Mortgage Loans Loans in Mortgage Portfolio (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	$ 3,039,559	$ 2,978,693
Cost basis and fair value adjustments, net	30,527	29,508
Allowance for loan losses for loans held for investment	(43,846)	(58,795)	(72,156)	(61,556)
Total mortgage loans	3,026,240	2,949,406
Single-Family [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	2,855,668	2,790,276
Multifamily [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	183,891	188,417
Fannie Mae [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	314,286	370,741
Cost basis and fair value adjustments, net	(13,778)	(14,805)
Allowance for loan losses for loans held for investment	(40,521)	(50,519)	(57,309)	(48,530)
Total mortgage loans	259,987	305,417
Fannie Mae [Member] | Single-Family [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	276,644	309,277
Fannie Mae [Member] | Multifamily [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	37,642	61,464
Consolidated Trusts [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	2,725,273	2,607,952
Cost basis and fair value adjustments, net	44,305	44,313
Allowance for loan losses for loans held for investment	(3,325)	(8,276)	(14,847)	(13,026)
Total mortgage loans	2,766,253	2,643,989
Consolidated Trusts [Member] | Single-Family [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	2,579,024	2,480,999
Consolidated Trusts [Member] | Multifamily [Member]
Loans in Mortgage Portfolio [Line Items]
Unpaid principal balance of mortgage loans	$ 146,249	$ 126,953