Mortgage Loans - Non-accrual Loans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	$ 12,560	$ 29,484	$ 12,560	$ 29,484	$ 16,278	$ 20,496	$ 36,138	$ 28,574
Total interest income recognized	45	107	103	208
Single-family
Financing Receivable, Nonaccrual [Line Items]
Accrued interest receivable written off through the reversal of interest income:	15	21	32	129
Recorded investment in nonaccrual loans	11,243	27,264	11,243	27,264	15,020	19,237	33,985	26,505
Total interest income recognized	37	103	89	195
Single-family | 20- and 30-year or more, amortizing fixed-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	10,241	24,728	10,241	24,728	13,692	17,599	30,173	22,907
Total interest income recognized	34	95	82	180
Single-family | 15-year or less, amortizing fixed-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	245	596	245	596	331	430	945	853
Total interest income recognized	1	2	2	3
Single-family | Adjustable-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	59	179	59	179	84	107	284	270
Total interest income recognized	0	0	0	1
Single-family | Other
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	698	1,761	698	1,761	913	1,101	2,583	2,475
Total interest income recognized	2	6	5	11
Multifamily
Financing Receivable, Nonaccrual [Line Items]
Accrued interest receivable written off through the reversal of interest income:	1	0	1	1
Recorded investment in nonaccrual loans	1,317	2,220	1,317	2,220	$ 1,258	$ 1,259	$ 2,153	$ 2,069
Total interest income recognized	$ 8	$ 4	$ 14	$ 13