Mortgage Loans Aging (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2014		Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	$ 35,149	[1]	$ 39,184	[1]
60 - 89 days delinquent	10,378	[1]	12,138	[1]
Seriously delinquent	59,567	[1],[2]	69,706	[1],[2]
Total delinquent	105,094	[1]	121,028	[1]
Current	2,932,205	[1]	2,943,641	[1]
Total recorded investment in loans	3,037,299	[1]	3,064,669	[1]
Recorded investment in loans 90 days or more delinquent and accruing interest	414	[1]	460	[1]
Recorded investment in nonaccrual loans	70,882	[1]	83,283	[1]
Primary [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total recorded investment in loans	2,638,966	[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	47,000		48,600
Alt-A [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total recorded investment in loans	119,532	[1],[4],[5]	127,509	[1],[4],[5]
Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total recorded investment in loans	48,852	[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	35,090	[1]	39,125	[1]
60 - 89 days delinquent	10,378	[1]	12,138	[1]
Seriously delinquent	59,395	[1],[2]	69,520	[1],[2]
Total delinquent	104,863	[1]	120,783	[1]
Current	2,749,490	[1]	2,757,908	[1]
Total recorded investment in loans	2,854,353	[1]	2,878,691	[1]
Recorded investment in loans 90 days or more delinquent and accruing interest	414	[1]	460	[1]
Recorded investment in nonaccrual loans	69,265	[1]	81,074	[1]
Single-Family [Member] | Minimum [Member]
Table Footnote [Abstract]
Serious delinquency, days past due	90 days		90 days
Single-Family [Member] | Primary [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	29,122	[1],[3]	32,371	[1],[3]
60 - 89 days delinquent	8,323	[1],[3]	9,755	[1],[3]
Seriously delinquent	41,458	[1],[2],[3]	48,345	[1],[2],[3]
Total delinquent	78,903	[1],[3]	90,471	[1],[3]
Current	2,560,063	[1],[3]	2,558,826	[1],[3]
Total recorded investment in loans	2,638,966	[1],[3]	2,649,297	[1],[3]
Recorded investment in loans 90 days or more delinquent and accruing interest	57	[1],[3]	81	[1],[3]
Recorded investment in nonaccrual loans	49,689	[1],[3]	57,973	[1],[3]
Single-Family [Member] | Government [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	63	[1],[7]	66	[1],[7]
60 - 89 days delinquent	24	[1],[7]	32	[1],[7]
Seriously delinquent	330	[1],[2],[7]	346	[1],[2],[7]
Total delinquent	417	[1],[7]	444	[1],[7]
Current	46,586	[1],[7]	48,150	[1],[7]
Total recorded investment in loans	47,003	[1],[7]	48,594	[1],[7]
Recorded investment in loans 90 days or more delinquent and accruing interest	330	[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	4,227	[1]	4,748	[1]
60 - 89 days delinquent	1,469	[1]	1,692	[1]
Seriously delinquent	13,220	[1],[2]	15,425	[1],[2]
Total delinquent	18,916	[1]	21,865	[1]
Current	100,616	[1]	105,644	[1]
Total recorded investment in loans	119,532	[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	14,677	[1]	17,102	[1]
Single-Family [Member] | Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	1,678	[1],[6]	1,940	[1],[6]
60 - 89 days delinquent	562	[1],[6]	659	[1],[6]
Seriously delinquent	4,387	[1],[2],[6]	5,404	[1],[2],[6]
Total delinquent	6,627	[1],[6]	8,003	[1],[6]
Current	42,225	[1],[6]	45,288	[1],[6]
Total recorded investment in loans	48,852	[1],[6]	53,291	[1],[6]
Recorded investment in loans 90 days or more delinquent and accruing interest	18	[1],[6]	22	[1],[6]
Recorded investment in nonaccrual loans	4,899	[1],[6]	5,999	[1],[6]
Multifamily [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days delinquent	59	[1],[8]	59	[1],[8]
Seriously delinquent	172	[1],[2],[8]	186	[1],[2],[8]
Total delinquent	231	[1],[8]	245	[1],[8]
Current	182,715	[1],[8]	185,733	[1],[8]
Total recorded investment in loans	182,946	[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	$ 1,617	[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		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 $47.0 billion and $48.6 billion as of June 30, 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 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).