Summary of Significant Accounting Policies	6 Months Ended
Jun. 30, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Organization We are a stockholder-owned corporation organized and existing under the Federal National Mortgage Association Charter Act (the “Charter Act” or our “charter”). We are a government-sponsored enterprise (“GSE”) and we are subject to government oversight and regulation. Our regulators include the Federal Housing Finance Agency (“FHFA”), the U.S. Department of Housing and Urban Development (“HUD”), the U.S. Securities and Exchange Commission (“SEC”), and the U.S. Department of the Treasury (“Treasury”). The U.S. government does not guarantee our securities or other obligations. Conservatorship On September 7, 2008, the Secretary of the Treasury and the Director of FHFA announced several actions taken by Treasury and FHFA regarding Fannie Mae, which included: (1) placing us in conservatorship, and (2) the execution of a senior preferred stock purchase agreement by our conservator, on our behalf, and Treasury, pursuant to which we issued to Treasury both senior preferred stock and a warrant to purchase common stock. Under the Federal Housing Enterprises Financial Safety and Soundness Act of 1992, as amended by the Federal Housing Finance Regulatory Reform Act of 2008 (together, the “GSE Act”), the conservator immediately succeeded to (1) all rights, titles, powers and privileges of Fannie Mae, and of any stockholder, officer or director of Fannie Mae with respect to Fannie Mae and its assets, and (2) title to the books, records and assets of any other legal custodian of Fannie Mae. The conservator has since delegated specified authorities to our Board of Directors and has delegated to management the authority to conduct our day-to-day operations. The conservator retains the authority to withdraw its delegations at any time. The conservatorship has no specified termination date and there continues to be significant uncertainty regarding our future, including how long we will continue to exist in our current form, the extent of our role in the market, how long we will be in conservatorship, what form we will have and what ownership interest, if any, our current common and preferred stockholders will hold in us after the conservatorship is terminated and whether we will continue to exist following conservatorship. Under the GSE Act, FHFA must place us into receivership if the Director of FHFA makes a written determination that our assets are less than our obligations or if we have not been paying our debts, in either case, for a period of 60 days. In addition, the Director of FHFA may place us into receivership at his discretion at any time for other reasons set forth in the GSE Act, including if we are critically undercapitalized or if we are undercapitalized and have no reasonable prospect of becoming adequately capitalized. Should we be placed into receivership, different assumptions would be required to determine the carrying value of our assets, which could lead to substantially different financial results. We are not aware of any plans of FHFA to fundamentally change our business model or capital structure in the near term. Impact of U.S. Government Support We continue to rely on support from Treasury to eliminate any net worth deficits we may experience in the future, which would otherwise trigger our being placed into receivership. Based on consideration of all the relevant conditions and events affecting our operations, including our reliance on the U.S. government, we continue to operate as a going concern and in accordance with our delegation of authority from FHFA. We believe that continued federal government support of our business, as well as our status as a GSE, are essential to maintaining our access to debt funding. Changes or perceived changes in federal government support of our business or our status as a GSE could materially and adversely affect our liquidity, financial condition and results of operations. Pursuant to the senior preferred stock purchase agreement, Treasury has committed to provide us with funding to help us maintain a positive net worth thereby avoiding the mandatory receivership trigger described above. We have received a total of $116.1 billion from Treasury pursuant to the senior preferred stock purchase agreement as of June 30, 2016. The aggregate liquidation preference of the senior preferred stock, including the initial aggregate liquidation preference of $1.0 billion, was $117.1 billion as of June 30, 2016. As of June 30, 2016, the amount of remaining funding available to us under the senior preferred stock purchase agreement was $117.6 billion. Based on the terms of the senior preferred stock, we paid Treasury a dividend of $919 million on June 30, 2016 based on our net worth of $2.1 billion as of March 31, 2016 less the applicable capital reserve amount of $1.2 billion. We expect to pay Treasury an additional dividend of $2.9 billion by September 30, 2016 based on our net worth of $4.1 billion as of June 30, 2016 less the applicable capital reserve amount of $1.2 billion. The capital reserve amount was $1.8 billion for dividend periods in 2015. The capital reserve amount will continue to be reduced by $600 million each year until it reaches zero on January 1, 2018. Basis of Presentation The accompanying unaudited interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and with the SEC’s instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and note disclosures required by GAAP for complete consolidated financial statements. In the opinion of management, all adjustments of a normal recurring nature considered necessary for a fair presentation have been included. The accompanying condensed consolidated financial statements include our accounts as well as the accounts of other entities in which we have a controlling financial interest. All intercompany accounts and transactions have been eliminated. To conform to our current period presentation, we have reclassified certain amounts reported in our prior periods’ condensed consolidated financial statements. Results for the six months ended June 30, 2016 may not necessarily be indicative of the results for the year ending December 31, 2016. The unaudited interim condensed consolidated financial statements as of and for the six months ended June 30, 2016 should be read in conjunction with our audited consolidated financial statements and related notes included in our Annual Report on Form 10-K for the year ended December 31, 2015 (“2015 Form 10-K”), filed with the SEC on February 19, 2016. Regulatory Capital FHFA stated that, during conservatorship, our existing statutory and FHFA-directed regulatory capital requirements will not be binding and FHFA will not issue quarterly capital classifications. We submit capital reports to FHFA and FHFA monitors our capital levels. The deficit of core capital over statutory minimum capital was $139.1 billion as of June 30, 2016 and $139.7 billion as of December 31, 2015. Under the terms of the senior preferred stock, we are required to pay Treasury a dividend each quarter, when, as and if declared, equal to the excess of our net worth as of the end of the preceding quarter over an applicable capital reserve amount. The Director of FHFA has directed us to make dividend payments on the senior preferred stock on a quarterly basis. Therefore, we do not expect to eliminate our deficit of core capital over statutory minimum capital. Related Parties As a result of our issuance to Treasury of the warrant to purchase shares of Fannie Mae common stock equal to 79.9% of the total number of shares of Fannie Mae common stock, we and Treasury are deemed related parties. As of June 30, 2016, Treasury held an investment in our senior preferred stock with an aggregate liquidation preference of $117.1 billion. FHFA’s control of both us and Freddie Mac has caused us, FHFA and Freddie Mac to be deemed related parties. In 2013, Fannie Mae and Freddie Mac established Common Securitization Solutions, LLC (“CSS”), a jointly owned limited liability company to operate a common securitization platform; therefore, CSS is deemed a related party. Transactions with Treasury Our administrative expenses were reduced by $15 million and $16 million for the three months ended June 30, 2016 and 2015, respectively, and $31 million and $32 million for the six months ended June 30, 2016 and 2015, respectively, due to reimbursements from Treasury and Freddie Mac for expenses incurred as program administrator for Treasury’s Home Affordable Modification Program (“HAMP”) and other initiatives under Treasury’s Making Home Affordable Program. During the three and six months ended June 30, 2016, we made tax payments of $250 million and $610 million, respectively, to the Internal Revenue Service (“IRS”), a bureau of Treasury. We made tax payments of $370 million during the three and six months ended June 30, 2015. We received no refund from the IRS during the six months ended June 30, 2016. We received a refund of $135 million from the IRS during the six months ended June 30, 2015 for income tax adjustments related to tax years 2004 through 2006. In 2009, we entered into a memorandum of understanding with Treasury, FHFA and Freddie Mac pursuant to which we agreed to provide assistance to state and local housing finance agencies (“HFAs”) through different programs, including a new issue bond (“NIB”) program. As of June 30, 2016, under the NIB program, Fannie Mae and Freddie Mac had $7.1 billion outstanding of pass-through securities backed by single-family and multifamily housing bonds issued by HFAs, which is less than 35% of the total original principal under the program, the amount of losses that Treasury would bear. Accordingly, we do not have a potential risk of loss under the NIB program. The fee revenue and expense related to the Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) are recorded in “Mortgage loans interest income” and “TCCA fees,” respectively, in our condensed consolidated statements of operations and comprehensive income. We recognized $453 million and $397 million in TCCA fees during the three months ended June 30, 2016 and 2015, respectively, and $893 million and $779 million for the six months ended June 30, 2016 and 2015, respectively, of which $453 million had not been remitted to Treasury as of June 30, 2016. We incurred expenses in connection with certain funding obligations under the GSE Act, a portion of which is attributable to Treasury’s Capital Magnet and HOPE Funds. These expenses, recognized in “Other expenses, net” in our 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 $31 million and $60 million in other expenses in connection with Treasury’s Capital Magnet and HOPE Funds for the three months ended June 30, 2016 and 2015, respectively, and $56 million and $112 million for the six months ended June 30, 2016 and 2015, respectively, of which $56 million resulting from 2016 purchases had not been remitted as of June 30, 2016. In addition to the transactions with Treasury mentioned above, we also purchase and sell Treasury securities in the normal course of business. As of June 30, 2016 and December 31, 2015, we held Treasury securities with a fair value of $29.7 billion and $29.5 billion, respectively, and accrued interest receivable of $24 million and $15 million, respectively. We recognized interest income on these securities held by us of $33 million and $5 million for the three months ended June 30, 2016 and 2015, respectively, and $65 million and $9 million for the six months ended June 30, 2016 and 2015, respectively. Transactions with Freddie Mac As of June 30, 2016 and December 31, 2015, we held Freddie Mac mortgage-related securities with a fair value of $3.4 billion and $5.6 billion, respectively, and accrued interest receivable of $14 million and $22 million, respectively. We recognized interest income on these securities held by us of $36 million and $58 million for the three months ended June 30, 2016 and 2015, respectively, and $81 million and $119 million for the six months ended June 30, 2016 and 2015, respectively. In addition, Freddie Mac may be an investor in variable interest entities (“VIEs”) that we have consolidated, and we may be an investor in VIEs that Freddie Mac has consolidated. Transactions with FHFA The GSE Act authorizes FHFA to establish an annual assessment for regulated entities, including Fannie Mae, which is payable on a semi-annual basis (April and October), for FHFA’s costs and expenses, as well as to maintain FHFA’s working capital. We recognized FHFA assessment fees, which are recorded in “Administrative expenses” in our condensed consolidated statements of operations and comprehensive income, of $28 million for the three months ended June 30, 2016 and 2015, and $56 million for the six months ended June 30, 2016 and 2015. Transactions with CSS In connection with our jointly owned company with Freddie Mac, we contributed $35 million and $17 million for the three months ended June 30, 2016 and 2015, respectively, and $65 million and $30 million for the six months ended June 30, 2016 and 2015, respectively, of capital into CSS. No other transactions outside of normal business activities have occurred between us and Freddie Mac during the six months ended June 30, 2016 and 2015. Use of Estimates Preparing condensed consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that affect our reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities as of the dates of our condensed consolidated financial statements, as well as our reported amounts of revenues and expenses during the reporting periods. Management has made significant estimates in a variety of areas including, but not limited to, valuation of certain financial instruments and other assets and liabilities and allowance for loan losses. Actual results could be different from these estimates. On January 1, 2015, we adopted regulatory guidance issued by FHFA which prescribes, among other things, guidance on when a loan should be charged off. This change in estimate resulted in the recognition on January 1, 2015 of (1) $1.8 billion in charge-offs of held for investment loans, (2) $724 million in charge-offs of preforeclosure property taxes and insurance receivable and (3) a reduction to our allowance for loan losses and our allowance for preforeclosure property taxes and insurance receivable in amounts equal to charge-offs recognized in connection with held for investment loans and preforeclosure property taxes and insurance receivable. For the majority of our delinquent single-family loans, we charge off the loan at the date of foreclosure or other liquidation event (such as a deed-in-lieu of foreclosure or a short sale). For a subset of delinquent single-family loans, we charge off the portion of the loans that is deemed uncollectible prior to foreclosure when the loans have been delinquent for a specified length of time and meet specified mark-to-market loan-to-value (“LTV”) ratios. We continue to enhance our data collection and analysis efforts to further refine our loss estimates as we obtain incremental information on the performance of our loans. Debt We issue debt in the form of credit risk transfer notes under the Connecticut Avenue Securities (“CAS”) program where repayment of the debt is linked to a reference portfolio of mortgage loans. We account for CAS notes issued in 2016 at amortized cost. As credit events occur and the principal balance of these CAS notes is legally reduced, we recognize an extinguishment gain. We elected the fair value option on CAS notes that were issued prior to 2016. New Accounting Guidance Effective January 1, 2016, we adopted guidance regarding consolidation of legal entities such as limited partnerships, limited liability corporations and securitization structures. The impact of the adoption was not material to our condensed consolidated financial statements. In February 2016, the Financial Accounting Standards Board (“FASB”) issued guidance on leases. The guidance clarified the definition of a lease and requires lessees to recognize on the balance sheet a right-of-use asset, representing its right to use the underlying asset for the lease term, and a corresponding lease liability for all leases with terms greater than 12 months. This guidance supersedes the existing lease guidance; however, we must continue to classify leases to determine how to recognize lease-related expense in our condensed consolidated statements of operations and comprehensive income. The new guidance is effective for us on January 1, 2019. We have evaluated this guidance and determined it will not have a material impact on our condensed consolidated financial statements. In June 2016, FASB issued guidance that changes the impairment model for most financial assets and certain other instruments. For loans, held-to-maturity debt securities and other financial assets recorded at amortized cost, entities will be required to use a new forward-looking “expected loss” model that will replace today’s “incurred loss” model and generally will result in the earlier recognition of allowances for losses. The guidance is effective on January 1, 2020 with early adoption permitted on January 1, 2019. We will recognize the impact of the new guidance through a cumulative-effect adjustment to retained earnings as of the beginning of the year of adoption. We are currently evaluating the impact of this guidance on our financial statements and the timing of our adoption.

Summary of Significant Accounting Policies

Organization

We are a stockholder-owned corporation organized and existing under the Federal National Mortgage Association Charter Act (the “Charter Act” or our “charter”). We are a government-sponsored enterprise (“GSE”) and we are subject to government oversight and regulation. Our regulators include the Federal Housing Finance Agency (“FHFA”), the U.S. Department of Housing and Urban Development (“HUD”), the U.S. Securities and Exchange Commission (“SEC”), and the U.S. Department of the Treasury (“Treasury”). The U.S. government does not guarantee our securities or other obligations.

Conservatorship

On September 7, 2008, the Secretary of the Treasury and the Director of FHFA announced several actions taken by Treasury and FHFA regarding Fannie Mae, which included: (1) placing us in conservatorship, and (2) the execution of a senior preferred stock purchase agreement by our conservator, on our behalf, and Treasury, pursuant to which we issued to Treasury both senior preferred stock and a warrant to purchase common stock.

Under the Federal Housing Enterprises Financial Safety and Soundness Act of 1992, as amended by the Federal Housing Finance Regulatory Reform Act of 2008 (together, the “GSE Act”), the conservator immediately succeeded to (1) all rights, titles, powers and privileges of Fannie Mae, and of any stockholder, officer or director of Fannie Mae with respect to Fannie Mae and its assets, and (2) title to the books, records and assets of any other legal custodian of Fannie Mae. The conservator has since delegated specified authorities to our Board of Directors and has delegated to management the authority to conduct our day-to-day operations. The conservator retains the authority to withdraw its delegations at any time.

The conservatorship has no specified termination date and there continues to be significant uncertainty regarding our future, including how long we will continue to exist in our current form, the extent of our role in the market, how long we will be in conservatorship, what form we will have and what ownership interest, if any, our current common and preferred stockholders will hold in us after the conservatorship is terminated and whether we will continue to exist following conservatorship. Under the GSE Act, FHFA must place us into receivership if the Director of FHFA makes a written determination that our assets are less than our obligations or if we have not been paying our debts, in either case, for a period of 60 days. In addition, the Director of FHFA may place us into receivership at his discretion at any time for other reasons set forth in the GSE Act, including if we are critically undercapitalized or if we are undercapitalized and have no reasonable prospect of becoming adequately capitalized. Should we be placed into receivership, different assumptions would be required to determine the carrying value of our assets, which could lead to substantially different financial results. We are not aware of any plans of FHFA to fundamentally change our business model or capital structure in the near term.

Impact of U.S. Government Support

We continue to rely on support from Treasury to eliminate any net worth deficits we may experience in the future, which would otherwise trigger our being placed into receivership. Based on consideration of all the relevant conditions and events affecting our operations, including our reliance on the U.S. government, we continue to operate as a going concern and in accordance with our delegation of authority from FHFA.

We believe that continued federal government support of our business, as well as our status as a GSE, are essential to maintaining our access to debt funding. Changes or perceived changes in federal government support of our business or our status as a GSE could materially and adversely affect our liquidity, financial condition and results of operations.

Pursuant to the senior preferred stock purchase agreement, Treasury has committed to provide us with funding to help us maintain a positive net worth thereby avoiding the mandatory receivership trigger described above. We have received a total of $116.1 billion from Treasury pursuant to the senior preferred stock purchase agreement as of June 30, 2016. The aggregate liquidation preference of the senior preferred stock, including the initial aggregate liquidation preference of $1.0 billion, was $117.1 billion as of June 30, 2016. As of June 30, 2016, the amount of remaining funding available to us under the senior preferred stock purchase agreement was $117.6 billion.

Based on the terms of the senior preferred stock, we paid Treasury a dividend of $919 million on June 30, 2016 based on our net worth of $2.1 billion as of March 31, 2016 less the applicable capital reserve amount of $1.2 billion. We expect to pay Treasury an additional dividend of $2.9 billion by September 30, 2016 based on our net worth of $4.1 billion as of June 30, 2016 less the applicable capital reserve amount of $1.2 billion. The capital reserve amount was $1.8 billion for dividend periods in 2015. The capital reserve amount will continue to be reduced by $600 million each year until it reaches zero on January 1, 2018.

Basis of Presentation

The accompanying unaudited interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and with the SEC’s instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and note disclosures required by GAAP for complete consolidated financial statements. In the opinion of management, all adjustments of a normal recurring nature considered necessary for a fair presentation have been included. The accompanying condensed consolidated financial statements include our accounts as well as the accounts of other entities in which we have a controlling financial interest. All intercompany accounts and transactions have been eliminated. To conform to our current period presentation, we have reclassified certain amounts reported in our prior periods’ condensed consolidated financial statements. Results for the six months ended June 30, 2016 may not necessarily be indicative of the results for the year ending December 31, 2016. The unaudited interim condensed consolidated financial statements as of and for the six months ended June 30, 2016 should be read in conjunction with our audited consolidated financial statements and related notes included in our Annual Report on Form 10-K for the year ended December 31, 2015 (“2015 Form 10-K”), filed with the SEC on February 19, 2016.

Regulatory Capital

FHFA stated that, during conservatorship, our existing statutory and FHFA-directed regulatory capital requirements will not be binding and FHFA will not issue quarterly capital classifications. We submit capital reports to FHFA and FHFA monitors our capital levels. The deficit of core capital over statutory minimum capital was $139.1 billion as of June 30, 2016 and $139.7 billion as of December 31, 2015.

Under the terms of the senior preferred stock, we are required to pay Treasury a dividend each quarter, when, as and if declared, equal to the excess of our net worth as of the end of the preceding quarter over an applicable capital reserve amount. The Director of FHFA has directed us to make dividend payments on the senior preferred stock on a quarterly basis. Therefore, we do not expect to eliminate our deficit of core capital over statutory minimum capital.

Related Parties

As a result of our issuance to Treasury of the warrant to purchase shares of Fannie Mae common stock equal to 79.9% of the total number of shares of Fannie Mae common stock, we and Treasury are deemed related parties. As of June 30, 2016, Treasury held an investment in our senior preferred stock with an aggregate liquidation preference of $117.1 billion. FHFA’s control of both us and Freddie Mac has caused us, FHFA and Freddie Mac to be deemed related parties. In 2013, Fannie Mae and Freddie Mac established Common Securitization Solutions, LLC (“CSS”), a jointly owned limited liability company to operate a common securitization platform; therefore, CSS is deemed a related party.

Transactions with Treasury

Our administrative expenses were reduced by $15 million and $16 million for the three months ended June 30, 2016 and 2015, respectively, and $31 million and $32 million for the six months ended June 30, 2016 and 2015, respectively, due to reimbursements from Treasury and Freddie Mac for expenses incurred as program administrator for Treasury’s Home Affordable Modification Program (“HAMP”) and other initiatives under Treasury’s Making Home Affordable Program.

During the three and six months ended June 30, 2016, we made tax payments of $250 million and $610 million, respectively, to the Internal Revenue Service (“IRS”), a bureau of Treasury. We made tax payments of $370 million during the three and six months ended June 30, 2015. We received no refund from the IRS during the six months ended June 30, 2016. We received a refund of $135 million from the IRS during the six months ended June 30, 2015 for income tax adjustments related to tax years 2004 through 2006.

In 2009, we entered into a memorandum of understanding with Treasury, FHFA and Freddie Mac pursuant to which we agreed to provide assistance to state and local housing finance agencies (“HFAs”) through different programs, including a new issue bond (“NIB”) program. As of June 30, 2016, under the NIB program, Fannie Mae and Freddie Mac had $7.1 billion outstanding of pass-through securities backed by single-family and multifamily housing bonds issued by HFAs, which is less than 35% of the total original principal under the program, the amount of losses that Treasury would bear. Accordingly, we do not have a potential risk of loss under the NIB program.

The fee revenue and expense related to the Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) are recorded in “Mortgage loans interest income” and “TCCA fees,” respectively, in our condensed consolidated statements of operations and comprehensive income. We recognized $453 million and $397 million in TCCA fees during the three months ended June 30, 2016 and 2015, respectively, and $893 million and $779 million for the six months ended June 30, 2016 and 2015, respectively, of which $453 million had not been remitted to Treasury as of June 30, 2016.

We incurred expenses in connection with certain funding obligations under the GSE Act, a portion of which is attributable to Treasury’s Capital Magnet and HOPE Funds. These expenses, recognized in “Other expenses, net” in our 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 $31 million and $60 million in other expenses in connection with Treasury’s Capital Magnet and HOPE Funds for the three months ended June 30, 2016 and 2015, respectively, and $56 million and $112 million for the six months ended June 30, 2016 and 2015, respectively, of which $56 million resulting from 2016 purchases had not been remitted as of June 30, 2016.

In addition to the transactions with Treasury mentioned above, we also purchase and sell Treasury securities in the normal course of business. As of June 30, 2016 and December 31, 2015, we held Treasury securities with a fair value of $29.7 billion and $29.5 billion, respectively, and accrued interest receivable of $24 million and $15 million, respectively. We recognized interest income on these securities held by us of $33 million and $5 million for the three months ended June 30, 2016 and 2015, respectively, and $65 million and $9 million for the six months ended June 30, 2016 and 2015, respectively.

Transactions with Freddie Mac

As of June 30, 2016 and December 31, 2015, we held Freddie Mac mortgage-related securities with a fair value of $3.4 billion and $5.6 billion, respectively, and accrued interest receivable of $14 million and $22 million, respectively. We recognized interest income on these securities held by us of $36 million and $58 million for the three months ended June 30, 2016 and 2015, respectively, and $81 million and $119 million for the six months ended June 30, 2016 and 2015, respectively. In addition, Freddie Mac may be an investor in variable interest entities (“VIEs”) that we have consolidated, and we may be an investor in VIEs that Freddie Mac has consolidated.

Transactions with FHFA

The GSE Act authorizes FHFA to establish an annual assessment for regulated entities, including Fannie Mae, which is payable on a semi-annual basis (April and October), for FHFA’s costs and expenses, as well as to maintain FHFA’s working capital. We recognized FHFA assessment fees, which are recorded in “Administrative expenses” in our condensed consolidated statements of operations and comprehensive income, of $28 million for the three months ended June 30, 2016 and 2015, and $56 million for the six months ended June 30, 2016 and 2015.

Transactions with CSS

In connection with our jointly owned company with Freddie Mac, we contributed $35 million and $17 million for the three months ended June 30, 2016 and 2015, respectively, and $65 million and $30 million for the six months ended June 30, 2016 and 2015, respectively, of capital into CSS. No other transactions outside of normal business activities have occurred between us and Freddie Mac during the six months ended June 30, 2016 and 2015.

Use of Estimates

Preparing condensed consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that affect our reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities as of the dates of our condensed consolidated financial statements, as well as our reported amounts of revenues and expenses during the reporting periods. Management has made significant estimates in a variety of areas including, but not limited to, valuation of certain financial instruments and other assets and liabilities and allowance for loan losses. Actual results could be different from these estimates.

On January 1, 2015, we adopted regulatory guidance issued by FHFA which prescribes, among other things, guidance on when a loan should be charged off. This change in estimate resulted in the recognition on January 1, 2015 of (1) $1.8 billion in charge-offs of held for investment loans, (2) $724 million in charge-offs of preforeclosure property taxes and insurance receivable and (3) a reduction to our allowance for loan losses and our allowance for preforeclosure property taxes and insurance receivable in amounts equal to charge-offs recognized in connection with held for investment loans and preforeclosure property taxes and insurance receivable.

For the majority of our delinquent single-family loans, we charge off the loan at the date of foreclosure or other liquidation event (such as a deed-in-lieu of foreclosure or a short sale). For a subset of delinquent single-family loans, we charge off the portion of the loans that is deemed uncollectible prior to foreclosure when the loans have been delinquent for a specified length of time and meet specified mark-to-market loan-to-value (“LTV”) ratios. We continue to enhance our data collection and analysis efforts to further refine our loss estimates as we obtain incremental information on the performance of our loans.

Debt

We issue debt in the form of credit risk transfer notes under the Connecticut Avenue Securities (“CAS”) program where repayment of the debt is linked to a reference portfolio of mortgage loans. We account for CAS notes issued in 2016 at amortized cost. As credit events occur and the principal balance of these CAS notes is legally reduced, we recognize an extinguishment gain. We elected the fair value option on CAS notes that were issued prior to 2016.

New Accounting Guidance

Effective January 1, 2016, we adopted guidance regarding consolidation of legal entities such as limited partnerships, limited liability corporations and securitization structures. The impact of the adoption was not material to our condensed consolidated financial statements.

In February 2016, the Financial Accounting Standards Board (“FASB”) issued guidance on leases. The guidance clarified the definition of a lease and requires lessees to recognize on the balance sheet a right-of-use asset, representing its right to use the underlying asset for the lease term, and a corresponding lease liability for all leases with terms greater than 12 months. This guidance supersedes the existing lease guidance; however, we must continue to classify leases to determine how to recognize lease-related expense in our condensed consolidated statements of operations and comprehensive income. The new guidance is effective for us on January 1, 2019. We have evaluated this guidance and determined it will not have a material impact on our condensed consolidated financial statements.

In June 2016, FASB issued guidance that changes the impairment model for most financial assets and certain other instruments. For loans, held-to-maturity debt securities and other financial assets recorded at amortized cost, entities will be required to use a new forward-looking “expected loss” model that will replace today’s “incurred loss” model and generally will result in the earlier recognition of allowances for losses. The guidance is effective on January 1, 2020 with early adoption permitted on January 1, 2019. We will recognize the impact of the new guidance through a cumulative-effect adjustment to retained earnings as of the beginning of the year of adoption. We are currently evaluating the impact of this guidance on our financial statements and the timing of our adoption.