Mortgage Loans - Non-accrual Loans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	$ 29,563	$ 25,336	$ 29,563	$ 25,336	$ 30,393	$ 29,101	$ 25,853	$ 25,205
Total interest income recognized	64	72	162	158
Single-family
Financing Receivable, Nonaccrual [Line Items]
Accrued interest receivable written off through the reversal of interest income:	91	97	194	179
Recorded investment in nonaccrual loans	26,701	23,500	26,701	23,500	27,691	26,584	24,041	23,315
Total interest income recognized	58	48	155	132
Single-family | 20- and 30-year or more, amortizing fixed-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	25,423	22,183	25,423	22,183	26,335	25,218	22,712	21,971
Total interest income recognized	56	45	148	124
Single-family | 15-year or less, amortizing fixed-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	736	704	736	704	771	770	734	727
Total interest income recognized	1	1	3	3
Single-family | Adjustable-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	114	117	114	117	122	114	115	109
Total interest income recognized	0	0	1	1
Single-family | Other
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	428	496	428	496	463	482	480	508
Total interest income recognized	1	2	3	4
Multifamily
Financing Receivable, Nonaccrual [Line Items]
Accrued interest receivable written off through the reversal of interest income:	9	4	17	6
Recorded investment in nonaccrual loans	2,862	1,836	2,862	1,836	$ 2,702	$ 2,517	$ 1,812	$ 1,890
Total interest income recognized	$ 6	$ 24	$ 7	$ 26