Mortgage Loans - Non-accrual Loans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2021
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	$ 21,897	$ 12,233	$ 21,897	$ 12,233	$ 19,722	$ 12,517	$ 12,560	$ 20,496
Total interest income recognized	23	64	224	213
Single-family
Financing Receivable, Nonaccrual [Line Items]
Accrued interest receivable written off through the reversal of interest income:	80	14	233	46
Recorded investment in nonaccrual loans	20,371	11,002	20,371	11,002	18,274	10,317	11,243	19,237
Total interest income recognized	20	52	208	188
Single-family | 20- and 30-year or more, amortizing fixed-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	19,108	10,121	19,108	10,121	17,051	9,447	10,241	17,599
Total interest income recognized	19	48	197	175
Single-family | 15-year or less, amortizing fixed-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	638	235	638	235	565	200	245	430
Total interest income recognized	0	1	4	3
Single-family | Adjustable-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	99	55	99	55	85	53	59	107
Total interest income recognized	0	0	1	1
Single-family | Other
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	526	591	526	591	573	617	698	1,101
Total interest income recognized	1	3	6	9
Multifamily
Financing Receivable, Nonaccrual [Line Items]
Accrued interest receivable written off through the reversal of interest income:	3	1	36	1
Recorded investment in nonaccrual loans	1,526	1,231	1,526	1,231	$ 1,448	$ 2,200	$ 1,317	$ 1,259
Total interest income recognized	$ 3	$ 12	$ 16	$ 25