Segment Reporting - Segment Assets (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Segment Reporting, Asset Reconciling Item [Line Items]
Total Assets	$ 3,468,187	$ 3,386,692
Reconciling items
Segment Reporting, Asset Reconciling Item [Line Items]
Total Assets	(153,098)	(184,117)
Single Family Guarantee Segment \| Operating segments
Segment Reporting, Asset Reconciling Item [Line Items]
Total Assets	3,141,321	3,104,174
Multifamily \| Operating segments
Segment Reporting, Asset Reconciling Item [Line Items]
Total Assets	479,964	466,635
Operating segments \| Operating segments
Segment Reporting, Asset Reconciling Item [Line Items]
Total Assets	$ 3,621,285	$ 3,570,809

Amount of asset recognized for present right to economic benefit.

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+ Details