Consolidated Statements of Operations and Comprehensive Income (Loss) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Interest income:
Trading securities	$ 989		$ 1,087		$ 1,251
Available-for-sale securities	3,299		3,277		5,290
Mortgage loans (includes $110,451, $123,633, and $132,591, respectively, related to consolidated trusts)	124,706		138,462		147,583
Other	196		117		146
Total interest income	129,190		142,943		154,270
Interest expense:
Short-term debt	152		310		631
Long-term debt (includes $95,612, $108,641, and $118,373, respectively, related to consolidated trusts)	107,537		123,352		137,230
Total interest expense	107,689		123,662		137,861
Net interest income	21,501		19,281		16,409
Benefit (provision) for credit losses	852		(26,718)		(24,896)
Net interest income (loss) after benefit (provision) for credit losses	22,353		(7,437)		(8,487)
Investment gains, net	487		506		346
Other-than-temporary impairments	(311)		(614)		(694)
Noncredit portion of other-than-temporary impairments recognized in other comprehensive income (loss)	(402)		306		(28)
Net other-than-temporary impairments	(713)		(308)		(722)	[1]
Fair value losses, net	(2,977)		(6,621)		(511)
Debt extinguishment losses, net	(244)		(232)		(568)
Fee and other income	1,487		1,163		1,084
Non-interest loss	(1,960)		(5,492)		(371)
Administrative expenses:
Salaries and employee benefits	1,195		1,236		1,277
Professional services	766		736		942
Occupancy expenses	188		179		170
Other administrative expenses	218		219		208
Total administrative expenses	2,367		2,370		2,597
Foreclosed property (income) expense	(254)		780		1,718
Other expenses	1,060		866		927
Total expenses	3,173		4,016		5,242
Income (loss) before federal income taxes	17,220		(16,945)		(14,100)
Benefit for federal income taxes	0		90		82
Net income (loss)	17,220		(16,855)		(14,018)
Other comprehensive income (loss):
Changes in unrealized gains on available-for-sale securities, net of reclassification adjustments and taxes	1,735		622		3,504
Other	(116)		(175)		(60)
Total other comprehensive income	1,619		447		3,444
Total comprehensive income (loss)	18,839		(16,408)		(10,574)
Less: Comprehensive loss attributable to noncontrolling interest	4		0		4
Total comprehensive income (loss) attributable to Fannie Mae	18,843		(16,408)		(10,570)
Less: Net loss attributable to noncontrolling interest	4		0		4
Net income (loss) attributable to Fannie Mae	17,224		(16,855)		(14,014)
Preferred stock dividends	(11,603)		(9,614)		(7,704)
Undistributed earnings available for distribution to senior preferred stockholders	(4,224)		0		0
Net income (loss) attributable to common stockholders (Note 11)	$ 1,397		$ (26,469)		$ (21,718)
Earnings (loss) per share:
Basic	$ 0.24		$ (4.61)		$ (3.81)
Diluted	$ 0.24		$ (4.61)		$ (3.81)
Weighted-average common shares outstanding:
Basic	5,762	[2]	5,737	[2]	5,694	[2]
Diluted	5,893	[2]	5,737	[2]	5,694	[2]

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

[2] Includes 4.7 billion for the year ended December 31, 2012, and 4.6 billion for both the years ended December 31, 2011 and 2010 of weighted-average shares of common stock, that would be issued upon the full exercise of the warrant issued to Treasury from the date the warrant was issued through December 31, 2012, 2011 and 2010, respectively.