Summary of Significant Accounting Policies - Narrative (Details) $ in Millions |
12 Months Ended | |
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Dec. 31, 2025
USD ($)
segment
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Dec. 31, 2024
USD ($)
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| Accounting Policies [Abstract] | ||
| Number of reportable segments | segment | 2 | |
| Acquired property, net | $ 1,900 | $ 1,700 |
| Early lender funding advances, maximum term | 60 days | |
| Schedule of Investments in Trading Securities [Line Items] | ||
| Investment in securities, trading, at fair value | $ 69,514 | 78,728 |
| Securities received as collateral | 45,600 | 56,300 |
| Fair value of securities received as collateral that can be resold or repledged | 43,400 | 49,000 |
| Non-mortgage-related securities | ||
| Schedule of Investments in Trading Securities [Line Items] | ||
| Investment in securities, trading, at fair value | 55,223 | 77,630 |
| Non-mortgage-related securities | Pledged as collateral | ||
| Schedule of Investments in Trading Securities [Line Items] | ||
| Investment in securities, trading, at fair value | $ 8,200 | $ 8,900 |
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- Definition Represent the maximum number of days the lenders have when we provide early funding to lenders for loans that they will subsequently either sell to us or securitize into a Fannie Mae MBS that they will deliver to us. No definition available.
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- References No definition available.
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- Definition Fair value of collateral permitted, by contact or custom, to be sold or re-pledged. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Carrying amount as of the balance sheet date of land and buildings obtained through foreclosure proceedings or defeasance in full or partial satisfaction of a debt arrangement. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The carrying value as of the balance sheet date of the assets received as collateral against securities loaned to other broker-dealers. Borrowers of securities generally are required to provide collateral to the lenders of securities, commonly cash but sometimes other securities or standby letters of credit, with a value slightly higher than that of the securities borrowed. In instances where the entity is permitted to sell or re-pledge these securities, the entity reports the fair value of the collateral received and the related obligation to return the collateral as a liability. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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