Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) (USD $) In Millions, except Per Share data	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Interest income:
Trading securities	$ 264	$ 330	$ 548	$ 645
Available-for-sale securities	1,152	1,389	2,365	2,862
Mortgage loans (includes $31,613 and $33,682, respectively, for the three months ended and $63,478 and $68,003, respectively, for the six months ended related to consolidated trusts)	35,333	37,632	70,923	75,251
Other	25	41	53	80
Total interest income	36,774	39,392	73,889	78,838
Interest expense:
Interest expense: Short-term debt (includes $2 and $3, respectively, for the three months ended and $5 for the six months ended, for both periods, related to consolidated trusts)	81	167	188	285
Interest expense: Long-term debt (includes $27,919 and $30,043, respectively, for the three months ended and $55,771 and $61,501, respectively, for the six months ended related to consolidated trusts)	31,721	35,018	63,769	71,557
Total interest expense	31,802	35,185	63,957	71,842
Net interest income	4,972	4,207	9,932	6,996
Provision for loan losses	(5,802)	(4,295)	(16,389)	(16,234)
Net interest income (loss) after provision for loan losses	(830)	(88)	(6,457)	(9,238)
Investment gains (losses), net	171	23	246	189
Other-than-temporary impairments	(28)	(48)	(85)	(234)
Noncredit portion of other-than-temporary impairments recognized in other comprehensive income	(28)	(89)	(15)	(139)
Net other-than-temporary impairments	(56)	(137)	(100)	(373)
Fair value gains (losses), net	(1,634)	303	(1,345)	(1,402)
Debt extinguishment gains (losses), net	(43)	(159)	(30)	(283)
Fee and other income (expense)	265	294	502	527
Non-interest income (loss)	(1,297)	324	(727)	(1,342)
Administrative expenses:
Salaries and employee benefits	310	324	630	648
Professional services	169	260	358	454
Occupancy expenses	43	40	85	81
Other administrative expenses	47	46	101	92
Total administrative expenses	569	670	1,174	1,275
Provision (benefit) for guaranty losses	735	69	702	33
Foreclosed property expense (income)	(478)	487	10	468
Other expenses (income)	32	224	384	454
Total expenses	858	1,450	2,270	2,230
Income (loss) before federal income taxes	(2,985)	(1,214)	(9,454)	(12,810)
Provision (benefit) for federal income taxes	(93)	9	(91)	(58)
Net income (loss)	(2,892)	(1,223)	(9,363)	(12,752)
Other comprehensive (loss) income:
Changes in unrealized losses on available-for-sale securities, net of reclassification adjustments and taxes	(1)	1,667	178	3,037
Other	3	3	5	5
Total other comprehensive income	2	1,670	183	3,042
Total comprehensive (loss) income	(2,890)	447	(9,180)	(9,710)
Less: Comprehensive (income) loss attributable to the noncontrolling interest	(1)	5	(1)	4
Total comprehensive (loss) income attributable to Fannie Mae	(2,891)	452	(9,181)	(9,706)
Net loss	(2,892)	(1,223)	(9,363)	(12,752)
Less: Net (income) loss attributable to the noncontrolling interest	(1)	5	(1)	4
Net income (loss) attributable to Fannie Mae	(2,893)	(1,218)	(9,364)	(12,748)
Preferred stock dividends	(2,282)	(1,907)	(4,498)	(3,434)
Net loss attributable to common stockholders	(5,175)	(3,125)	(13,862)	(16,182)
Loss per share - Basic (in dollars per share)	$ (0.90)	$ (0.55)	$ (2.43)	$ (2.84)
Loss per share - Diluted (in dollars per share)	$ (0.90)	$ (0.55)	$ (2.43)	$ (2.84)
Weighted-average common shares outstanding - Basic (in shares)	5,730	5,694	5,714	5,693
Weighted-average common shares outstanding - Diluted (in shares)	5,730	5,694	5,714	5,693
Of Consolidated Trusts [Member]
Interest income:
Mortgage loans (includes $31,613 and $33,682, respectively, for the three months ended and $63,478 and $68,003, respectively, for the six months ended related to consolidated trusts)	31,613	33,682	63,478	68,003
Interest expense:
Interest expense: Short-term debt (includes $2 and $3, respectively, for the three months ended and $5 for the six months ended, for both periods, related to consolidated trusts)	2	3	5	5
Interest expense: Long-term debt (includes $27,919 and $30,043, respectively, for the three months ended and $55,771 and $61,501, respectively, for the six months ended related to consolidated trusts)	$ 27,919	$ 30,043	$ 55,771	$ 61,501