Federal National Mortgage Association (FNMA) 10-Q 3 Aug 17 2017 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information	6 Months Ended
	Jun. 30, 2017shares
Entity [Abstract]
Entity Registrant Name	FEDERAL NATIONAL MORTGAGE ASSOCIATION FANNIE MAE
Entity Central Index Key	310,522
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Jun. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding	1,158,087,567

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Assets:
Cash and cash equivalents	$ 16,904	$ 25,224
Restricted cash (includes $26,279 and $31,536, related to consolidated trusts)	30,999	36,953
Federal funds sold and securities purchased under agreements to resell or similar arrangements	29,220	30,415
Investments in securities:
Trading, at fair value (includes $1,007 and $1,277, respectively, pledged as collateral )	39,274	40,562
Available-for-sale, at fair value (includes $98 and $107, respectively, related to consolidated trusts)	6,408	8,363
Total investments in securities	45,682	48,925
Mortgage loans:
Loans held for sale, at lower of cost or fair value	5,322	2,899
Loans held for investment, at amortized cost	3,140,492	3,100,319
Allowance for loan losses	(20,399)	(23,465)
Total loans held for investment, net of allowance	3,120,093	3,076,854
Total mortgage loans	3,125,415	3,079,753
Deferred tax assets, net	31,402	33,530
Accrued interest receivable (includes $7,223 and $7,064, respectively, related to consolidated trusts)	7,840	7,737
Acquired property, net	3,696	4,489
Other assets	18,072	20,942
Total assets	3,309,230	3,287,968
Liabilities:
Accrued interest payable (includes $8,389 and $8,285, respectively, related to consolidated trusts)	9,473	9,431
Other liabilities (includes $340 and $390, respectively, related to consolidated trusts)	8,373	10,150
Total liabilities	3,305,513	3,281,897
Commitments and contingencies (Note 15)	0	0
Stockholders’ equity:
Senior preferred stock, 1,000,000 shares issued and outstanding	117,149	117,149
Preferred stock, 700,000,000 shares are authorized—555,374,922 shares issued and outstanding	19,130	19,130
Common stock, no par value, no maximum authorization—1,308,762,703 shares issued, 1,158,087,567 and 1,158,082,750 shares outstanding, respectively	687	687
Accumulated deficit	(126,531)	(124,253)
Accumulated other comprehensive income	682	759
Treasury stock, at cost, 150,675,136 and 150,679,953 shares, respectively	(7,400)	(7,401)
Total stockholders’ equity (See Note 1: Senior Preferred Stock for information on our dividend to Treasury)	3,717	6,071
Total liabilities and equity	3,309,230	3,287,968
Fannie Mae [Member]
Mortgage loans:
Loans held for investment, at amortized cost	180,318	204,318
Liabilities:
Debt (includes $9,162 and $9,582, respectively, of debt of Fannie Mae at fair value and $36,372 and $36,524, respectively, of debt of consolidated trusts, at fair value)	303,120	327,097
Consolidated Trusts [Member]
Assets:
Restricted cash (includes $26,279 and $31,536, related to consolidated trusts)	26,279	31,536
Investments in securities:
Available-for-sale, at fair value (includes $98 and $107, respectively, related to consolidated trusts)	98	107
Mortgage loans:
Loans held for investment, at amortized cost	2,960,174	2,896,001
Accrued interest receivable (includes $7,223 and $7,064, respectively, related to consolidated trusts)	7,223	7,064
Liabilities:
Accrued interest payable (includes $8,389 and $8,285, respectively, related to consolidated trusts)	8,389	8,285
Debt (includes $9,162 and $9,582, respectively, of debt of Fannie Mae at fair value and $36,372 and $36,524, respectively, of debt of consolidated trusts, at fair value)	2,984,547	2,935,219
Other liabilities (includes $340 and $390, respectively, related to consolidated trusts)	$ 340	$ 390

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Assets:
Restricted cash (includes $26,279 and $31,536, related to consolidated trusts)	$ 30,999	$ 36,953
Investments in securities:
Trading, at fair value (includes $1,007 and $1,277, respectively, pledged as collateral )	1,007	1,277
Available-for-sale, at fair value (includes $98 and $107, respectively, related to consolidated trusts)	6,408	8,363
Accrued interest receivable (includes $7,223 and $7,064, respectively, related to consolidated trusts)	7,840	7,737
Mortgage loans:
Total loans held for investment (includes $11,406 and $12,057, respectively, at fair value)	11,406	12,057
Liabilities:
Accrued interest payable (includes $8,389 and $8,285, respectively, related to consolidated trusts)	9,473	9,431
Other liabilities (includes $340 and $390, respectively, related to consolidated trusts)	$ 8,373	$ 10,150
Stockholders’ equity:
Senior preferred stock, 1,000,000 shares issued	1,000,000	1,000,000
Senior preferred stock, 1,000,000 shares outstanding	1,000,000	1,000,000
Preferred stock, 700,000,000 shares are authorized	700,000,000	700,000,000
Preferred stock, 555,374,922 shares issued	555,374,922	555,374,922
Preferred stock, 555,374,922 shares outstanding	555,374,922	555,374,922
Common stock, 1,308,762,703 shares issued	1,308,762,703	1,308,762,703
Common stock, 1,158,087,567 and 1,158,082,750 shares outstanding, respectively	1,158,087,567	1,158,082,750
Treasury stock, at cost, 150,675,136 shares	150,675,136	150,679,953
Consolidated Trusts [Member]
Assets:
Restricted cash (includes $26,279 and $31,536, related to consolidated trusts)	$ 26,279	$ 31,536
Investments in securities:
Available-for-sale, at fair value (includes $98 and $107, respectively, related to consolidated trusts)	98	107
Accrued interest receivable (includes $7,223 and $7,064, respectively, related to consolidated trusts)	7,223	7,064
Liabilities:
Accrued interest payable (includes $8,389 and $8,285, respectively, related to consolidated trusts)	8,389	8,285
Debt (includes $9,008 and $9,582, respectively, of debt of Fannie Mae at fair value and $34,866 and $36,524, respectively, of debt of consolidated trusts, at fair value)	34,866	36,524
Other liabilities (includes $340 and $390, respectively, related to consolidated trusts)	340	390
Fannie Mae [Member]
Liabilities:
Debt (includes $9,008 and $9,582, respectively, of debt of Fannie Mae at fair value and $34,866 and $36,524, respectively, of debt of consolidated trusts, at fair value)	$ 9,008	$ 9,582

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Interest income:
Trading securities	$ 176	$ 128	$ 318	$ 248
Available-for-sale securities	91	170	192	373
Mortgage loans (includes $25,033 and $23,866, respectively, for the three months ended and $49,987 and $48,492, respectively, for the six months ended related to consolidated trusts)	27,011	26,256	54,058	53,217
Other	115	46	209	94
Total interest income	27,393	26,600	54,777	53,932
Interest expense:
Short-term debt	57	57	101	108
Long-term debt (includes $20,705 and $19,521, respectively, for the three months ended and $41,013 and $40,179, respectively, for the six months ended related to consolidated trusts)	22,334	21,257	44,328	43,769
Total interest expense	22,391	21,314	44,429	43,877
Net interest income	5,002	5,286	10,348	10,055
Benefit for credit losses	1,267	1,601	1,663	2,785
Net interest income after benefit for credit losses	6,269	6,887	12,011	12,840
Non-interest income (loss):
Investment gains, net	385	398	376	467
Fair value losses, net	(691)	(1,667)	(731)	(4,480)
Fee and other income	353	174	602	377
Non-interest income (loss)	47	(1,095)	247	(3,636)
Administrative expenses:
Salaries and employee benefits	332	331	676	695
Professional services	234	232	463	447
Occupancy expenses	47	46	93	91
Other administrative expenses	73	69	138	133
Total administrative expenses	686	678	1,370	1,366
Foreclosed property expense	34	63	251	397
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees	518	453	1,021	893
Other expenses, net	291	254	673	518
Total expenses	1,529	1,448	3,315	3,174
Income before federal income taxes	4,787	4,344	8,943	6,030
Provision for federal income taxes	(1,587)	(1,398)	(2,970)	(1,948)
Net income	3,200	2,946	5,973	4,082
Other comprehensive loss:
Changes in unrealized gains on available-for-sale securities, net of reclassification adjustments and taxes	(81)	(75)	(73)	(273)
Other	(2)	(2)	(4)	(4)
Total other comprehensive loss	(83)	(77)	(77)	(277)
Total comprehensive income	3,117	2,869	5,896	3,805
Net income	3,200	2,946	5,973	4,082
Dividends distributed or available for distribution to senior preferred stockholder (Note 9)	(3,117)	(2,869)	(5,896)	(3,788)
Net income attributable to common stockholders (Note 9)	$ 83	$ 77	$ 77	$ 294
Earnings per share, Basic	$ 0.01	$ 0.01	$ 0.01	$ 0.05
Earnings per share, Diluted	$ 0.01	$ 0.01	$ 0.01	$ 0.05
Weighted-average common shares outstanding, Basic	5,762	5,762	5,762	5,762
Weighted-average common shares outstanding, Diluted	5,893	5,893	5,893	5,893

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Mortgage loans (includes $25,033 and $23,866, respectively, for the three months ended and $49,987 and $48,492, respectively, for the six months ended related to consolidated trusts)	$ 27,011	$ 26,256	$ 54,058	$ 53,217
Long-term debt (includes $20,705 and $19,521, respectively, for the three months ended and $41,013 and $40,179, respectively, for the six months ended related to consolidated trusts)	22,334	21,257	44,328	43,769
Consolidated Trusts [Member]
Mortgage loans (includes $25,033 and $23,866, respectively, for the three months ended and $49,987 and $48,492, respectively, for the six months ended related to consolidated trusts)	25,033	23,866	49,987	48,492
Long-term debt (includes $20,705 and $19,521, respectively, for the three months ended and $41,013 and $40,179, respectively, for the six months ended related to consolidated trusts)	$ 20,705	$ 19,521	$ 41,013	$ 40,179

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Net cash provided by (used in) operating activities
Net cash provided by (used in) operating activities	$ 262	$ (3,982)
Cash flows provided by investing activities:
Proceeds from maturities and paydowns of trading securities held for investment	937	1,109
Proceeds from sales of trading securities held for investment	124	1,313
Proceeds from maturities and paydowns of available-for-sale securities	1,214	1,778
Proceeds from sales of available-for-sale securities	922	7,584
Purchases of loans held for investment	(90,180)	(97,024)
Net change in restricted cash	5,954	(6,818)
Advances to lenders	(57,533)	(57,956)
Proceeds from disposition of acquired property and preforeclosure sales	6,874	8,557
Net change in federal funds sold and securities purchased under agreements to resell or similar arrangements	1,195	5,025
Other, net	(208)	(661)
Net cash provided by investing activities	93,071	114,863
Cash flows used in financing activities:
Payments of cash dividends on senior preferred stock to Treasury	(8,250)	(3,778)
Other, net	11	30
Net cash used in financing activities	(101,653)	(101,936)
Net increase (decrease) in cash and cash equivalents	(8,320)	8,945
Cash and cash equivalents at beginning of period	25,224	14,674
Cash and cash equivalents at end of period	16,904	23,619
Cash paid during the period for:
Interest	56,207	52,354
Income taxes	1,070	610
Fannie Mae [Member]
Cash flows provided by investing activities:
Proceeds from repayments of loans acquired as held for investment	12,835	11,804
Proceeds from sales of loans acquired as held for investment of Fannie Mae	2,361	1,964
Cash flows used in financing activities:
Proceeds from issuance of debt	489,301	432,025
Payments to redeem debt	(514,228)	(456,586)
Consolidated Trusts [Member]
Cash flows provided by investing activities:
Proceeds from repayments of loans acquired as held for investment	208,576	238,188
Cash flows used in financing activities:
Proceeds from issuance of debt	181,764	171,004
Payments to redeem debt	$ (250,251)	$ (244,631)

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Organization We are a stockholder-owned corporation organized and existing under the Federal National Mortgage Association Charter Act (the “Charter Act” or our “charter”). We are a government-sponsored enterprise (“GSE”) and we are subject to government oversight and regulation. Our regulators include the Federal Housing Finance Agency (“FHFA”), the U.S. Department of Housing and Urban Development (“HUD”), the U.S. Securities and Exchange Commission (“SEC”), and the U.S. Department of the Treasury (“Treasury”). The U.S. government does not guarantee our securities or other obligations. Conservatorship On September 7, 2008, the Secretary of the Treasury and the Director of FHFA announced several actions taken by Treasury and FHFA regarding Fannie Mae, which included: (1) placing us in conservatorship, and (2) the execution of a senior preferred stock purchase agreement by our conservator, on our behalf, and Treasury, pursuant to which we issued to Treasury both senior preferred stock and a warrant to purchase common stock. Under the Federal Housing Enterprises Financial Safety and Soundness Act of 1992, as amended by the Federal Housing Finance Regulatory Reform Act of 2008 (together, the “GSE Act”), the conservator immediately succeeded to (1) all rights, titles, powers and privileges of Fannie Mae, and of any stockholder, officer or director of Fannie Mae with respect to Fannie Mae and its assets, and (2) title to the books, records and assets of any other legal custodian of Fannie Mae. The conservator has since delegated specified authorities to our Board of Directors and has delegated to management the authority to conduct our day-to-day operations. The conservator retains the authority to withdraw its delegations at any time. The conservatorship has no specified termination date and there continues to be significant uncertainty regarding our future, including how long we will continue to exist in our current form, the extent of our role in the market, how long we will be in conservatorship, what form we will have and what ownership interest, if any, our current common and preferred stockholders will hold in us after the conservatorship is terminated, and whether we will continue to exist following conservatorship. Under the GSE Act, FHFA must place us into receivership if the Director of FHFA makes a written determination that our assets are less than our obligations or if we have not been paying our debts, in either case, for a period of 60 days. In addition, the Director of FHFA may place us into receivership at his discretion at any time for other reasons set forth in the GSE Act, including if we are critically undercapitalized or if we are undercapitalized and have no reasonable prospect of becoming adequately capitalized. Should we be placed into receivership, different assumptions would be required to determine the carrying value of our assets, which could lead to substantially different financial results. We are not aware of any plans of FHFA to fundamentally change our business model or capital structure in the near term. Impact of U.S. Government Support We continue to rely on support from Treasury to eliminate any net worth deficits we may experience in the future, which would otherwise trigger our being placed into receivership. Based on consideration of all the relevant conditions and events affecting our operations, including our reliance on the U.S. government, we continue to operate as a going concern and in accordance with our delegation of authority from FHFA. We fund our business primarily through the issuance of short-term and long-term debt securities in the domestic and international capital markets. Because debt issuance is our primary funding source, we are subject to “roll over,” or refinancing, risk on our outstanding debt. Our ability to issue long-term debt has been strong primarily due to actions taken by the federal government to support us. We believe that continued federal government support of our business, as well as our status as a GSE, are essential to maintaining our access to debt funding. Changes or perceived changes in federal government support of our business without appropriate capitalization of the company could materially and adversely affect our liquidity, financial condition and results of operations. Changes or perceived changes in our status as a GSE could also materially and adversely affect our liquidity, financial condition and results of operations. In addition, due to our reliance on the U.S. government’s support, our access to debt funding or the cost of debt funding also could be materially adversely affected by a change or perceived change in the creditworthiness of the U.S. government. A downgrade in our credit ratings could reduce demand for our debt securities and increase our borrowing costs. Future changes or disruptions in the financial markets could significantly change the amount, mix and cost of funds we obtain, which also could increase our liquidity and “roll over” risk and have a material adverse impact on our liquidity, financial condition and results of operations. Pursuant to the senior preferred stock purchase agreement, Treasury has committed to provide us with funding to help us maintain a positive net worth thereby avoiding the mandatory receivership trigger described above. As consideration for Treasury’s funding commitment, we issued one million shares of senior preferred stock and a warrant to purchase shares of our common stock to Treasury. As of June 30, 2017 , the amount of remaining funding available to us under the senior preferred stock purchase agreement was $117.6 billion . Senior Preferred Stock Treasury, as the holder of the senior preferred stock, is entitled to receive quarterly cash dividends, when, as and if declared by our conservator, acting as successor to the rights, titles, powers and privileges of the Board of Directors. The dividends we have paid to Treasury on the senior preferred stock during conservatorship have been declared by, and paid at the direction of, our conservator. For each quarterly period through and including December 31, 2017, dividends on the senior preferred stock accumulate based on the amount by which our net worth at the end of the immediately preceding fiscal quarter exceeds an applicable capital reserve amount. If our net worth does not exceed the applicable capital reserve amount, then dividends will neither accumulate nor be payable to the shareholder for such period. Pursuant to the terms of our senior preferred stock, our net worth is the amount by which our total assets (excluding Treasury’s funding commitment and any unfunded amounts related to the commitment) exceed our total liabilities (excluding any obligation in respect of capital stock), in each case as reflected on our balance sheet prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). The applicable capital reserve amount was $1.2 billion for 2016, decreased to $600 million for quarterly dividend periods in 2017, and will decrease to zero in 2018. We recognize a liability on our balance sheet for senior preferred stock dividends only upon their declaration by our conservator, at which point they become payable to the shareholder. Shares of the senior preferred stock have no par value and have a stated value and initial liquidation preference equal to $1,000 per share. The liquidation preference of the senior preferred stock is subject to adjustment. To the extent that quarterly dividends are not paid, they will accumulate and be added to the liquidation preference of the senior preferred stock. In addition, the liquidation preference of the senior preferred stock will be increased by (1) any amounts Treasury pays to us pursuant to its funding commitment provided in the senior preferred stock purchase agreement and (2) any quarterly commitment fee payments that are payable but not paid in cash or waived by Treasury under the senior preferred stock purchase agreement. As long as the dividend provisions described above remain in effect, however, the periodic commitment fee will neither accrue nor become payable. As of June 30, 2017 , we have received a total of $116.1 billion under Treasury’s funding commitment and the aggregate liquidation preference of the senior preferred stock was $117.1 billion . Because the senior preferred stock ranks prior to our common stock and all other series of our preferred stock, as well as any capital stock we issue in the future, as to both dividends and distributions upon liquidation, if we are liquidated, the senior preferred stock is entitled to its then-current liquidation preference (which includes any accumulated but unpaid dividends) before any distribution is made to the holders of our common stock or other preferred stock. On June 30, 2017 , we paid Treasury a dividend of $2.8 billion based on our net worth of $3.4 billion as of March 31, 2017 , less the applicable capital reserve amount of $600 million . We will pay Treasury a dividend of $3.1 billion by September 30, 2017 , calculated based on our net worth of $3.7 billion as of June 30, 2017 , less the applicable capital reserve amount of $600 million , if our conservator declares a dividend in this amount before September 30, 2017 . Basis of Presentation The accompanying unaudited interim condensed consolidated financial statements have been prepared in accordance with GAAP for interim financial information and with the SEC’s instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and note disclosures required by GAAP for complete consolidated financial statements. In the opinion of management, all adjustments of a normal recurring nature considered necessary for a fair presentation have been included. The accompanying condensed consolidated financial statements include our accounts as well as the accounts of other entities in which we have a controlling financial interest. All intercompany accounts and transactions have been eliminated. To conform to our current period presentation, we have reclassified certain amounts reported in our prior periods’ condensed consolidated financial statements. Results for the six months ended June 30, 2017 may not necessarily be indicative of the results for the year ending December 31, 2017 . The unaudited interim condensed consolidated financial statements as of and for the six months ended June 30, 2017 should be read in conjunction with our audited consolidated financial statements and related notes included in our annual report on Form 10-K for the year ended December 31, 2016 (“ 2016 Form 10-K”), filed with the SEC on February 17, 2017 . Regulatory Capital FHFA stated that, during conservatorship, our existing statutory and FHFA-directed regulatory capital requirements will not be binding and FHFA will not issue quarterly capital classifications. We submit capital reports to FHFA and FHFA monitors our capital levels. The deficit of core capital over statutory minimum capital was $137.9 billion as of June 30, 2017 and $136.2 billion as of December 31, 2016 . Under the terms of the senior preferred stock, we are required to pay Treasury a dividend each quarter, when, as and if declared, equal to the excess of our net worth as of the end of the preceding quarter over an applicable capital reserve amount. The Director of FHFA has directed us to make dividend payments on the senior preferred stock on a quarterly basis. Therefore, we do not expect to eliminate our deficit of core capital over statutory minimum capital. Related Parties As a result of our issuance to Treasury of the warrant to purchase shares of Fannie Mae common stock equal to 79.9% of the total number of shares of Fannie Mae common stock, we and Treasury are deemed related parties. As of June 30, 2017 , Treasury held an investment in our senior preferred stock with an aggregate liquidation preference of $117.1 billion . FHFA’s control of both us and Freddie Mac has caused us, FHFA and Freddie Mac to be deemed related parties. In 2013, Fannie Mae and Freddie Mac established Common Securitization Solutions, LLC (“CSS”), a jointly owned limited liability company to operate a common securitization platform; therefore, CSS is deemed a related party. Transactions with Treasury Our administrative expenses were reduced by $ 11 million and $ 23 million for the three and six months ended June 30, 2017 , respectively, and $15 million and $31 million for the three and six months ended June 30, 2016 , respectively, due to reimbursements from Treasury and Freddie Mac for expenses incurred as program administrator for Treasury’s Home Affordable Modification Program (“HAMP”) and other initiatives under Treasury’s Making Home Affordable Program. We made tax payments to the Internal Revenue Service (“IRS”), a bureau of Treasury, of $1.1 billion during the three and six months ended June 30, 2017. We made tax payments of $250 million and $610 million during the three and six months ended June 30, 2016 , respectively. In 2009, we entered into a memorandum of understanding with Treasury, FHFA and Freddie Mac pursuant to which we agreed to provide assistance to state and local housing finance agencies (“HFAs”) through certain programs, including a new issue bond (“NIB”) program. As of June 30, 2017 , under the NIB program, Fannie Mae and Freddie Mac had $5.2 billion outstanding of pass-through securities backed by single-family and multifamily housing bonds issued by HFAs, which is less than 35% of the total original principal under the program, the amount of losses that Treasury would bear. Accordingly, we do not have a potential risk of loss under the NIB program. The fee revenue and expense related to the Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) are recorded in “Mortgage loans interest income” and “TCCA fees,” respectively, in our condensed consolidated statements of operations and comprehensive income. We recognized $518 million and $453 million in TCCA fees during the three months ended June 30, 2017 and 2016 , respectively, and $1.0 billion and $893 million for the six months ended June 30, 2017 and 2016 , respectively, of which $518 million had not been remitted to Treasury as of June 30, 2017 . We incurred expenses in connection with certain funding obligations under the GSE Act, a portion of which is attributable to Treasury’s Capital Magnet and HOPE Reserve Funds. These expenses, recognized in “Other expenses, net” in our condensed consolidated statements of operations and comprehensive income, were measured as the product of 4.2 basis points and the unpaid principal balance of our total new business purchases for the respective period. We recognized $ 29 million and $ 31 million in “Other expenses, net” in connection with Treasury’s Capital Magnet and HOPE Reserve Funds for the three months ended June 30, 2017 and 2016 , respectively, and $58 million and $56 million for the six months ended June 30, 2017 and 2016 , respectively, of which $58 million had not been remitted as of June 30, 2017 . In addition to the transactions with Treasury mentioned above, we also purchase and sell Treasury securities in the normal course of business. As of June 30, 2017 and December 31, 2016 , we held Treasury securities with a fair value of $32.4 billion and $32.3 billion , respectively, and accrued interest receivable of $63 million and $39 million , respectively. We recognized interest income on these securities held by us of $86 million and $33 million for the three months ended June 30, 2017 and 2016 , respectively, and $149 million and $65 million for the six months ended June 30, 2017 and 2016 , respectively. Transactions with Freddie Mac As of June 30, 2017 and December 31, 2016 , we held Freddie Mac mortgage-related securities with a fair value of $748 million and $1.4 billion , respectively, and accrued interest receivable of $3 million and $5 million , respectively. We recognized interest income on these securities held by us of $ 10 million and $ 36 million for the three months ended June 30, 2017 and 2016 , respectively, and $23 million and $81 million for the six months ended June 30, 2017 and 2016 , respectively. In addition, Freddie Mac may be an investor in variable interest entities (“VIEs”) that we have consolidated, and we may be an investor in VIEs that Freddie Mac has consolidated. Freddie Mac may also be an investor in our debt securities. Transactions with FHFA The GSE Act authorizes FHFA to establish an annual assessment for regulated entities, including Fannie Mae, which is payable on a semi-annual basis (April and October), for FHFA’s costs and expenses, as well as to maintain FHFA’s working capital. We recognized FHFA assessment fees, which are recorded in “Administrative expenses” in our condensed consolidated statements of operations and comprehensive income, of $26 million and $28 million for the three months ended June 30, 2017 and 2016 , respectively, and $ 56 million for the six months ended June 30, 2017 and 2016 . Transactions with CSS In connection with our jointly owned company with Freddie Mac, we contributed capital to CSS of $ 18 million and $ 35 million for the three months ended June 30, 2017 and 2016 , respectively, and $53 million and $65 million for the six months ended June 30, 2017 and 2016 , respectively. In November 2016, Fannie Mae, Freddie Mac and CSS entered into a Customer Services Agreement that sets forth the terms under which CSS will provide securitization services to us and Freddie Mac. No other transactions outside of normal business activities have occurred between us and CSS during the six months ended June 30, 2017 and 2016 . Use of Estimates Preparing condensed consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that affect our reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities as of the dates of our condensed consolidated financial statements, as well as our reported amounts of revenues and expenses during the reporting periods. Management has made significant estimates in a variety of areas including, but not limited to, valuation of certain financial instruments, other assets and liabilities, and allowance for loan losses. Actual results could be different from these estimates. New Accounting Guidance In June 2016, the Financial Accounting Standards Board (“FASB”) issued guidance that changes the impairment model for most financial assets and certain other instruments. For loans, held-to-maturity debt securities and other financial assets recorded at amortized cost, entities will be required to use a new forward-looking “expected loss” model that will replace today’s “incurred loss” model and generally will result in the earlier recognition of allowance for loan losses. The guidance is effective on January 1, 2020 with early adoption permitted on January 1, 2019. We will recognize the impact of the new guidance through a cumulative effect adjustment to retained earnings as of the beginning of the year of adoption. We are continuing to evaluate the impact of this guidance on our condensed consolidated financial statements, including the timing of the adoption. We expect the greater impact of the guidance to relate to our accounting for credit losses for loans that are not individually impaired. The adoption of this guidance will decrease, perhaps substantially, our retained earnings and increase our allowance for loan losses.

Consolidations and Transfers of

Consolidations and Transfers of Financial Assets	6 Months Ended
	Jun. 30, 2017
Consolidations and Transfers of Financial Assets [Abstract]
Consolidations and Transfers of Financial Assets	Consolidations and Transfers of Financial Assets We have interests in various entities that are considered to be VIEs. The primary types of entities are securitization trusts and limited partnerships. These interests include investments in securities issued by VIEs, such as Fannie Mae MBS created pursuant to our securitization transactions and our guaranty to the entity. We consolidate the substantial majority of our single-class securitization trusts because our role as guarantor and master servicer provides us with the power to direct matters (primarily the servicing of mortgage loans) that impact the credit risk to which we are exposed. In contrast, we do not consolidate single-class securitization trusts when other organizations have the power to direct these activities. Unconsolidated VIEs We do not consolidate VIEs when we are not deemed to be the primary beneficiary. Our unconsolidated VIEs include securitization trusts and limited partnerships. The following table displays the carrying amount and classification of our assets and liabilities that relate to our involvement with unconsolidated securitization trusts. As of June 30, 2017 December 31, 2016 (Dollars in millions) Assets: Trading securities: Fannie Mae $ 4,197 $ 4,642 Non-Fannie Mae 2,577 3,473 Total trading securities 6,774 8,115 Available-for-sale securities: Fannie Mae 2,174 2,447 Non-Fannie Mae 3,319 4,879 Total available-for-sale securities 5,493 7,326 Other assets 74 77 Other liabilities (501 ) (528 ) Net carrying amount $ 11,840 $ 14,990 Our maximum exposure to loss generally represents the greater of our recorded investment in the entity or the unpaid principal balance of the assets covered by our guaranty. However, our securities issued by Fannie Mae multi-class resecuritization trusts that are not consolidated do not give rise to any additional exposure to loss as we already consolidate the underlying collateral. The maximum exposure to loss related to unconsolidated securitization trusts was approximately $17 billion and $21 billion as of June 30, 2017 and December 31, 2016 , respectively. The total assets of our unconsolidated securitization trusts were approximately $100 billion and $150 billion as of June 30, 2017 and December 31, 2016 , respectively. The maximum exposure to loss for our unconsolidated limited partnerships and similar legal entities, which consist of low-income housing tax credit investments, community investments and other entities, was $108 million and the related carrying value was $83 million as of June 30, 2017 . As of December 31, 2016 , the maximum exposure to loss was $118 million and the related carrying value was $92 million . The total assets of these limited partnership investments were $3.6 billion and $3.9 billion as of June 30, 2017 and December 31, 2016 , respectively. The unpaid principal balance of our multifamily loan portfolio was $244.7 billion as of June 30, 2017 . As our lending relationship does not provide us with a controlling financial interest in the borrower entity, we do not consolidate these borrowers regardless of their status as either a VIE or a voting interest entity. We have excluded these entities from our VIE disclosures. However, the disclosures we have provided in “ Note 3, Mortgage Loans ,” “ Note 4, Allowance for Loan Losses ” and “ Note 6, Financial Guarantees ” with respect to this population are consistent with the FASB’s stated objectives for the disclosures related to unconsolidated VIEs. Transfers of Financial Assets We issue Fannie Mae MBS through portfolio securitization transactions by transferring pools of mortgage loans or mortgage-related securities to one or more trusts or special purpose entities. We are considered to be the transferor when we transfer assets from our own retained mortgage portfolio in a portfolio securitization transaction. For the three months ended June 30, 2017 and 2016 , the unpaid principal balance of portfolio securitizations was $69.2 billion and $64.3 billion , respectively. For the six months ended June 30, 2017 and 2016 , the unpaid principal balance of portfolio securitizations was $126.5 billion and $112.6 billion , respectively. We retain interests from the transfer and sale of mortgage-related securities to unconsolidated single-class and multi-class portfolio securitization trusts. As of June 30, 2017 , the unpaid principal balance of retained interests was $4.1 billion and its related fair value was $5.2 billion . The unpaid principal balance of retained interests was $4.4 billion and its related fair value was $5.8 billion as of December 31, 2016 . For the three months ended June 30, 2017 and 2016 , the principal and interest received on retained interests was $303 million and $315 million , respectively. For the six months ended June 30, 2017 and 2016 , the principal and interest received on retained interests was $560 million and $623 million , respectively. Managed Loans Managed loans are on-balance sheet mortgage loans, as well as mortgage loans that we have securitized in unconsolidated portfolio securitization trusts. The unpaid principal balance of securitized loans in unconsolidated portfolio securitization trusts, which are primarily loans that are guaranteed or insured, in whole or in part, by the U.S. government, was $1.3 billion and $1.4 billion as of June 30, 2017 and December 31, 2016 , respectively. For information on our on-balance sheet mortgage loans, see “ Note 3, Mortgage Loans .”

Mortgage Loans

Mortgage Loans	6 Months Ended
	Jun. 30, 2017
Mortgage Loans on Real Estate [Abstract]
Mortgage Loans	Mortgage Loans We own single-family mortgage loans, which are secured by four or fewer residential dwelling units, and multifamily mortgage loans, which are secured by five or more residential dwelling units. We classify these loans as either held for investment (“HFI”) or held for sale (“HFS”). We report the carrying value of HFI loans at the unpaid principal balance, net of unamortized premiums and discounts, other cost basis adjustments, and an allowance for loan losses. We report the carrying value of HFS loans at the lower of cost or fair value and record valuation changes in “Investment gains, net” in our condensed consolidated statements of operations and comprehensive income. We define the recorded investment of HFI loans as unpaid principal balance, net of unamortized premiums and discounts, other cost basis adjustments, and accrued interest receivable. For purposes of the single-family mortgage loan disclosures below, we define “primary” class as mortgage loans that are not included in other loan classes; “government” class as mortgage loans that are guaranteed or insured, in whole or in part, by the U.S. government or one of its agencies, and that are not Alt-A; and “other” class as loans with higher-risk characteristics, such as interest-only loans and negative-amortizing loans, that are neither government nor Alt-A. The following table displays the carrying value of our mortgage loans. As of June 30, 2017 December 31, 2016 (Dollars in millions) Single-family $ 2,861,253 $ 2,833,750 Multifamily 244,701 229,896 Total unpaid principal balance of mortgage loans 3,105,954 3,063,646 Cost basis and fair value adjustments, net 39,860 39,572 Allowance for loan losses for loans held for investment (20,399 ) (23,465 ) Total mortgage loans $ 3,125,415 $ 3,079,753 During the three and six months ended June 30, 2017 , we redesignated loans with a carrying value of $ 2.9 billion and $5.4 billion , respectively, from HFI to HFS. During the three and six months ended June 30, 2016 , we redesignated loans with a carrying value of $ 1.0 billion and $1.6 billion , respectively, from HFI to HFS. During the three and six months ended June 30, 2017 , we redesignated loans with a carrying value of $ 17 million and $52 million , respectively, from HFS to HFI. We sold loans with an unpaid principal balance of $2.9 billion and $ 3.0 billion during the three and six months ended June 30, 2017 , respectively. We sold loans with an unpaid balance of $ 1.5 billion and $2.6 billion during the three and six months ended June 30, 2016 , respectively. The recorded investment of single-family mortgage loans for which formal foreclosure proceedings are in process was $15.6 billion and $18.3 billion as of June 30, 2017 and December 31, 2016 , respectively. As a result of our various loss mitigation and foreclosure prevention efforts, we expect that a portion of the loans in the process of formal foreclosure proceedings will not ultimately foreclose. Nonaccrual Loans We discontinue accruing interest on loans when we believe collectibility of principal or interest is not reasonably assured, which for a single-family loan we have determined, based on our historical experience, to be when the loan becomes two months or more past due according to its contractual terms. Interest previously accrued but not collected is reversed through interest income at the date a loan is placed on nonaccrual status. We return a nonmodified single-family loan to accrual status at the point that the borrower brings the loan current. We return a modified single-family loan to accrual status at the point that the borrower successfully makes all required payments during the trial period (generally three to four months) and the modification is made permanent. We place a multifamily loan on nonaccrual status when the loan becomes three months or more past due according to its contractual terms or is deemed to be individually impaired, unless the loan is well secured such that collectibility of principal and accrued interest is reasonably assured. We return a multifamily loan to accrual status when the borrower cures the delinquency of the loan or we otherwise determine that the loan is well secured such that collectibility is reasonably assured. Aging Analysis The following tables display an aging analysis of the total recorded investment in our HFI mortgage loans by portfolio segment and class, excluding loans for which we have elected the fair value option. As of June 30, 2017 30 - 59 Days Delinquent 60 - 89 Days Delinquent Seriously Delinquent (1) Total Delinquent Current Total Recorded Investment in Loans 90 Days or More Delinquent and Accruing Interest Recorded Investment in Nonaccrual Loans (Dollars in millions) Single-family: Primary $ 27,294 $ 6,677 $ 17,842 $ 51,813 $ 2,703,162 $ 2,754,975 $ 19 $ 28,056 Government (2) 50 21 229 300 35,080 35,380 228 1 Alt-A 3,103 1,000 3,451 7,554 66,845 74,399 2 5,026 Other 1,141 367 1,259 2,767 22,580 25,347 4 1,827 Total single-family 31,588 8,065 22,781 62,434 2,827,667 2,890,101 253 34,910 Multifamily (3) 27 N/A 95 122 246,506 246,628 — 341 Total $ 31,615 $ 8,065 $ 22,876 $ 62,556 $ 3,074,173 $ 3,136,729 $ 253 $ 35,251 As of December 31, 2016 30 - 59 Days Delinquent 60 - 89 Days Delinquent Seriously Delinquent (1) Total Delinquent Current Total Recorded Investment in Loans 90 Days or More Delinquent and Accruing Interest Recorded Investment in Nonaccrual Loans (Dollars in millions) Single-family: Primary $ 31,631 $ 7,910 $ 21,761 $ 61,302 $ 2,654,195 $ 2,715,497 $ 22 $ 33,448 Government (2) 56 22 256 334 36,814 37,148 256 — Alt-A 3,629 1,194 4,221 9,044 72,903 81,947 2 6,019 Other 1,349 438 1,582 3,369 25,974 29,343 5 2,238 Total single-family 36,665 9,564 27,820 74,049 2,789,886 2,863,935 285 41,705 Multifamily (3) 44 N/A 129 173 231,708 231,881 — 403 Total $ 36,709 $ 9,564 $ 27,949 $ 74,222 $ 3,021,594 $ 3,095,816 $ 285 $ 42,108 __________ (1) Single-family seriously delinquent loans are loans that are 90 days or more past due or in the foreclosure process. Multifamily seriously delinquent loans are loans that are 60 days or more past due. (2) Primarily consists of reverse mortgages, which due to their nature, are not aged and are included in the current column. (3) Multifamily loans 60 - 89 days delinquent are included in the seriously delinquent column. Credit Quality Indicators The following table displays the total recorded investment in our single-family HFI loans by class and credit quality indicator, excluding loans for which we have elected the fair value option. As of June 30, 2017 (1) December 31, 2016 (1) Primary Alt-A Other Primary Alt-A Other (Dollars in millions) Estimated mark-to-market loan-to-value (“LTV”) ratio: (2) Less than or equal to 80% $ 2,410,185 $ 54,917 $ 18,219 $ 2,321,201 $ 56,250 $ 19,382 Greater than 80% and less than or equal to 90% 231,412 8,010 2,826 244,231 9,787 3,657 Greater than 90% and less than or equal to 100% 88,637 5,088 1,908 114,412 6,731 2,627 Greater than 100% 24,741 6,384 2,394 35,653 9,179 3,677 Total $ 2,754,975 $ 74,399 $ 25,347 $ 2,715,497 $ 81,947 $ 29,343 __________ (1) Excludes $35.4 billion and $37.1 billion as of June 30, 2017 and December 31, 2016 , respectively, of mortgage loans guaranteed or insured, in whole or in part, by the U.S. government or one of its agencies, that are not Alt-A loans. The segment class is primarily reverse mortgages for which we do not calculate an estimated mark-to-market LTV ratio. (2) The aggregate estimated mark-to-market LTV ratio is based on the unpaid principal balance of the loan as of the end of each reported period divided by the estimated current value of the property, which we calculate using an internal valuation model that estimates periodic changes in home value. The following table displays the total recorded investment in our multifamily HFI loans by credit quality indicator, excluding loans for which we have elected the fair value option. As of June 30, December 31, 2017 2016 (Dollars in millions) Credit risk profile by internally assigned grade: Non-classified $ 243,555 $ 228,749 Classified: (1) Substandard 3,069 3,129 Doubtful 4 3 Total classified 3,073 3,132 Total $ 246,628 $ 231,881 _________ (1) A loan classified as “Substandard” has a well-defined weakness that jeopardizes the timely full repayment. “Doubtful” refers to a loan with a weakness that makes collection or liquidation in full highly questionable and improbable based on existing conditions and values. Individually Impaired Loans Individually impaired loans include troubled debt restructurings (“TDRs”), acquired credit-impaired loans and multifamily loans that we have assessed as probable that we will not collect all contractual amounts due, regardless of whether we are currently accruing interest; excluding loans classified as HFS. The following tables display the total unpaid principal balance, recorded investment, related allowance, average recorded investment and interest income recognized for individually impaired loans. As of June 30, 2017 December 31, 2016 Unpaid Principal Balance Total Recorded Investment Related Allowance for Loan Losses Unpaid Principal Balance Total Recorded Investment Related Allowance for Loan Losses (Dollars in millions) Individually impaired loans: With related allowance recorded: Single-family: Primary $ 97,394 $ 92,591 $ 12,778 $ 105,113 $ 99,825 $ 14,462 Government 288 291 58 302 305 59 Alt-A 25,862 23,556 4,642 28,599 26,059 5,365 Other 9,651 9,106 1,719 11,087 10,465 2,034 Total single-family 133,195 125,544 19,197 145,101 136,654 21,920 Multifamily 217 218 41 320 323 33 Total individually impaired loans with related allowance recorded 133,412 125,762 19,238 145,421 136,977 21,953 With no related allowance recorded: (1) Single-family: Primary 16,109 15,225 — 15,733 14,758 — Government 67 62 — 63 59 — Alt-A 3,418 3,010 — 3,511 3,062 — Other 1,078 992 — 1,159 1,065 — Total single-family 20,672 19,289 — 20,466 18,944 — Multifamily 268 269 — 266 266 — Total individually impaired loans with no related allowance recorded 20,940 19,558 — 20,732 19,210 — Total individually impaired loans (2) $ 154,352 $ 145,320 $ 19,238 $ 166,153 $ 156,187 $ 21,953 For the Three Months Ended June 30, 2017 2016 Average Recorded Investment Total Interest Income Recognized (3) Interest Income Recognized on a Cash Basis Average Recorded Investment Total Interest Income Recognized (3) Interest Income Recognized on a Cash Basis (Dollars in millions) Individually impaired loans: With related allowance recorded: Single-family: Primary $ 94,599 $ 955 $ 77 $ 106,674 $ 1,015 $ 71 Government 295 2 — 317 3 — Alt-A 24,249 240 14 27,901 256 11 Other 9,419 82 5 11,639 93 3 Total single-family 128,562 1,279 96 146,531 1,367 85 Multifamily 259 4 — 556 13 — Total individually impaired loans with related allowance recorded 128,821 1,283 96 147,087 1,380 85 With no related allowance recorded: (1) Single-family: Primary 15,091 273 24 15,377 327 30 Government 61 1 — 59 1 — Alt-A 3,026 67 2 3,361 81 5 Other 1,016 21 1 1,126 30 2 Total single-family 19,194 362 27 19,923 439 37 Multifamily 284 7 — 326 3 — Total individually impaired loans with no related allowance recorded 19,478 369 27 20,249 442 37 Total individually impaired loans $ 148,299 $ 1,652 $ 123 $ 167,336 $ 1,822 $ 122 For the Six Months Ended June 30, 2017 2016 Average Recorded Investment Total Interest Income Recognized (3) Interest Income Recognized on a Cash Basis Average Recorded Investment Total Interest Income Recognized (3) Interest Income Recognized on a Cash Basis (Dollars in millions) Individually impaired loans: With related allowance recorded: Single-family: Primary $ 96,395 $ 1,941 $ 165 $ 107,984 $ 2,036 $ 175 Government 298 5 — 320 6 — Alt-A 24,896 489 29 28,287 509 30 Other 9,805 169 10 11,827 185 11 Total single-family 131,394 2,604 204 148,418 2,736 216 Multifamily 280 6 — 589 18 — Total individually impaired loans with related allowance recorded 131,674 2,610 204 149,007 2,754 216 With no related allowance recorded: (1) Single-family: Primary 15,050 562 47 15,323 595 50 Government 61 2 — 58 2 — Alt-A 3,056 140 5 3,362 143 8 Other 1,041 44 2 1,131 52 3 Total single-family 19,208 748 54 19,874 792 61 Multifamily 278 10 — 335 6 — Total individually impaired loans with no related allowance recorded 19,486 758 54 20,209 798 61 Total individually impaired loans $ 151,160 $ 3,368 $ 258 $ 169,216 $ 3,552 $ 277 __________ (1) The discounted cash flows or collateral value equals or exceeds the carrying value of the loan and, as such, no valuation allowance is required. (2) Includes single-family loans restructured in a TDR with a recorded investment of $144.3 billion and $155.0 billion as of June 30, 2017 and December 31, 2016 , respectively. Includes multifamily loans restructured in a TDR with a recorded investment of $198 million and $248 million as of June 30, 2017 and December 31, 2016 , respectively. (3) Total single-family interest income recognized of $1.7 billion for the three months ended June 30, 2017 consists of $1.5 billion of contractual interest and $229 million of effective yield adjustments. Total single-family interest income recognized of $1.8 billion for the three months ended June 30, 2016 consists of $1.5 billion of contractual interest and $331 million of effective yield adjustments. Total single-family interest income recognized of $3.4 billion for the six months ended June 30, 2017 consists of $2.9 billion of contractual interest and $497 million of effective yield adjustments. Total single-family interest income recognized of $3.5 billion for the six months ended June 30, 2016 consists of $2.9 billion of contractual interest and $641 million of effective yield adjustments. Troubled Debt Restructurings A modification to the contractual terms of a loan that results in granting a concession to a borrower experiencing financial difficulties is considered a TDR. The substantial majority of the loan modifications we complete result in term extensions, interest rate reductions or a combination of both. During the three months ended June 30, 2017 and 2016 , the average term extension of a single-family modified loan was 155 months and 159 months , respectively, and the average interest rate reduction was 0.67 and 0.72 percentage points, respectively. During the six months ended June 30, 2017 and 2016 , the average term extension of a single-family modified loan was 154 months and 159 months , respectively, and the average interest rate reduction was 0.80 and 0.73 percentage points, respectively. The following tables display the number of loans and recorded investment in loans restructured in a TDR. For the Three Months Ended June 30, 2017 2016 Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 14,148 $ 1,945 14,814 $ 2,028 Government 45 4 28 3 Alt-A 1,328 194 1,623 238 Other 271 46 362 61 Total single-family 15,792 2,189 16,827 2,330 Multifamily 3 17 4 45 Total TDRs 15,795 $ 2,206 16,831 $ 2,375 For the Six Months Ended June 30, 2017 2016 Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 31,383 $ 4,308 32,004 $ 4,360 Government 106 10 82 9 Alt-A 2,893 418 3,534 508 Other 580 99 761 133 Total single-family 34,962 4,835 36,381 5,010 Multifamily 3 17 4 45 Total TDRs 34,965 $ 4,852 36,385 $ 5,055 The following tables display the number of loans and our recorded investment in these loans at the time of payment default for loans that were restructured in a TDR in the twelve months prior to the payment default. For purposes of this disclosure, we define loans that had a payment default as: single-family and multifamily loans with completed TDRs that liquidated during the period, either through foreclosure, deed-in-lieu of foreclosure, or a short sale; single-family loans with completed modifications that are two or more months delinquent during the period; or multifamily loans with completed modifications that are one or more months delinquent during the period. For the Three Months Ended June 30, 2017 2016 Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 4,238 $ 589 4,648 $ 638 Government 25 3 27 3 Alt-A 616 97 756 116 Other 150 30 289 40 Total TDRs that subsequently defaulted 5,029 $ 719 5,720 $ 797 For the Six Months Ended June 30, 2017 2016 Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 8,717 $ 1,210 10,109 $ 1,440 Government 44 5 42 5 Alt-A 1,230 193 1,608 260 Other 351 68 532 89 Total single-family 10,342 1,476 12,291 1,794 Multifamily 1 4 — — Total TDRs that subsequently defaulted 10,343 $ 1,480 12,291 $ 1,794

Allowance for Loan Losses

Allowance for Loan Losses	6 Months Ended
	Jun. 30, 2017
Receivables [Abstract]
Allowance for Loan Losses	Allowance for Loan Losses We maintain an allowance for loan losses for HFI loans held by Fannie Mae and loans backing Fannie Mae MBS issued from consolidated trusts. When calculating our allowance for loan losses, we consider our net carrying value of HFI loans at the balance sheet date, which includes unpaid principal balance, net of amortized premiums and discounts, and other cost basis adjustments. We record charge-offs as a reduction to our allowance for loan losses at the point of foreclosure, completion of a short sale, upon the redesignation of loans from HFI to HFS or when a loan is determined to be uncollectible. We aggregate single-family HFI loans that are not individually impaired based on similar risk characteristics for purposes of estimating incurred credit losses and establishing a collective single-family loss reserve using an econometric model that derives an overall loss reserve estimate. We base our allowance methodology on historical events and trends, such as loss severity (in event of default), default rates, and recoveries from mortgage insurance contracts and other credit enhancements that provide loan level loss coverage and are either contractually attached to a loan or that were entered into contemporaneously with and in contemplation of a guaranty or loan purchase transaction. We use recent regional historical sales and appraisal information including the sales of our own foreclosed properties, to develop our loss severity estimates for all loan categories. Our allowance calculation also incorporates a loss confirmation period (the anticipated time lag between a credit loss event and the confirmation of the credit loss resulting from that event) to ensure our allowance estimate captures credit losses that have been incurred as of the balance sheet date but have not been confirmed. In addition, management performs a review of the observable data used in its estimate to ensure it is representative of prevailing economic conditions and other events existing as of the balance sheet date. Individually impaired single-family loans currently include those restructured in a TDR and acquired credit-impaired loans. We consider a loan to be impaired when, based on current information, it is probable that we will not receive all amounts due, including interest, in accordance with the contractual terms of the loan agreement. When a loan has been restructured, we measure impairment using a cash flow analysis discounted at the loan’s original effective interest rate. If we expect to recover our recorded investment in an individually impaired loan through probable foreclosure of the underlying collateral, we measure impairment based on the fair value of the collateral, reduced by estimated disposal costs and adjusted for estimated proceeds from mortgage, flood, or hazard insurance or similar sources. We establish a collective allowance for all loans in our multifamily guaranty book of business that are not individually impaired using an internal model that applies loss factors to loans in similar risk categories. Our loss factors are developed based on our historical default and loss severity experience. We identify multifamily loans for evaluation for impairment through a credit risk assessment process. If we determine that a multifamily loan is individually impaired, we generally measure impairment on that loan based on the fair value of the underlying collateral less estimated costs to sell the property, as we have concluded that such loans are collateral dependent. We evaluate collectively for impairment smaller-balance homogeneous multifamily loans. The following table displays changes in single-family, multifamily and total allowance for loan losses. For the Three Months Ended June 30, For the Six Months Ended June 30, 2017 2016 2017 2016 (Dollars in millions) Single-family allowance for loan losses: Beginning balance $ 21,938 $ 25,597 $ 23,283 $ 27,709 Benefit for loan losses (1) (1,185 ) (1,332 ) (1,605 ) (2,348 ) Charge-offs (689 ) (818 ) (1,729 ) (2,097 ) Recoveries 146 115 231 234 Other (2) 8 22 38 86 Ending balance $ 20,218 $ 23,584 $ 20,218 $ 23,584 Multifamily allowance for loan losses: Beginning balance $ 191 $ 222 $ 182 $ 242 Benefit for loan losses (1) (11 ) (4 ) (2 ) (20 ) Charge-offs — (3 ) — (8 ) Recoveries 1 — 1 1 Ending balance $ 181 $ 215 $ 181 $ 215 Total allowance for loan losses: Beginning balance $ 22,129 $ 25,819 $ 23,465 $ 27,951 Benefit for loan losses (1) (1,196 ) (1,336 ) (1,607 ) (2,368 ) Charge-offs (689 ) (821 ) (1,729 ) (2,105 ) Recoveries 147 115 232 235 Other (2) 8 22 38 86 Ending balance $ 20,399 $ 23,799 $ 20,399 $ 23,799 __________ (1) Benefit for loan losses is included in “ Benefit for credit losses ” in our condensed consolidated statements of operations and comprehensive income. (2) Amounts represent changes in other loss reserves which are reflected in benefit for loan losses, charge-offs, and recoveries. The following table displays the allowance for loan losses and recorded investment in our HFI loans, excluding loans for which we have elected the fair value option, by impairment or allowance methodology and portfolio segment. As of June 30, 2017 December 31, 2016 Single-Family Multifamily Total Single-Family Multifamily Total (Dollars in millions) Allowance for loan losses by segment: Individually impaired loans (1) $ 19,197 $ 41 $ 19,238 $ 21,920 $ 33 $ 21,953 Collectively reserved loans 1,021 140 1,161 1,363 149 1,512 Total allowance for loan losses $ 20,218 $ 181 $ 20,399 $ 23,283 $ 182 $ 23,465 Recorded investment in loans by segment: Individually impaired loans (1) $ 144,833 $ 487 $ 145,320 $ 155,598 $ 589 $ 156,187 Collectively reserved loans 2,745,268 246,141 2,991,409 2,708,337 231,292 2,939,629 Total recorded investment in loans $ 2,890,101 $ 246,628 $ 3,136,729 $ 2,863,935 $ 231,881 $ 3,095,816 __________ (1) Includes acquired credit-impaired loans.

Investments in Securities

Investments in Securities	6 Months Ended
	Jun. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Investments in Securities	Investments in Securities Trading Securities Trading securities are recorded at fair value with subsequent changes in fair value recorded as “ Fair value losses, net ” in our condensed consolidated statements of operations and comprehensive income. The following table displays our investments in trading securities. As of June 30, 2017 December 31, 2016 (Dollars in millions) Mortgage-related securities: Fannie Mae $ 4,277 $ 4,769 Other agency 1,969 2,058 Alt-A and subprime private-label securities 593 636 Commercial mortgage-backed securities (“CMBS”) 16 761 Mortgage revenue bonds 1 21 Total mortgage-related securities 6,856 8,245 U.S. Treasury securities 32,418 32,317 Total trading securities $ 39,274 $ 40,562 Available-for-Sale Securities We record available-for-sale (“AFS”) securities at fair value with unrealized gains and losses, recorded net of tax, as a component of “Other comprehensive income (loss)” and we recognize realized gains and losses from the sale of AFS securities in “ Investment gains, net ” in our condensed consolidated statements of operations and comprehensive income. The following table displays the gross realized gains, losses and proceeds on sales of AFS securities. For the Three For the Six Months Ended Months Ended June 30, June 30, 2017 2016 2017 2016 (Dollars in millions) Gross realized gains $ 227 $ 234 $ 230 $ 445 Gross realized losses — 8 — 12 Total proceeds (excludes initial sale of securities from new portfolio securitizations) 799 3,645 894 7,267 The following tables display the amortized cost, gross unrealized gains and losses, and fair value by major security type for AFS securities. As of June 30, 2017 Total Amortized Cost (1) Gross Unrealized Gains Gross Unrealized Losses (2) Total Fair Value (Dollars in millions) Fannie Mae $ 2,173 $ 124 $ (25 ) $ 2,272 Other agency 399 33 — 432 Alt-A and subprime private-label securities 1,335 828 (1 ) 2,162 CMBS 259 — — 259 Mortgage revenue bonds 858 21 (6 ) 873 Other mortgage-related securities 395 15 — 410 Total $ 5,419 $ 1,021 $ (32 ) $ 6,408 As of December 31, 2016 Total Amortized Cost (1) Gross Unrealized Gains Gross Unrealized Losses (2) Total Fair Value (Dollars in millions) Fannie Mae $ 2,445 $ 137 $ (28 ) $ 2,554 Other agency 508 39 — 547 Alt-A and subprime private-label securities 1,817 895 (3 ) 2,709 CMBS 815 4 — 819 Mortgage revenue bonds 1,245 36 (9 ) 1,272 Other mortgage-related securities 431 31 — 462 Total $ 7,261 $ 1,142 $ (40 ) $ 8,363 __________ (1) Amortized cost consists of unpaid principal balance, unamortized premiums, discounts and other cost basis adjustments, as well as net other-than-temporary impairments (“OTTI”) recognized in “ Investment gains, net ” in our condensed consolidated statements of operations and comprehensive income. (2) Represents the gross unrealized losses on securities for which we have not recognized OTTI, as well as the noncredit component of OTTI and cumulative changes in fair value of securities for which we previously recognized the credit component of OTTI in “ Accumulated other comprehensive income ” in our condensed consolidated balance sheets. The following tables display additional information regarding gross unrealized losses and fair value by major security type for AFS securities in an unrealized loss position. As of June 30, 2017 Less Than 12 Consecutive Months 12 Consecutive Months or Longer Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value (Dollars in millions) Fannie Mae $ (2 ) $ 194 $ (23 ) $ 443 Alt-A and subprime private-label securities — — (1 ) 64 Mortgage revenue bonds — — (6 ) 17 Total $ (2 ) $ 194 $ (30 ) $ 524 As of December 31, 2016 Less Than 12 Consecutive Months 12 Consecutive Months or Longer Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value (Dollars in millions) Fannie Mae $ (2 ) $ 139 $ (26 ) $ 477 Alt-A and subprime private-label securities — — (3 ) 73 Mortgage revenue bonds (7 ) 78 (2 ) 6 Total $ (9 ) $ 217 $ (31 ) $ 556 Other-Than-Temporary Impairments The balance of the unrealized credit loss component of AFS debt securities held by us and recognized in our condensed consolidated statements of operations and comprehensive income was $1.8 billion , $1.8 billion and $1.9 billion as of June 30, 2017 , March 31, 2017 and December 31, 2016 , respectively. The decrease in the six months ended June 30, 2017 was primarily driven by securities no longer held in portfolio at period end. The balance of the unrealized credit loss component of AFS debt securities held by us and recognized in our condensed consolidated statements of operations and comprehensive income was $2.2 billion , $2.3 billion and $2.4 billion as of June 30, 2016 , March 31, 2016 and December 31, 2015 , respectively. The decrease in the three months ended June 30, 2016 was primarily driven by changes in cash flows expected to be collected over the remaining life of the securities. The decrease in the six months ended June 30, 2016 was primarily driven by securities no longer held in portfolio at period end. Maturity Information The following table displays the amortized cost and fair value of our AFS securities by major security type and remaining contractual maturity, assuming no principal prepayments. The contractual maturity of mortgage-backed securities is not a reliable indicator of their expected life because borrowers generally have the right to prepay their obligations at any time. As of June 30, 2017 Total Amortized Cost Total Fair Value One Year or Less After One Year Through Five Years After Five Years Through Ten Years After Ten Years Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value (Dollars in millions) Fannie Mae $ 2,173 $ 2,272 $ 2 $ 2 $ 13 $ 14 $ 64 $ 68 $ 2,094 $ 2,188 Other agency 399 432 1 1 26 26 62 66 310 339 Alt-A and subprime private-label securities 1,335 2,162 — — — — — — 1,335 2,162 CMBS 259 259 259 259 — — — — — — Mortgage revenue bonds 858 873 10 10 75 75 112 114 661 674 Other mortgage-related securities 395 410 — — — — 3 3 392 407 Total $ 5,419 $ 6,408 $ 272 $ 272 $ 114 $ 115 $ 241 $ 251 $ 4,792 $ 5,770

Financial Guarantees

Financial Guarantees	6 Months Ended
	Jun. 30, 2017
Guarantees [Abstract]
Financial Guarantees	Financial Guarantees We recognize a guaranty obligation for our obligation to stand ready to perform on our guarantees to unconsolidated trusts and other guaranty arrangements. These guarantees expose us to credit losses on the mortgage loans or, in the case of mortgage-related securities, the underlying mortgage loans of the related securities. The remaining contractual terms of our guarantees range from 1 day to 35 years; however, the actual term of each guaranty may be significantly less than the contractual term based on the prepayment characteristics of the related mortgage loans. The following table displays our maximum exposure, guaranty obligation recognized in our condensed consolidated balance sheets, and the maximum potential recovery from third parties through available credit enhancements and recourse related to our financial guarantees. As of June 30, 2017 December 31, 2016 Maximum Exposure (1) Guaranty Obligation Maximum Recovery (2) Maximum Exposure (1) Guaranty Obligation Maximum Recovery (2) (Dollars in millions) Unconsolidated Fannie Mae MBS $ 11,619 $ 134 $ 7,636 $ 12,607 $ 143 $ 8,048 Other guaranty arrangements (3) 14,632 130 2,499 15,335 137 2,663 Total $ 26,251 $ 264 $ 10,135 $ 27,942 $ 280 $ 10,711 __________ (1) Primarily consists of the unpaid principal balance of the underlying mortgage loans. (2) Recoverability of such credit enhancements and recourse is subject to, among other factors, our mortgage insurers’ and financial guarantors’ ability to meet their obligations to us. For information on our mortgage insurers and financial guarantors, see “Note 15, Concentrations of Credit Risk” in our 2016 Form 10-K . (3) Primarily consists of credit enhancements and long-term standby commitments. The fair value of our guaranty obligations associated with the Fannie Mae MBS included in “Investments in securities” in our condensed consolidated balance sheets was $304 million and $446 million as of June 30, 2017 and December 31, 2016 , respectively. These Fannie Mae MBS consist primarily of private-label wraps where our guaranty arrangement is with an unconsolidated MBS trust.

Short-Term Borrowings and Long-

Short-Term Borrowings and Long-Term Debt	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Short-Term Borrowings and Long-Term Debt	Short-Term Borrowings and Long-Term Debt Short-Term Borrowings The following table displays our outstanding short-term borrowings (borrowings with an original contractual maturity of one year or less) and weighted-average interest rates of these borrowings. As of June 30, 2017 December 31, 2016 Outstanding Weighted- Average Interest Rate (1) Outstanding Weighted- Average Interest Rate (1) (Dollars in millions) Federal funds purchased and securities sold under agreements to repurchase (2) $ 7 0.25 % $ — — % Short-term debt of Fannie Mae $ 30,501 0.84 % $ 34,995 0.49 % Debt of consolidated trusts 511 0.91 584 0.48 Total short-term debt $ 31,012 0.84 % $ 35,579 0.49 % __________ (1) Includes the effects of discounts, premiums and other cost basis adjustments. (2) Represents agreements to repurchase securities for a specified price, with repayment generally occurring on the following day. Intraday Line of Credit We use a secured intraday funding line of credit provided by a large financial institution. We post collateral which, in some circumstances, the secured party has the right to repledge to third parties. As this line of credit is an uncommitted intraday loan facility, we may be unable to draw on it if and when needed. The line of credit under this facility was $15.0 billion as of June 30, 2017 and December 31, 2016 . We had no borrowings outstanding under this line of credit as of June 30, 2017 . Long-Term Debt Long-term debt represents borrowings with an original contractual maturity of greater than one year. The following table displays our outstanding long-term debt. As of June 30, 2017 December 31, 2016 Maturities Outstanding Weighted- Average Interest Rate (1) Maturities Outstanding Weighted- Average Interest Rate (1) (Dollars in millions) Senior fixed: Benchmark notes and bonds 2017 - 2030 $ 137,509 1.96 % 2017 - 2030 $ 153,983 2.16 % Medium-term notes (2) 2017 - 2026 82,215 1.42 2017 - 2026 82,230 1.40 Other (3) 2017 - 2038 7,926 4.82 2017 - 2038 12,800 6.74 Total senior fixed 227,650 1.87 249,013 2.14 Senior floating: Medium-term notes (2) 2017 - 2020 19,051 1.11 2017 - 2019 21,476 0.71 Connecticut Avenue Securities (4) 2023 - 2029 20,589 5.03 2023 - 2029 16,511 4.77 Other (5) 2020 - 2037 365 7.20 2020 - 2037 346 6.75 Total senior floating 40,005 3.14 38,333 2.48 Subordinated debentures 2019 4,870 9.93 2019 4,645 9.93 Secured borrowings (6) 2021 - 2022 94 1.60 2021 - 2022 111 1.44 Total long-term debt of Fannie Mae (7) 272,619 2.20 292,102 2.31 Debt of consolidated trusts 2017 - 2056 2,984,036 2.78 2017 - 2056 2,934,635 2.57 Total long-term debt $ 3,256,655 2.73 % $ 3,226,737 2.54 % __________ (1) Includes the effects of discounts, premiums and other cost basis adjustments. (2) Includes long-term debt with an original contractual maturity of greater than 1 year and up to 10 years, excluding zero-coupon debt. (3) Includes other long-term debt with an original contractual maturity of greater than 10 years and foreign exchange bonds. (4) Credit risk-sharing securities that transfer a portion of the credit risk on specified pools of single-family mortgage loans to the investors in these securities, a portion of which is reported at fair value. (5) Consists of structured debt instruments that are reported at fair value. (6) Represents our remaining liability resulting from the transfer of financial assets from our condensed consolidated balance sheets that did not qualify as a sale under the accounting guidance for the transfer of financial instruments. (7) Includes unamortized discounts and premiums, other cost basis adjustments and fair value adjustments of $1.0 billion and $1.8 billion as of June 30, 2017 and December 31, 2016 , respectively.

Derivative Instruments

Derivative Instruments	6 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	Derivative Instruments Derivative instruments are an integral part of our strategy in managing interest rate risk. Derivative instruments may be privately-negotiated, bilateral contracts, or they may be listed and traded on an exchange. We refer to our derivative transactions made pursuant to bilateral contracts as our over-the-counter (“OTC”) derivative transactions and our derivative transactions accepted for clearing by a derivatives clearing organization as our cleared derivative transactions. We typically do not settle the notional amount of our risk management derivatives; rather, notional amounts provide the basis for calculating actual payments or settlement amounts. The derivatives we use for interest rate risk management purposes consist primarily of interest rate swaps and interest rate options. We enter into various forms of credit risk sharing agreements, including credit risk transfer transactions, swap credit enhancements and mortgage insurance contracts, that we account for as derivatives. The majority of our credit-related derivatives are credit risk transfer transactions, whereby a portion of the credit risk associated with losses on a reference pool of mortgage loans is transferred to a third party. We enter into forward purchase and sale commitments that lock in the future delivery of mortgage loans and mortgage-related securities at a fixed price or yield. Certain commitments to purchase mortgage loans and purchase or sell mortgage-related securities meet the criteria of a derivative. We typically settle the notional amount of our mortgage commitments that are accounted for as derivatives. We recognize all derivatives as either assets or liabilities in our condensed consolidated balance sheets at their fair value on a trade date basis. Fair value amounts, which are netted to the extent a legal right of offset exists and is enforceable by law at the counterparty level and are inclusive of the right or obligation associated with the cash collateral posted or received, are recorded in “Other assets” or “Other liabilities” in our condensed consolidated balance sheets. See “ Note 14, Fair Value ” for additional information on derivatives recorded at fair value. We present cash flows from derivatives as operating activities in our condensed consolidated statements of cash flows. Notional and Fair Value Position of our Derivatives The following table displays the notional amount and estimated fair value of our asset and liability derivative instruments. As of June 30, 2017 As of December 31, 2016 Asset Derivatives Liability Derivatives Asset Derivatives Liability Derivatives Notional Amount Estimated Fair Value Notional Amount Estimated Fair Value Notional Amount Estimated Fair Value Notional Amount Estimated Fair Value (Dollars in millions) Risk management derivatives: Swaps: Pay-fixed $ 32,746 $ 441 $ 79,878 $ (2,983 ) $ 29,540 $ 660 $ 94,584 $ (4,396 ) Receive-fixed 33,890 2,604 134,172 (1,051 ) 30,207 2,696 135,470 (1,552 ) Basis 12,873 127 1,350 (1 ) 1,624 115 15,600 (11 ) Foreign currency 226 49 228 (72 ) 214 40 216 (85 ) Swaptions: Pay-fixed 10,250 179 2,350 (3 ) 9,600 241 4,850 (82 ) Receive-fixed — — 8,350 (271 ) — — 10,100 (257 ) Other (1) 24,203 23 — (1 ) 15,087 33 655 (2 ) Total gross risk management derivatives 114,188 3,423 226,328 (4,382 ) 86,272 3,785 261,475 (6,385 ) Accrued interest receivable (payable) — 707 — (754 ) — 785 — (937 ) Netting adjustment (2) — (4,024 ) — 5,034 — (4,514 ) — 6,844 Total net risk management derivatives $ 114,188 $ 106 $ 226,328 $ (102 ) $ 86,272 $ 56 $ 261,475 $ (478 ) Mortgage commitment derivatives: Mortgage commitments to purchase whole loans $ 1,898 $ 5 $ 6,698 $ (27 ) $ 4,753 $ 28 $ 3,039 $ (49 ) Forward contracts to purchase mortgage-related securities 11,791 37 69,343 (243 ) 31,635 198 27,297 (388 ) Forward contracts to sell mortgage-related securities 100,370 271 16,793 (48 ) 34,103 405 47,645 (300 ) Total mortgage commitment derivatives $ 114,059 $ 313 $ 92,834 $ (318 ) $ 70,491 $ 631 $ 77,981 $ (737 ) Derivatives at fair value $ 228,247 $ 419 $ 319,162 $ (420 ) $ 156,763 $ 687 $ 339,456 $ (1,215 ) __________ (1) Includes credit risk transfer transactions, futures, swap credit enhancements and mortgage insurance contracts that we account for as derivatives. (2) The netting adjustment represents the effect of the legal right to offset under legally enforceable master netting arrangements to settle with the same counterparty on a net basis, including cash collateral posted and received. Cash collateral posted was $1.6 billion and $2.9 billion as of June 30, 2017 and December 31, 2016 , respectively. Cash collateral received was $599 million and $535 million as of June 30, 2017 and December 31, 2016 , respectively. We record all derivative gains and losses, including accrued interest, in “ Fair value losses, net ” in our condensed consolidated statements of operations and comprehensive income. The following table displays, by type of derivative instrument, the fair value gains and losses, net on our derivatives. For the Three Months For the Six Months Ended June 30, Ended June 30, 2017 2016 2017 2016 (Dollars in millions) Risk management derivatives: Swaps: Pay-fixed $ (691 ) $ (2,257 ) $ — $ (7,430 ) Receive-fixed 639 1,371 322 4,358 Basis 16 14 23 49 Foreign currency 11 (34 ) 23 (31 ) Swaptions: Pay-fixed (48 ) 4 (48 ) 29 Receive-fixed (8 ) (19 ) (26 ) (136 ) Other 3 22 (5 ) 160 Net accrual of periodic settlements (224 ) (291 ) (479 ) (560 ) Total risk management derivatives fair value losses, net $ (302 ) $ (1,190 ) $ (190 ) $ (3,561 ) Mortgage commitment derivatives fair value losses, net (192 ) (367 ) (272 ) (729 ) Total derivatives fair value losses, net $ (494 ) $ (1,557 ) $ (462 ) $ (4,290 ) Derivative Counterparty Credit Exposure Our derivative counterparty credit exposure relates principally to interest rate derivative contracts. We are exposed to the risk that a counterparty in a derivative transaction will default on payments due to us, which may require us to seek a replacement derivative from a different counterparty. This replacement may be at a higher cost, or we may be unable to find a suitable replacement. We manage our derivative counterparty credit exposure relating to our risk management derivative transactions mainly through enforceable master netting arrangements, which allow us to net derivative assets and liabilities with the same counterparty or clearing organization and clearing member. For our OTC derivative transactions, we require counterparties to post collateral, which may include cash, U.S. Treasury securities, agency debt and agency mortgage-related securities. See “ Note 13, Netting Arrangements ” for information on our rights to offset assets and liabilities.

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The calculation of income available to common stockholders and earnings per share is based on the underlying premise that all income after payment of dividends on preferred shares is available to and will be distributed to common stockholders. However, as a result of our conservatorship status and the terms of the senior preferred stock, no amounts are available to distribute as dividends to common or preferred stockholders (other than to Treasury as holder of the senior preferred stock). The following table displays the computation of basic and diluted earnings per share of common stock. For the Three Months Ended June 30, For the Six Months Ended June 30, 2017 2016 2017 2016 (Dollars and shares in millions, except per share amounts) Net income $ 3,200 $ 2,946 $ 5,973 $ 4,082 Dividends distributed or available for distribution to senior preferred stockholder (1) (3,117 ) (2,869 ) (5,896 ) (3,788 ) Net income attributable to common stockholders $ 83 $ 77 $ 77 $ 294 Weighted-average common shares outstanding—Basic (2) 5,762 5,762 5,762 5,762 Convertible preferred stock 131 131 131 131 Weighted-average common shares outstanding—Diluted (2) 5,893 5,893 5,893 5,893 Earnings per share: Basic $ 0.01 $ 0.01 $ 0.01 $ 0.05 Diluted 0.01 0.01 0.01 0.05 __________ (1) Dividends distributed or available for distribution were calculated based on our net worth as of the end of the fiscal quarters, less the applicable capital reserve amount. See “ Note 1, Summary of Significant Accounting Policies ” in this report and in our 2016 Form 10-K for additional information on our senior preferred stock agreement and our payment of dividends to Treasury. (2) Includes 4.6 billion of weighted average shares of common stock that would be issued upon the full exercise of the warrant issued to Treasury from the date the warrant was issued through June 30, 2017 and 2016 .

Segment Reporting

Segment Reporting	6 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting We have two reportable business segments: Single-Family and Multifamily. Previously, we had a third reportable business segment, Capital Markets, which was incorporated into the Single-Family and Multifamily segments in the fourth quarter of 2016. Results of our two business segments are intended to reflect each segment as if it were a stand-alone business. We have revised the presentation of our segment results for the prior periods to be consistent with the current period presentation. For the Three Months Ended June 30, 2017 2016 Single-Family Multifamily Total Single-Family Multifamily Total (Dollars in millions) Net interest income (1) $ 4,366 $ 636 $ 5,002 $ 4,730 $ 556 $ 5,286 Fee and other income (2) 111 242 353 78 96 174 Net revenues 4,477 878 5,355 4,808 652 5,460 Investment gains, net (3) 321 64 385 280 118 398 Fair value gains (losses), net (4) (685 ) (6 ) (691 ) (1,679 ) 12 (1,667 ) Administrative expenses (600 ) (86 ) (686 ) (597 ) (81 ) (678 ) Credit-related income (5) Benefit for credit losses 1,255 12 1,267 1,596 5 1,601 Foreclosed property expense (32 ) (2 ) (34 ) (61 ) (2 ) (63 ) Total credit-related income 1,223 10 1,233 1,535 3 1,538 TCCA fees (6) (518 ) — (518 ) (453 ) — (453 ) Other expenses, net (155 ) (136 ) (291 ) (252 ) (2 ) (254 ) Income before federal income taxes 4,063 724 4,787 3,642 702 4,344 Provision for federal income taxes (1,401 ) (186 ) (1,587 ) (1,254 ) (144 ) (1,398 ) Net income $ 2,662 $ 538 $ 3,200 $ 2,388 $ 558 $ 2,946 For the Six Months Ended June 30, 2017 2016 Single-Family Multifamily Total Single-Family Multifamily Total (Dollars in millions) Net interest income (1) $ 9,122 $ 1,226 $ 10,348 $ 8,975 $ 1,080 $ 10,055 Fee and other income (2) 187 415 602 145 232 377 Net revenues 9,309 1,641 10,950 9,120 1,312 10,432 Investment gains, net (3) 271 105 376 336 131 467 Fair value gains (losses), net (4) (697 ) (34 ) (731 ) (4,529 ) 49 (4,480 ) Administrative expenses (1,201 ) (169 ) (1,370 ) (1,206 ) (160 ) (1,366 ) Credit-related income (5) Benefit for credit losses 1,655 8 1,663 2,759 26 2,785 Foreclosed property expense (248 ) (3 ) (251 ) (396 ) (1 ) (397 ) Total credit-related income 1,407 5 1,412 2,363 25 2,388 TCCA fees (6) (1,021 ) — (1,021 ) (893 ) — (893 ) Other expenses, net (411 ) (262 ) (673 ) (498 ) (20 ) (518 ) Income before federal income taxes 7,657 1,286 8,943 4,693 1,337 6,030 Provision for federal income taxes (2,653 ) (317 ) (2,970 ) (1,643 ) (305 ) (1,948 ) Net income $ 5,004 $ 969 $ 5,973 $ 3,050 $ 1,032 $ 4,082 __________ (1) Net interest income primarily consists of guaranty fees received as compensation for assuming and managing the credit risk on loans underlying Fannie Mae MBS held by third parties for the respective business segment, and the difference between the interest income earned on the respective business segment’s mortgage assets in our retained mortgage portfolio and the interest expense associated with the debt funding those assets. Revenues from single-family guaranty fees include revenues generated by the 10 basis point increase in guaranty fees we implemented in 2012 pursuant to TCCA. (2) Single-Family fee and other income primarily consists of compensation for engaging in structured transactions and providing other lender services, and income resulting from settlement agreements resolving certain claims relating to private-label securities sold to us or that we have guaranteed. Multifamily fee and other income consists of fees associated with multifamily business activities, including yield maintenance income. (3) Investment gains and losses primarily consists of gains and losses on the sale of mortgage assets for the respective business segment. (4) Single-Family fair value gains and losses primarily consist of fair value gains and losses on risk management and mortgage commitment derivatives, trading securities and other financial instruments associated with our single-family mortgage credit book of business. Multifamily fair value gains and losses primarily consist of fair value gains and losses on MBS commitment derivatives, trading securities and other financial instruments associated with our multifamily mortgage credit book of business. (5) Credit-related income or expense is based on the guaranty book of business of the respective business segment and consists of the applicable segment’s benefit or provision for credit losses and foreclosed property expense on loans underlying the segment’s guaranty book of business. (6) Consists of the portion of our single-family guaranty fees that is remitted to Treasury pursuant to the TCCA.

Equity

Equity	6 Months Ended
	Jun. 30, 2017
Equity [Abstract]
Equity	Equity The following table displays the activity in other comprehensive loss, net of tax, by major categories. For the Three Months Ended June 30, For the Six Months Ended June 30, 2017 2016 2017 2016 (Dollars in millions) Net income $ 3,200 $ 2,946 $ 5,973 $ 4,082 Other comprehensive loss, net of tax effect: Changes in net unrealized gains (losses) on AFS securities (net of tax of $6 and $27, respectively, for the three months ended and net of tax of $11 and $21, respectively, for the six months ended) 11 50 20 (39 ) Reclassification adjustment for OTTI recognized in net income (net of tax of $0 and $1, respectively, for the three months ended and net of tax of $0 and $11, respectively, for the six months ended) — 1 1 20 Reclassification adjustment for gains on AFS securities included in net income (net of tax of $50 and $68, respectively, for the three months ended and net of tax of $51 and $137, respectively, for the six months ended) (92 ) (126 ) (94 ) (254 ) Other (2 ) (2 ) (4 ) (4 ) Total other comprehensive loss (83 ) (77 ) (77 ) (277 ) Total comprehensive income $ 3,117 $ 2,869 $ 5,896 $ 3,805 The following table displays our accumulated other comprehensive income by major categories. As of June 30, December 31, 2017 2016 (Dollars in millions) Net unrealized gains on AFS securities for which we have not recorded OTTI, net of tax $ 108 $ 135 Net unrealized gains on AFS securities for which we have recorded OTTI, net of tax 535 581 Other, net of tax 39 43 Accumulated other comprehensive income $ 682 $ 759 The table below displays changes in accumulated other comprehensive income, net of tax. For the Three Months Ended June 30, For the Six Months Ended June 30, 2017 2016 2017 2016 AFS (1) Other Total AFS (1) Other Total AFS (1) Other Total AFS (1) Other Total (Dollars in millions) Beginning balance $ 724 $ 41 $ 765 $ 1,160 $ 47 $ 1,207 $ 716 $ 43 $ 759 $ 1,358 $ 49 $ 1,407 Other comprehensive income (loss) before reclassifications 11 — 11 50 — 50 20 — 20 (39 ) — (39 ) Amounts reclassified from other comprehensive income (loss) (92 ) (2 ) (94 ) (125 ) (2 ) (127 ) (93 ) (4 ) (97 ) (234 ) (4 ) (238 ) Net other comprehensive income (loss) (81 ) (2 ) (83 ) (75 ) (2 ) (77 ) (73 ) (4 ) (77 ) (273 ) (4 ) (277 ) Ending balance $ 643 $ 39 $ 682 $ 1,085 $ 45 $ 1,130 $ 643 $ 39 $ 682 $ 1,085 $ 45 $ 1,130 __________ (1) The amounts reclassified from accumulated other comprehensive income represent the gain or loss recognized in earnings due to a sale of an AFS security or the recognition of a net impairment recognized in earnings, which are recorded in “ Investment gains, net ” in our condensed consolidated statements of operations and comprehensive income.

Concentrations of Credit Risk

Concentrations of Credit Risk	6 Months Ended
	Jun. 30, 2017
Risks and Uncertainties [Abstract]
Concentrations of Credit Risk	Concentrations of Credit Risk Risk Characteristics of our Guaranty Book of Business One of the measures by which we gauge our performance risk under our guaranty is the delinquency status of the mortgage loans we hold in our retained mortgage portfolio, or in the case of mortgage-backed securities, the mortgage loans underlying the related securities. For single-family loans, management monitors the serious delinquency rate, which is the percentage of single-family loans 90 days or more past due or in the foreclosure process, and loans that have higher risk characteristics, such as high mark-to-market LTV ratios. For multifamily loans, management monitors the serious delinquency rate, which is the percentage of loans, based on unpaid principal balance, that are 60 days or more past due, and other loans that have higher risk characteristics, to determine our overall credit quality indicator. Higher risk characteristics include, but are not limited to, current debt service coverage ratio (“DSCR”) below 1.0 and high original LTV ratios. We stratify multifamily loans into different internal risk categories based on the credit risk inherent in each individual loan. For single-family and multifamily loans, we use this information, in conjunction with housing market and economic conditions, to structure our pricing and our eligibility and underwriting criteria to reflect the current risk of loans with these higher-risk characteristics, and in some cases we decide to significantly reduce our participation in riskier loan product categories. Management also uses this data together with other credit risk measures to identify key trends that guide the development of our loss mitigation strategies. The following tables display the delinquency status and serious delinquency rates for specified loan categories of our single-family conventional and total multifamily guaranty book of business. As of June 30, 2017 (1) December 31, 2016 (1) 30 Days Delinquent 60 Days Delinquent Seriously Delinquent (2) 30 Days Delinquent 60 Days Delinquent Seriously Delinquent (2) Percentage of single-family conventional guaranty book of business (3) 1.14 % 0.30 % 0.98 % 1.30 % 0.36 % 1.18 % Percentage of single-family conventional loans (4) 1.32 0.34 1.01 1.51 0.41 1.20 As of June 30, 2017 (1) December 31, 2016 (1) Percentage of Single-Family Conventional Guaranty Book of Business (3) Seriously Delinquent Rate (2) Percentage of Single-Family Conventional Guaranty Book of Business (3) Seriously Delinquent Rate (2) Estimated mark-to-market loan-to-value ratio: Greater than 100% 1 % 10.05 % 2 % 10.44 % Geographical distribution: California 19 0.43 19 0.50 Florida 6 1.51 6 1.89 New Jersey 4 2.49 4 3.07 New York 5 2.21 5 2.65 All other states 66 0.94 66 1.11 Product distribution: Alt-A 3 4.52 3 5.00 Vintages: 2004 and prior 4 2.62 5 2.82 2005-2008 7 5.73 8 6.39 2009-2017 89 0.32 87 0.36 __________ (1) Consists of the portion of our single-family conventional guaranty book of business for which we have detailed loan level information, which constituted approximately 99% of our total single-family conventional guaranty book of business as of June 30, 2017 and December 31, 2016 . (2) Consists of single-family conventional loans that were 90 days or more past due or in the foreclosure process as of June 30, 2017 and December 31, 2016 . (3) Calculated based on the aggregate unpaid principal balance of single-family conventional loans for each category divided by the aggregate unpaid principal balance of loans in our single-family conventional guaranty book of business. (4) Calculated based on the number of single-family conventional loans that were delinquent divided by the total number of loans in our single-family conventional guaranty book of business. As of June 30, 2017 (1)(2) December 31, 2016 (1)(2) 30 Days Delinquent Seriously Delinquent (3) 30 Days Delinquent Seriously Delinquent (3) Percentage of multifamily guaranty book of business 0.01 % 0.04 % 0.02 % 0.05 % As of June 30, 2017 (1) December 31, 2016 (1) Percentage of Multifamily Guaranty Book of Business (2) Percentage Seriously Delinquent (3)(4) Percentage of Multifamily Guaranty Book of Business (2) Percentage Seriously Delinquent (3)(4) Original LTV ratio: Greater than 80% 2 % 0.17 % 2 % 0.22 % Less than or equal to 80% 98 0.04 98 0.05 Current DSCR less than 1.0 (5) 1 2.12 2 1.96 __________ (1) Consists of the portion of our multifamily guaranty book of business for which we have detailed loan level information, which constituted approximately 99% of our total multifamily guaranty book of business as of June 30, 2017 and December 31, 2016 , excluding loans that have been defeased. (2) Calculated based on the aggregate unpaid principal balance of multifamily loans for each category divided by the aggregate unpaid principal balance of loans in our multifamily guaranty book of business. (3) Consists of multifamily loans that were 60 days or more past due as of the dates indicated. (4) Calculated based on the unpaid principal balance of multifamily loans that were seriously delinquent divided by the aggregate unpaid principal balance of multifamily loans for each category included in our guaranty book of business. (5) Our estimates of current DSCRs are based on the latest available income information for these properties. Although we use the most recently available results of our multifamily borrowers, there is a lag in reporting, which typically can range from 3 to 6 months but in some cases may be longer. Other Concentrations Mortgage Sellers and Servicers. Mortgage servicers collect mortgage and escrow payments from borrowers, pay taxes and insurance costs from escrow accounts, monitor and report delinquencies, and perform other required activities on our behalf. Our mortgage sellers and servicers may also be obligated to repurchase loans or foreclosed properties, reimburse us for losses or provide other remedies under certain circumstances, such as if it is determined that the mortgage loan did not meet our underwriting or eligibility requirements, if certain loan representations and warranties are violated or if mortgage insurers rescind coverage. However, under our revised representation and warranty framework, we no longer require repurchase for loans that have breaches of certain selling representations and warranties if they have met specified criteria for relief. Our business with mortgage servicers is concentrated. Our five largest single-family mortgage servicers, including their affiliates, serviced approximately 40% of our single-family guaranty book of business as of June 30, 2017 , compared with approximately 39% as of December 31, 2016 . Our five largest multifamily mortgage servicers, including their affiliates, serviced approximately 47% of our multifamily guaranty book of business as of June 30, 2017 and December 31, 2016 . If a significant mortgage seller or servicer counterparty, or a number of mortgage sellers or servicers, fails to meet their obligations to us, it could increase our credit losses and credit-related expense, and adversely affect our results of operations and financial condition. Mortgage Insurers. Mortgage insurance “risk in force” generally represents our maximum potential loss recovery under the applicable mortgage insurance policies. We had total mortgage insurance coverage risk in force of $131.5 billion and $126.2 billion on the single-family mortgage loans in our guaranty book of business as of June 30, 2017 and December 31, 2016 , respectively, which represented 5% and 4% of our single-family guaranty book of business as of June 30, 2017 and December 31, 2016 , respectively. Our primary mortgage insurance coverage risk in force was $130.9 billion and $125.6 billion as of June 30, 2017 and December 31, 2016 , respectively. Our pool mortgage insurance coverage risk in force was $565 million and $617 million as of June 30, 2017 and December 31, 2016 , respectively. Our top three mortgage insurance companies provided 66% of our mortgage insurance coverage risk in force as of June 30, 2017 and December 31, 2016 . Of our largest primary mortgage insurers, PMI Mortgage Insurance Co., Triad Guaranty Insurance Corporation and Republic Mortgage Insurance Company are under various forms of supervised control by their state regulators and are in run-off. Entering run-off may close off a source of profits and liquidity that may have otherwise assisted a mortgage insurer in paying claims under insurance policies, and could also cause the quality and speed of its claims processing to deteriorate. These three mortgage insurers provided a combined $7.1 billion , or 5% , of our risk in force mortgage insurance coverage of our single-family guaranty book of business as of June 30, 2017 . We have counterparty credit risk relating to the potential insolvency of, or non-performance by, mortgage insurers that insure single-family loans we purchase or guarantee. There is risk that these counterparties may fail to fulfill their obligations to pay our claims under insurance policies. If we determine that it is probable that we will not collect all of our claims from one or more of our mortgage insurer counterparties, it could increase our loss reserves, which could adversely affect our results of operations, liquidity, financial condition and net worth. When we estimate the credit losses that are inherent in our mortgage loans and under the terms of our guaranty obligations we also consider the recoveries that we will receive on primary mortgage insurance, as mortgage insurance recoveries would reduce the severity of the loss associated with defaulted loans. We evaluate the financial condition of our mortgage insurer counterparties and adjust the contractually due recovery amounts to ensure that only probable losses as of the balance sheet date are included in our loss reserve estimate. As a result, if our assessment of one or more of our mortgage insurer counterparties’ ability to fulfill their respective obligations to us worsens, it could increase our combined loss reserves. As of June 30, 2017 and December 31, 2016 , the amount by which our estimated benefit from mortgage insurance reduced our combined loss reserves was $1.1 billion and $1.4 billion , respectively. We had outstanding receivables of $926 million recorded in “Other assets” in our condensed consolidated balance sheets as of June 30, 2017 and $1.0 billion as of December 31, 2016 related to amounts claimed on insured, defaulted loans excluding government-insured loans. Of this amount, $106 million as of June 30, 2017 and $141 million as of December 31, 2016 was due from our mortgage sellers or servicers. We assessed the total outstanding receivables for collectibility, and they are recorded net of a valuation allowance of $612 million as of June 30, 2017 and $638 million as of December 31, 2016 . The valuation allowance reduces our claim receivable to the amount which is considered probable of collection as of June 30, 2017 and December 31, 2016 . For information on credit risk associated with our derivative transactions and repurchase agreements refer to “ Note 8, Derivative Instruments ” and “ Note 13, Netting Arrangements .”

Netting Arrangements

Netting Arrangements	6 Months Ended
	Jun. 30, 2017
Offsetting [Abstract]
Netting Arrangements	Netting Arrangements We use master netting arrangements, which allow us to offset certain financial instruments and collateral with the same counterparty, to minimize counterparty credit exposure. The tables below display information related to derivatives, securities purchased under agreements to resell or similar arrangements, and securities sold under agreements to repurchase or similar arrangements, which are subject to an enforceable master netting arrangement or similar agreement that are either offset or not offset in our condensed consolidated balance sheets. As of June 30, 2017 Net Amount Presented in our Condensed Consolidated Balance Sheets Amounts Not Offset in our Condensed Consolidated Balance Sheets Gross Amount Gross Amount Offset (1) Financial Instruments (2) Collateral (3) Net Amount (Dollars in millions) Assets: OTC risk management derivatives $ 2,800 $ (2,753 ) $ 47 $ — $ — $ 47 Cleared risk management derivatives 1,307 (1,271 ) 36 — — 36 Mortgage commitment derivatives 313 — 313 (234 ) — 79 Total derivative assets 4,420 (4,024 ) 396 (4) (234 ) — 162 Securities purchased under agreements to resell or similar arrangements (5) 41,120 — 41,120 — (41,120 ) — Total assets $ 45,540 $ (4,024 ) $ 41,516 $ (234 ) $ (41,120 ) $ 162 Liabilities: OTC risk management derivatives $ (3,564 ) $ 3,465 $ (99 ) $ — $ — $ (99 ) Cleared risk management derivatives (1,571 ) 1,569 (2 ) — 2 — Mortgage commitment derivatives (318 ) — (318 ) 234 — (84 ) Total derivative liabilities (5,453 ) 5,034 (419 ) (4) 234 2 (183 ) Securities sold under agreements to repurchase or similar arrangements (7 ) — (7 ) — 7 — Total liabilities $ (5,460 ) $ 5,034 $ (426 ) $ 234 $ 9 $ (183 ) As of December 31, 2016 Net Amount Presented in our Condensed Consolidated Balance Sheets Amounts Not Offset in our Condensed Consolidated Balance Sheets Gross Amount Gross Amount Offset (1) Financial Instruments (2) Collateral (3) Net Amount (Dollars in millions) Assets: OTC risk management derivatives $ 3,688 $ (3,667 ) $ 21 $ — $ — $ 21 Cleared risk management derivatives 849 (847 ) 2 — — 2 Mortgage commitment derivatives 631 — 631 (357 ) (22 ) 252 Total derivative assets 5,168 (4,514 ) 654 (4) (357 ) (22 ) 275 Securities purchased under agreements to resell or similar arrangements (5) 51,115 — 51,115 — (51,115 ) — Total assets $ 56,283 $ (4,514 ) $ 51,769 $ (357 ) $ (51,137 ) $ 275 Liabilities: OTC risk management derivatives $ (4,905 ) $ 4,520 $ (385 ) $ — $ — $ (385 ) Cleared risk management derivatives (2,415 ) 2,324 (91 ) — 91 — Mortgage commitment derivatives (737 ) — (737 ) 357 16 (364 ) Total derivative liabilities (8,057 ) 6,844 (1,213 ) (4) 357 107 (749 ) Total liabilities $ (8,057 ) $ 6,844 $ (1,213 ) $ 357 $ 107 $ (749 ) __________ (1) Represents the effect of the right to offset under legally enforceable master netting arrangements to settle with the same counterparty on a net basis, including cash collateral posted and received and accrued interest. (2) Mortgage commitment derivative amounts reflect where we have recognized both an asset and a liability with the same counterparty under an enforceable master netting arrangement but we have not elected to offset the related amounts in our condensed consolidated balance sheets. (3) Represents non-cash collateral received that has not been recognized and not offset in our condensed consolidated balance sheets as well as non-cash collateral posted which has been recognized but not offset in our condensed consolidated balance sheets. Does not include collateral held or posted in excess of our exposure. The fair value of non-cash collateral we pledged was $1.0 billion and $1.3 billion as of June 30, 2017 and December 31, 2016 , respectively, which the counterparty was permitted to sell or repledge. The fair value of non-cash collateral received was $41.2 billion and $51.2 billion , of which $38.9 billion and $45.5 billion could be sold or repledged as of June 30, 2017 and December 31, 2016 , respectively. None of the underlying collateral was sold or repledged as of June 30, 2017 and December 31, 2016 . (4) Excludes derivative assets of $23 million and $33 million as of June 30, 2017 and December 31, 2016 , and derivative liabilities of $1 million and $2 million recognized in our condensed consolidated balance sheets as of June 30, 2017 and December 31, 2016 , respectively, that are not subject to enforceable master netting arrangements. (5) Includes $11.9 billion and $20.7 billion of securities purchased under agreements to resell classified as “Cash and cash equivalents” in our condensed consolidated balance sheets as of June 30, 2017 and December 31, 2016 , respectively. Derivative instruments are recorded at fair value and securities purchased under agreements to resell or similar arrangements are recorded at amortized cost in our condensed consolidated balance sheets. We determine our rights to offset the assets and liabilities presented above with the same counterparty, including collateral posted or received, based on the contractual arrangements entered into with our individual counterparties and various rules and regulations that would govern the insolvency of a derivative counterparty. The following is a description, under various agreements, of the nature of those rights and their effect or potential effect on our financial position. The terms of the majority of our contracts for OTC risk management derivatives are governed under master agreements of the International Swaps and Derivatives Association Inc. (“ISDA”). These agreements provide that all transactions entered into under the agreement with the counterparty constitute a single contractual relationship. An event of default by the counterparty allows the early termination of all outstanding transactions under the same ISDA agreement and we may offset all outstanding amounts related to the terminated transactions including collateral posted or received. The terms of our contracts for cleared derivatives are governed under the rules of the clearing organization and the agreement between us and the clearing member of that clearing organization. In the event of a clearing organization default, all open positions at the clearing organization are closed and a net position (on a clearing member by clearing member basis) is calculated. Unless otherwise transferred, in the event of a clearing member default, all open positions cleared through that clearing member are closed and a net position is calculated. The terms of our contracts for mortgage commitment derivatives are primarily governed by the Fannie Mae Single-Family Selling Guide (“Guide”), for Fannie Mae-approved lenders, or Master Securities Forward Transaction Agreements (“MSFTA”), for counterparties that are not Fannie Mae-approved lenders. In the event of default by the counterparty, both the Guide and the MSFTA allow us to terminate all outstanding transactions under the applicable agreement and offset all outstanding amounts related to the terminated transactions including collateral posted or received. Under the Guide, upon a lender event of default, we generally may offset any amounts owed to a lender against any amounts a lender may owe us under any other existing agreement, regardless of whether or not such other agreements are in default or payments are immediately due. The terms of our contracts for securities purchased under agreements to resell and securities sold under agreements to repurchase are governed by Master Repurchase Agreements, which are based on the guidelines prescribed by the Securities Industry and Financial Markets Association. Master Repurchase Agreements provide that all transactions under the agreement constitute a single contractual relationship. An event of default by the counterparty allows the early termination of all outstanding transactions under the same agreement and we may offset all outstanding amounts related to the terminated transactions including collateral posted or received. We also have securities purchased under agreements to resell which we transact through the Fixed Income Clearing Corporation (“FICC”). Under the rules of the FICC, all agreements for securities purchased under agreements to resell that are submitted to the FICC for clearing become transactions with the FICC that are subject to FICC clearing rules. In the event of a FICC default, all open positions at the FICC are closed and a net position is calculated.

Fair Value

Fair Value	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value	Fair Value We use fair value measurements for the initial recording of certain assets and liabilities and periodic remeasurement of certain assets and liabilities on a recurring or nonrecurring basis. Fair Value Measurement Fair value measurement guidance defines fair value, establishes a framework for measuring fair value, and sets forth disclosures around fair value measurements. This guidance applies whenever other accounting guidance requires or permits assets or liabilities to be measured at fair value. The guidance establishes a three-level fair value hierarchy that prioritizes the inputs into the valuation techniques used to measure fair value. The fair value hierarchy gives the highest priority, Level 1, to measurements based on unadjusted quoted prices in active markets for identical assets or liabilities. The next highest priority, Level 2, is given to measurements of assets and liabilities based on limited observable inputs or observable inputs for similar assets and liabilities. The lowest priority, Level 3, is given to measurements based on unobservable inputs. Recurring Changes in Fair Value The following tables display our assets and liabilities measured in our condensed consolidated balance sheets at fair value on a recurring basis subsequent to initial recognition, including instruments for which we have elected the fair value option. Fair Value Measurements as of June 30, 2017 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Netting Adjustment (1) Estimated Fair Value (Dollars in millions) Recurring fair value measurements: Assets: Trading securities: Mortgage-related securities: Fannie Mae $ — $ 2,406 $ 1,871 $ — $ 4,277 Other agency — 1,969 — — 1,969 Alt-A and subprime private-label securities — 329 264 — 593 CMBS — 16 — — 16 Mortgage revenue bonds — — 1 — 1 Non-mortgage-related securities: U.S. Treasury securities 32,418 — — — 32,418 Total trading securities 32,418 4,720 2,136 — 39,274 Available-for-sale securities: Mortgage-related securities: Fannie Mae — 2,066 206 — 2,272 Other agency — 432 — — 432 Alt-A and subprime private-label securities — 1,984 178 — 2,162 CMBS — 259 — — 259 Mortgage revenue bonds — — 873 — 873 Other — 30 380 — 410 Total available-for-sale securities — 4,771 1,637 — 6,408 Mortgage loans — 10,287 1,119 — 11,406 Other assets: Risk management derivatives: Swaps — 3,784 144 — 3,928 Swaptions — 179 — — 179 Other — — 23 — 23 Netting adjustment — — — (4,024 ) (4,024 ) Mortgage commitment derivatives — 313 — — 313 Total other assets — 4,276 167 (4,024 ) 419 Total assets at fair value $ 32,418 $ 24,054 $ 5,059 $ (4,024 ) $ 57,507 Fair Value Measurements as of June 30, 2017 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Netting Adjustment (1) Estimated Fair Value (Dollars in millions) Liabilities: Long-term debt: Of Fannie Mae: Senior floating $ — $ 8,643 $ 365 $ — $ 9,008 Total of Fannie Mae — 8,643 365 — 9,008 Of consolidated trusts — 34,106 760 — 34,866 Total long-term debt — 42,749 1,125 — 43,874 Other liabilities: Risk management derivatives: Swaps — 4,837 24 — 4,861 Swaptions — 274 — — 274 Other — — 1 — 1 Netting adjustment — — — (5,034 ) (5,034 ) Mortgage commitment derivatives — 300 18 — 318 Total other liabilities — 5,411 43 (5,034 ) 420 Total liabilities at fair value $ — $ 48,160 $ 1,168 $ (5,034 ) $ 44,294 Fair Value Measurements as of December 31, 2016 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Netting Adjustment (1) Estimated Fair Value (Dollars in millions) Assets: Trading securities: Mortgage-related securities: Fannie Mae $ — $ 3,934 $ 835 $ — $ 4,769 Other agency — 2,058 — — 2,058 Alt-A and subprime private-label securities — 365 271 — 636 CMBS — 761 — — 761 Mortgage revenue bonds — — 21 — 21 Non-mortgage-related securities: U.S. Treasury securities 32,317 — — — 32,317 Total trading securities 32,317 7,118 1,127 — 40,562 Available-for-sale securities: Mortgage-related securities: Fannie Mae — 2,324 230 — 2,554 Other agency — 542 5 — 547 Alt-A and subprime private-label securities — 2,492 217 — 2,709 CMBS — 819 — — 819 Mortgage revenue bonds — — 1,272 — 1,272 Other — 33 429 — 462 Total available-for-sale securities — 6,210 2,153 — 8,363 Mortgage loans — 10,860 1,197 — 12,057 Other assets: Risk management derivatives: Swaps — 4,159 137 — 4,296 Swaptions — 241 — — 241 Other — — 33 — 33 Netting adjustment — — — (4,514 ) (4,514 ) Mortgage commitment derivatives — 619 12 — 631 Total other assets — 5,019 182 (4,514 ) 687 Total assets at fair value $ 32,317 $ 29,207 $ 4,659 $ (4,514 ) $ 61,669 Fair Value Measurements as of December 31, 2016 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Netting Adjustment (1) Estimated Fair Value (Dollars in millions) Liabilities: Long-term debt: Of Fannie Mae: Senior floating $ — $ 9,235 $ 347 $ — $ 9,582 Total of Fannie Mae — 9,235 347 — 9,582 Of consolidated trusts — 36,283 241 — 36,524 Total long-term debt — 45,518 588 — 46,106 Other liabilities: Risk management derivatives: Swaps — 6,933 48 — 6,981 Swaptions — 339 — — 339 Other — — 2 — 2 Netting adjustment — — — (6,844 ) (6,844 ) Mortgage commitment derivatives — 649 88 — 737 Total other liabilities — 7,921 138 (6,844 ) 1,215 Total liabilities at fair value $ — $ 53,439 $ 726 $ (6,844 ) $ 47,321 __________ (1) Derivative contracts are reported on a gross basis by level. The netting adjustment represents the effect of the legal right to offset under legally enforceable master netting arrangements to settle with the same counterparty on a net basis, including cash collateral posted and received. The following tables display a reconciliation of all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3). The tables also display gains and losses due to changes in fair value, including realized and unrealized gains and losses, recognized in our condensed consolidated statements of operations and comprehensive income for Level 3 assets and liabilities. When assets and liabilities are transferred between levels, we recognize the transfer as of the end of the period. Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Three Months Ended June 30, 2017 Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of June 30, 2017 (5)(6) Total Gains (Losses) (Realized/Unrealized) Balance, March 31, 2017 Included in Net Income Included in Total Other Comprehensive Income (Loss) (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 Transfers into Level 3 (4) Balance, June 30, 2017 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 856 $ 1 $ — $ 63 $ — $ — $ (2 ) $ (21 ) $ 974 $ 1,871 $ — Alt-A and subprime private-label securities 272 3 — — — — (11 ) — — 264 2 Mortgage revenue bonds 20 3 — — (21 ) — (1 ) — — 1 — Total trading securities $ 1,148 $ 7 (6)(7) $ — $ 63 $ (21 ) $ — $ (14 ) $ (21 ) $ 974 $ 2,136 $ 2 Available-for-sale securities: Mortgage-related: Fannie Mae $ 232 $ — $ (3 ) $ — $ — $ — $ (2 ) $ (21 ) $ — $ 206 $ — Alt-A and subprime private-label securities 205 — (21 ) — — — (6 ) — — 178 — Mortgage revenue bonds 1,185 34 (11 ) — (312 ) — (23 ) — — 873 — Other 417 — (19 ) — — — (18 ) — — 380 — Total available-for-sale securities $ 2,039 $ 34 (7)(8) $ (54 ) $ — $ (312 ) $ — $ (49 ) $ (21 ) $ — $ 1,637 $ — Mortgage loans $ 1,149 $ 24 (6)(7) $ — $ — $ — $ — $ (55 ) $ (21 ) $ 22 $ 1,119 $ 19 Net derivatives 113 27 (6) — — — — (16 ) — — 124 9 Long-term debt: Of Fannie Mae: Senior floating $ (350 ) $ (15 ) $ — $ — $ — $ — $ — $ — $ — $ (365 ) $ (14 ) Of consolidated trusts (214 ) (5 ) — — — — 12 22 (575 ) (760 ) (5 ) Total long-term debt $ (564 ) $ (20 ) (6) $ — $ — $ — $ — $ 12 $ 22 $ (575 ) $ (1,125 ) $ (19 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Six Months Ended June 30, 2017 Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of June 30, 2017 (5)(6) Total Gains (Losses) (Realized/Unrealized) Balance, December 31, 2016 Included in Net Income Included in Total Other Comprehensive Income (Loss) (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 Transfers into Level 3 (4) Balance, June 30, 2017 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 835 $ 4 $ — $ 63 $ — $ — $ (5 ) $ (22 ) $ 996 $ 1,871 $ 2 Alt-A and subprime private-label securities 271 11 — — — — (18 ) — — 264 11 Mortgage revenue bonds 21 3 — — (21 ) — (2 ) — — 1 — Total trading securities $ 1,127 $ 18 (6)(7) $ — $ 63 $ (21 ) $ — $ (25 ) $ (22 ) $ 996 $ 2,136 $ 13 Available-for-sale securities: Mortgage-related: Fannie Mae $ 230 $ 1 $ (2 ) $ — $ — $ — $ (6 ) $ (47 ) $ 30 $ 206 $ — Other agency 5 — — — (1 ) — — (4 ) — — — Alt-A and subprime private-label securities 217 — (15 ) — — — (24 ) — — 178 — Mortgage revenue bonds 1,272 35 (12 ) — (324 ) — (98 ) — — 873 — Other 429 — (14 ) — — — (35 ) — — 380 — Total available-for-sale securities $ 2,153 $ 36 (7)(8) $ (43 ) $ — $ (325 ) $ — $ (163 ) $ (51 ) $ 30 $ 1,637 $ — Mortgage loans $ 1,197 $ 32 (6)(7) $ — $ — $ — $ — $ (117 ) $ (67 ) $ 74 $ 1,119 $ 16 Net derivatives 44 100 (6) — — — — (24 ) 5 (1 ) 124 — Long-term debt: Of Fannie Mae: Senior floating $ (347 ) $ (18 ) $ — $ — $ — $ — $ — $ — $ — $ (365 ) $ (18 ) Of consolidated trusts (241 ) (4 ) — — — (2 ) 19 88 (620 ) (760 ) (4 ) Total long-term debt $ (588 ) $ (22 ) (6) $ — $ — $ — $ (2 ) $ 19 $ 88 $ (620 ) $ (1,125 ) $ (22 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Three Months Ended June 30, 2016 Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of June 30, 2016 (5)(6) Total Gains (Losses) (Realized/Unrealized) Balance, March 31, 2016 Included in Net Income Included in Total Other Comprehensive Income (Loss) (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 Transfers into Level 3 Balance, June 30, 2016 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 25 $ — $ — $ — $ — $ — $ (1 ) $ (24 ) $ — $ — $ — Other agency 1 — — — — — — (1 ) — — — Alt-A and subprime private-label securities 288 27 — — — — (12 ) — — 303 27 Mortgage revenue bonds 363 17 — — (184 ) — (3 ) — — 193 6 Total trading securities $ 677 $ 44 (6)(7) $ — $ — $ (184 ) $ — $ (16 ) $ (25 ) $ — $ 496 $ 33 Available-for-sale securities: Mortgage-related: Fannie Mae $ 1 $ — $ — $ — $ — $ — $ — $ (1 ) $ — $ — $ — Other agency 2 — — — — — — (1 ) — 1 — Alt-A and subprime private-label securities 399 1 9 — — — (61 ) — — 348 — Mortgage revenue bonds 2,564 76 18 — (568 ) — (61 ) — — 2,029 — Other 655 3 (1 ) — (201 ) — (6 ) — — 450 — Total available-for-sale securities $ 3,621 $ 80 (7)(8) $ 26 $ — $ (769 ) $ — $ (128 ) $ (2 ) $ — $ 2,828 $ — Mortgage loans $ 1,311 $ 15 (6)(7) $ — $ 25 $ — $ — $ (67 ) $ (19 ) $ 15 $ 1,280 $ 10 Net derivatives 231 52 (6) — — — (3 ) (33 ) — 1 248 41 Long-term debt: Of Fannie Mae: Senior floating $ (395 ) $ (15 ) $ — $ — $ — $ — $ — $ — $ — $ (410 ) $ (15 ) Of consolidated trusts (246 ) (7 ) — — — (47 ) 9 8 (43 ) (326 ) (7 ) Total long-term debt $ (641 ) $ (22 ) (6) $ — $ — $ — $ (47 ) $ 9 $ 8 $ (43 ) $ (736 ) $ (22 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Six Months Ended June 30, 2016 Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of June 30, 2016 (5)(6) Total Gains (Losses) (Realized/Unrealized) Balance, December 31, 2015 Included in Net Income Included in Total Other Comprehensive Income (Loss) (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 (4) Transfers into Level 3 Balance, June 30, 2016 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ — $ — $ — $ — $ — $ — $ (1 ) $ (24 ) $ 25 $ — $ — Other agency — — — — — — — (1 ) 1 — — Alt-A and subprime private-label securities 949 (64 ) — — (187 ) — (32 ) (363 ) — 303 (40 ) Mortgage revenue bonds 449 29 — — (279 ) — (6 ) — — 193 10 Total trading securities $ 1,398 $ (35 ) (6)(7) $ — $ — $ (466 ) $ — $ (39 ) $ (388 ) $ 26 $ 496 $ (30 ) Available-for-sale securities: Mortgage-related: Fannie Mae $ — $ — $ — $ — $ — $ — $ — $ (1 ) $ 1 $ — $ — Other agency 4 — — — — — — (3 ) — 1 — Alt-A and subprime private-label securities 4,322 104 (159 ) — (875 ) — (205 ) (2,839 ) — 348 — Mortgage revenue bonds 2,701 80 48 — (611 ) — (189 ) — — 2,029 — Other 1,404 — (26 ) — (605 ) — (39 ) (284 ) — 450 — Total available-for-sale securities $ 8,431 $ 184 (7)(8) $ (137 ) $ — $ (2,091 ) $ — $ (433 ) $ (3,127 ) $ 1 $ 2,828 $ — Mortgage loans $ 1,477 $ 116 (6)(7) $ — $ 25 $ (320 ) $ — $ (139 ) $ (84 ) $ 205 $ 1,280 $ 20 Net derivatives 157 232 (6) — — — (7 ) (133 ) (2 ) 1 248 76 Long-term debt: Of Fannie Mae: Senior floating $ (369 ) $ (41 ) $ — $ — $ — $ — $ — $ — $ — $ (410 ) $ (41 ) Of consolidated trusts (496 ) (75 ) — — — (54 ) 318 45 (64 ) (326 ) (8 ) Total long-term debt $ (865 ) $ (116 ) (6) $ — $ — $ — $ (54 ) $ 318 $ 45 $ (64 ) $ (736 ) $ (49 ) __________ (1) Gains (losses) included in other comprehensive income (loss) are included in “Changes in unrealized gains on AFS securities, net of reclassification adjustments and taxes” in our condensed consolidated statements of operations and comprehensive income. (2) Purchases and sales include activity related to the consolidation and deconsolidation of assets of securitization trusts. (3) Issues and settlements include activity related to the consolidation and deconsolidation of liabilities of securitization trusts. (4) Transfers into Level 3 during the second quarter and first half of 2017 consisted primarily of a Fannie Mae security backed by private-label mortgage-related securities. Prices for this security were based on inputs that were not readily available. Transfers out of Level 3 during the first half of 2016 consisted primarily of private-label mortgage-related securities backed by Alt-A loans and subprime loans. Prices for these securities were available from multiple third-party vendors and demonstrated an increased and sustained level of observability over time. (5) Amount represents temporary changes in fair value. Amortization, accretion and OTTI are not considered unrealized and are not included in this amount. (6) Gains (losses) are included in “ Fair value losses, net ” in our condensed consolidated statements of operations and comprehensive income. (7) Gains (losses) are included in “ Net interest income ” in our condensed consolidated statements of operations and comprehensive income. (8) Gains (losses) are included in “ Investment gains, net ” in our condensed consolidated statements of operations and comprehensive income. The following tables display valuation techniques and the range and the weighted average of significant unobservable inputs for our Level 3 assets and liabilities measured at fair value on a recurring basis. Fair Value Measurements as of June 30, 2017 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Recurring fair value measurements: Trading securities: Mortgage-related securities: Agency (2) $ 1,815 Single Vendor Prepayment Speed (%) 0.0 - 177.0 170.4 Spreads (bps) 32.7 - 210.0 186.0 56 Various Total agency 1,871 Alt-A and subprime private-label securities 264 Consensus Mortgage revenue bonds 1 Various Total trading securities $ 2,136 Available-for-sale securities: Mortgage-related securities: Agency (2) $ 206 Various Alt-A and subprime private-label securities 178 Various Mortgage revenue bonds 656 Single Vendor Spreads (bps) 4.5 - 366.8 58.1 145 Discounted Cash Flow Spreads (bps) 4.5 - 413.3 193.6 72 Various Total mortgage revenue bonds 873 Other 309 Discounted Cash Flow Default Rate (%) 1.2 1.2 Prepayment Speed (%) 0.5 0.5 Severity (%) 95.0 95.0 Spreads (bps) 102.0 - 610.0 604.4 71 Various Total other 380 Total available-for-sale securities $ 1,637 Fair Value Measurements as of June 30, 2017 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Mortgage loans: Single-family $ 509 Build-Up 398 Consensus 51 Various Total single-family 958 Multifamily 161 Build-Up Spreads (bps) 47.0 - 293.2 129.1 Total mortgage loans $ 1,119 Net derivatives $ 121 Dealer Mark 3 Various Total net derivatives $ 124 Long-term debt: Of Fannie Mae: Senior floating $ (365 ) Discounted Cash Flow Of consolidated trusts (3) (543 ) Discounted Cash Flow Default Rate (%) 4.0 - 5.0 4.5 Prepayment Speed (%) 5.0 - 100.0 99.5 Severity (%) 64.0 - 69.0 66.5 Spreads (bps) 43.0 - 656.0 91.6 (217 ) Various Total of consolidated trusts (760 ) Total long-term debt $ (1,125 ) Fair Value Measurements as of December 31, 2016 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Recurring fair value measurements: Trading securities: Mortgage-related securities: Agency (2) $ 809 Consensus 26 Various Total agency 835 Alt-A and subprime private-label securities 232 Consensus Default Rate (%) 0.4 - 10.9 8.2 Prepayment Speed (%) 4.3 - 7.4 6.6 Severity (%) 71.0 - 95.0 88.9 Spreads (bps) 244.6 - 253.9 251.5 39 Consensus Total Alt-A and subprime private-label securities 271 Mortgage revenue bonds 19 Discounted Cash Flow Spreads (bps) 13.0 - 268.2 252.2 2 Various Total mortgage revenue bonds 21 Total trading securities $ 1,127 Available-for-sale securities: Mortgage-related securities: Agency (2) $ 129 Single Vendor Prepayment Speed (%) 124.8 - 165.5 142.4 Spreads (bps) 175.0 - 210.0 182.5 72 Consensus 34 Various Total agency 235 Alt-A and subprime private-label securities 93 Single Vendor Default Rate (%) 2.5 - 8.0 3.8 Prepayment Speed (%) 3.0 - 11.0 4.9 Severity (%) 38.0 - 80.0 48.1 Spreads (bps) 266.1 - 306.8 297.1 45 Discounted Cash Flow Spreads (bps) 361.0 - 450.0 406.0 79 Various Total Alt-A and subprime private-label securities 217 Mortgage revenue bonds 684 Single Vendor Spreads (bps) (16.8 ) - 336.9 44.3 126 Single Vendor 435 Discounted Cash Flow Spreads (bps) (16.8 ) - 391.1 260.0 27 Various Total mortgage revenue bonds 1,272 Other 47 Consensus Default Rate (%) 0.5 - 3.5 3.5 Prepayment Speed (%) 2.5 - 6.0 2.5 Severity (%) 20.0 - 88.0 87.5 Spreads (bps) 221.6 - 300.2 237.7 348 Discounted Cash Flow Default Rate (%) 2.3 2.3 Prepayment Speed (%) 0.5 0.5 Severity (%) 95.0 95.0 Spreads (bps) 190.0 - 450.0 449.1 34 Various Total other 429 Total available-for-sale securities $ 2,153 Fair Value Measurements as of December 31, 2016 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Mortgage loans: Single-family $ 516 Build-Up 300 Consensus 218 Various Total single-family 1,034 Multifamily 163 Build-Up Spreads (bps) 55.0 - 305.2 140.2 Total mortgage loans $ 1,197 Net derivatives $ 10 Internal Model 89 Dealer Mark 21 Discounted Cash Flow (76 ) Various Total net derivatives $ 44 Long-term debt: Of Fannie Mae: Senior floating $ (347 ) Discounted Cash Flow Of consolidated trusts (241 ) Various Total long-term debt $ (588 ) _________ (1) Valuation techniques for which no unobservable inputs are disclosed generally reflect the use of third-party pricing services or dealers, and the range of unobservable inputs applied by these sources is not readily available or cannot be reasonably estimated. Where we have disclosed unobservable inputs for consensus and single vendor techniques, those inputs are based on our validations performed at the security level using discounted cash flows. The prepayment speed used for trading agency securities and available-for-sale agency securities is the Public Securities Association prepayment speed, which can be greater than 100%. For all other securities, the Conditional Prepayment Rate is used as the prepayment speed, which can be between 0% and 100%. (2) Includes Fannie Mae and Freddie Mac securities. (3) Includes instruments for which the prepayment speed represents the estimated annualized rate of prepayment after all prepayment penalty provisions have expired and also instruments for which prepayment speed represents the estimated rate of prepayment over the remaining life of the instrument. In our condensed consolidated balance sheets certain assets and liabilities are measured at fair value on a nonrecurring basis; that is, the instruments are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (for example, when we evaluate loans for impairment). We did not have any Level 1 assets or liabilities held as of June 30, 2017 or December 31, 2016 that were measured at fair value on a nonrecurring basis. We held $814 million and $250 million in Level 2 assets, comprised of mortgage loans held for sale, and no Level 2 liabilities that were measured at fair value on a nonrecurring basis as of June 30, 2017 and December 31, 2016 , respectively. The following table displays valuation techniques for our Level 3 assets measured at fair value on a nonrecurring basis. The significant unobservable inputs related to these techniques primarily relate to collateral dependent valuations. The related ranges and weighted averages are not meaningful when aggregated as they vary significantly from property to property. Fair Value Measurements as of Valuation Techniques June 30, 2017 December 31, 2016 (Dollars in millions) Nonrecurring fair value measurements: Mortgage loans held for sale, at lower of cost or fair value Consensus $ 2,316 $ 1,025 Single Vendor 74 54 Various 2 9 Total mortgage loans held for sale, at lower of cost or fair value 2,392 1,088 Single-family mortgage loans held for investment, at amortized cost Internal Model 1,806 2,816 Multifamily mortgage loans held for investment, at amortized cost Broker Price Opinions 19 25 Asset Manager Estimate 96 170 Various — 3 Total multifamily mortgage loans held for investment, at amortized cost 115 198 Acquired property, net: (1) Single-family Accepted Offers 255 340 Appraisals 509 571 Walk Forwards 200 306 Internal Model 294 476 Various 44 99 Total single-family 1,302 1,792 Multifamily Broker Price Opinions 27 — Other assets Various 2 12 Total nonrecurring assets at fair value $ 5,644 $ 5,906 __________ (1) The most commonly used techniques in our valuation of acquired property are proprietary home price model and third-party valuations (both current and walk forward). Based on the number of properties measured as of June 30, 2017 , these methodologies comprised approximately 74% of our valuations, while accepted offers comprised approximately 20% of our valuations. Based on the number of properties measured as of December 31, 2016, these methodologies comprised approximately 75% of our valuations, while accepted offers comprised approximately 19% of our valuations. We use valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. See “Note 17, Fair Value” in our 2016 Form 10-K for information on the valuation control processes and the valuation techniques we use for fair value measurement and disclosure as well as our basis for classifying these measurements as Level 1, Level 2 or Level 3 of the valuation hierarchy in more specific situations. There were no significant changes made to the valuation control processes and the valuation techniques for the six months ended June 30, 2017. Fair Value of Financial Instruments The following table displays the carrying value and estimated fair value of our financial instruments. The fair value of financial instruments we disclose includes commitments to purchase multifamily and single-family mortgage loans that we do not record in our condensed consolidated balance sheets. The fair values of these commitments are included as “Mortgage loans held for investment, net of allowance for loan losses.” The disclosure excludes all non-financial instruments; therefore, the fair value of our financial assets and liabilities does not represent the underlying fair value of our total consolidated assets and liabilities. As of June 30, 2017 Carrying Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Netting Adjustment Estimated (Dollars in millions) Financial assets: Cash and cash equivalents and restricted cash $ 47,903 $ 36,003 $ 11,900 $ — $ — $ 47,903 Federal funds sold and securities purchased under agreements to resell or similar arrangements 29,220 — 29,220 — — 29,220 Trading securities 39,274 32,418 4,720 2,136 — 39,274 Available-for-sale securities 6,408 — 4,771 1,637 — 6,408 Mortgage loans held for sale 5,322 — 3,193 2,897 — 6,090 Mortgage loans held for investment, net of allowance for loan losses 3,120,093 — 2,828,761 322,070 — 3,150,831 Advances to lenders 4,965 — 4,659 322 — 4,981 Derivative assets at fair value 419 — 4,276 167 (4,024 ) 419 Guaranty assets and buy-ups 148 — — 433 — 433 Total financial assets $ 3,253,752 $ 68,421 $ 2,891,500 $ 329,662 $ (4,024 ) $ 3,285,559 Financial liabilities: Federal funds purchased and securities sold under agreements to repurchase $ 7 $ — $ 7 $ — $ — $ 7 Short-term debt: Of Fannie Mae 30,501 — 30,501 — — 30,501 Of consolidated trusts 511 — — 511 — 511 Long-term debt: Of Fannie Mae 272,619 — 280,471 812 — 281,283 Of consolidated trusts 2,984,036 — 2,954,716 40,513 — 2,995,229 Derivative liabilities at fair value 420 — 5,411 43 (5,034 ) 420 Guaranty obligations 264 — — 523 — 523 Total financial liabilities $ 3,288,358 $ — $ 3,271,106 $ 42,402 $ (5,034 ) $ 3,308,474 As of December 31, 2016 Carrying Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Netting Adjustment Estimated (Dollars in millions) Financial assets: Cash and cash equivalents and restricted cash $ 62,177 $ 41,477 $ 20,700 $ — $ — $ 62,177 Federal funds sold and securities purchased under agreements to resell or similar arrangements 30,415 — 30,415 — — 30,415 Trading securities 40,562 32,317 7,118 1,127 — 40,562 Available-for-sale securities 8,363 — 6,210 2,153 — 8,363 Mortgage loans held for sale 2,899 — 509 2,751 — 3,260 Mortgage loans held for investment, net of allowance for loan losses 3,076,854 — 2,767,813 316,742 — 3,084,555 Advances to lenders 7,494 — 7,156 352 — 7,508 Derivative assets at fair value 687 — 5,019 182 (4,514 ) 687 Guaranty assets and buy-ups 158 — — 432 — 432 Total financial assets $ 3,229,609 $ 73,794 $ 2,844,940 $ 323,739 $ (4,514 ) $ 3,237,959 Financial liabilities: Short-term debt: Of Fannie Mae $ 34,995 $ — $ 34,998 $ — $ — $ 34,998 Of consolidated trusts 584 — — 584 — 584 Long-term debt: Of Fannie Mae 292,102 — 298,980 770 — 299,750 Of consolidated trusts 2,934,635 — 2,901,316 36,668 — 2,937,984 Derivative liabilities at fair value 1,215 — 7,921 138 (6,844 ) 1,215 Guaranty obligations 280 — — 710 — 710 Total financial liabilities $ 3,263,811 $ — $ 3,243,215 $ 38,870 $ (6,844 ) $ 3,275,241 For a detailed description and classification of our financial instruments, see “Note 17, Fair Value” in our 2016 Form 10-K. Fair Value Option We elected the fair value option for our credit risk sharing debt securities issued under our CAS series issued prior to January 1, 2016 and certain loans that contain embedded derivatives that would otherwise require bifurcation. Under the fair value option, we elected to carry these instruments at fair value instead of bifurcating the embedded derivative from such instruments. We elected the fair value option for all long-term structured debt instruments that are issued in response to specific investor demand and have interest rates that are based on a calculated index or formula and are economically hedged with derivatives at the time of issuance. By electing the fair value option for these instruments, we are able to eliminate the volatility in our results of operations that would otherwise result from the accounting asymmetry created by recording these structured debt instruments at cost while recording the related derivatives at fair value. We elected the fair value option for the financial assets and liabilities of the consolidated senior-subordinate trust structures. By electing the fair value option for these instruments, we are able to eliminate the volatility in our results of operations that would otherwise result from different accounting treatment between loans at cost and debt at cost. Interest income for the mortgage loans is recorded in “Interest income—Mortgage loans” and interest expense for the debt instruments is recorded in “Interest expense—Long-term debt” in our condensed consolidated statements of operations and comprehensive income. The following table displays the fair value and unpaid principal balance of the financial instruments for which we have made fair value elections. As of June 30, 2017 December 31, 2016 Loans (1) Long-Term Debt of Fannie Mae Long-Term Debt of Consolidated Trusts Loans (1) Long-Term Debt of Fannie Mae Long-Term Debt of Consolidated Trusts (Dollars in millions) Fair value $ 11,406 $ 9,008 $ 34,866 $ 12,057 $ 9,582 $ 36,524 Unpaid principal balance 10,980 8,167 31,510 11,688 9,090 33,055 __________ (1) Includes nonaccrual loans with a fair value of $187 million and $200 million as of June 30, 2017 and December 31, 2016 , respectively. The difference between unpaid principal balance and the fair value of these nonaccrual loans as of June 30, 2017 and December 31, 2016 was $33 million and $34 million , respectively. Includes loans that are 90 days or more past due with a fair value of $145 million and $152 million as of June 30, 2017 and December 31, 2016 , respectively. The difference between unpaid principal balance and the fair value of these 90 or more days past due loans as of June 30, 2017 and December 31, 2016 was $25 million . Changes in Fair Value under the Fair Value Option Election The following tables display fair value gains and losses, net, including changes attributable to instrument-specific credit risk, for loans and debt for which the fair value election was made. Amounts are recorded as a component of “ Fair value losses, net ” in our condensed consolidated statements of operations and comprehensive income. For the Three Months Ended June 30, 2017 2016 Loans Long-Term Debt Total Gains (Losses) Loans Long-Term Debt Total Gains (Losses) (Dollars in millions) Changes in instrument-specific credit risk $ 26 $ (173 ) $ (147 ) $ 19 $ (169 ) $ (150 ) Other changes in fair value 68 (115 ) (47 ) 126 (144 ) (18 ) Fair value gains (losses), net $ 94 $ (288 ) $ (194 ) $ 145 $ (313 ) $ (168 ) For the Six Months Ended June 30, 2017 2016 Loans Long-Term Debt Total Gains (Losses) Loans Long-Term Debt Total Gains (Losses) (Dollars in millions) Changes in instrument-specific credit risk $ 53 $ (339 ) $ (286 ) $ 32 $ (221 ) $ (189 ) Other changes in fair value 83 (118 ) (35 ) 344 (446 ) (102 ) Fair value gains (losses), net $ 136 $ (457 ) $ (321 ) $ 376 $ (667 ) $ (291 ) In determining the changes in the instrument-specific credit risk for loans, the changes in the associated credit-related components of these loans, primarily the guaranty obligation, were taken into consideration with the change in the fair value of the loans for which we elected the fair value option for financial instruments. In determining the changes in the instrument-specific credit risk for debt, the changes in Fannie Mae debt spreads to LIBOR that occurred during the period were taken into consideration with the change in the fair value of the debt for which we elected the fair value option for financial instruments. Specifically, cash flows are evaluated taking into consideration any derivatives through which Fannie Mae has swapped out of the structured features of the notes and thus created a floating-rate LIBOR-based debt instrument. The change in value of these LIBOR-based cash flows based on the Fannie Mae yield curve at the beginning and end of the period represents the instrument-specific credit risk.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies We are party to various types of legal actions and proceedings, including actions brought on behalf of various classes of claimants. We also are subject to regulatory examinations, inquiries and investigations, and other information gathering requests. In some of the matters, indeterminate amounts are sought. Modern pleading practice in the U.S. permits considerable variation in the assertion of monetary damages or other relief. Jurisdictions may permit claimants not to specify the monetary damages sought or may permit claimants to state only that the amount sought is sufficient to invoke the jurisdiction of the trial court. This variability in pleadings, together with our and our counsel’s actual experience in litigating or settling claims, leads us to conclude that the monetary relief that may be sought by plaintiffs bears little relevance to the merits or disposition value of claims. On a quarterly basis, we review relevant information about all pending legal actions and proceedings for the purpose of evaluating and revising our contingencies, accruals and disclosures. We have substantial and valid defenses to the claims in the proceedings described below and intend to defend these matters vigorously. However, legal actions and proceedings of all types are subject to many uncertain factors that generally cannot be predicted with assurance. Accordingly, the outcome of any given matter and the amount or range of potential loss at particular points in time is frequently difficult to ascertain. Uncertainties can include how fact finders will evaluate documentary evidence and the credibility and effectiveness of witness testimony, and how courts will apply the law. Disposition valuations are also subject to the uncertainty of how opposing parties and their counsel may view the evidence and applicable law. We establish an accrual for matters when a loss is probable and we can reasonably estimate the amount of such loss. For legal actions or proceedings where there is only a reasonable possibility that a loss may be incurred, or where we are not currently able to estimate the reasonably possible loss or range of loss, we do not establish an accrual. We are often unable to estimate the possible losses or ranges of losses, particularly for proceedings that are in their early stages of development, where plaintiffs seek indeterminate or unspecified damages, where there may be novel or unsettled legal questions relevant to the proceedings, or where settlement negotiations have not occurred or progressed. Given the uncertainties involved in any action or proceeding, regardless of whether we have established an accrual, the ultimate resolution of certain of these matters may be material to our operating results for a particular period, depending on, among other factors, the size of the loss or liability imposed and the level of our net income or loss for that period. In addition to the matters specifically described below, we are involved in a number of legal and regulatory proceedings that arise in the ordinary course of business that we do not expect will have a material impact on our business or financial condition. We have also advanced fees and expenses of certain current and former officers and directors in connection with various legal proceedings pursuant to our bylaws and indemnification agreements. Senior Preferred Stock Purchase Agreements Litigation A number of putative class action lawsuits were filed in the U.S. District Court for the District of Columbia against us, FHFA as our conservator, Treasury and Freddie Mac from July through September 2013 by shareholders of Fannie Mae and/or Freddie Mac challenging the August 2012 amendment to each company’s senior preferred stock purchase agreement with Treasury. These lawsuits were consolidated and, on December 3, 2013, plaintiffs (preferred and common shareholders of Fannie Mae and/or Freddie Mac) filed a consolidated class action complaint in the U.S. District Court for the District of Columbia against us, FHFA as our conservator, Treasury and Freddie Mac (“ In re Fannie Mae/Freddie Mac Senior Preferred Stock Purchase Agreement Class Action Litigations ”). The preferred shareholder plaintiffs allege that the net worth sweep dividend provisions of the senior preferred stock that were implemented pursuant to the August 2012 amendments to the senior preferred stock purchase agreements nullified certain of the shareholders’ rights, particularly the right to receive dividends. The common shareholder plaintiffs allege that the August 2012 amendments constituted a taking of their property by requiring that all future profits of Fannie Mae and Freddie Mac be paid to Treasury. Plaintiffs allege claims for breach of contract and breach of the implied covenant of good faith and fair dealing against us, FHFA and Freddie Mac, a takings claim against FHFA and Treasury, and a breach of fiduciary duty claim derivatively on our and Freddie Mac’s behalf against FHFA and Treasury. Plaintiffs seek to represent several classes of preferred and/or common shareholders of Fannie Mae and/or Freddie Mac who held stock as of the public announcement of the August 2012 amendments. Plaintiffs seek unspecified damages, equitable and injunctive relief, and costs and expenses, including attorneys’ fees. A non-class action suit, Arrowood Indemnity Company v. Fannie Mae , was filed in the U.S. District Court for the District of Columbia on September 20, 2013 by preferred shareholders against us, FHFA as our conservator, the Director of FHFA (in his official capacity), Treasury, the Secretary of the Treasury (in his official capacity) and Freddie Mac. Plaintiffs bring claims for breach of contract and breach of the implied covenant of good faith and fair dealing against us, FHFA and Freddie Mac, and claims for violation of the Administrative Procedure Act against the FHFA and Treasury defendants, alleging that the net worth sweep dividend provisions nullified certain rights of the preferred shareholders, particularly the right to receive dividends. Plaintiffs seek damages, equitable and injunctive relief, and costs and expenses, including attorneys’ fees. On September 30, 2014, the court dismissed both lawsuits and plaintiffs in both suits filed timely notices of appeal. On February 21, 2017, the U.S. Court of Appeals for the D.C. Circuit affirmed the district court’s dismissal of the claims alleging violation of the Administrative Procedure Act, but reversed the district court’s dismissal of the claims alleging breach of the implied covenant of good faith and fair dealing and one of the breach of contract claims . The court also ruled that the class-action plaintiffs could seek leave in the district court to amend their claim for breach of fiduciary duty from a derivative to a direct claim. On July 17, 2017, the Court of Appeals issued a revised opinion allowing certain plaintiffs to continue to maintain their breach of the implied covenant of good faith and fair dealing and breach of contract claims that the original opinion had found not properly preserved, and modifying its discussion of the standard that applies to the breach of implied covenant claim. Given the stage of these lawsuits, the substantial and novel legal questions that remain, and our substantial defenses, we are currently unable to estimate the reasonably possible loss or range of loss arising from this litigation.

Subsequent Events (Notes)

Subsequent Events (Notes)	6 Months Ended
	Jun. 30, 2017
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On July 12, 2017, FHFA, the conservator, on behalf of Fannie Mae and Freddie Mac, entered into a settlement agreement with The Royal Bank of Scotland Group plc and certain related entities and individuals (collectively “RBS”) resolving legal claims relating to private-label mortgage-backed securities RBS sold to Fannie Mae and Freddie Mac. As a result of this settlement, we will recognize approximately $975 million in “Fee and other income” in our condensed consolidated statements of operations and comprehensive income for the three months ended September 30, 2017.

Summary of Significant Accoun23

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Basis of Presentation [Policy Text Block]	Basis of Presentation The accompanying unaudited interim condensed consolidated financial statements have been prepared in accordance with GAAP for interim financial information and with the SEC’s instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and note disclosures required by GAAP for complete consolidated financial statements. In the opinion of management, all adjustments of a normal recurring nature considered necessary for a fair presentation have been included. The accompanying condensed consolidated financial statements include our accounts as well as the accounts of other entities in which we have a controlling financial interest. All intercompany accounts and transactions have been eliminated. To conform to our current period presentation, we have reclassified certain amounts reported in our prior periods’ condensed consolidated financial statements. Results for the six months ended June 30, 2017 may not necessarily be indicative of the results for the year ending December 31, 2017 . The unaudited interim condensed consolidated financial statements as of and for the six months ended June 30, 2017 should be read in conjunction with our audited consolidated financial statements and related notes included in our annual report on Form 10-K for the year ended December 31, 2016 (“ 2016 Form 10-K”), filed with the SEC on February 17, 2017 .
Use of Estimates, Policy [Policy Text Block]	Use of Estimates Preparing condensed consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that affect our reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities as of the dates of our condensed consolidated financial statements, as well as our reported amounts of revenues and expenses during the reporting periods. Management has made significant estimates in a variety of areas including, but not limited to, valuation of certain financial instruments, other assets and liabilities, and allowance for loan losses. Actual results could be different from these estimates.
New Accounting Pronouncements, Policy [Policy Text Block]	New Accounting Guidance In June 2016, the Financial Accounting Standards Board (“FASB”) issued guidance that changes the impairment model for most financial assets and certain other instruments. For loans, held-to-maturity debt securities and other financial assets recorded at amortized cost, entities will be required to use a new forward-looking “expected loss” model that will replace today’s “incurred loss” model and generally will result in the earlier recognition of allowance for loan losses. The guidance is effective on January 1, 2020 with early adoption permitted on January 1, 2019. We will recognize the impact of the new guidance through a cumulative effect adjustment to retained earnings as of the beginning of the year of adoption. We are continuing to evaluate the impact of this guidance on our condensed consolidated financial statements, including the timing of the adoption. We expect the greater impact of the guidance to relate to our accounting for credit losses for loans that are not individually impaired. The adoption of this guidance will decrease, perhaps substantially, our retained earnings and increase our allowance for loan losses.

Consolidations and Transfers 24

Consolidations and Transfers of Financial Assets (Policies)	6 Months Ended
	Jun. 30, 2017
Consolidations and Transfers of Financial Assets [Abstract]
Consolidations, Policy [Policy Text Block]	We have interests in various entities that are considered to be VIEs. The primary types of entities are securitization trusts and limited partnerships. These interests include investments in securities issued by VIEs, such as Fannie Mae MBS created pursuant to our securitization transactions and our guaranty to the entity. We consolidate the substantial majority of our single-class securitization trusts because our role as guarantor and master servicer provides us with the power to direct matters (primarily the servicing of mortgage loans) that impact the credit risk to which we are exposed. In contrast, we do not consolidate single-class securitization trusts when other organizations have the power to direct these activities. Unconsolidated VIEs We do not consolidate VIEs when we are not deemed to be the primary beneficiary. Our unconsolidated VIEs include securitization trusts and limited partnerships.
Transfers and Servicing of Financial Assets, Policy [Policy Text Block]	Transfers of Financial Assets We issue Fannie Mae MBS through portfolio securitization transactions by transferring pools of mortgage loans or mortgage-related securities to one or more trusts or special purpose entities. We are considered to be the transferor when we transfer assets from our own retained mortgage portfolio in a portfolio securitization transaction.

Mortgage Loans (Policies)

Mortgage Loans (Policies)	6 Months Ended
	Jun. 30, 2017
Mortgage Loans on Real Estate [Abstract]
Finance, Loan and Lease Receivables, Held-for-investment, Policy [Policy Text Block]	We define the recorded investment of HFI loans as unpaid principal balance, net of unamortized premiums and discounts, other cost basis adjustments, and accrued interest receivable. We report the carrying value of HFI loans at the unpaid principal balance, net of unamortized premiums and discounts, other cost basis adjustments, and an allowance for loan losses.
Finance, Loan and Lease Receivables, Held-for-sale, Policy [Policy Text Block]	We report the carrying value of HFS loans at the lower of cost or fair value and record valuation changes in “Investment gains, net” in our condensed consolidated statements of operations and comprehensive income.
Nonaccrual Loans [Policy Text Block]	We discontinue accruing interest on loans when we believe collectibility of principal or interest is not reasonably assured, which for a single-family loan we have determined, based on our historical experience, to be when the loan becomes two months or more past due according to its contractual terms. Interest previously accrued but not collected is reversed through interest income at the date a loan is placed on nonaccrual status. We return a nonmodified single-family loan to accrual status at the point that the borrower brings the loan current. We return a modified single-family loan to accrual status at the point that the borrower successfully makes all required payments during the trial period (generally three to four months) and the modification is made permanent. We place a multifamily loan on nonaccrual status when the loan becomes three months or more past due according to its contractual terms or is deemed to be individually impaired, unless the loan is well secured such that collectibility of principal and accrued interest is reasonably assured. We return a multifamily loan to accrual status when the borrower cures the delinquency of the loan or we otherwise determine that the loan is well secured such that collectibility is reasonably assured.
Troubled Debt Restructurings [Policy Text Block]	A modification to the contractual terms of a loan that results in granting a concession to a borrower experiencing financial difficulties is considered a TDR.

Allowance for Loan Losses (Poli

Allowance for Loan Losses (Policies)	6 Months Ended
	Jun. 30, 2017
Receivables [Abstract]
Allowance for Loan Losses [Policy Text Block]	We maintain an allowance for loan losses for HFI loans held by Fannie Mae and loans backing Fannie Mae MBS issued from consolidated trusts. When calculating our allowance for loan losses, we consider our net carrying value of HFI loans at the balance sheet date, which includes unpaid principal balance, net of amortized premiums and discounts, and other cost basis adjustments. We record charge-offs as a reduction to our allowance for loan losses at the point of foreclosure, completion of a short sale, upon the redesignation of loans from HFI to HFS or when a loan is determined to be uncollectible. We aggregate single-family HFI loans that are not individually impaired based on similar risk characteristics for purposes of estimating incurred credit losses and establishing a collective single-family loss reserve using an econometric model that derives an overall loss reserve estimate. We base our allowance methodology on historical events and trends, such as loss severity (in event of default), default rates, and recoveries from mortgage insurance contracts and other credit enhancements that provide loan level loss coverage and are either contractually attached to a loan or that were entered into contemporaneously with and in contemplation of a guaranty or loan purchase transaction. We use recent regional historical sales and appraisal information including the sales of our own foreclosed properties, to develop our loss severity estimates for all loan categories. Our allowance calculation also incorporates a loss confirmation period (the anticipated time lag between a credit loss event and the confirmation of the credit loss resulting from that event) to ensure our allowance estimate captures credit losses that have been incurred as of the balance sheet date but have not been confirmed. In addition, management performs a review of the observable data used in its estimate to ensure it is representative of prevailing economic conditions and other events existing as of the balance sheet date. Individually impaired single-family loans currently include those restructured in a TDR and acquired credit-impaired loans. We consider a loan to be impaired when, based on current information, it is probable that we will not receive all amounts due, including interest, in accordance with the contractual terms of the loan agreement. When a loan has been restructured, we measure impairment using a cash flow analysis discounted at the loan’s original effective interest rate. If we expect to recover our recorded investment in an individually impaired loan through probable foreclosure of the underlying collateral, we measure impairment based on the fair value of the collateral, reduced by estimated disposal costs and adjusted for estimated proceeds from mortgage, flood, or hazard insurance or similar sources. We establish a collective allowance for all loans in our multifamily guaranty book of business that are not individually impaired using an internal model that applies loss factors to loans in similar risk categories. Our loss factors are developed based on our historical default and loss severity experience. We identify multifamily loans for evaluation for impairment through a credit risk assessment process. If we determine that a multifamily loan is individually impaired, we generally measure impairment on that loan based on the fair value of the underlying collateral less estimated costs to sell the property, as we have concluded that such loans are collateral dependent. We evaluate collectively for impairment smaller-balance homogeneous multifamily loans.

Investment in Securities (Polic

Investment in Securities (Policies)	6 Months Ended
	Jun. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Trading Securities, Policy [Policy Text Block]	Trading Securities Trading securities are recorded at fair value with subsequent changes in fair value recorded as “ Fair value losses, net ” in our condensed consolidated statements of operations and comprehensive income.
Available-for-sale Securities, Policy [Policy Text Block]	Available-for-Sale Securities We record available-for-sale (“AFS”) securities at fair value with unrealized gains and losses, recorded net of tax, as a component of “Other comprehensive income (loss)” and we recognize realized gains and losses from the sale of AFS securities in “ Investment gains, net ” in our condensed consolidated statements of operations and comprehensive income.

Derivative Instruments (Policie

Derivative Instruments (Policies)	6 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives, Policy [Policy Text Block]	We recognize all derivatives as either assets or liabilities in our condensed consolidated balance sheets at their fair value on a trade date basis. Fair value amounts, which are netted to the extent a legal right of offset exists and is enforceable by law at the counterparty level and are inclusive of the right or obligation associated with the cash collateral posted or received, are recorded in “Other assets” or “Other liabilities” in our condensed consolidated balance sheets. See “ Note 14, Fair Value ” for additional information on derivatives recorded at fair value. We present cash flows from derivatives as operating activities in our condensed consolidated statements of cash flows.

Segment Reporting (Policies)

Segment Reporting (Policies)	6 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
Segment Reporting, Policy [Policy Text Block]	We have two reportable business segments: Single-Family and Multifamily. Previously, we had a third reportable business segment, Capital Markets, which was incorporated into the Single-Family and Multifamily segments in the fourth quarter of 2016. Results of our two business segments are intended to reflect each segment as if it were a stand-alone business. We have revised the presentation of our segment results for the prior periods to be consistent with the current period presentation.

Netting Arrangements (Policies)

Netting Arrangements (Policies)	6 Months Ended
	Jun. 30, 2017
Offsetting [Abstract]
Derivatives, Offsetting Policy [Policy Text Block]	Derivative instruments are recorded at fair value and securities purchased under agreements to resell or similar arrangements are recorded at amortized cost in our condensed consolidated balance sheets. We determine our rights to offset the assets and liabilities presented above with the same counterparty, including collateral posted or received, based on the contractual arrangements entered into with our individual counterparties and various rules and regulations that would govern the insolvency of a derivative counterparty.

Fair Value (Policies)

Fair Value (Policies)	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurement, Policy [Policy Text Block]	Fair Value Measurement Fair value measurement guidance defines fair value, establishes a framework for measuring fair value, and sets forth disclosures around fair value measurements. This guidance applies whenever other accounting guidance requires or permits assets or liabilities to be measured at fair value. The guidance establishes a three-level fair value hierarchy that prioritizes the inputs into the valuation techniques used to measure fair value. The fair value hierarchy gives the highest priority, Level 1, to measurements based on unadjusted quoted prices in active markets for identical assets or liabilities. The next highest priority, Level 2, is given to measurements of assets and liabilities based on limited observable inputs or observable inputs for similar assets and liabilities. The lowest priority, Level 3, is given to measurements based on unobservable inputs. Fair Value Option We elected the fair value option for our credit risk sharing debt securities issued under our CAS series issued prior to January 1, 2016 and certain loans that contain embedded derivatives that would otherwise require bifurcation. Under the fair value option, we elected to carry these instruments at fair value instead of bifurcating the embedded derivative from such instruments. We elected the fair value option for all long-term structured debt instruments that are issued in response to specific investor demand and have interest rates that are based on a calculated index or formula and are economically hedged with derivatives at the time of issuance. By electing the fair value option for these instruments, we are able to eliminate the volatility in our results of operations that would otherwise result from the accounting asymmetry created by recording these structured debt instruments at cost while recording the related derivatives at fair value. We elected the fair value option for the financial assets and liabilities of the consolidated senior-subordinate trust structures. By electing the fair value option for these instruments, we are able to eliminate the volatility in our results of operations that would otherwise result from different accounting treatment between loans at cost and debt at cost. Interest income for the mortgage loans is recorded in “Interest income—Mortgage loans” and interest expense for the debt instruments is recorded in “Interest expense—Long-term debt” in our condensed consolidated statements of operations and comprehensive income.

Commitments and Contingencies (

Commitments and Contingencies (Policies)	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies, Policy [Policy Text Block]	We establish an accrual for matters when a loss is probable and we can reasonably estimate the amount of such loss. For legal actions or proceedings where there is only a reasonable possibility that a loss may be incurred, or where we are not currently able to estimate the reasonably possible loss or range of loss, we do not establish an accrual. On a quarterly basis, we review relevant information about all pending legal actions and proceedings for the purpose of evaluating and revising our contingencies, accruals and disclosures.

Consolidations and Transfers 33

Consolidations and Transfers of Financial Assets (Tables)	6 Months Ended
	Jun. 30, 2017
Consolidations and Transfers of Financial Assets [Abstract]
Unconsolidated Variable Interest Entities [Table Text Block]	The following table displays the carrying amount and classification of our assets and liabilities that relate to our involvement with unconsolidated securitization trusts. As of June 30, 2017 December 31, 2016 (Dollars in millions) Assets: Trading securities: Fannie Mae $ 4,197 $ 4,642 Non-Fannie Mae 2,577 3,473 Total trading securities 6,774 8,115 Available-for-sale securities: Fannie Mae 2,174 2,447 Non-Fannie Mae 3,319 4,879 Total available-for-sale securities 5,493 7,326 Other assets 74 77 Other liabilities (501 ) (528 ) Net carrying amount $ 11,840 $ 14,990

Mortgage Loans (Tables)

Mortgage Loans (Tables)	6 Months Ended
	Jun. 30, 2017
Mortgage Loans on Real Estate [Line Items]
Loans in Mortgage Portfolio [Table Text Block]	The following table displays the carrying value of our mortgage loans. As of June 30, 2017 December 31, 2016 (Dollars in millions) Single-family $ 2,861,253 $ 2,833,750 Multifamily 244,701 229,896 Total unpaid principal balance of mortgage loans 3,105,954 3,063,646 Cost basis and fair value adjustments, net 39,860 39,572 Allowance for loan losses for loans held for investment (20,399 ) (23,465 ) Total mortgage loans $ 3,125,415 $ 3,079,753 The following table displays the allowance for loan losses and recorded investment in our HFI loans, excluding loans for which we have elected the fair value option, by impairment or allowance methodology and portfolio segment. As of June 30, 2017 December 31, 2016 Single-Family Multifamily Total Single-Family Multifamily Total (Dollars in millions) Allowance for loan losses by segment: Individually impaired loans (1) $ 19,197 $ 41 $ 19,238 $ 21,920 $ 33 $ 21,953 Collectively reserved loans 1,021 140 1,161 1,363 149 1,512 Total allowance for loan losses $ 20,218 $ 181 $ 20,399 $ 23,283 $ 182 $ 23,465 Recorded investment in loans by segment: Individually impaired loans (1) $ 144,833 $ 487 $ 145,320 $ 155,598 $ 589 $ 156,187 Collectively reserved loans 2,745,268 246,141 2,991,409 2,708,337 231,292 2,939,629 Total recorded investment in loans $ 2,890,101 $ 246,628 $ 3,136,729 $ 2,863,935 $ 231,881 $ 3,095,816 __________ (1) Includes acquired credit-impaired loans.
Aging Analysis [Table Text Block]	The following tables display an aging analysis of the total recorded investment in our HFI mortgage loans by portfolio segment and class, excluding loans for which we have elected the fair value option. As of June 30, 2017 30 - 59 Days Delinquent 60 - 89 Days Delinquent Seriously Delinquent (1) Total Delinquent Current Total Recorded Investment in Loans 90 Days or More Delinquent and Accruing Interest Recorded Investment in Nonaccrual Loans (Dollars in millions) Single-family: Primary $ 27,294 $ 6,677 $ 17,842 $ 51,813 $ 2,703,162 $ 2,754,975 $ 19 $ 28,056 Government (2) 50 21 229 300 35,080 35,380 228 1 Alt-A 3,103 1,000 3,451 7,554 66,845 74,399 2 5,026 Other 1,141 367 1,259 2,767 22,580 25,347 4 1,827 Total single-family 31,588 8,065 22,781 62,434 2,827,667 2,890,101 253 34,910 Multifamily (3) 27 N/A 95 122 246,506 246,628 — 341 Total $ 31,615 $ 8,065 $ 22,876 $ 62,556 $ 3,074,173 $ 3,136,729 $ 253 $ 35,251 As of December 31, 2016 30 - 59 Days Delinquent 60 - 89 Days Delinquent Seriously Delinquent (1) Total Delinquent Current Total Recorded Investment in Loans 90 Days or More Delinquent and Accruing Interest Recorded Investment in Nonaccrual Loans (Dollars in millions) Single-family: Primary $ 31,631 $ 7,910 $ 21,761 $ 61,302 $ 2,654,195 $ 2,715,497 $ 22 $ 33,448 Government (2) 56 22 256 334 36,814 37,148 256 — Alt-A 3,629 1,194 4,221 9,044 72,903 81,947 2 6,019 Other 1,349 438 1,582 3,369 25,974 29,343 5 2,238 Total single-family 36,665 9,564 27,820 74,049 2,789,886 2,863,935 285 41,705 Multifamily (3) 44 N/A 129 173 231,708 231,881 — 403 Total $ 36,709 $ 9,564 $ 27,949 $ 74,222 $ 3,021,594 $ 3,095,816 $ 285 $ 42,108 __________ (1) Single-family seriously delinquent loans are loans that are 90 days or more past due or in the foreclosure process. Multifamily seriously delinquent loans are loans that are 60 days or more past due. (2) Primarily consists of reverse mortgages, which due to their nature, are not aged and are included in the current column. (3) Multifamily loans 60 - 89 days delinquent are included in the seriously delinquent column.
Individually Impaired Loans [Table Text Block]	The following tables display the total unpaid principal balance, recorded investment, related allowance, average recorded investment and interest income recognized for individually impaired loans. As of June 30, 2017 December 31, 2016 Unpaid Principal Balance Total Recorded Investment Related Allowance for Loan Losses Unpaid Principal Balance Total Recorded Investment Related Allowance for Loan Losses (Dollars in millions) Individually impaired loans: With related allowance recorded: Single-family: Primary $ 97,394 $ 92,591 $ 12,778 $ 105,113 $ 99,825 $ 14,462 Government 288 291 58 302 305 59 Alt-A 25,862 23,556 4,642 28,599 26,059 5,365 Other 9,651 9,106 1,719 11,087 10,465 2,034 Total single-family 133,195 125,544 19,197 145,101 136,654 21,920 Multifamily 217 218 41 320 323 33 Total individually impaired loans with related allowance recorded 133,412 125,762 19,238 145,421 136,977 21,953 With no related allowance recorded: (1) Single-family: Primary 16,109 15,225 — 15,733 14,758 — Government 67 62 — 63 59 — Alt-A 3,418 3,010 — 3,511 3,062 — Other 1,078 992 — 1,159 1,065 — Total single-family 20,672 19,289 — 20,466 18,944 — Multifamily 268 269 — 266 266 — Total individually impaired loans with no related allowance recorded 20,940 19,558 — 20,732 19,210 — Total individually impaired loans (2) $ 154,352 $ 145,320 $ 19,238 $ 166,153 $ 156,187 $ 21,953 For the Three Months Ended June 30, 2017 2016 Average Recorded Investment Total Interest Income Recognized (3) Interest Income Recognized on a Cash Basis Average Recorded Investment Total Interest Income Recognized (3) Interest Income Recognized on a Cash Basis (Dollars in millions) Individually impaired loans: With related allowance recorded: Single-family: Primary $ 94,599 $ 955 $ 77 $ 106,674 $ 1,015 $ 71 Government 295 2 — 317 3 — Alt-A 24,249 240 14 27,901 256 11 Other 9,419 82 5 11,639 93 3 Total single-family 128,562 1,279 96 146,531 1,367 85 Multifamily 259 4 — 556 13 — Total individually impaired loans with related allowance recorded 128,821 1,283 96 147,087 1,380 85 With no related allowance recorded: (1) Single-family: Primary 15,091 273 24 15,377 327 30 Government 61 1 — 59 1 — Alt-A 3,026 67 2 3,361 81 5 Other 1,016 21 1 1,126 30 2 Total single-family 19,194 362 27 19,923 439 37 Multifamily 284 7 — 326 3 — Total individually impaired loans with no related allowance recorded 19,478 369 27 20,249 442 37 Total individually impaired loans $ 148,299 $ 1,652 $ 123 $ 167,336 $ 1,822 $ 122 For the Six Months Ended June 30, 2017 2016 Average Recorded Investment Total Interest Income Recognized (3) Interest Income Recognized on a Cash Basis Average Recorded Investment Total Interest Income Recognized (3) Interest Income Recognized on a Cash Basis (Dollars in millions) Individually impaired loans: With related allowance recorded: Single-family: Primary $ 96,395 $ 1,941 $ 165 $ 107,984 $ 2,036 $ 175 Government 298 5 — 320 6 — Alt-A 24,896 489 29 28,287 509 30 Other 9,805 169 10 11,827 185 11 Total single-family 131,394 2,604 204 148,418 2,736 216 Multifamily 280 6 — 589 18 — Total individually impaired loans with related allowance recorded 131,674 2,610 204 149,007 2,754 216 With no related allowance recorded: (1) Single-family: Primary 15,050 562 47 15,323 595 50 Government 61 2 — 58 2 — Alt-A 3,056 140 5 3,362 143 8 Other 1,041 44 2 1,131 52 3 Total single-family 19,208 748 54 19,874 792 61 Multifamily 278 10 — 335 6 — Total individually impaired loans with no related allowance recorded 19,486 758 54 20,209 798 61 Total individually impaired loans $ 151,160 $ 3,368 $ 258 $ 169,216 $ 3,552 $ 277 __________ (1) The discounted cash flows or collateral value equals or exceeds the carrying value of the loan and, as such, no valuation allowance is required. (2) Includes single-family loans restructured in a TDR with a recorded investment of $144.3 billion and $155.0 billion as of June 30, 2017 and December 31, 2016 , respectively. Includes multifamily loans restructured in a TDR with a recorded investment of $198 million and $248 million as of June 30, 2017 and December 31, 2016 , respectively. (3) Total single-family interest income recognized of $1.7 billion for the three months ended June 30, 2017 consists of $1.5 billion of contractual interest and $229 million of effective yield adjustments. Total single-family interest income recognized of $1.8 billion for the three months ended June 30, 2016 consists of $1.5 billion of contractual interest and $331 million of effective yield adjustments. Total single-family interest income recognized of $3.4 billion for the six months ended June 30, 2017 consists of $2.9 billion of contractual interest and $497 million of effective yield adjustments. Total single-family interest income recognized of $3.5 billion for the six months ended June 30, 2016 consists of $2.9 billion of contractual interest and $641 million of effective yield adjustments.
Troubled Debt Restructurings Activity [Table Text Block]	The following tables display the number of loans and recorded investment in loans restructured in a TDR. For the Three Months Ended June 30, 2017 2016 Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 14,148 $ 1,945 14,814 $ 2,028 Government 45 4 28 3 Alt-A 1,328 194 1,623 238 Other 271 46 362 61 Total single-family 15,792 2,189 16,827 2,330 Multifamily 3 17 4 45 Total TDRs 15,795 $ 2,206 16,831 $ 2,375 For the Six Months Ended June 30, 2017 2016 Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 31,383 $ 4,308 32,004 $ 4,360 Government 106 10 82 9 Alt-A 2,893 418 3,534 508 Other 580 99 761 133 Total single-family 34,962 4,835 36,381 5,010 Multifamily 3 17 4 45 Total TDRs 34,965 $ 4,852 36,385 $ 5,055 The following tables display the number of loans and our recorded investment in these loans at the time of payment default for loans that were restructured in a TDR in the twelve months prior to the payment default. For purposes of this disclosure, we define loans that had a payment default as: single-family and multifamily loans with completed TDRs that liquidated during the period, either through foreclosure, deed-in-lieu of foreclosure, or a short sale; single-family loans with completed modifications that are two or more months delinquent during the period; or multifamily loans with completed modifications that are one or more months delinquent during the period. For the Three Months Ended June 30, 2017 2016 Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 4,238 $ 589 4,648 $ 638 Government 25 3 27 3 Alt-A 616 97 756 116 Other 150 30 289 40 Total TDRs that subsequently defaulted 5,029 $ 719 5,720 $ 797 For the Six Months Ended June 30, 2017 2016 Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 8,717 $ 1,210 10,109 $ 1,440 Government 44 5 42 5 Alt-A 1,230 193 1,608 260 Other 351 68 532 89 Total single-family 10,342 1,476 12,291 1,794 Multifamily 1 4 — — Total TDRs that subsequently defaulted 10,343 $ 1,480 12,291 $ 1,794
Single-family [Member]
Mortgage Loans on Real Estate [Line Items]
Credit Quality Indicators [Table Text Block]	The following table displays the total recorded investment in our single-family HFI loans by class and credit quality indicator, excluding loans for which we have elected the fair value option. As of June 30, 2017 (1) December 31, 2016 (1) Primary Alt-A Other Primary Alt-A Other (Dollars in millions) Estimated mark-to-market loan-to-value (“LTV”) ratio: (2) Less than or equal to 80% $ 2,410,185 $ 54,917 $ 18,219 $ 2,321,201 $ 56,250 $ 19,382 Greater than 80% and less than or equal to 90% 231,412 8,010 2,826 244,231 9,787 3,657 Greater than 90% and less than or equal to 100% 88,637 5,088 1,908 114,412 6,731 2,627 Greater than 100% 24,741 6,384 2,394 35,653 9,179 3,677 Total $ 2,754,975 $ 74,399 $ 25,347 $ 2,715,497 $ 81,947 $ 29,343 __________ (1) Excludes $35.4 billion and $37.1 billion as of June 30, 2017 and December 31, 2016 , respectively, of mortgage loans guaranteed or insured, in whole or in part, by the U.S. government or one of its agencies, that are not Alt-A loans. The segment class is primarily reverse mortgages for which we do not calculate an estimated mark-to-market LTV ratio. (2) The aggregate estimated mark-to-market LTV ratio is based on the unpaid principal balance of the loan as of the end of each reported period divided by the estimated current value of the property, which we calculate using an internal valuation model that estimates periodic changes in home value.
Multifamily [Member]
Mortgage Loans on Real Estate [Line Items]
Credit Quality Indicators [Table Text Block]	The following table displays the total recorded investment in our multifamily HFI loans by credit quality indicator, excluding loans for which we have elected the fair value option. As of June 30, December 31, 2017 2016 (Dollars in millions) Credit risk profile by internally assigned grade: Non-classified $ 243,555 $ 228,749 Classified: (1) Substandard 3,069 3,129 Doubtful 4 3 Total classified 3,073 3,132 Total $ 246,628 $ 231,881 _________ (1) A loan classified as “Substandard” has a well-defined weakness that jeopardizes the timely full repayment. “Doubtful” refers to a loan with a weakness that makes collection or liquidation in full highly questionable and improbable based on existing conditions and values.

Allowance for Loan Losses (Tabl

Allowance for Loan Losses (Tables)	6 Months Ended
	Jun. 30, 2017
Receivables [Abstract]
Allowance for Loan Losses Rollforward by Segment [Table Text Block]	The following table displays changes in single-family, multifamily and total allowance for loan losses. For the Three Months Ended June 30, For the Six Months Ended June 30, 2017 2016 2017 2016 (Dollars in millions) Single-family allowance for loan losses: Beginning balance $ 21,938 $ 25,597 $ 23,283 $ 27,709 Benefit for loan losses (1) (1,185 ) (1,332 ) (1,605 ) (2,348 ) Charge-offs (689 ) (818 ) (1,729 ) (2,097 ) Recoveries 146 115 231 234 Other (2) 8 22 38 86 Ending balance $ 20,218 $ 23,584 $ 20,218 $ 23,584 Multifamily allowance for loan losses: Beginning balance $ 191 $ 222 $ 182 $ 242 Benefit for loan losses (1) (11 ) (4 ) (2 ) (20 ) Charge-offs — (3 ) — (8 ) Recoveries 1 — 1 1 Ending balance $ 181 $ 215 $ 181 $ 215 Total allowance for loan losses: Beginning balance $ 22,129 $ 25,819 $ 23,465 $ 27,951 Benefit for loan losses (1) (1,196 ) (1,336 ) (1,607 ) (2,368 ) Charge-offs (689 ) (821 ) (1,729 ) (2,105 ) Recoveries 147 115 232 235 Other (2) 8 22 38 86 Ending balance $ 20,399 $ 23,799 $ 20,399 $ 23,799 __________ (1) Benefit for loan losses is included in “ Benefit for credit losses ” in our condensed consolidated statements of operations and comprehensive income. (2) Amounts represent changes in other loss reserves which are reflected in benefit for loan losses, charge-offs, and recoveries.
Allowance for Loan Losses and Total Recorded Investment in HFI Loans [Table Text Block]	The following table displays the carrying value of our mortgage loans. As of June 30, 2017 December 31, 2016 (Dollars in millions) Single-family $ 2,861,253 $ 2,833,750 Multifamily 244,701 229,896 Total unpaid principal balance of mortgage loans 3,105,954 3,063,646 Cost basis and fair value adjustments, net 39,860 39,572 Allowance for loan losses for loans held for investment (20,399 ) (23,465 ) Total mortgage loans $ 3,125,415 $ 3,079,753 The following table displays the allowance for loan losses and recorded investment in our HFI loans, excluding loans for which we have elected the fair value option, by impairment or allowance methodology and portfolio segment. As of June 30, 2017 December 31, 2016 Single-Family Multifamily Total Single-Family Multifamily Total (Dollars in millions) Allowance for loan losses by segment: Individually impaired loans (1) $ 19,197 $ 41 $ 19,238 $ 21,920 $ 33 $ 21,953 Collectively reserved loans 1,021 140 1,161 1,363 149 1,512 Total allowance for loan losses $ 20,218 $ 181 $ 20,399 $ 23,283 $ 182 $ 23,465 Recorded investment in loans by segment: Individually impaired loans (1) $ 144,833 $ 487 $ 145,320 $ 155,598 $ 589 $ 156,187 Collectively reserved loans 2,745,268 246,141 2,991,409 2,708,337 231,292 2,939,629 Total recorded investment in loans $ 2,890,101 $ 246,628 $ 3,136,729 $ 2,863,935 $ 231,881 $ 3,095,816 __________ (1) Includes acquired credit-impaired loans.

Investments in Securities (Tabl

Investments in Securities (Tables)	6 Months Ended
	Jun. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Investments In Trading Securities [Table Text Block]	The following table displays our investments in trading securities. As of June 30, 2017 December 31, 2016 (Dollars in millions) Mortgage-related securities: Fannie Mae $ 4,277 $ 4,769 Other agency 1,969 2,058 Alt-A and subprime private-label securities 593 636 Commercial mortgage-backed securities (“CMBS”) 16 761 Mortgage revenue bonds 1 21 Total mortgage-related securities 6,856 8,245 U.S. Treasury securities 32,418 32,317 Total trading securities $ 39,274 $ 40,562
Schedule of Realized Gain (Loss) [Table Text Block]	The following table displays the gross realized gains, losses and proceeds on sales of AFS securities. For the Three For the Six Months Ended Months Ended June 30, June 30, 2017 2016 2017 2016 (Dollars in millions) Gross realized gains $ 227 $ 234 $ 230 $ 445 Gross realized losses — 8 — 12 Total proceeds (excludes initial sale of securities from new portfolio securitizations) 799 3,645 894 7,267
Schedule of Available-for-sale Securities Reconciliation [Table Text Block]	The following tables display the amortized cost, gross unrealized gains and losses, and fair value by major security type for AFS securities. As of June 30, 2017 Total Amortized Cost (1) Gross Unrealized Gains Gross Unrealized Losses (2) Total Fair Value (Dollars in millions) Fannie Mae $ 2,173 $ 124 $ (25 ) $ 2,272 Other agency 399 33 — 432 Alt-A and subprime private-label securities 1,335 828 (1 ) 2,162 CMBS 259 — — 259 Mortgage revenue bonds 858 21 (6 ) 873 Other mortgage-related securities 395 15 — 410 Total $ 5,419 $ 1,021 $ (32 ) $ 6,408 As of December 31, 2016 Total Amortized Cost (1) Gross Unrealized Gains Gross Unrealized Losses (2) Total Fair Value (Dollars in millions) Fannie Mae $ 2,445 $ 137 $ (28 ) $ 2,554 Other agency 508 39 — 547 Alt-A and subprime private-label securities 1,817 895 (3 ) 2,709 CMBS 815 4 — 819 Mortgage revenue bonds 1,245 36 (9 ) 1,272 Other mortgage-related securities 431 31 — 462 Total $ 7,261 $ 1,142 $ (40 ) $ 8,363 __________ (1) Amortized cost consists of unpaid principal balance, unamortized premiums, discounts and other cost basis adjustments, as well as net other-than-temporary impairments (“OTTI”) recognized in “ Investment gains, net ” in our condensed consolidated statements of operations and comprehensive income. (2) Represents the gross unrealized losses on securities for which we have not recognized OTTI, as well as the noncredit component of OTTI and cumulative changes in fair value of securities for which we previously recognized the credit component of OTTI in “ Accumulated other comprehensive income ” in our condensed consolidated balance sheets.
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Table Text Block]	The following tables display additional information regarding gross unrealized losses and fair value by major security type for AFS securities in an unrealized loss position. As of June 30, 2017 Less Than 12 Consecutive Months 12 Consecutive Months or Longer Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value (Dollars in millions) Fannie Mae $ (2 ) $ 194 $ (23 ) $ 443 Alt-A and subprime private-label securities — — (1 ) 64 Mortgage revenue bonds — — (6 ) 17 Total $ (2 ) $ 194 $ (30 ) $ 524 As of December 31, 2016 Less Than 12 Consecutive Months 12 Consecutive Months or Longer Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value (Dollars in millions) Fannie Mae $ (2 ) $ 139 $ (26 ) $ 477 Alt-A and subprime private-label securities — — (3 ) 73 Mortgage revenue bonds (7 ) 78 (2 ) 6 Total $ (9 ) $ 217 $ (31 ) $ 556
Investments Classified by Contractual Maturity Date [Table Text Block]	The following table displays the amortized cost and fair value of our AFS securities by major security type and remaining contractual maturity, assuming no principal prepayments. The contractual maturity of mortgage-backed securities is not a reliable indicator of their expected life because borrowers generally have the right to prepay their obligations at any time. As of June 30, 2017 Total Amortized Cost Total Fair Value One Year or Less After One Year Through Five Years After Five Years Through Ten Years After Ten Years Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value (Dollars in millions) Fannie Mae $ 2,173 $ 2,272 $ 2 $ 2 $ 13 $ 14 $ 64 $ 68 $ 2,094 $ 2,188 Other agency 399 432 1 1 26 26 62 66 310 339 Alt-A and subprime private-label securities 1,335 2,162 — — — — — — 1,335 2,162 CMBS 259 259 259 259 — — — — — — Mortgage revenue bonds 858 873 10 10 75 75 112 114 661 674 Other mortgage-related securities 395 410 — — — — 3 3 392 407 Total $ 5,419 $ 6,408 $ 272 $ 272 $ 114 $ 115 $ 241 $ 251 $ 4,792 $ 5,770

Financial Guarantees (Tables)

Financial Guarantees (Tables)	6 Months Ended
	Jun. 30, 2017
Guarantees [Abstract]
Financial Guarantees and Maximum Recovery [Table Text Block]	The following table displays our maximum exposure, guaranty obligation recognized in our condensed consolidated balance sheets, and the maximum potential recovery from third parties through available credit enhancements and recourse related to our financial guarantees. As of June 30, 2017 December 31, 2016 Maximum Exposure (1) Guaranty Obligation Maximum Recovery (2) Maximum Exposure (1) Guaranty Obligation Maximum Recovery (2) (Dollars in millions) Unconsolidated Fannie Mae MBS $ 11,619 $ 134 $ 7,636 $ 12,607 $ 143 $ 8,048 Other guaranty arrangements (3) 14,632 130 2,499 15,335 137 2,663 Total $ 26,251 $ 264 $ 10,135 $ 27,942 $ 280 $ 10,711 __________ (1) Primarily consists of the unpaid principal balance of the underlying mortgage loans. (2) Recoverability of such credit enhancements and recourse is subject to, among other factors, our mortgage insurers’ and financial guarantors’ ability to meet their obligations to us. For information on our mortgage insurers and financial guarantors, see “Note 15, Concentrations of Credit Risk” in our 2016 Form 10-K . (3) Primarily consists of credit enhancements and long-term standby commitments.

Short-Term Borrowings and Lon38

Short-Term Borrowings and Long-Term Debt (Tables)	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Short-Term Borrowings [Table Text Block]	The following table displays our outstanding short-term borrowings (borrowings with an original contractual maturity of one year or less) and weighted-average interest rates of these borrowings. As of June 30, 2017 December 31, 2016 Outstanding Weighted- Average Interest Rate (1) Outstanding Weighted- Average Interest Rate (1) (Dollars in millions) Federal funds purchased and securities sold under agreements to repurchase (2) $ 7 0.25 % $ — — % Short-term debt of Fannie Mae $ 30,501 0.84 % $ 34,995 0.49 % Debt of consolidated trusts 511 0.91 584 0.48 Total short-term debt $ 31,012 0.84 % $ 35,579 0.49 % __________ (1) Includes the effects of discounts, premiums and other cost basis adjustments. (2) Represents agreements to repurchase securities for a specified price, with repayment generally occurring on the following day.
Long-Term Debt [Table Text Block]	The following table displays our outstanding long-term debt. As of June 30, 2017 December 31, 2016 Maturities Outstanding Weighted- Average Interest Rate (1) Maturities Outstanding Weighted- Average Interest Rate (1) (Dollars in millions) Senior fixed: Benchmark notes and bonds 2017 - 2030 $ 137,509 1.96 % 2017 - 2030 $ 153,983 2.16 % Medium-term notes (2) 2017 - 2026 82,215 1.42 2017 - 2026 82,230 1.40 Other (3) 2017 - 2038 7,926 4.82 2017 - 2038 12,800 6.74 Total senior fixed 227,650 1.87 249,013 2.14 Senior floating: Medium-term notes (2) 2017 - 2020 19,051 1.11 2017 - 2019 21,476 0.71 Connecticut Avenue Securities (4) 2023 - 2029 20,589 5.03 2023 - 2029 16,511 4.77 Other (5) 2020 - 2037 365 7.20 2020 - 2037 346 6.75 Total senior floating 40,005 3.14 38,333 2.48 Subordinated debentures 2019 4,870 9.93 2019 4,645 9.93 Secured borrowings (6) 2021 - 2022 94 1.60 2021 - 2022 111 1.44 Total long-term debt of Fannie Mae (7) 272,619 2.20 292,102 2.31 Debt of consolidated trusts 2017 - 2056 2,984,036 2.78 2017 - 2056 2,934,635 2.57 Total long-term debt $ 3,256,655 2.73 % $ 3,226,737 2.54 % __________ (1) Includes the effects of discounts, premiums and other cost basis adjustments. (2) Includes long-term debt with an original contractual maturity of greater than 1 year and up to 10 years, excluding zero-coupon debt. (3) Includes other long-term debt with an original contractual maturity of greater than 10 years and foreign exchange bonds. (4) Credit risk-sharing securities that transfer a portion of the credit risk on specified pools of single-family mortgage loans to the investors in these securities, a portion of which is reported at fair value. (5) Consists of structured debt instruments that are reported at fair value. (6) Represents our remaining liability resulting from the transfer of financial assets from our condensed consolidated balance sheets that did not qualify as a sale under the accounting guidance for the transfer of financial instruments. (7) Includes unamortized discounts and premiums, other cost basis adjustments and fair value adjustments of $1.0 billion and $1.8 billion as of June 30, 2017 and December 31, 2016 , respectively.

Derivative Instruments (Tables)

Derivative Instruments (Tables)	6 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Notional and Fair Value Position [Table Text Block]	The following table displays the notional amount and estimated fair value of our asset and liability derivative instruments. As of June 30, 2017 As of December 31, 2016 Asset Derivatives Liability Derivatives Asset Derivatives Liability Derivatives Notional Amount Estimated Fair Value Notional Amount Estimated Fair Value Notional Amount Estimated Fair Value Notional Amount Estimated Fair Value (Dollars in millions) Risk management derivatives: Swaps: Pay-fixed $ 32,746 $ 441 $ 79,878 $ (2,983 ) $ 29,540 $ 660 $ 94,584 $ (4,396 ) Receive-fixed 33,890 2,604 134,172 (1,051 ) 30,207 2,696 135,470 (1,552 ) Basis 12,873 127 1,350 (1 ) 1,624 115 15,600 (11 ) Foreign currency 226 49 228 (72 ) 214 40 216 (85 ) Swaptions: Pay-fixed 10,250 179 2,350 (3 ) 9,600 241 4,850 (82 ) Receive-fixed — — 8,350 (271 ) — — 10,100 (257 ) Other (1) 24,203 23 — (1 ) 15,087 33 655 (2 ) Total gross risk management derivatives 114,188 3,423 226,328 (4,382 ) 86,272 3,785 261,475 (6,385 ) Accrued interest receivable (payable) — 707 — (754 ) — 785 — (937 ) Netting adjustment (2) — (4,024 ) — 5,034 — (4,514 ) — 6,844 Total net risk management derivatives $ 114,188 $ 106 $ 226,328 $ (102 ) $ 86,272 $ 56 $ 261,475 $ (478 ) Mortgage commitment derivatives: Mortgage commitments to purchase whole loans $ 1,898 $ 5 $ 6,698 $ (27 ) $ 4,753 $ 28 $ 3,039 $ (49 ) Forward contracts to purchase mortgage-related securities 11,791 37 69,343 (243 ) 31,635 198 27,297 (388 ) Forward contracts to sell mortgage-related securities 100,370 271 16,793 (48 ) 34,103 405 47,645 (300 ) Total mortgage commitment derivatives $ 114,059 $ 313 $ 92,834 $ (318 ) $ 70,491 $ 631 $ 77,981 $ (737 ) Derivatives at fair value $ 228,247 $ 419 $ 319,162 $ (420 ) $ 156,763 $ 687 $ 339,456 $ (1,215 ) __________ (1) Includes credit risk transfer transactions, futures, swap credit enhancements and mortgage insurance contracts that we account for as derivatives. (2) The netting adjustment represents the effect of the legal right to offset under legally enforceable master netting arrangements to settle with the same counterparty on a net basis, including cash collateral posted and received. Cash collateral posted was $1.6 billion and $2.9 billion as of June 30, 2017 and December 31, 2016 , respectively. Cash collateral received was $599 million and $535 million as of June 30, 2017 and December 31, 2016 , respectively.
Fair Value Gain (Loss), Net [Table Text Block]	The following table displays, by type of derivative instrument, the fair value gains and losses, net on our derivatives. For the Three Months For the Six Months Ended June 30, Ended June 30, 2017 2016 2017 2016 (Dollars in millions) Risk management derivatives: Swaps: Pay-fixed $ (691 ) $ (2,257 ) $ — $ (7,430 ) Receive-fixed 639 1,371 322 4,358 Basis 16 14 23 49 Foreign currency 11 (34 ) 23 (31 ) Swaptions: Pay-fixed (48 ) 4 (48 ) 29 Receive-fixed (8 ) (19 ) (26 ) (136 ) Other 3 22 (5 ) 160 Net accrual of periodic settlements (224 ) (291 ) (479 ) (560 ) Total risk management derivatives fair value losses, net $ (302 ) $ (1,190 ) $ (190 ) $ (3,561 ) Mortgage commitment derivatives fair value losses, net (192 ) (367 ) (272 ) (729 ) Total derivatives fair value losses, net $ (494 ) $ (1,557 ) $ (462 ) $ (4,290 )

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	The following table displays the computation of basic and diluted earnings per share of common stock. For the Three Months Ended June 30, For the Six Months Ended June 30, 2017 2016 2017 2016 (Dollars and shares in millions, except per share amounts) Net income $ 3,200 $ 2,946 $ 5,973 $ 4,082 Dividends distributed or available for distribution to senior preferred stockholder (1) (3,117 ) (2,869 ) (5,896 ) (3,788 ) Net income attributable to common stockholders $ 83 $ 77 $ 77 $ 294 Weighted-average common shares outstanding—Basic (2) 5,762 5,762 5,762 5,762 Convertible preferred stock 131 131 131 131 Weighted-average common shares outstanding—Diluted (2) 5,893 5,893 5,893 5,893 Earnings per share: Basic $ 0.01 $ 0.01 $ 0.01 $ 0.05 Diluted 0.01 0.01 0.01 0.05 __________ (1) Dividends distributed or available for distribution were calculated based on our net worth as of the end of the fiscal quarters, less the applicable capital reserve amount. See “ Note 1, Summary of Significant Accounting Policies ” in this report and in our 2016 Form 10-K for additional information on our senior preferred stock agreement and our payment of dividends to Treasury. (2) Includes 4.6 billion of weighted average shares of common stock that would be issued upon the full exercise of the warrant issued to Treasury from the date the warrant was issued through June 30, 2017 and 2016 .

Segment Reporting (Tables)

Segment Reporting (Tables)	6 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
Segment results [Table Text Block]	For the Three Months Ended June 30, 2017 2016 Single-Family Multifamily Total Single-Family Multifamily Total (Dollars in millions) Net interest income (1) $ 4,366 $ 636 $ 5,002 $ 4,730 $ 556 $ 5,286 Fee and other income (2) 111 242 353 78 96 174 Net revenues 4,477 878 5,355 4,808 652 5,460 Investment gains, net (3) 321 64 385 280 118 398 Fair value gains (losses), net (4) (685 ) (6 ) (691 ) (1,679 ) 12 (1,667 ) Administrative expenses (600 ) (86 ) (686 ) (597 ) (81 ) (678 ) Credit-related income (5) Benefit for credit losses 1,255 12 1,267 1,596 5 1,601 Foreclosed property expense (32 ) (2 ) (34 ) (61 ) (2 ) (63 ) Total credit-related income 1,223 10 1,233 1,535 3 1,538 TCCA fees (6) (518 ) — (518 ) (453 ) — (453 ) Other expenses, net (155 ) (136 ) (291 ) (252 ) (2 ) (254 ) Income before federal income taxes 4,063 724 4,787 3,642 702 4,344 Provision for federal income taxes (1,401 ) (186 ) (1,587 ) (1,254 ) (144 ) (1,398 ) Net income $ 2,662 $ 538 $ 3,200 $ 2,388 $ 558 $ 2,946 For the Six Months Ended June 30, 2017 2016 Single-Family Multifamily Total Single-Family Multifamily Total (Dollars in millions) Net interest income (1) $ 9,122 $ 1,226 $ 10,348 $ 8,975 $ 1,080 $ 10,055 Fee and other income (2) 187 415 602 145 232 377 Net revenues 9,309 1,641 10,950 9,120 1,312 10,432 Investment gains, net (3) 271 105 376 336 131 467 Fair value gains (losses), net (4) (697 ) (34 ) (731 ) (4,529 ) 49 (4,480 ) Administrative expenses (1,201 ) (169 ) (1,370 ) (1,206 ) (160 ) (1,366 ) Credit-related income (5) Benefit for credit losses 1,655 8 1,663 2,759 26 2,785 Foreclosed property expense (248 ) (3 ) (251 ) (396 ) (1 ) (397 ) Total credit-related income 1,407 5 1,412 2,363 25 2,388 TCCA fees (6) (1,021 ) — (1,021 ) (893 ) — (893 ) Other expenses, net (411 ) (262 ) (673 ) (498 ) (20 ) (518 ) Income before federal income taxes 7,657 1,286 8,943 4,693 1,337 6,030 Provision for federal income taxes (2,653 ) (317 ) (2,970 ) (1,643 ) (305 ) (1,948 ) Net income $ 5,004 $ 969 $ 5,973 $ 3,050 $ 1,032 $ 4,082 __________ (1) Net interest income primarily consists of guaranty fees received as compensation for assuming and managing the credit risk on loans underlying Fannie Mae MBS held by third parties for the respective business segment, and the difference between the interest income earned on the respective business segment’s mortgage assets in our retained mortgage portfolio and the interest expense associated with the debt funding those assets. Revenues from single-family guaranty fees include revenues generated by the 10 basis point increase in guaranty fees we implemented in 2012 pursuant to TCCA. (2) Single-Family fee and other income primarily consists of compensation for engaging in structured transactions and providing other lender services, and income resulting from settlement agreements resolving certain claims relating to private-label securities sold to us or that we have guaranteed. Multifamily fee and other income consists of fees associated with multifamily business activities, including yield maintenance income. (3) Investment gains and losses primarily consists of gains and losses on the sale of mortgage assets for the respective business segment. (4) Single-Family fair value gains and losses primarily consist of fair value gains and losses on risk management and mortgage commitment derivatives, trading securities and other financial instruments associated with our single-family mortgage credit book of business. Multifamily fair value gains and losses primarily consist of fair value gains and losses on MBS commitment derivatives, trading securities and other financial instruments associated with our multifamily mortgage credit book of business. (5) Credit-related income or expense is based on the guaranty book of business of the respective business segment and consists of the applicable segment’s benefit or provision for credit losses and foreclosed property expense on loans underlying the segment’s guaranty book of business. (6) Consists of the portion of our single-family guaranty fees that is remitted to Treasury pursuant to the TCCA.

Equity (Tables)

Equity (Tables)	6 Months Ended
	Jun. 30, 2017
Equity [Abstract]
Schedule of Other Comprehensive Income (Loss) [Table Text Block]	The following table displays the activity in other comprehensive loss, net of tax, by major categories. For the Three Months Ended June 30, For the Six Months Ended June 30, 2017 2016 2017 2016 (Dollars in millions) Net income $ 3,200 $ 2,946 $ 5,973 $ 4,082 Other comprehensive loss, net of tax effect: Changes in net unrealized gains (losses) on AFS securities (net of tax of $6 and $27, respectively, for the three months ended and net of tax of $11 and $21, respectively, for the six months ended) 11 50 20 (39 ) Reclassification adjustment for OTTI recognized in net income (net of tax of $0 and $1, respectively, for the three months ended and net of tax of $0 and $11, respectively, for the six months ended) — 1 1 20 Reclassification adjustment for gains on AFS securities included in net income (net of tax of $50 and $68, respectively, for the three months ended and net of tax of $51 and $137, respectively, for the six months ended) (92 ) (126 ) (94 ) (254 ) Other (2 ) (2 ) (4 ) (4 ) Total other comprehensive loss (83 ) (77 ) (77 ) (277 ) Total comprehensive income $ 3,117 $ 2,869 $ 5,896 $ 3,805
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following table displays our accumulated other comprehensive income by major categories. As of June 30, December 31, 2017 2016 (Dollars in millions) Net unrealized gains on AFS securities for which we have not recorded OTTI, net of tax $ 108 $ 135 Net unrealized gains on AFS securities for which we have recorded OTTI, net of tax 535 581 Other, net of tax 39 43 Accumulated other comprehensive income $ 682 $ 759 The table below displays changes in accumulated other comprehensive income, net of tax. For the Three Months Ended June 30, For the Six Months Ended June 30, 2017 2016 2017 2016 AFS (1) Other Total AFS (1) Other Total AFS (1) Other Total AFS (1) Other Total (Dollars in millions) Beginning balance $ 724 $ 41 $ 765 $ 1,160 $ 47 $ 1,207 $ 716 $ 43 $ 759 $ 1,358 $ 49 $ 1,407 Other comprehensive income (loss) before reclassifications 11 — 11 50 — 50 20 — 20 (39 ) — (39 ) Amounts reclassified from other comprehensive income (loss) (92 ) (2 ) (94 ) (125 ) (2 ) (127 ) (93 ) (4 ) (97 ) (234 ) (4 ) (238 ) Net other comprehensive income (loss) (81 ) (2 ) (83 ) (75 ) (2 ) (77 ) (73 ) (4 ) (77 ) (273 ) (4 ) (277 ) Ending balance $ 643 $ 39 $ 682 $ 1,085 $ 45 $ 1,130 $ 643 $ 39 $ 682 $ 1,085 $ 45 $ 1,130 __________ (1) The amounts reclassified from accumulated other comprehensive income represent the gain or loss recognized in earnings due to a sale of an AFS security or the recognition of a net impairment recognized in earnings, which are recorded in “ Investment gains, net ” in our condensed consolidated statements of operations and comprehensive income.

Concentrations of Credit Risk (

Concentrations of Credit Risk (Tables)	6 Months Ended
	Jun. 30, 2017
Single-family [Member]
Concentration Risk [Line Items]
Schedule of Delinquency Status Guaranty Book of Business [Table Text Block]	The following tables display the delinquency status and serious delinquency rates for specified loan categories of our single-family conventional and total multifamily guaranty book of business. As of June 30, 2017 (1) December 31, 2016 (1) 30 Days Delinquent 60 Days Delinquent Seriously Delinquent (2) 30 Days Delinquent 60 Days Delinquent Seriously Delinquent (2) Percentage of single-family conventional guaranty book of business (3) 1.14 % 0.30 % 0.98 % 1.30 % 0.36 % 1.18 % Percentage of single-family conventional loans (4) 1.32 0.34 1.01 1.51 0.41 1.20
Schedule of Risk Characteristics Guaranty Book of Business [Table Text Block]	As of June 30, 2017 (1) December 31, 2016 (1) Percentage of Single-Family Conventional Guaranty Book of Business (3) Seriously Delinquent Rate (2) Percentage of Single-Family Conventional Guaranty Book of Business (3) Seriously Delinquent Rate (2) Estimated mark-to-market loan-to-value ratio: Greater than 100% 1 % 10.05 % 2 % 10.44 % Geographical distribution: California 19 0.43 19 0.50 Florida 6 1.51 6 1.89 New Jersey 4 2.49 4 3.07 New York 5 2.21 5 2.65 All other states 66 0.94 66 1.11 Product distribution: Alt-A 3 4.52 3 5.00 Vintages: 2004 and prior 4 2.62 5 2.82 2005-2008 7 5.73 8 6.39 2009-2017 89 0.32 87 0.36 __________ (1) Consists of the portion of our single-family conventional guaranty book of business for which we have detailed loan level information, which constituted approximately 99% of our total single-family conventional guaranty book of business as of June 30, 2017 and December 31, 2016 . (2) Consists of single-family conventional loans that were 90 days or more past due or in the foreclosure process as of June 30, 2017 and December 31, 2016 . (3) Calculated based on the aggregate unpaid principal balance of single-family conventional loans for each category divided by the aggregate unpaid principal balance of loans in our single-family conventional guaranty book of business. (4) Calculated based on the number of single-family conventional loans that were delinquent divided by the total number of loans in our single-family conventional guaranty book of business.
Multifamily [Member]
Concentration Risk [Line Items]
Schedule of Delinquency Status Guaranty Book of Business [Table Text Block]	As of June 30, 2017 (1)(2) December 31, 2016 (1)(2) 30 Days Delinquent Seriously Delinquent (3) 30 Days Delinquent Seriously Delinquent (3) Percentage of multifamily guaranty book of business 0.01 % 0.04 % 0.02 % 0.05 %
Schedule of Risk Characteristics Guaranty Book of Business [Table Text Block]	As of June 30, 2017 (1) December 31, 2016 (1) Percentage of Multifamily Guaranty Book of Business (2) Percentage Seriously Delinquent (3)(4) Percentage of Multifamily Guaranty Book of Business (2) Percentage Seriously Delinquent (3)(4) Original LTV ratio: Greater than 80% 2 % 0.17 % 2 % 0.22 % Less than or equal to 80% 98 0.04 98 0.05 Current DSCR less than 1.0 (5) 1 2.12 2 1.96 __________ (1) Consists of the portion of our multifamily guaranty book of business for which we have detailed loan level information, which constituted approximately 99% of our total multifamily guaranty book of business as of June 30, 2017 and December 31, 2016 , excluding loans that have been defeased. (2) Calculated based on the aggregate unpaid principal balance of multifamily loans for each category divided by the aggregate unpaid principal balance of loans in our multifamily guaranty book of business. (3) Consists of multifamily loans that were 60 days or more past due as of the dates indicated. (4) Calculated based on the unpaid principal balance of multifamily loans that were seriously delinquent divided by the aggregate unpaid principal balance of multifamily loans for each category included in our guaranty book of business. (5) Our estimates of current DSCRs are based on the latest available income information for these properties. Although we use the most recently available results of our multifamily borrowers, there is a lag in reporting, which typically can range from 3 to 6 months but in some cases may be longer.

Netting Arrangements (Tables)

Netting Arrangements (Tables)	6 Months Ended
	Jun. 30, 2017
Offsetting [Abstract]
Offsetting [Table Text Block]	The tables below display information related to derivatives, securities purchased under agreements to resell or similar arrangements, and securities sold under agreements to repurchase or similar arrangements, which are subject to an enforceable master netting arrangement or similar agreement that are either offset or not offset in our condensed consolidated balance sheets. As of June 30, 2017 Net Amount Presented in our Condensed Consolidated Balance Sheets Amounts Not Offset in our Condensed Consolidated Balance Sheets Gross Amount Gross Amount Offset (1) Financial Instruments (2) Collateral (3) Net Amount (Dollars in millions) Assets: OTC risk management derivatives $ 2,800 $ (2,753 ) $ 47 $ — $ — $ 47 Cleared risk management derivatives 1,307 (1,271 ) 36 — — 36 Mortgage commitment derivatives 313 — 313 (234 ) — 79 Total derivative assets 4,420 (4,024 ) 396 (4) (234 ) — 162 Securities purchased under agreements to resell or similar arrangements (5) 41,120 — 41,120 — (41,120 ) — Total assets $ 45,540 $ (4,024 ) $ 41,516 $ (234 ) $ (41,120 ) $ 162 Liabilities: OTC risk management derivatives $ (3,564 ) $ 3,465 $ (99 ) $ — $ — $ (99 ) Cleared risk management derivatives (1,571 ) 1,569 (2 ) — 2 — Mortgage commitment derivatives (318 ) — (318 ) 234 — (84 ) Total derivative liabilities (5,453 ) 5,034 (419 ) (4) 234 2 (183 ) Securities sold under agreements to repurchase or similar arrangements (7 ) — (7 ) — 7 — Total liabilities $ (5,460 ) $ 5,034 $ (426 ) $ 234 $ 9 $ (183 ) As of December 31, 2016 Net Amount Presented in our Condensed Consolidated Balance Sheets Amounts Not Offset in our Condensed Consolidated Balance Sheets Gross Amount Gross Amount Offset (1) Financial Instruments (2) Collateral (3) Net Amount (Dollars in millions) Assets: OTC risk management derivatives $ 3,688 $ (3,667 ) $ 21 $ — $ — $ 21 Cleared risk management derivatives 849 (847 ) 2 — — 2 Mortgage commitment derivatives 631 — 631 (357 ) (22 ) 252 Total derivative assets 5,168 (4,514 ) 654 (4) (357 ) (22 ) 275 Securities purchased under agreements to resell or similar arrangements (5) 51,115 — 51,115 — (51,115 ) — Total assets $ 56,283 $ (4,514 ) $ 51,769 $ (357 ) $ (51,137 ) $ 275 Liabilities: OTC risk management derivatives $ (4,905 ) $ 4,520 $ (385 ) $ — $ — $ (385 ) Cleared risk management derivatives (2,415 ) 2,324 (91 ) — 91 — Mortgage commitment derivatives (737 ) — (737 ) 357 16 (364 ) Total derivative liabilities (8,057 ) 6,844 (1,213 ) (4) 357 107 (749 ) Total liabilities $ (8,057 ) $ 6,844 $ (1,213 ) $ 357 $ 107 $ (749 ) __________ (1) Represents the effect of the right to offset under legally enforceable master netting arrangements to settle with the same counterparty on a net basis, including cash collateral posted and received and accrued interest. (2) Mortgage commitment derivative amounts reflect where we have recognized both an asset and a liability with the same counterparty under an enforceable master netting arrangement but we have not elected to offset the related amounts in our condensed consolidated balance sheets. (3) Represents non-cash collateral received that has not been recognized and not offset in our condensed consolidated balance sheets as well as non-cash collateral posted which has been recognized but not offset in our condensed consolidated balance sheets. Does not include collateral held or posted in excess of our exposure. The fair value of non-cash collateral we pledged was $1.0 billion and $1.3 billion as of June 30, 2017 and December 31, 2016 , respectively, which the counterparty was permitted to sell or repledge. The fair value of non-cash collateral received was $41.2 billion and $51.2 billion , of which $38.9 billion and $45.5 billion could be sold or repledged as of June 30, 2017 and December 31, 2016 , respectively. None of the underlying collateral was sold or repledged as of June 30, 2017 and December 31, 2016 . (4) Excludes derivative assets of $23 million and $33 million as of June 30, 2017 and December 31, 2016 , and derivative liabilities of $1 million and $2 million recognized in our condensed consolidated balance sheets as of June 30, 2017 and December 31, 2016 , respectively, that are not subject to enforceable master netting arrangements. (5) Includes $11.9 billion and $20.7 billion of securities purchased under agreements to resell classified as “Cash and cash equivalents” in our condensed consolidated balance sheets as of June 30, 2017 and December 31, 2016 , respectively.

Fair Value (Tables)

Fair Value (Tables)	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Recurring Changes in Fair Value [Table Text Block]	The following tables display our assets and liabilities measured in our condensed consolidated balance sheets at fair value on a recurring basis subsequent to initial recognition, including instruments for which we have elected the fair value option. Fair Value Measurements as of June 30, 2017 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Netting Adjustment (1) Estimated Fair Value (Dollars in millions) Recurring fair value measurements: Assets: Trading securities: Mortgage-related securities: Fannie Mae $ — $ 2,406 $ 1,871 $ — $ 4,277 Other agency — 1,969 — — 1,969 Alt-A and subprime private-label securities — 329 264 — 593 CMBS — 16 — — 16 Mortgage revenue bonds — — 1 — 1 Non-mortgage-related securities: U.S. Treasury securities 32,418 — — — 32,418 Total trading securities 32,418 4,720 2,136 — 39,274 Available-for-sale securities: Mortgage-related securities: Fannie Mae — 2,066 206 — 2,272 Other agency — 432 — — 432 Alt-A and subprime private-label securities — 1,984 178 — 2,162 CMBS — 259 — — 259 Mortgage revenue bonds — — 873 — 873 Other — 30 380 — 410 Total available-for-sale securities — 4,771 1,637 — 6,408 Mortgage loans — 10,287 1,119 — 11,406 Other assets: Risk management derivatives: Swaps — 3,784 144 — 3,928 Swaptions — 179 — — 179 Other — — 23 — 23 Netting adjustment — — — (4,024 ) (4,024 ) Mortgage commitment derivatives — 313 — — 313 Total other assets — 4,276 167 (4,024 ) 419 Total assets at fair value $ 32,418 $ 24,054 $ 5,059 $ (4,024 ) $ 57,507 Fair Value Measurements as of June 30, 2017 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Netting Adjustment (1) Estimated Fair Value (Dollars in millions) Liabilities: Long-term debt: Of Fannie Mae: Senior floating $ — $ 8,643 $ 365 $ — $ 9,008 Total of Fannie Mae — 8,643 365 — 9,008 Of consolidated trusts — 34,106 760 — 34,866 Total long-term debt — 42,749 1,125 — 43,874 Other liabilities: Risk management derivatives: Swaps — 4,837 24 — 4,861 Swaptions — 274 — — 274 Other — — 1 — 1 Netting adjustment — — — (5,034 ) (5,034 ) Mortgage commitment derivatives — 300 18 — 318 Total other liabilities — 5,411 43 (5,034 ) 420 Total liabilities at fair value $ — $ 48,160 $ 1,168 $ (5,034 ) $ 44,294 Fair Value Measurements as of December 31, 2016 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Netting Adjustment (1) Estimated Fair Value (Dollars in millions) Assets: Trading securities: Mortgage-related securities: Fannie Mae $ — $ 3,934 $ 835 $ — $ 4,769 Other agency — 2,058 — — 2,058 Alt-A and subprime private-label securities — 365 271 — 636 CMBS — 761 — — 761 Mortgage revenue bonds — — 21 — 21 Non-mortgage-related securities: U.S. Treasury securities 32,317 — — — 32,317 Total trading securities 32,317 7,118 1,127 — 40,562 Available-for-sale securities: Mortgage-related securities: Fannie Mae — 2,324 230 — 2,554 Other agency — 542 5 — 547 Alt-A and subprime private-label securities — 2,492 217 — 2,709 CMBS — 819 — — 819 Mortgage revenue bonds — — 1,272 — 1,272 Other — 33 429 — 462 Total available-for-sale securities — 6,210 2,153 — 8,363 Mortgage loans — 10,860 1,197 — 12,057 Other assets: Risk management derivatives: Swaps — 4,159 137 — 4,296 Swaptions — 241 — — 241 Other — — 33 — 33 Netting adjustment — — — (4,514 ) (4,514 ) Mortgage commitment derivatives — 619 12 — 631 Total other assets — 5,019 182 (4,514 ) 687 Total assets at fair value $ 32,317 $ 29,207 $ 4,659 $ (4,514 ) $ 61,669 Fair Value Measurements as of December 31, 2016 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Netting Adjustment (1) Estimated Fair Value (Dollars in millions) Liabilities: Long-term debt: Of Fannie Mae: Senior floating $ — $ 9,235 $ 347 $ — $ 9,582 Total of Fannie Mae — 9,235 347 — 9,582 Of consolidated trusts — 36,283 241 — 36,524 Total long-term debt — 45,518 588 — 46,106 Other liabilities: Risk management derivatives: Swaps — 6,933 48 — 6,981 Swaptions — 339 — — 339 Other — — 2 — 2 Netting adjustment — — — (6,844 ) (6,844 ) Mortgage commitment derivatives — 649 88 — 737 Total other liabilities — 7,921 138 (6,844 ) 1,215 Total liabilities at fair value $ — $ 53,439 $ 726 $ (6,844 ) $ 47,321 __________ (1) Derivative contracts are reported on a gross basis by level. The netting adjustment represents the effect of the legal right to offset under legally enforceable master netting arrangements to settle with the same counterparty on a net basis, including cash collateral posted and received.
Fair Value Measurements Using Significant Unobservable Inputs (Level 3) [Table Text Block]	The following tables display a reconciliation of all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3). The tables also display gains and losses due to changes in fair value, including realized and unrealized gains and losses, recognized in our condensed consolidated statements of operations and comprehensive income for Level 3 assets and liabilities. When assets and liabilities are transferred between levels, we recognize the transfer as of the end of the period. Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Three Months Ended June 30, 2017 Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of June 30, 2017 (5)(6) Total Gains (Losses) (Realized/Unrealized) Balance, March 31, 2017 Included in Net Income Included in Total Other Comprehensive Income (Loss) (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 Transfers into Level 3 (4) Balance, June 30, 2017 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 856 $ 1 $ — $ 63 $ — $ — $ (2 ) $ (21 ) $ 974 $ 1,871 $ — Alt-A and subprime private-label securities 272 3 — — — — (11 ) — — 264 2 Mortgage revenue bonds 20 3 — — (21 ) — (1 ) — — 1 — Total trading securities $ 1,148 $ 7 (6)(7) $ — $ 63 $ (21 ) $ — $ (14 ) $ (21 ) $ 974 $ 2,136 $ 2 Available-for-sale securities: Mortgage-related: Fannie Mae $ 232 $ — $ (3 ) $ — $ — $ — $ (2 ) $ (21 ) $ — $ 206 $ — Alt-A and subprime private-label securities 205 — (21 ) — — — (6 ) — — 178 — Mortgage revenue bonds 1,185 34 (11 ) — (312 ) — (23 ) — — 873 — Other 417 — (19 ) — — — (18 ) — — 380 — Total available-for-sale securities $ 2,039 $ 34 (7)(8) $ (54 ) $ — $ (312 ) $ — $ (49 ) $ (21 ) $ — $ 1,637 $ — Mortgage loans $ 1,149 $ 24 (6)(7) $ — $ — $ — $ — $ (55 ) $ (21 ) $ 22 $ 1,119 $ 19 Net derivatives 113 27 (6) — — — — (16 ) — — 124 9 Long-term debt: Of Fannie Mae: Senior floating $ (350 ) $ (15 ) $ — $ — $ — $ — $ — $ — $ — $ (365 ) $ (14 ) Of consolidated trusts (214 ) (5 ) — — — — 12 22 (575 ) (760 ) (5 ) Total long-term debt $ (564 ) $ (20 ) (6) $ — $ — $ — $ — $ 12 $ 22 $ (575 ) $ (1,125 ) $ (19 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Six Months Ended June 30, 2017 Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of June 30, 2017 (5)(6) Total Gains (Losses) (Realized/Unrealized) Balance, December 31, 2016 Included in Net Income Included in Total Other Comprehensive Income (Loss) (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 Transfers into Level 3 (4) Balance, June 30, 2017 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 835 $ 4 $ — $ 63 $ — $ — $ (5 ) $ (22 ) $ 996 $ 1,871 $ 2 Alt-A and subprime private-label securities 271 11 — — — — (18 ) — — 264 11 Mortgage revenue bonds 21 3 — — (21 ) — (2 ) — — 1 — Total trading securities $ 1,127 $ 18 (6)(7) $ — $ 63 $ (21 ) $ — $ (25 ) $ (22 ) $ 996 $ 2,136 $ 13 Available-for-sale securities: Mortgage-related: Fannie Mae $ 230 $ 1 $ (2 ) $ — $ — $ — $ (6 ) $ (47 ) $ 30 $ 206 $ — Other agency 5 — — — (1 ) — — (4 ) — — — Alt-A and subprime private-label securities 217 — (15 ) — — — (24 ) — — 178 — Mortgage revenue bonds 1,272 35 (12 ) — (324 ) — (98 ) — — 873 — Other 429 — (14 ) — — — (35 ) — — 380 — Total available-for-sale securities $ 2,153 $ 36 (7)(8) $ (43 ) $ — $ (325 ) $ — $ (163 ) $ (51 ) $ 30 $ 1,637 $ — Mortgage loans $ 1,197 $ 32 (6)(7) $ — $ — $ — $ — $ (117 ) $ (67 ) $ 74 $ 1,119 $ 16 Net derivatives 44 100 (6) — — — — (24 ) 5 (1 ) 124 — Long-term debt: Of Fannie Mae: Senior floating $ (347 ) $ (18 ) $ — $ — $ — $ — $ — $ — $ — $ (365 ) $ (18 ) Of consolidated trusts (241 ) (4 ) — — — (2 ) 19 88 (620 ) (760 ) (4 ) Total long-term debt $ (588 ) $ (22 ) (6) $ — $ — $ — $ (2 ) $ 19 $ 88 $ (620 ) $ (1,125 ) $ (22 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Three Months Ended June 30, 2016 Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of June 30, 2016 (5)(6) Total Gains (Losses) (Realized/Unrealized) Balance, March 31, 2016 Included in Net Income Included in Total Other Comprehensive Income (Loss) (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 Transfers into Level 3 Balance, June 30, 2016 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 25 $ — $ — $ — $ — $ — $ (1 ) $ (24 ) $ — $ — $ — Other agency 1 — — — — — — (1 ) — — — Alt-A and subprime private-label securities 288 27 — — — — (12 ) — — 303 27 Mortgage revenue bonds 363 17 — — (184 ) — (3 ) — — 193 6 Total trading securities $ 677 $ 44 (6)(7) $ — $ — $ (184 ) $ — $ (16 ) $ (25 ) $ — $ 496 $ 33 Available-for-sale securities: Mortgage-related: Fannie Mae $ 1 $ — $ — $ — $ — $ — $ — $ (1 ) $ — $ — $ — Other agency 2 — — — — — — (1 ) — 1 — Alt-A and subprime private-label securities 399 1 9 — — — (61 ) — — 348 — Mortgage revenue bonds 2,564 76 18 — (568 ) — (61 ) — — 2,029 — Other 655 3 (1 ) — (201 ) — (6 ) — — 450 — Total available-for-sale securities $ 3,621 $ 80 (7)(8) $ 26 $ — $ (769 ) $ — $ (128 ) $ (2 ) $ — $ 2,828 $ — Mortgage loans $ 1,311 $ 15 (6)(7) $ — $ 25 $ — $ — $ (67 ) $ (19 ) $ 15 $ 1,280 $ 10 Net derivatives 231 52 (6) — — — (3 ) (33 ) — 1 248 41 Long-term debt: Of Fannie Mae: Senior floating $ (395 ) $ (15 ) $ — $ — $ — $ — $ — $ — $ — $ (410 ) $ (15 ) Of consolidated trusts (246 ) (7 ) — — — (47 ) 9 8 (43 ) (326 ) (7 ) Total long-term debt $ (641 ) $ (22 ) (6) $ — $ — $ — $ (47 ) $ 9 $ 8 $ (43 ) $ (736 ) $ (22 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Six Months Ended June 30, 2016 Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of June 30, 2016 (5)(6) Total Gains (Losses) (Realized/Unrealized) Balance, December 31, 2015 Included in Net Income Included in Total Other Comprehensive Income (Loss) (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 (4) Transfers into Level 3 Balance, June 30, 2016 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ — $ — $ — $ — $ — $ — $ (1 ) $ (24 ) $ 25 $ — $ — Other agency — — — — — — — (1 ) 1 — — Alt-A and subprime private-label securities 949 (64 ) — — (187 ) — (32 ) (363 ) — 303 (40 ) Mortgage revenue bonds 449 29 — — (279 ) — (6 ) — — 193 10 Total trading securities $ 1,398 $ (35 ) (6)(7) $ — $ — $ (466 ) $ — $ (39 ) $ (388 ) $ 26 $ 496 $ (30 ) Available-for-sale securities: Mortgage-related: Fannie Mae $ — $ — $ — $ — $ — $ — $ — $ (1 ) $ 1 $ — $ — Other agency 4 — — — — — — (3 ) — 1 — Alt-A and subprime private-label securities 4,322 104 (159 ) — (875 ) — (205 ) (2,839 ) — 348 — Mortgage revenue bonds 2,701 80 48 — (611 ) — (189 ) — — 2,029 — Other 1,404 — (26 ) — (605 ) — (39 ) (284 ) — 450 — Total available-for-sale securities $ 8,431 $ 184 (7)(8) $ (137 ) $ — $ (2,091 ) $ — $ (433 ) $ (3,127 ) $ 1 $ 2,828 $ — Mortgage loans $ 1,477 $ 116 (6)(7) $ — $ 25 $ (320 ) $ — $ (139 ) $ (84 ) $ 205 $ 1,280 $ 20 Net derivatives 157 232 (6) — — — (7 ) (133 ) (2 ) 1 248 76 Long-term debt: Of Fannie Mae: Senior floating $ (369 ) $ (41 ) $ — $ — $ — $ — $ — $ — $ — $ (410 ) $ (41 ) Of consolidated trusts (496 ) (75 ) — — — (54 ) 318 45 (64 ) (326 ) (8 ) Total long-term debt $ (865 ) $ (116 ) (6) $ — $ — $ — $ (54 ) $ 318 $ 45 $ (64 ) $ (736 ) $ (49 ) __________ (1) Gains (losses) included in other comprehensive income (loss) are included in “Changes in unrealized gains on AFS securities, net of reclassification adjustments and taxes” in our condensed consolidated statements of operations and comprehensive income. (2) Purchases and sales include activity related to the consolidation and deconsolidation of assets of securitization trusts. (3) Issues and settlements include activity related to the consolidation and deconsolidation of liabilities of securitization trusts. (4) Transfers into Level 3 during the second quarter and first half of 2017 consisted primarily of a Fannie Mae security backed by private-label mortgage-related securities. Prices for this security were based on inputs that were not readily available. Transfers out of Level 3 during the first half of 2016 consisted primarily of private-label mortgage-related securities backed by Alt-A loans and subprime loans. Prices for these securities were available from multiple third-party vendors and demonstrated an increased and sustained level of observability over time. (5) Amount represents temporary changes in fair value. Amortization, accretion and OTTI are not considered unrealized and are not included in this amount. (6) Gains (losses) are included in “ Fair value losses, net ” in our condensed consolidated statements of operations and comprehensive income. (7) Gains (losses) are included in “ Net interest income ” in our condensed consolidated statements of operations and comprehensive income. (8) Gains (losses) are included in “ Investment gains, net ” in our condensed consolidated statements of operations and comprehensive income.
Valuation Techniques and Significant Unobservable Inputs for Level 3 Assets and Liabilities [Table Text Block]	The following tables display valuation techniques and the range and the weighted average of significant unobservable inputs for our Level 3 assets and liabilities measured at fair value on a recurring basis. Fair Value Measurements as of June 30, 2017 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Recurring fair value measurements: Trading securities: Mortgage-related securities: Agency (2) $ 1,815 Single Vendor Prepayment Speed (%) 0.0 - 177.0 170.4 Spreads (bps) 32.7 - 210.0 186.0 56 Various Total agency 1,871 Alt-A and subprime private-label securities 264 Consensus Mortgage revenue bonds 1 Various Total trading securities $ 2,136 Available-for-sale securities: Mortgage-related securities: Agency (2) $ 206 Various Alt-A and subprime private-label securities 178 Various Mortgage revenue bonds 656 Single Vendor Spreads (bps) 4.5 - 366.8 58.1 145 Discounted Cash Flow Spreads (bps) 4.5 - 413.3 193.6 72 Various Total mortgage revenue bonds 873 Other 309 Discounted Cash Flow Default Rate (%) 1.2 1.2 Prepayment Speed (%) 0.5 0.5 Severity (%) 95.0 95.0 Spreads (bps) 102.0 - 610.0 604.4 71 Various Total other 380 Total available-for-sale securities $ 1,637 Fair Value Measurements as of June 30, 2017 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Mortgage loans: Single-family $ 509 Build-Up 398 Consensus 51 Various Total single-family 958 Multifamily 161 Build-Up Spreads (bps) 47.0 - 293.2 129.1 Total mortgage loans $ 1,119 Net derivatives $ 121 Dealer Mark 3 Various Total net derivatives $ 124 Long-term debt: Of Fannie Mae: Senior floating $ (365 ) Discounted Cash Flow Of consolidated trusts (3) (543 ) Discounted Cash Flow Default Rate (%) 4.0 - 5.0 4.5 Prepayment Speed (%) 5.0 - 100.0 99.5 Severity (%) 64.0 - 69.0 66.5 Spreads (bps) 43.0 - 656.0 91.6 (217 ) Various Total of consolidated trusts (760 ) Total long-term debt $ (1,125 ) Fair Value Measurements as of December 31, 2016 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Recurring fair value measurements: Trading securities: Mortgage-related securities: Agency (2) $ 809 Consensus 26 Various Total agency 835 Alt-A and subprime private-label securities 232 Consensus Default Rate (%) 0.4 - 10.9 8.2 Prepayment Speed (%) 4.3 - 7.4 6.6 Severity (%) 71.0 - 95.0 88.9 Spreads (bps) 244.6 - 253.9 251.5 39 Consensus Total Alt-A and subprime private-label securities 271 Mortgage revenue bonds 19 Discounted Cash Flow Spreads (bps) 13.0 - 268.2 252.2 2 Various Total mortgage revenue bonds 21 Total trading securities $ 1,127 Available-for-sale securities: Mortgage-related securities: Agency (2) $ 129 Single Vendor Prepayment Speed (%) 124.8 - 165.5 142.4 Spreads (bps) 175.0 - 210.0 182.5 72 Consensus 34 Various Total agency 235 Alt-A and subprime private-label securities 93 Single Vendor Default Rate (%) 2.5 - 8.0 3.8 Prepayment Speed (%) 3.0 - 11.0 4.9 Severity (%) 38.0 - 80.0 48.1 Spreads (bps) 266.1 - 306.8 297.1 45 Discounted Cash Flow Spreads (bps) 361.0 - 450.0 406.0 79 Various Total Alt-A and subprime private-label securities 217 Mortgage revenue bonds 684 Single Vendor Spreads (bps) (16.8 ) - 336.9 44.3 126 Single Vendor 435 Discounted Cash Flow Spreads (bps) (16.8 ) - 391.1 260.0 27 Various Total mortgage revenue bonds 1,272 Other 47 Consensus Default Rate (%) 0.5 - 3.5 3.5 Prepayment Speed (%) 2.5 - 6.0 2.5 Severity (%) 20.0 - 88.0 87.5 Spreads (bps) 221.6 - 300.2 237.7 348 Discounted Cash Flow Default Rate (%) 2.3 2.3 Prepayment Speed (%) 0.5 0.5 Severity (%) 95.0 95.0 Spreads (bps) 190.0 - 450.0 449.1 34 Various Total other 429 Total available-for-sale securities $ 2,153 Fair Value Measurements as of December 31, 2016 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Mortgage loans: Single-family $ 516 Build-Up 300 Consensus 218 Various Total single-family 1,034 Multifamily 163 Build-Up Spreads (bps) 55.0 - 305.2 140.2 Total mortgage loans $ 1,197 Net derivatives $ 10 Internal Model 89 Dealer Mark 21 Discounted Cash Flow (76 ) Various Total net derivatives $ 44 Long-term debt: Of Fannie Mae: Senior floating $ (347 ) Discounted Cash Flow Of consolidated trusts (241 ) Various Total long-term debt $ (588 ) _________ (1) Valuation techniques for which no unobservable inputs are disclosed generally reflect the use of third-party pricing services or dealers, and the range of unobservable inputs applied by these sources is not readily available or cannot be reasonably estimated. Where we have disclosed unobservable inputs for consensus and single vendor techniques, those inputs are based on our validations performed at the security level using discounted cash flows. The prepayment speed used for trading agency securities and available-for-sale agency securities is the Public Securities Association prepayment speed, which can be greater than 100%. For all other securities, the Conditional Prepayment Rate is used as the prepayment speed, which can be between 0% and 100%. (2) Includes Fannie Mae and Freddie Mac securities. (3) Includes instruments for which the prepayment speed represents the estimated annualized rate of prepayment after all prepayment penalty provisions have expired and also instruments for which prepayment speed represents the estimated rate of prepayment over the remaining life of the instrument.
Level 3 Assets Measured on Nonrecurring Basis [Table Text Block]	The following table displays valuation techniques for our Level 3 assets measured at fair value on a nonrecurring basis. The significant unobservable inputs related to these techniques primarily relate to collateral dependent valuations. The related ranges and weighted averages are not meaningful when aggregated as they vary significantly from property to property. Fair Value Measurements as of Valuation Techniques June 30, 2017 December 31, 2016 (Dollars in millions) Nonrecurring fair value measurements: Mortgage loans held for sale, at lower of cost or fair value Consensus $ 2,316 $ 1,025 Single Vendor 74 54 Various 2 9 Total mortgage loans held for sale, at lower of cost or fair value 2,392 1,088 Single-family mortgage loans held for investment, at amortized cost Internal Model 1,806 2,816 Multifamily mortgage loans held for investment, at amortized cost Broker Price Opinions 19 25 Asset Manager Estimate 96 170 Various — 3 Total multifamily mortgage loans held for investment, at amortized cost 115 198 Acquired property, net: (1) Single-family Accepted Offers 255 340 Appraisals 509 571 Walk Forwards 200 306 Internal Model 294 476 Various 44 99 Total single-family 1,302 1,792 Multifamily Broker Price Opinions 27 — Other assets Various 2 12 Total nonrecurring assets at fair value $ 5,644 $ 5,906 __________ (1) The most commonly used techniques in our valuation of acquired property are proprietary home price model and third-party valuations (both current and walk forward). Based on the number of properties measured as of June 30, 2017 , these methodologies comprised approximately 74% of our valuations, while accepted offers comprised approximately 20% of our valuations. Based on the number of properties measured as of December 31, 2016, these methodologies comprised approximately 75% of our valuations, while accepted offers comprised approximately 19% of our valuations.
Fair Value of Financial Instruments [Table Text Block]	The following table displays the carrying value and estimated fair value of our financial instruments. The fair value of financial instruments we disclose includes commitments to purchase multifamily and single-family mortgage loans that we do not record in our condensed consolidated balance sheets. The fair values of these commitments are included as “Mortgage loans held for investment, net of allowance for loan losses.” The disclosure excludes all non-financial instruments; therefore, the fair value of our financial assets and liabilities does not represent the underlying fair value of our total consolidated assets and liabilities. As of June 30, 2017 Carrying Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Netting Adjustment Estimated (Dollars in millions) Financial assets: Cash and cash equivalents and restricted cash $ 47,903 $ 36,003 $ 11,900 $ — $ — $ 47,903 Federal funds sold and securities purchased under agreements to resell or similar arrangements 29,220 — 29,220 — — 29,220 Trading securities 39,274 32,418 4,720 2,136 — 39,274 Available-for-sale securities 6,408 — 4,771 1,637 — 6,408 Mortgage loans held for sale 5,322 — 3,193 2,897 — 6,090 Mortgage loans held for investment, net of allowance for loan losses 3,120,093 — 2,828,761 322,070 — 3,150,831 Advances to lenders 4,965 — 4,659 322 — 4,981 Derivative assets at fair value 419 — 4,276 167 (4,024 ) 419 Guaranty assets and buy-ups 148 — — 433 — 433 Total financial assets $ 3,253,752 $ 68,421 $ 2,891,500 $ 329,662 $ (4,024 ) $ 3,285,559 Financial liabilities: Federal funds purchased and securities sold under agreements to repurchase $ 7 $ — $ 7 $ — $ — $ 7 Short-term debt: Of Fannie Mae 30,501 — 30,501 — — 30,501 Of consolidated trusts 511 — — 511 — 511 Long-term debt: Of Fannie Mae 272,619 — 280,471 812 — 281,283 Of consolidated trusts 2,984,036 — 2,954,716 40,513 — 2,995,229 Derivative liabilities at fair value 420 — 5,411 43 (5,034 ) 420 Guaranty obligations 264 — — 523 — 523 Total financial liabilities $ 3,288,358 $ — $ 3,271,106 $ 42,402 $ (5,034 ) $ 3,308,474 As of December 31, 2016 Carrying Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Netting Adjustment Estimated (Dollars in millions) Financial assets: Cash and cash equivalents and restricted cash $ 62,177 $ 41,477 $ 20,700 $ — $ — $ 62,177 Federal funds sold and securities purchased under agreements to resell or similar arrangements 30,415 — 30,415 — — 30,415 Trading securities 40,562 32,317 7,118 1,127 — 40,562 Available-for-sale securities 8,363 — 6,210 2,153 — 8,363 Mortgage loans held for sale 2,899 — 509 2,751 — 3,260 Mortgage loans held for investment, net of allowance for loan losses 3,076,854 — 2,767,813 316,742 — 3,084,555 Advances to lenders 7,494 — 7,156 352 — 7,508 Derivative assets at fair value 687 — 5,019 182 (4,514 ) 687 Guaranty assets and buy-ups 158 — — 432 — 432 Total financial assets $ 3,229,609 $ 73,794 $ 2,844,940 $ 323,739 $ (4,514 ) $ 3,237,959 Financial liabilities: Short-term debt: Of Fannie Mae $ 34,995 $ — $ 34,998 $ — $ — $ 34,998 Of consolidated trusts 584 — — 584 — 584 Long-term debt: Of Fannie Mae 292,102 — 298,980 770 — 299,750 Of consolidated trusts 2,934,635 — 2,901,316 36,668 — 2,937,984 Derivative liabilities at fair value 1,215 — 7,921 138 (6,844 ) 1,215 Guaranty obligations 280 — — 710 — 710 Total financial liabilities $ 3,263,811 $ — $ 3,243,215 $ 38,870 $ (6,844 ) $ 3,275,241
Fair Value Option [Table Text Block]	The following table displays the fair value and unpaid principal balance of the financial instruments for which we have made fair value elections. As of June 30, 2017 December 31, 2016 Loans (1) Long-Term Debt of Fannie Mae Long-Term Debt of Consolidated Trusts Loans (1) Long-Term Debt of Fannie Mae Long-Term Debt of Consolidated Trusts (Dollars in millions) Fair value $ 11,406 $ 9,008 $ 34,866 $ 12,057 $ 9,582 $ 36,524 Unpaid principal balance 10,980 8,167 31,510 11,688 9,090 33,055 __________ (1) Includes nonaccrual loans with a fair value of $187 million and $200 million as of June 30, 2017 and December 31, 2016 , respectively. The difference between unpaid principal balance and the fair value of these nonaccrual loans as of June 30, 2017 and December 31, 2016 was $33 million and $34 million , respectively. Includes loans that are 90 days or more past due with a fair value of $145 million and $152 million as of June 30, 2017 and December 31, 2016 , respectively. The difference between unpaid principal balance and the fair value of these 90 or more days past due loans as of June 30, 2017 and December 31, 2016 was $25 million . The following tables display fair value gains and losses, net, including changes attributable to instrument-specific credit risk, for loans and debt for which the fair value election was made. Amounts are recorded as a component of “ Fair value losses, net ” in our condensed consolidated statements of operations and comprehensive income. For the Three Months Ended June 30, 2017 2016 Loans Long-Term Debt Total Gains (Losses) Loans Long-Term Debt Total Gains (Losses) (Dollars in millions) Changes in instrument-specific credit risk $ 26 $ (173 ) $ (147 ) $ 19 $ (169 ) $ (150 ) Other changes in fair value 68 (115 ) (47 ) 126 (144 ) (18 ) Fair value gains (losses), net $ 94 $ (288 ) $ (194 ) $ 145 $ (313 ) $ (168 ) For the Six Months Ended June 30, 2017 2016 Loans Long-Term Debt Total Gains (Losses) Loans Long-Term Debt Total Gains (Losses) (Dollars in millions) Changes in instrument-specific credit risk $ 53 $ (339 ) $ (286 ) $ 32 $ (221 ) $ (189 ) Other changes in fair value 83 (118 ) (35 ) 344 (446 ) (102 ) Fair value gains (losses), net $ 136 $ (457 ) $ (321 ) $ 376 $ (667 ) $ (291 )

Summary of Significant Accoun46

Summary of Significant Accounting Policies Regulatory Capital (Details) - USD ($) $ in Billions	Jun. 30, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Deficit of core capital over statutory minimum capital requirement	$ 137.9	$ 136.2

Summary of Significant Accoun47

Summary of Significant Accounting Policies Related Parties (Details) - USD ($) $ / shares in Units, $ in Millions	Jun. 30, 2017	Sep. 30, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2016	Sep. 08, 2008	Jun. 04, 2008
Related Parties [Line Items]
Number of days after which we have not been paying debts or liabilities exceed assets FHFA must place us into receivership					60 days
Preferred Stock, Shares Issued	555,374,922		555,374,922		555,374,922				555,374,922		1,000,000
Senior Preferred Stock, Par or Stated Value Per Share										$ 1,000
Payments of cash dividends on senior preferred stock to Treasury	$ 2,800				$ 8,250	$ 3,778
Net worth								$ 3,400
Stockholders' Equity Attributable to Parent	3,717		$ 3,717		3,717				$ 6,071
Income Taxes Paid			1,100	$ 250	1,070	610
Unpaid principal balance guaranteed by a related party	$ 5,200		5,200		5,200
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees			$ 518	453	$ 1,021	893
Basis Points of Each Dollar of Unpaid Principal Balance	0.042%		0.042%		0.042%
Trading, at fair value (includes $1,007 and $1,277, respectively, pledged as collateral )	$ 39,274		$ 39,274		$ 39,274				40,562
Interest Receivable	7,840		7,840		7,840				7,737
Interest income recognized on Treasury securities			176	128	318	248
Scenario, Forecast [Member]
Related Parties [Line Items]
Expected undeclared dividends payable on senior preferred stock for the next quarter		$ 3,100
US Treasury [Member]
Related Parties [Line Items]
Total available funding from US Treasury pursuant to the senior preferred stock agreement	117,600		117,600		117,600
Capital Reserve Amount, Prior year, Senior Preferred Stock Purchase Agreement, Amendment									1,200
Capital Reserve Amount, current year, Senior Preferred Stock Purchase Agreement, Amendment	600		600		600
Aggregate funding received from US Treasury pursuant to the senior preferred stock purchase agreement	116,100		116,100		116,100				116,100
Aggregate liquidation preference of senior preferred stock	$ 117,100		$ 117,100		$ 117,100
Percentage of common shares attributable to warrants issued to US Treasury as percentage to total diluted common shares	79.90%		79.90%		79.90%
Home Affordable Modification Program administrative expense reimbursements from Treasury and Freddie Mac			$ 11	15	$ 23	31
Percentage of initial principal loss US Treasury will bear for New Issue Bond Program	35.00%		35.00%		35.00%
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees			$ 518	453	$ 1,021	893
US Treasury [Member] | Single-family [Member]
Related Parties [Line Items]
Recognized TCCA fees that had not been remitted to Treasury as of period end	$ 518		518		518
US Treasury [Member] | Scenario, Forecast [Member]
Related Parties [Line Items]
Capital Reserve Amount, Fiscal Year, Senior Preferred Stock Purchase Agreement, Amendment							$ 0
Freddie Mac [Member] | Freddie Mac [Member]
Related Parties [Line Items]
Interest Receivable	3		3		3				5
Fair value of mortgage-related securities	748		748		748				1,400
Interest income recognized on mortgage-related securities			10	36	23	81
Federal Housing Finance Agency [Member]
Related Parties [Line Items]
FHFA assessment fees			26	28	56	56
Common Securitization Solutions [Member]
Related Parties [Line Items]
Payments to Acquire or Advance to Equity Method Investments			18	35	53	65
U.S. Treasury securities [Member]
Related Parties [Line Items]
Trading, at fair value (includes $1,007 and $1,277, respectively, pledged as collateral )	32,418		32,418		32,418				32,317
U.S. Treasury securities [Member] | US Treasury [Member]
Related Parties [Line Items]
Trading, at fair value (includes $1,007 and $1,277, respectively, pledged as collateral )	32,400		32,400		32,400				32,300
Interest Receivable	63		63		63				$ 39
Interest income recognized on Treasury securities			86	33	149	65
Other Expense [Member] | US Treasury [Member]
Related Parties [Line Items]
Affordable Housing Program Assessments			29	$ 31	58	$ 56
Recognized affordable housing program expenses that had not been remitted to Treasury as of period end	$ 58		$ 58		$ 58

Consolidations and Transfers 48

Consolidations and Transfers of Financial Assets Unconsolidated VIEs (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Variable Interest Entities [Line Items]
Trading, at fair value	$ 39,274	$ 40,562
Available-for-sale, at fair value	6,408	8,363
Other assets	18,072	20,942
Other liabilities	(8,373)	(10,150)
Unpaid principal balance of mortgage loans	3,105,954	3,063,646
Multifamily [Member]
Variable Interest Entities [Line Items]
Unpaid principal balance of mortgage loans	244,701	229,896
Unconsolidated VIEs [Member] | Multifamily [Member]
Variable Interest Entities [Line Items]
Unpaid principal balance of mortgage loans	244,700
Unconsolidated VIEs [Member] | Mortgage-related securities [Member]
Variable Interest Entities [Line Items]
Trading, at fair value	6,774	8,115
Available-for-sale, at fair value	5,493	7,326
Other assets	74	77
Other liabilities	(501)	(528)
Net carrying amount	11,840	14,990
Maximum exposure to loss	17,000	21,000
Total unconsolidated assets	100,000	150,000
Unconsolidated VIEs [Member] | Partnership interest [Member]
Variable Interest Entities [Line Items]
Net carrying amount	83	92
Maximum exposure to loss	108	118
Total unconsolidated assets	3,600	3,900
Unconsolidated VIEs [Member] | Fannie Mae Securities [Member]
Variable Interest Entities [Line Items]
Trading, at fair value	4,197	4,642
Available-for-sale, at fair value	2,174	2,447
Unconsolidated VIEs [Member] | Non-Fannie Mae Securities [Member]
Variable Interest Entities [Line Items]
Trading, at fair value	2,577	3,473
Available-for-sale, at fair value	$ 3,319	$ 4,879

Consolidations and Transfers 49

Consolidations and Transfers of Financial Assets Transfers of Financial Assets (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Transfers of Financial Assets [Line Items]
Portfolio securitizations: unpaid principal balance	$ 69,200	$ 64,300	$ 126,500	$ 112,600
Unconsolidated VIEs [Member]
Transfers of Financial Assets [Line Items]
Retained interests: principal and interest received	303	$ 315	560	$ 623
Unconsolidated VIEs [Member] | Single Class MBS, REMIC & Megas [Member]
Transfers of Financial Assets [Line Items]
Retained interests: unpaid principal balance	4,100		4,100		$ 4,400
Retained interests: fair value	$ 5,200		$ 5,200		$ 5,800

Consolidations and Transfers 50

Consolidations and Transfers of Financial Assets Managed Loans (Details) - USD ($) $ in Billions	Jun. 30, 2017	Dec. 31, 2016
Consolidations and Transfers of Financial Assets [Abstract]
Securitized loans in unconsolidated portfolio securitization trusts: unpaid principal balance	$ 1.3	$ 1.4

Mortgage Loans Loans in Mortgag

Mortgage Loans Loans in Mortgage Portfolio (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	$ 3,105,954		$ 3,105,954			$ 3,063,646
Cost basis and fair value adjustments, net	39,860		39,860			39,572
Allowance for loan losses for loans held for investment	(20,399)	$ (23,799)	(20,399)	$ (23,799)	$ (22,129)	(23,465)	$ (25,819)	$ (27,951)
Total mortgage loans	3,125,415		3,125,415			3,079,753
Carrying value of loans redesignated from HFI to HFS	2,900	1,000	5,400	1,600
Carrying value of loans redesignated from HFS to HFI	17		52
Sale of loans, unpaid principal balance	2,900	$ 1,500	3,000	$ 2,600
Single-family [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	2,861,253		2,861,253			2,833,750
Recorded investment of single-family mortgage loans referred to foreclosure	15,600		15,600			18,300
Multifamily [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	$ 244,701		$ 244,701			$ 229,896

Mortgage Loans Aging (Details)

Mortgage Loans Aging (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	$ 62,556	$ 74,222
Current	3,074,173	3,021,594
Total recorded investment in loans	3,136,729	3,095,816
Recorded investment in loans 90 days or more delinquent and accruing interest	253	285
Recorded investment in nonaccrual loans	35,251	42,108
30 to 59 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	31,615	36,709
60 to 89 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	8,065	9,564
Seriously Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	22,876	27,949
Single-family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	62,434	74,049
Current	2,827,667	2,789,886
Total recorded investment in loans	2,890,101	2,863,935
Recorded investment in loans 90 days or more delinquent and accruing interest	253	285
Recorded investment in nonaccrual loans	$ 34,910	$ 41,705
Single-family [Member] | Minimum [Member]
Table Footnote [Abstract]
Serious delinquency, days past due	90 days	90 days
Single-family [Member] | 30 to 59 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	$ 31,588	$ 36,665
Single-family [Member] | 60 to 89 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	8,065	9,564
Single-family [Member] | Seriously Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	22,781	27,820
Single-family [Member] | Primary [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	51,813	61,302
Current	2,703,162	2,654,195
Total recorded investment in loans	2,754,975	2,715,497
Recorded investment in loans 90 days or more delinquent and accruing interest	19	22
Recorded investment in nonaccrual loans	28,056	33,448
Single-family [Member] | Primary [Member] | 30 to 59 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	27,294	31,631
Single-family [Member] | Primary [Member] | 60 to 89 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	6,677	7,910
Single-family [Member] | Primary [Member] | Seriously Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	17,842	21,761
Single-family [Member] | Government [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	300	334
Current	35,080	36,814
Total recorded investment in loans	35,380	37,148
Recorded investment in loans 90 days or more delinquent and accruing interest	228	256
Recorded investment in nonaccrual loans	1	0
Single-family [Member] | Government [Member] | 30 to 59 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	50	56
Single-family [Member] | Government [Member] | 60 to 89 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	21	22
Single-family [Member] | Government [Member] | Seriously Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	229	256
Single-family [Member] | Alt-A [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	7,554	9,044
Current	66,845	72,903
Total recorded investment in loans	74,399	81,947
Recorded investment in loans 90 days or more delinquent and accruing interest	2	2
Recorded investment in nonaccrual loans	5,026	6,019
Single-family [Member] | Alt-A [Member] | 30 to 59 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	3,103	3,629
Single-family [Member] | Alt-A [Member] | 60 to 89 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	1,000	1,194
Single-family [Member] | Alt-A [Member] | Seriously Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	3,451	4,221
Single-family [Member] | Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	2,767	3,369
Current	22,580	25,974
Total recorded investment in loans	25,347	29,343
Recorded investment in loans 90 days or more delinquent and accruing interest	4	5
Recorded investment in nonaccrual loans	1,827	2,238
Single-family [Member] | Other [Member] | 30 to 59 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	1,141	1,349
Single-family [Member] | Other [Member] | 60 to 89 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	367	438
Single-family [Member] | Other [Member] | Seriously Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	1,259	1,582
Multifamily [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	122	173
Current	246,506	231,708
Total recorded investment in loans	246,628	231,881
Recorded investment in loans 90 days or more delinquent and accruing interest	0	0
Recorded investment in nonaccrual loans	$ 341	$ 403
Multifamily [Member] | Minimum [Member]
Table Footnote [Abstract]
Serious delinquency, days past due	60 days	60 days
Multifamily [Member] | Maximum [Member]
Table Footnote [Abstract]
Serious delinquency, days past due	89 days	89 days
Multifamily [Member] | 30 to 59 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	$ 27	$ 44
Multifamily [Member] | Seriously Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	$ 95	$ 129

Mortgage Loans Credit Quality I

Mortgage Loans Credit Quality Indicators - SF (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	$ 3,136,729	$ 3,095,816
Single-family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	2,890,101	2,863,935
Single-family [Member] | Primary [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	2,754,975	2,715,497
Single-family [Member] | Primary [Member] | Estimated mark-to-market loan-to-value ratio less than or equal to 80% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	2,410,185	2,321,201
Single-family [Member] | Primary [Member] | Estimated mark-to-market loan-to-value ratio greater than 80% and less than or equal to 90% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	231,412	244,231
Single-family [Member] | Primary [Member] | Estimated mark-to-market loan-to-value ratio greater than 90% and less than or equal to 100% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	88,637	114,412
Single-family [Member] | Primary [Member] | Estimated mark-to-market loan-to-value ratio greater than 100% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	24,741	35,653
Single-family [Member] | Alt-A [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	74,399	81,947
Single-family [Member] | Alt-A [Member] | Estimated mark-to-market loan-to-value ratio less than or equal to 80% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	54,917	56,250
Single-family [Member] | Alt-A [Member] | Estimated mark-to-market loan-to-value ratio greater than 80% and less than or equal to 90% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	8,010	9,787
Single-family [Member] | Alt-A [Member] | Estimated mark-to-market loan-to-value ratio greater than 90% and less than or equal to 100% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	5,088	6,731
Single-family [Member] | Alt-A [Member] | Estimated mark-to-market loan-to-value ratio greater than 100% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	6,384	9,179
Single-family [Member] | Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	25,347	29,343
Single-family [Member] | Other [Member] | Estimated mark-to-market loan-to-value ratio less than or equal to 80% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	18,219	19,382
Single-family [Member] | Other [Member] | Estimated mark-to-market loan-to-value ratio greater than 80% and less than or equal to 90% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	2,826	3,657
Single-family [Member] | Other [Member] | Estimated mark-to-market loan-to-value ratio greater than 90% and less than or equal to 100% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	1,908	2,627
Single-family [Member] | Other [Member] | Estimated mark-to-market loan-to-value ratio greater than 100% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	2,394	3,677
Single-family [Member] | Government [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	$ 35,380	$ 37,148

Mortgage Loans Credit Quality54

Mortgage Loans Credit Quality Indicators - MF (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	$ 3,136,729	$ 3,095,816
Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	246,628	231,881
Multifamily [Member] | Non-Classified [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	243,555	228,749
Multifamily [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	3,069	3,129
Multifamily [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	4	3
Multifamily [Member] | Total classified [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	$ 3,073	$ 3,132

Mortgage Loans Individually Imp

Mortgage Loans Individually Impaired Loans (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	$ 133,412	$ 145,421
Individually impaired loans with related allowance recorded: total recorded investment	125,762	136,977
Related allowance for loan losses	19,238	21,953
Individually impaired loans with no related allowance recorded: unpaid principal balance	20,940	20,732
Individually impaired loans with no related allowance recorded: total recorded investment	19,558	19,210
Total individually impaired loans: unpaid principal balance	154,352	166,153
Total individually impaired loans: total recorded investment	145,320	156,187
Single-family [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	133,195	145,101
Individually impaired loans with related allowance recorded: total recorded investment	125,544	136,654
Related allowance for loan losses	19,197	21,920
Individually impaired loans with no related allowance recorded: unpaid principal balance	20,672	20,466
Individually impaired loans with no related allowance recorded: total recorded investment	19,289	18,944
Single-family [Member] | Primary [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	97,394	105,113
Individually impaired loans with related allowance recorded: total recorded investment	92,591	99,825
Related allowance for loan losses	12,778	14,462
Individually impaired loans with no related allowance recorded: unpaid principal balance	16,109	15,733
Individually impaired loans with no related allowance recorded: total recorded investment	15,225	14,758
Single-family [Member] | Government [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	288	302
Individually impaired loans with related allowance recorded: total recorded investment	291	305
Related allowance for loan losses	58	59
Individually impaired loans with no related allowance recorded: unpaid principal balance	67	63
Individually impaired loans with no related allowance recorded: total recorded investment	62	59
Single-family [Member] | Alt-A [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	25,862	28,599
Individually impaired loans with related allowance recorded: total recorded investment	23,556	26,059
Related allowance for loan losses	4,642	5,365
Individually impaired loans with no related allowance recorded: unpaid principal balance	3,418	3,511
Individually impaired loans with no related allowance recorded: total recorded investment	3,010	3,062
Single-family [Member] | Other [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	9,651	11,087
Individually impaired loans with related allowance recorded: total recorded investment	9,106	10,465
Related allowance for loan losses	1,719	2,034
Individually impaired loans with no related allowance recorded: unpaid principal balance	1,078	1,159
Individually impaired loans with no related allowance recorded: total recorded investment	992	1,065
Multifamily [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	217	320
Individually impaired loans with related allowance recorded: total recorded investment	218	323
Related allowance for loan losses	41	33
Individually impaired loans with no related allowance recorded: unpaid principal balance	268	266
Individually impaired loans with no related allowance recorded: total recorded investment	$ 269	$ 266

Mortgage Loans Individually I56

Mortgage Loans Individually Impaired Loans - 2 (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	$ 128,821	$ 147,087	$ 131,674	$ 149,007
Individually impaired loans with related allowance recorded: total interest income recognized	1,283	1,380	2,610	2,754
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	96	85	204	216
Individually impaired loans with no related allowance recorded: average recorded investment	19,478	20,249	19,486	20,209
Individually impaired loans with no related allowance recorded: total interest income recognized	369	442	758	798
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	27	37	54	61
Individually impaired loans: average recorded investment	148,299	167,336	151,160	169,216
Individually impaired loans: total interest income recognized	1,652	1,822	3,368	3,552
Individually impaired loans: interest income recognized on a cash basis	123	122	258	277
Table Footnote [Abstract]
Individually impaired loans: total interest income recognized	1,652	1,822	3,368	3,552
Single-family [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	128,562	146,531	131,394	148,418
Individually impaired loans with related allowance recorded: total interest income recognized	1,279	1,367	2,604	2,736
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	96	85	204	216
Individually impaired loans with no related allowance recorded: average recorded investment	19,194	19,923	19,208	19,874
Individually impaired loans with no related allowance recorded: total interest income recognized	362	439	748	792
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	27	37	54	61
Individually impaired loans: total interest income recognized	1,700	1,800	3,400	3,500
Table Footnote [Abstract]
Troubled debt restructuring recorded investment	144,300		144,300		$ 155,000
Individually impaired loans: total interest income recognized	1,700	1,800	3,400	3,500
Individually impaired loans: contractual interest income	1,500	1,500	2,900	2,900
Individually impaired loans: effective yield adjustments	229	331	497	641
Single-family [Member] | Primary [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	94,599	106,674	96,395	107,984
Individually impaired loans with related allowance recorded: total interest income recognized	955	1,015	1,941	2,036
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	77	71	165	175
Individually impaired loans with no related allowance recorded: average recorded investment	15,091	15,377	15,050	15,323
Individually impaired loans with no related allowance recorded: total interest income recognized	273	327	562	595
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	24	30	47	50
Single-family [Member] | Government [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	295	317	298	320
Individually impaired loans with related allowance recorded: total interest income recognized	2	3	5	6
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	0	0	0	0
Individually impaired loans with no related allowance recorded: average recorded investment	61	59	61	58
Individually impaired loans with no related allowance recorded: total interest income recognized	1	1	2	2
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	0	0	0	0
Single-family [Member] | Alt-A [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	24,249	27,901	24,896	28,287
Individually impaired loans with related allowance recorded: total interest income recognized	240	256	489	509
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	14	11	29	30
Individually impaired loans with no related allowance recorded: average recorded investment	3,026	3,361	3,056	3,362
Individually impaired loans with no related allowance recorded: total interest income recognized	67	81	140	143
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	2	5	5	8
Single-family [Member] | Other [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	9,419	11,639	9,805	11,827
Individually impaired loans with related allowance recorded: total interest income recognized	82	93	169	185
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	5	3	10	11
Individually impaired loans with no related allowance recorded: average recorded investment	1,016	1,126	1,041	1,131
Individually impaired loans with no related allowance recorded: total interest income recognized	21	30	44	52
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	1	2	2	3
Multifamily [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	259	556	280	589
Individually impaired loans with related allowance recorded: total interest income recognized	4	13	6	18
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	0	0	0	0
Individually impaired loans with no related allowance recorded: average recorded investment	284	326	278	335
Individually impaired loans with no related allowance recorded: total interest income recognized	7	3	10	6
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	0	$ 0	0	$ 0
Table Footnote [Abstract]
Troubled debt restructuring recorded investment	$ 198		$ 198		$ 248

Mortgage Loans TDRs (Details)

Mortgage Loans TDRs (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017USD ($)contracts	Jun. 30, 2016USD ($)contracts	Jun. 30, 2017USD ($)contracts	Jun. 30, 2016USD ($)contracts
Financing Receivable, Modifications [Line Items]
Average term extension of a single-family modified loan	155 months	159 months	154 months	159 months
Average interest rate reduction of a single-family modified loan	0.67%	0.72%	0.80%	0.73%
Number of loans troubled debt restructurings activity | contracts	15,795	16,831	34,965	36,385
Recorded investment troubled debt restructurings activity | $	$ 2,206	$ 2,375	$ 4,852	$ 5,055
Single-family [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity | contracts	15,792	16,827	34,962	36,381
Recorded investment troubled debt restructurings activity | $	$ 2,189	$ 2,330	$ 4,835	$ 5,010
Single-family [Member] | Primary [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity | contracts	14,148	14,814	31,383	32,004
Recorded investment troubled debt restructurings activity | $	$ 1,945	$ 2,028	$ 4,308	$ 4,360
Single-family [Member] | Government [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity | contracts	45	28	106	82
Recorded investment troubled debt restructurings activity | $	$ 4	$ 3	$ 10	$ 9
Single-family [Member] | Alt-A [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity | contracts	1,328	1,623	2,893	3,534
Recorded investment troubled debt restructurings activity | $	$ 194	$ 238	$ 418	$ 508
Single-family [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity | contracts	271	362	580	761
Recorded investment troubled debt restructurings activity | $	$ 46	$ 61	$ 99	$ 133
Multifamily [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity | contracts	3	4	3	4
Recorded investment troubled debt restructurings activity | $	$ 17	$ 45	$ 17	$ 45

Mortgage Loans TDRs with Sub De

Mortgage Loans TDRs with Sub Defaults (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017USD ($)contracts	Jun. 30, 2016USD ($)contracts	Jun. 30, 2017USD ($)contracts	Jun. 30, 2016USD ($)contracts
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings subsequent default | contracts	5,029	5,720	10,343	12,291
Recorded investment troubled debt restructurings subsequent default | $	$ 719	$ 797	$ 1,480	$ 1,794
Single-family [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings subsequent default | contracts			10,342	12,291
Recorded investment troubled debt restructurings subsequent default | $			$ 1,476	$ 1,794
Single-family [Member] | Primary [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings subsequent default | contracts	4,238	4,648	8,717	10,109
Recorded investment troubled debt restructurings subsequent default | $	$ 589	$ 638	$ 1,210	$ 1,440
Single-family [Member] | Government [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings subsequent default | contracts	25	27	44	42
Recorded investment troubled debt restructurings subsequent default | $	$ 3	$ 3	$ 5	$ 5
Single-family [Member] | Alt-A [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings subsequent default | contracts	616	756	1,230	1,608
Recorded investment troubled debt restructurings subsequent default | $	$ 97	$ 116	$ 193	$ 260
Single-family [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings subsequent default | contracts	150	289	351	532
Recorded investment troubled debt restructurings subsequent default | $	$ 30	$ 40	$ 68	$ 89
Multifamily [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings subsequent default | contracts			1	0
Recorded investment troubled debt restructurings subsequent default | $			$ 4	$ 0

Allowance for Loan Losses Rollf

Allowance for Loan Losses Rollforward by Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Allowance for Loan Losses [Roll Forward]
Beginning balance	$ 22,129	$ 25,819	$ 23,465	$ 27,951
Benefit for loan losses	(1,196)	(1,336)	(1,607)	(2,368)
Charge-offs	(689)	(821)	(1,729)	(2,105)
Recoveries	147	115	232	235
Other	8	22	38	86
Ending balance	20,399	23,799	20,399	23,799
Single-family [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	21,938	25,597	23,283	27,709
Benefit for loan losses	(1,185)	(1,332)	(1,605)	(2,348)
Charge-offs	(689)	(818)	(1,729)	(2,097)
Recoveries	146	115	231	234
Other	8	22	38	86
Ending balance	20,218	23,584	20,218	23,584
Multifamily [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	191	222	182	242
Benefit for loan losses	(11)	(4)	(2)	(20)
Charge-offs	0	(3)	0	(8)
Recoveries	1	0	1	1
Ending balance	$ 181	$ 215	$ 181	$ 215

Allowance for Loan Losses and T

Allowance for Loan Losses and Total Recorded Investment in HFI Loans (Details) - USD ($) $ in Millions	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	$ 19,238		$ 21,953
Allowance for loan losses for collectively reserved loans	1,161		1,512
Total allowance for loan losses	20,399	$ 22,129	23,465	$ 23,799	$ 25,819	$ 27,951
Recorded investment in individually impaired loans	145,320		156,187
Recorded investment in collectively reserved loans	2,991,409		2,939,629
Total recorded investment in loans	3,136,729		3,095,816
Single-family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	19,197		21,920
Allowance for loan losses for collectively reserved loans	1,021		1,363
Total allowance for loan losses	20,218	21,938	23,283	23,584	25,597	27,709
Recorded investment in individually impaired loans	144,833		155,598
Recorded investment in collectively reserved loans	2,745,268		2,708,337
Total recorded investment in loans	2,890,101		2,863,935
Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	41		33
Allowance for loan losses for collectively reserved loans	140		149
Total allowance for loan losses	181	$ 191	182	$ 215	$ 222	$ 242
Recorded investment in individually impaired loans	487		589
Recorded investment in collectively reserved loans	246,141		231,292
Total recorded investment in loans	$ 246,628		$ 231,881

Investments in Securities Tradi

Investments in Securities Trading 1 (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	$ 39,274	$ 40,562
Mortgage-related securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	6,856	8,245
Fannie Mae [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	4,277	4,769
Other agency [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	1,969	2,058
Alt-A and subprime private-label securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	593	636
CMBS [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	16	761
Mortgage revenue bonds [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	1	21
U.S. Treasury securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	$ 32,418	$ 32,317

Investments in Securities Avail

Investments in Securities Available-for-sale Securities 1 (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Gross realized gains	$ 227	$ 234	$ 230	$ 445
Gross realized losses	0	8	0	12
Total proceeds (excludes initial sale of securities from new portfolio securitizations)	$ 799	$ 3,645	$ 894	$ 7,267

Investments in Securities Ava63

Investments in Securities Available-for-sale Securities 2 (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	$ 5,419	$ 7,261
Gross unrealized gains	1,021	1,142
Gross unrealized losses	(32)	(40)
Available-for-sale, at fair value	6,408	8,363
Fannie Mae [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	2,173	2,445
Gross unrealized gains	124	137
Gross unrealized losses	(25)	(28)
Available-for-sale, at fair value	2,272	2,554
Other agency [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	399	508
Gross unrealized gains	33	39
Gross unrealized losses	0	0
Available-for-sale, at fair value	432	547
Alt-A and subprime private-label securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	1,335	1,817
Gross unrealized gains	828	895
Gross unrealized losses	(1)	(3)
Available-for-sale, at fair value	2,162	2,709
CMBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	259	815
Gross unrealized gains	0	4
Gross unrealized losses	0	0
Available-for-sale, at fair value	259	819
Mortgage revenue bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	858	1,245
Gross unrealized gains	21	36
Gross unrealized losses	(6)	(9)
Available-for-sale, at fair value	873	1,272
Other mortgage-related securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	395	431
Gross unrealized gains	15	31
Gross unrealized losses	0	0
Available-for-sale, at fair value	$ 410	$ 462

Investments in Securities Ava64

Investments in Securities Available-for-sale Securities 3 (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Consecutive Months, Gross Unrealized Losses	$ (2)	$ (9)
Less than 12 Consecutive Months, Fair Value	194	217
12 Consecutive Months or Longer, Gross Unrealized Losses	(30)	(31)
12 Consecutive Months or Longer, Fair Value	524	556
Fannie Mae [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Consecutive Months, Gross Unrealized Losses	(2)	(2)
Less than 12 Consecutive Months, Fair Value	194	139
12 Consecutive Months or Longer, Gross Unrealized Losses	(23)	(26)
12 Consecutive Months or Longer, Fair Value	443	477
Alt-A and subprime private-label securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Consecutive Months, Gross Unrealized Losses	0	0
Less than 12 Consecutive Months, Fair Value	0	0
12 Consecutive Months or Longer, Gross Unrealized Losses	(1)	(3)
12 Consecutive Months or Longer, Fair Value	64	73
Mortgage revenue bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Consecutive Months, Gross Unrealized Losses	0	(7)
Less than 12 Consecutive Months, Fair Value	0	78
12 Consecutive Months or Longer, Gross Unrealized Losses	(6)	(2)
12 Consecutive Months or Longer, Fair Value	$ 17	$ 6

Investments in Securities Other

Investments in Securities Other-than-temporary Impairments (Details) - USD ($) $ in Billions	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held	$ 1.8	$ 1.8	$ 1.9	$ 2.2	$ 2.3	$ 2.4

Investments in Securities Matur

Investments in Securities Maturity Information (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	$ 5,419	$ 7,261
Total fair value	6,408	8,363
One Year or Less, Amortized Cost	272
One Year or Less, Fair Value	272
After One Year through Five Years, Amortized Cost	114
After One Year through Five Years, Fair Value	115
After Five Years through Ten Years, Amortized Cost	241
After Five Years through Ten Years, Fair Value	251
After Ten Years, Amortized Cost	4,792
After Ten Years, Fair Value	5,770
Fannie Mae [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	2,173	2,445
Total fair value	2,272	2,554
One Year or Less, Amortized Cost	2
One Year or Less, Fair Value	2
After One Year through Five Years, Amortized Cost	13
After One Year through Five Years, Fair Value	14
After Five Years through Ten Years, Amortized Cost	64
After Five Years through Ten Years, Fair Value	68
After Ten Years, Amortized Cost	2,094
After Ten Years, Fair Value	2,188
Other agency [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	399	508
Total fair value	432	547
One Year or Less, Amortized Cost	1
One Year or Less, Fair Value	1
After One Year through Five Years, Amortized Cost	26
After One Year through Five Years, Fair Value	26
After Five Years through Ten Years, Amortized Cost	62
After Five Years through Ten Years, Fair Value	66
After Ten Years, Amortized Cost	310
After Ten Years, Fair Value	339
Alt-A and subprime private-label securities [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	1,335	1,817
Total fair value	2,162	2,709
One Year or Less, Amortized Cost	0
One Year or Less, Fair Value	0
After One Year through Five Years, Amortized Cost	0
After One Year through Five Years, Fair Value	0
After Five Years through Ten Years, Amortized Cost	0
After Five Years through Ten Years, Fair Value	0
After Ten Years, Amortized Cost	1,335
After Ten Years, Fair Value	2,162
CMBS [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	259	815
Total fair value	259	819
One Year or Less, Amortized Cost	259
One Year or Less, Fair Value	259
After One Year through Five Years, Amortized Cost	0
After One Year through Five Years, Fair Value	0
After Five Years through Ten Years, Amortized Cost	0
After Five Years through Ten Years, Fair Value	0
After Ten Years, Amortized Cost	0
After Ten Years, Fair Value	0
Mortgage revenue bonds [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	858	1,245
Total fair value	873	1,272
One Year or Less, Amortized Cost	10
One Year or Less, Fair Value	10
After One Year through Five Years, Amortized Cost	75
After One Year through Five Years, Fair Value	75
After Five Years through Ten Years, Amortized Cost	112
After Five Years through Ten Years, Fair Value	114
After Ten Years, Amortized Cost	661
After Ten Years, Fair Value	674
Other mortgage-related securities [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	395	431
Total fair value	410	$ 462
One Year or Less, Amortized Cost	0
One Year or Less, Fair Value	0
After One Year through Five Years, Amortized Cost	0
After One Year through Five Years, Fair Value	0
After Five Years through Ten Years, Amortized Cost	3
After Five Years through Ten Years, Fair Value	3
After Ten Years, Amortized Cost	392
After Ten Years, Fair Value	$ 407

Financial Guarantees Financial

Financial Guarantees Financial Guarantees and Maximum Recovery (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Financial Guarantees and Maximum Recovery [Line Items]
Maximum Exposure	$ 26,251	$ 27,942
Guaranty Obligation	264	280
Maximum Recovery	10,135	10,711
Fair value of guaranty obligations in Investments in securities	304	446
Unconsolidated VIEs [Member] | Unconsolidated Fannie Mae MBS [Member]
Financial Guarantees and Maximum Recovery [Line Items]
Maximum Exposure	11,619	12,607
Guaranty Obligation	134	143
Maximum Recovery	7,636	8,048
Unconsolidated VIEs [Member] | Other guaranty arrangements [Member]
Financial Guarantees and Maximum Recovery [Line Items]
Maximum Exposure	14,632	15,335
Guaranty Obligation	130	137
Maximum Recovery	$ 2,499	$ 2,663
Minimum [Member]
Financial Guarantees and Maximum Recovery [Line Items]
Remaining contractual terms of our guarantees	1 day
Maximum [Member]
Financial Guarantees and Maximum Recovery [Line Items]
Remaining contractual terms of our guarantees	35 years

Short-Term Borrowings and Lon68

Short-Term Borrowings and Long-Term Debt Short-Term Borrowings (Details) - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Short-Term Borrowings [Line Items]
Federal funds purchased and securities sold under agreements to repurchase, outstanding	$ 7,000,000	$ 0
Federal funds purchased and securities sold under agreements to repurchase, weighted-average interest rate	0.25%	0.00%
Short-term debt, outstanding	$ 31,012,000,000	$ 35,579,000,000
Short-term debt, weighted-average interest rate	0.84%	0.49%
Secured uncommitted line of credit [Member]
Short-Term Borrowings [Line Items]
Line of credit maximum borrowing capacity	$ 15,000,000,000	$ 15,000,000,000
Line of credit amount outstanding	0
Fannie Mae [Member]
Short-Term Borrowings [Line Items]
Short-term debt, outstanding	$ 30,501,000,000	$ 34,995,000,000
Short-term debt, weighted-average interest rate	0.84%	0.49%
Consolidated Trusts [Member]
Short-Term Borrowings [Line Items]
Short-term debt, outstanding	$ 511,000,000	$ 584,000,000
Short-term debt, weighted-average interest rate	0.91%	0.48%

Short-Term Borrowings and Lon69

Short-Term Borrowings and Long-Term Debt Long-Term Debt (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 3,256,655	$ 3,226,737
Long-term debt, weighted-average interest rate	2.73%	2.54%
Fannie Mae [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 272,619	$ 292,102
Long-term debt, weighted-average interest rate	2.20%	2.31%
Unamortized discounts and premiums, other cost basis adjustments and fair value adjustments	$ 1,000	$ 1,800
Fannie Mae [Member] | Minimum [Member]
Long-Term Debt [Line Items]
Medium-term notes original contractual maturity	1 year	1 year
Long-term debt, original contractual maturity	10 years	10 years
Fannie Mae [Member] | Maximum [Member]
Long-Term Debt [Line Items]
Medium-term notes original contractual maturity	10 years	10 years
Fannie Mae [Member] | Senior Fixed [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 227,650	$ 249,013
Long-term debt, weighted-average interest rate	1.87%	2.14%
Fannie Mae [Member] | Senior fixed benchmark notes and bonds [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 137,509	$ 153,983
Long-term debt, weighted-average interest rate	1.96%	2.16%
Fannie Mae [Member] | Senior fixed medium-term notes [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 82,215	$ 82,230
Long-term debt, weighted-average interest rate	1.42%	1.40%
Fannie Mae [Member] | Senior fixed other debt [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 7,926	$ 12,800
Long-term debt, weighted-average interest rate	4.82%	6.74%
Fannie Mae [Member] | Senior floating [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 40,005	$ 38,333
Long-term debt, weighted-average interest rate	3.14%	2.48%
Fannie Mae [Member] | Senior floating medium-term notes [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 19,051	$ 21,476
Long-term debt, weighted-average interest rate	1.11%	0.71%
Fannie Mae [Member] | Senior floating Connecticut Avenue Securities [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 20,589	$ 16,511
Long-term debt, weighted-average interest rate	5.03%	4.77%
Fannie Mae [Member] | Senior floating other debt [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 365	$ 346
Long-term debt, weighted-average interest rate	7.20%	6.75%
Fannie Mae [Member] | Subordinated debentures [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 4,870	$ 4,645
Long-term debt, weighted-average interest rate	9.93%	9.93%
Fannie Mae [Member] | Secured borrowings [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 94	$ 111
Long-term debt, weighted-average interest rate	1.60%	1.44%
Consolidated Trusts [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 2,984,036	$ 2,934,635
Long-term debt, weighted-average interest rate	2.78%	2.57%

Derivative Instruments Derivati

Derivative Instruments Derivatives 1 - Notional and FV Position (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Asset Derivatives [Abstract]
Notional amount	$ 228,247	$ 156,763
Derivative asset, estimated fair value	419	687
Netting adjustment	(4,024)	(4,514)
Liability Derivatives [Abstract]
Notional amount	319,162	339,456
Derivative liability, estimated fair value	(420)	(1,215)
Netting adjustment	5,034	6,844
Table Footnote [Abstract]
Cash collateral posted for derivative instruments	1,600	2,900
Cash collateral received for derivative instruments	599	535
Risk Management Derivatives [Member]
Asset Derivatives [Abstract]
Notional amount	114,188	86,272
Derivative asset, estimated fair value	3,423	3,785
Accrued interest receivable	707	785
Netting adjustment	(4,024)	(4,514)
Total net risk management derivatives	106	56
Liability Derivatives [Abstract]
Notional amount	226,328	261,475
Derivative liability, estimated fair value	(4,382)	(6,385)
Accrued interest payable	(754)	(937)
Netting adjustment	5,034	6,844
Total net risk management derivatives	(102)	(478)
Mortgage commitment derivatives [Member]
Asset Derivatives [Abstract]
Notional amount	114,059	70,491
Derivative asset, estimated fair value	313	631
Netting adjustment	0	0
Liability Derivatives [Abstract]
Notional amount	92,834	77,981
Derivative liability, estimated fair value	(318)	(737)
Netting adjustment	0	0
Pay-fixed Swap
Asset Derivatives [Abstract]
Notional amount	32,746	29,540
Derivative asset, estimated fair value	441	660
Liability Derivatives [Abstract]
Notional amount	79,878	94,584
Derivative liability, estimated fair value	(2,983)	(4,396)
Receive-fixed Swap
Asset Derivatives [Abstract]
Notional amount	33,890	30,207
Derivative asset, estimated fair value	2,604	2,696
Liability Derivatives [Abstract]
Notional amount	134,172	135,470
Derivative liability, estimated fair value	(1,051)	(1,552)
Basis Swap
Asset Derivatives [Abstract]
Notional amount	12,873	1,624
Derivative asset, estimated fair value	127	115
Liability Derivatives [Abstract]
Notional amount	1,350	15,600
Derivative liability, estimated fair value	(1)	(11)
Foreign Currency Swap
Asset Derivatives [Abstract]
Notional amount	226	214
Derivative asset, estimated fair value	49	40
Liability Derivatives [Abstract]
Notional amount	228	216
Derivative liability, estimated fair value	(72)	(85)
Pay-fixed Swaption
Asset Derivatives [Abstract]
Notional amount	10,250	9,600
Derivative asset, estimated fair value	179	241
Liability Derivatives [Abstract]
Notional amount	2,350	4,850
Derivative liability, estimated fair value	(3)	(82)
Receive-fixed Swaption
Asset Derivatives [Abstract]
Notional amount	0	0
Derivative asset, estimated fair value	0	0
Liability Derivatives [Abstract]
Notional amount	8,350	10,100
Derivative liability, estimated fair value	(271)	(257)
Other
Asset Derivatives [Abstract]
Notional amount	24,203	15,087
Derivative asset, estimated fair value	23	33
Liability Derivatives [Abstract]
Notional amount	0	655
Derivative liability, estimated fair value	(1)	(2)
Mortgage commitments to purchase whole loans
Asset Derivatives [Abstract]
Notional amount	1,898	4,753
Derivative asset, estimated fair value	5	28
Liability Derivatives [Abstract]
Notional amount	6,698	3,039
Derivative liability, estimated fair value	(27)	(49)
Forward contracts to purchase mortgage-related securities
Asset Derivatives [Abstract]
Notional amount	11,791	31,635
Derivative asset, estimated fair value	37	198
Liability Derivatives [Abstract]
Notional amount	69,343	27,297
Derivative liability, estimated fair value	(243)	(388)
Forward contracts to sell mortgage-related securities
Asset Derivatives [Abstract]
Notional amount	100,370	34,103
Derivative asset, estimated fair value	271	405
Liability Derivatives [Abstract]
Notional amount	16,793	47,645
Derivative liability, estimated fair value	$ (48)	$ (300)

Derivative Instruments Deriva71

Derivative Instruments Derivatives 2 - FV Gains and Losses (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	$ (494)	$ (1,557)	$ (462)	$ (4,290)
Net accrual of periodic settlements	5,002	5,286	10,348	10,055
Pay-fixed Swap
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	(691)	(2,257)	0	(7,430)
Receive-fixed Swap
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	639	1,371	322	4,358
Basis Swap
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	16	14	23	49
Foreign Currency Swap
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	11	(34)	23	(31)
Pay-fixed Swaption
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	(48)	4	(48)	29
Receive-fixed Swaption
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	(8)	(19)	(26)	(136)
Other
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	3	22	(5)	160
Risk Management Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	(302)	(1,190)	(190)	(3,561)
Net accrual of periodic settlements	(224)	(291)	(479)	(560)
Mortgage commitment derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	$ (192)	$ (367)	$ (272)	$ (729)

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Net income	$ 3,200	$ 2,946	$ 5,973	$ 4,082
Dividends distributed or available for distribution to senior preferred stockholder	(3,117)	(2,869)	(5,896)	(3,788)
Net income attributable to common stockholders	$ 83	$ 77	$ 77	$ 294
Weighted-average common shares outstanding, Basic	5,762	5,762	5,762	5,762
Convertible preferred stock	131	131	131	131
Weighted-average common shares outstanding, Diluted	5,893	5,893	5,893	5,893
Earnings per share, Basic	$ 0.01	$ 0.01	$ 0.01	$ 0.05
Earnings per share, Diluted	$ 0.01	$ 0.01	$ 0.01	$ 0.05
Weighted average shares of common stock that would be issued upon the full exercise of the warrant issued to Treasury	4,600	4,600	4,600	4,600

Segment Reporting Narrative (De

Segment Reporting Narrative (Details)	6 Months Ended
	Jun. 30, 2017segments
Segment Reporting [Abstract]
Number of Reportable Segments	2

Segment Reporting (Details)

Segment Reporting (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Net interest income	$ 5,002	$ 5,286	$ 10,348	$ 10,055
Fee and other income	353	174	602	377
Net revenues	5,355	5,460	10,950	10,432
Investment gains, net	385	398	376	467
Fair value gains (losses), net	(691)	(1,667)	(731)	(4,480)
Administrative expenses	(686)	(678)	(1,370)	(1,366)
Benefit for credit losses	1,267	1,601	1,663	2,785
Foreclosed property expense	(34)	(63)	(251)	(397)
Total credit-related income	1,233	1,538	1,412	2,388
TCCA fees	(518)	(453)	(1,021)	(893)
Other expenses, net	(291)	(254)	(673)	(518)
Income before federal income taxes	4,787	4,344	8,943	6,030
Provision for federal income taxes	(1,587)	(1,398)	(2,970)	(1,948)
Net income	3,200	2,946	5,973	4,082
US Treasury [Member]
Segment Reporting Information [Line Items]
TCCA fees	(518)	(453)	(1,021)	(893)
Business Segments [Member] | Single-family [Member]
Segment Reporting Information [Line Items]
Net interest income	4,366	4,730	9,122	8,975
Fee and other income	111	78	187	145
Net revenues	4,477	4,808	9,309	9,120
Investment gains, net	321	280	271	336
Fair value gains (losses), net	(685)	(1,679)	(697)	(4,529)
Administrative expenses	(600)	(597)	(1,201)	(1,206)
Benefit for credit losses	1,255	1,596	1,655	2,759
Foreclosed property expense	(32)	(61)	(248)	(396)
Total credit-related income	1,223	1,535	1,407	2,363
Other expenses, net	(155)	(252)	(411)	(498)
Income before federal income taxes	4,063	3,642	7,657	4,693
Provision for federal income taxes	(1,401)	(1,254)	(2,653)	(1,643)
Net income	2,662	2,388	5,004	3,050
Business Segments [Member] | Single-family [Member] | US Treasury [Member]
Segment Reporting Information [Line Items]
TCCA fees	(518)	(453)	(1,021)	(893)
Business Segments [Member] | Multifamily [Member]
Segment Reporting Information [Line Items]
Net interest income	636	556	1,226	1,080
Fee and other income	242	96	415	232
Net revenues	878	652	1,641	1,312
Investment gains, net	64	118	105	131
Fair value gains (losses), net	(6)	12	(34)	49
Administrative expenses	(86)	(81)	(169)	(160)
Benefit for credit losses	12	5	8	26
Foreclosed property expense	(2)	(2)	(3)	(1)
Total credit-related income	10	3	5	25
Other expenses, net	(136)	(2)	(262)	(20)
Income before federal income taxes	724	702	1,286	1,337
Provision for federal income taxes	(186)	(144)	(317)	(305)
Net income	$ 538	$ 558	$ 969	$ 1,032

Equity Activity in OCI (Details

Equity Activity in OCI (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Equity [Abstract]
Net income	$ 3,200	$ 2,946	$ 5,973	$ 4,082
Other comprehensive loss, net of tax effect:
Changes in net unrealized gains (losses) on AFS securities (net of tax of $6 and $27, respectively, for the three months ended and net of tax of $11 and $21, respectively, for the six months ended)	11	50	20	(39)
Reclassification adjustment for OTTI recognized in net income (net of tax of $0 and $1, respectively, for the three months ended and net of tax of $0 and $11, respectively, for the six months ended)	0	1	1	20
Reclassification adjustment for gains on AFS securities included in net income (net of tax of $50 and $68, respectively, for the three months ended and net of tax of $51 and $137, respectively, for the six months ended)	(92)	(126)	(94)	(254)
Other	(2)	(2)	(4)	(4)
Total other comprehensive loss	(83)	(77)	(77)	(277)
Total comprehensive income	3,117	2,869	5,896	3,805
Other Comprehensive Income (Loss), Tax, Parenthetical Disclosures [Abstract]
Changes in net unrealized gains (losses) on AFS securities (net of tax of $6 and $27, respectively, for the three months ended and net of tax of $11 and $21, respectively, for the six months ended)	6	27	11	(21)
Reclassification adjustment for OTTI recognized in net income (net of tax of $0 and $1, respectively, for the three months ended and net of tax of $0 and $11, respectively, for the six months ended)	0	1	0	11
Reclassification adjustment for gains on AFS securities included in net income (net of tax of $50 and $68, respectively, for the three months ended and net of tax of $51 and $137, respectively, for the six months ended)	$ (50)	$ (68)	$ (51)	$ (137)

Equity AOCI (Details)

Equity AOCI (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Equity [Abstract]
Net unrealized gains on AFS securities for which we have not recorded OTTI, net of tax	$ 108	$ 135
Net unrealized gains on AFS securities for which we have recorded OTTI, net of tax	535	581
Other, net of tax	39	43
Accumulated other comprehensive income	$ 682	$ 759

Equity Changes in AOCI (Details

Equity Changes in AOCI (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance			$ 6,071
Net other comprehensive income (loss)	$ (83)	$ (77)	(77)	$ (277)
Ending balance	3,717		3,717
Accumulated net unrealized investment gain (loss), AFS securities [Member]
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	724	1,160	716	1,358
Other comprehensive income (loss) before reclassifications	11	50	20	(39)
Amounts reclassified from other comprehensive income (loss)	(92)	(125)	(93)	(234)
Net other comprehensive income (loss)	(81)	(75)	(73)	(273)
Ending balance	643	1,085	643	1,085
Accumulated other comprehensive income (loss), Other [Member]
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	41	47	43	49
Other comprehensive income (loss) before reclassifications	0	0	0	0
Amounts reclassified from other comprehensive income (loss)	(2)	(2)	(4)	(4)
Net other comprehensive income (loss)	(2)	(2)	(4)	(4)
Ending balance	39	45	39	45
Accumulated other comprehensive income [Member]
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	765	1,207	759	1,407
Other comprehensive income (loss) before reclassifications	11	50	20	(39)
Amounts reclassified from other comprehensive income (loss)	(94)	(127)	(97)	(238)
Net other comprehensive income (loss)	(83)	(77)	(77)	(277)
Ending balance	$ 682	$ 1,130	$ 682	$ 1,130

Concentrations of Credit Risk S

Concentrations of Credit Risk SF Risk Characteristics (Details) - Single-family [Member]	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Guaranty Book of Business [Member] | Conventional Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30 days delinquent (percentage of book of business)	1.14%	1.30%
60 days delinquent (percentage of book of business)	0.30%	0.36%
Seriously delinquent (percentage of book of business)	0.98%	1.18%
30 days delinquent (percentage of conventional loans)	1.32%	1.51%
60 days delinquent (percentage of conventional loans)	0.34%	0.41%
Seriously delinquent (percentage of conventional loans)	1.01%	1.20%
Percentage of loans with detailed loan level information	99.00%	99.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | California
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	0.43%	0.50%
Percentage of book of business	19.00%	19.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | Florida
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	1.51%	1.89%
Percentage of book of business	6.00%	6.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | New Jersey
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	2.49%	3.07%
Percentage of book of business	4.00%	4.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | New York
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	2.21%	2.65%
Percentage of book of business	5.00%	5.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | All other states
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	0.94%	1.11%
Percentage of book of business	66.00%	66.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | Estimated mark-to-market loan-to-value ratio greater than 100%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	10.05%	10.44%
Percentage of book of business	1.00%	2.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | Alt-A [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	4.52%	5.00%
Percentage of book of business	3.00%	3.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | 2004 and prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	2.62%	2.82%
Percentage of book of business	4.00%	5.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | 2005-2008
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	5.73%	6.39%
Percentage of book of business	7.00%	8.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | 2009-2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	0.32%	0.36%
Percentage of book of business	89.00%	87.00%
Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Serious delinquency, days past due	90 days	90 days

Concentrations of Credit Risk M

Concentrations of Credit Risk MF Risk Characteristics (Details) - Multifamily [Member]	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Serious delinquency, days past due	60 days	60 days
Current debt service coverage ratio reporting lag	3 months	3 months
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current debt service coverage ratio (higher risk loans)	1	1
Serious delinquency, days past due	89 days	89 days
Current debt service coverage ratio reporting lag	6 months	6 months
Guaranty Book of Business [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30 days delinquent (percentage of book of business)	0.01%	0.02%
Seriously delinquent (percentage of book of business)	0.04%	0.05%
Percentage of loans with detailed loan level information	99.00%	99.00%
Guaranty Book of Business [Member] | Original LTV ratio greater than 80% [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	2.00%	2.00%
Loans seriously delinquent, percentage by unpaid principal balance	0.17%	0.22%
Guaranty Book of Business [Member] | Original LTV ratio less than or equal to 80% [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	98.00%	98.00%
Loans seriously delinquent, percentage by unpaid principal balance	0.04%	0.05%
Guaranty Book of Business [Member] | Current DSCR less than 100% [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	1.00%	2.00%
Loans seriously delinquent, percentage by unpaid principal balance	2.12%	1.96%

Concentrations of Credit Risk O

Concentrations of Credit Risk Other Concentrations (Details) $ in Millions	Jun. 30, 2017USD ($)servicersinsurers	Dec. 31, 2016USD ($)servicersinsurers
Concentration Risk [Line Items]
Estimated benefit included in total loss reserves	$ 1,100	$ 1,400
Receivable from claims on insured, defaulted loans excluding government insured loans	926	1,000
Allowance for mortgage insurance receivable	612	638
Mortgage Sellers and Servicers [Member]
Concentration Risk [Line Items]
Receivable from claims on insured, defaulted loans excluding government insured loans	$ 106	$ 141
Single-family [Member]
Concentration Risk [Line Items]
Number of mortgage servicers, including their affiliates, which serviced the majority of our guaranty book of business | servicers	5	5
Number of mortgage insurance companies provided majority of our mortgage insurance | insurers	3	3
Number of mortgage Insurers publicly disclosed credit quality deterioration | insurers	3
Single-family [Member] | Guaranty Book of Business [Member]
Concentration Risk [Line Items]
Mortgage insurance coverage risk in force	$ 131,500	$ 126,200
Mortgage insurance coverage risk in force as percentage	5.00%	4.00%
Primary mortgage insurance coverage risk in force	$ 130,900	$ 125,600
Pool mortgage insurance coverage risk in force	$ 565	$ 617
Single-family [Member] | Guaranty Book of Business [Member] | Credit Concentration Risk [Member] | Group of Largest Mortgage Servicers including Affiliates [Member]
Concentration Risk [Line Items]
Percentage of concentration risk	40.00%	39.00%
Single-family [Member] | Guaranty Book of Business [Member] | Insurance Service Provider Concentration Risk [Member]
Concentration Risk [Line Items]
Percentage of concentration risk	5.00%
Mortgage insurance coverage risk in force for insurers with credit quality deterioration	$ 7,100
Single-family [Member] | Guaranty Book of Business [Member] | Insurance Service Provider Concentration Risk [Member] | Group of Top Mortgage Insurance Companies [Member]
Concentration Risk [Line Items]
Percentage of concentration risk	66.00%	66.00%
Multifamily [Member]
Concentration Risk [Line Items]
Number of mortgage servicers, including their affiliates, which serviced the majority of our guaranty book of business | servicers	5	5
Multifamily [Member] | Guaranty Book of Business [Member] | Credit Concentration Risk [Member] | Group of Largest Mortgage Servicers including Affiliates [Member]
Concentration Risk [Line Items]
Percentage of concentration risk	47.00%	47.00%

Netting Arrangements (Details)

Netting Arrangements (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Assets:
Derivative assets, gross amount	$ 4,420	$ 5,168
Derivative assets, gross amount offset	(4,024)	(4,514)
Derivative assets, net amount presented in our condensed consolidated balance sheets	396	654
Derivative assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	(234)	(357)
Derivative assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	0	(22)
Derivative assets, net amount	162	275
Securities purchased under agreements to resell or similar arrangements, gross amount	41,120	51,115
Securities purchased under agreements to resell or similar arrangements, gross amount offset	0	0
Securities purchased under agreements to resell or similar arrangements, net amount presented in our condensed consolidated balance sheets	41,120	51,115
Securities purchased under agreements to resell or similar arrangements, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	0	0
Securities purchased under agreements to resell or similar arrangements, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	(41,120)	(51,115)
Securities purchased under agreements to resell or similar arrangements, net amount	0	0
Total assets, gross amount	45,540	56,283
Total assets, gross amount offset	(4,024)	(4,514)
Total assets, net amount presented in our condensed consolidated balance sheets	41,516	51,769
Total assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	(234)	(357)
Total assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	(41,120)	(51,137)
Total assets, net amount	162	275
Liabilities:
Derivative liabilities, gross amount	(5,453)	(8,057)
Derivative liabilities, gross amount offset	5,034	6,844
Derivative liabilities, net amount presented in our condensed consolidated balance sheets	(419)	(1,213)
Derivative liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	234	357
Derivative liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	2	107
Derivative liabilities, net amount	(183)	(749)
Securities sold under agreements to repurchase or similar arrangements, gross amount	(7)
Securities sold under agreements to repurchase or similar arrangements, gross amount offset	0
Securities sold under agreements to repurchase or similar arrangements, net amount presented in our condensed consolidated balance sheets	(7)
Securities sold under agreements to repurchase or similar arrangements, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	0
Securities sold under agreements to repurchase or similar arrangements, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	7
Securities sold under agreements to repurchase or similar arrangements, net amount	0
Total liabilities, gross amount	(5,460)	(8,057)
Total liabilities, gross amount offset	5,034	6,844
Total liabilities, net amount presented in our condensed consolidated balance sheets	(426)	(1,213)
Total liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	234	357
Total liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	9	107
Total liabilities, net amount	(183)	(749)
Risk Management Derivatives [Member]
Assets:
Derivative assets, gross amount offset	(4,024)	(4,514)
Liabilities:
Derivative liabilities, gross amount offset	5,034	6,844
Mortgage commitment derivatives [Member]
Assets:
Derivative assets, gross amount	313	631
Derivative assets, gross amount offset	0	0
Derivative assets, net amount presented in our condensed consolidated balance sheets	313	631
Derivative assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	(234)	(357)
Derivative assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	0	(22)
Derivative assets, net amount	79	252
Liabilities:
Derivative liabilities, gross amount	(318)	(737)
Derivative liabilities, gross amount offset	0	0
Derivative liabilities, net amount presented in our condensed consolidated balance sheets	(318)	(737)
Derivative liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	234	357
Derivative liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	0	16
Derivative liabilities, net amount	(84)	(364)
Over the Counter [Member] | Risk Management Derivatives [Member]
Assets:
Derivative assets, gross amount	2,800	3,688
Derivative assets, gross amount offset	(2,753)	(3,667)
Derivative assets, net amount presented in our condensed consolidated balance sheets	47	21
Derivative assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	0	0
Derivative assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	0	0
Derivative assets, net amount	47	21
Liabilities:
Derivative liabilities, gross amount	(3,564)	(4,905)
Derivative liabilities, gross amount offset	3,465	4,520
Derivative liabilities, net amount presented in our condensed consolidated balance sheets	(99)	(385)
Derivative liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	0	0
Derivative liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	0	0
Derivative liabilities, net amount	(99)	(385)
Exchange Cleared [Member] | Risk Management Derivatives [Member]
Assets:
Derivative assets, gross amount	1,307	849
Derivative assets, gross amount offset	(1,271)	(847)
Derivative assets, net amount presented in our condensed consolidated balance sheets	36	2
Derivative assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	0	0
Derivative assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	0	0
Derivative assets, net amount	36	2
Liabilities:
Derivative liabilities, gross amount	(1,571)	(2,415)
Derivative liabilities, gross amount offset	1,569	2,324
Derivative liabilities, net amount presented in our condensed consolidated balance sheets	(2)	(91)
Derivative liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	0	0
Derivative liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	2	91
Derivative liabilities, net amount	$ 0	$ 0

Netting Arrangements Narratives

Netting Arrangements Narratives (Details) - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Fair value of non-cash collateral we pledged	$ 1,000,000,000	$ 1,300,000,000
Fair value of non-cash collateral received	41,200,000,000	51,200,000,000
Fair value of non-cash collateral received that can be resold or repledged	38,900,000,000	45,500,000,000
Fair value of securities received as collateral that have been resold or repledge	0	0
Derivative assets not subject to enforceable master netting arrangements	23,000,000	33,000,000
Derivative liabilities not subject to enforceable master netting arrangements	1,000,000	2,000,000
Cash and Cash Equivalents [Member]
Derivative [Line Items]
Securities purchased under agreements to resell	$ 11,900,000,000	$ 20,700,000,000

Fair Value Levels Hierarchy (De

Fair Value Levels Hierarchy (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Assets [Abstract]
Mortgage loans held for investment, at fair value	$ 11,406	$ 12,057
Other assets [Abstract]
Derivative assets, gross amount offset	(4,024)	(4,514)
Other liabilities [Abstract]
Derivative liabilities, gross amount offset	(5,034)	(6,844)
Mortgage commitment derivatives [Member]
Other assets [Abstract]
Derivative assets, gross amount offset	0	0
Other liabilities [Abstract]
Derivative liabilities, gross amount offset	0	0
Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	9,008	9,582
Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	34,866	36,524
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets [Abstract]
Trading securities	32,418	32,317
Available-for-sale securities	0	0
Mortgage loans held for investment, at fair value	0	0
Other assets [Abstract]
Derivatives assets at fair value	0	0
Total assets at fair value	68,421	73,794
Other liabilities [Abstract]
Derivative liabilities at fair value	0	0
Total liabilities at fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	0	0
Significant Other Observable Inputs (Level 2) [Member]
Assets [Abstract]
Trading securities	4,720	7,118
Available-for-sale securities	4,771	6,210
Mortgage loans held for investment, at fair value	2,828,761	2,767,813
Other assets [Abstract]
Derivatives assets at fair value	4,276	5,019
Total assets at fair value	2,891,500	2,844,940
Other liabilities [Abstract]
Derivative liabilities at fair value	5,411	7,921
Total liabilities at fair value	3,271,106	3,243,215
Significant Other Observable Inputs (Level 2) [Member] | Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	280,471	298,980
Significant Other Observable Inputs (Level 2) [Member] | Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	2,954,716	2,901,316
Significant Unobservable Inputs (Level 3) [Member]
Assets [Abstract]
Trading securities	2,136	1,127
Available-for-sale securities	1,637	2,153
Mortgage loans held for investment, at fair value	322,070	316,742
Other assets [Abstract]
Derivatives assets at fair value	167	182
Total assets at fair value	329,662	323,739
Other liabilities [Abstract]
Derivative liabilities at fair value	43	138
Total liabilities at fair value	42,402	38,870
Significant Unobservable Inputs (Level 3) [Member] | Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	812	770
Significant Unobservable Inputs (Level 3) [Member] | Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	40,513	36,668
Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading securities	39,274	40,562
Available-for-sale securities	6,408	8,363
Mortgage loans held for investment, at fair value	11,406	12,057
Other assets [Abstract]
Derivatives assets at fair value	419	687
Derivative assets, gross amount offset	(4,024)	(4,514)
Total assets at fair value	57,507	61,669
Liabilities [Abstract]
Long-term debt, fair value	43,874	46,106
Other liabilities [Abstract]
Derivative liabilities at fair value	420	1,215
Derivative liabilities, gross amount offset	(5,034)	(6,844)
Total liabilities at fair value	44,294	47,321
Recurring Fair Value Measurements [Member] | Swaps [Member]
Other assets [Abstract]
Derivatives assets at fair value	3,928	4,296
Other liabilities [Abstract]
Derivative liabilities at fair value	4,861	6,981
Recurring Fair Value Measurements [Member] | Swaptions [Member]
Other assets [Abstract]
Derivatives assets at fair value	179	241
Other liabilities [Abstract]
Derivative liabilities at fair value	274	339
Recurring Fair Value Measurements [Member] | Other [Member]
Other assets [Abstract]
Derivatives assets at fair value	23	33
Other liabilities [Abstract]
Derivative liabilities at fair value	1	2
Recurring Fair Value Measurements [Member] | Mortgage commitment derivatives [Member]
Other assets [Abstract]
Derivatives assets at fair value	313	631
Other liabilities [Abstract]
Derivative liabilities at fair value	318	737
Recurring Fair Value Measurements [Member] | Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	9,008	9,582
Recurring Fair Value Measurements [Member] | Fannie Mae [Member] | Senior floating [Member]
Liabilities [Abstract]
Long-term debt, fair value	9,008	9,582
Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	34,866	36,524
Recurring Fair Value Measurements [Member] | Fannie Mae [Member]
Assets [Abstract]
Trading securities	4,277	4,769
Available-for-sale securities	2,272	2,554
Recurring Fair Value Measurements [Member] | Other agency [Member]
Assets [Abstract]
Trading securities	1,969	2,058
Available-for-sale securities	432	547
Recurring Fair Value Measurements [Member] | Alt-A and subprime private-label securities [Member]
Assets [Abstract]
Trading securities	593	636
Available-for-sale securities	2,162	2,709
Recurring Fair Value Measurements [Member] | CMBS [Member]
Assets [Abstract]
Trading securities	16	761
Available-for-sale securities	259	819
Recurring Fair Value Measurements [Member] | Mortgage revenue bonds [Member]
Assets [Abstract]
Trading securities	1	21
Available-for-sale securities	873	1,272
Recurring Fair Value Measurements [Member] | Other [Member]
Assets [Abstract]
Available-for-sale securities	410	462
Recurring Fair Value Measurements [Member] | U.S. Treasury securities [Member]
Assets [Abstract]
Trading securities	32,418	32,317
Recurring Fair Value Measurements [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets [Abstract]
Trading securities	32,418	32,317
Available-for-sale securities	0	0
Mortgage loans held for investment, at fair value	0	0
Other assets [Abstract]
Derivatives assets at fair value	0	0
Total assets at fair value	32,418	32,317
Liabilities [Abstract]
Long-term debt, fair value	0	0
Other liabilities [Abstract]
Derivative liabilities at fair value	0	0
Total liabilities at fair value	0	0
Recurring Fair Value Measurements [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Swaps [Member]
Other assets [Abstract]
Derivatives assets at fair value	0	0
Other liabilities [Abstract]
Derivative liabilities at fair value	0	0
Recurring Fair Value Measurements [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Swaptions [Member]
Other assets [Abstract]
Derivatives assets at fair value	0	0
Other liabilities [Abstract]
Derivative liabilities at fair value	0	0
Recurring Fair Value Measurements [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other [Member]
Other assets [Abstract]
Derivatives assets at fair value	0	0
Other liabilities [Abstract]
Derivative liabilities at fair value	0	0
Recurring Fair Value Measurements [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mortgage commitment derivatives [Member]
Other assets [Abstract]
Derivatives assets at fair value	0	0
Other liabilities [Abstract]
Derivative liabilities at fair value	0	0
Recurring Fair Value Measurements [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	0	0
Recurring Fair Value Measurements [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fannie Mae [Member] | Senior floating [Member]
Liabilities [Abstract]
Long-term debt, fair value	0	0
Recurring Fair Value Measurements [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	0	0
Recurring Fair Value Measurements [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fannie Mae [Member]
Assets [Abstract]
Trading securities	0	0
Available-for-sale securities	0	0
Recurring Fair Value Measurements [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other agency [Member]
Assets [Abstract]
Trading securities	0	0
Available-for-sale securities	0	0
Recurring Fair Value Measurements [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Alt-A and subprime private-label securities [Member]
Assets [Abstract]
Trading securities	0	0
Available-for-sale securities	0	0
Recurring Fair Value Measurements [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | CMBS [Member]
Assets [Abstract]
Trading securities	0	0
Available-for-sale securities	0	0
Recurring Fair Value Measurements [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mortgage revenue bonds [Member]
Assets [Abstract]
Trading securities	0	0
Available-for-sale securities	0	0
Recurring Fair Value Measurements [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other [Member]
Assets [Abstract]
Available-for-sale securities	0	0
Recurring Fair Value Measurements [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | U.S. Treasury securities [Member]
Assets [Abstract]
Trading securities	32,418	32,317
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets [Abstract]
Trading securities	4,720	7,118
Available-for-sale securities	4,771	6,210
Mortgage loans held for investment, at fair value	10,287	10,860
Other assets [Abstract]
Derivatives assets at fair value	4,276	5,019
Total assets at fair value	24,054	29,207
Liabilities [Abstract]
Long-term debt, fair value	42,749	45,518
Other liabilities [Abstract]
Derivative liabilities at fair value	5,411	7,921
Total liabilities at fair value	48,160	53,439
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Swaps [Member]
Other assets [Abstract]
Derivatives assets at fair value	3,784	4,159
Other liabilities [Abstract]
Derivative liabilities at fair value	4,837	6,933
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Swaptions [Member]
Other assets [Abstract]
Derivatives assets at fair value	179	241
Other liabilities [Abstract]
Derivative liabilities at fair value	274	339
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Other [Member]
Other assets [Abstract]
Derivatives assets at fair value	0	0
Other liabilities [Abstract]
Derivative liabilities at fair value	0	0
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Mortgage commitment derivatives [Member]
Other assets [Abstract]
Derivatives assets at fair value	313	619
Other liabilities [Abstract]
Derivative liabilities at fair value	300	649
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	8,643	9,235
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fannie Mae [Member] | Senior floating [Member]
Liabilities [Abstract]
Long-term debt, fair value	8,643	9,235
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	34,106	36,283
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fannie Mae [Member]
Assets [Abstract]
Trading securities	2,406	3,934
Available-for-sale securities	2,066	2,324
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Other agency [Member]
Assets [Abstract]
Trading securities	1,969	2,058
Available-for-sale securities	432	542
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Alt-A and subprime private-label securities [Member]
Assets [Abstract]
Trading securities	329	365
Available-for-sale securities	1,984	2,492
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | CMBS [Member]
Assets [Abstract]
Trading securities	16	761
Available-for-sale securities	259	819
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Mortgage revenue bonds [Member]
Assets [Abstract]
Trading securities	0	0
Available-for-sale securities	0	0
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Other [Member]
Assets [Abstract]
Available-for-sale securities	30	33
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. Treasury securities [Member]
Assets [Abstract]
Trading securities	0	0
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets [Abstract]
Trading securities	2,136	1,127
Available-for-sale securities	1,637	2,153
Mortgage loans held for investment, at fair value	1,119	1,197
Other assets [Abstract]
Derivatives assets at fair value	167	182
Total assets at fair value	5,059	4,659
Liabilities [Abstract]
Long-term debt, fair value	1,125	588
Other liabilities [Abstract]
Derivative liabilities at fair value	43	138
Total liabilities at fair value	1,168	726
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Swaps [Member]
Other assets [Abstract]
Derivatives assets at fair value	144	137
Other liabilities [Abstract]
Derivative liabilities at fair value	24	48
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Swaptions [Member]
Other assets [Abstract]
Derivatives assets at fair value	0	0
Other liabilities [Abstract]
Derivative liabilities at fair value	0	0
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other [Member]
Other assets [Abstract]
Derivatives assets at fair value	23	33
Other liabilities [Abstract]
Derivative liabilities at fair value	1	2
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Mortgage commitment derivatives [Member]
Other assets [Abstract]
Derivatives assets at fair value	0	12
Other liabilities [Abstract]
Derivative liabilities at fair value	18	88
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	365	347
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fannie Mae [Member] | Senior floating [Member]
Liabilities [Abstract]
Long-term debt, fair value	365	347
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	760	241
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fannie Mae [Member]
Assets [Abstract]
Trading securities	1,871	835
Available-for-sale securities	206	230
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other agency [Member]
Assets [Abstract]
Trading securities	0	0
Available-for-sale securities	0	5
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Alt-A and subprime private-label securities [Member]
Assets [Abstract]
Trading securities	264	271
Available-for-sale securities	178	217
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | CMBS [Member]
Assets [Abstract]
Trading securities	0	0
Available-for-sale securities	0	0
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Mortgage revenue bonds [Member]
Assets [Abstract]
Trading securities	1	21
Available-for-sale securities	873	1,272
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other [Member]
Assets [Abstract]
Available-for-sale securities	380	429
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. Treasury securities [Member]
Assets [Abstract]
Trading securities	$ 0	$ 0

Fair Value Level 3 Rollforward

Fair Value Level 3 Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Trading securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	$ 2	$ 33	$ 13	$ (30)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,148	677	1,127	1,398
Total gains (losses) (realized/unrealized) Included in Net Income	7	44	18	(35)
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases	63	0	63	0
Sales	(21)	(184)	(21)	(466)
Issues	0	0	0	0
Settlements	(14)	(16)	(25)	(39)
Transfers out of Level 3	(21)	(25)	(22)	(388)
Transfers into Level 3	974	0	996	26
Ending Balance	2,136	496	2,136	496
Trading securities [Member] | Fannie Mae [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0	2	0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	856	25	835	0
Total gains (losses) (realized/unrealized) Included in Net Income	1	0	4	0
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases	63	0	63	0
Sales	0	0	0	0
Issues	0	0	0	0
Settlements	(2)	(1)	(5)	(1)
Transfers out of Level 3	(21)	(24)	(22)	(24)
Transfers into Level 3	974	0	996	25
Ending Balance	1,871	0	1,871	0
Trading securities [Member] | Other agency [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance		1		0
Total gains (losses) (realized/unrealized) Included in Net Income		0		0
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)		0		0
Purchases		0		0
Sales		0		0
Issues		0		0
Settlements		0		0
Transfers out of Level 3		(1)		(1)
Transfers into Level 3		0		1
Ending Balance		0		0
Trading securities [Member] | Alt-A and subprime private-label securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	2	27	11	(40)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	272	288	271	949
Total gains (losses) (realized/unrealized) Included in Net Income	3	27	11	(64)
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	(187)
Issues	0	0	0	0
Settlements	(11)	(12)	(18)	(32)
Transfers out of Level 3	0	0	0	(363)
Transfers into Level 3	0	0	0	0
Ending Balance	264	303	264	303
Trading securities [Member] | Mortgage revenue bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	6	0	10
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	20	363	21	449
Total gains (losses) (realized/unrealized) Included in Net Income	3	17	3	29
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases	0	0	0	0
Sales	(21)	(184)	(21)	(279)
Issues	0	0	0	0
Settlements	(1)	(3)	(2)	(6)
Transfers out of Level 3	0	0	0	0
Transfers into Level 3	0	0	0	0
Ending Balance	1	193	1	193
Available-for-sale securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0	0	0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	2,039	3,621	2,153	8,431
Total gains (losses) (realized/unrealized) Included in Net Income	34	80	36	184
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	(54)	26	(43)	(137)
Purchases	0	0	0	0
Sales	(312)	(769)	(325)	(2,091)
Issues	0	0	0	0
Settlements	(49)	(128)	(163)	(433)
Transfers out of Level 3	(21)	(2)	(51)	(3,127)
Transfers into Level 3	0	0	30	1
Ending Balance	1,637	2,828	1,637	2,828
Available-for-sale securities [Member] | Fannie Mae [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0	0	0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	232	1	230	0
Total gains (losses) (realized/unrealized) Included in Net Income	0	0	1	0
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	(3)	0	(2)	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issues	0	0	0	0
Settlements	(2)	0	(6)	0
Transfers out of Level 3	(21)	(1)	(47)	(1)
Transfers into Level 3	0	0	30	1
Ending Balance	206	0	206	0
Available-for-sale securities [Member] | Other agency [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0	0	0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance		2	5	4
Total gains (losses) (realized/unrealized) Included in Net Income		0	0	0
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)		0	0	0
Purchases		0	0	0
Sales		0	(1)	0
Issues		0	0	0
Settlements		0	0	0
Transfers out of Level 3		(1)	(4)	(3)
Transfers into Level 3		0	0	0
Ending Balance	0	1	0	1
Available-for-sale securities [Member] | Alt-A and subprime private-label securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0	0	0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	205	399	217	4,322
Total gains (losses) (realized/unrealized) Included in Net Income	0	1	0	104
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	(21)	9	(15)	(159)
Purchases	0	0	0	0
Sales	0	0	0	(875)
Issues	0	0	0	0
Settlements	(6)	(61)	(24)	(205)
Transfers out of Level 3	0	0	0	(2,839)
Transfers into Level 3	0	0	0	0
Ending Balance	178	348	178	348
Available-for-sale securities [Member] | Mortgage revenue bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0	0	0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,185	2,564	1,272	2,701
Total gains (losses) (realized/unrealized) Included in Net Income	34	76	35	80
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	(11)	18	(12)	48
Purchases	0	0	0	0
Sales	(312)	(568)	(324)	(611)
Issues	0	0	0	0
Settlements	(23)	(61)	(98)	(189)
Transfers out of Level 3	0	0	0	0
Transfers into Level 3	0	0	0	0
Ending Balance	873	2,029	873	2,029
Available-for-sale securities [Member] | Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0	0	0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	417	655	429	1,404
Total gains (losses) (realized/unrealized) Included in Net Income	0	3	0	0
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	(19)	(1)	(14)	(26)
Purchases	0	0	0	0
Sales	0	(201)	0	(605)
Issues	0	0	0	0
Settlements	(18)	(6)	(35)	(39)
Transfers out of Level 3	0	0	0	(284)
Transfers into Level 3	0	0	0	0
Ending Balance	380	450	380	450
Mortgage loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	19	10	16	20
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,149	1,311	1,197	1,477
Total gains (losses) (realized/unrealized) Included in Net Income	24	15	32	116
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases	0	25	0	25
Sales	0	0	0	(320)
Issues	0	0	0	0
Settlements	(55)	(67)	(117)	(139)
Transfers out of Level 3	(21)	(19)	(67)	(84)
Transfers into Level 3	22	15	74	205
Ending Balance	1,119	1,280	1,119	1,280
Net derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	9	41	0	76
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	113	231	44	157
Total gains (losses) (realized/unrealized) Included in Net Income	27	52	100	232
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issues	0	(3)	0	(7)
Settlements	(16)	(33)	(24)	(133)
Transfers out of Level 3	0	0	5	(2)
Transfers into Level 3	0	1	(1)	1
Ending Balance	124	248	124	248
Long-term debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	(19)	(22)	(22)	(49)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(564)	(641)	(588)	(865)
Total gains (losses) (realized/unrealized) Included in Net Income	(20)	(22)	(22)	(116)
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issues	0	(47)	(2)	(54)
Settlements	12	9	19	318
Transfers out of Level 3	22	8	88	45
Transfers into Level 3	(575)	(43)	(620)	(64)
Ending Balance	(1,125)	(736)	(1,125)	(736)
Long-term debt [Member] | Consolidated Trusts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	(5)	(7)	(4)	(8)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(214)	(246)	(241)	(496)
Total gains (losses) (realized/unrealized) Included in Net Income	(5)	(7)	(4)	(75)
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issues	0	(47)	(2)	(54)
Settlements	12	9	19	318
Transfers out of Level 3	22	8	88	45
Transfers into Level 3	(575)	(43)	(620)	(64)
Ending Balance	(760)	(326)	(760)	(326)
Long-term debt [Member] | Senior floating [Member] | Fannie Mae [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	(14)	(15)	(18)	(41)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(350)	(395)	(347)	(369)
Total gains (losses) (realized/unrealized) Included in Net Income	(15)	(15)	(18)	(41)
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issues	0	0	0	0
Settlements	0	0	0	0
Transfers out of Level 3	0	0	0	0
Transfers into Level 3	0	0	0	0
Ending Balance	$ (365)	$ (410)	$ (365)	$ (410)

Fair Value Level 3 Valuation In

Fair Value Level 3 Valuation Inputs (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	$ 11,406	$ 12,057
Derivatives	396	654
Fannie Mae [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(9,008)	(9,582)
Consolidated Trusts [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(34,866)	(36,524)
Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	39,274	40,562
Available-for-sale securities	6,408	8,363
Mortgage loans held for investment, at fair value	11,406	12,057
Long-term Debt, Fair Value	(43,874)	(46,106)
Recurring Fair Value Measurements [Member] | Alt-A and subprime private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	593	636
Available-for-sale securities	2,162	2,709
Recurring Fair Value Measurements [Member] | Mortgage revenue bonds [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	1	21
Available-for-sale securities	873	1,272
Recurring Fair Value Measurements [Member] | Other [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	410	462
Recurring Fair Value Measurements [Member] | Fannie Mae [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(9,008)	(9,582)
Recurring Fair Value Measurements [Member] | Fannie Mae [Member] | Senior floating [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(9,008)	(9,582)
Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(34,866)	(36,524)
Significant Other Observable Inputs (Level 2) [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	3,193	509
Trading securities	4,720	7,118
Available-for-sale securities	4,771	6,210
Mortgage loans held for investment, at fair value	2,828,761	2,767,813
Significant Other Observable Inputs (Level 2) [Member] | Fannie Mae [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(280,471)	(298,980)
Significant Other Observable Inputs (Level 2) [Member] | Consolidated Trusts [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(2,954,716)	(2,901,316)
Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	4,720	7,118
Available-for-sale securities	4,771	6,210
Mortgage loans held for investment, at fair value	10,287	10,860
Long-term Debt, Fair Value	(42,749)	(45,518)
Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member] | Alt-A and subprime private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	329	365
Available-for-sale securities	1,984	2,492
Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member] | Mortgage revenue bonds [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	0	0
Available-for-sale securities	0	0
Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member] | Other [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	30	33
Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member] | Fannie Mae [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(8,643)	(9,235)
Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member] | Fannie Mae [Member] | Senior floating [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(8,643)	(9,235)
Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(34,106)	(36,283)
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	814	250
Significant Unobservable Inputs (Level 3) [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	2,897	2,751
Trading securities	2,136	1,127
Available-for-sale securities	1,637	2,153
Mortgage loans held for investment, at fair value	322,070	316,742
Significant Unobservable Inputs (Level 3) [Member] | Fannie Mae [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(812)	(770)
Significant Unobservable Inputs (Level 3) [Member] | Consolidated Trusts [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(40,513)	(36,668)
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	2,136	1,127
Available-for-sale securities	1,637	2,153
Mortgage loans held for investment, at fair value	1,119	1,197
Derivatives	124	44
Long-term Debt, Fair Value	(1,125)	(588)
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Agency [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	1,871	835
Available-for-sale securities		235
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Alt-A and subprime private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	264	271
Available-for-sale securities	178	217
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Mortgage revenue bonds [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	1	21
Available-for-sale securities	873	1,272
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Other [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	380	429
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor With Inputs [Member] | Agency [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	$ 1,815
Available-for-sale securities		$ 129
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor With Inputs [Member] | Agency [Member] | Trading securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Prepayment Speed (%)	0.00%
Spreads (%)	0.327%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor With Inputs [Member] | Agency [Member] | Trading securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Prepayment Speed (%)	177.00%
Spreads (%)	2.10%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor With Inputs [Member] | Agency [Member] | Trading securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Prepayment Speed (%)	170.40%
Spreads (%)	1.86%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor With Inputs [Member] | Agency [Member] | Available-for-sale securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Prepayment Speed (%)		124.80%
Spreads (%)		1.75%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor With Inputs [Member] | Agency [Member] | Available-for-sale securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Prepayment Speed (%)		165.50%
Spreads (%)		2.10%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor With Inputs [Member] | Agency [Member] | Available-for-sale securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Prepayment Speed (%)		142.40%
Spreads (%)		1.825%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor With Inputs [Member] | Alt-A and subprime private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities		$ 93
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor With Inputs [Member] | Alt-A and subprime private-label securities [Member] | Available-for-sale securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		2.50%
Prepayment Speed (%)		3.00%
Severity (%)		38.00%
Spreads (%)		2.661%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor With Inputs [Member] | Alt-A and subprime private-label securities [Member] | Available-for-sale securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		8.00%
Prepayment Speed (%)		11.00%
Severity (%)		80.00%
Spreads (%)		3.068%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor With Inputs [Member] | Alt-A and subprime private-label securities [Member] | Available-for-sale securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		3.80%
Prepayment Speed (%)		4.90%
Severity (%)		48.10%
Spreads (%)		2.971%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor With Inputs [Member] | Mortgage revenue bonds [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	$ 656	$ 684
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor With Inputs [Member] | Mortgage revenue bonds [Member] | Available-for-sale securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)	0.045%	(0.168%)
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor With Inputs [Member] | Mortgage revenue bonds [Member] | Available-for-sale securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)	3.668%	3.369%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor With Inputs [Member] | Mortgage revenue bonds [Member] | Available-for-sale securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)	0.581%	0.443%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor Without Inputs [Member] | Mortgage revenue bonds [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities		$ 126
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Derivatives	$ 3	(76)
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Various Valuation Technique without Inputs [Member] | Agency [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	56	26
Available-for-sale securities	206	34
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Various Valuation Technique without Inputs [Member] | Alt-A and subprime private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	178	79
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Various Valuation Technique without Inputs [Member] | Mortgage revenue bonds [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	1	2
Available-for-sale securities	72	27
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Various Valuation Technique without Inputs [Member] | Other [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	71	34
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus Without Inputs [Member] | Agency [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities		809
Available-for-sale securities		72
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus Without Inputs [Member] | Alt-A and subprime private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	264	39
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Alt-A and subprime private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities		$ 232
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Alt-A and subprime private-label securities [Member] | Trading securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		0.40%
Prepayment Speed (%)		4.30%
Severity (%)		71.00%
Spreads (%)		2.446%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Alt-A and subprime private-label securities [Member] | Trading securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		10.90%
Prepayment Speed (%)		7.40%
Severity (%)		95.00%
Spreads (%)		2.539%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Alt-A and subprime private-label securities [Member] | Trading securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		8.20%
Prepayment Speed (%)		6.60%
Severity (%)		88.90%
Spreads (%)		2.515%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Other [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities		$ 47
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Other [Member] | Available-for-sale securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		0.50%
Prepayment Speed (%)		2.50%
Severity (%)		20.00%
Spreads (%)		2.216%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Other [Member] | Available-for-sale securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		3.50%
Prepayment Speed (%)		6.00%
Severity (%)		88.00%
Spreads (%)		3.002%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Other [Member] | Available-for-sale securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		3.50%
Prepayment Speed (%)		2.50%
Severity (%)		87.50%
Spreads (%)		2.377%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Alt-A and subprime private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities		$ 45
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Alt-A and subprime private-label securities [Member] | Available-for-sale securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)		3.61%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Alt-A and subprime private-label securities [Member] | Available-for-sale securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)		4.50%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Alt-A and subprime private-label securities [Member] | Available-for-sale securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)		4.06%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Mortgage revenue bonds [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities		$ 19
Available-for-sale securities	$ 145	$ 435
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Mortgage revenue bonds [Member] | Trading securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)		0.13%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Mortgage revenue bonds [Member] | Trading securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)		2.682%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Mortgage revenue bonds [Member] | Trading securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)		2.522%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Mortgage revenue bonds [Member] | Available-for-sale securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)	0.045%	(0.168%)
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Mortgage revenue bonds [Member] | Available-for-sale securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)	4.133%	3.911%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Mortgage revenue bonds [Member] | Available-for-sale securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)	1.936%	2.60%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Other [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	$ 309	$ 348
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Other [Member] | Available-for-sale securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	1.20%	2.30%
Prepayment Speed (%)	0.50%	0.50%
Severity (%)	95.00%	95.00%
Spreads (%)	1.02%	1.90%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Other [Member] | Available-for-sale securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	1.20%	2.30%
Prepayment Speed (%)	0.50%	0.50%
Severity (%)	95.00%	95.00%
Spreads (%)	6.10%	4.50%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Other [Member] | Available-for-sale securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	1.20%	2.30%
Prepayment Speed (%)	0.50%	0.50%
Severity (%)	95.00%	95.00%
Spreads (%)	6.044%	4.491%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Derivatives		$ 21
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Dealer Mark [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Derivatives	$ 121	89
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Internal Model [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Derivatives		10
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-family [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	958	1,034
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-family [Member] | Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	51	218
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-family [Member] | Consensus Without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	398	300
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-family [Member] | Build-Up without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	509	516
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Multifamily [Member] | Build-Up with inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	$ 161	$ 163
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Multifamily [Member] | Build-Up with inputs [Member] | Mortgage loans [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)	0.47%	0.55%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Multifamily [Member] | Build-Up with inputs [Member] | Mortgage loans [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)	2.932%	3.052%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Multifamily [Member] | Build-Up with inputs [Member] | Mortgage loans [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)	1.291%	1.402%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Fannie Mae [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	$ (365)	$ (347)
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Fannie Mae [Member] | Senior floating [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(365)	(347)
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Fannie Mae [Member] | Discounted Cash Flow without Inputs [Member] | Senior floating [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(365)	(347)
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(760)	(241)
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member] | Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(217)	(241)
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member] | Discounted Cash Flow with Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	$ (543)
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member] | Discounted Cash Flow with Inputs [Member] | Long-term debt [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	4.00%
Prepayment Speed (%)	5.00%
Severity (%)	64.00%
Spreads (%)	0.43%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member] | Discounted Cash Flow with Inputs [Member] | Long-term debt [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	5.00%
Prepayment Speed (%)	100.00%
Severity (%)	69.00%
Spreads (%)	6.56%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member] | Discounted Cash Flow with Inputs [Member] | Long-term debt [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	4.507%
Prepayment Speed (%)	99.492%
Severity (%)	66.536%
Spreads (%)	0.916%
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	$ 2,392	1,088
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Single Vendor Without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	74	54
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	2	9
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Consensus Without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	2,316	1,025
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Single-family [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Acquired property, net	1,302	1,792
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Single-family [Member] | Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Acquired property, net	44	99
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Single-family [Member] | Internal Model [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	1,806	2,816
Acquired property, net	294	476
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Single-family [Member] | Accepted Offers [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Acquired property, net	255	340
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Single-family [Member] | Appraisals [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Acquired property, net	509	571
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Single-family [Member] | Walk Forwards [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Acquired property, net	200	306
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Multifamily [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	115	198
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Multifamily [Member] | Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	0	3
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Multifamily [Member] | Broker Price Opinions [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	19	25
Acquired property, net	27	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Multifamily [Member] | Asset Manager Estimate [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	$ 96	$ 170

Fair Value Level 3 Valuation -

Fair Value Level 3 Valuation - Nonrecurring (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	$ 11,406	$ 12,057
Significant Other Observable Inputs (Level 2) [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	3,193	509
Mortgage loans held for investment, at fair value	2,828,761	2,767,813
Total assets at fair value	2,891,500	2,844,940
Significant Unobservable Inputs (Level 3) [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	2,897	2,751
Mortgage loans held for investment, at fair value	322,070	316,742
Total assets at fair value	329,662	323,739
Fair Value, Measurements, Nonrecurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	814	250
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	2,392	1,088
Total assets at fair value	5,644	5,906
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Consensus Without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	2,316	1,025
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Single Vendor Without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	74	54
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	2	9
Other assets	$ 2	$ 12
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Accepted Offers [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Number of Acquired Properties Valuated, Percentage	20.00%	19.00%
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Proprietary Home Price Model and Appraisals [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Number of Acquired Properties Valuated, Percentage	74.00%	75.00%
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Single-family [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Acquired property, net	$ 1,302	$ 1,792
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Single-family [Member] | Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Acquired property, net	44	99
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Single-family [Member] | Internal Model [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	1,806	2,816
Acquired property, net	294	476
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Single-family [Member] | Accepted Offers [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Acquired property, net	255	340
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Single-family [Member] | Appraisals [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Acquired property, net	509	571
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Single-family [Member] | Walk Forwards [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Acquired property, net	200	306
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Multifamily [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	115	198
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Multifamily [Member] | Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	0	3
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Multifamily [Member] | Broker Price Opinions [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	19	25
Acquired property, net	27	0
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Multifamily [Member] | Asset Manager Estimate [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	$ 96	$ 170

Fair Value Fair Value of Financ

Fair Value Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Fair Value Measurement [Domain]
Financial assets [Abstract]
Derivative assets, gross amount offset	$ (4,024)	$ (4,514)
Financial liabilities [Abstract]
Derivative liabilities, gross amount offset	(5,034)	(6,844)
Mortgage loans held for investment, at fair value	11,406	12,057
Derivative assets, gross amount offset	(4,024)	(4,514)
Derivative liabilities, gross amount offset	(5,034)	(6,844)
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets [Abstract]
Cash and cash equivalents and restricted cash	36,003	41,477
Federal funds sold and securities purchased under agreements to resell or similar arrangements	0	0
Trading securities	32,418	32,317
Available-for-sale securities	0	0
Mortgage loans held for sale	0	0
Mortgage loans held for investment, at fair value	0	0
Advances to lenders	0	0
Derivatives assets at fair value	0	0
Guaranty assets and buy-ups	0	0
Total financial assets	68,421	73,794
Financial liabilities [Abstract]
Federal funds purchased and securities sold under agreements to repurchase	0
Derivative liabilities at fair value	0	0
Guaranty obligations	0	0
Total financial liabilities	0	0
Significant Other Observable Inputs (Level 2) [Member]
Financial assets [Abstract]
Cash and cash equivalents and restricted cash	11,900	20,700
Federal funds sold and securities purchased under agreements to resell or similar arrangements	29,220	30,415
Trading securities	4,720	7,118
Available-for-sale securities	4,771	6,210
Mortgage loans held for sale	3,193	509
Mortgage loans held for investment, at fair value	2,828,761	2,767,813
Advances to lenders	4,659	7,156
Derivatives assets at fair value	4,276	5,019
Guaranty assets and buy-ups	0	0
Total financial assets	2,891,500	2,844,940
Financial liabilities [Abstract]
Federal funds purchased and securities sold under agreements to repurchase	7
Derivative liabilities at fair value	5,411	7,921
Guaranty obligations	0	0
Total financial liabilities	3,271,106	3,243,215
Significant Unobservable Inputs (Level 3) [Member]
Financial assets [Abstract]
Cash and cash equivalents and restricted cash	0	0
Federal funds sold and securities purchased under agreements to resell or similar arrangements	0	0
Trading securities	2,136	1,127
Available-for-sale securities	1,637	2,153
Mortgage loans held for sale	2,897	2,751
Mortgage loans held for investment, at fair value	322,070	316,742
Advances to lenders	322	352
Derivatives assets at fair value	167	182
Guaranty assets and buy-ups	433	432
Total financial assets	329,662	323,739
Financial liabilities [Abstract]
Federal funds purchased and securities sold under agreements to repurchase	0
Derivative liabilities at fair value	43	138
Guaranty obligations	523	710
Total financial liabilities	42,402	38,870
Fannie Mae [Member]
Financial liabilities [Abstract]
Long-term debt	9,008	9,582
Fannie Mae [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial liabilities [Abstract]
Short-term debt	0	0
Long-term debt	0	0
Fannie Mae [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial liabilities [Abstract]
Short-term debt	30,501	34,998
Long-term debt	280,471	298,980
Fannie Mae [Member] | Significant Unobservable Inputs (Level 3) [Member]
Financial liabilities [Abstract]
Short-term debt	0	0
Long-term debt	812	770
Consolidated Trusts [Member]
Financial liabilities [Abstract]
Long-term debt	34,866	36,524
Consolidated Trusts [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial liabilities [Abstract]
Short-term debt	0	0
Long-term debt	0	0
Consolidated Trusts [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial liabilities [Abstract]
Short-term debt	0	0
Long-term debt	2,954,716	2,901,316
Consolidated Trusts [Member] | Significant Unobservable Inputs (Level 3) [Member]
Financial liabilities [Abstract]
Short-term debt	511	584
Long-term debt	40,513	36,668
Carrying Value [Member]
Financial assets [Abstract]
Cash and cash equivalents and restricted cash	47,903	62,177
Federal funds sold and securities purchased under agreements to resell or similar arrangements	29,220	30,415
Trading securities	39,274	40,562
Available-for-sale securities	6,408	8,363
Mortgage loans held for sale	5,322	2,899
Mortgage loans held for investment, at fair value	3,120,093	3,076,854
Advances to lenders	4,965	7,494
Derivatives assets at fair value	419	687
Guaranty assets and buy-ups	148	158
Total financial assets	3,253,752	3,229,609
Financial liabilities [Abstract]
Federal funds purchased and securities sold under agreements to repurchase	7
Derivative liabilities at fair value	420	1,215
Guaranty obligations	264	280
Total financial liabilities	3,288,358	3,263,811
Carrying Value [Member] | Fannie Mae [Member]
Financial liabilities [Abstract]
Short-term debt	30,501	34,995
Long-term debt	272,619	292,102
Carrying Value [Member] | Consolidated Trusts [Member]
Financial liabilities [Abstract]
Short-term debt	511	584
Long-term debt	2,984,036	2,934,635
Estimated of Fair Value [Member]
Financial assets [Abstract]
Cash and cash equivalents and restricted cash	47,903	62,177
Federal funds sold and securities purchased under agreements to resell or similar arrangements	29,220	30,415
Trading securities	39,274	40,562
Available-for-sale securities	6,408	8,363
Mortgage loans held for sale	6,090	3,260
Mortgage loans held for investment, at fair value	3,150,831	3,084,555
Advances to lenders	4,981	7,508
Derivatives assets at fair value	419	687
Guaranty assets and buy-ups	433	432
Total financial assets	3,285,559	3,237,959
Financial liabilities [Abstract]
Federal funds purchased and securities sold under agreements to repurchase	7
Derivative liabilities at fair value	420	1,215
Guaranty obligations	523	710
Total financial liabilities	3,308,474	3,275,241
Estimated of Fair Value [Member] | Fannie Mae [Member]
Financial liabilities [Abstract]
Short-term debt	30,501	34,998
Long-term debt	281,283	299,750
Estimated of Fair Value [Member] | Consolidated Trusts [Member]
Financial liabilities [Abstract]
Short-term debt	511	584
Long-term debt	$ 2,995,229	$ 2,937,984

Fair Value Fair Value Option (D

Fair Value Fair Value Option (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Option, Quantitative Disclosures [Line Items]
Mortgage loans held for investment, at fair value	$ 11,406	$ 12,057
Fair value of nonaccrual loans	187	200
Difference between unpaid principal balance and the fair value of nonaccrual loans	33	34
Fair value of loans that are 90 days or more past due	145	152
Difference between unpaid principal balance and the fair value of these 90 days or more past due loans	$ 25	$ 25
Single-family [Member] | Minimum [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Serious delinquency, days past due	90 days	90 days
Fannie Mae [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Long-term debt, fair value	$ 9,008	$ 9,582
Consolidated Trusts [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Long-term debt, fair value	34,866	36,524
Loans [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Loans, unpaid principal balance	10,980	11,688
Long-term debt [Member] | Fannie Mae [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Long-term debt, unpaid principal balance	8,167	9,090
Long-term debt [Member] | Consolidated Trusts [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Long-term debt, unpaid principal balance	$ 31,510	$ 33,055

Fair Value Changes in FV under

Fair Value Changes in FV under the FV Option (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Fair Value, Option, Quantitative Disclosures [Line Items]
Changes in instrument-specific credit risk - Total Gains (Losses)	$ (147)	$ (150)	$ (286)	$ (189)
Other changes in fair value	(47)	(18)	(35)	(102)
Fair value gains (losses), net	(194)	(168)	(321)	(291)
Loans [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Changes in instrument-specific credit risk - Loans	26	19	53	32
Other changes in fair value	68	126	83	344
Fair value gains (losses), net	94	145	136	376
Long-term debt [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Changes in instrument-specific credit risk - Long-Term Debt	(173)	(169)	(339)	(221)
Other changes in fair value	(115)	(144)	(118)	(446)
Fair value gains (losses), net	$ (288)	$ (313)	$ (457)	$ (667)

Subsequent Events (Details)

Subsequent Events (Details) $ in Millions	Jul. 12, 2017USD ($)
Subsequent Event [Member]
Subsequent Event [Line Items]
Litigation Settlement, Amount	$ 975