Federal National Mortgage Association (FNMA) 10-K 19 Feb 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2015	Jan. 31, 2016	Jun. 30, 2015
Entity Information [Line Items]
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-K
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		1,158,082,750
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 2.7

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2015	Dec. 31, 2014
ASSETS
Cash and cash equivalents	$ 14,674,000,000	$ 22,023,000,000
Restricted cash (includes $25,865 and $27,515, respectively, related to consolidated trusts)	30,879,000,000	32,542,000,000
Federal funds sold and securities purchased under agreements to resell or similar arrangements	27,350,000,000	30,950,000,000
Investments in securities:
Trading, at fair value	39,908,000,000	31,504,000,000
Available-for-sale, at fair value (includes $285 and $596, respectively, related to consolidated trusts)	20,230,000,000	30,654,000,000
Total investments in securities	60,138,000,000	62,158,000,000
Mortgage loans:
Loans held for sale, at lower of cost or fair value	5,361,000,000	331,000,000
Loans held for investment, at amortized cost	3,042,234,000,000	3,054,704,000,000
Allowance for loan losses	(27,951,000,000)	(35,541,000,000)
Total loans held for investment, net of allowance	3,014,283,000,000	3,019,163,000,000
Total mortgage loans	3,019,644,000,000	3,019,494,000,000
Deferred tax assets, net	37,187,000,000	42,206,000,000
Accrued interest receivable, net (includes $6,974 and $7,169, respectively, related to consolidated trusts)	7,726,000,000	8,193,000,000
Acquired property, net	6,766,000,000	10,618,000,000
Other assets	17,553,000,000	19,992,000,000
Total assets	3,221,917,000,000	3,248,176,000,000
Liabilities:
Accrued interest payable (includes $8,194 and $8,282, respectively, related to consolidated trusts)	9,794,000,000	10,232,000,000
Other liabilities (includes $448 and $503, respectively, related to consolidated trusts)	10,393,000,000	12,069,000,000
Total liabilities	3,217,858,000,000	3,244,456,000,000
Commitments and contingencies (Note 18)	0	0
Fannie Mae stockholders’ equity:
Senior preferred stock, 1,000,000 shares issued and outstanding	117,149,000,000	117,149,000,000
Preferred stock, 700,000,000 shares are authorized— 555,374,922 shares issued and outstanding	19,130,000,000	19,130,000,000
Common stock, no par value, no maximum authorization—1,308,762,703 shares issued and 1,158,082,750 shares outstanding	687,000,000	687,000,000
Accumulated deficit	(126,942,000,000)	(127,618,000,000)
Accumulated other comprehensive income	1,407,000,000	1,733,000,000
Treasury stock, at cost, 150,679,953 shares	(7,401,000,000)	(7,401,000,000)
Total Fannie Mae stockholders’ equity	4,030,000,000	3,680,000,000
Noncontrolling interest	29,000,000	40,000,000
Total equity (See Note 1: Senior Preferred Stock and Warrant Issued to Treasury and Earnings (Loss) per Share for information on our dividend obligation to Treasury)	4,059,000,000	3,720,000,000
Total liabilities and equity	3,221,917,000,000	3,248,176,000,000
Fannie Mae [Member]
Mortgage loans:
Loans held for investment, at amortized cost	233,054,000,000	272,360,000,000
Allowance for loan losses	(26,510,000,000)	(33,117,000,000)
Total mortgage loans	211,887,000,000	239,549,000,000
Liabilities:
Debt (includes $11,133 and $6,403, respectively, of debt of Fannie Mae and $23,609 and $19,483, respectively, of debt of consolidated trusts, at fair value)	386,135,000,000	460,443,000,000
Consolidated Trusts [Member]
ASSETS
Restricted cash (includes $25,865 and $27,515, respectively, related to consolidated trusts)	25,865,000,000	27,515,000,000
Investments in securities:
Available-for-sale, at fair value (includes $285 and $596, respectively, related to consolidated trusts)	285,000,000	596,000,000
Mortgage loans:
Loans held for investment, at amortized cost	2,809,180,000,000	2,782,344,000,000
Allowance for loan losses	(1,441,000,000)	(2,424,000,000)
Total mortgage loans	2,807,757,000,000	2,779,945,000,000
Accrued interest receivable, net (includes $6,974 and $7,169, respectively, related to consolidated trusts)	6,974,000,000	7,169,000,000
Total assets	2,850,000,000,000	2,830,000,000,000
Liabilities:
Accrued interest payable (includes $8,194 and $8,282, respectively, related to consolidated trusts)	8,194,000,000	8,282,000,000
Debt (includes $11,133 and $6,403, respectively, of debt of Fannie Mae and $23,609 and $19,483, respectively, of debt of consolidated trusts, at fair value)	2,811,536,000,000	2,761,712,000,000
Other liabilities (includes $448 and $503, respectively, related to consolidated trusts)	$ 448,000,000	$ 503,000,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
ASSETS
Restricted cash (includes $25,865 and $27,515, respectively, related to consolidated trusts)	$ 30,879	$ 32,542
Investments in securities:
Available-for-sale, at fair value (includes $285 and $596, respectively, related to consolidated trusts)	20,230	30,654
Mortgage loans:
Loans held for investment, at amortized cost of consolidated trusts (includes $14,075 and $15,629, respectively, at fair value)	14,075	15,629
Accrued interest receivable, net (includes $6,974 and $7,169, respectively, related to consolidated trusts)	7,726	8,193
Liabilities:
Accrued interest payable (includes $8,194 and $8,282, respectively, related to consolidated trusts)	9,794	10,232
Other liabilities (includes $448 and $503, respectively, related to consolidated trusts)	$ 10,393	$ 12,069
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, no par value, no maximum authorization--1,308,762,703 shares issued	1,308,762,703	1,308,762,703
Common stock, no par value, no maximum authorization--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 $25,865 and $27,515, respectively, related to consolidated trusts)	$ 25,865	$ 27,515
Investments in securities:
Available-for-sale, at fair value (includes $285 and $596, respectively, related to consolidated trusts)	285	596
Mortgage loans:
Accrued interest receivable, net (includes $6,974 and $7,169, respectively, related to consolidated trusts)	6,974	7,169
Liabilities:
Accrued interest payable (includes $8,194 and $8,282, respectively, related to consolidated trusts)	8,194	8,282
Debt at fair value	23,609	19,483
Other liabilities (includes $448 and $503, respectively, related to consolidated trusts)	448	503
Fannie Mae [Member]
Liabilities:
Debt at fair value	$ 11,133	$ 6,403

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Interest income:
Trading securities	$ 444	$ 553	$ 779
Available-for-sale securities	1,156	1,622	2,357
Mortgage loans (includes $97,971, $101,835 and $101,448, respectively, related to consolidated trusts)	107,699	112,120	114,238
Other	143	110	175
Total interest income	109,442	114,405	117,549
Interest expense:
Short-term debt	146	94	131
Long-term debt (includes $80,326, $85,835 and $84,751, respectively, related to consolidated trusts)	87,887	94,343	95,014
Total interest expense	88,033	94,437	95,145
Net interest income	21,409	19,968	22,404
Benefit for credit losses	795	3,964	8,949
Net interest income after benefit for credit losses	22,204	23,932	31,353
Non-interest Income (loss)
Investment gains, net	1,336	936	1,127
Fair value gains (losses), net	(1,767)	(4,833)	2,959
Fee and other income	1,348	5,887	3,930
Non-interest income	917	1,990	8,016
Administrative expenses:
Salaries and employee benefits	1,319	1,321	1,218
Professional services	984	1,076	910
Occupancy expenses	182	203	189
Other administrative expenses	565	177	228
Total administrative expenses	3,050	2,777	2,545
Foreclosed property expense (income)	1,629	142	(2,839)
Temporary Payroll Cut Continuation Act of 2011 (TCCA) fees	1,621	1,375	1,001
Other expenses, net	613	478	95
Total expenses	6,913	4,772	802
Income before federal income taxes	16,208	21,150	38,567
Benefit (provision) for federal income taxes	(5,253)	(6,941)	45,415
Net income	10,955	14,209	83,982
Other comprehensive income (loss):
Changes in unrealized gains on available-for-sale securities, net of reclassification adjustments and taxes	(763)	494	693
Other	437	36	126
Total other comprehensive income (loss)	(326)	530	819
Total comprehensive income	10,629	14,739	84,801
Less: Comprehensive income attributable to noncontrolling interest	(1)	(1)	(19)
Total comprehensive income attributable to Fannie Mae	10,628	14,738	84,782
Less: Net income attributable to noncontrolling interest	(1)	(1)	(19)
Net income attributable to Fannie Mae	10,954	14,208	83,963
Dividends distributed or available for distribution to senior preferred stockholder (Note 11)	(11,216)	(15,323)	(85,419)
Net loss attributable to common stockholders (Note 11)	$ (262)	$ (1,115)	$ (1,456)
Loss per share: Basic and Diluted (in dollars per share)	$ (0.05)	$ (0.19)	$ (0.25)
Weighted-average common shares outstanding: Basic and Diluted	5,762	5,762	5,762

Consolidated Statements of Ope5

Consolidated Statements of Operations and Comprehensive Loss (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Mortgage loans interest income	$ 107,699	$ 112,120	$ 114,238
Long-term debt interest expense	87,887	94,343	95,014
Consolidated Trusts [Member]
Mortgage loans interest income	97,971	101,835	101,448
Long-term debt interest expense	$ 80,326	$ 85,835	$ 84,751

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows provided by (used in) operating activities:
Net income	$ 10,955	$ 14,209	$ 83,982
Reconciliation of net income to net cash provided by (used in) operating activities:
Amortization of cost basis adjustments	(6,298)	(4,265)	(5,104)
Benefit for credit losses	(795)	(3,964)	(8,949)
Valuation gains	(510)	(2,159)	(2)
Current and deferred federal income taxes	4,083	4,126	(47,766)
Net change in trading securities	(10,153)	(2,666)	1,575
Net gains related to the disposition of acquired property and preforeclosure sales, including credit enhancements	(3,055)	(4,510)	(6,024)
Other, net	(900)	(2,109)	(4,809)
Net cash provided by (used in) operating activities	(6,673)	(1,338)	12,903
Cash flows provided by investing activities:
Purchases of trading securities held for investment	0	0	(7,521)
Proceeds from maturities and paydowns of trading securities held for investment	768	1,358	2,491
Proceeds from sales of trading securities held for investment	1,104	1,668	14,585
Proceeds from maturities and paydowns of available-for-sale securities	4,394	5,853	10,116
Proceeds from sales of available-for-sale securities	8,249	3,265	15,497
Purchases of loans held for investment	(187,194)	(132,650)	(195,386)
Net change in restricted cash	1,663	(3,547)	38,924
Advances to lenders	(118,746)	(100,045)	(139,162)
Proceeds from disposition of acquired property and preforeclosure sales	20,757	25,476	38,349
Net change in federal funds sold and securities purchased under agreements to resell or similar arrangements	3,600	8,025	(6,475)
Other, net	527	197	1,373
Net cash provided by investing activities	248,324	224,667	452,754
Cash flows used in financing activities:
Payments of cash dividends on senior preferred stock to Treasury	(10,278)	(20,594)	(82,452)
Other, net	26	70	(145)
Net cash used in financing activities	(249,000)	(220,534)	(467,546)
Net increase (decrease) in cash and cash equivalents	(7,349)	2,795	(1,889)
Cash and cash equivalents at beginning of period	22,023	19,228	21,117
Cash and cash equivalents at end of period	14,674	22,023	19,228
Cash paid during the period for:
Interest	104,928	108,667	109,240
Income taxes	1,170	2,815	2,350
Non-cash activities:
Net mortgage loans acquired by assuming debt	220,168	190,151	433,007
Net transfers from mortgage loans of Fannie Mae to mortgage loans of consolidated trusts	175,104	113,611	179,097
Transfers from advances to lenders to loans held for investment of consolidated trusts	114,851	93,909	137,074
Net transfers from mortgage loans to acquired property	17,534	24,742	34,024
Transfers of mortgage loans from held for investment to held for sale	8,601	2,194	1,341
Fannie Mae [Member]
Cash flows provided by investing activities:
Proceeds from repayments of loans acquired as held for investment	25,776	24,840	47,628
Proceeds from sales of loans acquired as held for investment	3,196	1,879	1,247
Cash flows used in financing activities:
Proceeds from the issuance of debt	443,371	380,282	372,361
Payments to redeem debt	(518,575)	(450,140)	(459,745)
Consolidated Trusts [Member]
Cash flows provided by investing activities:
Proceeds from repayments of loans acquired as held for investment	484,230	388,348	631,088
Cash flows used in financing activities:
Proceeds from the issuance of debt	347,614	275,353	409,979
Payments to redeem debt	$ (511,158)	$ (405,505)	$ (707,544)

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity - USD ($) shares in Millions, $ in Millions	Total	Senior Preferred Stock	Preferred Stock	Common Stock	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Noncontrolling Interest
Balance (shares) at Dec. 31, 2012		1	556	1,158
Balance at Dec. 31, 2012	$ 7,224	$ 117,149	$ 19,130	$ 687	$ (122,766)	$ 384	$ (7,401)	$ 41
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Change in investment in noncontrolling interest	(10)							(10)
Comprehensive income:
Net income	83,982				83,963			19
Other comprehensive income, net of tax effect:
Changes in net unrealized gains on available-for-sale securities (net of tax of $529, $389 and $151, respectively)	983					983
Reclassification adjustment for gains included in net income (net of tax of $157, $123 and $253, respectively)	(290)					(290)
Prior service cost and actuarial gains, net of amortization for defined benefit plans (net of tax of $68, $20 and $0, respectively)	126					126
Total comprehensive income	84,801
Senior preferred stock dividends	(82,452)				(82,452)
Other	28				28
Balance at Dec. 31, 2013	9,591	$ 117,149	$ 19,130	$ 687	(121,227)	1,203	(7,401)	50
Balance (shares) at Dec. 31, 2013		1	556	1,158
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Change in investment in noncontrolling interest	(11)							(11)
Comprehensive income:
Net income	14,209				14,208			1
Other comprehensive income, net of tax effect:
Changes in net unrealized gains on available-for-sale securities (net of tax of $529, $389 and $151, respectively)	722					722
Reclassification adjustment for gains included in net income (net of tax of $157, $123 and $253, respectively)	(228)					(228)
Prior service cost and actuarial gains, net of amortization for defined benefit plans (net of tax of $68, $20 and $0, respectively)	36					36
Total comprehensive income	14,739
Senior preferred stock dividends	(20,594)				(20,594)
Other	(5)				(5)
Balance at Dec. 31, 2014	3,720	$ 117,149	$ 19,130	$ 687	(127,618)	1,733	(7,401)	40
Balance (shares) at Dec. 31, 2014		1	556	1,158
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Change in investment in noncontrolling interest	(12)							(12)
Comprehensive income:
Net income	10,955				10,954			1
Other comprehensive income, net of tax effect:
Changes in net unrealized gains on available-for-sale securities (net of tax of $529, $389 and $151, respectively)	(280)					(280)
Reclassification adjustment for gains included in net income (net of tax of $157, $123 and $253, respectively)	(483)					(483)
Prior service cost and actuarial gains, net of amortization for defined benefit plans (net of tax of $68, $20 and $0, respectively)	437					437
Total comprehensive income	10,629
Senior preferred stock dividends	(10,278)				(10,278)
Balance at Dec. 31, 2015	4,059	$ 117,149	$ 19,130	$ 687	(126,942)	1,407	(7,401)	29
Balance (shares) at Dec. 31, 2015		1	556	1,158
Balance at Sep. 30, 2015	4,000
Comprehensive income:
Net income	2,467
Balance at Dec. 31, 2015	$ 4,059	$ 117,149	$ 19,130	$ 687	$ (126,942)	$ 1,407	$ (7,401)	$ 29
Balance (shares) at Dec. 31, 2015		1	556	1,158

Consolidated Statements of Cha8

Consolidated Statements of Changes in Equity (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Stockholders' Equity [Abstract]
Changes in net unrealized gains on available-for-sale securities, net of tax	$ 151	$ 389	$ 529
Reclassification adjustment for gains included in net income, net of tax	253	123	157
Prior service cost and actuarial gains, net of amortization for defined benefit plans, net of tax	$ 0	$ 20	$ 68

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 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. We operate in the secondary mortgage market by purchasing mortgage loans and mortgage-related securities, including mortgage-related securities guaranteed by us, from primary mortgage market institutions, such as commercial banks, savings and loan associations, mortgage banking companies, securities dealers and other investors. We do not lend money directly to consumers in the primary mortgage market. We provide additional liquidity in the secondary mortgage market by issuing guaranteed mortgage-related securities. We operate under three business segments: Single-Family Credit Guaranty (“Single-Family”), Multifamily and Capital Markets. Our Single-Family segment generates revenue primarily from the guaranty fees on the mortgage loans underlying guaranteed single-family Fannie Mae mortgage-backed securities (“Fannie Mae MBS”). Our Multifamily segment generates revenue from a variety of sources, including guaranty fees on the mortgage loans underlying multifamily Fannie Mae MBS, transaction fees associated with the multifamily business and bond credit enhancement fees. Our Capital Markets segment invests in mortgage loans, mortgage-related securities and other investments, and generates income primarily from the difference, or spread, between the yield on the mortgage assets we own and the interest we pay on the debt we issue in the global capital markets to fund the purchases of these mortgage assets. 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. We were directed by FHFA to voluntarily delist our common stock and each listed series of our preferred stock from the New York Stock Exchange and the Chicago Stock Exchange. The last trading day for the listed securities on the New York Stock Exchange and the Chicago Stock Exchange was July 7, 2010, and since July 8, 2010, the securities have been traded on the over-the-counter market. The conservator has the power to transfer or sell any asset or liability of Fannie Mae (subject to limitations and post-transfer notice provisions for transfers of qualified financial contracts) without any approval, assignment of rights or consent of any party. The GSE Act, however, provides that mortgage loans and mortgage-related assets that have been transferred to a Fannie Mae MBS trust must be held by the conservator for the beneficial owners of the Fannie Mae MBS and cannot be used to satisfy the general creditors of Fannie Mae. Neither the conservatorship nor the terms of our agreements with Treasury change our obligation to make required payments on our debt securities or perform under our mortgage guaranty obligations. FHFA issued a rule establishing a framework for conservatorship and receivership operations for the GSEs, which became effective in 2011. The rule established procedures for conservatorship and receivership, and priorities of claims for contract parties and other claimants. This rule is part of FHFA’s implementation of the powers provided by the GSE Act. The conservatorship has no specified termination date and there continues to be significant uncertainty regarding our future, including how long we will continue to exist in our current form, the extent of our role in the market, how long we will be in conservatorship, what form we will have and what ownership interest, if any, our current common and preferred stockholders will hold in us after the conservatorship is terminated and whether we will continue to exist following conservatorship. Under the GSE Act, FHFA must place us into receivership if the Director of FHFA makes a written determination that our assets are less than our obligations or if we have not been paying our debts, in either case, for a period of 60 days . In addition, the Director of FHFA may place us into receivership at his discretion at any time for other reasons set forth in the GSE Act, including if we are critically undercapitalized or if we are undercapitalized and have no reasonable prospect of becoming adequately capitalized. Should we be placed into receivership, different assumptions would be required to determine the carrying value of our assets, which could lead to substantially different financial results. We are not aware of any plans of FHFA to fundamentally change our business model or capital structure in the near term. Senior Preferred Stock and Warrant Issued to Treasury Senior Preferred Stock On September 7, 2008, we, through FHFA in its capacity as conservator, entered into a senior preferred stock purchase agreement with Treasury. This agreement was amended and restated on September 26, 2008. The amended and restated agreement was subsequently amended on May 6, 2009, December 24, 2009 and August 17, 2012. Pursuant to the senior preferred stock purchase agreement, Treasury has committed to provide us with funding as described below to help us maintain a positive net worth thereby avoiding the mandatory receivership trigger described above. As consideration for Treasury’s funding commitment, we issued one million shares of senior preferred stock and a warrant to purchase shares of our common stock to Treasury. As of December 31, 2015 and 2014 , we have received a total of $ 116.1 billion from Treasury pursuant to the senior preferred stock purchase agreement. 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 December 31, 2015 . As of December 31, 2015 , the amount of remaining funding available to us under the senior preferred stock purchase agreement was $117.6 billion . In August 2012, we, through FHFA acting on our behalf in its capacity as conservator, entered into an amendment to the senior preferred stock purchase agreement with Treasury. The amendment included, among other things, the following revisions: • Dividends. The method for calculating the amount of dividends we are required to pay Treasury on the senior preferred stock changed as of January 1, 2013. Effective January 1, 2013, when, as and if declared, the amount of dividends payable on the senior preferred stock for a dividend period is determined based on our net worth as of the end of the immediately preceding fiscal quarter. Our net worth as defined by the agreement is the amount, if any, by which our total assets (excluding Treasury’s funding commitment and any unfunded amounts related to the commitment) exceed our total liabilities (excluding any obligation in respect of capital stock), in each case as reflected on our balance sheet prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). For each dividend period from January 1, 2013 through and including December 31, 2017, the dividend amount will be the amount, if any, by which our net worth as of the end of the immediately preceding fiscal quarter exceeds an applicable capital reserve amount. If our net worth does not exceed the applicable capital reserve amount as of the end of a fiscal quarter, then no dividend amount will accrue or be payable for the applicable dividend period. The capital reserve amount was $2.4 billion and $1.8 billion for dividend periods in 2014 and 2015 , respectively, decreased to $1.2 billion for dividend periods in 2016 , and will continue to be reduced by $600 million each year until it reaches zero on January 1, 2018. For each dividend period thereafter, the dividend amount will be the entire amount of our net worth, if any, as of the end of the immediately preceding fiscal quarter. • Periodic Commitment Fee. Effective January 1, 2013, the periodic commitment fee provided for under the agreement will not be set, accrue or be payable, as long as the dividend payment provisions described above remain in effect. This amendment to the senior preferred stock purchase agreement was not accounted for as an extinguishment of the existing senior preferred stock purchase agreement. As a result, we did not recognize a gain or loss upon modification of the senior preferred stock purchase agreement. Consistent with our accounting policy, dividends on the senior preferred stock are accrued upon declaration, which occurs each quarter when FHFA directs us to pay the quarterly dividend to Treasury. On December 31, 2015 , we paid Treasury a dividend of $2.2 billion based on our net worth of $4.0 billion as of September 30, 2015 , less the applicable capital reserve of $1.8 billion . Based on the terms of the senior preferred stock, we expect to pay Treasury a dividend of $2.9 billion by March 31, 2016 based on our net worth of $4.1 billion as of December 31, 2015 , less the applicable capital reserve of $1.2 billion . Warrant Issued to Treasury On September 7, 2008, we issued a warrant to Treasury giving it the right to purchase, at a nominal price, shares of our common stock equal to 79.9% of the total common stock outstanding on a fully diluted basis on the date Treasury exercises the warrant. Treasury has the right to exercise the warrant, in whole or in part, at any time on or before September 7, 2028. We recorded the warrant at fair value in our stockholders’ equity as a component of additional paid-in-capital. The fair value of the warrant was calculated using the Black-Scholes Option Pricing Model. Since the warrant has an exercise price of $0.00001 per share, the model is insensitive to the risk-free rate and volatility assumptions used in the calculation and the share value of the warrant is equal to the price of the underlying common stock. We estimated that the fair value of the warrant at issuance was $3.5 billion based on the price of our common stock on September 8, 2008, which was after the dilutive effect of the warrant had been reflected in the market price. Subsequent changes in the fair value of the warrant are not recognized in our financial statements. If the warrant is exercised, the stated value of the common stock issued will be reclassified as “Common stock” in our consolidated balance sheets. Because the warrant’s exercise price per share is considered non-substantive (compared to the market price of our common stock), the warrant was determined to have characteristics of non-voting common stock, and thus is included in the computation of basic and diluted loss per share. The weighted-average shares of common stock outstanding for 2015 , 2014 and 2013 included shares of common stock that would be issuable upon full exercise of the warrant issued to Treasury. Impact of U.S. Government Support We continue to rely on support from Treasury to eliminate any net worth deficits we may experience in the future, which would otherwise trigger our being placed into receivership. Based on consideration of all the relevant conditions and events affecting our operations, including our reliance on the U.S. government, we continue to operate as a going concern and in accordance with our delegation of authority from FHFA. We fund our business primarily through the issuance of short-term and long-term debt securities in the domestic and international capital markets. Because debt issuance is our primary funding source, we are subject to “roll-over,” or refinancing, risk on our outstanding debt. Our ability to issue long-term debt has been strong primarily due to actions taken by the federal government to support us. We believe that continued federal government support of our business, as well as our status as a GSE, are essential to maintaining our access to debt funding. Changes or perceived changes in federal government support of our business or our status as a GSE could materially and adversely affect our liquidity, financial condition and results of operations. In addition, due to our reliance on the U.S. government’s support, our access to debt funding or the cost of debt funding also could be materially adversely affected by a change or perceived change in the creditworthiness of the U.S. government. A downgrade in our credit ratings could reduce demand for our debt securities and increase our borrowing costs. Future changes or disruptions in the financial markets could significantly change the amount, mix and cost of funds we obtain, which also could increase our liquidity and roll-over risk and have a material adverse impact on our liquidity, financial condition and results of operations. In 2011, the Administration released a report to Congress on ending the conservatorships of the GSEs and reforming America’s housing finance market. The report provides that the Administration will work with FHFA to determine the best way to responsibly reduce Fannie Mae and Freddie Mac’s role in the market and ultimately wind down both institutions. The report emphasizes the importance of proceeding with a careful transition plan and providing the necessary financial support to Fannie Mae and Freddie Mac during the transition period. In 2013, the White House released a paper confirming that a core principle of the Administration’s housing policy priorities is to wind down Fannie Mae and Freddie Mac through a responsible transition. In 2015, the White House reaffirmed the Administration’s view that housing finance reform should include ending Fannie Mae and Freddie Mac’s business model. Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with GAAP. To conform to our current period presentation, we have reclassified certain amounts reported in our prior periods’ consolidated financial statements. 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 is 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 is 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 benefit for credit losses and did not retrospectively adjust our 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 is 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 redesignation 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 aligns the unit of account that is used for both the initial and subsequent lower of cost or fair value measurements on our HFS portfolio. Additionally, by performing the lower of cost or fair value calculation at the loan level, the adjustment is calculated on a more disaggregated basis. As this change in accounting policy was 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 our consolidated financial statements for this change. 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 December 31, 2015 , Treasury held an investment in our senior preferred stock with an aggregate liquidation preference of $117.1 billion . FHFA’s control of both us and Freddie Mac has caused us, FHFA and Freddie Mac to be deemed related parties. In October 2013, Fannie Mae and Freddie Mac established Common Securitization Solutions, LLC (“CSS”), a jointly owned limited liability company to operate a common securitization platform; therefore, CSS is also deemed a related party. Transactions with Treasury Our administrative expenses were reduced by $68 million , $71 million and $92 million for the years ended December 31, 2015 , 2014 and 2013 , 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 years ended December 31, 2015 , 2014 and 2013 , we made tax payments of $1.2 billion , $2.8 billion and $2.4 billion , respectively, to the Internal Revenue Service (“IRS”), a bureau of Treasury. We received a refund of $277 million from the IRS during the year ended December 31, 2015 for income tax adjustments related to tax years 2004 through 2010. In 2009, we entered into a memorandum of understanding with Treasury, FHFA and Freddie Mac pursuant to which we agreed to provide assistance to state and local housing finance agencies (“HFAs”) through two primary programs: a temporary credit and liquidity facilities (“TCLF”) program and a new issue bond (“NIB”) program. Treasury bears 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 also bears any losses of unpaid interest under the two programs. Pursuant to the TCLF program, Treasury purchased participation interests in temporary credit and liquidity facilities provided by us and Freddie Mac which created a credit and liquidity backstop for the HFAs. We had no amount outstanding under the TCLF program as of December 31, 2015 , which ended as scheduled in July 2015, and therefore no potential risk of loss under the TCLF program. We had $390 million outstanding under the TCLF program, which includes principal and interest, of standby credit and liquidity support as of December 31, 2014 . Pursuant to the NIB program, Treasury purchased new securities issued and guaranteed by us and Freddie Mac, which are backed by new housing bonds issued by the HFAs. We had $3.7 billion and $4.2 billion outstanding of pass-through securities backed by single-family and multifamily housing bonds issued by HFAs as of December 31, 2015 and 2014 , respectively. As of December 31, 2015 , there had been no losses of principal or interest under the NIB program. In December 2011, Congress enacted the Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) which, among other provisions, requires that we increase our single-family guaranty fees by at least 10 basis points and remit this increase to Treasury. Effective April 1, 2012, the guaranty fee on all single-family residential mortgages delivered to Fannie Mae on or after that date was increased by 10 basis points. FHFA and Treasury have advised us to remit this fee increase to Treasury with respect to all loans acquired by us on or after April 1, 2012 and before January 1, 2022, and to continue to remit these amounts to Treasury on and after January 1, 2022 with respect to loans we acquired before this date until those loans are paid off or otherwise liquidated. The resulting fee revenue and expense are recorded in “Mortgage loans interest income” and “TCCA fees,” respectively, in our consolidated statements of operations and comprehensive income. We recognized $1.6 billion , $ 1.4 billion and $1.0 billion as TCCA fees for the years ended December 31, 2015 , 2014 and 2013 , respectively. We remitted $1.6 billion , $ 1.3 billion and $829 million in TCCA-related guaranty fees to Treasury for our quarterly obligations during the years ended December 31, 2015 , 2014 and 2013 , respectively. For the three months ended December 31, 2015 , we have incurred $429 million in TCCA-related guaranty fees that have not been remitted to Treasury. For the year ended December 31, 2015 , we incurred expenses in connection with certain funding obligations under the GSE Act, a portion of which is attributable to Treasury’s Capital Magnet and HOPE Funds. These expenses, recognized in “Other expenses, net” in our consolidated statements of operations and comprehensive income, were measured as the product of 4.2 basis points and the unpaid principal balance of our total new business purchases for the year ended December 31, 2015 . Pursuant to the GSE Act and directions from FHFA, on or before February 29, 2016, we expect to make payments of $57 million to the Treasury Capital Magnet Fund and $54 million to the Treasury HOPE Fund. In addition to the transactions with Treasury mentioned above, we also purchase and sell Treasury securities in the normal course of business. As of December 31, 2015 and 2014 , we held Treasury securities with a fair value of $29.5 billion and $19.5 billion , respectively, and accrued interest receivable of $15 million and $16 million , respectively. We recognized interest income on these securities held by us of $35 million , $18 million and $28 million for the years ended December 31, 2015 , 2014 and 2013 , respectively. Transactions with Freddie Mac As of December 31, 2015 and 2014 , we held Freddie Mac mortgage-related securities with a fair value of $5.6 billion and $6.9 billion , respectively, and accrued interest receivable of $22 million and $26 million , respectively. We recognized interest income on these securities held by us of $226 million , $283 million and $387 million for the years ended December 31, 2015 , 2014 and 2013 , respectively. In addition, Freddie Mac may be an investor in variable interest entities (“VIEs”) that we have consolidated, and we may be an investor in VIEs that Freddie Mac has consolidated. Transactions with FHFA The GSE Act authorizes FHFA to establish an annual assessment for regulated entities, including Fannie Mae, which is payable on a semi-annual basis (April and October), for FHFA’s costs and expenses, as well as to maintain FHFA’s working capital. We recognized FHFA assessment fees, which are recorded in “Administrative expenses” in our consolidated statements of operations and comprehensive income, of $112 million , $108 million and $109 million for the years ended December 31, 2015 , 2014 and 2013 , respectively. Transactions with CSS In connection with our jointly owned company with Freddie Mac, for the years ended December 31, 2015 and 2014 , we contributed $66 million and $43 million of capital into CSS, respectively. No other transactions outside of normal business activities have occurred between us and Freddie Mac during the years ended December 31, 2015 , 2014 or 2013 . Use of Estimates Preparing 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 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 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 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. In 2014, we updated the assumptions used to estimate cash flows for individually impaired single-family loans within our allowance for loan losses. This update resulted in a decrease to our allowance for loan losses and an incremental benefit for credit losses of approximately $600 million . In 2013, we updated the assumptions and data used to estimate our allowance for loan losses for individually impaired single-family loans based on current observable performance trends as well as future expectations of payment behavior. This update resulted in a decrease to our allowance for loan losses and an incremental benefit for credit losses of approximately $2.2 billion . In 2013, we concluded that it was more likely than not that our deferred tax assets, except the deferred tax assets relating to capital loss carryforwards, would be realized. This conclusion was based upon significant positive evidence of our ability to generate sufficient taxable income and utilize our net operating loss carryforwards. As a result, we released the valuation allowance on our deferred tax assets as of March 31, 2013, except for amounts that were expected to be released against income before federal income taxes for the remainder of the year. The release of the valuation allowance resulted in the recognition of $58.3 billion in benefit for income taxes in our consolidated statements of operations and comprehensive income in 2013. Principles of Consolidation Our consolidated financial statements include our accounts as well as the accounts of the other entities in which we have a controlling financial interest. All intercompany balances and transactions have been eliminated. The typical condition for a controlling financial interest is ownership of a majority of the voting interests of an entity. A controlling financial interest may also exist in entities through arrangements that do not involve voting interests, such as a VIE. VIE Assessment We have interests in various entities that are considered VIEs. A VIE is an entity (1) that has total equity at risk that is not sufficient to finance its activities without additional subordinated financial support from other entities, (2) where the group of equity holders does not have the power to direct the activities of the entity that most significantly impact the entity’s economic performance, or the obligation to absorb the entity’s expected losses or the right to receive the entity’s expected residual returns, or both, or (3) where the voting rights of some investors are not proportional to their obligations to absorb the expected losses of the entity, their rights to receive the expected residual returns of the entity, or both, and substantially all of the entity’s activities either involve or are conducted on behalf of an investor that has disproportionately few voting rights. We determine if an entity is a VIE by performing a qualitative analysis, which requires certain subjective decisions including, but not limited to, the design of the entity, the variability that the entity was designed to create and pass along to its interest holders, the rights of the parties and the purpose of the arrangement. If we cannot conclude after a qualitative analysis whether an entity is a VIE, we perform a quantitative analysis. The primary types of VIE entities with which we are involved are securitization trusts guaranteed by us via lender swap and portfolio securitization transactions, limited partnership investments in low-income housing tax credit (“LIHTC”) and other housing partnerships, as well as mortgage and asset-backed trusts that were not created by us. Primary Beneficiary Determination If an entity is a VIE, we consider whether our variable interest in that entity causes us to be the primary beneficiary. We are deemed to be the primary beneficiary of a VIE when we have both (1) the power to direct the activities of the VIE that most significantly impact the entity’s economic performance, and (2) exposure to benefits and/or losses that could potentially be significant to the entity. The primary beneficiary of the VIE is required to consolidate and account for the assets, liabilities, and noncontrolling interests of the VIE in its consolidated financial statements. The assessment of which party has the power to direct the activities of the VIE may require significant management judgment when (1) more than one party has power or (2) more than one party is involved in the design of the VIE but no party has the power to

Consolidations and Transfers of

Consolidations and Transfers of Financial Assets	12 Months Ended
	Dec. 31, 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 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. Types of VIEs Securitization Trusts Under our lender swap and portfolio securitization transactions, mortgage loans are transferred to a trust specifically for the purpose of issuing a single class of guaranteed securities that are collateralized by the underlying mortgage loans. The trust’s permitted activities include receiving the transferred assets, issuing beneficial interests, establishing the guaranty and servicing the underlying mortgage loans. In our capacity as issuer, master servicer, trustee and guarantor, we earn fees for our obligations to each trust. Additionally, we may retain or purchase a portion of the securities issued by each trust. We have securitized mortgage loans since 1981. In our structured securitization transactions, we earn fees for assisting lenders and dealers with the design and issuance of structured mortgage-related securities. The trusts created in these transactions have permitted activities that are similar to those for our lender swap and portfolio securitization transactions. The assets of these trusts may include mortgage-related securities and/or mortgage loans. The trusts created for Fannie Megas issue single-class securities while the trusts created for REMIC, grantor trust and stripped mortgage-backed securities (“SMBS”) issue single-class and multi-class securities, the latter of which separate the cash flows from underlying assets into separately tradable interests. Our obligations and continued involvement in these trusts are similar to those described for lender swap and portfolio securitization transactions. We have securitized mortgage assets in structured transactions since 1986. We also invest in mortgage-backed securities that have been issued via private-label trusts. These trusts are structured to provide investors with a beneficial interest in a pool of receivables or other financial assets, typically mortgage loans. The trusts act as vehicles to allow loan originators to securitize assets. Securities are structured from the underlying pool of assets to provide for varying degrees of risk. The originators of the financial assets or the underwriters of the transaction create the trusts and typically own the residual interest in the trusts’ assets. Our involvement in these entities is typically limited to our recorded investment in the beneficial interests that we have purchased. We have invested in these vehicles since 1987. Limited Partnerships We have historically made equity investments in various limited partnerships that sponsor affordable housing projects utilizing the low-income housing tax credit pursuant to Section 42 of the Internal Revenue Code. The purpose of these investments is to increase the supply of affordable housing in the United States and to serve communities in need. In addition, our investments in LIHTC partnerships generate both tax credits and net operating losses that may reduce our federal income tax liability. Our LIHTC investments primarily represent limited partnership interests in entities that have been organized by a fund manager who acts as the general partner. These fund investments seek out equity investments in LIHTC operating partnerships that have been established to identify, develop and operate multifamily housing that is leased to qualifying residential tenants. We no longer recognize net operating losses or impairment on our LIHTC partnership investments as the carrying value is zero . We did not make any LIHTC investments in 2015 , 2014 or 2013 , other than pursuant to existing prior commitments. Consolidated VIEs If an entity is a VIE, we consider whether our variable interest in that entity causes us to be the primary beneficiary. The primary beneficiary of the VIE is required to consolidate and account for the assets, liabilities and noncontrolling interests of the VIE in its consolidated financial statements. An enterprise is deemed to be the primary beneficiary when the enterprise has the power to direct the activities of the VIE that most significantly impact the entity’s economic performance and exposure to benefits and/or losses could potentially be significant to the entity. In general, the investors in the obligations of consolidated VIEs have recourse only to the assets of those VIEs and do not have recourse to us, except where we provide a guaranty to the VIE. 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 of December 31, 2015 2014 (Dollars in millions) Assets and liabilities recorded in our consolidated balance sheets related to mortgage-backed trusts: Assets: Trading securities: Fannie Mae securities $ 4,704 $ 4,790 Non-Fannie Mae securities 5,596 7,073 Total trading securities 10,300 11,863 Available-for-sale securities: Fannie Mae securities 3,936 5,043 Non-Fannie Mae securities 14,644 22,776 Total available-for-sale securities 18,580 27,819 Other assets 100 111 Other liabilities (827 ) (1,440 ) Net carrying amount $ 28,153 $ 38,353 Our maximum exposure to loss generally represents the greater of our recorded investment in the entity or the unpaid principal balance of the assets covered by our guaranty. However, our securities issued by Fannie Mae multi-class resecuritization trusts that are not consolidated do not give rise to any additional exposure to loss as we already consolidate the underlying collateral. The maximum exposure to loss related to unconsolidated mortgage-backed trusts was $34 billion and $45 billion as of December 31, 2015 and 2014, respectively. The total assets of our unconsolidated mortgage-backed trusts were approximately $220 billion and $250 billion as of December 31, 2015 and 2014, respectively. The total assets of our unconsolidated limited partnership investments were $4.9 billion and $5.8 billion as of December 31, 2015 and 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 years ended December 31, 2015 , 2014 and 2013 , the unpaid principal balance of portfolio securitizations was $212.0 billion , $160.4 billion and $228.5 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 December 31, 2015 , the unpaid principal balance of retained interests was $5.5 billion and its related fair value was $6.8 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 years ended December 31, 2015 , 2014 and 2013 , the principal and interest received on retained interests was $1.2 billion , $1.5 billion and $1.7 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 December 31, 2015 and 2014 , respectively. For information on our on-balance sheet mortgage loans, see “Note 3, Mortgage Loans.”

Mortgage Loans

Mortgage Loans	12 Months Ended
	Dec. 31, 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 consolidated statements of operations and comprehensive income. We define the recorded investment of HFI loans as unpaid principal balance, net of unamortized premiums and discounts, other cost basis adjustments, and accrued interest receivable. For purposes of the single-family mortgage loan disclosures below, we define “primary” class as mortgage loans that are not included in other loan classes; “government” class as mortgage loans 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 December 31, 2015 2014 Of Fannie Mae Of Consolidated Trusts Total Of Fannie Mae Of Consolidated Trusts Total (Dollars in millions) Single-family $ 238,237 $ 2,574,174 $ 2,812,411 $ 262,116 $ 2,569,884 $ 2,832,000 Multifamily 13,099 185,243 198,342 23,255 164,045 187,300 Total unpaid principal balance of mortgage loans 251,336 2,759,417 3,010,753 285,371 2,733,929 3,019,300 Cost basis and fair value adjustments, net (12,939 ) 49,781 36,842 (12,705 ) 48,440 35,735 Allowance for loan losses for loans held for investment (26,510 ) (1,441 ) (27,951 ) (33,117 ) (2,424 ) (35,541 ) Total mortgage loans $ 211,887 $ 2,807,757 $ 3,019,644 $ 239,549 $ 2,779,945 $ 3,019,494 For the years ended December 31, 2015 , 2014 and 2013 , we redesignated loans with a carrying value of $8.6 billion , $2.2 billion and $1.3 billion , respectively, from HFI to HFS. For the year ended December 31, 2014 , we redesignated loans with a carrying value of $285 million from HFS to HFI. We sold loans with an unpaid principal balance of $3.6 billion , $1.9 billion and $1.2 billion , respectively, during the years ended December 31, 2015 , 2014 and 2013 . The recorded investment of single-family mortgage loans for which formal foreclosure proceedings are in process was $25.6 billion as of December 31, 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. 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 December 31, 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 $ 29,154 $ 7,937 $ 26,346 $ 63,437 $ 2,598,756 $ 2,662,193 $ 46 $ 34,216 Government (2) 58 24 291 373 40,461 40,834 291 — Alt-A 4,085 1,272 6,141 11,498 84,603 96,101 6 7,407 Other 1,494 484 2,160 4,138 32,272 36,410 6 2,632 Total single-family 34,791 9,717 34,938 79,446 2,756,092 2,835,538 349 44,255 Multifamily (3) 23 N/A 123 146 200,028 200,174 — 591 Total $ 34,814 $ 9,717 $ 35,061 $ 79,592 $ 2,956,120 $ 3,035,712 $ 349 $ 44,846 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 NA 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 December 31, 2015 (1) 2014 (1) Primary Alt-A Other Primary Alt-A Other (Dollars in millions) Estimated mark-to-market LTV ratio: (2) Less than or equal to 80% $ 2,228,533 $ 59,000 $ 21,274 $ 2,156,165 $ 60,851 $ 22,558 Greater than 80% and less than or equal to 90% 250,373 12,588 4,936 261,709 15,151 6,046 Greater than 90% and less than or equal to 100% 122,939 9,345 3,861 140,778 12,490 5,236 Greater than 100% and less than or equal to 110% 27,875 6,231 2,596 43,014 8,998 3,900 Greater than 110% and less than or equal to 120% 14,625 3,730 1,592 23,439 6,033 2,615 Greater than 120% and less than or equal to 125% 4,520 1,260 545 7,529 2,114 904 Greater than 125% 13,328 3,947 1,606 23,586 7,124 3,000 Total $ 2,662,193 $ 96,101 $ 36,410 $ 2,656,220 $ 112,761 $ 44,259 __________ (1) Excludes $40.8 billion and $45.3 billion as of December 31, 2015 and 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 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 December 31, 2015 2014 (Dollars in millions) Credit risk profile by internally assigned grade: (1) Pass $ 194,132 $ 182,079 Special Mention 3,202 3,070 Substandard 2,833 3,842 Doubtful 7 242 Total $ 200,174 $ 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 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 December 31, 2015 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 (1) (Dollars in millions) Individually impaired loans: With related allowance recorded: Single-family: Primary $ 116,477 $ 110,502 $ 16,745 $ 125,960 $ 120,221 $ 20,327 $ 309 Government 322 327 59 281 285 46 12 Alt-A 31,888 29,103 6,217 35,492 32,816 7,778 136 Other 12,893 12,179 2,416 14,667 13,947 3,049 38 Total single-family 161,580 152,111 25,437 176,400 167,269 31,200 495 Multifamily 650 654 80 1,230 1,241 175 6 Total individually impaired loans with related allowance recorded 162,230 152,765 25,517 177,630 168,510 31,375 501 With no related allowance recorded: (2) Single-family: Primary 15,891 14,725 — 16,704 14,876 — — Government 58 54 — 61 57 — — Alt-A 3,721 3,169 — 3,993 3,119 — — Other 1,222 1,102 — 1,240 1,056 — — Total single-family 20,892 19,050 — 21,998 19,108 — — Multifamily 353 354 — 565 568 — — Total individually impaired loans with no related allowance recorded 21,245 19,404 — 22,563 19,676 — — Total individually impaired loans (3) $ 183,475 $ 172,169 $ 25,517 $ 200,193 $ 188,186 $ 31,375 $ 501 For the Year Ended December 31, 2015 2014 2013 Average Recorded Investment Total Interest Income Recognized (4) Interest Income Recognized on a Cash Basis Average Recorded Investment Total Interest Income Recognized (4) Interest Income Recognized on a Cash Basis Average Recorded Investment Total Interest Income Recognized (4) Interest Income Recognized on a Cash Basis (Dollars in millions) Individually impaired loans: With related allowance recorded: Single-family: Primary $ 114,737 $ 4,190 $ 318 $ 121,926 $ 4,321 $ 494 $ 124,659 $ 4,351 $ 603 Government 299 12 — 270 13 — 213 11 — Alt-A 30,453 1,034 54 33,676 1,066 100 35,075 1,096 135 Other 12,863 376 21 14,490 402 36 15,537 425 52 Total single-family 158,352 5,612 393 170,362 5,802 630 175,484 5,883 790 Multifamily 973 16 — 1,699 80 1 2,552 128 1 Total individually impaired loans with related allowance recorded 159,325 5,628 393 172,061 5,882 631 178,036 6,011 791 With no related allowance recorded: (2) Single-family: Primary 15,796 1,039 91 13,852 864 215 11,442 1,369 227 Government 55 4 — 67 5 — 112 8 — Alt-A 3,647 218 11 2,799 189 47 2,207 329 45 Other 1,259 75 3 974 56 12 752 117 17 Total single-family 20,757 1,336 105 17,692 1,114 274 14,513 1,823 289 Multifamily 442 10 — 1,472 64 — 1,863 97 3 Total individually impaired loans with no related allowance recorded 21,199 1,346 105 19,164 1,178 274 16,376 1,920 292 Total individually impaired loans (3) $ 180,524 $ 6,974 $ 498 $ 191,225 $ 7,060 $ 905 $ 194,412 $ 7,931 $ 1,083 __________ (1) Effective January 1, 2015, we charged off accrued interest receivable associated with loans on nonaccrual status in connection with our adoption of a change in accounting policy related to the treatment of interest previously accrued, but not collected, at the date that loans are placed on nonaccrual status. See “ Note 1, Summary of Significant Accounting Policies ” for additional information. (2) The discounted cash flows or collateral value equals or exceeds the carrying value of the loan and, as such, no valuation allowance is required. (3) Includes single-family loans restructured in a TDR with a recorded investment of $170.3 billion , $185.2 billion and $187.6 billion as of December 31, 2015 , 2014 and 2013 , respectively. Includes multifamily loans restructured in a TDR with a recorded investment of $451 million , $716 million and $911 million as of December 31, 2015 , 2014 and 2013 , respectively. (4) Total single-family interest income recognized of $6.9 billion for the year ended December 31, 2015 consists of $5.7 billion of contractual interest and $1.2 billion of effective yield adjustments. Total single-family interest income recognized of $6.9 billion for the year ended December 31, 2014 consists of $5.8 billion of contractual interest and $1.1 billion of effective yield adjustments. Total single-family interest income recognized of $7.7 billion for the year ended December 31, 2013 consists of $5.7 billion of contractual interest and $2.0 billion of effective yield adjustments. Troubled Debt Restructurings A modification to the contractual terms of a loan that results in granting a concession to a borrower experiencing financial difficulties is considered a TDR. 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. The average term extension of a single-family modified loan was 161 months for the years ended December 31, 2015 and 2014 and 154 months for the year ended December 31, 2013. The average interest rate reduction was 0.74 , 0.99 and 1.68 percentage points for the years ended December 31, 2015 , 2014 and 2013, respectively. The following table displays the number of loans and recorded investment in loans restructured in a TDR. For the Year Ended December 31, 2015 2014 2013 Number of Loans Recorded Investment Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 71,293 $ 9,713 100,956 $ 14,301 126,998 $ 19,016 Government 241 27 365 47 312 35 Alt-A 9,037 1,374 14,715 2,441 21,471 3,794 Other 1,835 333 3,357 686 6,226 1,378 Total single-family 82,406 11,447 119,393 17,475 155,007 24,223 Multifamily 12 40 19 853 33 213 Total TDRs 82,418 $ 11,487 119,412 $ 18,328 155,040 $ 24,436 The following table displays 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 Year Ended December 31, 2015 2014 2013 Number of Loans Recorded Investment Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 26,206 $ 3,808 33,853 $ 5,095 45,539 $ 6,978 Government 118 16 124 15 130 17 Alt-A 4,128 706 5,392 960 9,601 1,732 Other 1,229 247 1,738 387 3,093 685 Total single-family 31,681 4,777 41,107 6,457 58,363 9,412 Multifamily 3 6 9 42 9 64 Total TDRs that subsequently defaulted 31,684 $ 4,783 41,116 $ 6,499 58,372 $ 9,476

Allowance for Loan Losses

Allowance for Loan Losses	12 Months Ended
	Dec. 31, 2015
Loans and Leases Receivable, Allowance [Abstract]
Allowance for Loan Losses	Allowance for Loan Losses We maintain an allowance for loan losses for HFI loans held by Fannie Mae and loans backing Fannie Mae MBS issued from consolidated trusts. When calculating our allowance for loan losses, we consider our net recorded investment in the loan at the balance sheet date, which includes unpaid principal balance, net of amortized premiums and discounts, and other cost basis adjustments. The following table displays changes in single-family, multifamily and total allowance for loan losses. For the Year Ended December 31, 2015 2014 2013 Of Fannie Mae Of Consolidated Trusts Total 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 $ 49,848 $ 7,839 $ 57,687 Provision (benefit) for loan losses (1) (258 ) 190 (68 ) (4,334 ) 553 (3,781 ) (6,751 ) (2,145 ) (8,896 ) Charge-offs (2)(3) (9,647 ) (84 ) (9,731 ) (6,168 ) (225 ) (6,393 ) (8,458 ) (256 ) (8,714 ) Recoveries 1,120 16 1,136 1,190 250 1,440 2,115 511 2,626 Transfers (4) 1,123 (1,123 ) — 1,513 (1,513 ) — 2,932 (2,932 ) — Other (5) 1,145 50 1,195 553 51 604 516 88 604 Ending balance $ 26,439 $ 1,270 $ 27,709 $ 32,956 $ 2,221 $ 35,177 $ 40,202 $ 3,105 $ 43,307 Multifamily allowance for loan losses: Beginning balance $ 161 $ 203 $ 364 $ 319 $ 220 $ 539 $ 671 $ 437 $ 1,108 Benefit for loan losses (1) (63 ) (27 ) (90 ) (91 ) (13 ) (104 ) (233 ) (187 ) (420 ) Charge-offs (2)(3) (40 ) (3 ) (43 ) (76 ) — (76 ) (153 ) — (153 ) Recoveries 4 — 4 — — — — — — Transfers (4) 4 (4 ) — 4 (4 ) — 30 (30 ) — Other (5) 5 2 7 5 — 5 4 — 4 Ending balance $ 71 $ 171 $ 242 $ 161 $ 203 $ 364 $ 319 $ 220 $ 539 Total allowance for loan losses: Beginning balance $ 33,117 $ 2,424 $ 35,541 $ 40,521 $ 3,325 $ 43,846 $ 50,519 $ 8,276 $ 58,795 Provision (benefit) for loan losses (1) (321 ) 163 (158 ) (4,425 ) 540 (3,885 ) (6,984 ) (2,332 ) (9,316 ) Charge-offs (2)(3) (9,687 ) (87 ) (9,774 ) (6,244 ) (225 ) (6,469 ) (8,611 ) (256 ) (8,867 ) Recoveries 1,124 16 1,140 1,190 250 1,440 2,115 511 2,626 Transfers (4) 1,127 (1,127 ) — 1,517 (1,517 ) — 2,962 (2,962 ) — Other (5) 1,150 52 1,202 558 51 609 520 88 608 Ending balance $ 26,510 $ 1,441 $ 27,951 $ 33,117 $ 2,424 $ 35,541 $ 40,521 $ 3,325 $ 43,846 __________ (1) Provision (benefit) for loan losses is included in “Benefit for credit losses” in our 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, for the year ended December 31, 2015 , charge-offs of (1) $1.8 billion in loans held for investment 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 in connection with our adoption of a change in accounting policy 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. (4) Includes transfers from trusts for delinquent loan purchases. (5) Amounts represent changes in other loss reserves which are reflected in provision (benefit) for loan losses, charge-offs, and recoveries. The following table displays the allowance for loan losses and recorded investment in our HFI loans, excluding loans for which we have elected the fair value option, by impairment or reserve methodology and portfolio segment. As of December 31, 2015 2014 Single-Family Multifamily Total Single-Family Multifamily Total (Dollars in millions) Allowance for loan losses by segment: Individually impaired loans (1) $ 25,437 $ 80 $ 25,517 $ 31,200 $ 175 $ 31,375 Collectively reserved loans 2,272 162 2,434 3,977 189 4,166 Total allowance for loan losses $ 27,709 $ 242 $ 27,951 $ 35,177 $ 364 $ 35,541 Recorded investment in loans by segment: Individually impaired loans (1) $ 171,161 $ 1,008 $ 172,169 $ 186,377 $ 1,809 $ 188,186 Collectively reserved loans 2,664,377 199,166 2,863,543 2,672,184 187,424 2,859,608 Total recorded investment in loans $ 2,835,538 $ 200,174 $ 3,035,712 $ 2,858,561 $ 189,233 $ 3,047,794 __________ (1) Includes acquired credit-impaired loans.

Investments in Securities

Investments in Securities	12 Months Ended
	Dec. 31, 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 consolidated statements of operations and comprehensive income. The following table displays our investments in trading securities. As of December 31, 2015 2014 (Dollars in millions) Mortgage-related securities: Fannie Mae $ 4,813 $ 4,940 Freddie Mac 1,314 1,369 Ginnie Mae 426 166 Alt-A private-label securities 436 920 Subprime private-label securities 644 1,307 Commercial mortgage-backed securities (“CMBS”) 2,341 2,515 Mortgage revenue bonds 449 722 Other mortgage-related securities — 99 Total mortgage-related securities 10,423 12,038 U.S. Treasury securities 29,485 19,466 Total trading securities $ 39,908 $ 31,504 The following table displays information about our net trading gains and losses. For the Year Ended December 31, 2015 2014 2013 (Dollars in millions) Net trading gains (losses) $ (368 ) $ 485 $ 260 Net trading gains (losses) recognized in the period related to securities still held at period end (453 ) 420 297 Available-for-Sale Securities We record 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 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 Year Ended December 31, 2015 2014 2013 (Dollars in millions) Gross realized gains $ 1,066 $ 569 $ 1,632 Gross realized losses 70 5 979 Total proceeds (excludes initial sale of securities from new portfolio securitizations) 8,023 3,265 15,157 The following tables display the amortized cost, gross unrealized gains and losses, and fair value by major security type for AFS securities in our retained mortgage portfolio. As of December 31, 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 $ 4,008 $ 243 $ — $ (30 ) $ 4,221 Freddie Mac 4,000 299 — — 4,299 Ginnie Mae 343 48 — — 391 Alt-A private-label securities 2,029 653 (4 ) — 2,678 Subprime private-label securities 2,526 759 — (4 ) 3,281 CMBS 1,235 20 — — 1,255 Mortgage revenue bonds 2,639 99 (29 ) (8 ) 2,701 Other mortgage-related securities 1,361 49 (6 ) — 1,404 Total $ 18,141 $ 2,170 $ (39 ) $ (42 ) $ 20,230 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 s __________ (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 consolidated statements of operations and comprehensive income. (2) Represents the noncredit component of OTTI losses recorded in “Accumulated other comprehensive income” in our 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 December 31, 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 $ (8 ) $ 659 $ (22 ) $ 491 Alt-A private-label securities (1 ) 26 (3 ) 54 Subprime private-label securities — 12 (4 ) 91 Mortgage revenue bonds (35 ) 631 (2 ) 22 Other mortgage-related securities (6 ) 224 — — Total $ (50 ) $ 1,552 $ (31 ) $ 658 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 For AFS securities, OTTI is considered to have occurred when the fair value of a debt security is below its amortized cost basis and we intend to sell or it is more likely than not that we will be required to sell the security before recovery. Additionally, OTTI is considered to have occurred if we do not expect to recover the entire amortized cost basis of a debt security even if we do not intend to sell the security or it is not more likely than not we will be required to sell the security before recovery. We recognized $ 196 million , $ 90 million and $ 64 million of OTTI for the years ended December 31, 2015 , 2014 and 2013 , respectively, which are included in “Investment gains, net” in our consolidated statements of operations and comprehensive income. OTTI recognized for the year ended December 31, 2015 increased compared with the year ended December 31, 2014 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 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 December 31, 2015 Alt-A Subprime Option ARM Fixed Rate Variable Rate Hybrid Rate (Dollars in millions) Unpaid principal balance $ 4,367 $ 434 $ 817 $ 805 $ 987 Weighted average collateral default (1) 41.2 % 28.2 % 12.0 % 20.4 % 8.6 % Weighted average collateral severities (2) 58.8 34.4 45.0 37.3 33.1 Weighted average voluntary prepayment rates (3) 2.7 7.5 11.6 8.7 12.5 Average credit enhancement (4) 18.2 3.6 7.2 8.7 4.3 __________ (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 consolidated statements of operations and comprehensive income. For the Year Ended December 31, 2015 2014 (Dollars in millions) Balance, beginning of period $ 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 8 58 Reductions for securities no longer in portfolio at period end (1,171 ) (904 ) 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 (1,492 ) (1,453 ) Reductions for amortization resulting from changes in cash flows expected to be collected over the remaining life of the securities (184 ) (346 ) Balance, end of period $ 2,421 $ 5,260 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 December 31, 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 $ 4,008 $ 4,221 $ — $ — $ 160 $ 164 $ 114 $ 123 $ 3,734 $ 3,934 Freddie Mac 4,000 4,299 1 1 185 192 310 337 3,504 3,769 Ginnie Mae 343 391 — — 1 1 61 68 281 322 Alt-A private-label securities 2,029 2,678 — — — — — — 2,029 2,678 Subprime private-label securities 2,526 3,281 — — — — — — 2,526 3,281 CMBS 1,235 1,255 278 280 899 917 — — 58 58 Mortgage revenue bonds 2,639 2,701 11 11 112 113 202 205 2,314 2,372 Other mortgage-related securities 1,361 1,404 — — — — 29 30 1,332 1,374 Total $ 18,141 $ 20,230 $ 290 $ 292 $ 1,357 $ 1,387 $ 716 $ 763 $ 15,778 $ 17,788 Weighted average yield (1) 4.94 % 4.36 % 4.51 % 6.28 % 4.93 % __________ (1) Yields are determined by dividing interest income (including amortization and accretion of premiums, discounts and other cost basis adjustments) by amortized cost balances as of year-end. Yields on tax-exempt obligations have been computed on a tax equivalent basis.

Financial Guarantees

Financial Guarantees	12 Months Ended
	Dec. 31, 2015
Guarantees [Abstract]
Financial Guarantees	Financial Guarantees We generate revenue by absorbing the credit risk of mortgage loans in unconsolidated trusts in exchange for a guaranty fee. We also provide credit enhancements on taxable or tax-exempt mortgage revenue bonds issued by state and local governmental entities to finance multifamily housing for low- and moderate-income families. Additionally, we issue long-term standby commitments that generally require us to purchase loans from lenders if the loans meet certain delinquency criteria. 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 11 days 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 consolidated balance sheets and the maximum potential recovery from third parties through available credit enhancements and recourse related to our financial guarantees. As of December 31, 2015 2014 Maximum Exposure (1) Guaranty Obligation Maximum Recovery (2) Maximum Exposure (1) Guaranty Obligation Maximum Recovery (2) (Dollars in millions) Unconsolidated Fannie Mae MBS $ 15,069 $ 194 $ 8,857 $ 17,184 $ 214 $ 9,775 Other guaranty arrangements (3) 16,504 135 2,869 18,781 168 4,447 Total $ 31,573 $ 329 $ 11,726 $ 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 and financial guarantors, see “ Note 15, Concentrations of Credit Risk .” (3) Primarily consists of credit enhancements, long-term standby commitments, and our commitment under the TCLF program.

Acquired Property, Net

Acquired Property, Net	12 Months Ended
	Dec. 31, 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, are actively marketing it and it is ready for immediate sale in its current condition. The following table displays the activity in acquired property, and related valuation allowance. For the Year Ended December 31, 2015 2014 2013 (Dollars in millions) Beginning balance — Acquired property $ 11,442 $ 12,307 $ 11,158 Additions 9,382 13,100 16,092 Disposals (13,343 ) (13,965 ) (14,943 ) Ending balance — Acquired property 7,481 11,442 12,307 Beginning balance — Valuation allowance (824 ) (686 ) (669 ) Decrease (increase) in valuation allowance 109 (138 ) (17 ) Ending balance — Valuation allowance (715 ) (824 ) (686 ) Ending balance — Acquired property, net $ 6,766 $ 10,618 $ 11,621 We classify as held for use those properties that we do not intend to sell or that are not ready for immediate sale in their current condition, which are included in “Other assets” in our consolidated balance sheets. For the years ended December 31, 2015, 2014 and 2013, the carrying amount of acquired property held for use was $ 85 million , $ 135 million and $ 256 million , respectively.

Short-Term Borrowings and Long-

Short-Term Borrowings and Long-Term Debt	12 Months Ended
	Dec. 31, 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 December 31, 2015 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) $ 62 — % $ 50 — % Short-term debt of Fannie Mae $ 71,007 0.26 % $ 105,012 0.11 % Debt of consolidated trusts 943 0.19 1,560 0.09 Total short-term debt $ 71,950 0.26 % $ 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 December 31, 2015 and 2014. We had no borrowings outstanding under this line of credit as of December 31, 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 December 31, 2015 2014 Maturities Outstanding Weighted- Average Interest Rate (1) Maturities Outstanding Weighted- Average Interest Rate (1) (Dollars in millions) Senior fixed: Benchmark notes and bonds 2016 - 2030 $ 154,057 2.49 % 2015 - 2030 $ 173,010 2.41 % Medium-term notes (2) 2016 - 2025 96,997 1.53 2015 - 2024 114,556 1.42 Other (3) 2016 - 2038 27,772 4.88 2015 - 2038 32,941 4.65 Total senior fixed 278,826 2.39 320,507 2.29 Senior floating: Medium-term notes (2) 2016 - 2019 20,791 0.27 2015 - 2019 24,469 0.15 Connecticut Avenue Securities (4) 2023 - 2028 10,764 3.84 2023 - 2024 6,041 2.97 Other (5) 2020 - 2037 368 10.46 2020 - 2037 363 8.71 Total senior floating 31,923 1.58 30,873 0.81 Subordinated debentures 2019 4,227 9.93 2019 3,849 9.93 Secured borrowings (6) 2021 - 2022 152 1.47 2021 - 2022 202 1.90 Total long-term debt of Fannie Mae (7) 315,128 2.41 355,431 2.24 Debt of consolidated trusts 2016 - 2054 2,810,593 2.94 2015 - 2054 2,760,152 3.02 Total long-term debt $ 3,125,721 2.88 % $ 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) Includes other long-term debt and foreign exchange bonds. (4) 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. (5) Consists of structured debt instruments that are reported at fair value. (6) Represents our remaining liability resulting from the transfer of financial assets from our consolidated balance sheets that did not qualify as a sale under the accounting guidance for the transfer of financial instruments. (7) Includes unamortized discounts and premiums, other cost basis adjustments and fair value adjustments of $3.2 billion and $4.1 billion as of December 31, 2015 and 2014 , respectively. Our long-term debt includes a variety of debt types. We issue fixed and floating-rate medium-term notes with maturities greater than one year that are issued through dealer banks. We also offer Benchmark Notes in regularly-scheduled issuances that provide increased efficiency, liquidity and tradability to the market. Additionally, we have issued notes and bonds denominated in several foreign currencies. We effectively convert all foreign currency-denominated transactions into U.S. dollars through the use of foreign currency swaps for the purpose of funding our mortgage assets. Our long-term debt also includes Connecticut Avenue Securities (“CAS”), which are credit risk-sharing securities that transfer a portion of the credit risk on specified pools of mortgage loans to investors in these securities. Our other long-term debt includes callable and non-callable securities, which include all long-term non-Benchmark securities, such as zero-coupon bonds, fixed rate and other long-term securities, and are generally negotiated underwritings with one or more dealers or dealer banks. Characteristics of Debt As of December 31, 2015 and 2014 , the face amount of our debt securities of Fannie Mae was $389.4 billion and $464.6 billion , respectively. As of December 31, 2015 and 2014 , we had zero-coupon debt with a face amount of $82.1 billion and $116.7 billion , respectively, which had an effective interest rate of 1.26% and 0.77% , respectively. We issue callable debt instruments to manage the duration and prepayment risk of expected cash flows of the mortgage assets we own. Our outstanding debt as of December 31, 2015 and 2014 included $96.2 billion and $115.0 billion , respectively, of callable debt that could be redeemed in whole or in part at our option any time on or after a specified date. The following table displays the amount of our long-term debt as of December 31, 2015 by year of maturity for each of the years 2016 through 2020 and thereafter. The first column assumes that we pay off this debt at maturity or on the call date if the call has been announced, while the second column assumes that we redeem our callable debt at the next available call date. Long-Term Debt by Year of Maturity Assuming Callable Debt Redeemed at Next Available Call Date (Dollars in millions) 2016 $ 52,829 $ 143,970 2017 76,970 69,351 2018 60,555 32,832 2019 29,656 19,036 2020 30,129 16,658 Thereafter 64,989 33,281 Total debt of Fannie Mae (1) 315,128 315,128 Debt of consolidated trusts (2) 2,810,593 2,810,593 Total long-term debt $ 3,125,721 $ 3,125,721 __________ (1) Includes unamortized discounts and premiums, other cost basis adjustments and fair value adjustments of $3.2 billion . (2) Contractual maturity of debt of consolidated trusts is not a reliable indicator of expected maturity because borrowers of the underlying loans generally have the right to prepay their obligations at any time.

Derivative Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 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 derivative contracts we use for interest rate risk management purposes fall into these broad categories: • Interest rate swap contracts. An interest rate swap is a transaction between two parties in which each party agrees to exchange payments tied to different interest rates or indices for a specified period of time, generally based on a notional amount of principal. The types of interest rate swaps we use include pay-fixed swaps, receive-fixed swaps and basis swaps. • Interest rate option contracts. These contracts primarily include pay-fixed swaptions, receive-fixed swaptions, cancelable swaps and interest rate caps. A swaption is an option contract that allows us or a counterparty to enter into a pay-fixed or receive-fixed swap at some point in the future. • Foreign currency swaps. These swaps convert debt that we issue in foreign denominated currencies into U.S. dollars. We enter into foreign currency swaps only to the extent that we hold foreign currency debt. • Futures. These are standardized exchange-traded contracts that either obligate a buyer to buy an asset at a predetermined date and price or a seller to sell an asset at a predetermined date and price. The types of futures contracts we enter into include Eurodollar, U.S. Treasury and swaps. We enter into various forms of credit risk sharing agreements, including credit risk transfer transactions, swap credit enhancements and mortgage insurance contracts, that we account for as derivatives. The majority of our credit-related derivatives are credit risk transfer transactions, whereby a portion of the credit risk associated with losses on a reference pool of mortgage loans is transferred to a third party. We enter into forward purchase and sale commitments that lock in the future delivery of mortgage loans and mortgage-related securities at a fixed price or yield. Certain commitments to purchase mortgage loans and purchase or sell mortgage-related securities meet the criteria of a derivative. We typically settle the notional amount of our mortgage commitments that are accounted for as derivatives. 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 December 31, 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 $ 33,154 $ 267 $ 123,106 $ (6,920 ) $ 41,965 $ 733 $ 123,557 $ (7,125 ) Receive-fixed 59,796 3,436 143,209 (753 ) 67,629 4,486 157,272 (1,302 ) Basis 1,864 141 17,100 (15 ) 5,769 123 7,100 (2 ) Foreign currency 295 95 258 (52 ) 344 144 273 (30 ) Swaptions: Pay-fixed 7,050 45 14,950 (26 ) 11,100 57 26,525 (175 ) Receive-fixed 2,000 8 13,950 (171 ) 750 96 29,525 (816 ) Other (1) 9,196 28 — (2 ) 1,071 28 12 (1 ) Total gross risk management derivatives 113,355 4,020 312,573 (7,939 ) 128,628 5,667 344,264 (9,451 ) Accrued interest receivable (payable) — 758 — (977 ) — 749 — (1,013 ) Netting adjustment (2) — (4,024 ) — 8,650 — (5,186 ) — 10,194 Total net risk management derivatives $ 113,355 $ 754 $ 312,573 $ (266 ) $ 128,628 $ 1,230 $ 344,264 $ (270 ) Mortgage commitment derivatives: Mortgage commitments to purchase whole loans $ 4,815 $ 9 $ 2,960 $ (9 ) $ 6,157 $ 28 $ 428 $ — Forward contracts to purchase mortgage-related securities 31,273 66 19,418 (57 ) 43,533 223 6,112 (8 ) Forward contracts to sell mortgage-related securities 26,224 65 40,753 (92 ) 4,886 4 57,910 (336 ) Total mortgage commitment derivatives 62,312 140 63,131 (158 ) 54,576 255 64,450 (344 ) Derivatives at fair value $ 175,667 $ 894 $ 375,704 $ (424 ) $ 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 $4.9 billion and $5.3 billion as of December 31, 2015 and 2014 , respectively. Cash collateral received was $314 million and $245 million as of December 31, 2015 and 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 $2.4 billion and $2.6 billion , for which we posted collateral of $2.2 billion and $2.4 billion in the normal course of business as of December 31, 2015 and 2014 , respectively. Had all of the credit-risk-related contingency features underlying these agreements been triggered, an additional $257 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 December 31, 2015 and 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 derivatives contracts. We record all derivative gains and losses, including accrued interest, in “Fair value gains (losses), net” in our 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 Year Ended December 31, 2015 2014 2013 (Dollars in millions) Risk management derivatives: Swaps: Pay-fixed $ (746 ) $ (7,703 ) $ 14,393 Receive-fixed 625 4,229 (10,721 ) Basis 4 85 (115 ) Foreign currency (60 ) 27 (101 ) Swaptions: Pay-fixed 135 (4 ) (238 ) Receive-fixed (93 ) (197 ) 307 Other (25 ) 1 21 Accrual of periodic settlements: Pay-fixed interest-rate swaps (3,602 ) (3,712 ) (4,463 ) Receive-fixed interest-rate swaps 2,603 2,600 3,632 Other 39 50 64 Total risk management derivatives fair value gains (losses), net (1,120 ) (4,624 ) 2,779 Mortgage commitment derivatives fair value gains (losses), net (393 ) (1,140 ) 501 Total derivatives fair value gains (losses), net $ (1,513 ) $ (5,764 ) $ 3,280 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 16, Netting Arrangements ” for information on our rights to offset assets and liabilities as of December 31, 2015 and 2014.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Tax	Income Taxes Provision (Benefit) for Income Taxes We are subject to federal income tax, but we are exempt from state and local income taxes. The following table displays the components of our provision (benefit) for federal income taxes. For the Year Ended December 31, 2015 2014 2013 (Dollars in millions) Current income tax provision (benefit) $ (271 ) $ 1,879 $ 3,067 Deferred income tax provision (benefit) (1) 5,524 5,062 (48,482 ) Provision (benefit) for federal income taxes $ 5,253 $ 6,941 $ (45,415 ) __________ (1) Amount excludes the income tax effect of items recognized directly in “Fannie Mae stockholders’ equity.” Current income tax benefit for the year ended December 31, 2015 reflects the recognition of a $1.4 billion income tax receivable expected from an amended federal tax return primarily related to deductions for charged-off nonaccrued interest. This amount was fully offset by a corresponding $1.4 billion decrease in our deferred tax assets resulting in an increase in our deferred income tax provision. The following table displays the difference between our effective tax rate and the statutory federal tax rate. For the Year Ended December 31, 2015 2014 2013 Statutory corporate tax rate 35.0 % 35.0 % 35.0 % Equity investments in affordable housing projects (2.6 ) (1.8 ) (1.5 ) Other 0.9 1.4 — Valuation allowance (0.9 ) (1.8 ) (151.3 ) Effective tax rate 32.4 % 32.8 % (117.8 ) % Our effective tax rate is the provision (benefit) for federal income taxes expressed as a percentage of income or loss before federal income taxes. Our effective tax rate was different from the federal statutory rate of 35% for the years ended December 31, 2015 and 2014 primarily due to the benefits of our investments in housing projects eligible for low-income housing tax credits. The decrease in our deferred tax valuation allowance in 2015 reflects the utilization of our capital loss carryforwards due to recognition of net capital gains, which allowed us to release the corresponding valuation allowance against our capital loss carryforwards. The decrease in our deferred tax valuation allowance in 2014 reflects the expiration of certain capital loss carryforwards that are included as a component of “Other” in the table above. Our effective tax rate was different from the federal statutory rate of 35% for the year ended December 31, 2013 primarily due to the release of our valuation allowance for our net deferred tax assets that resulted in the recognition of $58.3 billion benefit in our provision (benefit) for income taxes. Deferred Tax Assets and Liabilities We recognize deferred tax assets and liabilities for future tax consequences arising from differences between the carrying amounts of existing assets and liabilities under GAAP and their respective tax bases. We evaluate our deferred tax assets for recoverability using a consistent approach which considers the relative impact of negative and positive evidence, including our historical profitability and projections of future taxable income. As of December 31, 2015 , we continued to conclude that the positive evidence in favor of the recoverability of our deferred tax asset outweighed the negative evidence and that it is more likely than not that our deferred tax assets will be realized. Our framework for assessing the recoverability of deferred tax assets requires us to weigh all available evidence, including the sustainability of recent profitability required to realize the deferred tax assets; the cumulative net income or losses in our consolidated statements of operations and comprehensive income in recent years; unsettled circumstances that, if unfavorably resolved, would adversely affect future operations and profit levels on a continuing basis in future years; the funding available to us under the senior preferred stock purchase agreement; and the carryforward periods for any carryforwards of net operating losses, if any, capital losses and tax credits. The following table displays our deferred tax assets, deferred tax liabilities and valuation allowance. As of December 31, 2015 2014 (Dollars in millions) Deferred tax assets: Mortgage and mortgage-related assets $ 16,956 $ 16,250 Allowance for loan losses and basis in acquired property, net 11,760 17,435 Debt and derivative instruments 3,512 4,254 Partnership credits 3,402 2,918 Partnership and other equity investments 745 934 Other, net 1,543 1,699 Total deferred tax assets 37,918 43,490 Deferred tax liabilities: Unrealized gains on AFS securities, net 731 1,134 Total deferred tax liabilities 731 1,134 Valuation allowance — (150 ) Deferred tax assets, net $ 37,187 $ 42,206 As of December 31, 2015 , we had no net operating loss carryforwards. We had a remaining balance of $3.4 billion of partnership tax credit carryforwards that expire in various years through 2035 and $308 million of alternative minimum tax credit carryforwards that have an indefinite carryforward period. Unrecognized Tax Benefits The following table displays the changes in our unrecognized tax benefits. For the Year Ended December 31, 2015 2014 2013 (Dollars in millions) Unrecognized tax benefits as of January 1 $ 213 $ 514 $ 648 Gross decreases—tax positions in prior years (213 ) (301 ) (134 ) Unrecognized tax benefits as of December 31 (1) $ — $ 213 $ 514 __________ (1) Amounts exclude tax credits of $91 million and $220 million as of December 31, 2014 and 2013, respectively.

Loss Per Share

Loss Per Share	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Loss Per Share	Loss Per Share The following table displays the computation of basic and diluted loss per share of common stock. For the Year Ended December 31, 2015 2014 2013 (Dollars and shares in millions, except per share amounts) Net income $ 10,955 $ 14,209 $ 83,982 Less: Net income attributable to noncontrolling interest (1 ) (1 ) (19 ) Net income attributable to Fannie Mae 10,954 14,208 83,963 Dividends distributed or available for distribution to senior preferred stockholder (1) (11,216 ) (15,323 ) (85,419 ) Net loss attributable to common stockholders $ (262 ) $ (1,115 ) $ (1,456 ) Weighted-average common shares outstanding—basic and diluted (2) 5,762 5,762 5,762 Loss per share: basic and diluted $ (0.05 ) $ (0.19 ) $ (0.25 ) __________ (1) Dividends distributed or available for distribution were calculated based on our net worth as of the end of the fiscal quarters for each respective year, less the applicable capital reserve. See “Note 1, Summary of Significant Accounting Policies” for additional information on our senior preferred stock agreement and our payment of dividends to Treasury. (2) Includes 4.6 billion for the years ended December 31, 2015, 2014 and 2013, 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 December 31, 2015, 2014 and 2013, respectively.

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 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 structure, the sum of the results for our three business segments does not equal our consolidated results of operations as we separate the activity related to our consolidated trusts from the results generated by our three segments. In addition, we apply accounting methods for segment reporting purposes that differ from our consolidated results. Therefore, we reconcile the sum of the results for our three business segments to our consolidated results of operations. The section below provides a discussion of the three business segments and how each segment’s financial information reconciles to our consolidated financial statements. Single-Family The primary source of revenue for our Single-Family business is the guaranty fees the segment receives as compensation for assuming the credit risk on the mortgage loans underlying single-family Fannie Mae MBS, most of which are held within consolidated trusts, and on the single-family mortgage loans held in our retained mortgage portfolio. The primary source of profit for the Single-Family segment is the difference between the guaranty fees earned and the costs of providing the guaranty, including credit-related expense. Our segment reporting presentation differs from our consolidated balance sheets and statements of operations and comprehensive income in order to reflect the activities and results of the Single-Family segment. The significant differences from the consolidated statements of operations and comprehensive income are as follows: • Guaranty fee income —Guaranty fee income reflects the cash guaranty fees paid by MBS trusts to Single-Family, the amortization of deferred cash fees (both the previously recorded deferred cash fees that were eliminated from our consolidated balance sheets upon adoption of the consolidation accounting guidance on January 1, 2010 and deferred guaranty fees received subsequent to that adoption are currently recognized in our consolidated financial statements through interest income), such as buy-ups, buy-downs, and risk-based pricing adjustments, and the guaranty fees from the Capital Markets group on single-family loans in our retained mortgage portfolio. To reconcile to our consolidated statements of operations and comprehensive income, we eliminate guaranty fees and the amortization of deferred cash fees related to consolidated trusts as they are now reflected as a component of interest income; however, such accounting continues to be reflected for the segment reporting presentation. • Net interest income or loss —Net interest income or loss within the Single-Family segment reflects interest expense to reimburse Capital Markets and consolidated trusts for contractual interest not received on mortgage loans, when interest income is no longer recognized in accordance with our nonaccrual accounting policy in our consolidated statements of operations and comprehensive income. Net interest income (loss), also includes an allocated cost of capital charge among the three segments that is not included in net interest income in the consolidated statements of operations and comprehensive income. Multifamily The primary sources of revenue for our Multifamily business are guaranty fees the segment receives as compensation for assuming the credit risk on the mortgage loans underlying multifamily Fannie Mae MBS, most of which are held within consolidated trusts, guaranty fees on the multifamily mortgage loans held in our retained mortgage portfolio and other fees associated with multifamily business activities. Partnership investments in rental and for-sale housing generate revenue and losses from operations and the eventual sale of the assets. Our segment reporting presentation differs from our consolidated balance sheets and statements of operations and comprehensive income in order to reflect the activities and results of the Multifamily segment. The significant differences from the consolidated statements of operations and comprehensive income are as follows: • Guaranty fee income —Guaranty fee income reflects the cash guaranty fees paid by MBS trusts to Multifamily and the guaranty fees from the Capital Markets group on multifamily loans in Fannie Mae’s portfolio. To reconcile to our consolidated statements of operations and comprehensive income, we eliminate guaranty fees related to consolidated trusts. • Gains or losses from partnership investments —Gains from partnership investments primarily reflect gains or losses on investments in affordable rental and for-sale housing partnerships measured under the equity method of accounting. To reconcile to our consolidated statements of operations and comprehensive income, we adjust the gains or losses to reflect the consolidation of certain partnership investments. Capital Markets Group Our Capital Markets group generates most of its revenue from the difference, or spread, between the interest we earn on the mortgage assets in our retained mortgage portfolio and the interest we pay on the debt we issue to fund these assets. We refer to this spread as our net interest yield. Changes in the fair value of the derivative instruments and trading securities we hold and gains and losses on securitizations and sales of available-for-sale securities from our portfolio impact the net income or loss reported by the Capital Markets group. In addition, a substantial majority of fee and other income for 2013 and 2014 consisted of income resulting from settlement agreements resolving certain lawsuits relating to PLS sold to us. Our segment reporting presentation differs from our consolidated balance sheets and statements of operations and comprehensive income in order to reflect the activities and results of the Capital Markets group. The significant differences from the consolidated statements of operations and comprehensive income are as follows: • Net interest income —Net interest income reflects the interest income on mortgage loans and securities owned by Fannie Mae and interest expense on funding debt issued by Fannie Mae, including accretion and amortization of any cost basis adjustments. To reconcile to our consolidated statements of operations and comprehensive income, we adjust for the impact of consolidated trusts and intercompany eliminations as follows: • Interest income: Interest income consists of interest on the segment’s interest-earning assets, which differs from interest-earning assets in our consolidated balance sheets. We exclude loans and securities that underlie the consolidated trusts from our Capital Markets group balance sheets. The net interest income reported by the Capital Markets group excludes the interest income earned on assets held by consolidated trusts. As a result, we report interest income and amortization of cost basis adjustments only on securities and loans that are held in our retained mortgage portfolio. For mortgage loans held in our retained mortgage portfolio, when interest income is no longer recognized in accordance with our nonaccrual accounting policy, the Capital Markets group recognizes interest income for reimbursement from Single-Family and Multifamily for the contractual interest due under the terms of our intracompany guaranty arrangement. • Interest expense: Interest expense consists of contractual interest on the Capital Markets group’s interest-bearing liabilities, including the accretion and amortization of any cost basis adjustments. It excludes interest expense on debt issued by consolidated trusts. Therefore, the interest expense recognized on the Capital Markets group income statement is limited to our funding debt, which is reported as “Debt of Fannie Mae” in our consolidated balance sheets. Net interest expense also includes an allocated cost of capital charge among the three business segments that is not included in net interest income in our consolidated statements of operations and comprehensive income. • Investment gains or losses, net —Investment gains or losses, net includes the gains and losses on securitizations and sales of available-for-sale securities from our portfolio. To reconcile to our consolidated statements of operations and comprehensive income, we eliminate gains and losses on securities that have been consolidated to loans. • Fair value gains or losses, net —Fair value gains or losses, net for the Capital Markets group includes derivative gains and losses, foreign exchange gains and losses, and the fair value gains and losses on certain debt securities in our portfolio. To reconcile to our consolidated statements of operations and comprehensive income, we eliminate fair value gains or losses on Fannie Mae MBS that have been consolidated to loans. • Other expenses, net —Debt extinguishment gains or losses recorded on the segment statements of operations relate exclusively to our funding debt, which is reported as “Debt of Fannie Mae” in our consolidated balance sheets. To reconcile to our consolidated statements of operations and comprehensive income, we include debt extinguishment gains or losses related to consolidated trusts to arrive at our total recognized debt extinguishment gains or losses. Segment Allocations and Results 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. For the Year Ended December 31, 2015 Business Segments Single-Family Multifamily Capital Markets Reconciling Items (1) Total (Dollars in millions) Net interest income (loss) $ 184 $ (92 ) $ 5,828 $ 15,489 (2) $ 21,409 Benefit for credit losses 688 107 — — 795 Net interest income after benefit for credit losses 872 15 5,828 15,489 22,204 Guaranty fee income (expense) (3) 12,476 1,439 (863 ) (12,924 ) (4) 128 (4) Investment gains (losses), net (2 ) 33 5,539 (4,234 ) (5) 1,336 Fair value gains (losses), net (11 ) — (2,049 ) 293 (6) (1,767 ) Debt extinguishment gains (losses), net (7) — — (37 ) 45 8 Gains (losses) from partnership investments (7) (39 ) 282 — 1 244 Fee and other income 666 265 209 80 1,220 Administrative expenses (2,053 ) (361 ) (636 ) — (3,050 ) Foreclosed property income (expense) (1,723 ) 94 — — (1,629 ) TCCA fees (3) (1,621 ) — — — (1,621 ) Other income (expense) (942 ) (13 ) 8 82 (865 ) Income before federal income taxes 7,623 1,754 7,999 (1,168 ) 16,208 Provision for federal income taxes (2,491 ) (247 ) (2,515 ) — (5,253 ) Net income 5,132 1,507 5,484 (1,168 ) 10,955 Less: Net income attributable to noncontrolling interest — — — (1 ) (8) (1 ) Net income attributable to Fannie Mae $ 5,132 $ 1,507 $ 5,484 $ (1,169 ) $ 10,954 For the Year Ended December 31, 2014 Business Segments Single-Family Multifamily Capital Markets Reconciling Items (1) Total (Dollars in millions) Net interest income (loss) $ 6 $ (79 ) $ 7,243 $ 12,798 (2) $ 19,968 Benefit for credit losses 3,850 114 — — 3,964 Net interest income after benefit for credit losses 3,856 35 7,243 12,798 23,932 Guaranty fee income (expense) (3) 11,702 1,297 (955 ) (11,869 ) (4) 175 (4) Investment gains (losses), net (1 ) 57 6,378 (5,498 ) (5) 936 Fair value gains (losses), net (19 ) — (5,476 ) 662 (6) (4,833 ) Debt extinguishment gains, net (7) — — 35 31 66 Gains (losses) from partnership investments (7) (31 ) 299 — 1 269 Fee and other income 624 166 4,894 28 5,712 Administrative expenses (1,830 ) (306 ) (641 ) — (2,777 ) Foreclosed property income (expense) (225 ) 83 — — (142 ) TCCA fees (3) (1,375 ) — — — (1,375 ) Other income (expense) (726 ) (10 ) (77 ) — (813 ) Income before federal income taxes 11,975 1,621 11,401 (3,847 ) 21,150 Provision for federal income taxes (3,496 ) (158 ) (3,287 ) — (6,941 ) Net income 8,479 1,463 8,114 (3,847 ) 14,209 Less: Net income attributable to noncontrolling interest — — — (1 ) (8) (1 ) Net income attributable to Fannie Mae $ 8,479 $ 1,463 $ 8,114 $ (3,848 ) $ 14,208 For the Year Ended December 31, 2013 Business Segments Single-Family Multifamily Capital Markets Reconciling Items (1) Total (Dollars in millions) Net interest income (loss) $ 205 $ (74 ) $ 9,764 $ 12,509 (2) $ 22,404 Benefit for credit losses 8,469 480 — — 8,949 Net interest income after benefit for credit losses 8,674 406 9,764 12,509 31,353 Guaranty fee income (expense) (3) 10,468 1,217 (1,115 ) (10,365 ) (4) 205 (4) Investment gains (losses), net 3 21 4,847 (3,744 ) (5) 1,127 Fair value gains (losses), net (10 ) — 3,148 (179 ) (6) 2,959 Debt extinguishment gains, net (7) — — 27 104 131 Gains from partnership investments (7) — 498 — 19 517 Fee and other income (expense) 630 182 3,010 (97 ) 3,725 Administrative expenses (1,706 ) (280 ) (559 ) — (2,545 ) Foreclosed property income 2,736 103 — — 2,839 TCCA fees (3) (1,001 ) — — — (1,001 ) Other income (expense) (628 ) (2 ) 20 (133 ) (743 ) Income before federal income taxes 19,166 2,145 19,142 (1,886 ) 38,567 Benefit for federal income taxes (9) 29,110 7,924 8,381 — 45,415 Net income 48,276 10,069 27,523 (1,886 ) 83,982 Less: Net loss attributable to noncontrolling interest — — — (19 ) (8) (19 ) Net income attributable to Fannie Mae $ 48,276 $ 10,069 $ 27,523 $ (1,905 ) $ 83,963 __________ (1) Represents activity related to the assets and liabilities of consolidated trusts in our consolidated balance sheets, and 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. (2) Represents net interest income of consolidated trusts and amortization expense of cost basis adjustments on securities in the Capital Markets group’s mortgage portfolio that on a GAAP basis are eliminated. (3) Reflects the impact of a 10 basis point guaranty fee increase implemented in 2012 pursuant to the TCCA, the incremental revenue from which is remitted to Treasury. The resulting revenue is included in guaranty fee income and the expense is recognized as “TCCA fees.” (4) Represents the guaranty fees paid from consolidated trusts to the Single-Family and Multifamily segments and 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 consolidated statements of operations and comprehensive income. (5) 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 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. (6) Represents the removal of fair value adjustments on consolidated Fannie Mae MBS classified as trading that are in the Capital Markets group’s mortgage portfolio. (7) Debt extinguishment gains, net and gains (losses) from partnership investments are included in other expenses in our consolidated statements of operations and comprehensive income. (8) Represents the adjustment from equity method accounting to consolidation accounting for partnership investments that are consolidated in our consolidated balance sheets. (9) Primarily represents the release of the valuation allowance for our deferred tax assets that generally are directly attributable to each segment based on the nature of the item. The following table displays total assets by segment. As of December 31, 2015 2014 2013 (Dollars in millions) Single-Family $ 34,911 $ 43,512 $ 41,206 Multifamily 9,947 9,281 10,848 Capital Markets 432,689 510,848 596,436 Reconciling items (1) 2,744,370 2,684,535 2,621,618 Total assets $ 3,221,917 $ 3,248,176 $ 3,270,108 __________ (1) Includes assets of consolidated trusts of $2.8 trillion as of December 31, 2015, 2014 and 2013. Includes the elimination of Fannie Mae MBS in the Capital Markets group’s mortgage portfolio that are issued by consolidated trusts. Also includes the elimination of the allowance for loan losses and fair value losses previously recognized on acquired credit impaired loans as they are not treated as assets for Single-Family and Multifamily segment reporting purposes because these allowances and losses relate to loan assets that are held by the Capital Markets segment and consolidated trusts. We operate our business solely in the United States and its territories, and accordingly, we generate no revenue from and have no assets in geographic locations other than the United States and its territories.

Equity

Equity	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Equity	Equity Common Stock Shares of common stock outstanding, net of shares held as treasury stock, totaled 1.2 billion as of December 31, 2015 and 2014 . During conservatorship, the rights and powers of shareholders are suspended. Accordingly, our common shareholders have no ability to elect directors or to vote on other matters during the conservatorship unless FHFA elects to delegate this authority to them. The senior preferred stock purchase agreement with Treasury prohibits the payment of dividends on common stock without the prior written consent of Treasury. The conservator also has eliminated common stock dividends. In addition, we issued a warrant to Treasury that provides Treasury with the right to purchase for a nominal price shares of our common stock equal to 79.9% of the total number of shares of common stock outstanding on a fully diluted basis on the date of exercise, which would substantially dilute the ownership in Fannie Mae of our common stockholders at the time of exercise. Refer to the “Senior Preferred Stock and Common Stock Warrant” section of this note for more information. Preferred Stock The following table displays our senior preferred stock and preferred stock outstanding. Issued and Outstanding as of December 31, Annual Dividend Rate as of December 31, 2015 2015 2014 Stated Value per Share Title Issue Date Shares Amount Shares Amount Redeemable on or After (Dollars and shares in millions, except per share amounts) Senior Preferred Stock Series 2008-2 September 8, 2008 1 $ 117,149 1 $ 117,149 $ 117,149 (1) N/A (2) N/A (3) Preferred Stock Series D September 30, 1998 3 $ 150 3 $ 150 $ 50 5.250 % September 30, 1999 Series E April 15, 1999 3 150 3 150 50 5.100 April 15, 2004 Series F March 20, 2000 14 690 14 690 50 0.260 (4) March 31, 2002 (5) Series G August 8, 2000 6 288 6 288 50 0.400 (6) September 30, 2002 (5) Series H April 6, 2001 8 400 8 400 50 5.810 April 6, 2006 Series I October 28, 2002 6 300 6 300 50 5.375 October 28, 2007 Series L April 29, 2003 7 345 7 345 50 5.125 April 29, 2008 Series M June 10, 2003 9 460 9 460 50 4.750 June 10, 2008 Series N September 25, 2003 5 225 5 225 50 5.500 September 25, 2008 Series O December 30, 2004 50 2,500 50 2,500 50 7.000 (7) December 31, 2007 Convertible Series 2004-I (8) December 30, 2004 — 2,492 — 2,492 100,000 5.375 January 5, 2008 Series P September 28, 2007 40 1,000 40 1,000 25 4.500 (9) September 30, 2012 Series Q October 4, 2007 15 375 15 375 25 6.750 September 30, 2010 Series R (10) November 21, 2007 21 530 21 530 25 7.625 November 21, 2012 Series S December 11, 2007 280 7,000 280 7,000 25 7.750 (11) December 31, 2010 (12) Series T (13) May 19, 2008 89 2,225 89 2,225 25 8.250 May 20, 2013 Total 556 $ 19,130 556 $ 19,130 __________ (1) Initial stated value per share was $1,000 . Based on our draws of funds under the senior preferred stock purchase agreement with Treasury, the stated value per share on December 31, 2015 was $117,149 . (2) For the dividend period ended December 31, 2015 , the dividend is calculated based on our net worth as of September 30, 2015, less the applicable capital reserve amount of $1.8 billion . The capital reserve amount is $1.2 billion for each dividend period in 2016. The applicable capital reserve amount will continue to be reduced by $600 million each year until it reaches zero on January 1, 2018. For each dividend period beginning in 2018, the dividend amount will be the entire amount of our net worth, if any, as of the end of the immediately preceding fiscal quarter. (3) Any liquidation preference of our senior preferred stock in excess of $1.0 billion may be repaid through an issuance of common or preferred stock, which would require the consent of the conservator and Treasury. The initial $1.0 billion liquidation preference may be repaid only in conjunction with termination of the senior preferred stock purchase agreement. (4) Rate effective March 31, 2014. Variable dividend rate resets every two years at a per annum rate equal to the two-year Constant Maturity U.S. Treasury Rate (“CMT”) minus 0.16% with a cap of 11% per year. (5) Represents initial call date. Redeemable every two years thereafter. (6) Rate effective September 30, 2014. Variable dividend rate resets every two years at a per annum rate equal to the two-year CMT rate minus 0.18% with a cap of 11% per year. (7) Rate effective December 31, 2015 . Variable dividend rate resets quarterly thereafter at a per annum rate equal to the greater of 7.00% or 10-year CMT rate plus 2.375% . (8) Issued and outstanding shares were 24,922 as of December 31, 2015 and 2014. (9) Rate effective December 31, 2015 . Variable dividend rate resets quarterly thereafter at a per annum rate equal to the greater of 4.50% or 3-Month LIBOR plus 0.75% . (10) On November 21, 2007, we issued 20 million shares of preferred stock in the amount of $500 million . Subsequent to the initial issuance, we issued an additional 1.2 million shares in the amount of $30 million on December 14, 2007 under the same terms as the initial issuance. (11) Rate effective December 31, 2015 . Variable dividend rate resets quarterly thereafter at a per annum rate equal to the greater of 7.75% or 3-Month LIBOR plus 4.23% . (12) Represents initial call date. Redeemable every five years thereafter. (13) On May 19, 2008, we issued 80 million shares of preferred stock in the amount of $2.0 billion . Subsequent to the initial issuance, we issued an additional 8 million shares in the amount of $200 million on May 22, 2008 and 1 million shares in the amount of $25 million on June 4, 2008 under the same terms as the initial issuance. As described under “Senior Preferred Stock and Common Stock Warrant,” we issued senior preferred stock that ranks senior to all other series of preferred stock as to both dividends and distributions upon dissolution, liquidation or winding up of the company. The senior preferred stock purchase agreement with Treasury also prohibits the payment of dividends on preferred stock (other than the senior preferred stock) without the prior written consent of Treasury. The conservator also has eliminated preferred stock dividends, other than dividends on the senior preferred stock. Each series of our preferred stock has no par value, is non-participating, is non-voting and has a liquidation preference equal to the stated value per share. None of our preferred stock is convertible into or exchangeable for any of our other stock or obligations, with the exception of the Convertible Series 2004-1. Shares of the Convertible Series 2004-1 Preferred Stock are convertible at any time, at the option of the holders, into shares of Fannie Mae common stock at a conversion price of $94.31 per share of common stock (equivalent to a conversion rate of 1,060.3329 shares of common stock for each share of Series 2004-1 Preferred Stock). The conversion price is adjustable, as necessary, to maintain the stated conversion rate into common stock. Events which may trigger an adjustment to the conversion price include certain changes in our common stock dividend rate, subdivisions of our outstanding common stock into a greater number of shares, combinations of our outstanding common stock into a smaller number of shares and issuances of any shares by reclassification of our common stock. No such events have occurred. Holders of preferred stock (other than the senior preferred stock) are entitled to receive non-cumulative, quarterly dividends when, and if, declared by our Board of Directors, but have no right to require redemption of any shares of preferred stock. Payment of dividends on preferred stock (other than the senior preferred stock) is not mandatory, but has priority over payment of dividends on common stock, which are also declared by the Board of Directors. If dividends on the preferred stock are not paid or set aside for payment for a given dividend period, dividends may not be paid on our common stock for that period. There were no dividends declared or paid on preferred stock (other than the senior preferred stock) for the years ended December 31, 2015 or 2014 . After a specified period, we have the option to redeem preferred stock (other than the senior preferred stock) at its redemption price plus the dividend (whether or not declared) for the then-current period accrued to, but excluding, the date of redemption. The redemption price is equal to the stated value for all issues of preferred stock except Series O, which has a redemption price of $50 to $52.50 depending on the year of redemption and Convertible Series 2004-1, which has a redemption price of $105,000 per share. Our preferred stock is traded in the over-the-counter market. Senior Preferred Stock and Common Stock Warrant On September 8, 2008, we issued to Treasury one million shares of Variable Liquidation Preference Senior Preferred Stock, Series 2008-2 (“senior preferred stock”), with an aggregate stated value and initial liquidation preference of $1.0 billion . On September 7, 2008, we issued a warrant to purchase common stock to Treasury. The warrant gives Treasury the right to purchase shares of our common stock equal to 79.9% of the total number of shares of common stock outstanding on a fully diluted basis on the date of exercise. The senior preferred stock and the warrant were issued to Treasury as an initial commitment fee in consideration of the commitment from Treasury to provide funds to us under the terms and conditions set forth in the senior preferred stock purchase agreement. We did not receive any cash proceeds as a result of issuing these shares or the warrant. We have assigned a value of $4.5 billion to Treasury’s commitment, which has been recorded as a reduction to additional paid-in-capital and was partially offset by the aggregate fair value of the warrant. There was no impact to the total balance of stockholders’ equity as a result of the issuance. Variable Liquidation Preference Senior Preferred Stock, Series 2008-2 Shares of the senior preferred stock have no par value and have a stated value and initial liquidation preference equal to $1,000 per share. The liquidation preference of the senior preferred stock is subject to adjustment. To the extent dividends payable in any period are not paid in cash, the dividends will accrue and be added to the liquidation preference of the senior preferred stock. In addition, any amounts Treasury pays to us pursuant to its funding commitment provided in the senior preferred stock purchase agreement and any quarterly commitment fee payable under the senior preferred stock purchase agreement that is not paid in cash to or waived by Treasury will be added to the liquidation preference of the senior preferred stock. As of December 31, 2015 , we have received a total of $116.1 billion under Treasury’s funding commitment and the aggregate liquidation preference of the senior preferred stock was $117.1 billion . Treasury, as holder of the senior preferred stock, is entitled to receive, when, as and if declared, out of legally available funds, cumulative quarterly cash dividends. Dividends declared and paid on our senior preferred stock were $10.3 billion , $20.6 billion and $82.5 billion for the years ended December 31, 2015, 2014 and 2013, respectively. Effective January 1, 2013, the amount of dividends payable on the senior preferred stock for a dividend period is determined based on our net worth as of the end of the immediately preceding fiscal quarter. For each dividend period from January 1, 2013 through and including December 31, 2017, the dividend amount will be the amount, if any, by which our net worth as of the end of the immediately preceding fiscal quarter exceeds an applicable capital reserve amount. The capital reserve amount was $2.4 billion and $1.8 billion for dividend periods in 2014 and 2015 , respectively, decreased to $1.2 billion for dividend periods in 2016 , and will continue to be reduced by $600 million each year until it reaches zero on January 1, 2018. For each dividend period beginning in 2018, the dividend amount will be the entire amount of our net worth, if any, as of the end of the immediately preceding fiscal quarter. As a result of these dividend payment provisions and quarterly directives from our conservator, when we have quarterly earnings that result in a net worth greater than the applicable capital reserve amount, we will be required to pay dividends to Treasury in the next quarter; but if our net worth does not exceed the applicable capital reserve amount as of the end of a quarter, then we will not be required to accrue or pay any dividends in the next quarter. The senior preferred stock ranks prior to our common stock and all other outstanding series of our preferred stock, as well as any capital stock we issue in the future, as to both dividends and rights upon liquidation. The senior preferred stock provides that we may not declare or pay dividends on, make distributions with respect to, or redeem, purchase or acquire, or make a liquidation payment with respect to, any common stock or other securities ranking junior to the senior preferred stock unless (1) full cumulative dividends on the outstanding senior preferred stock (including any unpaid dividends added to the liquidation preference) have been declared and paid in cash, and (2) all amounts required to be paid with the net proceeds of any issuance of capital stock for cash (as described in the following paragraph) have been paid in cash. In addition, as described below under “Senior Preferred Stock Purchase Agreement with Treasury—Covenants,” the covenants under the senior preferred stock purchase agreement require that we obtain Treasury’s prior written consent before declaring or paying any dividends or other distributions with respect to our equity securities (other than the senior preferred stock or the warrant) and before redeeming, purchasing, retiring or otherwise acquiring any of our equity securities (other than the senior preferred stock or the warrant). Shares of the senior preferred stock are not convertible. Shares of the senior preferred stock have no general or special voting rights, other than those set forth in the certificate of designation for the senior preferred stock or otherwise required by law. The consent of holders of at least two-thirds of all outstanding shares of senior preferred stock is generally required to amend the terms of the senior preferred stock or to create any class or series of stock that ranks prior to or on parity with the senior preferred stock. We are not permitted to redeem the senior preferred stock prior to the termination of Treasury’s funding commitment under the senior preferred stock purchase agreement. Moreover, we are not permitted to pay down the liquidation preference of the outstanding shares of senior preferred stock except to the extent of (1) accrued and unpaid dividends previously added to the liquidation preference and not previously paid down; and (2) quarterly commitment fees previously added to the liquidation preference and not previously paid down. In addition to these exceptions, if we issue any shares of capital stock for cash while the senior preferred stock is outstanding (which requires Treasury’s approval), we are required to use the net proceeds of the issuance to pay down the liquidation preference of the senior preferred stock; however, the liquidation preference of each share of senior preferred stock may not be paid down below $1,000 per share prior to the termination of Treasury’s funding commitment. Following the termination of Treasury’s funding commitment, we may pay down the liquidation preference of all outstanding shares of senior preferred stock at any time, in whole or in part. Common Stock Warrant The warrant gives Treasury the right to purchase shares of our common stock equal to 79.9% of the total number of shares of our common stock outstanding on a fully diluted basis on the date of exercise. The warrant may be exercised in whole or in part at any time on or before September 7, 2028, by delivery to Fannie Mae of: (a) a notice of exercise; (b) payment of the exercise price of $0.00001 per share; and (c) the warrant. If the market price of one share of common stock is greater than the exercise price, in lieu of exercising the warrant by payment of the exercise price, Treasury may elect to receive shares equal to the value of the warrant (or portion thereof being canceled) pursuant to the formula specified in the warrant. Upon exercise of the warrant, Treasury may assign the right to receive the shares of common stock issuable upon exercise to any other person. If the warrant is exercised, the stated value of the common stock issued will be reclassified as “Common stock” in our consolidated balance sheets. Treasury has not exercised the warrant. Senior Preferred Stock Purchase Agreement with Treasury Funding Commitment Under the senior preferred stock purchase agreement, Treasury made a commitment to provide funding, under certain conditions, to eliminate deficits in our net worth. We have received a total of $116.1 billion from Treasury pursuant to the senior preferred stock purchase agreement as of December 31, 2015 . The aggregate liquidation preference of the senior preferred stock, including the initial aggregate liquidation preference of $1.0 billion , remained at $117.1 billion as of December 31, 2015 . While we had a positive net worth as of December 31, 2015 , in some future periods we could have a net worth deficit and, if so, will be required to obtain additional funding from Treasury pursuant to the senior preferred stock purchase agreement. As of December 31, 2015 , the remaining amount of funding available to us under the agreement was $117.6 billion . If we were to draw additional funds from Treasury under the agreement in a future period, the amount of remaining funding under the agreement would be reduced by the amount of our draw. Dividend payments we make to Treasury do not restore or increase the amount of funding available to us under the agreement. The senior preferred stock purchase agreement provides that the deficiency amount will be calculated differently if we become subject to receivership or other liquidation process. The deficiency amount may be increased above the otherwise applicable amount upon our mutual written agreement with Treasury. In addition, if the Director of FHFA determines that the Director will be mandated by law to appoint a receiver for us unless our capital is increased by receiving funds under the commitment in an amount up to the deficiency amount (subject to the maximum amount that may be funded under the agreement), then FHFA, in its capacity as our conservator, may request that Treasury provide funds to us in such amount. The senior preferred stock purchase agreement also provides that, if we have a deficiency amount as of the date of completion of the liquidation of our assets, we may request funds from Treasury in an amount up to the deficiency amount (subject to the maximum amount that may be funded under the agreement). Any amounts that we draw under the senior preferred stock purchase agreement will be added to the liquidation preference of the senior preferred stock. No additional shares of senior preferred stock are required to be issued under the senior preferred stock purchase agreement. Commitment Fee Pursuant to the August 2012 amendment to the senior preferred stock purchase agreement described in “Note 1, Summary of Significant Accounting Policies,” effective January 1, 2013, the periodic commitment fee under the agreement will not be set, accrue or be payable, as long as the dividend payment provisions described above remain in effect. Covenants The senior preferred stock purchase agreement provides that, until the senior preferred stock is repaid or redeemed in full, we may not, without the prior written consent of Treasury: • Declare or pay any dividend (preferred or otherwise) or make any other distribution with respect to any Fannie Mae equity securities (other than with respect to the senior preferred stock or warrant); • Redeem, purchase, retire or otherwise acquire any Fannie Mae equity securities (other than the senior preferred stock or warrant); • Sell or issue any Fannie Mae equity securities (other than the common stock issuable upon exercise of the warrant or as required by the terms of any binding agreement in effect on the date of the senior preferred stock purchase agreement); • Terminate the conservatorship (other than in connection with a receivership); • Sell, transfer, lease or otherwise dispose of any assets, other than dispositions for fair market value: (a) to a limited life regulated entity (in the context of receivership); (b) of assets and properties in the ordinary course of business, consistent with past practice; (c) of assets and properties having fair market value individually or in aggregate less than $250 million in one transaction or a series of related transactions; (d) in connection with a liquidation of Fannie Mae by a receiver; (e) of cash or cash equivalents for cash or cash equivalents; or (f) to the extent necessary to comply with the covenant described below relating to the reduction of our mortgage assets; • Incur indebtedness that would result in our aggregate indebtedness exceeding $563.6 billion through December 31, 2015 . For every year thereafter, our debt cap will equal 120% of the amount of mortgage assets we are allowed to own under the senior preferred stock purchase agreement on December 31 of the immediately preceding calendar year; • Issue any subordinated debt; • Enter into a corporate reorganization, recapitalization, merger, acquisition or similar event; or • Engage in transactions with affiliates unless the transaction is (a) pursuant to the senior preferred stock purchase agreement, the senior preferred stock or the warrant, (b) upon arm’s-length terms or (c) a transaction undertaken in the ordinary course or pursuant to a contractual obligation or customary employment arrangement in existence on the date of the senior preferred stock purchase agreement. The agreement, as amended, also provides that we may not own mortgage assets in excess of $399.2 billion as of December 31, 2015 . On each December 31 thereafter, we are required to reduce our mortgage assets to 85% of the maximum allowable amount that we were permitted to own as of December 31 of the immediately preceding calendar year, until the amount of our mortgage assets reaches $250 billion . In 2014, FHFA requested that we revise our portfolio plan to cap the portfolio each year at 90% of the annual limit under our senior preferred stock purchase agreement with Treasury. FHFA’s request noted that we may seek FHFA permission to increase this cap up to 95% of the annual limit under our senior preferred stock purchase agreement with Treasury upon written request and with a documented basis for exception, such as changed market conditions. Under the agreement, the effect of changes in generally accepted accounting principles that occurred subsequent to the date of the agreement and that require us to recognize additional mortgage assets in our consolidated balance sheets are not considered for purposes of evaluating our compliance with the limitation on the amount of mortgage assets we may own. In addition, the definition of indebtedness in the agreement was revised to clarify that it also does not give effect to any change that may be made in respect of the FASB guidance on accounting for transfers of financial assets or any similar accounting guidance. In addition, the agreement provides that we may not enter into any new compensation arrangements with, or increase amounts or benefits payable under existing compensation arrangements of, any named executive officer or other executive officer (each as defined by SEC rules) without the consent of the Director of FHFA, in consultation with the Secretary of the Treasury. As of December 31, 2015 , we were in compliance with the senior preferred stock purchase agreement covenants. We are required to provide an annual risk management plan to Treasury no later than December 15 of each year we remain in conservatorship, beginning in 2012. Each annual risk management plan is required to set out our strategy for reducing our risk profile and to describe the actions we will take to reduce the financial and operational risks associated with each of our business segments. Each plan must include an assessment of our performance against the planned actions described in the prior year’s plan. We submitted our most recent annual risk management plan to Treasury in December 2015 . Termination Provisions The senior preferred stock purchase agreement provides that Treasury’s funding commitment will terminate under any the following circumstances: (1) the completion of our liquidation and fulfillment of Treasury’s obligations under its funding commitment at that time, (2) the payment in full of, or reasonable provision for, all of our liabilities (whether or not contingent, including mortgage guaranty obligations), or (3) the funding by Treasury of the maximum amount under the agreement. In addition, Treasury may terminate its funding commitment and declare the senior preferred stock purchase agreement null and void if a court vacates, modifies, amends, conditions, enjoins, stays or otherwise affects the appointment of the conservator or otherwise curtails the conservator’s powers. Treasury may not terminate its funding commitment solely by reason of our being in conservatorship, receivership or other insolvency proceeding, or due to our financial condition or any adverse change in our financial condition. Waivers and Amendments The senior preferred stock purchase agreement provides that most provisions of the agreement may be waived or amended by mutual written agreement of the parties. No waiver or amendment of the agreement, however, may decrease Treasury’s aggregate funding commitment or add conditions to Treasury’s funding commitment if the waiver or amendment would adversely affect in any material respect the holders of our debt securities or guaranteed Fannie Mae MBS. Third-party Enforcement Rights If we default on payments with respect to our debt securities or guaranteed Fannie Mae MBS and Treasury fails to perform its obligations under its funding commitment, and if we and/or the conservator are not diligently pursuing remedies in respect of that failure, the holders of these debt securities or Fannie Mae MBS may file a claim for relief in the United States Court of Federal Claims. The relief, if granted, would require Treasury to fund to us the lesser of (1) the amount necessary to cure the payment defaults on our debt and Fannie Mae MBS and (2) the lesser of (a) the deficiency amount and (b) the maximum amount available under the agreement less the aggregate amount of funding previously provided under the commitment. Any payment that Treasury makes under those circumstances would be treated for all purposes as a draw under the senior preferred stock purchase agreement that would increase the liquidation preference of the senior preferred stock. Accumulated Other Comprehensive Income The following table displays our accumulated other comprehensive income. As of December 31, 2015 2014 2013 (Dollars in millions) Net unrealized gains on AFS securities for which we have not recorded OTTI, net of tax $ 455 $ 592 $ 365 Net unrealized gains on AFS securities for which we have recorded OTTI, net of tax 903 1,529 1,262 Prior service credit (cost) and actuarial gains (losses), net of amortization, and other, net of tax 49 (388 ) (424 ) Accumulated other comprehensive income $ 1,407 $ 1,733 $ 1,203 The table below displays changes in accumulated other comprehensive income, net of tax. For the Year Ended December 31, 2015 2014 AFS Securities (1) Other (2) Total AFS Securities (1) Other Total (Dollars in millions) Beginning balance $ 2,121 $ (388 ) $ 1,733 $ 1,627 $ (424 ) $ 1,203 Other comprehensive income before reclassifications (280 ) 17 (263 ) 722 37 759 Amounts reclassified from other comprehensive income (483 ) 420 (63 ) (228 ) (1 ) (229 ) Net other comprehensive income (763 ) 437 (326 ) 494 36 530 Ending balance $ 1,358 $ 49 $ 1,407 $ 2,121 $ (388 ) $ 1,733 __________ (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 consolidated statements of operations and comprehensive income. (2) The amounts reclassified from AOCI includes a reclassification adjustment related to the termination of the defined benefit pension plans, which is recorded in “Administrative expenses” and “Benefit (provision) for federal income taxes,” in our consolidated statements of operations and comprehensive income.

Regulatory Capital Requirements

Regulatory Capital Requirements	12 Months Ended
	Dec. 31, 2015
Regulatory Capital Requirements [Abstract]
Regulatory Capital Requirements	Regulatory Capital Requirements FHFA stated that, during conservatorship, our existing statutory and FHFA-directed regulatory capital requirements will not be binding and FHFA will not issue quarterly capital classifications. We submit capital reports to FHFA and FHFA monitors our capital levels. FHFA has stated that it does not intend to report our critical capital, risk-based capital or subordinated debt levels during the conservatorship. Our regulatory capital classification measures are determined based on guidance from FHFA, in which FHFA (1) directed us, for loans backing Fannie Mae MBS held by third parties, to continue reporting our minimum capital requirements based on 0.45% of the unpaid principal balance and critical capital based on 0.25% of the unpaid principal balance, regardless of whether these loans have been consolidated pursuant to accounting rules, and (2) issued a regulatory interpretation stating that our minimum capital requirements are not automatically affected by the consolidation accounting guidance. Additionally, our regulatory capital classification measures exclude the funds provided to us by Treasury pursuant to the senior preferred stock purchase agreement, as the senior preferred stock does not qualify as core capital due to its cumulative dividend provisions. Pursuant to the GSE Act, if the Director of FHFA makes a written determination that our total assets are less than our total obligations (a net worth deficit) for a period of 60 days , FHFA is mandated by law to appoint a receiver for Fannie Mae. Treasury’s funding commitment under the senior preferred stock purchase agreement is intended to ensure that we avoid a net worth deficit, in order to avoid this mandatory trigger of receivership. In order to avoid a net worth deficit, our conservator may request funds on our behalf from Treasury under the senior preferred stock purchase agreement. FHFA has directed us, during the time we are under conservatorship, to focus on managing to a positive net worth. We had a positive net worth of $4.1 billion and $3.7 billion as of December 31, 2015 and 2014 , respectively. The following table displays our regulatory capital classification measures. As of December 31, 2015 2014 (Dollars in millions) Core capital (1) $ (114,526 ) $ (115,202 ) Statutory minimum capital requirement (2) 25,144 27,044 Deficit of core capital over statutory minimum capital requirement $ (139,670 ) $ (142,246 ) __________ (1) The sum of (a) the stated value of our outstanding common stock (common stock less treasury stock); (b) the stated value of our outstanding non-cumulative perpetual preferred stock; (c) our paid-in capital; and (d) our retained earnings (accumulated deficit). Core capital does not include: (a) accumulated other comprehensive income or (b) senior preferred stock. (2) Generally, the sum of (a) 2.50% of on-balance sheet assets, except those underlying Fannie Mae MBS held by third parties; (b) 0.45% of the unpaid principal balance of outstanding Fannie Mae MBS held by third parties; and (c) up to 0.45% of other off-balance sheet obligations, which may be adjusted by the Director of FHFA under certain circumstances. Our critical capital requirement is generally equal to the sum of: (1) 1.25% of on-balance sheet assets, except those underlying Fannie Mae MBS held by third parties; (2) 0.25% of the unpaid principal balance of outstanding Fannie Mae MBS held by third parties; and (3) 0.25% of other off-balance sheet obligations, which may be adjusted by the Director of FHFA under certain circumstances. As of December 31, 2015 and 2014 , we had a minimum capital deficiency of $139.7 billion and $142.2 billion , respectively. Under the terms of the senior preferred stock purchase agreement with Treasury, beginning January 1, 2013, we are required to pay Treasury each quarter dividends when, as and if declared, equal to the excess of our net worth as of the end of the immediately preceding fiscal quarter over an applicable capital reserve amount. As a result, in periods in which we have net worth, our minimum capital deficiency will decline to the extent of our net worth but the deficiency will increase in the subsequent period as we pay Treasury the corresponding senior preferred stock dividend. See “ Note 13, Equity ” for more information on capital and the terms of our senior preferred stock purchase agreement with Treasury. Set forth below are additional restrictions related to our capital requirements. Restrictions on Capital Distributions and Dividends Restrictions Under GSE Act. Under the GSE Act, FHFA has the authority to prohibit capital distributions, including payment of dividends, if we fail to meet our capital requirements. If FHFA classifies us as significantly undercapitalized, we must obtain the approval of the Director of FHFA for any dividend payment. Under the GSE Act, we are not permitted to make a capital distribution if, after making the distribution, we would be undercapitalized. The Director of FHFA, however, may permit us to repurchase shares if the repurchase is made in connection with the issuance of additional shares or obligations in at least an equivalent amount and will reduce our financial obligations or otherwise improve our financial condition. Restrictions Relating to Conservatorship. Our conservator announced on September 7, 2008 that we would not pay any dividends on the common stock or on any series of preferred stock, other than the senior preferred stock. In addition, FHFA’s regulations relating to conservatorship and receivership operations prohibit us from paying any dividends while in conservatorship unless authorized by the Director of FHFA. The Director of FHFA directs us to make dividend payments on the senior preferred stock on a quarterly basis. Restrictions Under Senior Preferred Stock Purchase Agreement. The senior preferred stock purchase agreement prohibits us from declaring or paying any dividends on Fannie Mae equity securities (other than the senior preferred stock) without the prior written consent of Treasury. In addition, in 2012 the terms of the senior preferred stock purchase agreement and the senior preferred stock were amended to ultimately require the payment of our entire net worth to Treasury. As a result, our net income is not available to common stockholders. For more information on the terms of the senior preferred stock purchase agreement and senior preferred stock, see “ Note 13, Equity .” Additional Restrictions Relating to Preferred Stock. Payment of dividends on our common stock is also subject to the prior payment of dividends on our preferred stock and our senior preferred stock. Payment of dividends on all outstanding preferred stock, other than the senior preferred stock, is also subject to the prior payment of dividends on the senior preferred stock.

Concentrations of Credit Risk

Concentrations of Credit Risk	12 Months Ended
	Dec. 31, 2015
Risks and Uncertainties [Abstract]
Concentrations of Credit Risk	Concentrations of Credit Risk Concentrations of credit risk arise when a number of customers and counterparties engage in similar activities or have similar economic characteristics that make them susceptible to similar changes in industry conditions, which could affect their ability to meet their contractual obligations. Based on our assessment of business conditions that could impact our financial results, we have determined that concentrations of credit risk exist among single-family and multifamily borrowers (including geographic concentrations and loans with certain higher-risk characteristics), mortgage sellers and servicers, mortgage insurers, financial guarantors, multifamily lenders with risk sharing, derivative counterparties and parties associated with our off-balance sheet transactions. Concentrations for each of these groups are discussed below. Single-Family Loan Borrowers Regional economic conditions may affect a borrower’s ability to repay his or her mortgage loan and the property value underlying the loan. Geographic concentrations increase the exposure of our portfolio to changes in credit risk. Single-family borrowers are primarily affected by home prices and interest rates. The geographic dispersion of our single-family business has been consistently diversified over the years ended December 31, 2015 and 2014, with our largest exposures in the Western region of the United States, which represented approximately 28% of our single-family conventional guaranty book of business as of December 31, 2015 and 2014. Except for California, where approximately 20% of the gross unpaid principal balance of our single-family conventional mortgage loans held or securitized in Fannie Mae MBS as of December 31, 2015 and 2014, were located, no other significant concentrations existed in any state. To manage credit risk and comply with legal requirements, we typically require primary mortgage insurance or other credit enhancements if the current LTV ratio ( i.e. , the ratio of the unpaid principal balance of a loan to the current value of the property that serves as collateral) of a single-family conventional mortgage loan is greater than 80% when the loan is delivered to us. Multifamily Loan Borrowers Numerous factors affect a multifamily borrower’s ability to repay the loan and the value of the property underlying the loan. The most significant factors affecting credit risk are rental income, capitalization rates for the mortgaged property, and general economic conditions. The average unpaid principal balance for multifamily loans is significantly larger than for single-family borrowers and, therefore, individual defaults for multifamily borrowers can result in more significant losses. However, we continually monitor the performance and risk characteristics of our multifamily loans, underlying properties and borrowers on an ongoing basis. Our multifamily geographic concentrations have been consistently diversified over the years ended December 31, 2015 and 2014, with our largest exposure in the Western region of the United States, which represented 30% and 31% of our multifamily guaranty book of business as of December 31, 2015 and 2014, respectively. Except for California, Texas and New York, no significant concentrations existed in any states as of December 31, 2015. As of December 31, 2015 , 23% , 11% and 10% of the gross unpaid principal balance of multifamily mortgage loans held by us or securitized in Fannie Mae MBS were located in California, Texas and New York, respectively. As of December 31, 2014 , 23% , 11% and 11% of the gross unpaid principal balance of multifamily mortgage loans held by us or securitized in Fannie Mae MBS were located in California, Texas and New York, respectively. No significant concentrations existed in any other states as of December 31, 2014. As part of our multifamily risk management activities, we perform detailed loan reviews that evaluate borrower and geographic concentrations, lender qualifications, counterparty risk, property performance and contract compliance. We generally require mortgage servicers to submit periodic property operating information and condition reviews, allowing us to monitor the performance of individual loans. We use this information to evaluate the credit quality of our portfolio, identify potential problem loans and initiate appropriate loss mitigation activities. The following table displays the regional geographic concentration of single-family and multifamily loans in our guaranty book of business. Geographic Concentration (1) Percentage of Single-Family Conventional Guaranty Book of Business (2) Percentage of Multifamily Guaranty Book of Business (3) As of December 31, As of December 31, 2015 2014 2015 2014 Midwest 15 % 15 % 9 % 9 % Northeast 19 19 17 18 Southeast 22 22 23 22 Southwest 16 16 21 20 West 28 28 30 31 Total 100 % 100 % 100 % 100 % __________ (1) Midwest consists of IL, IN, IA, MI, MN, NE, ND, OH, SD, WI; Northeast consists of CT, DE, ME, MA, NH, NJ, NY, PA, PR, RI, VT, VI; Southeast consists of AL, DC, FL, GA, KY, MD, MS, NC, SC, TN, VA, WV; Southwest consists of AZ, AR, CO, KS, LA, MO, NM, OK, TX, UT; West consists of AK, CA, GU, HI, ID, MT, NV, OR, WA and WY. (2) Consists of the portion of our single-family conventional guaranty book of business for which we have detailed loan level information, which constituted over 99% of our total single-family conventional guaranty book of business as of December 31, 2015 and 2014. (3) Consists of the portion of our multifamily guaranty book of business for which we have detailed loan level information, which constituted 99% of our total multifamily guaranty book of business as of December 31, 2015 and 2014. 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 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 DSCR below 1.0 and high original LTV ratios. We stratify multifamily loans into different internal risk categories based on the credit risk inherent in each individual loan. For single-family and multifamily loans, we use this information, in conjunction with housing market and economic conditions, to structure our pricing and our eligibility and underwriting criteria to reflect the current risk of loans with these higher-risk characteristics, and in some cases we decide to significantly reduce our participation in riskier loan product categories. Management also uses this data together with other credit risk measures to identify key trends that guide the development of our loss mitigation strategies. The following tables display the delinquency status and serious delinquency rates for specified loan categories of our single-family conventional and total multifamily guaranty book of business. As of December 31, 2015 (1) 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) 1.27 % 0.37 % 1.59 % 1.27 % 0.38 % 1.99 % Percentage of single-family conventional loans (4) 1.46 0.41 1.55 1.47 0.43 1.89 As of December 31, 2015 (1) 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 % 10.76 % 5 % 10.98 % Geographical distribution: California 20 0.58 20 0.70 Florida 6 2.86 6 4.42 New Jersey 4 4.87 4 5.78 New York 5 3.55 5 4.17 All other states 65 1.34 65 1.57 Product distribution: Alt-A 4 6.53 4 7.77 Vintages: 2005 2 5.67 3 6.18 2006 3 8.49 3 9.61 2007 3 9.73 4 10.79 2008 2 5.84 2 6.27 All other vintages 90 0.77 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 December 31, 2015 and 2014 . (2) Consists of single-family conventional loans that were 90 days or more past due or in the foreclosure process as of December 31, 2015 and 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 December 31, 2015 (1)(2) 2014 (1)(2) 30 Days Delinquent Seriously Delinquent (3) 30 Days Delinquent Seriously Delinquent (3) Percentage of multifamily guaranty book of business 0.03 % 0.07 % 0.04 % 0.05 % As of December 31, 2015 (1) 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 % 0.40 % 3 % 0.31 % Less than or equal to 80% 97 0.06 97 0.04 Current DSCR less than 1.0 (5) 2 1.51 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 December 31, 2015 and 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. Alt-A Loans and Securities We own and guarantee Alt-A mortgage loans and mortgage-related securities. An Alt-A mortgage loan generally refers to a mortgage loan that has been underwritten with reduced or alternative documentation than that required for a full documentation mortgage loan but may also include other alternative product features. As a result, Alt-A mortgage loans generally have a higher risk of default than non-Alt-A mortgage loans. In reporting our Alt-A exposure, we have classified mortgage loans as Alt-A if and only if the lenders that deliver the mortgage loans to us have classified the loans as Alt-A, based on documentation or other product features. We have classified private-label mortgage-related securities held in our investment portfolio as Alt-A if the securities were labeled as such when issued. We apply our classification criteria in order to discuss our exposure to Alt-A loans. However, there is no universally accepted definition of Alt-A loans. Our single-family conventional guaranty book of business includes loans with some features that are similar to Alt-A loans that we have not classified as Alt-A because they do not meet our classification criteria. We reduce our risk associated with some of these loans through credit enhancements, as described below under “Mortgage Insurers.” We do not rely solely on our classifications of loans as Alt-A to evaluate the credit risk exposure relating to these loans in our single-family conventional guaranty book of business. The Alt-A mortgage loans and Fannie Mae MBS backed by Alt-A loans of $103.1 billion in unpaid principal balance represented 4% of our single-family mortgage credit book of business as of December 31, 2015 , compared with $117.6 billion in unpaid principal balance which represented 4% of our single-family mortgage credit book of business as of December 31, 2014 . Other Concentrations Mortgage Sellers and Servicers. Mortgage servicers collect mortgage and escrow payments from borrowers, pay taxes and insurance costs from escrow accounts, monitor and report delinquencies, and perform other required activities on our behalf. Our mortgage sellers and servicers may also be obligated to repurchase loans or foreclosed properties, reimburse us for losses or provide other remedies under certain circumstances, such as if it is determined that the mortgage loan did not meet our underwriting or eligibility requirements, if certain loan representations and warranties are violated or if mortgage insurers rescind coverage. However, under our revised representation and warranty framework, we no longer require repurchase for loans that have breaches of certain selling representations and warranties if they have met specified criteria for relief. Our business with mortgage servicers is concentrated. Our five largest single-family mortgage servicers, including their affiliates, serviced approximately 44% of our single-family guaranty book of business as of December 31, 2015 , compared with approximately 46% as of December 31, 2014 . Our ten largest multifamily mortgage servicers, including their affiliates, serviced approximately 70% of our multifamily guaranty book of business as of December 31, 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 $117.9 billion and $109.6 billion on the single-family mortgage loans in our guaranty book of business as of December 31, 2015 and 2014, respectively, which represented 4% of our single-family guaranty book of business as of December 31, 2015 and 2014. Our primary mortgage insurance coverage risk in force was $117.2 billion and $108.7 billion as of December 31, 2015 and 2014, respectively. Our pool mortgage insurance coverage risk in force was $736 million and $852 million as of December 31, 2015 and 2014, respectively. Our top four mortgage insurance companies provided 79% of our mortgage insurance coverage risk in force as of December 31, 2015 and 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 $10.1 billion , or 9% , of our risk in force mortgage insurance coverage of our single-family guaranty book of business as of December 31, 2015 . PMI and Triad have been paying only a portion of policyholder claims and deferring the remaining portion. PMI is currently paying 70% of claims under its mortgage insurance policies in cash and is deferring the remaining 30% , and Triad is currently paying 75% of claims in cash and deferring the remaining 25% . It is uncertain whether PMI or Triad will be permitted in the future to pay any remaining deferred policyholder claims and/or increase or decrease the amount of cash they pay on claims. RMIC is no longer deferring payments on policyholder claims and has paid us amounts of its previously outstanding deferred payment obligations to bring payment on our claims to 100% ; however, RMIC remains in run-off and under the supervisory control of its state regulator. We were not paid interest to compensate us for the amount of time RMIC’s deferred payment obligations were outstanding. 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 December 31, 2015 and 2014, the amount by which our estimated benefit from mortgage insurance reduced our total loss reserves was $2.3 billion and $4.1 billion , respectively. We had outstanding receivables of $1.2 billion recorded in “Other assets” in our consolidated balance sheets as of December 31, 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, $241 million as of December 31, 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 $770 million as of December 31, 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 December 31, 2015 and 2014. Financial Guarantors. We are the beneficiary of non-governmental financial guarantees on non-agency securities held in our retained mortgage portfolio and on non-agency securities that have been resecuritized to include a Fannie Mae guaranty and sold to third parties. The total unpaid principal balance of guaranteed non-agency securities in our retained mortgage portfolio was $3.2 billion and $4.6 billion as of December 31, 2015 and 2014, respectively. Of the total unpaid principal balance, approximately 68% was mortgage revenue bonds as of December 31, 2015 , compared with 70% as of December 31, 2014 , and the remaining amount was composed of Alt-A private-label securities, subprime private-label securities and other mortgage-related securities. If a financial guarantor fails to meet its obligations to us with respect to the securities for which we have obtained financial guarantees, it could reduce the fair value of our mortgage-related securities and result in financial losses to us, which could have an adverse effect on our earnings, liquidity, financial condition and net worth. With the exception of Ambac Assurance Corporation (“Ambac”), which is operating under a deferred payment obligation, none of our remaining non-governmental financial guarantor counterparties has failed to repay us for claims under guaranty contracts. Effective July 21, 2014, the terms of Ambac’s order regarding its deferred payment arrangements changed to increase its cash payments on policyholder claims from 25% to 45% and to provide for payment of sufficient amounts of its outstanding deferred payment obligations to bring payment on those claims to 45% . We are expecting full cash payment from only half of our non-governmental financial guarantor counterparties, and we are uncertain of the level of payments we will ultimately receive from the remaining counterparties. Ambac provided coverage on $1.7 billion , or 52% , of our total non-governmental guarantees as of December 31, 2015 . When assessing our securities for impairment, we consider the benefit of non-governmental financial guarantees from those guarantors that we determine are creditworthy, although we continue to seek collection of any amounts due to us from all counterparties. We are also the beneficiary of financial guarantees included in securities issued by Freddie Mac, the federal government and its agencies that totaled $16.7 billion as of December 31, 2015 and $19.2 billion as of December 31, 2014 . Multifamily Lenders with Risk Sharing. We enter into risk sharing agreements with lenders pursuant to which the lenders agree to bear all or some portion of the credit losses on the covered loans. Our maximum potential loss recovery from lenders under these risk sharing agreements on both Delegated Underwriting and Servicing (“DUS”) and non-DUS multifamily loans was $46.2 billion as of December 31, 2015 , compared with $41.7 billion as of December 31, 2014 . As of December 31, 2015 , 40% of our maximum potential loss recovery on multifamily loans was from four DUS lenders, compared with 39% as of December 31, 2014 . Parties Associated with Our Off-Balance Sheet Transactions. We enter into financial instrument transactions that create off-balance sheet credit risk in the normal course of our business. These transactions are designed to meet the financial needs of our customers, and manage our credit, market or liquidity risks. We have entered into guarantees for which we have not recognized a guaranty obligation in our consolidated balance sheets relating to periods prior to 2003, the effective date of accounting guidance related to guaranty accounting. Our maximum potential exposure under these guarantees was $5.6 billion as of December 31, 2015 and $6.5 billion as of December 31, 2014 . If we were required to make payments under these guarantees, we would pursue recovery through our right to the collateral backing the underlying loans, available credit enhancements and recourse with third parties that provided a maximum coverage of $2.4 billion as of December 31, 2015 and $2.7 billion as of December 31, 2014 . Derivatives Counterparties. For information on credit risk associated with our derivative transactions and repurchase agreements see “ Note 9, Derivative Instruments ” and “ Note 16, Netting Arrangements .”

Netting Arrangements

Netting Arrangements	12 Months Ended
	Dec. 31, 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 consolidated balance sheets. As of December 31, 2015 Net Amount Presented in the Consolidated Balance Sheets Amounts Not Offset in the Consolidated Balance Sheets Gross Amount Gross Amount Offset (1) Financial Instruments (2) Collateral (3) Net Amount (Dollars in millions) Assets: OTC risk management derivatives $ 4,042 $ (4,021 ) $ 21 $ — $ (18 ) $ 3 Cleared risk management derivatives 708 (3 ) 705 — — 705 Mortgage commitment derivatives 140 — 140 (119 ) (3 ) 18 Total derivative assets 4,890 (4,024 ) 866 (4 ) (119 ) (21 ) 726 Securities purchased under agreements to resell or similar arrangements (5) 37,950 — 37,950 — (37,950 ) — Total assets $ 42,840 $ (4,024 ) $ 38,816 $ (119 ) $ (37,971 ) $ 726 Liabilities: OTC risk management derivatives $ (6,118 ) $ 5,861 $ (257 ) $ — $ — $ (257 ) Cleared risk management derivatives (2,796 ) 2,789 (7 ) — — (7 ) Mortgage commitment derivatives (158 ) — (158 ) 119 (1 ) (40 ) Total derivative liabilities (9,072 ) 8,650 (422 ) (4 ) 119 (1 ) (304 ) Securities sold under agreements to repurchase or similar arrangements (62 ) — (62 ) — 62 — Total liabilities $ (9,134 ) $ 8,650 $ (484 ) $ 119 $ 61 $ (304 ) As of December 31, 2014 Net Amount Presented in the Consolidated Balance Sheets Amounts Not Offset in the 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 consolidated balance sheets. (3) Represents collateral posted or received that has neither been recognized nor offset in our consolidated balance sheets. Does not include collateral held in excess of our exposure. The fair value of non-cash collateral accepted for OTC risk management derivatives was $37 million and $51 million as of December 31, 2015 and 2014, respectively. The fair value of non-cash collateral accepted for securities purchased under agreements to resell or similar arrangements was $38.0 billion and $47.6 billion , of which $36.2 billion and $41.9 billion could be sold or repledged as of December 31, 2015 and 2014, respectively. None of the underlying collateral was sold or repledged as of December 31, 2015 or 2014. The fair value of non-cash collateral we pledged for securities sold under agreements to repurchase was $62 million and $50 million as of December 31, 2015 and 2014, which the counterparty was permitted to sell or repledge. The fair value of non-cash collateral we pledged for cleared risk management derivatives was $135 million as of December 31, 2015 , which the counterparty was permitted to sell or repledge. (4) Excludes derivative assets of $28 million as of December 31, 2015 and 2014, and derivative liabilities of $2 million and $1 million recognized in our consolidated balance sheets as of December 31, 2015 and 2014, respectively, that are not subject to enforceable master netting arrangements. (5) Includes $10.6 billion and $16.6 billion of securities purchased under agreements to resell classified as “Cash and cash equivalents” in our consolidated balance sheets as of December 31, 2015 and 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 consolidated balance sheets. We determine our rights to offset the assets and liabilities presented above with the same counterparty, including collateral posted or received, based on the contractual arrangements entered into with our individual counterparties and various rules and regulations that would govern the insolvency of a derivative counterparty. The following is a description, under various agreements, of the nature of those rights and their effect or potential effect on our financial position. The terms of the majority of our contracts for OTC risk management derivatives are governed under master agreements of the International Swaps and Derivatives Association Inc. (“ISDA”). These agreements provide that all transactions entered into under the agreement with the counterparty constitute a single contractual relationship. An event of default by the counterparty allows the early termination of all outstanding transactions under the same ISDA agreement and we may offset all outstanding amounts related to the terminated transactions including collateral posted or received. The terms of our contracts for cleared derivatives are governed under the rules of the clearing organization and the agreement between us and the clearing member of that clearing organization. In the event of a clearing organization default, all open positions at the clearing organization are closed and a net position (on a clearing member by clearing member basis) is calculated. Unless otherwise transferred, in the event of a clearing member default, all open positions cleared through that clearing member are closed and a net position is calculated. The terms of our contracts for mortgage commitment derivatives are primarily governed by the Fannie Mae Single-Family Selling Guide (“Guide”), for Fannie Mae-approved lenders, or Master Securities Forward Transaction Agreements (“MSFTA”), for counterparties that are not Fannie Mae-approved lenders. In the event of default by the counterparty, both the Guide and the MSFTA allow us to terminate all outstanding transactions under the applicable agreement and offset all outstanding amounts related to the terminated transactions including collateral posted or received. Under the Guide, upon a lender event of default, we generally may offset any amounts owed to a lender against any amounts a lender may owe us under any other existing agreement, regardless of whether or not such other agreements are in default or payments are immediately due. The terms of our contracts for securities purchased under agreements to resell and securities sold under agreements to repurchase are governed by Master Repurchase Agreements, which are based on the guidelines prescribed by the Securities Industry and Financial Markets Association. Master Repurchase Agreements provide that all transactions under the agreement constitute a single contractual relationship. An event of default by the counterparty allows the early termination of all outstanding transactions under the same agreement and we may offset all outstanding amounts related to the terminated transactions including collateral posted or received. We also have securities purchased under agreements to resell which we transact through the Fixed Income Clearing Corporation (“FICC”). Under the rules of the FICC, all agreements for securities purchased under agreements to resell that are submitted to the FICC for clearing become transactions with the FICC that are subject to FICC clearing rules. In the event of a FICC default, all open positions at the FICC are closed and a net position is calculated.

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 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 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 December 31, 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 $ — $ 4,813 $ — $ — $ 4,813 Freddie Mac — 1,314 — — 1,314 Ginnie Mae — 426 — — 426 Alt-A private-label securities — 131 305 — 436 Subprime private-label securities — — 644 — 644 CMBS — 2,341 — — 2,341 Mortgage revenue bonds — — 449 — 449 Non-mortgage-related securities: U.S. Treasury securities 29,485 — — — 29,485 Total trading securities 29,485 9,025 1,398 — 39,908 Available-for-sale securities: Mortgage-related securities: Fannie Mae — 4,221 — — 4,221 Freddie Mac — 4,295 4 — 4,299 Ginnie Mae — 391 — — 391 Alt-A private-label securities — 1,637 1,041 — 2,678 Subprime private-label securities — — 3,281 — 3,281 CMBS — 1,255 — — 1,255 Mortgage revenue bonds — — 2,701 — 2,701 Other — — 1,404 — 1,404 Total available-for-sale securities — 11,799 8,431 — 20,230 Mortgage loans — 12,598 1,477 — 14,075 Other assets: Risk management derivatives: Swaps — 4,541 156 — 4,697 Swaptions — 53 — — 53 Other — — 28 — 28 Netting adjustment — — — (4,024 ) (4,024 ) Mortgage commitment derivatives — 135 5 — 140 Total other assets — 4,729 189 (4,024 ) 894 Total assets at fair value $ 29,485 $ 38,151 $ 11,495 $ (4,024 ) $ 75,107 Fair Value Measurements as of December 31, 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 $ — $ 10,764 $ 369 $ — $ 11,133 Total of Fannie Mae — 10,764 369 — 11,133 Of consolidated trusts — 23,113 496 — 23,609 Total long-term debt — 33,877 865 — 34,742 Other liabilities: Risk management derivatives: Swaps — 8,697 20 — 8,717 Swaptions — 197 — — 197 Other — — 2 — 2 Netting adjustment — — — (8,650 ) (8,650 ) Mortgage commitment derivatives — 148 10 — 158 Total other liabilities — 9,042 32 (8,650 ) 424 Total liabilities at fair value $ — $ 42,919 $ 897 $ (8,650 ) $ 35,166 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 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 Year Ended December 31, 2015 Total Gains (Losses) (Realized/Unrealized) Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of December 31, 2015 (5)(6) Balance, December 31, 2014 Included in Net Income Included in Total Other Comprehensive Income (Loss) (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 (4) Transfers into Level 3 (4) Balance, December 31, 2015 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 305 $ (27 ) $ — $ — $ (2 ) $ — $ — $ (278 ) $ 2 $ — $ — Alt-A private-label securities 597 36 — — (267 ) — (45 ) (44 ) 28 305 15 Subprime private-label securities 1,307 36 — — (611 ) — (88 ) — — 644 10 Mortgage revenue bonds 722 (41 ) — — (220 ) — (12 ) — — 449 (33 ) Other 99 4 — — (100 ) — (3 ) — — — — Total trading securities $ 3,030 $ 8 (6)(7) $ — $ — $ (1,200 ) $ — $ (148 ) $ (322 ) $ 30 $ 1,398 $ (8 ) Available-for-sale securities: Mortgage-related: Fannie Mae $ — $ — $ — $ 421 $ (425 ) $ — $ (8 ) $ — $ 12 $ — $ — Freddie Mac 6 — — — — — (1 ) (2 ) 1 4 — Alt-A private-label securities 3,140 215 (173 ) — (1,504 ) — (436 ) (538 ) 337 1,041 — Subprime private-label securities 5,240 599 (382 ) — (1,575 ) — (601 ) — — 3,281 — Mortgage revenue bonds 4,023 51 (104 ) — (410 ) — (859 ) — — 2,701 — Other 2,671 (26 ) (2 ) — (1,012 ) — (227 ) — — 1,404 — Total available-for-sale securities $ 15,080 $ 839 (7)(8) $ (661 ) $ 421 $ (4,926 ) $ — $ (2,132 ) $ (540 ) $ 350 $ 8,431 $ — Mortgage loans $ 1,833 $ 57 (6)(7) $ — $ 5 $ — $ — $ (350 ) $ (377 ) $ 309 $ 1,477 $ (20 ) Net derivatives 45 (55 ) (6) — — — (4 ) 169 (7 ) 9 157 (2 ) Long-term debt: Of Fannie Mae: Senior floating $ (363 ) $ (6 ) $ — $ — $ — $ — $ — $ — $ — $ (369 ) $ (6 ) Of consolidated trusts (527 ) (9 ) — — — (66 ) 57 228 (179 ) (496 ) 17 Total long-term debt $ (890 ) $ (15 ) (6) $ — $ — $ — $ (66 ) $ 57 $ 228 $ (179 ) $ (865 ) $ 11 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Year Ended December 31, 2014 Total Gains (Losses) (Realized/Unrealized) Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of December 31, 2014 (5)(6) Balance, December 31, 2013 Included in Net Income Included in Total Other Comprehensive Income (Loss) (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 (4) Transfers into Level 3 (4) Balance, December 31, 2014 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 42 $ (27 ) $ — $ 6 $ — $ — $ (2 ) $ (39 ) $ 325 $ 305 $ (18 ) Freddie Mac 2 — — — — — — (2 ) — — — Alt-A private-label securities 618 88 — — (58 ) — (81 ) (226 ) 256 597 97 Subprime private-label securities 1,448 270 — — (241 ) — (170 ) — — 1,307 234 Mortgage revenue bonds 565 168 — — — — (11 ) — — 722 160 Other 99 13 — — — — (13 ) — — 99 13 Total trading securities $ 2,774 $ 512 (6)(7) $ — $ 6 $ (299 ) $ — $ (277 ) $ (267 ) $ 581 $ 3,030 $ 486 Available-for-sale securities: Mortgage-related: Fannie Mae $ 7 $ — $ — $ — $ — $ — $ (1 ) $ (8 ) $ 2 $ — $ — Freddie Mac 8 — — — — — (1 ) (2 ) 1 6 — Alt-A private-label securities 3,791 172 (26 ) — (393 ) — (471 ) (1,738 ) 1,805 3,140 — Subprime private-label securities 7,068 447 301 — (1,730 ) — (846 ) — — 5,240 — Mortgage revenue bonds 5,253 (32 ) 554 — (70 ) — (1,682 ) — — 4,023 — Other 2,885 19 103 — — — (336 ) — — 2,671 — Total available-for-sale securities $ 19,012 $ 606 (7)(8) $ 932 $ — $ (2,193 ) $ — $ (3,337 ) $ (1,748 ) $ 1,808 $ 15,080 $ — Mortgage loans $ 2,704 $ 260 (6)(7) $ — $ 36 $ — $ — $ (344 ) $ (1,113 ) $ 290 $ 1,833 $ 53 Net derivatives (40 ) 103 (6) — — — — (21 ) (2 ) 5 45 77 Long-term debt: Of Fannie Mae: Senior floating $ (955 ) $ (142 ) $ — $ — $ — $ (750 ) $ 19 $ 1,465 $ — $ (363 ) $ (97 ) Of consolidated trusts (518 ) (53 ) — — — (1 ) 62 111 (128 ) (527 ) (49 ) Total long-term debt $ (1,473 ) $ (195 ) (6) $ — $ — $ — $ (751 ) $ 81 $ 1,576 $ (128 ) $ (890 ) $ (146 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Year Ended December 31, 2013 Total Gains (Losses) (Realized/Unrealized) Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of December 31, 2013 (5)(6) Balance, December 31, 2012 Included in Net Income Included in Total Other Comprehensive Income (Loss) (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 (4) Transfers into Level 3 (4) Balance, December 31, 2013 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 68 $ (9 ) $ — $ — $ — $ — $ (17 ) $ — $ — $ 42 $ (9 ) Freddie Mac 2 — — — — — — — — 2 — Ginnie Mae 1 — — — — — (1 ) (3 ) 3 — — Alt-A private-label securities 104 256 — — — — (115 ) (435 ) 808 618 223 Subprime private-label securities 1,319 328 — — (50 ) — (149 ) — — 1,448 322 Mortgage revenue bonds 675 (101 ) — — — — (9 ) — — 565 (101 ) Other 117 (5 ) — — — — (13 ) — — 99 (5 ) Total trading securities $ 2,286 $ 469 (6)(7) $ — $ — $ (50 ) $ — $ (304 ) $ (438 ) $ 811 $ 2,774 $ 430 Available-for-sale securities: Mortgage-related: Fannie Mae $ 29 $ — $ (1 ) $ — $ — $ — $ (7 ) $ (14 ) $ — $ 7 $ — Freddie Mac 10 — (1 ) — — — (2 ) (1 ) 2 8 — Ginnie Mae — — — — — — — (1 ) 1 — — Alt-A private-label securities 6,564 144 464 — (2,664 ) — (1,040 ) (3,357 ) 3,680 3,791 — Subprime private-label securities 7,447 120 1,527 359 (1,317 ) — (1,068 ) — — 7,068 — Mortgage revenue bonds 7,837 25 (449 ) — (35 ) — (2,125 ) — — 5,253 — Other 3,147 13 125 — — — (400 ) — — 2,885 — Total available-for-sale securities $ 25,034 $ 302 (7)(8) $ 1,665 $ 359 $ (4,016 ) $ — $ (4,642 ) $ (3,373 ) $ 3,683 $ 19,012 $ — Mortgage loans $ 2,634 $ 282 (6)(7) $ — $ 346 $ (393 ) $ — $ (459 ) $ (352 ) $ 646 $ 2,704 $ 50 Net derivatives 14 (165 ) (6) — — — — 97 16 (2 ) (40 ) (51 ) Long-term debt: Of Fannie Mae: Senior floating $ (400 ) $ 76 $ — $ — $ — $ (674 ) $ 43 $ — $ — $ (955 ) $ 76 Of consolidated trusts (1,128 ) (250 ) — — — (21 ) 537 434 (90 ) (518 ) (80 ) Total long-term debt $ (1,528 ) $ (174 ) (6) $ — $ — $ — $ (695 ) $ 580 $ 434 $ (90 ) $ (1,473 ) $ (4 ) __________ (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 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 gains (losses), net” in our consolidated statements of operations and comprehensive income. (7) Gains (losses) are included in “Net interest income” in our consolidated statements of operations and comprehensive income. (8) Gains (losses) are included in “Investment gains, net” in our 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 December 31, 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) $ 305 Consensus Default Rate (%) 1.3 - 4.9 3.6 Prepayment Speed (%) 2.2 - 4.5 3.7 Severity (%) 20.5 - 95.0 69.3 Spreads (bps) 219.0 - 263.3 253.1 Total Alt-A private-label securities 305 Subprime private-label securities (2) 526 Consensus Default Rate (%) 4.2 - 8.4 5.9 Prepayment Speed (%) 0.4 - 5.3 3.3 Severity (%) 55.9 - 95.0 73.7 Spreads (bps) 285.0 285.0 73 Consensus 45 Other Total subprime private-label securities 644 Mortgage revenue bonds 437 Discounted Cash Flow Spreads (bps) 1.5 - 376.2 298.9 12 Other Total mortgage revenue bonds 449 Total trading securities $ 1,398 Fair Value Measurements as of December 31, 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) 671 Consensus Default Rate (%) 0.5 - 40.7 3.4 Prepayment Speed (%) 1.7 - 72.6 13.5 Severity (%) 1.4 - 95.0 58.5 Spreads (bps) 225.6 - 280.4 260.0 201 Consensus 169 Discounted Cash Flow Default Rate (%) 4.0 - 5.0 4.8 Prepayment Speed (%) 4.0 - 7.5 6.4 Severity (%) 50.0 - 64.0 59.2 Spreads (bps) 260.0 - 369.4 296.5 Total Alt-A private-label securities 1,041 Subprime private-label securities (2) 343 Single Vendor Default Rate (%) 2.5 - 7.5 4.8 Prepayment Speed (%) 1.9 - 5.7 3.3 Severity (%) 67.6 - 85.7 72.7 Spreads (bps) 285.0 - 340.0 299.6 1,848 Consensus Default Rate (%) 0.5 - 11.3 5.9 Prepayment Speed (%) 0.5 - 11.2 3.8 Severity (%) 20.0 - 95.0 79.0 Spreads (bps) 255.0 - 285.0 283.3 945 Consensus 145 Other Total subprime private-label securities 3,281 Mortgage revenue bonds 991 Single Vendor Spreads (bps) (33.1 ) - 386.8 37.9 1,462 Discounted Cash Flow Spreads (bps) (15.8 ) - 379.1 283.8 248 Other Total mortgage revenue bonds 2,701 Other 683 Consensus Default Rate (%) 0.5 - 4.6 3.4 Prepayment Speed (%) 2.5 - 15.5 4.7 Severity (%) 6.6 - 95.0 65.7 Spreads (bps) 200.0 - 454.4 315.6 520 Discounted Cash Flow Default Rate (%) 0.0 - 1.8 0.0 Prepayment Speed (%) 0.0 - 0.5 0.0 Severity (%) 95.0 95.0 Spreads (bps) 260.0 - 350.0 323.6 201 Other Total other 1,404 Total available-for-sale securities $ 8,431 Fair Value Measurements as of December 31, 2015 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Mortgage loans: Single-family $ 127 Build-Up Default Rate (%) 0.0 - 99.2 34.8 Prepayment Speed (%) 3.0 - 100.0 10.4 Severity (%) 0.0 - 100.0 39.9 632 Build-Up 234 Consensus Default Rate (%) 0.5 - 5.0 3.7 Prepayment Speed (%) 2.5 - 26.0 6.4 Severity (%) 20.0 - 89.1 69.0 Spreads (bps) 255.0 - 277.6 264.6 274 Consensus 54 Other Total single-family 1,321 Multifamily 156 Build-Up Spreads (bps) 70.0 - 327.2 158.8 Total mortgage loans $ 1,477 Net derivatives $ 17 Internal Model 136 Dealer Mark 4 Other Total net derivatives $ 157 Long-term debt: Of Fannie Mae: Senior floating $ (369 ) Discounted Cash Flow Of consolidated trusts (4) (181 ) Consensus Default Rate (%) 0.5 - 3.8 3.4 Prepayment Speed (%) 2.5 - 26.0 5.6 Severity (%) 20.0 - 80.6 67.8 Spreads (bps) 255.0 - 270.0 265.8 (149 ) Consensus (166 ) Other Total of consolidated trusts (496 ) Total long-term debt $ (865 ) 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, Freddie Mac and Ginnie Mae 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 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 December 31, 2015 or December 31, 2014. We held $17 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 December 31, 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 as of December 31, Valuation Techniques 2015 2014 (Dollars in millions) Nonrecurring fair value measurements: Mortgage loans held for sale, at lower of cost or fair value Consensus $ 3,651 $ 110 Single Vendor 336 — Other 4 — Total mortgage loans held for sale, at lower of cost or fair value 3,991 110 Single-family mortgage loans held for investment, at amortized cost Internal Model 6,379 16,654 Other — 60 Total single-family mortgage loans held for investment, at amortized cost 6,379 16,714 Multifamily mortgage loans held for investment, at amortized cost Broker Price Opinions 82 45 Asset Manager Estimate 236 580 Other 5 — Total multifamily mortgage loans held for investment, at amortized cost 323 625 Acquired property, net: Single-family Accepted Offers 541 864 Appraisals 1,117 1,509 Walk Forwards 433 1,173 Internal Model 986 1,045 Other 134 191 Total single-family 3,211 4,782 Multifamily Broker Price Opinions — 127 Other — 13 Total multifamily — 140 Other assets Other 30 45 Total nonrecurring assets at fair value $ 13,934 $ 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 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 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 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, guaranty obligation (“GO”) and master servicing arrangement. We use observable market values of Fannie Mae MBS with similar characteristics, either on a pool or loan level, determined primarily from third party pricing services, quoted market prices in active markets for similar securities, and other observable market data as a base value. We set the GO equal to the estimated fair value we would receive if we were to issue our guaranty to an unrelated party in a stand-alone arm’s length transaction at the measurement date. We estimate the fair value of the GO using our internal valuation models, which calculate the present value of expected cash flows based on management’s best estimate of certain key assumptions such as current mark-to-market LTV ratios, future house prices, default rates, severity rates and required rate of return. We also estimate the fair value of the GO using our current guaranty pricing and adjust that pricing, as appropriate, for the seasoning of the collateral when such transactions reflect credit characteristics of loans held in our portfolio. As a result, the fair value of our mortgage loans will change when the pricing for our credit guaranty changes in the GSE securitization market. Our performing loans are generally classified as Level 2 of the valuation hierarchy to the extent that significant inputs are observable. To the extent that unobservable inputs are significant, the loans are classified as Level 3 of the valuation hierarchy. Consensus: The fair value of single-family nonperforming loans and TDRs on accrual status represents an estimate of the prices we would receive if we were to sell these loans in the whole-loan market. These nonperforming loans and TDRs on accrual status are either two or more months delinquent, in an open modification period, or in a closed modification state (both performing and nonperforming in accordance with the loan’s modified terms). Key factors that influence the price of these loans include collateral value,

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 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, accruals and disclosures. We have substantial and valid defenses to the claims in the proceedings described below and intend to defend these matters vigorously. However, legal actions and proceedings of all types are subject to many uncertain factors that generally cannot be predicted with assurance. Accordingly, the outcome of any given matter and the amount or range of potential loss at particular points in time is frequently difficult to ascertain. Uncertainties can include how fact finders will evaluate documentary evidence and the credibility and effectiveness of witness testimony, and how courts will apply the law. Disposition valuations are also subject to the uncertainty of how opposing parties and their counsel may view the evidence and applicable law. We establish an accrual for matters when a loss is probable and we can reasonably estimate the amount of such loss. For legal actions or proceedings where there is only a reasonable possibility that a loss may be incurred, or where we are not currently able to estimate the reasonably possible loss or range of loss, we do not establish an accrual. We are often unable to estimate the possible losses or ranges of losses, particularly for proceedings that are in their early stages of development, where plaintiffs seek indeterminate or unspecified damages, where there may be novel or unsettled legal questions relevant to the proceedings, or where settlement negotiations have not occurred or progressed. Given the uncertainties involved in any action or proceeding, regardless of whether we have established an accrual, the ultimate resolution of certain of these matters may be material to our operating results for a particular period, depending on, among other factors, the size of the loss or liability imposed and the level of our net income or loss for that period. In addition to the matters specifically described below, we are involved in a number of legal and regulatory proceedings that arise in the ordinary course of business that we do not expect will have a material impact on our business or financial condition. We have also advanced fees and expenses of certain current and former officers and directors in connection with various legal proceedings pursuant to our bylaws and indemnification agreements. Senior Preferred Stock Purchase Agreements Litigation A number of putative class action lawsuits were filed in the U.S. District Court for the District of Columbia against us, FHFA as our conservator, Treasury and Freddie Mac from July through September 2013 by shareholders of Fannie Mae and/or Freddie Mac challenging the August 2012 amendment to each company’s senior preferred stock purchase agreement with Treasury. These lawsuits were consolidated and, on December 3, 2013, plaintiffs (preferred and common shareholders of Fannie Mae and/or Freddie Mac) filed a consolidated class action complaint in the U.S. District Court for the District of Columbia against us, FHFA as our conservator, Treasury and Freddie Mac (“ In re Fannie Mae/Freddie Mac Senior Preferred Stock Purchase Agreement Class Action Litigations ”). The preferred shareholder plaintiffs allege that the net worth sweep dividend provisions of the senior preferred stock that were implemented pursuant to the August 2012 amendments to the senior preferred stock purchase agreements nullified certain of the shareholders’ rights, particularly the right to receive dividends. The common shareholder plaintiffs allege that the August 2012 amendments constituted a taking of their property by requiring that all future profits of Fannie Mae and Freddie Mac be paid to Treasury. Plaintiffs allege claims for breach of contract and breach of the implied covenant of good faith and fair dealing against us, FHFA and Freddie Mac, a takings claim against FHFA and Treasury, and a breach of fiduciary duty claim derivatively on our and Freddie Mac’s behalf against FHFA and Treasury. Plaintiffs seek to represent several classes of preferred and/or common shareholders of Fannie Mae and/or Freddie Mac who held stock as of the public announcement of the August 2012 amendments. Plaintiffs seek unspecified damages, equitable and injunctive relief, and costs and expenses, including attorneys’ fees. A non-class action suit, Arrowood Indemnity Company v. Fannie Mae , was filed in the U.S. District Court for the District of Columbia on September 20, 2013 by preferred shareholders against us, FHFA as our conservator, the Director of FHFA (in his official capacity), Treasury, the Secretary of the Treasury (in his official capacity) and Freddie Mac. Plaintiffs bring claims for breach of contract and breach of the implied covenant of good faith and fair dealing against us, FHFA and Freddie Mac, and claims for violation of the Administrative Procedure Act against the FHFA and Treasury defendants, alleging that the net worth sweep 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. Unconditional Purchase and Lease Commitments We have unconditional commitments related to the purchase of loans and mortgage-related securities. These include both on- and off-balance sheet commitments. A portion of these have been recorded as derivatives in our consolidated balance sheets. We lease certain premises and equipment under agreements that expire at various dates through 2033. Some of these leases provide for payment by the lessee of property taxes, insurance premiums, cost of maintenance and other costs. Rental expenses for operating leases were $47 million , $43 million and $41 million for the years ended December 31, 2015, 2014 and 2013, respectively. The following table summarizes by remaining maturity, non-cancelable future commitments related to loan and mortgage purchases, operating leases and other agreements. As of December 31, 2015 Loans and Mortgage-Related Securities (1) Operating Leases (2) Other (3) (Dollars in millions) 2016 $ 58,715 $ 44 $ 59 2017 — 46 15 2018 — 32 11 2019 — 49 5 2020 — 53 4 Thereafter — 718 — Total $ 58,715 $ 942 $ 94 __________ (1) Primarily includes $58.5 billion that has been accounted for as mortgage commitment derivatives. (2) Includes amounts related to office buildings and equipment leases. (3) Includes purchase commitments for certain telecommunications services, computer software and services, and other agreements and commitments.

Selected Quarterly Financial In

Selected Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Information (Unaudited)	Selected Quarterly Financial Information (Unaudited) The consolidated statements of operations for the quarterly periods in 2015 and 2014 are unaudited and in the opinion of management include all adjustments, consisting of normal recurring adjustments, necessary for a fair presentation of our consolidated statements of operations. Certain prior period amounts have been reclassified to conform to the current period presentation. The operating results for the interim periods are not necessarily indicative of the operating results to be expected for a full year or for other interim periods. For the 2015 Quarter Ended March 31 June 30 September 30 December 31 (Dollars and shares in millions, except per share amounts) Interest income: Trading securities $ 115 $ 116 $ 99 $ 114 Available-for-sale securities 376 294 261 225 Mortgage loans 27,044 26,682 26,980 26,993 Other 33 34 37 39 Total interest income 27,568 27,126 27,377 27,371 Interest expense: Short-term debt 29 33 37 47 Long-term debt 22,472 21,416 21,752 22,247 Total interest expense 22,501 21,449 21,789 22,294 Net interest income 5,067 5,677 5,588 5,077 Benefit (provision) for credit losses 533 (1,033 ) 1,550 (255 ) Net interest income after benefit (provision) for credit losses 5,600 4,644 7,138 4,822 Investment gains, net 342 514 299 181 Fair value gains (losses), net (1,919 ) 2,606 (2,589 ) 135 Fee and other income 308 556 259 225 Non-interest income (loss) (1,269 ) 3,676 (2,031 ) 541 Administrative expenses: Salaries and employee benefits 351 331 317 320 Professional services 271 251 219 243 Occupancy expenses 43 43 43 53 Other administrative expenses 58 64 373 70 Total administrative expenses 723 689 952 686 Foreclosed property expense 473 182 497 477 TCCA fees 382 397 413 429 Other expenses (income), net (5 ) 202 215 201 Total expenses 1,573 1,470 2,077 1,793 Income before federal income taxes 2,758 6,850 3,030 3,570 Provision for federal income taxes (870 ) (2,210 ) (1,070 ) (1,103 ) Net income 1,888 4,640 1,960 2,467 Less: Net income attributable to noncontrolling interest — — — (1 ) Net income attributable to Fannie Mae 1,888 4,640 1,960 2,466 Dividends distributed or available for distribution to senior preferred stockholder (1,796 ) (4,359 ) (2,202 ) (2,859 ) Net income (loss) attributable to common stockholders (Note 11) $ 92 $ 281 $ (242 ) $ (393 ) Earnings (loss) per share: Basic and Diluted $ 0.02 $ 0.05 $ (0.04 ) $ (0.07 ) Weighted-average common shares outstanding: Basic 5,762 5,762 5,762 5,762 Diluted 5,893 5,893 5,762 5,762 For the 2014 Quarter Ended March 31 June 30 September 30 December 31 (Dollars and shares in millions, except per share amounts) Interest income: Trading securities $ 127 $ 143 $ 151 $ 132 Available-for-sale securities 440 414 395 373 Mortgage loans 28,588 28,165 27,779 27,588 Other 24 24 29 33 Total interest income 29,179 28,746 28,354 28,126 Interest expense: Short-term debt 20 21 26 27 Long-term debt 24,421 23,821 23,144 22,957 Total interest expense 24,441 23,842 23,170 22,984 Net interest income 4,738 4,904 5,184 5,142 Benefit for credit losses 774 1,639 1,085 466 Net interest income after benefit for credit losses 5,512 6,543 6,269 5,608 Investment gains, net 95 483 171 187 Fair value losses, net (1,190 ) (934 ) (207 ) (2,502 ) Fee and other income 4,355 383 826 323 Non-interest income (loss) 3,260 (68 ) 790 (1,992 ) Administrative expenses: Salaries and employee benefits 325 319 337 340 Professional services 242 275 263 296 Occupancy expenses 50 47 47 59 Other administrative expenses 55 56 59 7 Total administrative expenses 672 697 706 702 Foreclosed property expense (income) (262 ) (214 ) 249 369 TCCA fees 322 335 351 367 Other expenses, net 131 238 61 48 Total expenses 863 1,056 1,367 1,486 Income before federal income taxes 7,909 5,419 5,692 2,130 Provision for federal income taxes (2,584 ) (1,752 ) (1,787 ) (818 ) Net income 5,325 3,667 3,905 1,312 Less: Net income attributable to noncontrolling interest — (1 ) — — Net income attributable to Fannie Mae 5,325 3,666 3,905 1,312 Dividends distributed or available for distribution to senior preferred stockholder (5,692 ) (3,712 ) (3,999 ) (1,920 ) Net loss attributable to common stockholders (Note 11) $ (367 ) $ (46 ) $ (94 ) $ (608 ) Loss per share: Basic and Diluted $ (0.06 ) $ (0.01 ) $ (0.02 ) $ (0.11 ) Weighted-average common shares outstanding: Basic and Diluted 5,762 5,762 5,762 5,762

Summary of Significant Accoun28

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Segment Reporting, Policy [Policy Text Block]	We operate under three business segments: Single-Family Credit Guaranty (“Single-Family”), Multifamily and Capital Markets. Our Single-Family segment generates revenue primarily from the guaranty fees on the mortgage loans underlying guaranteed single-family Fannie Mae mortgage-backed securities (“Fannie Mae MBS”). Our Multifamily segment generates revenue from a variety of sources, including guaranty fees on the mortgage loans underlying multifamily Fannie Mae MBS, transaction fees associated with the multifamily business and bond credit enhancement fees. Our Capital Markets segment invests in mortgage loans, mortgage-related securities and other investments, and generates income primarily from the difference, or spread, between the yield on the mortgage assets we own and the interest we pay on the debt we issue in the global capital markets to fund the purchases of these mortgage assets. 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 structure, the sum of the results for our three business segments does not equal our consolidated results of operations as we separate the activity related to our consolidated trusts from the results generated by our three segments. In addition, we apply accounting methods for segment reporting purposes that differ from our consolidated results. Therefore, we reconcile the sum of the results for our three business segments to our consolidated results of operations.
Basis of Presentation [Policy Text Block]	Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with GAAP. To conform to our current period presentation, we have reclassified certain amounts reported in our prior periods’ consolidated financial statements. 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 is 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 is 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 benefit for credit losses and did not retrospectively adjust our 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 is 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 redesignation 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 aligns the unit of account that is used for both the initial and subsequent lower of cost or fair value measurements on our HFS portfolio. Additionally, by performing the lower of cost or fair value calculation at the loan level, the adjustment is calculated on a more disaggregated basis. As this change in accounting policy was 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 our consolidated financial statements for this change.
Single-Family Guaranty Fees 10 Basis Points Increase due to the Temporary Payroll Tax Cut Continuation Act of 2011 Provision [Policy Text Block]	Effective April 1, 2012, the guaranty fee on all single-family residential mortgages delivered to Fannie Mae on or after that date was increased by 10 basis points. FHFA and Treasury have advised us to remit this fee increase to Treasury with respect to all loans acquired by us on or after April 1, 2012 and before January 1, 2022, and to continue to remit these amounts to Treasury on and after January 1, 2022 with respect to loans we acquired before this date until those loans are paid off or otherwise liquidated. The resulting fee revenue and expense are recorded in “Mortgage loans interest income” and “TCCA fees,” respectively, in our consolidated statements of operations and comprehensive income.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates Preparing 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 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.
Consolidations, Policy [Policy Text Block]	Principles of Consolidation Our consolidated financial statements include our accounts as well as the accounts of the other entities in which we have a controlling financial interest. All intercompany balances and transactions have been eliminated. The typical condition for a controlling financial interest is ownership of a majority of the voting interests of an entity. A controlling financial interest may also exist in entities through arrangements that do not involve voting interests, such as a VIE. We have interests in various entities that are considered to be 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.
Consolidation, Variable Interest Entity, Policy [Policy Text Block]	VIE Assessment We have interests in various entities that are considered VIEs. A VIE is an entity (1) that has total equity at risk that is not sufficient to finance its activities without additional subordinated financial support from other entities, (2) where the group of equity holders does not have the power to direct the activities of the entity that most significantly impact the entity’s economic performance, or the obligation to absorb the entity’s expected losses or the right to receive the entity’s expected residual returns, or both, or (3) where the voting rights of some investors are not proportional to their obligations to absorb the expected losses of the entity, their rights to receive the expected residual returns of the entity, or both, and substantially all of the entity’s activities either involve or are conducted on behalf of an investor that has disproportionately few voting rights. We determine if an entity is a VIE by performing a qualitative analysis, which requires certain subjective decisions including, but not limited to, the design of the entity, the variability that the entity was designed to create and pass along to its interest holders, the rights of the parties and the purpose of the arrangement. If we cannot conclude after a qualitative analysis whether an entity is a VIE, we perform a quantitative analysis. The primary types of VIE entities with which we are involved are securitization trusts guaranteed by us via lender swap and portfolio securitization transactions, limited partnership investments in low-income housing tax credit (“LIHTC”) and other housing partnerships, as well as mortgage and asset-backed trusts that were not created by us. Primary Beneficiary Determination If an entity is a VIE, we consider whether our variable interest in that entity causes us to be the primary beneficiary. We are deemed to be the primary beneficiary of a VIE when we have both (1) the power to direct the activities of the VIE that most significantly impact the entity’s economic performance, and (2) exposure to benefits and/or losses that could potentially be significant to the entity. The primary beneficiary of the VIE is required to consolidate and account for the assets, liabilities, and noncontrolling interests of the VIE in its consolidated financial statements. The assessment of which party has the power to direct the activities of the VIE may require significant management judgment when (1) more than one party has power or (2) more than one party is involved in the design of the VIE but no party has the power to direct the ongoing activities that could be significant. We continually assess whether we are the primary beneficiary of the VIEs with which we are involved and therefore may consolidate or deconsolidate a VIE through the duration of our involvement. Examples of certain events that may change whether or not we consolidate the VIE include a change in the design of the entity or a change in our ownership in the entity such that we no longer hold substantially all of the certificates issued by a multi-class resecuritization trust. Measurement of Consolidated Assets and Liabilities When we are the transferor of assets into a VIE that we consolidate at the time of the transfer, we continue to recognize the assets and liabilities of the VIE at the amounts that they would have been recognized if we had not transferred them, and no gain or loss is recognized. For all other VIEs that we consolidate (that is, those for which we are not the transferor), we recognize the assets and liabilities of the VIE in our consolidated financial statements at fair value, and we recognize a gain or loss for the difference between (1) the fair value of the consideration paid, fair value of noncontrolling interests and the reported amount of any previously held interests, and (2) the net amount of the fair value of the assets and liabilities consolidated. However, for the securitization trusts established under our lender swap program, no gain or loss is recognized if the trust is consolidated at formation as there is no difference in the respective fair value of (1) and (2) above. We record gains or losses that are associated with the consolidation of VIEs as “Investment gains, net” in our consolidated statements of operations and comprehensive income . If we cease to be deemed the primary beneficiary of a VIE, we deconsolidate the VIE. We use fair value to measure the initial cost basis for any retained interests that are recorded upon the deconsolidation of a VIE. Any difference between the fair value and the previous carrying amount of our investment in the VIE is recorded as “Investment gains, net” in our consolidated statements of operations and comprehensive income. Purchase/Sale of Fannie Mae Securities We actively purchase and may subsequently sell guaranteed MBS that have been issued through our lender swap and portfolio securitization transaction programs. The accounting for the purchase and sale of our guaranteed MBS issued by the trusts differs based on the characteristics of the securitization trusts and whether the trusts are consolidated. Single-Class Securitization Trusts We create single-class securitization trusts to issue single-class Fannie Mae MBS that evidence an undivided interest in the mortgage loans held in the trust. Investors in single-class Fannie Mae MBS receive principal and interest payments in proportion to their percentage ownership of the MBS issuance. We guarantee to each single-class securitization trust that we will supplement amounts received by the single-class securitization trust as required to permit timely payments of principal and interest on the related Fannie Mae MBS. This guaranty exposes us to credit losses on the loans underlying Fannie Mae MBS. Single-class securitization trusts are used for both our lender swap and portfolio securitization transaction programs. A lender swap transaction occurs when a mortgage lender delivers a pool of single-family mortgage loans to us, which we immediately deposit into an MBS trust. The MBS are then issued to the lender in exchange for the mortgage loans. A portfolio securitization transaction occurs when we purchase mortgage loans from third-party sellers for cash and later deposit these loans into an MBS trust. The securities issued through a portfolio securitization are then sold to investors for cash. We consolidate single-class securitization trusts that are issued under these programs when our role as guarantor and master servicer provides us with the power to direct matters, such as the servicing of the 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 (e.g., when the loan collateral is subject to a Federal Housing Administration guaranty and related Servicing Guide). When we purchase single-class Fannie Mae MBS issued from a consolidated trust, we account for the transaction as an extinguishment of the related debt in our consolidated financial statements. We record a gain or loss on the extinguishment of such debt to the extent that the purchase price of the MBS does not equal the carrying value of the related consolidated debt reported in our consolidated balance sheets (including unamortized premiums, discounts or the other cost basis adjustments) at the time of purchase. We account for the sale of an MBS from Fannie Mae’s portfolio that was issued from a consolidated trust as the issuance of debt in our consolidated financial statements. We amortize the related premiums, discounts and other cost basis adjustments into income over time. To determine the order in which consolidated debt is extinguished, we have elected to use a daily convention in the application of the last-issued first-extinguished method. Under this method, we record the net daily change in each MBS holding as either the issuance of debt if there has been an increase in the position that is held by third parties, or the extinguishment of the most recently issued related debt if there has been a decrease in the position held by third parties. The impact of this method is that we record the net daily activity for an MBS as if it were a single buy or sell trade, which results in a change in our beginning debt balance if the total unpaid principal balance purchased does not match the total unpaid principal balance sold. If a single-class securitization trust is not consolidated, we account for the purchase and subsequent sale of such securities as the transfer of an investment security in accordance with the accounting guidance for transfers of financial assets. Single-Class Resecuritization Trusts Single-class resecuritization trusts (Fannie Megas®) are created by depositing Fannie Mae MBS into a new securitization trust for the purpose of aggregating multiple MBS into a single larger security. The cash flows from the new security represent an aggregation of the cash flows from the underlying MBS. We guarantee to each single-class resecuritization trust that we will supplement amounts received by the trust as required to permit timely payments of principal and interest on the related Fannie Mae securities. However, we assume no additional credit risk in such a resecuritization transaction, because the underlying assets are MBS for which we have already provided a guaranty. Additionally, our involvement with these trusts does not provide any incremental rights or power that would enable Fannie Mae to direct any activities of the trusts. As a result, we have concluded that we are not the primary beneficiaries of, and therefore do not consolidate, our single-class resecuritization trusts. As our single-class resecuritization securities pass through all of the cash flows of the underlying MBS directly to the holders of the securities, they are deemed to be substantially the same as the underlying MBS. Therefore, we account for purchases of our single-class resecuritization securities as an extinguishment of the underlying MBS debt and the sale of these securities as an issuance of the underlying MBS debt. Multi-Class Resecuritization Trusts Multi-class resecuritization trusts are trusts we create to issue multi-class Fannie Mae securities, including Real Estate Mortgage Investment Conduit (“REMIC”) and interest-only and principal-only strip securities, in which the cash flows of the underlying mortgage assets are divided, creating several classes of securities, each of which represents a beneficial ownership interest in a separate portion of cash flows. We guarantee to each multi-class resecuritization trust that we will supplement amounts received by the trusts as required to permit timely payments of principal and interest, as applicable, on the related Fannie Mae securities. However, we assume no additional credit risk in such a resecuritization transaction because the underlying assets are Fannie Mae MBS for which we have already provided a guaranty. Although we may be exposed to prepayment risk via our ownership of the securities issued by these trusts, we do not have the ability via our involvement with a multi-class resecuritization trust to impact the economic risk to which we are exposed. Therefore, we do not consolidate such a multi-class resecuritization trust until we hold a substantial portion of the outstanding beneficial interests that have been issued by the trust and are therefore considered the primary beneficiary of the trust. In contrast to our single-class resecuritization trust, the cash flows from the underlying MBS are divided between the debt securities issued by the multi-class resecuritization trust, and therefore, the debt issued by a multi-class resecuritization trust is not substantially the same as the consolidated MBS debt. As a result, if a multi-class resecuritization trust is not consolidated, we account for the purchase and sale of such securities as the transfer of an investment security in accordance with the accounting guidance for the transfers of financial assets rather than the issuance or extinguishment of the related multi-class debt. However, if a multi-class resecuritization trust is consolidated, we account for the purchase of the securities issued by consolidated multi-class resecuritization trusts as an extinguishment of the debt issued by these trusts and the subsequent sale of such securities as the issuance of multi-class debt. When we do not consolidate a multi-class resecuritization trust, we recognize in our consolidated financial statements both our investment in the trust and the mortgage loans of the Fannie Mae MBS trusts that we consolidate that underlie the multi-class resecuritization trust. Additionally, we recognize the unsecured corporate debt issued to third parties to fund the purchase of our investments in the multi-class resecuritization trusts and the debt issued to third parties of the MBS trusts we consolidate that underlie the multi-class resecuritization trusts. This results in the recognition of interest income from investments in multi-class resecuritization trusts and interest expense from the unsecured debt issued to third parties to fund the purchase of the investments in multi-class resecuritization trusts, as well as interest income from the mortgage loans and interest expense from the debt issued to third parties from the MBS trusts we consolidate that underlie the multi-class resecuritization trusts.
Transfers and Servicing of Financial Assets, Policy [Policy Text Block]	Transfers of Financial Assets We evaluate a transfer of financial assets to determine whether the transfer qualifies as a sale. If the transfer does not meet the criteria for sale treatment, the transferred assets remain in our consolidated balance sheets and we record a liability to the extent of any proceeds received in connection with such a transfer. Transfers of financial assets for which we surrender control of the transferred assets are recorded as sales. When a transfer that qualifies as a sale is completed, we derecognize all assets transferred and recognize all assets obtained and liabilities incurred at fair value. The difference between the carrying basis of the assets transferred and the fair value of the proceeds from the sale is recorded as a component of “Investment gains, net” in our consolidated statements of operations and comprehensive income. Retained interests are primarily derived from transfers associated with our portfolio securitizations in the form of Fannie Mae MBS, REMIC certificates, guaranty assets and master servicing assets (“MSAs”). We separately describe the subsequent accounting, as well as how we determine fair value, for our retained interests in the Fannie Mae MBS included in the “Investments in Securities” section of this note. We enter into repurchase agreements that involve contemporaneous trades to purchase and sell securities. These transactions are accounted for as secured financings since the transferor has not relinquished control over the transferred assets. These transactions are reported as securities purchased under agreements to resell and securities sold under agreements to repurchase in our consolidated balance sheets except for securities purchased under agreements to resell on an overnight basis, which are included in cash and cash equivalents in our consolidated balance sheets. 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.
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and Cash Equivalents and Statements of Cash Flows Short-term investments that have a maturity at the date of acquisition of three months or less and are readily convertible to known amounts of cash are generally considered cash equivalents. We also include securities purchased under agreements to resell on an overnight basis in cash and cash equivalents in our consolidated balance sheets. We may pledge as collateral certain short-term investments classified as cash equivalents. In the presentation of our consolidated statements of cash flows, we present cash flows from derivatives that do not contain financing elements and mortgage loans held for sale at acquisition as operating activities. We present cash flows from federal funds sold and securities purchased under agreements to resell or similar arrangements as investing activities and cash flows from federal funds purchased and securities sold under agreements to repurchase as financing activities. We classify cash flows from trading securities based on their nature and purpose. Effective January 1, 2014, we classify all cash flows from trading securities (U.S. Treasury securities and mortgage-related securities purchased subsequent to December 31, 2013) as operating activities as we do not intend to hold the securities for investment. We classify cash flows from mortgage-related trading securities purchased prior to January 1, 2014 that we intend to hold for investment as investing activities. For consolidated trusts, we classify cash flows related to mortgage loans held by our consolidated trusts as either investing activities (for principal repayments) or operating activities (for interest received from borrowers included as a component of our net income). Cash flows related to debt securities issued by consolidated trusts are classified as either financing activities (for repayments of principal to certificateholders) or operating activities (for interest payments to certificateholders included as a component of our net income). We distinguish between the payments and proceeds related to the debt of Fannie Mae and the debt of consolidated trusts, as applicable. We present our non-cash activities in the consolidated statements of cash flows at the associated unpaid principal balance.
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]	Restricted Cash We and our servicers advance payments on delinquent loans to consolidated Fannie Mae MBS trusts. We recognize the cash advanced as “Restricted cash” in our consolidated balance sheets to the extent such amounts are due to, but have not yet been remitted to, the MBS certificateholders. In addition, when we or our servicers collect and hold cash that is due to certain Fannie Mae MBS trusts in advance of our requirement to remit these amounts to the trusts, we recognize the collected cash amounts as “Restricted cash.” We also recognize “Restricted cash” as a result of restrictions related to certain consolidated partnership funds as well as for certain collateral arrangements for which we do not have the right to use the cash.
Marketable Securities, Policy [Policy Text Block]	Investments in Securities Securities Classified as Available-for-Sale or Trading We classify and account for our securities as either available-for-sale (“AFS”) or trading. We measure AFS securities at fair value in our consolidated balance sheets, with unrealized gains and losses included in “Accumulated other comprehensive income” (“AOCI”), net of income taxes. We recognize realized gains and losses on AFS securities when securities are sold. We calculate the gains and losses using the specific identification method and record them in “Investment gains, net” in our consolidated statements of operations and comprehensive income. We measure trading securities at fair value in our consolidated balance sheets with unrealized and realized gains and losses included as a component of “Fair value gains (losses), net” in our consolidated statements of operations and comprehensive income. We include interest and dividends on securities in our consolidated statements of operations and comprehensive income. Interest income includes the amortization of cost basis adjustments, including premiums and discounts, recognized as a yield adjustment using the interest method over the contractual term of the security. When we receive multiple deliveries of securities on the same day that are backed by the same pools of loans, we calculate the specific cost of each security as the average price of the trades that delivered those securities. As of December 31, 2015 , we did not have any securities classified as held-to-maturity, although we may elect to do so in the future. Fannie Mae MBS included in “Investments in securities” When we own Fannie Mae MBS issued by unconsolidated trusts, we do not derecognize any components of the guaranty assets, guaranty obligations, or any other outstanding recorded amounts associated with the guaranty transaction because our contractual obligation to the MBS trust remains in force until the trust is liquidated. We determine the fair value of Fannie Mae MBS based on observable market prices because most Fannie Mae MBS are actively traded. Fannie Mae MBS receive high credit quality ratings primarily because of our guaranty. The fair value of the guaranty obligation, net of deferred profit, associated with Fannie Mae MBS included in “Investments in securities” approximates the fair value of the credit risk that exists on these Fannie Mae MBS absent our guaranty. We disclose the aggregate amount of Fannie Mae MBS held as “Investments in securities” in our consolidated balance sheets. The unamortized obligation to stand ready to perform over the term of our guaranty and any incurred credit losses that relate to Fannie Mae MBS held as “Investments in securities” is included in “Other liabilities.” Upon subsequent sale of a Fannie Mae MBS, we continue to account for any outstanding recorded amounts associated with the guaranty transaction on the same basis of accounting as prior to the sale of Fannie Mae MBS, as no new assets were retained and no new liabilities have been assumed upon the subsequent sale.
Available-for-sale Securities, Policy [Policy Text Block]	Other-Than-Temporary Impairment of Debt Securities We evaluate AFS securities for other-than-temporary impairment (“OTTI”) on a quarterly basis. OTTI is considered to have occurred when the fair value of a debt security is below its amortized cost basis and we intend to sell or it is more likely than not that we will be required to sell the security before recovery. In such cases, we recognize in “Investment gains, net” in our consolidated statements of operations and comprehensive income the entire difference between the amortized cost basis of the security and its fair value. OTTI is also considered to have occurred if we do not expect to recover the entire amortized cost basis of a debt security even if we do not intend to sell the security or it is not more likely than not we will be required to sell the security before recovery. We separate the difference between the amortized cost basis of the security and its fair value into the amount representing the credit loss, which we recognize in “Investment gains, net” in our consolidated statements of operations and comprehensive income, and the amount related to all other factors, which we recognize in “Other comprehensive income (loss),” net of taxes. We consider guarantees, insurance contracts or other credit enhancements (such as collateral) in determining our best estimate of cash flows expected to be collected only if (1) such guarantees, insurance contracts or other credit enhancements provide for payments to be made solely to reimburse us for failure of the issuer to satisfy its required payment obligations; (2) such guarantees, insurance contracts or other credit enhancements are contractually attached to the security; and (3) collection of the amounts receivable under these agreements is deemed probable. Guarantees, insurance contracts or other credit enhancements are considered contractually attached if they are part of and trade with the security upon transfer of the security to a third party. In periods after we recognize OTTI of debt securities, we use the prospective interest method to recognize interest income. Under the prospective interest method, we calculate a new effective yield for subsequent recognition of interest income and measurement of impairment when we determine that there has been a significant increase in expected or actual cash flows. We consider a significant increase in cash flows to be at least a 10% increase over two consecutive quarters of the expected or actual cash flows. We calculate the new effective yield by using the new cost basis and the significantly increased actual or expected cash flows. Available-for-Sale Securities We record 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 consolidated statements of operations and comprehensive income. Other-Than-Temporary Impairments For AFS securities, OTTI is considered to have occurred when the fair value of a debt security is below its amortized cost basis and we intend to sell or it is more likely than not that we will be required to sell the security before recovery. Additionally, OTTI is considered to have occurred if we do not expect to recover the entire amortized cost basis of a debt security even if we do not intend to sell the security or it is not more likely than not we will be required to sell the security before recovery.
Finance, Loan and Lease Receivables, Held-for-sale, Policy [Policy Text Block]	Loans Held for Sale When we acquire mortgage loans that we intend to sell or securitize via trusts that will not be consolidated, we classify the loans as HFS. We report HFS loans at the lower of cost or fair value. Any excess of an HFS loan’s cost over its fair value is recognized as a valuation allowance, with changes in the valuation allowance recognized as “Investment gains, net” in our consolidated statements of operations and comprehensive income. We recognize interest income on HFS loans on an accrual basis, unless we determine that the ultimate collection of contractual principal or interest payments in full is not reasonably assured. Purchased premiums, discounts and other cost basis adjustments on HFS loans are deferred upon loan acquisition, included in the cost basis of the loan, and not amortized. We determine any lower of cost or fair value adjustment on HFS loans at an individual loan level. In the event that we reclassify HFI loans to HFS loans, we record the loans at lower of cost or fair value on the date of reclassification. We recognize any lower of cost or fair value adjustment recognized upon reclassification through the provision for credit losses. We report the carrying value of HFS loans at the lower of cost or fair value and record valuation changes in our consolidated statements of operations and comprehensive income.
Finance, Loan and Lease Receivables, Held-for-investment, Policy [Policy Text Block]	Loans Held for Investment When we acquire mortgage loans that we have the ability and the intent to hold for the foreseeable future or until maturity, we classify the loans as HFI. When we consolidate a trust, we recognize the loans underlying the trust in our consolidated balance sheets. The trusts do not have the ability to sell mortgage loans and the use of such loans is limited exclusively to the settlement of obligations of the trusts. Therefore, mortgages acquired when we have the intent to securitize via trusts that are consolidated will generally be classified as HFI in our consolidated balance sheets both prior to and subsequent to their securitization. We report HFI loans at the unpaid principal balance, net of unamortized premiums and discounts, other cost basis adjustments, and allowance for loan losses. We recognize interest income on HFI loans on an accrual basis using the interest method over the contractual life of the loan, including the amortization of any deferred cost basis adjustments, such as the premium or discount at acquisition, unless we determine that the ultimate collection of contractual principal or interest payments in full is not reasonably assured. We define the recorded investment of HFI loans as unpaid principal balance, net of unamortized premiums and discounts, other cost basis adjustments, and accrued interest receivable. We report the carrying value of HFI loans at the unpaid principal balance, net of unamortized premiums and discounts, other cost basis adjustments, and an allowance for loan losses.
Nonaccrual Loans [Policy Text Block]	Nonaccrual Loans We discontinue accruing interest on loans when we believe collectibility of principal or interest is not reasonably assured, which for a single-family loan we have determined, based on our historical experience, to be when the loan becomes two months or more past due according to its contractual terms. Interest previously accrued but not collected is reversed through interest income at the date a loan is placed on nonaccrual status. We return a non-modified single-family loan to accrual status at the point that the borrower brings the loan current. We return a 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 the modification is made permanent. We place a multifamily loan on nonaccrual status when the loan becomes three months or more past due according to its contractual terms or is deemed to be individually impaired, unless the loan is well secured such that collectibility of principal and accrued interest is reasonably assured. We return a multifamily loan to accrual status when the borrower cures the delinquency of the loan or we otherwise determine that the loan is well secured such that collectibility is reasonably assured.
Troubled Debt Restructurings [Policy Text Block]	Restructured Loans A modification to the contractual terms of a loan that results in granting a concession to a borrower experiencing financial difficulties is considered a troubled debt restructuring (“TDR”). Our loss mitigation programs primarily include modifications that result in the capitalization of past due amounts in combination with interest rate reductions and/or the extension of the loan’s maturity date. Such restructurings are granted to borrowers in financial difficulty on either a permanent or contingent basis, as in the case of modifications with a trial period. We consider these types of loan restructurings to be TDRs. We do not include principal or past due interest forgiveness as part of our loss mitigation programs, and as a result, we do not charge off any outstanding principal or accrued interest amounts at the time of loan modification. We believe that the loan underwriting activities we perform as a part of our loan modification process coupled with the borrower’s successful performance during any required trial period provide us reasonable assurance regarding the collectibility of the principal and interest due in accordance with the loan’s modified terms, which include any past due interest amounts that are capitalized as principal at the time of modification. As such, the loan is returned to accrual status when the loan modification is completed ( i.e ., at the end of the trial period), and we accrue interest thereafter in accordance with our interest accrual policy. If the loan was on nonaccrual status prior to entering the trial period, it remains on nonaccrual status until the borrower demonstrates performance via the trial period and the modification is finalized. In addition to these loan modifications, we also engage in other loss mitigation activities with troubled borrowers, which include repayment plans, forbearance arrangements, and the capitalization only of past due amounts. Repayment plans and forbearance arrangements are informal agreements with the borrower that do not result in the legal modification of the loan. For all of these activities, we consider the deferral or capitalization of three or fewer missed payments to represent only an insignificant delay, and thus not a TDR. If we defer or capitalize more than three missed payments, the delay is no longer considered insignificant, and the restructuring is accounted for as a TDR. We measure impairment of a loan restructured in a TDR individually based on the excess of the recorded investment in the loan over the present value of the expected future cash inflows discounted at the loan’s original effective interest rate. Costs incurred to complete a TDR are expensed as incurred. However, when foreclosure is probable on an individually impaired loan, we measure impairment based on the difference between our recorded investment in the loan and the fair value of the underlying property, adjusted for the estimated costs to sell the property and estimated insurance or other proceeds we expect to receive. 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 [Policy Text Block]	Allowance for Loan Losses and Reserve for Guaranty 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 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, upon the redesignation of nonperforming loans from HFI to HFS and pursuant to the charge-off provisions of the Advisory Bulletin. The reserve for guaranty losses is a liability account which is a component of “Other liabilities” in our consolidated balance sheets that reflects an estimate of incurred credit losses related to our guaranty to each unconsolidated Fannie Mae MBS trust that we will supplement amounts received by the Fannie Mae MBS trust as required to permit timely payments of principal and interest on the related Fannie Mae MBS and our agreements to purchase credit-impaired loans from lenders under the terms of our long-term standby commitments. As a result, the reserve for guaranty losses considers not only the principal and interest due on the loan at the current balance sheet date, but also any additional interest payments due to the trust from the current balance sheet date until the point of loan acquisition or foreclosure.
Impaired Financing Receivable, Policy [Policy Text Block]	Single-Family Loans We recognize credit losses related to groups of similar single-family HFI loans that are not individually impaired when (1) available information as of each balance sheet date indicates that it is probable a loss has occurred and (2) the amount of the loss can be reasonably estimated. We aggregate such loans, based on similar risk characteristics, for purposes of estimating incurred credit losses and establish a collective single-family loss reserve using an econometric model that derives an overall loss reserve estimate. The estimate takes into account multiple factors which include but are not limited to origination year, loan product type, mark-to-market loan-to-value (“LTV”) ratio, and delinquency status. Once loans are aggregated, there typically is not a single, distinct event that would result in an individual loan or pool of loans being impaired. In determining our collective reserve, we base our allowance methodology on historical events and trends, such as loss severity (in event of default), default rates, and recoveries from mortgage insurance contracts and other credit enhancements that provide loan level loss coverage and are either contractually attached to a loan or that were entered into contemporaneously with and in contemplation of a guaranty or loan purchase transaction. We use recent regional historical sales and appraisal information, including the sales of our own foreclosed properties, to develop our loss severity estimates for all loan categories. Our allowance calculation also incorporates a loss confirmation period (the anticipated time lag between a credit loss event and the confirmation of the credit loss resulting from that event) to ensure our allowance estimate captures credit losses that have been incurred as of the balance sheet date but have not been confirmed. In addition, management performs a review of the observable data used in its estimate to ensure it is representative of prevailing economic conditions and other events existing as of the balance sheet date. We record charge-offs as a reduction to the allowance for loan losses or reserve for guaranty 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, upon the redesignation of nonperforming loans from HFI to HFS and pursuant to the charge-off provisions of the Advisory Bulletin. The excess of a loan’s unpaid principal balance, accrued interest, and any applicable cost basis adjustments (“our total exposure”) over the fair value of the assets is treated as a charge-off loss that is deducted from the allowance for loan losses or reserve for guaranty losses. The amount charged off also considers estimated proceeds from primary mortgage insurance or other credit enhancements that are either contractually attached to a loan or that were entered into contemporaneously with and in contemplation of a guaranty or loan purchase transaction as a recovery of our total exposure, up to the amount of loss recognized as a charge-off. We record additional proceeds from primary mortgage insurance and credit enhancements in excess of our total exposure as a recovery of any forgone contractually past due interest, and then as an offset to the expenses recorded in “Foreclosed property expense (income)” in our consolidated statements of operations and comprehensive income when received. Individually Impaired Single-Family Loans Individually impaired single-family loans currently include those restructured in a TDR and acquired credit-impaired loans. We consider a loan to be impaired when, based on current information, it is probable that we will not receive all amounts due, including interest, in accordance with the contractual terms of the loan agreement. When making our assessment as to whether a loan is impaired, we also take into account more than insignificant delays in payment and shortfalls in amounts received. Determination of whether a delay in payment or shortfall in amount is more than insignificant requires management’s judgment as to the facts and circumstances surrounding the loan. Our measurement of impairment on an individually impaired loan follows the method that is most consistent with our expectations of recovery of our recorded investment in the loan. When a loan has been restructured, we measure impairment using a cash flow analysis discounted at the loan’s original effective interest rate. If we expect to recover our recorded investment in an individually impaired loan through probable foreclosure of the underlying collateral, we measure impairment based on the fair value of the collateral, reduced by estimated disposal costs on a discounted basis and adjusted for estimated proceeds from mortgage, flood, or hazard insurance or similar sources. For individually impaired loans that we believe are probable of foreclosure, we take into consideration the sales prices of foreclosed properties in determining the value of the underlying real estate collateral. We use internal models to project cash flows used to assess impairment of individually impaired loans, and generally update the market and loan characteristic inputs we use in these models monthly, using month-end data. Market inputs include information such as interest rates, volatility and spreads, while loan characteristic inputs include information such as mark-to-market LTV ratios and delinquency status. The loan characteristic inputs are key factors that affect the predicted rate of default for loans evaluated for impairment through our internal cash flow models. For example, loans with an unsuccessful trial modification, which are often accompanied by high delinquency rates, have much higher predicted default rates compared to performing loans with completed modifications, particularly those with a significant payment reduction in the borrower’s required monthly payment. We evaluate the reasonableness of our models by comparing the results with actual performance and our assessment of current market conditions. In addition, we review our models at least annually for reasonableness and predictive ability in accordance with our corporate model review policy. Accordingly, we believe the projected cash flows generated by our models that we use to assess impairment appropriately reflect the expected future performance of the loans. Multifamily Loans 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 multifamily 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. We categorize loan credit risk based on relevant observable data about a borrower’s ability to pay, including multifamily market economic fundamentals, review of available current borrower financial information, operating statements on the underlying collateral, current debt service coverage ratios (“DSCRs”), historical payment experience, estimates of the current collateral values and other related credit documentation. For each risk category, certain observed default probability and loss severity (in event of default) factors, based on historical performance of loans in the same risk category, are applied against our recorded investment in the loans to determine an appropriate allowance. Such performance data reflect historical delinquencies and charge-offs, as well as loan size. In addition, we consider any credit enhancements such as letters of credit or loss sharing arrangements with our lenders
Advances to Lenders [Policy Text Block]	Advances to Lenders Advances to lenders represent our payments of cash in exchange for the receipt of mortgage loans from lenders in a transfer that is accounted for as a secured lending arrangement. These transfers primarily occur when we provide early funding to lenders for loans that they will subsequently either sell to us or securitize into a Fannie Mae MBS that they will deliver to us. We individually negotiate early lender funding advances with our lender customers. Early lender funding advances have terms up to 60 days and earn a short-term market rate of interest. We report cash outflows from advances to lenders as an investing activity in our consolidated statements of cash flows. Settlements of the advances to lenders, other than through lender repurchases of loans, are not collected in cash, but rather in the receipt of either loans or Fannie Mae MBS. Accordingly, this activity is reflected as a non-cash transfer in our consolidated statements of cash flows in the line item entitled “Transfers from advances to lenders to loans held for investment of consolidated trusts.”
Finance, Loan and Lease Receivables, Held for Investments, Foreclosed Assets Policy [Policy Text Block]	Acquired Property, Net We recognize foreclosed property ( i.e. , “Acquired property, net”) upon the earlier of the loan foreclosure event or when we take physical possession of the property ( i.e. , through a deed-in-lieu of foreclosure transaction). We initially measure foreclosed property at its fair value less its estimated costs to sell. We treat any excess of our recorded investment in the loan over the fair value less estimated costs to sell the property as a charge-off to the “Allowance for loan losses.” Any excess of the fair value less estimated costs to sell the property over our recorded investment in the loan is recognized first to recover any forgone, contractually due interest, then to “Foreclosed property expense (income)” in our consolidated statements of operations and comprehensive income. We classify foreclosed properties as HFS when we intend to sell the property and the following conditions are met at either acquisition or within a relatively short period thereafter: we are actively marketing the property and it is available for immediate sale in its current condition such that the sale is reasonably expected to take place within one year. We report these properties at the lower of their carrying amount or fair value less estimated selling costs. We do not depreciate these properties. We recognize a loss for any subsequent write-down of the property to its fair value less its estimated costs to sell through a valuation allowance with an offsetting charge to “Foreclosed property expense (income)” in our consolidated statements of operations and comprehensive income. We recognize a recovery for any subsequent increase in fair value less estimated costs to sell up to the cumulative loss previously recognized through the valuation allowance. We recognize gains or losses on sales of foreclosed property through “Foreclosed property expense (income)” in our consolidated statements of operations and comprehensive income. Properties that do not meet the criteria to be classified as HFS are classified as held for use and are recorded in “Other assets” in our consolidated balance sheets. These properties are depreciated and are evaluated for impairment when circumstances indicate that the carrying amount of the property is no longer recoverable. 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, are actively marketing it and it is ready for immediate sale in its current condition.
Commitments to Purchase and Sell Mortgage Loans and Securities [Policy Text Block]	Commitments to Purchase and Sell Mortgage Loans and Securities We enter into commitments to purchase and sell mortgage-backed securities and to purchase single-family and multifamily mortgage loans. Certain commitments to purchase or sell mortgage-backed securities and to purchase single-family mortgage loans are generally accounted for as derivatives. Our commitments to purchase multifamily loans are not accounted for as derivatives because they do not meet the criteria for net settlement. When derivative purchase commitments settle, we include the fair value on the settlement date in the cost basis of the loan or unconsolidated security we purchase. When derivative commitments to sell securities settle, we include the fair value of the commitment on the settlement date in the cost basis of the security we sell. Purchases and sales of securities issued by our consolidated MBS trusts are treated as extinguishment or issuance of debt, respectively. For commitments to purchase and sell securities issued by our consolidated MBS trusts, we recognize the fair value of the commitment on the settlement date as a component of debt extinguishment gains and losses or in the cost basis of the debt issued, respectively. Regular-way securities trades provide for delivery of securities within the time generally established by regulations or conventions in the market in which the trade occurs and are exempt from application of derivative accounting. Commitments to purchase or sell securities that we account for on a trade-date basis are also exempt from the derivative accounting requirements. We record the purchase and sale of an existing security on its trade date when the commitment to purchase or sell the existing security settles within the period of time that is customary in the market in which those trades take place. Additionally, contracts for the forward purchase or sale of when-issued and to-be-announced (“TBA”) securities are exempt from the derivative accounting requirements if there is no other way to purchase or sell that security, delivery of that security and settlement will occur within the shortest period possible for that type of security, and it is probable at inception and throughout the term of the individual contract that physical delivery of the security will occur. Since our commitments for the purchase of when-issued and TBA securities can be net settled and we do not document that physical settlement is probable, we account for all such commitments as derivatives.
Derivatives, Policy [Policy Text Block]	Derivative Instruments We recognize all derivatives as either assets or liabilities in our consolidated balance sheets at their fair value on a trade date basis. We report derivatives in a gain position after offsetting by counterparty in “Other assets” and derivatives in a loss position after offsetting by counterparty in “Other liabilities” in our consolidated balance sheets. • Interest rate swap contracts. An interest rate swap is a transaction between two parties in which each party agrees to exchange payments tied to different interest rates or indices for a specified period of time, generally based on a notional amount of principal. The types of interest rate swaps we use include pay-fixed swaps, receive-fixed swaps and basis swaps. • Interest rate option contracts. These contracts primarily include pay-fixed swaptions, receive-fixed swaptions, cancelable swaps and interest rate caps. A swaption is an option contract that allows us or a counterparty to enter into a pay-fixed or receive-fixed swap at some point in the future. • Foreign currency swaps. These swaps convert debt that we issue in foreign denominated currencies into U.S. dollars. We enter into foreign currency swaps only to the extent that we hold foreign currency debt. • Futures. These are standardized exchange-traded contracts that either obligate a buyer to buy an asset at a predetermined date and price or a seller to sell an asset at a predetermined date and price. The types of futures contracts we enter into include Eurodollar, U.S. Treasury and swaps.
Derivatives, Offsetting Fair Value Amounts, Policy [Policy Text Block]	We offset the carrying amounts of certain derivatives that are in gain positions and loss positions with the same counterparty as well as cash collateral receivables and payables associated with derivative positions under master netting arrangements. We offset these amounts only when we have the legal right to offset under the contract and we have met all of the offsetting conditions. 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. Derivative instruments are recorded at fair value and securities purchased under agreements to resell or similar arrangements are recorded at amortized cost in our consolidated balance sheets.
Derivatives, Embedded Derivatives [Policy Text Block]	We evaluate financial instruments that we purchase or issue and other financial and non-financial contracts for embedded derivatives. To identify embedded derivatives that we must account for separately, we determine if: (1) the economic characteristics of the embedded derivative are not clearly and closely related to the economic characteristics of the financial instrument or other contract ( i.e ., the host contract); (2) the financial instrument or other contract itself is not already measured at fair value with changes in fair value included in earnings; and (3) a separate instrument with the same terms as the embedded derivative would meet the definition of a derivative. If the embedded derivative meets all three of these conditions we elect to carry the hybrid contract in its entirety at fair value with changes in fair value recorded in earnings.
Repurchase Agreements, Collateral, Policy [Policy Text Block]	Collateral We enter into various transactions where we pledge and accept collateral, the most common of which are our derivative transactions. Required collateral levels vary depending on the credit rating and type of counterparty. We also pledge and receive collateral under our repurchase and reverse repurchase agreements. In order to reduce potential exposure to repurchase counterparties, a third-party custodian typically maintains the collateral and any margin. We monitor the fair value of the collateral received from our counterparties, and we may require additional collateral from those counterparties, as we deem appropriate. Cash Collateral We record cash collateral accepted from a counterparty that we have the right to use as “Cash and cash equivalents” and cash collateral accepted from a counterparty that we do not have the right to use as “Restricted cash” in our consolidated balance sheets. We net our obligation to return cash collateral pledged to us against the fair value of derivatives in a gain position recorded in “Other assets” in our consolidated balance sheets as part of our counterparty netting calculation. For derivative positions with the same counterparty under master netting arrangements where we pledge cash collateral, we remove it from “Cash and cash equivalents” and net the right to receive it against the fair value of derivatives in a loss position recorded in “Other liabilities” in our consolidated balance sheets as a part of our counterparty netting calculation. Non-Cash Collateral We classify securities pledged to counterparties as either “Investments in securities” or “Cash and cash equivalents” in our consolidated balance sheets. Securities pledged to counterparties that have been consolidated with the underlying assets recognized as loans are included as “Mortgage loans” in our consolidated balance sheets. Our liability to third party holders of Fannie Mae MBS that arises as the result of a consolidation of a securitization trust is collateralized by the underlying loans and/or mortgage-related securities.
Debt, Policy [Policy Text Block]	Debt Our consolidated balance sheets contain debt of Fannie Mae as well as debt of consolidated trusts. We report debt issued by us as “Debt of Fannie Mae” and by consolidated trusts as “Debt of consolidated trusts.” Debt issued by us represents debt that we issue to third parties to fund our general business activities and our credit risk-sharing securities. The debt of consolidated trusts represents the amount of Fannie Mae MBS issued from such trusts which is held by third-party certificateholders and prepayable without penalty at any time. We report deferred items, including premiums, discounts and other cost basis adjustments, as adjustments to the related debt balances in our consolidated balance sheets. We remeasure the carrying amount, accrued interest and basis adjustments of debt denominated in a foreign currency into U.S. dollars using foreign exchange spot rates as of the balance sheet dates and report any associated gains or losses as a component of “Fair value gains (losses), net” in our consolidated statements of operations and comprehensive income. When we purchase a Fannie Mae MBS issued from a consolidated single-class securitization trust, we extinguish the related debt of the consolidated trust as the MBS debt is no longer owed to a third-party. We record debt extinguishment gains or losses related to debt of consolidated trusts to the extent that the purchase price of the MBS does not equal the carrying value of the related consolidated MBS debt reported in our consolidated balance sheets (including unamortized premiums, discounts and other cost basis adjustments) at the time of purchase.
Interest Expense, Policy [Policy Text Block]	We classify interest expense as either short-term or long-term based on the contractual maturity of the related debt. We recognize the amortization of premiums, discounts and other cost basis adjustments through interest expense using the effective interest method usually over the contractual term of the debt. Amortization of premiums, discounts and other cost basis adjustments begins at the time of debt issuance. We remeasure interest expense for debt denominated in a foreign currency into U.S. dollars using the daily spot rates. The difference in rates arising from the month-end spot exchange rate used to calculate the interest accruals and the daily spot rates used to record the interest expense is a foreign currency transaction gain or loss for the period and is recognized as a component of “Fair value gains (losses), net” in our consolidated statements of operations and comprehensive income.
Income Tax, Policy [Policy Text Block]	Income Taxes We recognize deferred tax assets and liabilities based on the differences in the book and tax bases of assets and liabilities. We measure deferred tax assets and liabilities using enacted tax rates that are applicable to the period(s) that the differences are expected to reverse. We adjust deferred tax assets and liabilities for the effects of changes in tax laws and rates in the period of enactment. We recognize investment and other tax credits through our effective tax rate calculation assuming that we will be able to realize the full benefit of the credits. We reduce our deferred tax assets by an allowance if, based on the weight of available positive and negative evidence, it is more likely than not (a probability of greater than 50%) that we will not realize some portion, or all, of the deferred tax asset. We recognize deferred tax assets and liabilities for future tax consequences arising from differences between the carrying amounts of existing assets and liabilities under GAAP and their respective tax bases.
Income Tax Uncertainties, Policy [Policy Text Block]	We account for uncertain tax positions using a two-step approach whereby we recognize an income tax benefit if, based on the technical merits of a tax position, it is more likely than not that the tax position would be sustained upon examination by the taxing authority, which includes all related appeals and litigation. We then measure the recognized tax benefit based on the largest amount of tax benefit that is greater than 50% likely to be realized upon settlement with the taxing authority, considering all information available at the reporting date. We recognize interest expense and penalties on unrecognized tax benefits as “Other expenses, net” in our consolidated statements of operations and comprehensive income.
Earnings Per Share, Policy [Policy Text Block]	Earnings (Loss) per Share Earnings (loss) per share (“EPS”) is presented for both basic EPS and diluted EPS. We compute basic EPS by dividing net income (loss) attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period. In addition to common shares outstanding, the computation of basic EPS includes instruments for which the holder has (or is deemed to have) the present rights as of the end of the reporting period to share in current period earnings (loss) with common stockholders ( i.e., participating securities and common shares that are currently issuable for little or no cost to the holder). We include in the denominator of our basic EPS computation the weighted-average number of shares of common stock that would be issued upon the full exercise of the warrant issued to Treasury. Diluted EPS includes all the components of basic EPS, plus the dilutive effect of common stock equivalents such as convertible securities and stock options, but excludes those common stock equivalents from the calculation of diluted EPS when the effect of inclusion, assessed individually, would be anti-dilutive. The calculation of income available to common stockholders and EPS is based on the underlying premise that all income after payment of dividends on preferred shares is available to and will be distributed to the common stockholders. However, as a result of our conservatorship status and the terms of the senior preferred stock purchase agreement with Treasury, no amounts are available to distribute as dividends to common or preferred stockholders (other than to Treasury as holder of the senior preferred stock).
Compensatory Fees, Policy [Policy Text Block]	Compensatory Fees We charge our primary servicers a compensatory fee for servicing delays within their control when they fail to comply with our established loss mitigation and foreclosure timelines. Compensatory fees are intended to compensate us for damages attributed to such servicing delays and to emphasize the importance of servicer performance. We recognize a compensatory fee receivable when the amounts are chargeable per our guidelines and are considered reasonably assured of collection. We subsequently establish a valuation allowance for any amounts we estimate to be uncollectible. If such fees are not reasonably assured of collection, we recognize them on a cash basis when received. The income associated with these fees is recognized as a component of “Foreclosed property expense (income)” in our consolidated statements of operations and comprehensive income.
New Accounting Pronouncements, Policy [Policy Text Block]	New Accounting Guidance In May 2014, the Financial Accounting Standards Board (“FASB”) issued guidance on revenue from contracts with customers. The standard outlines a single model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance. The following contracts with customers are excluded from the scope of the new standard and will continue to be accounted for under existing guidance: leases, insurance, financial instruments (e.g., receivables, investments, liabilities, debt and derivatives) and guarantees. The new guidance is effective for us on January 1, 2018. We have evaluated this guidance and determined it will not have a material impact on our consolidated financial statements. 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. We have evaluated this guidance and determined it will not have a material impact on our consolidated financial statements. In January 2016, the FASB issued guidance which makes limited amendments to the accounting related to the classification and measurement of financial instruments. The new guidance revises the accounting requirements related to (1) the classification and measurement of investments in equity securities and (2) the presentation of certain fair value changes for financial liabilities measured at fair value. It also amends certain disclosure requirements associated with the fair value of financial instruments. The new guidance is effective for us on January 1, 2018. We have evaluated this guidance and determined it will not have a material impact on our consolidated financial statements.

Consolidation and Transfer of F

Consolidation and Transfer of Financial Assets (Policies)	12 Months Ended
	Dec. 31, 2015
Consolidations and Transfers of Financial Assets [Abstract]
Consolidations, Policy [Policy Text Block]	Principles of Consolidation Our consolidated financial statements include our accounts as well as the accounts of the other entities in which we have a controlling financial interest. All intercompany balances and transactions have been eliminated. The typical condition for a controlling financial interest is ownership of a majority of the voting interests of an entity. A controlling financial interest may also exist in entities through arrangements that do not involve voting interests, such as a VIE. We have interests in various entities that are considered to be 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.
Transfers and Servicing of Financial Assets, Policy [Policy Text Block]	Transfers of Financial Assets We evaluate a transfer of financial assets to determine whether the transfer qualifies as a sale. If the transfer does not meet the criteria for sale treatment, the transferred assets remain in our consolidated balance sheets and we record a liability to the extent of any proceeds received in connection with such a transfer. Transfers of financial assets for which we surrender control of the transferred assets are recorded as sales. When a transfer that qualifies as a sale is completed, we derecognize all assets transferred and recognize all assets obtained and liabilities incurred at fair value. The difference between the carrying basis of the assets transferred and the fair value of the proceeds from the sale is recorded as a component of “Investment gains, net” in our consolidated statements of operations and comprehensive income. Retained interests are primarily derived from transfers associated with our portfolio securitizations in the form of Fannie Mae MBS, REMIC certificates, guaranty assets and master servicing assets (“MSAs”). We separately describe the subsequent accounting, as well as how we determine fair value, for our retained interests in the Fannie Mae MBS included in the “Investments in Securities” section of this note. We enter into repurchase agreements that involve contemporaneous trades to purchase and sell securities. These transactions are accounted for as secured financings since the transferor has not relinquished control over the transferred assets. These transactions are reported as securities purchased under agreements to resell and securities sold under agreements to repurchase in our consolidated balance sheets except for securities purchased under agreements to resell on an overnight basis, which are included in cash and cash equivalents in our consolidated balance sheets. 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)	12 Months Ended
	Dec. 31, 2015
Mortgage Loans on Real Estate [Abstract]
Finance, Loan and Lease Receivables, Held-for-investment, Policy [Policy Text Block]	Loans Held for Investment When we acquire mortgage loans that we have the ability and the intent to hold for the foreseeable future or until maturity, we classify the loans as HFI. When we consolidate a trust, we recognize the loans underlying the trust in our consolidated balance sheets. The trusts do not have the ability to sell mortgage loans and the use of such loans is limited exclusively to the settlement of obligations of the trusts. Therefore, mortgages acquired when we have the intent to securitize via trusts that are consolidated will generally be classified as HFI in our consolidated balance sheets both prior to and subsequent to their securitization. We report HFI loans at the unpaid principal balance, net of unamortized premiums and discounts, other cost basis adjustments, and allowance for loan losses. We recognize interest income on HFI loans on an accrual basis using the interest method over the contractual life of the loan, including the amortization of any deferred cost basis adjustments, such as the premium or discount at acquisition, unless we determine that the ultimate collection of contractual principal or interest payments in full is not reasonably assured. We define the recorded investment of HFI loans as unpaid principal balance, net of unamortized premiums and discounts, other cost basis adjustments, and accrued interest receivable. We report the carrying value of HFI loans at the unpaid principal balance, net of unamortized premiums and discounts, other cost basis adjustments, and an allowance for loan losses.
Finance, Loan and Lease Receivables, Held-for-sale, Policy [Policy Text Block]	Loans Held for Sale When we acquire mortgage loans that we intend to sell or securitize via trusts that will not be consolidated, we classify the loans as HFS. We report HFS loans at the lower of cost or fair value. Any excess of an HFS loan’s cost over its fair value is recognized as a valuation allowance, with changes in the valuation allowance recognized as “Investment gains, net” in our consolidated statements of operations and comprehensive income. We recognize interest income on HFS loans on an accrual basis, unless we determine that the ultimate collection of contractual principal or interest payments in full is not reasonably assured. Purchased premiums, discounts and other cost basis adjustments on HFS loans are deferred upon loan acquisition, included in the cost basis of the loan, and not amortized. We determine any lower of cost or fair value adjustment on HFS loans at an individual loan level. In the event that we reclassify HFI loans to HFS loans, we record the loans at lower of cost or fair value on the date of reclassification. We recognize any lower of cost or fair value adjustment recognized upon reclassification through the provision for credit losses. We report the carrying value of HFS loans at the lower of cost or fair value and record valuation changes in our consolidated statements of operations and comprehensive income.
Troubled Debt Restructurings [Policy Text Block]	Restructured Loans A modification to the contractual terms of a loan that results in granting a concession to a borrower experiencing financial difficulties is considered a troubled debt restructuring (“TDR”). Our loss mitigation programs primarily include modifications that result in the capitalization of past due amounts in combination with interest rate reductions and/or the extension of the loan’s maturity date. Such restructurings are granted to borrowers in financial difficulty on either a permanent or contingent basis, as in the case of modifications with a trial period. We consider these types of loan restructurings to be TDRs. We do not include principal or past due interest forgiveness as part of our loss mitigation programs, and as a result, we do not charge off any outstanding principal or accrued interest amounts at the time of loan modification. We believe that the loan underwriting activities we perform as a part of our loan modification process coupled with the borrower’s successful performance during any required trial period provide us reasonable assurance regarding the collectibility of the principal and interest due in accordance with the loan’s modified terms, which include any past due interest amounts that are capitalized as principal at the time of modification. As such, the loan is returned to accrual status when the loan modification is completed ( i.e ., at the end of the trial period), and we accrue interest thereafter in accordance with our interest accrual policy. If the loan was on nonaccrual status prior to entering the trial period, it remains on nonaccrual status until the borrower demonstrates performance via the trial period and the modification is finalized. In addition to these loan modifications, we also engage in other loss mitigation activities with troubled borrowers, which include repayment plans, forbearance arrangements, and the capitalization only of past due amounts. Repayment plans and forbearance arrangements are informal agreements with the borrower that do not result in the legal modification of the loan. For all of these activities, we consider the deferral or capitalization of three or fewer missed payments to represent only an insignificant delay, and thus not a TDR. If we defer or capitalize more than three missed payments, the delay is no longer considered insignificant, and the restructuring is accounted for as a TDR. We measure impairment of a loan restructured in a TDR individually based on the excess of the recorded investment in the loan over the present value of the expected future cash inflows discounted at the loan’s original effective interest rate. Costs incurred to complete a TDR are expensed as incurred. However, when foreclosure is probable on an individually impaired loan, we measure impairment based on the difference between our recorded investment in the loan and the fair value of the underlying property, adjusted for the estimated costs to sell the property and estimated insurance or other proceeds we expect to receive. 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.

Investment in Securities Polici

Investment in Securities Policies (Policies)	12 Months Ended
	Dec. 31, 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 consolidated statements of operations and comprehensive income.
Available-for-sale Securities, Policy [Policy Text Block]	Other-Than-Temporary Impairment of Debt Securities We evaluate AFS securities for other-than-temporary impairment (“OTTI”) on a quarterly basis. OTTI is considered to have occurred when the fair value of a debt security is below its amortized cost basis and we intend to sell or it is more likely than not that we will be required to sell the security before recovery. In such cases, we recognize in “Investment gains, net” in our consolidated statements of operations and comprehensive income the entire difference between the amortized cost basis of the security and its fair value. OTTI is also considered to have occurred if we do not expect to recover the entire amortized cost basis of a debt security even if we do not intend to sell the security or it is not more likely than not we will be required to sell the security before recovery. We separate the difference between the amortized cost basis of the security and its fair value into the amount representing the credit loss, which we recognize in “Investment gains, net” in our consolidated statements of operations and comprehensive income, and the amount related to all other factors, which we recognize in “Other comprehensive income (loss),” net of taxes. We consider guarantees, insurance contracts or other credit enhancements (such as collateral) in determining our best estimate of cash flows expected to be collected only if (1) such guarantees, insurance contracts or other credit enhancements provide for payments to be made solely to reimburse us for failure of the issuer to satisfy its required payment obligations; (2) such guarantees, insurance contracts or other credit enhancements are contractually attached to the security; and (3) collection of the amounts receivable under these agreements is deemed probable. Guarantees, insurance contracts or other credit enhancements are considered contractually attached if they are part of and trade with the security upon transfer of the security to a third party. In periods after we recognize OTTI of debt securities, we use the prospective interest method to recognize interest income. Under the prospective interest method, we calculate a new effective yield for subsequent recognition of interest income and measurement of impairment when we determine that there has been a significant increase in expected or actual cash flows. We consider a significant increase in cash flows to be at least a 10% increase over two consecutive quarters of the expected or actual cash flows. We calculate the new effective yield by using the new cost basis and the significantly increased actual or expected cash flows. Available-for-Sale Securities We record 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 consolidated statements of operations and comprehensive income. Other-Than-Temporary Impairments For AFS securities, OTTI is considered to have occurred when the fair value of a debt security is below its amortized cost basis and we intend to sell or it is more likely than not that we will be required to sell the security before recovery. Additionally, OTTI is considered to have occurred if we do not expect to recover the entire amortized cost basis of a debt security even if we do not intend to sell the security or it is not more likely than not we will be required to sell the security before recovery.

Acquired Property, Net (Policie

Acquired Property, Net (Policies)	12 Months Ended
	Dec. 31, 2015
Real Estate [Abstract]
Finance, Loan and Lease Receivables, Held for Investments, Foreclosed Assets Policy [Policy Text Block]	Acquired Property, Net We recognize foreclosed property ( i.e. , “Acquired property, net”) upon the earlier of the loan foreclosure event or when we take physical possession of the property ( i.e. , through a deed-in-lieu of foreclosure transaction). We initially measure foreclosed property at its fair value less its estimated costs to sell. We treat any excess of our recorded investment in the loan over the fair value less estimated costs to sell the property as a charge-off to the “Allowance for loan losses.” Any excess of the fair value less estimated costs to sell the property over our recorded investment in the loan is recognized first to recover any forgone, contractually due interest, then to “Foreclosed property expense (income)” in our consolidated statements of operations and comprehensive income. We classify foreclosed properties as HFS when we intend to sell the property and the following conditions are met at either acquisition or within a relatively short period thereafter: we are actively marketing the property and it is available for immediate sale in its current condition such that the sale is reasonably expected to take place within one year. We report these properties at the lower of their carrying amount or fair value less estimated selling costs. We do not depreciate these properties. We recognize a loss for any subsequent write-down of the property to its fair value less its estimated costs to sell through a valuation allowance with an offsetting charge to “Foreclosed property expense (income)” in our consolidated statements of operations and comprehensive income. We recognize a recovery for any subsequent increase in fair value less estimated costs to sell up to the cumulative loss previously recognized through the valuation allowance. We recognize gains or losses on sales of foreclosed property through “Foreclosed property expense (income)” in our consolidated statements of operations and comprehensive income. Properties that do not meet the criteria to be classified as HFS are classified as held for use and are recorded in “Other assets” in our consolidated balance sheets. These properties are depreciated and are evaluated for impairment when circumstances indicate that the carrying amount of the property is no longer recoverable. 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, are actively marketing it and it is ready for immediate sale in its current condition.

Derivative Instruments Derivati

Derivative Instruments Derivative Policy (Policies)	12 Months Ended
	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives, Policy [Policy Text Block]	Derivative Instruments We recognize all derivatives as either assets or liabilities in our consolidated balance sheets at their fair value on a trade date basis. We report derivatives in a gain position after offsetting by counterparty in “Other assets” and derivatives in a loss position after offsetting by counterparty in “Other liabilities” in our consolidated balance sheets. • Interest rate swap contracts. An interest rate swap is a transaction between two parties in which each party agrees to exchange payments tied to different interest rates or indices for a specified period of time, generally based on a notional amount of principal. The types of interest rate swaps we use include pay-fixed swaps, receive-fixed swaps and basis swaps. • Interest rate option contracts. These contracts primarily include pay-fixed swaptions, receive-fixed swaptions, cancelable swaps and interest rate caps. A swaption is an option contract that allows us or a counterparty to enter into a pay-fixed or receive-fixed swap at some point in the future. • Foreign currency swaps. These swaps convert debt that we issue in foreign denominated currencies into U.S. dollars. We enter into foreign currency swaps only to the extent that we hold foreign currency debt. • Futures. These are standardized exchange-traded contracts that either obligate a buyer to buy an asset at a predetermined date and price or a seller to sell an asset at a predetermined date and price. The types of futures contracts we enter into include Eurodollar, U.S. Treasury and swaps.

Income Tax Policies (Policies)

Income Tax Policies (Policies)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Tax, Policy [Policy Text Block]	Income Taxes We recognize deferred tax assets and liabilities based on the differences in the book and tax bases of assets and liabilities. We measure deferred tax assets and liabilities using enacted tax rates that are applicable to the period(s) that the differences are expected to reverse. We adjust deferred tax assets and liabilities for the effects of changes in tax laws and rates in the period of enactment. We recognize investment and other tax credits through our effective tax rate calculation assuming that we will be able to realize the full benefit of the credits. We reduce our deferred tax assets by an allowance if, based on the weight of available positive and negative evidence, it is more likely than not (a probability of greater than 50%) that we will not realize some portion, or all, of the deferred tax asset. We recognize deferred tax assets and liabilities for future tax consequences arising from differences between the carrying amounts of existing assets and liabilities under GAAP and their respective tax bases.

Segment Reporting Policy (Polic

Segment Reporting Policy (Policies)	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Segment Reporting, Policy [Policy Text Block]	We operate under three business segments: Single-Family Credit Guaranty (“Single-Family”), Multifamily and Capital Markets. Our Single-Family segment generates revenue primarily from the guaranty fees on the mortgage loans underlying guaranteed single-family Fannie Mae mortgage-backed securities (“Fannie Mae MBS”). Our Multifamily segment generates revenue from a variety of sources, including guaranty fees on the mortgage loans underlying multifamily Fannie Mae MBS, transaction fees associated with the multifamily business and bond credit enhancement fees. Our Capital Markets segment invests in mortgage loans, mortgage-related securities and other investments, and generates income primarily from the difference, or spread, between the yield on the mortgage assets we own and the interest we pay on the debt we issue in the global capital markets to fund the purchases of these mortgage assets. 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 structure, the sum of the results for our three business segments does not equal our consolidated results of operations as we separate the activity related to our consolidated trusts from the results generated by our three segments. In addition, we apply accounting methods for segment reporting purposes that differ from our consolidated results. Therefore, we reconcile the sum of the results for our three business segments to our consolidated results of operations.

Netting Arrangements (Policies)

Netting Arrangements (Policies)	12 Months Ended
	Dec. 31, 2015
Offsetting [Abstract]
Derivatives, Offsetting Policy [Policy Text Block]	We offset the carrying amounts of certain derivatives that are in gain positions and loss positions with the same counterparty as well as cash collateral receivables and payables associated with derivative positions under master netting arrangements. We offset these amounts only when we have the legal right to offset under the contract and we have met all of the offsetting conditions. 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. Derivative instruments are recorded at fair value and securities purchased under agreements to resell or similar arrangements are recorded at amortized cost in our consolidated balance sheets.

Fair Value (Policies)

Fair Value (Policies)	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurement, Policy [Policy Text Block]	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. 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.

Commitments and Contingencies P

Commitments and Contingencies Policy (Policies)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies: Policy [Policy Text Block]	We establish an accrual for matters when a loss is probable and we can reasonably estimate the amount of such loss. On a quarterly basis, we review relevant information about all pending legal actions and proceedings for the purpose of evaluating and revising our contingencies, accruals and disclosures. For legal actions or proceedings where there is only a reasonable possibility that a loss may be incurred, or where we are not currently able to estimate the reasonably possible loss or range of loss, we do not establish an accrual.
Loan and Mortgage Related Securities Commitments: Policy [Policy Text Block]	We have unconditional commitments related to the purchase of loans and mortgage-related securities. These include both on- and off-balance sheet commitments. A portion of these have been recorded as derivatives in our consolidated balance sheets.

Consolidations and Transfers 39

Consolidations and Transfers of Financial Assets (Tables)	12 Months Ended
	Dec. 31, 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 of December 31, 2015 2014 (Dollars in millions) Assets and liabilities recorded in our consolidated balance sheets related to mortgage-backed trusts: Assets: Trading securities: Fannie Mae securities $ 4,704 $ 4,790 Non-Fannie Mae securities 5,596 7,073 Total trading securities 10,300 11,863 Available-for-sale securities: Fannie Mae securities 3,936 5,043 Non-Fannie Mae securities 14,644 22,776 Total available-for-sale securities 18,580 27,819 Other assets 100 111 Other liabilities (827 ) (1,440 ) Net carrying amount $ 28,153 $ 38,353

Mortgage Loans (Tables)

Mortgage Loans (Tables)	12 Months Ended
	Dec. 31, 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 December 31, 2015 2014 Of Fannie Mae Of Consolidated Trusts Total Of Fannie Mae Of Consolidated Trusts Total (Dollars in millions) Single-family $ 238,237 $ 2,574,174 $ 2,812,411 $ 262,116 $ 2,569,884 $ 2,832,000 Multifamily 13,099 185,243 198,342 23,255 164,045 187,300 Total unpaid principal balance of mortgage loans 251,336 2,759,417 3,010,753 285,371 2,733,929 3,019,300 Cost basis and fair value adjustments, net (12,939 ) 49,781 36,842 (12,705 ) 48,440 35,735 Allowance for loan losses for loans held for investment (26,510 ) (1,441 ) (27,951 ) (33,117 ) (2,424 ) (35,541 ) Total mortgage loans $ 211,887 $ 2,807,757 $ 3,019,644 $ 239,549 $ 2,779,945 $ 3,019,494 The following table displays the allowance for loan losses and recorded investment in our HFI loans, excluding loans for which we have elected the fair value option, by impairment or reserve methodology and portfolio segment. As of December 31, 2015 2014 Single-Family Multifamily Total Single-Family Multifamily Total (Dollars in millions) Allowance for loan losses by segment: Individually impaired loans (1) $ 25,437 $ 80 $ 25,517 $ 31,200 $ 175 $ 31,375 Collectively reserved loans 2,272 162 2,434 3,977 189 4,166 Total allowance for loan losses $ 27,709 $ 242 $ 27,951 $ 35,177 $ 364 $ 35,541 Recorded investment in loans by segment: Individually impaired loans (1) $ 171,161 $ 1,008 $ 172,169 $ 186,377 $ 1,809 $ 188,186 Collectively reserved loans 2,664,377 199,166 2,863,543 2,672,184 187,424 2,859,608 Total recorded investment in loans $ 2,835,538 $ 200,174 $ 3,035,712 $ 2,858,561 $ 189,233 $ 3,047,794 __________ (1) Includes acquired credit-impaired loans.
Aging Analysis [Table Text Block]	The following tables display an aging analysis of the total recorded investment in our HFI mortgage loans by portfolio segment and class, excluding loans for which we have elected the fair value option. As of December 31, 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 $ 29,154 $ 7,937 $ 26,346 $ 63,437 $ 2,598,756 $ 2,662,193 $ 46 $ 34,216 Government (2) 58 24 291 373 40,461 40,834 291 — Alt-A 4,085 1,272 6,141 11,498 84,603 96,101 6 7,407 Other 1,494 484 2,160 4,138 32,272 36,410 6 2,632 Total single-family 34,791 9,717 34,938 79,446 2,756,092 2,835,538 349 44,255 Multifamily (3) 23 N/A 123 146 200,028 200,174 — 591 Total $ 34,814 $ 9,717 $ 35,061 $ 79,592 $ 2,956,120 $ 3,035,712 $ 349 $ 44,846 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 NA 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 December 31, 2015 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 (1) (Dollars in millions) Individually impaired loans: With related allowance recorded: Single-family: Primary $ 116,477 $ 110,502 $ 16,745 $ 125,960 $ 120,221 $ 20,327 $ 309 Government 322 327 59 281 285 46 12 Alt-A 31,888 29,103 6,217 35,492 32,816 7,778 136 Other 12,893 12,179 2,416 14,667 13,947 3,049 38 Total single-family 161,580 152,111 25,437 176,400 167,269 31,200 495 Multifamily 650 654 80 1,230 1,241 175 6 Total individually impaired loans with related allowance recorded 162,230 152,765 25,517 177,630 168,510 31,375 501 With no related allowance recorded: (2) Single-family: Primary 15,891 14,725 — 16,704 14,876 — — Government 58 54 — 61 57 — — Alt-A 3,721 3,169 — 3,993 3,119 — — Other 1,222 1,102 — 1,240 1,056 — — Total single-family 20,892 19,050 — 21,998 19,108 — — Multifamily 353 354 — 565 568 — — Total individually impaired loans with no related allowance recorded 21,245 19,404 — 22,563 19,676 — — Total individually impaired loans (3) $ 183,475 $ 172,169 $ 25,517 $ 200,193 $ 188,186 $ 31,375 $ 501 For the Year Ended December 31, 2015 2014 2013 Average Recorded Investment Total Interest Income Recognized (4) Interest Income Recognized on a Cash Basis Average Recorded Investment Total Interest Income Recognized (4) Interest Income Recognized on a Cash Basis Average Recorded Investment Total Interest Income Recognized (4) Interest Income Recognized on a Cash Basis (Dollars in millions) Individually impaired loans: With related allowance recorded: Single-family: Primary $ 114,737 $ 4,190 $ 318 $ 121,926 $ 4,321 $ 494 $ 124,659 $ 4,351 $ 603 Government 299 12 — 270 13 — 213 11 — Alt-A 30,453 1,034 54 33,676 1,066 100 35,075 1,096 135 Other 12,863 376 21 14,490 402 36 15,537 425 52 Total single-family 158,352 5,612 393 170,362 5,802 630 175,484 5,883 790 Multifamily 973 16 — 1,699 80 1 2,552 128 1 Total individually impaired loans with related allowance recorded 159,325 5,628 393 172,061 5,882 631 178,036 6,011 791 With no related allowance recorded: (2) Single-family: Primary 15,796 1,039 91 13,852 864 215 11,442 1,369 227 Government 55 4 — 67 5 — 112 8 — Alt-A 3,647 218 11 2,799 189 47 2,207 329 45 Other 1,259 75 3 974 56 12 752 117 17 Total single-family 20,757 1,336 105 17,692 1,114 274 14,513 1,823 289 Multifamily 442 10 — 1,472 64 — 1,863 97 3 Total individually impaired loans with no related allowance recorded 21,199 1,346 105 19,164 1,178 274 16,376 1,920 292 Total individually impaired loans (3) $ 180,524 $ 6,974 $ 498 $ 191,225 $ 7,060 $ 905 $ 194,412 $ 7,931 $ 1,083 __________ (1) Effective January 1, 2015, we charged off accrued interest receivable associated with loans on nonaccrual status in connection with our adoption of a change in accounting policy related to the treatment of interest previously accrued, but not collected, at the date that loans are placed on nonaccrual status. See “ Note 1, Summary of Significant Accounting Policies ” for additional information. (2) The discounted cash flows or collateral value equals or exceeds the carrying value of the loan and, as such, no valuation allowance is required. (3) Includes single-family loans restructured in a TDR with a recorded investment of $170.3 billion , $185.2 billion and $187.6 billion as of December 31, 2015 , 2014 and 2013 , respectively. Includes multifamily loans restructured in a TDR with a recorded investment of $451 million , $716 million and $911 million as of December 31, 2015 , 2014 and 2013 , respectively. (4) Total single-family interest income recognized of $6.9 billion for the year ended December 31, 2015 consists of $5.7 billion of contractual interest and $1.2 billion of effective yield adjustments. Total single-family interest income recognized of $6.9 billion for the year ended December 31, 2014 consists of $5.8 billion of contractual interest and $1.1 billion of effective yield adjustments. Total single-family interest income recognized of $7.7 billion for the year ended December 31, 2013 consists of $5.7 billion of contractual interest and $2.0 billion of effective yield adjustments.
Troubled Debt Restructurings Activity [Table Text Block]	The following table displays the number of loans and recorded investment in loans restructured in a TDR. For the Year Ended December 31, 2015 2014 2013 Number of Loans Recorded Investment Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 71,293 $ 9,713 100,956 $ 14,301 126,998 $ 19,016 Government 241 27 365 47 312 35 Alt-A 9,037 1,374 14,715 2,441 21,471 3,794 Other 1,835 333 3,357 686 6,226 1,378 Total single-family 82,406 11,447 119,393 17,475 155,007 24,223 Multifamily 12 40 19 853 33 213 Total TDRs 82,418 $ 11,487 119,412 $ 18,328 155,040 $ 24,436 The following table displays 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 Year Ended December 31, 2015 2014 2013 Number of Loans Recorded Investment Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 26,206 $ 3,808 33,853 $ 5,095 45,539 $ 6,978 Government 118 16 124 15 130 17 Alt-A 4,128 706 5,392 960 9,601 1,732 Other 1,229 247 1,738 387 3,093 685 Total single-family 31,681 4,777 41,107 6,457 58,363 9,412 Multifamily 3 6 9 42 9 64 Total TDRs that subsequently defaulted 31,684 $ 4,783 41,116 $ 6,499 58,372 $ 9,476
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 December 31, 2015 (1) 2014 (1) Primary Alt-A Other Primary Alt-A Other (Dollars in millions) Estimated mark-to-market LTV ratio: (2) Less than or equal to 80% $ 2,228,533 $ 59,000 $ 21,274 $ 2,156,165 $ 60,851 $ 22,558 Greater than 80% and less than or equal to 90% 250,373 12,588 4,936 261,709 15,151 6,046 Greater than 90% and less than or equal to 100% 122,939 9,345 3,861 140,778 12,490 5,236 Greater than 100% and less than or equal to 110% 27,875 6,231 2,596 43,014 8,998 3,900 Greater than 110% and less than or equal to 120% 14,625 3,730 1,592 23,439 6,033 2,615 Greater than 120% and less than or equal to 125% 4,520 1,260 545 7,529 2,114 904 Greater than 125% 13,328 3,947 1,606 23,586 7,124 3,000 Total $ 2,662,193 $ 96,101 $ 36,410 $ 2,656,220 $ 112,761 $ 44,259 __________ (1) Excludes $40.8 billion and $45.3 billion as of December 31, 2015 and 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 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 December 31, 2015 2014 (Dollars in millions) Credit risk profile by internally assigned grade: (1) Pass $ 194,132 $ 182,079 Special Mention 3,202 3,070 Substandard 2,833 3,842 Doubtful 7 242 Total $ 200,174 $ 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)	12 Months Ended
	Dec. 31, 2015
Loans and Leases Receivable, Allowance [Abstract]
Allowance for Loan Losses Roll Forward by Segment [Table Text Block]	The following table displays changes in single-family, multifamily and total allowance for loan losses. For the Year Ended December 31, 2015 2014 2013 Of Fannie Mae Of Consolidated Trusts Total 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 $ 49,848 $ 7,839 $ 57,687 Provision (benefit) for loan losses (1) (258 ) 190 (68 ) (4,334 ) 553 (3,781 ) (6,751 ) (2,145 ) (8,896 ) Charge-offs (2)(3) (9,647 ) (84 ) (9,731 ) (6,168 ) (225 ) (6,393 ) (8,458 ) (256 ) (8,714 ) Recoveries 1,120 16 1,136 1,190 250 1,440 2,115 511 2,626 Transfers (4) 1,123 (1,123 ) — 1,513 (1,513 ) — 2,932 (2,932 ) — Other (5) 1,145 50 1,195 553 51 604 516 88 604 Ending balance $ 26,439 $ 1,270 $ 27,709 $ 32,956 $ 2,221 $ 35,177 $ 40,202 $ 3,105 $ 43,307 Multifamily allowance for loan losses: Beginning balance $ 161 $ 203 $ 364 $ 319 $ 220 $ 539 $ 671 $ 437 $ 1,108 Benefit for loan losses (1) (63 ) (27 ) (90 ) (91 ) (13 ) (104 ) (233 ) (187 ) (420 ) Charge-offs (2)(3) (40 ) (3 ) (43 ) (76 ) — (76 ) (153 ) — (153 ) Recoveries 4 — 4 — — — — — — Transfers (4) 4 (4 ) — 4 (4 ) — 30 (30 ) — Other (5) 5 2 7 5 — 5 4 — 4 Ending balance $ 71 $ 171 $ 242 $ 161 $ 203 $ 364 $ 319 $ 220 $ 539 Total allowance for loan losses: Beginning balance $ 33,117 $ 2,424 $ 35,541 $ 40,521 $ 3,325 $ 43,846 $ 50,519 $ 8,276 $ 58,795 Provision (benefit) for loan losses (1) (321 ) 163 (158 ) (4,425 ) 540 (3,885 ) (6,984 ) (2,332 ) (9,316 ) Charge-offs (2)(3) (9,687 ) (87 ) (9,774 ) (6,244 ) (225 ) (6,469 ) (8,611 ) (256 ) (8,867 ) Recoveries 1,124 16 1,140 1,190 250 1,440 2,115 511 2,626 Transfers (4) 1,127 (1,127 ) — 1,517 (1,517 ) — 2,962 (2,962 ) — Other (5) 1,150 52 1,202 558 51 609 520 88 608 Ending balance $ 26,510 $ 1,441 $ 27,951 $ 33,117 $ 2,424 $ 35,541 $ 40,521 $ 3,325 $ 43,846 __________ (1) Provision (benefit) for loan losses is included in “Benefit for credit losses” in our 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, for the year ended December 31, 2015 , charge-offs of (1) $1.8 billion in loans held for investment 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 in connection with our adoption of a change in accounting policy 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. (4) Includes transfers from trusts for delinquent loan purchases. (5) Amounts represent changes in other loss reserves which are reflected in provision (benefit) for loan losses, charge-offs, and recoveries.
Allowance for Loan Losses and Total Recorded Investment in HFI Loans [Table Text Block]	The following table displays the carrying value of our mortgage loans. As of December 31, 2015 2014 Of Fannie Mae Of Consolidated Trusts Total Of Fannie Mae Of Consolidated Trusts Total (Dollars in millions) Single-family $ 238,237 $ 2,574,174 $ 2,812,411 $ 262,116 $ 2,569,884 $ 2,832,000 Multifamily 13,099 185,243 198,342 23,255 164,045 187,300 Total unpaid principal balance of mortgage loans 251,336 2,759,417 3,010,753 285,371 2,733,929 3,019,300 Cost basis and fair value adjustments, net (12,939 ) 49,781 36,842 (12,705 ) 48,440 35,735 Allowance for loan losses for loans held for investment (26,510 ) (1,441 ) (27,951 ) (33,117 ) (2,424 ) (35,541 ) Total mortgage loans $ 211,887 $ 2,807,757 $ 3,019,644 $ 239,549 $ 2,779,945 $ 3,019,494 The following table displays the allowance for loan losses and recorded investment in our HFI loans, excluding loans for which we have elected the fair value option, by impairment or reserve methodology and portfolio segment. As of December 31, 2015 2014 Single-Family Multifamily Total Single-Family Multifamily Total (Dollars in millions) Allowance for loan losses by segment: Individually impaired loans (1) $ 25,437 $ 80 $ 25,517 $ 31,200 $ 175 $ 31,375 Collectively reserved loans 2,272 162 2,434 3,977 189 4,166 Total allowance for loan losses $ 27,709 $ 242 $ 27,951 $ 35,177 $ 364 $ 35,541 Recorded investment in loans by segment: Individually impaired loans (1) $ 171,161 $ 1,008 $ 172,169 $ 186,377 $ 1,809 $ 188,186 Collectively reserved loans 2,664,377 199,166 2,863,543 2,672,184 187,424 2,859,608 Total recorded investment in loans $ 2,835,538 $ 200,174 $ 3,035,712 $ 2,858,561 $ 189,233 $ 3,047,794 __________ (1) Includes acquired credit-impaired loans.

Investments in Securities (Tabl

Investments in Securities (Tables)	12 Months Ended
	Dec. 31, 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 December 31, 2015 2014 (Dollars in millions) Mortgage-related securities: Fannie Mae $ 4,813 $ 4,940 Freddie Mac 1,314 1,369 Ginnie Mae 426 166 Alt-A private-label securities 436 920 Subprime private-label securities 644 1,307 Commercial mortgage-backed securities (“CMBS”) 2,341 2,515 Mortgage revenue bonds 449 722 Other mortgage-related securities — 99 Total mortgage-related securities 10,423 12,038 U.S. Treasury securities 29,485 19,466 Total trading securities $ 39,908 $ 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 Year Ended December 31, 2015 2014 2013 (Dollars in millions) Net trading gains (losses) $ (368 ) $ 485 $ 260 Net trading gains (losses) recognized in the period related to securities still held at period end (453 ) 420 297
Schedule of Available-for-sale Securities Realized Gain (Loss) [Table Text Block]	The following table displays the gross realized gains, losses and proceeds on sales of AFS securities. For the Year Ended December 31, 2015 2014 2013 (Dollars in millions) Gross realized gains $ 1,066 $ 569 $ 1,632 Gross realized losses 70 5 979 Total proceeds (excludes initial sale of securities from new portfolio securitizations) 8,023 3,265 15,157
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 in our retained mortgage portfolio. As of December 31, 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 $ 4,008 $ 243 $ — $ (30 ) $ 4,221 Freddie Mac 4,000 299 — — 4,299 Ginnie Mae 343 48 — — 391 Alt-A private-label securities 2,029 653 (4 ) — 2,678 Subprime private-label securities 2,526 759 — (4 ) 3,281 CMBS 1,235 20 — — 1,255 Mortgage revenue bonds 2,639 99 (29 ) (8 ) 2,701 Other mortgage-related securities 1,361 49 (6 ) — 1,404 Total $ 18,141 $ 2,170 $ (39 ) $ (42 ) $ 20,230 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 s __________ (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 consolidated statements of operations and comprehensive income. (2) Represents the noncredit component of OTTI losses recorded in “Accumulated other comprehensive income” in our 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 December 31, 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 $ (8 ) $ 659 $ (22 ) $ 491 Alt-A private-label securities (1 ) 26 (3 ) 54 Subprime private-label securities — 12 (4 ) 91 Mortgage revenue bonds (35 ) 631 (2 ) 22 Other mortgage-related securities (6 ) 224 — — Total $ (50 ) $ 1,552 $ (31 ) $ 658 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 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 December 31, 2015 Alt-A Subprime Option ARM Fixed Rate Variable Rate Hybrid Rate (Dollars in millions) Unpaid principal balance $ 4,367 $ 434 $ 817 $ 805 $ 987 Weighted average collateral default (1) 41.2 % 28.2 % 12.0 % 20.4 % 8.6 % Weighted average collateral severities (2) 58.8 34.4 45.0 37.3 33.1 Weighted average voluntary prepayment rates (3) 2.7 7.5 11.6 8.7 12.5 Average credit enhancement (4) 18.2 3.6 7.2 8.7 4.3 __________ (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 consolidated statements of operations and comprehensive income. For the Year Ended December 31, 2015 2014 (Dollars in millions) Balance, beginning of period $ 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 8 58 Reductions for securities no longer in portfolio at period end (1,171 ) (904 ) 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 (1,492 ) (1,453 ) Reductions for amortization resulting from changes in cash flows expected to be collected over the remaining life of the securities (184 ) (346 ) Balance, end of period $ 2,421 $ 5,260
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 December 31, 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 $ 4,008 $ 4,221 $ — $ — $ 160 $ 164 $ 114 $ 123 $ 3,734 $ 3,934 Freddie Mac 4,000 4,299 1 1 185 192 310 337 3,504 3,769 Ginnie Mae 343 391 — — 1 1 61 68 281 322 Alt-A private-label securities 2,029 2,678 — — — — — — 2,029 2,678 Subprime private-label securities 2,526 3,281 — — — — — — 2,526 3,281 CMBS 1,235 1,255 278 280 899 917 — — 58 58 Mortgage revenue bonds 2,639 2,701 11 11 112 113 202 205 2,314 2,372 Other mortgage-related securities 1,361 1,404 — — — — 29 30 1,332 1,374 Total $ 18,141 $ 20,230 $ 290 $ 292 $ 1,357 $ 1,387 $ 716 $ 763 $ 15,778 $ 17,788 Weighted average yield (1) 4.94 % 4.36 % 4.51 % 6.28 % 4.93 % __________ (1) Yields are determined by dividing interest income (including amortization and accretion of premiums, discounts and other cost basis adjustments) by amortized cost balances as of year-end. Yields on tax-exempt obligations have been computed on a tax equivalent basis.

Financial Guarantees (Tables)

Financial Guarantees (Tables)	12 Months Ended
	Dec. 31, 2015
Guarantees [Abstract]
Financial Guarantees and Maximum Recovery [Table Text Block]	The following table displays our maximum exposure, guaranty obligation recognized in our consolidated balance sheets and the maximum potential recovery from third parties through available credit enhancements and recourse related to our financial guarantees. As of December 31, 2015 2014 Maximum Exposure (1) Guaranty Obligation Maximum Recovery (2) Maximum Exposure (1) Guaranty Obligation Maximum Recovery (2) (Dollars in millions) Unconsolidated Fannie Mae MBS $ 15,069 $ 194 $ 8,857 $ 17,184 $ 214 $ 9,775 Other guaranty arrangements (3) 16,504 135 2,869 18,781 168 4,447 Total $ 31,573 $ 329 $ 11,726 $ 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 and financial guarantors, see “ Note 15, 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)	12 Months Ended
	Dec. 31, 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 related valuation allowance. For the Year Ended December 31, 2015 2014 2013 (Dollars in millions) Beginning balance — Acquired property $ 11,442 $ 12,307 $ 11,158 Additions 9,382 13,100 16,092 Disposals (13,343 ) (13,965 ) (14,943 ) Ending balance — Acquired property 7,481 11,442 12,307 Beginning balance — Valuation allowance (824 ) (686 ) (669 ) Decrease (increase) in valuation allowance 109 (138 ) (17 ) Ending balance — Valuation allowance (715 ) (824 ) (686 ) Ending balance — Acquired property, net $ 6,766 $ 10,618 $ 11,621

Short-Term Borrowings and Lon45

Short-Term Borrowings and Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 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 December 31, 2015 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) $ 62 — % $ 50 — % Short-term debt of Fannie Mae $ 71,007 0.26 % $ 105,012 0.11 % Debt of consolidated trusts 943 0.19 1,560 0.09 Total short-term debt $ 71,950 0.26 % $ 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 December 31, 2015 2014 Maturities Outstanding Weighted- Average Interest Rate (1) Maturities Outstanding Weighted- Average Interest Rate (1) (Dollars in millions) Senior fixed: Benchmark notes and bonds 2016 - 2030 $ 154,057 2.49 % 2015 - 2030 $ 173,010 2.41 % Medium-term notes (2) 2016 - 2025 96,997 1.53 2015 - 2024 114,556 1.42 Other (3) 2016 - 2038 27,772 4.88 2015 - 2038 32,941 4.65 Total senior fixed 278,826 2.39 320,507 2.29 Senior floating: Medium-term notes (2) 2016 - 2019 20,791 0.27 2015 - 2019 24,469 0.15 Connecticut Avenue Securities (4) 2023 - 2028 10,764 3.84 2023 - 2024 6,041 2.97 Other (5) 2020 - 2037 368 10.46 2020 - 2037 363 8.71 Total senior floating 31,923 1.58 30,873 0.81 Subordinated debentures 2019 4,227 9.93 2019 3,849 9.93 Secured borrowings (6) 2021 - 2022 152 1.47 2021 - 2022 202 1.90 Total long-term debt of Fannie Mae (7) 315,128 2.41 355,431 2.24 Debt of consolidated trusts 2016 - 2054 2,810,593 2.94 2015 - 2054 2,760,152 3.02 Total long-term debt $ 3,125,721 2.88 % $ 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) Includes other long-term debt and foreign exchange bonds. (4) 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. (5) Consists of structured debt instruments that are reported at fair value. (6) Represents our remaining liability resulting from the transfer of financial assets from our consolidated balance sheets that did not qualify as a sale under the accounting guidance for the transfer of financial instruments. (7) Includes unamortized discounts and premiums, other cost basis adjustments and fair value adjustments of $3.2 billion and $4.1 billion as of December 31, 2015 and 2014 , respectively.
Long-Term Debt by Year of Maturity [Table Text Block]	The following table displays the amount of our long-term debt as of December 31, 2015 by year of maturity for each of the years 2016 through 2020 and thereafter. The first column assumes that we pay off this debt at maturity or on the call date if the call has been announced, while the second column assumes that we redeem our callable debt at the next available call date. Long-Term Debt by Year of Maturity Assuming Callable Debt Redeemed at Next Available Call Date (Dollars in millions) 2016 $ 52,829 $ 143,970 2017 76,970 69,351 2018 60,555 32,832 2019 29,656 19,036 2020 30,129 16,658 Thereafter 64,989 33,281 Total debt of Fannie Mae (1) 315,128 315,128 Debt of consolidated trusts (2) 2,810,593 2,810,593 Total long-term debt $ 3,125,721 $ 3,125,721 __________ (1) Includes unamortized discounts and premiums, other cost basis adjustments and fair value adjustments of $3.2 billion . (2) Contractual maturity of debt of consolidated trusts is not a reliable indicator of expected maturity because borrowers of the underlying loans generally have the right to prepay their obligations at any time.

Derivative Instruments (Tables)

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 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 December 31, 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 $ 33,154 $ 267 $ 123,106 $ (6,920 ) $ 41,965 $ 733 $ 123,557 $ (7,125 ) Receive-fixed 59,796 3,436 143,209 (753 ) 67,629 4,486 157,272 (1,302 ) Basis 1,864 141 17,100 (15 ) 5,769 123 7,100 (2 ) Foreign currency 295 95 258 (52 ) 344 144 273 (30 ) Swaptions: Pay-fixed 7,050 45 14,950 (26 ) 11,100 57 26,525 (175 ) Receive-fixed 2,000 8 13,950 (171 ) 750 96 29,525 (816 ) Other (1) 9,196 28 — (2 ) 1,071 28 12 (1 ) Total gross risk management derivatives 113,355 4,020 312,573 (7,939 ) 128,628 5,667 344,264 (9,451 ) Accrued interest receivable (payable) — 758 — (977 ) — 749 — (1,013 ) Netting adjustment (2) — (4,024 ) — 8,650 — (5,186 ) — 10,194 Total net risk management derivatives $ 113,355 $ 754 $ 312,573 $ (266 ) $ 128,628 $ 1,230 $ 344,264 $ (270 ) Mortgage commitment derivatives: Mortgage commitments to purchase whole loans $ 4,815 $ 9 $ 2,960 $ (9 ) $ 6,157 $ 28 $ 428 $ — Forward contracts to purchase mortgage-related securities 31,273 66 19,418 (57 ) 43,533 223 6,112 (8 ) Forward contracts to sell mortgage-related securities 26,224 65 40,753 (92 ) 4,886 4 57,910 (336 ) Total mortgage commitment derivatives 62,312 140 63,131 (158 ) 54,576 255 64,450 (344 ) Derivatives at fair value $ 175,667 $ 894 $ 375,704 $ (424 ) $ 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 $4.9 billion and $5.3 billion as of December 31, 2015 and 2014 , respectively. Cash collateral received was $314 million and $245 million as of December 31, 2015 and 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 Year Ended December 31, 2015 2014 2013 (Dollars in millions) Risk management derivatives: Swaps: Pay-fixed $ (746 ) $ (7,703 ) $ 14,393 Receive-fixed 625 4,229 (10,721 ) Basis 4 85 (115 ) Foreign currency (60 ) 27 (101 ) Swaptions: Pay-fixed 135 (4 ) (238 ) Receive-fixed (93 ) (197 ) 307 Other (25 ) 1 21 Accrual of periodic settlements: Pay-fixed interest-rate swaps (3,602 ) (3,712 ) (4,463 ) Receive-fixed interest-rate swaps 2,603 2,600 3,632 Other 39 50 64 Total risk management derivatives fair value gains (losses), net (1,120 ) (4,624 ) 2,779 Mortgage commitment derivatives fair value gains (losses), net (393 ) (1,140 ) 501 Total derivatives fair value gains (losses), net $ (1,513 ) $ (5,764 ) $ 3,280

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	The following table displays the components of our provision (benefit) for federal income taxes. For the Year Ended December 31, 2015 2014 2013 (Dollars in millions) Current income tax provision (benefit) $ (271 ) $ 1,879 $ 3,067 Deferred income tax provision (benefit) (1) 5,524 5,062 (48,482 ) Provision (benefit) for federal income taxes $ 5,253 $ 6,941 $ (45,415 ) __________ (1) Amount excludes the income tax effect of items recognized directly in “Fannie Mae stockholders’ equity.”
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	The following table displays the difference between our effective tax rate and the statutory federal tax rate. For the Year Ended December 31, 2015 2014 2013 Statutory corporate tax rate 35.0 % 35.0 % 35.0 % Equity investments in affordable housing projects (2.6 ) (1.8 ) (1.5 ) Other 0.9 1.4 — Valuation allowance (0.9 ) (1.8 ) (151.3 ) Effective tax rate 32.4 % 32.8 % (117.8 ) %
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	The following table displays our deferred tax assets, deferred tax liabilities and valuation allowance. As of December 31, 2015 2014 (Dollars in millions) Deferred tax assets: Mortgage and mortgage-related assets $ 16,956 $ 16,250 Allowance for loan losses and basis in acquired property, net 11,760 17,435 Debt and derivative instruments 3,512 4,254 Partnership credits 3,402 2,918 Partnership and other equity investments 745 934 Other, net 1,543 1,699 Total deferred tax assets 37,918 43,490 Deferred tax liabilities: Unrealized gains on AFS securities, net 731 1,134 Total deferred tax liabilities 731 1,134 Valuation allowance — (150 ) Deferred tax assets, net $ 37,187 $ 42,206
Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]	The following table displays the changes in our unrecognized tax benefits. For the Year Ended December 31, 2015 2014 2013 (Dollars in millions) Unrecognized tax benefits as of January 1 $ 213 $ 514 $ 648 Gross decreases—tax positions in prior years (213 ) (301 ) (134 ) Unrecognized tax benefits as of December 31 (1) $ — $ 213 $ 514 __________ (1) Amounts exclude tax credits of $91 million and $220 million as of December 31, 2014 and 2013, respectively.

Loss Per Share (Tables)

Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 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 loss per share of common stock. For the Year Ended December 31, 2015 2014 2013 (Dollars and shares in millions, except per share amounts) Net income $ 10,955 $ 14,209 $ 83,982 Less: Net income attributable to noncontrolling interest (1 ) (1 ) (19 ) Net income attributable to Fannie Mae 10,954 14,208 83,963 Dividends distributed or available for distribution to senior preferred stockholder (1) (11,216 ) (15,323 ) (85,419 ) Net loss attributable to common stockholders $ (262 ) $ (1,115 ) $ (1,456 ) Weighted-average common shares outstanding—basic and diluted (2) 5,762 5,762 5,762 Loss per share: basic and diluted $ (0.05 ) $ (0.19 ) $ (0.25 ) __________ (1) Dividends distributed or available for distribution were calculated based on our net worth as of the end of the fiscal quarters for each respective year, less the applicable capital reserve. See “Note 1, Summary of Significant Accounting Policies” for additional information on our senior preferred stock agreement and our payment of dividends to Treasury. (2) Includes 4.6 billion for the years ended December 31, 2015, 2014 and 2013, 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 December 31, 2015, 2014 and 2013, respectively.

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Segment results [Table Text Block]	For the Year Ended December 31, 2015 Business Segments Single-Family Multifamily Capital Markets Reconciling Items (1) Total (Dollars in millions) Net interest income (loss) $ 184 $ (92 ) $ 5,828 $ 15,489 (2) $ 21,409 Benefit for credit losses 688 107 — — 795 Net interest income after benefit for credit losses 872 15 5,828 15,489 22,204 Guaranty fee income (expense) (3) 12,476 1,439 (863 ) (12,924 ) (4) 128 (4) Investment gains (losses), net (2 ) 33 5,539 (4,234 ) (5) 1,336 Fair value gains (losses), net (11 ) — (2,049 ) 293 (6) (1,767 ) Debt extinguishment gains (losses), net (7) — — (37 ) 45 8 Gains (losses) from partnership investments (7) (39 ) 282 — 1 244 Fee and other income 666 265 209 80 1,220 Administrative expenses (2,053 ) (361 ) (636 ) — (3,050 ) Foreclosed property income (expense) (1,723 ) 94 — — (1,629 ) TCCA fees (3) (1,621 ) — — — (1,621 ) Other income (expense) (942 ) (13 ) 8 82 (865 ) Income before federal income taxes 7,623 1,754 7,999 (1,168 ) 16,208 Provision for federal income taxes (2,491 ) (247 ) (2,515 ) — (5,253 ) Net income 5,132 1,507 5,484 (1,168 ) 10,955 Less: Net income attributable to noncontrolling interest — — — (1 ) (8) (1 ) Net income attributable to Fannie Mae $ 5,132 $ 1,507 $ 5,484 $ (1,169 ) $ 10,954 For the Year Ended December 31, 2014 Business Segments Single-Family Multifamily Capital Markets Reconciling Items (1) Total (Dollars in millions) Net interest income (loss) $ 6 $ (79 ) $ 7,243 $ 12,798 (2) $ 19,968 Benefit for credit losses 3,850 114 — — 3,964 Net interest income after benefit for credit losses 3,856 35 7,243 12,798 23,932 Guaranty fee income (expense) (3) 11,702 1,297 (955 ) (11,869 ) (4) 175 (4) Investment gains (losses), net (1 ) 57 6,378 (5,498 ) (5) 936 Fair value gains (losses), net (19 ) — (5,476 ) 662 (6) (4,833 ) Debt extinguishment gains, net (7) — — 35 31 66 Gains (losses) from partnership investments (7) (31 ) 299 — 1 269 Fee and other income 624 166 4,894 28 5,712 Administrative expenses (1,830 ) (306 ) (641 ) — (2,777 ) Foreclosed property income (expense) (225 ) 83 — — (142 ) TCCA fees (3) (1,375 ) — — — (1,375 ) Other income (expense) (726 ) (10 ) (77 ) — (813 ) Income before federal income taxes 11,975 1,621 11,401 (3,847 ) 21,150 Provision for federal income taxes (3,496 ) (158 ) (3,287 ) — (6,941 ) Net income 8,479 1,463 8,114 (3,847 ) 14,209 Less: Net income attributable to noncontrolling interest — — — (1 ) (8) (1 ) Net income attributable to Fannie Mae $ 8,479 $ 1,463 $ 8,114 $ (3,848 ) $ 14,208 For the Year Ended December 31, 2013 Business Segments Single-Family Multifamily Capital Markets Reconciling Items (1) Total (Dollars in millions) Net interest income (loss) $ 205 $ (74 ) $ 9,764 $ 12,509 (2) $ 22,404 Benefit for credit losses 8,469 480 — — 8,949 Net interest income after benefit for credit losses 8,674 406 9,764 12,509 31,353 Guaranty fee income (expense) (3) 10,468 1,217 (1,115 ) (10,365 ) (4) 205 (4) Investment gains (losses), net 3 21 4,847 (3,744 ) (5) 1,127 Fair value gains (losses), net (10 ) — 3,148 (179 ) (6) 2,959 Debt extinguishment gains, net (7) — — 27 104 131 Gains from partnership investments (7) — 498 — 19 517 Fee and other income (expense) 630 182 3,010 (97 ) 3,725 Administrative expenses (1,706 ) (280 ) (559 ) — (2,545 ) Foreclosed property income 2,736 103 — — 2,839 TCCA fees (3) (1,001 ) — — — (1,001 ) Other income (expense) (628 ) (2 ) 20 (133 ) (743 ) Income before federal income taxes 19,166 2,145 19,142 (1,886 ) 38,567 Benefit for federal income taxes (9) 29,110 7,924 8,381 — 45,415 Net income 48,276 10,069 27,523 (1,886 ) 83,982 Less: Net loss attributable to noncontrolling interest — — — (19 ) (8) (19 ) Net income attributable to Fannie Mae $ 48,276 $ 10,069 $ 27,523 $ (1,905 ) $ 83,963 __________ (1) Represents activity related to the assets and liabilities of consolidated trusts in our consolidated balance sheets, and 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. (2) Represents net interest income of consolidated trusts and amortization expense of cost basis adjustments on securities in the Capital Markets group’s mortgage portfolio that on a GAAP basis are eliminated. (3) Reflects the impact of a 10 basis point guaranty fee increase implemented in 2012 pursuant to the TCCA, the incremental revenue from which is remitted to Treasury. The resulting revenue is included in guaranty fee income and the expense is recognized as “TCCA fees.” (4) Represents the guaranty fees paid from consolidated trusts to the Single-Family and Multifamily segments and 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 consolidated statements of operations and comprehensive income. (5) 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 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. (6) Represents the removal of fair value adjustments on consolidated Fannie Mae MBS classified as trading that are in the Capital Markets group’s mortgage portfolio. (7) Debt extinguishment gains, net and gains (losses) from partnership investments are included in other expenses in our consolidated statements of operations and comprehensive income. (8) Represents the adjustment from equity method accounting to consolidation accounting for partnership investments that are consolidated in our consolidated balance sheets. (9) Primarily represents the release of the valuation allowance for our deferred tax assets that generally are directly attributable to each segment based on the nature of the item.
Total assets by segment [Table Text Block]	The following table displays total assets by segment. As of December 31, 2015 2014 2013 (Dollars in millions) Single-Family $ 34,911 $ 43,512 $ 41,206 Multifamily 9,947 9,281 10,848 Capital Markets 432,689 510,848 596,436 Reconciling items (1) 2,744,370 2,684,535 2,621,618 Total assets $ 3,221,917 $ 3,248,176 $ 3,270,108 __________ (1) Includes assets of consolidated trusts of $2.8 trillion as of December 31, 2015, 2014 and 2013. Includes the elimination of Fannie Mae MBS in the Capital Markets group’s mortgage portfolio that are issued by consolidated trusts. Also includes the elimination of the allowance for loan losses and fair value losses previously recognized on acquired credit impaired loans as they are not treated as assets for Single-Family and Multifamily segment reporting purposes because these allowances and losses relate to loan assets that are held by the Capital Markets segment and consolidated trusts.

Equity (Tables)

Equity (Tables)	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Preferred Stock [Table Text Block]	Preferred Stock The following table displays our senior preferred stock and preferred stock outstanding. Issued and Outstanding as of December 31, Annual Dividend Rate as of December 31, 2015 2015 2014 Stated Value per Share Title Issue Date Shares Amount Shares Amount Redeemable on or After (Dollars and shares in millions, except per share amounts) Senior Preferred Stock Series 2008-2 September 8, 2008 1 $ 117,149 1 $ 117,149 $ 117,149 (1) N/A (2) N/A (3) Preferred Stock Series D September 30, 1998 3 $ 150 3 $ 150 $ 50 5.250 % September 30, 1999 Series E April 15, 1999 3 150 3 150 50 5.100 April 15, 2004 Series F March 20, 2000 14 690 14 690 50 0.260 (4) March 31, 2002 (5) Series G August 8, 2000 6 288 6 288 50 0.400 (6) September 30, 2002 (5) Series H April 6, 2001 8 400 8 400 50 5.810 April 6, 2006 Series I October 28, 2002 6 300 6 300 50 5.375 October 28, 2007 Series L April 29, 2003 7 345 7 345 50 5.125 April 29, 2008 Series M June 10, 2003 9 460 9 460 50 4.750 June 10, 2008 Series N September 25, 2003 5 225 5 225 50 5.500 September 25, 2008 Series O December 30, 2004 50 2,500 50 2,500 50 7.000 (7) December 31, 2007 Convertible Series 2004-I (8) December 30, 2004 — 2,492 — 2,492 100,000 5.375 January 5, 2008 Series P September 28, 2007 40 1,000 40 1,000 25 4.500 (9) September 30, 2012 Series Q October 4, 2007 15 375 15 375 25 6.750 September 30, 2010 Series R (10) November 21, 2007 21 530 21 530 25 7.625 November 21, 2012 Series S December 11, 2007 280 7,000 280 7,000 25 7.750 (11) December 31, 2010 (12) Series T (13) May 19, 2008 89 2,225 89 2,225 25 8.250 May 20, 2013 Total 556 $ 19,130 556 $ 19,130 __________ (1) Initial stated value per share was $1,000 . Based on our draws of funds under the senior preferred stock purchase agreement with Treasury, the stated value per share on December 31, 2015 was $117,149 . (2) For the dividend period ended December 31, 2015 , the dividend is calculated based on our net worth as of September 30, 2015, less the applicable capital reserve amount of $1.8 billion . The capital reserve amount is $1.2 billion for each dividend period in 2016. The applicable capital reserve amount will continue to be reduced by $600 million each year until it reaches zero on January 1, 2018. For each dividend period beginning in 2018, the dividend amount will be the entire amount of our net worth, if any, as of the end of the immediately preceding fiscal quarter. (3) Any liquidation preference of our senior preferred stock in excess of $1.0 billion may be repaid through an issuance of common or preferred stock, which would require the consent of the conservator and Treasury. The initial $1.0 billion liquidation preference may be repaid only in conjunction with termination of the senior preferred stock purchase agreement. (4) Rate effective March 31, 2014. Variable dividend rate resets every two years at a per annum rate equal to the two-year Constant Maturity U.S. Treasury Rate (“CMT”) minus 0.16% with a cap of 11% per year. (5) Represents initial call date. Redeemable every two years thereafter. (6) Rate effective September 30, 2014. Variable dividend rate resets every two years at a per annum rate equal to the two-year CMT rate minus 0.18% with a cap of 11% per year. (7) Rate effective December 31, 2015 . Variable dividend rate resets quarterly thereafter at a per annum rate equal to the greater of 7.00% or 10-year CMT rate plus 2.375% . (8) Issued and outstanding shares were 24,922 as of December 31, 2015 and 2014. (9) Rate effective December 31, 2015 . Variable dividend rate resets quarterly thereafter at a per annum rate equal to the greater of 4.50% or 3-Month LIBOR plus 0.75% . (10) On November 21, 2007, we issued 20 million shares of preferred stock in the amount of $500 million . Subsequent to the initial issuance, we issued an additional 1.2 million shares in the amount of $30 million on December 14, 2007 under the same terms as the initial issuance. (11) Rate effective December 31, 2015 . Variable dividend rate resets quarterly thereafter at a per annum rate equal to the greater of 7.75% or 3-Month LIBOR plus 4.23% . (12) Represents initial call date. Redeemable every five years thereafter. (13) On May 19, 2008, we issued 80 million shares of preferred stock in the amount of $2.0 billion . Subsequent to the initial issuance, we issued an additional 8 million shares in the amount of $200 million on May 22, 2008 and 1 million shares in the amount of $25 million on June 4, 2008 under the same terms as the initial issuance.
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	Accumulated Other Comprehensive Income The following table displays our accumulated other comprehensive income. As of December 31, 2015 2014 2013 (Dollars in millions) Net unrealized gains on AFS securities for which we have not recorded OTTI, net of tax $ 455 $ 592 $ 365 Net unrealized gains on AFS securities for which we have recorded OTTI, net of tax 903 1,529 1,262 Prior service credit (cost) and actuarial gains (losses), net of amortization, and other, net of tax 49 (388 ) (424 ) Accumulated other comprehensive income $ 1,407 $ 1,733 $ 1,203 The table below displays changes in accumulated other comprehensive income, net of tax. For the Year Ended December 31, 2015 2014 AFS Securities (1) Other (2) Total AFS Securities (1) Other Total (Dollars in millions) Beginning balance $ 2,121 $ (388 ) $ 1,733 $ 1,627 $ (424 ) $ 1,203 Other comprehensive income before reclassifications (280 ) 17 (263 ) 722 37 759 Amounts reclassified from other comprehensive income (483 ) 420 (63 ) (228 ) (1 ) (229 ) Net other comprehensive income (763 ) 437 (326 ) 494 36 530 Ending balance $ 1,358 $ 49 $ 1,407 $ 2,121 $ (388 ) $ 1,733 __________ (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 consolidated statements of operations and comprehensive income. (2) The amounts reclassified from AOCI includes a reclassification adjustment related to the termination of the defined benefit pension plans, which is recorded in “Administrative expenses” and “Benefit (provision) for federal income taxes,” in our consolidated statements of operations and comprehensive income.

Regulatory Capital Requiremen51

Regulatory Capital Requirements (Tables)	12 Months Ended
	Dec. 31, 2015
Regulatory Capital Requirements [Abstract]
Regulatory Capital Classification Measures [Table Text Block]	The following table displays our regulatory capital classification measures. As of December 31, 2015 2014 (Dollars in millions) Core capital (1) $ (114,526 ) $ (115,202 ) Statutory minimum capital requirement (2) 25,144 27,044 Deficit of core capital over statutory minimum capital requirement $ (139,670 ) $ (142,246 ) __________ (1) The sum of (a) the stated value of our outstanding common stock (common stock less treasury stock); (b) the stated value of our outstanding non-cumulative perpetual preferred stock; (c) our paid-in capital; and (d) our retained earnings (accumulated deficit). Core capital does not include: (a) accumulated other comprehensive income or (b) senior preferred stock. (2) Generally, the sum of (a) 2.50% of on-balance sheet assets, except those underlying Fannie Mae MBS held by third parties; (b) 0.45% of the unpaid principal balance of outstanding Fannie Mae MBS held by third parties; and (c) up to 0.45% of other off-balance sheet obligations, which may be adjusted by the Director of FHFA under certain circumstances.

Concentrations of Credit Risk (

Concentrations of Credit Risk (Tables)	12 Months Ended
	Dec. 31, 2015
Geographic Concentration Risk [Member]
Concentration Risk [Line Items]
Schedules of Concentration of Risk, by Risk Factor [Table Text Block]	The following table displays the regional geographic concentration of single-family and multifamily loans in our guaranty book of business. Geographic Concentration (1) Percentage of Single-Family Conventional Guaranty Book of Business (2) Percentage of Multifamily Guaranty Book of Business (3) As of December 31, As of December 31, 2015 2014 2015 2014 Midwest 15 % 15 % 9 % 9 % Northeast 19 19 17 18 Southeast 22 22 23 22 Southwest 16 16 21 20 West 28 28 30 31 Total 100 % 100 % 100 % 100 % __________ (1) Midwest consists of IL, IN, IA, MI, MN, NE, ND, OH, SD, WI; Northeast consists of CT, DE, ME, MA, NH, NJ, NY, PA, PR, RI, VT, VI; Southeast consists of AL, DC, FL, GA, KY, MD, MS, NC, SC, TN, VA, WV; Southwest consists of AZ, AR, CO, KS, LA, MO, NM, OK, TX, UT; West consists of AK, CA, GU, HI, ID, MT, NV, OR, WA and WY. (2) Consists of the portion of our single-family conventional guaranty book of business for which we have detailed loan level information, which constituted over 99% of our total single-family conventional guaranty book of business as of December 31, 2015 and 2014. (3) Consists of the portion of our multifamily guaranty book of business for which we have detailed loan level information, which constituted 99% of our total multifamily guaranty book of business as of December 31, 2015 and 2014.
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 December 31, 2015 (1) 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) 1.27 % 0.37 % 1.59 % 1.27 % 0.38 % 1.99 % Percentage of single-family conventional loans (4) 1.46 0.41 1.55 1.47 0.43 1.89
Schedule of Risk Characteristics Guaranty Book of Business [Table Text Block]	As of December 31, 2015 (1) 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 % 10.76 % 5 % 10.98 % Geographical distribution: California 20 0.58 20 0.70 Florida 6 2.86 6 4.42 New Jersey 4 4.87 4 5.78 New York 5 3.55 5 4.17 All other states 65 1.34 65 1.57 Product distribution: Alt-A 4 6.53 4 7.77 Vintages: 2005 2 5.67 3 6.18 2006 3 8.49 3 9.61 2007 3 9.73 4 10.79 2008 2 5.84 2 6.27 All other vintages 90 0.77 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 December 31, 2015 and 2014 . (2) Consists of single-family conventional loans that were 90 days or more past due or in the foreclosure process as of December 31, 2015 and 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 December 31, 2015 (1)(2) 2014 (1)(2) 30 Days Delinquent Seriously Delinquent (3) 30 Days Delinquent Seriously Delinquent (3) Percentage of multifamily guaranty book of business 0.03 % 0.07 % 0.04 % 0.05 %
Schedule of Risk Characteristics Guaranty Book of Business [Table Text Block]	As of December 31, 2015 (1) 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 % 0.40 % 3 % 0.31 % Less than or equal to 80% 97 0.06 97 0.04 Current DSCR less than 1.0 (5) 2 1.51 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 December 31, 2015 and 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)	12 Months Ended
	Dec. 31, 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 consolidated balance sheets. As of December 31, 2015 Net Amount Presented in the Consolidated Balance Sheets Amounts Not Offset in the Consolidated Balance Sheets Gross Amount Gross Amount Offset (1) Financial Instruments (2) Collateral (3) Net Amount (Dollars in millions) Assets: OTC risk management derivatives $ 4,042 $ (4,021 ) $ 21 $ — $ (18 ) $ 3 Cleared risk management derivatives 708 (3 ) 705 — — 705 Mortgage commitment derivatives 140 — 140 (119 ) (3 ) 18 Total derivative assets 4,890 (4,024 ) 866 (4 ) (119 ) (21 ) 726 Securities purchased under agreements to resell or similar arrangements (5) 37,950 — 37,950 — (37,950 ) — Total assets $ 42,840 $ (4,024 ) $ 38,816 $ (119 ) $ (37,971 ) $ 726 Liabilities: OTC risk management derivatives $ (6,118 ) $ 5,861 $ (257 ) $ — $ — $ (257 ) Cleared risk management derivatives (2,796 ) 2,789 (7 ) — — (7 ) Mortgage commitment derivatives (158 ) — (158 ) 119 (1 ) (40 ) Total derivative liabilities (9,072 ) 8,650 (422 ) (4 ) 119 (1 ) (304 ) Securities sold under agreements to repurchase or similar arrangements (62 ) — (62 ) — 62 — Total liabilities $ (9,134 ) $ 8,650 $ (484 ) $ 119 $ 61 $ (304 ) As of December 31, 2014 Net Amount Presented in the Consolidated Balance Sheets Amounts Not Offset in the 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 consolidated balance sheets. (3) Represents collateral posted or received that has neither been recognized nor offset in our consolidated balance sheets. Does not include collateral held in excess of our exposure. The fair value of non-cash collateral accepted for OTC risk management derivatives was $37 million and $51 million as of December 31, 2015 and 2014, respectively. The fair value of non-cash collateral accepted for securities purchased under agreements to resell or similar arrangements was $38.0 billion and $47.6 billion , of which $36.2 billion and $41.9 billion could be sold or repledged as of December 31, 2015 and 2014, respectively. None of the underlying collateral was sold or repledged as of December 31, 2015 or 2014. The fair value of non-cash collateral we pledged for securities sold under agreements to repurchase was $62 million and $50 million as of December 31, 2015 and 2014, which the counterparty was permitted to sell or repledge. The fair value of non-cash collateral we pledged for cleared risk management derivatives was $135 million as of December 31, 2015 , which the counterparty was permitted to sell or repledge. (4) Excludes derivative assets of $28 million as of December 31, 2015 and 2014, and derivative liabilities of $2 million and $1 million recognized in our consolidated balance sheets as of December 31, 2015 and 2014, respectively, that are not subject to enforceable master netting arrangements. (5) Includes $10.6 billion and $16.6 billion of securities purchased under agreements to resell classified as “Cash and cash equivalents” in our consolidated balance sheets as of December 31, 2015 and 2014, respectively.

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Recurring Changes in Fair Value [Table Text Block]	The following tables display our assets and liabilities measured in our 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 December 31, 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 $ — $ 4,813 $ — $ — $ 4,813 Freddie Mac — 1,314 — — 1,314 Ginnie Mae — 426 — — 426 Alt-A private-label securities — 131 305 — 436 Subprime private-label securities — — 644 — 644 CMBS — 2,341 — — 2,341 Mortgage revenue bonds — — 449 — 449 Non-mortgage-related securities: U.S. Treasury securities 29,485 — — — 29,485 Total trading securities 29,485 9,025 1,398 — 39,908 Available-for-sale securities: Mortgage-related securities: Fannie Mae — 4,221 — — 4,221 Freddie Mac — 4,295 4 — 4,299 Ginnie Mae — 391 — — 391 Alt-A private-label securities — 1,637 1,041 — 2,678 Subprime private-label securities — — 3,281 — 3,281 CMBS — 1,255 — — 1,255 Mortgage revenue bonds — — 2,701 — 2,701 Other — — 1,404 — 1,404 Total available-for-sale securities — 11,799 8,431 — 20,230 Mortgage loans — 12,598 1,477 — 14,075 Other assets: Risk management derivatives: Swaps — 4,541 156 — 4,697 Swaptions — 53 — — 53 Other — — 28 — 28 Netting adjustment — — — (4,024 ) (4,024 ) Mortgage commitment derivatives — 135 5 — 140 Total other assets — 4,729 189 (4,024 ) 894 Total assets at fair value $ 29,485 $ 38,151 $ 11,495 $ (4,024 ) $ 75,107 Fair Value Measurements as of December 31, 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 $ — $ 10,764 $ 369 $ — $ 11,133 Total of Fannie Mae — 10,764 369 — 11,133 Of consolidated trusts — 23,113 496 — 23,609 Total long-term debt — 33,877 865 — 34,742 Other liabilities: Risk management derivatives: Swaps — 8,697 20 — 8,717 Swaptions — 197 — — 197 Other — — 2 — 2 Netting adjustment — — — (8,650 ) (8,650 ) Mortgage commitment derivatives — 148 10 — 158 Total other liabilities — 9,042 32 (8,650 ) 424 Total liabilities at fair value $ — $ 42,919 $ 897 $ (8,650 ) $ 35,166 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 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 Year Ended December 31, 2015 Total Gains (Losses) (Realized/Unrealized) Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of December 31, 2015 (5)(6) Balance, December 31, 2014 Included in Net Income Included in Total Other Comprehensive Income (Loss) (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 (4) Transfers into Level 3 (4) Balance, December 31, 2015 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 305 $ (27 ) $ — $ — $ (2 ) $ — $ — $ (278 ) $ 2 $ — $ — Alt-A private-label securities 597 36 — — (267 ) — (45 ) (44 ) 28 305 15 Subprime private-label securities 1,307 36 — — (611 ) — (88 ) — — 644 10 Mortgage revenue bonds 722 (41 ) — — (220 ) — (12 ) — — 449 (33 ) Other 99 4 — — (100 ) — (3 ) — — — — Total trading securities $ 3,030 $ 8 (6)(7) $ — $ — $ (1,200 ) $ — $ (148 ) $ (322 ) $ 30 $ 1,398 $ (8 ) Available-for-sale securities: Mortgage-related: Fannie Mae $ — $ — $ — $ 421 $ (425 ) $ — $ (8 ) $ — $ 12 $ — $ — Freddie Mac 6 — — — — — (1 ) (2 ) 1 4 — Alt-A private-label securities 3,140 215 (173 ) — (1,504 ) — (436 ) (538 ) 337 1,041 — Subprime private-label securities 5,240 599 (382 ) — (1,575 ) — (601 ) — — 3,281 — Mortgage revenue bonds 4,023 51 (104 ) — (410 ) — (859 ) — — 2,701 — Other 2,671 (26 ) (2 ) — (1,012 ) — (227 ) — — 1,404 — Total available-for-sale securities $ 15,080 $ 839 (7)(8) $ (661 ) $ 421 $ (4,926 ) $ — $ (2,132 ) $ (540 ) $ 350 $ 8,431 $ — Mortgage loans $ 1,833 $ 57 (6)(7) $ — $ 5 $ — $ — $ (350 ) $ (377 ) $ 309 $ 1,477 $ (20 ) Net derivatives 45 (55 ) (6) — — — (4 ) 169 (7 ) 9 157 (2 ) Long-term debt: Of Fannie Mae: Senior floating $ (363 ) $ (6 ) $ — $ — $ — $ — $ — $ — $ — $ (369 ) $ (6 ) Of consolidated trusts (527 ) (9 ) — — — (66 ) 57 228 (179 ) (496 ) 17 Total long-term debt $ (890 ) $ (15 ) (6) $ — $ — $ — $ (66 ) $ 57 $ 228 $ (179 ) $ (865 ) $ 11 Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Year Ended December 31, 2014 Total Gains (Losses) (Realized/Unrealized) Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of December 31, 2014 (5)(6) Balance, December 31, 2013 Included in Net Income Included in Total Other Comprehensive Income (Loss) (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 (4) Transfers into Level 3 (4) Balance, December 31, 2014 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 42 $ (27 ) $ — $ 6 $ — $ — $ (2 ) $ (39 ) $ 325 $ 305 $ (18 ) Freddie Mac 2 — — — — — — (2 ) — — — Alt-A private-label securities 618 88 — — (58 ) — (81 ) (226 ) 256 597 97 Subprime private-label securities 1,448 270 — — (241 ) — (170 ) — — 1,307 234 Mortgage revenue bonds 565 168 — — — — (11 ) — — 722 160 Other 99 13 — — — — (13 ) — — 99 13 Total trading securities $ 2,774 $ 512 (6)(7) $ — $ 6 $ (299 ) $ — $ (277 ) $ (267 ) $ 581 $ 3,030 $ 486 Available-for-sale securities: Mortgage-related: Fannie Mae $ 7 $ — $ — $ — $ — $ — $ (1 ) $ (8 ) $ 2 $ — $ — Freddie Mac 8 — — — — — (1 ) (2 ) 1 6 — Alt-A private-label securities 3,791 172 (26 ) — (393 ) — (471 ) (1,738 ) 1,805 3,140 — Subprime private-label securities 7,068 447 301 — (1,730 ) — (846 ) — — 5,240 — Mortgage revenue bonds 5,253 (32 ) 554 — (70 ) — (1,682 ) — — 4,023 — Other 2,885 19 103 — — — (336 ) — — 2,671 — Total available-for-sale securities $ 19,012 $ 606 (7)(8) $ 932 $ — $ (2,193 ) $ — $ (3,337 ) $ (1,748 ) $ 1,808 $ 15,080 $ — Mortgage loans $ 2,704 $ 260 (6)(7) $ — $ 36 $ — $ — $ (344 ) $ (1,113 ) $ 290 $ 1,833 $ 53 Net derivatives (40 ) 103 (6) — — — — (21 ) (2 ) 5 45 77 Long-term debt: Of Fannie Mae: Senior floating $ (955 ) $ (142 ) $ — $ — $ — $ (750 ) $ 19 $ 1,465 $ — $ (363 ) $ (97 ) Of consolidated trusts (518 ) (53 ) — — — (1 ) 62 111 (128 ) (527 ) (49 ) Total long-term debt $ (1,473 ) $ (195 ) (6) $ — $ — $ — $ (751 ) $ 81 $ 1,576 $ (128 ) $ (890 ) $ (146 ) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Year Ended December 31, 2013 Total Gains (Losses) (Realized/Unrealized) Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of December 31, 2013 (5)(6) Balance, December 31, 2012 Included in Net Income Included in Total Other Comprehensive Income (Loss) (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 (4) Transfers into Level 3 (4) Balance, December 31, 2013 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 68 $ (9 ) $ — $ — $ — $ — $ (17 ) $ — $ — $ 42 $ (9 ) Freddie Mac 2 — — — — — — — — 2 — Ginnie Mae 1 — — — — — (1 ) (3 ) 3 — — Alt-A private-label securities 104 256 — — — — (115 ) (435 ) 808 618 223 Subprime private-label securities 1,319 328 — — (50 ) — (149 ) — — 1,448 322 Mortgage revenue bonds 675 (101 ) — — — — (9 ) — — 565 (101 ) Other 117 (5 ) — — — — (13 ) — — 99 (5 ) Total trading securities $ 2,286 $ 469 (6)(7) $ — $ — $ (50 ) $ — $ (304 ) $ (438 ) $ 811 $ 2,774 $ 430 Available-for-sale securities: Mortgage-related: Fannie Mae $ 29 $ — $ (1 ) $ — $ — $ — $ (7 ) $ (14 ) $ — $ 7 $ — Freddie Mac 10 — (1 ) — — — (2 ) (1 ) 2 8 — Ginnie Mae — — — — — — — (1 ) 1 — — Alt-A private-label securities 6,564 144 464 — (2,664 ) — (1,040 ) (3,357 ) 3,680 3,791 — Subprime private-label securities 7,447 120 1,527 359 (1,317 ) — (1,068 ) — — 7,068 — Mortgage revenue bonds 7,837 25 (449 ) — (35 ) — (2,125 ) — — 5,253 — Other 3,147 13 125 — — — (400 ) — — 2,885 — Total available-for-sale securities $ 25,034 $ 302 (7)(8) $ 1,665 $ 359 $ (4,016 ) $ — $ (4,642 ) $ (3,373 ) $ 3,683 $ 19,012 $ — Mortgage loans $ 2,634 $ 282 (6)(7) $ — $ 346 $ (393 ) $ — $ (459 ) $ (352 ) $ 646 $ 2,704 $ 50 Net derivatives 14 (165 ) (6) — — — — 97 16 (2 ) (40 ) (51 ) Long-term debt: Of Fannie Mae: Senior floating $ (400 ) $ 76 $ — $ — $ — $ (674 ) $ 43 $ — $ — $ (955 ) $ 76 Of consolidated trusts (1,128 ) (250 ) — — — (21 ) 537 434 (90 ) (518 ) (80 ) Total long-term debt $ (1,528 ) $ (174 ) (6) $ — $ — $ — $ (695 ) $ 580 $ 434 $ (90 ) $ (1,473 ) $ (4 ) __________ (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 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 gains (losses), net” in our consolidated statements of operations and comprehensive income. (7) Gains (losses) are included in “Net interest income” in our consolidated statements of operations and comprehensive income. (8) Gains (losses) are included in “Investment gains, net” in our 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 December 31, 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) $ 305 Consensus Default Rate (%) 1.3 - 4.9 3.6 Prepayment Speed (%) 2.2 - 4.5 3.7 Severity (%) 20.5 - 95.0 69.3 Spreads (bps) 219.0 - 263.3 253.1 Total Alt-A private-label securities 305 Subprime private-label securities (2) 526 Consensus Default Rate (%) 4.2 - 8.4 5.9 Prepayment Speed (%) 0.4 - 5.3 3.3 Severity (%) 55.9 - 95.0 73.7 Spreads (bps) 285.0 285.0 73 Consensus 45 Other Total subprime private-label securities 644 Mortgage revenue bonds 437 Discounted Cash Flow Spreads (bps) 1.5 - 376.2 298.9 12 Other Total mortgage revenue bonds 449 Total trading securities $ 1,398 Fair Value Measurements as of December 31, 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) 671 Consensus Default Rate (%) 0.5 - 40.7 3.4 Prepayment Speed (%) 1.7 - 72.6 13.5 Severity (%) 1.4 - 95.0 58.5 Spreads (bps) 225.6 - 280.4 260.0 201 Consensus 169 Discounted Cash Flow Default Rate (%) 4.0 - 5.0 4.8 Prepayment Speed (%) 4.0 - 7.5 6.4 Severity (%) 50.0 - 64.0 59.2 Spreads (bps) 260.0 - 369.4 296.5 Total Alt-A private-label securities 1,041 Subprime private-label securities (2) 343 Single Vendor Default Rate (%) 2.5 - 7.5 4.8 Prepayment Speed (%) 1.9 - 5.7 3.3 Severity (%) 67.6 - 85.7 72.7 Spreads (bps) 285.0 - 340.0 299.6 1,848 Consensus Default Rate (%) 0.5 - 11.3 5.9 Prepayment Speed (%) 0.5 - 11.2 3.8 Severity (%) 20.0 - 95.0 79.0 Spreads (bps) 255.0 - 285.0 283.3 945 Consensus 145 Other Total subprime private-label securities 3,281 Mortgage revenue bonds 991 Single Vendor Spreads (bps) (33.1 ) - 386.8 37.9 1,462 Discounted Cash Flow Spreads (bps) (15.8 ) - 379.1 283.8 248 Other Total mortgage revenue bonds 2,701 Other 683 Consensus Default Rate (%) 0.5 - 4.6 3.4 Prepayment Speed (%) 2.5 - 15.5 4.7 Severity (%) 6.6 - 95.0 65.7 Spreads (bps) 200.0 - 454.4 315.6 520 Discounted Cash Flow Default Rate (%) 0.0 - 1.8 0.0 Prepayment Speed (%) 0.0 - 0.5 0.0 Severity (%) 95.0 95.0 Spreads (bps) 260.0 - 350.0 323.6 201 Other Total other 1,404 Total available-for-sale securities $ 8,431 Fair Value Measurements as of December 31, 2015 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Mortgage loans: Single-family $ 127 Build-Up Default Rate (%) 0.0 - 99.2 34.8 Prepayment Speed (%) 3.0 - 100.0 10.4 Severity (%) 0.0 - 100.0 39.9 632 Build-Up 234 Consensus Default Rate (%) 0.5 - 5.0 3.7 Prepayment Speed (%) 2.5 - 26.0 6.4 Severity (%) 20.0 - 89.1 69.0 Spreads (bps) 255.0 - 277.6 264.6 274 Consensus 54 Other Total single-family 1,321 Multifamily 156 Build-Up Spreads (bps) 70.0 - 327.2 158.8 Total mortgage loans $ 1,477 Net derivatives $ 17 Internal Model 136 Dealer Mark 4 Other Total net derivatives $ 157 Long-term debt: Of Fannie Mae: Senior floating $ (369 ) Discounted Cash Flow Of consolidated trusts (4) (181 ) Consensus Default Rate (%) 0.5 - 3.8 3.4 Prepayment Speed (%) 2.5 - 26.0 5.6 Severity (%) 20.0 - 80.6 67.8 Spreads (bps) 255.0 - 270.0 265.8 (149 ) Consensus (166 ) Other Total of consolidated trusts (496 ) Total long-term debt $ (865 ) 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, Freddie Mac and Ginnie Mae 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 following table displays valuation techniques for our Level 3 assets measured at fair value on a nonrecurring basis. The significant unobservable inputs related to these techniques primarily relate to collateral dependent valuations. The related ranges and weighted averages are not meaningful when aggregated as they vary significantly from property to property. Fair Value Measurements as of December 31, Valuation Techniques 2015 2014 (Dollars in millions) Nonrecurring fair value measurements: Mortgage loans held for sale, at lower of cost or fair value Consensus $ 3,651 $ 110 Single Vendor 336 — Other 4 — Total mortgage loans held for sale, at lower of cost or fair value 3,991 110 Single-family mortgage loans held for investment, at amortized cost Internal Model 6,379 16,654 Other — 60 Total single-family mortgage loans held for investment, at amortized cost 6,379 16,714 Multifamily mortgage loans held for investment, at amortized cost Broker Price Opinions 82 45 Asset Manager Estimate 236 580 Other 5 — Total multifamily mortgage loans held for investment, at amortized cost 323 625 Acquired property, net: Single-family Accepted Offers 541 864 Appraisals 1,117 1,509 Walk Forwards 433 1,173 Internal Model 986 1,045 Other 134 191 Total single-family 3,211 4,782 Multifamily Broker Price Opinions — 127 Other — 13 Total multifamily — 140 Other assets Other 30 45 Total nonrecurring assets at fair value $ 13,934 $ 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 consolidated balance sheets. The fair values of these commitments are included as “Mortgage loans held for investment, net of allowance for loan losses.” The disclosure excludes all non-financial instruments; therefore, the fair value of our financial assets and liabilities does not represent the underlying fair value of our total consolidated assets and liabilities. As of December 31, 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 $ 45,553 $ 34,953 $ 10,600 $ — $ — $ 45,553 Federal funds sold and securities purchased under agreements to resell or similar arrangements 27,350 — 27,350 — — 27,350 Trading securities 39,908 29,485 9,025 1,398 — 39,908 Available-for-sale securities 20,230 — 11,799 8,431 — 20,230 Mortgage loans held for sale 5,361 — 157 5,541 — 5,698 Mortgage loans held for investment, net of allowance for loan losses: Of Fannie Mae 206,544 — 26,544 193,670 — 220,214 Of consolidated trusts 2,807,739 — 2,675,982 157,685 — 2,833,667 Mortgage loans held for investment 3,014,283 — 2,702,526 351,355 — 3,053,881 Advances to lenders 4,308 — 3,902 394 — 4,296 Derivative assets at fair value 894 — 4,729 189 (4,024 ) 894 Guaranty assets and buy-ups 184 — — 544 — 544 Total financial assets $ 3,158,071 $ 64,438 $ 2,770,088 $ 367,852 $ (4,024 ) $ 3,198,354 Financial liabilities: Federal funds purchased and securities sold under agreements to repurchase $ 62 $ — $ 62 $ — $ — $ 62 Short-term debt: Of Fannie Mae 71,007 — 71,006 — — 71,006 Of consolidated trusts 943 — — 944 — 944 Long-term debt: Of Fannie Mae 315,128 — 324,248 898 — 325,146 Of consolidated trusts 2,810,593 — 2,819,733 27,175 — 2,846,908 Derivative liabilities at fair value 424 — 9,042 32 (8,650 ) 424 Guaranty obligations 329 — — 1,012 — 1,012 Total financial liabilities $ 3,198,486 $ — $ 3,224,091 $ 30,061 $ (8,650 ) $ 3,245,502 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 December 31, 2015 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 $ 14,075 $ 11,133 $ 23,609 $ 15,629 $ 6,403 $ 19,483 Unpaid principal balance 13,661 11,263 21,604 15,001 6,512 17,810 __________ (1) Includes nonaccrual loans with a fair value of $238 million and $240 million as of December 31, 2015 and 2014 , respectively. The difference between unpaid principal balance and the fair value of these nonaccrual loans as of December 31, 2015 and 2014 is $59 million and $75 million , respectively. Includes loans that are 90 days or more past due with a fair value of $256 million and $271 million as of December 31, 2015 and 2014 , respectively. The difference between unpaid principal balance and the fair value of these 90 or more days past due loans as of December 31, 2015 and 2014 is $52 million and $78 million , respectively. The following table displays 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 gains (losses), net” in our consolidated statements of operations and comprehensive income. For the Year Ended December 31, 2015 2014 2013 Loans Long-Term Debt Total Gains (Losses) Loans Long-Term Debt Total Gains (Losses) Loans Long-Term Debt Total Gains (Losses) (Dollars in millions) Changes in instrument-specific credit risk $ 86 $ 39 $ 125 $ 60 $ 216 $ 276 $ (142 ) $ (31 ) $ (173 ) Other changes in fair value (191 ) 146 (45 ) 670 (505 ) 165 (730 ) 346 (384 ) Fair value gains (losses), net $ (105 ) $ 185 $ 80 $ 730 $ (289 ) $ 441 $ (872 ) $ 315 $ (557 )

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Non Cancelable Future Commitments by Remaining Maturity [Table Text Block]	The following table summarizes by remaining maturity, non-cancelable future commitments related to loan and mortgage purchases, operating leases and other agreements. As of December 31, 2015 Loans and Mortgage-Related Securities (1) Operating Leases (2) Other (3) (Dollars in millions) 2016 $ 58,715 $ 44 $ 59 2017 — 46 15 2018 — 32 11 2019 — 49 5 2020 — 53 4 Thereafter — 718 — Total $ 58,715 $ 942 $ 94 __________ (1) Primarily includes $58.5 billion that has been accounted for as mortgage commitment derivatives. (2) Includes amounts related to office buildings and equipment leases. (3) Includes purchase commitments for certain telecommunications services, computer software and services, and other agreements and commitments.

Selected Quarterly Financial 56

Selected Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Schedule of Selected Quarterly Financial Information [Table Text Block]	The consolidated statements of operations for the quarterly periods in 2015 and 2014 are unaudited and in the opinion of management include all adjustments, consisting of normal recurring adjustments, necessary for a fair presentation of our consolidated statements of operations. Certain prior period amounts have been reclassified to conform to the current period presentation. The operating results for the interim periods are not necessarily indicative of the operating results to be expected for a full year or for other interim periods. For the 2015 Quarter Ended March 31 June 30 September 30 December 31 (Dollars and shares in millions, except per share amounts) Interest income: Trading securities $ 115 $ 116 $ 99 $ 114 Available-for-sale securities 376 294 261 225 Mortgage loans 27,044 26,682 26,980 26,993 Other 33 34 37 39 Total interest income 27,568 27,126 27,377 27,371 Interest expense: Short-term debt 29 33 37 47 Long-term debt 22,472 21,416 21,752 22,247 Total interest expense 22,501 21,449 21,789 22,294 Net interest income 5,067 5,677 5,588 5,077 Benefit (provision) for credit losses 533 (1,033 ) 1,550 (255 ) Net interest income after benefit (provision) for credit losses 5,600 4,644 7,138 4,822 Investment gains, net 342 514 299 181 Fair value gains (losses), net (1,919 ) 2,606 (2,589 ) 135 Fee and other income 308 556 259 225 Non-interest income (loss) (1,269 ) 3,676 (2,031 ) 541 Administrative expenses: Salaries and employee benefits 351 331 317 320 Professional services 271 251 219 243 Occupancy expenses 43 43 43 53 Other administrative expenses 58 64 373 70 Total administrative expenses 723 689 952 686 Foreclosed property expense 473 182 497 477 TCCA fees 382 397 413 429 Other expenses (income), net (5 ) 202 215 201 Total expenses 1,573 1,470 2,077 1,793 Income before federal income taxes 2,758 6,850 3,030 3,570 Provision for federal income taxes (870 ) (2,210 ) (1,070 ) (1,103 ) Net income 1,888 4,640 1,960 2,467 Less: Net income attributable to noncontrolling interest — — — (1 ) Net income attributable to Fannie Mae 1,888 4,640 1,960 2,466 Dividends distributed or available for distribution to senior preferred stockholder (1,796 ) (4,359 ) (2,202 ) (2,859 ) Net income (loss) attributable to common stockholders (Note 11) $ 92 $ 281 $ (242 ) $ (393 ) Earnings (loss) per share: Basic and Diluted $ 0.02 $ 0.05 $ (0.04 ) $ (0.07 ) Weighted-average common shares outstanding: Basic 5,762 5,762 5,762 5,762 Diluted 5,893 5,893 5,762 5,762 For the 2014 Quarter Ended March 31 June 30 September 30 December 31 (Dollars and shares in millions, except per share amounts) Interest income: Trading securities $ 127 $ 143 $ 151 $ 132 Available-for-sale securities 440 414 395 373 Mortgage loans 28,588 28,165 27,779 27,588 Other 24 24 29 33 Total interest income 29,179 28,746 28,354 28,126 Interest expense: Short-term debt 20 21 26 27 Long-term debt 24,421 23,821 23,144 22,957 Total interest expense 24,441 23,842 23,170 22,984 Net interest income 4,738 4,904 5,184 5,142 Benefit for credit losses 774 1,639 1,085 466 Net interest income after benefit for credit losses 5,512 6,543 6,269 5,608 Investment gains, net 95 483 171 187 Fair value losses, net (1,190 ) (934 ) (207 ) (2,502 ) Fee and other income 4,355 383 826 323 Non-interest income (loss) 3,260 (68 ) 790 (1,992 ) Administrative expenses: Salaries and employee benefits 325 319 337 340 Professional services 242 275 263 296 Occupancy expenses 50 47 47 59 Other administrative expenses 55 56 59 7 Total administrative expenses 672 697 706 702 Foreclosed property expense (income) (262 ) (214 ) 249 369 TCCA fees 322 335 351 367 Other expenses, net 131 238 61 48 Total expenses 863 1,056 1,367 1,486 Income before federal income taxes 7,909 5,419 5,692 2,130 Provision for federal income taxes (2,584 ) (1,752 ) (1,787 ) (818 ) Net income 5,325 3,667 3,905 1,312 Less: Net income attributable to noncontrolling interest — (1 ) — — Net income attributable to Fannie Mae 5,325 3,666 3,905 1,312 Dividends distributed or available for distribution to senior preferred stockholder (5,692 ) (3,712 ) (3,999 ) (1,920 ) Net loss attributable to common stockholders (Note 11) $ (367 ) $ (46 ) $ (94 ) $ (608 ) Loss per share: Basic and Diluted $ (0.06 ) $ (0.01 ) $ (0.02 ) $ (0.11 ) Weighted-average common shares outstanding: Basic and Diluted 5,762 5,762 5,762 5,762

Summary of Significant Accoun57

Summary of Significant Accounting Policies Organization (Details)	12 Months Ended
	Dec. 31, 2015segments
Accounting Policies [Abstract]
Number of Reportable Segments	3

Summary of Significant Accoun58

Summary of Significant Accounting Policies Related Parties (Details) - USD ($)	Dec. 31, 2015	Sep. 08, 2008	Feb. 29, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2016	Dec. 31, 2012	Sep. 07, 2008
Related Parties [Line Items]
Number of days after which we have not been paying debts or liabilities exceed assets FHFA must place us into receivership													60 days
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
Annual reduction of capital reserve from 2013 to 2018 based on the Senior Preferred Stock Purchase Agreement, Amendment	600,000,000				600,000,000								600,000,000
Capital reserve amount on January 2018	0				0								0
Payment Of Cash Dividends On Senior Preferred Stock To Treasury	2,200,000,000												10,278,000,000	$ 20,594,000,000	$ 82,452,000,000
Net worth (deficit)	$ 4,059,000,000				$ 4,059,000,000	$ 4,000,000,000			$ 3,720,000,000				$ 4,059,000,000	3,720,000,000	9,591,000,000		$ 7,224,000,000
Percentage of common shares attributable to warrants issued to Treasury as a percentage to total diluted common shares upon exercise of the right	79.90%				79.90%								79.90%
Income taxes paid													$ 1,170,000,000	2,815,000,000	2,350,000,000
Temporary Payroll Cut Continuation Act of 2011 (TCCA) fees					$ 429,000,000	413,000,000	$ 397,000,000	$ 382,000,000	367,000,000	$ 351,000,000	$ 335,000,000	$ 322,000,000	$ 1,621,000,000	1,375,000,000	1,001,000,000
Basis Points of Each Dollar of Unpaid Principal Balance	420.00%				420.00%								420.00%
Other expenses													$ 613,000,000	478,000,000	95,000,000
Trading, at fair value	$ 39,908,000,000				$ 39,908,000,000				31,504,000,000				39,908,000,000	31,504,000,000
Accrued interest receivable	7,726,000,000				7,726,000,000				8,193,000,000				7,726,000,000	8,193,000,000
Trading securities					114,000,000	$ 99,000,000	$ 116,000,000	$ 115,000,000	132,000,000	$ 151,000,000	$ 143,000,000	$ 127,000,000	444,000,000	553,000,000	779,000,000
U.S. Treasury Securities [Member]
Related Parties [Line Items]
Trading, at fair value	29,485,000,000				29,485,000,000				19,466,000,000				29,485,000,000	19,466,000,000
Scenario, Forecast [Member]
Related Parties [Line Items]
Undeclared Dividends On Senior Preferred Stock Next Quarter				$ 2,900,000,000
Series 2008-2 Senior Preferred Stock [Member]
Related Parties [Line Items]
Shares of variable liquidation preference senior preferred stock issued		1,000,000
Aggregate liquidation preference of senior preferred stock		$ 1,000,000,000
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				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 remaining funding available 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 for the fiscal year based on the amended Senior Preferred Stock Purchase agreement	1,800,000,000				1,800,000,000				2,400,000,000				1,800,000,000	2,400,000,000
Annual reduction of capital reserve from 2013 to 2018 based on the Senior Preferred Stock Purchase Agreement, Amendment	$ 600,000,000				$ 600,000,000								$ 600,000,000
Percentage of common shares attributable to warrants issued to Treasury as a percentage to total diluted common shares upon exercise of the right	79.90%				79.90%								79.90%					79.90%
Common stock warrant exercise price per share																		$ 0.00001
Fair value of the warrant at issuance		$ 3,500,000,000
Home Affordable Modification Program administrative expense reimbursements													$ 68,000,000	71,000,000	92,000,000
Income taxes paid													1,200,000,000	2,800,000,000	2,400,000,000
Income tax refund													$ 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%
Increase of Guarantee Fee Rate Resulting from the Temporary Payroll Tax Cut Continuation Act of 2011.	1000.00%				1000.00%								1000.00%
Temporary Payroll Cut Continuation Act of 2011 (TCCA) fees					$ 429,000,000								$ 1,621,000,000	1,375,000,000	1,001,000,000
TCCA guaranty fee remitted													1,600,000,000	1,300,000,000	829,000,000
US Treasury [Member] | U.S. Treasury Securities [Member]
Related Parties [Line Items]
Trading, at fair value	$ 29,500,000,000				29,500,000,000				19,500,000,000				29,500,000,000	19,500,000,000
Accrued interest receivable	15,000,000				15,000,000				16,000,000				15,000,000	16,000,000
Trading securities													35,000,000	18,000,000	28,000,000
US Treasury [Member] | Temporary Credit and Liquidity Facilities Program [Member]
Related Parties [Line Items]
Principal and interest outstanding	0				0				390,000,000				0	390,000,000
US Treasury [Member] | New Issue Bond [Member]
Related Parties [Line Items]
Principal and interest outstanding	3,700,000,000				3,700,000,000				4,200,000,000				3,700,000,000	4,200,000,000
Loss of principal or interest under Treasury's Temporary Credit and Liquid Facilities and New Issue Bond Programs	0				0								0
US Treasury [Member] | Scenario, Forecast [Member]
Related Parties [Line Items]
Capital reserve amount for the fiscal year based on the amended Senior Preferred Stock Purchase agreement																$ 1,200,000,000
US Treasury [Member] | Scenario, Forecast [Member] | Capital Magnet Fund [Member]
Related Parties [Line Items]
Other expenses			$ 57,000,000
US Treasury [Member] | Scenario, Forecast [Member] | HOPE Reserve Fund [Member]
Related Parties [Line Items]
Other expenses			$ 54,000,000
Freddie Mac [Member] | Freddie Mac [Member]
Related Parties [Line Items]
Fair value of mortgage-related securities	5,600,000,000				5,600,000,000				6,900,000,000				5,600,000,000	6,900,000,000
Accrued interest receivable	$ 22,000,000				$ 22,000,000				$ 26,000,000				22,000,000	26,000,000
Investment income, interest													226,000,000	283,000,000	387,000,000
Federal Housing Finance Agency [Member]
Related Parties [Line Items]
FHFA assessment fees/expense													112,000,000	108,000,000	$ 109,000,000
Common Securitization Solutions [Member]
Related Parties [Line Items]
Payments to Acquire Equity Method Investments													$ 66,000,000	$ 43,000,000

Summary of Significant Accoun59

Summary of Significant Accounting Policies Use of Estimates (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Jan. 01, 2015
Change in Accounting Estimate [Line Items]
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount		$ (58,300)
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
Single-Family Individually Impaired Loan Loss Models Update [Member]
Change in Accounting Estimate [Line Items]
Allowance for Loan and Lease Losses, Period Increase (Decrease)	$ 600	$ 2,200

Summary of Significant Accoun60

Summary of Significant Accounting Policies Investments in Securities (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Accounting Policies [Abstract]
Fair value of guaranty obligation	$ 488	$ 797

Summary of Significant Accoun61

Summary of Significant Accounting Policies Reserve for Guaranty Losses (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Accounting Policies [Abstract]
Reserve for Guaranty Losses	$ 639	$ 1,200

Summary of Significant Accoun62

Summary of Significant Accounting Policies Advances to Lenders (Details)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Maximum term of early lender funding advances	60 days

Summary of Significant Accoun63

Summary of Significant Accounting Policies Fee and Other Income (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Gain Contingencies [Line Items]
Fee and other income	$ 225	$ 259	$ 556	$ 308	$ 323	$ 826	$ 383	$ 4,355	$ 1,348	$ 5,887	$ 3,930
Private Label Securities Settlements [Member]
Gain Contingencies [Line Items]
Fee and other income									$ 21	$ 4,800	$ 2,200

Summary of Significant Accoun64

Summary of Significant Accounting Policies Employee Retirement Benefits (Details) - Pension Plan [Member] $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
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

Consolidations and Transfers 65

Consolidations and Transfers of Financial Assets Types of VIEs (Details)	12 Months Ended
	Dec. 31, 2015USD ($)
Consolidations and Transfers of Financial Assets [Abstract]
Investment Tax Credit	$ 0

Consolidations and Transfers 66

Consolidations and Transfers of Financial Assets Unconsolidated VIEs (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Variable Interest Entities [Line Items]
Trading, at fair value	$ 39,908	$ 31,504
Available-for-sale securities	20,230	30,654
Other assets	17,553	19,992
Other liabilities	(10,393)	(12,069)
Unconsolidated VIEs [Member] | Mortgage-related securities [Member]
Variable Interest Entities [Line Items]
Trading, at fair value	10,300	11,863
Available-for-sale securities	18,580	27,819
Other assets	100	111
Other liabilities	(827)	(1,440)
Net carrying amount	28,153	38,353
Fannie Mae Securities [Member]
Variable Interest Entities [Line Items]
Unconsolidated Fannie Mae MBS, Trading	4,704	4,790
Unconsolidate Fannie MBS, AFS	3,936	5,043
Non-Fannie Mae Securities [Member]
Variable Interest Entities [Line Items]
Trading, at fair value	5,596	7,073
Available-for-sale securities	$ 14,644	$ 22,776

Consolidations and Transfers 67

Consolidations and Transfers of Financial Assets Unconsolidated VIE narrative (Details) - Unconsolidated VIEs [Member] - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Collateralized mortgage backed securities [Member]
Variable Interest Entities [Line Items]
Maximum exposure to loss related to unconsolidated MBS	$ 34,434	$ 45,311
Total assets of unconsolidated mortgage-backed trusts	220,000	250,000
Partnership Interest [Member]
Variable Interest Entities [Line Items]
Total assets of unconsolidated mortgage-backed trusts	$ 4,900	$ 5,800

Consolidations and Transfers 68

Consolidations and Transfers of Financial Assets Transfers of Financial Assets (Details) - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Transfers of Financial Assets [Line Items]
Unpaid principal balance portfolio securitizations	$ 212	$ 160.4	$ 228.5
Unconsolidated VIEs [Member]
Transfers of Financial Assets [Line Items]
Principal and interest received on retained interest	1.2	1.5	$ 1.7
Unconsolidated VIEs [Member] | Single Class MBS, REMIC & Megas [Member]
Transfers of Financial Assets [Line Items]
Unpaid principal balance of retained interests	5.5	6.3
Retained interest, at fair value	$ 6.8	$ 7.6

Consolidations and Transfers 69

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

Loans in Mortgage Portfolio (De

Loans in Mortgage Portfolio (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	$ 3,010,753	$ 3,019,300
Cost basis and fair value adjustments, net	36,842	35,735
Allowance for loan losses for loans held for investment	(27,951)	(35,541)	$ (43,846)	$ (58,795)
Total mortgage loans	3,019,644	3,019,494
Carrying value of loans redesignated from HFI to HFS	8,600	2,200	1,300
Carrying value of loans redesignated from HFS to HFI		285
Sale of loans, unpaid principal balance	3,600	1,900	1,200
Single-Family [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	2,812,411	2,832,000
Recorded investment of single-family mortgage loans referred to foreclosure	25,600
Multifamily [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	198,342	187,300
Fannie Mae [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	251,336	285,371
Cost basis and fair value adjustments, net	(12,939)	(12,705)
Allowance for loan losses for loans held for investment	(26,510)	(33,117)	(40,521)	(50,519)
Total mortgage loans	211,887	239,549
Fannie Mae [Member] | Single-Family [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	238,237	262,116
Fannie Mae [Member] | Multifamily [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	13,099	23,255
Consolidated Trusts [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	2,759,417	2,733,929
Cost basis and fair value adjustments, net	49,781	48,440
Allowance for loan losses for loans held for investment	(1,441)	(2,424)	$ (3,325)	$ (8,276)
Total mortgage loans	2,807,757	2,779,945
Consolidated Trusts [Member] | Single-Family [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	2,574,174	2,569,884
Consolidated Trusts [Member] | Multifamily [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	$ 185,243	$ 164,045

Mortgage Loans Aging (Details)

Mortgage Loans Aging (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	$ 34,814	$ 34,867
60 - 89 days delinquent	9,717	10,352
Seriously delinquent	35,061	54,008
Total delinquent	79,592	99,227
Current	2,956,120	2,948,567
Total recorded investment in loans	3,035,712	3,047,794
Recorded investment in loans 90 days or more delinquent and accruing interest	349	374
Recorded investment in nonaccrual loans	44,846	64,645
Single-Family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	34,791	34,807
60 - 89 days delinquent	9,717	10,352
Seriously delinquent	34,938	53,919
Total delinquent	79,446	99,078
Current	2,756,092	2,759,483
Total recorded investment in loans	2,835,538	2,858,561
Recorded investment in loans 90 days or more delinquent and accruing interest	349	374
Recorded investment in nonaccrual loans	$ 44,255	$ 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	$ 29,154	$ 29,130
60 - 89 days delinquent	7,937	8,396
Seriously delinquent	26,346	38,248
Total delinquent	63,437	75,774
Current	2,598,756	2,580,446
Total recorded investment in loans	2,662,193	2,656,220
Recorded investment in loans 90 days or more delinquent and accruing interest	46	55
Recorded investment in nonaccrual loans	34,216	46,556
Single-Family [Member] | Government [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	58	63
60 - 89 days delinquent	24	26
Seriously delinquent	291	305
Total delinquent	373	394
Current	40,461	44,927
Total recorded investment in loans	40,834	45,321
Recorded investment in loans 90 days or more delinquent and accruing interest	291	305
Recorded investment in nonaccrual loans	0	0
Single-Family [Member] | Alt-A [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	4,085	4,094
60 - 89 days delinquent	1,272	1,414
Seriously delinquent	6,141	11,603
Total delinquent	11,498	17,111
Current	84,603	95,650
Total recorded investment in loans	96,101	112,761
Recorded investment in loans 90 days or more delinquent and accruing interest	6	8
Recorded investment in nonaccrual loans	7,407	13,007
Single-Family [Member] | Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	1,494	1,520
60 - 89 days delinquent	484	516
Seriously delinquent	2,160	3,763
Total delinquent	4,138	5,799
Current	32,272	38,460
Total recorded investment in loans	36,410	44,259
Recorded investment in loans 90 days or more delinquent and accruing interest	6	6
Recorded investment in nonaccrual loans	2,632	4,259
Multifamily [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	23	60
Seriously delinquent	123	89
Total delinquent	146	149
Current	200,028	189,084
Total recorded investment in loans	200,174	189,233
Recorded investment in loans 90 days or more delinquent and accruing interest	0	0
Recorded investment in nonaccrual loans	$ 591	$ 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	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment	$ 3,035,712	$ 3,047,794
Single-Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment	2,835,538	2,858,561
Single-Family [Member] | Primary [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment	2,662,193	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	2,228,533	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	250,373	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	122,939	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	27,875	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	14,625	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	4,520	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	13,328	23,586
Single-Family [Member] | Alt-A [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment	96,101	112,761
Single-Family [Member] | Alt-A [Member] | Estimated Mark-to-Market Loan-to-Value Ratio Less Than or Equal to 80% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment	59,000	60,851
Single-Family [Member] | Alt-A [Member] | Estimated Mark-to-Market Loan-to-Value Ratio Greater Than 80% and Less Than or Equal to 90% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment	12,588	15,151
Single-Family [Member] | Alt-A [Member] | Estimated Mark-to-Market Loan-to-Value Ratio Greater Than 90% and Less Than or Equal to 100% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment	9,345	12,490
Single-Family [Member] | Alt-A [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	6,231	8,998
Single-Family [Member] | Alt-A [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	3,730	6,033
Single-Family [Member] | Alt-A [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	1,260	2,114
Single-Family [Member] | Alt-A [Member] | Estimated Mark-to-Market Loan-to-Value Ratio Greater Than 125% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment	3,947	7,124
Single-Family [Member] | Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment	36,410	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	21,274	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	4,936	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	3,861	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	2,596	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	1,592	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	545	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	1,606	3,000
Single-Family [Member] | Government [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment	$ 40,834	$ 45,321

Mortgage Loans Credit Quality73

Mortgage Loans Credit Quality Indicators - MF (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment	$ 3,035,712	$ 3,047,794
Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment	200,174	189,233
Multifamily [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment	194,132	182,079
Multifamily [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment	3,202	3,070
Multifamily [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment	2,833	3,842
Multifamily [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment	$ 7	$ 242

Mortgage Loans Individually Imp

Mortgage Loans Individually Impaired Loans (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	$ 162,230	$ 177,630
Individually impaired loans with related allowance recorded: total recorded investment	152,765	168,510
Related Allowance for loan losses	25,517	31,375
Individually impaired loans with no related allowance recorded: unpaid principal balance	21,245	22,563
Individually impaired loans with no related allowance recorded: total recorded investment	19,404	19,676
Total individually impaired loans: unpaid principal balance	183,475	200,193
Total individually impaired loans: total recorded investment	172,169	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	161,580	176,400
Individually impaired loans with related allowance recorded: total recorded investment	152,111	167,269
Related Allowance for loan losses	25,437	31,200
Individually impaired loans with no related allowance recorded: unpaid principal balance	20,892	21,998
Individually impaired loans with no related allowance recorded: total recorded investment	19,050	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	116,477	125,960
Individually impaired loans with related allowance recorded: total recorded investment	110,502	120,221
Related Allowance for loan losses	16,745	20,327
Individually impaired loans with no related allowance recorded: unpaid principal balance	15,891	16,704
Individually impaired loans with no related allowance recorded: total recorded investment	14,725	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	322	281
Individually impaired loans with related allowance recorded: total recorded investment	327	285
Related Allowance for loan losses	59	46
Individually impaired loans with no related allowance recorded: unpaid principal balance	58	61
Individually impaired loans with no related allowance recorded: total recorded investment	54	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 [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	31,888	35,492
Individually impaired loans with related allowance recorded: total recorded investment	29,103	32,816
Related Allowance for loan losses	6,217	7,778
Individually impaired loans with no related allowance recorded: unpaid principal balance	3,721	3,993
Individually impaired loans with no related allowance recorded: total recorded investment	3,169	3,119
Single-Family [Member] | Alt-A [Member] | 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	12,893	14,667
Individually impaired loans with related allowance recorded: total recorded investment	12,179	13,947
Related Allowance for loan losses	2,416	3,049
Individually impaired loans with no related allowance recorded: unpaid principal balance	1,222	1,240
Individually impaired loans with no related allowance recorded: total recorded investment	1,102	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	650	1,230
Individually impaired loans with related allowance recorded: total recorded investment	654	1,241
Related Allowance for loan losses	80	175
Individually impaired loans with no related allowance recorded: unpaid principal balance	353	565
Individually impaired loans with no related allowance recorded: total recorded investment	$ 354	568
Multifamily [Member] | Interest Receivable [Member]
Financing Receivable, Impaired [Line Items]
Related Allowance for loan losses		$ 6

Mortgage Loans Individually I75

Mortgage Loans Individually Impaired Loans - 2 (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	$ 159,325	$ 172,061	$ 178,036
Individually impaired loans with related allowance recorded: total interest income recognized	5,628	5,882	6,011
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	393	631	791
Individually impaired loans with no related allowance recorded: average recorded investment	21,199	19,164	16,376
Individually impaired loans with no related allowance recorded: total interest income recognized	1,346	1,178	1,920
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	105	274	292
Individually impaired loans: average recorded investment	180,524	191,225	194,412
Individually impaired loans: total interest income recognized	6,974	7,060	7,931
Individually impaired loans: interest income recognized on a cash basis	498	905	1,083
Table Footnote [Abstract]
Individually impaired loans: total interest income recognized	6,974	7,060	7,931
Single Family [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	158,352	170,362	175,484
Individually impaired loans with related allowance recorded: total interest income recognized	5,612	5,802	5,883
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	393	630	790
Individually impaired loans with no related allowance recorded: average recorded investment	20,757	17,692	14,513
Individually impaired loans with no related allowance recorded: total interest income recognized	1,336	1,114	1,823
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	105	274	289
Individually impaired loans: total interest income recognized	6,900	6,900	7,700
Table Footnote [Abstract]
Troubled debt restructuring recorded investment	170,300	185,200	187,600
Individually impaired loans: total interest income recognized	6,900	6,900	7,700
Individually impaired loans: contractual interest income	5,700	5,800	5,700
Individually impaired loans: effective yield adjustments	1,200	1,100	2,000
Single Family [Member] | Primary [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	114,737	121,926	124,659
Individually impaired loans with related allowance recorded: total interest income recognized	4,190	4,321	4,351
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	318	494	603
Individually impaired loans with no related allowance recorded: average recorded investment	15,796	13,852	11,442
Individually impaired loans with no related allowance recorded: total interest income recognized	1,039	864	1,369
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	91	215	227
Single Family [Member] | Government [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	299	270	213
Individually impaired loans with related allowance recorded: total interest income recognized	12	13	11
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	0	0	0
Individually impaired loans with no related allowance recorded: average recorded investment	55	67	112
Individually impaired loans with no related allowance recorded: total interest income recognized	4	5	8
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	0	0	0
Single Family [Member] | Alt-A [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	30,453	33,676	35,075
Individually impaired loans with related allowance recorded: total interest income recognized	1,034	1,066	1,096
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	54	100	135
Individually impaired loans with no related allowance recorded: average recorded investment	3,647	2,799	2,207
Individually impaired loans with no related allowance recorded: total interest income recognized	218	189	329
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	11	47	45
Single Family [Member] | Other [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	12,863	14,490	15,537
Individually impaired loans with related allowance recorded: total interest income recognized	376	402	425
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	21	36	52
Individually impaired loans with no related allowance recorded: average recorded investment	1,259	974	752
Individually impaired loans with no related allowance recorded: total interest income recognized	75	56	117
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	3	12	17
Multifamily [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	973	1,699	2,552
Individually impaired loans with related allowance recorded: total interest income recognized	16	80	128
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	0	1	1
Individually impaired loans with no related allowance recorded: average recorded investment	442	1,472	1,863
Individually impaired loans with no related allowance recorded: total interest income recognized	10	64	97
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	0	0	3
Table Footnote [Abstract]
Troubled debt restructuring recorded investment	$ 451	$ 716	$ 911

Mortgage Loans TDR (Details)

Mortgage Loans TDR (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)contracts	Dec. 31, 2014USD ($)contracts	Dec. 31, 2013USD ($)contracts
Financing Receivable, Modifications [Line Items]
Average term extension of a single-family modified loan	161 months	161 months	154 months
Average interest rate reduction of a single-family modified loan	0.74%	0.99%	1.68%
Number of loans troubled debt restructurings activity | contracts	82,418	119,412	155,040
Recorded investment troubled debt restructurings activity | $	$ 11,487	$ 18,328	$ 24,436
Number of loans troubled debt restructurings subsequent default | contracts	31,684	41,116	58,372
Recorded investment troubled debt restructurings subsequent default | $	$ 4,783	$ 6,499	$ 9,476
Single-Family [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity | contracts	82,406	119,393	155,007
Recorded investment troubled debt restructurings activity | $	$ 11,447	$ 17,475	$ 24,223
Number of loans troubled debt restructurings subsequent default | contracts	31,681	41,107	58,363
Recorded investment troubled debt restructurings subsequent default | $	$ 4,777	$ 6,457	$ 9,412
Single-Family [Member] | Primary [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity | contracts	71,293	100,956	126,998
Recorded investment troubled debt restructurings activity | $	$ 9,713	$ 14,301	$ 19,016
Number of loans troubled debt restructurings subsequent default | contracts	26,206	33,853	45,539
Recorded investment troubled debt restructurings subsequent default | $	$ 3,808	$ 5,095	$ 6,978
Single-Family [Member] | Government [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity | contracts	241	365	312
Recorded investment troubled debt restructurings activity | $	$ 27	$ 47	$ 35
Number of loans troubled debt restructurings subsequent default | contracts	118	124	130
Recorded investment troubled debt restructurings subsequent default | $	$ 16	$ 15	$ 17
Single-Family [Member] | Alt-A [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity | contracts	9,037	14,715	21,471
Recorded investment troubled debt restructurings activity | $	$ 1,374	$ 2,441	$ 3,794
Number of loans troubled debt restructurings subsequent default | contracts	4,128	5,392	9,601
Recorded investment troubled debt restructurings subsequent default | $	$ 706	$ 960	$ 1,732
Single-Family [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity | contracts	1,835	3,357	6,226
Recorded investment troubled debt restructurings activity | $	$ 333	$ 686	$ 1,378
Number of loans troubled debt restructurings subsequent default | contracts	1,229	1,738	3,093
Recorded investment troubled debt restructurings subsequent default | $	$ 247	$ 387	$ 685
Multifamily [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity | contracts	12	19	33
Recorded investment troubled debt restructurings activity | $	$ 40	$ 853	$ 213
Number of loans troubled debt restructurings subsequent default | contracts	3	9	9
Recorded investment troubled debt restructurings subsequent default | $	$ 6	$ 42	$ 64

Allowance for Loan Losses Rollf

Allowance for Loan Losses Rollforward by Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Jan. 01, 2015
Allowance for Loan Losses [Roll Forward]
Beginning balance	$ 35,541	$ 43,846	$ 58,795
Provision (benefit) for loan losses	(158)	(3,885)	(9,316)
Charge-offs	(9,774)	(6,469)	(8,867)
Recoveries	1,140	1,440	2,626
Transfers	0	0	0
Other	1,202	609	608
Ending balance	27,951	35,541	43,846
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	33,117	40,521	50,519
Provision (benefit) for loan losses	(321)	(4,425)	(6,984)
Charge-offs	(9,687)	(6,244)	(8,611)
Recoveries	1,124	1,190	2,115
Transfers	1,127	1,517	2,962
Other	1,150	558	520
Ending balance	26,510	33,117	40,521
Consolidated Trusts [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	2,424	3,325	8,276
Provision (benefit) for loan losses	163	540	(2,332)
Charge-offs	(87)	(225)	(256)
Recoveries	16	250	511
Transfers	(1,127)	(1,517)	(2,962)
Other	52	51	88
Ending balance	1,441	2,424	3,325
Single-Family [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	35,177	43,307	57,687
Provision (benefit) for loan losses	(68)	(3,781)	(8,896)
Charge-offs	(9,731)	(6,393)	(8,714)
Recoveries	1,136	1,440	2,626
Transfers	0	0	0
Other	1,195	604	604
Ending balance	27,709	35,177	43,307
Single-Family [Member] | Fannie Mae [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	32,956	40,202	49,848
Provision (benefit) for loan losses	(258)	(4,334)	(6,751)
Charge-offs	(9,647)	(6,168)	(8,458)
Recoveries	1,120	1,190	2,115
Transfers	1,123	1,513	2,932
Other	1,145	553	516
Ending balance	26,439	32,956	40,202
Single-Family [Member] | Consolidated Trusts [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	2,221	3,105	7,839
Provision (benefit) for loan losses	190	553	(2,145)
Charge-offs	(84)	(225)	(256)
Recoveries	16	250	511
Transfers	(1,123)	(1,513)	(2,932)
Other	50	51	88
Ending balance	1,270	2,221	3,105
Multifamily [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	364	539	1,108
Provision (benefit) for loan losses	(90)	(104)	(420)
Charge-offs	(43)	(76)	(153)
Recoveries	4	0	0
Transfers	0	0	0
Other	7	5	4
Ending balance	242	364	539
Multifamily [Member] | Fannie Mae [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	161	319	671
Provision (benefit) for loan losses	(63)	(91)	(233)
Charge-offs	(40)	(76)	(153)
Recoveries	4	0	0
Transfers	4	4	30
Other	5	5	4
Ending balance	71	161	319
Multifamily [Member] | Consolidated Trusts [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	203	220	437
Provision (benefit) for loan losses	(27)	(13)	(187)
Charge-offs	(3)	0	0
Recoveries	0	0	0
Transfers	(4)	(4)	(30)
Other	2	0	0
Ending balance	$ 171	$ 203	$ 220

Allowance for Loan Losses and T

Allowance for Loan Losses and Total Recorded Investment in HFI Loans (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	$ 25,517	$ 31,375
Allowance for loan losses for collectively reserved loans	2,434	4,166
Total allowance for loan losses	27,951	35,541	$ 43,846	$ 58,795
Recorded investment in individually impaired loans	172,169	188,186
Recorded investment in collectively reserved loans	2,863,543	2,859,608
Total recorded investment in loans	3,035,712	3,047,794
Single-Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	25,437	31,200
Allowance for loan losses for collectively reserved loans	2,272	3,977
Total allowance for loan losses	27,709	35,177	43,307	57,687
Recorded investment in individually impaired loans	171,161	186,377
Recorded investment in collectively reserved loans	2,664,377	2,672,184
Total recorded investment in loans	2,835,538	2,858,561
Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	80	175
Allowance for loan losses for collectively reserved loans	162	189
Total allowance for loan losses	242	364	$ 539	$ 1,108
Recorded investment in individually impaired loans	1,008	1,809
Recorded investment in collectively reserved loans	199,166	187,424
Total recorded investment in loans	$ 200,174	$ 189,233

Investments in Securities Tradi

Investments in Securities Trading 1 (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	$ 39,908	$ 31,504
Mortgage-related securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	10,423	12,038
Fannie Mae [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	4,813	4,940
Freddie Mac [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	1,314	1,369
Ginnie Mae [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	426	166
Alt-A private-label securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	436	920
Subprime private-label securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	644	1,307
CMBS [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	2,341	2,515
Mortgage revenue bonds [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	449	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	$ 29,485	$ 19,466

Investments in Securities Tra80

Investments in Securities Trading 2 (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]
Net trading gains (losses)	$ (368)	$ 485	$ 260
Net trading gains (losses) recognized in the period related to securities still held at period end	$ (453)	$ 420	$ 297

Investments in Securities Avail

Investments in Securities Available-for-sale Securities 1 (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]
Gross realized gains	$ 1,066	$ 569	$ 1,632
Gross realized losses	70	5	979
Total proceeds (excludes initial sale of securities from new portfolio securitizations)	$ 8,023	$ 3,265	$ 15,157

Investments in Securities Ava82

Investments in Securities Available-for-sale Securities 2 (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	$ 18,141	$ 27,413
Gross Unrealized Gains	2,170	3,448
Gross unrealized losses - OTTI	(39)	(55)
Gross unrealized losses, other	(42)	(152)
Available-for-sale securities	20,230	30,654
Fannie Mae [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	4,008	5,330
Gross Unrealized Gains	243	328
Gross unrealized losses - OTTI	0	0
Gross unrealized losses, other	(30)	(19)
Available-for-sale securities	4,221	5,639
Freddie Mac [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	4,000	5,100
Gross Unrealized Gains	299	428
Gross unrealized losses - OTTI	0	0
Gross unrealized losses, other	0	0
Available-for-sale securities	4,299	5,528
Ginnie Mae [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	343	416
Gross Unrealized Gains	48	60
Gross unrealized losses - OTTI	0	0
Gross unrealized losses, other	0	0
Available-for-sale securities	391	476
Alt-A private-label securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	2,029	4,638
Gross Unrealized Gains	653	1,055
Gross unrealized losses - OTTI	(4)	(15)
Gross unrealized losses, other	0	0
Available-for-sale securities	2,678	5,678
Subprime private-label securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	2,526	4,103
Gross Unrealized Gains	759	1,161
Gross unrealized losses - OTTI	0	(9)
Gross unrealized losses, other	(4)	(15)
Available-for-sale securities	3,281	5,240
CMBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	1,235	1,341
Gross Unrealized Gains	20	56
Gross unrealized losses - OTTI	0	0
Gross unrealized losses, other	0	0
Available-for-sale securities	1,255	1,397
Mortgage revenue bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	2,639	3,859
Gross Unrealized Gains	99	177
Gross unrealized losses - OTTI	(29)	(8)
Gross unrealized losses, other	(8)	(5)
Available-for-sale securities	2,701	4,023
Other mortgage-related securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total amortized cost	1,361	2,626
Gross Unrealized Gains	49	183
Gross unrealized losses - OTTI	(6)	(23)
Gross unrealized losses, other	0	(113)
Available-for-sale securities	$ 1,404	$ 2,673

Investments in Securities Ava83

Investments in Securities Available-for-sale Securities 3 (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Consecutive Months, Gross Unrealized Losses	$ (50)	$ (4)
Less Than 12 Consecutive Months, Fair Value	1,552	339
12 Consecutive Months or Longer, Gross Unrealized Losses	(31)	(203)
12 Consecutive Months or Longer, Fair Value	658	2,375
Fannie Mae [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Consecutive Months, Gross Unrealized Losses	(8)	0
Less Than 12 Consecutive Months, Fair Value	659	113
12 Consecutive Months or Longer, Gross Unrealized Losses	(22)	(19)
12 Consecutive Months or Longer, Fair Value	491	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	26	171
12 Consecutive Months or Longer, Gross Unrealized Losses	(3)	(13)
12 Consecutive Months or Longer, Fair Value	54	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	12	0
12 Consecutive Months or Longer, Gross Unrealized Losses	(4)	(24)
12 Consecutive Months or Longer, Fair Value	91	460
Mortgage revenue bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Consecutive Months, Gross Unrealized Losses	(35)	(2)
Less Than 12 Consecutive Months, Fair Value	631	47
12 Consecutive Months or Longer, Gross Unrealized Losses	(2)	(11)
12 Consecutive Months or Longer, Fair Value	22	155
Other mortgage-related securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Consecutive Months, Gross Unrealized Losses	(6)	0
Less Than 12 Consecutive Months, Fair Value	224	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	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]
Other than Temporary Impairments, Amount	$ 196	$ 90	$ 64

Investments in Securities Oth85

Investments in Securities Other-than-temporary Impairments 2 (Details) $ in Millions	Dec. 31, 2015USD ($)
Subprime private-label securities [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	$ 4,367
Weighted average collateral default (percent)	41.20%
Weighted average collateral severities (percent)	58.80%
Weighted average voluntary prepayment rates (percent)	2.70%
Average credit enhancement (percent)	18.20%
Alt-A Option ARM [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	$ 434
Weighted average collateral default (percent)	28.20%
Weighted average collateral severities (percent)	34.40%
Weighted average voluntary prepayment rates (percent)	7.50%
Average credit enhancement (percent)	3.60%
Alt-A Fixed Rate [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	$ 817
Weighted average collateral default (percent)	12.00%
Weighted average collateral severities (percent)	45.00%
Weighted average voluntary prepayment rates (percent)	11.60%
Average credit enhancement (percent)	7.20%
Alt-A Variable Rate [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	$ 805
Weighted average collateral default (percent)	20.40%
Weighted average collateral severities (percent)	37.30%
Weighted average voluntary prepayment rates (percent)	8.70%
Average credit enhancement (percent)	8.70%
Alt-A Hybrid Rate [Member]
UPB and Modeled Attributes [Line Items]
Unpaid principal balance	$ 987
Weighted average collateral default (percent)	8.60%
Weighted average collateral severities (percent)	33.10%
Weighted average voluntary prepayment rates (percent)	12.50%
Average credit enhancement (percent)	4.30%

Investments in Securities Oth86

Investments in Securities Other-than-temporary Impairments 3 (Details) - Available-for-sale securities [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance, beginning of period	$ 5,260	$ 7,904
Additions for the credit component on debt securities for which OTTI was not previously recognized	0	1
Additions for the credit component on debt securities for which OTTI was previously recognized	8	58
Reductions for securities no longer in portfolio at period end	(1,171)	(904)
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	(1,492)	(1,453)
Reductions for amortization resulting from changes in cash flows expected to be collected over the remaining life of the securities	(184)	(346)
Balance, end of period	$ 2,421	$ 5,260

Investments in Securities Matur

Investments in Securities Maturity Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	$ 18,141	$ 27,413
Total fair value	20,230	30,654
One Year or Less, Amortized Cost	290
One Year or Less, Fair Value	292
After One Year through Five Years, Amortized Cost	1,357
After One Year through Five Years, Fair Value	1,387
After Five Years through Ten Years, Amortized Cost	716
After Five Years through Ten Years, Fair Value	763
After Ten Years, Amortized Cost	15,778
After Ten Years, Fair Value	$ 17,788
Weighted average yield (percent)	4.94%
One Year or Less, Weighted Average Yield	4.36%
After One Year through Five Years, Weighted Average Yield	4.51%
After Five Years through Ten Years, Weighted Average Yield	6.28%
After Ten Years, Weighted Average Yield	4.93%
Fannie Mae [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	$ 4,008	5,330
Total fair value	4,221	5,639
One Year or Less, Amortized Cost	0
One Year or Less, Fair Value	0
After One Year through Five Years, Amortized Cost	160
After One Year through Five Years, Fair Value	164
After Five Years through Ten Years, Amortized Cost	114
After Five Years through Ten Years, Fair Value	123
After Ten Years, Amortized Cost	3,734
After Ten Years, Fair Value	3,934
Freddie Mac [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	4,000	5,100
Total fair value	4,299	5,528
One Year or Less, Amortized Cost	1
One Year or Less, Fair Value	1
After One Year through Five Years, Amortized Cost	185
After One Year through Five Years, Fair Value	192
After Five Years through Ten Years, Amortized Cost	310
After Five Years through Ten Years, Fair Value	337
After Ten Years, Amortized Cost	3,504
After Ten Years, Fair Value	3,769
Ginnie Mae [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	343	416
Total fair value	391	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	61
After Five Years through Ten Years, Fair Value	68
After Ten Years, Amortized Cost	281
After Ten Years, Fair Value	322
Alt-A private-label securities [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	2,029	4,638
Total fair value	2,678	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	2,029
After Ten Years, Fair Value	2,678
Subprime private-label securities [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	2,526	4,103
Total fair value	3,281	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	2,526
After Ten Years, Fair Value	3,281
CMBS [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	1,235	1,341
Total fair value	1,255	1,397
One Year or Less, Amortized Cost	278
One Year or Less, Fair Value	280
After One Year through Five Years, Amortized Cost	899
After One Year through Five Years, Fair Value	917
After Five Years through Ten Years, Amortized Cost	0
After Five Years through Ten Years, Fair Value	0
After Ten Years, Amortized Cost	58
After Ten Years, Fair Value	58
Mortgage revenue bonds [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	2,639	3,859
Total fair value	2,701	4,023
One Year or Less, Amortized Cost	11
One Year or Less, Fair Value	11
After One Year through Five Years, Amortized Cost	112
After One Year through Five Years, Fair Value	113
After Five Years through Ten Years, Amortized Cost	202
After Five Years through Ten Years, Fair Value	205
After Ten Years, Amortized Cost	2,314
After Ten Years, Fair Value	2,372
Other mortgage-related securities [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	1,361	2,626
Total fair value	1,404	$ 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	29
After Five Years through Ten Years, Fair Value	30
After Ten Years, Amortized Cost	1,332
After Ten Years, Fair Value	$ 1,374

Financial Guarantees and Maximu

Financial Guarantees and Maximum Recovery (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Financial Guarantees and Maximum Recovery [Line Items]
Maximum exposure	$ 31,573	$ 35,965
Guaranty obligation	329	382
Maximum recovery	11,726	14,222
Unconsolidated VIEs [Member] | Unconsolidated Fannie Mae MBS [Member]
Financial Guarantees and Maximum Recovery [Line Items]
Maximum exposure	15,069	17,184
Guaranty obligation	194	214
Maximum recovery	8,857	9,775
Unconsolidated VIEs [Member] | Other guaranty arrangements [Member]
Financial Guarantees and Maximum Recovery [Line Items]
Maximum exposure	16,504	18,781
Guaranty obligation	135	168
Maximum recovery	$ 2,869	$ 4,447
Minimum [Member]
Financial Guarantees and Maximum Recovery [Line Items]
Remaining contractual terms of our guarantee	P11D
Maximum [Member]
Financial Guarantees and Maximum Recovery [Line Items]
Remaining contractual terms of our guarantee	P37Y

Acquired Property, Net (Details

Acquired Property, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Acquired Property [Roll Forward]
Beginning balance - Acquired property	$ 11,442	$ 12,307	$ 11,158
Additions	9,382	13,100	16,092
Disposals	(13,343)	(13,965)	(14,943)
Ending balance - Acquired property	7,481	11,442	12,307
Real Estate Owned Valuation Allowance [Roll Forward]
Beginning balance - Valuation allowance	(824)	(686)	(669)
Decrease (Increase) in Valuation allowance	109	(138)	(17)
Ending balance - Valuation allowance	(715)	(824)	(686)
Acquired property, net	6,766	10,618	11,621
Foreclosed Properties Acquired Held-for-Use, Net	$ 85	$ 135	$ 256

Short-term Debt (Details)

Short-term Debt (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Short-term Borrowings [Line Items]
Federal funds purchased and securities sold under agreements to repurchase	$ 62,000,000	$ 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	$ 71,950,000,000	$ 106,572,000,000
Short-term debt, weighted-average interest rate	0.26%	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	$ 71,007,000,000	$ 105,012,000,000
Short-term debt, weighted-average interest rate	0.26%	0.11%
Consolidated Trusts [Member]
Short-term Borrowings [Line Items]
Short-term debt, outstanding	$ 943,000,000	$ 1,560,000,000
Short-term debt, weighted-average interest rate	0.19%	0.09%

Long-term Debt (Details)

Long-term Debt (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 3,125,721	$ 3,115,583
Long-term debt, weighted-average interest rate	2.88%	2.93%
Fannie Mae [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 315,128	$ 355,431
Long-term debt, weighted-average interest rate	2.41%	2.24%
Net unamortized discount, fair value adjustments and other cost basis adjustments	$ 3,200	$ 4,100
Fannie Mae [Member] | Senior Fixed [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 278,826	$ 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	$ 154,057	$ 173,010
Long-term debt, weighted-average interest rate	2.49%	2.41%
Fannie Mae [Member] | Senior Fixed Medium-Term Notes [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 96,997	$ 114,556
Long-term debt, weighted-average interest rate	1.53%	1.42%
Fannie Mae [Member] | Senior Fixed Other Debt [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 27,772	$ 32,941
Long-term debt, weighted-average interest rate	4.88%	4.65%
Fannie Mae [Member] | Senior Floating [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 31,923	$ 30,873
Long-term debt, weighted-average interest rate	1.58%	0.81%
Fannie Mae [Member] | Senior Floating Medium-Term Notes [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 20,791	$ 24,469
Long-term debt, weighted-average interest rate	0.27%	0.15%
Fannie Mae [Member] | Senior Floating Connecticut Avenue Security [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 10,764	$ 6,041
Long-term debt, weighted-average interest rate	3.84%	2.97%
Fannie Mae [Member] | Senior Floating Other Debt [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 368	$ 363
Long-term debt, weighted-average interest rate	10.46%	8.71%
Fannie Mae [Member] | Subordinated Debentures [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 4,227	$ 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	$ 152	$ 202
Long-term debt, weighted-average interest rate	1.47%	1.90%
Consolidated Trusts [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 2,810,593	$ 2,760,152
Long-term debt, weighted-average interest rate	2.94%	3.02%
Minimum [Member] | Fannie Mae [Member]
Long-Term Debt [Line Items]
Medium-term notes original contractual maturity	1 year	1 year
Maximum [Member] | Fannie Mae [Member]
Long-Term Debt [Line Items]
Medium-term notes original contractual maturity	10 years	10 years

Short-Term Borrowings and Lon92

Short-Term Borrowings and Long-Term Debt Characteristics of Debt (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Long-Term Debt by Year of Maturity [Abstract]
Total long-term debt	$ 3,125,721	$ 3,115,583
Fannie Mae [Member]
Long-Term Debt [Line Items]
Face amount	389,400	464,600
Long-Term Debt by Year of Maturity [Abstract]
2,016	52,829
2,017	76,970
2,018	60,555
2,019	29,656
2,020	30,129
Thereafter	64,989
Total long-term debt	315,128	355,431
Net unamortized discount, fair value adjustments and other cost basis adjustments	3,200	4,100
Fannie Mae [Member] | Zero-Coupon Debt [Member]
Long-Term Debt [Line Items]
Face amount	$ 82,100	$ 116,700
Effective interest rate	1.26%	0.77%
Fannie Mae [Member] | Callable [Member]
Long-Term Debt [Line Items]
Outstanding debt	$ 96,200	$ 115,000
Consolidated Trusts [Member]
Long-Term Debt by Year of Maturity [Abstract]
Total long-term debt	2,810,593	$ 2,760,152
Earlier of Contractual Maturity or Next Call Date [Member]
Long-Term Debt by Year of Maturity [Abstract]
Total long-term debt	3,125,721
Earlier of Contractual Maturity or Next Call Date [Member] | Fannie Mae [Member]
Long-Term Debt by Year of Maturity [Abstract]
2,016	143,970
2,017	69,351
2,018	32,832
2,019	19,036
2,020	16,658
Thereafter	33,281
Total long-term debt	315,128
Earlier of Contractual Maturity or Next Call Date [Member] | Consolidated Trusts [Member]
Long-Term Debt by Year of Maturity [Abstract]
Total long-term debt	$ 2,810,593

Derivative Instruments Deriva93

Derivative Instruments Derivatives 1 - Notional and FV Position (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Asset Derivatives [Abstract]
Notional amount	$ 175,667	$ 183,204
Derivative asset, estimated fair value	894	1,485
Netting adjustment	(4,024)	(5,186)
Derivative Liabilities [Abstract]
Notional amount	375,704	408,714
Derivative liability, estimated fair value	(424)	(614)
Netting adjustment	8,650	10,194
Table Footnote [Abstract]
Cash collateral posted for derivative instruments	4,900	5,300
Cash collateral received for derivative instruments	314	245
Risk management derivatives [Member]
Asset Derivatives [Abstract]
Notional amount	113,355	128,628
Derivative asset, estimated fair value	4,020	5,667
Accrued interest receivable	758	749
Netting adjustment	(4,024)	(5,186)
Total net risk management derivatives - Asset	754	1,230
Derivative Liabilities [Abstract]
Notional amount	312,573	344,264
Derivative liability, estimated fair value	(7,939)	(9,451)
Accrued interest payable	(977)	(1,013)
Netting adjustment	8,650	10,194
Total net risk management derivatives - Liability	(266)	(270)
Risk management derivatives [Member] | Pay-fixed Swap [Member]
Asset Derivatives [Abstract]
Notional amount	33,154	41,965
Derivative asset, estimated fair value	267	733
Derivative Liabilities [Abstract]
Notional amount	123,106	123,557
Derivative liability, estimated fair value	(6,920)	(7,125)
Risk management derivatives [Member] | Receive-fixed Swap [Member]
Asset Derivatives [Abstract]
Notional amount	59,796	67,629
Derivative asset, estimated fair value	3,436	4,486
Derivative Liabilities [Abstract]
Notional amount	143,209	157,272
Derivative liability, estimated fair value	(753)	(1,302)
Risk management derivatives [Member] | Basis Swap [Member]
Asset Derivatives [Abstract]
Notional amount	1,864	5,769
Derivative asset, estimated fair value	141	123
Derivative Liabilities [Abstract]
Notional amount	17,100	7,100
Derivative liability, estimated fair value	(15)	(2)
Risk management derivatives [Member] | Foreign Currency Swap [Member]
Asset Derivatives [Abstract]
Notional amount	295	344
Derivative asset, estimated fair value	95	144
Derivative Liabilities [Abstract]
Notional amount	258	273
Derivative liability, estimated fair value	(52)	(30)
Risk management derivatives [Member] | Pay-fixed Swaption [Member]
Asset Derivatives [Abstract]
Notional amount	7,050	11,100
Derivative asset, estimated fair value	45	57
Derivative Liabilities [Abstract]
Notional amount	14,950	26,525
Derivative liability, estimated fair value	(26)	(175)
Risk management derivatives [Member] | Receive-fixed Swaption [Member]
Asset Derivatives [Abstract]
Notional amount	2,000	750
Derivative asset, estimated fair value	8	96
Derivative Liabilities [Abstract]
Notional amount	13,950	29,525
Derivative liability, estimated fair value	(171)	(816)
Risk management derivatives [Member] | Other [Member]
Asset Derivatives [Abstract]
Notional amount	9,196	1,071
Derivative asset, estimated fair value	28	28
Derivative Liabilities [Abstract]
Notional amount	0	12
Derivative liability, estimated fair value	(2)	(1)
Mortgage commitment derivatives [Member]
Asset Derivatives [Abstract]
Notional amount	62,312	54,576
Derivative asset, estimated fair value	140	255
Netting adjustment	0	0
Derivative Liabilities [Abstract]
Notional amount	63,131	64,450
Derivative liability, estimated fair value	(158)	(344)
Netting adjustment	0	0
Mortgage commitment derivatives [Member] | Mortgage Commitments to Purchase Whole Loans [Member]
Asset Derivatives [Abstract]
Notional amount	4,815	6,157
Derivative asset, estimated fair value	9	28
Derivative Liabilities [Abstract]
Notional amount	2,960	428
Derivative liability, estimated fair value	(9)	0
Mortgage commitment derivatives [Member] | Forward Contracts to Purchase Mortgage-related Securities [Member]
Asset Derivatives [Abstract]
Notional amount	31,273	43,533
Derivative asset, estimated fair value	66	223
Derivative Liabilities [Abstract]
Notional amount	19,418	6,112
Derivative liability, estimated fair value	(57)	(8)
Mortgage commitment derivatives [Member] | Forward Contracts to Sell Mortgage-related Securities [Member]
Asset Derivatives [Abstract]
Notional amount	26,224	4,886
Derivative asset, estimated fair value	65	4
Derivative Liabilities [Abstract]
Notional amount	40,753	57,910
Derivative liability, estimated fair value	$ (92)	$ (336)

Derivative Instruments (Narrati

Derivative Instruments (Narratives) (Details) - USD ($) $ in Millions	Dec. 31, 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	$ 2,400	$ 2,600
Fair value of collateral posted	2,200	2,400
Additional collateral required to immediately settle our positions if the credit-risk-related contingent features were triggered	$ 257	$ 269

Derivative Instruments Deriva95

Derivative Instruments Derivatives 2 - FV Gains and Losses (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net									$ (1,513)	$ (5,764)	$ 3,280
Accrual of periodic settlements	$ 5,077	$ 5,588	$ 5,677	$ 5,067	$ 5,142	$ 5,184	$ 4,904	$ 4,738	21,409	19,968	22,404
Risk management derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net									(1,120)	(4,624)	2,779
Risk management derivatives [Member] | Pay-fixed Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net									(746)	(7,703)	14,393
Accrual of periodic settlements									(3,602)	(3,712)	(4,463)
Risk management derivatives [Member] | Receive-fixed Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net									625	4,229	(10,721)
Accrual of periodic settlements									2,603	2,600	3,632
Risk management derivatives [Member] | Basis Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net									4	85	(115)
Risk management derivatives [Member] | Foreign Currency Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net									(60)	27	(101)
Risk management derivatives [Member] | Pay-fixed Swaption [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net									135	(4)	(238)
Risk management derivatives [Member] | Receive-fixed Swaption [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net									(93)	(197)	307
Risk management derivatives [Member] | Other [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net									(25)	1	21
Accrual of periodic settlements									39	50	64
Mortgage commitment derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net									$ (393)	$ (1,140)	$ 501

Income Taxes Provision (Benefit

Income Taxes Provision (Benefit) for Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Provision (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Current income tax provision (benefit)									$ (271)	$ 1,879	$ 3,067
Deferred income tax provision (benefit)									5,524	5,062	(48,482)
Provision (benefit) for federal income taxes	$ 1,103	$ 1,070	$ 2,210	$ 870	$ 818	$ 1,787	$ 1,752	$ 2,584	$ 5,253	$ 6,941	$ (45,415)
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Statutory corporate tax rate									35.00%	35.00%	35.00%
Equity investments in affordable housing projects									(2.60%)	(1.80%)	(1.50%)
Other									0.90%	1.40%	0.00%
Valuation allowance									(0.90%)	(1.80%)	(151.30%)
Effective tax rate									32.40%	32.80%	(117.80%)
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount											$ (58,300)
Amended Tax Return [Member]
Income Tax note [Line Items]
Income Taxes Receivable, Current	$ 1,400								$ 1,400
Change in Deferred Tax Assets									$ (1,400)

Income Taxes Deferred Tax Asset

Income Taxes Deferred Tax Assets and Liabilities (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Deferred Tax Assets, Operating Loss Carryforwards	$ 0
Deferred Tax Assets, Tax Credit Carryforwards, Partnership, Net of Uncertain Tax Position Liabilities	3,400,000,000
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax	308,000,000
Deferred tax assets:
Mortgage and mortgage-related assets	16,956,000,000	$ 16,250,000,000
Allowance for loan losses and basis in acquired property, net	11,760,000,000	17,435,000,000
Debt and derivative instruments	3,512,000,000	4,254,000,000
Partnership credits	3,402,000,000	2,918,000,000
Partnership and other equity investments	745,000,000	934,000,000
Other, net	1,543,000,000	1,699,000,000
Total deferred tax assets	37,918,000,000	43,490,000,000
Deferred tax liabilities:
Unrealized gains on AFS securities, net	731,000,000	1,134,000,000
Total deferred tax liabilities	731,000,000	1,134,000,000
Valuation allowance	0	(150,000,000)
Net deferred tax assets	$ 37,187,000,000	$ 42,206,000,000

Income Taxes Unrecognized Tax B

Income Taxes Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits as of January 1	$ 213	$ 514	$ 648
Gross decreases- tax positions in prior years	(213)	(301)	(134)
Unrecognized tax benefits as of December 31	$ 0	213	514
Unrecognized Tax Benefit Resulting in Tax Credits and/or Net Operating Loss Carryforward		$ 91	$ 220

Loss Per Share (Details)

Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share [Abstract]
Net income	$ 2,467	$ 1,960	$ 4,640	$ 1,888	$ 1,312	$ 3,905	$ 3,667	$ 5,325	$ 10,955	$ 14,209	$ 83,982
Less: Net income attributable to noncontrolling interest	(1)	0	0	0	0	0	(1)	0	(1)	(1)	(19)
Net income attributable to Fannie Mae	2,466	1,960	4,640	1,888	1,312	3,905	3,666	5,325	10,954	14,208	83,963
Dividends distributed or available for distribution to senior preferred stockholder	(2,859)	(2,202)	(4,359)	(1,796)	(1,920)	(3,999)	(3,712)	(5,692)	(11,216)	(15,323)	(85,419)
Net loss attributable to common stockholders (Note 11)	$ (393)	$ (242)	$ 281	$ 92	$ (608)	$ (94)	$ (46)	$ (367)	$ (262)	$ (1,115)	$ (1,456)
Weighted-average common shares outstanding: Basic and Diluted					5,762	5,762	5,762	5,762	5,762	5,762	5,762
Loss per share: Basic and Diluted (in dollars per share)	$ (0.07)	$ (0.04)	$ 0.05	$ 0.02	$ (0.11)	$ (0.02)	$ (0.01)	$ (0.06)	$ (0.05)	$ (0.19)	$ (0.25)
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

Segment Reporting (Narrative) (

Segment Reporting (Narrative) (Details)	12 Months Ended
	Dec. 31, 2015segments
Segment Reporting [Abstract]
Number of Reportable Segments	3

Segment Reporting (Details)

Segment Reporting (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Net interest income (loss)	$ 5,077	$ 5,588	$ 5,677	$ 5,067	$ 5,142	$ 5,184	$ 4,904	$ 4,738	$ 21,409	$ 19,968	$ 22,404
Benefit for credit losses	(255)	1,550	(1,033)	533	466	1,085	1,639	774	795	3,964	8,949
Net interest income after benefit for credit losses	4,822	7,138	4,644	5,600	5,608	6,269	6,543	5,512	22,204	23,932	31,353
Guaranty fee income (expense)									128	175	205
Investment gains (losses), net	181	299	514	342	187	171	483	95	1,336	936	1,127
Fair value gains (losses), net	135	(2,589)	2,606	(1,919)	(2,502)	(207)	(934)	(1,190)	(1,767)	(4,833)	2,959
Debt extinguishment gains, net									8	66	131
Gains (losses) from partnership investments									244	269	517
Fee and other income (expense)									1,220	5,712	3,725
Administrative expenses	(686)	(952)	(689)	(723)	(702)	(706)	(697)	(672)	(3,050)	(2,777)	(2,545)
Foreclosed property income (expense)	(477)	(497)	(182)	(473)	(369)	(249)	214	262	(1,629)	(142)	2,839
TCCA fees	(429)	(413)	(397)	(382)	(367)	(351)	(335)	(322)	(1,621)	(1,375)	(1,001)
Other expenses									(865)	(813)	(743)
Income before federal income taxes	3,570	3,030	6,850	2,758	2,130	5,692	5,419	7,909	16,208	21,150	38,567
Benefit (provision) for federal income taxes	(1,103)	(1,070)	(2,210)	(870)	(818)	(1,787)	(1,752)	(2,584)	(5,253)	(6,941)	45,415
Net income	2,467	1,960	4,640	1,888	1,312	3,905	3,667	5,325	10,955	14,209	83,982
Less: Net (income) loss attributable to noncontrolling interest	(1)	0	0	0	0	0	(1)	0	(1)	(1)	(19)
Net income attributable to Fannie Mae	2,466	$ 1,960	$ 4,640	$ 1,888	$ 1,312	$ 3,905	$ 3,666	$ 5,325	10,954	14,208	83,963
US Treasury [Member]
Segment Reporting Information [Line Items]
TCCA fees	$ (429)								(1,621)	(1,375)	(1,001)
Operating Segments [Member] | Single-Family [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)									184	6	205
Benefit for credit losses									688	3,850	8,469
Net interest income after benefit for credit losses									872	3,856	8,674
Guaranty fee income (expense)									12,476	11,702	10,468
Investment gains (losses), net									(2)	(1)	3
Fair value gains (losses), net									(11)	(19)	(10)
Debt extinguishment gains, net									0	0	0
Gains (losses) from partnership investments									(39)	(31)	0
Fee and other income (expense)									666	624	630
Administrative expenses									(2,053)	(1,830)	(1,706)
Foreclosed property income (expense)									(1,723)	(225)	2,736
Other expenses									(942)	(726)	(628)
Income before federal income taxes									7,623	11,975	19,166
Benefit (provision) for federal income taxes									(2,491)	(3,496)	29,110
Net income									5,132	8,479	48,276
Less: Net (income) loss attributable to noncontrolling interest									0	0	0
Net income attributable to Fannie Mae									5,132	8,479	48,276
Operating Segments [Member] | Multifamily [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)									(92)	(79)	(74)
Benefit for credit losses									107	114	480
Net interest income after benefit for credit losses									15	35	406
Guaranty fee income (expense)									1,439	1,297	1,217
Investment gains (losses), net									33	57	21
Fair value gains (losses), net									0	0	0
Debt extinguishment gains, net									0	0	0
Gains (losses) from partnership investments									282	299	498
Fee and other income (expense)									265	166	182
Administrative expenses									(361)	(306)	(280)
Foreclosed property income (expense)									94	83	103
Other expenses									(13)	(10)	(2)
Income before federal income taxes									1,754	1,621	2,145
Benefit (provision) for federal income taxes									(247)	(158)	7,924
Net income									1,507	1,463	10,069
Less: Net (income) loss attributable to noncontrolling interest									0	0	0
Net income attributable to Fannie Mae									1,507	1,463	10,069
Operating Segments [Member] | Capital Markets [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)									5,828	7,243	9,764
Benefit for credit losses									0	0	0
Net interest income after benefit for credit losses									5,828	7,243	9,764
Guaranty fee expense									(863)	(955)	(1,115)
Investment gains (losses), net									5,539	6,378	4,847
Fair value gains (losses), net									(2,049)	(5,476)	3,148
Debt extinguishment gains, net									(37)	35	27
Gains (losses) from partnership investments									0	0	0
Fee and other income (expense)									209	4,894	3,010
Administrative expenses									(636)	(641)	(559)
Foreclosed property income (expense)									0	0	0
Other expenses									8	(77)	20
Income before federal income taxes									7,999	11,401	19,142
Benefit (provision) for federal income taxes									(2,515)	(3,287)	8,381
Net income									5,484	8,114	27,523
Less: Net (income) loss attributable to noncontrolling interest									0	0	0
Net income attributable to Fannie Mae									5,484	8,114	27,523
Operating Segments [Member] | US Treasury [Member] | Single-Family [Member]
Segment Reporting Information [Line Items]
TCCA fees									(1,621)	(1,375)	(1,001)
Reconciling Items [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)									15,489	12,798	12,509
Benefit for credit losses									0	0	0
Net interest income after benefit for credit losses									15,489	12,798	12,509
Guaranty fee expense									(12,924)	(11,869)	(10,365)
Investment gains (losses), net									(4,234)	(5,498)	(3,744)
Fair value gains (losses), net									293	662	(179)
Debt extinguishment gains, net									45	31	104
Gains (losses) from partnership investments									1	1	19
Fee and other income (expense)									80	28	(97)
Administrative expenses									0	0	0
Foreclosed property income (expense)									0	0	0
Other expenses									82	0	(133)
Income before federal income taxes									(1,168)	(3,847)	(1,886)
Benefit (provision) for federal income taxes									0	0	0
Net income									(1,168)	(3,847)	(1,886)
Less: Net (income) loss attributable to noncontrolling interest									(1)	(1)	(19)
Net income attributable to Fannie Mae									$ (1,169)	$ (3,848)	$ (1,905)

Segment Reporting (Assets) (Det

Segment Reporting (Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 3,221,917	$ 3,248,176	$ 3,270,108
Consolidated Trusts [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	2,850,000	2,830,000	2,810,000
Operating Segments [Member] | Single-Family [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	34,911	43,512	41,206
Operating Segments [Member] | Multifamily [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	9,947	9,281	10,848
Operating Segments [Member] | Capital Markets [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	432,689	510,848	596,436
Reconciling Items [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 2,744,370	$ 2,684,535	$ 2,621,618

Equity Narratives (Details)

Equity Narratives (Details)	Sep. 08, 2008USD ($)$ / shares	Sep. 08, 2008USD ($)$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2014USD ($)shares	Dec. 31, 2013USD ($)	Dec. 31, 2016USD ($)	Sep. 07, 2008$ / shares
Class of Stock [Line Items]
Common stock outstanding | shares			1,158,082,750	1,158,082,750
Percentage of common shares attributable to warrants issued to Treasury as a percentage to total diluted common shares upon exercise of the right			79.90%
Aggregate funding received from US Treasury pursuant to the senior preferred stock purchase agreement			$ 116,100,000,000
Dividends declared on our senior preferred stock			10,278,000,000	$ 20,594,000,000	$ 82,452,000,000
Annual reduction of capital reserve from 2013 to 2018 based on the Senior Preferred Stock Purchase Agreement, Amendment			600,000,000
Capital reserve amount on January 2018			$ 0
Convertible Series 2004-1 Preferred Stock [Member]
Class of Stock [Line Items]
Conversion price per share | $ / shares			$ 94.31
Conversion rate			1,060.3329
Preferred stock redemption price per share | $ / shares			$ 105,000
Series 2008-2 Senior Preferred Stock [Member]
Class of Stock [Line Items]
Senior preferred stock liquidation preference per share | $ / shares	$ 1,000	$ 1,000	$ 117,149
Shares of variable liquidation preference senior preferred stock issued | shares		1,000,000
Aggregate liquidation preference of senior preferred stock	$ 1,000,000,000	$ 1,000,000,000
Value assigned to Treasury's commitment and recorded as a reduction to additional paid-in-capital	$ 4,500,000,000
Dividends declared on our senior preferred stock			$ 10,300,000,000	20,600,000,000	$ 82,500,000,000
Preferred Stock Covenant Maximum Fair Market Value of assets and properties per transaction			250,000,000
Preferred Stock, Covenant, Maximum Aggregate Debt Amount, Current Period			$ 563,600,000,000
Preferred Stock, Covenant, Current Period Debt v.s. Maximum Mortgage Assets Allowed at Prior Year End, Maximum Ratio			120.00%
Preferred Stock, Covenant, Maximum Mortgage Assets			$ 399,200,000,000
Preferred Stock, Covenant, Mortgage Assets at Year End, Maximum Ratio of Proceeding Year End			85.00%
Preferred Stock, Covenant, Minimum Mortgage Assets			$ 250,000,000,000
Minimum [Member] | Series O Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock redemption price per share | $ / shares			$ 50
Minimum [Member] | Series 2008-2 Senior Preferred Stock [Member]
Class of Stock [Line Items]
FHFA Request, Covenant, Mortgage Assets at Year End, Minimum Ratio of Proceeding Year End			90.00%
Maximum [Member] | Series O Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock redemption price per share | $ / shares			$ 52.5
Maximum [Member] | Series 2008-2 Senior Preferred Stock [Member]
Class of Stock [Line Items]
FHFA Request, Covenant, Mortgage Assets at Year End, Minimum Ratio of Proceeding Year End			95.00%
US Treasury [Member]
Class of Stock [Line Items]
Percentage of common shares attributable to warrants issued to Treasury as a percentage to total diluted common shares upon exercise of the right			79.90%				79.90%
Aggregate liquidation preference of senior preferred stock			$ 117,100,000,000
Aggregate funding received from US Treasury pursuant to the senior preferred stock purchase agreement			116,100,000,000	116,100,000,000
Capital reserve amount for the fiscal year based on the amended Senior Preferred Stock Purchase agreement			1,800,000,000	$ 2,400,000,000
Annual reduction of capital reserve from 2013 to 2018 based on the Senior Preferred Stock Purchase Agreement, Amendment			600,000,000
Common stock warrant exercise price per share | $ / shares							$ 0.00001
Initial aggregate liquidation preference of senior preferred stock held by US Treasury			1,000,000,000
Total remaining funding available from US Treasury pursuant to the senior preferred stock agreement			$ 117,600,000,000
US Treasury [Member] | Scenario, Forecast [Member]
Class of Stock [Line Items]
Capital reserve amount for the fiscal year based on the amended Senior Preferred Stock Purchase agreement						$ 1,200,000,000

Equity Schedule of Stock by Cla

Equity Schedule of Stock by Class (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2014	Sep. 08, 2008	Jun. 04, 2008	May. 22, 2008	May. 19, 2008	Dec. 14, 2007	Nov. 21, 2007
Class of Stock [Line Items]
Senior preferred stock issued, shares	1,000,000		1,000,000
Senior Preferred Stock Value	$ 117,149,000,000		$ 117,149,000,000
Senior preferred stock, shares outstanding	1,000,000		1,000,000
Preferred Stock, Shares Issued	555,374,922		555,374,922
Preferred Stock Issued, Amount	$ 19,130,000,000		$ 19,130,000,000
Preferred stock, shares outstanding	555,374,922		555,374,922
Preferred Stock Outstanding, Amount	$ 19,130,000,000		$ 19,130,000,000
Annual reduction of capital reserve from 2013 to 2018 based on the Senior Preferred Stock Purchase Agreement, Amendment	600,000,000
Capital reserve amount on January 2018	$ 0
Series 2008-2 Senior Preferred Stock [Member]
Class of Stock [Line Items]
Senior preferred stock issued, shares	1,000,000		1,000,000
Senior Preferred Stock Value	$ 117,149,000,000		$ 117,149,000,000	$ 1,000,000,000
Senior preferred stock, shares outstanding	1,000,000		1,000,000
Senior Preferred Stock, Stated Value per Share	$ 117,149			$ 1,000
Series D Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	3,000,000		3,000,000
Preferred Stock Issued, Amount	$ 150,000,000		$ 150,000,000
Preferred stock, shares outstanding	3,000,000		3,000,000
Preferred Stock Outstanding, Amount	$ 150,000,000		$ 150,000,000
Preferred Stock, Stated Value per Share	$ 50
Preferred stock, annual dividend rate (as a percent)	5.25%
Series E Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	3,000,000		3,000,000
Preferred Stock Issued, Amount	$ 150,000,000		$ 150,000,000
Preferred stock, shares outstanding	3,000,000		3,000,000
Preferred Stock Outstanding, Amount	$ 150,000,000		$ 150,000,000
Preferred Stock, Stated Value per Share	$ 50
Preferred stock, annual dividend rate (as a percent)	5.10%
Series F Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	14,000,000		14,000,000
Preferred Stock Issued, Amount	$ 690,000,000		$ 690,000,000
Preferred stock, shares outstanding	14,000,000		14,000,000
Preferred Stock Outstanding, Amount	$ 690,000,000		$ 690,000,000
Preferred Stock, Stated Value per Share	$ 50
Preferred stock, annual dividend rate (as a percent)	0.26%
Preferred Stock, Redemption Terms	P2Y
Series G Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	6,000,000		6,000,000
Preferred Stock Issued, Amount	$ 288,000,000		$ 288,000,000
Preferred stock, shares outstanding	6,000,000		6,000,000
Preferred Stock Outstanding, Amount	$ 288,000,000		$ 288,000,000
Preferred Stock, Stated Value per Share	$ 50
Preferred stock, annual dividend rate (as a percent)	0.40%
Preferred Stock, Redemption Terms	P2Y
Series H Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	8,000,000		8,000,000
Preferred Stock Issued, Amount	$ 400,000,000		$ 400,000,000
Preferred stock, shares outstanding	8,000,000		8,000,000
Preferred Stock Outstanding, Amount	$ 400,000,000		$ 400,000,000
Preferred Stock, Stated Value per Share	$ 50
Preferred stock, annual dividend rate (as a percent)	5.81%
Series I Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	6,000,000		6,000,000
Preferred Stock Issued, Amount	$ 300,000,000		$ 300,000,000
Preferred stock, shares outstanding	6,000,000		6,000,000
Preferred Stock Outstanding, Amount	$ 300,000,000		$ 300,000,000
Preferred Stock, Stated Value per Share	$ 50
Preferred stock, annual dividend rate (as a percent)	5.375%
Series L Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	7,000,000		7,000,000
Preferred Stock Issued, Amount	$ 345,000,000		$ 345,000,000
Preferred stock, shares outstanding	7,000,000		7,000,000
Preferred Stock Outstanding, Amount	$ 345,000,000		$ 345,000,000
Preferred Stock, Stated Value per Share	$ 50
Preferred stock, annual dividend rate (as a percent)	5.125%
Series M Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	9,000,000		9,000,000
Preferred Stock Issued, Amount	$ 460,000,000		$ 460,000,000
Preferred stock, shares outstanding	9,000,000		9,000,000
Preferred Stock Outstanding, Amount	$ 460,000,000		$ 460,000,000
Preferred Stock, Stated Value per Share	$ 50
Preferred stock, annual dividend rate (as a percent)	4.75%
Series N Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	5,000,000		5,000,000
Preferred Stock Issued, Amount	$ 225,000,000		$ 225,000,000
Preferred stock, shares outstanding	5,000,000		5,000,000
Preferred Stock Outstanding, Amount	$ 225,000,000		$ 225,000,000
Preferred Stock, Stated Value per Share	$ 50
Preferred stock, annual dividend rate (as a percent)	5.50%
Series O Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	50,000,000		50,000,000
Preferred Stock Issued, Amount	$ 2,500,000,000		$ 2,500,000,000
Preferred stock, shares outstanding	50,000,000		50,000,000
Preferred Stock Outstanding, Amount	$ 2,500,000,000		$ 2,500,000,000
Preferred Stock, Stated Value per Share	$ 50
Preferred stock, annual dividend rate (as a percent)	7.00%
Convertible Series 2004-1 Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	24,922		24,922
Preferred Stock Issued, Amount	$ 2,492,000,000		$ 2,492,000,000
Preferred stock, shares outstanding	24,922		24,922
Preferred Stock Outstanding, Amount	$ 2,492,000,000		$ 2,492,000,000
Preferred Stock, Stated Value per Share	$ 100,000
Preferred stock, annual dividend rate (as a percent)	5.375%
Series P Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	40,000,000		40,000,000
Preferred Stock Issued, Amount	$ 1,000,000,000		$ 1,000,000,000
Preferred stock, shares outstanding	40,000,000		40,000,000
Preferred Stock Outstanding, Amount	$ 1,000,000,000		$ 1,000,000,000
Preferred Stock, Stated Value per Share	$ 25
Preferred stock, annual dividend rate (as a percent)	4.50%
Series Q Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	15,000,000		15,000,000
Preferred Stock Issued, Amount	$ 375,000,000		$ 375,000,000
Preferred stock, shares outstanding	15,000,000		15,000,000
Preferred Stock Outstanding, Amount	$ 375,000,000		$ 375,000,000
Preferred Stock, Stated Value per Share	$ 25
Preferred stock, annual dividend rate (as a percent)	6.75%
Series R Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	21,000,000		21,000,000					1,200,000	20,000,000
Preferred Stock Issued, Amount	$ 530,000,000		$ 530,000,000					$ 30,000,000	$ 500,000,000
Preferred stock, shares outstanding	21,000,000		21,000,000
Preferred Stock Outstanding, Amount	$ 530,000,000		$ 530,000,000
Preferred Stock, Stated Value per Share	$ 25
Preferred stock, annual dividend rate (as a percent)	7.625%
Series S Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	280,000,000		280,000,000
Preferred Stock Issued, Amount	$ 7,000,000,000		$ 7,000,000,000
Preferred stock, shares outstanding	280,000,000		280,000,000
Preferred Stock Outstanding, Amount	$ 7,000,000,000		$ 7,000,000,000
Preferred Stock, Stated Value per Share	$ 25
Preferred stock, annual dividend rate (as a percent)	7.75%
Preferred Stock, Redemption Terms	P5Y
Series T Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	89,000,000		89,000,000		1,000,000	8,000,000	80,000,000
Preferred Stock Issued, Amount	$ 2,225,000,000		$ 2,225,000,000		$ 25,000,000	$ 200,000,000	$ 2,000,000,000
Preferred stock, shares outstanding	89,000,000		89,000,000
Preferred Stock Outstanding, Amount	$ 2,225,000,000		$ 2,225,000,000
Preferred Stock, Stated Value per Share	$ 25
Preferred stock, annual dividend rate (as a percent)	8.25%
Maximum [Member] | Series F Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, annual dividend rate (as a percent)	11.00%
Maximum [Member] | Series G Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, annual dividend rate (as a percent)	11.00%
Minimum [Member] | Series O Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, annual dividend rate (as a percent)	7.00%
Minimum [Member] | Series P Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, annual dividend rate (as a percent)	4.50%
Minimum [Member] | Series S Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, annual dividend rate (as a percent)	7.75%
Two-year Constant Maturity U.S. Treasury Rate [Member] | Series F Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock dividend rate, basis spread on variable rate	0.16%
Two-year Constant Maturity U.S. Treasury Rate [Member] | Series G Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock dividend rate, basis spread on variable rate	0.18%
Ten-year Constant Maturity U.S. Treasury Rate [Member] | Series O Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock dividend rate, basis spread on variable rate	2.375%
Three-Month LIBOR [Member] | Series P Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock dividend rate, basis spread on variable rate	0.75%
Three-Month LIBOR [Member] | Series S Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock dividend rate, basis spread on variable rate	4.23%
US Treasury [Member]
Class of Stock [Line Items]
Capital reserve amount for the fiscal year based on the amended Senior Preferred Stock Purchase agreement	$ 1,800,000,000		$ 2,400,000,000
Annual reduction of capital reserve from 2013 to 2018 based on the Senior Preferred Stock Purchase Agreement, Amendment	$ 600,000,000
US Treasury [Member] | Scenario, Forecast [Member]
Class of Stock [Line Items]
Capital reserve amount for the fiscal year based on the amended Senior Preferred Stock Purchase agreement		$ 1,200,000,000

Equity Accumulated Other Compre

Equity Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Equity [Abstract]
Net unrealized gains on available-for-sale securities for which we have not recorded other-than-temporary impairment, net of tax	$ 455	$ 592	$ 365
Net unrealized gains on available-for-sale securities for which we have recorded OTTI, net of tax	903	1,529	1,262
Prior service credit (cost) and actuarial gains (losses), net of amortization, net of tax	49	(388)	(424)
Accumulated other comprehensive income (loss)	$ 1,407	$ 1,733	$ 1,203

Equity Changes in AOCI (Details

Equity Changes in AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	$ 3,680
Total other comprehensive income (loss)	(326)	$ 530	$ 819
Ending balance	4,030	3,680
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	2,121	1,627
Other comprehensive income before reclassifications	(280)	722
Amounts reclassified from other comprehensive income	(483)	(228)
Total other comprehensive income (loss)	(763)	494
Ending balance	1,358	2,121	1,627
Accumulated Other Comprehensive Income (Loss), Other [Member]
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(388)	(424)
Other comprehensive income before reclassifications	17	37
Amounts reclassified from other comprehensive income	420	(1)
Total other comprehensive income (loss)	437	36
Ending balance	49	(388)	(424)
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	1,733	1,203
Other comprehensive income before reclassifications	(263)	759
Amounts reclassified from other comprehensive income	(63)	(229)
Total other comprehensive income (loss)	(326)	530
Ending balance	$ 1,407	$ 1,733	$ 1,203

Regulatory Capital Requireme107

Regulatory Capital Requirements (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Regulatory Capital Requirements [Abstract]
Component of statutory minimum capital requirement, percentage of the unpaid principal balance of outstanding Fannie Mae MBS held by third parties	0.45%
Component of critical capital requirement, percentage of the unpaid principal balance of outstanding Fannie Mae MBS held by third parties	0.25%
Number of days of that liabilities exceed assets requiring FHFA to place us into receivership	60 days
Net worth	$ 4,059	$ 4,000	$ 3,720	$ 9,591	$ 7,224
Core capital	(114,526)		(115,202)
Statutory minimum capital requirement	25,144		27,044
Deficit of core capital over statutory minimum capital requirement	$ (139,670)		$ (142,246)
Component of statutory minimum capital requirement, percentage of on-balance sheet assets, except those underlying Fannie Mae MBS held by third parties	2.50%
Component of statutory minimum capital requirement, maximum percentage of other off-balance sheet obligations	0.45%
Component of critical capital requirement, percentage of on-balance sheet assets, except those underlying Fannie Mae MBS held by third parties	1.25%
Component of critical capital requirement, percentage of other off-balance sheet obligations	0.25%

Concentrations of Credit Risk G

Concentrations of Credit Risk Geographic Concentration (Details) - Guaranty Book of Business [Member]	Dec. 31, 2015	Dec. 31, 2014
Single-Family [Member] | Conventional Mortgage [Member]
Concentration Risk [Line Items]
Percentage of book of business	100.00%	100.00%
Percentage of loans with detailed loan level information	99.00%	99.00%
Single-Family [Member] | Conventional Mortgage [Member] | Minimum [Member]
Concentration Risk [Line Items]
Percentage of loans with detailed loan level information	99.00%	99.00%
Single-Family [Member] | Conventional Mortgage [Member] | California
Concentration Risk [Line Items]
Percentage of book of business	20.00%	20.00%
Single-Family [Member] | Conventional Mortgage [Member] | New York
Concentration Risk [Line Items]
Percentage of book of business	5.00%	5.00%
Single-Family [Member] | Conventional Mortgage [Member] | Midwest [Member]
Concentration Risk [Line Items]
Percentage of book of business	15.00%	15.00%
Single-Family [Member] | Conventional Mortgage [Member] | Northeast [Member]
Concentration Risk [Line Items]
Percentage of book of business	19.00%	19.00%
Single-Family [Member] | Conventional Mortgage [Member] | Southeast [Member]
Concentration Risk [Line Items]
Percentage of book of business	22.00%	22.00%
Single-Family [Member] | Conventional Mortgage [Member] | Southwest [Member]
Concentration Risk [Line Items]
Percentage of book of business	16.00%	16.00%
Single-Family [Member] | Conventional Mortgage [Member] | West [Member]
Concentration Risk [Line Items]
Percentage of book of business	28.00%	28.00%
Multifamily [Member]
Concentration Risk [Line Items]
Percentage of book of business	100.00%	100.00%
Percentage of loans with detailed loan level information	99.00%	99.00%
Multifamily [Member] | California
Concentration Risk [Line Items]
Percentage of book of business	23.00%	23.00%
Multifamily [Member] | Texas
Concentration Risk [Line Items]
Percentage of book of business	11.00%	11.00%
Multifamily [Member] | New York
Concentration Risk [Line Items]
Percentage of book of business	10.00%	11.00%
Multifamily [Member] | Midwest [Member]
Concentration Risk [Line Items]
Percentage of book of business	9.00%	9.00%
Multifamily [Member] | Northeast [Member]
Concentration Risk [Line Items]
Percentage of book of business	17.00%	18.00%
Multifamily [Member] | Southeast [Member]
Concentration Risk [Line Items]
Percentage of book of business	23.00%	22.00%
Multifamily [Member] | Southwest [Member]
Concentration Risk [Line Items]
Percentage of book of business	21.00%	20.00%
Multifamily [Member] | West [Member]
Concentration Risk [Line Items]
Percentage of book of business	30.00%	31.00%

Concentrations of Credit Risk R

Concentrations of Credit Risk Risk Characteristics - SF (Details) - Single-Family [Member]	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Guaranty Book of Business [Member] | Conventional Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30 days delinquent (percentage of book of business)	1.27%	1.27%
60 days delinquent (percentage of book of business)	0.37%	0.38%
Seriously delinquent (percentage of book of business)	1.59%	1.99%
30 days delinquent (percentage of conventional loans)	1.46%	1.47%
60 days delinquent (percentage of conventional loans)	0.41%	0.43%
Seriously delinquent (percentage of conventional loans)	1.55%	1.89%
Percentage of book of business	100.00%	100.00%
Percentage of loans with detailed loan level information	99.00%	99.00%
Guaranty Book of Business [Member] | Conventional Mortgage [Member] | 2005 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	5.67%	6.18%
Percentage of book of business	2.00%	3.00%
Guaranty Book of Business [Member] | Conventional Mortgage [Member] | 2006 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	8.49%	9.61%
Percentage of book of business	3.00%	3.00%
Guaranty Book of Business [Member] | Conventional Mortgage [Member] | 2007 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	9.73%	10.79%
Percentage of book of business	3.00%	4.00%
Guaranty Book of Business [Member] | Conventional Mortgage [Member] | 2008 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	5.84%	6.27%
Percentage of book of business	2.00%	2.00%
Guaranty Book of Business [Member] | Conventional Mortgage [Member] | All other vintages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	0.77%	0.88%
Percentage of book of business	90.00%	88.00%
Guaranty Book of Business [Member] | Conventional Mortgage [Member] | Alt-A [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	6.53%	7.77%
Percentage of book of business	4.00%	4.00%
Guaranty Book of Business [Member] | Conventional Mortgage [Member] | California
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	0.58%	0.70%
Percentage of book of business	20.00%	20.00%
Guaranty Book of Business [Member] | Conventional Mortgage [Member] | Florida
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	2.86%	4.42%
Percentage of book of business	6.00%	6.00%
Guaranty Book of Business [Member] | Conventional Mortgage [Member] | New Jersey
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	4.87%	5.78%
Percentage of book of business	4.00%	4.00%
Guaranty Book of Business [Member] | Conventional Mortgage [Member] | New York
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	3.55%	4.17%
Percentage of book of business	5.00%	5.00%
Guaranty Book of Business [Member] | Conventional Mortgage [Member] | All other states [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	1.34%	1.57%
Percentage of book of business	65.00%	65.00%
Guaranty Book of Business [Member] | Conventional Mortgage [Member] | Estimated Mark-to-Market Loan-to-Value Ratio Greater Than 100% [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	10.76%	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
Minimum [Member] | Guaranty Book of Business [Member] | Conventional Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of loans with detailed loan level information	99.00%	99.00%

Concentrations of Credit Ris110

Concentrations of Credit Risk Risk Characteristics - MF (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current debt service coverage ratio (higher risk loans)	1	1
Multifamily [Member] | 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
Multifamily [Member] | Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Serious delinquency: days past due	89 days	89 days
Current debt service coverage ratio reporting lag	6 months	6 months
Multifamily [Member] | Guaranty Book of Business [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30 days delinquent (percentage of book of business)	0.03%	0.04%
Seriously delinquent (percentage of book of business)	0.07%	0.05%
Percentage of book of business	100.00%	100.00%
Percentage of loans with detailed loan level information	99.00%	99.00%
Multifamily [Member] | 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	1.51%	0.83%
Multifamily [Member] | 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	0.40%	0.31%
Multifamily [Member] | 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%

Concentrations of Credit Risk O

Concentrations of Credit Risk Other Concentrations (Details) $ in Millions	Dec. 31, 2015USD ($)servicerscounterpartiesinsurers	Dec. 31, 2014USD ($)servicerscounterpartiesinsurers	Jul. 21, 2014	Jul. 20, 2014
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	770	799
Unpaid principal balance of guaranteed non-agency securities in our portfolio	3,200	4,600
Maximum potential exposure under guarantees not recognized in our consolidated balance sheets	5,600	6,500
Unconsolidated Fannie Mae MBS [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Concentration Risk [Line Items]
Maximum coverage provided by our right to collateral backing underlying loans, available credit enhancements and recourse with third parties	$ 2,400	2,700
PMI [Member]
Concentration Risk [Line Items]
Percentage of mortgage guaranty insurance policy claims to be paid by insurer	70.00%
Mortgage insurance coverage risk in force percentage to be deferred	30.00%
Triad [Member]
Concentration Risk [Line Items]
Percentage of mortgage guaranty insurance policy claims to be paid by insurer	75.00%
Mortgage insurance coverage risk in force percentage to be deferred	25.00%
RMIC [Member]
Concentration Risk [Line Items]
Percentage of mortgage guaranty insurance policy claims to be paid by insurer	100.00%
Mortgage Sellers and Servicers [Member]
Concentration Risk [Line Items]
Receivable from claims on insured, defaulted loans excluding government insured loans	$ 241	$ 269
Ambac Assurance Corporation [Member]
Concentration Risk [Line Items]
Percentage of mortgage guaranty insurance policy claims to be paid by insurer			45.00%	25.00%
Ambac Assurance Corporation [Member] | Non-Government Guarantee [Member] | Insurance Service Provider Concentration Risk [Member]
Concentration Risk [Line Items]
Percentage of concentration risk	52.00%
Unpaid principal balance of guaranteed non-agency securities in our portfolio	$ 1,700
Mortgage revenue bonds [Member]
Concentration Risk [Line Items]
Percentage of unpaid principal balance of guaranteed non-agency securities in our portfolio	68.00%	70.00%
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Concentration Risk [Line Items]
Guaranteed securities issued by Freddie Mac, the federal government and its agencies	$ 16,700	$ 19,200
Single-Family [Member] | Guaranty Book of Business [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
Mortgage insurance coverage risk in force	$ 117,900	$ 109,600
Mortgage insurance coverage risk in force as percentage	4.00%	4.00%
Primary mortgage insurance coverage risk in force	$ 117,200	$ 108,700
Pool mortgage insurance coverage risk in force	$ 736	$ 852
Number of mortgage insurance companies provided majority of our mortgage insurance | insurers	4	4
Single-Family [Member] | Guaranty Book of Business [Member] | Insurance Service Provider Concentration Risk [Member]
Concentration Risk [Line Items]
Number of mortgage insurers publicly disclosed credit quality deterioration | insurers	3
Mortgage insurance coverage risk in force for insurers with credit quality deterioration	$ 10,100
Single-Family [Member] | Guaranty Book of Business [Member] | Mortgage Insurance Coverage [Member] | Insurance Service Provider Concentration Risk [Member]
Concentration Risk [Line Items]
Percentage of concentration risk	9.00%
Single-Family [Member] | Guaranty Book of Business [Member] | Group of Largest Mortgage Servicers including Affiliates [Member] | Unpaid Principal Balance [Member] | Credit Concentration Risk [Member]
Concentration Risk [Line Items]
Percentage of concentration risk	44.00%	46.00%
Single-Family [Member] | Guaranty Book of Business [Member] | Group of Top Mortgage Insurance Companies [Member] | Mortgage Insurance Coverage [Member] | Insurance Service Provider Concentration Risk [Member]
Concentration Risk [Line Items]
Percentage of concentration risk	79.00%	79.00%
Single-Family [Member] | Mortgage Credit Book of Business [Member] | Alt-A [Member] | Credit Concentration Risk [Member]
Concentration Risk [Line Items]
Unpaid principal balance of mortgage loans	$ 103,100	$ 117,600
Single-Family [Member] | Mortgage Credit Book of Business [Member] | Alt-A [Member] | Unpaid Principal Balance [Member] | Credit Concentration Risk [Member]
Concentration Risk [Line Items]
Percentage of book of business	4.00%	4.00%
Multifamily [Member]
Concentration Risk [Line Items]
Maximum potential loss recovery from lenders under risk sharing agreements	$ 46,200	$ 41,700
Multifamily [Member] | Lender Concentration Risk [Member]
Concentration Risk [Line Items]
Number of major lenders with risk sharing agreements | counterparties	4	4
Multifamily [Member] | Three Major Lenders [Member] | Lender Concentration Risk [Member]
Concentration Risk [Line Items]
Percentage of concentration risk	40.00%	39.00%
Multifamily [Member] | Guaranty Book of Business [Member]
Concentration Risk [Line Items]
Percentage of book of business	100.00%	100.00%
Number of mortgage servicers, including their affiliates, which serviced the majority of our guaranty book of business | servicers	10	10
Percentage of loans with detailed loan level information	99.00%	99.00%
Multifamily [Member] | Guaranty Book of Business [Member] | Group of Largest Mortgage Servicers including Affiliates [Member] | Unpaid Principal Balance [Member] | Credit Concentration Risk [Member]
Concentration Risk [Line Items]
Percentage of concentration risk	70.00%	67.00%
Conventional Mortgage [Member] | Single-Family [Member] | Guaranty Book of Business [Member]
Concentration Risk [Line Items]
Percentage of book of business	100.00%	100.00%
Percentage of loans with detailed loan level information	99.00%	99.00%
West [Member] | Multifamily [Member] | Guaranty Book of Business [Member]
Concentration Risk [Line Items]
Percentage of book of business	30.00%	31.00%
West [Member] | Conventional Mortgage [Member] | Single-Family [Member] | Guaranty Book of Business [Member]
Concentration Risk [Line Items]
Percentage of book of business	28.00%	28.00%
California | Multifamily [Member] | Guaranty Book of Business [Member]
Concentration Risk [Line Items]
Percentage of book of business	23.00%	23.00%
California | Conventional Mortgage [Member] | Single-Family [Member] | Guaranty Book of Business [Member]
Concentration Risk [Line Items]
Percentage of book of business	20.00%	20.00%
Minimum [Member] | Conventional Mortgage [Member] | Single-Family [Member] | Guaranty Book of Business [Member]
Concentration Risk [Line Items]
Percentage of loans with detailed loan level information	99.00%	99.00%

Netting Arrangements (Details)

Netting Arrangements (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Assets:
Derivative assets, gross amount	$ 4,890	$ 6,643
Derivative asset, gross amount offset	(4,024)	(5,186)
Derivative assets, net amount presented in the consolidated balance sheets	866	1,457
Derivative assets, under master netting arrangements, amounts not offset in the consolidated balance sheets, financial instruments	(119)	(116)
Derivative assets, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	(21)	(40)
Derivative assets, net amount	726	1,301
Securities purchased under agreements to resell, or similar arrangements, gross amount	37,950	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 consolidated balance sheets	37,950	47,550
Securities purchased under agreements to resell, under master netting arrangement, amounts not offset in the 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 consolidated balance sheets, collateral	(37,950)	(47,550)
Securities purchased under agreements to resell or similar arrangements, net amount	0	0
Total assets, gross amount	42,840	54,193
Total assets, gross amount offset	(4,024)	(5,186)
Total assets, net amount presented in the consolidated balance sheets	38,816	49,007
Total assets, under the master netting arrangements, not offset in the consolidated balance sheets, financial instruments	(119)	(116)
Total assets, under master netting arrangements, not offset in the consolidated balance sheets, collateral	(37,971)	(47,590)
Total assets, net amount	726	1,301
Liabilities:
Derivative liabilities, gross amount	(9,072)	(10,807)
Derivative liabilities, gross amount offset	8,650	10,194
Derivative liabilities, net amount presented in the consolidated balance sheets	(422)	(613)
Derivative liabilities, under master netting arrangements, amounts not offset in the consolidated balance sheets, financial instruments	119	116
Derivative liabilities, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	(1)	0
Derivative liabilities, net amount	(304)	(497)
Securities sold under agreements to repurchase or similar arrangements, gross amount	(62)	(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 consolidated balance sheets	62	50
Securities sold under agreements to repurchase or similar arrangements, under master netting arrangements, amounts not offset in the 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 consolidated balance sheets, collateral	62	50
Securities sold under agreements to repurchase or similar arrangements, net amount	0	0
Total liabilities, gross amount	(9,134)	(10,857)
Total liabilities, gross amount offset	8,650	10,194
Total liabilities, net amount presented in the consolidated balance sheets	(484)	(663)
Total liabilities, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, financial statements	119	116
Total liabilities, under master netting arrangements, amounts not offset in the condensed consolidated balance sheets, collateral	61	50
Total liabilities, net amount	(304)	(497)
Risk management derivatives [Member]
Assets:
Derivative asset, gross amount offset	(4,024)	(5,186)
Liabilities:
Derivative liabilities, gross amount offset	8,650	10,194
Risk management derivatives [Member] | OTC Risk Management Derivatives [Member]
Assets:
Derivative assets, gross amount	4,042	5,461
Derivative asset, gross amount offset	(4,021)	(5,428)
Derivative assets, net amount presented in the consolidated balance sheets	21	33
Derivative assets, under master netting arrangements, amounts not offset in the consolidated balance sheets, financial instruments	0	0
Derivative assets, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	(18)	(33)
Derivative assets, net amount	3	0
Liabilities:
Derivative liabilities, gross amount	(6,118)	(7,836)
Derivative liabilities, gross amount offset	5,861	7,567
Derivative liabilities, net amount presented in the consolidated balance sheets	(257)	(269)
Derivative liabilities, under master netting arrangements, amounts not offset in the consolidated balance sheets, financial instruments	0	0
Derivative liabilities, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	0	0
Derivative liabilities, net amount	(257)	(269)
Risk management derivatives [Member] | Cleared Risk Management Derivatives [Member]
Assets:
Derivative assets, gross amount	708	927
Derivative asset, gross amount offset	(3)	242
Derivative assets, net amount presented in the consolidated balance sheets	705	1,169
Derivative assets, under master netting arrangements, amounts not offset in the consolidated balance sheets, financial instruments	0	0
Derivative assets, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	0	0
Derivative assets, net amount	705	1,169
Liabilities:
Derivative liabilities, gross amount	(2,796)	(2,627)
Derivative liabilities, gross amount offset	2,789	2,627
Derivative liabilities, net amount presented in the consolidated balance sheets	(7)	0
Derivative liabilities, under master netting arrangements, amounts not offset in the consolidated balance sheets, financial instruments	0	0
Derivative liabilities, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	0	0
Derivative liabilities, net amount	(7)	0
Mortgage commitment derivatives [Member]
Assets:
Derivative assets, gross amount	140	255
Derivative asset, gross amount offset	0	0
Derivative assets, net amount presented in the consolidated balance sheets	140	255
Derivative assets, under master netting arrangements, amounts not offset in the consolidated balance sheets, financial instruments	(119)	(116)
Derivative assets, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	(3)	(7)
Derivative assets, net amount	18	132
Liabilities:
Derivative liabilities, gross amount	(158)	(344)
Derivative liabilities, gross amount offset	0	0
Derivative liabilities, net amount presented in the consolidated balance sheets	(158)	(344)
Derivative liabilities, under master netting arrangements, amounts not offset in the consolidated balance sheets, financial instruments	119	116
Derivative liabilities, under master netting arrangements, amounts not offset in the consolidated balance sheets, collateral	(1)	0
Derivative liabilities, net amount	$ (40)	$ (228)

Netting Arrangements Narratives

Netting Arrangements Narratives (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Derivative [Line Items]
Derivative assets not subject to an enforceable master netting arrangement	$ 28,000,000	$ 28,000,000
Derivative liabilities not subject to an enforceable master netting arrangement	2,000,000	1,000,000
Cash and cash equivalents [Member]
Derivative [Line Items]
Securities purchased under agreements to resell	10,600,000,000	16,600,000,000
Securities purchased under agreements to resell [Member]
Derivative [Line Items]
Fair value of non-cash collateral accepted	38,000,000,000	47,600,000,000
Fair value of non-cash collateral accepted that could be sold or repledged	36,200,000,000	41,900,000,000
Fair value of securities 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 for securities sold under agreements to repurchase	62,000,000	50,000,000
Cleared Risk Management Derivatives [Member]
Derivative [Line Items]
Fair value of non-cash collateral pledged for cleared risk management derivatives	135,000,000
OTC Risk Management Derivatives [Member]
Derivative [Line Items]
Fair value of non-cash collateral accepted	$ 37,000,000	$ 51,000,000

Fair Value Levels Hierarchy (De

Fair Value Levels Hierarchy (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Assets [Abstract]
Mortgage loans held for investment, at fair value	$ 14,075	$ 15,629
Other assets [Abstract]
Derivative asset, gross amount offset	(4,024)	(5,186)
Other liabilities [Abstract]
Derivative liabilities, gross amount offset	(8,650)	(10,194)
Mortgage commitment derivatives [Member]
Other assets [Abstract]
Derivative asset, 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	11,133	6,403
Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	23,609	19,483
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets [Abstract]
Trading securities	29,485	19,466
Available-for-sale securities	0	0
Mortgage loans held for investment, at fair value	0	0
Total assets at fair value	64,438	57,431
Other assets [Abstract]
Derivatives assets at fair value	0	0
Liabilities [Abstract]
Total liabilities at fair value	0	0
Other liabilities [Abstract]
Derivatives 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	9,025	9,008
Available-for-sale securities	11,799	15,574
Mortgage loans held for investment, at fair value	2,702,526	2,687,759
Total assets at fair value	2,770,088	2,771,628
Other assets [Abstract]
Derivatives assets at fair value	4,729	6,489
Liabilities [Abstract]
Total liabilities at fair value	3,224,091	3,299,289
Other liabilities [Abstract]
Derivatives liabilities at fair value	9,042	10,671
Significant Other Observable Inputs (Level 2) [Member] | Fannie Mae [Member]
Assets [Abstract]
Mortgage loans held for investment, at fair value	26,544	29,896
Liabilities [Abstract]
Long-term debt, fair value	324,248	367,703
Significant Other Observable Inputs (Level 2) [Member] | Consolidated Trusts [Member]
Assets [Abstract]
Mortgage loans held for investment, at fair value	2,675,982	2,657,863
Liabilities [Abstract]
Long-term debt, fair value	2,819,733	2,815,843
Significant Unobservable Inputs (Level 3) [Member]
Assets [Abstract]
Trading securities	1,398	3,030
Available-for-sale securities	8,431	15,080
Mortgage loans held for investment, at fair value	351,355	400,327
Total assets at fair value	367,852	419,874
Other assets [Abstract]
Derivatives assets at fair value	189	182
Liabilities [Abstract]
Total liabilities at fair value	30,061	23,592
Other liabilities [Abstract]
Derivatives liabilities at fair value	32	137
Significant Unobservable Inputs (Level 3) [Member] | Fannie Mae [Member]
Assets [Abstract]
Mortgage loans held for investment, at fair value	193,670	217,064
Liabilities [Abstract]
Long-term debt, fair value	898	982
Significant Unobservable Inputs (Level 3) [Member] | Consolidated Trusts [Member]
Assets [Abstract]
Mortgage loans held for investment, at fair value	157,685	183,263
Liabilities [Abstract]
Long-term debt, fair value	27,175	19,334
Estimate of Fair Value Measurement [Member]
Assets [Abstract]
Trading securities	39,908	31,504
Available-for-sale securities	20,230	30,654
Mortgage loans held for investment, at fair value	3,053,881	3,088,086
Total assets at fair value	3,198,354	3,243,747
Other assets [Abstract]
Derivatives assets at fair value	894	1,485
Liabilities [Abstract]
Total liabilities at fair value	3,245,502	3,312,687
Other liabilities [Abstract]
Derivatives liabilities at fair value	424	614
Estimate of Fair Value Measurement [Member] | Fannie Mae [Member]
Assets [Abstract]
Mortgage loans held for investment, at fair value	220,214	246,960
Liabilities [Abstract]
Long-term debt, fair value	325,146	368,685
Estimate of Fair Value Measurement [Member] | Consolidated Trusts [Member]
Assets [Abstract]
Mortgage loans held for investment, at fair value	2,833,667	2,841,126
Liabilities [Abstract]
Long-term debt, fair value	2,846,908	2,835,177
Recurring Fair Value Measurements [Member]
Other assets [Abstract]
Derivative asset, gross amount offset	(4,024)	(5,186)
Other liabilities [Abstract]
Derivative liabilities, gross amount offset	(8,650)	(10,194)
Recurring Fair Value Measurements [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets [Abstract]
Trading securities	29,485	19,466
Available-for-sale securities	0	0
Total assets at fair value	29,485	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]
Derivatives 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]
Derivatives 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]
Derivatives 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]
Derivatives 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]
Derivatives 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]
Assets [Abstract]
Mortgage loans held for investment, at fair value	0	0
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	29,485	19,466
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets [Abstract]
Trading securities	9,025	9,008
Available-for-sale securities	11,799	15,574
Total assets at fair value	38,151	44,867
Other assets [Abstract]
Derivatives assets at fair value	4,729	6,489
Liabilities [Abstract]
Long-term debt, fair value	33,877	24,996
Total liabilities at fair value	42,919	35,667
Other liabilities [Abstract]
Derivatives liabilities at fair value	9,042	10,671
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Swaps [Member]
Other assets [Abstract]
Derivatives assets at fair value	4,541	6,085
Other liabilities [Abstract]
Derivatives liabilities at fair value	8,697	9,339
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Swaptions [Member]
Other assets [Abstract]
Derivatives assets at fair value	53	153
Other liabilities [Abstract]
Derivatives liabilities at fair value	197	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]
Derivatives 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	135	251
Other liabilities [Abstract]
Derivatives liabilities at fair value	148	341
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	10,764	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	10,764	6,040
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Consolidated Trusts [Member]
Assets [Abstract]
Mortgage loans held for investment, at fair value	12,598	13,796
Liabilities [Abstract]
Long-term debt, fair value	23,113	18,956
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fannie Mae [Member]
Assets [Abstract]
Trading securities	4,813	4,635
Available-for-sale securities	4,221	5,639
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Freddie Mac [Member]
Assets [Abstract]
Trading securities	1,314	1,369
Available-for-sale securities	4,295	5,522
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Ginnie Mae [Member]
Assets [Abstract]
Trading securities	426	166
Available-for-sale securities	391	476
Recurring Fair Value Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member] | Alt-A private-label securities [Member]
Assets [Abstract]
Trading securities	131	323
Available-for-sale securities	1,637	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	2,341	2,515
Available-for-sale securities	1,255	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	0	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	1,398	3,030
Available-for-sale securities	8,431	15,080
Mortgage loans held for investment, at fair value	1,477	1,833
Total assets at fair value	11,495	20,125
Other assets [Abstract]
Derivatives assets at fair value	189	182
Liabilities [Abstract]
Long-term debt, fair value	865	890
Total liabilities at fair value	897	1,027
Other liabilities [Abstract]
Derivatives liabilities at fair value	32	137
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Swaps [Member]
Other assets [Abstract]
Derivatives assets at fair value	156	150
Other liabilities [Abstract]
Derivatives liabilities at fair value	20	133
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Swaptions [Member]
Other assets [Abstract]
Derivatives assets at fair value	0	0
Other liabilities [Abstract]
Derivatives 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	28	28
Other liabilities [Abstract]
Derivatives liabilities at fair value	2	1
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Mortgage commitment derivatives [Member]
Other assets [Abstract]
Derivatives assets at fair value	5	4
Other liabilities [Abstract]
Derivatives liabilities at fair value	10	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]
Assets [Abstract]
Mortgage loans held for investment, at fair value	1,477	1,833
Liabilities [Abstract]
Long-term debt, fair value	496	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	305	597
Available-for-sale securities	1,041	3,140
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Subprime private-label securities [Member]
Assets [Abstract]
Trading securities	644	1,307
Available-for-sale securities	3,281	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	449	722
Available-for-sale securities	2,701	4,023
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other [Member]
Assets [Abstract]
Trading securities		99
Available-for-sale securities	1,404	2,671
Recurring Fair Value Measurements [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. Treasury Securities [Member]
Assets [Abstract]
Trading securities	0	0
Recurring Fair Value Measurements [Member] | Estimate of Fair Value Measurement [Member]
Assets [Abstract]
Trading securities	39,908	31,504
Available-for-sale securities	20,230	30,654
Mortgage loans held for investment, at fair value	14,075	15,629
Total assets at fair value	75,107	79,272
Other assets [Abstract]
Derivatives assets at fair value	894	1,485
Liabilities [Abstract]
Long-term debt, fair value	34,742	25,886
Total liabilities at fair value	35,166	26,500
Other liabilities [Abstract]
Derivatives liabilities at fair value	424	614
Recurring Fair Value Measurements [Member] | Estimate of Fair Value Measurement [Member] | Swaps [Member]
Other assets [Abstract]
Derivatives assets at fair value	4,697	6,235
Other liabilities [Abstract]
Derivatives liabilities at fair value	8,717	9,472
Recurring Fair Value Measurements [Member] | Estimate of Fair Value Measurement [Member] | Swaptions [Member]
Other assets [Abstract]
Derivatives assets at fair value	53	153
Other liabilities [Abstract]
Derivatives liabilities at fair value	197	991
Recurring Fair Value Measurements [Member] | Estimate of Fair Value Measurement [Member] | Other [Member]
Other assets [Abstract]
Derivatives assets at fair value	28	28
Other liabilities [Abstract]
Derivatives liabilities at fair value	2	1
Recurring Fair Value Measurements [Member] | Estimate of Fair Value Measurement [Member] | Netting Adjustment [Member]
Other assets [Abstract]
Derivative asset, gross amount offset	(4,024)	(5,186)
Other liabilities [Abstract]
Derivative liabilities, gross amount offset	(8,650)	(10,194)
Recurring Fair Value Measurements [Member] | Estimate of Fair Value Measurement [Member] | Mortgage commitment derivatives [Member]
Other assets [Abstract]
Derivatives assets at fair value	140	255
Other liabilities [Abstract]
Derivatives liabilities at fair value	158	344
Recurring Fair Value Measurements [Member] | Estimate of Fair Value Measurement [Member] | Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	11,133	6,403
Recurring Fair Value Measurements [Member] | Estimate of Fair Value Measurement [Member] | Fannie Mae [Member] | Senior Floating [Member]
Liabilities [Abstract]
Long-term debt, fair value	11,133	6,403
Recurring Fair Value Measurements [Member] | Estimate of Fair Value Measurement [Member] | Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	23,609	19,483
Recurring Fair Value Measurements [Member] | Estimate of Fair Value Measurement [Member] | Fannie Mae [Member]
Assets [Abstract]
Trading securities	4,813	4,940
Available-for-sale securities	4,221	5,639
Recurring Fair Value Measurements [Member] | Estimate of Fair Value Measurement [Member] | Freddie Mac [Member]
Assets [Abstract]
Trading securities	1,314	1,369
Available-for-sale securities	4,299	5,528
Recurring Fair Value Measurements [Member] | Estimate of Fair Value Measurement [Member] | Ginnie Mae [Member]
Assets [Abstract]
Trading securities	426	166
Available-for-sale securities	391	476
Recurring Fair Value Measurements [Member] | Estimate of Fair Value Measurement [Member] | Alt-A private-label securities [Member]
Assets [Abstract]
Trading securities	436	920
Available-for-sale securities	2,678	5,678
Recurring Fair Value Measurements [Member] | Estimate of Fair Value Measurement [Member] | Subprime private-label securities [Member]
Assets [Abstract]
Trading securities	644	1,307
Available-for-sale securities	3,281	5,240
Recurring Fair Value Measurements [Member] | Estimate of Fair Value Measurement [Member] | CMBS [Member]
Assets [Abstract]
Trading securities	2,341	2,515
Available-for-sale securities	1,255	1,397
Recurring Fair Value Measurements [Member] | Estimate of Fair Value Measurement [Member] | Mortgage revenue bonds [Member]
Assets [Abstract]
Trading securities	449	722
Available-for-sale securities	2,701	4,023
Recurring Fair Value Measurements [Member] | Estimate of Fair Value Measurement [Member] | Other [Member]
Assets [Abstract]
Trading securities		99
Available-for-sale securities	1,404	2,673
Recurring Fair Value Measurements [Member] | Estimate of Fair Value Measurement [Member] | U.S. Treasury Securities [Member]
Assets [Abstract]
Trading securities	$ 29,485	$ 19,466

Fair Value Level 3 Rollforward

Fair Value Level 3 Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Trading securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 3,030	$ 2,774	$ 2,286
Total gains or (losses) (realized/unrealized) Included in Net Income	8	512	469
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	0	0	0
Purchases	0	6	0
Sales	(1,200)	(299)	(50)
Issues	0	0	0
Settlements	(148)	(277)	(304)
Transfers out of Level 3	(322)	(267)	(438)
Transfers into Level 3	30	581	811
Ending Balance	1,398	3,030	2,774
Net Unrealized Gains (Losses) included in net income related to assets still held	(8)	486	430
Trading securities [Member] | Fannie Mae [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	305	42	68
Total gains or (losses) (realized/unrealized) Included in Net Income	(27)	(27)	(9)
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	0	0	0
Purchases	0	6	0
Sales	(2)	0	0
Issues	0	0	0
Settlements	0	(2)	(17)
Transfers out of Level 3	(278)	(39)	0
Transfers into Level 3	2	325	0
Ending Balance	0	305	42
Net Unrealized Gains (Losses) included in net income related to assets still held	0	(18)	(9)
Trading securities [Member] | Freddie Mac [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	0	2	2
Total gains or (losses) (realized/unrealized) Included in Net Income		0	0
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income		0	0
Purchases		0	0
Sales		0	0
Issues		0	0
Settlements		0	0
Transfers out of Level 3		(2)	0
Transfers into Level 3		0	0
Ending Balance		0	2
Net Unrealized Gains (Losses) included in net income related to assets still held		0	0
Trading securities [Member] | Ginnie Mae [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance		0	1
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			(1)
Transfers out of Level 3			(3)
Transfers into Level 3			3
Ending Balance			0
Net Unrealized Gains (Losses) included in net income related to assets still held			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	597	618	104
Total gains or (losses) (realized/unrealized) Included in Net Income	36	88	256
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	0	0	0
Purchases	0	0	0
Sales	(267)	(58)	0
Issues	0	0	0
Settlements	(45)	(81)	(115)
Transfers out of Level 3	(44)	(226)	(435)
Transfers into Level 3	28	256	808
Ending Balance	305	597	618
Net Unrealized Gains (Losses) included in net income related to assets still held	15	97	223
Trading securities [Member] | Subprime private-label securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,307	1,448	1,319
Total gains or (losses) (realized/unrealized) Included in Net Income	36	270	328
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	0	0	0
Purchases	0	0	0
Sales	(611)	(241)	(50)
Issues	0	0	0
Settlements	(88)	(170)	(149)
Transfers out of Level 3	0	0	0
Transfers into Level 3	0	0	0
Ending Balance	644	1,307	1,448
Net Unrealized Gains (Losses) included in net income related to assets still held	10	234	322
Trading securities [Member] | Mortgage revenue bonds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	722	565	675
Total gains or (losses) (realized/unrealized) Included in Net Income	(41)	168	(101)
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	0	0	0
Purchases	0	0	0
Sales	(220)	0	0
Issues	0	0	0
Settlements	(12)	(11)	(9)
Transfers out of Level 3	0	0	0
Transfers into Level 3	0	0	0
Ending Balance	449	722	565
Net Unrealized Gains (Losses) included in net income related to assets still held	(33)	160	(101)
Trading securities [Member] | Other [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	99	99	117
Total gains or (losses) (realized/unrealized) Included in Net Income	4	13	(5)
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	0	0	0
Purchases	0	0	0
Sales	(100)	0	0
Issues	0	0	0
Settlements	(3)	(13)	(13)
Transfers out of Level 3	0	0	0
Transfers into Level 3	0	0	0
Ending Balance	0	99	99
Net Unrealized Gains (Losses) included in net income related to assets still held	0	13	(5)
Available-for-sale securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	15,080	19,012	25,034
Total gains or (losses) (realized/unrealized) Included in Net Income	839	606	302
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	(661)	932	1,665
Purchases	421	0	359
Sales	(4,926)	(2,193)	(4,016)
Issues	0	0	0
Settlements	(2,132)	(3,337)	(4,642)
Transfers out of Level 3	(540)	(1,748)	(3,373)
Transfers into Level 3	350	1,808	3,683
Ending Balance	8,431	15,080	19,012
Net Unrealized Gains (Losses) included in net income related to assets still held	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	0	7	29
Total gains or (losses) (realized/unrealized) Included in Net Income	0	0	0
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	0	0	(1)
Purchases	421	0	0
Sales	(425)	0	0
Issues	0	0	0
Settlements	(8)	(1)	(7)
Transfers out of Level 3	0	(8)	(14)
Transfers into Level 3	12	2	0
Ending Balance	0	0	7
Net Unrealized Gains (Losses) included in net income related to assets still held	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	6	8	10
Total gains or (losses) (realized/unrealized) Included in Net Income	0	0	0
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	0	0	(1)
Purchases	0	0	0
Sales	0	0	0
Issues	0	0	0
Settlements	(1)	(1)	(2)
Transfers out of Level 3	(2)	(2)	(1)
Transfers into Level 3	1	1	2
Ending Balance	4	6	8
Net Unrealized Gains (Losses) included in net income related to assets still held	0	0	0
Available-for-sale securities [Member] | Ginnie Mae [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance		0	0
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			(1)
Transfers into Level 3			1
Ending Balance			0
Net Unrealized Gains (Losses) included in net income related to assets still held			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	3,140	3,791	6,564
Total gains or (losses) (realized/unrealized) Included in Net Income	215	172	144
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	(173)	(26)	464
Purchases	0	0	0
Sales	(1,504)	(393)	(2,664)
Issues	0	0	0
Settlements	(436)	(471)	(1,040)
Transfers out of Level 3	(538)	(1,738)	(3,357)
Transfers into Level 3	337	1,805	3,680
Ending Balance	1,041	3,140	3,791
Net Unrealized Gains (Losses) included in net income related to assets still held	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	5,240	7,068	7,447
Total gains or (losses) (realized/unrealized) Included in Net Income	599	447	120
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	(382)	301	1,527
Purchases	0	0	359
Sales	(1,575)	(1,730)	(1,317)
Issues	0	0	0
Settlements	(601)	(846)	(1,068)
Transfers out of Level 3	0	0	0
Transfers into Level 3	0	0	0
Ending Balance	3,281	5,240	7,068
Net Unrealized Gains (Losses) included in net income related to assets still held	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	4,023	5,253	7,837
Total gains or (losses) (realized/unrealized) Included in Net Income	51	(32)	25
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	(104)	554	(449)
Purchases	0	0	0
Sales	(410)	(70)	(35)
Issues	0	0	0
Settlements	(859)	(1,682)	(2,125)
Transfers out of Level 3	0	0	0
Transfers into Level 3	0	0	0
Ending Balance	2,701	4,023	5,253
Net Unrealized Gains (Losses) included in net income related to assets still held	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	2,671	2,885	3,147
Total gains or (losses) (realized/unrealized) Included in Net Income	(26)	19	13
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	(2)	103	125
Purchases	0	0	0
Sales	(1,012)	0	0
Issues	0	0	0
Settlements	(227)	(336)	(400)
Transfers out of Level 3	0	0	0
Transfers into Level 3	0	0	0
Ending Balance	1,404	2,671	2,885
Net Unrealized Gains (Losses) included in net income related to assets still held	0	0	0
Mortgage loans [Member] | Consolidated Trusts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,833	2,704	2,634
Total gains or (losses) (realized/unrealized) Included in Net Income	57	260	282
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	0	0	0
Purchases	5	36	346
Sales	0	0	(393)
Issues	0	0	0
Settlements	(350)	(344)	(459)
Transfers out of Level 3	(377)	(1,113)	(352)
Transfers into Level 3	309	290	646
Ending Balance	1,477	1,833	2,704
Net Unrealized Gains (Losses) included in net income related to assets still held	(20)	53	50
Net derivatives [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	45	(40)	14
Total gains or (losses) (realized/unrealized) Included in Net Income	(55)	103	(165)
Total gains or (losses) (realized/unrealized) Included in Other Comprehensive Income	0	0	0
Purchases	0	0	0
Sales	0	0	0
Issues	(4)	0	0
Settlements	169	(21)	97
Transfers out of Level 3	(7)	(2)	16
Transfers into Level 3	9	5	(2)
Ending Balance	157	45	(40)
Net Unrealized Gains (Losses) included in net income related to assets still held	(2)	77	(51)
Long-term Debt [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(890)	(1,473)	(1,528)
Total gains (losses) (realized/unrealized) Included in Net Income	(15)	(195)	(174)
Total gains (losses) Included in Other Comprehensive Income	0	0	0
Purchases	0	0	0
Sales	0	0	0
Issues	(66)	(751)	(695)
Settlements	57	81	580
Transfers out of Level 3	228	1,576	434
Transfers Into Level 3	(179)	(128)	(90)
Ending Balance	(865)	(890)	(1,473)
Net unrealized Gains (Losses) included in net income related to Liabilities still held	11	(146)	(4)
Long-term Debt [Member] | Consolidated Trusts [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(527)	(518)	(1,128)
Total gains (losses) (realized/unrealized) Included in Net Income	(9)	(53)	(250)
Total gains (losses) Included in Other Comprehensive Income	0	0	0
Purchases	0	0	0
Sales	0	0	0
Issues	(66)	(1)	(21)
Settlements	57	62	537
Transfers out of Level 3	228	111	434
Transfers Into Level 3	(179)	(128)	(90)
Ending Balance	(496)	(527)	(518)
Net unrealized Gains (Losses) included in net income related to Liabilities still held	17	(49)	(80)
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	(363)	(955)	(400)
Total gains (losses) (realized/unrealized) Included in Net Income	(6)	(142)	76
Total gains (losses) Included in Other Comprehensive Income	0	0	0
Purchases	0	0	0
Sales	0	0	0
Issues	0	(750)	(674)
Settlements	0	19	43
Transfers out of Level 3	0	1,465	0
Transfers Into Level 3	0	0	0
Ending Balance	(369)	(363)	(955)
Net unrealized Gains (Losses) included in net income related to Liabilities still held	$ (6)	$ (97)	$ 76

Fair Value Level 3 Valuation In

Fair Value Level 3 Valuation Inputs - Recurring (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	$ 14,075	$ 15,629
Derivatives	866	1,457
Fannie Mae [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term debt	(11,133)	(6,403)
Consolidated Trusts [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term debt	(23,609)	(19,483)
Significant Unobservable Inputs (Level 3) [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	1,398	3,030
Available-for-sale securities	8,431	15,080
Mortgage loans held for investment, at fair value	351,355	400,327
Significant Unobservable Inputs (Level 3) [Member] | Fannie Mae [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	193,670	217,064
Long-term debt	(898)	(982)
Significant Unobservable Inputs (Level 3) [Member] | Consolidated Trusts [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	157,685	183,263
Long-term debt	(27,175)	(19,334)
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	1,398	3,030
Available-for-sale securities	8,431	15,080
Mortgage loans held for investment, at fair value	1,477	1,833
Derivatives	157	45
Long-term debt	(865)	(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	305	597
Available-for-sale securities	1,041	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	644	1,307
Available-for-sale securities	3,281	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	449	722
Available-for-sale securities	2,701	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	1,404	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%
Spread (bps)		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%
Spread (bps)		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%
Spread (bps)		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	305	$ 66
Available-for-sale securities	$ 671	$ 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 (%)	1.30%	5.40%
Prepayment Speed (%)	2.20%	7.00%
Severity (%)	20.50%	48.80%
Spread (bps)	2.19%	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 (%)	4.90%	5.40%
Prepayment Speed (%)	4.50%	7.00%
Severity (%)	95.00%	48.80%
Spread (bps)	2.633%	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 (%)	3.60%	5.40%
Prepayment Speed (%)	3.70%	7.00%
Severity (%)	69.30%	48.80%
Spread (bps)	2.531%	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 (%)	0.50%	0.40%
Prepayment Speed (%)	1.70%	0.10%
Severity (%)	1.40%	0.20%
Spread (bps)	2.256%	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 (%)	40.70%	31.20%
Prepayment Speed (%)	72.60%	48.90%
Severity (%)	95.00%	95.00%
Spread (bps)	2.804%	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 (%)	3.40%	5.10%
Prepayment Speed (%)	13.50%	11.00%
Severity (%)	58.50%	59.60%
Spread (bps)	2.60%	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	$ 526	$ 422
Available-for-sale securities	$ 1,848	$ 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 (%)	4.20%	3.50%
Prepayment Speed (%)	0.40%	1.40%
Severity (%)	55.90%	72.10%
Spread (bps)	2.85%	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 (%)	8.40%	11.80%
Prepayment Speed (%)	5.30%	5.20%
Severity (%)	95.00%	95.00%
Spread (bps)	2.85%	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 (%)	5.90%	7.20%
Prepayment Speed (%)	3.30%	2.80%
Severity (%)	73.70%	85.90%
Spread (bps)	2.85%	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 (%)	0.50%	0.10%
Severity (%)	20.00%	1.50%
Spread (bps)	2.55%	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 (%)	11.30%	37.40%
Prepayment Speed (%)	11.20%	17.70%
Severity (%)	95.00%	95.00%
Spread (bps)	2.85%	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 (%)	5.90%	6.30%
Prepayment Speed (%)	3.80%	2.60%
Severity (%)	79.00%	84.40%
Spread (bps)	2.833%	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	$ 683	$ 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 (%)	0.50%	0.10%
Prepayment Speed (%)	2.50%	3.00%
Severity (%)	6.60%	0.40%
Spread (bps)	2.00%	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 (%)	15.50%	30.40%
Severity (%)	95.00%	95.00%
Spread (bps)	4.544%	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 (%)	4.70%	4.80%
Severity (%)	65.70%	62.40%
Spread (bps)	3.156%	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	$ 201	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	73	549
Available-for-sale securities	945	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]
Available-for-sale securities	$ 169	$ 403
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 (%)	4.00%	0.50%
Severity (%)	50.00%	35.10%
Spread (bps)	2.60%	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 (%)	5.00%	11.50%
Prepayment Speed (%)	7.50%	8.40%
Severity (%)	64.00%	92.40%
Spread (bps)	3.694%	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 (%)	4.80%	7.00%
Prepayment Speed (%)	6.40%	3.40%
Severity (%)	59.20%	54.20%
Spread (bps)	2.965%	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		$ 290
Available-for-sale securities		$ 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 (%)		4.30%
Prepayment Speed (%)		2.30%
Severity (%)		62.20%
Spread (bps)		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 (%)		6.20%
Prepayment Speed (%)		4.20%
Severity (%)		95.00%
Spread (bps)		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 (%)		5.20%
Prepayment Speed (%)		3.30%
Severity (%)		73.80%
Spread (bps)		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 (%)		3.00%
Prepayment Speed (%)		1.10%
Severity (%)		28.90%
Spread (bps)		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 (%)		12.30%
Prepayment Speed (%)		9.00%
Severity (%)		91.80%
Spread (bps)		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 (%)		7.00%
Prepayment Speed (%)		4.10%
Severity (%)		81.20%
Spread (bps)		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	$ 437	$ 540
Available-for-sale securities	$ 1,462	$ 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]
Spread (bps)	0.015%	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]
Spread (bps)	3.762%	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]
Spread (bps)	2.989%	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]
Spread (bps)	(0.158%)	(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]
Spread (bps)	3.791%	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]
Spread (bps)	2.838%	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	$ 520
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 (%)	95.00%
Spread (bps)	2.60%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Discounted Cash Flow with Inputs [Member] | Other [Member] | Available-for-sale securities [Member] | Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Default Rate (%)	1.80%
Prepayment Speed (%)	0.50%
Severity (%)	95.00%
Spread (bps)	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 (%)	0.00%
Prepayment Speed (%)	0.00%
Severity (%)	95.00%
Spread (bps)	3.236%
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%
Spread (bps)		256.50%
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%
Spread (bps)		350.80%
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%
Spread (bps)		293.40%
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%
Spread (bps)		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%
Spread (bps)		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%
Spread (bps)		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%
Spread (bps)		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%
Spread (bps)		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%
Spread (bps)		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	$ 343	$ 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 (%)	2.50%	2.10%
Prepayment Speed (%)	1.90%	1.50%
Severity (%)	67.60%	65.40%
Spread (bps)	2.85%	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 (%)	7.50%	8.30%
Prepayment Speed (%)	5.70%	3.30%
Severity (%)	85.70%	95.00%
Spread (bps)	3.40%	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 (%)	4.80%	5.50%
Prepayment Speed (%)	3.30%	2.10%
Severity (%)	72.70%	78.50%
Spread (bps)	2.996%	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	$ 991	$ 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]
Spread (bps)	(0.331%)	(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]
Spread (bps)	3.868%	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]
Spread (bps)	0.379%	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%
Spread (bps)		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%
Spread (bps)		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%
Spread (bps)		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	$ 17	(107)
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]
Spread (bps)		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]
Spread (bps)		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]
Spread (bps)		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]
Spread (bps)		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]
Spread (bps)		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]
Spread (bps)		2.659%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Dealer Mark without Input [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Derivatives	136	$ 150
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Dealer Mark without Input [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] | Other Valuation Technique [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Derivatives	4	2
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Other Valuation Technique [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 [Member] | Alt-A private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities		90
Available-for-sale securities		44
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Other Valuation Technique [Member] | Subprime private-label securities [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	45	46
Available-for-sale securities	145	63
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Other Valuation Technique [Member] | Mortgage revenue bonds [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	12	21
Available-for-sale securities	248	10
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Other Valuation Technique [Member] | Other [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	201	399
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-Family [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	1,321	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]
Mortgage loans held for investment, at fair value	$ 234
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 (%)	0.50%
Prepayment Speed (%)	2.50%
Severity (%)	20.00%
Spread (bps)	2.55%
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 (%)	5.00%
Prepayment Speed (%)	26.00%
Severity (%)	89.10%
Spread (bps)	2.776%
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 (%)	3.70%
Prepayment Speed (%)	6.40%
Severity (%)	69.00%
Spread (bps)	2.646%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-Family [Member] | Consensus Without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	$ 274	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]
Mortgage loans held for investment, at fair value		$ 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%
Spread (bps)		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%
Spread (bps)		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%
Spread (bps)		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]
Mortgage loans held for investment, at fair value	$ 127	$ 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 (%)	99.20%	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 (%)	34.80%	14.90%
Prepayment Speed (%)	10.40%	16.30%
Severity (%)	39.90%	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]
Mortgage loans held for investment, at fair value	$ 632
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Single-Family [Member] | Other Valuation Technique [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	54	$ 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]
Mortgage loans held for investment, at fair value	$ 156	$ 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]
Spread (bps)	0.70%	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]
Spread (bps)	3.272%	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]
Spread (bps)	1.588%	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	$ (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	(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	(369)	(363)
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	1,477	1,833
Long-term debt	(496)	(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	$ (181)
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 (%)	0.50%
Prepayment Speed (%)	2.50%
Severity (%)	20.00%
Spread (bps)	2.55%
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 (%)	3.80%
Prepayment Speed (%)	26.00%
Severity (%)	80.60%
Spread (bps)	2.70%
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 (%)	3.40%
Prepayment Speed (%)	5.60%
Severity (%)	67.80%
Spread (bps)	2.658%
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	$ (149)	(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		$ (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%
Spread (bps)		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%
Spread (bps)		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%
Spread (bps)		2.494%
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member] | Consolidated Trusts [Member] | Other Valuation Technique [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Long-term debt	$ (166)	$ (103)

Fair Value Level 3 Valuation -

Fair Value Level 3 Valuation - Nonrecurring (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	$ 14,075	$ 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	157	169
Mortgage loans held for investment, at fair value	2,702,526	2,687,759
Total assets at fair value	2,770,088	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	5,541	169
Mortgage loans held for investment, at fair value	351,355	400,327
Total assets at fair value	367,852	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	17	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	3,991	110
Total assets at fair value	13,934	22,416
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	3,651	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	336	0
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other Valuation Technique [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for sale, at lower of cost or fair value	4	0
Other assets	$ 30	$ 45
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Accepted Offers [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Number of properties measured	18.00%	19.00%
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Proprietary Home Price Model and Appraisals [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Number of properties measured	77.00%	77.00%
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	$ 6,379	$ 16,714
Acquired property, net	3,211	4,782
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Single-Family [Member] | Other Valuation Technique [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	0	60
Acquired property, net	134	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	6,379	16,654
Acquired property, net	986	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	541	864
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	1,117	1,509
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	433	1,173
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	323	625
Acquired property, net	0	140
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Multifamily [Member] | Other Valuation Technique [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	5	0
Acquired property, net	0	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	82	45
Acquired property, net	0	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	$ 236	$ 580

Fair Value of Financial Instrum

Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	$ 14,075	$ 15,629
Netting adjustment	(4,024)	(5,186)
Financial liabilities [Abstract]
Netting adjustment	(8,650)	(10,194)
HARP Loans [Member]
Financial liabilities [Abstract]
Loans Receivable Refinanced under Home Affordable Refinance Program, Fair Value Disclosure	282,000	314,000
Fair Value Estimation Process [Member] | HARP Loans [Member]
Financial liabilities [Abstract]
Change In Estimated Fair Value Resulting From Change In Principal Market	1,100	3,300
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets [Abstract]
Cash and cash equivalents and restricted cash	34,953	37,965
Federal funds sold and securities purchased under agreements to resell or similar arrangements	0	0
Trading securities	29,485	19,466
Available-for-sale securities	0	0
Mortgage loans held for sale, at lower of cost or fair value	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	64,438	57,431
Financial liabilities [Abstract]
Federal Funds Purchased and Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	0	0
Derivatives 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	10,600	16,600
Federal funds sold and securities purchased under agreements to resell or similar arrangements	27,350	30,950
Trading securities	9,025	9,008
Available-for-sale securities	11,799	15,574
Mortgage loans held for sale, at lower of cost or fair value	157	169
Mortgage loans held for investment, at fair value	2,702,526	2,687,759
Advances to lenders	3,902	5,079
Derivatives assets at fair value	4,729	6,489
Guaranty assets and buy-ups	0	0
Total Financial assets	2,770,088	2,771,628
Financial liabilities [Abstract]
Federal Funds Purchased and Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	62	50
Derivatives liabilities at fair value	9,042	10,671
Guaranty obligations	0	0
Total Financial liabilities	3,224,091	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	1,398	3,030
Available-for-sale securities	8,431	15,080
Mortgage loans held for sale, at lower of cost or fair value	5,541	169
Mortgage loans held for investment, at fair value	351,355	400,327
Advances to lenders	394	470
Derivatives assets at fair value	189	182
Guaranty assets and buy-ups	544	616
Total Financial assets	367,852	419,874
Financial liabilities [Abstract]
Federal Funds Purchased and Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	0	0
Derivatives liabilities at fair value	32	137
Guaranty obligations	1,012	1,579
Total Financial liabilities	30,061	23,592
Carrying Value [Member]
Financial assets [Abstract]
Cash and cash equivalents and restricted cash	45,553	54,565
Federal funds sold and securities purchased under agreements to resell or similar arrangements	27,350	30,950
Trading securities	39,908	31,504
Available-for-sale securities	20,230	30,654
Mortgage loans held for sale, at lower of cost or fair value	5,361	331
Mortgage loans held for investment, at fair value	3,014,283	3,019,163
Advances to lenders	4,308	5,559
Derivatives assets at fair value	894	1,485
Guaranty assets and buy-ups	184	210
Total Financial assets	3,158,071	3,174,421
Financial liabilities [Abstract]
Federal Funds Purchased and Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	62	50
Derivatives liabilities at fair value	424	614
Guaranty obligations	329	382
Total Financial liabilities	3,198,486	3,223,201
Estimate of Fair Value Measurement [Member]
Financial assets [Abstract]
Cash and cash equivalents and restricted cash	45,553	54,565
Federal funds sold and securities purchased under agreements to resell or similar arrangements	27,350	30,950
Trading securities	39,908	31,504
Available-for-sale securities	20,230	30,654
Mortgage loans held for sale, at lower of cost or fair value	5,698	338
Mortgage loans held for investment, at fair value	3,053,881	3,088,086
Advances to lenders	4,296	5,549
Derivatives assets at fair value	894	1,485
Guaranty assets and buy-ups	544	616
Total Financial assets	3,198,354	3,243,747
Financial liabilities [Abstract]
Federal Funds Purchased and Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	62	50
Derivatives liabilities at fair value	424	614
Guaranty obligations	1,012	1,579
Total Financial liabilities	3,245,502	3,312,687
Fannie Mae [Member]
Financial liabilities [Abstract]
Long-term debt, fair value	11,133	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, fair value	0	0
Fannie Mae [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	26,544	29,896
Financial liabilities [Abstract]
Short-term debt	71,006	105,022
Long-term debt, fair value	324,248	367,703
Fannie Mae [Member] | Significant Unobservable Inputs (Level 3) [Member]
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	193,670	217,064
Financial liabilities [Abstract]
Short-term debt	0	0
Long-term debt, fair value	898	982
Fannie Mae [Member] | Carrying Value [Member]
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	206,544	239,243
Financial liabilities [Abstract]
Short-term debt	71,007	105,012
Long-term debt, fair value	315,128	355,431
Fannie Mae [Member] | Estimate of Fair Value Measurement [Member]
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	220,214	246,960
Financial liabilities [Abstract]
Short-term debt	71,006	105,022
Long-term debt, fair value	325,146	368,685
Consolidated Trusts [Member]
Financial liabilities [Abstract]
Long-term debt, fair value	23,609	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, fair value	0	0
Consolidated Trusts [Member] | Significant Other Observable Inputs (Level 2) [Member]
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	2,675,982	2,657,863
Financial liabilities [Abstract]
Short-term debt	0	0
Long-term debt, fair value	2,819,733	2,815,843
Consolidated Trusts [Member] | Significant Unobservable Inputs (Level 3) [Member]
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	157,685	183,263
Financial liabilities [Abstract]
Short-term debt	944	1,560
Long-term debt, fair value	27,175	19,334
Consolidated Trusts [Member] | Carrying Value [Member]
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	2,807,739	2,779,920
Financial liabilities [Abstract]
Short-term debt	943	1,560
Long-term debt, fair value	2,810,593	2,760,152
Consolidated Trusts [Member] | Estimate of Fair Value Measurement [Member]
Financial assets [Abstract]
Mortgage loans held for investment, at fair value	2,833,667	2,841,126
Financial liabilities [Abstract]
Short-term debt	944	1,560
Long-term debt, fair value	$ 2,846,908	$ 2,835,177

Fair Value Option (Details)

Fair Value Option (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Option, Quantitative Disclosures [Line Items]
Mortgage loans held for investment, at fair value	$ 14,075	$ 15,629
Fair value of nonaccrual loans	238	240
Difference between unpaid principal balance and the fair value of nonaccrual loans	59	75
Fair value of loans that are 90 days past due	256	271
Difference between unpaid principal balance and the fair value of these 90 days or more days past due loans	$ 52	78
Single-Family [Member] | Minimum [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Serious delinquency: days past due	90 days
Consolidated Trusts [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Long-term debt, fair value	$ 23,609	19,483
Fannie Mae [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Long-term debt, fair value	11,133	6,403
Loans [Member] | Consolidated Trusts [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Mortgage loans held for investment, at fair value	14,075	15,629
Loans, Unpaid principal balance	13,661	15,001
Long-term Debt [Member] | Consolidated Trusts [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Long-term debt, fair value	23,609	19,483
Long-Term Debt, Unpaid principal balance	21,604	17,810
Long-term Debt [Member] | Fannie Mae [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Long-term debt, fair value	11,133	6,403
Long-Term Debt, Unpaid principal balance	$ 11,263	$ 6,512

Fair Value Changes in FV under

Fair Value Changes in FV under the FV Option (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Option, Quantitative Disclosures [Line Items]
Changes in instrument-specific credit risk	$ 125	$ 276	$ (173)
Other changes in fair value	(45)	165	(384)
Fair value (losses) gains, net	80	441	(557)
Loans [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Changes in instrument-specific credit risk - Loans	86	60	(142)
Other changes in fair value	(191)	670	(730)
Fair value (losses) gains, net	(105)	730	(872)
Long-term Debt [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Changes in instrument-specific credit risk - Long-Term Debt	39	216	(31)
Other changes in fair value	146	(505)	346
Fair value (losses) gains, net	$ 185	$ (289)	$ 315

Commitments and Contingencie121

Commitments and Contingencies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]
Rent expenses for operating leases	$ 47	$ 43	$ 41

Commitments and Contingencies F

Commitments and Contingencies Fiscal Year Maturity Schedule (Details) $ in Millions	Dec. 31, 2015USD ($)
Loans and Mortgage-Related Securities [Abstract]
2,016	$ 58,715
2,017	0
2,018	0
2,019	0
2,020	0
Thereafter	0
Total	58,715
Operating Leases [Abstract]
2,016	44
2,017	46
2,018	32
2,019	49
2,020	53
Thereafter	718
Total	942
Other [Abstract]
2,016	59
2,017	15
2,018	11
2,019	5
2,020	4
Thereafter	0
Total	94
Mortgage commitment derivatives [Member]
Loans and Mortgage-Related Securities [Abstract]
Total	$ 58,500

Selected Quarterly Financial123

Selected Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Interest income:
Trading securities	$ 114	$ 99	$ 116	$ 115	$ 132	$ 151	$ 143	$ 127	$ 444	$ 553	$ 779
Available-for-sale securities	225	261	294	376	373	395	414	440	1,156	1,622	2,357
Mortgage loans interest income	26,993	26,980	26,682	27,044	27,588	27,779	28,165	28,588	107,699	112,120	114,238
Other	39	37	34	33	33	29	24	24	143	110	175
Total interest income	27,371	27,377	27,126	27,568	28,126	28,354	28,746	29,179	109,442	114,405	117,549
Interest expense:
Short-term debt interest expense	47	37	33	29	27	26	21	20	146	94	131
Long-term debt interest expense	22,247	21,752	21,416	22,472	22,957	23,144	23,821	24,421	87,887	94,343	95,014
Total interest expense	22,294	21,789	21,449	22,501	22,984	23,170	23,842	24,441	88,033	94,437	95,145
Net interest income (loss)	5,077	5,588	5,677	5,067	5,142	5,184	4,904	4,738	21,409	19,968	22,404
Benefit (provision) for credit losses	(255)	1,550	(1,033)	533	466	1,085	1,639	774	795	3,964	8,949
Net interest income after benefit (provision) for credit losses	4,822	7,138	4,644	5,600	5,608	6,269	6,543	5,512	22,204	23,932	31,353
Investment gains, net	181	299	514	342	187	171	483	95	1,336	936	1,127
Fair value gains (losses), net	135	(2,589)	2,606	(1,919)	(2,502)	(207)	(934)	(1,190)	(1,767)	(4,833)	2,959
Fee and other income	225	259	556	308	323	826	383	4,355	1,348	5,887	3,930
Non-interest income (loss)	541	(2,031)	3,676	(1,269)	(1,992)	790	(68)	3,260	917	1,990	8,016
Administrative expenses:
Salaries and employee benefits	320	317	331	351	340	337	319	325	1,319	1,321	1,218
Professional services	243	219	251	271	296	263	275	242	984	1,076	910
Occupancy expenses	53	43	43	43	59	47	47	50	182	203	189
Other administrative expenses	70	373	64	58	7	59	56	55	565	177	228
Total administrative expenses	686	952	689	723	702	706	697	672	3,050	2,777	2,545
Foreclosed property expense (income)	477	497	182	473	369	249	(214)	(262)	1,629	142	(2,839)
TCCA fees	429	413	397	382	367	351	335	322	1,621	1,375	1,001
Other expenses (income), net	201	215	202	(5)	48	61	238	131
Total expenses	1,793	2,077	1,470	1,573	1,486	1,367	1,056	863	6,913	4,772	802
Income before federal income taxes	3,570	3,030	6,850	2,758	2,130	5,692	5,419	7,909	16,208	21,150	38,567
Provision for federal income taxes	(1,103)	(1,070)	(2,210)	(870)	(818)	(1,787)	(1,752)	(2,584)	(5,253)	(6,941)	45,415
Net income	2,467	1,960	4,640	1,888	1,312	3,905	3,667	5,325	10,955	14,209	83,982
Less: Net income attributable to noncontrolling interest	(1)	0	0	0	0	0	(1)	0	(1)	(1)	(19)
Net income attributable to Fannie Mae	2,466	1,960	4,640	1,888	1,312	3,905	3,666	5,325	10,954	14,208	83,963
Dividends distributed or available for distribution to senior preferred stockholder	(2,859)	(2,202)	(4,359)	(1,796)	(1,920)	(3,999)	(3,712)	(5,692)	(11,216)	(15,323)	(85,419)
Net income (loss) attributable to common stockholders (Note 11)	$ (393)	$ (242)	$ 281	$ 92	$ (608)	$ (94)	$ (46)	$ (367)	$ (262)	$ (1,115)	$ (1,456)
Earnings (loss) per share: Basic and Diluted (in dollars per share)	$ (0.07)	$ (0.04)	$ 0.05	$ 0.02	$ (0.11)	$ (0.02)	$ (0.01)	$ (0.06)	$ (0.05)	$ (0.19)	$ (0.25)
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	5,893
Weighted-average common shares outstanding: Basic and Diluted					5,762	5,762	5,762	5,762	5,762	5,762	5,762