance at end of period 377,022 49,800 38,216 465,038 Six months ended September 30, 2016 Balance at beginning of period 367,739 44,221 39,287 451,247 Provision (credit) for loan losses 9,123 (7,983 ) (571 ) 569 Charge-offs (10,332 ) (1,016 ) (3,812 ) (15,160 ) Recoveries 8,877 4,725 2,139 15,741 Net charge-offs (1,455 ) 3,709 (1,673 ) 581 Others (Note) (10,404 ) — (4,813 ) (15,217 ) Balance at end of period 365,003 39,947 32,230 437,180 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, 2016 and September 30, 2016: Corporate Retail Other Total (in millions of yen) March 31, 2016 Allowance for loan losses 367,739 44,221 39,287 451,247 of which individually evaluated for impairment 222,591 3,829 12,521 238,941 of which collectively evaluated for impairment 145,148 40,392 26,766 212,306 Loans (Note) 59,385,962 12,414,453 5,922,110 77,722,525 of which individually evaluated for impairment 634,049 24,768 63,280 722,097 of which collectively evaluated for impairment 58,751,913 12,389,685 5,858,830 77,000,428 September 30, 2016 Allowance for loan losses 365,003 39,947 32,230 437,180 of which individually evaluated for impairment 226,809 3,441 10,803 241,053 of which collectively evaluated for impairment 138,194 36,506 21,427 196,127 Loans (Note) 58,704,366 12,017,580 5,810,270 76,532,216 of which individually evaluated for impairment 598,269 24,472 62,043 684,784 of which collectively evaluated for impairment 58,106,097 11,993,108 5,748,227 75,847,432 Note: Amounts represent loan balances before deducting unearned income and deferred loan fees.

Other assets and liabilities

Other assets and liabilities	6 Months Ended
	Sep. 30, 2016
Other assets and liabilities	6. Other assets and liabilities The following table sets forth the details of other assets and liabilities at March 31, 2016 and September 30, 2016: March 31, 2016 September 30, 2016 (in millions of yen) Other assets: Accounts receivable from brokers, dealers and customers for securities transactions 1,718,769 1,772,693 Collateral provided for derivative transactions 884,651 1,021,305 Prepaid pension cost 612,102 638,596 Miscellaneous receivables 286,896 266,944 Margins provided for futures contracts 225,240 190,893 Security deposits 113,066 112,218 Loans held for sale 33,133 35,024 Other 823,033 837,087 Total 4,696,890 4,874,760 Other liabilities: Accounts payable to brokers, dealers and customers for securities transactions 2,882,824 2,907,787 Collateral accepted for derivative transactions 715,894 979,152 Guaranteed trust principal 623,904 651,254 Miscellaneous payables 442,352 408,148 Margins accepted for futures contracts 334,925 328,362 Factoring amounts owed to customers 242,392 164,629 Unearned income 144,903 134,618 Other 1,089,529 1,067,604 Total 6,476,723 6,641,554 Guaranteed trust principal Guaranteed trust principal is the liability of certain consolidated trust arrangements, in respect of which the MHFG Group provides guarantees for the repayment of principal. See Note 16 “Variable interest entities and securitizations” for further discussion of the guaranteed principal money trusts. Unearned income Unearned income is primarily comprised of refundable fees received from consumer loan customers at the time the loan was made, which is being deferred and recognized in earnings as earned.

Preferred and common stock

Preferred and common stock	6 Months Ended
	Sep. 30, 2016
Preferred and common stock	7. Preferred and common stock The composition of preferred stock at March 31, 2016 and September 30, 2016 is as follows: March 31, 2016 Aggregate amount Number of shares Class of stock Authorized Issued In treasury (in millions of yen) Eleventh series class XI preferred stock (1) 914,752 914,752,000 914,752,000 815,828,400 First series class XIV preferred stock (2) — 900,000,000 — — Second series class XIV preferred stock (2) — 900,000,000 — — Third series class XIV preferred stock (2) — 900,000,000 — — Fourth series class XIV preferred stock (2) — 900,000,000 — — First series class XV preferred stock (3) — 900,000,000 — — Second series class XV preferred stock (3) — 900,000,000 — — Third series class XV preferred stock (3) — 900,000,000 — — Fourth series class XV preferred stock (3) — 900,000,000 — — First series class XVI preferred stock (4) — 1,500,000,000 — — Second series class XVI preferred stock (4) — 1,500,000,000 — — Third series class XVI preferred stock (4) — 1,500,000,000 — — Fourth series class XVI preferred stock (4) — 1,500,000,000 — — Total 914,752 4,214,752,000 914,752,000 815,828,400 September 30, 2016 Aggregate amount Number of shares Class of stock Authorized Issued In treasury (in millions of yen) Class XI preferred stock — 914,752,000 — — First series class XIV preferred stock (2) — 900,000,000 — — Second series class XIV preferred stock (2) — 900,000,000 — — Third series class XIV preferred stock (2) — 900,000,000 — — Fourth series class XIV preferred stock (2) — 900,000,000 — — First series class XV preferred stock (3) — 900,000,000 — — Second series class XV preferred stock (3) — 900,000,000 — — Third series class XV preferred stock (3) — 900,000,000 — — Fourth series class XV preferred stock (3) — 900,000,000 — — First series class XVI preferred stock (4) — 1,500,000,000 — — Second series class XVI preferred stock (4) — 1,500,000,000 — — Third series class XVI preferred stock (4) — 1,500,000,000 — — Fourth series class XVI preferred stock (4) — 1,500,000,000 — — Total — 4,214,752,000 — — Notes: (1) The aggregate amount and number of issued shares include the preferred stock in treasury which has been converted into common stock but not yet cancelled. (2) The total number of authorized shares from first to fourth series class XIV preferred stock shall not exceed 900,000,000. (3) The total number of authorized shares from first to fourth series class XV preferred stock shall not exceed 900,000,000. (4) The total number of authorized shares from first to fourth series class XVI preferred stock shall not exceed 1,500,000,000. The number of issued shares of common stock at March 31, 2016 and September 30, 2016 was 25,030,525,657 shares and 25,386,307,945 shares, respectively. The increase of 355,782,288 shares was due to conversion of preferred stock and exercise of stock acquisition rights.

Dividends

Dividends	6 Months Ended
	Sep. 30, 2016
Dividends	8. Dividends The following table shows dividends on preferred stock and common stock during the six months ended September 30, 2015 and 2016: September 30, 2015 Cash dividends Class of stock Per share In aggregate (in yen) (in millions of yen) Eleventh series class XI preferred stock 10 2,131 Common stock 4 98,453 Total 100,584 September 30, 2016 Cash dividends Class of stock Per share In aggregate (in yen) (in millions of yen) Eleventh series class XI preferred stock 10 989 Common stock 3.75 93,839 Total 94,828

Accumulated other comprehensive

Accumulated other comprehensive income	6 Months Ended
	Sep. 30, 2016
Accumulated other comprehensive income	9. Accumulated other comprehensive income Changes in each component of Accumulated other comprehensive income, net of tax (“AOCI”) for the six months ended September 30, 2015 and 2016 are as follows: Six months ended September 30, 2015 2016 (in millions of yen) AOCI, balance at beginning of period, previously reported 2,041,005 1,469,308 Cumulative effect of change in accounting principles (Notes 2 and 16) — 330 AOCI, balance at beginning of period, adjusted 2,041,005 1,469,638 Net unrealized gains (losses) on available-for-sale Balance at beginning of period, previously reported 1,747,607 1,409,459 Cumulative effect of change in accounting principles — (85 ) Balance at beginning of period, adjusted 1,747,607 1,409,374 Unrealized holding gains (losses) during period (179,849 ) (49,362 ) Less: reclassification adjustments for losses (gains) included in net income (72,860 ) (86,761 ) Change during period (252,709 ) (136,123 ) Balance at end of period 1,494,898 1,273,251 Foreign currency translation adjustments: Balance at beginning of period, previously reported 129,179 6,310 Cumulative effect of change in accounting principles — 415 Balance at beginning of period, adjusted 129,179 6,725 Foreign currency translation adjustments during period (43,121 ) (59,893 ) Less: reclassification adjustments for losses (gains) included in net income — — Change during period (43,121 ) (59,893 ) Balance at end of period 86,058 (53,168 ) Pension liability adjustments: Balance at beginning of period 164,219 53,539 Unrealized gains (losses) during period 1,314 533 Less: reclassification adjustments for losses (gains) included in net income (1,554 ) 144 Change during period (240 ) 677 Balance at end of period 163,979 54,216 Total other comprehensive income (loss), net of tax attributable to MHFG shareholders (296,070 ) (195,339 ) AOCI, balance at end of period 1,744,935 1,274,299 The following table shows the amounts reclassified out of AOCI into net income during the six months ended September 30, 2016: Six months ended September 30, 2016 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 125,109 (38,351 ) 86,758 3 86,761 Investment gains (losses)—net Pension liability adjustments (233 ) 87 (146 ) 2 (144 ) Salaries and employee benefits Total 124,876 (38,264 ) 86,612 5 86,617 Notes: (1) The amounts in the Before tax column are recorded in each account presented under the heading “Affected line items in the consolidated statements of income”. (2) The amounts in the Tax effect column and Net of tax attributable to noncontrolling interests column are recorded in Income tax expense and Net income attributable to noncontrolling interests in the consolidated statements of income, respectively.

Regulatory matters

Regulatory matters	6 Months Ended
	Sep. 30, 2016
Regulatory matters	10. 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. Capital adequacy ratios of MHFG, MHBK, and MHTB as of March 31, 2016 and September 30, 2016 calculated in accordance with Japanese GAAP and guidelines established by the Financial Services Agency are set forth in the following table: March 31, 2016 September 30, 2016 Amount Ratio Amount Ratio (in billions of yen, except percentages) Consolidated: MHFG: Common Equity Tier 1 capital: Required (Note) 3,361 5.375 3,314 5.375 Actual 6,566 10.50 6,769 10.98 Tier 1 capital: Required (Note) 4,299 6.875 4,238 6.875 Actual 7,905 12.64 7,983 12.94 Total risk-based capital: Required (Note) 5,550 8.875 5,471 8.875 Actual 9,639 15.41 9,768 15.84 MHBK: Common Equity Tier 1 capital: Required 2,555 4.50 2,532 4.50 Actual 6,142 10.81 6,202 11.02 Tier 1 capital: Required 3,406 6.00 3,376 6.00 Actual 7,244 12.75 7,440 13.22 Total risk-based capital: Required 4,542 8.00 4,501 8.00 Actual 8,780 15.46 9,012 16.01 MHTB: Common Equity Tier 1 capital: Required 109 4.50 108 4.50 Actual 440 18.21 452 18.80 Tier 1 capital: Required 145 6.00 144 6.00 Actual 440 18.21 452 18.80 Total risk-based capital: Required 193 8.00 192 8.00 Actual 472 19.52 479 19.95 Non-consolidated: MHBK: Common Equity Tier 1 capital: Required 2,489 4.50 2,431 4.50 Actual 5,892 10.65 5,977 11.06 Tier 1 capital: Required 3,318 6.00 3,242 6.00 Actual 7,004 12.66 7,239 13.39 Total risk-based capital: Required 4,424 8.00 4,323 8.00 Actual 8,576 15.50 8,846 16.37 MHTB: Common Equity Tier 1 capital: Required 109 4.50 109 4.50 Actual 448 18.52 462 19.05 Tier 1 capital: Required 145 6.00 145 6.00 Actual 448 18.52 462 19.05 Total risk-based capital: Required 194 8.00 194 8.00 Actual 480 19.80 489 20.16 Note: The required amounts and ratios as of March 31, 2016 and September 30, 2016 include those equivalent to a transition capital conservation buffer of 0.625% and transition additional loss absorbency requirements for a global systemically important bank (“G-SIB”) (“D-SIB”) MHFG’s securities subsidiaries in Japan are also subject to the capital adequacy requirement under the Financial Instruments and Exchange Act. Failure to maintain a minimum capital ratio will trigger mandatory regulatory actions. Management believes, as of September 30, 2016, that MHFG, MHBK, MHTB, and their securities subsidiaries in Japan were in compliance with all capital adequacy requirements to which they were subject.

Earnings per common share

Earnings per common share	6 Months Ended
	Sep. 30, 2016
Earnings per common share	11. 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 period. Diluted earnings per common share reflect the assumed conversion to common shares of all convertible securities such as convertible preferred stock. The following table sets forth the computation of basic and diluted earnings per common share for the six months ended September 30, 2015 and 2016: Six months ended 2015 2016 (in millions of yen) Net income: Net income attributable to MHFG shareholders 365,873 379,558 Less: Net income attributable to preferred shareholders 1,441 — Net income attributable to common shareholders 364,432 379,558 Effect of dilutive securities: Convertible preferred stock 1,441 — Net income attributable to common shareholders after assumed conversions 365,873 379,558 Six months ended 2015 2016 (thousands of shares) Shares: Weighted average common shares outstanding 24,718,566 25,204,801 Effect of dilutive securities: Convertible preferred stock (Note) 649,240 165,533 Stock options 18,467 11,997 Weighted average common shares after assumed conversions 25,386,273 25,382,331 Six months ended 2015 2016 (in yen) Amounts per common share: Basic net income per common share 14.74 15.06 Diluted net income per common share 14.41 14.95 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	6 Months Ended
	Sep. 30, 2016
Income taxes	12. Income taxes The following table presents the components of Income tax expense for the six months ended September 30, 2015 and 2016: Six months ended September 30, 2015 2016 (in millions of yen) Current tax expense 137,371 102,390 Deferred tax expense (benefit) 29,890 (27,875 ) Total income tax expense 167,261 74,515 The preceding table does not reflect the tax effects of items recorded directly in Equity for the six months ended September 30, 2015 and 2016. The detailed amounts recorded directly in Equity are as follows: Six months ended September 30, 2015 2016 (in millions of yen) Net unrealized gains (losses) on available-for-sale Unrealized gains (losses) (86,790 ) (21,562 ) Less: reclassification adjustments (34,567 ) (38,351 ) Total (121,357 ) (59,913 ) Foreign currency translation adjustments: Unrealized gains (losses) — (126 ) Less: reclassification adjustments — — Total — (126 ) Pension liability adjustments: Unrealized gains (losses) (118 ) 239 Less: reclassification adjustments (692 ) 87 Total (810 ) 326 Total tax effect before allocation to noncontrolling interests (122,167 ) (59,713 ) The statutory tax rates were 33.06% and 30.86% as of September 30, 2015 and 2016, respectively. The effective tax rates, 30.83% and 16.30% for the six months ended September 30, 2015 and 2016, respectively, differed from the statutory tax rates. The significant difference of the tax rates for the six months ended September 30, 2016 resulted mainly from the reversal of an outside basis difference related to foreign subsidiaries due to their organizational restructuring and was partially offset by an increase in the valuation allowance. At September 30, 2016, the MHFG Group had net operating loss carryforwards totaling ¥1,613 billion. The total amount of unrecognized tax benefits was ¥1,443 million at September 30, 2016, 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. A portion of unrecognized tax benefits at March 31, 2016 was resolved in the six months period ended September 30, 2016, of which the amount was immaterial. The amount of additional unrecognized tax benefits for the period related to the tax positions taken was also immaterial. The MHFG Group does not anticipate that increases or decreases of unrecognized tax benefits within the next twelve months would have a material effect on its consolidated results of operations or financial condition.

Pension and other employee bene

Pension and other employee benefit plans	6 Months Ended
	Sep. 30, 2016
Pension and other employee benefit plans	13. Pension and other employee benefit plans The following table summarizes the components of net periodic benefit cost of the severance indemnities and pension plans of the MHFG Group for the six months ended September 30, 2015 and 2016: Six months ended September 30, 2015 2016 (in millions of yen) Service cost-benefits earned during the period 17,803 22,219 Interest costs on projected benefit obligations 6,242 2,716 Expected return on plan assets (20,177 ) (17,860 ) Amortization of prior service benefits (97 ) (97 ) Amortization of net actuarial loss (gain) (2,049 ) 385 Special termination benefits 2,212 1,744 Net periodic benefit cost 3,934 9,107 As previously disclosed in the consolidated financial statements for the fiscal year ended March 31, 2016, the total contribution of approximately ¥50 billion is expected to be paid to the pension plans during the fiscal year ending March 31, 2017. For the six months ended September 30, 2016, the total contribution of ¥25 billion has been paid to the pension plans. The additional contribution of ¥25 billion is expected to be paid during the remainder of the fiscal year ending March 31, 2017 for a total of ¥50 billion.

Derivative financial instrument

Derivative financial instruments	6 Months Ended
	Sep. 30, 2016
Derivative financial instruments	14. 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. 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 credit risk is measured by the fair value of all derivatives in a gain position and its potential increase at the balance sheet dates. The exposure to 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, 2016 and September 30, 2016. The fair values of 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 master netting agreements in the consolidated balance sheets, or the table below. Fair value Derivative receivables (2) Derivative payables (2) March 31, 2016 Notional amount (1) Designated as Not designated Designated as Not designated (in billions of yen) Interest rate contracts 1,066,252 — 11,522 — 11,269 Foreign exchange contracts 141,517 4 3,126 1 2,979 Equity-related contracts 3,115 18 152 — 140 Credit-related contracts 4,826 — 43 — 37 Other contracts 327 — 59 — 55 Total 1,216,037 22 14,902 1 14,480 Fair value Derivative receivables (2) Derivative payables (2) September 30, 2016 Notional amount (1) Designated as Not designated Designated as Not designated (in billions of yen) Interest rate contracts 986,753 — 13,767 — 13,339 Foreign exchange contracts 134,265 6 3,127 — 2,730 Equity-related contracts 3,982 16 137 — 152 Credit-related contracts 4,164 — 31 — 32 Other contracts 317 — 45 — 41 Total 1,129,481 22 17,107 — 16,294 Notes: (1) Notional amount includes the sum of gross long and gross short third-party contracts. (2) Derivative receivables and payables are recorded in Trading account assets and Trading account liabilities, respectively. The MHFG Group provided and/or accepted cash collateral for derivative transactions under master netting agreements. The cash collateral, not offset against derivative positions, was included in Other assets and Other liabilities, respectively, of which the amounts were ¥885 billion and ¥716 billion at March 31, 2016, and ¥1,021 billion and ¥979 billion at September 30, 2016, 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 available-for-sale The following table summarizes gains and losses information related to fair value hedges for the six months ended September 30, 2015 and 2016: Gains (losses) recorded in income Six months ended September 30, 2015 Derivatives Hedged Hedge Net gain (loss) excluded (in millions of yen) Equity-related contracts 13,450 (14,798 ) — (1,348 ) Total 13,450 (14,798 ) — (1,348 ) Gains (losses) recorded in income Six months ended September 30, 2016 Derivatives Hedged Hedge Net gain (loss) excluded (in millions of yen) Equity-related contracts 6,002 (7,807 ) — (1,805 ) Total 6,002 (7,807 ) — (1,805 ) 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 six months ended September 30, 2015 and 2016: Gains (losses) recorded in income and other comprehensive income (“OCI”) 2015 2016 Effective portion Ineffective portion Effective portion Ineffective portion (in millions of yen) Financial instruments hedging foreign exchange risk 723 200 107,528 890 Total 723 200 107,528 890 Note: No amount related to the effective portion of net investment hedges was reclassified from Accumulated other comprehensive income to earnings for the six months ended September 30, 2015 and 2016, respectively. 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 hedging strategies: (1) interest-rate swap transactions for the purpose of hedging the interest-rate risks in deposits, loans etc., (2) currency swap transactions for the purpose of hedging the foreign exchange risk of these assets, and (3) credit derivatives for the purpose of hedging the credit risk in loans, residential mortgage-backed securities (“RMBS”), commercial mortgage-backed securities (“CMBS”), 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 six months ended September 30, 2015 and 2016: Gains (losses) recorded in income 2015 2016 (in millions of yen) Interest rate contracts 150,748 80,040 Foreign exchange contracts (4,453 ) 11,173 Equity-related contracts (1) 10,268 11,049 Credit-related contracts (2) (8,419 ) (4,827 ) Other contracts 451 564 Total 148,595 97,999 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 gain (loss) of ¥3,531 million and ¥(5,698) million on the credit derivatives hedging the credit risk of loans during the six months ended September 30, 2015 and 2016, 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 any 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, 2016 and September 30, 2016: March 31, 2016 September 30, 2016 Notional amount Fair value Notional amount Fair value (in billions of yen) Credit protection written: Investment grade 1,603 14 1,678 23 Non-investment 763 1 414 3 Total 2,366 15 2,092 26 Credit protection purchased 2,592 (9 ) 2,225 (27 ) 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, 2016 and September 30, 2016: Maximum payout/Notional amount March 31, 2016 September 30, 2016 (in billions of yen) One year or less 538 492 After one year through five years 1,729 1,336 After five years 99 264 Total 2,366 2,092 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, 2016 and September 30, 2016: March 31, 2016 September 30, 2016 (in billions of yen) Aggregate fair value of derivative instruments with credit-risk-related contingent features in net liability positions 790 815 Collateral provided to counterparties in normal course of business 746 775 Amount required to be posted as collateral or settled immediately if credit-risk-related contingent features were triggered 44 40

Commitments and contingencies

Commitments and contingencies	6 Months Ended
	Sep. 30, 2016
Commitments and contingencies	15. Commitments and contingencies Obligations under guarantees The MHFG Group provides guarantees or indemnifications to counterparties to enhance their credit standing and enable them to complete a variety of business transactions. A guarantee represents an obligation to make payments to third parties if the counterparty fails to fulfill its obligation under a borrowing arrangement or other contractual obligation. The Group records all guarantees and similar obligations subject to ASC 460, “Guarantees” (“ASC 460”) at fair value in the consolidated balance sheets at the inception of the guarantee. The table below summarizes the maximum potential amount of future payments by type of guarantee at March 31, 2016 and September 30, 2016. The maximum potential amount of future payments disclosed below represents the contractual amounts that could be required to be repaid in the event of the guarantees being executed, without consideration of possible recoveries under recourse provisions or from collateral held. With respect to written options included in derivative financial instruments in the table below, in theory, the MHFG Group is exposed to unlimited losses; therefore, the table shows the notional amounts of the contracts as a substitute for the maximum exposure. March 31, September 30, (in billions of yen) Performance guarantees 2,110 2,065 Guarantees on loans 297 252 Guarantees on securities 203 176 Other guarantees 1,571 1,559 Guarantees for the repayment of trust principal 1,141 433 Liabilities of trust accounts 12,747 13,828 Derivative financial instruments 15,792 15,264 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, 2016 and September 30, 2016: March 31, September 30, (in billions of yen) Investment grade 3,160 3,075 Non-investment 1,022 977 Total 4,182 4,052 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 The table below summarizes the contractual amounts with regard to these undrawn commitments at March 31, 2016 and September 30, 2016: March 31, September 30, (in billions of yen) Commitments to extend credit (Note) 75,742 72,946 Commercial letters of credit 448 428 Total 76,190 73,374 Note: Commitments to extend credit include commitments to invest in securities. 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 and 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 because 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	6 Months Ended
	Sep. 30, 2016
Variable interest entities and securitizations	16. 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, and structured finance. 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 comprehensively 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, 2016 and September 30, 2016: Consolidated VIEs Significant March 31, 2016 Consolidated assets Total assets Maximum (in billions of yen) Asset-backed commercial paper/loan programs 2,092 — — Asset-backed securitizations 579 205 13 Investments in securitization products 337 445 154 Investment funds 1,660 2,422 367 Trust arrangements and other 24 — — Total 4,692 3,072 534 Consolidated VIEs Significant September 30, 2016 Consolidated assets Total assets Maximum (in billions of yen) Asset-backed commercial paper/loan programs 1,860 — — Asset-backed securitizations 677 199 7 Investments in securitization products 336 445 154 Investment funds 1,726 3,589 523 Trust arrangements and other 23 — — Total 4,622 4,233 684 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, 2016 and September 30, 2016: Assets on balance sheets related to unconsolidated VIEs: March 31, September 30, (in billions of yen) Trading account assets 55 70 Investments 254 348 Loans 205 210 Total 514 628 Liabilities on balance sheets and maximum exposure to loss related to unconsolidated VIEs: March 31, September 30, (in billions of yen) Payables under securities lending transactions 27 27 Trading account liabilities 1 1 Total 28 28 Maximum exposure to loss (Note) 534 684 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’ off-balance-sheet Asset-backed securitizations The MHFG Group acts as an arranger of various types of structured finance to meet clients’ 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 in 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 in the VIEs or to manage these assets. In addition, through the principal guarantee agreement, 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 15 “Commitments and contingencies” for the balances of guaranteed trust principal that are not consolidated at March 31, 2016 and September 30, 2016. 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. Securitization The MHFG Group engages in securitization activities and securitizes mortgage loans, other loans, government and corporate securities and other types of financial assets in the normal course of business. In these securitization transactions, the Group records the transfer of a financial asset as a sale when all the accounting criteria for a sale under ASC 860, “Transfers and Servicing” (“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 six months ended September 30, 2015 and 2016, 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, 2016 and September 30, 2016. 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 ¥243 billion and ¥64 billion as of March 31, 2016, and ¥224 billion and ¥48 billion as of September 30, 2016, 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.

Fair value

Fair value	6 Months Ended
	Sep. 30, 2016
Fair value	17. Fair value Fair value measurements ASC 820, “Fair Value Measurements” (“ASC 820”), defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. ASC 820 also establishes a fair value hierarchy which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. In addition, ASC 820 precludes (1) the deferral of gains and losses at inception of certain derivative contracts whose fair value was not evidenced by market-observable data, and (2) the use of block discounts when measuring the fair value of instruments traded in an active market, which were previously applied to large holdings of publicly traded financial instruments. Fair value hierarchy ASC 820 specifies a hierarchy of valuation techniques based on whether the inputs to those valuation techniques are observable or unobservable. The standard describes three levels of inputs that may be used to measure fair value: Level 1 Quoted prices in active markets for identical assets or liabilities. Level 1 assets and liabilities include debt and equity securities and derivative contracts that are traded in an active exchange market. Level 2 Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 2 assets and liabilities include debt securities with quoted prices that are traded less frequently than exchange-traded instruments. If no quoted market prices are available, the fair values of debt securities and over-the-counter Level 3 Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities include financial instruments whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. Valuation process The MHFG Group has established clear valuation policies which govern the principles of fair value measurements and the authority and duty of each department. The Group has also established well-documented 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 “ Investments” The following is a description of valuation methodologies and inputs used for assets and liabilities measured at fair value on a recurring basis, including the general classification of such instruments pursuant to the fair value hierarchy and the MHFG Group’s valuation techniques used to measure fair values. During the six months ended September 30, 2016, 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 Ginnie Mae 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 a pricing model 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 foreign currency denominated securitization products such as RMBS, CMBS, and ABS 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. Among investment funds, exchange-traded funds (“ETF”) are generally classified in Level 1. Investment trusts and hedge funds are measured at the net asset value (“NAV”) per share and the Group has the ability to redeem its investment with the investees at the NAV per share at the measurement date or within the near term. Private equity funds and real estate funds are measured at the NAV per share and the Group does not have the ability to redeem its investment with the investees at the NAV per share at the measurement date or within the near term. It is estimated that the underlying assets of the funds would be liquidated within a 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 Investments The fair values of available-for-sale non-binding Other investments, except for investments held by consolidated investment companies, have not been measured at fair value on a recurring basis. Investments held by consolidated investment companies mainly consist of marketable and non-marketable non-marketable Non-marketable Long-term debt Where fair value accounting has been elected for structured notes, the fair values are determined by incorporating the fair values of embedded derivatives that are primarily derived by using the same procedures described for derivative financial instruments above. Such instruments are classified in Level 2 or Level 3 depending on the observability of significant inputs to the model used in determining the fair value of the embedded derivatives. Items measured at fair value on a recurring basis Assets and liabilities measured at fair value on a recurring basis at March 31, 2016 and September 30, 2016, including those for which the MHFG Group has elected the fair value option, are summarized below: March 31, 2016 Level 1 Level 2 Level 3 Assets/ (in billions of yen) Assets: Trading securities (1) Japanese government bonds 2,272 31 — 2,303 Japanese local government bonds — 79 — 79 U.S. Treasury bonds and federal agency securities 3,729 77 — 3,806 Other foreign government bonds 2,192 373 — 2,565 Agency mortgage-backed securities 995 563 — 1,558 Residential mortgage-backed securities — — 21 21 Commercial mortgage-backed securities — 2 2 4 Certificates of deposit and commercial paper — 881 — 881 Corporate bonds and other 9 1,693 720 2,422 Equity securities 758 62 21 841 Trading securities measured at net asset value (2) 617 Derivatives: Interest rate contracts 97 11,396 29 11,522 Foreign exchange contracts 23 3,099 8 3,130 Equity-related contracts 46 95 29 170 Credit-related contracts — 40 3 43 Other contracts — 21 38 59 Available-for-sale Japanese government bonds 15,037 726 — 15,763 Japanese local government bonds — 241 — 241 U.S. Treasury bonds and federal agency securities 438 — — 438 Other foreign government bonds 352 590 — 942 Agency mortgage-backed securities 169 780 — 949 Residential mortgage-backed securities — 87 123 210 Commercial mortgage-backed securities — — 187 187 Japanese corporate bonds and other debt securities — 1,921 174 2,095 Foreign corporate bonds and other debt securities — 739 108 847 Equity securities (marketable) 3,716 — — 3,716 Available-for-sale (2) 65 Other investments — — 42 42 Total assets measured at fair value on a recurring basis 29,833 23,496 1,505 55,516 Liabilities: Trading securities sold, not yet purchased 2,482 148 — 2,630 Derivatives: Interest rate contracts 98 11,168 3 11,269 Foreign exchange contracts 26 2,953 1 2,980 Equity-related contracts 60 56 24 140 Credit-related contracts — 33 4 37 Other contracts — 18 37 55 Long-term debt (3) — 433 623 1,056 Total liabilities measured at fair value on a recurring basis 2,666 14,809 692 18,167 September 30, 2016 Level 1 Level 2 Level 3 Assets/ (in billions of yen) Assets: Trading securities (1) Japanese government bonds 2,404 17 — 2,421 Japanese local government bonds — 51 — 51 U.S. Treasury bonds and federal agency securities 2,930 96 — 3,026 Other foreign government bonds 1,697 335 — 2,032 Agency mortgage-backed securities 1,381 572 — 1,953 Residential mortgage-backed securities — — 17 17 Commercial mortgage-backed securities — 2 — 2 Certificates of deposit and commercial paper — 617 — 617 Corporate bonds and other 5 1,303 976 2,284 Equity securities 767 60 18 845 Trading securities measured at net asset value (2) 576 Derivatives: Interest rate contracts 70 13,672 25 13,767 Foreign exchange contracts 24 3,102 7 3,133 Equity-related contracts 42 90 21 153 Credit-related contracts — 28 3 31 Other contracts 1 8 36 45 Available-for-sale Japanese government bonds 9,624 747 — 10,371 Japanese local government bonds — 281 — 281 U.S. Treasury bonds and federal agency securities 904 — — 904 Other foreign government bonds 374 555 — 929 Agency mortgage-backed securities 168 744 — 912 Residential mortgage-backed securities — 69 100 169 Commercial mortgage-backed securities — — 198 198 Japanese corporate bonds and other debt securities — 1,931 176 2,107 Foreign corporate bonds and other debt securities — 688 107 795 Equity securities (marketable) 3,552 — — 3,552 Available-for-sale (2) 95 Other investments — — 37 37 Total assets measured at fair value on a recurring basis 23,943 24,968 1,721 51,303 Liabilities: Trading securities sold, not yet purchased 2,422 253 1 2,676 Derivatives: Interest rate contracts 73 13,263 3 13,339 Foreign exchange contracts 19 2,710 1 2,730 Equity-related contracts 62 59 31 152 Credit-related contracts — 29 3 32 Other contracts — 6 35 41 Long-term debt (3) — 939 591 1,530 Total liabilities measured at fair value on a recurring basis 2,576 17,259 665 20,500 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 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, 2016 and September 30, 2016 were ¥30 billion and ¥28 billion, respectively. (3) Amounts represent items for which the Group elected the fair value option. 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 six months ended September 30, 2015 and 2016: Six months ended September 30, 2015 April 1, Gains Gains Transfers Transfers Purchases Sales Issuances Settle- September 30, Change in (losses) (6) (in billions of yen) Assets: Trading securities: Other foreign government bonds — — (2) — — — 1 (1 ) — — — — Residential mortgage-backed securities 29 — (2) — — — — — — (5 ) 24 — Commercial mortgage-backed securities 4 — (2) — — — — — — (1 ) 3 — Corporate bonds and other 639 (4 ) (2) — 8 (20 ) 233 (88 ) — (40 ) 728 (5 ) Equity securities 23 (2 ) (2) — — — — (1 ) — — 20 (2 ) Derivatives, net (1) Interest rate contracts 18 (6 ) (2) — — — — — — 6 18 (5 ) Foreign exchange contracts 8 4 (2) — — — — — — (4 ) 8 (1 ) Equity-related contracts (14 ) 15 (2) — — — — — — — 1 12 Credit-related contracts (1 ) — (2) — — — — — — 1 — — Available-for-sale Residential mortgage-backed securities 166 — (3) — (4) — — — (4 ) — (22 ) 140 — Commercial mortgage-backed securities 169 — (3) — (4) — — 56 (37 ) — (5 ) 183 — Japanese corporate bonds and other debt securities 155 1 (3) 7 (4) — — 55 (3 ) — (23 ) 192 — Foreign corporate bonds and other debt securities 85 1 (3) (6 ) (4) 23 — 37 — — (23 ) 117 — Other investments 53 8 (3) — — — 1 (19 ) — (2 ) 41 (7 ) Liabilities: Trading securities sold, not yet purchased — — (2) — — — (1 ) 1 — — — — Long-term debt 587 27 (5) — 1 (1 ) — — 160 (139 ) 581 27 Six months ended September 30, 2016 April 1, Gains Gains Transfers Transfers Purchases Sales Issuances Settle- September 30, Change in (losses) (6) (in billions of yen) Assets: Trading securities: Residential mortgage-backed securities 21 — (2) — — — — — — (4 ) 17 — Commercial mortgage-backed securities 2 — (2) — — — — — — (2 ) — — Corporate bonds and 720 (53 ) (2) — 280 (2 ) 343 (241 ) — (71 ) 976 (39 ) Equity securities 21 4 (2) — — — — (7 ) — — 18 4 Derivatives, net (1) Interest rate contracts 26 (4 ) (2) — — — — — — — 22 (3 ) Foreign exchange contracts 7 6 (2) — — — — — — (7 ) 6 — Equity-related contracts 5 (13 ) (2) — — — — — — (2 ) (10 ) (19 ) Credit-related contracts (1 ) 1 (2) — — — — — — — — — Other contracts 1 — (2) — — — — — — — 1 — Available-for-sale Residential mortgage-backed securities 123 — (3) — (4) — — — (1 ) — (22 ) 100 — Commercial mortgage-backed securities 187 — (3) — (4) — — 20 — — (9 ) 198 — Japanese corporate bonds and other debt securities 174 — (3) 22 (4) — — 1 (4 ) — (17 ) 176 — Foreign corporate bonds and other debt securities 108 1 (3) (7 ) (4) — — 10 — — (5 ) 107 — Other investments 42 (3 ) (3) — — — 11 — — (13 ) 37 (1 ) Liabilities: Trading securities sold, not yet purchased — — (2) — 1 — (32 ) 32 — — 1 — Long-term debt 623 9 (5) — — (12 ) — — 147 (158 ) 591 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 September 30, 2015 and 2016. 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 six months ended September 30, 2015, the transfers into Level 3 included ¥8 billion of Trading securities, ¥23 billion of Available-for-sale Available-for-sale During the six months ended September 30, 2016, the transfers into Level 3 included ¥280 billion of Trading securities and ¥1 billion of Trading securities sold, not yet purchased. Transfers into Level 3 for Trading securities and Trading securities sold, not yet purchased were primarily due to decreased liquidity for certain Japanese and foreign corporate bonds. During the six months ended September 30, 2016, the transfers out of Level 3 included ¥2 billion of Trading securities and ¥12 billion of Long-term debt. Transfers out of Level 3 for Trading securities were primarily due to increased price transparency for certain Japanese and foreign corporate bonds. Transfers out of Level 3 for Long-term debt were primarily due to changes in the impact of unobservable inputs on the value of certain structured notes. 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, 2016 and September 30, 2016: March 31, 2016 Products/Instruments Fair value Principal valuation technique Unobservable inputs Range of input values Weighted average (5) (in billions of yen, except for ratios and basis points) Trading securities and Available-for-sale Residential mortgage-backed securities 144 Discounted cash flow Price-based Prepayment rate Default rate Recovery rate Discount margin 3% - 19% 0% - 2% 100% - 100% 13bps - 180bps 7% 0% 100% 60bps Commercial mortgage-backed securities 189 Discounted cash flow Price-based Discount margin 6bps - 580bps 37bps Corporate bonds and other debt securities 1,002 Discounted cash flow Price-based Prepayment rate (1) Default rate (1) Recovery rate (1) Discount margin (1) Discount margin (2) 0% - 21% 0% - 2% 60% - 69% 11bps - 1,115bps 10bps - 3,850bps 19% 2% 68% 151bps 454bps Derivatives, net: Interest rate contracts 26 Internal valuation model (3) IR – IR correlation Default rate (4) 32% - 100% 0% - 63% Foreign exchange contracts 7 Internal valuation model (3) FX – IR correlation FX – FX correlation Default rate (4) 5% - 50% 54% - 54% 0% - 63% Equity-related contracts 5 Internal valuation model (3) Equity – IR correlation Equity – FX correlation Equity volatility 30% - 30% 55% - 55% 10% - 40% Credit-related contracts (1 ) Internal valuation model (3) Default rate Credit correlation 0% - 42% 29% - 100% Long-term debt 623 Internal valuation model (3) IR – IR correlation FX – IR correlation FX – FX correlation Equity – IR correlation Equity – FX correlation Equity correlation Equity volatility Default rate Credit correlation 32% - 100% 5% - 50% 54% - 54% 30% - 30% 55% - 55% 18% - 100% 14% - 39% 0% - 5% 28% - 100% September 30, 2016 Products/Instruments Fair value Principal valuation technique Unobservable inputs Range of input values Weighted average (5) (in billions of yen, except for ratios and basis points) Trading securities and Available-for-sale Residential mortgage-backed securities 117 Discounted cash flow Price-based Prepayment rate Default rate Recovery rate Discount margin 3% - 19% 0% - 2% 100% - 100% 15bps - 170bps 7% 0% 100% 59bps Commercial mortgage-backed securities 198 Discounted cash flow Price-based Discount margin 4bps - 184bps 30bps Corporate bonds and other debt securities 1,259 Discounted cash flow Price-based Prepayment rate (1) (1) Recovery rate (1) Discount margin (1) 14% - 23% 1% - 2% 60% - 69% 13bps - 1,109bps 22% 2% 68% 133bps Discount margin (2) -32bps - 2,987bps 422bps Derivatives, net: Interest rate contracts 22 Internal valuation model (3) IR – IR correlation Default rate (4) 23% - 100% 0% - 63% Foreign exchange contracts 6 Internal valuation model (3) FX – IR correlation FX – FX correlation Default rate (4) 1% - 50% 55% - 55% 0% - 63% Equity-related contracts (10 ) Internal valuation model (3) Equity – IR correlation Equity – FX correlation Equity volatility 25% - 25% 55% - 55% 6% - 48% Credit-related contracts — Internal valuation model (3) Default rate Credit correlation 0% - 59% 28% - 100% Long-term debt 591 Internal valuation model (3) IR – IR correlation FX – IR correlation FX – FX correlation Equity – IR correlation Equity – FX correlation Equity correlation Equity volatility Default rate Credit correlation 23% - 100% 1% - 50% 55% - 55% 25% - 25% 55% - 55% 18% - 100% 7% - 42% 0% - 3% 34% - 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 Sensitivity to unobservable inputs and interrelationship 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, 2016 and September 30, 2016: March 31, 2016 Total Level 1 Level 2 Level 3 Aggregate cost (in billions of yen) Assets: Loans 124 — — 124 197 Loans held-for-sale 13 — 7 6 14 Other investments 1 — — 1 2 Premises and equipment—net — — — — 1 Goodwill — — — — 6 Total assets measured at fair value on a nonrecurring basis 138 — 7 131 220 September 30, 2016 Total Level 1 Level 2 Level 3 Aggregate cost (in billions of yen) Assets: Loans 118 — — 118 185 Loans held-for-sale 4 — 4 — 4 Other investments 5 4 — 1 9 Total assets measured at fair value on a nonrecurring basis 127 4 4 119 198 Loans in the table above have been impaired and measured based upon the fair value of the underlying collateral. Loans held-for-sale Other investments in the table above, which consist of certain equity method investments and non-marketable non-marketable non-marketable non-marketable Premises and equipment—net in the table above have been impaired and written down to fair value. Goodwill in the table above is entirely related to Banco Mizuho do Brasil S.A. reporting unit. Due to the decline in the fair value of the reporting unit, the carrying amount of the goodwill was reduced to its fair value which is based on market approach and an impairment loss was recognized. As the determination of the fair value of the goodwill required significant management judgment and estimation, it is classified as Level 3. Fair value option The MHFG Group elected the fair value option for certain eligible financial instruments described below. Foreign currency denominated available-for-sale Prior to the adoption of the fair value option in accordance with ASC 825, “Financial Instruments” (“ASC 825”), the changes in fair value of foreign currency denominated available-for-sale available-for-sale 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 ¥20 billion and ¥22 billion at March 31, 2016 and September 30, 2016, respectively. The net unrealized gains (losses) resulting from changes in fair values of these notes of ¥28 billion and ¥2 billion, which included the fair value changes attributable to changes in the Group’s own credit risk, were recorded in Other noninterest income (expenses) for the six months ended September 30, 2015 and 2016, respectively. 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. ASC 825 does not require the disclosure of the fair value of nonfinancial instruments. 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, 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 Performing loans have been fair valued as groups of similar loans based on the type of loan, credit quality, prepayment assumptions and remaining maturity. The fair value of performing 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 impaired loans is determined based on either discounted cash flows incorporating the Group’s best estimate of the expected future cash flows or the fair value of the underlying collateral, if impaired loans are collateral dependent. 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 6 “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

Offsetting of financial assets

Offsetting of financial assets and financial liabilities	6 Months Ended
	Sep. 30, 2016
Offsetting of financial assets and financial liabilities	18. Offsetting of financial assets and financial liabilities Derivatives The MHFG Group enters into master netting arrangements such as International Swaps and Derivatives Association, Inc. (“ISDA”) or similar agreements with counterparties to manage mainly credit risks associated with counterparty default. If the predetermined events including counterparty default occur, these enforceable master netting arrangements or similar agreements give the Group the right to offset derivative receivables and derivative payables and related financial collateral such as cash and securities with the same counterparty. Repurchase and resale agreements and securities lending and borrowing transactions Repurchase and resale agreements and securities lending and borrowing transactions are generally covered by industry standard master repurchase agreements and industry standard master securities lending agreements with netting terms to manage mainly credit risks associated with counterparty default. In the event of default by the counterparty, these agreements with netting terms provide the Group with the right to offset receivables and payables related to such transactions with the same counterparty, and to liquidate the collateral held. The following table provides information about the offsetting of financial assets and financial liabilities at March 31, 2016 and September 30, 2016. 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 (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) March 31, 2016 Assets (1) Derivatives 14,130 — 14,130 (12,167 ) (599 ) 1,364 Receivables under resale agreements 7,490 — 7,490 (7,461 ) — 29 Receivables under securities borrowing transactions 3,327 — 3,327 (3,318 ) — 9 Total 24,947 — 24,947 (22,946 ) (599 ) 1,402 Liabilities (1) Derivatives 13,652 — 13,652 (12,043 ) (748 ) 861 Payables under repurchase agreements 16,507 — 16,507 (16,464 ) — 43 Payables under securities lending transactions 2,538 — 2,538 (2,531 ) — 7 Total 32,697 — 32,697 (31,038 ) (748 ) 911 September 30, 2016 Assets (1) Derivatives 15,916 — 15,916 (13,562 ) (709 ) 1,645 Receivables under resale agreements 9,068 — 9,068 (9,028 ) — 40 Receivables under securities borrowing transactions 3,060 — 3,060 (3,046 ) — 14 Total 28,044 — 28,044 (25,636 ) (709 ) 1,699 Liabilities (1) Derivatives 15,152 — 15,152 (13,471 ) (910 ) 771 Payables under repurchase agreements 17,250 — 17,250 (17,142 ) — 108 Payables under securities lending transactions 1,188 — 1,188 (1,180 ) — 8 Total 33,590 — 33,590 (31,793 ) (910 ) 887 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	6 Months Ended
	Sep. 30, 2016
Repurchase agreements and securities lending transactions accounted for as secured borrowings	19. Repurchase agreements and securities lending transactions accounted for as secured borrowings The following table shows the gross amounts of liabilities associated with repurchase agreements and securities lending transactions, by remaining contractual maturity at March 31, 2016 and September 30, 2016: Overnight and Up to 30 days 31-90 days Greater than 90 Total (in billions of yen) March 31, 2016 Repurchase agreements 6,289 6,125 3,582 837 16,833 Securities lending transactions 1,909 700 — 236 2,845 Total 8,198 6,825 3,582 1,073 19,678 September 30, 2016 Repurchase agreements 327 12,847 3,362 1,203 17,739 Securities lending transactions 182 1,133 — 220 1,535 Total 509 13,980 3,362 1,423 19,274 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, 2016 and September 30, 2016: Repurchase Securities lending (in billions of yen) March 31, 2016 Japanese government bonds and Japanese local government bonds 532 1,891 Foreign government bonds and foreign agency mortgage-backed securities 15,781 700 Commercial paper and corporate bonds 221 27 Equity securities 141 185 Other 158 42 Total (Note) 16,833 2,845 September 30, 2016 Japanese government bonds and Japanese local government bonds 634 717 Foreign government bonds and foreign agency mortgage-backed securities 16,087 579 Commercial paper and corporate bonds 486 29 Equity securities 380 182 Other 152 28 Total (Note) 17,739 1,535 Note: Amounts exceeded the gross amounts recognized in Note 18 “Offsetting of financial assets and financial liabilities” by ¥633 billion and ¥836 billion, at March 31, 2016 and September 30, 2016, 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 daily basis, diversifying the maturities and counterparties, and using mainly highly liquid securities.

Business segment information

Business segment information	6 Months Ended
	Sep. 30, 2016
Business segment information	20. Business segment information The MHFG Group has introduced an in-house Specifically, the company system is classified into the following five in-house In line with the aforementioned system, the reportable segments have been changed from those based on the relevant principal consolidated subsidiaries to the five in-house 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 each business segment’s net business profits with income before income tax expense under U.S. GAAP. Management does not use information on business segment’s assets to allocate resources and assess performance and has not prepared information on the segment’s assets. Accordingly, information on the segment’s assets is not available. MHFG (Consolidated) Six months ended September 30, 2015 (1) Retail & Corporate & Global Global Asset Others (3) Total (in billions of yen) Gross profits 332.1 209.5 204.8 332.3 26.6 26.5 1,131.8 General and administrative expenses 331.1 91.3 111.6 88.5 15.0 34.8 672.3 Others — — — — — (12.8 ) (12.8 ) Net business profits (losses) (2) 1.0 118.2 93.2 243.8 11.6 (21.1 ) 446.7 MHFG (Consolidated) Six months ended September 30, 2016 Retail & Corporate & Global Global Asset Others (3) Total (in billions of yen) Gross profits 310.8 223.2 192.7 334.3 24.5 4.2 1,089.7 General and administrative expenses 338.8 92.9 115.5 94.6 15.0 23.7 680.5 Others — — — — — (6.0 ) (6.0 ) Net business profits (losses) (2) (28.0 ) 130.3 77.2 239.7 9.5 (25.5 ) 403.2 Notes: (1) Following the introduction of an in-house (2) Net business profits is used in Japan as a measure of the profitability of core banking operations, and is defined as gross profits (or the sum of net interest income, fiduciary income, net fee and commission income, net trading income and net other operating income) less general and administrative expenses. 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. 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 total net business profits under the internal management reporting systems for the six months ended September 30, 2015 and 2016 presented above to income before income tax expense shown on the consolidated statements of income is as follows: Six months ended September 30, 2015 2016 (in billions of yen) Net business profits 446.7 403.2 U.S. GAAP adjustments (67.6 ) 14.8 (Provision) credit for loan losses (3.0 ) (0.6 ) Net gains (losses) related to equity investments 122.6 64.5 Non-recurring (0.8 ) (4.7 ) Gains on disposal of premises and equipment 8.8 3.5 (Provision) credit for losses on off-balance-sheet 9.3 7.9 Others—net 26.5 (31.3 ) Income before income tax expense 542.5 457.3

Subsequent events

Subsequent events	6 Months Ended
	Sep. 30, 2016
Subsequent events	21. Subsequent events 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 Co., Ltd. (“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. On October 1, 2016, MHFG exchanged 30.0% of the voting equity interests in MHAM (after the split in (ii) above) for voting equity interests and non-voting Based on the strong commitment of MHFG and Dai-ichi (“Dai-ichi Dai-ichi The following table summarizes the consideration paid for DIAM. Since the MHFG Group is currently calculating the amounts recognized at the acquisition date for each major class of acquired assets and assumed liabilities as well as the fair value at the acquisition date of the noncontrolling interest in DIAM, such information could not be included in the consolidated financial statements. There were no material acquisition-related costs that were recognized separately from the acquisitions of the assets and the assumptions of the liabilities. At October 1, (in billions of yen) Consideration Equity instruments (1,038,408 common shares of MHAM) 29 Fair value of total consideration transferred 29 Fair value of equity interests in DIAM held by MHFG before the business combination 72 101 The fair value of equity interests in DIAM held by MHFG before the business combination (¥72 billion) and the fair value of the 1,038,408 common shares of MHAM as the consideration paid for DIAM (¥29 billion) 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 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. On October 1, 2016, the MHFG Group recognized a gain of ¥56 billion 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 not included in the Group’s consolidated statements of income for the six months ended September 30, 2016. It will be included in Other noninterest income for the fiscal year ending March 31, 2017. Other than the gain of ¥56 billion 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 six months ended September 30, 2015 and 2016 if the business combination had occurred as of the beginning of the periods.

Basis of presentation (Policies

Basis of presentation (Policies)	6 Months Ended
	Sep. 30, 2016
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, through its subsidiaries (“the MHFG Group”, or “the Group”), provides domestic and international financial services in Japan and other countries. For a discussion of the Group’s segment information, see Note 20 “Business segment information”. The accompanying consolidated financial statements have been prepared in accordance with the accounting principles generally accepted in the United States of America (“U.S. GAAP”). The consolidated financial statements are stated in Japanese yen, the currency of the country in which MHFG is incorporated and principally operates. The accompanying consolidated financial statements include the accounts of MHFG and its subsidiaries. MHFG’s interim financial reporting period ends on September 30 and certain subsidiaries’ interim financial reporting period ends on June 30. The necessary adjustments have been made to the consolidated financial statements if significant transactions took place during the three-month period. When determining whether to consolidate investee entities, the MHFG Group performed a careful 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 unaudited consolidated financial statements should be read in conjunction with the audited financial statements and related notes thereto included in the annual financial statements for the fiscal year ended March 31, 2016. Certain financial information that is normally included in annual financial statements prepared in accordance with U.S. GAAP, but is not required for interim reporting purposes, has been condensed or omitted.
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

Investments (Tables)

Investments (Tables)	6 Months Ended
	Sep. 30, 2016
Amortized Cost Gross Unrealized Gains and Losses and Fair Value of Investments Table	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) March 31, 2016 Available-for-sale Debt securities: Japanese government bonds 15,672,171 91,420 1,015 15,762,576 Japanese local government bonds 234,587 6,097 3 240,681 U.S. Treasury bonds and federal agency securities 436,792 1,720 32 438,480 Other foreign government bonds 939,808 2,740 153 942,395 Agency mortgage-backed securities (1) 920,375 29,804 1,293 948,886 Residential mortgage-backed securities 206,882 4,254 878 210,258 Commercial mortgage-backed securities 186,525 788 523 186,790 Japanese corporate bonds and other debt securities (2) 2,079,599 15,688 420 2,094,867 Foreign corporate bonds and other debt securities (3) 839,981 8,744 1,421 847,304 Equity securities (marketable) 1,663,486 2,121,379 4,577 3,780,288 Total 23,180,206 2,282,634 10,315 25,452,525 Held-to-maturity Debt securities: Japanese government bonds 3,760,032 56,620 — 3,816,652 Agency mortgage-backed securities (4) 1,058,929 3,894 6,266 1,056,557 Total 4,818,961 60,514 6,266 4,873,209 September 30, 2016 Available-for-sale Debt securities: Japanese government bonds 10,322,825 52,600 4,836 10,370,589 Japanese local government bonds 274,890 6,449 28 281,311 U.S. Treasury bonds and federal agency securities 904,552 50 767 903,835 Other foreign government bonds 926,996 1,707 110 928,593 Agency mortgage-backed securities (1) 887,307 25,285 647 911,945 Residential mortgage-backed securities 166,837 3,165 688 169,314 Commercial mortgage-backed securities 197,481 998 300 198,179 Japanese corporate bonds and other debt securities (2) 2,071,260 37,099 1,394 2,106,965 Foreign corporate bonds and other debt securities (3) 789,496 6,387 1,072 794,811 Equity securities (marketable) 1,693,665 1,956,294 3,006 3,646,953 Total 18,235,309 2,090,034 12,848 20,312,495 Held-to-maturity Debt securities: Japanese government bonds 3,459,999 54,852 — 3,514,851 Agency mortgage-backed securities (4) 800,097 4,714 1,743 803,068 Total 4,260,096 59,566 1,743 4,317,919 Notes: (1) Agency mortgage-backed securities presented in the above table consist of U.S. agency securities and Japanese agency securities, of which the fair values were ¥168,604 million and ¥780,282 million, respectively, at March 31, 2016, and ¥167,585 million and ¥744,360 million, respectively, at September 30, 2016. U.S. agency securities primarily consist of Government National Mortgage Association (“Ginnie Mae”) securities, which are guaranteed by the United States government. All Japanese agency securities are mortgage-backed securities issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise. (2) Other debt securities presented in the above table primarily consist of certificates of deposit (“CDs”) and asset-backed securities (“ABS”), of which the total fair values were ¥158,446 million at March 31, 2016, and ¥146,851 million at September 30, 2016. (3) Other debt securities presented in the above table primarily consist of CDs, ABS, and collateralized loan obligations (“CLO”), of which the total fair values were ¥201,952 million at March 31, 2016, and ¥212,641 million at September 30, 2016. (4) All Agency mortgage-backed securities presented in the above table are Ginnie Mae securities.
Investments Classified by Contractual Maturity Date	Securities not due at a single maturity date and securities embedded with call or prepayment options, such as mortgage-backed securities, are included in the table below based on their contractual maturities. 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 1,396,343 7,400,210 1,462,976 63,296 10,322,825 Japanese local government bonds 33,648 99,991 140,591 660 274,890 U.S. Treasury bonds and federal agency securities 823,997 — 74,569 5,986 904,552 Other foreign government bonds 720,168 201,202 5,626 — 926,996 Agency mortgage-backed securities — — — 887,307 887,307 Residential mortgage-backed securities — — — 166,837 166,837 Commercial mortgage-backed securities 1,250 128,468 67,763 — 197,481 Japanese corporate bonds and other debt securities 406,988 1,088,491 399,102 176,679 2,071,260 Foreign corporate bonds and other debt securities 204,995 428,081 68,458 87,962 789,496 Total 3,587,389 9,346,443 2,219,085 1,388,727 16,541,644 Held-to-maturity Debt securities: Japanese government bonds 999,979 1,980,160 479,860 — 3,459,999 Agency mortgage-backed securities — — — 800,097 800,097 Total 999,979 1,980,160 479,860 800,097 4,260,096 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 1,396,500 7,432,623 1,478,096 63,370 10,370,589 Japanese local government bonds 33,716 101,444 145,352 799 281,311 U.S. Treasury bonds and federal agency securities 824,007 — 74,062 5,766 903,835 Other foreign government bonds 720,490 202,207 5,896 — 928,593 Agency mortgage-backed securities — — — 911,945 911,945 Residential mortgage-backed securities — — — 169,314 169,314 Commercial mortgage-backed securities 1,250 128,443 68,486 — 198,179 Japanese corporate bonds and other debt securities 407,503 1,095,194 403,617 200,651 2,106,965 Foreign corporate bonds and other debt securities 206,085 432,423 68,370 87,933 794,811 Total 3,589,551 9,392,334 2,243,879 1,439,778 16,665,542 Held-to-maturity Debt securities: Japanese government bonds 1,003,550 2,001,089 510,212 — 3,514,851 Agency mortgage-backed securities — — — 803,068 803,068 Total 1,003,550 2,001,089 510,212 803,068 4,317,919
Other-Than-Temporary Impairment on Available-for-Sale Securities	The following table shows the other-than-temporary impairment on available-for-sale held-to-maturity Six months ended September 30, 2015 2016 (in millions of yen) Available-for-sale Debt securities 40 56 Equity securities 6,060 10,016 Total 6,100 10,072
Unrealized Loss Position Investments	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) March 31, 2016 Available-for-sale Debt securities: Japanese government bonds 1,531,400 692 74,427 323 1,605,827 1,015 Japanese local government bonds 3,434 3 — — 3,434 3 U.S. Treasury bonds and federal agency securities 315,425 32 — — 315,425 32 Other foreign government bonds 225,493 139 225 14 225,718 153 Agency mortgage-backed securities (1) 15,965 86 58,147 1,207 74,112 1,293 Residential mortgage-backed securities 2,417 3 39,984 875 42,401 878 Commercial mortgage-backed securities 40,471 300 22,465 223 62,936 523 Japanese corporate bonds and other debt securities 360,782 348 20,109 72 380,891 420 Foreign corporate bonds and other debt securities 186,478 972 22,090 449 208,568 1,421 Equity securities (marketable) 71,262 4,515 180 62 71,442 4,577 Total 2,753,127 7,090 237,627 3,225 2,990,754 10,315 Held-to-maturity Debt securities: Agency mortgage-backed securities (2) 394,673 5,384 101,892 882 496,565 6,266 Total 394,673 5,384 101,892 882 496,565 6,266 September 30, 2016 Available-for-sale Debt securities: Japanese government bonds 2,112,158 4,391 90,433 445 2,202,591 4,836 Japanese local government bonds 8,182 28 — — 8,182 28 U.S. Treasury bonds and federal agency securities 190,983 767 — — 190,983 767 Other foreign government bonds 277,723 107 3,299 3 281,022 110 Agency mortgage-backed securities (1) 41,607 232 47,609 415 89,216 647 Residential mortgage-backed securities 7,037 8 35,004 680 42,041 688 Commercial mortgage-backed securities 22,635 117 32,620 183 55,255 300 Japanese corporate bonds and other debt securities 288,591 1,177 87,971 217 376,562 1,394 Foreign corporate bonds and other debt securities 130,937 699 53,956 373 184,893 1,072 Equity securities (marketable) 159,314 1,972 4,292 1,034 163,606 3,006 Total 3,239,167 9,498 355,184 3,350 3,594,351 12,848 Held-to-maturity Debt securities: Agency mortgage-backed securities (2) — — 280,284 1,743 280,284 1,743 Total — — 280,284 1,743 280,284 1,743 Notes: (1) Agency mortgage-backed securities presented in the above table consist of U.S. agency securities and Japanese agency securities, of which the fair values were ¥69,805 million and ¥4,307 million, respectively, at March 31, 2016, and ¥54,473 million and ¥34,743 million, respectively, at September 30, 2016. U.S. agency securities primarily consist of Ginnie Mae securities, which are guaranteed by the United States government. All Japanese agency securities are mortgage-backed securities issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise. (2) All Agency mortgage-backed securities presented in the above table are Ginnie Mae securities.
Realized Gains (Losses) on Sales of Available-for-Sale Securities	The following table shows the realized gains and losses on sales of available-for-sale available-for-sale Six months ended September 30, 2015 2016 (in millions of yen) Gross realized gains 128,495 144,796 Gross realized losses (14,949 ) (9,615 ) Net realized gains (losses) on sales of available-for-sale 113,546 135,181
Other Investments Disclosure	The following table summarizes the composition of Other investments at March 31, 2016 and September 30, 2016: March 31, 2016 September 30, 2016 (in millions of yen) Equity method investments 258,180 242,744 Investments held by consolidated investment companies 42,045 37,481 Other equity interests 313,221 300,629 Total 613,446 580,854

Loans (Tables)

Loans (Tables)	6 Months Ended
	Sep. 30, 2016
Schedule of Accounts, Notes, Loans and Financing Receivable	The table below presents loans outstanding by domicile and industry of borrower at March 31, 2016 and September 30, 2016: March 31, 2016 September 30, 2016 (in millions of yen) Domestic: Manufacturing 8,344,808 8,086,048 Construction and real estate 7,733,513 7,666,062 Services 4,655,704 4,560,155 Wholesale and retail 5,408,850 5,100,718 Transportation and communications 3,267,902 3,528,283 Banks and other financial institutions 3,632,481 3,579,276 Government and public institutions 3,395,784 5,682,739 Other industries (Note) 4,619,336 4,244,129 Individuals: Mortgage loans 10,589,646 10,241,326 Other 924,408 912,106 Total domestic 52,572,432 53,600,842 Foreign: Commercial and industrial 17,319,284 15,784,820 Banks and other financial institutions 6,382,449 6,022,059 Government and public institutions 1,174,665 921,697 Other (Note) 273,695 202,798 Total foreign 25,150,093 22,931,374 Total 77,722,525 76,532,216 Less: Unearned income and deferred loan fees—net 167,156 150,308 Total loans before allowance for loan losses 77,555,369 76,381,908 Note: Other industries of Domestic and Other of Foreign include trade receivables and lease receivables of consolidated VIEs.
Financing Receivable Credit Quality Indicators	The table below presents credit quality information of loans based on the MHFG Group’s internal rating system at March 31, 2016 and September 30, 2016: Normal obligors Watch obligors (1) A-B C-D Retail (2) Other (3) E1-E2 Retail (2) Other (3) Impaired Total (in millions of yen) March 31, 2016 Domestic: Manufacturing 4,859,256 2,681,958 103,343 148,102 163,213 12,473 2,958 373,505 8,344,808 Construction and real estate 3,956,798 2,709,617 601,251 157,057 215,244 16,408 255 76,883 7,733,513 Services 2,611,296 1,674,328 195,140 2,380 81,704 24,846 — 66,010 4,655,704 Wholesale and retail 2,240,228 2,552,552 223,677 57,865 147,404 39,486 546 147,092 5,408,850 Transportation and communications 2,410,967 695,697 86,094 380 35,090 10,518 — 29,156 3,267,902 Banks and other financial institutions 2,719,047 881,405 2,234 3,788 22,303 264 — 3,440 3,632,481 Government and public institutions 3,181,241 4,047 — 210,496 — — — — 3,395,784 Other industries 1,954,222 685,258 3,501 1,929,712 7,053 329 35,315 3,946 4,619,336 Individuals — 259,646 10,891,538 107,131 34,744 96,729 1,659 122,607 11,514,054 Total domestic 23,933,055 12,144,508 12,106,778 2,616,911 706,755 201,053 40,733 822,639 52,572,432 Foreign: Total foreign 15,540,347 5,748,131 8,382 3,132,856 472,696 10 80,607 167,064 25,150,093 Total 39,473,402 17,892,639 12,115,160 5,749,767 1,179,451 201,063 121,340 989,703 77,722,525 September 30, 2016 Domestic: Manufacturing 4,821,589 2,511,839 94,614 114,648 152,447 12,020 3,768 375,123 8,086,048 Construction and real estate 4,038,679 2,662,926 580,874 101,261 199,136 16,775 384 66,027 7,666,062 Services 2,591,663 1,617,784 186,542 1,495 71,778 25,071 51 65,771 4,560,155 Wholesale and retail 2,158,490 2,368,145 205,881 32,117 145,727 37,476 281 152,601 5,100,718 Transportation and communications 2,682,877 688,034 84,095 205 43,046 9,691 — 20,335 3,528,283 Banks and other financial institutions 2,698,093 842,036 1,812 554 30,461 385 — 5,935 3,579,276 Government and public institutions 4,802,983 3,750 — 876,006 — — — — 5,682,739 Other industries 1,865,412 574,973 3,253 1,753,107 5,154 402 34,224 7,604 4,244,129 Individuals — 271,561 10,561,515 79,597 31,722 92,621 1,413 115,003 11,153,432 Total domestic 25,659,786 11,541,048 11,718,586 2,958,990 679,471 194,441 40,121 808,399 53,600,842 Foreign: Total foreign 14,474,511 5,101,484 9,116 2,695,051 428,832 9 72,470 149,901 22,931,374 Total 40,134,297 16,642,532 11,727,702 5,654,041 1,108,303 194,450 112,591 958,300 76,532,216 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) Amounts represent small balance, homogeneous loans which are subject to pool allocations. (3) Non-impaired
Impaired Financing Receivables	The table below presents impaired loans information at March 31, 2016 and September 30, 2016: Recorded investment (1) Requiring Not (2) Total Unpaid Related (3) Average Interest (4) (in millions of yen) March 31, 2016 Domestic: Manufacturing 365,361 8,144 373,505 379,642 138,676 410,491 7,930 Construction and real estate 59,883 17,000 76,883 87,516 10,130 89,075 1,246 Services 56,695 9,315 66,010 72,603 19,095 69,525 1,292 Wholesale and retail 134,425 12,667 147,092 157,215 46,304 149,324 2,376 Transportation and communications 25,665 3,491 29,156 30,497 5,694 33,119 630 Banks and other financial institutions 3,390 50 3,440 3,440 1,095 5,188 42 Other industries 3,591 355 3,946 4,132 799 2,665 64 Individuals 63,367 59,240 122,607 135,325 6,085 133,015 2,058 Total domestic 712,377 110,262 822,639 870,370 227,878 892,402 15,638 Foreign: Total foreign 148,471 18,593 167,064 180,870 61,308 186,440 2,629 Total 860,848 128,855 989,703 1,051,240 289,186 1,078,842 18,267 Recorded investment (1) Requiring Not (2) Total Unpaid Related (3) Average Interest (4) (in millions of yen) September 30, 2016 Domestic: Manufacturing 367,787 7,336 375,123 381,412 141,908 374,314 1,404 Construction and real estate 51,468 14,559 66,027 75,170 7,712 71,455 572 Services 58,030 7,741 65,771 72,960 19,725 65,890 604 Wholesale and retail 141,135 11,466 152,601 161,702 50,449 149,847 1,222 Transportation and communications 16,508 3,827 20,335 21,376 4,567 24,746 215 Banks and other financial institutions 3,072 2,863 5,935 5,935 1,055 4,687 30 Other industries 7,543 61 7,604 7,790 2,277 5,775 43 Individuals 57,061 57,942 115,003 126,924 5,886 118,805 967 Total domestic 702,604 105,795 808,399 853,269 233,579 815,519 5,057 Foreign: Total foreign 134,395 15,506 149,901 163,841 59,433 158,482 888 Total 836,999 121,301 958,300 1,017,110 293,012 974,001 5,945 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 small balance, homogeneous loans totaling ¥347,839 million and ¥330,764 million as of March 31, 2016 and September 30, 2016 which were collectively evaluated for impairment, in addition to the allowance for those that were individually evaluated for impairment. (4) Amounts represent gross interest income on impaired loans which were included in Interest income on loans in the consolidated statements of income.
Troubled Debt Restructurings on Financing Receivables by Type of Restructuring	The following table presents TDRs that were entered into during the six months ended September 30, 2015 and 2016: Loan forgiveness or debt to equity swaps Interest rate reduction Recorded investment (Note) Charge-offs (in millions of yen) September 30, 2015 Domestic: Manufacturing 67,058 34,081 60,865 Construction and real estate — — 15,059 Services — — 23,345 Wholesale and retail — — 77,097 Transportation and communications 49 279 12,230 Banks and other financial institutions — — 4,776 Other industries — — 2,933 Individuals — — 17,066 Total domestic 67,107 34,360 213,371 Foreign: Total foreign — — 23,971 Total 67,107 34,360 237,342 September 30, 2016 Domestic: Manufacturing — — 54,476 Construction and real estate — — 8,596 Services — — 21,951 Wholesale and retail — — 87,237 Transportation and communications — — 8,656 Banks and other financial institutions — — 3,198 Other industries — — 2,274 Individuals — — 9,205 Total domestic — — 195,593 Foreign: Total foreign — — 10,849 Total — — 206,442 Note: Amounts represent the book values of loans immediately after the restructurings.
Troubled Debt Restructurings on Financing Receivables Subsequently Defaulted	The following table presents payment defaults which occurred during the six months ended September 30, 2015 and 2016 with respect to the loans modified as TDRs within the previous twelve months: Recorded investment September 30, 2015 September 30, 2016 (in millions of yen) Domestic: Manufacturing 2,890 1,801 Construction and real estate 1,731 1,621 Services 2,710 1,188 Wholesale and retail 13,097 4,614 Transportation and communications 833 771 Individuals 2,068 1,366 Total domestic 23,329 11,361 Foreign: Total foreign 6,901 30 Total 30,230 11,391
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, 2016 and September 30, 2016: 30-59 days 60-89 days 90 days or Total past Current Total (in millions of yen) March 31, 2016 Domestic: Manufacturing 1,555 163 9,454 11,172 8,333,636 8,344,808 Construction and real estate 2,713 1,024 35,691 39,428 7,694,085 7,733,513 Services 2,479 223 7,016 9,718 4,645,986 4,655,704 Wholesale and retail 3,193 886 8,861 12,940 5,395,910 5,408,850 Transportation and communications 594 81 2,033 2,708 3,265,194 3,267,902 Banks and other financial institutions — — — — 3,632,481 3,632,481 Government and public institutions — — — — 3,395,784 3,395,784 Other industries — — 29 29 4,619,307 4,619,336 Individuals 38,682 13,570 38,413 90,665 11,423,389 11,514,054 Total domestic 49,216 15,947 101,497 166,660 52,405,772 52,572,432 Foreign: Total foreign 859 2,598 30,000 33,457 25,116,636 25,150,093 Total 50,075 18,545 131,497 200,117 77,522,408 77,722,525 September 30, 2016 Domestic: Manufacturing 1,467 41 11,060 12,568 8,073,480 8,086,048 Construction and real estate 2,449 1,488 35,538 39,475 7,626,587 7,666,062 Services 1,030 572 8,046 9,648 4,550,507 4,560,155 Wholesale and retail 1,561 681 6,914 9,156 5,091,562 5,100,718 Transportation and communications 279 — 2,039 2,318 3,525,965 3,528,283 Banks and other financial institutions 16 — — 16 3,579,260 3,579,276 Government and public institutions — — — — 5,682,739 5,682,739 Other industries 41 14 28 83 4,244,046 4,244,129 Individuals 38,201 10,375 38,490 87,066 11,066,366 11,153,432 Total domestic 45,044 13,171 102,115 160,330 53,440,512 53,600,842 Foreign: Total foreign 35,917 1,251 43,508 80,676 22,850,698 22,931,374 Total 80,961 14,422 145,623 241,006 76,291,210 76,532,216

Allowance for loan losses (Tabl

Allowance for loan losses (Tables)	6 Months Ended
	Sep. 30, 2016
Allowance for Credit Losses on Financing Receivables	Changes in Allowance for loan losses by portfolio segment for the six months ended September 30, 2015 and 2016 are shown below: Corporate Retail Other Total (in millions of yen) Six months ended September 30, 2015 Balance at beginning of period 423,177 60,469 36,613 520,259 Provision (credit) for loan losses 6,878 (10,052 ) 6,204 3,030 Charge-offs (59,795 ) (1,251 ) (6,173 ) (67,219 ) Recoveries 7,733 634 1,375 9,742 Net charge-offs (52,062 ) (617 ) (4,798 ) (57,477 ) Others (Note) (971 ) — 197 (774 ) Balance at end of period 377,022 49,800 38,216 465,038 Six months ended September 30, 2016 Balance at beginning of period 367,739 44,221 39,287 451,247 Provision (credit) for loan losses 9,123 (7,983 ) (571 ) 569 Charge-offs (10,332 ) (1,016 ) (3,812 ) (15,160 ) Recoveries 8,877 4,725 2,139 15,741 Net charge-offs (1,455 ) 3,709 (1,673 ) 581 Others (Note) (10,404 ) — (4,813 ) (15,217 ) Balance at end of period 365,003 39,947 32,230 437,180 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, 2016 and September 30, 2016: Corporate Retail Other Total (in millions of yen) March 31, 2016 Allowance for loan losses 367,739 44,221 39,287 451,247 of which individually evaluated for impairment 222,591 3,829 12,521 238,941 of which collectively evaluated for impairment 145,148 40,392 26,766 212,306 Loans (Note) 59,385,962 12,414,453 5,922,110 77,722,525 of which individually evaluated for impairment 634,049 24,768 63,280 722,097 of which collectively evaluated for impairment 58,751,913 12,389,685 5,858,830 77,000,428 September 30, 2016 Allowance for loan losses 365,003 39,947 32,230 437,180 of which individually evaluated for impairment 226,809 3,441 10,803 241,053 of which collectively evaluated for impairment 138,194 36,506 21,427 196,127 Loans (Note) 58,704,366 12,017,580 5,810,270 76,532,216 of which individually evaluated for impairment 598,269 24,472 62,043 684,784 of which collectively evaluated for impairment 58,106,097 11,993,108 5,748,227 75,847,432 Note: Amounts represent loan balances before deducting unearned income and deferred loan fees.

Other assets and liabilities (T

Other assets and liabilities (Tables)	6 Months Ended
	Sep. 30, 2016
Schedule of Other Assets and Other Liabilities	The following table sets forth the details of other assets and liabilities at March 31, 2016 and September 30, 2016: March 31, 2016 September 30, 2016 (in millions of yen) Other assets: Accounts receivable from brokers, dealers and customers for securities transactions 1,718,769 1,772,693 Collateral provided for derivative transactions 884,651 1,021,305 Prepaid pension cost 612,102 638,596 Miscellaneous receivables 286,896 266,944 Margins provided for futures contracts 225,240 190,893 Security deposits 113,066 112,218 Loans held for sale 33,133 35,024 Other 823,033 837,087 Total 4,696,890 4,874,760 Other liabilities: Accounts payable to brokers, dealers and customers for securities transactions 2,882,824 2,907,787 Collateral accepted for derivative transactions 715,894 979,152 Guaranteed trust principal 623,904 651,254 Miscellaneous payables 442,352 408,148 Margins accepted for futures contracts 334,925 328,362 Factoring amounts owed to customers 242,392 164,629 Unearned income 144,903 134,618 Other 1,089,529 1,067,604 Total 6,476,723 6,641,554

Preferred and common stock (Tab

Preferred and common stock (Tables)	6 Months Ended
	Sep. 30, 2016
Preferred stock
Schedule of Stock by Class	The composition of preferred stock at March 31, 2016 and September 30, 2016 is as follows: March 31, 2016 Aggregate amount Number of shares Class of stock Authorized Issued In treasury (in millions of yen) Eleventh series class XI preferred stock (1) 914,752 914,752,000 914,752,000 815,828,400 First series class XIV preferred stock (2) — 900,000,000 — — Second series class XIV preferred stock (2) — 900,000,000 — — Third series class XIV preferred stock (2) — 900,000,000 — — Fourth series class XIV preferred stock (2) — 900,000,000 — — First series class XV preferred stock (3) — 900,000,000 — — Second series class XV preferred stock (3) — 900,000,000 — — Third series class XV preferred stock (3) — 900,000,000 — — Fourth series class XV preferred stock (3) — 900,000,000 — — First series class XVI preferred stock (4) — 1,500,000,000 — — Second series class XVI preferred stock (4) — 1,500,000,000 — — Third series class XVI preferred stock (4) — 1,500,000,000 — — Fourth series class XVI preferred stock (4) — 1,500,000,000 — — Total 914,752 4,214,752,000 914,752,000 815,828,400 September 30, 2016 Aggregate amount Number of shares Class of stock Authorized Issued In treasury (in millions of yen) Class XI preferred stock — 914,752,000 — — First series class XIV preferred stock (2) — 900,000,000 — — Second series class XIV preferred stock (2) — 900,000,000 — — Third series class XIV preferred stock (2) — 900,000,000 — — Fourth series class XIV preferred stock (2) — 900,000,000 — — First series class XV preferred stock (3) — 900,000,000 — — Second series class XV preferred stock (3) — 900,000,000 — — Third series class XV preferred stock (3) — 900,000,000 — — Fourth series class XV preferred stock (3) — 900,000,000 — — First series class XVI preferred stock (4) — 1,500,000,000 — — Second series class XVI preferred stock (4) — 1,500,000,000 — — Third series class XVI preferred stock (4) — 1,500,000,000 — — Fourth series class XVI preferred stock (4) — 1,500,000,000 — — Total — 4,214,752,000 — — Notes: (1) The aggregate amount and number of issued shares include the preferred stock in treasury which has been converted into common stock but not yet cancelled. (2) The total number of authorized shares from first to fourth series class XIV preferred stock shall not exceed 900,000,000. (3) The total number of authorized shares from first to fourth series class XV preferred stock shall not exceed 900,000,000. (4) The total number of authorized shares from first to fourth series class XVI preferred stock shall not exceed 1,500,000,000.

Dividends (Tables)

Dividends (Tables)	6 Months Ended
	Sep. 30, 2016
Schedule of Dividends Payable	The following table shows dividends on preferred stock and common stock during the six months ended September 30, 2015 and 2016: September 30, 2015 Cash dividends Class of stock Per share In aggregate (in yen) (in millions of yen) Eleventh series class XI preferred stock 10 2,131 Common stock 4 98,453 Total 100,584 September 30, 2016 Cash dividends Class of stock Per share In aggregate (in yen) (in millions of yen) Eleventh series class XI preferred stock 10 989 Common stock 3.75 93,839 Total 94,828

Accumulated other comprehensi36

Accumulated other comprehensive income (Tables)	6 Months Ended
	Sep. 30, 2016
Changes in Each Component of Accumulated Other Comprehensive Income, Net Of Tax (AOCI)	Changes in each component of Accumulated other comprehensive income, net of tax (“AOCI”) for the six months ended September 30, 2015 and 2016 are as follows: Six months ended September 30, 2015 2016 (in millions of yen) AOCI, balance at beginning of period, previously reported 2,041,005 1,469,308 Cumulative effect of change in accounting principles (Notes 2 and 16) — 330 AOCI, balance at beginning of period, adjusted 2,041,005 1,469,638 Net unrealized gains (losses) on available-for-sale Balance at beginning of period, previously reported 1,747,607 1,409,459 Cumulative effect of change in accounting principles — (85 ) Balance at beginning of period, adjusted 1,747,607 1,409,374 Unrealized holding gains (losses) during period (179,849 ) (49,362 ) Less: reclassification adjustments for losses (gains) included in net income (72,860 ) (86,761 ) Change during period (252,709 ) (136,123 ) Balance at end of period 1,494,898 1,273,251 Foreign currency translation adjustments: Balance at beginning of period, previously reported 129,179 6,310 Cumulative effect of change in accounting principles — 415 Balance at beginning of period, adjusted 129,179 6,725 Foreign currency translation adjustments during period (43,121 ) (59,893 ) Less: reclassification adjustments for losses (gains) included in net income — — Change during period (43,121 ) (59,893 ) Balance at end of period 86,058 (53,168 ) Pension liability adjustments: Balance at beginning of period 164,219 53,539 Unrealized gains (losses) during period 1,314 533 Less: reclassification adjustments for losses (gains) included in net income (1,554 ) 144 Change during period (240 ) 677 Balance at end of period 163,979 54,216 Total other comprehensive income (loss), net of tax attributable to MHFG shareholders (296,070 ) (195,339 ) AOCI, balance at end of period 1,744,935 1,274,299
Amounts Reclassified Out of Accumulated Other Comprehensive Income into Net Income	The following table shows the amounts reclassified out of AOCI into net income during the six months ended September 30, 2016: Six months ended September 30, 2016 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 125,109 (38,351 ) 86,758 3 86,761 Investment gains (losses)—net Pension liability adjustments (233 ) 87 (146 ) 2 (144 ) Salaries and employee benefits Total 124,876 (38,264 ) 86,612 5 86,617 Notes: (1) The amounts in the Before tax column are recorded in each account presented under the heading “Affected line items in the consolidated statements of income”. (2) The amounts in the Tax effect column and Net of tax attributable to noncontrolling interests column are recorded in Income tax expense and Net income attributable to noncontrolling interests in the consolidated statements of income, respectively.

Regulatory matters (Tables)

Regulatory matters (Tables)	6 Months Ended
	Sep. 30, 2016
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations	Capital adequacy ratios of MHFG, MHBK, and MHTB as of March 31, 2016 and September 30, 2016 calculated in accordance with Japanese GAAP and guidelines established by the Financial Services Agency are set forth in the following table: March 31, 2016 September 30, 2016 Amount Ratio Amount Ratio (in billions of yen, except percentages) Consolidated: MHFG: Common Equity Tier 1 capital: Required (Note) 3,361 5.375 3,314 5.375 Actual 6,566 10.50 6,769 10.98 Tier 1 capital: Required (Note) 4,299 6.875 4,238 6.875 Actual 7,905 12.64 7,983 12.94 Total risk-based capital: Required (Note) 5,550 8.875 5,471 8.875 Actual 9,639 15.41 9,768 15.84 MHBK: Common Equity Tier 1 capital: Required 2,555 4.50 2,532 4.50 Actual 6,142 10.81 6,202 11.02 Tier 1 capital: Required 3,406 6.00 3,376 6.00 Actual 7,244 12.75 7,440 13.22 Total risk-based capital: Required 4,542 8.00 4,501 8.00 Actual 8,780 15.46 9,012 16.01 MHTB: Common Equity Tier 1 capital: Required 109 4.50 108 4.50 Actual 440 18.21 452 18.80 Tier 1 capital: Required 145 6.00 144 6.00 Actual 440 18.21 452 18.80 Total risk-based capital: Required 193 8.00 192 8.00 Actual 472 19.52 479 19.95 Non-consolidated: MHBK: Common Equity Tier 1 capital: Required 2,489 4.50 2,431 4.50 Actual 5,892 10.65 5,977 11.06 Tier 1 capital: Required 3,318 6.00 3,242 6.00 Actual 7,004 12.66 7,239 13.39 Total risk-based capital: Required 4,424 8.00 4,323 8.00 Actual 8,576 15.50 8,846 16.37 MHTB: Common Equity Tier 1 capital: Required 109 4.50 109 4.50 Actual 448 18.52 462 19.05 Tier 1 capital: Required 145 6.00 145 6.00 Actual 448 18.52 462 19.05 Total risk-based capital: Required 194 8.00 194 8.00 Actual 480 19.80 489 20.16 Note: The required amounts and ratios as of March 31, 2016 and September 30, 2016 include those equivalent to a transition capital conservation buffer of 0.625% and transition additional loss absorbency requirements for a global systemically important bank (“G-SIB”) (“D-SIB”)

Earnings per common share (Tabl

Earnings per common share (Tables)	6 Months Ended
	Sep. 30, 2016
Schedule of Calculation of Numerator and Denominator in Earnings Per Share	The following table sets forth the computation of basic and diluted earnings per common share for the six months ended September 30, 2015 and 2016: Six months ended 2015 2016 (in millions of yen) Net income: Net income attributable to MHFG shareholders 365,873 379,558 Less: Net income attributable to preferred shareholders 1,441 — Net income attributable to common shareholders 364,432 379,558 Effect of dilutive securities: Convertible preferred stock 1,441 — Net income attributable to common shareholders after assumed conversions 365,873 379,558 Six months ended 2015 2016 (thousands of shares) Shares: Weighted average common shares outstanding 24,718,566 25,204,801 Effect of dilutive securities: Convertible preferred stock (Note) 649,240 165,533 Stock options 18,467 11,997 Weighted average common shares after assumed conversions 25,386,273 25,382,331 Six months ended 2015 2016 (in yen) Amounts per common share: Basic net income per common share 14.74 15.06 Diluted net income per common share 14.41 14.95 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)	6 Months Ended
	Sep. 30, 2016
Schedule of Components of Income Tax Expense (Benefit)	The following table presents the components of Income tax expense for the six months ended September 30, 2015 and 2016: Six months ended September 30, 2015 2016 (in millions of yen) Current tax expense 137,371 102,390 Deferred tax expense (benefit) 29,890 (27,875 ) Total income tax expense 167,261 74,515
Comprehensive Income Tax (Expense) Benefit Components	The detailed amounts recorded directly in Equity are as follows: Six months ended September 30, 2015 2016 (in millions of yen) Net unrealized gains (losses) on available-for-sale Unrealized gains (losses) (86,790 ) (21,562 ) Less: reclassification adjustments (34,567 ) (38,351 ) Total (121,357 ) (59,913 ) Foreign currency translation adjustments: Unrealized gains (losses) — (126 ) Less: reclassification adjustments — — Total — (126 ) Pension liability adjustments: Unrealized gains (losses) (118 ) 239 Less: reclassification adjustments (692 ) 87 Total (810 ) 326 Total tax effect before allocation to noncontrolling interests (122,167 ) (59,713 )

Pension and other employee be40

Pension and other employee benefit plans (Tables)	6 Months Ended
	Sep. 30, 2016
Components of Net Periodic Benefit Costs	The following table summarizes the components of net periodic benefit cost of the severance indemnities and pension plans of the MHFG Group for the six months ended September 30, 2015 and 2016: Six months ended September 30, 2015 2016 (in millions of yen) Service cost-benefits earned during the period 17,803 22,219 Interest costs on projected benefit obligations 6,242 2,716 Expected return on plan assets (20,177 ) (17,860 ) Amortization of prior service benefits (97 ) (97 ) Amortization of net actuarial loss (gain) (2,049 ) 385 Special termination benefits 2,212 1,744 Net periodic benefit cost 3,934 9,107

Derivative financial instrume41

Derivative financial instruments (Tables)	6 Months Ended
	Sep. 30, 2016
Schedule of Derivative Instruments	The following table summarizes the notional and fair value amounts of derivative instruments outstanding as of March 31, 2016 and September 30, 2016. The fair values of 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 master netting agreements in the consolidated balance sheets, or the table below. Fair value Derivative receivables (2) Derivative payables (2) March 31, 2016 Notional amount (1) Designated as Not designated Designated as Not designated (in billions of yen) Interest rate contracts 1,066,252 — 11,522 — 11,269 Foreign exchange contracts 141,517 4 3,126 1 2,979 Equity-related contracts 3,115 18 152 — 140 Credit-related contracts 4,826 — 43 — 37 Other contracts 327 — 59 — 55 Total 1,216,037 22 14,902 1 14,480 Fair value Derivative receivables (2) Derivative payables (2) September 30, 2016 Notional amount (1) Designated as Not designated Designated as Not designated (in billions of yen) Interest rate contracts 986,753 — 13,767 — 13,339 Foreign exchange contracts 134,265 6 3,127 — 2,730 Equity-related contracts 3,982 16 137 — 152 Credit-related contracts 4,164 — 31 — 32 Other contracts 317 — 45 — 41 Total 1,129,481 22 17,107 — 16,294 Notes: (1) Notional amount includes the sum of gross long and gross short third-party contracts. (2) Derivative receivables and payables are recorded in Trading account assets and Trading account liabilities, respectively.
Disclosure of Credit Derivatives	The following table summarizes the notional and fair value amounts of credit derivatives at March 31, 2016 and September 30, 2016: March 31, 2016 September 30, 2016 Notional amount Fair value Notional amount Fair value (in billions of yen) Credit protection written: Investment grade 1,603 14 1,678 23 Non-investment 763 1 414 3 Total 2,366 15 2,092 26 Credit protection purchased 2,592 (9 ) 2,225 (27 ) 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
Notional And Credit Risk Amounts Of Outstanding Derivative Positions Disclosure	The following table shows the maximum potential amount of future payments for credit protection written by expiration period at March 31, 2016 and September 30, 2016: Maximum payout/Notional amount March 31, 2016 September 30, 2016 (in billions of yen) One year or less 538 492 After one year through five years 1,729 1,336 After five years 99 264 Total 2,366 2,092 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.
Schedule Of Derivative Instruments Value Including Credit Risk Related Contingent Features Table	The following table shows the quantitative information about derivative instruments with credit-risk-related contingent features at March 31, 2016 and September 30, 2016: March 31, 2016 September 30, 2016 (in billions of yen) Aggregate fair value of derivative instruments with credit-risk-related contingent features in net liability positions 790 815 Collateral provided to counterparties in normal course of business 746 775 Amount required to be posted as collateral or settled immediately if credit-risk-related contingent features were triggered 44 40
Designated as Hedging Instrument | Fair Value Hedging
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 six months ended September 30, 2015 and 2016: Gains (losses) recorded in income Six months ended September 30, 2015 Derivatives Hedged Hedge Net gain (loss) excluded (in millions of yen) Equity-related contracts 13,450 (14,798 ) — (1,348 ) Total 13,450 (14,798 ) — (1,348 ) Gains (losses) recorded in income Six months ended September 30, 2016 Derivatives Hedged Hedge Net gain (loss) excluded (in millions of yen) Equity-related contracts 6,002 (7,807 ) — (1,805 ) Total 6,002 (7,807 ) — (1,805 )
Designated as Hedging Instrument | Net Investment Hedging
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 six months ended September 30, 2015 and 2016: Gains (losses) recorded in income and other comprehensive income (“OCI”) 2015 2016 Effective portion Ineffective portion Effective portion Ineffective portion (in millions of yen) Financial instruments hedging foreign exchange risk 723 200 107,528 890 Total 723 200 107,528 890 Note: No amount related to the effective portion of net investment hedges was reclassified from Accumulated other comprehensive income to earnings for the six months ended September 30, 2015 and 2016, respectively.
Not Designated as Hedging Instrument
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance	The following table summarizes gains and losses on derivatives not designated or qualifying as hedges during the six months ended September 30, 2015 and 2016: Gains (losses) recorded in income 2015 2016 (in millions of yen) Interest rate contracts 150,748 80,040 Foreign exchange contracts (4,453 ) 11,173 Equity-related contracts (1) 10,268 11,049 Credit-related contracts (2) (8,419 ) (4,827 ) Other contracts 451 564 Total 148,595 97,999 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 gain (loss) of ¥3,531 million and ¥(5,698) million on the credit derivatives hedging the credit risk of loans during the six months ended September 30, 2015 and 2016, respectively.

Commitments and contingencies (

Commitments and contingencies (Tables)	6 Months Ended
	Sep. 30, 2016
Schedule of Guarantor Obligations	The maximum potential amount of future payments disclosed below represents the contractual amounts that could be required to be repaid in the event of the guarantees being executed, without consideration of possible recoveries under recourse provisions or from collateral held. With respect to written options included in derivative financial instruments in the table below, in theory, the MHFG Group is exposed to unlimited losses; therefore, the table shows the notional amounts of the contracts as a substitute for the maximum exposure. March 31, September 30, (in billions of yen) Performance guarantees 2,110 2,065 Guarantees on loans 297 252 Guarantees on securities 203 176 Other guarantees 1,571 1,559 Guarantees for the repayment of trust principal 1,141 433 Liabilities of trust accounts 12,747 13,828 Derivative financial instruments 15,792 15,264
Schedule of Off Balance Sheet Commitments and Guarantees	The table below summarizes the contractual amounts with regard to these undrawn commitments at March 31, 2016 and September 30, 2016: March 31, September 30, (in billions of yen) Commitments to extend credit (Note) 75,742 72,946 Commercial letters of credit 448 428 Total 76,190 73,374 Note: Commitments to extend credit include commitments to invest in securities.
Performance guarantees, Guarantees on loans, Guarantees on securities and Other guarantees
Schedule of Guarantor Obligations	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, 2016 and September 30, 2016: March 31, September 30, (in billions of yen) Investment grade 3,160 3,075 Non-investment 1,022 977 Total 4,182 4,052 Note: Investment grade in the internal rating scale generally corresponds to BBB- or above in the external rating scale.

Variable interest entities an43

Variable interest entities and securitizations (Tables)	6 Months Ended
	Sep. 30, 2016
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, 2016 and September 30, 2016: Assets on balance sheets related to unconsolidated VIEs: March 31, September 30, (in billions of yen) Trading account assets 55 70 Investments 254 348 Loans 205 210 Total 514 628 Liabilities on balance sheets and maximum exposure to loss related to unconsolidated VIEs: March 31, September 30, (in billions of yen) Payables under securities lending transactions 27 27 Trading account liabilities 1 1 Total 28 28 Maximum exposure to loss (Note) 534 684 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
Unconsolidated VIEs
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, 2016 and September 30, 2016: Consolidated VIEs Significant March 31, 2016 Consolidated assets Total assets Maximum (in billions of yen) Asset-backed commercial paper/loan programs 2,092 — — Asset-backed securitizations 579 205 13 Investments in securitization products 337 445 154 Investment funds 1,660 2,422 367 Trust arrangements and other 24 — — Total 4,692 3,072 534 Consolidated VIEs Significant September 30, 2016 Consolidated assets Total assets Maximum (in billions of yen) Asset-backed commercial paper/loan programs 1,860 — — Asset-backed securitizations 677 199 7 Investments in securitization products 336 445 154 Investment funds 1,726 3,589 523 Trust arrangements and other 23 — — Total 4,622 4,233 684

Fair value (Tables)

Fair value (Tables)	6 Months Ended
	Sep. 30, 2016
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	Assets and liabilities measured at fair value on a recurring basis at March 31, 2016 and September 30, 2016, including those for which the MHFG Group has elected the fair value option, are summarized below: March 31, 2016 Level 1 Level 2 Level 3 Assets/ (in billions of yen) Assets: Trading securities (1) Japanese government bonds 2,272 31 — 2,303 Japanese local government bonds — 79 — 79 U.S. Treasury bonds and federal agency securities 3,729 77 — 3,806 Other foreign government bonds 2,192 373 — 2,565 Agency mortgage-backed securities 995 563 — 1,558 Residential mortgage-backed securities — — 21 21 Commercial mortgage-backed securities — 2 2 4 Certificates of deposit and commercial paper — 881 — 881 Corporate bonds and other 9 1,693 720 2,422 Equity securities 758 62 21 841 Trading securities measured at net asset value (2) 617 Derivatives: Interest rate contracts 97 11,396 29 11,522 Foreign exchange contracts 23 3,099 8 3,130 Equity-related contracts 46 95 29 170 Credit-related contracts — 40 3 43 Other contracts — 21 38 59 Available-for-sale Japanese government bonds 15,037 726 — 15,763 Japanese local government bonds — 241 — 241 U.S. Treasury bonds and federal agency securities 438 — — 438 Other foreign government bonds 352 590 — 942 Agency mortgage-backed securities 169 780 — 949 Residential mortgage-backed securities — 87 123 210 Commercial mortgage-backed securities — — 187 187 Japanese corporate bonds and other debt securities — 1,921 174 2,095 Foreign corporate bonds and other debt securities — 739 108 847 Equity securities (marketable) 3,716 — — 3,716 Available-for-sale (2) 65 Other investments — — 42 42 Total assets measured at fair value on a recurring basis 29,833 23,496 1,505 55,516 Liabilities: Trading securities sold, not yet purchased 2,482 148 — 2,630 Derivatives: Interest rate contracts 98 11,168 3 11,269 Foreign exchange contracts 26 2,953 1 2,980 Equity-related contracts 60 56 24 140 Credit-related contracts — 33 4 37 Other contracts — 18 37 55 Long-term debt (3) — 433 623 1,056 Total liabilities measured at fair value on a recurring basis 2,666 14,809 692 18,167 September 30, 2016 Level 1 Level 2 Level 3 Assets/ (in billions of yen) Assets: Trading securities (1) Japanese government bonds 2,404 17 — 2,421 Japanese local government bonds — 51 — 51 U.S. Treasury bonds and federal agency securities 2,930 96 — 3,026 Other foreign government bonds 1,697 335 — 2,032 Agency mortgage-backed securities 1,381 572 — 1,953 Residential mortgage-backed securities — — 17 17 Commercial mortgage-backed securities — 2 — 2 Certificates of deposit and commercial paper — 617 — 617 Corporate bonds and other 5 1,303 976 2,284 Equity securities 767 60 18 845 Trading securities measured at net asset value (2) 576 Derivatives: Interest rate contracts 70 13,672 25 13,767 Foreign exchange contracts 24 3,102 7 3,133 Equity-related contracts 42 90 21 153 Credit-related contracts — 28 3 31 Other contracts 1 8 36 45 Available-for-sale Japanese government bonds 9,624 747 — 10,371 Japanese local government bonds — 281 — 281 U.S. Treasury bonds and federal agency securities 904 — — 904 Other foreign government bonds 374 555 — 929 Agency mortgage-backed securities 168 744 — 912 Residential mortgage-backed securities — 69 100 169 Commercial mortgage-backed securities — — 198 198 Japanese corporate bonds and other debt securities — 1,931 176 2,107 Foreign corporate bonds and other debt securities — 688 107 795 Equity securities (marketable) 3,552 — — 3,552 Available-for-sale (2) 95 Other investments — — 37 37 Total assets measured at fair value on a recurring basis 23,943 24,968 1,721 51,303 Liabilities: Trading securities sold, not yet purchased 2,422 253 1 2,676 Derivatives: Interest rate contracts 73 13,263 3 13,339 Foreign exchange contracts 19 2,710 1 2,730 Equity-related contracts 62 59 31 152 Credit-related contracts — 29 3 32 Other contracts — 6 35 41 Long-term debt (3) — 939 591 1,530 Total liabilities measured at fair value on a recurring basis 2,576 17,259 665 20,500 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 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, 2016 and September 30, 2016 were ¥30 billion and ¥28 billion, respectively. (3) Amounts represent items for which the Group elected the fair value option.
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	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 six months ended September 30, 2015 and 2016: Six months ended September 30, 2015 April 1, Gains Gains Transfers Transfers Purchases Sales Issuances Settle- September 30, Change in (losses) (6) (in billions of yen) Assets: Trading securities: Other foreign government bonds — — (2) — — — 1 (1 ) — — — — Residential mortgage-backed securities 29 — (2) — — — — — — (5 ) 24 — Commercial mortgage-backed securities 4 — (2) — — — — — — (1 ) 3 — Corporate bonds and other 639 (4 ) (2) — 8 (20 ) 233 (88 ) — (40 ) 728 (5 ) Equity securities 23 (2 ) (2) — — — — (1 ) — — 20 (2 ) Derivatives, net (1) Interest rate contracts 18 (6 ) (2) — — — — — — 6 18 (5 ) Foreign exchange contracts 8 4 (2) — — — — — — (4 ) 8 (1 ) Equity-related contracts (14 ) 15 (2) — — — — — — — 1 12 Credit-related contracts (1 ) — (2) — — — — — — 1 — — Available-for-sale Residential mortgage-backed securities 166 — (3) — (4) — — — (4 ) — (22 ) 140 — Commercial mortgage-backed securities 169 — (3) — (4) — — 56 (37 ) — (5 ) 183 — Japanese corporate bonds and other debt securities 155 1 (3) 7 (4) — — 55 (3 ) — (23 ) 192 — Foreign corporate bonds and other debt securities 85 1 (3) (6 ) (4) 23 — 37 — — (23 ) 117 — Other investments 53 8 (3) — — — 1 (19 ) — (2 ) 41 (7 ) Liabilities: Trading securities sold, not yet purchased — — (2) — — — (1 ) 1 — — — — Long-term debt 587 27 (5) — 1 (1 ) — — 160 (139 ) 581 27 Six months ended September 30, 2016 April 1, Gains Gains Transfers Transfers Purchases Sales Issuances Settle- September 30, Change in (losses) (6) (in billions of yen) Assets: Trading securities: Residential mortgage-backed securities 21 — (2) — — — — — — (4 ) 17 — Commercial mortgage-backed securities 2 — (2) — — — — — — (2 ) — — Corporate bonds and 720 (53 ) (2) — 280 (2 ) 343 (241 ) — (71 ) 976 (39 ) Equity securities 21 4 (2) — — — — (7 ) — — 18 4 Derivatives, net (1) Interest rate contracts 26 (4 ) (2) — — — — — — — 22 (3 ) Foreign exchange contracts 7 6 (2) — — — — — — (7 ) 6 — Equity-related contracts 5 (13 ) (2) — — — — — — (2 ) (10 ) (19 ) Credit-related contracts (1 ) 1 (2) — — — — — — — — — Other contracts 1 — (2) — — — — — — — 1 — Available-for-sale Residential mortgage-backed securities 123 — (3) — (4) — — — (1 ) — (22 ) 100 — Commercial mortgage-backed securities 187 — (3) — (4) — — 20 — — (9 ) 198 — Japanese corporate bonds and other debt securities 174 — (3) 22 (4) — — 1 (4 ) — (17 ) 176 — Foreign corporate bonds and other debt securities 108 1 (3) (7 ) (4) — — 10 — — (5 ) 107 — Other investments 42 (3 ) (3) — — — 11 — — (13 ) 37 (1 ) Liabilities: Trading securities sold, not yet purchased — — (2) — 1 — (32 ) 32 — — 1 — Long-term debt 623 9 (5) — — (12 ) — — 147 (158 ) 591 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 September 30, 2015 and 2016.
Quantitative Information About Level Three 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, 2016 and September 30, 2016: March 31, 2016 Products/Instruments Fair value Principal valuation technique Unobservable inputs Range of input values Weighted average (5) (in billions of yen, except for ratios and basis points) Trading securities and Available-for-sale Residential mortgage-backed securities 144 Discounted cash flow Price-based Prepayment rate Default rate Recovery rate Discount margin 3% - 19% 0% - 2% 100% - 100% 13bps - 180bps 7% 0% 100% 60bps Commercial mortgage-backed securities 189 Discounted cash flow Price-based Discount margin 6bps - 580bps 37bps Corporate bonds and other debt securities 1,002 Discounted cash flow Price-based Prepayment rate (1) Default rate (1) Recovery rate (1) Discount margin (1) Discount margin (2) 0% - 21% 0% - 2% 60% - 69% 11bps - 1,115bps 10bps - 3,850bps 19% 2% 68% 151bps 454bps Derivatives, net: Interest rate contracts 26 Internal valuation model (3) IR – IR correlation Default rate (4) 32% - 100% 0% - 63% Foreign exchange contracts 7 Internal valuation model (3) FX – IR correlation FX – FX correlation Default rate (4) 5% - 50% 54% - 54% 0% - 63% Equity-related contracts 5 Internal valuation model (3) Equity – IR correlation Equity – FX correlation Equity volatility 30% - 30% 55% - 55% 10% - 40% Credit-related contracts (1 ) Internal valuation model (3) Default rate Credit correlation 0% - 42% 29% - 100% Long-term debt 623 Internal valuation model (3) IR – IR correlation FX – IR correlation FX – FX correlation Equity – IR correlation Equity – FX correlation Equity correlation Equity volatility Default rate Credit correlation 32% - 100% 5% - 50% 54% - 54% 30% - 30% 55% - 55% 18% - 100% 14% - 39% 0% - 5% 28% - 100% September 30, 2016 Products/Instruments Fair value Principal valuation technique Unobservable inputs Range of input values Weighted average (5) (in billions of yen, except for ratios and basis points) Trading securities and Available-for-sale Residential mortgage-backed securities 117 Discounted cash flow Price-based Prepayment rate Default rate Recovery rate Discount margin 3% - 19% 0% - 2% 100% - 100% 15bps - 170bps 7% 0% 100% 59bps Commercial mortgage-backed securities 198 Discounted cash flow Price-based Discount margin 4bps - 184bps 30bps Corporate bonds and other debt securities 1,259 Discounted cash flow Price-based Prepayment rate (1) (1) Recovery rate (1) Discount margin (1) 14% - 23% 1% - 2% 60% - 69% 13bps - 1,109bps 22% 2% 68% 133bps Discount margin (2) -32bps - 2,987bps 422bps Derivatives, net: Interest rate contracts 22 Internal valuation model (3) IR – IR correlation Default rate (4) 23% - 100% 0% - 63% Foreign exchange contracts 6 Internal valuation model (3) FX – IR correlation FX – FX correlation Default rate (4) 1% - 50% 55% - 55% 0% - 63% Equity-related contracts (10 ) Internal valuation model (3) Equity – IR correlation Equity – FX correlation Equity volatility 25% - 25% 55% - 55% 6% - 48% Credit-related contracts — Internal valuation model (3) Default rate Credit correlation 0% - 59% 28% - 100% Long-term debt 591 Internal valuation model (3) IR – IR correlation FX – IR correlation FX – FX correlation Equity – IR correlation Equity – FX correlation Equity correlation Equity volatility Default rate Credit correlation 23% - 100% 1% - 50% 55% - 55% 25% - 25% 55% - 55% 18% - 100% 7% - 42% 0% - 3% 34% - 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
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis	The following table shows the fair value hierarchy for these items as of March 31, 2016 and September 30, 2016: March 31, 2016 Total Level 1 Level 2 Level 3 Aggregate cost (in billions of yen) Assets: Loans 124 — — 124 197 Loans held-for-sale 13 — 7 6 14 Other investments 1 — — 1 2 Premises and equipment—net — — — — 1 Goodwill — — — — 6 Total assets measured at fair value on a nonrecurring basis 138 — 7 131 220 September 30, 2016 Total Level 1 Level 2 Level 3 Aggregate cost (in billions of yen) Assets: Loans 118 — — 118 185 Loans held-for-sale 4 — 4 — 4 Other investments 5 4 — 1 9 Total assets measured at fair value on a nonrecurring basis 127 4 4 119 198
Fair Value, by Balance Sheet Grouping	The following table shows the carrying amounts and fair values at March 31, 2016 and September 30, 2016, 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”) : March 31, 2016 Carrying Estimated fair value Total Level 1 Level 2 Level 3 (in billions of yen) Financial assets: Cash and due from banks, call loans and funds sold, and receivables under resale agreements and securities borrowing transactions 48,757 48,757 923 47,834 — Investments 4,819 4,873 4,873 — — Loans, net of allowance for loan losses (Note) 77,040 78,241 — — 78,241 Financial liabilities: Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions 39,908 39,908 17,223 22,685 — Interest-bearing deposits 100,228 100,234 46,207 54,027 — Due to trust accounts 4,467 4,467 — 4,467 — Other short-term borrowings 2,080 2,080 — 2,080 — Long-term debt 13,691 13,863 — 12,969 894 September 30, 2016 Carrying Estimated fair value Total Level 1 Level 2 Level 3 (in billions of yen) Financial assets: Cash and due from banks, call loans and funds sold, and receivables under resale agreements and securities borrowing transactions 56,658 56,658 942 55,716 — Investments 4,260 4,318 4,318 — — Loans, net of allowance for loan losses (Note) 75,821 76,945 — — 76,945 Financial liabilities: Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions 39,580 39,580 17,948 21,632 — Interest-bearing deposits 101,793 101,803 47,587 54,216 — Due to trust accounts 3,425 3,425 — 3,425 — Other short-term borrowings 1,556 1,556 — 1,556 — Long-term debt 13,709 13,865 — 12,950 915 Note: Loans, net of allowance for loan losses include items measured at fair value on a nonrecurring basis.

Offsetting of financial asset45

Offsetting of financial assets and financial liabilities (Tables)	6 Months Ended
	Sep. 30, 2016
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, 2016 and September 30, 2016. 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 (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) March 31, 2016 Assets (1) Derivatives 14,130 — 14,130 (12,167 ) (599 ) 1,364 Receivables under resale agreements 7,490 — 7,490 (7,461 ) — 29 Receivables under securities borrowing transactions 3,327 — 3,327 (3,318 ) — 9 Total 24,947 — 24,947 (22,946 ) (599 ) 1,402 Liabilities (1) Derivatives 13,652 — 13,652 (12,043 ) (748 ) 861 Payables under repurchase agreements 16,507 — 16,507 (16,464 ) — 43 Payables under securities lending transactions 2,538 — 2,538 (2,531 ) — 7 Total 32,697 — 32,697 (31,038 ) (748 ) 911 September 30, 2016 Assets (1) Derivatives 15,916 — 15,916 (13,562 ) (709 ) 1,645 Receivables under resale agreements 9,068 — 9,068 (9,028 ) — 40 Receivables under securities borrowing transactions 3,060 — 3,060 (3,046 ) — 14 Total 28,044 — 28,044 (25,636 ) (709 ) 1,699 Liabilities (1) Derivatives 15,152 — 15,152 (13,471 ) (910 ) 771 Payables under repurchase agreements 17,250 — 17,250 (17,142 ) — 108 Payables under securities lending transactions 1,188 — 1,188 (1,180 ) — 8 Total 33,590 — 33,590 (31,793 ) (910 ) 887 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 sec46

Repurchase agreements and securities lending transactions accounted for as secured borrowings (Tables)	6 Months Ended
	Sep. 30, 2016
Gross Amounts of Liabilities Associated with Repurchase Agreements and Securities Lending Transactions, 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, 2016 and September 30, 2016: Overnight and Up to 30 days 31-90 days Greater than 90 Total (in billions of yen) March 31, 2016 Repurchase agreements 6,289 6,125 3,582 837 16,833 Securities lending transactions 1,909 700 — 236 2,845 Total 8,198 6,825 3,582 1,073 19,678 September 30, 2016 Repurchase agreements 327 12,847 3,362 1,203 17,739 Securities lending transactions 182 1,133 — 220 1,535 Total 509 13,980 3,362 1,423 19,274
Gross Amounts of Liabilities Associated with Repurchase Agreements and Securities Lending Transactions 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, 2016 and September 30, 2016: Repurchase Securities lending (in billions of yen) March 31, 2016 Japanese government bonds and Japanese local government bonds 532 1,891 Foreign government bonds and foreign agency mortgage-backed securities 15,781 700 Commercial paper and corporate bonds 221 27 Equity securities 141 185 Other 158 42 Total (Note) 16,833 2,845 September 30, 2016 Japanese government bonds and Japanese local government bonds 634 717 Foreign government bonds and foreign agency mortgage-backed securities 16,087 579 Commercial paper and corporate bonds 486 29 Equity securities 380 182 Other 152 28 Total (Note) 17,739 1,535 Note: Amounts exceeded the gross amounts recognized in Note 18 “Offsetting of financial assets and financial liabilities” by ¥633 billion and ¥836 billion, at March 31, 2016 and September 30, 2016, 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)	6 Months Ended
	Sep. 30, 2016
Schedule of Segment Reporting Information, by Segment	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 each business segment’s net business profits with income before income tax expense under U.S. GAAP. Management does not use information on business segment’s assets to allocate resources and assess performance and has not prepared information on the segment’s assets. Accordingly, information on the segment’s assets is not available. MHFG (Consolidated) Six months ended September 30, 2015 (1) Retail & Corporate & Global Global Asset Others (3) Total (in billions of yen) Gross profits 332.1 209.5 204.8 332.3 26.6 26.5 1,131.8 General and administrative expenses 331.1 91.3 111.6 88.5 15.0 34.8 672.3 Others — — — — — (12.8 ) (12.8 ) Net business profits (losses) (2) 1.0 118.2 93.2 243.8 11.6 (21.1 ) 446.7 MHFG (Consolidated) Six months ended September 30, 2016 Retail & Corporate & Global Global Asset Others (3) Total (in billions of yen) Gross profits 310.8 223.2 192.7 334.3 24.5 4.2 1,089.7 General and administrative expenses 338.8 92.9 115.5 94.6 15.0 23.7 680.5 Others — — — — — (6.0 ) (6.0 ) Net business profits (losses) (2) (28.0 ) 130.3 77.2 239.7 9.5 (25.5 ) 403.2 Notes: (1) Following the introduction of an in-house (2) Net business profits is used in Japan as a measure of the profitability of core banking operations, and is defined as gross profits (or the sum of net interest income, fiduciary income, net fee and commission income, net trading income and net other operating income) less general and administrative expenses. 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.
Reconciliation of Operating Profit (Loss) from Segments to Consolidated	A reconciliation of total net business profits under the internal management reporting systems for the six months ended September 30, 2015 and 2016 presented above to income before income tax expense shown on the consolidated statements of income is as follows: Six months ended September 30, 2015 2016 (in billions of yen) Net business profits 446.7 403.2 U.S. GAAP adjustments (67.6 ) 14.8 (Provision) credit for loan losses (3.0 ) (0.6 ) Net gains (losses) related to equity investments 122.6 64.5 Non-recurring (0.8 ) (4.7 ) Gains on disposal of premises and equipment 8.8 3.5 (Provision) credit for losses on off-balance-sheet 9.3 7.9 Others—net 26.5 (31.3 ) Income before income tax expense 542.5 457.3

Subsequent events (Tables)

Subsequent events (Tables)	6 Months Ended
	Sep. 30, 2016
Summary of Consideration Paid	The following table summarizes the consideration paid for DIAM. Since the MHFG Group is currently calculating the amounts recognized at the acquisition date for each major class of acquired assets and assumed liabilities as well as the fair value at the acquisition date of the noncontrolling interest in DIAM, such information could not be included in the consolidated financial statements. There were no material acquisition-related costs that were recognized separately from the acquisitions of the assets and the assumptions of the liabilities. At October 1, (in billions of yen) Consideration Equity instruments (1,038,408 common shares of MHAM) 29 Fair value of total consideration transferred 29 Fair value of equity interests in DIAM held by MHFG before the business combination 72 101

Recently Issued Accounting Pr49

Recently Issued Accounting Pronouncements - Additional Information (Detail) - ASU No. 2015-02 ¥ in Millions	Sep. 30, 2016JPY (¥)
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principles, net of tax	¥ (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	¥ 330

Investments (Amortized Cost Gro

Investments (Amortized Cost Gross Unrealized Gains and Losses and Fair Value of Available-for-Sale and Held-to-Maturity Securities) (Detail) - JPY (¥) ¥ in Millions		Sep. 30, 2016	Mar. 31, 2016
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities		¥ 18,235,309	¥ 23,180,206
Gross unrealized gains, available-for-sale securities		2,090,034	2,282,634
Gross unrealized losses, available-for-sale securities		12,848	10,315
Fair value, available-for-sale securities		20,312,495	25,452,525
Amortized cost, held-to-maturity securities		4,260,096	4,818,961
Gross unrealized gains, held-to-maturity securities		59,566	60,514
Gross unrealized losses, held-to-maturity securities		1,743	6,266
Fair value, held-to-maturity securities		4,317,919	4,873,209
Debt securities | Agency mortgage-backed securities
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities	[1]	887,307	920,375
Gross unrealized gains, available-for-sale securities	[1]	25,285	29,804
Gross unrealized losses, available-for-sale securities	[1],[2]	647	1,293
Fair value, available-for-sale securities	[1]	911,945	948,886
Amortized cost, held-to-maturity securities	[3]	800,097	1,058,929
Gross unrealized gains, held-to-maturity securities	[3]	4,714	3,894
Gross unrealized losses, held-to-maturity securities	[3]	1,743	6,266
Fair value, held-to-maturity securities	[3]	803,068	1,056,557
Debt securities | Japanese government bonds
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities		10,322,825	15,672,171
Gross unrealized gains, available-for-sale securities		52,600	91,420
Gross unrealized losses, available-for-sale securities		4,836	1,015
Fair value, available-for-sale securities		10,370,589	15,762,576
Amortized cost, held-to-maturity securities		3,459,999	3,760,032
Gross unrealized gains, held-to-maturity securities		54,852	56,620
Fair value, held-to-maturity securities		3,514,851	3,816,652
Debt securities | Japanese local government bonds
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities		274,890	234,587
Gross unrealized gains, available-for-sale securities		6,449	6,097
Gross unrealized losses, available-for-sale securities		28	3
Fair value, available-for-sale securities		281,311	240,681
Debt securities | U.S. Treasury bonds and federal agency securities
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities		904,552	436,792
Gross unrealized gains, available-for-sale securities		50	1,720
Gross unrealized losses, available-for-sale securities		767	32
Fair value, available-for-sale securities		903,835	438,480
Debt securities | Other foreign government bonds
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities		926,996	939,808
Gross unrealized gains, available-for-sale securities		1,707	2,740
Gross unrealized losses, available-for-sale securities		110	153
Fair value, available-for-sale securities		928,593	942,395
Debt securities | Residential mortgage-backed securities
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities		166,837	206,882
Gross unrealized gains, available-for-sale securities		3,165	4,254
Gross unrealized losses, available-for-sale securities		688	878
Fair value, available-for-sale securities		169,314	210,258
Debt securities | Commercial mortgage-backed securities
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities		197,481	186,525
Gross unrealized gains, available-for-sale securities		998	788
Gross unrealized losses, available-for-sale securities		300	523
Fair value, available-for-sale securities		198,179	186,790
Debt securities | Japanese corporate bonds and other debt securities
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities	[4]	2,071,260	2,079,599
Gross unrealized gains, available-for-sale securities	[4]	37,099	15,688
Gross unrealized losses, available-for-sale securities	[4]	1,394	420
Fair value, available-for-sale securities	[4]	2,106,965	2,094,867
Debt securities | Foreign corporate bonds and other debt securities
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities	[5]	789,496	839,981
Gross unrealized gains, available-for-sale securities	[5]	6,387	8,744
Gross unrealized losses, available-for-sale securities	[5]	1,072	1,421
Fair value, available-for-sale securities	[5]	794,811	847,304
Equity securities (marketable)
Schedule of Investments [Line Items]
Amortized cost, available-for-sale securities		1,693,665	1,663,486
Gross unrealized gains, available-for-sale securities		1,956,294	2,121,379
Gross unrealized losses, available-for-sale securities		3,006	4,577
Fair value, available-for-sale securities		¥ 3,646,953	¥ 3,780,288
[1]	Agency mortgage-backed securities presented in the above table consist of U.S. agency securities and Japanese agency securities, of which the fair values were ¥168,604 million and ¥780,282 million, respectively, at March 31, 2016, and ¥167,585 million and ¥744,360 million, respectively, at September 30, 2016. U.S. agency securities primarily consist of Government National Mortgage Association ("Ginnie Mae") securities, which are guaranteed by the United States government. All Japanese agency securities are mortgage-backed securities issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise.
[2]	Agency mortgage-backed securities presented in the above table consist of U.S. agency securities and Japanese agency securities, of which the fair values were ¥69,805 million and ¥4,307 million, respectively, at March 31, 2016, and ¥54,473 million and ¥34,743 million, respectively, at September 30, 2016. U.S. agency securities primarily consist of Ginnie Mae securities, which are guaranteed by the United States government. All Japanese agency securities are mortgage-backed securities issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise.
[3]	All Agency mortgage-backed securities presented in the above table are Ginnie Mae securities.
[4]	Other debt securities presented in the above table primarily consist of certificates of deposit ("CDs") and asset-backed securities ("ABS"), of which the total fair values were ¥158,446 million at March 31, 2016, and ¥146,851 million at September 30, 2016.
[5]	Other debt securities presented in the above table primarily consist of CDs, ABS, and collateralized loan obligations ("CLO"), of which the total fair values were ¥201,952 million at March 31, 2016, and ¥212,641 million at September 30, 2016.

Investments (Amortized Cost G51

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		Sep. 30, 2016	Mar. 31, 2016
Schedule of Investments [Line Items]
Fair value, available-for-sale securities		¥ 20,312,495	¥ 25,452,525
Agency mortgage-backed securities | Debt securities
Schedule of Investments [Line Items]
Fair value, available-for-sale securities	[1]	911,945	948,886
Certificates of deposit ("CDs") and Asset-Backed Securities ("ABS") | Japanese government and corporate debt securities
Schedule of Investments [Line Items]
Fair value, available-for-sale securities		146,851	158,446
CDs, ABS, and collateral loan obligations ("CLO") | Foreign government and corporate debt securities
Schedule of Investments [Line Items]
Fair value, available-for-sale securities		212,641	201,952
U.S. agency securities | Agency mortgage-backed securities | Debt securities
Schedule of Investments [Line Items]
Fair value, available-for-sale securities		167,585	168,604
Japanese agency securities | Agency mortgage-backed securities | Debt securities
Schedule of Investments [Line Items]
Fair value, available-for-sale securities		¥ 744,360	¥ 780,282
[1]	Agency mortgage-backed securities presented in the above table consist of U.S. agency securities and Japanese agency securities, of which the fair values were ¥168,604 million and ¥780,282 million, respectively, at March 31, 2016, and ¥167,585 million and ¥744,360 million, respectively, at September 30, 2016. U.S. agency securities primarily consist of Government National Mortgage Association ("Ginnie Mae") securities, which are guaranteed by the United States government. All Japanese agency securities are mortgage-backed securities issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise.

Investments (Amortized Cost and

Investments (Amortized Cost and Fair Value of Available-for-sale and Held-to-maturity Debt Securities by Contractual Maturity) (Detail) - JPY (¥) ¥ in Millions		Sep. 30, 2016	Mar. 31, 2016
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost		¥ 3,587,389
Due after one year through five years, amortized cost		9,346,443
Due after five years through ten years,amortized cost		2,219,085
Due after ten years, amortized cost		1,388,727
Total		16,541,644
Due in one year or less, amortized cost		999,979
Due after one year through five years, amortized cost		1,980,160
Due after five years through ten years, amortized cost		479,860
Due after ten years, amortized cost		800,097
Amortized cost, held-to-maturity securities		4,260,096	¥ 4,818,961
Due in one year or less, fair value		3,589,551
Due after one year through five years, fair value		9,392,334
Due after five years through ten years, fair value		2,243,879
Due after ten years, fair value		1,439,778
Total		16,665,542
Due in one year or less, fair value		1,003,550
Due after one year through five years, fair value		2,001,089
Due after five years through ten years, fair value		510,212
Due after ten years, fair value		803,068
Total		4,317,919	4,873,209
Debt securities | Japanese government bonds
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost		1,396,343
Due after one year through five years, amortized cost		7,400,210
Due after five years through ten years,amortized cost		1,462,976
Due after ten years, amortized cost		63,296
Total		10,322,825
Due in one year or less, amortized cost		999,979
Due after one year through five years, amortized cost		1,980,160
Due after five years through ten years, amortized cost		479,860
Amortized cost, held-to-maturity securities		3,459,999	3,760,032
Due in one year or less, fair value		1,396,500
Due after one year through five years, fair value		7,432,623
Due after five years through ten years, fair value		1,478,096
Due after ten years, fair value		63,370
Total		10,370,589
Due in one year or less, fair value		1,003,550
Due after one year through five years, fair value		2,001,089
Due after five years through ten years, fair value		510,212
Total		3,514,851	3,816,652
Debt securities | Agency mortgage-backed securities
Investments Classified by Contractual Maturity Date [Line Items]
Due after ten years, amortized cost		887,307
Total		887,307
Due after ten years, amortized cost		800,097
Amortized cost, held-to-maturity securities	[1]	800,097	1,058,929
Due after ten years, fair value		911,945
Total		911,945
Due after ten years, fair value		803,068
Total	[1]	803,068	¥ 1,056,557
Debt securities | Japanese local government bonds
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost		33,648
Due after one year through five years, amortized cost		99,991
Due after five years through ten years,amortized cost		140,591
Due after ten years, amortized cost		660
Total		274,890
Due in one year or less, fair value		33,716
Due after one year through five years, fair value		101,444
Due after five years through ten years, fair value		145,352
Due after ten years, fair value		799
Total		281,311
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		823,997
Due after five years through ten years,amortized cost		74,569
Due after ten years, amortized cost		5,986
Total		904,552
Due in one year or less, fair value		824,007
Due after five years through ten years, fair value		74,062
Due after ten years, fair value		5,766
Total		903,835
Debt securities | Other foreign government bonds
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost		720,168
Due after one year through five years, amortized cost		201,202
Due after five years through ten years,amortized cost		5,626
Total		926,996
Due in one year or less, fair value		720,490
Due after one year through five years, fair value		202,207
Due after five years through ten years, fair value		5,896
Total		928,593
Debt securities | Residential mortgage-backed securities
Investments Classified by Contractual Maturity Date [Line Items]
Due after ten years, amortized cost		166,837
Total		166,837
Due after ten years, fair value		169,314
Total		169,314
Debt securities | Commercial mortgage-backed securities
Investments Classified by Contractual Maturity Date [Line Items]
Due in one year or less, amortized cost		1,250
Due after one year through five years, amortized cost		128,468
Due after five years through ten years,amortized cost		67,763
Total		197,481
Due in one year or less, fair value		1,250
Due after one year through five years, fair value		128,443
Due after five years through ten years, fair value		68,486
Total		198,179
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		406,988
Due after one year through five years, amortized cost		1,088,491
Due after five years through ten years,amortized cost		399,102
Due after ten years, amortized cost		176,679
Total		2,071,260
Due in one year or less, fair value		407,503
Due after one year through five years, fair value		1,095,194
Due after five years through ten years, fair value		403,617
Due after ten years, fair value		200,651
Total		2,106,965
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		204,995
Due after one year through five years, amortized cost		428,081
Due after five years through ten years,amortized cost		68,458
Due after ten years, amortized cost		87,962
Total		789,496
Due in one year or less, fair value		206,085
Due after one year through five years, fair value		432,423
Due after five years through ten years, fair value		68,370
Due after ten years, fair value		87,933
Total		¥ 794,811
[1]	All Agency mortgage-backed securities presented in the above table are Ginnie Mae securities.

Investments - Additional Inform

Investments - Additional Information (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Mar. 31, 2016
Gain (Loss) on Investments [Line Items]
Equity method Investments, carrying value	¥ 242,744		¥ 258,180
Held-to-maturity Securities
Gain (Loss) on Investments [Line Items]
Impairment loss on securities	¥ 0	¥ 0
Orient Corporation
Gain (Loss) on Investments [Line Items]
Percentage of proportionate share to the total outstanding common shares	49.00%
Equity securities (marketable)
Gain (Loss) on Investments [Line Items]
Equity method Investments, carrying value	¥ 120,256		124,830
Equity method Investments, aggregated market values	¥ 234,754		¥ 277,508

Investments (Other-Than-Tempora

Investments (Other-Than-Temporary Impairment on Available-for-Sale Securities) (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment on available-for-sale securities	¥ 10,072	¥ 6,100
Debt securities
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment on available-for-sale securities	56	40
Equity securities
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment on available-for-sale securities	¥ 10,016	¥ 6,060

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 Continuous Unrealized Loss Position (Detail) - JPY (¥) ¥ in Millions		Sep. 30, 2016	Mar. 31, 2016
Gain (Loss) on Investments [Line Items]
Less than 12 months, Fair value, available-for-sale securities		¥ 3,239,167	¥ 2,753,127
Less than 12 months Gross unrealized losses, available-for-sale securities		9,498	7,090
12 months or more Fair value, available-for-sale securities		355,184	237,627
12 months or more Gross unrealized losses, available-for-sale securities		3,350	3,225
Total Fair value, available-for-sale securities		3,594,351	2,990,754
Total Gross unrealized losses, available-for-sale securities		12,848	10,315
Less than 12 months, Fair value, held-to-maturity securities			394,673
Less than 12 months Gross unrealized losses, held-to-maturity securities			5,384
12 months or more Fair value, held-to-maturity securities		280,284	101,892
12 months or more Gross unrealized losses, held-to-maturity securities		1,743	882
Total Fair value, held-to-maturity securities		280,284	496,565
Total Gross unrealized losses, held-to-maturity securities		1,743	6,266
Debt securities | Agency mortgage-backed securities
Gain (Loss) on Investments [Line Items]
Less than 12 months, Fair value, available-for-sale securities	[1]	41,607	15,965
Less than 12 months Gross unrealized losses, available-for-sale securities	[1]	232	86
12 months or more Fair value, available-for-sale securities	[1]	47,609	58,147
12 months or more Gross unrealized losses, available-for-sale securities	[1]	415	1,207
Total Fair value, available-for-sale securities	[1]	89,216	74,112
Total Gross unrealized losses, available-for-sale securities	[1],[2]	647	1,293
Less than 12 months, Fair value, held-to-maturity securities	[3]		394,673
Less than 12 months Gross unrealized losses, held-to-maturity securities	[3]		5,384
12 months or more Fair value, held-to-maturity securities	[3]	280,284	101,892
12 months or more Gross unrealized losses, held-to-maturity securities	[3]	1,743	882
Total Fair value, held-to-maturity securities	[3]	280,284	496,565
Total Gross unrealized losses, held-to-maturity securities	[3]	1,743	6,266
Debt securities | Japanese government bonds
Gain (Loss) on Investments [Line Items]
Less than 12 months, Fair value, available-for-sale securities		2,112,158	1,531,400
Less than 12 months Gross unrealized losses, available-for-sale securities		4,391	692
12 months or more Fair value, available-for-sale securities		90,433	74,427
12 months or more Gross unrealized losses, available-for-sale securities		445	323
Total Fair value, available-for-sale securities		2,202,591	1,605,827
Total Gross unrealized losses, available-for-sale securities		4,836	1,015
Debt securities | Japanese local government bonds
Gain (Loss) on Investments [Line Items]
Less than 12 months, Fair value, available-for-sale securities		8,182	3,434
Less than 12 months Gross unrealized losses, available-for-sale securities		28	3
Total Fair value, available-for-sale securities		8,182	3,434
Total Gross unrealized losses, available-for-sale securities		28	3
Debt securities | U.S. Treasury bonds and federal agency securities
Gain (Loss) on Investments [Line Items]
Less than 12 months, Fair value, available-for-sale securities		190,983	315,425
Less than 12 months Gross unrealized losses, available-for-sale securities		767	32
Total Fair value, available-for-sale securities		190,983	315,425
Total Gross unrealized losses, available-for-sale securities		767	32
Debt securities | Other foreign government bonds
Gain (Loss) on Investments [Line Items]
Less than 12 months, Fair value, available-for-sale securities		277,723	225,493
Less than 12 months Gross unrealized losses, available-for-sale securities		107	139
12 months or more Fair value, available-for-sale securities		3,299	225
12 months or more Gross unrealized losses, available-for-sale securities		3	14
Total Fair value, available-for-sale securities		281,022	225,718
Total Gross unrealized losses, available-for-sale securities		110	153
Debt securities | Residential mortgage-backed securities
Gain (Loss) on Investments [Line Items]
Less than 12 months, Fair value, available-for-sale securities		7,037	2,417
Less than 12 months Gross unrealized losses, available-for-sale securities		8	3
12 months or more Fair value, available-for-sale securities		35,004	39,984
12 months or more Gross unrealized losses, available-for-sale securities		680	875
Total Fair value, available-for-sale securities		42,041	42,401
Total Gross unrealized losses, available-for-sale securities		688	878
Debt securities | Commercial mortgage-backed securities
Gain (Loss) on Investments [Line Items]
Less than 12 months, Fair value, available-for-sale securities		22,635	40,471
Less than 12 months Gross unrealized losses, available-for-sale securities		117	300
12 months or more Fair value, available-for-sale securities		32,620	22,465
12 months or more Gross unrealized losses, available-for-sale securities		183	223
Total Fair value, available-for-sale securities		55,255	62,936
Total Gross unrealized losses, available-for-sale securities		300	523
Debt securities | Japanese corporate bonds and other debt securities
Gain (Loss) on Investments [Line Items]
Less than 12 months, Fair value, available-for-sale securities		288,591	360,782
Less than 12 months Gross unrealized losses, available-for-sale securities		1,177	348
12 months or more Fair value, available-for-sale securities		87,971	20,109
12 months or more Gross unrealized losses, available-for-sale securities		217	72
Total Fair value, available-for-sale securities		376,562	380,891
Total Gross unrealized losses, available-for-sale securities	[4]	1,394	420
Debt securities | Foreign corporate bonds and other debt securities
Gain (Loss) on Investments [Line Items]
Less than 12 months, Fair value, available-for-sale securities		130,937	186,478
Less than 12 months Gross unrealized losses, available-for-sale securities		699	972
12 months or more Fair value, available-for-sale securities		53,956	22,090
12 months or more Gross unrealized losses, available-for-sale securities		373	449
Total Fair value, available-for-sale securities		184,893	208,568
Total Gross unrealized losses, available-for-sale securities	[5]	1,072	1,421
Equity securities (marketable)
Gain (Loss) on Investments [Line Items]
Less than 12 months, Fair value, available-for-sale securities		159,314	71,262
Less than 12 months Gross unrealized losses, available-for-sale securities		1,972	4,515
12 months or more Fair value, available-for-sale securities		4,292	180
12 months or more Gross unrealized losses, available-for-sale securities		1,034	62
Total Fair value, available-for-sale securities		163,606	71,442
Total Gross unrealized losses, available-for-sale securities		¥ 3,006	¥ 4,577
[1]	Agency mortgage-backed securities presented in the above table consist of U.S. agency securities and Japanese agency securities, of which the fair values were ¥69,805 million and ¥4,307 million, respectively, at March 31, 2016, and ¥54,473 million and ¥34,743 million, respectively, at September 30, 2016. U.S. agency securities primarily consist of Ginnie Mae securities, which are guaranteed by the United States government. All Japanese agency securities are mortgage-backed securities issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise.
[2]	Agency mortgage-backed securities presented in the above table consist of U.S. agency securities and Japanese agency securities, of which the fair values were ¥168,604 million and ¥780,282 million, respectively, at March 31, 2016, and ¥167,585 million and ¥744,360 million, respectively, at September 30, 2016. U.S. agency securities primarily consist of Government National Mortgage Association ("Ginnie Mae") securities, which are guaranteed by the United States government. All Japanese agency securities are mortgage-backed securities issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise.
[3]	All Agency mortgage-backed securities presented in the above table are Ginnie Mae securities.
[4]	Other debt securities presented in the above table primarily consist of certificates of deposit ("CDs") and asset-backed securities ("ABS"), of which the total fair values were ¥158,446 million at March 31, 2016, and ¥146,851 million at September 30, 2016.
[5]	Other debt securities presented in the above table primarily consist of CDs, ABS, and collateralized loan obligations ("CLO"), of which the total fair values were ¥201,952 million at March 31, 2016, and ¥212,641 million at September 30, 2016.

Investments (Gross Unrealized56

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 Continuous Unrealized Loss Position (Parenthetical) (Detail) - JPY (¥) ¥ in Millions		Sep. 30, 2016	Mar. 31, 2016
Gain (Loss) on Investments [Line Items]
Fair value, available-for-sale securities		¥ 3,594,351	¥ 2,990,754
Agency mortgage-backed securities | Debt securities
Gain (Loss) on Investments [Line Items]
Fair value, available-for-sale securities	[1]	89,216	74,112
U.S. agency securities | Agency mortgage-backed securities | Debt securities
Gain (Loss) on Investments [Line Items]
Fair value, available-for-sale securities		54,473	69,805
Japanese agency securities | Agency mortgage-backed securities | Debt securities
Gain (Loss) on Investments [Line Items]
Fair value, available-for-sale securities		¥ 34,743	¥ 4,307
[1]	Agency mortgage-backed securities presented in the above table consist of U.S. agency securities and Japanese agency securities, of which the fair values were ¥69,805 million and ¥4,307 million, respectively, at March 31, 2016, and ¥54,473 million and ¥34,743 million, respectively, at September 30, 2016. U.S. agency securities primarily consist of Ginnie Mae securities, which are guaranteed by the United States government. All Japanese agency securities are mortgage-backed securities issued by Japan Housing Finance Agency, a Japanese government-sponsored enterprise.

Investments (Realized Gains (Lo

Investments (Realized Gains (Losses) on Sales of Available-for-Sale Securities) (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Schedule of Available-for-sale Securities [Line Items]
Gross realized gains	¥ 144,796	¥ 128,495
Gross realized losses	(9,615)	(14,949)
Net realized gains (losses) on sales of available-for-salesecurities	¥ 135,181	¥ 113,546

Investments (Composition of Oth

Investments (Composition of Other Investments) (Detail) - JPY (¥) ¥ in Millions	Sep. 30, 2016	Mar. 31, 2016
Schedule of Cost-method Investments [Line Items]
Equity method investments	¥ 242,744	¥ 258,180
Investments held by consolidated investment companies	37,481	42,045
Other equity interests	300,629	313,221
Total	¥ 580,854	¥ 613,446

Loans (Loans Outstanding by Dom

Loans (Loans Outstanding by Domicile and Industry of Borrower) (Detail) - JPY (¥) ¥ in Millions		Sep. 30, 2016	Mar. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[1]	¥ 76,532,216	¥ 77,722,525
Less: Unearned income and deferred loan fees-net		150,308	167,156
Loans outstanding		76,381,908	77,555,369
Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		53,600,842	52,572,432
Domestic | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		8,086,048	8,344,808
Domestic | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		7,666,062	7,733,513
Domestic | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		4,560,155	4,655,704
Domestic | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		5,100,718	5,408,850
Domestic | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		3,528,283	3,267,902
Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		3,579,276	3,632,481
Domestic | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		5,682,739	3,395,784
Domestic | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[2]	4,244,129	4,619,336
Domestic | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		10,241,326	10,589,646
Domestic | Other individual loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		912,106	924,408
Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		22,931,374	25,150,093
Foreign | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		6,022,059	6,382,449
Foreign | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		921,697	1,174,665
Foreign | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		15,784,820	17,319,284
Foreign | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[2]	¥ 202,798	¥ 273,695
[1]	Amounts represent loan balances before deducting unearned income and deferred loan fees.
[2]	Other industries of Domestic and Other of Foreign include trade receivables and lease receivables of consolidated VIEs.

Loans (Credit Quality Indicator

Loans (Credit Quality Indicators of Financing Receivables) (Detail) - JPY (¥) ¥ in Millions		Sep. 30, 2016	Mar. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[1]	¥ 76,532,216	¥ 77,722,525
Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		53,600,842	52,572,432
Domestic | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		8,086,048	8,344,808
Domestic | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		7,666,062	7,733,513
Domestic | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		4,560,155	4,655,704
Domestic | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		5,100,718	5,408,850
Domestic | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		3,528,283	3,267,902
Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		3,579,276	3,632,481
Domestic | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		5,682,739	3,395,784
Domestic | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[2]	4,244,129	4,619,336
Domestic | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		11,153,432	11,514,054
Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		22,931,374	25,150,093
Foreign | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		6,022,059	6,382,449
Foreign | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		921,697	1,174,665
Financing Receivables Not Impaired | Normal obligors | A-B
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		40,134,297	39,473,402
Financing Receivables Not Impaired | Normal obligors | C-D
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		16,642,532	17,892,639
Financing Receivables Not Impaired | Normal obligors | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3]	11,727,702	12,115,160
Financing Receivables Not Impaired | Normal obligors | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	5,654,041	5,749,767
Financing Receivables Not Impaired | Normal obligors | Domestic | A-B
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		25,659,786	23,933,055
Financing Receivables Not Impaired | Normal obligors | Domestic | A-B | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		4,821,589	4,859,256
Financing Receivables Not Impaired | Normal obligors | Domestic | A-B | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		4,038,679	3,956,798
Financing Receivables Not Impaired | Normal obligors | Domestic | A-B | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		2,591,663	2,611,296
Financing Receivables Not Impaired | Normal obligors | Domestic | A-B | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		2,158,490	2,240,228
Financing Receivables Not Impaired | Normal obligors | Domestic | A-B | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		2,682,877	2,410,967
Financing Receivables Not Impaired | Normal obligors | Domestic | A-B | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		2,698,093	2,719,047
Financing Receivables Not Impaired | Normal obligors | Domestic | A-B | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		4,802,983	3,181,241
Financing Receivables Not Impaired | Normal obligors | Domestic | A-B | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		1,865,412	1,954,222
Financing Receivables Not Impaired | Normal obligors | Domestic | C-D
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		11,541,048	12,144,508
Financing Receivables Not Impaired | Normal obligors | Domestic | C-D | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		2,511,839	2,681,958
Financing Receivables Not Impaired | Normal obligors | Domestic | C-D | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		2,662,926	2,709,617
Financing Receivables Not Impaired | Normal obligors | Domestic | C-D | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		1,617,784	1,674,328
Financing Receivables Not Impaired | Normal obligors | Domestic | C-D | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		2,368,145	2,552,552
Financing Receivables Not Impaired | Normal obligors | Domestic | C-D | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		688,034	695,697
Financing Receivables Not Impaired | Normal obligors | Domestic | C-D | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		842,036	881,405
Financing Receivables Not Impaired | Normal obligors | Domestic | C-D | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		3,750	4,047
Financing Receivables Not Impaired | Normal obligors | Domestic | C-D | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		574,973	685,258
Financing Receivables Not Impaired | Normal obligors | Domestic | C-D | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		271,561	259,646
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3]	11,718,586	12,106,778
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3]	94,614	103,343
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3]	580,874	601,251
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3]	186,542	195,140
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3]	205,881	223,677
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3]	84,095	86,094
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3]	1,812	2,234
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3]	3,253	3,501
Financing Receivables Not Impaired | Normal obligors | Domestic | Retail | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3]	10,561,515	10,891,538
Financing Receivables Not Impaired | Normal obligors | Domestic | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	2,958,990	2,616,911
Financing Receivables Not Impaired | Normal obligors | Domestic | Other | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	114,648	148,102
Financing Receivables Not Impaired | Normal obligors | Domestic | Other | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	101,261	157,057
Financing Receivables Not Impaired | Normal obligors | Domestic | Other | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	1,495	2,380
Financing Receivables Not Impaired | Normal obligors | Domestic | Other | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	32,117	57,865
Financing Receivables Not Impaired | Normal obligors | Domestic | Other | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	205	380
Financing Receivables Not Impaired | Normal obligors | Domestic | Other | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	554	3,788
Financing Receivables Not Impaired | Normal obligors | Domestic | Other | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	876,006	210,496
Financing Receivables Not Impaired | Normal obligors | Domestic | Other | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	1,753,107	1,929,712
Financing Receivables Not Impaired | Normal obligors | Domestic | Other | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	79,597	107,131
Financing Receivables Not Impaired | Normal obligors | Foreign | A-B
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		14,474,511	15,540,347
Financing Receivables Not Impaired | Normal obligors | Foreign | C-D
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		5,101,484	5,748,131
Financing Receivables Not Impaired | Normal obligors | Foreign | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3]	9,116	8,382
Financing Receivables Not Impaired | Normal obligors | Foreign | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4]	2,695,051	3,132,856
Financing Receivables Not Impaired | Watch obligors | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3],[5]	194,450	201,063
Financing Receivables Not Impaired | Watch obligors | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[5]	112,591	121,340
Financing Receivables Not Impaired | Watch obligors | E1 to E2 Rating
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	1,108,303	1,179,451
Financing Receivables Not Impaired | Watch obligors | Domestic | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3],[5]	194,441	201,053
Financing Receivables Not Impaired | Watch obligors | Domestic | Retail | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3],[5]	12,020	12,473
Financing Receivables Not Impaired | Watch obligors | Domestic | Retail | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3],[5]	16,775	16,408
Financing Receivables Not Impaired | Watch obligors | Domestic | Retail | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3],[5]	25,071	24,846
Financing Receivables Not Impaired | Watch obligors | Domestic | Retail | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3],[5]	37,476	39,486
Financing Receivables Not Impaired | Watch obligors | Domestic | Retail | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3],[5]	9,691	10,518
Financing Receivables Not Impaired | Watch obligors | Domestic | Retail | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3],[5]	385	264
Financing Receivables Not Impaired | Watch obligors | Domestic | Retail | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3],[5]	402	329
Financing Receivables Not Impaired | Watch obligors | Domestic | Retail | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3],[5]	92,621	96,729
Financing Receivables Not Impaired | Watch obligors | Domestic | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[5]	40,121	40,733
Financing Receivables Not Impaired | Watch obligors | Domestic | Other | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[5]	3,768	2,958
Financing Receivables Not Impaired | Watch obligors | Domestic | Other | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[5]	384	255
Financing Receivables Not Impaired | Watch obligors | Domestic | Other | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[5]	51
Financing Receivables Not Impaired | Watch obligors | Domestic | Other | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[5]	281	546
Financing Receivables Not Impaired | Watch obligors | Domestic | Other | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[5]	34,224	35,315
Financing Receivables Not Impaired | Watch obligors | Domestic | Other | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[5]	1,413	1,659
Financing Receivables Not Impaired | Watch obligors | Domestic | E1 to E2 Rating
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	679,471	706,755
Financing Receivables Not Impaired | Watch obligors | Domestic | E1 to E2 Rating | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	152,447	163,213
Financing Receivables Not Impaired | Watch obligors | Domestic | E1 to E2 Rating | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	199,136	215,244
Financing Receivables Not Impaired | Watch obligors | Domestic | E1 to E2 Rating | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	71,778	81,704
Financing Receivables Not Impaired | Watch obligors | Domestic | E1 to E2 Rating | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	145,727	147,404
Financing Receivables Not Impaired | Watch obligors | Domestic | E1 to E2 Rating | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	43,046	35,090
Financing Receivables Not Impaired | Watch obligors | Domestic | E1 to E2 Rating | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	30,461	22,303
Financing Receivables Not Impaired | Watch obligors | Domestic | E1 to E2 Rating | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	5,154	7,053
Financing Receivables Not Impaired | Watch obligors | Domestic | E1 to E2 Rating | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	31,722	34,744
Financing Receivables Not Impaired | Watch obligors | Foreign | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[3],[5]	9	10
Financing Receivables Not Impaired | Watch obligors | Foreign | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[4],[5]	72,470	80,607
Financing Receivables Not Impaired | Watch obligors | Foreign | E1 to E2 Rating
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding	[5]	428,832	472,696
Financing Receivables Impaired | Impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		958,300	989,703
Financing Receivables Impaired | Impaired loans | Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		808,399	822,639
Financing Receivables Impaired | Impaired loans | Domestic | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		375,123	373,505
Financing Receivables Impaired | Impaired loans | Domestic | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		66,027	76,883
Financing Receivables Impaired | Impaired loans | Domestic | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		65,771	66,010
Financing Receivables Impaired | Impaired loans | Domestic | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		152,601	147,092
Financing Receivables Impaired | Impaired loans | Domestic | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		20,335	29,156
Financing Receivables Impaired | Impaired loans | Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		5,935	3,440
Financing Receivables Impaired | Impaired loans | Domestic | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		7,604	3,946
Financing Receivables Impaired | Impaired loans | Domestic | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		115,003	122,607
Financing Receivables Impaired | Impaired loans | Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans outstanding		¥ 149,901	¥ 167,064
[1]	Amounts represent loan balances before deducting unearned income and deferred loan fees.
[2]	Other industries of Domestic and Other of Foreign include trade receivables and lease receivables of consolidated VIEs.
[3]	Amounts represent small balance, homogeneous loans which are subject to pool allocations.
[4]	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.
[5]	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 - Additional Information

Loans - Additional Information (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2016	Mar. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale	¥ 35,024	¥ 33,133
Impaired Financing Receivables with No Related Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans partially charged off	¥ 28,803	¥ 31,933
Minimum | Impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of days past due	90 days

Loans (Impaired Loans) (Detail)

Loans (Impaired Loans) (Detail) - JPY (¥) ¥ in Millions		6 Months Ended	12 Months Ended
		Sep. 30, 2016	Mar. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	¥ 836,999	¥ 860,848
Recorded investment not requiring an allowance for loan losses	[1],[2]	121,301	128,855
Total	[1]	958,300	989,703
Unpaid principal balance		1,017,110	1,051,240
Related allowance	[3]	293,012	289,186
Average recorded investment		974,001	1,078,842
Interest income recognized	[4]	5,945	18,267
Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	702,604	712,377
Recorded investment not requiring an allowance for loan losses	[1],[2]	105,795	110,262
Total	[1]	808,399	822,639
Unpaid principal balance		853,269	870,370
Related allowance	[3]	233,579	227,878
Average recorded investment		815,519	892,402
Interest income recognized	[4]	5,057	15,638
Domestic | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	367,787	365,361
Recorded investment not requiring an allowance for loan losses	[1],[2]	7,336	8,144
Total	[1]	375,123	373,505
Unpaid principal balance		381,412	379,642
Related allowance	[3]	141,908	138,676
Average recorded investment		374,314	410,491
Interest income recognized	[4]	1,404	7,930
Domestic | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	51,468	59,883
Recorded investment not requiring an allowance for loan losses	[1],[2]	14,559	17,000
Total	[1]	66,027	76,883
Unpaid principal balance		75,170	87,516
Related allowance	[3]	7,712	10,130
Average recorded investment		71,455	89,075
Interest income recognized	[4]	572	1,246
Domestic | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	58,030	56,695
Recorded investment not requiring an allowance for loan losses	[1],[2]	7,741	9,315
Total	[1]	65,771	66,010
Unpaid principal balance		72,960	72,603
Related allowance	[3]	19,725	19,095
Average recorded investment		65,890	69,525
Interest income recognized	[4]	604	1,292
Domestic | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	141,135	134,425
Recorded investment not requiring an allowance for loan losses	[1],[2]	11,466	12,667
Total	[1]	152,601	147,092
Unpaid principal balance		161,702	157,215
Related allowance	[3]	50,449	46,304
Average recorded investment		149,847	149,324
Interest income recognized	[4]	1,222	2,376
Domestic | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	16,508	25,665
Recorded investment not requiring an allowance for loan losses	[1],[2]	3,827	3,491
Total	[1]	20,335	29,156
Unpaid principal balance		21,376	30,497
Related allowance	[3]	4,567	5,694
Average recorded investment		24,746	33,119
Interest income recognized	[4]	215	630
Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	3,072	3,390
Recorded investment not requiring an allowance for loan losses	[1],[2]	2,863	50
Total	[1]	5,935	3,440
Unpaid principal balance		5,935	3,440
Related allowance	[3]	1,055	1,095
Average recorded investment		4,687	5,188
Interest income recognized	[4]	30	42
Domestic | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	7,543	3,591
Recorded investment not requiring an allowance for loan losses	[1],[2]	61	355
Total	[1]	7,604	3,946
Unpaid principal balance		7,790	4,132
Related allowance	[3]	2,277	799
Average recorded investment		5,775	2,665
Interest income recognized	[4]	43	64
Domestic | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	57,061	63,367
Recorded investment not requiring an allowance for loan losses	[1],[2]	57,942	59,240
Total	[1]	115,003	122,607
Unpaid principal balance		126,924	135,325
Related allowance	[3]	5,886	6,085
Average recorded investment		118,805	133,015
Interest income recognized	[4]	967	2,058
Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment requiring an allowance for loan losses	[1]	134,395	148,471
Recorded investment not requiring an allowance for loan losses	[1],[2]	15,506	18,593
Total	[1]	149,901	167,064
Unpaid principal balance		163,841	180,870
Related allowance	[3]	59,433	61,308
Average recorded investment		158,482	186,440
Interest income recognized	[4]	¥ 888	¥ 2,629
[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 small balance, homogeneous loans totaling ¥347,839 million and ¥330,764 million as of March 31, 2016 and September 30, 2016 which were collectively evaluated for impairment, in addition to the allowance for those that were individually evaluated for impairment.
[4]	Amounts represent gross interest income on impaired loans which were included in Interest income on loans in the consolidated statements of income.

Loans (Impaired Loans) (Parenth

Loans (Impaired Loans) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions		Sep. 30, 2016	Mar. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment	[1]	¥ 958,300	¥ 989,703
Small balance homogeneous loans of which were collectively evaluated for impairment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment		¥ 330,764	¥ 347,839
[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.

Loans (Troubled Debt Restructur

Loans (Troubled Debt Restructuring) (Detail) - JPY (¥) ¥ in Millions		6 Months Ended
		Sep. 30, 2016	Sep. 30, 2015
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	[1]		¥ 67,107
Loan forgiveness or debt to equity swaps charge-off			34,360
Interest rate reduction and/or postponement of principal and/or interest		¥ 206,442	237,342
Domestic
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	[1]		67,107
Loan forgiveness or debt to equity swaps charge-off			34,360
Interest rate reduction and/or postponement of principal and/or interest		195,593	213,371
Domestic | Manufacturing
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	[1]		67,058
Loan forgiveness or debt to equity swaps charge-off			34,081
Interest rate reduction and/or postponement of principal and/or interest		54,476	60,865
Domestic | Construction and real estate
Financing Receivable, Modifications [Line Items]
Interest rate reduction and/or postponement of principal and/or interest		8,596	15,059
Domestic | Services
Financing Receivable, Modifications [Line Items]
Interest rate reduction and/or postponement of principal and/or interest		21,951	23,345
Domestic | Wholesale and retail
Financing Receivable, Modifications [Line Items]
Interest rate reduction and/or postponement of principal and/or interest		87,237	77,097
Domestic | Transportation and communications
Financing Receivable, Modifications [Line Items]
Loan forgiveness or debt to equity swaps Recorded investment	[1]		49
Loan forgiveness or debt to equity swaps charge-off			279
Interest rate reduction and/or postponement of principal and/or interest		8,656	12,230
Domestic | Banks and other financial institutions
Financing Receivable, Modifications [Line Items]
Interest rate reduction and/or postponement of principal and/or interest		3,198	4,776
Domestic | Other industries
Financing Receivable, Modifications [Line Items]
Interest rate reduction and/or postponement of principal and/or interest		2,274	2,933
Domestic | Individuals
Financing Receivable, Modifications [Line Items]
Interest rate reduction and/or postponement of principal and/or interest		9,205	17,066
Foreign
Financing Receivable, Modifications [Line Items]
Interest rate reduction and/or postponement of principal and/or interest		¥ 10,849	¥ 23,971
[1]	Amounts represent the book values of loans immediately after the restructurings.

Loans (Loans Modified as Troubl

Loans (Loans Modified as Troubled Debt Restructuring within Previous Twelve Months and for which There Was Payment Default During Current Fiscal Year) (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Financing Receivable, Modifications [Line Items]
Recorded investment	¥ 11,391	¥ 30,230
Domestic
Financing Receivable, Modifications [Line Items]
Recorded investment	11,361	23,329
Domestic | Manufacturing
Financing Receivable, Modifications [Line Items]
Recorded investment	1,801	2,890
Domestic | Construction and real estate
Financing Receivable, Modifications [Line Items]
Recorded investment	1,621	1,731
Domestic | Services
Financing Receivable, Modifications [Line Items]
Recorded investment	1,188	2,710
Domestic | Wholesale and retail
Financing Receivable, Modifications [Line Items]
Recorded investment	4,614	13,097
Domestic | Transportation and communications
Financing Receivable, Modifications [Line Items]
Recorded investment	771	833
Domestic | Individuals
Financing Receivable, Modifications [Line Items]
Recorded investment	1,366	2,068
Foreign
Financing Receivable, Modifications [Line Items]
Recorded investment	¥ 30	¥ 6,901

Loans (Age Analysis of Past Due

Loans (Age Analysis of Past Due Loans) (Detail) - JPY (¥) ¥ in Millions		Sep. 30, 2016	Mar. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		¥ 241,006	¥ 200,117
Current		76,291,210	77,522,408
Total	[1]	76,532,216	77,722,525
30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		80,961	50,075
60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		14,422	18,545
90 Days or More Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		145,623	131,497
Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		160,330	166,660
Current		53,440,512	52,405,772
Total		53,600,842	52,572,432
Domestic | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		12,568	11,172
Current		8,073,480	8,333,636
Total		8,086,048	8,344,808
Domestic | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		39,475	39,428
Current		7,626,587	7,694,085
Total		7,666,062	7,733,513
Domestic | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		9,648	9,718
Current		4,550,507	4,645,986
Total		4,560,155	4,655,704
Domestic | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		9,156	12,940
Current		5,091,562	5,395,910
Total		5,100,718	5,408,850
Domestic | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		2,318	2,708
Current		3,525,965	3,265,194
Total		3,528,283	3,267,902
Domestic | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		16
Current		3,579,260	3,632,481
Total		3,579,276	3,632,481
Domestic | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current		5,682,739	3,395,784
Total		5,682,739	3,395,784
Domestic | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		83	29
Current		4,244,046	4,619,307
Total	[2]	4,244,129	4,619,336
Domestic | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		87,066	90,665
Current		11,066,366	11,423,389
Total		11,153,432	11,514,054
Domestic | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		45,044	49,216
Domestic | 30-59 Days Past Due | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		1,467	1,555
Domestic | 30-59 Days Past Due | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		2,449	2,713
Domestic | 30-59 Days Past Due | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		1,030	2,479
Domestic | 30-59 Days Past Due | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		1,561	3,193
Domestic | 30-59 Days Past Due | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		279	594
Domestic | 30-59 Days Past Due | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		16
Domestic | 30-59 Days Past Due | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		41
Domestic | 30-59 Days Past Due | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		38,201	38,682
Domestic | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		13,171	15,947
Domestic | 60-89 Days Past Due | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		41	163
Domestic | 60-89 Days Past Due | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		1,488	1,024
Domestic | 60-89 Days Past Due | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		572	223
Domestic | 60-89 Days Past Due | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		681	886
Domestic | 60-89 Days Past Due | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due			81
Domestic | 60-89 Days Past Due | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		14
Domestic | 60-89 Days Past Due | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		10,375	13,570
Domestic | 90 Days or More Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		102,115	101,497
Domestic | 90 Days or More Past Due | Manufacturing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		11,060	9,454
Domestic | 90 Days or More Past Due | Construction and real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		35,538	35,691
Domestic | 90 Days or More Past Due | Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		8,046	7,016
Domestic | 90 Days or More Past Due | Wholesale and retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		6,914	8,861
Domestic | 90 Days or More Past Due | Transportation and communications
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		2,039	2,033
Domestic | 90 Days or More Past Due | Other industries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		28	29
Domestic | 90 Days or More Past Due | Individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		38,490	38,413
Foreign
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		80,676	33,457
Current		22,850,698	25,116,636
Total		22,931,374	25,150,093
Foreign | Banks and other financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		6,022,059	6,382,449
Foreign | Government and public institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total		921,697	1,174,665
Foreign | 30-59 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		35,917	859
Foreign | 60-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		1,251	2,598
Foreign | 90 Days or More Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due		¥ 43,508	¥ 30,000
[1]	Amounts represent loan balances before deducting unearned income and deferred loan fees.
[2]	Other industries of Domestic and Other of Foreign include trade receivables and lease receivables of consolidated VIEs.

Allowance For Loan Losses - Add

Allowance For Loan Losses - Additional Information (Detail)	6 Months Ended
	Sep. 30, 2016
Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Period in which obligors generally determined to be substantially bankrupt, past due (in months)	6 months

Allowance For Loan Losses (Chan

Allowance For Loan Losses (Changes in Allowance for Loan Losses) (Detail) - JPY (¥) ¥ in Millions		6 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Mar. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period		¥ 451,247	¥ 520,259
Provision (credit) for loan losses		569	3,030
Charge-offs		(15,160)	(67,219)
Recoveries		15,741	9,742
Net charge-offs		581	(57,477)
Others	[1]	(15,217)	(774)
Balance at end of fiscal year		437,180	465,038
Allowance for loan losses of which individually evaluated for impairment		241,053		¥ 238,941
Allowance for loan losses of which collectively evaluated for impairment		196,127		212,306
Loans	[2]	76,532,216		77,722,525
Loans of which individually evaluated for impairment	[2]	684,784		722,097
Loans of which collectively evaluated for impairment	[2]	75,847,432		77,000,428
Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period		367,739	423,177
Provision (credit) for loan losses		9,123	6,878
Charge-offs		(10,332)	(59,795)
Recoveries		8,877	7,733
Net charge-offs		(1,455)	(52,062)
Others	[1]	(10,404)	(971)
Balance at end of fiscal year		365,003	377,022
Allowance for loan losses of which individually evaluated for impairment		226,809		222,591
Allowance for loan losses of which collectively evaluated for impairment		138,194		145,148
Loans	[2]	58,704,366		59,385,962
Loans of which individually evaluated for impairment	[2]	598,269		634,049
Loans of which collectively evaluated for impairment	[2]	58,106,097		58,751,913
Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period		44,221	60,469
Provision (credit) for loan losses		(7,983)	(10,052)
Charge-offs		(1,016)	(1,251)
Recoveries		4,725	634
Net charge-offs		3,709	(617)
Balance at end of fiscal year		39,947	49,800
Allowance for loan losses of which individually evaluated for impairment		3,441		3,829
Allowance for loan losses of which collectively evaluated for impairment		36,506		40,392
Loans	[2]	12,017,580		12,414,453
Loans of which individually evaluated for impairment	[2]	24,472		24,768
Loans of which collectively evaluated for impairment	[2]	11,993,108		12,389,685
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period		39,287	36,613
Provision (credit) for loan losses		(571)	6,204
Charge-offs		(3,812)	(6,173)
Recoveries		2,139	1,375
Net charge-offs		(1,673)	(4,798)
Others	[1]	(4,813)	197
Balance at end of fiscal year		32,230	¥ 38,216
Allowance for loan losses of which individually evaluated for impairment		10,803		12,521
Allowance for loan losses of which collectively evaluated for impairment		21,427		26,766
Loans	[2]	5,810,270		5,922,110
Loans of which individually evaluated for impairment	[2]	62,043		63,280
Loans of which collectively evaluated for impairment	[2]	¥ 5,748,227		¥ 5,858,830
[1]	Others includes primarily foreign exchange translation.
[2]	Amounts represent loan balances before deducting unearned income and deferred loan fees.

Other Assets and Liabilities (S

Other Assets and Liabilities (Schedule of Other Assets and Other Liabilities) (Detail) - JPY (¥) ¥ in Millions	Sep. 30, 2016	Mar. 31, 2016
Other assets:
Accounts receivable from brokers, dealers and customers for securities transactions	¥ 1,772,693	¥ 1,718,769
Collateral provided for derivative transactions	1,021,305	884,651
Prepaid pension cost	638,596	612,102
Miscellaneous receivables	266,944	286,896
Margins provided for futures contracts	190,893	225,240
Security deposits	112,218	113,066
Loans held for sale	35,024	33,133
Other	837,087	823,033
Total	4,874,760	4,696,890
Other liabilities:
Accounts payable to brokers, dealers and customers for securities transactions	2,907,787	2,882,824
Collateral accepted for derivative transactions	979,152	715,894
Guaranteed trust principal	651,254	623,904
Miscellaneous payables	408,148	442,352
Margins accepted for futures contracts	328,362	334,925
Factoring amounts owed to customers	164,629	242,392
Unearned income	134,618	144,903
Other	1,067,604	1,089,529
Total	¥ 6,641,554	¥ 6,476,723

Preferred and Common Stock (Com

Preferred and Common Stock (Composition of Preferred Stock) (Detail) - JPY (¥) ¥ in Millions		Sep. 30, 2016	Mar. 31, 2016
Class of Stock [Line Items]
Aggregate amount			¥ 914,752
Number of shares Authorized		4,214,752,000	4,214,752,000
Number of shares Issued			914,752,000
Number of shares In treasury		21,895,432	10,929,211
Preferred stock
Class of Stock [Line Items]
Number of shares In treasury			815,828,400
Eleventh series class XI preferred stock
Class of Stock [Line Items]
Aggregate amount	[1]		¥ 914,752
Number of shares Authorized	[1]		914,752,000
Number of shares Issued	[1]		914,752,000
Eleventh series class XI preferred stock | Preferred stock
Class of Stock [Line Items]
Number of shares In treasury	[1]		815,828,400
First series class XIV preferred stock
Class of Stock [Line Items]
Number of shares Authorized	[2]	900,000,000	900,000,000
Second series class XIV preferred stock
Class of Stock [Line Items]
Number of shares Authorized	[2]	900,000,000	900,000,000
Third series class XIV preferred stock
Class of Stock [Line Items]
Number of shares Authorized	[2]	900,000,000	900,000,000
Fourth series class XIV preferred stock
Class of Stock [Line Items]
Number of shares Authorized	[2]	900,000,000	900,000,000
First series class XV preferred stock
Class of Stock [Line Items]
Number of shares Authorized	[3]	900,000,000	900,000,000
Second series class XV preferred stock
Class of Stock [Line Items]
Number of shares Authorized	[3]	900,000,000	900,000,000
Third series class XV preferred stock
Class of Stock [Line Items]
Number of shares Authorized	[3]	900,000,000	900,000,000
Fourth series class XV preferred stock
Class of Stock [Line Items]
Number of shares Authorized	[3]	900,000,000	900,000,000
First series class XVI preferred stock
Class of Stock [Line Items]
Number of shares Authorized	[4]	1,500,000,000	1,500,000,000
Second series class XVI preferred stock
Class of Stock [Line Items]
Number of shares Authorized	[4]	1,500,000,000	1,500,000,000
Third series class XVI preferred stock
Class of Stock [Line Items]
Number of shares Authorized	[4]	1,500,000,000	1,500,000,000
Fourth series class XVI preferred stock
Class of Stock [Line Items]
Number of shares Authorized	[4]	1,500,000,000	1,500,000,000
Class XI preferred stock
Class of Stock [Line Items]
Number of shares Authorized		914,752,000
[1]	The aggregate amount and number of issued shares include the preferred stock in treasury which has been converted into common stock but not yet cancelled.
[2]	The total number of authorized shares from first to fourth series class XIV preferred stock shall not exceed 900,000,000.
[3]	The total number of authorized shares from first to fourth series class XV preferred stock shall not exceed 900,000,000.
[4]	The total number of authorized shares from first to fourth series class XVI preferred stock shall not exceed 1,500,000,000.

Preferred and Common Stock (C71

Preferred and Common Stock (Composition of Preferred Stock) (Parenthetical) (Detail) - shares	Sep. 30, 2016	Mar. 31, 2016
Class of Stock [Line Items]
Number of shares Authorized	4,214,752,000	4,214,752,000
First to fourth series class XIV Preferred Stock | Maximum
Class of Stock [Line Items]
Number of shares Authorized	900,000,000
First to fourth series class XV Preferred Stock | Maximum
Class of Stock [Line Items]
Number of shares Authorized	900,000,000
First to fourth series class XVI Preferred Stock | Maximum
Class of Stock [Line Items]
Number of shares Authorized	1,500,000,000

Preferred and Common Stock - Ad

Preferred and Common Stock - Additional Information (Detail) - shares	6 Months Ended
	Sep. 30, 2016	Mar. 31, 2016
Class of Stock [Line Items]
Common stock, issued	25,386,307,945	25,030,525,657
Increase in common stock shares	355,782,288

Dividends (Dividends on Preferr

Dividends (Dividends on Preferred Stock and Common Stock) (Detail) - JPY (¥) ¥ / shares in Units, ¥ in Millions	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Japan Gaap Dividends Payable [Line Items]
Cash dividends In aggregate	¥ 94,828	¥ 100,584
Eleventh series class XI preferred stock
Japan Gaap Dividends Payable [Line Items]
Cash dividends Per share	¥ 10	¥ 10
Cash dividends In aggregate	¥ 989	¥ 2,131
Common stock
Japan Gaap Dividends Payable [Line Items]
Cash dividends Per share	¥ 3.75	¥ 4
Cash dividends In aggregate	¥ 93,839	¥ 98,453

Accumulated Other Comprehensi74

Accumulated Other Comprehensive Income (Changes in Each Component of Accumulated Other Comprehensive Income (Loss), Net Of Tax (AOCI) (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	¥ 8,183,191
Less: reclassification adjustments for losses (gains) included in net income	(86,612)
Change during period	(196,229)	¥ (297,397)
Balance at end of period	8,264,977	8,138,447
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	1,469,638	2,041,005
Change during period	(195,339)	(296,070)
Balance at end of period	1,274,299	1,744,935
Accumulated Net Unrealized Investment Gain (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	1,409,374	1,747,607
Before reclassification adjustments during year	(49,362)	(179,849)
Less: reclassification adjustments for losses (gains) included in net income	(86,761)	(72,860)
Change during period	(136,123)	(252,709)
Balance at end of period	1,273,251	1,494,898
Accumulated Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	6,725	129,179
Before reclassification adjustments during year	(59,893)	(43,121)
Change during period	(59,893)	(43,121)
Balance at end of period	(53,168)	86,058
Accumulated Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	53,539	164,219
Before reclassification adjustments during year	533	1,314
Less: reclassification adjustments for losses (gains) included in net income	144	(1,554)
Change during period	677	(240)
Balance at end of period	54,216	163,979
Previously Reported | Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	1,469,308	2,041,005
Previously Reported | Accumulated Net Unrealized Investment Gain (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	1,409,459	1,747,607
Previously Reported | Accumulated Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	6,310	¥ 129,179
Restatement Adjustment | Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	330
Restatement Adjustment | Accumulated Net Unrealized Investment Gain (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(85)
Restatement Adjustment | Accumulated Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	¥ 415

Accumulated Other Comprehensi75

Accumulated Other Comprehensive Income (Amounts Reclassified Out of Accumulated Other Comprehensive Income into Net Income) (Detail) - JPY (¥) ¥ in Millions		6 Months Ended
		Sep. 30, 2016	Sep. 30, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Before tax	[1]	¥ 124,876
Tax effect	[2]	(38,264)
Net of tax before allocation to noncontrolling interests		86,612
Net of tax attributable to noncontrolling interests	[2]	5
Net of tax attributable to MHFG shareholders		86,617
Accumulated Net Unrealized Investment Gain (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net of tax before allocation to noncontrolling interests		86,761	¥ 72,860
Accumulated Net Unrealized Investment Gain (Loss) | Investment gains (losses)-net
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Before tax	[1]	125,109
Tax effect	[2]	(38,351)
Net of tax before allocation to noncontrolling interests		86,758
Net of tax attributable to noncontrolling interests	[2]	3
Net of tax attributable to MHFG shareholders		86,761
Accumulated Defined Benefit Plans Adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net of tax before allocation to noncontrolling interests		(144)	¥ 1,554
Accumulated Defined Benefit Plans Adjustment | Salaries and employee benefits
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Before tax	[1]	(233)
Tax effect	[2]	87
Net of tax before allocation to noncontrolling interests		(146)
Net of tax attributable to noncontrolling interests	[2]	2
Net of tax attributable to MHFG shareholders		¥ (144)
[1]	The amounts in the Before tax column are recorded in each account presented under the heading "Affected line items in the consolidated statements of income".
[2]	The amounts in the Tax effect column and Net of tax attributable to noncontrolling interests column are recorded in Income tax expense and Net income attributable to noncontrolling interests in the consolidated statements of income, respectively.

Regulatory Matters (Capital Ade

Regulatory Matters (Capital Adequacy Ratios of MHFG MHBK and MHTB) (Detail) - JPY (¥) ¥ in Billions		Sep. 30, 2016	Mar. 31, 2016
Mizuho Financial Group Inc | Consolidated
Common Equity Tier 1 capital:
Required	[1]	¥ 3,314	¥ 3,361
Actual		6,769	6,566
Tier 1 capital:
Required	[1]	4,238	4,299
Actual		7,983	7,905
Total risk-based capital:
Required	[1]	5,471	5,550
Actual		¥ 9,768	¥ 9,639
Common Equity Tier 1 capital:
Required	[1]	5.375%	5.375%
Actual		10.98%	10.50%
Tier 1 capital:
Required	[1]	6.875%	6.875%
Actual		12.94%	12.64%
Total risk-based capital:
Required	[1]	8.875%	8.875%
Actual		15.84%	15.41%
Mizuho Bank Limited | Consolidated
Common Equity Tier 1 capital:
Required		¥ 2,532	¥ 2,555
Actual		6,202	6,142
Tier 1 capital:
Required		3,376	3,406
Actual		7,440	7,244
Total risk-based capital:
Required		4,501	4,542
Actual		¥ 9,012	¥ 8,780
Common Equity Tier 1 capital:
Required		4.50%	4.50%
Actual		11.02%	10.81%
Tier 1 capital:
Required		6.00%	6.00%
Actual		13.22%	12.75%
Total risk-based capital:
Required		8.00%	8.00%
Actual		16.01%	15.46%
Mizuho Bank Limited | Non-consolidated
Common Equity Tier 1 capital:
Required		¥ 2,431	¥ 2,489
Actual		5,977	5,892
Tier 1 capital:
Required		3,242	3,318
Actual		7,239	7,004
Total risk-based capital:
Required		4,323	4,424
Actual		¥ 8,846	¥ 8,576
Common Equity Tier 1 capital:
Required		4.50%	4.50%
Actual		11.06%	10.65%
Tier 1 capital:
Required		6.00%	6.00%
Actual		13.39%	12.66%
Total risk-based capital:
Required		8.00%	8.00%
Actual		16.37%	15.50%
Mizuho Trust & Banking Company Limited | Consolidated
Common Equity Tier 1 capital:
Required		¥ 108	¥ 109
Actual		452	440
Tier 1 capital:
Required		144	145
Actual		452	440
Total risk-based capital:
Required		192	193
Actual		¥ 479	¥ 472
Common Equity Tier 1 capital:
Required		4.50%	4.50%
Actual		18.80%	18.21%
Tier 1 capital:
Required		6.00%	6.00%
Actual		18.80%	18.21%
Total risk-based capital:
Required		8.00%	8.00%
Actual		19.95%	19.52%
Mizuho Trust & Banking Company Limited | Non-consolidated
Common Equity Tier 1 capital:
Required		¥ 109	¥ 109
Actual		462	448
Tier 1 capital:
Required		145	145
Actual		462	448
Total risk-based capital:
Required		194	194
Actual		¥ 489	¥ 480
Common Equity Tier 1 capital:
Required		4.50%	4.50%
Actual		19.05%	18.52%
Tier 1 capital:
Required		6.00%	6.00%
Actual		19.05%	18.52%
Total risk-based capital:
Required		8.00%	8.00%
Actual		20.16%	19.80%
[1]	The required amounts and ratios as of March 31, 2016 and September 30, 2016 include those equivalent to a transition capital conservation buffer of 0.625% and transition additional loss absorbency requirements for a global systemically important bank ("G-SIB") and domestic systemically important bank ("D-SIB") of 0.25% and the sum of the risk weighted assets and each such ratio.

Regulatory Matters (Capital A77

Regulatory Matters (Capital Adequacy Ratios of MHFG MHBK and MHTB) (Parenthetical) (Detail)	6 Months Ended	12 Months Ended
	Sep. 30, 2016	Mar. 31, 2016
Japan Gaap Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Capital conservation buffer	0.625%	0.625%
Additional loss absorbency requirements for G-SIBs and D-SIBs	0.25%	0.25%

Earnings Per Common Share (Comp

Earnings Per Common Share (Computation of Basic and Diluted Earnings Per Common Share) (Detail) - JPY (¥) ¥ / shares in Units, shares in Thousands, ¥ in Millions		6 Months Ended
		Sep. 30, 2016	Sep. 30, 2015
Net income:
Net income attributable to MHFG shareholders		¥ 379,558	¥ 365,873
Less: Net income attributable to preferred shareholders			1,441
Net income attributable to common shareholders		379,558	364,432
Effect of dilutive securities:
Convertible preferred stock			1,441
Net income attributable to common shareholders after assumed conversions		¥ 379,558	¥ 365,873
Shares:
Weighted average common shares outstanding		25,204,801	24,718,566
Effect of dilutive securities:
Convertible preferred stock	[1]	165,533	649,240
Stock options		11,997	18,467
Weighted average common shares after assumed conversions		25,382,331	25,386,273
Amounts per common share:
Basic net income per common share		¥ 15.06	¥ 14.74
Diluted net income per common share		¥ 14.95	¥ 14.41
[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	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Reconciliation of Provision of Income Taxes [Line Items]
Current tax expense	¥ 102,390	¥ 137,371
Deferred tax expense (benefit)	(27,875)	29,890
Total income tax expense	¥ 74,515	¥ 167,261

Income Taxes (Tax Effects of It

Income Taxes (Tax Effects of Items Recorded Directly in Equity) (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Net unrealized gains (losses) on available-for-sale securities:
Unrealized gains (losses)	¥ (21,562)	¥ (86,790)
Less: reclassification adjustments	(38,351)	(34,567)
Total	(59,913)	(121,357)
Foreign currency translation adjustments:
Unrealized gains (losses)	(126)
Less: reclassification adjustments	0	0
Total	(126)
Pension liability adjustments:
Unrealized gains (losses)	239	(118)
Less: reclassification adjustments	87	(692)
Total	326	(810)
Total tax effect before allocation to noncontrolling interests	¥ (59,713)	¥ (122,167)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Income Taxes [Line Items]
Statutory tax rate	30.86%	33.06%
Effective tax rate	16.30%	30.83%
Net operating loss carryforwards	¥ 1,613,000
Unrecognized tax benefits	¥ 1,443

Pension and Other Employee Be82

Pension and Other Employee Benefit Plans (Components of Net Periodic Benefit Cost of Severance Indemnities and Pension Plans of the MHFG Group) (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Service cost-benefits earned during the period	¥ 22,219	¥ 17,803
Interest costs on projected benefit obligations	2,716	6,242
Expected return on plan assets	(17,860)	(20,177)
Amortization of prior service benefits	(97)	(97)
Amortization of net actuarial loss (gain)	385	(2,049)
Special termination benefits	1,744	2,212
Net periodic benefit cost	¥ 9,107	¥ 3,934

Pension and Other Employee Be83

Pension and Other Employee Benefit Plans - Additional Information (Detail) - JPY (¥) ¥ in Billions	6 Months Ended	12 Months Ended
	Sep. 30, 2016	Mar. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Pension plan, contribution expected to be paid during the next fiscal year		¥ 50
Total payment to pension plans	¥ 25
Additional contribution expected to be paid during remainder of fiscal year	¥ 25

Derivative Financial Instrume84

Derivative Financial Instruments (Notional and Fair Value Amounts of Derivative Instruments Outstanding) (Detail) - JPY (¥) ¥ in Billions		Sep. 30, 2016	Mar. 31, 2016
Derivatives, Fair Value [Line Items]
Notional amount	[1]	¥ 1,129,481	¥ 1,216,037
Interest rate contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	986,753	1,066,252
Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	134,265	141,517
Equity-related contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	3,982	3,115
Credit-related contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	4,164	4,826
Other contracts
Derivatives, Fair Value [Line Items]
Notional amount	[1]	317	327
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	22	22
Fair value of derivative payables	[2]		1
Designated as Hedging Instrument | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	6	4
Fair value of derivative payables	[2]		1
Designated as Hedging Instrument | Equity-related contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	16	18
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	17,107	14,902
Fair value of derivative payables	[2]	16,294	14,480
Not Designated as Hedging Instrument | Interest rate contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	13,767	11,522
Fair value of derivative payables	[2]	13,339	11,269
Not Designated as Hedging Instrument | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	3,127	3,126
Fair value of derivative payables	[2]	2,730	2,979
Not Designated as Hedging Instrument | Equity-related contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	137	152
Fair value of derivative payables	[2]	152	140
Not Designated as Hedging Instrument | Credit-related contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	31	43
Fair value of derivative payables	[2]	32	37
Not Designated as Hedging Instrument | Other contracts
Derivatives, Fair Value [Line Items]
Fair value of derivative receivables	[2]	45	59
Fair value of derivative payables	[2]	¥ 41	¥ 55
[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 Instrume85

Derivative Financial Instruments - Additional Information (Detail) - JPY (¥) ¥ in Millions	Sep. 30, 2016	Mar. 31, 2016
Derivative [Line Items]
Cash collateral provided and not offset against derivative positions and included in Other assets	¥ 1,021,305	¥ 884,651
Cash collateral accepted and not offset against derivative positions and included in Other liabilities	¥ 979,152	¥ 715,894

Derivative Financial Instrume86

Derivative Financial Instruments (Gains and Losses Information Related to Fair Value Hedges) (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income- Derivatives	¥ 6,002	¥ 13,450
Gains (losses) recorded in income- Hedged items	(7,807)	(14,798)
Gains (losses) recorded in income- Hedge ineffectiveness	0	0
Gains (losses) recorded in income- Net gain (loss) excluded from assessment of effectiveness	(1,805)	(1,348)
Equity-related contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income- Derivatives	6,002	13,450
Gains (losses) recorded in income- Hedged items	(7,807)	(14,798)
Gains (losses) recorded in income- Hedge ineffectiveness	0	0
Gains (losses) recorded in income- Net gain (loss) excluded from assessment of effectiveness	¥ (1,805)	¥ (1,348)

Derivative Financial Instrume87

Derivative Financial Instruments (Gains and Losses Information Related to Net Investment Hedges) (Detail) - JPY (¥) ¥ in Millions	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Effective portion recorded in OCI	¥ 107,528	¥ 723
Ineffective portion recorded in income	890	200
Financial instruments hedging foreign exchange risk
Derivative Instruments, Gain (Loss) [Line Items]
Effective portion recorded in OCI	107,528	723
Ineffective portion recorded in income	¥ 890	¥ 200

Derivative Financial Instrume88

Derivative Financial Instruments (Gains and Losses Information Related to Net Investment Hedges) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions	Sep. 30, 2016	Sep. 30, 2015
Financial instruments hedging foreign exchange risk
Derivative Instruments, Gain (Loss) [Line Items]
Accumulated other comprehensive income reclassified to earnings	¥ 0	¥ 0

Derivative Financial Instrume89

Derivative Financial Instruments (Gains and Losses on Derivatives Not Designated or Qualifying as Hedges) (Detail) - JPY (¥) ¥ in Millions		6 Months Ended
		Sep. 30, 2016	Sep. 30, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		¥ 97,999	¥ 148,595
Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		80,040	150,748
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		11,173	(4,453)
Equity-related contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income	[1]	11,049	10,268
Credit-related contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income	[2]	(4,827)	(8,419)
Other contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		¥ 564	¥ 451
[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 gain (loss) of ¥3,531 million and ¥(5,698) million on the credit derivatives hedging the credit risk of loans during the six months ended September 30, 2015 and 2016, respectively.

Derivative Financial Instrume90

Derivative Financial Instruments (Gains and Losses on Derivatives Not Designated or Qualifying as Hedges) (Parenthetical) (Detail) - JPY (¥) ¥ in Millions		6 Months Ended
		Sep. 30, 2016	Sep. 30, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		¥ 97,999	¥ 148,595
Credit-related contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income	[1]	(4,827)	(8,419)
Credit-related contracts | Loans related to credit derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in income		¥ (5,698)	¥ 3,531
[1]	Amounts include the net gain (loss) of ¥3,531 million and ¥(5,698) million on the credit derivatives hedging the credit risk of loans during the six months ended September 30, 2015 and 2016, respectively.

Derivative Financial Instrume91

Derivative Financial Instruments (Notional and Fair Value Amounts of Credit Derivatives) (Detail) - JPY (¥) ¥ in Billions	Sep. 30, 2016	Mar. 31, 2016
Credit protection written
Credit Derivatives [Line Items]
Notional amount	¥ 2,092	¥ 2,366
Fair value	26	15
Credit protection written | Investment grade
Credit Derivatives [Line Items]
Notional amount	1,678	1,603
Fair value	23	14
Credit protection written | Non-investment grade
Credit Derivatives [Line Items]
Notional amount	414	763
Fair value	3	1
Credit protection purchased
Credit Derivatives [Line Items]
Notional amount	2,225	2,592
Fair value	¥ (27)	¥ (9)

Derivative Financial Instrume92

Derivative Financial Instruments (Maximum Potential Amount of Future Payments for Credit Protection Written by Expiration Period) (Detail) - JPY (¥) ¥ in Billions	Sep. 30, 2016	Mar. 31, 2016
Credit Derivatives [Line Items]
Maximum payout/Notional amount	¥ 2,092	¥ 2,366
One year or less
Credit Derivatives [Line Items]
Maximum payout/Notional amount	492	538
After one year through five years
Credit Derivatives [Line Items]
Maximum payout/Notional amount	1,336	1,729
After five years
Credit Derivatives [Line Items]
Maximum payout/Notional amount	¥ 264	¥ 99

Derivative Financial Instrume93

Derivative Financial Instruments (Aggregate Fair Value of Derivative Instruments) (Detail) - JPY (¥) ¥ in Billions	Sep. 30, 2016	Mar. 31, 2016
Credit Derivatives [Line Items]
Aggregate fair value of derivative instruments with credit-risk-related contingent features in net liability positions	¥ 815	¥ 790
Collateral provided to counterparties in normal course of business	775	746
Amount required to be posted as collateral or settled immediately if credit-risk-related contingent features were triggered	¥ 40	¥ 44

Commitments and Contingencies94

Commitments and Contingencies (Maximum Exposure or Notional Amount Under Guarantee Contracts) (Detail) - JPY (¥) ¥ in Billions	Sep. 30, 2016	Mar. 31, 2016
Performance guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	¥ 2,065	¥ 2,110
Guarantees on loans
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	252	297
Guarantees on securities
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	176	203
Other guarantees
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	1,559	1,571
Guarantees for repayment of trust principal
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	433	1,141
Liabilities of trust accounts
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	13,828	12,747
Derivative financial instruments
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	¥ 15,264	¥ 15,792

Commitments and Contingencies95

Commitments and Contingencies (Maximum Potential Amount of Future Payments of Certain Guarantees Classified Based on Internal Ratings) (Detail) - Performance guarantees, Guarantees on loans, Guarantees on securities and Other guarantees - JPY (¥) ¥ in Billions		Sep. 30, 2016	Mar. 31, 2016
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount		¥ 4,052	¥ 4,182
Investment grade
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount	[1]	3,075	3,160
Non-investment grade
Guarantor Obligations [Line Items]
Maximum potential/Contractual or Notional amount		¥ 977	¥ 1,022
[1]	Investment grade in the internal rating scale generally corresponds to BBB- or above in the external rating scale.

Commitments and Contingencies96

Commitments and Contingencies (Contractual Amounts With Regard to Undrawn Commitments) (Detail) - JPY (¥) ¥ in Billions		Sep. 30, 2016	Mar. 31, 2016
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance-sheet instruments, contractual amounts of the undrawn commitments		¥ 73,374	¥ 76,190
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]	72,946	75,742
Commercial letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance-sheet instruments, contractual amounts of the undrawn commitments		¥ 428	¥ 448
[1]	Commitments to extend credit include commitments to invest in securities.

Variable Interest Entities an97

Variable Interest Entities and Securitizations (Consolidated Assets of Groups Consolidated VIEs as well as Total Assets and Maximum Exposure to Loss for Its Significant Unconsolidated VIEs) (Detail) - JPY (¥) ¥ in Billions	Sep. 30, 2016	Mar. 31, 2016
Variable Interest Entity [Line Items]
Consolidated VIEs- Consolidated assets	¥ 4,622	¥ 4,692
Significant unconsolidated VIEs- Total assets	4,233	3,072
Significant unconsolidated VIEs- Maximum exposure to loss	684	534
Asset-backed commercial paper/loan programs
Variable Interest Entity [Line Items]
Consolidated VIEs- Consolidated assets	1,860	2,092
Asset-backed securitizations
Variable Interest Entity [Line Items]
Consolidated VIEs- Consolidated assets	677	579
Significant unconsolidated VIEs- Total assets	199	205
Significant unconsolidated VIEs- Maximum exposure to loss	7	13
Investments in securitization products
Variable Interest Entity [Line Items]
Consolidated VIEs- Consolidated assets	336	337
Significant unconsolidated VIEs- Total assets	445	445
Significant unconsolidated VIEs- Maximum exposure to loss	154	154
Investment funds
Variable Interest Entity [Line Items]
Consolidated VIEs- Consolidated assets	1,726	1,660
Significant unconsolidated VIEs- Total assets	3,589	2,422
Significant unconsolidated VIEs- Maximum exposure to loss	523	367
Trust arrangements and other
Variable Interest Entity [Line Items]
Consolidated VIEs- Consolidated assets	¥ 23	¥ 24

Variable Interest Entities an98

Variable Interest Entities and Securitizations (Carrying Amounts and Classification of Assets and Liabilities on MHFG Group's Balance Sheets that Relate to its Variable Interests in Significant Unconsolidated VIEs) (Detail) - JPY (¥) ¥ in Millions		Sep. 30, 2016	Mar. 31, 2016
Assets on balance sheets related to unconsolidated VIEs:
Trading account assets		¥ 30,952,945	¥ 30,020,743
Loans		75,944,728	77,104,122
Total		196,014,723	193,810,151
Liabilities on balance sheets and maximum exposure to loss related to unconsolidated VIEs:
Payables under securities lending transactions		1,534,505	2,844,653
Trading account liabilities		18,970,314	17,111,142
Total		187,749,746	185,626,960
Maximum exposure to loss		684,000	534,000
Unconsolidated VIEs
Assets on balance sheets related to unconsolidated VIEs:
Trading account assets		70,000	55,000
Investments		348,000	254,000
Loans		210,000	205,000
Total		628,000	514,000
Liabilities on balance sheets and maximum exposure to loss related to unconsolidated VIEs:
Payables under securities lending transactions		27,000	27,000
Trading account liabilities		1,000	1,000
Total		28,000	28,000
Maximum exposure to loss	[1]	¥ 684,000	¥ 534,000
[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 an99

Variable Interest Entities and Securitizations - Additional Information (Detail) - JPY (¥) ¥ in Millions	Sep. 30, 2016	Apr. 01, 2016	Mar. 31, 2016
Variable Interest Entity [Line Items]
Total assets	¥ 196,014,723		¥ 193,810,151
Noncontrolling interests	161,794		168,640
Total liabilities	187,749,746		185,626,960
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	224,000		243,000
Assets associated with loan participation transactions
Variable Interest Entity [Line Items]
Transferred assets continue to be carried on the consolidated balance sheets	¥ 48,000		¥ 64,000

Fair Value - Additional Informa

Fair Value - Additional Information (Detail) - JPY (¥) ¥ in Billions	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Mar. 31, 2016
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Carrying amounts of other equity interests of which fair value is not readily determinable	¥ 301		¥ 313
Senior borrowings and bonds
Fair Value, Estimate Not Practicable, Financial Statement Captions [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	22		¥ 20
Net unrealized gains (losses) resulting from changes in fair values of the notes	2	¥ 28
Long-term debt
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Fair value of liabilities transferred into Level 3		1
Fair value of liabilities transferred out of Level 3	12	1
Trading securities sold, not yet purchased
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Fair value of liabilities transferred into Level 3	1
Trading securities
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Fair value of assets transferred into Level 3	280	8
Fair value of assets transferred out of Level 3	¥ 2	20
Available-for-sale securities
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Fair value of assets transferred into Level 3		¥ 23
Investment funds
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Underlying assets, estimated remaining liquidation period	10 years

Fair Value (Assets and Liabilit

Fair Value (Assets and Liabilities Measured at Fair Value on Recurring Basis Including those for Which MHFG Group has Elected Fair Value Option) (Detail) - JPY (¥) ¥ in Millions		Sep. 30, 2016	Mar. 31, 2016
Assets:
Available-for-sale securities		¥ 20,312,495	¥ 25,452,525
Liabilities:
Long-term debt		1,529,681	1,055,626
Fair Value, Measurements, Recurring
Assets:
Other investments		37,000	42,000
Total assets measured at fair value		51,303,000	55,516,000
Liabilities:
Trading securities sold, not yet purchased		2,676,000	2,630,000
Long-term debt	[1]	1,530,000	1,056,000
Total liabilities measured at fair value		20,500,000	18,167,000
Fair Value, Measurements, Recurring | Trading securities
Assets:
Securities measured at net asset value	[2]	576,000	617,000
Fair Value, Measurements, Recurring | Available-for-sale securities
Assets:
Securities measured at net asset value	[2]	95,000	65,000
Fair Value, Measurements, Recurring | Interest rate contracts
Assets:
Assets, derivatives		13,767,000	11,522,000
Liabilities:
Liabilities, derivatives		13,339,000	11,269,000
Fair Value, Measurements, Recurring | Foreign exchange contracts
Assets:
Assets, derivatives		3,133,000	3,130,000
Liabilities:
Liabilities, derivatives		2,730,000	2,980,000
Fair Value, Measurements, Recurring | Equity-related contracts
Assets:
Assets, derivatives		153,000	170,000
Liabilities:
Liabilities, derivatives		152,000	140,000
Fair Value, Measurements, Recurring | Credit-related contracts
Assets:
Assets, derivatives		31,000	43,000
Liabilities:
Liabilities, derivatives		32,000	37,000
Fair Value, Measurements, Recurring | Other contracts
Assets:
Assets, derivatives		45,000	59,000
Liabilities:
Liabilities, derivatives		41,000	55,000
Fair Value, Measurements, Recurring | Japanese government bonds
Assets:
Assets, trading securities	[3]	2,421,000	2,303,000
Available-for-sale securities		10,371,000	15,763,000
Fair Value, Measurements, Recurring | Japanese local government bonds
Assets:
Assets, trading securities	[3]	51,000	79,000
Available-for-sale securities		281,000	241,000
Fair Value, Measurements, Recurring | U.S. Treasury bonds and federal agency securities
Assets:
Assets, trading securities	[3]	3,026,000	3,806,000
Available-for-sale securities		904,000	438,000
Fair Value, Measurements, Recurring | Other foreign government bonds
Assets:
Assets, trading securities	[3]	2,032,000	2,565,000
Available-for-sale securities		929,000	942,000
Fair Value, Measurements, Recurring | Agency mortgage-backed securities
Assets:
Assets, trading securities	[3]	1,953,000	1,558,000
Available-for-sale securities		912,000	949,000
Fair Value, Measurements, Recurring | Residential mortgage-backed securities
Assets:
Assets, trading securities	[3]	17,000	21,000
Available-for-sale securities		169,000	210,000
Fair Value, Measurements, Recurring | Commercial mortgage-backed securities
Assets:
Assets, trading securities	[3]	2,000	4,000
Available-for-sale securities		198,000	187,000
Fair Value, Measurements, Recurring | Certificates of deposit and commercial paper
Assets:
Assets, trading securities	[3]	617,000	881,000
Fair Value, Measurements, Recurring | Corporate bonds and other debt securities
Assets:
Assets, trading securities	[3]	2,284,000	2,422,000
Fair Value, Measurements, Recurring | Equity securities
Assets:
Assets, trading securities	[3]	845,000	841,000
Fair Value, Measurements, Recurring | Japanese corporate bonds and other debt securities
Assets:
Available-for-sale securities		2,107,000	2,095,000
Fair Value, Measurements, Recurring | Foreign corporate bonds and other debt securities
Assets:
Available-for-sale securities		795,000	847,000
Fair Value, Measurements, Recurring | Equity securities (marketable)
Assets:
Available-for-sale securities		3,552,000	3,716,000
Fair Value, Measurements, Recurring | Level 1
Assets:
Total assets measured at fair value		23,943,000	29,833,000
Liabilities:
Trading securities sold, not yet purchased		2,422,000	2,482,000
Total liabilities measured at fair value		2,576,000	2,666,000
Fair Value, Measurements, Recurring | Level 1 | Interest rate contracts
Assets:
Assets, derivatives		70,000	97,000
Liabilities:
Liabilities, derivatives		73,000	98,000
Fair Value, Measurements, Recurring | Level 1 | Foreign exchange contracts
Assets:
Assets, derivatives		24,000	23,000
Liabilities:
Liabilities, derivatives		19,000	26,000
Fair Value, Measurements, Recurring | Level 1 | Equity-related contracts
Assets:
Assets, derivatives		42,000	46,000
Liabilities:
Liabilities, derivatives		62,000	60,000
Fair Value, Measurements, Recurring | Level 1 | Other contracts
Assets:
Assets, derivatives		1,000
Fair Value, Measurements, Recurring | Level 1 | Japanese government bonds
Assets:
Assets, trading securities	[3]	2,404,000	2,272,000
Available-for-sale securities		9,624,000	15,037,000
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury bonds and federal agency securities
Assets:
Assets, trading securities	[3]	2,930,000	3,729,000
Available-for-sale securities		904,000	438,000
Fair Value, Measurements, Recurring | Level 1 | Other foreign government bonds
Assets:
Assets, trading securities	[3]	1,697,000	2,192,000
Available-for-sale securities		374,000	352,000
Fair Value, Measurements, Recurring | Level 1 | Agency mortgage-backed securities
Assets:
Assets, trading securities	[3]	1,381,000	995,000
Available-for-sale securities		168,000	169,000
Fair Value, Measurements, Recurring | Level 1 | Corporate bonds and other debt securities
Assets:
Assets, trading securities	[3]	5,000	9,000
Fair Value, Measurements, Recurring | Level 1 | Equity securities
Assets:
Assets, trading securities	[3]	767,000	758,000
Fair Value, Measurements, Recurring | Level 1 | Equity securities (marketable)
Assets:
Available-for-sale securities		3,552,000	3,716,000
Fair Value, Measurements, Recurring | Level 2
Assets:
Total assets measured at fair value		24,968,000	23,496,000
Liabilities:
Trading securities sold, not yet purchased		253,000	148,000
Long-term debt	[1]	939,000	433,000
Total liabilities measured at fair value		17,259,000	14,809,000
Fair Value, Measurements, Recurring | Level 2 | Interest rate contracts
Assets:
Assets, derivatives		13,672,000	11,396,000
Liabilities:
Liabilities, derivatives		13,263,000	11,168,000
Fair Value, Measurements, Recurring | Level 2 | Foreign exchange contracts
Assets:
Assets, derivatives		3,102,000	3,099,000
Liabilities:
Liabilities, derivatives		2,710,000	2,953,000
Fair Value, Measurements, Recurring | Level 2 | Equity-related contracts
Assets:
Assets, derivatives		90,000	95,000
Liabilities:
Liabilities, derivatives		59,000	56,000
Fair Value, Measurements, Recurring | Level 2 | Credit-related contracts
Assets:
Assets, derivatives		28,000	40,000
Liabilities:
Liabilities, derivatives		29,000	33,000
Fair Value, Measurements, Recurring | Level 2 | Other contracts
Assets:
Assets, derivatives		8,000	21,000
Liabilities:
Liabilities, derivatives		6,000	18,000
Fair Value, Measurements, Recurring | Level 2 | Japanese government bonds
Assets:
Assets, trading securities	[3]	17,000	31,000
Available-for-sale securities		747,000	726,000
Fair Value, Measurements, Recurring | Level 2 | Japanese local government bonds
Assets:
Assets, trading securities	[3]	51,000	79,000
Available-for-sale securities		281,000	241,000
Fair Value, Measurements, Recurring | Level 2 | U.S. Treasury bonds and federal agency securities
Assets:
Assets, trading securities	[3]	96,000	77,000
Fair Value, Measurements, Recurring | Level 2 | Other foreign government bonds
Assets:
Assets, trading securities	[3]	335,000	373,000
Available-for-sale securities		555,000	590,000
Fair Value, Measurements, Recurring | Level 2 | Agency mortgage-backed securities
Assets:
Assets, trading securities	[3]	572,000	563,000
Available-for-sale securities		744,000	780,000
Fair Value, Measurements, Recurring | Level 2 | Residential mortgage-backed securities
Assets:
Available-for-sale securities		69,000	87,000
Fair Value, Measurements, Recurring | Level 2 | Commercial mortgage-backed securities
Assets:
Assets, trading securities	[3]	2,000	2,000
Fair Value, Measurements, Recurring | Level 2 | Certificates of deposit and commercial paper
Assets:
Assets, trading securities	[3]	617,000	881,000
Fair Value, Measurements, Recurring | Level 2 | Corporate bonds and other debt securities
Assets:
Assets, trading securities	[3]	1,303,000	1,693,000
Fair Value, Measurements, Recurring | Level 2 | Equity securities
Assets:
Assets, trading securities	[3]	60,000	62,000
Fair Value, Measurements, Recurring | Level 2 | Japanese corporate bonds and other debt securities
Assets:
Available-for-sale securities		1,931,000	1,921,000
Fair Value, Measurements, Recurring | Level 2 | Foreign corporate bonds and other debt securities
Assets:
Available-for-sale securities		688,000	739,000
Fair Value, Measurements, Recurring | Level 3
Assets:
Other investments		37,000	42,000
Total assets measured at fair value		1,721,000	1,505,000
Liabilities:
Trading securities sold, not yet purchased		1,000
Long-term debt	[1]	591,000	623,000
Total liabilities measured at fair value		665,000	692,000
Fair Value, Measurements, Recurring | Level 3 | Interest rate contracts
Assets:
Assets, derivatives		25,000	29,000
Liabilities:
Liabilities, derivatives		3,000	3,000
Fair Value, Measurements, Recurring | Level 3 | Foreign exchange contracts
Assets:
Assets, derivatives		7,000	8,000
Liabilities:
Liabilities, derivatives		1,000	1,000
Fair Value, Measurements, Recurring | Level 3 | Equity-related contracts
Assets:
Assets, derivatives		21,000	29,000
Liabilities:
Liabilities, derivatives		31,000	24,000
Fair Value, Measurements, Recurring | Level 3 | Credit-related contracts
Assets:
Assets, derivatives		3,000	3,000
Liabilities:
Liabilities, derivatives		3,000	4,000
Fair Value, Measurements, Recurring | Level 3 | Other contracts
Assets:
Assets, derivatives		36,000	38,000
Liabilities:
Liabilities, derivatives		35,000	37,000
Fair Value, Measurements, Recurring | Level 3 | Residential mortgage-backed securities
Assets:
Assets, trading securities	[3]	17,000	21,000
Available-for-sale securities		100,000	123,000
Fair Value, Measurements, Recurring | Level 3 | Commercial mortgage-backed securities
Assets:
Assets, trading securities	[3]		2,000
Available-for-sale securities		198,000	187,000
Fair Value, Measurements, Recurring | Level 3 | Corporate bonds and other debt securities
Assets:
Assets, trading securities	[3]	976,000	720,000
Fair Value, Measurements, Recurring | Level 3 | Equity securities
Assets:
Assets, trading securities	[3]	18,000	21,000
Fair Value, Measurements, Recurring | Level 3 | Japanese corporate bonds and other debt securities
Assets:
Available-for-sale securities		176,000	174,000
Fair Value, Measurements, Recurring | Level 3 | Foreign corporate bonds and other debt securities
Assets:
Available-for-sale securities		¥ 107,000	¥ 108,000
[1]	Amounts represent items for which the 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 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, 2016 and September 30, 2016 were ¥30 billion and ¥28 billion, respectively.
[3]	Trading securities include foreign currency denominated securities for which the MHFG Group elected the fair value option.

Fair Value (Assets and Liabi102

Fair Value (Assets and Liabilities Measured at Fair Value on Recurring Basis Including those for Which MHFG Group has Elected Fair Value Option) (Parenthetical) (Detail) - JPY (¥) ¥ in Billions	Sep. 30, 2016	Mar. 31, 2016
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unfunded commitments	¥ 28	¥ 30

Fair Value (Reconciliation for

Fair Value (Reconciliation for All Assets and Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs Level 3) (Detail) - JPY (¥) ¥ in Billions		6 Months Ended
		Sep. 30, 2016	Sep. 30, 2015
Trading securities sold, not yet purchased
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Gains (losses) in OCI		¥ 0	¥ 0
Transfers into Level 3		1
Purchases		(32)	(1)
Sales		32	1
Ending Balance		1
Long-term debt
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		623	587
Gains (losses) in Earnings	[1]	9	27
Gains (losses) in OCI		0	0
Transfers into Level 3			1
Transfers out of level 3		(12)	(1)
Issuances		147	160
Settlements		(158)	(139)
Ending Balance		591	581
Change in unrealized gain (losses) still held	[2]	5	27
Other investments
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		42	53
Gains (losses) in Earnings	[3]	(3)	8
Purchases		11	1
Sales			(19)
Issuances		0	0
Settlements		(13)	(2)
Ending Balance		37	41
Change in unrealized gain (losses) still held	[2]	(1)	(7)
Trading securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers into Level 3		280	8
Transfers out of level 3		(2)	(20)
Trading securities | Other foreign government bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Purchases			1
Sales			(1)
Issuances			0
Trading securities | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		21	29
Issuances		0	0
Settlements		(4)	(5)
Ending Balance		17	24
Trading securities | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		2	4
Issuances		0	0
Settlements		(2)	(1)
Ending Balance			3
Trading securities | Corporate bonds and other debt securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		720	639
Gains (losses) in Earnings	[4]	(53)	(4)
Transfers into Level 3		280	8
Transfers out of level 3		(2)	(20)
Purchases		343	233
Sales		(241)	(88)
Issuances		0	0
Settlements		(71)	(40)
Ending Balance		976	728
Change in unrealized gain (losses) still held	[2]	(39)	(5)
Trading securities | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		21	23
Gains (losses) in Earnings	[4]	4	(2)
Sales		(7)	(1)
Issuances		0	0
Ending Balance		18	20
Change in unrealized gain (losses) still held	[2]	4	(2)
Derivative assets | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[5]	26	18
Gains (losses) in Earnings	[4],[5]	(4)	(6)
Issuances	[5]	0	0
Settlements	[5]		6
Ending Balance	[5]	22	18
Change in unrealized gain (losses) still held	[2],[5]	(3)	(5)
Derivative assets | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[5]	7	8
Gains (losses) in Earnings	[4],[5]	6	4
Issuances	[5]	0	0
Settlements	[5]	(7)	(4)
Ending Balance	[5]	6	8
Change in unrealized gain (losses) still held	[2],[5]		(1)
Derivative assets | Equity-related contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[5]	5	(14)
Gains (losses) in Earnings	[4],[5]	(13)	15
Issuances	[5]	0	0
Settlements	[5]	(2)
Ending Balance	[5]	(10)	1
Change in unrealized gain (losses) still held	[2],[5]	(19)	12
Derivative assets | Credit-related contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[5]	(1)	(1)
Gains (losses) in Earnings	[4],[5]	1
Issuances	[5]	0	0
Settlements	[5]		1
Derivative assets | Other contracts
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[5]	1
Issuances	[5]	0
Ending Balance	[5]	1
Available-for-sale securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers into Level 3			23
Available-for-sale securities | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		123	166
Sales		(1)	(4)
Issuances		0	0
Settlements		(22)	(22)
Ending Balance		100	140
Available-for-sale securities | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		187	169
Purchases		20	56
Sales			(37)
Issuances		0	0
Settlements		(9)	(5)
Ending Balance		198	183
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		174	155
Gains (losses) in Earnings	[3]		1
Gains (losses) in OCI	[6]	22	7
Purchases		1	55
Sales		(4)	(3)
Issuances		0	0
Settlements		(17)	(23)
Ending Balance		176	192
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		108	85
Gains (losses) in Earnings	[3]	1	1
Gains (losses) in OCI	[6]	(7)	(6)
Transfers into Level 3			23
Purchases		10	37
Issuances		0	0
Settlements		(5)	(23)
Ending Balance		¥ 107	¥ 117
[1]	Gains (losses) in Earnings are reported in Other noninterest income (expenses).
[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 September 30, 2015 and 2016.
[3]	Gains (losses) in Earnings are reported in Investment gains (losses)-net.
[4]	Gains (losses) in Earnings are reported in Trading account gains (losses)-net, Foreign exchange gains (losses)-net or Other noninterest income (expenses).
[5]	Total Level 3 derivative exposures have been netted on the table for presentation purposes only.
[6]	Gains (losses) in OCI are reported in Other comprehensive income (loss).

Fair Value (Quantitative Inform

Fair Value (Quantitative Information About Level Three Fair Value Measurements) (Detail) - JPY (¥) ¥ in Billions		6 Months Ended	12 Months Ended
		Sep. 30, 2016	Mar. 31, 2016
Available For Sale And Trading Securities | Residential mortgage-backed securities
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value		¥ 117	¥ 144
Principal valuation technique		Discounted cash flow Price-based
Available For Sale And Trading Securities | Residential mortgage-backed securities | Discounted Cash Flow Method Or Transaction Price Valuation Technique | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Prepayment rate		3.00%	3.00%
Default rate		0.00%	0.00%
Recovery rate		100.00%	100.00%
Discount margin		0.15%	0.13%
Available For Sale And Trading Securities | Residential mortgage-backed securities | Discounted Cash Flow Method Or Transaction Price Valuation Technique | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Prepayment rate		19.00%	19.00%
Default rate		2.00%	2.00%
Recovery rate		100.00%	100.00%
Discount margin		1.70%	1.80%
Available For Sale And Trading Securities | Residential mortgage-backed securities | Discounted Cash Flow Method Or Transaction Price Valuation Technique | Weighted Average
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Prepayment rate	[1]	7.00%	7.00%
Default rate	[1]	0.00%	0.00%
Recovery rate	[1]	100.00%	100.00%
Discount margin	[1]	0.59%	0.60%
Available For Sale And Trading Securities | Commercial mortgage-backed securities
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value		¥ 198	¥ 189
Principal valuation technique		Discounted cash flow Price-based
Available For Sale And Trading Securities | Commercial mortgage-backed securities | Discounted Cash Flow Method Or Transaction Price Valuation Technique | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount margin		0.04%	0.06%
Available For Sale And Trading Securities | Commercial mortgage-backed securities | Discounted Cash Flow Method Or Transaction Price Valuation Technique | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount margin		1.84%	5.80%
Available For Sale And Trading Securities | Commercial mortgage-backed securities | Discounted Cash Flow Method Or Transaction Price Valuation Technique | Weighted Average
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount margin	[1]	0.30%	0.37%
Available For Sale And Trading Securities | Corporate bonds and other debt securities
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value		¥ 1,259	¥ 1,002
Principal valuation technique		Discounted cash flow Price-based
Available For Sale And Trading Securities | Corporate bonds and other debt securities | Discounted Cash Flow Method Or Transaction Price Valuation Technique | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Prepayment rate	[2]	14.00%	0.00%
Default rate	[2]	1.00%	0.00%
Recovery rate	[2]	60.00%	60.00%
Discount margin	[2]	0.13%	0.11%
Available For Sale And Trading Securities | Corporate bonds and other debt securities | Discounted Cash Flow Method Or Transaction Price Valuation Technique | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Prepayment rate	[2]	23.00%	21.00%
Default rate	[2]	2.00%	2.00%
Recovery rate	[2]	69.00%	69.00%
Discount margin	[2]	11.09%	11.15%
Available For Sale And Trading Securities | Corporate bonds and other debt securities | Discounted Cash Flow Method Or Transaction Price Valuation Technique | Weighted Average
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Prepayment rate	[1],[2]	22.00%	19.00%
Default rate	[1],[2]	2.00%	2.00%
Recovery rate	[1],[2]	68.00%	68.00%
Discount margin	[1],[2]	1.33%	1.51%
Available For Sale And Trading Securities | Japanese corporate bonds and foreign corporate bonds | Discounted Cash Flow Method Or Transaction Price Valuation Technique | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount margin	[3]	(0.32%)	0.10%
Available For Sale And Trading Securities | Japanese corporate bonds and foreign corporate bonds | Discounted Cash Flow Method Or Transaction Price Valuation Technique | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount margin	[3]	29.87%	38.50%
Available For Sale And Trading Securities | Japanese corporate bonds and foreign corporate bonds | Discounted Cash Flow Method Or Transaction Price Valuation Technique | Weighted Average
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount margin	[1],[3]	4.22%	4.54%
Derivative contracts | Interest rate contracts
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value		¥ 22	¥ 26
Principal valuation technique	[4]	Internal valuation model
Derivative contracts | Interest rate contracts | Internal Valuation Model | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
IR - IR correlation		23.00%	32.00%
Default rate	[5]	0.00%	0.00%
Derivative contracts | Interest rate contracts | Internal Valuation Model | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
IR - IR correlation		100.00%	100.00%
Default rate	[5]	63.00%	63.00%
Derivative contracts | Foreign exchange contracts
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value		¥ 6	¥ 7
Principal valuation technique	[4]	Internal valuation model
Derivative contracts | Foreign exchange contracts | Internal Valuation Model | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
FX - IR correlation		1.00%	5.00%
FX - FX correlation		55.00%	54.00%
Default rate	[5]	0.00%	0.00%
Derivative contracts | Foreign exchange contracts | Internal Valuation Model | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
FX - IR correlation		50.00%	50.00%
FX - FX correlation		55.00%	54.00%
Default rate	[5]	63.00%	63.00%
Derivative contracts | Equity-related contracts
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value		¥ (10)	¥ 5
Principal valuation technique	[4]	Internal valuation model
Derivative contracts | Equity-related contracts | Internal Valuation Model | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Equity - IR correlation		25.00%	30.00%
Equity - FX correlation		55.00%	55.00%
Equity volatility		6.00%	10.00%
Derivative contracts | Equity-related contracts | Internal Valuation Model | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Equity - IR correlation		25.00%	30.00%
Equity - FX correlation		55.00%	55.00%
Equity volatility		48.00%	40.00%
Derivative contracts | Credit-related contracts
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value			¥ (1)
Principal valuation technique	[4]	Internal valuation model
Derivative contracts | Credit-related contracts | Internal Valuation Model | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Default rate		0.00%	0.00%
Credit correlation		28.00%	29.00%
Derivative contracts | Credit-related contracts | Internal Valuation Model | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Default rate		59.00%	42.00%
Credit correlation		100.00%	100.00%
Long-term debt
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value		¥ 591	¥ 623
Principal valuation technique	[4]	Internal valuation model
Long-term debt | Internal Valuation Model | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
IR - IR correlation		23.00%	32.00%
FX - IR correlation		1.00%	5.00%
FX - FX correlation		55.00%	54.00%
Default rate		0.00%	0.00%
Equity - IR correlation		25.00%	30.00%
Credit correlation		34.00%	28.00%
Equity - FX correlation		55.00%	55.00%
Equity volatility		7.00%	14.00%
Equity correlation		18.00%	18.00%
Long-term debt | Internal Valuation Model | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
IR - IR correlation		100.00%	100.00%
FX - IR correlation		50.00%	50.00%
FX - FX correlation		55.00%	54.00%
Default rate		3.00%	5.00%
Equity - IR correlation		25.00%	30.00%
Credit correlation		100.00%	100.00%
Equity - FX correlation		55.00%	55.00%
Equity volatility		42.00%	39.00%
Equity correlation		100.00%	100.00%
[1]	Weighted averages are calculated by weighting each input by the relative fair value of the respective financial instruments.
[2]	These inputs are mainly used for determining the fair values of securitization products such as CDO, CLO and ABS, other than RMBS and CMBS.
[3]	This input is mainly used for determining the fair values of Japanese corporate bonds and foreign corporate bonds.
[4]	Internal valuation model includes discounted cash flow models and the Black-Scholes option pricing model.
[5]	This input represents the counterparty default rate derived from the MHFG Group's own internal credit analyses.

Fair Value (Fair Value Hierarch

Fair Value (Fair Value Hierarchy for Assets and Liabilities Measured on Nonrecurring Basis) (Detail) - Fair Value, Measurements, Nonrecurring - JPY (¥) ¥ in Billions	Sep. 30, 2016	Mar. 31, 2016
Assets:
Loans	¥ 118	¥ 124
Loans held-for-sale	4	13
Other investments	5	1
Total assets measured at fair value	127	138
Level 1
Assets:
Other investments	4
Total assets measured at fair value	4
Level 2
Assets:
Loans held-for-sale	4	7
Total assets measured at fair value	4	7
Level 3
Assets:
Loans	118	124
Loans held-for-sale		6
Other investments	1	1
Total assets measured at fair value	119	131
Aggregate cost
Assets:
Loans	185	197
Loans held-for-sale	4	14
Other investments	9	2
Premises and equipment-net		1
Goodwill		6
Total assets measured at fair value	¥ 198	¥ 220

Fair Value (Carrying Amounts an

Fair Value (Carrying Amounts and Fair Values of Certain Financial Instruments Excluding Financial Instruments Which Are Carried at Fair Value on a Recurring Basis and Those Outside Scope of Asc 825) (Detail) - JPY (¥) ¥ in Millions		Sep. 30, 2016	Mar. 31, 2016
Financial liabilities:
Long-term debt		¥ 1,529,681	¥ 1,055,626
Carrying amount
Financial assets:
Cash and due from banks, call loans and funds sold, and receivables under resale agreements and securities borrowing transactions		56,658,000	48,757,000
Investments		4,260,000	4,819,000
Loans, net of allowance for loan losses	[1]	75,821,000	77,040,000
Financial liabilities:
Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions		39,580,000	39,908,000
Interest-bearing deposits		101,793,000	100,228,000
Due to trust accounts		3,425,000	4,467,000
Other short-term borrowings		1,556,000	2,080,000
Long-term debt		13,709,000	13,691,000
Estimated fair value
Financial assets:
Cash and due from banks, call loans and funds sold, and receivables under resale agreements and securities borrowing transactions		56,658,000	48,757,000
Investments		4,318,000	4,873,000
Loans, net of allowance for loan losses	[1]	76,945,000	78,241,000
Financial liabilities:
Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions		39,580,000	39,908,000
Interest-bearing deposits		101,803,000	100,234,000
Due to trust accounts		3,425,000	4,467,000
Other short-term borrowings		1,556,000	2,080,000
Long-term debt		13,865,000	13,863,000
Estimated fair value | Level 1
Financial assets:
Cash and due from banks, call loans and funds sold, and receivables under resale agreements and securities borrowing transactions		942,000	923,000
Investments		4,318,000	4,873,000
Financial liabilities:
Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions		17,948,000	17,223,000
Interest-bearing deposits		47,587,000	46,207,000
Estimated fair value | Level 2
Financial assets:
Cash and due from banks, call loans and funds sold, and receivables under resale agreements and securities borrowing transactions		55,716,000	47,834,000
Financial liabilities:
Noninterest-bearing deposits, call money and funds purchased, and payables under repurchase agreements and securities lending transactions		21,632,000	22,685,000
Interest-bearing deposits		54,216,000	54,027,000
Due to trust accounts		3,425,000	4,467,000
Other short-term borrowings		1,556,000	2,080,000
Long-term debt		12,950,000	12,969,000
Estimated fair value | Level 3
Financial assets:
Loans, net of allowance for loan losses	[1]	76,945,000	78,241,000
Financial liabilities:
Long-term debt		¥ 915,000	¥ 894,000
[1]	Loans, net of allowance for loan losses include items measured at fair value on a nonrecurring basis.

Offsetting of Financial Asse107

Offsetting of Financial Assets and Financial Liabilities (Information of Offsetting of Financial Assets and Financial Liabilities) (Detail) - JPY (¥) ¥ in Billions		Sep. 30, 2016	Mar. 31, 2016
Offsetting Financial Assets And Financial Liabilities [Line Items]
Derivative assets, Gross amounts recognized	[1]	¥ 15,916	¥ 14,130
Derivative assets, Gross amounts offset on the balance sheet	[1]	0	0
Derivative assets, Net amounts presented on the balance sheet	[1],[2]	15,916	14,130
Derivative assets, Amounts not offset on the balance sheet, Financial instruments	[1],[3],[4]	(13,562)	(12,167)
Derivative assets, Amounts not offset on the balance sheet, Cash collateral	[1],[3]	(709)	(599)
Derivative assets, Net amounts	[1]	1,645	1,364
Receivables under resale agreements, Gross amounts recognized	[1]	9,068	7,490
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]	9,068	7,490
Receivables under resale agreements, Amounts not offset on the balance sheet, Financial instruments	[1],[3],[4]	(9,028)	(7,461)
Receivables under resale agreements, Amounts not offset on the balance sheet, Cash collateral	[1],[3]	0	0
Receivables under resale agreements, Net amounts	[1]	40	29
Receivables under securities borrowing transactions, Gross amounts recognized	[1]	3,060	3,327
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]	3,060	3,327
Receivables under securities borrowing transactions, Amounts not offset on the balance sheet, Financial instruments	[1],[3],[4]	(3,046)	(3,318)
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]	14	9
Financial assets, Gross amounts recognized, Total	[1]	28,044	24,947
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]	28,044	24,947
Financial assets, Amounts not offset on the balance sheet, Financial instruments, Total	[1],[3],[4]	(25,636)	(22,946)
Financial assets, Amounts not offset on the balance sheet, Cash collateral, Total	[1],[3]	(709)	(599)
Financial assets, Net amounts, Total	[1]	1,699	1,402
Derivative liabilities, Gross amounts recognized	[1]	15,152	13,652
Derivative liabilities, Gross amounts offset on the balance sheet	[1]	0	0
Derivative liabilities, Net amounts presented on the balance sheet	[1],[2]	15,152	13,652
Derivative liabilities, Amounts not offset on the balance sheet, Financial instruments	[1],[3],[4]	(13,471)	(12,043)
Derivative liabilities, Amounts not offset on the balance sheet, Cash collateral	[1],[3]	(910)	(748)
Derivative liabilities, Net amounts	[1]	771	861
Payables under repurchase agreements, Gross amounts recognized	[1]	17,250	16,507
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]	17,250	16,507
Payables under repurchase agreements, Amounts not offset on the balance sheet, Financial instruments	[1],[3],[4]	(17,142)	(16,464)
Payables under repurchase agreements, Amounts not offset on the balance sheet, Cash collateral	[1],[3]	0	0
Payables under repurchase agreements, Net amounts	[1]	108	43
Payables under securities lending transactions, Gross amounts recognized	[1]	1,188	2,538
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]	1,188	2,538
Payables under securities lending transactions, Amounts not offset on the balance sheet, Financial instruments	[1],[3],[4]	(1,180)	(2,531)
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]	8	7
Financial liabilities, Gross amounts recognized, Total	[1]	33,590	32,697
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]	33,590	32,697
Financial liabilities, Amounts not offset on the balance sheet, Financial instruments, Total	[1],[3],[4]	(31,793)	(31,038)
Financial liabilities, Amounts not offset on the balance sheet, Cash collateral, Total	[1],[3]	(910)	(748)
Financial liabilities, Net amounts, Total	[1]	¥ 887	¥ 911
[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") andOTC-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 Se108

Repurchase Agreements and Securities Lending Transactions Accounted for as Secured Borrowings (Gross Amounts of Liabilities Associated with Repurchase Agreements and Securities Lending Transactions by Remaining Contractual Maturity) (Detail) - JPY (¥) ¥ in Billions		Sep. 30, 2016	Mar. 31, 2016
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	[1]	¥ 17,739	¥ 16,833
Securities lending transactions	[1]	1,535	2,845
Total		19,274	19,678
Overnight and continuous
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements		327	6,289
Securities lending transactions		182	1,909
Total		509	8,198
Up to 30 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements		12,847	6,125
Securities lending transactions		1,133	700
Total		13,980	6,825
31 to 90 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements		3,362	3,582
Total		3,362	3,582
Greater than 90 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements		1,203	837
Securities lending transactions		220	236
Total		¥ 1,423	¥ 1,073
[1]	Amounts exceeded the gross amounts recognized in Note 18 "Offsetting of financial assets and financial liabilities" by ¥633 billion and ¥836 billion, at March 31, 2016 and September 30, 2016, 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 Se109

Repurchase Agreements and Securities Lending Transactions Accounted for as Secured Borrowings (Gross Amounts of Liabilities Associated with Repurchase Agreements and Securities Lending Transactions by Class of Underlying Collateral) (Detail) - JPY (¥) ¥ in Billions		Sep. 30, 2016	Mar. 31, 2016
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	[1]	¥ 17,739	¥ 16,833
Securities lending transactions	[1]	1,535	2,845
Japanese government bonds and Japanese local government bonds
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements		634	532
Securities lending transactions		717	1,891
Foreign government bonds and foreign agency mortgage-backed securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements		16,087	15,781
Securities lending transactions		579	700
Commercial Paper and Corporate Bonds
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements		486	221
Securities lending transactions		29	27
Equity Securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements		380	141
Securities lending transactions		182	185
Other securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements		152	158
Securities lending transactions		¥ 28	¥ 42
[1]	Amounts exceeded the gross amounts recognized in Note 18 "Offsetting of financial assets and financial liabilities" by ¥633 billion and ¥836 billion, at March 31, 2016 and September 30, 2016, 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 Se110

Repurchase Agreements and Securities Lending Transactions Accounted for as Secured Borrowings (Gross Amounts of Liabilities Associated with Repurchase Agreements and Securities Lending Transactions by Class of Underlying Collateral) (Parenthetical) (Detail) - JPY (¥) ¥ in Billions	Sep. 30, 2016	Mar. 31, 2016
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	¥ 836	¥ 633

Business Segment Information (I

Business Segment Information (Information for Reportable Segments) (Detail) - JPY (¥) ¥ in Billions		6 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	[1]
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits		¥ 1,089.7	¥ 1,131.8
General and administrative expenses		680.5	672.3
Others		(6)	(12.8)
Net business profits (losses)	[2]	403.2	446.7
Retail And Business Banking Company
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits		310.8	332.1
General and administrative expenses		338.8	331.1
Net business profits (losses)	[2]	(28)	1
Corporate And Institutional Company
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits		223.2	209.5
General and administrative expenses		92.9	91.3
Net business profits (losses)	[2]	130.3	118.2
Global Corporate Company
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits		192.7	204.8
General and administrative expenses		115.5	111.6
Net business profits (losses)	[2]	77.2	93.2
Global Markets Company
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits		334.3	332.3
General and administrative expenses		94.6	88.5
Net business profits (losses)	[2]	239.7	243.8
Asset Management Company
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits		24.5	26.6
General and administrative expenses		15	15
Net business profits (losses)	[2]	9.5	11.6
Others
Japan Gaap Schedule of Segment Reporting Information, by Segment [Line Items]
Gross profits	[3]	4.2	26.5
General and administrative expenses	[3]	23.7	34.8
Others	[3]	(6)	(12.8)
Net business profits (losses)	[2],[3]	¥ (25.5)	¥ (21.1)
[1]	Following the introduction of an in-house company system based on customer segments in April 2016, segment information for the earlier period was restated to reflect the relevant changes.
[2]	Net business profits is used in Japan as a measure of the profitability of core banking operations, and is defined as gross profits (or the sum of net interest income, fiduciary income, net fee and commission income, net trading income and net other operating income) less general and administrative expenses. 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.

Business Segment Information (R

Business Segment Information (Reconciliation of Total Net Business Profits Under Internal Management Reporting System to Income Loss Before Income Tax Expense Benefit Shown on Consolidated Statements of Income) (Detail) - JPY (¥) ¥ in Millions		6 Months Ended
		Sep. 30, 2016	Sep. 30, 2015
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net business profits	[1]	¥ 403,200	¥ 446,700	[2]
U.S. GAAP adjustments		14,800	(67,600)
(Provision) credit for loan losses		(569)	(3,030)
Net gains (losses) related to equity investments		64,500	122,600
Non-recurring personnel expense		(4,700)	(800)
Gains on disposal of premises and equipment		3,486	8,756
(Provision) credit for losses on off-balance-sheet instruments		7,895	9,324
Others-net		(31,300)	26,500
Income before income tax expense		¥ 457,273	¥ 542,530
[1]	Net business profits is used in Japan as a measure of the profitability of core banking operations, and is defined as gross profits (or the sum of net interest income, fiduciary income, net fee and commission income, net trading income and net other operating income) less general and administrative expenses. Measurement of net business profits is required for regulatory reporting to the Financial Services Agency.
[2]	Following the introduction of an in-house company system based on customer segments in April 2016, segment information for the earlier period was restated to reflect the relevant changes.

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - Subsequent Event ¥ in Billions	Oct. 01, 2016JPY (¥)shares
MHAM
Subsequent Event [Line Items]
Interests exchanged	30.00%
DIAM
Subsequent Event [Line Items]
Fair value of MHFG's equity interests in DIAM held before the business combination	¥ 72
Common shares of MHAM | shares	1,038,408
Fair value of total consideration transferred	¥ 29
Remeasuresment gain recognized	¥ 56
Asset Management One
Subsequent Event [Line Items]
Percentage of shareholding ratio based on voting rights	51.00%
Percentage of shareholding ratio based on economic interests	70.00%

Subsequent Events (Summary of C

Subsequent Events (Summary of Consideration Paid for DIAM) (Detail) - Subsequent Event - DIAM ¥ in Billions	Oct. 01, 2016JPY (¥)
Consideration
Equity instruments (1,038,408 common shares of MHAM)	¥ 29
Fair value of total consideration transferred	29
Fair value of MHFG's equity interests in DIAM held before the business combination	72
Business Combination, Consideration Transferred, Including Equity Interest in Acquiree Held Prior to Combination, Total	¥ 101

Subsequent Events (Summary o115

Subsequent Events (Summary of Consideration Paid for DIAM) (Parenthetical) (Detail)	Oct. 01, 2016shares
DIAM | Subsequent Event
Subsequent Event [Line Items]
Common shares of MHAM	1,038,408