Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
ASSETS
Restricted cash	$ 28,995	$ 67,919
Investments in securities:
Available-for-sale, at fair value	38,171	63,181
Mortgage loans:
Loans held for sale, at lower of cost or fair value	380	464
Accrued interest receivable, net	8,319	9,176
Cash pledged as collateral included in other assets	1,590	1,222
Liabilities:
Accrued interest payable	10,553	11,303
Other liabilities	15,441	14,378
Fannie Mae stockholders’ equity:
Senior preferred stock issued, shares	1,000,000	1,000,000
Senior preferred stock outstanding, shares	1,000,000	1,000,000
Preferred stock authorized	700,000,000	700,000,000
Preferred stock issued	555,374,922	555,374,922
Preferred Stock, Shares Outstanding	555,374,922	555,374,922
Common stock issued	1,308,762,703	1,308,762,703
Common stock outstanding	1,158,080,657	1,158,077,970
Treasury stock, shares	150,682,046	150,684,733
Fannie Mae [Member]
Liabilities:
Debt at fair value	1,308	793
Consolidated Trusts [Member]
ASSETS
Restricted cash	23,982	61,976
Investments in securities:
Available-for-sale, at fair value	998	935
Mortgage loans:
Loans held for sale, at lower of cost or fair value	31	72
Loans at fair value included in loans held for investment, at amortized cost	14,268	10,800
Loans pledged as collateral that may be sold or repledged included in loans held for investment, at amortized cost	442	943
Accrued interest receivable, net	7,271	7,567
Liabilities:
Accrued interest payable	8,276	8,645
Debt at fair value	14,976	11,647
Other liabilities	$ 488	$ 1,059