Mortgage Loans Individually Impaired Loans - 2 (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	$ 178,036,000,000		$ 167,089,000,000		$ 147,448,000,000
Individually impaired loans with related allowance recorded: total interest income recognized	6,011,000,000	[1]	5,705,000,000	[1]	5,267,000,000	[1]
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	791,000,000		872,000,000		1,014,000,000
Individually impaired loans with no related allowance recorded: average recorded investment	16,376,000,000	[2]	12,389,000,000	[2]	10,127,000,000	[2]
Individually impaired loans with no related allowance recorded: total interest income recognized	1,920,000,000	[1],[2]	1,486,000,000	[1],[2]	923,000,000	[1],[2]
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	292,000,000	[2]	312,000,000	[2]	294,000,000	[2]
Individually impaired loans: average recorded investment	194,412,000,000	[3]	179,478,000,000	[3]	157,575,000,000	[3]
Individually impaired loans: total interest income recognized	7,931,000,000	[1],[3]	7,191,000,000	[1],[3]	6,190,000,000	[1],[3]
Individually impaired loans: interest income recognized on a cash basis	1,083,000,000	[3]	1,184,000,000	[3]	1,308,000,000	[3]
Primary [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	124,659,000,000	[4]	115,767,000,000	[4]	100,797,000,000	[4]
Individually impaired loans with related allowance recorded: total interest income recognized	4,351,000,000	[1],[4]	4,077,000,000	[1],[4]	3,735,000,000	[1],[4]
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	603,000,000	[4]	654,000,000	[4]	733,000,000	[4]
Individually impaired loans with no related allowance recorded: average recorded investment	11,442,000,000	[2],[4]	8,264,000,000	[2],[4]	6,884,000,000	[2],[4]
Individually impaired loans with no related allowance recorded: total interest income recognized	1,369,000,000	[1],[2],[4]	1,075,000,000	[1],[2],[4]	606,000,000	[1],[2],[4]
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	227,000,000	[2],[4]	231,000,000	[2],[4]	204,000,000	[2],[4]
Government [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	213,000,000	[5]	216,000,000	[5]	229,000,000	[5]
Individually impaired loans with related allowance recorded: total interest income recognized	11,000,000	[1],[5]	11,000,000	[1],[5]	12,000,000	[1],[5]
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	0	[5]	0	[5]	0	[5]
Individually impaired loans with no related allowance recorded: average recorded investment	112,000,000	[2],[5]	78,000,000	[2],[5]	12,000,000	[2],[5]
Individually impaired loans with no related allowance recorded: total interest income recognized	8,000,000	[1],[2],[5]	7,000,000	[1],[2],[5]	7,000,000	[1],[2],[5]
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	0	[2],[5]	0	[2],[5]	0	[2],[5]
Alt-A [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	35,075,000,000		32,978,000,000		29,561,000,000
Individually impaired loans with related allowance recorded: total interest income recognized	1,096,000,000	[1]	1,048,000,000	[1]	982,000,000	[1]
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	135,000,000		151,000,000		186,000,000
Individually impaired loans with no related allowance recorded: average recorded investment	2,207,000,000	[2]	1,811,000,000	[2]	1,771,000,000	[2]
Individually impaired loans with no related allowance recorded: total interest income recognized	329,000,000	[1],[2]	253,000,000	[1],[2]	205,000,000	[1],[2]
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	45,000,000	[2]	55,000,000	[2]	63,000,000	[2]
Other [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	15,537,000,000	[6]	15,593,000,000	[6]	14,431,000,000	[6]
Individually impaired loans with related allowance recorded: total interest income recognized	425,000,000	[1],[6]	444,000,000	[1],[6]	435,000,000	[1],[6]
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	52,000,000	[6]	65,000,000	[6]	90,000,000	[6]
Individually impaired loans with no related allowance recorded: average recorded investment	752,000,000	[2],[6]	455,000,000	[2],[6]	467,000,000	[2],[6]
Individually impaired loans with no related allowance recorded: total interest income recognized	117,000,000	[1],[2],[6]	95,000,000	[1],[2],[6]	57,000,000	[1],[2],[6]
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	17,000,000	[2],[6]	24,000,000	[2],[6]	19,000,000	[2],[6]
Single-Family [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	175,484,000,000		164,554,000,000		145,018,000,000
Individually impaired loans with related allowance recorded: total interest income recognized	5,883,000,000	[1]	5,580,000,000	[1]	5,164,000,000	[1]
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	790,000,000		870,000,000		1,009,000,000
Individually impaired loans with no related allowance recorded: average recorded investment	14,513,000,000	[2]	10,608,000,000	[2]	9,134,000,000	[2]
Individually impaired loans with no related allowance recorded: total interest income recognized	1,823,000,000	[1],[2]	1,430,000,000	[1],[2]	875,000,000	[1],[2]
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	289,000,000	[2]	310,000,000	[2]	286,000,000	[2]
Individually impaired loans: total interest income recognized	7,700,000,000		7,000,000,000		6,000,000,000
Individually impaired loans: contractual interest income	5,700,000,000		5,300,000,000		4,500,000,000
Individually impaired loans: effective yield adjustments	2,000,000,000		1,700,000,000		1,600,000,000
Multifamily [Member]
Financing Receivable, Impaired [Line Items]
Individually impaired loans with related allowance recorded: average recorded investment	2,552,000,000		2,535,000,000		2,430,000,000
Individually impaired loans with related allowance recorded: total interest income recognized	128,000,000	[1]	125,000,000	[1]	103,000,000	[1]
Individually impaired loans with related allowance recorded: interest income recognized on a cash basis	1,000,000		2,000,000		5,000,000
Individually impaired loans with no related allowance recorded: average recorded investment	1,863,000,000	[2]	1,781,000,000	[2]	993,000,000	[2]
Individually impaired loans with no related allowance recorded: total interest income recognized	97,000,000	[1],[2]	56,000,000	[1],[2]	48,000,000	[1],[2]
Individually impaired loans with no related allowance recorded: interest income recognized on a cash basis	$ 3,000,000	[2]	$ 2,000,000	[2]	$ 8,000,000	[2]

[1] Total single-family interest income recognized of $7.7 billion for the year ended December 31, 2013 consists of $5.7 billion of contractual interest and $2.0 billion of effective yield adjustments. Total single-family interest income recognized of $7.0 billion for the year ended December 31, 2012 consists of $5.3 billion of contractual interest and $1.7 billion of effective yield adjustments. Total single-family interest income recognized of $6.0 billion for the year ended December 31, 2011 consists of $4.5 billion of contractual interest and $1.6 billion of effective yield adjustments.

[2] The discounted cash flows or collateral value equals or exceeds the carrying value of the loan and, as such, no valuation allowance is required.

[3] Includes single-family loans restructured in a TDR with a recorded investment of $187.6 billion, $193.4 billion and $161.9 billion as of December 31, 2013, 2012 and 2011, respectively. Includes multifamily loans restructured in a TDR with a recorded investment of $911 million, $1.1 billion and $956 million as of December 31, 2013, 2012 and 2011, respectively.

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

[5] 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.

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