Consolidations and Transfers of Financial Assets Qualifying Sales of Portfolio Securitizations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Transfers and Servicing [Abstract]
Proceeds from the initial sale of securities from portfolio securitizations	$ 48	$ 183	$ 299	$ 479
Proceeds from portfolio securitizations accounted for as secured borrowings				421
Fair value of trading securities underlying the portfolio securitizations accounted for as secured borrowings	144		144
Unpaid principal balance of mortgage loans of consolidated trusts underlying the portfolio securitizations accounted for as secured borrowings	$ 168		$ 168

Represents the fair value of trading securities underlying securitization transactions that did not qualify as sales, but rather were accounted for as secured borrowings.

No definition available.

+ Details

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Period Type:	instant

- Definition

Represents proceeds from securitization transactions that did not qualify as sales, but rather were accounted for as secured borrowings. The proceeds were recorded as long-term debt of Fannie Mae in our consolidated balance sheet.

+ References

No definition available.

+ Details

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- Definition

Represents the unpaid principal balance of mortgage loans of unconsolidated trusts underlying securitization transactions that did not qualify as sales, but rather were accounted for as secured borrowings.

+ References

No definition available.

+ Details

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- Definition

Cash Flows between a transferor and a transferee attributable to newly transferred assets related to either a securitization, asset-backed financing arrangement, or similar transfer in which the transferor has continuing involvement with the transferred financial assets underlying the transaction (including, but not limited to, servicing, recourse, and restrictions on transferor's interests in the transferred financial assets).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph b

-URI http://asc.fasb.org/extlink&oid=13989330&loc=d3e107207-111719

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- Details

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