Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (Unaudited) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011		Jun. 30, 2012	Jun. 30, 2011
Interest income:
Trading securities	$ 73	$ 264		$ 522	$ 548
Available-for-sale securities	1,035	1,152		1,762	2,365
Mortgage loans (includes $28,424 and $31,613, respectively, for the three months ended and $57,425 and $63,478, respectively, for the six months ended related to consolidated trusts)	32,023	35,333		64,593	70,923
Other	40	25		78	53
Total interest income	33,171	36,774		66,955	73,889
Interest expense:
Short-term debt	32	81		74	188
Long-term debt (includes $24,714 and $27,919, respectively, for the three months ended and $50,074 and $55,771, respectively, for the six months ended related to consolidated trusts)	27,711	31,721		56,256	63,769
Total interest expense	27,743	31,802		56,330	63,957
Net interest income	5,428	4,972		10,625	9,932
Benefit (provision) for credit losses	3,041	(6,537)	[1]	1,041	(17,091)	[1]
Net interest income (loss) after benefit (provision) for credit losses	8,469	(1,565)		11,666	(7,159)
Investment gains, net	131	171		247	246
Other-than-temporary impairments	(196)	(28)		(276)	(85)
Noncredit portion of other-than-temporary impairments recognized in other comprehensive income	(403)	(28)		(387)	(15)
Net other-than-temporary impairments	(599)	(56)		(663)	(100)
Fair value gains (losses), net	(2,449)	(1,634)		(2,166)	(1,345)
Debt extinguishment (losses) gains, net	(93)	(43)		(127)	(30)
Fee and other income (expense)	395	265		770	502
Non-interest income (loss)	(2,615)	(1,297)		(1,939)	(727)
Administrative expenses:
Salaries and employee benefits	292	310		598	630
Professional services	179	169		347	358
Occupancy expenses	48	43		91	85
Other administrative expenses	48	47		95	101
Total administrative expenses	567	569		1,131	1,174
Foreclosed property expense (income)	(70)	(478)		269	10
Other expenses	238	32		490	384
Total expenses	735	123		1,890	1,568
Income (loss) before federal income taxes	5,119	(2,985)		7,837	(9,454)
(Benefit) provision for federal income taxes	0	(93)		0	(91)
Net income (loss)	5,119	(2,892)		7,837	(9,363)
Other comprehensive income (loss):
Changes in unrealized losses on available-for-sale securities, net of reclassification adjustments and taxes	320	(1)		675	178
Other	8	3		15	5
Total other comprehensive income (loss)	328	2		690	183
Total comprehensive income (loss)	5,447	(2,890)		8,527	(9,180)
Less: Comprehensive (income) loss attributable to the noncontrolling interest	(5)	(1)		(4)	(1)
Total comprehensive income (loss) attributable to Fannie Mae	5,442	(2,891)		8,523	(9,181)
Net income (loss)	5,119	(2,892)		7,837	(9,363)
Less: Net (income) loss attributable to the noncontrolling interest	(5)	(1)		(4)	(1)
Net (loss) income attributable to Fannie Mae	5,114	(2,893)		7,833	(9,364)
Preferred stock dividends	(2,929)	(2,282)		(5,746)	(4,498)
Net income (loss) attributable to common stockholders	$ 2,185	$ (5,175)		$ 2,087	$ (13,862)
Earnings (loss) per share, Basic	$ 0.38	$ (0.90)		$ 0.36	$ (2.43)
Earnings (loss) per share, Diluted	$ 0.37	$ (0.90)		$ 0.35	$ (2.43)
Weighted-average common shares outstanding, Basic	5,762	5,730		5,762	5,714
Weighted-average common shares outstanding, Diluted	5,893	5,730		5,893	5,714

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