Allowance for Credit Losses - Details of the Allowance for Credit Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Rollforward of Allowance for Credit Losses
Beginning balance	$ 7,239	$ 6,849
Ending balance	8,505	7,239	$ 6,849
Allowance, Credit Loss
Rollforward of Allowance for Credit Losses
Beginning balance	7,239	6,849	7,893
Provision (benefit) for credit losses	1,290	476	(872)
Charge-offs	(604)	(513)	(643)
Recoveries collected	151	115	144
Other	429	312	327
Ending balance		7,239	6,849
Held-for-Investment
Rollforward of Allowance for Credit Losses
Beginning balance	6,774	6,383
Ending balance	7,968	6,774	6,383
Other Allowance for Credit Losses
Rollforward of Allowance for Credit Losses
Beginning balance	465	466
Ending balance	537	465	466
Single Family
Rollforward of Allowance for Credit Losses
Beginning balance	6,691	6,402
Charge-offs	(371)	(360)
Ending balance	7,549	6,691	6,402
Single Family | Allowance, Credit Loss
Rollforward of Allowance for Credit Losses
Beginning balance	6,691	6,402	7,746
Provision (benefit) for credit losses	758	374	(1,172)
Charge-offs	(478)	(511)	(643)
Recoveries collected	149	115	144
Other	429	311	327
Ending balance		6,691	6,402
Single Family | Held-for-Investment
Rollforward of Allowance for Credit Losses
Beginning balance	6,381	6,057
Ending balance	7,297	6,381	6,057
Single Family | Other Allowance for Credit Losses
Rollforward of Allowance for Credit Losses
Beginning balance	310	345
Ending balance	252	310	345
Multifamily
Rollforward of Allowance for Credit Losses
Beginning balance	548	447
Charge-offs	(126)	0
Ending balance	956	548	447
Multifamily | Allowance, Credit Loss
Rollforward of Allowance for Credit Losses
Beginning balance	548	447	147
Provision (benefit) for credit losses	532	102	300
Charge-offs	(126)	(2)	0
Recoveries collected	2	0	0
Other		1
Ending balance		548	447
Multifamily | Held-for-Investment
Rollforward of Allowance for Credit Losses
Beginning balance	393	326
Ending balance	671	393	326
Multifamily | Other Allowance for Credit Losses
Rollforward of Allowance for Credit Losses
Beginning balance	155	121
Ending balance	$ 285	$ 155	$ 121