Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
ASSETS
Cash and cash equivalents	$ 23,413		$ 21,117
Restricted cash (includes $51,847 and $61,976, respectively, related to consolidated trusts)	57,231		67,919
Federal funds sold and securities purchased under agreements to resell or similar arrangements	79,350		32,500
Investments in securities:
Trading, at fair value	52,391		40,695
Available-for-sale, at fair value (includes $762 and $935, respectively, related to consolidated trusts)	60,329		63,181
Total investments in securities	112,720		103,876
Mortgage loans:
Loans held for sale, at lower of cost or fair value (includes $104 and $72, respectively, related to consolidated trusts)	455		464
Loans held for investment, at amortized cost (includes $12,602 and $10,800, respectively, at fair value and loans pledged as collateral that may be sold or repledged of $859 and $943, respectively, related to consolidated trusts)	3,014,642		3,007,737
Allowance for loan losses	(56,461)		(58,795)
Total loans held for investment, net of allowance	2,958,181		2,948,942
Total mortgage loans	2,958,636		2,949,406
Accrued interest receivable, net (includes $7,801 and $7,567, respectively, related to consolidated trusts)	9,160		9,176
Acquired property, net	10,149	[1]	10,489
Deferred tax assets, net	49,738		0
Other assets (includes cash pledged as collateral of $1,289 and $1,222, respectively)	20,278		27,939
Total assets	3,320,675		3,222,422
Liabilities:
Accrued interest payable (includes $8,435 and $8,645, respectively, related to consolidated trusts)	11,163		11,303
Federal funds purchased and securities sold under agreements to repurchase	218	[2]	0	[2]
Other liabilities (includes $406 and $1,059, respectively, related to consolidated trusts)	14,383		14,378
Total liabilities	3,258,307		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, 1,158,077,970 shares outstanding, respectively	687		687
Accumulated deficit	(68,276)		(122,766)
Accumulated other comprehensive income (loss)	1,038		384
Treasury stock, at cost, 150,684,733 shares, respectively	(7,401)		(7,401)
Total Fannie Mae stockholders' equity (deficit)	62,327		7,183
Noncontrolling interest	41		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]	62,368		7,224
Total liabilities and equity (deficit)	3,320,675		3,222,422
Fannie Mae [Member]
Mortgage loans:
Loans held for investment, at amortized cost (includes $12,602 and $10,800, respectively, at fair value and loans pledged as collateral that may be sold or repledged of $859 and $943, respectively, related to consolidated trusts)	336,585		355,544
Allowance for loan losses	(49,553)		(50,519)
Total mortgage loans	287,383		305,417
Liabilities:
Debt (includes $770 and $793, respectively, of debt of Fannie Mae and $13,345 and $11,647, respectively, of debt of consolidated trusts, at fair value)	630,260		615,864
Consolidated Trusts [Member]
ASSETS
Restricted cash (includes $51,847 and $61,976, respectively, related to consolidated trusts)	51,847		61,976
Investments in securities:
Available-for-sale, at fair value (includes $762 and $935, respectively, related to consolidated trusts)	762		935
Mortgage loans:
Loans held for sale, at lower of cost or fair value (includes $104 and $72, respectively, related to consolidated trusts)	104		72
Loans held for investment, at amortized cost (includes $12,602 and $10,800, respectively, at fair value and loans pledged as collateral that may be sold or repledged of $859 and $943, respectively, related to consolidated trusts)	2,678,057		2,652,193
Allowance for loan losses	(6,908)		(8,276)
Total mortgage loans	2,671,253		2,643,989
Accrued interest receivable, net (includes $7,801 and $7,567, respectively, related to consolidated trusts)	7,801		7,567
Liabilities:
Accrued interest payable (includes $8,435 and $8,645, respectively, related to consolidated trusts)	8,435		8,645
Debt (includes $770 and $793, respectively, of debt of Fannie Mae and $13,345 and $11,647, respectively, of debt of consolidated trusts, at fair value)	2,602,283		2,573,653
Other liabilities (includes $406 and $1,059, respectively, related to consolidated trusts)	$ 406		$ 1,059

[1] Includes valuation allowance of $570 million and $790 million as of March 31, 2013 and 2012, respectively.

[2] Securities sold under agreements to repurchase represents agreements to repurchase securities for a specified price, with repayment generally occurring on the following day.