Allowance for Loan Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Allowance for Loan Losses [Roll Forward]
Beginning balance	$ (5,629)	$ (10,552)	$ (9,016)
Benefit (provision) for loan losses	(6,306)	5,022	(466)
Write-offs	926	476	593
Recoveries	(299)	(468)	(94)
Other	(39)	(107)	153
Ending balance	(11,347)	(5,629)	(10,552)
Unpaid principal balance of mortgage loans	4,075,598	3,899,025
Multifamily
Allowance for Loan Losses [Roll Forward]
Unpaid principal balance of mortgage loans	431,440	403,452
Multifamily | Seniors housing portfolio | Adjustable-rate
Allowance for Loan Losses [Roll Forward]
Unpaid principal balance of mortgage loans	$ 16,600
Percentage of book of business	39.00%
Transition impact of the adoption of the CECL standard
Allowance for Loan Losses [Roll Forward]
Beginning balance	$ 0	0	(1,722)
Ending balance		0	0
Single-family
Allowance for Loan Losses [Roll Forward]
Beginning balance	(4,950)	(9,344)	(8,759)
Benefit (provision) for loan losses	(5,061)	4,503	127
Write-offs	883	417	457
Recoveries	(276)	(419)	(93)
Other	(39)	(107)	153
Ending balance	(9,443)	(4,950)	(9,344)
Single-family | Transition impact of the adoption of the CECL standard
Allowance for Loan Losses [Roll Forward]
Beginning balance	0	0	(1,229)
Ending balance		0	0
Multifamily
Allowance for Loan Losses [Roll Forward]
Beginning balance	(679)	(1,208)	(257)
Benefit (provision) for loan losses	(1,245)	519	(593)
Write-offs	43	59	136
Recoveries	(23)	(49)	(1)
Ending balance	(1,904)	(679)	(1,208)
Multifamily | Transition impact of the adoption of the CECL standard
Allowance for Loan Losses [Roll Forward]
Beginning balance	$ 0	0	(493)
Ending balance		$ 0	$ 0