Federal National Mortgage Association (FNMA) 10-Q1 May 192019 Q1 Quarterly reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information	3 Months Ended
Document and Entity Information	Mar. 31, 2019shares
Entity [Abstract]
Entity Registrant Name	FEDERAL NATIONAL MORTGAGE ASSOCIATION FANNIE MAE
Entity Central Index Key	0000310522
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding	1,158,087,567

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Assets:
Cash and cash equivalents	$ 27,496	$ 25,557
Restricted cash (includes $19,216 and $17,849, respectively, related to consolidated trusts)	24,745	23,866
Federal funds sold and securities purchased under agreements to resell or similar arrangements	22,250	32,938
Investments in securities:
Trading, at fair value (includes $2,922 and $3,061, respectively, pledged as collateral)	40,899	41,867
Available-for-sale, at fair value	3,214	3,429
Total investments in securities	44,113	45,296
Mortgage loans:
Loans held for sale, at lower of cost or fair value	10,066	7,701
Loans held for investment, at amortized cost	3,262,931	3,255,897
Allowance for loan losses	(13,232)	(14,203)
Total loans held for investment, net of allowance	3,249,699	3,241,694
Total mortgage loans	3,259,765	3,249,395
Deferred tax assets, net	13,411	13,188
Accrued interest receivable, net (includes $8,390 and $7,928, respectively, related to consolidated trusts)	8,926	8,490
Acquired property, net	2,489	2,584
Other assets	17,839	17,004
Total assets	3,421,034	3,418,318
Liabilities:
Accrued interest payable (includes $9,221 and $9,133, respectively, related to consolidated trusts)	10,364	10,211
Other liabilities (includes $343 and $356, respectively, related to consolidated trusts)	10,299	9,947
Total liabilities	3,415,673	3,412,078
Commitments and contingencies (Note 14)	0	0
Fannie Mae stockholders’ equity (deficit):
Senior preferred stock, 1,000,000 shares issued and outstanding	120,836	120,836
Preferred stock, 700,000,000 shares are authorized—555,374,922 shares issued and outstanding	19,130	19,130
Common stock, no par value, no maximum authorization—1,308,762,703 shares issued and 1,158,087,567 shares outstanding	687	687
Accumulated deficit	(128,175)	(127,335)
Accumulated other comprehensive income	283	322
Treasury stock, at cost, 150,675,136 shares	(7,400)	(7,400)
Total stockholders’ equity (See Note 1: Senior Preferred Stock Purchase Agreement and Senior Preferred Stock for information on our dividend obligation to Treasury)	5,361	6,240
Total liabilities and equity	3,421,034	3,418,318
Fannie Mae [Member]
Mortgage loans:
Loans held for investment, at amortized cost	105,889	113,039
Liabilities:
Debt (includes $6,682 and $6,826, respectively, of debt of Fannie Mae at fair value and $23,050 and $23,753, respectively, of debt of consolidated trusts, at fair value)	221,238	232,074
Consolidated Trusts [Member]
Assets:
Restricted cash (includes $19,216 and $17,849, respectively, related to consolidated trusts)	19,216	17,849
Mortgage loans:
Loans held for investment, at amortized cost	3,157,042	3,142,858
Accrued interest receivable, net (includes $8,390 and $7,928, respectively, related to consolidated trusts)	8,390	7,928
Liabilities:
Accrued interest payable (includes $9,221 and $9,133, respectively, related to consolidated trusts)	9,221	9,133
Debt (includes $6,682 and $6,826, respectively, of debt of Fannie Mae at fair value and $23,050 and $23,753, respectively, of debt of consolidated trusts, at fair value)	3,173,772	3,159,846
Other liabilities (includes $343 and $356, respectively, related to consolidated trusts)	$ 343	$ 356

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Interest income:
Trading securities	$ 427	$ 236
Available-for-sale securities	53	71
Mortgage loans (includes $28,445 and $26,298, respectively, related to consolidated trusts)	29,768	28,034
Federal funds sold and securities purchased under agreements to resell or similar arrangements	263	142
Other	32	31
Total interest income	30,543	28,514
Interest expense:
Short-term debt	(125)	(107)
Long-term debt (includes $24,189 and $21,715, respectively, related to consolidated trusts)	(25,685)	(23,175)
Total interest expense	(25,810)	(23,282)
Net interest income	4,733	5,232
Benefit for credit losses	650	217
Net interest income after benefit for credit losses	5,383	5,449
Non-interest income (loss):
Investment gains, net	133	250
Fair value gains (losses), net	(831)	1,045
Fee and other income	227	320
Non-interest income (loss)	(471)	1,615
Administrative expenses:
Salaries and employee benefits	(386)	(381)
Professional services	(225)	(243)
Other administrative expenses	(133)	(126)
Total administrative expenses	(744)	(750)
Foreclosed property expense	(140)	(162)
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees	(593)	(557)
Other expenses, net	(408)	(203)
Total expenses	(1,885)	(1,672)
Income before federal income taxes	3,027	5,392
Provision for federal income taxes	(627)	(1,131)
Other comprehensive loss:
Changes in unrealized gains on available-for-sale securities, net of reclassification adjustments and taxes	(36)	(320)
Other, net of taxes	(3)	(3)
Total other comprehensive loss	(39)	(323)
Total comprehensive income	2,361	3,938
Net income	2,400	4,261
Dividends distributed or available for distribution to senior preferred stockholder	(2,361)	(938)
Net income attributable to common stockholders	$ 39	$ 3,323
Earnings per share, Basic	$ 0.01	$ 0.58
Earnings per share, Diluted	$ 0.01	$ 0.56
Weighted-average common shares outstanding, Basic	5,762	5,762
Weighted-average common shares outstanding, Diluted	5,893	5,893

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Assets:
Restricted cash (includes $19,216 and $17,849, respectively, related to consolidated trusts)	$ 24,745	$ 23,866
Investments in securities:
Trading, at fair value (includes $2,922 and $3,061, respectively, pledged as collateral)	2,922	3,061
Available-for-sale, at fair value	3,214	3,429
Accrued interest receivable, net (includes $8,390 and $7,928, respectively, related to consolidated trusts)	8,926	8,490
Mortgage loans:
Total loans held for investment (includes $8,753 and $8,922, respectively, at fair value)	8,752	8,922
Liabilities:
Accrued interest payable (includes $9,221 and $9,133, respectively, related to consolidated trusts)	10,364	10,211
Other liabilities (includes $343 and $356, respectively, related to consolidated trusts)	$ 10,299	$ 9,947
Fannie Mae stockholders’ equity (deficit):
Senior preferred stock, 1,000,000 shares issued	1,000,000	1,000,000
Senior preferred stock, 1,000,000 shares outstanding	1,000,000	1,000,000
Preferred stock, 700,000,000 shares are authorized	700,000,000	700,000,000
Preferred stock, 555,374,922 shares issued	555,374,922	555,374,922
Preferred stock, 555,374,922 shares outstanding	555,374,922	555,374,922
Common stock, 1,308,762,703 shares issued	1,308,762,703	1,308,762,703
Common stock, 1,158,087,567 shares outstanding	1,158,087,567	1,158,087,567
Treasury stock, at cost, 150,675,136 shares	150,675,136	150,675,136
Consolidated Trusts [Member]
Assets:
Restricted cash (includes $19,216 and $17,849, respectively, related to consolidated trusts)	$ 19,216	$ 17,849
Investments in securities:
Accrued interest receivable, net (includes $8,390 and $7,928, respectively, related to consolidated trusts)	8,390	7,928
Liabilities:
Accrued interest payable (includes $9,221 and $9,133, respectively, related to consolidated trusts)	9,221	9,133
Debt (includes $6,682 and $6,826, respectively, of debt of Fannie Mae at fair value and $23,050 and $23,753, respectively, of debt of consolidated trusts, at fair value)	23,050	23,753
Other liabilities (includes $343 and $356, respectively, related to consolidated trusts)	343	356
Fannie Mae [Member]
Liabilities:
Debt (includes $6,682 and $6,826, respectively, of debt of Fannie Mae at fair value and $23,050 and $23,753, respectively, of debt of consolidated trusts, at fair value)	$ 6,682	$ 6,826

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Mortgage loans (includes $28,445 and $26,298, respectively, related to consolidated trusts)	$ 29,768	$ 28,034
Long-term debt (includes $24,189 and $21,715, respectively, related to consolidated trusts)	25,685	23,175
Consolidated Trusts [Member]
Mortgage loans (includes $28,445 and $26,298, respectively, related to consolidated trusts)	28,445	26,298
Long-term debt (includes $24,189 and $21,715, respectively, related to consolidated trusts)	$ 24,189	$ 21,715

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net cash provided by (used in) operating activities
Net cash provided by (used in) operating activities	$ 1,816	$ (1,409)
Cash flows provided by investing activities:
Proceeds from maturities and paydowns of trading securities held for investment	15	110
Proceeds from sales of trading securities held for investment	49	0
Proceeds from maturities and paydowns of available-for-sale securities	113	266
Proceeds from sales of available-for-sale securities	131	648
Purchases of loans held for investment	(33,631)	(40,045)
Advances to lenders	(22,991)	(27,898)
Proceeds from disposition of acquired property and preforeclosure sales	1,965	2,360
Net change in federal funds sold and securities purchased under agreements to resell or similar arrangements	10,688	(20,231)
Other, net	(124)	(264)
Net cash provided by investing activities	47,446	15,816
Cash flows used in financing activities:
Payments of cash dividends on senior preferred stock to Treasury	(3,240)	0
Proceeds from senior preferred stock purchase agreement with Treasury	0	3,687
Other, net	0	442
Net cash used in financing activities	(46,444)	(37,307)
Net increase (decrease) in cash, cash equivalents and restricted cash	2,818	(22,900)
Cash, cash equivalents and restricted cash at beginning of period	49,423	60,260
Cash, cash equivalents and restricted cash at end of period	52,241	37,360
Cash paid during the period for:
Interest	28,650	27,041
Income taxes	0	0
Fannie Mae [Member]
Cash flows provided by investing activities:
Proceeds from repayments of loans acquired as held for investment	2,786	4,164
Proceeds from sales of loans acquired as held for investment of Fannie Mae	26	80
Cash flows used in financing activities:
Proceeds from issuance of debt	173,122	288,281
Payments to redeem debt	(184,222)	(299,797)
Consolidated Trusts [Member]
Cash flows provided by investing activities:
Proceeds from repayments of loans acquired as held for investment	88,419	96,626
Cash flows used in financing activities:
Proceeds from issuance of debt	64,821	89,493
Payments to redeem debt	$ (96,925)	$ (119,413)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Changes in Equity (Deficit) - USD ($) $ in Millions	Total	Senior Preferred Stock	Preferred Stock	Common Stock	Accumulated Deficit	Accumulated Other Comprehensive Income	Treasury Stock
Proceeds From Senior Preferred Stock Agreement With Us Treasury	$ 3,687	$ 3,687
Balance (shares) at Dec. 31, 2017		1,000,000	556,000,000	1,158,000,000
Balance at Dec. 31, 2017	(3,686)	$ 117,149	$ 19,130	$ 687	$ (133,805)	$ 553	$ (7,400)
Increase (Decrease) in Stockholders' Equity [Rollforward]
Preferred Stock, Dividends, Per Share, Cash Paid	0
Increase to senior preferred stock		3,687
Comprehensive income:
Net income	4,261				4,261
Other comprehensive income (loss), net of tax effect:
Changes in net unrealized gains on available-for-sale securities (net of tax of $2 and $15, respectively)	(57)					(57)
Reclassification adjustment for gains included in net income (net of tax of $12, and $70, respectively)	(263)					(263)
Prior service cost and actuarial gains, net of amortization for defined benefit plans (net of tax)	(3)					(3)
Reclassification related to Tax Cuts and Jobs Act					(117)	117
Other	(1)				(1)
Balance at Mar. 31, 2018	(3,938)	$ 120,836	$ 19,130	$ 687	(129,662)	(347)	(7,400)
Balance (shares) at Mar. 31, 2018		1,000,000	556,000,000	1,158,000,000
Balance (shares) at Dec. 31, 2017		1,000,000	556,000,000	1,158,000,000
Balance at Dec. 31, 2017	(3,686)	$ 117,149	$ 19,130	$ 687	(133,805)	553	(7,400)
Other comprehensive income (loss), net of tax effect:
Total comprehensive income	3,938
Balance at Dec. 31, 2018	$ 6,240	$ 120,836	$ 19,130	$ 687	(127,335)	322	(7,400)
Balance (shares) at Dec. 31, 2018		1,000,000	556,000,000	1,158,000,000
Other comprehensive income (loss), net of tax effect:
Senior preferred stock issued, shares	1,000,000
Proceeds From Senior Preferred Stock Agreement With Us Treasury	$ 0
Preferred Stock, Dividends, Per Share, Cash Paid	3,240				3,240
Net income	2,400				2,400
Changes in net unrealized gains on available-for-sale securities (net of tax of $2 and $15, respectively)	8					8
Reclassification adjustment for gains included in net income (net of tax of $12, and $70, respectively)	(44)					(44)
Prior service cost and actuarial gains, net of amortization for defined benefit plans (net of tax)	(3)					(3)
Total comprehensive income	2,361
Reclassification related to Tax Cuts and Jobs Act						0
Balance at Mar. 31, 2019	$ 5,361	$ 120,836	$ 19,130	$ 687	$ (128,175)	$ 283	$ (7,400)
Balance (shares) at Mar. 31, 2019		1,000,000	556,000,000	1,158,000,000
Other comprehensive income (loss), net of tax effect:
Senior preferred stock issued, shares	1,000,000

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity (Deficit) (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, Tax	$ (2)	$ 15
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax	12	$ 70
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Plan Amendments, Tax Effect	$ 1
Senior Preferred Stock
Preferred Stock, Dividends, Per Share, Cash Paid	$ 3,240.33

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies 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, 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 have been under conservatorship, with FHFA acting as conservator, since September 6, 2008. See “Note 1, Summary of Significant Accounting Policies” in our annual report on Form 10-K for the year ended December 31, 2018 (“ 2018 Form 10-K”) for additional information on our conservatorship and the impact of U.S. government support of our business. The unaudited interim condensed consolidated financial statements as of and for the three months ended March 31, 2019 and related notes, should be read in conjunction with our audited consolidated financial statements and related notes included in our 2018 Form 10-K. Basis of Presentation The accompanying unaudited interim condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) for interim financial information and with the SEC’s instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and note disclosures required by GAAP for complete consolidated financial statements. In the opinion of management, all adjustments of a normal recurring nature considered necessary for a fair presentation have been included. The accompanying condensed consolidated financial statements include our accounts as well as the accounts of other entities in which we have a controlling financial interest. All intercompany accounts and transactions have been eliminated. To conform to our current period presentation, we have reclassified certain amounts reported in our prior period condensed consolidated financial statements. Results for the three months ended March 31, 2019 may not necessarily be indicative of the results for the year ending December 31, 2019 . Use of Estimates Preparing condensed consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that affect our reported amounts of assets and liabilities, disclosure of contingent assets and liabilities as of the dates of our condensed consolidated financial statements, as well as our reported amounts of revenues and expenses during the reporting periods. Management has made significant estimates in a variety of areas including, but not limited to, the allowance for loan losses. Actual results could be different from these estimates. 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. Treasury has made a commitment under the senior preferred stock purchase agreement to provide funding to us under certain circumstances if we have a net worth deficit. Pursuant to the senior preferred stock purchase agreement, we have received a total of $119.8 billion from Treasury as of March 31, 2019 , and the amount of remaining funding available to us under the agreement was $113.9 billion . Pursuant to the senior preferred stock purchase agreement, we issued shares of senior preferred stock to Treasury in 2008. Acting as successor to the rights, titles, powers and privileges of the Board, our conservator has declared and directed us to pay dividends to Treasury on the senior preferred stock on a quarterly basis for every dividend period for which dividends were payable since we entered conservatorship in 2008. The current dividend provisions of the senior preferred stock provide for quarterly dividends consisting of the amount, if any, by which our net worth as of the end of the immediately preceding fiscal quarter exceeds a $3.0 billion capital reserve amount. We refer to this as a “net worth sweep” dividend. On March 29, 2019 , we paid Treasury a dividend of $3.2 billion based on our net worth of $6.2 billion as of December 31, 2018 , less the applicable capital reserve amount of $3.0 billion . Because we had a net worth of $5.4 billion as of March 31, 2019 , we expect to pay Treasury a dividend of $2.4 billion for the second quarter of 2019 by June 30, 2019 . The liquidation preference of the senior preferred stock is subject to adjustment. The aggregate liquidation preference of the senior preferred stock was $123.8 billion as of March 31, 2019 . See “ Note 11, Equity (Deficit) ” in our 2018 We submit capital reports to FHFA, which monitors our capital levels. The deficit of core capital over statutory minimum capital was $137.8 billion as of March 31, 2019 and $137.1 billion as of December 31, 2018 Because Treasury holds a 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 March 31, 2019 , Treasury held an investment in our senior preferred stock with an aggregate liquidation preference of $123.8 billion . See “Senior Preferred Stock Purchase Agreement and Senior Preferred Stock” section for additional information on transactions under this agreement. FHFA’s control of both Fannie Mae and Freddie Mac has caused Fannie Mae, FHFA and Freddie Mac to be deemed related parties. Additionally, Fannie Mae and Freddie Mac jointly own Common Securitization Solutions, LLC (“CSS”), a limited liability company created to operate a common securitization platform; as such, CSS is deemed a related party. In the ordinary course of business, Fannie Mae may purchase and sell securities issued by Treasury and Freddie Mac. These transactions occur on the same terms as those prevailing at the time for comparable transactions with unrelated parties. Additionally, we make regular income tax payments to and receive tax refunds from the Internal Revenue Service (“IRS”), a bureau of Treasury. Transactions with Treasury Our administrative expenses were reduced by $5 million and $7 million for the three months ended March 31, 2019 and 2018 , respectively, due to reimbursements from Treasury and Freddie Mac for expenses incurred as program administrator for Treasury’s Home Affordable Modification Program and other initiatives under Treasury’s Making Home Affordable Program. In December 2011, Congress enacted the Temporary Payroll Cut Continuation Act of 2011 (“TCCA”) which, among other provisions, required that we increase our single-family guaranty fees by at least 10 basis points and remit this increase to Treasury. Effective April 1, 2012, we increased the guaranty fee on all single-family residential mortgages delivered to us by 10 basis points. FHFA and Treasury 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 condensed consolidated statements of operations and comprehensive income. We recognized $593 million and $557 million in TCCA fees for the three months ended March 31, 2019 and 2018 , respectively, of which $593 million had not been remitted to Treasury as of March 31, 2019 . Under the Federal Housing Enterprises Financial Safety and Soundness Act of 1992, as amended, including by the Federal Housing Finance Regulatory Reform Act of 2008 (together, the “GSE Act”), we are required to set aside certain funding obligations, a portion of which is attributable to Treasury’s Capital Magnet Fund. These expenses, recognized in “Other expenses, net” in our condensed consolidated statements of operations and comprehensive income, were measured as the product of 4.2 basis points and the unpaid principal balance of our total new business purchases for the respective period. We recognized a total of $75 million in “Other expenses, net” in connection with Treasury’s Capital Magnet Fund for the year ended December 31, 2018, which was outstanding as of March 31, 2019 and remitted on April 5, 2019. We recognized $15 million and $18 million in “Other expenses, net” in connection with Treasury’s Capital Magnet Fund for the three months ended March 31, 2019 and 2018 , respectively, of which $15 million had not been remitted as of March 31, 2019 . Transactions with FHFA The GSE Act authorizes FHFA to establish an annual assessment for regulated entities, including Fannie Mae, which is payable on a semi-annual basis (April and October), for FHFA’s costs and expenses, as well as to maintain FHFA’s working capital. We recognized FHFA assessment fees, which are recorded in “Administrative expenses” in our condensed consolidated statements of operations and comprehensive income, of $30 million and $29 million for the three months ended March 31, 2019 and 2018 , respectively. Transactions with CSS We contributed capital to CSS, the company we jointly own with Freddie Mac, of $36 million and $41 million for the three months ended March 31, 2019 and 2018 , respectively. No other transactions outside of normal business activities have occurred between us and CSS during the three months ended March 31, 2019 and 2018 Earnings per share (“EPS”) is presented for basic and diluted EPS. We compute basic EPS by dividing net income attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period. However, as a result of our conservatorship status and the terms of the senior preferred stock, no amounts would be available to distribute as dividends to common or preferred stockholders (other than to Treasury as the holder of the senior preferred stock). Weighted average common shares includes 4.6 billion shares for the periods ended March 31, 2019 and 2018 that would be issued upon the full exercise of the warrant issued to Treasury from the date the warrant was issued through March 31, 2019 and 2018 . The calculation of diluted EPS includes all the components of basic earnings per share, plus the dilutive effect of common stock equivalents such as convertible securities and stock options. Weighted average shares outstanding is increased to include the number of additional common shares that would have been outstanding if the dilutive potential common shares had been issued. For the three months ended March 31, 2019 and 2018 , our diluted EPS weighted average shares outstanding includes shares of common stock that would be issuable upon the conversion of 131 million The following table updates information about our significant accounting policies that have recently been adopted or are yet to be adopted from the information included in “Note 1, Summary of Significant Accounting Policies” in our 2018 Form 10-K. Standard Description Effective Date Impact on Consolidated Financial Statements ASU 2016-02, Leases (Topic 842) The amendment addresses the accounting for lease arrangements. January 1, 2019 We adopted this standard on January 1, 2019. The adoption of this guidance did not have a material impact on our consolidated financial statements. ASU 2017-12 - Derivatives and Hedging (Topic 815) The amendments in this standard made targeted improvements to accounting for hedging activities. The standard changes the recognition and presentation requirements of hedge accounting and provides new alternatives for measuring and accounting for certain aspects of hedging activities. January 1, 2019 This guidance became effective this quarter. Hedge accounting is elective and, while we do not currently have a hedge accounting program, we are developing capabilities to implement hedge accounting to reduce interest rate volatility in our consolidated statements of operations and comprehensive income. ASU 2016-13 , Financial Instruments—Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments (“CECL”) The amendments in this standard replace the incurred loss impairment methodology in current GAAP with a methodology that reflects lifetime expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. January 1, 2020 CECL will become effective for our fiscal year beginning January 1, 2020. We will recognize the impact of the new guidance through a cumulative effect adjustment to retained earnings as of the beginning of the year of adoption. We are continuing to update our allowance models and accounting systems that will be used to estimate credit losses and record accounting impacts under CECL, and we are in the process of validating their results. All updates to our allowance models are subject to our model oversight and review governance process. We expect model and system testing to continue in 2019, followed by full integrated testing across all impacted systems and processes. Implementation of this guidance is being managed in accordance with our change management governance standards, which are designed to ensure compliance with GAAP as well as operational readiness at adoption. We provide updates to senior management and the Audit Committee regarding the status of our implementation plan, results of initial modeled impacts and any identified key risks. We are continuing to evaluate the impact of this guidance on our consolidated financial statements. The adoption of this guidance likely will increase our allowance for credit losses and decrease, perhaps substantially, our retained earnings. We expect the greater impact of the guidance to relate to our accounting for credit losses for loans that are not individually impaired. We do not expect a material impact from the valuation allowance associated with our available for sale securities. However, the impact at adoption will be influenced by the composition and quality of our total book of business at the adoption date, as well as economic conditions and forecasts at that time.

Consolidations and Transfers of

Consolidations and Transfers of Financial Assets	3 Months Ended
Consolidations and Transfers of Financial Assets	Mar. 31, 2019
Consolidations and Transfers of Financial Assets [Abstract]
Consolidations and Transfers of Financial Assets	Consolidations and Transfers of Financial Assets We do not consolidate VIEs when we are not deemed to be the primary beneficiary. Our unconsolidated VIEs include securitization trusts, limited partnerships, and certain SPVs designed to transfer credit risk. The following table displays the carrying amount and classification of our assets and liabilities that relate to our involvement with unconsolidated securitization trusts. As of March 31, 2019 December 31, 2018 Assets and liabilities recorded in our condensed consolidated balance sheets related to mortgage-backed trusts: (Dollars in millions) Assets: Trading securities: Fannie Mae $ 1,543 $ 1,422 Non-Fannie Mae 4,212 4,809 Total trading securities 5,755 6,231 Available-for-sale securities: Fannie Mae 1,660 1,704 Non-Fannie Mae 1,046 1,207 Total available-for-sale securities 2,706 2,911 Other assets 65 66 Other liabilities (97 ) (101 ) Net carrying amount $ 8,429 $ 9,107 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 approximately $13 billion and $14 billion as of March 31, 2019 and December 31, 2018 , respectively. The total assets of our unconsolidated securitization trusts were approximately $70 billion and $80 billion as of March 31, 2019 and December 31, 2018 , respectively. The maximum exposure to loss for our unconsolidated limited partnerships and similar legal entities, which consist of low-income housing tax credit investments (“LIHTC”), community investments and other entities, was $103 million and the related carrying value was $82 million as of March 31, 2019 . As of December 31, 2018 , the maximum exposure to loss was $111 million and the related carrying value was $89 million . The total assets of these limited partnership investments were $2.3 billion as of March 31, 2019 and December 31, 2018 , respectively. The maximum exposure to loss related to our involvement with unconsolidated SPVs that transfer credit risk represents the unpaid principal balance and accrued interest payable of obligations issued by the Connecticut Avenue Securities (“CAS”) SPVs. The maximum exposure to loss related to these unconsolidated special purpose vehicles was $2.9 billion and $920 million as of March 31, 2019 and December 31, 2018 , respectively. The total assets related to these unconsolidated special purpose vehicles were $2.9 billion and $931 million as of March 31, 2019 and December 31, 2018 , respectively. The unpaid principal balance of our multifamily loan portfolio was $302.2 billion as of March 31, 2019 . As our lending relationship does not provide us with a controlling financial interest in the borrower entity, we do not consolidate these borrowers regardless of their status as either a VIE or a voting interest entity. We have excluded these entities from our VIE disclosures. However, the disclosures we have provided in “ Note 3, Mortgage Loans ,” “ Note 4, Allowance for Loan Losses ” and “ Note 6, Financial Guarantees We issue Fannie Mae MBS through portfolio securitization transactions by transferring pools of mortgage loans or mortgage-related securities to one or more trusts or special purpose entities. We are considered to be the transferor when we transfer assets from our own retained mortgage portfolio in a portfolio securitization transaction. For the three months ended March 31, 2019 and 2018 , the unpaid principal balance of portfolio securitizations was $41.4 billion and $64.3 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 March 31, 2019 , the unpaid principal balance of retained interests was $1.6 billion and its related fair value was $2.3 billion . As of December 31, 2018 , the unpaid principal balance of retained interests was $1.5 billion and its related fair value was $2.2 billion . For the three months ended March 31, 2019 and 2018 , the principal, interest and other fees received on retained interests was $116 million and $226 million 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 $1.2 billion as of March 31, 2019 and December 31, 2018 . For information on our on-balance sheet mortgage loans, see “ Note 3, Mortgage Loans

Mortgage Loans

Mortgage Loans	3 Months Ended
Mortgage Loans	Mar. 31, 2019
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Abstract]
Mortgage Loans	Mortgage Loans Investment gains, net ” in our condensed consolidated statements of operations and comprehensive income. We define the recorded investment of HFI loans as unpaid principal balance, net of unamortized premiums and discounts, other cost basis adjustments, and accrued interest receivable. For purposes of the single-family mortgage loan disclosures below, we define “primary” class as mortgage loans that are not included in other loan classes; “government” class as mortgage loans that are guaranteed or insured, in whole or in part, by the U.S. government or one of its agencies, and that are not Alt-A; and “other” class as loans with higher-risk characteristics, such as interest-only loans and negative-amortizing loans, that are neither government nor Alt-A. The following table displays the carrying value of our mortgage loans. As of March 31, 2019 December 31, 2018 (Dollars in millions) Single-family $ 2,930,649 $ 2,929,925 Multifamily 302,152 293,858 Total unpaid principal balance of mortgage loans 3,232,801 3,223,783 Cost basis and fair value adjustments, net 40,196 39,815 Allowance for loan losses for loans held for investment (13,232 ) (14,203 ) Total mortgage loans $ 3,259,765 $ 3,249,395 The following table displays information about our redesignated mortgage loans. For the Three Months Ended March 31, 2019 2018 (Dollars in millions) Carrying value of loans redesignated from HFI to HFS $ 2,611 $ 7,367 Carrying value of loans redesignated from HFS to HFI 9 18 Loans sold - unpaid principal balance 58 748 Realized gains on sale of mortgage loans 36 2 The recorded investment of single-family mortgage loans for which formal foreclosure proceedings are in process was $10.1 billion as of March 31, 2019 and December 31, 2018 . As a result of our various loss mitigation and foreclosure prevention efforts, we expect that a portion of the loans in the process of formal foreclosure proceedings will not ultimately foreclose. Nonaccrual Loans 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 March 31, 2019 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 $ 29,620 $ 7,397 $ 14,601 $ 51,618 $ 2,821,187 $ 2,872,805 $ 24 $ 25,710 Government (2) 48 16 162 226 20,901 21,127 162 — Alt-A 2,470 803 1,779 5,052 45,750 50,802 1 2,998 Other 772 281 676 1,729 11,956 13,685 3 1,080 Total single-family 32,910 8,497 17,218 58,625 2,899,794 2,958,419 190 29,788 Multifamily (3) 3 N/A 193 196 304,201 304,397 — 509 Total $ 32,913 $ 8,497 $ 17,411 $ 58,821 $ 3,203,995 $ 3,262,816 $ 190 $ 30,297 As of December 31, 2018 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 $ 30,471 $ 7,881 $ 14,866 $ 53,218 $ 2,816,047 $ 2,869,265 $ 22 $ 26,170 Government (2) 57 17 169 243 21,887 22,130 169 — Alt-A 2,332 821 1,844 4,997 48,274 53,271 2 3,082 Other 804 283 713 1,800 13,038 14,838 2 1,128 Total single-family 33,664 9,002 17,592 60,258 2,899,246 2,959,504 195 30,380 Multifamily (3) 56 N/A 171 227 295,437 295,664 — 492 Total $ 33,720 $ 9,002 $ 17,763 $ 60,485 $ 3,194,683 $ 3,255,168 $ 195 $ 30,872 (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 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 March 31, 2019 (1) December 31, 2018 (1) Primary Alt-A Other Primary Alt-A Other (Dollars in millions) Estimated mark-to-market loan-to-value (“LTV”) ratio: (2) Less than or equal to 80% $ 2,496,412 $ 43,554 $ 11,362 $ 2,521,766 $ 45,476 $ 12,291 Greater than 80% and less than or equal to 90% 239,373 3,555 1,074 228,614 3,804 1,195 Greater than 90% and less than or equal to 100% 126,992 1,837 584 109,548 1,997 645 Greater than 100% 10,028 1,856 665 9,337 1,994 707 Total $ 2,872,805 $ 50,802 $ 13,685 $ 2,869,265 $ 53,271 $ 14,838 (1) Excludes $21.1 billion and $22.1 billion as of March 31, 2019 and December 31, 2018 , 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 class is primarily reverse mortgages for which we do not calculate an estimated mark-to-market LTV ratio. (2) As of March 31, December 31, 2019 2018 (Dollars in millions) Credit risk profile by internally assigned grade: Non-classified $ 297,312 $ 289,231 Classified (1) 7,085 6,433 Total $ 304,397 $ 295,664 (1) Represents loans classified as “Substandard,” which have a well-defined weakness that jeopardizes the timely full repayment. Loans with a weakness that makes collection or liquidation in full highly questionable and improbable based on existing conditions and values are referred to as “Doubtful.” As of March 31, 2019 , we had loans with recorded investment of less than $0.5 million classified as doubtful, compared with $1 million as of December 31, 2018 Individually impaired loans include troubled debt restructurings (“TDRs”), acquired credit-impaired loans and multifamily loans that we have assessed as probable that we will not collect all contractual amounts due, regardless of whether we are currently accruing interest, excluding loans classified as HFS and loans for which we have elected the fair value option. 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 March 31, 2019 December 31, 2018 Unpaid Principal Balance Total Recorded Investment Related Allowance for Loan Losses Unpaid Principal Balance Total Recorded Investment Related Allowance for Loan Losses (Dollars in millions) Individually impaired loans: With related allowance recorded: Single-family: Primary $ 79,713 $ 76,804 $ (8,816 ) $ 81,791 $ 78,688 $ (9,406 ) Government 265 270 (55 ) 264 270 (55 ) Alt-A 15,486 14,178 (2,526 ) 16,576 15,158 (2,793 ) Other 4,987 4,706 (894 ) 5,482 5,169 (1,001 ) Total single-family 100,451 95,958 (12,291 ) 104,113 99,285 (13,255 ) Multifamily 297 298 (44 ) 197 196 (40 ) Total individually impaired loans with related allowance recorded 100,748 96,256 (12,335 ) 104,310 99,481 (13,295 ) With no related allowance recorded: (1) Single-family: Primary 16,089 15,325 — 15,939 15,191 — Government 61 57 — 61 56 — Alt-A 2,508 2,248 — 2,628 2,363 — Other 688 635 — 718 666 — Total single-family 19,346 18,265 — 19,346 18,276 — Multifamily 360 361 — 343 346 — Total individually impaired loans with no related allowance recorded 19,706 18,626 — 19,689 18,622 — Total individually impaired loans (2) $ 120,454 $ 114,882 $ (12,335 ) $ 123,999 $ 118,103 $ (13,295 ) (1) The discounted cash flows or collateral value equals or exceeds the carrying value of the loan and, as such, no valuation allowance is required. (2) Includes single-family loans restructured in a TDR with a recorded investment of $113.9 billion and $117.2 billion as of March 31, 2019 and December 31, 2018 , respectively. Includes multifamily loans restructured in a TDR with a recorded investment of $188 million and $187 million as of March 31, 2019 and December 31, 2018 , respectively. For the Three Months Ended March 31, 2019 2018 Average Recorded Investment Total Interest Income Recognized Interest Income Recognized on a Cash Basis Average Recorded Investment Total Interest Income Recognized Interest Income Recognized on a Cash Basis (Dollars in millions) Individually impaired loans: With related allowance recorded: Single-family: Primary $ 77,842 $ 817 $ 80 $ 88,411 $ 911 $ 107 Government 272 3 — 276 3 — Alt-A 14,687 156 11 20,708 212 16 Other 4,940 45 4 7,854 71 5 Total single-family 97,741 1,021 95 117,249 1,197 128 Multifamily 247 2 — 258 — — Total individually impaired loans with related allowance recorded 97,988 1,023 95 117,507 1,197 128 With no related allowance recorded: (1) Single-family: Primary 15,195 220 28 15,007 243 26 Government 56 1 — 60 — — Alt-A 2,293 39 2 2,842 58 4 Other 648 8 1 900 16 1 Total single-family 18,192 268 31 18,809 317 31 Multifamily 353 2 — 331 2 — Total individually impaired loans with no related allowance recorded 18,545 270 31 19,140 319 31 Total individually impaired loans $ 116,533 $ 1,293 $ 126 $ 136,647 $ 1,516 $ 159 (1) 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 157 months and 144 months for the three months ended March 31, 2019 and 2018 , respectively. The average interest rate reduction was 0.10 and 0.31 percentage points, for the three months ended March 31, 2019 and 2018 , respectively. The following table displays the number of loans and recorded investment in loans classified as a TDR. For the Three Months Ended March 31, 2019 2018 Number of Loans Recorded Investment (1) Number of Loans Recorded Investment (1) (Dollars in millions) Single-family: Primary 12,957 $ 1,971 41,679 $ 6,524 Government 23 4 48 4 Alt-A 766 97 2,182 283 Other 147 27 445 84 Total single-family 13,893 2,099 44,354 6,895 Multifamily 3 13 8 42 Total TDRs 13,896 $ 2,112 44,362 $ 6,937 (1) Based on the nature of our modification programs, which do not include principal or past-due interest forgiveness, there is not a material difference between the recorded investment in our loans pre- and post- modification. Therefore, these amounts represent recorded investment post-modification. The decrease in loans classified as a TDR for the three months ended March 31, 2019 compared with the three months ended March 31, 2018 For the Three Months Ended March 31, 2019 2018 Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 4,516 $ 673 4,818 $ 701 Government 18 3 14 2 Alt-A 471 73 677 109 Other 154 28 195 38 Total single-family 5,159 777 5,704 850 Multifamily — — 1 2 Total TDRs that subsequently defaulted 5,159 $ 777 5,705 $ 852

Allowance for Loan Losses

Allowance for Loan Losses	3 Months Ended
Allowance for Loan Losses	Mar. 31, 2019
Receivables [Abstract]
Allowance for Loan Losses	Allowance for Loan Losses We aggregate single-family HFI loans that are not individually impaired based on similar risk characteristics, for purposes of estimating incurred credit losses and establishing a collective single-family loss reserve using an econometric model that derives an overall loss reserve estimate. We base our allowance methodology on historical events and trends, such as loss severity (in event of default), default rates, and recoveries from mortgage insurance contracts and other credit enhancements that provide loan level loss coverage and are either contractually attached to a loan or that were entered into contemporaneously with and in contemplation of a guaranty or loan purchase transaction. We use recent regional historical sales and appraisal information, including the sales of our own foreclosed properties, to develop our loss severity estimates for all loan categories. Our allowance calculation also incorporates a loss confirmation period (the anticipated time lag between a credit loss event and the confirmation of the credit loss resulting from that event) to ensure our allowance estimate captures credit losses that have been incurred as of the balance sheet date but have not been confirmed. In addition, management performs a review of the observable data used in its estimate to ensure it is representative of prevailing economic conditions and other events existing as of the balance sheet date. Individually impaired single-family loans currently include those classified as a TDR and acquired credit-impaired loans. We consider a loan to be impaired when, based on current information, it is probable that we will not receive all amounts due, including interest, in accordance with the contractual terms of the loan agreement. When a loan has been restructured, we measure impairment using a cash flow analysis discounted at the loan’s original effective interest rate. If we expect to recover our recorded investment in an individually impaired loan through probable foreclosure of the underlying collateral, we measure impairment based on the 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. We establish a collective allowance for all loans in our multifamily guaranty book of business that are not individually measured for impairment using an internal model that applies loss factors to loans in similar risk categories. Our loss factors are developed based on our historical default and loss severity experience. We identify multifamily loans for evaluation for impairment through a credit risk assessment process. If we determine that a multifamily loan is individually impaired, we generally measure impairment on that loan based on the fair value of the underlying collateral less estimated costs to sell the property, as we have concluded that such loans are collateral dependent. We evaluate collectively for impairment smaller-balance homogeneous multifamily loans. The following table displays changes in single-family, multifamily and total allowance for loan losses. For the Three Months Ended March 31, 2019 2018 (Dollars in millions) Single-family allowance for loan losses: Beginning balance $ (13,969 ) $ (18,849 ) Benefit (provision) for loan losses (1) 647 (78 ) Charge-offs 381 465 Recoveries (45 ) (60 ) Other 1 (1 ) Ending balance $ (12,985 ) $ (18,523 ) Multifamily allowance for loan losses: Beginning balance $ (234 ) $ (235 ) Benefit (provision) for loan losses (1) (13 ) 20 Charge-offs — 4 Ending balance $ (247 ) $ (211 ) Total allowance for loan losses: Beginning balance $ (14,203 ) $ (19,084 ) Benefit (provision) for loan losses (1) 634 (58 ) Charge-offs 381 469 Recoveries (45 ) (60 ) Other 1 (1 ) Ending balance $ (13,232 ) $ (18,734 ) (1) Benefit (provision) for loan losses is included in “ Benefit for credit losses As of March 31, 2019 December 31, 2018 Single-Family Multifamily Total Single-Family Multifamily Total (Dollars in millions) Allowance for loan losses by segment: Individually impaired loans (1) $ (12,291 ) $ (44 ) $ (12,335 ) $ (13,255 ) $ (40 ) $ (13,295 ) Collectively reserved loans (694 ) (203 ) (897 ) (714 ) (194 ) (908 ) Total allowance for loan losses $ (12,985 ) $ (247 ) $ (13,232 ) $ (13,969 ) $ (234 ) $ (14,203 ) Recorded investment in loans by segment: Individually impaired loans (1) $ 114,223 $ 659 $ 114,882 $ 117,561 $ 542 $ 118,103 Collectively reserved loans 2,844,196 303,738 3,147,934 2,841,943 295,122 3,137,065 Total recorded investment in loans $ 2,958,419 $ 304,397 $ 3,262,816 $ 2,959,504 $ 295,664 $ 3,255,168 (1)

Investments in Securities

Investments in Securities	3 Months Ended
Investments in Securities	Mar. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Investments in Securities	Investments in Securities Trading securities are recorded at fair value with subsequent changes in fair value recorded as “ Fair value gains (losses), net ” in our condensed consolidated statements of operations and comprehensive income. The following table displays our investments in trading securities. As of March 31, 2019 December 31, 2018 (Dollars in millions) Mortgage-related securities: Fannie Mae $ 1,583 $ 1,467 Other agency 3,158 3,503 Private-label and other mortgage securities 1,054 1,306 Total mortgage-related securities 5,795 6,276 Non-mortgage-related securities: U.S. Treasury securities 35,020 35,502 Other securities 84 89 Total non-mortgage-related securities 35,104 35,591 Total trading securities $ 40,899 $ 41,867 For the Three Months Ended March 31, 2019 2018 (Dollars in millions) Net trading gains $ 92 $ 98 Net trading gains recognized in the period related to securities still held at period end 89 76 We record available-for-sale (“AFS”) securities at fair value with unrealized gains and losses, recorded net of tax, as a component of “Other comprehensive loss” and we recognize realized gains and losses from the sale of AFS securities in “ Investment gains, net ” in our condensed consolidated statements of operations and comprehensive income. The following table displays the gross realized gains and proceeds on sales of AFS securities. For the Three Months Ended March 31, 2019 2018 (Dollars in millions) Gross realized gains $ 61 $ 363 Total proceeds (excludes initial sale of securities from new portfolio securitizations) 131 635 As of March 31, 2019 Total Amortized Cost (1) Gross Unrealized Gains Gross Unrealized Losses (2) Total Fair Value (Dollars in millions) Fannie Mae $ 1,689 $ 82 $ (19 ) $ 1,752 Other agency 225 17 — 242 Alt-A and subprime private-label securities 246 206 — 452 Mortgage revenue bonds 416 13 (4 ) 425 Other mortgage-related securities 334 9 — 343 Total $ 2,910 $ 327 $ (23 ) $ 3,214 As of December 31, 2018 Total Amortized Cost (1) Gross Unrealized Gains Gross Unrealized Losses (2) Total Fair Value (Dollars in millions) Fannie Mae $ 1,754 $ 69 $ (26 ) $ 1,797 Other agency 239 17 — 256 Alt-A and subprime private-label securities 325 267 — 592 Mortgage revenue bonds 425 13 (4 ) 434 Other mortgage-related securities 336 14 — 350 Total $ 3,079 $ 380 $ (30 ) $ 3,429 (1) Amortized cost consists of unpaid principal balance, unamortized premiums, discounts and other cost basis adjustments, as well as net other-than-temporary impairments (“OTTI”) recognized in “ Investment gains, net ” in our condensed consolidated statements of operations and comprehensive income. (2) Represents the gross unrealized losses on securities for which we have not recognized OTTI, as well as the noncredit component of OTTI and cumulative changes in fair value of securities for which we previously recognized the credit component of OTTI in “ Accumulated other comprehensive income As of March 31, 2019 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 $ — $ — $ (19 ) $ 372 Mortgage revenue bonds (1 ) 15 (3 ) 3 Total $ (1 ) $ 15 $ (22 ) $ 375 As of December 31, 2018 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 $ — $ — $ (26 ) $ 487 Mortgage revenue bonds (1 ) 24 (3 ) 19 Total $ (1 ) $ 24 $ (29 ) $ 506 The unrealized credit loss component of AFS debt securities held by us and recognized in our condensed consolidated statements of operations and comprehensive income was $323 million and $635 million as of March 31, 2019 and December 31, 2018 , respectively. The decrease in the first three months of 2019 was primarily driven by securities for which we had a change in intent and it was more likely than not we would sell them before recovery of our amortized cost basis. The unrealized credit loss component of AFS debt securities held by us and recognized in our condensed consolidated statements of operations and comprehensive income was $729 million and $1.1 billion as of March 31, 2018 and December 31, 2017 , respectively. The decrease in the first three months of 2018 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 March 31, 2019 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 $ 1,689 $ 1,752 $ — $ — $ 14 $ 15 $ 114 $ 124 $ 1,561 $ 1,613 Other agency 225 242 — — 23 24 29 32 173 186 Alt-A and subprime private-label securities 246 452 — — — — 1 1 245 451 Mortgage revenue bonds 416 425 2 2 30 30 52 54 332 339 Other mortgage-related securities 334 343 — — — — 28 31 306 312 Total $ 2,910 $ 3,214 $ 2 $ 2 $ 67 $ 69 $ 224 $ 242 $ 2,617 $ 2,901

Financial Guarantees

Financial Guarantees	3 Months Ended
Financial Guarantees	Mar. 31, 2019
Guarantees [Abstract]
Financial Guarantees	Financial Guarantees 1 day to 34 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 off-balance sheet maximum exposure, guaranty obligation recognized in our condensed consolidated balance sheets and the potential maximum recovery from third parties through available credit enhancements and recourse related to our financial guarantees. As of March 31, 2019 December 31, 2018 Maximum Exposure Guaranty Obligation Maximum Recovery (1) Maximum Exposure Guaranty Obligation Maximum Recovery (1) (Dollars in millions) Unconsolidated Fannie Mae MBS $ 7,102 $ 29 $ 6,699 $ 7,278 $ 30 $ 6,811 Other guaranty arrangements (2) 13,626 141 2,709 13,847 130 2,711 Total $ 20,728 $ 170 $ 9,408 $ 21,125 $ 160 $ 9,522 (1) 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 13, Concentrations of Credit Risk” in our 2018 Form 10-K and “ Note 11, Concentrations of Credit Risk ” in this report. (2)

Short-Term and Long-Term Debt

Short-Term and Long-Term Debt	3 Months Ended
Short-Term and Long-Term Debt	Mar. 31, 2019
Debt Disclosure [Abstract]
Short-Term and Long-Term Debt	Short-Term and Long-Term Debt The following table displays our outstanding short-term debt (debt with an original contractual maturity of one year or less) and weighted-average interest rates of this debt. As of March 31, 2019 December 31, 2018 Outstanding Weighted- Average Interest Rate (1) Outstanding Weighted- Average Interest Rate (1) (Dollars in millions) Short-term debt of Fannie Mae $ 23,071 2.33 % $ 24,896 2.29 % (1) Includes the effects of discounts, premiums and other cost basis adjustments. Intraday Line of Credit We use a secured intraday funding line of credit provided by a large financial institution. We post collateral which, in some circumstances, the secured party has the right to repledge to third parties. As this line of credit is an uncommitted intraday loan facility, we may be unable to draw on it if and when needed. The line of credit under this facility was $15.0 billion as of March 31, 2019 and December 31, 2018 Long-term debt represents debt with an original contractual maturity of greater than one year. The following table displays our outstanding long-term debt. As of March 31, 2019 December 31, 2018 Maturities Outstanding Weighted- Average Interest Rate (1) Maturities Outstanding Weighted- Average Interest Rate (1) (Dollars in millions) Senior fixed: Benchmark notes and bonds 2019 - 2030 $ 97,710 2.46 % 2019 - 2030 $ 103,206 2.36 % Medium-term notes (2) 2019 - 2026 57,220 1.48 2019 - 2026 61,455 1.48 Other (3) 2019 - 2038 6,675 4.61 2019 - 2038 6,683 4.62 Total senior fixed 161,605 2.20 171,344 2.13 Senior floating: Medium-term notes (2) 2020 - 2020 5,574 2.47 2019 - 2020 4,174 2.36 Connecticut Avenue Securities (4) 2023 - 2031 25,064 6.13 2023 - 2031 25,641 5.97 Other (5) 2020 - 2037 376 7.85 2020 - 2037 351 10.19 Total senior floating 31,014 5.50 30,166 5.52 Subordinated debentures 2019 5,502 9.67 2019 5,617 9.64 Secured borrowings (6) 2021 - 2022 46 2.06 2021 - 2022 51 1.96 Total long-term debt of Fannie Mae (7) 198,167 2.93 207,178 2.83 Debt of consolidated trusts 2019 - 2058 3,173,772 3.06 2019 - 2058 3,159,846 3.03 Total long-term debt $ 3,371,939 3.06 % $ 3,367,024 3.02 % (1) Includes the effects of discounts, premiums and other cost basis adjustments. (2) Includes long-term debt with an original contractual maturity of greater than 1 year and up to 10 years, excluding zero-coupon debt. (3) Includes other long-term debt with an original contractual maturity of greater than 10 years and foreign exchange bonds. (4) Credit risk-sharing securities that transfer a portion of the credit risk on specified pools of single-family mortgage loans to the investors in these securities, a portion of which is reported at fair value. Represents Connecticut Avenue Securities issued prior to the implementation of our CAS REMIC structure in November 2018. See “Note 2, Consolidations and Transfers of Financial Assets” in our 2018 Form 10-K for more information about our CAS REMIC structure. (5) Consists of structured debt instruments that are reported at fair value. (6) Represents our remaining liability resulting from the transfer of financial assets from our condensed consolidated balance sheets that did not qualify as a sale under the accounting guidance for the transfer of financial instruments. (7) Includes unamortized discounts and premiums, other cost basis adjustments and fair value adjustments of $213 million and $413 million as of March 31, 2019 and December 31, 2018

Derivative Instruments

Derivative Instruments	3 Months Ended
Derivative Instruments	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	Derivative Instruments We enter into various forms of credit risk-sharing agreements that we account for as derivatives, including some of our credit risk transfer transactions and swap credit enhancements. 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. Additionally, we enter into derivative transactions that are associated with some of our other credit risk transfer transactions, whereby we manage investment risk to guarantee that certain unconsolidated VIEs have sufficient cash flows to pay their contractual obligations. We enter into forward purchase and sale commitments that lock in the future delivery of mortgage loans and mortgage-related securities at a fixed price or yield. Certain commitments to purchase mortgage loans and purchase or sell mortgage-related securities meet the criteria of a derivative. We typically settle the notional amount of our mortgage commitments that are accounted for as derivatives. We recognize all derivatives as either assets or liabilities in our condensed consolidated balance sheets at their fair value on a trade date basis. Fair value amounts, which are netted to the extent a legal right of offset exists and is enforceable by law at the counterparty level and are inclusive of the right or obligation associated with the cash collateral posted or received, are recorded in “Other assets” or “Other liabilities” in our condensed consolidated balance sheets. See “ Note 13, Fair Value ” for additional information on derivatives recorded at fair value. We present cash flows from derivatives as operating activities in our condensed consolidated statements of cash flows. Notional and Fair Value Position of our Derivatives The following table displays the notional amount and estimated fair value of our asset and liability derivative instruments. As of March 31, 2019 As of December 31, 2018 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 $ 70,599 $ 171 $ 22,538 $ (823 ) $ 71,416 $ 438 $ 21,253 $ (740 ) Receive-fixed 89,157 1,037 53,059 (541 ) 88,799 1,113 58,399 (860 ) Basis 273 129 — — 250 104 624 — Foreign currency 226 35 228 (66 ) 221 22 223 (72 ) Swaptions: Pay-fixed 5,350 46 5,625 (45 ) 10,375 191 1,000 (4 ) Receive-fixed 1,100 51 6,375 (287 ) 500 20 7,375 (338 ) Futures (1) 21,594 — — — 16,631 — — — Total gross risk management derivatives 188,299 1,469 87,825 (1,762 ) 188,192 1,888 88,874 (2,014 ) Accrued interest receivable (payable) — 395 — (462 ) — 400 — (419 ) Netting adjustment (2) — (1,781 ) — 2,126 — (2,266 ) — 2,315 Total net risk management derivatives $ 188,299 $ 83 $ 87,825 $ (98 ) $ 188,192 $ 22 $ 88,874 $ (118 ) Mortgage commitment derivatives: Mortgage commitments to purchase whole loans $ 3,901 $ 26 $ 2,153 $ (3 ) $ 4,370 $ 29 $ 57 $ — Forward contracts to purchase mortgage-related securities 53,514 403 9,649 (10 ) 40,650 349 1,045 (3 ) Forward contracts to sell mortgage-related securities 10,547 10 86,515 (653 ) 292 1 70,593 (645 ) Total mortgage commitment derivatives 67,962 439 98,317 (666 ) 45,312 379 71,695 (648 ) Credit enhancement derivatives 32,745 62 2,874 (29 ) 33,431 57 919 (11 ) Derivatives at fair value $ 289,006 $ 584 $ 189,016 $ (793 ) $ 266,935 $ 458 $ 161,488 $ (777 ) (1) Futures have no ascribable fair value because the positions are settled daily. (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 $882 million and $713 million as of March 31, 2019 and December 31, 2018 , respectively. Cash collateral received was $537 million and $664 million as of March 31, 2019 and December 31, 2018 Fair value gains (losses), net ” in our condensed consolidated statements of operations and comprehensive income. The following table displays, by type of derivative instrument, the fair value gains and losses, net on our derivatives. For the Three Months Ended March 31, 2019 2018 (Dollars in millions) Risk management derivatives: Swaps: Pay-fixed $ (1,335 ) $ 2,783 Receive-fixed 1,281 (2,387 ) Basis 24 (23 ) Foreign currency 19 16 Swaptions: Pay-fixed (177 ) 129 Receive-fixed 7 (16 ) Futures 59 8 Net accrual of periodic settlements (266 ) (215 ) Total risk management derivatives fair value gains (losses), net (388 ) 295 Mortgage commitment derivatives fair value gains (losses), net (300 ) 564 Credit enhancement derivatives fair value gains (losses), net (7 ) 4 Total derivatives fair value gains (losses), net $ (695 ) $ 863 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 12, Netting Arrangements

Segment Reporting

Segment Reporting	3 Months Ended
Segment Reporting	Mar. 31, 2019
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting We have two reportable business segments: Single-Family and Multifamily. Results of our two business segments are intended to reflect each segment as if it were a stand-alone business. The sum of the results for our two business segments equals our condensed consolidated results of operations. Segment Allocations and Results The majority of our revenues and expenses are directly associated with either our single-family or our multifamily business segment and are included in determining that segment’s operating results. Other revenues and expenses, including administrative expenses, that are not directly attributable to a particular business segment are allocated based on the size of each segment’s total book of business. The substantial majority of our gains and losses associated with our risk management derivatives are allocated to our single-family business segment. The following table displays our segment results. For the Three Months Ended March 31, 2019 2018 Single-Family Multifamily Total Single-Family Multifamily Total (Dollars in millions) Net interest income (1) $ 4,039 $ 694 $ 4,733 $ 4,561 $ 671 $ 5,232 Fee and other income (2) 106 121 227 158 162 320 Net revenues 4,145 815 4,960 4,719 833 5,552 Investment gains, net (3) 94 39 133 242 8 250 Fair value gains (losses), net (4) (887 ) 56 (831 ) 1,034 11 1,045 Administrative expenses (631 ) (113 ) (744 ) (643 ) (107 ) (750 ) Credit-related income (expense) (5) Benefit (provision) for credit losses 661 (11 ) 650 196 21 217 Foreclosed property income (expense) (143 ) 3 (140 ) (162 ) — (162 ) Total credit-related income (expense) 518 (8 ) 510 34 21 55 TCCA fees (6) (593 ) — (593 ) (557 ) — (557 ) Other expenses, net (337 ) (71 ) (408 ) (132 ) (71 ) (203 ) Income before federal income taxes 2,309 718 3,027 4,697 695 5,392 Provision for federal income taxes (484 ) (143 ) (627 ) (1,016 ) (115 ) (1,131 ) Net income $ 1,825 $ 575 $ 2,400 $ 3,681 $ 580 $ 4,261 (1) Net interest income primarily consists of guaranty fees received as compensation for assuming and managing the credit risk on loans underlying Fannie Mae MBS held by third parties for the respective business segment, and the difference between the interest income earned on the respective business segment’s mortgage assets in our retained mortgage portfolio and the interest expense associated with the debt funding those assets. Revenues from single-family guaranty fees include revenues generated by the 10 basis point increase in guaranty fees pursuant to the TCCA, the incremental revenue from which is remitted to Treasury and not retained by us. (2) Single-Family fee and other income primarily consists of compensation for engaging in structured transactions and providing other lender services, and income resulting from settlement agreements resolving certain claims relating to private-label securities we purchased or that we have guaranteed. Multifamily fee and other income consists of fees associated with multifamily business activities, including yield maintenance income. (3) Investment gains and losses primarily consists of gains and losses on the sale of mortgage assets for the respective business segment. (4) Single-Family fair value gains and losses primarily consist of fair value gains and losses on risk management and mortgage commitment derivatives, trading securities and other financial instruments associated with our single-family total book of business. Multifamily fair value gains and losses primarily consist of fair value gains and losses on MBS commitment derivatives, trading securities and other financial instruments associated with our multifamily total book of business. (5) Credit-related income or expense is based on the guaranty book of business of the respective business segment and consists of the applicable segment’s benefit or provision for credit losses and foreclosed property income or expense on loans underlying the segment’s guaranty book of business. (6)

Equity

Equity	3 Months Ended
Equity	Mar. 31, 2019
Equity [Abstract]
Equity	Equity The following table displays our accumulated other comprehensive income (“AOCI”), net of tax, by major categories. As of March 31, December 31, 2019 2018 (Dollars in millions) Net unrealized gains on AFS securities for which we have not recorded OTTI $ 67 $ 52 Net unrealized gains on AFS securities for which we have recorded OTTI 173 224 Other 43 46 Accumulated other comprehensive income $ 283 $ 322 The following table displays changes in AOCI, net of tax. For the Three Months Ended March 31, 2019 2018 AFS (1) Other Total AFS (1) Other Total (Dollars in millions) Beginning balance $ 276 $ 46 $ 322 $ 510 $ 43 $ 553 Reclassification of accumulated other comprehensive income to retained earnings resulting from the enactment of the Tax Cuts and Jobs Act (2) — — — 110 7 117 Other comprehensive income (loss) before reclassifications 8 — 8 (57 ) — (57 ) Amounts reclassified from other comprehensive loss (44 ) (3 ) (47 ) (263 ) (3 ) (266 ) Net other comprehensive loss (36 ) (3 ) (39 ) (320 ) (3 ) (323 ) Ending balance $ 240 $ 43 $ 283 $ 300 $ 47 $ 347 (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 net impairment in earnings, which are recorded in “ Investment gains, net ” in our condensed consolidated statements of operations and comprehensive income. (2) Reclassification from AOCI to retained earnings for the tax effects resulting from the enactment of tax legislation on December 22, 2017 that reduced the federal corporate income tax rate from 35% to 21%

Concentrations of Credit Risk

Concentrations of Credit Risk	3 Months Ended
Concentrations of Credit Risk	Mar. 31, 2019
Risks and Uncertainties [Abstract]
Concentrations of Credit Risk	Concentrations of Credit Risk One of the key measures by which we gauge our performance risk is the delinquency status of the mortgage loans in our guaranty book of business. 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. Single-Family credit risk characteristics For single-family loans, management monitors the serious delinquency rate, which is the percentage of single-family loans, based on the number of loans that are 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. The following tables display the delinquency status and serious delinquency rates for specified loan categories of our single-family conventional guaranty book of business. As of March 31, 2019 (1) December 31, 2018 (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) 1.15 % 0.31 % 0.67 % 1.17 % 0.32 % 0.69 % Percentage of single-family conventional loans (4) 1.32 0.35 0.74 1.37 0.38 0.76 As of March 31, 2019 (1) December 31, 2018 (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 LTV ratio: Greater than 100% * 9.35 % * 9.85 % Geographical distribution: California 19 0.34 19 0.34 Florida 6 1.03 6 1.16 New Jersey 3 1.32 4 1.38 New York 5 1.38 5 1.40 All other states 67 0.72 66 0.75 Product distribution: Alt-A 2 3.31 2 3.35 Vintages: 2004 and prior 3 2.68 3 2.69 2005-2008 4 4.50 5 4.61 2009-2019 93 0.33 92 0.34 * Represents less than 0.5% of single-family conventional business volume or book of business. (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 single-family conventional guaranty book of business as of March 31, 2019 and December 31, 2018 . (2) Consists of single-family conventional loans that were 90 days or more past due or in the foreclosure process as of March 31, 2019 and December 31, 2018 . (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) As of March 31, 2019 (1) December 31, 2018 (1) 30 Days Delinquent Seriously Delinquent (2) 30 Days Delinquent Seriously Delinquent (2) Percentage of multifamily guaranty book of business * 0.07 % 0.02 % 0.06 % As of March 31, 2019 December 31, 2018 Percentage of Multifamily Guaranty Book of Business (1) Percentage Seriously Delinquent (2)(3) Percentage of Multifamily Guaranty Book of Business (1) Percentage Seriously Delinquent (2)(3) Original LTV ratio: Greater than 80% 1 % — % 1 % — % Less than or equal to 80% 99 0.07 99 0.06 Current DSCR below 1.0 (4) 2 0.62 2 1.38 * Represents less than 0.005% of multifamily loans that were 30 days delinquent. (1) 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. (2) Consists of multifamily loans that were 60 days or more past due as of the dates indicated. (3) 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 multifamily guaranty book of business. (4) 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 Mortgage Insurers. Mortgage insurance “risk in force” refers to our maximum potential loss recovery under the applicable mortgage insurance policies in force and is generally based on the loan level insurance coverage percentage and, if applicable, any aggregate pool loss limit, as specified in the policy. The following table displays our total mortgage insurance risk in force by primary and pool insurance, as well as the total risk in force mortgage insurance coverage as a percentage of the single-family guaranty book of business. As of March 31, 2019 December 31, 2018 Risk in Force Percentage of Single-Family Guaranty Book of Business Risk in Force Percentage of Single-Family Guaranty Book of Business (Dollars in millions) Mortgage insurance risk in force: Primary mortgage insurance $ 154,823 $ 152,379 Pool mortgage insurance 400 409 Total mortgage insurance risk in force $ 155,223 5% $ 152,788 5% The table below displays our mortgage insurer counterparties that provided approximately 10% or more of the risk in force mortgage insurance coverage on mortgage loans in our single-family guaranty book of business. Percentage of Risk in Force Coverage by Mortgage Insurer As of March 31, 2019 December 31, 2018 Counterparty: (1) Arch Capital Group Ltd. 24 % 25 % Radian Guaranty, Inc. 21 21 Mortgage Guaranty Insurance Corp. 18 18 Genworth Mortgage Insurance Corp. (2) 15 15 Essent Guaranty, Inc. 12 12 Others 10 9 Total 100 % 100 % (1) Insurance coverage amounts provided for each counterparty may include coverage provided by affiliates and subsidiaries of the counterparty. (2) Genworth Financial, Inc., the ultimate parent company of Genworth Mortgage Insurance Corp., is in the process of being acquired by China Oceanwide Holdings Group Co., Ltd. We have approved the acquisition subject to specified conditions, including Genworth Financial, Inc. receiving all required and outstanding regulatory approvals. Upon acquisition, Genworth Mortgage Insurance Corp. will continue to be subject to our ongoing review of financial and operational eligibility requirements. Three of our mortgage insurer counterparties that are currently not approved to write new business are in run-off: PMI Mortgage Insurance Co. (“PMI”), Triad Guaranty Insurance Corporation (“Triad”) and Republic Mortgage Insurance Company (”RMIC”). 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 $4.4 billion , or 3% , of our risk in force mortgage insurance coverage of our single-family guaranty book of business as of March 31, 2019 . PMI and Triad have been paying only a portion of policyholder claims and deferring the remaining portion. PMI is currently paying 74.5% of claims under its mortgage insurance policies in cash and is deferring the remaining 25.5% , 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 its previously outstanding deferred payment obligations as well as interest on those obligations; however, RMIC remains in run-off. We have counterparty credit risk relating to the potential insolvency of, or non-performance by, mortgage insurers that insure single-family loans we purchase or guarantee. There is risk that these counterparties may fail to fulfill their obligations to pay our claims under insurance policies. If we determine that it is probable that we will not collect all of our claims from one or more of our mortgage insurer counterparties, it could increase our loss reserves, which could adversely affect our results of operations, liquidity, financial condition and net worth. When we estimate the credit losses that are inherent in our mortgage loans and under the terms of our guaranty obligations we also consider the recoveries that we will receive on primary mortgage insurance, as mortgage insurance recoveries would reduce the severity of the loss associated with defaulted loans. We evaluate the financial condition of our mortgage insurer counterparties and adjust the contractually due recovery amounts to ensure that only probable losses as of the balance sheet date are included in our loss reserve estimate. As a result, if our assessment of one or more of our mortgage insurer counterparties’ ability to fulfill their respective obligations to us worsens, it could increase our loss reserves. As of March 31, 2019 and December 31, 2018 , our estimated benefit from mortgage insurance reduced our loss reserves by $665 million and $691 million , respectively. As of March 31, 2019 and December 31, 2018 , we had outstanding receivables of $699 million and $745 million , respectively, recorded in “Other assets” in our condensed consolidated balance sheets related to amounts claimed on insured, defaulted loans excluding government-insured loans. As of March 31, 2019 and December 31, 2018 , we assessed these outstanding receivables for collectibility, and established a valuation allowance of $544 million and $564 million , respectively, which reduces our claim receivable to the amount considered probable of collection. Mortgage Servicers and Sellers. 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 servicers and sellers 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. Our representation and warranty framework does not 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. The table below displays the percentage of our single-family guaranty book of business serviced by our top five depository single-family mortgage servicers and top five non-depository single-family mortgage servicers, and identifies one servicer that serviced more than 10% of our single-family guaranty book of business based on unpaid principal balance. Percentage of Single-Family Guaranty Book of Business As of March 31, 2019 December 31, 2018 Wells Fargo Bank, N.A. (together with its affiliates) 18 % 18 % Remaining top five depository servicers 15 16 Top five non-depository servicers 25 22 Total 58 % 56 % There was an increase in the portion of our single-family guaranty book serviced by our top five non-depository servicers, particularly for our delinquent single-family loans. Compared with depository financial institutions, these institutions pose additional risks to us because they may not have the same financial strength or operational capacity, or be subject to the same level of regulatory oversight, as our largest mortgage servicer counterparties, which are mostly depository institutions. The table below displays the percentage of our multifamily guaranty book of business serviced by our top five multifamily mortgage servicers, and identifies two servicers that serviced 10% or more of our multifamily guaranty book of business based on unpaid principal balance. Percentage of Multifamily Guaranty Book of Business As of March 31, 2019 December 31, 2018 Wells Fargo Bank, N.A. (together with its affiliates) 14 % 14 % Walker & Dunlop, LLC 12 12 Remaining top five servicers 22 22 Total 48 % 48 % If a significant mortgage servicer or seller counterparty, or a number of mortgage servicers or sellers, fails to meet their obligations to us, it could adversely affect our results of operations and financial condition. We mitigate these risks in several ways, including: • establishing minimum standards and financial requirements for our servicers; • monitoring financial and portfolio performance as compared with peers and internal benchmarks; and • for our largest mortgage servicers, conducting periodic on-site and financial reviews to confirm compliance with servicing guidelines and servicing performance expectations. We may take one or more of the following actions to mitigate our credit exposure to mortgage servicers that present a higher risk: • require a guaranty of obligations by higher-rated entities; • transfer exposure to third parties; • require collateral; • establish more stringent financial requirements; • work on-site with underperforming major servicers to improve operational processes; and • suspend or terminate the selling and servicing relationship if deemed necessary. Derivative Counterparties. For information on credit risk associated with our derivative transactions and repurchase agreements see “ Note 8, Derivative Instruments ” and “ Note 12, Netting Arrangements

Netting Arrangements

Netting Arrangements	3 Months Ended
Netting Arrangements	Mar. 31, 2019
Offsetting [Abstract]
Netting Arrangements	Netting Arrangements We use master netting arrangements, which allow us to offset certain financial instruments and collateral with the same counterparty, to minimize counterparty credit exposure. The tables below display information related to derivatives, securities purchased under agreements to resell or similar arrangements, and securities sold under agreements to repurchase or similar arrangements, which are subject to an enforceable master netting arrangement or similar agreement that are either offset or not offset in our condensed consolidated balance sheets. As of March 31, 2019 Gross Amount Offset (1) Net Amount Presented in our Condensed Consolidated Balance Sheets Amounts Not Offset in our Condensed Consolidated Balance Sheets Gross Amount Financial Instruments (2) Collateral (3) Net Amount (Dollars in millions) Assets: OTC risk management derivatives $ 1,864 $ (1,801 ) $ 63 $ — $ — $ 63 Cleared risk management derivatives — 20 20 — — 20 Mortgage commitment derivatives 439 — 439 (223 ) (14 ) 202 Total derivative assets 2,303 (1,781 ) 522 (4) (223 ) (14 ) 285 Securities purchased under agreements to resell or similar arrangements (5) 39,850 — 39,850 — (39,850 ) — Total assets $ 42,153 $ (1,781 ) $ 40,372 $ (223 ) $ (39,864 ) $ 285 Liabilities: OTC risk management derivatives $ (2,224 ) $ 2,143 $ (81 ) $ — $ — $ (81 ) Cleared risk management derivatives — (17 ) (17 ) — 10 (7 ) Mortgage commitment derivatives (666 ) — (666 ) 223 416 (27 ) Total derivative liabilities (2,890 ) 2,126 (764 ) (4) 223 426 (115 ) Total liabilities $ (2,890 ) $ 2,126 $ (764 ) $ 223 $ 426 $ (115 ) As of December 31, 2018 Gross Amount Offset (1) Net Amount Presented in our Condensed Consolidated Balance Sheets Amounts Not Offset in our Condensed Consolidated Balance Sheets Gross Amount Financial Instruments (2) Collateral (3) Net Amount (Dollars in millions) Assets: OTC risk management derivatives $ 2,288 $ (2,273 ) $ 15 $ — $ — $ 15 Cleared risk management derivatives — 7 7 — — 7 Mortgage commitment derivatives 379 — 379 (153 ) (7 ) 219 Total derivative assets 2,667 (2,266 ) 401 (4) (153 ) (7 ) 241 Securities purchased under agreements to resell or similar arrangements (5) 48,288 — 48,288 — (48,288 ) — Total assets $ 50,955 $ (2,266 ) $ 48,689 $ (153 ) $ (48,295 ) $ 241 Liabilities: OTC risk management derivatives $ (2,433 ) $ 2,342 $ (91 ) $ — $ — $ (91 ) Cleared risk management derivatives — (27 ) (27 ) — 23 (4 ) Mortgage commitment derivatives (648 ) — (648 ) 153 466 (29 ) Total derivative liabilities (3,081 ) 2,315 (766 ) (4) 153 489 (124 ) Total liabilities $ (3,081 ) $ 2,315 $ (766 ) $ 153 $ 489 $ (124 ) (1) Represents the effect of the right to offset under legally enforceable master netting arrangements to settle with the same counterparty on a net basis, including cash collateral posted and received and accrued interest. (2) Mortgage commitment derivative amounts reflect where we have recognized both an asset and a liability with the same counterparty under an enforceable master netting arrangement but we have not elected to offset the related amounts in our condensed consolidated balance sheets. (3) Represents collateral received that has not been recognized and is not offset in our condensed consolidated balance sheets as well as collateral posted which has been recognized but not offset in our condensed consolidated balance sheets. The fair value of non-cash collateral we pledged was $1.8 billion and $1.9 billion as of March 31, 2019 and December 31, 2018 , respectively, which the counterparty was permitted to sell or repledge. The fair value of non-cash collateral received was $39.9 billion and $48.4 billion , of which $33.9 billion and $45.7 billion could be sold or repledged as of March 31, 2019 and December 31, 2018 , respectively. None of the underlying collateral was sold or repledged as of March 31, 2019 or December 31, 2018 . (4) Excludes derivative assets of $62 million and $57 million as of March 31, 2019 and December 31, 2018 , respectively, and derivative liabilities of $29 million and $11 million recognized in our condensed consolidated balance sheets as of March 31, 2019 and December 31, 2018 , respectively, that are not subject to enforceable master netting arrangements. (5) Includes $17.6 billion and $15.4 billion in securities purchased under agreements to resell classified as “Cash and cash equivalents” in our condensed consolidated balance sheets as of March 31, 2019 and December 31, 2018 , respectively. Derivative instruments are recorded at fair value and securities purchased under agreements to resell or similar arrangements are recorded at amortized cost in our condensed consolidated balance sheets. For how we determine our rights to offset the assets and liabilities presented above with the same counterparty, including collateral posted or received, see “ Note 14, Netting Arrangements ” in our 2018

Fair Value

Fair Value	3 Months Ended
Fair Value	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value	Fair Value Fair Value Measurement Fair value measurement guidance defines fair value, establishes a framework for measuring fair value, and sets forth disclosures around fair value measurements. This guidance applies whenever other accounting guidance requires or permits assets or liabilities to be measured at fair value. The guidance establishes a three-level fair value hierarchy that prioritizes the inputs into the valuation techniques used to measure fair value. The fair value hierarchy gives the highest priority, Level 1, to measurements based on unadjusted quoted prices in active markets for identical assets or liabilities. The next highest priority, Level 2, is given to measurements of assets and liabilities based on limited observable inputs or observable inputs for similar assets and liabilities. The lowest priority, Level 3, is given to measurements based on unobservable inputs. Recurring Changes in Fair Value The following tables display our assets and liabilities measured in our condensed consolidated balance sheets at fair value on a recurring basis subsequent to initial recognition, including instruments for which we have elected the fair value option. Fair Value Measurements as of March 31, 2019 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 $ — $ 1,516 $ 67 $ — $ 1,583 Other agency — 3,158 — — 3,158 Private-label and other mortgage securities — 1,054 — — 1,054 Non-mortgage-related securities: U.S. Treasury securities 35,020 — — — 35,020 Other securities — 84 — — 84 Total trading securities 35,020 5,812 67 — 40,899 Available-for-sale securities: Mortgage-related securities: Fannie Mae — 1,553 199 — 1,752 Other agency — 242 — — 242 Alt-A and subprime private-label securities — 429 23 — 452 Mortgage revenue bonds — — 425 — 425 Other — 6 337 — 343 Total available-for-sale securities — 2,230 984 — 3,214 Mortgage loans — 7,818 934 — 8,752 Other assets: Risk management derivatives: Swaps — 1,633 134 — 1,767 Swaptions — 97 — — 97 Netting adjustment — — — (1,781 ) (1,781 ) Mortgage commitment derivatives — 399 40 — 439 Credit enhancement derivatives — — 62 — 62 Total other assets — 2,129 236 (1,781 ) 584 Total assets at fair value $ 35,020 $ 17,989 $ 2,221 $ (1,781 ) $ 53,449 Fair Value Measurements as of March 31, 2019 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 $ — $ 6,306 $ 376 $ — $ 6,682 Total of Fannie Mae — 6,306 376 — 6,682 Of consolidated trusts — 22,826 224 — 23,050 Total long-term debt — 29,132 600 — 29,732 Other liabilities: Risk management derivatives: Swaps — 1,891 1 — 1,892 Swaptions — 332 — — 332 Netting adjustment — — — (2,126 ) (2,126 ) Mortgage commitment derivatives — 663 3 — 666 Credit enhancement derivatives — — 29 — 29 Total other liabilities — 2,886 33 (2,126 ) 793 Total liabilities at fair value $ — $ 32,018 $ 633 $ (2,126 ) $ 30,525 Fair Value Measurements as of December 31, 2018 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: Cash equivalents (2) $ 748 $ — $ — $ — $ 748 Trading securities: Mortgage-related securities: Fannie Mae — 1,435 32 — 1,467 Other agency — 3,503 — — 3,503 Private-label and other mortgage securities — 1,305 1 — 1,306 Non-mortgage-related securities: U.S. Treasury securities 35,502 — — — 35,502 Other Securities — 89 — — 89 Total trading securities 35,502 6,332 33 — 41,867 Available-for-sale securities: Mortgage-related securities: Fannie Mae — 1,645 152 — 1,797 Other agency — 256 — — 256 Alt-A and subprime private-label securities — 568 24 — 592 Mortgage revenue bonds — — 434 — 434 Other — 8 342 — 350 Total available-for-sale securities — 2,477 952 — 3,429 Mortgage loans — 7,985 937 — 8,922 Other assets: Risk management derivatives: Swaps — 1,962 115 — 2,077 Swaptions — 211 — — 211 Netting adjustment — — — (2,266 ) (2,266 ) Mortgage commitment derivatives — 342 37 — 379 Credit enhancement derivatives — — 57 — 57 Total other assets — 2,515 209 (2,266 ) 458 Total assets at fair value $ 36,250 $ 19,309 $ 2,131 $ (2,266 ) $ 55,424 Fair Value Measurements as of December 31, 2018 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 $ — $ 6,475 $ 351 $ — $ 6,826 Total of Fannie Mae — 6,475 351 — 6,826 Of consolidated trusts — 23,552 201 — 23,753 Total long-term debt — 30,027 552 — 30,579 Other liabilities: Risk management derivatives: Swaps — 2,089 2 — 2,091 Swaptions — 342 — — 342 Netting adjustment — — — (2,315 ) (2,315 ) Mortgage commitment derivatives — 646 2 — 648 Credit enhancement derivatives — — 11 — 11 Total other liabilities — 3,077 15 (2,315 ) 777 Total liabilities at fair value $ — $ 33,104 $ 567 $ (2,315 ) $ 31,356 (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. (2) Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Three Months Ended March 31, 2019 Total Gains (Losses) (Realized/Unrealized) Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of March 31, 2019 (5)(6) Net Unrealized Gains (Losses) Included in OCI Related to Assets and Liabilities Still Held as of March 31, 2019 (1) Balance, December 31, 2018 Included in Net Income Included in Total OCI Gain/(Loss) (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 Transfers into Level 3 Balance, March 31, 2019 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 32 $ 2 $ — $ — $ — $ — $ — $ — $ 33 $ 67 $ 2 $ — Private-label and other mortgage securities 1 — — — — — (1 ) — — — — — Total trading securities $ 33 $ 2 (6)(7) $ — $ — $ — $ — $ (1 ) $ — $ 33 $ 67 $ 2 $ — Available-for-sale securities: Mortgage-related: Fannie Mae $ 152 $ — $ 4 $ — $ — $ — $ — $ (41 ) $ 84 $ 199 $ — $ 2 Alt-A and subprime private-label securities 24 — — — — — (1 ) — — 23 — — Mortgage revenue bonds 434 — — — — — (9 ) — — 425 — — Other 342 7 (5 ) — — — (8 ) — 1 337 — (4 ) Total available-for-sale securities $ 952 $ 7 (7)(8) $ (1 ) $ — $ — $ — $ (18 ) $ (41 ) $ 85 $ 984 $ — $ (2 ) Mortgage loans $ 937 $ 14 (6)(7) $ — $ — $ — $ — $ (34 ) $ (28 ) $ 45 $ 934 $ 11 $ — Net derivatives 194 98 (6) — — — — (89 ) — — 203 44 — Long-term debt: Of Fannie Mae: Senior floating (351 ) (25 ) — — — — — — — (376 ) (25 ) — Of consolidated trusts (201 ) (3 ) — — — — 5 49 (74 ) (224 ) (1 ) — Total long-term debt $ (552 ) $ (28 ) (6) $ — $ — $ — $ — $ 5 $ 49 $ (74 ) $ (600 ) $ (26 ) $ — Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Three Months Ended March 31, 2018 Total Gains (Losses) (Realized/Unrealized) Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of March 31, 2018 (5)(6) Net Unrealized Gains (Losses) Included in OCI Related to Assets and Liabilities Still Held as of March 31, 2018 (1) Balance, December 31, 2017 Included in Net Income Included in Total OCI (Loss) (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 (4) Transfers into Level 3 Balance, March 31, 2018 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 971 $ 171 $ — $ 1 $ (1,060 ) $ — $ — $ — $ — $ 83 $ 1 $ — Other agency 35 (1 ) — — — — (1 ) (33 ) — — — — Private-label and other mortgage securities 195 (85 ) — — — — (5 ) (104 ) — 1 — — Total trading securities $ 1,201 $ 85 (6)(7) $ — $ 1 $ (1,060 ) $ — $ (6 ) $ (137 ) $ — $ 84 $ 1 $ — Available-for-sale securities: Mortgage-related: Fannie Mae $ 208 $ — $ (4 ) $ — $ — $ — $ (2 ) $ — $ — $ 202 $ — $ (3 ) Alt-A and subprime private-label securities 77 — (45 ) — — — (1 ) (4 ) — 27 — 1 Mortgage revenue bonds 671 11 (13 ) — (11 ) — (119 ) — — 539 — (8 ) Other 357 7 (2 ) — — — (11 ) — — 351 — — Total available-for-sale securities $ 1,313 $ 18 (7)(8) $ (64 ) $ — $ (11 ) $ — $ (133 ) $ (4 ) $ — $ 1,119 $ — $ (10 ) Mortgage loans $ 1,116 $ 17 (6)(7) $ — $ — $ — $ — $ (48 ) $ (36 ) $ 53 $ 1,102 $ 11 $ — Net derivatives 134 (58 ) (6) — — — — 4 53 — 133 (22 ) — Long-term debt: Of Fannie Mae: Senior floating (376 ) 19 — — — — — — — (357 ) 19 — Of consolidated trusts (582 ) 3 — — — 1 10 154 (48 ) (462 ) 1 — Total long-term debt $ (958 ) $ 22 (6) $ — $ — $ — $ 1 $ 10 $ 154 $ (48 ) $ (819 ) $ 20 $ — (1) Gains (losses) included in other comprehensive loss are included in “Changes in unrealized gains on AFS securities, net of reclassification adjustments and taxes” in our condensed consolidated statements of operations and comprehensive income. (2) Purchases and sales include activity related to the consolidation and deconsolidation of assets of securitization trusts. For the three months ended March 31, 2018, includes the dissolution of a Fannie Mae-wrapped private-label securities trust. (3) Issues and settlements include activity related to the consolidation and deconsolidation of liabilities of securitization trusts. (4) Transfers out of Level 3 during the first quarter of 2018 consisted primarily of mortgage loans of consolidated trusts for which unobservable inputs used in valuations became less significant. Transfers out of Level 3 also included private-label mortgage-related securities backed by Alt-A loans and subprime loans. Prices for these securities were available from multiple third-party vendors and demonstrated an increased and sustained level of observability over time. (5) Amount represents temporary changes in fair value. Amortization, accretion and OTTI are not considered unrealized and are not included in this amount. (6) Gains (losses) are included in “ Fair value gains (losses), net ” in our condensed consolidated statements of operations and comprehensive income. (7) Gains (losses) are included in “ Net interest income ” in our condensed consolidated statements of operations and comprehensive income. (8) Gains (losses) are included in “ Investment gains, net Fair Value Measurements as of March 31, 2019 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Recurring fair value measurements: Trading securities: Mortgage-related securities: Agency (2) $ 67 Various Available-for-sale securities: Mortgage-related securities: Agency (2) $ 105 Consensus 94 Various Total agency 199 Alt-A and subprime private-label securities 23 Various Mortgage revenue bonds 304 Single Vendor Spreads (bps) 16.0 - 265.2 71.2 121 Various Total mortgage revenue bonds 425 Other 289 Discounted Cash Flow Default Rate (%) 4.1 4.1 Prepayment Speed (%) 4.6 4.6 Severity (%) 95.0 95.0 Spreads (bps) 68.2 - 290.0 289.4 48 Various Total other 337 Total available-for-sale securities $ 984 Net derivatives $ 132 Dealer Mark 71 Various Total net derivatives $ 203 Fair Value Measurements as of December 31, 2018 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1)(2) (Dollars in millions) Recurring fair value measurements: Trading securities: Mortgage-related securities: Agency (2) $ 32 Various Private-label securities and other mortgage securities 1 Various Total trading securities $ 33 Available-for-sale securities: Mortgage-related securities: Agency (2) $ 152 Various Alt-A and subprime private-label securities 24 Various Mortgage revenue bonds 349 Single Vendor Spreads(bps) (0.5 ) - 332.8 59.0 85 Various Total mortgage revenue bonds 434 Other 294 Discounted Cash Flow Default Rate(%) 4.7 4.7 Prepayment Speed(%) 8.2 8.2 Severity(%) 70.0 70.0 Spreads(bps) 75.4 - 390.0 389.1 48 Various Total other 342 Total available-for-sale securities $ 952 Net derivatives $ 113 Dealers Mark 81 Various Total net derivatives $ 194 (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) Unobservable inputs were weighted by the relative fair value of the instruments. In our condensed consolidated balance sheets certain assets and liabilities are measured at fair value on a nonrecurring basis; that is, the instruments are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (for example, when we evaluate loans for impairment). We had no Level 1 assets or liabilities held as of March 31, 2019 or December 31, 2018 that were measured at fair value on a nonrecurring basis. We held $946 million and $91 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 March 31, 2019 and December 31, 2018 , respectively. The following table displays valuation techniques for our Level 3 assets measured at fair value on a nonrecurring basis. The significant unobservable inputs related to these techniques primarily relate to collateral dependent valuations. The related ranges and weighted averages are not meaningful when aggregated as they vary significantly from property to property. Fair Value Measurements as of Valuation Techniques March 31, 2019 December 31, 2018 Nonrecurring fair value measurements: Mortgage loans held for sale, at lower of cost or fair value Consensus $ 1,487 $ 631 Single Vendor 828 1,119 Various 1 — Total mortgage loans held for sale, at lower of cost or fair value 2,316 1,750 Single-family mortgage loans held for investment, at amortized cost Internal Model 609 818 Multifamily mortgage loans held for investment, at amortized cost Asset Manager Estimate 153 102 Various 10 40 Total multifamily mortgage loans held for investment, at amortized cost 163 142 Acquired property, net: (1) Single-family Accepted Offers 153 151 Appraisals 346 419 Walk Forwards 158 181 Internal Model 147 219 Various 37 41 Total single-family 841 1,011 Multifamily Various 5 50 Other assets Various — — Total nonrecurring assets at fair value $ 3,934 $ 3,771 (1) The most commonly used techniques in our valuation of acquired property are proprietary home price model and third-party valuations (both current and walk forward). Based on the number of properties measured as of March 31, 2019 , these methodologies comprised approximately 78% of our valuations, while accepted offers comprised approximately 18% of our valuations. Based on the number of properties measured as of December 31, 2018 , these methodologies comprised approximately 82% of our valuations, while accepted offers comprised approximately 15% of our valuations. We use valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. See “ Note 15, Fair Value ” in our 2018 Form 10-K for information on the valuation control processes and the valuation techniques we use for fair value measurement and disclosure as well as our basis for classifying these measurements as Level 1, Level 2 or Level 3 of the valuation hierarchy in more specific situations. We made no material changes to the valuation control processes or the valuation techniques for the three months ended March 31, 2019 The following table displays the carrying value and estimated fair value of our financial instruments. The fair value of financial instruments we disclose includes commitments to purchase multifamily and single-family mortgage loans that we do not record in our condensed consolidated balance sheets. The fair values of these commitments are included as “Mortgage loans held for investment, net of allowance for loan losses.” The disclosure excludes all non-financial instruments; therefore, the fair value of our financial assets and liabilities does not represent the underlying fair value of our total consolidated assets and liabilities. As of March 31, 2019 Carrying Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Netting Adjustment Estimated (Dollars in millions) Financial assets: Cash and cash equivalents and restricted cash $ 52,241 $ 34,641 $ 17,600 $ — $ — $ 52,241 Federal funds sold and securities purchased under agreements to resell or similar arrangements 22,250 — 22,250 — — 22,250 Trading securities 40,899 35,020 5,812 67 — 40,899 Available-for-sale securities 3,214 — 2,230 984 — 3,214 Mortgage loans held for sale 10,066 — 2,729 7,931 — 10,660 Mortgage loans held for investment, net of allowance for loan losses 3,249,699 — 2,982,238 275,207 — 3,257,445 Advances to lenders 4,246 — 4,244 2 — 4,246 Derivative assets at fair value 584 — 2,129 236 (1,781 ) 584 Guaranty assets and buy-ups 159 — — 370 — 370 Total financial assets $ 3,383,358 $ 69,661 $ 3,039,232 $ 284,797 $ (1,781 ) $ 3,391,909 Financial liabilities: Short-term debt: Of Fannie Mae $ 23,071 $ — $ 23,078 $ — $ — $ 23,078 Long-term debt: Of Fannie Mae 198,167 — 204,060 813 — 204,873 Of consolidated trusts 3,173,772 — 3,118,819 43,205 — 3,162,024 Derivative liabilities at fair value 793 — 2,886 33 (2,126 ) 793 Guaranty obligations 170 — — 107 — 107 Total financial liabilities $ 3,395,973 $ — $ 3,348,843 $ 44,158 $ (2,126 ) $ 3,390,875 As of December 31, 2018 Carrying Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Netting Adjustment Estimated (Dollars in millions) Financial assets: Cash and cash equivalents and restricted cash $ 49,423 $ 34,073 $ 15,350 $ — $ — $ 49,423 Federal funds sold and securities purchased under agreements to resell or similar arrangements 32,938 — 32,938 — — 32,938 Trading securities 41,867 35,502 6,332 33 — 41,867 Available-for-sale securities 3,429 — 2,477 952 — 3,429 Mortgage loans held for sale 7,701 — 238 7,856 — 8,094 Mortgage loans held for investment, net of allowance for loan losses 3,241,694 — 2,990,104 216,404 — 3,206,508 Advances to lenders 3,356 — 3,354 2 — 3,356 Derivative assets at fair value 458 — 2,515 209 (2,266 ) 458 Guaranty assets and buy-ups 147 — — 356 — 356 Total financial assets $ 3,381,013 $ 69,575 $ 3,053,308 $ 225,812 $ (2,266 ) $ 3,346,429 Financial liabilities: Short-term debt: Of Fannie Mae $ 24,896 $ — $ 24,901 $ — $ — $ 24,901 Long-term debt: Of Fannie Mae 207,178 — 211,403 771 — 212,174 Of consolidated trusts 3,159,846 — 3,064,239 39,043 — 3,103,282 Derivative liabilities at fair value 777 — 3,077 15 (2,315 ) 777 Guaranty obligations 160 — — 121 — 121 Total financial liabilities $ 3,392,857 $ — $ 3,303,620 $ 39,950 $ (2,315 ) $ 3,341,255 For a detailed description and classification of our financial instruments, see “ Note 15, Fair Value ” in our 2018 We elected the fair value option for loans and debt that contain embedded derivatives that would otherwise require bifurcation. Additionally, we elected the fair value option for our credit risk-sharing securities accounted for as debt of Fannie Mae issued under our CAS series prior to January 1, 2016. Under the fair value option, we elected to carry these instruments at fair value instead of bifurcating the embedded derivative from such instruments. Interest income for the mortgage loans is recorded in “Interest income—Mortgage loans” and interest expense for the debt instruments is recorded in “Interest expense—Long-term debt” in our condensed consolidated statements of operations and comprehensive income. The following table displays the fair value and unpaid principal balance of the financial instruments for which we have made fair value elections. As of March 31, 2019 December 31, 2018 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 $ 8,752 $ 6,682 $ 23,050 $ 8,922 $ 6,826 $ 23,753 Unpaid principal balance 8,578 6,050 21,216 8,832 6,241 22,080 (1) Includes nonaccrual loans with a fair value of $145 million and $161 million as of March 31, 2019 and December 31, 2018 , respectively. The difference between unpaid principal balance and the fair value of these nonaccrual loans as of March 31, 2019 and December 31, 2018 was $16 million and $19 million , respectively. Includes loans that are 90 days or more past due with a fair value of $95 million and $102 million as of March 31, 2019 and December 31, 2018 , respectively. The difference between unpaid principal balance and the fair value of these 90 or more days past due loans as of March 31, 2019 and December 31, 2018 was $12 million and $14 million , respectively. Changes in Fair Value under the Fair Value Option Election We recorded gains of $113 million and losses of $149 million for the three months ended March 31, 2019 and March 31, 2018 , respectively, from changes in the fair value of loans recorded at fair value in “Fair value gains (losses), net” in our condensed consolidated statements of operations and comprehensive income. We recorded losses of $330 million and gains of $254 million for the three months ended March 31, 2019 and March 31, 2018

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
Commitments and Contingencies	Mar. 31, 2019
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. 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. 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 establish an accrual only for matters when a loss is probable and we can reasonably estimate the amount of such loss. 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 consolidated putative class action (“ In re Fannie Mae/Freddie Mac Senior Preferred Stock Purchase Agreement Class Action Litigations ”) and three non-class action lawsuits filed by Fannie Mae and Freddie Mac shareholders against us, FHFA as our conservator, and Freddie Mac are pending in the U.S. District Court for the District of Columbia. The lawsuits challenge the August 2012 amendment to each company’s senior preferred stock purchase agreement with Treasury. In the consolidated class action and two of the non-class action suits, Arrowood Indemnity Company v. Fannie Mae and Fairholme Funds v. FHFA, plaintiffs filed amended complaints on November 1, 2017 alleging that the net worth sweep dividend provisions of the senior preferred stock that were implemented pursuant to the August 2012 amendments nullified certain of the shareholders’ rights, particularly the right to receive dividends. Plaintiffs seek unspecified damages, equitable and injunctive relief, and costs and expenses, including attorneys’ fees. Plaintiffs in the class action 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. On September 28, 2018, the court dismissed all of the plaintiffs’ claims except for their claims for breach of an implied covenant of good faith and fair dealing. On October 15, 2018, defendants filed a motion for partial reconsideration. On May 21, 2018, a pro se plaintiff in a third non-class action case, Angel v. Federal Home Loan Mortgage Corporation, filed a complaint for declaratory relief and compensatory damages against Fannie Mae (including certain members of its Board of Directors), Freddie Mac (including certain members of its Board of Directors) and FHFA, as conservator. Plaintiff in that case asserts claims for breach of contract, breach of implied covenants of good faith and fair dealing, and aiding and abetting the federal government in avoiding an alleged implicit guarantee of dividend payments. On March 6, 2019, the court granted defendants’ motion to dismiss and on March 18, 2019, plaintiff moved to alter or amend the judgment and to file an amended complaint.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation [Policy Text Block]	Basis of Presentation The accompanying unaudited interim condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) for interim financial information and with the SEC’s instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and note disclosures required by GAAP for complete consolidated financial statements. In the opinion of management, all adjustments of a normal recurring nature considered necessary for a fair presentation have been included. The accompanying condensed consolidated financial statements include our accounts as well as the accounts of other entities in which we have a controlling financial interest. All intercompany accounts and transactions have been eliminated. To conform to our current period presentation, we have reclassified certain amounts reported in our prior period condensed consolidated financial statements. Results for the three months ended March 31, 2019 may not necessarily be indicative of the results for the year ending December 31, 2019
Use of Estimates, Policy [Policy Text Block]	Use of EstimatesPreparing condensed consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that affect our reported amounts of assets and liabilities, disclosure of contingent assets and liabilities as of the dates of our condensed consolidated financial statements, as well as our reported amounts of revenues and expenses during the reporting periods. Management has made significant estimates in a variety of areas including, but not limited to, the allowance for loan losses. Actual results could be different from these estimates.
Earnings Per Share, Policy [Policy Text Block]	Earnings per share (“EPS”) is presented for basic and diluted EPS. We compute basic EPS by dividing net income attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period. However, as a result of our conservatorship status and the terms of the senior preferred stock, no amounts would be available to distribute as dividends to common or preferred stockholders (other than to Treasury as the holder of the senior preferred stock). Weighted average common shares includes 4.6 billion shares for the periods ended March 31, 2019 and 2018 that would be issued upon the full exercise of the warrant issued to Treasury from the date the warrant was issued through March 31, 2019 and 2018 . The calculation of diluted EPS includes all the components of basic earnings per share, plus the dilutive effect of common stock equivalents such as convertible securities and stock options. Weighted average shares outstanding is increased to include the number of additional common shares that would have been outstanding if the dilutive potential common shares had been issued. For the three months ended March 31, 2019 and 2018 , our diluted EPS weighted average shares outstanding includes shares of common stock that would be issuable upon the conversion of 131 million
New Accounting Pronouncements, Policy [Policy Text Block]	New Accounting Guidance The following table updates information about our significant accounting policies that have recently been adopted or are yet to be adopted from the information included in “Note 1, Summary of Significant Accounting Policies” in our 2018 Form 10-K. Standard Description Effective Date Impact on Consolidated Financial Statements ASU 2016-02, Leases (Topic 842) The amendment addresses the accounting for lease arrangements. January 1, 2019 We adopted this standard on January 1, 2019. The adoption of this guidance did not have a material impact on our consolidated financial statements. ASU 2017-12 - Derivatives and Hedging (Topic 815) The amendments in this standard made targeted improvements to accounting for hedging activities. The standard changes the recognition and presentation requirements of hedge accounting and provides new alternatives for measuring and accounting for certain aspects of hedging activities. January 1, 2019 This guidance became effective this quarter. Hedge accounting is elective and, while we do not currently have a hedge accounting program, we are developing capabilities to implement hedge accounting to reduce interest rate volatility in our consolidated statements of operations and comprehensive income. ASU 2016-13 , Financial Instruments—Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments (“CECL”) The amendments in this standard replace the incurred loss impairment methodology in current GAAP with a methodology that reflects lifetime expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. January 1, 2020 CECL will become effective for our fiscal year beginning January 1, 2020. We will recognize the impact of the new guidance through a cumulative effect adjustment to retained earnings as of the beginning of the year of adoption. We are continuing to update our allowance models and accounting systems that will be used to estimate credit losses and record accounting impacts under CECL, and we are in the process of validating their results. All updates to our allowance models are subject to our model oversight and review governance process. We expect model and system testing to continue in 2019, followed by full integrated testing across all impacted systems and processes. Implementation of this guidance is being managed in accordance with our change management governance standards, which are designed to ensure compliance with GAAP as well as operational readiness at adoption. We provide updates to senior management and the Audit Committee regarding the status of our implementation plan, results of initial modeled impacts and any identified key risks. We are continuing to evaluate the impact of this guidance on our consolidated financial statements. The adoption of this guidance likely will increase our allowance for credit losses and decrease, perhaps substantially, our retained earnings. We expect the greater impact of the guidance to relate to our accounting for credit losses for loans that are not individually impaired. We do not expect a material impact from the valuation allowance associated with our available for sale securities. However, the impact at adoption will be influenced by the composition and quality of our total book of business at the adoption date, as well as economic conditions and forecasts at that time.

Consolidations and Transfers _2

Consolidations and Transfers of Financial Assets (Policies)	3 Months Ended
Consolidations and Transfers of Financial Assets (Policies)	Mar. 31, 2019
Consolidations and Transfers of Financial Assets [Abstract]
Consolidations, Policy [Policy Text Block]	We have interests in various entities that are considered to be variable interest entities (“VIEs”). The primary types of entities are securitization trusts, limited partnerships and special purpose vehicles (“SPVs”). These interests include investments in securities issued by VIEs, such as Fannie Mae mortgage-backed securities (“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.We do not consolidate VIEs when we are not deemed to be the primary beneficiary. Our unconsolidated VIEs include securitization trusts, limited partnerships, and certain SPVs designed to transfer credit risk.
Transfers and Servicing of Financial Assets, Policy [Policy Text Block]	Transfers of Financial AssetsWe issue Fannie Mae MBS through portfolio securitization transactions by transferring pools of mortgage loans or mortgage-related securities to one or more trusts or special purpose entities. We are considered to be the transferor when we transfer assets from our own retained mortgage portfolio in a portfolio securitization transaction.

Mortgage Loans (Policies)

Mortgage Loans (Policies)	3 Months Ended
Mortgage Loans (Policies)	Mar. 31, 2019
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Abstract]
Finance, Loan and Lease Receivables, Held-for-investment, Policy [Policy Text Block]	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 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.
Finance, Loan and Lease Receivables, Held-for-sale, Policy [Policy Text Block]	We report the carrying value of HFS loans at the lower of cost or fair value and record valuation changes in “ Investment gains, net
Nonaccrual Loans [Policy Text Block]	We discontinue accruing interest on loans when we believe collectibility of principal or interest is not reasonably assured, which for a single-family loan we have determined, based on our historical experience, to be when the loan becomes two months or more past due according to its contractual terms. Interest previously accrued but not collected is reversed through interest income at the date a loan is placed on nonaccrual status. We return a non-modified single-family loan to accrual status at the point that the borrower brings the loan current. We return a modified single-family loan to accrual status at the point that the borrower successfully makes all required payments during the trial period (generally three to four months) and the modification is made permanent. We place a multifamily loan on nonaccrual status when the loan becomes three months or more past due according to its contractual terms or is deemed to be individually impaired, unless the loan is well secured such that collectibility of principal and accrued interest is reasonably assured. We return a multifamily loan to accrual status when the borrower cures the delinquency of the loan or we otherwise determine that the loan is well secured such that collectibility is reasonably assured.
Troubled Debt Restructurings [Policy Text Block]	A modification to the contractual terms of a loan that results in granting a concession to a borrower experiencing financial difficulties is considered a TDR.

Allowance for Loan Losses (Poli

Allowance for Loan Losses (Policies)	3 Months Ended
Allowance for Loan Losses (Policies)	Mar. 31, 2019
Receivables [Abstract]
Allowance for Loan Losses [Policy Text Block]	We maintain an allowance for loan losses for HFI loans held by Fannie Mae and by consolidated Fannie Mae MBS trusts, excluding loans for which we have elected the fair value option. When calculating our allowance for loan losses, we consider the unpaid principal balance, net of amortized premiums and discounts, and other cost basis adjustments of HFI loans at the balance sheet date. We record charge-offs as a reduction to our allowance for loan losses at the point of foreclosure, completion of a short sale, upon the redesignation of loans from HFI to HFS or when a loan is determined to be uncollectible. We aggregate single-family HFI loans that are not individually impaired based on similar risk characteristics, for purposes of estimating incurred credit losses and establishing a collective single-family loss reserve using an econometric model that derives an overall loss reserve estimate. We base our allowance methodology on historical events and trends, such as loss severity (in event of default), default rates, and recoveries from mortgage insurance contracts and other credit enhancements that provide loan level loss coverage and are either contractually attached to a loan or that were entered into contemporaneously with and in contemplation of a guaranty or loan purchase transaction. We use recent regional historical sales and appraisal information, including the sales of our own foreclosed properties, to develop our loss severity estimates for all loan categories. Our allowance calculation also incorporates a loss confirmation period (the anticipated time lag between a credit loss event and the confirmation of the credit loss resulting from that event) to ensure our allowance estimate captures credit losses that have been incurred as of the balance sheet date but have not been confirmed. In addition, management performs a review of the observable data used in its estimate to ensure it is representative of prevailing economic conditions and other events existing as of the balance sheet date. Individually impaired single-family loans currently include those classified as a TDR and acquired credit-impaired loans. We consider a loan to be impaired when, based on current information, it is probable that we will not receive all amounts due, including interest, in accordance with the contractual terms of the loan agreement. When a loan has been restructured, we measure impairment using a cash flow analysis discounted at the loan’s original effective interest rate. If we expect to recover our recorded investment in an individually impaired loan through probable foreclosure of the underlying collateral, we measure impairment based on the 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. We establish a collective allowance for all loans in our multifamily guaranty book of business that are not individually measured for impairment using an internal model that applies loss factors to loans in similar risk categories. Our loss factors are developed based on our historical default and loss severity experience. We identify multifamily loans for evaluation for impairment through a credit risk assessment process. If we determine that a multifamily loan is individually impaired, we generally measure impairment on that loan based on the fair value of the underlying collateral less estimated costs to sell the property, as we have concluded that such loans are collateral dependent. We evaluate collectively for impairment smaller-balance homogeneous multifamily loans.

Investment in Securities (Polic

Investment in Securities (Policies)	3 Months Ended
Investment in Securities (Policies)	Mar. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Available-for-sale 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 We record available-for-sale (“AFS”) securities at fair value with unrealized gains and losses, recorded net of tax, as a component of “Other comprehensive loss” and we recognize realized gains and losses from the sale of AFS securities in “ Investment gains, net

Derivative Instruments (Policie

Derivative Instruments (Policies)	3 Months Ended
Derivative Instruments (Policies)	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives, Policy [Policy Text Block]	We recognize all derivatives as either assets or liabilities in our condensed consolidated balance sheets at their fair value on a trade date basis. Fair value amounts, which are netted to the extent a legal right of offset exists and is enforceable by law at the counterparty level and are inclusive of the right or obligation associated with the cash collateral posted or received, are recorded in “Other assets” or “Other liabilities” in our condensed consolidated balance sheets. See “ Note 13, Fair Value

Segment Reporting (Policies)

Segment Reporting (Policies)	3 Months Ended
Segment Reporting (Policies)	Mar. 31, 2019
Segment Reporting [Abstract]
Segment Reporting, Policy [Policy Text Block]	We have two reportable business segments: Single-Family and Multifamily. Results of our two

Netting Arrangements (Policies)

Netting Arrangements (Policies)	3 Months Ended
Netting Arrangements (Policies)	Mar. 31, 2019
Offsetting [Abstract]
Derivatives, Offsetting Policy [Policy Text Block]	Derivative instruments are recorded at fair value and securities purchased under agreements to resell or similar arrangements are recorded at amortized cost in our condensed consolidated balance sheets. For how we determine our rights to offset the assets and liabilities presented above with the same counterparty, including collateral posted or received, see “ Note 14, Netting Arrangements ” in our 2018

Fair Value (Policies)

Fair Value (Policies)	3 Months Ended
Fair Value (Policies)	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurement, Policy [Policy Text Block]	Fair Value MeasurementFair value measurement guidance defines fair value, establishes a framework for measuring fair value, and sets forth disclosures around fair value measurements. This guidance applies whenever other accounting guidance requires or permits assets or liabilities to be measured at fair value. The guidance establishes a three-level fair value hierarchy that prioritizes the inputs into the valuation techniques used to measure fair value. The fair value hierarchy gives the highest priority, Level 1, to measurements based on unadjusted quoted prices in active markets for identical assets or liabilities. The next highest priority, Level 2, is given to measurements of assets and liabilities based on limited observable inputs or observable inputs for similar assets and liabilities. The lowest priority, Level 3, is given to measurements based on unobservable inputs. Fair Value Option We elected the fair value option for loans and debt that contain embedded derivatives that would otherwise require bifurcation. Additionally, we elected the fair value option for our credit risk-sharing securities accounted for as debt of Fannie Mae issued under our CAS series prior to January 1, 2016. Under the fair value option, we elected to carry these instruments at fair value instead of bifurcating the embedded derivative from such instruments.

Commitments and Contingencies (

Commitments and Contingencies (Policies)	3 Months Ended
Commitments and Contingencies (Policies)	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies, Policy [Policy Text Block]	On a quarterly basis, we review relevant information about all pending legal actions and proceedings for the purpose of evaluating and revising our contingencies, accruals and disclosures. We establish an accrual only for matters when a loss is probable and we can reasonably estimate the amount of such loss.

Consolidations and Transfers _3

Consolidations and Transfers of Financial Assets (Tables)	3 Months Ended
Consolidations and Transfers of Financial Assets (Tables)	Mar. 31, 2019
Consolidations and Transfers of Financial Assets [Abstract]
Unconsolidated Variable Interest Entities [Table Text Block]	The following table displays the carrying amount and classification of our assets and liabilities that relate to our involvement with unconsolidated securitization trusts. As of March 31, 2019 December 31, 2018 Assets and liabilities recorded in our condensed consolidated balance sheets related to mortgage-backed trusts: (Dollars in millions) Assets: Trading securities: Fannie Mae $ 1,543 $ 1,422 Non-Fannie Mae 4,212 4,809 Total trading securities 5,755 6,231 Available-for-sale securities: Fannie Mae 1,660 1,704 Non-Fannie Mae 1,046 1,207 Total available-for-sale securities 2,706 2,911 Other assets 65 66 Other liabilities (97 ) (101 ) Net carrying amount $ 8,429 $ 9,107

Mortgage Loans (Tables)

Mortgage Loans (Tables)	3 Months Ended
Mortgage Loans (Tables)	Mar. 31, 2019
SEC Schedule, 12-29, Real Estate Companies, Investment in 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 March 31, 2019 December 31, 2018 (Dollars in millions) Single-family $ 2,930,649 $ 2,929,925 Multifamily 302,152 293,858 Total unpaid principal balance of mortgage loans 3,232,801 3,223,783 Cost basis and fair value adjustments, net 40,196 39,815 Allowance for loan losses for loans held for investment (13,232 ) (14,203 ) Total mortgage loans $ 3,259,765 $ 3,249,395 The following table displays information about our redesignated mortgage loans. For the Three Months Ended March 31, 2019 2018 (Dollars in millions) Carrying value of loans redesignated from HFI to HFS $ 2,611 $ 7,367 Carrying value of loans redesignated from HFS to HFI 9 18 Loans sold - unpaid principal balance 58 748 Realized gains on sale of mortgage loans 36 2 As of March 31, 2019 December 31, 2018 Single-Family Multifamily Total Single-Family Multifamily Total (Dollars in millions) Allowance for loan losses by segment: Individually impaired loans (1) $ (12,291 ) $ (44 ) $ (12,335 ) $ (13,255 ) $ (40 ) $ (13,295 ) Collectively reserved loans (694 ) (203 ) (897 ) (714 ) (194 ) (908 ) Total allowance for loan losses $ (12,985 ) $ (247 ) $ (13,232 ) $ (13,969 ) $ (234 ) $ (14,203 ) Recorded investment in loans by segment: Individually impaired loans (1) $ 114,223 $ 659 $ 114,882 $ 117,561 $ 542 $ 118,103 Collectively reserved loans 2,844,196 303,738 3,147,934 2,841,943 295,122 3,137,065 Total recorded investment in loans $ 2,958,419 $ 304,397 $ 3,262,816 $ 2,959,504 $ 295,664 $ 3,255,168 (1)
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 March 31, 2019 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 $ 29,620 $ 7,397 $ 14,601 $ 51,618 $ 2,821,187 $ 2,872,805 $ 24 $ 25,710 Government (2) 48 16 162 226 20,901 21,127 162 — Alt-A 2,470 803 1,779 5,052 45,750 50,802 1 2,998 Other 772 281 676 1,729 11,956 13,685 3 1,080 Total single-family 32,910 8,497 17,218 58,625 2,899,794 2,958,419 190 29,788 Multifamily (3) 3 N/A 193 196 304,201 304,397 — 509 Total $ 32,913 $ 8,497 $ 17,411 $ 58,821 $ 3,203,995 $ 3,262,816 $ 190 $ 30,297 As of December 31, 2018 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 $ 30,471 $ 7,881 $ 14,866 $ 53,218 $ 2,816,047 $ 2,869,265 $ 22 $ 26,170 Government (2) 57 17 169 243 21,887 22,130 169 — Alt-A 2,332 821 1,844 4,997 48,274 53,271 2 3,082 Other 804 283 713 1,800 13,038 14,838 2 1,128 Total single-family 33,664 9,002 17,592 60,258 2,899,246 2,959,504 195 30,380 Multifamily (3) 56 N/A 171 227 295,437 295,664 — 492 Total $ 33,720 $ 9,002 $ 17,763 $ 60,485 $ 3,194,683 $ 3,255,168 $ 195 $ 30,872 (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
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 March 31, 2019 December 31, 2018 Unpaid Principal Balance Total Recorded Investment Related Allowance for Loan Losses Unpaid Principal Balance Total Recorded Investment Related Allowance for Loan Losses (Dollars in millions) Individually impaired loans: With related allowance recorded: Single-family: Primary $ 79,713 $ 76,804 $ (8,816 ) $ 81,791 $ 78,688 $ (9,406 ) Government 265 270 (55 ) 264 270 (55 ) Alt-A 15,486 14,178 (2,526 ) 16,576 15,158 (2,793 ) Other 4,987 4,706 (894 ) 5,482 5,169 (1,001 ) Total single-family 100,451 95,958 (12,291 ) 104,113 99,285 (13,255 ) Multifamily 297 298 (44 ) 197 196 (40 ) Total individually impaired loans with related allowance recorded 100,748 96,256 (12,335 ) 104,310 99,481 (13,295 ) With no related allowance recorded: (1) Single-family: Primary 16,089 15,325 — 15,939 15,191 — Government 61 57 — 61 56 — Alt-A 2,508 2,248 — 2,628 2,363 — Other 688 635 — 718 666 — Total single-family 19,346 18,265 — 19,346 18,276 — Multifamily 360 361 — 343 346 — Total individually impaired loans with no related allowance recorded 19,706 18,626 — 19,689 18,622 — Total individually impaired loans (2) $ 120,454 $ 114,882 $ (12,335 ) $ 123,999 $ 118,103 $ (13,295 ) (1) The discounted cash flows or collateral value equals or exceeds the carrying value of the loan and, as such, no valuation allowance is required. (2) Includes single-family loans restructured in a TDR with a recorded investment of $113.9 billion and $117.2 billion as of March 31, 2019 and December 31, 2018 , respectively. Includes multifamily loans restructured in a TDR with a recorded investment of $188 million and $187 million as of March 31, 2019 and December 31, 2018 , respectively. For the Three Months Ended March 31, 2019 2018 Average Recorded Investment Total Interest Income Recognized Interest Income Recognized on a Cash Basis Average Recorded Investment Total Interest Income Recognized Interest Income Recognized on a Cash Basis (Dollars in millions) Individually impaired loans: With related allowance recorded: Single-family: Primary $ 77,842 $ 817 $ 80 $ 88,411 $ 911 $ 107 Government 272 3 — 276 3 — Alt-A 14,687 156 11 20,708 212 16 Other 4,940 45 4 7,854 71 5 Total single-family 97,741 1,021 95 117,249 1,197 128 Multifamily 247 2 — 258 — — Total individually impaired loans with related allowance recorded 97,988 1,023 95 117,507 1,197 128 With no related allowance recorded: (1) Single-family: Primary 15,195 220 28 15,007 243 26 Government 56 1 — 60 — — Alt-A 2,293 39 2 2,842 58 4 Other 648 8 1 900 16 1 Total single-family 18,192 268 31 18,809 317 31 Multifamily 353 2 — 331 2 — Total individually impaired loans with no related allowance recorded 18,545 270 31 19,140 319 31 Total individually impaired loans $ 116,533 $ 1,293 $ 126 $ 136,647 $ 1,516 $ 159 (1)
Troubled Debt Restructurings Activity [Table Text Block]	The following table displays the number of loans and recorded investment in loans classified as a TDR. For the Three Months Ended March 31, 2019 2018 Number of Loans Recorded Investment (1) Number of Loans Recorded Investment (1) (Dollars in millions) Single-family: Primary 12,957 $ 1,971 41,679 $ 6,524 Government 23 4 48 4 Alt-A 766 97 2,182 283 Other 147 27 445 84 Total single-family 13,893 2,099 44,354 6,895 Multifamily 3 13 8 42 Total TDRs 13,896 $ 2,112 44,362 $ 6,937 (1) For the Three Months Ended March 31, 2019 2018 Number of Loans Recorded Investment Number of Loans Recorded Investment (Dollars in millions) Single-family: Primary 4,516 $ 673 4,818 $ 701 Government 18 3 14 2 Alt-A 471 73 677 109 Other 154 28 195 38 Total single-family 5,159 777 5,704 850 Multifamily — — 1 2 Total TDRs that subsequently defaulted 5,159 $ 777 5,705 $ 852
Single-family [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in 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 March 31, 2019 (1) December 31, 2018 (1) Primary Alt-A Other Primary Alt-A Other (Dollars in millions) Estimated mark-to-market loan-to-value (“LTV”) ratio: (2) Less than or equal to 80% $ 2,496,412 $ 43,554 $ 11,362 $ 2,521,766 $ 45,476 $ 12,291 Greater than 80% and less than or equal to 90% 239,373 3,555 1,074 228,614 3,804 1,195 Greater than 90% and less than or equal to 100% 126,992 1,837 584 109,548 1,997 645 Greater than 100% 10,028 1,856 665 9,337 1,994 707 Total $ 2,872,805 $ 50,802 $ 13,685 $ 2,869,265 $ 53,271 $ 14,838 (1) Excludes $21.1 billion and $22.1 billion as of March 31, 2019 and December 31, 2018 , 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 class is primarily reverse mortgages for which we do not calculate an estimated mark-to-market LTV ratio. (2)
Multifamily [Member]
SEC Schedule, 12-29, Real Estate Companies, Investment in 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 March 31, December 31, 2019 2018 (Dollars in millions) Credit risk profile by internally assigned grade: Non-classified $ 297,312 $ 289,231 Classified (1) 7,085 6,433 Total $ 304,397 $ 295,664 (1) Represents loans classified as “Substandard,” which have a well-defined weakness that jeopardizes the timely full repayment. Loans with a weakness that makes collection or liquidation in full highly questionable and improbable based on existing conditions and values are referred to as “Doubtful.” As of March 31, 2019 , we had loans with recorded investment of less than $0.5 million classified as doubtful, compared with $1 million as of December 31, 2018

Allowance for Loan Losses (Tabl

Allowance for Loan Losses (Tables)	3 Months Ended
Allowance for Loan Losses (Tables)	Mar. 31, 2019
Receivables [Abstract]
Allowance for Loan Losses Rollforward by Segment [Table Text Block]	The following table displays changes in single-family, multifamily and total allowance for loan losses. For the Three Months Ended March 31, 2019 2018 (Dollars in millions) Single-family allowance for loan losses: Beginning balance $ (13,969 ) $ (18,849 ) Benefit (provision) for loan losses (1) 647 (78 ) Charge-offs 381 465 Recoveries (45 ) (60 ) Other 1 (1 ) Ending balance $ (12,985 ) $ (18,523 ) Multifamily allowance for loan losses: Beginning balance $ (234 ) $ (235 ) Benefit (provision) for loan losses (1) (13 ) 20 Charge-offs — 4 Ending balance $ (247 ) $ (211 ) Total allowance for loan losses: Beginning balance $ (14,203 ) $ (19,084 ) Benefit (provision) for loan losses (1) 634 (58 ) Charge-offs 381 469 Recoveries (45 ) (60 ) Other 1 (1 ) Ending balance $ (13,232 ) $ (18,734 ) (1) Benefit (provision) for loan losses is included in “ Benefit for credit losses
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 March 31, 2019 December 31, 2018 (Dollars in millions) Single-family $ 2,930,649 $ 2,929,925 Multifamily 302,152 293,858 Total unpaid principal balance of mortgage loans 3,232,801 3,223,783 Cost basis and fair value adjustments, net 40,196 39,815 Allowance for loan losses for loans held for investment (13,232 ) (14,203 ) Total mortgage loans $ 3,259,765 $ 3,249,395 The following table displays information about our redesignated mortgage loans. For the Three Months Ended March 31, 2019 2018 (Dollars in millions) Carrying value of loans redesignated from HFI to HFS $ 2,611 $ 7,367 Carrying value of loans redesignated from HFS to HFI 9 18 Loans sold - unpaid principal balance 58 748 Realized gains on sale of mortgage loans 36 2 As of March 31, 2019 December 31, 2018 Single-Family Multifamily Total Single-Family Multifamily Total (Dollars in millions) Allowance for loan losses by segment: Individually impaired loans (1) $ (12,291 ) $ (44 ) $ (12,335 ) $ (13,255 ) $ (40 ) $ (13,295 ) Collectively reserved loans (694 ) (203 ) (897 ) (714 ) (194 ) (908 ) Total allowance for loan losses $ (12,985 ) $ (247 ) $ (13,232 ) $ (13,969 ) $ (234 ) $ (14,203 ) Recorded investment in loans by segment: Individually impaired loans (1) $ 114,223 $ 659 $ 114,882 $ 117,561 $ 542 $ 118,103 Collectively reserved loans 2,844,196 303,738 3,147,934 2,841,943 295,122 3,137,065 Total recorded investment in loans $ 2,958,419 $ 304,397 $ 3,262,816 $ 2,959,504 $ 295,664 $ 3,255,168 (1)

Investments in Securities (Tabl

Investments in Securities (Tables)	3 Months Ended
Investments in Securities (Tables)	Mar. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Investments In Trading Securities [Table Text Block]	The following table displays our investments in trading securities. As of March 31, 2019 December 31, 2018 (Dollars in millions) Mortgage-related securities: Fannie Mae $ 1,583 $ 1,467 Other agency 3,158 3,503 Private-label and other mortgage securities 1,054 1,306 Total mortgage-related securities 5,795 6,276 Non-mortgage-related securities: U.S. Treasury securities 35,020 35,502 Other securities 84 89 Total non-mortgage-related securities 35,104 35,591 Total trading securities $ 40,899 $ 41,867
Schedule of Trading Securities Gains (Losses), Net [Table Text Block]	The following table displays information about our net trading gains. For the Three Months Ended March 31, 2019 2018 (Dollars in millions) Net trading gains $ 92 $ 98 Net trading gains recognized in the period related to securities still held at period end 89 76
Schedule of Realized Gain (Loss) [Table Text Block]	The following table displays the gross realized gains and proceeds on sales of AFS securities. For the Three Months Ended March 31, 2019 2018 (Dollars in millions) Gross realized gains $ 61 $ 363 Total proceeds (excludes initial sale of securities from new portfolio securitizations) 131 635
Schedule of Available-for-sale Securities Reconciliation [Table Text Block]	The following tables display the amortized cost, gross unrealized gains and losses, and fair value by major security type for AFS securities. As of March 31, 2019 Total Amortized Cost (1) Gross Unrealized Gains Gross Unrealized Losses (2) Total Fair Value (Dollars in millions) Fannie Mae $ 1,689 $ 82 $ (19 ) $ 1,752 Other agency 225 17 — 242 Alt-A and subprime private-label securities 246 206 — 452 Mortgage revenue bonds 416 13 (4 ) 425 Other mortgage-related securities 334 9 — 343 Total $ 2,910 $ 327 $ (23 ) $ 3,214 As of December 31, 2018 Total Amortized Cost (1) Gross Unrealized Gains Gross Unrealized Losses (2) Total Fair Value (Dollars in millions) Fannie Mae $ 1,754 $ 69 $ (26 ) $ 1,797 Other agency 239 17 — 256 Alt-A and subprime private-label securities 325 267 — 592 Mortgage revenue bonds 425 13 (4 ) 434 Other mortgage-related securities 336 14 — 350 Total $ 3,079 $ 380 $ (30 ) $ 3,429 (1) Amortized cost consists of unpaid principal balance, unamortized premiums, discounts and other cost basis adjustments, as well as net other-than-temporary impairments (“OTTI”) recognized in “ Investment gains, net ” in our condensed consolidated statements of operations and comprehensive income. (2) Represents the gross unrealized losses on securities for which we have not recognized OTTI, as well as the noncredit component of OTTI and cumulative changes in fair value of securities for which we previously recognized the credit component of OTTI in “ Accumulated other comprehensive income
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 March 31, 2019 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 $ — $ — $ (19 ) $ 372 Mortgage revenue bonds (1 ) 15 (3 ) 3 Total $ (1 ) $ 15 $ (22 ) $ 375 As of December 31, 2018 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 $ — $ — $ (26 ) $ 487 Mortgage revenue bonds (1 ) 24 (3 ) 19 Total $ (1 ) $ 24 $ (29 ) $ 506
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 March 31, 2019 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 $ 1,689 $ 1,752 $ — $ — $ 14 $ 15 $ 114 $ 124 $ 1,561 $ 1,613 Other agency 225 242 — — 23 24 29 32 173 186 Alt-A and subprime private-label securities 246 452 — — — — 1 1 245 451 Mortgage revenue bonds 416 425 2 2 30 30 52 54 332 339 Other mortgage-related securities 334 343 — — — — 28 31 306 312 Total $ 2,910 $ 3,214 $ 2 $ 2 $ 67 $ 69 $ 224 $ 242 $ 2,617 $ 2,901

Financial Guarantees (Tables)

Financial Guarantees (Tables)	3 Months Ended
Financial Guarantees (Tables)	Mar. 31, 2019
Guarantees [Abstract]
Financial Guarantees and Maximum Recovery [Table Text Block]	The following table displays our off-balance sheet maximum exposure, guaranty obligation recognized in our condensed consolidated balance sheets and the potential maximum recovery from third parties through available credit enhancements and recourse related to our financial guarantees. As of March 31, 2019 December 31, 2018 Maximum Exposure Guaranty Obligation Maximum Recovery (1) Maximum Exposure Guaranty Obligation Maximum Recovery (1) (Dollars in millions) Unconsolidated Fannie Mae MBS $ 7,102 $ 29 $ 6,699 $ 7,278 $ 30 $ 6,811 Other guaranty arrangements (2) 13,626 141 2,709 13,847 130 2,711 Total $ 20,728 $ 170 $ 9,408 $ 21,125 $ 160 $ 9,522 (1) 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 13, Concentrations of Credit Risk” in our 2018 Form 10-K and “ Note 11, Concentrations of Credit Risk ” in this report. (2)

Short-Term and Long-Term Debt (

Short-Term and Long-Term Debt (Tables)	3 Months Ended
Short-Term and Long-Term Debt (Tables)	Mar. 31, 2019
Debt Disclosure [Abstract]
Short-Term Debt [Table Text Block]	The following table displays our outstanding short-term debt (debt with an original contractual maturity of one year or less) and weighted-average interest rates of this debt. As of March 31, 2019 December 31, 2018 Outstanding Weighted- Average Interest Rate (1) Outstanding Weighted- Average Interest Rate (1) (Dollars in millions) Short-term debt of Fannie Mae $ 23,071 2.33 % $ 24,896 2.29 % (1)
Long-Term Debt [Table Text Block]	The following table displays our outstanding long-term debt. As of March 31, 2019 December 31, 2018 Maturities Outstanding Weighted- Average Interest Rate (1) Maturities Outstanding Weighted- Average Interest Rate (1) (Dollars in millions) Senior fixed: Benchmark notes and bonds 2019 - 2030 $ 97,710 2.46 % 2019 - 2030 $ 103,206 2.36 % Medium-term notes (2) 2019 - 2026 57,220 1.48 2019 - 2026 61,455 1.48 Other (3) 2019 - 2038 6,675 4.61 2019 - 2038 6,683 4.62 Total senior fixed 161,605 2.20 171,344 2.13 Senior floating: Medium-term notes (2) 2020 - 2020 5,574 2.47 2019 - 2020 4,174 2.36 Connecticut Avenue Securities (4) 2023 - 2031 25,064 6.13 2023 - 2031 25,641 5.97 Other (5) 2020 - 2037 376 7.85 2020 - 2037 351 10.19 Total senior floating 31,014 5.50 30,166 5.52 Subordinated debentures 2019 5,502 9.67 2019 5,617 9.64 Secured borrowings (6) 2021 - 2022 46 2.06 2021 - 2022 51 1.96 Total long-term debt of Fannie Mae (7) 198,167 2.93 207,178 2.83 Debt of consolidated trusts 2019 - 2058 3,173,772 3.06 2019 - 2058 3,159,846 3.03 Total long-term debt $ 3,371,939 3.06 % $ 3,367,024 3.02 % (1) Includes the effects of discounts, premiums and other cost basis adjustments. (2) Includes long-term debt with an original contractual maturity of greater than 1 year and up to 10 years, excluding zero-coupon debt. (3) Includes other long-term debt with an original contractual maturity of greater than 10 years and foreign exchange bonds. (4) Credit risk-sharing securities that transfer a portion of the credit risk on specified pools of single-family mortgage loans to the investors in these securities, a portion of which is reported at fair value. Represents Connecticut Avenue Securities issued prior to the implementation of our CAS REMIC structure in November 2018. See “Note 2, Consolidations and Transfers of Financial Assets” in our 2018 Form 10-K for more information about our CAS REMIC structure. (5) Consists of structured debt instruments that are reported at fair value. (6) Represents our remaining liability resulting from the transfer of financial assets from our condensed consolidated balance sheets that did not qualify as a sale under the accounting guidance for the transfer of financial instruments. (7) Includes unamortized discounts and premiums, other cost basis adjustments and fair value adjustments of $213 million and $413 million as of March 31, 2019 and December 31, 2018

Derivative Instruments (Tables)

Derivative Instruments (Tables)	3 Months Ended
Derivative Instruments (Tables)	Mar. 31, 2019
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 March 31, 2019 As of December 31, 2018 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 $ 70,599 $ 171 $ 22,538 $ (823 ) $ 71,416 $ 438 $ 21,253 $ (740 ) Receive-fixed 89,157 1,037 53,059 (541 ) 88,799 1,113 58,399 (860 ) Basis 273 129 — — 250 104 624 — Foreign currency 226 35 228 (66 ) 221 22 223 (72 ) Swaptions: Pay-fixed 5,350 46 5,625 (45 ) 10,375 191 1,000 (4 ) Receive-fixed 1,100 51 6,375 (287 ) 500 20 7,375 (338 ) Futures (1) 21,594 — — — 16,631 — — — Total gross risk management derivatives 188,299 1,469 87,825 (1,762 ) 188,192 1,888 88,874 (2,014 ) Accrued interest receivable (payable) — 395 — (462 ) — 400 — (419 ) Netting adjustment (2) — (1,781 ) — 2,126 — (2,266 ) — 2,315 Total net risk management derivatives $ 188,299 $ 83 $ 87,825 $ (98 ) $ 188,192 $ 22 $ 88,874 $ (118 ) Mortgage commitment derivatives: Mortgage commitments to purchase whole loans $ 3,901 $ 26 $ 2,153 $ (3 ) $ 4,370 $ 29 $ 57 $ — Forward contracts to purchase mortgage-related securities 53,514 403 9,649 (10 ) 40,650 349 1,045 (3 ) Forward contracts to sell mortgage-related securities 10,547 10 86,515 (653 ) 292 1 70,593 (645 ) Total mortgage commitment derivatives 67,962 439 98,317 (666 ) 45,312 379 71,695 (648 ) Credit enhancement derivatives 32,745 62 2,874 (29 ) 33,431 57 919 (11 ) Derivatives at fair value $ 289,006 $ 584 $ 189,016 $ (793 ) $ 266,935 $ 458 $ 161,488 $ (777 ) (1) Futures have no ascribable fair value because the positions are settled daily. (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 $882 million and $713 million as of March 31, 2019 and December 31, 2018 , respectively. Cash collateral received was $537 million and $664 million as of March 31, 2019 and December 31, 2018
Fair Value Gain (Loss), Net [Table Text Block]	The following table displays, by type of derivative instrument, the fair value gains and losses, net on our derivatives. For the Three Months Ended March 31, 2019 2018 (Dollars in millions) Risk management derivatives: Swaps: Pay-fixed $ (1,335 ) $ 2,783 Receive-fixed 1,281 (2,387 ) Basis 24 (23 ) Foreign currency 19 16 Swaptions: Pay-fixed (177 ) 129 Receive-fixed 7 (16 ) Futures 59 8 Net accrual of periodic settlements (266 ) (215 ) Total risk management derivatives fair value gains (losses), net (388 ) 295 Mortgage commitment derivatives fair value gains (losses), net (300 ) 564 Credit enhancement derivatives fair value gains (losses), net (7 ) 4 Total derivatives fair value gains (losses), net $ (695 ) $ 863

Segment Reporting (Tables)

Segment Reporting (Tables)	3 Months Ended
Segment Reporting (Tables)	Mar. 31, 2019
Segment Reporting [Abstract]
Segment results [Table Text Block]	The following table displays our segment results. For the Three Months Ended March 31, 2019 2018 Single-Family Multifamily Total Single-Family Multifamily Total (Dollars in millions) Net interest income (1) $ 4,039 $ 694 $ 4,733 $ 4,561 $ 671 $ 5,232 Fee and other income (2) 106 121 227 158 162 320 Net revenues 4,145 815 4,960 4,719 833 5,552 Investment gains, net (3) 94 39 133 242 8 250 Fair value gains (losses), net (4) (887 ) 56 (831 ) 1,034 11 1,045 Administrative expenses (631 ) (113 ) (744 ) (643 ) (107 ) (750 ) Credit-related income (expense) (5) Benefit (provision) for credit losses 661 (11 ) 650 196 21 217 Foreclosed property income (expense) (143 ) 3 (140 ) (162 ) — (162 ) Total credit-related income (expense) 518 (8 ) 510 34 21 55 TCCA fees (6) (593 ) — (593 ) (557 ) — (557 ) Other expenses, net (337 ) (71 ) (408 ) (132 ) (71 ) (203 ) Income before federal income taxes 2,309 718 3,027 4,697 695 5,392 Provision for federal income taxes (484 ) (143 ) (627 ) (1,016 ) (115 ) (1,131 ) Net income $ 1,825 $ 575 $ 2,400 $ 3,681 $ 580 $ 4,261 (1) Net interest income primarily consists of guaranty fees received as compensation for assuming and managing the credit risk on loans underlying Fannie Mae MBS held by third parties for the respective business segment, and the difference between the interest income earned on the respective business segment’s mortgage assets in our retained mortgage portfolio and the interest expense associated with the debt funding those assets. Revenues from single-family guaranty fees include revenues generated by the 10 basis point increase in guaranty fees pursuant to the TCCA, the incremental revenue from which is remitted to Treasury and not retained by us. (2) Single-Family fee and other income primarily consists of compensation for engaging in structured transactions and providing other lender services, and income resulting from settlement agreements resolving certain claims relating to private-label securities we purchased or that we have guaranteed. Multifamily fee and other income consists of fees associated with multifamily business activities, including yield maintenance income. (3) Investment gains and losses primarily consists of gains and losses on the sale of mortgage assets for the respective business segment. (4) Single-Family fair value gains and losses primarily consist of fair value gains and losses on risk management and mortgage commitment derivatives, trading securities and other financial instruments associated with our single-family total book of business. Multifamily fair value gains and losses primarily consist of fair value gains and losses on MBS commitment derivatives, trading securities and other financial instruments associated with our multifamily total book of business. (5) Credit-related income or expense is based on the guaranty book of business of the respective business segment and consists of the applicable segment’s benefit or provision for credit losses and foreclosed property income or expense on loans underlying the segment’s guaranty book of business. (6)

Equity (Tables)

Equity (Tables)	3 Months Ended
Equity (Tables)	Mar. 31, 2019
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following table displays our accumulated other comprehensive income (“AOCI”), net of tax, by major categories. As of March 31, December 31, 2019 2018 (Dollars in millions) Net unrealized gains on AFS securities for which we have not recorded OTTI $ 67 $ 52 Net unrealized gains on AFS securities for which we have recorded OTTI 173 224 Other 43 46 Accumulated other comprehensive income $ 283 $ 322 For the Three Months Ended March 31, 2019 2018 AFS (1) Other Total AFS (1) Other Total (Dollars in millions) Beginning balance $ 276 $ 46 $ 322 $ 510 $ 43 $ 553 Reclassification of accumulated other comprehensive income to retained earnings resulting from the enactment of the Tax Cuts and Jobs Act (2) — — — 110 7 117 Other comprehensive income (loss) before reclassifications 8 — 8 (57 ) — (57 ) Amounts reclassified from other comprehensive loss (44 ) (3 ) (47 ) (263 ) (3 ) (266 ) Net other comprehensive loss (36 ) (3 ) (39 ) (320 ) (3 ) (323 ) Ending balance $ 240 $ 43 $ 283 $ 300 $ 47 $ 347 (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 net impairment in earnings, which are recorded in “ Investment gains, net ” in our condensed consolidated statements of operations and comprehensive income. (2) Reclassification from AOCI to retained earnings for the tax effects resulting from the enactment of tax legislation on December 22, 2017 that reduced the federal corporate income tax rate from 35% to 21%

Concentrations of Credit Risk (

Concentrations of Credit Risk (Tables)	3 Months Ended
Concentrations of Credit Risk (Tables)	Mar. 31, 2019
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 guaranty book of business. As of March 31, 2019 (1) December 31, 2018 (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) 1.15 % 0.31 % 0.67 % 1.17 % 0.32 % 0.69 % Percentage of single-family conventional loans (4) 1.32 0.35 0.74 1.37 0.38 0.76
Schedule of Risk Characteristics Guaranty Book of Business [Table Text Block]	As of March 31, 2019 (1) December 31, 2018 (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 LTV ratio: Greater than 100% * 9.35 % * 9.85 % Geographical distribution: California 19 0.34 19 0.34 Florida 6 1.03 6 1.16 New Jersey 3 1.32 4 1.38 New York 5 1.38 5 1.40 All other states 67 0.72 66 0.75 Product distribution: Alt-A 2 3.31 2 3.35 Vintages: 2004 and prior 3 2.68 3 2.69 2005-2008 4 4.50 5 4.61 2009-2019 93 0.33 92 0.34 * Represents less than 0.5% of single-family conventional business volume or book of business. (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 single-family conventional guaranty book of business as of March 31, 2019 and December 31, 2018 . (2) Consists of single-family conventional loans that were 90 days or more past due or in the foreclosure process as of March 31, 2019 and December 31, 2018 . (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)
Schedule of Risk in Force Mortgage Insurance Coverage [Table Text Block]	The following table displays our total mortgage insurance risk in force by primary and pool insurance, as well as the total risk in force mortgage insurance coverage as a percentage of the single-family guaranty book of business. As of March 31, 2019 December 31, 2018 Risk in Force Percentage of Single-Family Guaranty Book of Business Risk in Force Percentage of Single-Family Guaranty Book of Business (Dollars in millions) Mortgage insurance risk in force: Primary mortgage insurance $ 154,823 $ 152,379 Pool mortgage insurance 400 409 Total mortgage insurance risk in force $ 155,223 5% $ 152,788 5%
Schedule of Risk in Force Mortgage Insurance Coverage, by Counterparty [Table Text Block]	The table below displays our mortgage insurer counterparties that provided approximately 10% or more of the risk in force mortgage insurance coverage on mortgage loans in our single-family guaranty book of business. Percentage of Risk in Force Coverage by Mortgage Insurer As of March 31, 2019 December 31, 2018 Counterparty: (1) Arch Capital Group Ltd. 24 % 25 % Radian Guaranty, Inc. 21 21 Mortgage Guaranty Insurance Corp. 18 18 Genworth Mortgage Insurance Corp. (2) 15 15 Essent Guaranty, Inc. 12 12 Others 10 9 Total 100 % 100 % (1)
Schedules of Concentration of Risk, by Risk Factor [Table Text Block]	The table below displays the percentage of our single-family guaranty book of business serviced by our top five depository single-family mortgage servicers and top five non-depository single-family mortgage servicers, and identifies one servicer that serviced more than 10% of our single-family guaranty book of business based on unpaid principal balance. Percentage of Single-Family Guaranty Book of Business As of March 31, 2019 December 31, 2018 Wells Fargo Bank, N.A. (together with its affiliates) 18 % 18 % Remaining top five depository servicers 15 16 Top five non-depository servicers 25 22 Total 58 % 56 %
Multifamily [Member]
Concentration Risk [Line Items]
Schedule of Delinquency Status Guaranty Book of Business [Table Text Block]	As of March 31, 2019 (1) December 31, 2018 (1) 30 Days Delinquent Seriously Delinquent (2) 30 Days Delinquent Seriously Delinquent (2) Percentage of multifamily guaranty book of business * 0.07 % 0.02 % 0.06 %
Schedule of Risk Characteristics Guaranty Book of Business [Table Text Block]	As of March 31, 2019 December 31, 2018 Percentage of Multifamily Guaranty Book of Business (1) Percentage Seriously Delinquent (2)(3) Percentage of Multifamily Guaranty Book of Business (1) Percentage Seriously Delinquent (2)(3) Original LTV ratio: Greater than 80% 1 % — % 1 % — % Less than or equal to 80% 99 0.07 99 0.06 Current DSCR below 1.0 (4) 2 0.62 2 1.38 * Represents less than 0.005% of multifamily loans that were 30 days delinquent. (1) 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. (2) Consists of multifamily loans that were 60 days or more past due as of the dates indicated. (3) 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 multifamily guaranty book of business. (4) 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
Schedules of Concentration of Risk, by Risk Factor [Table Text Block]	The table below displays the percentage of our multifamily guaranty book of business serviced by our top five multifamily mortgage servicers, and identifies two servicers that serviced 10% or more of our multifamily guaranty book of business based on unpaid principal balance. Percentage of Multifamily Guaranty Book of Business As of March 31, 2019 December 31, 2018 Wells Fargo Bank, N.A. (together with its affiliates) 14 % 14 % Walker & Dunlop, LLC 12 12 Remaining top five servicers 22 22 Total 48 % 48 %

Netting Arrangements (Tables)

Netting Arrangements (Tables)	3 Months Ended
Netting Arrangements (Tables)	Mar. 31, 2019
Offsetting [Abstract]
Offsetting [Table Text Block]	The tables below display information related to derivatives, securities purchased under agreements to resell or similar arrangements, and securities sold under agreements to repurchase or similar arrangements, which are subject to an enforceable master netting arrangement or similar agreement that are either offset or not offset in our condensed consolidated balance sheets. As of March 31, 2019 Gross Amount Offset (1) Net Amount Presented in our Condensed Consolidated Balance Sheets Amounts Not Offset in our Condensed Consolidated Balance Sheets Gross Amount Financial Instruments (2) Collateral (3) Net Amount (Dollars in millions) Assets: OTC risk management derivatives $ 1,864 $ (1,801 ) $ 63 $ — $ — $ 63 Cleared risk management derivatives — 20 20 — — 20 Mortgage commitment derivatives 439 — 439 (223 ) (14 ) 202 Total derivative assets 2,303 (1,781 ) 522 (4) (223 ) (14 ) 285 Securities purchased under agreements to resell or similar arrangements (5) 39,850 — 39,850 — (39,850 ) — Total assets $ 42,153 $ (1,781 ) $ 40,372 $ (223 ) $ (39,864 ) $ 285 Liabilities: OTC risk management derivatives $ (2,224 ) $ 2,143 $ (81 ) $ — $ — $ (81 ) Cleared risk management derivatives — (17 ) (17 ) — 10 (7 ) Mortgage commitment derivatives (666 ) — (666 ) 223 416 (27 ) Total derivative liabilities (2,890 ) 2,126 (764 ) (4) 223 426 (115 ) Total liabilities $ (2,890 ) $ 2,126 $ (764 ) $ 223 $ 426 $ (115 ) As of December 31, 2018 Gross Amount Offset (1) Net Amount Presented in our Condensed Consolidated Balance Sheets Amounts Not Offset in our Condensed Consolidated Balance Sheets Gross Amount Financial Instruments (2) Collateral (3) Net Amount (Dollars in millions) Assets: OTC risk management derivatives $ 2,288 $ (2,273 ) $ 15 $ — $ — $ 15 Cleared risk management derivatives — 7 7 — — 7 Mortgage commitment derivatives 379 — 379 (153 ) (7 ) 219 Total derivative assets 2,667 (2,266 ) 401 (4) (153 ) (7 ) 241 Securities purchased under agreements to resell or similar arrangements (5) 48,288 — 48,288 — (48,288 ) — Total assets $ 50,955 $ (2,266 ) $ 48,689 $ (153 ) $ (48,295 ) $ 241 Liabilities: OTC risk management derivatives $ (2,433 ) $ 2,342 $ (91 ) $ — $ — $ (91 ) Cleared risk management derivatives — (27 ) (27 ) — 23 (4 ) Mortgage commitment derivatives (648 ) — (648 ) 153 466 (29 ) Total derivative liabilities (3,081 ) 2,315 (766 ) (4) 153 489 (124 ) Total liabilities $ (3,081 ) $ 2,315 $ (766 ) $ 153 $ 489 $ (124 ) (1) Represents the effect of the right to offset under legally enforceable master netting arrangements to settle with the same counterparty on a net basis, including cash collateral posted and received and accrued interest. (2) Mortgage commitment derivative amounts reflect where we have recognized both an asset and a liability with the same counterparty under an enforceable master netting arrangement but we have not elected to offset the related amounts in our condensed consolidated balance sheets. (3) Represents collateral received that has not been recognized and is not offset in our condensed consolidated balance sheets as well as collateral posted which has been recognized but not offset in our condensed consolidated balance sheets. The fair value of non-cash collateral we pledged was $1.8 billion and $1.9 billion as of March 31, 2019 and December 31, 2018 , respectively, which the counterparty was permitted to sell or repledge. The fair value of non-cash collateral received was $39.9 billion and $48.4 billion , of which $33.9 billion and $45.7 billion could be sold or repledged as of March 31, 2019 and December 31, 2018 , respectively. None of the underlying collateral was sold or repledged as of March 31, 2019 or December 31, 2018 . (4) Excludes derivative assets of $62 million and $57 million as of March 31, 2019 and December 31, 2018 , respectively, and derivative liabilities of $29 million and $11 million recognized in our condensed consolidated balance sheets as of March 31, 2019 and December 31, 2018 , respectively, that are not subject to enforceable master netting arrangements. (5) Includes $17.6 billion and $15.4 billion in securities purchased under agreements to resell classified as “Cash and cash equivalents” in our condensed consolidated balance sheets as of March 31, 2019 and December 31, 2018 , respectively.

Fair Value (Tables)

Fair Value (Tables)	3 Months Ended
Fair Value (Tables)	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Recurring Changes in Fair Value [Table Text Block]	The following tables display our assets and liabilities measured in our condensed consolidated balance sheets at fair value on a recurring basis subsequent to initial recognition, including instruments for which we have elected the fair value option. Fair Value Measurements as of March 31, 2019 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 $ — $ 1,516 $ 67 $ — $ 1,583 Other agency — 3,158 — — 3,158 Private-label and other mortgage securities — 1,054 — — 1,054 Non-mortgage-related securities: U.S. Treasury securities 35,020 — — — 35,020 Other securities — 84 — — 84 Total trading securities 35,020 5,812 67 — 40,899 Available-for-sale securities: Mortgage-related securities: Fannie Mae — 1,553 199 — 1,752 Other agency — 242 — — 242 Alt-A and subprime private-label securities — 429 23 — 452 Mortgage revenue bonds — — 425 — 425 Other — 6 337 — 343 Total available-for-sale securities — 2,230 984 — 3,214 Mortgage loans — 7,818 934 — 8,752 Other assets: Risk management derivatives: Swaps — 1,633 134 — 1,767 Swaptions — 97 — — 97 Netting adjustment — — — (1,781 ) (1,781 ) Mortgage commitment derivatives — 399 40 — 439 Credit enhancement derivatives — — 62 — 62 Total other assets — 2,129 236 (1,781 ) 584 Total assets at fair value $ 35,020 $ 17,989 $ 2,221 $ (1,781 ) $ 53,449 Fair Value Measurements as of March 31, 2019 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 $ — $ 6,306 $ 376 $ — $ 6,682 Total of Fannie Mae — 6,306 376 — 6,682 Of consolidated trusts — 22,826 224 — 23,050 Total long-term debt — 29,132 600 — 29,732 Other liabilities: Risk management derivatives: Swaps — 1,891 1 — 1,892 Swaptions — 332 — — 332 Netting adjustment — — — (2,126 ) (2,126 ) Mortgage commitment derivatives — 663 3 — 666 Credit enhancement derivatives — — 29 — 29 Total other liabilities — 2,886 33 (2,126 ) 793 Total liabilities at fair value $ — $ 32,018 $ 633 $ (2,126 ) $ 30,525 Fair Value Measurements as of December 31, 2018 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: Cash equivalents (2) $ 748 $ — $ — $ — $ 748 Trading securities: Mortgage-related securities: Fannie Mae — 1,435 32 — 1,467 Other agency — 3,503 — — 3,503 Private-label and other mortgage securities — 1,305 1 — 1,306 Non-mortgage-related securities: U.S. Treasury securities 35,502 — — — 35,502 Other Securities — 89 — — 89 Total trading securities 35,502 6,332 33 — 41,867 Available-for-sale securities: Mortgage-related securities: Fannie Mae — 1,645 152 — 1,797 Other agency — 256 — — 256 Alt-A and subprime private-label securities — 568 24 — 592 Mortgage revenue bonds — — 434 — 434 Other — 8 342 — 350 Total available-for-sale securities — 2,477 952 — 3,429 Mortgage loans — 7,985 937 — 8,922 Other assets: Risk management derivatives: Swaps — 1,962 115 — 2,077 Swaptions — 211 — — 211 Netting adjustment — — — (2,266 ) (2,266 ) Mortgage commitment derivatives — 342 37 — 379 Credit enhancement derivatives — — 57 — 57 Total other assets — 2,515 209 (2,266 ) 458 Total assets at fair value $ 36,250 $ 19,309 $ 2,131 $ (2,266 ) $ 55,424 Fair Value Measurements as of December 31, 2018 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 $ — $ 6,475 $ 351 $ — $ 6,826 Total of Fannie Mae — 6,475 351 — 6,826 Of consolidated trusts — 23,552 201 — 23,753 Total long-term debt — 30,027 552 — 30,579 Other liabilities: Risk management derivatives: Swaps — 2,089 2 — 2,091 Swaptions — 342 — — 342 Netting adjustment — — — (2,315 ) (2,315 ) Mortgage commitment derivatives — 646 2 — 648 Credit enhancement derivatives — — 11 — 11 Total other liabilities — 3,077 15 (2,315 ) 777 Total liabilities at fair value $ — $ 33,104 $ 567 $ (2,315 ) $ 31,356 (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. (2)
Fair Value Measurements Using Significant Unobservable Inputs (Level 3) [Table Text Block]	The following tables display a reconciliation of all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3). The tables also display gains and losses due to changes in fair value, including realized and unrealized gains and losses, recognized in our condensed consolidated statements of operations and comprehensive income for Level 3 assets and liabilities. Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Three Months Ended March 31, 2019 Total Gains (Losses) (Realized/Unrealized) Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of March 31, 2019 (5)(6) Net Unrealized Gains (Losses) Included in OCI Related to Assets and Liabilities Still Held as of March 31, 2019 (1) Balance, December 31, 2018 Included in Net Income Included in Total OCI Gain/(Loss) (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 Transfers into Level 3 Balance, March 31, 2019 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 32 $ 2 $ — $ — $ — $ — $ — $ — $ 33 $ 67 $ 2 $ — Private-label and other mortgage securities 1 — — — — — (1 ) — — — — — Total trading securities $ 33 $ 2 (6)(7) $ — $ — $ — $ — $ (1 ) $ — $ 33 $ 67 $ 2 $ — Available-for-sale securities: Mortgage-related: Fannie Mae $ 152 $ — $ 4 $ — $ — $ — $ — $ (41 ) $ 84 $ 199 $ — $ 2 Alt-A and subprime private-label securities 24 — — — — — (1 ) — — 23 — — Mortgage revenue bonds 434 — — — — — (9 ) — — 425 — — Other 342 7 (5 ) — — — (8 ) — 1 337 — (4 ) Total available-for-sale securities $ 952 $ 7 (7)(8) $ (1 ) $ — $ — $ — $ (18 ) $ (41 ) $ 85 $ 984 $ — $ (2 ) Mortgage loans $ 937 $ 14 (6)(7) $ — $ — $ — $ — $ (34 ) $ (28 ) $ 45 $ 934 $ 11 $ — Net derivatives 194 98 (6) — — — — (89 ) — — 203 44 — Long-term debt: Of Fannie Mae: Senior floating (351 ) (25 ) — — — — — — — (376 ) (25 ) — Of consolidated trusts (201 ) (3 ) — — — — 5 49 (74 ) (224 ) (1 ) — Total long-term debt $ (552 ) $ (28 ) (6) $ — $ — $ — $ — $ 5 $ 49 $ (74 ) $ (600 ) $ (26 ) $ — Fair Value Measurements Using Significant Unobservable Inputs (Level 3) For the Three Months Ended March 31, 2018 Total Gains (Losses) (Realized/Unrealized) Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held as of March 31, 2018 (5)(6) Net Unrealized Gains (Losses) Included in OCI Related to Assets and Liabilities Still Held as of March 31, 2018 (1) Balance, December 31, 2017 Included in Net Income Included in Total OCI (Loss) (1) Purchases (2) Sales (2) Issues (3) Settlements (3) Transfers out of Level 3 (4) Transfers into Level 3 Balance, March 31, 2018 (Dollars in millions) Trading securities: Mortgage-related: Fannie Mae $ 971 $ 171 $ — $ 1 $ (1,060 ) $ — $ — $ — $ — $ 83 $ 1 $ — Other agency 35 (1 ) — — — — (1 ) (33 ) — — — — Private-label and other mortgage securities 195 (85 ) — — — — (5 ) (104 ) — 1 — — Total trading securities $ 1,201 $ 85 (6)(7) $ — $ 1 $ (1,060 ) $ — $ (6 ) $ (137 ) $ — $ 84 $ 1 $ — Available-for-sale securities: Mortgage-related: Fannie Mae $ 208 $ — $ (4 ) $ — $ — $ — $ (2 ) $ — $ — $ 202 $ — $ (3 ) Alt-A and subprime private-label securities 77 — (45 ) — — — (1 ) (4 ) — 27 — 1 Mortgage revenue bonds 671 11 (13 ) — (11 ) — (119 ) — — 539 — (8 ) Other 357 7 (2 ) — — — (11 ) — — 351 — — Total available-for-sale securities $ 1,313 $ 18 (7)(8) $ (64 ) $ — $ (11 ) $ — $ (133 ) $ (4 ) $ — $ 1,119 $ — $ (10 ) Mortgage loans $ 1,116 $ 17 (6)(7) $ — $ — $ — $ — $ (48 ) $ (36 ) $ 53 $ 1,102 $ 11 $ — Net derivatives 134 (58 ) (6) — — — — 4 53 — 133 (22 ) — Long-term debt: Of Fannie Mae: Senior floating (376 ) 19 — — — — — — — (357 ) 19 — Of consolidated trusts (582 ) 3 — — — 1 10 154 (48 ) (462 ) 1 — Total long-term debt $ (958 ) $ 22 (6) $ — $ — $ — $ 1 $ 10 $ 154 $ (48 ) $ (819 ) $ 20 $ — (1) Gains (losses) included in other comprehensive loss are included in “Changes in unrealized gains on AFS securities, net of reclassification adjustments and taxes” in our condensed consolidated statements of operations and comprehensive income. (2) Purchases and sales include activity related to the consolidation and deconsolidation of assets of securitization trusts. For the three months ended March 31, 2018, includes the dissolution of a Fannie Mae-wrapped private-label securities trust. (3) Issues and settlements include activity related to the consolidation and deconsolidation of liabilities of securitization trusts. (4) Transfers out of Level 3 during the first quarter of 2018 consisted primarily of mortgage loans of consolidated trusts for which unobservable inputs used in valuations became less significant. Transfers out of Level 3 also included private-label mortgage-related securities backed by Alt-A loans and subprime loans. Prices for these securities were available from multiple third-party vendors and demonstrated an increased and sustained level of observability over time. (5) Amount represents temporary changes in fair value. Amortization, accretion and OTTI are not considered unrealized and are not included in this amount. (6) Gains (losses) are included in “ Fair value gains (losses), net ” in our condensed consolidated statements of operations and comprehensive income. (7) Gains (losses) are included in “ Net interest income ” in our condensed consolidated statements of operations and comprehensive income. (8) Gains (losses) are included in “ Investment gains, net
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, excluding instruments for which we have elected the fair value option. Changes in these unobservable inputs can result in significantly higher or lower fair value measurements of these assets and liabilities as of the reporting date. Fair Value Measurements as of March 31, 2019 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1) (Dollars in millions) Recurring fair value measurements: Trading securities: Mortgage-related securities: Agency (2) $ 67 Various Available-for-sale securities: Mortgage-related securities: Agency (2) $ 105 Consensus 94 Various Total agency 199 Alt-A and subprime private-label securities 23 Various Mortgage revenue bonds 304 Single Vendor Spreads (bps) 16.0 - 265.2 71.2 121 Various Total mortgage revenue bonds 425 Other 289 Discounted Cash Flow Default Rate (%) 4.1 4.1 Prepayment Speed (%) 4.6 4.6 Severity (%) 95.0 95.0 Spreads (bps) 68.2 - 290.0 289.4 48 Various Total other 337 Total available-for-sale securities $ 984 Net derivatives $ 132 Dealer Mark 71 Various Total net derivatives $ 203 Fair Value Measurements as of December 31, 2018 Fair Value Significant Valuation Techniques Significant Unobservable Inputs (1) Range (1) Weighted - Average (1)(2) (Dollars in millions) Recurring fair value measurements: Trading securities: Mortgage-related securities: Agency (2) $ 32 Various Private-label securities and other mortgage securities 1 Various Total trading securities $ 33 Available-for-sale securities: Mortgage-related securities: Agency (2) $ 152 Various Alt-A and subprime private-label securities 24 Various Mortgage revenue bonds 349 Single Vendor Spreads(bps) (0.5 ) - 332.8 59.0 85 Various Total mortgage revenue bonds 434 Other 294 Discounted Cash Flow Default Rate(%) 4.7 4.7 Prepayment Speed(%) 8.2 8.2 Severity(%) 70.0 70.0 Spreads(bps) 75.4 - 390.0 389.1 48 Various Total other 342 Total available-for-sale securities $ 952 Net derivatives $ 113 Dealers Mark 81 Various Total net derivatives $ 194 (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) Unobservable inputs were weighted by the relative fair value of the instruments.
Level 3 Assets Measured on Nonrecurring Basis [Table Text Block]	The following table displays valuation techniques for our Level 3 assets measured at fair value on a nonrecurring basis. The significant unobservable inputs related to these techniques primarily relate to collateral dependent valuations. The related ranges and weighted averages are not meaningful when aggregated as they vary significantly from property to property. Fair Value Measurements as of Valuation Techniques March 31, 2019 December 31, 2018 Nonrecurring fair value measurements: Mortgage loans held for sale, at lower of cost or fair value Consensus $ 1,487 $ 631 Single Vendor 828 1,119 Various 1 — Total mortgage loans held for sale, at lower of cost or fair value 2,316 1,750 Single-family mortgage loans held for investment, at amortized cost Internal Model 609 818 Multifamily mortgage loans held for investment, at amortized cost Asset Manager Estimate 153 102 Various 10 40 Total multifamily mortgage loans held for investment, at amortized cost 163 142 Acquired property, net: (1) Single-family Accepted Offers 153 151 Appraisals 346 419 Walk Forwards 158 181 Internal Model 147 219 Various 37 41 Total single-family 841 1,011 Multifamily Various 5 50 Other assets Various — — Total nonrecurring assets at fair value $ 3,934 $ 3,771 (1) The most commonly used techniques in our valuation of acquired property are proprietary home price model and third-party valuations (both current and walk forward). Based on the number of properties measured as of March 31, 2019 , these methodologies comprised approximately 78% of our valuations, while accepted offers comprised approximately 18% of our valuations. Based on the number of properties measured as of December 31, 2018 , these methodologies comprised approximately 82% of our valuations, while accepted offers comprised approximately 15%
Fair Value of Financial Instruments [Table Text Block]	The following table displays the carrying value and estimated fair value of our financial instruments. The fair value of financial instruments we disclose includes commitments to purchase multifamily and single-family mortgage loans that we do not record in our condensed consolidated balance sheets. The fair values of these commitments are included as “Mortgage loans held for investment, net of allowance for loan losses.” The disclosure excludes all non-financial instruments; therefore, the fair value of our financial assets and liabilities does not represent the underlying fair value of our total consolidated assets and liabilities. As of March 31, 2019 Carrying Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Netting Adjustment Estimated (Dollars in millions) Financial assets: Cash and cash equivalents and restricted cash $ 52,241 $ 34,641 $ 17,600 $ — $ — $ 52,241 Federal funds sold and securities purchased under agreements to resell or similar arrangements 22,250 — 22,250 — — 22,250 Trading securities 40,899 35,020 5,812 67 — 40,899 Available-for-sale securities 3,214 — 2,230 984 — 3,214 Mortgage loans held for sale 10,066 — 2,729 7,931 — 10,660 Mortgage loans held for investment, net of allowance for loan losses 3,249,699 — 2,982,238 275,207 — 3,257,445 Advances to lenders 4,246 — 4,244 2 — 4,246 Derivative assets at fair value 584 — 2,129 236 (1,781 ) 584 Guaranty assets and buy-ups 159 — — 370 — 370 Total financial assets $ 3,383,358 $ 69,661 $ 3,039,232 $ 284,797 $ (1,781 ) $ 3,391,909 Financial liabilities: Short-term debt: Of Fannie Mae $ 23,071 $ — $ 23,078 $ — $ — $ 23,078 Long-term debt: Of Fannie Mae 198,167 — 204,060 813 — 204,873 Of consolidated trusts 3,173,772 — 3,118,819 43,205 — 3,162,024 Derivative liabilities at fair value 793 — 2,886 33 (2,126 ) 793 Guaranty obligations 170 — — 107 — 107 Total financial liabilities $ 3,395,973 $ — $ 3,348,843 $ 44,158 $ (2,126 ) $ 3,390,875 As of December 31, 2018 Carrying Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Netting Adjustment Estimated (Dollars in millions) Financial assets: Cash and cash equivalents and restricted cash $ 49,423 $ 34,073 $ 15,350 $ — $ — $ 49,423 Federal funds sold and securities purchased under agreements to resell or similar arrangements 32,938 — 32,938 — — 32,938 Trading securities 41,867 35,502 6,332 33 — 41,867 Available-for-sale securities 3,429 — 2,477 952 — 3,429 Mortgage loans held for sale 7,701 — 238 7,856 — 8,094 Mortgage loans held for investment, net of allowance for loan losses 3,241,694 — 2,990,104 216,404 — 3,206,508 Advances to lenders 3,356 — 3,354 2 — 3,356 Derivative assets at fair value 458 — 2,515 209 (2,266 ) 458 Guaranty assets and buy-ups 147 — — 356 — 356 Total financial assets $ 3,381,013 $ 69,575 $ 3,053,308 $ 225,812 $ (2,266 ) $ 3,346,429 Financial liabilities: Short-term debt: Of Fannie Mae $ 24,896 $ — $ 24,901 $ — $ — $ 24,901 Long-term debt: Of Fannie Mae 207,178 — 211,403 771 — 212,174 Of consolidated trusts 3,159,846 — 3,064,239 39,043 — 3,103,282 Derivative liabilities at fair value 777 — 3,077 15 (2,315 ) 777 Guaranty obligations 160 — — 121 — 121 Total financial liabilities $ 3,392,857 $ — $ 3,303,620 $ 39,950 $ (2,315 ) $ 3,341,255
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 March 31, 2019 December 31, 2018 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 $ 8,752 $ 6,682 $ 23,050 $ 8,922 $ 6,826 $ 23,753 Unpaid principal balance 8,578 6,050 21,216 8,832 6,241 22,080 (1) Includes nonaccrual loans with a fair value of $145 million and $161 million as of March 31, 2019 and December 31, 2018 , respectively. The difference between unpaid principal balance and the fair value of these nonaccrual loans as of March 31, 2019 and December 31, 2018 was $16 million and $19 million , respectively. Includes loans that are 90 days or more past due with a fair value of $95 million and $102 million as of March 31, 2019 and December 31, 2018 , respectively. The difference between unpaid principal balance and the fair value of these 90 or more days past due loans as of March 31, 2019 and December 31, 2018 was $12 million and $14 million

Summary of Significant Accoun_3

Summary of Significant Accounting Policies Regulatory Capital (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Deficit of core capital over statutory minimum capital requirement	$ (137,800)	$ (137,100)

Summary of Significant Accoun_4

Summary of Significant Accounting Policies Related Parties (Details) - USD ($) $ in Millions	Jun. 30, 2019	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Related Parties [Line Items]
Deficit Of Core Capital Over Statutory Minimum Capital Requirement		$ (137,800)		$ (137,100)
Net worth		5,361		$ 6,240
Payments of cash dividends on senior preferred stock to Treasury		3,240	$ 0
Income Taxes Paid		$ 0	$ 0
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%		35.00%
Weighted Average Number of Shares, Contingently Issuable		4,600,000,000	4,600,000,000
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees		$ 593	$ 557
Basis Points of Each Dollar of Unpaid Principal Balance		0.042%
Trading, at fair value (includes $2,922 and $3,061, respectively, pledged as collateral)		$ 40,899		$ 41,867
Interest Receivable		8,926		8,490
Interest income recognized on Treasury securities		$ 427	$ 236
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Preferred Stock		131,000,000	131,000,000
Scenario, Forecast [Member]
Related Parties [Line Items]
Payments of cash dividends on senior preferred stock to Treasury	$ 2,400
US Treasury [Member]
Related Parties [Line Items]
Aggregate funding received from US Treasury pursuant to the senior preferred stock purchase agreement		$ 119,800
Total available funding from US Treasury pursuant to the senior preferred stock agreement		113,900
Capital Reserve Amount, current year, Senior Preferred Stock Purchase Agreement, Amendment		3,000
Aggregate liquidation preference of senior preferred stock		$ 123,800
Percentage of common shares attributable to warrants issued to US Treasury as percentage to total diluted common shares		79.90%
Home Affordable Modification Program administrative expense reimbursements from Treasury and Freddie Mac		$ 5	$ 7
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees		593	557
Affordable Housing Program Obligation		75
US Treasury [Member] \| Single-family [Member]
Related Parties [Line Items]
Recognized TCCA fees that had not been remitted to Treasury as of period end		593
Federal Housing Finance Agency [Member]
Related Parties [Line Items]
FHFA assessment fees		30	29
Common Securitization Solutions [Member]
Related Parties [Line Items]
Payments to Acquire or Advance to Equity Method Investments		36	41
U.S. Treasury securities [Member]
Related Parties [Line Items]
Trading, at fair value (includes $2,922 and $3,061, respectively, pledged as collateral)		35,020		35,502
Other Expense [Member] \| US Treasury [Member]
Related Parties [Line Items]
Affordable Housing Program Assessments		15	18	75
Accumulated other comprehensive income [Member]
Related Parties [Line Items]
Reclassification related to Tax Cuts and Jobs Act		0	117
Net worth		$ 283	$ 347	$ 322	$ 553

Consolidations and Transfers _4

Consolidations and Transfers of Financial Assets Unconsolidated VIEs (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Variable Interest Entities [Line Items]
Trading, at fair value	$ 40,899	$ 41,867
Available-for-sale, at fair value	3,214	3,429
Other assets	17,839	17,004
Other liabilities	(10,299)	(9,947)
Unpaid principal balance of mortgage loans	3,232,801	3,223,783
Principal Amount Outstanding on Loans Securitized or Asset-backed Financing Arrangement	1,200	1,200
Multifamily [Member]
Variable Interest Entities [Line Items]
Unpaid principal balance of mortgage loans	302,152	293,858
Unconsolidated VIEs [Member] \| Multifamily [Member]
Variable Interest Entities [Line Items]
Total unconsolidated assets	2,900	931
Unpaid principal balance of mortgage loans	302,200
Unconsolidated VIEs [Member] \| Mortgage-related securities [Member]
Variable Interest Entities [Line Items]
Trading, at fair value	5,755	6,231
Available-for-sale, at fair value	2,706	2,911
Other assets	65	66
Other liabilities	(97)	(101)
Net carrying amount	8,429	9,107
Maximum exposure to loss	13,000	14,000
Total unconsolidated assets	70,000	80,000
Unconsolidated VIEs [Member] \| Partnership interest [Member]
Variable Interest Entities [Line Items]
Net carrying amount	82	89
Maximum exposure to loss	103	111
Total unconsolidated assets	2,300	2,300
Unconsolidated VIEs [Member] \| Debt Securities [Member]
Variable Interest Entities [Line Items]
Maximum exposure to loss	2,900	920
Unconsolidated VIEs [Member] \| Fannie Mae Securities [Member]
Variable Interest Entities [Line Items]
Trading, at fair value	1,543	1,422
Available-for-sale, at fair value	1,660	1,704
Unconsolidated VIEs [Member] \| Non-Fannie Mae Securities [Member]
Variable Interest Entities [Line Items]
Trading, at fair value	4,212	4,809
Available-for-sale, at fair value	$ 1,046	$ 1,207

Consolidations and Transfers _5

Consolidations and Transfers of Financial Assets Transfers of Financial Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Transfers of Financial Assets [Line Items]
Portfolio securitizations: unpaid principal balance	$ 41,400	$ 64,300
Unconsolidated VIEs [Member]
Transfers of Financial Assets [Line Items]
Retained interests: principal and interest received	116	$ 226
Unconsolidated VIEs [Member] \| Single Class MBS, REMIC & Megas [Member]
Transfers of Financial Assets [Line Items]
Retained interests: unpaid principal balance	1,600		$ 1,500
Retained interests: fair value	$ 2,300		$ 2,200

Consolidations and Transfers _6

Consolidations and Transfers of Financial Assets Managed Loans (Details) - USD ($) $ in Billions	Mar. 31, 2019	Dec. 31, 2018
Consolidations and Transfers of Financial Assets [Abstract]
Principal Amount Outstanding on Loans Securitized or Asset-backed Financing Arrangement	$ 1.2	$ 1.2

Mortgage Loans Loans in Mortgag

Mortgage Loans Loans in Mortgage Portfolio (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	$ 3,232,801		$ 3,223,783
Cost basis and fair value adjustments, net	40,196		39,815
Allowance for loan losses for loans held for investment	(13,232)	$ (18,734)	(14,203)	$ (19,084)
Total mortgage loans	3,259,765		3,249,395
Carrying value of loans redesignated from HFI to HFS	2,611	7,367
Carrying value of loans redesignated from HFS to HFI	9	18
Loans sold - unpaid principal balance	58	748
Realized gains on sale of mortgage loans	36	$ 2
Single-family [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	2,930,649		2,929,925
Mortgage Loans in Process of Foreclosure, Amount	10,100
Multifamily [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	$ 302,152		$ 293,858

Mortgage Loans Aging (Details)

Mortgage Loans Aging (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mortgage Loans Aging (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	$ 58,821	$ 60,485
Current	3,203,995	3,194,683
Total recorded investment in loans	3,262,816	3,255,168
Recorded investment in loans 90 days or more delinquent and accruing interest	190	195
Recorded investment in nonaccrual loans	30,297	30,872
30 to 59 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	32,913	33,720
60 to 89 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	8,497	9,002
Seriously Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	17,411	17,763
Single-family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	58,625	60,258
Current	2,899,794	2,899,246
Total recorded investment in loans	2,958,419	2,959,504
Recorded investment in loans 90 days or more delinquent and accruing interest	190	195
Recorded investment in nonaccrual loans	29,788	$ 30,380
Table Footnote [Abstract]
Mortgage Loans in Process of Foreclosure, Amount	$ 10,100
Single-family [Member] \| Minimum [Member]
Table Footnote [Abstract]
Serious delinquency, days past due	90 days	90 days
Single-family [Member] \| 30 to 59 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	$ 32,910	$ 33,664
Single-family [Member] \| 60 to 89 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	8,497	9,002
Single-family [Member] \| Seriously Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	17,218	17,592
Single-family [Member] \| Primary [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	51,618	53,218
Current	2,821,187	2,816,047
Total recorded investment in loans	2,872,805	2,869,265
Recorded investment in loans 90 days or more delinquent and accruing interest	24	22
Recorded investment in nonaccrual loans	25,710	26,170
Single-family [Member] \| Primary [Member] \| 30 to 59 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	29,620	30,471
Single-family [Member] \| Primary [Member] \| 60 to 89 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	7,397	7,881
Single-family [Member] \| Primary [Member] \| Seriously Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	14,601	14,866
Single-family [Member] \| Government [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	226	243
Current	20,901	21,887
Total recorded investment in loans	21,127	22,130
Recorded investment in loans 90 days or more delinquent and accruing interest	162	169
Recorded investment in nonaccrual loans	0	0
Single-family [Member] \| Government [Member] \| 30 to 59 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	48	57
Single-family [Member] \| Government [Member] \| 60 to 89 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	16	17
Single-family [Member] \| Government [Member] \| Seriously Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	162	169
Single-family [Member] \| Alt-A [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	5,052	4,997
Current	45,750	48,274
Total recorded investment in loans	50,802	53,271
Recorded investment in loans 90 days or more delinquent and accruing interest	1	2
Recorded investment in nonaccrual loans	2,998	3,082
Single-family [Member] \| Alt-A [Member] \| 30 to 59 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	2,470	2,332
Single-family [Member] \| Alt-A [Member] \| 60 to 89 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	803	821
Single-family [Member] \| Alt-A [Member] \| Seriously Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	1,779	1,844
Single-family [Member] \| Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	1,729	1,800
Current	11,956	13,038
Total recorded investment in loans	13,685	14,838
Recorded investment in loans 90 days or more delinquent and accruing interest	3	2
Recorded investment in nonaccrual loans	1,080	1,128
Single-family [Member] \| Other [Member] \| 30 to 59 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	772	804
Single-family [Member] \| Other [Member] \| 60 to 89 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	281	283
Single-family [Member] \| Other [Member] \| Seriously Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	676	713
Multifamily [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	196	227
Current	304,201	295,437
Total recorded investment in loans	304,397	295,664
Recorded investment in loans 90 days or more delinquent and accruing interest	0	0
Recorded investment in nonaccrual loans	$ 509	$ 492
Multifamily [Member] \| Minimum [Member]
Table Footnote [Abstract]
Serious delinquency, days past due	60 days	60 days
Multifamily [Member] \| Maximum [Member]
Table Footnote [Abstract]
Serious delinquency, days past due	89 days	89 days
Multifamily [Member] \| 30 to 59 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	$ 3	$ 56
Multifamily [Member] \| Seriously Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days delinquent	$ 193	$ 171

Mortgage Loans Credit Quality I

Mortgage Loans Credit Quality Indicators - SF (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	$ 3,262,816	$ 3,255,168
Single-family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	2,958,419	2,959,504
Single-family [Member] \| Primary [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	2,872,805	2,869,265
Single-family [Member] \| Primary [Member] \| Estimated mark-to-market loan-to-value ratio less than or equal to 80% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	2,496,412	2,521,766
Single-family [Member] \| Primary [Member] \| Estimated mark-to-market loan-to-value ratio greater than 80% and less than or equal to 90% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	239,373	228,614
Single-family [Member] \| Primary [Member] \| Estimated mark-to-market loan-to-value ratio greater than 90% and less than or equal to 100% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	126,992	109,548
Single-family [Member] \| Primary [Member] \| Estimated mark-to-market loan-to-value ratio greater than 100% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	10,028	9,337
Single-family [Member] \| Alt-A [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	50,802	53,271
Single-family [Member] \| Alt-A [Member] \| Estimated mark-to-market loan-to-value ratio less than or equal to 80% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	43,554	45,476
Single-family [Member] \| Alt-A [Member] \| Estimated mark-to-market loan-to-value ratio greater than 80% and less than or equal to 90% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	3,555	3,804
Single-family [Member] \| Alt-A [Member] \| Estimated mark-to-market loan-to-value ratio greater than 90% and less than or equal to 100% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	1,837	1,997
Single-family [Member] \| Alt-A [Member] \| Estimated mark-to-market loan-to-value ratio greater than 100% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	1,856	1,994
Single-family [Member] \| Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	13,685	14,838
Single-family [Member] \| Other [Member] \| Estimated mark-to-market loan-to-value ratio less than or equal to 80% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	11,362	12,291
Single-family [Member] \| Other [Member] \| Estimated mark-to-market loan-to-value ratio greater than 80% and less than or equal to 90% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	1,074	1,195
Single-family [Member] \| Other [Member] \| Estimated mark-to-market loan-to-value ratio greater than 90% and less than or equal to 100% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	584	645
Single-family [Member] \| Other [Member] \| Estimated mark-to-market loan-to-value ratio greater than 100% [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	665	707
Single-family [Member] \| Government [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	$ 21,127	$ 22,130

Mortgage Loans Credit Quality_2

Mortgage Loans Credit Quality Indicators - MF (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	$ 3,262,816	$ 3,255,168
Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	304,397	295,664
Multifamily [Member] \| Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	0.5	1
Multifamily [Member] \| Non-Classified [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	297,312	289,231
Multifamily [Member] \| Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in loans	$ 7,085	$ 6,433

Mortgage Loans Individually Imp

Mortgage Loans Individually Impaired Loans (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	$ 100,748	$ 104,310
Individually impaired loans with related allowance recorded: total recorded investment	96,256	99,481
Related allowance for loan losses	(12,335)	(13,295)
Individually impaired loans with no related allowance recorded: unpaid principal balance	19,706	19,689
Individually impaired loans with no related allowance recorded: total recorded investment	18,626	18,622
Total individually impaired loans: unpaid principal balance	120,454	123,999
Total individually impaired loans: total recorded investment	114,882	118,103
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	97,988	117,507
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	1,023	1,197
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method	95	128
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	18,545	19,140
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	270	319
Impaired Financing Receivable, with No Related Allowance, Interest Income, Cash Basis Method	31	31
Impaired Financing Receivable, Average Recorded Investment	116,533	136,647
Impaired Financing Receivable, Interest Income, Accrual Method	1,293	1,516
Impaired Financing Receivable, Interest Income, Cash Basis Method	126	159
Single-family [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	100,451	104,113
Individually impaired loans with related allowance recorded: total recorded investment	95,958	99,285
Related allowance for loan losses	(12,291)	(13,255)
Individually impaired loans with no related allowance recorded: unpaid principal balance	19,346	19,346
Individually impaired loans with no related allowance recorded: total recorded investment	18,265	18,276
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	97,741	117,249
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	1,021	1,197
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method	95	128
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	18,192	18,809
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	268	317
Impaired Financing Receivable, with No Related Allowance, Interest Income, Cash Basis Method	31	31
Single-family [Member] \| Primary [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	79,713	81,791
Individually impaired loans with related allowance recorded: total recorded investment	76,804	78,688
Related allowance for loan losses	(8,816)	(9,406)
Individually impaired loans with no related allowance recorded: unpaid principal balance	16,089	15,939
Individually impaired loans with no related allowance recorded: total recorded investment	15,325	15,191
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	77,842	88,411
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	817	911
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method	80	107
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	15,195	15,007
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	220	243
Impaired Financing Receivable, with No Related Allowance, Interest Income, Cash Basis Method	28	26
Single-family [Member] \| Government [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	265	264
Individually impaired loans with related allowance recorded: total recorded investment	270	270
Related allowance for loan losses	(55)	(55)
Individually impaired loans with no related allowance recorded: unpaid principal balance	61	61
Individually impaired loans with no related allowance recorded: total recorded investment	57	56
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	272	276
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	3	3
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method	0	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	56	60
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	1	0
Impaired Financing Receivable, with No Related Allowance, Interest Income, Cash Basis Method	0	0
Single-family [Member] \| Alt-A [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	15,486	16,576
Individually impaired loans with related allowance recorded: total recorded investment	14,178	15,158
Related allowance for loan losses	(2,526)	(2,793)
Individually impaired loans with no related allowance recorded: unpaid principal balance	2,508	2,628
Individually impaired loans with no related allowance recorded: total recorded investment	2,248	2,363
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	14,687	20,708
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	156	212
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method	11	16
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	2,293	2,842
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	39	58
Impaired Financing Receivable, with No Related Allowance, Interest Income, Cash Basis Method	2	4
Single-family [Member] \| Other [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	4,987	5,482
Individually impaired loans with related allowance recorded: total recorded investment	4,706	5,169
Related allowance for loan losses	(894)	(1,001)
Individually impaired loans with no related allowance recorded: unpaid principal balance	688	718
Individually impaired loans with no related allowance recorded: total recorded investment	635	666
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	4,940	7,854
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	45	71
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method	4	5
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	648	900
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	8	16
Impaired Financing Receivable, with No Related Allowance, Interest Income, Cash Basis Method	1	1
Multifamily [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: unpaid principal balance	297	197
Individually impaired loans with related allowance recorded: total recorded investment	298	196
Related allowance for loan losses	(44)	(40)
Individually impaired loans with no related allowance recorded: unpaid principal balance	360	343
Individually impaired loans with no related allowance recorded: total recorded investment	361	346
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	247	258
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	2	0
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method	0	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	353	331
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	2	2
Impaired Financing Receivable, with No Related Allowance, Interest Income, Cash Basis Method	$ 0	$ 0

Mortgage Loans Individually I_2

Mortgage Loans Individually Impaired Loans - 2 (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	$ 97,988	$ 117,507
Individually impaired loans with related allowance recorded: total interest income recognized	1,023	1,197
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	95	128
Individually impaired loans with no related allowance recorded: average recorded investment	18,545	19,140
Individually impaired loans with no related allowance recorded: total interest income recognized	270	319
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	31	31
Individually impaired loans: average recorded investment	116,533	136,647
Individually impaired loans: total interest income recognized	1,293	1,516
Individually impaired loans: interest income recognized on a cash basis	126	159
Table Footnote [Abstract]
Individually impaired loans: total interest income recognized	1,293	1,516
Single-family [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	97,741	117,249
Individually impaired loans with related allowance recorded: total interest income recognized	1,021	1,197
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	95	128
Individually impaired loans with no related allowance recorded: average recorded investment	18,192	18,809
Individually impaired loans with no related allowance recorded: total interest income recognized	268	317
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	31	31
Table Footnote [Abstract]
Troubled debt restructuring recorded investment	113,900	117,200
Single-family [Member] \| Primary [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	77,842	88,411
Individually impaired loans with related allowance recorded: total interest income recognized	817	911
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	80	107
Individually impaired loans with no related allowance recorded: average recorded investment	15,195	15,007
Individually impaired loans with no related allowance recorded: total interest income recognized	220	243
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	28	26
Single-family [Member] \| Government [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	272	276
Individually impaired loans with related allowance recorded: total interest income recognized	3	3
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	0	0
Individually impaired loans with no related allowance recorded: average recorded investment	56	60
Individually impaired loans with no related allowance recorded: total interest income recognized	1	0
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	0	0
Single-family [Member] \| Alt-A [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	14,687	20,708
Individually impaired loans with related allowance recorded: total interest income recognized	156	212
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	11	16
Individually impaired loans with no related allowance recorded: average recorded investment	2,293	2,842
Individually impaired loans with no related allowance recorded: total interest income recognized	39	58
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	2	4
Single-family [Member] \| Other [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	4,940	7,854
Individually impaired loans with related allowance recorded: total interest income recognized	45	71
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	4	5
Individually impaired loans with no related allowance recorded: average recorded investment	648	900
Individually impaired loans with no related allowance recorded: total interest income recognized	8	16
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	1	1
Multifamily [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	247	258
Individually impaired loans with related allowance recorded: total interest income recognized	2	0
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	0	0
Individually impaired loans with no related allowance recorded: average recorded investment	353	331
Individually impaired loans with no related allowance recorded: total interest income recognized	2	2
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	0	0
Table Footnote [Abstract]
Troubled debt restructuring recorded investment	$ 188	$ 187

Mortgage Loans TDRs (Details)

Mortgage Loans TDRs (Details) $ in Millions	3 Months Ended
Mortgage Loans TDRs (Details) $ in Millions	Mar. 31, 2019USD ($)contracts	Mar. 31, 2018USD ($)contracts
Financing Receivable, Modifications [Line Items]
Average term extension of a single-family modified loan	157 months	144 months
Average interest rate reduction of a single-family modified loan	0.10%	0.31%
Number of loans troubled debt restructurings activity \| contracts	13,896	44,362
Recorded investment troubled debt restructurings activity \| $	$ 2,112	$ 6,937
Single-family [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity \| contracts	13,893	44,354
Recorded investment troubled debt restructurings activity \| $	$ 2,099	$ 6,895
Single-family [Member] \| Primary [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity \| contracts	12,957	41,679
Recorded investment troubled debt restructurings activity \| $	$ 1,971	$ 6,524
Single-family [Member] \| Government [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity \| contracts	23	48
Recorded investment troubled debt restructurings activity \| $	$ 4	$ 4
Single-family [Member] \| Alt-A [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity \| contracts	766	2,182
Recorded investment troubled debt restructurings activity \| $	$ 97	$ 283
Single-family [Member] \| Other [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity \| contracts	147	445
Recorded investment troubled debt restructurings activity \| $	$ 27	$ 84
Multifamily [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity \| contracts	3	8
Recorded investment troubled debt restructurings activity \| $	$ 13	$ 42

Mortgage Loans TDRs with Sub De

Mortgage Loans TDRs with Sub Defaults (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)contracts	Mar. 31, 2018USD ($)contracts
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings subsequent default \| contracts	5,159	5,705
Recorded investment troubled debt restructurings subsequent default \| $	$ 777	$ 852
Single-family [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings subsequent default \| contracts	5,159	5,704
Recorded investment troubled debt restructurings subsequent default \| $	$ 777	$ 850
Single-family [Member] \| Primary [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings subsequent default \| contracts	4,516	4,818
Recorded investment troubled debt restructurings subsequent default \| $	$ 673	$ 701
Single-family [Member] \| Government [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings subsequent default \| contracts	18	14
Recorded investment troubled debt restructurings subsequent default \| $	$ 3	$ 2
Single-family [Member] \| Alt-A [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings subsequent default \| contracts	471	677
Recorded investment troubled debt restructurings subsequent default \| $	$ 73	$ 109
Single-family [Member] \| Other [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings subsequent default \| contracts	154	195
Recorded investment troubled debt restructurings subsequent default \| $	$ 28	$ 38
Multifamily [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings subsequent default \| contracts	0	1
Recorded investment troubled debt restructurings subsequent default \| $	$ 0	$ 2

Allowance for Loan Losses Rollf

Allowance for Loan Losses Rollforward by Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Allowance for Loan Losses [Roll Forward]
Beginning balance	$ (14,203)	$ (19,084)
Benefit (provision) for loan losses	634	(58)
Charge-offs	381	469
Recoveries	(45)	(60)
Other	1	(1)
Ending balance	(13,232)	(18,734)
Single-family [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	(13,969)	(18,849)
Benefit (provision) for loan losses	647	(78)
Charge-offs	381	465
Recoveries	(45)	(60)
Other	1	(1)
Ending balance	(12,985)	(18,523)
Multifamily [Member]
Allowance for Loan Losses [Roll Forward]
Beginning balance	(234)	(235)
Benefit (provision) for loan losses	(13)	20
Charge-offs	0	4
Ending balance	$ (247)	$ (211)

Allowance for Loan Losses and T

Allowance for Loan Losses and Total Recorded Investment in HFI Loans (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	$ (12,335)	$ (13,295)
Allowance for loan losses for collectively reserved loans	(897)	(908)
Total allowance for loan losses	(13,232)	(14,203)	$ (18,734)	$ (19,084)
Recorded investment in individually impaired loans	114,882	118,103
Recorded investment in collectively reserved loans	3,147,934	3,137,065
Total recorded investment in loans	3,262,816	3,255,168
Single-family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	(12,291)	(13,255)
Allowance for loan losses for collectively reserved loans	(694)	(714)
Total allowance for loan losses	(12,985)	(13,969)	(18,523)	(18,849)
Recorded investment in individually impaired loans	114,223	117,561
Recorded investment in collectively reserved loans	2,844,196	2,841,943
Total recorded investment in loans	2,958,419	2,959,504
Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses for individually impaired loans	(44)	(40)
Allowance for loan losses for collectively reserved loans	(203)	(194)
Total allowance for loan losses	(247)	(234)	$ (211)	$ (235)
Recorded investment in individually impaired loans	659	542
Recorded investment in collectively reserved loans	303,738	295,122
Total recorded investment in loans	$ 304,397	$ 295,664

Investments in Securities Tradi

Investments in Securities Trading 1 (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	$ 40,899	$ 41,867
Mortgage-related securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	5,795	6,276
Fannie Mae [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	1,583	1,467
Other agency [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	3,158	3,503
Alt-A and subprime private-label securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	1,054	1,306
Non-mortgage-related securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	35,104	35,591
U.S. Treasury securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	35,020	35,502
Other securities [Member]
Schedule of Investments in Trading Securities [Line Items]
Trading, at fair value	$ 84	$ 89

Investments in Securities Tra_2

Investments in Securities Trading 2 (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Debt and Equity Securities, FV-NI [Line Items]
Net trading gains	$ 92	$ 98
Net trading gains recognized in the period related to securities still held at period end	$ 89	$ 76

Investments in Securities Avail

Investments in Securities Available-for-sale Securities 1 (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Gross realized gains	$ 61	$ 363
Total proceeds (excludes initial sale of securities from new portfolio securitizations)	$ 131	$ 635

Investments in Securities Ava_2

Investments in Securities Available-for-sale Securities 2 (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Total amortized cost	$ 2,910	$ 3,079
Gross unrealized gains	327	380
Gross unrealized losses	(23)	(30)
Total fair value	3,214	3,429
Fannie Mae [Member]
Debt Securities, Available-for-sale [Line Items]
Total amortized cost	1,689	1,754
Gross unrealized gains	82	69
Gross unrealized losses	(19)	(26)
Total fair value	1,752	1,797
Other agency [Member]
Debt Securities, Available-for-sale [Line Items]
Total amortized cost	225	239
Gross unrealized gains	17	17
Gross unrealized losses	0	0
Total fair value	242	256
Alt-A and subprime private-label securities [Member]
Debt Securities, Available-for-sale [Line Items]
Total amortized cost	246	325
Gross unrealized gains	206	267
Gross unrealized losses	0	0
Total fair value	452	592
Mortgage revenue bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Total amortized cost	416	425
Gross unrealized gains	13	13
Gross unrealized losses	(4)	(4)
Total fair value	425	434
Other mortgage-related securities [Member]
Debt Securities, Available-for-sale [Line Items]
Total amortized cost	334	336
Gross unrealized gains	9	14
Gross unrealized losses	0	0
Total fair value	$ 343	$ 350

Investments in Securities Ava_3

Investments in Securities Available-for-sale Securities 3 (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Less than 12 Consecutive Months, Gross Unrealized Losses	$ (1)	$ (1)
Less than 12 Consecutive Months, Fair Value	15	24
12 Consecutive Months or Longer, Gross Unrealized Losses	(22)	(29)
12 Consecutive Months or Longer, Fair Value	375	506
Fannie Mae [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Consecutive Months, Gross Unrealized Losses	0	0
Less than 12 Consecutive Months, Fair Value	0	0
12 Consecutive Months or Longer, Gross Unrealized Losses	(19)	(26)
12 Consecutive Months or Longer, Fair Value	372	487
Mortgage revenue bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Consecutive Months, Gross Unrealized Losses	(1)	(1)
Less than 12 Consecutive Months, Fair Value	15	24
12 Consecutive Months or Longer, Gross Unrealized Losses	(3)	(3)
12 Consecutive Months or Longer, Fair Value	$ 3	$ 19

Investments in Securities Other

Investments in Securities Other-than-temporary Impairments (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Available-for-sale securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Balance of the unrealized credit loss component of AFS debt securities held by us	$ 323	$ 635	$ 729	$ 1,100

Investments in Securities Matur

Investments in Securities Maturity Information (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	$ 2,910	$ 3,079
Total fair value	3,214	3,429
One Year or Less, Amortized Cost	2
One Year or Less, Fair Value	2
After One Year through Five Years, Amortized Cost	67
After One Year through Five Years, Fair Value	69
After Five Years through Ten Years, Amortized Cost	224
After Five Years through Ten Years, Fair Value	242
After Ten Years, Amortized Cost	2,617
After Ten Years, Fair Value	2,901
Fannie Mae [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	1,689	1,754
Total fair value	1,752	1,797
One Year or Less, Amortized Cost	0
One Year or Less, Fair Value	0
After One Year through Five Years, Amortized Cost	14
After One Year through Five Years, Fair Value	15
After Five Years through Ten Years, Amortized Cost	114
After Five Years through Ten Years, Fair Value	124
After Ten Years, Amortized Cost	1,561
After Ten Years, Fair Value	1,613
Other agency [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	225	239
Total fair value	242	256
One Year or Less, Amortized Cost	0
One Year or Less, Fair Value	0
After One Year through Five Years, Amortized Cost	23
After One Year through Five Years, Fair Value	24
After Five Years through Ten Years, Amortized Cost	29
After Five Years through Ten Years, Fair Value	32
After Ten Years, Amortized Cost	173
After Ten Years, Fair Value	186
Alt-A and subprime private-label securities [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	246	325
Total fair value	452	592
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	1
After Five Years through Ten Years, Fair Value	1
After Ten Years, Amortized Cost	245
After Ten Years, Fair Value	451
Mortgage revenue bonds [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	416	425
Total fair value	425	434
One Year or Less, Amortized Cost	2
One Year or Less, Fair Value	2
After One Year through Five Years, Amortized Cost	30
After One Year through Five Years, Fair Value	30
After Five Years through Ten Years, Amortized Cost	52
After Five Years through Ten Years, Fair Value	54
After Ten Years, Amortized Cost	332
After Ten Years, Fair Value	339
Other mortgage-related securities [Member]
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Rolling Maturity
Total amortized cost	334	336
Total fair value	343	$ 350
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	28
After Five Years through Ten Years, Fair Value	31
After Ten Years, Amortized Cost	306
After Ten Years, Fair Value	$ 312

Financial Guarantees Financial

Financial Guarantees Financial Guarantees and Maximum Recovery (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Financial Guarantees and Maximum Recovery [Line Items]
Maximum Exposure	$ 20,728	$ 21,125
Guaranty Obligation	170	160
Maximum Recovery	9,408	9,522
Unconsolidated VIEs [Member] \| Unconsolidated Fannie Mae MBS [Member]
Financial Guarantees and Maximum Recovery [Line Items]
Maximum Exposure	7,102	7,278
Guaranty Obligation	29	30
Maximum Recovery	6,699	6,811
Unconsolidated VIEs [Member] \| Other guaranty arrangements [Member]
Financial Guarantees and Maximum Recovery [Line Items]
Maximum Exposure	13,626	13,847
Guaranty Obligation	141	130
Maximum Recovery	$ 2,709	$ 2,711
Minimum [Member]
Financial Guarantees and Maximum Recovery [Line Items]
Contractual terms of our guarantees	1 day
Maximum [Member]
Financial Guarantees and Maximum Recovery [Line Items]
Contractual terms of our guarantees	34 years

Short-Term and Long-Term Debt S

Short-Term and Long-Term Debt Short-Term Debt (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Intraday line of credit [Member]
Short-Term Debt [Line Items]
Line of credit maximum borrowing capacity	$ 15,000	$ 15,000
Fannie Mae [Member]
Short-Term Debt [Line Items]
Short-term debt, outstanding	$ 23,071	$ 24,896
Short-term debt, weighted-average interest rate	2.33%	2.29%

Short-Term and Long-Term Debt L

Short-Term and Long-Term Debt Long-Term Debt (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 3,371,939	$ 3,367,024
Long-term debt, weighted-average interest rate	3.06%	3.02%
Consolidated Trusts [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 3,173,772	$ 3,159,846
Long-term debt, weighted-average interest rate	3.06%	3.03%
Fannie Mae [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 198,167	$ 207,178
Long-term debt, weighted-average interest rate	2.93%	2.83%
Unamortized discounts and premiums, other cost basis adjustments and fair value adjustments	$ 213	$ 413
Fannie Mae [Member] \| Minimum [Member]
Long-Term Debt [Line Items]
Medium-term notes original contractual maturity	1 year
Long-term debt original contractual maturity greater than 10 years	10 years
Fannie Mae [Member] \| Maximum [Member]
Long-Term Debt [Line Items]
Medium-term notes original contractual maturity	10 years
Fannie Mae [Member] \| Senior Fixed [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 161,605	$ 171,344
Long-term debt, weighted-average interest rate	2.20%	2.13%
Fannie Mae [Member] \| Senior fixed benchmark notes and bonds [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 97,710	$ 103,206
Long-term debt, weighted-average interest rate	2.46%	2.36%
Fannie Mae [Member] \| Senior fixed medium-term notes [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 57,220	$ 61,455
Long-term debt, weighted-average interest rate	1.48%	1.48%
Fannie Mae [Member] \| Senior fixed other debt [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 6,675	$ 6,683
Long-term debt, weighted-average interest rate	4.61%	4.62%
Fannie Mae [Member] \| Senior floating [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 31,014	$ 30,166
Long-term debt, weighted-average interest rate	5.50%	5.52%
Fannie Mae [Member] \| Senior floating medium-term notes [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 5,574	$ 4,174
Long-term debt, weighted-average interest rate	2.47%	2.36%
Fannie Mae [Member] \| Senior floating Connecticut Avenue Securities [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 25,064	$ 25,641
Long-term debt, weighted-average interest rate	6.13%	5.97%
Fannie Mae [Member] \| Senior floating other debt [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 376	$ 351
Long-term debt, weighted-average interest rate	7.85%	10.19%
Fannie Mae [Member] \| Subordinated debentures [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 5,502	$ 5,617
Long-term debt, weighted-average interest rate	9.67%	9.64%
Fannie Mae [Member] \| Secured borrowings [Member]
Long-Term Debt [Line Items]
Long-term debt, outstanding	$ 46	$ 51
Long-term debt, weighted-average interest rate	2.06%	1.96%

Derivative Instruments Derivati

Derivative Instruments Derivatives 1 - Notional and FV Position (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Asset Derivatives [Abstract]
Notional amount	$ 289,006	$ 266,935
Derivative asset, estimated fair value	584	458
Netting adjustment	(1,781)	(2,266)
Liability Derivatives [Abstract]
Notional amount	189,016	161,488
Derivative liability, estimated fair value	(793)	(777)
Netting adjustment	2,126	2,315
Table Footnote [Abstract]
Cash collateral posted for derivative instruments	882	713
Cash collateral received for derivative instruments	537	664
Pay-fixed Swap
Asset Derivatives [Abstract]
Notional amount	70,599	71,416
Derivative asset, estimated fair value	171	438
Liability Derivatives [Abstract]
Notional amount	22,538	21,253
Derivative liability, estimated fair value	(823)	(740)
Receive-fixed Swap
Asset Derivatives [Abstract]
Notional amount	89,157	88,799
Derivative asset, estimated fair value	1,037	1,113
Liability Derivatives [Abstract]
Notional amount	53,059	58,399
Derivative liability, estimated fair value	(541)	(860)
Basis Swap
Asset Derivatives [Abstract]
Notional amount	273	250
Derivative asset, estimated fair value	129	104
Liability Derivatives [Abstract]
Notional amount	0	624
Derivative liability, estimated fair value	0	0
Foreign Currency Swap
Asset Derivatives [Abstract]
Notional amount	226	221
Derivative asset, estimated fair value	35	22
Liability Derivatives [Abstract]
Notional amount	228	223
Derivative liability, estimated fair value	(66)	(72)
Pay-fixed Swaption
Asset Derivatives [Abstract]
Notional amount	5,350	10,375
Derivative asset, estimated fair value	46	191
Liability Derivatives [Abstract]
Notional amount	5,625	1,000
Derivative liability, estimated fair value	(45)	(4)
Receive-fixed Swaption
Asset Derivatives [Abstract]
Notional amount	1,100	500
Derivative asset, estimated fair value	51	20
Liability Derivatives [Abstract]
Notional amount	6,375	7,375
Derivative liability, estimated fair value	(287)	(338)
Future [Member]
Asset Derivatives [Abstract]
Notional amount	21,594	16,631
Derivative asset, estimated fair value	0	0
Liability Derivatives [Abstract]
Notional amount	0	0
Derivative liability, estimated fair value	0	0
Risk Management Derivatives
Asset Derivatives [Abstract]
Notional amount	188,299	188,192
Derivative asset, estimated fair value	1,469	1,888
Accrued interest receivable (payable)	395	400
Netting adjustment	(1,781)	(2,266)
Total net risk management derivatives	83	22
Liability Derivatives [Abstract]
Notional amount	87,825	88,874
Derivative liability, estimated fair value	(1,762)	(2,014)
Accrued interest receivable (payable)	(462)	(419)
Netting adjustment	2,126	2,315
Total net risk management derivatives	(98)	(118)
Mortgage commitments to purchase whole loans
Asset Derivatives [Abstract]
Notional amount	3,901	4,370
Derivative asset, estimated fair value	26	29
Liability Derivatives [Abstract]
Notional amount	2,153	57
Derivative liability, estimated fair value	(3)	0
Forward contracts to purchase mortgage-related securities
Asset Derivatives [Abstract]
Notional amount	53,514	40,650
Derivative asset, estimated fair value	403	349
Liability Derivatives [Abstract]
Notional amount	9,649	1,045
Derivative liability, estimated fair value	(10)	(3)
Forward contracts to sell mortgage-related securities
Asset Derivatives [Abstract]
Notional amount	10,547	292
Derivative asset, estimated fair value	10	1
Liability Derivatives [Abstract]
Notional amount	86,515	70,593
Derivative liability, estimated fair value	(653)	(645)
Mortgage commitment derivatives
Asset Derivatives [Abstract]
Notional amount	67,962	45,312
Derivative asset, estimated fair value	439	379
Netting adjustment	0	0
Liability Derivatives [Abstract]
Notional amount	98,317	71,695
Derivative liability, estimated fair value	(666)	(648)
Netting adjustment	0	0
Other
Asset Derivatives [Abstract]
Notional amount	32,745	33,431
Derivative asset, estimated fair value	62	57
Liability Derivatives [Abstract]
Notional amount	2,874	919
Derivative liability, estimated fair value	$ (29)	$ (11)

Derivative Instruments Deriva_2

Derivative Instruments Derivatives 2 - FV Gains and Losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	$ (695)	$ 863
Net accrual of periodic settlements	4,733	5,232
Pay-fixed Swap
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	(1,335)	2,783
Receive-fixed Swap
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	1,281	(2,387)
Basis Swap
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	24	(23)
Foreign Currency Swap
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	19	16
Pay-fixed Swaption
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	(177)	129
Receive-fixed Swaption
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	7	(16)
Future [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	59	8
Risk Management Derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	(388)	295
Net accrual of periodic settlements	(266)	(215)
Mortgage commitment derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	(300)	564
Other
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	$ (7)	$ 4

Segment Reporting Narrative (De

Segment Reporting Narrative (Details)	3 Months Ended
Segment Reporting Narrative (Details)	Mar. 31, 2019segments
Segment Reporting [Abstract]
Number of Reportable Segments	2

Segment Reporting (Details)

Segment Reporting (Details) - USD ($) $ in Millions	3 Months Ended
Segment Reporting (Details) - USD ($) $ in Millions	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Net interest income	$ 4,733	$ 5,232
Fee and other income	227	320
Net revenues	4,960	5,552
Investment gains (losses), net	133	250
Fair value gains (losses), net	(831)	1,045
Administrative expenses	(744)	(750)
Benefit (provision) for credit losses	650	217
Foreclosed property income (expense)	(140)	(162)
Total credit-related income (expense)	510	55
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees	(593)	(557)
Other expenses, net	(408)	(203)
Income before federal income taxes	3,027	5,392
Provision for federal income taxes	(627)	(1,131)
Net income	2,400	4,261
US Treasury [Member]
Segment Reporting Information [Line Items]
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees	(593)	(557)
Business Segments [Member] \| Single-family [Member]
Segment Reporting Information [Line Items]
Net interest income	4,039	4,561
Fee and other income	106	158
Net revenues	4,145	4,719
Investment gains (losses), net	94	242
Fair value gains (losses), net	(887)	1,034
Administrative expenses	(631)	(643)
Benefit (provision) for credit losses	661	196
Foreclosed property income (expense)	(143)	(162)
Total credit-related income (expense)	518	34
Other expenses, net	(337)	132
Income before federal income taxes	2,309	4,697
Provision for federal income taxes	(484)	(1,016)
Net income	1,825	3,681
Business Segments [Member] \| Single-family [Member] \| US Treasury [Member]
Segment Reporting Information [Line Items]
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees	(593)	(557)
Business Segments [Member] \| Multifamily [Member]
Segment Reporting Information [Line Items]
Net interest income	694	671
Fee and other income	121	162
Net revenues	815	833
Investment gains (losses), net	39	8
Fair value gains (losses), net	56	11
Administrative expenses	(113)	(107)
Benefit (provision) for credit losses	(11)	21
Foreclosed property income (expense)	3	0
Total credit-related income (expense)	(8)	21
Other expenses, net	(71)	(71)
Income before federal income taxes	718	695
Provision for federal income taxes	(143)	(115)
Net income	575	580
Business Segments [Member] \| Multifamily [Member] \| US Treasury [Member]
Segment Reporting Information [Line Items]
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees	$ 0	$ 0

Equity AOCI (Details)

Equity AOCI (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Equity [Abstract]
Net unrealized gains on AFS securities for which we have not recorded OTTI	$ 67	$ 52
Net unrealized gains on AFS securities for which we have recorded OTTI	173	224
Other	43	46
Accumulated other comprehensive income	$ 283	$ 322

Equity Changes in AOCI (Details

Equity Changes in AOCI (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
Equity Changes in AOCI (Details) - USD ($) $ in Millions	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	$ 6,240
Total other comprehensive loss	(39)	$ (323)
Ending balance	$ 5,361		$ 6,240
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%		35.00%
Accumulated net unrealized investment gain (loss), AFS securities [Member]
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	$ 276	510	$ 510
Reclassification of accumulated other comprehensive income to retained earnings resulting from the enactment of the Tax Cuts and Jobs Act	0	110
Other comprehensive income (loss) before reclassifications	8	(57)
Amounts reclassified from other comprehensive loss	(44)	(263)
Total other comprehensive loss	(36)	(320)
Ending balance	240	300	276
Accumulated other comprehensive income (loss), Other [Member]
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	46	43	43
Reclassification of accumulated other comprehensive income to retained earnings resulting from the enactment of the Tax Cuts and Jobs Act	0	7
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified from other comprehensive loss	(3)	(3)
Total other comprehensive loss	(3)	(3)
Ending balance	43	47	46
Accumulated Other Comprehensive Income
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	322	553	553
Reclassification of accumulated other comprehensive income to retained earnings resulting from the enactment of the Tax Cuts and Jobs Act	0	117
Other comprehensive income (loss) before reclassifications	8	(57)
Amounts reclassified from other comprehensive loss	(47)	(266)
Total other comprehensive loss	(39)	(323)
Ending balance	$ 283	$ 347	$ 322

Concentrations of Credit Risk S

Concentrations of Credit Risk SF Risk Characteristics (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Multifamily [Member] \| Guaranty Book of Business [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30 days delinquent (percentage of book of business)		0.02%
Seriously delinquent (percentage of book of business)	0.07%	0.06%
Multifamily [Member] \| Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Serious delinquency, days past due	60 days	60 days
Multifamily [Member] \| Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Serious delinquency, days past due	89 days	89 days
Single-family [Member] \| Guaranty Book of Business [Member] \| Conventional Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	99.00%
30 days delinquent (percentage of book of business)	1.15%	1.17%
60 days delinquent (percentage of book of business)	0.31%	0.32%
Seriously delinquent (percentage of book of business)	0.67%	0.69%
30 days delinquent (percentage of conventional loans)	1.32%	1.37%
60 days delinquent (percentage of conventional loans)	0.35%	0.38%
Seriously delinquent (percentage of conventional loans)	0.74%	0.76%
Percentage of loans with detailed loan level information		99.00%
Single-family [Member] \| Guaranty Book of Business [Member] \| Conventional Loan [Member] \| California
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	19.00%	19.00%
Seriously delinquent (percentage of conventional loans)	0.34%	0.34%
Single-family [Member] \| Guaranty Book of Business [Member] \| Conventional Loan [Member] \| Florida
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	6.00%	6.00%
Seriously delinquent (percentage of conventional loans)	1.03%	1.16%
Single-family [Member] \| Guaranty Book of Business [Member] \| Conventional Loan [Member] \| New Jersey
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	3.00%	4.00%
Seriously delinquent (percentage of conventional loans)	1.32%	1.38%
Single-family [Member] \| Guaranty Book of Business [Member] \| Conventional Loan [Member] \| New York
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	5.00%	5.00%
Seriously delinquent (percentage of conventional loans)	1.38%	1.40%
Single-family [Member] \| Guaranty Book of Business [Member] \| Conventional Loan [Member] \| All other states
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	67.00%	66.00%
Seriously delinquent (percentage of conventional loans)	0.72%	0.75%
Single-family [Member] \| Guaranty Book of Business [Member] \| Conventional Loan [Member] \| Estimated mark-to-market loan-to-value ratio greater than 100%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Seriously delinquent (percentage of conventional loans)	9.35%	9.85%
Single-family [Member] \| Guaranty Book of Business [Member] \| Conventional Loan [Member] \| Alt-A [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	2.00%	2.00%
Seriously delinquent (percentage of conventional loans)	3.31%	3.35%
Single-family [Member] \| Guaranty Book of Business [Member] \| Conventional Loan [Member] \| 2004 and prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	3.00%	3.00%
Seriously delinquent (percentage of conventional loans)	2.68%	2.69%
Single-family [Member] \| Guaranty Book of Business [Member] \| Conventional Loan [Member] \| 2005-2008
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	4.00%	5.00%
Seriously delinquent (percentage of conventional loans)	4.50%	4.61%
Single-family [Member] \| Guaranty Book of Business [Member] \| Conventional Loan [Member] \| 2009-2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	93.00%	92.00%
Seriously delinquent (percentage of conventional loans)	0.33%	0.34%
Single-family [Member] \| Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Serious delinquency, days past due	90 days	90 days

Concentrations of Credit Risk M

Concentrations of Credit Risk MF Risk Characteristics (Details) - Multifamily [Member]	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Serious delinquency, days past due	60 days	60 days
Current debt service coverage ratio reporting lag	3 months	3 months
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current debt service coverage ratio (higher risk loans)	1	1
Serious delinquency, days past due	89 days	89 days
Current debt service coverage ratio reporting lag	6 months	6 months
Guaranty Book of Business [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30 days delinquent (percentage of book of business)		0.02%
Seriously delinquent (percentage of book of business)	0.07%	0.06%
Guaranty Book of Business [Member] \| Original LTV ratio greater than 80% [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	1.00%	1.00%
Loans seriously delinquent, percentage by unpaid principal balance	0.00%	0.00%
Guaranty Book of Business [Member] \| Original LTV ratio less than or equal to 80% [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	99.00%	99.00%
Loans seriously delinquent, percentage by unpaid principal balance	0.07%	0.06%
Guaranty Book of Business [Member] \| Current DSCR less than 100% [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of book of business	2.00%	2.00%
Loans seriously delinquent, percentage by unpaid principal balance	0.62%	1.38%

Concentrations of Credit Risk O

Concentrations of Credit Risk Other Concentrations (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Concentration Risk [Line Items]
Estimated benefit included in total loss reserves	$ 665	$ 691
Receivable from claims on insured, defaulted loans excluding government insured loans	699	745
Allowance for mortgage insurance receivable	$ 544	564
PMI Mortgage Insurance Company [Member]
Concentration Risk [Line Items]
Mortgage insurance coverage risk in force percentage to be paid in cash	74.50%
Mortgage insurance coverage risk in force percentage to be deferred	25.50%
Triad Guaranty Insurance Corporation 1 [Member]
Concentration Risk [Line Items]
Mortgage insurance coverage risk in force percentage to be paid in cash	75.00%
Mortgage insurance coverage risk in force percentage to be deferred	25.00%
Single-family [Member] \| Guaranty Book of Business [Member]
Concentration Risk [Line Items]
Mortgage insurance coverage risk in force	$ 155,223	$ 152,788
Mortgage insurance coverage risk in force as percentage	5.00%	5.00%
Primary mortgage insurance coverage risk in force	$ 154,823	$ 152,379
Pool mortgage insurance coverage risk in force	$ 400	$ 409
Single-family [Member] \| Guaranty Book of Business [Member] \| Credit Concentration Risk [Member] \| Group of Largest Mortgage Servicers including Affiliates [Member]
Concentration Risk [Line Items]
Percentage of Risk in Force Coverage by Mortgage Insurer	58.00%	56.00%
Single-family [Member] \| Guaranty Book of Business [Member] \| Credit Concentration Risk [Member] \| Group of Largest Mortgage Servicers including Affiliates [Member] \| Non-Depository Servicer [Member]
Concentration Risk [Line Items]
Percentage of Risk in Force Coverage by Mortgage Insurer	25.00%	22.00%
Single-family [Member] \| Guaranty Book of Business [Member] \| Credit Concentration Risk [Member] \| Wells Fargo Bank N.A. [Member] \| Depository Servicer [Member]
Concentration Risk [Line Items]
Percentage of Risk in Force Coverage by Mortgage Insurer	18.00%	18.00%
Single-family [Member] \| Guaranty Book of Business [Member] \| Credit Concentration Risk [Member] \| Other Servicers [Member] \| Depository Servicer [Member]
Concentration Risk [Line Items]
Percentage of Risk in Force Coverage by Mortgage Insurer	15.00%	16.00%
Single-family [Member] \| Guaranty Book of Business [Member] \| Insurance Service Provider Concentration Risk [Member]
Concentration Risk [Line Items]
Percentage of Risk in Force Coverage by Mortgage Insurer	100.00%	100.00%
Mortgage insurance coverage risk in force for insurers with credit quality deterioration	$ 4,400
Percentage of Concentration Risk	3.00%
Single-family [Member] \| Guaranty Book of Business [Member] \| Insurance Service Provider Concentration Risk [Member] \| Arch Capital Group Ltd. [Member]
Concentration Risk [Line Items]
Percentage of Risk in Force Coverage by Mortgage Insurer	24.00%	25.00%
Single-family [Member] \| Guaranty Book of Business [Member] \| Insurance Service Provider Concentration Risk [Member] \| Radian Guaranty, Inc [Member]
Concentration Risk [Line Items]
Percentage of Risk in Force Coverage by Mortgage Insurer	21.00%	21.00%
Single-family [Member] \| Guaranty Book of Business [Member] \| Insurance Service Provider Concentration Risk [Member] \| Mortgage Guaranty Insurance Corp. [Member]
Concentration Risk [Line Items]
Percentage of Risk in Force Coverage by Mortgage Insurer	18.00%	18.00%
Single-family [Member] \| Guaranty Book of Business [Member] \| Insurance Service Provider Concentration Risk [Member] \| Genworth Mortgage Insurance Corp. [Member]
Concentration Risk [Line Items]
Percentage of Risk in Force Coverage by Mortgage Insurer	15.00%	15.00%
Single-family [Member] \| Guaranty Book of Business [Member] \| Insurance Service Provider Concentration Risk [Member] \| Essent Guaranty, Inc [Member]
Concentration Risk [Line Items]
Percentage of Risk in Force Coverage by Mortgage Insurer	12.00%	12.00%
Single-family [Member] \| Guaranty Book of Business [Member] \| Insurance Service Provider Concentration Risk [Member] \| Other counterparties [Member]
Concentration Risk [Line Items]
Percentage of Risk in Force Coverage by Mortgage Insurer	10.00%	9.00%
Multifamily [Member] \| Guaranty Book of Business [Member] \| Credit Concentration Risk [Member] \| Group of Largest Mortgage Servicers including Affiliates [Member]
Concentration Risk [Line Items]
Percentage of Risk in Force Coverage by Mortgage Insurer	48.00%	48.00%
Multifamily [Member] \| Guaranty Book of Business [Member] \| Credit Concentration Risk [Member] \| Wells Fargo Bank N.A. [Member]
Concentration Risk [Line Items]
Percentage of Risk in Force Coverage by Mortgage Insurer	14.00%	14.00%
Multifamily [Member] \| Guaranty Book of Business [Member] \| Credit Concentration Risk [Member] \| Walker & Dunlop, LLC [Member]
Concentration Risk [Line Items]
Percentage of Risk in Force Coverage by Mortgage Insurer	12.00%	12.00%
Multifamily [Member] \| Guaranty Book of Business [Member] \| Credit Concentration Risk [Member] \| Other Servicers [Member]
Concentration Risk [Line Items]
Percentage of Risk in Force Coverage by Mortgage Insurer	22.00%	22.00%

Netting Arrangements (Details)

Netting Arrangements (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Offsetting Assets [Line Items]
Fair Value of Securities Received as Collateral that Have Been Resold or Repledged	$ 0	$ 0
Derivative Liability, Not Subject to Master Netting Arrangement	29	11
Assets:
Derivative assets, gross amount	2,303	2,667
Derivative assets, gross amount offset	(1,781)	(2,266)
Derivative assets, net amount presented in our condensed consolidated balance sheets	522	401
Derivative assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	(223)	(153)
Derivative assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	(14)	(7)
Derivative assets, net amount	285	241
Securities purchased under agreements to resell or similar arrangements, gross amount	39,850	48,288
Securities purchased under agreements to resell or similar arrangements, gross amount offset	0	0
Securities Purchased under Agreements to Resell, Not Subject to Master Netting Arrangement	39,850	48,288
Securities purchased under agreements to resell or similar arrangements, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	0	0
Securities purchased under agreements to resell or similar arrangements, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	(39,850)	(48,288)
Securities purchased under agreements to resell or similar arrangements, net amount	0	0
Total assets, gross amount	42,153	50,955
Total assets, gross amount offset	(1,781)	(2,266)
Total assets, net amount presented in our condensed consolidated balance sheets	40,372	48,689
Total assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	(223)	(153)
Total assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	(39,864)	(48,295)
Total assets, net amount	285	241
Liabilities:
Derivative liabilities, gross amount	(2,890)	(3,081)
Derivative liabilities, gross amount offset	2,126	2,315
Derivative liabilities, net amount presented in our condensed consolidated balance sheets	(764)	(766)
Derivative liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	223	153
Derivative liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	426	489
Derivative liabilities, net amount	(115)	(124)
Total liabilities, gross amount	(2,890)	(3,081)
Total liabilities, gross amount offset	2,126	2,315
Total liabilities, net amount presented in our condensed consolidated balance sheets	(764)	(766)
Total liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	223	153
Total liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	426	489
Total liabilities, net amount	(115)	(124)
Fair Value of Securities Received as Collateral that Can be Resold or Repledged	33,900	45,700
Risk Management Derivatives
Assets:
Derivative assets, gross amount offset	(1,781)	(2,266)
Liabilities:
Derivative liabilities, gross amount offset	2,126	2,315
Mortgage commitment derivatives
Assets:
Derivative assets, gross amount	439	379
Derivative assets, gross amount offset	0	0
Derivative assets, net amount presented in our condensed consolidated balance sheets	439	379
Derivative assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	(223)	(153)
Derivative assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	(14)	(7)
Derivative assets, net amount	202	219
Liabilities:
Derivative liabilities, gross amount	(666)	(648)
Derivative liabilities, gross amount offset	0	0
Derivative liabilities, net amount presented in our condensed consolidated balance sheets	(666)	(648)
Derivative liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	223	153
Derivative liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	416	466
Derivative liabilities, net amount	(27)	(29)
Over the Counter [Member] \| Risk Management Derivatives
Assets:
Derivative assets, gross amount	1,864	2,288
Derivative assets, gross amount offset	(1,801)	(2,273)
Derivative assets, net amount presented in our condensed consolidated balance sheets	63	15
Derivative assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	0	0
Derivative assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	0	0
Derivative assets, net amount	63	15
Liabilities:
Derivative liabilities, gross amount	(2,224)	(2,433)
Derivative liabilities, gross amount offset	2,143	2,342
Derivative liabilities, net amount presented in our condensed consolidated balance sheets	(81)	(91)
Derivative liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	0	0
Derivative liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	0	0
Derivative liabilities, net amount	(81)	(91)
Exchange Cleared [Member] \| Risk Management Derivatives
Assets:
Derivative assets, gross amount	0	0
Derivative assets, gross amount offset	20	7
Derivative assets, net amount presented in our condensed consolidated balance sheets	20	7
Derivative assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	0	0
Derivative assets, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	0	0
Derivative assets, net amount	20	7
Liabilities:
Derivative liabilities, gross amount	0	0
Derivative liabilities, gross amount offset	(17)	(27)
Derivative liabilities, net amount presented in our condensed consolidated balance sheets	(17)	(27)
Derivative liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, financial instruments	0	0
Derivative liabilities, under master netting arrangements, amounts not offset in our condensed consolidated balance sheets, collateral	10	23
Derivative liabilities, net amount	$ (7)	$ (4)

Netting Arrangements Narratives

Netting Arrangements Narratives (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Fair value of non-cash collateral we pledged	$ 1,800	$ 1,900
Fair value of non-cash collateral received	39,900	48,400
Fair value of non-cash collateral received that can be resold or repledged	33,900	45,700
Fair value of securities received as collateral that have been resold or repledge	0	0
Derivative assets not subject to enforceable master netting arrangements	62	57
Derivative liabilities not subject to enforceable master netting arrangements	(29)	(11)
Cash and Cash Equivalents [Member]
Derivative [Line Items]
Securities purchased under agreements to resell	$ 17,600	$ 15,400

Fair Value Levels Hierarchy (De

Fair Value Levels Hierarchy (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Assets [Abstract]
Mortgage loans held for investment, at fair value	$ 8,752	$ 8,922
Other assets [Abstract]
Derivative assets, gross amount offset	(1,781)	(2,266)
Other liabilities [Abstract]
Derivative liabilities, gross amount offset	(2,126)	(2,315)
Mortgage commitment derivatives
Other assets [Abstract]
Derivative assets, gross amount offset	0	0
Other liabilities [Abstract]
Derivative liabilities, gross amount offset	0	0
Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	6,682	6,826
Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	23,050	23,753
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets [Abstract]
Trading securities	35,020	35,502
Available-for-sale securities	0	0
Mortgage loans held for investment, at fair value	0	0
Other assets [Abstract]
Derivatives assets at fair value	0	0
Total assets at fair value	69,661	69,575
Other liabilities [Abstract]
Derivative liabilities at fair value	0	0
Total liabilities at fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	0	0
Significant Other Observable Inputs (Level 2) [Member]
Assets [Abstract]
Trading securities	5,812	6,332
Available-for-sale securities	2,230	2,477
Mortgage loans held for investment, at fair value	2,982,238	2,990,104
Other assets [Abstract]
Derivatives assets at fair value	2,129	2,515
Total assets at fair value	3,039,232	3,053,308
Other liabilities [Abstract]
Derivative liabilities at fair value	2,886	3,077
Total liabilities at fair value	3,348,843	3,303,620
Significant Other Observable Inputs (Level 2) [Member] \| Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	204,060	211,403
Significant Other Observable Inputs (Level 2) [Member] \| Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	3,118,819	3,064,239
Significant Unobservable Inputs (Level 3) [Member]
Assets [Abstract]
Trading securities	67	33
Available-for-sale securities	984	952
Mortgage loans held for investment, at fair value	275,207	216,404
Other assets [Abstract]
Derivatives assets at fair value	236	209
Total assets at fair value	284,797	225,812
Other liabilities [Abstract]
Derivative liabilities at fair value	33	15
Total liabilities at fair value	44,158	39,950
Significant Unobservable Inputs (Level 3) [Member] \| Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	813	771
Significant Unobservable Inputs (Level 3) [Member] \| Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	43,205	39,043
Recurring Fair Value Measurements [Member]
Assets [Abstract]
Cash equivalents		748
Trading securities	40,899	41,867
Available-for-sale securities	3,214	3,429
Mortgage loans held for investment, at fair value	8,752	8,922
Other assets [Abstract]
Derivatives assets at fair value	584	458
Derivative assets, gross amount offset	(1,781)	(2,266)
Total assets at fair value	53,449	55,424
Liabilities [Abstract]
Long-term debt, fair value	29,732	30,579
Other liabilities [Abstract]
Derivative liabilities at fair value	793	777
Derivative liabilities, gross amount offset	(2,126)	(2,315)
Total liabilities at fair value	30,525	31,356
Recurring Fair Value Measurements [Member] \| Swaps [Member]
Other assets [Abstract]
Derivatives assets at fair value	1,767	2,077
Other liabilities [Abstract]
Derivative liabilities at fair value	1,892	2,091
Recurring Fair Value Measurements [Member] \| Swaptions [Member]
Other assets [Abstract]
Derivatives assets at fair value	97	211
Other liabilities [Abstract]
Derivative liabilities at fair value	332	342
Recurring Fair Value Measurements [Member] \| Mortgage commitment derivatives
Other assets [Abstract]
Derivatives assets at fair value	439	379
Other liabilities [Abstract]
Derivative liabilities at fair value	666	648
Recurring Fair Value Measurements [Member] \| Other [Member]
Other assets [Abstract]
Derivatives assets at fair value	62	57
Other liabilities [Abstract]
Derivative liabilities at fair value	29	11
Recurring Fair Value Measurements [Member] \| Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	6,682	6,826
Recurring Fair Value Measurements [Member] \| Fannie Mae [Member] \| Senior floating [Member]
Liabilities [Abstract]
Long-term debt, fair value	6,682	6,826
Recurring Fair Value Measurements [Member] \| Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	23,050	23,753
Recurring Fair Value Measurements [Member] \| Fannie Mae [Member]
Assets [Abstract]
Trading securities	1,583	1,467
Available-for-sale securities	1,752	1,797
Recurring Fair Value Measurements [Member] \| Other agency [Member]
Assets [Abstract]
Trading securities	3,158	3,503
Available-for-sale securities	242	256
Recurring Fair Value Measurements [Member] \| Alt-A and subprime private-label securities [Member]
Assets [Abstract]
Trading securities	1,054	1,306
Available-for-sale securities	452	592
Recurring Fair Value Measurements [Member] \| Mortgage revenue bonds [Member]
Assets [Abstract]
Available-for-sale securities	425	434
Recurring Fair Value Measurements [Member] \| Other [Member]
Assets [Abstract]
Available-for-sale securities	343	350
Recurring Fair Value Measurements [Member] \| U.S. Treasury securities [Member]
Assets [Abstract]
Trading securities	35,020	35,502
Recurring Fair Value Measurements [Member] \| Other securities [Member]
Assets [Abstract]
Trading securities	84	89
Recurring Fair Value Measurements [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets [Abstract]
Cash equivalents		748
Trading securities	35,020	35,502
Available-for-sale securities	0	0
Mortgage loans held for investment, at fair value	0	0
Other assets [Abstract]
Derivatives assets at fair value	0	0
Total assets at fair value	35,020	36,250
Liabilities [Abstract]
Long-term debt, fair value	0	0
Other liabilities [Abstract]
Derivative liabilities at fair value	0	0
Total liabilities at fair value	0	0
Recurring Fair Value Measurements [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Swaps [Member]
Other assets [Abstract]
Derivatives assets at fair value	0	0
Other liabilities [Abstract]
Derivative liabilities at fair value	0	0
Recurring Fair Value Measurements [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Swaptions [Member]
Other assets [Abstract]
Derivatives assets at fair value	0	0
Other liabilities [Abstract]
Derivative liabilities at fair value	0	0
Recurring Fair Value Measurements [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Mortgage commitment derivatives
Other assets [Abstract]
Derivatives assets at fair value	0	0
Other liabilities [Abstract]
Derivative liabilities at fair value	0	0
Recurring Fair Value Measurements [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Other [Member]
Other assets [Abstract]
Derivatives assets at fair value	0	0
Other liabilities [Abstract]
Derivative liabilities at fair value	0	0
Recurring Fair Value Measurements [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	0	0
Recurring Fair Value Measurements [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Fannie Mae [Member] \| Senior floating [Member]
Liabilities [Abstract]
Long-term debt, fair value	0	0
Recurring Fair Value Measurements [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	0	0
Recurring Fair Value Measurements [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Fannie Mae [Member]
Assets [Abstract]
Trading securities	0	0
Available-for-sale securities	0	0
Recurring Fair Value Measurements [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Other agency [Member]
Assets [Abstract]
Trading securities	0	0
Available-for-sale securities	0	0
Recurring Fair Value Measurements [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Alt-A and subprime private-label securities [Member]
Assets [Abstract]
Trading securities	0	0
Available-for-sale securities	0	0
Recurring Fair Value Measurements [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Mortgage revenue bonds [Member]
Assets [Abstract]
Available-for-sale securities	0	0
Recurring Fair Value Measurements [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Other [Member]
Assets [Abstract]
Available-for-sale securities	0	0
Recurring Fair Value Measurements [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| U.S. Treasury securities [Member]
Assets [Abstract]
Trading securities	35,020	35,502
Recurring Fair Value Measurements [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Other securities [Member]
Assets [Abstract]
Trading securities	0	0
Recurring Fair Value Measurements [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Assets [Abstract]
Cash equivalents		0
Trading securities	5,812	6,332
Available-for-sale securities	2,230	2,477
Mortgage loans held for investment, at fair value	7,818	7,985
Other assets [Abstract]
Derivatives assets at fair value	2,129	2,515
Total assets at fair value	17,989	19,309
Liabilities [Abstract]
Long-term debt, fair value	29,132	30,027
Other liabilities [Abstract]
Derivative liabilities at fair value	2,886	3,077
Total liabilities at fair value	32,018	33,104
Recurring Fair Value Measurements [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Swaps [Member]
Other assets [Abstract]
Derivatives assets at fair value	1,633	1,962
Other liabilities [Abstract]
Derivative liabilities at fair value	1,891	2,089
Recurring Fair Value Measurements [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Swaptions [Member]
Other assets [Abstract]
Derivatives assets at fair value	97	211
Other liabilities [Abstract]
Derivative liabilities at fair value	332	342
Recurring Fair Value Measurements [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Mortgage commitment derivatives
Other assets [Abstract]
Derivatives assets at fair value	399	342
Other liabilities [Abstract]
Derivative liabilities at fair value	663	646
Recurring Fair Value Measurements [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Other [Member]
Other assets [Abstract]
Derivatives assets at fair value	0	0
Other liabilities [Abstract]
Derivative liabilities at fair value	0	0
Recurring Fair Value Measurements [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	6,306	6,475
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	6,306	6,475
Recurring Fair Value Measurements [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	22,826	23,552
Recurring Fair Value Measurements [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Fannie Mae [Member]
Assets [Abstract]
Trading securities	1,516	1,435
Available-for-sale securities	1,553	1,645
Recurring Fair Value Measurements [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Other agency [Member]
Assets [Abstract]
Trading securities	3,158	3,503
Available-for-sale securities	242	256
Recurring Fair Value Measurements [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Alt-A and subprime private-label securities [Member]
Assets [Abstract]
Trading securities	1,054	1,305
Available-for-sale securities	429	568
Recurring Fair Value Measurements [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Mortgage revenue bonds [Member]
Assets [Abstract]
Available-for-sale securities	0	0
Recurring Fair Value Measurements [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Other [Member]
Assets [Abstract]
Available-for-sale securities	6	8
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 Other Observable Inputs (Level 2) [Member] \| Other securities [Member]
Assets [Abstract]
Trading securities	84	89
Recurring Fair Value Measurements [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Assets [Abstract]
Cash equivalents		0
Trading securities	67	33
Available-for-sale securities	984	952
Mortgage loans held for investment, at fair value	934	937
Other assets [Abstract]
Derivatives assets at fair value	236	209
Total assets at fair value	2,221	2,131
Liabilities [Abstract]
Long-term debt, fair value	600	552
Other liabilities [Abstract]
Derivative liabilities at fair value	33	15
Total liabilities at fair value	633	567
Recurring Fair Value Measurements [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Swaps [Member]
Other assets [Abstract]
Derivatives assets at fair value	134	115
Other liabilities [Abstract]
Derivative liabilities at fair value	1	2
Recurring Fair Value Measurements [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Swaptions [Member]
Other assets [Abstract]
Derivatives assets at fair value	0	0
Other liabilities [Abstract]
Derivative liabilities at fair value	0	0
Recurring Fair Value Measurements [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Mortgage commitment derivatives
Other assets [Abstract]
Derivatives assets at fair value	40	37
Other liabilities [Abstract]
Derivative liabilities at fair value	3	2
Recurring Fair Value Measurements [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Other [Member]
Other assets [Abstract]
Derivatives assets at fair value	62	57
Other liabilities [Abstract]
Derivative liabilities at fair value	29	11
Recurring Fair Value Measurements [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Fannie Mae [Member]
Liabilities [Abstract]
Long-term debt, fair value	376	351
Recurring Fair Value Measurements [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Fannie Mae [Member] \| Senior floating [Member]
Liabilities [Abstract]
Long-term debt, fair value	376	351
Recurring Fair Value Measurements [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Consolidated Trusts [Member]
Liabilities [Abstract]
Long-term debt, fair value	224	201
Recurring Fair Value Measurements [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Fannie Mae [Member]
Assets [Abstract]
Trading securities	67	32
Available-for-sale securities	199	152
Recurring Fair Value Measurements [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Other agency [Member]
Assets [Abstract]
Trading securities	0	0
Available-for-sale securities	0	0
Recurring Fair Value Measurements [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Alt-A and subprime private-label securities [Member]
Assets [Abstract]
Trading securities	0	1
Available-for-sale securities	23	24
Recurring Fair Value Measurements [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Mortgage revenue bonds [Member]
Assets [Abstract]
Available-for-sale securities	425	434
Recurring Fair Value Measurements [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Other [Member]
Assets [Abstract]
Available-for-sale securities	337	342
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] \| Significant Unobservable Inputs (Level 3) [Member] \| Other securities [Member]
Assets [Abstract]
Trading securities	$ 0	$ 0

Fair Value Level 3 Rollforward

Fair Value Level 3 Rollforward (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Trading securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	$ 2	$ 1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	33	1,201
Total gains (losses) (realized/unrealized) Included in Net Income	2	85
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	0
Purchases	0	1
Sales	0	(1,060)
Issues	0	0
Settlements	(1)	(6)
Transfers out of Level 3	0	(137)
Transfers into Level 3	33	0
Ending Balance	67	84
Trading securities [Member] \| Fannie Mae [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	2	1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	32	971
Total gains (losses) (realized/unrealized) Included in Net Income	2	171
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	0
Purchases	0	1
Sales	0	(1,060)
Issues	0	0
Settlements	0	0
Transfers out of Level 3	0	0
Transfers into Level 3	33	0
Ending Balance	67	83
Trading securities [Member] \| Other agency [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance		35
Total gains (losses) (realized/unrealized) Included in Net Income		(1)
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)		0
Purchases		0
Sales		0
Issues		0
Settlements		(1)
Transfers out of Level 3		(33)
Transfers into Level 3		0
Ending Balance		0
Trading securities [Member] \| Alt-A and subprime private-label securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1	195
Total gains (losses) (realized/unrealized) Included in Net Income	0	(85)
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	0
Purchases	0	0
Sales	0	0
Issues	0	0
Settlements	(1)	(5)
Transfers out of Level 3	0	(104)
Transfers into Level 3	0	0
Ending Balance	0	1
Available-for-sale securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	952	1,313
Total gains (losses) (realized/unrealized) Included in Net Income	7	18
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	(1)	(64)
Purchases	0	0
Sales	0	(11)
Issues	0	0
Settlements	(18)	(133)
Transfers out of Level 3	(41)	(4)
Transfers into Level 3	85	0
Ending Balance	984	1,119
Available-for-sale securities [Member] \| Fannie Mae [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	152	208
Total gains (losses) (realized/unrealized) Included in Net Income	0	0
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	4	(4)
Purchases	0	0
Sales	0	0
Issues	0	0
Settlements	0	(2)
Transfers out of Level 3	(41)	0
Transfers into Level 3	84	0
Ending Balance	199	202
Available-for-sale securities [Member] \| Alt-A and subprime private-label securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	24	77
Total gains (losses) (realized/unrealized) Included in Net Income	0	0
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	(45)
Purchases	0	0
Sales	0	0
Issues	0	0
Settlements	(1)	(1)
Transfers out of Level 3	0	(4)
Transfers into Level 3	0	0
Ending Balance	23	27
Available-for-sale securities [Member] \| Mortgage revenue bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	434	671
Total gains (losses) (realized/unrealized) Included in Net Income	0	11
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	(13)
Purchases	0	0
Sales	0	(11)
Issues	0	0
Settlements	(9)	(119)
Transfers out of Level 3	0	0
Transfers into Level 3	0	0
Ending Balance	425	539
Available-for-sale securities [Member] \| Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	342	357
Total gains (losses) (realized/unrealized) Included in Net Income	7	7
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	(5)	(2)
Purchases	0	0
Sales	0	0
Issues	0	0
Settlements	(8)	(11)
Transfers out of Level 3	0	0
Transfers into Level 3	1	0
Ending Balance	337	351
Mortgage loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	11	11
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	937	1,116
Total gains (losses) (realized/unrealized) Included in Net Income	14	17
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	0
Purchases	0	0
Sales	0	0
Issues	0	0
Settlements	(34)	(48)
Transfers out of Level 3	(28)	(36)
Transfers into Level 3	45	53
Ending Balance	934	1,102
Net derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	44	(22)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	194	134
Total gains (losses) (realized/unrealized) Included in Net Income	98	(58)
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	0
Purchases	0	0
Sales	0	0
Issues	0	0
Settlements	(89)	4
Transfers out of Level 3	0	53
Transfers into Level 3	0	0
Ending Balance	203	133
Long-term debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	(26)	20
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(552)	(958)
Total gains (losses) (realized/unrealized) Included in Net Income	28	22
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	0
Purchases	0	0
Sales	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Issuances	0	1
Settlements	5	10
Transfers out of Level 3	49	154
Transfers into Level 3	(74)	(48)
Ending Balance	(600)	(819)
Long-term debt [Member] \| Consolidated Trusts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	(1)	1
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(201)	(582)
Total gains (losses) (realized/unrealized) Included in Net Income	(3)	3
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	0
Purchases	0	0
Sales	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Issuances	0	1
Settlements	5	10
Transfers out of Level 3	49	154
Transfers into Level 3	(74)	(48)
Ending Balance	(224)	(462)
Long-term debt [Member] \| Senior floating [Member] \| Fannie Mae [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	(25)	19
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(351)	(376)
Total gains (losses) (realized/unrealized) Included in Net Income	(25)	(19)
Total gains (losses) (realized/unrealized) Included in Other Comprehensive Income (Loss)	0	0
Purchases	0	0
Sales	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Issuances	0	0
Settlements	0	0
Transfers out of Level 3	0	0
Transfers into Level 3	0	0
Ending Balance	(376)	(357)
Other Comprehensive Income (Loss) [Member] \| Trading securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0
Other Comprehensive Income (Loss) [Member] \| Trading securities [Member] \| Fannie Mae [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0
Other Comprehensive Income (Loss) [Member] \| Trading securities [Member] \| Other agency [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0
Other Comprehensive Income (Loss) [Member] \| Trading securities [Member] \| Alt-A and subprime private-label securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0
Other Comprehensive Income (Loss) [Member] \| Available-for-sale securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	(2)	(10)
Other Comprehensive Income (Loss) [Member] \| Available-for-sale securities [Member] \| Fannie Mae [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	2	(3)
Other Comprehensive Income (Loss) [Member] \| Available-for-sale securities [Member] \| Alt-A and subprime private-label securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	1
Other Comprehensive Income (Loss) [Member] \| Available-for-sale securities [Member] \| Mortgage revenue bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	(8)
Other Comprehensive Income (Loss) [Member] \| Available-for-sale securities [Member] \| Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	(4)	0
Other Comprehensive Income (Loss) [Member] \| Mortgage loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0
Other Comprehensive Income (Loss) [Member] \| Net derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0
Other Comprehensive Income (Loss) [Member] \| Long-term debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0
Other Comprehensive Income (Loss) [Member] \| Long-term debt [Member] \| Consolidated Trusts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0
Other Comprehensive Income (Loss) [Member] \| Long-term debt [Member] \| Senior floating [Member] \| Fannie Mae [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	$ 0	$ 0

Fair Value Level 3 Valuation In

Fair Value Level 3 Valuation Inputs (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Fair Value Inputs, Quantitative Information [Line Items]
Derivatives	$ 522	$ 401
Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	40,899	41,867
Available-for-sale securities	3,214	3,429
Assets, Fair Value Disclosure	53,449	55,424
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	35,020	35,502
Available-for-sale securities	0	0
Assets, Fair Value Disclosure	69,661	69,575
Mortgage loans held-for-sale, at lower of cost or fair value	0	0
Liabilities, Fair Value Disclosure		0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	35,020	35,502
Available-for-sale securities	0	0
Assets, Fair Value Disclosure	35,020	36,250
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Fair Value, Measurements, Nonrecurring [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	0	0
Significant Other Observable Inputs (Level 2) [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	5,812	6,332
Available-for-sale securities	2,230	2,477
Assets, Fair Value Disclosure	3,039,232	3,053,308
Mortgage loans held-for-sale, at lower of cost or fair value	2,729	238
Significant Other Observable Inputs (Level 2) [Member] \| Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	5,812	6,332
Available-for-sale securities	2,230	2,477
Assets, Fair Value Disclosure	17,989	19,309
Significant Other Observable Inputs (Level 2) [Member] \| Fair Value, Measurements, Nonrecurring [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	946	91
Liabilities, Fair Value Disclosure	0	0
Significant Unobservable Inputs (Level 3) [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	67	33
Available-for-sale securities	984	952
Assets, Fair Value Disclosure	284,797	225,812
Mortgage loans held-for-sale, at lower of cost or fair value	7,931	7,856
Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	67	33
Available-for-sale securities	984	952
Derivatives	203	194
Assets, Fair Value Disclosure	2,221	2,131
Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Derivatives	71	81
Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Dealer Mark [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Derivatives	132	113
Significant Unobservable Inputs (Level 3) [Member] \| Fair Value, Measurements, Nonrecurring [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	3,934	3,771
Mortgage loans held-for-sale, at lower of cost or fair value	2,316	1,750
Significant Unobservable Inputs (Level 3) [Member] \| Fair Value, Measurements, Nonrecurring [Member] \| Single Vendor Without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	828	1,119
Significant Unobservable Inputs (Level 3) [Member] \| Fair Value, Measurements, Nonrecurring [Member] \| Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	1	0
Significant Unobservable Inputs (Level 3) [Member] \| Fair Value, Measurements, Nonrecurring [Member] \| Consensus Without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	1,487	631
Agency \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	199
Agency \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	67	32
Available-for-sale securities	94	152
Agency \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Consensus Without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	105
Alt-A and subprime private-label securities [Member] \| Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	1,054	1,306
Available-for-sale securities	452	592
Alt-A and subprime private-label securities [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	0	0
Available-for-sale securities	0	0
Alt-A and subprime private-label securities [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	1,054	1,305
Available-for-sale securities	429	568
Alt-A and subprime private-label securities [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	0	1
Available-for-sale securities	23	24
Alt-A and subprime private-label securities [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	23	24
Mortgage revenue bonds [Member] \| Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	425	434
Mortgage revenue bonds [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	0	0
Mortgage revenue bonds [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	0	0
Mortgage revenue bonds [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	425	434
Mortgage revenue bonds [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Single Vendor With Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	$ 304	$ 349
Mortgage revenue bonds [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Single Vendor With Inputs [Member] \| Available-for-sale securities [Member] \| Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)	(16.00%)	0.50%
Mortgage revenue bonds [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Single Vendor With Inputs [Member] \| Available-for-sale securities [Member] \| Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)	(265.20%)	(333.28%)
Mortgage revenue bonds [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Single Vendor With Inputs [Member] \| Available-for-sale securities [Member] \| Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)	(71.20%)	(59.00%)
Mortgage revenue bonds [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities		$ 1
Available-for-sale securities	$ 121	85
Other [Member] \| Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	343	350
Other [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	0	0
Other [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	6	8
Other [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	337	342
Other [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	48	48
Other [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Discounted Cash Flow with Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities	$ 289	$ 294
Other [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Discounted Cash Flow with Inputs [Member] \| Available-for-sale securities [Member] \| Minimum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)	(68.20%)	(75.40%)
Other [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Discounted Cash Flow with Inputs [Member] \| Available-for-sale securities [Member] \| Minimum [Member] \| Measurement Input, Default Rate [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Debt Securities, Available-for-sale, Measurement Input (%)	4.1	4.7
Other [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Discounted Cash Flow with Inputs [Member] \| Available-for-sale securities [Member] \| Minimum [Member] \| Measurement Input, Constant Prepayment Rate [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Debt Securities, Available-for-sale, Measurement Input (%)	4.6	8.2
Other [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Discounted Cash Flow with Inputs [Member] \| Available-for-sale securities [Member] \| Minimum [Member] \| Measurement Input, Loss Severity [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Debt Securities, Available-for-sale, Measurement Input (%)	0.950	0.700
Other [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Discounted Cash Flow with Inputs [Member] \| Available-for-sale securities [Member] \| Maximum [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)	(290.00%)	(390.00%)
Other [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Discounted Cash Flow with Inputs [Member] \| Available-for-sale securities [Member] \| Weighted Average [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (%)	(289.40%)	(389.10%)
Other [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Discounted Cash Flow with Inputs [Member] \| Available-for-sale securities [Member] \| Weighted Average [Member] \| Measurement Input, Default Rate [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Debt Securities, Available-for-sale, Measurement Input (%)	4.1	4.7
Other [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Discounted Cash Flow with Inputs [Member] \| Available-for-sale securities [Member] \| Weighted Average [Member] \| Measurement Input, Constant Prepayment Rate [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Debt Securities, Available-for-sale, Measurement Input (%)	4.6	8.2
Other [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Recurring Fair Value Measurements [Member] \| Discounted Cash Flow with Inputs [Member] \| Available-for-sale securities [Member] \| Weighted Average [Member] \| Measurement Input, Loss Severity [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Debt Securities, Available-for-sale, Measurement Input (%)	0.950	0.700

Fair Value Level 3 Valuation -

Fair Value Level 3 Valuation - Nonrecurring (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	$ 8,752	$ 8,922
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	2,729	238
Mortgage loans held for investment, at fair value	2,982,238	2,990,104
Total assets at fair value	3,039,232	3,053,308
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	7,931	7,856
Mortgage loans held for investment, at fair value	275,207	216,404
Total assets at fair value	284,797	225,812
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	946	91
Fair Value, Measurements, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	2,316	1,750
Total assets at fair value	3,934	3,771
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	828	1,119
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	1,487	631
Fair Value, Measurements, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held-for-sale, at lower of cost or fair value	1	0
Other assets	$ 0	$ 0
Fair Value, Measurements, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Accepted Offers [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Number of Acquired Properties Valuated, Percentage	18.00%	15.00%
Fair Value, Measurements, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Proprietary Home Price Model and Appraisals [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Number of Acquired Properties Valuated, Percentage	78.00%	82.00%
Fair Value, Measurements, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Single-family [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Acquired property, net	$ 841	$ 1,011
Fair Value, Measurements, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Single-family [Member] \| Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Acquired property, net	37	41
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	609	818
Acquired property, net	147	219
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	153	151
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	346	419
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	158	181
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	163	142
Fair Value, Measurements, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Multifamily [Member] \| Various Valuation Technique without Inputs [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage loans held for investment, at fair value	10	40
Acquired property, net	5	50
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	$ 153	$ 102

Fair Value Fair Value of Financ

Fair Value Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Fair Value Measurement [Domain]
Financial assets [Abstract]
Derivative assets, gross amount offset	$ (1,781)	$ (2,266)
Financial liabilities [Abstract]
Derivative liabilities, gross amount offset	(2,126)	(2,315)
Mortgage loans held for investment, at fair value	8,752	8,922
Derivative assets, gross amount offset	(1,781)	(2,266)
Derivative liabilities, gross amount offset	(2,126)	(2,315)
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets [Abstract]
Cash and cash equivalents and restricted cash	34,641	34,073
Federal funds sold and securities purchased under agreements to resell or similar arrangements	0	0
Trading securities	35,020	35,502
Available-for-sale securities	0	0
Mortgage loans held for sale	0	0
Mortgage loans held for investment, at fair value	0	0
Advances to lenders	0	0
Derivatives assets at fair value	0	0
Guaranty assets and buy-ups	0	0
Total financial assets	69,661	69,575
Financial liabilities [Abstract]
Derivative liabilities at fair value	0	0
Guaranty obligations	0	0
Total financial liabilities	0	0
Significant Other Observable Inputs (Level 2) [Member]
Financial assets [Abstract]
Cash and cash equivalents and restricted cash	17,600	15,350
Federal funds sold and securities purchased under agreements to resell or similar arrangements	22,250	32,938
Trading securities	5,812	6,332
Available-for-sale securities	2,230	2,477
Mortgage loans held for sale	2,729	238
Mortgage loans held for investment, at fair value	2,982,238	2,990,104
Advances to lenders	4,244	3,354
Derivatives assets at fair value	2,129	2,515
Guaranty assets and buy-ups	0	0
Total financial assets	3,039,232	3,053,308
Financial liabilities [Abstract]
Derivative liabilities at fair value	2,886	3,077
Guaranty obligations	0	0
Total financial liabilities	3,348,843	3,303,620
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	67	33
Available-for-sale securities	984	952
Mortgage loans held for sale	7,931	7,856
Mortgage loans held for investment, at fair value	275,207	216,404
Advances to lenders	2	2
Derivatives assets at fair value	236	209
Guaranty assets and buy-ups	370	356
Total financial assets	284,797	225,812
Financial liabilities [Abstract]
Derivative liabilities at fair value	33	15
Guaranty obligations	107	121
Total financial liabilities	44,158	39,950
Fannie Mae [Member]
Financial liabilities [Abstract]
Long-term debt	6,682	6,826
Fannie Mae [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial liabilities [Abstract]
Short-term debt	0	0
Long-term debt	0	0
Fannie Mae [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Financial liabilities [Abstract]
Short-term debt	23,078	24,901
Long-term debt	204,060	211,403
Fannie Mae [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Financial liabilities [Abstract]
Short-term debt	0	0
Long-term debt	813	771
Consolidated Trusts [Member]
Financial liabilities [Abstract]
Long-term debt	23,050	23,753
Consolidated Trusts [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial liabilities [Abstract]
Long-term debt	0	0
Consolidated Trusts [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Financial liabilities [Abstract]
Long-term debt	3,118,819	3,064,239
Consolidated Trusts [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Financial liabilities [Abstract]
Long-term debt	43,205	39,043
Carrying Value [Member]
Financial assets [Abstract]
Cash and cash equivalents and restricted cash	52,241	49,423
Federal funds sold and securities purchased under agreements to resell or similar arrangements	22,250	32,938
Trading securities	40,899	41,867
Available-for-sale securities	3,214	3,429
Mortgage loans held for sale	10,066	7,701
Mortgage loans held for investment, at fair value	3,249,699	3,241,694
Advances to lenders	4,246	3,356
Derivatives assets at fair value	584	458
Guaranty assets and buy-ups	159	147
Total financial assets	3,383,358	3,381,013
Financial liabilities [Abstract]
Derivative liabilities at fair value	793	777
Guaranty obligations	170	160
Total financial liabilities	3,395,973	3,392,857
Carrying Value [Member] \| Fannie Mae [Member]
Financial liabilities [Abstract]
Short-term debt	23,071	24,896
Long-term debt	198,167	207,178
Carrying Value [Member] \| Consolidated Trusts [Member]
Financial liabilities [Abstract]
Long-term debt	3,173,772	3,159,846
Estimated of Fair Value [Member]
Financial assets [Abstract]
Cash and cash equivalents and restricted cash	52,241	49,423
Federal funds sold and securities purchased under agreements to resell or similar arrangements	22,250	32,938
Trading securities	40,899	41,867
Available-for-sale securities	3,214	3,429
Mortgage loans held for sale	10,660	8,094
Mortgage loans held for investment, at fair value	3,257,445	3,206,508
Advances to lenders	4,246	3,356
Derivatives assets at fair value	584	458
Guaranty assets and buy-ups	370	356
Total financial assets	3,391,909	3,346,429
Financial liabilities [Abstract]
Derivative liabilities at fair value	793	777
Guaranty obligations	107	121
Total financial liabilities	3,390,875	3,341,255
Estimated of Fair Value [Member] \| Fannie Mae [Member]
Financial liabilities [Abstract]
Short-term debt	23,078	24,901
Long-term debt	204,873	212,174
Estimated of Fair Value [Member] \| Consolidated Trusts [Member]
Financial liabilities [Abstract]
Long-term debt	$ 3,162,024	$ 3,103,282

Fair Value Fair Value Option (D

Fair Value Fair Value Option (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Option, Quantitative Disclosures [Line Items]
Mortgage loans held for investment, at fair value	$ 8,752	$ 8,922
Fair value of nonaccrual loans	145	161
Difference between unpaid principal balance and the fair value of nonaccrual loans	16	19
Fair value of loans that are 90 days or more past due	95	102
Difference between unpaid principal balance and the fair value of these 90 days or more past due loans	$ 12	$ 14
Single-family [Member] \| Minimum [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Serious delinquency, days past due	90 days	90 days
Fannie Mae [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Long-term debt, fair value	$ 6,682	$ 6,826
Consolidated Trusts [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Long-term debt, fair value	23,050	23,753
Loans [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Mortgage loans held for investment, at fair value	8,752	8,922
Loans, unpaid principal balance	8,578	8,832
Long-term debt [Member] \| Fannie Mae [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Long-term debt, fair value	6,682	6,826
Long-term debt, unpaid principal balance	6,050	6,241
Long-term debt [Member] \| Consolidated Trusts [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Long-term debt, fair value	23,050	23,753
Long-term debt, unpaid principal balance	$ 21,216	$ 22,080

Fair Value Changes in FV under

Fair Value Changes in FV under the FV Option (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Loans [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value (gains) losses, net	$ (113)	$ 149
Long-term debt [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value (gains) losses, net	$ 330	$ (254)