Mortgage Loans - Non-accrual Loans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	$ 25,336	$ 19,722	$ 25,336	$ 19,722	$ 25,853	$ 25,205	$ 16,818	$ 12,517
Total interest income recognized	72	19	158	94
Single-family
Financing Receivable, Nonaccrual [Line Items]
Accrued interest receivable written off through the reversal of interest income:	97	74	179	153
Recorded investment in nonaccrual loans	23,500	18,274	23,500	18,274	24,041	23,315	15,277	10,317
Total interest income recognized	48	17	132	84
Single-family | 20- and 30-year or more, amortizing fixed-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	22,183	17,051	22,183	17,051	22,712	21,971	14,172	9,447
Total interest income recognized	45	15	124	79
Single-family | 15-year or less, amortizing fixed-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	704	565	704	565	734	727	429	200
Total interest income recognized	1	0	3	1
Single-family | Adjustable-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	117	85	117	85	115	109	75	53
Total interest income recognized	0	0	1	0
Single-family | Other
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	496	573	496	573	480	508	601	617
Total interest income recognized	2	2	4	4
Multifamily
Financing Receivable, Nonaccrual [Line Items]
Accrued interest receivable written off through the reversal of interest income:	4	33	6	35
Recorded investment in nonaccrual loans	1,836	1,448	1,836	1,448	$ 1,812	$ 1,890	$ 1,541	$ 2,200
Total interest income recognized	$ 24	$ 2	$ 26	$ 10