Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows provided by (used in) operating activities:
Net income	$ 10,955	$ 14,209	$ 83,982
Reconciliation of net income to net cash provided by (used in) operating activities:
Amortization of cost basis adjustments	(6,298)	(4,265)	(5,104)
Benefit for credit losses	(795)	(3,964)	(8,949)
Valuation gains	(510)	(2,159)	(2)
Current and deferred federal income taxes	4,083	4,126	(47,766)
Net change in trading securities	(10,153)	(2,666)	1,575
Net gains related to the disposition of acquired property and preforeclosure sales, including credit enhancements	(3,055)	(4,510)	(6,024)
Other, net	(900)	(2,109)	(4,809)
Net cash provided by (used in) operating activities	(6,673)	(1,338)	12,903
Cash flows provided by investing activities:
Purchases of trading securities held for investment	0	0	(7,521)
Proceeds from maturities and paydowns of trading securities held for investment	768	1,358	2,491
Proceeds from sales of trading securities held for investment	1,104	1,668	14,585
Proceeds from maturities and paydowns of available-for-sale securities	4,394	5,853	10,116
Proceeds from sales of available-for-sale securities	8,249	3,265	15,497
Purchases of loans held for investment	(187,194)	(132,650)	(195,386)
Net change in restricted cash	1,663	(3,547)	38,924
Advances to lenders	(118,746)	(100,045)	(139,162)
Proceeds from disposition of acquired property and preforeclosure sales	20,757	25,476	38,349
Net change in federal funds sold and securities purchased under agreements to resell or similar arrangements	3,600	8,025	(6,475)
Other, net	527	197	1,373
Net cash provided by investing activities	248,324	224,667	452,754
Cash flows used in financing activities:
Payments of cash dividends on senior preferred stock to Treasury	(10,278)	(20,594)	(82,452)
Other, net	26	70	(145)
Net cash used in financing activities	(249,000)	(220,534)	(467,546)
Net increase (decrease) in cash and cash equivalents	(7,349)	2,795	(1,889)
Cash and cash equivalents at beginning of period	22,023	19,228	21,117
Cash and cash equivalents at end of period	14,674	22,023	19,228
Cash paid during the period for:
Interest	104,928	108,667	109,240
Income taxes	1,170	2,815	2,350
Non-cash activities:
Net mortgage loans acquired by assuming debt	220,168	190,151	433,007
Net transfers from mortgage loans of Fannie Mae to mortgage loans of consolidated trusts	175,104	113,611	179,097
Transfers from advances to lenders to loans held for investment of consolidated trusts	114,851	93,909	137,074
Net transfers from mortgage loans to acquired property	17,534	24,742	34,024
Transfers of mortgage loans from held for investment to held for sale	8,601	2,194	1,341
Fannie Mae [Member]
Cash flows provided by investing activities:
Proceeds from repayments of loans acquired as held for investment	25,776	24,840	47,628
Proceeds from sales of loans acquired as held for investment	3,196	1,879	1,247
Cash flows used in financing activities:
Proceeds from the issuance of debt	443,371	380,282	372,361
Payments to redeem debt	(518,575)	(450,140)	(459,745)
Consolidated Trusts [Member]
Cash flows provided by investing activities:
Proceeds from repayments of loans acquired as held for investment	484,230	388,348	631,088
Cash flows used in financing activities:
Proceeds from the issuance of debt	347,614	275,353	409,979
Payments to redeem debt	$ (511,158)	$ (405,505)	$ (707,544)