Mortgage Loans - Non-accrual Loans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	$ 19,722	$ 12,560	$ 19,722	$ 12,560	$ 16,818	$ 12,517	$ 16,278	$ 20,496
Total interest income recognized	19	45	94	103
Single-family
Financing Receivable, Nonaccrual [Line Items]
Accrued interest receivable written off through the reversal of interest income:	74	15	153	32
Recorded investment in nonaccrual loans	18,274	11,243	18,274	11,243	15,277	10,317	15,020	19,237
Total interest income recognized	17	37	84	89
Single-family | 20- and 30-year or more, amortizing fixed-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	17,051	10,241	17,051	10,241	14,172	9,447	13,692	17,599
Total interest income recognized	15	34	79	82
Single-family | 15-year or less, amortizing fixed-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	565	245	565	245	429	200	331	430
Total interest income recognized	0	1	1	2
Single-family | Adjustable-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	85	59	85	59	75	53	84	107
Total interest income recognized	0	0	0	0
Single-family | Other
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	573	698	573	698	601	617	913	1,101
Total interest income recognized	2	2	4	5
Multifamily
Financing Receivable, Nonaccrual [Line Items]
Accrued interest receivable written off through the reversal of interest income:	33	1	35	1
Recorded investment in nonaccrual loans	1,448	1,317	1,448	1,317	$ 1,541	$ 2,200	$ 1,258	$ 1,259
Total interest income recognized	$ 2	$ 8	$ 10	$ 14