Mortgage Loans TDR (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014 contracts		Mar. 31, 2013 contracts
Financing Receivable, Modifications [Line Items]
Average term extension of a single-family modified loan	159 months		148 months
Average interest rate reduction of a single-family modified loan	1.23%		1.81%
Number of loans troubled debt restructurings activity	34,344		47,516
Recorded investment troubled debt restructurings activity	$ 5,111	[1]	$ 7,363	[1]
Number of loans troubled debt restructurings subsequent default	10,568		15,587
Recorded investment troubled debt restructurings subsequent default	1,701	[2]	2,555	[2]
Single-Family [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity	34,338		47,508
Recorded investment troubled debt restructurings activity	5,077	[1]	7,330	[1]
Number of loans troubled debt restructurings subsequent default	10,564		15,584
Recorded investment troubled debt restructurings subsequent default	1,687	[2]	2,540	[2]
Single-Family [Member] | Primary [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity	28,842	[3]	38,251	[3]
Recorded investment troubled debt restructurings activity	4,110	[1],[3]	5,644	[1],[3]
Number of loans troubled debt restructurings subsequent default	8,598	[3]	12,060	[3]
Recorded investment troubled debt restructurings subsequent default	1,310	[2],[3]	1,867	[2],[3]
Single-Family [Member] | Government [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity	62	[4]	90	[4]
Recorded investment troubled debt restructurings activity	8	[1],[4]	11	[1],[4]
Number of loans troubled debt restructurings subsequent default	18	[4]	29	[4]
Recorded investment troubled debt restructurings subsequent default	2	[2],[4]	4	[2],[4]
Single-Family [Member] | Alt-A [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity	4,396		7,110
Recorded investment troubled debt restructurings activity	740	[1]	1,223	[1]
Number of loans troubled debt restructurings subsequent default	1,444		2,672
Recorded investment troubled debt restructurings subsequent default	260	[2]	484	[2]
Single-Family [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity	1,038	[5]	2,057	[5]
Recorded investment troubled debt restructurings activity	219	[1],[5]	452	[1],[5]
Number of loans troubled debt restructurings subsequent default	504	[5]	823	[5]
Recorded investment troubled debt restructurings subsequent default	115	[2],[5]	185	[2],[5]
Multifamily [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity	6		8
Recorded investment troubled debt restructurings activity	34	[1]	33	[1]
Number of loans troubled debt restructurings subsequent default	4		3
Recorded investment troubled debt restructurings subsequent default	$ 14	[2]	$ 15	[2]

[1] Recorded investment consists of unpaid principal balance, unamortized premiums, discounts and other cost basis adjustments, and accrued interest receivable. 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 amounts represent recorded investment post-modification.

[2] Recorded investment consists of unpaid principal balance, unamortized premiums, discounts and other cost basis adjustments, and accrued interest receivable. Represents our recorded investment in the loan at time of payment default.

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

[4] 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.

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