Mortgage Loans - Nonaccrual Loans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Financing Receivable, Nonaccrual [Line Items]
Amortized cost, nonaccrual loans	$ 30,760	$ 29,101	$ 25,205	$ 12,517
Interest income recognized, nonaccrual loans	577	560	441
Single-family
Financing Receivable, Nonaccrual [Line Items]
Accrued interest receivable written off	412	391	325
Amortized cost, nonaccrual loans	27,448	26,584	23,315	10,317
Interest income recognized, nonaccrual loans	534	505	400
Single-family | 20- and 30-year or more, amortizing fixed-rate
Financing Receivable, Nonaccrual [Line Items]
Amortized cost, nonaccrual loans	26,221	25,218	21,971	9,447
Interest income recognized, nonaccrual loans	513	481	379
Single-family | 15-year or less, amortizing fixed-rate
Financing Receivable, Nonaccrual [Line Items]
Amortized cost, nonaccrual loans	692	770	727	200
Interest income recognized, nonaccrual loans	10	11	9
Single-family | Adjustable-rate
Financing Receivable, Nonaccrual [Line Items]
Amortized cost, nonaccrual loans	114	114	109	53
Interest income recognized, nonaccrual loans	3	3	2
Single-family | Other
Financing Receivable, Nonaccrual [Line Items]
Amortized cost, nonaccrual loans	421	482	508	617
Interest income recognized, nonaccrual loans	8	10	10
Multifamily
Financing Receivable, Nonaccrual [Line Items]
Accrued interest receivable written off	35	32	49
Amortized cost, nonaccrual loans	3,312	2,517	1,890	$ 2,200
Interest income recognized, nonaccrual loans	$ 43	$ 55	$ 41