Mortgage Loans - Nonaccrual Loans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Nonaccrual [Line Items]
Amortized cost, nonaccrual loans	$ 25,205	$ 12,517	$ 20,496	$ 28,574
Interest income recognized, nonaccrual loans	441	298	328
Single-family
Financing Receivable, Nonaccrual [Line Items]
Accrued interest receivable written off	325	61	163
Amortized cost, nonaccrual loans	23,315	10,317	19,237	26,505
Interest income recognized, nonaccrual loans	400	223	314
Single-family | 20- and 30-year or more, amortizing fixed-rate
Financing Receivable, Nonaccrual [Line Items]
Amortized cost, nonaccrual loans	21,971	9,447	17,599	22,907
Interest income recognized, nonaccrual loans	379	207	292
Single-family | 15-year or less, amortizing fixed-rate
Financing Receivable, Nonaccrual [Line Items]
Amortized cost, nonaccrual loans	727	200	430	853
Interest income recognized, nonaccrual loans	9	4	6
Single-family | Adjustable-rate
Financing Receivable, Nonaccrual [Line Items]
Amortized cost, nonaccrual loans	109	53	107	270
Interest income recognized, nonaccrual loans	2	1	1
Single-family | Other
Financing Receivable, Nonaccrual [Line Items]
Amortized cost, nonaccrual loans	508	617	1,101	2,475
Interest income recognized, nonaccrual loans	10	11	15
Multifamily
Financing Receivable, Nonaccrual [Line Items]
Accrued interest receivable written off	49	1	1
Amortized cost, nonaccrual loans	1,890	2,200	1,259	$ 2,069
Interest income recognized, nonaccrual loans	$ 41	$ 75	$ 14