Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
ASSETS
Cash and cash equivalents	$ 24,718		$ 21,117
Restricted cash (includes $48,774 and $61,976, respectively, related to consolidated trusts)	53,930		67,919
Federal funds sold and securities purchased under agreements to resell or similar arrangements	37,800		32,500
Investments in securities:
Trading, at fair value	40,189		40,695
Available-for-sale, at fair value (includes $665 and $935, respectively, related to consolidated trusts)	55,536		63,181
Total investments in securities	95,725		103,876
Mortgage loans:
Loans held for sale, at lower of cost or fair value (includes $101 and $72, respectively, related to consolidated trusts)	545		464
Loans held for investment, at amortized cost (includes $13,770 and $10,800, respectively, at fair value and loans pledged as collateral that may be sold or repledged of $524 and $943, respectively, related to consolidated trusts)	3,025,152		3,007,737
Allowance for loan losses	(49,643)		(58,795)
Total loans held for investment, net of allowance	2,975,509		2,948,942
Total mortgage loans	2,976,054		2,949,406
Accrued interest receivable, net (includes $7,725 and $7,567, respectively, related to consolidated trusts)	8,997		9,176
Acquired property, net	10,266	[1]	10,489
Deferred tax assets, net	48,679		0
Other assets (includes cash pledged as collateral of $981 and $1,222, respectively)	24,496		27,939
Total assets	3,280,665		3,222,422
Liabilities:
Accrued interest payable (includes $8,275 and $8,645, respectively, related to consolidated trusts)	10,613		11,303
Other liabilities (includes $366 and $1,059, respectively, related to consolidated trusts)	16,274		14,378
Total liabilities	3,267,422		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	(117,561)		(122,766)
Accumulated other comprehensive income (loss)	1,204		384
Treasury stock, at cost, 150,684,733 shares, respectively	(7,401)		(7,401)
Total Fannie Mae stockholders' equity (deficit)	13,208		7,183
Noncontrolling interest	35		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]	13,243		7,224
Total liabilities and equity (deficit)	3,280,665		3,222,422
Fannie Mae [Member]
Mortgage loans:
Loans held for investment, at amortized cost (includes $13,770 and $10,800, respectively, at fair value and loans pledged as collateral that may be sold or repledged of $524 and $943, respectively, related to consolidated trusts)	328,573		355,544
Allowance for loan losses	(44,825)		(50,519)
Total mortgage loans	284,192		305,417
Liabilities:
Debt (includes $720 and $793, respectively, of debt of Fannie Mae and $14,601 and $11,647, respectively, of debt of consolidated trusts, at fair value)	603,240		615,864
Consolidated Trusts [Member]
ASSETS
Restricted cash (includes $48,774 and $61,976, respectively, related to consolidated trusts)	48,774		61,976
Investments in securities:
Available-for-sale, at fair value (includes $665 and $935, respectively, related to consolidated trusts)	665		935
Mortgage loans:
Loans held for sale, at lower of cost or fair value (includes $101 and $72, respectively, related to consolidated trusts)	101		72
Loans held for investment, at amortized cost (includes $13,770 and $10,800, respectively, at fair value and loans pledged as collateral that may be sold or repledged of $524 and $943, respectively, related to consolidated trusts)	2,696,579		2,652,193
Allowance for loan losses	(4,818)		(8,276)
Total mortgage loans	2,691,862		2,643,989
Accrued interest receivable, net (includes $7,725 and $7,567, respectively, related to consolidated trusts)	7,725		7,567
Liabilities:
Accrued interest payable (includes $8,275 and $8,645, respectively, related to consolidated trusts)	8,275		8,645
Debt (includes $720 and $793, respectively, of debt of Fannie Mae and $14,601 and $11,647, respectively, of debt of consolidated trusts, at fair value)	2,637,295		2,573,653
Other liabilities (includes $366 and $1,059, respectively, related to consolidated trusts)	$ 366		$ 1,059

[1] Includes valuation allowance of $540 million and $648 million as of June 30, 2013 and 2012, respectively.