FANNIE MAE COMMITMENTS AND PLEDGED SECURITIES - Commitments (Detail) $ in Millions	9 Months Ended
Sep. 30, 2023 USD ($)
Fannie Mae, Freddie Mac, HUD and Ginnie Mae
LITIGATION, COMMITMENTS, AND CONTINGENCIES
Operational liquidity	$ 186.4
DUS Risk-Sharing Obligations \| Fannie Mae
LITIGATION, COMMITMENTS, AND CONTINGENCIES
Period of funding for collateral requirement	48 months
Amount of additional capital required to be funded over the next 48 months	$ 79.6
Net worth	1,000.0
Minimum liquid assets to be maintained to meet operational liquidity requirements	60.0
DUS Risk-Sharing Obligations \| Fannie Mae \| Minimum
LITIGATION, COMMITMENTS, AND CONTINGENCIES
Net worth requirement	$ 301.6
DUS Risk-Sharing Obligations \| Fannie Mae \| New Tier 2 loans
LITIGATION, COMMITMENTS, AND CONTINGENCIES
Collateral requirements percentage	0.75%
Period of funding for collateral requirement	48 months
DUS Risk-Sharing Obligations \| Fannie Mae \| New Tier 2 loans \| Money Market Funds
LITIGATION, COMMITMENTS, AND CONTINGENCIES
Restricted liquidity collateral reduction percentage	5.00%
DUS Risk-Sharing Obligations \| Fannie Mae \| New Tier 2 loans \| Agency Mortgage Backed Securities
LITIGATION, COMMITMENTS, AND CONTINGENCIES
Restricted liquidity collateral reduction percentage	4.00%

Amount of net capital of broker-dealer.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Rule 15c3-1
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