Mortgage Loans - Loans Purchased and Sold (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Single-family \| Held for Investment
Financing Receivable, Allowance for Credit Loss [Line Items]
Purchases	$ 93,603	$ 85,239	$ 171,249	$ 147,508
Single-family \| Held-for-Sale
Financing Receivable, Allowance for Credit Loss [Line Items]
Sales	496	381	1,255	999
Multifamily \| Held for Investment
Financing Receivable, Allowance for Credit Loss [Line Items]
Purchases	8,663	3,791	12,577	6,416
Multifamily \| Held-for-Sale
Financing Receivable, Allowance for Credit Loss [Line Items]
Purchases	2,096	6,581	7,527	13,040
Sales	$ 8,247	$ 6,462	$ 14,851	$ 13,065

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.

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