Mortgage Loans - Non-accrual Loans (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	$ 25,853	$ 16,818	$ 25,205	$ 12,517
Total interest income recognized	42	38
Single-family
Financing Receivable, Nonaccrual [Line Items]
Accrued interest receivable written off through the reversal of interest income:	82	79
Recorded investment in nonaccrual loans	24,041	15,277	23,315	10,317
Total interest income recognized	40	9
Single-family | 20- and 30-year or more, amortizing fixed-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	22,712	14,172	21,971	9,447
Total interest income recognized	38	7
Single-family | 15-year or less, amortizing fixed-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	734	429	727	200
Total interest income recognized	1	0
Single-family | Adjustable-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	115	75	109	53
Total interest income recognized	0	0
Single-family | Other
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	480	601	508	617
Total interest income recognized	1	2
Multifamily
Financing Receivable, Nonaccrual [Line Items]
Accrued interest receivable written off through the reversal of interest income:	3	2
Recorded investment in nonaccrual loans	1,812	1,541	$ 1,890	$ 2,200
Total interest income recognized	$ 2	$ 29