Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
ASSETS
Cash and cash equivalents	$ 30,784		$ 21,117
Restricted cash (includes $26,804 and $61,976, respectively, related to consolidated trusts)	31,525		67,919
Federal funds sold and securities purchased under agreements to resell or similar arrangements	40,300		32,500
Investments in securities:
Trading, at fair value	32,860		40,695
Available-for-sale, at fair value (includes $911 and $935, respectively, related to consolidated trusts)	41,000		63,181
Total investments in securities	73,860		103,876
Mortgage loans:
Loans held for sale, at lower of cost or fair value (includes $41 and $72, respectively, related to consolidated trusts)	998		464
Loans held for investment, at amortized cost (includes $13,877 and $10,800, respectively, at fair value and loans pledged as collateral that may be sold or repledged of $477 and $943, respectively, related to consolidated trusts)	3,057,351		3,007,737
Allowance for loan losses	(45,169)		(58,795)
Total loans held for investment, net of allowance	3,012,182		2,948,942
Total mortgage loans	3,013,180		2,949,406
Accrued interest receivable, net (includes $7,568 and $7,567, respectively, related to consolidated trusts)	8,696		9,176
Acquired property, net	11,380	[1]	10,489
Deferred tax assets, net	48,256		0
Other assets (includes cash pledged as collateral of $2,635 and $1,222, respectively)	23,241		27,939
Total assets	3,281,222		3,222,422
Liabilities:
Accrued interest payable (includes $8,234 and $8,645, respectively, related to consolidated trusts)	10,769		11,303
Other liabilities (includes $501 and $1,059, respectively, related to consolidated trusts)	18,715		14,378
Total liabilities	3,269,605		3,215,198
Commitments and contingencies (Note 17)
Fannie Mae stockholders' equity (deficit):
Senior preferred stock, 1,000,000 shares issued and outstanding	117,149		117,149
Preferred stock, 700,000,000 shares are authorized—555,374,922 shares issued and outstanding, respectively	19,130		19,130
Common stock, no par value, no maximum authorization—1,308,762,703 shares issued, respectively, 1,158,080,657 and 1,158,077,970 shares outstanding, respectively	687		687
Accumulated deficit	(119,067)		(122,766)
Accumulated other comprehensive income (loss)	1,070		384
Treasury stock, at cost, 150,684,733 shares, respectively	(7,401)		(7,401)
Total Fannie Mae stockholders' equity (deficit)	11,568		7,183
Noncontrolling interest	49		41
Total equity (deficit) [See Note 1: Impact of U.S. government support and Earnings (loss) per share for information on our dividend obligation to Treasury]	11,617		7,224
Total liabilities and equity (deficit)	3,281,222		3,222,422
Fannie Mae [Member]
Mortgage loans:
Loans held for investment, at amortized cost (includes $13,877 and $10,800, respectively, at fair value and loans pledged as collateral that may be sold or repledged of $477 and $943, respectively, related to consolidated trusts)	313,267		355,544
Allowance for loan losses	(41,345)		(50,519)
Total mortgage loans	272,879		305,417
Liabilities:
Debt (includes $684 and $793, respectively, of debt of Fannie Mae and $14,414 and $11,647, respectively, of debt of consolidated trusts, at fair value)	565,110		615,864
Consolidated Trusts [Member]
ASSETS
Restricted cash (includes $26,804 and $61,976, respectively, related to consolidated trusts)	26,804		61,976
Investments in securities:
Available-for-sale, at fair value (includes $911 and $935, respectively, related to consolidated trusts)	911		935
Mortgage loans:
Loans held for sale, at lower of cost or fair value (includes $41 and $72, respectively, related to consolidated trusts)	41		72
Loans held for investment, at amortized cost (includes $13,877 and $10,800, respectively, at fair value and loans pledged as collateral that may be sold or repledged of $477 and $943, respectively, related to consolidated trusts)	2,744,084		2,652,193
Allowance for loan losses	(3,824)		(8,276)
Total mortgage loans	2,740,301		2,643,989
Accrued interest receivable, net (includes $7,568 and $7,567, respectively, related to consolidated trusts)	7,568		7,567
Liabilities:
Accrued interest payable (includes $8,234 and $8,645, respectively, related to consolidated trusts)	8,234		8,645
Debt (includes $684 and $793, respectively, of debt of Fannie Mae and $14,414 and $11,647, respectively, of debt of consolidated trusts, at fair value)	2,675,011		2,573,653
Other liabilities (includes $501 and $1,059, respectively, related to consolidated trusts)	$ 501		$ 1,059

[1] Includes valuation allowance of $564 million and $664 million as of September 30, 2013 and 2012, respectively.