Mortgage Loans - Aging Analysis (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	$ 4,129,751	$ 3,973,024
Loans 90 Days or More Delinquent and Accruing Interest	14,448	27,302
Nonaccrual Loans with No Allowance	$ 3,697	7,179
Table Footnote
Serious delinquency: days past due	90 days
Total Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	$ 60,877	75,801
30 - 59 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	30,802	25,947
60 - 89 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	7,305	5,758
Seriously Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	22,770	44,096
Current
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	4,068,874	3,897,223
Single-family
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	3,697,529	3,566,819
Loans 90 Days or More Delinquent and Accruing Interest	14,437	26,985
Nonaccrual Loans with No Allowance	$ 3,684	$ 7,072
Single-family | Minimum
Table Footnote
Serious delinquency: days past due	90 days	90 days
Single-family | Total Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	$ 59,749	$ 73,994
Single-family | 30 - 59 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	30,629	25,833
Single-family | 60 - 89 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	7,305	5,758
Single-family | Seriously Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	21,815	42,403
Single-family | Current
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	3,637,780	3,492,825
Single-family | 20- and 30-year or more, amortizing fixed-rate
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	3,146,854	2,969,105
Loans 90 Days or More Delinquent and Accruing Interest	13,257	24,236
Nonaccrual Loans with No Allowance	3,254	6,271
Single-family | 20- and 30-year or more, amortizing fixed-rate | Total Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	54,655	66,342
Single-family | 20- and 30-year or more, amortizing fixed-rate | 30 - 59 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	27,891	22,862
Single-family | 20- and 30-year or more, amortizing fixed-rate | 60 - 89 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	6,774	5,192
Single-family | 20- and 30-year or more, amortizing fixed-rate | Seriously Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	19,990	38,288
Single-family | 20- and 30-year or more, amortizing fixed-rate | Current
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	3,092,199	2,902,763
Single-family | 15-year or less, amortizing fixed-rate
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	491,468	533,427
Loans 90 Days or More Delinquent and Accruing Interest	666	1,454
Nonaccrual Loans with No Allowance	82	193
Single-family | 15-year or less, amortizing fixed-rate | Total Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	3,016	4,149
Single-family | 15-year or less, amortizing fixed-rate | 30 - 59 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	1,902	2,024
Single-family | 15-year or less, amortizing fixed-rate | 60 - 89 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	314	326
Single-family | 15-year or less, amortizing fixed-rate | Seriously Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	800	1,799
Single-family | 15-year or less, amortizing fixed-rate | Current
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	488,452	529,278
Single-family | Adjustable-rate
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	27,108	26,342
Loans 90 Days or More Delinquent and Accruing Interest	90	287
Nonaccrual Loans with No Allowance	24	63
Single-family | Adjustable-rate | Total Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	341	571
Single-family | Adjustable-rate | 30 - 59 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	176	161
Single-family | Adjustable-rate | 60 - 89 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	38	36
Single-family | Adjustable-rate | Seriously Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	127	374
Single-family | Adjustable-rate | Current
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	26,767	25,771
Single-family | Other
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	32,099	37,945
Loans 90 Days or More Delinquent and Accruing Interest	424	1,008
Nonaccrual Loans with No Allowance	324	545
Single-family | Other | Total Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	1,737	2,932
Single-family | Other | 30 - 59 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	660	786
Single-family | Other | 60 - 89 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	179	204
Single-family | Other | Seriously Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	898	1,942
Single-family | Other | Current
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	30,362	35,013
Multifamily
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	432,222	406,205
Loans 90 Days or More Delinquent and Accruing Interest	11	317
Nonaccrual Loans with No Allowance	$ 13	107
Multifamily | Minimum
Table Footnote
Serious delinquency: days past due	60 days
Multifamily | Maximum
Table Footnote
Serious delinquency: days past due	89 days
Multifamily | Total Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	$ 1,128	1,807
Multifamily | 30 - 59 Days Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	173	114
Multifamily | Seriously Delinquent
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	955	1,693
Multifamily | Current
Financing Receivable, Past Due [Line Items]
Loans held for investment, excluding fair value option	$ 431,094	$ 404,398