Mortgage Loans Aging (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	$ 34,149	[1]	$ 39,184	[1]
60 - 89 days delinquent	10,166	[1]	12,138	[1]
Seriously delinquent	64,253	[1],[2]	69,706	[1],[2]
Total delinquent	108,568	[1]	121,028	[1]
Current	2,944,549	[1]	2,943,641	[1]
Total recorded investment in loans	3,053,117	[1]	3,064,669	[1]
Recorded investment in loans 90 days or more delinquent and accruing interest	447	[1]	460	[1]
Recorded investment in nonaccrual loans	75,531	[1]	83,283	[1]
Primary [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total recorded investment in loans	2,647,074	[1],[3],[4],[5]	2,649,297	[1],[3],[4],[5]
Government [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total recorded investment in loans	47,900		48,600
Alt-A [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total recorded investment in loans	123,668	[1],[4],[5]	127,509	[1],[4],[5]
Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total recorded investment in loans	51,120	[1],[4],[5],[6]	53,291	[1],[4],[5],[6]
Single-Family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	34,104	[1]	39,125	[1]
60 - 89 days delinquent	10,166	[1]	12,138	[1]
Seriously delinquent	64,066	[1],[2]	69,520	[1],[2]
Total delinquent	108,336	[1]	120,783	[1]
Current	2,761,422	[1]	2,757,908	[1]
Total recorded investment in loans	2,869,758	[1]	2,878,691	[1]
Recorded investment in loans 90 days or more delinquent and accruing interest	447	[1]	460	[1]
Recorded investment in nonaccrual loans	73,691	[1]	81,074	[1]
Single-Family [Member] | Primary [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	27,858	[1],[3]	32,371	[1],[3]
60 - 89 days delinquent	8,090	[1],[3]	9,755	[1],[3]
Seriously delinquent	44,625	[1],[2],[3]	48,345	[1],[2],[3]
Total delinquent	80,573	[1],[3]	90,471	[1],[3]
Current	2,566,501	[1],[3]	2,558,826	[1],[3]
Total recorded investment in loans	2,647,074	[1],[3]	2,649,297	[1],[3]
Recorded investment in loans 90 days or more delinquent and accruing interest	65	[1],[3]	81	[1],[3]
Recorded investment in nonaccrual loans	52,614	[1],[3]	57,973	[1],[3]
Single-Family [Member] | Government [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	59	[1],[7]	66	[1],[7]
60 - 89 days delinquent	23	[1],[7]	32	[1],[7]
Seriously delinquent	348	[1],[2],[7]	346	[1],[2],[7]
Total delinquent	430	[1],[7]	444	[1],[7]
Current	47,466	[1],[7]	48,150	[1],[7]
Total recorded investment in loans	47,896	[1],[7]	48,594	[1],[7]
Recorded investment in loans 90 days or more delinquent and accruing interest	348	[1],[7]	346	[1],[7]
Recorded investment in nonaccrual loans	0	[1],[7]	0	[1],[7]
Single-Family [Member] | Alt-A [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	4,488	[1]	4,748	[1]
60 - 89 days delinquent	1,501	[1]	1,692	[1]
Seriously delinquent	14,227	[1],[2]	15,425	[1],[2]
Total delinquent	20,216	[1]	21,865	[1]
Current	103,452	[1]	105,644	[1]
Total recorded investment in loans	123,668	[1]	127,509	[1]
Recorded investment in loans 90 days or more delinquent and accruing interest	9	[1]	11	[1]
Recorded investment in nonaccrual loans	15,716	[1]	17,102	[1]
Single-Family [Member] | Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	1,699	[1],[6]	1,940	[1],[6]
60 - 89 days delinquent	552	[1],[6]	659	[1],[6]
Seriously delinquent	4,866	[1],[2],[6]	5,404	[1],[2],[6]
Total delinquent	7,117	[1],[6]	8,003	[1],[6]
Current	44,003	[1],[6]	45,288	[1],[6]
Total recorded investment in loans	51,120	[1],[6]	53,291	[1],[6]
Recorded investment in loans 90 days or more delinquent and accruing interest	25	[1],[6]	22	[1],[6]
Recorded investment in nonaccrual loans	5,361	[1],[6]	5,999	[1],[6]
Single-Family [Member] | Minimum [Member]
Table Footnote [Abstract]
Serious delinquency, days past due	90 days		90 days
Multifamily [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	45	[1],[8]	59	[1],[8]
Seriously delinquent	187	[1],[2],[8]	186	[1],[2],[8]
Total delinquent	232	[1],[8]	245	[1],[8]
Current	183,127	[1],[8]	185,733	[1],[8]
Total recorded investment in loans	183,359	[1],[8],[9]	185,978	[1],[8],[9]
Recorded investment in loans 90 days or more delinquent and accruing interest	0	[1],[8]	0	[1],[8]
Recorded investment in nonaccrual loans	$ 1,840	[1],[8]	$ 2,209	[1],[8]
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

[1] Recorded investment consists of unpaid principal balance, unamortized premiums, discounts and other cost basis adjustments, and accrued interest receivable.

[2] 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.

[3] Consists of mortgage loans that are not included in other loan classes.

[4] The aggregate estimated mark-to-market LTV ratio is based on the unpaid principal balance of the loan as of the end of each reported period divided by the estimated current value of the property, which we calculate using an internal valuation model that estimates periodic changes in home value.

[5] Excludes $47.9 billion and $48.6 billion as of March 31, 2014 and December 31, 2013, respectively, of mortgage loans guaranteed or insured, in whole or in part, by the U.S. government or one of its agencies that are not Alt-A loans. The segment class is primarily reverse mortgages for which we do not calculate an estimated mark-to-market LTV ratio.

[6] Includes loans with higher-risk characteristics, such as interest-only loans and negative-amortizing loans, that are neither government nor Alt-A.

[7] Consists 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. Primarily consists of reverse mortgages which, due to their nature, are not aged and are included in the current column.

[8] Multifamily loans 60-89 days delinquent are included in the seriously delinquent column.

[9] Pass (loan is current and adequately protected by the current financial strength and debt service capacity of the borrower); special mention (loan with signs of potential weakness); substandard (loan with a well defined weakness that jeopardizes the timely full repayment); and doubtful (loan with a weakness that makes collection or liquidation in full highly questionable and improbable based on existing conditions and values).