Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (Unaudited) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011		Sep. 30, 2012	Sep. 30, 2011
Interest income:
Trading securities	$ 234	$ 274		$ 756	$ 822
Available-for-sale securities	789	1,160		2,551	3,525
Mortgage loans (includes $27,057 and $30,633, respectively, for the three months ended and $84,482 and $94,111, respectively, for the nine months ended related to consolidated trusts)	30,593	34,334		95,186	105,257
Other	53	26		131	79
Total interest income	31,669	35,794		98,624	109,683
Interest expense:
Short-term debt	38	66		112	254
Long-term debt (includes $23,395 and $27,157, respectively, for the three months ended and $73,469 and $82,928, respectively, for the nine months ended related to consolidated trusts)	26,314	30,542		82,570	94,311
Total interest expense	26,352	30,608		82,682	94,565
Net interest income	5,317	5,186		15,942	15,118
Benefit (provision) for credit losses	(2,079)	(4,151)	[1]	(1,038)	(21,242)	[1]
Net interest income (loss) after benefit (provision) for credit losses	3,238	1,035		14,904	(6,124)
Investment gains, net	134	73		381	319
Other-than-temporary impairments	(17)	(232)		(293)	(317)
Noncredit portion of other-than-temporary impairments recognized in other comprehensive income	(21)	(30)		(408)	(45)
Net other-than-temporary impairments	(38)	(262)		(701)	(362)
Fair value gains (losses), net	(1,020)	(4,525)		(3,186)	(5,870)
Debt extinguishment (losses) gains, net	(54)	(119)		(181)	(149)
Fee and other income (expense)	378	291		1,148	793
Non-interest income (loss)	(600)	(4,542)		(2,539)	(5,269)
Administrative expenses:
Salaries and employee benefits	294	323		892	953
Professional services	195	173		542	531
Occupancy expenses	48	46		139	131
Other administrative expenses	51	49		146	150
Total administrative expenses	588	591		1,719	1,765
Foreclosed property expense (income)	(48)	733		221	743
Other expenses	285	254		775	638
Total expenses	825	1,578		2,715	3,146
Income (loss) before federal income taxes	1,813	(5,085)		9,650	(14,539)
(Provision) benefit for federal income taxes	0	0		0	91
Net income (loss)	1,813	(5,085)		9,650	(14,448)
Other comprehensive income (loss):
Changes in unrealized gains (losses) on available-for-sale securities, net of reclassification adjustments and taxes	741	(198)		1,416	(20)
Other	5	1		20	6
Total other comprehensive income (loss)	746	(197)		1,436	(14)
Total comprehensive income (loss)	2,559	(5,282)		11,086	(14,462)
Less: Comprehensive (income) loss attributable to the noncontrolling interest	8	0		4	(1)
Total comprehensive income (loss) attributable to Fannie Mae	2,567	(5,282)		11,090	(14,463)
Net income (loss)	1,813	(5,085)		9,650	(14,448)
Less: Net (income) loss attributable to the noncontrolling interest	8	0		4	(1)
Net (loss) income attributable to Fannie Mae	1,821	(5,085)		9,654	(14,449)
Preferred stock dividends	(2,929)	(2,494)		(8,675)	(6,992)
Net income (loss) attributable to common stockholders	$ (1,108)	$ (7,579)		$ 979	$ (21,441)
Earnings (loss) per share, Basic	$ (0.19)	$ (1.32)		$ 0.17	$ (3.74)
Earnings (loss) per share, Diluted	$ (0.19)	$ (1.32)		$ 0.17	$ (3.74)
Weighted-average common shares outstanding, Basic	5,762	5,760		5,762	5,730
Weighted-average common shares outstanding, Diluted	5,762	5,760		5,893	5,730

[1] Prior period amounts have been reclassified to conform to the current period presentation.