Federal National Mortgage Association (FNMA) 10-Q 5 Nov 15 2015 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information	9 Months Ended
	Sep. 30, 2015shares
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	Sep. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding	1,158,082,750

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Assets:
Cash and cash equivalents	$ 19,915	$ 22,023
Restricted cash (includes $25,809 and $27,515, respectively, related to consolidated trusts)	30,281	32,542
Federal funds sold and securities purchased under agreements to resell or similar arrangements	26,600	30,950
Investments in securities:
Trading, at fair value	38,009	31,504
Available-for-sale, at fair value (includes $351 and $596, respectively, related to consolidated trusts)	22,007	30,654
Total investments in securities	60,016	62,158
Mortgage loans:
Loans held for sale, at lower of cost or fair value	3,716	331
Loans held for investment, at amortized cost	3,045,875	3,054,704
Allowance for loan losses	(29,135)	(35,541)
Total loans held for investment, net of allowance	3,016,740	3,019,163
Total mortgage loans	3,020,456	3,019,494
Accrued interest receivable, net (includes $7,371 and $7,169, respectively, related to consolidated trusts)	8,137	8,193
Acquired property, net	7,691	10,618
Deferred tax assets, net	39,012	42,206
Other assets	18,674	19,992
Total assets	3,230,782	3,248,176
Liabilities:
Accrued interest payable (includes $8,156 and $8,282, respectively, related to consolidated trusts)	10,016	10,232
Federal funds purchased and securities sold under agreements to repurchase	118	50
Other liabilities (includes $426 and $503, respectively, related to consolidated trusts)	10,400	12,019
Total liabilities	3,226,779	3,244,456
Commitments and contingencies (Note 16)	0	0
Fannie Mae 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 and 1,158,082,750 shares outstanding	687	687
Accumulated deficit	(127,206)	(127,618)
Accumulated other comprehensive income	1,613	1,733
Treasury stock, at cost, 150,679,953 shares	(7,401)	(7,401)
Total Fannie Mae stockholders’ equity	3,972	3,680
Noncontrolling interest	31	40
Total equity (See Note 1: Impact of U.S. Government Support for information on our dividend obligation to Treasury)	4,003	3,720
Total liabilities and equity	3,230,782	3,248,176
Fannie Mae [Member]
Mortgage loans:
Loans held for investment, at amortized cost	241,294	272,360
Allowance for loan losses	(27,655)	(33,117)
Total mortgage loans	217,324	239,549
Liabilities:
Debt (includes $9,975 and $6,403, respectively, of debt of Fannie Mae at fair value and $23,143 and $19,483, respectively, of debt of consolidated trusts, at fair value)	417,458	460,443
Consolidated Trusts [Member]
Assets:
Restricted cash (includes $25,809 and $27,515, respectively, related to consolidated trusts)	25,809	27,515
Investments in securities:
Available-for-sale, at fair value (includes $351 and $596, respectively, related to consolidated trusts)	351	596
Mortgage loans:
Loans held for investment, at amortized cost	2,804,581	2,782,344
Allowance for loan losses	(1,480)	(2,424)
Total mortgage loans	2,803,132	2,779,945
Accrued interest receivable, net (includes $7,371 and $7,169, respectively, related to consolidated trusts)	7,371	7,169
Liabilities:
Accrued interest payable (includes $8,156 and $8,282, respectively, related to consolidated trusts)	8,156	8,282
Debt (includes $9,975 and $6,403, respectively, of debt of Fannie Mae at fair value and $23,143 and $19,483, respectively, of debt of consolidated trusts, at fair value)	2,788,787	2,761,712
Other liabilities (includes $426 and $503, respectively, related to consolidated trusts)	$ 426	$ 503

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Assets:
Restricted cash (includes $25,809 and $27,515, respectively, related to consolidated trusts)	$ 30,281	$ 32,542
Investments in securities:
Available-for-sale, at fair value (includes $351 and $596, respectively, related to consolidated trusts)	22,007	30,654
Mortgage loans:
Mortgage loans held for investment, at fair value	14,605	15,629
Accrued interest receivable, net (includes $7,371 and $7,169, respectively, related to consolidated trusts)	8,137	8,193
Liabilities:
Accrued interest payable (includes $8,156 and $8,282, respectively, related to consolidated trusts)	10,016	10,232
Other liabilities (includes $426 and $503, respectively, related to consolidated trusts)	$ 10,400	$ 12,019
Fannie Mae 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, 1,158,082,750 shares outstanding	1,158,082,750	1,158,082,750
Treasury stock, at cost, 150,679,953 shares	150,679,953	150,679,953
Consolidated Trusts [Member]
Assets:
Restricted cash (includes $25,809 and $27,515, respectively, related to consolidated trusts)	$ 25,809	$ 27,515
Investments in securities:
Available-for-sale, at fair value (includes $351 and $596, respectively, related to consolidated trusts)	351	596
Mortgage loans:
Accrued interest receivable, net (includes $7,371 and $7,169, respectively, related to consolidated trusts)	7,371	7,169
Liabilities:
Accrued interest payable (includes $8,156 and $8,282, respectively, related to consolidated trusts)	8,156	8,282
Debt at fair value	23,143	19,483
Other liabilities (includes $426 and $503, respectively, related to consolidated trusts)	426	503
Fannie Mae [Member]
Liabilities:
Debt at fair value	$ 9,975	$ 6,403

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Interest income:
Trading securities	$ 99	$ 151	$ 330	$ 421
Available-for-sale securities	261	395	931	1,249
Mortgage loans (includes $24,537 and $25,217, respectively, for the three months ended and $73,426 and $76,704, respectively, for the nine months ended related to consolidated trusts)	26,980	27,779	80,706	84,532
Other	37	29	104	77
Total interest income	27,377	28,354	82,071	86,279
Interest expense:
Short-term debt	37	26	99	67
Long-term debt (includes $19,891 and $21,094, respectively, for the three months ended and $59,934 and $64,862, respectively, for the nine months ended related to consolidated trusts)	21,752	23,144	65,640	71,386
Total interest expense	21,789	23,170	65,739	71,453
Net interest income	5,588	5,184	16,332	14,826
Benefit for credit losses	1,550	1,085	1,050	3,498
Net interest income after benefit for credit losses	7,138	6,269	17,382	18,324
Non-interest income (loss)
Investment gains, net	299	171	1,155	749
Fair value losses, net	(2,589)	(207)	(1,902)	(2,331)
Debt extinguishment gains (losses), net	(11)	11	0	49
Fee and other income	259	826	1,123	5,564
Non-interest income (loss)	(2,042)	801	376	4,031
Administrative expenses:
Salaries and employee benefits	317	337	999	981
Professional services	219	263	741	780
Occupancy expenses	43	47	129	144
Other administrative expenses	373	59	495	170
Total administrative expenses	952	706	2,364	2,075
Foreclosed property expense (income)	497	249	1,152	(227)
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees	413	351	1,192	1,008
Other expenses, net	204	72	412	479
Total expenses	2,066	1,378	5,120	3,335
Income before federal income taxes	3,030	5,692	12,638	19,020
Provision for federal income taxes	(1,070)	(1,787)	(4,150)	(6,123)
Net income	1,960	3,905	8,488	12,897
Other comprehensive income (loss):
Changes in unrealized gains on available-for-sale securities, net of reclassification adjustments and taxes	(177)	63	(548)	480
Other	430	32	428	32
Total other comprehensive income (loss)	253	95	(120)	512
Total comprehensive income	2,213	4,000	8,368	13,409
Less: Comprehensive income attributable to noncontrolling interest	0	0	0	(1)
Total comprehensive income attributable to Fannie Mae	2,213	4,000	8,368	13,408
Less: Net income attributable to noncontrolling interest	0	0	0	(1)
Net income attributable to Fannie Mae	1,960	3,905	8,488	12,896
Dividends distributed or available for distribution to senior preferred stockholder (Note 10)	(2,202)	(3,999)	(8,357)	(13,403)
Net income (loss) attributable to common stockholders (Note 10)	$ (242)	$ (94)	$ 131	$ (507)
Earnings (loss) per share, Basic (in dollars per share)	$ (0.04)	$ (0.02)	$ 0.02	$ (0.09)
Earnings (loss) per share, Diluted (in dollars per share)	$ (0.04)	$ (0.02)	$ 0.02	$ (0.09)
Weighted-average common shares outstanding, Basic	5,762	5,762	5,762	5,762
Weighted-average common shares outstanding, Diluted	5,762	5,762	5,893	5,762

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Operations and Comprehensive Income (Parenthetical) (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Mortgage loans interest income	$ 26,980	$ 27,779	$ 80,706	$ 84,532
Long-term debt interest expense	21,752	23,144	65,640	71,386
Consolidated Trusts [Member]
Mortgage loans interest income	24,537	25,217	73,426	76,704
Long-term debt interest expense	$ 19,891	$ 21,094	$ 59,934	$ 64,862

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Net cash provided by (used in) operating activities
Net cash provided by (used in) operating activities	$ (6,375)	$ 960
Cash flows provided by investing activities:
Proceeds from maturities and paydowns of trading securities held for investment	633	1,046
Proceeds from sales of trading securities held for investment	1,028	1,241
Proceeds from maturities and paydowns of available-for-sale securities	3,477	4,505
Proceeds from sales of available-for-sale securities	6,919	2,461
Purchases of loans held for investment	(146,577)	(93,029)
Net change in restricted cash	2,261	477
Advances to lenders	(92,345)	(71,268)
Proceeds from disposition of acquired property and preforeclosure sales	16,306	19,533
Net change in federal funds sold and securities purchased under agreements to resell or similar arrangements	4,350	9,525
Other, net	103	(178)
Net cash provided by investing activities	193,784	175,865
Cash flows used in financing activities:
Payments of cash dividends on senior preferred stock to Treasury	(8,075)	(16,594)
Other, net	68	25
Net cash used in financing activities	(189,517)	(179,724)
Net decrease in cash and cash equivalents	(2,108)	(2,899)
Cash and cash equivalents at beginning of period	22,023	19,228
Cash and cash equivalents at end of period	19,915	16,329
Cash paid during the period for:
Interest	78,584	81,947
Income Taxes	470	2,475
Fannie Mae [Member]
Cash flows provided by investing activities:
Proceeds from repayments and sales of loans acquired as held for investment of Fannie Mae	21,460	19,765
Cash flows used in financing activities:
Proceeds from issuance of debt	337,748	284,266
Payments to redeem debt	(381,487)	(339,528)
Consolidated Trusts [Member]
Cash flows provided by investing activities:
Proceeds from repayments and sales of loans acquired as held for investment of consolidated trusts	376,169	281,787
Cash flows used in financing activities:
Proceeds from issuance of debt	259,254	188,719
Payments to redeem debt	$ (397,025)	$ (296,612)

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2015
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, what form we will have, 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 in 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 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 or our status as a GSE could materially and adversely affect 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. We have received a total of $116.1 billion from Treasury pursuant to the senior preferred stock purchase agreement as of September 30, 2015 . The aggregate liquidation preference of the senior preferred stock, including the initial aggregate liquidation preference of $1.0 billion , was $117.1 billion as of September 30, 2015 . As of September 30, 2015 , the amount of remaining funding available to us under the senior preferred stock purchase agreement was $117.6 billion . Based on the terms of the senior preferred stock, we paid Treasury a dividend of $4.4 billion on September 30, 2015 based on our net worth of $6.2 billion as of June 30, 2015 less the applicable capital reserve of $1.8 billion . We expect to pay Treasury an additional dividend of $2.2 billion by December 31, 2015 based on our net worth of $4.0 billion as of September 30, 2015 less the applicable capital reserve amount of $ 1.8 billion . The capital reserve amount was $2.4 billion for dividend periods in 2014. The capital reserve amount will continue to be reduced by $600 million each year until it reaches zero on January 1, 2018. Basis of Presentation The accompanying unaudited interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“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 nine months ended September 30, 2015 may not necessarily be indicative of the results for the year ending December 31, 2015. The unaudited interim condensed consolidated financial statements as of and for the nine months ended September 30, 2015 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, 2014 (“2014 Form 10-K”), filed with the SEC on February 20, 2015. Changes in Accounting Principle—Nonaccrual Loans Effective January 1, 2015, we changed our policy for the treatment of interest previously accrued but not collected at the date both single-family and multifamily loans are placed on nonaccrual status. Specifically, interest previously accrued but not collected will be reversed through interest income at the date a loan is placed on nonaccrual status. Previously, when a loan was placed on nonaccrual status, interest previously accrued but not collected became part of each loan’s recorded investment and was reviewed either individually or collectively for impairment. We also changed our policy for when a non-modified single-family loan is returned to accrual status. Effective January 1, 2015, a non-modified single-family loan will be returned to accrual status at the point that the borrower brings the loan current. Previously, a non-modified single-family loan was returned to accrual status at the point that the borrower had made sufficient payments to reduce the delinquency status below our nonaccrual threshold of 60 days past due. We have concluded that these changes in accounting principle are preferable as we align our nonaccrual policy with industry practice. This alignment increases comparability of our financial statements to these entities, resulting in improved financial reporting. As these changes to our nonaccrual policy were not material to our financial statements, we wrote off the accrued interest receivable balance on our nonaccrual loans, as well as the corresponding allowance that related to that interest, as an adjustment to the 2015 provision for loan losses and did not retrospectively adjust the condensed consolidated financial statements for this change. Change in Accounting Principle—Loans Held for Sale Effective January 1, 2015, we changed our policy for calculating the lower of cost or fair value adjustment on loans that have been designated as held for sale (“HFS”). Specifically, our lower of cost or fair value calculation will be performed at an individual loan level on the date of redesignation, if previously held for investment (“HFI”), and for all subsequent periods in which a loan is classified as HFS. Previously, the initial lower of cost or fair value adjustment on the date of re-designation was calculated at a loan level whereas the subsequent lower of cost or fair value adjustments were calculated at a pool level. We have concluded that this change in accounting policy is preferable as it will align the unit of account that is used for both the initial and subsequent lower of cost or market measurements on our HFS portfolio. Additionally, by performing the lower of cost or fair value calculation at the loan level, the adjustment will be calculated on a more disaggregated basis. As this change in accounting policy is not material to our financial statements, we recorded the impact of this change in accounting principle as an adjustment to 2015 fair value losses, net and did not retrospectively adjust the condensed consolidated financial statements for this change. Regulatory Capital FHFA has announced that, during the conservatorship, our existing statutory and FHFA-directed regulatory capital requirements will not be binding and that 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 $140.6 billion as of September 30, 2015 and $142.2 billion as of December 31, 2014 . 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 directs 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 September 30, 2015 , Treasury held an investment in our senior preferred stock with an aggregate liquidation preference of $117.1 billion . FHFA’s control of Fannie Mae and Freddie Mac has caused us, FHFA and Freddie Mac to be deemed related parties. Our administrative expenses were reduced by $18 million for the three months ended September 30, 2015 and 2014 and $50 million and $55 million for the nine months ended September 30, 2015 and 2014 , 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. During the three and nine months ended September 30, 2015 , we made tax payments of $100 million and $470 million , respectively, to the Internal Revenue Service (“IRS”), a bureau of Treasury. We did not make any tax payments during the three months ended September 30, 2014 . We made tax payments of $2.5 billion during the nine months ended September 30, 2014 . We received a refund of $277 million from the IRS during the nine months ended September 30, 2015 for income tax adjustments related to tax years 2004 through 2010. Under the temporary credit and liquidity facilities (“TCLF”) program, we had no outstanding standby credit and liquidity support as of September 30, 2015 . We had $390 million outstanding, which includes principal and interest, of standby credit and liquidity support as of December 31, 2014 . Under the new issue bond (“NIB”) program, we had $3.9 billion and $4.2 billion outstanding of pass-through securities backed by single-family and multifamily housing bonds issued by housing finance agencies (“HFAs”) as of September 30, 2015 and December 31, 2014 , respectively. Treasury will bear the initial losses of principal under the TCLF program and the NIB program up to 35% of the total original principal on a combined program-wide basis, and thereafter we will bear the losses of principal that are attributable to the TCLF and the securities we have issued. Treasury will also bear any losses of unpaid interest under the two programs. As of September 30, 2015 , there had been no losses of principal or interest under the TCLF program or 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 $413 million and $351 million in TCCA fees during the three months ended September 30, 2015 and 2014 , respectively, and $1.2 billion and $1.0 billion for the nine months ended September 30, 2015 and 2014 , respectively, of which $413 million had not been remitted to Treasury as of September 30, 2015 . For the three and nine months ended September 30, 2015 , we accrued, but have not yet paid, $56 million and $168 million , respectively, in expenses in connection with certain funding obligations under the GSE Act, a portion of which is attributable to Treasury’s Capital Magnet Fund. 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 total new business purchases for the three and nine months ended September 30, 2015 . As of September 30, 2015 and December 31, 2014 , we held Freddie Mac mortgage-related securities with a fair value of $6.1 billion and $6.9 billion , respectively. We recognized interest income on these securities held by us of $55 million and $68 million for the three months ended September 30, 2015 and 2014 , respectively, and $174 million and $219 million for the nine months ended September 30, 2015 and 2014 , respectively. In addition, Freddie Mac may be an investor in variable interest entities that we have consolidated, and we may be an investor in variable interest entities that Freddie Mac has consolidated. 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 $28 million and $26 million for the three months ended September 30, 2015 and 2014 , respectively, and $84 million and $80 million for the nine months ended September 30, 2015 and 2014 , respectively. Fannie Mae and Freddie Mac established Common Securitization Solutions, LLC (“CSS”), a jointly owned limited liability company, to operate a common securitization platform. During the three and nine months ended September 30, 2015 , we contributed $17 million and $47 million , respectively, of capital into CSS, and we made no contributions for the three and nine months ended September 30, 2014 . No other transactions outside of normal business activities have occurred between us and Freddie Mac during the nine months ended September 30, 2015 or 2014. 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 and other assets and liabilities, recoverability of our deferred tax assets and allowance for loan losses. Actual results could be different from these estimates. In April 2012, FHFA issued Advisory Bulletin AB 2012-02, “Framework for Adversely Classifying Loans, Other Real Estate Owned, and Other Assets and Listing Assets for Special Mention” (the “Advisory Bulletin”), which prescribes, among other things, classification of loans by risk category and provides guidance on when a loan should be charged off. The provisions of the Advisory Bulletin led us to re-evaluate our estimate of when a loan is deemed uncollectible. For the vast majority of our delinquent single-family loans, we will continue to charge off the loan at the date of foreclosure or other liquidation event (such as a deed-in-lieu of foreclosure or a short sale). For a relatively small subset of delinquent loans deemed to be uncollectible prior to foreclosure based upon our historical data, we charge off the portion of the loan (including preforeclosure property taxes and insurance receivable that pertain to such loans) deemed to be uncollectible prior to the date of foreclosure or other liquidation event, which given our current credit analytics and historical data, is when the loans are excessively delinquent and the outstanding loan balance exceeds the fair value of the underlying property. This change in estimate resulted in the recognition on January 1, 2015 of (1) $1.8 billion in charge-offs of HFI loans, (2) $ 724 million in charge-offs of preforeclosure property taxes and insurance receivable and (3) a reduction to our allowance for loan losses and our allowance for preforeclosure property taxes and insurance receivable in amounts equal to charge-offs recognized in connection with HFI loans and preforeclosure property taxes and insurance receivable. We continue to enhance our data collection and analysis efforts to further refine our loss estimates as we obtain incremental information on the performance of our loans. Fee and Other Income Fee and other income includes transaction fees, multifamily fees, technology fees and other miscellaneous income. During the three and nine months ended September 30, 2014 , we recognized $538 million and $4.8 billion , respectively, in “Fee and other income” in our condensed consolidated statement of operations and comprehensive income resulting from settlement agreements resolving certain lawsuits relating to private-label mortgage-related securities (“PLS”) sold to us. There were no settlement agreements resolving PLS lawsuits during the three and nine months ended September 30, 2015 . Employee Retirement Benefits In 2013, our defined benefit pension plans were amended to cease the accrual of benefits for all employees and the plans were subsequently terminated, effective December 31, 2013. The additional cost of the termination, including the estimated premium required to purchase annuity contracts, was recognized in “Other comprehensive income” in our condensed consolidated statement of operations and comprehensive income for the year ended December 31, 2013. During the three months ended September 30, 2015, we settled our defined pension benefit obligations. We transferred plan assets to an annuity provider and distributed lump sum payments to participants based on their elections. We made a cash contribution of $102 million to settle the plans. The actuarial losses of $305 million , previously recorded in “Accumulated other comprehensive income,” were recognized in “Administrative expenses” and the associated tax amounts were recognized in “Provision for federal income taxes” in our condensed consolidated statements of operations and comprehensive income for the three and nine months ended September 30, 2015 . New Accounting Guidance Effective January 1, 2015, we prospectively adopted guidance issued by the Financial Accounting Standards Board (“FASB”) clarifying when a creditor is considered to have received physical possession of residential real estate property collateralized by a consumer mortgage loan. The adoption of this guidance resulted in a clarification to our policy to align our definition of when we have taken physical possession of real estate with the new guidance; however it did not impact the timing of derecognition of loan receivable and recognition of real estate property in our financial statements. The new guidance also requires us to disclose the recorded investment in consumer mortgage loans collateralized by residential real estate property that are in the process of foreclosure. See “Note 3 , Mortgage Loans ” for additional information regarding the disclosure required upon adoption of this guidance. Effective January 1, 2015, we prospectively adopted guidance issued by the FASB related to the classification of government guaranteed mortgage loans upon foreclosure. The impact of the adoption was not material to the condensed consolidated balance sheets. In February 2015, the FASB issued guidance regarding consolidation of legal entities such as limited partnerships, limited liability corporations and securitization structures. The guidance removes the specialized consolidation model surrounding limited partnerships and similar entities and amends the requirements that such entities must meet to qualify as voting interest entities. In addition, the guidance eliminates certain of the conditions for evaluating whether fees paid to a decision maker or service provider represent a variable interest. The new guidance is effective for us on January 1, 2016 with early adoption permitted. We are currently evaluating the potential impact of the new guidance on our consolidated financial statements.

Consolidations and Transfers of

Consolidations and Transfers of Financial Assets	9 Months Ended
	Sep. 30, 2015
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 variable interest entities (“VIEs”). The primary types of entities are securitization trusts guaranteed by us via lender swap and portfolio securitization transactions and mortgage-backed trusts that were not created by us, as well as housing partnerships that are established to finance the acquisition, construction, development or rehabilitation of affordable multifamily and single-family housing. 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 mortgage-backed trusts, as well as our maximum exposure to loss and the total assets of these unconsolidated mortgage-backed trusts. As of September 30, 2015 December 31, 2014 (Dollars in millions) Assets and liabilities recorded in our condensed consolidated balance sheets related to mortgage-backed trusts: Assets: Trading securities: Fannie Mae securities $ 4,977 $ 4,790 Non-Fannie Mae securities 5,933 7,073 Total trading securities 10,910 11,863 Available-for-sale securities: Fannie Mae securities 3,931 5,043 Non-Fannie Mae securities 16,259 22,776 Total available-for-sale securities 20,190 27,819 Other assets 102 111 Other liabilities (755 ) (1,440 ) Net carrying amount $ 30,447 $ 38,353 Maximum exposure to loss $ 36,637 $ 45,311 Total assets of unconsolidated mortgage-backed trusts $ 252,211 $ 253,554 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 total assets of our unconsolidated limited partnership investments were $4.9 billion and $5.8 billion as of September 30, 2015 and December 31, 2014 , respectively. 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 September 30, 2015 and 2014 , the unpaid principal balance of portfolio securitizations was $55.4 billion and $44.2 billion , respectively. For the nine months ended September 30, 2015 and 2014 , the unpaid principal balance of portfolio securitizations was $166.3 billion and $113.1 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 September 30, 2015 , the unpaid principal balance of retained interests was $5.4 billion and its related fair value was $6.7 billion . The unpaid principal balance of retained interests was $6.3 billion and its related fair value was $7.6 billion as of December 31, 2014. For the three months ended September 30, 2015 and 2014 , the principal and interest received on retained interests was $273 million and $386 million , respectively. For the nine months ended September 30, 2015 and 2014 , the principal and interest received on retained interests was $919 million and $1.1 billion , 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 $1.6 billion and $1.8 billion as of September 30, 2015 and December 31, 2014 , respectively. For information on our on-balance sheet mortgage loans, see “ Note 3, Mortgage Loans .”

Mortgage Loans

Mortgage Loans	9 Months Ended
	Sep. 30, 2015
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 HFI or 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 our condensed consolidated statements of operations and comprehensive income. We report the recorded investment of HFI loans at the 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 guaranteed or insured, in whole or in part, by the U.S. government or one of its agencies, 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 September 30, 2015 December 31, 2014 Of Fannie Mae Of Consolidated Trusts Total Of Fannie Mae Of Consolidated Trusts Total (Dollars in millions) Single-family $ 242,496 $ 2,573,388 $ 2,815,884 $ 262,116 $ 2,569,884 $ 2,832,000 Multifamily 15,272 181,533 196,805 23,255 164,045 187,300 Total unpaid principal balance of mortgage loans 257,768 2,754,921 3,012,689 285,371 2,733,929 3,019,300 Cost basis and fair value adjustments, net (12,789 ) 49,691 36,902 (12,705 ) 48,440 35,735 Allowance for loan losses for loans held for investment (27,655 ) (1,480 ) (29,135 ) (33,117 ) (2,424 ) (35,541 ) Total mortgage loans $ 217,324 $ 2,803,132 $ 3,020,456 $ 239,549 $ 2,779,945 $ 3,019,494 During the three months ended September 30, 2015 , we redesignated loans with a carrying value of $1.3 billion from HFI to HFS. There were no redesignations from HFI to HFS during the three months ended September 30, 2014. During the nine months ended September 30, 2015 and 2014 , we redesignated loans with a carrying value of $5.9 billion and $2.2 billion , respectively, from HFI to HFS. During the three and nine months ended September 30, 2014 , we redesignated loans with a carrying value of $240 million and $ 241 million , respectively from HFS to HFI. We sold loans with an unpaid principal balance of $1.9 billion and $2.5 billion during the three and nine months ended September 30, 2015 , respectively. We sold loans with an unpaid principal balance of $1.9 billion during the nine months ended September 30, 2014 . There were no sales of loans during the three months ended September 30, 2014 . The recorded investment of single-family mortgage loans for which formal foreclosure proceedings are in process was $27.6 billion as of September 30, 2015 . 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 Policy We discontinue accruing interest on loans when we believe collectability 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. We generally place a multifamily loan on nonaccrual status when the loan is deemed to be individually impaired, unless the loan is well secured such that collectability of principal and accrued interest is reasonably assured. Effective January 1, 2015, we changed our policy for the treatment of interest previously accrued but not collected at the date both single-family and multifamily loans are placed on nonaccrual status. Specifically, interest previously accrued but not collected will be reversed through interest income at the date a loan is placed on nonaccrual status. Previously, when a loan was placed on nonaccrual status, interest previously accrued but not collected became part of the loan’s recorded investment and was reviewed either individually or collectively for impairment. We also changed our policy for when a non-modified single-family loan is returned to accrual status. Effective January 1, 2015, a non-modified single-family loan will be returned to accrual status at the point that the borrower brings the loan current. Previously, a non-modified single-family loan was returned to accrual status at the point that the borrower had made sufficient payments to reduce their delinquency status below our nonaccrual threshold of 60 days past due. We did not change our policy for returning modified single-family loans to accrual status. We return modified single-family loans to accrual status at the point that the borrower successfully makes all required payments during the trial period (generally three to four months) and modification is made permanent. See “Note 1, Summary of Significant Accounting Policies” for additional information on such changes in accounting policy. Changes to our nonaccrual policy were limited to those described above. For most single-family loans, we continue to recognize interest income for loans on nonaccrual status when cash is received. However, if a single-family loan was charged off prior to foreclosure, all payments received are applied on a cost recovery basis to reduce principal on the mortgage loan. We stop applying the cost recovery approach on those single-family loans when they are brought current either through borrower payments or modification and there has been a sufficient performance period to demonstrate that the borrower has the ability and intent to make the remaining payments on their mortgage loans. For multifamily loans, we apply any payment received on a cost recovery basis to reduce principal on the mortgage loan unless the loan is determined to be well secured. We generally return a multifamily loan to accrual status and stop applying the cost recovery approach when the borrower cures the delinquency of the loan or we otherwise determine that the loan is well secured such that collectability 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 September 30, 2015 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 $ 29,574 $ 7,766 $ 28,417 $ 65,757 $ 2,594,488 $ 2,660,245 $ 49 $ 36,108 Government (2) 57 25 295 377 41,342 41,719 295 — Alt-A 4,126 1,291 7,407 12,824 87,525 100,349 7 8,690 Other 1,562 489 2,447 4,498 33,730 38,228 7 2,922 Total single-family 35,319 9,571 38,566 83,456 2,757,085 2,840,541 358 47,720 Multifamily (3) 37 N/A 88 125 198,574 198,699 — 679 Total $ 35,356 $ 9,571 $ 38,654 $ 83,581 $ 2,955,659 $ 3,039,240 $ 358 $ 48,399 As of December 31, 2014 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 $ 29,130 $ 8,396 $ 38,248 $ 75,774 $ 2,580,446 $ 2,656,220 $ 55 $ 46,556 Government (2) 63 26 305 394 44,927 45,321 305 — Alt-A 4,094 1,414 11,603 17,111 95,650 112,761 8 13,007 Other 1,520 516 3,763 5,799 38,460 44,259 6 4,259 Total single-family 34,807 10,352 53,919 99,078 2,759,483 2,858,561 374 63,822 Multifamily (3) 60 N/A 89 149 189,084 189,233 — 823 Total $ 34,867 $ 10,352 $ 54,008 $ 99,227 $ 2,948,567 $ 3,047,794 $ 374 $ 64,645 __________ (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 September 30, 2015 (1) December 31, 2014 (1) Primary Alt-A Other Primary Alt-A Other (Dollars in millions) Estimated mark-to-market loan-to-value ratio: (2) Less than or equal to 80% $ 2,248,367 $ 61,367 $ 22,263 $ 2,156,165 $ 60,851 $ 22,558 Greater than 80% and less than or equal to 90% 240,860 13,188 5,197 261,709 15,151 6,046 Greater than 90% and less than or equal to 100% 108,540 9,758 4,020 140,778 12,490 5,236 Greater than 100% and less than or equal to 110% 28,684 6,528 2,787 43,014 8,998 3,900 Greater than 110% and less than or equal to 120% 15,115 4,018 1,699 23,439 6,033 2,615 Greater than 120% and less than or equal to 125% 4,706 1,295 552 7,529 2,114 904 Greater than 125% 13,973 4,195 1,710 23,586 7,124 3,000 Total $ 2,660,245 $ 100,349 $ 38,228 $ 2,656,220 $ 112,761 $ 44,259 __________ (1) Excludes $41.7 billion and $45.3 billion as of September 30, 2015 and December 31, 2014 , 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 loan-to-value (“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 September 30, December 31, 2015 2014 (Dollars in millions) Credit risk profile by internally assigned grade: (1) Pass $ 192,767 $ 182,079 Special Mention 2,725 3,070 Substandard 3,203 3,842 Doubtful 4 242 Total $ 198,699 $ 189,233 _________ (1) Pass (loan is current and adequately protected by the current financial strength and debt service capacity of the borrower); special mention (loan with signs of potential weakness); substandard (loan with a well defined weakness that jeopardizes the timely full repayment); and doubtful (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. 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 September 30, 2015 December 31, 2014 Unpaid Principal Balance Total Recorded Investment Related Allowance for Loan Losses Unpaid Principal Balance Total Recorded Investment Related Allowance for Loan Losses Related Allowance for Accrued Interest Receivable (Dollars in millions) Individually impaired loans: With related allowance recorded: Single-family: Primary $ 118,495 $ 112,430 $ 17,374 $ 125,960 $ 120,221 $ 20,327 $ 309 Government 324 329 62 281 285 46 12 Alt-A 32,593 29,777 6,454 35,492 32,816 7,778 136 Other 13,217 12,489 2,514 14,667 13,947 3,049 38 Total single-family 164,629 155,025 26,404 176,400 167,269 31,200 495 Multifamily 788 793 113 1,230 1,241 175 6 Total individually impaired loans with related allowance recorded 165,417 155,818 26,517 177,630 168,510 31,375 501 With no related allowance recorded: (1) Single-family: Primary 16,930 15,600 — 16,704 14,876 — — Government 60 56 — 61 57 — — Alt-A 4,235 3,580 — 3,993 3,119 — — Other 1,356 1,218 — 1,240 1,056 — — Total single-family 22,581 20,454 — 21,998 19,108 — — Multifamily 364 366 — 565 568 — — Total individually impaired loans with no related allowance recorded 22,945 20,820 — 22,563 19,676 — — Total individually impaired loans (2) $ 188,362 $ 176,638 $ 26,517 $ 200,193 $ 188,186 $ 31,375 $ 501 For the Three Months Ended September 30, 2015 2014 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 $ 113,634 $ 1,090 $ 71 $ 121,246 $ 1,077 $ 111 Government 299 3 — 285 3 — Alt-A 30,041 272 14 33,458 268 24 Other 12,652 95 6 14,346 100 8 Total single-family 156,626 1,460 91 169,335 1,448 143 Multifamily 878 9 — 1,540 17 — Total individually impaired loans with related allowance recorded 157,504 1,469 91 170,875 1,465 143 With no related allowance recorded: (1) Single-family: Primary 15,627 279 16 14,442 226 56 Government 53 1 — 55 1 — Alt-A 3,674 64 1 2,887 51 14 Other 1,259 21 — 1,008 16 3 Total single-family 20,613 365 17 18,392 294 73 Multifamily 386 5 — 1,572 18 — Total individually impaired loans with no related allowance recorded 20,999 370 17 19,964 312 73 Total individually impaired loans (2) $ 178,503 $ 1,839 $ 108 $ 190,839 $ 1,777 $ 216 For the Nine Months Ended September 30, 2015 2014 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 $ 115,762 $ 3,152 $ 248 $ 122,443 $ 3,264 $ 372 Government 290 9 — 266 9 — Alt-A 30,760 774 41 33,926 805 74 Other 13,030 282 15 14,635 305 28 Total single-family 159,842 4,217 304 171,270 4,383 474 Multifamily 1,053 15 — 1,813 63 — Total individually impaired loans with related allowance recorded 160,895 4,232 304 173,083 4,446 474 With no related allowance recorded: (1) Single-family: Primary 15,967 779 76 13,514 616 157 Government 55 3 — 70 4 — Alt-A 3,720 158 8 2,687 135 34 Other 1,287 56 2 945 40 8 Total single-family 21,029 996 86 17,216 795 199 Multifamily 463 8 — 1,698 58 — Total individually impaired loans with no related allowance recorded 21,492 1,004 86 18,914 853 199 Total individually impaired loans (2) $ 182,387 $ 5,236 $ 390 $ 191,997 $ 5,299 $ 673 __________ (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 $174.6 billion and $185.2 billion as of September 30, 2015 and December 31, 2014 respectively. Includes multifamily loans restructured in a TDR with a recorded investment of $490 million and $716 million as of September 30, 2015 and December 31, 2014 , respectively. (3) Total single-family interest income recognized of $1.8 billion for the three months ended September 30, 2015 and 2014 consists of $1.5 billion and $1.4 billion of contractual interest, respectively, and $327 million and $297 million of effective yield adjustments, respectively. Total single-family interest income recognized of $5.2 billion for the nine months ended September 30, 2015 and 2014 consists of $4.3 billion of contractual interest for both periods and $907 million and $857 million of effective yield adjustments, respectively. 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. In addition to formal loan modifications, we also engage in other loss mitigation activities with troubled borrowers, which include repayment plans and forbearance arrangements, both of which represent informal agreements with the borrower that do not result in the legal modification of the loan’s contractual terms. We account for these informal restructurings as a TDR if we defer more than three missed payments. We also classify loans to certain borrowers who have received bankruptcy relief as TDRs. 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 September 30, 2015 and 2014 , the average term extension of a single-family modified loan was 159 months and 162 months , respectively, and the average interest rate reduction was 0.69 and 0.89 percentage points, respectively. During the nine months ended September 30, 2015 and 2014 , the average extension of a single-family modified loan was 161 months for both periods and the average interest rate reduction was 0.75 and 1.04 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 September 30, 2015 2014 Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 14,926 $ 2,021 23,057 $ 3,270 Government 54 6 91 12 Alt-A 1,805 268 3,175 521 Other 324 57 698 142 Total single-family 17,109 2,352 27,021 3,945 Multifamily 3 10 7 811 Total troubled debt restructurings 17,112 $ 2,362 27,028 $ 4,756 For the Nine Months Ended September 30, 2015 2014 Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 54,284 $ 7,443 76,831 $ 10,944 Government 192 22 264 33 Alt-A 7,127 1,101 11,231 1,875 Other 1,453 265 2,608 540 Total single-family 63,056 8,831 90,934 13,392 Multifamily 7 16 16 849 Total troubled debt restructurings 63,063 $ 8,847 90,950 $ 14,241 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 September 30, 2015 2014 Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 6,847 $ 1,003 8,798 $ 1,312 Government 31 3 38 6 Alt-A 1,052 183 1,372 241 Other 328 65 438 100 Total single-family 8,258 1,254 10,646 1,659 Multifamily — — 1 5 Total TDRs that subsequently defaulted 8,258 $ 1,254 10,647 $ 1,664 For the Nine Months Ended September 30, 2015 2014 Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 19,726 $ 2,870 25,586 $ 3,873 Government 88 12 74 9 Alt-A 3,168 537 4,212 753 Other 922 186 1,362 304 Total single-family 23,904 3,605 31,234 4,939 Multifamily 3 6 6 22 Total TDRs that subsequently defaulted 23,907 $ 3,611 31,240 $ 4,961

Allowance for Loan Losses

Allowance for Loan Losses	9 Months Ended
	Sep. 30, 2015
Loans and Leases Receivable, Allowance [Abstract]
Allowance for Loan Losses	Allowance for Loan Losses Our allowance for loan losses is a valuation allowance that reflects an estimate of incurred credit losses related to our recorded investment in both single-family and multifamily HFI loans. This population includes both HFI loans held by Fannie Mae and by consolidated Fannie Mae MBS trusts. When calculating our allowance for loan losses, we consider only our net recorded investment in the loan at the balance sheet date, which includes the loan’s unpaid principal balance and any applicable cost basis adjustments. We record charge-offs as a reduction to the allowance for loan losses when losses are confirmed through the receipt of assets in full satisfaction of a loan, such as the underlying collateral upon foreclosure or cash upon completion of a short sale. Additionally, we record charge-offs as a reduction to our allowance for loan losses when a loan is determined to be uncollectible and upon the redesignation of nonperforming loans from HFI to HFS. 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. 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. When a loan has been restructured, we measure impairment using a cash flow analysis discounted at the loan’s original effective interest rate. However, 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 and other credit enhancements. 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. We establish a collective loss reserve 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. The following tables display changes in single-family, multifamily and total allowance for loan losses. For the Three Months Ended September 30, 2015 2014 Of Fannie Mae Of Consolidated Trusts Total Of Fannie Mae Of Consolidated Trusts Total (Dollars in millions) Single-family allowance for loan losses: Beginning balance $ 29,624 $ 1,252 $ 30,876 $ 36,400 $ 2,243 $ 38,643 Provision (benefit) for loan losses (1) (1,722 ) 330 (1,392 ) (1,393 ) 394 (999 ) Charge-offs (2) (748 ) (22 ) (770 ) (1,439 ) (108 ) (1,547 ) Recoveries 161 3 164 271 4 275 Transfers (3) 262 (262 ) — 366 (366 ) — Other (4) (13 ) — (13 ) 170 28 198 Ending balance $ 27,564 $ 1,301 $ 28,865 $ 34,375 $ 2,195 $ 36,570 Multifamily allowance for loan losses: Beginning balance $ 100 $ 174 $ 274 $ 243 $ 181 $ 424 Provision (benefit) for loan losses (1) (10 ) 8 (2 ) (46 ) (6 ) (52 ) Charge-offs (2) (5 ) (2 ) (7 ) (14 ) — (14 ) Recoveries 4 — 4 — — — Transfers (3) 1 (1 ) — 2 (2 ) — Other (4) 1 — 1 2 1 3 Ending balance $ 91 $ 179 $ 270 $ 187 $ 174 $ 361 Total allowance for loan losses: Beginning balance $ 29,724 $ 1,426 $ 31,150 $ 36,643 $ 2,424 $ 39,067 Provision (benefit) for loan losses (1) (1,732 ) 338 (1,394 ) (1,439 ) 388 (1,051 ) Charge-offs (2) (753 ) (24 ) (777 ) (1,453 ) (108 ) (1,561 ) Recoveries 165 3 168 271 4 275 Transfers (3) 263 (263 ) — 368 (368 ) — Other (4) (12 ) — (12 ) 172 29 201 Ending balance $ 27,655 $ 1,480 $ 29,135 $ 34,562 $ 2,369 $ 36,931 For the Nine Months Ended September 30, 2015 2014 Of Fannie Mae Of Consolidated Trusts Total Of Fannie Mae Of Consolidated Trusts Total (Dollars in millions) Single-family allowance for loan losses: Beginning balance $ 32,956 $ 2,221 $ 35,177 $ 40,202 $ 3,105 $ 43,307 Provision (benefit) for loan losses (1) (249 ) (44 ) (293 ) (3,563 ) 192 (3,371 ) Charge-offs (2)(5) (8,108 ) (64 ) (8,172 ) (4,747 ) (251 ) (4,998 ) Recoveries 1,032 15 1,047 902 222 1,124 Transfers (3) 877 (877 ) — 1,123 (1,123 ) — Other (4) 1,056 50 1,106 458 50 508 Ending balance $ 27,564 $ 1,301 $ 28,865 $ 34,375 $ 2,195 $ 36,570 Multifamily allowance for loan losses: Beginning balance $ 161 $ 203 $ 364 $ 319 $ 220 $ 539 Benefit for loan losses (1) (41 ) (23 ) (64 ) (66 ) (44 ) (110 ) Charge-offs (2)(5) (39 ) (2 ) (41 ) (73 ) — (73 ) Recoveries 4 — 4 — — — Transfers (3) 1 (1 ) — 4 (4 ) — Other (4) 5 2 7 3 2 5 Ending balance $ 91 $ 179 $ 270 $ 187 $ 174 $ 361 Total allowance for loan losses: Beginning balance $ 33,117 $ 2,424 $ 35,541 $ 40,521 $ 3,325 $ 43,846 Provision (benefit) for loan losses (1) (290 ) (67 ) (357 ) (3,629 ) 148 (3,481 ) Charge-offs (2)(5) (8,147 ) (66 ) (8,213 ) (4,820 ) (251 ) (5,071 ) Recoveries 1,036 15 1,051 902 222 1,124 Transfers (3) 878 (878 ) — 1,127 (1,127 ) — Other (4) 1,061 52 1,113 461 52 513 Ending balance $ 27,655 $ 1,480 $ 29,135 $ 34,562 $ 2,369 $ 36,931 __________ (1) Provision (benefit) for loan losses is included in “Benefit for credit losses” in our condensed consolidated statements of operations and comprehensive income. (2) While we purchase the substantial majority of loans that are four or more months delinquent from our MBS trusts, we do not exercise this option to purchase loans during a forbearance period. Charge-offs of consolidated trusts generally represent loans that remained in our consolidated trusts at the time of default. (3) Includes transfers from trusts for delinquent loan purchases. (4) Amounts represent changes in other loss reserves which are offset by amounts reflected in provision (benefit) for credit losses, charge-offs and recoveries. (5) Includes for the nine months ended September 30, 2015 charge-offs of (1) $1.8 billion in HFI loans and $ 724 million in preforeclosure property taxes and insurance receivable in connection with our adoption of the Advisory Bulletin on January 1, 2015 and (2) $ 1.1 billion in accrued interest receivable that were charged-off in connection with the our adoption of a change in accounting principle on January 1, 2015 related to the treatment of interest previously accrued, but not collected, at the date that loans are placed on nonaccrual status. The following table displays the allowance for loan losses and total recorded investment in our HFI loans, excluding loans for which we have elected the fair value option, by impairment or reserve methodology and portfolio segment. As of September 30, 2015 December 31, 2014 Single-Family Multifamily Total Single-Family Multifamily Total (Dollars in millions) Allowance for loan losses by segment: Individually impaired loans (1) $ 26,404 $ 113 $ 26,517 $ 31,200 $ 175 $ 31,375 Collectively reserved loans 2,461 157 2,618 3,977 189 4,166 Total allowance for loan losses $ 28,865 $ 270 $ 29,135 $ 35,177 $ 364 $ 35,541 Recorded investment in loans by segment: Individually impaired loans (1) $ 175,479 $ 1,159 $ 176,638 $ 186,377 $ 1,809 $ 188,186 Collectively reserved loans 2,665,062 197,540 2,862,602 2,672,184 187,424 2,859,608 Total recorded investment in loans $ 2,840,541 $ 198,699 $ 3,039,240 $ 2,858,561 $ 189,233 $ 3,047,794 __________ (1) Includes acquired credit-impaired loans.

Investments in Securities

Investments in Securities	9 Months Ended
	Sep. 30, 2015
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 gains (losses), net” in our condensed consolidated statements of operations and comprehensive income. The following table displays our investments in trading securities. As of September 30, 2015 December 31, 2014 (Dollars in millions) Mortgage-related securities: Fannie Mae $ 5,097 $ 4,940 Freddie Mac 1,474 1,369 Ginnie Mae 353 166 Alt-A private-label securities 451 920 Subprime private-label securities 696 1,307 CMBS 2,398 2,515 Mortgage revenue bonds 579 722 Other mortgage-related securities — 99 Total mortgage-related securities 11,048 12,038 U.S. Treasury securities 26,961 19,466 Total trading securities $ 38,009 $ 31,504 The following table displays information about our net trading gains and losses. For the Three For the Nine Months Ended Months Ended September 30, September 30, 2015 2014 2015 2014 (Dollars in millions) Net trading gains $ 13 $ 50 $ 69 $ 444 Net trading gains (losses) recognized in the period related to securities still held at period end (15 ) 56 (29 ) 409 Available-for-Sale Securities We measure 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 Nine Months Ended Months Ended September 30, September 30, 2015 2014 2015 2014 (Dollars in millions) Gross realized gains $ 94 $ 96 $ 907 $ 495 Gross realized losses 9 4 66 5 Total proceeds (1) 1,556 722 6,764 2,461 __________ (1) Excludes proceeds from the initial sale of securities from new portfolio securitizations. The following tables display the amortized cost, gross unrealized gains and losses, and fair value by major security type for AFS securities. As of September 30, 2015 Total Amortized Cost (1) Gross Unrealized Gains Gross Unrealized Losses - OTTI (2) Gross Unrealized Losses - Other (3) Total Fair Value (Dollars in millions) Fannie Mae $ 4,026 $ 275 $ — $ (19 ) $ 4,282 Freddie Mac 4,252 347 — — 4,599 Ginnie Mae 361 52 — — 413 Alt-A private-label securities 2,626 727 (4 ) — 3,349 Subprime private-label securities 2,817 865 — (5 ) 3,677 CMBS 1,273 36 — — 1,309 Mortgage revenue bonds 2,824 129 (17 ) (3 ) 2,933 Other mortgage-related securities 1,408 40 (3 ) — 1,445 Total $ 19,587 $ 2,471 $ (24 ) $ (27 ) $ 22,007 As of December 31, 2014 Total Amortized Cost (1) Gross Unrealized Gains Gross Unrealized Losses - OTTI (2) Gross Unrealized Losses - Other (3) Total Fair Value (Dollars in millions) Fannie Mae $ 5,330 $ 328 $ — $ (19 ) $ 5,639 Freddie Mac 5,100 428 — — 5,528 Ginnie Mae 416 60 — — 476 Alt-A private-label securities 4,638 1,055 (15 ) — 5,678 Subprime private-label securities 4,103 1,161 (9 ) (15 ) 5,240 CMBS 1,341 56 — — 1,397 Mortgage revenue bonds 3,859 177 (8 ) (5 ) 4,023 Other mortgage-related securities 2,626 183 (23 ) (113 ) 2,673 Total $ 27,413 $ 3,448 $ (55 ) $ (152 ) $ 30,654 __________ (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 noncredit component of OTTI losses recorded in “Accumulated other comprehensive income” in our condensed consolidated balance sheets, as well as cumulative changes in fair value of securities for which we previously recognized the credit component of OTTI. (3) Represents the gross unrealized losses on securities for which we have not recognized OTTI. 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 September 30, 2015 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 $ (3 ) $ 116 $ (16 ) $ 511 Alt-A private-label securities (1 ) 132 (3 ) 28 Subprime private-label securities — 38 (5 ) 96 Mortgage revenue bonds (16 ) 584 (4 ) 20 Other mortgage-related securities (3 ) 255 — — Total $ (23 ) $ 1,125 $ (28 ) $ 655 As of December 31, 2014 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 $ — $ 113 $ (19 ) $ 627 Alt-A private-label securities (2 ) 171 (13 ) 112 Subprime private-label securities — — (24 ) 460 Mortgage revenue bonds (2 ) 47 (11 ) 155 Other mortgage-related securities — 8 (136 ) 1,021 Total $ (4 ) $ 339 $ (203 ) $ 2,375 Other-Than-Temporary Impairments We recognized $5 million and $6 million of OTTI for the three months ended September 30, 2015 and 2014 , respectively, and $187 million and $80 million of OTTI for the nine months ended September 30, 2015 and 2014 , respectively, which are included in “Investment gains, net” in our condensed consolidated statements of operations and comprehensive income. During the nine months ended September 30, 2015 , OTTI was primarily driven by a change in our intent to sell certain securities. As a result, we recognized the entire difference between the amortized cost basis of these securities and their fair value as OTTI. The following table displays the modeled attributes, including default rates and severities, which were used to determine as of September 30, 2015 whether our senior interests in certain non-agency mortgage-related securities (including those we intend to sell) will experience a cash shortfall. An estimate of voluntary prepayment rates is also an input to the present value of expected losses. As of September 30, 2015 Alt-A Subprime Option ARM Fixed Rate Variable Rate Hybrid Rate (Dollars in millions) Total unpaid principal balance $ 4,917 $ 494 $ 1,205 $ 838 $ 1,237 Weighted average collateral default (1) 42.4 % 29.4 % 11.9 % 21.4 % 10.0 % Weighted average collateral severities (2) 60.0 38.5 46.9 37.9 34.2 Weighted average voluntary prepayment rates (3) 2.7 7.4 12.2 8.4 12.0 Average credit enhancement (4) 17.4 3.6 5.6 8.6 4.4 __________ (1) The expected remaining cumulative default rate of the collateral pool backing the securities, as a percentage of the current collateral unpaid principal balance, weighted by security unpaid principal balance. (2) The expected remaining loss given default of the collateral pool backing the securities, calculated as the ratio of remaining cumulative loss divided by cumulative defaults, weighted by security unpaid principal balance. (3) The average monthly voluntary prepayment rate, weighted by security unpaid principal balance. (4) The average percent current credit enhancement provided by subordination of other securities. Excludes excess interest projections and monoline bond insurance. The following table displays activity related to the unrealized credit loss component on debt securities held by us and recognized in our condensed consolidated statements of operations and comprehensive income. For the Three Months Ended September 30, For the Nine Months Ended September 30, 2015 2014 2015 2014 (Dollars in millions) Balance, beginning of period $ 2,557 $ 5,871 $ 5,260 $ 7,904 Additions for the credit component on debt securities for which OTTI was not previously recognized — — — 1 Additions for the credit component on debt securities for which OTTI was previously recognized 1 3 5 50 Reductions for securities no longer in portfolio at period end (2 ) (355 ) (1,167 ) (792 ) Reductions for securities which we intend to sell or it is more likely than not that we will be required to sell before recovery of amortized cost basis — — (1,439 ) (1,453 ) Reductions for amortization resulting from changes in cash flows expected to be collected over the remaining life of the securities (43 ) (73 ) (146 ) (264 ) Balance, end of period $ 2,513 $ 5,446 $ 2,513 $ 5,446 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 September 30, 2015 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 $ 4,026 $ 4,282 $ — $ — $ 189 $ 194 $ 165 $ 178 $ 3,672 $ 3,910 Freddie Mac 4,252 4,599 1 1 221 231 332 363 3,698 4,004 Ginnie Mae 361 413 — — 1 1 57 64 303 348 Alt-A private-label securities 2,626 3,349 — — — — — — 2,626 3,349 Subprime private-label securities 2,817 3,677 — — — — — — 2,817 3,677 CMBS 1,273 1,309 171 173 1,037 1,071 — — 65 65 Mortgage revenue bonds 2,824 2,933 11 11 106 108 219 221 2,488 2,593 Other mortgage-related securities 1,408 1,445 — — — — 31 33 1,377 1,412 Total $ 19,587 $ 22,007 $ 183 $ 185 $ 1,554 $ 1,605 $ 804 $ 859 $ 17,046 $ 19,358

Financial Guarantees

Financial Guarantees	9 Months Ended
	Sep. 30, 2015
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 37 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 September 30, 2015 December 31, 2014 Maximum Exposure (1) Guaranty Obligation Maximum Recovery (2) Maximum Exposure (1) Guaranty Obligation Maximum Recovery (2) (Dollars in millions) Unconsolidated Fannie Mae MBS $ 15,556 $ 198 $ 9,077 $ 17,184 $ 214 $ 9,775 Other guaranty arrangements (3) 16,783 140 2,971 18,781 168 4,447 Total $ 32,339 $ 338 $ 12,048 $ 35,965 $ 382 $ 14,222 __________ (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, see “ Note 13, Concentrations of Credit Risk .” (3) Primarily consists of credit enhancements, long-term standby commitments, and our commitment under the TCLF program. 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 $729 million and $797 million as of September 30, 2015 and December 31, 2014 , respectively. These Fannie Mae MBS consist primarily of private-label wraps where our guaranty arrangement is with an unconsolidated MBS trust.

Acquired Property Net

Acquired Property Net	9 Months Ended
	Sep. 30, 2015
Real Estate [Abstract]
Acquired Property, Net	Acquired Property, Net Acquired property, net consists of held-for-sale foreclosed property received in satisfaction of a loan, net of a valuation allowance for declines in the fair value of the properties after initial acquisition. We classify properties as held for sale when we intend to sell the property and are actively marketing it for sale. The following table displays the activity in acquired property, and the related valuation allowance. For the Three Months Ended September 30, For the Nine Months Ended September 30, 2015 2014 2015 2014 (Dollars in millions) Beginning balance — Acquired property $ 9,199 $ 12,296 $ 11,442 $ 12,307 Additions 2,236 3,240 7,602 10,437 Disposals (3,125 ) (3,412 ) (10,734 ) (10,620 ) Ending balance — Acquired property 8,310 12,124 8,310 12,124 Beginning balance — Valuation allowance (693 ) (736 ) (824 ) (686 ) Decrease (increase) in valuation allowance 74 (49 ) 205 (99 ) Ending balance — Valuation allowance (619 ) (785 ) (619 ) (785 ) Ending balance — Acquired property, net $ 7,691 $ 11,339 $ 7,691 $ 11,339

Short-Term Borrowings and Long-

Short-Term Borrowings and Long-Term Debt	9 Months Ended
	Sep. 30, 2015
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 September 30, 2015 December 31, 2014 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) $ 118 — % $ 50 — % Short-term debt of Fannie Mae $ 95,427 0.21 % $ 105,012 0.11 % Debt of consolidated trusts 1,391 0.15 1,560 0.09 Total short-term debt $ 96,818 0.20 % $ 106,572 0.11 % __________ (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 periodically 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 September 30, 2015 and December 31, 2014 . We had no borrowings outstanding from this line of credit as of September 30, 2015 . 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 September 30, 2015 December 31, 2014 Maturities Outstanding Weighted- Average Interest Rate (1) Maturities Outstanding Weighted- Average Interest Rate (1) (Dollars in millions) Senior fixed: Benchmark notes and bonds 2015 - 2030 $ 159,550 2.51 % 2015 - 2030 $ 173,010 2.41 % Medium-term notes (2) 2015 - 2025 100,682 1.49 2015 - 2024 114,556 1.42 Foreign exchange bonds 2021 - 2028 570 5.39 2021 - 2028 619 5.44 Other 2015 - 2038 27,797 4.83 2015 - 2038 32,322 4.63 Total senior fixed 288,599 2.39 320,507 2.29 Senior floating: Medium-term notes (2) 2015 - 2019 19,164 0.22 2015 - 2019 24,469 0.15 Connecticut Avenue Securities (3) 2023 - 2025 9,607 3.39 2023 - 2024 6,041 2.97 Other (4) 2020 - 2037 369 8.25 2020 - 2037 363 8.71 Total senior floating 29,140 1.36 30,873 0.81 Subordinated debentures 2019 4,129 9.93 2019 3,849 9.93 Secured borrowings (5) 2021 - 2022 163 1.35 2021 - 2022 202 1.90 Total long-term debt of Fannie Mae (6) 322,031 2.39 355,431 2.24 Debt of consolidated trusts (4) 2015 - 2054 2,787,396 2.91 2015 - 2054 2,760,152 3.02 Total long-term debt $ 3,109,427 2.85 % $ 3,115,583 2.93 % __________ (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) Credit risk-sharing securities that transfer a portion of the credit risk on specified pools of mortgage loans to the investors in these securities. Connecticut Avenue Securities are reported at fair value. (4) Includes structured debt instruments that are reported at fair value. (5) 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. (6) Includes unamortized discounts and premiums, other cost basis adjustments and fair value adjustments of $3.4 billion and $4.1 billion as of September 30, 2015 and December 31, 2014 , respectively.

Derivative Instruments

Derivative Instruments	9 Months Ended
	Sep. 30, 2015
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 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 15 , 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 September 30, 2015 As of December 31, 2014 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 $ 7,557 $ 42 $ 151,810 $ (9,251 ) $ 41,965 $ 733 $ 123,557 $ (7,125 ) Receive-fixed 157,472 4,434 44,981 (145 ) 67,629 4,486 157,272 (1,302 ) Basis 764 148 10,600 (2 ) 5,769 123 7,100 (2 ) Foreign currency 302 116 265 (46 ) 344 144 273 (30 ) Swaptions: Pay-fixed 6,300 43 13,950 (24 ) 11,100 57 26,525 (175 ) Receive-fixed — — 14,200 (283 ) 750 96 29,525 (816 ) Other (1) 3,956 25 1,993 (1 ) 1,071 28 12 (1 ) Total gross risk management derivatives 176,351 4,808 237,799 (9,752 ) 128,628 5,667 344,264 (9,451 ) Accrued interest receivable (payable) — 835 — (1,220 ) — 749 — (1,013 ) Netting adjustment (2) — (4,417 ) — 10,635 — (5,186 ) — 10,194 Total net risk management derivatives $ 176,351 $ 1,226 $ 237,799 $ (337 ) $ 128,628 $ 1,230 $ 344,264 $ (270 ) Mortgage commitment derivatives: Mortgage commitments to purchase whole loans $ 9,595 $ 57 $ 28 $ — $ 6,157 $ 28 $ 428 $ — Forward contracts to purchase mortgage-related securities 57,746 326 2,245 (4 ) 43,533 223 6,112 (8 ) Forward contracts to sell mortgage-related securities 1,623 1 87,416 (563 ) 4,886 4 57,910 (336 ) Total mortgage commitment derivatives $ 68,964 $ 384 $ 89,689 $ (567 ) $ 54,576 $ 255 $ 64,450 $ (344 ) Derivatives at fair value $ 245,315 $ 1,610 $ 327,488 $ (904 ) $ 183,204 $ 1,485 $ 408,714 $ (614 ) __________ (1) Includes futures and swap credit enhancements, as well as credit risk transfer transactions 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 $6.5 billion and $5.3 billion as of September 30, 2015 and December 31, 2014 , respectively. Cash collateral received was $256 million and $245 million as of September 30, 2015 and December 31, 2014 , respectively. A majority of our OTC derivative contracts contain provisions that require our senior unsecured debt to maintain a minimum credit rating from S&P and Moody’s. If our senior unsecured debt credit ratings were downgraded to established thresholds in these derivative contracts, which range from A+ to BBB+, we could be required to provide additional collateral to or terminate transactions with certain counterparties. The aggregate fair value of all OTC derivatives with credit-risk-related contingent features that were in a net liability position was $3.2 billion and $2.6 billion as of September 30, 2015 and December 31, 2014 , respectively, for which we posted collateral of $2.8 billion and $2.4 billion in the normal course of business as of September 30, 2015 and December 31, 2014 , respectively. Had all of the credit-risk-related contingency features underlying these agreements been triggered, an additional $303 million and $269 million would have been required to be posted as collateral or to immediately settle our positions based on the individual agreements and our fair value position as of September 30, 2015 and December 31, 2014 , respectively. A reduction in our credit ratings may also cause derivatives clearing organizations or their members to demand that we post additional collateral for our cleared derivative contracts. 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 Ended For the Nine Months Ended Ended September 30, Ended September 30, 2015 2014 2015 2014 (Dollars in millions) Risk management derivatives: Swaps: Pay-fixed $ (4,402 ) $ 712 $ (3,120 ) $ (3,755 ) Receive-fixed 2,295 (822 ) 2,236 2,282 Basis 37 6 25 49 Foreign currency (20 ) (17 ) (33 ) 21 Swaptions: Pay-fixed 32 (53 ) 137 (90 ) Receive-fixed (102 ) 82 (181 ) (19 ) Other 22 (1 ) 20 (1 ) Accrual of periodic settlements: Pay-fixed interest-rate swaps (895 ) (939 ) (2,730 ) (2,755 ) Receive-fixed interest-rate swaps 620 613 2,007 1,946 Other 9 12 29 39 Total risk management derivatives fair value losses, net $ (2,404 ) $ (407 ) $ (1,610 ) $ (2,283 ) Mortgage commitment derivatives fair value losses, net (361 ) (73 ) (427 ) (728 ) Total derivatives fair value losses, net $ (2,765 ) $ (480 ) $ (2,037 ) $ (3,011 ) 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 14 , Netting Arrangements ” for information on our rights to offset assets and liabilities.

Earnings (Loss) Per Share

Earnings (Loss) Per Share	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Earnings (Loss) Per Share	Earnings (Loss) 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 (loss) per share of common stock. For the Three Months Ended September 30, For the Nine Months Ended September 30, 2015 2014 2015 2014 (Dollars and shares in millions, except per share amounts) Net income $ 1,960 $ 3,905 $ 8,488 $ 12,897 Less: Net income attributable to noncontrolling interest — — — (1 ) Net income attributable to Fannie Mae 1,960 3,905 8,488 12,896 Dividends distributed or available for distribution to senior preferred stockholder (1) (2,202 ) (3,999 ) (8,357 ) (13,403 ) Net income (loss) attributable to common stockholders $ (242 ) $ (94 ) $ 131 $ (507 ) Weighted-average common shares outstanding—Basic (2) 5,762 5,762 5,762 5,762 Convertible preferred stock — — 131 — Weighted-average common shares outstanding—Diluted (2) 5,762 5,762 5,893 5,762 Earnings (loss) per share: Basic $ (0.04 ) $ (0.02 ) $ 0.02 $ (0.09 ) Diluted (0.04 ) (0.02 ) 0.02 (0.09 ) __________ (1) Dividends distributed or available for distribution for the three months ended September 30, 2015 and 2014 (relating to the dividend periods for the three months ended December 31, 2015 and 2014) were calculated based on our net worth as of September 30, 2015 and 2014, respectively, less the applicable capital reserve. For the nine months ended September 30, 2015 , we add dividends paid related to the dividend periods for the three months ended September 30, 2015 and June 30, 2015. For the nine months ended September 30, 2014 , we add dividends paid related to the dividend periods for the three months ended September 30, 2014 and June 30, 2014. (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 September 30, 2015 and 2014.

Segment Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting Our three reportable segments are: Single-Family, Multifamily and Capital Markets. We use these three segments to generate revenue and manage business risk, and each segment is based on the type of business activities it performs. Under our segment reporting, the sum of the results for our three business segments does not equal our condensed consolidated statements of operations and comprehensive income, as we separate the activity related to our consolidated trusts from the results generated by our three segments. Our business segment financial results include directly attributable revenues and expenses. Additionally, we allocate to each of our segments: (1) capital using FHFA minimum capital requirements adjusted for over- or under-capitalization; (2) indirect administrative costs; and (3) a provision or benefit for federal income taxes. In addition, we allocate intracompany guaranty fee income as a charge from the Single-Family and Multifamily segments to Capital Markets for managing the credit risk on mortgage loans held by the Capital Markets group. We also include an eliminations/adjustments category to reconcile our business segment financial results and the activity related to our consolidated trusts to net income in our condensed consolidated statements of operations and comprehensive income. For the Three Months Ended September 30, 2015 Business Segments Other Activity/Reconciling Items Single-Family Multifamily Capital Markets Consolidated Trusts (1) Eliminations/ Adjustments (2) Total Results (Dollars in millions) Net interest income (loss) $ 66 $ (16 ) $ 1,401 $ 3,901 $ 236 (3) $ 5,588 Benefit for credit losses 1,545 5 — — — 1,550 Net interest income (loss) after benefit for credit losses 1,611 (11 ) 1,401 3,901 236 7,138 Guaranty fee income (expense) (4) 3,145 367 (210 ) (2,024 ) (5) (1,247 ) (5) 31 (5) Investment gains (losses), net (1 ) 5 1,608 (187 ) (1,126 ) (6) 299 Fair value gains (losses), net (4 ) — (2,697 ) 32 80 (7) (2,589 ) Debt extinguishment gains (losses), net — — (25 ) 14 — (11 ) Gains (losses) from partnership investments (8) (12 ) 7 — — — (5 ) Fee and other income (expense) 98 58 83 (80 ) 69 228 Administrative expenses (649 ) (109 ) (194 ) — — (952 ) Foreclosed property income (expense) (516 ) 19 — — — (497 ) TCCA fees (4) (413 ) — — — — (413 ) Other income (expenses) (180 ) 5 24 (93 ) 45 (199 ) Income (loss) before federal income taxes 3,079 341 (10 ) 1,563 (1,943 ) 3,030 Provision for federal income taxes (1,040 ) (17 ) (13 ) — — (1,070 ) Net income (loss) attributable to Fannie Mae $ 2,039 $ 324 $ (23 ) $ 1,563 $ (1,943 ) $ 1,960 For the Nine Months Ended September 30, 2015 Business Segments Other Activity/Reconciling Items Single-Family Multifamily Capital Markets Consolidated Trusts (1) Eliminations/ Adjustments (2) Total Results (Dollars in millions) Net interest income (loss) $ 93 $ (73 ) $ 4,516 $ 11,039 $ 757 (3) $ 16,332 Benefit for credit losses 967 83 — — — 1,050 Net interest income after benefit for credit losses 1,060 10 4,516 11,039 757 17,382 Guaranty fee income (expense) (4) 9,277 1,064 (658 ) (5,929 ) (5) (3,655 ) (5) 99 (5) Investment gains (losses), net (2 ) 29 4,679 (664 ) (2,887 ) (6) 1,155 Fair value gains (losses), net (8 ) — (2,112 ) 37 181 (7) (1,902 ) Debt extinguishment gains (losses), net — — (30 ) 30 — — Gains (losses) from partnership investments (8) (27 ) 262 — — — 235 Fee and other income (expense) 571 193 288 (249 ) 221 1,024 Administrative expenses (1,591 ) (280 ) (493 ) — — (2,364 ) Foreclosed property income (expense) (1,183 ) 31 — — — (1,152 ) TCCA fees (4) (1,192 ) — — — — (1,192 ) Other income (expenses) (669 ) (8 ) 18 (93 ) 105 (647 ) Income before federal income taxes 6,236 1,301 6,208 4,171 (5,278 ) 12,638 Provision for federal income taxes (2,040 ) (128 ) (1,982 ) — — (4,150 ) Net income attributable to Fannie Mae $ 4,196 $ 1,173 $ 4,226 $ 4,171 $ (5,278 ) $ 8,488 For the Three Months Ended September 30, 2014 Business Segments Other Activity/Reconciling Items Single-Family Multifamily Capital Markets Consolidated Trusts (1) Eliminations/ Adjustments (2) Total Results (Dollars in millions) Net interest income (loss) $ 19 $ (22 ) $ 1,845 $ 3,088 $ 254 (3) $ 5,184 Benefit for credit losses 1,029 56 — — — 1,085 Net interest income after benefit for credit losses 1,048 34 1,845 3,088 254 6,269 Guaranty fee income (expense) (4) 2,945 332 (235 ) (1,488 ) (5) (1,502 ) (5) 52 (5) Investment gains, net — 8 1,510 21 (1,368 ) (6) 171 Fair value gains (losses), net (4 ) — (335 ) 13 119 (7) (207 ) Debt extinguishment gains (losses), net — — (3 ) 14 — 11 Gains from partnership investments (8) — 52 — — — 52 Fee and other income (expense) 146 32 579 (71 ) 88 774 Administrative expenses (468 ) (77 ) (161 ) — — (706 ) Foreclosed property income (expense) (281 ) 32 — — — (249 ) TCCA fees (4) (351 ) — — — — (351 ) Other income (expenses) (136 ) 8 (5 ) — 9 (124 ) Income before federal income taxes 2,899 421 3,195 1,577 (2,400 ) 5,692 Provision for federal income taxes (837 ) (37 ) (913 ) — — (1,787 ) Net income attributable to Fannie Mae $ 2,062 $ 384 $ 2,282 $ 1,577 $ (2,400 ) $ 3,905 For the Nine Months Ended September 30, 2014 Business Segments Other Activity/Reconciling Items Single-Family Multifamily Capital Markets Consolidated Trusts (1) Eliminations/ Adjustments (2) Total Results (Dollars in millions) Net interest income (loss) $ (24 ) $ (65 ) $ 5,592 $ 8,525 $ 798 (3) $ 14,826 Benefit for credit losses 3,377 121 — — — 3,498 Net interest income after benefit for credit losses 3,353 56 5,592 8,525 798 18,324 Guaranty fee income (expense) (4) 8,708 960 (722 ) (4,367 ) (5) (4,441 ) (5) 138 (5) Investment gains (losses), net (1 ) 50 4,420 (141 ) (3,579 ) (6) 749 Fair value gains (losses), net (11 ) — (2,770 ) 232 218 (7) (2,331 ) Debt extinguishment gains, net — — 31 18 — 49 Gains from partnership investments (8) — 131 — — 1 132 Fee and other income (expense) 471 87 4,848 (242 ) 262 5,426 Administrative expenses (1,376 ) (225 ) (474 ) — — (2,075 ) Foreclosed property income 154 73 — — — 227 TCCA fees (4) (1,008 ) — — — — (1,008 ) Other expenses (528 ) (5 ) (70 ) — (8 ) (611 ) Income before federal income taxes 9,762 1,127 10,855 4,025 (6,749 ) 19,020 Provision for federal income taxes (2,897 ) (37 ) (3,189 ) — — (6,123 ) Net income 6,865 1,090 7,666 4,025 (6,749 ) 12,897 Less: Net income attributable to noncontrolling interest — — — — (1 ) (1 ) Net income attributable to Fannie Mae $ 6,865 $ 1,090 $ 7,666 $ 4,025 $ (6,750 ) $ 12,896 __________ (1) Represents activity related to the assets and liabilities of consolidated trusts in our condensed consolidated balance sheets. (2) Represents the elimination of intercompany transactions occurring between the three business segments and our consolidated trusts, as well as other adjustments to reconcile to our consolidated results. (3) Represents the amortization expense of cost basis adjustments on securities in the Capital Markets group’s retained mortgage portfolio that on a GAAP basis are eliminated. (4) Reflects the impact of a 10 basis point guaranty fee increase implemented pursuant to the TCCA, the incremental revenue from which must be remitted to Treasury. The resulting revenue is included in guaranty fee income and the expense is recognized as “TCCA fees.” (5) Represents the guaranty fees paid from consolidated trusts to the Single-Family and Multifamily segments. The adjustment to guaranty fee income in the Eliminations/Adjustments column represents the elimination of the amortization of deferred cash fees related to consolidated trusts that were re-established for segment reporting. Total guaranty fee income related to unconsolidated Fannie Mae MBS trusts and other credit enhancement arrangements is included in fee and other income in our condensed consolidated statements of operations and comprehensive income. (6) Primarily represents the removal of realized gains and losses on sales of Fannie Mae MBS classified as available-for-sale securities that are issued by consolidated trusts and in the Capital Markets group’s retained mortgage portfolio. The adjustment also includes the removal of securitization gains (losses) recognized in the Capital Markets segment relating to portfolio securitization transactions that do not qualify for sale accounting under GAAP. (7) Represents the removal of fair value adjustments on consolidated Fannie Mae MBS classified as trading that are in the Capital Markets group’s retained mortgage portfolio. (8) Gains (losses) from partnership investments are included in other expenses in our condensed consolidated statements of operations and comprehensive income.

Equity

Equity	9 Months Ended
	Sep. 30, 2015
Equity [Abstract]
Equity	Equity The following table displays the activity in other comprehensive income (“OCI”), net of tax, by major categories. For the Three Months Ended September 30, For the Nine Months Ended September 30, 2015 2014 2015 2014 (Dollars in millions) Net income $ 1,960 $ 3,905 $ 8,488 $ 12,897 Other comprehensive income (loss), net of tax effect: Changes in net unrealized gains on AFS securities (net of tax of $58 and $61, respectively, for the three months ended and net of tax of $89 and $364, respectively, for the nine months ended) (107 ) 113 (164 ) 675 Reclassification adjustment for OTTI recognized in net income (net of tax of $2 for the three months ended and net of tax of $66 and $28, respectively, for the nine months ended) 3 4 121 52 Reclassification adjustment for gains on AFS securities included in net income (net of tax of $32 and $29, respectively, for the three months ended and net of tax of $265 and $133, respectively for the nine months ended) (73 ) (54 ) (505 ) (247 ) Other (1) 430 32 428 32 Total other comprehensive income (loss) 253 95 (120 ) 512 Total comprehensive income $ 2,213 $ 4,000 $ 8,368 $ 13,409 __________ (1) For the three and nine months ended September 30, 2015, includes reclassification adjustment related to the termination of the defined benefit pension plan recognized in “Administrative expenses” and “Provision for federal income taxes” in our condensed consolidated statements of operations and comprehensive income. The following table displays our accumulated other comprehensive income (“AOCI”) by major categories. As of September 30, December 31, 2015 2014 (Dollars in millions) Net unrealized gains on AFS securities for which we have not recorded OTTI, net of tax $ 551 $ 592 Net unrealized gains on AFS securities for which we have recorded OTTI, net of tax 1,022 1,529 Prior service credit (cost) and actuarial gains (losses), net of amortization, net of tax 39 (358 ) Other gains (losses) 1 (30 ) Accumulated other comprehensive income $ 1,613 $ 1,733 The table below displays changes in AOCI, net of tax. For the Three Months Ended September 30, For the Nine Months Ended September 30, 2015 2014 2015 2014 AFS (1) Other (2) Total AFS (1) Other Total AFS (1) Other (2) Total AFS (1) Other Total (Dollars in millions) Beginning balance $ 1,750 $ (390 ) $ 1,360 $ 2,044 $ (424 ) $ 1,620 $ 2,121 $ (388 ) $ 1,733 $ 1,627 $ (424 ) $ 1,203 OCI before reclassifications (107 ) 6 (101 ) 113 32 145 (164 ) 6 (158 ) 675 32 707 Amounts reclassified from OCI (70 ) 424 354 (50 ) — (50 ) (384 ) 422 38 (195 ) — (195 ) Net OCI (177 ) 430 253 63 32 95 (548 ) 428 (120 ) 480 32 512 Ending balance $ 1,573 $ 40 $ 1,613 $ 2,107 $ (392 ) $ 1,715 $ 1,573 $ 40 $ 1,613 $ 2,107 $ (392 ) $ 1,715 __________ (1) The amounts reclassified from AOCI 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 “Investments gains, net” in our condensed consolidated statements of operations and comprehensive income. (2) The amounts reclassified from AOCI represent activity from our defined benefit pension plans, which is recorded in “Administrative expenses” and “Provision for federal income taxes,” in our condensed consolidated statements of operations and comprehensive income.

Concentrations of Credit Risk

Concentrations of Credit Risk	9 Months Ended
	Sep. 30, 2015
Risks and Uncertainties [Abstract]
Concentrations of Credit Risk	Concentrations of Credit Risk Risk Characteristics of our Book of Business We gauge our performance risk under our guaranty based on 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 loan-to-value (“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 and current estimated 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 September 30 , 2015 (1) December 31, 2014 (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) 1.29 % 0.36 % 1.64 % 1.27 % 0.38 % 1.99 % Percentage of single-family conventional loans (4) 1.48 0.40 1.59 1.47 0.43 1.89 As of September 30, 2015 (1) December 31, 2014 (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% 3 % 10.71 % 5 % 10.98 % Geographical distribution: California 20 0.60 20 0.70 Florida 6 3.11 6 4.42 Illinois 4 1.95 4 2.36 New Jersey 4 5.01 4 5.78 New York 5 3.67 5 4.17 All other states 61 1.33 61 1.52 Product distribution: Alt-A 4 6.75 4 7.77 Vintages: 2005 2 5.66 3 6.18 2006 3 8.58 3 9.61 2007 4 9.80 4 10.79 2008 2 5.86 2 6.27 All other vintages 89 0.78 88 0.88 __________ (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 September 30, 2015 and December 31, 2014 . (2) Consists of single-family conventional loans that were 90 days or more past due or in the foreclosure process as of September 30, 2015 and December 31, 2014 . (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 September 30, 2015 (1)(2) December 31, 2014 (1)(2) 30 Days Delinquent Seriously Delinquent (3) 30 Days Delinquent Seriously Delinquent (3) Percentage of multifamily guaranty book of business 0.04 % 0.05 % 0.04 % 0.05 % As of September 30, 2015 (1) December 31, 2014 (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% 3 % 0.03 % 3 % 0.31 % Less than or equal to 80% 97 0.06 97 0.04 Current debt service coverage ratio less than 1.0 (5) 2 0.87 3 0.83 __________ (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 September 30, 2015 and December 31, 2014 , 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 are also obligated to repurchase loans or foreclosed properties, reimburse us for losses or provide other remedies if the foreclosed property has been sold, under certain circumstances, such as if it is determined that the mortgage loan did not meet our underwriting or eligibility requirements, if 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 44% of our single-family guaranty book of business as of September 30, 2015 , compared with 46% as of December 31, 2014 . Our ten largest multifamily mortgage servicers, including their affiliates, serviced approximately 69% of our multifamily guaranty book of business as of September 30, 2015 , compared with approximately 67% as of December 31, 2014 . 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 result in an increase in our credit losses and credit-related expense, and have a material adverse effect on our results of operations, liquidity, financial condition and net worth. 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 $115.7 billion and $109.6 billion on the single-family mortgage loans in our guaranty book of business as of September 30, 2015 and December 31, 2014 , respectively, which represented 4% of our single-family guaranty book of business as of September 30, 2015 and December 31, 2014 . Our primary mortgage insurance coverage risk in force was $114.9 billion and $108.7 billion as of September 30, 2015 and December 31, 2014 , respectively. Our pool mortgage insurance coverage risk in force was $770 million and $852 million as of September 30, 2015 and December 31, 2014 , respectively. Our top four mortgage insurance companies provided 79% of our mortgage insurance as of September 30, 2015 and December 31, 2014 . Of our largest primary mortgage insurers, PMI Mortgage Insurance Co. (“PMI”), Triad Guaranty Insurance Corporation (“Triad”) and Republic Mortgage Insurance Company (“RMIC”) 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 $10.6 billion , or 9% , of our risk in force mortgage insurance coverage of our single-family guaranty book of business as of September 30, 2015 . In April 2015, PMI increased its cash payments on policyholder claims from 67% to 70% , and subsequently paid sufficient amounts of its outstanding deferred payment obligations to bring payment on those claims to 70% . It is uncertain whether PMI will be permitted in the future to pay any remaining deferred policyholder claims or increase or decrease the amount of cash they pay on claims. Although the financial condition of our mortgage insurer counterparties currently approved to write new business has improved in recent years, there is still 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 result in an increase in 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 result in an increase in our loss reserves. As of September 30, 2015 and December 31, 2014 , the amount by which our estimated benefit from mortgage insurance reduced our total loss reserves as of these dates was $2.3 billion and $4.1 billion , respectively. We had outstanding receivables of $1.2 billion recorded in “Other assets” in our condensed consolidated balance sheets as of September 30, 2015 and $1.4 billion as of December 31, 2014 related to amounts claimed on insured, defaulted loans excluding government insured loans. Of this amount, $280 million as of September 30, 2015 and $269 million as of December 31, 2014 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 $795 million as of September 30, 2015 and $799 million as of December 31, 2014 . The valuation allowance reduces our claim receivable to the amount which is considered probable of collection as of September 30, 2015 and December 31, 2014 . For information on credit risk associated with our derivative transactions and repurchase agreements refer to “ Note 9, Derivative Instruments ” and “ Note 14, Netting Arrangements .”

Netting Arrangements

Netting Arrangements	9 Months Ended
	Sep. 30, 2015
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 September 30, 2015 Net Amount Presented in the Condensed Consolidated Balance Sheets Amounts Not Offset in the 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 $ 4,494 $ (4,487 ) $ 7 $ — $ — $ 7 Cleared risk management derivatives 1,124 70 1,194 — — 1,194 Mortgage commitment derivatives 384 — 384 (189 ) (2 ) 193 Total derivative assets 6,002 (4,417 ) 1,585 (4 ) (189 ) (2 ) 1,394 Securities purchased under agreements to resell or similar arrangements (5) 42,100 — 42,100 — (42,100 ) — Total assets $ 48,102 $ (4,417 ) $ 43,685 $ (189 ) $ (42,102 ) $ 1,394 Liabilities: OTC risk management derivatives $ (7,417 ) $ 7,082 $ (335 ) $ — $ — $ (335 ) Cleared risk management derivatives (3,554 ) 3,553 (1 ) — 1 — Mortgage commitment derivatives (567 ) — (567 ) 189 6 (372 ) Total derivative liabilities (11,538 ) 10,635 (903 ) (4 ) 189 7 (707 ) Securities sold under agreements to repurchase or similar arrangements (118 ) — (118 ) — 118 — Total liabilities $ (11,656 ) $ 10,635 $ (1,021 ) $ 189 $ 125 $ (707 ) As of December 31, 2014 Net Amount Presented in the Condensed Consolidated Balance Sheets Amounts Not Offset in the 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 $ 5,461 $ (5,428 ) $ 33 $ — $ (33 ) $ — Cleared risk management derivatives 927 242 1,169 — — 1,169 Mortgage commitment derivatives 255 — 255 (116 ) (7 ) 132 Total derivative assets 6,643 (5,186 ) 1,457 (4 ) (116 ) (40 ) 1,301 Securities purchased under agreements to resell or similar arrangements (5) 47,550 — 47,550 — (47,550 ) — Total assets $ 54,193 $ (5,186 ) $ 49,007 $ (116 ) $ (47,590 ) $ 1,301 Liabilities: OTC risk management derivatives $ (7,836 ) $ 7,567 $ (269 ) $ — $ — $ (269 ) Cleared risk management derivatives (2,627 ) 2,627 — — — — Mortgage commitment derivatives (344 ) — (344 ) 116 — (228 ) Total derivative liabilities (10,807 ) 10,194 (613 ) (4 ) 116 — (497 ) Securities sold under agreements to repurchase or similar arrangements (50 ) — (50 ) — 50 — Total liabilities $ (10,857 ) $ 10,194 $ (663 ) $ 116 $ 50 $ (497 ) __________ (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 collateral received that has neither been recognized nor offset in our condensed consolidated balance sheets as well as collateral posted that has neither been derecognized nor 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 accepted for OTC risk management derivatives was $51 million as of December 31, 2014 . The fair value of non-cash collateral accepted for securities purchased under agreements to resell or similar arrangements was $42.2 billion and $47.6 billion , of which $37.9 billion and $41.9 billion could be sold or repledged as of September 30, 2015 and December 31, 2014 , respectively. None of the underlying collateral was sold or repledged as of September 30, 2015 or December 31, 2014 . The fair value of non-cash collateral we pledged for securities sold under agreements to repurchase was $ 118 million and $50 million as of September 30, 2015 and December 31, 2014 , respectively, which the counterparty was permitted to sell or repledge. The fair value of non-cash collateral we pledged for cleared risk management derivatives was $ 136 million as of September 30, 2015, which the counterparty was permitted to sell or repledge. (4) Excludes derivative assets of $25 million and $28 million as of September 30, 2015 and December 31, 2014 , respectively, and derivative liabilities of $1 million as of September 30, 2015 and December 31, 2014 , recognized in our condensed consolidated balance sheets that are not subject to enforceable master netting arrangements. (5) Includes $15.5 billion and $16.6 billion of securities purchased under agreements to resell or similar arrangements classified as “Cash and cash equivalents” in our condensed consolidated balance sheets as of September 30, 2015 and December 31, 2014 , 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. In addition, 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	9 Months Ended
	Sep. 30, 2015
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 September 30, 2015 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 $ — $ 5,097 $ — $ — $ 5,097 Freddie Mac — 1,474 — — 1,474 Ginnie Mae — 353 — — 353 Alt-A private-label securities — 136 315 — 451 Subprime private-label securities — — 696 — 696 CMBS — 2,398 — — 2,398 Mortgage revenue bonds — — 579 — 579 Non-mortgage-related securities: U.S. Treasury securities 26,961 — — — 26,961 Total trading securities 26,961 9,458 1,590 — 38,009 Available-for-sale securities: Mortgage-related securities: Fannie Mae — 4,282 — — 4,282 Freddie Mac — 4,595 4 — 4,599 Ginnie Mae — 413 — — 413 Alt-A private-label securities — 1,855 1,494 — 3,349 Subprime private-label securities — — 3,677 — 3,677 CMBS — 1,309 — — 1,309 Mortgage revenue bonds — — 2,933 — 2,933 Other — 1 1,444 — 1,445 Total available-for-sale securities — 12,455 9,552 — 22,007 Mortgage loans — 13,105 1,500 — 14,605 Other assets: Risk management derivatives: Swaps — 5,417 158 — 5,575 Swaptions — 39 4 — 43 Other — — 25 — 25 Netting adjustment — — — (4,417 ) (4,417 ) Mortgage commitment derivatives — 374 10 — 384 Total other assets — 5,830 197 (4,417 ) 1,610 Total assets at fair value $ 26,961 $ 40,848 $ 12,839 $ (4,417 ) $ 76,231 Fair Value Measurements as of September 30, 2015 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 $ — $ 9,606 $ 369 $ — $ 9,975 Total of Fannie Mae — 9,606 369 — 9,975 Of consolidated trusts — 22,572 571 — 23,143 Total long-term debt — 32,178 940 — 33,118 Other liabilities: Risk management derivatives: Swaps — 10,531 133 — 10,664 Swaptions — 307 — — 307 Other — — 1 — 1 Netting adjustment — — — (10,635 ) (10,635 ) Mortgage commitment derivatives — 564 3 — 567 Total other liabilities — 11,402 137 (10,635 ) 904 Total liabilities at fair value $ — $ 43,580 $ 1,077 $ (10,635 ) $ 34,022 Fair Value Measurements as of December 31, 2014 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 $ — $ 4,635 $ 305 $ — $ 4,940 Freddie Mac — 1,369 — — 1,369 Ginnie Mae — 166 — — 166 Alt-A private-label securities — 323 597 — 920 Subprime private-label securities — — 1,307 — 1,307 CMBS — 2,515 — — 2,515 Mortgage revenue bonds — — 722 — 722 Other — — 99 — 99 Non-mortgage-related securities: U.S. Treasury securities 19,466 — — — 19,466 Total trading securities 19,466 9,008 3,030 — 31,504 Available-for-sale securities: Mortgage-related securities: Fannie Mae — 5,639 — — 5,639 Freddie Mac — 5,522 6 — 5,528 Ginnie Mae — 476 — — 476 Alt-A private-label securities — 2,538 3,140 — 5,678 Subprime private-label securities — — 5,240 — 5,240 CMBS — 1,397 — — 1,397 Mortgage revenue bonds — — 4,023 — 4,023 Other — 2 2,671 — 2,673 Total available-for-sale securities — 15,574 15,080 — 30,654 Mortgage loans — 13,796 1,833 — 15,629 Other assets: Risk management derivatives: Swaps — 6,085 150 — 6,235 Swaptions — 153 — — 153 Other — — 28 — 28 Netting adjustment — — — (5,186 ) (5,186 ) Mortgage commitment derivatives — 251 4 — 255 Total other assets — 6,489 182 (5,186 ) 1,485 Total assets at fair value $ 19,466 $ 44,867 $ 20,125 $ (5,186 ) $ 79,272 Fair Value Measurements as of December 31, 2014 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 $ — $ 6,040 $ 363 $ — $ 6,403 Total of Fannie Mae — 6,040 363 — 6,403 Of consolidated trusts — 18,956 527 — 19,483 Total long-term debt — 24,996 890 — 25,886 Other liabilities: Risk management derivatives: Swaps — 9,339 133 — 9,472 Swaptions — 991 — — 991 Other — — 1 — 1 Netting adjustment — — — (10,194 ) (10,194 ) Mortgage commitment derivatives — 341 3 — 344 Total other liabilities — 10,671 137 (10,194 ) 614 Total liabilities at fair value $ — $ 35,667 $ 1,027 $ (10,194 ) $ 26,500 __________ (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 both 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 September 30, 2015 Total Gains or (Losses) (Realized/Unrealized) Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of September 30, 2015 (5)(6) Balance, June 30, 2015 Included in Net Income Included in Other Comprehensive Income (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 (4) Transfers into Level 3 (4) Balance, September 30, 2015 (Dollars in millions) Trading securities: Mortgage-related: Alt-A private-label securities $ 325 $ (3 ) $ — $ — $ — $ — $ (7 ) $ — $ — $ 315 $ (3 ) Subprime private-label securities 718 (5 ) — — — — (17 ) — — 696 (5 ) Mortgage revenue bonds 602 (19 ) — — — — (4 ) — — 579 (19 ) Total trading securities $ 1,645 $ (27 ) (6)(7) $ — $ — $ — $ — $ (28 ) $ — $ — $ 1,590 $ (27 ) Available-for-sale securities: Mortgage-related: Fannie Mae $ 129 $ — $ — $ — $ (122 ) $ — $ (8 ) $ — $ 1 $ — $ — Freddie Mac 4 — — — — — — (1 ) 1 4 — Alt-A private-label securities 1,654 2 (8 ) — — — (178 ) — 24 1,494 — Subprime private-label securities 3,837 33 (45 ) — — — (148 ) — — 3,677 — Mortgage revenue bonds 3,171 4 (29 ) — (8 ) — (205 ) — — 2,933 — Other 2,158 73 (95 ) — (644 ) — (48 ) — — 1,444 — Total available-for-sale securities $ 10,953 $ 112 (7)(8) $ (177 ) $ — $ (774 ) $ — $ (587 ) $ (1 ) $ 26 $ 9,552 $ — Mortgage loans $ 1,595 $ 9 (6)(7) $ — $ — $ — $ — $ (97 ) $ (77 ) $ 70 $ 1,500 $ (24 ) Net derivatives 4 79 (6) — — — — (32 ) — 9 60 28 Long-term debt: Of Fannie Mae: Senior floating $ (346 ) $ (23 ) $ — $ — $ — $ — $ — $ — $ — $ (369 ) $ (23 ) Of consolidated trusts (493 ) — — — — (64 ) 18 33 (65 ) (571 ) — Total long-term debt $ (839 ) $ (23 ) (6) $ — $ — $ — $ (64 ) $ 18 $ 33 $ (65 ) $ (940 ) $ (23 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Nine Months Ended September 30, 2015 Total Gains or (Losses) (Realized/Unrealized) Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of September 30, 2015 (5)(6) Balance, December 31, 2014 Included in Net Income Included in Other Comprehensive Income (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 (4) Transfers into Level 3 (4) Balance, September 30, 2015 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 305 $ (27 ) $ — $ — $ (2 ) $ — $ — $ (278 ) $ 2 $ — $ — Alt-A private-label securities 597 41 — — (267 ) — (40 ) (44 ) 28 315 (3 ) Subprime private-label securities 1,307 38 — — (580 ) — (69 ) — — 696 (2 ) Mortgage revenue bonds 722 (17 ) — — (118 ) — (8 ) — — 579 (17 ) Other 99 4 — — (100 ) — (3 ) — — — — Total trading securities $ 3,030 $ 39 (6)(7) $ — $ — $ (1,067 ) $ — $ (120 ) $ (322 ) $ 30 $ 1,590 $ (22 ) Available-for-sale securities: Mortgage-related: Fannie Mae $ — $ — $ — $ 421 $ (425 ) $ — $ (8 ) $ — $ 12 $ — $ — Freddie Mac 6 — — — — — (1 ) (2 ) 1 4 — Alt-A private-label securities 3,140 174 (124 ) — (1,108 ) — (387 ) (538 ) 337 1,494 — Subprime private-label securities 5,240 478 (277 ) — (1,325 ) — (439 ) — — 3,677 — Mortgage revenue bonds 4,023 44 (56 ) — (324 ) — (754 ) — — 2,933 — Other 2,671 (20 ) (10 ) — (1,012 ) — (185 ) — — 1,444 — Total available-for-sale securities $ 15,080 $ 676 (7)(8) $ (467 ) $ 421 $ (4,194 ) $ — $ (1,774 ) $ (540 ) $ 350 $ 9,552 $ — Mortgage loans $ 1,833 $ 47 (6)(7) $ — $ 5 $ — $ — $ (273 ) $ (331 ) $ 219 $ 1,500 $ (17 ) Net derivatives 45 (20 ) (6) — — — — 26 — 9 60 23 Long-term debt: Of Fannie Mae: Senior floating $ (363 ) $ (6 ) $ — $ — $ — $ — $ — $ — $ — $ (369 ) $ (6 ) Of consolidated trusts (527 ) (8 ) — — — (64 ) 43 142 (157 ) (571 ) 11 Total long-term debt $ (890 ) $ (14 ) (6) $ — $ — $ — $ (64 ) $ 43 $ 142 $ (157 ) $ (940 ) $ 5 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Three Months Ended September 30, 2014 Total Gains or (Losses) (Realized/Unrealized) Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of September 30, 2014 (5)(6) Balance, June 30, 2014 Included in Net Income Included in Other Comprehensive Income (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 (4) Transfers into Level 3 (4) Balance, September 30, 2014 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ — $ — $ — $ — $ — $ — $ — $ — $ 325 $ 325 $ — Alt-A private-label securities 643 2 — — — — (21 ) (16 ) 87 695 3 Subprime private-label securities 1,282 66 — — — — (32 ) — — 1,316 66 Mortgage revenue bonds 643 53 — — — — (3 ) — — 693 46 Other 101 1 — — — — (3 ) — — 99 1 Total trading securities $ 2,669 $ 122 (6)(7) $ — $ — $ — $ — $ (59 ) $ (16 ) $ 412 $ 3,128 $ 116 Available-for-sale securities: Mortgage-related: Fannie Mae $ 2 $ — $ — $ — $ — $ — $ — $ (2 ) $ — $ — $ — Freddie Mac 9 — — — — — (1 ) (2 ) — 6 — Alt-A private-label securities 3,717 15 (60 ) — — — (111 ) (333 ) 268 3,496 — Subprime private-label securities 5,705 87 89 — (317 ) — (178 ) — — 5,386 — Mortgage revenue bonds 4,560 (4 ) 200 — (12 ) — (478 ) — — 4,266 — Other 2,817 11 (3 ) — — — (82 ) — — 2,743 — Total available-for-sale securities $ 16,810 $ 109 (7)(8) $ 226 $ — $ (329 ) $ — $ (850 ) $ (337 ) $ 268 $ 15,897 $ — Mortgage loans $ 2,531 $ 116 (6)(7) $ — $ 3 $ — $ — $ (93 ) $ (750 ) $ 64 $ 1,871 $ (13 ) Net derivatives 20 (25 ) (6) — — — — (9 ) — 5 (9 ) 41 (9 ) Long-term debt: Of Fannie Mae: Senior floating $ (325 ) $ (10 ) $ — $ — $ — $ — $ (1 ) $ — $ — $ (336 ) $ (11 ) Of consolidated trusts (498 ) (14 ) — — — — 16 34 (26 ) (488 ) (14 ) Total long-term debt $ (823 ) $ (24 ) (6) $ — $ — $ — $ — $ 15 $ 34 $ (26 ) $ (824 ) $ (25 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Nine Months Ended September 30, 2014 Total Gains or (Losses) (Realized/Unrealized) Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of September 30, 2014 (5)(6) Balance, December 31, 2013 Included in Net Income Included in Other Comprehensive Income (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 (4) Transfers into Level 3 (4) Balance, September 30, 2014 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 42 $ (1 ) $ — $ — $ — $ — $ (2 ) $ (39 ) $ 325 $ 325 $ — Freddie Mac 2 — — — — — — (2 ) — — — Alt-A private-label securities 618 105 — — (23 ) — (59 ) (159 ) 213 695 100 Subprime private-label securities 1,448 245 — — (241 ) — (136 ) — — 1,316 209 Mortgage revenue bonds 565 137 — — — — (9 ) — — 693 130 Other 99 10 — — — — (10 ) — — 99 10 Total trading securities $ 2,774 $ 496 (6)(7) $ — $ — $ (264 ) $ — $ (216 ) $ (200 ) $ 538 $ 3,128 $ 449 Available-for-sale securities: Mortgage-related: Fannie Mae $ 7 $ — $ — $ — $ — $ — $ (1 ) $ (8 ) $ 2 $ — $ — Freddie Mac 8 — — — — — (1 ) (2 ) 1 6 — Alt-A private-label securities 3,791 131 (11 ) — (320 ) — (310 ) (1,207 ) 1,422 3,496 — Subprime private-label securities 7,068 388 270 — (1,666 ) — (674 ) — — 5,386 — Mortgage revenue bonds 5,253 (31 ) 480 — (70 ) — (1,366 ) — — 4,266 — Other 2,885 17 92 — — — (251 ) — — 2,743 — Total available-for-sale securities $ 19,012 $ 505 (7)(8) $ 831 $ — $ (2,056 ) $ — $ (2,603 ) $ (1,217 ) $ 1,425 $ 15,897 $ — Mortgage loans $ 2,704 $ 243 (6)(7) $ — $ 34 $ — $ — $ (259 ) $ (1,063 ) $ 212 $ 1,871 $ 49 Net derivatives (40 ) 52 (6) — — — — (25 ) (1 ) 5 (9 ) 14 Long-term debt: Of Fannie Mae: Senior floating $ (955 ) $ (115 ) $ — $ — $ — $ (750 ) $ 19 $ 1,465 $ — $ (336 ) $ (70 ) Of consolidated trusts (518 ) (48 ) — — — (1 ) 51 100 (72 ) (488 ) (45 ) Total long-term debt $ (1,473 ) $ (163 ) (6) $ — $ — $ — $ (751 ) $ 70 $ 1,565 $ (72 ) $ (824 ) $ (115 ) __________ (1) Gains (losses) included in other comprehensive income are included in “Changes in unrealized gains on AFS securities, net of reclassification adjustments and taxes” in the 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 out of Level 3 consisted primarily of private-label mortgage-related securities backed by Alt-A loans and credit risk sharing securities issued under our CAS series. Prices for these securities were obtained from multiple third-party vendors or dealers. Transfers out of Level 3 also occurred for mortgage loans for which unobservable inputs used in valuations became less significant. Transfers into Level 3 consisted primarily of private-label mortgage-related securities backed by Alt-A loans. Prices for these securities are based on inputs from a single source or inputs that were not readily observable. (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 September 30, 2015 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: Alt-A private-label securities (2) $ 64 Consensus Default Rate (%) 1.6 1.6 Prepayment Speed (%) 3.7 3.7 Severity (%) 61.7 61.7 Spreads (bps) 266.1 266.1 251 Discounted Cash Flow Default Rate (%) 1.5 - 3.0 2.7 Prepayment Speed (%) 4.0 4.0 Severity (%) 55.0 - 95.0 88.1 Spreads (bps) 222.5 - 230.4 229.0 Total Alt-A private-label securities 315 Subprime private-label securities (2) 479 Consensus Default Rate (%) 4.0 - 10.3 6.5 Prepayment Speed (%) 1.0 - 4.6 2.3 Severity (%) 41.8 - 95.0 75.5 Spreads (bps) 275.0 - 280.0 275.4 169 Discounted Cash Flow Default Rate (%) 4.0 - 8.0 5.0 Prepayment Speed (%) 2.0 - 3.3 2.4 Severity (%) 60.0 - 78.0 65.2 Spreads (bps) 203.0 - 300.0 225.7 48 Other Total subprime private-label securities 696 Mortgage revenue bonds 563 Discounted Cash Flow Spreads (bps) 24.5 - 371.8 274.8 16 Other Total mortgage revenue bonds 579 Total trading securities $ 1,590 Fair Value Measurements as of September 30, 2015 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Available-for-sale securities: Mortgage-related securities: Agency (3) $ 4 Other Alt-A private-label securities (2) 598 Consensus Default Rate (%) 0.4 - 12.2 4.3 Prepayment Speed (%) 0.2 - 31.8 14.5 Severity (%) 6.8 - 95.0 66.5 Spreads (bps) 197.0 - 245.0 242.7 545 Consensus 313 Discounted Cash Flow Default Rate (%) 4.0 - 7.0 4.5 Prepayment Speed (%) 3.0 - 10.0 5.0 Severity (%) 50.0 - 85.0 63.5 Spreads (bps) 201.6 - 481.0 289.2 38 Other Total Alt-A private-label securities 1,494 Subprime private-label securities (2) 2,365 Consensus Default Rate (%) 0.5 - 19.3 7.7 Prepayment Speed (%) 0.3 - 13.2 3.4 Severity (%) 14.5 - 95.0 78.5 Spreads (bps) 245.0 - 280.0 273.7 774 Consensus 265 Discounted Cash Flow Default Rate (%) 5.6 - 12.0 7.8 Prepayment Speed (%) 1.0 - 4.0 1.9 Severity (%) 59.0 - 95.0 80.4 Spreads (bps) 169.4 - 315.0 225.4 273 Other Total subprime private-label securities 3,677 Mortgage revenue bonds 1,126 Single Vendor Spreads (bps) 7.0 - 347.9 62.8 1,607 Discounted Cash Flow Spreads (bps) 7.0 - 407.9 275.5 200 Other Total mortgage revenue bonds 2,933 Other 737 Consensus Default Rate (%) 0.0 - 4.6 3.4 Prepayment Speed (%) 2.5 - 17.4 4.5 Severity (%) 3.1 - 95.0 67.1 Spreads (bps) 195.0 - 466.3 334.1 550 Discounted Cash Flow Default Rate (%) 0.0 - 4.9 0.2 Prepayment Speed (%) 0.0 - 2.0 0.1 Severity (%) 25.0 - 95.0 90.6 Spreads (bps) 245.0 - 350.0 330.3 157 Other Total other 1,444 Total available-for-sale securities $ 9,552 Fair Value Measurements as of September 30, 2015 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Mortgage loans: Single-family $ 107 Build-Up Default Rate (%) 0.0 - 98.8 35.7 Prepayment Speed (%) 3.0 - 100.0 10.4 Severity (%) 0.0 - 100.0 38.5 667 Build-Up 236 Consensus 258 Consensus Default Rate (%) 0.0 - 7.6 3.3 Prepayment Speed (%) 3.2 - 30.3 5.9 Severity (%) 20.0 - 95.0 78.8 Spreads (bps) 243.4 - 278.0 253.5 71 Other Total single-family 1,339 Multifamily 161 Build-Up Spreads (bps) 61.0 - 334.2 161.1 Total mortgage loans $ 1,500 Net derivatives $ (115 ) Internal Model 162 Dealer Mark 13 Other Total net derivatives $ 60 Long-term debt: Of Fannie Mae: Senior floating $ (369 ) Discounted Cash Flow Of consolidated trusts (4) (127 ) Consensus (194 ) Consensus Default Rate (%) 0.0 - 4.0 3.1 Prepayment Speed (%) 3.5 - 30.3 5.4 Severity (%) 20.0 - 95.0 78.0 Spreads (bps) 243.4 - 260.0 254.8 (250 ) Other Total of consolidated trusts (571 ) Total long-term debt $ (940 ) Fair Value Measurements as of December 31, 2014 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 (3)(4) $ 153 Single Vendor Prepayment Speed (%) 100.0 100.0 Spreads (bps) 256.5 - 350.8 293.4 130 Consensus Prepayment Speed (%) 100.0 100.0 Spreads (bps) 184.6 - 219.5 197.5 22 Other Total Agency 305 Alt-A private-label securities (2) 290 Single Vendor Default Rate (%) 8.3 - 9.1 8.5 Prepayment Speed (%) 2.9 - 3.2 3.1 Severity (%) 79.5 - 95.0 90.4 Spreads (bps) 267.2 - 308.2 279.4 66 Consensus Default Rate (%) 5.4 5.4 Prepayment Speed (%) 7.0 7.0 Severity (%) 48.8 48.8 Spreads (bps) 264.8 264.8 151 Consensus 90 Other Total Alt-A private-label securities 597 Subprime private-label securities (2) 422 Consensus Default Rate (%) 3.5 - 11.8 7.2 Prepayment Speed (%) 1.4 - 5.2 2.8 Severity (%) 72.1 - 95.0 85.9 Spreads (bps) 265.0 265.0 549 Consensus 290 Discounted Cash Flow Default Rate (%) 4.3 - 6.2 5.2 Prepayment Speed (%) 2.3 - 4.2 3.3 Severity (%) 62.2 - 95.0 73.8 Spreads (bps) 265.0 - 382.1 283.7 46 Other Total subprime private-label securities 1,307 Mortgage revenue bonds 161 Dealer Mark Spreads (bps) 288.1 288.1 540 Discounted Cash Flow Spreads (bps) 6.0 - 318.0 263.0 21 Other Total mortgage revenue bonds 722 Other 99 Dealer Mark Total trading securities $ 3,030 Fair Value Measurements as of December 31, 2014 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Available-for-sale securities: Mortgage-related securities: Agency (3) $ 6 Other Alt-A private-label securities (2) 322 Single Vendor Default Rate (%) 0.2 - 13.1 4.6 Prepayment Speed (%) 0.2 - 20.5 8.2 Severity (%) 27.8 - 89.7 61.0 Spreads (bps) 190.0 - 315.0 264.9 493 Single Vendor 1,187 Consensus Default Rate (%) 0.4 - 31.2 5.1 Prepayment Speed (%) 0.1 - 48.9 11.0 Severity (%) 0.2 - 95.0 59.6 Spreads (bps) 183.8 - 240.0 236.7 691 Consensus 403 Discounted Cash Flow Default Rate (%) 5.0 - 11.5 7.0 Prepayment Speed (%) 0.5 - 8.4 3.4 Severity (%) 35.1 - 92.4 54.2 Spreads (bps) 188.0 - 340.0 243.4 44 Other Total Alt-A private-label securities 3,140 Subprime private-label securities (2) 383 Single Vendor Default Rate (%) 2.1 - 8.3 5.5 Prepayment Speed (%) 1.5 - 3.3 2.1 Severity (%) 65.4 - 95.0 78.5 Spreads (bps) 215.0 - 262.0 230.0 2,722 Consensus Default Rate (%) 1.5 - 37.4 6.3 Prepayment Speed (%) 0.1 - 17.7 2.6 Severity (%) 1.5 - 95.0 84.4 Spreads (bps) 155.0 - 265.0 220.0 1,755 Consensus 317 Discounted Cash Flow Default Rate (%) 3.0 - 12.3 7.0 Prepayment Speed (%) 1.1 - 9.0 4.1 Severity (%) 28.9 - 91.8 81.2 Spreads (bps) 155.0 - 895.0 250.5 63 Other Total subprime private-label securities 5,240 Mortgage revenue bonds 1,504 Single Vendor Spreads (bps) (11.5 ) - 361.5 52.7 418 Single Vendor 510 Dealer Mark Spreads (bps) 222.8 - 322.1 265.9 1,581 Discounted Cash Flow Spreads (bps) (11.5 ) - 620.2 251.4 10 Other Total mortgage revenue bonds 4,023 Other 337 Single Vendor Default Rate (%) 1.7 - 5.0 4.4 Prepayment Speed (%) 3.0 - 9.3 3.8 Severity (%) 4.0 - 94.6 69.6 Spreads (bps) 263.1 - 427.2 291.5 720 Consensus Default Rate (%) 0.1 - 6.6 3.9 Prepayment Speed (%) 3.0 - 30.4 4.8 Severity (%) 0.4 - 95.0 62.4 Spreads (bps) 215.0 - 481.4 320.6 1,215 Dealer Mark 399 Other Total other 2,671 Total available-for-sale securities $ 15,080 Fair Value Measurements as of December 31, 2014 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Mortgage loans: Single-family $ 934 Build-Up Default Rate (%) 0.0 - 99.0 14.9 Prepayment Speed (%) 3.6 - 99.8 16.3 Severity (%) 3.4 - 100.0 23.7 279 Consensus 402 Discounted Cash Flow Default Rate (%) 2.7 - 13.1 5.5 Prepayment Speed (%) 0.1 - 13.5 7.5 Severity (%) 35.5 - 95.0 61.3 Spreads (bps) 155.0 - 665.0 227.4 39 Other Total single-family 1,654 Multifamily 179 Build-Up Spreads (bps) 59.0 - 323.4 137.3 Total mortgage loans $ 1,833 Net derivatives $ (107 ) Internal Model 150 Dealer Mark 2 Other Total net derivatives $ 45 Long-term debt: Of Fannie Mae: Senior floating $ (363 ) Discounted Cash Flow Of consolidated trusts (4) (219 ) Consensus (205 ) Discounted Cash Flow Default Rate (%) 2.7 - 11.9 4.0 Prepayment Speed (%) 0.1 - 100.0 33.4 Severity (%) 35.5 - 95.0 54.6 Spreads (bps) 88.0 - 665.0 249.4 (103 ) Other Total of consolidated trusts (527 ) Total long-term debt $ (890 ) _________ (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. (2) Default Rate as disclosed represents the estimated beginning annualized rate of default and is used as a basis to forecast the future default rates that serve as an input for valuation. (3) Includes Fannie Mae and Freddie Mac securities. (4) Includes instruments for which the prepayment speed as disclosed represents the estimated annualized rate of prepayment after all prepayment penalty provisions have expired and also instruments for which prepayment speed as disclosed 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 that were measured at fair value on a nonrecurring basis as of September 30, 2015 or December 31, 2014 . We held $21 million and $93 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 September 30, 2015 and December 31, 2014 , 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 (Level 3) as of Valuation Techniques September 30, 2015 December 31, 2014 (Dollars in millions) Nonrecurring fair value measurements: Mortgage loans held for sale, at lower of cost or fair value Consensus $ 2,251 $ 110 Single Vendor 431 — Other 2 — Total mortgage loans held for sale, at lower of cost or fair value 2,684 110 Single-family mortgage loans held for investment, at amortized cost Internal Model 8,585 16,654 Other — 60 Total single-family mortgage loans held for investment, at amortized cost 8,585 16,714 Multifamily mortgage loans held for investment, at amortized cost Broker Price Opinions 90 45 Asset Manager Estimate 289 580 Other 7 — Total multifamily mortgage loans held for investment, at amortized cost 386 625 Acquired property, net: Single-family Accepted Offers 620 864 Appraisals 865 1,509 Walk Forwards 637 1,173 Internal Model 970 1,045 Other 122 191 Total single-family 3,214 4,782 Multifamily Broker Price Opinions 31 127 Other 2 13 Total multifamily 33 140 Other assets Other 27 45 Total nonrecurring assets at fair value $ 14,929 $ 22,416 We use valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. The following is a description of 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. Trading Securities and Available-for-Sale Securities These securities are recorded in our condensed consolidated balance sheets at fair value on a recurring basis. Fair value is measured using quoted market prices in active markets for identical assets, when available. We classify securities whose values are based on quoted market prices in active markets for identical assets as Level 1 of the valuation hierarchy. We classify securities in active markets as Level 2 of the valuation hierarchy if quoted market prices in active markets for identical assets are not available. For all valuation techniques used for securities where there is limited activity or less transparency around these inputs to the valuation, these securities are classified as Level 3 of the valuation hierarchy. A description of our securities valuation techniques is as follows: Single Vendor: This valuation technique utilizes one vendor price to estimate fair value. We generally validate these observations of fair value through the use of a discounted cash flow technique whose unobservable inputs (for example, default rates) are disclosed in the table above. Dealer Mark: This valuation technique utilizes one dealer price to estimate fair value. We generally validate these observations of fair value through the use of a discounted cash flow technique whose unobservable inputs (for example, default rates) are disclosed in the table above. Consensus: This technique utilizes an average of two or more vendor prices for similar securities. We generally validate these observations of fair value through the use of a discounted cash flow technique whose unobservable inputs (for example, default rates) are disclosed in the table above. Discounted Cash Flow: In the absence of prices provided by third-party pricing services supported by observable market data, we estimate the fair value of a portion of our securities using a discounted cash flow technique that uses inputs such as default rates, prepayment speeds, loss severity and spreads based on market assumptions where available. For private-label securities, an increase in unobservable prepayment speeds in isolation would generally result in an increase in fair value, and an increase in unobservable spreads, severity rates or default rates in isolation would generally result in a decrease in fair value. For mortgage revenue bonds classified as Level 3 of the valuation hierarchy, an increase in unobservable spreads would result in a decrease in fair value. Although the sensitivities of the fair value of our recurring Level 3 securities of the valuation hierarchy to various unobservable inputs are discussed above in isolation, interrelationships exist among these inputs such that a change in one unobservable input typically results in a change to one or more of the other inputs. Mortgage Loans Held for Investment The majority of HFI loans are reported in our condensed consolidated balance sheets at the principal amount outstanding, net of cost basis adjustments and an allowance for loan losses. We estimate the fair value of HFI loans using the build-up and consensus valuation techniques, as discussed below, for periodic disclosure of financial instruments as required by GAAP. For our remaining loans, which include those containing embedded derivatives that would otherwise require bifurcation and consolidated loans of senior-subordinated trust structures, we elected the fair value option and therefore, we record these loans at fair value in our condensed consolidated balance sheets. We measure these loans on a recurring basis using the build-up, consensus, discounted cash flow and single vendor price techniques. Certain impaired loans are measured at fair value on a nonrecurring basis by using the fair value of their underlying collateral. Specific techniques used include internal models, broker price opinions and appraisals. A description of our loan valuation techniques is as follows: Build-up: We derive the fair value of mortgage loans using a build-up valuation technique. In the build-up valuation technique we start with the base value for our Fannie Mae MBS and then add or subtract the fair value of the associated guaranty asset, guaran

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2015
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, reserves 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 a reserve 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 a reserve. 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 a reserve, 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. In re 2008 Fannie Mae ERISA Litigation In a consolidated complaint filed in 2009 in the U.S. District Court for the Southern District of New York, plaintiffs alleged that certain of our current and former officers and directors, including members of Fannie Mae’s Benefit Plans Committee and the Compensation Committee of Fannie Mae’s Board of Directors during the relevant time periods, as fiduciaries of Fannie Mae’s Employee Stock Ownership Plan (“ESOP”), breached their duties to ESOP participants and beneficiaries by investing ESOP funds in Fannie Mae common stock when it was no longer prudent to continue to do so. Plaintiffs purported to represent a class of participants and beneficiaries of the ESOP whose accounts invested in Fannie Mae common stock beginning April 17, 2007. Plaintiffs sought unspecified damages, attorneys’ fees and other fees and costs, and injunctive and other equitable relief. On October 31, 2014, we reached an agreement in principle with plaintiffs that would resolve this matter on behalf of all parties. The proposed settlement amount did not impact our results of operations or financial condition. On April 17, 2015, plaintiffs filed a motion for preliminary approval of the settlement, which the court granted on May 5, 2015. On August 13, 2015, the court granted final approval of the settlement. 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 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 October 27, 2014, the U.S. Court of Appeals for the D.C. Circuit consolidated these appeals with appeals in two other cases involving the same subject matter, but to which we are not a party. 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.

Summary of Significant Accoun23

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2015
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 accounting principles generally accepted in the United States of America (“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 nine months ended September 30, 2015 may not necessarily be indicative of the results for the year ending December 31, 2015. The unaudited interim condensed consolidated financial statements as of and for the nine months ended September 30, 2015 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, 2014 (“2014 Form 10-K”), filed with the SEC on February 20, 2015. Changes in Accounting Principle—Nonaccrual Loans Effective January 1, 2015, we changed our policy for the treatment of interest previously accrued but not collected at the date both single-family and multifamily loans are placed on nonaccrual status. Specifically, interest previously accrued but not collected will be reversed through interest income at the date a loan is placed on nonaccrual status. Previously, when a loan was placed on nonaccrual status, interest previously accrued but not collected became part of each loan’s recorded investment and was reviewed either individually or collectively for impairment. We also changed our policy for when a non-modified single-family loan is returned to accrual status. Effective January 1, 2015, a non-modified single-family loan will be returned to accrual status at the point that the borrower brings the loan current. Previously, a non-modified single-family loan was returned to accrual status at the point that the borrower had made sufficient payments to reduce the delinquency status below our nonaccrual threshold of 60 days past due. We have concluded that these changes in accounting principle are preferable as we align our nonaccrual policy with industry practice. This alignment increases comparability of our financial statements to these entities, resulting in improved financial reporting. As these changes to our nonaccrual policy were not material to our financial statements, we wrote off the accrued interest receivable balance on our nonaccrual loans, as well as the corresponding allowance that related to that interest, as an adjustment to the 2015 provision for loan losses and did not retrospectively adjust the condensed consolidated financial statements for this change. Change in Accounting Principle—Loans Held for Sale Effective January 1, 2015, we changed our policy for calculating the lower of cost or fair value adjustment on loans that have been designated as held for sale (“HFS”). Specifically, our lower of cost or fair value calculation will be performed at an individual loan level on the date of redesignation, if previously held for investment (“HFI”), and for all subsequent periods in which a loan is classified as HFS. Previously, the initial lower of cost or fair value adjustment on the date of re-designation was calculated at a loan level whereas the subsequent lower of cost or fair value adjustments were calculated at a pool level. We have concluded that this change in accounting policy is preferable as it will align the unit of account that is used for both the initial and subsequent lower of cost or market measurements on our HFS portfolio. Additionally, by performing the lower of cost or fair value calculation at the loan level, the adjustment will be calculated on a more disaggregated basis. As this change in accounting policy is not material to our financial statements, we recorded the impact of this change in accounting principle as an adjustment to 2015 fair value losses, net and did not retrospectively adjust the condensed consolidated financial statements for this change.
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 and other assets and liabilities, recoverability of our deferred tax assets and allowance for loan losses. Actual results could be different from these estimates. In April 2012, FHFA issued Advisory Bulletin AB 2012-02, “Framework for Adversely Classifying Loans, Other Real Estate Owned, and Other Assets and Listing Assets for Special Mention” (the “Advisory Bulletin”), which prescribes, among other things, classification of loans by risk category and provides guidance on when a loan should be charged off. The provisions of the Advisory Bulletin led us to re-evaluate our estimate of when a loan is deemed uncollectible. For the vast majority of our delinquent single-family loans, we will continue to charge off the loan at the date of foreclosure or other liquidation event (such as a deed-in-lieu of foreclosure or a short sale). For a relatively small subset of delinquent loans deemed to be uncollectible prior to foreclosure based upon our historical data, we charge off the portion of the loan (including preforeclosure property taxes and insurance receivable that pertain to such loans) deemed to be uncollectible prior to the date of foreclosure or other liquidation event, which given our current credit analytics and historical data, is when the loans are excessively delinquent and the outstanding loan balance exceeds the fair value of the underlying property. This change in estimate resulted in the recognition on January 1, 2015 of (1) $1.8 billion in charge-offs of HFI loans, (2) $ 724 million in charge-offs of preforeclosure property taxes and insurance receivable and (3) a reduction to our allowance for loan losses and our allowance for preforeclosure property taxes and insurance receivable in amounts equal to charge-offs recognized in connection with HFI loans and preforeclosure property taxes and insurance receivable. We continue to enhance our data collection and analysis efforts to further refine our loss estimates as we obtain incremental information on the performance of our loans.
New Accounting Pronouncements, Policy [Policy Text Block]	New Accounting Guidance Effective January 1, 2015, we prospectively adopted guidance issued by the Financial Accounting Standards Board (“FASB”) clarifying when a creditor is considered to have received physical possession of residential real estate property collateralized by a consumer mortgage loan. The adoption of this guidance resulted in a clarification to our policy to align our definition of when we have taken physical possession of real estate with the new guidance; however it did not impact the timing of derecognition of loan receivable and recognition of real estate property in our financial statements. The new guidance also requires us to disclose the recorded investment in consumer mortgage loans collateralized by residential real estate property that are in the process of foreclosure. See “Note 3 , Mortgage Loans ” for additional information regarding the disclosure required upon adoption of this guidance. Effective January 1, 2015, we prospectively adopted guidance issued by the FASB related to the classification of government guaranteed mortgage loans upon foreclosure. The impact of the adoption was not material to the condensed consolidated balance sheets. In February 2015, the FASB issued guidance regarding consolidation of legal entities such as limited partnerships, limited liability corporations and securitization structures. The guidance removes the specialized consolidation model surrounding limited partnerships and similar entities and amends the requirements that such entities must meet to qualify as voting interest entities. In addition, the guidance eliminates certain of the conditions for evaluating whether fees paid to a decision maker or service provider represent a variable interest. The new guidance is effective for us on January 1, 2016 with early adoption permitted. We are currently evaluating the potential impact of the new guidance on our consolidated financial statements.

Consolidations and Transfers 24

Consolidations and Transfers of Financial Assets (Policies)	9 Months Ended
	Sep. 30, 2015
Consolidations and Transfers of Financial Assets [Abstract]
Consolidations, Policy [Policy Text Block]	We have interests in various entities that are considered to be variable interest entities (“VIEs”). The primary types of entities are securitization trusts guaranteed by us via lender swap and portfolio securitization transactions and mortgage-backed trusts that were not created by us, as well as housing partnerships that are established to finance the acquisition, construction, development or rehabilitation of affordable multifamily and single-family housing. 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 Policy (Policies

Mortgage Loans Policy (Policies)	9 Months Ended
	Sep. 30, 2015
Mortgage Loans on Real Estate [Abstract]
Finance, Loan and Lease Receivables, Held-for-investment, Policy [Policy Text Block]	We report the recorded investment of HFI loans at the 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 our condensed consolidated statements of operations and comprehensive income.
Nonaccrual Loans [Policy Text Block]	Nonaccrual Policy We discontinue accruing interest on loans when we believe collectability 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. We generally place a multifamily loan on nonaccrual status when the loan is deemed to be individually impaired, unless the loan is well secured such that collectability of principal and accrued interest is reasonably assured. Effective January 1, 2015, we changed our policy for the treatment of interest previously accrued but not collected at the date both single-family and multifamily loans are placed on nonaccrual status. Specifically, interest previously accrued but not collected will be reversed through interest income at the date a loan is placed on nonaccrual status. Previously, when a loan was placed on nonaccrual status, interest previously accrued but not collected became part of the loan’s recorded investment and was reviewed either individually or collectively for impairment. We also changed our policy for when a non-modified single-family loan is returned to accrual status. Effective January 1, 2015, a non-modified single-family loan will be returned to accrual status at the point that the borrower brings the loan current. Previously, a non-modified single-family loan was returned to accrual status at the point that the borrower had made sufficient payments to reduce their delinquency status below our nonaccrual threshold of 60 days past due. We did not change our policy for returning modified single-family loans to accrual status. We return modified single-family loans to accrual status at the point that the borrower successfully makes all required payments during the trial period (generally three to four months) and modification is made permanent. See “Note 1, Summary of Significant Accounting Policies” for additional information on such changes in accounting policy. Changes to our nonaccrual policy were limited to those described above. For most single-family loans, we continue to recognize interest income for loans on nonaccrual status when cash is received. However, if a single-family loan was charged off prior to foreclosure, all payments received are applied on a cost recovery basis to reduce principal on the mortgage loan. We stop applying the cost recovery approach on those single-family loans when they are brought current either through borrower payments or modification and there has been a sufficient performance period to demonstrate that the borrower has the ability and intent to make the remaining payments on their mortgage loans. For multifamily loans, we apply any payment received on a cost recovery basis to reduce principal on the mortgage loan unless the loan is determined to be well secured. We generally return a multifamily loan to accrual status and stop applying the cost recovery approach when the borrower cures the delinquency of the loan or we otherwise determine that the loan is well secured such that collectability is reasonably assured.
Troubled Debt Restructurings [Policy Text Block]	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. In addition to formal loan modifications, we also engage in other loss mitigation activities with troubled borrowers, which include repayment plans and forbearance arrangements, both of which represent informal agreements with the borrower that do not result in the legal modification of the loan’s contractual terms. We account for these informal restructurings as a TDR if we defer more than three missed payments. We also classify loans to certain borrowers who have received bankruptcy relief as TDRs.

Allowance for Loan Losses Polic

Allowance for Loan Losses Policy (Policies)	9 Months Ended
	Sep. 30, 2015
Loans and Leases Receivable, Allowance [Abstract]
Allowance for Loan Losses [Policy Text Block]	Our allowance for loan losses is a valuation allowance that reflects an estimate of incurred credit losses related to our recorded investment in both single-family and multifamily HFI loans. This population includes both HFI loans held by Fannie Mae and by consolidated Fannie Mae MBS trusts. When calculating our allowance for loan losses, we consider only our net recorded investment in the loan at the balance sheet date, which includes the loan’s unpaid principal balance and any applicable cost basis adjustments. We record charge-offs as a reduction to the allowance for loan losses when losses are confirmed through the receipt of assets in full satisfaction of a loan, such as the underlying collateral upon foreclosure or cash upon completion of a short sale. Additionally, we record charge-offs as a reduction to our allowance for loan losses when a loan is determined to be uncollectible and upon the redesignation of nonperforming loans from HFI to HFS. 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. 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. When a loan has been restructured, we measure impairment using a cash flow analysis discounted at the loan’s original effective interest rate. However, 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 and other credit enhancements. 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. We establish a collective loss reserve 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.

Investment in Securities Polici

Investment in Securities Policies (Policies)	9 Months Ended
	Sep. 30, 2015
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 gains (losses), net” in our condensed consolidated statements of operations and comprehensive income.
Marketable Securities, Available-for-sale Securities, Policy [Policy Text Block]	Available-for-Sale Securities We measure 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.

Acquired Property Net (Policies

Acquired Property Net (Policies)	9 Months Ended
	Sep. 30, 2015
Real Estate [Abstract]
Acquired Property Held-For-Sale Foreclosed Assets Policy [Policy Text Block]	Acquired property, net consists of held-for-sale foreclosed property received in satisfaction of a loan, net of a valuation allowance for declines in the fair value of the properties after initial acquisition. We classify properties as held for sale when we intend to sell the property and are actively marketing it for sale.

Derivative Instruments (Policie

Derivative Instruments (Policies)	9 Months Ended
	Sep. 30, 2015
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 15 , 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. 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.

Segment Reporting Policy (Polic

Segment Reporting Policy (Policies)	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Segment Reporting, Policy [Policy Text Block]	Our three reportable segments are: Single-Family, Multifamily and Capital Markets. We use these three segments to generate revenue and manage business risk, and each segment is based on the type of business activities it performs. Under our segment reporting, the sum of the results for our three business segments does not equal our condensed consolidated statements of operations and comprehensive income, as we separate the activity related to our consolidated trusts from the results generated by our three segments. Our business segment financial results include directly attributable revenues and expenses. Additionally, we allocate to each of our segments: (1) capital using FHFA minimum capital requirements adjusted for over- or under-capitalization; (2) indirect administrative costs; and (3) a provision or benefit for federal income taxes. In addition, we allocate intracompany guaranty fee income as a charge from the Single-Family and Multifamily segments to Capital Markets for managing the credit risk on mortgage loans held by the Capital Markets group. We also include an eliminations/adjustments category to reconcile our business segment financial results and the activity related to our consolidated trusts to net income in our condensed consolidated statements of operations and comprehensive income.

Netting Arrangements (Policies)

Netting Arrangements (Policies)	9 Months Ended
	Sep. 30, 2015
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)	9 Months Ended
	Sep. 30, 2015
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 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 P

Commitments and Contingencies Policy (Policies)	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies, Policy [Policy Text Block]	On a quarterly basis, we review relevant information about all pending legal actions and proceedings for the purpose of evaluating and revising our contingencies, reserves and disclosures. We establish a reserve 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 a reserve.

Consolidations and Transfers 34

Consolidations and Transfers of Financial Assets (Tables)	9 Months Ended
	Sep. 30, 2015
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 mortgage-backed trusts, as well as our maximum exposure to loss and the total assets of these unconsolidated mortgage-backed trusts. As of September 30, 2015 December 31, 2014 (Dollars in millions) Assets and liabilities recorded in our condensed consolidated balance sheets related to mortgage-backed trusts: Assets: Trading securities: Fannie Mae securities $ 4,977 $ 4,790 Non-Fannie Mae securities 5,933 7,073 Total trading securities 10,910 11,863 Available-for-sale securities: Fannie Mae securities 3,931 5,043 Non-Fannie Mae securities 16,259 22,776 Total available-for-sale securities 20,190 27,819 Other assets 102 111 Other liabilities (755 ) (1,440 ) Net carrying amount $ 30,447 $ 38,353 Maximum exposure to loss $ 36,637 $ 45,311 Total assets of unconsolidated mortgage-backed trusts $ 252,211 $ 253,554

Mortgage Loans (Tables)

Mortgage Loans (Tables)	9 Months Ended
	Sep. 30, 2015
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 September 30, 2015 December 31, 2014 Of Fannie Mae Of Consolidated Trusts Total Of Fannie Mae Of Consolidated Trusts Total (Dollars in millions) Single-family $ 242,496 $ 2,573,388 $ 2,815,884 $ 262,116 $ 2,569,884 $ 2,832,000 Multifamily 15,272 181,533 196,805 23,255 164,045 187,300 Total unpaid principal balance of mortgage loans 257,768 2,754,921 3,012,689 285,371 2,733,929 3,019,300 Cost basis and fair value adjustments, net (12,789 ) 49,691 36,902 (12,705 ) 48,440 35,735 Allowance for loan losses for loans held for investment (27,655 ) (1,480 ) (29,135 ) (33,117 ) (2,424 ) (35,541 ) Total mortgage loans $ 217,324 $ 2,803,132 $ 3,020,456 $ 239,549 $ 2,779,945 $ 3,019,494
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 September 30, 2015 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 $ 29,574 $ 7,766 $ 28,417 $ 65,757 $ 2,594,488 $ 2,660,245 $ 49 $ 36,108 Government (2) 57 25 295 377 41,342 41,719 295 — Alt-A 4,126 1,291 7,407 12,824 87,525 100,349 7 8,690 Other 1,562 489 2,447 4,498 33,730 38,228 7 2,922 Total single-family 35,319 9,571 38,566 83,456 2,757,085 2,840,541 358 47,720 Multifamily (3) 37 N/A 88 125 198,574 198,699 — 679 Total $ 35,356 $ 9,571 $ 38,654 $ 83,581 $ 2,955,659 $ 3,039,240 $ 358 $ 48,399 As of December 31, 2014 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 $ 29,130 $ 8,396 $ 38,248 $ 75,774 $ 2,580,446 $ 2,656,220 $ 55 $ 46,556 Government (2) 63 26 305 394 44,927 45,321 305 — Alt-A 4,094 1,414 11,603 17,111 95,650 112,761 8 13,007 Other 1,520 516 3,763 5,799 38,460 44,259 6 4,259 Total single-family 34,807 10,352 53,919 99,078 2,759,483 2,858,561 374 63,822 Multifamily (3) 60 N/A 89 149 189,084 189,233 — 823 Total $ 34,867 $ 10,352 $ 54,008 $ 99,227 $ 2,948,567 $ 3,047,794 $ 374 $ 64,645 __________ (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 September 30, 2015 December 31, 2014 Unpaid Principal Balance Total Recorded Investment Related Allowance for Loan Losses Unpaid Principal Balance Total Recorded Investment Related Allowance for Loan Losses Related Allowance for Accrued Interest Receivable (Dollars in millions) Individually impaired loans: With related allowance recorded: Single-family: Primary $ 118,495 $ 112,430 $ 17,374 $ 125,960 $ 120,221 $ 20,327 $ 309 Government 324 329 62 281 285 46 12 Alt-A 32,593 29,777 6,454 35,492 32,816 7,778 136 Other 13,217 12,489 2,514 14,667 13,947 3,049 38 Total single-family 164,629 155,025 26,404 176,400 167,269 31,200 495 Multifamily 788 793 113 1,230 1,241 175 6 Total individually impaired loans with related allowance recorded 165,417 155,818 26,517 177,630 168,510 31,375 501 With no related allowance recorded: (1) Single-family: Primary 16,930 15,600 — 16,704 14,876 — — Government 60 56 — 61 57 — — Alt-A 4,235 3,580 — 3,993 3,119 — — Other 1,356 1,218 — 1,240 1,056 — — Total single-family 22,581 20,454 — 21,998 19,108 — — Multifamily 364 366 — 565 568 — — Total individually impaired loans with no related allowance recorded 22,945 20,820 — 22,563 19,676 — — Total individually impaired loans (2) $ 188,362 $ 176,638 $ 26,517 $ 200,193 $ 188,186 $ 31,375 $ 501 For the Three Months Ended September 30, 2015 2014 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 $ 113,634 $ 1,090 $ 71 $ 121,246 $ 1,077 $ 111 Government 299 3 — 285 3 — Alt-A 30,041 272 14 33,458 268 24 Other 12,652 95 6 14,346 100 8 Total single-family 156,626 1,460 91 169,335 1,448 143 Multifamily 878 9 — 1,540 17 — Total individually impaired loans with related allowance recorded 157,504 1,469 91 170,875 1,465 143 With no related allowance recorded: (1) Single-family: Primary 15,627 279 16 14,442 226 56 Government 53 1 — 55 1 — Alt-A 3,674 64 1 2,887 51 14 Other 1,259 21 — 1,008 16 3 Total single-family 20,613 365 17 18,392 294 73 Multifamily 386 5 — 1,572 18 — Total individually impaired loans with no related allowance recorded 20,999 370 17 19,964 312 73 Total individually impaired loans (2) $ 178,503 $ 1,839 $ 108 $ 190,839 $ 1,777 $ 216 For the Nine Months Ended September 30, 2015 2014 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 $ 115,762 $ 3,152 $ 248 $ 122,443 $ 3,264 $ 372 Government 290 9 — 266 9 — Alt-A 30,760 774 41 33,926 805 74 Other 13,030 282 15 14,635 305 28 Total single-family 159,842 4,217 304 171,270 4,383 474 Multifamily 1,053 15 — 1,813 63 — Total individually impaired loans with related allowance recorded 160,895 4,232 304 173,083 4,446 474 With no related allowance recorded: (1) Single-family: Primary 15,967 779 76 13,514 616 157 Government 55 3 — 70 4 — Alt-A 3,720 158 8 2,687 135 34 Other 1,287 56 2 945 40 8 Total single-family 21,029 996 86 17,216 795 199 Multifamily 463 8 — 1,698 58 — Total individually impaired loans with no related allowance recorded 21,492 1,004 86 18,914 853 199 Total individually impaired loans (2) $ 182,387 $ 5,236 $ 390 $ 191,997 $ 5,299 $ 673 __________ (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 $174.6 billion and $185.2 billion as of September 30, 2015 and December 31, 2014 respectively. Includes multifamily loans restructured in a TDR with a recorded investment of $490 million and $716 million as of September 30, 2015 and December 31, 2014 , respectively. (3) Total single-family interest income recognized of $1.8 billion for the three months ended September 30, 2015 and 2014 consists of $1.5 billion and $1.4 billion of contractual interest, respectively, and $327 million and $297 million of effective yield adjustments, respectively. Total single-family interest income recognized of $5.2 billion for the nine months ended September 30, 2015 and 2014 consists of $4.3 billion of contractual interest for both periods and $907 million and $857 million of effective yield adjustments, respectively.
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 September 30, 2015 2014 Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 14,926 $ 2,021 23,057 $ 3,270 Government 54 6 91 12 Alt-A 1,805 268 3,175 521 Other 324 57 698 142 Total single-family 17,109 2,352 27,021 3,945 Multifamily 3 10 7 811 Total troubled debt restructurings 17,112 $ 2,362 27,028 $ 4,756 For the Nine Months Ended September 30, 2015 2014 Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 54,284 $ 7,443 76,831 $ 10,944 Government 192 22 264 33 Alt-A 7,127 1,101 11,231 1,875 Other 1,453 265 2,608 540 Total single-family 63,056 8,831 90,934 13,392 Multifamily 7 16 16 849 Total troubled debt restructurings 63,063 $ 8,847 90,950 $ 14,241 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 September 30, 2015 2014 Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 6,847 $ 1,003 8,798 $ 1,312 Government 31 3 38 6 Alt-A 1,052 183 1,372 241 Other 328 65 438 100 Total single-family 8,258 1,254 10,646 1,659 Multifamily — — 1 5 Total TDRs that subsequently defaulted 8,258 $ 1,254 10,647 $ 1,664 For the Nine Months Ended September 30, 2015 2014 Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 19,726 $ 2,870 25,586 $ 3,873 Government 88 12 74 9 Alt-A 3,168 537 4,212 753 Other 922 186 1,362 304 Total single-family 23,904 3,605 31,234 4,939 Multifamily 3 6 6 22 Total TDRs that subsequently defaulted 23,907 $ 3,611 31,240 $ 4,961
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 September 30, 2015 (1) December 31, 2014 (1) Primary Alt-A Other Primary Alt-A Other (Dollars in millions) Estimated mark-to-market loan-to-value ratio: (2) Less than or equal to 80% $ 2,248,367 $ 61,367 $ 22,263 $ 2,156,165 $ 60,851 $ 22,558 Greater than 80% and less than or equal to 90% 240,860 13,188 5,197 261,709 15,151 6,046 Greater than 90% and less than or equal to 100% 108,540 9,758 4,020 140,778 12,490 5,236 Greater than 100% and less than or equal to 110% 28,684 6,528 2,787 43,014 8,998 3,900 Greater than 110% and less than or equal to 120% 15,115 4,018 1,699 23,439 6,033 2,615 Greater than 120% and less than or equal to 125% 4,706 1,295 552 7,529 2,114 904 Greater than 125% 13,973 4,195 1,710 23,586 7,124 3,000 Total $ 2,660,245 $ 100,349 $ 38,228 $ 2,656,220 $ 112,761 $ 44,259 __________ (1) Excludes $41.7 billion and $45.3 billion as of September 30, 2015 and December 31, 2014 , 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 loan-to-value (“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 September 30, December 31, 2015 2014 (Dollars in millions) Credit risk profile by internally assigned grade: (1) Pass $ 192,767 $ 182,079 Special Mention 2,725 3,070 Substandard 3,203 3,842 Doubtful 4 242 Total $ 198,699 $ 189,233 _________ (1) Pass (loan is current and adequately protected by the current financial strength and debt service capacity of the borrower); special mention (loan with signs of potential weakness); substandard (loan with a well defined weakness that jeopardizes the timely full repayment); and doubtful (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 Table

Allowance for Loan Losses Table (Tables)	9 Months Ended
	Sep. 30, 2015
Loans and Leases Receivable, Allowance [Abstract]
Allowance for Loan Losses Rollforward by Segment [Table Text Block]	The following tables display changes in single-family, multifamily and total allowance for loan losses. For the Three Months Ended September 30, 2015 2014 Of Fannie Mae Of Consolidated Trusts Total Of Fannie Mae Of Consolidated Trusts Total (Dollars in millions) Single-family allowance for loan losses: Beginning balance $ 29,624 $ 1,252 $ 30,876 $ 36,400 $ 2,243 $ 38,643 Provision (benefit) for loan losses (1) (1,722 ) 330 (1,392 ) (1,393 ) 394 (999 ) Charge-offs (2) (748 ) (22 ) (770 ) (1,439 ) (108 ) (1,547 ) Recoveries 161 3 164 271 4 275 Transfers (3) 262 (262 ) — 366 (366 ) — Other (4) (13 ) — (13 ) 170 28 198 Ending balance $ 27,564 $ 1,301 $ 28,865 $ 34,375 $ 2,195 $ 36,570 Multifamily allowance for loan losses: Beginning balance $ 100 $ 174 $ 274 $ 243 $ 181 $ 424 Provision (benefit) for loan losses (1) (10 ) 8 (2 ) (46 ) (6 ) (52 ) Charge-offs (2) (5 ) (2 ) (7 ) (14 ) — (14 ) Recoveries 4 — 4 — — — Transfers (3) 1 (1 ) — 2 (2 ) — Other (4) 1 — 1 2 1 3 Ending balance $ 91 $ 179 $ 270 $ 187 $ 174 $ 361 Total allowance for loan losses: Beginning balance $ 29,724 $ 1,426 $ 31,150 $ 36,643 $ 2,424 $ 39,067 Provision (benefit) for loan losses (1) (1,732 ) 338 (1,394 ) (1,439 ) 388 (1,051 ) Charge-offs (2) (753 ) (24 ) (777 ) (1,453 ) (108 ) (1,561 ) Recoveries 165 3 168 271 4 275 Transfers (3) 263 (263 ) — 368 (368 ) — Other (4) (12 ) — (12 ) 172 29 201 Ending balance $ 27,655 $ 1,480 $ 29,135 $ 34,562 $ 2,369 $ 36,931 For the Nine Months Ended September 30, 2015 2014 Of Fannie Mae Of Consolidated Trusts Total Of Fannie Mae Of Consolidated Trusts Total (Dollars in millions) Single-family allowance for loan losses: Beginning balance $ 32,956 $ 2,221 $ 35,177 $ 40,202 $ 3,105 $ 43,307 Provision (benefit) for loan losses (1) (249 ) (44 ) (293 ) (3,563 ) 192 (3,371 ) Charge-offs (2)(5) (8,108 ) (64 ) (8,172 ) (4,747 ) (251 ) (4,998 ) Recoveries 1,032 15 1,047 902 222 1,124 Transfers (3) 877 (877 ) — 1,123 (1,123 ) — Other (4) 1,056 50 1,106 458 50 508 Ending balance $ 27,564 $ 1,301 $ 28,865 $ 34,375 $ 2,195 $ 36,570 Multifamily allowance for loan losses: Beginning balance $ 161 $ 203 $ 364 $ 319 $ 220 $ 539 Benefit for loan losses (1) (41 ) (23 ) (64 ) (66 ) (44 ) (110 ) Charge-offs (2)(5) (39 ) (2 ) (41 ) (73 ) — (73 ) Recoveries 4 — 4 — — — Transfers (3) 1 (1 ) — 4 (4 ) — Other (4) 5 2 7 3 2 5 Ending balance $ 91 $ 179 $ 270 $ 187 $ 174 $ 361 Total allowance for loan losses: Beginning balance $ 33,117 $ 2,424 $ 35,541 $ 40,521 $ 3,325 $ 43,846 Provision (benefit) for loan losses (1) (290 ) (67 ) (357 ) (3,629 ) 148 (3,481 ) Charge-offs (2)(5) (8,147 ) (66 ) (8,213 ) (4,820 ) (251 ) (5,071 ) Recoveries 1,036 15 1,051 902 222 1,124 Transfers (3) 878 (878 ) — 1,127 (1,127 ) — Other (4) 1,061 52 1,113 461 52 513 Ending balance $ 27,655 $ 1,480 $ 29,135 $ 34,562 $ 2,369 $ 36,931 __________ (1) Provision (benefit) for loan losses is included in “Benefit for credit losses” in our condensed consolidated statements of operations and comprehensive income. (2) While we purchase the substantial majority of loans that are four or more months delinquent from our MBS trusts, we do not exercise this option to purchase loans during a forbearance period. Charge-offs of consolidated trusts generally represent loans that remained in our consolidated trusts at the time of default. (3) Includes transfers from trusts for delinquent loan purchases. (4) Amounts represent changes in other loss reserves which are offset by amounts reflected in provision (benefit) for credit losses, charge-offs and recoveries. (5) Includes for the nine months ended September 30, 2015 charge-offs of (1) $1.8 billion in HFI loans and $ 724 million in preforeclosure property taxes and insurance receivable in connection with our adoption of the Advisory Bulletin on January 1, 2015 and (2) $ 1.1 billion in accrued interest receivable that were charged-off in connection with the our adoption of a change in accounting principle on January 1, 2015 related to the treatment of interest previously accrued, but not collected, at the date that loans are placed on nonaccrual status.
Allowance for Loan Losses and Total Recorded Investment in HFI Loans [Table Text Block]	The following table displays the allowance for loan losses and total recorded investment in our HFI loans, excluding loans for which we have elected the fair value option, by impairment or reserve methodology and portfolio segment. As of September 30, 2015 December 31, 2014 Single-Family Multifamily Total Single-Family Multifamily Total (Dollars in millions) Allowance for loan losses by segment: Individually impaired loans (1) $ 26,404 $ 113 $ 26,517 $ 31,200 $ 175 $ 31,375 Collectively reserved loans 2,461 157 2,618 3,977 189 4,166 Total allowance for loan losses $ 28,865 $ 270 $ 29,135 $ 35,177 $ 364 $ 35,541 Recorded investment in loans by segment: Individually impaired loans (1) $ 175,479 $ 1,159 $ 176,638 $ 186,377 $ 1,809 $ 188,186 Collectively reserved loans 2,665,062 197,540 2,862,602 2,672,184 187,424 2,859,608 Total recorded investment in loans $ 2,840,541 $ 198,699 $ 3,039,240 $ 2,858,561 $ 189,233 $ 3,047,794 __________ (1) Includes acquired credit-impaired loans.

Investments in Securities (Tabl

Investments in Securities (Tables)	9 Months Ended
	Sep. 30, 2015
Investments, Debt and Equity Securities [Abstract]
Investments In Trading Securities [Table Text Block]	The following table displays our investments in trading securities. As of September 30, 2015 December 31, 2014 (Dollars in millions) Mortgage-related securities: Fannie Mae $ 5,097 $ 4,940 Freddie Mac 1,474 1,369 Ginnie Mae 353 166 Alt-A private-label securities 451 920 Subprime private-label securities 696 1,307 CMBS 2,398 2,515 Mortgage revenue bonds 579 722 Other mortgage-related securities — 99 Total mortgage-related securities 11,048 12,038 U.S. Treasury securities 26,961 19,466 Total trading securities $ 38,009 $ 31,504
Schedule of Trading Securities Gains (Losses), Net [Table Text Block]	The following table displays information about our net trading gains and losses. For the Three For the Nine Months Ended Months Ended September 30, September 30, 2015 2014 2015 2014 (Dollars in millions) Net trading gains $ 13 $ 50 $ 69 $ 444 Net trading gains (losses) recognized in the period related to securities still held at period end (15 ) 56 (29 ) 409
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 Nine Months Ended Months Ended September 30, September 30, 2015 2014 2015 2014 (Dollars in millions) Gross realized gains $ 94 $ 96 $ 907 $ 495 Gross realized losses 9 4 66 5 Total proceeds (1) 1,556 722 6,764 2,461 __________ (1) Excludes proceeds from the initial sale of securities from new portfolio securitizations.
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 September 30, 2015 Total Amortized Cost (1) Gross Unrealized Gains Gross Unrealized Losses - OTTI (2) Gross Unrealized Losses - Other (3) Total Fair Value (Dollars in millions) Fannie Mae $ 4,026 $ 275 $ — $ (19 ) $ 4,282 Freddie Mac 4,252 347 — — 4,599 Ginnie Mae 361 52 — — 413 Alt-A private-label securities 2,626 727 (4 ) — 3,349 Subprime private-label securities 2,817 865 — (5 ) 3,677 CMBS 1,273 36 — — 1,309 Mortgage revenue bonds 2,824 129 (17 ) (3 ) 2,933 Other mortgage-related securities 1,408 40 (3 ) — 1,445 Total $ 19,587 $ 2,471 $ (24 ) $ (27 ) $ 22,007 As of December 31, 2014 Total Amortized Cost (1) Gross Unrealized Gains Gross Unrealized Losses - OTTI (2) Gross Unrealized Losses - Other (3) Total Fair Value (Dollars in millions) Fannie Mae $ 5,330 $ 328 $ — $ (19 ) $ 5,639 Freddie Mac 5,100 428 — — 5,528 Ginnie Mae 416 60 — — 476 Alt-A private-label securities 4,638 1,055 (15 ) — 5,678 Subprime private-label securities 4,103 1,161 (9 ) (15 ) 5,240 CMBS 1,341 56 — — 1,397 Mortgage revenue bonds 3,859 177 (8 ) (5 ) 4,023 Other mortgage-related securities 2,626 183 (23 ) (113 ) 2,673 Total $ 27,413 $ 3,448 $ (55 ) $ (152 ) $ 30,654 __________ (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 noncredit component of OTTI losses recorded in “Accumulated other comprehensive income” in our condensed consolidated balance sheets, as well as cumulative changes in fair value of securities for which we previously recognized the credit component of OTTI. (3) Represents the gross unrealized losses on securities for which we have not recognized OTTI.
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 September 30, 2015 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 $ (3 ) $ 116 $ (16 ) $ 511 Alt-A private-label securities (1 ) 132 (3 ) 28 Subprime private-label securities — 38 (5 ) 96 Mortgage revenue bonds (16 ) 584 (4 ) 20 Other mortgage-related securities (3 ) 255 — — Total $ (23 ) $ 1,125 $ (28 ) $ 655 As of December 31, 2014 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 $ — $ 113 $ (19 ) $ 627 Alt-A private-label securities (2 ) 171 (13 ) 112 Subprime private-label securities — — (24 ) 460 Mortgage revenue bonds (2 ) 47 (11 ) 155 Other mortgage-related securities — 8 (136 ) 1,021 Total $ (4 ) $ 339 $ (203 ) $ 2,375
Schedule of Modeled Attributes Used to Determine Potential Cash Shortfalls [Table Text Block]	The following table displays the modeled attributes, including default rates and severities, which were used to determine as of September 30, 2015 whether our senior interests in certain non-agency mortgage-related securities (including those we intend to sell) will experience a cash shortfall. An estimate of voluntary prepayment rates is also an input to the present value of expected losses. As of September 30, 2015 Alt-A Subprime Option ARM Fixed Rate Variable Rate Hybrid Rate (Dollars in millions) Total unpaid principal balance $ 4,917 $ 494 $ 1,205 $ 838 $ 1,237 Weighted average collateral default (1) 42.4 % 29.4 % 11.9 % 21.4 % 10.0 % Weighted average collateral severities (2) 60.0 38.5 46.9 37.9 34.2 Weighted average voluntary prepayment rates (3) 2.7 7.4 12.2 8.4 12.0 Average credit enhancement (4) 17.4 3.6 5.6 8.6 4.4 __________ (1) The expected remaining cumulative default rate of the collateral pool backing the securities, as a percentage of the current collateral unpaid principal balance, weighted by security unpaid principal balance. (2) The expected remaining loss given default of the collateral pool backing the securities, calculated as the ratio of remaining cumulative loss divided by cumulative defaults, weighted by security unpaid principal balance. (3) The average monthly voluntary prepayment rate, weighted by security unpaid principal balance. (4) The average percent current credit enhancement provided by subordination of other securities. Excludes excess interest projections and monoline bond insurance.
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Table Text Block]	The following table displays activity related to the unrealized credit loss component on debt securities held by us and recognized in our condensed consolidated statements of operations and comprehensive income. For the Three Months Ended September 30, For the Nine Months Ended September 30, 2015 2014 2015 2014 (Dollars in millions) Balance, beginning of period $ 2,557 $ 5,871 $ 5,260 $ 7,904 Additions for the credit component on debt securities for which OTTI was not previously recognized — — — 1 Additions for the credit component on debt securities for which OTTI was previously recognized 1 3 5 50 Reductions for securities no longer in portfolio at period end (2 ) (355 ) (1,167 ) (792 ) Reductions for securities which we intend to sell or it is more likely than not that we will be required to sell before recovery of amortized cost basis — — (1,439 ) (1,453 ) Reductions for amortization resulting from changes in cash flows expected to be collected over the remaining life of the securities (43 ) (73 ) (146 ) (264 ) Balance, end of period $ 2,513 $ 5,446 $ 2,513 $ 5,446
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 September 30, 2015 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 $ 4,026 $ 4,282 $ — $ — $ 189 $ 194 $ 165 $ 178 $ 3,672 $ 3,910 Freddie Mac 4,252 4,599 1 1 221 231 332 363 3,698 4,004 Ginnie Mae 361 413 — — 1 1 57 64 303 348 Alt-A private-label securities 2,626 3,349 — — — — — — 2,626 3,349 Subprime private-label securities 2,817 3,677 — — — — — — 2,817 3,677 CMBS 1,273 1,309 171 173 1,037 1,071 — — 65 65 Mortgage revenue bonds 2,824 2,933 11 11 106 108 219 221 2,488 2,593 Other mortgage-related securities 1,408 1,445 — — — — 31 33 1,377 1,412 Total $ 19,587 $ 22,007 $ 183 $ 185 $ 1,554 $ 1,605 $ 804 $ 859 $ 17,046 $ 19,358

Financial Guarantees (Tables)

Financial Guarantees (Tables)	9 Months Ended
	Sep. 30, 2015
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 September 30, 2015 December 31, 2014 Maximum Exposure (1) Guaranty Obligation Maximum Recovery (2) Maximum Exposure (1) Guaranty Obligation Maximum Recovery (2) (Dollars in millions) Unconsolidated Fannie Mae MBS $ 15,556 $ 198 $ 9,077 $ 17,184 $ 214 $ 9,775 Other guaranty arrangements (3) 16,783 140 2,971 18,781 168 4,447 Total $ 32,339 $ 338 $ 12,048 $ 35,965 $ 382 $ 14,222 __________ (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, see “ Note 13, Concentrations of Credit Risk .” (3) Primarily consists of credit enhancements, long-term standby commitments, and our commitment under the TCLF program.

Acquired Property Net (Tables)

Acquired Property Net (Tables)	9 Months Ended
	Sep. 30, 2015
Real Estate [Abstract]
Activity in acquired property and the related valuation allowance [Table Text Block]	The following table displays the activity in acquired property, and the related valuation allowance. For the Three Months Ended September 30, For the Nine Months Ended September 30, 2015 2014 2015 2014 (Dollars in millions) Beginning balance — Acquired property $ 9,199 $ 12,296 $ 11,442 $ 12,307 Additions 2,236 3,240 7,602 10,437 Disposals (3,125 ) (3,412 ) (10,734 ) (10,620 ) Ending balance — Acquired property 8,310 12,124 8,310 12,124 Beginning balance — Valuation allowance (693 ) (736 ) (824 ) (686 ) Decrease (increase) in valuation allowance 74 (49 ) 205 (99 ) Ending balance — Valuation allowance (619 ) (785 ) (619 ) (785 ) Ending balance — Acquired property, net $ 7,691 $ 11,339 $ 7,691 $ 11,339

Short-Term Borrowings and Lon40

Short-Term Borrowings and Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2015
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 September 30, 2015 December 31, 2014 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) $ 118 — % $ 50 — % Short-term debt of Fannie Mae $ 95,427 0.21 % $ 105,012 0.11 % Debt of consolidated trusts 1,391 0.15 1,560 0.09 Total short-term debt $ 96,818 0.20 % $ 106,572 0.11 % __________ (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 September 30, 2015 December 31, 2014 Maturities Outstanding Weighted- Average Interest Rate (1) Maturities Outstanding Weighted- Average Interest Rate (1) (Dollars in millions) Senior fixed: Benchmark notes and bonds 2015 - 2030 $ 159,550 2.51 % 2015 - 2030 $ 173,010 2.41 % Medium-term notes (2) 2015 - 2025 100,682 1.49 2015 - 2024 114,556 1.42 Foreign exchange bonds 2021 - 2028 570 5.39 2021 - 2028 619 5.44 Other 2015 - 2038 27,797 4.83 2015 - 2038 32,322 4.63 Total senior fixed 288,599 2.39 320,507 2.29 Senior floating: Medium-term notes (2) 2015 - 2019 19,164 0.22 2015 - 2019 24,469 0.15 Connecticut Avenue Securities (3) 2023 - 2025 9,607 3.39 2023 - 2024 6,041 2.97 Other (4) 2020 - 2037 369 8.25 2020 - 2037 363 8.71 Total senior floating 29,140 1.36 30,873 0.81 Subordinated debentures 2019 4,129 9.93 2019 3,849 9.93 Secured borrowings (5) 2021 - 2022 163 1.35 2021 - 2022 202 1.90 Total long-term debt of Fannie Mae (6) 322,031 2.39 355,431 2.24 Debt of consolidated trusts (4) 2015 - 2054 2,787,396 2.91 2015 - 2054 2,760,152 3.02 Total long-term debt $ 3,109,427 2.85 % $ 3,115,583 2.93 % __________ (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) Credit risk-sharing securities that transfer a portion of the credit risk on specified pools of mortgage loans to the investors in these securities. Connecticut Avenue Securities are reported at fair value. (4) Includes structured debt instruments that are reported at fair value. (5) 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. (6) Includes unamortized discounts and premiums, other cost basis adjustments and fair value adjustments of $3.4 billion and $4.1 billion as of September 30, 2015 and December 31, 2014 , respectively.

Derivative Instruments (Tables)

Derivative Instruments (Tables)	9 Months Ended
	Sep. 30, 2015
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 September 30, 2015 As of December 31, 2014 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 $ 7,557 $ 42 $ 151,810 $ (9,251 ) $ 41,965 $ 733 $ 123,557 $ (7,125 ) Receive-fixed 157,472 4,434 44,981 (145 ) 67,629 4,486 157,272 (1,302 ) Basis 764 148 10,600 (2 ) 5,769 123 7,100 (2 ) Foreign currency 302 116 265 (46 ) 344 144 273 (30 ) Swaptions: Pay-fixed 6,300 43 13,950 (24 ) 11,100 57 26,525 (175 ) Receive-fixed — — 14,200 (283 ) 750 96 29,525 (816 ) Other (1) 3,956 25 1,993 (1 ) 1,071 28 12 (1 ) Total gross risk management derivatives 176,351 4,808 237,799 (9,752 ) 128,628 5,667 344,264 (9,451 ) Accrued interest receivable (payable) — 835 — (1,220 ) — 749 — (1,013 ) Netting adjustment (2) — (4,417 ) — 10,635 — (5,186 ) — 10,194 Total net risk management derivatives $ 176,351 $ 1,226 $ 237,799 $ (337 ) $ 128,628 $ 1,230 $ 344,264 $ (270 ) Mortgage commitment derivatives: Mortgage commitments to purchase whole loans $ 9,595 $ 57 $ 28 $ — $ 6,157 $ 28 $ 428 $ — Forward contracts to purchase mortgage-related securities 57,746 326 2,245 (4 ) 43,533 223 6,112 (8 ) Forward contracts to sell mortgage-related securities 1,623 1 87,416 (563 ) 4,886 4 57,910 (336 ) Total mortgage commitment derivatives $ 68,964 $ 384 $ 89,689 $ (567 ) $ 54,576 $ 255 $ 64,450 $ (344 ) Derivatives at fair value $ 245,315 $ 1,610 $ 327,488 $ (904 ) $ 183,204 $ 1,485 $ 408,714 $ (614 ) __________ (1) Includes futures and swap credit enhancements, as well as credit risk transfer transactions 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 $6.5 billion and $5.3 billion as of September 30, 2015 and December 31, 2014 , respectively. Cash collateral received was $256 million and $245 million as of September 30, 2015 and December 31, 2014 , 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 Ended For the Nine Months Ended Ended September 30, Ended September 30, 2015 2014 2015 2014 (Dollars in millions) Risk management derivatives: Swaps: Pay-fixed $ (4,402 ) $ 712 $ (3,120 ) $ (3,755 ) Receive-fixed 2,295 (822 ) 2,236 2,282 Basis 37 6 25 49 Foreign currency (20 ) (17 ) (33 ) 21 Swaptions: Pay-fixed 32 (53 ) 137 (90 ) Receive-fixed (102 ) 82 (181 ) (19 ) Other 22 (1 ) 20 (1 ) Accrual of periodic settlements: Pay-fixed interest-rate swaps (895 ) (939 ) (2,730 ) (2,755 ) Receive-fixed interest-rate swaps 620 613 2,007 1,946 Other 9 12 29 39 Total risk management derivatives fair value losses, net $ (2,404 ) $ (407 ) $ (1,610 ) $ (2,283 ) Mortgage commitment derivatives fair value losses, net (361 ) (73 ) (427 ) (728 ) Total derivatives fair value losses, net $ (2,765 ) $ (480 ) $ (2,037 ) $ (3,011 )

Earnings (Loss) Per Share (Tabl

Earnings (Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Schedule of Earnings (Loss) Per Share, Basic and Diluted [Table Text Block]	The following table displays the computation of basic and diluted earnings (loss) per share of common stock. For the Three Months Ended September 30, For the Nine Months Ended September 30, 2015 2014 2015 2014 (Dollars and shares in millions, except per share amounts) Net income $ 1,960 $ 3,905 $ 8,488 $ 12,897 Less: Net income attributable to noncontrolling interest — — — (1 ) Net income attributable to Fannie Mae 1,960 3,905 8,488 12,896 Dividends distributed or available for distribution to senior preferred stockholder (1) (2,202 ) (3,999 ) (8,357 ) (13,403 ) Net income (loss) attributable to common stockholders $ (242 ) $ (94 ) $ 131 $ (507 ) Weighted-average common shares outstanding—Basic (2) 5,762 5,762 5,762 5,762 Convertible preferred stock — — 131 — Weighted-average common shares outstanding—Diluted (2) 5,762 5,762 5,893 5,762 Earnings (loss) per share: Basic $ (0.04 ) $ (0.02 ) $ 0.02 $ (0.09 ) Diluted (0.04 ) (0.02 ) 0.02 (0.09 ) __________ (1) Dividends distributed or available for distribution for the three months ended September 30, 2015 and 2014 (relating to the dividend periods for the three months ended December 31, 2015 and 2014) were calculated based on our net worth as of September 30, 2015 and 2014, respectively, less the applicable capital reserve. For the nine months ended September 30, 2015 , we add dividends paid related to the dividend periods for the three months ended September 30, 2015 and June 30, 2015. For the nine months ended September 30, 2014 , we add dividends paid related to the dividend periods for the three months ended September 30, 2014 and June 30, 2014. (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 September 30, 2015 and 2014.

Segment Reporting (Tables)

Segment Reporting (Tables)	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Segment results [Table Text Block]	For the Three Months Ended September 30, 2015 Business Segments Other Activity/Reconciling Items Single-Family Multifamily Capital Markets Consolidated Trusts (1) Eliminations/ Adjustments (2) Total Results (Dollars in millions) Net interest income (loss) $ 66 $ (16 ) $ 1,401 $ 3,901 $ 236 (3) $ 5,588 Benefit for credit losses 1,545 5 — — — 1,550 Net interest income (loss) after benefit for credit losses 1,611 (11 ) 1,401 3,901 236 7,138 Guaranty fee income (expense) (4) 3,145 367 (210 ) (2,024 ) (5) (1,247 ) (5) 31 (5) Investment gains (losses), net (1 ) 5 1,608 (187 ) (1,126 ) (6) 299 Fair value gains (losses), net (4 ) — (2,697 ) 32 80 (7) (2,589 ) Debt extinguishment gains (losses), net — — (25 ) 14 — (11 ) Gains (losses) from partnership investments (8) (12 ) 7 — — — (5 ) Fee and other income (expense) 98 58 83 (80 ) 69 228 Administrative expenses (649 ) (109 ) (194 ) — — (952 ) Foreclosed property income (expense) (516 ) 19 — — — (497 ) TCCA fees (4) (413 ) — — — — (413 ) Other income (expenses) (180 ) 5 24 (93 ) 45 (199 ) Income (loss) before federal income taxes 3,079 341 (10 ) 1,563 (1,943 ) 3,030 Provision for federal income taxes (1,040 ) (17 ) (13 ) — — (1,070 ) Net income (loss) attributable to Fannie Mae $ 2,039 $ 324 $ (23 ) $ 1,563 $ (1,943 ) $ 1,960 For the Nine Months Ended September 30, 2015 Business Segments Other Activity/Reconciling Items Single-Family Multifamily Capital Markets Consolidated Trusts (1) Eliminations/ Adjustments (2) Total Results (Dollars in millions) Net interest income (loss) $ 93 $ (73 ) $ 4,516 $ 11,039 $ 757 (3) $ 16,332 Benefit for credit losses 967 83 — — — 1,050 Net interest income after benefit for credit losses 1,060 10 4,516 11,039 757 17,382 Guaranty fee income (expense) (4) 9,277 1,064 (658 ) (5,929 ) (5) (3,655 ) (5) 99 (5) Investment gains (losses), net (2 ) 29 4,679 (664 ) (2,887 ) (6) 1,155 Fair value gains (losses), net (8 ) — (2,112 ) 37 181 (7) (1,902 ) Debt extinguishment gains (losses), net — — (30 ) 30 — — Gains (losses) from partnership investments (8) (27 ) 262 — — — 235 Fee and other income (expense) 571 193 288 (249 ) 221 1,024 Administrative expenses (1,591 ) (280 ) (493 ) — — (2,364 ) Foreclosed property income (expense) (1,183 ) 31 — — — (1,152 ) TCCA fees (4) (1,192 ) — — — — (1,192 ) Other income (expenses) (669 ) (8 ) 18 (93 ) 105 (647 ) Income before federal income taxes 6,236 1,301 6,208 4,171 (5,278 ) 12,638 Provision for federal income taxes (2,040 ) (128 ) (1,982 ) — — (4,150 ) Net income attributable to Fannie Mae $ 4,196 $ 1,173 $ 4,226 $ 4,171 $ (5,278 ) $ 8,488 For the Three Months Ended September 30, 2014 Business Segments Other Activity/Reconciling Items Single-Family Multifamily Capital Markets Consolidated Trusts (1) Eliminations/ Adjustments (2) Total Results (Dollars in millions) Net interest income (loss) $ 19 $ (22 ) $ 1,845 $ 3,088 $ 254 (3) $ 5,184 Benefit for credit losses 1,029 56 — — — 1,085 Net interest income after benefit for credit losses 1,048 34 1,845 3,088 254 6,269 Guaranty fee income (expense) (4) 2,945 332 (235 ) (1,488 ) (5) (1,502 ) (5) 52 (5) Investment gains, net — 8 1,510 21 (1,368 ) (6) 171 Fair value gains (losses), net (4 ) — (335 ) 13 119 (7) (207 ) Debt extinguishment gains (losses), net — — (3 ) 14 — 11 Gains from partnership investments (8) — 52 — — — 52 Fee and other income (expense) 146 32 579 (71 ) 88 774 Administrative expenses (468 ) (77 ) (161 ) — — (706 ) Foreclosed property income (expense) (281 ) 32 — — — (249 ) TCCA fees (4) (351 ) — — — — (351 ) Other income (expenses) (136 ) 8 (5 ) — 9 (124 ) Income before federal income taxes 2,899 421 3,195 1,577 (2,400 ) 5,692 Provision for federal income taxes (837 ) (37 ) (913 ) — — (1,787 ) Net income attributable to Fannie Mae $ 2,062 $ 384 $ 2,282 $ 1,577 $ (2,400 ) $ 3,905 For the Nine Months Ended September 30, 2014 Business Segments Other Activity/Reconciling Items Single-Family Multifamily Capital Markets Consolidated Trusts (1) Eliminations/ Adjustments (2) Total Results (Dollars in millions) Net interest income (loss) $ (24 ) $ (65 ) $ 5,592 $ 8,525 $ 798 (3) $ 14,826 Benefit for credit losses 3,377 121 — — — 3,498 Net interest income after benefit for credit losses 3,353 56 5,592 8,525 798 18,324 Guaranty fee income (expense) (4) 8,708 960 (722 ) (4,367 ) (5) (4,441 ) (5) 138 (5) Investment gains (losses), net (1 ) 50 4,420 (141 ) (3,579 ) (6) 749 Fair value gains (losses), net (11 ) — (2,770 ) 232 218 (7) (2,331 ) Debt extinguishment gains, net — — 31 18 — 49 Gains from partnership investments (8) — 131 — — 1 132 Fee and other income (expense) 471 87 4,848 (242 ) 262 5,426 Administrative expenses (1,376 ) (225 ) (474 ) — — (2,075 ) Foreclosed property income 154 73 — — — 227 TCCA fees (4) (1,008 ) — — — — (1,008 ) Other expenses (528 ) (5 ) (70 ) — (8 ) (611 ) Income before federal income taxes 9,762 1,127 10,855 4,025 (6,749 ) 19,020 Provision for federal income taxes (2,897 ) (37 ) (3,189 ) — — (6,123 ) Net income 6,865 1,090 7,666 4,025 (6,749 ) 12,897 Less: Net income attributable to noncontrolling interest — — — — (1 ) (1 ) Net income attributable to Fannie Mae $ 6,865 $ 1,090 $ 7,666 $ 4,025 $ (6,750 ) $ 12,896 __________ (1) Represents activity related to the assets and liabilities of consolidated trusts in our condensed consolidated balance sheets. (2) Represents the elimination of intercompany transactions occurring between the three business segments and our consolidated trusts, as well as other adjustments to reconcile to our consolidated results. (3) Represents the amortization expense of cost basis adjustments on securities in the Capital Markets group’s retained mortgage portfolio that on a GAAP basis are eliminated. (4) Reflects the impact of a 10 basis point guaranty fee increase implemented pursuant to the TCCA, the incremental revenue from which must be remitted to Treasury. The resulting revenue is included in guaranty fee income and the expense is recognized as “TCCA fees.” (5) Represents the guaranty fees paid from consolidated trusts to the Single-Family and Multifamily segments. The adjustment to guaranty fee income in the Eliminations/Adjustments column represents the elimination of the amortization of deferred cash fees related to consolidated trusts that were re-established for segment reporting. Total guaranty fee income related to unconsolidated Fannie Mae MBS trusts and other credit enhancement arrangements is included in fee and other income in our condensed consolidated statements of operations and comprehensive income. (6) Primarily represents the removal of realized gains and losses on sales of Fannie Mae MBS classified as available-for-sale securities that are issued by consolidated trusts and in the Capital Markets group’s retained mortgage portfolio. The adjustment also includes the removal of securitization gains (losses) recognized in the Capital Markets segment relating to portfolio securitization transactions that do not qualify for sale accounting under GAAP. (7) Represents the removal of fair value adjustments on consolidated Fannie Mae MBS classified as trading that are in the Capital Markets group’s retained mortgage portfolio. (8) Gains (losses) from partnership investments are included in other expenses in our condensed consolidated statements of operations and comprehensive income.

Equity (Tables)

Equity (Tables)	9 Months Ended
	Sep. 30, 2015
Equity [Abstract]
Schedule of Other Comprehensive Income (Loss) [Table Text Block]	The following table displays the activity in other comprehensive income (“OCI”), net of tax, by major categories. For the Three Months Ended September 30, For the Nine Months Ended September 30, 2015 2014 2015 2014 (Dollars in millions) Net income $ 1,960 $ 3,905 $ 8,488 $ 12,897 Other comprehensive income (loss), net of tax effect: Changes in net unrealized gains on AFS securities (net of tax of $58 and $61, respectively, for the three months ended and net of tax of $89 and $364, respectively, for the nine months ended) (107 ) 113 (164 ) 675 Reclassification adjustment for OTTI recognized in net income (net of tax of $2 for the three months ended and net of tax of $66 and $28, respectively, for the nine months ended) 3 4 121 52 Reclassification adjustment for gains on AFS securities included in net income (net of tax of $32 and $29, respectively, for the three months ended and net of tax of $265 and $133, respectively for the nine months ended) (73 ) (54 ) (505 ) (247 ) Other (1) 430 32 428 32 Total other comprehensive income (loss) 253 95 (120 ) 512 Total comprehensive income $ 2,213 $ 4,000 $ 8,368 $ 13,409 __________ (1) For the three and nine months ended September 30, 2015, includes reclassification adjustment related to the termination of the defined benefit pension plan recognized in “Administrative expenses” and “Provision for federal income taxes” in our condensed consolidated statements of operations and comprehensive income.
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following table displays our accumulated other comprehensive income (“AOCI”) by major categories. As of September 30, December 31, 2015 2014 (Dollars in millions) Net unrealized gains on AFS securities for which we have not recorded OTTI, net of tax $ 551 $ 592 Net unrealized gains on AFS securities for which we have recorded OTTI, net of tax 1,022 1,529 Prior service credit (cost) and actuarial gains (losses), net of amortization, net of tax 39 (358 ) Other gains (losses) 1 (30 ) Accumulated other comprehensive income $ 1,613 $ 1,733 The table below displays changes in AOCI, net of tax. For the Three Months Ended September 30, For the Nine Months Ended September 30, 2015 2014 2015 2014 AFS (1) Other (2) Total AFS (1) Other Total AFS (1) Other (2) Total AFS (1) Other Total (Dollars in millions) Beginning balance $ 1,750 $ (390 ) $ 1,360 $ 2,044 $ (424 ) $ 1,620 $ 2,121 $ (388 ) $ 1,733 $ 1,627 $ (424 ) $ 1,203 OCI before reclassifications (107 ) 6 (101 ) 113 32 145 (164 ) 6 (158 ) 675 32 707 Amounts reclassified from OCI (70 ) 424 354 (50 ) — (50 ) (384 ) 422 38 (195 ) — (195 ) Net OCI (177 ) 430 253 63 32 95 (548 ) 428 (120 ) 480 32 512 Ending balance $ 1,573 $ 40 $ 1,613 $ 2,107 $ (392 ) $ 1,715 $ 1,573 $ 40 $ 1,613 $ 2,107 $ (392 ) $ 1,715 __________ (1) The amounts reclassified from AOCI 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 “Investments gains, net” in our condensed consolidated statements of operations and comprehensive income. (2) The amounts reclassified from AOCI represent activity from our defined benefit pension plans, which is recorded in “Administrative expenses” and “Provision for federal income taxes,” in our condensed consolidated statements of operations and comprehensive income.

Concentrations of Credit Risk C

Concentrations of Credit Risk Concentrations of Credit Risk (Tables)	9 Months Ended
	Sep. 30, 2015
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 September 30 , 2015 (1) December 31, 2014 (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) 1.29 % 0.36 % 1.64 % 1.27 % 0.38 % 1.99 % Percentage of single-family conventional loans (4) 1.48 0.40 1.59 1.47 0.43 1.89
Schedule of Risk Characteristics Guaranty Book of Business [Table Text Block]	As of September 30, 2015 (1) December 31, 2014 (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% 3 % 10.71 % 5 % 10.98 % Geographical distribution: California 20 0.60 20 0.70 Florida 6 3.11 6 4.42 Illinois 4 1.95 4 2.36 New Jersey 4 5.01 4 5.78 New York 5 3.67 5 4.17 All other states 61 1.33 61 1.52 Product distribution: Alt-A 4 6.75 4 7.77 Vintages: 2005 2 5.66 3 6.18 2006 3 8.58 3 9.61 2007 4 9.80 4 10.79 2008 2 5.86 2 6.27 All other vintages 89 0.78 88 0.88 __________ (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 September 30, 2015 and December 31, 2014 . (2) Consists of single-family conventional loans that were 90 days or more past due or in the foreclosure process as of September 30, 2015 and December 31, 2014 . (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 September 30, 2015 (1)(2) December 31, 2014 (1)(2) 30 Days Delinquent Seriously Delinquent (3) 30 Days Delinquent Seriously Delinquent (3) Percentage of multifamily guaranty book of business 0.04 % 0.05 % 0.04 % 0.05 %
Schedule of Risk Characteristics Guaranty Book of Business [Table Text Block]	As of September 30, 2015 (1) December 31, 2014 (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% 3 % 0.03 % 3 % 0.31 % Less than or equal to 80% 97 0.06 97 0.04 Current debt service coverage ratio less than 1.0 (5) 2 0.87 3 0.83 __________ (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 September 30, 2015 and December 31, 2014 , 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)	9 Months Ended
	Sep. 30, 2015
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 September 30, 2015 Net Amount Presented in the Condensed Consolidated Balance Sheets Amounts Not Offset in the 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 $ 4,494 $ (4,487 ) $ 7 $ — $ — $ 7 Cleared risk management derivatives 1,124 70 1,194 — — 1,194 Mortgage commitment derivatives 384 — 384 (189 ) (2 ) 193 Total derivative assets 6,002 (4,417 ) 1,585 (4 ) (189 ) (2 ) 1,394 Securities purchased under agreements to resell or similar arrangements (5) 42,100 — 42,100 — (42,100 ) — Total assets $ 48,102 $ (4,417 ) $ 43,685 $ (189 ) $ (42,102 ) $ 1,394 Liabilities: OTC risk management derivatives $ (7,417 ) $ 7,082 $ (335 ) $ — $ — $ (335 ) Cleared risk management derivatives (3,554 ) 3,553 (1 ) — 1 — Mortgage commitment derivatives (567 ) — (567 ) 189 6 (372 ) Total derivative liabilities (11,538 ) 10,635 (903 ) (4 ) 189 7 (707 ) Securities sold under agreements to repurchase or similar arrangements (118 ) — (118 ) — 118 — Total liabilities $ (11,656 ) $ 10,635 $ (1,021 ) $ 189 $ 125 $ (707 ) As of December 31, 2014 Net Amount Presented in the Condensed Consolidated Balance Sheets Amounts Not Offset in the 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 $ 5,461 $ (5,428 ) $ 33 $ — $ (33 ) $ — Cleared risk management derivatives 927 242 1,169 — — 1,169 Mortgage commitment derivatives 255 — 255 (116 ) (7 ) 132 Total derivative assets 6,643 (5,186 ) 1,457 (4 ) (116 ) (40 ) 1,301 Securities purchased under agreements to resell or similar arrangements (5) 47,550 — 47,550 — (47,550 ) — Total assets $ 54,193 $ (5,186 ) $ 49,007 $ (116 ) $ (47,590 ) $ 1,301 Liabilities: OTC risk management derivatives $ (7,836 ) $ 7,567 $ (269 ) $ — $ — $ (269 ) Cleared risk management derivatives (2,627 ) 2,627 — — — — Mortgage commitment derivatives (344 ) — (344 ) 116 — (228 ) Total derivative liabilities (10,807 ) 10,194 (613 ) (4 ) 116 — (497 ) Securities sold under agreements to repurchase or similar arrangements (50 ) — (50 ) — 50 — Total liabilities $ (10,857 ) $ 10,194 $ (663 ) $ 116 $ 50 $ (497 ) __________ (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 collateral received that has neither been recognized nor offset in our condensed consolidated balance sheets as well as collateral posted that has neither been derecognized nor 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 accepted for OTC risk management derivatives was $51 million as of December 31, 2014 . The fair value of non-cash collateral accepted for securities purchased under agreements to resell or similar arrangements was $42.2 billion and $47.6 billion , of which $37.9 billion and $41.9 billion could be sold or repledged as of September 30, 2015 and December 31, 2014 , respectively. None of the underlying collateral was sold or repledged as of September 30, 2015 or December 31, 2014 . The fair value of non-cash collateral we pledged for securities sold under agreements to repurchase was $ 118 million and $50 million as of September 30, 2015 and December 31, 2014 , respectively, which the counterparty was permitted to sell or repledge. The fair value of non-cash collateral we pledged for cleared risk management derivatives was $ 136 million as of September 30, 2015, which the counterparty was permitted to sell or repledge. (4) Excludes derivative assets of $25 million and $28 million as of September 30, 2015 and December 31, 2014 , respectively, and derivative liabilities of $1 million as of September 30, 2015 and December 31, 2014 , recognized in our condensed consolidated balance sheets that are not subject to enforceable master netting arrangements. (5) Includes $15.5 billion and $16.6 billion of securities purchased under agreements to resell or similar arrangements classified as “Cash and cash equivalents” in our condensed consolidated balance sheets as of September 30, 2015 and December 31, 2014 , respectively.

Fair Value (Tables)

Fair Value (Tables)	9 Months Ended
	Sep. 30, 2015
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 September 30, 2015 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 $ — $ 5,097 $ — $ — $ 5,097 Freddie Mac — 1,474 — — 1,474 Ginnie Mae — 353 — — 353 Alt-A private-label securities — 136 315 — 451 Subprime private-label securities — — 696 — 696 CMBS — 2,398 — — 2,398 Mortgage revenue bonds — — 579 — 579 Non-mortgage-related securities: U.S. Treasury securities 26,961 — — — 26,961 Total trading securities 26,961 9,458 1,590 — 38,009 Available-for-sale securities: Mortgage-related securities: Fannie Mae — 4,282 — — 4,282 Freddie Mac — 4,595 4 — 4,599 Ginnie Mae — 413 — — 413 Alt-A private-label securities — 1,855 1,494 — 3,349 Subprime private-label securities — — 3,677 — 3,677 CMBS — 1,309 — — 1,309 Mortgage revenue bonds — — 2,933 — 2,933 Other — 1 1,444 — 1,445 Total available-for-sale securities — 12,455 9,552 — 22,007 Mortgage loans — 13,105 1,500 — 14,605 Other assets: Risk management derivatives: Swaps — 5,417 158 — 5,575 Swaptions — 39 4 — 43 Other — — 25 — 25 Netting adjustment — — — (4,417 ) (4,417 ) Mortgage commitment derivatives — 374 10 — 384 Total other assets — 5,830 197 (4,417 ) 1,610 Total assets at fair value $ 26,961 $ 40,848 $ 12,839 $ (4,417 ) $ 76,231 Fair Value Measurements as of September 30, 2015 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 $ — $ 9,606 $ 369 $ — $ 9,975 Total of Fannie Mae — 9,606 369 — 9,975 Of consolidated trusts — 22,572 571 — 23,143 Total long-term debt — 32,178 940 — 33,118 Other liabilities: Risk management derivatives: Swaps — 10,531 133 — 10,664 Swaptions — 307 — — 307 Other — — 1 — 1 Netting adjustment — — — (10,635 ) (10,635 ) Mortgage commitment derivatives — 564 3 — 567 Total other liabilities — 11,402 137 (10,635 ) 904 Total liabilities at fair value $ — $ 43,580 $ 1,077 $ (10,635 ) $ 34,022 Fair Value Measurements as of December 31, 2014 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 $ — $ 4,635 $ 305 $ — $ 4,940 Freddie Mac — 1,369 — — 1,369 Ginnie Mae — 166 — — 166 Alt-A private-label securities — 323 597 — 920 Subprime private-label securities — — 1,307 — 1,307 CMBS — 2,515 — — 2,515 Mortgage revenue bonds — — 722 — 722 Other — — 99 — 99 Non-mortgage-related securities: U.S. Treasury securities 19,466 — — — 19,466 Total trading securities 19,466 9,008 3,030 — 31,504 Available-for-sale securities: Mortgage-related securities: Fannie Mae — 5,639 — — 5,639 Freddie Mac — 5,522 6 — 5,528 Ginnie Mae — 476 — — 476 Alt-A private-label securities — 2,538 3,140 — 5,678 Subprime private-label securities — — 5,240 — 5,240 CMBS — 1,397 — — 1,397 Mortgage revenue bonds — — 4,023 — 4,023 Other — 2 2,671 — 2,673 Total available-for-sale securities — 15,574 15,080 — 30,654 Mortgage loans — 13,796 1,833 — 15,629 Other assets: Risk management derivatives: Swaps — 6,085 150 — 6,235 Swaptions — 153 — — 153 Other — — 28 — 28 Netting adjustment — — — (5,186 ) (5,186 ) Mortgage commitment derivatives — 251 4 — 255 Total other assets — 6,489 182 (5,186 ) 1,485 Total assets at fair value $ 19,466 $ 44,867 $ 20,125 $ (5,186 ) $ 79,272 Fair Value Measurements as of December 31, 2014 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 $ — $ 6,040 $ 363 $ — $ 6,403 Total of Fannie Mae — 6,040 363 — 6,403 Of consolidated trusts — 18,956 527 — 19,483 Total long-term debt — 24,996 890 — 25,886 Other liabilities: Risk management derivatives: Swaps — 9,339 133 — 9,472 Swaptions — 991 — — 991 Other — — 1 — 1 Netting adjustment — — — (10,194 ) (10,194 ) Mortgage commitment derivatives — 341 3 — 344 Total other liabilities — 10,671 137 (10,194 ) 614 Total liabilities at fair value $ — $ 35,667 $ 1,027 $ (10,194 ) $ 26,500 __________ (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 both 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 September 30, 2015 Total Gains or (Losses) (Realized/Unrealized) Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of September 30, 2015 (5)(6) Balance, June 30, 2015 Included in Net Income Included in Other Comprehensive Income (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 (4) Transfers into Level 3 (4) Balance, September 30, 2015 (Dollars in millions) Trading securities: Mortgage-related: Alt-A private-label securities $ 325 $ (3 ) $ — $ — $ — $ — $ (7 ) $ — $ — $ 315 $ (3 ) Subprime private-label securities 718 (5 ) — — — — (17 ) — — 696 (5 ) Mortgage revenue bonds 602 (19 ) — — — — (4 ) — — 579 (19 ) Total trading securities $ 1,645 $ (27 ) (6)(7) $ — $ — $ — $ — $ (28 ) $ — $ — $ 1,590 $ (27 ) Available-for-sale securities: Mortgage-related: Fannie Mae $ 129 $ — $ — $ — $ (122 ) $ — $ (8 ) $ — $ 1 $ — $ — Freddie Mac 4 — — — — — — (1 ) 1 4 — Alt-A private-label securities 1,654 2 (8 ) — — — (178 ) — 24 1,494 — Subprime private-label securities 3,837 33 (45 ) — — — (148 ) — — 3,677 — Mortgage revenue bonds 3,171 4 (29 ) — (8 ) — (205 ) — — 2,933 — Other 2,158 73 (95 ) — (644 ) — (48 ) — — 1,444 — Total available-for-sale securities $ 10,953 $ 112 (7)(8) $ (177 ) $ — $ (774 ) $ — $ (587 ) $ (1 ) $ 26 $ 9,552 $ — Mortgage loans $ 1,595 $ 9 (6)(7) $ — $ — $ — $ — $ (97 ) $ (77 ) $ 70 $ 1,500 $ (24 ) Net derivatives 4 79 (6) — — — — (32 ) — 9 60 28 Long-term debt: Of Fannie Mae: Senior floating $ (346 ) $ (23 ) $ — $ — $ — $ — $ — $ — $ — $ (369 ) $ (23 ) Of consolidated trusts (493 ) — — — — (64 ) 18 33 (65 ) (571 ) — Total long-term debt $ (839 ) $ (23 ) (6) $ — $ — $ — $ (64 ) $ 18 $ 33 $ (65 ) $ (940 ) $ (23 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Nine Months Ended September 30, 2015 Total Gains or (Losses) (Realized/Unrealized) Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of September 30, 2015 (5)(6) Balance, December 31, 2014 Included in Net Income Included in Other Comprehensive Income (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 (4) Transfers into Level 3 (4) Balance, September 30, 2015 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 305 $ (27 ) $ — $ — $ (2 ) $ — $ — $ (278 ) $ 2 $ — $ — Alt-A private-label securities 597 41 — — (267 ) — (40 ) (44 ) 28 315 (3 ) Subprime private-label securities 1,307 38 — — (580 ) — (69 ) — — 696 (2 ) Mortgage revenue bonds 722 (17 ) — — (118 ) — (8 ) — — 579 (17 ) Other 99 4 — — (100 ) — (3 ) — — — — Total trading securities $ 3,030 $ 39 (6)(7) $ — $ — $ (1,067 ) $ — $ (120 ) $ (322 ) $ 30 $ 1,590 $ (22 ) Available-for-sale securities: Mortgage-related: Fannie Mae $ — $ — $ — $ 421 $ (425 ) $ — $ (8 ) $ — $ 12 $ — $ — Freddie Mac 6 — — — — — (1 ) (2 ) 1 4 — Alt-A private-label securities 3,140 174 (124 ) — (1,108 ) — (387 ) (538 ) 337 1,494 — Subprime private-label securities 5,240 478 (277 ) — (1,325 ) — (439 ) — — 3,677 — Mortgage revenue bonds 4,023 44 (56 ) — (324 ) — (754 ) — — 2,933 — Other 2,671 (20 ) (10 ) — (1,012 ) — (185 ) — — 1,444 — Total available-for-sale securities $ 15,080 $ 676 (7)(8) $ (467 ) $ 421 $ (4,194 ) $ — $ (1,774 ) $ (540 ) $ 350 $ 9,552 $ — Mortgage loans $ 1,833 $ 47 (6)(7) $ — $ 5 $ — $ — $ (273 ) $ (331 ) $ 219 $ 1,500 $ (17 ) Net derivatives 45 (20 ) (6) — — — — 26 — 9 60 23 Long-term debt: Of Fannie Mae: Senior floating $ (363 ) $ (6 ) $ — $ — $ — $ — $ — $ — $ — $ (369 ) $ (6 ) Of consolidated trusts (527 ) (8 ) — — — (64 ) 43 142 (157 ) (571 ) 11 Total long-term debt $ (890 ) $ (14 ) (6) $ — $ — $ — $ (64 ) $ 43 $ 142 $ (157 ) $ (940 ) $ 5 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Three Months Ended September 30, 2014 Total Gains or (Losses) (Realized/Unrealized) Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of September 30, 2014 (5)(6) Balance, June 30, 2014 Included in Net Income Included in Other Comprehensive Income (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 (4) Transfers into Level 3 (4) Balance, September 30, 2014 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ — $ — $ — $ — $ — $ — $ — $ — $ 325 $ 325 $ — Alt-A private-label securities 643 2 — — — — (21 ) (16 ) 87 695 3 Subprime private-label securities 1,282 66 — — — — (32 ) — — 1,316 66 Mortgage revenue bonds 643 53 — — — — (3 ) — — 693 46 Other 101 1 — — — — (3 ) — — 99 1 Total trading securities $ 2,669 $ 122 (6)(7) $ — $ — $ — $ — $ (59 ) $ (16 ) $ 412 $ 3,128 $ 116 Available-for-sale securities: Mortgage-related: Fannie Mae $ 2 $ — $ — $ — $ — $ — $ — $ (2 ) $ — $ — $ — Freddie Mac 9 — — — — — (1 ) (2 ) — 6 — Alt-A private-label securities 3,717 15 (60 ) — — — (111 ) (333 ) 268 3,496 — Subprime private-label securities 5,705 87 89 — (317 ) — (178 ) — — 5,386 — Mortgage revenue bonds 4,560 (4 ) 200 — (12 ) — (478 ) — — 4,266 — Other 2,817 11 (3 ) — — — (82 ) — — 2,743 — Total available-for-sale securities $ 16,810 $ 109 (7)(8) $ 226 $ — $ (329 ) $ — $ (850 ) $ (337 ) $ 268 $ 15,897 $ — Mortgage loans $ 2,531 $ 116 (6)(7) $ — $ 3 $ — $ — $ (93 ) $ (750 ) $ 64 $ 1,871 $ (13 ) Net derivatives 20 (25 ) (6) — — — — (9 ) — 5 (9 ) 41 (9 ) Long-term debt: Of Fannie Mae: Senior floating $ (325 ) $ (10 ) $ — $ — $ — $ — $ (1 ) $ — $ — $ (336 ) $ (11 ) Of consolidated trusts (498 ) (14 ) — — — — 16 34 (26 ) (488 ) (14 ) Total long-term debt $ (823 ) $ (24 ) (6) $ — $ — $ — $ — $ 15 $ 34 $ (26 ) $ (824 ) $ (25 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Nine Months Ended September 30, 2014 Total Gains or (Losses) (Realized/Unrealized) Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of September 30, 2014 (5)(6) Balance, December 31, 2013 Included in Net Income Included in Other Comprehensive Income (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 (4) Transfers into Level 3 (4) Balance, September 30, 2014 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 42 $ (1 ) $ — $ — $ — $ — $ (2 ) $ (39 ) $ 325 $ 325 $ — Freddie Mac 2 — — — — — — (2 ) — — — Alt-A private-label securities 618 105 — — (23 ) — (59 ) (159 ) 213 695 100 Subprime private-label securities 1,448 245 — — (241 ) — (136 ) — — 1,316 209 Mortgage revenue bonds 565 137 — — — — (9 ) — — 693 130 Other 99 10 — — — — (10 ) — — 99 10 Total trading securities $ 2,774 $ 496 (6)(7) $ — $ — $ (264 ) $ — $ (216 ) $ (200 ) $ 538 $ 3,128 $ 449 Available-for-sale securities: Mortgage-related: Fannie Mae $ 7 $ — $ — $ — $ — $ — $ (1 ) $ (8 ) $ 2 $ — $ — Freddie Mac 8 — — — — — (1 ) (2 ) 1 6 — Alt-A private-label securities 3,791 131 (11 ) — (320 ) — (310 ) (1,207 ) 1,422 3,496 — Subprime private-label securities 7,068 388 270 — (1,666 ) — (674 ) — — 5,386 — Mortgage revenue bonds 5,253 (31 ) 480 — (70 ) — (1,366 ) — — 4,266 — Other 2,885 17 92 — — — (251 ) — — 2,743 — Total available-for-sale securities $ 19,012 $ 505 (7)(8) $ 831 $ — $ (2,056 ) $ — $ (2,603 ) $ (1,217 ) $ 1,425 $ 15,897 $ — Mortgage loans $ 2,704 $ 243 (6)(7) $ — $ 34 $ — $ — $ (259 ) $ (1,063 ) $ 212 $ 1,871 $ 49 Net derivatives (40 ) 52 (6) — — — — (25 ) (1 ) 5 (9 ) 14 Long-term debt: Of Fannie Mae: Senior floating $ (955 ) $ (115 ) $ — $ — $ — $ (750 ) $ 19 $ 1,465 $ — $ (336 ) $ (70 ) Of consolidated trusts (518 ) (48 ) — — — (1 ) 51 100 (72 ) (488 ) (45 ) Total long-term debt $ (1,473 ) $ (163 ) (6) $ — $ — $ — $ (751 ) $ 70 $ 1,565 $ (72 ) $ (824 ) $ (115 ) __________ (1) Gains (losses) included in other comprehensive income are included in “Changes in unrealized gains on AFS securities, net of reclassification adjustments and taxes” in the 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 out of Level 3 consisted primarily of private-label mortgage-related securities backed by Alt-A loans and credit risk sharing securities issued under our CAS series. Prices for these securities were obtained from multiple third-party vendors or dealers. Transfers out of Level 3 also occurred for mortgage loans for which unobservable inputs used in valuations became less significant. Transfers into Level 3 consisted primarily of private-label mortgage-related securities backed by Alt-A loans. Prices for these securities are based on inputs from a single source or inputs that were not readily observable. (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 September 30, 2015 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: Alt-A private-label securities (2) $ 64 Consensus Default Rate (%) 1.6 1.6 Prepayment Speed (%) 3.7 3.7 Severity (%) 61.7 61.7 Spreads (bps) 266.1 266.1 251 Discounted Cash Flow Default Rate (%) 1.5 - 3.0 2.7 Prepayment Speed (%) 4.0 4.0 Severity (%) 55.0 - 95.0 88.1 Spreads (bps) 222.5 - 230.4 229.0 Total Alt-A private-label securities 315 Subprime private-label securities (2) 479 Consensus Default Rate (%) 4.0 - 10.3 6.5 Prepayment Speed (%) 1.0 - 4.6 2.3 Severity (%) 41.8 - 95.0 75.5 Spreads (bps) 275.0 - 280.0 275.4 169 Discounted Cash Flow Default Rate (%) 4.0 - 8.0 5.0 Prepayment Speed (%) 2.0 - 3.3 2.4 Severity (%) 60.0 - 78.0 65.2 Spreads (bps) 203.0 - 300.0 225.7 48 Other Total subprime private-label securities 696 Mortgage revenue bonds 563 Discounted Cash Flow Spreads (bps) 24.5 - 371.8 274.8 16 Other Total mortgage revenue bonds 579 Total trading securities $ 1,590 Fair Value Measurements as of September 30, 2015 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Available-for-sale securities: Mortgage-related securities: Agency (3) $ 4 Other Alt-A private-label securities (2) 598 Consensus Default Rate (%) 0.4 - 12.2 4.3 Prepayment Speed (%) 0.2 - 31.8 14.5 Severity (%) 6.8 - 95.0 66.5 Spreads (bps) 197.0 - 245.0 242.7 545 Consensus 313 Discounted Cash Flow Default Rate (%) 4.0 - 7.0 4.5 Prepayment Speed (%) 3.0 - 10.0 5.0 Severity (%) 50.0 - 85.0 63.5 Spreads (bps) 201.6 - 481.0 289.2 38 Other Total Alt-A private-label securities 1,494 Subprime private-label securities (2) 2,365 Consensus Default Rate (%) 0.5 - 19.3 7.7 Prepayment Speed (%) 0.3 - 13.2 3.4 Severity (%) 14.5 - 95.0 78.5 Spreads (bps) 245.0 - 280.0 273.7 774 Consensus 265 Discounted Cash Flow Default Rate (%) 5.6 - 12.0 7.8 Prepayment Speed (%) 1.0 - 4.0 1.9 Severity (%) 59.0 - 95.0 80.4 Spreads (bps) 169.4 - 315.0 225.4 273 Other Total subprime private-label securities 3,677 Mortgage revenue bonds 1,126 Single Vendor Spreads (bps) 7.0 - 347.9 62.8 1,607 Discounted Cash Flow Spreads (bps) 7.0 - 407.9 275.5 200 Other Total mortgage revenue bonds 2,933 Other 737 Consensus Default Rate (%) 0.0 - 4.6 3.4 Prepayment Speed (%) 2.5 - 17.4 4.5 Severity (%) 3.1 - 95.0 67.1 Spreads (bps) 195.0 - 466.3 334.1 550 Discounted Cash Flow Default Rate (%) 0.0 - 4.9 0.2 Prepayment Speed (%) 0.0 - 2.0 0.1 Severity (%) 25.0 - 95.0 90.6 Spreads (bps) 245.0 - 350.0 330.3 157 Other Total other 1,444 Total available-for-sale securities $ 9,552 Fair Value Measurements as of September 30, 2015 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Mortgage loans: Single-family $ 107 Build-Up Default Rate (%) 0.0 - 98.8 35.7 Prepayment Speed (%) 3.0 - 100.0 10.4 Severity (%) 0.0 - 100.0 38.5 667 Build-Up 236 Consensus 258 Consensus Default Rate (%) 0.0 - 7.6 3.3 Prepayment Speed (%) 3.2 - 30.3 5.9 Severity (%) 20.0 - 95.0 78.8 Spreads (bps) 243.4 - 278.0 253.5 71 Other Total single-family 1,339 Multifamily 161 Build-Up Spreads (bps) 61.0 - 334.2 161.1 Total mortgage loans $ 1,500 Net derivatives $ (115 ) Internal Model 162 Dealer Mark 13 Other Total net derivatives $ 60 Long-term debt: Of Fannie Mae: Senior floating $ (369 ) Discounted Cash Flow Of consolidated trusts (4) (127 ) Consensus (194 ) Consensus Default Rate (%) 0.0 - 4.0 3.1 Prepayment Speed (%) 3.5 - 30.3 5.4 Severity (%) 20.0 - 95.0 78.0 Spreads (bps) 243.4 - 260.0 254.8 (250 ) Other Total of consolidated trusts (571 ) Total long-term debt $ (940 ) Fair Value Measurements as of December 31, 2014 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 (3)(4) $ 153 Single Vendor Prepayment Speed (%) 100.0 100.0 Spreads (bps) 256.5 - 350.8 293.4 130 Consensus Prepayment Speed (%) 100.0 100.0 Spreads (bps) 184.6 - 219.5 197.5 22 Other Total Agency 305 Alt-A private-label securities (2) 290 Single Vendor Default Rate (%) 8.3 - 9.1 8.5 Prepayment Speed (%) 2.9 - 3.2 3.1 Severity (%) 79.5 - 95.0 90.4 Spreads (bps) 267.2 - 308.2 279.4 66 Consensus Default Rate (%) 5.4 5.4 Prepayment Speed (%) 7.0 7.0 Severity (%) 48.8 48.8 Spreads (bps) 264.8 264.8 151 Consensus 90 Other Total Alt-A private-label securities 597 Subprime private-label securities (2) 422 Consensus Default Rate (%) 3.5 - 11.8 7.2 Prepayment Speed (%) 1.4 - 5.2 2.8 Severity (%) 72.1 - 95.0 85.9 Spreads (bps) 265.0 265.0 549 Consensus 290 Discounted Cash Flow Default Rate (%) 4.3 - 6.2 5.2 Prepayment Speed (%) 2.3 - 4.2 3.3 Severity (%) 62.2 - 95.0 73.8 Spreads (bps) 265.0 - 382.1 283.7 46 Other Total subprime private-label securities 1,307 Mortgage revenue bonds 161 Dealer Mark Spreads (bps) 288.1 288.1 540 Discounted Cash Flow Spreads (bps) 6.0 - 318.0 263.0 21 Other Total mortgage revenue bonds 722 Other 99 Dealer Mark Total trading securities $ 3,030 Fair Value Measurements as of December 31, 2014 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Available-for-sale securities: Mortgage-related securities: Agency (3) $ 6 Other Alt-A private-label securities (2) 322 Single Vendor Default Rate (%) 0.2 - 13.1 4.6 Prepayment Speed (%) 0.2 - 20.5 8.2 Severity (%) 27.8 - 89.7 61.0 Spreads (bps) 190.0 - 315.0 264.9 493 Single Vendor 1,187 Consensus Default Rate (%) 0.4 - 31.2 5.1 Prepayment Speed (%) 0.1 - 48.9 11.0 Severity (%) 0.2 - 95.0 59.6 Spreads (bps) 183.8 - 240.0 236.7 691 Consensus 403 Discounted Cash Flow Default Rate (%) 5.0 - 11.5 7.0 Prepayment Speed (%) 0.5 - 8.4 3.4 Severity (%) 35.1 - 92.4 54.2 Spreads (bps) 188.0 - 340.0 243.4 44 Other Total Alt-A private-label securities 3,140 Subprime private-label securities (2) 383 Single Vendor Default Rate (%) 2.1 - 8.3 5.5 Prepayment Speed (%) 1.5 - 3.3 2.1 Severity (%) 65.4 - 95.0 78.5 Spreads (bps) 215.0 - 262.0 230.0 2,722 Consensus Default Rate (%) 1.5 - 37.4 6.3 Prepayment Speed (%) 0.1 - 17.7 2.6 Severity (%) 1.5 - 95.0 84.4 Spreads (bps) 155.0 - 265.0 220.0 1,755 Consensus 317 Discounted Cash Flow Default Rate (%) 3.0 - 12.3 7.0 Prepayment Speed (%) 1.1 - 9.0 4.1 Severity (%) 28.9 - 91.8 81.2 Spreads (bps) 155.0 - 895.0 250.5 63 Other Total subprime private-label securities 5,240 Mortgage revenue bonds 1,504 Single Vendor Spreads (bps) (11.5 ) - 361.5 52.7 418 Single Vendor 510 Dealer Mark Spreads (bps) 222.8 - 322.1 265.9 1,581 Discounted Cash Flow Spreads (bps) (11.5 ) - 620.2 251.4 10 Other Total mortgage revenue bonds 4,023 Other 337 Single Vendor Default Rate (%) 1.7 - 5.0 4.4 Prepayment Speed (%) 3.0 - 9.3 3.8 Severity (%) 4.0 - 94.6 69.6 Spreads (bps) 263.1 - 427.2 291.5 720 Consensus Default Rate (%) 0.1 - 6.6 3.9 Prepayment Speed (%) 3.0 - 30.4 4.8 Severity (%) 0.4 - 95.0 62.4 Spreads (bps) 215.0 - 481.4 320.6 1,215 Dealer Mark 399 Other Total other 2,671 Total available-for-sale securities $ 15,080 Fair Value Measurements as of December 31, 2014 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Mortgage loans: Single-family $ 934 Build-Up Default Rate (%) 0.0 - 99.0 14.9 Prepayment Speed (%) 3.6 - 99.8 16.3 Severity (%) 3.4 - 100.0 23.7 279 Consensus 402 Discounted Cash Flow Default Rate (%) 2.7 - 13.1 5.5 Prepayment Speed (%) 0.1 - 13.5 7.5 Severity (%) 35.5 - 95.0 61.3 Spreads (bps) 155.0 - 665.0 227.4 39 Other Total single-family 1,654 Multifamily 179 Build-Up Spreads (bps) 59.0 - 323.4 137.3 Total mortgage loans $ 1,833 Net derivatives $ (107 ) Internal Model 150 Dealer Mark 2 Other Total net derivatives $ 45 Long-term debt: Of Fannie Mae: Senior floating $ (363 ) Discounted Cash Flow Of consolidated trusts (4) (219 ) Consensus (205 ) Discounted Cash Flow Default Rate (%) 2.7 - 11.9 4.0 Prepayment Speed (%) 0.1 - 100.0 33.4 Severity (%) 35.5 - 95.0 54.6 Spreads (bps) 88.0 - 665.0 249.4 (103 ) Other Total of consolidated trusts (527 ) Total long-term debt $ (890 ) _________ (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. (2) Default Rate as disclosed represents the estimated beginning annualized rate of default and is used as a basis to forecast the future default rates that serve as an input for valuation. (3) Includes Fannie Mae and Freddie Mac securities. (4) Includes instruments for which the prepayment speed as disclosed represents the estimated annualized rate of prepayment after all prepayment penalty provisions have expired and also instruments for which prepayment speed as disclosed represents the estimated rate of prepayment over the remaining life of the instrument.
Level 3 Assets Measured on Nonrecurring Basis [Table Text Block]	. 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 (Level 3) as of Valuation Techniques September 30, 2015 December 31, 2014 (Dollars in millions) Nonrecurring fair value measurements: Mortgage loans held for sale, at lower of cost or fair value Consensus $ 2,251 $ 110 Single Vendor 431 — Other 2 — Total mortgage loans held for sale, at lower of cost or fair value 2,684 110 Single-family mortgage loans held for investment, at amortized cost Internal Model 8,585 16,654 Other — 60 Total single-family mortgage loans held for investment, at amortized cost 8,585 16,714 Multifamily mortgage loans held for investment, at amortized cost Broker Price Opinions 90 45 Asset Manager Estimate 289 580 Other 7 — Total multifamily mortgage loans held for investment, at amortized cost 386 625 Acquired property, net: Single-family Accepted Offers 620 864 Appraisals 865 1,509 Walk Forwards 637 1,173 Internal Model 970 1,045 Other 122 191 Total single-family 3,214 4,782 Multifamily Broker Price Opinions 31 127 Other 2 13 Total multifamily 33 140 Other assets Other 27 45 Total nonrecurring assets at fair value $ 14,929 $ 22,416
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 certain financial instruments, such as plan obligations for pension and postretirement health care benefits, employee stock option and stock purchase plans, and also excludes all non-financial instruments. As a result, 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 September 30, 2015 Carrying Quoted Price 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 $ 50,196 $ 34,696 $ 15,500 $ — $ — $ 50,196 Federal funds sold and securities purchased under agreements to resell or similar arrangements 26,600 — 26,600 — — 26,600 Trading securities 38,009 26,961 9,458 1,590 — 38,009 Available-for-sale securities 22,007 — 12,455 9,552 — 22,007 Mortgage loans held for sale 3,716 — 178 3,796 3,974 Mortgage loans held for investment, net of allowance for loan losses: Of Fannie Mae 213,639 — 26,358 201,369 — 227,727 Of consolidated trusts 2,803,101 — 2,675,444 184,922 — 2,860,366 Mortgage loans held for investment 3,016,740 — 2,701,802 386,291 — 3,088,093 Advances to lenders 5,253 — 4,829 412 — 5,241 Derivative assets at fair value 1,610 — 5,830 197 (4,417 ) 1,610 Guaranty assets and buy-ups 189 — — 527 — 527 Total financial assets $ 3,164,320 $ 61,657 $ 2,776,652 $ 402,365 $ (4,417 ) $ 3,236,257 Financial liabilities: Federal funds purchased and securities sold under agreements to repurchase $ 118 $ — $ 118 $ — $ — $ 118 Short-term debt: Of Fannie Mae 95,427 — 95,458 — — 95,458 Of consolidated trusts 1,391 — — 1,391 — 1,391 Long-term debt: Of Fannie Mae 322,031 — 334,007 931 — 334,938 Of consolidated trusts 2,787,396 — 2,827,733 26,613 — 2,854,346 Derivative liabilities at fair value 904 — 11,402 137 (10,635 ) 904 Guaranty obligations 338 — — 1,342 — 1,342 Total financial liabilities $ 3,207,605 $ — $ 3,268,718 $ 30,414 $ (10,635 ) $ 3,288,497 As of December 31, 2014 Carrying Quoted Price 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 $ 54,565 $ 37,965 $ 16,600 $ — $ — $ 54,565 Federal funds sold and securities purchased under agreements to resell or similar arrangements 30,950 — 30,950 — — 30,950 Trading securities 31,504 19,466 9,008 3,030 — 31,504 Available-for-sale securities 30,654 — 15,574 15,080 — 30,654 Mortgage loans held for sale 331 — 169 169 — 338 Mortgage loans held for investment, net of allowance for loan losses: Of Fannie Mae 239,243 — 29,896 217,064 — 246,960 Of consolidated trusts 2,779,920 — 2,657,863 183,263 — 2,841,126 Mortgage loans held for investment 3,019,163 — 2,687,759 400,327 — 3,088,086 Advances to lenders 5,559 — 5,079 470 — 5,549 Derivative assets at fair value 1,485 — 6,489 182 (5,186 ) 1,485 Guaranty assets and buy-ups 210 — — 616 — 616 Total financial assets $ 3,174,421 $ 57,431 $ 2,771,628 $ 419,874 $ (5,186 ) $ 3,243,747 Financial liabilities: Federal funds purchased and securities sold under agreements to repurchase $ 50 $ — $ 50 $ — $ — $ 50 Short-term debt: Of Fannie Mae 105,012 — 105,022 — — 105,022 Of consolidated trusts 1,560 — — 1,560 — 1,560 Long-term debt: Of Fannie Mae 355,431 — 367,703 982 — 368,685 Of consolidated trusts 2,760,152 — 2,815,843 19,334 — 2,835,177 Derivative liabilities at fair value 614 — 10,671 137 (10,194 ) 614 Guaranty obligations 382 — — 1,579 — 1,579 Total financial liabilities $ 3,223,201 $ — $ 3,299,289 $ 23,592 $ (10,194 ) $ 3,312,687
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 September 30, 2015 December 31, 2014 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 $ 14,605 $ 9,975 $ 23,143 $ 15,629 $ 6,403 $ 19,483 Unpaid principal balance 14,019 10,104 21,038 15,001 6,512 17,810 __________ (1) Includes nonaccrual loans with a fair value of $241 million and $240 million as of September 30, 2015 and December 31, 2014 , respectively. The difference between unpaid principal balance and the fair value of these nonaccrual loans as of September 30, 2015 and December 31, 2014 was $60 million and $75 million , respectively. Includes loans that are 90 days or more past due with a fair value of $269 million and $271 million as of September 30, 2015 and December 31, 2014 , respectively. The difference between unpaid principal balance and the fair value of these 90 or more days past due loans as of September 30, 2015 and December 31, 2014 was $52 million and $78 million , respectively. 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 September 30, 2015 2014 Loans Long-Term Debt Total Gains (Losses) Loans Long-Term Debt Total Gains (Losses) (Dollars in millions) Changes in instrument-specific credit risk $ 73 $ 150 $ 223 $ 67 $ 187 $ 254 Other changes in fair value (15 ) (81 ) (96 ) (33 ) (27 ) (60 ) Fair value gains, net $ 58 $ 69 $ 127 $ 34 $ 160 $ 194 For the Nine Months Ended September 30, 2015 2014 Loans Long-Term Debt Total Gains (Losses) Loans Long-Term Debt Total Gains (Losses) (Dollars in millions) Changes in instrument-specific credit risk $ 110 $ 45 $ 155 $ 92 $ 60 $ 152 Other changes in fair value (65 ) (42 ) (107 ) 461 (364 ) 97 Fair value gains (losses), net $ 45 $ 3 $ 48 $ 553 $ (304 ) $ 249

Summary of Significant Accoun48

Summary of Significant Accounting Policies Related Parties (Details) - USD ($)	Sep. 30, 2015	Dec. 31, 2015	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Jun. 30, 2015	Dec. 31, 2014
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
Payments of cash dividends on senior preferred stock to Treasury	$ 4,400,000,000				$ 8,075,000,000	$ 16,594,000,000
Net worth	$ 4,003,000,000		$ 4,003,000,000		4,003,000,000		$ 6,200,000,000	$ 3,720,000,000
Income Taxes Paid					470,000,000	2,475,000,000
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees			413,000,000	$ 351,000,000	1,192,000,000	1,008,000,000
Other expense			$ 204,000,000	72,000,000	$ 412,000,000	479,000,000
Basis points of each dollar of unpaid principal balance	420.00%		420.00%		420.00%
Scenario, Forecast [Member]
Related Parties [Line Items]
Expected undeclared dividends payable on senior preferred stock for the next quarter		$ 2,200,000,000
US Treasury [Member]
Related Parties [Line Items]
Aggregate funding received from US Treasury pursuant to the senior preferred stock purchase agreement	$ 116,100,000,000		$ 116,100,000,000		$ 116,100,000,000
Initial aggregate liquidation preference of senior preferred stock held by US Treasury	1,000,000,000		1,000,000,000		1,000,000,000
Aggregate liquidation preference of senior preferred stock	117,100,000,000		117,100,000,000		117,100,000,000
Total available funding from US Treasury pursuant to the senior preferred stock agreement	117,600,000,000		117,600,000,000		117,600,000,000
Capital Reserve Amount, current year, Senior Preferred Stock Purchase Agreement, Amendment	1,800,000,000		1,800,000,000		1,800,000,000		$ 1,800,000,000
Capital Reserve Amount, prior year, Senior Preferred Stock Purchase Agreement, Amendment								2,400,000,000
Annual Reduction of Capital Reserve Amount from 2013 to 2018, Senior Preferred Stock Purchase Agreement, Amendment	$ 600,000,000		$ 600,000,000		$ 600,000,000
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			$ 18,000,000	18,000,000	$ 50,000,000	55,000,000
Income Taxes Paid			$ 100,000,000		470,000,000	2,500,000,000
Proceeds from Income Tax Refunds					$ 277,000,000
Percentage of initial principal loss US Treasury will bear for Temporary Credit and Liquidity Facilities and New Issue Bond Programs	35.00%		35.00%		35.00%
Loss of principal or interest under Treasury's Temporary Credit and Liquidity Facility and New Issue Bond Programs	$ 0		$ 0		$ 0
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees			413,000,000	351,000,000	1,192,000,000	1,008,000,000
US Treasury [Member] | Affordable Housing Allocation [Member]
Related Parties [Line Items]
Other expense			56,000,000		168,000,000
US Treasury [Member] | Single-family [Member]
Related Parties [Line Items]
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees			413,000,000	351,000,000	1,192,000,000	1,008,000,000
Recognized TCCA fees that had not been remitted to Treasury as of period end	413,000,000		413,000,000		413,000,000
US Treasury [Member] | Temporary Credit and Liquidity Facilities Program [Member]
Related Parties [Line Items]
Principal and interest outstanding	0		0		0			390,000,000
US Treasury [Member] | New Issue Bond Program [Member]
Related Parties [Line Items]
Principal and interest outstanding	3,900,000,000		3,900,000,000		3,900,000,000			4,200,000,000
Freddie Mac [Member] | Freddie Mac [Member]
Related Parties [Line Items]
Fair value of mortgage-related securities	$ 6,100,000,000		6,100,000,000		6,100,000,000			$ 6,900,000,000
Interest income recognized			55,000,000	68,000,000	174,000,000	219,000,000
Federal Housing Finance Agency [Member]
Related Parties [Line Items]
FHFA assessment fees			28,000,000	26,000,000	84,000,000	80,000,000
Common Securitization Solutions [Member]
Related Parties [Line Items]
Payments to Acquire Equity Method Investments			$ 17,000,000	$ 0	$ 47,000,000	$ 0

Summary of Significant Accoun49

Summary of Significant Accounting Policies Regulatory Capital (Details) - USD ($) $ in Billions	Sep. 30, 2015	Dec. 31, 2014
Accounting Policies [Abstract]
Deficit Of Core Capital Over Statutory Minimum Capital Requirement	$ 140.6	$ 142.2

Summary of Significant Accoun50

Summary of Significant Accounting Policies Use of Estimates (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014	Jan. 01, 2015
Change in Accounting Estimate [Line Items]
Minimum days past due of single family nonaccrual loans	60 days	60 days
Change in Accounting Method Accounted for as Change in Estimate [Member]
Change in Accounting Estimate [Line Items]
Advisory Bulletin impact for HFI loans			$ 1,800
Advisory Bulletin impact for preforeclosure property taxes and insurance receivable			$ 724

Summary of Significant Accoun51

Summary of Significant Accounting Policies Fee and Other Income (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Gain Contingencies [Line Items]
Fee and other income	$ 259,000,000	$ 826,000,000	$ 1,123,000,000	$ 5,564,000,000
Private Label Securities Settlements [Member]
Gain Contingencies [Line Items]
Fee and other income	$ 0	$ 538,000,000	$ 0	$ 4,800,000,000

Summary of Significant Accoun52

Summary of Significant Accounting Policies Employee Retirement Benefits (Details) - Pension Plan [Member] - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Settlement of defined pension benefit obligation, cash contribution	$ 102
Actuarial losses of defined pension benefit plan recorded in Administrative expenses	$ 305	$ 305

Consolidations and Transfers 53

Consolidations and Transfers of Financial Assets Unconsolidated VIEs (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Assets and liabilities recorded in our condensed consolidated balance sheets related to mortgage-backed trusts: [Abstract]
Trading, at fair value	$ 38,009	$ 31,504
Available-for-sale, at fair value	22,007	30,654
Other assets	18,674	19,992
Other liabilities	(10,400)	(12,019)
Unconsolidated VIEs [Member] | Mortgage-Backed Trusts [Member]
Assets and liabilities recorded in our condensed consolidated balance sheets related to mortgage-backed trusts: [Abstract]
Trading, at fair value	10,910	11,863
Available-for-sale, at fair value	20,190	27,819
Other assets	102	111
Other liabilities	(755)	(1,440)
Net carrying amount	30,447	38,353
Maximum exposure to loss	36,637	45,311
Total unconsolidated assets	252,211	253,554
Unconsolidated VIEs [Member] | Limited Partnership Investments [Member]
Assets and liabilities recorded in our condensed consolidated balance sheets related to mortgage-backed trusts: [Abstract]
Total unconsolidated assets	4,900	5,800
Fannie Mae Securities [Member]
Assets and liabilities recorded in our condensed consolidated balance sheets related to mortgage-backed trusts: [Abstract]
Trading, at fair value	4,977	4,790
Available-for-sale, at fair value	3,931	5,043
Non-Fannie Mae Securities [Member]
Assets and liabilities recorded in our condensed consolidated balance sheets related to mortgage-backed trusts: [Abstract]
Trading, at fair value	5,933	7,073
Available-for-sale, at fair value	$ 16,259	$ 22,776

Consolidations and Transfers 54

Consolidations and Transfers of Financial Assets WAC, WALA, WAM (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Transfers of Financial Assets [Line Items]
Unpaid principal balance portfolio securitizations	$ 55,400	$ 44,200	$ 166,300	$ 113,100
Unconsolidated VIEs [Member]
Transfers of Financial Assets [Line Items]
Principal and interest received on retained interests	273	$ 386	919	$ 1,100
Unconsolidated VIEs [Member] | Single Class MBS, REMIC & Megas [Member]
Transfers of Financial Assets [Line Items]
Unpaid principal balance of retained interests	5,400		5,400		$ 6,300
Fair value of retained interests	$ 6,700		$ 6,700		$ 7,600

Consolidations and Transfers 55

Consolidations and Transfers of Financial Assets Managed Loans (Details) - USD ($) $ in Billions	Sep. 30, 2015	Dec. 31, 2014
Consolidations and Transfers of Financial Assets [Abstract]
Securitized loans in unconsolidated portfolio securitization trusts, unpaid principal balance	$ 1.6	$ 1.8

Mortgage Loans Loans in Mortgag

Mortgage Loans Loans in Mortgage Portfolio (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2013
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	$ 3,012,689,000,000		$ 3,012,689,000,000		$ 3,019,300,000,000
Cost basis and fair value adjustments, net	36,902,000,000		36,902,000,000		35,735,000,000
Allowance for loan losses for loans held for investment	(29,135,000,000)	$ (36,931,000,000)	(29,135,000,000)	$ (36,931,000,000)	(35,541,000,000)	$ (31,150,000,000)	$ (39,067,000,000)	$ (43,846,000,000)
Total mortgage loans	3,020,456,000,000		3,020,456,000,000		$ 3,019,494,000,000
Carrying value of loans redesignated from HFI to HFS	1,300,000,000	0	5,900,000,000	2,200,000,000
Financing Receivable, Reclassification to Held-for-investment		240,000,000		241,000,000
Sale of loans, unpaid principal balance	1,900,000,000	0	$ 2,500,000,000	1,900,000,000
Minimum days past due of single family nonaccrual loans			60 days		60 days
Single-family [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	2,815,884,000,000		$ 2,815,884,000,000		$ 2,832,000,000,000
Recorded investment of single-family mortgage loans referred to foreclosure	27,600,000,000		27,600,000,000
Multifamily [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	196,805,000,000		196,805,000,000		187,300,000,000
Fannie Mae [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	257,768,000,000		257,768,000,000		285,371,000,000
Cost basis and fair value adjustments, net	(12,789,000,000)		(12,789,000,000)		(12,705,000,000)
Allowance for loan losses for loans held for investment	(27,655,000,000)	(34,562,000,000)	(27,655,000,000)	(34,562,000,000)	(33,117,000,000)	(29,724,000,000)	(36,643,000,000)	(40,521,000,000)
Total mortgage loans	217,324,000,000		217,324,000,000		239,549,000,000
Fannie Mae [Member] | Single-family [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	242,496,000,000		242,496,000,000		262,116,000,000
Fannie Mae [Member] | Multifamily [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	15,272,000,000		15,272,000,000		23,255,000,000
Consolidated Trusts [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	2,754,921,000,000		2,754,921,000,000		2,733,929,000,000
Cost basis and fair value adjustments, net	49,691,000,000		49,691,000,000		48,440,000,000
Allowance for loan losses for loans held for investment	(1,480,000,000)	$ (2,369,000,000)	(1,480,000,000)	$ (2,369,000,000)	(2,424,000,000)	$ (1,426,000,000)	$ (2,424,000,000)	$ (3,325,000,000)
Total mortgage loans	2,803,132,000,000		2,803,132,000,000		2,779,945,000,000
Consolidated Trusts [Member] | Single-family [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	2,573,388,000,000		2,573,388,000,000		2,569,884,000,000
Consolidated Trusts [Member] | Multifamily [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	$ 181,533,000,000		$ 181,533,000,000		$ 164,045,000,000

Mortgage Loans Aging (Details)

Mortgage Loans Aging (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	$ 35,356	$ 34,867
60 - 89 days delinquent	9,571	10,352
Seriously delinquent	38,654	54,008
Total delinquent	83,581	99,227
Current	2,955,659	2,948,567
Total recorded investment in loans	3,039,240	3,047,794
Recorded investment in loans 90 days or more delinquent and accruing interest	358	374
Recorded investment in nonaccrual loans	48,399	64,645
Single-family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	35,319	34,807
60 - 89 days delinquent	9,571	10,352
Seriously delinquent	38,566	53,919
Total delinquent	83,456	99,078
Current	2,757,085	2,759,483
Total recorded investment in loans	2,840,541	2,858,561
Recorded investment in loans 90 days or more delinquent and accruing interest	358	374
Recorded investment in nonaccrual loans	$ 47,720	$ 63,822
Single-family [Member] | Minimum [Member]
Table Footnote [Abstract]
Serious delinquency, days past due	90 days	90 days
Single-family [Member] | Primary [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	$ 29,574	$ 29,130
60 - 89 days delinquent	7,766	8,396
Seriously delinquent	28,417	38,248
Total delinquent	65,757	75,774
Current	2,594,488	2,580,446
Total recorded investment in loans	2,660,245	2,656,220
Recorded investment in loans 90 days or more delinquent and accruing interest	49	55
Recorded investment in nonaccrual loans	36,108	46,556
Single-family [Member] | Government [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	57	63
60 - 89 days delinquent	25	26
Seriously delinquent	295	305
Total delinquent	377	394
Current	41,342	44,927
Total recorded investment in loans	41,719	45,321
Recorded investment in loans 90 days or more delinquent and accruing interest	295	305
Recorded investment in nonaccrual loans	0	0
Single-family [Member] | Alt-A
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	4,126	4,094
60 - 89 days delinquent	1,291	1,414
Seriously delinquent	7,407	11,603
Total delinquent	12,824	17,111
Current	87,525	95,650
Total recorded investment in loans	100,349	112,761
Recorded investment in loans 90 days or more delinquent and accruing interest	7	8
Recorded investment in nonaccrual loans	8,690	13,007
Single-family [Member] | Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	1,562	1,520
60 - 89 days delinquent	489	516
Seriously delinquent	2,447	3,763
Total delinquent	4,498	5,799
Current	33,730	38,460
Total recorded investment in loans	38,228	44,259
Recorded investment in loans 90 days or more delinquent and accruing interest	7	6
Recorded investment in nonaccrual loans	2,922	4,259
Multifamily [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	37	60
Seriously delinquent	88	89
Total delinquent	125	149
Current	198,574	189,084
Total recorded investment in loans	198,699	189,233
Recorded investment in loans 90 days or more delinquent and accruing interest	0	0
Recorded investment in nonaccrual loans	$ 679	$ 823
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

Mortgage Loans Credit Quality I

Mortgage Loans Credit Quality Indicators - SF (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	$ 3,039,240	$ 3,047,794
Single-family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	2,840,541	2,858,561
Single-family [Member] | Primary [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	2,660,245	2,656,220
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	2,248,367	2,156,165
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	240,860	261,709
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	108,540	140,778
Single-family [Member] | Primary [Member] | Estimated mark-to-market loan-to-value ratio greater than 100% and less than or equal to 110% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	28,684	43,014
Single-family [Member] | Primary [Member] | Estimated mark-to-market loan-to-value ratio greater than 110% and less than or equal to 120% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	15,115	23,439
Single-family [Member] | Primary [Member] | Estimated mark-to-market loan-to-value ratio greater than 120% and less than or equal to 125% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	4,706	7,529
Single-family [Member] | Primary [Member] | Estimated mark-to-market loan-to-value ratio greater than 125% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	13,973	23,586
Single-family [Member] | Alt-A
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	100,349	112,761
Single-family [Member] | Alt-A | 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	61,367	60,851
Single-family [Member] | Alt-A | 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	13,188	15,151
Single-family [Member] | Alt-A | 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	9,758	12,490
Single-family [Member] | Alt-A | Estimated mark-to-market loan-to-value ratio greater than 100% and less than or equal to 110% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	6,528	8,998
Single-family [Member] | Alt-A | Estimated mark-to-market loan-to-value ratio greater than 110% and less than or equal to 120% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	4,018	6,033
Single-family [Member] | Alt-A | Estimated mark-to-market loan-to-value ratio greater than 120% and less than or equal to 125% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	1,295	2,114
Single-family [Member] | Alt-A | Estimated mark-to-market loan-to-value ratio greater than 125% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	4,195	7,124
Single-family [Member] | Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	38,228	44,259
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	22,263	22,558
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	5,197	6,046
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	4,020	5,236
Single-family [Member] | Other [Member] | Estimated mark-to-market loan-to-value ratio greater than 100% and less than or equal to 110% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	2,787	3,900
Single-family [Member] | Other [Member] | Estimated mark-to-market loan-to-value ratio greater than 110% and less than or equal to 120% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	1,699	2,615
Single-family [Member] | Other [Member] | Estimated mark-to-market loan-to-value ratio greater than 120% and less than or equal to 125% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	552	904
Single-family [Member] | Other [Member] | Estimated mark-to-market loan-to-value ratio greater than 125% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	1,710	3,000
Single-family [Member] | Government [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	$ 41,719	$ 45,321

Mortgage Loans Credit Quality59

Mortgage Loans Credit Quality Indicators - MF (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	$ 3,039,240	$ 3,047,794
Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	198,699	189,233
Multifamily [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	192,767	182,079
Multifamily [Member] | Special mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	2,725	3,070
Multifamily [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	3,203	3,842
Multifamily [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	$ 4	$ 242

Mortgage Loans Individually Imp

Mortgage Loans Individually Impaired Loans (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	$ 165,417	$ 177,630
Individually impaired loans with related allowance recorded: total recorded investment	155,818	168,510
Related allowance for loan losses	26,517	31,375
Individually impaired loans with no related allowance recorded: unpaid principal balance	22,945	22,563
Individually impaired loans with no related allowance recorded: total recorded investment	20,820	19,676
Total individually impaired loans: unpaid principal balance	188,362	200,193
Total individually impaired loans: total recorded investment	176,638	188,186
Interest Receivable [Member]
Financing Receivable, Impaired [Line Items]
Related allowance for loan losses		501
Single-family [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	164,629	176,400
Individually impaired loans with related allowance recorded: total recorded investment	155,025	167,269
Related allowance for loan losses	26,404	31,200
Individually impaired loans with no related allowance recorded: unpaid principal balance	22,581	21,998
Individually impaired loans with no related allowance recorded: total recorded investment	20,454	19,108
Single-family [Member] | Interest Receivable [Member]
Financing Receivable, Impaired [Line Items]
Related allowance for loan losses		495
Single-family [Member] | Primary [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	118,495	125,960
Individually impaired loans with related allowance recorded: total recorded investment	112,430	120,221
Related allowance for loan losses	17,374	20,327
Individually impaired loans with no related allowance recorded: unpaid principal balance	16,930	16,704
Individually impaired loans with no related allowance recorded: total recorded investment	15,600	14,876
Single-family [Member] | Primary [Member] | Interest Receivable [Member]
Financing Receivable, Impaired [Line Items]
Related allowance for loan losses		309
Single-family [Member] | Government [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	324	281
Individually impaired loans with related allowance recorded: total recorded investment	329	285
Related allowance for loan losses	62	46
Individually impaired loans with no related allowance recorded: unpaid principal balance	60	61
Individually impaired loans with no related allowance recorded: total recorded investment	56	57
Single-family [Member] | Government [Member] | Interest Receivable [Member]
Financing Receivable, Impaired [Line Items]
Related allowance for loan losses		12
Single-family [Member] | Alt-A
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	32,593	35,492
Individually impaired loans with related allowance recorded: total recorded investment	29,777	32,816
Related allowance for loan losses	6,454	7,778
Individually impaired loans with no related allowance recorded: unpaid principal balance	4,235	3,993
Individually impaired loans with no related allowance recorded: total recorded investment	3,580	3,119
Single-family [Member] | Alt-A | Interest Receivable [Member]
Financing Receivable, Impaired [Line Items]
Related allowance for loan losses		136
Single-family [Member] | Other [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	13,217	14,667
Individually impaired loans with related allowance recorded: total recorded investment	12,489	13,947
Related allowance for loan losses	2,514	3,049
Individually impaired loans with no related allowance recorded: unpaid principal balance	1,356	1,240
Individually impaired loans with no related allowance recorded: total recorded investment	1,218	1,056
Single-family [Member] | Other [Member] | Interest Receivable [Member]
Financing Receivable, Impaired [Line Items]
Related allowance for loan losses		38
Multifamily [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	788	1,230
Individually impaired loans with related allowance recorded: total recorded investment	793	1,241
Related allowance for loan losses	113	175
Individually impaired loans with no related allowance recorded: unpaid principal balance	364	565
Individually impaired loans with no related allowance recorded: total recorded investment	$ 366	568
Multifamily [Member] | Interest Receivable [Member]
Financing Receivable, Impaired [Line Items]
Related allowance for loan losses		$ 6

Mortgage Loans Individually I61

Mortgage Loans Individually Impaired Loans - 2 (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	$ 157,504	$ 170,875	$ 160,895	$ 173,083
Individually impaired loans with no related allowance recorded: average recorded investment	20,999	19,964	21,492	18,914
Individually impaired loans with related allowance recorded: total interest income recognized	1,469	1,465	4,232	4,446
Individually impaired loans with no related allowance recorded: total interest income recognized	370	312	1,004	853
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	91	143	304	474
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	17	73	86	199
Individually impaired loans: average recorded investment	178,503	190,839	182,387	191,997
Individually impaired loans: total interest income recognized	1,839	1,777	5,236	5,299
Individually impaired loans: interest income recognized on a cash basis	108	216	390	673
Table Footnote [Abstract]
Individually impaired loans: total interest income recognized	1,839	1,777	5,236	5,299
Single-family [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans: total interest income recognized	1,800	1,800
Table Footnote [Abstract]
Individually impaired loans: total interest income recognized	1,800	1,800
Individually impaired loans: contractual interest income	1,500	1,400
Single-family [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	156,626	169,335	159,842	171,270
Individually impaired loans with no related allowance recorded: average recorded investment	20,613	18,392	21,029	17,216
Individually impaired loans with related allowance recorded: total interest income recognized	1,460	1,448	4,217	4,383
Individually impaired loans with no related allowance recorded: total interest income recognized	365	294	996	795
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	91	143	304	474
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	17	73	86	199
Individually impaired loans: total interest income recognized			5,200	5,200
Table Footnote [Abstract]
Troubled debt restructuring recorded investment	174,600		174,600		$ 185,200
Individually impaired loans: total interest income recognized			5,200	5,200
Individually impaired loans: contractual interest income			4,300	4,300
Individually impaired loans: effective yield adjustments	327	297	907	857
Single-family [Member] | Primary [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	113,634	121,246	115,762	122,443
Individually impaired loans with no related allowance recorded: average recorded investment	15,627	14,442	15,967	13,514
Individually impaired loans with related allowance recorded: total interest income recognized	1,090	1,077	3,152	3,264
Individually impaired loans with no related allowance recorded: total interest income recognized	279	226	779	616
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	71	111	248	372
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	16	56	76	157
Single-family [Member] | Government [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	299	285	290	266
Individually impaired loans with no related allowance recorded: average recorded investment	53	55	55	70
Individually impaired loans with related allowance recorded: total interest income recognized	3	3	9	9
Individually impaired loans with no related allowance recorded: total interest income recognized	1	1	3	4
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: interest income recognized on a cash basis	0	0	0	0
Single-family [Member] | Alt-A
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	30,041	33,458	30,760	33,926
Individually impaired loans with no related allowance recorded: average recorded investment	3,674	2,887	3,720	2,687
Individually impaired loans with related allowance recorded: total interest income recognized	272	268	774	805
Individually impaired loans with no related allowance recorded: total interest income recognized	64	51	158	135
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	14	24	41	74
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	1	14	8	34
Single-family [Member] | Other [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	12,652	14,346	13,030	14,635
Individually impaired loans with no related allowance recorded: average recorded investment	1,259	1,008	1,287	945
Individually impaired loans with related allowance recorded: total interest income recognized	95	100	282	305
Individually impaired loans with no related allowance recorded: total interest income recognized	21	16	56	40
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	6	8	15	28
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	0	3	2	8
Multifamily [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	878	1,540	1,053	1,813
Individually impaired loans with no related allowance recorded: average recorded investment	386	1,572	463	1,698
Individually impaired loans with related allowance recorded: total interest income recognized	9	17	15	63
Individually impaired loans with no related allowance recorded: total interest income recognized	5	18	8	58
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: interest income recognized on a cash basis	0	$ 0	0	$ 0
Table Footnote [Abstract]
Troubled debt restructuring recorded investment	$ 490		$ 490		$ 716

Mortgage Loans TDR (Details)

Mortgage Loans TDR (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015USD ($)contracts	Sep. 30, 2014USD ($)contracts	Sep. 30, 2015USD ($)contracts	Sep. 30, 2014USD ($)contracts
Financing Receivable, Modifications [Line Items]
Average term extension of a single-family modified loan	159 months	162 months	161 months	161 months
Average interest rate reduction of a single-family modified loan	0.69%	0.89%	0.75%	1.04%
Number of loans troubled debt restructurings activity | contracts	17,112	27,028	63,063	90,950
Recorded investment troubled debt restructurings activity	$ 2,362	$ 4,756	$ 8,847	$ 14,241
Number of loans troubled debt restructurings subsequent default | contracts	8,258	10,647	23,907	31,240
Recorded investment troubled debt restructurings subsequent default	$ 1,254	$ 1,664	$ 3,611	$ 4,961
Single-family [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity | contracts	17,109	27,021	63,056	90,934
Recorded investment troubled debt restructurings activity	$ 2,352	$ 3,945	$ 8,831	$ 13,392
Number of loans troubled debt restructurings subsequent default | contracts	8,258	10,646	23,904	31,234
Recorded investment troubled debt restructurings subsequent default	$ 1,254	$ 1,659	$ 3,605	$ 4,939
Single-family [Member] | Primary [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity | contracts	14,926	23,057	54,284	76,831
Recorded investment troubled debt restructurings activity	$ 2,021	$ 3,270	$ 7,443	$ 10,944
Number of loans troubled debt restructurings subsequent default | contracts	6,847	8,798	19,726	25,586
Recorded investment troubled debt restructurings subsequent default	$ 1,003	$ 1,312	$ 2,870	$ 3,873
Single-family [Member] | Government [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity | contracts	54	91	192	264
Recorded investment troubled debt restructurings activity	$ 6	$ 12	$ 22	$ 33
Number of loans troubled debt restructurings subsequent default | contracts	31	38	88	74
Recorded investment troubled debt restructurings subsequent default	$ 3	$ 6	$ 12	$ 9
Single-family [Member] | Alt-A
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity | contracts	1,805	3,175	7,127	11,231
Recorded investment troubled debt restructurings activity	$ 268	$ 521	$ 1,101	$ 1,875
Number of loans troubled debt restructurings subsequent default | contracts	1,052	1,372	3,168	4,212
Recorded investment troubled debt restructurings subsequent default	$ 183	$ 241	$ 537	$ 753
Single-family [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity | contracts	324	698	1,453	2,608
Recorded investment troubled debt restructurings activity	$ 57	$ 142	$ 265	$ 540
Number of loans troubled debt restructurings subsequent default | contracts	328	438	922	1,362
Recorded investment troubled debt restructurings subsequent default	$ 65	$ 100	$ 186	$ 304
Multifamily [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity | contracts	3	7	7	16
Recorded investment troubled debt restructurings activity	$ 10	$ 811	$ 16	$ 849
Number of loans troubled debt restructurings subsequent default | contracts	0	1	3	6
Recorded investment troubled debt restructurings subsequent default	$ 0	$ 5	$ 6	$ 22

Allowance for Loan Losses Rollf

Allowance for Loan Losses Rollforward by Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Jan. 01, 2015
Allowance for Loan Losses [Roll Forward]
Beginning balance	$ 31,150	$ 39,067	$ 35,541	$ 43,846
Provision (benefit) for loan losses	(1,394)	(1,051)	(357)	(3,481)
Charge-offs	(777)	(1,561)	(8,213)	(5,071)
Recoveries	168	275	1,051	1,124
Transfers	0	0	0	0
Other	(12)	201	1,113	513
Ending balance	29,135	36,931	29,135	36,931
Nonaccrual Policy [Member]
Table Footnote [Abstract]
Allowance for accrued interest receivables, charge-offs					$ 1,100
Change in Accounting Method Accounted for as Change in Estimate [Member]
Table Footnote [Abstract]
Advisory Bulletin impact for HFI loans					1,800
Advisory Bulletin impact for preforeclosure property taxes and insurance receivable					$ 724
Fannie Mae [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	29,724	36,643	33,117	40,521
Provision (benefit) for loan losses	(1,732)	(1,439)	(290)	(3,629)
Charge-offs	(753)	(1,453)	(8,147)	(4,820)
Recoveries	165	271	1,036	902
Transfers	263	368	878	1,127
Other	(12)	172	1,061	461
Ending balance	27,655	34,562	27,655	34,562
Consolidated Trusts [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	1,426	2,424	2,424	3,325
Provision (benefit) for loan losses	338	388	(67)	148
Charge-offs	(24)	(108)	(66)	(251)
Recoveries	3	4	15	222
Transfers	(263)	(368)	(878)	(1,127)
Other	0	29	52	52
Ending balance	1,480	2,369	1,480	2,369
Single-family [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	30,876	38,643	35,177	43,307
Provision (benefit) for loan losses	(1,392)	(999)	(293)	(3,371)
Charge-offs	(770)	(1,547)	(8,172)	(4,998)
Recoveries	164	275	1,047	1,124
Transfers	0	0	0	0
Other	(13)	198	1,106	508
Ending balance	28,865	36,570	28,865	36,570
Single-family [Member] | Fannie Mae [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	29,624	36,400	32,956	40,202
Provision (benefit) for loan losses	(1,722)	(1,393)	(249)	(3,563)
Charge-offs	(748)	(1,439)	(8,108)	(4,747)
Recoveries	161	271	1,032	902
Transfers	262	366	877	1,123
Other	(13)	170	1,056	458
Ending balance	27,564	34,375	27,564	34,375
Single-family [Member] | Consolidated Trusts [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	1,252	2,243	2,221	3,105
Provision (benefit) for loan losses	330	394	(44)	192
Charge-offs	(22)	(108)	(64)	(251)
Recoveries	3	4	15	222
Transfers	(262)	(366)	(877)	(1,123)
Other	0	28	50	50
Ending balance	1,301	2,195	1,301	2,195
Multifamily [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	274	424	364	539
Provision (benefit) for loan losses	(2)	(52)	(64)	(110)
Charge-offs	(7)	(14)	(41)	(73)
Recoveries	4	0	4	0
Transfers	0	0	0	0
Other	1	3	7	5
Ending balance	270	361	270	361
Multifamily [Member] | Fannie Mae [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	100	243	161	319
Provision (benefit) for loan losses	(10)	(46)	(41)	(66)
Charge-offs	(5)	(14)	(39)	(73)
Recoveries	4	0	4	0
Transfers	1	2	1	4
Other	1	2	5	3
Ending balance	91	187	91	187
Multifamily [Member] | Consolidated Trusts [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	174	181	203	220
Provision (benefit) for loan losses	8	(6)	(23)	(44)
Charge-offs	(2)	0	(2)	0
Recoveries	0	0	0	0
Transfers	(1)	(2)	(1)	(4)
Other	0	1	2	2
Ending balance	$ 179	$ 174	$ 179	$ 174

Allowance for Loan Losses and T

Allowance for Loan Losses and Total Recorded Investment in HFI Loans (Details) - USD ($) $ in Millions	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	$ 26,517		$ 31,375
Allowance for loan losses for collectively reserved loans	2,618		4,166
Total allowance for loan losses	29,135	$ 31,150	35,541	$ 36,931	$ 39,067	$ 43,846
Recorded investment in individually impaired loans	176,638		188,186
Recorded investment in collectively reserved loans	2,862,602		2,859,608
Total recorded investment in loans	3,039,240		3,047,794
Single-family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	26,404		31,200
Allowance for loan losses for collectively reserved loans	2,461		3,977
Total allowance for loan losses	28,865	30,876	35,177	36,570	38,643	43,307
Recorded investment in individually impaired loans	175,479		186,377
Recorded investment in collectively reserved loans	2,665,062		2,672,184
Total recorded investment in loans	2,840,541		2,858,561
Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	113		175
Allowance for loan losses for collectively reserved loans	157		189
Total allowance for loan losses	270	$ 274	364	$ 361	$ 424	$ 539
Recorded investment in individually impaired loans	1,159		1,809
Recorded investment in collectively reserved loans	197,540		187,424
Total recorded investment in loans	$ 198,699		$ 189,233

Investments in Securities Tradi

Investments in Securities Trading 1 (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	$ 38,009	$ 31,504
Mortgage-related securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	11,048	12,038
Fannie Mae [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	5,097	4,940
Freddie Mac [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	1,474	1,369
Ginnie Mae [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	353	166
Alt-A private-label securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	451	920
Subprime private-label securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	696	1,307
CMBS [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	2,398	2,515
Mortgage revenue bonds [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	579	722
Other mortgage-related securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	0	99
U.S. Treasury securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	$ 26,961	$ 19,466

Investments in Securities Tra66

Investments in Securities Trading 2 (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]
Net trading gains	$ 13	$ 50	$ 69	$ 444
Net trading gains (losses) recognized in the period related to securities still held at period end	$ (15)	$ 56	$ (29)	$ 409

Investments in Securities Avail

Investments in Securities Available-for-sale Securities 1 (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]
Gross realized gains	$ 94	$ 96	$ 907	$ 495
Gross realized losses	9	4	66	5
Total proceeds	$ 1,556	$ 722	$ 6,764	$ 2,461

Investments in Securities Ava68

Investments in Securities Available-for-sale Securities 2 (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	$ 19,587	$ 27,413
Gross unrealized gains	2,471	3,448
Gross unrealized losses - OTTI	(24)	(55)
Gross unrealized losses - Other	(27)	(152)
Total Available-for-Sale, at Fair Value	22,007	30,654
Fannie Mae [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	4,026	5,330
Gross unrealized gains	275	328
Gross unrealized losses - OTTI	0	0
Gross unrealized losses - Other	(19)	(19)
Total Available-for-Sale, at Fair Value	4,282	5,639
Freddie Mac [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	4,252	5,100
Gross unrealized gains	347	428
Gross unrealized losses - OTTI	0	0
Gross unrealized losses - Other	0	0
Total Available-for-Sale, at Fair Value	4,599	5,528
Ginnie Mae [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	361	416
Gross unrealized gains	52	60
Gross unrealized losses - OTTI	0	0
Gross unrealized losses - Other	0	0
Total Available-for-Sale, at Fair Value	413	476
Alt-A private-label securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	2,626	4,638
Gross unrealized gains	727	1,055
Gross unrealized losses - OTTI	(4)	(15)
Gross unrealized losses - Other	0	0
Total Available-for-Sale, at Fair Value	3,349	5,678
Subprime private-label securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	2,817	4,103
Gross unrealized gains	865	1,161
Gross unrealized losses - OTTI	0	(9)
Gross unrealized losses - Other	(5)	(15)
Total Available-for-Sale, at Fair Value	3,677	5,240
CMBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	1,273	1,341
Gross unrealized gains	36	56
Gross unrealized losses - OTTI	0	0
Gross unrealized losses - Other	0	0
Total Available-for-Sale, at Fair Value	1,309	1,397
Mortgage revenue bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	2,824	3,859
Gross unrealized gains	129	177
Gross unrealized losses - OTTI	(17)	(8)
Gross unrealized losses - Other	(3)	(5)
Total Available-for-Sale, at Fair Value	2,933	4,023
Other mortgage-related securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	1,408	2,626
Gross unrealized gains	40	183
Gross unrealized losses - OTTI	(3)	(23)
Gross unrealized losses - Other	0	(113)
Total Available-for-Sale, at Fair Value	$ 1,445	$ 2,673

Investments in Securities Ava69

Investments in Securities Available-for-sale Securities 3 (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Consecutive Months, Gross Unrealized Losses	$ (23)	$ (4)
Less than 12 Consecutive Months, Fair Value	1,125	339
12 Consecutive Months or Longer, Gross Unrealized Losses	(28)	(203)
12 Consecutive Months or Longer, Fair Value	655	2,375
Fannie Mae [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Consecutive Months, Gross Unrealized Losses	(3)	0
Less than 12 Consecutive Months, Fair Value	116	113
12 Consecutive Months or Longer, Gross Unrealized Losses	(16)	(19)
12 Consecutive Months or Longer, Fair Value	511	627
Alt-A private-label securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Consecutive Months, Gross Unrealized Losses	(1)	(2)
Less than 12 Consecutive Months, Fair Value	132	171
12 Consecutive Months or Longer, Gross Unrealized Losses	(3)	(13)
12 Consecutive Months or Longer, Fair Value	28	112
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	38	0
12 Consecutive Months or Longer, Gross Unrealized Losses	(5)	(24)
12 Consecutive Months or Longer, Fair Value	96	460
Mortgage revenue bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Consecutive Months, Gross Unrealized Losses	(16)	(2)
Less than 12 Consecutive Months, Fair Value	584	47
12 Consecutive Months or Longer, Gross Unrealized Losses	(4)	(11)
12 Consecutive Months or Longer, Fair Value	20	155
Other mortgage-related securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Consecutive Months, Gross Unrealized Losses	(3)	0
Less than 12 Consecutive Months, Fair Value	255	8
12 Consecutive Months or Longer, Gross Unrealized Losses	0	(136)
12 Consecutive Months or Longer, Fair Value	$ 0	$ 1,021

Investments in Securities Other

Investments in Securities Other-than-temporary Impairments 1 (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]
OTTI recognized in Investment gains, net	$ 5	$ 6	$ 187	$ 80
Subprime private-label securities [Member]
UPB and Modeled Attributes [Line Items]
Total unpaid principal balance	$ 4,917		$ 4,917
Weighted average collateral default	42.40%		42.40%
Weighted average collateral severities	60.00%		60.00%
Weighted average voluntary prepayment rates	2.70%		2.70%
Average credit enhancement	17.40%		17.40%
Alt-A Option ARM [Member]
UPB and Modeled Attributes [Line Items]
Total unpaid principal balance	$ 494		$ 494
Weighted average collateral default	29.40%		29.40%
Weighted average collateral severities	38.50%		38.50%
Weighted average voluntary prepayment rates	7.40%		7.40%
Average credit enhancement	3.60%		3.60%
Alt-A Fixed Rate [Member]
UPB and Modeled Attributes [Line Items]
Total unpaid principal balance	$ 1,205		$ 1,205
Weighted average collateral default	11.90%		11.90%
Weighted average collateral severities	46.90%		46.90%
Weighted average voluntary prepayment rates	12.20%		12.20%
Average credit enhancement	5.60%		5.60%
Alt-A Variable Rate [Member]
UPB and Modeled Attributes [Line Items]
Total unpaid principal balance	$ 838		$ 838
Weighted average collateral default	21.40%		21.40%
Weighted average collateral severities	37.90%		37.90%
Weighted average voluntary prepayment rates	8.40%		8.40%
Average credit enhancement	8.60%		8.60%
Alt-A Hybrid Rate [Member]
UPB and Modeled Attributes [Line Items]
Total unpaid principal balance	$ 1,237		$ 1,237
Weighted average collateral default	10.00%		10.00%
Weighted average collateral severities	34.20%		34.20%
Weighted average voluntary prepayment rates	12.00%		12.00%
Average credit enhancement	4.40%		4.40%

Investments in Securities Oth71

Investments in Securities Other-than-temporary Impairments 2 (Details) - Available-for-sale securities [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance, beginning of period	$ 2,557	$ 5,871	$ 5,260	$ 7,904
Additions for the credit component on debt securities for which OTTI was not previously recognized	0	0	0	1
Additions for the credit component on debt securities for which OTTI was previously recognized	1	3	5	50
Reductions for securities no longer in portfolio at period end	(2)	(355)	(1,167)	(792)
Reductions for securities which we intend to sell or it is more likely than not that we will be required to sell before recovery of amortized cost basis	0	0	(1,439)	(1,453)
Reductions for amortization resulting from changes in cash flows expected to be collected over the remaining life of the securities	(43)	(73)	(146)	(264)
Balance, end of period	$ 2,513	$ 5,446	$ 2,513	$ 5,446

Investments in Securities Matur

Investments in Securities Maturity Information (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total Amortized Cost	$ 19,587	$ 27,413
Total Available-for-Sale, at Fair Value	22,007	30,654
One Year or Less, Amortized Cost	183
One Year or Less, Fair Value	185
After One Year through Five Years, Amortized Cost	1,554
After One Year through Five Years, Fair Value	1,605
After Five Years through Ten Years, Amortized Cost	804
After Five Years through Ten Years, Fair Value	859
After Ten Years, Amortized Cost	17,046
After Ten Years, Fair Value	19,358
Fannie Mae [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total Amortized Cost	4,026	5,330
Total Available-for-Sale, at Fair Value	4,282	5,639
One Year or Less, Amortized Cost	0
One Year or Less, Fair Value	0
After One Year through Five Years, Amortized Cost	189
After One Year through Five Years, Fair Value	194
After Five Years through Ten Years, Amortized Cost	165
After Five Years through Ten Years, Fair Value	178
After Ten Years, Amortized Cost	3,672
After Ten Years, Fair Value	3,910
Freddie Mac [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total Amortized Cost	4,252	5,100
Total Available-for-Sale, at Fair Value	4,599	5,528
One Year or Less, Amortized Cost	1
One Year or Less, Fair Value	1
After One Year through Five Years, Amortized Cost	221
After One Year through Five Years, Fair Value	231
After Five Years through Ten Years, Amortized Cost	332
After Five Years through Ten Years, Fair Value	363
After Ten Years, Amortized Cost	3,698
After Ten Years, Fair Value	4,004
Ginnie Mae [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total Amortized Cost	361	416
Total Available-for-Sale, at Fair Value	413	476
One Year or Less, Amortized Cost	0
One Year or Less, Fair Value	0
After One Year through Five Years, Amortized Cost	1
After One Year through Five Years, Fair Value	1
After Five Years through Ten Years, Amortized Cost	57
After Five Years through Ten Years, Fair Value	64
After Ten Years, Amortized Cost	303
After Ten Years, Fair Value	348
Alt-A private-label securities [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total Amortized Cost	2,626	4,638
Total Available-for-Sale, at Fair Value	3,349	5,678
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	2,626
After Ten Years, Fair Value	3,349
Subprime private-label securities [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total Amortized Cost	2,817	4,103
Total Available-for-Sale, at Fair Value	3,677	5,240
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	2,817
After Ten Years, Fair Value	3,677
CMBS [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total Amortized Cost	1,273	1,341
Total Available-for-Sale, at Fair Value	1,309	1,397
One Year or Less, Amortized Cost	171
One Year or Less, Fair Value	173
After One Year through Five Years, Amortized Cost	1,037
After One Year through Five Years, Fair Value	1,071
After Five Years through Ten Years, Amortized Cost	0
After Five Years through Ten Years, Fair Value	0
After Ten Years, Amortized Cost	65
After Ten Years, Fair Value	65
Mortgage revenue bonds [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total Amortized Cost	2,824	3,859
Total Available-for-Sale, at Fair Value	2,933	4,023
One Year or Less, Amortized Cost	11
One Year or Less, Fair Value	11
After One Year through Five Years, Amortized Cost	106
After One Year through Five Years, Fair Value	108
After Five Years through Ten Years, Amortized Cost	219
After Five Years through Ten Years, Fair Value	221
After Ten Years, Amortized Cost	2,488
After Ten Years, Fair Value	2,593
Other mortgage-related securities [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total Amortized Cost	1,408	2,626
Total Available-for-Sale, at Fair Value	1,445	$ 2,673
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	31
After Five Years through Ten Years, Fair Value	33
After Ten Years, Amortized Cost	1,377
After Ten Years, Fair Value	$ 1,412

Financial Guarantees and Maximu

Financial Guarantees and Maximum Recovery (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Financial Guarantees and Maximum Recovery [Line Items]
Maximum Exposure	$ 32,339	$ 35,965
Guaranty Obligation	338	382
Maximum Recovery	12,048	14,222
Fair Value of guaranty obligations in Investments in Securities	729	797
Unconsolidated VIEs [Member] | Unconsolidated Fannie Mae MBS [Member]
Financial Guarantees and Maximum Recovery [Line Items]
Maximum Exposure	15,556	17,184
Guaranty Obligation	198	214
Maximum Recovery	9,077	9,775
Unconsolidated VIEs [Member] | Other guaranty arrangements [Member]
Financial Guarantees and Maximum Recovery [Line Items]
Maximum Exposure	16,783	18,781
Guaranty Obligation	140	168
Maximum Recovery	$ 2,971	$ 4,447
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	37 years

Acquired Property Net (Details)

Acquired Property Net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Acquired Property [Roll Forward]
Beginning balance - Acquired property	$ 9,199	$ 12,296	$ 11,442	$ 12,307
Additions - Acquired property	2,236	3,240	7,602	10,437
Disposals - Acquired property	(3,125)	(3,412)	(10,734)	(10,620)
Ending balance - Acquired property	8,310	12,124	8,310	12,124
Real Estate Owned Valuation Allowance [Roll Forward]
Beginning balance - Valuation allowance	(693)	(736)	(824)	(686)
Decrease (increase) in Valuation allowance	74	(49)	205	(99)
Ending balance - Valuation allowance	(619)	(785)	(619)	(785)
Ending balance - Acquired property, net	$ 7,691	$ 11,339	$ 7,691	$ 11,339	$ 10,618

Short-Term Borrowings and Lon75

Short-Term Borrowings and Long-Term Debt Short-Term Debt (Details) - USD ($)	Sep. 30, 2015	Dec. 31, 2014
Short-Term Borrowings [Line Items]
Federal funds purchased and securities sold under agreements to repurchase, outstanding	$ 118,000,000	$ 50,000,000
Federal funds purchased and securities sold under agreements to repurchase, weighted-average interest rate	0.00%	0.00%
Short-term debt, outstanding	$ 96,818,000,000	$ 106,572,000,000
Short-term debt, weighted-average interest rate	0.20%	0.11%
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	$ 95,427,000,000	$ 105,012,000,000
Short-term debt, weighted-average interest rate	0.21%	0.11%
Consolidated Trusts [Member]
Short-Term Borrowings [Line Items]
Short-term debt, outstanding	$ 1,391,000,000	$ 1,560,000,000
Short-term debt, weighted-average interest rate	0.15%	0.09%

Short-Term Borrowings and Lon76

Short-Term Borrowings and Long-Term Debt Long-Term Debt (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 3,109,427	$ 3,115,583
Long-term debt, weighted-average interest rate	2.85%	2.93%
Fannie Mae [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 322,031	$ 355,431
Long-term debt, weighted-average interest rate	2.39%	2.24%
Unamortized discounts and premiums, other cost basis adjustments and fair value adjustments	$ 3,400	$ 4,100
Fannie Mae [Member] | Senior Fixed [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 288,599	$ 320,507
Long-term debt, weighted-average interest rate	2.39%	2.29%
Fannie Mae [Member] | Senior fixed benchmark notes and bonds [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 159,550	$ 173,010
Long-term debt, weighted-average interest rate	2.51%	2.41%
Fannie Mae [Member] | Senior fixed medium-term notes [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 100,682	$ 114,556
Long-term debt, weighted-average interest rate	1.49%	1.42%
Fannie Mae [Member] | Senior fixed foreign exchange bonds [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 570	$ 619
Long-term debt, weighted-average interest rate	5.39%	5.44%
Fannie Mae [Member] | Senior fixed other debt [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 27,797	$ 32,322
Long-term debt, weighted-average interest rate	4.83%	4.63%
Fannie Mae [Member] | Senior Floating [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 29,140	$ 30,873
Long-term debt, weighted-average interest rate	1.36%	0.81%
Fannie Mae [Member] | Senior floating medium-term notes [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 19,164	$ 24,469
Long-term debt, weighted-average interest rate	0.22%	0.15%
Fannie Mae [Member] | Senior floating Connecticut Avenue Security [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 9,607	$ 6,041
Long-term debt, weighted-average interest rate	3.39%	2.97%
Fannie Mae [Member] | Senior floating other debt [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 369	$ 363
Long-term debt, weighted-average interest rate	8.25%	8.71%
Fannie Mae [Member] | Subordinated debentures [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 4,129	$ 3,849
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	$ 163	$ 202
Long-term debt, weighted-average interest rate	1.35%	1.90%
Fannie Mae [Member] | Minimum [Member]
Long-Term Debt [Line Items]
Medium-term notes original contractual maturity	1 year	1 year
Fannie Mae [Member] | Maximum [Member]
Long-Term Debt [Line Items]
Medium-term notes original contractual maturity	10 years	10 years
Consolidated Trusts [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 2,787,396	$ 2,760,152
Long-term debt, weighted-average interest rate	2.91%	3.02%

Derivative Instruments Derivati

Derivative Instruments Derivatives 1 - Notional and FV Position (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Asset Derivatives [Abstract]
Notional amount	$ 245,315	$ 183,204
Derivative asset, estimated fair value	1,610	1,485
Netting adjustment	(4,417)	(5,186)
Liability Derivatives [Abstract]
Notional amount	327,488	408,714
Derivative liability, estimated fair value	(904)	(614)
Netting adjustment	10,635	10,194
Table Footnote [Abstract]
Cash collateral posted for derivative instruments	6,500	5,300
Cash collateral received for derivative instruments	256	245
Risk Management Derivatives [Member]
Asset Derivatives [Abstract]
Notional amount	176,351	128,628
Derivative asset, estimated fair value	4,808	5,667
Accrued interest receivable, estimated fair value	835	749
Netting adjustment	(4,417)	(5,186)
Derivative Asset	1,226	1,230
Liability Derivatives [Abstract]
Notional amount	237,799	344,264
Derivative liability, estimated fair value	(9,752)	(9,451)
Accrued interest payable, estimated fair value	(1,220)	(1,013)
Netting adjustment	10,635	10,194
Total net risk management derivatives	(337)	(270)
Risk Management Derivatives [Member] | Pay-fixed Swap [Member]
Asset Derivatives [Abstract]
Notional amount	7,557	41,965
Derivative asset, estimated fair value	42	733
Liability Derivatives [Abstract]
Notional amount	151,810	123,557
Derivative liability, estimated fair value	(9,251)	(7,125)
Risk Management Derivatives [Member] | Receive-fixed Swap [Member]
Asset Derivatives [Abstract]
Notional amount	157,472	67,629
Derivative asset, estimated fair value	4,434	4,486
Liability Derivatives [Abstract]
Notional amount	44,981	157,272
Derivative liability, estimated fair value	(145)	(1,302)
Risk Management Derivatives [Member] | Basis Swap [Member]
Asset Derivatives [Abstract]
Notional amount	764	5,769
Derivative asset, estimated fair value	148	123
Liability Derivatives [Abstract]
Notional amount	10,600	7,100
Derivative liability, estimated fair value	(2)	(2)
Risk Management Derivatives [Member] | Foreign Currency Swap [Member]
Asset Derivatives [Abstract]
Notional amount	302	344
Derivative asset, estimated fair value	116	144
Liability Derivatives [Abstract]
Notional amount	265	273
Derivative liability, estimated fair value	(46)	(30)
Risk Management Derivatives [Member] | Pay-fixed Swaption [Member]
Asset Derivatives [Abstract]
Notional amount	6,300	11,100
Derivative asset, estimated fair value	43	57
Liability Derivatives [Abstract]
Notional amount	13,950	26,525
Derivative liability, estimated fair value	(24)	(175)
Risk Management Derivatives [Member] | Receive-fixed Swaption [Member]
Asset Derivatives [Abstract]
Notional amount	0	750
Derivative asset, estimated fair value	0	96
Liability Derivatives [Abstract]
Notional amount	14,200	29,525
Derivative liability, estimated fair value	(283)	(816)
Risk Management Derivatives [Member] | Other [Member]
Asset Derivatives [Abstract]
Notional amount	3,956	1,071
Derivative asset, estimated fair value	25	28
Liability Derivatives [Abstract]
Notional amount	1,993	12
Derivative liability, estimated fair value	(1)	(1)
Mortgage commitment derivatives [Member]
Asset Derivatives [Abstract]
Notional amount	68,964	54,576
Derivative asset, estimated fair value	384	255
Netting adjustment	0	0
Liability Derivatives [Abstract]
Notional amount	89,689	64,450
Derivative liability, estimated fair value	(567)	(344)
Netting adjustment	0	0
Mortgage commitment derivatives [Member] | Mortgage Commitments to Purchase Whole Loans [Member]
Asset Derivatives [Abstract]
Notional amount	9,595	6,157
Derivative asset, estimated fair value	57	28
Liability Derivatives [Abstract]
Notional amount	28	428
Derivative liability, estimated fair value	0	0
Mortgage commitment derivatives [Member] | Forward Contracts to Purchase Mortgage-related Securities [Member]
Asset Derivatives [Abstract]
Notional amount	57,746	43,533
Derivative asset, estimated fair value	326	223
Liability Derivatives [Abstract]
Notional amount	2,245	6,112
Derivative liability, estimated fair value	(4)	(8)
Mortgage commitment derivatives [Member] | Forward Contracts to Sell Mortgage-related Securities [Member]
Asset Derivatives [Abstract]
Notional amount	1,623	4,886
Derivative asset, estimated fair value	1	4
Liability Derivatives [Abstract]
Notional amount	87,416	57,910
Derivative liability, estimated fair value	$ (563)	$ (336)

Derivative Instruments (Narrati

Derivative Instruments (Narratives) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Aggregate fair value of all OTC derivatives with credit-risk-related contingent features that were in a net liability position	$ 3,200	$ 2,600
Aggregate fair value of collateral posted	2,800	2,400
Additional collateral required or amount required to immediately settle our positions if all of the credit-risk-related contingency features were triggered	$ 303	$ 269

Derivative Instruments Deriva79

Derivative Instruments Derivatives 2 - FV Gains and Losses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	$ (2,765)	$ (480)	$ (2,037)	$ (3,011)
Accrual of periodic settlements	5,588	5,184	16,332	14,826
Risk Management Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	(2,404)	(407)	(1,610)	(2,283)
Risk Management Derivatives [Member] | Pay-fixed Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	(4,402)	712	(3,120)	(3,755)
Accrual of periodic settlements	(895)	(939)	(2,730)	(2,755)
Risk Management Derivatives [Member] | Receive-fixed Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	2,295	(822)	2,236	2,282
Accrual of periodic settlements	620	613	2,007	1,946
Risk Management Derivatives [Member] | Basis Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	37	6	25	49
Risk Management Derivatives [Member] | Foreign Currency Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	(20)	(17)	(33)	21
Risk Management Derivatives [Member] | Pay-fixed Swaption [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	32	(53)	137	(90)
Risk Management Derivatives [Member] | Receive-fixed Swaption [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	(102)	82	(181)	(19)
Risk Management Derivatives [Member] | Other [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	22	(1)	20	(1)
Accrual of periodic settlements	9	12	29	39
Mortgage commitment derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	$ (361)	$ (73)	$ (427)	$ (728)

Earnings (Loss) Per Share (Deta

Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Net income	$ 1,960	$ 3,905	$ 8,488	$ 12,897
Less: Net income attributable to noncontrolling interest	0	0	0	(1)
Net income attributable to Fannie Mae	1,960	3,905	8,488	12,896
Dividends distributed or available for distribution to senior preferred stockholder	(2,202)	(3,999)	(8,357)	(13,403)
Net income (loss) attributable to common stockholders	$ (242)	$ (94)	$ 131	$ (507)
Weighted-average common shares outstanding, Basic	5,762	5,762	5,762	5,762
Convertible preferred stock	0	0	131	0
Weighted-average common shares outstanding, Diluted	5,762	5,762	5,893	5,762
Earnings (loss) per share, Basic (in dollars per share)	$ (0.04)	$ (0.02)	$ 0.02	$ (0.09)
Earnings (loss) per share, Diluted (in dollars per share)	$ (0.04)	$ (0.02)	$ 0.02	$ (0.09)
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) (

Segment Reporting (Narrative) (Details)	9 Months Ended
	Sep. 30, 2015segments
Segment Reporting [Abstract]
Number of Reportable Segments	3

Segment Reporting (Details)

Segment Reporting (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Net interest income (loss)	$ 5,588	$ 5,184	$ 16,332	$ 14,826
Benefit for credit losses	1,550	1,085	1,050	3,498
Net interest income (loss) after benefit for credit losses	7,138	6,269	17,382	18,324
Guaranty fee income (expense)	31	52	99	138
Investment gains (losses), net	299	171	1,155	749
Fair value gains (losses), net	(2,589)	(207)	(1,902)	(2,331)
Debt extinguishment gains (losses), net	(11)	11	0	49
Gains (losses) from partnership investments	(5)	52	235	132
Fee and other income (expense)	228	774	1,024	5,426
Administrative expenses	(952)	(706)	(2,364)	(2,075)
Foreclosed property income (expense)	(497)	(249)	(1,152)	227
TCCA Fees	(413)	(351)	(1,192)	(1,008)
Other income (expenses)	(199)	(124)	(647)	(611)
Income (loss) before federal income taxes	3,030	5,692	12,638	19,020
Provision for federal income taxes	(1,070)	(1,787)	(4,150)	(6,123)
Net income	1,960	3,905	8,488	12,897
Less: Net income attributable to noncontrolling interest	0	0	0	(1)
Net income (loss) attributable to Fannie Mae	1,960	3,905	8,488	12,896
US Treasury [Member]
Segment Reporting Information [Line Items]
TCCA Fees	(413)	(351)	(1,192)	(1,008)
Single-family [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)	66	19	93	(24)
Benefit for credit losses	1,545	1,029	967	3,377
Net interest income (loss) after benefit for credit losses	1,611	1,048	1,060	3,353
Guaranty fee income (expense)	3,145	2,945	9,277	8,708
Investment gains (losses), net	(1)	0	(2)	(1)
Fair value gains (losses), net	(4)	(4)	(8)	(11)
Debt extinguishment gains (losses), net	0	0	0	0
Gains (losses) from partnership investments	(12)	0	(27)	0
Fee and other income (expense)	98	146	571	471
Administrative expenses	(649)	(468)	(1,591)	(1,376)
Foreclosed property income (expense)	(516)	(281)	(1,183)	154
Other income (expenses)	(180)	(136)	(669)	(528)
Income (loss) before federal income taxes	3,079	2,899	6,236	9,762
Provision for federal income taxes	(1,040)	(837)	(2,040)	(2,897)
Net income				6,865
Less: Net income attributable to noncontrolling interest				0
Net income (loss) attributable to Fannie Mae	2,039	2,062	4,196	6,865
Single-family [Member] | US Treasury [Member]
Segment Reporting Information [Line Items]
TCCA Fees	(413)	(351)	(1,192)	(1,008)
Multifamily [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)	(16)	(22)	(73)	(65)
Benefit for credit losses	5	56	83	121
Net interest income (loss) after benefit for credit losses	(11)	34	10	56
Guaranty fee income (expense)	367	332	1,064	960
Investment gains (losses), net	5	8	29	50
Fair value gains (losses), net	0	0	0	0
Debt extinguishment gains (losses), net	0	0	0	0
Gains (losses) from partnership investments	7	52	262	131
Fee and other income (expense)	58	32	193	87
Administrative expenses	(109)	(77)	(280)	(225)
Foreclosed property income (expense)	19	32	31	73
Other income (expenses)	5	8	(8)	(5)
Income (loss) before federal income taxes	341	421	1,301	1,127
Provision for federal income taxes	(17)	(37)	(128)	(37)
Net income				1,090
Less: Net income attributable to noncontrolling interest				0
Net income (loss) attributable to Fannie Mae	324	384	1,173	1,090
Capital Markets [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)	1,401	1,845	4,516	5,592
Benefit for credit losses	0	0	0	0
Net interest income (loss) after benefit for credit losses	1,401	1,845	4,516	5,592
Guaranty fee income (expense)	(210)	(235)	(658)	(722)
Investment gains (losses), net	1,608	1,510	4,679	4,420
Fair value gains (losses), net	(2,697)	(335)	(2,112)	(2,770)
Debt extinguishment gains (losses), net	(25)	(3)	(30)	31
Gains (losses) from partnership investments	0	0	0	0
Fee and other income (expense)	83	579	288	4,848
Administrative expenses	(194)	(161)	(493)	(474)
Foreclosed property income (expense)	0	0	0	0
Other income (expenses)	24	(5)	18	(70)
Income (loss) before federal income taxes	(10)	3,195	6,208	10,855
Provision for federal income taxes	(13)	(913)	(1,982)	(3,189)
Net income				7,666
Less: Net income attributable to noncontrolling interest				0
Net income (loss) attributable to Fannie Mae	(23)	2,282	4,226	7,666
Consolidated Trusts [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)	3,901	3,088	11,039	8,525
Benefit for credit losses	0	0	0	0
Net interest income (loss) after benefit for credit losses	3,901	3,088	11,039	8,525
Guaranty fee income (expense)	(2,024)	(1,488)	(5,929)	(4,367)
Investment gains (losses), net	(187)	21	(664)	(141)
Fair value gains (losses), net	32	13	37	232
Debt extinguishment gains (losses), net	14	14	30	18
Gains (losses) from partnership investments	0	0	0	0
Fee and other income (expense)	(80)	(71)	(249)	(242)
Administrative expenses	0	0	0	0
Foreclosed property income (expense)	0	0	0	0
Other income (expenses)	(93)	0	(93)	0
Income (loss) before federal income taxes	1,563	1,577	4,171	4,025
Provision for federal income taxes	0	0	0	0
Net income				4,025
Less: Net income attributable to noncontrolling interest				0
Net income (loss) attributable to Fannie Mae	1,563	1,577	4,171	4,025
Eliminations/Adjustments [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)	236	254	757	798
Benefit for credit losses	0	0	0	0
Net interest income (loss) after benefit for credit losses	236	254	757	798
Guaranty fee income (expense)	(1,247)	(1,502)	(3,655)	(4,441)
Investment gains (losses), net	(1,126)	(1,368)	(2,887)	(3,579)
Fair value gains (losses), net	80	119	181	218
Debt extinguishment gains (losses), net	0	0	0	0
Gains (losses) from partnership investments	0	0	0	1
Fee and other income (expense)	69	88	221	262
Administrative expenses	0	0	0	0
Foreclosed property income (expense)	0	0	0	0
Other income (expenses)	45	9	105	(8)
Income (loss) before federal income taxes	(1,943)	(2,400)	(5,278)	(6,749)
Provision for federal income taxes	0	0	0	0
Net income				(6,749)
Less: Net income attributable to noncontrolling interest				(1)
Net income (loss) attributable to Fannie Mae	$ (1,943)	$ (2,400)	$ (5,278)	$ (6,750)

Equity Activity in OCI (Details

Equity Activity in OCI (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Equity [Abstract]
Net income	$ 1,960	$ 3,905	$ 8,488	$ 12,897
Other comprehensive (loss) income, net of tax effect:
Changes in net unrealized gains on AFS securities (net of tax of $58 and $61, respectively for the three months ended and net of tax of $89 and $364, respectively, for the nine months ended)	(107)	113	(164)	675
Reclassification adjustment for OTTI recognized in net income (net of tax of $2, for the three months ended and net of tax of $66 and $28, respectively, for the nine months ended)	3	4	121	52
Reclassification adjustment for gains on AFS securities included in net income (net of tax of $32 and $29, respectively, for the three months ended and net of tax of $265 and $133, respectively, for the nine months ended)	(73)	(54)	(505)	(247)
Other	430	32	428	32
Total other comprehensive income (loss)	253	95	(120)	512
Total comprehensive income	2,213	4,000	8,368	13,409
Other Comprehensive (Income) Loss Parenthetical Disclosures [Abstract]
Changes in net unrealized gains on AFS securities, tax	58	61	89	364
Reclassification adjustment for OTTI recognized in net income, tax	2	2	66	28
Reclassification adjustment for gains on AFS securities included in net income, tax	$ 32	$ 29	$ 265	$ 133

Equity AOCI (Details)

Equity AOCI (Details) - USD ($) $ in Millions	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Equity [Abstract]
Net unrealized gains on AFS securities for which we have not recorded OTTI, net of tax	$ 551		$ 592
Net unrealized gains on AFS securities for which we have recorded OTTI, net of tax	1,022		1,529
Prior service credit cost and actuarial gain (losses), net of amortization, net of tax	39		(358)
Other gains (losses)	1		(30)
Accumulated other comprehensive income	$ 1,613	$ 1,360	$ 1,733	$ 1,715	$ 1,620	$ 1,203

Equity Changes in AOCI (Details

Equity Changes in AOCI (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	$ 1,360	$ 1,620	$ 1,733	$ 1,203
OCI before reclassifications	(101)	145	(158)	707
Amounts reclassified from OCI	354	(50)	38	(195)
Total other comprehensive income (loss)	253	95	(120)	512
Ending balance	1,613	1,715	1,613	1,715
Available-for-Sale Securities [Member]
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	1,750	2,044	2,121	1,627
OCI before reclassifications	(107)	113	(164)	675
Amounts reclassified from OCI	(70)	(50)	(384)	(195)
Total other comprehensive income (loss)	(177)	63	(548)	480
Ending balance	1,573	2,107	1,573	2,107
Accumulated Other Comprehensive Income (Loss), Other [Member]
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(390)	(424)	(388)	(424)
OCI before reclassifications	6	32	6	32
Amounts reclassified from OCI	424	0	422	0
Total other comprehensive income (loss)	430	32	428	32
Ending balance	$ 40	$ (392)	$ 40	$ (392)

Risk Characteristics - SF (Deta

Risk Characteristics - SF (Details) - Single-family [Member]	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Guaranty Book of Business [Member] | Conventional Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30 days delinquent, percentage (unpaid principal balance)	1.29%	1.27%
60 days delinquent, percentage (unpaid principal balance)	0.36%	0.38%
Seriously delinquent, percentage (unpaid principal balance)	1.64%	1.99%
30 days delinquent, percentage (loan count)	1.48%	1.47%
60 days delinquent, percentage (loan count)	0.40%	0.43%
Seriously delinquent, percentage (loan count)	1.59%	1.89%
Percentage of loans with detailed loan level information	99.00%	99.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | 2005
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent, percentage (loan count)	5.66%	6.18%
Percentage of book of business	2.00%	3.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | 2006
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent, percentage (loan count)	8.58%	9.61%
Percentage of book of business	3.00%	3.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | 2007
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent, percentage (loan count)	9.80%	10.79%
Percentage of book of business	4.00%	4.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | 2008
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent, percentage (loan count)	5.86%	6.27%
Percentage of book of business	2.00%	2.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | All other vintages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent, percentage (loan count)	0.78%	0.88%
Percentage of book of business	89.00%	88.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | Alt-A
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent, percentage (loan count)	6.75%	7.77%
Percentage of book of business	4.00%	4.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | California
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent, percentage (loan count)	0.60%	0.70%
Percentage of book of business	20.00%	20.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | Florida
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent, percentage (loan count)	3.11%	4.42%
Percentage of book of business	6.00%	6.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | Illinois
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent, percentage (loan count)	1.95%	2.36%
Percentage of book of business	4.00%	4.00%
Guaranty Book of Business [Member] | Conventional Loan [Member] | New Jersey
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent, percentage (loan count)	5.01%	5.78%
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 (loan count)	3.67%	4.17%
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 (loan count)	1.33%	1.52%
Percentage of book of business	61.00%	61.00%
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 (loan count)	10.71%	10.98%
Percentage of book of business	3.00%	5.00%
Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Serious delinquency, days past due	90 days	90 days

Risk Characteristics - MF (Deta

Risk Characteristics - MF (Details) - Multifamily [Member]	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
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 (unpaid principal balance)	0.04%	0.04%
Seriously delinquent, percentage (unpaid principal balance)	0.05%	0.05%
Percentage of loans with detailed loan level information	99.00%	99.00%
Guaranty Book of Business [Member] | Current Debt Service Coverage Ratio Less Than 1.0 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	2.00%	3.00%
Loans seriously delinquent, percentage by unpaid principal balance	0.87%	0.83%
Guaranty Book of Business [Member] | Original Loan to Value Ratio Greater than 80% [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	3.00%	3.00%
Loans seriously delinquent, percentage by unpaid principal balance	0.03%	0.31%
Guaranty Book of Business [Member] | Original Loan to Value Ratio Less than or Equal to 80% [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	97.00%	97.00%
Loans seriously delinquent, percentage by unpaid principal balance	0.06%	0.04%

Other Concentrations (Details)

Other Concentrations (Details) $ in Millions	Sep. 30, 2015USD ($)servicersinsurers	Apr. 30, 2015	Mar. 31, 2015	Dec. 31, 2014USD ($)servicersinsurers
Concentration Risk [Line Items]
Estimated benefit included in total loss reserves	$ 2,300			$ 4,100
Receivable from claims on insured, defaulted loans excluding government insured loans	1,200			1,400
Allowance for mortgage insurance receivable	795			799
Mortgage Sellers and Servicers [Member]
Concentration Risk [Line Items]
Receivable from claims on insured, defaulted loans excluding government insured loans	$ 280			$ 269
Single-family [Member] | PMI Mortgage Insurance Co. [Member]
Concentration Risk [Line Items]
Percentage of mortgage guaranty insurance policy claims to be paid by insurer		70.00%	67.00%
Guaranty Book of Business [Member] | 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	4			4
Number of mortgage Insurers publicly disclosed credit quality deterioration | insurers	3
Guaranty Book of Business [Member] | Single-family [Member] | Unpaid Principal Balance [Member]
Concentration Risk [Line Items]
Mortgage insurance coverage risk in force	$ 115,700			$ 109,600
Mortgage insurance coverage risk in force as percentage	4.00%			4.00%
Primary mortgage insurance coverage risk in force	$ 114,900			$ 108,700
Pool mortgage insurance coverage risk in force	$ 770			$ 852
Guaranty Book of Business [Member] | Single-family [Member] | Unpaid Principal Balance [Member] | Credit Concentration Risk [Member] | Largest Mortgage Servicers, Including Their Affiliates [Member]
Concentration Risk [Line Items]
Percentage of concentration risk	44.00%			46.00%
Guaranty Book of Business [Member] | Single-family [Member] | Unpaid Principal Balance [Member] | Insurance Service Provider Concentration Risk [Member]
Concentration Risk [Line Items]
Percentage of concentration risk	9.00%
Mortgage insurance coverage risk in force, insurers with credit quality deterioration	$ 10,600
Guaranty Book of Business [Member] | Single-family [Member] | Unpaid Principal Balance [Member] | Insurance Service Provider Concentration Risk [Member] | Mortgage Insurance Companies [Member]
Concentration Risk [Line Items]
Percentage of concentration risk	79.00%			79.00%
Guaranty Book of Business [Member] | Multifamily [Member]
Concentration Risk [Line Items]
Number of mortgage servicers, including their affiliates, which serviced the majority of our guaranty book of business | servicers	10			10
Guaranty Book of Business [Member] | Multifamily [Member] | Unpaid Principal Balance [Member] | Credit Concentration Risk [Member] | Largest Mortgage Servicers, Including Their Affiliates [Member]
Concentration Risk [Line Items]
Percentage of concentration risk	69.00%			67.00%

Netting Arrangements (Details)

Netting Arrangements (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Assets
Derivative assets, gross amount	$ 6,002	$ 6,643
Derivative assets, gross amount offset	(4,417)	(5,186)
Derivative assets, net amount presented in the condensed consolidated balance sheets	1,585	1,457
Derivative assets, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, financial instruments	(189)	(116)
Derivative assets, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, collateral	(2)	(40)
Derivative assets, net amount	1,394	1,301
Securities purchased under agreements to resell or similar arrangements, gross amount	42,100	47,550
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 the condensed consolidated balance sheets	42,100	47,550
Securities purchased under agreements to resell, under master netting arrangement, amounts not offset in the 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 the condensed consolidated balance sheets, collateral	(42,100)	(47,550)
Securities purchased under agreements to resell or similar arrangements, net amount	0	0
Total assets, gross amount	48,102	54,193
Total assets, gross amount offset	(4,417)	(5,186)
Total assets, net amount presented in the condensed consolidated balance sheets	43,685	49,007
Total assets, under master netting arrangements, not offset in the condensed consolidated balance sheets, financial instruments	(189)	(116)
Total assets, under master netting arrangements, not offset in the condensed consolidated balance sheets, collateral	(42,102)	(47,590)
Total assets, net amount	1,394	1,301
Liabilities:
Derivative liabilities, gross amount	(11,538)	(10,807)
Derivative liabilities, gross amount offset	10,635	10,194
Derivative liabilities, net amount presented in the condensed consolidated balance sheets	(903)	(613)
Derivative liabilities, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, financial instruments	189	116
Derivative liabilities, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, collateral	7	0
Derivative liabilities, net amount	(707)	(497)
Securities sold under agreements to repurchase or similar arrangements, gross amount	(118)	(50)
Securities sold under agreements to repurchase or similar arrangements, gross amount offset	0	0
Securities sold under agreements to repurchase or similar arrangements, net amount presented in the condensed consolidated balance sheets	(118)	(50)
Securities sold under agreements to repurchase or similar arrangements, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, financial instruments	0	0
Securities sold under agreements to repurchase or similar arrangements, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, collateral	118	50
Securities sold under agreements to repurchase or similar arrangements, net amount	0	0
Total liabilities, gross amount	(11,656)	(10,857)
Total liabilities, gross amount offset	10,635	10,194
Total liabilities, net amount presented in the condensed consolidated balance sheets	(1,021)	(663)
Total liabilities, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, financial instruments	189	116
Total liabilities, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, collateral	125	50
Total liabilities, net amount	(707)	(497)
Risk Management Derivatives [Member]
Assets
Derivative assets, gross amount offset	(4,417)	(5,186)
Liabilities:
Derivative liabilities, gross amount offset	10,635	10,194
Risk Management Derivatives [Member] | OTC Risk Management Derivatives [Member]
Assets
Derivative assets, gross amount	4,494	5,461
Derivative assets, gross amount offset	(4,487)	(5,428)
Derivative assets, net amount presented in the condensed consolidated balance sheets	7	33
Derivative assets, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, financial instruments	0	0
Derivative assets, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, collateral	0	(33)
Derivative assets, net amount	7	0
Liabilities:
Derivative liabilities, gross amount	(7,417)	(7,836)
Derivative liabilities, gross amount offset	7,082	7,567
Derivative liabilities, net amount presented in the condensed consolidated balance sheets	(335)	(269)
Derivative liabilities, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, financial instruments	0	0
Derivative liabilities, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, collateral	0	0
Derivative liabilities, net amount	(335)	(269)
Risk Management Derivatives [Member] | Cleared Risk Management Derivatives [Member]
Assets
Derivative assets, gross amount	1,124	927
Derivative assets, gross amount offset	70	242
Derivative assets, net amount presented in the condensed consolidated balance sheets	1,194	1,169
Derivative assets, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, financial instruments	0	0
Derivative assets, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, collateral	0	0
Derivative assets, net amount	1,194	1,169
Liabilities:
Derivative liabilities, gross amount	(3,554)	(2,627)
Derivative liabilities, gross amount offset	3,553	2,627
Derivative liabilities, net amount presented in the condensed consolidated balance sheets	(1)	0
Derivative liabilities, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, financial instruments	0	0
Derivative liabilities, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, collateral	1	0
Derivative liabilities, net amount	0	0
Mortgage commitment derivatives [Member]
Assets
Derivative assets, gross amount	384	255
Derivative assets, gross amount offset	0	0
Derivative assets, net amount presented in the condensed consolidated balance sheets	384	255
Derivative assets, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, financial instruments	(189)	(116)
Derivative assets, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, collateral	(2)	(7)
Derivative assets, net amount	193	132
Liabilities:
Derivative liabilities, gross amount	(567)	(344)
Derivative liabilities, gross amount offset	0	0
Derivative liabilities, net amount presented in the condensed consolidated balance sheets	(567)	(344)
Derivative liabilities, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, financial instruments	189	116
Derivative liabilities, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, collateral	6	0
Derivative liabilities, net amount	$ (372)	$ (228)

Netting Arrangements Narratives

Netting Arrangements Narratives (Details) - USD ($)	Sep. 30, 2015	Dec. 31, 2014
Derivative [Line Items]
Derivative assets not subject to enforceable master netting arrangement	$ 25,000,000	$ 28,000,000
Derivative liabilities not subject to enforceable master netting arrangement	1,000,000	1,000,000
Cash and Cash Equivalents [Member]
Derivative [Line Items]
Securities purchased under agreements to resell or similar arrangements	15,500,000,000	16,600,000,000
Securities purchased under agreements to resell [Member]
Derivative [Line Items]
Fair value of non-cash collateral accepted	42,200,000,000	47,600,000,000
Fair value of non-cash collateral accepted that can be sold or repledged	37,900,000,000	41,900,000,000
Fair value of non-cash collateral accepted as collateral that have been sold or repledged	0	0
Securities sold under agreements to repurchase [Member]
Derivative [Line Items]
Fair value of non-cash collateral pledged	118,000,000	50,000,000
OTC Risk Management Derivatives [Member]
Derivative [Line Items]
Fair value of non-cash collateral accepted		$ 51,000,000
Cleared Risk Management Derivatives [Member]
Derivative [Line Items]
Fair value of non-cash collateral pledged that can be sold or repledged	$ 136,000,000

Fair Value Levels Hierarchy (De

Fair Value Levels Hierarchy (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Assets [Abstract]
Mortgage loans held for investment, at fair value	$ 14,605	$ 15,629
Other assets [Abstract]
Derivative assets, gross amount offset	(4,417)	(5,186)
Other liabilities [Abstract]
Derivative liabilities, gross amount offset	(10,635)	(10,194)
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	9,975	6,403
Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	23,143	19,483
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets [Abstract]
Trading Securities	26,961	19,466
Available-for-sale securities	0	0
Mortgage loans held for investment, at fair value	0	0
Total assets at fair value	61,657	57,431
Other assets [Abstract]
Derivatives assets at fair value	0	0
Liabilities [Abstract]
Total liabilities at fair value	0	0
Other liabilities [Abstract]
Derivative liabilities at fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fannie Mae [Member]
Assets [Abstract]
Mortgage loans held for investment, at fair value	0	0
Liabilities [Abstract]
Long-term debt, fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Consolidated Trusts [Member]
Assets [Abstract]
Mortgage loans held for investment, at fair value	0	0
Liabilities [Abstract]
Long-term debt, fair value	0	0
Significant Other Observable Inputs (Level 2) [Member]
Assets [Abstract]
Trading Securities	9,458	9,008
Available-for-sale securities	12,455	15,574
Mortgage loans held for investment, at fair value	2,701,802	2,687,759
Total assets at fair value	2,776,652	2,771,628
Other assets [Abstract]
Derivatives assets at fair value	5,830	6,489
Liabilities [Abstract]
Total liabilities at fair value	3,268,718	3,299,289
Other liabilities [Abstract]
Derivative liabilities at fair value	11,402	10,671
Significant Other Observable Inputs (Level 2) [Member] | Fannie Mae [Member]
Assets [Abstract]
Mortgage loans held for investment, at fair value	26,358	29,896
Liabilities [Abstract]
Long-term debt, fair value	334,007	367,703
Significant Other Observable Inputs (Level 2) [Member] | Consolidated Trusts [Member]
Assets [Abstract]
Mortgage loans held for investment, at fair value	2,675,444	2,657,863
Liabilities [Abstract]
Long-term debt, fair value	2,827,733	2,815,843
Significant Unobservable Inputs (Level 3) [Member]
Assets [Abstract]
Trading Securities	1,590	3,030
Available-for-sale securities	9,552	15,080
Mortgage loans held for investment, at fair value	386,291	400,327
Total assets at fair value	402,365	419,874
Other assets [Abstract]
Derivatives assets at fair value	197	182
Liabilities [Abstract]
Total liabilities at fair value	30,414	23,592
Other liabilities [Abstract]
Derivative liabilities at fair value	137	137
Significant Unobservable Inputs (Level 3) [Member] | Fannie Mae [Member]
Assets [Abstract]
Mortgage loans held for investment, at fair value	201,369	217,064
Liabilities [Abstract]
Long-term debt, fair value	931	982
Significant Unobservable Inputs (Level 3) [Member] | Consolidated Trusts [Member]
Assets [Abstract]
Mortgage loans held for investment, at fair value	184,922	183,263
Liabilities [Abstract]
Long-term debt, fair value	26,613	19,334
Recurring Fair Value Measurements [Member]
Assets [Abstract]
Trading Securities	38,009	31,504
Available-for-sale securities	22,007	30,654
Mortgage loans held for investment, at fair value	14,605	15,629
Total assets at fair value	76,231	79,272
Other assets [Abstract]
Derivatives assets at fair value	1,610	1,485
Derivative assets, gross amount offset	(4,417)	(5,186)
Liabilities [Abstract]
Long-term debt, fair value	33,118	25,886
Total liabilities at fair value	34,022	26,500
Other liabilities [Abstract]
Derivative liabilities at fair value	904	614
Derivative liabilities, gross amount offset	(10,635)	(10,194)
Recurring Fair Value Measurements [Member] | Swaps [Member]
Other assets [Abstract]
Derivatives assets at fair value	5,575	6,235
Other liabilities [Abstract]
Derivative liabilities at fair value	10,664	9,472
Recurring Fair Value Measurements [Member] | Swaptions [Member]
Other assets [Abstract]
Derivatives assets at fair value	43	153
Other liabilities [Abstract]
Derivative liabilities at fair value	307	991
Recurring Fair Value Measurements [Member] | Other [Member]
Other assets [Abstract]
Derivatives assets at fair value	25	28
Other liabilities [Abstract]
Derivative liabilities at fair value	1	1
Recurring Fair Value Measurements [Member] | Mortgage commitment derivatives [Member]
Other assets [Abstract]
Derivatives assets at fair value	384	255
Other liabilities [Abstract]
Derivative liabilities at fair value	567	344
Recurring Fair Value Measurements [Member] | Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	9,975	6,403
Recurring Fair Value Measurements [Member] | Fannie Mae [Member] | Senior Floating [Member]
Liabilities [Abstract]
Long-term debt, fair value	9,975	6,403
Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	23,143	19,483
Recurring Fair Value Measurements [Member] | Fannie Mae [Member]
Assets [Abstract]
Trading Securities	5,097	4,940
Available-for-sale securities	4,282	5,639
Recurring Fair Value Measurements [Member] | Freddie Mac [Member]
Assets [Abstract]
Trading Securities	1,474	1,369
Available-for-sale securities	4,599	5,528
Recurring Fair Value Measurements [Member] | Ginnie Mae [Member]
Assets [Abstract]
Trading Securities	353	166
Available-for-sale securities	413	476
Recurring Fair Value Measurements [Member] | Alt-A private-label securities [Member]
Assets [Abstract]
Trading Securities	451	920
Available-for-sale securities	3,349	5,678
Recurring Fair Value Measurements [Member] | Subprime private-label securities [Member]
Assets [Abstract]
Trading Securities	696	1,307
Available-for-sale securities	3,677	5,240
Recurring Fair Value Measurements [Member] | CMBS [Member]
Assets [Abstract]
Trading Securities	2,398	2,515
Available-for-sale securities	1,309	1,397
Recurring Fair Value Measurements [Member] | Mortgage revenue bonds [Member]
Assets [Abstract]
Trading Securities	579	722
Available-for-sale securities	2,933	4,023
Recurring Fair Value Measurements [Member] | Other [Member]
Assets [Abstract]
Trading Securities		99
Available-for-sale securities	1,445	2,673
Recurring Fair Value Measurements [Member] | U.S. Treasury securities [Member]
Assets [Abstract]
Trading Securities	26,961	19,466
Recurring Fair Value Measurements [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets [Abstract]
Trading Securities	26,961	19,466
Available-for-sale securities	0	0
Mortgage loans held for investment, at fair value	0	0
Total assets at fair value	26,961	19,466
Other assets [Abstract]
Derivatives assets at fair value	0	0
Liabilities [Abstract]
Long-term debt, fair value	0	0
Total liabilities 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] | 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] | Freddie Mac [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] | Ginnie 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] | Alt-A 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] | 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]
Trading Securities		0
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	26,961	19,466
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets [Abstract]
Trading Securities	9,458	9,008
Available-for-sale securities	12,455	15,574
Mortgage loans held for investment, at fair value	13,105	13,796
Total assets at fair value	40,848	44,867
Other assets [Abstract]
Derivatives assets at fair value	5,830	6,489
Liabilities [Abstract]
Long-term debt, fair value	32,178	24,996
Total liabilities at fair value	43,580	35,667
Other liabilities [Abstract]
Derivative liabilities at fair value	11,402	10,671
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Swaps [Member]
Other assets [Abstract]
Derivatives assets at fair value	5,417	6,085
Other liabilities [Abstract]
Derivative liabilities at fair value	10,531	9,339
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Swaptions [Member]
Other assets [Abstract]
Derivatives assets at fair value	39	153
Other liabilities [Abstract]
Derivative liabilities at fair value	307	991
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	374	251
Other liabilities [Abstract]
Derivative liabilities at fair value	564	341
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	9,606	6,040
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	9,606	6,040
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	22,572	18,956
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fannie Mae [Member]
Assets [Abstract]
Trading Securities	5,097	4,635
Available-for-sale securities	4,282	5,639
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Freddie Mac [Member]
Assets [Abstract]
Trading Securities	1,474	1,369
Available-for-sale securities	4,595	5,522
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Ginnie Mae [Member]
Assets [Abstract]
Trading Securities	353	166
Available-for-sale securities	413	476
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Alt-A private-label securities [Member]
Assets [Abstract]
Trading Securities	136	323
Available-for-sale securities	1,855	2,538
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Subprime private-label securities [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] | CMBS [Member]
Assets [Abstract]
Trading Securities	2,398	2,515
Available-for-sale securities	1,309	1,397
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]
Trading Securities		0
Available-for-sale securities	1	2
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	1,590	3,030
Available-for-sale securities	9,552	15,080
Mortgage loans held for investment, at fair value	1,500	1,833
Total assets at fair value	12,839	20,125
Other assets [Abstract]
Derivatives assets at fair value	197	182
Liabilities [Abstract]
Long-term debt, fair value	940	890
Total liabilities at fair value	1,077	1,027
Other liabilities [Abstract]
Derivative liabilities at fair value	137	137
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Swaps [Member]
Other assets [Abstract]
Derivatives assets at fair value	158	150
Other liabilities [Abstract]
Derivative liabilities at fair value	133	133
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Swaptions [Member]
Other assets [Abstract]
Derivatives assets at fair value	4	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	25	28
Other liabilities [Abstract]
Derivative liabilities at fair value	1	1
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Mortgage commitment derivatives [Member]
Other assets [Abstract]
Derivatives assets at fair value	10	4
Other liabilities [Abstract]
Derivative liabilities at fair value	3	3
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	369	363
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fannie Mae [Member] | Senior Floating [Member]
Liabilities [Abstract]
Long-term debt, fair value	369	363
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	571	527
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fannie Mae [Member]
Assets [Abstract]
Trading Securities	0	305
Available-for-sale securities	0	0
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Freddie Mac [Member]
Assets [Abstract]
Trading Securities	0	0
Available-for-sale securities	4	6
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Ginnie Mae [Member]
Assets [Abstract]
Trading Securities	0	0
Available-for-sale securities	0	0
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Alt-A private-label securities [Member]
Assets [Abstract]
Trading Securities	315	597
Available-for-sale securities	1,494	3,140
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Subprime private-label securities [Member]
Assets [Abstract]
Trading Securities	696	1,307
Available-for-sale securities	3,677	5,240
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	579	722
Available-for-sale securities	2,933	4,023
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other [Member]
Assets [Abstract]
Trading Securities		99
Available-for-sale securities	1,444	2,671
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		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Trading Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 1,645	$ 2,669	$ 3,030	$ 2,774
Total gains or (losses) (realized/unrealized) Included in Net Income	(27)	122	39	496
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	(1,067)	(264)
Issues	0	0	0	0
Settlements	(28)	(59)	(120)	(216)
Transfers out of Level 3	0	(16)	(322)	(200)
Transfers into Level 3	0	412	30	538
Ending Balance	1,590	3,128	1,590	3,128
Net unrealized gains (losses) included in net income related to assets and liabilities still held at period end	(27)	116	(22)	449
Trading Securities [Member] | Fannie Mae [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance		0	305	42
Total gains or (losses) (realized/unrealized) Included in Net Income		0	(27)	(1)
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income		0	0	0
Purchases		0	0	0
Sales		0	(2)	0
Issues		0	0	0
Settlements		0	0	(2)
Transfers out of Level 3		0	(278)	(39)
Transfers into Level 3		325	2	325
Ending Balance	0	325	0	325
Net unrealized gains (losses) included in net income related to assets and liabilities still held at period end		0	0	0
Trading Securities [Member] | Freddie Mac [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance				2
Total gains or (losses) (realized/unrealized) Included in Net Income				0
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income				0
Purchases				0
Sales				0
Issues				0
Settlements				0
Transfers out of Level 3				(2)
Transfers into Level 3				0
Ending Balance		0		0
Net unrealized gains (losses) included in net income related to assets and liabilities still held at period end				0
Trading Securities [Member] | Alt-A private-label securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	325	643	597	618
Total gains or (losses) (realized/unrealized) Included in Net Income	(3)	2	41	105
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	(267)	(23)
Issues	0	0	0	0
Settlements	(7)	(21)	(40)	(59)
Transfers out of Level 3	0	(16)	(44)	(159)
Transfers into Level 3	0	87	28	213
Ending Balance	315	695	315	695
Net unrealized gains (losses) included in net income related to assets and liabilities still held at period end	(3)	3	(3)	100
Trading Securities [Member] | Subprime private-label securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	718	1,282	1,307	1,448
Total gains or (losses) (realized/unrealized) Included in Net Income	(5)	66	38	245
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	(580)	(241)
Issues	0	0	0	0
Settlements	(17)	(32)	(69)	(136)
Transfers out of Level 3	0	0	0	0
Transfers into Level 3	0	0	0	0
Ending Balance	696	1,316	696	1,316
Net unrealized gains (losses) included in net income related to assets and liabilities still held at period end	(5)	66	(2)	209
Trading Securities [Member] | Mortgage revenue bonds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	602	643	722	565
Total gains or (losses) (realized/unrealized) Included in Net Income	(19)	53	(17)	137
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	(118)	0
Issues	0	0	0	0
Settlements	(4)	(3)	(8)	(9)
Transfers out of Level 3	0	0	0	0
Transfers into Level 3	0	0	0	0
Ending Balance	579	693	579	693
Net unrealized gains (losses) included in net income related to assets and liabilities still held at period end	(19)	46	(17)	130
Trading Securities [Member] | Other [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance		101	99	99
Total gains or (losses) (realized/unrealized) Included in Net Income		1	4	10
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income		0	0	0
Purchases		0	0	0
Sales		0	(100)	0
Issues		0	0	0
Settlements		(3)	(3)	(10)
Transfers out of Level 3		0	0	0
Transfers into Level 3		0	0	0
Ending Balance	0	99	0	99
Net unrealized gains (losses) included in net income related to assets and liabilities still held at period end		1	0	10
Available-for-sale securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	10,953	16,810	15,080	19,012
Total gains or (losses) (realized/unrealized) Included in Net Income	112	109	676	505
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	(177)	226	(467)	831
Purchases	0	0	421	0
Sales	(774)	(329)	(4,194)	(2,056)
Issues	0	0	0	0
Settlements	(587)	(850)	(1,774)	(2,603)
Transfers out of Level 3	(1)	(337)	(540)	(1,217)
Transfers into Level 3	26	268	350	1,425
Ending Balance	9,552	15,897	9,552	15,897
Net unrealized gains (losses) included in net income related to assets and liabilities still held at period end	0	0	0	0
Available-for-sale securities [Member] | Fannie Mae [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	129	2	0	7
Total gains or (losses) (realized/unrealized) Included in Net Income	0	0	0	0
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	0	0	0	0
Purchases	0	0	421	0
Sales	(122)	0	(425)	0
Issues	0	0	0	0
Settlements	(8)	0	(8)	(1)
Transfers out of Level 3	0	(2)	0	(8)
Transfers into Level 3	1	0	12	2
Ending Balance	0	0	0	0
Net unrealized gains (losses) included in net income related to assets and liabilities still held at period end	0	0	0	0
Available-for-sale securities [Member] | Freddie Mac [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	4	9	6	8
Total gains or (losses) (realized/unrealized) Included in Net Income	0	0	0	0
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issues	0	0	0	0
Settlements	0	(1)	(1)	(1)
Transfers out of Level 3	(1)	(2)	(2)	(2)
Transfers into Level 3	1	0	1	1
Ending Balance	4	6	4	6
Net unrealized gains (losses) included in net income related to assets and liabilities still held at period end	0	0	0	0
Available-for-sale securities [Member] | Alt-A private-label securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,654	3,717	3,140	3,791
Total gains or (losses) (realized/unrealized) Included in Net Income	2	15	174	131
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	(8)	(60)	(124)	(11)
Purchases	0	0	0	0
Sales	0	0	(1,108)	(320)
Issues	0	0	0	0
Settlements	(178)	(111)	(387)	(310)
Transfers out of Level 3	0	(333)	(538)	(1,207)
Transfers into Level 3	24	268	337	1,422
Ending Balance	1,494	3,496	1,494	3,496
Net unrealized gains (losses) included in net income related to assets and liabilities still held at period end	0	0	0	0
Available-for-sale securities [Member] | Subprime private-label securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	3,837	5,705	5,240	7,068
Total gains or (losses) (realized/unrealized) Included in Net Income	33	87	478	388
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	(45)	89	(277)	270
Purchases	0	0	0	0
Sales	0	(317)	(1,325)	(1,666)
Issues	0	0	0	0
Settlements	(148)	(178)	(439)	(674)
Transfers out of Level 3	0	0	0	0
Transfers into Level 3	0	0	0	0
Ending Balance	3,677	5,386	3,677	5,386
Net unrealized gains (losses) included in net income related to assets and liabilities still held at period end	0	0	0	0
Available-for-sale securities [Member] | Mortgage revenue bonds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	3,171	4,560	4,023	5,253
Total gains or (losses) (realized/unrealized) Included in Net Income	4	(4)	44	(31)
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	(29)	200	(56)	480
Purchases	0	0	0	0
Sales	(8)	(12)	(324)	(70)
Issues	0	0	0	0
Settlements	(205)	(478)	(754)	(1,366)
Transfers out of Level 3	0	0	0	0
Transfers into Level 3	0	0	0	0
Ending Balance	2,933	4,266	2,933	4,266
Net unrealized gains (losses) included in net income related to assets and liabilities still held at period end	0	0	0	0
Available-for-sale securities [Member] | Other [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	2,158	2,817	2,671	2,885
Total gains or (losses) (realized/unrealized) Included in Net Income	73	11	(20)	17
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	(95)	(3)	(10)	92
Purchases	0	0	0	0
Sales	(644)	0	(1,012)	0
Issues	0	0	0	0
Settlements	(48)	(82)	(185)	(251)
Transfers out of Level 3	0	0	0	0
Transfers into Level 3	0	0	0	0
Ending Balance	1,444	2,743	1,444	2,743
Net unrealized gains (losses) included in net income related to assets and liabilities still held at period end	0	0	0	0
Mortgage Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,595	2,531	1,833	2,704
Total gains or (losses) (realized/unrealized) Included in Net Income	9	116	47	243
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	0	0	0	0
Purchases	0	3	5	34
Sales	0	0	0	0
Issues	0	0	0	0
Settlements	(97)	(93)	(273)	(259)
Transfers out of Level 3	(77)	(750)	(331)	(1,063)
Transfers into Level 3	70	64	219	212
Ending Balance	1,500	1,871	1,500	1,871
Net unrealized gains (losses) included in net income related to assets and liabilities still held at period end	(24)	(13)	(17)	49
Net derivatives [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	4	20	45	(40)
Total gains or (losses) (realized/unrealized) Included in Net Income	79	(25)	(20)	52
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issues	0	0	0	0
Settlements	(32)	(9)	26	(25)
Transfers out of Level 3	0	0	0	(1)
Transfers into Level 3	9	5	9	5
Ending Balance	60	(9)	60	(9)
Net unrealized gains (losses) included in net income related to assets and liabilities still held at period end	28	(9)	23	14
Long-term debt [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(839)	(823)	(890)	(1,473)
Total (Losses) Gains (Realized/Unrealized) Included in Net Loss	(23)	(24)	(14)	(163)
Total Gains or (Losses) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issues	(64)	0	(64)	(751)
Settlements	18	15	43	70
Transfers out of Level 3	33	34	142	1,565
Transfers into Level 3	(65)	(26)	(157)	(72)
Ending Balance	(940)	(824)	(940)	(824)
Net Unrealized Gain (Loss) Included in Net Loss Related to Liabilities Still Held at period end	(23)	(25)	5	(115)
Long-term debt [Member] | Consolidated Trusts [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(493)	(498)	(527)	(518)
Total (Losses) Gains (Realized/Unrealized) Included in Net Loss	0	(14)	(8)	(48)
Total Gains or (Losses) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issues	(64)	0	(64)	(1)
Settlements	18	16	43	51
Transfers out of Level 3	33	34	142	100
Transfers into Level 3	(65)	(26)	(157)	(72)
Ending Balance	(571)	(488)	(571)	(488)
Net Unrealized Gain (Loss) Included in Net Loss Related to Liabilities Still Held at period end	0	(14)	11	(45)
Long-term debt [Member] | Senior Floating [Member] | Fannie Mae [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(346)	(325)	(363)	(955)
Total (Losses) Gains (Realized/Unrealized) Included in Net Loss	(23)	(10)	(6)	(115)
Total Gains or (Losses) Included in Other Comprehensive Income (Loss)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issues	0	0	0	(750)
Settlements	0	(1)	0	19
Transfers out of Level 3	0	0	0	1,465
Transfers into Level 3	0	0	0	0
Ending Balance	(369)	(336)	(369)	(336)
Net Unrealized Gain (Loss) Included in Net Loss Related to Liabilities Still Held at period end	$ (23)	$ (11)	$ (6)	$ (70)

Fair Value Level 3 Valuation In

Fair Value Level 3 Valuation Inputs (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Fair Value Inputs, Quantitative Information [Line Items]
Loans Receivable, Fair Value Disclosure	$ 14,605	$ 15,629
Derivatives	1,585	1,457
Fannie Mae [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(9,975)	(6,403)
Consolidated Trusts [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(23,143)	(19,483)
Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities	38,009	31,504
Available-for-sale securities	22,007	30,654
Loans Receivable, Fair Value Disclosure	14,605	15,629
Long-term Debt, Fair Value	(33,118)	(25,886)
Recurring Fair Value Measurements [Member] | Alt-A private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities	451	920
Available-for-sale securities	3,349	5,678
Recurring Fair Value Measurements [Member] | Subprime private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities	696	1,307
Available-for-sale securities	3,677	5,240
Recurring Fair Value Measurements [Member] | Mortgage revenue bonds [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities	579	722
Available-for-sale securities	2,933	4,023
Recurring Fair Value Measurements [Member] | Other [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities		99
Available-for-sale securities	1,445	2,673
Recurring Fair Value Measurements [Member] | Fannie Mae [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(9,975)	(6,403)
Recurring Fair Value Measurements [Member] | Fannie Mae [Member] | Senior Floating [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(9,975)	(6,403)
Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	(23,143)	(19,483)
Significant Unobservable Inputs (Level 3) [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities	1,590	3,030
Available-for-sale securities	9,552	15,080
Loans Receivable, Fair Value Disclosure	386,291	400,327
Significant Unobservable Inputs (Level 3) [Member] | Fannie Mae [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Loans Receivable, Fair Value Disclosure	201,369	217,064
Long-term Debt, Fair Value	(931)	(982)
Significant Unobservable Inputs (Level 3) [Member] | Consolidated Trusts [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Loans Receivable, Fair Value Disclosure	184,922	183,263
Long-term Debt, Fair Value	(26,613)	(19,334)
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities	1,590	3,030
Available-for-sale securities	9,552	15,080
Loans Receivable, Fair Value Disclosure	1,500	1,833
Derivatives	60	45
Long-term Debt, Fair Value	(940)	(890)
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Agency [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities		305
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Alt-A private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities	315	597
Available-for-sale securities	1,494	3,140
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Subprime private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities	696	1,307
Available-for-sale securities	3,677	5,240
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Mortgage revenue bonds [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities	579	722
Available-for-sale securities	2,933	4,023
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Other [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities		99
Available-for-sale securities	1,444	2,671
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Agency [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities		$ 130
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Agency [Member] | Trading Securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Prepayment Speed (%)		100.00%
Spreads (%)		1.846%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Agency [Member] | Trading Securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Prepayment Speed (%)		100.00%
Spreads (%)		2.195%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Agency [Member] | Trading Securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Prepayment Speed (%)		100.00%
Spreads (%)		1.975%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Alt-A private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities	64	$ 66
Available-for-sale securities	$ 598	$ 1,187
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Alt-A private-label securities [Member] | Trading Securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	1.60%	5.40%
Prepayment Speed (%)	3.70%	7.00%
Severity (%)	61.70%	48.80%
Spreads (%)	2.661%	2.648%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Alt-A private-label securities [Member] | Trading Securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	1.60%	5.40%
Prepayment Speed (%)	3.70%	7.00%
Severity (%)	61.70%	48.80%
Spreads (%)	2.661%	2.648%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Alt-A private-label securities [Member] | Trading Securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	1.60%	5.40%
Prepayment Speed (%)	3.70%	7.00%
Severity (%)	61.70%	48.80%
Spreads (%)	2.661%	2.648%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Alt-A private-label securities [Member] | Available-for-sale securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	0.40%	0.40%
Prepayment Speed (%)	0.20%	0.10%
Severity (%)	6.80%	0.20%
Spreads (%)	1.97%	1.838%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Alt-A private-label securities [Member] | Available-for-sale securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	12.20%	31.20%
Prepayment Speed (%)	31.80%	48.90%
Severity (%)	95.00%	95.00%
Spreads (%)	2.45%	2.40%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Alt-A private-label securities [Member] | Available-for-sale securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	4.30%	5.10%
Prepayment Speed (%)	14.50%	11.00%
Severity (%)	66.50%	59.60%
Spreads (%)	2.427%	2.367%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Subprime private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities	$ 479	$ 422
Available-for-sale securities	$ 2,365	$ 2,722
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Subprime private-label securities [Member] | Trading Securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	4.00%	3.50%
Prepayment Speed (%)	1.00%	1.40%
Severity (%)	41.80%	72.10%
Spreads (%)	2.75%	2.65%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Subprime private-label securities [Member] | Trading Securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	10.30%	11.80%
Prepayment Speed (%)	4.60%	5.20%
Severity (%)	95.00%	95.00%
Spreads (%)	2.80%	2.65%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Subprime private-label securities [Member] | Trading Securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	6.50%	7.20%
Prepayment Speed (%)	2.30%	2.80%
Severity (%)	75.50%	85.90%
Spreads (%)	2.754%	2.65%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Subprime private-label securities [Member] | Available-for-sale securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	0.50%	1.50%
Prepayment Speed (%)	0.30%	0.10%
Severity (%)	14.50%	1.50%
Spreads (%)	2.45%	1.55%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Subprime private-label securities [Member] | Available-for-sale securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	19.30%	37.40%
Prepayment Speed (%)	13.20%	17.70%
Severity (%)	95.00%	95.00%
Spreads (%)	2.80%	2.65%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus with Inputs [Member] | Subprime private-label securities [Member] | Available-for-sale securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	7.70%	6.30%
Prepayment Speed (%)	3.40%	2.60%
Severity (%)	78.50%	84.40%
Spreads (%)	2.737%	2.20%
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	$ 737	$ 720
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 (%)	0.00%	0.10%
Prepayment Speed (%)	2.50%	3.00%
Severity (%)	3.10%	0.40%
Spreads (%)	1.95%	2.15%
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 (%)	4.60%	6.60%
Prepayment Speed (%)	17.40%	30.40%
Severity (%)	95.00%	95.00%
Spreads (%)	4.663%	4.814%
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 (%)	3.40%	3.90%
Prepayment Speed (%)	4.50%	4.80%
Severity (%)	67.10%	62.40%
Spreads (%)	3.341%	3.206%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus without Inputs [Member] | Alt-A private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities		$ 151
Available-for-sale securities	$ 545	691
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consensus without Inputs [Member] | Subprime private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities		549
Available-for-sale securities	774	1,755
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Alt-A private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities	251
Available-for-sale securities	$ 313	$ 403
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Alt-A private-label securities [Member] | Trading Securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	1.50%
Prepayment Speed (%)	4.00%
Severity (%)	55.00%
Spreads (%)	2.225%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Alt-A private-label securities [Member] | Trading Securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	3.00%
Prepayment Speed (%)	4.00%
Severity (%)	95.00%
Spreads (%)	2.304%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Alt-A private-label securities [Member] | Trading Securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	2.70%
Prepayment Speed (%)	4.00%
Severity (%)	88.10%
Spreads (%)	2.29%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Alt-A private-label securities [Member] | Available-for-sale securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	4.00%	5.00%
Prepayment Speed (%)	3.00%	0.50%
Severity (%)	50.00%	35.10%
Spreads (%)	2.016%	1.88%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Alt-A private-label securities [Member] | Available-for-sale securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	7.00%	11.50%
Prepayment Speed (%)	10.00%	8.40%
Severity (%)	85.00%	92.40%
Spreads (%)	4.81%	3.40%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Alt-A private-label securities [Member] | Available-for-sale securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	4.50%	7.00%
Prepayment Speed (%)	5.00%	3.40%
Severity (%)	63.50%	54.20%
Spreads (%)	2.892%	2.434%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Subprime private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities	$ 169	$ 290
Available-for-sale securities	$ 265	$ 317
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Subprime private-label securities [Member] | Trading Securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	4.00%	4.30%
Prepayment Speed (%)	2.00%	2.30%
Severity (%)	60.00%	62.20%
Spreads (%)	2.03%	2.65%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Subprime private-label securities [Member] | Trading Securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	8.00%	6.20%
Prepayment Speed (%)	3.30%	4.20%
Severity (%)	78.00%	95.00%
Spreads (%)	3.00%	3.821%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Subprime private-label securities [Member] | Trading Securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	5.00%	5.20%
Prepayment Speed (%)	2.40%	3.30%
Severity (%)	65.20%	73.80%
Spreads (%)	2.257%	2.837%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Subprime private-label securities [Member] | Available-for-sale securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	5.60%	3.00%
Prepayment Speed (%)	1.00%	1.10%
Severity (%)	59.00%	28.90%
Spreads (%)	1.694%	1.55%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Subprime private-label securities [Member] | Available-for-sale securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	12.00%	12.30%
Prepayment Speed (%)	4.00%	9.00%
Severity (%)	95.00%	91.80%
Spreads (%)	3.15%	8.95%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Subprime private-label securities [Member] | Available-for-sale securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	7.80%	7.00%
Prepayment Speed (%)	1.90%	4.10%
Severity (%)	80.40%	81.20%
Spreads (%)	2.254%	2.505%
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	$ 563	$ 540
Available-for-sale securities	$ 1,607	$ 1,581
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 (%)	0.245%	0.06%
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 (%)	3.718%	3.18%
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 (%)	2.748%	2.63%
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 (%)	0.07%	(0.115%)
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 (%)	4.079%	6.202%
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 (%)	2.755%	2.514%
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	$ 550
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 (%)	0.00%
Prepayment Speed (%)	0.00%
Severity (%)	25.00%
Spreads (%)	2.45%
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 (%)	4.90%
Prepayment Speed (%)	2.00%
Severity (%)	95.00%
Spreads (%)	3.50%
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 (%)	0.20%
Prepayment Speed (%)	0.10%
Severity (%)	90.60%
Spreads (%)	3.303%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Other Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Derivatives	$ 13	$ 2
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Other Valuation Technique without Inputs [Member] | Agency [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities		22
Available-for-sale securities	4	6
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Other Valuation Technique without Inputs [Member] | Alt-A private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities		90
Available-for-sale securities	38	44
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Other Valuation Technique without Inputs [Member] | Subprime private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities	48	46
Available-for-sale securities	273	63
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Other Valuation Technique without Inputs [Member] | Mortgage revenue bonds [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities	16	21
Available-for-sale securities	200	10
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Other Valuation Technique without Inputs [Member] | Other [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	157	399
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Dealer Mark without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Derivatives	162	150
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Dealer Mark without Inputs [Member] | Other [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities		99
Available-for-sale securities		1,215
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Dealer Mark with Inputs [Member] | Mortgage revenue bonds [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities		161
Available-for-sale securities		$ 510
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Dealer Mark with Inputs [Member] | Mortgage revenue bonds [Member] | Trading Securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)		2.881%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Dealer Mark with Inputs [Member] | Mortgage revenue bonds [Member] | Trading Securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)		2.881%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Dealer Mark with Inputs [Member] | Mortgage revenue bonds [Member] | Trading Securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)		2.881%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Dealer Mark with Inputs [Member] | Mortgage revenue bonds [Member] | Available-for-sale securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)		2.228%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Dealer Mark with Inputs [Member] | Mortgage revenue bonds [Member] | Available-for-sale securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)		3.221%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Dealer Mark with Inputs [Member] | Mortgage revenue bonds [Member] | Available-for-sale securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)		2.659%
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		$ 153
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 (%)		100.00%
Spreads (%)		2.565%
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 (%)		100.00%
Spreads (%)		3.508%
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 (%)		100.00%
Spreads (%)		2.934%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor with Inputs [Member] | Alt-A private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading Securities		$ 290
Available-for-sale securities		$ 322
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor with Inputs [Member] | Alt-A private-label securities [Member] | Trading Securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		8.30%
Prepayment Speed (%)		2.90%
Severity (%)		79.50%
Spreads (%)		2.672%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor with Inputs [Member] | Alt-A private-label securities [Member] | Trading Securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		9.10%
Prepayment Speed (%)		3.20%
Severity (%)		95.00%
Spreads (%)		3.082%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor with Inputs [Member] | Alt-A private-label securities [Member] | Trading Securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		8.50%
Prepayment Speed (%)		3.10%
Severity (%)		90.40%
Spreads (%)		2.794%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor with Inputs [Member] | Alt-A private-label securities [Member] | Available-for-sale securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		0.20%
Prepayment Speed (%)		0.20%
Severity (%)		27.80%
Spreads (%)		1.90%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor with Inputs [Member] | Alt-A private-label securities [Member] | Available-for-sale securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		13.10%
Prepayment Speed (%)		20.50%
Severity (%)		89.70%
Spreads (%)		3.15%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor with Inputs [Member] | Alt-A private-label securities [Member] | Available-for-sale securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		4.60%
Prepayment Speed (%)		8.20%
Severity (%)		61.00%
Spreads (%)		2.649%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor with Inputs [Member] | Subprime private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities		$ 383
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor with Inputs [Member] | Subprime private-label securities [Member] | Available-for-sale securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		2.10%
Prepayment Speed (%)		1.50%
Severity (%)		65.40%
Spreads (%)		2.15%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor with Inputs [Member] | Subprime private-label securities [Member] | Available-for-sale securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		8.30%
Prepayment Speed (%)		3.30%
Severity (%)		95.00%
Spreads (%)		2.62%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor with Inputs [Member] | Subprime private-label securities [Member] | Available-for-sale securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		5.50%
Prepayment Speed (%)		2.10%
Severity (%)		78.50%
Spreads (%)		2.30%
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	$ 1,126	$ 1,504
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 (%)	0.07%	(0.115%)
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 (%)	3.479%	3.615%
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 (%)	0.628%	0.527%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor with Inputs [Member] | Other [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities		$ 337
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor with Inputs [Member] | Other [Member] | Available-for-sale securities [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		1.70%
Prepayment Speed (%)		3.00%
Severity (%)		4.00%
Spreads (%)		2.631%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor with Inputs [Member] | Other [Member] | Available-for-sale securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		5.00%
Prepayment Speed (%)		9.30%
Severity (%)		94.60%
Spreads (%)		4.272%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor with Inputs [Member] | Other [Member] | Available-for-sale securities [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		4.40%
Prepayment Speed (%)		3.80%
Severity (%)		69.60%
Spreads (%)		2.915%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single Vendor without Inputs [Member] | Alt-A private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities		$ 493
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		418
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Internal Model [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Derivatives	$ (115)	(107)
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-family [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Loans Receivable, Fair Value Disclosure	1,339	1,654
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-family [Member] | Consensus with Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Loans Receivable, Fair Value Disclosure	$ 258
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-family [Member] | Consensus with Inputs [Member] | Mortgage Loans [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	0.00%
Prepayment Speed (%)	3.20%
Severity (%)	20.00%
Spreads (%)	2.434%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-family [Member] | Consensus with Inputs [Member] | Mortgage Loans [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	7.60%
Prepayment Speed (%)	30.30%
Severity (%)	95.00%
Spreads (%)	2.78%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-family [Member] | Consensus with Inputs [Member] | Mortgage Loans [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	3.30%
Prepayment Speed (%)	5.90%
Severity (%)	78.80%
Spreads (%)	2.535%
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]
Loans Receivable, Fair Value Disclosure	$ 236	279
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-family [Member] | Discounted Cash Flow with Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Loans Receivable, Fair Value Disclosure		$ 402
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-family [Member] | Discounted Cash Flow with Inputs [Member] | Mortgage Loans [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		2.70%
Prepayment Speed (%)		0.10%
Severity (%)		35.50%
Spreads (%)		1.55%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-family [Member] | Discounted Cash Flow with Inputs [Member] | Mortgage Loans [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		13.10%
Prepayment Speed (%)		13.50%
Severity (%)		95.00%
Spreads (%)		6.65%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-family [Member] | Discounted Cash Flow with Inputs [Member] | Mortgage Loans [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)		5.50%
Prepayment Speed (%)		7.50%
Severity (%)		61.30%
Spreads (%)		2.274%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-family [Member] | Build-Up with inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Loans Receivable, Fair Value Disclosure	$ 107	$ 934
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-family [Member] | Build-Up with inputs [Member] | Mortgage Loans [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	0.00%	0.00%
Prepayment Speed (%)	3.00%	3.60%
Severity (%)	0.00%	3.40%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-family [Member] | Build-Up with inputs [Member] | Mortgage Loans [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	98.80%	99.00%
Prepayment Speed (%)	100.00%	99.80%
Severity (%)	100.00%	100.00%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-family [Member] | Build-Up with inputs [Member] | Mortgage Loans [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	35.70%	14.90%
Prepayment Speed (%)	10.40%	16.30%
Severity (%)	38.50%	23.70%
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]
Loans Receivable, Fair Value Disclosure	$ 667
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-family [Member] | Other Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Loans Receivable, Fair Value Disclosure	71	$ 39
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]
Loans Receivable, Fair Value Disclosure	$ 161	$ 179
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 (%)	0.61%	0.59%
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 (%)	3.342%	3.234%
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 (%)	1.611%	1.373%
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	$ (369)	$ (363)
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	(369)	(363)
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	(369)	(363)
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	(571)	(527)
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member] | Consensus with Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	$ (194)
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member] | Consensus with Inputs [Member] | Long-term debt [Member] | Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	0.00%
Prepayment Speed (%)	3.50%
Severity (%)	20.00%
Spreads (%)	2.434%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member] | Consensus with Inputs [Member] | Long-term debt [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	4.00%
Prepayment Speed (%)	30.30%
Severity (%)	95.00%
Spreads (%)	2.60%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member] | Consensus with Inputs [Member] | Long-term debt [Member] | Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	3.10%
Prepayment Speed (%)	5.40%
Severity (%)	78.00%
Spreads (%)	2.548%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member] | Consensus without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	$ (127)	(219)
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		$ (205)
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 (%)		2.70%
Prepayment Speed (%)		0.10%
Severity (%)		35.50%
Spreads (%)		0.88%
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 (%)		11.90%
Prepayment Speed (%)		100.00%
Severity (%)		95.00%
Spreads (%)		6.65%
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 (%)		4.00%
Prepayment Speed (%)		33.40%
Severity (%)		54.60%
Spreads (%)		2.494%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member] | Other Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term Debt, Fair Value	$ (250)	$ (103)

Fair Value Level 3 Valuation -

Fair Value Level 3 Valuation - Nonrecurring (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	$ 14,605	$ 15,629
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	178	169
Mortgage loans held for investment, at fair value	2,701,802	2,687,759
Total assets at fair value	2,776,652	2,771,628
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	3,796	169
Mortgage loans held for investment, at fair value	386,291	400,327
Total assets at fair value	402,365	419,874
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	21	93
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	2,684	110
Total assets at fair value	$ 14,929	$ 22,416
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	75.00%	77.00%
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	$ 2,251	$ 110
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	431	0
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other 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	0
Other assets	$ 27	$ 45
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] | Single-family [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	$ 8,585	$ 16,714
Acquired property, net	3,214	4,782
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Single-family [Member] | Other Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	0	60
Acquired property, net	122	191
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	8,585	16,654
Acquired property, net	970	1,045
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	620	864
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	637	1,173
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	865	1,509
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	386	625
Acquired property, net	33	140
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Multifamily [Member] | Other Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	7	0
Acquired property, net	2	13
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	90	45
Acquired property, net	31	127
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	$ 289	$ 580

Fair Value Fair Value of Financ

Fair Value Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Fair Value Measurement [Domain]
Financial assets [Abstract]
Derivative assets, gross amount offset	$ (4,417)	$ (5,186)
Financial liabilities [Abstract]
Derivative liabilities, gross amount offset	(10,635)	(10,194)
Mortgage loans held for investment, at fair value	14,605	15,629
Derivative assets, gross amount offset	(4,417)	(5,186)
Derivative liabilities, gross amount offset	(10,635)	(10,194)
HARP loans [Member]
Financial liabilities [Abstract]
Loans Receivable Refinanced under Home Affordable Refinance Program, Fair Value Disclosure	292,000	314,000
Fair Value Estimation Process [Member] | HARP loans [Member]
Financial liabilities [Abstract]
Change In Estimated Fair Value Resulting From Change In Principal Market	1,400	3,300
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets [Abstract]
Cash and cash equivalents and restricted cash	34,696	37,965
Federal funds sold and securities purchased under agreements to resell or similar arrangements	0	0
Trading Securities	26,961	19,466
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	61,657	57,431
Financial liabilities [Abstract]
Federal funds purchased and securities sold under agreements to repurchase	0	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	15,500	16,600
Federal funds sold and securities purchased under agreements to resell or similar arrangements	26,600	30,950
Trading Securities	9,458	9,008
Available-for-sale securities	12,455	15,574
Mortgage loans held for sale	178	169
Mortgage loans held for investment, at fair value	2,701,802	2,687,759
Advances to lenders	4,829	5,079
Derivatives assets at fair value	5,830	6,489
Guaranty assets and buy-ups	0	0
Total financial assets	2,776,652	2,771,628
Financial liabilities [Abstract]
Federal funds purchased and securities sold under agreements to repurchase	118	50
Derivative liabilities at fair value	11,402	10,671
Guaranty obligations	0	0
Total financial liabilities	3,268,718	3,299,289
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	1,590	3,030
Available-for-sale securities	9,552	15,080
Mortgage loans held for sale	3,796	169
Mortgage loans held for investment, at fair value	386,291	400,327
Advances to lenders	412	470
Derivatives assets at fair value	197	182
Guaranty assets and buy-ups	527	616
Total financial assets	402,365	419,874
Financial liabilities [Abstract]
Federal funds purchased and securities sold under agreements to repurchase	0	0
Derivative liabilities at fair value	137	137
Guaranty obligations	1,342	1,579
Total financial liabilities	30,414	23,592
Carrying Value [Member]
Financial assets [Abstract]
Cash and cash equivalents and restricted cash	50,196	54,565
Federal funds sold and securities purchased under agreements to resell or similar arrangements	26,600	30,950
Trading Securities	38,009	31,504
Available-for-sale securities	22,007	30,654
Mortgage loans held for sale	3,716	331
Mortgage loans held for investment, at fair value	3,016,740	3,019,163
Advances to lenders	5,253	5,559
Derivatives assets at fair value	1,610	1,485
Guaranty assets and buy-ups	189	210
Total financial assets	3,164,320	3,174,421
Financial liabilities [Abstract]
Federal funds purchased and securities sold under agreements to repurchase	118	50
Derivative liabilities at fair value	904	614
Guaranty obligations	338	382
Total financial liabilities	3,207,605	3,223,201
Estimated Fair Value [Member]
Financial assets [Abstract]
Cash and cash equivalents and restricted cash	50,196	54,565
Federal funds sold and securities purchased under agreements to resell or similar arrangements	26,600	30,950
Trading Securities	38,009	31,504
Available-for-sale securities	22,007	30,654
Mortgage loans held for sale	3,974	338
Mortgage loans held for investment, at fair value	3,088,093	3,088,086
Advances to lenders	5,241	5,549
Derivatives assets at fair value	1,610	1,485
Guaranty assets and buy-ups	527	616
Total financial assets	3,236,257	3,243,747
Financial liabilities [Abstract]
Federal funds purchased and securities sold under agreements to repurchase	118	50
Derivative liabilities at fair value	904	614
Guaranty obligations	1,342	1,579
Total financial liabilities	3,288,497	3,312,687
Fannie Mae [Member]
Financial liabilities [Abstract]
Long-term debt	9,975	6,403
Fannie Mae [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	0	0
Financial liabilities [Abstract]
Short-term debt	0	0
Long-term debt	0	0
Fannie Mae [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	26,358	29,896
Financial liabilities [Abstract]
Short-term debt	95,458	105,022
Long-term debt	334,007	367,703
Fannie Mae [Member] | Significant Unobservable Inputs (Level 3) [Member]
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	201,369	217,064
Financial liabilities [Abstract]
Short-term debt	0	0
Long-term debt	931	982
Fannie Mae [Member] | Carrying Value [Member]
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	213,639	239,243
Financial liabilities [Abstract]
Short-term debt	95,427	105,012
Long-term debt	322,031	355,431
Fannie Mae [Member] | Estimated Fair Value [Member]
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	227,727	246,960
Financial liabilities [Abstract]
Short-term debt	95,458	105,022
Long-term debt	334,938	368,685
Consolidated Trusts [Member]
Financial liabilities [Abstract]
Long-term debt	23,143	19,483
Consolidated Trusts [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	0	0
Financial liabilities [Abstract]
Short-term debt	0	0
Long-term debt	0	0
Consolidated Trusts [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	2,675,444	2,657,863
Financial liabilities [Abstract]
Short-term debt	0	0
Long-term debt	2,827,733	2,815,843
Consolidated Trusts [Member] | Significant Unobservable Inputs (Level 3) [Member]
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	184,922	183,263
Financial liabilities [Abstract]
Short-term debt	1,391	1,560
Long-term debt	26,613	19,334
Consolidated Trusts [Member] | Carrying Value [Member]
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	2,803,101	2,779,920
Financial liabilities [Abstract]
Short-term debt	1,391	1,560
Long-term debt	2,787,396	2,760,152
Consolidated Trusts [Member] | Estimated Fair Value [Member]
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	2,860,366	2,841,126
Financial liabilities [Abstract]
Short-term debt	1,391	1,560
Long-term debt	$ 2,854,346	$ 2,835,177

Fair Value Fair Value Option (D

Fair Value Fair Value Option (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Fair Value, Option, Quantitative Disclosures [Line Items]
Mortgage loans held for investment, at fair value	$ 14,605	$ 15,629
Fair value of nonaccrual loans	241	240
Difference between unpaid principal balance and the fair value of nonaccrual loans	60	75
Fair value of loans that are 90 days or more past due	269	271
Difference between unpaid principal balance and the fair value of these 90 days or more past due loans	$ 52	$ 78
Single-family [Member] | Minimum [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Serious delinquency, days past due	90 days	90 days
Consolidated Trusts [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Long-term debt, fair value	$ 23,143	$ 19,483
Fannie Mae [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Long-term debt, fair value	9,975	6,403
Loans [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Mortgage loans held for investment, at fair value	14,605	15,629
Loans, unpaid principal balance	14,019	15,001
Long-term debt [Member] | Consolidated Trusts [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Long-term debt, fair value	23,143	19,483
Long-term debt, unpaid principal balance	21,038	17,810
Long-term debt [Member] | Fannie Mae [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Long-term debt, fair value	9,975	6,403
Long-term debt, unpaid principal balance	$ 10,104	$ 6,512

Fair Value Changes in FV under

Fair Value Changes in FV under the FV Option (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Fair Value, Option, Quantitative Disclosures [Line Items]
Changes in instrument-specific credit risk - Total	$ 223	$ 254	$ 155	$ 152
Other changes in fair value	(96)	(60)	(107)	97
Fair value gains (losses), net	127	194	48	249
Loans [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Changes in instrument-specific credit risk - Loans	73	67	110	92
Other changes in fair value	(15)	(33)	(65)	461
Fair value gains (losses), net	58	34	45	553
Long-term debt [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Changes in instrument-specific credit risk - Long-Term Debt	150	187	45	60
Other changes in fair value	(81)	(27)	(42)	(364)
Fair value gains (losses), net	$ 69	$ 160	$ 3	$ (304)