In April 2012, FHFA issued Advisory Bulletin AB 2012-02, “Framework for Adversely Classifying Loans, Other Real Estate Owned, and Other Assets and Listing Assets for Special Mention” (the “Advisory Bulletin”), which prescribes, among other things, classification of loans by risk category and provides guidance on when a loan should be charged off. The provisions of the Advisory Bulletin led us to re-evaluate our estimate of when a loan is deemed uncollectible. For the vast majority of our delinquent single-family loans, we will continue to charge-off the loan at the date of foreclosure or other liquidation event (such as a deed-in-lieu of foreclosure or a short sale). For a relatively small subset of delinquent loans deemed to be uncollectible prior to foreclosure based upon our historical data, we charge off the portion of the loan (including preforeclosure taxes and insurance receivables that pertain to such loans) deemed to be uncollectible prior to the date of foreclosure or other liquidation event, which given our current credit analytics and historical data, is when the loans are excessively delinquent and the outstanding loan balance exceeds the fair value of the underlying property. This change in estimate resulted in the charge-offs of loans HFI.

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Summary of Significant Accounting Policies Narratives(Details) (USD $)	0 Months Ended	3 Months Ended		12 Months Ended	0 Months Ended
	Mar. 31, 2015	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Jun. 30, 2015	Jan. 01, 2015
Related Parties [Line Items]
Number of days after which we have not been paying debts or liabilities exceed assets FHFA must place us into receivership		60 days
Payments of cash dividends on senior preferred stock to Treasury	$ 1,900,000,000	$ 1,920,000,000	$ 7,191,000,000
Net worth	3,596,000,000	3,596,000,000		3,720,000,000
Minimum Days Past Due of Single Family Nonaccrual Loans 1				60 days
Deficit of core capital over statutory minimum capital requirement	142,200,000,000	142,200,000,000		142,200,000,000
Home Affordable Modification Program administrative expense reimbursements from Treasury and Freddie Mac		16,000,000	17,000,000
Income Taxes Paid		0us-gaap_IncomeTaxesPaid	425,000,000us-gaap_IncomeTaxesPaid
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees		382,000,000	322,000,000
Other expense		3,000,000us-gaap_OtherNoninterestExpense	131,000,000us-gaap_OtherNoninterestExpense
Basis points of each dollar of unpaid principal balance	0.042%	0.042%
Advisory Bulletin Impact for Loans Held for Investment						1,800,000,000
Advisory Bulletin Impact for Taxes and Insurance Receivables						724,000,000
Fee and other income		308,000,000	4,355,000,000
Mortgage Backed Private Label Securities and Repurchase Request Resolution Agreement [Member]
Related Parties [Line Items]
Fee and other income		0	4,100,000,000
Scenario, Forecast [Member]
Related Parties [Line Items]
Expected undeclared dividends payable on senior preferred stock for the next quarter					1,800,000,000
US Treasury [Member]
Related Parties [Line Items]
Aggregate funding received from US Treasury pursuant to the senior preferred stock purchase agreement	116,100,000,000	116,100,000,000
Initial aggregate liquidation preference of senior preferred stock held by US Treasury	1,000,000,000	1,000,000,000
Aggregate liquidation preference of senior preferred stock	117,100,000,000	117,100,000,000
Total available funding from US Treasury pursuant to the senior preferred stock agreement	117,600,000,000	117,600,000,000
Capital Reserve Amount, current year, Senior Preferred Stock Purchase Agreement, Amendment	1,800,000,000	1,800,000,000
Capital Reserve Amount, prior year, Senior Preferred Stock Purchase Agreement, Amendment				2,400,000,000
Annual Reduction of Capital Reserve Amount from 2013 to 2018, Senior Preferred Stock Purchase Agreement, Amendment	600,000,000	600,000,000
Percentage of common shares attributable to warrants issued to US Treasury as percentage to total diluted common shares	79.90%	79.90%
Income Taxes Paid			425,000,000
Proceeds from Income Tax Refunds		135,000,000
Percentage of initial principal loss US Treasury will bear for Temporary Credit and Liquidity Facilities and New Issue Bond Programs	35.00%	35.00%
Loss of principal or interest under Treasury's Temporary Credit and Liquidity Facility and New Issue Bond Programs	0	0
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees		382,000,000	322,000,000
US Treasury [Member] \| Capital Magnet Fund [Member]
Related Parties [Line Items]
Other expense		18,000,000
US Treasury [Member] \| Single-Family [Member]
Related Parties [Line Items]
Temporary Payroll Tax Cut Continuation Act of 2011 (“TCCA”) fees		382,000,000	322,000,000
Recognized TCCA fees that had not been remitted to Treasury as of period end	382,000,000	382,000,000
US Treasury [Member] \| Temporary Credit and Liquidity Facilities Program [Member]
Related Parties [Line Items]
Principal and interest outstanding	342,000,000	342,000,000		390,000,000
US Treasury [Member] \| New Issue Bond Program [Member]
Related Parties [Line Items]
Principal and interest outstanding	4,200,000,000	4,200,000,000		4,200,000,000
Freddie Mac [Member] \| Freddie Mac [Member]
Related Parties [Line Items]
Fair value of mortgage-related securities	7,000,000,000	7,000,000,000		6,900,000,000
Interest income recognized		61,000,000	78,000,000
Federal Housing Finance Agency [Member]
Related Parties [Line Items]
FHFA assessment fees		28,000,000	28,000,000
Common Securitization Solutions [Member]
Related Parties [Line Items]
Payments to Acquire Equity Method Investments		$ 13,000,000	$ 0