Mortgage Loans TDR (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014 contracts		Jun. 30, 2013 contracts		Jun. 30, 2014 contracts		Jun. 30, 2013 contracts
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity	29,578		38,227		63,922		85,743
Recorded investment troubled debt restructurings activity	$ 4,374	[1]	$ 6,295	[1]	$ 9,485	[1]	$ 13,658	[1]
Number of loans troubled debt restructurings subsequent default	10,025		14,790		20,593		30,377
Recorded investment troubled debt restructurings subsequent default	1,596	[2]	2,419	[2]	3,297	[2]	4,974	[2]
Single-Family [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity	29,575		38,210		63,913		85,718
Recorded investment troubled debt restructurings activity	4,370	[1]	6,160	[1]	9,447	[1]	13,490	[1]
Number of loans troubled debt restructurings subsequent default	10,024		14,787		20,588		30,371
Recorded investment troubled debt restructurings subsequent default	1,593	[2]	2,414	[2]	3,280	[2]	4,954	[2]
Single-Family [Member] | Primary [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity	24,932	[3]	31,304	[3]	53,774	[3]	69,555	[3]
Recorded investment troubled debt restructurings activity	3,564	[1],[3]	4,833	[1],[3]	7,674	[1],[3]	10,477	[1],[3]
Number of loans troubled debt restructurings subsequent default	8,190	[3]	11,320	[3]	16,788	[3]	23,380	[3]
Recorded investment troubled debt restructurings subsequent default	1,251	[2],[3]	1,749	[2],[3]	2,561	[2],[3]	3,616	[2],[3]
Single-Family [Member] | Government [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity	111	[4]	90	[4]	173	[4]	180	[4]
Recorded investment troubled debt restructurings activity	13	[1],[4]	10	[1],[4]	21	[1],[4]	21	[1],[4]
Number of loans troubled debt restructurings subsequent default	18	[4]	31	[4]	36	[4]	60	[4]
Recorded investment troubled debt restructurings subsequent default	1	[2],[4]	4	[2],[4]	3	[2],[4]	8	[2],[4]
Single-Family [Member] | Alt-A [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity	3,660		5,175		8,056		12,285
Recorded investment troubled debt restructurings activity	614	[1]	947	[1]	1,354	[1]	2,170	[1]
Number of loans troubled debt restructurings subsequent default	1,396		2,584		2,840		5,256
Recorded investment troubled debt restructurings subsequent default	252	[2]	466	[2]	512	[2]	950	[2]
Single-Family [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity	872	[5]	1,641	[5]	1,910	[5]	3,698	[5]
Recorded investment troubled debt restructurings activity	179	[1],[5]	370	[1],[5]	398	[1],[5]	822	[1],[5]
Number of loans troubled debt restructurings subsequent default	420	[5]	852	[5]	924	[5]	1,675	[5]
Recorded investment troubled debt restructurings subsequent default	89	[2],[5]	195	[2],[5]	204	[2],[5]	380	[2],[5]
Multifamily [Member]
Financing Receivable, Modifications [Line Items]
Number of loans troubled debt restructurings activity	3		17		9		25
Recorded investment troubled debt restructurings activity	4	[1]	135	[1]	38	[1]	168	[1]
Number of loans troubled debt restructurings subsequent default	1		3		5		6
Recorded investment troubled debt restructurings subsequent default	$ 3	[2]	$ 5	[2]	$ 17	[2]	$ 20	[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.