Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Net cash used in operating activities
Net cash used in operating activities	$ (1,249)	$ (1,321)
Cash flows provided by investing activities:
Proceeds from maturities and paydowns of trading securities held for investment	296	333
Proceeds from sales of trading securities held for investment	483	486
Proceeds from maturities and paydowns of available-for-sale securities	1,232	1,446
Proceeds from sales of available-for-sale securities	2,171	35
Purchases of loans held for investment	(44,460)	(24,486)
Net change in restricted cash	(8,897)	4,412
Advances to lenders	(30,804)fnm_PaymentsForAdvancesToLenders	(20,501)fnm_PaymentsForAdvancesToLenders
Proceeds from disposition of acquired property and preforeclosure sales	5,490	6,329
Net change in federal funds sold and securities purchased under agreements to resell or similar arrangements	10,720	26,225
Other, net	154	(385)
Net cash provided by investing activities	66,582	80,721
Cash flows used in financing activities:
Payments of cash dividends on senior preferred stock to Treasury	(1,920)	(7,191)
Other, net	31	18
Net cash used in financing activities	(63,496)	(84,572)
Net increase (decrease) in cash and cash equivalents	1,837	(5,172)
Cash and cash equivalents at beginning of period	22,023	19,228
Cash and cash equivalents at end of period	23,860	14,056
Cash paid during the period for:
Interest	26,235us-gaap_InterestPaid	26,567us-gaap_InterestPaid
Income Taxes	0us-gaap_IncomeTaxesPaid	425us-gaap_IncomeTaxesPaid
Fannie Mae [Member]
Cash flows provided by investing activities:
Proceeds from repayments and sales of loans acquired as held for investment of Fannie Mae	5,348	6,217
Cash flows used in financing activities:
Proceeds from issuance of debt	114,467	69,086
Payments to redeem debt	(126,608)	(117,058)
Consolidated Trusts [Member]
Cash flows provided by investing activities:
Proceeds from repayments and sales of loans acquired as held for investment of consolidated trusts	124,849	80,610
Cash flows used in financing activities:
Proceeds from issuance of debt	68,943	58,216
Payments to redeem debt	$ (118,409)	$ (87,643)

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The net cash outflow or inflow from other investing activities. This element is used when there is not a more specific and appropriate element in the taxonomy.

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